Fatty Liver Index and Skeletal Muscle Density

Moderate-Intensity Exercise Enhances Mitochondrial Biogenesis Markers in the Skeletal Muscle of a Mouse Model Affected by Diet-Induced Obesity

Skeletal muscle is composed of bundles of muscle fibers with distinctive characteristics. Oxidative muscle fiber types contain higher mitochondrial content, relying primarily on oxidative phosphorylation for ATP generation. Notably, as a result of obesity, or following prolonged exposure to a high-fat diet, skeletal muscle undergoes a shift in fiber type toward a glycolytic type. Mitochondria are highly dynamic organelles, constantly undergoing mitochondrial biogenesis and dynamic processes. Our study aims to explore the impact of obesity on skeletal muscle mitochondrial biogenesis and dynamics and also ascertain whether the skeletal muscle fiber type shift occurs from the aberrant mitochondrial machinery. Furthermore, we investigated the impact of exercise in preserving the oxidative muscle fiber types despite obesity. Mice were subjected to a normal standard chow and water or high-fat diet with sugar water (HFS) with or without exercise training. After 12 weeks of treatment, the HFS diet resulted in a noteworthy reduction in the markers of mitochondrial content, which was recovered by exercise training. Furthermore, higher mitochondrial biogenesis markers were observed in the exercised group with a subsequent increase in the mitochondrial fission marker. In conclusion, these findings imply a beneficial impact of moderate-intensity exercise on the preservation of oxidative capacity in the muscle of obese mouse models.

Effects of high-intensity training on fatty infiltration in paraspinal muscles in elderly males with osteosarcopenia - the randomized controlled FrOST study

BACKGROUND

Osteosarcopenia is a common geriatric syndrome with an increasing prevalence with age, leading to secondary diseases and complex consequences such as falls and fractures, as well as higher mortality and frailty rates. There is a great need for prevention and treatment strategies.

METHODS

In this analysis, we used magnetic resonance imaging (MRI) data from the randomised controlled FrOST trial, which enrolled community-dwelling osteosarcopenic men aged > 72 years randomly allocated to 16 months of twice-weekly high-intensity resistance training (HIRT) or a non-training control group. MR Dixon imaging was used to quantify the effects of HIRT on muscle fat infiltration in the paraspinal muscles, determined as changes in muscle tissue, fat faction and intermuscular adipose tissue (IMAT) in the erector spinae and psoas major muscles. Intention-to-treat analysis with multiple imputation was used to analyse the data set.

RESULTS

After 16 months of intervention, 15 men from the HIRT and 16 men from the CG were included in the MRI analysis. In summary, no positive effects on the fat infiltration of the erector spinae and psoas major muscles were observed.

CONCLUSIONS

The previously reported positive effects on lumbar spine bone mineral density (BMD) suggest that mechanotransduction induces tropic effects on bone, but that fat infiltration of the erector spinae and psoas major muscles are either irreversible or, for some unknown reason, resistant to exercise. Because of the beneficial effects on spinal BMD, HIRT is still recommended in osteosarcopenic older men, but further research is needed to confirm appropriate age-specific training exercises for the paraspinal muscles. The potential of different MRI sequences to quantify degenerative and metabolic changes in various muscle groups must be better characterized.

TRIAL REGISTRATIONS

FrOST was approved by the University Ethics Committee of the Friedrich-Alexander University of Erlangen-Nürnberg (number 67_15b and 4464b) and the Federal Office for Radiation Projection (BfS, number Z 5-2,246,212 - 2017-002). Furthermore, it fully complies with the Declaration of Helsinki and is registered at ClinicalTrials.gov: NCT03453463 (05/03/2018). JAMA 310:2191-2194, 2013.

Fatty liver index (FLI): more than a marker of hepatic steatosis

Fatty liver index (FLI) was developed as a simple and accurate marker of hepatic steatosis. FLI is derived from an algorithm based on body mass index, waist circumference, and levels of triglycerides and gamma-glutamyltransferase, and it is widely used in clinical and epidemiological studies as a screening tool for discriminating between healthy and nonalcoholic fatty liver disease (NAFLD) subjects. However, a systematic review of the literature regarding FLI revealed that this index has more extensive relationships with biochemical and physiological parameters. FLI is associated with key parameters of lipid, protein and carbohydrate metabolism, hormones, vitamins and markers of inflammation, or oxidative stress. FLI can be a predictor or risk factor for a number of metabolic and nonmetabolic diseases and mortality. FLI is also used as an indicator for determining the effects of health-related prevention interventions, medications, and toxic substances on humans. Although in most cases, the exact mechanisms underlying these associations have not been fully elucidated, they are most often assumed to be mediated by insulin resistance, inflammation, and oxidative stress. Thus, FLI may be a promising marker of metabolic health due to its multiple associations with parameters of physiological and pathological processes. In this context, the present review summarizes the data from currently available literature on the associations between FLI and biochemical variables and physiological functions. We believe that this review will be of interest to researchers working in this area and can provide new perspectives and directions for future studies on FLI.

