Clinical risk factors for retinal artery occlusions: a nationwide case-control study

PURPOSE

This study seeks to examine potential risk factors for the development of retinal artery occlusions (RAO).

METHODS

We used data obtained from Danish nationwide registries to evaluate potential risk factors for RAO present up to 5 years prior to the RAO diagnosis. The study included 5312 patients diagnosed with RAO registered in the Danish National Patient Register and 26,560 controls assessed from the general population matched on sex and age at index date. Adjusted conditional logistic regression was used to estimate the odds ratio of included risk factors for RAO diagnosis. We conducted supplementary analyses stratified on sex and age, and on RAO subtype. In addition, interaction analyses were performed between strata in the stratified analyses.

RESULTS

Risk factors associated with the development of RAO included diabetes, arterial hypertension, ischemic heart disease, peripheral artery disease, stroke, renal disease, cataract, and glaucoma, with ORs ranging from 1.33 to 4.94. Atrial fibrillation and sleep apnea yielded effect measures close to equivalence. The presence of a risk factor was generally associated with higher odds of RAO among the population ≤ 55 of age. Arterial hypertension was stronger associated with RAO in male patients than in female patients. The association with arterial hypertension was stronger for CRAO than for BRAO subtype.

CONCLUSION

The investigated risk factors suggest that atherosclerosis and conditions changing the intraocular pressure are involved in the pathophysiology of RAO.

Factors Associated With Nonattendance in a Nationwide Screening Program for Diabetic Retinopathy: A Register-Based Cohort Study

OBJECTIVE

The aim of the study was to identify factors associated with nonattendance in a Danish nationwide screening program for diabetic retinopathy among people with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A retrospective observational study linking individual-level register data was performed. First, we compared characteristics of 156,878 people with type 2 diabetes divided into attenders and never-attenders on the basis of their screening history over a 6-year period. Second, we assessed 230,173 screening intervals within the same 6-year period. Mixed-effects models were used to investigate the effect of sociodemographic and health-related factors on the likelihood of having a nonattender interval (i.e., failing to attend screening within the recommended interval).

RESULTS

A total of 42,068 (26.8%) people were identified as never-attenders, having no registered eye screening over a 6-year period. Compared with attenders, never-attenders were more frequently divorced/widowed, lived in the Capital Region of Denmark, and had poorer health. A total of 62,381 (27.1%) screening intervals were identified as nonattender intervals. Both sociodemographic and health-related factors were significantly associated with the likelihood of having a nonattender interval. The largest odds ratios for nonattendance were seen for mental illness, nonwestern descent, divorce, comorbidity, and place of residence.

CONCLUSIONS

Our findings suggest that never- and nonattendance of screening for diabetic retinopathy are more common among people who are divorced/widowed and of poorer health. Additionally, nonattendance is more frequent among people of nonwestern decent. These population subgroups may benefit from targeted interventions aimed at increasing participation in diabetic retinopathy screening.

Prevalence of Open-angle Glaucoma in the Faroese Population

PURPOSE

The Faroe Islands are home to 50,000 genetically isolated people in the North Atlantic. The prevalence of open-angle glaucoma (OAG) in the Faroese population is unknown. Consequently, we conducted a survey to determine the prevalence of OAG in the Faroese population. We also investigated the role of known glaucoma-causing genes in Faroese OAG.

MATERIALS AND METHODS

We conducted a prospective survey of known and newly diagnosed glaucoma patients at the Faroese National Hospital, Landssjukrahusid, Tórshavn between October 1, 2015 to December 31, 2017. In addition we reviewed the only eye care provider in the Faroese Islands by scrutinizing electronic medical records between 2009 and June 15, 2014, October 1, 2015 and the partly overlapping prescriptions for ocular hypotensive medications in 2016 to identify patients with either a diagnosis of glaucoma, a diagnosis of ocular hypertension or a prescription for ocular hypotensive medications. Next, we prospectively confirmed diagnoses with complete eye examinations. Patient DNA samples were tested for variations in known glaucoma-causing genes [myocilin (MYOC), optineurin (OPTN), and TANK binding kinase 1 (TBK1)].

RESULTS

We determined the age-related prevalence of OAG January 1, 2017 in individuals 40 years or older to be 10.7/1000 (1.07%) and highly age-related. A diagnosis of OAG was present in 264 patients, of whom 211 (79.9%) had primary OAG (including normal tension glaucoma), 49 (18.6%) had pseudoexfoliation glaucoma, and 4 (1.5%) had pigmentary glaucoma. Among patients receiving medications for glaucoma, nearly 50% had primary OAG, while the majority of the rest had ocular hypertension or secondary glaucoma. No disease-causing variants were detected in MYOC, OPTN, or TBK1.

