Attenuated levels of pro-inflammatory markers in diabetic retinopathy patients undergoing treatment with antihyperglycemic and antihypertensive drugs

OBJECTIVE:

This study aimed to assess the circulating levels of activated nuclear factor kappa B p65 and monocyte chemotactic protein-1 in diabetic retinopathy patients who were taking antihyperglycemic and antihypertensive drugs.

METHODS:

In total, 235 healthy controls and 371 Type 2 diabetic patients [171 without retinopathy (DNR) and 200 patients with retinopathy (diabetic retinopathy)] were recruited for this study. Plasma and the nuclear fraction of peripheral blood mononuclear cells were isolated for the quantification of the monocyte chemotactic protein-1 and nuclear factor kappa B p65 levels, respectively.

RESULTS:

Non-medicated diabetic retinopathy patients had significantly higher levels of activated nuclear factor kappa B p65 and plasma monocyte chemotactic protein-1 than DNR patients. Diabetic retinopathy patients who were taking antihyperglycemic and antihypertensive drugs showed significant reductions in both the nuclear factor kappa B p65 and monocyte chemotactic protein-1 levels compared with the non-medicated patients.

CONCLUSION:

This study demonstrated the significant attenuation of both the nuclear factor kappa B p65 and circulating monocyte chemotactic protein-1 levels in diabetic retinopathy patients taking antihyperglycemic and antihypertensive drugs.     

Blood antioxidant parameters in patients with diabetic retinopathy

It has been postulated that enhanced generation of reactive oxygen species (ROS) may take part in a pathogenesis of diabetic microvascular complication - retinopathy. There are two types of diabetic retinopathy, non-proliferative (simplex) and proliferative. ROS are anihilated by an intracelluar enzymatic system composed mainly of glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT). Beta-carotene, tocopherols and ascorbic acid are major components of serum antioxidants. All serum antioxidants are usually measured together as total antioxidant status (TAS). Erythrocyte activities of GPx, SOD, CAT and TAS were measured in diabetic patients without retinopathy, with non-proliferative and proliferative retinopathy. Obtained results were correlated with a period of diabetic history and a period of insulin treatment. SOD was significantly elevated in diabetics with non-proliferative retinopathy compared to patients without retinopathy. TAS was significantly lower in patients with proliferative retinopathy than in diabetics not developing retinopathy. Only CAT was significantly negatively correlated with the period of insulin treatment. This significant negative correlation was also observed in a subgroup of patients with proliferative retinopathy.     

Urinary 6-sulfatoxymelatonin level in diabetic retinopathy patients with type 2 diabetes

Melatonin is a powerful antioxidant. Decreased melatonin excretion has been reported to be associated with several oxidative stress-related diseases. The urinary metabolite of melatonin, 6-sulfatoxymelatonin (aMT6s), has proved to be a very reliable index of melatonin production. The present study aims to evaluate the level of urinary aMT6s in patients with type 2 diabetes mellitus and diabetic retinopathy. Urine samples were collected from 10 patients with diabetes and no diabetic retinopathy (NDR), 19 patients with nonproliferative diabetic retinopathy (NPDR), 38 patients with proliferative diabetic retinopathy (PDR), and 16 subjects without diabetes mellitus, who served as controls. The level of aMT6s in specimens was assayed by a commercial aMT6s ELISA kit, creatinine levels were also measured for each sample to get urinary aMT6s/creatinine ratio. Creatinine-adjusted urinary aMT6s values were compared among four groups. The urinary aMT6s (mean ± SD) levels were 9.95 ± 2.42, 9.90 ± 2.28, 8.40 ± 1.84 and 5.58 ± 1.33 ng/mg creatinine in the controls and in patients with NDR, NPDR, or PDR, respectively. The urinary aMT6s level of the PDR group was significantly lower than that of the control, NDR and DR groups. No significant difference was found among the control, NDR and DR groups. After adjustment for various factors (age, smoking, cancer, and coronary heart disease) that may influence the aMT6s level, the odds-ratio of urinary aMT6s comparing PDR patients to controls was 0.246 (95% confidence interval = 0.108-0.558, P = 0.001). Therefore, the urinary aMT6s level is significantly decreased in diabetic patients with PDR but not in diabetic patients without PDR, which indicates that decreased urinary aMT6s level may be associated with the pathogenesis of PDR.     

