Association between regional adipose tissue distribution and both type 2 diabetes and impaired glucose tolerance in elderly men and women

White adipose tissue in type 2 diabetes and the effect of antidiabetic drugs

White adipose tissue (WAT) is highly flexible and was previously considered a passive location for energy storage. Its endocrine function has been established for several years, earning it the title of an "endocrine organ" due to its ability to secrete many adipokines that regulate metabolism. WAT is one of the core tissues that influence insulin sensitivity. Its dysfunction enhances insulin resistance and type 2 diabetes (T2D) progression. However, T2D may cause WAT dysfunction, including changes in distribution, metabolism, adipocyte hypertrophy, inflammation, aging, and adipokines and free fatty acid levels, which may exacerbate insulin resistance. This review used PubMed to search WAT dysfunction in T2D and the effects of these changes on insulin resistance. Additionally, we described and discussed the effects of antidiabetic drugs, including insulin therapy, sulfonylureas, metformin, glucose-like peptide-1 receptor agonists, thiazolidinediones, and sodium-dependent glucose transporters-2 inhibitors, on WAT parameters under T2D conditions.

Health Implications Associated with Fat-Free Mass: A Phenome-Wide Mendelian Randomization Study

INTRODUCTION

Fat-free mass (FFM) is a critical component of the human body, with implications for various diseases.

METHODS

We conducted a comprehensive analysis integrating a phenome-wide association study (PheWAS), a two-sample Mendelian randomization (MR) analysis, and a systematic review to investigate the associations between FFM and health outcomes.

RESULTS

PheWAS identified 183 phenotypes enriched for FFM associations, including diseases, body composition, and lifestyle factors. A two-sample MR analysis using the FinnGen and UK Biobank dataset revealed significant associations between genetically determined FFM and 36 disease outcomes, including cardiovascular diseases, metabolic disorders, and musculoskeletal conditions. The mediation MR analysis indicates that FFM indirectly influences the levels of five biomarkers in visceral adipose tissue. A systematic review identified consistent associations between FFM and several diseases, including type 2 diabetes and cervical disc disorders. Moreover, new associations such as low back pain and ovarian cancer were discovered.

CONCLUSION

These findings challenge the conventional notion of FFM as a protective factor in health, suggesting that higher FFM levels may be linked to an increased risk of various diseases. Further clinical studies are warranted to validate these findings and elucidate the underlying mechanisms.

Skeletal muscle adiposity, coronary microvascular dysfunction, and adverse cardiovascular outcomes

BACKGROUND AND AIMS

Skeletal muscle (SM) fat infiltration, or intermuscular adipose tissue (IMAT), reflects muscle quality and is associated with inflammation, a key determinant in cardiometabolic disease. Coronary flow reserve (CFR), a marker of coronary microvascular dysfunction (CMD), is independently associated with body mass index (BMI), inflammation and risk of heart failure, myocardial infarction, and death. The relationship between SM quality, CMD, and cardiovascular outcomes is not known.

METHODS

Consecutive patients (n = 669) undergoing evaluation for coronary artery disease with cardiac stress positron emission tomography demonstrating normal perfusion and preserved left ventricular ejection fraction were followed over a median of 6 years for major adverse cardiovascular events (MACEs), including death and hospitalization for myocardial infarction or heart failure. Coronary flow reserve was calculated as stress/rest myocardial blood flow. Subcutaneous adipose tissue (SAT), SM, and IMAT areas (cm2) were obtained from simultaneous positron emission tomography attenuation correction computed tomography using semi-automated segmentation at the 12th thoracic vertebra level.

RESULTS

Median age was 63 years, 70% were female, and 46% were nonwhite. Nearly half of patients were obese (46%, BMI 30-61 kg/m2), and BMI correlated highly with SAT and IMAT (r = .84 and r = .71, respectively, P < .001) and moderately with SM (r = .52, P < .001). Decreased SM and increased IMAT, but not BMI or SAT, remained independently associated with decreased CFR (adjusted P = .03 and P = .04, respectively). In adjusted analyses, both lower CFR and higher IMAT were associated with increased MACE [hazard ratio 1.78 (95% confidence interval 1.23-2.58) per -1 U CFR and 1.53 (1.30-1.80) per +10 cm2 IMAT, adjusted P = .002 and P < .0001, respectively], while higher SM and SAT were protective [hazard ratio .89 (.81-.97) per +10 cm2 SM and .94 (.91-.98) per +10 cm2 SAT, adjusted P = .01 and .003, respectively]. Every 1% increase in fatty muscle fraction [IMAT/(SM + IMAT)] conferred an independent 2% increased odds of CMD [CFR <2, odds ratio 1.02 (1.01-1.04), adjusted P = .04] and a 7% increased risk of MACE [hazard ratio 1.07 (1.04-1.09), adjusted P < .001]. There was a significant interaction between CFR and IMAT, not BMI, such that patients with both CMD and fatty muscle demonstrated highest MACE risk (adjusted P = .02).

CONCLUSIONS

Increased intermuscular fat is associated with CMD and adverse cardiovascular outcomes independently of BMI and conventional risk factors. The presence of CMD and SM fat infiltration identified a novel at-risk cardiometabolic phenotype.

Association of obesity and LDL subfractions evaluated by body mass index, waist circumference, and diabetes status: the ELSA-Brasil study

Low-density lipoproteins (LDL) comprise a pool of particles with different densities that may have variable impact on atherogenesis. Studies suggest that obese individuals with elevated body mass index (BMI) and waist circumference (WC) have increased small and dense LDL subfractions (sdLDL-c). It is unclear if diabetes (T2D) and insulin resistance (IR) may modify this association. We included 4,111 (50.4 ± 8.6 years of age, 45.5% men) individuals with neither prior cardiovascular disease nor use of lipid-lowering medications. Total LDL-c and its subfractions (LDL1-c, LDL2-c, LDL3-c, and LDL4-c) were measured by vertical zonal ultracentrifugation. We considered the subfractions LDL1-c and LDL2-c as large buoyant LDL (lbLDL-c) and the subfractions LDL3-c and LDL4-c as sdLDL-c. We analyzed the association between LDL-c subclasses, BMI and WC using linear regression analysis and stratified by the presence of T2D and IR. For sdLDL-c, a direct association with hypertension, T2D, fasting plasma glucose, total cholesterol, LDL-c, and triglycerides was observed. In multivariate analysis, after adjustment for age, sex, race and triglycerides, the strong association of sdLDL-c with BMI (β 95% CI 0.16 (0,13-0,19)) and WC (β 95% CI 0.22 (0.19-0.26)) persisted. After stratification, the association of sdLDL-c and WC was present only in those with insulin resistance or diabetes. BMI showed a smaller impact than WC on this association. WC and BMI were strongly associated with sdLDL-c subfractions. Further, this association was modified by diabetes and insulin resistance status.

Maternal age-related declines in live birth rate following single euploid embryo transfer: a retrospective cohort study

PURPOSE

To assess whether maternal age influences the pregnancy outcomes after single frozen euploid embryo transfer.

METHODS

This retrospective analysis was conducted on 1037 cycles of single euploid embryo transfer performed at Nanjing Women and Children's Healthcare Hospital between January 2016 and April 2023. Patients with severe uterine pathologies, immune disorders, or endocrine diseases were excluded. The cycles were categorized into three age groups: <35 years, 35-37 years, and ≥ 38 years. Primary outcomes included live birth rate, clinical pregnancy rate, early pregnancy loss, and miscarriage rate. Data were analyzed using multivariable logistic regression with generalized estimating equations (GEE) to account for confounding factors and restricted cubic splines to visualize the relationship between maternal age and pregnancy outcomes.

RESULTS

Women aged ≥ 38 years demonstrated a significantly diminished live birth rate (41.7%) ,which was lower than that observed in women aged < 35 years (54.5%) and 35-37 years (54.0%), with statistical significance (P < 0.05). Multivariable regression analysis revealed that compared with women aged ≥ 38 years, younger women had reduced risk of miscarriage (aOR = 0.371, 95% CI: 0.139-0.988 for the < 35 years group; aOR = 0.317, 95% CI: 0.106-0.954 for the 35-37 years group) and increased likelihood of live birth (aOR = 2.188, 95% CI: 1.154-4.147 for the < 35 years group; aOR = 2.239, 95% CI: 1.0103-4.548 for the 35-37 years group) after adjusting for relevant confounders. Additionally, the analysis showed that embryos biopsied on day 5 were linked to higher clinical pregnancy rates than those biopsied on day 6, and high-grade blastocysts were associated with superior pregnancy outcomes.

CONCLUSION

Advanced maternal age is associated with a higher miscarriage rate and lower live birth rate following euploid embryo transfer. Despite the exclusion of aneuploidy, age-related factors beyond chromosomal abnormalities appear to impact reproductive outcomes.

INTERMUSCULAR ADIPOSE TISSUE AND MUSCLE FUNCTION IN PATIENTS ON MAINTENANCE HEMODIALYSIS

Background and Aims

Sarcopenia, defined as a loss in muscle mass and strength, is common in patients with advanced chronic kidney disease (CKD), leading to poor outcomes. Intermuscular adipose tissue (IMAT) accumulation is associated with metabolic and functional abnormalities in chronic disease conditions. This study assesses IMAT in maintenance hemodialysis (MHD) patients and its association with metabolic markers and physical performance.

