Vasoproliferative Retinopathies Research Articles

Formulation development of thermoresponsive quercetin nanoemulgels and in vitro investigation of their inhibitory activity on vascular endothelial growth factor-A inducing neovascularization from the retinal pigment epithelial cells

Quercetin is one of natural flavonoids. It has ability to hinder neovascularization in cancers by reducing activities of the vascular endothelial growth factor-A (VEGF-A). Regarding this particular activity, quercetin thus has a potential for managing the vasoproliferative retinopathies. Unfortunately, its hydrophobicity resulted in poor ocular bioavailability. A suitable intravitreal formulation should be developed to overcome this problem. This study was conducted to optimize formulations of thermoresponsive quercetin nanoemulgels (T-QNE-Gs) for intravitreal injection and to examine their in vitro for their inhibitory activity on VEGF-A inducing neovascularization from the retinal pigment endothelial cells. T-QNE-Gs were prepared by incorporation of gels consisting of various ratios of Pluronic F127 (F127) to Pluronic F68 (F68), with a fixed concentration of hydroxypropyl methylcellulose, into a quercetin nanoemulsion concentrate. The optimum formulation of T-QNE-Gs was 2F127–1F68 containing F127 and F68 at a 2:1 ratio. After sterilization, S–2F127–1F68 was obtained. The S–2F127–1F68 could flow properly at a room temperature (27 ± 1 °C) and became gel at a temperature of the posterior eye segment (35 ± 1 °C). It effectively inhibited migration and tube formation of the human umbilical vein endothelial cells and suppressed the VEGF-A gene expression and VEGF-A protein levels in the arising retinal pigment epithelial cells under a hypoxic condition. Therefore, S–2F127–1F68 had a potential for treatment of the vassoproliferative retinopathies and can be used for further investigation in animal models.

Immunometric and functional measurement of endogenous vasoinhibin in human sera.

Circulating levels of the antiangiogenic protein vasoinhibin, a fragment of prolactin, are of interest in vasoproliferative retinopathies, preeclampsia, and peripartum cardiomyopathy; however, it is difficult to determine the circulating levels of vasoinhibin due to the lack of quantitative assays. This study used human serum samples to assess the concentration and bioactivity of vasoinhibin using a novel enzyme-linked immunosorbent assay (ELISA) for human vasoinhibin, which employs an anti-vasoinhibin monoclonal antibody, a human umbilical vein endothelial cell (HUVEC) proliferation assay, and a chick chorioallantoic membrane (CAM) angiogenesis assay. Serum samples from 17 pregnant women without (one group) and with preeclampsia and pregnancy induced hypertension (another group) demonstrated endogenous vasoinhibin concentrations in the range of 5-340 ng/ml. Immunoactive vasoinhibin levels were significantly higher in preeclampsia serum compared to healthy pregnancy serum (mean 63.09 ± 22.15 SD vs. 19.67 ± 13.34 ng/ml, p = 0.0003), as was the bioactive vasoinhibin level as determined by the HUVEC proliferation assay (56.12 ± 19.83 vs. 13.38 ± 4.88 ng/ml, p < 0.0001). There was a correlation between the concentration of vasoinhibin measured by ELISA and the HUVEC proliferation assay (Pearson r = 0.95, p < 0.0001). Healthy serum demonstrated a proangiogenic effect in the CAM assay (p < 0.05, compared to control), while serum from preeclamptic patients demonstrated an antiangiogenic effect (p < 0.05 vs. control), as did recombinant human vasoinhibin and a synthetic circular retro-inverse vasoinhibin analogue (CRIVi45-51). The antiangiogenic effects in the CAM assay and the inhibition of HUVEC proliferation were abolished by addition of the ELISA anti-vasoinhibin monoclonal antibody, but not by mouse IgG. These results demonstrate the first quantitation of endogenous vasoinhibin in human sera and the elevation of it levels and antiangiogenic activity in sera from women with preeclampsia. The development and implementation of a quantitative assay for vasoinhibin overcomes a long-standing barrier and suggests the thorough clinical verification of vasoinhibin as a relevant biomarker.

