Misrepresentation of the Embryological Facts of Cloning by Reporters


Wesley Smith at National Review Online has been keeping tabs on the reporting of the Cell paper by Shoukhrat Miltalipov from the Oregon Health and Science University. The misrepresentation has been extensive but it’s not really all that surprising given the ignorance and lack of clear thinking on this issue. Nevertheless, Smith has kept up his yeoman’s work, cataloging the factual errors for reporters in multiple publications.

For his first example, see here, where Loren Grush on Fox News.com wrote:

Through a common laboratory method known as somatic cell nuclear transfer (SCNT), ONPRC scientists, along with researchers at Oregon Health & Science University, essentially swapped the genetic codes of an unfertilized egg and a human skin cell to create their new embryonic stem cells…The combination of the egg’s cytoplasm and the skin cell’s nucleus eventually grows and develops into the embryonic stem cell.

Grush, as Smith points out, is quite wrong. Introducing a nucleus from a body cell into the unfertilized egg and inducing it does not turn the egg into embryonic stem cells, but turns it into a zygote. The zygote them undergoes cleavage (cell division) until it reaches the early/mid blastocyst stage 5-6 days later, then immunosurgery is used to isolated the inner cell mass cells, after which they are cultured. Somatic cell nuclear transfer is a stand-in for fertilization. It produces an embryo and all the redefinition in the world will not change that.

Next comes my favorite newspaper, the Wall Street Journal, which normally has decent to pretty good scientific reporting, but this one story from Gautam Naik contains a real howler:

Scientists have used cloning technology to transform human skin cells into embryonic stem cells, an experiment that may revive the controversy over human cloning. The researchers stopped well short of creating a human clone. But they showed, for the first time, that it is possible to create cloned embryonic stem cells that are genetically identical to the person from whom they are derived.

As Smith points out, Miltalipov and others did not stop short of creating a human clone, then explicitly made a cloned human embryo and therefore made a cloned young human being.

Then there is this humdinger from an online Australian news report:

US researchers have reported a breakthrough in stem cell research, describing how they have turned human skin cells into embryonic stem cells for the first time. The method described on Wednesday by Oregon State University scientists in the journal Cell, would not likely be able to create human clones, said Shoukhrat Mitalipov, senior scientist at the Oregon National Primate Research Center. But it is an important step in research because it doesn’t require the use of embryos in creating the type of stem cell capable of transforming into any other type of cell in the body.

Oh my gosh, folks the paper describes the production of cloned embryos expressly for the purpose of dismembering them and destroying them. This “doesn’t require the use of embryos” crap reveals a very basic ignorance of how the experiment was done. See Smith’s excellent post for more details.

Then there is this story from one of my least favorite papers, the LA Times:

Some critics continue to argue that it’s unethical to manipulate the genetic makeup of human eggs even if they’re unfertilized, and others warn about potential harm to egg donors. The biggest ethical issue for the OHSU team, though, is that it artificially created a human embryo, albeit one that was missing the components needed for implantation and development as a fetus.

Come on people! The cloned embryo does not have the components needed to implant because there is no womb into which it can be implanted. Dolly was made the same way. Surely Dolly had the components required to implant.  The problem here is one of will, since these embryos were made to be destroyed. Not capacity. What was done to those embryos was dismemberment. Would we object if they were toddlers?

Just to show that obfuscation is not wholly an American news feature, there is this story from the German newspaper Deutche Welle:

Scientists, for the first time, have cloned embryonic stem cells using reprogrammed adult skin cells, without using human embryos…The process used by Mitalipov is an important step in research because it does not require killing a human embryo–that is, a potential human being–to create transformative stem cells.

As Smith points out, this research made a human embryo that was then killed to make embryonic stem cells. Calling this research humane is to redefine humane to the point of absurdity.

Finally this jewel of blithering ignorance from bioethicist Jonathan Moreno in his column in the Huffington Post:

Despite some confused media reports, the Oregon scientists did not clone a human embryo but a blastocyst that lacks some of the cells needed to implant in a uterus.

