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Purpose: To report the occurrence probability of disc haemorrhage (DH) and risk factors for it in otherwise healthy Japanese normal‐tension glaucoma (NTG) patients who had lower normal intraocular pressure (IOP) and were followed without treatment for 5 years. Methods: A prospective observational study. Normal‐tension glaucoma (NTG) patients with IOP consistently ≤15 mmHg without treatment were enrolled. The presence or absence of DH was checked semi‐annually on the fundus photographs by three independent observers, while patients were followed without treatment. Cox proportional hazards model taking inter‐eye correlation into consideration was adopted to identify risk factors for DH occurrence. The main outcomes were DH occurrence probability during 5‐year period and its risk factors. Results: One hundred seventeen eyes of 90 patients with mean age of 54.1 years, mean deviation value of −3.6 decibels and mean IOP during follow‐up of 12.4 mmHg were included. Disc haemorrhage (DH) was observed at least once in 34 eyes and more than twice in 15 eyes during the follow‐up. The DH occurrence probability at 5 years was 31% (95% confidence interval: 21–40%), and lower myopic refraction (HR = 1.18; p = 0.018), higher IOP during follow‐up (HR = 1.35; p = 0.047) and presence of DH at baseline (HR = 4.19; p = 0.002) were its risk factors. Conclusion: Disc haemorrhage (DH) occurrence probability of Japanese healthy NTG patients with mean IOP of 12.4 mmHg and no systemic and/or topical treatment was 31% at 5 years. Lower myopic refraction, higher IOP and its existence at baseline were its risk factors. [ABSTRACT FROM AUTHOR]

To characterize the natural history and define the risk factors associated with the progression of normal-tension glaucoma (NTG) in Japanese patients who were followed up closely without treatment. Prospective 5-year study. Patients with NTG with intraocular pressure (IOP) consistently ≤15 mmHg without treatment at baseline. Visual field (VF) examinations were performed every 3 months, and disc/peripapillary retina photographs were taken every 6 months. Patients were followed up without treatment. Deterioration in VF was defined by reference to Guided Progression Analysis Software of the Humphrey VF Swedish Interactive Thresholding Algorithm 24-2 (Carl Zeiss Meditec, Jena, Germany) and disc/peripapillary retina deterioration as adjudged by 3 independent observers. Life table analysis was used for evaluating the time to disease progression, as defined by VF or deterioration of the optic nerve head structure. The Cox proportional hazards model was used to identify risk factors for glaucoma progression. We enrolled 90 patients (mean age, 53.9 years; baseline IOP, 12.3 mmHg; mean deviation [MD], −2.8 decibels [dB]). The MD slope averaged −0.33 dB/year (median, −0.23; 95% confidence interval [CI], −0.44 to −0.22). Glaucoma progression probability at 5 years was 66% (95% CI, 55–78), as defined by VF deterioration or disc/peripapillary retina deterioration (criterion 1): 52% (95% CI, 37–60), as defined by VF deterioration (criterion 2), and 50% (95% CI, 38–71), as defined by disc/peripapillary retina deterioration (criterion 3). Presence or history of disc hemorrhage (DH) (P < 0.001), long-term IOP fluctuation (P = 0.020), and a greater vertical cup-to-disc ratio (v-C/D) (P = 0.018) were significant predictors for progression defined by criterion 1. Long-term IOP fluctuation (P = 0.011) and a greater v-C/D (P = 0.036) were significant predictors for progression by criterion 2. Presence or history of DH (P = 0.0018) and long-term IOP fluctuation (P = 0.022) were significant predictors for progression by criterion 3. In Japanese patients with NTG with mean baseline IOP of 12.3 mmHg without treatment, estimated mean MD slope for 5 years was –0.33 dB/year; probability of glaucoma progression based on VF or disc/peripapillary end points at 5 years was 66%. Presence or history of DH, long-term IOP fluctuation, and greater v-C/D significantly contributed to progression. [ABSTRACT FROM AUTHOR]

We previously reported that elevated pressure induces axonal swelling and facilitates the synthesis of the neurosteroid, allopregnanolone (AlloP), in the ex vivo rat retina. Exogenously applied AlloP attenuates the axonal swelling, suggesting that the neurosteroid plays a neuroprotective role against glaucomatous pressure-induced injuries, although mechanisms underlying neurosteroidogenesis have not been clarified. The aim of this study was to determine whether AlloP synthesis involves activation of translocator protein 18 kD (TSPO) and whether TSPO modulates pressure-induced retinal injury. Ex vivo rat retinas were exposed to various pressures (10, 35, or 75 mmHg) for 24 h. Expression of TSPO, 5α-reductase (5aRD), and AlloP was examined by quantitative real-time RT-PCR, ELISA, immunohistochemistry, and LC-MS/MS. We also examined the effects of TSPO ligands on AlloP synthesis and retinal damage. In this acute model, quantitative real-time RT-PCR and ELISA analyses revealed that elevated pressure facilitated TSPO expression. Similarly, these methods also detected enhanced 5aRD (mostly type II), which was observed in retinal ganglion cells (RGC) and the inner nuclear layer (INL). Atriol, a TSPO antagonist, suppressed pressure mediated AlloP synthesis and induced more severe histological changes in the inner retina when combined with elevated pressure. PK11195, a TSPO ligand that facilitates AlloP synthesis by itself, remarkably diminished pressure-mediated retinal degeneration. These results suggest that AlloP synthesis is induced by sequential activation of TSPO and 5aRD in an ex vivo glaucoma model, and that TSPO agonists may serve as potential therapeutic agents for the prevention of pressure-induced retinal damage. [ABSTRACT FROM AUTHOR]

A wide variety of animal models have been used to study glaucoma. Although these models provide valuable information about the disease, there is still no ideal model for studying glaucoma due to its complex pathogenesis. Animal models for glaucoma are pivotal for clarifying glaucoma etiology and for developing novel therapeutic strategies to halt disease progression. In this review paper, we summarize some of the major findings obtained in various glaucoma models and examine the strengths and limitations of these models. [ABSTRACT FROM AUTHOR]

Purpose : To investigate the effects of prostaglandin (PG) E 1 , E 2 , F 2α , and latanoprost acid on the electrically evoked contractile response of isolated rhesus monkey ciliary muscle. Methods : Longitudinal ciliary muscle preparations from rhesus monkeys were mounted in an organ bath, and tension changes were recorded by an isometric transducer. Electrical field stimulation (100 Hz, 0.3 ms, 10 V) was applied through a pair of platinum plate electrodes. Results : The ciliary muscle produced atropine-sensitive excitatory contraction in response to field stimulation. PGE 1 and PGE 2 (1 μ M) attenuated the contraction to levels that were 68% and 65.1%, respectively, of the normal amplitude. However, PGF 2α and latanoprost acid (1 μ M) did not significantly change the response amplitude. Conclusions : Our results indicate that PGF 2α and latanoprost acid do not interact with the prostanoid receptor involved at the pre- and/or postsynaptic site. Therefore, it is unlikely that the hypotensive action by these agents is due to relaxation of the ciliary muscle. [ABSTRACT FROM AUTHOR]

