Expression of vascular endothelial factor-A, gelatinases (MMP-2, MMP-9) and TIMP-1 in uterine leiomyomas

Background: Leiomyomas growth involves cellular hypertrophy, modulation of mitotic activity and upregulation of extracellular matrix (ECM). Vascular factors and matrix metalloproteinases (MMPs) play a coordinated role during neoplasia and tissue remodeling. The present study investigates the role of angiogenic factor vascular endothelial growth factor (VEGF)-A with the activity of main gelatinases, MMP-2/MMP-9 and their tissue inhibitor TIMP-1 in patients with leiomyomas. Methods: Peripheral blood of 46 women with uterine leiomyomas was obtained prior hysterectomy to assess VEGF-A, MMP-2, -9, TIMP-1 levels by enzyme-linked immunosorbent assay compared to 39 healthy controls. Protein expression levels of VEGF-A, MMP-2 and MMP-9 were evaluated by western immunoblotting and immunohistochemistry in leiomyomas tissue specimens after hysterectomy. Furthermore, the activity of gelatinases in leiomyoma tissue extracts and control myometrium was evaluated by semi-quantitative zymography. Results: Circulating levels of VEGF-A, MMP-2 and TIMP-1 were significantly elevated in leiomyoma patients compared to controls (p<0.001, p=0.004, p=0.003, respectively). A positive correlation was found between VEGF-A and MMP-2 (p=0.021) as well as MMP-9 (p=0.001) peripheral levels in the patient's group. Furthermore, increased VEGF-A protein levels were detected in leiomyoma tissue compared to control myometrium, followed by increased localization of both VEGF-A and MMP-2 in the ECM embedding bundles of smooth muscle cells of leiomyomas. The activity of MMP-2 was significantly higher in leiomyomas than normal myometrium in all investigated tissues. Conclusions: This study demonstrates a possible coordinated role of VEGF-A and MMP-2 during uterine leiomyomas growth and angiogenesis with potential prognostic significance.