The adipocyte as an endocrine cell:

Pleurotus Ostreatus Ameliorates Obesity by Modulating the Gut Microbiota in Obese Mice Induced by High-Fat Diet

Pleurotus ostreatus (PO), a common edible mushroom, contains rich nutritional components with medicinal properties. To explore the effect of PO on ameliorating obesity and modulating the gut microbiota, we administered the mice with a low-fat diet or high-fat diet containing different dosages of PO (mass fraction: 0%, 2.5%, 5% and 10%). The body weight, adipose tissue weight, GTT, ITT, blood lipids, serum biomarkers of liver/kidney function, the gut microbiota and function were measured and analyzed after 6 weeks of PO treatment. The results showed PO prevented obesity, maintained glucose homeostasis and beneficially modulated gut microbiota. PO modified the composition and functions of gut microbiota in obese mice and make them similar to those in lean mice, which contributed to weight loss. PO significantly increased the relative abundance of Oscillospira, Lactobacillus group and Bifidobacterium, while decreased the relative abundance of Bacteroides and Roseburia. The prediction of gut microbiota function showed PO upregulated lipid metabolism, carbohydrate metabolism, bile acid biosynthesis, while it downregulated adipocytokine signaling pathway and steroid hormone biosynthesis. Correlation analysis further suggested the potential relationship among obesity, gut microbiota and the function of gut microbiota. In conclusion, all the results indicated that PO ameliorated obesity at least partly by modulating the gut microbiota.

High-Speed Microdialysis-Capillary Electrophoresis Assays for Measuring Branched Chain Amino Acid Uptake in 3T3-L1 cells

We have developed a high-throughput microdialysis-capillary electrophoresis (MD-CE) assay for monitoring branched chain amino acid (BCAA) uptake/release dynamics in 3T3-L1 cells. BCAAs (i.e., isoleucine, leucine, and valine) and their downstream metabolites (i.e., alanine, glutamine, and glutamate) are important indicators of adipocyte lipogenesis. To perform an analysis, amino acids were sampled using microdialysis, fluorescently labeled in an online reaction, separated using CE, and detected using laser-induced fluorescence (LIF) in a sheath flow cuvette. Separation conditions were optimized for the resolution of the BCAAs isoleucine, leucine, and valine, as well as 13 other amino acids, including ornithine, alanine, glutamine, and glutamate. CE separations were performed in <30 s, and the temporal resolution of the online MD-CE assay was <60 s. Limits of detection (LOD) were 400, 200, and 100 nM for isoleucine, leucine, and valine, respectively. MD-CE dramatically improved throughput in comparison to traditional offline CE methods, allowing 8 replicates of 15 samples (i.e., 120 analyses) to be assayed in <120 min. The MD-CE assay was used to assess the metabolism dynamics of 3T3-L1 cells over time, confirming the utility of the assay.

J, Madruga VA, Chacon-Mikahil MPT. Efeito do treinamento concorrente nos componentes da síndrome metabólica de homens de meia-idade

INTRODUÇÃO: A prática regular de exercícios físicos é considerada fundamental para prevenção e tratamento da Síndrome Metabólica, porém pouco se sabe sobre a forma ideal de treinamento. OBJETIVO: Verificar o efeito de 16 semanas de treinamento concorrente (TC) com frequência semanal e duração da sessão similar ao treinamento de força (TF) e treinamento aeróbio (TA) isolados sobre os componentes da síndrome metabólica (SM) de homens de meia-idade. MÉTODOS: Foram selecionados 42 homens clinicamente saudáveis distribuídos em quatro grupos: TA (n = 13), TF (n = 9), TC (n = 10) e grupo controle (GC, n = 10). Os treinamentos foram compostos por duas etapas (E1 e E2) com duração de oito semanas cada, e frequência de três sessões/semana (TF: dez exercícios com 3 x 8-10 RM; TA: 60 min. de caminhada ou corrida a 55-85% VO2pico; TC: seis exercícios com 3 x 8-10 RM, seguidos de 30 min. de caminhada ou corrida a 55-85% VO2pico). Foram avaliadas circunferência de cintura (CC), perfil lipídico, glicose, pressão arterial (PA) e força máxima e VO2pico. RESULTADOS: A CC reduziu para o TA (-1,70%; p = 0,023) e TC (-1,66%; p = 0,018) e o LDL para o TF (-25,03%; p = 0,047) e TC (29,74%; p = 0,011). O TC promoveu redução na PA sistólica (-7,83%; p = 0,029). A força máxima e VO2pico aumentaram para os três grupos de treinamento (p > 0,05). CONCLUSÃO: A realização do TC frequência semanal e duração das sessões similar ao TA e TF isolados é mais eficaz para a melhora de componentes da SM.

