The risk of vector transmission of Trypanosoma cruzi remains high in the State of Paraná.

BACKGROUND: Monitoring and analysing the infection rates of the vector of Trypanosoma cruzi, that causes Chagas disease, helps assess the risk of transmission. OBJECTIVES: A study was carried out on triatomine in the State of Paraná, Brazil, between 2012 and 2021 and a comparison was made with a previous study. This was done to assess the risk of disease transmission. METHODS: Ecological niche models based on climate and landscape variables were developed to predict habitat suitability for the vectors as a proxy for risk of occurrence. FINDINGS: A total of 1,750 specimens of triatomines were recorded, of which six species were identified. The overall infection rate was 22.7%. The areas with the highest risk transmission of T. cruzi are consistent with previous predictions in municipalities. New data shows that climate models are more accurate than landscape models. This is likely because climate suitability was higher in the previous period. MAIN CONCLUSION: Regardless of uneven sampling and potential biases, risk remains high due to the wide presence of infected vectors and high environmental suitability for vector species throughout the state and, therefore, improvements in public policies aimed at wide dissemination of knowledge about the disease are recommended to ensure the State remains free of Chagas disease.

The risk of vector transmission of Trypanosoma cruzi remains high in the State of Paraná

BACKGROUND Monitoring and analysing the infection rates of the vector of Trypanosoma cruzi, that causes Chagas disease, helps assess the risk of transmission. OBJECTIVES A study was carried out on triatomine in the State of Paraná, Brazil, between 2012 and 2021 and a comparison was made with a previous study. This was done to assess the risk of disease transmission. METHODS Ecological niche models based on climate and landscape variables were developed to predict habitat suitability for the vectors as a proxy for risk of occurrence. FINDINGS A total of 1,750 specimens of triatomines were recorded, of which six species were identified. The overall infection rate was 22.7%. The areas with the highest risk transmission of T. cruzi are consistent with previous predictions in municipalities. New data shows that climate models are more accurate than landscape models. This is likely because climate suitability was higher in the previous period. MAIN CONCLUSION Regardless of uneven sampling and potential biases, risk remains high due to the wide presence of infected vectors and high environmental suitability for vector species throughout the state and, therefore, improvements in public policies aimed at wide dissemination of knowledge about the disease are recommended to ensure the State remains free of Chagas disease.

Description of a new species of the genus Lutzomyia França, 1924 (Diptera: Phlebotominae) and of the male of Lutzomyia fonsecai (Costa Lima, 1932).

Lutzomyia itambe sp. n. is described as a new species of neotropical cavernicolous phlebotomine sand fly based on specimens of males and females collected in the Gruta do Itambé, Altinópolis municipality, São Paulo State. In addition to this, we describe the male of Lutzomyia fonsecai (Costa Lima, 1932) collected near their type-locality in Bolivia. These descriptions are supported by illustrations that detail the morphological and morphometrical characteristics of the specimens. Lutzomyia itambe sp. n., L. fonsecai, along with L. dispar Martins & Silva, 1963, comprise the already named "Fonsecai complex". Both sex present parallel labial sutures, not forked, and males can be differentiated by parameral characters, while in females the distinction is made by characters of the palpi and spermathecae.

Photobiomodulation therapy's effects on cardiac fibrosis activation after experimental myocardial infarction.

