Evaluation of animal models for the hair-inducing capacity of cultured human dermal papilla cells.

Background: The dermal papilla (DP) interacts with epithelial cells for folliculogenesis. For translational research on cell therapies for hair regrowth with cultured human DP cells (hDPCs), a model to evaluate the capacity of hDPCs to induce hair formation is inevitable.

Methods: Chamber models were constructed by transplanting 4 different combinations of mouse or human epithelial and mesenchymal cells into a silicone chamber implanted onto the back of nude mice. In parallel, 3 types of sandwich constructs were created by inserting hDPCs or human DP tissue between the epidermis and dermis of isolated rat footpad skin or human facial skin, and subcutaneously transplanting the constructs into the back of nude mice. Four to six weeks later, skin sections of each model were histologically examined.

Results: Folliculoneogenesis was detected in both chamber and sandwich models, although the induction rate and maturity of the hair follicles varied among cell combination subgroups in each model. The difference in hair induction rate was not statistically significant between 2 representative chamber and sandwich subgroups using cultured hDPCs. The sandwich model, however, required fewer hDPCs, did not require human keratinocytes, and exhibited a higher rate of successful sample collection.

Conclusions: Although there is no significant difference in hair induction rate, the sandwich model using cultured hDPCs and the rat sole skin is more feasible than the chamber model using human cultured keratinocytes and hDPCs as a tool to evaluate the hair-inducing capacity of cultured hDPCs.