CONCLUSIONS

The calculated prevalence of OAG in the Faroe Islands was 1.07%. The absence of MYOC, OPTN, or TBK1 disease-causing variants in Faroese primary OAG patients suggests that a different, potentially unique set of genes may be contributing to the pathogenesis of glaucoma in this population.

Liraglutide Treatment Does Not Induce Changes in the Peripapillary Retinal Nerve Fiber Layer Thickness in Patients with Diabetic Retinopathy

Purpose: Liraglutide treatment has shown promising anti-inflammatory and nerve regenerative results in preclinical and clinical trials. We sought to assess if liraglutide treatment would induce nerve regeneration through its anti-inflammatory and neurotrophic mechanisms by increasing peripapillary retinal nerve fiber layer (RNFL) thickness in individuals with long-term type 1 diabetes. Methods: Secondary analyses were performed on a prospective, double-blinded, randomized, placebo-controlled trial on adults with type 1 diabetes, distal symmetric polyneuropathy (DSPN), and confirmed diabetic retinopathy, who were randomized 1:1 to either 26 weeks placebo or liraglutide treatment. The primary endpoint was a change in peripapillary RNFL thickness between treatments, assessed by optical coherence tomography. Results: Thirty-seven participants were included in the secondary analysis. No differences in mean peripapillary RNFL thickness (overall ΔMean RNFL thickness; liraglutide -1 (±8) μm (-1%) vs. placebo -1 (±5) μm (-1%), P = 0.78, n = 37) or any of the quadrants. Peripapillary RNFL thicknesses were shown between treatments in either nonproliferative (ΔMean RNFL thickness; liraglutide -1 (±5) μm (-1%) vs. placebo 0 (±4) μm (0%), P = 0.80, N = 26) or proliferative diabetic retinopathy subgroup (ΔMean RNFL thickness; liraglutide -2 (±14) μm (-3%) vs. placebo -1 (±6) μm (-2%), P = 0.88, N = 11). Conclusions: In this study, 26 weeks of liraglutide treatment did not induce measurable changes in the assessed optic nerve thickness. Thus, this methodology does not support the induction of substantial nerve regeneration in this cohort with established retinopathy and DSPN. The trial was approved by the Danish Health and Medicines Authority. Informed consent was obtained from all participants. TODINELI study: EUDRA CT: 2013-004375-12, Ethics Ref: N-20130077 Clinical trial registration number: clinicaltrials.gov NCT02138045.

Similarities and differences in risk factors for retinal artery occlusion and stroke

Background

Retinal artery occlusion and stroke share several risk factors and have been defined as equivalent diseases by the American Heart Association and American Stroke Association (1,2).

Purpose

The purpose of this study was to compare risk factors between RAO and stroke. Similarities and differences were addressed and the pathophysiology of the two diseases discussed.

Methods

This study was conducted as a case-control study, using data from the Danish nationwide registries to identify personal information, diagnoses, and prescriptions. Study subjects were included between 1st of January 2000 and 31st of December 2018, resulting in 5683 RAO cases. The cases were matched on year of birth, sex, and year of diagnosis with 5 random stroke patients. Risk factors from up to 5 years prior to the index date were included and associations were investigated with adjusted conditional logistic regression.

Results

The clinical risk factors investigated between RAO and stroke showed both differences and similarities. The effect measures for diabetes, renal disease, IHD, AMI, and HF were close to equivalence and we assessed the association between these risk factors and both RAO and stroke were comparable. Differences in the association of the included risk factors between RAO and stroke were identified. The association between AF and stroke was stronger compared to RAO, whereas a stronger association was found between RAO and cataract, glaucoma, RVO, hypertension, and PAD.

The shared risk factors for RAO and stroke support the strong association between the two diseases. The shared risk factors are all associated or diseases of the cardiovascular system, supporting thromboembolism as the pathogenesis of both diseases. The identified differences may indicate variations in the pathophysiology for RAO and stroke, respectively. First, the included eye diseases are associated with changes in the pressure gradients of the eye and indicate that these pressure gradients increase the risk of RAO significantly more compared to stroke (3–5). Second, AF is a major cause of cardiogenic embolization (6–9). The stronger association between AF and stroke may indicate that cardiogenic embolization is more prevalent in stroke patients compared to RAO patients. Finally, hypertension and peripheral artery disease are associated with atherosclerotic embolization and the stronger association between both hypertension and peripheral artery disease and RAO may indicate atherosclerotic embolization is the main pathophysiology of RAO (6,10–12).