And you wonder why people like me have lost all faith in American bioethics. As a developmental biologist, this one just grates on me.  A blastocyst has two cell populations; an outer trophectoderm composed of trophoblast cells that will form the placenta and the inner cell mass cells on the inside of the embryo, which will form the embryo proper and a few placental structures. To be a blastocyst is to have the equipment to implant.

To drive the nail into the coffin, Smith quotes the father of embryonic stem cells James Thomson from an MSNBC interview:

See, you are trying to redefine it away…If you create an embryo by nuclear transfer, if you gave it to somebody who didn’t know where it came from, there would be no test you could do on that embryo to say where it came from. It is what it is. By any reasonable definition, at least as some frequency, you are creating an embryo. If you try to redefine it away, you are being disingenuous.

Check out Smith’s posts. They are all worth reading. Maybe the press will learn some embryology, but I doubt it.

Postscript:  Brendan P. Foht writes at the Corner on National Review Online that in 2010 Shoukhrat Mitalipov, the leader of the Oregon cloning team, reported that he had achieved a single pregnancy using cloned monkey embryos that were made with exactly the same technology as was employed with human eggs in his 2013 Cell paper.  The fetus developed long enough to have a heartbeat detectable through ultrasound. Although the pregnancy failed after 81 days (about half the normal gestation period for that species), the fact that a pregnancy would develop so far indicates that reproductive cloning of primates is in principle possible.  This definitively shows that all this talk about the embryos made in Mitalipov’s lab not being able to implant is pure drek.

Mesenchymal Stem Cells Engineered to Express Tissue Kallikrein Increase Recovery After a Heart Attack


Julie Chao is from the Department of Biochemistry and Molecular Biology, at the Medical University of South Carolina. Dr. Chao and her colleagues have published a paper in Circulation Journal about genetically modified mesenchymal stem cells and their ability to help heal a heart that has just experienced a heart attack.

Several laboratories have used mesenchymal stem cells (MSCs), particularly from bone marrow, to treat the hearts of laboratory animals that have recently experienced a heart attack. However, heart muscle after a heart attack is a very hostile place, and implanted MSCs tend to pack up and die soon after injection. Therefore, such injected cells do little good.

To fix this problem, researchers have tried preconditioning cells by growing them in a harsh environment or by genetically engineering them with genes that can increase their tolerance of harsh environments. Both procedures have worked rather well. In this paper, Chao and her group engineered bone marrow-derived MSCs to express the genes that encode “tissue kallikrein” (TK). TK circulates throughout our bloodstream but several different types of cells also secrete it. It is an enzyme that degrades the protein “kininogen” into small bits that have several benefits. Earlier studies from Chao’s own laboratory showed that genetically engineering TK into the heart improved heart function after a heart attack and increased the ability of MSCs to withstand harsh conditions (see Agata J, Chao L, Chao J. Hypertension 2002; 40: 653 – 659; Yin H, Chao L, Chao J. Journal of  Biol Chem 2005; 280: 8022 – 8030). Therefore, Chao reasoned that using MSCs engineered to express TK might also increase the ability of MSCs to survive in the post-heart attack heart and heal the damaged heart.

In this paper, Chao and others made adenoviruses that expressed the TK gene. Adenoviruses place genes inside cells, but they do not integrate those genes into the genome of the host cell. Therefore, they are safer to use than retroviruses. Chao and others used these TK-expressing adenoviruses to infect tissue and MSCs.

When TK-expressing MSCs were exposed to low-oxygen conditions, like what cells might experience in a post-heart attack heart, the TK-expressing cells were much heartier than their non-TK-expressing counterparts. When injected into rat hearts 20 minutes after a heart attack had been induced, the TK-expressing MSCs showed good survival and robust TK expression. Control hearts that had been injected with non-TK-expression MSCs or had not been given a heart attack showed no such elevation of TK expression.

There were also added bonuses to TK-expressing MSC injections. The amount of inflammation in the hearts was significantly less in the hearts injected with TK-expressing MSC injections compared to the controls. There were fewer immune cells in the heart 1 day after the heart attack and the genes normally expressed in a heart that is experiencing massive inflammation were expressed at lower levels relative to controls, if they were expressed at all.

