Similarities and differences in early retinal phenotypes in hypertension and diabetes

Establishing an objective quantitative method for assessing the severity of plus disease in retinopathy of prematurity

BACKGROUND

To establish an objective method for assessing plus disease severity in retinopathy of prematurity.

METHODS

Six images of plus diseases that were color-coded according to severity and published in the International Classification of Retinopathy of Prematurity, Third Edition (ICROP3) were analyzed. These images were individually processed, and the best-fit curve and vessel course in zone I were obtained using ImageJ software. Tortuosity indices (TIs) of the major vessels in the temporal quadrants were calculated. Data from real-world patients with no plus, pre-plus, and plus diseases were analyzed and compared with those of the ICROP.

RESULTS

The TIs of the arteries and veins, the sum of these TIs, and the artery/vein (A/V) TI ratios increased incrementally from grades 1 to 6. The trend revealed that the arterial tortuosity increased more than the venous tortuosity. The degree of venous tortuosity was similar from grades 3-5 but higher in grade 6. The A/V TI ratio increased in grades 1-3, stabilized in grades 3-5, and peaked in grade 6. Analysis of data from real-world patients showed increased TI of both arteries and veins, similar to the ICROP3. However, the A/V TI ratio did not show an increasing trend.

CONCLUSION

Objective methods for assessing disease severity can provide insights into the potential pathophysiological mechanisms of plus disease progression. Arterial tortuosity is more prominent than venous tortuosity. Venous features become more prominent as plus disease progresses, which may obscure the progression of arterial tortuosity.

Hypertension Likely Drives Arteriolar Wall Thickening in Preclinical Diabetic Retinopathy While Diabetes Drives Wall Thickness in Clinical Retinopathy

Purpose

Both hypertension and diabetes are known to increase the wall-to-lumen ratio (WLR) of retinal arterioles, but the differential effects are unknown. Here, we study the timing and relative impact of hypertension versus diabetes on the WLR in diabetic retinopathy (DR) to address this unresolved question.

Methods

This prospective cross-sectional study compared the retinal arteriolar WLR in 17 healthy eyes, 15 with diabetes but no apparent DR (DM no DR), and 8 with diabetic macular edema (DME) and either nonproliferative or proliferative DR. We imaged each arteriole using adaptive optics scanning laser ophthalmoscopy and measured the WLR using ImageJ. Multiple linear regression (MLR) was performed to estimate the effects of hypertension, diabetes, and age on the WLR.

Results

Both subjects with DM no DR and subjects with DME had significantly higher WLR than healthy subjects (0.36 ± 0.08 and 0.42 ± 0.08 vs. 0.29 ± 0.07, 1-way ANOVA P = 0.0009). MLR in healthy subjects and subjects with DM no DR showed hypertension had the strongest effect (regression coefficient = 0.08, P = 0.009), whereas age and diabetes were not significantly correlated with WLR. MLR in all three groups together (healthy, DM no DR, and DME) showed diabetes had the strongest effect (regression coefficient = 0.05, P = 0.02), whereas age and hypertension were not significantly correlated with WLR.

Conclusions

Hypertension may be an early driver of retinal arteriolar wall thickening in preclinical DR, independent of age or diabetes, whereas changes specific to DR may drive wall thickening in DME and later DR stages.

Translational Relevance

We offer a framework for understanding the relative contributions of hypertension and diabetes on the vascular wall, and emphasize the importance of hypertension control early in diabetes even before DR onset.

Diabetic Retinopathy during pregnancy in Hispanic women with latent Toxoplasma gondii infection

BACKGROUND

Retinal photography was performed in pregnancy and postpartum in pregnant Hispanic women with latent Toxoplasma gondii (TG) infection in order to screen for characteristic retinal lesions or the particular scars found in people with active T. gondii infection. A comparison group of TG negative women was included in the study but they did not have retinal photography.

OBJECTIVE

The goal of the parent study was to assess for adverse pregnancy events and evidence for parasite reactivation in TG positive (TG + ) women, through examination of the eyes for characteristic lesions. Retinal photography, usually at prenatal visits 2 (17 +/- 3.35 weeks) and 3 (26.3+/-1.75) weeks, was done on TG + women. Fifty-six of these women also (43 %) had retinal photography at the postpartum visit. Health and demographic data were obtained at the first prenatal visit for all women.

STUDY DESIGN

From the 690 recruited at the first prenatal visit, 128 TG- women and 158 TG + women were enrolled in a prospective study through pregnancy and the postpartum. All TG- women (n = 532) provided data at the first prenatal visit and throughout their pregnancy and birth through the EHR. This allowed comparison of health and outcome data for the TG + compared to a larger number of TG- Hispanic pregnant women.

RESULTS

While there was no evidence of ocular toxoplasmosis during pregnancy, there was a surprisingly large number (42 %) of TG + women with diabetic retinopathy (DR). We also observed that TG + women had a 20 % incidence of gestational diabetes mellitus (GDM) compared to 11.3 % in the TG- women (p = 0.01). At postpartum (mean 5.6 weeks), 23 of 30 women with pregnancy DR showed no DR in the postpartum.

CONCLUSIONS

No characteristic T. gondii lesions were discovered. Retinal photography serendipitously revealed DR in these T. gondii positive women. It was also found that latent TG infection was associated with increased incidence of GDM. Hispanic pregnant women's increased risk for latent TG infection, GDM and DR are underappreciated. Retinal photography may need to be considered an innovative approach to screening.

Alterations of outer retinal reflectivity in diabetic patients without clinically detectable retinopathy

PURPOSE

This study aimed to investigate alterations of outer retinal reflectivity on spectral-domain optical coherence tomography (OCT) in diabetic patients without clinically detectable retinopathy (NDR).

