A Novel Method of Isolation of Mesenchymal Stem Cells from Human Umbilical Cord Tisssues.

Mesenchymal stem cells (MSCs) have been isolated from venous endothelia and subendothelia of the human umbilical cord using a tedious procedure. We established a simple method to isolate abundant MSCs from human umbilical cord tissues (UC). 36 full-term umbilical cords were obtained. MSCs were isolated after enzyme digestion of minced cord fragments. The mean nucleated cells isolated from UC was 1.13±0.37×106/cm UC. A total of 1×10e10 MSCs was obtained after several passages over 4 weeks. CFU-F frequency is 1:1609. The population doubling time was approximately 28.02±10.53 h in passage 2 cells. The MSC cells were positive for CD13, CD29, CD44, SH-2, SH-3, CD166 and HLA class I (A, B, C), but were negative for CD34, CD38, CD45, CD31 and HLA-DR. More than 80% cells were in G0-G1 phase, whereas a small population of cells was engaged in proliferation (S+G2+M=9.16%). Under specified culture conditions, the MSC cells differentiated into adipocytes, osteoblasts and neural cells. The MSCs were also found to express cytokines of SCF, LIF, M-CSF, Flt3-ligand, IL-6, GM-CSF, G-CSF, VEGF, and SDF-1. When co-cultured with CD34+ cells from UC blood, the UC-derived MSCs were able to support the hematopoiesis of long-term culture-initiating cells. These findings suggested that abundant MSCs can be isolated simply and effectively from the whole cord tissue. Umbilical cords may be an attractive source of MSCs for tissue engineering, cord blood expansion and cord blood transplantation.