BACKGROUND: Previous research has demonstrated that bone marrow mesenchymal stem calls (BMSCs) differentiate into varying mesoderm-derived mesenchymal cells, such as myocardial cells.OBJECTIVE: To investigate the feasibility of construction of engineered myocardial tissues with polylactic-co-glycolic acid (PLGA) olymer and cardiomyocyte-like cells derived from BMSCs in vitro.METHODS: BMSCs were isolated from bone marrow of SD rats by density gradient cantrifugation. The third passage cells were induced with the culture medium including 5-aza for 4 weeks. After successful induction, the cells were trypsinized and suspended, then the cell suspension was added to the polylactic-co-glycolic acid square slowly and cultured in the incubator for 14 days. The morphological changes were observed before and after induction under phase contrast microscope. The cardiomyocyte-like cells were identified by immunofluorescanca staining. The naked eyes were used to observe the morphology of engineered myocardial tissues. The ultrastructures of the engineered myocardial tissues were viewed with a transmission electron microscope.RESULTS AND CONCLUSION: BMSCs of primary culture formed cell colonies at 14 days. The passaged cells were larger than those of primary culture. After induction by 5-aza, the cells presented long spindle and aligned in parallel. The expression of specific proteins of cardiac troponin Ⅰ (cTnl) in induced BMSCs was positive. Transmission electron microscopy showed that the engineered myocardial tissues had myofilaments, Z line-like substances. With PLGA and cardiomyocyte-like cells derived from BMSCs, the engineered myocardial tissues which resemble native cardiac tissues can be successfully constructed in vitro.

BACKGROUND: With the development of biotechnology, the electrophysiology of repairing heart tissues of myocardial infarction or myocardial hypertrophy by using bone marrow mesenchymal stem cell has become a hot spot. OBJECTIVE: To overview the research progress of cardiac electrophysiological characteristics after transplantation of induced differentiation of bone marrow mesenchymal stem cells into cardiomyocytes. METHODS: The databases of PubMed, Springer Link, Science Direct and CNKI were retrieved for papers published from January 2000 to October 2010 with the key words of bone marrow mesenchymal stem cells, cardiac/heart, electrophysiology/electrophysiological characteristics. The relevant articles concerning cardiac electrophysiological characteristics of induce differentiation and transplantation of bone marrow stem cells were collected. RESULTS AND CONCLUSION: Totally 208 papers have been searched. Preliminary screening by reading abstracts to exclude 162 papers that study purpose do not coincident with this review either contents duplicated, and internalized 46 papers at last. Bone marrow mesenchymal stem cells after induced differentiation and transplantation could improve heart function of animal experimental model and myocardial infarction or myocardial hypertrophy patients. Although the cardiomyocyte-like cells from bone marrow mesenchymal stem cells could help to improve heart function, the cardiac electrophysiological characteristics may be influenced by them.

Objective　To investigate the effects of magnetic stents on coronary restenosis after percutaneous transluminal coronary angioplasty (PTCA). Methods　Twenty dogs were randomly divided into the control and experimental groups, each with 10 dogs. The control group was given common Palmaz-stents in the 6-8 segment of left anterior descending coronary artery or in the 11-14 segment of the left circumflexus. The experimental group was given magnetic stents in the same parts of the coronary arteries. The dogs were not given antiplatelet or anticoagulant drugs before or after the operation. Six months later, the 20 dogs were subjected to coronary angiographies, and then were sacrificed. Three centimeter long segments of the target vessels were cut for pathological examination. Results　The degree of restenosis in 3 dogs of the control group was more than 50%, but none in the experimental group experienced restenosis. The average thickness of the tunica intima of the target artery was 2.98±0.56?mm in the control and 1.13±0.41?mm in the experimental group (P<0.05). Conclusion　Magnetic stents could have a significant preventive effect on coronary restenosis.