Vascular anomalies include both vascular malformations and vascular tumors (most commonly hemangiomas). Hemangiomas, found in about 10 percent of infants, occur when the cells lining blood vessels multiply abnormally. Hemangiomas grow rapidly in the first year of life, then usually shrink and disappear. But some grow large, causing obstruction, ulceration, and other problems. Vascular malformations occur during fetal development, usually growing in proportion to the child, but sometimes progress during adolescence or pregnancy, or after surgery or trauma, in rare instances becoming fatal.
Marsha Moses, Ph.D., of Children’s Vascular Biology Program, senior investigator on the study, had been studying the matrix metalloproteinases (MMPs), a family of enzymes required for angiogenesis. Angiogenesis is critical to cancer growth, and Moses showed that MMP inhibitors can inhibit angiogenesis. Her lab also demonstrated elevated MMP levels in the urine of cancer patients. Moses collaborated with Jennifer Marler, M.D., a fellow in the laboratory of Judah Folkman, M.D., at Children’s Hospital Boston and a clinical fellow in Children’s Vascular Anomalies Center.
Moses, Marler and colleagues tested urine in vascular anomaly patients and in healthy controls. MMPs were elevated in the urine of 53 percent of patients with vascular tumors and 41 percent of those with vascular malformations, but in only 22 percent of controls. Vascular anomalies were also associated with elevated urine levels of basic fibroblast growth factor (bFGF), another angiogenesis promoter.