Preliminary Histological Evidence of Epidermal and DEJ Remodeling with Microneedling-Assisted Topical Exosome Therapy: A Single-Subject Case Report.

Purpose: This study aimed to evaluate the histological effects of microneedling-assisted topical exosome therapy on the dermoepidermal junction (DEJ) and surrounding epidermal structures in aging skin.

Patients and methods: In this single-subject case report, a healthy 63-year-old male with no known dermatologic or systemic conditions underwent a single session of 0.3 mm microneedling immediately followed by topical application of an exosome-based formulation (E-50 Skin Booster, PrimaCure Co., Ltd., Korea). A 3 mm punch biopsy was collected from the postauricular area at baseline, and a follow-up biopsy was obtained eight weeks post-treatment from an adjacent site. Hematoxylin and eosin (H&E) staining was performed, and histomorphometric parameters were analyzed using high-resolution imaging and AI-assisted quantitative tools.

Results: Histological analysis revealed significant remodeling of the DEJ, with a 17.08% increase in rete ridge count (p = 0.02) and a 7.75% increase in ridge amplitude (p = 0.04). Mean epidermal thickness increased by 52.33% (p = 0.01), and basal keratinocyte density rose by 60.90% (p = 0.01), indicating enhanced regenerative activity. Collagen fiber density in the upper dermis improved by 5.77% (p = 0.05). No adverse effects were reported, and post-treatment tissue showed no signs of inflammation or fibrosis.

Conclusion: Microneedling-assisted topical exosome therapy produced notable structural improvements at the epidermal and dermoepidermal levels in aging skin. Restoration of rete ridges, enhanced keratinocyte proliferation, and increased collagen density suggest a promising role for this combined approach in skin rejuvenation. These findings are specific to microneedling-assisted topical delivery and should not be interpreted as supporting the use of injectable exosomes, which were not evaluated in this study.