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.

Human STAP cells – Troubling Possibilities


Soon after the publication of this paper that adult mouse cells could be reprogrammed into embryonic-like stem cells simply by exposing them to acidic environments or other stresses , Charles Vacanti at Harvard Medical School has reported that he and his colleagues have demonstrated that this procedure works with human cells.

STAP cells or stimulus-triggered acquisition of pluripotency cells were derived by Vacanti and his Japanese collaborators last year. These new findings show that adult cells can be reprogrammed into embryonic-like stem cells without genetic engineering. However, this technique worked well in mouse cells, but it was not clear that it would work with human adult cells.

Vacanti and others shocked the world when they published their paper in the journal Nature earlier this year when they announced that adult cells in mice could be reprogrammed through exposure to stresses and proper culture conditions.

Now Vacanti has made good on his promise to test his protocol on human adult cells. In the photo below, provided by Vacanti, human adult cells were reprogrammed to a pluripotent state by exposing them to stresses, followed by growth in culture under specific conditions.

Human STAP cells
Human STAP cells

“If they can do this in human cells, it changes everything, said Robert Lanza of Advanced Cell Technologies in Marlborough, Massachusetts. Such a procedure promises cheaper, faster, and potentially more flexible cells for regenerative medicine, cancer therapy and cell and tissue cloning.

Vacanti and his colleagues say they have taken human fibroblast cells and tested several environmental stressors on them to recreate human STAP cells. He will not presently disclose which particular stressors were applied, he says the resulting cells appear similar in form to the mouse STAP cells. His team is in the process of testing to see just how stem-cell-like these cells are.

According to Vacanti, the human cells took about a week to resemble STAP cells, and formed spherical clusters just like their mouse counterparts. Vacanti and his Harvard colleague Koji Kojima emphasized that these results are only preliminary and further analysis and validation is required.

Bioethical problems potentially emerge with STAP cells despite their obvious potential. The mouse cells that were derived and characterized by Vacanti’s group and his collaborators were capable of making placenta as well as adult cell types. This is different from embryonic stem cells, which can potentially form all adult cell types, but typically do not form placenta. Embryonic stem cells, therefore, are pluripotent, which means that they can form all adult cell types. However, the mouse STAP cells can form all embryonic and adult cell types and are, therefore, totipotent. Mouse STAP cells could form an entirely new mouse. While it is now clear if human STAP cells, if they in fact exist, have this capability, but if they do, they could potentially lead to human cloning.

Sally Cowley, who heads the James Martin Stem Cell Facility at the University of Oxford, said of Vacanti’s present experiments: “Even if these are STAP cells they may not necessarily have the same potential as mouse ones – they may not have the totipotency – which is one of the most interesting features of the mouse cells.”

However the only cells known to be naturally totipotent are in embryos that have only undergone the first couple of cell divisions immediately after fertilization. According to Cowley, any research that utilizes totipotent cells would have to be under very strict regulatory surveillance. “It would actually be ideal if the human cells could be pluripotent and not totipotent – it would make everyone’s life a lot easier,” she opined.

Cowley continued: “However, the whole idea that adult cells are so plastic is incredibly fascinating,” she says. “Using stem cells has been technically incredibly challenging up to now and if this is feasible in human cells it would make working with them cheaper, faster and technically a lot more feasible.”

This is all true, but Robert Lanza from Advanced Cell Technology in Marlborough, Massachusetts, a scientist with whom I have often deeply disagreed, noted: “The word totipotent brings up all kinds of issues,” says Robert Lanza of Advanced Cell Technology in Marlborough, Massachusetts. “If these cells are truly totipotent, and they are reproducible in humans then they can implant in a uterus and have the potential to be turned into a human being. At that point you’re entering into a right-to-life quagmire”

A quagmire indeed, for Vacanti has already talked about using these STAP cells to clone human embryos. Think of it: the creation of very young human beings just for the purpose of ripping them apart and using their cells for research or medicine. Would we allow this if the embryo were older; say the age of a toddler? No we would rightly condemn it as murder, but because the embryo is very young, that somehow counts against it. This is little more than morally grading the embryo according to astrology.

Therefore, whole Vacanti’s experiments are exciting and novel, they hold chilling possibilities. Lanza is right, and it is doubtful that scientists would show the same deference or sensitivities to the moral exigencies he has shown.

Japanese first Ever Induced Pluripotent Stem Cell Clinical Trial Given the Green Light


The first clinical trial that utilizes induced pluripotent stem cells has been given a green light. For this clinical trial six patients who suffer from age-related macular degeneration will donate skin biopsies and the cells from these skin biopsies will be used to generate induced pluripotent stem (iPS) cells in the laboratory. After those iPS cell lines are screened for safety (normal numbers of chromosomes, no mutations in critical genes, etc.), they will be differentiated into retinal cells. The retinal cells will be transplanted into the retinas of these six patients.

This clinical trial was approved by Japan Health Minister Norihisa Tamura and it will be next summer by Masayo Takahashi. Dr. Takahashi is a retinal regeneration expert and a colleague of the man who first developed iPS cells, Shinya Yamanaka. Yamanaka won the Nobel Prize for his discovery of iPSCs last year. In fact, this clinical trial epitomizes, in the eyes of many, the determination of Japanese scientists and politicians to dominate the iPS cell field. This national ambition kicked into high gear after Yamanaka shared the Nobel Prize for Physiology or Medicine last October for his iPS cell work.