METHODS

In this retrospective study, 64 NDR patients and 71 controls were included. Relative reflectivity (RR) of the ellipsoid zone (EZ), photoreceptor outer segment (OS) and inner segment (IS), and outer nuclear layer (ONL) at the foveola and at 500 μm, 1000 μm, and 2000 μm nasal (N), temporal (T), superior (S), and inferior (I) to the foveola was measured by cross-line OCT and ImageJ. Retinal vessel densities (VD) in fovea, parafovea, and perifovea areas were detected by OCT angiography (OCTA).

RESULTS

EZ RR in most retinal locations was significantly lower in NDR eyes compared to controls (all P < 0.05), except the foveola. Compared with controls, NDR eyes also displayed lower RR at N2000, T2000, S1000, and I1000 of OS, at S500 and I500 of IS, and at I500 of ONL (all P < 0.05). Negative correlations could be observed between retinal RR and diabetes duration, HbA1c, and best-corrected visual acuity (BCVA) (r =  - 0.303 to - 0.452). Compared to controls, EZ, OS, and IS RR of the NDR eyes showed lower correlation coefficients with whole image SCP and DCP VD of parafovea and perifovea regions.

CONCLUSION

Outer retinal reflectivity, along with the coefficients between retinal reflectivity and VD, is reduced in NDR patients and is correlated with diabetes duration, HbA1c, and BCVA. The reduction of outer retinal reflectivity may be a potential biomarker of early retinal alterations in diabetic patients.

A Review on Diabetic Retinopathy

Diabetic retinopathy is a well-recognised microvascular complication of diabetes and is among the leading cause of blindness all over the world. Over the last decade, there have been advances in the diagnosis of diabetic retinopathy and diabetic macular edema. At the same time, newer therapies for the management of diabetic retinopathy have evolved. As a result of these advances, a decline in severe vision loss due to diabetes has been witnessed in some developing countries. However, there is a steady increase in the number of people affected with diabetes, and is expected to rise further in the coming years. Therefore, it is prudent to identify diabetic retinopathy, and timely intervention is needed to decrease the burden of severe vision loss. An effort has been made to review all the existing knowledge regarding diabetic retinopathy in this article and summarize the present treatment options for diabetic retinopathy.

Retinal Findings in Hospitalized COVID-19 Patients, Is Routine Ophthalmological Examination Required after Discharge? Prospective Case-Control Study

OBJECTIVES

To investigate retinal findings by comparing patients hospitalized for COVID-19 with the control group.

METHODS

In this prospective study, 188 eyes of 94 recovered COVID-19 patients and 108 eyes of 54 healthy participants as a control group were evaluated. Patients were divided into three groups, those with mild, moderate, and severe COVID-19. Refractometry, tonometry, optical biometry, optical coherence tomography (OCT) measurements, and complete ophthalmological examinations were performed on healthy volunteers and COVID-19 patients on average 2 weeks after discharge. Pulse O₂ and vital parameters were also assessed. Primary outcomes were evaluated, such as retinal findings, and secondary outcomes as retinal thickness, choroidal thickness (CT), retinal nerve fiber layer thickness, and ganglion cell layer thickness.

RESULTS

There was no difference between the groups in terms of demographic data, ocular biometry, and intraocular pressure (p > 0.05). Pulse O₂ was lower in the study group (p < 0.001). Retinal findings were detected in 68 (36.1%) of 188 eyes in the study group and 28 (25.9%) of 108 eyes in the control group (p = 0.07). The two most common retinal findings were hypertensive retinopathy and retinal pigment epithelium alterations and/or drusen in both groups. In OCT measurements, significant thinning was observed in nasal macular thickness and superior 2 mm CT in the study group compared to the control group (p < 0.05). In patients divided into subgroups according to disease severity, no significant difference was found between the groups in any OCT parameter (p > 0.05).

CONCLUSION

It has been observed that COVID-19 infection does not cause a specific and sensitive finding in the ocular tissues, especially the retina, and does not produce a reproducible measurement result. Recommending routine eye exam after COVID-19 does not seem cost-effective.

Hypertensive eye disease

Hypertensive eye disease includes a spectrum of pathological changes, the most well known being hypertensive retinopathy. Other commonly involved parts of the eye in hypertension include the choroid and optic nerve, sometimes referred to as hypertensive choroidopathy and hypertensive optic neuropathy. Together, hypertensive eye disease develops in response to acute and/or chronic elevation of blood pressure. Major advances in research over the past three decades have greatly enhanced our understanding of the epidemiology, systemic associations and clinical implications of hypertensive eye disease, particularly hypertensive retinopathy. Traditionally diagnosed via a clinical funduscopic examination, but increasingly documented on digital retinal fundus photographs, hypertensive retinopathy has long been considered a marker of systemic target organ damage (for example, kidney disease) elsewhere in the body. Epidemiological studies indicate that hypertensive retinopathy signs are commonly seen in the general adult population, are associated with subclinical measures of vascular disease and predict risk of incident clinical cardiovascular events. New technologies, including development of non-invasive optical coherence tomography angiography, artificial intelligence and mobile ocular imaging instruments, have allowed further assessment and understanding of the ocular manifestations of hypertension and increase the potential that ocular imaging could be used for hypertension management and cardiovascular risk stratification.

