Cost-effectiveness of behavioural counselling intervention compared with non-intervention for adult patients with metabolic syndrome to prevent cardiovascular diseases and type 2 diabetes in Japan: a microsimulation modelling study.

OBJECTIVES: Nationwide lifestyle intervention-specific health guidance (SHG) in Japan-employs counselling and education to change unhealthy behaviours that contribute to metabolic syndrome, especially obesity or abdominal obesity. We aimed to perform a model-based economic evaluation of SHG in a low participation rate setting. DESIGN: A hypothetical population, comprised 50 000 Japanese aged 40 years who met the criteria of the SHG, used a microsimulation using the Markov model to evaluate SHG's cost-effectiveness compared with non-SHG. This hypothetical population was simulated over a 35-year time horizon. SETTING: SHG is conducted annually by all Japanese insurers. OUTCOME MEASURES: Model parameters, such as costs and health outcomes (including quality-adjusted life-years, QALYs), were based on existing literature. Incremental cost-effectiveness ratios were estimated from the healthcare payer's perspective. Deterministic and probabilistic sensitivity analyses (PSA) were conducted to evaluate the uncertainty around the model input parameters. RESULTS: The simulation revealed that the total costs per person in the SHG group decreased by JPY53 014 (US$480) compared with that in the non-SHG group, and the QALYs increased by 0.044, wherein SHG was considered the dominant strategy despite the low participation rates. PSA indicated that the credibility intervals (2.5th-97.5th percentile) of the incremental costs and the incremental QALYs with the SHG group compared with the non-SHG group were -JPY687 376 to JPY85 197 (-US$6226 to US$772) and -0.009 to 0.350 QALYs, respectively. Each scenario analysis indicated that programmes for improving both blood pressure and blood glucose levels among other risk factors for metabolic syndrome are essential for improving cost-effectiveness. CONCLUSIONS: This study suggests that even small effects of counselling and education on behavioural modification may lead to the prevention of acute life-threatening events and chronic diseases, in addition to the reduction of medication resulting from metabolic syndrome, which results in cost savings.

Cost-Effectiveness of School Urinary Screening for Early Detection of IgA Nephropathy in Japan.

Importance: The evidence for and against screening for chronic kidney disease in youths who are asymptomatic is inconsistent worldwide. Japan has been conducting urinary screening in students for 50 years, allowing for a full economic evaluation that includes the clinical benefits of early detection and intervention for chronic kidney disease. Objectives: To evaluate the clinical effectiveness and cost-effectiveness of school urinary screening in Japan, with a focus on the benefits of the early detection and intervention for IgA nephropathy, and to explore key points in the model that are associated with the cost-effectiveness of the school urinary screening program. Design, Setting, and Participants: This economic evaluation with a cost-effectiveness analysis used a computer-simulated Markov model from the health care payer's perspective among a hypothetical cohort of 1 000 000 youths aged 6 years in first grade in Japanese elementary schools, followed up through junior and high school. The time horizon was lifetime. Costs and clinical outcomes were discounted at a rate of 2% per year. Costs were calculated in Japanese yen and 2020 US dollars (¥107 = US $1). Interventions: School urinary screening for IgA nephropathy was compared with no screening. Main Outcomes and Measures: Outcomes were costs and quality-adjusted life-years (QALYs). Cost-effectiveness was determined by evaluating whether the incremental cost-effectiveness ratio (ICER) per QALY gained remained less than ¥7 500 000 (US $70 093). Results: In the base case analysis, the ICER was ¥4 186 642 (US $39 127)/QALY, which was less than the threshold. There were 60.3 patients/1 000 000 patients in the no-screening strategy and 31.7 patients/1 000 000 patients in the screening strategy with an end-stage kidney disease. Cost-effectiveness improved as the number of screenings decreased (screening frequency <3 times: incremental cost, -¥75 [US $0.7]; incremental QALY, 0.00025; ICER, dominant), but the number of patients with end-stage kidney disease due to IgA nephropathy increased (40.9 patients/1 000 000 patients). Assuming the disutility due to false positives had a significant impact on the analysis; assuming a disutility of 0.01 or more, the population with no IgA nephropathy had an ICER greater than the threshold (¥8 304 093 [US $77 608]/QALY). Conclusions and Relevance: This study found that Japanese school urinary screening was cost-effective, suggesting that it may be worthy of resource allocation. Key factors associated with cost-effectiveness were screening cost, the probability of incident detection outside of screening, and IgA nephropathy incidence, which may provide clues to decision-makers in other countries when evaluating the program in their own context.

