Vessels of Death or Life; Tackling Major Killers: Cancer; Exclusive Online Issues; by Rakesh K. Jain and Peter F. Carmeliet; 7 Page(s)
They snake through our bodies, literally conveying our life's blood, their courses visible through our skin only as faint bluish tracks or ropy cords. We hardly give them a thought until we cut ourselves or visit a clinic to donate blood. But blood vessels play surprisingly central roles in many serious chronic disorders. New growth of the body's smallest vessels, for instance, enables cancers to enlarge and spread and contributes to the blindness that can accompany diabetes. Conversely, lack of small vessel, or capillary, production can contribute to other ills, such as tissue death in cardiac muscle after a heart attack. Accordingly, we and other scientists are working to understand the mechanisms that underlie abnormal vessel growth. This effort will help us develop and optimize drugs that block vessel growth-or improve vessel function.
The study of small vessel growth-a phenomenon referred to generally as angiogenesis-has such potential for providing new therapies that it has been the subject of countless news stories and has received enthusiastic interest from the pharmaceutical and biotechnology industries. Indeed, dozens of companies are now pursuing angiogenesis-related therapies, and approximately 20 compounds that either induce or block vessel formation are being tested in humans. Although such drugs can potentially treat a broad range of disorders [see boxes on opposite page and on page 43], many of the compounds now under investigation inhibit angiogenesis and target cancer. We will therefore focus the bulk of our discussion on those agents. Intriguingly, animal tests show that inhibitors of vessel growth can boost the effectiveness of traditional cancer treatments (chemotherapy and radiation). Preliminary studies also hint that the agents might one day be delivered as a preventive measure to block malignancies from arising in the first place in people at risk for cancer.