Ring of protection. In experiments, myelin produced by injected human neural stem cells (green) formed protective sleeves around the nerve fibers in mouse brains (red).
Credit: RIKEN CDB; StemCells Inc.
Posted on 06/18/2012 6:49:31 PM PDT by neverdem
YOKOHAMA, JAPAN—For more than a decade, stem cell therapies have been touted as offering hope for those suffering from genetic and degenerative diseases. The promise took another step toward reality last week with announcements here at the annual meeting of the International Society for Stem Cell Research (ISSCR) that two groups are moving forward with human clinical research, one focusing on a rare genetic neurological disease and the other for the loss of vision in the elderly.
StemCells Inc. of Newark, California, reported encouraging results of an initial human trial using human neural stem cells to treat Pelizaeus-Merzbacher disease (PMD). PMD is a progressive and fatal disorder in which a genetic mutation inhibits the normal growth of myelin, a protective material that envelopes nerve fibers in the brain. Without myelin, nerve signals are lost, and the patient, usually an infant, suffers degenerating motor coordination and other neurological symptoms. In her presentation, Ann Tsukamoto, StemCells' vice president for research, said the company chose to test its neural stem cell approach on PMD because there is currently no treatment for the condition and a diagnosis can be confirmed by genetic testing and magnetic resonance imaging. "This creates an opportunity for early intervention when it can best help."
The company has created banks of highly purified neural stem cells that are isolated from adult neural tissue. Injected into rodents, the cells don't form tumors; rather, they migrate through the animals' brains, where they differentiate into various types of neural cells including the cells that create the myelin that protects nerve fibers. When neural stem stems were injected into in mice, they showed "robust engraftment and migration, the formation of new myelin," Tsukamoto said.
The company has now sponsored an initial safety trial of the strategy in four infants with PMD. In each patient, researchers at University of California, San Francisco, transplanted 75 million neural stem cells into each of four sites in the brain and followed that with immunosuppressive therapy so the recipient wouldn't reject the foreign cells. No safety concerns arose during the trial, Tsukamoto reported. Moreover, magnetic resonance imaging taken 18 months later indicated the formation of new myelin around axons and clinical observations of the treated patients indicated that their motor functions remained stable or enjoyed modest gains. The company is now planning larger trials. Tsukamoto says that if the therapy proves efficacious it could lead to neural stem cell treatments for multiple sclerosis, cerebral palsy, and Alzheimer's disease.
In a second talk at the meeting, stem cell researcher Masayo Takahashi of the RIKEN Center for Developmental Biology in Kobe reported on progress in her group's preclinical work targeting wet-type age-related macular degeneration (AMD). In AMD, the retinal pigment epithelial (RPE) cells that support the cells in the eye that detect light wear out, and there is also the growth of abnormal, leaky blood vessels below the retina. These conditions lead to impaired vision in the central part of the eye. Her group's proposed strategy is to surgically remove the problematic blood vessels and replace the damaged RPE cells with new RPE cells derived from a patient's own cells. Using a process called cellular reprogramming, the researchers take a patient's skin cells, convert them into so-called induced pluripotent stem (iPS) cells, which can differentiate into all the cells within the human body. They then transform those iPS cells into RPE cells and form them into sheets in the lab. Since the iPS approach uses the patient's own cells, they avoid the need for immunosuppressive drugs.
The RPE cells generated by Takahashi's team show the characteristic structure and gene expression pattern of authentic human RPE cells. Injections of the cells into mice triggered no tumors, she also reported, and the cells survived for more than 6 months when transplanted into monkeys. The research team has not directly tested whether the transplanted RPE cells improved the animal's vision. But Takahashi notes that some people with AMD have had RPE cells transplanted from the periphery to the center of their eyes, improving their central vision. She hopes to have all necessary approvals for research with human subjects within a year.
Earlier this year, scientists at University of California, Los Angeles, and Advanced Cell Technology of Marlborough, Massachusetts, reported in The Lancet about the safe and successful use of RPE cells derived from human embryonic stem cells, rather than iPS cells, to treat a different type of AMD in a limited number of human patients. Takahashi predicts that in the future, selecting from different stem cell therapies will "depend on the target disease and the situation of the host."
The positive results reported in The Lancet paper and presented at ISSCR will help the field "gather momentum," says Fiona Watt, a stem cell researcher the Cancer Research UK Cambridge Research Institute. And George Daley, a stem cell scientist at Harvard Medical School in Boston, is even more upbeat. Noting the progress reported at this year's conference, he says, "Wait until next year in Boston," the site of the 2013 ISSCR meeting.
Nature News wrote that they used human embryonic stem cells, IIRC. Maybe something got lost in translation from Japanese.
Please cure type 1 diabetes.
