Diabetic Eye Disease

Diabetic Eye Disease Publications

Ung C, Sanchez AV, Shen L, Davoudi S, Ahmadi T, Navarro-Gomez D, Chen CJ, Hancock H, Penman A, Hoadley S, Consugar M, Restrepo C, Shah VA, Arboleda-Velasquez JF, Sobrin L, Gai X, Kim LA. Whole Exome Sequencing Identification of Novel Candidate Genes in Patients with Proliferative Diabetic Retinopathy. Vision Res 2017;Abstract

Rare or novel gene variants in patients with proliferative diabetic retinopathy may contribute to disease development. We performed whole exome sequencing (WES) on patients at the phenotypic extremes of diabetic retinal complications: 57 patients diagnosed with proliferativediabetic retinopathy (PDR) as cases and 13 patients with no diabetic retinopathy despite at least 10 years of type 2 diabetes as controls. Thirty-one out of the 57 cases and all 13 controls were from the African American Proliferative Diabetic Retinopathy Study (AA). The rest of the cases were of mixed ethnicities (ME). WES identified 721 candidate genes with rare or novel non-synonymous variants found in at least one case with PDR and not present in any controls. After filtering for genes with null alleles in greater than two cases, 28 candidate genes were identified in our ME cases and 16 genes were identified in our AA cases. Our analysis showed rare and novel variants within these genes that could contribute to the development of PDR, including rare non-synonymous variants in FAM132A, SLC5A9, ZNF600, and TMEM217. We also identified previously unidentified variants in VEGFB and APOB. We found that VEGFB, VPS 13B, PHF21A, NAT1, ZNF600, PKHD1L1 expression was reduced in HRECs under high glucose conditions. In an exome sequence analysis of patients with PDR, we identified variants in genes that could contribute to pathogenesis. Seven of these genes were further validated and found to have reduced expression in human retinal endothelial cells under high glucose conditions, suggestive of an important role in the development of PDR.

Chen Q, Qiu F, Zhou K, Matlock GH, Takahashi Y, Rajala RVS, Yang Y, Moran E, Ma J-X. Pathogenic Role of MicroRNA-21 in Diabetic Retinopathy Through Down-Regulation of PPARα. Diabetes 2017;Abstract

Fenofibrate, a specific agonist of peroxisome proliferator-activated receptor alpha (PPARα), displays robust therapeutic effects on diabetic retinopathy (DR) in type 2 diabetic patients. Our recent studies have shown that PPARα is down-regulated in the diabetic retina, which contributes to the pathogenesis of DR. However, the mechanism for diabetes-induced down-regulation of PPARα remains unknown. We investigated the role of microRNA-21 (miR-21) in regulating PPARα in DR. MiR-21 was over-expressed, while PPARα levels were decreased in the retina of db/db mice, a type 2 diabetic model. Such alterations were also observed in palmitate-treated retinal endothelial cells. MiR-21 targeted PPARα by inhibiting its mRNA translation. Knockout of miR-21 prevented the decrease of PPARα, alleviated microvascular damage, ameliorated inflammation and reduced cell apoptosis in the retina of db/db mice. Intravitreal injection of miR-21 inhibitor attenuated PPARα down-regulation and ameliorated retinal inflammation in db/db mice. Further, retinal miR-21 levels were increased, while PPARα levels were decreased in oxygen-induced retinopathy (OIR). Knockout of miR-21 prevented PPARα down-regulation and ameliorated retinal neovascularization and inflammation in OIR retinas. In conclusion, diabetes-induced over-expression of miR-21 in the retina is responsible, at least in part, for PPARα down-regulation in DR. Targeting miR-21 may represent a novel therapeutic strategy for DR.

Laíns I, Talcott KE, Santos AR, Marques JH, Gil P, Gil J, Figueira J, Husain D, Kim IK, Miller JW, Silva R, Miller JB. CHOROIDAL THICKNESS IN DIABETIC RETINOPATHY ASSESSED WITH SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY. Retina 2017;Abstract

PURPOSE: To compare the choroidal thickness (CT) of diabetic eyes (different stages of disease) with controls, using swept-source optical coherence tomography. METHODS: A multicenter, prospective, cross-sectional study of diabetic and nondiabetic subjects using swept-source optical coherence tomography imaging. Choroidal thickness maps, according to the nine Early Treatment Diabetic Retinopathy Study (ETDRS) subfields, were obtained using automated software. Mean CT was calculated as the mean value within the ETDRS grid, and central CT as the mean in the central 1 mm. Diabetic eyes were divided into four groups: no diabetic retinopathy (No DR), nonproliferative DR (NPDR), NPDR with diabetic macular edema (NPDR + DME), and proliferative DR (PDR). Multilevel mixed linear models were performed for analyses. RESULTS: The authors included 50 control and 160 diabetic eyes (n = 27 No DR, n = 51 NPDR, n = 61 NPDR + DME, and n = 21 PDR). Mean CT (ß = -42.9, P = 0.022) and central CT (ß = -50.2, P = 0.013) were statistically significantly thinner in PDR eyes compared with controls, even after adjusting for confounding factors. Controlling for age, DR eyes presented a significantly decreased central CT than diabetic eyes without retinopathy (β = -36.2, P = 0.009). CONCLUSION: Swept-source optical coherence tomography demonstrates a significant reduction of CT in PDR compared with controls. In the foveal region, the choroid appears to be thinner in DR eyes than in diabetic eyes without retinopathy.

