Scientists are hoping to treat leprosy by taking advantage of one of its most distinctive characteristics--the richly vascularized skin lesions that typify this disease.
Led by Jack Arbiser, MD, PhD, professor of dermatology at Emory University School of Medicine, the scientists found that different stages of leprosy, ranging from early solitary inflammatory bumps, known as tuberculoid, to more advanced bacteria-laden nodules or tumors, known as lepromatous, vary widely in the number of blood vessels they contain.
"Our findings demonstrate a significant increase in angiogenesis--blood vessel formation--toward the lepromatous spectrum of lesions, thus raising the possibility that angiogenesis inhibitors, drugs that prevent the growth of new blood vessels, may be useful in treating leprosy," says Dr. Arbiser.
Results of the study are published online in the Archives of Dermatology.
"The infections from leprosy take years to get rid of. They set up shop in cells called macrophages and form a symbiosis with the patient, like tumors, which sometimes can be treated with angiogenesis inhibitors. The idea of treating tumors with angiogenesis inhibitors made me wonder if leprosy could be treated in the same way," says Dr. Arbiser.
Although treatment for leprosy is available, the disease requires long courses of multiple antibiotics, which can decrease compliance and increase resistance to antibiotics used to treat the disease.
"If we use an angiogenesis inhibitor, such as interleukin 12 or thalidomide, we may be able to shorten the length of therapy," says Dr. Arbiser.
Leprosy, also known as Hansen's disease, is a chronic infection caused by Mycobacterium leprae, which is endemic to the tropics. The disease causes ulcers, eye disabilities, neuropathy, deformities, and in many instances, social isolation and disability. In 2002, the number of new cases detected worldwide was 763,917, according to the Centers for Disease Control and Prevention.
The next step would be a robust clinical trial, says Dr. Arbiser. And if angiogenesis inhibitors prove successful in treating leprosy it's possible they may prove effective in treating other stubborn chronic infections such as tuberculosis, he says. Both diseases are caused by a bacterium in the same family.
In addition to Dr. Arbiser, the research was conducted by Emory dermatologists Sulochana Bhandarkar, MD, and Jamie MacKelfresh, MD; Emory pathologist Cynthia Cohen, MD; Delphine Lee, MD, PhD, and Robert Modlin, MD, University of California at Los Angeles; Maria Kuruvila, MD, Kasturba Medical College, Mangalore, India; and Thomas Rea, MD, University of Southern California.
This study was supported by the National Institutes of Health.