INNERVATION OF THE SKIN OF THE FOREARM IN DIABETIC-PATIENTS - RELATION TO NERVE FUNCTION

Complications of diabetes include sensory and autonomic neuropathy. Th e aim of the present paper was to study the degree of sensory and auto nomic neuropathy and correlate these findings with the distribution an d density of neuropeptidergic nerve fibers in the skin of the forearm of diabetic patients and healthy controls. We investigated 30 diabetic s (24 type 1 and 6 type 2) and compared them with 13 healthy controls. There were no differences between the groups with respect to density and distribution of nerve fibers displaying immunoreactivity to the pa n-neuronal marker PGP 9.5 and sensory and parasympathetic neuropeptide s (substance P, calcitonin gene-related peptide and vasoactive intesti nal peptide). By contrast, nerve fibers containing neuropeptide Y, a m arker of sympathetic neurons, were reduced in number in the diabetic p atients. C-fiber function (measured as the axon-reflex-evoked flare re sponse) became impaired with increasing age in all subjects. The diabe tic patients, however, showed a reduced flare compared to age-matched healthy controls. The reduction was particularly prominent in the youn ger patients (20-50 years). There was a greater reduction of the flare in neuropathic patients than in non-neuropathic patients, but there w as no correlation between the degree of functional impairment and the duration of the disease.