Cardiac Remodeling in Obesity-Resistance Model is not Related to Collagen I and III Protein Expression

Abstract Background: As some individuals present resistance to obesity development, experiments have been trying to understand their susceptibility to cardiometabolic diseases. Objetive: To evaluate if the cardiac remodeling was related to collagen protein expression change. Methods: Male Wistar rats were randomized into two experimental groups: control diet (CD, n=15) or high-fat diet (HFD, n=15) for 30 weeks. Rats fed with HFD were ranked based on their adiposity indexes and classified as obese (Ob, n = 8) or obesity-resistant (ROb, n = 6). Rats that failed to present the normal characteristic of the control group while fed with CD were excluded (Control, n = 8). Nutritional profile, comorbidities (dyslipidemia, hypertension, glucose metabolism, hyperleptinemia), cardiac remodeling, and collagen protein expression were evaluated. The groups were compared by One-Way ANOVA, together the Tukey post hoc test, with p<0.05 considered significant. Results: The Ob rats presented an increased adiposity index when compared to C and ROb. Both groups Ob and ROb presented increased low-density lipoprotein (LDL), insulin, homeostatic model assessment of insulin resistance (HOMA- IR) and systolic blood pressure (SBP), and low high-density lipoprotein (HDL) levels when compared to the control group. The levels of triglycerides, non-esterified fatty acid (NEFA), and leptin were lower in ROb as compared to Ob, but higher than the control group. The Ob and ROb groups presented cardiac remodeling, evidenced by echocardiographic and post-mortem analysis. The collagen protein expression did not differ among the groups. Conclusion: The ROb animals present cardiac remodeling that is not related to collagen type I and III protein expression change.

Relationship between Innate Immune Response Toll-Like Receptor 4 (TLR-4) and the Pathophysiological Process of Obesity Cardiomyopathy. / Relação entre Resposta Imune Inata do Receptor Toll-Like-4 (TLR-4) e o Processo Fisiopatológico da Cardiomiopatia da Obesidade.

BACKGROUND: Obesity is a chronic low-grade inflammation condition related to cardiac disorders. However, the mechanism responsible for obesity-related cardiac inflammation is unclear. The toll-like receptor 4 (TLR-4) belongs to a receptor of the transmembrane family responsible for the immune response whose activation stimulates the production of proinflammatory cytokines. OBJECTIVE: To test whether the activation of the TLR-4 receptor participates in the obesity cardiomyopathy process, due to cytokine production through NF-ĸB activation. METHODS: Male Wistar rats were randomized into two groups: the control group (C, n= 8 animals) that received standard diet/water and the obese group (OB, n= 8 animals) that were fed a high sugar-fat diet and water plus 25% of sucrose for 30 weeks. Nutritional analysis: body weight, adiposity index, food, water, and caloric intake. Obesity-related disorders analysis: plasma glucose, uric acid and triglycerides, HOMA-IR, systolic blood pressure, TNF-α in adipose tissue. Cardiac analysis included: TLR-4 and NF-ĸB protein expression, TNF-α and IL-6 levels. Comparison by unpaired Student's t-test or Mann- Whitney test with a p-value < 0.05 as statistically significant. RESULTS: The OB group showed obesity, high glucose, triglycerides, uric acid, HOMA, systolic blood pressure, and TNF-α in adipose tissue. OB group presented cardiac remodeling and diastolic dysfunction. TLR-4 and NF-ĸB expression and cytokine levels were higher in OB. CONCLUSION: Our findings conclude that, in an obesogenic condition, the inflammation derived from cardiac TLR-4 activation can be a mechanism able to lead to remodeling and cardiac dysfunction.

FUNDAMENTO: A obesidade é uma condição inflamatória crônica de baixo grau relacionada a distúrbios cardíacos. No entanto, o mecanismo responsável pela inflamação cardíaca relacionada à obesidade não é claro. O receptor do tipo toll 4 (TLR-4) pertence a um receptor da família das transmembranas, responsável pela resposta imune, cuja ativação estimula a produção de citocinas pró-inflamatórias. OBJETIVO: Testar se a ativação do receptor TLR-4 participa do processo de cardiomiopatia da obesidade, devido à produção de citocinas por meio da ativação do NF-ĸB. MÉTODOS: Ratos Wistar machos foram randomizados em dois grupos: o grupo controle (C, n = 8 animais) que recebeu dieta padrão/água e o grupo obeso (OB, n = 8 animais) que foi alimentado com dieta rica em açúcar e gordura e água mais 25% de sacarose por 30 semanas. Análise nutricional: peso corporal, índice de adiposidade, alimentos, água e ingestão calórica. Análise de distúrbios relacionados à obesidade: glicose plasmática, ácido úrico e triglicerídeos, HOMA-IR, pressão arterial sistólica, TNF-α no tecido adiposo. A análise cardíaca incluiu: expressão das proteínas TLR-4 e NF-ĸB, níveis de TNF-α e IL-6. Comparação pelo teste t de Student não pareado ou teste de Mann-Whitney com um valor de p <0,05 como estatisticamente significativo. RESULTADOS: O grupo OB apresentou obesidade, glicose elevada, triglicerídeos, ácido úrico, HOMA, pressão arterial sistólica e TNF-α no tecido adiposo. O grupo OB apresentou remodelação cardíaca e disfunção diastólica. A expressão de TLR-4 e NF-ĸB e os níveis de citocinas foram maiores em OB. CONCLUSÃO: Nossos achados concluem que, em uma condição obesogênica, a inflamação derivada da ativação do TLR-4 cardíaco pode ser um mecanismo capaz de levar à remodelação e disfunção cardíaca.

