RESUMO
Recent imaging studies have suggested that macular pigment is decreased centrally in macular telangiectasia type 2 (MT2). The uptake of xanthophyll pigment into the macula is thought to be facilitated by a xanthophyll-binding protein (XBP). The Pi isoform of glutathione S-transferase (GSTP1) represents one such XBP with high binding affinity. This case-control study aimed to determine whether two common single-nucleotide polymorphisms (SNPs) of GSTP1 were associated with MT2. DNA samples from 39 cases and 21 controls were collected. Two polymorphic sites of Ile105Val and Ala114Val in exons 5 and 6 respectively, of the GSTP1 gene were analysed. Comparison of alleles and genotypes between cases and controls indicated that there were no statistically significant differences for either the Ile105Val SNP (P=0.43) or the Ala114Val SNP (P=0.85), or for any combinations; however, the homozygous at-risk genotype (GG) of the Ile105Val SNP was present in 8% of cases but absent in controls. This study found no statistically significant association between two common GSTP1 SNPs and MT2; however, a trend towards a greater frequency of the GG genotype of the Ile105Val SNP in cases is of great interest. The biological plausibility of disturbed macular pigment uptake in MT2 makes GSTP1 an excellent candidate gene. Further investigation is warranted in future studies of MT2.
Assuntos
Glutationa S-Transferase pi/genética , Macula Lutea/irrigação sanguínea , Polimorfismo de Nucleotídeo Único , Vasos Retinianos , Telangiectasia/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Frequência do Gene , Genótipo , Homozigoto , Humanos , Masculino , Pessoa de Meia-IdadeAssuntos
Ascomicetos/patogenicidade , Coriorretinite/microbiologia , Fungos Mitospóricos/patogenicidade , Transplante de Células-Tronco/efeitos adversos , Adulto , Antifúngicos/uso terapêutico , Ascomicetos/isolamento & purificação , Coriorretinite/tratamento farmacológico , Coriorretinite/etiologia , Angiofluoresceinografia , Humanos , Macula Lutea/microbiologia , Masculino , Fungos Mitospóricos/isolamento & purificação , Onicomicose/tratamento farmacológico , Triazóis/uso terapêuticoRESUMO
PURPOSE: To assess retinal function in individuals with type 2 diabetes with no retinopathy or nonproliferative diabetic retinopathy (NPDR) and determine the relationship between retinal function and retinal vascular caliber. METHODS: A full-field electroretinogram (ERG) and retinal vascular caliber measurements were performed in subjects with nonproliferative diabetic retinopathy (NPDR, n = 10), diabetic subjects without retinopathy (no-DR, n = 18), and normal control subjects (n = 18). The response amplitudes and implicit times of scotopic and photopic ERG and the retinal arteriolar and venular calibers were compared among the study groups. The relationships between ERG parameters and retinal vascular calibers were determined. RESULTS: There were statistically significant differences between diabetic (no-DR and NPDR groups) and control subjects in the amplitudes and implicit times of rod-derived ERG responses, but not in the cone-derived ERG responses. All the oscillatory potential (OP) components (OP1-OP4) were significantly reduced in amplitude and increased in implicit time in the no-DR and NPDR groups. No significant difference was found in any of the ERG parameters between the no-DR and NPDR groups. Of all the ERG parameters examined, only OP4 amplitude correlated significantly with the retinal arteriolar caliber (r = -0.556, P = 0.006). None of the OP components correlated significantly with retinal venular caliber. CONCLUSIONS: Significant retinal dysfunction was demonstrated in all diabetic patients, even in those without clinically detectable retinopathy, with the rod system being predominantly affected. OP4 amplitude correlates with retinal arteriolar caliber in diabetic patients, suggesting a correlation between retinal neuronal dysfunction and microvasculature changes.