The role of hesperidin in ameliorating retinal changes in rats with experimentally induced type 1 diabetes mellitus and the active role of vascular endothelial growth factor and glial fibrillary acidic protein

Patients with type 1 diabetes mellitus (T₁DM) are vulnerable to developing diabetic retinopathy even under insulin therapy. Thus, this study was designed to evaluate the efficacy of hesperidin and insulin in rats with T₁DM compared with insulin alone in improving diabetic retinal changes. Eighty rats were divided into four equal groups: group I, control rats without diabetes; group II, untreated rats with diabetes; group III, rats with diabetes treated daily with subcutaneous (SC) doses of long-acting insulin; and group IV, a rat with diabetes in which hesperidin was orally administered with SC insulin. The animals were assessed histologically, morphometrically, and biochemically. In group II, the thickness of all retinal layers decreased histologically. Ultrastructurally, degenerated retinal neurons and congested blood vessels were observed. Immunostaining detected elevated gene expression of advanced glycation end products. Gene expression of vascular endothelial growth factor, and glial fibrillary acidic protein were elevated. In this study, hesperidin supplementation with insulin significantly improved the retinal histological changes, supported by morphometric findings, compared with insulin alone. Moreover, treatment with hesperidin significantly reduced malondialdehyde and elevated serum antioxidant markers, including superoxide dismutase and catalase; furthermore, glutathione peroxidase decreased. Hesperidin might be an effective supplement for improving diabetic retinal complications occurring even with insulin treatment.

Animal models of diabetic microvascular complications: Relevance to clinical features

Diabetes has become more common in recent years worldwide, and this growth is projected to continue in the future. The primary concern with diabetes is developing various complications, which significantly contribute to the disease's mortality and morbidity. Over time, the condition progresses from the pre-diabetic to the diabetic stage and then to the development of complications. Years and enormous resources are required to evaluate pharmacological interventions to prevent or delay the progression of disease or complications in humans. Appropriate screening models are required to gain a better understanding of both pathogenesis and potential therapeutic agents. Different species of animals are used to evaluate the pharmacological potentials and study the pathogenesis of the disease. Animal models are essential for research because they represent most of the structural, functional, and biochemical characteristics of human diseases. An ideal screening model should mimic the pathogenesis of the disease with identifiable characteristics. A thorough understanding of animal models is required for the experimental design to select an appropriate model. Each animal model has certain advantages and limitations. The present manuscript describes the animal models and their diagnostic characteristics to evaluate microvascular diabetic complications.

Retinal microvascular findings and risk of incident peripheral artery disease: An analysis from the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND AND AIMS

Lower-extremity peripheral artery disease (PAD) is usually considered large artery disease. Interestingly, retinal microvascular findings were shown to predict PAD progression in diabetes. However, it is unknown whether retinal microvascular parameters are associated with incident PAD and its severe form, critical limb ischemia (CLI), in a community-based cohort.

METHODS

Among 9371 ARIC participants (aged 49-72 years) free of a history of PAD, we quantified the associations of several retinal measures by retinal photography during the period 1993-1995 with PAD risk using Cox models. Incident PAD was defined as the first hospitalization with PAD diagnosis or leg revascularization (considered CLI if an additional diagnosis of ulcer, gangrene, or amputation).

RESULTS

During a median follow-up of 18.8 years, 303 participants developed PAD (including 91 CLI cases). Although generalized retinal arteriolar narrowing was not associated with PAD, most measures of retinopathy demonstrated strong associations with PAD beyond potential confounders including diabetes, with adjusted hazard ratios (HR) of 3.26 (95% CI 2.18-4.90) for blot-shaped hemorrhages, 3.11 (1.83-5.29) for hard exudates, and 2.18 (1.62-2.95) for any retinopathy. Adjusted HRs were significantly greater for CLI (ranging from 3.2 to 5.9) than for PAD (all p-values <0.05). Retinopathy measures showed particularly strong associations in participants with diabetes (p-value for interaction [vs. those without diabetes] <0.001).

CONCLUSIONS

Several retinopathy measures were strongly associated with PAD, especially with CLI and in diabetes. Our results support the contribution of microvascular abnormalities to the development and progression of PAD and would have implications on its preventive and therapeutic approaches.

Retinal vascular imaging technology to monitor disease severity and complications in type 1 diabetes mellitus: A systematic review

OBJECTIVE

Type 1 diabetes mellitus (T1DM) is a major disease affecting a large number of young patients. In the recent years, retinal vascular imaging has provided an objective assessment of vascular health in patients with T1DM. Our study aimed to review the current literature on retinal vascular parameters in young patients with T1DM in order to understand the following: (i) How retinal vessels are affected in T1DM (ii) How such vascular changes can be predictive of future diabetic microvascular complications METHODS: We performed a systematic review and extracted relevant data from 17 articles.

RESULTS

We found significant correlations between retinal vessel changes and diabetes-related risk factors (eg, hypertension, hyperlipidemia, and obesity), diabetes-related features (eg, diabetes duration and glycemic control), and diabetes-related microvascular complications (eg, diabetic retinopathy, nephropathy, and neuropathy).

CONCLUSION

Our findings suggest that retinal microvasculature is associated with both disease severity and complications in young patients with T1DM.

Serum uric acid concentration is associated with hypertensive retinopathy in hypertensive chinese adults

BACKGROUND

This cross sectional investigation included 12,966 subjects with hypertension, a cohort of the China Stroke Primary Prevention Trial (CSPPT), a randomized, multicenter clinical trial. This study aimed to explore the correlation between serum uric acid (SUA) concentration and hypertensive retinopathy in hypertensive adults.

METHODS

Diagnosis of hypertensive retinopathy was determined by non-mydriatic fundus photography and classified with Keith-Wagener-Barker (KWB) system. The correlation of SUA levels with hypertensive retinopathy prevalence and severity was assessed by statistical analysis.