Conclusion

This study found similarities and differences between the risk factors for RAO and stroke. The results indicated that RAO may be stronger associated with eye diseases and atherosclerotic embolization, whereas stroke may be stronger associated with cardiogenic embolization.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): The Obel Family Foundation Table 1. Comparing risk factors between RAO and strokeFigure 1. Possible pathophysiology

Risk of Stroke, Myocardial Infarction, and Death Among Patients With Retinal Artery Occlusion and the Effect of Antithrombotic Treatment

Purpose

To evaluate the risk of future stroke, myocardial infarction (MI), and death of patients with retinal artery occlusion (RAO) and the effect of various antithrombotic treatments as secondary prevention.

Methods

This cohort study was based on nationwide health registries and included the entire Danish population from 2000 to 2018. All patients with RAO were identified and their adjusted risks of stroke, MI, or death in time periods since RAO were compared with those of the Danish population. Furthermore, antithrombotic treatment of patients with RAO was determined by prescription claims, and the association with the risk of stroke, MI, or death was assessed using multivariate Poisson regression models and expressed as rate ratios (RR) with 95% confidence intervals (95% CIs).

Results

After inclusion, 6628 individuals experienced a first-time RAO, of whom 391 had a stroke, 66 had a MI, and 402 died within the first year after RAO. RAO was associated with an increased risk of stroke, MI, or death which persisted for more than 1 year for all three outcomes but was highest on days 3 to 14 after RAO for stroke, with an adjusted RR of 50.71 (95% CI, 41.55–61.87), and on days 14 to 90 after RAO for MI and death, with adjusted RRs of 1.98 (95% CI, 1.25–3.15) and 1.64 (95% CI, 1.28–189), respectively. Overall, antithrombotic treatment was not associated with any protective effect the first year.

Conclusions

Patients with RAO had an increased risk of stroke, MI, or death. No protective effect of antithrombotic treatment was shown.

Translational Relevance

These findings are relevant to the management of patients with RAO.

Perfusion Changes in Acute Stroke Treated with Theophylline as an Add-on to Thrombolysis : A Randomized Clinical Trial Subgroup Analysis

PURPOSE

Theophylline has been suggested to have a neuroprotective effect in ischemic stroke; however, results from animal stroke models and clinical trials in humans are controversial. The aim of this study was to assess the effect of theophylline on the cerebral perfusion with multiparametric magnetic resonance imaging (MRI).

METHODS

The relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), and relative mean transit time (rMTT) in the infarct core, penumbra, and unaffected tissue were measured using multi-parametric MRI at baseline and 3‑h follow-up in patients treated with theophylline or placebo as an add-on to thrombolytic therapy.

RESULTS

No significant differences in mean rCBF, rCBV, and rMTT was found in the penumbra and unaffected tissue between the theophylline group and the control group between baseline and 3‑h follow-up. In the infarct core, mean rCBV increased on average by 0.05 in the theophylline group and decreased by 0.14 in the control group (p < 0.04). Mean rCBF and mean rMTT in the infarct core were similar between the two treatment groups.

CONCLUSION

The results indicate that theophylline does not change the perfusion in potentially salvageable penumbral tissue but only affects the rCBV in the infarct core. In contrast to the penumbra, the infarct core is unlikely to be salvageable, which might explain why theophylline failed in clinical trials.

Machine Learning-Based Prediction of Brain Tissue Infarction in Patients With Acute Ischemic Stroke Treated With Theophylline as an Add-On to Thrombolytic Therapy: A Randomized Clinical Trial Subgroup Analysis

Background and Purpose: The theophylline in acute ischemic stroke trial investigated the neuroprotective effect of theophylline as an add-on to thrombolytic therapy in patients with acute ischemic stroke. The aim of this pre-planned subgroup analysis was to use predictive modeling to virtually test for differences in the follow-up lesion volumes.

Materials and Methods: A subgroup of 52 patients from the theophylline in acute ischemic stroke trial with multi-parametric MRI data acquired at baseline and at 24-h follow-up were analyzed. A machine learning model using voxel-by-voxel information from diffusion- and perfusion-weighted MRI and clinical parameters was used to predict the infarct volume for each individual patient and both treatment arms. After training of the two predictive models, two virtual lesion outcomes were available for each patient, one lesion predicted for theophylline treatment and one lesion predicted for placebo treatment.

Results: The mean predicted volume of follow-up lesions was 11.4 ml (standard deviation 18.7) for patients virtually treated with theophylline and 11.2 ml (standard deviation 17.3) for patients virtually treated with placebo (p = 0.86).

Conclusions: The predicted follow-up brain lesions for each patient were not significantly different for patients virtually treated with theophylline or placebo, as an add-on to thrombolytic therapy. Thus, this study confirmed the lack of neuroprotective effect of theophylline shown in the main clinical trial and is contrary to the results from preclinical stroke models.

Aqueous Fibronectin Correlates With Severity of Macular Edema and Visual Acuity in Patients With Branch Retinal Vein Occlusion: A Proteome Study

Purpose

Large-scale protein analysis may bring important insights into molecular changes following branch retinal vein occlusion (BRVO). Using proteomic techniques this study compared aqueous humor samples from patients with BRVO to age-matched controls.

