Intergenerational inheritance induced by a high-fat diet causes hyperphagia and reduced hypothalamic sensitivity to insulin and leptin in the second-generation of rats.

OBJECTIVE: The aim was to investigate the intergenerational inheritance induced by a high-fat diet on sensitivity to insulin and leptin in the hypothalamic control of satiety in second-generation offspring, which were fed a control diet. METHODS: Progenitor rats were fed a high-fat or a control diet for 59 d until weaning. The first-generation and second-generation offspring were fed the control diet until 90 d of age. Body mass and adiposity index of the progenitors fed the high-fat diet and the second-generation offspring from progenitors fed the high-fat diet were evaluated as were the gene expression of DNA methyltransferase 3a, angiotensin-converting enzyme type 2, angiotensin II type 2 receptor, insulin and leptin signaling pathway (insulin receptor, leptin receptor, insulin receptor substrate 2, protein kinase B, signal transducer and transcriptional activator 3, pro-opiomelanocortin, and neuropeptide Agouti-related protein), superoxide dismutase activity, and the concentration of carbonyl protein and satiety-regulating neuropeptides, pro-opiomelanocortin and neuropeptide Agouti-related protein, in the hypothalamus. RESULTS: The progenitor group fed a high-fat diet showed increased insulin resistance and reduced insulin-secreting beta-cell function and reduced food intake, without changes in caloric intake. The second-generation offspring from progenitors fed a high-fat diet, compared with second-generation offspring from progenitors fed a control diet group, had decreased insulin-secreting beta-cell function and increased food and caloric intake, insulin resistance, body mass, and adiposity index. Furthermore, second-generation offspring from progenitors fed a high-fat diet had increased DNA methyltransferase 3a, neuropeptide Agouti-related protein, angiotensin II type 1 receptor, and nicotinamide adenine dinucleotide phosphate oxidase p47phox gene expression, superoxide dismutase activity, and neuropeptide Agouti-related protein concentration in the hypothalamus. In addition, there were reduced in gene expression of the insulin receptor, leptin receptor, insulin receptor substrate 2, pro-opiomelanocortin, angiotensin II type 2 receptor, angiotensin-converting enzyme type 2, and angiotensin-(1-7) receptor and pro-opiomelanocortin concentration in the second-generation offspring from progenitors fed the high-fat diet. CONCLUSIONS: Overall, progenitors fed a high-fat diet induced changes in the hypothalamic control of satiety of the second-generation offspring from progenitors fed the high-fat diet through intergenerational inheritance. These changes led to hyperphagia, alterations in the hypothalamic pathways of insulin, and leptin and adiposity index increase, favoring the occurrence of different cardiometabolic disorders in the second-generation offspring from progenitors fed the high-fat diet fed only with the control diet.

Progenitor with cardiometabolic disorders increases food intake, systemic inflammation and gut microbiota alterations in the second-generation offspring.

This work presents the effects of the high-fat diet (H) consumed by the progenitor (G0) on cardiometabolic disorders and intestinal microbiota in the second-generation offspring (F2). The rats submitted to H (G0H) or control (C) (G0C) diets, during mating, gestation and lactation, generated F2 offspring (F2-G0H and F2-G0C, respectively), which received only the C diet. Both, G0H and F2-G0H, showed changes in the intestinal microbiota, increased MAP, plasma TAG levels, adiposity index and the inflammatory process in retroperitoneal fat and in the colon shown by increased TNF-α, MCP-1, MyD88 and CAV-1 gene expression. In addition, F2-G0H showed increased food intake, leptin resistance, total cholesterol and plasma levels of MCP-1 and reduced adiponectin. Regarding microbial communities, a greater diversity was observed in 5 unique families of bacteria that was correlated with cardiometabolic disorders. Overall, progenitors with cardiometabolic disorders induce an increase in food intake, systemic inflammation and microbiota alterations in the F2-G0H offspring.

Different reactive species modulate the hypotensive effect triggered by angiotensins at CVLM of 2K1C hypertensive rats.

