In patients with diabetes, nerve fiber damage that causes diabetic neuropathy is irreversible. Now, in a new study sponsored by the National Institutes of Health, researchers have found that with weight loss and exercise in patients with impaired glucose tolerance neuropathy — so-called prediabetes — the affected nerve fibers can be reinervated, causing a reduction in the patients’ pain.
Dr. A Gordon Smith stated that, "It’s been clear that aggressive control of blood glucose levels slows the risk of neuropathy, but no treatment has ever before resulted in improved neuropathy. "We certainly never thought that reinvervation would be possible at the prediabetic state."
Dr. Smith and his associates, from the University of Utah in Salt Lake City, enrolled 32 subjects with impaired glucose tolerance neuropathy, and performed skin biopsies at the distal leg and in the proximal thigh to measure intraepidermal nerve fiber density.
"Then we set a weight loss goal of 7%, along with 150 minutes of moderate exercise per week," the researcher said. "Every 3 months the patients also had individual counseling with a nutritionist."
Baseline intraepidermal nerve fiber density was 0.9 fibers/mm in the distal leg and 4.8 fibers/mm in the thigh. After 1 year of dieting and regular exercise, the investigators measured a 0.3 fiber/mm improvement in the distal leg and 1.4/mm in the thigh (p < 0.004).
Moreover, the change in fiber density in the thigh was inversely correlated with neuropathic pain (p < 0.05). However, patients with the most reduced intraepidermal nerve fiber density were unlikely to experience relief of their symptoms, Dr. Smith said.
"If you see a patient with symptoms of neuropathy – numbness, tingling pain, or absence of sensation — you should conduct an oral glucose tolerance test and confirm nerve fiber loss by such measures as nerve conduction testing, quantitative sensory testing, and quantitative sudomotor axon reflex testing," Dr. Smith advised
"If they turn out to be glucose intolerant with peripheral neuropathy, you should treat them as aggressively as possible with diet and exercise," Dr. Smith concluded. " Simply treating them with antihyperglycemic drugs appears to not allow damaged nerve fibers to recover," he added.
Presented at the American Academy of Neurology 58th Annual Meeting in San Diego.
DID YOU KNOW:
Diabetes Soars Among Youths: Twice as many youngsters and teens are taking medication typically used to treat or prevent Type 2 diabetes than four years ago, according to a study by Express Scripts Inc., one of the nation’s largest pharmacy benefit managers. Researchers reviewed the prescription records of at least 3.7 million Express Scripts members, all between 5 and 19. They found the number of prescriptions for anti-diabetic medication rose to 0.6 per 1,000 children from 0.3. The use of these medications was most prevalent in older teens. By 2005, slightly more than 1 out of every 1,000 15- to 19-year-olds had been prescribed medication to treat or prevent Type 2 diabetes, in which people respond abnormally to the insulin their bodies produce.