Defining Hair Follicles in the Age of Stem Cell Bioengineering

In the 2007 study by Ehama et al., researchers explored the bioengineering of hair follicles by combining human and rodent keratinocytes with dermal papilla (DP) cells and implanting them into mice. The results showed that hair follicles with proper morphology were formed when both cell types were from mice or rats. However, structures created with human keratinocytes and mouse DP cells were incomplete, lacking several key features of normal hair follicles. This study underscored the importance of establishing clear criteria for what constitutes a hair follicle in bioengineering and demonstrated the potential species-specific communication issues when combining human and mouse cells. The paper emphasized the complexity of hair follicle development and the challenges in bioengineering this process.