A COMPARISON OF PERINEURIAL AND VASCULAR BASAL LAMINAL CHANGES IN DIABETIC NEUROPATHY

Measurements were made of the thickness of the basal lamina of perineu rial cells in the sural nerve in a series of patients with diabetic ne uropathy and compared with a group of patients with type I hereditary motor and sensory neuropathy (HMSN) and with organ donor control cases . The thickness was significantly greater in the diabetic patients as compared both with the HMSN cases and the organ donor controls. This w as most obvious for the intermediate layers of the perineurium. Perine urial basal laminal thickness was only slightly greater in the HMSN ca ses than in the organ donor controls and the diffference was not stati stically significant. The thickening of the perineurial cell basal lam inae was compared with the thickening of the basal laminal zone around the endoneurial microvessels. No significant correlation was found ei ther for the diabetic neuropathy or HMSN cases or for the organ donor controls. As had been observed previously, the basal laminal zone arou nd the endoneurial capillaries was of increased thickness both in the diabetic neuropathy and the HMSN cases and, although it was greater fo r the diabetic neuropathy patients, the difference was not statistical ly significant. Taken together, these findings indicate that the thick ening of the basal lamina of the perineurial cells is a more character istic feature of diabetic neuropathy than is thickening of the basal l aminal zone around the endoneurial capillaries. The results suggest th at the causative mechanisms are likely to differ, a conclusion support ed by the morphological appearances: the basal laminal thickening arou nd the perineurial cells is uniform, whereas that around the capillari es consists of basal laminal reduplication. Atrophy and necrosis of pe rineurial cells were observed in patients with diabetic neuropathy but rarely in the cases with HMSN and not in the organ donor cases. This may be similar to the degeneration of endoneurial fibroblasts that has been described as a non-specific finding in neuropathies.