Abstract: Biologically active peptides modulate pupillary responsiveness in many non-primate mammals. We examined the action of seven different peptides on iris sphincter and dilator muscles of rhesus monkey. Iris sphincter and dilator muscle preparations from rhesus monkeys were mounted in an organ bath, and tension changes were recorded by an isometric transducer. Electrical field stimulation (100Hz, 0·3msec, 10V) was applied through a pair of platinum plate electrodes. Monkey iris sphincter and dilator muscles produced simple cholinergic and adrenergic excitatory responses respectively to electrical field stimulation. Strong field stimulation did not elicit slow Substance P (SP) mediated contractions like those in rabbit iris sphincter. Exogenously applied pituitary adenylate cyclase-activating peptide (PACAP) enhanced in a concentration-dependent manner (0·3nM–0·1μm) the sphincter response to field stimulation, while neuropeptide Y (NPY) and somatostatin (SRIF) attenuated it. These three peptides did not affect sphincter contractions induced by acetylcholine, and therefore were acting at presynaptically. SP, calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP) and galanin (GAL) had no effect (at 0·1μm) on iris sphincter. None of seven exogenously applied peptides had an effect on monkey iris dilator muscle. The innervation of primate irises may be relatively simple compared to non-primates because each of the peptides in this study can modulate miosis or mydriasis in non-primate mammals. Future studies will be expected on the functional significance of species differences in iridial innervation. [Copyright &y& Elsevier]

Purpose. To clarify the vasodilator mechanism of unoprostone isopropyl (unoprostone), a PG F2α related compound used for treatment of glaucoma, we have investigated the effect of this drug and its metabolites on isolated rabbit ciliary artery in vitro. Methods. Under the dissecting microscope, ciliary arteries were prepared from albino rabbit eyes and mounted in a mayo-graph system. The effects of unoprostone isopropyl and other agents were investigated using isometric tension recording methods. Results. Unoprostone induced a dose-dependent relaxation in ciliary arteries that were pre-contracted with high-K solution, 10μM histamine or 10μM PG F2α. Neither unoprostone metabolite M1 or M2 had a relaxant effect on the reconstructed vessels. Relaxation was unaffected by inhibition of ardently cycles with SQ 22536, guanylyl cyclase with ODQ, or maxi-K channels with iberiotoxin. Pretreatment with unoprostone did not affect histamine-induced transient contractions in Ca2+ -free solution. However. SKF9365. a general Ca2+ channel blocker. evoked relaxation similar to unoprostone with respect to amplitude and rate of onset. Conclusions. Unoprostone, but not its metabolites M1 and M2, relaxed pre-contracted rabbit ciliary artery. The mechanism of vascular smooth muscle relaxation by unoprostone differs from that of IOP reduction and does not depend on adenylyl cyclase, guanylyl cyclase, or maxi-K channels. Relaxation may be mediated by inhibition of Ca2+ entry, possibly through capacitative Ca2+ channels. [ABSTRACT FROM AUTHOR]

The neuropeptides somatostatin and galanin are present in the iris and may modulate pupil diameter. We examined the effects of somatostatin and galanin on isolated rabbit iris dilator and sphincter smooth muscles that were mounted in an organ bath. An isometric transducer recorded changes in tension in response to electric field stimulation (100 Hz, 0.3 m sec in duration, 10 V in strength) delivered by a pair of platinum plate electrodes. The dilator muscle response to field stimulation was not changed by either peptide, even at the highest concentrations examined. The sphincter muscle response consisted of two components: a fast component mediated by acetylcholine and slow component mediated by substance P. Both somatostatin and galanin attenuated the cholinergic component in a dose-dependent manner (from 0.3 nm to 0.1 μm) but had no effect on responses mediated by substance P. Galanin was more effective (attenuation of 43% at 0.1 μm) compared with somatostatin (attenuation of 16% at 0.1 μm) in reducing the cholinergic response. Neither peptide affected the contraction induced by acetylcholine (1 mm). Therefore both peptides inhibited cholinergic transmission in the sphincter muscle, although the degree of inhibition by each was different. We conclude that somatostatin and/or galanin may induce mydriasis by attenuating cholinergic neurotransmitter release. [Copyright &y& Elsevier]

The study focuses on obtaining the visco-elastic properties of the iris sphincter and dilator muscles. Two kinds of experiments were performed: the isometric contraction experiment and the isotonic quick release experiment. The length–tension relationship was obtained from the former experiment. This relationship clarified the contribution of each muscle in determining the statics of the pupil. The viscous and serial elastic properties were obtained from the latter experiment. The viscosity could be expressed by the expanded Hill’s equation as a function of velocity and contractile tension. We argue that serial elasticity is independent of contractile tension. These properties provide insights into the pupillary mechanism. [Copyright &y& Elsevier]

Nipradilol is a new antiglaucoma ophthalmic agent used in Japan. Topical application of nipradilol is reported to increase ocular blood flow. To investigate the action of this drug, we studied the effect of nipradilol on the isolated rabbit ciliary artery. Under the dissecting microscope, ciliary arteries were prepared from rabbit eyes and mounted on a myograph system. The effects of nipradilol on the isolated rabbit ciliary artery were investigated using isometric tension recording methods. Nipradilol provoked a dose-dependent (10 μM–1 m M) relaxation in ciliary arteries that were pre-contracted with high-K solutions (K+: 100.7 m M). It also inhibited the amplitude of smooth muscle contraction evoked by field stimulation. Nipradilol was more effective in relaxing phenylephrine-induced contraction (EC50: 21.6 ± 16.3 μM) compared to high-K solution-induced contractions (EC50: 230 ± 130 μM). Application of Nw-nitro- L -arginine methylester (300 μM), a nitric oxide (NO) synthase inhibitor, or denudations of endothelium by rubbing the inner surface with a scalp hair did not affect this relaxation. However, NO scavenger carboxy-PTIO (1 m M) or methylene blue (10 μM), a guanylate cyclase inhibitor, inhibited the nipradilol-induced relaxation. These results indicate that nipradilol relaxes the rabbit ciliary artery by two different mechanisms. First, the relaxation is due to the NO produced by denitrification of nipradilol itself. Second, nipradilol may act as an α-adrenergic antagonist. These actions of nipradilol may explain the mechanisms of increased ocular blood flow in vivo. [Copyright &y& Elsevier]

PURPOSE. A disturbance in ocular blood flow is an important factor in the pathogenesis of visual damage caused by glaucoma. We investigated the innervation of the ciliary artery, important to blood flow in the optic nerve head, and the effects of pilocarpine thereon. METHODS. Ciliary arteries were prepared from rabbit eyes and mounted in a myograph system. The effects of electrical nerve stimulation and pilocarpine on the isolated rabbit ciliary artery were investigated using isometric tension recording methods. RESULTS. Electrical field stimulation evoked contraction of the ciliary artery, which was inhibited by pretreatment with 10 μM bunazosin. Electrical field stimulation also evoked relaxation when the ciliary artery was pre-contracted by 10 μM histamine in the presence or absence of endothelium. This relaxation was inhibited by pretreatment with 10 μM NG-nitro-L-arginine methylester (L-NAME). Pilocarpine administration produced a dose-dependent muscle relaxation that was abolished by treatment with L-NAME, 1 æM atropine, or denudation of the endothelium. CONCLUSIONS. Results indicate that the rabbit ciliary artery is innervated by at least two different types of nerves, adrenergic nerves, which evoke contraction and nerve fibers that cause an endothelium-independent release of nitric oxide (NO). Pilocarpine relaxation of this muscle was dependent on the endothelium and NO synthesis. [ABSTRACT FROM AUTHOR]

