Evaluation of Mitral and Tricuspid Flow in Dogs with Chagasic Cardiomyopathy after Stem Cells Transplantation
Under appropriate conditions, stem cells have the ability to differentiate into cardiac myocytes and endothelial cells. However, it is not known exactly if stem cells transplantation (SCT) can really impede deterioration or restore cardiac function in dogs with damaged myocardium. Several studies have been performed to determine the benefits of SCT in human beings and animals. Dogs with chagasic cardiomyopathy develop an important diastolic impairment due to fibrosis and the role of SCT in diastolic function of such dogs is still not known. Thus, this study aimed at assessing the short-term changes in atrioventricular flows of dogs with Chagas cardiomyopathy. For such, three adult female mongrel dogs (mean weight 10.7 kg) with chronic Chagas cardiomyopathy were submitted to autologous SCT. Prior to the study, all animals underwent serological evaluation for Chagas disease. To allow bone marrow aspiration, the dogs were anesthetized with levomepromazine and sevoflurane. Twenty-five milliliters of bone marrow were collected. The aspirate was centrifuged several times in ficol gradient. It was obtained a concentrate of mononuclear cells. Each dog was individually placed on a hemodynamic table, equipped with fluoroscopy device. Dogs were anesthetized again and a Judkins right catheter was inserted through the right femoral artery until it reached the aortic valves. Cells were delivered in the right coronary artery following insertion of the catheter and balloon inflating. The following parameters were measured: peak velocity of mitral E-wave (PVME), peak velocity of mitral A-wave (PVMA), peak velocity of tricuspid E-wave (PVTE), and peak velocity of tricuspid A-wave (PVTA). The relation between PVME and PVMA, as well as the relation between PVTE and PVTA were also calculated. All dogs were echocardiographically evaluated prior (M0) to SCT, and after 24 hours (M1), 1 week (M2), 2 weeks (M3), 1 month (M4), and 2 months (M5). The basal echocardiogram revealed inversion of mitral E:A waves, characterizing an abnormal ventricular relaxation.
The following results were observed (M0-mean±SD-M5-mean±SD): PVME (0.52±0.08-0.45±0.04), PVMA (0.65±0.18-0.66±0.07), PVME/PVMA (0.81±0.10-0.67±0.01), PVTE (0.34±0.14-0.42±0.11), PVTA (0.56±0.16-0.59±0.13), PVTE/PVTA (0.60±0.14-0.72±0.11). Despite some variations were observed along the moments of evaluation, when data was submitted to ANOVA, no statistical differences were determined.
Results allowed concluding that SCT leads to no alterations in mitral and tricuspid flows up to 2 months after transplantation into the right coronary artery of dogs with Chagas disease. Moreover, the pattern of abnormal ventricular relaxation remains unaltered after this time. The chronic stage of the disease, associated to a high degree of myocardial fibrosis could have contributed for these data. It is also likely that the route of cell administration and the short period of evaluation played a role in the results.