Reduced inflammation by TK-MSC administration was determined by (C) ED-1 immunohistochemical staining, (D) monocyte/macrophage quantification, (E) neutrophil quantification, and gene expression of (F) TNF-α, (G) ICAM-1, and (H) MCP-1. ED-1-positive cells are indicated by arrows. Original magnification, ×200. Data are mean ± SEM (n=5–8). *P<0.05 vs. other MI groups; **P<0.05 vs. MI/Control group. MSC, mesenchymal stem cell.
Reduced inflammation by TK-MSC administration was determined by (C) ED-1 immunohistochemical staining, (D) monocyte/macrophage quantification, (E)
neutrophil quantification, and gene expression of (F) TNF-α, (G) ICAM-1, and (H) MCP-1. ED-1-positive cells are indicated by arrows.
Original magnification, ×200. Data are mean ± SEM (n=5–8). *P

Another major bonus to the injection of TK-expressing MSCs into the hearts of rats was that these cells protected the heart muscle cells from programmed cell death. To make sure that this was not some kind of weird artifact, Chao and her team placed the TK-expressing MSCs in culture with heart muscle cells and then exposed them to low-oxygen tension conditions. Sure enough, the heart muscle cells co-cultured with the TK-expressing MSCs survived better than those co-cultured with non-TK-expressing MSCs.

TK-MSCs protect against cardiac cell apoptosis at 1 day after myocardial infarction (MI) and in vitro. TK-MSC administration reduced apoptosis in the infarct area at 1 day after MI, as determined by (A) TUNEL staining, (B) quantification of apoptotic cells, and (C) caspase-3 activity. Original magnification, ×200. Data are mean ± SEM (n=5–8). *P<0.05 vs. other MI groups. Cultured cardiomyocytes treated with 0.5 ml of TK-MSC-conditioned medium exhibit higher tolerance to hypoxia-induced apoptosis, as evidenced by (D) Hoechst staining,
TK-MSCs protect against cardiac cell apoptosis at 1 day after myocardial infarction (MI) and in vitro. TK-MSC administration
reduced apoptosis in the infarct area at 1 day after MI, as determined by (A) TUNEL staining, (B) quantification of apoptotic
cells, and (C) caspase-3 activity. Original magnification, ×200. Data are mean ± SEM (n=5–8). *Pcardiomyocytes treated with 0.5 ml of TK-MSC-conditioned medium exhibit higher tolerance to hypoxia-induced apoptosis, as
evidenced by (D) Hoechst staining,

Finally, when the hearts of the rats were examined 2 weeks after the heart attack, it was clear that the enlargement of the heart muscle (so-called “remodeling”) occurred in animals that had received non-TK-expressing MSCs or had received no MSCs at all, but did not occur in the hearts of rats that had received injections of TK-expressing MSCs. The heart scar was also significantly smaller in the hearts of rats that had received injections of TK-expressing MSCs, and had a greater concentration of new blood vessels. Apparently, the TK-expressing MSCs induced the growth of new blood vessels by recruiting EPCs to the heart to form new blood vessels.

In conclusion, the authors write that “MSCs genetically-modified with human TK are a potential therapeutic for ischemic heart diseases.”

Getting FDA approval for genetically engineered stem cells will not be easy, but TK engineering seems much safer than some of the other modifications that have been used. Also the vascular and cardiac benefits of this gene seem clear in this rodent model. Pre-clinical trials with larger animals whose cardiac physiology is more similar to humans is definitely warranted and should be done before any talk of human clinical trials ensues.

Adult Mammals Lack the Stem Cell Activity to Make New Eggs


Recent research in mice and humans have discovered a stem cell population in ovaries that can form eggs. However, this discovery begs a question: namely, why do adult female mammals run out of eggs in their lifetime if they have a stem cell population that can produce eggs?

New research from the Carnegie Institute for Science demonstrates that adult mice do not use stem to produce new eggs, thus answering this apparent conundrum.

Before birth, mouse and human ovaries contain an abundant supply of germ cells that originate from primordial germ cells that form from the inner layer of the primary umbilical vesicle (otherwise known as the yolk sac).  Between the time when the embryo is four to six weeks old, the primordial germ cells (PGCs) migrate from the wall of the primary umbilical vesicle to the gut tube.  From the gut tube, the PGCs migrate to the dorsal body wall by means of the mesentery that suspends the gut from the body wall.  Once in the body wall, the PGCs come to rest on either side of the midline in the loose mesenchymal tissue just inside the membranous lining of the body cavity (known more technically as the coelomic cavity).