In a rat ex vivo acute glaucoma model, high pressure (75 mmHg) causes swelling of ganglion cell axons and elevates levels of the endogenous steroids 24(S)-hydroxycholesterol (24SH) and allopregnanolone (AlloP). Furthermore, 24SH (0.1 µM) alone elevates AlloP levels via NMDA receptors. With this model, we now investigate possible interactions between 24SH and AlloP. We found that inhibition of AlloP synthesis with dutasteride under high pressure results in severe excitotoxicity in addition to axonal swelling. The excitotoxicity is prevented by exogenous AlloP but not 24SH, indicating that endogenous AlloP is crucial for protection. However, inhibition of 24SH synthesis with voriconazole induces severe excitotoxicity under normal pressure. Paradoxically, the excitotoxicity by voriconazole is better prevented by AlloP than 24SH. These findings suggest that inhibition of 24SH synthesis becomes excitotoxic in the absence of AlloP. We also observed that co-administration of sub-micromolar 24SH (0.1 µM) and AlloP (0.1 µM), concentrations that are only partially effective when administered alone, prevents axonal swelling under high pressure. This apparent enhanced protection indicates strong interaction between the two neurosteroids to preserve neuronal integrity, with 24SH contributing to AlloP synthesis via NMDA receptors and with AlloP playing an essential role in neuroprotection via GABAA receptors. [ABSTRACT FROM AUTHOR]

Purpose To investigate characteristics of lamina cribrosa (LC) defects in myopic eyes with open-angle glaucoma (OAG) using spectral-domain (SD) optical coherence tomography (OCT). Design Cross-sectional study. Participants One hundred thirty-three eyes with OAG and 83 eyes without OAG, with axial length of 24 mm or more. Methods Serial enhanced depth imaging SD OCT B-scans of the optic disc were acquired and reviewed for LC defects (diameter, ≥100 μm) and large pores (diameter, 60–100 μm). The numbers and locations of LC defects and large pores in each eye were assessed. In eyes with OAG, factors related to the number of LC defects were evaluated, as well as the association between the locations of LC defects and visual field (VF) defects (e.g., paracentral scotoma [PCS] and superior or inferior hemifield defects). Main Outcome Measures Numbers and locations of LC defects and large pores. Results In myopic eyes with and without OAG, the average numbers of LC defects were 3.8 and 0.8 and numbers of large pores were 1.9 and 1.6, respectively. In both groups, LC defects and large pores were located predominantly at the temporal periphery. Among eyes with OAG, the number of LC defects was relatively high in the eyes with greater optic disc tilt angle and worse mean deviation of the VF (both P < 0.001). The number of temporal LC defects and tilt angle were associated with presence of PCS, whereas the number of inferior and superior LC defects and torsion direction were associated with presence of superior and inferior VF defects. Conclusions Myopic eyes with OAG exhibited LC defects and large pores at similar locations as those without OAG, but in greater numbers, suggesting that these focal alternations of the LC in myopic eyes may evolve into larger defects when glaucoma develops in the eye. The number of LC defects, which was related to the optic disc tilt angle, was associated significantly with glaucomatous VF defects in both severity and location. This suggests that myopia may influence glaucomatous VF defects through optic disc tilt by way of an increased number of LC defects at the temporal periphery. [ABSTRACT FROM AUTHOR]

Purpose: Ripasudil, a Rho-associated coiled-coil-containing protein kinase (ROCK) inhibitor, is a novel drug for glaucoma in Japan. ROCK inhibition not only reduces intraocular pressure (IOP) but also increases ocular blood flow. We investigated the effects of ripasudil on optic disc blood flow (ODBF) in rabbit eyes and in isolated rabbit ciliary arteries. Methods: We measured IOP by tonometry and ODBF by laser speckle flowgraphy (LSFG) in male Dutch rabbits. A single drop (20 μL) of 0.8% ripasudil was delivered to the ocular surface after topical application of phenylephrine hydrochloride to reduce the ODBF. The effects of ripasudil on isolated rabbit ciliary artery smooth muscle contractions were measured in vitro with a myograph. Results: Ripasudil inhibited the reduction of ODBF induced by phenylephrine at 30 and 120 min after instillation ( P < .05). The blood flow change was not significantly correlated with the IOP change. Ripasudil induced a concentration-dependent relaxation in isolated rabbit ciliary arteries precontracted with a high-potassium solution. This relaxation was not mediated through the endothelium-dependent activities of nitric oxide synthase, prostacyclin, or the large-conductance calcium-activated K channel as shown by the inability of specific inhibitors of these pathways to block the ripasudil-induced relaxation. Conclusions: Taken together, our results showed that ripasudil not only decreased IOP but also increased ODBF in rabbits. However, the changes in IOP were not correlated with the changes in ODBF. Ripasudil also induced a concentration-dependent relaxation of isolated rabbit ciliary arteries through a NO-independent mechanism. Further investigation of the effect of ripasudil on ODBF is needed. [ABSTRACT FROM AUTHOR]

We measured the intraocular pressure (IOP), blood pressure (BP), heart rate (HR), and SFCT of the left eye of 54 healthy volunteers (22 men and 32 women; mean age, 21.4 ± 3.7 years) with a best-corrected visual acuity >= 20/20, mean body mass index (BMI) of 20.8 ± 2.4 kg/m SP 2 sp (range, 15.4-29.8 kg/m SP 2 sp ), and no ophthalmic, cardiovascular, or systemic disease. The mean BP (MBP) and ocular perfusion pressure (OPP) were determined from the IOP and BP. [Extracted from the article]

Purpose: The current study aimed to investigate the time course of changes in choroidal circulation hemodynamics and their relationship to systemic circulation dynamics during the normal menstrual cycle in young, healthy women using laser speckle flowgraphy (LSFG). Methods: This prospective study included 26 eyes from 13 young, healthy women (21.3 ± 4.0 years) with a normal menstrual cycle and 24 eyes from 12 young, healthy men (21.8 ± 4.4 years) as a control group. The macular mean blur rate (MBR), a quantitative index of relative blood flow velocity in the choroid, was measured using LSFG. MBR, intraocular pressure (IOP), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), and ocular perfusion pressure (OPP) were evaluated in the late follicular phase and mid-luteal phase in women and at baseline and 10 days after baseline in men, respectively. Results: In the female group, IOP, SBP, DBP, MBP, and OPP values were significantly higher in the mid-luteal phase than those observed in the late follicular phase (P = 0.035, P < 0.001, P = 0.041, P = 0.001, P = 0.014, respectively). The average macular MBR values in the late follicular phase and mid-luteal phase were 12.7 ± 5.3 and 13.7 ± 6.6 (+7.7 ± 19.4%), representing a significant increase in the mid-luteal phase (P = 0.041). The rate of change in MBR exhibited a significant positive correlation with changes in DBP and MBP (R = 0.456, P = 0.019 and R = 0.474, P = 0.014). However, there were no significant changes in any of the factors in the male group during the study period. Conclusions: Our results suggest that in young, healthy women with a normal menstrual cycle, choroidal blood flow velocity decreases during the late follicular phase and increases during the mid-luteal phase, depending on systemic circulatory dynamics. [ABSTRACT FROM AUTHOR]