Hypertension is associated with increased central activity of the renin-angiotensin system (RAS) and oxidative stress. Here, we evaluated whether reactive species and neurotransmitters could contribute to the hypotensive effect induced by angiotensin (Ang) II and Ang-(1-7) at the caudal ventrolateral medulla (CVLM) in renovascular hypertensive rats (2K1C). Therefore, we investigated the effect of Ang II, Ang-(1-7), and the Ang-(1-7) antagonist A-779 microinjected before and after CVLM microinjection of the nitric oxide (NO)-synthase inhibitor, (L-NAME), vitamin C (Vit C), bicuculline, or kynurenic acid in 2K1C and SHAM rats. Baseline values of the mean arterial pressure (MAP) in 2K1C rats were higher than in SHAM rats. CVLM microinjection of Ang II, Ang-(1-7), l-NAME, or bicuculline induced decreases in the MAP in SHAM and 2K1C rats. In addition, Vit C and A-779 produced decreases in the MAP only in 2K1C rats. Kynurenic acid increased the MAP in both SHAM and 2K1C rats. Only the Ang-(1-7) effect was increased by l-NAME and reduced by bicuculline in SHAM rats. L-NAME also reduced the A-779 effect in 2K1C rats. Only the Ang II effect was abolished by CVLM Vit C and enhanced by CVLM kynurenic acid in SHAM and 2K1C rats. Overall, the superoxide anion and glutamate participated in the hypotensive effect of Ang II, while NO and GABA participated in the hypotensive effect of Ang-(1-7) in CVLM. The higher hypotensive response of A-779 in the CVLM of 2K1C rats suggests that Ang-(1-7) contributes to renovascular hypertension.

The Novel Angiotensin-(1-7) Analog, A-1317, Improves Insulin Resistance by Restoring Pancreatic ß-Cell Functionality in Rats With Metabolic Syndrome.

In previous studies we have shown that oral Ang-(1-7) has a beneficial therapeutic effect on cardiometabolic disturbances present in metabolic syndrome (MetS). Based on the fact that Ang-(1-7) acts through release of nitric oxide (NO), a new peptide, A-1317 was engineered adding the amino acid L-Arginine, the NO precursor, to the N-terminal portion of the Ang-(1-7). Therefore, in a single molecule the substrate and the activator of NO are combined. In the present study, we evaluated the effect of A-1317 oral treatment on liver-glucose metabolism in MetS induced by high fat (HF) diet in rats. Rats were subjected to control (AIN-93M, CT) or HF diets for 15 weeks to induce MetS and treated with A-1317, Ang-(1-7) included into hydroxypropyl-ß-cyclodextrin (HPßCD) or empty HPßCD (E), in the last 7 weeks. At the end of 15 weeks, hemodynamic, biometric, and biochemical parameters, redox process, and qRT-PCR gene expression of NO synthase and RAS components were evaluated in the liver. HF/E rats increased body mass gain, adiposity index, despite the reduction in food intake, increased plasma leptin, total cholesterol, triglycerides, ALT, fasting blood glucose, OGTT and insulin, HOMA-IR and MAP and HR. Furthermore, the MetS rats presented increased in liver angiotensinogen, AT1R, ACE mRNA gene expression and concentration of MDA and carbonylated protein. Both Ang-(1-7) and A-1317 oral treatment in MetS rats reverted most of these alterations. However, A-1317 was more efficient in reducing body mass gain, ALT, AST, total cholesterol, insulin, fasting blood glucose, ameliorating ß cell capacity by increasing HOMA-ß and QUICKI, whereas Ang-(1-7) reduced HOMA-ß and QUICKI. In addition, Ang-(1-7) increased Mas and AKT liver mRNA gene expression, while A-1317 increased both Mas and MRGD and AMPK liver mRNA gene expression, suggesting a distinct pathway of action of Ang-(1-7) and A-1317 in MetS rats. Taken together, our data showed that treatment with A-1317 was able to ameliorate MetS disorders and suggested that this effect was mainly via MRGD via activation of AMPK and increasing ß cell function.

Fitness is improved by adjustments in muscle intracellular signaling in rats with renovascular hypertension 2K1C undergoing voluntary physical exercise.

AIM: To evaluate physical fitness and cardiovascular effects in rats with renovascular hypertension, two kidneys, one clip (2K1C) submitted to voluntary exercise (ExV). MAIN METHODS: 24 h after surgery (SHAM and 2K1C) rats were submitted to ExV for one week (adaptation). ExV adherent rats were separated into exercise (2K1C-EX and SHAM-EX) or sedentary (2K1C-SED and SHAM-SED) groups. After 4 weeks, exhaustion test, plasma lactate, cardiovascular parameters were evaluated and gastrocnemius muscle was removed for evaluation of gene expression of muscle metabolism markers (PGC1α; AMPK, SIRT-1, UCP-3; MCP-1; LDH) and of the redox process. KEY FINDINGS: ExV decreased blood lactate concentration and increased SOD and CAT activity and a SIRT-1 and UCP-3 gene expression in the gastrocnemius muscle of 2K1C-ExV rats compared to 2K1C-SED rats. Gene expressions of PGC1α, UCP-3, MCT-1, AMPK were higher in 2K1C-ExV rats compared to SHAM-SED rats. Blood pressure in 2K1C-ExV was lower compared to 2K1C-SED and higher in SHAM-SED rats. Reflex bradycardia in 2K1C-EX rats increased compared to 2K1C-SED and was similar to SHAM-SED. The variation in mean blood pressure induced by ganglion blocker hexamethonium and Ang II AT1 receptor antagonist, losartan in the 2K1C-ExV rats was smaller compared to the 2K1C-SED rats and it was similar to the SHAM-SED rats. SIGNIFICANCE: O ExV induced adaptive responses in 2K1C-ExV rats by decreasing sympathetic and Ang II activities and stimulating intracellular signaling that favors redox balance and reduced blood lactate concentration. These adaptive responses, then, contribute to reduced arterial pressure, improved baroreflex sensitivity and physical fitness of 2K1C rats.

