Connective Tissue Growth Factor Gene Expression in Tissue Sections From Localized Scleroderma, Keloid, and Other Fibrotic Skin Disorders

Connective tissue growth factor (CTGF) is a novel peptide that exhibits platelet-derived growth factor-like activities and is produced by skin fibroblasts after activation with transforming growth factor-β. Coordinate expression of transforming growth factor-β followed by CTGF during wound repair suggests a cascade process for control of tissue regeneration. We recently reported a significant correlation between CTGF mRNA expression and histologic sclerosis in systemic sclerosis. To confirm the relation between CTGF and skin fibrosis, we investigated CTGF gene expression in tissue sections from patients with localized scleroderma, keloid, and other sclerotic skin disorders using nonradioactive in situ hybridization. In localized scleroderma, the fibroblasts with positive signals for CTGF mRNA were scattered throughout the sclerotic lesions with no preferential distribution around the inflammatory cells or perivascular regions, whereas the adjacent nonaffected dermis was negative for CTGF mRNA. In keloid tissue, the fibroblasts positive for CTGF mRNA were diffusely distributed, especially in the peripheral expanding lesions. In scar tissue, however, the fibroblasts in the fibrotic lesions showed partially positive signals for CTGF mRNA. In eosinophilic fasciitis, nodular fasciitis, and Dupuytren's contracture, CTGF mRNA was also expressed partially in the fibroblasts of the fibrotic lesions. Our findings reinforce a correlation between CTGF gene expression and skin sclerosis and support the hypothesis that transforming growth factor-β plays an important role in the pathogenesis of fibrosis, as it is the only inducer for CTGF identified to date.