Oxidative Levels Key in Stem Cell Generation

LOS ANGELESA balance of free radicals and antioxidants is critical when multiplying stem cells to avoid genetic mutations in DNA, according to an in vitro study published in Stem Cells (ePub 4 May 2010; DOI:10.1002/stem.438). Researchers from Cedars-Sinai Heart Institute, led by its director Eduardo Marbán, M.D., Ph.D., were examining ways to possibly prevent cytogenetic abnormalities in cardiac stem cells that occur when they are multiplied for use in regenerative therapies, possibly due to oxidative damage. Stem cells in laboratories are often grown in cultures composed of 20 percent oxygen, versus cells growing in human tissue that are exposed to 3 to 5 percent oxygen. As a possible solution, the researchers added to the cells a 100- to 1 million-fold diluted proprietary antioxidant blend for cell culture (supplied by Sigma-Aldrich) or an antioxidant blend made in the laboratory with 100 M each of L-ascorbate, L-glutathione and -tocopherol acetate (0.1 to 1,000 dilution).

Addition of antioxidants to the medium increased the incidence of chromosomal damage, even as intracellular levels of reactive oxygen species were significantly decreased. There appeared to be a dose-dependent response whereby antioxidants at low concentrations suppressed DNA damage, but potentiated such damage at higher concentrations, possibly by decreasing cellular levels of DNA repair enzymes.

In a statement, Marbán said the results of this study suggest there may still be a place for a multivitamin, but mega doses of antioxidants could be problematic. He said, If you are taking 10 or 100 times the amount in a daily multivitamin, you may be predisposing your cells to developing cancer, therefore doing yourself more harm than good.

However, drawing such a conclusion from this study is misguided, according to Douglas Duffy MacKay, N.D., vice president of scientific and regulatory affairs, Council for Responsible Nutrition (CRN). He said: This study does great work to explore optimal conditions for growing stem cells outside of the human body, in particular stem cells taken from cardiac transplant patients who are immune suppressed to avoid transplant rejection. They are looking for a sweet spot to introduce antioxidants to support growth in an environment outside the body. What they found was that extremely high amounts of antioxidants added to a petri dish culture of immune suppressed stem cells with an oxygen level four times what is found inside the human body is not the optimal growing condition. But hes jumping to conclusions about the effects of antioxidant consumption in the body. We all agree there is an optimal level of antioxidant consumption, and the 1 to 2 percent of adults who are consuming the 5 to 13 servings a day of fruits and vegetables are likely meeting that optimal level. But that is very rare, so supplements are a prudent way for most individuals to meet their needs.  Its really about prevention.