Methods and Results

We performed a cross-sectional study comparing MHD patients with controls. IMAT accumulation was measured by analyzing the fat-to-muscle ratio of the calf muscles through Magnetic Resonance Imaging (MRI) scans. Body composition and metabolic markers were assessed (hs-CRP, TNF-α, IL-6, and insulin resistance). Circulating cell-free mitochondrial DNA (ccf-mtDNA) was quantified using qRT-PCR. Muscle function was evaluated with handgrip strength. Inverse propensity weighted (IPW) method was used to test the difference between IMAT levels of the groups. Twenty-five MHD patients and 23 controls were analyzed. The MHD group had higher IMAT accumulation than controls (p < 0.01). IMAT was positively correlated with Body Mass Index (BMI) and fat mass index (FMI) in controls. MHD patients exhibited elevated TNF-α, IL-6, and hs-CRP levels (p < 0.01). Positive correlations were found between IMAT and IL-6 in MHD patients and between IMAT and TNF-α in controls. Handgrip strength was negatively correlated with IMAT in the entire cohort (p <0.01).

Conclusion

Our findings highlight the potential role of IMAT in muscle catabolism and functional decline in advanced CKD. Targeting IMAT could be a valuable strategy for improving health outcomes in this population.

Higher abdominal fat area associates with lower donor kidney function before and after living kidney donation

Central body fat distribution affects kidney function. Abdominal fat measurements using computed tomography (CT) may prove superior in assessing body composition-related kidney risk in living kidney donors. This retrospective cohort study including 550 kidney donors aimed to determine the association between CT-measured abdominal fat areas and kidney function before and after donor nephrectomy. Donors underwent glomerular filtration rate measurements (125I-Iothalamate, mGFR) before and 3 months after donation. Linear regression analyses with body surface area (BSA)-standardized and crude mGFR were performed to assess the association of height-indexed tomographic fat measurements with kidney function. In age-, and sex-adjusted analyses higher levels of total abdominal, visceral, subcutaneous, and intramuscular adipose tissue index were significantly associated with lower mGFR levels before donation (BSA-standardized mGFR: visceral adipose tissue index: Βeta=-0.11, p < 0.001, subcutaneous: Βeta=-0.10, p < 0.001, intramuscular: Βeta=-1.18, p < 0.001, total abdominal: Βeta=-0.07, p < 0.001). Higher tomographic abdominal fat is associated with lower BSA-standardized mGFR after donation and a greater decrease in mGFR between screening and 3 months post-donation. This study shows that CT-measured abdominal fat area is associated with kidney function before and after living kidney donation.

FAPs orchestrate homeostasis of muscle physiology and pathophysiology

As a common clinical manifestation, muscle weakness is prevalent in people with mobility disorders. Further studies of muscle weakness have found that patients with muscle weakness present with persistent muscle inflammation, loss of muscle fibers, fat infiltration, and interstitial fibrosis. Therefore, we propose the concept of muscle microenvironment homeostasis, which explains the abnormal pathological changes in muscles through the imbalance of muscle microenvironment homeostasis. And we identified an interstitial progenitor cell FAP during the transition from normal muscle microenvironment homeostasis to muscle microenvironment imbalance caused by muscle damage diseases. As a kind of pluripotent stem cell, FAPs do not participate in myogenic differentiation, but can differentiate into fibroblasts, adipocytes, osteoblasts, and chondrocytes. As a kind of mesenchymal progenitor cell, it is involved in the generation of extracellular matrix, regulate muscle regeneration, and maintain neuromuscular junction. However, the muscle microenvironment is disrupted by the causative factors, and the abnormal activities of FAPs eventually contribute to the complex pathological changes in muscles. Targeting the mechanisms of these muscle pathological changes, we have identified appropriate signaling targets for FAPs to improve and even treat muscle damage diseases. In this review, we propose the construction of muscle microenvironmental homeostasis and find the key cells that cause pathological changes in muscle after homeostasis is broken. By studying the mechanism of abnormal differentiation and apoptosis of FAPs, we found a strategy to inhibit the abnormal pathological changes in muscle damage diseases and improve muscle regeneration.

Gender-specific capacity of insulin resistance proxies to predict functional decline in older adults

OBJECTIVES

Insulin resistance determined by Homeostasis Model of Insulin Resistance (HOMA-IR) has been associated with functional decline in non-diabetic older subjects. However, insulin is not routinely assessed. The study evaluated the predictive value of non-insulin-dependent IR surrogates on functional decline in non-diabetic older men and women.

DESIGN AND PARTICIPANTS

Prospective cohort study over 5 years. The study included 615 older participants from the Toledo Study of Healthy Aging.

METHODS

Frailty was assessed by the Frailty Trait Scale-5 (FTS-5) at baseline and after 5 years follow-up. 193 subjects experienced functional decline (2.5-point reduction in the FTS-5 score). Multivariate regression models analysed the effect of five described IR surrogates on functional decline considering potential confounders.

RESULTS

Among evaluated IR proxies, triglyceride glucose-body mass index (TyG-BMI) and HOMA-IR were significantly associated with an increased risk of functional decline (odd ratio (95% confidence interval) TyG-BMI: 1.16 (1.05, 1.28), p = 0.0035 and HOMA-IR: 1.59 (1.15, 2.21), p = 0.0056) among all participants. When stratified by gender, HOMA-IR was related to functional decline in men [2.02 (1.13, 3.59), p = 0.0173] and TyG-BMI in women [1.19 (1.05, 1.35), p = 0.0057].

CONCLUSIONS

Only TyG-BMI index mimics the predictive capacity of insulin-based IR marker. The predictive ability of IR indexes is gender-specific, being TyG-BMI the only index able to predict functional decline in women and HOMA-IR in men.

Association between heart failure in asymptomatic stages and skeletal muscle function assessed by ultrasonography in community-dwelling older adults

BACKGROUND

Symptomatic heart failure (HF) negatively affects the quantity and quality of skeletal muscles. However, the association between asymptomatic HF and skeletal muscle function remains unclear. We aimed to use ultrasonography to elucidate the association between asymptomatic HF and skeletal muscle function in community-dwelling older adults.

METHODS

This cross-sectional study comprised community-dwelling older adults aged ≥ 60 years who could perform activities of daily living independently and had never had symptomatic HF (n = 52, 76.3 ± 6.1 years). The participants were classified into three groups namely, non-HF (n = 26), stage A (n = 19), and stage B (n = 7) according to the HF stage criteria of the American Heart Association /American College of Cardiology /Heart Failure Society of America guideline. Skeletal muscle quantity and quality were assessed using ultrasonography (thickness and echo intensity) of the rectus femoris (RF) and vastus intermedius (VI) muscles. The group effects on muscle thickness and echo intensity in each group were assessed using a multivariate analysis.

RESULTS

Both muscles consistently demonstrated significant group effects on the thickness and echo intensity. Thicknesses of the RF (p = 0.020) and VI (p = 0.035) were lower in the stage B group than that in the non-HF group. The echo intensities in the RF (p = 0.006) and VI (p = 0.009) were higher in the stage B group than that in the non-HF group.

CONCLUSION

Asymptomatic HF negatively associated with the characteristics of skeletal muscle function, as assessed by ultrasonography in community-dwelling older adults. The stage B HF contributes to reduced skeletal muscle function as well as symptomatic HF.

Sex differences in plasma lipid profiles, but not in glucose metabolism in patients with first-episode antipsychotics-naïve schizophrenia

BACKGROUND

First-episode antipsychotics-naïve schizophrenia (FEAN-SCZ) is associated with abnormalities in glucose and lipid metabolism. While sex differences in the incidence and severity of SCZ and metabolic abnormalities have been documented, the specific metabolic abnormalities between the sexes remain unclear. The study aimed to investigate sex-specific differences in plasma glycolipid profiles in FEAN-SCZ patients.

METHODS

A total of 172 FEAN-SCZ patients (male/female: 83/89) and 31 healthy controls (male/female: 14/17) were recruited. Psychopathology assessment was conducted using the Positive and Negative Syndrome Scale (PANSS). Glycolipid profiles, including oral glucose tolerance test (OGTT), fasting glucose, insulin, total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) were examined in all participants.

RESULTS

FEAN patients displayed significantly higher fasting and 2-hour glucose levels compared to healthy controls (both p < 0.001). Impaired glucose tolerance (IGT) prevalence in male patients was 24.1 % (n = 20) and 25.9 % (n = 23) in females, contrasting with 0 % (n = 0) in the control group. FEAN patients exhibited elevated blood insulin and TC levels (both p < 0.05) and increased insulin resistance measured by HOMA-IR (p < 0.01). Among male patients, those with IGT had significantly higher TC, TG and LDL levels than non-IGT patients (all p < 0.05), while no significant differences were observed in female patients between IGT and non-IGT groups. Body mass index (BMI), TG and HDL levels were identified as significant predictors of IGT in male FEAN patients.

CONCLUSIONS

IGT is present in a subset of FEAN-SCZ patients. Male patients with IGT exhibit distinct alterations in plasma lipid profiles compared to non-IGT patients.

