Intermuscular Adipose Tissue: A Brief Review of Etiology, Association With Physical Function and Weight Loss in Older Adults

Association between sarcopenic obesity and risk of frailty in older adults: a systematic review and meta-analysis

BACKGROUND

Age-related changes in body composition such as muscle loss can lead to sarcopenia, which is closely associated with frailty. However, the effect of body fat accumulation on frailty in old age remains unclear. In particular, the association between the combination of these two conditions, known as sarcopenic obesity, and frailty in older adults is unclear.

OBJECTIVE

To synthesise the association between sarcopenic obesity and the risk of frailty and to investigate the role of obesity in the risk of frailty in old age.

METHODS

Six databases were searched from inception to 29 September 2024. Two reviewers independently extracted the data and assessed the risk of bias for the included observational studies using the adapted Newcastle-Ottawa scale. The control groups consisted of robust, obese and sarcopenic individuals. Meta-analyses were performed to examine the risk of frailty due to sarcopenic obesity and the role of obesity in frailty amongst sarcopenic older adults.

RESULTS

Sixteen eligible studies were included in meta-analyses from 1098 records. Compared to robust individuals, older adults with sarcopenic obesity were more vulnerable to frailty [odds ratio (OR), 3.76; 95% confidence interval (CI), 2.62 to 5.39; I2 = 79.3%; P < .0001]. Obesity was not associated with the risk of frailty (OR, 1.23; 95% CI, 0.99 to 1.53; I2 = 0.0%; P = .501) in sarcopenic older adults.

CONCLUSIONS

Sarcopenic obesity is associated with a high risk of frailty. Sarcopenia and obesity may have synergistic effects on frailty in older adults.

A validated estimate of visceral adipose tissue volume in relation to cancer risk

BACKGROUND

Despite the recognized role of visceral adipose tissue in carcinogenesis, its independent association with cancer risk beyond traditional obesity measures remains unknown because of limited availability of imaging data.

METHODS

We developed an estimation equation for visceral adipose tissue volume using elastic net regression based on demographic and anthropometric data in a subcohort of participants in the UK Biobank (UKB; n = 23 148) with abdominal magnetic resonance imaging scans. This equation was externally validated in 2713 participants from the 2017-2018 National Health and Nutrition Examination Survey according to sex, age, and race groups. We then applied the equation to the overall UKB cohort of 461 665 participants to evaluate the prospective association between estimated visceral adipose tissue and cancer risk using Cox proportional hazards models. We also calculated the population attributable risk of cancer associated with estimated visceral adipose tissue and body mass index (BMI).

RESULTS

Estimated visceral adipose tissue showed a high correlation with measured visceral adipose tissue in internal and external validations (r = 0.81-0.86). During a median 12-year follow-up in the UKB, we documented 37 397 incident cancer cases; estimated visceral adipose tissue was statistically significantly associated with elevated risk of obesity-related and individual cancers, independent of BMI and waist circumference. Population attributable risk for total cancer associated with high (quartiles 2-4 vs 1) estimated visceral adipose tissue (9.0% for men, 11.6% for women) was higher than high BMI (quartiles 2-4 vs 1 = 5.0% for men, 8.2% for women).

CONCLUSIONS

Estimated visceral adipose tissue showed robust performance in UKB and National Health and Nutrition Examination Survey and was associated with cancer risk independent of BMI and waist circumference. This study provides a potential clinical tool for visceral adipose tissue estimation and underscores that visceral adipose tissue can be an important target for cancer prevention.

A retrospective evaluation of individual thigh muscle volume disparities based on hip fracture types in followed-up patients: an AI-based segmentation approach using UNETR

Background

Hip fractures are a common and debilitating condition, particularly among older adults. Loss of muscle mass and strength is a common consequence of hip fractures, which further contribute to functional decline and increased disability. Assessing changes in individual thigh muscles volume in follow-up patients can provide valuable insights into the quantitative recovery process and guide rehabilitation interventions. However, accurately measuring anatomical individual thigh muscle volume can be challenging due to various, labor intensive and time-consuming.

Materials and Methods

This study aimed to evaluate differences in thigh muscle volume in followed-up hip fracture patients computed tomography (CT) scans using an AI based automatic muscle segmentation model. The study included a total of 18 patients at Gyeongsang National University, who had undergone surgical treatment for a hip fracture. We utilized the automatic segmentation algorithm which we have already developed using UNETR (U-net Transformer) architecture, performance dice score = 0.84, relative absolute volume difference 0.019 ± 0.017%.

Results

The results revealed intertrochanteric fractures result in more significant muscle volume loss (females: -97.4 cm3, males: -178.2 cm3) compared to femoral neck fractures (females: -83 cm3, males: -147.2 cm3). Additionally, the study uncovered substantial disparities in the susceptibility to volume loss among specific thigh muscles, including the Vastus lateralis, Adductor longus and brevis, and Gluteus maximus, particularly in cases of intertrochanteric fractures.

Conclusions

The use of an automatic muscle segmentation model based on deep learning algorithms enables efficient and accurate analysis of thigh muscle volume differences in followed up hip fracture patients. Our findings emphasize the significant muscle loss tied to sarcopenia, a critical condition among the elderly. Intertrochanteric fractures resulted in greater muscle volume deformities, especially in key muscle groups, across both genders. Notably, while most muscles exhibited volume reduction following hip fractures, the sartorius, vastus and gluteus groups demonstrated more significant disparities in individuals who sustained intertrochanteric fractures. This non-invasive approach provides valuable insights into the extent of muscle atrophy following hip fracture and can inform targeted rehabilitation interventions.

Nutritional Mechanisms of Cancer Cachexia

Cancer cachexia is a complex systemic wasting syndrome. Nutritional mechanisms that span energy intake, nutrient metabolism, body composition, and energy balance may be impacted by, and may contribute to, the development of cachexia. To date, clinical management of cachexia remains elusive. Leaning on discoveries and novel methodologies from other fields of research may bolster new breakthroughs that improve nutritional management and clinical outcomes. Characteristics that compare and contrast cachexia and obesity may reveal opportunities for cachexia research to adopt methodology from the well-established field of obesity research. This review outlines the known nutritional mechanisms and gaps in the knowledge surrounding cancer cachexia. In parallel, we present how obesity may be a different side of the same coin and how obesity research has tackled similar research questions. We present insights into how cachexia research may utilize nutritional methodology to expand our understanding of cachexia to improve definitions and clinical care in future directions for the field.

Causal association of circulating cytokines with sarcopenia-related traits: A Mendelian randomization study

BACKGROUND

Observational studies have reported that circulating cytokines are associated with sarcopenia. However, the causal relationship between circulating cytokines and sarcopenia has not been elucidated.

OBJECTIVES

This study aimed to investigate the causal relationship between circulating cytokines and sarcopenia with genetic data using Mendelian randomization (MR).

METHODS

Two-sample bidirectional MR analysis was performed to investigate the causal relationship in individuals of European ancestry. The publicly available genome-wide association study statistics were used to select the key eligible single nucleotide polymorphisms significantly associated with circulating cytokines. Multiple MR analysis approaches, including inverse variance weighted (IVW), MR-Egger, weighted median method (WMM), and MR-Pleiotropy residual Sum and Outlier (MR-PRESSO) methods, were used for the analysis. Sarcopenia-related traits were appendicular lean mass (ALM) and grip strength.

RESULTS

This study demonstrated the causal effect of genetically predicted circulating interleukin interleukin-16 (IL16) levels on both ALM [odds ratio (OR) = 0.990, 95% confidence interval (CI): 0.980-1.000, P = 0.049] and grip strength (OR = 0.971, 95% CI: 0.948-0.995, P = 0.020]. Additionally, C-X-C motif chemokine ligand 10 (CXCL10), interleukin-1beta (IL1B), and hepatocyte growth factor (HGF) were correlated with ALM, while vascular endothelial growth factor (VEGF), interleukin-12 (IL12), and interleukin-15 (IL15) were correlated with grip strength. The results of MR-Egger, weighted median, weighted mode, and simple mode methods were consistent with the IVW estimates. Sensitivity analysis revealed that horizontal pleiotropy did not bias the causal estimates.

CONCLUSION

These findings indicate that inflammatory cytokines exert a significant causal effect on sarcopenia and provide promising leads for the development of novel therapeutic targets for the disease. By evaluating the role of circulating cytokines in the pathologic condition via a genetic epidemiological approach, our study made contributions to a further investigation of underlying mechanisms of sarcopenia.

