A standardized procedure to obtain mesenchymal stem/stromal cells from minimally manipulated dental pulp and Wharton's jelly samples.

Transplantation of mesenchymal stem/stromalcells (MSCs) has emerged as an effectivemethod to treat diseased or damagedorgans and tissues, and hundreds of clinicaltrials using MSCs are currently under way todemonstrate the validity of such a therapeuticapproach. However, most MSCs used for clinicaltrials are prepared in research laboratorieswith insufficient manufacturing quality control.In particular, laboratories lack standardizedprocedures for in vitro isolation of MSCs fromtissue samples, resulting in heterogeneouspopulations of cells and variable experimentaland clinical results.MSCs are now referred to as Human CellularTissue-based Products or Advanced TherapyMedicinal Products, and guidelines fromthe American Code of Federal Regulation ofthe Food and Drug Administration (21 CFRPart 1271) and from the European MedicinesAgency (European Directive 1394/2007) definerequirements for appropriate production ofthese cells. These guidelines, commonly called"Good Manufacturing Practices" (GMP),include recommendations about laboratorycell culture procedures to ensure optimal reproducibility,efficacy and safety of the finalmedicinal product. In particular, the Food andDrug Administration divides ex vivo culturedcells into "minimally" and "more than minimally"manipulated samples, in function of theuse or not of procedures "that might alter thebiological features of the cells". Today, minimalmanipulation conditions have not beendefined for the collection and isolation ofMSCs (Torre et al. 2015)(Ducret et al. 2015).Most if not all culture protocols that have beenreported so far are unsatisfactory, becauseof the use of xeno- or allogeneic cell culturemedia, enzymatic treatment and long-termcell amplification that are known to alter thequality of MSCs.The aim of this study was to describe a standardizedprocedure for recovering MSCs withminimal handling from two promising sources,the dental pulp (DP) and the Wharton's jelly(WJ) of the umbilical cord. The quality and homogeneityof the expanded cell populationswere assessed by using flow cytometry withcriteria that go beyond the International Societyof Cellular Therapy (ISCT) guidelines forMSC characterization.