[Carnitine--biochemistry and clinical aspects]

Abstract

Carnitine was discovered in 1905. The human organism is able to synthetize carnitine from lysine and methionine. However the most important source of carnitine in human nutrition is meat. Carnitine plays a central role in the oxidation of long chain fatty acids, mediating their transport across the inner mitochondrial membrane. By means of the intramitochondrial reaction of acetyl-CoA with carnitine it favours an improved availability of CoA. This mechanism seems to be of major importance when pathological short chain fatty acids are accumulated within the mitochondrial matrix. Carnitine deficiency can be inborn or acquired. Thereby myopathy is always a prominent clinical symptom. Secondary carnitine deficiency occurs most frequently in uremic patients under intermittent hemodialysis. There is a positive inotropic effect of carnitine on the ischemic heart muscle. As a consequence of this effect, carnitine is on the way to become a substance with broadest clinical indications. If young infants are alimented parenterally with fat emulsions, carnitine should be substituted. This also happens to be the case in adult patients when total parenteral nutrition lasts longer than 20 days.