Cardiomyogenic differentiation of human bone marrow mesenchymal cells: Role of cardiac extract from neonatal rat cardiomyocytes.

Bone marrow mesenchymal stromal cells (BM-MSCs) with regenerative potential have been identified in heart. Whether these cells become new cardiac lineage cells by phenomena of transdifferentiation or fusion is also being investigated. Although, these mechanisms give cardiomyocytes, it has to be considered that MSCs transplantation could carry out ossification and calcification processes. An alternative might be the use of myocytes; however, the problem is the arrythmia. For those reasons, is that we investigated how to obtain cardiomyocyte-like cells from human MSCs (hMSCs). The aim of the present work was to evaluate a nuclear reprogramming of the hMSCs by a neonatal rat cardiomyocytes extract (EX) using Streptolysin O (SLO) treatment. hMSCs treated with 57.5ng/ml SLO presented ball-like, stick-like and myotube-like morphology. In the absence of cardiomyogenic stimuli, hMSCs expressed markers of cardiac phenotype-like sarcomeric alpha-actinin, connexin-43 and GATA-4. However, when hMSCs were treated with SLO+EX or 10 microM of 5-azacytidine (5-AZA), the expression of these markers were significantly increased and furthermore, expressed SERCA-2, cardiac Troponin I, beta-MyHC, desmin, MLC-2a and MLC-2v thus showing the phenotype of mature cardiomyocytes. PCR analysis showed that cardiomyocyte-related genes, such as beta1-adrenergic receptor (beta1-AR), MLC-2a and cardiac Troponin T, were expressed after SLO+EX treatment like with 5-AZA. We concluded that the extract of neonatal rat cardiomyocytes could promote a nuclear modification of hMSCs to cardiomyogenic-like cells differentiation. Since the 5-AZA treatment appears to be genotoxic and taking into account the obtained results, the nuclear reprogramming by cell extract may be an approach leading to the identification of soluble factors that drives the reprogramming.

Interleukin-1 beta, transforming growth factor beta 1, prostaglandin E2, and fibronectin levels in the conditioned mediums of bone marrow fibroblast cultures from lung and breast cancer patients.

We analyzed the ability of the bone marrow (BM) stromal cells to achieve confluence and their proliferative capacity in BM primary cultures from 30 untreated lung cancer patients (LCP), 27 breast cancer patients (BCP), and 30 normal controls (NC) when these confluent cells were induced to proliferate following four continuous subcultures. Moreover, we evaluated the production of interleukin-1 beta (IL-1beta), transforming growth factor beta 1 (TGF-beta1), fibronectin, and prostaglandin E2 (PGE2) by pure fibroblasts (fourth passage). A fibroblast colony-forming units (CFU-F) assay was used to investigate the proliferative and confluence capacity. Levels of IL-1beta, TGF-beta1, and fibronectin in conditioned mediums (CM) of fibroblast cultures were measured by enzyme-linked immunosorbent assay (ELISA) kit and PGE(2) by radioimmunoassay (RIA) kit. Confluence was achieved in the 60% of LCP and 78% of BCP primary cultures compared with 100% of NC, and only fibroblasts from seven LCP and six BCP cultures had the capacity to proliferate following four subcultures. Levels of IL-1beta were below 10 pg/ml in both patient groups, while NC had a mean value of 5882.57+/-221.61 pg/ml. Levels of TGF-beta1 in BCP were lower than NC values ( P<0.05). LCP and BCP had significantly decreased levels of fibronectin when compared to NC values ( P<0.05 and P<0.01, respectively). Levels of PGE2 in LCP were higher compared to NC ( P<0.01). In conclusion, BM fibroblasts from LCP and BCP presented a defective proliferative and confluence capacity, and this deficiency may be associated with the alteration of IL-1beta, TGF-beta1, fibronectin, and PGE2 production.