Incidence and risk factors of Retinopathy of Prematurity – a prospective observational study

Objective Retinopathy of Prematurity (ROP) is a vasoproliferative retinopathy that affects the developing retinal vessels of premature infants. Identification of risk factors is essential for its early detection and intervention. The study was aimed to assess the incidence of ROP and to determine the risk factors associated with ROP. Methods It was a prospective observational study which included preterm neonates admitted in neonatal intensive care unit of a tertiary care hospital in Chennai,Tamil nadu,India from December 2020 to September 2021. Screening for ROP was performed for all neonates below 34 weeks gestation and between 34 to 36 weeks with risk factors for ROP. Association between risk factors and ROP was determined using chi square test for categorical variables and students t test for continuous variables. A p value less than 0.05 was considered significant. Results Of the 140 neonates screened, 45(32.1%) neonates were diagnosed to have ROP. Among the neonates detected to have ROP there were 24(53.3%) male. 34(75.6%) neonates had a birth weight less than 1.75 kg, 27(60%) neonates had a gestational age less than 34 weeks,22 (48.9%)neonates were born to primi mothers, 25(55.6%) neonates were delivered by normal vaginal delivery. Among the neonatal risk factors studied, sepsis was found to have a significant association with ROP (p=0.02). ). Risk factors like apnoea, respiratory distress syndrome, intraventricular hemorrhage, oxygen therapy and blood transfusion did not have a significant association with ROP. Conclusion The present study revealed an incidence of ROP of 32% and there was significant association with sepsis.

English

BACKGROUND Retinopathy of prematurity (ROP) also known as retrolental fibroplasia is a vasoproliferative retinopathy which affects the retinal blood vessels in developing state. ROP is one of the major causes of preventable blindness in children. It usually occurs in very low birth weight premature infants. Its presentation varies from complete regression in some, to leaving long term sequelae in others. Our aim was to find the prevalence of ROP in Ganjam district, Odisha. METHODS A prospective study was undertaken in M.K.C.G. Medical College and Hospital along with Christian Hospital and City Hospital, Berhampur, from 01/10/2016 to 30/09/2018. Babies fulfilling the inclusion criteria were screened after 3rd week of life or post-conceptional age of 31 - 33 weeks whichever was at a later date, and followed till 45 weeks of gestation according to stage. The babies were screened by indirect ophthalmoscopy and 28 D lens with the help of infant speculum and scleral depressor after instilling topical anaesthetic 2 % proparacaine. The pupil was dilated with 0.4 % tropicamide and 2.5 % phenylephrine. Analysis of qualitative data was done by chi-square test. RESULTS Out of 123 babies examined, 26 were lost to follow up and 19 out of 97 babies (19.58 %) developed ROP (inclusive of all stages). Low birth weight, low gestational age, duration of oxygen exposure &gt; 2 days, exchange transfusion, septicaemia with positive CRP value were found to be significant risk factors in development of ROP. Hyperbilirubinemia, gender and multiple gestation were found to be insignificant in the development of ROP. CONCLUSIONS Timely screening, regular follow-up, early detection and intervention are the best ways to reduce the prevalence of ROP. Neonatal intensive care unit (NICU) should follow strict guidelines for screening of new-borns. Proper counselling and motivation of parents for regular screening of at-risk infants are the need of the hour. KEYWORDS Retinopathy of Prematurity, Low Birth Weight, Low Gestational Age, Oxygen Exposure, Exchange Transfusion

A Prospective Study on Retinopathy of Prematurity in a Teritiary Care Center

Background: Retinopathy of prematurity (ROP) is a vaso-proliferative retinopathy which occurs mostly in premature babies. The pathological change in ROP is peripheral retinal neovascularisation which may regress completely or leave sequelae from mild myopia to bilateral total blindness. International classification of ROP helped in uniform documentation and staging of ROP. In India, the incidence of ROP is between 38 and 51.9 p.c among low-birth-weight infants. Aim &amp; Objectives: To estimate the incidence of ROP among premature and / or low birth weight babies who were born and admitted to neonatal intensive care unit and attending neonatal follow-up clinic.Subjects and Methods:A hospital based, prospective analytical cross-sectional study was conducted in Department of Pediatrics at Shadan Institute of Medical Sciences, Teaching hospital and research center, Hyderabad, Telangana for a period of 6 months from 1st October 2018 to 31st March 2019. Prior to the study initiation, ethical clearance was obtained and written consent was taken from the parents of the respective babies. The study subjects included premature babies (less than or equal to 35 weeks of gestation) or low birth weight babies (less than or equal to 1500 grams). A predesigned, pre-tested, semi-structured proforma was used to collected the data. The data was collected, entered in Microsoft excel-2013 and analyzed using SPSS version-22 (trial). Data was presented in percentages, proportions and figures.Result:The ROP incidence in the study group was reported among 17.1 p.c of the study subjects.Conclusion:Low birth weight and prematurity are important risk factors for ROP.

