Associations Between Diabetic Retinopathy and Plasma Levels of High-sensitive C-reactive Protein or Von Willebrand Factor in Long-term Type 1 Diabetic Patients

Circulatory Biomarkers and Diabetic Retinopathy in Racial and Ethnic Populations

Clinical staging systems for diagnosis and treatment of diabetic retinopathy (DR) must closely relate to endpoints that are both relevant for patients and feasible for physicians to implement. Current DR staging systems for clinical eye care and research provide detailed phenotypic characterization to predict patient outcomes in diabetes but have limitations. Biochemical biomarkers provide a rich pool of potential candidates for new DR staging systems that can be readily measured in accessible fluids. Circulating biomarkers that are specific to the retina and relate to angiogenesis and inflammation have been suggested as relevant for DR. Although there is a lack of multi-ethnic studies evaluating circulatory biomarkers in DR, variability in circulatory biomarkers have been reported in people from different ethnic and racial backgrounds. Therefore, there is a need for future studies to evaluate individual or combinations of biomarkers in diverse populations with DR from different ethnic and racial backgrounds.

Study of the relation between plasma level of von Willebrand factor and diabetic retinopathy in type 2 diabetes

Purpose

Diabetic retinopathy (DR) is a major preventable health complication of type 2 diabetes (T2DM). Hyperglycemia represents the main mechanism in the pathogenesis of DR leading eventually to endothelial dysfunction. vWF is a marker of endothelial dysfunction, but its relation to DR is not yet well-established.

Methods

The present study included 60 patients with T2DM divided into three equal groups according to the presence and the stage of retinopathy. Each patient was subjected to full history taking, physical examination including fundus examination, and laboratory investigations including glycemic and lipid profile, urinary albumin to creatinine ratio (UACR), and plasma vWF level.

Results

Plasma vWF was significantly higher in patients with DR than in patients without retinopathy. vWF was positively correlated to age, HbA1c, diabetes duration, and UACR in DR groups and the total sample. Univariate regression analysis revealed that HbA1c, vWF, BMI, diabetes duration, and UACR were independent risk factors for DR, while multivariate regression analysis showed none of them to be an independent risk factor for DR. A vWF cut-off value of > 180 could differentiate patients with DR from patients without DR with a sensitivity of 97.5%, specificity of 75%, and AUC 0.937*.

Conclusions

vWF level is higher in patients with DR reflecting the role of endothelial dysfunction in the development of DR. Moreover, it is one of the risk factors affecting DR in univariate but not in multivariate analysis. A cut-off value of vWF level was set to differentiate between patients with and without DR.

Pathogenic role of human C-reactive protein in diabetic retinopathy

PURPOSE

Elevated blood levels of C-reactive protein (CRP) are associated with both type 1 and type 2 diabetes and diabetic complications, such as diabetic retinopathy (DR). However, its pathogenic role in DR remains unknown. The present study aims to investigate the potential role of CRP in DR pathogenesis and explore its underlying mechanism.

MATERIALS AND METHODS

Human CRP transgenic (hCRP-Tg) rats were employed for streptozotocin (STZ)-induced diabetic and oxygen-induced retinopathy (OIR) models. The retina function was monitored by electroretinography (ERG) and retinal thickness was measured by optical coherence tomography (OCT). TUNEL and cell death ELISA were performed to measure the apoptosis. Oxidative stress was detected by the measurement of reactive oxygen species (ROS) in cells and 3-Nitrotyrosine staining in tissue sections.

RESULTS

In non-diabetic condition, hCRP-Tg with elevated hCRP levels in the retinas demonstrated declined ERG responses and decreased retinal thickness. In STZ-induced diabetic condition, overexpression of hCRP deteriorated retinal neurodegeneration as shown by ERG and apoptosis assays. hCRP also exacerbated retinal leukostasis and acellular capillary formation induced by diabetes. In the OIR model, overexpression of hCRP exacerbated retinal neovascularization (NV). In retinal cell lines, hCRP treatment induced cell death and over-production of ROS. Furthermore, hCRP-induced overexpression of pro-inflammatory, pro-oxidative, and pro-angiogenic factors was associated with up-regulation of CD32 and the NF-κB signaling in the retinas.

CONCLUSIONS

Elevated hCRP levels play a pathogenic role in DR. Targeting the hCRP-CD32-NF-κB pathway may represent a novel therapeutic strategy for DR.

