Efeito do treinamento físico aeróbio no inotropismo miocárdico de ratos idosos

Exercise training effects on the contractility of aged myocardium have been investigated for more than 20 years, but the data are still unclear. This study evaluated the hypothesis that a swimming training (ST) may improve myocardial inotropism in older rats. Male Wistar rats aged 4 (young) and 21 (old) months-old were divided into young untrained (YNT), old untrained (ONT), and old trained (OTR; 6 weeks of ST) groups. Echocardiography and hemodynamic were employed to assess left ventricular morphology and function. Myocardial mechanics was evaluated on papillary muscles. Histological and immunoblotting were carried out to evaluate fibrosis and proteins that modulate the myocardial function and calcium handling. We found that older rats did not show cardiac dysfunction, but ONT group showed lower physical performance during a swimming test (YNT: 5 ± 2; ONT: −16 ± 0.4; OTR: 51 ± 3; Δ%, sec). Moreover, ONT group showed worse myocardial inotropism, in which it was reversed by ST (Peak developed tension: YNT: 6.2 ± 0.7; ONT: 3.9 ± 0.3; OTR: 6.9 ± 0.9; g/mm2). The ST was associated with preserved collagen content (YNT: 0.38 ± 0.05; ONT: 0.78 ± 0.12; OTR: 0.34 ± 0.09; %). Exercise partially mitigated the effects of aging on intracellular Ca2+-regulating protein (eg, L-Ca2+ channel and phospholamban) and β-isoform of myosin. Thus, we propose that these molecular alterations together with inhibition of collagen increase contribute to improved myocardial performance in older rats.Os efeitos do treinamento físico na contratilidade do miocárdio envelhecido são investigados há décadas, mas os resultados disponíveis ainda estão inclusivos. Assim, esse estudo analisou se o treinamento físico de natação (TN) poderia melhorar o inotropismo miocárdico de ratos idosos. Os ratos, de linhagem Wistar, machos, com idade de 4 (jovens) e 21 meses (idosos), foram distribuídos em grupos jovens sedentários (JS), idosos sedentários (IS) ou idosos treinados (IT), com seis semanas de TN. O impacto do TN na aptidão cardiorrespiratória foi analisado por meio da determinação do consumo de oxigênio no pico do exercício, em teste de esforço conduzido em esteira rolante. Soma-se a determinação do tempo de nado em teste de esforço suportando a carga externa de 10% do peso corporal. Exames ecocardiográficos e hemodinâmicos foram empregados na avaliação da morfologia e função ventricular esquerda. O inotropismo miocárdico foi estudado em músculos papilares em regime de contração isométrica in vitro. Preparações histológicas de tecido miocárdico foram aplicadas na determinação do volume nuclear dos cardiomiócitos e do teor de colágeno. Western blot foi aplicado para analisar a expressão miocárdica de proteínas modulam a cinética do cálcio e a função da miosina. Ratos idosos não apresentaram disfunção cardíaca, mas o grupo idoso sedentário apresentou menor desempenho físico durante o teste de natação [JS: 5 ± 2; IS: -16 ± 0,4; IT: 51 ± 3; (Δ%) segundos]. Além disso, o grupo IS mostrou pior inotropismo miocárdico, no qual foi revertido pelo TN (tensão máxima desenvolvida: JS: 6,2 ± 0,7; IS: 3,9 ± 0,3; IT: 6,9 ± 0,9; g/mm2). O TN foi associado à preservação do aumento no teor de colágeno (JS: 0,38 ± 0,05; IS: 0,78 ± 0,12; IT: 0,34 ± 0,09; %). O exercício atenuou parcialmente os efeitos do envelhecimento em proteínas reguladoras do Ca2+ [canal de cálcio tipo L (L-Ca2+) e fosfolambam (PLB) por exemplo] e isoforma beta da miosina (β-MHC). Assim, propomos que essas alterações moleculares, juntamente com a inibição do aumento de colágeno, contribuam para a melhoria do desempenho miocárdico em ratos idosos submetidos ao TN.Dados abertos - Sucupira - Teses e dissertações (2019

Low-Level Laser Application in the Early Myocardial Infarction Stage Has No Beneficial Role in Heart Failure

