Association of macular pigment optical density with early stage of non-proliferative diabetic retinopathy in Chinese patients with type 2 diabetes mellitus

AIM：To detect the association between macular pigment optical density（MPOD）,which reflects the antioxidant ability of retina,and diabetic retinopathy（DR）and to investigate the correlated factors of MPOD.METHODS： Totally 435 subjects of urban Chinese were recruited to the study and divided into 3 groups： non-diabetes mellitus controls（NDM）,diabetic patients without retinopathy（DWR）,and patients with early stage of non-proliferative diabetic retinopathy（DR）.Demographic and lifestyle characteristics were ascertained by questionnaire.A food-frequency questionnaire,general physical and ophthalmic examinations were completed for all participants.MPOD was measured by heterochromatic flicker photometry.Foveal thickness was measured by optical coherence tomography.The difference of MPOD among 3 groups was analyzed by analysis of covariance.The correlation analyses of MPOD with the candidate influence factors were assessed using the generalized estimating equations（GEE） model.RESULTS： Of the 435 participants,34 could not perform the MPOD measurements.Final analysis included 401 subjects,including 48 were in DR group,134 in DWR group,and 219 in NDM group.MPOD was not significantly different among DR（0.49 ±0.21）,DWR（0.45 ±0.21）,and NDM（0.49±0.17） groups（P=0.24） after adjustment for fasting plasma glycemia,central foveal thickness,green vegetables,Chinese wolfberry,carotene and vitamin E.For all the 401 participants included,MPOD was positively associated with central foveal thickness（E=0.0007,P=0.001）,Chinese wolfberry（E=0.0345,P=0.01）,and green vegetables（E=0.0596,P〈0.001） intake.CONCLUSION： The data suggest that MPOD level is not statistically significantly influenced by the onset of diabetes or early stage of DR in the studied population.MPOD level is positively associated with thicker central foveal thickness and higher intake of foods containing carotenoids.

Association of candidate gene polymorphisms with diabetic retinopathy in Chinese patients with type 2 diabetes

●AIM:To investigate the association between a set of six candidate genes and the risk of diabetic retinopathy(DR)in an urban community cohort of Chinese patients with type 2 diabetes mellitus(T2 DM).●METHODS:A population-based cross-sectional study.The diabetic subjects were recruited from an urban community in Beijing and categorized into groups of proliferative diabetic retinopathy(PDR),non-proliferative diabetic retinopathy(NPDR),or diabetic without any retinopathy(DWR)based on the fundus photography and duration of diabetes.Six candidate genes,including advanced glycation end product specific receptor(AGER),aldose reductase(AKR1 B1),inducible nitric oxide synthase(i NOS),pigment epithelium derived factor(PEDF),tumor necrosis factor-alpha(TNF-α),and paraoxonase 1(PON1),were chosen based on Meta-analysis of genetic association studies for DR and biochemical pathways implicated in DR progression.The allele and genotype distribution of 21 functional singlenucleotide polymorphisms(SNPs)in those 6 candidate genes were investigated using MassARRAY genotyping system.●RESULTS:Among 1461 diabetic patients recruited from community,569 were selected in following genotyping analysis,including 97 patients with PDR,217 with NPDR,and 255 with DWR.For the promoter variant rs1051993 in AGER gene,the distribution of allele and genotype in PDR group differed from that in DWR group(allele:P=0.011;genotype:P=0.01).Compared with DWR,patients with PDR had lower frequencies of heterozygous genotype GT(9.8%for DWR,1%for PDR,OR:0.10,95%CI:0.01-0.72)and minor allele T(4.9%for DWR,0.5%for PDR,OR:0.10,95%CI:0.01-0.75).In multivariate model,the distribution of genotype for rs1051993 in PDR group was significantly different from that in DWR group(GT vs GG:OR:0.07,95%CI:0.01-0.61,P<0.001).No association with DR was observed in other genotyped SNPs.●CONCLUSION:The data suggest a significant association of the promoter variant rs1051993 in AGER gene with PDR in Chinese cohort with T2DM.

Association of choroidal thickness with early stages of diabetic retinopathy in type 2 diabetes

AIM：To assess the correlation between choroidal thickness（CT） and the early stages of diabetic retinopathy（DR） in type 2 diabetic patients.METHODS：We divided 83 diabetic patients（51-80 years of age;50 females） into non diabetic retinopathy group（NDR） and mild/moderate nonproliferative diabetic retinopathy（NPDR） group,and compared them with 26 non-diabetic control subjects（51-78 years of age;16 females）.Subfoveal choroidal thickness（SFCT） and parafoveal choroidal thickness（PFCT） were measured using enhanced depth imaging spectral-domain optical coherence tomography（EDI-OCT）.Ocular health status,disease duration,body mass index,and hemoglobin A1c（Hb A1c） were recorded.RESULTS：The mean ages of the NDR,NPDR,and control groups were 68.0±6.9y,67.8±6.4y,and 65.1±6.3y,respectively（P=0.17）.Pearson correlation of the right and left eyes for the control subjects was 0.95 and for the NDR subjects was 0.93.SFCT for the right eyes of the controls was 252.77± 41.10 μm,which was significantly thicker than that of the right eyes in NDR group（221.51±46.56 μm） and the worse eyes of the NPDR group（207.18±61.87 μm;ANOVA,P〈0.01）.In the diabetic patients pooled together,age was the only variable significantly associated with SFCT（multiple linear regression analysis,P=0.01）.CONCLUSION：CT decreased significantly in the NDR and mild/moderate NPDR eyes compared with the control eyes.Age is significantly associated with SFCT in the diabetic patients.Diabetic choroidopathy may be present before clinical retinopathy.