The possibility of tissue and organ regeneration through the use of adult stem cells with the pluripotent properties of embryonic stem cells has advanced significantly, for men at least, with their creation (in a mouse model) from cells abundant in the testes.
We have also found a way to cultivate adult stem cells prolifically in the lab, another boon for research and therapies such as a fetal (not embryonic) stem cell therapy for Batten’s disease, for which a clinical trial now getting underway will mark the first time stem cells are injected into the human brain. Another potential alternative to embryonic stem cells are placental stem cells. And while another regenerative cure for spinal cord injuries has worked in rats, one for damaged heart muscle has not worked so well in people. It appears we will need to learn much more about the biology involved if stem cell therapies are to achieve their suspected potential. Russia is apparently saying “To heck with the biology: Let’s just do it and see what happens.” Russian free marketers aspire to heights their American comrades can only dream about, in developing a cottage stem cell therapy industry with little to no government oversight. It will likely give Russia a lead in the science and business of treating patients, including “medical tourists,” even as it runs risks of causing suffering and harm. Stem cells are not the whole of regenerative medicine: Tissue engineering is another part. Tissue engineered bladders implanted between four and six years ago are so far working well in seven young recipients. More trials are planned, and the researchers who achieved this feat are turning their attention to other tissues and organs. |
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ESCs from Testes
German scientists have “easily” retrieved and transformed precursor stem cells (spermatogonial cells) found in mouse testes into “what appear to be” embryonic stem cells (ESCs), reports Rick Weiss in the Washington Post . If similar precursor cells exist in men and could be turned into ESCs, they could be used to create rejectionless lab-grown replacement tissues and organs in individual males. This, notes Weiss, “is not the first claimed discovery of an alternative source of embryonic stem cells” (menstrual blood, bone marrow, and fat are among the others) but it is a significant advance because the testes cells were more numerous, easier to find, and “passed every gold-standard test used today to prove their equivalence to embryonic stem cells.” The researchers have already used the testes cells to grow liver, muscle, pancreas, nerve, and various kinds of heart cells “which spontaneously coalesced in a lab dish and started beating in synchrony.” If egg precursor cells similar to the sperm-producing cells exist in women’s ovaries, they may be amenable to the same manipulation. Boost for Adult Stem Cell Therapies A new method of cultivating bone marrow-derived blood stem cells could make bone marrow transplants available to more patients, reports Gareth Cook in the Boston Globe . The innovation is a cocktail of growth factors, which multiplies the stem cells up to thirtyfold. It was developed using mice, but must now be replicated with humans. The discovery could also be used to multiply umbilical cord blood for use as an alternative source of stem cells for patients needing bone marrow transplants. Further, it could facilitate adult stem-cell research, since it has hitherto been difficult to maintain viable samples for long periods. Oregon researchers are recruiting patients for a Phase 1 (safety) clinical trial of a fetal stem cell therapy with Batten disease, a rare but brutal brain disease that leaves its infant and child victims blind, speechless, and paralyzed before they die, reports William McCall for the Associated Press. The stem cells — derived from fetal tissue, not embryos — will be injected into the brain. The therapy showed promise in animal tests. A US biotechnology startup called Plureon Corporation has developed pluripotent placental stem cells PSCs to regenerate tissues and organs for diseased patients. The cells are isolated from the placental tissue ejected from mothers as “afterbirth” and are therefore free of the ethical issues involving embryonic stem cells. Plureon is keeping its plans close to its chest but hints that something is in the offing, possibly (on the basis of investments from certain parties) involving diabetes and/or a “Keratin Bioceramic Antibiotic Putty for Bone Regeneration” compound for treating soldiers in combat. Plureon also has a relationship with Cryo-Cell, which collects and stores stem cells from umbilical cords. University of Louisville researchers have formed a company to develop stem cell therapies for spinal cord injuries, multiple sclerosis, Parkinson’s disease, and other nerve disorders, though the therapies are at least three years away, reports Laura Unger in the Courier-Journal . This followed successful studies in which rats, after having their spinal cords damaged in such a way that they lost the use of their right paws, were injected with a gel containing stem cells first biopsied from the olfactory neurosensory epithelium in the noses of adult human volunteers then coaxed in the lab into becoming neurons. Twelve weeks after the injury, the treated rats were using both paws to walk across a rope and climb to the top of a cylinder. This has obvious potential as a rejectionless and non-ethically-contentious therapy for a wide variety of conditions, since it has been shown that the cells can be coaxed into becoming other types of cell, not just nerve cells. Even so, the lead researcher still supports research on embryonic stem cells, if only as a foundation to help understand adult stem cells. An experimental stem cell therapy for heart attack patients has not lived up to its early promise, though the game is far from over. The treatment consisted of injecting a hormone (GCSF) to induce the patient’s bone marrow to send blood-making (stem) cells out into the bloodstream where they would migrate to the heart and transform themselves into muscle cells. However, promising results in animal models and several small-scale human trials did not translate into success for a major trial in Germany involving a large number of patients. Those given GCSF injections showed neither improved heart function nor a reduction in scar tissue. It appears the earlier trials were poorly designed. While other variations of the treatment could be tested, “our data do not prompt optimism and are not supportive of the application of stem cell therapy in patients with heart attacks,” a member of the German research team is quoted as saying. More needs to be known about the basic biology of stem cells before going to new clinical trials, she said. The quotes come from a New York Times article by Nicholas Wade, who reports (citing a review in the journal Circulation) that “Many of the benefits seen from injecting various kinds of cells into stricken heart muscle over the last 10 years have probably been caused not by true regeneration of the heart but by unexpected side effects like the cell’s secretion of hormones.” For about US$10,000, Russian beauty clinics are taking stem cells from clients’ stomach fat and injecting the cells into the clients’ faces, to make them younger, healthier, and longer-lived. Speaking from direct personal experience as a self-experimenter, the clinic’s director told the BBC “The person blossoms, their skin colour improves, they get more energy, their hair and nails become better.” He himself has “no diseases at all, not even a cold, I have a really good immune system…. I’m sure it’s safe. I think Russia can become a pioneer in using stem cells.” The head of Russia’s Public Health Agency is alarmed and the government has already closed down several beauty clinics offering stem cell treatments. “But,” notes the BBC, “it has also issued licences to two [apparently, medical] clinics that are developing medical uses for the cells.” One of them is injecting stem cells into the central nervous system of paralyzed patients, including an American woman who has paid US$40,000 for the treatment. Lab-Grown Bladders Work in Humans Tissue-engineered bladders created from the cells of seven patients aged 4-19 with myelomeningocele, which causes urinary leakage and incontinence, and implanted in them between 1999 and 2004, have worked well so far, according to Wake Forest University Baptist Medical Center researchers. The bladders grow with the patient, and are expected to last a lifetime, with no chance of rejection since the cells come from the patient. Urinary incontinence and other complications improved or did not occur in any of the seven patients, Dr. Atala’s team reported. A larger clinical trial is planned to begin this year and another, which will include adults, in 2007. Standard treatment involves taking pieces of stomach or bowel to reconstruct a bladder, but it can lead to complications including adhesions, mucus secretion; and bladder stones. It is hoped the technique can eventually be used to grow other tissues — skin, bone and cartilage have already been engineered — and other organs. Some 80 researchers at Wake Forest are working to build new hearts, livers, kidneys, pancreases, nerves, and other tissues. |