INTRODUCTION: Ischemic heart disease is the leading cause of death worldwide, and interventions to reduce myocardial infarction (MI) complications are widely researched. Photobiomodulation therapy (PBMT) has altered multiple biological processes in tissues and organs, including the heart. OBJECTIVES: This study aimed to assess the temporal effects of PBMT on cardiac fibrosis activation after MI in rats. In this proof-of-concept study, we monitored the change in expression patterns over time of genes and microRNAs (miRNAs) involved in the formation of cardiac fibrosis post-MI submitted to PBMT. MATERIALS AND METHODS: Experimental MI was induced, and PBMT was applied shortly after coronary artery ligation (laser light of wavelength 660 nm, 15 mW of power, energy density 22.5 J/cm2 , 60 seconds of application, irradiated area 0.785 cm2 , fluence 1.1 J/cm2 ). Ventricular septal samples were collected at 30 minutes, 3, 6, 24 hours, and 3 days post-MI to determine temporal PBMT's effects on messenger RNA (mRNA) expression associated with cardiac fibrosis activation and miRNAs expression. RESULTS: PBMT, when applied after ischemia, reversed the changes in mRNA expression of myocardial extracellular matrix genes induced by MI. Surprisingly, PBMT modified cardiac miRNAs expression related to fibrosis replacement in the myocardium. Expression correlations between myocardial mRNAs were assessed. The correlation coefficient between miRNAs and target mRNAs was also determined. A positive correlation was detected among miR-21 and transforming growth factor beta-1 mRNA. The miR-29a expression negatively correlated to Col1a1, Col3a1, and MMP-2 mRNA expressions. In addition, we observed that miR-133 and Col1a1 mRNA were negatively correlated. CONCLUSION: The results suggest that PBMT, through the modulation of gene transcription and miRNA expressions, can interfere in cardiac fibrosis activation after MI, mainly reversing the signaling pathway of profibrotic genes.

Physical exercise attenuates stress-induced hypertension in rats but not the impairments on the myocardial mechanics.

BACKGROUND: Acute and chronic stresses have become a health problem in the contemporary society, and prolonged exposure to stressful events are related to the pathogenesis of cardiovascular diseases. Physical exercise is a well-recognized effective nonpharmacological therapy for cardiovascular diseases and stress-induced injuries. Thus, this study evaluated the effect of exercise on the cardiac remodelling of chronically stressed rats. METHODS AND RESULTS: Wistar adult rats were used (n = 10 each group) and chronic stress protocol consisted of restricting movement in individual rodent restrainers (60 min, 5 days/week, 12 weeks); and exercise consisted of swimming sessions in a pool (60 min, 5 days/week, 12 weeks). During protocol, blood pressure was measured in conscious rats, and at the end cardiac morphology/function was assessed. Animals exposed to stress exhibited continuous rise in blood pressure from the sixth week, but exercise attenuated it. Similarly, restrained rats increased serum corticosterone compared with nonstressed rats, but exercise also prevented it. No changes were found in cardiac mass, but chronic stress not only impaired the steady state contractions of the cardiac muscle, but also reduced inotropic responses to stretching, increasing calcium and beta-adrenergic receptor stimulation. Despite this, exercise was unable to prevent these functional impairments induced by stress, and instead, the association of stress and physical exercise worsened myocardial compliance. CONCLUSION: Despite the known benefits to the cardiovascular system, our results indicate that aerobic swimming exercise for 12 weeks reduced blood pressure but did not impede the chronic stress-induced myocardial damages in rats.

Description of the female and redescription of the male of Sciopemyia sordellii (Shannon & Del Ponte, 1927), including the description of four new species of the genus Sciopemyia Barretto, 1962 (Diptera: Psychodidae: Phlebotominae) from Brazil.

Currently, there are 1,047 sand fly species described worldwide. Brazil holds the greatest species richness in the Americas. The genus Sciopemyia Barretto, 1962 consists of eight species with Sciopemyia sordellii as its type species. Described by Shannon & Del Ponte in 1927, based on a single male specimen from Argentina, it has two junior synonymies: Phlebotomus nordestinus Mangabeira, 1942 and Phlebotomus longicornutus Floch & Abonnenc, 1943. The female of Sc. sordellii was not formally described and, until now, the female described as Ph. longicornutus was considered the female of Sc. sordellii. Here, we provide the description of the female of Sc. sordellii as well as a detailed redescription of the male. In addition, after a taxonomic review of specimens previously identified as Sc. sordellii or "Sc. microps aff." we propose the description of four new species. To obtain morphological and morphometrical data, specimens deposited in the "Coleção de Flebotomíneos" (FIOCRUZ/COLFLEB) and in the "Coleção de Flebotomíneos da Faculdade de Saúde Pública da Universidade de São Paulo" (LESP-Phlebotominae) were analyzed. Descriptions of Sciopemyia species and their synonymies were checked. A total of 318 specimens (145 females and 173 males) were examined and firstly grouped as morphospecies. Within the genus Sciopemyia, the closest species to Sc. sordellii is Sc. vattierae, whose males are separated by the size of flagellomere I, aedeagal ducts and epandrial lobe. Females, on the other hand, show differences in the spermathecae. The female of Sciopemyia apicalis sp. n. remains unknown; Wheareas, the male is morphologically closer to Sc. sordellii, and they differ on the arrangement of the spines of the gonostyle. Sciopemyia dantastorresi sp. n. and Sciopemyia shimabukuroae sp. n. are sister species, whose identification is only possible from male specimens, since no differences were found between females. The female of Sciopemyia birali sp. n. is similar to the females of Sc. microps and Sc. servulolimai but is distinguished from them by characters of the cibarium, palps, and individual spermathecal ducts. The male of Sciopemyia birali sp. n. remains unknown. Drawings and a dichotomous key for both sexes are provided.