Vasoproliferative retinopathy secondary to Waldenström's disease

A 66 year-old patient, monitored for diabetic retinopathy refractory to multiple treatment methods despite a good metabolic control, referred to progressive weight loss. For this reason, a systemic study was performed, detecting anaemia, elevation of the erythrocyte sedimentation rate, and hyperproteinaemia due to elevated serum levels of monoclonal IgM. Subsequently, by performing a bone marrow biopsy and genetic study, the diagnosis of Waldenstrom macroglobulinaemia was made. Waldenstrom's macroglobulinaemia is a low frequency lymphoproliferative disease, for which the main manifestation is a hyperviscosity syndrome that can produce ophthalmological signs detectable by funduscopy and imaging tests. A multimodal study is useful in the diagnosis and monitoring of retinal involvement. The incorporation of angiography by optical coherence tomography allows a more precise study of the microvascular disorders that may occur at the posterior pole level.

Nerve growth factor regulates endothelial cell survival and pathological retinal angiogenesis.

The mechanism underlying vasoproliferative retinopathies like retinopathy of prematurity (ROP) is hypoxia‐triggered neovascularisation. Nerve growth factor (NGF), a neurotrophin supporting survival and differentiation of neuronal cells may also regulate endothelial cell functions. Here we studied the role of NGF in pathological retinal angiogenesis in the course of the ROP mouse model. Topical application of NGF enhanced while intraocular injections of anti‐NGF neutralizing antibody reduced pathological retinal vascularization in mice subjected to the ROP model. The pro‐angiogenic effect of NGF in the retina was mediated by inhibition of retinal endothelial cell apoptosis. In vitro, NGF decreased the intrinsic (mitochondria‐dependent) apoptosis in hypoxia‐treated human retinal microvascular endothelial cells and preserved the mitochondrial membrane potential. The anti‐apoptotic effect of NGF was associated with increased BCL2 and reduced BAX, as well as with enhanced ERK and AKT phosphorylation, and was abolished by inhibition of the AKT pathway. Our findings reveal an anti‐apoptotic role of NGF in the hypoxic retinal endothelium, which is involved in promoting pathological retinal vascularization, thereby pointing to NGF as a potential target for proliferative retinopathies.

DNA Repair Response Adaptors: Novel Targets for Vasoproliferative Retinopathy?

DNA Repair Response Adaptors: Novel Targets for Vasoproliferative Retinopathy?

Retinal energy demands control vascular supply of the retina in development and disease: The role of neuronal lipid and glucose metabolism.

