Is vitamin D deficiency associated with retinopathy in type 2 diabetes mellitus? A case-control study

BACKGROUND AND AIMS

This study aimed to determine the associations between vitamin D deficiency and diabetic retinopathy (DR) progression risk in type 2 diabetes mellitus (T2DM) patients.

METHODS

This is a case-control study that enrolled 201 diabetic retinopathy (DR) patients as case and 201 T2DM without DR as a control. Demographic variables were obtained during an interview using a questionnaire, furthermore, anthropometric measures were evaluated based on the standard protocol. In addition, biochemical indices including 25-hydroxyvitamin D, fasting blood glucose (FBG), insulin, Glycosylated hemoglobin (HbA1c), total cholesterol (TC), LDL-C, HDL-C, and triglyceride (TG) were assessed for all of the participants. Multivariate logistic regression was performed to estimate the relationship between vitamin D and retinopathy.

RESULTS

Based on the statistical analysis of age, sex, and BMI there was no significant difference between the two groups, while the mean concentration of 25-hydroxyvitamin D substantially was lower in case group in comparison with the control group (14.46 VS. 19.88). Furthermore, low levels of vitamin D are associated with DR and consequently proliferative diabetic retinopathy (PDR) in patients with T2DM.

CONCLUSION

Totally based on the results of the present study vitamin D deficiency increased the risk of RD in patients with T2DM, also in case of deficiency of this nutrient, retinopathy may develop into PDR type.

THE IMPACT OF TOTAL PHYSICAL ACTIVITY ON MICROVASCULAR COMPLICATIONS IN TYPE 1 DIABETES MELLITUS PATIENTS

The incidence of diabetes is increasing worldwide, emphasizing an emerging need for blood glucose control optimization to prevent the development of chronic complications and improve the quality of life. This retrospective cohort study aimed to investigate the effects of total physical activity on microvascular diabetic complication development in patients with type 1 diabetes mellitus (T1DM). The study included 71 T1DM patients, average age 41 years and HbA1c 7.78%. Most patients (82.1%) reported having hypoglycemia, while the minority of patients developed microvascular complications, mostly nonproliferative retinopathy (17.7%). All subjects included in the study were moderately or vigorously physically active. No association was observed between total physical activity and regulation of glycemia, hypoglycemic incidents, or development of microvascular complications. Until sufficient data from prospective studies become available, our data support the findings of no negative effect of higher intensity physical activity on the development of microvascular complications in T1DM patients.

Triciribine attenuates pathological neovascularization and vascular permeability in a mouse model of proliferative retinopathy

Proliferative retinopathies are the leading cause of irreversible blindness in all ages, and there is a critical need to identify novel therapies. We investigated the impact of triciribine (TCBN), a tricyclic nucleoside analog and a weak Akt inhibitor, on retinal neurovascular injury, vascular permeability, and inflammation in oxygen-induced retinopathy (OIR). Post-natal day 7 (P7) mouse pups were subjected to OIR, and treated (i.p.) with TCBN or vehicle from P14-P16 and compared with age-matched, normoxic, vehicle or TCBN-treated controls. P17 retinas were processed for flat mounts, immunostaining, Western blotting, and qRT-PCR studies. Fluorescein angiography, electroretinography, and spectral domain optical coherence tomography were performed on days P21, P26, and P30, respectively. TCBN treatment significantly reduced pathological neovascularization, vaso-obliteration, and inflammation marked by reduced TNFα, IL6, MCP-1, Iba1, and F4/80 (macrophage/microglia markers) expression compared to the vehicle-treated OIR mouse retinas. Pathological expression of VEGF (vascular endothelial growth factor), and claudin-5 compromised the blood-retinal barrier integrity in the OIR retinas correlating with increased vascular permeability and neovascular tuft formation, which were blunted by TCBN treatment. Of note, there were no changes in the retinal architecture or retinal cell function in response to TCBN in the normoxia or OIR mice. We conclude that TCBN protects against pathological neovascularization, restores blood-retinal barrier homeostasis, and reduces retinal inflammation without adversely affecting the retinal structure and neuronal function in a mouse model of OIR. Our data suggest that TCBN may provide a novel therapeutic option for proliferative retinopathy.

Hypertension: A Cause of Bilateral Proliferative Retinopathy

Purpose

To describe the case of a 67-year-old female with proliferative retinopathy secondary to uncontrolled hypertension.

Methods

Retrospective case report including multimodal imaging.