Real-world effectiveness of screening programs for age-related macular degeneration: amended Japanese specific health checkups and augmented screening programs with OCT or AI.

PURPOSE: To investigate the effectiveness of screening and subsequent intervention for age-related macular degeneration (AMD) in Japan. STUDY DESIGN: Best-case-scenario analysis using a Markov model. METHODS: The clinical effectiveness and cost-effectiveness of screening for AMD were assessed by calculating the reduction proportion of blindness and the incremental cost-effectiveness ratio (ICER). The Markov model simulation began at screening at the age of 40 years and ended at screening at the age of 90 years. The first-eye and second-eye combined model assumed annual state-transition probabilities in the development and treatment of AMD. Data on prevalence, morbidity, transition probability, utility value, and treatment costs were obtained from previously published reports. Sensitivity analysis was performed to assess the influence of the parameters. RESULTS: In the base-case analysis, screening for AMD every 5 years, beginning at age 40 years and ending at age 74 years (reflecting the screening ages of the current Japanese legal "Specific Health Checkups") showed a decrease of 40.7% in the total number of blind patients. The screening program reduced the number of blind people more than did the additional AREDS/AREDS2 formula supplement intake. However, the ICER of screening versus no screening was ¥9,846,411/QALY, which was beyond what people were willing to pay (WTP) in Japan. Sensitivity analysis revealed that neither OCT nor AI improved the ICER, but the scenario in which the prevalence of smoking decreased by 30% improved the ICER (¥4,655,601/QALY) to the level under the WTP. CONCLUSIONS: Ophthalmologic screening for AMD is highly effective in reducing blindness but is not cost-effective, as demonstrated by a Markov model based on real-world evidence from Japan.

Tear protein analysis in presumed congenital alacrima.

OBJECTIVES: It is often hard to reach a definitive diagnosis of congenital alacrima because of the difficultly in proving the lack of lacrimal tissue. We report here the distinct tear protein profile in presumed congenital alacrima. PATIENTS AND METHODS: A 13-year-old girl with presumed congenital alacrima and 15 healthy volunteers aged 23-35 years were included in this study. Tears were collected using Schirmer strips, and tear protein analyses were performed. Tear samples were collected from the patient with alacrima before and after surgical punctal occlusion of both the upper and lower puncta, and tear protein extract was fractionated using HPLC. Lactoferrin and albumin concentrations in the tears were separately determined using ELISA. RESULTS: The chromatogram in the patient greatly differed from that in normal subjects with low concentrations of secretory IgA, lipocalin-1, and lysozyme. ELISA results indicated that the tear fluid in the patient contained a high concentration of albumin but a minimal concentration of lactoferrin. Punctal occlusion improved the ocular surface findings, but major lacrimal protein concentrations remained low and tear albumin concentrations further increased. CONCLUSION: The tear protein profile of a patient with presumed congenital alacrima greatly differed from that of normal subjects. Tear protein analysis may be useful in making a diagnosis of congenital alacrima and in assessing the efficacy and mechanism of punctal occlusion.

Determination of 5-fluorouracil and tegafur in tear fluid of patients treated with oral fluoropyrimidine anticancer agent, S-1.

PURPOSE: To establish a method for the measurement of 5-fluorouracil (5-FU), and tegafur (FT) in tear samples from patients treated with oral fluoropyrimidine anticancer agent S-1. STUDY DESIGN: Cross-sectional study. METHODS: High performance liquid chromatographic (HPLC) method reported for plasma samples was modified for tear samples. Simulated-tear solutions containing lactoferrin, lysozyme and standard solution containing 5-FU or FT were prepared for preliminary measurements. Tear samples from seven patients treated with S-1 were included. The tears were collected following S-1 administration using Schirmer's strips. RESULTS: 5-FU and FT concentrations of pure standard solution without extraction process were detected as original concentration. However, on extraction, FT samples in simulated-tear solution showed a peak for 5-FU but not for FT. FT was converted to 5-FU in the extraction process. Decomposition from FT to 5-FU was suppressed when 50 mg/mL bovine serum albumin was added during extraction. The mean concentrations of 5-FU and FT in tears during S-1 treatment were 0.17 ± 0.11 and 1.94 ± 0.71 µg/mL, respectively. CONCLUSION: A simple HPLC method to determine 5-FU and FT in tear samples was established.

