Adult Human Brain Stem Cells Reproduce In Vitro
Brain stem cells recovered from living adult human tissue have successfully reproduced in vitro at the University of Tennessee- health science center. Additional research from the same laboratory also shows successful isolation and cultivation of mouse brain stem cells recovered as long as five to seven days postmortem. Scheduled this month for publication in a special issue of Experimental Neurology, these findings could provide a possible alternative to the research use of embryonic stem cells, an approach in stem cell biology and its possible therapeutic use that raises controversial ethical issues.
Dr. Valery G. Kukekov of UT-Memphis and Methodist Healthcare of
Memphis, is lead author on the paper detailing the growing of adult
brain stem cells recovered from surgical specimens taken from
patients ranging in age from 24 to 57. The paper is titled
"Multipotent Stem/Progenitor Cells with Similar Properties Arise from
Two Neurogenic Regions of Adult Human Brain."
Dr. Eric D. Laywell of UT-Memphis is lead author of the paper
detailing the growing of brain stem cells recovered from mouse
cadavers five to seven days postmortem. Laywell's paper is titled
"Multipotent Neurospheres Can Be Derived from Forebrain Subependymal
Zone and Spinal Cord of Adult Mice after Protracted Postmortem Intervals."
The work is from the laboratory of Dr. Dennis A. Steindler, UT- professor of neurobiology and a co-author on both papers. Describing the work, Steindler said, "This new era of applying knowledge gained from genetics, molecular, cellular and developmental biology is much more than just the discussion of the ethical issues surrounding embryonic and fetal cell research, and the controversy over cloning animals and human beings.
"This new research showing that stem/progenitor cells from adult
brains can be expanded in culture (ex vivo) offers hope for future studies which could someday lead to autologous stem cell transplants for self-repair regenerative approaches," said Steindler. "It now is possible to think about using our own population of stem cells because it appears they survive well into mature adulthood."
Kukekov's research recovered cells from the hippocampus and the subependymal zone (SEZ). The SEZ is a remnant left over from the fetal/baby brain region remaining in the adult brain that surrounds the fluid-filled spaces called ventricles.
Kukekov said, "These results are encouraging because it means that even senior persons have these cells. This gives us the opportunity in the future, as the research expands, to take a small biopsy specimen from a diseased person, grow the necessary cells and then transplant them back to the same person."
Kukekov said the research team is now working on describing the molecular biologic characteristics of the cultured cells. "We cannot move forward and be successful in experiments with propagation without knowing how genes are expressed in the process and what molecular events are occurring."
Laywell's work with cadaveric mice successfully isolated and recovered stem cells up to five to seven days after death when the mice were kept at 4 degrees C. The cells were retrieved from the adult mouse spinal cord and forebrain SEZ. Using the culturing technique developed by Kukekov, the mouse cells grew and multiplied and gave rise to both neurons and glia.
Laywell said the number of surviving cells drops off rapidly with time, but since they appear to be stem cells, only one is needed to multiply in culture.
Laywell said, "Bone marrow stem cells have been repopulated from cadavers, so it seems to be a property of stem cells in general that they can survive in conditions that other cells can't."
Laywell's paper includes a single human-cadaver unpublished observation which produced results similar to those found with the mice.
The research is an international collaborative effort with coinvestigators in Bonn, Germany; Japan, and Memphis. The adult brain tissue was provided with patient consent by Dr. Keith G. Davies, a neurosurgeon with UT-Memphis and Semmes-Murphey Clinic and a coauthor on the adult cell paper.
Kukekov's work was funded by the Methodist/Le Bonheur Healthcare Foundation.
Laywell's work was funded by the Spinal Cord Research Foundation of the Paralyzed Veterans of America (PVA). Steindler's work was funded by the National Institutes of Health (NIH). The Daimler-Benz Foundation funded the work of co-author Dr. Bjorn Scheffler. - By Claire Lowry
[Contact: Claire Lowry]
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