Distinct diversity of skin cell populations of rhinophyma and hypertrophic scar illustrated by scRNA-seq.

INTRODUCTION: The clinical manifestations and presentation of rhinophyma closely resemble those of hypertrophic scar tissue, both presenting as firm, fibrotic growths. Despite this phenotypic similarity, a critical divergence is observed following surgical intervention: the affected skin in rhinophyma can revert to its normal state without scar recurrence, a favorable outcome starkly contrasting with the behavior of hypertrophic scars. The underlying mechanisms for this phenomenon have yet to be elucidated. The aim of this study is to uncover the cellular and molecular disparities between these two pathological conditions using single-cell sequencing technology to resolve this clinical paradox. The objective of this study is to compare the single-cell transcriptomic profiles of rhinophyma and hypertrophic scar tissues to identify key cell types and molecular pathways that may account for the distinct healing fate of rhinophyma post-surgery and provide novel insights for the prevention and treatment of hypertrophic scars. METHODS AND RESULTS: We isolated single cells from rhinophyma and hypertrophic scar tissues and conducted transcriptomic analysis using high-throughput single-cell RNA sequencing technology. Employing bioinformatics methods, we analyzed the data to identify differentially expressed genes and cellular subpopulations. Our results indicate that epithelial cells in hypertrophic scar tissues exhibit distinct fibrotic characteristics not observed in rhinophyma tissues. Vascular structures in hypertrophic scar tissues are enveloped by a significant number of stromal cells, in contrast to the leaky vascular profiles observed in rhinophyma tissues. Furthermore, keratinocytes in hypertrophic scars display disordered proliferation, while the number of immune cells in rhinophyma is significantly higher than in hypertrophic scar tissues. CONCLUSION: These findings reveal fundamental differences in cellular composition and functionality between rhinophyma and hypertrophic scar tissues, the intrinsic differences in the tissue microenvironment predispose them to divergent healing trajectories following the same insult, offering new perspectives on the healing process of rhinophyma post-surgery and potentially providing molecular targets for the development of scar prevention strategies.