The effect of rebamipide ophthalmic suspension on ocular surface mucins in soft contact lens wearers.

PURPOSE: To evaluate the changes in ocular surface mucins with 2%rebamipide ophthalmic suspension treatment in soft contact lens (SCL) wearers. Rebamipide suspension is a mucin secretagogue approved for the treatment of dry eye syndrome in Japan. In this study, the fluorescence intensity of wheat germ agglutinin conjugate of fluorescein (F-WGA) was used as a marker of membrane-associated mucins, and sialic acid concentration in tear fluids as a marker of secreted mucins. METHODS: Thirty-two eyes of 16 SCL wearers with discomfort were treated with rebamipide suspension at a dose of one drop in each eye four times daily for two weeks. The parameters of clinical efficacy were tear break-up time, fluorescein staining scores for the cornea and conjunctiva, and Schirmer test values. Fluorescence intensities in the central cornea were measured by fluorophotometry after the application of 5% F-WGA solution. Tears collected by Schirmer test strips were analyzed by high-performance liquid chromatography, and the concentrations of sialic acid, total protein, and the four major tear proteins, namely secretory IgA, lactoferrin, lipocalin-1, and lysozyme were measured. RESULTS: Significant increases in F-WGA fluorescence intensities (p < 0.005) were seen in the corneal surfaces. Sialic acid concentrations increased over time; however, the differences were not statistically significant. Except for a slight increase in kerato-conjunctival staining scores (p < 0.05) and secretory IgA (p < 0.05), no other significant differences were seen among clinical parameters or tear proteins. CONCLUSIONS: Topical application of rebamipide suspension significantly increased F-WGA intensity, a marker of membrane-associated mucins in SCL wearers.

Influence of Ophthalmic Solutions on Tear Components.

Tear fluids are a mixture of secretions derived from lacrimal glands, accessory lacrimal glands, conjunctiva, and meibomian glands. Compositional changes to tears occur in the normal state and during ocular surface disease, such as dry eye conditions. We have investigated compositional changes to tears after topical application of ophthalmic solutions, with regard to tear-specific proteins (secretory immunoglobulin A, lactoferrin, lipocalin-1, and lysozyme) and ocular surface mucin in normal and dry eye conditions using high-performance liquid chromatography. After application of saline solution (0.9% sodium chloride) in normal subjects, transient but significant decreases in all tear components were observed. The recovery of protein concentrations took up to 30 minutes and lasted longer when the saline solution was applied more frequently. When applying ophthalmic solutions, a balance between washout and dilutional effects should be considered in addition to the therapeutic effect. Investigation of the effect of diquafosol solution (3%) in normal subjects revealed a significant increase in sialic acid concentration, a marker of ocular mucin, at 5 minutes after application, whereas a significant decrease was observed with saline. This result indicates the accelerated secretion of mucin from ocular tissues induced by diquafosol. A clinical study to determine the efficacy of diquafosol in patients with dry eye revealed improvements in tear breakup time, keratoconjunctival staining scores, and Schirmer test score, accompanied by an increase in sialic acid concentration in tears. Investigating normal and dry eye conditions through tear analysis may clarify the pathophysiology of dry eye conditions and support the efficacy of treatments.

Diquafosol for Soft Contact Lens Dryness: Clinical Evaluation and Tear Analysis.