频域光学相干断层扫描在早期糖尿病视网膜病变检测中的应用

目的:利用频域光学相干断层扫描(OCT)定性、定量检测并分析正常人群和眼底镜下无糖尿病视网膜病变的糖尿病患者的黄斑区视网膜的形态、厚度等改变,为糖尿病视网膜病变的早期发现及随访提供可靠的检测手段.方法:采用Cirrus HD-OCT的512×128扫描模式及5线高清扫描模式检测糖尿病患者双眼黄斑视网膜平均厚度、黄斑中心凹视网膜厚度及黄斑部9个分区的视网膜厚度,与正常对照组进行比较,并对结果行统计学分析.结果:糖尿病患者60例(120只眼),根据糖尿病视网膜病变分期标准,眼底均表现为无糖尿病视网膜病变(NDR).糖尿病NDR组与正常对照组相比,黄斑区视网膜厚度外环的鼻侧和颞侧与正常眼之间差异有统计学意义.其余各区的视网膜厚度与正常眼之间没有差异.结论:NDR组与正常对照组相比,黄斑区视网膜厚度外环的鼻侧和颞侧与正常眼之间有差异.这为在临床上早期发现糖尿病视网膜病变提供了客观依据,并便于随访观察.     

Association of the polymorphism in manganese superoxide dismutase gene with diabetic retinopathy in Chinese type 2 diabetic patients

OBJECTIVE: To investigate the association of the polymorphism in manganese superoxide dismutase (Mn-SOD) gene in Chinese type 2 diabetic patients with diabetic retinopathy. METHODS: The Ala(-9)Val polymorphism of the Mn-SOD gene was determined by polymerase chain reaction and direct sequencing in 198 normal control subjects and 264 patients with type 2 diabetes mellitus, among them there were 139 non-diabetic retinopathy (NDR) subjects and 125 subjects with diabetic retinopathy (DR). RESULTS: There was no statistic difference in the frequencies of VV genotype and V allele between the type 2 diabetic group and the control group. However, the frequencies of VV genotype and V allele were significantly higher in the DR group than that in the NDR group (chi-square (2)=5.015, P=0.025?chi-square (2)=10.253, P=0.001),but there was no statistic difference in the NDR group compared with the control group (P > 0.05). The presence of V allele was shown to be associated with diabetic retinopathy (OR=1.96, 95%CI: 1.29-2.97). Furthermore, the subjects carrying the VV genotype had lower serum Mn-SOD level (P=0.025) and had a tendency of higher total serum SOD activity, but this tendency had no statistic significance. CONCLUSION: The Ala(-9)Val polymorphism in the Mn-SOD gene may not be related to the etiology of type 2 diabetes, but it seems to contribute to the development of diabetic retinopathy in Chinese type 2 diabetic patients.     

Cytokine profile of peripheral blood in type 2 diabetes mellitus patients with diabetic retinopathy

To evaluate the usefulness of cytokine levels of peripheral blood in diabetic retinopathy (DR), demographic and biochemical parameters including low-density lipoprotein (LDL) diameter as well as cytokine profiles were analyzed in 74 patients with type 2 diabetes mellitus (DM), with DR (n=46) or without DR (n=28). DM duration was longer in the patients with DR than without (p<0.001). Serum glucose (p=0.005) and total cholesterol (p=0.029) levels were higher in DM patients with DR than DM patients without DR. Plasma LDL diameter, interleukin-6 (IL-6), and interleukin-8 (IL-8) showed significant differences among the different degrees of DR severity in analysis of variance (ANOVA) with no definite trend. The risk of DR in DM patients was decreased by an increase of interleukin-10 (IL-10) level [odds ratio (OR)=0.152; confidence interval (CI): 0.028-0.817]. Plasma LDL diameter was smaller and IL-6 and tumor necrosis factor-alpha (TNF-alpha) levels were higher in DM patients with proliferative diabetic retinopathy (PDR) compared to those with non-proliferative diabetic retinopathy (NPDR) (p<0.05). We found that higher IL-10 levels were related to lower risk of DR in DM patients. Levels of IL-6 and TNF-alpha as well as LDL diameter may be helpful in the prediction of PDR in DM patients with DR.     