Dagher Z, Gerhardinger C, Vaz J, Goodridge M, Tecilazich F, Lorenzi M. The Increased Transforming Growth Factor-β Signaling Induced by Diabetes Protects Retinal Vessels. Am J Pathol 2017;187(3):627-638.Abstract

The roles of transforming growth factor (TGF)-β in extracellular matrix production and vascular remodeling, coupled with increased TGF-β expression and signaling in diabetes, suggest TGF-β as an important contributor to the microangiopathy of diabetic retinopathy and nephropathy. To investigate whether increased TGF-β signaling could be a therapeutic target for preventing retinopathy, we used a pharmacologic approach (SM16, a selective inhibitor of the type 1 TGF-β receptor activin receptor-like kinase 5, orally active) to inhibit the increased, but not the basal, Tgf-β signaling in retinal vessels of diabetic rats. At the level of vascular gene expression, 3.5 months' diabetes induced minimal changes. Diabetes + SM16 for 3 weeks caused widespread changes in gene expression poised to enhance vascular inflammation, thrombosis, leakage, and wall instability; these changes were not observed in control rats given SM16. The synergy of diabetes and SM16 in altering gene expression was not observed in the lung. At the level of vascular network morphology, 7 months' diabetes induced no detectable changes. Diabetes + SM16 for 3 weeks caused instead distorted morphology and decreased density. Thus, in diabetes, retinal vessels become dependent on a small increase in TGF-β signaling via activin receptor-like kinase 5 to maintain early integrity. The increased TGF-β signaling may protect against rapid retinopathy progression and should not be a target of inhibitory interventions.

Barham R, Rami HE, Sun JK, Silva PS. Evidence-Based Treatment of Diabetic Macular Edema. Semin Ophthalmol 2017;32(1):56-66.Abstract

Diabetes mellitus is a chronic disease that affects 415 million people worldwide. Despite treatment advances, diabetic eye disease remains a leading cause of vision loss worldwide. Diabetic macular edema (DME) is a common cause of vision loss in diabetic patients. The pathophysiology is complex and involves multiple pathways that ultimately lead to central retinal thickening and, if untreated, visual loss. First-line treatment of DME has evolved from focal/grid laser established by the Early Treatment of Diabetic Retinopathy Study (ETDRS) to intravitreous pharmacologic therapy. Landmark prospective clinical trials examining the effect of intravitreous injections of vascular endothelial growth factor (VEGF) inhibitors in the treatment of DME have demonstrated improved visual outcomes over focal grid laser. This review focuses on the scientific evidence treatment of DME, disease pathophysiology, clinical disease course, current treatment standards, and emerging novel therapeutic approaches.

Rami HE, Barham R, Sun JK, Silva PS. Evidence-Based Treatment of Diabetic Retinopathy. Semin Ophthalmol 2017;32(1):67-74.Abstract

Diabetic retinopathy (DR) is the most frequent microvascular complication from diabetes and requires annual screening and at least annual follow-up. A systemic approach to optimize blood glucose and blood pressure may halt progression to severe stages of DR and obviate the need for ocular treatment. Although there is evidence of benefit from fenofibrate or intravitreous antiVEGF treatment for eyes with nonproliferative DR (NPDR), these therapies are not standard care for NPDR at this time. Some patients with severe NPDR, especially those with type 2 diabetes, benefit from early panretinal photocoagulation (PRP). Once DR progresses to proliferative DR (PDR), treatment is often necessary to prevent visual loss. PRP remains mainstay treatment for PDR with high-risk characteristics. However, intravitreous antiVEGF injections appear to be a safe and effective treatment alternative for PDR through at least two years. Vitreoretinal surgery is indicated for PDR cases with non-clearing vitreous hemorrhage and/or tractional retinal detachment.

