International Stem Cell Corp’s Parthenogenetic Stem Cells to Be Used in A Clinical Trial to Treat Parkinson’s Disease Patients


The Australian government has recently given its approval for a clinical trial of what is almost certainly a medical first. The Carlsbad-based stem cell company, International Stem Cell Corp. (ISCO), a publicly traded biotechnology company, has developed a unique stem cell technology to address particular conditions.

The clinical trial that has been approved will examine the use the ISCO’s unique stem cell products in the treatment of Parkinson’s disease. Twelve Parkinson’s patients will receive implantations of these cells sometime in the first quarter of 2016, according to Russell Kern, ISCO’s chief scientific officer. The implanted cells will be neural precursor cells, which are slightly immature neurons that will complete their maturation in the brain, hopefully into dopamingergic neurons, which are the precise kind of neurons that die off in patients with Parkinson’s disease.

Parkinson’s disease (PD) is a progressive disorder of the nervous system that affects voluntary movement. PD develops gradually and sometimes begins with a slight tremor in only one hand, but PD may also cause stiffness or slowing of movement. PD worsens over time.

PD patients suffer from tremor, or shaking of the limbs, particularly when it is relaxed and at rest. Over time, PD reduces the ability to move and slows movement (bradykinesis) which makes simple tasks difficult and time-consuming. Muscle stiffness may occur and this limits the range of motion and causes pain. PD patients also suffer from stooping posture and balance problems and a decreased ability to perform unconscious movements. For example, they have trouble swinging their arms while they walk, blinking, or smiling. They might also experience speech problems that can range from slurring of the speech to monotone speech devoid of inflexions, or softer speech with hesitations before speaking. Writing might also become problematic.

PD is caused by the gradual death of neurons in the midbrain that produce a chemical messenger called dopamine. The drop in dopamine levels in the system of the brain that controls voluntary movement leading to the signs and symptoms of Parkinson’s disease.

Several different animal experiments with a variety different cell types have established that transplantation to dopamine-making neuronal precursors into the midbrains of laboratory animals with artificially-induced PD can reverse the symptoms of PD. Dopaminergic neurons can be derived from embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), umbilical cord blood hematopoietic stem cells (HSCs), induced pluripotent stem cells (iPSCs), and NSCs (see Petit G. H., Olsson T. T., Brundin P. Neuropathology and Applied Neurobiology. 2014;40(1):60–67). Also, since the 1980s, various cell sources have been tested, including autografts of adrenal medulla, sympathetic ganglion, carotid body-derived cells, xenografts of fetal porcine ventral mesencephalon, and allografts of human fetal ventral mesencephalon (fVM) tissues have been implanted into the midbrains of PD patients (Buttery PC, Barker RA. J Comp Neurol. 2014 Aug 15;522(12):2802-16). While the results of these trials were varied and not terribly reproducible, these studies did show that the signs and symptoms of PD could be reversed, in some people, by implanting dopamine-making neurons into the midbrains of PD patients.

ISCO has derived neural precursor cells from a completely new source. ISCO scientists have taken unfertilized eggs from human egg donors and artificially activated them so that they self-fertilize, and then begin dividing until they form a blastocyst-stage embryo from which stem cells are derived. This new class of stem cells, which were pioneered by ISCO, human parthenogenetic stem cells (hpSCs) have the best characteristics of each of the other classes of stem cells. Since these stem cells are created by chemically stimulating the oocytes (eggs) to begin division, the oocytes are not fertilized and no viable embryo is created or destroyed. This process is called parthenogenesis and parthenogenetic stem cells derived from the parthenogenetically-activated oocytes, are produced from unfertilized human egg cells.

The stem cells are created by chemically stimulating the oocytes (eggs) to begin division.  The oocytes are not fertilized and no viable embryo is created or destroyed.
The stem cells are created by chemically stimulating the oocytes (eggs) to begin division. The oocytes are not fertilized and no viable embryo is created or destroyed.

Why did ISCO decide to do this trial in Australia? According to Kern, ISCO chose to conduct their clinical trial in Australia because its clinical trial system is more “interactive,” which allows for better collaboration with Australia’s Therapeutic Goods Administration on trial design. This clinical trial, in fact, is the first stem cell trial for PD according to the clinical trial tracking site clinicaltrials.gov. The test will be conducted by ISCO’s Australian subsidiary, Cyto Therapeutics.

The approach pioneered in this clinical trial might cure or even provide an extended period of relief from the symptoms of PD. If this clinical trial succeeds, the stem cell clinical trial dam might very well break and we will see proposed clinical trials that test stem cell-based treatments for other neurodegenerative diseases such as Huntington’s disease, Lou Gehrig’s disease (ALS), frontotemporal dementia, or even Alzheimer’s disease.

ISCO has spent many years developing their parthenogenetic technology with meager financing. However the company’s total market value amounts to something close to $11.1 million, presently.

hpSCs are pluripotent like embryonic stem cells. Because they are being used in the brain, they will not be exposed to the immune system. Therefore an exact tissue type match is not necessary for this type of transplantation. In their publications, ISCO scientists have found their cells to be quite stable, but other research groups who have worked with stem cells derived from parthenogenetically-activated embryos have found such cells to be less stable than other types of pluripotent stem cells. The stability of the ISCO hpSCs remains an open question. The lack of a paternal genome might pose a safety challenge for the use of hpSCs.

Rita Vassena and her colleagues in the laboratory of Juan Carlos Izpisua Belmonte at the Salk Institute for Biological Studies in La Jolla, CA examined the gene expression patterns of mesenchymal stem cells derived from hpSCs and found that the overall gene expression patterns were similar to MSCs made from embryonic stem cells or induced pluripotent stem cells. However, upon further differentiation and manipulation, the gene expression patterns of the cells began to show more variability and further depart from normal gene expression patterns (Vassena R, et al Human Molecular Genetics 2012; 21(15): 3366-3373). Therefore, the derivatives of hpSCs might not be as stable as cellular derivatives from other types of stem cells. The good news about hpSCs established from parthenogenetic ESCs were reported to be morphologically indistinguishable from embryonic stem cells derived from fertilized embryos, and seem to show normal gene expression or even correct genomic imprinting in chimeras, when pESCs were used in tissue contribution (T.Horii, et al Stem Cells, vol. 26, no. 1, pp. 79–88, 2008).

For those of us who view the early embryo as the youngest members of the human community who have the right not to be harmed, hpSCs made by ISCO remove this objection, since their derivation does not involve the death of any embryos.

The ISCO approach to Parkinson’s is similar to that of a San Diego group called Summit for Stem Cell, which is going to use induced pluripotent stem cell derivatives. This nonprofit organization is presently raising money for a clinical trial to test the efficacy of their treatment.

Both groups intend to transplant the cells while they are still slightly immature, so that they can complete their development in the brain. Animal studies suggest that implanting immature precursors are better than transplanting mature dopaminergic neurons into the midbrain. The precursors then differentiate into dopamine-making neurons, and other cells differentiate into supportive glial cells, which support the dopamine-making neurons.

“It’s a dual action,” Kern said. “Also, neural stem cells reduce inflammation, and inflammation is huge in Parkinson’s.”

Summit 4 Stem Cell will also take a similar approach, according to stem cell scientist Jeanne Loring, a leader of the Summit 4 Stem Cell project. The cells make proper connections with the brain better when they are still maturing, said Loring, who’s also head of the regenerative medicine program at The Scripps Research Institute in La Jolla. This is all provided that Summit 4 Stem Cell can raise the millions of dollars required for the clinical trial and secure the required approvals from the U.S. Food and Drug Administration.

Loring said she views ISCO as a partner in fighting Parkinson’s. One of her former students is working for the company, she said. “The whole idea is to treat patients by whatever means possible,” Loring said.

ISCO’s choice of Australia for its streamlined regulatory process makes sense, Loring said. Her team, with U.S.-based academics and medical professionals, doesn’t have the same flexibility as ISCO in looking for clinical trial locations, she said.

Transplantation of Unique, Newly Discovered Stem Cells May Lead to Promising Stroke Therapy


Stroke treatments have seen some remarkable advances in the past few years. Stem cell treatments for stroke have even seen some successes in clinical trials, showing that stem cell transplantation aimed at neural repair after a stroke is a possible way to ameliorate the effects of stroke.

Now, collaboration between teams of American and Japanese researchers has shown that a newly-identified stem cell has the ability to successfully treat stroke in rats. When administered to rats who have suffered from an experimentally-induced stroke, MUSE or multilineage-differentiating stress-enduring cells induced the regeneration of neurons and resulted in “significant improvements in neurological and motor functions” compared to control groups that were not transplanted with MUSE cells. MUSE cells also do not cause tumors.

The study has increased the number of therapeutic arrows in the quiver of neurologists and neuroscientists and lengthens the list of cells that might one day be considered for human clinical trials if continued pre-clinical tests prove successful. Future clinical studies aimed at regenerating neurological and motor function in patients who have suffered ischemic stroke.

The paper describing this study appeared in a recent issue of Stem Cells (Sept. 2015).

“Muse cells are unique stem cells that are able to self-renew and display high-efficiency for differentiating into neuron-like cells,” explained lead author Dr. Cesar V Borlongan, Distinguished Professor and Vice-Chairman for Research at the University of South Florida (USF) College of Medicine Department of Neurosurgery and Brain Repair and Director of USF’s the Center of Excellence for Aging and Brain Repair. “Unlike mesenchymal stem cells (MSCs) that have previously been used in stem cell transplantation in stroke-related clinical trials, in the present study Muse cells were found to possess functional characteristics of neurons as they attain the attributes of the host microenvironment. When MUSEcells were transplanted into to the brains of rats modeled with stroke, they attained neuronal characteristics.”

MUSE cells are found in many different tissues, including bone marrow, skin and fat. Since these cells can be derived from dermal fibroblasts (a type of connective tissue cell that provides the structural framework for animal tissues and plays a critical role in wound healing), they can be accessed with relative ease, without the need for the painful, invasive procedures required for obtaining other kinds of stem cells. Furthermore, while some stem cells used in stem cell transplantation studies have been found to cause cancer, MUSE cells do not produce tumors and exhibit exceptional tissue repair potential when introduced into the blood stream.