Non invasive techniques for direct muscle quality assessment after exercise intervention in older adults: a systematic review

BACKGROUND

The aging process induces neural and morphological changes in the human musculoskeletal system, leading to a decline in muscle mass, strength and quality. These alterations, coupled with shifts in muscle metabolism, underscore the essential role of physical exercise in maintaining and improving muscle quality in older adults. Muscle quality's morphological domain encompasses direct assessments of muscle microscopic and macroscopic aspects of muscle architecture and composition. Various tools exist to estimate muscle quality, each with specific technical requirements. However, due to the heterogeneity in both the studied population and study methodologies, there is a gap in the establishment of reference standards to determine which are the non-invasive and direct tools to assess muscle quality after exercise interventions. Therefore, the purpose of this review is to obtain an overview of the non-invasive tools used to measure muscle quality directly after exercise interventions in healthy older adults, as well as to assess the effects of exercise on muscle quality.

MAIN TEXT

To address the imperative of understanding and optimizing muscle quality in aging individuals, this review provides an overview of non-invasive tools employed to measure muscle quality directly after exercise interventions in healthy older adults, along with an assessment of the effects of exercise on muscle quality.

RESULTS

Thirty four studies were included. Several methods of direct muscle quality assessment were identified. Notably, 2 studies harnessed CT, 20 utilized US, 9 employed MRI, 2 opted for TMG, 2 adopted myotonometry, and 1 incorporated BIA, with several studies employing multiple tests. Exploring interventions, 26 studies focus on resistance exercise, 4 on aerobic training, and 5 on concurrent training.

CONCLUSIONS

There is significant diversity in the methods of direct assessment of muscle quality, mainly using ultrasound and magnetic resonance imaging; and a consistent positive trend in exercise interventions, indicating their efficacy in improving or preserving muscle quality. However, the lack of standardized assessment criteria poses a challenge given the diversity within the studied population and variations in methodologies.. These data emphasize the need to standardize assessment criteria and underscore the potential benefits of exercise interventions aimed at optimizing muscle quality.

Association between muscle quality and nutritional status among community-dwelling older adults: A cross-sectional study

Background: Decline in muscle quality is associated with poorer health in community-dwelling older adults. Although there is evidence that malnutrition is associated with the decline of muscle quality in older adults, few analyses have considered important factors related to muscle quality. Aim: The purpose of this study was to determine the relationship between muscle quality and nutritional status in community-dwelling older adults, taking into account muscle mass, muscle strength, and amount of physical activity. Methods: This was a cross-sectional study. Data were obtained from a health checkup program in Japan. Participants were older adults aged ≥65 years living in the community who participated in the health checkup program. The data collected were echo intensity, scores on the Global Leadership Initiative on Malnutrition criteria, skeletal muscle mass, grip strength, physical activity level, and demographic data. Multiple regression analysis was used to examine the association between muscle quality and nutritional status. Results: Data were analyzed for 50 participants (mean age 77.62 years, standard deviation 6.16 years, 78.0% women). Multiple regression analysis showed that nutritional status affected muscle quality even when various factors were taken into account (B = 6.95, β = 0.31, p = 0.04, 95% confidence interval: 0.01-0.62). Conclusion: The observed association suggests that providing nutritional support for older adults living in the community may be a useful strategy to maintain muscle quality.

Influence of sarcopenia on postoperative complications and long-term survival in pancreatic cancer patients undergone pancreaticoduodenectomy

Background

Sarcopenia has the potential to impact the postoperative results and extended prognosis of various types of tumors. Nevertheless, the specific impact of sarcopenia on the postoperative results and long-term survival of pancreatic cancer (PC) following pancreaticoduodenectomy (PD) remains inadequately elucidated. This study investigates the significance of sarcopenia according to various Asian standards on postoperative complications and long-term prognosis in PC patients who have undergone PD.

Methods

This retrospective study systematically analyzed patients with PC who underwent PD from January 2015 to December 2022. Sarcopenia was diagnosed by the skeletal muscle index (SMI) obtained by the skeletal muscle area normalized for height squared on the third lumbar vertebra on computed tomography (CT) images. Univariate and multivariate logistic regression analysis were performed to analyze the correlation between sarcopenia and postoperative complications, while Cox regression analysis was utilized to explore the influence of sarcopenia on overall survival (OS) and recurrence-free survival (RFS) in PC patients after PD.

Results

We enrolled 162 patients with PC after PD (92 males and 70 females, mean age: 63.78 ± 10.27 years), including 83 and 79 patients with sarcopenia and non-sarcopenia, respectively. Compared with non-sarcopenia patients, sarcopenia exhibited higher rates of recurrence rate (75% versus 59%, p = 0.039). Univariate and multivariate logistic regression analysis showed that sarcopenia did not affect the incidence of complications in patients with PC after PD in three Asian sarcopenia criteria. Multivariate Cox regression analysis indicated that sarcopenia was an independent risk factor for OS (hazard ratio [HR]: 2.49, 95% confidence interval [CI]: 1.73-3.60, p < 0.001) and RFS(hazard ratio [HR]: 1.70, 95%confidence interval [CI]: 1.12-2.50, p = 0.012) of PC patients with PD in Japanese Society of Hepatology criteria. Meanwhile, according to the Asian pancreatic cancer population standard, sarcopenia is an independent risk factor affecting the long-term OS (hazard ratio [HR]: 2.59, 95% confidence interval [CI]: 1.80-3.70, p < 0.001) and RFS (hazard ratio [HR]: 2.00, 95% confidence interval [CI]: 1.36-3.00, p < 0.001) of PC after PD. While sarcopenia is recognized as a risk factor for OS (hazard ratio [HR]: 1.81, 95% confidence interval [CI]: 1.08-3.10, p = 0.025) in PC patients based on the Fujiwara criteria, it is not found to be associated with RFS (hazard ratio [HR]: 1.60, 95% confidence interval [CI]: 0.90-3.00, p = 0.10). The model based on sarcopenia and clinical characteristics has high predictive ability for OS and RFS.

Conclusion

Various Asian diagnostic criteria do not link sarcopenia with postoperative complications in PC patients after PD. Nevertheless, sarcopenia remains a significant independent risk factor for long-term survival, and its combination with clinical characteristics can aid clinicians in predicting long-term survival outcomes.

Exploring the causal link between circulating cytokines and sarcopenia traits: A Mendelian randomization analysis

BACKGROUND

Previous observational studies have linked circulating cytokines to sarcopenia, but their causal relationship remains unclear. This study employed Mendelian Randomization (MR) to investigate the causal links between circulating cytokines and sarcopenia-related traits using genetic data.

METHODS

A two-sample bidirectional MR analysis was conducted using data from individuals of European ancestry, utilizing genome-wide association studies (GWAS) statistics. The study selected instrumental single nucleotide polymorphisms (SNPs) significantly associated with circulating cytokines and applied multiple MR methods, including inverse variance weighted (IVW), Weighted Median, MR-Egger, Weighted Mode, Simple Mode, and MR-PRESSO. The traits analyzed were appendicular lean mass (ALM) and grip strength. Heterogeneity, robustness, and consistency of results were assessed using Cochran's Q statistic, MR-Egger regression, and "leave-one-out" sensitivity analyses.

RESULTS

The IVM-MR analysis showed a casual association between genetically predicted circulating levels of interleukin-16 and both ALM and grip strength (ALM: OR = 0.990, 95% CI: 0.980-1.000, p = .049; grip strength: OR = 0.971, 95% CI: 0.948-0.995, p = .020). Additionally, interferon-gamma-induced protein 10 (IP-10), interleukin-1-beta (IL-1β), and hepatocyte growth factor (HGF) were correlated with ALM and vascular endothelial growth factor (VEGF), interleukin-12 (IL-12), and interleukin-5 (IL-5) with grip strength. Comparable results were confirmed via the MR-Egger, Weighted Median, Weighted Mode, and Simple Mode methods. Sensitivity analysis showed no horizontal pleiotropy to bias the causal estimates.

CONCLUSION

The results suggest a significant causal effect of inflammatory cytokines on sarcopenia, offering new avenues for therapeutic target development. However, the study's focus on a European ancestry cohort limits its generalizability to other populations. Future research should aim to include diverse ethnic groups to validate and broaden these findings, thereby enhancing our understanding of sarcopenia's mechanisms in a global context.

The effects of myosteatosis on skeletal muscle function in older adults

Myosteatosis, or the infiltration of fatty deposits into skeletal muscle, occurs with advancing age and contributes to the health and functional decline of older adults. Myosteatosis and its inflammatory milieu play a larger role in adipose tissue dysfunction, muscle tissue dysfunction, and increased passive muscle stiffness. Combined with the age-related decline of sex hormones and development of anabolic resistance, myosteatosis also contributes to insulin resistance, impaired muscle mechanics, loss of force production from the muscle, and increased risk of chronic disease. Due to its highly inflammatory secretome and the downstream negative effects on muscle metabolism and mechanics, myosteatosis has become an area of interest for aging researchers and clinicians. Thus far, myosteatosis treatments have had limited success, as many lack the potency to completely rescue the metabolic and physical consequences of myosteatosis. Future research is encouraged for the development of reliable assessment methods for myosteatosis, as well as the continued exploration of pharmacological, nutritional, and exercise-related interventions that may lead to the success in attenuating myosteatosis and its clinical consequences within the aging population.

