Increased SCUBE-1 levels in the aqueous humour of patients with pseudoexfoliation syndrome.

Clinical relevance: Pseudoexfoliation syndrome (PXS) is a common age-related disorder associated with glaucoma and cataract. Despite its clinical importance, the pathogenesis of PXS is not yet fully understood.

Background: To evaluate levels of SCUBE-1 (signal peptide, CUB domain, and epidermal growth factor-like domain containing protein 1) in the serum and aqueous humour of patients with PXS in comparison with non-PXS controls.

Methods: This prospective study included patients with and without PXS undergoing phacoemulsification surgery for cataract. Patients with pseudoexfoliative glaucoma were excluded. Aqueous humour samples collected at the beginning of phacoemulsification surgery were analysed by using the sandwich enzyme-linked immunosorbent assay method (human SCUBE-1 enzyme-linked immunosorbent assay kit; Elabscience).

Results: There was a significant difference in mean aqueous humour SCUBE-1 levels between PXS patients (1.69 ± 0.41 ng/µL) and non-PXS controls (0.89 ± 0.33 ng/µL) (p = 0.012). However, the difference in mean serum SCUBE-1 levels was not significant (0.87 ± 0.36 ng/µL and 0.81 ± 0.35 ng/µL, respectively; p = 0.560). There was no significant correlation between aqueous humour and serum SCUBE-1 levels in either group (p > 0.05).

Conclusion: SCUBE-1 is an important marker of ischaemia and oxidative stress. Increased SCUBE-1 levels in the aqueous humour of patients with PXS may indicate a local effect of SCUBE-1 in the pathogenesis of PXS.