PURPOSE: To evaluate the efficacy of topical application of 3% diquafosol tetrasodium solution for the treatment of soft contact lens (SCL) wearers with dryness. In addition to clinical tests and subjective symptoms, we assessed the fluorescence intensity of wheat germ agglutinin conjugate of fluorescein (F-WGA) used as a marker of membrane-associated mucins and sialic acid concentration in tear fluids as a marker of secreted mucins. METHODS: Twelve SCL wearers with dryness symptoms were treated with diquafosol for 4 weeks. Clinical tests included the tear film break-up time (BUT), corneal and conjunctival fluorescein staining scores, and Schirmer values. Subjective symptoms were evaluated by the Dry Eye-Related Quality-of-Life Score (DEQS). Fluorescence intensities in the central cornea were measured by fluorophotometry at 5 minutes after a 5% F-WGA solution was applied to the eye. The tears collected by the Schirmer test strips were analyzed by high-performance liquid chromatography (HPLC), and the concentrations of sialic acid; total protein; and the four major tear proteins secretory IgA, lactoferrin, lipocalin-1, and lysozyme proteins were measured. RESULTS: Comparing the results before and after diquafosol treatment, BUT (p < 0.01), kerato-conjunctival staining score (p < 0.05), corneal staining score (p < 0.05), and DEQS score (p < 0.01) showed statistically significant improvements. The F-WGA fluorescence intensities (p < 0.0001) significantly increased after treatment, whereas the concentrations of sialic acid and tear proteins remained unchanged. CONCLUSIONS: Topical application of diquafosol solution to the SCL wearers with dryness improved biomarker of membrane-associated mucins, BUT, staining of cornea and conjunctiva, and subjective symptoms.

Fluorophotometric Analysis of the Ocular Surface Glycocalyx in Soft Contact Lens Wearers.

PURPOSE: Unstable tear film characterized by shorting of tear break-up time (BUT) is associated with discomfort and dryness in contact lens wearers. The glycocalyx is thought to be crucial in maintaining the wettability and lubrication of the ocular surface. We evaluated the ocular surface glycocalyx in soft contact lens (SCL) wearers using a fluorescein-labeled wheat germ agglutinin (F-WGA) as a marker to demonstrate the ocular surface glycoconjugates in vivo. METHODS: Twenty experienced SCL wearers and 20 healthy volunteers with no history of CL wearing (controls) were enrolled in the study. After applying a 5% F-WGA solution to the eyes of study individuals, fluorescent intensities in their respective central corneas were measured by fluorophotometry. The relationship between F-WGA intensity in the corneal surface and clinical parameters associated with contact lens wear were analyzed. RESULTS: F-WGA fluorescence intensity in the SCL group was 418.5 ± 103.3, which was significantly lower than that of the controls (825.0 ± 179.8; p < 0.0001, Mann-Whitney test). F-WGA fluorescence intensity was not correlated with Schirmer's test values or age, whereas a statistically significant correlation between F-WGA fluorescence intensity and tear film BUT was observed (r = 0.77, p < 0.0001). The decrease in F-WGA fluorescence intensity could be reversed by discontinuation of SCL use. CONCLUSION: Reduction and/or compositional alteration of ocular surface glycocalyx may be one of the causative factors of SCL-induced eye dryness.

Diquafosol sodium ophthalmic solution for the treatment of dry eye: clinical evaluation and biochemical analysis of tear composition.

PURPOSE: To evaluate the clinical efficacy of 3% diquafosol sodium ophthalmic solution for dry eye, and to analyze the concentration of tear proteins and mucin-like substances after the treatment. METHODS: Fifty eyes of 25 patients with dry eye syndrome were prospectively enrolled. The patients were treated with diquafosol solution at a dose of 1 drop in each eye 6 times daily for 4 weeks. The parameters of clinical efficacy were tear osmolarity, tear breakup time (BUT), fluorescein staining scores for the cornea and conjunctiva, Schirmer test values, and subjective symptoms evaluated using the ocular surface disease index (OSDI). Tears collected with Schirmer test strips were analyzed by high-performance liquid chromatography, and the concentrations of the total protein and the 4 major tear proteins, namely, secretory IgA, lactoferrin, lipocalin-1, lysozyme, and N-acetyl-neuraminic acid (Neu5Ac), were measured. Neu5Ac is a major sialic acid, a marker of secretory mucins. RESULTS: The BUT, keratoconjunctival staining scores, and Schirmer test values were improved with statistical significance after the treatment with diquafosol solution, while changes in the other parameters, including tear osmolarity, corneal staining scores, and OSDI scores were not significant. The Neu5Ac concentration was significantly increased, which was not accompanied by changes in tear proteins. CONCLUSIONS: Topical application of diquafosol significantly improved the clinical parameters of the BUT, keratoconjunctival staining scores, and Schirmer test values and was accompanied by increased sialic acid content in the tears of patients with dry eye.

The Clinical Effectiveness and Cost-Effectiveness of Screening for Age-Related Macular Degeneration in Japan: A Markov Modeling Study.

