Since the concept of regenerative medicine has emerged, the transplantation of stem cells to the heart has shown to play an important role in myocardial regeneration. However, we still know very little about the benefits of stem cells transplantation (SCT) on the cardiac function of dogs with chronic Chagas disease.

Therefore, this study was conceived to evaluate the short-term changes in M-mode echocardiogram 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 ficoll gradient. It was then obtained a concentrate of mononuclear cells (mean concentration 35 million cells). After processing the 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 (determined by fluoroscopy and angiocardiogram). Cells were delivered in the right coronary artery following insertion of the catheter and balloon inflating. The following parameters were assessed: internal diameter of right ventricle (IDRV), internal diameter of left ventricle in systole (IDLVs) and diastole (IDLVd), interventricular septal thickness in systole (IVSTs) and diastole (IVSTd), left ventricle free wall in systole (LVFWs) and diastole (LVFWd), shortening fraction (SF), and ejection fraction (EF). All dogs underwent echocardiographic evaluation prior (M0) to stem cells transplantation and after 24 hours (M1), 1 week (M2), 2 weeks (M3), 1 month (M4), and 2 months (M5).

The following results were obtained (M0-mean±SD-M5-mean±SD): IDRV (0.66±0.19-1.09±0.36), IDLVs (2.03±0.37-1.76±0.15), IDLVd (2.99±0.15-2.99±0.09), IVSTs (1.01±0.20-1.05±0.08), IVSTd (0.69±0.07-0.75±0.07), LVFWs (1.07±0.11-1.15±0.30), LVFWd (0.85±0.15-0.73±0.10), SF (32.33±9.29-41.33±4.04), and EF (61.00±13.07-73.33±5.03). Despite some parameters did change along the moments of evaluation, when data was submitted to ANOVA, no statistical differences were determined.

Results allowed concluding that SCT produce no changes in M-mode echocardiogram up to 2 months after transplantation into the right coronary artery of dogs with chronic Chagas cardiomyopathy. One could assume that the route of delivery of cells, the short period of evaluation, and also the advanced chronic stage of the disease could have played a role in the impairment of myocardial regeneration.