Fat distribution and storage: how much, where, and how?

Asian Indian adolescents from Guadeloupe are fatter than their island counterparts

The present study aimed at comparing the anthropometric profile of Asian Indian adolescents from Guadeloupe with that of their island counterparts. A total of 720 voluntary 11- to 17-year-old students participated: 180 Asian Indians and 540 age- and sex-matched students of other origin. Weight and height were measured to calculate the BMI. Waist and hip circumferences and bicipital, tricipital, subscapular and supra-iliac skinfold thicknesses were assessed. The percentage of body fat was estimated by bioelectrical impedance analysis. Obesity was defined from BMI according to the International Obesity Task Force recommendations. Asian Indians were smaller and lighter than their counterparts. They had a higher body fat percentage even after adjustment on BMI but the prevalence of obesity did not differ, with an overall prevalence of 5·69 (95 % CI 5·67, 5·71) %. No principal effects of ethnicity on waist and hip circumferences or the waist:hip ratio were evidenced. The sum of the four skinfold thicknesses was the strongest predictor of body fat percentage, and the adjustment of overall body fat on subcutaneous fat cancelled the effect of ethnicity on this dependent variable. The present study found that Asian Indian adolescents from Guadeloupe had the same tendency toward higher body fat and body fat-for-BMI as previously documented in Asian Indian adults. It raises the hypothesis of a higher cardiovascular risk in this ethnic group from adolescence and questions the validity of using common BMI references for screening obesity in multiethnic communities.

Steatocholecystitis and fatty gallbladder disease

Obesity has become an epidemic worldwide. It is accompanied by a multitude of medical complications including metabolic syndrome. Obesity may lead to fatty infiltration of multiple internal organs including liver, heart, kidney, and pancreas, causing organ dysfunctions. Fatty infiltration leads to chronic inflammation and tissue damage. Fatty infiltration in the liver results in nonalcoholic fatty liver disease, which is increasingly common nowadays. Recent studies in animals and humans indicate that obesity also is associated with fatty infiltration of gallbladder, resulting in cholecystosteatosis. The increased gallbladder lipids include free fatty acids, phospholipids, and triglycerides. Enhanced inflammation with an increased amount of fat in the gallbladder results in an abnormal wall structure and decreased contractility. In support of this notion, a recent experiment on the effect of Ezetimibe, which is a novel drug that inhibits intestinal fat absorption, on fatty gallbladder disease reveals that Ezetimibe can ameliorate cholecystosteatosis and restore in vivo gallbladder contractility. The proportion of cholecystectomies performed for chronic acalculous cholecystitis has increased significantly over the past two decades. An increase in gallbladder fat, which leads to poor gallbladder emptying and biliary symptoms, may partly explain this phenomenon. Although dietary carbohydrates have been demonstrated to be associated with fatty gallbladder disease, other potential modifiable environmental factors are not clear. The pathogenesis and prognosis of fatty gallbladder disease, including steatocholecystitis, and the relations of fatty gallbladder disease to nonalcoholic fatty liver disease, including steatohepatitis, and other components of metabolic syndrome are largely unknown. More research is needed to answer these questions.

Effect of high-fat diet feeding on leptin receptor expression in white adipose tissue in rats: depot- and sex-related differential response

Previous studies have illustrated the importance of leptin receptor (OB-Rb) mediated action on adipocytes in the regulation of body weight. The aim of the present study was to investigate in male and female rats the effects of high-fat (HF) diet feeding on the expression levels of OB-Rb in different depots of white adipose tissue (WAT), and its relation to fatty acid oxidation capacity. Male and female Wistar rats were fed until the age of 6 months with a normal-fat (NF) or non-isocaloric HF-diet (10 and 45% calories from fat, respectively). At this age, the weight of three different fat depots (retroperitoneal, mesenteric and inguinal) and the expression levels of OB-Rb, PPARalpha and CPT1 in these depots were measured. HF-diet feeding resulted in an increase in the weight of the different fat depots, the retroperitoneal depot being the one with the greatest increase in both sexes. In this depot, HF-diet feeding resulted in a significant decrease in OB-Rb mRNA levels, more marked in male than in female rats. In the mesenteric depot, the effects of HF-diet feeding on OB-Rb mRNA levels were sex-dependent: they decreased in males rats (associated with a decrease in PPARalpha and CPT1 mRNA levels), but increased in female rats. In the inguinal depot, OB-Rb expression was not affected by HF-diet feeding. These results show that a chronic intake of an HF-diet altered the expression of OB-Rb in WAT in a depot and sex-dependent manner. The decreased expression of OB-Rb in the internal depots of male rats under HF-diet feeding, with the resulting decrease in leptin sensitivity, can help to explain the higher tendency of males to suffer from obesity-linked disorders under HF-diet conditions.