OBJECTIVE: To investigate the cost-effectiveness of screening and subsequent intervention for age-related macular degeneration (AMD) in Japan. METHODS: The clinical effectiveness and cost-effectiveness of screening and subsequent intervention for AMD were assessed using a Markov model. The Markov model simulation began at the age of 40 years and concluded at the age of 90 years. The first-eye and second-eye combined model assumed an annual state-transition probability, development of prodromal symptoms, choroidal neovascularization (CNV), and reduction in visual acuity. Anti-vascular-endothelial-growth-factor (anti-VEGF) intravitreal injection therapy and photodynamic therapy (PDT) were performed to treat CNV. Intake of supplements was recommended to patients who had prodromal symptoms and unilateral AMD. Data on prevalence, morbidity, transition probability, utility value of each AMD patient, and treatment costs were obtained from published clinical reports. RESULTS: In the base-case analysis, screening for AMD every 5 years, beginning at the age of 50 years, showed a decrease of 41% in the total number of blind patients. The screening program reduced the incidence of blindness more than did the additional intake of supplements. However, the incremental cost-effectiveness ratio (ICER) of screening versus no screening was 27,486,352 Japanese yen (JPY), or 259,942 US dollars (USD) per quality-adjusted life year (QALY). In the sensitivity analysis, prodromal symptom-related factors for AMD had great impacts on the cost-effectiveness of screening. The lowest ICER obtained from the best scenario was 4,913,717 JPY (46,470 USD) per QALY, which was approximately equal to the willingness to pay in Japan. CONCLUSIONS: Ophthalmologic screening for AMD in adults is highly effective in reducing the number of patients with blindness but not cost-effective as demonstrated by a Markov model based on clinical data from Japan.

Diquafosol Tetrasodium Increases the Concentration of Mucin-like Substances in Tears of Healthy Human Subjects.

PURPOSE: This study was undertaken to determine the effect of topical application of diquafosol tetrasodium on proteins and mucin-like substances from tears of clinically healthy subjects. METHODS: Tears were collected from both the eyes of 10 healthy volunteers. Diquafosol tetrasodium solution (3%) was applied once to the right eye and 0.9% sodium chloride solution (saline) once to the left eye. Tear samples were collected by Schirmer test strips before application and 5, 15, 30 and 60 min after application. Sialic acid, a marker of mucin-like substances, and major tear proteins including secretory IgA, lactoferrin, lipocalin-1, and lysozyme were measured by high performance liquid chromatography. RESULTS: Levels of total protein, sIgA and lysozyme were transiently decreased in both groups but returned to baseline levels within 15 min after application. The concentration of lactoferrin and lipocalin-1 did not change significantly in both groups. Sialic acid in tears was significantly decreased 5 min after saline application, but significantly increased 5 min after diquafosol application. No significant difference in sialic acid was seen after 15 min in both groups. CONCLUSIONS: Topical application of saline and diquafosol resulted in transient decrease of tear proteins possibly due to wash out or dilution effects. In contrast, diquafosol application significantly increased sialic acid, although the effect was transient. This suggests diquafosol stimulates the secretion of mucins from ocular tissues of healthy human subjects.

Cost-utility analysis of screening for diabetic retinopathy in Japan: a probabilistic Markov modeling study.

PURPOSE: To evaluate the cost-effectiveness for a screening interval longer than 1 year detecting diabetic retinopathy (DR) through the estimation of incremental costs per quality-adjusted life year (QALY) based on the best available clinical data in Japan. METHODS: A Markov model with a probabilistic cohort analysis was framed to calculate incremental costs per QALY gained by implementing a screening program detecting DR in Japan. A 1-year cycle length and population size of 50,000 with a 50-year time horizon (age 40-90 years) was used. Best available clinical data from publications and national surveillance data was used, and a model was designed including current diagnosis and management of DR with corresponding visual outcomes. One-way and probabilistic sensitivity analyses were performed considering uncertainties in the parameters. RESULTS: In the base-case analysis, the strategy with a screening program resulted in an incremental cost of 5,147 Japanese yen (¥; US$64.6) and incremental effectiveness of 0.0054 QALYs per person screened. The incremental cost-effectiveness ratio was ¥944,981 (US$11,857) per QALY. The simulation suggested that screening would result in a significant reduction in blindness in people aged 40 years or over (-16%). Sensitivity analyses suggested that in order to achieve both reductions in blindness and cost-effectiveness in Japan, the screening program should screen those aged 53-84 years, at intervals of 3 years or less. CONCLUSIONS: An eye screening program in Japan would be cost-effective in detecting DR and preventing blindness from DR, even allowing for the uncertainties in estimates of costs, utility, and current management of DR.

