Müller cell markers in aqueous humor of patients with type-2 macular telangiectasia.

PURPOSE: To investigate the pathogenesis of type-2 macular telangiectasia (MacTel) by comparing the levels of glial fibrillary acidic protein (GFAP), aquaporin-4 (AQP4), and K+ inwardly rectifying channel 4.1 (Kir4.1) in the aqueous humor of diagnosed patients and individuals who had no ophthalmological disease.

METHODS

This prospective study included nine patients with cataract and MacTel type 2 (group 1) and patients without any ophthalmological pathology other than senile cataract (group 2). We comparatively analyzed the groups' GFAP, AQP4, and Kir4.1 levels in the anterior chamber fluid, which was sampled intraoperatively during the cataract surgery.

RESULTS

The GFAP levels were found to be 601.18 ± 66.19 pg/mL in the patient group and 1059 ± 537 pg/mL in the control group, and the difference was statistically significant. (P = 0.019) The mean AQP4 levels were lower (1.5 ± 1.02 ng/mL) in the patient group than in the control group (2.81 ± 1.19 pg/mL) (P = 0.012). There was no significant difference in terms of the mean Kir4.1 levels between the groups (P = 0.453). There was a significant negative correlation between the postoperative best corrected visual acuity (logMAR) and GFAP and AQP4 (for GFAP; r = -0.473 P = 0.02, for AQP4 r = -0.463 P = 0.023).

DISCUSSION: GFAP and AQP4 levels may be related to glial cell dysfunction and disturbances in retinal fluid balance in the pathophysiology of MacTel type 2.