Luiz César Guarita-Souza

Os efeitos da pressão positiva intermitente e do incentivador respiratório no pós-operatório de revascularização miocárdica

BACKGROUND Pulmonary complications are important causes of morbidity and fatalities among patients subject to cardiac surgery. The respiratory physiotherapy has been aiding in the recovery of these patient ones. OBJECTIVE To evaluate the physiotherapeutic effect of intermittent positive pressure breathing (IPPB) and incentive spirometry (IS) in patients submitted to myocardial revascularization surgery. METHODS Forty patients were divided in two groups: one was submitted to IPPB (n=20) and the other to IS (n=20). The patients were evaluated at the preoperative period and 24, 48 and 72 hours postoperatively, with the resources being applied in the postoperative period. The following parameters were analyzed: oxygen saturation (SpO2), respiratory frequency (RF), minute volume (MV), current volume (CV), maximum inspiratory pressure (Ip max) and maximum expiratory pressure (Ep max). RESULTS The groups were considered homogeneous regarding the demographic and clinical variables. In the group submitted to IPPB, an increase in SpO2 was observed 48 (p=0.007) and 72 h (p=0.0001) after surgery, when compared to the IS group. As for the RF, MV and CV variables, there were no statistically significant differences between the groups. The group submitted to IS showed a significant increase in the Epmax 24 (p=0.02) and 48 (p=0.01) h after surgery. CONCLUSION Aiming at reversing hypoxemia earlier, IPPB showed to be more efficient when compared to IS; however, IS was more effective in improving respiratory muscle strength.

Evaluation of Bone Marrow Mesenchymal Stem Cell Standard Cryopreservation Procedure Efficiency

INTRODUCTION Mesenchymal stem cells are obtained from a variety of sources, particularly bone marrow. These cells have great potential for clinical research due to their potential to regenerate tissue. As is well known, the cryopreservation process can store any cell type, particularly blood cells, for an indeterminate time. OBJECTIVE The aim of this study was to analyze the efficiency of standard cryopreservation procedures for adult mesenchymal stem cells from bone marrow. METHODS Mononuclear stem cells isolated from 10 Wistar male rats were cultivated for 4 weeks to obtain mesenchymal stem cells. The parameters considered in this study were trypan blue exclusion test and annexin V conjugated with 7-amino-actinomycin for flow cytometry before cryopreservation in liquid nitrogen vapor phase for 1 month and after thawing. RESULTS The viabilities determined by the trypan blue exclusion test were 94.76% and 90.58%, and the flow cytometry assay (annexin V conjugated with 7-amino-actinomycin) were 85.52% and 66.25%, before cryopreservation and after thawing, respectively. CONCLUSIONS Standard procedures for cryopreservation were not efficient for those cells. The flow cytometry assay was more sensitive than the trypan blue exclusion test to demonstrate nonviability.

Functional Outcome of Bone Marrow Stem Cells (CD45+/CD34−) After Cell Therapy in Acute Spinal Cord Injury: In Exercise Training and in Sedentary Rats

BACKGROUND Cell therapy and exercise training may be options for spinal cord regeneration. Our objective was to evaluate the functional effects of autologous bone marrow stem cell (CD45(+)/CD34(-)) transplantation in acute spinal cord injury in exercise training and in sedentary rats. MATERIALS AND METHODS Fifty-five adult male Wistar rats underwent spinal cord contusion by Impactor (NYU). Locomotor rating scale was performed every 48 hours for 48 days. Animals with scores < or = 12 were randomly divided into 4 groups: sedentary without parenchymal cell infusion; sedentary with parenchymal cell infusion; swimming training without parenchymal cell infusion; and swimming training with parenchymal cell infusion. Bone marrow stem cells were isolated by puncture-aspiration of the bone marrow and density gradient (d = 1.077). The animals underwent a 60-minute swimming session 6 times/week supporting an overload of 3% of body weight for 6 consecutive weeks. Comparisons between the groups in relation to differences between the beginning to the end of scores used the nonparametric Bonferroni test and post-hoc Mann-Whitney U test to identify significance. RESULTS Forty-two rats that obtained scores < or = 12 underwent therapy with 9 animals in each of the 4 groups as completors (n = 36). There was significance (P < or = .008) for sedentary without parenchymal cell infusion vs swimming training with parenchymal cell infusion. CONCLUSION The combination of bone marrow stem cell therapy (CD45(+)/CD34(-)) and exercise training resulted in significant functional improvement in acute spinal cord injury.

