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P. DeSouza Ramalho, A. Pereira da Silva, C. Thyran, M.P. Bicho; Haptoglobin Genotypes and Erythroietin in Diabetic Retinopathy . Invest. Ophthalmol. Vis. Sci. 2005;46(13):401.
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© ARVO (1962-2015); The Authors (2016-present)
Haptoglobin (α 2– sialoglycoprotein) an acute phase inflammatory serum protein expressed by genetic polymorphism (2 alleles, 3 phenotypes) has been associated to diabetic retinopathy (DR). Erythropoietin (EPO) an hematopoietic cytokine is neuroprotective and assists neuronal survival by binding to its receptor (EPOR) in the brain and retina. It is up regulated in ischemic retina in prolipherative DR. Purpose: To study Haptoglobin (Hp) genetic phenotype correlations with EPO serum expression in diabetics with and without retinopathy. Methods: Hp genotypes 1.1, 2,1, 2.2 determined using polyacrylamide gel electrophoresis and EPO serum levels measured by ELISA, in 37 type 2 diabetics and 44 non diabetic controls, age and sex matched. Statistical analysis was carried out using Student "t" test, ANOVA and X2 . Results: A high number of Hp 2.2 genotypes was observed in diabetics with retinopathy (50%) in relation to 2.1 (33.3%) and 1.1 (16.7%). In diabetic group without retinopathy the number of Hp 2.1 genotype individuals was greater ( 72%, p=0.036). EPO levels were high in diabetics compared to the controls (12.07±9.42 mIU/ml vs 9.47±6.57, p=0.151) and higher in diabetics with retinopathy than without (14.00±13.1 vs 10.84±6.11, p=0.332). Hp genotype 2.2 showed high/significant EPO expression compared to other genotypes, p=0,037. Conclusions: Association of high EPO expression with Haptoglobin 2.2 genotype could be a marker of DR suggesting its inflammatory and oxidative nature and, ischemia induced erythropoietin, a neuroprotective mechanism. Further studies are needed to support this hypothesis.
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