糖尿病视网膜病变患者脂肪酸水平与胰岛素抵抗

近年的研究表明,胰岛素抵抗（insulin resistance,IR）和高胰岛素血症（IRS）对糖尿病及其微血管病变的发病具有重要的作用。脂肪酸不仅是机体代谢和细胞膜结构的重要成分,而且也是一种信使分子,它在IR和视网膜病变发病中的作用日益引起人们的重视。本文旨在探讨2型糖尿病患者血浆非酯化脂肪酸（NEFA）代谢紊乱与其IR和视网膜病变发生的关系。     

Suppression of diabetic retinopathy with angiopoietin-1

Diabetic retinopathy remains a leading cause of irreversible blindness. A critical early pathology in the disease is the adhesion of leukocytes to the retinal vasculature, a process that occurs, in part, via intercellular adhesion molecule-1. Once leukocyte adhesion occurs, endothelial cell injury ensues, as does blood-retinal barrier breakdown. Here we show that angiopoietin-1 can prevent and reverse these diabetic retinal vascular changes in both new and established diabetes. Angiopoietin-1, when given intravitreally to newly diabetic rats, normalized retinal vascular endothelial growth factor (VEGF) and intercellular adhesion molecule-1 mRNA and protein levels, leading to reductions in leukocyte adhesion, endothelial cell injury, and blood-retinal barrier breakdown. When an adenovirus coding for angiopoietin-1 was given systemically to mice with established diabetes, it similarly inhibited leukocyte adhesion and endothelial cell injury and blood-retinal barrier breakdown. These changes coincided with reductions in retinal eNOS, nitric oxide, Akt (protein kinase B), and MAP kinase activity, known mediators of VEGF bioactivity and leukocyte adhesion. When endogenous VEGF bioactivity was inhibited with a soluble Flt-1/Fc chimera, retinal Akt kinase activity was significantly reduced in vivo. Taken together, these data document new vascular and anti-inflammatory bioactivities for angiopoietin-1 and identify it as the first naturally occurring protein that directly protects the retinal vasculature in diabetes.     

Involvement of RhoA/ROCK1 signaling pathway in hyperglycemia-induced microvascular endothelial dysfunction in diabetic retinopathy

Diabetic retinopathy (DR) is a well-known serious complication of diabetes mellitus (DM), and can eventually advance to end-stage blindness. In the early stage of DR, endothelial cell barrier disorganized primarily and tight junction (TJ) protein composition transformed subsequently. The small GTPase RhoA and its downstream effector Rho-associated coiled-coil containing protein kinase 1 (ROCK1) regulate a mass of cellular processes, including cell adherence, proliferation, permeability and apoptosis. Although RhoA inhibitors have provided substantial clinical benefit as hypertonicity therapeutics, their use is limited by complex microenvironment as DR. While ample evidence indicates that TJ can be influenced by the RhoA/ROCK1 signaling, the underlying mechanisms remain incompletely understood. Here, we have uncovered a significant signaling network involved in diabetic retinal microvascular endothelial dysfunction (RMVED). Our results indicated that the activation of RhoA/ROCK1 pathway due to high glucose played a key role in microvascular endothelial cell dysfunction (MVED) by way of directly inducing TJ proteins over-expression during DR. We demonstrated that inhibition of RhoA/ROCK1 may attenuate the hypertonicity of endothelial cell caused by high glucose microenvironment meanwhile. Besides, chemical and pharmacological inhibitors of RhoA/ROCK1 pathway may partly block inflammation due to DR. Simultaneously, the apoptosis aroused by high glucose was also prevented considerably by fasudil, a kind of pharmacological inhibitor of RhoA/ROCK1 pathway. These findings indicate that RhoA/ROCK1 signaling directly modulates MVED, suggesting a novel therapeutic target for DR.     

