Toshihiko Matsuo

Trehalose protects corneal epithelial cells from death by drying

AIM This study was designed to examine whether trehalose could protect corneal epithelial cells in culture from death by desiccation in order to test trehalose as a potential new eye drop for dry eye syndrome. METHODS Human corneal epithelial cells in near confluent culture in wells of a 96 well multidish were preincubated for 15 minutes with 2, 20, 50, 100, or 200 mM trehalose or maltose in phosphate buffered saline (PBS), PBS alone, or three kinds of commercially available artificial tear substitutes (one with borate buffered saline and the other two containing either hydroxyethylcellulose or hyaluronan). The medium was aspirated completely and cells were left dry for 30 minutes at room temperature in room humidity. Live cells and dead cells were visualised by fluorescent dyes and counted for statistical analysis. RESULTS The percentage of dead corneal epithelial cells after desiccation was significantly lower in preincubation with 50, 100, and 200 mM trehalose, compared with preincubation with PBS alone (p<0.0001, Kruskal-Wallis test, and p<0.05, Tukey-Kramer test). Trehalose at the concentration of 20 mM or lower, maltose at any concentrations, and commercially available artificial tear substitutes did not protect corneal epithelial cells from death by desiccation. CONCLUSIONS Trehalose at 50, 100, and 200 mM protected corneal epithelial cells in culture from death by desiccation. Trehalose could be used as a potential new eye drop for dry eye syndrome.

The prevalence of strabismus and amblyopia in Japanese Elementary School Children

Background: The purpose of this study is to elucidate the prevalence of strabismus and amblyopia in a large population of Japanese elementary school children, from Grade 1 to Grade 6, ages ranging from 6 to 12 years. The School Health Law requires that all pupils in Grade 1 to Grade 6 be examined for vision and eye problems. Visual acuity testing is done by school teachers and eye disease screening by school ophthalmologists. Pupils with suspected ocular diseases are further examined by extramural ophthalmologists and the results reported back to the schools. The schools then summarize and send uncorrected visual acuity and ocular disease incidence, together with other health statistics, to the municipal education committees. The data are forwarded to the Prefecture Governments and finally submitted to the Education Ministry of the Central Government. Both the Prefecture Governments and the Education Ministry publicize the school health statistics on their websites. The prevalence of strabismus and amblyopia remains unknown from these data because both diagnoses are included under the heading, eye diseases. Methods: Questionnaires asking about the numbers of children with different types of strabismus and amblyopia were sent to all elementary schools in Okayama Prefecture and the results were summarized. Results: The number of children covered by the return of questionnaires was 86,531 (76.4%) of 113,254 total pupils in Grade 1 to Grade 6 in Okayama Prefecture in the year 2003. The total numbers of children with strabismus and amblyopia were 1,112 (1.28%) and 125 (0.14%), respectively. The numbers of children with any type of exotropia and any type of esotropia were 602 (0.69%) and 245 (0.28%), respectively. The major types of strabismus and amblyopia were intermittent exotropia in 109 children (0.12%), accommodative esotropia in 19 children (0.02%), anisometropic amblyopia in 23 children (0.03%), and ametropic amblyopia in 12 children (0.01%). The number of children with strabismus of unknown type was 245 (0.28%) while the number of children with amblyopia of unknown type was 81 (0.09%). Conclusions: The prevalence rates of strabismus and amblyopia in this population of Japanese elementary school children were lower than those reported in Western countries. The exotropia/esotropia ratio were increased in comparison with past studies in Japan. The school eye doctors need to be more diligent in identifying and diagnosing various types of strabismus and amblyopia in order to contribute to the school vision screening program already in place in Japan

Risk factors for diabetic choroidopathy in patients with diabetic retinopathy

AbstractPurpose. To identify risk factors for diabetic choroidopathy in patients with type 2 diabetes. Methods. Forty-five consecutive patients with diabetic retinopathy underwent simultaneous indocyanine green angiography (ICG) and fluorescein angiography using a double detector and confocal scanning laser ophthalmoscopy in both eyes. Choroidal vascular abnormalities were evaluated by comparing the angiographic findings derived from the two methods. We analyzed the association between the presence of abnormal choroidal lesions evident on ICG angiography and several risk factors. Results. Choroidal abnormalities evident on ICG angiography but not on fluorescein angiography included hypofluorescent spots in 72 eyes (80%) of 40 patients (89%), small hyperfluorescent spots in 61 eyes (68%) of 35 patients (78%), and large hyperfluorescent spots in 32 eyes (36%) of 21 patients (47%). The severity of diabetic retinopathy was significantly associated with the presence of hypofluorescent spots (P=0.002, Cochran–Armitage test) in both eyes and with the small hyperfluorescent spots in the right eyes (P=0.047, Cochran–Armitage test). Glycosylated hemoglobin levels were significantly associated with the large hyperfluorescent spots in the right eyes (P=0.003, Fishers exact probability test), and the treatment regimen was significantly associated with the small hyperfluorescent spots in the left eyes (P=0.048, chi-square test). Conclusion. These data suggest that risk factors influencing the prevalence of diabetic choroidopathy in patients with type 2 diabetes mellitus may include severity of diabetic retinopathy, degree of diabetic control and treatment regimen.