Relação entre resposta imune inata do receptor toll-like-4 (TLR-4) e o processo fisiopatológico da cardiomiopatia da obesidade / Relationship between innate immune response toll-like receptor 4 (TLR-4) and the pathophysiological process of obesity cardiomyopathy

Resumo Fundamento A obesidade é uma condição inflamatória crônica de baixo grau relacionada a distúrbios cardíacos. No entanto, o mecanismo responsável pela inflamação cardíaca relacionada à obesidade não é claro. O receptor do tipo toll 4 (TLR-4) pertence a um receptor da família das transmembranas, responsável pela resposta imune, cuja ativação estimula a produção de citocinas pró-inflamatórias. Objetivo Testar se a ativação do receptor TLR-4 participa do processo de cardiomiopatia da obesidade, devido à produção de citocinas por meio da ativação do NF-ĸB. Métodos Ratos Wistar machos foram randomizados em dois grupos: o grupo controle (C, n = 8 animais) que recebeu dieta padrão/água e o grupo obeso (OB, n = 8 animais) que foi alimentado com dieta rica em açúcar e gordura e água mais 25% de sacarose por 30 semanas. Análise nutricional: peso corporal, índice de adiposidade, alimentos, água e ingestão calórica. Análise de distúrbios relacionados à obesidade: glicose plasmática, ácido úrico e triglicerídeos, HOMA-IR, pressão arterial sistólica, TNF-α no tecido adiposo. A análise cardíaca incluiu: expressão das proteínas TLR-4 e NF-ĸB, níveis de TNF-α e IL-6. Comparação pelo teste t de Student não pareado ou teste de Mann-Whitney com um valor de p <0,05 como estatisticamente significativo. Resultados O grupo OB apresentou obesidade, glicose elevada, triglicerídeos, ácido úrico, HOMA, pressão arterial sistólica e TNF-α no tecido adiposo. O grupo OB apresentou remodelação cardíaca e disfunção diastólica. A expressão de TLR-4 e NF-ĸB e os níveis de citocinas foram maiores em OB. Conclusão Nossos achados concluem que, em uma condição obesogênica, a inflamação derivada da ativação do TLR-4 cardíaco pode ser um mecanismo capaz de levar à remodelação e disfunção cardíaca.

Abstract Background Obesity is a chronic low-grade inflammation condition related to cardiac disorders. However, the mechanism responsible for obesity-related cardiac inflammation is unclear. The toll-like receptor 4 (TLR-4) belongs to a receptor of the transmembrane family responsible for the immune response whose activation stimulates the production of proinflammatory cytokines. Objective To test whether the activation of the TLR-4 receptor participates in the obesity cardiomyopathy process, due to cytokine production through NF-ĸB activation. Methods Male Wistar rats were randomized into two groups: the control group (C, n= 8 animals) that received standard diet/water and the obese group (OB, n= 8 animals) that were fed a high sugar-fat diet and water plus 25% of sucrose for 30 weeks. Nutritional analysis: body weight, adiposity index, food, water, and caloric intake. Obesity-related disorders analysis: plasma glucose, uric acid and triglycerides, HOMA-IR, systolic blood pressure, TNF-α in adipose tissue. Cardiac analysis included: TLR-4 and NF-ĸB protein expression, TNF-α and IL-6 levels. Comparison by unpaired Student's t-test or Mann- Whitney test with a p-value < 0.05 as statistically significant. Results The OB group showed obesity, high glucose, triglycerides, uric acid, HOMA, systolic blood pressure, and TNF-α in adipose tissue. OB group presented cardiac remodeling and diastolic dysfunction. TLR-4 and NF-ĸB expression and cytokine levels were higher in OB. Conclusion Our findings conclude that, in an obesogenic condition, the inflammation derived from cardiac TLR-4 activation can be a mechanism able to lead to remodeling and cardiac dysfunction.

Tomato-Oleoresin Anti-Inflammatory Effect Recovers Obesity-Induced Cardiac Dysfunction by Modulating Myocardial Calcium Handling.

BACKGROUND/AIMS: Considering the importance of inflammation on obesity-related disorders pathogenesis, including cardiac dysfunction, the interest in natural anti-inflammatory therapeutic strategies has emerged. The lycopene is a carotenoid presents in tomato and red fruits that displays anti-inflammatory properties. In this sense, we will evaluate the anti-inflamma-tory effect of tomato-oleoresin supplementation on obesity- related cardiac dysfunction by modulating myocardial calcium kinetic. METHODS: Male Wistar rats were initially randomized into 2 experimental groups: (Control, n= 20) or high sugar- fat diet (HSF, n=20) for 20 weeks. At week 20th, once detected the cardiac dysfunction (cardiac remodeling, systolic and diastolic dysfunction) by echocardiography in HSF group, animals were randomly divided to begin the treatment with tomato-oleoresin, performing 4 groups: Control (n= 10); Control + tomato tomato-oleoresin supplementation (Control + Ly, n= 10); HSF (n= 10) or HSF + tomato tomato-oleoresin supplementation (HSF + Ly, n= 10). Tomato oleoresin was mixed with maize oil equivalent to 10mg lycopene/kg body weight (BW) per day and given orally, by gavage, every morning for a 10-week period. It was analyzed cardiac inflammatory parameters by the enzyme-linked immunosorbent assay (ELISA) and in vivo (echocardiography) and in vitro (studying isolated papillary muscles from the left ventricle) cardiac function. The groups were compared by Two-Way analysis of variance (ANOVA). RESULTS: The HSF diet induced cardiac dysfunction (FS(%) C: 60.4±1.3; C+Ly: 60.9±1.3; HSF: 51.7±1.3; HSF+Ly: 59.4±1.4) and inflammation (TNF-α: C:1.88±0.41; C+Ly: 1.93±1.01; HSF: 4.58±1.99; HSF+Ly: 2.03±0.55; IL-6: C:0.58±0.16; C+Ly: 0.40±0.16; HSF: 2.00±0.45; HSF+Ly: 0.53±0.26; MCP-1: C:0.31±0.08; C+Ly: 0.43±0.22; HSF: 1.54±0.32; HSF+Ly: 0.50±0.16). Tomato-oleoresin supplementation improved cardiac remodeling and dysfunction, cardiac inflammation and myocardial calcium kinetic. CONCLUSION: the anti-inflammatory effect of tomato-oleoresin supplementation treated the obesity-induced cardiac dysfunction by modulating myocardial calcium handling.