Gupta A, Cavallerano J, Sun JK, Silva PS. Evidence for Telemedicine for Diabetic Retinal Disease. Semin Ophthalmol 2017;32(1):22-28.Abstract

According to current projections, the number of Americans with diabetes mellitus will increase from 27.8 million in 2007 to 60.7 million in 2030. With the increasing gap between demand for eye care and supply of ophthalmologists and optometrists, and the non-uniform distribution of eye care providers in US counties, barriers to eye examinations will likely increase. Telemedicine assessment of diabetic retinal disease through remote retinal imaging and diagnosis has the potential to meet these growing demands. To establish evidence for a telemedicine program as an effective modality for diabetic retinopathy (DR) assessment, the interpretation of teleretinal images should compare favorably with Early Treatment Diabetic Retinopathy Study film or digital photographs. We review the current evidence on the critical features and characteristics of ocular telehealth programs for DR in the following categories: image gradability, mydriasis, sensitivity and specificity, cost-effectiveness, long-term effectiveness, patient comfort and satisfaction, and improvement of patient related outcomes.

Papavasileiou E, Davoudi S, Roohipoor R, Cho H, Kudrimoti S, Hancock H, Wilson JG, Andreoli C, Husain D, James M, Penman A, Chen CJ, Sobrin L. Association of serum lipid levels with retinal hard exudate area in African Americans with type 2 diabetes. Graefes Arch Clin Exp Ophthalmol 2017;255(3):509-517.Abstract
PURPOSE: Previous studies have yielded conflicting results regarding whether serum lipid levels are associated with retinal hard exudates in diabetic retinopathy. The majority of studies have assessed hard exudates only as a dichotomous trait (presence vs. absence) and included limited numbers of African Americans (AA). The purpose of this study was to determine if there are any associations between serum lipid levels and hard exudates in AA with type 2 diabetes (T2D). METHODS: 890 AA participants with T2D were enrolled from 5 sites. Macular fundus photographs were graded by masked ophthalmologist investigators. Hard exudate areas were measured using a semi-automated algorithm and ImageJ software. Multivariate regression models were used to determine the association between serum lipid levels and (1) presence of hard exudate and (2) area of hard exudate. RESULTS: Presence of hard exudates was associated with higher total cholesterol [(odds ratio (OR) = 1.08, 95 % confidence interval (CI) 1.03-1.13, P = 0.001)] and higher low-density lipoprotein (LDL) cholesterol (OR = 1.08, 95 % CI 1.03-1.14, P = 0.005) in models controlling for other risk factors. Hard exudate area was also associated with both higher total and LDL cholesterol levels (P = 0.04 and 0.01, respectively) in multivariate models controlling for other risk factors. CONCLUSIONS: Higher total and LDL cholesterol were associated with the presence of hard exudates and a greater hard exudate area in AA with T2D. This information can be used to counsel diabetic patients regarding the importance of lipid control to decrease the risk of macular hard exudates.
Jee D, Keum N, Kang S, Arroyo JG. Sleep and diabetic retinopathy. Acta Ophthalmol 2017;95(1):41-47.Abstract

PURPOSE: To investigate the association between sleep duration and diabetic retinopathy (DR). METHODS: A population-based cross-sectional study using a nation-wide, systemically stratified, multistage, clustered sampling method included a total of 1670 subjects aged ≥40 years with diabetes who participated in the Korean National Health and Nutrition Examination Survey during 2008-2012. All participants performed standardized interviews, including self-reported sleep duration, and comprehensive ophthalmic examinations. Seven standard retinal fundus photographs were obtained from both eyes after pupil dilatation. Diabetic retinopathy (DR) was graded and classified as any DR and vision-threatening DR. Participants were stratified into men and women. RESULTS: The mean sleep duration was 6.71 hr/day. In men, adjusted OR of any DR was 1.88 [95% confidence interval (OR), 1.01-3.59] in those with ≤5 hr sleep, and 2.19 (95% CI, 1.01-4.89) in those with ≥9 hr sleep, compared to in subjects with 6-8 hr sleep, after adjusting for potential confounders including age, body mass index (BMI), diabetes duration, fasting glucose level, haemoglobin A1c levels and hypertension. In women, however, no significant association between sleep duration and DR was found. The vision-threatening DR was not significantly associated with sleep duration in either men or women. CONCLUSIONS: Short and long sleep was associated with high prevalence of DR in men. Sleep deprivation may be involved in the pathogenesis of DR development.