Norhisa Tamura, Japanese Minister of Health
Norihisa Tamura, Japanese Minister of Health
Masayo Takahashi, MD, PhD, Riken Center for Developmental Biology.
Masayo Takahashi, MD, PhD, Riken Center for Developmental Biology.

“If things continue this way, this will be the first in-clinic study in iPS cell technology,” says Doug Sipp of the Riken Center for Developmental Biology (CDB). The CDB, Takahashi’s institute, will co-run the trial with Kobe’s Institute for Biomedical Research and Innovation. “It’s exciting.”

Sipp, however, also noted that this move has not surprised anyone in Japan, since the Japanese stem cell community has heavily invested in iPS cells. Nevertheless, since Takahashi yet to formally publish the details of her trial, some have questioned whether she is actually ready to move forward. IPS cells are viewed as the perfect compromise for regenerative medicine. They are adult, and therefore do not require the destruction of human embryos for their establishment, and they are also pluripotent like an embryonic cell, which makes them relatively powerful sources for regenerative medicine.

Critics, however, warn that iPS cells were only discovered in 2007. To date, they remain difficult to create and culture and they can become tumorous in many hands. However, many labs have a great deal of expertise and skill when it comes to handling and deriving iPS cells. These labs derive and culture iPS cells routinely. In fact, Sipp notes that Riken’s CDB alone has produced world-class work with all kinds of stem cells, including embryonic stem (ES) cells, which are the models for iPS cells.

Additionally, Sipp and others point out that a scientist who has collaborated with Takahashi in the past, Riken’s Yoshiki Sasai, is doing groundbreaking work with ES cells and the eye. The British journal Nature has called Sasai “The Brainmaker,” and has said that his research is “wowing” the world.

The Japanese government has also soundly funded Takahashi’s trail. The health ministry’s recent stimulus plan set aside more money for stem cells (in particular iPS cells) than anything else. According to the journal Nature, the Japanese government sequestered 21.4 billion yen ($215 million) for stem cell research. Of this pot of money, the health ministry provided 700 million yen ($7 million) for a cell-processing center to support Takahashi before her trial was even approved. Two centers devoted to iPS cells are slated to be built with 2.2 billion yen ($22 million). The AFP reports the prime minister has set aside a breathtaking $1.18 billion, for iPS-cell work. Yamanaka has told Nature that the Japanese government seems to be “telling us to rush iPS cell-related technologies to patients as quickly as possible.”

Robert Lanza, CSO of Advanced Cell Technology, might once have been the logical bet to be first to the clinic with iPS cells. Unlike Takahashi, he has three ES cell trials under his belt, and has started talks with the FDA about transplanting iPS cell-derived platelets, but his iPS proposal is taking longer. Lanza bitterly noted, not without justification, “We don’t have the prime minister and emperor to speed things along for us.”

Since 2007, the year that Yamanaka reported the derivation of iPS cells from adult cells, Japan has focused on iPS cells. Yamanaka showed that increasing the expression of four genes could change limited adult human cells into potent, embryonic-like cells. “At Yamanaka’s institute alone, there are at least 20 teams focusing on iPS cells now,” Sipp says. There are teams at Riken, the Universities of Tokyo and Keio, and others. “A lot is happening here.” In fact, the Center for IPS Cell Research and Application was created expressly for Yamanaka.

Takahashi has reported part of the design of her clinical trial at scientific meetings. She told the International Society for Stem Cell Research in June 2012 she had created iPS-cell derived retinal pigment epithelial (RPE) cells for transplantation. RPE cells lie behind the photoreceptors in the retina, and the photoreceptors have their ends embedded into the RPE. The RPE cells replenish and nourish the photoreceptors, and without the RPE cells, the photoreceptors die from the damage incurred by exposure to light.

Retinal Pigmented Epithelium

Death of the RPE cells cause eventual death of photoreceptors and that results in blindness. At the International Society for Stem Cell Research conference, Takahashi reported her that her iPS cell-derived RPEs possess proper structure and gene expression. They also do not produce tumors when transplanted into mice, and survive at least six months when transplanted into the retinas of monkeys. The vision of these animals, however, was not tested. She did note that some AMD patients’ sight improves when RPE cells are moved from the eye’s periphery to its center.

Retinal pigment epithelial cells derived from iPS cells.
Retinal pigment epithelial cells derived from iPS cells.

Takahashi has published many iPS and ES cell papers. These papers include two papers with Yamanaka: one on creating retinal cells from iPS cells, and one on creating safe iPS cells. However she has not published trial details, which is not required, but such a landmark trial should be transparent, as argued by many stem cell experts.

Still, according to Sipp, Takahashi has submitted a relevant paper to a top journal for review, which shows that this clinical trial is purely a determination of the safety of the procedure. Lanza has reported his trials in the journal The Lancet, and similar, but small, trials are doing well. His three ES cell trials treated Stargardt’s macular dystrophy and Age-related Macular Degeneration. Lanza’s trial, however, treated “dry” macular degeneration, while Takahashi’s trial will treat “wet” Age-related Macular Degeneration, which is good news for Takahashi.

Paul Knoepfler, a UC Davis stem cell scientist who runs a widely read blog site, has written that the ministry overseeing Takahashi’s trial will reportedly monitor some key factors: gene sequencing and tumorigenicity. But Knoepfler, like others, would like to see more details.

The Japanese Health Ministry and the US FDA recently agreed to devise a joint regulatory framework for retinal iPS cell clinical trials, which will come on line 2015. Takahashi’s trial is set for 2014.