A Redução do Colágeno Tipo I está Associada ao Aumento da Atividade da Metaloproteinase-2 e da Expressão Proteica de Leptina no Miocárdio de Ratos Obesos / Decreased Collagen Type I is Associated with Increased Metalloproteinase-2 Activity and Protein Expression of Leptin in the Myocardium of Obese Rats

Resumo Fundamento A obesidade é um fator de risco para complicações médicas, incluindo o sistema cardiovascular. Há informações limitadas sobre o colágeno no coração obeso. Nosso estudo anterior demonstrou uma redução dos níveis proteicos de colágeno miocárdico tipo I em ratos obesos alimentados com uma dieta com alto teor de gordura durante 34 semanas. No entanto, os mecanismos responsáveis pelos níveis baixos não estão completamente elucidados. Objetivo O objetivo deste estudo foi testar a hipótese de que a redução do colágeno tipo I está associada ao aumento da atividade da metaloproteinase-2 (MMP-2), a qual está ligada à elevação de leptina no miocárdio de ratos obesos. Métodos Ratos Wistar machos com 30 dias de idade foram randomizados em dois grupos: controle (dieta padrão) e obeso (dieta com alto teor de gordura), e alimentados durante 34 semanas. Foram avaliados as características gerais dos animais e os perfis metabólicos e endócrinos. Foram avaliados as expressões proteicas miocárdicas de colágeno tipo I, leptina e inibidores teciduais de metaloproteinases (TIMP), bem como a atividade da MMP-2. O teste de correlação de Pearson foi aplicado para determinar as associações entre variáveis. O nível de significância foi de 5%. Resultados Os animais obesos apresentaram índice de adiposidade mais elevado em comparação ao controle. Foram observadas comorbidades como intolerância à glicose, hiperinsulinemia, resistência à insulina, hiperleptinemia e hipertensão nos ratos obesos. A obesidade reduziu o colágeno tipo I, TIMP-1 e TIMP-2, e aumentou a leptina e a MMP-2 no miocárdio. Houve uma correlação negativa entre o colágeno tipo I e a MMP-2 e uma correlação positiva entre a leptina e a MMP-2. Conclusão Foi confirmada a hipótese de que a redução do colágeno tipo I está associada ao aumento da atividade da MMP-2 e da expressão de leptina no miocárdio de ratos obesos. (Arq Bras Cardiol. 2020; 115(1):61-70)

Abstract Background Obesity is a risk factor for medical complications, including the cardiovascular system. There is limited information on collagen in the heart in obesity. Our previous study showed decreased protein levels of myocardial collagen type I in obese rats fed a high-fat diet for 34 weeks. However, the mechanisms responsible for low levels are not fully elucidated. Objective The purpose of this study was to test the hypothesis that the reduction in collagen type I is associated with increased metalloproteinase-2 (MMP-2) activity, which is linked to elevated leptin in the myocardium of obese rats. Methods Thirty-day-old male Wistar rats were randomized into two groups, control (standard diet) and obese (high-fat diet), and fed for 34 weeks. The general animal characteristics and metabolic and endocrine profiles were evaluated. Myocardial protein expressions of collagen I, leptin, tissue inhibitors of metalloproteinases (TIMP), and MMP-2 activity were assessed. Pearson correlation was employed to determine the associations between variables. The level of significance was 5%. Results The obese animals had increased adiposity index compared to control. Comorbidities such as glucose intolerance, hyperinsulinemia, insulin resistance, hyperleptinemia, and hypertension were observed in obese rats. Obesity reduced collagen I, TIMP-1, and TIMP-2, and it increased leptin and MMP-2 in the myocardium. There was a negative correlation between collagen I and MMP-2 and a positive correlation between leptin and MMP-2. Conclusion The hypothesis was confirmed; the reduction in collagen type I is associated with increased MMP-2 activity and leptin expression in the myocardium of obese rats. (Arq Bras Cardiol. 2020; 115(1):61-70)

Decreased Collagen Type I is Associated with Increased Metalloproteinase-2 Activity and Protein Expression of Leptin in the Myocardium of Obese Rats. / A Redução do Colágeno Tipo I está Associada ao Aumento da Atividade da Metaloproteinase-2 e da Expressão Proteica de Leptina no Miocárdio de Ratos Obesos.

Background Obesity is a risk factor for medical complications, including the cardiovascular system. There is limited information on collagen in the heart in obesity. Our previous study showed decreased protein levels of myocardial collagen type I in obese rats fed a high-fat diet for 34 weeks. However, the mechanisms responsible for low levels are not fully elucidated. Objective The purpose of this study was to test the hypothesis that the reduction in collagen type I is associated with increased metalloproteinase-2 (MMP-2) activity, which is linked to elevated leptin in the myocardium of obese rats. Methods Thirty-day-old male Wistar rats were randomized into two groups, control (standard diet) and obese (high-fat diet), and fed for 34 weeks. The general animal characteristics and metabolic and endocrine profiles were evaluated. Myocardial protein expressions of collagen I, leptin, tissue inhibitors of metalloproteinases (TIMP), and MMP-2 activity were assessed. Pearson correlation was employed to determine the associations between variables. The level of significance was 5%. Results The obese animals had increased adiposity index compared to control. Comorbidities such as glucose intolerance, hyperinsulinemia, insulin resistance, hyperleptinemia, and hypertension were observed in obese rats. Obesity reduced collagen I, TIMP-1, and TIMP-2, and it increased leptin and MMP-2 in the myocardium. There was a negative correlation between collagen I and MMP-2 and a positive correlation between leptin and MMP-2. Conclusion The hypothesis was confirmed; the reduction in collagen type I is associated with increased MMP-2 activity and leptin expression in the myocardium of obese rats. (Arq Bras Cardiol. 2020; 115(1):61-70).