Results

A 67-year-old female presented with mild vitreous hemorrhage, retinal hemorrhage, hard exudate of the left eye and hard exudate, copper wiring of vessels, and retinal hemorrhages in the right eye. Optical coherence tomography depicted macular edema of both eyes. Fluorescein angiography revealed large areas of peripheral retinal ischemia and neovascularization with multiple areas of vascular leakage in both eyes.

Conclusions

Proliferative hypertensive retinopathy has been rarely reported in the literature. Our patient exhibited findings consistent with proliferative retinopathy secondary to hypertensive retinopathy.

Sphingosine-1-phosphate and ceramide-1-phosphate promote migration, pro-inflammatory and pro-fibrotic responses in retinal pigment epithelium cells

Retinal pigment epithelium (RPE) cells, essential for preserving retina homeostasis, also contribute to the development of retina proliferative diseases, through their exacerbated migration, epithelial to mesenchymal transition (EMT) and inflammatory response. Uncovering the mechanisms inducing these changes is crucial for designing effective treatments for these pathologies. Sphingosine-1-phosphate (S1P) and ceramide-1-phosphate (C1P) are bioactive sphingolipids that promote migration and inflammation in several cell types; we recently established that they stimulate the migration of retina Müller glial cells (Simón et al., 2015; Vera et al., 2021). We here analyzed whether S1P and C1P regulate migration, inflammation and EMT in RPE cells. We cultured two human RPE cell lines, ARPE-19 and D407 cells, and supplemented them with either 5 μM S1P or 10 μM C1P, or their vehicles, for 24 h. Analysis of cell migration by the scratch wound assay showed that S1P addition significantly enhanced migration in both cell lines. Pre-treatment with W146 and BML-241, antagonists for S1P receptor 1 (S1P1) and 3 (S1P3), respectively, blocked exogenous S1P-induced migration. Inhibiting sphingosine kinase 1 (SphK1), the enzyme involved in S1P synthesis, significantly reduced cell migration and exogenous S1P only partially restored it. Addition of C1P markedly stimulated cell migration. Whereas inhibiting C1P synthesis did not affect C1P-induced migration, inhibiting S1P synthesis strikingly decreased it; noteworthy, addition of C1P promoted the transcription of SphK1. These results suggest that S1P and C1P stimulate RPE cell migration and their effect requires S1P endogenous synthesis. Both S1P and C1P increase the transcription of pro-inflammatory cytokines IL-6 and IL-8, and of EMT marker α-smooth muscle actin (α-SMA) in ARPE-19 cells. Collectively, our results suggest new roles for S1P and C1P in the regulation of RPE cell migration and inflammation; since the deregulation of sphingolipid metabolism is involved in several proliferative retinopathies, targeting their metabolism might provide new tools for treating these pathologies.

The role of growth hormone and IGF-1 in retinopathy: a prospective study of retinopathy in patients with acromegaly and impaired fasting glucose

AIMS

To investigate the effects of the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis on the incidence and progression of retinopathy.

METHODS

We enrolled 91 patients with acromegaly and 123 subjects with impaired fasting glucose (IFG) between 2008 and 2016 to examine the incidence and prevalence of retinopathy. Patients attended follow-ups in our clinics and underwent examinations according to the national guidelines for diabetes management. Both cohorts attended follow-ups until June 2019.

RESULTS

Both groups had similar HbA1c, cholesterol, and blood pressure levels. However, patients with acromegaly had higher GH (8.05 ± 16.18 vs. 0.78 ± 1.25 ng/mL) and IGF-1 (547.0 ± 342.1 vs. 146.7 ± 51.4 ng/mL) levels than in subjects with IFG. During the follow-up period, 8 patients (8.8%) with acromegaly and 12 patients (9.8%) with IFG developed some degree of retinopathy. Three patients with acromegaly and two with IFG progressed to proliferative retinopathy. Patients with acromegaly had the same incidence of non-proliferative retinopathy (odds ratio [OR] 0.830; 95% CI 0.318-2.164) and a non-statistically significantly higher incidence of proliferative retinopathy (OR 2.461; 95% CI 0.404-14.988).

CONCLUSION

The data reveals that GH and IGF-1 might play a crucial role in the development of proliferative retinopathy and influence its progression. Therefore, we suggest screening patients with acromegaly should be similar to diabetes patients.

Hypertension as an Unusual Cause of Proliferative Retinopathy: Case Report and Literature Review

Malignant hypertensive retinopathy is associated with characteristic fundus findings that typically do not include proliferative retinal vascular changes. We present the case of a 34-year-old patient who had bilateral decreased vision and was found to have malignant hypertension with hypertensive retinopathy changes along with unforeseen bilateral neovascularization and vitreous hemorrhage. Detailed history and extensive systemic and ophthalmic workup failed to reveal an alternative explanation for her proliferative retinopathy. Blood pressure control and panretinal photocoagulation halted further deterioration. Malignant hypertensive retinopathy can rarely cause profound retinal ischemia leading to retinal neovascularization. This case further supports the presence of "proliferative hypertensive retinopathy" that needs to be identified and addressed urgently through collaboration between internists and ophthalmologists.

