NEW TREATMENT FOR MYOCARDIAL INFARCTION BY XENO-FETAL CARDIOMYOCYTE TRANSPLANTATION

背景资料。胚胎心肌细胞同种异体移植已成功进行。在本研究中，我们试图通过CTLA4-Ig基因转移阻断CD28/B7共刺激通路，将大鼠胚胎心肌细胞移植到小鼠心脏。以表达CTLA4-Ig的腺病毒载体(AdCTLA)感染DA大鼠胎鼠心肌细胞，将其直接注射入C3H/He小鼠正常心肌(n=15)。将感染β-Gal的腺病毒载体(AdRL)的细胞和未感染的细胞注射到另外30只小鼠体内作为对照。用X-Gal染色或抗CTLA4-Ig抗体免疫染色检测AdRL或AdCTLA感染心肌细胞的百分率。分别于异种移植后2周、4周、8周处死小鼠。用抗大鼠心房利钠肽(ANP)和抗CTLA4-Ig抗体进行免疫组织化学染色，观察移植心肌细胞的存活情况。X-Gal染色和免疫染色显示，在感染AdCTLA或AdRL后3d，10moi、50moi和100moi的感染率分别约为30%、65%和50~70%。AdCTLA感染的小鼠心肌细胞均表达CTLA4-Ig，移植后存活至8周。但在异种移植后2周仍未检测到感染AdRL的心肌细胞和未感染的心肌细胞。AdCTLA和AdRL成功地感染了胎儿心肌细胞，腺病毒介导的CTLA4-Ig表达延长了异种移植胎儿心肌细胞的存活时间。

Background. Experimental allografting of fetal cardiomyocytes has been performed successfully. In this study, we attempted to transplant rat fetal cardiomyocytes into the hearts of mice by blocking the CD28/B7 co-stimulatory pathway via CTLA4-Ig gene transfer.Methods. Fetal cardiomyocytes derived from Dark Agouti (DA) rat were infected with CTLA4-Ig-expressing adenovirus vectors (AdCTLA) and injected directly into the normal myocardium of C3H/He mice (n=15). For control, cells infected with β-Gal-expressing adenovirus vector (AdRL) and cells without infection were injected into additional mice (n=30). The percentages of cardiomyocytes infection by AdRL or AdCTLA were estimated by X-gal staining or immunostaining with anti-CTLA4-Ig antibody. Mice were killed at 2 (n=5), 4 (n=5), and 8 (n=5) weeks after xenotransplantation. Transplanted fetal cardiomyocytes were examined for survival by immunostaining with anti-rat artial natriuretic peptide (ANP) and anti-CTLA4-Ig antibodies.Results. X-gal staining and immunostaining showed infection to be approximately 30% at 10 MOI, 65% at MOI 50, and 50〜70% at MOI>100, 3 days after infection with AdCTLA or AdRL.The cardiomyocytes infected with AdCTLA expressed CTLA4-Ig and survived to 8 weeks after xenotransplantation in all of these mice. However, cardiomyocytes infected with AdRL and non-infected cells were not detected even 2 weeks after xenotransplantation.Conclusion. Fetal cardiomyocytes were successfully infected by AdCTLA and AdRL.Survival of xenografted fetal cardiomyocytes is prolonged by adenovirus-mediated CTLA4-Ig expression.