Protective Effect of Tomato-Oleoresin Supplementation on Oxidative Injury Recoveries Cardiac Function by Improving ß-Adrenergic Response in a Diet-Obesity Induced Model.

The system redox imbalance is one of the pathways related to obesity-related cardiac dysfunction. Lycopene is considered one of the best antioxidants. The aim of this study was to test if the tomato-oleoresin would be able to recovery cardiac function by improving ß-adrenergic response due its antioxidant effect. A total of 40 animals were randomly divided into two experimental groups to receive either the control diet (Control, n = 20) or a high sugar-fat diet (HSF, n = 20) for 20 weeks. Once cardiac dysfunction was detected by echocardiogram in the HSF group, animals were re- divided to begin the treatment with Tomato-oleoresin or vehicle, performing four groups: Control (n = 6); (Control + Ly, n = 6); HSF (n = 6) and (HSF + Ly, n = 6). Tomato oleoresin (10 mg lycopene/kg body weight (BW) per day) was given orally every morning for a 10-week period. The analysis included nutritional and plasma biochemical parameters, systolic blood pressure, oxidative parameters in plasma, heart, and cardiac analyses in vivo and in vitro. A comparison among the groups was performed by two-way analysis of variance (ANOVA). Results: The HSF diet was able to induce obesity, insulin-resistance, cardiac dysfunction, and oxidative damage. However, the tomato-oleoresin supplementation improved insulin-resistance, cardiac remodeling, and dysfunction by improving the ß-adrenergic response. It is possible to conclude that tomato-oleoresin is able to reduce the oxidative damage by improving the system's ß-adrenergic response, thus recovering cardiac function.

Myocardial Dysfunction after Severe Food Restriction Is Linked to Changes in the Calcium-Handling Properties in Rats.

Severe food restriction (FR) impairs cardiac performance, although the causative mechanisms remain elusive. Since proteins associated with calcium handling may contribute to cardiac dysfunction, this study aimed to evaluate whether severe FR results in alterations in the expression and activity of Ca2+-handling proteins that contribute to impaired myocardial performance. Male 60-day-old Wistar-Kyoto rats were fed a control or restricted diet (50% reduction in the food consumed by the control group) for 90 days. Body weight, body fat pads, adiposity index, as well as the weights of the soleus muscle and lung, were obtained. Cardiac remodeling was assessed by morphological measures. The myocardial contractile performance was analyzed in isolated papillary muscles during the administration of extracellular Ca2+ and in the absence or presence of a sarcoplasmic reticulum Ca2+-ATPase (SERCA2a) specific blocker. The expression of Ca2+-handling regulatory proteins was analyzed via Western Blot. Severe FR resulted in a 50% decrease in body weight and adiposity measures. Cardiac morphometry was substantially altered, as heart weights were nearly twofold lower in FR rats. Papillary muscles isolated from FR hearts displayed mechanical dysfunction, including decreased developed tension and reduced contractility and relaxation. The administration of a SERCA2a blocker led to further decrements in contractile function in FR hearts, suggesting impaired SERCA2a activity. Moreover, the FR rats presented a lower expression of L-type Ca2+ channels. Therefore, myocardial dysfunction induced by severe food restriction is associated with changes in the calcium-handling properties in rats.

The influence of obesity by a diet high in saturated fats and carbohydrates balance in the manifestation of systemic complications and comorbidities

BACKGROUND: The aim of this study is to test the hypothesis that obesity induced by a diet rich in saturated fats and balanced in carbohydrates is associated with the development of systemic complications and comorbidities. METHODS: Thirty-seven 60-day-old male Wistar rats were randomized into two groups: control (C,n= 18, standard diet) and obese (OB, n= 19, high-saturated fat diet), for 33 weeks. Nutritional profile: food and caloric intake, feed efficiency, body weight, and adiposity index. Complications: in plasma were analyzed dyslipidemia, insulin resistance (HOMA-IR), glucose intolerance, hyperleptinemia, hyperinsulinemia, plasmatic C-reactive protein (CRP), interleukin-6(IL-6), and tumor necrosis factor-alpha (TNF-α); in the myocardial and epididymal adipose tissue were assessed IL-6and TNF-α. Comorbidities: diabetes mellitus and systemic blood pressure (SBP). Student'sttest, ANOVA, and Bonferroni P< 0.05.RESULTS:The final body weight, feed efficiency, and adiposity index were higher in OB group than in control; although food intake was lower in OB group, caloric intake was similar in both groups. Specific parameters, such as LDL, cholesterol, triglycerides, HOMA-IR, CRP, TNF-αin epididymal adipose tissue, and IL-6 in the myocardium, were higher in obese rats than in controls. SBP, baseline glucose, and glucose after 2 h of overload were significantly increased in OB group; however, the severity was not enough to classify the animals as diabetic and hypertensive. CONCLUSION: Obesity induced by a diet high in saturated fatty acids with balanced carbohydrates for 33 weeks in Wistar rats was effective in triggering complications but unable to develop comorbidities.

Cardiac, Metabolic and Molecular Profiles of Sedentary Rats in the Initial Moment of Obesity / Perfis Cardíaco, Metabólico e Molecular de Ratos Sedentários no Momento Inicial da Obesidade

Abstract Background: Different types of high-fat and/or high-energy diets have been used to induce obesity in rodents. However, few studies have reported on the effects observed at the initial stage of obesity induced by high-fat feeding on cardiac functional and structural remodelling. Objective: To characterize the initial moment of obesity and investigate both metabolic and cardiac parameters. In addition, the role of Ca2+ handling in short-term exposure to obesity was verified. Methods: Thirty-day-old male Wistar rats were randomized into two groups (n = 19 each): control (C; standard diet) and high-fat diet (HF, unsaturated high-fat diet). The initial moment of obesity was defined by weekly measurement of body weight (BW) complemented by adiposity index (AI). Cardiac remodelling was assessed by morphological, histological, echocardiographic and papillary muscle analysis. Ca2+ handling proteins were determined by Western Blot. Results: The initial moment of obesity occurred at the 3rd week. Compared with C rats, the HF rats had higher final BW (4%), body fat (20%), AI (14.5%), insulin levels (39.7%), leptin (62.4%) and low-density lipoprotein cholesterol (15.5%) but did not exhibit alterations in systolic blood pressure. Echocardiographic evaluation did not show alterations in cardiac parameters. In the HF group, muscles were observed to increase their +dT/dt (C: 52.6 ± 9.0 g/mm2/s and HF: 68.0 ± 17.0 g/mm2/s; p < 0.05). In addition, there was no changes in the cardiac expression of Ca2+ handling proteins. Conclusion: The initial moment of obesity promotes alterations to hormonal and lipid profiles without cardiac damage or changes in Ca2+ handling.