Proliferative retinopathy as a feature of Vogt Koyanagi Harada Disease: a report of two cases

BACKGROUND

Proliferative retinopathy is an uncommon feature of Vogt Koyanagi Harada (VKH) disease which might indicate poor uveitis control in these patients. We aim to describe the clinical features and outcome of management of proliferative retinopathy in 2 patients with VKH.

CASE PRESENTATION

19 and 33 years old females with VKH presented with unilateral proliferative retinopathy. Both patients had neovascularization of the optic disc (NVDs) and one patient had neovascularizations elsewhere (NVEs) and preretinal hemorrhage. Both patients had exudative retinal detachments (ERD). Systemic steroids and immunomodulatory agents were successfully used to control inflammation and achieve regression. One patient developed fibrous tissue formation at the disc area as well as an epiretinal membrane formation, for which she had pars plana vitrectomy with membrane peeling. Both patients had controlled inflammation with stable vision.

CONCLUSIONS

Proliferative retinopathy can present variably in VKH patients and indicates persistent inflammation which is incompletely controlled. Proper uveitis control is sufficient to achieve regression of retinal neovascularization.

Progressive Preretinal Fibrosis with Late, Ossifying, Proliferative Retinopathy following Treatment for Retinoblastoma

We report a case of retinal atrophy and progressive preretinal fibrosis in an eye previously treated with intravenous and intra-arterial chemotherapy (IAC), which evolved immediately after treatment with intravitreal injection of melphalan. The atrophy and fibrosis progressed later to proliferative retinopathy with dystrophic ossification. The patient was originally diagnosed with bilateral retinoblastoma at 4 months of age and was treated with systemic chemotherapy followed by IAC. New vitreous seeds developed and required treatment with intravitreal chemotherapy. There was resolution of vitreous seeding after 2 doses of intravitreal melphalan, but clinically the eye developed new, widespread retinal atrophy and fibrosis within 1 month of the second injection. This was followed by phthisis and late proliferative retinopathy nearly 1 year later. Retinoblastoma specialists should be aware of this potential complication of combined chemotherapy treatments.

Gaining insight on mitigation of rubeosis iridis by UPARANT in a mouse model associated with proliferative retinopathy

Proliferative retinopathies (PR) lead to an increase in neovascularization and inflammation factors, at times culminating in pathologic rubeosis iridis (RI). In mice, uveal puncture combined with injection of hypoxia-conditioned media mimics RI associated with proliferative retinopathies. Here, we investigated the effects of the urokinase plasminogen activator receptor (uPAR) antagonist-UPARANT-on the angiogenic and inflammatory processes that are dysregulated in this model. In addition, the effects of UPARANT were compared with those of anti-vascular endothelial growth factor (VEGF) therapies. Administration of UPARANT promptly decreased iris vasculature, while anti-VEGF effects were slower and less pronounced. Immunoblot and qPCR analysis suggested that UPARANT acts predominantly by reducing the upregulated inflammatory and extracellular matrix degradation responses. UPARANT appears to be more effective in comparison to anti-VEGF in the treatment of RI associated with PR in the murine model, by modulating multiple uPAR-associated signaling pathways. Furthermore, UPARANT effectiveness was maintained when systemically administered, which could open to novel improved therapies for proliferative ocular diseases, particularly those associated with PR. KEY MESSAGES: • Further evidence of UPARANT effectiveness in normalizing pathological iris neovascularization. • Both systemic and local administration of UPARANT reduce iris neovascularization in a model associated with proliferative retinopathies. • In the mouse models of rubeosis iridis associated with proliferative retinopathy, UPARANT displays stronger effects when compared with anti-vascular endothelial growth factor regimen.

