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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.
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Magnesium and its alloy are used for the most potential endovascular stent material due to their excellent mechanical capabilities, adjustable corrosive properties, the little side effects of the materials and their degradation products. The in vito degradation rate of the current magnesium and its alloy as endovascular stent is very quickly so that the artery is not supported long enough to prevent negative remodeling. This review detailed the approach to enhance the corrosion resistance, in vitro corrosion rate measurement of magnesium and its alloy, as well as the in vito corrosion research when as the endovascular stents.
Subject(s)
Humans , Alloys , Chemistry , Biocompatible Materials , Corrosion , Magnesium , Chemistry , Materials Testing , StentsABSTRACT
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.
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Objective To investigate the preventive effect of magnetic stent on coronary restenosis after percutaneous arterial stenting.Methods Twenty rabbits were divided randomly into 2 groups.Bare stent(BS group,n=10)or magnetic stent(MS group,n=10)wasimplanted in the left iliac artery of the rabbits of the 2 groups,respectively.Aspirin (25mg,qd )was administered orally to the rabbitsof both groups from 3 days before stenting until the rabbits were executed.Unfractionated heparin (2500u,qd) was delivered subcuta-neously after stenting for 7days.Five rabbits of each group were randomly selected to be executed at 7 or 30 days.Stmctural changesin the iniured arteries were studied by optical microscopey,transmissive electronic microscopey and immunohistochemistry.ResultsAt 7 days.more myofibroblasts were found migrating from adventitia to tunica media and intima in BS group than in MS group.insidethe media and intima,large amount of smooth muscle cells of synthetic type were observed.At 30 days after stenting,in magnetic group,most uascular smooth musele cells(SMCs)under the intima had transformed to contractile type and only little extracellular matrix(ECM)was observed around the SMCs;whereas,in BS group,the SMCs remained to be synthetic type and large amount of ECM wasobserved around the SMCs.which was composed mainly of proteoglycans and glycoproteins. Conclusions Magnetic stent caninhibit proliferation and migration of SMCs and reducing the production of ECM.and therefore,may prevent restenosis after coronarystenting.
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Objective We aimed to investigate whether magnetic stent has preventive effect on in-stent restenosis by observing expressions of matrix metalioproteinase (MMP)2,MMP9,tissue inhibitor of matrix metalloproteinase (TIMP)1 and TIMP2 after balloon angioplasty,bare and magnetic stent implantation in rabbits.Methods Rabbits underwent balloon angioplasty,bare and magnetic stent implantation in the left iliac arteries.The changes of MMPs and TIMPs were examined at various time points in the injured arteries using the methods of zymography,Western blot analysis,reverse transcription-polymerase chain reaction (RT-PCR) and morphometric analysis.Results Balloon angioplasty group (BA) and magnetic stent group (MS) showed lower intrinsic gelatinolytic activity and higher expression of TIMPs with less intimae hyperplasia;Whereas bare stent (BS) group exhibited higher intrinsic gelatinolytic activity and lower expression of TIMPs with significant intimae hyperplasia.Conclusion Magnetic stent probably has preventive effect on in-stent restenosis by changing intrinsic matrix metalloproteinases activity and expression of TIMPs.