Resumo Fundamentos: Diferentes tipos de dietas hiperlipídicas e/ou hipercalóricas têm sido usados para induzir obesidade em roedores. No entanto, poucos estudos relataram os efeitos da obesidade induzida por dieta hiperlipídica em sua fase inicial sobre a remodelação cardíaca funcional e estrutural. Objetivo: Caracterizar o momento inicial da obesidade e investigar parâmetros metabólicos e cardíacos. Além disso, analisar o papel do trânsito de Ca+2 em curtos períodos de exposição à obesidade. Métodos: Ratos Wistar com idade de 30 dias foram distribuídos aleatoriamente em dois grupos (n = 19 em cada grupo): controle (C, dieta padrão) e dieta hiperlipídica (HL, dieta rica em gordura insaturada). O momento inicial da obesidade foi definido por medidas semanais do peso corporal, complementadas pelo índice de adiposidade (IA). A remodelação cardíaca foi avaliada por análise morfológica, histológica, ecocardiográfica e funcional dos músculos papilares. Proteínas envolvidas no trânsito de Ca2+ foram determinadas por Western Blot. Resultados: O momento inicial da obesidade ocorreu na terceira semana. Em comparação aos ratos C, os animais HL apresentaram maior peso corporal final (4%), gordura corporal (20%), IA (14,5%), níveis de insulina (39,7%), leptina (62,4%) e lipoproteína de baixa densidade (15,5%), mas não apresentaram alterações na pressão sistólica. A avaliação ecocardiográfica não mostrou alterações nos parâmetros cardíacos. No grupo HL, observou-se um aumento no +dT/dt (C: 52,6 ± 9,0 g/mm2/s e HL: 68,0 ± 17,0 g/mm2/s; p < 0,05) muscular. Além disso, não houve alterações na expressão cardíaca de proteínas envolvidas no trânsito de Ca2+. Conclusão: O momento inicial da obesidade promove alterações nos perfis hormonais e lipídicos sem causar danos cardíacos ou mudanças no trânsito de Ca2+.

Cardiac, Metabolic and Molecular Profiles of Sedentary Rats in the Initial Moment of Obesity.

BACKGROUND: Different types of high-fat and/or high-energy diets have been used to induce obesity in rodents. However, few studies have reported on the effects observed at the initial stage of obesity induced by high-fat feeding on cardiac functional and structural remodelling. OBJECTIVE: To characterize the initial moment of obesity and investigate both metabolic and cardiac parameters. In addition, the role of Ca2+ handling in short-term exposure to obesity was verified. METHODS: Thirty-day-old male Wistar rats were randomized into two groups (n = 19 each): control (C; standard diet) and high-fat diet (HF, unsaturated high-fat diet). The initial moment of obesity was defined by weekly measurement of body weight (BW) complemented by adiposity index (AI). Cardiac remodelling was assessed by morphological, histological, echocardiographic and papillary muscle analysis. Ca2+ handling proteins were determined by Western Blot. RESULTS: The initial moment of obesity occurred at the 3rd week. Compared with C rats, the HF rats had higher final BW (4%), body fat (20%), AI (14.5%), insulin levels (39.7%), leptin (62.4%) and low-density lipoprotein cholesterol (15.5%) but did not exhibit alterations in systolic blood pressure. Echocardiographic evaluation did not show alterations in cardiac parameters. In the HF group, muscles were observed to increase their +dT/dt (C: 52.6 ± 9.0 g/mm2/s and HF: 68.0 ± 17.0 g/mm2/s; p < 0.05). In addition, there was no changes in the cardiac expression of Ca2+ handling proteins. CONCLUSION: The initial moment of obesity promotes alterations to hormonal and lipid profiles without cardiac damage or changes in Ca2+ handling.

Renal inflammatory and oxidative and metabolic changes after 6 weeks of cafeteria diet in rats.

INTRODUCTION: Obesity is a disease in which inflammation is directly involved and can lead to impaired renal function. OBJECTIVE: To evaluate the influence of short term exposure to cafeteria diet on kidney tissue inflammation and advanced glycation end products (AGEs) in the rat plasma. METHODS: Male Wistar rats (10 weeks of age, weighing 350 g) were assigned to receive commercial chow diet (C; n = 8 animals/group, 5% of energy from fat) or cafeteria diet (CAF-D, n = 8 animals/group: 29% energy fat) and sucrose in drinking water (300 g/L) for 6 weeks. RESULTS: adiposity index at six weeks was higher in CAF-D group compared to C. The same behavior was observed for plasma levels of glucose, triglycerides, leptin, insulin and AGEs. The gene expression of IL-6 and TNF-α in renal tissue was higher in CAF-D group and no significant difference in adipose tissue. There was no increase of these cytokines in plasma and kidney or histologically. There was a significant decrease of adiponectin in the CAF-D group. CONCLUSION: The short exposure CAF-D reflects changes in metabolism, increased plasma levels of AGEs, which may reflect the increased expression of inflammatory cytokines in the kidney.