Relationship between Proliferative Diabetic Retinopathy and Inflammatory Markers in Patients with Type 1 Diabetes in Brazil: A Nested Case Control Study

INTRODUCTION

This study examined the relationship between proliferative diabetic retinopathy (PDR) and serum levels of C-reactive protein, VEGF, TNF-α, and IL-6 inflammatory biomarkers, related to the pathophysiology of diabetic retinopathy.

METHODS

This cross-sectional, case control study comprised 240 patients with type 1 diabetes (80 cases with PDR and 160 controls without diabetic retinopathy) who were matched for gender and duration of diabetes.

RESULTS

C-reactive protein was the only inflammatory biomarker that was positively related to PDR (OR 1.96; 95% CI 1.01-3.78, p = 0.0045). We also noted an association between high glycated hemoglobin levels, the use of angiotensin-converting enzyme inhibitor, low glomerular filtration rate, and PDR.

CONCLUSION

Patients with higher levels of C-reactive protein are more likely to present with PDR. We did not find a link between serum levels of VEGF, TNF-α, or IL-6 and PDR. The function of inflammatory biomarkers in PDR must be addressed in further studies.

New Insights Into Immunological Therapy for Retinal Disorders

In the twentieth century, a conspicuous lack of effective treatment strategies existed for managing several retinal disorders, including age-related macular degeneration; diabetic retinopathy (DR); retinopathy of prematurity (ROP); retinitis pigmentosa (RP); uveitis, including Behçet's disease; and vitreoretinal lymphoma (VRL). However, in the first decade of this century, advances in biomedicine have provided new treatment strategies in the field of ophthalmology, particularly biologics that target vascular endothelial growth factor or tumor necrosis factor (TNF)-α. Furthermore, clinical trials on gene therapy specifically for patients with autosomal recessive or X-linked RP have commenced. The overall survival rates of patients with VRL have improved, owing to earlier diagnoses and better treatment strategies. However, some unresolved problems remain such as primary or secondary non-response to biologics or chemotherapy, and the lack of adequate strategies for treating most RP patients. In this review, we provide an overview of the immunological mechanisms of the eye under normal conditions and in several retinal disorders, including uveitis, DR, ROP, RP, and VRL. In addition, we discuss recent studies that describe the inflammatory responses that occur during the course of these retinal disorders to provide new insights into their diagnosis and treatment.

Systemic inflammation and eye diseases. The Beijing Eye Study

Purpose

Systemic inflammation is potentially associated with ocular diseases such as late age-related macular degeneration (AMD). Using the serum concentration of high-sensitive C-reactive protein (hs-CRP) as surrogate of systemic inflammation, we examined potential associations between the serum hs-CRP concentration and the presence and degree of eye diseases.

Methods

The population-based Beijing Eye Study included 3468 Chinese individuals. The study participants underwent a standardized interview and a detailed ophthalmic examination. The serum concentration of hs-CRP was determined.

Results

Out of 3468 participants, 2452 (70.7%) individuals (mean age:63.4±9.4 year; range:50–91 years) had hs-CRP measurements (mean:1.96±4.07mg/L). In multivariate analysis, higher serum concentration of hs-CRP was significantly (regression coefficient r: 0.21) associated with a higher level of diabetic retinopathy (P = 0.007; standardized regression coefficient beta:0.06; non-standardized regression coefficient B:1.35; 95% confidence interval (CI):0.37,2.22) and polypoidal choroidal vasculopathy (P = 0.002;beta:0.06;B:6.22;95%CI:2.24,10.2) after adjusting for higher serum concentration of high-density lipoproteins (P<0.001;beta:-0.12;B:-1.31;95%CI:-1.77,-0.85), higher body mass index (P = 0.01;beta:0.06;B:0.06;95%CI:0.01, 0.11), lower level of education (P = 0.04;beta:-0.06;B:-0.22;95%CI:-0.42,-0.02), lower cognitive function score (P = 0.01;beta:-0.07;B:-0.08;95%CI:-0.13,-0.02). If the presences of other ocular diseases were added to the model, the presence of glaucoma (P = 0.99), open-angle glaucoma (P = 0.80), angle-closure glaucoma (P = 0.67), pseudoexfoliation (P = 0.18), nuclear cataract (P = 0.30), cortical cataract (P = 0.15), subcapsular cataract (P = 0.59), retinal vein occlusions (P = 0.33), central serous choroidopathy (P = 0.44), early stage of age-related macular degeneration (AMD) (P = 0.46), intermediate stage of AMD (P = 0.20) and late stage of AMD (P = 0.91) including geographic atrophy (P = 0.60) or neovascular AMD (P = 0.68) were not significantly associated with the serum concentration of hs-CRP.