Obesity and sarcopenic obesity characterized by low-grade inflammation are associated with increased risk for major depression in women

Background

We aimed to determine women's risk of major depressive disorder (MDD) in relation to obesity phenotypes characterized by levels of circulating high-sensitivity C-reactive protein (hsCRP).

Methods

This population-based retrospective cohort study comprised 808 women (ages 20-84 y) recruited 1994-1997 and followed for a median 16.1 y (IQR 11.9-16.8). At baseline, body fat and lean tissue mass were measured by whole body dual-energy x-ray absorptiometry (DXA). Obesity was identified as high fat mass index (>12.9 kg/m2), body fat percentage (≥35%) and body mass index (≥30 kg/m2); sarcopenic obesity referred to a high ratio fat mass/fat-free mass (≥0.80). Systemic inflammation was operationalized as serum hsCRP concentration in the upper tertile (>2.99 mg/L). Obesity phenotypes were: non-obese + lowCRP, non-obese + highCRP, obese + lowCRP, and obese + highCRP. During follow-up, the Structured Clinical Interview for DSM-IV-TR (SCID-I/NP) was used to identify lifetime history of MDD and age of onset. Poisson regression models were used to estimate the MDD rate for each obesity phenotype during follow-up. Demographic, health and lifestyle factors were tested as potential confounders.

Results

During 11,869 p-y of follow-up, 161 (19.9%) women experienced an MDD episode. For obesity phenotypes based on fat mass index, models adjusted for baseline age and prior MDD, and non-obese + lowCRP as reference, RR for non-obese + highCRP was 1.21 (95% CI 0.80, 1.82), obese + lowCRP 1.46 (0.86, 2.47) and obese + highCRP 1.56 (1.03, 2.37). Patterns were similar for obesity by body fat percentage, body mass index and sarcopenic obesity.

Conclusion

Consistently across different obesity definitions, this longitudinal study reports that women with both obesity and systemic inflammation are at increased risk of subsequent MDD. Future research should examine whether tackling this metabolically unhealthy obesity type - through, for example, lifestyle or medication approaches - can reduce depression risk.

Osteosarcopenia in NAFLD/MAFLD: An Underappreciated Clinical Problem in Chronic Liver Disease

Chronic liver disease (CLD), including non-alcoholic fatty liver disease (NAFLD) and its advanced form, non-alcoholic steatohepatitis (NASH), affects a significant portion of the population worldwide. NAFLD is characterised by fat accumulation in the liver, while NASH is associated with inflammation and liver damage. Osteosarcopenia, which combines muscle and bone mass loss, is an emerging clinical problem in chronic liver disease that is often underappreciated. The reductions in muscle and bone mass share several common pathophysiological pathways; insulin resistance and chronic systemic inflammation are the most crucial predisposing factors and are related to the presence and gravity of NAFLD and to the worsening of the outcome of liver disease. This article explores the relationship between osteosarcopenia and NAFLD/MAFLD, focusing on the diagnosis, prevention and treatment of this condition in patients with CLD.

Dynapenia, Muscle Quality, and Hepatic Steatosis in Patients with Obesity and Sarcopenic Obesity

Accumulating evidence supports a connection between sarcopenic obesity (SO) and NAFLD. The extent to which fatty liver contributes to impaired muscle contractility is not yet well established. The aim of our study was to investigate the effect of NAFLD on dynapenia in patients with SO. In this study, 71 non-diabetic subjects (age 55 (7.8) years, BMI 35.2 kg/m² (32.6-38.8)) were classified as having SO and non-sarcopenic obesity (NSO). SO patients displayed worse serum lipid profiles, higher body fat, and lower skeletal muscle mass (both total and appendicular) than NSO patients, despite the absence of any significant differences in body weight, glycometabolic parameters, and hepatic steatosis prevalence. A positive correlation between disposition index and muscle quality index (MQI) (r = 0.393, p = 0.013) emerged after controlling for menopause and body fat percentage. Based on multiple linear regression analysis, MQI was significantly positively associated with the disposition index (β: 0.059, SE: 0.002, p = 0.006) after adjustment for menopause, body fat percentage, and the presence of hepatic steatosis according to the hepatorenal index (HRI). Similar findings emerged when including liver enzyme levels in place of hepatic steatosis. Muscle quality was positively associated with β-cell function corrected for insulin resistance among patients with obesity and sarcopenic obesity, irrespective of the presence of fatty liver disease.