Some researchers think that fetal stem cells might be better candidates for replacing lost neural circuitry. The main reason in favor of fetal stem cells is that they preferentially differentiate into neuronal cells. However, the accessibility to fetal stem cells is limited and, like embryonic stem cells, the immaturity of these cells may present safety issues, such as tumor development. Additionally, the use of fetal and embryonic stem cells has many ethical difficulties to say the least. Since MUSE cells can be derived from adult tissue rather than fetal or embryonic tissue, the ethical quandaries associated with using them is minimal.

Not only do MUSE cells also have the practical advantage of being non-tumorigenic, they are readily accessed commercially and can also be easily collected from patient skin biopsies. MUSE cells also do not have to be “induced,” or genetically manipulated in order to be used, since they already display inherent stem cell properties after isolation. MUSE cells also spontaneously home toward the stroke-damaged sites.

“Ours is the first study to show that human skin fibroblast-derived Muse cells can have neuron-like function, possess an inherent ability to assume ‘stemness’ properties, and to readily differentiate into neural-lineage cells after integration into the stroke brain,” said co-lead author Dr. Mari Dezawa, Department of Stem Cell Biology and Histology, Tohoku University Graduate School of Medicine in Sendai, Japan. “Our results show that Muse cells are a feasible and promising source for cell-based approaches to ischemic stroke therapy.”

Added Netrin-1 Increases Induced Pluripotent Stem Cell Production Without Affecting Stem Cell Quality


Since 2006, stem cell researchers have succeeded in generating induced pluripotent cells (iPS cells) from mature, adult cells. These cells have enormous potential applications, particularly for regenerative medicine. However, the process by which these cells are made still requires further tweaking in order to increase its efficiency and safety. Recently, two teams of researchers from Inserm, CNRS, Centre Léon Bérard and Claude Bernard Lyon 1 University have discovered a molecule that seems to favor the production of iPS cells. Their work was published in the journal Nature Communications.

Reprogramming an already specialized cell into a pluripotent stem cell was discovered in 2006 by the Japanese scientist Shinya Yamanaka. His iPS cells were capable of differentiating into any type of cell from the human body. Yamanaka and his colleagues made iPS cells by introducing into adult cells a cocktail of four genes (Oct4, Klf4, Sox2, and c-Myc). iPS cells, like embryonic stem cells, which are made from human embryos, are pluripotent, which means that they can differentiate into any mature adult cell type. iPS cells represent a promising medical advance, since they might be able to ultimately replace diseased organs with new organs that were derived from the patient’s own cells. Such technology will create tissues and organs that match the tissue types of the patient from whom the adult cells were isolated, which would eliminate all risks of transplantation rejection. The use of iPS cells would also circumvent the inherent ethical problems raised by the use of embryonic stem cells, which are derived from the destruction of human embryos.

Despite this success, cell reprogramming is besets by some problems. First of all, it is not terribly efficient; many cells undergo programmed cell death and this restricts the number of iPS cells produced. To increase the efficiencies of iPS cell production, Fabrice Lavial’s team, in collaboration with Patrick Mehlen’s team, identified new regulators of the derivation of iPS cells. They examined those genes that are regulated by the four inducing genes involved in the initiation of reprogramming. From this list of genes, they selected those genes known to have a role in programmed cell death, and whose expression varies over the course of reprogramming. This screening process yielded a gene that encodes a protein called netrin-1.

Netrin-1 is a protein naturally secreted by the body. Interestingly, netrin-1 can prevent programmed cell death, among other things. In the early days of reprogramming mouse cells, the researchers observed that their production of netrin-1 was strongly reduced, which limited the efficacy of the reprogramming process. Next, these research teams tested the effects of adding extra netrin-1 to cells during the early phases of reprogramming. This increased the quantity of iPS cells produced from mouse cells. When they repeated this experiment with human cells, the reprogramming process generated fifteen times more iPS cells than those produced by protocols without added netrin-1.

From a therapeutic point of view, it was important to determine whether this treatment affected the quality of cell reprogramming. Genomic tests, however, failed to show any deleterious effects of the use of netrin-1 on reprogrammed cells. “According to several verifications, netrin-1 treatment does not seem to have any impact on the genomic stability the iPS cells or on their ability to differentiate into other tissues,” says Fabrice Lavial, Inserm Research Fellow.

These research teams continue to test the effects of netrin-1 on the reprogramming of other types of cells. They would like to gain a better understanding of the mode of action of this molecule in stem cell physiology.

University of Iowa Team Creates Insulin-Producing Cells from Skin Cells


A research team from the University of Iowa has designed a protocol that can create insulin-producing cells that help normalize blood-sugar levels in diabetic mice from skin cells. This discovery represents one of the first steps toward developing patient-specific cell replacement therapy for Type 1 diabetes. This research, which was led by Nicholas Zavazava from the department of internal medicine, was published in the journal PLoS ONE.

Zavazava and his coworker used human skin cells taken from punch biopsies and reprogrammed them to into induced pluripotent stem cells. These induced pluripotent stem cells were then differentiated in culture into pancreatic insulin-producing beta cells.

In culture, Zavazava’s cell made insulin in response to increased concentrations, but when they were implanted into diabetic mice, these cells responded to glucose, secreted insulin and worked to lower the blood-sugar levels in the mice to normal or near-normal levels.

Mind you, these induced pluripotent stem cell-derived beta cells were not as effective as pancreatic cells in controlling blood sugar levels, according to Zavazava in a UI news release. However, Zavazava and his team views the cells’ response in mice as an “encouraging first step” toward the goal of generating effective insulin-producing cells that potentially could be used to not just treat but cure Type 1 diabetes in humans.

“This raises the possibility that we could treat patients with diabetes with their own cells,” Zavazava said. “That would be a major advance, which will accelerate treatment of diabetes.”

Zavazava is also a member of UI’s Fraternal Order of Eagles Diabetes Research Center. This center is one of several groups whose aim is to create an alternative source of insulin-producing cells that can replace the pancreatic beta cells that die off in people with Type 1 diabetes.

According to the UI news release, this study is the first to use human induced pluripotent stem cells instead of embryonic stem cells to generate insulin-producing pancreatic beta cells. This protocol has the advantage of creating beta cells from a patient’s own cells include. This would eliminate the need to wait for a donor pancreas, since pancreas transplants are an option for treating Type 1 diabetes, but the demand for transplants is much greater than the availability of organs from deceased donors. The use of induced pluripotent stem cells would also eliminate the need for transplant patients to take immunosuppressive drugs. Finally, the use of induced pluripotent stem cells would also avoid the ethical concerns with treatments based on embryonic stem cells.

Grafted Stem Cells Display Robust Growth in Spinal Cord Injury Model


University of San Diego neuroscientists have used an animal model of spinal cord injury to test the ability of engrafted stem cells to regenerate damaged nerves. Mark Tuszynski and his team built on earlier work with implanted neural stem cells and embryonic stem cell-derived neural stem cells in rodents that had suffered spinal cord injuries.

In this study, Tuszynski and others used induced pluripotent stem cells that were made from a 86-year-old male. This shows that skin cells, even from human patients who are rather elderly, have the ability to be reprogrammed into embryonic stem cell-like cells. These cells were differentiated into neural stem cells and then implanted into the spinal cords of spinal cord-injured rodents.

The injured spinal cord is a very hostile place for implanted cells. Inflammation in the spinal cord summons white blood cells to devour cell debris. White blood cells are rather messy eaters and they release enzymes and toxic molecules that can kill off nearby cells. Also, regenerating cells run into a barrier made by support cells called glial cells that inhibit regenerating neurons from regenerating. Thus, the injured spinal cord is quite the toxic waste dump.

To get over this, Tuszynski and his coworkers treated their induced pluripotent stem cell-derived neural stem cells with growth factors. In fact, when the cells were implanted into the animal spinal cords, they were embedded in a matrix that contained growth factors. After three months, Tuszynski and his colleagues observed extensive axonal growth projecting from grafted neurons that reached long distances in both directions along the spinal cord from the brain to the tail end of the spinal cord. These sprouted axons appeared to make connections with the existing rat neurons. Importantly, these axons extended from the site of the injury, which is astounding given that the injured area of the spinal cord has characteristics that are inimical to neuronal and axon growth.

Even though Tuszynski and others showed that neural stem cells made from embryonic stem cells can populate the damaged spinal cord, using induced pluripotent stem cell-derived neural stem cells has an inherent advantage since these cells are less likely to be rejected by the patient’s immune system. Furthermore, the induced pluripotent stem cell-derived neural stem cells showed dramatic growth in the damaged spinal cord, but the implanted animals did not regain the use of their forelimbs. The implanted human cells were fairly young when the implanted animals were tested. Therefore, they might need to mature before they could restore function to the implanted animals.

“There are several important considerations that future studies will address,” Tuszynski said. “These include whether the extensive number of human axons make correct or incorrect connections; whether the new connections contain the appropriate chemical neurotransmitters to form functional connections; whether connections once formed are permanent or transient; and exactly how long it takes human cells to become mature. These considerations will determine how viable a candidate these cells might before use in humans.”

Tuszynski and his group hope to identify the most promising neural stem cell type for repairing spinal cord injuries. Tuszynski emphasized their commitment to a careful, methodical approach:

“Ultimately, we can only translate our animal studies into reliable human treatments by testing different neural stem cell types, carefully analyzing the results, and improving the procedure. We are encouraged, but we continue to work hard to rationally to identify the optimal cell type and procedural methods that can be safely and effectively used for human clinical trials.”

Heart Muscle Cells Produced from Induced Pluripotent Stem Cells Repair Heart Attacks in Pigs


When heart muscle cells are made from embryonic stem cells, they integrate into the heart and form proper connections with other heart muscle cells. Such experiments have been conducted in mice, guinea pigs, and nonhuman primates (i.e. monkeys). Chong and others earlier this year (Nature (2014) 510, 273-277) implanted heart muscle cells produced from embryonic stem cells into the hearts of nonhuman primates that had suffered from heart attacks. There was extensive evidence of engraftment of these cells, remuscularization of the heart, and electrical synchronization 2 to 7 weeks after transplantation. However, despite these successes, the hearts of some of these animals also showed abnormal heart beat patterns (known as arrhythmias). Such a problem has also been observed in other laboratory animals as well (see my book The Stem Cell Epistles), and this problem has to be addressed before derivatives of pluripotent stem cells can be used to treat damaged hearts (pluripotent means capable of differentiating into all the mature adult cell types).

