Low cutaneous follistatin expression is associated with striae gravidarum: A pilot study of the TGF-β/BMP signaling pathway

Striae gravidarum (SG) causes prominent cosmetic impairment and psychological distress, yet its underlying etiology and molecular mechanisms remain poorly characterized. Unraveling core molecular cascades of SG is critical for developing targeted therapeutics. In this study, we first screened differentially expressed genes among the TGF-β/BMP-related molecules in skin biopsies from four SG patients and six unaffected postpartum controls via TGF-β/BMP-focused PCR Array to prioritize candidate pathogenic genes. F ollistatin ( FST ) emerged as the most prominently downregulated candidate gene in SG, with expression reduced by approximately 225.59-fold in SG lesional skin versus non-SG control skin. We further validated the expression profiles of FST and core related molecules (TGF-β1, BMP4 and Smad3) using molecular assays. Quantitative analyses revealed consistent downregulation of all these molecules in lesional SG skin. Immunohistochemical staining was additionally applied to verify the tissue-level expression pattern of FST. Taken together, our results suggest that low cutaneous FST expression may be associated with the pathogenesis of striae gravidarum.