Jino Kim

Androgenetic alopecia (AGA) is a common form of hair loss characterized by androgen-driven tissue remodeling, including progressive follicular miniaturization and dermal fibrosis, which is accompanied by low-grade immune activation. However, the molecular mechanisms underlying this fibroimmune dysfunction remain poorly understood. Dermal fibroblasts (DFs) have been suggested as androgen-responsive stromal cells and a potential source of CXCL12, a chemokine implicated in fibroimmune pathology, but their precise role in AGA has not been fully established. In this study, we performed single-cell transcriptomic profiling of a testosterone-induced mouse model of AGA, with or without treatment of CXCL12-neutralizing antibody, to elucidate the pathological role of CXCL12 in mediating stromal-immune interactions. Our analysis suggested that DFs are the primary androgen-responsive population driving CXCL12 expression. Autocrine CXCL12-ACKR3 signaling in DFs activated TGF-β pathways and promoted fibrotic extracellular matrix deposition. In parallel, paracrine CXCL12-CXCR4 signaling reprogrammed Sox2⁺Twist1⁺ dermal papilla cells (DPCs) and promoted the accumulation of pro-fibrotic Trem2⁺ macrophages, contributing to impaired hair follicle regeneration. Notably, CXCL12 blockade attenuated these stromal and immune alterations, restored the regenerative capacity of DPCs, reduced pro-fibrotic macrophage infiltration, and promoted hair regrowth. Together, these findings identify CXCL12 as a central mediator of androgen-induced fibroimmune remodeling and highlight its potential as a therapeutic target in AGA.

Introduction: Achieving a natural, aesthetically pleasing hairline is a key objective in hair transplant surgery. However, many patients erroneously assume that perfect symmetry between the left and right sides of the hairline is crucial for natural results. This misconception neglects the natural asymmetry in facial structures, including hairlines. This study quantifies the degree of asymmetry in hairline direction among male subjects, providing evidence to guide hairline design for optimal outcomes. Materials and Methods: The study included 125 East Asian males with Norwood-Hamilton stage II or lower, none of whom had undergone hair restoration surgery. Standardized 60-degree photographs were used to minimize distortion, and hair growth angles were measured using Microsoft Snip & Sketch’s protractor tool. Measurements were taken at specific points along the hairline, and paired t tests were performed to assess asymmetry. Results: Significant rightward asymmetry in hairline direction was found, averaging 22.2 degrees. The mean hair angle on the right side was 55.03 degrees, whereas the left averaged 32.83 degrees ( P < 0.001). Only 8.8% of subjects exhibited greater leftward asymmetry. Conclusion: This study highlights the prevalence of natural asymmetry in male hairlines, particularly a rightward skew. Symmetrical hairline designs may appear unnatural, whereas embracing this asymmetry can lead to more harmonious results. Educating patients about these findings can enhance satisfaction. Further research should explore the impact of sex, ethnicity, and skull morphology on hairline asymmetry.

We previously demonstrated that C-X-C Motif Chemokine Ligand 12 (CXCL12) is primarily secreted by dermal fibroblasts in response to androgens and induces hair miniaturization in the mouse androgenic alopecia (AGA) model. However, the direct effects of androgen-induced CXCL12 on dermal papilla cells (DPCs) and dermal sheath cup cells (DSCs) have not been demonstrated. First, we compared single-cell RNA sequencing data between mouse and human skin, and the results show that CXCL12 is highly co-expressed with the androgen receptor (AR) in the DPCs and DSCs of only human hair. Immunohistochemistry also showed that CXCL12 is co-expressed with the AR in the DPCs and DSCs of human hair follicles. In human hair organ culture, androgens also increased CXCL12 expression in DPCs and DSCs and reduced hair length, while the CXCL12 antibody increased hair length via AR inactivation. CXCL12 mRNA was upregulated by androgen treatment in primary human DPCs and DSCs. On the contrary, AR inhibitors or siRNA treatment reduced CXCL12 expression. Collectively, these results suggest that CXCL12 is co-expressed with the AR in the DPCs and DSCs of human hair follicles; therefore, inhibition of CXCL12 using antibodies is a promising strategy for AGA treatment.

Background: Achieving successful outcomes in hair transplant surgery involves various critical factors, including donor area harvesting, graft survival, and minimizing post‐operative complications. This study investigates the differences in grafts obtained using the rotary and oscillatory punch methods during follicular unit extraction (FUE) surgery.Methods: The study involved 15 patients undergoing FUE. Four 4 × 6 cm² areas in two rows were selected for each patient, with each row utilizing a different punch method (rotary or oscillatory). The grafts were extracted and examined under a microscope, classified into single, double single, double, and triple categories. The total yield rate and average number of hairs per graft were measured and compared.Results: The average number of hair follicles per graft was 2.029 for the rotary method and 2.084 for the oscillatory method, indicating no statistically significant difference. However, the total yield rate was 88.3% for the rotary group and 90.5% for the oscillatory group, with the difference being statistically significant. In selected cases with soft scalps or deeper punch requirements, the oscillatory method showed significantly better results, with an average of 2.078 hairs per graft compared to 1.836 for the rotary method. The total yield rate in these cases was 91% for oscillatory and 86% for rotary.Conclusion: While the overall differences between rotary and oscillatory punches are minimal, the oscillatory punch is significantly more effective in cases with soft scalps or deeper punch requirements. Adhering to a structured guideline before extraction can help reduce the transection rate and increase the number of hairs per graft.