PGC Migration Pathway2

Most of the PGCs populate the region of the body wall at the level that will form the gonads.  During their migration, PGCs continue to multiply by means of mitosis, which increase their numbers substantially.  Some PGCs may become stranded during their migration, coming to rest at extragonadal sites.  Occasionally, stray germ cells of this type may give rise to a type of tumor called a teratoma.

Teratoma
Teratoma

Once in their final location, the PGCs will stimulate the formation of the genital or gonadal ridge.

In females, PGCs (which are now called gonocytes) undergo a few more mitotic divisions after they are surrounded by the somatic support cells and become intimately associated with them.  The gonocytes differentiate into oogonia, and by the 5th month of fetal development all oogonia initiate meiosis.  After they initiate meiosis, the oogonia are called primary oocytes.  However, during an early phase of meiosis all sex cells enter a state of dormancy, and they remain in meiotic arrest as primary oocytes until sexual maturity.  Beginning at puberty, each month a few ovarian follicles resume development in response to the monthly surge of pituitary gonadotropic  hormones, but usually only one primary oocyte matures into a secondary oocyte and is ovulated. This oocyte enters a second phase of meiotic arrest and does not actually complete meiosis unless it is fertilized. These monthly cycles continue until the onset of menopause at approximately 50 years of age.

Near the time of birth, the ovaries of mice and humans contain an abundant supply of eggs that will be released from follicles during ovulation each menstrual cycle.  At the birth of the baby, she will possess a large reserve of primordial follicles that contain a single egg surrounded by supporting follicle cells.  Evidence of new follicle production is absent after birth.  Therefore, it has long been thought that the supply of follicles is fixed at birth and eventually is exhausted at menopause.

During the last decade, researchers have found primordial follicles in adult mouse ovaries that turn over and claimed that adult germ-line stem cells constantly resupply the follicle pool and sustain ovulation.  These claims were based on observations of ovarian tissue and one the behavior of extremely rare ovarian cells after these cells were cultured for some time in the laboratory.  Such criteria are subjective, especially in light of the fact that culturing cells for long periods of time in the laboratory can effectively reprogram them.

At Carnegie, Lei Lei and Allan Spradling used a technique that tracks individual cells and their progeny within living tissue over a specific time course.  The cells are marked with a gene, and this gene is inherited by the progeny of that cell, thus allowing the careful tracking of all the progeny of that cell or those cells.  This technique is called “lineage tracking” and it is a very popular technique in developmental and cell biology.

By subjecting primordial follicles to lineage tracking, Lei and Spradling showed that germ-line stem cell activity cannot be detected in mice.  Furthermore, primordial follicles are stable, and even if half the existing follicles die off, no germ-line stem cell activity is detectable.  This research does not prove that there are no germ-line stem cell divisions within the ovary of the mouse, but it does place an upper limit on the divisions of the germ-line stem cell population of one division every two weeks at the most, which is biologically insignificant.

What then can be said about the germ-line stem cell cultures isolated in the laboratory?  According to Alan Spradling, the cells “likely arise by dedifferentiation in culture,” and “the same safety and reliability concerns would apply as to any laboratory-generated cell type that lacks a normal counterpart” in the body.

This should be a warning to those conclusions that are solely derived from experiments conducted in culture alone and not in a living creature as well.

Neurons Made from the Skin Cells of Down Syndrome Patients Show Reduced Connectivity


The most common form of intellectual disability in the United States is caused by Down syndrome (DS). DS results when babies are born with an extra copy of an extra piece of chromosome 21. Individuals with DS show various types of intellectual deficits and other health problems as well, such as heart problems, poor muscle tone, an under-active thyroid, respiratory infections, hearing problems, celiac disease, eye conditions, depression or behavior problems associated with attention-deficit hyperactivity disorder or autism.

Even though Down syndrome patients have symptoms and health problems that are well described, how the extra chromosome causes such widespread effects is still largely mysterious.