Trehalose eye drops in the treatment of dry eye syndrome

OBJECTIVE Trehalose can protect human corneal epithelial cells in culture from death from desiccation. This study was designed to test the efficacy and safety of trehalose eyedrops in the treatment of moderate to severe dry eye syndrome. DESIGN A randomized, double-masked, dose-ranging, fellow eye-controlled clinical trial. PARTICIPANTS Thirty-four patients with moderate to severe dry eye syndrome. METHODS The patients used either 100 or 200 mM trehalose dissolved in saline six times daily in one eye and control saline in the other eye for 4 weeks. MAIN OUTCOME MEASURES Symptoms and signs in both eyes were recorded separately at baseline, 2 weeks, and 4 weeks. RESULTS Fluorescein and rose bengal staining scores of the ocular surface improved at both 2 weeks and 4 weeks in the eyes with 100 and 200 mM trehalose, compared with eyes with control saline (P = 0.0030 to P < 0.0001, respectively, Mann-Whitney U test). Tear film breakup time became significantly longer at 2 weeks and 4 weeks with 100 mM trehalose (P = 0.0024 and P < 0.0001, respectively), but not with 200 mM trehalose. No adverse effect attributable to trehalose solution was noted. CONCLUSIONS Trehalose solution was an effective and safe eyedrop for the treatment of moderate to severe dry eye syndrome in this group of patients.

Choroidal abnormalities in Behçet disease observed by simultaneous indocyanine green and fluorescein angiography with scanning laser ophthalmoscopy

OBJECTIVE To examine choroidopathy in patients with Behçet disease. DESIGN Prospective clinical study. PARTICIPANTS Thirty-three patients (63 eyes) with Behçet disease. INTERVENTION Patients underwent simultaneous indocyanine green (ICG) and fluorescein angiography with a double detector of scanning laser ophthalmoscopy. MAIN OUTCOME MEASURES Angiographic findings recorded on videotapes were evaluated. The relation of angiographic findings with systemic activity and aqueous inflammation was also analyzed. RESULTS Fluorescein angiography showed leakage in varying degrees from retinal vessels in 30 patients (53 eyes, 84%). The ICG angiographic findings were choroidal vascular wall staining in 16 eyes (25%), hyperfluorescent spots in 42 eyes (66%) and hypofluorescent plaques in 22 eyes (35%), both of which were not evident with fluorescein, leakage from choroidal vessels in 3 eyes (5%), and irregular filling of choriocapillaris in 11 eyes (17%). These findings did not have a statistically significant correlation with the presence or absence of aqueous inflammation or oral aphthous ulcerations. CONCLUSIONS The patients with Behçet disease showed choroidal abnormalities, which could be revealed only by ICG angiography, but not with funduscopy or fluorescein angiography. Simultaneous ICG and fluorescein angiography would be useful for examining choroidal lesions in Behçet disease.

Bovine Trabecular Cells Produce TIMP-1 and MMP-2 in Response to Mechanical Stretching

Bovine trabecular cells in growth phase were exposed to cyclic mechanical stretching of the bottom of a culture dish at a cycle of 30 seconds for 72 hours. The stretched cells produced significantly larger amounts of metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-1 (TIMP-1) after 72 hours, compared with cells in nonstretched control. In contrast, TIMP-2 and MMP-9 levels were not influenced by mechanical stretching. Trabecular cells would modify extracellular matrix in response to such mechanical stimuli as bending of trabecular meshwork or aqueous flow by the production of TIMP-1 and MMP-2.

Localization of alpha-2 adrenergic receptors in the human eye

To elucidate sites of the action of alpha-2 adrenergic drugs, we localized binding sites for a potent alpha-2 adrenergic agonist, UK-14,304, in sections of the human cadaveric eye by an in vitro ligand-binding technique and autoradiography. Its specific binding sites were found in the iris epithelium and ciliary epithelium at a high level, and also in the ciliary muscle, retina, retinal pigment epithelium (and/or choroid). Binding of UK-14,304 to the ocular pigments was prevented by preincubating the eye sections with chloroquine, which reduced the non-specific binding to a low level.

