Body composition and the skeletal muscle compartment in liver transplantation: Turning challenges into opportunities

Shining a spotlight on sarcopenia and myosteatosis in liver disease and liver transplantation: Potentially modifiable risk factors with major clinical impact

Muscle-wasting and disease-related malnutrition are highly prevalent in patients with chronic liver diseases (CLD) as well as in liver transplant (LT) candidates. Alterations of body composition (BC) such as sarcopenia, myosteatosis and sarcopenic obesity and associated clinical frailty were tied to inferior clinical outcomes including hospital admissions, length of stay, complications, mortality and healthcare costs in various patient cohorts and clinical scenarios. In contrast to other inherent detrimental individual characteristics often observed in these complex patients, such as comorbidities or genetic risk, alterations of the skeletal muscle and malnutrition are considered as potentially modifiable risk factors with a major clinical impact. Even so, there is only limited high-level evidence to show how these pathologies should be addressed in the clinical setting. This review discusses the current state-of-the-art on the role of BC assessment in clinical outcomes in the setting of CLD and LT focusing mainly on sarcopenia and myosteatosis. We focus on the disease-related pathophysiology of BC alterations. Based on these, we address potential therapeutic interventions including nutritional regimens, physical activity, hormone and targeted therapies. In addition to summarizing existing knowledge, this review highlights novel trends, and future perspectives and identifies persisting challenges in addressing BC pathologies in a holistic way, aiming to improve outcomes and quality of life of patients with CLD awaiting or undergoing LT.

Association of myosteatosis with short-term outcomes in patients with acute-on-chronic liver failure

Sarcopenia (low muscle mass, i.e., quantity) is associated with poor clinical outcomes in patients with acute-on-chronic liver failure (ACLF). In this study, we aimed to illustrate the clinical prognostic value of myosteatosis (muscle fat infiltration) for short-term mortality in patients with ACLF. We retrospectively enrolled consecutive patients with ACLF between January 2019 and January 2022. Computed tomography-based body composition analysis was performed at the third lumbar vertebral level to determine skeletal muscle radiation attenuation. Fine and Gray's competing risk regression model, with liver transplantation as a competing risk, was used to assess the factors associated with 90-day mortality. A total of 431 patients with ACLF were included. Myosteatosis and sarcopenia were observed in 261 (60.6%) and 87 (20.2%) patients, respectively. Competitive risk regression showed that age (HR 1.021, 95% CI 1.000-1.043, P = 0.042), APASL ACLF Research Consortium (AARC) score (HR 1.498, 95% CI 1.312-1.710, P < 0.001), and sarcopenia (HR 1.802, 95% CI 1.062-3.060, P = 0.029) were independently associated with increased 90-day mortality. Subgroup analysis of male patients with HBV-ACLF revealed that myosteatosis (HR 2.119, 95% CI 1.101-4.078, P = 0.025) was promising prognostic factors for 90-day mortality after being adjusted for ascites, acute kidney injury, AARC score, and sarcopenia. Myosteatosis is predictive of short-term outcomes in male patients with HBV-ACLF. Our results emphasise the importance of focusing on muscle fat infiltration in patients with HBV-ACLF. Further studies are warranted to investigate the underlying mechanisms and potential therapies for myosteatosis.

Low serum manganese as a noninvasive marker predicting the presence of myosteatosis among hospitalized patients with cirrhosis

Emerging evidence expands on a close connection between trace elements and muscular abnormalities, mostly focusing on sarcopenia. We hypothesized an association between concentrations of serum trace elements and myosteatosis, given that myosteatosis has a more pronounced clinical implication relative to sarcopenia, but there is a paucity of data in patients with cirrhosis. Consecutive patients were hospitalized for cirrhosis-associated complications. Serum trace elements (zinc, copper, manganese [Mn], magnesium, calcium, and iron) were measured by inductively coupled plasma mass spectrometry. The presence of myosteatosis was defined according to computed tomography-demarcated intramuscular adipose tissue content. In total, the 295 patients with cirrhosis analyzed had a median age of 63 years and 53.6% were male. Among them, 42 patients presented with myosteatosis (14.2%) and concomitant higher Model for End-stage Liver Disease-Sodium and triglyceride concentrations and lower neutrophil counts and serum Mn concentrations (all P < .05). No differences were found regarding other 5 trace elements in patients with versus without myosteatosis. The median serum Mn concentrations were 1.16 µg/L, and this population was categorized into high-Mn and low-Mn groups. The proportion of myosteatosis was significantly lower in high-Mn group than that in low-Mn group (8.1% vs 20.4%, P < .001). Univariable binary logistic regression indicated that low Mn was associated with myosteatosis (odds ratio, 2.906; 95% confidence interval, 1.424-5.932; P = .003) in the context of cirrhosis. This result was validated according to multivariable analysis by adjusting for confounding factors. In conclusion, low serum Mn can be predictive of myosteatosis, a novel muscular abnormality representing more clinical relevance and close relation to inferior outcomes among cirrhosis.

