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.
摘要: 目的 探討自體骨髓間充質干細胞(MSCs)小腸黏膜下層(SIS)支架復合物移植于陳舊性心肌梗死區域后細胞的存活、支架的降解情況及其對心功能的影響。 方法 將16只黑山羊按隨機數字表法分為兩組，每組8只。實驗組：建立心肌梗死模型，抽取自體骨髓,經體外分離MSCs,進行培養、傳代、BrdU標記、與SIS支架復合，并于心肌梗死6周時將MSCs-SIS復合物補片移植至陳舊性心肌梗死區；對照組：建立心肌梗死模型。于移植后6周行超聲心動圖、HE染色及免疫組織化學檢測。 結果 MSCs-SIS植入心肌梗死區2周時在補片區可見大量炎性細胞浸潤；6周時淋巴細胞浸潤消失，SIS部分降解，移植區見大量移植細胞存活。MSCs-SIS植入體內后6周時，實驗組每搏輸出量(42.81±4.91 ml vs. 37.06±4.75 ml)、射血分數(59.20%±5.41% vs. 44.56%±4.23%)、室壁增厚率（54.51%±8.60% vs. 43.36%±8.91%）、舒張期E峰 (54.85±6.35 cm/s vs. 43.14±4.81 cm/s)顯著高于對照組(Plt;0.05)，左心室收縮期末容積(29.75±5.98 ml vs. 46.25±6.68 ml)、舒張期末容積(72.55±8.13 ml vs. 83.31±8.61 ml)顯著低于對照組(Plt;0.05)。 結論 SIS作為支架移植MSCs有利于移植細胞存活，對陳舊性心肌梗死后心功能有明顯的改善作用。
【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.
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.
