Heterogeneity of Umbilical Cords as a Source for Mesenchymal Stem Cells

The object of the paper is to show the heterogeneity of 300 cord samples processed in the current research. The differences in effectiveness of mesenchymal stem cell (MSC) isolation are shown. Moreover, the recommendations for choosing the method of MSC isolation depending on the value of stromal-vascular rate are given. The data can be useful for selecting the optimal conditions to obtain MSC and for further cryopreservation of umbilical cord tissue. 1. Introduction Mesenchymal stem cells (MSCs) from umbilical cord matrix are extremely promising for use in regenerative medicine. Accessibility and safety of material selection, absence of ethical conflicts, simplicity of cells isolation, relative homogeneity of the material, and presence of the specific populations of MSCs are the main advantages of umbilical cord matrix as the source of MSCs. Early ontogenetic population of cells can be isolated from properly processed umbilical cord matrix [1–4]. According to a generous amount of modern papers, obtaining MSCs from umbilical cord matrix is considered to be a methodologically easy task [3–6]. Many variations of enzymatic way of umbilical cords’ processing with collagenases of different types, hyaluronidase, trypsin, and other enzymes are proposed by different authors. Moreover the efficiency of mechanical way of processing and various combinations of these approaches are shown [3–9]. The possibility of obtaining the big number of cells from each specimen regardless of any cord characteristic is demonstrated. However, the cord may have individual peculiarities in a case of each organism. MSCs as the part of cord stroma can be more or less available for obtaining depending on organometric characteristics of the cord. Presumably the health of mother and child and the external factors’ influence may have an impact on efficacy of MSC isolation. But that statement needs to be proven. Most of the researches that substantiate the efficiency of different methods of MSC acquiring and claim extremely high amount of obtained cells were made with a low number of samples and thus may not fully reflect the cords’ heterogeneity. After processing 300 samples within 3 years, we have demonstrated that under similar conditions the possibility of cells’ obtaining from different cords is not the same as well as the viability of the resulting cultures. In addition, we have demonstrated that the method for obtaining cells should also be chosen individually based on the organometric characteristics of the cord. We propose to use the stromal-vascular rate (SVR) that can be easily