The interphotoreceptor matrix (IPM) is a highly organized structure with interconnected domains surrounding cone and rod photoreceptor cells and extends throughout the subretinal space. Based on known roles of the extracellular matrix in other tissues, the IPM is thought to have several prominent functions including serving as a receptor for growth factors, regulating retinoid transport, participating in cytoskeletal organization in surrounding cells, and regulation of oxygen and nutrient transport. In addition, a number of studies suggest that the IPM also may play a significant role in the etiology of retinal degenerative disorders. In this review, we describe the present knowledge concerning the structure and function of the IPM under physiological and pathological conditions. [ABSTRACT FROM AUTHOR]

Purpose: In normotensive eyes, reduced ocular blood flow can lead to glaucoma pathogenesis. Drugs that reduce intraocular pressure (IOP) often cause vasodilation of the ciliary arteries and improve blood flow to the eye. A novel class of drugs called Rho-associated coiled coil-forming protein kinase (ROCK) inhibitors can lower IOP. Therefore, we tested the ability of two ROCK inhibitors, Y-27632 and Y39983, to relax rabbit ciliary arteries. Methods: We measured in vitro ciliary artery smooth muscle contractions by isometric tension recordings and changes of intracellular free calcium concentration ([Ca]) by fluorescence photometry. Results: Both Y-27632 and Y-39983 induced a concentration-dependent relaxation in rabbit ciliary arteries precontracted with a high-potassium (high-K) solution. The amplitude of relaxation induced by Y-27632 and Y-39983 was not affected by either 100 μM N-nitro- l-arginine methyl ester ( l-NAME) or 10 μM indomethacin. In Ca-free solution, Y-27632 and Y-39983 significantly inhibited the transient contraction of ciliary arteries induced by 10 μM histamine. However, neither Y-27632 nor Y-39983 affected the elevation of [Ca] induced by high-K solution and histamine. Conclusions: We concluded that Y-27632 and Y-39983 relaxed isolated rabbit ciliary artery segments in vitro. The mechanism of relaxation was not dependent on endothelial-derived factors such as nitric oxide (NO) or prostacyclin, nor was it dependent on changes in intracellular Ca concentration. [ABSTRACT FROM AUTHOR]

Purpose: To investigate peripapillary choroidal thickness (PPCT) in normal Japanese subjects by using spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging (EDI) technique and evaluate its association with ocular and systemic factors. Study Design: Cross-sectional study. Methods: This study included 85 eyes of 85 normal Japanese subjects. Normal subjects were defined as those without retinal and optic nerve disorders of any kind. The PPCT was measured at the location of 3.4 mm diameter peripapillary circle centered on the optic nerve head. It was measured as the distance between the retinal pigment epithelium and scleral-choroidal interface at the following six sectors; temporal, supra-temporal, supra-nasal, nasal, infero-nasal, and infero-temporal. Global PPCT was calculated based on these sectorial data. In addition, association between the PPCT and ocular and systemic factors were evaluated. Results: Among the included subjects, 39 (45.9%) were men and mean age was 51.4 ± 17.6 years. The mean global PPCT was 135.8 ± 40.6 µm. The infero-nasal and infero-temporal sectors were significantly thinner than other sectors (all, P < 0.05). In multiple regression analysis, thinner global PPCT was significantly associated with older age (P < 0.0001) and female sex (P = 0.0330) after considering effects of other confounders. Conclusions: This study provided global PPCT and its profile in normal Japanese subjects by using EDI SD-OCT. These results may be used as a reference in the assessment of normal status of the PPCT. The age and sex of the subjects should be considered in interpreting the PPCT data. [ABSTRACT FROM AUTHOR]

Discusses pupil perimetry and Humphrey field analysis in Leber hereditary optic neuropathy compared with optic neuritis. Quantitative analysis conducted in the superotemporal, superonasal, inferotemporal and inferonasal quadrants; Comparisons which show that pupil perimetry provided better results than Humphrey perimetry.

Blood pressure (BP) and intraocular pressure (IOP) show seasonal variations. In this prospective study, we measured the IOP, BP, SCT and choroidal blood flow velocity of the right eye of 50 young, healthy volunteers (17 men and 33 women; mean age, 20.7 ± 4.5 years). In healthy participants, systolic BP (SBP), diastolic BP (DBP), MBP, OPP and MBR were significantly higher in winter than in summer. [Extracted from the article]

The article presents the case study of a 52 year old man who complained of metamorphopsia in his left eye. He was referred to a nearby clinic and a macular hole in the left eye was diagnosed. The article further discusses the use of optical coherence tomography scanner (OCT) for the closure of macular holes.

Purpose: To investigate the association between long-term regular exercise (exercise frequency and exercise time) and 5-year changes in intraocular pressure in a general Japanese population. Methods: This population-based, cohort study was conducted in 2007. A total of 3119 Japanese community dwellers aged ≥ 40 years underwent eye examinations including intraocular pressure measurement with a noncontact tonometer. Of these, 1871 subjects (801 men and 1070 women) who underwent intraocular pressure measurement in 2012 participated. We assessed the associations of exercise frequency and exercise time with intraocular pressure using a linear regression model, adjusted for age and possible risk factors that can affect intraocular pressure. Results: The mean 5-year intraocular pressure change ± standard deviation was − 0.84 ± 1.9 mmHg. After adjustment for age, sex, systolic blood pressure, diabetes, total cholesterol, high-density lipoprotein cholesterol, body mass index, waist circumference, smoking habit, alcohol intake, work intensity levels, and intraocular pressure at baseline, we observed that increased exercise frequency (times/week) and increased exercise time (min/week) were both significantly associated with reduced intraocular pressure (p < 0.05 each). In the subgroup analyses based on the presence/absence of possible confounding risk factors, there was no evidence of heterogeneity among all subgroups (p for heterogeneity > 0.2). Conclusions: Increased exercise frequency levels and increased exercise time are both independently associated with reduced intraocular pressure levels after adjustment for confounding factors. [ABSTRACT FROM AUTHOR]

To elucidate the clinical and epidemiologic characteristics of optic neuritis in Japan. Multicenter cross-sectional, observational cohort study. A total of 531 cases of unilateral or bilateral noninfectious optic neuritis identified in 33 institutions nationwide in Japan. Serum samples from patients with optic neuritis were tested for anti–aquaporin-4 antibodies (AQP4-Abs) and anti–myelin oligodendrocyte glycoprotein antibodies (MOG-Abs) using a cell-based assay and were correlated with the clinical findings. Antibody positivity, clinical and radiologic characteristics, and visual outcome. Among 531 cases of optic neuritis, 12% were AQP4-Ab positive, 10% were MOG-Ab positive, 77% were negative for both antibodies (double-negative), and 1 case was positive for both antibodies. Pretreatment visual acuity (VA) worsened to more than a median 1.0 logarithm of the minimum angle of resolution (logMAR) in all groups. After steroid pulse therapy (combined with plasmapheresis in 32% of patients in AQP4-Ab–positive group), median VA improved to 0.4 logMAR in the AQP4-Ab–positive group, 0 logMAR in the MOG-Ab–positive group, and 0.1 logMAR in the double-negative group. The AQP4-Ab–positive group showed a high proportion of females, exhibited diverse visual field abnormalities, and demonstrated concurrent spinal cord lesions on magnetic resonance imaging (MRI) in 22% of the patients. In the MOG-Ab–positive group, although posttreatment visual outcome was good, the rates of optic disc swelling and pain with eye movement were significantly higher than those in the AQP4-Ab–positive and double-negative groups. However, most cases showed isolated optic neuritis lesions on MRI. In the double-negative group, 4% of the patients had multiple sclerosis. Multivariate logistic regression analysis of all participants identified age and presence of antibodies (MOG-Ab and AQP4-Ab) as significant factors affecting visual outcome. The present large-scale cohort study revealed the clinicoepidemiologic features of noninfectious optic neuritis in Japan. Anti–aquaporin-4 antibody–positive optic neuritis has poor visual outcome. In contrast, MOG-Ab positive cases manifested severe clinical findings of optic neuritis before treatment, but few showed concurrent lesions in sites other than the optic nerve and generally showed good treatment response with favorable visual outcome. These findings indicate that autoantibody measurement is useful for prompt diagnosis and proper management of optic neuritis that tends to become refractory. [ABSTRACT FROM AUTHOR]

