Terapia celular com células mononucleares de medula óssea cultivados em meio basal de endotélio na hipertensão arterial sistêmica em ratos

Abstract

Systemic arterial hypertension (SAH), defined as a systolic blood pressure ≥140 mmHg and diastolic blood pressure ≥90 mmHg, affects around 1/5 of entire world population, being a huge public health problem. Although several advances have been achieved to understand the pathophysiological base of the essential arterial hypertension, which represents 90-95% of cases of SAH, the complete framework of pathogenesis is not completely understood, deserving yet several efforts of basic and clinical investigative research. Despite of several and successful therapeutic strategies based mainly in pharmacological approach, essential hypertension has not yet a definitive cure, making imperative new therapy searching. The aim of the present study was to investigate the effects of mononuclear cell cultivated in endothelial basal medium (EBM) on arterial pressure (AP) levels as a possible therapeutic strategy. Mononuclear cells (MNC) were extracted from tibiae and femurs of 16 syngeneic donor male 16-weeks old SHRs, and then MNC were plated on culture dishes coated with human fibronectin and cultured in endothelial cell basal medium-2 supplemented with growth factors for two weeks. Fibroblast used like control cells were extracted from skin of the same male SHR used. EBM cultivated mononuclear cells (n=14) or fibroblast (n=11) labeled with CM-Dil cell tracker were injected intravenously (1 x 106cells/rat, i.v.) in 16-weeks old female receptor SHRs. Age-matched female SHRs (control group; n=14) have received vehicle. Indirect AP was recorded before and after transplantation by means of tail occlusion method. At the 15° day, after previous canulation (24 hs), all animals had their AP recorded during one hour in a computerized data analysis system (sampling rate of 1000Hz). The direct arterial pressure signal was analyzed by mono- or bivariate autoregressive spectral analysis. At the end, under anesthesia, systemic endothelial function was assessed by measuring the vasodepressor responses to acetylcholine and sodium nitropussiate. After sacrifice, absolute and relative heart weight was measured. No significant differences were observed in mean AP of distinct groups (151.12±4.58mmHg for EBM cultivated MNC group, 151.82.±4.23mmHg for fibroblast group and 146.83±3.91mmHg for control group, p=non significant) as well as in spectral parameters. Interestingly, the baseline heart rate of animals transplanted with fibroblasts was lower than those observed in other groups (340.33±10.67bpm*# fibroblast group, 369.96±4.57bpm for EBM-cultivated MNC group and 374.47±5.55bpm for control group, p<0,05 * fibroblast versus control e #fibroblast versus EBM-MNC group). Spontaneous baroreflex sensitivity measured by bivariate spectral analysis showed an improvement in the fibroblast group 0.85±0.04ms/mmHg# fibroblast group, 0.46±0.03ms/mmHg in control group and 0.41±0.04 in EBM-MNC group, p <0.05 #fibroblast versus EBM-MNC). However, systemic endothelial function did not differ between groups. Absolute and relative heart weight did not differ among groups. These results indicate that EBM-cultivated mononuclear cell transplantation is not effective to reduce arterial blood pressure and heart rate in SHR, even though fibroblasts improve heart rate and spontaneous baroreflex sensibility.