Contribution of elevated protein turnover and anorexia to cachexia in patients with hepatocellular carcinoma

Abstract

Severe cachexia of extremely rapid onset typifies the young Black African patient with hepatocellular carcinoma (HCC). In order to assess whether this is a consequence of tumor-associated increases in protein metabolism or simply due to inadequate dietary intake, the following study was undertaken. The technique of constant i.v. infusion of 14C-labeled leucine was used to measure whole body protein flux, breakdown, synthesis, and oxidation rates in 8 adults with HCC, 4 patients with massive hepatomegaly due to metastatic adenocarcinoma from bowel, 6 patients with chronic liver disease, and 10 controls. Endogenous protein breakdown and oxidation were similar between patients with chronic liver disease (breakdown, 4.4 +/- 1.2 g/kg/day; oxidation, 0.8 +/- 0.4 g/kg/day) and controls but were significantly (P less than 0.002) higher in patients with liver tumors, the highest rates being observed in those with HCC (breakdown, 8.5 +/- 4.3 g/kg/day; oxidation, 1.4 +/- 0.5 g/kg/day). Protein turnover was generally higher in the HCC group, with increased rates of reincorporation of amino acids into protein synthesis (P less than 0.05). In one HCC patient a synchronized diagnostic liver biopsy demonstrated high fractional synthesis of rates of HCC proteins of 86%/day. In addition, the incorporation rates of labeled amino acid into fibrinogen, immunoglobulin G, and transferrin were also highest (P less than 0.03) in HCC patients. In order to assess the relative importance of diet in weight loss, dietary intake levels were assessed from hospital records of HCC patients and by dietary recall during the week prior to study. Intakes ranged from 30 to 70% of calculated requirement levels. In conclusion, our results suggest that the rapid wasting seen in patients with HCC is due to an imbalance between the metabolic demands, which can be elevated in some patients, and inadequate dietary replenishment.