Largazole Inhibits Ocular Angiogenesis by Modulating the Expression of VEGFR2 and p21.

Ocular angiogenic diseases, characterized by abnormal blood vessel formation in the eye, are the leading cause of blindness. Although Anti-VEGF therapy is the first-line treatment in the market, a substantial number of patients are refractory to it or may develop resistance over time. As uncontrolled proliferation of vascular endothelial cells is one of the characteristic features of pathological neovascularization, we aimed to investigate the role of the class I histone deacetylase (HDAC) inhibitor Largazole, a cyclodepsipeptide from a marine cyanobacterium, in ocular angiogenesis. Our study showed that Largazole strongly inhibits retinal vascular endothelial cell viability, proliferation, and the ability to form tube-like structures. Largazole strongly inhibits the vessel outgrowth from choroidal explants in choroid sprouting assay while it does not affect the quiescent choroidal vasculature. Largazole also inhibits vessel outgrowth from metatarsal bones in metatarsal sprouting assay without affecting pericytes coverage. We further demonstrated a cooperative effect between Largazole and an approved anti-VEGF drug, Alflibercept. Mechanistically, Largazole strongly inhibits the expression of VEGFR2 and leads to an increased expression of cell cycle inhibitor, p21. Taken together, our study provides compelling evidence on the anti-angiogenic role of Largazole that exerts its function through mediating different signaling pathways.

Laser Acupuncture in Open-Angle Glaucoma Treatment: A Retrospective Study of Eye Blood Flow.

Patients with glaucoma can show blood flow anomalies at the eye vessel level. A causal relationship is reasonably expected, but so far, it has not been demonstrated. Traditional Chinese medicine indicates that acupuncture can promote specific blood perfusion in specific body districts. Ninety-eight patients with open-angle glaucoma were treated with an ultralow light-level laser, according to a specific acupuncture protocol, and their blood flow was measured before and after a six-week treatment cycle. Doppler measurements showed significant modifications in both pulsatility and resistivity indexes. The most relevant outcome of this study is that the applied treatment demonstrated its effectiveness not only in vasodilation but also in perfusion control that seems to restore appropriate functionality. The protocol therefore should be investigated in future controlled studies and perhaps in other blood perfusion-related pathologies.

Effects of Selenium and Melatonin on Ocular Ischemic Syndrome.

PURPOSE: To determine the effects of selenium, melatonin, and selenium + melatonin administered for one month on anterior chamber (AC) malondialdehyde (MDA) and AC glutathione (GSH) levels in patients with ocular ischemic syndrome. MATERIALS AND METHODS: Thirty-five patients were included in the study. Study groups were formed as follows: (1) control group, (2) ischemia group, (3) selenium + ischemia group, (4) melatonin + ischemia group, and (5) selenium + melatonin + ischemia group. AC samples were obtained. MDA and GSH levels in AC samples were evaluated. RESULTS: MDA levels were significantly increased in ischemia groups. Selenium and melatonin supplementation resulted in reduction of MDA levels and significant increase in GSH values. DISCUSSION: Increased lipid peroxidation associated with ischemia of the anterior segment has been prevented by selenium and melatonin supplementation. This trial is registered with ClinicalTrials.gov NCT04005222.

Gross anterior segment ischaemia following vitreoretinal surgery for sickle-cell retinopathy.

We report the case of a 32-year-old Afrocaribbean man with known stage 3 proliferative sickle-cell retinopathy who presented with a mixed picture of tractional and rhegmatogenous macula off detachment. He underwent left primary 25 g vitrectomy with silicone oil, delamination and endolaser photocoagulation under a general anaesthetic. He, however, presented 48 hours postoperatively with gross anterior segment ischaemia. His pain and ocular signs settled over the course of a few days following administration of supplemental oxygen, oral steroids, analgesia and intravenous hydration. Examination showed resolution of his proptosis and orbital signs as well as anterior segment inflammation. He remains under follow-up.

[Analysis of choline alfoscerate effectiveness in chronic ocular ischemic syndrome].

AIM: To investigate the effectiveness of choline alphoscerate in patients with chronic ocular ischemic syndrome (OIS) and coexisting cerebrovascular disease. MATERIAL AND METHODS: We performed a comprehensive examination of 51 patients aged 46--72 years (57.8±6.82 years on average) and diagnosed with OIS. Patients were divided into two groups. In group 1 (main group, 26 patients) the standard therapy was supplemented with choline alphoscerate. Group 2 (controls, 25 patients) received the standard therapy only. RESULTS: Clinical and functional examinations revealed a more rapid and stable improvement of visual acuity in the choline alphoscerate group. CONCLUSION: Development and application of an adequate combination therapy for patients with ocular ischemic syndrome has yielded an increase in visual acuity, visual fields, and the mean light sensitivity of the retina as well as an improvement of ocular hemodynamics.