In recently published research, Anita Bhattacharyya, who is a neuroscientist at the Waisman Center at the University of Wisconsin-Madison, reported that brain cells that were grown from skin cells taken from individuals with Down syndrome.

“Even though Down syndrome is very common, it’s surprising how little we know about what goes wrong in the brain,” says Bhattacharyya. “These new cells provide a way to look at early brain development.”

The skin cells taken from DS patients were grown in culture and genetically engineered to so that a fraction of them were transformed into induced pluripotent stem cells (iPSCs). Since iPSCs can be differentiated into any adult cell type, Bhattacharyya’s lab, working with collaboration with Su-Chun Zhang and Jason Weick, grew those iPSCs in culture and differentiated them into dorsal forebrain neurons, which they could test in the laboratory.

Neurophysiological tests of the DS neurons revealed that these neurons formed a reduced number of connections between them each other. Bhattacharyya says. “They communicate less, are quieter. This is new, but it fits with what little we know about the Down syndrome brain.” Brain cells communicate through connections called synapses, and the Down neurons had only about 60 percent of the usual number of synapses and synaptic activity. “This is enough to make a difference,” says Bhattacharyya. “Even if they recovered these synapses later on, you have missed this critical window of time during early development.”

Bhattacharyya and colleagues also examined the genes that were affected in the Down syndrome stem cells and neurons. They discovered that those genes on the extra chromosome were increased 150 percent, which is consistent with the contribution of the extra chromosome.

However, the output of about 1,500 genes elsewhere in the genome was strongly affected. “It’s not surprising to see changes, but the genes that changed were surprising,” says Bhattacharyya. The predominant increase was seen in genes that respond to oxidative stress, which occurs when molecules with unpaired electrons called free radicals damage a wide variety of tissues.

“We definitely found a high level of oxidative stress in the Down syndrome neurons,” says Bhattacharyya. “This has been suggested before from other studies, but we were pleased to find more evidence for that. We now have a system we can manipulate to study the effects of oxidative stress and possibly prevent them.”

DS includes a range of symptoms that might result from oxidative stress, Bhattacharyya says, including accelerated aging. “In their 40s, Down syndrome individuals age very quickly. They suddenly get gray hair; their skin wrinkles, there is rapid aging in many organs, and a quick appearance of Alzheimer’s disease. Many of these processes may be due to increased oxidative stress, but it remains to be directly tested.”

Oxidative stress could be especially significant, because it appears right from the start in the stem cells. “This suggests that these cells go through their whole life with oxidative stress,” Bhattacharyya adds, “and that might contribute to the death of neurons later on, or increase susceptibility to Alzheimer’s.”

Other researchers have created neurons with DS from induced pluripotent stem cells, Bhattacharyya notes. “However, we are the first to report this synaptic deficit, and to report the effects on genes on other chromosomes in neurons. We are also the first to use stem cells from the same person that either had or lacked the extra chromosome. This allowed us to look at the difference just caused by extra chromosome, not due to the genetic difference among people.”

The research, published the week of May 27 in the Proceedings of the National Academy of Sciences, was a basic exploration of the roots of Down syndrome. Bhattacharyya says that while she did not intend to explore treatments in this work, she did note that “we could potentially use these cells to test or intelligently design drugs to target symptoms of Down syndrome.”

Circulating Factor Rejuvenates the Hearts of Older Mice


Two researchers associated with the Harvard Stem Cell Institute, one of whom is a practicing cardiologist at Brigham and Women’s Hospital, and a cell biologist have identified a protein in the blood of mice and humans decreases during aging and may prove to be the first effective treatment for the form of age-related heart failure that affects millions of Americans.

Growth Differentiation Factor 11 or GDF11 circulates throughout the bloodstream of humans and mice. Injections of GDF11 into old mice that have developed thickened heart walls in a manner similar to aging humans, the hearts were reduced in size and thickness, and resembled the healthy hearts of younger mice.

Even more important than the implications for the treatment of diastolic heart failure, the finding by Richard T. Lee, from Harvard Medical School and Amy Wagers, who is a professor in Harvard’s Department of Stem Cell and Regenerative Medicine, might rewrite our understanding of aging. These findings were published in the prestigious, international journal Cell.