Hopefully some will recognize the difference between using public tax money to fund the use of stem cells, and simply utilizing stem cells in research. There’s a world of difference between the two for many (most?) people.
Instead they are using pluripotential stem cell. Pluripetential stem cells are found in our red bone marrow. These stem cells becomes our red blood cells, white blood cells, and platelets.
It is interesting that they revert adult skin cells back to pluripotential stem cells. It would make it alot easier to cure some types of diseases without having to use bone marrow donors.
Are these Adult or Embryonic? Seems like Adult ones have been in prime time for years and years, and Embryonic ones have been all hype up till now...has Embryonic finally actually produced a benefit for all the hype and Californian tax money?
Placemarker
Thank you for clarification. I really wish the press would make the distinction...but of course it would reflect badly on the left's decade old claim that Republicans who did not want to support Embryonic research with tax money were standing in the way of impending miracle cures.
IIRC, the researchers used ‘adult’ skin cells, backed them up to the pluripotent stage found in embryonic development, then differentiated them forward to get the type they wanted.
These are stem cells taken from ADULT tissue, not embryonic, so they're not having the issue of tumor growth.
It appears that the article is talking about 2 separate trials with RPE from different sources.
I’m looking for an older article that I know I’ve seen, but there’s this one
http://dx.crossref.org/10.1371%2Fjournal.pone.0037342
Here’s an earlier publication by Takahashi on iPS retinal cells
http://jcs.biologists.org/content/122/17/3169.short
Yes it's 2 separate studies. The first used adult cells for the genetically caused myelin deficiency. At first I was saddened to see the use of immunosuppressants until I recalled the genetic deficiency.
The second used IPSC according to ScienceNOW, but Nature News implies embryonic stem cells.
But over the past four years, Sasai has used mouse embryonic stem cells to grow well-organized, three-dimensional cerebral-cortex1, pituitary-gland2 and optic-cup3 tissue. His latest result marks the first time that anyone has managed a similar feat using human cells.
Amazing!
Research done with adult stem cells has been much more successful than with embryonic. For one thing, malignant tumors were a big problem with embryonic but since it is not your own cells, the problems associated with rejection were also an issue. I once asked the head of a big stem cell research center why some people (politicians) continue to push for embryonic if science has shown unequivocally that adult cells are better. His response was that he thinks they just have too much time invested in the process to admit defeat now.
I would like to be on your stem cell ping list.
Thank you Neverdem,
Masayo Takahashi is mentioned both tn the ScienceNOW story and the Nature News' story linked in comment# 1. The blockquote in comment# 13 is from the Nature News' story. It strongly implies that human embryonic stem cells were used. So I don't know which source got it right. Is it ScienceNOW or Nature News? There's no mention of induced pluripotent stem cells in the Nature News' story.
But over the past four years, Sasai has used mouse embryonic stem cells to grow well-organized, three-dimensional cerebral-cortex1, pituitary-gland2 and optic-cup3 tissue. His latest result marks the first time that anyone has managed a similar feat using human cells.
Made sure to say the mouse stem cells were embryonic. Did not make sure to say the human cells were. While I am not a biologist, it seems the other article, is more explicit and technical...moreover the particular type of adult stem cells used had undergone a process to make them similar to embryonic stem cells in some important respects...which would explain the relevancy of mouse embryonic stem cells from the block quote from the less technical article.
When I wrote and offered on line that little book on stem cells and cloning back in 2000, I actually had people contacting me to ask questions designed to blur the morality, the right and wrongness. One contacted me via freepmail to ask if the brain were prevented from developing in an embryonic gestation, would I see the harvesting of such an organism's body parts as morally acceptable since the organism could never develop into a human child. The questionaer became insensed that I kept pointing back to the immoral intervention in order to create this 'less than human' fetus for harvesting. I had what purported to be a physician call me from OKlahoma (or was it Nebraska?) and offer a minor correction to my terminology, then start berating me for injecting morality into scientific issues! When I asked if the person I was talking to did therapeutic abortions, he slammed the phone down without answering.
The last ones to realize they are serving the father of lies who is a murderer from the start are the ones being deceived into the service. They will not allow Truth (read the God of the Bible) to threaten their comfy worldview, but that is precisely what The Holy Spirit does in order to bring one to a point of Salvation offered to them.
But my own layman's perception is that bad morals makes bad science. Not just in questions of medical ethics...but in terms of simple accuracy. I think its a harsh moral challenge to be willing to toss away years of hard work on a theory just because the evidence has turned against it...and then humbly adjust your thinking and carry on...especially when it means giving up the funding that might be politically motivated...and of course risking your career and reputation among other researchers who are less willing to follow the evidence....but thank God for those who were moral enough (as well as bright and hard working enough) to make real progress!
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