Brown adipose tissue (BAT) plays a key role in energy expenditure through its specialized thermogenic function. Therefore, BAT activation may help prevent and/or treat obesity. Interestingly, subcutaneous white adipose tissue (WAT) also has the ability to differentiate into brown-like adipocytes and may potentially contribute to increased thermogenesis. We have previously reported that eicosapentaenoic acid (EPA) reduces high-fat (HF)-diet-induced obesity and insulin resistance in mice. Whether BAT mediates some of these beneficial effects of EPA has not been determined. We hypothesized that EPA activates BAT thermogenic program, contributing to its antiobesity effects. BAT and WAT were harvested from B6 male mice fed HF diets supplemented with or without EPA. HIB 1B clonal brown adipocytes treated with or without EPA were also used. Gene and protein expressions were measured in adipose tissues and H1B 1B cells by quantitative polymerase chain reaction and immunoblotting, respectively. Our results show that BAT from EPA-supplemented mice expressed significantly higher levels of thermogenic genes such as PRDM16 and PGC1α and higher levels of uncoupling protein 1 compared to HF-fed mice. By contrast, both WATs (subcutaneous and visceral) had undetectable levels of these markers with no up regulation by EPA. HIB 1B cells treated with EPA showed significantly higher mRNA expression of PGC1α and SIRT2. EPA treatment significantly increased maximum oxidative and peak glycolytic metabolism in H1B 1B cells. Our results demonstrate a novel and promising role for EPA in preventing obesity via activation of BAT, adding to its known beneficial anti-inflammatory effects.
Scope
Obesity prevalence continues to increase and contribute to metabolic diseases, potentially by driving systemic inflammation. Curcumin is an anti‐inflammatory spice with claimed health benefits. However, mechanisms by which curcumin may reduce obesity‐associated inflammation are poorly understood; thus, it is hypothesized that benefits of curcumin consumption may occur through reduced white adipose tissue (WAT) inflammation and/or beneficial changes in gut bacteria.
Methods and Results
Male B6 mice are fed high‐fat diets (HFD, 45% kcal fat) or HFD supplemented with 0.4% (w/w) curcumin (HFC) for 14 weeks. Curcumin supplementation significantly reduces adiposity and total macrophage infiltration in WAT, compared to HFD group, consistent with reduced mRNA levels of M1 (Cd80, Cd38, Cd11c) and M2 (Arginase‐1) macrophage markers. Moreover, curcumin supplementation reduces expression of other key pro‐inflammatory genes, such as NF‐κB p65 subunit (p65), Stat1, Tlr4, and Il6, in WAT (p < 0.05). Using microbial 16S RNA sequencing, it is demonstrated that the relative abundance of the Lactococcus, Parasutterella, and Turicibacter genera are increased in the HFC group versus HFD.
Conclusions
Curcumin exerts protective metabolic effects in dietary obesity, in part through downregulation of adipose tissue inflammation, which may be mediated by alterations in composition of gut microbiota, and metabolism of curcumin into curcumin‐O‐glucuronide.
Effective dissolution of cellulosic macromolecules is the first predominant step to prepare functional bio-based materials with desirable properties. In this study, we developed an improved dissolution process using a freeze-drying pretreatment to promote the dissolution of cellulose. Rheological measurements of cellulose solutions and physicochemical characterization of regenerated cellulose films (scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis) were performed. Cellulose solution prepared from 5% microcrystalline cellulose (w:v) in the solvent exhibits a Newtonian fluid character while cellulose solutions at higher concentrations show a pseudo-plastic fluid behavior. Results from physicochemical characterization indicate that a freeze-drying pretreatment step of cellulose leads to a complete dissolution at 5% concentration while only part of cellulose is dissolved at 10% and 15% concentrations. The results obtained indicated that the use of a freeze-drying pretreatment step under mild conditions lead to a complete dissolution of cellulose at 5% concentration. The cellulose films prepared from 5% concentration exhibited desirable properties such as good optical transparency, crystallinity, and thermal stability.
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