Effect of progressive resistance training with weight loss compared with weight loss alone on the fatty liver index in older adults with type 2 diabetes: secondary analysis of a 12-month randomized controlled trial

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent (~75%) in people with type 2 diabetes (T2D). Since exercise and weight loss (WL) are recommended for the management of both NAFLD and T2D, this study examined whether progressive resistance training (PRT) plus WL could lead to greater improvements in the fatty liver index (FLI), an indicator of NAFLD, compared with WL alone in older adults with T2D.

RESEARCH DESIGN AND METHODS

This study represents a secondary analysis of a 12-month, two-arm randomised controlled trial including 36 overweight and obese adults (60-80 years) with T2D randomly allocated to supervised PRT plus WL (hypocaloric diet) (n=19) or WL plus sham (stretching) (n=17) for 6 months (phase I), followed by 6-months home-based training with ad libitum diet (phase II). FLI, which is an algorithm based on waist circumference, body mass index, triglycerides and gamma-glutamyl transferase, was assessed at baseline and every 3 months. Linear mixed models were used to analyse between-group differences over time, adjusting for baseline values.

RESULTS

At baseline, the mean±SD FLI was 76.6±18.5 and the likelihood of NAFLD (FLI >60) in all participants was 86%. Following phase I, both groups had similar statistically significant improvements in FLI (mean change (95% CI): PRT+WL, -12 (-20 to -4); WL, -9 (-15 to -4)), with no significant between-group difference. After the subsequent 6-month home-based phase, the improvements in FLI tended to persist in both groups (PRT+WL, -7 (-11 to -2); WL, -4 (-10 to 1)), with no between-group differences.

CONCLUSIONS

In older overweight adults with T2D, PRT did not enhance the benefits of WL on FLI, a predictor of NAFLD.

TRIAL REGISTRATION NUMBER

ACTRN12622000640707.

Sex- and region-specific associations of skeletal muscle mass with metabolic dysfunction-associated fatty liver disease

INTRODUCTION

Metabolic dysfunction-associated fatty liver disease (MAFLD) is known to be the most common chronic liver disease worldwide, and accumulating evidence suggests that skeletal muscle might play an important role in metabolic health. However, the association between skeletal muscle and MAFLD is poorly understood so far. Therefore, we aimed to evaluate the associations of skeletal muscle with MAFLD and significant fibrosis.

METHODS

A cross-sectional analysis was conducted using data obtained from the 2017-2018 US National Health and Nutrition Examination Survey. The whole-body, appendicular, and trunk skeletal muscle mass index (SMI) were assessed by dual-energy x-ray absorptiometry. MAFLD and significant fibrosis were assessed by transient elastography. Survey-weight adjusted multivariable logistic regressions were used to determine the associations. The area under the receiver operating characteristic curve (AUC) and variable importance scores from the random forest and logistic regression model were calculated to assess the predictive capability of variables and models.

RESULTS

Of the 2065 participants, those with appendicular SMI in the highest quartile were associated with a lower risk for MAFLD in both sexes (male, OR[95%CI]: 0.46 [0.25~0.84]; female, OR[95%CI]: 0.32 [0.13~0.82]), but with a significantly different scale of the associations between sexes (P _interaction = 0.037). However, females with trunk SMI in the highest quartile had an increased risk of significant fibrosis (OR[95%CI]: 7.82 [1.86~32.77]). Trunk SMI and appendicular SMI ranked the third contributor to MAFLD in random forest and logistic regression models, respectively. Taking appendicular and trunk SMI into consideration, the AUCs for MAFLD were 0.890 and 0.866 in random forest and logistic regression models, respectively.

DISCUSSION

The distribution of skeletal muscle mass differently affects MAFLD and significant fibrosis in the sex groups. Higher appendicular skeletal muscle mass was associated with a lower risk of MAFLD, while the risk of significant fibrosis in females was increased with the trunk skeletal muscle mass.