Assessment of vision-related quality of life among patients with cataracts and the outcomes of cataract surgery using a newly developed visual function questionnaire: the VFQ-J11.

OBJECTIVE: To investigate vision-related quality of life (VRQoL) and associated factors in patients with cataracts and the outcomes of cataract surgery using the newly developed VRQoL instrument: the visual function questionnaire, 11-item Japanese version (the VFQ-J11). METHODS: A total of 457 patients scheduled for cataract surgery at 12 clinical sites from November 2008 through February 2010 were included in the study. The patients completed the VFQ-J11 before and 3 months after surgery. The VFQ-J11 was used to investigate factors associated with VRQoL of the cataract patients, the outcome of cataract surgery, and the predictors of improved VRQoL due to cataract surgery. RESULTS: In a multiple regression model, the VFQ-J11 score was significantly associated with corrected distance visual acuity in the better-seeing eye (better eye VA), and improvement in the VFQ-J11 score after cataract surgery was associated not only with improvement in the better eye VA, but also with improvement in the worse eye VA. Compared to one-eye cataract surgery, both-eyes surgery had a greater impact on VFQ-J11 score improvement. CONCLUSIONS: The VFQ-J11 is a good measure of VRQoL in cataract patients. The present study indicates that by including the domains measured in the VFQ, the VFQ-J11 can provide valid data on VRQoL and be less of a burden for patients.

Cost-utility analysis of cataract surgery in Japan: a probabilistic Markov modeling study.

OBJECTIVE: To evaluate with the best available clinical data in Japan the cost-effectiveness of cataract surgery through the estimation of the incremental costs per quality-adjusted life years (QALYs) gained. METHODS: A Markov model with a probabilistic cohort analysis was constructed to calculate the incremental costs per QALY gained by cataract surgery in Japan. A 1-year cycle length and a 20-year horizon were applied. Best available evidence in Japan supplied the model with data on the course of cataract surgery. Uncertainty was explored using univariate and probabilistic sensitivity analysis. RESULTS: In base case analysis, cataract surgery was associated with incremental costs of Japanese yen (¥) 551,513 (US$ 6,920) and incremental effectiveness of 3.38 QALYs per one cataract patient. The incremental cost effectiveness ratio (ICER) was ¥ 163,331 (US$ 2,049) per QALY. In Monte Carlo simulation, the average patient with cataract surgery accrued 4.65 [95 % confidence interval (CI): 2.75-5.69] more QALYs than patients without surgery, giving an ICER of ¥ 118,460 (95 % CI: 73,516-207,926) (US$ 1,486) per QALY. CONCLUSIONS: Cataract surgery in Japan is highly cost-effective even when allowing for the uncertainty of the known variability that exists in estimates of the costs, utilities, and postoperative complication rate.

Evaluation of the frequency of ophthalmic solution application: washout effects of topical saline application on tear components.

PURPOSE: To determine and compare the effects of single and frequent topical applications of saline solution on tear protein concentration in clinically normal subjects. MATERIALS AND METHODS: Tears were collected from both eyes of 11 normal volunteers using Schirmer's strips. Saline solution (0.9% sodium chloride) was applied once in the right eye and five times with an interval of 1 min each in the left eye. Tears were collected before and 5, 15, 30 and 60 min after application of the solution. Total tear protein concentration in the samples was measured by the Bradford method and major tear protein concentration (secretory immunoglobulin A, lactoferrin, lipocalin-1, lysozyme and sialic acid) was measured using a high-performance liquid chromatography assay. RESULTS: A significant decrease was observed in the concentration of total tear protein, major tear proteins and sialic acid after topical application of saline solution. This decrease was attributed to the washout and dilution effect. A low protein concentration persisted longer with more frequent application of the solution. The concentration of secretory immunoglobulin A and sialic acid concentration recovered slowly compared with that of other proteins. CONCLUSIONS: Even a single application of saline solution resulted in significant changes in major tear protein and sialic acid concentration in the tears of normal subjects. Differences in the recovery of tear protein concentration may be related to the process of protein production and secretion. A balance between normal tear function and the therapeutic effects of ophthalmic solutions should be considered when deciding the frequency of application, particularly in patients with dry eye.

