A Stem Cell Count Would Have Made It Better:
Sartorius: How Can the Evaluation of Tissue Stem Cell Expansion Media Be Enhanced?
Wednesday, December 1, 2021
In this week’s review entry, Asymmetrex takes a look at another important company in human tissue stem cell supply space, but from a different perspective than RoosterBio. Whereas RoosterBio’s primary market focus is supplying expanded human mesenchymal stem cells (hMSCs), Sartorius now markets cell culture medium products for use in the expansion of stem cells, including hMSCs, for both clinical applications and research. Sartorius recently increased its position in this market with its recent acquisition of cell culture media producer Biological Industries, Ltd.
Sartorius is representative of a number of prominent companies that produce and market cell culture medium products for the growth and expansion of therapeutic tissue stem cells, including hMSCs, human pluripotent stem cells (hPSCs), and hematopoietic stem cells (HSCs). Although it is generally well recognized that such products for HSCs provide limited if any HSC expansion capability, the same shortcoming is not the impression for hMSCs media. However, contradicting this prevalent attitude, current functional assays for hMSC-associated activities are well-described for declining after 5-10 passages (PDLs unstated!) in any commercial culture medium.
The difference in attitudes and beliefs about the expansion of HSCs and hMSCs is due to a difference in the expression kinetics of their respective biomarkers by the committed progenitor cells (CPCs) and differentiating cells they produce in culture. In the case of hematopoietic cells, biomarkers like CD34 and CD133, which are expressed by both HSCs and CPCs, decline rapidly in CPCs and their differentiating progeny. However, in contrast, markers like CD73 and CD90, which are also expressed by both MSCs and their progeny CPCs, continue to be expressed in MSC-produced CPCs. So, late passaged cultures of hMSCs can have high fractions of CD73-positive and CD90-positive cells, despite waning levels of MSC function.
Sartorius and its newly acquired hMSC culture medium products are being highlighted in this entry because of its recent e-book announced in the October 22, 2021 issue of RegMedNet’s online Regeneration Weekly newsletter. The e-book introduced Sartorius’s hMSC culture media products and provided attendees with many excellent examples of their effectiveness for culture of mesenchymal tissue cells from several different human tissue sources. It is noteworthy that Sartorius scientists keep their analyses to no more than 5 passages.
Sartorius and other suppliers of cell culture medium products for culturing and maintaining tissue stem cells, like HSCs, hPSCs and hMSCs, would benefit from evaluating the effects of their products on the tissue stem cell-specific fraction during culture. So, would the users of their products as well.
We contacted Maya Rotman, the corresponding author for the application report in Sartorius’s webinar e-book, to get the company’s impressions. Here is their response:
Thank you for focusing on Sartorius’s publication on Reg.Med.Net e-Book, about hMSCs. As you mentioned, Sartorius offers cell culture medium products for maintenance, expansion, and differentiation, as well as cryopreservation, of many types of cells, such as MSCs, iPSCs and immune cells.
Sartorius emphasizes all products go through strict QC tests, and the cells are examined for many characteristics to ensure accurate performance reports. Our R&D and QC labs are up to date with the most advanced performance assays for all our products, and we make a point of delivering reliable and evidence-based results to our customers.
It is reasonable to assume that using advanced mathematical evaluation methods, such as Asymmetrex promotes, for specific counting of therapeutic tissue stem cells could be beneficial for identifying stem cell-specific fractions in later passages, exceeding the first 5-10.
Maya Rotman, MSc
Product Management Organization Support and Content Writer
Next Review: December 15, Tissue Stem Cell-Specific Fraction and Dosage: A Needed Standardization for Stem Cell Medicine