Hyperbaric oxygenation improves redox control and reduces mortality in the acute phase of myocardial infarction in a rat model.

Among the mechanisms of action of hyperbaric oxygenation (HBO), the chance of reducing injury by interfering with the mechanisms of redox homeostasis in the heart leads to the possibility of extending the period of viability of the myocardium at risk. This would benefit late interventions for reperfusion to the ischemic area. The objective of the present study was to investigate the changes in the redox system associated with HBO therapy maintained during the first hour after coronary occlusion in an acute myocardial infarction (MI) rat model. Surviving male rats (n=105) were randomly assigned to one of three groups: Sham (SH=26), myocardial infarction (MI=45) and infarction+hyperbaric therapy (HBO=34, 1 h at 2.5 atm). After 90 min of coronary occlusion, a sample of the heart was collected for western blot analysis of total protein levels of superoxide dismutase, catalase, peroxiredoxin and 3­nitrotyrosine. Glutathione was measured by enzyme­linked immunosorbent assay (ELISA). The detection of the superoxide radical anion was carried out by oxidation of dihydroethidium analyzed with confocal microscopy. The mortality rate of the MI group was significantly higher than that of the HBO group. No difference was noted in the myocardial infarction size. The oxidized/reduced glutathione ratio and peroxiredoxin were significantly higher in the SH and MI when compared to the HBO group. Superoxide dismutase enzymes and catalase were significantly higher in the HBO group compared to the MI and SH groups. 3­Nitrotyrosine and the superoxide radical were significantly lower in the HBO group compared to these in the MI and SH groups. These data demonstrated that hyperbaric oxygenation therapy decreased mortality by improving redox control in the hearts of rats in the acute phase of myocardial infarction.

Linear periodization of strength training in blocks attenuates hypertension and diastolic dysfunction with normalization of myocardial collagen content in spontaneously hypertensive rats.

BACKGROUND AND METHOD: This study evaluated the effects of a linear block strength training programme on the parameters of cardiac remodelling in spontaneously hypertensive rats. Thirty-nine rats were equally distributed in four groups: normotensive sedentary, normotensive trained, hypertensive sedentary and hypertensive trained. The strength training protocol was organized in three mesocycles of 4 weeks, with an increase in the training load organized in a linear fashion for each block, considering the weight established in the maximum loaded load test. The following parameters were evaluated: ventricular function assessed by echocardiogram, caudal blood pressure, ventricular haemodynamics and cardiac masses. Two-way analysis of variance was used to determine the differences between the group and time. RESULTS: After 12 weeks of training, the hypertensive trained group presented the following results: increased muscle strength, reduced blood pressure, reduced heart rate, isovolumetric relaxation time and total collagen content, with increased cardiac function, without promoting changes in the mass and nuclear volume of cardiomyocytes. Also, blood pressure reduction seems to be associated with both muscle strength adjustments and total load progress. CONCLUSION: The findings of this study showed that the training programme carried out attenuated systemic arterial pressure and preserved the ventricular function of spontaneously hypertensive rats without cardiac mass change.

Delayed Reperfusion-Coronary Artery Reperfusion Close to Complete Myocardial Necrosis Benefits Remote Myocardium and Is Enhanced by Exercise.

