Levels of Matrix Metalloproteinase-9 and Tissue Inhibitor of Metalloproteinase-1 mRNAs in Patients with Primary Hypertension or Hypertension-induced Atherosclerosis

OBJECTIVE: Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) affect degradation of vascular elastin, collagen remodelling and formation of atherosclerotic plaque. This cross-sectional study investigated the levels of MMP-9 and TIMP-1 mRNAs in the blood of patients with primary hypertension with and without hypertension-induced carotid atherosclerosis. METHODS: Hypertensive patients with and without atherosclerosis and age- and gender-matched normotensive subjects were enrolled. MMP-9 and TIMP-1 mRNA were quantified using real-time reverse transcription-polymerase chain reaction. RESULTS: Hypertensive patients (n = 86) had significantly lower levels of TIMP-1 mRNA than normotensive subjects (n = 43). Hypertensive patients with atherosclerosis (n = 42) showed significantly elevated levels of MMP-9 mRNA compared with both normotensive subjects and hypertensive patients without atherosclerosis (n = 44). CONCLUSIONS: Primary hypertension resulted in decreased TIMP-1 mRNA levels, suggesting a potential mechanism contributing to the degradation of elastin. Hypertension-induced atherosclerosis was associated with significantly increased levels of MMP-9 mRNA, which may enhance both the deposition of types I and III collagen and atherosclerotic plaque formation.