TLDR Certain immune cells in the skin release a protein that stops hair growth by keeping hair stem cells inactive.
In 2019, researchers discovered that a subset of TREM2+ dermal macrophages, also known as trichophages, secrete Oncostatin M (OSM), a cytokine that inhibits hair growth by keeping hair follicle stem cells (HFSCs) in a resting state. This is achieved through the OSM-OSMRβ-STAT5 signaling pathway. When these macrophages were removed, hair growth and HFSC activation occurred. Genetic deletion of the OSM receptor or STAT5 also led to premature HFSC activation, indicating that the resting stage of hair growth is actively maintained by the hair follicle niche. The study suggests that manipulating this pathway could potentially regulate hair growth.
202 citations,
August 2017 in “Nature cell biology” Lactate production is important for activating hair growth stem cells.
159 citations,
October 2015 in “Science Advances” Blocking JAK-STAT signaling can lead to hair growth.
173 citations,
August 2015 in “Developmental cell” The study identified unique genes in hair follicle cells and their environment, suggesting these genes help organize cells for hair growth.
40 citations,
April 2014 in “Genes & Development” Hormones during pregnancy and lactation keep skin stem cells inactive, preventing hair growth.
144 citations,
September 2012 in “Genes & development” Aging causes skin stem cells to work less effectively.
91 citations,
May 2003 in “American Journal of Pathology” Prolactin affects hair growth cycles and can cause early hair follicle regression.
73 citations,
November 2000 in “Proceedings of the National Academy of Sciences of the United States of America” There are two ways to start hair growth: one needs Stat3 and the other does not, but both need PI3K activation.
27 citations,
January 2020 in “Experimental Dermatology” Immune cells affect hair growth and could lead to new hair loss treatments.
4 citations,
April 2019 in “Cell Stem Cell” Certain immune cells in the skin can stop hair from growing.
June 2023 in “Stem cell reviews and reports” Stem cell therapies could be a promising alternative for hair loss treatment, but more research is needed to understand their full potential and safety.
59 citations,
March 2020 in “Journal of Biomedical Science” Understanding how hair follicle stem cells work can help find new ways to prevent hair loss and promote hair growth.
April 2024 in “Frontiers in physiology” Immune cells are crucial for hair growth and preventing hair loss.