RESULTS

9848 (75.95%) subjects were diagnosed with hypertensive retinopathy with the following retinopathy grade distribution: grade 1: 58.80%, grade 2: 14.81%, and grade 3-4: 2.34%. SUA levels were significantly associated with hypertensive retinopathy prevalence. Patients with hypertensive retinopathy had higher SUA levels than those without hypertensive retinopathy. Patients in the highest uric acid quartile had an odds ratio for hypertensive retinopathy of 1.21 compared to patients in the lowest uric acid quartile (OR = 1.21, 95% CI: 1.05-1.40, P = 0.008). When compared to the non-hyperuricemia group, those in the hyperuricemia group had an odds ratio for hypertensive retinopathy of 1.18(OR = 1.18, 95% CI: 1.05-1.33, P = 0.004). Every 1 mg/dl increase in uric acid concentration was significantly associated with a 6% higher odds of hypertensive retinopathy (OR = 1.06, 95% CI: 1.02-1.10, P = 0.002).

CONCLUSIONS

The prevalence of hypertensive retinopathy was high (75.95%) among hypertensives in our patients cohort. In addition, SUA concentration was significantly associated with hypertensive retinopathy.

Poor outcomes despite aspirin or statin use in high-risk patients with retinal vein occlusion

PURPOSE

Since atherosclerosis contributes to the pathophysiology of retinal vein occlusion (RVO), we aimed to assess the effects of aspirin and statins on the visual outcomes of RVO in high-risk patients, whom we define to have hypertension and open-angle glaucoma prior to RVO.

METHODS

We conducted a retrospective case-control study of adults diagnosed with RVO between 2006 and 2014. To evaluate for a preventive effect of these medications, we compared the prevalence of aspirin or statin use (either separately or concomitantly) among high-risk patients who developed RVO and among those who did not during at least 2 years of follow-up. To evaluate for a therapeutic effect, we then compared the final follow-up visual acuity (VA) of high-risk RVO patients who had and who had not been taking a statin prior to the RVO.

RESULTS

We analyzed 43 eyes [23 central RVOs (CRVOs), 16 branch RVOs (BRVOs), and 4 hemi-RVOs (HRVOs)] from 42 high-risk patients, along with 129 high-risk controls. There was no significant difference (p = 0.47) in aspirin exposure between the control (60%) and RVO (67%) groups, and the increased statin exposure among controls (72% vs. 53% for the cases; p = 0.03) paralleled their higher prevalence of hyperlipidemia. The non-statin and statin RVO groups each had a mean VA of 20/800 at a mean 30 and 43 months of follow-up, respectively.

CONCLUSIONS

No preventive benefit of aspirin or statins, and no therapeutic benefit of statins, was found for RVO in high-risk patients. High-risk RVO patients suffer substantially worse outcomes than those reported in other studies not limited to such patients.

Mortality in Older Persons with Retinopathy and Concomitant Health Conditions: The Age, Gene/Environment Susceptibility-Reykjavik Study

PURPOSE

To assess the impact of retinopathy on mortality in older persons with concomitant health conditions.

DESIGN

Population-based prospective cohort study.

PARTICIPANTS

A total of 4966 individuals aged 67 to 96 years (43.2% were male) from the Age, Gene/Environment Susceptibility-Reykjavik Study (AGES-RS).

METHODS

Retinopathy was evaluated from digital fundus images (2002-2006) using the modified Airlie House adaptation of the Early Treatment Diabetic Retinopathy Study protocol. Mortality was assessed through September 2013 (cause of death assigned through 2009). Cox proportional hazards regression models, with age as the time scale, estimated the association between retinopathy and death while controlling for risk factors and the presence of concomitant health conditions.

MAIN OUTCOME MEASURES

Mortality from all causes and cardiovascular disease (CVD).

RESULTS

Among the 4966 participants, 503 (10.1%) had diabetes and 614 (12.4%) had retinopathy at baseline. A subset of these (136 [2.7%]) had both diabetes and retinopathy. After a median follow-up of 8.6 years, 1763 persons died, 276 (45.0%) with retinopathy and 1487 (34.2%) without retinopathy, of whom 76 and 162 persons, respectively, also had diabetes. There were 366 deaths from CVD through 2009, 72 (11.7%) in persons with retinopathy and 294 (6.8%) in those without retinopathy. In multivariable analyses, retinopathy was significantly associated with all-cause mortality (hazard ratio [HR], 1.26; 95% confidence interval [CI], 1.10-1.43; P < 0.01) and CVD-related mortality (HR, 1.57; 95% CI, 1.20-2.06; P < 0.01). Findings were more striking in men: all-cause HR, 1.33 (95% CI, 1.11-1.60) and CVD HR, 1.81 (95% CI, 1.25-2.63). Risk of mortality was further increased among those with retinopathy concomitant with microalbuminuria (all-cause HR, 1.70; 95% CI, 1.03-2.23, and CVD HR, 2.04; 95% CI, 1.27-3.28) and those with retinopathy, microalbuminuria, and diabetes (all-cause HR, 2.01; 95% CI, 1.22-3.31, and CVD HR, 5.24; 95% CI, 1.91-14.42). History of clinical stroke increased the risk of CVD-related mortality among persons with retinopathy (HR, 3.30; 95% CI, 2.05-5.32), particularly those with retinopathy and diabetes (HR, 5.38; 95% CI, 1.80-16.06).

CONCLUSIONS

Even minimal retinopathy was a significant predictor of increased mortality in older persons, particularly men, irrespective of diabetes status. Persons with retinopathy may warrant closer clinical management of general health.

