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SAN FRANCISCO - Research showing that bald mice can grow hair after being implanted with a type of stem cell could lead to a cure for baldness, a group of scientists says.
The project marks the first time that "blank slate" stem cells were able to induce hair growth, said Dr. George Cotsarelis, a University of Pennsylvania dermatologist and co-author of a study released Sunday on the Web site of the journal Nature Biotechnology, www.nature.com/nbt "We've shown for the first time these cells have the ability to generate hair when taken from one animal and put into another," Cotsarelis said in a telephone interview. "You can envision a process of isolating existing stem cells and re-implanting them in the areas where guys are bald."
The study confirms what scientists suspected for years: hair follicles contain "blank slate" stem cells - not the same as controversial embryonic stem cells - that give most humans a full head of hair for life.
Biologists who study the regenerative qualities of hair said the new study is an important breakthrough. But they cautioned that a baldness cure is still some years away."Good' cholesterol viewed as less than a cure-all
For years, doctors have been saying that to prevent heart disease, patients should pay attention to both the so-called bad cholesterol, or LDL, and the good cholesterol, or HDL. The good, they said, can counteract the bad.
But now new research has called into question whether high levels of good cholesterol are always good and, when they are beneficial, how much.
While some heart experts are not ready to change their treatment advice, others have concluded that HDL should play a minor role in deciding whether to prescribe cholesterol-lowering drugs.
The good cholesterol hypothesis comes from studies like the Framingham Heart Study that followed thousands of people for years to see who developed heart disease. The studies showed that if two people had the same levels of bad cholesterol, LDL, but different levels of good cholesterol, HDL, the one with more HDL was less likely to have heart disease.
Researchers examining the biochemistry of the two molecules learned that they have opposite roles. Both transport cholesterol, but they carry it in opposite directions.
LDL ferries cholesterol to coronary arteries, where it imbeds and participates in the growth of plaque. HDL trucks cholesterol away from arteries, taking it to the liver where it is disposed of.
So with epidemiological studies showing reduced heart disease risk and science showing why, it would seem the picture was clear: the more HDL the better. One HDL molecule might even cancel one of LDL.
Too simplistic, says Dr. Daniel Rader, a cholesterol researcher at the University of Pennsylvania School of Medicine. "Yes, high HDL is generally a good thing, but it doesn't mean it is so powerful that it creates a total immunity to heart disease," he said. "I really don't feel that treatment for high LDL should be withheld just because the HDL level is high."