| 1. |
- Bui, Anh T., et al.
(author)
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Reduced metabolic flexibility is a predictor of weight gain among liver transplant recipients
- 2023
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In: Liver transplantation. - : LIPPINCOTT WILLIAMS & WILKINS. - 1527-6465 .- 1527-6473.
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Journal article (peer-reviewed)abstract
- Metabolic flexibility is the ability to match biofuel availability to utilization and is inversely associated with increased metabolic burden among liver transplant (LT) recipients. The present study evaluated the impact of metabolic flexibility on weight gain following LT. LT recipients were enrolled prospectively (n = 47) and followed for 6 months. Metabolic flexibility was measured using whole-room calorimetry and is expressed as a respiratory quotient (RQ). Peak RQ represents maximal carbohydrate metabolism and occurs in the post-prandial state, while trough RQ represents maximal fatty acid metabolism occurring in the fasted state. The clinical, metabolic, and laboratory characteristics of the study cohort of lost weight (n = 14) and gained weight (n = 33) were similar at baseline. Patients who lost weight were more likely to reach maximal RQ (maximal carbohydrate oxidation) early and rapidly transitioned to trough RQ (maximal fatty acid oxidation). In contrast, patients who gained weight had delayed time to peak RQ and trough RQ. In multivariate modeling, time to peak RQ (& beta;-coefficient 0.509, p = 0.01), time from peak RQ to trough RQ (& beta;-coefficient 0.634, p = 0.006), and interaction between time to peak RQ to trough RQ and fasting RQ (& beta;-coefficient 0.447, p = 0.02) directly correlated with the severity of weight gain. No statistically significant relationship between peak RQ, trough RQ, and weight change was demonstrated. Inefficient transition between biofuels (carbohydrates and fatty acids) is associated with weight gain in LT recipients that is independent of clinical metabolic risk. These data offer novel insight into the physiology of obesity after LT with the potential to develop new diagnostics and therapeutics.
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| 2. |
- Chakravarthy, Manu V., et al.
(author)
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Harnessing Muscle-Liver Crosstalk to Treat Nonalcoholic Steatohepatitis
- 2020
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In: Frontiers in Endocrinology. - : Frontiers Media S.A.. - 1664-2392. ; 11
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Research review (peer-reviewed)abstract
- Non-alcoholic fatty liver disease (NAFLD) has reached epidemic proportions, affecting an estimated one-quarter of the worlds adult population. Multiple organ systems have been implicated in the pathophysiology of NAFLD; however, the role of skeletal muscle has until recently been largely overlooked. A growing body of evidence places skeletal muscle-via its impact on insulin resistance and systemic inflammation-and the muscle-liver axis at the center of the NAFLD pathogenic cascade. Population-based studies suggest that sarcopenia is an effect-modifier across the NAFLD spectrum in that it is tightly linked to an increased risk of non-alcoholic fatty liver, non-alcoholic steatohepatitis (NASH), and advanced liver fibrosis, all independent of obesity and insulin resistance. Longitudinal studies suggest that increases in skeletal muscle mass over time may both reduce the incidence of NAFLD and improve preexisting NAFLD. Adverse muscle composition, comprising both low muscle volume and high muscle fat infiltration (myosteatosis), is highly prevalent in patients with NAFLD. The risk of functional disability conferred by low muscle volume in NAFLD is further exacerbated by the presence of myosteatosis, which is twice as common in NAFLD as in other chronic liver diseases. Crosstalk between muscle and liver is influenced by several factors, including obesity, physical inactivity, ectopic fat deposition, oxidative stress, and proinflammatory mediators. In this perspective review, we discuss key pathophysiological processes driving sarcopenia in NAFLD: anabolic resistance, insulin resistance, metabolic inflexibility and systemic inflammation. Interventions that modify muscle quantity (mass), muscle quality (fat), and physical function by simultaneously engaging multiple targets and pathways implicated in muscle-liver crosstalk may be required to address the multifactorial pathogenesis of NAFLD/NASH and provide effective and durable therapies.
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| 3. |
- Linge, Jennifer, et al.