Neuronal energy demands are met by a tightly coupled and adaptive vascular network that supplies nutrients and oxygen. The retina is one of the highest energy-consuming organs, exceeding the metabolic rate of the brain; blood vessels grow and regress in reaction to changes in these high demands (Ames et al., 1992b; Anderson and Saltzman, 1964; Yu and Cringle, 2001). Reduced nutrients and reduced oxygen availability instigate compensatory albeit misguided pathological neovascularization in proliferative retinopathies (Chen and Smith, 2007; Sapieha et al., 2010). Conversely, impaired retinal ganglion cell (RGC) and photoreceptor survival are correlated with abrogated vascular development (Pennesi et al., 2008) and as neurons degenerate, the retinal vasculature atrophies to match the reduced metabolic requirements (Wang et al., 2000). In mice, genetic ablation of retinal ganglion cell neurons suppresses the inner retinal vascular development (Sapieha et al., 2008). Ablation of amacrine interneurons also prevents the development of the intermediate vascular plexus (Usui et al., 2015), while photoreceptor degeneration is associated with thinning of the choroid and inner retinal blood vessels (Ayton et al., 2013; Dhoot et al., 2013; Toto et al., 2016). Thinning of the choriocapillaris, in turn, may exacerbate retinal degeneration (Bird, 2010; Whitmore et al., 2015). However, the specific mediators that link neuronal metabolism with retinal angiogenesis in the developing eye and retinal disease remain largely unknown. Conditions such as diabetic retinopathy, vaso-proliferative retinopathy of prematurity and neovascular age-related macular degeneration (AMD) have been characterized as diseases of the vasculature. However, it is becoming more evident that the metabolic needs of the neural retina profoundly influence blood vessel supply in development and in disease. Retinal oxygen sources and the vaso-proliferative response to low oxygen levels have been well characterized. However, understanding the specific fuels used in the retina to generate ATP and supply building blocks for biosynthesis, as well as understanding the vaso-proliferative response to the lack of fuel are also key to neurovascular development. The metabolic and energy needs of the retina have been assumed to be met by glucose, as the retina is part of the CNS, and the brain relies almost exclusively on glucose (Mergenthaler et al., 2013). There are two primary pathways that cells can use to generate ATP from glucose, glycolysis and oxidative phosphorylation. However, Cohen and Noell concluded in 1960 that a substantial portion of the energy produced through oxidation by the retina (around 65%) was not derived from glucose (Cohen and Noell, 1960). We recently showed that the retina (photoreceptors) can also oxidize lipid through fatty acid β-oxidation to produce ATP, accounting for the energy gap noted by Cohen (Joyal et al., 2016). Little is known about lipid versus glucose fuel substrate preference and its importance during retinal development and pathology. Here we review the neuronal energy demands of the retina, describing both glucose and lipid metabolism as forces that shape the vascular supply of the eye in development and in vaso-proliferative eye diseases.

Eye-Opening Potential for Tetraspanin Tspan12 as a Therapeutic Target for Diseases of the Retinal Vasculature

Article, see p 180 Age-related macular degeneration is the leading cause of blindness in industrialized nations, affecting >10 million Americans. The most severe form of macular degeneration, the “wet” form, is caused by growth of abnormal vessels that leak excessive fluid under the retina, damaging the macula and leading to loss of sharp, central, color vision. Vascular endothelial growth factor (VEGF) is a major factor that drives vasoproliferative diseases such as macular degeneration, and antibodies to VEGF are a mainstay of treatment. In this issue of Circulation ,1 Bucher and colleagues identify tetraspanin Tspan12 as a therapeutic target for retinal vascular proliferation, and they invent a Tspan12-targeting therapy. The retinal vasculature is uniquely adapted to supply oxygen and nutrients to photoreceptor cells without blocking incoming light. However, these specialized features also make the retinal vasculature susceptible to vasoproliferative retinopathy, which is the aberrant growth of new blood vessels and breakdown of their barrier function.2 Vasoproliferative retinopathies are driven by VEGF, a key regulator of physiological and pathological angiogenesis. VEGF production is driven primarily by the hypoxia-inducible factor family of transcription factors. VEGF stimulates angiogenesis by interacting with its receptors VEGFR1 and VEGFR2, which in turn activate intracellular signaling cascades such as the Ras-mitogen-activated protein kinase pathway, triggering endothelial migration and proliferation. VEGF-induced VEGFR2 signaling also increases vascular permeability by separating VE-cadherin complexes and intercellular adhesion junctions. The most effective treatment for vasoproliferative retinopathies is anti-VEGF therapy delivered by periodic intravitreal injections. However, the lack of response in some patients and relapses of neovascularization and edema between treatments indicate the clinical need for novel treatments.2 In the current issue of Circulation , Bucher and colleagues1 discovered that tetraspanin Tspan12 is a new therapeutic target for vasoproliferative retinopathies. The tetraspanins are a superfamily of 33 integral membrane with …

Pediatric Retinal Detachment

The number of retinal detachments in children is rarely compared to the number of retinal detachments in adults; only 3 - 7% occur in children. The main predisposing factors are trauma, myopia, hereditary vitreoretinopathies, retinopathy of prematurity, malformations and Coats' disease. The most frequent paediatric retinal detachments are trauma-associated and vitreoretinopathies are the most common cause of inherited retinal detachment. Disease-specific surgical treatments are discussed. Episcleral buckling surgery should be the preferred method in any case of clear lens, especially for treatment of oradialysis and well-defined localization of peripherally retinal tears. In those suffering from vitreoretinopathy, primary vitrectomy is necessary. The intravitreal use of VEGF-inhibitors to treat vasoproliferative retinopathy in children is a new and effective tool, but we need further results about safety and side-effects in young patients. The functional and anatomical outcomes of retinal detachment in children are less successful than in adults. Further surgical innovations and etiology-specific treatment strategies are required to improve the outcome in this group.