Jianyi Zhang and his colleagues at the University of Minnesota have used induced pluripotent stem cells made from human skin cells to produce heart muscle cells that were used to treat pigs that had suffered from induced heart attacks.  Their results differed slightly from those of Chong and others.

Zhang and others noted that implanted heart muscle cells typically survive better if they are implanted with blood vessel cells (endothelial cells or ECs).  This was first shown in culture by Xiong and others in 2012 (Circulation Research 111, 455-468), but other work has confirmed this.  That is, Zhang’s coworkers in his laboratory co-transplanted heart muscle cells made from induced pluripotent stem cells with endothelial cells and smooth muscle cells (which are also a part of blood vessels), and saw that the co-transplanted cells survived much better than heart muscle cells that were transplanted without these other cell types.

On the basis of these experiments, Zhang and his crew decided that implanted heart muscle cells would do much better if they were implanted into pig hearts if they were implanted with endothelial and smooth muscle cells.  This was the hypothesis that Zhang and others wanted to test in this paper (which was published in Cell Stem Cell, Dec 4, 2014, 750-761).

Skin biopsies from human volunteers were used as a source of skin cells that were then genetically engineered and then cultured to form human induced pluripotent stem cells (hiPSCs).  These cultured hiPSCs were differentiated into heart muscle cells by means of the “Sandwich method,” which yielded beating heart muscle cells in about 30 days.  Additionally, their hiPSC lines were differentiated into smooth muscle and endothelial cells as well.

Next, Zhang and his colleagues and collaborators used 92 pigs and subjected them to experimentally-induced heart attacks.  Why pigs?  Pigs are a larger animal than rodents, and their hearts are larger and beat much slower than the hearts of rats and mice.  Therefore, they are a more expensive, but better experimental model system for the human heart.  Nevertheless, these pigs were divided into six different groups (3 pigs died from the procedure, so there were 89 pigs involved in this experiment).  Animals in the first group or SHAM group underwent the surgery to induce a heart attack, but no heart attack was induced.  The second group was called the MI group and this group received no other interventions after surgery.  The Patch group received a fibrin patch over the site of injury, but no cells.  The CM + EC + SMC group received injections of 2 million heart muscle cells, two million endothelial cells, and two million smooth muscle cells directly into the injured portion of the heart.  The Cell + Patch group received all three cell types in a fibrin patched that was imbued with a growth factor called Insulin-like growth Factor-1 (IGF-1) that had been loaded into microspheres.  This causes the growth factor to be released gradually and exert its effects over a much greater period of time.

That’s a lot of information so let’s review – six groups: 1) SHAM (no heart attack; 2) MI (heart attack and no treatment); 3) Patch (just the fibrin patch); 4) Cells + Patch (fibrin patch with the three cell types); 5) Cells (cells, but no patch), and a final group cells Patch + CM (just heart muscle cells in the patch).

Animals were evaluated one week after the heart attack and four weeks after their heart attacks. I am uncertain how soon after the heart attack the treatments were given, but in the paper it reads to me as though the treatments were given right after the heart attacks had been induced.  Because all implanted cells were engineered to glow in the dark, the number of surviving cells could be counted and tracked.

Only 4.2% of the cell survived in the Cells group, up to 9% of the cells in the Cell + Patch group survived.  32% of the cells in the CM + Patch group survived.  Thus, it seemed as though the presence of the other cell types did increase the survival of the heart muscle cells and the patch also increased cell survival rates.  Secondly, the heart function of all the treated groups was better than the MI group, but the hearts treated with Cells + Patch were clearly superior to all the others, with the exception of the SHAM group.  The hiPSC-derived heart muscle cells also clearly engrafted into the hearts of the pigs, but the big surprise in this paper is that THERE WERE NO INDICATIONS OF ARRHYTHMIAS!!!  Apparently the manner in which these hiPSC-derived heart muscle cells integrated and adapted to the native heart in such as way as to preclude irregular electrical activity.  Another indicator measured was ratio of phosphocreatine to ATP.  If that sounds like a language from outer space, it simply means a measurement of the efficiency of muscle mitochondria (the part of the cell that makes all the energy).  Again the Cells + Patch hearts had significantly more efficient mitochondria, and, hence, better energy production than the other hearts.  Damage to mitochondria also tends cause cells to up and die, which means that these cells were in better health that those from the MI group.

This paper shows that an ingenious tissue engineering innovation that uses a fibrin patch and a a combination of cells, not just heart muscle cells can significantly increase the healing after a heart attack.  Also, even though neither embryonic stem cell-derived cells nor iPSC-derived cells are ready for clinical trials, this paper shows that iPSCs are not as far behind iPSCs as some authors have suggested.  Furthermore, because iPSCs would not be subject to immunological rejection, they have an inherent superiority over embryonic stem cells.  The problem comes with the time required to make iPSCs and then derived heart muscle cells from them, which might put it outside the time window for treat of an acute heart attack.

Embryonic Stem Cells From Cloned Embryos Vs Induced Pluripotent Stem Cells: Let the Debate Begin


In May of 2013, Shoukhrat Mitalipov and his coworkers from the Oregon Health and Science University, reported the derivation of human embryonic stem cells from cloned human embryos. Other stem cell scientists have confirmed that Mitalipov’s protocol works as well as he says it does.

Mitalipov and others have also examined the genetic integrity of embryonic stem cells made from cloned human embryos and induced pluripotent stem cells made from mature adult cells through genetic engineering and cell culture techniques. This paper was published in Nature in June 2014 and used genetically matched sets of human Embryonic Stem cells made from embryos donated from in vitro fertilization clinics, induced Pluripotent Stem cells and nuclear transfer ES cells (NT-ES cells) derived by somatic cell nuclear transfer (SCNT). All three of these sets of stem cells were subjected to genome-wide analyses. These analyses sowed that both NT-ES cells and iPS cells derived from the same somatic cells contained comparable numbers of genetic variations. However, DNA methylation, a form of DNA modification for regulatory purposes and gene expression profiles of NT-ES cells corresponded closely to those of IVF ES cells. However, the gene expression provide of iPS cells differed from these other two cell types and iPS cells also retained residual DNA methylation patterns typical of the parental somatic cells. From this study, Mitalipov stated that “human somatic cells can be faithfully reprogrammed to pluripotency by SCNT (that means cloning) and are therefore ideal for cell replacement therapies.”

Now a new study by Dieter Egli of the New York Stem Cell Foundation (NYSCF) in New York City, which included Mitalipov as a collaborator, has failed to demonstrate significant genetic differences between iPS cells and NT-ES cells. This is significant because Eglin has long been a rather vigorous proponent of cloning to make patient-specific stem cells. Egli gave an oral preview of his forthcoming paper on October 22nd, at the NYSCF annual conference. Egli told his audience, “This means that all of you who are working on iPS cells are probably working with cells that are actually very good. So I have good news for you,” he told them, eliciting murmurs and chuckles. “What this exactly means for the SCNT program, I don’t know yet.”

Egli and colleagues used skin cells from two people—a newborn and an adult—to create both stem cells from cloned embryos (using donor eggs) and iPS cells. Then they compared the genomes of these two types of cell lines with the genomes of the original skin cells in terms of genetic mutations, changes in gene expression, and differences in DNA methylation. Both methods resulted in about 10 mutations compared with the average genome of the mature source cells. These changes didn’t necessarily happen during reprogramming, however, Egli says, since many of these mutations were likely present in the original skin cells, and some could have arisen during the handling of cells before they were reprogrammed.

Both types of stem cells also carried a similar amount of methylation changes. Overall, the method didn’t seem to matter, Egli and his team concluded. Because he is a longtime proponent of SCNT, Egli says it would have been “more attractive” to reveal significant differences between the two kinds of stem cells. “This is simply not what we found.”

Now it would be premature to conclude that iPS cells are as good as NT-ES cells for regenerative purposes, but this certainly seems to throw a monkey wrench in the cloning bandwagon. Cloning would be quite complicated and expensive and also requires young, fertile women to donate their eggs. These egg donors must undergo potentially risky procedures to donate their eggs. Jennifer Lahl’s documentary Eggsploitation provides just a few of some of the horror stories that some women experienced donating their eggs. The long-term effects of this procedure is simply not known and asking young women to do this and potentially compromise their health or future fertility seems beyond the pale to me.

Alternatively, iPS technology keeps improving and may come to the clinic sooner than we think. Also, is a cloned embryo essentially different from one made through IVF or “the old-fashioned way.?” This whole things seems to me to involved the creation of very young human beings just so that we can dismember them and use them as spare parts. Such a practice is barbaric in the extreme.

For those who are interested, please see chapters 18 and 19 of my book The Stem Cell Epistles to read more about this important topic.

Embryonic Stem Cell-Derived Retinal Cells Treat Blindness in Eye Patients


Embryonic stem cells are derived from human embryos, can only grow in culture indefinitely, and have the ability to potentially differentiate into any adult cell type in the human body.  Because cell and tissues made from embryonic stem cells bear the same tissue types as the embryos from which they were derived, they will be rejected by the immune system patient.  However, there are sites in our bodies were the immune system does not go, and that includes the central nervous system and the eyes.  This is the reason why clinical trials with embryonic stem cell-derived cells have focused, to date, on spinal cord injuries and eye diseases.

Several clinical trials have examined the ability of retinal pigmented epithelial (RPE) cells made from embryonic stem cells to treat patients with dry macular degeneration or an inherited eye disease called Stargardt’s disease.  Data from these trials has been reported in an article in the medical journal The Lancet, and accordingly, none of the treated patients showed tumor formation or immunological rejection of the implants and, most impressively perhaps, partial blindness was reversed in about half of the eyes that received transplants.

