Exercise Training Can Prevent Cardiac Hypertrophy Induced by Sympathetic Hyperactivity with Modulation of Kallikrein-Kinin Pathway and Angiogenesis

Sympathetic hyperactivity induces adverse effects in myocardial. Recent studies have shown that exercise training induces cardioprotection against sympathetic overload; however, relevant mechanisms of this issue remain unclear. We analyzed whether exercise can prevent pathological hypertrophy induced by sympathetic hyperactivity with modulation of the kallikrein-kinin and angiogenesis pathways. Male Wistar rats were assigned to non-trained group that received vehicle; non-trained isoproterenol treated group (Iso, 0.3 mg kg(-1) day(-1)); and trained group (Iso+Exe) which was subjected to sympathetic hyperactivity with isoproterenol. the Iso rats showed hypertrophy and myocardial dysfunction with reduced force development and relaxation of muscle. the isoproterenol induced severe fibrosis, apoptosis and reduced myocardial capillary. Interestingly, exercise blunted hypertrophy, myocardial dysfunction, fibrosis, apoptosis and capillary decreases. the sympathetic hyperactivity was associated with high abundance of ANF mRNA and beta-MHC mRNA, which was significantly attenuated by exercise. the tissue kallikrein was augmented in the Iso+Exe group, and kinin B-1 receptor mRNA was increased in the Iso group. Moreover, exercise induced an increase of kinin B-2 receptor mRNA in myocardial. the myocardial content of eNOS, VEGF, VEGF receptor 2, pAkt and Bcl-2 were increased in the Iso+Exe group. Likewise, increased expression of pro-apoptotic Bad in the Iso rats was prevented by prior exercise. Our results represent the first demonstration that exercise can modulate kallikrein-kinin and angiogenesis pathways in the myocardial on sympathetic hyperactivity. These findings suggest that kallikrein-kinin and angiogenesis may have a key role in protecting the heart.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)National Council for Scientific and TechnologicalUniv Nove Julho Uninove, Programa Posgrad Ciencias Reabilitacao, São Paulo, BrazilUniversidade Federal de São Paulo Unifesp, São Paulo, BrazilUniv São Paulo, São Paulo, BrazilUniv Nove Julho Uninove, Programa Posgrad Med, São Paulo, BrazilUniversidade Federal de São Paulo Unifesp, São Paulo, BrazilFAPESP: 2009/54225-8National Council for Scientific and Technological: 477458/2009-2National Council for Scientific and Technological: 479395/2012-8Web of Scienc

Amelioration of Cardiac Function and Activation of Anti-Inflammatory Vasoactive Peptides Expression in the Rat Myocardium by Low Level Laser Therapy

Low-level laser therapy (LLLT) has been used as an anti-inflammatory treatment in several disease conditions, even when inflammation is a secondary consequence, such as in myocardial infarction (MI). However, the mechanism by which LLLT is able to protect the remaining myocardium remains unclear. the present study tested the hypothesis that LLLT reduces inflammation after acute MI in female rats and ameliorates cardiac function. the potential participation of the Renin-Angiotensin System (RAS) and Kallikrein-Kinin System (KKS) vasoactive peptides was also evaluated. LLLT treatment effectively reduced MI size, attenuated the systolic dysfunction after MI, and decreased the myocardial mRNA expression of interleukin-1 beta and interleukin-6 in comparison to the non-irradiated rat tissue. in addition, LLLT treatment increased protein and mRNA levels of the Mas receptor, the mRNA expression of kinin B2 receptors and the circulating levels of plasma kallikrein compared to non-treated post-MI rats. On the other hand, the kinin B1 receptor mRNA expression decreased after LLLT. No significant changes were found in the expression of vascular endothelial growth factor (VEGF) in the myocardial remote area between laser-irradiated and non-irradiated post-MI rats. Capillaries density also remained similar between these two experimental groups. the mRNA expression of the inducible nitric oxide synthase (iNOS) was increased three days after MI, however, this effect was blunted by LLLT. Moreover, endothelial NOS mRNA content increased after LLLT. Plasma nitric oxide metabolites (NOx) concentration was increased three days after MI in non-treated rats and increased even further by LLLT treatment. Our data suggest that LLLT diminishes the acute inflammation in the myocardium, reduces infarct size and attenuates left ventricle dysfunction post-MI and increases vasoactive peptides expression and nitric oxide (NO) generation.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Nove Julho, UNINOVE, São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, São Paulo, BrazilUniv São Paulo, Heart Inst InCor, São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, São Paulo, BrazilCNPq: 477458/2009-2CNPq: 309715/2011-3CNPq: 479395/2012-8: 2009/54225-8Web of Scienc

Remodelamento Cardíaco e Expressão da ILK Diferem entre os Gêneros após Infarto do Miocárdio