Plant-derived flavonoids in ocular angiopathy.

Encouraging reports of flavonoid activity, mainly coming from in vitro or ex vivo experimental evidence, should be replicated in randomized controlled trials, to examine their ability to prevent angiopathy.

Posterior segment changes of the eye during hyperbaric oxygen therapy.

PURPOSE: To examine central retinal thickness, retinal and vitreo-retinal structures, and ocular blood flow during a standard protocol of hyperbaric oxygen (HBO2) therapy. METHODS: Retinal thickness and color scans of the vitreo-retinal structures were obtained before and after 19 days of HBO2 therapy in 15 patients by optical coherence tomography (OCT). Pulsatile ocular blood flow was measured by ocular blood flow tonometry. Ocular refraction and axial length of the eye were monitored for control. RESULTS: Significant reduction was found in mean retinal thickness, -1.7 ± 1.6 µm (range -3.9 to 1.1 µm) (p < 0.001) in nine subfields within the 6-mm-diameter circle around the central macula. An insignificant decrease in pulsatile ocular blood flow of -19.0 ± 148.8 µl/minute was measured. No morphological changes were seen in retinal and vitreo-retinal structures. A mean myopic shift of -0.62 ± 0.39 D (p < 0.001) developed while axial length of the eye remained unchanged. CONCLUSIONS: A small decrease in central retinal thickness was seen during the study period, but the changes were not correlated to the myopic shift. No significant changes in vitreo-retinal structures or ocular pulsatile blood flow occurred.

Highly potent VEGF-A-antagonistic DARPins as anti-angiogenic agents for topical and intravitreal applications.

The next-generation ophthalmic anti-VEGF therapeutics must aim at being superior to the currently available agents with regard to potency and improved drug delivery, while still being stable and safe to use at elevated concentrations. We show here the generation of a set of highly potent VEGF-A antagonistic DARPins (designed ankyrin repeat proteins) delivering these properties. DARPins with single-digit picomolar affinity to human VEGF-A were generated using ribosome display selections. Specific and potent human VEGF-A binding was confirmed by ELISA and endothelial cell sprouting assays. Cross-reactivity with VEGF-A of several species was confirmed by ELISA. Intravitreally injected DARPin penetrated into the retina and reduced fluorescein extravasation in a rabbit model of vascular leakage. In addition, topical DARPin application was found to diminish corneal neovascularization in a rabbit suture model, and to suppress laser-induced neovascularization in a rat model. Even at elevated doses, DARPins were safe to use. The fact that several DARPins are highly active in various assays illustrates the favorable class behavior of the selected binders. Anti-VEGF-A DARPins thus represent a novel class of highly potent and specific drug candidates for the treatment of neovascular eye diseases in both the posterior and the anterior eye chamber.

[Effects of peroxynitrite derived from nitric oxide on cultured bovine ocular explants]. / Effets du peroxynitrite dérivé du monoxyde d'azote sur des explants oculaires bovins en culture.

INTRODUCTION: Several studies have reported a significant production of nitric oxide (NO) with peroxynitrite formation in the setting of intraocular inflammation. In a previous study, we showed the cytotoxic effect of nitrites and nitrates, stable metabolites of NO, on the various tissues forming the layers of the eye, with variable degrees of tissue sensitivity. This study aims to investigate the effect of peroxynitrite on whole ocular bovine explants in culture. METHODS: Healthy ocular bovine eyes, obtained immediately upon enucleation, were dissected and samples were taken from the anterior and posterior segments, and then cultured in DMEM supplemented with 10% fetal bovine serum, 2mM L-glutamine and antibiotics. Cultures were treated with 3-morpholino-sydonimin N-ethyl-carbamide (SIN-1) (molecule which produces NO and superoxide anion O(2)(.-)) at varying concentrations (100 to 500 µM) over 24 hours. After incubation, the explants were fixed in 10% buffered formalin, and histological study was performed. RESULTS: Most of the structures showed changes on tissue and cellular levels after incubation with the peroxynitrite donor and various responses depending on the concentration used. These observations reflect variable concentration-dependent tissue sensitivity. The epithelia (cornea, iris and ciliary process) showed high sensitivity in comparison with sclera, which developed greater resistance. CONCLUSION: In all, our results indicate a deleterious effect of peroxynitrite on bovine ocular structures in vitro. This effect is proportional to the concentration used. These results corroborate those reported by other teams and suggest the role of peroxynitrite derived from NO in the ocular lesions observed in the setting of uveitis.

Carbon monoxide-mediated humoral pathway for the transmission of light signal to the hypothalamus.