The results might re-energize the quest to harness embryonic stem cells for human medicine.  Dr. Anthony Atala of the Wake Forest Institute for Regenerative Medicine called the work “a major accomplishment” in an accompanying commentary on the article.

RPE cells lie just behind the photoreceptor cells in the retina of our eyes.  Photoreceptors have their ends hurried in the RPE layer.  This arrangement exists for a very good reason; the photoreceptors are exposed to high intensities of light and they suffer respectable amounts of oxidative damage.  The components of the photoreceptors cells are made in the very lowest parts of the RPEs and then are eventually pushed to the ends of the cells.  At the end of the photoreceptor cells, the RPEs relieve the photoreceptors of their photodamaged parts and gobble them down, and recycle the cellular components.  Thus, RPE cells serve a photoreceptor cell repair and service cells.  If the RPE cells begin to die, the photoreceptors are not long the this work either.

In the case of dry macular degeneration, which accounts for 90 percent of diagnosed cases of macular degeneration, the light-sensitive photoreceptor cells of the macula (the portion of the retina were the day vision is the sharpest) slowly break down. Damage to the macula causes blurring or spotty loss of central vision and yellowish cellular deposits called drusen (extracellular waste products from metabolism) form under the retina between the retinal pigmented epithelium (RPE) layer and a basement membrane called Bruch’s membrane, that supports the retina. An increase in the size and number of drusen is associated with the death of RPE and, consequently, photoreceptor cells, and is sometimes the first sign of dry macular degeneration.

Medical illustration of dry macular degeneration

Mutations in several genes have been identified in families with dry macular degeneration that increase the risk for dry macular degeneration.  These include the SERPING1 gene, those genes that encode the complement system proteins  factor H (CFH), factor B (CFB) and factor 3, and fibulin-5.  Additionally, some environmental and behavioral factors also influence the risk a person will develop macular degeneration.  These include smoking, exposure to blue light, ingestion of a high-fat diet, elevated blood pressure and serum cholesterol levels, and low vitamin D levels.

Stargardt’s disease is an inherited, juvenile form of macular degeneration that is caused by mutations in the ABCR gene.  The protein encoded by this gene is a waste metabolite transporter, and defects in this protein cause the build up of a toxic metabolite called lipofuscin in the RPE cells, which leads to their demise and the death of the photoreceptors.

In this study, the main goal was to assess the safety of the transplanted cells. The study “provides the first evidence, in humans with any disease, of the long-term safety and possible biologic activity” of cells derived from embryos, said co-author Dr. Robert Lanza, chief scientific officer of Advanced Cell Technology, which produced the cells and funded the study.

Nine patients with Stargardt’s disease and nine with dry age-related macular degeneration received implants of the retinal cells in one eye. The other eye served as a control.  Four eyes developed cataracts and two became inflamed, probably due to the patients’ age (median: 77) or the use of immune-supressing transplant drugs.

The implanted RPE cells survived in all 18 patients, most of whose vision improved.  In those with macular degeneration, treated eyes saw a median of 14 additional letters on a standard eye chart a year after receiving the cells, with one patient gaining 19 letters. The untreated eyes got worse, overall. The Stargardt’s patients had similar results.

In real-life terms, patients who couldn’t see objects under 12 feet (4 meters) tall can now see normal-size adults.

The vision of one 75-year old rancher who was blind in the treated eye (20/400) improved to 20/40, enough to ride horses again, Lanza said.  Others became able to use computers, read watches, go to the mall or travel to the airport alone for the first time in years.

While calling the results “encouraging,” stem cell expert Dusko Ilic of Kings College London, who was not involved in the work, warned that even if the larger clinical trial planned for later this year is also successful, “it will take years before the treatment becomes available.”

Other cell types can also form RPE cells and these include induced pluripotent stem cells, mesenchymal stem cells from fat (Ophthalmic Res. 2012;48 Suppl 1:1-5), adult retinal stem cells (Pigment Cell Melanoma Res. 2011 Feb;24(1):233-40), and iris pigmented epithelial cells (Prog Retin Eye Res. 2007 May;26(3):302-21).  We do not need to destroy embryos to treat eye diseases with stem cells.

Nerve Growth Factor-Secreting Mesenchymal Stem Cells To Treat Huntington’s Disease


Vicki Wheelock at the UC Davis Medical Center has registered clinical trial number NCT01937923, which is otherwise known as “PRE-CELL.” This clinical trial will use various imaging techniques, laboratory tests, and clinical evaluations of Huntington’s disease (HD) patients to map the disease progression over 12-18 months. This trial will then hopefully identify candidates for a new trial in which these patients will be implanted with mesenchymal stem cells that secrete nerve growth factors. This represents one of the first clinical trials to examine the use of mesenchymal stem cells in the treatment of HD

The rationale for this study comes from a 2012 study in mice. Ofer Sadan, Eldad Melamed, and Daniel Offen from the Rabin Medical Center in Tel Aviv University, Israel, used R6/2 mice to test the efficacy of nerve growth factor-secreting mesenchymal stem cells isolated from bone marrow . In this paper, Sadan and others isolated mesenchymal stem cells from the bone marrow of healthy human volunteers and mice and then cultured them in special growth media that induces these cells to secrete special nerve growth factors. These so-called NTF+ cells were then transplanted into the striatum of R6/2 mice.

R6/2 mice express part of the human HTT gene; specifically the part that causes HD. Since HD is an inherited disease, there is a specific gene responsible for the vast majority of HD cases, and that gene is the human HTT gene, which encodes the Huntington protein. The function of the Huntington protein is uncertain, but it is found at high levels in neurons, even though it is found in other tissues as well, and dysfunctional Huntington protein affects neuron health.

Huntingtin Function

The HTT gene in HD patients contains the insertion of extra copies of the CAG triplet. The more CAG triplets are inserted into the HTT gene, the more severe the HD caused by the mutation. The hitch is that normal copies of the HTT gene has multiple copies of this CAG repeat. CAG encodes the amino acid glutamine, and Huntington contains a stretch of glutamine residues that seem to allow the protein to interact with other proteins found in neurons. When this glutamine stretch becomes too long, the protein is toxic and it begins to kill the cells. How long is too long? Research has pretty clearly shown that people whose HTT genes contain less than 28 CAG virtually never develop HD. People with between 28–35 CAG repeats, are usually unaffected, but their children are at increased risk of developing HD. People whose HTT genes contain 36–40 CAG repeats may or may not show HD symptoms, and those who have over 40 copies almost always are afflicted with HD.

hunt_gene_big

Now, back to R6/2 mice. These animals contain a part of the human HTT gene that has 150 CAG triplets. These mice show the characteristic cell death in the striatum and have behavioral deficits. In short R6/2 mice are pretty good model systems to study HD.

Sadan and others implanted MSCs that had been conditioned in culture to express high levels of nerve growth factors. Then these cells were transplanted into the striatum of R6/2 mice. R6/2 mice were also injected with buffer as a control.

The results showed that injections of NTF+ MSCs before the onset of symptoms did little good. The mice still showed cell death in the brains and behavioral deficits. However, NTF+ MSCs injected later (6.5 weeks), resulted in temporary improvement in the ability of the R6/2 mice to move and these cells also extended their life span. These results were published in the journal PLoS Currents (2012 Jul 10;4:e4f7f6dc013d4e).

Other work, also by Sadan and others, showed that injected MSCs tended to migrate to the damaged areas. When the injected cells were labeled with iron particles, they could be robustly observed with MRIs, and MRIs clearly showed that the injected cells migrated to the damaged areas in the brain (Stem Cells 2008; 26(10):2542-51). Another paper by Sadan and others also demonstrated that the striatum of NTF+ MSC-injected mice show less cell death than control mice (Sadan, et al. Exp Neurol. 2012; 234(2): 417-27). Other workers have also shown that implanted MSCs can provide improve symptoms in R6/2 mice and that they primary means by which they do this is by the secretion of nerve growth factors (Lee ST, et al. Ann Neurol 2009; 66(5): 671-81).

Thus, there is ample reason to suspect the PRECELL trial may lead to a stem cell-based clinical trial that will yield valuable clinical information. The animal data shows definite value in using preconditioned MSCs as a treatment for HD, and if the proper patients are identified by the PRE-CELL trials, then hopefully it will lead to a “CELL” trial in which HD patients are treated with NTF+ MSCs.

Mind you, this treatment will only delay HD at best and buy them time. Such treatments will not cure them. The NTF+ MSCs survive for a finite period of time in the hostile environment of the striatum of the HD patient, and the relief they will provide will be temporary. MSCs do not differentiate into neurons in this case, and they do not replace dead neurons, but they only help spare living neurons from suffering the same fate.

Huntington disease striatum

There is an MSC cell line that does make neurons, and if this cell line were used in combination with NTF+ MSCs, then perhaps neural replacement could be a possibility.  Also neural precursor cells could be used in combination with NTF+ MSCs to increase their survival.  Even then, as long as diseased neurons are producing toxic products, until gene therapy is perfected to the point that the actual genetic lesion in the striatal neurons is fixed, the deterioration of the striatum is inevitable. However, treatments like this could, potentially, delay this deterioration. This clinical trial should give us more information on exactly that question.

Two more points are worth mentioning.  When fetal striatal grafts were implanted into the brains of HD patients, the grafts underwent disease-like degeneration, and actually made the patients worse (see Cicchetti et al. PNAS 2009; 106(30): 12483-8 and Cicchetti F, et al. Brain 2011; 134(pt 3): 641-52).  Straight fetal implants do not seem to work.  Please let’s put the kibosh on these gruesome experiments.  Secondly, when neuronal precursor cells differentiated from human embryonic stem cells were implanted into HD rodents, the implanted cells formed some neurons and improved behavior to some extent, but non-neuronal differentiation remained a problem (Song J, et al., Neurosci Lett 2007; 423(1): 58-61).  Having non-brain cells in your brain is a significant safety problem.  Thus, embryonic stem cell-derived neuronal precursor cells do not seem to be the best bet to date either.  So, this present clinical trial seems to be making the most of what is presently safely available.