Purpose To investigate optic disc margin anatomic features in myopic eyes with open-angle glaucoma (OAG) using spectral-domain (SD) OCT. Design Cross-sectional study. Participants Two hundred four eyes of 102 participants with OAG and 106 eyes of 53 participants without glaucoma with axial length of 24 mm or more. Methods Radial SD OCT B-scans centered on the optic discs were acquired in each eye, and the SD OCT data were colocalized with the optic disc stereophotographs. Optic disc margin anatomic features were evaluated as (1) SD OCT structure coinciding with the disc margin identified in the stereophotograph, (2) border tissue configuration, and (3) presence of Bruch's membrane overhang, and their frequency was computed in each clock-hour position. Further, paired eyes of myopic participants with OAG were divided into eyes with better or worse visual field defect (VFD), according to the mean deviation of the Humphrey visual field test, and associated factors were compared. Main Outcome Measures Spectral-domain OCT structures coinciding with the visible optic disc margin in stereophotographs. Results In myopic eyes with OAG, mean axial length was 25.96±1.07 mm and mean deviation was –8.87±7.78 dB. In approximately 90% of the participants, anterior scleral opening (ASO) coincided with the temporal disc margin and Bruch's membrane opening (BMO) with the nasal disc margin. Border tissue configuration was externally oblique in the temporal region and internally oblique in the nasal region of the optic disc. Bruch's membrane overhang was observed in a relatively small percentage of eyes. The same pattern of disc margin anatomic features was observed in the myopic eyes without glaucoma. The myopic optic disc was shaped by the temporal shifting of the BMO from the ASO, and the extent of shifting was expressed as the width of γ zone parapapillary atrophy (PPA). The greater γ zone PPA width was associated significantly with the worse VFD between paired eyes. Conclusions The myopic eyes with OAG exhibited characteristic optic disc margin anatomic features that was considered to be derived from myopic deformation of the eye. The greater γ zone PPA width may increase susceptibility to the glaucomatous stress. [ABSTRACT FROM AUTHOR]

Purpose: To estimate the prevalence and risk factors for polypoidal choroidal vasculopathy (PCV) in a general Japanese population.Methods: This population-based, cross-sectional study was conducted in 2007 with subjects from the Hisayama Study. Of the 3,648 residents in Hisayama, Japan, 2,663 who were ≥ 50 years old were enrolled in this study. The characteristics of PCV were determined by fundus examination or based on indocyanine green and fluorescein angiographic findings. We evaluated the contributions of the risk factors for PCV.Results: Among the 207 participants with age-related macular degeneration (AMD), 174 (6.5%) had early AMD, and 33 (1.2%) had late AMD, including 10 participants with PCV (0.4%). Male and smoking habit were significant risk factors for the development of PCV.Conclusions: The prevalence of PCV is higher among Japanese subjects than Caucasians in Western countries. Male gender and smoking habit were significant risk factors for PCV in a general Japanese population. [ABSTRACT FROM AUTHOR]

Purpose: The influence of myopia on glaucoma progression remains unknown, possibly because of the multifactorial nature of glaucoma and difficulty in assessing a solo contribution of myopia. The purpose of this study is to investigate the association of myopia with visual field (VF) progression in glaucoma using a paired-eye design to minimize the influence of confounding systemic factors that are diverse among individuals. Methods: This retrospective study evaluated 144 eyes of 72 subjects with open-angle glaucoma, with similar intra-ocular pressure between paired eyes, spherical equivalent (SE) ≤ -2 diopter (D), and axial length ≥ 24 mm. Paired eyes with faster and slower VF progression were grouped separately, according to the global VF progression rate assessed by automated pointwise linear regression analysis. The SE, axial length, tilt ratio and torsion angle of optic discs, Bruch’s membrane (BM) opening area, and gamma zone parapapillary atrophy (PPA) width were compared between the two groups. Factors associated with faster VF progression were determined by logistic regression analysis. Results: The mean follow-up duration was 8.9 ± 4.4 years. The mean value of SE and axial length were -6.31 ± 1.88 D and 26.05 ± 1.12 mm, respectively. The mean global visual field progression rate was -0.32 ± 0.38 dB/y. Tilt ratio, BM opening area, and gamma zone PPA width were significantly greater in the eyes with faster VF progression than those with slower progression. In multivariate analysis, these factors were significantly associated with faster VF progression (all P < 0.05), while SE and axial length were not associated with it. Conclusion: In myopic glaucoma subjects, tilt of the optic disc and temporal shifting and enlargement of the BM opening were associated with faster rate of VF progression between paired eyes. This suggests that myopia influences VF progression in glaucomatous eyes via optic disc deformations rather than via refractive error itself. [ABSTRACT FROM AUTHOR]

Purpose: To examine the association of myopia with the visual field (VF) defects in open-angle glaucoma (OAG) using paired eyes to eliminate the effect of unknown confounding factors that are diverse among individuals. Methods: One hundred eighteen eyes of 59 subjects with myopia (spherical equivalent [SE] ≥ -2 diopter [D] and axial length ≥ 24.0 mm) whose intra-ocular pressure between paired eyes was similar and the mean deviation (MD) of the Humphrey VF test differed by more than 6 dB were included. Refractive errors (SE, axial length) and parameters associated with the papillary and parapapillary myopic deformation (tilt ratio, torsion angle, and β-zone parapapillary atrophy [PPA] area without Bruch’s membrane) were measured in each eye. The paired eyes were divided into worse and better eyes according to the MD of the VF, and parameters were compared between them. Further, multiple linear regression analysis was performed to examine the correlation of the difference in various parameters with the MD difference between paired eyes. Results: The SE of all eyes was -6.39 ± 2.15 D (mean ± standard deviation) and axial length was 26.42 ± 1.07 mm. MD of the worse and better VF eyes were -13.56 ± 6.65 dB and -4.87 ± 5.32 dB, respectively. Eyes with worse VFs had significantly greater SE, axial length, tilt ratio, and PPA area without Bruch’s membrane than those with better VFs (all P < 0.05). In multiple linear regression analysis, the difference of the MD between paired eyes was significantly correlated with the difference in the tilt ratio and PPA area without Bruch’s membrane. Conclusion: The myopic papillary and parapapillary deformations, but not refractive error itself, were related to the worse VF in paired eyes with OAG. This suggests that myopia influences the severity of the glaucomatous VF defects via structural deformation. [ABSTRACT FROM AUTHOR]

