Role of matrix metalloproteinases 1, 2, and 9 and tissue inhibitor of matrix metalloproteinase-1 in chronic venous insufficiency

Purpose: Increased transforming growth factor-beta (1) (TGF-beta (1)) activ ity is associated with chronic venous insufficiency (CVI) disease progressi on and dermal skin pathology. Because TGF-beta (1) stimulates collagen synt hesis and alters the levels of matrix metalloproteinases (MMPs) and their i nhibitors (TMPs), we investigated the hypothesis that increased TGF-beta (1 ) activity is associated with differences in messenger RNA and protein leve ls of MMPs and TIMP-1 in patients with CVI. Methods: One hundred ten biopsies of the lower calf and lower thigh in 73 p atients were snap frozen in liquid nitrogen and stratified into six groups according to the clinical etiologic anatomic distribution pathophysiology d isease classification. One set of lower-calf and lower-thigh biopsies were analyzed for MMP-1 and TIMP-1 gene expression with quantitative reverse tra nscription and competitive polymerase chain reaction. A second set of biops ies was analyzed for the active and latent forms of MMP-1, MMP-2, and MMP-9 as well as for TMP-1 by western blotting, gelatin zymography, and tissue l ocalization by immunohistochemistry (IHC). Results: Compared with the control, MMP-1 messenger RNA was increased in cl ass-4 and class-6 patients (P less than or equal to .01), whereas TIMP-1 wa s increased in class-6 patients only (P less than or equal to .05). However , there were no differences in total protein between MMP-1 and TIMP-1. Acti ve MMP-2 protein increased in class-4 and class-5 patients compared with ac tive MMP-1 and TIMP-1 (P less than or equal to .01). Western blotting did n ot identify the active component of MMP-9. Similarly, only the latent form of MMP-9 was observed by gelatin zymography, whereas both the latent and ac tive forms of MMP-2 were observed. IHC demonstrated AM-1 and MMP-2 in derma l fibroblasts and in perivascular leukocytes. TIMP-1 was observed in basal- laver keratinocytes of the epidermis only. MMP-9 was not detected by IHC. Conclusion: MMP synthesis is regulated at both the transcriptional and post - transcriptional levels in CVI. Our data suggest that post- translational modifications are key to functional regulation. Dermal fibroblasts and migr ating leukocytes are probable cellular sources of MMPs. Increased active MM P-2 levels in class-4 and class-5 patients indicate tissue remodeling cause d by pre-ulcer and postuleer environmental stimuli. These data suggest that alterations in MMP-2 activity, in conjunction with TGF-beta (1)-mediated e vents, cause an imbalance in tissue remodeling leading to a pro-ulcer-formi ng environment.