Andrea I. Zambrano

Longitudinal Study of Age-Related Cataract Using Dynamic Light Scattering: Loss of α-Crystallin Leads to Nuclear Cataract Development

PURPOSE To conduct a longitudinal study on age-related nuclear cataracts using dynamic light scattering (DLS) to determine if cataract progression is associated with loss of the unbound form of the lens molecular chaperone protein, α-crystallin. DESIGN Natural history and cohort study. PARTICIPANTS Patients 30 years of age or older of either gender seeking treatment at the Wilmer Eye Institute Cornea-Cataract Department. METHODS All patients underwent a comprehensive dilated eye examination every 6 months, including slit-lamp grading of their lenses using the Age-Related Eye Disease Study (AREDS) clinical lens grading system and obtaining an estimate of unbound α-crystallin level in the nucleus, the α-crystallin index (ACI), using the National Aeronautics and Space Administration-National Eye Institute DLS device. We used a random effects statistical model to examine the relationship of lens opacity changes over time with ACI changes. MAIN OUTCOME MEASURES α-Crystallin Index (ACI) and AREDS nuclear cataract grade. RESULTS Forty-five patients (66 eyes) 34 to 79 years of age with AREDS nuclear lens grades of 0 to 3.0 were followed up every 6 months for a mean of 19 months (range, 6-36 months). We found that lenses with the lowest baseline levels of ACI had the most rapid progression of cataracts, whereas lenses with higher ACI at baseline had no or slower cataract progression. Lenses that lost α-crystallin at the highest rates during the study also had faster progression of nuclear cataracts than lenses with a slower rate of ACI loss. Kaplan-Meier survival curves showed that lenses with the lowest initial ACI had the highest risk of undergoing cataract surgery. CONCLUSIONS This longitudinal study corroborates our previous cross-sectional study finding that higher levels of unbound α-crystallin as assessed by ACI are associated with lower risk of cataract formation and that loss of ACI over time is associated with cataract formation and progression. This study suggested that assessment of ACI with the DLS device could be used as a surrogate for lens opacity risk in clinical studies, and for assessing nuclear cataract events in studies where cataract development may be a side effect of a drug or device.

The World Health Organization Recommendations for Trachoma Surveillance, Experience in Nepal and Added Benefit of Testing for Antibodies to Chlamydia trachomatis pgp3 Protein: NESTS Study.

Background The World Health Organization (WHO) now requires a second surveillance survey for trachoma after an impact assessment has found follicular trachoma (TF) <5% to determine if re-emergence has occurred. Using new WHO guidelines, we undertook surveillance surveys, and determined the prevalence of infection and antibody positivity, in two districts in Nepal. Methods 20 clusters were randomly selected within each district, 15 were randomly selected for antibody testing. In each cluster, we randomly selected 50 children ages 1–9 years and 100 adults ≥15 years. TF and trachomatous trichiasis (TT) were evaluated. Conjunctival swabs to test for chlamydial infection using GenXpert platform were obtained, and dried blood spots were collected to test for antibodies to Chlamydia Trachomatis pgp3 using the Luminex platform. Findings 3 cases of TF were found in the two districts, and one case of infection. Pgp3 antibody positivity was 2·4% (95% confidence interval: 1·4%, 3·7%), and did not increase with age (P = 0.24). No clustering of antibody positivity within communities was found. TT prevalence was <1/1,000 population. Interpretation The surveillance surveys, as proposed by WHO, showed no evidence for re-emergence of trachoma in two districts of Nepal. The low level and no significant increase by age in seroprevalence of antibodies to C trachomatis pgp3 antigen deserve further investigation as a marker of interruption of transmission.

