Every cell in your body—whether bone or cartilage or even fat—can be traced to its origin in stem cells. Given the right circumstances, these impressionable cells can become anything they come near. Scientists have discovered much about these cells' origins—that they are found in fetal umbilical cords and primordial fat cells, for example.
Now, if researchers can figure out how to control them, stem cells hold limitless possibilities. Among these are the ability to re-grow brain cells in Parkinson's patients, pancreas cells in diabetics, and heart cells for sufferers of heart conditions, according to Reuters Health.
Researchers are now looking into harvesting and using the cells to repair a torn meniscus in patients' knees. The meniscus, a disc-like cushion within the knee, absorbs most of the shock the joint experiences. An injury to the area, most often brought on by repeated squatting or lunging, severely increases wear and tear on other parts of the leg.
Dr. Frank Noyes, president of Cincinnati Sportsmedicine and Orthopedic Center, one of an elite few groups that is studying the possibility of stem cells fixing bum knees. "The work that we've done so far with stem cells is for tendon and ligament healing," Noyes said in a recent interview with Knee1. The question the researchers face, Noyes says, is whether a cell will become a chondrocyte, or cartilage cell, or fibrochondrocyte, a type of cell somewhere between cartilage and connective tissue, specifically found in the meniscus. "We don’t yet have the answer to that question," Noyes says.
Cincinnati Sportsmedicine and Orthopedic Center has worked with the University of Cincinnati's engineering department for about five years to seek an answer to the quandary, Noyes says. Researchers not only have to figure out how a cell becomes fibrocartilage or regular cartilage, but also determine what conditions, or growth factors, aid in its developement. Next, they have to understand how to grow the specific type of tissue outside of the body—which has been done experimentally with a number of tissues of late, but not with the meniscus.
The next challenge after all the clinical research is completed is how to get these cells to bridge the gap in the meniscal tear. Researchers have toyed with the possibility of a biodegradable web-like matrix coated with stem cells implanted into joint, but have yet to develop a working prototype tested in humans. "We believe that, in the future, we'll be able to have a collagen meniscus with a patient's cells that are transposed into a meniscus, and the patient will be able to regenerate their own meniscus," Noyes said. "It may be as much as 10 years in the future, though."
Current meniscal repair involves either simply stitching the meniscus back together, removing it all, or transplanting one from a cadaver. Cincinnati Sportsmed has performed more than 160 allograft transplants. "The meniscal transplant offers a suitable alternative for patients in their 20s and 30s who have lost the meniscus," Noyes said. "The problem is that we do not know how long a meniscus transplant will function. Because it is so unpredictable, it has made us push the curve more to repair anything and not be in the meniscus transplant business."
In addition, many insurance companies do not cover the cadaver procedure, known as an allograft, declaring it experimental, Noyes says. Although the stem cell is extremely experimental, it may have a greater acceptance rate by insurance companies since the cells come from the patient's own body. Like Noyes says, however, such advances in meniscal repair may not emerge for as long as 10 years. However, a great push for research on stem cells in many areas—from cancer to heart disease to diabetes—may speed up the timetable.
Resources:
Norton, Amy. "Stem Cells From Body Fat—Limitless Supply." Reuters Health. 18 Oct. 2000. Online at:
http://dailynews.yahoo.com/h/nm/20001018/hl/stemcells_2.html.
Fox, Maggie. "Scientists Find Way to Program Key Cells." Reuters Health. 9 Oct. 2000. Online at:
http://dailynews.yahoo.com/h/nm/20001009/sc/cells_dc_1.html.