Antibody-Mediated Inhibition of Tspan12 Ameliorates Vasoproliferative Retinopathy Through Suppression of β-Catenin Signaling.

Anti-angiogenic biologicals represent an important concept for the treatment of vasoproliferative diseases. However, the need for continued treatment, the presence of nonresponders, and the risk of long-term side effects limit the success of existing therapeutic agents. Although Tspan12 has been shown to regulate retinal vascular development, nothing is known about its involvement in neovascular disease and its potential as a novel therapeutic target for the treatment of vasoproliferative diseases. Rodent models of retinal neovascular disease, including the mouse model of oxygen-induced retinopathy and the very low density lipoprotein receptor knockout mouse model were analyzed for Tspan/β-catenin regulation. Screening of a phage display of a human combinatorial antibody (Ab) library was used for the development of a high-affinity Ab against Tspan12. Therapeutic effects of the newly developed Ab on vascular endothelial cells were tested in vitro and in vivo in the oxygen-induced retinopathy and very low density lipoprotein receptor knockout mouse model. The newly developed anti-Tspan12 Ab exhibited potent inhibitory effects on endothelial cell migration and tube formation. Mechanistic studies confirmed that the Ab inhibited the interaction between Tspan12 and Frizzled-4 and effectively modulates β-catenin levels and target genes in vascular endothelial cells. Tspan12/β-catenin signaling was activated in response to acute and chronic stress in the oxygen-induced retinopathy and very low density lipoprotein receptor mouse model of proliferative retinopathy. Intravitreal application of the Ab showed significant therapeutic effects in both models without inducing negative side effects on retina function. Moreover, combined intravitreal injection of the Ab with a known vascular endothelial growth factor inhibitor, Aflibercept, resulted in significant enhancement of the therapeutic efficacy of each monotherapy. Combination therapy with the Tspan12 blocking antibody can be used to reduce anti-vascular endothelial growth factor doses, thus decreasing the risk of long-term off-target effects. Tspan12/β-catenin signaling is critical for the progression of vasoproliferative disease. The newly developed anti-Tspan12 antibody has therapeutic effects in vasoproliferative retinopathy and can enhance the potency of existing anti- vascular endothelial growth factor agents.

Refractive errors in premature infants with retinopathy of prematurity after anti-vascular endothelial growth factor (anti-VEGF) therapy

Background/Aim. Retinopathy of prematurity (ROP) is a vasoproliferative retinopathy which affects the blood vessels of the retina during its development. The aim of this study was to evaluate the incidence and the degree of refractive errors in premature infants with severe ROP treated with antivascular endothelial growth factor (anti-VEGF) (bevacizumab). Methods. This prospective study included 21 patients (42 eyes) nine months old who received intravitreal injection of anti-VEGF therapy. The control group consisted of 45 patients (90 eyes) who were subjected to laser treatment. In cycloplegia each patient underwent retinoscopy, keratorefractometry, and A-scan ultrasonography. Results. Myopia was present in 47.62% of the eyes in the study group and in 33.33% of the eyes in the control group, but there were no statistically significant differences between these groups. Seven (16.67%) eyes in the study group and 17 (18.89%) eyes in the control group were discovered to have high myopia (SE? spherical equivalents &lt; -3.0 D ? dioptre). Clinically significant hypermetropia was higher in the study group (47.62%) than in the control group (34.44%), but with no statistically significant difference. In addition, high hypermetropia was significantly greater in the control group (15.56%) than in the study group (11.90%) (p &lt; 0.001). Astigmatism was more common in the control group than in the study group (81.11% vs 71.43%, respectively), especially high astigmatism (56% vs 43%, respectively). Also the more common form of astigmatism was with the rule (WTR) both in the study and the control group (42.86% vs 55.56%, respectively). Anisometropia was significantly greater in the control group (24.44%) than in the study group (9.52%) (p &lt; 0.05). The children from the study group had significantly greater lens thickness, and a shorter anterior chamber depth than children from the control group (p &lt; 0.01). There was no significant difference in the axial length of the eye between the groups. Conclusion. At the 9-month follow-up myopia was present in the patients with severe ROP treated with anti-VEGF, but high myopia was present to a lesser degree than in the laser treated patients. This difference is possibly related to anterior segment development. Research into the longer-term refractive outcomes is necessary with observation of the biometric components, visual acuity, and the visual field in order to monitor the real effects of this therapy.

