Enhanced Expansion and Sustained Inductive Function of Skin-Derived Precursor Cells in Computer-Controlled Stirred Suspension Bioreactors

Abstract

Endogenous dermal stem cells (DSCs) reside in the adult hair follicle mesenchyme and can be isolated and grown in vitro as self‐renewing colonies called skin‐derived precursors (SKPs). Following transplantation into skin, SKPs can generate new dermis and reconstitute the dermal papilla and connective tissue sheath, suggesting they could have important therapeutic value for the treatment of skin disease (alopecia) or injury. Controlled cell culture processes must be developed to efficiently and safely generate sufficient stem cell numbers for clinical use. Compared with static culture, stirred‐suspension bioreactors generated fivefold greater expansion of viable SKPs. SKPs from each condition were able to repopulate the dermal stem cell niche within established hair follicles. Both conditions were also capable of inducing de novo hair follicle formation and exhibited bipotency, reconstituting the dermal papilla and connective tissue sheath, although the efficiency was significantly reduced in bioreactor‐expanded SKPs compared with static conditions. We conclude that automated bioreactor processing could be used to efficiently generate large numbers of autologous DSCs while maintaining their inherent regenerative function. Stem Cells Translational Medicine 2017;6:434–443

Therapeutic Potential of Stem Cells in Follicle Regeneration

“…Apart from cells of the “bulge,” stem cells reside specifically in the HF mesenchyme and function to replenish the dermal papilla and connective tissue sheath. They are called self-renewing dermal stem cells (DSCs) [ 56 , 57 ]. When transplanted, DSCs integrate with mesenchymal cells and they act together with epithelial stem cells, participating in creating new hair follicles [ 56 , 57 ].…”

“…They are called self-renewing dermal stem cells (DSCs) [ 56 , 57 ]. When transplanted, DSCs integrate with mesenchymal cells and they act together with epithelial stem cells, participating in creating new hair follicles [ 56 , 57 ]. In cultures, they form spherical, self-regenerating colonies.…”

“…Therefore, methods have been developed for their simultaneous collection, isolation, and administration in vivo at acceptor sites with the use of the so-called stirred suspension bioreactors. They help to obtain cells of greater uniformity; increased cell density per volume; and control of the concentration of nutrients, metabolites, and growth factors [ 56 , 58 ].…”

Hair follicle dermal stem cells and skin‐derived precursor cells: Exciting tools for endogenous and exogenous therapies

“…Although studies have suggested that Sox2 is necessary for hair follicle induction, a more recent conditional knockout study has shown that Sox2 is not essential for HF morphogenesis . When adult Sox2 + hfDSCs are isolated and grown in vitro, we observe a rapid loss of Sox2 expression over time, yet retain at least partial inductive function which is sustained for several passages. Is Sox2 an intrinsic property of hfDSCs or is it environmentally regulated?…”

Multipotentiality of skin‐derived precursors: application to the regeneration of skin and other tissues

“…However, a new way to expand SKP was highlighted in a recent scientific publication. Indeed, the expansion of SKPs can be enhanced using computer‐controlled stirred suspension bioreactors . This technique allows a large number of SKPs (five‐fold greater than static culture) to be cultivated from the same donor for clinical use.…”