Trehalose Versus Hyaluronan or Cellulose in Eyedrops for the Treatment of Dry Eye

PurposeTrehalose eyedrops were found by a previous study to be safe and effective compared with saline in the treatment of moderate-to-severe dry eye syndrome. The present study was designed to compare the efficacy of trehalose eyedrops with that of the commercially available eyedrops containing hyaluronan or cellulose now used in the treatment of moderate-to-severe dry eye syndrome.MethodsIn a randomized, double-masked, 4-week crossover, controlled clinical trial, 36 patients with moderate-to-severe dry eye syndrome were divided into two groups: the hyaluronan (Hyalein)-comparison group (18 patients) and the hydroxyethylcellulose (Mytear)-comparison group (18 patients). Each group used either trehalose or one of the commercially available medications contained in a masked eyedrop container for the first 4 weeks, and then for the second 4 weeks, switched to either trehalose or the commercial eyedrop not used for the first 4 weeks. Symptoms and signs in both eyes were recorded at the baseline, at 4 weeks, and at 8 weeks.ResultsAt 4 weeks after the treatment, fluorescein and rose bengal staining scores of the ocular surface as well as the tear film breakup time had improved significantly with trehalose eyedrops compared with the commercially available eyedrops containing either hyaluronan or hydroxyethylcellulose (P < 0.001, Wilcoxon signed ranks test). In addition, all the objective signs were significantly better in patients who finished with trehalose at the end of the 8-week trial compared with those who finished with either of the two commercially available drugs. A larger number of patients evaluated trehalose as a better treatment than the commercially available eyedrops.ConclusionsTrehalose solution was a better treatment for moderate-to-severe dry eye syndrome in comparison with two commercially available eyedrops containing hyaluronan or hydroxyethylcellulose.

Concordance of strabismic phenotypes in monozygotic versus multizygotic twins and other multiple births.

PURPOSE The concordance of strabismic phenotypes was examined in monozygotic versus multizygotic twins and other multiple births to study the role of genetic background in different types of commitant strabismus. METHODS Medical charts of 45 consecutive pairs of twins (16 monozygotic and 18 dizygotic twins, and 11 with unknown zygosity), 3 sets of triplets (one monozygotic and 2 trizygotic triplets), and one set of quadruzygotic quadruplets examined at 6 institutions between 1973 and 1999 were reviewed retrospectively. The concordance was defined as both or all members having either esotropia or exotropia in common. RESULTS The concordance of strabismic phenotypes was noted in 33 of 49 pairs or sets (67.3%): 14 of 17 monozygotic twins or triplets (82.4%), 10 of 21 multizygotic twins, triplets, or quadruplets (47.6%), and 9 of 11 twins with unknown zygosity (81.8%). The concordance rate was significantly higher in monozygosity than in multizygosity (P =.043, Fisher exact probability test). The predominant concordant phenotypes in monozygosity were accommodative esotropia and intermittent exotropia. CONCLUSION A high concordance rate of strabismic phenotypes, predominantly of accommodative esotropia and intermittent exotropia in monozygosity, suggests the genetic background for these types of strabismus.

Basal nitric oxide production is enhanced by hydraulic pressure in cultured human trabecular cells

BACKGROUND/AIMS Nitric oxide donors reduce intraocular pressure. Human trabecular cells in culture were examined for their nitric oxide production in response to hydraulic pressure. METHODS Human trabecular cells were cultured from trabeculum tissue fragments excised during trabeculectomy and exposed to hydraulic pressure change in a culture flask connected to a glass syringe. The pressure was exerted by automatic infusion of the piston of the syringe and monitored by a pressure gauge. The intracellular nitric oxide level was measured in real time with a nitric oxide binding fluorescent dye, diaminofluorescein-2. RESULTS Intracellular nitric oxide levels in cultured trabecular cells showed spontaneous fluctuation during 400 seconds of observation. Peak levels of intracellular nitric oxide were significantly higher at hydraulic pressure of 30, 40, and 50 mm Hg, compared with 0 and 25 mm Hg (p<0.0001, one way ANOVA, and p<0.05, Tukey–Kramer test). The fluctuation was completely abolished by the presence of N-methyl-l-arginine (L-NMMA), a nitric oxide synthase inhibitor. The cultured trabecular cells were shown by immunohistochemistry to express brain nitric oxide synthase (bNOS). CONCLUSION Higher levels of hydraulic pressure enhanced basal production of nitric oxide in human trabecular cells. Nitric oxide would be a physiological mediator in the regulation of intraocular pressure.