Analysis of CCN Protein Expression and Activities in Vasoproliferative Retinopathies.

The retina is a complex neurovascular structure that conveys light/visual image through the optic nerve to the visual cortex of the brain. Neuronal and vascular activities in the retina are physically and functionally intertwined, and vascular alterations are consequential to the proper function of the entire visual system. In particular, alteration of the structure and barrier function of the retinal vasculature is commonly associated with the development of vasoproliferative ischemic retinopathy, a set of clinically well-defined chronic ocular microvascular complications causing blindness in all age groups. Experimentally, the retinal tissue provides researchers with a convenient, easily accessible, and directly observable model suitable to investigate whether and how newly identified genes regulate vascular development and regeneration. The six mammalian CCN gene-encoded proteins are part of an extracellular network of bioactive molecules that regulate various aspects of organ system development and diseases. Whether and how these molecules regulate the fundamental aspects of blood vessel development and pathology and subsequently the neurovascular link in the retina are open-ended questions. Sophisticated methods have been developed to gain insight into the pathogenesis of retinal vasculopathy. This chapter describes several useful methodologies and animal models to investigate the regulation and potential relevance of the CCN proteins in vasoproliferative diseases of the retina.

CNTF Attenuates Vasoproliferative Changes Through Upregulation of SOCS3 in a Mouse-Model of Oxygen-Induced Retinopathy.

PurposeRetinal vascular disease represents a major cause for vision loss in the Western world. Recent research has shown that neuronal and vascular damage are closely related in retinal disease. Ciliary neurotrophic factor (CNTF) is a well-studied neurotrophic factor that is currently being tested in clinical trials for the treatment of retinal degenerative diseases and macular telangiectasia. However, little is known about its effect on retinal vasculature. In this study, we investigate the effects of CNTF in retinal neovascular disease using the mouse model of oxygen-induced retinopathy (OIR).MethodsNewborn pups were exposed to 75% oxygen from postnatal day (P)7 to P12 and subsequently returned to room air. Ciliary neurotrophic factor was injected intravitreally at OIR P12 and the vaso-obliterated and neovascular areas were quantified at OIR P17. Immunohistochemistry, RNA, and protein analysis were used to identify CNTF-responsive cells. In vitro experiments were performed to analyze the effect of CNTF on endothelial and astroglial cells.ResultsIn the OIR model, CNTF facilitated capillary regrowth and attenuated preretinal neovascularization in a dose-dependent manner. The protective effect of CNTF was mediated via activation of the JAK/STAT3/SOCS3 signaling pathway. Immunohistochemical studies identified endothelial cells among others as CNTF-responsive cells in the retina. In vitro studies confirmed the anti-angiogenic effect of CNTF on endothelial cell sprouting.ConclusionsThis study provides evidence for a therapeutic potential of CNTF beyond degenerative retinal disease. Vasoproliferative retinopathies may benefit from a CNTF-dependent and SOCS3-mediated angiomodulatory effect.

AMA0428, A Potent Rock Inhibitor, Attenuates Early and Late Experimental Diabetic Retinopathy