Body composition and late-occurring chronic health conditions after autologous stem cell transplantation for lymphoma

BACKGROUND

Autologous peripheral blood stem cell transplantation (aPBSCT) is the standard of care for adults with relapsed lymphoma, yet recipients remain at risk of developing chronic health conditions (CHCs). It was hypothesized that body composition measurements of skeletal muscle and fat are associated with late-onset CHCs and nonrelapse mortality after aPBSCT.

METHODS

Leveraging the Blood or Marrow Transplant Survivor Study, we examined association between pre-aPBSCT body composition and new-onset grade 3-5 CHCs among 187 adults with lymphoma treated with aPBSCT (2011-2014) surviving ≥2 years after aPBSCT. Using computed tomography scans at the L3 level, skeletal muscle mass (skeletal muscle area and skeletal muscle density [SMD]) and body fat (subcutaneous adipose tissue and visceral adipose tissue) were measured and quantified as sex-specific z-scores. Competing risk models were built to study the impact of body composition on incident grade 3 through 5 CHCs and nonrelapse mortality (NRM) adjusting for confounders.

RESULTS

The study cohort had a median age at aPBSCT of 57 years with 63% males, 77% non-Hispanic Whites and 81% with non-Hodgkin lymphoma. The 5-year cumulative incidence of grade 3 through 5 CHCs was 47% (95% Confidence Interval, CI, 38%-56%). Each SD increase in SMD was associated with 30% reduced risk of grade 3 through 5 CHCs (95% CI, 0.50-0.96). The 10-year cumulative incidence of NRM was 16% (95% CI, 10-22). No body composition measure was associated with NRM.

CONCLUSIONS

The association between SMD and grade 3 through 5 CHCs following aPBSCT could inform development of prognostic models to identify adults with lymphoma at greatest risk of morbidity following aPBSCT.

Body composition as a determinant of the therapeutic index with androgen signaling inhibition

BACKGROUND

Androgen signaling is central to prostate cancer and men's health. Prior data indicates that increasing body fat is unfavorable in the localized setting yet associated with favorable outcomes in men with metastatic disease. Understanding the biological links between adiposity and prostate cancer may optimize the therapeutic index with ASI. We hypothesized that host adiposity and androgen synthesis are linked to the efficacy and toxicity of ASI for men with metastatic castration-resistant prostate cancer (mCRPC).

METHODS

A post-hoc analysis was done of NCT02703623 where men with mCRPC (n = 186) were treated for 8 weeks with abiraterone acetate, prednisone, and apalutamide (AAPA), and a satisfactory response was defined as a PSA decline >50%. Body composition was measured on baseline CT scans. Germline DNA WES was performed with a focus on variants in steroidogenic genes. Adipokine levels were measured in pre-treatment plasma.

RESULTS

Germline polymorphisms in 3 genes involved in androgen synthesis (AKR1C3 rs12529, CYP17A1 rs6162, SRD5A2 rs523349) were associated with differences in body composition at baseline on ADT alone (prior to receipt of AAPA). Elevated subcutaneous adipose tissue index (SATi, p = 0.02), visceral adipose tissue index (VATi, p = 0.03), and BMI (p = 0.04) were associated with satisfactory response to AAPA. Leptin had positive correlation with VATi (r = 0.47) and SATi (r = 0.48).

CONCLUSION

Inherited polymorphisms in androgen synthesis correlated with differences in body composition after exposure to ADT and warrant further investigation as candidate markers for body composition toxicity. Elevated subcutaneous and visceral adiposity were associated with improved response to ASI.

Impaired skeletal muscle regeneration in diabetes: From cellular and molecular mechanisms to novel treatments

Diabetes represents a major public health concern with a considerable impact on human life and healthcare expenditures. It is now well established that diabetes is characterized by a severe skeletal muscle pathology that limits functional capacity and quality of life. Increasing evidence indicates that diabetes is also one of the most prevalent disorders characterized by impaired skeletal muscle regeneration, yet underlying mechanisms and therapeutic treatments remain poorly established. In this review, we describe the cellular and molecular alterations currently known to occur during skeletal muscle regeneration in people with diabetes and animal models of diabetes, including its associated comorbidities, e.g., obesity, hyperinsulinemia, and insulin resistance. We describe the role of myogenic and non-myogenic cell types on muscle regeneration in conditions with or without diabetes. Therapies for skeletal muscle regeneration and gaps in our knowledge are also discussed, while proposing future directions for the field.

Analysis of Risk Factors for the Association of Sarcopenia in Patients with Type 2 Diabetes Mellitus

Background

Previous studies have shown that the prevalence of sarcopenia in patients with type 2 diabetes mellitus (T2DM) has increased significantly over the years. However, the risk factors for the association of sarcopenia in patients with T2DM are unknown. Therefore, we attempted to investigate the risk factors through measurement and analysis of the patients' data from April 2020 to April 2022.

Methods

A total of 334 hospitalized patients with T2DM were divided into sarcopenia group (n=101) and non-sarcopenia group (n=233). Clinical factors were compared between the two groups and also between the two genders. Receiver operating characteristic curve (ROC) was used to analyze the ROC diagnostic ability of related factors in sarcopenia.

Results

(1) Among the 334 patients, the overall prevalence of sarcopenia was 30.2%; 41.3% in men and 20.1% in women. (2) The multifactorial logistic regression analysis showed that gender (specifically for men; OR=4.997, 95% CI: 2.611-9.564), low body mass index (BMI) (OR=1.525, 95% CI: 1.353-1.718), lower 25(OH)D levels (OR=1.076, 95% CI:1.036-1.117), and lower IGF-1 (OR=1.013, 95% CI:1.006-1.020) were independent risk factors (P < 0.05). (3) ROC curve analysis results showed that BMI, 25 (OH) D, IGF-1, and testosterone (for men) had predictive significance for sarcopenia with T2DM (P < 0.05). However, the AUC of 25 (OH) D, IGF-1 and testosterone (for men) were all <0.7, while the AUC of BMI and the combined factors were all >0.7, has great predictive significance.

Conclusion

The prevalence of sarcopenia in hospitalized patients with T2DM is higher in men than in women. Low BMI and lower serum levels of 25 (OH) D and IGF-1 are risk factors of sarcopenia in patients with T2DM. Low BMI, 25(OH)D, IGF-1, and testosterone (for men) all contributed to the prediction of sarcopenia, among which BMI and combined factors were more significant.

Fat Mass Accounts for Insulin Resistance Impact on Functional Decline and Mortality in Nondiabetic Older Adults

OBJECTIVE

To assess the potential role of body composition in the association of insulin resistance (IR) with functional decline and mortality in nondiabetic older persons.

DESIGN

Longitudinal population-based cohort of community-dwelling people from Toledo, Spain, aged 65 years or older.

SETTING AND PARTICIPANTS

A total of 1114 nondiabetic persons from the Toledo Study of Healthy Aging cohort (mean age: 74.5, 56.10% female) with complete data at baseline were included. Only 914 participants had fully assessment of functional evaluation during the follow-up period.

METHODS

IR was determined by the homeostasis model assessment index (HOMA-IR) at baseline while frailty was assessed by the Frailty Trait Scale-5 (FTS-5) at baseline and after 2.99 years' median follow-up period. A total of 319 participants experienced functional decline (2.5-point reduction in the FTS-5 score). A total of 143 deaths were recorded (6.31 years median follow-up) from the Spanish National Death Index. Body compositions were determined using dual-energy x-ray absorptiometry. Multivariate regression models analyzed the effect of HOMA-IR on outcomes, with age, sex, Charlson index, and number of medications included in the basic adjustment model.

RESULTS

A 1-logaritmic unit increment in HOMA-IR increased the risk of functional decline after basic adjustment [odds ratio (95% confidence interval): 1.41 (1.09-1.83), P = .009]. This significant association was lost when further adjusted for total fat mass [1.14 (0.86-1.50)] and trunk fat mass [1.03 (0.77-1.37)], which accounted for 62.92% and 91.49% of the association. HOMA-IR was inversely associated with mortality risk [hazard ratio 0.66 (0.49-0.87), P = .0037], an association lost after adjustment for total fat mass [0.74 (0.55-1.01)] and trunk fat mass [0.80 (0.58-1.09)], accounting for 29.05% and 45.78% of the association. Adjustment by lean mass did not modify any of the associations.

CONCLUSIONS AND IMPLICATIONS

Body fat mass, especially in the trunk region, mediates the association of IR with functional decline and to a lesser extent with reduced risk of mortality in nondiabetic older subjects.

Prevalence of and Impact on the Outcome of Myosteatosis in Patients with Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

Limited data exist on the prevalence of myosteatosis (i.e., excess accumulation of fat in skeletal muscles) in hepatocellular carcinoma (HCC) patients, and no systematic review or meta-analysis has been conducted in this context.

METHODS

We searched for articles published from inception until November 2023 to assess the prevalence of myosteatosis in patients with HCC.