Influence of skeletal muscle and intermuscular fat on postoperative complications and long-term survival in rectal cancer patients

BACKGROUND

The body composition of patients with rectal cancer potentially affects postoperative outcomes. This study explored the correlations between skeletal muscle and adipose tissue quantified by computed tomography (CT) with postoperative complications and long-term prognosis in patients with rectal cancer after surgical resection.

METHODS

This retrospective cohort study included patients with rectal cancer who underwent surgical resection at the Wuhan Union Hospital between 2014 and 2018. CT images within 3 months prior to the surgery were used to quantify the indices of skeletal muscle and adipose tissue at the levels of the third lumbar vertebra (L3) and umbilicus. Optimal cut-off values for each index were defined separately for males and females. Associations between body composition and postoperative complications, overall survival (OS), and disease-free survival (DFS) were evaluated using logistic and Cox proportional hazards models.

RESULTS

We included 415 patients (240 males and 175 females; mean age: 57.8 ± 10.5 years). At the L3 level, a high skeletal muscle density (SMD; hazard ratio [HR]: 0.357, 95% confidence interval [CI]: 0.191-0.665, P = 0.001; HR: 0.571, 95% CI: 0.329-0.993, P = 0.047) and a high skeletal muscle index (SMI; HR: 0.435, 95% CI 0.254-0.747, P = 0.003; HR: 0.568, 95% CI: 0.359-0.897, P = 0.015) were independent prognostic factors for better OS and DFS. At the umbilical level, a large intermuscular fat area (IMFA; HR: 1.904, 95% CI: 1.068-3.395, P = 0.029; HR: 2.064, 95% CI: 1.299-3.280, P = 0.002) was an independent predictive factor for worse OS and DFS, and a high SMI (HR: 0.261, 95% CI: 0.132-0.517, P < 0.001; HR: 0.595, 95% CI: 0.387-0.913, P = 0.018) was an independent prognostic factor for better OS and DFS. The models combining body composition and clinical indicators had good predictive abilities for OS. The receiver operating characteristic areas under the curve were 0.848 and 0.860 at the L3 and umbilical levels, respectively (both P < 0.05).

CONCLUSIONS

No correlations existed between CT-quantified body composition parameters and postoperative complications. However, a high SMD and high SMI were significantly associated with longer OS and DFS at the L3 level, whereas a large IMFA and low SMI were associated with worse OS and DFS at the umbilical level. Combining CT-quantified body composition and clinical indicators could help physicians predict the prognosis of patients with rectal cancer after surgery.

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.

Aging adipose tissue, insulin resistance, and type 2 diabetes

With the increase of population aging, the prevalence of type 2 diabetes (T2D) is also rising. Aging affects the tissues and organs of the whole body, which is the result of various physiological and pathological processes. Adipose tissue has a high degree of plasticity and changes with aging. Aging changes the distribution of adipose tissue, affects adipogenesis, browning characteristics, inflammatory status and adipokine secretion, and increases lipotoxicity. These age-dependent changes in adipose tissue are an important cause of insulin resistance and T2D. Understanding adipose tissue changes can help promote healthy aging process. This review summarizes changes in adipose tissue ascribable to aging, with a focus on the role of aging adipose tissue in insulin resistance and T2D.

Sex Differences in the Association of Weight-Adjusted-Waist Index with Sarcopenic Obesity: A Cross-Sectional Study of Hemodialysis Patients

Objective: To explore the association between weight-adjusted-waist index (WWI) and sarcopenic obesity (SO) in patients with maintenance hemodialysis (MHD). Methods: A multicenter, cross-sectional study that included 3311 adult MHD patients was conducted in 20 hemodialysis (HD) centers from June 1, 2021, to August 30, 2021. Body composition was evaluated by body composition monitor based on bioimpedance spectroscopy. Hand grip strength was measured by CAMRY® dynamometer. WWI was calculated as waist circumference (cm) divided by the square root of body weight (kg). Multiple logistic regression models, spearman correlation analysis, and receiver-operating characteristic (ROC) analyses were conducted. Results: The median age of the study was 55 years, and 39.4% of patients were female. The prevalence of SO was 22.7% in the total population, and patients with SO had higher WWI. Higher WWI quartiles were independently associated with a higher risk of SO in men after adjusting for potential confounders, including age, dialysis vintage, body mass index, biochemical indicators, and various medical histories; the odds ratio (OR) of SO was highest in the fourth quartile of the WWI (OR: 4.08, 95% confidence interval: 2.65-6.27, P for trend <0.001). Age-adjusted WWI provided a better diagnostic power than WWI only for SO in men (area under the ROC curve: 0.72 vs. 0.68, P < 0.001). WWI was not associated with SO in female HD patients. Conclusion: WWI is independently associated with SO in male but not female MHD patients. This anthropometric index is simple to calculate, making it applicable in clinical practice.

Gastric inhibitory polypeptide receptor antagonism suppresses intramuscular adipose tissue accumulation and ameliorates sarcopenia

BACKGROUND

Intramuscular adipose tissue (IMAT) formation derived from muscle fibro-adipogenic progenitors (FAPs) has been recognized as a pathological feature of sarcopenia. This study aimed to explore whether genetic and pharmacological gastric inhibitory polypeptide (GIP) receptor antagonism suppresses IMAT accumulation and ameliorates sarcopenia in mice.

METHODS

Whole body composition, grip strength, skeletal muscle weight, tibialis anterior (TA) muscle fibre cross-sectional area (CSA) and TA muscle IMAT area were measured in young and aged male C57BL/6 strain GIP receptor (Gipr)-knockout (Gipr-/- ) and wild-type (Gipr+/+ ) mice. FAPs isolated from lower limb muscles of 12-week-old Gipr+/+ mice were cultured with GIP, and their differentiation into mature adipocytes was examined. Furthermore, TA muscle IMAT area and fibre CSA were measured in untreated Gipr-/- mice and GIP receptor antagonist-treated Gipr+/+ mice after glycerol injection into the TA muscles.

RESULTS

Body composition analysis revealed that 104-week-old Gipr-/- mice had a greater proportion of lean tissue mass (73.7 ± 1.2% vs. 66.5 ± 2.7%, P < 0.05 vs. 104-week-old Gipr+/+ mice) and less adipose tissue mass (13.1 ± 1.3% vs. 19.4 ± 2.6%, P < 0.05 vs. 104-week-old Gipr+/+ mice). Eighty-four-week-old Gipr-/- mice exhibited increases in grip strength (P < 0.05), weights of TA (P < 0.05), soleus (P < 0.01), gastrocnemius (P < 0.05) and quadriceps femoris (P < 0.01) muscles, and average TA muscle fibre CSA (P < 0.05) along with a reduction in TA muscle IMAT area assessed by the number of perilipin-positive cells (P < 0.0001) compared with 84-week-old Gipr+/+ mice. Oil Red O staining analysis revealed 1.6- and 1.7-fold increased adipogenesis in muscle FAPs cultured with 10 and 100 nM of GIP (P < 0.01 and P < 0.001 vs. 0 nM of GIP, respectively). Furthermore, both untreated Gipr-/- mice and GIP receptor antagonist-treated Gipr+/+ mice for 14 days after glycerol injection into the TA muscles at 12 weeks of age showed reduced TA muscle IMAT area (1.39 ± 0.38% and 2.65 ± 0.36% vs. 6.54 ± 1.30%, P < 0.001 and P < 0.01 vs. untreated Gipr+/+ mice, respectively) and increased average TA muscle fibre CSA (P < 0.01 and P < 0.05 vs. untreated Gipr+/+ mice, respectively).

CONCLUSIONS

GIP promotes the differentiation of muscle FAPs into adipocytes and its receptor antagonism suppresses IMAT accumulation and promotes muscle regeneration. Pharmacological GIP receptor antagonism may serve as a novel therapeutic approach for sarcopenia.

Decreased intracellular water is associated with sarcopenic obesity in chronic haemodialysis patients

OBJECTIVE

To explore the association between intracellular water (ICW) and sarcopenic obesity in patients undergoing chronic haemodialysis (HD).