SCREENING FOR DIABETIC RETINOPATHY - A TWELVE-MONTH REVIEW

The purpose is to provide a twelve-month database review of screening for diabetic retinopathy (DR). A total of 1428 diabetes mellitus (DM) patients screened in 2017 were analyzed in a retrospective study. Retinal photographs were reviewed by an ophthalmologist for the presence and stage of DR, as well as for additional nondiabetic findings. The following grading categories of DR were used: without DR, mild non-proliferative DR (NPDR), moderate NPDR, severe non-proliferative NPDR, proliferative DR (PDR), clinically significant macular edema (CSME) and ungradable finding. Severe NPDR, PDR and CSME were classified as vision-threatening DR. Out of 1428 DM patients, 27 were diagnosed with type 1 DM and 1401 with type 2 DM, 353 of them had newly diagnosed type 2 DM. Without DR category was recorded in 85.2% of all eyes screened, 2.8% were ungradable, and 12% showed varying stages of DR. Vision-threatening DR was found in 2.8% and additional nondiabetic findings in 5.2% of all screened eyes. In the group of newly diagnosed type 2 DM, 92.5% of screened eyes were without DR, 3.1% were ungradable and 4.3% showed varying stages of DR. In the group of newly diagnosed type 2 DM, vision-threatening DR was recorded in 0.1% and additional nondiabetic finding in 5.7% of the eyes screened. In conclusion, a small proportion of screened DM patients with detected DR had vision-threatening DR.

Hyperglycaemia as a risk factor for the development of retinopathy of prematurity: A cohort study

BACKGROUND

Retinopathy of prematurity (ROP) is a preventable cause of childhood blindness. Without treatment, over 45% of eyes can develop permanent visual loss. Hyperglycaemia has recently been described as a risk factor for the development of retinopathy of prematurity (ROP), a proliferative vascular disease of the retina that primarily affects premature infants. The characteristic neoproliferative growth of blood vessels in the retina is very well under stood with the clinical and experimental experiences with Diabetic retinopathy. The purpose of this study was to evaluate a possible relation between glucose levels in VLBW (Very Low Birth Weight) infants and development of ROP.

METHOD

All at risk infants of a Neonatal Intensive Care Unit (NICU) of a tertiary care centre in western India were included in the study. The blood sugar values of the neonates were recorded at multiple times during their first week of life. On completion of 31 weeks of gestational age or 04 weeks of birth age, the neonates were subjected to ROP screening as per standard protocols.

RESULT

A total of 103 neonates were included in the study and were subjected to ROP screening. A total of 32 neonates developed ROP at the end of the study. It was found with statistical significance that the neonates with higher average blood glucose values in the initial period of life had higher incidence of ROP at the time of screening with a Relative Risk of 2.506 (CI = 1.287, 4.882).

CONCLUSION

A high average blood glucose level in neonates during the first week of life is an indicator for developing ROP at a later date. These neonates should be kept under close follow up in order to facilitate timely detection and prompt intervention.

Chronic myeloid leukaemia accelerates proliferative retinopathy in patients with co-existent diabetes: A risk factor not to be ignored

OBJECTIVE

To describe the retinal imaging characteristics, retinopathy management strategies and visual outcomes in cases of diabetes with chronic myeloid leukaemia.

DESIGN

Retrospective observational study.

PARTICIPANTS

Patients with diabetes and chronic myeloid leukaemia managed at our tertiary eye care centre from January 2015 to December 2017.

METHODS

Detailed ophthalmic and systemic evaluation, treatment and follow-up records were reviewed. The main measures studied were visual acuity, intra-ocular pressure, retinopathy severity, and surgical indications and techniques.

RESULTS

Of the six patients studied, three had diabetes and chronic myeloid leukaemia at presentation, while in three cases chronic myeloid leukaemia was diagnosed following evaluation for proliferative retinopathy. The visual acuity ranged from 20/20 to perception of light. All eyes had marked proliferative retinopathy out of proportion to the exudation. None of the eyes had significant macular oedema. Pan-retinal photocoagulation (10/12, 83.33%), intravitreal anti-vascular endothelial growth factor injection (8/12, 66.67%), vitrectomy (2/12, 16.67%), cataract surgery (2/12, 16.67%) and trabeculectomy followed by cryoablation (2/12, 16.67%) was performed for management of the ocular disease as indicated. Median follow-up was 16.5 months (range: 6-24 months). Final visual acuity ranged from PL to 20/20 with acuity ⩾ 20/100 in eight eyes. Four eyes had advanced optic neuropathy from neovascular glaucoma.

CONCLUSION

Accelerated proliferative retinopathy can be seen in cases of diabetes with chronic myeloid leukaemia at the very initial ophthalmic evaluation. Thus, there is a need to alter screening guidelines for retinopathy in cases of diabetes with chronic myeloid leukaemia. Early detection and aggressive management may help preserve visual acuity in such cases.

