Soluble CD44 and vascular endothelial growth factor levels in patients with acute primary angle closure

Acute elevation of intraocular pressure (IOP) in acute primary angle closure (APAC) can cause huge damage to the variable cells in the eye; however, the mechanisms that connect the two processes still remain unclear. In this study, we aim to evaluate the levels of soluble CD44 (sCD44) and vascular endothelial growth factor (VEGF) in the aqueous humour of acute primary angle closure patients.

This study included 24 eyes of 24 APAC patients (11 eyes with current APAC and 13 eyes with previous APAC) and 15 eyes of 15 cataract subjects. Clinical data were acquired, and aqueous humour was collected. The levels of sCD44 and VEGF in the aqueous humour were determined by ELISA and magnetic bead immunoassay technique.

The concentrations of the sCD44 and VEGF in the current APAC were 9.9 ± 8.8 ng/ml and 2440.2 ± 2107.1 ng/ml, respectively, which were significantly higher when compared to the previous APAC group (p = 0.001) and cataract (p < 0.001); however, there were no significant differences between the group with previous APAC and with cataract. Higher IOP was associated with higher concentration of sCD44 (Rho = 0.617, p = 0.001). The concentration of the VEGF in aqueous humour of APAC patients was closely related to the sCD44 levels (Rho = 0.752, p < 0.001).

After acute increase of IOP in the APAC, the level of sCD44 and VEGF increased significantly in the aqueous humour. The damage due to high IOP may therefore be mediated through the release of sCD44.