Differential fuel utilization in liver transplant recipients and its relationship with non‐alcoholic fatty liver disease

• Published in: Liver international Vol. 42; no. 6; pp. 1401 - 1409
• Main Authors: Siddiqui, Mohammad S., Patel, Samarth, Forsgren, Mikael, Bui, Anh T., Shen, Steve, Syed, Taseen, Boyett, Sherry, Chen, Shanshan, Sanyal, Arun J., Wolver, Susan, Kirkman, Danielle, Celi, Francesco S., Bhati, Chandra S.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-06-2022
• Subjects: Adipose tissue; Biofuels; Body mass; Body mass index; Body size; Calorimetry; Carbohydrates; Cirrhosis; Complications; Diabetes mellitus; energy expenditure; Fasting; Fatty acids; Fatty liver; Flexibility; Humans; Liver; Liver cirrhosis; Liver Cirrhosis - complications; Liver diseases; Liver transplantation; Liver Transplantation - adverse effects; Magnetic resonance imaging; metabolic flexibility; Metabolism; Muscles; Non-alcoholic Fatty Liver Disease - epidemiology; non‐alcoholic steatohepatitis; Obesity; Obesity - complications; Oxidation; Quotients; Respiratory quotient; Subgroups; Transplantation; Transplants & implants; Utilization; carbohydrates; metabolic flexibility; fatty acids; energy expenditure; liver transplantation; non-alcoholic steatohepatitis
• ISSN: 1478-3223; 1478-3231; 1478-3231
• DOI: 10.1111/liv.15178

Metabolic flexibility is the ability to match biofuel availability to utilization. Reduced metabolic flexibility, or lower fatty acid (FA) oxidation in the fasted state, is associated with obesity. The present study evaluated metabolic flexibility after liver transplantation (LT).
Methods
Patients receiving LT for non‐alcoholic steatohepatitis (NASH) (n = 35) and non‐NASH (n = 10) were enrolled. NASH was chosen as these patients are at the highest risk of metabolic complications. Metabolic flexibility was measured using whole‐body calorimetry and expressed as respiratory quotient (RQ), which ranges from 0.7 (pure FA oxidation) to 1.0 is (carbohydrate oxidation).
Results
The two cohorts were similar except for a higher prevalence of obesity and diabetes in the NASH cohort. Post‐prandially, RQ increased in both cohorts (i.e. greater carbohydrate utilization) but peak RQ and time at peak RQ was higher in the NASH cohort. Fasting RQ in NASH was significantly higher (0.845 vs. 0.772, p < .001), indicative of impaired FA utilization. In subgroup analysis of the NASH cohort, body mass index but not liver fat content (MRI‐PDFF) was an independent predictor of fasting RQ. In NASH, fasting RQ inversely correlated with fat‐free muscle volume and directly with visceral adipose tissue.
Conclusion
Reduced metabolic flexibility in patients transplanted for NASH cirrhosis may precede the development of non‐alcoholic fatty liver disease after LT.