CD_(34)^+干细胞的分化及其在人工血管内皮化中的应用

Induction of differentiation of CD_ (34)^+ cells in vitro and application in endothelialization of blood vessel prostheses

目的 :探讨外周血、骨髓和脐血中 CD3 4 +细胞作为人工血管内皮化的种子细胞来源问题。方法 :采集犬外周血和骨髓及人脐血 ,经免疫磁珠分离出内皮细胞祖细胞 ,内皮细胞生长因子 (VEGF)诱导分化为内皮细胞并扩增 ,光镜、扫描电镜和免疫细胞化学鉴定 ;将培养细胞种植于人工血管 ,扫描电镜观察。结果 :经流式细胞仪测定 ,分离后的细胞中 CD3 4 +细胞 :外周血 (2 6 .30± 2 .4 2 ) %、骨髓 (4 1.84± 3.6 5 ) %、脐血 (74 .6 2± 4 .4 6 ) % ,骨髓和脐血中CD3 4 + 细胞数量明显多于外周血 ,且增殖、分化能力强 ;CD3 4 + 细胞培养 2周细胞长满瓶底并达到增殖高峰 ,细胞呈“铺路石”状排列。 因子 ,CD3 1免疫细胞化学染色均为阳性 ,透射电镜细胞胞浆内可见 W- P小体 ;扫描电镜下 ,内皮细胞平铺于人工血管表面 ,成单层排列 ,细胞排列无轴向性。结论 :外周血、骨髓和脐血经免疫磁珠分离系统可分离出 CD3 4 +细胞 ,CD3 4 +细胞经 VEGF诱导可定向分化为内皮细胞。骨髓和脐血 CD3 4 +细胞可作为人工血管内皮化的种子细胞来源。

Objective: To induce differentiation of CD 34+ cells from varying sources into epithelial cells for potential application of blood vessel prostheses. Methods: CD 34+ cells were isolated from canine peripheral blood and bone marrow or human umbilical cord blood by an immune magnetic cell sorting system. The isolated CD 34+ cells were induced to differentiate into endothelial cells in a liquid culture with VEGF. Endothelial cells were evaluated by immunocytochemistry and transmission electron microscopy. CD 34+ cells were seeded on PTFE prostheses, which were harvested and observed by electron microscopy. Results: The average isolated CD 34+ cells from peri- pheral blood, bone marrow and umbilical cord blood were (26.30±2.42)%, (41.84±3.65)% and (74.62±4.46)%, respectively. The number of CD 34+ cells increased with the culture duration and reached to the highest level at the 14th d. Immunostaining showed positive signal for CD31 in endothelial cells and positive for factor Ⅷ in cell culture. Transmission electron microscopy found Weibel-Palade bodies in the cytoplasm. Scanning electron microscopy demonstrated a single-layer of flat cells in the innermost layer of PTFE prostheses, and the cells were not of tropism. Conclusion: CD 34+ cells isolated from peripheral blood, bone marrow and umbilical cord blood can be induced into endothelial cells; bone marrow and umbilical cord blood can be used as the sources of seeding cells for endothelialization of prostheses.