METHODS

A multicentre, cross-sectional study of 3354 adult chronic HD patients was conducted in 20 haemodialysis centres from June 1, 2021, to August 30, 2021. The diagnosis of sarcopenic obesity was made according to the revised Asian Working Group's definition of sarcopenia combined with obesity per the body fat percentage definition. Body composition was evaluated by a body composition monitor using bioimpedance spectroscopy. Multiple logistic regression models, stratified analyses, interactive analyses, and receiver-operating characteristic analyses were conducted.

RESULTS

A total of 752 patients were diagnosed with sarcopenic obesity among 3354 participants. The patients were grouped by sex-specific ICW median levels, and the prevalence of sarcopenic obesity was significantly higher in the low ICW group than in the high ICW group (41.3%vs 3.0%). Decreased ICW was significantly associated with sarcopenic obesity. The association remained statistically significant even after adjusting for dialysis vintage, age, body mass index, biochemical indicators, and various medical histories. The odds ratios of the low ICW group were much higher than those of the high ICW group in both males and females (P for trend < 0.001). The association was stable across subgroups, and the interaction analysis showed that age, body mass index and history of diabetes had interactive roles in the association between ICW and sarcopenic obesity (P for interaction < 0.05). Furthermore, the ICW cut-off values for identifying sarcopenic obesity were 19.1 kg and 14.5 kg for males and females, respectively.

CONCLUSION

Decreased ICW was an independent risk factor for sarcopenic obesity in chronic HD patients. The measurement of ICW by bioimpedance spectroscopy might be a non-invasive and valid means for identifying the risk of future sarcopenic obesity in HD patients.

Muscle quality and not quantity as a predictor of survival in head and neck squamous cell carcinoma

BACKGROUND

Sarcopenia is frequent in head and neck squamous cell carcinoma (HNSCC), as a consequence of malnutrition related to risk factors or tumoral mass. Treatment is associated with toxicities that lead to reduced calories intake and muscle mass wasting. Sarcopenia has been negatively associated with tumor control and survival outcomes.

PURPOSE

Our aim is to evaluate the prognostic impact of sarcopenia on overall survival (OS) and progression free survival (PFS) in HNSCC patients undergoing chemoradiation therapy within a prospective clinical trial of chemoradiation vs induction chemotherapy followed by radiation and cetuximab (INTERCEPTOR).

MATERIALS AND METHODS

On baseline CT or MRI, we investigated the association between OS and PFS with radiological markers of sarcopenia, measured at the third cervical vertebra level. We studied paravertebral skeletal muscles area (cm2), muscle density (HU), muscle index (cm2/m2), and intermuscular adipose tissue (IMAT) area (cm2).

RESULTS

Imaging of 128 patients was evaluable. We found out that higher body mass index (BMI) was associated with better OS (p = 0.02), and PFS (p = 0.04). Skeletal muscle area (p = 0.02), and IMAT (p = 0.02) were negatively associated with PFS. IMAT was positively correlated with muscle area (Correlation coefficient 0.6, CI95% 0.47-0.7), and negatively associated with muscle density (Correlation coefficient -0.37, CI95% -0.53 - -0.18).

CONCLUSIONS

IMAT can be used as predictor of PFS in HNC patients undergoing chemoradiation therapy. The amount of intermuscular fat deposits induces alterations of muscle quality, without alterations of muscle quantity, influencing patients' prognosis.

Exercise-induced modulation of Interferon-signature: a therapeutic route toward management of Systemic Lupus Erythematosus

Systemic Lupus Erythematosus (SLE) is a multisystemic autoimmune disorder characterized by flares-ups/remissions with a complex clinical picture related to disease severity and organ/tissue injury, which, if left untreated, may result in permanent damage. Enhanced fatigue and pain perception, worsened quality of life (QoL) and outcome are constant, albeit symptoms may differ. An aberrant SLE immunoprofiling, note as "interferon (IFN)α-signature", is acknowledged to break immunotolerance. Recently, a deregulated "IFNγ-signature" is suggested to silently precede/trigger IFNα profile before clinical manifestations. IFNα- and IFNγ-over-signaling merge in cytokine/chemokine overexpression exacerbating autoimmunity. Remission achievement and QoL improvement are the main goals. The current therapy (i.e., corticosteroids, immunosuppressants) aims to downregulate immune over-response. Exercise could be a safe treatment due to its ever-emerging ability to shape and re-balance immune system without harmful side-effects; in addition, it improves cardiorespiratory capacity and musculoskeletal strength/power, usually impaired in SLE. Nevertheless, exercise is not yet included in SLE care plans. Furthermore, due to the fear to worsening pain/fatigue, SLE subjects experience kinesiophobia and sedentary lifestyle, worsening physical health. Training SLE patients to exercise is mandatory to fight inactive behavior and ameliorate health. This review aims to focus the attention on the role of exercise as a non-pharmacological therapy in SLE, considering its ability to mitigate IFN-signature and rebalance (auto)immune response. To this purpose, the significance of IFNα- and IFNγ-signaling in SLE etiopathogenesis will be addressed first and discussed thereafter as biotarget of exercise. Comments are addressed on the need to make aware all SLE care professional figures to promote exercise for health patients.

VEGFA Promotes Skeletal Muscle Regeneration in Aging

Aging is associated with loss of skeletal muscle regeneration. Differentially regulated vascular endothelial growth factor (VEGF)A with aging may partially underlies this loss of regenerative capacity. To assess the role of VEGFA in muscle regeneration, young (12-14 weeks old) and old C57BL/6 mice (24,25 months old) are subjected to cryoinjury in the tibialis anterior (TA) muscle to induce muscle regeneration. The average cross-sectional area (CSA) of regenerating myofibers is 33% smaller in old as compared to young (p < 0.01) mice, which correlates with a two-fold loss of muscle VEGFA protein levels (p = 0.02). The capillary density in the TA is similar between the two groups. Young VEGFlo mice, with a 50% decrease in systemic VEGFA activity, exhibit a two-fold reduction in the average regenerating fiber CSA following cryoinjury (p < 0.01) in comparison to littermate controls. ML228, a hypoxia signaling activator known to increase VEGFA levels, augments muscle VEGFA levels and increases average CSA of regenerating fibers in both old mice (25% increase, p < 0.01) and VEGFlo (20% increase, p < 0.01) mice, but not in young or littermate controls. These results suggest that VEGFA may be a therapeutic target in age-related muscle loss.

Skeletal muscle mass in patients with end-stage liver disease: Not only muscle size but especially muscle quality matters in relation to physical fitness

BACKGROUND

Physical fitness is an important modifiable factor related to quality of life. Sarcopenia and myosteatosis are associated with morbidity and mortality in patients with end-stage liver disease (ESLD). However, their relationship with physical fitness has not been established yet. Therefore, the main purpose of this study was to investigate the association between both low skeletal muscle index (SMI) and myosteatosis with physical fitness in patients with ESLD.

METHODS

In this retrospective cross-sectional cohort study, a cohort of patients with ESLD who were evaluated for liver transplantation (LT) was included. Physical fitness was reflected by cardiorespiratory fitness (CRF) and skeletal muscle strength, as measured by the 6-min walking distance (6MWD) and handgrip strength (HGS), respectively. Both were included in routine LT evaluation. Skeletal Muscle Index (SMI) and Muscle Radiation Attenuation (MRA) were evaluated based on the routine abdominal computed tomography. Linear and logistic regression analyses were performed.

RESULTS

Out of the 130 patients 94 (72%) were male, mean age was 56 ± 11 years. Myosteatosis was significantly associated with low 6MWD as percentage of predicted (β = -12.815 (CI -24.608 to -1.022, p-value 0.034)) as well as with low absolute 6MWD (<250 m) (OR 3.405 (CI 1.134-10.220, p-value 0.029)). No association was found between SMI and/or myosteatosis with HGS, or between SMI and 6MWD.

CONCLUSION

In contrast to SMI, myosteatosis is associated with low CRF. Neither low SMI nor myosteatosis was associated with skeletal muscle strength. Therefore physical exercise training might be especially beneficial for LT candidates with myosteatosis.

Macrophage Involvement in Aging-Associated Skeletal Muscle Regeneration

The skeletal muscle is a dynamic organ composed of contractile muscle fibers, connective tissues, blood vessels and nerve endings. Its main function is to provide motility to the body, but it is also deeply involved in systemic metabolism and thermoregulation. The skeletal muscle frequently encounters microinjury or trauma, which is primarily repaired by the coordinated actions of muscle stem cells (satellite cells, SCs), fibro-adipogenic progenitors (FAPs), and multiple immune cells, particularly macrophages. During aging, however, the capacity of skeletal muscle to repair and regenerate declines, likely contributing to sarcopenia, an age-related condition defined as loss of muscle mass and function. Recent studies have shown that resident macrophages in skeletal muscle are highly heterogeneous, and their phenotypes shift during aging, which may exacerbate skeletal muscle deterioration and inefficient regeneration. In this review, we highlight recent insight into the heterogeneity and functional roles of macrophages in skeletal muscle regeneration, particularly as it declines with aging.

