Distribution of subcutaneous and intermuscular fatty tissue of the mid-thigh measured by MRI-A putative indicator of serum adiponectin level and individual factors of cardio-metabolic risk

Reevaluating Adiponectin's impact on obesity hypertension: a Chinese case-control study

BACKGROUND

Obesity and hypertension are major risk factors for cardiovascular diseases that affect millions of people worldwide. Both conditions are associated with chronic low-grade inflammation, which is mediated by adipokines such as adiponectin. Adiponectin is the most abundant adipokine that has a beneficial impact on metabolic and vascular biology, while high serum concentrations are associated with some syndromes. This "adiponectin paradox" still needs to be clarified in obesity-associated hypertension. The aim of this study was to investigate how adiponectin affects blood pressure, inflammation, and metabolic function in obesity hypertension using a Chinese adult case-control study.

METHODS

A case-control study that had finished recruiting 153 subjects divided as four characteristic groups. Adiponectin serum levels were tested by ELISA in these subjects among these four characteristic Chinese adult physical examination groups. Waist circumference (WC), body mass index (BMI), systolic blood pressure (SB), diastolic blood pressure (DB), and other clinical laboratory data were collected. Analyzation of correlations between the research index and differences between groups was done by SPSS.

RESULTS

Serum adiponectin levels in the| normal healthy group (NH group) were significantly higher than those in the newly diagnosed untreated just-obesity group (JO group), and negatively correlated with the visceral adiposity index. With multiple linear egression analysis, it was found that, for serum adiponectin, gender, serum albumin (ALB), alanine aminotransferase (ALT) and high-density lipoprotein cholesterol (HDLC) were the significant independent correlates, and for SB, age and HDLC were the significant independent correlates, and for DB, alkaline phosphatase (ALP) was the significant independent correlate. The other variables did not reach significance in the model.

CONCLUSIONS

Our study reveals that adiponectin's role in obesity-hypertension is multifaceted and is influenced by the systemic metabolic homeostasis signaling axis. In obesity-related hypertension, compensatory effects, adiponectin resistance, and reduced adiponectin clearance from impaired kidneys and liver all contribute to the "adiponectin paradox".

Predictors of visceral and subcutaneous adipose tissue and muscle density: The ShapeUp! Kids study

BACKGROUND AND AIMS

Body fat distribution, i.e., visceral (VAT), subcutaneous adipose tissue (SAT) and intramuscular fat, is important for disease prevention, but sex and ethnic differences are not well understood. Our aim was to identify anthropometric, demographic, and lifestyle predictors for these outcomes.

METHODS AND RESULTS

The cross-sectional ShapeUp!Kids study was conducted among five ethnic groups aged 5-18 years. All participants completed questionnaires, anthropometric measurements, and abdominal MRI scans. VAT and SAT areas at four lumbar levels and muscle density were assessed manually. General linear models were applied to estimate coefficients of determination (R2) and to compare the fit of VAT and SAT prediction models. After exclusions, the study population had 133 male and 170 female participants. Girls had higher BMI-z scores, waist circumference (WC), and SAT than boys but lower VAT/SAT and muscle density. SAT, VAT, and VAT/SAT but not muscle density differed significantly by ethnicity. R2 values were higher for SAT than VAT across groups and improved slightly after adding WC. For SAT, R2 increased from 0.85 to 0.88 (girls) and 0.62 to 0.71 (boys) when WC was added while VAT models improved from 0.62 to 0.65 (girls) and 0.57 to 0.62 (boys). VAT values were significantly lower among Blacks than Whites with little difference for the other groups.

CONCLUSION

This analysis in a multiethnic population identified BMI-z scores and WC as the major predictors of MRI-derived SAT and VAT and highlights the important ethnic differences that need to be considered in diverse populations.

A sex-specific association of leukocyte telomere length with thigh muscle mass

OBJECTIVES

Telomeres are DNA-protein complexes at the ends of linear chromosomes that protect against DNA degradation. Telomeres shorten during normal cell divisions and therefore, telomere length is an indicator of mitotic-cell age. In humans, telomere shortening is a potential biomarker for disease risk, progression and premature death. Physical activity has been associated with longer leukocyte telomere length (LTL) in some studies. In the current study the relationship between LTL, thigh muscle mass and adipose tissue distribution was explored.