Purpose: The carbonic anhydrase inhibitor dorzolamide can increase optic nerve blood flow. The aim of the study reported here was to investigate the effect of dorzolamide on isolated rabbit ciliary arteries that supply the optic nerve. Methods: Changes in ciliary artery isometric tension and intracellular Ca concentration ([Ca]) were recorded to elucidate the underlying pharmacologic mechanisms by which dorzolamide regulates blood flow to the optic nerve. Results: Dorzolamide induced concentration-dependent relaxation of rabbit ciliary arteries that had been precontracted by exposure to a high potassium (high-K) solution. Neither pretreatment with 10 µM KB-R 7943, an Na/Ca exchanger inhibitor, nor alkalinization of the high-K solution had an effect on the dorzolamide-induced relaxation. Pretreatment with 100 µM N-nitro- l-arginine methylester, a nitric oxide synthase inhibitor ( n = 10), 10 µM indomethacin, a prostacyclin inhibitor ( n = 9), or 0.1 µM iberiotoxin, an inhibitor of endothelium-derived hyperpolarizing factor ( n = 7), did not change the concentration-dependent relaxation induced by dorzolamide. Incubation with 3 mM dorzolamide in a Ca-free solution did not change the transient contractions of the rabbit ciliary arteries induced by 1 µM histamine ( n = 9). However, 3 mM dorzolamide significantly suppressed the increase in [Ca] induced by the reintroduction of Ca to a calcium-free extracellular medium ( P < 0.05). Furthermore, 3 mM dorzolamide significantly suppressed the [Ca] increase induced by the high-K solution ( P < 0.05). Conclusions: Taken together, our results reveal a novel role for dorzolamide in relaxing the ciliary arteries. Our data support the hypothesis that the vasodilatory action of dorzolamide is mediated by inhibition of Ca entry through voltage-dependent Ca channels. [ABSTRACT FROM AUTHOR]

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly population, and the prevalence of the disease increases exponentially with every decade after the age of 50 years. While VEGF inhibitors are promising drugs for treating patients with ocular neovascularization, there are limitations to their potential for improving vision in AMD patients. Thus, future therapies are required to have the potential to improve visual outcomes. This paper will summarize the future strategies and therapeutic targets that are aimed at enhancing the efficacy and duration of effect of antiangiogenic strategies. [ABSTRACT FROM AUTHOR]

Purpose: To clarify the mechanism of prostaglandin (PG) analogue-dependent relaxation in ciliary arteries from wild-type (WT) and prostanoid receptor-deficient mice.Methods: The intracellular-free calcium concentration ([Ca(2+)](i)) in isolated WT mouse ciliary arteries was measured by fluorescence photometry. Reduction of [Ca(2+)](i) leading to vascular relaxation by PG analogues latanoprost, isopropyl unoprostone, or tafluprost was compared to the maximum increase of [Ca(2+)](i) by 50 mM KCl. The cyclooxygenase inhibitor indomethacin and the NO synthase inhibitor N(G)-nitro-(L)-arginine methylester ((L)-NAME) were added to investigate the involvement of vascular endothelial factors. Moreover, PG analogue-dependent reduction of [Ca(2+)](i) was measured in ciliary artery strips from FP, EP1, EP2, and EP3 receptor-deficient mice.Results: The 3 PG analogues reduced K(+)-dependent increase in [Ca(2+)](i) in a concentration-dependent manner. Indomethacin (10 μM) had little effect. The reductions of [Ca(2+)](i) induced by 10 μM PG analogues were not significantly affected by the treatment with the NO synthase inhibitor (L)-NAME (10(-4) M). The effect of all 3 PG analogues in FP and EP3 receptor-deficient arteries was similar to the effect in WT arteries. Latanoprost significantly enhanced the reduction of [Ca(2+)](i) in ciliary arteries from prostanoid EP1 and EP2 receptor-deficient mice compared to WT mice. Tafluprost had a similar effect in arteries from EP2 receptor-deficient mice.Conclusions: PG analogues latanoprost, isopropyl unoprostone, and tafluprost reduced the K(+)-dependent increase in [Ca(2+)](i) in isolated mouse ciliary arteries. Endothelial-derived factors and FP and EP3 receptors were not involved in the responses. The increased effectiveness of latanoprost and tafluprost in reducing [Ca(2+)](i) in EP1 and EP2 receptor-deficient arteries suggests that the PG analogues may act, at least partially, through nonprostanoid receptor pathways. For glaucoma patients, PG analogues can be selected to reduce the intraocular pressure and increase the ocular blood flow. [ABSTRACT FROM AUTHOR]

Purpose: To clarify the mechanism of prostaglandin (PG) analogue-dependent relaxation in ciliary arteries from wild-type (WT) and prostanoid receptor-deficient mice. Methods: The intracellular-free calcium concentration ([Ca2+]i) in isolated WT mouse ciliary arteries was measured by fluorescence photometry. Reduction of [Ca2+]i leading to vascular relaxation by PG analogues latanoprost, isopropyl unoprostone, or tafluprost was compared to the maximum increase of [Ca2+]i by 50 mM KCl. The cyclooxygenase inhibitor indomethacin and the NO synthase inhibitor NG-nitro-L-arginine methylester (L-NAME) were added to investigate the involvement of vascular endothelial factors. Moreover, PG analogue-dependent reduction of [Ca2+]i was measured in ciliary artery strips from FP, EP1, EP2, and EP3 receptor-deficient mice. Results: The 3 PG analogues reduced K+-dependent increase in [Ca2+]i in a concentration-dependent manner. Indomethacin (10 μM) had little effect. The reductions of [Ca2+]i induced by 10 μM PG analogues were not significantly affected by the treatment with the NO synthase inhibitor L-NAME (10−4 M). The effect of all 3 PG analogues in FP and EP3 receptor-deficient arteries was similar to the effect in WT arteries. Latanoprost significantly enhanced the reduction of [Ca2+]i in ciliary arteries from prostanoid EP1 and EP2 receptor-deficient mice compared to WT mice. Tafluprost had a similar effect in arteries from EP2 receptor-deficient mice. Conclusions: PG analogues latanoprost, isopropyl unoprostone, and tafluprost reduced the K+-dependent increase in [Ca2+]i in isolated mouse ciliary arteries. Endothelial-derived factors and FP and EP3 receptors were not involved in the responses. The increased effectiveness of latanoprost and tafluprost in reducing [Ca2+]i in EP1 and EP2 receptor-deficient arteries suggests that the PG analogues may act, at least partially, through nonprostanoid receptor pathways. For glaucoma patients, PG analogues can be selected to reduce the intraocular pressure and increase the ocular blood flow. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the effects of prostaglandin F2α (PGF2α) analogues on the endothelin-1 (ET-1)-induced impairment of optic nerve head (ONH) blood flow and on ET-1-induced contraction in isolated ciliary artery segments. In male rabbits, one of four PGF2α analogues [0.0015% tafluprost, 0.0015% 15-hydroxyl tafluprost (15-OH tafluprost), 0.005% latanoprost, or 0.004% travoprost] was topically administered at various pretreatment times before intravitreal ET-1 injection. ONH blood flow was estimated by the laser speckle method, which expresses blood velocity as a quantitative index, the squared blur rate (SBR). SBR was measured just before (baseline value) and at 30, 60, and 120 min after ET-1 injection. SBR was significantly decreased from 4.47 ± 0.20 to 3.50 ± 0.10 (78.6 ± 2.4% of baseline) at 120 min after intravitreal ET-1 injection (5 pmol/eye). The ET-1-induced decrease was almost completely prevented by tafluprost and significantly inhibited by the other three analogues. The inhibitory effect lasted longest with tafluprost, as indicated by the effective pretreatment times (tafluprost: 90, 120, or 240 min; 15-OH tafluprost: 90, but not 120 or 240 min; latanoprost and travoprost: 120, but not 240 min). In vitro, the effects of PGF2α analogues on ET-1-induced contractions in male rabbit ciliary arteries were evaluated using an isometric tension recording system. Tafluprost, latanoprost, travoprost, and 15-OH tafluprost concentration-dependently relaxed the 10 nM ET-1-induced ciliary artery contraction. Improvement of the ocular circulation may be superior with tafluprost than with the other PGF2α analogues. The underlying mechanism may involve relaxation of ocular resistance vessels. [ABSTRACT FROM AUTHOR]