Visceral to subcutaneous fat ratio predicts short-term mortality in patients with Covid 19. A multicenter study

OBJECTIVE

To evaluate the association of body composition parameters with outcomes in Covid-19.

METHODS

173 patients hospitalized for Covid-19 infection in 6 European centers were included in this retrospective study. Measurements were performed at L3-level and comprised skeletal muscle index (SMI), muscle density (MD), and adipose tissue measurements [visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), intramuscular adipose tissue (IMAT), visceral-to-subcutaneous-adipose-tissue-area-ratio (VSR)]. The association with mortality, the need for intubation (MV), and the need for admission to ICU within 30 days were evaluated.

RESULTS

Higher SAT density was associated with a greater risk of MV (OR = 1.071, 95%CI=(1.034;1.110), p < 0.001). Higher VAT density was associated with admission to ICU (OR = 1.068, 95%CI=(1.029;1.109), p < 0.001). Higher MD was a protective factor for MV and ICU admission (OR = 0.914, 95%CI=(0.870;0.960), p < 0.001; OR = 0.882, 95%CI=(0.832;0.934), p = 0.028). Higher VSR was associated with mortality (OR = 2.147, 95%CI=(1.022;4.512), p = 0.044). Male sex showed the strongest influence on the risk of ICU admission and MV. SMI was not associated with either parameter.

CONCLUSION

In patients hospitalized for Covid-19 infection, higher VSR seems to be a strong prognostic factor of short-term mortality. Weak associations with clinical course were found for MD and adipose tissue measurements. Male sex was the strongest prognostic factor of adverse clinical course.

ADVANCES IN KNOWLEDGE

VSR is a prognostic biomarker for 30-day mortality in patients hospitalized for Covid-19 disease.

Associations of Trunk Muscle Mass and Muscle Quality Indicators with Self-Reported Dysphagia in Older Inpatients

Recent studies have correlated dysphagia with ultrasound-measured quadriceps muscle mass and quality. Computed tomography (CT) is more precise than ultrasound for estimating muscle mass and quality. We aimed to investigate the possible associations of chest CT-determined trunk muscle mass and quality with dysphagia. A cross-sectional study. Older inpatients in a geriatric department of a university hospital. Self-reported dysphagia was determined by the Dysphagia Handicap Index. Unenhanced chest CT images were segmented to calculate skeletal muscle area (SMA) and intermuscular adipose tissue (IMAT). Skeletal muscle index (SMI) was calculated via SMA/ height squared. The percentage of IMAT (IMAT%) was calculated by IMAT% = IMAT/ (SMA + IMAT) × 100%. Mimics software was applied to calculate the mean skeletal muscle radio density (SMD).The semiquantitative food frequency method, the Barthel Index (BI), and the Mini Nutritional Assessment Short-Form (MNA-SF) were used to evaluate energy intake, activities of daily living, and nutrition status, respectively. Among the 212 participants (mean age: 84 years), 89 (42%) had self-reported dysphagia. After adjustment for age, nutrition status, energy intake, and other confounders, the SMI (adjusted OR 0.91, 95% CI 0.86, 0.96) was negatively associated with dysphagia, whereas the IMAT (adjusted OR 1.08, 95% CI 1.01, 1.16) and the IMAT% (adjusted OR 1.10, 95% CI 1.04,1.17) were positively associated with dysphagia. However, the SMD (adjusted OR 0.99, 95% CI 0.94, 1.05) was not significantly associated with dysphagia. The subgroup analyses indicated that only the SMI (adjusted OR 0.92, 95% CI 0.86, 0.97) and the IMAT% (adjusted OR 1.08, 95% CI 1.01, 1.17) were significantly associated with dysphagia in men. None of these indicators was significantly associated with dysphagia in women. Trunk muscle mass and quality (estimated by chest CT-derived SMI and IMAT%, respectively) were significantly associated with self-reported dysphagia in older inpatients, especially in men. IMAT% might be a more sensitive muscle quality indicator than IMAT (or SMD). These results merit further investigation in prospective studies.

Association between physical activity, growth differentiation factor 15 and bodyweight in older adults: A longitudinal mediation analysis

BACKGROUND

Late-life aging is often associated with appetite reduction and weight loss. Physical activity (PA) may prevent these processes, but the molecular mechanisms involved remain elusive. The present study investigated the putative mediating aspect of growth differentiation factor 15 (GDF-15), a stress signalling protein involved in aging, exercise and appetite control, on the association between PA and late-life-associated weight loss.

METHODS

One thousand eighty-three healthy adults (63.8% women) aged 70 years and over who participated in the Multidomain Alzheimer Preventive Trial were included. Bodyweight (kg) and PA levels (square root of metabolic equivalent of task-min/week) were assessed repeatedly from baseline to the 3-year visit, whereas plasma GDF-15 (pg/mL) was measured at the 1-year visit. Multiple linear regressions were performed to test the association between first-year mean PA level, 1-year visit GDF-15 concentration and subsequent bodyweight changes. Mediation analyses were used to investigate whether GDF-15 mediated the association between first-year mean PA levels and consecutive bodyweight changes.

RESULTS

Multiple regression analyses demonstrated that higher first-year mean PA levels significantly predicted lower GDF-15 and bodyweight at 1 year (B = -2.22; SE = 0.79; P = 0.005). In addition, higher 1-year visit GDF-15 levels were associated with faster subsequent bodyweight loss (Time × GDF-15 interaction B = -0.0004; SE = 0.0001; P = 0.003). Mediation analyses confirmed that GDF-15 mediated the association between first-year mean PA levels and subsequent bodyweight changes (mediated effect ab = 0.0018; bootstrap SE = 0.001; P < 0.05) and revealed that mean PA had no direct effect on subsequent bodyweight changes (c' = 0.006; SE = 0.008; P > 0.05).

CONCLUSIONS

This study suggests that GDF-15 may be one of the molecules mediating the link between PA and late-life weight loss, but mechanistic studies are necessary to further support the present findings.

Sarcopenia and Ageing

Musculoskeletal ageing is a major health challenge as muscles and bones constitute around 55-60% of body weight. Ageing muscles will result in sarcopenia that is characterized by progressive and generalized loss of skeletal muscle mass and strength with a risk of adverse outcomes. In recent years, a few consensus panels provide new definitions for sarcopenia. It was officially recognized as a disease in 2016 with an ICD-10-CM disease code, M62.84, in the International Classification of Diseases (ICD). With the new definitions, there are many studies emerging to investigate the pathogenesis of sarcopenia, exploring new interventions to treat sarcopenia and evaluating the efficacy of combination treatments for sarcopenia. The scope of this chapter is to summarize and appraise the evidence in terms of (1) clinical signs, symptoms, screening, and diagnosis, (2) pathogenesis of sarcopenia with emphasis on mitochondrial dysfunction, intramuscular fat infiltration and neuromuscular junction deterioration, and (3) current treatments with regard to physical exercises and nutritional supplement.

Vitamin D supplementation and exercise for improving physical function, body composition and metabolic health in overweight or obese older adults with vitamin D deficiency: a pilot randomized, double-blind, placebo-controlled trial

PURPOSE

Vitamin D supplementation may have non-skeletal health benefits and enhance exercise responsiveness, particularly in those with low vitamin D levels. We determined whether, compared with placebo, vitamin D supplementation taken prior to and during a 12-week exercise program improves physical function, body composition or metabolic health, in overweight and obese older adults with vitamin D deficiency.

METHODS

Fifty overweight or obese older adults (mean ± SD age: 60 ± 6 years; BMI 30.6 ± 5.7 kg/m²) with vitamin D deficiency (25-hydroxyvitamin D [25(OH)D] < 50 nmol/L) were recruited. Participants were randomly allocated to receive either vitamin D₃ (4000 IU/day) or matching placebo for 24 weeks. Between weeks 12 and 24, all participants completed multi-modal exercise three days per week while continuing with vitamin D/placebo. Mean changes in physical function (primary outcome: gait speed), body composition and biochemical parameters at weeks 12 and 24 were compared between groups.

RESULTS

Vitamin D supplementation, with or without exercise, had no effect on gait speed. From baseline to week 12, vitamin D supplementation increased serum 25(OH)D levels (placebo: 2.5 ± 14.7 nmol/L; treatment: 43.4 ± 18.4 nmol/L; P < 0.001) and reduced stair climb times (placebo: 0.3 ± 1.0 s; treatment: - 0.2 ± 1.0 s; P = 0.046). From 12 to 24 weeks, vitamin D supplementation combined with exercise decreased waist circumference (placebo: 1.3 ± 7.3 cm; treatment: - 3.0 ± 6.1 cm; P = 0.02) and waist-to-hip ratio (placebo: 0.01 ± 0.05; treatment: - 0.03 ± 0.05; P = 0.01) relative to placebo. Vitamin D supplementation, with or without exercise, had no effect on other physical function, body composition or metabolic health outcomes.