Stem Cell Therapy in Heart Diseases: A Review of Selected New Perspectives, Practical Considerations and Clinical Applications

Degeneration of cardiac tissues is considered a major cause of mortality in the western world and is expected to be a greater problem in the forthcoming decades. Cardiac damage is associated with dysfunction and irreversible loss of cardiomyocytes. Stem cell therapy for ischemic heart failure is very promising approach in cardiovascular medicine. Initial trials have indicated the ability of cardiomyocytes to regenerate after myocardial injury. These preliminary trials aim to translate cardiac regeneration strategies into clinical practice. In spite of advances, current therapeutic strategies to ischemic heart failure remain very limited. Moreover, major obstacles still need to be solved before stem cell therapy can be fully applied. This review addresses the current state of research and experimental data regarding embryonic stem cells (ESCs), myoblast transplantation, histological and functional analysis of transplantation of co-cultured myoblasts and mesenchymal stem cells, as well as comparison between mononuclear and mesenchymal stem cells in a model of myocardium infarction. We also discuss how research with stem cell transplantation could translate to improvement of cardiac function.

Estudo comparativo entre a pressão positiva intermitente (Reanimador de Müller) e contínua no pós-operatório de cirurgia de revascularização do miocárdio

OBJECTIVE To compare the effect of the use of intermittent and continuous positive airway pressure in postoperative patients undergoing coronary artery bypass grafting. METHODS This study included forty patients divided into two groups: one undergoing continuous positive airway pressure (CPAP Group), and the other undergoing intermittent pressure (Müller Resuscitator Group). The patients were evaluated in relation to the several study variables at the following time points: preoperative, 3rd, 24th, and 48th hours. RESULTS The patient groups were homogeneous in relation to the several demographic and clinical variables. The values of pO2, pCO2 and sO2 were within normal limits and no significant differences were found between the groups. Regarding respirometry, the groups showed significant differences in the tidal volume and respiratory rate at the 48th postoperative hour. Dyspnea and use of accessory muscle in postoperative assessments were found with a significantly higher frequency in patients undergoing CPAP. Patients undergoing Müller Resuscitator had a normal chest radiograph more frequently than did patients undergoing CPAP. CONCLUSION Both devices were shown to be able to keep pO2, pCO2, and sO2 values within normal limits. However, when the objective was pulmonary reexpansion with less imposed workload, the Müller Resuscitator was more effective because of its prompter action and consequently lower levels of dyspnea, respiratory rate (RR) and use of accessory muscle were observed.

Ischaemic heart disease deaths in Brazil: current trends, regional disparities and future projections

Objective To quantify the trend of ischaemic heart disease (IHD) deaths in Brazil during the last decade (2000–2010) for various population characteristics and to forecast the upcoming mortality trends across regions in Brazil until the year 2015. Design Nationwide comparative observational study. Patients and methods The population studied encompassed all adult residents (≥20 years) living in five Brazilian regions between 2000 and 2010. Demographic, economic and mortality data were obtained from Brazilian National Mortality Data System and National Applied Economics Research Institute. Subnotified deaths were redistributed proportionally to IHD deaths. Age-standardised mortality rates (ASMRs) per 100 000 inhabitants, by sex and region, were calculated employing a standard Brazilian population and constructing multivariate regression models to quantify and to project temporal trends. Main outcome measures Absolute numbers of death due to IHD and region-specific death rates in Brazil by age and sex. Results During the study period, 627 786 men and 452 690 women died due to IHD in Brazil. ASMR trends across all regions for men and women converged, driven by a declining trend in the South and Southeast and an opposite incline in the North and Northeast (p<0.05). Future projections demonstrated potential widening of the observed North–South gap in coming years. Conclusions The IHD death trend in Brazil has changed from a decline to a stagnant state. However, a significant discrepancy in mortality trends exists between the northern and southern regions, which is likely to widen further. Reappraisal of the public health policies tailored to populations with diverse socioeconomic structures is urgently required.

Comparison of mononuclear and mesenchymal stem cell transplantation in myocardium infarction

Background: Bone marrow stem cell (SC) transplantation into failing myocardium has emerged as a novel therapeutic option for the treatment of ventricular dysfunction. Both mononuclear (MoSC) and mesenchymal (MeSC) stem cells have been proposed as ideal cell types to this goal. The objective of this study is to compare the efficacy of these cells in improving ventricular function in a rat model of postinfarct ventricular dysfunction. Method: Myocardial infarction was induced in Wistar rats by left coronary occlusion. After 1 week, 42 animals with resulting ejection fractions (EF) lower than 30% were included in the study. MoSC and MeSC were obtained from bone marrow aspirates and separated by the Ficoll-Hypaque method. MeSC were cultured for 14 days before injection. Nine days after infarction, rats received intramyocardial injections of MoSC (n=8), MeSC (n=13) or culture medium as a control (n=21). Echocardiographic evaluation was performed at baseline and after one month. Results: There were no significant differences in the baseline ejection fractions or the left ventricular end diastolic volumes (LVEDV) between all groups. After 1 month, ejection fraction decreased in the Control Group and remained unchanged in MoSC and MeSC Groups. In all three groups ventricular dilation was observed. Histopathology of the infarcted area where injections were performed identified new smooth muscle cells and endothelial cells in the MeSC Group and only new endothelial cells in MoSC Group Conclusions: Both MoSC and MeSC provided stabilization in the ejection fraction in this post-infarction ventricular dysfunction model however, no therapy prevented ventricular dilation.