Methods

Aqueous humor samples from treatment naive patients with BRVO complicated by macular edema (n = 19) and age-matched controls (n = 18) were analyzed with label-free quantification nano liquid chromatography - tandem mass spectrometry (LFQ nLC-MS/MS). The severity of macular edema was measured as central retinal thickness (CRT) with optical coherence tomography. Control samples were obtained prior to cataract surgery. Proteins were filtered by requiring quantification in at least 50% of the samples in each group without imputation of missing values. Significantly changed proteins were identified with a permutation-based calculation with a false discovery rate at 0.05.

Results

In BRVO, 52 proteins were differentially expressed. Regulated proteins were involved in cell adhesion, coagulation, and acute-phase response. Apolipoprotein C-III, complement C3, complement C5, complement factor H, fibronectin, and fibrinogen chains were increased in BRVO and correlated with CRT. Fibronectin also correlated with best corrected visual acuity (BCVA) and vascular endothelial growth factor (VEGF). Monocyte differentiation antigen CD14 (CD14) and lipopolysaccharide-binding protein (LBP) were upregulated in BRVO. Contactin-1 and alpha-enolase were downregulated in BRVO and correlated negatively with CRT.

Conclusions

Multiple proteins, including complement factors, fibrinogen chains, and apolipoprotein C-III, correlated with CRT, indicating a multifactorial response. Fibronectin correlated with BCVA, CRT, and VEGF. Fibronectin may reflect the severity of BRVO. The proinflammatory proteins CD14 and LBP were upregulated in BRVO.

Exhaled breath condensate in acute pulmonary embolism; a porcine study of effect of condensing temperature and feasibility of protein analysis by mass spectrometry

INTRODUCTION

The search for diagnostic biomarkers for pulmonary embolism (PE) has mainly been focused on blood samples. Exhaled breath condensate (EBC) is a possible source for biomarkers specific for chronic lung diseases and cancer, yet no previous studies have investigated the potential of EBC for diagnosis of PE. The protein content in the EBC is very low, and efficient condensing of the EBC is important in order to obtain high quality samples for protein analysis. We investigated if advanced proteomic techniques in a porcine model of acute intermediate-high-risk PE was feasible using two different condensing temperatures for EBC collection.

METHODS

Seven pigs were anaesthetized and intubated. EBC was collected one hour after intubation. Two autologous emboli were induced through the right external jugular vein. Two hours after the emboli were administered, EBC was collected again. Condensing temperature was either -21 °C or -80 °C. Nano liquid chromatography - tandem mass spectrometry (nLC-MS/MS) was used to identify and quantify proteins of the EBC.

RESULTS

A condensing temperature of - 80 °C significantly increased the EBC volume compared with -21 °C (1.78±0.25 ml vs 0.71±0.12 ml) while the protein concentration in the EBC was unaltered. The mean protein concentration in the EBCs was 5.85±0.93 µg/ml, unaltered after PE. In total, 254 proteins were identified in the EBCs. Identified proteins included proteins of the cytoplasm, nucleus, plasma membrane and extracellular region. The protein composition did not differ according to condensing temperature.

CONCLUSION

The EBC from pigs with acute intermediate-high-risk PE contained sufficient amounts of protein for analysis by nLC-MS/MS. The proteins were from relevant cellular compartments, indicating that EBC is a possible source for biomarkers for acute PE.

Biologic Therapy and Treatment Options in Diabetic Retinopathy with Diabetic Macular Edema

Proliferative diabetic retinopathy and diabetic macular edema can be a potentially sightthreatening disease if not treated correctly. It is directly correlated to the duration of diabetes and how well managed the patients' diabetes is. In the last 15 years, the treatment of diabetic eye disease has taken a quantum leap in methodology due to the group of biological agents named antivascular endothelial growth factor (anti-VEGF). The introduction of the first biological agent has revolutionized the treatment, not only in diabetic eye disease but also across most inflammatory eye diseases, causing leakage of fluid from the blood vessels i.e., in age-related macular degeneration. The availability of these biological agents, despite their considerable costs, have significantly improved the outcomes measured in visual acuity compared to more traditional treatments of diabetic retinopathy in the form of sole laser treatment and glycemic control. The agents demonstrate a favorable safety profile, but if the rarest and most severe side effects occur, there is a potential total loss of vision. This review aims to make an overview of the current pharmaceutical therapeutic options in the treatment of diabetic macular edema. This includes laser therapy, intravitreal steroids, and a primary focus on intravitreal antivascular endothelial growth factors.

