Zhang Ge, Nakamura Yasushiro, Wang Xiaohong, Hu Qingsong, Suggs Laura J, Zhang Jianyi
Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Tissue Eng. 2007 Aug;13(8):2063-71. doi: 10.1089/ten.2006.0013.
Stromal-derived factor 1alpha (SDF-1alpha) is a key stem cell homing factor that is crucial for mobilization of stem cells from bone marrow to peripheral blood and subsequent engraftment to the tissue of diseased organs. It has been reported that SDF-1alpha is transiently over-expressed in ischemic myocardium. Therefore, there may be a limited time window after acute myocardial infarction (AMI) during which stem cells are recruited to injured myocardium for repair. This study aimed at investigating whether controlled release of SDF-1alpha via a novel conjugated poly(ethylene glycol) (PEG) (PEGylated) fibrin patch at the infarct site would increase the rate of stem cell recruitment and offer potential therapeutic benefits. Recombinant mouse SDF-1alpha was covalently bound to the PEGylated fibrinogen as evidenced by immunoprecipitation and western blotting. The PEGylated fibrinogen, bound with recombinant mouse SDF-1alpha, was mixed with thrombin to form the PEGylated fibrin patch. The release kinetics of SDF-1alpha were detected in vitro using enzyme-linked immunosorbent assay. Using a mouse AMI model produced by a ligature on the left anterior descending coronary artery, a PEGylated fibrin patch bound with SDF-1alpha (100 ng) was placed on the surface of the infarct area of the left ventricle. Infarct size, left ventricular (LV) function, and the percentage of sca-1(+)/c-kit(+) cells within the infarct area were measured at days 7, 14, and 28 after AMI. In vitro results showed that SDF-1alpha was successfully bound to the PEGylated fibrin patch and can be released from the patch constantly for up to 10 days. Two weeks after infarction, the myocardial recruitment of c-kit(+) cells was significantly higher in the group treated with the SDF-1alpha PEGylated fibrin patch (n = 9) than in the AMI control group (n = 10) (p < 0.05; 11.20 +/- 1.71% vs. 4.22 +/- 0.96%, respectively). At day 28 post-AMI, unlike the control group, the group with the SDF-1alpha-releasing patch maintained stable release of SDF-1alpha concurrent with additional stem cell homing. Moreover, LV function was significantly better than in the control group. These data demonstrate that the PEGylated fibrin patch based SDF-1alpha delivery can improve the rate of c-kit(+) cell homing and improve LV function in hearts with postinfarction LV remodeling.
基质衍生因子1α（SDF-1α）是一种关键的干细胞归巢因子，对于将干细胞从骨髓动员至外周血并随后植入患病器官组织至关重要。据报道，SDF-1α在缺血心肌中短暂过度表达。因此，急性心肌梗死（AMI）后可能存在一个有限的时间窗，在此期间干细胞被募集至受损心肌进行修复。本研究旨在调查通过一种新型共轭聚乙二醇（PEG）（聚乙二醇化）纤维蛋白贴片在梗死部位控释SDF-1α是否会提高干细胞募集率并提供潜在的治疗益处。重组小鼠SDF-1α通过免疫沉淀和蛋白质印迹法证明与聚乙二醇化纤维蛋白原共价结合。将与重组小鼠SDF-1α结合的聚乙二醇化纤维蛋白原与凝血酶混合形成聚乙二醇化纤维蛋白贴片。使用酶联免疫吸附测定法在体外检测SDF-1α的释放动力学。利用左冠状动脉前降支结扎制备的小鼠AMI模型，将与SDF-1α（100 ng）结合的聚乙二醇化纤维蛋白贴片置于左心室梗死区域表面。在AMI后第7天、14天和28天测量梗死面积、左心室（LV）功能以及梗死区域内sca-1(+)/c-kit(+)细胞的百分比。体外结果显示，SDF-1α成功结合至聚乙二醇化纤维蛋白贴片，并可从贴片中持续释放长达10天。梗死两周后，用SDF-1α聚乙二醇化纤维蛋白贴片治疗的组（n = 9）中c-kit(+)细胞的心肌募集明显高于AMI对照组（n = 10）（p < 0.05；分别为11.20±1.71%对4.22±0.96%）。在AMI后第28天，与对照组不同，释放SDF-1α的贴片组在额外的干细胞归巢同时维持SDF-1α的稳定释放。此外，LV功能明显优于对照组。这些数据表明，基于聚乙二醇化纤维蛋白贴片的SDF-1α递送可提高c-kit(+)细胞归巢率，并改善梗死后LV重塑心脏的LV功能。