RESULTS

Ten studies with 3316 patients focusing on myosteatosis and HCC were included. The overall prevalence of myosteatosis in HCC patients was 50% [95% Confidence Interval (CI): 35-65%]. Using the body mass index-based criteria (two studies), the prevalence was 34%, while gender-based criteria (eight studies) yielded 54% (p = 0.31). In Asian studies (n = 8), the prevalence was 45%, compared to 69% in non-Asian countries (two studies) (p = 0.02). For viral-associated HCC (eight studies), the prevalence was 49%, rising to 65% in non-alcoholic fatty liver disease-associated cases (three studies) and 86% in alcoholic liver disease-associated cases (three studies) (p < 0.01). The prevalence of myosteatosis was higher in Child-Pugh class C (3 studies, 91%) than in A (7 studies, 73%) or B (6 studies, 50%) (p = 0.02), but with no difference between Barcelona Clinic Liver Cancer stage A (3 studies, 66%), B (4 studies, 44%) and C (3 studies, 62%) (p = 0.80). Patients with myosteatosis had a significantly higher mortality (six studies) (Relative Risk: 1.35 (95%CI: 1.13-1.62, p < 0.01).

CONCLUSION

The prevalence of myosteatosis is high in HCC patients and is associated with more severe liver disease and higher mortality rates.

The relationship between fat distribution and diabetes in US adults by race/ethnicity

Introduction

This study examined the relationship between fat distribution and diabetes by sex-specific racial/ethnic groups.

Methods

A secondary data analysis of National Health and Nutrition Examination Survey 2011-2018 data (n = 11,972) was completed. Key variables examined were visceral adipose tissue area (VATA), subcutaneous fat area (SFA), diabetes prevalence, and race/ethnicity. The association of VATA and SFA and diabetes prevalence was examined separately and simultaneously using multiple logistic regression. Bonferroni corrections were applied to all multiple comparisons between racial/ethnic groups. All analyses were adjusted for demographics and muscle mass.

Results

VATA was positively associated with diabetes in both sexes (p < 0.001) and across all racial/ethnic groups (p < 0.05) except Black females. No statistically significant relationships were observed between SFA and diabetes while accounting for VATA with the exception of White females (p = 0.032). When comparing racial/ethnic groups, the relationship between VATA and diabetes was stronger in White and Hispanic females than in Black females (p < 0.005) while the relationship between SFA and diabetes did not differ between any racial/ethnic groups.

Conclusion

This study found that VATA is associated with diabetes for both sexes across almost all racial/ethnic groups independent of SFA whereas the only significant relationship between SFA and diabetes, independent of VATA, was observed in White females. The findings indicated that visceral fat was more strongly associated with diabetes than subcutaneous. Additionally, there are health disparities in sex-specific racial/ethnic groups thus further study is warranted.

Association of daily carbohydrate intake with intermuscular adipose tissue in Korean individuals with obesity: a cross-sectional study

BACKGROUND/OBJECTIVES

The prevalence of obesity, a worldwide pandemic, has been increasing steadily in Korea. Reports have shown that increased intermuscular adipose tissue (IMAT) is associated with an increased risk of cardiovascular disease, independent of body mass index. However, the relationship between dietary intake and IMAT accumulation in the Korean population remains undetermined. The objective of this study was to evaluate regional fat compartments using advanced magnetic resonance imaging (MRI) techniques. We also aimed to investigate the association between IMAT amounts and dietary intake, including carbohydrate intake, among Korean individuals with obesity.

SUBJECTS/METHODS

This cross-sectional study, performed at a medical center in South Korea, recruited 35 individuals with obesity (15 men and 20 women) and classified them into 2 groups according to sex. Anthropometry was performed, and body fat distribution was measured using MRI. Blood parameters, including glucose and lipid profiles, were analyzed using commercial kits. Linear regression analysis was used to test whether the IMAT was associated with daily carbohydrate intake.

RESULTS

Carbohydrate intake was positively associated with IMAT in all individuals, with adjustments for age, sex, height, and weight. No significant differences in blood indicators were found between the sexes.

CONCLUSIONS

Regardless of sex and age, higher carbohydrate intake was strongly correlated with greater IMAT accumulation. This suggests the need to better understand sex differences and high carbohydrate diet patterns in relation to the association between obesity and metabolic risk, which may help reduce obesity prevalence.

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.

Carnosine supplementation improves glucose control in adults with pre-diabetes and type 2 diabetes: A randomised controlled trial

BACKGROUND AND AIMS

Type 2 diabetes (T2DM) is a major cause of morbidity and mortality globally. Carnosine, a naturally occurring dipeptide, has anti-inflammatory, antioxidant, and anti-glycating effects, with preliminary evidence suggesting it may improve important chronic disease risk factors in adults with cardiometabolic conditions.

METHODS AND RESULTS

In this randomised controlled trial, 43 adults (30%F) living with prediabetes or T2DM consumed carnosine (2 g) or a matching placebo daily for 14 weeks to evaluate its effect on glucose metabolism assessed via a 2-h 75 g oral glucose tolerance test. Secondary outcomes included body composition analysis by dual energy x-ray absorptiometry (DEXA), calf muscle density by pQCT, and anthropometry. Carnosine supplementation decreased blood glucose at 90 min (-1.31 mmol/L; p = 0.02) and 120 min (-1.60 mmol/L, p = 0.02) and total glucose area under the curve (-3.30 mmol/L; p = 0.04) following an oral glucose tolerance test. There were no additional changes in secondary outcomes. The carnosine group results remained significant before and after adjustment for age, sex, and change in weight (all>0.05), and in further sensitivity analyses accounting for missing data. There were no significant changes in insulin levels.

CONCLUSION

This study provides preliminary support for larger trials evaluating carnosine as a potential treatment for prediabetes and the initial stages of T2DM. Likely mechanisms may include changes to hepatic glucose output explaining the observed reduction in blood glucose without changes in insulin secretion following carnosine supplementation.

Myosteatosis as a novel predictor of new-onset diabetes mellitus after kidney transplantation

OBJECTIVES

We evaluate the effect of myosteatosis on new-onset diabetes mellitus after kidney transplantation.

METHODS

Consecutive patients who had renal transplant between 2006 and 2021 were reviewed, and 219 patients were finally included. Psoas muscle index was used to evaluate sarcopenia and average total psoas density (calculated by computed tomography before surgery) for myosteatosis. We used Cox proportional regression analyses in investigation of whether skeletal muscle depletion before surgery inclusive of sarcopenia and myosteatosis is a new additional predictor of new-onset diabetes mellitus.

RESULTS

Median recipient age and body mass index were 45 years and 21.1 kg/m2 , respectively, and 123 patients (56%) were male. Preoperative impaired glucose tolerance was present in 58 patients (27%) and new-onset diabetes mellitus in 30 patients (14%), with median psoas muscle index of 6 cm2 /m2 and average total psoas density of 41 Hounsfield Unit. In multivariate analysis, significant risk factors were body mass index ≥25 kg/m2 (p < 0.01), impaired glucose tolerance (p < 0.01), and average total psoas density < 41.9 Hounsfield Unit (p = 0.03). New-onset diabetes mellitus had incidence rates of 3.7% without risk factors, 10% with a single risk factor, 33% with two, and 60% with three. Patients with new-onset diabetes mellitus were effectively stratified by the number of risk factors (p < 0.01).

CONCLUSIONS

Myosteatosis could be a new risk factor used to predict new-onset diabetes mellitus.

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.

Association between Asymptomatic Hyperuricemia with Adiposity Indices: A Cross-Sectional Study in a Spanish Population

INTRODUCTION

New anthropometric indices have been developed as an alternative to body mass index (BMI) and waist circumference (WC) to assess body mass and visceral fat. Asymptomatic hyperuricemia is considered an independent cardiovascular risk factor. Currently, little is known about the relationship between asymptomatic hyperuricemia and several new anthropometric indices. This study aimed to assess the association between the presence of asymptomatic hyperuricemia and anthropometric indices, both novel and traditional.

METHODS

This study analyzed 1094 Spanish subjects who consecutively visited the cardiovascular risk consultation of the University Hospital San Pedro de Alcántara of Cáceres, Spain, between June 2021 and September 2022. Anthropometric measures, including traditional and novel indices, were determined. The asymptomatic hyperuricemia group was defined according to serum uric acid levels.

RESULTS

All the anthropometric indices studied, including new and traditional, were significantly greater among patients with asymptomatic hyperuricemia, except for WWI. In multiple linear regression analysis, serum uric acid levels were significantly correlated with BMI, WHR, WHtR, AVI, BAI, BRI, CUN-BAE, and WWI but not ABSI or CI. In the univariate analysis, all indices were associated with asymptomatic hyperuricemia (p < 0.05); however, only WHtR (adjusted OR: 2.93; 95% CI: 1.03-8.37; p = 0.044), AVI (adjusted OR: 1.46; 95% CI: 1.04-2.04; p = 0.026), and BRI (adjusted OR: 1.66; 95% CI: 1.19-2.32; p = 0.003) were significantly associated in multivariate analysis. Finally, WHtR, AVI, and BRI provided the largest AUCs.

CONCLUSIONS

Our findings showed that WHtR, AVI, and BRI were independently positively associated with asymptomatic hyperuricemia and could be good predictors.