Intraocular matrix metalloproteinase 2 and 9 in patients with diabetes mellitus with and without diabetic retinopathy

Introduction

We aimed to investigate activities of metalloproteinases 2 (MMP-2) and MMP-9 in aqueous humour of patients with diabetes mellitus with various stages of diabetic retinopathy.

Material and methods

We included 36 samples of aqueous humour of patients suffering from diabetes mellitus, undergoing routine cataract surgery. Seven of them suffered from proliferative diabetic retinopathy (PDR), 3 had diabetic maculopathy and the remaining 26 had background or minimal background retinopathy only. Metalloproteinases 2 and MMP-9 activities in aqueous humour were measured by gelatin zymography combined with the densitometric imaging system. Total protein content in aqueous humour samples was also assessed.

Results

Metalloproteinases 2 activities were present in almost all samples of aqueous humour (32 of 36) and were 2.6-fold higher in patients who suffered from diabetic ocular complications (p < 0.0001). Activities of MMP-2 correlated well with the duration of the disease (correlation = 0.37, p = 0.03) and tended to correlate with total protein levels in aqueous humour (correlation = 0.43, p = 0.06). Metalloproteinases 9 activities were observed only in 2 of 7 patients with proliferative diabetic disease and the enzyme was absent from aqueous humour samples of patients without proliferative retinopathy.

Conclusions

Increased activities of MMP-2 in aqueous humour of patients with PDR may be related to the disease process and support the hypothesis that MMP-2 may be of particular importance in diabetic retinal neovascularization. MMP-9 may be activated at a certain disease stage only.     

糖尿病视网膜病变黄斑拱环形态改变的临床研究

目的客观评价糖尿病视网膜病变（DR）患者黄斑拱环结构改变的形态特征,总结黄斑拱环形态变化、荧光渗漏及黄斑区视网膜厚度对视力的影响因素。方法患者按有无眼底改变分为3组,糖尿病视网膜病变组（DR组）38例65只眼,2型糖尿病无DR眼底改变组（非DR组）16例29只眼,正常组17例33眼。三组病例均先行眼底荧光素血管造影（FFA）检查,后行光学相干断层扫描（OCT）眼底黄斑部放射状扫描检查。结果三组之间黄斑拱环形态变化比较,有显著差异（P=0．0003）,黄斑中心1mm直径视网膜厚度有显著差异（P=0．0007）。DR组患者拱环形态与荧光渗漏程度显著相关（P=0．0003）,黄斑拱环形态与黄斑中心1mm直径视网膜厚度显著相关（P=0．0063）,荧光渗漏程度与黄斑中心1mm直径视网膜厚度显著相关（P=0．0046）。DR组患者黄斑拱环形态、荧光渗漏和黄斑中心1mm直径视网膜厚度变化与最佳矫正视力无相关性（P=0．076,P=0．067,P=0．128）。结论DR患者黄斑拱环形态改变、渗漏程度及黄斑中心视网膜厚度是相互影响和互为因果,黄斑拱环形态变化特征为进一步选择和调整治疗手段提供了准确依据。     

Decrease in inflammatory cardiovascular risk markers in hyperlipidemic diabetic patients treated with fenofibrate