The First Patient Treated with iPSC-Derived Cells


Nature News has reported that a Japanese patient was received the first treatment derived from induced pluripotent stem cells.

Ophthalmologist Masayo Takahashi from the Riken Center for Developmental Biology and her team used genetic engineering techniques to reprogram skin fibroblasts from this patient into induced pluripotent stem cells. These cultured iPSCs were then differentiated into retinal pigment epithelium cells. Takahashi’s colleagues, led by Yasuo Kurimoto at Kobe City Medical Center General Hospital, then implanted those retinal pigment epithelium cells into the retina of this female patient, who suffers from age-related macular degeneration.

It is unlikely that this procedure will restore the woman’s vision. However, because age-related macular degeneration is a progressive process, Takahashi and her research team will be examining if this procedure prevents further deterioration of her sight. Takahashi’s Riken team has extensively tested this procedure in laboratory animals and recently received human trial clearance. Takahashi’s team will also be looking particularly hard at the side effects of this procedure; such as immune reaction or cancerous growth.

“We’ve taken a momentous first step toward regenerative medicine using iPS cells,” Takahashi says in a statement, according to Nature News. “With this as a starting point, I definitely want to bring [iPS cell-based regenerative medicine] to as many people as possible.”

Mesenchymal Stem Cells Derived from Induced Pluripotent Stem Cells are Epigenetically Rejuvenated


Earlier this year, Miltalipov and his research group published a paper in Nature that compared the genetic integrity of embryonic stem cells made from embryos, to induced pluripotent stem cells and embryonic stem cells made from cloned embryos.  All three sets of stem cells seemed to have comparable numbers of mutations, but the induced pluripotent stem cells had “epigenetic changes” that were not found in either stem cell line from cloned or non-cloned embryos.

Genetic characteristics have to do with the sequence of the DNA molecules that make up the genome of an organism.  Epigenetic characteristics have nothing to do with the sequence of DNA, but instead are the result of small chemicals that are attached to the DNA molecule.  These small chemical tags affect gene expression patterns.  Every cell has a specific epigenetic signature.

During development, the cells that will form our eggs and sperm in our bodies, the “primordial germ cells,” begin their lives in the outer layer of the embryo.  During the third week of life, these primordial germ cells or PGCs move like amoebas and wander into the yolk sac wall and collect near the exit of a sac called the “allantois.”  The PGCs are outside the embryo at this time or extraembryonal.  Incidentallyyolk sac is a terrible name for this structure, since it does not produce yolk proteins.  Therefore other textbooks have renamed it the “primary umbilical vesicle,” which is a bit of a mouthful, but it probably better than “yolk sac.”

 

1 - Primordial germ cells 2 - Allantois 3 - Rectum 4 - Ectoderm 5 - Foregut 6 - Primordial Heart 7 - Secondary yolk sac 8 - Endoderm 9 - Mesoderm 10 - Amniotic cavity
1 – Primordial germ cells
2 – Allantois
3 – Rectum
4 – Ectoderm
5 – Foregut
6 – Primordial Heart
7 – Secondary yolk sac
8 – Endoderm
9 – Mesoderm
10 – Amniotic cavity

The embryo around this time undergoes a bending process as a result of its growth and the head bends toward the tail (known as the cranio-caudal curvature) and then the sides of the embryo fold downwards and eventually fuse (lateral folding).  This bending of the embryo allows the PGCs to wander back into the embryo again between the fourth and sixth week.  The PGCs move along the yolk sac wall to the vitelline and into the wall of the rectum.  After crossing the dorsal mesentery (which holds the developing intestines in place) they colonize the gonadal or genital ridge (which is the developing gonad). During their journey, and while in the gonadal ridge, the PGCs divide many times.

1 - Rectum 2 - Vitelline 3 - Allantois 4 - Nephrogenic cord (pink) 5 - Gonadal ridge (green) 6 - Primordial germ cells (red dots) 7 - Heart prominence
1 – Rectum
2 – Vitelline
3 – Allantois
4 – Nephrogenic cord (pink)
5 – Gonadal ridge (green)
6 – Primordial germ cells (red dots)
7 – Heart prominence

When the PGCs move into the developing gonad, the chemical tags on their DNA are completely removed (rather famous paper – Lee, et al., Development 129, 1807–1817 (2002).  This epigenetic erasure proceeds in order for the PGCs to develop into gametes and then received a gamete-specific set of epigenetic modifications.  These epigenetic modifications also extend to the proteins that package the DNA into chromosomes – proteins called histones.  Specific modifications of histone proteins and DNA lead to gamete-specific expression of genes.  Once fertilization occurs, and the embryological program is initiated, tissue-specific epigenetic modifications are conveyed onto the DNA and histones of particular cell populations.

This is a long-winded explanation, but because many cancer cells have abnormal epigenetic modifications, these epigenetic abnormalities in induced pluripotent stem cells (iPSCs) have been taken with some degree of seriousness.  Although, there is little evidence to date that links the cancer-causing capabilities of iPSCs with specific epigenetic modifications, although it certainly affects the ability of these cells to differentiate into various cell types.

A paper has just come from the laboratory of Wolfgang Wagner from the Aachen University Medical School, in Aachen, Germany that derived iPSCs from mesenchymal stem cells from human bone marrow, and then in a cool one-step procedure, differentiated these cells into mesenchymal stem cells (MSCs).  These  iPS-MSCs looked the same, and acted the same in cell culture as the parent MSCs, and had the same gene expression profiles as primary MSCs.  However, all age-related and tissue-specific epigenetic patterns had been erased by the reprogramming process.  This means that all the tissue-specific, senescence-associated, and age-related epigenetic patterns were erased during reprogramming.  Another feature of these iPS-MSCs is that they lacked but the ability to down-regulate the immune response, which is a major feature of MSCs.

Thus, this paper by the Wagner lab shows that MSCs derived from iPSCs are rejuvenated by the reprogramming process.  Also, the donor-specific epigenetic features are maintained, which was also discovered by Shao and others last year.  This suggests that epigenetic abnormalities are not an inherent property of the derivation of iPSCs, and that this feature is not an intractable characteristic of iPSCs derivation and may not prevent these cells from being successfully and safely used in the clinic.  However, this might be a cell type-specific phenomenon.  Also, the loss of the immune system regulatory capabilities of these iPS-MSCs is troubling and this requires further work.

iPS-MSCs

Chicken Induced Plurpotent Stem Cells Made With Minicircles


The safety of induced pluripotent stem cells (iPSCs) haws been debated in several studies and publications.  Original studies of the genetic differences between the cellular sources of iPSCs and the iPSCs derived from them tended to show a whole gaggle of new mutations that seemed to not appear in the original cells.  Therefore, several commentators warned about the “dark side of pluripotency.”. However, other studies that utilized higher-resolution techniques showers that many of these mutations that occurred in iPSCs did exist in the original cells before their reprogramming, but that these mutations occurred at low frequencies, but became amplified during the culturing of reprogrammed cells.

One feature that has received less attention in these discussions of the safety of iPSC derivation is that the method by which iPSCs are made has distinct consequences for the stem cells that are made.  Typically, methods that utilize gene vectors that do not integrate into the genomes of the host cells are inherently safer than those vectors that do integrate.  PiggyBac transposon vectors integrate, but self-excise soon after their integration, and, therefore, do not leave a trace or their previous integration.  Minicircles also do not integrate and tend to produce safer iPSCs.  For this reason, this present paper is of interest to us.

Franklin West and his colleagues at the University of Georgia have made chicken iPSCs using minicircles to reprogram adult cells.  West was interested in using iPSCs to make recombinant chickens, since chickens are a rather primary food source and major component of economic development in several countries.  Making transgenic or recombinant chickens by means of stem cell technology makes it possible to make animals with improved meat and egg production or disease resistance.

To this end, West and his group made chicken (c) iPSCs from skin fibroblast cells by means of a nonviral minicircle reprogramming method.  This resulted in ciPSCs that showed excellent stem cell appearance and expressed key stem cell marker genes (alkaline phosphatase, POU5F1, SOX2, NANOG, and SSEA-1).  These cells also showed very rapid growth in culture and expressed high levels of the enzyme telomerase, which is an enzyme that is vital for the maintenance of chromosomes.

When West and his research group transplanted late-passage ciPSCs into stage X chicken embryos, the cIPSCs successfully integrated into the growing embryo and contributed to tissues derived from all three primary germ layers (ectoderm, mesoderm, and endoderm).  These ciPSCs also contributed to the gonads, which means that the ciPSCs could make gametes that could contribute to the production of a new generation of chicken.

These ciPSCs provide an exciting new tool to create transgenic chickens and has broad and exciting implications for agricultural and transgenic animal fields at large.  However, it also demonstrates that iPSCs can be safely produced and used for agricultural purposes.  This means that if non-integration-based or non-viral-based techniques are used to make iPSCs it should be possible to make them safely for therapeutic purposes also.

Human Stem Cell-Derived Neurons Grow New Axons In Spinal Cord Injured Rats


A stem cell-based treatment for spinal cord injury took one more baby step forward when scientists from the laboratory of Mark Tuszynski at the at the University of California, San Diego used cells derived from an elderly man’s skin to regrow neural connections in rats with damaged spinal cords.

Tuszynski and others published their results in the Aug. 7 online issue of the journal Neuron. In that paper, Tuszynski and his co-worker report that human stem cells triggered the growth of numerous axons in the damaged spinal cord. Axons are those fibers that extend from the main part or body a neuron (nerve cell) that serve to send electrical impulses away from the body to other cells. Some of these new axons even grew into the animals’ brains.

Axon picture

Dr. Mark Tuszynski is a professor of neurosciences at the University of California, San Diego. “This degree of growth in axons has not been appreciated before,” he said. However, Tuszynski also cautioned that there is still much to be learned about how these newly established nerve fibers behave in laboratory animals. He likened the potential for stem-cell-induced axon growth to nuclear fusion. If it’s contained, you get energy; if it’s not contained, you get an explosion. “Too much axon growth into the wrong places would be a bad thing,” Tuszynski added.