Human vitreous in proliferative diabetic retinopathy: Characterization and translational implications

Diabetic retinopathy (DR) is one of the leading causes of visual impairment in the working-age population. DR is a progressive eye disease caused by long-term accumulation of hyperglycaemia-mediated pathological alterations in the retina of diabetic patients. DR begins with asymptomatic retinal abnormalities and may progress to advanced-stage proliferative diabetic retinopathy (PDR), characterized by neovascularization or preretinal/vitreous haemorrhages. The vitreous, a transparent gel that fills the posterior cavity of the eye, plays a vital role in maintaining ocular function. Structural and molecular alterations of the vitreous, observed during DR progression, are consequences of metabolic and functional modifications of the retinal tissue. Thus, vitreal alterations reflect the pathological events occurring at the vitreoretinal interface. These events are caused by hypoxic, oxidative, inflammatory, neurodegenerative, and leukostatic conditions that occur during diabetes. Conversely, PDR vitreous can exert pathological effects on the diabetic retina, resulting in activation of a vicious cycle that contributes to disease progression. In this review, we recapitulate the major pathological features of DR/PDR, and focus on the structural and molecular changes that characterize the vitreal structure and composition during DR and progression to PDR. In PDR, vitreous represents a reservoir of pathological signalling molecules. Therefore, in this review we discuss how studying the biological activity of the vitreous in different in vitro, ex vivo, and in vivo experimental models can provide insights into the pathogenesis of PDR. In addition, the vitreous from PDR patients can represent a novel tool to obtain preclinical experimental evidences for the development and characterization of new therapeutic drug candidates for PDR therapy.

Secondary hyperhomocysteinemia-related occlusive retinal vasculopathy: A case report

PURPOSE

To report a case of occlusive retinal vasculopathy, secondary to hyperhomocysteinemia.

OBSERVATIONS

A 43-year-old male was examined at the retina outpatient clinic due to complaints of bilateral decrease in visual acuity. The patient underwent a comprehensive ophthalmological examination, wide-field fundus photographs and fluorescein angiography, as well as spectral domain optical coherence tomography with enhanced-deep imaging. The patient had a significant medical history of chronic kidney disease and progressive bilateral vision loss over the last two years, which worsened in the left eye during the past 3 months. Fundus examination revealed a vitreous hemorrhage in the left eye and bilateral proliferative retinopathy. Blood glucose and systemic blood pressure were unremarkable. Plasma homocysteine was reported at >500 μmol/L, which is higher than the corrected reference range by age.

CONCLUSION AND IMPORTANCE

Hyperhomocysteinemia is a rare but well-known disease, capable of accelerating atherosclerotic disease and generating a prothrombotic state that can lead to multiple systemic complications. Despite its low incidence, the disease should be part of the differential diagnosis in patients with bilateral proliferative retinopathy, in the absence of diabetes mellitus and systemic hypertension.

Update of inflammatory proliferative retinopathy: Ischemia, hypoxia and angiogenesis

Diabetic retinopathy (DR) and retinopathy of prematurity (ROP) present two examples of proliferative retinopathy, characterized by the same stages of progression; ischemia of the retinal vessels, leads to hypoxia and to correct the problem there is the setting up of uncontrolled angiogenesis, which subsequently causes blindness or even detachment of the retina. The difference is the following; that DR initiated by the metabolic complications that are due to hyperglycemia, and ROP is induced by overexposure of the neonatal retina to oxygen. In this review, we will demonstrate the physiopathological mechanism of the two forms of proliferative retinopathy DR and ROP, in particular the role of the CD40/CD40L axis and IL-1 on vascular complications and onset of inflammation of the retina, the implications of their effects on the onset of pathogenic angiogenesis, thus understanding the link between platelets and retinal ischemia. In addition, what are the therapeutic targets that could slow its progression?

Anti-angiogenic effects of the DPP-4 inhibitor linagliptin via inhibition of VEGFR signalling in the mouse model of oxygen-induced retinopathy

AIMS/HYPOTHESIS

Linagliptin has protective effects on the retinal neurovascular unit but, in proliferative retinopathy, dipeptidyl peptidase 4 (DPP-4) inhibition could be detrimental. The aim of this study was to assess the effect of linagliptin on ischaemia-induced neovascularisation of the retina.

METHODS

C57BL/6J and glucagon-like peptide 1 (GLP-1) receptor (Glp1r)^-/- mice were subjected to a model of oxygen-induced retinopathy (OIR). Both strains were subcutaneously treated with linagliptin from postnatal days 12 to 16. Non-injected OIR and non-exposed mice served as controls. Capillary proliferations and systemic levels of active GLP-1 were quantified. The effects of linagliptin on vascular endothelial growth factor (VEGF)-induced downstream signalling were assessed in human umbilical vein endothelial cells (HUVECs) using western blot for retinal phosphorylated extracellular signal-regulated kinase (ERK)1/2 and retinal gene expression analyses.