Low-level laser therapy (LLLT) has been targeted as a promising approach that can mitigate post infarction cardiac remodeling. There is some interesting evidence showing that the beneficial role of the LLLT could persist long-term even after the end of the application, but it remains to be systematically evaluated. Therefore, the present study aimed to test the hypothesis that LLLT beneficial effects in the early post-infarction cardiac remodeling could remain in overt heart failure even with the disruption of irradiations. Female Wistar rats were subjected to the coronary occlusion to induce myocardial infarction or Sham operation. A single LLLT application was carried out after 60 s and 3 days post-coronary occlusion, respectively. Echocardiography was performed 3 days and at the end of the experiment (5 weeks) to evaluate cardiac function. After the last echocardiographic examination. LV hemodynamic evaluation was performed at baseline and on sudden afterload increases. Compared with the Sham group, infarcted rats showed increased systolic and diastolic internal diameter as well as a depressed shortening fraction of LV. The only benefit of the LLLT was a higher shortening fraction after 3 days of infarction. However, treated-LLLT rats show a lower shortening fraction in the 5th week of study when compared with Sham and non-irradiated rats. A worsening of cardiac function was confirmed in the hemodynamic analysis as evidenced by the higher LV end-diastolic pressure and lower +dP/dt and dP/dt with five weeks of study. Cardiac functional reserve was also impaired by infarction as evidenced by an attenuated response of stroke work index and cardiac output to a sudden afterload stress, without LLLT repercussions. No significant differences were found in the myocardial expression of Akti NEGF pathway. Collectively, these findings illustrate that LLLT improves LV systolic function in the early post-infarction cardiac remodeling. However, this beneficial effect may be dependent on the maintenance of phototherapy. Long-term studies with LLLT application are needed to establish whether these effects ultimately translate into improved cardiac remodeling.Conselho Nacional de Desenvolvimento Cientifico e TecnologicoFAPESPNove de Julho Univ, Lab Biophoton, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Lab Cardiac Physiol, Sao Paulo, SP, BrazilNove de Julho Univ, Program Med, Sao Paulo, BrazilUniv Sao Judas Tadeu, Brazil Phys Educ & Aging Sci Program, Translat Physiol Lab, Sao Paulo, BrazilUniv Fed Sao Paulo, Lab Cardiac Physiol, Sao Paulo, SP, BrazilCNPq: 4400851/2014-8FAPESP: 09-54225/8FAPESP: 15/11028-9Web of Scienc

Evaluating restrictions on the circulation of freight vehicles in brazilian cities

Restrictions on the circulation of trucks are becoming increasingly frequent in Brazilian cities. Population growth, lack of appropriate urban infrastructure, and concern for the environment compel governments to adopt attitudes to reduce the problems of externalities in large urban centres. Traffic restrictions affect the full logistic chain, from the providers of consumer goods and services to the final consumers. Such restrictions usually apply to city centres, particularly during the peak hours, and for larger vehicles. This paper aims to identify Brazilian cities that have traffic restrictions and to estimate the odds of implementing certain types of traffic restrictionsEighth International Conference on City Logistics 17-19 June 2013, Bali, Indonesi

Are there gender differences in left ventricular remodeling after myocardial infarction in rats?

