Preperimetric glaucoma pathophysiological study part3: Association between EDNRA genotype and the effect of a prostaglandin analogue on ocular blood flow

Abstract

Purpose: To investigate association between polymorphisms of endothelin receptor type A (EDNRA) and the response of a prostaglandin (PG) analogue on optic nerve head (ONH) blood flow in eyes with preperimetric glaucoma (PPG).

Methods: In this prospective multicenter study, all patients were treated with a topical prostaglandin (PG) analogue. Diagnosis was performed by glaucoma specialists between August 2012 and April 2014. We obtained a range of ONH blood flow data with laser speckle flowgraphy (LSFG) in 106 eyes of 106 PPG patients (mean 52.5 ± 14.3 years old) treated with tafulprost; changes in ONH mean blur rate (MBR), a parameter of LSFG that represents relative blood flow, before and 90-120 minutes after the treatment were determined (MBR Change) upon enrollment. The genotype (A/A, A/G, and G/G) of a single-nucleotide polymorphism (SNP) in the EDNRA gene (rs6841581) was also determined. Then, association between MBR and SNP genotypes was analyzed.

Results: The MBR Change in response to tafluprost was significantly higher in PPG with A/A genotype (3 eyes, 112.58 ± 12.08 %) than in those with A/G (52 eyes, 99.95 ± 6.02 %; p < 0.01) and G/G (52 eyes, 98.92 ± 5.92%; p < 0.001). Meanwhile, no significant differences in the MBR Change were detected between A/G and G/G genotypes (p = 0.67). There were no detectable differences in other clinical parameters (age, intraocular pressure, mean arterial pressure, and percent intraocular pressure reduction rate) between the three genotypes.

Conclusions: A SNP in the EDNRA gene, rs6841581, was associated with the ONH MBR Change in response to tafluprost in PPG patients. The genotype of the EDNRA SNP may influence the effect of tafulprost on ONH blood flow in eyes with PPG.