Matrix Metalloproteinase-19 Expression in Normal and Diseased Skin: Dysregulation by Epidermal Proliferation

The study examined the expression of Matrix Metalloproteinase-19 (MMP-19) in normal and diseased skin, revealing that MMP-19 was typically found in the basal layer of healthy epidermis but was dysregulated in conditions like psoriasis, eczema, and tinea, extending to suprabasal and spinous layers. The study involved 21 patients and found that MMP-19 expression was upregulated by type I and IV collagens and phorbol myristate acetate, while retinoic acid and dexamethasone downregulated it. These findings suggested that MMP-19 might contribute to the perpetuation of skin diseases by affecting epidermal proliferation and inflammation, potentially aiding pathogen penetration through the epidermal barrier.