By Dave Andrusko

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I can't remember it ever crossing my mind that my expanding middle-age paunch might someday qualify as "liquid gold." But that's what it is, according to Dr. Michael Longaker, a co-author of an article in the Proceedings of the National Academy of Sciences, that says cells from human fat can be much more readily morphed into embryonic-like stem cells than can skin cells.

If you can't make hide nor hair of that paragraph, let me explain.

It's important, because the research is part of the growing body of evidence that shows we don't need to scavenge human embryos for their stem cells.

Dr. Shinya Yamanaka

Three years ago Shinya Yamanaka, of Kyoto University, made an amazing discovery. Human skin cells could be genetically reprogrammed (sent "back in time") to become what are known as induced pluripotent stem (iPS) cells. These are essentially indistinguishable from human embryonic stem cells.

If turning the clock back on an adult stem cell is proven to be successful, iPS cells might offer the promise of leapfrogging the rancorous debate over lethally extracting stem cells from human embryos.

The team at Stanford University's School of Medicine in California found that the stem cells found in human fat "are not as far along on the differentiation pathway, so they're easier to back up to an earlier state," Ning Sun, who led the study, said in a statement. "They are more embryonic-like than fibroblasts [skin], which take more effort to reprogram."

In practice that potentially means three important steps forward.

First, fat cells formed iPS cells at 20 times the rate that skin cells do.

Second, stem cells from fat can also be turned into iPS cells twice as quickly as fibroblast skin cells.

"Skin cells take three to six weeks to replicate in sufficient numbers to begin trying to reprogram them, while fat cells are plentiful from the start," Longaker told Bloomberg News. "Stem cell colonies begin to form 15 to 16 days after adding the genes when fat cells are used, compared with a month when using skin cells," the study found.

Third, the skin cell process "also often requires exposing the cells to mouse stem cells, called feeder cells, to nourish and guide the transformation," Scientific American reported. "This had raised alarms about the potential for contamination from mouse proteins."

Now that does not mean that every obstacle has been cleared. The team opted for the same formula Yamanaka did originally--using viruses to insert four genes into the cells they were trying to reprogram, according to Longaker, a plastic surgeon. (The fat cells were liposuctioned from four of Longaker's middle-aged patients.)

But using viruses have been associated with an increased risk of tumor formation, because some genetic remnant is left behind. This has prompted a flurry of activity to find new "delivery" systems, some of which show great promise.

I'm sure there are still others, but the last option I read about came from a team at the University of Wisconsin led by James Thomson. Thomson used a plasmid, described in the accounts as a "circle of DNA." The plasmid is biodegradable, so to speak. It disappears naturally.

What made Thomson's research so significant is his technique does not leave behind minute traces of added DNA. Thomson was the first to show that this plasmid technique works in human cells.

So while other researchers are dealing with addressing delivery concerns, this latest research dealt primarily with speed and efficiency.

It is very much worth remembering, however, that as much interest as there's been in iPS cells that adult stem cells used directly from that same liposuctioned fat are already in clinical trials to treat heart damage, cartilage repair, and other conditions.

Adult stem cells from sources like umbilical cords and bone marrow, as well as adult stem cells from fat, do not form tumors but can differentiate into various types of cells, as has been shown in actual treatments in people.

"When you look at just the published scientific evidence," Dr. David Prentice told an audience at the 2009 NRLC National Convention, "there are at least 73 different diseases and injuries where adult stem cells have already helped human patients, saved lives, and improved health. Thousands of patients."

Part One