Conclusions

In Chinese aged 50+ years, higher serum concentration of hs-CRP was significantly associated with a higher level of diabetic retinopathy and higher frequency of polypoidal choroidal vasculopathy. Other major ocular disorders, namely glaucoma including open-angle glaucoma and angle-closure glaucoma, pseudoexfoliation, nuclear, cortical or subcapsular cataract, retinal vein occlusions, central serous choroidopathy, early, intermediate or late stage of AMD including geographic atrophy, were not significantly associated with hs-CRP serum concentrations. It suggests that these diseases, in contrast to diabetic retinopathy and polypoidal choroidal vasculopathy, were not associated with a major systemic inflammatory component.

C-Reactive protein and progression of vision loss in retinitis pigmentosa

PURPOSE

Chronic inflammation is involved in retinitis pigmentosa (RP). We demonstrated previously that intraocular inflammatory levels, as measured by slit-lamp ophthalmoscopy or laser flare photometry, are inversely correlated with central visual function in patients with RP. Here, we investigated the relationship between serum high-sensitivity C-reactive protein (hs-CRP) and visual parameters in RP.

METHODS

We studied 58 consecutive typical patients with RP <40 years old and 29 age- and gender-matched controls. High-sensitivity C-reactive protein (hs-CRP) was detected by immunoturbidimetry. The relationships between hs-CRP and visual parameters including best-corrected visual acuity (BCVA), mean deviation (MD) of static perimetry tests (Humphrey Field Analyzer, the central 10-2 programme) and VA changes over the prior 5 years and MD changes over the prior 3 years were analysed in the patients with RP.

RESULTS

The serum hs-CRP levels of the patients with RP were significantly higher than those of the controls (0.06 ± 0.08 versus 0.03 ± 0.04 mg/dl, p = 0.0119). In the patients with RP, there was no correlation of hs-CRP with cross-sectionally assessed VA or MD, but the baseline hs-CRP was significantly correlated with the MD deterioration (r = -0.4073, p = 0.0314).

CONCLUSION

The average serum hs-CRP was significantly increased in the patients with RP, and higher hs-CRP was associated with faster deterioration of central visual function. These results suggest that the systemic inflammatory profile is altered and may be associated with disease progression in RP.

Associations Between Inflammatory Markers, Hemostatic Markers, and Microvascular Complications in 182 Chinese Patients With Type 2 Diabetes Mellitus

OBJECTIVE

To examine the associations between inflammatory markers, coagulation and fibrinolysis parameters, and microvascular complications in 182 Chinese patients with type 2 diabetes mellitus (T2DM) who sought treatment at a large hospital in Zhejiang province, China.

METHODS

We investigated the relationships of blood inflammatory markers with hemostatic markers in 87 patients with T2DM who did not have complications and 95 patients with T2DM who had microvascular complications.

RESULTS

C-reactive protein (CRP) and interleukin-6 (IL-6) were significantly correlated with fibrinogen, thrombin-antithrombin III complex (TAT III), plasminogen activator inhibitor-1 (PAI-1), von Willebrand factor (vWF), and coagulation factors (F) VII in patients with T2DM who had microvascular complications (P <.05). Based on logistic regression analysis, the highest-tertile groups of fibrinogen, FVII, and FVIII, corresponded to a greater risk of high CRP, whereas risk of high IL-6 was significantly greater in the groups with highest-tertile values for fibrinogen, FVII, TAT III, PAI-1, and activated protein C (APC).

CONCLUSIONS

Elevated levels of CRP and IL-6 might be associated with increased coagulability and a tendency towards thrombus formation in patients with T2DM who have microvascular complications.