The present study aimed to analyze the effects of reperfusion of a distant coronary artery on cardiac function, the ultrastructure, and the molecular environment of the remote myocardium immediately after the completion of myocardial regional necrosis: delayed reperfusion (DR). Additionally, the effects of prior exercise on the outcomes of DR were investigated. Female rats with permanent occlusion or delayed reperfusion were randomly assigned to an exercise (swimming, 1 h/day, 5 days/week for 8 weeks) or sedentary protocol. Thus, the study included the following four groups: sedentary permanent occlusion, exercise permanent occlusion, sedentary delayed reperfusion, and exercise delayed reperfusion. The descending coronary artery was occluded for 1 h. Reperfusion was confirmed by contrast echocardiography, and the rats were observed for 4 weeks. Permanent occlusion and DR caused similar myocardial infarction sizes among the four groups. Interestingly, exercise significantly decreased the mortality rate. Delayed reperfusion resulted in significant benefits, including enhanced hemodynamics and papillary muscle contraction, as well as reduced apoptosis and collagen content. Protein calcium kinetics did not change. Meanwhile, developed tension and the Frank-Starling mechanism were enhanced, suggesting that calcium sensitivity was intensified in myofilaments. Remarkable remote myocardial benefits occurred after distant DR, and prior exercise intensified cardiac recovery. Our findings provide valuable information about DR. Our data might explain the better clinical outcomes in recent studies showing that late reperfusion could improve heart failure in patients with myocardial infarction. In conclusion, DR has remote myocardial benefits, including inotropism enhancement, pulmonary congestion reduction, and collagen and apoptosis attenuation, which are enhanced by prior exercise.

Multivariate linear regression analysis to evaluate multiple-set performance in active and inactive individuals

Abstract Aim: To determine how EMG, anthropometric, and psychological factors, and physical activity levels affect isokinetic peak torque performance (IPT) of multiple set exercise sessions. Methods: 20 participants (27±7 years old), classified as active (A=10) and inactive (I=10), performed 10x10:40secs of maximal unilateral knee flexions and extensions at 120o.s-1. The IPT, EMG, glucose, LDH, and lactate concentrations and perceptions of pain, effort, recovery. Results: Active volunteers showed higher muscularity (52±5 vs 47±4 cm; p<0.05), PTI (262±4 vs 185±4 Nm; p<0.05), relative lower drop in performance (14±2 vs 27±3% ; p<0.05), major MDF (83±1 vs 76±1 Hz; p<0.05), lower log -Fins5 (-12.9±0.3 vs -12.7 ± 0.3 Hz; p<0.05), smaller subjective perception of effort (14.8±0.3 vs 17.0±0.3) and higher subjective perception of recovery (14.2±0.2 vs 12.3±0.3). There was a significant interaction between relative fatigue and the number of sets (F=6.18; p<0.001). Stepwise multiple regressions revealed that subjective perception of recovery best explained the fatigue level generated in the active volunteers [fatigue level= 85.084-5255(SPR)] while for body mass was the best determinant for the inactive group [fatigue level = -21.560 +1.828(BMI)]. Conclusion: Data from the present analysis suggest that physically active individuals show higher torque development and a smaller fatigability index when compared to inactive individuals. Among the fatigue models studied, it is possible that alterations in biochemical components, psychophysiological and EMG are not sensitive to the direct influence of the fatigue dynamics protocol, both in active or inactive individuals.

Effects of previous carbohydrate supplementation on muscular fatigue: double-blind, randomized, placebo-controlled crossover study

Aims: The aim of this study was to examine the effects of previous carbohydrate supplementation on high-volume resistance exercise performance Methods: Twenty males physically independent adults aged ≥18 years participated in a double-blind randomized placebo-controlled crossover study. Sixty minutes before the experimental protocol, each participant ingested 0,6 g.kg of body mass-1 of carbohydrate supplementation or placebo. Maximum voluntary isometric contraction tests were performed before and after the dynamic fatigue induction protocol consisting of 10 sets of 8 repetitions of right leg knee extensors at 120º s-1. Results: Lower decrement of the isometric peak torque (p<0,001) and of the rate of torque development (p<0,001) was observed in carbohydrate supplementation after the dynamic protocol. Both concentric and eccentric peak torque differed significantly (p<0,001) between carbohydrate supplementation and placebo treatments from the second set, although the slope of the force-repetitions curve was not different between them. Additionally, the carbohydrate supplementation resulted in a lower session rating of perceived exertion (p<0,05). Conclusions: Previous carbohydrate supplementation attenuates muscle fatigue and internal load exercise in a high-volume isokinetic leg protocol.(AU)

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-ß1, 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-ß1 (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.

