Carnitine metabolites in infants with cystic fibrosis: a prospective study.

Abstract

Acylcarnitine is low in cord blood in patients with cystic fibrosis, suggesting that fatty acid metabolism is disturbed in utero. Carnitine metabolites (total, free, short- and long-chain acylcarnitine) were measured prospectively in 23 newly diagnosed infants with cystic fibrosis treated with a carnitine-containing, predigested formula for 6-12 months. Total (p < 0.002), free (p < 0.004), and long-chain (p < 0.001) plasma concentrations of carnitines were significantly less than controls (n = 48) at diagnosis. Total and free concentrations were corrected with nutritional management, whereas short- and long-chain acylcarnitines remained unchanged. By three years of age all plasma concentrations of carnitine metabolites were significantly less than controls despite a carnitine-containing diet. Urinary carnitine metabolites were increased at diagnosis and follow-up. The physiological significance of these observations in cystic fibrosis is unknown, but could be compatible with disturbed regulatory control with resultant increased utilization.