Stem Cell Therapy – When We Can Use Such Terminology?

This article refers to:

The Effect of Adipose-Derived Stromal Vascular Fraction Cells to Abdominal Wall Fascia Defects in Rats: An Experimental Study

Regenerative medicine utilizing tissue engineering techniques is gaining more and more attention among many clinical specialities [1]. Actually the most popular therapy is use of mesenchymal stromal cells isolated from bone marrow (BM-MSCs) or adipose tissue (AD-MSCs). In many articles abbreviation MSCs is expanded as mesenchymal stem cells, however according to the International Society for Cellular Therapy (ISCT), the correct expansion should be stromal instead of stem cells [2]. Among these two cell sources, adipose tissue is more often used, due to the low-invasive method of tissue collection (liposuction), and richer content of mesenchymal stromal cells [3]. In clinical practice, there are two approaches of cellular therapy: utilization of homogenous cultured MSCs or use of freshly isolated uncultured Stromal Vascular Fraction (SVF, in case of fat tissue) or Bone Marrow Mononuclear Cells (BMMCs). Both therapies are often described as the stem cell therapy, however in case of SVF and BMMC such wording is misleading. The amount of MSC in SVF is approximately 1%, and in the case of BMMC about 0.001–0.002% [3]. The advantage of using SVF and BMMC are: low-cost procedure of cell isolation and quick preparation time. Both cell types can be applied during one surgical procedure, from tissue collection to cell transplantation [4]. Additionally on the market there are automated closed devices available, that allow for isolation of these cell types, and what is also very important, the use of these devices do not require additional staff, simple training in the equipment operation is enough. That is why this method is more often used by clinicians, especially in plastic surgery, but also in other clinical specialities including surgery [5,6]. Utilization of cultured MSCs is more difficult. First of all, this method is time-consuming, in order to obtain appropriate number of cells for transplantation, about 2–3 week of cell culture is needed. This is associated with the patient awaiting for the final product, and with two visits in the operating room. Second point is cost, each cells, which are expanded in laboratory, in order to be used in clinical practice have to be processed in clean rooms according to Good Manufacture Practice (GMP) guidelines. This generate high costs, which are associated with laboratory maintenance, appropriate reagents, tests necessary for release of the final product, and moreover specially qualified laboratory staff is required. The other issue is a danger of not obtaining necessary cell number, which is associated with cell senescence. Cells should be passaged maximally to 6th passage in order to maintain their regenerative properties, in some cases that time point may be not enough to obtain appropriate cell number, especially if the tissue source for cell isolation is limited [7,8]. In exchange for such restricted procedure we receive product which consists almost entirely of MSCs (>95%). Advantage of use cultured MSCs is also fact, that patient will obtain fully phenotypically characterized cell product. According to ISCT MSC must express CD105, CD73 and CD90 with lack of expression of CD45, CD34, CD14 or CD11b, CD79alpha or CD19 and HLA-DR surface molecules [2]. In SVF and BMMCs, beside MSCs, other cells like endothelial, pericitic and hematopoietic cells are present, which also through paracrine effect can influence the regeneration process [9,10]. However compared to heterogeneous population of SVF and BMMCs, pure MSCs have greater regenerative potential. Beside paracrine effect they can differentiate into many cell types, osteogenic, adipogenic and chondrogenic potential of MSC is also one of minimal criteria defining MSCs [7]. Like mentioned above, both methods have pros and cons, however in order to use “real” stem cell therapies more often in clinical practice, additional improvements in cell preparation, reducing the cost of procedure, have to be performed.

Disclosure statement

No potential conflict of interest was reported by the author(s).