The adverse impact of perioperative body composition abnormalities on outcomes after split liver transplantation: a multicenter retrospective cohort study

BACKGROUND

Split liver transplantation (SLT) increases graft availability, but it's safe and effective utilization is insufficiently documented. This study aimed to investigate the association between perioperative body composition abnormalities and outcomes in adult SLT.

MATERIALS AND METHODS

Two hundred forty recipients who underwent SLT in three centers were enrolled in this retrospective cohort study. Body composition abnormalities including sarcopenia, myosteatosis, visceral obesity, and sarcopenic obesity were evaluated at baseline and 1 month after surgery using computed tomography. Their impact on outcomes including early allograft dysfunction, early complications, ICU stay, graft regeneration rate, and survival was analyzed.

RESULTS

Recipients with sarcopenia or myosteatosis had a higher risk of early allograft dysfunction, higher early complication rate, and longer length of ICU stay (all P <0.05), while there was no difference in graft regeneration rate. Recipient and graft survival were significantly worse for recipients with body composition abnormalities (all P <0.05). In multivariable Cox-regression analysis, sarcopenia [hazard ratio (HR)=1.765, P =0.015], myosteatosis (HR=2.066, P =0.002), and visceral obesity (HR=1.863, P =0.008) were independently associated with shorter overall survival. Piling up of the three factors increased the mortality risk stepwise ( P <0.001). Recipients experienced skeletal muscle loss and muscle fat infiltration 1 month after surgery. Postoperative worsening sarcopenia (HR=2.359, P =0.009) and myosteatosis (HR=1.878, P =0.026) were also identified as independent risk factors for mortality.

CONCLUSION

Sarcopenia, myosteatosis, and their progression negatively affect outcomes including early allograft dysfunction, early complications, ICU stay and survival after SLT. Systemic evaluation and dynamic monitoring of body composition are valuable.

Prognostic Value of Myosteatosis and Creatinine-to-Cystatin C Ratio in Patients with Pancreatic Cancer Who Underwent Radical Surgery

BACKGROUND

Myosteatosis is correlated with poor prognosis in some malignancies. The creatinine-to-cystatin ratio (CCR) is revealed to predict gastric cancer prognosis. However, the prognostic abilities of CCR and the combination of CCR and myosteatosis in patients with pancreatic cancer (PC) who underwent radical surgery remains unclear.

METHODS

The retrospective cohort study included 215 patients with PC who underwent radical surgery (January 2016-October 2021). Clinicopathological and serological data were collected on admission. Myosteatosis and other body composition indices were assessed by using computed tomography. The cutoff value of CCR was determined by using the Youden index. Risk factors responsible for poor overall survival (OS) and disease-free survival (DFS) were determined by the Cox proportional hazards model.

RESULTS

The myosteatosis group included 104 patients (average age, 61.3 ± 9.1 years). The best cutoff value for CCR was 1.09. CCR ≤ 1.09 was an independent predictive biomarker inversely corelated with OS (P = 0.036). Myosteatosis was an independent risk factor associated with OS and DFS (P = 0.032 and P = 0.004, respectively). Patients with concomitant myosteatosis and CCR ≤ 1.09 had the worst OS (P = 0.016).

CONCLUSIONS

Myosteatosis and CCR are prognostic biomarkers for survival in PC patients who underwent radical surgery. Patients with the coexistence of myosteatosis and CCR ≤ 1.09 deserve more attention.

