Topological Laser Delivery Induces Efficient Regeneration Via a Transient Cell Network With Super Activation of Hepatocyte Growth Factor

Fractional CO2 laser treatment has been shown to effectively induce hair regeneration by activating a quorum sensing-like response in mammalian skin, facilitated by macrophage-fibroblast interactions. The study highlights the role of hepatocyte growth factor/scatter factor (HGF/SF) as a key mediator in this process. Macrophages, upon sensing laser-induced injury, secrete HGF/SF to recruit more macrophages and stimulate fibroblasts, creating a self-amplifying regenerative signaling network. This mechanism promotes the transition of hair follicle stem cells from the telogen to anagen phase, resulting in significant hair growth. Clinical studies in patients with androgenic alopecia demonstrated increased hair density from 90 to 135 hairs/cm² after laser treatment, linked to elevated HGF/SF expression. The findings suggest that targeting the HGF/SF-c-Met signaling pathway could enhance regenerative outcomes, offering a promising therapeutic strategy for alopecia.