Circulating Biomarkers of Diabetic Retinopathy: An Overview Based on Physiopathology

Diabetic retinopathy (DR) is the main cause of working-age adult-onset blindness. The currently available treatments for DR are applicable only at advanced stages of the disease and are associated with significant adverse effects. In early stages of DR the only therapeutic strategy that physicians can offer is a tight control of the risk factors for DR. Therefore, new pharmacological treatments for these early stages of the disease are required. In order to develop therapeutic strategies for early stages of DR new diagnostic tools are urgently needed. In this regard, circulating biomarkers could be useful to detect early disease, to identify those diabetic patients most prone to progressive worsening who ought to be followed up more often and who could obtain the most benefit from these therapies, and to monitor the effectiveness of new drugs for DR before more advanced DR stages have been reached. Research of biomarkers for DR has been mainly based on the pathogenic mechanism involved in the development of DR (i.e., AGEs, oxidative stress, endothelial dysfunction, inflammation, and proangiogenic factors). This review focuses on circulating biomarkers at both early and advanced stages that could be relevant for the prediction or detection of DR.

Association between Von Willebrand factor, disintegrin and metalloproteinase with thrombospondin type 1 motif member 13, d-Dimer and cystatin C levels with retinopathy in type 1 diabetes mellitus

BACKGROUND

We evaluated the association between plasma levels of VWF, ADAMTS13 and d-Dimer, which consist on endothelial dysfunction and hypercoagulability biomarkers, and cystatin C with retinopathy in type 1 diabetic patients.

METHODS

Patients were classified according to presence (n=55) or absence (n=70) of retinopathy. Plasma levels of VWF, ADAMTS13, d-Dimer and cystatin C were evaluated by ELISA and ADAMTS13 activity was evaluated by FRET.

RESULTS

Plasma levels of VWF (p=0.033), ADAMTS13 activity (p=0.014), d-Dimer (p=0.002) and cystatin C (p<0.001) were elevated in diabetic patients with retinopathy compared to those without this complication. The multivariate logistic regression analysis showed that ADAMTS13 activity (p=0.031) d-Dimer (p=0.015) and cystatin C (p=0.001) remained associated with retinopathy after adjustment for age, diabetes duration, use of statin, use of ACEi or angiotensin antagonist, use of acetylsalicylic acid and glomerular filtration rate.

CONCLUSION

ADAMTS13 activity, d-Dimer and cystatin C are associated with retinopathy in type 1 diabetic patients and are promising biomarkers for the diagnosis and monitoring of diabetic retinopathy.

P-selectin Plasma Levels and Genetic Variant Associated With Diabetic Retinopathy in African Americans

PURPOSE

To report the prevalence and risk factors for retinopathy in African Americans with impaired fasting glucose (IFG) and type 2 diabetes in the Jackson Heart Study and to determine if P-selectin plasma levels are independently associated with retinopathy in this population.

DESIGN

Prospective, cross-sectional observational study.

METHODS

setting: Community-based epidemiologic study.

STUDY POPULATION

Total of 629 patients with type 2 diabetes and 266 participants with impaired fasting glucose.

OBSERVATION PROCEDURES

Bilateral, 7-field fundus photographs were scored by masked readers for diabetic retinopathy (DR) level. Covariate data including P-selectin plasma levels and genotypes were collected in a standardized fashion.

MAIN OUTCOME MEASURES

Association between risk factors, including P-selectin plasma levels and genotypes, and retinopathy.

RESULTS

The prevalences of any retinopathy among participants with IFG and type 2 diabetes were 9.4% and 32.4%, respectively. Among those with type 2 diabetes, in multivariate models adjusted for age, sex, and other traditional risk factors, higher P-selectin levels were associated with any DR (odds ratio = 1.11, 95% confidence interval = 1.02-1.21, P = .02) and proliferative DR (odds ratio = 1.23, 95% confidence interval = 1.03-1.46, P = .02). To further investigate the relationship between P-selectin and DR, we examined the association between P-selectin genotype and DR. Minor allele homozygotes for the variant rs6128 were less likely to develop DR (P after Bonferroni correction = 0.03).

CONCLUSIONS

Both serologic and genetic data show an association between P-selectin and DR in the Jackson Heart Study. If confirmed in other studies, this association may provide insight into the pathogenesis of retinopathy.

