Posts Tagged ‘embryonic stem cells’
The First Trial of an Embryonic Stem Cell Treatment for Blindness Begins in California
The retinal cells were grown from embryonic stem cells--those controversial (because of their source) biological building blocks with the ability to turn into any human tissue. This latest effort is among the first in the world to use embryonic stem cells as treatment. Last year another biotech company called Geron began a small trial using stem cells to treat spinal cord damage (the jury is still out on that one).
The retinal treatment is being carried out at the University of California but the science comes from Massachusetts-based Advanced Cell Technology, which recently received approval from the FDA to test a treatment aimed at replacing the retinal pigment epithelial cells destroyed by macular degeneration. That destruction eventually leads to blindness as photoreceptors die off.
To do this, Advanced Cell grows brand new retinal cells in the lab from embryonic stem cells and then implants them directly into the retina, where researchers hope they will take root and stop the degeneration process. If it works, Advanced Cell could be onto something big. Macular degeneration affects some 10 million people in the U.S. alone and is a prevalent cause of blindness in older people.
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‘Retina in a Dish’ is the Most Complex Tissue Ever Engineered in the Lab
If the breakthrough can be adapted to work with human cells, it could provide a retina that is safe for transplantation into human eyes, providing a potential cure for many kinds of blindness. That’s still years away, but in the meantime the lab-grown mouse tissue could provide researchers with a wealth of information on eye diseases and potential treatments for them.
The tissue developed at Kobe’s RIKEN Center for Developmental Biology is more than just a retina--it’s an entire optic cup, the two-layered organ that is composed of both the retina and an outer layer of pigmented cells that provide nutrients and support the retina and the light-sensitive cells that conduct information to the brain.
To create it in the lab, they simply put mouse embryonic stem cells in a cocktail of nutrients and proteins that pushed the cells into developing into retinal cells. But critically they also added a protein gel to support the cells and keep their structure together. At first, the stem cells simply transformed into clusters of early retinal cells, but given time they slowly generated a fully-formed optic cup just as they would in a natural embryo.
What’s unclear is whether or not this lab-grown version would actually transmit the proper impulses to a mouse brain, and naturally that’s what the next phase of research aims to find out. If so, the leap to generating human retinal tissues from human embryonic stem cells is not prohibitively large.
In the meantime, a wealth of new retinal tissue in the lab gives researchers an opportunity to identify the molecular defects that cause different eye diseases and to test potential treatments. But further, it could inform the larger pursuit of better engineered tissues. A retina in a dish proves that given the right prodding, embryonic stem cells can spontaneously generate even the body’s most complex tissues.
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Using Stem Cells, Scientists Re-Create Memory Neurons That Succumb to Alzheimer’s
Jack Kessler, chairman of neurology at Northwestern University's Feinberg School of Medicine in Chicago, cautions that the research is , but it puts scientists on a path toward understanding how to treat memory loss, one of the most debilitating symptoms of Alzheimer’s.
Led by researcher Christopher Bissonnette, who was drawn to Alzheimer’s research after losing his grandfather to the disease, the Northwestern team coaxed embryonic stem cells into becoming basal forebrain cholinergic neurons, or BFC cells. The neurons facilitate the retrieval of memories, .
Embryonic stem cells, which are derived from embryos created for in-vitro fertilization, can be induced to turn into any kind of cell. The team also tried it with skin cells, turning them into induced pluripotent stem cells, but most of the work focused on the embryonic cells. Bissonnette’s team spent six years testing millions of cells before they figured out the gene sequence required to turn them into BFC neurons, according to the .
They implanted the replacement cells in mice, and the cells appeared to work in the same way as the mice’s natural BFC cells, Health Day says.
BFC neurons are thought to be the earliest cells lost to Alzheimer’s disease, which usually first appears as . Brain activity is altered as cells cease functioning and die; eventually, patients lose the ability to communicate or respond to their environment.
The Northwestern group is not the first to turn stem cells or , but they’re the first to turn them into specific neurons associated with learning.
Even if the stem cells could be implanted in Alzheimer’s patients, it doesn’t attack the disease directly. Scientists are still unsure what causes Alzheimer’s to develop. But it could be combined with other treatments, and it might help patients in the earliest stages of the disease, the Northwestern team said.
The research, funded by the National Institutes of Health, is reported the March 4 issue of Stem Cells.
In First Stem Cell Stroke Trial, Scottish Patient Has Embryonic Stem Cells Injected Into His Brain
Doctors at Glasgow's Southern General Hospital will conduct periodic MRI scans to look for repairs or changes in areas of the patient’s brain damaged by stroke. The trial, called Pilot Investigation of Stem Cells in Stroke (PISCES), is designed to check the procedure’s safety, but any signs of physical improvement would be a major leap in neural medicine.