The gaseous messenger carbon monoxide (CO) is released from the eye into ophthalmic venous blood depending on the intensity of sunlight. Numerous neurohormones and other regulatory factors permeate from venous blood into arterial blood in the perihypophyseal vascular complex (PVC) and are transferred to the brain by the humoral pathway. This study was designed to determine whether elevated CO in ophthalmic venous blood (OphVB) affects the expression of clock genes and their transcriptional factors in the hypothalamus. Mature males of a wild boar and pig crossbreed (n=24) were used for the study. Autologous plasma with increased concentrations of CO was infused into the ophthalmic sinus (OphS) of the experimental group (n=12). The expression of clock genes (Per1, Per2, Cry1, Cry2, Rev-erb α and Rev-erb ß) and the genes of their regulators (Bmal1, Npas2, Clock, Ror ß) was estimated in two hypothalamic structures involved in the reception and transmission of light signal (the preoptic area (PA) and dorsal hypothalamus (DH)). We demonstrated that the expression of clock genes and the genes of their regulatory factors in the experimental group was altered compared with control, both in the PA and DH. The response to an increased concentration of CO differed between individual genes and the hypothalamic regions. The expression of Per1 which, according to many authors, is regulated by light, was increased in animals treated with CO both in the PA and DH, and regardless of the time of day and season. In conclusion, the current results seem to confirm the hypothesis on the function of CO in humoral transfer from the eye to structures related to the reception and transmission of light signal and the effect of CO on clock gene expression.

Retinal and renal vascular permeability changes caused by stem cell stimulation in alloxan-induced diabetic rats, measured by extravasation of fluorescein.

AIM: To determine whether treatment with the stem cell stimulator Olimpiq® Stem×Cell prevents increase of retinal and renal vascular permeability in alloxan-induced diabetic rats. MATERIALS AND METHODS: Two groups of Wistar rats were made diabetic by single intraperitoneal injection of Alloxan. The third, the control group, received vehicle alone. One diabetic group received Olimpiq® Stem×Cell treatment for 4 weeks. The permeability of the blood-retinal barrier (BRB) and renal vessels were measured by the extravasation of fluorescein-labeled bovine serum albumin. RESULTS: Six weeks subsequently to Alloxan injection, significantly elevated the tissue fluorescence, the renal vascular leakage and BRB breakdown was demonstrated in the diabetic group, compared to the nondiabetic group. Olimpiq® Stem×Cell treatment significantly reduced the BRB breakdown, tissue fluorescence, and vascular leakage. CONCLUSION: Olimpiq® Stem×Cell would be a useful choice of treatment for complications associated with increased vascular permeability of diabetes, such as retinopathy or nephropathy.

Effects of the time of antihypertensive drugs administration on the stage of primary open-angle glaucoma in patients with arterial hypertension.

Many patients with glaucoma suffer from arterial hypertension (AH). It has been proved that both AH and low blood pressure (BP) at night are important vascular risk factors for primary open-angle glaucoma (POAG). The aims of this study were to assess the severity of pathological changes within the optic nerve and characteristics of blood flow in selected arteries of the eyeball and orbit in patients with POAG and controlled hypertension, in relation to the time of hypotensive drugs administration. Eighty-eight patients with POAG and treated, controlled hypertension were examined. The patients were divided into two subgroups, consisting of group A (n = 43), in whom hypotensive drugs were dosed only in the morning and group B (n = 45), in whom hypotensive drugs were also taken in the evening. In patients who were taking hypotensive drugs also in the evening (group B), there was a statistically significant lower mean perfusion pressure at night, a greater visual field loss and reduced amplitude of evoked potentials. Our analysis showed significantly worse changes in the parameters relating to the optic nerve in patients taking hypertensive medicines in the evening and also significantly lower perfusion pressures at night.

Ginkgo biloba: an adjuvant therapy for progressive normal and high tension glaucoma.

Gingko biloba has been used for hundreds of years to treat various disorders such as asthma, vertigo, fatigue and, tinnitus or circulatory problems. Two of the main extracts are EGb761 and LI 1370. Most pharmacological, toxicological and clinical studies have focused on the neuroprotective value of these two main extracts. Neuroprotection is a rapidly expanding area of research. This area is of particular interest due to the fact that it represents a new avenue of therapy for a frustrating disease that may progress despite optimal treatment. One such disease is glaucoma.Glaucoma leads to the loss of retinal ganglion cells and their axons but also to tissue remodelling which involves both the optic nerve head and the retina. In the retina the astrocytes get activated. In addition, the optic nerve gets thinner and the cells of the lateral geniculate ganglion disappear partially. On average, ocular blood flow (OBF) is reduced in glaucoma patients in various tissues of the eye. Increased intraocular pressure (IOP) is a major risk factor for glaucomatous damage. Nevertheless, there is little doubt that other risk factors besides IOP are involved. One such risk factor is a primary vascular dysregulation (PVD) occurring in patients with a disturbed autoregulation, another risk factor is oxidative stress.

Complications of local anesthesia used in oral and maxillofacial surgery.