Type 2 Diabetes Mellitus and Sarcopenia as Comorbid Chronic Diseases in Older Adults: Established and Emerging Treatments and Therapies

Type 2 diabetes mellitus (T2DM) and sarcopenia (low skeletal muscle mass and function) share a bidirectional relationship. The prevalence of these diseases increases with age and they share common risk factors. Skeletal muscle fat infiltration, commonly referred to as myosteatosis, may be a major contributor to both T2DM and sarcopenia in older adults via independent effects on insulin resistance and muscle health. Many strategies to manage T2DM result in energy restriction and subsequent weight loss, and this can lead to significant declines in muscle mass in the absence of resistance exercise, which is also a first-line treatment for sarcopenia. In this review, we highlight recent evidence on established treatments and emerging therapies targeting weight loss and muscle mass and function improvements in older adults with, or at risk of, T2DM and/or sarcopenia. This includes dietary, physical activity and exercise interventions, new generation incretin-based agonists and myostatin-based antagonists, and endoscopic bariatric therapies. We also highlight how digital health technologies and health literacy interventions can increase uptake of, and adherence to, established and emerging treatments and therapies in older adults with T2DM and/or sarcopenia.

Intermuscular adipose tissue in obesity and related disorders: cellular origins, biological characteristics and regulatory mechanisms

Intermuscular adipose tissue (IMAT) is a unique adipose depot interspersed between muscle fibers (myofibers) or muscle groups. Numerous studies have shown that IMAT is strongly associated with insulin resistance and muscular dysfunction in people with metabolic disease, such as obesity and type 2 diabetes. Moreover, IMAT aggravates obesity-related muscle metabolism disorders via secretory factors. Interestingly, researchers have discovered that intermuscular brown adipocytes in rodent models provide new hope for obesity treatment by acting on energy dissipation, which inspired researchers to explore the underlying regulation of IMAT formation. However, the molecular and cellular properties and regulatory processes of IMAT remain debated. Previous studies have suggested that muscle-derived stem/progenitor cells and other adipose tissue progenitors contribute to the development of IMAT. Adipocytes within IMAT exhibit features that are similar to either white adipocytes or uncoupling protein 1 (UCP1)-positive brown adipocytes. Additionally, given the heterogeneity of skeletal muscle, which comprises myofibers, satellite cells, and resident mesenchymal progenitors, it is plausible that interplay between these cellular components actively participate in the regulation of intermuscular adipogenesis. In this context, we review recent studies associated with IMAT to offer insights into the cellular origins, biological properties, and regulatory mechanisms of IMAT. Our aim is to provide novel ideas for the therapeutic strategy of IMAT and the development of new drugs targeting IMAT-related metabolic diseases.

Thigh-hip ratio is significantly associated with all-cause mortality among Japanese community-dwelling men

Anthropometric evaluation is a simple yet essential indicator of muscle and fat mass when studying life prognosis in aging. This study aimed to investigate the contributions of anthropometric measurements, independent of body mass index, to measures of all-cause mortality. We examined data for 1,704 participants from the 2014 Nomura Cohort Study who attended follow-ups for the subsequent eight years (follow-up rate: 93.0%). Of these, 765 were male (aged 69 ± 11 years) and 939 were female (aged 69 ± 9 years). The Japanese Basic Resident Registry provided data on adjusted relative hazards for all-cause mortality. The data were subjected to a Cox regression analysis, wherein the time variable was age and the risk factors were gender, age, anthropometric index, smoking habits, drinking habits, exercise habits, cardiovascular history, hypertension, lipid levels, diabetes, renal function, and serum uric acid. Of the total number of participants, 158 (9.3%) were confirmed to have died, and of these, 92 were male (12.0% of all male participants) and 66 were female (7.0% of all female participants). The multivariable Cox regression analysis revealed that a smaller thigh-hip ratio predicted eight-year all-cause mortality in male participants, but only baseline body mass index was associated with all-cause mortality in female participants. Thigh-hip ratio is a useful predictor of death in Japanese community-dwelling men.

Arsenic disrupts extracellular vesicle-mediated signaling in regenerating myofibers

Chronic exposure to environmental arsenic is a public health crisis affecting hundreds of millions of individuals worldwide. Though arsenic is known to contribute to many pathologies and diseases, including cancers, cardiovascular and pulmonary diseases, and neurological impairment, the mechanisms for arsenic-promoted disease remain unresolved. This is especially true for arsenic impacts on skeletal muscle function and metabolism, despite the crucial role that skeletal muscle health plays in maintaining cardiovascular health, systemic homeostasis, and cognition. A barrier to researching this area is the challenge of interrogating muscle cell-specific effects in biologically relevant models. Ex vivo studies investigating mechanisms for muscle-specific responses to arsenic or other environmental contaminants primarily utilize traditional 2-dimensional culture models that cannot elucidate effects on muscle physiology or function. Therefore, we developed a contractile 3-dimensional muscle construct model-composed of primary mouse muscle progenitor cells differentiated in a hydrogel matrix-to study arsenic exposure impacts on skeletal muscle regeneration. Muscle constructs exposed to low-dose (50 nM) arsenic exhibited reduced strength and myofiber diameter following recovery from muscle injury. These effects were attributable to dysfunctional paracrine signaling mediated by extracellular vesicles (EVs) released from muscle cells. Specifically, we found that EVs collected from arsenic-exposed muscle constructs recapitulated the inhibitory effects of direct arsenic exposure on myofiber regeneration. In addition, muscle constructs treated with EVs isolated from muscles of arsenic-exposed mice displayed significantly decreased strength. Our findings highlight a novel model for muscle toxicity research and uncover a mechanism of arsenic-induced muscle dysfunction by the disruption of EV-mediated intercellular communication.

White Adipose Tissue Heterogeneity in the Single-Cell Era: From Mice and Humans to Cattle

Adipose tissue is a major modulator of metabolic function by regulating energy storage and by acting as an endocrine organ through the secretion of adipokines. With the advantage of next-generation sequencing-based single-cell technologies, adipose tissue has been studied at single-cell resolution, thus providing unbiased insight into its molecular composition. Recent single-cell RNA sequencing studies in human and mouse models have dissected the transcriptional cellular heterogeneity of subcutaneous (SAT), visceral (VAT), and intramuscular (IMAT) white adipose tissue depots and revealed unique populations of adipose tissue progenitor cells, mature adipocytes, immune cell, vascular cells, and mesothelial cells that play direct roles on adipose tissue function and the development of metabolic disorders. In livestock species, especially in bovine, significant gaps of knowledge remain in elucidating the roles of adipose tissue cell types and depots on driving the pathogenesis of metabolic disorders and the distinct fat deposition in VAT, SAT, and IMAT in meat animals. This review summarizes the current knowledge on the transcriptional and functional cellular diversity of white adipose tissue revealed by single-cell approaches and highlights the depot-specific function of adipose tissue in different mammalian species, with a particular focus on recent findings and future implications in cattle.

Sex Difference in the Associations among Obesity-Related Indices with Hyperuricemia in a Large Taiwanese Population Study

Hyperuricemia has been linked with the development of diabetes, gout, kidney, and cardiovascular diseases. Although obesity is associated with hyperuricemia, data on sex differences in this association are scarce. Therefore, this study was conducted to explore sex differences in the correlations among various indices of obesity with hyperuricemia in Taiwan. Data were obtained from the Taiwan Biobank and included 122,067 participants. After excluding 179 participants with missing data, the remaining 121,888 participants (men: 43,790; women: 78,098) were enrolled. The prevalence rates of hyperuricemia (defined as serum uric acid >7.0/6.0 mg/dL in men/women) were 29.8% and 13.6%, respectively (p < 0.001). Multivariable analysis revealed high values of body shape index (ABSI), waist-to-height ratio (WHtR), waist-hip ratio (WHR), lipid accumulation product (LAP), conicity index (CI), visceral adiposity index (VAI), body adiposity index (BAI), abdominal volume index (AVI), body mass index (BMI), and body roundness index (BRI) were significantly associated with hyperuricemia in both the male and female participants (all p < 0.001). The interactions between sex and all 10 of these indices were significant (all p < 0.001) for hyperuricemia. In men, LAP had the highest area under the curve (0.669), followed by BMI (0.655), VAI (0.645), AVI (0.642), BRI (0.640), WHtR (0.633), BAI (0.605), WHR (0.599), CI (0.574), and ABSI (0.510). In women, LAP also had the highest area under the curve (0.754), followed by BMI (0.728), VAI (0.724), WHtR (0.721), BRI (0.720), AVI (0.713), WHR (0.676), BAI (0.673), CI (0.626), and ABSI (0.544). In conclusion, obesity-related indices were associated with hyperuricemia in this large Taiwanese study, and sex differences were found in these associations, with stronger associations in women than in men.

Hedgehog signaling via its ligand DHH acts as cell fate determinant during skeletal muscle regeneration

Successful muscle regeneration relies on the interplay of multiple cell populations. However, the signals required for this coordinated intercellular crosstalk remain largely unknown. Here, we describe how the Hedgehog (Hh) signaling pathway controls the fate of fibro/adipogenic progenitors (FAPs), the cellular origin of intramuscular fat (IMAT) and fibrotic scar tissue. Using conditional mutagenesis and pharmacological Hh modulators in vivo and in vitro, we identify DHH as the key ligand that acts as a potent adipogenic brake by preventing the adipogenic differentiation of FAPs. Hh signaling also impacts muscle regeneration, albeit indirectly through induction of myogenic factors in FAPs. Our results also indicate that ectopic and sustained Hh activation forces FAPs to adopt a fibrogenic fate resulting in widespread fibrosis. In this work, we reveal crucial post-developmental functions of Hh signaling in balancing tissue regeneration and fatty fibrosis. Moreover, they provide the exciting possibility that mis-regulation of the Hh pathway with age and disease could be a major driver of pathological IMAT formation.