Background: Gender can influence post-infarction cardiac remodeling. Objective: To evaluate whether gender influences left ventricular (LV) remodeling and integrin-linked kinase (ILK) after myocardial infarction (MI). Methods: Female and male Wistar rats were assigned to one of three groups: sham, moderate MI (size: 20-39% of LV area), and large MI (size: ≥40% of LV area). MI was induced by coronary occlusion, and echocardiographic analysis was performed after six weeks to evaluate MI size as well as LV morphology and function. Real-time RT-PCR and Western blot were used to quantify ILK in the myocardium. Results: MI size was similar between genders. MI resulted in systolic dysfunction and enlargement of end-diastolic as well as end-systolic dimension of LV as a function of necrotic area size in both genders. Female rats with large MI showed a lower diastolic and systolic dilatation than the respective male rats; however, LV dysfunction was similar between genders. Gene and protein levels of ILK were increased in female rats with moderate and large infarctions, but only male rats with large infarctions showed an altered ILK mRNA level. A negative linear correlation was evident between LV dimensions and ILK expression in female rats with large MI. Conclusions: Post-MI ILK expression is altered in a gender-specific manner, and higher ILK levels found in females may be sufficient to improve LV geometry but not LV function.Fundamento: O gênero pode ser decisivo no remodelamento cardíaco após infarto do miocárdio. Objetivo: Avaliar diferenças de gênero associadas ao remodelamento do ventrículo esquerdo (VE) após infarto do miocárdio (IM) e associadas à modulação de quinases acopladas à integrina (integrin-linked kinases-ILK). Métodos: Ratos Wistar machos e fêmeas foram divididos em 3 grupos: grupo sham, grupo com IM de extensão moderada (tamanho: 20-39% da área do VE); grupo com IM de grande extensão (tamanho: ≥ 40% da área do VE). O IM foi produzido por oclusão coronária e as análises ecocardiográficas foram obtidas após 6 semanas para avaliar a extensão do IM, bem como a morfologia e função do VE. RT-PCR em tempo real e Western blott foram realizados para quantificar a ILK no miocárdio. Resultados: A extensão do IM foi semelhante entre os gêneros. O IM resultou em disfunção sistólica e aumento do tamanho do VE no final da diástole e da sístole em função do tamanho da área necrótica para ambos os sexos. Ratos fêmeas com IM de grande extensão apresentaram dilatação diastólica e sistólica inferior a de ratos machos, mas a disfunção do VE foi semelhante em ambos os sexos. Os níveis gênicos e proteicos de ILK aumentaram em ratos fêmeas com infartos de extensão moderada e grande, mas apenas ratos machos com infartos de grande extensão apresentaram níveis alterados de mRNA do ILK. Uma correlação linear negativa foi observada entre as dimensões do VE e a expressão de ILK em ratos fêmeas com IM de grande extensão. Conclusões: A expressão de ILK pós-IM variou de maneira gênero-especifica, e os níveis mais elevados de ILK observados em fêmeas podem ser suficientes para melhorar a geometria do VE, mas não suficientes para melhorar a função do VE.FAPESPUniversidade Nove de Julho Programa de Pós-graduação em Ciências da ReabilitaçãoUniversidade Federal de São Paulo (UNIFESP) Departamento de CardiologiaUniversidade Federal de São Paulo (UNIFESP) Departamento de PatologiaUNIFESP, Depto. de CardiologiaUNIFESP, Depto. de PatologiaSciEL

Collagen content, capillary density and apoptosis are preserved in exercised rats on sympathetic hyperactivity.

<p>Panel <b>A–C</b>, Representative polarized light micrographs of tissue stained with picrosirius red (magnification 40×). Panel <b>D–E</b>, Representative electron micrographs for capillaries visualization (magnification 1650×). Panel <b>G–I</b>, TUNEL assay for cardiomyocytes in apoptosis (magnification: 20×) as estimated from cells marked in red (magnification 20×). Quantitative analysis for collagen content, capillary density and positive apoptotic cells are shown in panel <b>J</b>, <b>K</b> and <b>L</b>, respectively. Same letters above bars into graphs indicate values not different in ANOVA. Different letters above bars into graphs indicate significant difference between means.</p

Exercise modulates key components of the kallikrein-kinin pathway in the myocardial on sympathetic hyperactivity.

<p>A significantly up-regulation of gene (Panel <b>A</b>) and protein (Panel <b>B</b>) expression was detected in the trained rats submitted to isoproterenol injection. The kinin B₁ receptor gene was up-regulated in myocardial of sedentary isoproterenol-treated rats, whereas the exercised isoproterenol-treated rats the kinin B₁ receptor gene was normalized (Panel <b>C</b>). Moreover, exercise also increased kinin B₁ receptor in transcriptional level (Panel <b>D</b>). Same letters above bars into graphs indicate values not different in ANOVA. Different letters above bars into graphs indicate significant difference between means.</p

Effects of exercise training on the myocardial hypertrophy induced by sympathetic hyperactivity.

<p>Panel <b>A</b>, Body weight was evaluated at the end of study. Panel <b>B</b>, Absolute left ventricular (LV) mass of each experimental group. Panel <b>C</b>, LV mass was indexed by body weight of each animal. Panel <b>D</b>, Representative light micrographs of myocardial section stained with haematoxylin–eosin. Arrows indicate the cardiomyocyte nucleus on longitudinal orientation. The graph shows the results for nuclear volume of each experimental group. Panel <b>E</b>, Expression of hypertrophic mRNA markers for each experimental group determined by quantitative real-time RT-PCR. Same letters above bars into graphs indicate values not different in ANOVA. Different letters above bars into graphs indicate significant difference between means.</p

Histological changes and evaluation of capillaries density and VEGF levels of the remote myocardium after LLLT.

<p>Representative microphotographs of the remote myocardium stained with (<b>A</b>) Periodic acid-Schiff for capillary counting (400× original magnification, arrows indicate some capillaries). Parameters including capillarity (<b>B</b>), and myocardial VEGF levels (<b>C</b>) were evaluated in remote myocardial samples from experimental groups. Control, MI and MI+Laser groups were composed of 7, 12 and 14 rats, respectively for each evaluation. Data are means ± SEM. *p<0.05 <i>vs.</i> Control group. P values given were determined by ANOVA.</p

Rat primers used for Real-time PCR mRNA quantification.

<p>Rat primers used for Real-time PCR mRNA quantification.</p