Maternal high-fat diet triggers metabolic syndrome disorders that are transferred to first and second offspring generations.

A high-fat (H) diet increases metabolic disorders in offspring. However, there is great variability in the literature regarding the time of exposure, composition of the H diets offered to the genitors and/or offspring and parameters evaluated. Here, we investigated the effect of a H diet subjected to the genitors on different cardio-metabolic parameters on first (F1)- and second (F2)-generation offspring. Female Fischer rats, during mating, gestation and breast-feeding, were subjected to the H diet (G0HF) or control (G0CF) diets. Part of F1 offspring becomes G1 genitors for generating the F2 offspring. After weaning, F1 and F2 rats consumed only the C diet. Nutritional, biometric, biochemical and haemodynamic parameters were evaluated. G0HF genitors had a reduction in food intake but energy intake was similar to the control group. Compared with the control group, the F1H and F2H offspring presented increased plasma leptin, insulin and fasting glucose levels, dietary intake, energy intake, adiposity index, mean arterial pressure, sympathetic drive evidenced by the hexamethonium and insulin resistance. Our data showed that only during mating, gestation and breast-feeding, maternal H diet induced cardio-metabolic disorders characteristic of human metabolic syndrome that were transferred to both females and males of F1 and F2 offspring, even if they were fed control diet after weaning. This process probably occurs due to the disturbance in mechanisms related to leptin that increases energy intake in F1H and F2H offspring. The present data reinforce the importance of balanced diet during pregnancy and breast-feeding for the health of the F1 and F2 offspring.

Antioxidant Effects of Oral Ang-(1-7) Restore Insulin Pathway and RAS Components Ameliorating Cardiometabolic Disturbances in Rats.

In prevention studies of metabolic syndrome (MetS), Ang-(1-7) has shown to improve the insulin signaling. We evaluated the HPßCD/Ang-(1-7) treatment on lipid metabolism, renin-angiotensin system (RAS) components, oxidative stress, and insulin pathway in the liver and gastrocnemius muscle and hepatic steatosis in rats with established MetS. After 7 weeks of high-fat (FAT) or control (CT) diets, rats were treated with cyclodextrin (HPßCD) or HPßCD/Ang-(1-7) in the last 6 weeks. FAT-HPßCD/empty rats showed increased adiposity index and body mass, gene expression of ACE/ANG II/AT1R axis, and oxidative stress. These results were accompanied by imbalances in the insulin pathway, worsening of liver function, hyperglycemia, and dyslipidemia. Oral HPßCD/Ang-(1-7) treatment decreased ACE and AT1R, increased ACE2 gene expression in the liver, and restored thiobarbituric acid reactive substances (TBARS), catalase (CAT), superoxide dismutase (SOD), insulin receptor substrate (Irs-1), glucose transporter type 4 (GLUT4), and serine/threonine kinase 2 (AKT-2) gene expression in the liver and gastrocnemius muscle improving hepatic function, cholesterol levels, and hyperglycemia in MetS rats. Overall, HPßCD/Ang-(1-7) treatment restored the RAS components, oxidative stress, and insulin signaling in the liver and gastrocnemius muscle contributing to the establishment of blood glucose and lipid homeostasis in MetS rats.

Oral Ang-(1-7) treatment improves white adipose tissue remodeling and hypertension in rats with metabolic syndrome.

