TECHNICAL FOCUS:
Senescence-induced hair follicle aging model for studying hair longevity
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Key takeaway:
Our ex vivo hair follicle aging model can be used to elucidate mechanisms underlying hair follicle aging, testing of senolytics, and protective anti-aging products.
The innovative approach mimics “speed-aging” in hair follicles, specifically targeting DNA damage–related processes and allowing analysis of all key aging markers. This facilitates the development of effective solutions to promote hair longevity.
Intrinsic and extrinsic factors drive cellular senescence — a hallmark of aging. However, the way senescence influences signs of aging in the human hair follicle remains insufficiently understood, representing a critical knowledge gap for the development of cosmetic products that address hair longevity and aging.
To address this data gap, we developed a hair aging model that investigates how DNA damage affects senescence and subsequent human hair follicle function, enabling testing of senolytics and anti-aging products.
Model Induction
BrdU administration in healthy human hair follicle organ cultures significantly increases the number of cells expressing the cell cycle inhibitor p21 in the hair follicle matrix, indicating cell cycle arrest.
Other senescence markers increased by BrdU administration are the DNA damage sensor γH2A.X and cells expressing CXCL10, inducing the release of the senescence-associated secretory phenotype (SASP).
Functional Outcomes
- Reduced hair shaft and keratin production & decreased hair shaft quality
- Reduced hair matrix keratinocyte proliferation
- Increased hair matrix keratinocyte apoptosis
- Promoted catagen development
Thymidine prevents BrdU-mediated hair follicle senescence
Administration of thymidine prevents BrdU-mediated induction of chemokines (MCP-1, IL-8) and proinflammatory cytokines (IL-6, TNF-α), prevents catagen induction, and increases hair shaft production in the senescence-induced hair follicle aging model.


Written by:
Sabrina Hoefling, PhD
Innovation Marketing Project Leader