The relation between keratoconus and plasma levels of MMP-2, zinc, and SOD.

Purpose: To evaluate the levels of matrix metalloproteinase-2 (MMP-2), superoxide dismutase (SOD), and zinc in plasma taken from patients with keratoconus and to investigate the likely association between these factors and keratoconus.

Methods: A total of 36 patients with keratoconus and 40 control subjects at the Department of Ophthalmology, Faculty of Medicine, Gaziosmanpaşa University, were included in the study. Plasma levels of zinc were determined with atomic absorption spectrometry for all the subjects. Measurements of plasma MMP-2 levels were performed by the enzyme-linked immunosorbent assay method. Total plasma (Cu/Zn and Mn) SOD activity was also determined photometrically.

Results: The plasma concentrations of zinc and MMP-2 were significantly lower in patients with keratoconus than in the healthy controls (P < 0.001). Total plasma SOD levels were significantly higher in patients with keratoconus than in the healthy controls (P < 0.001).

Conclusions: We detected reduced plasma levels of zinc and MMP-2, and enhanced plasma levels of SOD in patients with keratoconus compared with the healthy subjects. The data presented provide insight into the potential role these molecules may play in the etiopathogenesis of this disease.