Before the surgery, researchers at UK company ReNeuron grew the stem cells into neural stem cells. the company obtained the cells from a donated 12-week-old human fetus from the U.S. (An embryo becomes a fetus about eight weeks after fertilization.)
The procedure was initially approved last year.
Keith Muir of the University of Glasgow, the lead researcher on the trial, said some of the injected neural stem cells would grow into neurons. But they could prove even more versatile — earlier studies in rats showed that the stem cells triggered a wide variety of cell development, including new brain blood vessels.
During the next year, as many as 12 other patients will get progressively higher doses of stem cell injections, reaching as many as 20 million cells, according to Muir.
Stem cells are valuable because they can become any type of cell in the body, but are controversial because embryonic stem cells require the destruction of human embryos. The National Institutes of Health is embroiled in a over whether its federally funded researchers can study human embryonic stem cells; for now, , but the future is in the hands of the courts.
Doctors in Russia, China and other nations offer to patients with a host of maladies, but the treatments are often poorly regulated or not at all.
Despite the controversies, the Scottish trial is the second notable embryonic stem cell implantation procedure in as many months. After years of delays, the first American embryonic stem cell therapy for spinal injuries started last month, when a spinal patient received a stem cell injection into the spinal cord. Again, the study’s goal is to prove the treatment is safe, but doctors hope the paralyzed patient will see some physical improvement. As many as nine other patients may join that study.
In August, an Iraq war veteran became the first recipient of an adult stem cell implant, also to treat a spinal injury.
NIH Research Chief: Shut Down Human Embryonic Stem Cell Experiments Immediately
The move comes after an injunction barring federal funding for stem cell research
The move, reported in ScienceInsider, comes on the heels of a that blocked the use of federal funds to study new embryonic stem cell lines. A judge said President Obama's 2009 executive order violates a federal law barring the use of federal funds to destroy embryos.
Scientists are seething over today's ruling, announced in a memo from NIH intramural research chief Michael Gottesman. According to ScienceInsider, Gottesman said: "The injunction ... is applicable to the use of human embryonic stem cells in intramural research projects. In light of this determination, effective today, intramural scientists who use human ES cell lines should initiate procedures to terminate these projects. Procedures that will conserve and protect the research resources should be followed."
So far, outside labs are unaffected -- intramural means researchers in labs on the NIH campus, while extramural refers to researchers at other institutions who receive NIH grants.
The agency has eight research projects that use human embryonic stem cells, most if not all of which use lines approved under the Bush Administration back in 2001.
Under Obama's rules, federal money could be used for research on cell lines in addition to the ones Bush greenlighted nine years ago. After the injunction, scientists were hopeful they could still use the original cell lines -- but now the future looks murky.
ScienceInsider says the Department of Justice might ask the courts to delay the injunction, which could allow experiments to continue uninterrupted.
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Federal Judge Halts Obama’s New Embryonic Stem Cell Policy, Leaving Research in Limbo
The ruling, according to Chief Judge Royce C. Lamberth of the Federal District Court for D.C., should return the federal policy to the "status quo," an ambiguous statement that some understand as a return to the Bush administration's policy of limiting federally funded research to work on the 21 embryonic stem cell lines already created in 2001. But some scientists worry that the ruling may condemn all embryonic stem cell research illegal, including research that was allowed under the Bush policy.
President Obama moved early in his presidency to expand the kinds of stem cell research that can receive federal dollars. The government still cannot fund research that directly destroyed embyos, but under Obama's rules federal money could fund research on cell lines outside of those original 21 the Bush rules had limited researchers to. So if private financing could be used to obtain or create new stem cells (usually from fertility clinics and with consent of unpaid donors), federal funds could then be used to conduct research on those cells.
Yesterday's ruling strikes down the line between embryonic destruction and later work on cells resulting from that destruction. What's unclear is how far it goes. Some scientists worry that the ruling may make illegal even work that was allowed under the Bush policy. Some think that if they continue the research they were doing yesterday they may be in violation of the law, while others have interpreted it to mean that research may continue but the National Institutes of Health must use the Bush-era guidelines for federal grants going forward.
In the meantime, some researchers have simply told their labs not to use anything in their research that was paid for with federal dollars until Department of Justice lawyers figured out exactly what the ruling means. More on this as it develops, but for the time being sensitive stem cell experiments nationwide appear to be in a state of limbo. More details on the legal minutiae are available through the NYT link below.
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