Comparison of early posttreatment effects of two steroidal anti-inflammatory ophthalmic drugs on the ocular inflammatory response induced by paracentesis in healthy canine eyes.

OBJECTIVE: We investigated the early posttreatment effects of two steroidal anti-inflammatory ophthalmic drugs on blood-aqueous barrier (BAB) breakdown by paracentesis in dogs. ANIMAL STUDIES: We studied 21 healthy beagles with normal eyes. PROCEDURES: Controlled anterior chamber paracentesis (0.5 mL) was performed in one eye of each dog. Control group dogs (n = 7) received no medication, whereas those in the treatment groups received a topical anti-inflammatory medication (difluprednate [DFBA] ophthalmic emulsion 0.05% [n = 7] or betamethasone [BMZ] sodium phosphate ophthalmic solution 0.1% [n = 7]) at 0, 15, 30, and 45 minutes after initial paracentesis in the paracentesed eyes. Secondary aqueous humor (AH) was collected 60 minutes after initial paracentesis. Protein and prostaglandin E2 (PGE2 ) concentrations in AH were determined using the bicinchoninic acid assay and commercially available immunoassay kit, respectively. All mean values in the three groups were compared using analysis of variance followed by Tukey's post hoc test. RESULTS: Aqueous protein and PGE2 concentrations were markedly increased at 60 minutes following paracentesis. Both concentrations in the secondary AH of the DFBA group were significantly lower than those of the control group; however, treatment with BMZ had no significant effects. CONCLUSIONS: Early postparacentesis treatment with DFBA was more effective than that with BMZ for reducing aqueous protein and PGE2 contents in dogs with paracentesis-induced BAB breakdown. DFBA may be an appropriate treatment during the early stage of anterior uveitis caused by intraocular surgery in dogs.

Effect of oral administration of robenacoxib on inhibition of paracentesis-induced blood-aqueous barrier breakdown in healthy cats.

OBJECTIVE To determine the effect of oral administration of robenacoxib on inhibition of anterior chamber paracentesis (ACP)-induced breakdown of the blood-aqueous barrier (BAB) and assess whether robenacoxib can cross an intact BAB in healthy cats. ANIMALS 12 healthy adult domestic shorthair cats. PROCEDURES Cats received robenacoxib (6-mg tablet in a treat, PO; n = 6) or a control treatment (treat without any drug, PO; 6) once daily for 3 days, beginning 1 day before ACP. One eye of each cat served as an untreated control, whereas the other underwent ACP, during which a 30-gauge needle was used to aspirate 100 µL of aqueous humor for determination of robenacoxib concentration. Both eyes of each cat underwent anterior chamber fluorophotometry at 0 (immediately before), 6, 24, and 48 hours after ACP. Fluorescein concentration and percentage fluorescein increase were used to assess extent of ACP-induced BAB breakdown and compared between cats that did and did not receive robenacoxib. RESULTS Extent of BAB breakdown induced by ACP did not differ significantly between cats that did and did not receive robenacoxib. Low concentrations of robenacoxib were detected in the aqueous humor (mean, 5.32 ng/mL; range, 0.9 to 16 ng/mL) for 5 of the 6 cats that received the drug. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that oral administration of robenacoxib did not significantly decrease extent of BAB breakdown in healthy cats. Detection of low robenacoxib concentrations in the aqueous humor for most treated cats indicated that the drug can cross an intact BAB.

The Effects of IL-22 on the Inflammatory Mediator Production, Proliferation, and Barrier Function of HUVECs.

