Mesenchymal stem cells derived from Wharton's jelly: comparative phenotype analysis between tissue and in vitro expansion.

Mesenchymal stem cells (MSCs) are useful multipotent stem cells that are found in many tissues. While MSCs can usually be isolated from adults via bone marrow aspiration (BM-MSCs), MSCs derived from the discarded umbilical cord, more precisely from Wharton's jelly (WJ), offer a low-cost and pain-free collection method of MSCs that may be cryogenically stored, and are considered extremely favorable for tissue engineering purpose. The aim of this study was to analyze the harvested number of cells per centimeter of human umbilical cord (UC) and carry out the phenotype of these WJ-MSCs after explant or enzymatic methods. Fresh UCs were obtained from full-term births, and processed within 6 hours from partum to obtain the WJ-MSCs. UC sections were analyzed in confocal microscopy to analyze cells phenotype in situ. Others UC components were treated either by enzymatic method or by explant method to obtain isolated cells and to analyze cells phenotype until the end of the first passage. We have successfully generated MSCs from UC by using explant and enzymatic methods. Using microscopy confocal, we identified the expression of some MSCs markers in situ of Wharton's jelly tissue as well as in perivascular region. Our comparative study, between explant and enzymatic digestion, indicated, that WJ expressed most of MSCs markers in both conditions, but a remarkable variation of cell phenotype expression was distinguished after primary culture comparing to directly isolated cells by enzymatic digestion. We also studied the expression of CD271, which showed to be weakly expressed in situ on fresh fragment of WJ.