Human Mesenchymal Stromal Cell (MSC) Characteristics Vary Among Laboratories When Manufactured From the Same Source Material: A Report by the Cellular Therapy Team of the Biomedical Excellence for Safer Transfusion (BEST) Collaborative

Abstract

Background: Culture-derived mesenchymal stromal cells (MSCs) exhibit variable characteristics when manufactured using different methods and different source materials. The purpose of this study was to assess the impact on MSC characteristics when different laboratories propagated MSCs from cultures initiated with BM aliquots derived from the same donor source material. Methods and Methods: Five aliquots from each of three different BM donors were distributed to five independent laboratories. Three laboratories plated whole BM and two laboratories a mononuclear BM cell fraction. Four laboratories cultured in media supplemented with fetal bovine serum (FBS) and one laboratory used human platelet lysate (hPL). Initial cell seeding densities (i.e., P0) ranged from 19.7 × 10 3 /cm 2-282 × 10 3 /cm 2 and for second seeding (i.e., P1) 0.05 × 10 3-5.1 × 10 3 cells/cm 2. Postthawed MSCs from each laboratory were analyzed for cell viability, immunophenotype, tri-lineage differentiation, fibroblast colony-forming units (CFU-F), gene expression, and immunosuppressive activity. Results: Transit times from BM collection to receipt by laboratories located in the United States ranged from 16.0-30.0 h and from 41.5-71.5 h for a laboratory in Asia. Post-thaw culture derived MSCs rom BM #1, #2, and #3 exhibited viabilities that ranged from 74-92%, 61-96%, and 23-90%, respectively. CFU activity from BM #1, #2, and

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“…A striking example illustrating the influence of different isolation, culture, and cryopreservation methods was demonstrated by Stroncek et al in an experiment in which MSCs were manufactured from the same source material [ 33 ]. The authors pointed out that “manufacturing of MSCs by five independent centers contributed more to MSC variability than did the source material of the bone marrow” used in the study.…”

More Human BM-MSC With Similar Subpopulation Composition and Functional Characteristics Can Be Produced With a GMP-Compatible Fabric Filter System Compared to Density Gradient Technique

“…The presented characterization concept could have missed relevant, currently unknown, distinctive functional MSC features. To conclusively assess possible therapeutic differences, in vivo studies in adequate preclinical models are suggested, ideally in a multicenter study setting, as a recent study showed that the local manufacture process highly affects functional and molecular differences between MSC preparations ( Stroncek et al, 2020 ).…”

Mesenchymal Stem Cells as a Cornerstone in a Galaxy of Intercellular Signals: Basis for a New Era of Medicine

“…Recently, Stroncek et al described functional and molecular differences between the MSC of three patients produced in five different laboratories, despite the fact that the origin of these cells was the same [ 327 ]. These situations occur because, today, there is no standardized protocol for each one of four key steps of the MSC manufacturing process: donor MSC selection and collection, maintenance and transport of the MSC from the collection site to the processing site, culture strategy (i.e., plating cells, passaging the adherent cells, and harvesting the MSC), and cryopreservation and storage of the manufactured MSC.…”