Objective: An unclear issue is whether gender may influence at cardiac remodeling after myocardial infarction (MI). We evaluated left ventricle remodeling in female and male rats post-MI. Methods: Rats were submitted to anterior descending coronary occlusion. Echocardiographic evaluations were performed on the first and sixth week post-occlusion to determine myocardial infarction size and left ventricle systolic function (FAC, fractional area change). Pulsed Doppler was applied to analyze left ventricle diastolic function using the following parameters: E wave, A wave, E/A ratio. Two-way ANOVA was applied for comparisons, complemented by the Bonferroni test. A P≤=0.05 was considered significant. Results: There were no significant differences between genders for morphometric parameters on first (MI [Female (FE): 44.0±5.0 vs. Male (MA): 42.0±3.0%]; diastolic [FE: 0.04±0.003 vs. MA: 0.037±0.005, mm/g] and systolic [FE: 0.03±0.0004 vs. MA: 0.028±0.005, mm/g] diameters of left ventricle) and sixth (MI [FE: 44.0±5.0 vs. MA: 42.0±3.0, %]; diastolic [FE: 0.043±0.01 vs. MA: 0.034±0.005, mm/g] and systolic [FE: 0.035±0.01 vs. MA: 0.027±0.005, mm/g] of LV) week. Similar findings were reported for left ventricle functional parameters on first (FAC [FE: 34.0±6.0 vs. MA: 32.0±4.0, %]; wave E [FE: 70.0±18.0 vs. MA: 73.0±14.0, cm/s]; wave A [FE: 20.0±12.0 vs. MA: 28.0±13.0, cm/s]; E/A [FE: 4.9±3.4 vs. MA: 3.3±1.8]) and sixth (FAC [FE: 29.0±7.0 vs. MA: 31.0±7.0, %]; wave E [FE: 85.0±18.0 vs. MA: 87.0±20.0, cm/s]; wave A [FE: 20.0±11.0 vs. MA: 28.0±17.0, cm/s]; E/A [FE: 6.2±4.0 vs. MA: 4.6±3.4]) week. Conclusion: Gender does not influence left ventricle remodeling post-MI in rats

Atrial fibrillation promotion in a rat model of heart failure induced by left ventricle radiofrequency ablation

Background: Atrial fibrillation (AF) frequently coexists with congestive heart failure (CHF). The increased susceptibility to AF in CHF has been attributed to a variety of structural and electrophysiological changes in the atria, particularly dilation and interstitial fibrosis. We evaluated atrial remodeling and AF vulnerability in a rat model of CHF induced by left ventricle (LV) radiofrequency (RF) ablation. Methods: Wistar rats were divided into 3 groups: RF-induced CHF (Ab, n = 36), CHF animals treated with spironolactone (AbSpi, n = 20) and sham controls (Sham, n = 29). After 12 weeks, animals underwent echocardiographic and electrophysiological evaluation and were sacrificed for histological (atrial fibrosis) and Western blotting (TGF-β1, collagen I/III, connexin 43 and CaV1.2) analysis. Results: Mild LV dysfunction and marked atrial enlargement were noted in both ablated groups. AF inducibility (episodes ≥2 s) increased in the Ab group compared to sham animals (31/36, 86%; vs. 15/29, 52%; p = 0.005), but did not differ from the AbSpi group (16/20, 80%; p = NS). Sustained AF (>30 s) was also more frequent in the Ab group compared to shams (56% vs. 28%; p = 0.04). Spironolactone reduced atrial fibrosis (p < 0.01) as well as TGF-β1 (p < 0.01) and collagen I/III (p < 0.01) expression but did not affect connexin 43 and CaV1.2 expression. Conclusions: Rats with RF-induced CHF exhibit pronounced atrial structural remodeling and enhanced AF vulnerability. This model may be useful for studying AF substrate in CHF. Keywords: Radiofrequency ablation, Atrial fibrosis, Heart failure, Atrial fibrillatio

A SINGLE LOW-LEVEL LASER APPLICATION REDUCES MYOCARDIAL INFARCTION SIZE, IMPROVES CARDIAC PERFORMANCE AND ATTENUATES APOPTOSIS IN REMOTE MYOCARDIUM

Nove de Julho Univ, Sao Paulo, BrazilUniv Fed Sao Paulo, Inst Heart, Rua Botucatu 862, BR-04023062 Sao Paulo, BrazilUniv Fed Sao Paulo, Inst Heart, Rua Botucatu 862, BR-04023062 Sao Paulo, BrazilWeb of Scienc

IV. Tools and Methods for Studying Cell Migration and Cell Rearrangement in Tissue and Organ Development

A vast diversity of biological systems, ranging from prokaryotes to multicellular organisms, show cell migration behavior. Many of the basic cellular and molecular concepts in cell migration apply to diverse model organisms. Drosophila, with its vast repertoire of tools for imaging and for manipulation, is one of the favorite organisms to study cell migration. Moreover, distinct Drosophila tissues and organs offer diverse cell migration models that are amenable to live imaging and genetic manipulations. In this review, we will provide an overview of the fruit fly toolbox that is of particular interest for the analysis of cell migration. We provide examples to highlight how those tools were used in diverse migration systems, with an emphasis on tracheal morphogenesis, a process that combines morphogenesis with cell migration