CLEARANCE RATE OF PLASMA BRANCHED-CHAIN AMINO-ACIDS CORRELATES SIGNIFICANTLY WITH BLOOD AMMONIA LEVEL IN PATIENTS WITH LIVER-CIRRHOSIS

Reduced plasma free branched-chain amino acid (BCAA; valine, isoleucine and leucine) levels appear often in patients with liver cirrhosis and relate closely to the pathogenesis of hepatic encephalopathy and protein malnutrition in cirrhotics. To elucidate possible mechanism(s) of the BCCA decrease, plasma amino acid clearance rates were estimated by analyzing disappearance curves of amino acids which were infused at a rate of 0.1 g/kg per 5 min in ten patients and eight controls. The clearance rate of total amino acids (TAA) was significantly lower while that of BCAA was significantly higher in cirrhotics than in controls. The relative clearance rate of BCAA (% TAA clearance) correlated significantly with the blood ammonia level. Since BCAA is required for the detoxication of ammonia in skeletal muscles, enhanced clearance of plasma BCAA may indicate the increased muscular uptake of BCAA. In conclusion, plasma BCAA reduction in cirrhotics is due, at least in part, to the enhanced plasma BCAA clearance, and hyperammonemia seems to be responsible for this enhancement. Supplementation with BCAA in these patients is reasonable to rescue this pathophysiological state of relative BCAA deficiency.