“The most common form of heart failure [in the elderly] is actually a form that’s not caused by heart attacks but is very much related to the heart aging,” said Lee, who, like Wagers, is a principal faculty member at HSCI.

“In this study, we were able to show that a protein that circulates in the blood is related to this aging process, and if we gave older mice this protein, we could reverse the heart aging in a very short period of time,” Lee said. “We are very excited about it because it opens a new window on the most common form of heart failure.”
He added, “This is the coolest thing I’ve ever been a part of.”

Doug Melton, HSCI co-director, called the discovery “huge. It’s going to change the way we think about aging.”

Lee, who practices medicine as a cardiologist, noted that he has approximately 300 patients, and of these “I think I have about 20 who are suffering from this type of heart failure, which we sometimes call diastolic heart failure,” said Lee. “They come into the hospital, have a lot of fluid taken off, then they’ll go home. Then they come back again. It’s really frustrating because we don’t have any drugs to treat this. We need to work as hard as we can to figure out if this discovery can be turned into a treatment for heart failure in our aging patients.”

The Lee and Wagers labs would like to move GDF-11 toward clinical trials. Lee predicts that they might be able to begin these studies in four to five years. However, they need to determine the other tissues that are affected by GDF11.

Wagers was a postdoctoral research fellow at Stanford University, where she learned how to work with the “parabiotic” mouse system. Parabiosis refers to two animals that share a common circulatory system. Wagers used this system to link the circulatory system of young mice with that of older mice. When she did that, she and her colleagues discovered that soluble factors in the blood of young animals have a rejuvenating effect on various tissues in older animals. In particular, the spinal cord and the musculature of the older animals showed marked improvements.

“As we age, there are many changes that occur in different parts of the body,” Wagers said, “and those changes are often associated with a decline in the function of our bodies. One of the interests of my laboratory is in understanding why this happens and whether it is an inevitable consequence of aging, or if it might be reversible.

“In this study, we compared young and old animals and identified a substance in the blood that is present at high levels when you’re young and lower levels when you’re old. We further found that when we supplemented the low levels of this substance that were present in old animals to the levels normally seen in youth, this could have a dramatic effect on the heart.

“It’s been observed for many, many years that when aging occurs it affects multiple body systems sort of in a semi-synchronous way,” Wagers said, “and this suggests that there may be some common signal that drives the body’s response to getting older. We hypothesized that this common signal might be a substance that was traveling in the bloodstream, because the bloodstream accesses organs throughout the body.”

“I think Amy and I started thinking about something like this almost five years ago,” said Lee, who added that he and Wagers were brought together by HSCI. “Without the Harvard Stem Cell Institute, this never would have happened,” he said.

Lee and Wagers conducted their first experiment about four years ago, and the results were startling, Lee said. “A fellow named Francesco Loffredo was examining the hearts of the aging mice. He came to me and said, ‘You don’t have to analyze it; you can see it with the naked eye.’ I couldn’t believe that, and I said ‘Go back, analyze it, and do it blinded.’ Then I looked at the hearts, and I could see he was correct,” Lee recalled.

“When we started these experiments, I actually was thinking that there would not be a response,” Wagers said. “We had been using similar kinds of approaches in other tissues, regenerative tissues, tissues that we know have the capacity to heal themselves after they’ve been injured. But the heart is not well known for doing that, and so I was quite convinced that there would be no response. When I saw the dramatic difference in heart size that was very apparent after this exposure of an old animal to young blood, it was very clear that we had to figure out what was going on,” she said.

“The blood is full of all kinds of things,” the biologist said, “and trying to narrow down what might be the responsible factor was going to be a big challenge. I think that’s where the collaboration was so wonderful; in that we could take advantage of the expertise in both of our laboratories to really home in on what might be the responsible substance.”

Lee explained, “We thought it was interesting right away, and we repeated it right away. But we had to show that this was not a blood pressure effect, that the young mice didn’t just cause the old mice to have lower blood pressure. We had to build a custom device to measure blood pressures off their tails. It took a year to do the analysis to show that it was not a blood pressure effect.

