Engineered Exosomes Co-Delivering EGF and FGF Ameliorate Androgenetic Alopecia in a Mouse Model.

BACKGROUND: Androgenetic alopecia (AGA) is characterized by hair follicle miniaturization and growth factor deficiency. However, conventional therapies such as minoxidil and finasteride fail to restore the pathological follicular microenvironment, highlighting the urgent need for novel therapeutic strategies. Epidermal growth factor (EGF) and fibroblast growth factor (FGF) are key regulators of hair follicle regeneration, yet their expression is downregulated in the follicular microenvironment of AGA patients. METHODS: This study validated the expression profile of growth factors in hair follicles of AGA patients through clinical sample analysis. Subsequently, dual‑factor engineered exosomes (EXO‑EGF/FGF) loaded with EGF and FGF were constructed using LAMP2B fusion engineering technology with 293T cells as donor cells. EXO‑EGF/FGF was characterized by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). The regulatory effects of EXO‑EGF/FGF on human dermal papilla cells (HDPCs) were evaluated in vitro. An androgen‑induced AGA mouse model was established to assess the therapeutic efficacy and safety of EXO‑EGF/FGF in vivo. RESULTS: Clinical sample analysis confirmed that the expression of EGF and FGF was significantly downregulated in dermal papilla cells of AGA patients, leading to reduced expression of NOTCH signaling pathway proteins associated with hair follicle regeneration. TEM and NTA results demonstrated that EXO‑EGF/FGF exhibited exosomal morphology, with significantly higher expression levels of EGF and FGF than natural exosomes. In vitro experiments revealed that EXO‑EGF/FGF promoted the proliferation and migration of HDPCs by reactivating the cell cycle and enhancing migration‑related programs. In the AGA mouse model, EXO‑EGF/FGF effectively restored hair coverage density and follicular structural integrity without inducing immunogenic reactions or systemic toxicity, and significantly increased the number of anagen‑phase hair follicles in post‑treatment tissues. CONCLUSION: This study demonstrated that LAMP2B‑engineered EXO‑EGF/FGF acted on follicular cells to repair the pathological microenvironment in AGA. This strategy overcame the inherent limitations of conventional therapies and natural exosomes, offering a novel, safe, and clinically translatable therapeutic approach for AGA treatment.