Inflamação renal, alterações metabólicas e oxidativas após 6 semanas de dieta de cafeteria em ratos / Renal inflammatory and oxidative and metabolic changes after 6 weeks of cafeteria diet in rats

Resumo Introdução: A obesidade é uma doença em que a inflamação está inteiramente envolvida e pode causar insuficiência renal. Objetivo: Avaliar a influência da exposição a curto prazo de uma dieta de cafeteria sobre a inflamação no tecido renal e a formação de produtos de glicação avançada (AGEs) no plasma de rato. Métodos: Ratos Wistar machos (10 semanas de idade, pesando 350 g) foram designados para receber dieta de ração comercial (C; n = 8 animais/grupo, 5% de energia a partir de gordura) ou dieta de cafeteria (CAF-D, n = 8 animais/grupo: 29% de energia de gordura) e de sacarose em água (300 g/L) de beber durante 6 semanas. Resultados: Índice de adiposidade em seis semanas foi maior no grupo CAF-D em comparação com C. O mesmo comportamento foi observado para os níveis plasmáticos de glicose, triglicerídeos, leptina, insulina e AGEs. A expressão do gene de IL-6 e TNF-α em tecido renal foi maior no grupo D-CAF e nenhuma diferença significativa no tecido adiposo. Não houve aumento destas citocinas no plasma ou rim. Houve uma diminuição significativa de adiponectina no grupo CAF-D. Conclusão: A exposição a curto prazo da CAF-D reflete alterações no metabolismo, aumento dos níveis plasmáticos de AGEs, o que pode refletir o aumento expressão de citocinas inflamatórias no rim.

Abstract Introduction: Obesity is a disease in which inflammation is directly involved and can lead to impaired renal function. Objective: To evaluate the influence of short term exposure to cafeteria diet on kidney tissue inflammation and advanced glycation end products (AGEs) in the rat plasma. Methods: Male Wistar rats (10 weeks of age, weighing 350 g) were assigned to receive commercial chow diet (C; n = 8 animals/group, 5% of energy from fat) or cafeteria diet (CAF-D, n = 8 animals/group: 29% energy fat) and sucrose in drinking water (300 g/L) for 6 weeks. Results: adiposity index at six weeks was higher in CAF-D group compared to C. The same behavior was observed for plasma levels of glucose, triglycerides, leptin, insulin and AGEs. The gene expression of IL-6 and TNF-α in renal tissue was higher in CAF-D group and no significant difference in adipose tissue. There was no increase of these cytokines in plasma and kidney or histologically. There was a significant decrease of adiponectin in the CAF-D group. Conclusion: The short exposure CAF-D reflects changes in metabolism, increased plasma levels of AGEs, which may reflect the increased expression of inflammatory cytokines in the kidney.

Multivariate analysis for animal selection in experimental research.

BACKGROUND: Several researchers seek methods for the selection of homogeneous groups of animals in experimental studies, a fact justified because homogeneity is an indispensable prerequisite for casualization of treatments. The lack of robust methods that comply with statistical and biological principles is the reason why researchers use empirical or subjective methods, influencing their results. OBJECTIVE: To develop a multivariate statistical model for the selection of a homogeneous group of animals for experimental research and to elaborate a computational package to use it. METHODS: The set of echocardiographic data of 115 male Wistar rats with supravalvular aortic stenosis (AoS) was used as an example of model development. Initially, the data were standardized, and became dimensionless. Then, the variance matrix of the set was submitted to principal components analysis (PCA), aiming at reducing the parametric space and at retaining the relevant variability. That technique established a new Cartesian system into which the animals were allocated, and finally the confidence region (ellipsoid) was built for the profile of the animals' homogeneous responses. The animals located inside the ellipsoid were considered as belonging to the homogeneous batch; those outside the ellipsoid were considered spurious. RESULTS: The PCA established eight descriptive axes that represented the accumulated variance of the data set in 88.71%. The allocation of the animals in the new system and the construction of the confidence region revealed six spurious animals as compared to the homogeneous batch of 109 animals. CONCLUSION: The biometric criterion presented proved to be effective, because it considers the animal as a whole, analyzing jointly all parameters measured, in addition to having a small discard rate.

Multivariate Analysis for Animal Selection in Experimental Research / Análise Multivariada na Seleção de Animais em Pesquisas Experimentais

Background: Several researchers seek methods for the selection of homogeneous groups of animals in experimental studies, a fact justified because homogeneity is an indispensable prerequisite for casualization of treatments. The lack of robust methods that comply with statistical and biological principles is the reason why researchers use empirical or subjective methods, influencing their results. Objective: To develop a multivariate statistical model for the selection of a homogeneous group of animals for experimental research and to elaborate a computational package to use it. Methods: The set of echocardiographic data of 115 male Wistar rats with supravalvular aortic stenosis (AoS) was used as an example of model development. Initially, the data were standardized, and became dimensionless. Then, the variance matrix of the set was submitted to principal components analysis (PCA), aiming at reducing the parametric space and at retaining the relevant variability. That technique established a new Cartesian system into which the animals were allocated, and finally the confidence region (ellipsoid) was built for the profile of the animals’ homogeneous responses. The animals located inside the ellipsoid were considered as belonging to the homogeneous batch; those outside the ellipsoid were considered spurious. Results: The PCA established eight descriptive axes that represented the accumulated variance of the data set in 88.71%. The allocation of the animals in the new system and the construction of the confidence region revealed six spurious animals as compared to the homogeneous batch of 109 animals. Conclusion: The biometric criterion presented proved to be effective, because it considers the animal as a whole, analyzing jointly all parameters measured, in addition to having a small discard rate. .