SORLA Expression in Synaptic Plexiform Layers of Mouse Retina

Sorting protein-related receptor containing LDLR class A repeats (SORLA; also known as LR11) exerts intraneuronal trafficking functions in the central nervous system. Recently, involvement of SORLA in retinogenesis was proposed, but no studies have examined yet in detail the expression pattern of this sorting receptor in the retina. Here, we provide a spatio-temporal characterization of SORL1 mRNA and its translational product SORLA in the postnatal mouse retina. Using stereological analysis, we confirmed previous studies showing that receptor depletion in knockout mice significantly reduces the number of cells in the inner nuclear layer (INL), suggesting that functional SORLA expression is essential for the development of this retinal strata. qPCR and Western blot analyses showed that SORL1/SORLA expression peaks at postnatal day 15, just after eye opening. Interestingly, we found that transcripts are somatically located in several neuronal populations residing in the INL and the ganglion cell layer, whereas SORLA protein is also present in the synaptic plexiform layers. In line with receptor expression in dendritic terminals, we found delayed stratification of the inner plexiform layer in knockout mice, indicating an involvement of SORLA in neuronal connectivity. Altogether, these data suggest a novel role of SORLA in synaptogenesis. Receptor dysfunctions may be implicated in morphological and functional impairments of retinal inner layer formation associated with eye disorders.

Towards identification of novel putative biomarkers for infective endocarditis by serum proteomic analysis

INTRODUCTION

Infective endocarditis (IE) has high mortality, partly due to delayed diagnosis. No biomarker can identify IE in patients with fever and clinical picture of infection. To find putative biomarkers we analyzed serum levels of two proteins found in cardiac valves, fibulin-1 (n=696) and osteoprotegerin (n=689) among patients on clinical suspicion of IE. Proteomic analyses were performed in 24 patients with bacteremia, 12 patients with definite IE and 12 patients with excluded IE.

METHODS

Fibulin-1 and osteoprotegerin were studied by enzyme linked immunosorbent assay (ELISA). Proteomic analyses were conducted by 2-dimensional polyacrylamid gel electrophoresis (2D-PAGE) and label-free quantitative liquid chromatography - tandem mass spectrometry (LFQ LC-MS/MS). Controls for 2D 2D-PAGE and LFQ LC-MS/MS had bacteremia and excluded IE.

RESULTS

Osteoprotegerin levels were significantly increased in IE patients compared with non-IE patients. Fibulin-1 showed no difference. 2D-PAGE showed significant differences of 6 proteoforms: haptoglobin, haptoglobin-related protein, α-2-macroglobulin, apolipoprotein A-I and ficolin-3. LFQ LC-MS/MS analysis revealed significant level changes of 7 proteins: apolipoprotein L1, complement C1q subcomponent B and C, leukocyte immunoglobulin-like receptor subfamily A member 3, neuropilin-2, multimerin-1 and adiponectin.

CONCLUSIONS

The concentration changes in a set of proteoforms/proteins suggest that stress and inflammation responses are perturbed in patients with IE compared to patients with bacteremia without IE.

Animal Models Used to Simulate Retinal Artery Occlusion: A Comprehensive Review

Purpose

To present an overview of animal models of retinal artery occlusion (RAO).

Methods

Through a systematic literature search in PubMed and Embase, papers describing methods of inducing RAO in animal models were included. The identified methodologic approaches were presented in a narrative synthesis and compared with RAO in humans.

Results

In total, 83 papers reporting on 88 experiments were included. Six different species were used with rodents and monkeys being the most common, and a minority were performed using cats, dogs, rabbits, or pigs. The anatomy of pigs and monkeys resemble that of humans most closely. The two most frequently used methods were laser-induced occlusion or ligation of the arteries. Other methods included raised intraocular pressure, arterial clamping, administration of vasoconstricting agents, the use of an occluder, embolization, and endovascular approaches to induce occlusion. In general, occlusions lasted for only 30 to 90 minutes, often followed by reperfusion.

Conclusions

Although a broad range of methods have previously been used, they all have limitations. Preferably, the methods should imitate the human disease as closely as possible and avoid damaging other structures. Therefore, monkeys followed by pigs are to be preferred and ligation or clamping may be a suitable model in larger animals as there is a potential to isolate and occlude the retinal artery only. Being less invasive, laser-induced occlusion is another suitable approach.

Translational Relevance

This review aims at assisting researchers in deciding on the most ideal experimental setting, and thereby increase the translational value to human disease.