ABSTRACTPurpose: Diabetic retinopathy (DR) is characterized by an early stage of inflammation and vessel leakage, and an advanced vasoproliferative stage. Also, neurodegeneration might play an important role in disease pathogenesis. The aim of this study was to investigate the effect of the Rho kinase (ROCK) inhibitor, AMA0428, on these processes.Methods: The response to ROCK inhibition by AMA0428 (1 µg) was studied in vivo using the murine model for streptozotocin (STZ)-induced diabetes, focusing on early non-proliferative DR features and the oxygen-induced retinopathy (OIR) model to investigate proliferative DR. Intravitreal (IVT) administration of AMA0428 was compared with murine anti-VEGF-R2 antibody (DC101, 6.2 µg) and placebo (H2O/PEG; 1C8). Outcome was assessed by analyzing leukostasis using fluorescein isothiocyanate coupled concanavalin A (FITC-ConA) and vessel leakage (bovine serum albumin conjugated with fluorescein isothiocyanate; FITC-BSA)/neovascularization and neurodegeneration by immunohistological approaches (hematoxylin and eosin (H&E), terminal deoxynucleotidyl transferase–mediated biotinylated UTP nick end labeling (TUNEL), Brn3a). ELISA and Western blotting were employed to unravel the consequences of ROCK inhibition (1 µM AMA0428) on myosin phosphatase target protein (MYPT)-1 phosphorylation, endothelial nitric oxide synthase (eNOS) phosphorylation, and vascular endothelial growth factor (VEGF) levels in retinas of diabetic mice, on NF-κβ activity and ICAM-1 expression in endothelial cells (ECs).Results: In vivo, AMA0428 significantly reduced vessel leakage and neovascularization, respectively, in the STZ and OIR model, comparable to DC101 therapy. Additionally, the ROCK inhibitor decreased neurodegeneration in both models and inhibited leukostasis by 30% (p < 0.05) in the STZ model (p < 0.05), while DC101 had no positive effect on the outcome of these latter processes. ROCK activity was upregulated in the diabetic retina and AMA0428 administration resulted in decreased phospho-MYPT-1, enhanced phospho-eNOS, and reduced VEGF levels. In vitro, AMA0428 interfered with NF-κβ activity, thereby inhibiting ICAM-1 expression in ECs.Conclusions: Targeting ROCK with AMA0428 effectively attenuated outcome in an early DR model (STZ) and a late vasoproliferative retinopathy model (OIR). These findings make AMA0428 a promising candidate with an additional anti-inflammatory and neuroprotective benefit for DR patients, as compared with anti-VEGF treatment.

La preeclampsia y su relacion con la retinopatia de la prematuridad en recien nacidos de muy bajo peso. Instituto Nacional Materno Perinatal 2013-2014

La Retinopatía de la Prematuridad (ROP) es una retinopatía vaso-proliferativa que afecta a los recién nacidos inmaduroscuya etiología es aún desconocida. Algunos estudios han sugerido la asociación entre la preeclampsia y ésta patología.Se hizo un estudio para demostrar si la preeclampsia se relaciona con la incidencia de retinopatía en los recién nacidosprematuros en el Instituto Nacional Materno Perinatal. El estudio retrospectivo, comparativo longitudinal de casos –control,comprende a prematuros de muy bajo peso al nacer (&lt; 1500 grs.) y menor de 32 semanas, nacidos entre el 1º de Enerodel 2013 al 31 de Diciembre del 2014 que cumplieron con los criterios de inclusión. Se consideró 201 pacientes y éstosfueron divididos en dos grupos, uno con el antecedente de haber nacido de madre preeclampticas (estudio) y otro sin esteantecedente (control) .Ambos grupos, fueron homogéneos en edad, sexo peso. Se comparó la incidencia de ROP en ambosgrupos, presentando algún grado de ROP 25 de 97 pacientes con el antecedente de haber nacido de madre preeclampticas(25,8 %) y 34 de 104 pacientes sin el antecedente de haber nacido de madre preeclampticas (32,7 %). Se determinó queno hubo relación entre la incidencia de ROP y madre pre eclámpticas (OR) 0,71 IC 95 % (0,4-1,3). Se concluye que la preeclampsia no es un factor de riesgo para desarrollar ROP en nacidos prematuros de muy bajo peso pero si existe relacióncon la severidad de ROP.

BIBF1120 (Vargatef) Inhibits Preretinal Neovascularization and Enhances Normal Vascularization in a Model of Vasoproliferative Retinopathy