Phenotypes and biomarkers of diabetic retinopathy

Diabetic retinopathy (DR) remains a major cause of blindness as the prevalence of diabetes is expected to approximately double globally between 2000 and 2030. DR progresses over time at different rates in different individuals with only a limited number developing significant vision loss due to the two major vision-threatening complications, clinically significant macular edema and proliferative retinopathy. Good metabolic control is important to prevent and delay progression, but whereas some patients escape vision loss even with poor control, others develop vision loss despite good metabolic control. Our research group has been able to identify three different DR phenotypes characterized by different dominant retinal alterations and different risks of progression to vision-threatening complications. Microaneurysm turnover has been validated as a prognostic biomarker of development of clinically significant macular edema, whereas subclinical macular edema identified by OCT and mfERG appear to be also good candidates as organ-specific biomarkers of DR. Hemoglobin A1c remains the only confirmed systemic prognostic biomarker of DR progression. The availability of biomarkers of DR progression and the identification of different phenotypes of DR with different risks for development of vision-threatening complications offers new perspectives for understanding DR and for its personalized management.

Current trends in the monitoring and treatment of diabetic retinopathy in young adults

The diagnosis and treatment of diabetic retinopathy (DR) in young adults have significantly improved in recent years. Research methods have widened significantly, for example, by introducing spectral optical tomography of the eye. Invasive diagnostics, for example, fluorescein angiography, are done less frequently. The early introduction of an insulin pump to improve the administration of insulin is likely to delay the development of diabetic retinopathy, which is particularly important for young patients with type 1 diabetes mellitus (T1DM). The first years of diabetes occurring during childhood and youth are the most appropriate to introduce proper therapeutic intervention before any irreversible changes in the eyes appear. The treatment of DR includes increased metabolic control, laserotherapy, pharmacological treatment (antiangiogenic and anti-inflammatory treatment, enzymatic vitreolysis, and intravitreal injections), and surgery. This paper summarizes the up-to-date developments in the diagnostics and treatment of DR. In the literature search, authors used online databases, PubMed, and clinitrials.gov and browsed through individual ophthalmology journals, books, and leading pharmaceutical company websites.

Evaluation of corneal endothelium in children and adolescents with type 1 diabetes mellitus

Purpose. To evaluate the systemic and local factors that contribute to the damage of endothelial cells in diabetic patients and to compare the endothelial structure of the cornea in diabetic and nondiabetic patients. Materials and Methods. The endothelial cell density (ECD) and central corneal thickness (CCT) were investigated in 123 eyes of type 1 diabetic patients and in 124 eyes of nondiabetic patients. The mean diabetic patients age was 15.34 ± 3.06 years versus 14.58 ± 2.01 years in the control group. The mean duration of diabetes was 8.02 ± 3.9 years. The corneal endothelium was imaged by the Topcon SP-2000P. Results. The mean ECD in diabetic eyes was 2435.55 ± 443.43 cells/mm² and was significantly lower than in control group (2970.75 ± 270.1 cells/mm²). The mean CCT was 0.55 ± 0.03 mm in diabetic group versus 0.53 ± 0.033 mm in control group. ECD and CCT significantly correlated only with duration of diabetes. There was no correlation between ECD and CCT and patient age, sex, HbA1C level, and plasma creatinine level. Conclusions. ECD is decreased and CCT is increased in children and adolescents with diabetes mellitus. Duration of diabetes is the factor that affects ECD and CCT.

Neutrophil-to-lymphocyte ratio as a quick and reliable predictive marker to diagnose the severity of diabetic retinopathy

INTRODUCTION

Diabetic retinopathy (DR) is the most common complication and cause of visual impairment in diabetes patients. The pathogenesis is not fully understood, but several studies have suggested that inflammation plays an important role. The neutrophil-to-lymphocyte ratio (NLR) was defined as a novel potential marker to determine inflammation. We aimed to evaluate the relationship between DR and inflammation by using NLR.

PATIENTS AND METHODS

The study was included 58 patients diagnosed with type 2 diabetes mellitus. Twenty-four of them had DR. The control group was composed of 52 age- and sex-matched healthy subjects. Retinopathy was graded using the International Clinical Diabetic Retinopathy Disease Severity Scale.

RESULTS

NLR values of the diabetes patients were significantly higher than those of the healthy control group (P<0.001), and NLR levels of the patients with DR were higher than those of the patients without DR (P<0.001). In addition, NLR values were correlated with the presence of DR and DR grades (r=0.466, P<0.001; and r=0.630, P<0.001, respectively).

CONCLUSIONS

According to our knowledge, this is the first study investigating the relationship between NLR, which is an inflammatory marker, and DR and its severity. Our results suggest that while evaluating diabetes patients in terms of DR, higher NLR values may be a remarkable marker.