Fundamento: Muitos pesquisadores buscam métodos para a seleção de grupos homogêneos de animais em pesquisas experimentais, fato que se justifica por ser a homogeneidade pré-requisito indispensável à casualização de tratamentos. A ausência de métodos robustos, que atendam a princípios estatísticos e biológicos, faz com que os pesquisadores utilizem métodos empíricos ou subjetivos, influenciando seus resultados. Objetivo: Desenvolver modelo estatístico multivariado para a seleção de grupo homogêneo de animais para pesquisas experimentais e elaborar pacote computacional que o operacionalize. Métodos: O conjunto de dados ecocardiográficos de 115 ratos Wistar, machos, com estenose aórtica (EAo) supravalvular foi utilizado para exemplificar o desenvolvimento do modelo. Inicialmente, os dados foram padronizados, tornando-se adimensionais. Em sequência, submeteu-se a matriz de variabilidade do conjunto à análise de componentes principais (ACP) buscando-se reduzir o espaço paramétrico e conservar a variabilidade relevante. Essa técnica estabeleceu um novo sistema cartesiano em que os animais foram alocados e, finalmente, construiu-se a região de confiança (elipsoide) para o perfil de respostas homogêneas dos animais. Os que se situaram no interior do elipsoide foram considerados pertencentes ao grupo homogêneo; caso contrário, espúrios ao grupo. Resultados: A ACP estabeleceu oito eixos descritores que representaram a variabilidade acumulada dos dados em 88,71%. A alocação dos animais no novo sistema e a construção da região de confiança revelou a presença de seis espúrios ao lote homogêneo formado por 109 animais. Conclusão: O critério biométrico proposto mostra-se eficiente, pois considera o animal como um todo, analisando conjuntamente todos os parâmetros mensurados, além de apresentar pequena frequência de descartes. .

Obesity preserves myocardial function during blockade of the glycolytic pathway.

BACKGROUND: Obesity is defined by excessive accumulation of body fat relative to lean tissue. Studies during the last few years indicate that cardiac function in obese animals may be preserved, increased or diminished. OBJECTIVE: Study the energy balance of the myocardium with the hypothesis that the increase in fatty acid oxidation and reduced glucose leads to cardiac dysfunction in obesity. METHODS: 30-day-old male Wistar rats were fed standard and hypercaloric diet for 30 weeks. Cardiac function and morphology were assessed. In this paper was viewed the general characteristics and comorbities associated to obesity. The structure cardiac was determined by weights of the heart and left ventricle (LV). Myocardial function was evaluated by studying isolated papillary muscles from the LV, under the baseline condition and after inotropic and lusitropic maneuvers: myocardial stiffness; postrest contraction; increase in extracellular Ca2+ concentration; change in heart rate and inhibitor of glycolytic pathway. RESULTS: Compared with control group, the obese rats had increased body fat and co-morbities associated with obesity. Functional assessment after blocking iodoacetate shows no difference in the linear regression of DT, however, the RT showed a statistically significant difference in behavior between the control and the obese group, most notable being the slope in group C. CONCLUSION: The energy imbalance on obesity did not cause cardiac dysfunction. On the contrary, the prioritization of fatty acids utilization provides protection to cardiac muscle during the inhibition of glycolysis, suggesting that this pathway is fewer used by obese cardiac muscle.

Obesity Preserves Myocardial Function During Blockade of the Glycolytic Pathway / A Obesidade Preserva a Função do Miocárdio Durante o Bloqueio da Via Glicolítica

Background: Obesity is defined by excessive accumulation of body fat relative to lean tissue. Studies during the last few years indicate that cardiac function in obese animals may be preserved, increased or diminished. Objective: Study the energy balance of the myocardium with the hypothesis that the increase in fatty acid oxidation and reduced glucose leads to cardiac dysfunction in obesity. Methods: 30-day-old male Wistar rats were fed standard and hypercaloric diet for 30 weeks. Cardiac function and morphology were assessed. In this paper was viewed the general characteristics and comorbities associated to obesity. The structure cardiac was determined by weights of the heart and left ventricle (LV). Myocardial function was evaluated by studying isolated papillary muscles from the LV, under the baseline condition and after inotropic and lusitropic maneuvers: myocardial stiffness; postrest contraction; increase in extracellular Ca2+ concentration; change in heart rate and inhibitor of glycolytic pathway. Results: Compared with control group, the obese rats had increased body fat and co-morbities associated with obesity. Functional assessment after blocking iodoacetate shows no difference in the linear regression of DT, however, the RT showed a statistically significant difference in behavior between the control and the obese group, most notable being the slope in group C. Conclusion: The energy imbalance on obesity did not cause cardiac dysfunction. On the contrary, the prioritization of fatty acids utilization provides protection to cardiac muscle during the inhibition of glycolysis, suggesting that this pathway is fewer used by obese cardiac muscle. .

Fundamento: A obesidade é definida por um acúmulo excessivo do tecido adiposo em relação a massa magra tecidual. Estudos realizados nos últimos anos sugerem que a função cardíaca em animais obesos pode se encontrar preservada, aumentada ou reduzida. Objetivo: Estudar o balanço energético do miocárdio com a hipótese de que o aumento na oxidação de ácidos graxos e redução de glicose levam à disfunção cardíaca na obesidade. Métodos: Ratos Wistar machos com 30 dias de idade foram alimentados com uma dieta padrão ou hipercalórica durante 30 semanas. A função e morfologia cardíacas foram analisadas. Neste trabalho foram estudadas as características gerais e comorbidades associadas com a obesidade. A estrutura cardíaca foi determinada pelo peso do coração e do ventrículo esquerdo (VE). A função do miocárdio foi avaliada pela análise de músculos papilares isolados do VE, na condição basal e depois de manobras inotrópicas e lusitrópicas: rigidez do miocárdio, contração pós-pausa, aumento da concentração extracelular de Ca2+, mudança na frequência de estímulos e inibição da via glicolítica. Resultados: Os ratos obesos tiveram um aumento de tecido adiposo e comorbidades associadas à obesidade em relação aos ratos do grupo controle. A análise funcional após o bloqueio pelo iodoacetato não mostrou diferença na regressão linear da tensão desenvolvida (TD), entretanto, a tensão de repouso (TR) apresentou uma diferença estatística significativa entre o grupo controle e o grupo obeso, mais notadamente na inclinação da curva no grupo C. Conclusão: O desequilíbrio energético na obesidade não promoveu ...