This study evaluated the effects of BIBF1120, a novel triple angiokinase inhibitor against pathological retinal neovascularization. BIBF1120 effect on development of the normal retinal vasculature was evaluated in Sprague-Dawley rat pups. Two models of ischemic oxygen-induced retinopathy (OIR) and the aortic ring assay were used to assess the antiangiogenic effects of BIBF1120. In the vaso-obliteration model (VO), rat pups were exposed to 80% O2 from postnatal day (P) 5 to P10. In the preretinal neovascularization (NV) model, rat pups were exposed to cycling O2 (50% and 10%) from P1 to P14, followed by room air until P18. Animals were intravitreally or orally treated with BIBF1120. Retinal vasculature, VO, and NV were evaluated in retinal flat mounts. Retinal expression of VEGF, Delta-like ligand 4 (Dll4), Netrin-1, Ephrin-B2, and EphB4 was analyzed by quantitative PCR and Western blot analysis. BIBF1120 interfered with normal retinal vascular development and microvessel branching in the aortic assay. However, in VO model BIBF1120 did not accrue VO. On the contrary, in the NV model BIBF1120 accelerated normal retinal vascularization and robustly diminished preretinal neovascularization compared to vehicle (by ~80%). The expression levels of VEGF negative regulator Dll4 and repulsive cues EphrinB2 and EphB4 mRNA in the retina of vehicle-treated OIR animals were markedly increased compared to normoxia, but were normalized by BIBF1120. Data reveal efficacy of BIBF1120 on preretinal neovascularization and, of greater interest, on acceleration of normal vascularization, consistent with interference of major repulsive cues expressed in the retina during OIR. Accordingly, BIBF1120 appears to exhibit preferable properties compared to anti-VEGF therapies for the treatment of ischemic retinopathies.

Suppression of transient receptor potential canonical channel 4 inhibits vascular endothelial growth factor-induced retinal neovascularization

Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis and thus contributes to many vasoproliferative retinopathies including retinopathy of prematurity. Based on the importance of canonical transient receptor potential (TRPC) channels in VEGF signaling, we firstly evaluated the expression of TRPC channels in mouse retina by reverse transcriptase-polymerase chain reaction. All seven TRPC channels were expressed in mouse retina. TRPC4 channels were chosen for further analysis based on their upregulation on hypoxic retina according to the GEO database under the identifier GSE19886. Interestingly, TRPC4 suppression by intravitreal injection of siRNA against mTRPC4 significantly inhibited retinal neovascularization. To further investigate the effect of TRPC4 suppression on neovascularization, human retina microvascular endothelial cells (HRMECs) that are responsible for initiating neovascularization in response to increased VEGF in OIR retina were transfected with siRNA against TRPC4. As we have expected, suppression of TRPC4 effectively inhibited VEGF-induced migration and tube formation as well. Further evaluation on VEGF signaling pathway by western blot analysis of signaling molecules discovered that VEGF-induced activation of ERK, p38 MAPK and AKT signaling pathways were inhibited by suppression of TRPC4. These findings suggest that suppression of TRPC4 could be an alternative therapeutic option for VEGF-induced retinal neovascularization.

Outcome of transpupillary diode laser photocoagulation for retinal diseases

Background: Diode lasers have been used in ophthalmic practice for several years. They are useful in the management of vasoproliferative retinopathies and have been shown to be comparable in efficacy to the argon laser. Aim: To report on the outcome of transpupillary diode laser treatment for retinal diseases. Patients and Methods: A retrospective study carried out using the case files of patients that had retinal diode laser photocoagulation between June 2011 and May 2012 at the Jos University Teaching Hospital, Jos, Nigeria. Information retrieved included patients' age, sex, diagnosis, indication for retinal laser photocoagulation, prelaser and postlaser visual acuity (VA), best corrected VA, and operative complications. Results: A total of 31 eyes of 21 patients had transpupillary retinal laser photocoagulation during the study period. The commonest indication for retinal laser photocoagulation was proliferative diabetic retinopathy (PDR), and this was seen in 16 eyes (52%). Six eyes (19%) had both PDR and clinically significant macular edema (CSMO), while 3 eyes had CSMO only. Other indications were retinal vein occlusion (RVO) with secondary neovascularization (four eyes), proliferative sickle cell retinopathy (one eye), and traumatic retinal tear (one eye). Following laser therapy in those with diabetic retinopathy, VA improved by at least a line in 6 eyes, remained the same in 13 eyes, and deteriorated in 2 eyes. Neovascular regression was observed in 13 eyes and resolution of macular edema in 3 eyes. In the eyes with RVO, neovascular regression was observed in two eyes. Conclusion: Transpupillary diode laser photocoagulation was beneficial in the treatment of retinal diseases. Fibrovascular proliferation with significant fibrous tissue component was, however, associated with poor response to laser treatment in proliferative retinopathies.