ABSTRACT
BACKGROUND: To determine plasma ephrin-A1 and VEGF165 levels in a cohort of diabetic retinopathy patients. METHODS: Plasma ephrin-A1 and VEGF165 levels in fifty-five subjects including 19 individuals without diabetes (non-DM), 16 patients with diabetes (DM) but without diabetic retinopathy, and 20 patients with diabetic retinopathy (DR), were determined by ELISA. Serum creatinine, total cholesterol, fasting blood glucose and HbA1c were also measured. One-way ANOVA, Kruskal-Wallis Test, Mann-Whitney U Test corrected by Bonferroni, Pearson Correlation Analysis and Spearman Correlation Coefficient Analysis were used for data analysis. RESULTS: Ephrin-A1 expression could be detected in human plasma with an average of 1.52 ± 0.43 (mean ± SEM) ng/ml. In DR subjects, the plasma ephrin-A1concentration was 3.63 ± 4.63 ng/ml, which was significantly higher than that of the other two groups (non-DM: 0.27 ± 0.13 ng/ml, DM: 0.35 ± 0.34 ng/ml). The expression of VEGF165 in human plasma was 34.00 ± 42.55 pg/ml, with no statistical difference among the three groups. There was no correlation between ephrin-A1 and VEGF165 in human plasma, but there was a correlation between plasma ephrin-A1 and duration of diabetes. CONCLUSIONS: Plasma ephrin-A1 was highly expressed in patients with diabetic retinopathy, and there was no difference of plasma VEGF165 expression in patients with diabetic retinopathy compared to the other two groups, suggesting that changes of plasma ephrin-A1 may be a more sensitive biomarker than plasma VEGF165 in detecting diabetic retinopathy.
Subject(s)
Diabetes Mellitus, Type 2 , Diabetic Retinopathy , Biomarkers , Cohort Studies , Diabetic Retinopathy/diagnosis , Ephrin-A1 , HumansABSTRACT
PURPOSE: Little is known about retinal neuronal loss in the retinas of diabetic mice. The purpose of this study was the quantitative assessment of retinal neural cell number in diabetic mice. METHODS: Five-week-old C57BL/6 mice were used as a diabetic model with streptozotocin. Mice were studied over the course of 6 and 12 weeks after the onset of diabetes. Intraocular pressure (IOP) was measured with a noninvasive TonoLab tonometer. The retinal ganglion cells (RGCs) were counted at two different time points after the induction of diabetes and examined using the immunofluorescence technique and quantitative analysis. RESULTS: The diabetic mice had significantly elevated IOP levels at 6 and 12 weeks after the onset of diabetes compared with the age-matched control mice (p<0.01 and p<0.001, respectively). The temporal course of Brn3a+ RGC and Neuronal Nuclei+RGC (NeuN+ RGC) loss induced by intraperitoneal injection of streptozotocin followed a similar trend. At 6 and 12 weeks after the onset of diabetes, the number of Brn3a+ RGCs (p<0.05 at 6 weeks; p<0.001 at 12 weeks) and NeuN+ RGCs (p<0.05 at 6 weeks; p<0.001 at 12 weeks) was significantly lower in diabetic mice than age-matched control mice. In the retinal flatmounts, the number of Brn3a+ RGCs (p<0.05 at 6 weeks, p<0.01 at 12 weeks) was also significantly lower in diabetic mice than control mice. The IOP in diabetic mice was negatively related with RGCs in cross sections. The cut-off value of IOP was 14.2 mmHg for diabetes. CONCLUSIONS: This is a specific quantitative study of neural cell loss in the retina during diabetes. These data suggest that retinal neural cell reduction occurs in diabetic mice. It indicates that RGC loss may be an important component of diabetic retinopathy.
Subject(s)
Diabetes Mellitus, Experimental/pathology , Diabetic Retinopathy/pathology , Retinal Ganglion Cells/pathology , Animals , Apoptosis , Biomarkers/analysis , Cell Count , DNA-Binding Proteins , Diabetes Mellitus, Experimental/complications , Diabetes Mellitus, Experimental/metabolism , Diabetic Retinopathy/complications , Diabetic Retinopathy/metabolism , Disease Models, Animal , Intraocular Pressure , Male , Mice , Mice, Inbred C57BL , Microscopy, Fluorescence , Nerve Tissue Proteins/analysis , Nerve Tissue Proteins/biosynthesis , Nuclear Proteins/analysis , Nuclear Proteins/biosynthesis , Ocular Hypertension , Retinal Ganglion Cells/metabolism , Tonometry, Ocular , Transcription Factor Brn-3A/analysis , Transcription Factor Brn-3A/biosynthesisABSTRACT
PURPOSE: To study whether aqueous humor (AH) and plasma adiponectin (APN) levels were altered in proliferative diabetic retinopathy (PDR). MATERIALS AND METHODS: After excluding subjects with hypertension, hyperlipidaemia, nephropathy, coronary heart disease, heart and renal failure, 20 consecutive type 2 diabetes mellitus (DM) PDR patients and 20 consecutive age-matched non-diabetic and senile cataract (non-DM) controls were enrolled in this study. AH APN and plasma APN concentrations were determined by enzyme-linked immunosorbent assay (ELISA). The expression of AdipoR1/R2 mRNA in peripheral blood mononuclear cells (PBMCs) was measured by real-time polymerase-chain reaction (PCR). The correlations between two parameters, including plasma and AH APN, AdipoR1/R2, plasma insulin and plasma glucose, were analyzed by Pearson's correlation. RESULTS: In non-DM subjects, the APN concentration in AH was 1.26 ± 0.56 ng/ml, approximately 1/2500 of that in plasma (3.15 ± 1.36 µg/ml). The averaged AH APN concentration in PDR patients was significant higher than that of the non-DM controls (5.29 ± 4.09 ng/ml vs. 1.26 ± 0.56 ng/ml, p < 0.001). Plasma total APN was not correlated with AH APN in the PDR patients, controls or all subjects. No significant difference was observed in plasma total APN levels and AdipoR1/R2 mRNA levels in PBMCs between the PDR patients and the controls (p > 0.05). CONCLUSION: Differences in APN concentration between AH and plasma suggest blood-retinal barrier (BRB) plays a key role in maintaining intraocular APN homeostasis. The high APN level in AH may be associated with PDR.
