The effect of allogenic intravenous transplantation of placenta-derived MSC in rats with myocardial infarction
Myocardial infarction keeps a leading position in cardiovascular disease. Currently, the therapy after myocardial infarction is insufficient and non-healing. Recently, regenerative approaches are gaining more attention, including the transplantation of stem and progenitors cells. We performed the preclinical study of the allogeneic transplantation of placenta-derived MSC of fetal origin in rats with myocardial infarction. A month after the injection of placenta-derived MSC, rats were sacrificed and hearts were fixed in formalin, embedded in paraffin, and cut into section with 5mkm step. For analysis 15 sections were taken from each rat’s heart and risk zone was identified. Percentage of fibrosis was calculated as mean for all sections. The rats with administered cells (in total 16 rats, 250 sections) had the lower percentage of fibrous tissue in the scar than rats in the control group, n=9 (FIG. 1). According to the cardiogram, there was a complete restoration of the contractile function of the myocardium in animals that were administered with cells. The transplanted placenta-derived MSCs grafted into the heart, lungs, spleen, and liver of rats. The higher cardiomyocyte density in animals received PDMSCs confirmed also by the significantly lower cross-sectional area of the cardiomyocytes in group of animals with administered cells than in animals from the control group (FIG. 2), and consistent with the data on the lack of a difference in the cardiomyocyte and intercellular space ratio between control and experimental groups. Also, the absence of edema and the preventive effect of PDMSCs on the hypertrophy in heart tissues is confirmed by a lower relative weight of the heart in animals received cells compared to intact ones. Thus, in the term of this study, we showed a positive effect of systemic administration of allogeneic placenta-derived MSCs in rats after MI.
Algorithm for calculating the percentage of fibrous tissue in the risk area: counting the number of pixels that refer to the undamaged muscle tissue and for fibrosis individually. Calculation of the percentage of fibrous tissue by the formula: F * 100 / (M + F), where M and F are the number of pixels per muscle tissue and fibrosis, respectively.
Percentage of fibrous tissue in the risk zone of myocardium in intact rats with MI is higher than in rats with administered cells
Injected allogeneic PDMSCs prevent the hypertrophy of cardiomyocytes after MI in rats.
A lower heart weight in rats with administered cells indicates the lack of edema.