The aim of this study was to investigate the effects of interleukin (IL)-22 on proliferation function and inflammatory mediator production and barrier function of human umbilical vein endothelial cells (HUVECs). The expression of mRNA was detected by RT-PCR. The proliferation ability of cells was evaluated using a cell counting kit assay. Real-time quantitative PCR and Western blot were used to detect the expression of inflammatory mediators. The endothelial barrier permeability was assessed by measuring permeability to FITC-labeled dextran. The distribution of occludin was detected by immunofluorescence. IL-22R1 mRNA expression was noted in HUVECs. IL-22 could enhance the proliferation ability of HUVECs and suppress lipopolysaccharide (LPS)-induced proliferation inhibition in these cells. IL-22 also enhanced the production of CCL2 and CCL20 by HUVECs. Besides, IL-22 could improve barrier function and decrease LPS-induced increased cellular permeability and inhibit the LPS-induced destruction of occludin in HUVECs. IL-22 may play a protective role in the development of vasculitis.

Effects of topical adrenergic agents on prostaglandin E2-induced aqueous flare and intraocular pressure elevation in pigmented rabbits.

PURPOSE: To evaluate the effects of signals through adrenergic receptors on the changes in the aqueous flare and intraocular pressure (IOP) induced by topical prostaglandin E2 (PGE2) in pigmented rabbits. METHODS: Adrenergic agents were applied topically to pigmented Dutch rabbits, and PGE2 was then applied to induce an increase in the aqueous flare and IOP. The degree of aqueous flare was measured with a laser flare meter, and the IOP was measured with a rebound tonometer. Measurements were made every 30 min after the PGE2 had been applied for 2 h and at 4.0 and 4.5 h. Repeated measure analysis of variance and Dunnett's post hoc tests were used for the statistical analyses. RESULTS: The topical application of PGE-2 increased the aqueous flare for more than 4.5 h. The topical instillation of 1.0 % apraclonidine significantly inhibited the increase in the PGE2-induced aqueous flare by 75.1 %, of 0.1 % brimonidine by 57.2 %, of 0.04 % dipivefrin by 57.4 %, and a combination of 0.1 % brimonidine and 5 % phenylephrine by 78.9 %. Topical 5.0 % phenylephrine and 0.05 % isoproterenol had little effect on the aqueous flare elevation induced by PGE2. The IOP increased 0.5 h after the topical application of PGE-2. Topical 1.0 % apraclonidine, 0.1 % brimonidine, 0.1 % dipivefrin, and the combination of 0.1 % brimonidine and 5.0 % phenylephrine significantly inhibited the PGE2-induced IOP elevation. However, topical 5.0 % phenylephrine and 0.05 % isoproterenol did not significantly inhibit the IOP elevation caused by PGE2. CONCLUSIONS: Signaling by the α2 receptor inhibits both the PGE2-induced flare and IOP elevation caused by topical PGE2 application.

Effects of repeated Cr(VI) intratracheal instillation on club (Clara) cells and activation of nuclear factor-kappa B pathway via oxidative stress.

Hexavalent chromium [Cr(VI)] exposure is known to induce respiratory inflammation and contribute to lung cancer development, but little is known about its target cell type in lung. In the current study, we investigated the effects of repeated Cr(VI) intratracheal instillation on club (Clara) cells and club (Clara) cell secretory protein (CC16) in rats and explored whether the nuclear factor-kappa B (NF-κB) related pathway was involved. We also studied the role of orally delivered Zn against Cr-induced adverse health effects. For four weeks, sixty Sprague-Dawley male rats received weekly intratracheal instillation of potassium dichromate (K2Cr2O7) at 0, 0.063 and 0.630mgCr/kg with or without daily intragastric administration of zinc sulfate (ZnSO4) at 10mg Zn/kg. Results showed that exposure to Cr(VI) significantly increased the organ coefficient of lung (organ weight as a percentage of body weight), albumin and total protein level in bronchoalveolar lavage fluid (BALF), indicating lung injury and compromised bronchoalveolar/blood barrier (BA/BB) integrity. With increasing Cr(VI) dose, the secretion of CC16 decreased in a dose-dependent manner, suggesting that CC16 can serve as a peripheral biomarker for club cell damage during early lung injury induced by Cr(VI). Increased expression of NF-κB were observed in club cells in both Cr-exposed groups, indicating upregulation of NF-κB, which can be induced by reactive oxygen species (ROS) generated by club cells during Cr reduction with repetitive Cr(VI) exposure. Cr-induced DNA damage was also observed, as significant increase of 8-OHdG was found with Cr exposure at 0.630mg/kg week. Oral Zn supplementation did not alleviate changes in serum CC16 level under Cr(VI) exposure, indicating its failure in protecting against Cr(VI)-induced club cell damage.

