High-Tech Treatments for the Heart
Researchers Grow New Arteries, Heart Cells
As soon as the cells grew into a thin sheet, they were wrapped around a thin, stainless steel tube about the size of a blood vessel. The tissue continued to grow or mature until it took on the shape of the tube. At that point the tube was carefully removed and the vessel was ready for surgical implant.
McAllister says the whole process from skin biopsy to finished blood vessel takes about three months, but once the vessel is grown it remains healthy and viable for surgical bypass for up to six months.
In his experiment, the dogs were monitored for up to 14 days after surgery. During that time the vessels functioned as well as native blood vessels with no clots or blockages, says McAllister. The vessels were then surgically removed and examined. Again, McAllister said, the vessels were virtually indistinguishable form healthy, native blood vessels.
Valentin Fuster, MD, PhD, director of the cardiovascular institute at Mount Sinai Medical Center, New York, says the new vessel-growing technology is coming along at a time when it is sorely needed because the new emphasis on early detection of heart disease means that "many more patients are having many more procedures." This means that a rapidly growing number of heart disease patients have already run the gamut of available treatments.
Moreover, Fuster, who did not participate in McAllister's study, says that patients with diabetes may be particularly good candidates for this technology because they have widespread disease that affects their hearts as well as circulation in the legs. Another group that is likely to benefit is dialysis patients because after repeated dialysis treatments veins collapse and have to be replaced with vein grafts.
McAllister says that dialysis patients will actually be the first patients recruited for human studies because "this is not a life-threatening procedure in these patients." If those studies are successful, patients needing bypass procedures for blocked arteries in their legs will be studied and finally the engineered vessels will be tried in heart bypass surgery.
While McAllister is engineering new blood vessels, other researchers are using muscle and bone marrow cells to rejuvenate damaged heart tissue.