At the same time, loss of the endothelial cells incites production of other factors that promote smooth muscle cell growth. Dr. Karnovsky had earlier showed that endothelial cells produce a native form of the compound heparin to counteract growth of smooth muscle cells. They also showed how heparin could take the place of the native compound to control diseases of the blood vessel wall characterized by excessive smooth muscle cell growth. In coordination with Dr. Edelman, he studied the optimum route of administration. Heparin cannot be taken by mouth without loss of its biological activity, but if injected, it can lead to serious systemic side effects.
Current studies focus on defining the ideal duration of drug administration.
Researchers hope that a brief period of microspherical heparin release after surgery will permanently inhibit excessive smooth muscle cell growth. In a sense, it's a secondary general science. For instance, Dr. Nathan used her background in polymer chemistry and her more recently acquired knowledge of cell biology to determine the optimum physical and chemical properties for the drug delivery system. Moreover, the devices degraded in the body without inducing an inflammatory response or injury of their own. Edelman and Nathan hope that further work refining the technology of localized drug delivery directly to blood vessels might provide added insight into the biology of vascular disease and potential alternative therapies for these illnesses.