Quantification of Extramyocellular Lipids and Intramuscular Fat from Muscle Echo Intensity in Lower Limb Muscles: A Comparison of Four Ultrasound Devices against Magnetic Resonance Spectroscopy

This study aimed to compare different ultrasound devices with magnetic resonance spectroscopy (MRS) to quantify muscle lipid content from echo intensity (EI). Four different ultrasound devices were used to measure muscle EI and subcutaneous fat thickness in four lower-limb muscles. Intramuscular fat (IMF), intramyocellular (IMCL) and extramyocellular lipids (EMCL) were measured using MRS. Linear regression was used to compare raw and subcutaneous fat thickness-corrected EI values to IMCL, EMCL and IMF. IMCL had a poor correlation with muscle EI (r = 0.17-0.32, NS), while EMCL (r = 0.41-0.84, p < 0.05-p < 0.001) and IMF (r = 0.49-0.84, p < 0.01-p < 0.001) had moderate to strong correlation with raw EI. All relationships were improved when considering the effect of subcutaneous fat thickness on muscle EI measurements. The slopes of the relationships were similar across devices, but there were some differences in the y-intercepts when raw EI values were used. These differences disappeared when subcutaneous fat thickness-corrected EI values were considered, allowing for the creation of generic prediction equations (r = 0.41-0.68, p < 0.001). These equations can be used to quantify IMF and EMCL within lower limb muscles from corrected-EI values in non-obese subjects, regardless of the ultrasound device used.

Intermuscular Adiposity is Associated with Coronary Microvascular Dysfunction Independently of Body Mass Index and Modifies its Effect on Adverse Cardiovascular Outcomes

Background: Skeletal muscle (SM) fat infiltration, or intermuscular adipose tissue (IMAT), reflects muscle quality and is associated with inflammation, a key determinant in cardiometabolic disease. Coronary flow reserve (CFR), a marker of coronary microvascular dysfunction (CMD), is independently associated with BMI, inflammation and risk of heart failure, myocardial infarction and death. We sought to investigate the relationship between skeletal muscle quality, CMD and cardiovascular outcomes. Methods: Consecutive patients (N=669) undergoing evaluation for CAD with cardiac stress PET demonstrating normal perfusion and preserved left ventricular ejection fraction were followed over median 6 years for major adverse cardiovascular events (MACE), including death and hospitalization for myocardial infarction or heart failure. CFR was calculated as stress/rest myocardial blood flow and CMD defined as CFR<2. Subcutaneous adipose tissue (SAT), SM and IMAT areas (cm ² ) were obtained from simultaneous PET attenuation correction CTs using semi-automated segmentation at the twelfth thoracic vertebra (T12) level. Results: Median age was 63 years, 70% were female and 46% nonwhite. Nearly half of patients were obese (46%, BMI 30-61) and BMI correlated highly with SAT and IMAT (r=0.84 and 0.71, respectively, p<0.001) and moderately with SM (r=0.52, p<0.001). Decreased SM and increased IMAT, but not BMI or SAT, remained independently associated with decreased CFR (adjusted p=0.03 and p=0.04, respectively). In adjusted analyses, both lower CFR and higher IMAT were associated with increased MACE [HR 1.78 (1.23-2.58) per -1U CFR and 1.53 (1.30-1.80) per +10 cm ² IMAT, adjusted p=0.002 and p<0.0001, respectively], while higher SM and SAT were protective [HR 0.89 (0.81-0.97) per +10 cm ² SM and 0.94 (0.91-0.98) per +10 cm ² SAT, adjusted p=0.01 and 0.003, respectively]. Every 1% increase in fatty muscle fraction [IMAT/(SM+IMAT)] conferred an independent 2% increased odds of CMD [CFR<2, OR 1.02 (1.01-1.04), adjusted p=0.04] and a 7% increased risk of MACE [HR 1.07 (1.04-1.09), adjusted p<0.001]. There was a significant interaction between CFR and IMAT, not BMI, such that patients with both CMD and fatty muscle demonstrated highest MACE risk (adjusted p=0.02). Conclusion: Increased intermuscular fat is associated with CMD and adverse cardiovascular outcomes independently of BMI and conventional risk factors. The presence of CMD and skeletal muscle fat infiltration identified a novel at-risk cardiometabolic phenotype.

The Important Role of Intermuscular Adipose Tissue on Metabolic Changes Interconnecting Obesity, Ageing and Exercise: A Systematic Review

As age increases, adipose tissue infiltrates muscle tissue and leads to sarcopenia. When excessive accumulation of adipose tissue accompanied progressive decrease in lean body mass especially visceral fat, termed as sarcopenic obesity (SO) and related metabolic intermuscular adipose tissue (IMAT) is an ectopic tissue found between muscle groups, and is distinct from subcutaneous adipose tissue. Until now, the association between IMAT and metabolic health was not understood. This study is the first systematic review assessing the association between IMAT and metabolic health. The PubMed, Science Direct and Cochrane databases were searched for studies reporting IMAT and metabolic risk. The descriptions of the extracted data are guided by the Preferred Reporting Items for Systematic Reviews (PRISMA) statement with a Grading of Recommendations Assessment, Development and Evaluation approach. This study is registered at PROSPERO (identifier: CRD42022337518). Six studies were pooled and reviewed using critical appraisal by the Newcastle Ottawa Scale and Centre for Evidence-Based Medicine checklist. Two clinical trials and four observational trials were included. Our results reveal that IMAT is associated with metabolic risk, especially in older adults and patients with obesity. However, in a person with abdominal obesity, VAT has a more significant role in metabolic risk than IMAT. The largest decrease in IMAT was achieved by combining aerobic with resistance training.

Association between Skeletal Muscle Mass-to-Visceral Fat Ratio and Dietary and Cardiometabolic Health Risk Factors among Korean Women with Obesity

Sarcopenic obesity (SO) is more associated with cardiovascular diseases than sarcopenia or obesity alone. This study aimed to assess the association between the skeletal muscle mass-to-visceral fat area ratio (SVR) and dietary and cardiometabolic health risk factors in obese women. Fifty-nine women aged 19-65 years with BMI values of ≥25 kg/m² and <32 kg/m² were included. The SVR was inversely correlated with blood lipids (total cholesterol, β = -0.369, p = 0.022; low-density lipoprotein cholesterol, β = -0.326, p = 0.049) and hs-CRP (β = -0.305, p = 0.043). Among the dietary factors, fatty acid intake (saturated fatty acids (SFA), β = -0.287, p = 0.044; monounsaturated fatty acids (MUFA), β = -0.282, p = 0.048; polyunsaturated fatty acids (PUFA), β = -0.301, p = 0.035) was inversely correlated with the SVR. Conversely, vitamin B₆ and B₁₂ intake (vitamin B₆, β = 0.338, p = 0.012; vitamin B₁₂, β = 0.281, p = 0.024) showed positive associations with the SVR. Individuals with a lower SVR were more likely to have SO and higher blood lipids and inflammatory marker levels. Regarding dietary factors, the SVR increased with vitamin B₆ and B₁₂ intake, which was less likely to occur in individuals with SO.

Modeling the effects of genetic- and diet-induced obesity on melanoma progression in zebrafish

Obesity is a rising concern and associated with an increase in numerous cancers, often in a sex-specific manner. Preclinical models are needed to deconvolute the intersection between obesity, sex and melanoma. Here, we generated a zebrafish system that can be used as a platform for studying these factors. We studied how germline overexpression of Agrp along with a high-fat diet affects melanomas dependent on BRAFV600E and loss of p53. This revealed an increase in tumor incidence and area in male, but not female, obese fish, consistent with the clinical literature. We then determined whether this was further affected by additional somatic mutations in the clinically relevant genes rb1 or ptena/b. We found that the male obesogenic effect on melanoma was present with tumors generated with BRAF;p53;Rb1 but not BRAF;p53;Pten. These data indicate that both germline (Agrp) and somatic (BRAF, Rb1) mutations contribute to obesity-related effects in melanoma. Given the rapid genetic tools available in the zebrafish, this provides a high-throughput system to dissect the interactions of genetics, diet, sex and host factors in obesity-related cancers.

Triglyceride-Glucose Index as a Potential Indicator of Sarcopenic Obesity in Older People

PURPOSE

This population-based cross-sectional study aimed to determine whether the triglyceride-glucose index (TyG index) is associated with sarcopenic obesity (SO) and whether it would be a helpful indicator of SO.

METHODS

A total of 3821 participants aged ≥ 60 years were selected for the study group, and 4919 participants aged 20-39 years were included as a reference group. The participants were allocated to sarcopenia, obesity, and SO groups depending on if their body mass index (BMI) was ≥25 kg/m² and their sarcopenia index was ≤1 standard deviation (SD) lower than the mean of the reference group. The sex-specific differences and trends among the participants were analyzed by using the TyG index tertiles, and appropriate cut-off values of the TyG index for SO were calculated.