Trachomatous Scarring and Infection With Non–Chlamydia Trachomatis Bacteria in Women in Kongwa, Tanzania

Purpose To assess for an association between conjunctival infection with nonchlamydial bacterial species and the presence of trachomatous scarring (TS) in women in central Tanzania. Methods Cross-sectional data were collected from a random sample of women ages 18 and older in 47 trachoma-endemic communities in Kongwa, Tanzania. Each participant completed a survey, provided a conjunctival swab sample, and received an ocular exam to assess for TS. Biologic samples were cultured for bacterial growth and speciation. Contingency tables were used to assess the associations between TS and bacterial carriage. Results Complete data was provided by 3882 women (80.7% of invitees). Of all samples, 14% resulted in a positive bacterial isolate. There was no association between TS and nonchlamydial bacterial carriage, whether assessed by species, pathogenicity, or in aggregate. There was a significant association between increasing age and TS severity, but not between age and bacterial carriage. No Corynebacterium was found in the swabs. Conclusions This study found no association between TS and nonchlamydial ocular infections, although associations with Corynebacterium cannot be ruled out.

Exposure to an Indoor Cooking Fire and Risk of Trachoma in Children of Kongwa, Tanzania.

Background Elimination of blinding trachoma by 2020 can only be achieved if affected areas have effective control programs in place before the target date. Identifying risk factors for active disease that are amenable to intervention is important to successfully design such programs. Previous studies have linked sleeping by a cooking fire to trachoma in children, but not fully explored the mechanism and risks. We propose to determine the risk for active trachoma in children with exposure to cooking fires by severity of trachoma, adjusting for other known risk factors. Methods Complete census of 52 communities in Kongwa, Tanzania, was conducted to collect basic household characteristics and demographic information on each family member. Information on exposure to indoor cooking fires while the mother was cooking and while sleeping for each child was collected. 6656 randomly selected children ages 1-9yrs were invited to a survey where both eyelids were graded for follicular (TF) and intense trachoma (TI) using the WHO simplified grading scheme. Ocular swab were taken to assess the presence of Chlamydia trachomatis. Findings 5240 (79%) of the invited children participated in the study. Overall prevalence for trachoma was 6·1%. Odds for trachoma and increased severity were higher in children sleeping without ventilation and a cooking fire in their room (TF OR = 1·81, 1·00–3·27 and TI OR 4·06, 1·96–8·42). Children with TF or TI who were exposed were more likely to have infection than children with TF or TI who were not exposed. There was no increased risk with exposure to a cooking fire while the mother was cooking. Conclusions In addition to known risk factors for trachoma, sleeping by an indoor cooking fire in a room without ventilation was associated with active trachoma and appears to substantially increase the risk of intense inflammation.

Inhibition of Corneal Neovascularization by Subconjunctival Injection of Fc-Endostatin, a Novel Inhibitor of Angiogenesis.

We assessed the antiangiogenic effects of subconjunctival injection of Fc-endostatin (FcE) using a human vascular endothelial growth factor-induced rabbit corneal neovascularization model. Angiogenesis was induced in rabbit corneas through intrastromal implantations of VEGF polymer implanted 2 mm from the limbus. NZW rabbits were separated into groups receiving twice weekly subconjunctival injections of either saline; 25 mg/mL bevacizumab; 2 mg/mL FcE; or 20 mg/mL FcE. Corneas were digitally imaged at 5 time points. An angiogenesis index (AI) was calculated (vessel length (mm) × vessel number score) for each observation. All treatment groups showed a significant decrease in the vessel length and AI compared to saline on all observation days (P < 0.001). By day 15, FcE 2 inhibited angiogenesis significantly better than FcE 20 (P < 0.01). There was no significant difference between FcE 2 and BV, although the values trended towards significantly increased inhibition by BV. BV was a significantly better inhibitor than FcE 20 by day 8 (P < 0.01). FcE was safe and significantly inhibited new vessel growth in a rabbit corneal neovascularization model. Lower concentration FcE 2 exhibited better inhibition than FcE 20, consistent with previous FcE studies referencing a biphasic dose-response curve. Additional studies are necessary to further elucidate the efficacy and clinical potential of this novel angiogenesis inhibitor.