Should obesity be the main game? Or do we need an environmental makeover to combat the inflammatory and chronic disease epidemics?

There is a link between obesity and chronic disease. However, the causal relationship is complicated. Some forms of obesity are associated with low-level systemic inflammation, which is linked to disease. But lifestyle behaviours that may not necessarily cause obesity (poor diet, inadequate sleep, smoking, etc.) can independently cause inflammation and consequent disease. It is proposed here that it is the environment driving modern lifestyles, which is the true cause of much chronic disease, rather than obesity per se, and that obesity may be a marker of environmental derangement, rather than the primary cause of the problem. Attempts to clinically manage obesity alone on a large scale are therefore unlikely to be successful at the population level without significant lifestyle or environmental change. Environmental factors influencing obesity and health have now also been implicated in ecological perturbations such as climate change, through the shift to positive energy balance in humans caused by the exponential use of fossil fuels in such areas as transport, and consequent rises in carbon emissions into the atmosphere. It is proposed therefore that a more policy-based approach to dealing with obesity, which attacks the common causes of both biological and ecological 'dis-ease', could have positive effects on both chronic disease and environmental problems. A plea is thus made for a greater health input into discussions on environmental regulation for chronic disease control, as well as climate change.

Molecular inflammation: underpinnings of aging and age-related diseases

Recent scientific studies have advanced the notion of chronic inflammation as a major risk factor underlying aging and age-related diseases. In this review, low-grade, unresolved, molecular inflammation is described as an underlying mechanism of aging and age-related diseases, which may serve as a bridge between normal aging and age-related pathological processes. Accumulated data strongly suggest that continuous (chronic) upregulation of pro-inflammatory mediators (e.g., TNF-alpha, IL-1beta, IL-6, COX-2, iNOS) are induced during the aging process due to an age-related redox imbalance that activates many pro-inflammatory signaling pathways, including the NF-kappaB signaling pathway. These pro-inflammatory molecular events are discussed in relation to their role as basic mechanisms underlying aging and age-related diseases. Further, the anti-inflammatory actions of aging-retarding caloric restriction and exercise are reviewed. Thus, the purpose of this review is to describe the molecular roles of age-related physiological functional declines and the accompanying chronic diseases associated with aging. This new view on the role of molecular inflammation as a mechanism of aging and age-related pathogenesis can provide insights into potential interventions that may affect the aging process and reduce age-related diseases, thereby promoting healthy longevity.

Adipose tissue and skeletal muscle plasticity modulates metabolic health

Obesity, accumulation of adipose tissue, develops when energy intake exceeds energy expenditure. Adipose tissue is essential for buffering the differences between energy intake and expenditure by accumulating lipids while skeletal muscle is the energy burning machine. Here we adopted the concept that (i) adipose tissue ability to regulate the storage capacity for lipids as well as (ii) dynamic regulation of muscle and adipose tissue secretory and metabolic activity is important for maintaining the metabolic health. This might be at least in part related to tissue plasticity, a phenomenon enabling dynamic modulation of the tissue phenotype in different physiological and pathophysiological situations. Recent advances in our understanding of the complex endocrine function of adipose tissue in regulating lipid metabolism, adipogenesis, angiogenesis, extracellular matrix remodelling, inflammation and oxidative stress prompted us to review the role of tissue plasticity--dynamic changes in adipose tissue and skeletal muscle metabolic and endocrine phenotype--in determining the difference between metabolic health and disease.