In addition to numbness and tingling in the extremities, diabetes-induced nerve damage can also lead to problems with control of high blood pressure and cause incontinence, impotence, chronic diarrhea and constipation. This kind of autonomic neuropathy occurs when the branching extensions of nerve cells swell and block normal communication between the cells.
In tests that were published in the November 1999 issue of the American Journal of Pathology. Robert E. Schmidt, MD, PhD, and his colleagues at the Washington School of Medicine in St. Louis say that an insulin-like growth factor (IGF-I) may help reverse this process. IGF-I occurs naturally in humans and animals, and is known to act on many tissues and organs, including the brain and peripheral nerves. IGF-I resembles insulin structurally, but acts on a different receptor.
Schmidt was able to almost completely reverse nerve damage in 8 long-term diabetic rats which were given daily injections of IGF-I over 8 weeks. Despite the promising results, Schmidt admits that it is still not clear how IGF-I works. Earlier research had shown that humans and rats with diabetes have reduced levels of IGF-I in their blood, and that the injections of IGF-I may help restore nerves which have been damaged by diabetes.
Schmidt warns that IGF-I was effective in reversing nerve damage, but not in reducing elevated blood glucose levels.
“Although precise control of blood sugar levels would eliminate the development of nerve damage in diabetics, this is often hard to achieve,” says Schmidt. “The hope is that these findings might help prevent diabetic nerve complications even in people who can’t control their blood glucose well.”