“After about 2½ years we were convinced, and said, ‘we really have to identify this factor.’ It took about six months to find something, and another year to be convinced that it was real,” Lee said. “We looked at lipids; we looked at metabolites. Then we set up a collaboration with a startup company in Colorado, called SomaLogic that had an interesting technology for analyzing factors in blood. And by working closely with SomaLogic, we found the likely factor.”

They discovered that at least one of the factors responsible for heart rejuvenation was GDF-11, “a member of a very important family of proteins called TGF-beta proteins, for transforming growth factor. There are around 35 members of the family,” Lee said. “Some have been very well studied, and this is one that is relatively obscure.”

The work was supported in part by HSCI, the National Institutes of Health, and the American Heart Association.

Human Brain Cells Made in the Lab that Grow in the Mouse Brain


The laboratory of Arnold Kriegstein, who serves as the director of the Broad Center of Regenerative Medicine and Stem Cell Research at UC San Francisco has made a vitally important type of brain cell from human pluripotent stem cells that smoothly integrates into the brains of laboratory animals. Such a discovery could potentially provide cells that could treat epileptics, Parkinson’s disease or even Alzheimer’s disease.

Medial ganglionic eminence (MGE) cells are a unique type of progenitor cell in the developing brain that guides cell and axon migration. The MGE is located between the thalamus and the caudate nucleus in the developing brain and it facilitates tangential cell migration during embryonic development in the brain.

In the developing brain, cells move radially, along special glial cells that act as tracts for the migrating cells, or tangentially between the radial glial cells. Those cells that move tangentially (perpendicular to the radial glial cells) are specially designated to form GABAminergic neurons; that is neurons that use gamma-amino-butyric acid as their neurotransmitter. However, the MGE also contributes cells to the basal ganglia, which helps control voluntary movement, and guides those axons that grow from the thalamus into the cerebral cortex, or, conversely, those axons that grow from the cerebral cortex to the thalamus. The MGE is a transient structure, and after one year of age, the MGE disappears.

medial ganglionic eminence

Making MGE cells from pluripotent stem cells has been one of the holy grails of developmental neurobiology. Now Kirgstein’s laboratory has succeeded in doing just that.   By subjecting human embryonic stem cells and induced pluripotent stem cells to a complex and extensive differentiation procedure, Kirgstein and his coworkers succeeded in producing large quantities of MGE progenitors that readily matured into forebrain interneurons.  They treated pluripotent stem cells with several growth factors, but more importantly, they timed the delivery of these factors to shape their developmental path.  By conducting neurophysiological experiments on the cells as they differentiated them, Kirgstein and coworkers discovered that they could effectively determine if they had properly derived GABAminergic interneurons.  Jiadong Chen in Kirgsteins’s laboratory showed that the MGE-like progenitors formed proper synapses or connections with other neurons and responded appropriately when stimulated.  Also, as the interneurons matured into more adult-like interneurons, their neurophysiology became more adult-like.  

When grown in the laboratory in culture or when injected into the brains of mice, these MGE-like cells developed into GABAergic interneuron subtypes that displayed the properties of mature GABAminergic neurons.  Also, the cells kept these properties for up to 7 months, and therefore, faithfully mimicked endogenous human neural development.

When injected into mouse brains, the MGE-like progenitors integrated into the brain and formed connections with existing cells.  According to Kirgstein, this property of these cells and their behavior in living tissue makes them prime candidates to test interneuron malfunction that is characteristic of human diseases.  They might also provide material to treat patients who suffer from neurological diseases that affect interneuron function.

According to Kirgstein, “We think that this one type of cell may be useful in treating several types of neurodevelopmental and neurodegenerative disorders in a targeted way.”

In earlier work, Kirgstein implanted mouse MGE cells into the spinal cord of mice that suffered from neuropathic pain.  The implanted cells reduced the pain of those mice, suggesting that they can be used to treat other neurological conditions such a spasticity, Parkinson’s disease and epilepsy.

The first author of this paper, Cory Nicholas said, “The hope is that we can deliver these cells to various places within the nervous system that have been overactive and that they will functionally integrate and provide regulated inhibition.”