Effects of benzalkonium chloride on the blood-aqueous and blood-retinal barriers of pseudophakic eyes.

PURPOSE: To evaluate the effects of benzalkonium chloride (BAK) on the blood-aqueous (BAB) and blood-retinal barriers (BRB) of pseudophakic eyes. METHODS: Prospective, randomized, investigator-masked, comparative study. Patients were randomly assigned to preservative-free artificial tears or BAK-preserved artificial tears. One drop of artificial tears was instilled 4 times a day in the study eye, starting the day after randomization for 30 days. Anterior chamber flare was assessed by a laser flare meter (LFM) and macular thickness measurements were obtained with optical coherence tomography, before, 15, and 30 days after randomization. RESULTS: A total of 44 healthy eyes of 44 pseudophakic volunteers were recruited. There were no significant differences regarding demographics (age, gender, and race distributions) and clinical characteristics (eye, mean intraocular pressure, and mean best-corrected visual acuity) between the 2 groups (P>0.05). No significant differences in baseline mean LFM values were observed (P=0.262). However, we detected a statistically significant increase in mean LFM measurements in the BAK-preserved group (11.4 ± 5.1 ph/ms) (P=0.017) after 15 days. After 30 days, the BAK-preserved group maintained significantly higher flare values (11.9 ± 5.9 ph/ms) compared with baseline (P=0.043). On the other hand, the preservative-free group showed mean flare values of 8.4 ± 2.5 ph/ms, not significantly different from those obtained at baseline (P=1.00). We observed no statistically significant change in macular thickness measurements at days 15 and 30 in either group (P>0.05). Cystoid macular edema was not detected in this series. CONCLUSIONS: Our results suggest that a short-term exposure to BAK can cause disruption of the BAB, without altering the BRB in pseudophakic eyes.

Cerebral protection: inflammation, endothelial dysfunction, and postoperative cognitive dysfunction.

PURPOSE OF REVIEW: Postoperative cognitive dysfunction (POCD) is a well recognized perioperative syndrome, with approximately 15% of patients over the age of 60 years displaying objectively measured decrease in cognitive function as a consequence of anesthesia and surgery. The exact cause, however, remains unknown. This review aims to update anesthesiologists on the recent advancements in the understanding of the pathophysiology of POCD. RECENT FINDINGS: Recent evidence suggests that the observed predilection to POCD is likely mediated by a neuro-inflammatory response - with surgery being a major contributing factor. The blood-brain barrier, a highly specialized endothelial layer, is exquisitely sensitive to an inflammatory insult and implicated in the cause of other neurocognitive syndromes also characterized by neuro-inflammation such as cerebral malaria. Inflammatory changes may disrupt the blood-brain barrier and facilitate migration of macrophages into the brain, damaging synapses and neurones and ultimately lead to POCD. This review explores the important question of causality - the potential relationship between inflammation, endothelial dysfunction, and postoperative cognitive decline. SUMMARY: Recent research points to a central role of a neuro-inflammatory cascade in POCD, with endothelial dysfunction potentially aggravating the insult. Investigating the genomic and molecular mechanisms that underlie the intervariation in the inflammatory response to surgery, improving the identification of appropriate endothelial and inflammatory biomarkers, and developing endothelial modulatory and anti-inflammatory (prevention and resolution) strategies are key areas of future translational research. This is important as the elderly, who show increased susceptibility to this and other perioperative illness syndromes, represent an ever-increasing proportion of patients presenting for surgery.