OBJECTIVE: Angiotensin (Ang)-(1-7) has preventive effects on metabolic syndrome (MetS). The aim of this study was to evaluate the therapeutic effect of oral Ang-(1-7) on mean arterial pressure (MAP), insulin resistance (IR), inflammatory process, and remodeling of white adipose tissue (WAT) in rats with established MetS. METHODS: Rats were subjected to control (CT; AIN-93M) or high-fat (HF) diets for 13 wk to induce MetS and treated with Ang-(1-7) or vehicle (V) for the last 6 wk. At the end of 13 wk, MAP, biochemical and histological parameters, and uncoupling protein (UCP) and inflammatory gene expression were determined by quantitative reverse transcription polymerase chain reaction. RESULTS: HF-V rats showed increased visceral fat deposition, inflammatory cytokine expression, hyperplasia, and hypertrophy in retroperitoneal (WAT) and brown adipose tissue (BAT). Additionally, the gastrocnemius muscle reduced UCP-3 and increased the UCP-1 expression in BAT. HF-V also elevated levels of plasma insulin, glucose, homeostatic model assessment (HOMA) of IR and HOMA-ß, and increased body mass, adiposity, and MAP. Ang-(1-7) treatment in rats with MetS [HF-Ang-(1-7)] reduced WAT area, number of adipocytes, and expression of proinflammatory adipokines in WAT and BAT and increased UCP-3 in gastrocnemius muscle and UCP-1 expression in BAT compared with the HF-V group. These events prevented body mass gain, reduced adiposity, and normalized fasting plasma glucose, insulin levels, HOMA-IR, HOMA-ß, and MAP. CONCLUSION: Data from the present study demonstrated that oral Ang-(1-7) treatment is effective in restoring biochemical parameters and hypertension in established MetS by improving hypertrophy and hyperplasia in WAT and inflammation in adipose tissue, and regulating metabolic processes in the gastrocnemius muscle and BAT.

Physical training improves thermogenesis and insulin pathway, and induces remodeling in white and brown adipose tissues.

Physical training (PT) has been considered as a treatment in metabolic syndrome (MS), since it induces thermogenic activity in brown (BAT) and white (WAT) adipose tissues. We evaluated the therapeutic effect of PT on activity of WAT and BAT in rats with MS induced by high-fat diet (30% lard) for 13 weeks and submitted, for the last 6 weeks, to swimming or kept sedentary (SED) rats. MS-SED rats compared to control diet (CT-SED) rats showed low physical fitness and high levels of glucose, insulin, homeostasis evaluation of insulin resistance (HOMA-IR), homeostasis evaluation of the functional capacity of ß-cells (HOMA-ß), and blood pressure. The gastrocnemius muscle decreased in peroxisome proliferator-activated receptor gamma coactivator 1-alpha and beta (PGC-1α, PGC-1ß), and uncoupled protein 2 and 3 (UCP2 and UCP3) expressions. Both WAT and BAT increased in the adipocyte area and decreased in blood vessels and fibroblast numbers. WAT increased in expression of pro-inflammatory adipokines and decreased in anti-inflammatory adipokine and adiponectin. WAT and gastrocnemius showed impairment in the insulin signaling pathway. In response to PT, MS rats showed increased physical fitness and restoration of certain biometric and biochemical parameters and blood pressure. PT also induced thermogenic modulations in skeletal muscle, WAT and BAT, and also improved the insulin signaling pathway. Collectively, PT was effective in treating MS by inducing improvement in physical fitness and interchangeable effects between skeletal muscle, WAT and BAT, suggesting a development of brown-like adipocyte cells.

Swimming training induces liver adaptations to oxidative stress and insulin sensitivity in rats submitted to high-fat diet.

Oxidative stress, physical inactivity and high-fat (FAT) diets are associated with hepatic disorders such as metabolic syndrome (MS). The therapeutic effects of physical training (PT) were evaluated in rats with MS induced by FAT diet for 13 weeks, on oxidative stress and insulin signaling in the liver, during the last 6 weeks. FAT-sedentary (SED) rats increased body mass, retroperitoneal fat, mean arterial pressure (MAP) and heart rate (HR), and total cholesterol, serum alanine aminotransferase, glucose and insulin. Livers of FAT-SED rats increased superoxide dismutase activity, thiobarbituric acid-reactive substances, protein carbonyl and oxidized glutathione (GSSG); and decreased catalase activity, reduced glutathione/GSSG ratio, and the mRNA expression of insulin receptor substrate 1 (IRS-1) and serine/threonine kinase 2. FAT-PT rats improved in fitness and reduced their body mass, retroperitoneal fat, and glucose, insulin, total cholesterol, MAP and HR; and their livers increased superoxide dismutase and catalase activities, the reduced glutathione/GSSG ratio and the expression of peroxisome proliferator-activated receptor gamma and insulin receptor compared to FAT-SED rats. These findings indicated adaptive responses to PT by restoring the oxidative balance and insulin signaling in the liver and certain biometric and biochemical parameters as well as MAP in MS rats.