RESULTS

As the TyG index increased, BMI increased, but the sarcopenia index decreased in both sexes. Males and females in the middle and highest tertiles of the TyG index were 1.775 and 3.369, and they were 1.993 and 3.157 times more likely to have SO, respectively. The cut-off values of the TyG index for SO in males and females were ≥8.72 and 8.67, respectively.

CONCLUSION

A high TyG index is positively associated with SO, and the TyG index may be considered a potential indicator of SO.

Interactive effects of intrinsic capacity and obesity on the KDIGO chronic kidney disease risk classification in older patients with type 2 diabetes mellitus

BACKGROUND

Intrinsic capacity (IC) is a novel concept focusing on normal and healthy aging. The effect of IC on the risk of chronic kidney disease (CKD) according to KDIGO category in older type 2 diabetes mellitus (T2DM) patients has rarely been studied. We investigated whether a decline in IC is associated with the risk of CKD according to KDIGO 2012 categories.

METHODS

This is a cross-sectional study. The exposure variables (IC score and body mass index) and outcome variable (KDIGO categories of the risk of CKD) were collected at the same timepoint. A total of 2482 older subjects with T2DM managed through a disease care program were enrolled. The five domains of IC, namely locomotion, cognition, vitality, sensory, and psychological capacity were assessed. Based on these domains, the IC composite score was calculated. CKD risk was classified according to the KDIGO 2012 CKD definition. Univariate and multivariate analyses were used to assess the association between IC score and KDIGO categories of risk of CKD.

RESULTS

The KDIGO CKD risk category increased in parallel with IC score (p for trend < 0.0001). In multivariate analysis, compared to those with an IC score 0, the odds ratio of having a KDIGO moderately increased to very high risk category of CKD was 1.76 (1.31-2.37) times higher for those with an IC score of 2-5. Furthermore, an increased IC score was associated with a higher prevalence of moderate and severe obesity. Moreover, there was a synergistic interaction between IC score and obesity on the KDIGO moderately increased to very high risk category of CKD (synergy index = 1.683; 95% CI 0.630-3.628), and the proportion of the KDIGO moderately increased to very high risk category of CKD caused by this interaction was 25.6% (attributable proportion of interaction = 0.256).

CONCLUSIONS

Our findings indicate that IC score may be closely related to the KDIGO moderately increased to very high risk category of CKD. In addition, there may be a synergistic interaction between IC score and obesity, and this synergistic interaction may increase the KDIGO CKD risk stage.

Vitamin D Deficiency in Both Oral and Systemic Manifestations in SARS-CoV-2 Infection: Updated Review

The specialized literature emphasizes the fact that vitamin D has a potentially beneficial effect in the context of the current COVID-19 pandemic. The purpose of this article is to highlight the role of vitamin D, both prophylactic and curative, in the treatment of patients diagnosed with COVID-19. Even though its relevance is still unknown and causes various controversies, there is currently no specific treatment for patients diagnosed with COVID-19. There are various prevention strategies with new vaccination schedules, but additional randomized and clinical trials are still needed to combat this pandemic. In addition to the systemic manifestations of SARS-CoV-2 infection, oral manifestations of this disease have also been described in the literature. The etiology of oral manifestations associated with COVID-19 infection and vitamin D deficiency remains controversial. In the present studies, oral manifestations such as salivary gland infections, aphthae, erythema, gingivitis, ulcers, etc. have been reported. This is a new topic, and the prevalence of manifestations is described in only a few studies, which is inconsistent with the number of COVID-19 cases reported since the beginning of the pandemic. The clinical symptomatology in patients with current COVID-19 infection is polymorphic. Whether the oral manifestation is directly caused by SARS-CoV-2 or a secondary manifestation remains an important topic to analyze and discuss.

Intermuscular adipose tissue in metabolic disease

Intermuscular adipose tissue (IMAT) is a distinct adipose depot described in early reports as a 'fatty replacement' or 'muscle fat infiltration' that was linked to ageing and neuromuscular disease. Later studies quantifying IMAT with modern in vivo imaging methods (computed tomography and magnetic resonance imaging) revealed that IMAT is proportionately higher in men and women with type 2 diabetes mellitus and the metabolic syndrome than in people without these conditions and is associated with insulin resistance and poor physical function with ageing. In parallel, agricultural research has provided extensive insight into the role of IMAT and other muscle lipids in muscle (that is, meat) quality. In addition, studies using rodent models have shown that IMAT is a bona fide white adipose tissue depot capable of robust triglyceride storage and turnover. Insight into the importance of IMAT in human biology has been limited by the dearth of studies on its biological properties, that is, the quality of IMAT. However, in the past few years, investigations have begun to determine that IMAT has molecular and metabolic features that distinguish it from other adipose tissue depots. These studies will be critical to further decipher the role of IMAT in health and disease and to better understand its potential as a therapeutic target.

Differences of Regional Fat Distribution Measured by Magnetic Resonance Imaging According to Obese Phenotype in Koreans

Background: Obesity is commonly associated with a high risk of metabolic disorders, and obesity-related metabolic abnormalities are affected by some specific obesity phenotypes, regional fat distribution, and body mass index. However, few studies have investigated the relationship between obesity phenotypes and regional fat distribution in Korean subjects. This study aimed to assess regional fat distribution by gender using magnetic resonance imaging (MRI), and to identify a link between fat distribution and metabolic disorders in Korean subjects. Methods: This study included 35 Korean subjects (20 women, 15 men) who were classified into two groups by gender, and further divided into two groups based on their obesity phenotype: a metabolically abnormal obesity (MAO) and metabolically healthy obesity (MHO) group. Fat distribution was measured using MRI. The blood parameters were measured using a commercially available kit. Results: Women in the MAO group had more risk factors for metabolic abnormalities than those in the MHO group. Serum glucose, triglyceride, and high-density lipoprotein cholesterol (HDL-C) levels were also significantly higher in women with MAO than in those with MHO. The intermuscular adipose tissue (IMAT) of women with MAO was significantly higher than that of women with MHO. Serum HDL-C level was negatively correlated with IMAT, whereas leptin showed a positive correlation with IMAT in all subjects. Conclusions: Metabolic abnormalities according to obesity phenotype posed a higher risk in women than that in men. These findings suggest that an understanding of gender differences in relation to the association between obesity and metabolic risk would be helpful to reduce the prevalence of obesity.

Intermuscular adipose tissue in patients with systemic lupus erythematosus

OBJECTIVE

Patients with SLE frequently have debilitating fatigue and reduced physical activity. Intermuscular adipose tissue (IMAT) accumulation is associated with reduced physical exercise capacity. We hypothesised that IMAT is increased in patients with SLE and associated with increased fatigue, reduced physical activity and increased inflammation.

METHODS

In a cross-sectional study, 23 patients with SLE and 28 control participants were evaluated. IMAT was measured in the calf muscles using sequential T ₁-weighted MRI. Patient-reported physical activity and fatigue were measured and a multiplex proteomic assay was used to measure markers and mediators of inflammation.

RESULTS

IMAT accumulation (percentage of IMAT area to muscle area) was significantly higher in SLE versus control participants (7.92%, 4.51%-13.39% vs 2.65%, 1.15%-4.61%, median, IQR, p<0.001) and remained significant after adjustment for age, sex, race and body mass index (p<0.001). In patients with SLE, IMAT accumulation did not differ significantly among corticosteroid users and non-users (p=0.48). In the study cohort (patients and controls), IMAT was positively correlated with self-reported fatigue score (rho=0.52, p<0.001) and inversely correlated with self-reported walking distance (rho=-0.60, p<0.001). Several markers of inflammation were associated with IMAT accumulation in patients with SLE, and gene ontology analysis showed significant enrichment for pathways associated with macrophage migration and activation in relation to IMAT.

CONCLUSION

Patients with SLE have greater IMAT accumulation than controls in the calf muscles. Increased IMAT is associated with greater fatigue and lower physical activity. Future studies should evaluate the effectiveness of interventions that improve muscle quality to alleviate fatigue in patients with SLE.

Evaluation of risk factors and diseases associated with metabolic and atherosclerotic disorders in different abdominal fat distribution patterns assessed by CT-scan

INTRODUCTION

Obesity is defined as an increase in body fat composition.

Visceral fat loss by whole-body electromyostimulation is attenuated in male and absent in female older Non-Insulin-Dependent diabetes patients

INTRODUCTION

Type 2 diabetes and its reversal correlate with increases and decreases in visceral fat (VF). Resistance exercise reduces VF in healthy persons, but little is known in type 2 diabetes. Muscle contractions induced by whole-body electromyostimulation (WB-EMS) provide a very effective form of resistance training. We hypothesized that WB-EMS reduces VF and improves plasma glucose measures in older non-insulin dependent diabetes mellitus (NIDDM) males and females.

METHODS

A four-arm age-matched case control study was done on WB-EMS twice a week in older NIDDM patients (27 males, 18 females) compared with controls (15 males, 15 females). VAT area (VAT, cm² ), total fat mass (TFM, kg) and lean body mass (LBM, kg) were assessed by DEXA-scanning. HbA1c, fasting glucose and plasma lipoproteins were measured at baseline and after 4 months.

