Boston, Mass. -- Hemangiomas -- strawberry-like birthmarks that commonly develop in early infancy are generally harmless, but up to 10 percent cause tissue distortion or destruction and sometimes obstruction of vision or breathing. Since the 1960s, problematic hemangiomas have been treated with corticosteroids such as dexamethasone or prednisone. But steroids have considerable side effects, don't always work, and their mechanism of action in hemangioma has remained a mystery. Researchers at Children's Hospital Boston recently discovered that infantile hemangiomas originate from stem cells, and have used these stem cells to better understand this tumor in the laboratory. In the March 18 issue of the New England Journal of Medicine, they show that steroids target hemangioma stem cells specifically, reveal their mechanism of their action and suggest other possible ways to halt and shrink hemangiomas.
Hemangiomas, affecting 4 to 10 percent of infants, are noncancerous tumors consisting of a tangled mass of blood vessels. Previously, it was assumed that steroids act on endothelial cells, which make up about 30 percent of cells in the tumor. The new research, led by dermatologist Shoshana Greenberger, MD, PhD, working in the lab of Joyce Bischoff, PhD, in Children's Vascular Biology Program, shows that steroids interfere with a much rarer and more primitive cell type hemangioma stem cells.
Greenberger and Bischoff further showed that steroids work by inhibiting hemangioma stem cells' ability to stimulate blood vessel growth, and that they do so by shutting down production of a specific factor called vascular endothelial growth factor (VEGF-A). VEGF is well known as a stimulator of angiogenesis (blood vessel growth) in cancer and age-related macular degeneration.
"We now have more therapies targeting VEGF, so our findings open the way to finding a more specific and safer therapy for hemangioma," says Greenberger.
|Contact: Keri Stedman|
Children's Hospital Boston