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.
Background-Cellular transplantation is emerging as a promising strategy for the treatment of postinfarction ventricular dysfunction. Whether its beneficial effects can be extended to other cardiomyopathies remains an unexplored question. We evaluated the histological and functional effects of simultaneous autologous transplantation of co-cultured stem cells and skeletal myoblasts in an experimental model of dilated cardiomyopathy caused by Chagas disease, characterized by diffuse fibrosis and impairment of microcirculation. Methods and Results-Wistar rats weighing 200 grams were infected intraperitoneally with 15ϫ10 4 trypomastigotes. After 8 months, 2-dimensional echocardiographic study was performed for baseline assessment of left ventricle (LV) ejection fraction (EF) (%), left ventricle end-diastolic volume (LVEDV) (mL), and left ventricle end-systolic volume (LVESV) (mL). Animals with LV dysfunction (EF Ͻ37%) were selected for the study. Autologous skeletal myoblasts were isolated from muscle biopsy and mesenchymal stem cells from bone marrow aspirates were co-cultured in vitro for 14 days, yielding a cell viability of Ͼ90%. Eleven animals received autologous transplant of 5.4ϫ10 6 Ϯ8.0ϫ10 6 cells (300 L) into the LV wall. The control group (nϭ10) received culture medium (300 L). Cell types were identified with vimentin and fast myosin. After 4 weeks, ventricular function was reassessed by echo. For histological analysis, heart tissue was stained with hematoxylin and eosin and immunostained for fast myosin.
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.
OBJECTIVETo compare the effect of the use of intermittent and continuous positive airway pressure in postoperative patients undergoing coronary artery bypass grafting.
METHODSThis 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.
RESULTSThe patient groups were homogeneous in relation to the several demographic and clinical variables. The values of pO 2 , pCO 2 and sO 2 were within normal limits and no signifi cant differences were found between the groups. Regarding respirometry, the groups showed signifi cant 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 signifi cantly higher frequency in patients undergoing CPAP. Patients undergoing Müller Resuscitator had a normal chest radiograph more frequently than did patients undergoing CPAP.
CONCLUSIONBoth devices were shown to be able to keep pO 2 , pCO 2 , and sO 2 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.
KEY WORDSIPPB, continuous positive airway pressure, physical therapy.
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