Hypertensive retinopathy in a transgenic angiotensin-based model

Severe hypertension destroys eyesight. The RAS (renin-angiotensin system) may contribute to this. This study relied on an established angiotensin, AngII (angiotensin II)-elevated dTGR (double-transgenic rat) model and same-background SD (Sprague-Dawley) rat controls. In dTGRs, plasma levels of AngII were increased. We determined the general retinal phenotype and observed degeneration of ganglion cells that we defined as vascular degeneration. We also inspected relevant gene expression and lastly observed alterations in the outer blood-retinal barrier. We found that both scotopic a-wave and b-wave as well as oscillatory potential amplitude were significantly decreased in dTGRs, compared with SD rat controls. However, the b/a-wave ratio remained unchanged. Fluorescence angiography of the peripheral retina indicated that exudates, or fluorescein leakage, from peripheral vessels were increased in dTGRs compared with controls. Immunohistological analysis of blood vessels in retina whole-mount preparations showed structural alterations in the retina of dTGRs. We then determined the general retinal phenotype. We observed the degeneration of ganglion cells, defined vascular degenerations and finally found differential expression of RAS-related genes and angiogenic genes. We found the expression of both human angiotensinogen and human renin in the hypertensive retina. Although the renin gene expression was not altered, the AngII levels in the retina were increased 4-fold in the dTGR retina compared with that in SD rats, a finding with mechanistic implications. We suggest that alterations in the outer blood-retinal barrier could foster an area of visual-related research based on our findings. Finally, we introduce the dTGR model of retinal disease.

Diabetic retinopathy

Diabetic retinopathy (DR) is a common complication of diabetes mellitus and is a major cause of vision loss in middle-aged and elderly people. One-third of people with diabetes have DR. Severe stages of DR include proliferative DR, caused by the abnormal growth of new retinal blood vessels, and diabetic macular oedema, in which there is exudation and oedema in the central part of the retina. DR is strongly associated with a prolonged duration of diabetes, hyperglycaemia and hypertension. It is traditionally regarded as a microvascular disease, but retinal neurodegeneration is also involved. Complex interrelated pathophysiological mechanisms triggered by hyperglycaemia underlie the development of DR. These mechanisms include genetic and epigenetic factors, increased production of free radicals, advanced glycosylation end products, inflammatory factors and vascular endothelial growth factor (VEGF). Optimal control of blood glucose and blood pressure in individuals with diabetes remains the cornerstone for preventing the development and arresting the progression of DR. Anti-VEGF therapy is currently indicated for diabetic macular oedema associated with vision loss, whereas laser photocoagulation prevents severe vision loss in eyes with proliferative DR. These measures, together with increasing public awareness and access to regular screening for DR with retinal photography, and the development of new treatments to address early disease stages, will lead to better outcomes and prevent blindness for patients with DR.

Imaging rhodopsin degeneration in vivo in a new model of ocular ischemia in living mice

Delivery of antibodies to monitor key biomarkers of retinopathy in vivo represents a significant challenge because living cells do not take up immunoglobulins to cellular antigens. We met this challenge by developing novel contrast agents for retinopathy, which we used with magnetic resonance imaging (MRI). Biotinylated rabbit polyclonal to chick IgY (rIgPxcIgY) and phosphorylthioate-modified oligoDNA (sODN) with random sequence (bio-sODN-Ran) were conjugated with NeutrAvidin-activated superparamagnetic iron oxide nanoparticles (SPION). The resulting Ran-SPION-rIgPxcIgY carries chick polyclonal to microtubule-associated protein 2 (MAP2) as Ran-SPION-rIgP/cIgY-MAP2, or to rhodopsin (Rho) as anti-Rho-SPION-Ran. We examined the uptake of Ran-SPION-rIgP/cIgY-MAP2 or SPION-rIgP/cIgY-MAP2 in normal C57black6 mice (n = 3 each, 40 μg/kg, i.c.v.); we found retention of Ran-SPION-rIgP/cIgY-MAP2 using molecular contrast-enhanced MRI in vivo and validated neuronal uptake using Cy5-goat IgPxcIgY ex vivo. Applying this novel method to monitor retinopathy in a bilateral carotid artery occlusion-induced ocular ischemia, we observed pericytes (at d 2, using Gd-nestin, by eyedrop solution), significant photoreceptor degeneration (at d 20, using anti-Rho-SPION-Ran, eyedrops, P = 0.03, Student's t test), and gliosis in Müller cells (at 6 mo, using SPION-glial fibrillary acidic protein administered by intraperitoneal injection) in surviving mice (n ≥ 5). Molecular contrast-enhanced MRI results were confirmed by optical and electron microscopy. We conclude that chimera and molecular contrast-enhanced MRI provide sufficient sensitivity for monitoring retinopathy and for theranostic applications.

Diabetes retinopathy is a poor predictor for renal and cardiovascular outcomes in comparison with hypertensive retinopathy in patients with chronic kidney disease

AIMS

Chronic kidney disease (CKD) and retinopathy share the common pathophysiology of microvascular dysfunction. It is unclear whether the clinical significance of diabetic retinopathy (DMR) and hypertensive retinopathy (HTNR) differs in CKD patients.

METHODS

We included 684 nondialysis-dependent CKD stage 3-5 patients with diabetes or hypertension: 501 patients with diabetes and 183 with hypertension. The clinical significance of DMR and HTNR was evaluated in terms of the rate of renal function decline and composite of any cardiovascular event or death.

RESULTS

DMR was observed in 261 (52.1%) CKD patients with diabetes, and HTNR in 44 (24.0%) CKD patients with hypertension. In the diabetes group, the renal function decline rate was significantly steeper in patients with than in those without DMR (-7.4 ± 9.8mL/min/1.73m(2)/yr vs. -2.4 ± 7.6mL/min/1.73m(2)/yr; P<0.001). In multivariate analysis, DMR were independently associated with a rapid decline in renal function (β=-2.44; P=0.20). However, HTNR did not affect the renal function decline in CKD patients. The composite event-free survival rate was lower in patients with diabetes and DMR than in those without DMR (P=0.043). Patients with diabetes and DMR were independently associated with a 2.13-fold increased risk for composite events (P=0.010). HTNR was not associated with higher risk for composite events in CKD patients.