CONCLUSION

Vitamin D supplementation had no effect on most physical function, body composition or metabolic health parameters when taken alone, or during exercise, in overweight or obese older adults with vitamin D deficiency. Vitamin D-related improvements in stair climb times and waist circumference suggest that future trials should explore the effects of vitamin D on muscle power, and its effects on body composition when combined with exercise, in populations with moderate or severe vitamin D deficiency.

Sarcopenic obesity versus sarcopenia alone with the use of probable sarcopenia definition for sarcopenia: Associations with frailty and physical performance

BACKGROUND & AIMS

Ageing brings alterations in body composition, as skeletal muscle gradually declines and accumulation of adipose tissue accompanies it. Although sarcopenia (S) and obesity (O) were separately reported to be associated with frailty and poor physical performance, whether they bring more detrimental or favorable effect when they coexist (i.e. sarcopenic obesity; SO) is an issue needs clarification. We aimed to study the associations of SO and S alone with frailty and poor physical performance, by using probable S definition.

METHODS

This was a retrospective, cross-sectional study including community dwelling older adults who were ≥60 years old and admitted to the outpatient clinic of a tertiary hospital between 2012 and 2020. We measured handgrip strength via hand dynamometer and defined decreased muscle strength as probable S. We performed bioimpedance analysis to evaluate body composition and used fat percentile method to define obesity. We assessed nutritional status via Mini-Nutritional Assessment-Short Form, frailty via FRAIL scale, and physical performance via Timed Up and Go (TUG) test. We examined the associations of four body phenotypes, i.e. non-S non-O, SO, S alone and O alone with frailty and impaired TUG in univariate and multivariate analyses (Model 1). We further performed a head to head analysis of SO vs S to see if one of them was associated more with frailty and impaired TUG (Model 2).

RESULTS

There were 1366 older adults included in the study (mean age: 74.6 ± 6.9; 68.3% female). The prevalences of non-S non-O, S alone, SO and O alone were 53.5, 7.5, 2.8 and 36.2%, respectively. Multivariate analysis adjusted for age, gender and nutritional status revealed that both SO and S alone were independently associated with frailty and impaired TUG, with SO demonstrating lower odds than S alone (OR = 5.9 and 6.05 for frailty, and 3.9 and 4.4 for TUG, respectively). Head-to-head comparison between SO and S alone in Model 2 showed that two groups did not demonstrate significant difference in terms of the frailty and impaired TUG risk.

CONCLUSION

Although SO and S groups demonstrated similar risks, obesity accompanying sarcopenia might show a favorable trend in terms of frailty and poor physical performance, compared to sarcopenia alone. Longitudinal studies are needed to reveal whether an obesity paradox exists for frailty and physical performance in older adults.

Factors of Muscle Quality and Determinants of Muscle Strength: A Systematic Literature Review

Muscle quality defined as the ratio of muscle strength to muscle mass disregards underlying factors which influence muscle strength. The aim of this review was to investigate the relationship of phase angle (PhA), echo intensity (EI), muscular adipose tissue (MAT), muscle fiber type, fascicle pennation angle (θf), fascicle length (lf), muscle oxidative capacity, insulin sensitivity (IS), neuromuscular activation, and motor unit to muscle strength. PubMed search was performed in 2021. The inclusion criteria were: (i) original research, (ii) human participants, (iii) adults (≥18 years). Exclusion criteria were: (i) no full-text, (ii) non-English or -German language, (iii) pathologies. Forty-one studies were identified. Nine studies found a weak−moderate negative (range r: [−0.26]−[−0.656], p < 0.05) correlation between muscle strength and EI. Four studies found a weak−moderate positive correlation (range r: 0.177−0.696, p < 0.05) between muscle strength and PhA. Two studies found a moderate-strong negative correlation (range r: [−0.446]−[−0.87], p < 0.05) between muscle strength and MAT. Two studies found a weak-strong positive correlation (range r: 0.28−0.907, p < 0.05) between θf and muscle strength. Muscle oxidative capacity was found to be a predictor of muscle strength. This review highlights that the current definition of muscle quality should be expanded upon as to encompass all possible factors of muscle quality.

Skelettale Auswirkungen bariatrischer Chirurgie

Bei zunehmender Prävalenz der Adipositas sind in Deutschland ca. 54% der Bevölkerung übergewichtig oder adipös, wobei mit steigendem Übergewicht das Risiko für weitere Erkrankungen, wie z. B. Diabetes mellitus Typ 2, Herzinsuffizienz, arterielle Hypertonie u. a. stark ansteigt. Die Reduktion des Körpergewichtes ist daher aus verschiedenen Gesichtspunkten anzustreben. Viele Patientinnen und Patienten mit Adipositas haben bereits vor einer möglichen Operation einen Mangel an Vitamin D und Calcium und zeigen in Laboruntersuchungen entsprechende Defizite. Die konservative Behandlung der Adipositas aus Ernährungs-, Bewegung- und Verhaltenstherapie bildet die Basis der möglichen Therapiemaßnahmen. Bei Versagen der konservativen Behandlungsoptionen ergibt sich ab einem Body-Mass-Index (BMI) von über 40 kg/m2 die Indikation zur operativen Therapie, ab einem BMI von 50 kg/m2 besteht unter bestimmten Voraussetzungen die primäre Indikation zur Durchführung einer bariatrisch-chirurgischen Maßnahme. Zu den in Deutschland am häufigsten empfohlenen operativen Verfahren, die in der Regel laparoskopisch durchgeführt werden, gehören weiterhin die Implantation eines Magenbands, die Bildung eines Magenschlauchs (Gastric-sleeve-Resektion), die Anlage eines proximalen Roux-en-Y-Magenbypass oder eines Omega-loop-Magenbypass. Neben der angestrebten Reduktion des Übergewichtes durch ihre restriktiven wie malabsorptiven Wirkungen führen diese OP-Methoden in unterschiedlichem Ausmaß zu Veränderungen des Kalzium-Stoffwechsels u. a. mit Hypocalcämie, Vitamin-D-Defizit und Erhöhung des Serum-Parathormons, was in einem erhöhten Frakturrisiko, Veränderungen der Knochendichte und der Mikroarchitektur des Knochens münden kann. In der Nachsorge nach bariatrischen Operationen sind daher eine ausreichende Supplementierung verschiedener Vitamine, Mineralien und Spurenelemente, die regelmäßige Kontrolle der Laborparameter und der Knochendichte sowie ein angepasstes körperliches Training wichtig. Aus osteologischer Sicht kommt bei diagnostizierter Osteoporose insbesondere eine intravenöse antiresorptive Therapie in Betracht.

Association between Fat Distribution and Chronic Low Back Pain among 10,606 Adults: Data from the Korean National Health and Nutrition Examination Survey

Obesity is associated with chronic low back pain (CLBP), but the association between fat distribution and CLBP is unclear. This cross-sectional study evaluated the relationship using the Korean National Health and Nutrition Examination Survey data. A total of 10,606 adults (average age: 45.4, female: 57.1%) were included. We estimated the regional fat distribution, waist circumference, and body fat proportion, compared the values in people with and without CLBP, and stratified the estimates by sex and obesity status using a multivariable linear model. There were no statistically significant differences in the average waist circumference between the people with and without CLBP (p = 0.731) and the average fat proportion between those with and without CLBP (p = 0.731). The average regional fat distribution was significantly higher in the people with CLBP than in those without CLBP, in the upper limbs (11.4%, 95% confidence interval [CI]: [11.3, 11.5] vs. 11.2%, 95% CI: [11.1, 11.3], p < 0.05) and in the lower limbs (31.9%, 95% CI: [31.6, 32.2] vs. 31.4%, 95% CI: [31.2, 31.6], p < 0.01). More obvious among men, fat distribution in the lower limbs is higher than in people without obesity (p < 0.001). People with CLBP tend to have a higher fat distribution in the limbs than those without it and obese people with CLBP would need to reduce the fat in the lower limbs.

