Plasma Levels of Matrix Metalloprotease MMP-9 and Tissue Inhibitor TIMP-1 in Caucasian Patients with Polypoidal Choroidal Vasculopathy

BACKGROUND: Matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinases 1 (TIMP-1) are regulating enzymes of the extracellular matrix. A systemic imbalance of MMP-9 and TIMP-1, thought to reflect an imbalance of the extracellular matrix homeostasis, is previously associated with polypoidal choroidal vasculopathy (PCV) in Asian patients. Previous studies suggest inter-ethnical differences in the genetic background and etiology of PCV. To further explore this issue, we studied the plasma levels of MMP-9 and TIMP-1 in Caucasian patients with PCV and compared to healthy age-matched controls.

METHODS: For this prospective case-control study, 60 participants were recruited who were either patients with PCV (n = 26) or healthy controls (n = 34). All participants underwent detailed clinical examination. We sampled fresh venous blood, isolated plasma, and quantified plasma concentrations of the extracellular matrix regulators MMP-9 and TIMP-1 using electrochemiluminescence immunoassays.

RESULTS: Plasma levels of MMP-9 (p = 0.4), TIMP-1 (p = 0.9), and MMP-9/TIMP-1 ratio (p = 0.4) did not differ significantly between patients with PCV and healthy controls. No differences appeared after adjusting for influencing co-variates in multivariate analyses.

CONCLUSION: We demonstrate that Caucasian patients with PCV do not have altered levels of plasma MMP-9 or plasma TIMP-1. These findings suggest no strong evidence of a systemic imbalance of the extracellular matrix homeostasis in Caucasian patients with PCV. Our findings are in line with studies of other aspects of PCV that are also subject to significant inter-ethnical differences.