Abstract: Vascular peripheral resistance is increased during hypertension, and endothelium-derived hyperpolarizing factor (EDHF) is an important for regulating vasodilation in small arteries. Therefore we characterized the role of EDHF in regulating vascular resistance of ocular ciliary arteries from spontaneous hypertensive rats (SHR) and age-matched Wistar Kyoto rats (WKY). Isometric tension recordings were used in isolated ocular ciliary artery segments from SHR and WKY. Ocular ciliary arteries pre-contracted with 100 μM norepinephrine exhibited a concentration-dependent relaxation to acetylcholine, and the effect on SHR arteries was smaller than that on WKY arteries (P < 0.05). The EDHF-mediated component of this relaxation, determined in the presence of 100 μM l-NAME plus 10 μM indomethacin, was also smaller in SHR than in WKY arteries (P < 0.05). Apamin (1 μM), a blocker of small-conductance calcium-activated K+ (KCa) channels, had no effect on EDHF-mediated relaxation in either preparation. However, charybdotoxin (0.1 μM), which blocks intermediate- and large-conductance KCa channels, and iberiotoxin (0.1 μM), which blocks large-conductance KCa channels, almost completely suppressed EDHF-mediated relaxation in both preparations. The tension of ciliary arteries from both SHR and WKY was increased above baseline by 100 μM l-NAME plus 10 μM indomethacin. In these preparations, apamin had no effect on the tension in arteries from either SHR or WKY. However, both charybdotoxin and iberiotoxin further increased tension above that induced by l-NAME and indomethacin. The increase was smaller for SHR than WKY (P < 0.05). In summary, the ability of EDHF to relax ocular ciliary artery vascular tone in SHR is smaller than in WKY. The large-conductance calcium-activated K+ channel is utilized in EDHF-signaling pathway. [Copyright &y& Elsevier]

Abstract: Our objective was to determine if tafluprost, a newly synthesized antiglaucoma drug, can relax precontracted rabbit ciliary arteries, and if so, to elucidate the underlying mechanism. We used isometric tension recordings of smooth muscle contractions and fluorescence photometry to monitor the change of intracellular free calcium concentration ([Ca2+]i) in isolated rabbit ciliary artery segments. Tafluprost induced a concentration-dependent relaxation in rabbit ciliary arteries precontracted with a high-K solution. The amplitude of relaxation induced by tafluprost was unchanged by 100μM l-NAME, 10μM indomethacin, denudation of vascular endothelium, 30μM thapsigargin, or 100μM ouabain. In Ca2+-free solution, 30μM tafluprost did not decrease the amplitude of contraction induced by 1μM histamine or the amplitude of the [Ca2+]i increase induced by 10μM histamine. The mechanism of tafluprost-induced relaxation was different from diltiazem, a voltage-dependent Ca2+ channel blocker. However, in thapsigargin-pretreated preparations incubated in Ca2+-free solution, tafluprost attenuated the capacitative increase of [Ca2+]i upon Ca2+ reintroduction to the extracellular medium. Thus, we conclude that tafluprost relaxed isolated rabbit ciliary artery segments precontracted with a high-K solution. The relaxing mechanism was not dependent on endothelial-derived factors, and not affected by the intracellular Ca2+ cycles or the Ca2+ extrusion component of the extracellular Ca2+ cycles. Relaxation of rabbit ciliary artery smooth muscle by tafluprost may be due, at least in part, to inhibition of capacitative Ca2+ entry from the extracellular space. [Copyright &y& Elsevier]

Abstract: Topical application of levobunolol hydrochloride, a β-adrenergic antagonist used for treatment of glaucoma, is reported to increase ocular blood flow. We studied the mechanism of levobunolol-induced vasodilation in arterial smooth muscle. The effects of levobunolol or other agents on isolated, pre-contracted rabbit ciliary artery were investigated using an isometric tension recording method. The effects of the same agents on intracellular free calcium ([Ca2+]i) in cultured human aortic smooth muscle cells were also studied by fluorophotometry. Levobunolol relaxed ciliary artery rings that were pre-contracted with either high-K solution, 1μM histamine, 10μM phenylephrine, or 100nM endothelin-1. The relaxation induced by levobunolol was concentration-dependent over the range of 10μM to 0.3mM. Inhibition of endothelial nitric oxide synthase or denudation of the endothelium did not affect this relaxation. Histamine-induced contractions were inhibited by the histamine H1 antagonist pyrilamine. Radioligand binding experiments showed that levobunolol did not bind to the H1 receptor. Further, histamine induced transient contraction in Ca2+-free solution, and levobunolol inhibited this contraction by 74.6±11.0%. In cultured smooth muscle cells in the presence of extracellular Ca2+, levobunolol significantly inhibited the histamine-induced elevation of [Ca2+]i. However, it did not inhibit the increase of [Ca2+]i in histamine-stimulated cells incubated in Ca2+-free solution. These results indicate that levobunolol may relax rabbit ciliary artery by two different mechanisms. First, the relaxation could be due to the blockade of Ca2+ entry through non-voltage-dependent Ca2+ channels. Second, levobunolol may change the Ca2+ sensitivity of vascular smooth muscle cells. [Copyright &y& Elsevier]