In vivo assessment of the permeability of the blood-brain barrier and blood-retinal barrier to fluorescent indoline derivatives in zebrafish.

BACKGROUND: Successful delivery of compounds to the brain and retina is a challenge in the development of therapeutic drugs and imaging agents. This challenge arises because internalization of compounds into the brain and retina is restricted by the blood-brain barrier (BBB) and blood-retinal barrier (BRB), respectively. Simple and reliable in vivo assays are necessary to identify compounds that can easily cross the BBB and BRB. METHODS: We developed six fluorescent indoline derivatives (IDs) and examined their ability to cross the BBB and BRB in zebrafish by in vivo fluorescence imaging. These fluorescent IDs were administered to live zebrafish by immersing the zebrafish larvae at 7-8 days post fertilization in medium containing the ID, or by intracardiac injection. We also examined the effect of multidrug resistance proteins (MRPs) on the permeability of the BBB and BRB to the ID using MK571, a selective inhibitor of MRPs. RESULTS: The permeability of these barriers to fluorescent IDs administered by simple immersion was comparable to when administered by intracardiac injection. Thus, this finding supports the validity of drug administration by simple immersion for the assessment of BBB and BRB permeability to fluorescent IDs. Using this zebrafish model, we demonstrated that the length of the methylene chain in these fluorescent IDs significantly affected their ability to cross the BBB and BRB via MRPs. CONCLUSIONS: We demonstrated that in vivo assessment of the permeability of the BBB and BRB to fluorescent IDs could be simply and reliably performed using zebrafish. The structure of fluorescent IDs can be flexibly modified and, thus, the permeability of the BBB and BRB to a large number of IDs can be assessed using this zebrafish-based assay. The large amount of data acquired might be useful for in silico analysis to elucidate the precise mechanisms underlying the interactions between chemical structure and the efflux transporters at the BBB and BRB. In turn, understanding these mechanisms may lead to the efficient design of compounds targeting the brain and retina.

Benzalkonium chloride induces anterior chamber inflammation in previously untreated patients with ocular hypertension as measured by flare meter: a randomized clinical trial.

PURPOSE: The deleterious effects of benzalkonium chloride (BAK) on the ocular surface are well known. However, few clinical data are available to prove a toxic effect at the level of the anterior chamber. The laser flare meter is a reliable tool to detect low levels of inflammation in the anterior chamber. We wanted to know whether instillation of BAK-preserved timolol in one eye would result in higher laser flare values than the instillation of preservative-free timolol in the fellow eye. METHODS: Randomized prospective, single-masked clinical trial. Twenty-eight untreated patients with ocular hypertension were recruited. After obtaining baseline flare values, we randomly assigned one eye to BAK-preserved timolol and the fellow eye to preservative-free timolol. After 1 month, flare measurements were repeated. RESULTS: There was a significant increase in the flare values in the two treatment regimens, but the increase in the BAK-treated eyes was higher than in the preservative-free treated eyes, and this difference in increase was statistically significant. CONCLUSION: This is the first study to show that short-term BAK administration produces inflammation in the anterior segment of previously untreated patients whose blood-aqueous barrier was not affected by recent intraocular surgery.

Systemic administration of urocortin after intracerebral hemorrhage reduces neurological deficits and neuroinflammation in rats.

