Identification of a suitable cell source combined with an appropriate 3D scaffold is an essential prerequisite for successful engineering of skeletal tissues. Both osteogenesis and angiogenesis are key processes for bone regeneration. This study investigated the vascularization potential of a novel combination of human dental pulp stromal cells (HDPSCs) with 45S5 Bioglass® scaffolds for tissue-engineered mineral constructs in vivo and in vitro. 45S5 Bioglass scaffolds were produced by the foam replication technique with the standard composition of 45 wt% SiO2, 24.5 wt% Na2O, 24.5 wt% CaO, and 6 wt% P2O5. HDPSCs were cultured in monolayers and on porous 45S5 Bioglass scaffolds under angiogenic and osteogenic conditions for 2–4 weeks. HDPSCs expressed endothelial gene markers (CD34, CD31/PECAM1, and VEGFR2) under both conditions in the monolayer. A combination of HDPSCs with 45S5 Bioglass enhanced the expression of these gene markers. Positive immunostaining for CD31/PECAM1 and VEGFR2 and negative staining for CD34 supported the gene expression data, while histology revealed evidence of endothelial cell-like morphology within the constructs. More organized tubular structures, resembling microvessels, were seen in the constructs after 8 weeks of implantation in vivo. In conclusion, this study suggests that the combination of HDPSCs with 45S5 Bioglass scaffolds offers a promising strategy for regenerating vascularized bone grafts.

BackgroundMesenchymal stem cells (MSCs) are promising cells for cardiovascular regenerative medicine. However, their potential may be limited, because of their restricted cardiovascular differentiation potential and decline in their number and functional characteristics with increasing donor age. We have previously shown that rat fetus heart harbors primitive MSCs and administration of these cells improved left ventricular (LV) function after ischemia/reperfusion injury in rats. To evaluate their potential as a new cell type for clinical cardiovascular cell therapy, we have undertaken this study on the isolation and characterization of human fetal cardiac MSCs (hfC-MSCs).MethodsMSCs were isolated from the heart of five 14-16-week-old aborted human fetuses and studied for their growth characteristics, karyotypic stability and senescence over successive passages, expression of mesenchymal and embryonal markers by flow cytometry and immunocytochemistry, constitutive expression of cardiovascular genes by RT-PCR, differentiation into cells of the cardiovascular lineage and their immunomodulatory properties.ResultsThe hfC-MSCs grew as adherent monolayer with spindle shaped morphology and exhibited rapid proliferation with an average population doubling time of 34 hours and expansion to up to more than 80 population doublings with maintenance of a normal karyotype and without senescence. Immunophenotyping showed that they had similar phenotype as human bone marrow mesenchymal stem cells (hBM-MSCs) expressing CD73, CD90, CD105 and lacking expression of CD31, CD34, CD45, HLA-DR. However, hfC-MSCs expressed significantly higher levels of CD117 and SSEA-4 compared to hBM-MSCs. In addition, hfC-MSCs expressed the embryonal markers Oct-4, Nanog and Sox-2 as compared to hBM-MSCs. Further, hfC-MSCs had significantly higher expression of the cardiovascular genes viz. ISL-1, flk-1, GATA-4, NKX2.5 and MDR-1 as compared to hBM-MSCs, and could be differentiated into major cardiovascular cells (cardiomyocytes, endothelial cells, smooth muscle cells). Interestingly, hfC-MSCs markedly reduced T-lymphocyte proliferation with an increased secretion of TGF-β and IL-10.ConclusionsOur results show that human fetus heart is a novel source of primitive MSCs with cardiovascular commitment which may have a potential therapeutic application in cardiovascular regenerative medicine.

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Human bone marrow mesenchymal stem cells (HBMSCs) has been the gold standard for bone regeneration. However, the low proliferation rate and long doubling time limited its clinical applications. This study aims to compare the bone tissue engineering efficacy of human dental pulp stem cells (HDPSCs) with HBMSCs in 2D, and 3D anorganic bone mineral (ABM) coated with a biomimetic collagen peptide (ABM-P-15) for improving bone-forming speed and efficacy in vitro and in vivo. The multipotential of both HDPSCs and HBMSCs have been compared in vitro. The bone formation of HDPSCs on ABM-P-15 was tested using in vivo model. The osteogenic potential of the cells was confirmed by alkaline phosphatase (ALP) and immunohistological staining for osteogenic markers. Enhanced ALP, collagen, lipid droplet, or glycosaminoglycans production were visible in HDPSCs and HBMSCs after osteogenic, adipogenic and chondrogenic induction. HDPSC showed stronger ALP staining compared to HBMSCs. Confocal images showed more viable HDPSCs on both ABM-P-15 and ABM scaffolds compared to HBMSCs on similar scaffolds. ABM-P-15 enhanced cell attachment/spreading/bridging formation on ABM-P-15 scaffolds and significantly increased quantitative ALP specific activities of the HDPSCs and HBMSCs. After 8 weeks in vivo implantation in diffusion chamber model, the HDPSCs on ABM-P-15 scaffolds showed extensive high organised collagenous matrix formation that was positive for COL-I and OCN compared to ABM alone. In conclusion, the HDPSCs have a higher proliferation rate and better osteogenic capacity, which indicated the potential of combining HDPSCs with ABM-P-15 scaffolds for improving bone regeneration speed and efficacy.

For cell based myocardial repair, a reliable and selective enrichment strategy of the cardiac precursor cells is crucial. Herein, we describe a modified approach which is economical and potent prototype of a cardiac precursor nanoprobe called GloTrack. It functions as a cell label and tracking agent. GloTrack constitutes cardiac specific antibodies-SIRPA and KDR that are bound to the surface of PEG coated SPION, which aids in the segregation of cardiac precursor cells from cardiac/non cardiac origin. We aimed to characterize its physical attributes for size (CLSM, TEM, SEM, Zetasizer), labeling efficiency (FACS), topology (AFM) and surface charge (Zeta potential). In addition, we determined it's in vivo distribution through MRI. The results establish GloTrack as a negatively charged, 900 nm size on an average with a variable topology, 99% labeling efficiency, having a uniform distribution of SIRPA+/KDR+, and has the feasibility of tracking in vivo using 7T MRI.

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