Baby from Ohio Saved With An Airway Splint Made by A 3-D Printer


A baby boy from Ohio, Kaiba (KEYE’-buh) Gionfriddo, was born with a trachea (windpipe) that was fragile and kept collapsing. Without precious oxygen, he choked and passed out. Even though the physicians attending him thought about using an airway splint to open his airway, they had yet to implant it. Kaiba was not getting any better, and without a way to get him the oxygen that his little body desperately needed, he did not have much time. All he could do was lie in a hospital bed on a breathing machine.

Kaiba Gionfriddo

To solve this problem, the doctors used plastic particles and a 3-D laser printer to generate an airway splint to deliver oxygen to his lungs. This is a technological first and is the latest advance in the quickly advancing field of regenerative medicine that tries to make human body parts in the lab.

The even more stupendous aspect of this feat is that the production of the tracheal tube only too k one day. Yes, in a single day they “printed out” 100 tiny tubes by employing computer-guided lasers to stack and fuse thin layers of plastic to form various shapes and sizes. The next day, with special permission from the US Food and Drug Administration, they implanted one of these tubes in Kaiba. Needless to say, this is the first time such a treatment has even been done.

Suddenly, Kaiba, whom doctors said would probably never leave the hospital alive, could breathe normally for the first time. Kaiba was 3 months old when the operation was done last year and is nearly 19 months old now. He is about to have his tracheotomy tube removed since it was placed in his throat when he was a couple of months old. He no longer needs a breathing machine and has had not had a single breathing crisis since coming home a year ago.

“He’s a pretty healthy kid right now,” says Dr. Glenn Green, a pediatric ear, nose and throat specialist at C.S. Mott Children’s Hospital of the University of Michigan in Ann Arbor, where the operation was done. This remarkable feat of tissue engineering is described in the New England Journal of Medicine.

Independent experts have highly praised this and the potential 3-D printing provides for creating and quickly manufacturing body parts to solve unmet medical needs.

“It’s the wave of the future,” says Dr. Robert Weatherly, a pediatric specialist at the University of Missouri in Kansas City. “I’m impressed by what they were able to accomplish.”

So far, only a few adults have had trachea, or windpipe transplants, and these are usually used to replace windpipes destroyed by cancer. The windpipes came from dead donors or were lab-made, sometimes using stem cells. Last month, a 2-year-old girl born without a windpipe received one grown from her own stem cells on a plastic scaffold at a hospital in Peoria, Ill.

Kaiba, however, had a different problem; namely an incompletely formed bronchus. The bronchi are the tubes that branch from the windpipe to the lungs. Approximately 2,000 babies are born with such defects each year in the United States and most outgrow them by age 2 or 3, as they grow and mature and their respiratory tract replaces the lost tissues.

In severe cases, parents learn of the defect when the child suddenly stops breathing and dies. That almost happened when Kaiba was 6 weeks old at a restaurant with his parents, April and Bryan Gionfriddo, who live in Youngstown, in northeast Ohio. “He turned blue and stopped breathing on us,” and his father did CPR to revive him, April Gionfriddo says.

More episodes followed, and Kaiba had to go on a breathing machine when he was 2 months old. Doctors told the couple his condition was grave. “Quite a few of them says he had a good chance of not leaving the hospital alive. It was pretty scary,” his mother says. “We pretty much prayed every night, hoping that he would pull through.”

Fortunately a physician at Akron Children’s Hospital named Dr. Marc Nelson suggested the experimental work in Michigan in which researchers were testing airway splints made from biodegradable polyester that are sometimes used to repair bone and cartilage.

Kaiba had the operation on Feb. 9, 2012. The splint was placed around his defective bronchus, which was stitched to the splint to keep it from collapsing. The splint has a slit along its length so it can expand and grow as the child does — something a permanent, artificial implant could not do.

The plastic from which the splint is made is designed to degrade and gradually be absorbed by the body over three years, as healthy tissue forms to replace it, according to the biomedical engineer who led the work, Scott Hollister.

Green and Scott Hollister have a patent pending on the device and Hollister has a financial interest in a company that makes scaffolds for implants.

Dr. John Bent, a pediatric specialist at New York’s Albert Einstein College of Medicine, says only time will tell if this proves to be a permanent solution, but he praised the researchers for persevering to develop it.

“I can think of a handful of children I have seen in the last two decades who suffered greatly … that likely would have benefited from this technology,” Bent says.