RESULTS

Baseline control VAT was higher in males than females (140.5 ± 35.6 vs. 96.7 ± 42.3, p < .001). In NIDDM, VAT was higher with no significant sex difference (206.5 ± 65.0 vs. 186.5 ± 60.5). In controls, WBEMS reduced VAT in males and females to similar extent (-16.9% and -16.4%, p < .001 vs. baseline) and in preference to TFM (-9.2% and -3.6%) or body weight loss (-2.8 and -2.1%). In NIDDM, VF loss was attenuated in males (-7.3%, p < .01) but completely absent in females. WBEMS reduced HbA1c and cholesterol and increased HDL levels (all p < .05) only in male NIDDM CONCLUSIONS: WBEMS induced VF loss in healthy older males and females an effect strongly attenuated in male and completely absent in female NIDDM patients. This questions the effectiveness of muscle contraction-induced VF lipolysis in NIDDM. Sex differences may dictate the success of resistance training in NIDDM, a subject that needs to be addressed in future studies.

Mediation effects of diabetes and inflammation on the relationship of obesity to cognitive impairment in African Americans

BACKGROUND

Whether diabetes and adipokine-driven inflammation explain the association of obesity to cognitive impairment is unknown.

METHODS

Structural equation models estimated the total effects of waist circumference on cognitive outcomes among African American participants cross-sectionally (index exam) and longitudinally. Total effects were deconstructed into direct pathways of waist circumference to cognitive impairment and indirect mediation pathways through leptin, soluble tumor necrosis factor receptor 2 (sTNFR2), and diabetes. Waist circumference, leptin, and sTNFR2 were standardized. Cognitive impairment was defined as MMSE <21 or a z-score < -1.5 standard deviation (SD). Incident cognitive impairment was defined among those without cognitive impairment at the index exam as follow-up MMSE<21, z- score < -1.5, MMSE decline >1 point/year, or z-score decline of >0.1 SD/year.

RESULTS

Among 1008 participants (70% women, mean age 62.9 years, 14.5% with obesity, 26% with diabetes), 132 (13%) had baseline cognitive impairment. Each SD higher waist circumference was associated with higher odds of cognitive impairment, odds ratio (OR) = 1.63; (95% confidence interval: 1.17, 2.24), with mediating pathways explaining 65% of the total effect (58% from diabetes; 7% from inflammation). At follow-up (mean 6.8 years), 106 of 535 (19.8%) had developed cognitive impairment. Each SD higher waist circumference was associated with higher odds of developing cognitive impairment (OR = 1.87; 95%CI: 1.18, 2.74); the direct effect of waist circumference explained 37% of the total effect and mediating pathways explained 63% (61% from diabetes; 2% from inflammation), although individual pathways were not statistically supported in the smaller sample.

CONCLUSION

Diabetes, and to a lesser degree, adiposity-driven inflammation, appear to explain a substantial proportion of abdominal adiposity relationships with cognitive impairment. The impact of preventing and treating obesity on cognitive outcomes merits study.

The acromegaly lipodystrophy

Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) are essential to normal growth, metabolism, and body composition, but in acromegaly, excesses of these hormones strikingly alter them. In recent years, the use of modern methodologies to assess body composition in patients with acromegaly has revealed novel aspects of the acromegaly phenotype. In particular, acromegaly presents a unique pattern of body composition changes in the setting of insulin resistance that we propose herein to be considered an acromegaly-specific lipodystrophy. The lipodystrophy, initiated by a distinctive GH-driven adipose tissue dysregulation, features insulin resistance in the setting of reduced visceral adipose tissue (VAT) mass and intra-hepatic lipid (IHL) but with lipid redistribution, resulting in ectopic lipid deposition in muscle. With recovery of the lipodystrophy, adipose tissue mass, especially that of VAT and IHL, rises, but insulin resistance is lessened. Abnormalities of adipose tissue adipokines may play a role in the disordered adipose tissue metabolism and insulin resistance of the lipodystrophy. The orexigenic hormone ghrelin and peptide Agouti-related peptide may also be affected by active acromegaly as well as variably by acromegaly therapies, which may contribute to the lipodystrophy. Understanding the pathophysiology of the lipodystrophy and how acromegaly therapies differentially reverse its features may be important to optimizing the long-term outcome for patients with this disease. This perspective describes evidence in support of this acromegaly lipodystrophy model and its relevance to acromegaly pathophysiology and the treatment of patients with acromegaly.

Abdominal Visceral Adipose Tissue and All-Cause Mortality: A Systematic Review

Introduction

Increased abdominal visceral adipose tissue (VAT) implies an adverse cardio-metabolic profile. We examined the association of abdominal VAT parameters and all-cause mortality risk.

Methods

We systematically searched four databases. We performed citations/articles screening, data abstraction, and quality assessment in duplicate and independently (CRD42020205021).

Results

We included 12 cohorts, the majority used computed tomography to assess abdominal VAT area. Six cohorts with a mean age ≤ 65 years, examining all-cause mortality risk per increment in VAT area (cm2) or volume (cm3), showed a 11-98% relative risk increase with higher VAT parameters. However, the association lost significance after adjusting for glycemic indices, body mass index, or other fat parameters. In 4 cohorts with a mean age >65 years, the findings on mortality were inconsistent. Conversely, in two cohorts (mean age 73-77 years), a higher VAT density, was inversely proportional to VAT area, and implied a higher mortality risk.

Conclusion

A high abdominal VAT area seems to be associated with increased all-cause mortality in individuals ≤ 65 years, possibly mediated by metabolic complications, and not through an independent effect. This relationship is weaker and may reverse in older individuals, most likely secondary to confounding bias and reverse causality. An individual participant data meta-analysis is needed to confirm our findings, and to define an abdominal VAT area cutoff implying increased mortality risk.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=205021, identifier CRD42020205021.

Quantifying the inflammatory secretome of human intermuscular adipose tissue

Adipose tissue secretes an abundance of lipid and protein mediators, and this secretome is depot-specific, with local and systemic effects on metabolic regulation. Intermuscular adipose tissue (IMAT) accumulates within the skeletal muscle compartment in obesity, and is associated with insulin resistance and metabolic disease. While the human IMAT secretome decreases insulin sensitivity in vitro, its composition is entirely unknown. The current study was conducted to investigate the composition of the human IMAT secretome, compared to that of the subcutaneous (SAT) and visceral adipose tissue (VAT) depots. IMAT, SAT, and VAT explants from individuals with obesity were used to generate conditioned media. Proteomics analysis of conditioned media was performed using multiplex proximity extension assays, and eicosanoid analysis using liquid chromatography-tandem mass spectrometry. Compared to SAT and/or VAT, IMAT secreted significantly more cytokines (IL2, IL5, IL10, IL13, IL27, FGF23, IFNγ and CSF1) and chemokines (MCP1, IL8, CCL11, CCL20, CCL25 and CCL27). Adipokines hepatocyte growth factor and resistin were secreted significantly more by IMAT than SAT or VAT. IMAT secreted significantly more eicosanoids (PGE2, TXB2 , 5-HETE, and 12-HETE) compared to SAT and/or VAT. In the context of obesity, IMAT is a distinct adipose tissue with a highly immunogenic and inflammatory secretome, and given its proximity to skeletal muscle, may be critical to glucose regulation and insulin resistance.

Factors influencing thigh muscle volume change with cycling exercises in acute spinal cord injury - a secondary analysis of a randomized controlled trial

Objective: To conduct a per-protocol analysis on thigh muscle volume outcomes from the Spinal Cord Injury and Physical Activity (SCIPA) Switch-On Trial.Design: Secondary analysis from an assessor-blind randomized, controlled trial.Setting: Four acute/sub-acute hospitals in Australia and New Zealand.Participants: 24 adults (1 female) within four weeks of motor complete or incomplete spinal cord injury (SCI)Intervention: Functional electrical stimulation-assisted cycling (FESC) or passive cycling (PC) 4x/week for 12 weeks.Outcome Measures: Whole thigh and muscle group volumes calculated from manually segmented MR images.Results: 19/24 participants completed ≥ twelve weeks of the intervention. Five participants experienced hypertrophy (4 FESC; 1 PC) and eight attenuation of atrophy (<20% volume loss) (3 FESC; 5 PC) in thigh muscle volume. Six participants were non-responders, exhibiting atrophy >20% (3 FESC; 3 PC). Mean (SD) change for FESC was -2.3% (25.3%) and PC was -14.0% (12.3%). After controlling for baseline muscle volumes, a strong significant correlation was found between mean weekly exercise frequency and quadriceps and hamstring volumes (r=6.25, P=0.006), regardless of mode. Average watts was highly correlated to quadriceps volumes only (r=5.92, P=0.01), while total number of sessions was strongly correlated with hamstring volumes only (r=5.91, P=0.01).Conclusion: This per-protocol analysis of FESC and PC early after SCI reports a partial response in 42% and a beneficial response in 25% of patients who completed 12 weeks intervention, regardless of mode. Strong correlations show a dose-response according to exercise frequency. Characteristics of non-responders are discussed to inform clinical decision-making.