CONCLUSION

Coexistence of diabetes and DMR were independently associated with CKD progression and composite cardiovascular event/death, but the clinical significance of HTNR is less clear in CKD patients.

Novel Method for Automated Analysis of Retinal Images: Results in Subjects with Hypertensive Retinopathy and CADASIL

Morphological analysis of the retinal vessels by fundoscopy provides noninvasive means for detecting and staging systemic microvascular damage. However, full exploitation of fundoscopy in clinical settings is limited by paucity of quantitative, objective information obtainable through the observer-driven evaluations currently employed in routine practice. Here, we report on the development of a semiautomated, computer-based method to assess retinal vessel morphology. The method allows simultaneous and operator-independent quantitative assessment of arteriole-to-venule ratio, tortuosity index, and mean fractal dimension. The method was implemented in two conditions known for being associated with retinal vessel changes: hypertensive retinopathy and Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL). The results showed that our approach is effective in detecting and quantifying the retinal vessel abnormalities. Arteriole-to-venule ratio, tortuosity index, and mean fractal dimension were altered in the subjects with hypertensive retinopathy or CADASIL with respect to age- and gender-matched controls. The interrater reliability was excellent for all the three indices (intraclass correlation coefficient ≥ 85%). The method represents simple and highly reproducible means for discriminating pathological conditions characterized by morphological changes of retinal vessels. The advantages of our method include simultaneous and operator-independent assessment of different parameters and improved reliability of the measurements.

Safety Profile and Effects of Pulsed Methylprednisolone on Vital Signs in Thyroid Eye Disease

Objective. To analyze changes in vital signs (heart rate (HR), systolic (SBP), and diastolic blood pressure (DBP)) during and after intravenous methylprednisolone (IVMP) and any other adverse effects. Methods. Retrospective review of charts of patients who received IVMP as treatment regime for thyroid eye disease. All subjects had vital signs charted during and after infusions. Results. This study included 38 subjects and a total of 242 infusions administered. IVMP resulted in a small but significant percentage drop in mean SBP at 30 min (p < 0.001) and 60 min (p = 0.03) but no difference at 90 min. There was also small but significant percentage drop in mean DBP and HR (DBP: p < 0.001 for 30 min, p = 0.001 for 60 min, and p = 0.02 for 90 min and HR: p < 0.001 for 30 min, 60 min, and 90 min). There were no cumulative effects on change of blood pressure or HR. There were 6 episodes of bradycardia (2.5%) and 12 episodes of moderate to severe hypertension (5%). No significant cardiovascular or hepatic toxicity was found. Conclusion. IVMP is relatively safe and efficacious. IVMP demonstrated mild and noncumulative effects on vital signs. Severe hypertension may occur in susceptible individuals such as those with underlying hypertension and uncontrolled thyroid dysfunction, whereas bradycardia may be more likely in those on beta-blockers.

Microcirculatory marker for the prediction of renal end points: a prospective cohort study in patients with chronic kidney disease stage 2 to 4

Retinal arteriolar narrowing reflects aging, hypertension, chronic kidney disease (CKD), and other vascular processes. We examined the predictive value of retinal arteriolar narrowing alone and in combination with albuminuria on renal disease progression in CKD. A white CKD stage 2 to 4 cohort of 164 men and women (60.8±13.8 years) underwent retinal photography and determination of albuminuria. The calibers of all retinal arterioles were measured after digital conversion of the photographs. Cases of incident renal end points defined as 50% renal function loss and start of renal replacement therapy were identified and validated by case record reviews. Over an average period of 1410 (range, 106-1606) days, 25 patients with CKD had incident renal end points. Kaplan-Meier analysis revealed that patients with CKD within the tertile of narrowest arterioles had more renal end points (log-rank P<0.001). Cox regression analysis confirmed this before (β=1.183±0.411) and after adjusting for age and baseline renal function (β=1.204±0.416). With respect to renal end points, a significant interaction was present between narrow arterioles and albuminuria. The relative risk for renal end points of narrow arterioles was 3.7 (1.7-8.4), of albuminuria was 5.4 (2.5-12.0), and of combined narrow arterioles and albuminuria was 16.2 (4.6-57.2). Hence retinal arteriolar narrowing is related to incident renal end points. Narrow arterioles and albuminuria reveal a synergistic predictive value. The findings support a leading role of the microvasculature in the pathogenesis of renal disease progression. They also suggest that retinal photography in combination with albuminuria determination may be useful for risk stratification with respect to renal disease progression in patients with CKD stage 2 to 4.

[Hypertension-related eye disorders]

Hypertension affects a significant proportion of the population, however, it is often diagnosed with a delay. The aim of this article is to review the well known and less known eye abnormalities related to hypertension, and place them in the context of population based studies. Hypertension affects various parts of the eye. The originally classified hypertensive retinopathy (retinal microvascular changes) is still relevant, but new features are visible in cases of controlled hypertension. Signs of mild hypertensive retinopathy are more common than expected occurring in nearly 10-15% of the adult non-diabetic population. Hypertensive retinopathy can be an indicator of other hypertensive complications such as neurologic and cardiac complications. Microvascular changes are reversible in well controlled hypertension. Proper treatment of hypertension can reduce the development and progression of diabetic retinopathy and, thus, visual loss due to severe retinal diseases such as retinal vascular occlusion (artery and vein), retinal arteriolar emboli, macroaneurysm, ischemic optic neuropathy and age-related macular degeneration.

