A couple of releases culled from EurekAlert! in the past day or two are illustrative of the direction and progress of one major branch of stem cell based regenerative medicine at present. One the one hand is the exploration of how it is that transplanted stem cells can produce regeneration above and beyond what the body will accomplish on its own. On the other hand, there is a continual identification of new stem cell populations throughout the body, and the search for controlling signals and mechanisms that could be used to enhance their innate regenerative capacities.

Stem cells can improve memory after brain injury:

They found that only about 4 percent of [transplanted stem cells] turned into neurons, indicating the stem cells were not improving memory simply by replacing the dead brain cells. In the healthy mice, the stem cells migrated throughout the brain, but in the mice with neuronal loss, the cells congregated in the hippocampus, the area of the injury. Interestingly, mice that had been treated with stem cells had more neurons four months after the transplantation than mice that had not been treated.

“We know that very few of the cells are becoming neurons, so we think that the stem cells are instead enhancing the local brain microenvironment,” Blurton-Jones said. “We have evidence suggesting that the stem cells provide support to vulnerable and injured neurons, keeping them alive and functional by making beneficial proteins called neurotrophins.”

If supplemental neurotrophins are in fact at the root of memory enhancement, scientists could try to create a drug that enhances the release or production of these proteins. Scientists then could spend less time coaxing stem cells to turn into other types of cells, at least as it relates to memory research.

Jefferson researchers find stem cells in degenerating spinal discs, potential for repair:

Orthopedic researchers at Jefferson Medical College have for the first time found stem cells in the intervertebral discs of the human spine, suggesting that such cells might someday be used to help repair degenerating discs and remedy lower back and neck pain. ...

According to Dr. Shapiro, as the discs in the spine degenerate, cells are lost and the ability to produce water-binding molecules called proteoglycans is decreased. The water absorbs forces on the spine, essentially serving as shock absorbers. Losing proteoglycans can result in damage to the disc, and sometimes, pain.

...

Shapiro notes that other researchers have taken bone marrow stem cells and have made new bone, cartilage and fat tissue. “Our next step is to activate these disc stem cells and get them to repopulate the disc and make proteoglycans and restore the water-binding,

The scientists theorize that because the stem cells exist in the degenerate disk, there may be molecules that are blocking stem cell activity. “Something is inhibiting the disc repair process,” says Dr. Shapiro. Drs. Shapiro and Risbud agree that “new studies are needed to discover the nature of such inhibitory molecules” and to find ways to block their activities, promoting natural healing.

Regeneration is not rejuvenation - but it will be big improvement over the present capabilities of medical technology.

Posted by Reason at November 1, 2007 2:30 PM | TrackBack (0)