Imaging-based diagnosis of sarcopenia for transplant-free survival in primary sclerosing cholangitis

BACKGROUND

Imaging-based assessment of sarcopenia is a well-validated prognostic tool for patients with chronic liver disease. However, little is known about its value in patients with primary sclerosing cholangitis (PSC). This cross-sectional study aimed to investigate the predictive value of the cross-sectional imaging-based skeletal muscle index (SMI) for transplant-free survival (TFS) in patients with PSC.

METHODS

A total of 95 patients with PSC who underwent abdominal cross-sectional imaging between 2008 and 2022 were included in this retrospective study. SMI was measured at the third lumbar vertebra level (L3-SMI). The cut-off values to define sarcopenia were < 50 cm²/m² in male patients and < 39 cm²/m² in female patients. The primary outcome of this study was TFS, which was defined as survival without liver transplantation or death from any cause.

RESULTS

Our study indicates that L3-SMI sarcopenia impairs TFS in patients with PSC (5-year TFS: 33.9% vs. 83.3%, p = 0.001, log-rank test). L3-SMI sarcopenia was independently associated with reduced TFS via multivariate Cox regression analysis (HR = 2.749; p = 0.028). Body mass index reduction > 10% at 12 months, which is used as MELD standard exception (SE) criterion in Eurotransplant (in Germany only until September 2023), was not significantly associated with TFS in the multivariate Cox regression analysis (HR = 1.417; p = 0.330). Substitution of BMI reduction with L3-SMI in the German SE criteria improved the predictive accuracy of TFS compared to the established SE criteria (multivariable Cox regression analysis: HR = 4.007, p < 0.001 vs. HR = 1.691, p = 0.141).

CONCLUSION

Imaging-based diagnosis of sarcopenia via L3-SMI is associated with a low TFS in patients with PSC and may provide additional benefits as a prognostic factor in patient selection for liver transplantation.

Advances in sarcopenia: mechanisms, therapeutic targets, and intervention strategies

Sarcopenia is a multifactorial condition characterized by loss of muscle mass. It poses significant health risks in older adults worldwide. Both pharmacological and non-pharmacological approaches are reported to address this disease. Certain dietary patterns, such as adequate energy intake and essential amino acids, have shown positive outcomes in preserving muscle function. Various medications, including myostatin inhibitors, growth hormones, and activin type II receptor inhibitors, have been evaluated for their effectiveness in managing sarcopenia. However, it is important to consider the variable efficacy and potential side effects associated with these treatments. There are currently no drugs approved by the Food and Drug Administration for sarcopenia. The ongoing research aims to develop more effective strategies in the future. Our review of research on disease mechanisms and drug development will be a valuable contribution to future research endeavors.

Enhancing ACLF prediction by integrating sarcopenia assessment and frailty in liver transplant candidates on the waiting list

Background & Aims

Malnutrition, sarcopenia, and frailty are prevalent in cirrhosis. We aimed to assess the correlation between assessment tools for malnutrition, sarcopenia, and frailty in patients on the liver transplant (LT) waiting list (WL), and to identify a predictive model for acute-on-chronic liver failure (ACLF) development.

Methods

This prospective single-center study enrolled consecutive patients with cirrhosis on the WL for LT (May 2019-November 2021). Assessments included subjective global assessment, CT body composition, skeletal muscle index (SMI), ultrasound thigh muscle thickness, sarcopenia HIBA score, liver frailty index (LFI), hand grip strength, and 6-minute walk test at enrollment. Correlations were analyzed using Pearson's correlation. Competing risk regression analysis was used to assess the predictive ability of the liver- and functional physiological reserve-related variables for ACLF.

Results

A total of 132 patients, predominantly with decompensated cirrhosis (87%), were included. Our study revealed a high prevalence of malnutrition (61%), sarcopenia (61%), visceral obesity (20%), sarcopenic visceral obesity (17%), and frailty (10%) among participants. Correlations between the assessment tools for sarcopenia and frailty were poor. Sarcopenia by SMI remained prevalent when frailty assessments were not usable. After a median follow-up of 10 months, 39% of the patients developed ACLF on WL, while 28% experienced dropouts without ACLF. Multivariate analysis identified MELD-Na, SMI, and LFI as independent predictors of ACLF on the WL. The predictive model MELD-Na-sarcopenia-LFI had a C-statistic of 0.85.