RESULTS

Linagliptin treatment led to an increase in active GLP-1 and a decreased number of neovascular nuclei in OIR mice vs controls (-30%, p < 0.05). As the reduction in neovascularisation was similar in both C57BL/6J and Glp1r^-/- mice, the anti-angiogenic effects of linagliptin were independent of GLP-1R status. The expression of Vegf (also known as Vegfa) and Hif1a was increased in C57BL/6J OIR mice upon linagliptin treatment (three- vs 1.5-fold, p < 0.05, p < 0.01, respectively). In HUVECs, linagliptin inhibited VEGF-induced increases in mitogen-activated protein kinase (MAPK)/ERK (-67%, p < 0.001) and MAPK/c-Jun N-terminal kinase (JNK) (-13%, p < 0.05) pathway activities. In the retinas of C57BL/6J mice, p-ERK1/2 levels were significantly reduced upon linagliptin treatment (-47%, p < 0.05).

CONCLUSIONS/INTERPRETATION

Systemic treatment with linagliptin demonstrated GLP-1R-independent anti-angiogenic effects mediated by an inhibition of VEGF receptor downstream signalling. The specific effects of linagliptin on diabetic retinopathy are of potential benefit for individuals with diabetes, independent of metabolic effects.

Increased prevalence of proliferative retinopathy in patients with acromegaly

BACKGROUND

This pilot study was carried to determine the prevalence of retinopathy, especially proliferative retinopathy, in patients with acromegaly.

METHODS

We analyzed 43 acromegalic patients and 129 age- and gender-matched patients with type 2 diabetes. The retinopathy status was determined from the medical records based on the ophthalmologist consultations of patients with acromegaly. Color photographs of the macula- and disc-centered views were obtained at an angle of 45° with a fundus camera after pharmacologic-induced mydriasis in patients with type 2 diabetes.

RESULTS

Compared with age- and gender-matched patients with type 2 diabetes, the acromegalic patients had lower fasting plasma glucose levels and lower systolic and diastolic blood pressures, but were taller and had higher IGF-1 levels. Any degree of retinopathy was present in 9.3% (4 of 43) of patients with acromegaly and 34.9% (45 of 129) of patients with type 2 diabetes (odds ratio [OR] = 0.191; 95% confidence interval [CI] = 0.064-0.570). Proliferative retinopathy was present in 9.3% (4 of 43) of patients with acromegaly and 9.3% (12 of 129) of patients with type 2 diabetes (OR = 1.000; 95% CI = 0.305-3.281). Non-proliferative retinopathy was absent in patients with acromegaly, but present in 25.9% (33 of 129) of patients with type 2 diabetes.

CONCLUSION

The high proliferative, but absence of non-proliferative retinopathy in our patients with acromegaly may reflect the pathogenic effect of IGF-1 on neovascularization. IGF-1 may play an important role in proliferative retinopathy, but may play no role in non-proliferative retinopathy.

Study protocol: safety and efficacy of propranolol 0.2% eye drops in newborns with a precocious stage of retinopathy of prematurity (DROP-ROP-0.2%): a multicenter, open-label, single arm, phase II trial

BACKGROUND

Retinopathy of prematurity (ROP) still represents one of the leading causes of visual impairment in childhood. Systemic propranolol has proven to be effective in reducing ROP progression in preterm newborns, although safety was not sufficiently guaranteed. On the contrary, topical treatment with propranolol eye micro-drops at a concentration of 0.1% had an optimal safety profile in preterm newborns with ROP, but was not sufficiently effective in reducing the disease progression if administered at an advanced stage (during stage 2). The aim of the present protocol is to evaluate the safety and efficacy of propranolol 0.2% eye micro-drops in preterm newborns at a more precocious stage of ROP (stage 1).

METHODS

A multicenter, open-label, phase II, clinical trial, planned according to the Simon optimal two-stage design, will be performed to analyze the safety and efficacy of propranolol 0.2% eye micro-drops in preterm newborns with stage 1 ROP. Preterm newborns with a gestational age of 23-32 weeks, with a stage 1 ROP will receive propranolol 0.2% eye micro-drops treatment until retinal vascularization has been completed, but for no longer than 90 days. Hemodynamic and respiratory parameters will be continuously monitored. Blood samplings checking metabolic, renal and liver functions, as well as electrocardiogram and echocardiogram, will be periodically performed to investigate treatment safety. Additionally, propranolol plasma levels will be measured at the steady state, on the 10th day of treatment. To assess the efficacy of topical treatment, the ROP progression from stage 1 ROP to stage 2 or 3 with plus will be evaluated by serial ophthalmologic examinations.

