A comparative analysis of ASC expansion in hollow fiber bioreactors and tissue culture polystyrene flasks: impact on immunophenotypes

Adipose-derived stem cells (ASCs) hold significant promise for various regenerative applications. However, a large number of in vitro expanded ASCs is required for practical therapies. The immunophenotypical profiles, influenced by cell population times, play a pivotal role in shaping ASC potency. In the context, ASC cultures from the hollow fiber bioreactor (HFB) were compared with the traditional tissue culture polystyrene (TCP) flasks, with an emphasis on the immunophenotypes. The ASCs for three donors were expanded in the two systems for an equivalent number of population doublings and analyzed for the co-expression of 13 epitopes included Panel A (CD73, CD90, CD105, CD166, and CD201) and Panel B (CD34, CD36, D146, CD200, CD248, CD271, CD274, and Stro-1) by multichromatic flow cytometry. The HFB supported faster growth rates, with an average doubling time (DT=1.24) being shorter than that in the TCP system (DT=1.52). Regarding the lineage prevalence, the CD201+ clones were favored in the TCP conditions, whereas those lacking the CD274 had predilection for the HFB environment. Furthermore, the HFB paradigm promoted more immunophenotypical heterogeneity and greater donor-to-donor variation. Samples from one of the donors appeared highly discrepant from the rest, mitigating thus differences between the systems. HFB appears to provide for an accelerated expansion and less immunophenotypical selection pressure than the TCP with the caveat that some rare donors may yield unique lineages that can be propagated only in a specific system. Our study provides a useful basis for rational decision making regarding the choice of in vitro ASC expansion approaches.