ObjectiveTo review the role of stem cell niches in maintaining cardiac stem cells homeostasis, and to foresee its prospects. MethodsThe literature on cardiac stem cells niches was extensively reviewed. The roles of stem cell niches components, extracellular matrix, and secretory factors in maintaining cardiac stem cell homeostasis were analysed and reviewed. ResultsLots of experiments reveal that stem cell niches are able to delay the aging of cardiac stem cells, protect from external damage, keep stem properties, and improve the purity and quantity. However, the mechanism is not fully understood. ConclusionThe stem cell niches have a very bright application prospect in homeostasis, purification, and amplification for the cardiac stem cells, and it needs further study.
Objective To review the current status and problems in the developing scaffolds for the myocardial tissue engineering appl ication. Methods The l iterature concerning the myocardial tissue engineering scaffold in recent years was reviewed extensively and summarized. Results As one of three elements for tissue engineering, a proper scafold is veryimportant for the prol iferation and differentiation of the seeding cells. The naturally derived and synthetic extracellular matrix (ECM) materials aim to closely resemble the in vivo microenvironment by acting as an active component of the developing tissue construct in myocardial tissue engineering. With the advent and continuous refinement of cell removal techniques, a new class of native ECM has emerged with some striking advantages. Conclusion Through using the principle of composite scaffold, computers and other high-technology nano-polymer technology, surface modification of traditional biological materials in myocardial tissue engineering are expected to provide ideal myocardial scaffolds.
【Abstract】 Objective To investigate the expression of connexin 40 (Cx40) and hyperpolarization-activated cycl icnucleotide-gated cation channel 4 (HCN4) in rat bone marrow mesenchymal stem cells (BMSCs) cocultured with the sinoatrialnode (SAN) tissues in vitro, so as to evaluate the possibil ity of BMSCs differentiation into SAN cells. Methods BMSCs wereisolated from Sprague Dawley rats (aged 4-6 weeks, male or female) by the adhesive method and cultured; BMSCs at the 3rdpassage were marked with carboxyfluorescein succinimidyl ester, and then were incubated on 6-well culture plate; cell climingsl ices were prepared at the same time. SAN tissue was taken and cut into 0.3 cm × 0.3 cm mass, and then placed into 4℃ PBSsolution. The SAN tissue mass was cocultured with marked BMSCs at the 3rd passage for 3 weeks as the experimental group, andBMSCs at 3rd passage were cultured alone for 1 week as the control group. At 1, 2, and 3 weeks after coculture, the mean integratedabsorbance (MIA) values of Cx40 and HCN4 were measured by Image pro plus 5.0 through the method of immunohistochemistry,and the mRNA expressions of Cx40 and HCN4 were identified by real-time fluorescent quantitative PCR. Results TheMIA values of Cx40 and HCN4 in the experimental group were higher than that in the control group, showing significantdifferences (P lt; 0.01). In the experimental group, the expressions of Cx40 and HCN4 increased gradually with time. The longerthe culture time was, the higher the expressions of Cx40 and HCN4 were, showing significant differences (P lt; 0.05). The mRNAexpressions of Cx40 and HCN4 in the experimental group were significantly higher than those in the control group (P lt; 0.01); inthe experimental group, the mRNA expressions of Cx40 and HCN4 increased gradually with time, showing significant differencesbetween different time points (P lt; 0.05). Conclusion The expressions of Cx40 and HCN4 increase obviously after coculturingBMSCs with SAN tissue, indicating that BMSCs could differentiate into SAN cells by coculturing with SAN tissue in vitro.
Objective To review the current status and problems in developing cardiac biological pacemaker(CBP) by cell transplantation. Methods The l iterature over the past decade concerning CBP constructed through celltransplantation was reviewed and summarized. Results Experiments in vivo testified that the cell transplantation was feasible for CBP construction, and the transplantation of sinus atrial node cell and stem cell was still the predominant method for constructing CBP. However, such problems as difficult ampl ification of transferred cardio muscle cell, low success rate of CBP construction as well as unstable function of CBP make it lag behind the tremendous cl inical demands. The gene transfection technology might be one of the approaches to resolve these issues. Conclusion As one feasible method for CBP construction, the cell transplantation has a bright future in the cl inical appl ication and is worthy of further study.
Objective To establish an effective model of myocardial infarction in black goat so as to provide a safe, convenient and credible model of myocardial infarction for treatment and research. Methods Sixteen black goats were made chronic myocardial infarction by ligation of far end of left anterior descending coronary artery through incision below xiphoidprocess. Electrocardiogram(ECG) and serum myocardial enzymes were investigated before and after occlusion. Echocardiographic measurements were performed, and left coronary artery angiography was performed with digital subtraction angiography (DSA) before infarction and 6 weeks after infarction. The myocardial ultrastructure were observed. Results All goats survived more than 6 weeks. ECG showed ambulatory change, ST-segment elevated half an hour after occlusion and pathologic Q waves 6 weeks after infarction, CK-MB significantly increased. Echocardiographic indexes showed significant decrease of maximal peak A, percent wall thickening(WHT) and ejecting fraction (EF), increase ofend-systolic volume (ESV), end-diastolic volume (EDV), and dilation of left ventricle. DSA showed block or decrease of perfusion of far end of left anterior descending coronary artery. Conclusion It is safe, convenient and credible to establish model of myocardial infarction by ligation of far end of left anterior descending coronary artery through incision below xiphoidprocess in black goat.
ObjectiveBy comparing the difference between different stenosed degree of aortic valve in flow field uniformity and turbulent shear stress (TSS), to explore the relation between flow field uniformity and different stenosed degree of aortic valve, and probe the clinical value for deciding the operation timing, and analyze the possible role of TSS in the progress of the disease.MethodsThe flow field uniformity values and TSS in parasternal long axis plane and apical five cavity plane on each point were measured and calculated by pulse wave Doppler echocardiography technique for 33 patients with different stenosed degree of aortic valve.ResultsThere were significant difference between the different stenosed degree of aortic valve in maximal velocity difference(ΔV max )and TSS( P lt;0.05, 0.01). The more severe the aortic stenosis was, the worse the flow field uniformity was, the lower the TSS was.ConclusionsThere are significant difference between the patients of different stenosed degree of aortic valve in flow field uniformity. Flow field uniformity has important value in classifying the degree of aortic stenosis and deciding the timing of operation. The more severe the aortic stenosis is ,the lower TSS is. It can be thought that low TSS distribution has important role in pathological process of constriction in cardiovascular system diseases.