Lammer J, Prager SG, Cheney MC, Ahmed A, Radwan SH, Burns SA, Silva PS, Sun JK. Cone Photoreceptor Irregularity on Adaptive Optics Scanning Laser Ophthalmoscopy Correlates With Severity of Diabetic Retinopathy and Macular Edema. Invest Ophthalmol Vis Sci 2016;57(15):6624-6632.Abstract

Purpose: To determine whether cone density, spacing, or regularity in eyes with and without diabetes (DM) as assessed by high-resolution adaptive optics scanning laser ophthalmoscopy (AOSLO) correlates with presence of diabetes, diabetic retinopathy (DR) severity, or presence of diabetic macular edema (DME). Methods: Participants with type 1 or 2 DM and healthy controls underwent AOSLO imaging of four macular regions. Cone assessment was performed by independent graders for cone density, packing factor (PF), nearest neighbor distance (NND), and Voronoi tile area (VTA). Regularity indices (mean/SD) of NND (RI-NND) and VTA (RI-VTA) were calculated. Results: Fifty-three eyes (53 subjects) were assessed. Mean ± SD age was 44 ± 12 years; 81% had DM (duration: 22 ± 13 years; glycated hemoglobin [HbA1c]: 8.0 ± 1.7%; DM type 1: 72%). No significant relationship was found between DM, HbA1c, or DR severity and cone density or spacing parameters. However, decreased regularity of cone arrangement in the macular quadrants was correlated with presence of DM (RI-NND: P = 0.04; RI-VTA: P = 0.04), increasing DR severity (RI-NND: P = 0.04), and presence of DME (RI-VTA: P = 0.04). Eyes with DME were associated with decreased density (P = 0.04), PF (P = 0.03), and RI-VTA (0.04). Conclusions: Although absolute cone density and spacing don't appear to change substantially in DM, decreased regularity of the cone arrangement is consistently associated with the presence of DM, increasing DR severity, and DME. Future AOSLO evaluation of cone regularity is warranted to determine whether these changes are correlated with, or predict, anatomic or functional deficits in patients with DM.

Horton MB, Silva PS, Cavallerano JD, Aiello LP. Clinical Components of Telemedicine Programs for Diabetic Retinopathy. Curr Diab Rep 2016;16(12):129.Abstract

Diabetic retinopathy is a leading cause of new-onset vision loss worldwide. Treatments supported by large clinical trials are effective in preserving vision, but many persons do not receive timely diagnosis and treatment of diabetic retinopathy, which is typically asymptomatic when most treatable. Telemedicine evaluation to identify diabetic retinopathy has the potential to improve access to care, but there are no universal standards regarding camera choice or protocol for ocular telemedicine. We review the literature regarding the impact of imaging device, number and size of retinal images, pupil dilation, type of image grader, and diagnostic accuracy on telemedicine assessment for diabetic retinopathy. Telemedicine assessment of diabetic retinopathy has the potential to preserve vision, but further development of telemedicine specific technology and standardization of operations are needed to better realize its potential.

Song BJ, Aiello LP, Pasquale LR. Presence and Risk Factors for Glaucoma in Patients with Diabetes. Curr Diab Rep 2016;16(12):124.Abstract

Diabetes mellitus represents a growing international public health issue with a near quadrupling in its worldwide prevalence since 1980. Though it has many known microvascular complications, vision loss from diabetic retinopathy is one of the most devastating for affected individuals. In addition, there is increasing evidence to suggest that diabetic patients have a greater risk for glaucoma as well. Though the pathophysiology of glaucoma is not completely understood, both diabetes and glaucoma appear to share some common risk factors and pathophysiologic similarities with studies also reporting that the presence of diabetes and elevated fasting glucose levels are associated with elevated intraocular pressure-the primary risk factor for glaucomatous optic neuropathy. While no study has completely addressed the possibility of detection bias, most recent epidemiologic evidence suggests that diabetic populations are likely enriched with glaucoma patients. As the association between diabetes and glaucoma becomes better defined, routine evaluation for glaucoma in diabetic patients, particularly in the telemedicine setting, may become a reasonable consideration to reduce the risk of vision loss in these patients.

Horton MB, Silva PS, Cavallerano JD, Aiello LP. Operational Components of Telemedicine Programs for Diabetic Retinopathy. Curr Diab Rep 2016;16(12):128.Abstract

Diabetic retinopathy is a leading cause of new-onset vision loss worldwide. Treatments supported by large clinical trials are effective in preserving vision, but many persons do not receive timely diagnosis and treatment of diabetic retinopathy, which is typically asymptomatic when most treatable. Telemedicine evaluation to identify diabetic retinopathy has the potential to improve access to care and improve outcomes, but incomplete implementation of published standards creates a risk to program utility and sustainability. In a prior article, we reviewed the literature regarding the impact of imaging device, number and size of retinal images, pupil dilation, type of image grader, and diagnostic accuracy on telemedicine assessment for diabetic retinopathy. This article reviews the literature regarding the impact of automated image grading, cost effectiveness, program standards, and quality assurance (QA) on telemedicine assessment of diabetic retinopathy. Telemedicine assessment of diabetic retinopathy has the potential to preserve vision, but greater attention to development and implementation of standards is needed to better realize its potential.