| Background:Neural remodeling refers to hyperinnervation and uneven distribution of sympathetic nerve fibers around the border of infarcted myocardium.Unbalanced neural remodeling could cause fatal ventricular arrhythmia(VA) and increase mortalities but few strategies are available to suppress the sympathetic remodeling after acute myocardial infarction (MI).Schwann cells have the potential to stimulate nerve regeneration. Numerous reports demonstrated that Schwann cells exert their function through paracrine and cell contact.Moreover,Schwann cells help protein expression which is essential for basal lamina formation.Therefore,this study aims at evaluate the Schwann cells' neurogenesis abilities and explore Schwann cells' potential to balance nerve remodeling.Methods:Immediately after creation of MI,the rats were randomized into cell transplantation(n=80) and control groups(n=72).Schwann Cells(SCs) were obtained from sciatic nerves.The cells was cultured on tiny glass sheet and stained with SIO0 which is a surface marker of $chwann cells.Release of nerve growth factors(NGF) and vascular endothelial growth factor(VEGF) fromSchwann cells was detected by using ELISA.5×10~6 cells of second passage were intramyocardially injected into the infarcted region.Series histological and immunohistochemical studies were performed at 24 hours, 1 and 2 weeks after cell transplantation.In immunohistochemical studies, SIOO,BrdU,and CD68 staining were performed.As for immunofluorescence study,tyrosine hydroxylase(TH),acetycholinesterase enzyme(AChE),and growth associated protein 43(GAP43) staining were performed.NGF,VEGF, GAP 43,connexin 43,and laminin expression were detected by using western blot. Results:Comparison of S100 positive cells between control and cell transplantation group.Few cells were stained with S100 24 hours after myocardial infarction in control group,and more cells expressed both S100 and BrdU were detected in cell transplantation group.Growing number of S100 positive cells was observed in both groups with significantly more S100 positive cells in cell transplantation group.The number of transplanted BrdU positive SCs dropped sharply with elapse of time.The expressions of NGF,VEGF,GAP 43,connexin 43,laminin in myocardium were of no significant difference 24 hours after cell transplantation.But the above protein expressions in one week and two weeks were significantly higher in Schwann cell group than in control group.At 24 hours,transplanted SCs significantly attracted macrophage.But no differences of macrophage counting were noted between two groups.At 24 hours,one week,and two weeks,density of sympathetic nerves,parasympathetic nerves,and new-born nerve fibers increased in both groups,but SCs transplantation contributed to the increment of parasympathetic/sympathetic ratio at two weeks after MI.But SCs transplantation didn' t restore the damaged heart function.Conclusions:Transplanted SCs secreted nerve growth factor,attract macrophage,stimulate expression of laminin and connexin 43,and enhance the ratio of parasympathetic/sympathetic.SCs transplantation might be a promising cell-based antiarrhythmic therapy to balance sympathetic nerve sprouting MI. Background:Currently,surgical intervention is still the most important option for the treatment of heart valvular diseases.However,although frequently adopted,mechanical valves and bioprosthetic valves have their shortcomings.As a result,autologous heart valve construction catches researchers' eyeballs.Previous studies demonstrated that mesenchymal stem cells are ideal candidates to be seeded on scaffold for valve construction.But the aging effects on the in vitro biological properties of bone marrow-derived mesenchymal stem cells(BMSCs) for construction of tissue engineered heart valves are unclear yet.The aim of this study was to compare in vitro biological properties of BMSCs so as to provide theoretical basis for seed cell selection for autologous heart valve construction.Methods:BMSCs were taken from teenagers(younger than 18 years) with congenital heart diseases,middle(18-40 years) and elderly patients(over 40 years) with valvular diseases.Proliferative abilities were compared among the three groups by using colony-forming unit counting and growth curves(5-bromo-2'-deoxyuridine assay).The BMSCs morphology among three groups was compared as well.FACS flow cytometry was employed for phenotype analysis of BMSCs from three groups.Cell differentiation (differentiation into endothelial cells,adipose cells,and osteoblasts),in vitro release of vascular endothelial growth factor(VEGF) and migratory abilities were compared as well.Results:Compared with teenager group and middle age group,BMSCs can be separated successfully from bone marrow of aged group.The morphological comparison revealed no significant differences.No significant differences in terms of cell surface marker wereResults:Compared with teenger group and middle age group,BMSCs can be separated successfully from bone marrow of aged group.The morphological comparison revealed no significant differences.No significant differences in terms of cell surface marker were noted between aged and non-aged groups by using FACS flow cytometry. Colony-forming unit counting in teenage group(32±3) was significantly greater than that in middle age group(26±5,p<0.05) and aged group(19±5,p<0.05) and significantly higher counting was observed in middle age group than in aged group (p<0.05).Growth curves presented similar trends in which cells' proliferative abilities in aged group decreased significantly(P<0.05) while no differences were noted between the two non-aged groups.The differentiation potential to endothelial cells,osteoblasts and adipocytes,VEGF release abilities and migratory abilities differed significantly between aged group and non-aged groups(p<0.05).But no differences were noted between the two non-aged groups.Conclusion:BMSCs from old patients with heart valve diseases could be harvested and expanded successfully.However,the proliferative and differentiation properties of aged cells,as well as migratory abilities,are significantly impaired.Therefore,construction of autologous tissue engineered valves for the old patients should be performed with cautions.
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