Stem cell researchers have examined the potential for stem cells to restore functioning nerve connections in people with spinal cord injuries. Embryonic stem cells have been used to make new neurons and to also make “oligodendrocyte progenitor cells” or OPCs, which make the insulating myelin sheath that enwraps the axons of spinal nerves. However, several other types of stem cells can make OPCs and new neurons and these stem cells do not come from embryos (for more, see chapter 27 of my book, The Stem Cell Epistles).

In this study, Tuszynski and his team used induced pluripotent stem cells or iPSCs, which are derived from mature adult cells by means of genetic engineering and cell culture techniques. They used cells from a healthy 86-year-old man and genetically reprogrammed so that they were reprogrammed into iPSCs. These iPSCs were then differentiated into neurons that were implanted into a special scaffold embedded with proteins called growth factors, and then grafted into the spinal cords of laboratory rats with spinal cord injuries.

Over the course of several months, these animals showed new, mature neurons and extensive growth in the cells’ axons. These fibers grew through the injury-related scar tissue in the animals’ spinal cords and connected with resident rat neurons.

This is an enormous advance, because the wounded spinal cord creates a “Glial scar” that contains a host of molecules that repel growing axons. Even though this glial scar prevents the immune system from leaking into the spinal cord and destroying it, this same scar prevents the regeneration of damaged neurons and their severed axons.

Glial scar axon repulsion

Dr. David Langer, director of neurosurgery at Lenox Hill Hospital in New York City said: “One of the big obstacles [in this type of research] is this area of scarring in the spinal cord. Getting neurons to traverse it is a real challenge,” said Langer, who was not involved in the research. “The beauty of this study,” he said, “is that they got the neurons to survive and traverse the scar.”

Langer also cautioned, much like Tuszynski, that this experimental success is just a preliminary step. There are, in his words, “huge questions” as to whether or not these axons can make appropriate connections and actually restore function to spine-damaged lab animals. “It’s not just a matter of having the cables,” Langer said. “The wiring has to work.”

And even if this stem cell approach does pan out in animals, Langer added, it would all have to be translated to humans. “We have a long way to go until we’re there,” he said. “It’s not that people shouldn’t have hope. But it should be a realistic hope.”

A few biotech companies have already launched early-stage clinical trials using embryonic (Geron) or fetal stem cells (StemCells Inc) to treat patients with spinal cord injuries. But Tuszynski said his team’s findings offer a cautionary note about moving to human trials too quickly. “We still have a lot to learn,” he said. “We want to be very sure these axons don’t make inappropriate connections. And we need to see if the new connections formed by these axons are stable.”

Ideally, Tuszynski added, if stem cells were to be used in treating spinal cord injuries, they’d be generated as they were in this study — by creating them from a patient’s own cells. That way, he explained, patients would not need immune-suppressing drugs afterward.

Neurons Made from Induced Pluripotent Stem Cells Stably Integrate into the Brain


Jens Schwamborn and Kathrin Hemmer from the Luxembourg Centre for Systems Biomedicine (LCSB) of the University of Luxembourg have shown that implanted neurons made from induced pluripotent stem cells show long-term stability in the brain.

Induced pluripotent stem cells (iPSCs) are made from mature adult cells by means of genetic engineering and cell culture techniques. These cells have embryonic stem cell-like capacities and can, potentially differentiate into any adult cell type. Because neurons made from iPSCs have sometimes not shown instability, the ability of neurons derived from iPSCs to stably integrate into brain has been questioned.

Schwamborn and Hemmer showed that six months after implantation, their iPSCs-derived neurons had become fully functionally integrated into the brain. This successful integration of iPSC-derived neurons into lastingly stable implants raises hope for future therapies that will replace sick neurons with healthy ones in the brains of patients with Parkinson’s disease, Alzheimer’s disease and Huntington’s chorea, for example. This work was published in the current issue of Stem Cell Reports.

The LCSB research group hopes to bring cell replacement therapy to maturity as a treatment for neurodegenerative diseases. The replacement of sick and/or dead neurons in the brain could one day cure disorders such as Parkinson’s disease. However, devising a successful therapy in human is a long, arduous process, and for good reasons. “Successes in human therapy are still a long way off, but I am sure successful cell replacement therapies will exist in future. Our research results have taken us a step further in this direction,” declared Schwamborn.

In their latest tests, the LCSB research group, in collaboration with colleagues from the Max Planck Institute and the University Hospital Münster and the University of Bielefeld, made stable neuronal implants in the brain from neurons that were derived from reprogrammed skin cells. They used a newer technique in which the neurons were produced from neural stem cells (NSCs). These NSCs or induced neural stem cells (iNSCs) had, in turn been made from iPSCs that were made from the host animal’s own skin cells, which considerably improves the compatibility of the implanted cells. Mice who received the neuronal implants showed no adverse side effects even six months after implantation. The new neurons were implanted into the hippocampus and cortex regions of the brain. Implanted neurons were fully integrated into the complex network of the brain and they exhibited normal activity and were connected to the original brain cells via newly formed connections known as synapses, which are the contact points between nerve cells.

These tests demonstrate that stem cells researchers are continuing to get a better handle on how to use cells derived from something other than human embryos in order to successfully replace damaged or dead tissue. “Building upon the current insights, we will now be looking specifically at the type of neurons that die off in the brain of Parkinson’s patients – namely the dopamine-producing neurons,” Schwamborn reports.

In future experiments, implanted neurons could provide the neurotransmitter dopamine (which is lacking in patients with Parkinson’s disease) directly into the patient’s brain and transport it to the appropriate sites. Such a result would herald an actual cure for the disease rather than a short-term fix. The first trials in mice are in progress at the LCSB laboratories on the university campus Belval.

Making Better Induced Pluripotent Stem Cells


On July 2nd of this year, a paper appeared in the journal Nature that performed complete genomic analyses of embryonic stem cells derived from embryos or cloned embryos, and induced pluripotent stem cells (iPSCs), which are made from reprogrammed adult cells.  They found that both embryonic stem cells made from cloned embryos and iPSCs derived from the same types of adult cells contained comparable numbers of newly introduced mutations.  However, when it came to the epigenetic modification of the genome (the small chemical tags attached to specific bases of DNA that gives the cell hints as to which genes to turn off), the epigenetic pattern of the embryonic stem cells made from cloned embryos more closely resembled that from embryonic stem cells.  The iPSCs still had some similarities with the adult cells from which they were derived whereas the embryonic stem cells made from cloned embryos were more completely reprogrammed.  From this the authors claimed that making embryonic stem cells by means of cloning is ideal for cell replacement therapies.

There is a big problem with this conclusion:  This was tried in animals and it did not work because of immunological rejection of the products from the stem cells.  For more information on this, see my book, The Stem Cell Epistles, chapter 18.

Despite this “bad news” for iPSCs, two recent papers have actually provided some good news for stem cells that can heal without destroying embryos.  The first paper comes from Timothy Nelson’s laboratory at the Mayo Clinic in Rochester, Minnesota.  Differentiation of iPSCs is, in some cases, rather efficient and the isolation procedures fail to effectively isolate the differentiated cells from potentially tumor-causing cells.  However, in other cases, the differentiation is inefficient and the isolation procedures are also rather poor, which leaves a large enough population of undifferentiated tumor-causing cells.

Nelson’ group has discovered that treating iPSCs and their derivatives with anti-cancer drugs like etoposide (a topoisomerase II inhibitor for those who are interested) increases engraftment efficiency and decreases the incidence of tumors.  My only problem with Nelson’s paper is that he and his colleagues used lentiviral vectors to make their iPSCs.  These vectors tend to produce iPSCs that are rather good at causing tumors.  I would have rather that he tried making iPSCs with other methods that do not leave permanent transgenes in the cells.  Nelson and his group transplanted their iPSC-derived cells into the hearts of mice where they could use high-resolution imaging to determine the number of cells that integrated into the heart and the presence of cell masses that were indicative of tumors.  None of the ectoposide-treated cell transplants caused tumors whereas 4 of the 5 transplants not treated with ectoposide caused tumors.  This paper appeared in Stem Cells and Development.

The second “good news” paper for iPSCs comes from Junji Takeda at the University of Osaka and Ken Igawa from the Tokyo Medical and Dental University, Japan.   In their paper from Stem Cells Translational Medicine, the Japanese groups collaborated to make iPSCs from skin based fibroblasts and then differentiate them into skin cells (keratinocytes).  However, they made the iPSCs in two different ways.  The first protocol utilized the piggyBac transposon system to make iPSCs.  The piggyBac system comes from moths, but it is highly active in mammalian cells.  It can deliver the genes to the cells, but the segment of DNA is then easily excised from the host cells without causing any mutations.  This system, therefore, will generate iPSCs that do not have any transgenes in them.  The second protocol used a system based on cytomegalovirus that leaves the transgenes in the cells but gradually inactivates their expression.

When these two types of iPSCs were compared, they seems to be essentially identical when grown in culture.  Thus in the pluripotent state, the cells were equivalent for the most part.  But once the iPSC lines were differentiated into skin cells, the transgene-free iPSCs formed skin cells that looked, behaved and had the same gene expression profile as normal human skin cells.  The transgene-containing iPSCs differentiated into skin cells, but they did not look quite like skin cells, did not have the same gene expression profile as normal human skin cells, and did not behave like normal human skin cells.

The moral of this story is that not all iPSC lines are created equally and the way you derive them is as important as the cell type from which they were derived.  Also, even incomplete differentiation does not need to be an obstacle for iPSCs, since the cancer-causing cells can be removed by means of specific drugs.  Finally, not all that glitters is gold.  Cloned embryos may give you stem cells that look more like embryonic stem cells, but so what.  These might still suffer from many of the same set backs.  Add to that the ethical problems with getting women to give up their eggs for research and cures (see Jennifer Lahl’s movie Eggsploitation for more disturbing information about that), and you have a losing combination.

StemCells, Inc., Sued by Former Employee Who Says Their Stem Cell Treatment is Unsafe


A California stem cell company, StemCells, Inc., that is developing cell-based therapies for several different neurological and eye conditions, is being sued by a former employee (whistleblower) who claims that the company did not follow proper protocols in the preparation of their treatments. Rob Williams, who was once a senior manager at StemCells, Inc., has alleged that the company fired him after he brought these problems to the attention of senior management.

