muscle density
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AbstractAccumulation of fat in the liver and skeletal muscle is associated with obesity and poor health outcomes. Liver steatosis is a characteristic of non-alcoholic fatty liver disease (NAFLD) and myosteatosis, of poor muscle quality in sarcopenia. In this study of 403 men (33–96 years), we investigated associations between the fatty liver index (FLI) and muscle density, as markers of fat accumulation in these organs. We also investigated associations between the FLI and parameters of sarcopenia, including DXA-derived appendicular lean mass (ALM) and handgrip strength by dynamometry. Muscle density was measured using pQCT at the radius and tibia. FLI was calculated from BMI, waist circumference, and levels of triglycerides and gamma-glutamyltransferase. There was a pattern of decreasing muscle density across increasing quartiles of FLI. After adjusting for age and lifestyle, mean radial muscle density in Q4 was 2.1% lower than Q1 (p < 0.001) and mean tibial muscle density was 1.8% lower in Q3 and 3.0% lower in Q4, compared to Q1 (p = 0.022 and < 0.001, respectively). After adjusting for age and sedentary lifestyle, participants in the highest FLI quartile were sixfold more likely to have sarcopenia. In conclusion, our results suggest that fat accumulation in the liver co-exists with fat infiltration into skeletal muscle.

Background and PurposeA high-altitude environment was known to have a negative effect on bone and lead to a higher incidence of hip fracture. However, the dependence of muscle composition on altitude is unclear. Thus, we aimed to compare muscle density and area in plateau and low altitude area and to determine the effect of the altitude on these outcomes.MethodsCommunity dwelling adults over 60 years old living in Beijing (elevation 50 m; 300 subjects,107 men and 193 women) or Kunming (elevation 2000 m; 218 subjects,83 men and 135 women) for more than 10 years were enrolled. Quantitative CT was performed in all subjects and cross-sectional area and attenuation measured in Hounsfield units (HU) were determined for the trunk, gluteus, and mid-thigh muscles.ResultsCompared to Beijing, Kunming adults were slimmer (Beijing men vs Kunming men: 25.08 ± 2.62 vs 23.94 ± 3.10kg/m2, P=0.013; Beijing women vs Kunming women: 25.31 ± 3.1 vs 23.98 ± 3.54 kg/m2, P= 0.001) and had higher muscle density in the L2-trunk and gluteus maximus muscles after adjustment for age and BMI (L2-trunk muscles: Beijing men 29.99 ± 4.17 HU vs Kunming men 37.35 ± 4.25 HU, P&lt; 0.0001; Beijing women 27.37 ± 3.76 HU vs Kunming women 31.51 ± 5.12 HU, P&lt; 0.0001; Gluteus maximus muscle: Beijing men 35.11 ± 6.54 HU vs Kunming men 39.36 ± 4.39 HU, P= 0.0009; Beijing women 31.47 ± 6.26 HU vs Kunming women 34.20 ± 5.87 HU P=0.0375). Age was similar in both cohorts and no differences were observed in the gluteus medius and minimus muscle or the mid-thigh muscle, either in the area or density.ConclusionsCompared with Beijing, the adults in Kunming had higher muscle density of the gluteus maximus and L2 trunk muscles, showing that living at a higher altitude might be beneficial to muscle quality.