BACKGROUND: Intracerebral hemorrhage (ICH) remains a serious clinical problem lacking effective treatment. Urocortin (UCN), a novel anti-inflammatory neuropeptide, protects injured cardiomyocytes and dopaminergic neurons. Our preliminary studies indicate UCN alleviates ICH-induced brain injury when administered intracerebroventricularly (ICV). The present study examines the therapeutic effect of UCN on ICH-induced neurological deficits and neuroinflammation when administered by the more convenient intraperitoneal (i.p.) route. METHODS: ICH was induced in male Sprague-Dawley rats by intrastriatal infusion of bacterial collagenase VII-S or autologous blood. UCN (2.5 or 25 µg/kg) was administered i.p. at 60 minutes post-ICH. Penetration of i.p. administered fluorescently labeled UCN into the striatum was examined by fluorescence microscopy. Neurological deficits were evaluated by modified neurological severity score (mNSS). Brain edema was assessed using the dry/wet method. Blood-brain barrier (BBB) disruption was assessed using the Evans blue assay. Hemorrhagic volume and lesion volume were assessed by Drabkin's method and morphometric assay, respectively. Pro-inflammatory cytokine (TNF-α, IL-1ß, and IL-6) expression was evaluated by enzyme-linked immunosorbent assay (ELISA). Microglial activation and neuronal loss were evaluated by immunohistochemistry. RESULTS: Administration of UCN reduced neurological deficits from 1 to 7 days post-ICH. Surprisingly, although a higher dose (25 µg/kg, i.p.) also reduced the functional deficits associated with ICH, it is significantly less effective than the lower dose (2.5 µg/kg, i.p.). Beneficial results with the low dose of UCN included a reduction in neurological deficits from 1 to 7 days post-ICH, as well as a reduction in brain edema, BBB disruption, lesion volume, microglial activation and neuronal loss 3 days post-ICH, and suppression of TNF-α, IL-1ß, and IL-6 production 1, 3 and 7 days post-ICH. CONCLUSION: Systemic post-ICH treatment with UCN reduces striatal injury and neurological deficits, likely via suppression of microglial activation and inflammatory cytokine production. The low dose of UCN necessary and the clinically amenable peripheral route make UCN a potential candidate for development into a clinical treatment regimen.

The effects of anthrax lethal toxin on host barrier function.

The pathological actions of anthrax toxin require the activities of its edema factor (EF) and lethal factor (LF) enzyme components, which gain intracellular access via its receptor-binding component, protective antigen (PA). LF is a metalloproteinase with specificity for selected mitogen-activated protein kinase kinases (MKKs), but its activity is not directly lethal to many types of primary and transformed cells in vitro. Nevertheless, in vivo treatment of several animal species with the combination of LF and PA (termed lethal toxin or LT) leads to morbidity and mortality, suggesting that LT-dependent toxicity is mediated by cellular interactions between host cells. Decades of research have revealed that a central hallmark of this toxicity is the disruption of key cellular barriers required to maintain homeostasis. This review will focus on the current understanding of the effects of LT on barrier function, highlighting recent progress in establishing the molecular mechanisms underlying these effects.

Evaluation of drug efflux transporter liabilities of darifenacin in cell culture models of the blood-brain and blood-ocular barriers.

AIMS: The objective of the present study was to evaluate drug efflux transporter interactions of darifenacin and examine the impact of such transporter interactions on darifenacin permeability in an in vitro model of the blood-brain barrier (BBB) and blood-ocular barrier (BOB). METHODS: Cell membranes expressing human P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP), and breast cancer resistance protein (BCRP) were examined for ATPase activity following darifenacin exposure (0-10 µM). Primary cultured bovine brain microvessel endothelial cells (BBMEC) and P-gp transfected Manin-Darby canine kidney epithelial cells (MDCKMDR1) were used to examine darifenacin permeability and drug efflux transporter responses. RESULTS: Concentration-dependent increases in ATPase activity was observed in P-gp membranes following darifenacin exposure. Both MRP and BCRP membrane preparations were unresponsive to darifenacin. Studies in both BBMEC and MDCKMDR1 monolayers confirmed a P-gp interaction for darifenacin and significantly greater efflux (basolateral to apical) permeability for darifenacin that was reduced by the P-gp inhibitor, elacridar. CONCLUSIONS: Darifenacin is a substrate for the P-gp drug efflux transporter present in both BBB and BOB. The P-gp drug efflux transporter liabilities of darifenacin may limit its penetration into brain and ocular tissue thereby reducing side effect potential.

