Lipid abnormalities of xanthomatous nerves

The lipid composition of nerves, with and without xanthomatous alteration, and other tissues, was investigated post-mortem in a 36-year-old man with cholestatic hepatitis of unknown cause and insulin-dependent diabetes mellitus (IDDM). Cholesteryl esters were found to be markedly increased in both endoneurium and epi- and perineurium of hepatic nerves (showing xanthomatous change), but not in sciatic nerve (without this change). Cholesteryl ester concentrations were also increased, but to a lesser degree, in kidney tissue. The fatty acid composition of stored cholesteryl esters in hepatic nerve endoneurium revealed that oleic acid was the most favoured substrate for esterification. A widespread depletion of triacylglycerol was also demonstrated in hepatic and sciatic nerves and liver and skin tissues obtained from this patient. This abnormality did not appear to be due to an alcoholic or biliary cirrhosis, or to inanition. Whether the depletion of triacylglycerol is drug-related or represents an endogenous metabolic error remains unclear.