According to the Courthouse New Service, Williams in the lawsuit stated that he “noted poor sterile technique, failure to adhere to current Good Manufacturing Practices in the company’s manufacturing process, and substantial deficiencies in the company’s Manual Aseptic Processing of HuCNS-SC (Human Central Nervous System Stem Cells) cell lines—failure and deficiencies that put patients at risk of infection or death during ongoing clinical trials.”

Ken Stratton, who serves as the general counsel for StemCells, Inc., has told the California Stem Cell Report that Williams’s employment “was terminated for performance deficiencies, and [the company] finds no merit to the allegations.” Stratton also said that “the elements of manufacturing practices that concerned Mr. Williams were immediately and carefully reviewed by the company.”

It might be worth noting that this lawsuit coincides with the departure this past April or May of StemCells, Inc.’s Executive VP of Manufacturing Operations and Regulatory Affairs, Stewart Craig, who took a position at Sangamo Biosciences.

Unfortunately for StemCells, Inc., this particular lawsuit comes soon after a second bit of bad press. Embryologist Alan Trounson led the California Institute for Regenerative Medicine (CIRM) until June of this year, but has joined the board of StemCells, Inc., shortly after leaving the state stem cell research funding agency. According to an opinion article written by Ron Leuty, who is a reporter for the San Francisco Business Times, Trounson has recused himself from discussions regarding a loan StemCells, Inc., received from CIRM in 2012 because of his close relationship with the company’s founder. “But the speed of his appointment to the StemCells board has raised questions” about a possible conflict of interest, Leuty wrote.

CIRM has been marred by conflicts of interest accusations since California voters in 2004 birthed CIRM through Proposition 71 and the subsequent sale of $3 billion in state bonds. Now it has one more strike against it.

Leuty called the situation an embarrassment for CIRM. “If the public perceives that individuals—researchers or CIRM employees or company executives—are feeding at the trough of the semiautonomous public agency, it isn’t going to help CIRM get more cash from that very same public that foots the bill.”

Induced Pluripotent Stem Cells Used to Make New Bone In Monkeys


Cynthia Dunbar, MD and her colleagues at the National Heart, Lung, and Blood Institute, which is a division of the National Institutes of Health (NIH) in Bethesda, Maryland have shown for the first time that it is possible to make new bone from induced pluripotent stem cells that are derived from a patient’s own skin cells.

This study, which was done in monkeys, shows that there is some risk that induced pluripotent stem cells (iPSCs) can form tumors, but that the risk of tumor formation is less than what was shown in immuno-compromised mice.

iPSCs are made from adult cells by means of a process called “reprogramming.” To reprogram adult cells, genetic engineering techniques are used to introduce specific genes into adult cells. These introduced genes drive the adult cells to de-differentiate into a less mature state, until they eventually become pluripotent, much like embryonic stem cells.

Originally, discovered by Nobel-prize winner Shinya Yamanaka, reprogramming was initially done with genetically engineered viruses that insert genes into the genome of cells. Even though these viruses do a passable job of reprogramming cells, they also introduce insertion mutations. Yamanaka and others originally used four transcription factors (Oct4, Sox2, Klf4, c-Myc) to reprogram adult cells. Several of these genes are overexpressed in a variety of tumors, and therefore, the use of these genes does create a risk of forming cells that overgrown and become tumorous. Secondly, The reprogramming process does put cells under the types of stresses that increase the mutation rate, and these mutations can also increase the risk of forming tumor cells. However, it is clear that not all reprogramming protocols cause the same rate of mutations, and that the mutation rate of iPSCs was originally overestimated. What is required is a good way to screen iPSC lines for mutations and for safety, especially since not all iPSC lines are equal when it comes to their safety.

The advantage of using iPSCs over embryonic stem cells is that the immune system of the patient should not reject tissues and cells made from iPSCs. This would eliminate the need for immune suppression drugs, which can be rather toxic.

Cynthis Dunbar from the National Heart, Lung, and Blood Institute said of her experiments, “We have been able to design an animal model for testing of pluripotent stem cell therapies using the rhesus macaque, a small monkey that is readily available and has been validated as being closely related physiologically to humans.

Dr. Dunbar continued: “We have used this model to demonstrate that tumor formation of a type called a ‘teratoma’ from undifferentiated autologous iPSCs does occur; however, tumor formation is very slow and requires large numbers of iPSCs given under very hospitable conditions. We have also shown that new bone can be produced from autologous iPSCs as a model for their possible clinical application.”

Dunbar and her team used a excisable polycistronic lentiviral vector called STEMCCA (Sommer et al., 2010) that expressed four genes: human OCT4, SOX2, MYC, and KLF4 to make iPSCs from skin cells. After they had derived culturable iPSCs from rhesus monkeys (made under feeder-free conditions), Dunbar and her group seeded them on ceramic scaffolds that are used by reconstructive surgeons to fill in or rebuild bone. Interestingly, these cells regrew bone in the monkeys.

The differentiated iPSCs formed no teratomas, but monkeys that had received implantations of undifferentiated iPSCs formed teratomas in a dose-specific manner.

Dunbar and her colleagues note that this approach might be beneficial for people with large congenital bone defects or other types of traumatic injuries. Having said that, it is doubtful that bone replacement therapies will be the first human iPSC-based treatment, since bone defects are not life-threatening, even though they can seriously compromise the quality of a patient’s life.

“A large animal preclinical model for the development of pluripotent or other high-risk/high-reward generative cell therapies is absolutely issues of tissue integration of homing, risk of tumor formation, and immunogenicity,” said Dunbar. “The testing of human-derived cells in vitro or in profoundly immunodeficient mice simply cannot model these crucial preclinical safety and efficiency issues.”

This NIH team is now collaborating with other labs to differentiate macaque iPSCs into liver, heart, and white blood cells for to test them for eventual pre-clinical trials in hepatitis C, heart failure, and chronic granulomatous disease, respectively.

Differentiation of Induced Pluripotent Stem Cells Decreases Immune Response Against Them


The goal of regenerative medicine is to replace dead or damaged cells, tissues and even organs with living, properly functioning cells tissues and organs. However, this goal has a few genuine barriers that include tumor formation in the case of pluripotent stem cells, poor cell survival, or even immunological rejection of the transplanted cells before they can render any long-term benefits. Induced pluripotent stem cells (iPSCs), which are made from adult cells by a combination of genetic engineering and cell culture techniques, can be made from a patient’s own mature cells and the differentiated into almost any tissue in the adult body. However, research with mouse iPSCs has shown that even stem cells produced from the subject’s own tissues can be rejected by the subject’s own immune system.

Immune rejection of iPSCs is a legitimate concern, but research from the Stanford University School of Medicine has shown that differentiation of iPSCs into more mature cells before transplantation into mice allows them to be tolerated by the immune system.

Joseph Wu, MD, PhD, director of the Stanford Cardiovascular Institute, said, “Induced pluripotent stem cells have tremendous potential as a source for personalized cellular therapeutics for organ repair. This study shows that undifferentiated iPS cells are rejected by the immune system upon transplantation in the same recipient, but that fully differentiating these cells allows for acceptance and tolerance by the immune system without the need for immunosuppression.”

Wu is the senior author of this publication, which appeared online on May 30th in Nature Communications. Lead authorship of this paper is shared by Patricia Almeida, PhD, and Nigel Kooreman, MD, and assistant professor of medicine Everett Meyer, MD, PhD.

Several other studies have suggested that differentiation of iPSCs can reduce their tendency to activate the immune system after transplantation. However, this study of Wu and others is the first to closely examine, at the molecular and cellular level, how this works.

“We’ve demonstrated definitively that, once the cells are differentiated, the immune response to iPS-derived cells is indistinguishable from its response to unmodified tissue derived from elsewhere in the body,” said lead author Nigel Kooreman.

Pluripotent stem cells have the capacity to differentiate into any cell in the adult body. Of the two types of pluripotent stem cells, embryonic stem cells are made from embryos and iPSCs are made in the laboratory from existing adult cells (e.g., skin or blood). Induced pluripotent stem cells are easier to come by than embryonic stem cells, they match the genetic background of the person from whom they were obtained, and they are not as ethically dubious as embryonic stem cells. Thus, in theory, iPSCs are a good option for any physician who wants to make patient-specific stem cells for potential therapies.

Previous studies in mice have shown, however, that even genetically identicaliPSCs can trigger an immune response after transplantation. Thus, Wu and his colleagues have, for the past six years, been investigating how to use immunosuppressive medications to dampen the body’s response to both embryonic andiPSCs and render them more amenable for clinical use (see AS Lee, et al., J Biol Chem 2011 286(37):32697-704; Durruthy-Durruthy L, et al.,PLoS One, 2014 9(4):e94231 and others).

In this recent study, Kooreman and his co-lead authors decided to examine the immune response against transplanted stem cells. They first transplanted undifferentiated iPS cells into the leg muscles of genetically identical recipient mice. These grafts were rejected and no iPSCs were detected six weeks after transplantation.

Next, Wu and his co-workers differentiated the iPSCs into blood vessel-making endothelial cells that line the interior of the heart and blood vessels and then transplanted them into genetically-identical mice. Kooreman, Almeida, and Meyer then compared the acceptance by the immune system of these iPSC-derived endothelial cells with that of naturally occurring endothelial cells derived from the aortic lining of genetically-identical donor mice. To emphasize once again, all the transplanted cells were genetically identical to the mice in which they were injected. Unlike the undifferentiated iPS cells, both the iPS-derived endothelial cells and the aortic endothelial cells survived for at least nine weeks after transplantation.

Next, Wu and his group repeated the experiment, but they removed the grafts 15 days after transplantation. They observed immune cells called lymphocytes in all grafts, but these immune cells were much more prevalent in the grafts of undifferentiated iPS cells. When the lymphocytes that infiltrated the grafts of undifferentiated iPSCs were compared with those in the differentiated iPSC-derived grafts and the endothelial grafts, their gene expression profiles differed significantly. Those lymphocytes in the undifferentiated iPSC grafts expressed high levels of genes known to be involved in robust immune responses, but lymphocytes in both types of endothelial cell grafts expressed higher levels of genes known to be involved in dampening the immune response and inducing self-tolerance.