Nepafenac 0.1% versus fluorometholone 0.1% for preventing cystoid macular edema after cataract surgery.

PURPOSE: To compare a topical nonsteroidal antiinflammatory drug (nepafenac 0.1%) and a topical steroidal antiinflammatory drug (fluorometholone 0.1% ) in preventing cystoid macular edema (CME) and blood-aqueous barrier (BAB) disruption after small-incision cataract extraction with foldable intraocular lens (IOL) implantation. SETTING: Shohzankai Medical Foundation, Miyake Eye Hospital, Nagoya, Japan. DESIGN: Randomized double-masked single-center clinical trial. METHODS: Patients were randomized to receive nepafenac 0.1% eyedrops or fluorometholone 0.1% eyedrops for 5 weeks after phacoemulsification with foldable IOL implantation. The incidence and severity of CME were evaluated by fluorescein angiography, retinal foveal thickness on optical coherence tomography, and BAB disruption on laser flare-cell photometry. RESULTS: Thirty patients received nepafenac and 29 patients, fluorometholone. Five weeks postoperatively, the incidence of fluorescein angiographic CME was significantly lower in the nepafenac group (14.3%) than in the fluorometholone group (81.5%) (P<.0001). The fovea was thinner in the nepafenac group than in the fluorometholone group at 2 weeks (P=.0266) and 5 weeks (P=.0055). At 1, 2, and 5 weeks, anterior chamber flare was significantly less in the nepafenac group than in the fluorometholone group (P<.0001, P<.0001, and P=.0304, respectively). The visual acuity recovery from baseline was significantly greater in the nepafenac group (80.0%) than in the fluorometholone group (55.2%) (P=.0395). There were no serious side effects in either group. CONCLUSION: Nepafenac was more effective than fluorometholone in preventing angiographic CME and BAB disruption, and results indicate nepafenac leads to more rapid visual recovery.

Evaluation of four drugs for inhibition of paracentesis-induced blood-aqueous humor barrier breakdown in cats.

OBJECTIVE: To compare inhibitory effects of topically applied 1% prednisolone acetate suspension, 0.03% flurbiprofen solution, 0.1% dexamethasone suspension, and 0.1% diclofenac solution on paracentesis-induced blood-aqueous barrier breakdown in cats. ANIMALS: 9 healthy cats. PROCEDURES: Paracentesis of the anterior chamber was performed in both eyes of each cat. One eye of each cat was treated with a topically administered anti-inflammatory medication (1% prednisolone [n = 7 cats], 0.03% flurbiprofen [7], 0.1% dexamethasone [9], or 0.1% diclofenac [8]) immediately following paracentesis and at 6, 10, and 24 hours after paracentesis. The contralateral untreated eye served as the control eye. Each cat had a 6-day washout period between experimental drugs. Breakdown of the blood-aqueous barrier was quantified by use of laser flaremetry. RESULTS: Topical administration of 1% prednisolone significantly reduced aqueous humor flare at 4, 8, and 26 hours after paracentesis. Topical administration of 0.1% diclofenac significantly reduced aqueous humor flare at 8 and 26 hours after paracentesis. Topical administration of 0.1% dexamethasone and 0.03% flurbiprofen did not significantly decrease flare at any time point. There were significant differences in intraocular pressures between NSAID-treated eyes and untreated contralateral eyes. CONCLUSIONS AND CLINICAL RELEVANCE: Topical administration of 1% prednisolone and 0.1% diclofenac significantly reduced intraocular inflammation in cats with paracentesis-induced uveitis. Topical administration of 1% prednisolone or 0.1% diclofenac may be appropriate choices when treating cats with anterior uveitis. Topical administration of diclofenac and flurbiprofen should be used with caution in cats with a history of ocular hypertension.

Effect of menthol on ocular drug delivery.