(author)
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Adverse muscle composition is a significant risk factor for all-cause mortality in NAFLD
- 2023
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In: JHEP Reports. - : ELSEVIER. - 2589-5559. ; 5:3
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Journal article (peer-reviewed)abstract
- Background & Aims: Adverse muscle composition (MC) (i.e., low muscle volume and high muscle fat) has previously been linked to poor functional performance and comorbidities in non-alcoholic fatty liver disease (NAFLD). In this study we aimed to investigate associations of all-cause mortality with liver fat, NAFLD, and MC in the UK Biobank imaging study.Methods: Magnetic resonance images of 40,174 participants were analyzed for liver proton density fat fraction (PDFF), thigh fat-free muscle volume (FFMV) z-score, and muscle fat infiltration (MFI) using the AMRA (R) Researcher. Participants with NAFLD were sex-, age-, and BMI-matched to participants without NAFLD with low alcohol consumption. Adverse MC was identified using previously published cut-offs. All-cause mortality was investigated using Cox regression. Models within NAFLD were crude and subsequently adjusted for sex, age, BMI (M1), hand grip strength, physical activity, smoking, alcohol (M2), and previous cancer, coronary heart disease, type 2 diabetes (M3).Results: A total of 5,069 participants had NAFLD. During a mean (+/- SD) follow-up of 3.9 (+/- 1.4) years, 150 out of the 10,138 participants (53% men, age 64.4 [+/- 7.6] years, BMI 29.7 [+/- 4.4] kg/m2) died. In the matched dataset, neither NAFLD nor liver PDFF were associated with all-cause mortality, while all MC variables achieved significance. Within NAFLD, adverse MC, MFI and FFMV z-score were significantly associated with all-cause mortality and remained so in M1 and M2 (crude hazard ratios [HRs] 2.84, 95% CI 1.70-4.75, p <0.001; 1.15, 95% CI 1.07-1.24, p <0.001; 0.70, 95% CI 0.55-0.88, p <0.001). In M3, the rela-tionship was attenuated for adverse MC and FFMV z-score (adjusted HRs 1.72, 95% CI 1.00-2.98, p = 0.051; 0.77, 95% CI 0.58-1.02, p = 0.069) but remained significant for MFI (adjusted HR 1.13, 95% CI 1.01-1.26, p = 0.026).Conclusions: Neither NAFLD nor liver PDFF was predictive of all-cause mortality. Adverse MC was a strong predictor of all -cause mortality in individuals with NAFLD.Impact and implications: Individuals with fatty liver disease and poor muscle health more often suffer from poor functional performance and comorbidities. This study shows that they are also at a higher risk of dying. The study results indicate that measuring muscle health (the patients muscle volume and how much fat they have in their muscles) could help in the early detection of high-risk patients and enable targeted preventative care.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of European Association for the Study of the Liver (EASL). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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| 4. |
- Linge, Jennifer, et al.
(author)
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Adverse muscle composition predicts all-cause mortality in the UK Biobank imaging study
- 2021
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In: Journal of Cachexia, Sarcopenia and Muscle. - : Wiley. - 2190-5991 .- 2190-6009. ; 12:6, s. 1513-1526
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Journal article (peer-reviewed)abstract
- Background Adverse muscle composition (MC) as measured by magnetic resonance imaging has previously been linked to poor function, comorbidity, and increased hospitalization. The aim of this study was to investigate if adverse MC predicts all-cause mortality using data from UK Biobank. Methods There were 40 178 participants scanned using a 6 min magnetic resonance imaging protocol. Images were analysed for thigh fat-tissue free muscle volume and muscle fat infiltration (MFI) using AMRA (R) Researcher (AMRA Medical, Linkoping, Sweden). For each participant, a sex, weight, and height invariant muscle volume z-score was calculated. Participants were partitioned into four MC groups: (i) normal MC, (ii) only low muscle volume [<25th percentile for muscle volume z-score (population wide)], (iii) only high MFI [>75th percentile (population wide, sex-specific)], and (iv) adverse MC (low muscle volume z-score and high MFI). Association of MC groups with mortality was investigated using Cox proportional-hazard modelling with normal MC as referent (unadjusted and adjusted for low hand grip strength, sex, age, body