Abstract: Despite the obvious importance of limbal stem cells in corneal homeostasis and tumorigenesis, little is known about their specific biological characteristics. The purpose of this study was to characterize limbal slow-cycling cells based on the expression of ABCG2 and major histocompatibility complex (MHC) class II and the cell size. Wistar rats were daily injected with 5-bromo-2-deoxyuridine (BrdU) at a dose of 5mg/100g for 2 weeks. After 4-week BrdU-free period, corneal tissues were excised, and immunofluorescence staining for ABCG2, BrdU, and MHC class II was performed by confocal microscopy. In another series, corneal tissues of normal rat were double immunostained for ABCG2, keratin 14, keratin 3, CD11c, and MHC class II. In addition, limbal, peripheral and central corneal epithelial sheets were isolated by Dispase II digestion and dissociated into single cell by trypsin digestion and cytospin preparations were double immunostained for ABCG2 and MHC class II. The cell size and nucleus-to-cytoplasm (N/C) ratio of limbal ABCG2+ cells were analyzed and compared with those of cells from other zones. BrdU label-retaining cells (LRCs) with expression of ABCG2 were found in the limbal epithelial basal layer, but not in other parts of the cornea. Approximately 20% of these cells were MHC class II positive. All MHC class II+ cells in the corneal epithelium were positive for CD11c, a marker for dendritic cells (DCs). Double labeling with ABCG2 and keratin 14 showed that nearly four-fifth of limbal ABCG2+ cells were positive for keratin 14 but negative for keratin 3, exhibiting an undifferentiated epithelial cell lineage. Cytospin sample analysis revealed the presence of a distinct population of smaller ABCG2+ cells with expression of MHC class II with a larger N/C ratio in the limbal epithelium. A new population of small slow-cycling cells with large N/C ratio has been found to express ABCG2 in the limbal epithelial basal layer. Some of these cells normally express MHC class II antigen. These findings may have important implications for our understanding of the characteristics of limbal slow-cycling cells. [Copyright &y& Elsevier]

Abstract: Impairment of the ocular circulation induced by diabetes mellitus has not been fully defined, but is thought to be related to hemodynamic changes in the ocular circulation. The purpose of the present study is to investigate the functional and morphological changes occurring in the ciliary artery wall of rabbits with alloxan-induced diabetes mellitus. A single intravenous bolus injection of alloxan (100mg/kg) was given to each of 26 10-week-old rabbits and 16 sham-injected control rabbits. Twenty weeks later, control rabbits and diabetic rabbits were sacrificed, and their ciliary arteries were mounted in a myograph system. The responses of these arteries to high K+ solution (K-Krebs solution), phenylephrine and carbachol were investigated using isometric tension recording. L-NAME (NG-nitro-l-arginine methyl ester; 100μM) and indomethacin (1μM) were also used to test the mechanism causing the carbachol induced relaxation. The arteries were also examined morphologically. The maximum tensions induced by K-Krebs solution in this tissue were not significantly different: 17.2±0.8mN (n =16) in the control rabbits and 17.6±0.8mN (n =23) in the diabetic rabbits (P =0.36). Phenylephrine caused dose-dependent contraction with EC50 values of 1.3±0.4μM (n =6) in the control and 5.1±2.3μM (n =6) in the diabetic rabbits, but there was no significant difference between the two (P =0.36). Carbachol induced dose-dependent relaxations in segments precontracted with K-Krebs solution. These relaxations were significantly reduced in the diabetic rabbits. The maximum relaxation induced by carbachol was 77.0±2.4% (10μM) and 66.4±2.5% (100μM) in the control and diabetic rabbits, respectively. These values were significantly different (P =0.0076). The IC50 value for carbachol was 396.3±58.4nM (n =16) in the control, and 443.6±141.1nM (n =23) in the diabetic rabbit (P =0.87). Application of a 100μM nitric oxide synthase inhibitor, L-NAME, significantly inhibited the amplitude of relaxations evoked by carbachol (P =0.0066). However, these relaxations were not inhibited by pretreatment with 1μM indomethacin (P =0.60). Histologically, the frequency of invaginations was less in the diabetic arterioles with a flattening of the lamina in the diabetic rabbits than in the controls. The cytoplasm of endothelial cells contained large vacuoles, indicating weak adhesion to the lamina. Some endothelial cells even showed vacuolar degeneration due to breakdown of the cell membranes. However, the smooth muscle cells were well preserved in the diabetic rabbit. These results suggest that the mechanism of impairment of ocular circulation induced by diabetes mellitus is mainly the reduction of NO synthase due to endothelial cell dysfunction. Furthermore, the characteristics of rabbits with alloxan-induced diabetes mellitus probably make them a useful model for investigating ocular complications induced by diabetic mellitus. [Copyright &y& Elsevier]

We have investigated functional and morphological changes occurring in the wall of the hypercholesterolemic rabbit ciliary artery. A mutant rabbit with hypercholesterolemia and atherosclerosis was created by serial breeding. Ciliary arteries from hypercholesterolemic, age-matched control and young control rabbits'' eyes were mounted in a myograph system. The effects of phenylephrine (PE), carbachol and electrical field stimulation on this artery were investigated using isometric tension recording methods. The arteries were also examined morphologically. PE caused dose-dependent contraction in young control, age-matched control and hypercholesterolemic rabbits. The EC50 values were 1·0 μm (0·2–2·1, n=6), 1·4 μm (0·4–2·4, n=6) and 4·7 μm (1·8–7·7, n=8) in the young, age-matched controls and in the Kurosawa and Kusanagi-hypercholesterolemic (KHC) rabbits, respectively. The EC50 values of the KHC rabbit were significantly different from those of control.Electrical field stimulation evoked contraction only in the control rabbits. On the other hand, electrical field stimulation evoked relaxation when the ciliary artery was pre-contracted by 10 μm histamine in each type of rabbit equally. Carbachol also induced approximately equal dose-dependent relaxation after pre-contraction. The morphological findings of KHC rabbit ciliary artery revealed irregular contours on the internal elastic lamina and deformation of the shape of the medial smooth muscle cells with irregularity in size and widening of the intercellular spaces. However, the endothelial cells were well preserved. Compared with the ciliary artery, typical atherosclerotic changes existed in the intima, not the media, in the KHC rabbit aorta. In the hypercholesterolemic rabbit ciliary artery, the vasoconstricting function was reduced but vasodilatation was well preserved. Morphological findings supported this. The pharmacological vascular reactivity in the hypercholesterolemic rabbit ciliary artery is quite different from that of the large arteries. [Copyright &y& Elsevier]

Purpose. To characterize in vivo changes of adenylate cyclase activity in rabbit ciliary processes during the circadian cycle. Methods. After removal of vitreous, lens, retina and choroid from freshly enucleated rabbit eyes, the anterior segment and attached sclera was chilled in cold buffer containing the nonselective phosphodiesterase (PDE) inhibitor, 3-isobutyl-1-methylxanthine (IBMX). Then ciliary processes were excised and homogenized in ice cold trichloro-acetic acid (TCA) 2.5 min after IBMX treatment. Increased cyclic AMP in response to PDE inhibition was measured in ciliary processes at six times during the circadian cycle, after preganglionic section of the cervical sympathetic trunk (decentralization, DX), and after topical instillation of hydroxyamphetamine, timolol, brimonidine, rauwolscine or a soluble derivative of forskolin. Results. The increase of rabbit ciliary process cyclic AMP levels in response to PDE inhibition with IBMX was enhanced at night. Much of the enhanced nocturnal increase persisted in constant dark and was blunted by DX. Topical instillation of hydroxyamphetamine enhanced the increase during the day; whereas, timolol, a β-adrenergic antagonist, or brimonidine, an α[sub 2]-adrenergic agonist, blunted the IBMX induced increase. Neither instillation of rauwolscine, an α[sub 2]adrenergic antagonist, nor the soluble forskolin derivative enhanced the increase of cyclic AMP after IBMX. Conclusions. The technique reported here can be used to estimate ciliary process adenylate cyclase activity in vivo. There is a circadian rhythm of adenylate cyclase activity in rabbit ciliary processes that is driven in part by ocular sympathetic input and stimulation of β-adrenergic receptors. [ABSTRACT FROM AUTHOR]