BACKGROUND: To assess how safe and effective it is to use menthol as a permeability enhancer in ophthalmic drug delivery systems. METHODS: In this study, the effect of menthol on permeability of dexamethasone disodium phosphate in the cornea and sclera was investigated in vitro. Application of topical drops and subconjunctival injection of dexamethasone disodium phosphate with or without 0.1% menthol was administered to rabbit eyes, and the drug concentration was detected in aqueous humor, cornea, vitreous, and retinochoroidal tissues. The safety of menthol was assessed on the basis of corneal hydration level, Draize test, electroretinography (ERG), and histological examination. RESULTS: 0.05% and 0.1% menthol significantly enhanced the penetration of dexamethasone in the cornea, but did not change the dexamethasone penetration in sclera in vitro. When topical drops of dexamethasone containing 0.1% menthol were administered, a significantly increased concentration of dexamethasone in the cornea and aqueous humor tissues was reported, but dexamethasone concentrations remained unaffected in the retina-choroid tissues. On the other hand, increased drug concentration in aqueous humor, cornea, vitreous and retinochoroidal tissues was achieved through subconjunctival injection. No signs of irritation were observed when menthol was administered at concentrations ranging from 0.025%-0.1%; moreover, no substantial toxic reactions were observed in corneal hydration level, electrophysiological, or histological examinations after the addition of 0.1% menthol. CONCLUSIONS: Menthol may improve the ocular penetration of a drug in a transcorneal and transscleral drug delivery system without causing toxic reactions.

Inhibitory effects of alcohol on glucose transport across the blood-brain barrier leads to neurodegeneration: preventive role of acetyl-L: -carnitine.

PURPOSE: Evidence shows that alcohol intake causes oxidative neuronal injury and neurocognitive deficits that are distinct from the classical Wernicke-Korsakoff neuropathy. Our previous findings indicated that alcohol-elicited blood-brain barrier (BBB) damage leads to neuroinflammation and neuronal loss. The dynamic function of the BBB requires a constant supply and utilization of glucose. Here we examined whether interference of glucose uptake and transport at the endothelium by alcohol leads to BBB dysfunction and neuronal degeneration. MATERIAL AND METHODS: We tested the hypothesis in cell culture of human brain endothelial cells, neurons and alcohol intake in animal by immunofluorescence, Western blotting and glucose uptake assay methods. RESULTS: We found that decrease in glucose uptake correlates the reduction of glucose transporter protein 1 (GLUT1) in cell culture after 50 mM ethanol exposure. Decrease in GLUT1 protein levels was regulated at the translation process. In animal, chronic alcohol intake suppresses the transport of glucose into the frontal and occipital regions of the brain. This finding is validated by a marked decrease in GLUT1 protein expression in brain microvessel (the BBB). In parallel, alcohol intake impairs the BBB tight junction proteins occludin, zonula occludens-1, and claudin-5 in the brain microvessel. Permeability of sodium fluorescein and Evans Blue confirms the leakiness of the BBB. Further, depletion of trans-endothelial electrical resistance of the cell monolayer supports the disruption of BBB integrity. Administration of acetyl-L: -carnitine (a neuroprotective agent) significantly prevents the adverse effects of alcohol on glucose uptake, BBB damage and neuronal degeneration. CONCLUSION: These findings suggest that alcohol-elicited inhibition of glucose transport at the blood-brain interface leads to BBB malfunction and neurological complications.

Temporary intraocular pressure lowering by photodynamic therapy in pseudoexfoliation glaucoma.

BACKGROUND AND OBJECTIVE: the aim of the study was to ascertain whether photodynamic therapy (PDT) with verteporfin is able to reduce the blood-aqueous barrier impairment in eyes affected by pseudoexfoliative glaucoma (PESG) with consequent intraocular pressure (IOP) lowering. PATIENTS AND METHODS: five patients with poorly controlled PESG were selected. The laser energy was directed to the anterior chamber angle and the iris surface by means of a Goldmann lens. RESULTS: IOP reduction was registered 1 month after PDT and lasted 3 months, reaching the values registered before PDT after that. Iris fluorescein angiography 1 week and 1 month after PDT showed reduced dye leakage, but the same amount of dye leakage visible before PDT was detectable 3 months later. CONCLUSION: PDT can reduce the breakdown of the blood-aqueous barrier and can lower the IOP temporarily in eyes affected by PESG. Further studies are needed to analyze the biochemical changes after PDT in aqueous humor.

