Isocaloric intake of a high-fat diet modifies adiposity and lipid handling in a sex dependent manner in rats

<p>Abstract</p> <p>Background</p> <p>High-fat (HF) diet feeding usually leads to hyperphagia and body weight gain, but macronutrient proportions in the diet can modulate energy intake and fat deposition. The mechanisms of fat accumulation and mobilization may differ significantly between depots, and gender can also influence these differences.</p> <p>Aim</p> <p>To investigate, in rats of both sexes, the effect of an isocaloric intake of a diet with an unbalanced proportion of macronutrients on fatty acid composition of visceral and subcutaneous adipose tissues and how this is influenced by both dietary fatty acids and levels of proteins involved in tissue lipid handling.</p> <p>Methods</p> <p>Eight-week-old Wistar rats of both sexes were fed a control diet (3% <it>w/w </it>fat) or high-fat diet (30% <it>w/w </it>fat) for 14 weeks. Fatty acid composition was analyzed by gas-chromatography and levels of LPL, HSL, α2-AR, β3-AR, PKA and CPT1 were determined by Western blot.</p> <p>Results</p> <p>The HF diet did not induce hyperphagia or body weight gain, but promoted an increase of adiposity index only in male rats. HF diet produced an increase of the proportion of MUFA and a decrease in that of PUFA in both adipose depots and in both sexes. The levels of proteins involved in the adrenergic control of the lipolytic pathway increased in the gonadal fat of HF females, whereas LPL levels increased in the inguinal fat of HF males and decreased in that of females.</p> <p>Conclusion</p> <p>Sexual dimorphism in adiposity index reflects a differential sex response to dietary fatty acid content and could be related to the levels of the proteins involved in tissue lipid management.</p

Long-term high-fat-diet feeding induces skeletal muscle mitochondrial biogenesis in rats in a sex-dependent and muscle-type specific manner

<p>Abstract</p> <p>Background</p> <p>Mitochondrial dysfunction is thought to play a crucial role in the etiology of insulin resistance, in which skeletal muscle is the main tissue contributor. Sex differences in skeletal muscle insulin and antioxidant responses to high-fat-diet (HFD) feeding have been described. The aim of this study was to elucidate whether there is a sex dimorphism in the effects of HFD feeding on skeletal muscle mitochondrial biogenesis and on the adiponectin signaling pathway, as well as the influence of the muscle type (oxidative or glycolytic).</p> <p>Methods</p> <p>Gastrocnemius and soleus muscles of male and female Wistar rats of 2 months of age fed with a high-fat-diet (HFD) or a low fat diet for 26 weeks were used. Mitochondrial biogenesis and oxidative damage markers, oxidative capacity and antioxidant defences were analyzed. Serum insulin sensitivity parameters and the levels of proteins involved in adiponectin signaling pathway were also determined.</p> <p>Results</p> <p>HFD feeding induced mitochondrial biogenesis in both sexes, but to a higher degree in male rats. Although HFD female rats showed greater antioxidant protection and maintained a better insulin sensitivity profile than their male counterparts, both sexes showed an impaired response to adiponectin, which was more evident in gastrocnemius muscle.</p> <p>Conclusions</p> <p>We conclude that HFD rats may induce skeletal muscle mitochondrial biogenesis as an attempt to compensate the deleterious consequences of adiponectin and insulin resistance on oxidative metabolism, and that the effects of HFD feeding are sex-dependent and muscle-type specific.</p

GPER and ERα mediate estradiol enhancement of mitochondrial function in inflamed adipocytes through a PKA dependent mechanism.

Obesity is associated with inflammation, dysregulated adipokine secretion, and disrupted adipose tissue mitochondrial function. Estradiol (E2) has been previously reported to increase mitochondrial function and biogenesis in several cell lines, but neither the type of oestrogen receptor (ERα, ERβ and GPER) involved nor the mechanism whereby such effects are exerted have been fully described. Considering the anti-inflammatory activity of E2 as well as its effects in enhancing mitochondrial biogenesis, the aim of this study was to investigate the contribution of ERα, ERβ, and GPER signaling to the E2-mediated enhancement of adipocyte mitochondrial function in a pro-inflammatory situation. 3T3-L1 cells were treated for 24 h with ER agonists (PPT, DPN, and G1) and antagonists (MPP, PHTPP, and G15) in the presence or absence of interleukin 6 (IL6), as a pro-inflammatory stimulus. Inflammation, mitochondrial function and biogenesis markers were analyzed. To confirm the involvement of the PKA pathway, cells were treated with a GPER agonist, a PKA inhibitor, and IL6. Mitochondrial function markers were analyzed. Our results showed that activation of ERα and GPER, but not ERβ, was able to counteract the proinflammatory effects of IL6 treatment, as well as mitochondrial biogenesis and function indicators. Inhibition of PKA prevented the E2- and G1-associated increase in mitochondrial function markers. In conclusion E2 prevents IL6 induced inflammation in adipocytes and promotes mitochondrial function through the combined activation of both GPER and ERα. These findings expand our understanding of ER interactions under inflammatory conditions in female rodent white adipose tissue

Huellas de la Memoria

Camila Gianotti, Juan Martín Dabezies (eds.).[ES] Huellas de la Memoria recoge las diferentes miradas sobre el paisaje cultural rural de Tacuarembó, Uruguay. Paisaje entendido como una construcción social e histórica, como huella de la memoria pasada y presente. Es una obra con un fuerte componente gráfico y multivocal, en la que convergen en igualdad la percepción y opinión de diversos grupos, pobladores locales y agentes sociales.[EN] Huellas de la Memoria depicts the different visions of the rural cultural landscape of Tacuarembó, Uruguay. Landscape is understood as a social and historical construction, as traces of past and present memory. It is a multivocal work with a strong graphic component which includes the perception and opinion of various groups, local residents and social agents.Publicación autofinanciada por el Incipit.-- Trabajo realizado dentro del proyecto "El paisaje arqueológico de las Tierras bajas". Un modelo de gestión integral del Patrimonio arqueológico de Uruguay. Financiado por la Dirección General de Bellas Artes y Bienes Culturales (2005 – 2009), Ministerio de Cultura (España).Peer reviewe