Local anesthetics are used routinely in oral and maxillofacial surgery. Local anesthetics are safe and effective drugs but do have risks that practitioners need to be aware of. This article reviews the complications of local anesthesia. A brief history is provided and the regional and systemic complications that can arise from using local anesthesia are discussed. These complications include paresthesia, ocular complications, allergies, toxicity, and methemoglobinemia. Understanding the risks involved with local anesthesia decreases the chances of adverse events occurring and ultimately leads to improved patient care.

Nanoceria inhibit the development and promote the regression of pathologic retinal neovascularization in the Vldlr knockout mouse.

Many neurodegenerative diseases are known to occur and progress because of oxidative stress, the presence of reactive oxygen species (ROS) in excess of the cellular defensive capabilities. Age related macular degeneration (AMD), diabetic retinopathy (DR) and inherited retinal degeneration share oxidative stress as a common node upstream of the blinding effects of these diseases. Knockout of the Vldlr gene results in a mouse that develops intraretinal and subretinal neovascular lesions within the first month of age and is an excellent model for a form of AMD called retinal angiomatous proliferation (RAP). Cerium oxide nanoparticles (nanoceria) catalytically scavenge ROS by mimicking the activities of superoxide dismutase and catalase. A single intravitreal injection of nanoceria into the Vldlr-/- eye was shown to inhibit: the rise in ROS in the Vldlr-/- retina, increases in vascular endothelial growth factor (VEGF) in the photoreceptor layer, and the formation of intraretinal and subretinal neovascular lesions. Of more therapeutic interest, injection of nanoceria into older mice (postnatal day 28) resulted in the regression of existing vascular lesions indicating that the pathologic neovessels require the continual production of excessive ROS. Our data demonstrate the unique ability of nanoceria to prevent downstream effects of oxidative stress in vivo and support their therapeutic potential for treatment of neurodegenerative diseases such as AMD and DR.

Carbon monoxide and the eye: Implications for glaucoma therapy.

In the late 1990s, the scientific community witnessed a very peculiar phenomenon: the transformation of nitric oxide (NO) from a noxious gas into a key chemical messenger. The importance of NO in biology and medicine was highlighted in 1998 when the Nobel Prize was awarded in Physiology and Medicine to Robert Furchgott, Louis Ignarro and Ferid Murad for their pioneering work on the role of NO in the nervous, cardiovascular and immune systems. In this same time period, carbon monoxide (CO), another gas usually associated with environmental pollution, air poisoning and suicidal behavior, was also undergoing a similar change in image, although not as closely followed. It had been known for several decades that the human body generated CO upon the decomposition of hemoglobin, which was determined by the discovery that heme oxygenase (HO) is the enzymatic source of CO. However, CO's role as an endogenous neurotransmitter was established only in the early 1990s. Since then, many biological activities of CO have been demonstrated in studies using different tools, such as the pharmacological induction of HO by hemin, the direct administration of CO or the use of pro-drugs that generate CO. This review focuses on CO as a fine modulator of intraocular pressure and on its potential implications in glaucoma.

[The use of biologically controlled ultrasound therapy for the combined treatment of primary open-angle glaucoma].

The present study included 160 patients (206 eyes) presenting with the initial and advanced stages of primary open-angle glaucoma. 120 patients (157 eyes) were treated using biologically controlled ultrasound therapy besides traditional medicamentous therapy, the remaining 40 ones (49 eyes) were given only conventional medication. Results of the treatment were evaluated based on a set of commonly used hydrodynamic and electrophysiological characteristics of the quality of visual function. Biologically controlled massage of trabecular structures of the affected eyes made it possible to stabilize and improve major hydrodynamic characteristics of the eyeball drainage system, visual function, and electrophysiological parameters. Biologically controlled ultrasound therapy proved to produce a more pronounced beneficial effect on ocular hydrodynamics than the traditional ultrasonic treatment. The positive action of biologically controlled therapy persisted during 8 months; its repeated sessions prolonged this period up to 2 years.

[Vascular risk factors in glaucoma - diagnostics]. / Vaskuläre Risikofaktoren beim Glaukom - Diagnostik.

The major risk factor for glaucoma is the increased intraocular pressure, and its pharmacological and/or surgical reduction slows down the progression of the glaucomatous damage. However, this protective effect is only a partial one, the complete arrest of damage progression does not take place, indicating risk factors other than intraocular pressure. Among vascular factors, reduced ocular perfusion pressure, in particular the nocturnal episodes of arterial hypotony, and the vascular dysregulation play important roles in glaucoma. Combined with variable intraocular pressure, these factors lead to oxidative stress, reperfusion damage and ultimately to the hallmark of glaucoma - loss of axons and tissue remodelling (cupping). Examination of vascular risk profile is necessary in order to tailor the therapy to the patients individual need.