Inflammation, haemostatic disturbance, and obesity: possible link to pathogenesis of diabetic retinopathy in type 2 diabetes

PURPOSE

The pathogenesis of diabetic retinopathy (DR) is insufficiently understood but may possibly involve chronic, low-grade inflammation. The aim of this cross-sectional study was to investigate the relationship between inflammatory and haemostatic markers, other markers of endothelial dysfunction and anthropometric parameters, and their association with DR in patients with type 2 diabetes.

METHODS

According to the DR status patients were divided into three groups: no retinopathy, mild/moderate nonproliferative (NPDR), and severe NPDR/proliferative retinopathy (PDR).

RESULTS

The groups did not differ in the levels of inflammatory and haemostatic markers, other markers of endothelial dysfunction, and anthropometric parameters. After dividing the patients according to the level of obesity (defined by BMI, WC, and WHR) into three groups ANOVA showed the differences in C-reactive protein according to the WC (P = 0.0265) and in fibrinogen according to the WHR (P = 0.0102) as well as in total cholesterol (P = 0.0109) and triglycerides (P = 0.0133) according to the BMI. Logistic regression analyses showed that diabetes duration and prolonged poor glycemic control are the main predictors of retinopathy in patients with type 2 diabetes.

CONCLUSION

Interrelations between obesity, inflammation, haemostatic disturbance, and other risk factors may possibly play an important additional role in endothelial dysfunction involved in the pathogenesis of diabetic retinopathy.

Prevalence and risk factors for diabetic retinopathy in a high-risk Chinese population

Background

Lifestyle plays an important role in the development of diabetic retinopathy. The lifestyle in Guangzhou is different from other cities in China as the Cantonese prefer eating rice porridge, but not spicy foods. The objectives of this study were to investigate the prevalence and determinants of diabetic retinopathy in a high-risk population of Guangzhou.

Methods

Subjects (619 totals) aged over 45 years old, without known diabetes were recruited from five randomly selected Guangzhou communities in 2009–2010. All participants were invited to complete the Finnish Diabetes Risk Score (FINDRISC) questionnaire. Subjects with FINDRISC score ≥ 9 were included in the study, and underwent an investigation of demographic data, a standardized physical examination, ocular fundus examination, and laboratory analyses. The minimum criterion for diagnosis of diabetic retinopathy was the presence of at least one microaneurysm.

Results

Of 619 subjects, 208 eligible subjects (122 women) with FINDRISC score ≥ 9 were included in the study. The mean age was 69.2 ± 8.5 years. Diabetic retinopathy was detected in 31 subjects, and the prevalence of diabetic retinopathy in subjects with high risk for diabetes was 14.9%. In binary logistic regression analysis, risk factors associated with diabetic retinopathy were history of impaired glucose regulation [odds ratio (OR), 7.194; 95% confidence interval (CI): 1.083, 47.810], higher hemoglobin A1c (HbA1c; OR, 2.912; 95% CI: 1.009, 8.402), higher two-hour postprandial plasma glucose level (OR, 1.014; 95% CI: 1.003, 1.025), and presence of microalbuminuria (OR, 5.387; 95% CI: 1.255, 23.129).

Conclusions

Diabetic retinopathy was prevalent in a high-risk Chinese population from Guangzhou. Histories of impaired glucose regulation and microalbuminuria were strong risk factors for diabetic retinopathy.

Associations between retinal microvascular changes and dementia, cognitive functioning, and brain imaging abnormalities: a systematic review

Retinal microvascular changes can be visualized noninvasively and have been associated with cognitive decline and brain changes in relation to aging and vascular disease. We systematically reviewed studies, published between 1990 and November 2012, on the association between retinal microvascular changes and dementia, cognitive functioning, and brain imaging abnormalities, in the context of aging and vascular risk factors. In cross-sectional studies (k=26), retinal microvascular changes were associated with the presence of dementia (range of odds ratios (ORs) 1.17;5.57), with modest decrements in cognitive functioning in nondemented people (effect sizes -0.25;0.03), and with brain imaging abnormalities, including atrophy and vascular lesions (ORs 0.94;2.95). Longitudinal studies were more sparse (k=9) and showed no consistent associations between retinal microvascular changes and dementia or cognitive dysfunctioning 3 to 15 years later (ORs and hazard ratios 0.77;1.55). However, there were indications of prospective associations with brain imaging abnormalities ((ORs) 0.81;3.19). In conclusion, particularly in cross-sectional studies there is a correlation between retinal microvascular changes and dementia, cognitive impairment, and brain imaging abnormalities. Associations are strongest for more severe retinal microvascular abnormalities. Retinal microvascular abnormalities may offer an important window on the brain for etiological studies.

Genome-wide association study of retinopathy in individuals without diabetes

Background

Mild retinopathy (microaneurysms or dot-blot hemorrhages) is observed in persons without diabetes or hypertension and may reflect microvascular disease in other organs. We conducted a genome-wide association study (GWAS) of mild retinopathy in persons without diabetes.

Methods

A working group agreed on phenotype harmonization, covariate selection and analytic plans for within-cohort GWAS. An inverse-variance weighted fixed effects meta-analysis was performed with GWAS results from six cohorts of 19,411 Caucasians. The primary analysis included individuals without diabetes and secondary analyses were stratified by hypertension status. We also singled out the results from single nucleotide polymorphisms (SNPs) previously shown to be associated with diabetes and hypertension, the two most common causes of retinopathy.

