High doses of antioxidant supplements induce stem cell genetic abnormalities
by ilene - May 4th, 2010 7:19 pm
This is interesting, and important if you’re taking lots of supplements thinking that the more antioxidants you take, the longer you’ll live. Research is providing plenty of evidence that it doesn’t work so simply, while supplements fail to act according to the logical prevailing theory. Here’s another piece. – Ilene
High doses of antioxidant supplements induce stem cell genetic abnormalities
Courtesy of David Granovsky, in SCIENCE & STEM CELLS
High doses of antioxidant supplements induce stem cell genetic abnormalities
High doses of antioxidant nutritional supplements, such as vitamins C and E, can increase genetic abnormalities in cells, which may predispose supplement-takers to developing cancer, according to a new study from the Cedars-Sinai Heart Institute.
The study, led by Eduardo Marbán, M.D., Ph.D., director of the Cedars-Sinai Heart Institute, was published online today in the medical journal Stem Cells. The study also will appear in the journal’s July printed edition.
Marbán and his team accidentally discovered the danger of excessive antioxidant doses while seeking a way to reduce the genetic abnormalities that occurred naturally when the scientists sought to multiply human cardiac stem cells.
Marbán stressed that the study’s finding applies only to excessive nutritional supplements and not to foods that are rich in antioxidants, such as milk, oranges, blueberries and peanuts. In recent years, multiple studies have touted the benefits of foods rich in antioxidants.
“Taking one multivitamin daily is fine, but a lot of people take way too much because they think if a little is good, a lot must be better,” said Marbán, who is also the Mark Siegel Family Professor at Cedars-Sinai. “That is just not the case. 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.”
In laboratories, stem cells are often grown in a Petri dish culture than is composed of 20 percent oxygen, whereas cells growing inside human tissue are exposed to just 3 to 5 percent oxygen. But Marbán’s team of researchers became frustrated because the higher concentration of oxygen in lab-grown stem cells resulted in 9 percent of the cells being rejected because of genetic abnormalities.
“We sought to counter that oxidation problem by adding high doses of antioxidants directly to…
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A Stem-Cell Discovery Could Help Diabetics
by ilene - September 2nd, 2009 2:34 pm
A Stem-Cell Discovery Could Help Diabetics
By Alice Park, courtesy of TIME
Researchers are inching ever closer to bringing the latest stem-cell technologies from bench to bedside — and are, in the process, learning more about some diseases that long have remained medical black boxes.
This week, scientists at the Harvard Stem Cell Institute (HSCI) reported the first success in generating new populations of insulin-producing cells using skin cells of Type 1 diabetes patients. The achievement involved the newer embryo-free technique for generating stem cells, and marked the first step toward building a treatment that could one day replace a patient’s faulty insulin-making cells with healthy, functioning ones.
The experiment, published in the Proceedings of the National Academy of Sciences, also provided the first good model — in a petri dish — of how Type 1 diabetes develops, giving scientists a peek at what goes wrong in patients affected by the disease. Such knowledge could lead to not only new stem-cell-based treatments, but also novel drug therapies that might improve the symptoms of the disease.
Douglas Melton, co-director of HSCI, and his team took skin cells from two Type 1 diabetes patients, exposed the cells to a cocktail of three genes that converted them back to an embryonic state — which are referred to as pluripotent stem cells — then instructed the newly reborn cells to grow into beta cells, the cells in the pancreas that secrete insulin. In Type 1 diabetes, these beta cells no longer work to break down the glucose that floods the body after each meal, leading to blood-sugar spikes that can damage the kidneys and heart.
To test whether their lab-made cells could function like normal beta cells, Melton’s group exposed them to glucose in a dish. When sugar levels were high, the cells produced more of a protein that beta cells release when they break down sugar; when glucose levels were low, the protein levels were low as well.
"These cells represent the newest model of diabetes for humans," says Melton. "We have a lot of good models of Type 1 diabetes in the mouse, but everything that we have learned from them has failed in the clinic. Now we have a chance at figuring out how humans get the disease."…
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Philip R. Davis is a founder Phil's Stock World, a stock and options trading site that teaches the art of options trading to newcomers and devises advanced strategies for expert traders...
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