Conclusions

The poor correlation between sarcopenia assessment tools and frailty underscores the importance of a comprehensive evaluation. The SMI, LFI, and MELD-Na independently predicted ACLF development in WL. These findings enhance our understanding of the relationship between sarcopenia, frailty, and ACLF in patients awaiting LT, emphasizing the need for early detection and intervention to improve WL outcomes.

Impact and implications

The relationship between sarcopenia and frailty assessment tools, as well as their ability to predict acute-on-chronic liver failure (ACLF) in patients on the liver transplant (LT) waiting list (WL), remains poorly understood. Existing objective frailty screening tests have limitations when applied to critically ill patients. The correlation between sarcopenia and frailty assessment tools was weak, suggesting that they may capture different phenotypes. Sarcopenia assessed by skeletal muscle index, frailty evaluated using the liver frailty index, and the model for end-stage liver disease-Na score independently predicted the development of ACLF in patients on the WL. Our findings support the integration of liver frailty index and skeletal muscle index assessments at the time of inclusion on the WL for LT. This combined approach allows for the identification of a specific patient subgroup with an increased susceptibility to ACLF, underscoring the importance of early implementation of targeted treatment strategies to improve outcomes for patients awaiting LT.

Calcification of the visceral aorta and celiac trunk is associated with renal and allograft outcomes after deceased donor liver transplantation

PURPOSE

Atherosclerosis affects clinical outcomes in the setting of major surgery. Here we aimed to investigate the prognostic role of visceral aortic (VAC), extended visceral aortic (VAC+), and celiac artery calcification (CAC) in the assessment of short- and long-term outcomes following deceased donor orthotopic liver transplantation (OLT) in a western European cohort.

METHODS

We retrospectively analyzed the data of 281 consecutive recipients who underwent OLT at a German university medical center (05/2010-03/2020). The parameters VAC, VAC+, or CAC were evaluated by preoperative computed tomography-based calcium quantification according to the Agatston score.

RESULTS

Significant VAC or CAC were associated with impaired postoperative renal function (p = 0.0016; p = 0.0211). Patients with VAC suffered more frequently from early allograft dysfunction (EAD) (38 vs 26%, p = 0.031), while CAC was associated with higher estimated procedural costs (p = 0.049). In the multivariate logistic regression analysis, VAC was identified as an independent predictor of EAD (2.387 OR, 1.290-4.418 CI, p = 0.006). Concerning long-term graft and patient survival, no significant difference was found, even though patients with calcification showed a tendency towards lower 5-year survival compared to those without (VAC: 65 vs 73%, p = 0.217; CAC: 52 vs 72%, p = 0.105). VAC+ failed to provide an additional prognostic value compared to VAC.

CONCLUSION

This is the first clinical report to show the prognostic role of VAC/CAC in the setting of deceased donor OLT with a particular value in the perioperative phase. Further studies are warranted to validate these findings. CT computed tomography, OLT orthotopic liver transplantation.

Osteopenia is associated with inferior survival in patients undergoing partial hepatectomy for hepatocellular carcinoma

Osteopenia is known to be associated with clinical frailty which is linked to inferior outcomes in various clinical scenarios. However, the exact prognostic value of osteopenia in patients undergoing curative intent-surgery for hepatocellular carcinoma (HCC) is not completely understood. This retrospective study was conducted in a cohort of 151 patients who underwent partial hepatectomy for HCC in curative intent at a German university medical center (05/2008-12/2019). Preoperative computed tomography-based segmentation was used to assess osteopenia, and the prognostic impact of pathological changes in bone mineral density (BMD) on perioperative morbidity, mortality, and long-term oncological outcome was analyzed. Five-year overall survival of osteopenic patients was significantly worse compared to those with normal BMD (29% vs. 65%, p = 0.014). In line with this, the probability of disease-free survival at 5 years was significantly worse for patients with osteopenia (21% vs. 64%, p = 0.005). In our multivariable model, osteopenia was confirmed as an independent risk-factor for inferior overall survival (Hazard-ratio 7.743, p = 0.002). Concerning perioperative complications, osteopenic patients performed slightly worse, even though no statistical difference was detected (Clavien-Dindo ≥ 3b; 21% vs. 9%, p = 0.139). The present study confirms osteopenia as an independent risk-factor for inferior survival in patients undergoing partial hepatectomy for HCC in a European cohort. Further studies are warranted to validate these findings.