'Royal College of Obstetricians & Gynaecologists (RCOG)'
Abstract
Extra-embryonic tissues, such as amniotic fluid (AF) and Wharton´s Jelly (WJ) of
umbilical cord, offer many advantages over both embryonic and adult stem cell sources.
These tissues are routinely discarded at parturition and the extracorporeal nature of
these cell sources facilitates isolation, as well as the comparatively large volume and
ease of physical manipulation theoretically increases the number of stem cells that can
be isolated.
Autologous approaches to use MSCs, namely from bone marrow, have difficulties
regarding the limited availability of large amounts of cells from the patient. Fetal stem
cells appear to have even more pronounced immunomodulatory properties than adult
MSCs (1, 2). This allogeneic escape mechanism may be of therapeutic value, because
transplantation of allogeneic human MSCs in stock would be readily available, as
opposed to the culture of autologous cells for subsequent transplantation.
Cell expansion protocols are based on the use of media supplemented with fetal bovine
serum (FBS) as a source of nutrientes and growth factors. The animal serum is not
completely safe, once there is a possibility of contamination by animal viroses, prions or
others contaminants and it is described that FBS used systematically in MSCs
subcultivation induces more humoral immune response (3). Additionally anti-FBS
antibodies could be detected in patients after receiving MSCs expanded in FBS (4).
Platelet lysate (PL) has enormous possibilities in cell therapy, namely because of the
high concentration of growth factors that promotes higher cell expansion, such as tissue
regeneration (5). A recent study showed that proliferation of MSCs was much higher on
PL gel compared to tissue culture plastic (6). The immunomodulatory properties of
MSCs are maintained when expanded in culture medium supplemented with PL (7)
Based on these premises we isolated fetal stem cells from AF obtained from
amniocentesis and WJ from umbilical cords. These cells were plated and expanded in low density numbers in basal culture medium with FBS or either supplemented with PL.
In each passage cells were counted for proliferation kinetics and prepared for flow
cytometry analysis. Expanded populations were analysed both population size and
complexity and for the MSCs well-known surface markers (CD34, CD45, CD73, CD44,
CD106, CD105, CD29, CD90, CD31) and markers related with immune response (HLADR,
80, 83, 86) and embryonic markers SSEA-4 and TRA-1-60