Intermuscular adipose tissue in Type 2 diabetes mellitus: Non-invasive quantitative imaging and clinical implications

Intermuscular adipose tissue (IMAT) is an ectopic fat depot found beneath the fascia and within the muscles. IMAT modulates muscle insulin sensitivity and triggers local and systemic chronic low-grade inflammation by producing cytokines and chemokines, which underlie the pathogenesis of Type 2 diabetes mellitus (T2DM). Imaging techniques have been increasingly used to non-invasively quantify IMAT in patients with diabetes in research and healthcare settings. In this study, we systematically reviewed the cell of origin and definition of IMAT, and the use of quantitative and functional imaging technology pertinent to the etiology, risk factors, lifestyle modification, and therapeutic treatment of diabetes. The purpose of this article is to provide important insight into the current understanding of IMAT and future prospects of targeting IMAT for T2DM control.

Prognostic findings for ICU admission in patients with COVID-19 pneumonia: baseline and follow-up chest CT and the added value of artificial intelligence

Infection with SARS-CoV-2 has dominated discussion and caused global healthcare and economic crisis over the past 18 months. Coronavirus disease 19 (COVID-19) causes mild-to-moderate symptoms in most individuals. However, rapid deterioration to severe disease with or without acute respiratory distress syndrome (ARDS) can occur within 1-2 weeks from the onset of symptoms in a proportion of patients. Early identification by risk stratifying such patients who are at risk of severe complications of COVID-19 is of great clinical importance. Computed tomography (CT) is widely available and offers the potential for fast triage, robust, rapid, and minimally invasive diagnosis: Ground glass opacities (GGO), crazy-paving pattern (GGO with superimposed septal thickening), and consolidation are the most common chest CT findings in COVID pneumonia. There is growing interest in the prognostic value of baseline chest CT since an early risk stratification of patients with COVID-19 would allow for better resource allocation and could help improve outcomes. Recent studies have demonstrated the utility of baseline chest CT to predict intensive care unit (ICU) admission in patients with COVID-19. Furthermore, developments and progress integrating artificial intelligence (AI) with computer-aided design (CAD) software for diagnostic imaging allow for objective, unbiased, and rapid assessment of CT images.

Applications of Eccentric Exercise to Improve Muscle and Mobility Function in Older Adults

Muscle aging ultimately leads to the deterioration of human physiological functioning, including declining muscle strength, loss of muscle mass, and decreased quality of life in advanced age. Eccentric exercise is a key intervention that has the potential to ameliorate this problem. Recent studies have focused on evidence-based exercise interventions to prevent declines in muscle strength and physical function in older adults. This paper reviewed relevant literature on the use of eccentric exercise to improve muscle and mobility function in older adults. We explained not only the changes in mobility that occur with aging but also the rationale for and positive effects of eccentric intervention in older adults. We also explored several proposed mechanisms for the intramuscular changes caused by eccentric muscle contraction and considered the safety and side effects accompanying eccentric training. We concluded by suggesting that eccentric exercise is an exercise modality that can potentially improve muscle strength and enhance mobility in older adults.

Physical activity, body mass index, and blood progranulin in older adults: cross-sectional associations in the MAPT study

Physical activity (PA) has been shown to moderate the negative effects of obesity on pro-inflammatory cytokines but its relationship with the adipokine progranulin (PGRN) remains poorly investigated. This study aimed to examine the cross-sectional main and interactive associations of body mass index (BMI) and PA level with circulating PGRN in older adults. Five-hundred and twelve subjects aged 70 years and over involved in the Multidomain Alzheimer Prevention Trial (MAPT) Study who underwent plasma PGRN measurements (ng/ml) were included. Self -reported PA levels were assessed using questionnaires. People were classified into three BMI categories: normal weight, overweight or obesity. Further categorization using PA tertiles was used to define highly active, moderately active and low active individuals. Multiple linear regressions were performed in order to test the associations of BMI, PA level, and their interaction with PGRN levels. Multiple linear regressions adjusted by age, sex, diabetes mellitus status, total cholesterol, creatinine level and MAPT group demonstrated significant interactive associations of BMI status and continuous PA such that in people without obesity, higher PA levels were associated with lower PGRN concentrations, while an opposite pattern was found in individuals with obesity. In addition, continuous BMI was positively associated with circulating PGRN in highly active individuals but not in their less active peers. This cross-sectional study demonstrated reverse patterns in older adults with obesity compared to those without obesity regarding the relationships between PA and PGRN levels. Longitudinal and experimental investigations are required to understand the mechanisms that underlie the present findings.

Multifactorial Mechanism of Sarcopenia and Sarcopenic Obesity. Role of Physical Exercise, Microbiota and Myokines

Obesity and ageing place a tremendous strain on the global healthcare system. Age-related sarcopenia is characterized by decreased muscular strength, decreased muscle quantity, quality, and decreased functional performance. Sarcopenic obesity (SO) is a condition that combines sarcopenia and obesity and has a substantial influence on the older adults’ health. Because of the complicated pathophysiology, there are disagreements and challenges in identifying and diagnosing SO. Recently, it has become clear that dysbiosis may play a role in the onset and progression of sarcopenia and SO. Skeletal muscle secretes myokines during contraction, which play an important role in controlling muscle growth, function, and metabolic balance. Myokine dysfunction can cause and aggravate obesity, sarcopenia, and SO. The only ways to prevent and slow the progression of sarcopenia, particularly sarcopenic obesity, are physical activity and correct nutritional support. While exercise cannot completely prevent sarcopenia and age-related loss in muscular function, it can certainly delay development and slow down the rate of sarcopenia. The purpose of this review was to discuss potential pathways to muscle deterioration in obese individuals. We also want to present the current understanding of the role of various factors, including microbiota and myokines, in the process of sarcopenia and SO.

Malnutrition in Relation to Muscle Mass, Muscle Quality, and Muscle Strength in Hospitalized Older Adults

OBJECTIVES

Muscle quality is an essential muscle metric, which can be assessed by measuring intermuscular adipose tissue (IMAT) and skeletal muscle radiodensity (SMD) via computed tomography (CT) images. We aimed to explore the associations of Global Leadership Initiative on Malnutrition (GLIM)-defined malnutrition with muscle mass, muscle quality, and muscle strength in hospitalized older adults.

DESIGN

A cross-sectional study.

SETTING AND PARTICIPANTS

Hospitalized older patients.

METHODS

Malnutrition was defined by the GLIM criteria after screening by the Mini Nutrition Assessment-Short Form (MNA-SF). Chest CT images were used to segment skeletal muscle area (SMA) and IMAT, and to measure SMD. Skeletal muscle index (SMI) was calculated by SMA (cm²)/body height squared (m²). Handgrip strength (HGS) was measured using a digital dynameter. Univariate and multivariate logistic regression models were performed to calculate odds ratios (ORs) and 95% CIs.

RESULTS

We included 1135 patients. The MNA-SF score is positively associated with SMI, SMD, and HGS, but negatively associated with IMAT. Compared to patients with normal nutrition, patients with malnutrition had significantly lower SMD and HGS in both men and women. Women with malnutrition had significantly higher IMAT than women with normal nutrition, whereas men with malnutrition had significantly lower SMI than men with normal nutrition. After adjustment for confounders, SMI (adjusted OR 0.95, 95% CI 0.93, 0.98), SMD (adjusted OR 0.94, 95% CI 0.93, 0.98), and HGS (adjusted OR 0.91, 95% CI 0.89, 0.94) were significantly and negatively associated with malnutrition. IMAT appeared to be positively associated with malnutrition, but the result was not statistically significant (adjusted OR 1.03, 95% CI 1.00, 1.07).

CONCLUSIONS AND IMPLICATIONS

Our study provides new evidence regarding the association between handgrip strength and malnutrition in older inpatients. Moreover, a small association of chest CT--derived muscle quality and mass with malnutrition is identified.

Cardiometabolic health, visceral fat and circulating irisin levels: results from a real-world weight loss study

BACKGROUND

The aim of this pragmatic intervention study was to investigate changes in cardiometabolic outcomes, irisin plasma concentration, and body composition during a 4-month intervention in unselected obese individuals.

MATERIALS AND METHODS

In 111 obese women aged 36.73 ± 7.2 years, we measured changes in weight, lipid profiles, glucose, insulin, Homeostatic Model Assessment-Insulin Resistance Index (HOMA-IR), uric acid, aminotransferases, and irisin. Body composition including lean mass (LM) and total (TF), gynoid (GF), android (AF), and visceral fat (VF) was assessed using densitometry. Physical activity was assessed using the International Physical Activity Questionnaire (IPAQ). The participants received tailored written advice targeting lifestyle according to current guidelines. At follow-up, patients rated their adherence in the self-administered questionnaire.

RESULTS

Mean weight loss in the whole group was 3.12 kg (- 3.3%); 26% of the women achieved the desired target of weight loss (> 5% of the initial weight), whereas weight decreased moderately in 50% and increased in 14%. In 86 women with weight loss, there were significant changes in HOMA-IR (- 13.8%), insulin (- 11.2%), alanine aminotransferase (- 8.0%), VF (- 7.0%), AF (- 5.4%), TF (- 4.7%), GF (- 2.8%) and LM (- 1.5%), whereas irisin and HDL-C levels and the mean IPAQ score did not change.