Results

No SNPs reached genome-wide significance in the primary analysis or the secondary analysis of participants with hypertension. SNP, rs12155400, in the histone deacetylase 9 gene (HDAC9) on chromosome 7, was associated with retinopathy in analysis of participants without hypertension, −1.3±0.23 (beta ± standard error), p = 6.6×10⁻⁹. Evidence suggests this was a false positive finding. The minor allele frequency was low (∼2%), the quality of the imputation was moderate (r² ∼0.7), and no other common variants in the HDAC9 gene were associated with the outcome. SNPs found to be associated with diabetes and hypertension in other GWAS were not associated with retinopathy in persons without diabetes or in subgroups with or without hypertension.

Conclusions

This GWAS of retinopathy in individuals without diabetes showed little evidence of genetic associations. Further studies are needed to identify genes associated with these signs in order to help unravel novel pathways and determinants of microvascular diseases.

Update on animal models of diabetic retinopathy: from molecular approaches to mice and higher mammals

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes and one of the major causes of blindness worldwide. The pathogenesis of DR has been investigated using several animal models of diabetes. These models have been generated by pharmacological induction, feeding a galactose diet, and spontaneously by selective inbreeding or genetic modification. Among the available animal models, rodents have been studied most extensively owing to their short generation time and the inherited hyperglycemia and/or obesity that affect certain strains. In particular, mice have proven useful for studying DR and evaluating novel therapies because of their amenability to genetic manipulation. Mouse models suitable for replicating the early, non-proliferative stages of the retinopathy have been characterized, but no animal model has yet been found to demonstrate all of the vascular and neural complications that are associated with the advanced, proliferative stages of DR that occur in humans. In this review, we summarize commonly used animal models of DR, and briefly outline the in vivo imaging techniques used for characterization of DR in these models. Through highlighting the ocular pathological findings, clinical implications, advantages and disadvantages of these models, we provide essential information for planning experimental studies of DR that will lead to new strategies for its prevention and treatment.

Alternative pathways in the development of diabetic retinopathy: the renin-angiotensin and kallikrein-kinin systems

Diabetic retinopathy is a common complication of both type 1 and type 2 diabetes and is the leading cause of blindness in people of working age. Current treatment strategies are mostly limited to laser photocoagulation, which restricts proliferative retinopathic changes but also causes irreversible damage to the retina. This review examines two important pathways involved in regulating vascular function and their role in the development of diabetic retinopathy. One, the renin-angiotensin system, is well known and has established angiogenic effects on the retina that increase in diabetic retinopathy. The other, the kallikrein-kinin system, has recently been found to be important in the development of diabetic retinal complications. This review describes the components of the two signalling networks, examines the current animal model studies investigating the role of these pathways in diabetic retinopathy and reviews the clinical studies that have been undertaken examining systemic inhibition of different points in these pathways. These systems are promising targets for therapies aimed at inhibiting the development of diabetic retinopathy and in the future, combination therapies that take advantage of both pathways might result in new treatment options for this debilitating complication of diabetes.

Pegylated interferon-associated retinopathy is frequent in hepatitis C virus patients with hypertension and justifies ophthalmologic screening

Treatment with pegylated interferon alpha (PegIFNα) and ribavirin is still regarded as the standard of care for chronic hepatitis C virus (HCV). Retinopathy has been occasionally described but prospective, longitudinal data are lacking. We investigated the frequency and clinical significance of retinopathy during therapy with PegIFNα and ribavirin in 97 consecutive HCV patients. In all, 54 (55.7%) and 43 (44.3%) patients were treated with PegIFNα 2a and PegIFNα 2b, respectively. Ophthalmologic examination was performed before therapy (baseline), at 3 and 6 months (3T and 6T, respectively) of therapy, and 3 months after the end of therapy (3ET). All patients underwent the baseline and 3T examination, 95.9% and 90.7% of patients underwent 6T and 3ET examination, respectively. Overall, 30.9% of patients developed retinopathy, as defined by the presence of cotton wool spots and/or retinal hemorrhages. Variables significantly associated with retinopathy during treatment were age (P = 0.004), metabolic syndrome (P = 0.05), hypertension (P < 0.0001), cryoglobulinemia (P = 0.05), and preexisting intraocular lesions at baseline (P = 0.01). By multivariate analysis, the only variable independently associated with PegIFNα-associated retinopathy was hypertension (hazard ratio [HR] = 4.99, 95% confidence interval [CI] 2.29-10.89). The frequency of retinopathy was significantly higher in hypertensive patients versus those without hypertension at all timepoints (18.5% versus 5.7% at baseline, P = 0.05; 48.1% versus 15.7% at 3T, P = 0.0009; 68.0% versus 19.1% at 6T, P < 0.0001; 32.0% versus 6.2%, P = 0.0005 at 3ET). In one (1.1%) hypertensive patient, who developed bilateral branch retinal vein occlusion at 6T, the therapy was discontinued. A cost analysis showed that screening for PegIFNα-associated retinopathy was cost-effective as compared with thyroid-stimulating hormone screening.

CONCLUSION

Retinopathy is frequent during treatment with PegIFNα and ribavirin, especially in hypertensive patients, who may develop serious complications. Screening for PegIFNα-associated retinopathy should be recommended for HCV patients with hypertension.

Hypertensive retinopathy: incidence, risk factors, and comorbidities

We aimed to determine the prevalence and risk factors of retinopathy in hypertensive outpatients. Demographic data, accompanying diseases, anthropometric measurements, and blood and urine biochemistry of 655 hypertensive patients were evaluated. Hypertensive retinopathy rate was 66.3% (grade 1, 33.6%; grade 2, 32.7%). Age, duration of hypertension, and systolic blood pressure levels were significant risk factors for retinopathy (P = .048, P = .035, and P = .012, respectively). Any correlations between retinopathy and gender, body mass index, biochemistry, and associated diseases were not found. This study shows that the degree and duration of hypertension increases the incidence of retinopathy. Low-grade retinopathy seems not to be associated with other cardiovascular risks.