Correlations of AQP4 expression and polymorphism with diabetic retinopathy

The aim of this study was to investigate the relationships of aquaporin 4 (AQP4) rs200498749, rs149465 and rs650217 polymorphisms and gene expression with diabetic retinopathy (DR).

A total of 400 patients with diabetes mellitus (DM) treated in our hospital were enrolled in this study. All subjects were divided into two groups, including DM group (n=200, without DR) and DR group (n=200, with DR). The polymorphisms rs200498749, rs149465 and rs650217 of AQP4 gene were analyzed in the two groups. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect gene expression, and statistical analysis was performed in combination with clinical data.

The distribution of alleles of AQP4 rs650217 (p=0.015) in DR group was different from that in DM group, and the frequency of T allele was significantly higher in DR group than DM group. The distribution of genotypes of AQP4 rs149465 (p=0.000) and rs650217 (p=0.000) showed statistically significant difference between DR group and DM group. The frequency of AA genotype of polymorphism rs149465 and CT genotype of polymorphism rs650217 was significantly higher in DR group than DM group. Besides, there was a difference in the distribution of recessive models of AQP4 rs149465 (p=0.023) and rs650217 (p=0.014) between DR group and DM group. DR group exhibited remarkably lowered frequency of AA + AT recessive model of the polymorphism rs149465 and raised frequency of CT + TT recessive model of the polymorphism rs650217. Similarly, a difference was found in the distribution of haplotypes CAT (p=0.014) and CTC (p=0.003) of AQP4 rs200498749, rs149465 and rs650217 between DR group and DM group. The polymorphism rs200498749 of AQP4 gene was significantly correlated with AQP4 gene expression (p<0.05). Meanwhile, the expression of AQP4 gene was clearly higher in patients with CC genotype in DR group (p<0.05). AQP4 polymorphism rs200498749 was related to fasting blood glucose (p=0.000) and hemoglobin A1c (HbA1c) (p=0.000) in DR group, and polymorphism rs650217 had an association with serum creatinine level (p=0.034). AQP4 polymorphisms rs149465 (p=0.023) and rs650217 (p=0.042) were correlated with clinical stage in DR group. In addition, the proportion of patients with AA genotype of rs149465 at stage VI and with TT genotype of rs650217 at stage I rose significantly (p<0.05).

AQP4 gene polymorphism has a potential relationship with the susceptibility and progression of DR.