DISCUSSION

Propranolol eye micro-drops could represent an ideal strategy in counteracting ROP, because it is definitely safer than oral administration, inexpensive and an easily affordable treatment. Establishing the optimal dosage and treatment schedule is to date a crucial issue.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02504944, registered on July 19, 2015, updated July 12, 2016. EudraCT Number 2014-005472-29.

A Case of Syphilitic Uveitis in Which Vitreous Surgery Was Useful for the Diagnosis and Treatment

Purpose

To report a case of atypical syphilitic uveitis complicated with retinal vasculitis, proliferative retinopathy, and vitreous hemorrhage in which vitreous surgery was useful for the diagnosis and treatment.

Case Report

A 38-year-old female was referred to our hospital after noticing visual disturbance in her right eye. Fundoscopy examination of that eye revealed retinal phlebitis accompanied by retinal hemorrhage and soft exudate, and remarkable exudative changes in the retinal vessels from the upper arcade to the macula region. After a blood examination, a serological test showed positive for syphilis; however, systemic findings were scarce. Syphilitic uveitis was suspected, so we administered treatment for syphilis, anticoagulant treatment for retinal vasculitis, steroids for intraocular inflammation, and photocoagulation for the retinal nonperfusion area. However, her visual acuity (VA) decreased to 30 cm/counting fingers due to vitreous hemorrhage resulting from fibrovascular membrane at the optic disc. Since the vitreous hemorrhage was insufficiently absorbed, vitreous surgery was performed to remove the hemorrhage and fibrovascular tissue. Following surgery, the uveitis and retinal vasculitis subsided, and her corrected VA improved to 0.3. Postoperative examination of a fixed quantity of collected vitreous fluid for syphilis showed a Treponema pallidum hemagglutination value of 5,120 times the normal amount, thus confirming the syphilitic uveitis diagnosis.

Conclusions

Our findings show that when observing patients with obstructive retinal vasculitis of unknown causes, syphilitic uveitis should be considered as a differential diagnosis, and that vitreous surgery is useful for the diagnosis and treatment of atypical syphilitic uveitis which has progressed to proliferative retinopathy.

A Case of Proliferative Retinopathy Complicated with Tuberous Sclerosis Treated by Vitreous Surgery

We report a case of proliferative retinopathy complicated with retinal hamartoma in a tuberous sclerosis patient. This study involved a 16-year-old female patient who was diagnosed as having tuberous sclerosis at birth. Ophthalmic examination revealed retinal hamartoma surrounding the optic disc in both eyes. Vitreous surgery involving a vitrectomy and resection of the proliferative membranes was performed for proliferative retinopathy in her right eye. Postoperative fundus findings showed improvement and decreased exudative changes. The proliferative and exudative changes appeared to be due to the retinal hamartoma, and vitreous surgery proved effective in this case.

Serum fibroblast growth factor 21 concentrations in type 2 diabetic retinopathy patients

AIMS/PURPOSE

Fibroblast growth factor 21 (FGF21) is a major metabolic regulator in the body that has been shown to be elevated in a number of metabolic disturbances including type 2 diabetes mellitus (T2DM) and the metabolic syndrome. However, little is known regarding the circulating levels of FGF21 in type 2 diabetic retinopathy (T2DR) and its association with the severity of the condition.

METHODS

In a cross-sectional setting, 142 individuals, consisting of (1) T2DM patients without T2DR, (2) T2DM patients with T2DR, and (3) healthy control subjects were recruited for this study. Various clinical and biochemical parameters were assessed and entered for analysis.

RESULTS

Serum FGF21 levels were significantly elevated in T2DM subjects without retinopathy (103.50 [75.75] pg/mL) compared with healthy controls (99.00 [126.75] pg/mL). Circulating FGF21 levels were comparable across different stages of T2DR (233.00 [109.00] for nonproliferative type 2 diabetic retinopathy [NPT2DR] vs. 215.00 [122.00] for proliferative type 2 diabetic retinopathy [PT2DR] groups, P=361). FGF21, triglycerides, and duration of diabetes mellitus were significantly associated with T2DM in baseline models. However, after adjustment for potential confounders, in the final multivariate model, FGF21 emerged as the only significant factor associated with T2DM (OR=13.772, 95% CI=3.062-61.948, P=001).

