Effect of amniotic fluid on hair follicle growth.

Purpose: Human amniotic fluid stem cells (hAFSCs) have shown significant regenerative potential in treating hair loss, wound healing, and tissue repair. This study aims to evaluate the effects of human amniotic fluid (hAF) on hair follicle (HF) regeneration and immune system modulation. Materials and Methods: The hAF used was pooled, acellular, and gamma-irradiated to standardize its contents and enhance its stability. Both irradiated (FAFI) and non-irradiated (FAF) hAF were assessed for their efficacy and safety in promoting hair growth and modulating immune responses in a rat model of hair loss. The study examined HF regeneration, transition to the anagen phase, and macrophage polarization from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype. Results: Both FAF and FAFI treatments significantly increased HF density, with FAFI exhibiting enhanced effects. Histological analysis demonstrated improved HF regeneration, increased M2 macrophages, and reduced collagen fiber deposition in treated areas. Gamma irradiation likely improved the efficacy of FAFI by stabilizing active components and inhibiting protease activity. Conclusions: Irradiated hAF is a safe and effective therapeutic candidate for alopecia and HF growth disorders. These findings support further evaluation of hAF in clinical trials to validate its potential for hair regeneration therapies.