Stem cell death and survival in heart regeneration and repair.

Cardiovascular diseases are major causes of mortality and morbidity. Cardiomyocyte apoptosis disrupts cardiac function and leads to cardiac decompensation and terminal heart failure. Delineating the regulatory signaling pathways that orchestrate cell survival in the heart has significant therapeutic implications. Cardiac tissue has limited capacity to regenerate and repair. Stem cell therapy is a successful approach for repairing and regenerating ischemic cardiac tissue; however, transplanted cells display very high death percentage, a problem that affects success of tissue regeneration. Stem cells display multipotency or pluripotency and undergo self-renewal, however these events are negatively influenced by upregulation of cell death machinery that induces the significant decrease in survival and differentiation signals upon cardiovascular injury. While efforts to identify cell types and molecular pathways that promote cardiac tissue regeneration have been productive, studies that focus on blocking the extensive cell death after transplantation are limited. The control of cell death includes multiple networks rather than one crucial pathway, which underlies the challenge of identifying the interaction between various cellular and biochemical components. This review is aimed at exploiting the molecular mechanisms by which stem cells resist death signals to develop into mature and healthy cardiac cells. Specifically, we focus on a number of factors that control death and survival of stem cells upon transplantation and ultimately affect cardiac regeneration. We also discuss potential survival enhancing strategies and how they could be meaningful in the design of targeted therapies that improve cardiac function.

Efeitos agudos do exercício físico prolongado: avaliação após ultramaratona de 24 horas

BACKGROUND The consequences and risks of prolonged physical exercise are not well established. OBJECTIVE To evaluate the effects of prolonged physical exercise on the participants of a 24-hour ultramarathon race. METHODS Twenty male runners were selected for evaluation a day before and immediately after the race, where the athletes had to cover the most distance in 24 hours. Clinical, laboratory and echocardiographic data were obtained at both evaluations. RESULTS Mean distance covered was 140.3 ± 18.7 km. Runners showed weight loss (p < 0.001) and decrease in systolic (p < 0.001) and diastolic (p = 0.004) blood pressure. Hematological changes were compatible with the physiological stress. Plasma levels of creatine phosphokinase strikingly increased post-race (163.4 ± 56.8 vs. 2978.4 ± 1921.9 U/L; p < 0.001) and was inversely correlated with distance covered: those who covered the longest distances showed the lowest CPK levels (Pearson r = 0.69, p = 0.02). After the race, 2 runners showed a slight increase in Troponin levels. One of them also had simultaneous decrease in left ventricular ejection fraction (coronary artery disease was subsequently ruled out). Basal echocardiography assessment had shown LV hypertrophy in one and increased left atrial volume in five runners. After the race, there was a decrease in E/A ratio (p < 0.01). CONCLUSION Prolonged physical exercise is associated with metabolic and cardiovascular alterations. Cardiac abnormalities found in our study suggest that cardiac fatigue may occur in this specific race modality. The long-term effect of these alterations, while maintaining the routine practice of prolonged strenuous physical activity, is still unknown.

Efeitos de curto prazo de um programa de atividade física moderada em pacientes com síndrome metabólica

ABSTRACT Objectives: To evaluate whether a short-term moderate intensity exercise program could change inflammatory parameters, and improve different components of metabolic syndrome in sedentary patients. Methods: Sixteen patients completed the 12-week program of supervised exercise, which consisted of a 40 to 50 minutes of walking, 3 times a week, reaching 50 to 60% of the heart rate reserve. The parameters evaluated before and after intervention were waist circumference, systolic and diastolic blood pressure, triglycerides, LDL cholesterol, HDL cholesterol, total cholesterol, C-reactive protein and interleukin 8. Results: There was a significant reduction in waist circumference (102.1±7.5cm to 100.8±7.4cm; p=0.03) and in body mass index (29.7±3.2kg/m2 versus 29.3±3.5kg/m2; p=0.03). Systolic blood pressure dropped from 141±18 to 129±13mmHg and diastolic from 79±12 to 71±10mmHg (with p<0.05 for both). No changes were observed on total cholesterol, LDL cholesterol and triglycerides, although HDL cholesterol levels improved, from 45.5±6.0 to 49.5±9.8mg/dL (p=0.02). There was a trend toward reduction of C-reactive protein (8.3%; p=0.07) and interleukin 8 levels (17.4%; p=0.058). The improvement in cardiovascular capacity was demonstrated by an increase of 13% in estimated volume of oxygen (p<0.001). Conclusion: Benefits of aerobic exercise of moderate intensity were seen within only 12 weeks of training in sedentary patients with metabolic syndrome. Considering the easy self-applicability and proven metabolic effects, an exercise program could be a first approach to sedentary patients with metabolic syndrome.