Sueblinvong Viranuj, Loi Roberto, Eisenhauer Philip L, Bernstein Ira M, Suratt Benjamin T, Spees Jeffrey L, Weiss Daniel J
Department of Medicine, University of Vermont College of Medicine, Burlington, Vermont 05405, USA.
Am J Respir Crit Care Med. 2008 Apr 1;177(7):701-11. doi: 10.1164/rccm.200706-859OC. Epub 2007 Dec 6.
Recent studies have suggested that both embryonic stem cells and adult bone marrow stem cells can participate in the regeneration and repair of diseased adult organs, including the lungs. However, the extent of airway epithelial remodeling with adult marrow stem cells is low, and there are no available in vivo data with embryonic stem cells. Human umbilical cord blood contains both hematopoietic and nonhematopoietic stem cells, which have been used clinically as an alternative to bone marrow transplantation for hematologic malignancies and other diseases.
We hypothesized that human umbilical cord blood stem cells might be an effective alternative to adult bone marrow and embryonic stem cells for regeneration and repair of injured airway epithelium.
Human cord blood was obtained from normal deliveries at the University of Vermont. Cultured plastic adherent cells were characterized as mesenchymal stem cells (MSCs) by flow cytometry and differentiation assays. Cord blood-derived MSCs (CB-MSCs) were cultured in specialized airway growth media or with specific growth factors, including keratinocyte growth factor and retinoic acid. mRNA and protein expression were analyzed with PCR and immunofluorescent staining. CB-MSCs were systematically administered to immunotolerant, nonobese diabetic/severe combined immunodeficiency (NOD-SCID) mice. Lungs were analyzed for presence of human cells.
When cultured in specialized airway growth media or with specific growth factors, CB-MSCs differentially expressed Clara cell secretory protein (CCSP), cystic fibrosis transmembrane conductance regulator (CFTR), surfactant protein C, and thyroid transcription factor-1 mRNA, and CCSP and CFTR protein. Furthermore, CB-MSCs were easily transduced with recombinant lentiviral vectors to express human CFTR. After systemic administration to immunotolerant, NOD-SCID, mice, rare cells were found in the airway epithelium that had acquired cytokeratin and human CFTR expression.
CB-MSCs appear to be comparable to MSCs obtained from adult bone marrow in ability to express phenotypic markers of airway epithelium and to participate in airway remodeling in vivo.
近期研究表明，胚胎干细胞和成体骨髓干细胞均可参与患病成体器官（包括肺）的再生和修复。然而，成体骨髓干细胞介导的气道上皮重塑程度较低，且尚无胚胎干细胞的体内研究数据。人脐带血含有造血干细胞和非造血干细胞，已在临床上用于替代骨髓移植治疗血液系统恶性肿瘤及其他疾病。
我们推测人脐带血干细胞可能是成体骨髓干细胞和胚胎干细胞的有效替代物，可用于损伤气道上皮的再生和修复。
从佛蒙特大学的正常分娩中获取人脐带血。通过流式细胞术和分化试验将培养的贴壁细胞鉴定为间充质干细胞（MSC）。将脐带血来源的间充质干细胞（CB-MSC）在特殊的气道生长培养基中或与特定生长因子（包括角质形成细胞生长因子和视黄酸）一起培养。用PCR和免疫荧光染色分析mRNA和蛋白质表达。将CB-MSC系统性地给予免疫耐受的非肥胖糖尿病/严重联合免疫缺陷（NOD-SCID）小鼠。分析肺中是否存在人类细胞。
当在特殊的气道生长培养基中或与特定生长因子一起培养时，CB-MSC差异表达克拉拉细胞分泌蛋白（CCSP）、囊性纤维化跨膜传导调节因子（CFTR）、表面活性蛋白C和甲状腺转录因子-1 mRNA，以及CCSP和CFTR蛋白。此外，CB-MSC很容易被重组慢病毒载体转导以表达人CFTR。在对免疫耐受的NOD-SCID小鼠进行全身给药后，在气道上皮中发现了罕见的细胞，这些细胞获得了细胞角蛋白和人CFTR表达。
CB-MSC在表达气道上皮表型标志物和参与体内气道重塑的能力方面似乎与从成体骨髓获得的MSC相当。