Early Seizure Detection Based on Cardiac Autonomic Regulation Dynamics.

Epilepsy is a neurological disorder that causes changes in the autonomic nervous system. Heart rate variability (HRV) reflects the regulation of cardiac activity and autonomic nervous system tone. The early detection of epileptic seizures could foster the use of new treatment approaches. This study presents a new methodology for the prediction of epileptic seizures using HRV signals. Eigendecomposition of HRV parameter covariance matrices was used to create an input for a support vector machine (SVM)-based classifier. We analyzed clinical data from 12 patients (9 female; 3 male; age 34.5 ± 7.5 years), involving 34 seizures and a total of 55.2 h of interictal electrocardiogram (ECG) recordings. Data from 123.6 h of ECG recordings from healthy subjects were used to test false positive rate per hour (FP/h) in a completely independent data set. Our methodological approach allowed the detection of impending seizures from 5 min to just before the onset of a clinical/electrical seizure with a sensitivity of 94.1%. The FP rate was 0.49 h-1 in the recordings from patients with epilepsy and 0.19 h-1 in the recordings from healthy subjects. Our results suggest that it is feasible to use the dynamics of HRV parameters for the early detection and, potentially, the prediction of epileptic seizures.

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 Akt1/VEGF 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.

Evaluating the Adaptation Process of Sandfly Fauna to Anthropized Environments in a Leishmaniasis Transmission Area in the Brazilian Amazon.

Phlebotomines (Diptera: Psychodidae) are vectors of several etiological agents of human and animal diseases, including protozoans of the gender Leishmania. Precarious socioeconomic conditions and uncontrolled population growth directly influence the transmission risk of parasites and the urbanization of vector species, previously restricted to wild environments. The Marajó Archipelago is considered a high incidence area of leishmaniasis in the Brazilian Amazon. However, it is poorly studied. The aim of this study was to assess the adaptation processes of phlebotomine species to anthropized environments in this region. For this purpose, the phlebotomine fauna was compared between three municipalities of the Marajó Archipelago: Anajás, Portel, and São Sebastião da Boa Vista. To survey the phlebotomine fauna, CDC (Center for Disease Control) light traps were installed in the wild areas and in the intra and peridomiciliary areas of rural and urban environments. The environments studied presented a diversified phlebotomine fauna, with higher richness in the wild environment (15 species), followed by the rural (seven species), and finally, the urban environment (three species). A migration of wild fauna to the adjacent anthropized areas (rural environment) and to urban areas was observed, evidencing the adaptation process of this vector to anthropized environments in the studied region. Thus, our study evidenced that the disorganized human occupation and utilization of the landscape might cause the invasion of urban areas by wild populations of phlebotomines, in this way enabling the settlement of urban leishmaniasis transmission cycles.

Exercise Training Attenuates Right Ventricular Remodeling in Rats with Pulmonary Arterial Stenosis.

Introduction: Pulmonary arterial stenosis (PAS) is a congenital defect that causes outflow tract obstruction of the right ventricle (RV). Currently, negative issues are reported in the PAS management: not all patients may be eligible to surgeries; there is often the need for another surgery during passage to adulthood; patients with mild stenosis may have later cardiac adverse repercussions. Thus, the search for approaches to counteract the long-term PAS effects showed to be a current target. At the study herein, we evaluated the cardioprotective role of exercise training in rats submitted to PAS for 9 weeks. Methods and Results: Exercise resulted in improved physical fitness and systolic RV function. Exercise also blunted concentric cavity changes, diastolic dysfunction, and fibrosis induced by PAS. Exercise additional benefits were also reported in a pro-survival signal, in which there were increased Akt1 activity and normalized myocardial apoptosis. These findings were accompanied by microRNA-1 downregulation and microRNA-21 upregulation. Moreover, exercise was associated with a higher myocardial abundance of the sarcomeric protein α-MHC and proteins that modulate calcium handling-ryanodine receptor and Serca 2, supporting the potential role of exercise in improving myocardial performance. Conclusion: Our results represent the first demonstration that exercise can attenuate the RV remodeling in an experimental PAS. The cardioprotective effects were associated with positive modulation of RV function, survival signaling pathway, apoptosis, and proteins involved in the regulation of myocardial contractility.