Surveillance surveys for reemergent trachoma in formerly endemic districts in Nepal from 2 to 10 years after mass drug administration cessation

Importance To verify districts for elimination of blinding trachoma, the World Health Organization requires a population-based surveillance survey for follicular trachoma (TF) and trachomatous trichiasis (TT) 2 years after mass drug administration (MDA) activities have ceased. However, it is unknown if 2 years provides enough time to discover reemergence. Objective To determine the prevalence of trachoma from surveys among 4 districts in Nepal (Dailekh, Dang, Surkhet, and Kanchanpur) that had surveillance intervals of 2, 4, 8, and 10 years, respectively, after cessation of MDA. Design, Setting, and Participants Cross-sectional surveys were carried out in 2015 and 2016. Data analyses were done from March to September 2016. Among 20 clusters randomly selected from each district, 15 were randomly selected for infection and antibody testing: TF and TT were assessed, conjunctival swabs were tested for chlamydial infection, and blood spots were collected on filter paper to test for antibodies to Chlamydia trachomatis pgp3 using a multiplex bead assay. The study setting was 4 districts previously endemic for trachoma in Nepal. Participants were randomly selected and included 50 children aged 1 to 9 years and 100 adolescents and adults 15 years and older from each of the 20 clusters; this investigation reports on the children. Main Outcomes and Measures Length of time since the last round of MDA and the prevalence of TF among children aged 1 to 9 years and the prevalence of TT among adolescents and adults 15 years and older. Results Of 3024 children surveyed in the clusters, 48.0% (n = 1452) were female. The mean (SD) age of the children was 5.4 (2.6) years. Eleven cases of TF were found, with a TF prevalence less than 1% in all 4 districts. Three cases of infection were found. Seropositivity for pgp3 antibody varied from 1.4% (95% CI, 0.7-2.6) in the district with a 10-year surveillance interval to 2.5% (95% CI, 1.3-4.5) in the district with a 4-year surveillance interval. Seropositivity increased slightly with age in only one district. The TT prevalence was less than 1 case per 1000 among the total population in all 4 districts after accounting for cases known to the health system and cases with no scarred conjunctiva. Conclusions and Relevance This study found no evidence of reemergence of trachoma up to 10 years after cessation of MDA in 4 districts in children in Nepal. The recommendation for a surveillance survey at 2 years, as proposed by the World Health Organization, is supported by these data. Determining if individuals with TT had scarring or are known to the health system was critical for meeting elimination criteria of blinding trachoma.

Measuring trachomatous inflammation-intense (TI) when prevalence is low provides data on infection with Chlamydia trachomatis

Purpose Clinical trachoma is the current measure of effectiveness of antibiotic and environmental improvements in trachoma endemic communities. Impact assessments measure only trachomatous inflammation-follicular (TF). Trachomatous inflammation-intense (TI) is not used for decisions on stopping mass drug administration (MDA) or achieving intervention goals. We tested the supposition that TI was not associated with Chlamydia trachomatis when disease prevalence is low. Methods In 35 communities undergoing MDA as part of a larger project, 110 children ages 1 to 9 years were randomly selected in each community for surveys at baseline, 6, and 12 months. Both eyelids were graded for TF and TI, and a swab for detection of C. trachomatis infection was taken. Results Overall TF prevalence was 5% at baseline. Cases of TI alone constituted 15% of trachoma; 37% of TI cases had infection. At 6 and 12 months, the proportion of trachoma cases that had TI only was 13% and 20%; infection rates were similar to the rates in cases with TF alone. Conclusions Despite low prevalence of trachoma, infection rates for TF alone and TI alone were similar at each time point. The exclusion of cases of TI alone when reporting trachoma prevalence discards additional information on infection. Trachomatous inflammation-intense could be considered as part of impact surveys.