mass index, previous diagnosis of disease (cancer, type 2 diabetes and coronary heart disease), lifestyle, and socioeconomic factors (smoking, alcohol consumption, physical activity, and Townsend deprivation index). Results Muscle composition measurements were complete for 39 804 participants [52% female, mean (SD) age 64.2 (7.6) years and body mass index 26.4 (4.4) kg/m(2)]. Three hundred twenty-eight deaths were recorded during a follow-up period of 2.9 (1.4) years after imaging. At imaging, adverse MC was detected in 10.5% of participants. The risk of death from any cause in adverse MC compared with normal MC was 3.71 (95% confidence interval 2.81-4.91, P < 0.001). Only low muscle volume and only high MFI were independently associated with all-cause mortality [1.58 (1.13-2.21), P = 0.007, and 2.02 (1.51-2.71), P < 0.001, respectively]. Adjustment of low hand grip strength [1.77 (1.28-2.44), P < 0.001] did not attenuate the associations with any of the MC groups. In the fully adjusted model, adverse MC and only high MFI remained significant (P P = 0.020) while the association with only low muscle volume was attenuated to non-significance (P = 0.560). The predictive performance of adverse MC [1.96 (1.42-2.71), P < 0.001] was comparable with that of previous cancer diagnosis [1.93 (1.47-2.53), P < 0.001] and smoking [1.71 (1.02-2.84), P = 0.040]. Low hand grip strength was borderline non-significant [1.34 (0.96-1.88), P = 0.090]. Conclusions Adverse MC was a strong and independent predictor of all-cause mortality. Sarcopenia guidelines can be strengthened by including cut-offs for myosteatosis enabling detection of adverse MC.
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| 7. |
- Siddiqui, Mohammad S., et al.
(author)
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Differential fuel utilization in liver transplant recipients and its relationship with non-alcoholic fatty liver disease
- 2022
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In: Liver international (Print). - : Wiley. - 1478-3223 .- 1478-3231. ; 42:6, s. 1401-1409
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Journal article (peer-reviewed)abstract
- 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.
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| 8. |
- Siddiqui, Mohammad Shadab, et al.
(author)
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Saroglitazar improves nonalcoholic fatty liver disease and metabolic health in liver transplant recipients
- 2023
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In: Liver transplantation. - : LIPPINCOTT WILLIAMS & WILKINS. - 1527-6465 .- 1527-6473. ; 29:9, s. 979-986
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Journal article (peer-reviewed)abstract
- NAFLD is common after liver transplantation (LT) and is associated with an increased metabolic burden. Currently, there is a paucity of investigations into the treatment of post-LT NAFLD. In the present study, we evaluated the safety and efficacy of saroglitazar, a novel dual peroxisome proliferator-associated receptor & alpha;/& gamma; agonist, on the treatment of post-LT NAFLD and metabolic burden. This is a phase 2A, single-center, open-label, single-arm study in which patients with post-LT NAFLD received saroglitazar magnesium 4 mg daily for 24 weeks. NAFLD was defined by a controlled attenuation parameter & GE;264 dB/m. The primary endpoint was the reduction in liver fat as measured by MRI proton density fat fraction (MRI-PDFF). Secondary MRI-based metabolic endpoints included visceral adipose tissue, abdominal subcutaneous adipose tissue volumes, muscle fat infiltration, and fat-free muscle volume. Saroglitazar treatment led to a reduction in MRI-PDFF from 10.3 & PLUSMN;10.5% at baseline to 8.1 & PLUSMN;7.6%. A relative 30% reduction from baseline MRI-PDFF value was noted in 47% of all patients and 63% of patients with baseline MRI-PDFF >5%. Reduction in serum alkaline phosphatase was an independent predictor of MRI-PDFF response. Saroglitazar did not decrease fat-free muscle volume nor increase muscle fat infiltration, but did lead to a mild increase in visceral adipose tissue and abdominal subcutaneous adipose tissue. The study drug was well tolerated and a mild nonsignificant increase in serum creatinine was noted. Saroglitazar did not affect the weight. The study provides preliminary data demonstrating the safety and metabolic benefits of saroglitazar in LT recipients and underscores the importance of future studies to establish its efficacy after LT.
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