Calcium channel blocker nilvadipine, but not diltiazem, inhibits ocular inflammation in endotoxin-induced uveitis.

PURPOSE: Calcium channel blockers (CCBs), widely used for hypertensive patients, have recently been shown to inhibit atherosclerosis by their antioxidative action. The aim of the present study was to examine whether the CCBs nilvadipine and diltiazem reduce ocular inflammation in endotoxin-induced uveitis (EIU). METHODS: EIU was induced in male C57/B6 mice with a single intraperitoneal injection of lipopolysaccharide (LPS). The animals received intraperitoneal injections of either nilvadipine, diltiazem, or vehicle for 5 days before the LPS application. Twenty-four hours after EIU induction, adherent leukocytes to the retinal vasculature were counted with a concanavalin A lectin perfusion-labeling technique. The protein concentration in the aqueous humor was measured to assess blood-ocular barrier breakdown. Retinal levels of intercellular adhesion molecule (ICAM)-1 and monocyte chemotactic protein (MCP)-1 were analyzed by enzyme-linked immunosorbent assay. LPS-stimulated generation of superoxide in murine microvascular endothelial cells was examined with a nitroblue tetrazolium assay. RESULTS: Compared to vehicle treatment, application of nilvadipine, but not diltiazem, led to significant suppression of EIU-associated retinal leukocyte adhesion, together with anterior-chamber protein leakage, retinal expression of ICAM-1 and MCP-1, and LPS-induced superoxide generation in vitro. CONCLUSIONS: The CCB nilvadipine exercises an inhibitory effect on the pathogenesis of ocular inflammation through the suppression of inflammation-related molecules.

Drug delivery to the posterior segment of the eye.

Drug delivery into the posterior segment of the eye is complicated by the existence of the blood-ocular barrier. Strategies for delivering drugs to the posterior segment include systemic administration, modification of the barrier, and local drug delivery (including transcorneal, transscleral, and intravitreal). Recently, new topical treatments have emerged for the treatment of posterior eye disease. Iontophoretic, juxtascleral, and intravitreal routes can be used to achieve therapeutic levels in the posterior segment. Extended-release intravitreal drug delivery systems can achieve sustained therapeutic levels with the goal of providing a prolonged clinical benefit.

Effect of borneol on the distribution of danshensu to the eye in rabbit via oral administration.

PURPOSE: Both borneol and danshensu are bioactive substances derived from traditional Chinese medicine. In this paper, the effect of borneol on the distribution of danshensu to the eyes in rabbits via oral administration was investigated. METHODS: The rabbits were injected danshensu (1.0 g/kg) into the auris dextra vein 15 min after intragastric administration of borneol and the danshensu concentrations in plasma, aqueous humor, and vitreous humor were measured by high-performance liquid chromatography. Draize test was used to examine the eye irritation. RESULTS: Compared with the administration of danshensu alone, danshensu concentrations co-administrated with borneol in plasma were between 60.99 and 722.90 microg/ml. Peak times (T(max)) in both groups appeared at 0 min; however, compared with the control group, the values were not statistically significant although they differ (P > 0.05). The concentrations of danshensu in aqueous humor and vitreous humor in test group are higher than that in control group. The difference was statistically significant (P < 0.05). T(max) in both groups appeared at 25 min. Neither irritation nor inflammatory reaction was found during the examinations. CONCLUSION: The results suggest that the promoting effect of borneol on the permeability of drugs through the blood-ocular barrier in vivo is obvious, which indicates that borneol has the potential to be used as an ocular penetration enhancer.