Back to the Future: From Appendage Development Toward Future Human Hair Follicle Neogenesis.

Area of Science:

• Developmental biology
• Regenerative medicine
• Dermatology

Background:

• Hair disorders like alopecia impact well-being, and hair follicle (HF) research is vital for wound healing and scar prevention.
• Human HF development remains incompletely understood, with studies often relying on animal models that show significant species differences.
• Developing human-specific models is essential for advancing therapies for hair loss and skin regeneration.

Purpose of the Study:

• To review current knowledge on cellular changes during human skin and hair follicle development.
• To explore the potential of using this knowledge to create human in vitro skin models with hair follicles.
• To discuss the clinical translation of these advanced skin models.

Main Methods:

• Review of existing literature on human fetal skin and hair follicle development.
• Analysis of cellular and extracellular matrix (ECM) protein roles in hair genesis.
• Discussion of organoid and skin-on-chip technologies for in vitro modeling.

Main Results:

• Hair follicle progenitor cells in human fetal skin form hair buds and subsequently HFs through specific developmental processes.
• Understanding hair genesis is key to recapitulating complex 3D skin structures like hair organoids.
• Knowledge of fetal skin cellular and ECM components is critical for understanding epithelial tissue evolution.

Conclusions:

• Elucidating human hair follicle development is indispensable for creating advanced in vitro skin models.
• Patient-derived hair organoids and skin-on-chip models hold promise for personalized therapy and research.
• Translating in vitro models to clinical applications could revolutionize treatments for hair disorders and severe burns.