The goal was to investigate the effect of micronized fenofibrate, a hypolipidemic drug, on inflammatory markers and proinsulin in patients with type 2 diabetes who had hyperlipidemia. Thirty-nine patients were treated with micronized fenofibrate (200 mg/day for 12 wk). Erythrocyte sedimentation rate (ESR), fibrinogen, high-sensitivity C-reactive protein (hs CRP), and proinsulin levels were measured at baseline and after 12 wk of therapy. Micronized fenofibrate significantly reduced serum triglyceride, cholesterol, and uric acid levels (all p <0.0001) and increased high-density lipoprotein (HDL)-cholesterol (p <0.001) and creatinine levels (p <0.0001). Micronized fenofibrate also significantly decreased fibrinogen (421 +/- 152 vs 344 +/- 81 mg/dl, p <0.001), hs-CRP (3.3 +/- 3.3 vs 2.1 +/- 1.8 mg/L, p <0.01), and ESR (19.1 +/- 24.8 vs 9.7 +/- 8.7 mm/hr, p <0.01), but did not change proinsulin levels. The correlations among changes of hs-CRP, fibrinogen, and ESR were high. Although correlation among the decreases in inflammatory markers (ESR, fibrinogen, and hs-CRP) was significant, there was no significant correlation between the changes of lipid profile and inflammatory markers. In conclusion, after 12 wk, micronized fenofibrate therapy significantly decreased 3 inflammatory markers (hs-CRP, ESR, and fibrinogen) and improved the lipid profile by decreasing serum triglyceride, cholesterol, and non-HDL-cholesterol levels and increasing HDL-cholesterol; however, it did not change serum proinsulin level, a pancreatic stress marker.     

Association analysis of nine candidate gene polymorphisms in Indian patients with type 2 diabetic retinopathy

Background  

Diabetic retinopathy (DR) is classically defined as a microvasculopathy that primarily affects the small blood vessels of the inner retina as a complication of diabetes mellitus (DM).It is a multifactorial disease with a strong genetic component. The aim of this study is to investigate the association of a set of nine candidate genes with the development of diabetic retinopathy in a South Indian cohort who have type 2 diabetes mellitus (T2DM).     

Serum miR-122 levels correlate with diabetic retinopathy

Clinical and Experimental Medicine - Diabetic retinopathy is the most severe ocular complication of diabetes and may lead to visual disability and blindness. Proliferative diabetic retinopathy...     

Effect of intravitreal bevacizumab on vascular endothelial growth factor expression in patients with proliferative diabetic retinopathy

Purpose

To investigate the effect of bevacizumab (Avastin; Genentech, San Francisco, CA, USA) on vascular endothelial growth factor (VEGF) expression and inflammation in fibrovascular membranes in patients with proliferative diabetic retinopathy (PDR).

Materials and Methods

Fibrovascular membranes from 19 eyes of 18 patients with PDR were studied using immunohistochemistry and analyzed in the following 3 groups; group 1: 4 inactive PDR eyes, group 2: 10 active PDR eyes treated preoperatively with adjunctive intravitreal bevacizumab, group 3: five active PDR eyes not treated preoperatively with bevacizumab. Immunohistochemical staining for VEGF, CD31 and CD68 were done.

Results

The immunoreactivity to VEGF and CD 31-positive blood vessels was significantly higher in membranes from group 3 than group 1 (p = 0.007 for VEGF, 0.013 for CD 31-positive vessels). Intravitreal bevacizumab caused a reduction in VEGF expression and vascular densities in 4 out of 10 (40%) excised membranes from eyes with PDR. However, six membranes (60%) in group 2 still demonstrated relatively strong VEGF expression and high vascular density. Infiltration of macrophages was observed in 16 out of the 19 membranes, and the density of macrophages was increased in group 2 compared with group 1 (p = 0.043).

Conclusion

Intravitreal bevacizumab injections caused some reduction in VEGF expression and vascular densities in a limited number of active PDR patients. A single intravitreal bevacizumab injection may not be enough to induce complete blockage of VEGF and pathologic neovascularization in active PDR patients. Repeated injections, panretinal photocoagulation and/or PPV may be necessary following intravitreal bevacizumab to reinforce the anti-VEGF effect of the drug.