The serine protease HtrA1 cleaves misfolded transforming growth factor β-induced protein (TGFBIp) and induces amyloid formation

The serine protease high-temperature requirement protein A1 (HtrA1) is associated with protein-misfolding disorders such as Alzheimer's disease and transforming growth factor β-induced protein (TGFBIp)-linked corneal dystrophy. In this study, using several biochemical and biophysical approaches, including recombinant protein expression, LC-MS/MS and 2DE analyses, and thioflavin T (ThT) fluorescence assays for amyloid fibril detection, and FTIR assays, we investigated the role of HtrA1 both in normal TGFBIp turnover and in corneal amyloid formation. We show that HtrA1 can cleave WT TGFBIp but prefers amyloidogenic variants. Corneal TGFBIp is extensively processed in healthy people, resulting in C-terminal degradation products spanning the FAS1-4 domain of TGFBIp. We show here that HtrA1 cleaves the WT FAS1-4 domain only inefficiently, whereas the amyloidogenic FAS1-4 mutations transform this domain into a considerably better HTRA1 substrate. Moreover, HtrA1 cleavage of the mutant FAS1-4 domains generated peptides capable of forming in vitro amyloid aggregates. Significantly, these peptides have been previously identified in amyloid deposits in vivo, supporting the idea that HtrA1 is a causative agent for TGFBIp-associated amyloidosis in corneal dystrophy. In summary, our results indicate that TGFBIp is an HtrA1 substrate and that some mutations in the gene encoding TGFBIp cause aberrant HtrA1-mediated processing that results in amyloidogenesis in corneal dystrophies.

Brain spectroscopy reveals that N-acetylaspartate is associated to peripheral sensorimotor neuropathy in type 1 diabetes

AIMS

Emerging evidence shows, that distal symmetric peripheral neuropathy (DSPN) also involves alterations in the central nervous system. Hence, the aims were to investigate brain metabolites in white matter of adults with diabetes and DSPN, and to compare any cerebral disparities with peripheral nerve characteristics.

METHODS

In type 1 diabetes, brain metabolites of 47 adults with confirmed DSPN were compared with 28 matched healthy controls using proton magnetic resonance spectroscopy (H-MRS) in the parietal region including the sensorimotor fiber tracts.

RESULTS

Adults with diabetes had 9.3% lower ratio of N-acetylaspartate/creatine (NAA/cre) in comparison to healthy (p < 0.001). Lower NAA/cre was associated with lower sural (p = 0.01) and tibial (p = 0.04) nerve amplitudes, longer diabetes duration (p = 0.03) and higher age (p = 0.03). In addition, NAA/cre was significantly lower in the subgroup with proliferative retinopathy as compared to the subgroup with non-proliferative retinopathy (p = 0.02).

CONCLUSIONS

The association to peripheral nerve dysfunction, indicates concomitant presence of DSPN and central neuropathies, supporting the increasing recognition of diabetic neuropathy being, at least partly, a disease leading to polyneuropathy. Decreased NAA, is a potential promising biomarker of central neuronal dysfunction or loss, and thus may be useful to measure progression of neuropathy in diabetes or other neurodegenerative diseases.

Intravitreal bevacizumab upregulates transthyretin in experimental branch retinal vein occlusion

Purpose

To identify retinal protein changes that mediate beneficial effects of intravitreal bevacizumab in experimental branch retinal vein occlusion (BRVO).

Methods

In six Danish Landrace pigs, BRVO was induced with argon laser in both eyes. After BRVO was induced, the right eye of each animal was given an intravitreal injection of bevacizumab while the left eye was treated with saline water. The retinas were collected 15 days after BRVO, and differentially expressed proteins were analyzed with tandem mass tags-based mass spectrometry. Validation of statistically significantly changed proteins was performed with immunohistochemistry and western blotting.

Results

Fluorescein angiography showed no recanalization of the occluded vessels. A total of 4,013 proteins were successfully identified and quantified. Nine proteins were statistically significantly changed following bevacizumab intervention. In experimental BRVO, bevacizumab treatment resulted in upregulation of transthyretin (TTR) and pantothenate kinase 3. Bevacizumab downregulated protocadherin 7, protein FAM192A, and ATP synthase protein 8. Immunohistochemistry revealed that TTR was highly abundant in the choroid following bevacizumab intervention.

Conclusions

Bevacizumab intervention in experimental BRVO resulted in an increased level of TTR. This is the second study in which we showed an increased retinal level of TTR following anti-vascular endothelial growth factor (VEGF) intervention in experimental BRVO. We hypothesize that there is an interaction between TTR and VEGF and that bevacizumab may exert a beneficial effect on the retina by upregulating TTR.

Pulmonary safety of ophthalmic beta-blockers: a nationwide registry-based cohort study

PURPOSE

Ophthalmic beta-blockers, used in the treatment of increased intraocular pressure, are known to cause pulmonary adverse effects. Few, if any, studies have quantified the extent of the problem in a real-life population. In this nationwide study, we assess the pulmonary safety of patients initiating treatment with ophthalmic beta-blockers.

