Resting and Exercise Energy Metabolism after Liver Transplantation for Nonalcoholic Steatohepatitis

Background. Nonalcoholic steatohepatitis (NASH) is a leading indication for liver transplantation (LT). We hypothesized that weight gain after LT may be exacerbated by reduced metabolic rates due to the LT procedure, particularly during exercise. We aimed to compare resting and exercise energy expenditure between patients transplanted for NASH and nontransplant nonalcoholic fatty liver disease (NAFLD) subjects. Methods. NASH LT recipients (>1-year post, n = 14) and NAFLD controls (n = 13) underwent analysis of body composition, resting energy expenditure (REE), and exercise energy expenditure (VO_2max), the latter using a ramped-Bruce protocol assessed by expired gas analysis and peak heart rate. Results. Participants were mean 61.5 ± 7.9 years, 48.1% men, and 66.7% white. Baseline comorbidities were similar between groups. Among men, mean REE adjusted for total (17.7 vs 18.8, P = 0.87) and lean body mass (23.5 vs 26.9, P = 0.26), as well as VO₂ (20.1 vs 23.9, P = 0.29), was lower in NASH LT recipients compared with NAFLD controls, respectively, although not statistically significant. However, female NASH LT recipients had significantly lower mean REE than NAFLD controls when adjusted for total (14.2 vs 18.9, P = 0.01) and lean body mass (19.3 vs 26.5, P = 0.002), as well as significantly lower VO_2max (14.4 vs 20.6, P = 0.017). Conclusions. NASH LT recipients, particularly women, have lower REE and exercise energy expenditure compared with nontransplant NAFLD patients. More aggressive diet and exercise programs for post-LT NASH recipients to account for reduced resting and exercise metabolic rates may attenuate weight gain in this vulnerable population.