Investigating Early Molecular Changes in a Model of X-Ray Radiation-Induced Alopecia: Spotlight on Growth Arrest and Endothelial Dysfunction
November 2025
in “
Journal of Investigative Dermatology
”
radiation-induced alopecia x-ray radiation hair follicle Ki-67 matrix keratinocytes outer root sheath CD31 endothelial cells ICAM-1 perifollicular mesenchyme hair growth arrest inflammation vasculature radiation hair loss x-ray hair loss keratinocytes perifollicular area hair growth stop blood vessels
TLDR Radiation-induced hair loss may be caused by hair growth stopping and inflammation in blood vessels.
This study investigates early molecular changes in radiation-induced alopecia (RIA) using ex vivo human hair follicle (HF) irradiation models. After a single 1.8 Gy x-ray dose, significant reductions in proliferating Ki-67+ matrix keratinocytes were observed at 24 hours, and in the outer root sheath at 48 and 72 hours post-treatment. Additionally, there was a significant increase in CD31+ endothelial cells expressing the inflammatory marker ICAM-1 in the perifollicular HF mesenchyme at all time points. Surprisingly, no significant changes were found in cell death, mitotic catastrophe, or DNA damage parameters in various HF compartments. These findings suggest that early RIA changes may be driven by hair growth arrest and inflammation within the HF vasculature.
