Skeletal muscle depletion, referred to as sarcopenia, predicts morbidity and mortality in patients undergoing digestive surgery. However, the impact on liver transplantation is unclear. The present study investigated the impact of sarcopenia on patients undergoing living donor liver transplantation (LDLT). Sarcopenia was assessed by a body composition analyzer in 124 adult patients undergoing LDLT between February 2008 and April 2012. The correlation of sarcopenia with other patient factors and the impact of sarcopenia on survival after LDLT were analyzed. The median ratio of preoperative skeletal muscle mass was 92% (range, 67–130%) of the standard mass. Preoperative skeletal muscle mass was significantly correlated with the branched‐chain amino acids to tyrosine ratio (r = −0.254, p = 0.005) and body cell mass (r = 0.636, p < 0.001). The overall survival rate in patients with low skeletal muscle mass was significantly lower than in patients with normal/high skeletal muscle mass (p < 0.001). Perioperative nutritional therapy significantly increased overall survival in patients with low skeletal muscle mass (p = 0.009). Multivariate analysis showed that low skeletal muscle mass was an independent risk factor for death after transplantation. In conclusion, sarcopenia was closely involved with posttransplant mortality in patients undergoing LDLT. Perioperative nutritional therapy significantly improved overall survival in patients with sarcopenia.

The liver is a unique organ with an abundant regenerative capacity. Therefore, partial hepatectomy (PHx) or partial liver transplantation (PLTx) can be safely performed. Liver regeneration involves a complex network of numerous hepatotropic factors, cytokines, pathways, and transcriptional factors. Compared with liver regeneration after a viral- or drug-induced liver injury, that of post-PHx or -PLTx has several distinct features, such as hemodynamic changes in portal venous flow or pressure, tissue ischemia/hypoxia, and hemostasis/platelet activation. Although some of these changes also occur during liver regeneration after a viral- or drug-induced liver injury, they are more abrupt and drastic following PHx or PLTx, and can thus be the main trigger and driving force of liver regeneration. In this review, we first provide an overview of the molecular biology of liver regeneration post-PHx and -PLTx. Subsequently, we summarize some clinical conditions that negatively, or sometimes positively, interfere with liver regeneration after PHx or PLTx, such as marginal livers including aged or fatty liver and the influence of immunosuppression.

Objective: To evaluate preoperative body composition, including skeletal muscle and visceral adipose tissue, and to clarify the impact on outcomes after hepatectomy for hepatocellular carcinoma (HCC). Background: Recent studies have indicated that sarcopenia is associated with morbidity and mortality in various pathologies, including cancer, and that obesity or visceral adiposity represents a significant risk factor for several cancers. However, the impact of sarcopenic obesity on outcomes after hepatectomy for HCC has not been fully investigated. Methods: We retrospectively analyzed 465 patients who underwent primary hepatectomy for HCC between April 2005 and March 2015. Skeletal muscle mass and visceral adipose tissue were evaluated by preoperative computed tomography to define sarcopenia and obesity. Patients were classified into 1 of 4 body composition groups according to the presence or absence of sarcopenia and obesity. Results: Body composition was classified as nonsarcopenic nonobesity in 184 patients (39%), nonsarcopenic obesity in 219 (47%), sarcopenic nonobesity in 31 (7%), and sarcopenic obesity in 31 (7%). Compared with patients with nonsarcopenic nonobesity, patients with sarcopenic obesity displayed worse median survival (84.7 vs. 39.1 mo, P = 0.002) and worse median recurrence-free survival (21.4 vs. 8.4 mo, P = 0.003). Multivariate analysis identified sarcopenic obesity as a significant risk factor for death (hazard ratio [HR] = 2.504, P = 0.005) and HCC recurrence (HR = 2.031, P = 0.006) after hepatectomy for HCC. Conclusion: Preoperative sarcopenic obesity was an independent risk factor for death and HCC recurrence after hepatectomy for HCC.

Background: Skeletal muscle depletion has been shown to be an independent risk factor for poor survival in various diseases. However, in surgery, the significance of other body components including visceral and subcutaneous adipose tissue remains unclear. Methods: This retrospective study included 250 adult patients undergoing living donor liver transplantation (LDLT) between January 2008 and April 2015. Using preoperative plain computed tomography imaging at the third lumbar vertebra level, skeletal muscle mass, muscle quality, and visceral adiposity were evaluated by the skeletal muscle mass index (SMI), intramuscular adipose tissue content (IMAC), and visceral to subcutaneous adipose tissue area ratio (VSR), respectively. The cutoff values of these parameters were determined for men and women separately using the data of 657 healthy donors for LDLT between 2005 and 2016. Impact of these parameters on outcomes after LDLT was analyzed. Results: VSR was significantly correlated with patient age (P = 0.041), neutrophil-lymphocyte ratio (P < 0.001), body mass index (P < 0.001), and SMI (P = 0.001). The overall survival probability was significantly lower in patients with low SMI (P < 0.001), high IMAC (P < 0.001), and high VSR (P < 0.001) than in each respective normal group. On multivariate analysis, low SMI (hazard ratio [HR], 2.367, P = 0.002), high IMAC (HR, 2.096, P = 0.004), and high VSR (HR, 2.213, P = 0.003) were identified as independent risk factors for death after LDLT. Conclusions: Preoperative visceral adiposity, as well as low muscularity, was closely involved with posttransplant mortality.