Involvement of P38MAPK in human corneal endothelial cell migration induced by TGF-ß(2).

Because human corneal endothelial cells do not proliferate once the endothelial monolayer is formed, corneal wound healing is thought to be mediated by cell enlargement or migration rather than proliferation. However, the cellular mechanisms involved in corneal wound healing have not been fully determined. Because transforming growth factor-ß(2) (TGF-ß(2)) isoform is present in high concentrations in normal human aqueous humor, it may play a role in human corneal endothelial cell wound healing. The purpose of this study was to determine the effect of TGF-ß(2) on the proliferation and migration of cultured human corneal endothelial cells (HCECs). To achieve this, we first examined the effect of TGF-ß(2) on the wound closure rate in an in vitro HCEC wound healing model. However, unexpectedly TGF-ß(2) had no effect on the wound closure rate in this model. Therefore, a real-time cell electronic sensing (RT-CES) system and the BrdU incorporation assay were used to determine the effect of TGF-ß(2) (0.1-10 ng/ml) on cultured HCEC proliferation during in vitro wound healing. The specificity of this effect was confirmed by adding the TGF-ß receptor I kinase inhibitor. TGF-ß(2) inhibited the proliferation of HCECs in a dose dependent way and was blocked by TGF-ß receptor I kinase inhibitor. Next, the Boyden chamber assay was used to determine how TGF-ß(2) (10 ng/ml) affect HCEC migration. Exposure to TGF-ß(2) increased cell migration, and a synergistic effect was observed when FGF-2 was added. To determine whether the mitogen-activated protein kinase (MAPK) signaling pathway is involved in the migration of HCECs, western blot analysis and Bio-Plex™ suspension array were used to detect phosphorylation of Erk1/2, p38, and JNK in HCECs stimulated by TGF-ß(2) and/or FGF-2. The effect of the p38 MAPK inhibitor, SB239063 (10 µM), on TGF-ß(2) and/or FGF-2-induced cellular migration was determined by the Boyden chamber assay. Both TGF-ß(2) and FGF-2-induced p38 phosphorylation, and a synergistic effect was observed with exposure to both growth factors. SB 239063 inhibited TGF-ß(2) and FGF-2-induced migration of HCECs. These results indicate that TGF-ß(2) reduces proliferation but stimulates migration of cultured HCECs. In addition, TGF-ß(2) and FGF-2 may have synergistic effects on the migration of HCECs mediated by p38 MAPK phosphorylation.

Role of insulin in regulation of Na+-/K+-dependent ATPase activity and pump function in corneal endothelial cells.

PURPOSE: The Na(+)-/K(+)-dependent ATPase (Na,K-ATPase) expressed in the basolateral membrane of corneal endothelial cells plays an important role in the pump function of the corneal endothelium. The role of insulin in the regulation of Na,K-ATPase activity and pump function in corneal endothelial cells was investigated. METHODS: Confluent monolayers of mouse corneal endothelial cells were exposed to insulin. ATPase activity was evaluated by spectrophotometric measurement of phosphate released from ATP with the use of ammonium molybdate; Na,K-ATPase activity was defined as the portion of total ATPase activity sensitive to ouabain. Pump function was measured with the use of a Ussing chamber; pump function attributable to Na,K-ATPase activity was defined as the portion of the total short-circuit current sensitive to ouabain. Western blot analysis and immunocytochemistry were performed to measure the expression of the Na,K-ATPase alpha(1)-subunit. RESULTS: Insulin increased the Na,K-ATPase activity and pump function of cultured corneal endothelial cells. These effects were blocked by protein kinase C (PKC) inhibitors and protein phosphatases 1 and 2A inhibitor. Western blot analysis indicated that insulin decreased the ratio of the inactive Na,K-ATPase alpha(1)-subunit. Immunocytochemistry indicated that insulin increased the cell surface expression of the Na,K-ATPase alpha(1)-subunit. CONCLUSIONS: These results suggest that insulin increases the Na,K-ATPase activity and pump function of cultured corneal endothelial cells. The effect of insulin is mediated by PKC and presumably results in the activation of PP1, 2A, or both, which are essential for activating Na,K-ATPase by alpha(1)-subunit dephosphorylation.