CONCLUSIONS

Serum FGF21 concentrations are markedly elevated in patients with T2RN. The association between FGF21 and T2DR appears to be independent of the effects of potential confounding variables. These findings may suggest FGF21 as a novel surrogate diagnostic biomarker in initial stages of T2DR (particularly with FGF21 values above 135.5pg/mL).

Genome-wide association study for sight-threatening diabetic retinopathy reveals association with genetic variation near the GRB2 gene

AIMS/HYPOTHESIS

Diabetic retinopathy is a serious complication of diabetes mellitus and can lead to blindness. A genetic component, in addition to traditional risk factors, has been well described although strong genetic factors have not yet been identified. Here, we aimed to identify novel genetic risk factors for sight-threatening diabetic retinopathy using a genome-wide association study.

METHODS

Retinopathy was assessed in white Australians with type 2 diabetes mellitus. Genome-wide association analysis was conducted for comparison of cases of sight-threatening diabetic retinopathy (n = 336) with diabetic controls with no retinopathy (n = 508). Top ranking single nucleotide polymorphisms were typed in a type 2 diabetes replication cohort, a type 1 diabetes cohort and an Indian type 2 cohort. A mouse model of proliferative retinopathy was used to assess differential expression of the nearby candidate gene GRB2 by immunohistochemistry and quantitative western blot.

RESULTS

The top ranked variant was rs3805931 with p = 2.66 × 10(-7), but no association was found in the replication cohort. Only rs9896052 (p = 6.55 × 10(-5)) was associated with sight-threatening diabetic retinopathy in both the type 2 (p = 0.035) and the type 1 (p = 0.041) replication cohorts, as well as in the Indian cohort (p = 0.016). The study-wide meta-analysis reached genome-wide significance (p = 4.15 × 10(-8)). The GRB2 gene is located downstream of this variant and a mouse model of retinopathy showed increased GRB2 expression in the retina.

CONCLUSIONS/INTERPRETATION

Genetic variation near GRB2 on chromosome 17q25.1 is associated with sight-threatening diabetic retinopathy. Several genes in this region are promising candidates and in particular GRB2 is upregulated during retinal stress and neovascularisation.

Vitreous biomarkers in diabetic retinopathy: a systematic review and meta-analysis

The aim of this study was to perform a systematic meta-analysis of biomarkers investigated with diabetic retinopathy (DR) in the vitreous, and to explore the molecular pathway interactions of these markers found to be consistently associated with DR. Relevant databases [PubMed and ISI web of science] were searched for all published articles investigating molecular biomarkers of the vitreous associated with DR. Based on set exclusion/inclusion criteria available data from studies with human vitreous samples were extracted and used for our meta-analysis. The interactions of significant biomarkers in DR were investigated via STRING and KEGG pathway analysis. Our meta-analysis of DR identifies eleven biomarkers as potential therapeutic candidates alternate to current anti-VEGF therapy. Four of these are deemed viable therapeutic targets for PDR; ET receptors (ET A and ET B), anti-PDGF-BB, blocking TGF-β using cell therapy and PEDF. The identification of supplementary or synergistic therapeutic candidates to anti VEGF in the treatment of DR may aid in the development of future treatment trials.

Oxygen-induced retinopathy in mice with retinal photoreceptor cell degeneration

AIMS

It is reported that retinal neovascularization seems to rarely co-exist with retinitis pigmentosa in patients and in some mouse models; however, it is not widely acknowledged as a universal phenomenon in all strains of all animal species. We aimed to further explore this phenomenon with an oxygen-induced retinopathy model in mice with retinal photoreceptor cell degeneration.

MAIN METHODS

Oxygen-induced retinopathy of colored and albino mice with rapid retinal degeneration were compared to homologous wild-type mice. The retinas were analyzed using high-molecular-weight FITC-dextran stained flat-mount preparation, hematoxylin and eosin (H&E) stained cross-sections, an immunohistochemical test for vascular endothelial growth factor (VEGF) distribution and Western blotting for VEGF expression after exposure to hyperoxia between postnatal days 17 (P17) and 21.

KEY FINDINGS

Leakage and areas of non-perfusion of the retinal blood vessels were alleviated in the retinal degeneration mice. The number of preretinal vascular endothelial cell nuclei in the retinal degeneration mice was smaller than that in the homologous wild-type mice after exposure to hyperoxia (P<0.01). The degree of oxygen-induced retinopathy was positively correlated with the VEGF expression level. However, the VEGF expression level was lower in the retinal degeneration mice.

SIGNIFICANCE

Proliferative retinopathy occurred in mice with rapid retinal degeneration, but retinal photoreceptor cell degeneration could partially restrain the retinal neovascularization in this rapid retinal degeneration mouse model.