METHODS

We performed anthropometric measurements and magnetic resonance imaging (MRI) measurements of the thigh in 149 healthy subjects (77 male, 72 female). LTL was measured using qPCR. Additionally, the subjects answered a questionnaire concerning their training behaviour.

RESULTS

In male subjects, LTL was significantly associated with thigh muscle mass, independent of age and body mass index (p=0.006). In addition, a slight association of LTL with weekly endurance units in the male group was found. These relations could not be observed in females.

CONCLUSIONS

In conclusion, we observed a sex-specific association of LTL and thigh muscle mass in healthy males. The reason of this sex-specific association is currently unclear, but could be related to different training effects and/or hormonal pathways in men and women.

Epicardial Adipose Tissue in Myocardial Disease: From Physiology to Heart Failure Phenotypes

Epicardial adipose tissue (EAT) is increasingly being recognized as a determinant of myocardial biology. The EAT-heart crosstalk suggests causal links between dysfunctional EAT and cardiomyocyte impairment. Obesity promotes EAT dysfunction and shifts in secreted adipokines which adversely affect cardiac metabolism, induce cardiomyocyte inflammation, redox imbalance and myocardial fibrosis. Thus, EAT determines cardiac phenotype via effects on cardiac energetics, contractility, diastolic function, and atrial conduction. Vice-versa the EAT is altered in heart failure (HF), and such phenotypic changes can be detected by noninvasive imaging or incorporated in Artificial Intelligence-enhanced tools to aid the diagnosis, subtyping or risk prognostication of HF. In the present article, we summarize the links between EAT and the heart, explaining how the study of epicardial adiposity can improve the understanding of cardiac disease, serve as a source of diagnostic and prognostic biomarkers, and as a potential therapeutic target in HF to improve clinical outcomes.

Sex Differences in Adiposity and Cardiovascular Diseases

Body fat distribution is a well-established predictor of adverse medical outcomes, independent of overall adiposity. Studying body fat distribution sheds insights into the causes of obesity and provides valuable information about the development of various comorbidities. Compared to total adiposity, body fat distribution is more closely associated with risks of cardiovascular diseases. The present review specifically focuses on the sexual dimorphism in body fat distribution, the biological clues, as well as the genetic traits that are distinct from overall obesity. Understanding the sex determinations on body fat distribution and adiposity will aid in the improvement of the prevention and treatment of cardiovascular diseases (CVD).

Investigation of the Relationship between the Mid_Thigh Adipose Tissue Distribution Measured by MRI and Serum Osteocalcin—A Sex-Based Approach

Osteocalcin, in its non-carboxylated form, has a positive effect on glucose metabolism. Additionally, osteocalcin levels are related to body composition, especially muscle mass. The relation to the distribution of different adipose tissue types, such as subcutaneous, intermuscular, and visceral adipose tissue, is unclear. This study aimed to investigate associations between serum osteocalcin and the distribution of subcutaneous and intermuscular adipose tissue of the mid-thigh. Furthermore, the influence of different training methods on osteocalcin levels was investigated. We performed adipose tissue quantification of subcutaneous adipose tissue (SAT) and intramuscular adipose tissue (IMAT) using MRI measurements of the mid-thigh in 128 volunteers (63 male/65 female). Laboratory analysis included blood lipid panel, serum insulin, adiponectin, and osteocalcin measurements. The main observation was a significant correlation of total serum osteocalcin (TOC) and the distribution of adipose tissue of the mid-thigh (SAT/(SAT + IMAT)) (cc = −0.29/p-value = 0.002), as well as the cross-sectional muscle area (MA), increasing with the weekly resistance training duration in males. Additionally, TOC (p-value = 0.01) and MA (p-value = 0.03) were negatively related to serum insulin. The significant relationship between TOC and SAT/(SAT + IMAT) is a new finding and confirms the negative influence of IMAT on glucose metabolism in a sex-specific approach. We could substantiate this by the negative relation of TOC with serum insulin.