METHODS

Using the Danish Nationwide Registries from 1995 to 2012, we identified all individuals aged 20-90 years who initiated monotherapy with an intraocular pressure-lowering drug, with or without concomitant obstructive pulmonary disease. Risks of (i) switching to another drug and (ii) new onset of obstructive pulmonary disease during a 90-day follow-up were examined by cumulative risk and logistic regression models adjusted for available covariates.

RESULTS

The cohort consisted of 97 463 individuals. Odds ratios for drug switch in individuals without concomitant obstructive pulmonary disease (n = 86 568) were as follows: 1.47 for beta-blockers (95% confidence interval (CI): 1.35-1.61; p < 0.001), 2.68 for parasympathomimetics (95% CI: 2.32-3.10; p < 0.001) and 4.80 for alfa-2-agonists (95% CI: 4.17-5.53; p < 0.001). Odds ratios in individuals with concomitant obstructive pulmonary disease (n = 10 895) were as follows: 2.61 for parasympathomimetics (95% CI: 1.83-3.72; p < 0.001), 2.96 for beta-blockers (95% CI: 2.31-3.78; p < 0.001) and 3.54 for alfa-2-agonists (95% CI: 2.56-4.88; p < 0.001). There was no significant association between treatment class and new onset of obstructive pulmonary disease (p = 0.30).

CONCLUSION

Ophthalmic beta-blockers were associated with an increased risk of drug switch. However, the absolute risk was very small. No increased risk of new onset of obstructive pulmonary disease was found. Our data suggest that more patients might be eligible for ophthalmic beta-blockers.

IL-18 and S100A12 Are Upregulated in Experimental Central Retinal Vein Occlusion

Retinal vein occlusion (RVO) is a common retinal vascular disease. RVO may be complicated by pronounced ischemia that often leads to severe loss of visual function. The present work aimed at studying the retinal proteome of RVO complicated by ischemia. In six Danish Landrace pigs RVO was induced with argon laser in the right eye of each animal. As four retinal veins were occluded, the RVO best corresponded to a central retinal vein occlusion (CRVO). Left control eyes received a similar laser treatment without inducing occlusion. RVO and retinal ischemia were verified by angiography. The retinas were collected 15 days after RVO for proteomic analysis. RVO resulted in a downregulation of proteins involved in visual perception, including rhodopsin, transducin alpha chain, and peripherin-2. RVO also caused a downregulation of proteins involved in neurotransmitter transport, including glutamate decarboxylase 1 (GAD1), glutamate decarboxylase 2 (GAD2), and complexins 2⁻4. RVO lead to increased contents of proteins involved in inflammation, including interleukin-18 (IL-18), S100A12, and annexin A1 (ANXA1). Immunohistochemistry revealed a general retinal upregulation of IL-18 and ANXA1 while S100A12 was highly abundant in retinal ganglion cells in RVO. IL-18 and S100A12 are likely to be driving forces in the inflammatory response of RVO complicated by ischemia. Our findings also suggest that RVO results in compromised neurotransmission and a downregulation of proteins involved in visual perception.

Dexamethasone intravitreal implant downregulates PDGFR-α and upregulates caveolin-1 in experimental branch retinal vein occlusion

A dexamethasone (DEX) intravitreal implant (OZURDEX) provides an effective treatment of inflammation secondary to branch retinal vein occlusion (BRVO). Retinal proteome changes which mediate the beneficial effects of the implant remain poorly understood. To study retinal proteome changes in BRVO following an intervention with a DEX implant this study combined an experimental model of BRVO with proteomic techniques. In eight Danish Landrace pigs experimental BRVO was induced in both eyes using argon laser. After inducing BRVO a DEX implant was injected into the right eye of each animal while the left control eye was given an identical injection without an implant. Fifteen days after BRVO and DEX implant intervention the retinas were excised and analyzed with tandem mass tag based mass spectrometry. A total of 26 significantly changed proteins were identified. DEX intervention reduced the retinal levels of platelet-derived growth factor receptor-α (PDGFR-α) and vascular endothelial growth factor receptor 2 (VEGFR-2). DEX treatment resulted in increased levels of caveolin-1, peptidyl-prolyl cis-trans isomerase FKBP5 and transgelin. Changes in PDGFR-α and caveolin-1 were confirmed with immunohistochemistry. In BRVO treated with the DEX implant a strong reaction for caveolin-1 was observed in the innermost retinal layers. DEX implant intervention may inhibit PDGF signaling by decreasing the retinal level of PDGFR-α while an increased content of caveolin-1 may help maintain the integrity of the blood-retinal barrier.

Functional benefits and patient satisfaction with upper blepharoplasty - evaluated by objective and subjective outcome measures

PURPOSE

To investigate the functional benefits and patient satisfaction with upper blepharoplasty in patients meeting the Danish visitation guidelines for upper blepharoplasty from the Danish Health and Medicines Authority (Sundhedsstyrelsen).