Comparative mRNA and MicroRNA Profiling during Acute Myocardial Infarction Induced by Coronary Occlusion and Ablation Radio-Frequency Currents.

The ligation of the left anterior descending coronary artery is the most commonly used experimental model to induce myocardial infarction (MI) in rodents. A high mortality in the acute phase and the heterogeneity of the size of the MI obtained are drawbacks recognized in this model. In an attempt to solve the problem, our group recently developed a new MI experimental model which is based on application of myocardial ablation radio-frequency currents (AB-RF) that yielded MI with homogeneous sizes and significantly reduce acute mortality. In addition, cardiac structural, and functional changes aroused by AB-RF were similar to those seen in animals with MI induced by coronary artery ligation. Herein, we compared mRNA expression of genes that govern post-MI milieu in occlusion and ablation models. We analyzed 48 mRNAs expressions of nine different signal transduction pathways (cell survival and metabolism signs, matrix extracellular, cell cycle, oxidative stress, apoptosis, calcium signaling, hypertrophy markers, angiogenesis, and inflammation) in rat left ventricle 1 week after MI generated by both coronary occlusion and AB-RF. Furthermore, high-throughput miRNA analysis was also assessed in both MI procedures. Interestingly, mRNA expression levels and miRNA expressions showed strong similarities between both models after MI, with few specificities in each model, activating similar signal transduction pathways. To our knowledge, this is the first comparison of genomic alterations of mRNA and miRNA contents after two different MI procedures and identifies key signaling regulators modulating the pathophysiology of these two models that might culminate in heart failure. Furthermore, these analyses may contribute with the current knowledge concerning transcriptional and post-transcriptional changes of AB-RF protocol, arising as an alternative and effective MI method that reproduces most changes seem in coronary occlusion.

Previous exercise training increases levels of PPAR-α in long-term post-myocardial infarction in rats, which is correlated with better inflammatory response.

OBJECTIVE: Exercise is a protective factor for cardiovascular morbidity and mortality, with unclear mechanisms. Changing the myocardial metabolism causes harmful consequences for heart function and exercise contributes to metabolic adjustment modulation. Peroxisome proliferator-activated receptors (PPARs) are also myocardium metabolism regulators capable of decreasing the inflammatory response. We hypothesized that PPAR-α is involved in the beneficial effects of previous exercise on myocardial infarction (MI) and cardiac function, changing the expression of metabolic and inflammatory response regulators and reducing myocardial apoptosis, which partially explains the better outcome. METHODS AND RESULTS: Exercised rats engaged in swimming sessions for 60 min/day, 5 days/week, for 8 weeks. Both the exercised rats and sedentary rats were randomized to MI surgery and followed for 1 week (EI1 or SI1) or 4 weeks (EI4 or SI4) of healing or to sham groups. Echocardiography was employed to detect left ventricular function and the infarct size. Additionally, the TUNEL technique was used to assess apoptosis and immunohistochemistry was used to quantitatively analyze the PPAR-α, TNF-α and NF-κB antigens in the infarcted and non-infarcted myocardium. MI-related mortality was higher in SI4 than in EI4 (25% vs 12%), without a difference in MI size. SI4 exhibited a lower shortening fraction than EI4 did (24% vs 35%) and a higher apoptosis/area rate (3.97±0.61 vs 1.90±1.82) in infarcted areas (both p=0.001). Immunohistochemistry also revealed higher TNF-α levels in SI1 than in EI1 (9.59 vs 4.09, p<0.001) in infarcted areas. In non-infarcted areas, EI4 showed higher levels of TNF-α and positive correlations between PPAR-α and NF-κB (r=0.75, p=0.02), in contrast to SI4 (r=0.05, p=0.87). CONCLUSION: Previously exercised animals had better long-term ventricular function post-MI, in addition to lower levels of local inflammatory markers and less myocardial apoptosis, which seemed to be related to the presence of PPAR-α.