The effects of soy isoflavone on insulin sensitivity and adipocytokines in insulin resistant rats administered with high-fat diet

The effects of soy isoflavone (SIF) on insulin sensitivity and adipocytokines in high-fat-diet-induced insulin resistant (IR) rats were studied. Male Sprague Dawley rats (n = 80) were randomly assigned into a basal diet fed group and high-fat diet fed group. The high-fat-diet-induced IR rats were assigned into IR model control group and three SIF-treated groups with different dosages. Thirty days later, the fasting blood glucose, insulin and adipocytokines in serum and mRNA expressions of adipocytokines in perirenal white adipose tissue were measured. The Homeostasis Model Assessment of IR was calculated. The administration of 450 mg kg(-1) d(-1) SIF decreased the body weights and depositions of visceral adipose tissue as well as improved insulin resistance in high-fat-diet-induced IR rats. The mechanisms were associated with SIF regulating the expression of adipocytokines, including adiponectin, leptin, resistin and TNF-alpha. SIF supplements may have favourable effects on insulin resistance in high-fat-diet-induced IR rats.

[The adipose tissue as a regulatory center of the metabolism]

The recent progress in the research about the metabolic properties of the adipose tissue and the discovery of its ability to produce hormones that are very active in pathophysiologic as well as physiologic processes is rebuilding the concepts about its biology. Its involvement in conditions like obesity, type 2 diabetes mellitus, arterial hypertension, arteriosclerosis, dislipidemias and chronic and acute inflammatory processes indicate that the understanding of its functional capacities may contribute to improve the prognosis of those diseases whose prevalence increased in a preoccupying manner. Here we review some functional aspects of adipocytes, such as the metabolism, its influence on energy homeostasis, its endocrine ability and the adipogenesis, i.e., the potential of pre-adipocytes present in adipose tissue stroma to differentiate into new adipocytes and regenerate the tissue. In addition, we are including some studies on the relationship between the adipose tissue and the pineal gland, a new and poorly known, although, as will be seen, very promising aspect of adipocyte physiology together with its possible favorable repercussions to the therapy of the obesity related diseases.

Les lipodystrophies secondaires aux traitements antirétroviraux de l’infection par le VIH

HIV infection requires the continuous administration of antiretroviral molecules. Individual molecules belonging to the two main classes, protease inhibitors (PIs) and nucleoside analogues inhibitors of the viral reverse transcriptase (NRTIs) have been shown to be involved in deleterious side effects collectively called the lipodystrophy syndrome. This syndrome associates altered body fat repartition (peripheral lipoatrophy and visceral fat hypertrophy) and metabolic alterations (dyslipidemia, insulin resistance and diabetes). The pathophysiology of these alterations is complex but different studies argue for adipose tissue being a target of some PIs and NRTIs acting through different mechanisms. NRTIs are able to induce mitochondrial dysfonction and to modify adipocyte phenotype and adipose tissue pattern of secretion of cytokines (TNFalpha, IL-6) and other adipokines (adiponectin, leptin) probably through the production of reactive oxygen species. Some PIs also act on adipocyte, alter its differentiation and insulin sensitivity and also the pattern of secretion of adipokines by adipose tissue. These hypotheses could explain the loss of adipose tissue, while the mechanisms of visceral fat hypertrophy remain speculative. Since some adipokines and the free fatty acids released by adipocytes play a major role in the control of liver and muscles insulin sensitivity, these alterations are probably involved in the metabolic alterations seen in the patients. In addition, lipodystrophic adipose tissue could be involved in the increased lesions of atherogenesis and steatohepatitis presented by these patients. The treatment of lipodystrophy remains difficult and, at present, privileges the switch of the more deleterious drugs towards new molecules less aggressive for adipose tissue.

[Visceral, subcutaneous or intramuscular fat: where is the problem?]

The adipose tissue is a dynamic organ that secrets several factors, denominated adipokines. They are associated, directly or indirectly, in a process that contributes to atherosclerosis, hypertension, insulinic resistance and diabetes type 2, dyslipidemias, presenting the link between adiposity, metabolic syndrome and cardiovascular diseases. In the obesity, body fat depots are increased, presenting eventual elevation in the adipokines expression and secretion. The different fat depots, visceral, abdominal subcutaneous, gluteal-femoral subcutaneous and intramuscular adipose tissue, have different metabolic and endocrine degrees, interfering, therefore, with specific form in the process associated with body adiposity in obese and diabetics subjects. The present study seeks to discuss the endocrine and metabolic role of each adipose tissue compartment, by way to assess their contribution to the complications linked to obesity.