Finally, Wu and others directly examined a specific type of lymphocyte called a T cell. Grafts of undifferentiated iPS cells harbored large numbers of T cells that were largely homogeneous, which is characteristic of a robust immune response. Conversely, T cell from grafts of the two types of endothelial cells were more diverse, which suggests a more limited immune response which is typically associated with a phenomenon known as self-tolerance.

“The immune response to the iPS-derived endothelial cells and the aortic endothelial cells, and the longevity of the grafts, was very similar,” said Kooreman. “If we specifically look at the T cells, we see they’re also very similar and that they look much different from grafts that are rejected.”

Wu, who is also a professor of cardiovascular medicine and of radiology, said, “This study certainly makes us optimistic that differentiation — into any nonpluripotent cell type — will render iPS cells less recognizable to the immune system. We have more confidence that we can move toward clinical use of these cells in humans with less concern than we’ve previously had.”

Scientists Make Cloned Stem Cells from Adult Cells


For the first time, stem cell scientists have derived stem cells from cloned human embryos that were made from adult cells.  This brings them closer to developing patient-specific lines of cells that can be used to treat a whole host of human maladies, but at a cost.  This research was described in the April 17th online edition of the journal Cell Stem Cell.

In May of last year, Shoukhrat Mitalipov from the Oregon Health and Science University, reported the derivation of human embryonic stem cells from cloned human embryos.  However, these cloned were made using cells that came from infants.  Miltalipov worked out a new protocol for cloning human embryos by using nonhuman primate embryos, in particular those from a Rhesus monkey.

In this study, the donor cells came from two men, a 35-year-old and a 75-year-old.  By using the protocol developed by Mitalipov and his group, Robert Lanza, Young Gie Chung, and Dong Ryul Lee and their colleagues made personalized embryonic stem cells from these two men.

Stem cell biologist Paul Knoepfler, an associate professor at the University of California at Davis who runs the widely read Stem Cell Blog, called the new research “exciting, important, and technically convincing.”  He continued: “In theory you could use those stem cells to produce almost any kind of cell and give it back to a person as a therapy.”

In their paper, Young Gie Chung from the Research Institute for Stem Cell Research for CHA Health Systems in Los Angeles, Robert Lanza from Advanced Cell Technology in Marlborough, Mass., and their co-authors pointed out the potential promise of this technology for new regenerative therapies.  However, their work is also an important discovery for human cloning, since it shows that age-associated changes are not necessarily an impediment to SCNT-based nuclear reprogramming of human cells.

Even though it was the intent of Chung and others to gestate these cloned embryos to form cloned children, this work could be the first step toward creating a baby with the same genetic makeup as a donor.  Thus, this technology presents a so-called “dual-use dilemma.”

Marcy Darnovsky, executive director of the Berkeley, Calif.-based Center for Genetics and Society, explained that many technologies developed for good can be used in ways that the inventor may not have intended and may not like.

“This and every technical advance in cloning human tissue raises the possibility that somebody will use it to clone a human being, and that is a prospect everyone is against,” Darnovsky said.

This paper represents a collaboration between members of academic laboratories and industry.  Funding for this work came from a private medical foundation and South Korea’s Ministry of Science.

Technically, the somatic-cell nuclear transfer protocols used in paper are still somewhat inefficient.  Chung’s team had to attempt 39 times to produce only two blastocyst-stage embryos.  Their first attempts were complete failures, but when they modified the Mitalipov protocol and activated the cloned embryos 2 hours after fusion rather than 30 minutes after fusion, the embryos grew successfully.

“We have reaffirmed that it is possible to generate patient-specific stem cells using [this] technology,” Chung said.

Shoukhrat Mitalipov, director of the Center for Embryonic Cell and Gene Therapy at Oregon Health & Science University, who developed the method that Chung’s group built upon, said that this work involves eggs that have not been fertilized.

“There will always be opposition to embryonic research, but the potential benefits are huge,” Mitalipov said.

Yes, there will be opposition to destructive research on embryos because they are the youngest among us.  No they do not have the right to vote, drive a car, or buy a hunting license, but they have the right to not be harmed.  To deny them that right because they cannot presently exercise particular capacities assumes that the embryo undergoes essential changes as it develops.  But human embryos develop into the kinds of entities they become because of their intrinsic human nature that drives them to do so.  Yes development is a progressive program that causes the embryo to acquire new structures and capabilities that it previously did not have, but what kind of entity can develop into a human adult that is not itself human?  It takes a human embryo to make a human fetus, which makes a human new-born baby, which makes a human toddler, and do on.  This continuum or development and change occurs throughout or lives and this continuum begins at the end of fertilization.

Cloned embryos begin this continuum at the completion of somatic cell nuclear transfer (SCNT).  SCNT works as a stand-in for fertilization, but the result is still the same – a human embryo.  It also should have the right not to be harmed, but instead she is being produced solely for the purpose of being dismembered.  Is this the way we should treat the smallest and most defenseless among us? surely not.  All this talk about, “well we did not form a fully human being” is a crock.  Yes you did.  You formed a fully formed human embryo.  We were all human embryos at one time and these embryos developed into you and me.  We were inarticulate and incapable at the time, but we gained those capacities over time.  Again, how can something that gives rise to a human child not be human?  The embryo is a human being, but it is a very young human being.  Youth should not disqualify it from being able to live.

Seventeen years ago, when Ian Wilmut from the Roslin Institute in Edinburgh, Scotland announced news about the birth of the first sheep cloned from somatic cells named Dolly, several legislators called for a ban on human cloning.  Several countries took measures to limit or outlaw such work, but in the United States.  The cloning issue was obfuscated by dividing it into “reproductive cloning” for the purposes of making cloned children, and “therapeutic cloning” for the development of new therapies.  Unfortunately, this dichotomy is slightly disingenuous since the techniques for both of these procedures are exactly the same except that reproductive cloning uses a surrogate mother to gestate the cloned embryo and bring her to term.  Both of these procedures produce human embryos, but one uses them to make a baby and the other destroys them before they can do so.

President George W. Bush tried to split the difference by restricting federal funding for stem cell research that harms to a human embryo.  This led to talk of Bush’s “embryonic stem cell ban,” which was inaccurate and was used unfairly used to paint Bush as an idiot.  However, some 15 states have laws addressing human cloning, and about half of them ban both reproductive and therapeutic cloning.

Embryonic stem cell research has typically used embryos that are left over from the fertility industry.  However, some religious groups such as the U.S. Conference of Catholic Bishops and others as well  objected to this, since it destroys a very young human being.

However, about seven years ago, Shinya Yamanaka and his colleagues discovered a way to make induced pluripotent stem cells from mature adult cells.  Genetic engineering techniques could convert ordinary cells into pluripotent stem cells without the need for human eggs.  While this technique did not present the same ethical issues, some induced pluripotent stem cells lines contain significant genetic abnormalities and there is still debate over how safe these cells are for clinical use.

The research conducted by Mitalipov and Chung provides a second way of producing pluripotent cells through laboratory techniques that is, in my view, far less ethical and will almost certainly also have unintended consequences as well.

Encapsulated Stem Cells to Treat Diabetes


A research group from the Sanford-Burnham Medical Research Institute in La Jolla, San Diego, California has used pluripotent stem cells to make insulin-secreting pancreatic beta cells that are encapsulated in a porous capsule from which they secrete insulin in response to rising blood glucose levels.

“Our study critically evaluates some of the potential pitfalls of using stem cells to treat insulin-dependent diabetes,” said Pamela Itkin-Ansari, an adjunct assistant professor with a joint appointment at UC San Diego. “We have shown that encapsulated hESC-derived pancreatic cells are able to produce insulin in response to elevated glucose without an increase in the mass or their escape from the capsule. This means that the encapsulated cells are both fully functional and retrievable.”

For this particular study, Itkin-Ansari and her colleagues used glowing cells to ensure that their encapsulated cells stayed in the capsule. To encapsulate the cells, this group utilized a pouch-like encapsulation device made by TheraCyte, Inc. that features a bilaminar polytetrafluoroethylene (PTFE) membrane system. This pouch surrounds the cells and protects from the immune system of the host while giving cells access to nutrients and oxygen.

With respect to the cells, making insulin-secreting beta cells from embryonic stem cell lines have met with formidable challenges. Not only are beta cells differentiated from embryonic stem cells poorly functional, but upon transplantation, they tend to be fragile and poorly viable.

To circumvent this problem, encapsulation technology was tapped to protect donor cells from the ravages of the host immune system. However, an additional advance made by Itkin-Ansari and her colleagues is that when they encapsulated islet-precursor cells, derived from embryonic stem cells, these cells survived and differentiated into pancreatic beta cells. In fact, islet progenitor cells turn out to be the ideal cell type for encapsulation, since they are heartier, and differentiate into beta cells quite efficiently when encapsulated.

In their animal model tests, these cells remained encapsulated for up to 150 days. Also, as an added bonus, because the progenitor cells develop glucose responsiveness without significant changes in mass, they do not outgrow their capsules.

In order to properly get this protocol to work in humans, Itkin-Ansari and her group has to scale up the size of their capsules and the number of cells packaged into them. Another nagging question is, “How long will an implanted capsule last in a human patient?

“Given the goals and continued successful results, I expect to see the technology become a treatment option for patients with insulin-dependent diabetes,” said Itkin-Ansari.

To date, Itkin-Ansari and others have been able to successfully treat diabetic mice. The problem with these experiments is that they mice were made diabetic by treatment with a drug called beta-alloxan, which destroys the pancreatic beta cells. Human type 1 diabetic patients have an immune system that is sensitized to beta cells. Even though the encapsulation shields the beta cells from contact with the immune system, will this last in human patients with an aggressive immune response against their own beta cells? It seems to me that induced pluripotent cells made from the patient’s own cells would be a better choice in this case than an embryonic stem cell line.

Nevertheless, this is a fine piece of research for diabetic patients.