METHODS

Before and 3 months after upper blepharoplasty, the following investigations were made: (i) a standard eye examination, (ii) photographic documentation with a normal camera and the infrared camera of a Spectralis Optical Coherence Tomograph and (iii) measurements of the upper visual fields using the blepharoptosis test of Octopus 900. Along with the pre- and postoperative examinations, the patients completed a questionnaire concerning the functional and psychosocial impact of their eyelids.

RESULTS

Ninety eyelids of 45 patients were studied, 34 females and 11 males. The mean age was 56.9 years (SD: 12.8). The mean change in the distance between the upper eyelid skin fold and the visual axis or the marginal reflex distance (MRD), depending on which was lowest, was 1.6 mm (SD: 0.8 mm) for the right eyelids and 1.2 (SD: 0.9 mm) for the left eyelids. The mean improvement in the upper visual field was 31.3% points for the right eyelids (SD: 21.4% points) and 28.3% points for the left eyelids (SD: 24.9% points). A statistically significant correlation between the preoperative distance from skin fold to visual axis/MRD and the pre- and postoperative visual field was found. The patients reported an improvement in their symptoms postoperatively. All subjects were satisfied with the postoperative result and would undergo the surgery again if they had to make the choice again.

CONCLUSION

Patients meeting the Danish visitation guidelines for upper blepharoplasty experience a measurable improvement in function and alleviation of symptoms after blepharoplasty.

Proteomic profiling of TGFBI-null mouse corneas reveals only minor changes in matrix composition supportive of TGFBI knockdown as therapy against TGFBI-linked corneal dystrophies

TGFBIp is a constituent of the extracellular matrix in many human tissues including the cornea, where it is one of the most abundant proteins expressed. TGFBIp interacts with Type I, II, IV, VI, and XII collagens as well as several members of the integrin family, suggesting it plays an important role in maintaining structural integrity and possibly corneal transparency as well. Significantly, more than 60 point mutations within the TGFBI gene have been reported to result in aberrant TGFBIp folding and aggregation in the cornea, resulting in severe visual impairment and blindness. Several studies have focused on targeting TGFBIp in the cornea as a therapeutic approach to treat TGFBI-linked corneal dystrophies, but the effect of this approach on corneal homeostasis and matrix integrity remained unknown. In the current study, we evaluated the histological and proteomic profiles of corneas from TGFBI-deficient mice as well as potential redundant functions of the paralogous protein POSTN. The absence of TGFBIp in mouse corneas did not grossly affect the collagen scaffold, and POSTN is unable to compensate for loss of TGFBIp. Proteomic comparison of wild-type and TGFBI^-/- mice revealed 11 proteins were differentially regulated, including Type VI and XII collagens. However, as these alterations did not manifest at the macroscopic and behavioral levels, these data support partial or complete TGFBI knockdown as a potential therapy against TGFBI-linked corneal dystrophies. Lastly, in situ hybridization verified TGFBI mRNA in the epithelial cells but not in other cell types, supportive of a therapy directed specifically at this lineage.

Diurnal expression of proteins in the retina of the blind cone-rod homeobox (Crx-/- ) mouse and the 129/Sv mouse: a proteomic study

PURPOSE

The vertebrate retina contains a circadian clock participating in adaptations to day and night vision. This peripheral clock is independent of the master clock in the suprachiasmatic nucleus (SCN). The retinal clock is located in several cell types, including the photoreceptors. To investigate the role of the circadian clock of the photoreceptor cells in regulation of retinal protein rhythms, we analysed diurnal protein expression in the photoreceptor-deficient cone-rod homeobox knockout mouse (Crx^-/- ) and the 129/Sv mouse.

METHODS

2D gels were made from retinal homogenates of 129/Sv and Crx^-/- mice killed at midday and midnight. Stained gels were analysed by use of PDQuest 2D gel analysis software. After trypsin digestion of differential expressed spots, the proteins were identified by LC-MS/MS using a nano-liquid chromatograph connected to a Q-TOF Premier mass spectrometer. These data were used to search the SWISS-PROT database.

RESULTS

Both the retinae of the control and the Crx^-/- mice exhibited diurnal proteins rhythms. As expected, proteins involved in phototransduction were not detected in the Crx^-/- mouse; in this phenotype, however, proteins from spots showing diurnal rhythms were specifically identified as enzymes involved in glucose metabolism, Krebs cycle, and mitochondrial enzymes. Data are available via ProteomeXchange with identifier PXD005556.

CONCLUSION

We show diurnal protein rhythms in the retina of a mouse lacking the rods and cones. The diurnal protein rhythms in this genotype, lacking the circadian clock of the photoreceptors, might be caused by a circadian clock in other retinal cell types or a direct light input to the retina.