Influence of term of exposure to high-fat diet-induced obesity on myocardial collagen type I and III.

BACKGROUND: Obesity is a risk factor for many medical complications; medical research has shown that hemodynamic, morphological and functional abnormalities are correlated with the duration and severity of obesity. OBJECTIVE: Present study determined the influence of term of exposure to high-fat diet-induced obesity on myocardial collagen type I and III. METHODS: Thirty-day-old male Wistar rats were randomly distributed into two groups: a control (C) group fed a standard rat chow and an obese (Ob) group alternately fed one of four palatable high-fat diets. Each diet was changed daily, and the rats were maintained on their respective diets for 15 (C15 and Ob15) and 30 (C30 and Ob30) consecutive weeks. Obesity was determined by adiposity index. RESULTS: The Ob15 group was similar to the C15 group regarding the expression of myocardial collagen type I; however, expression in the Ob30 group was less than C30 group. The time of exposure to obesity was associated with a reduction in collagen type I in Ob30 when compared with Ob15. Obesity did not affect collagen type III expression. CONCLUSION: This study showed that the time of exposure to obesity for 30 weeks induced by unsaturated high-fat diet caused a reduction in myocardial collagen type I expression in the obese rats. However, no effect was seen on myocardial collagen type III expression.

Influencia do tempo de exposicao a obesidade induzida por dieta hiperlipidica sobre os colagenos tipo I e III miocardico / Influence of Term of Exposure to High-Fat Diet-Induced Obesity on Myocardial Collagen Type I and III

FUNDAMENTO: A obesidade é um fator de risco para muitas complicações médicas; a pesquisa médica demonstrou que as alterações hemodinâmicas, morfológicas e funcionais estão correlacionadas com a duração e gravidade da obesidade. OBJETIVO: O presente estudo determinou a influência do tempo de exposição à obesidade induzida por dieta com alto teor de gordura no colágenos tipo I e III miocárdico. MÉTODOS: Ratos machos com trinta dias de idade, da raça Wistar, foram distribuídos aleatoriamente em dois grupos: um grupo de controle (C) alimentado com ração padrão e um grupo de ratos obesos (Ob) alternadamente alimentados com uma de quatro dietas palatáveis ricas em gordura. Cada dieta foi mudada diariamente, e os ratos foram mantidos em suas respectivas dietas por 15 (C15 e Ob15) e 30 (C30 e Ob30) semanas consecutivas. A obesidade foi determinada pelo índice de adiposidade. RESULTADOS: O grupo Ob15 foi similar ao grupo C15 em relação à expressão de colágeno miocárdico tipo I; contudo, a expressão no grupo Ob30 foi menor do que no grupo C30. O tempo de exposição à obesidade foi associado com uma redução de colágeno do tipo I no grupo Ob30, quando comparado com o Ob15. A obesidade não afetou a expressão do colágeno tipo III. CONCLUSÃO: Este estudo mostrou que o tempo de exposição à obesidade por 30 semanas induzida por uma dieta rica em gordura insaturada causou uma redução na expressão do colágeno miocárdico tipo I em ratos obesos. No entanto, nenhum efeito foi observado em relação à expressão do colágeno miocárdico tipo III .

BACKGROUND: Obesity is a risk factor for many medical complications; medical research has shown that hemodynamic, morphological and functional abnormalities are correlated with the duration and severity of obesity. OBJECTIVE: Present study determined the influence of term of exposure to high-fat diet-induced obesity on myocardial collagen type I and III. METHODS: Thirty-day-old male Wistar rats were randomly distributed into two groups: a control (C) group fed a standard rat chow and an obese (Ob) group alternately fed one of four palatable high-fat diets. Each diet was changed daily, and the rats were maintained on their respective diets for 15 (C15 and Ob15) and 30 (C30 and Ob30) consecutive weeks. Obesity was determined by adiposity index. RESULTS: The Ob15 group was similar to the C15 group regarding the expression of myocardial collagen type I; however, expression in the Ob30 group was less than C30 group. The time of exposure to obesity was associated with a reduction in collagen type I in Ob30 when compared with Ob15. Obesity did not affect collagen type III expression. CONCLUSION: This study showed that the time of exposure to obesity for 30 weeks induced by unsaturated high-fat diet caused a reduction in myocardial collagen type I expression in the obese rats. However, no effect was seen on myocardial collagen type III expression. .

Influence of long-term obesity on myocardial gene expression.

BACKGROUND: Several authors have shown that deterioration of cardiac function is associated with the degree and duration of obesity. It is necessary to establish the gene expression patterns after prolonged periods of obesity. OBJECTIVE: This study tested the hypothesis that increased duration of exposure to obesity leads to a reduction in the mRNA levels of proteins involved in regulation of myocardial Ca2+ homeostasis. In addition, this study verified whether the decrease in mRNA expression was caused by a reduction in thyroid hormone. METHODS: Thirty-day-old male Wistar rats were distributed in two groups: control (C) and obese (Ob). The C group was fed a standard diet and the Ob was fed with high-fat diets for 15, 30 and 45 weeks. Obesity was defined by adiposity index. The gene expression was assessed by quantitative real-time PCR. RESULTS: The adiposity index was higher in the Ob compared to the C after all periods. While obesity at 15 and 45 weeks resulted in a reduction in mRNA of sarcoplasmic reticulum Ca2+- ATPase (SERCA2a), Na+/Ca2+ exchanger (NCX), and calsequestrin (CSQ), L-type Ca2+ channels, ryanodine receptor, SERCA2a, phospholamban (PLB), NCX, and CSQ expression were increased compared to the C after 30 weeks. There was no significant association between T3 levels and mRNA expression. CONCLUSIONS: Our data indicate that obesity over the short and long periods of time may promote alteration in gene expression of Ca2+ homeostasis regulatory proteins without influence by thyroid hormone.