Light and electron microscopic changes in sural nerves in Ethiopian diabetics.

The light and electron microscopic morphological changes in sural nerve biopsies from 32 Ethiopian diabetics and 4 malnourished non-diabetic subjects were studied in order to determine the role of malnutrition in the development of diabetic neuropathy. The most prominent finding in diabetics with clinical neuropathy was reduction in the density of myelinated axons of all diameters especially the large ones. Affected nerves showed abundant intraneural collagen, and evidence of nerve regeneration in some cases. Demyelination, though present, was less marked. Changes in the vasa nervorum were seen in only one case. The morphological changes correlated with the duration and severity of the diabetes and with nerve conduction velocity. No changes were seen in malnourished non-diabetics and diabetics without clinical neuropathy, thus suggesting that malnutrition by itself does not contribute significantly to the development of diabetic neuropathy. Axonal degeneration appears to be the predominant feature in diabetic neuropathy.