Faculty Opinions Recommendation of The Keratins of the Human Beard Hair Medulla: The Riddle in the Middle
TLDR Beard hair medulla cells have a unique and varied keratin pattern.
The study investigated the expression of 52 out of 54 keratins in the human beard hair medulla, revealing that both hair and epithelial keratins were expressed in medulla cells. This included keratins typically found in outer- and inner-root sheaths and the companion layer. A "pre-medulla" was identified, characterized by specific keratins like K5, K14, and K17, which were expressed alongside 12 hair keratins in the medulla proper. The keratin pattern in medulla cells was highly variable, with both epithelial and hair keratins showing promiscuous behavior in heterodimer and intermediate filament (IF) formation. Additionally, cortex cells were found within the medullary column, displaying unique keratin heterogeneity. Medulla cells were distinct in keratin expression and number compared to other hair follicle cells or epithelia.
