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Brown Adipose Crosstalk in Tissue Plasticity and Human Metabolism.
Scheele, C, Wolfrum, C
Endocrine reviews. 2020;41(1)
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Plain language summary
Brown adipose tissue (BAT) is an important contributor to the regulation of metabolism via cellular communication with organs such as liver, muscle, gut and central nervous system. BAT is important for heat generation and is at high levels in human infants. Levels of activation of BAT decline as we age and it has been shown that the amount of BAT is smaller and its activity reduced in those with obesity and type 2 diabetes. To date, there is no answer to efficiently restore functional BAT in aging and obese subjects. This review looks at experiments done on the factors secreted from active BAT (batokines). The review aims to provide a structure for the processes and cell types involved in BAT and the recent findings of BAT whole-body communication are discussed. Altogether, these findings demonstrate that BAT has an adaptive capacity. Studying batokines, offers an alternative approach to identify novel drug targets for metabolic regulation.
Abstract
Infants rely on brown adipose tissue (BAT) as a primary source of thermogenesis. In some adult humans, residuals of brown adipose tissue are adjacent to the central nervous system and acute activation increases metabolic rate. Brown adipose tissue (BAT) recruitment occurs during cold acclimation and includes secretion of factors, known as batokines, which target several different cell types within BAT, and promote adipogenesis, angiogenesis, immune cell interactions, and neurite outgrowth. All these processes seem to act in concert to promote an adapted BAT. Recent studies have also provided exciting data on whole body metabolic regulation with a broad spectrum of mechanisms involving BAT crosstalk with liver, skeletal muscle, and gut as well as the central nervous system. These widespread interactions might reflect the property of BAT of switching between an active thermogenic state where energy is highly consumed and drained from the circulation, and the passive thermoneutral state, where energy consumption is turned off. (Endocrine Reviews 41: XXX - XXX, 2020).
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Cashew apple juice supplementation enhances leukocyte count by reducing oxidative stress after high-intensity exercise in trained and untrained men.
Prasertsri, P, Roengrit, T, Kanpetta, Y, Tong-Un, T, Muchimapura, S, Wattanathorn, J, Leelayuwat, N
Journal of the International Society of Sports Nutrition. 2019;16(1):31
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High-intensity aerobic training has been shown to suppress leukocyte counts in moderately fit athletes. The aim of this study to explore possible advantageous effects of cashew apple juice (CAJ) supplementation, and, if present, to identify the possible mechanisms underlying those effects. The study is a double-blind randomised cross-over design with two treatment arms: CAJ supplementation and placebo. Ten moderately (endurance) trained and untrained men were randomized to one of the two groups for four weeks, with a four-week wash out period. Results showed that CAJ supplementation for four weeks increased leukocyte (a type of blood cell) counts, while simultaneously decreasing oxidative stress, following an acute bout of high-intensity exercise in trained men. Furthermore, the CAJ supplementation increased neutrophil (a type of white blood cell) counts while simultaneously reducing oxidative stress and stress hormone concentrations in untrained men. The antioxidant effects following exercise were observed in both endurance-trained and untrained men. Authors conclude that CAJ supplementation is beneficial to men, both in resting states and in response to an acute bout of high-intensity aerobic exercise.
Abstract
BACKGROUND Cashew apple juice (CAJ) was shown to improve immunological mechanisms by regulating a balance between reactive oxygen species and antioxidant concentrations. However, no study exploring the effects of the CAJ and training status on the immune system and oxidative stress induced by exercise. Therefore, we investigated the effects of CAJ supplementation primarily on leukocyte counts and secondary on oxidative stress and cortisol changes after high-intensity exercise in trained and untrained men. METHODS Ten moderately (endurance) trained (Age = 21.5 ± 0.97 yr., VO2max = 45.6 ± 4.12 mL/kgBM/min) and ten sedentary men (Age = 20.4 ± 2.72 yr., VO2peak = 32.2 ± 7.26 mL/kgBM/min) were randomized to ingest either daily CAJ or a placebo at 3.5 mL/kgBM/day for 4 weeks, with a four-week washout period. Before and after each period, they performed 20-min, high-intensity cycling (85% VO2max), with blood samples collected immediately preceding and the following exercise. Samples were analyzed to determine leukocyte counts, malondialdehyde, 8-isoprostane, and cortisol concentrations. A repeated measures analysis of variance was used to examine the effects of supplement and training status over time with an alpha level of 0.05. RESULTS There was no interaction between supplement and training status on those variables before and after exercise. However, CAJ raised resting neutrophil counts and exercise-induced leukocyte counts in the trained group (all p < 0.05). Besides, CAJ significantly reduced plasma malondialdehyde concentrations at rest and after exercise and reduced the post-exercise plasma 8-isoprostane concentration in both groups of subjects (p < 0.05). Moreover, CAJ reduced plasma cortisol after exercise in the untrained subjects. CONCLUSIONS We suggest that 4-week CAJ supplementation can enhance exercise-induced leukocyte and resting neutrophil counts in trained men. The possible mechanism is a reduction in oxidative stress. However, the supplementation did not change the immune responses of untrained men, but it did reduce stress hormone concentrations. TRIAL REGISTRATION NUMBER TCTR20181127002 Registered 26 November 2018 "retrospectively registered".