CONCLUSIONS

In this real-world evidence study, a successful weight loss achieved only 26% of patients, with overall much better adherence to diet restriction than to exercise. However, even mild to moderate weight loss resulted in significant improvements in cardiometabolic health. Weight loss was associated with a modest LM decrease but did not influence plasma irisin.

Quantification of adipose tissues by Dual-Energy X-Ray Absorptiometry and Computed Tomography in colorectal cancer patients

BACKGROUND & AIMS

Excess adipose tissue may affect colorectal cancer (CRC) patients' disease progression and treatment. In contrast to the commonly used anthropometric measurements, Dual-Energy X-Ray Absorptiometry (DXA) and Computed Tomography (CT) can differentiate adipose tissues. However, these modalities are rarely used in the clinic despite providing high-quality estimates. This study aimed to compare DXA's measurement of abdominal visceral adipose tissue (VAT) and fat mass (FM) against a corresponding volume by CT in a CRC population. Secondly, we aimed to identify the best single lumbar CT slice for abdominal VAT. Lastly, we investigated the associations between anthropometric measurements and VAT estimated by DXA and CT.

METHODS

Non-metastatic CRC patients between 50-80 years from the ongoing randomized controlled trial CRC-NORDIET were included in this cross-sectional study. Corresponding abdominal volumes were acquired by Lunar iDXA and from clinically acquired CT examinations. Also, single CT slices at L2-, L3-and L4-level were obtained. Agreement between the methods was investigated using univariate linear regression and Bland-Altman plots.

RESULTS

Sixty-six CRC patients were included. Abdominal volumetric VAT and FM measured by DXA explained up to 91% and 96% of the variance in VAT and FM by CT, respectively. Bland-Altman plots demonstrated an overestimation of VAT by DXA compared to CT (mean difference of 76 cm³) concurrent with an underestimation of FM (mean difference of -319 cm³). A higher overestimation of VAT (p = 0.015) and underestimation of FM (p = 0.036) were observed in obese relative to normal weight subjects. VAT in a single slice at L3-level showed the highest explained variance against CT volume (R² = 0.97), but a combination of three slices (L2, L3, L4) explained a significantly higher variance than L3 alone (R² = 0.98, p < 0.006). The anthropometric measurements explained between 31-65% of the variance of volumetric VAT measured by DXA and CT.

CONCLUSIONS

DXA and the combined use of three CT slices (L2-L4) are valid to predict abdominal volumetric VAT and FM in CRC patients when using volumetric CT as a reference method. Due to the poor performance of anthropometric measurements we recommend exploring the added value of advanced body composition by DXA and CT integrated into CRC care.

Effect of Aerobic or Resistance Exercise, or Both, on Intermuscular and Visceral Fat and Physical and Metabolic Function in Older Adults with Obesity While Dieting

BACKGROUND

Obesity exacerbates age-related effects on body composition, physical and metabolic function. Which exercise mode is most effective in mitigating these deleterious changes in dieting obese older adults is unknown.

METHODS

In a randomized controlled trial, we performed a head-to-head comparison of aerobic (AEX), resistance (REX), or combination (COMB) exercise during matched weight loss in 160 obese older adults. Prespecified analyses compared 6-month changes in intermuscular adipose tissue (IMAT) and visceral adipose tissue (VAT) assessed using MRI, insulin sensitivity index (ISI) by oral glucose tolerance test, physical function using Modified Physical Performance Test (PPT), VO2peak, gait-speed, and knee strength by dynamometry.

RESULTS

IMAT and VAT decreased more in COMB than AEX and REX groups (IMAT; -41% vs. -28% and -23% and VAT: -36% vs. -19% and -21%; p=.003 to .01); IMAT and VAT decreased in all groups more than control (CON) (between-group p<.001). ISI increased more in COMB than AEX and REX groups (86% vs. 50% and 39%; p=.005 to .03). PPT improved more in COMB than AEX and REX groups, while VO2peak improved more in COMB and AEX than REX group (all p<.05). Knee strength improved more in COMB and REX than AEX group (all p<.05). Changes in IMAT and VAT correlated with PPT (r=-.28 and -.39), VO2peak (r=-.49 and -.52), gait-speed (r=-.25 and -.36), and ISI (r=-.49 and -.52) (all p<.05).

CONCLUSIONS

Weight loss plus combination aerobic and resistance exercise was most effective in improving ectopic fat deposition and physical and metabolic function in older adults with obesity.

Body composition predictors of outcome in patients with COVID-19

BACKGROUND/OBJECTIVE

Obesity is a strong risk factor for adverse outcomes in patients hospitalized with COVID-19, however, the distribution of fat and the amount of muscle mass are more accurate risk factors than BMI. The objective of this study was to assess body composition measures obtained on opportunistic abdominal CTs as predictors of outcome in patients hospitalized with COVID-19. We hypothesized that elevated visceral and intermuscular adipose tissue would be associated with adverse outcome.

SUBJECTS/METHODS

Our retrospective study was IRB-approved and HIPAA-compliant. The study group comprised 124 patients (median age: 68 years, IQR: 56, 77; 59 weeks, 65 months) who were admitted with COVID-19 to a single hospital and who had undergone abdominal CT for clinical purposes. Visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), intermuscular adipose tissue (IMAT), and paraspinal and abdominal muscle cross-sectional areas (CSA) were assessed. Clinical information including prognostic factors, time of admission to the intensive care unit (ICU) and time of death within 28 days were obtained. Multivariate time-to-event competing risk models were fitted to estimate the hazard ratio (HR) for a composite outcome of ICU admission/mortality associated with a one standard deviation increase in each body compositional measure. Each model was adjusted for age, sex, race, BMI, and cardiometabolic comorbidities.

RESULTS

There were 50 patients who were admitted to the ICU or deceased over a median time of 1 day [IQR 1, 6] from hospital admission. Higher VAT/SAT ratio (HR of 1.30; 95% CI 1.04-1.62, p = 0.022) and higher IMAT CSA (HR of 1.44; 95% CI 1.10-1.89, p = 0.008) were associated with a reduced time to ICU admission or death in adjusted models.

CONCLUSION

VAT/SAT and IMAT are predictors of adverse outcome in patients hospitalized with COVID-19, independent of other established prognostic factors. This suggests that body composition measures may serve as novel biomarkers of outcome in patients with COVID-19.

Effect of exercise on myosteatosis in adults: a systematic review and meta-analysis

Muscle tissue typically contains only small amounts of adipose tissue, and the excess deposition of adiposity is considered a pathological phenomenon termed myosteatosis. Several studies have assessed the effects of exercise alone on the severity of myosteatosis, and some studies have reported promising results. We performed a systematic review and meta-analysis to investigate the effects of exercise interventions on myosteatosis (i.e., lipid infiltration and muscle radiation attenuation). Studies were identified through a systematic search of three databases and limited to randomized controlled trials (RCTs) focused on evaluating the effect of exercise interventions on lipid infiltration and/or muscle attenuation in adults. Thirteen studies met the inclusion criteria, and 12 were included in the meta-analysis (n = 465, 84.7% women). The volume of lipid infiltration was decreased in the exercise group compared with the control group [Hedges' g = -0.45, 95% confidence interval (CI), -0.74 to -0.16; P = 0.008, I² = 0%], and the degree of muscle radiation attenuation was increased (Hedges' g = 0.67, 95% CI, 0.22 to 1.13; P = 0.009, I² = 59.3%). Based on meta-regression analyses, there were no significant effects of mean age at baseline (lipid infiltration, β = -0.008, 95% CI, -0.035 to 0.019; P = 0.495; muscle radiation attenuation, β = -0.013, 95% CI, -0.036 to 0.011; P = 0.248) and intervention duration (lipid infiltration, β = -0.008, 95% CI, -0.028 to 0.010; P = 0.311; muscle radiation attenuation, β = -0.018, 95% CI, -0.050 to 0.014; P = 0.230) on the effect size estimates. Overall, our findings indicate that exercise can significantly improve muscle quality in populations at risk of developing obesity and sarcopenia-related disability.NEW & NOTEWORTHY Muscle tissue typically contains only small amounts of adipose tissue, and the excess deposition of adiposity is considered a pathological phenomenon termed myosteatosis. The volume of lipid infiltration tissue was decreased in the exercise group compared with the control group, and muscle attenuation coefficient was increased. Based on the meta-regression analyses, the mean age at baseline and intervention duration did not affect the effect size estimates for lipid infiltration tissue and muscle radiation attenuation.