Background Aging is associated with central fat redistribution and skeletal muscle decline, yet the relationships of tissue compartments with heart failure (HF) remain incompletely characterized. We assessed the contribution of body composition to incident HF in elders. Methods and Results Participants from 2 older cohorts who completed dual‐energy X‐ray absorptiometry (DEXA) and, in one cohort, computed tomography were included. We evaluated associations with incident HF for DEXA principal components (PCs) and total lean, appendicular lean, total fat and trunk fat mass; and for computed tomography measures of abdominal visceral and subcutaneous fat, thigh muscle, intermuscular fat area and thigh muscle density. DEXA analysis included 3621, and computed tomography analysis 2332 participants. During median follow‐up of 11.8 years, 927 participants developed HF. DEXA principal components showed no relationship with HF. After adjustment for height, weight, and cardiovascular risk factors, total lean mass was near significantly associated with higher HF (hazard ratio [HR], 1.25 per SD [1.00–1.56]), whereas total fat mass and thigh muscle density were significantly related to lower HF (HR, 0.82 [0.68–0.99] and HR, 0.87 [0.78–0.97], respectively). Patterns were similar for HF subtypes. The relationships with HF for total lean and fat mass were attenuated after adjusting for intercurrent atrial fibrillation or excluding high natriuretic peptide levels. Conclusions Total lean mass was positively associated, while total fat mass and thigh muscle density were inversely associated, with incident HF. These findings highlight the limitations of DEXA for assessment of HF risk in elders and support the preeminence of computed tomography–measured skeletal muscle quality over mass as a determinant of HF incidence.

HIGHLIGHT1. Pain intensity, smooth muscle cells density, and alpha-SMA expression can be used to analyze the role of smooth muscle in endometriosis.2. Compared to healthy individuals, those with endometriosis have higher pain intensity, smooth muscle cells density, and alpha-SMA expression. 3. Among endometriotic patients, those with peritoneal endometriosis have higher pain intensity, smooth muscle cells density, and alpha-SMA expression than those with ovarial endometriosis.3. The expression of alpha-SMA, smooth muscle density, and pain intensity were found to correlate significantly in endometriosis. ABSTRACTObjectives: to identify the role of smooth muscle through the analysis of smooth muscle cells density, expression of a-SMA, and the pain intensity.Materials and Methods: Study design is a cross sectional analytic observational. Study sample consists of women with ovarial endometrios and women with peritoneal endometriosis that undergo laparoscopy and laparotomy in RSUD Saiful Anwar Malang and RSIA Melati Malang from January until December 2019. There are 16 samples: 8 samples of ovarial endometriosis and 8 samples of peritoneal endometriosis. Smooth muscle cell density was analyzed by comparing the number of smooth muscle cells with the total area of endometriosis tissue in one microscopical field. a-SMA expression obtained by immunohistochemistry. Degree of pain obatined by filling the part 1 point 1-11 of EHP-30 queistionnaire the day after the procedure. Data was analyzed by Independent T-test and Pearson correlation.Results: Pain intensity, smooth muscle cells density, and a-SMA expression is higher in the endometriosis patient compared to healthy individual. Pain intensity, smooth muscle cells density, and a-SMA expression is lower in the ovarial endometriosis compared to peritoneal endometriosis.Conclusion: There are a significant correlation between the expression of a-SMA, smooth muscle density, and pain intensity in endometriosis.

Abstract Background Muscle mass declines with age, while body adiposity increases. Sarcopenic obesity has been proposed to be particularly deleterious. However, previous methods for estimating muscle mass have been inadequate, and the relative contributions of total body fat vs. muscle fat to adverse outcomes have been unclear. Methods In a large cohort of older men (N= 1017), we measured muscle mass (D3 creatine dilution), muscle density (high resolution peripheral computed tomography in the diaphyseal tibia) as a proxy of muscle fat, and total body fat (dual energy x-ray absorptiometry). We examined their associations with physical performance (walking speed, grip strength, chair stand time), the risk of mobility outcomes (mobility limitations, mobility disability), and the risk of death over ~5 years. Results In combined models, lower muscle mass and muscle density were independently associated with worse physical performance and the risk of adverse outcomes, while total body fat was minimally related to physical performance and not related to mobility outcomes or mortality. For example, the relative risks for mortality per 1 standardized unit increase in muscle density, muscle mass, and total body fat were 0.84 (95% CI: 0.74, 0.70), 0.70 (0.57, 0.86), and 0.90 (0.64, 1.25), respectively. Conclusions Muscle mass and muscle density were associated with physical performance and adverse outcomes, and had independent, additive effects. There was little additional contribution of total body fat.