A multi-center comparison of surgical techniques for corpus Callosotomy in pediatric drug-resistant epilepsy

OBJECTIVES

Corpus callosotomy (CC) is used to reduce seizures, primarily in patients with generalized drug-resistant epilepsy (DRE). The invasive nature of the procedure contributes to underutilization despite its potential superiority to other palliative procedures. The goal of this study was to use a multi-institutional epilepsy surgery database to characterize the use of CC across participating centers.

METHODS

Data were acquired from the Pediatric Epilepsy Research Consortium (PERC) Surgery Database, a prospective observational study collecting data on children 0-18 years referred for surgical evaluation of DRE across 22 U.S. pediatric epilepsy centers. Patient, epilepsy, and surgical characteristics were collected across multiple CC modalities. Outcomes and complications were recorded and analyzed statistically.

RESULTS

Eighty-three patients undergoing 85 CC procedures at 14 participating epilepsy centers met inclusion criteria. Mean age at seizure onset was 2.3 years (0-9.4); mean age for Phase I evaluation and surgical intervention were 9.45 (.1-20) and 10.46 (.2-20.6) years, respectively. Generalized seizure types were the most common (59%). Complete CC was performed in 88%. The majority of CC procedures (57%) were via open craniotomy, followed by laser interstitial thermal therapy (LiTT) (20%) and mini-craniotomy/endoscopic (mc/e) (22%). Mean operative times were significantly longer for LiTT, whereas mean estimated blood loss was greater in open cases. Complications occurred in 11 cases (13%) and differed significantly between surgical techniques (p < .001). There was no statistically significant difference in length of postoperative stay across approaches. Mean follow-up was 12.8 months (range 1-39). Favorable Engel outcomes were experienced by 37 (78.7%) of the patients who underwent craniotomy, 10 (58.8%) with LiTT, and 12 (63.2%) with mc/e; these differences were not statistically significant.

SIGNIFICANCE

CC is an effective surgical modality for children with DRE. Regardless of surgical modality, complication rates are acceptable and seizure outcomes generally favorable. Newer, less-invasive, surgical approaches may lead to increased adoption of this efficacious therapeutic option for pediatric DRE.

Extending the use of biologics to mucous membranes by attachment of a binding domain

Biologics are almost exclusively administered systemically, but localized delivery is preferable as it minimizes off-target exposure and allows more aggressive treatments. Topical application of biologics to epithelia is generally ineffective because most are covered with fluids and biologics are washed out too quickly to have significant therapeutic effects. Here we explore the idea that attaching a binding domain can serve as an "anchor" to extend the residency time of biologics on wet epithelia, allowing their effective use even with infrequent applications. We use topical application to the ocular surface as a challenging test since foreign substances are washed out especially efficiently by tear flow and blinking. Our results demonstrate that conjugation of antibodies to wheat germ agglutinin, which binds GlcNAc and sialic acid that are ubiquitously present in tissues, increases their half-life 350-fold upon application to the ocular surface in a mouse model of dry eye, a common and onerous disease in humans. Importantly, antibodies to IL-17A, IL-23, and IL-1β conjugated to the agglutinin reduces manifestations of dry eye, even when applied just once daily. In contrast, unconjugated antibodies are ineffective. Attaching an anchor to biologics is a simple means to overcome washout and to extend their therapeutic use.

A synthetic tear protein resolves dry eye through promoting corneal nerve regeneration

Corneal architecture is essential for vision and is greatly perturbed by the absence of tears due to the highly prevalent disorder dry eye. With no regenerative therapies available, pathological alterations of the ocular surface in response to dryness, including persistent epithelial defects and poor wound healing, result in life-long morbidity. Here, using a mouse model of aqueous-deficient dry eye, we reveal that topical application of the synthetic tear protein Lacripep reverses the pathological outcomes of dry eye through restoring the extensive network of corneal nerves that are essential for tear secretion, barrier function, epithelial homeostasis, and wound healing. Intriguingly, the restorative effects of Lacripep occur despite extensive immune cell infiltration, suggesting tissue reinnervation and regeneration can be achieved under chronic inflammatory conditions. In summary, our data highlight Lacripep as a first-in-class regenerative therapy for returning the cornea to a near homeostatic state in individuals who suffer from dry eye.

Currently, there are no regenerative treatments for ocular pathologies due to dry eye. Efraim et al. demonstrate the synthetic tear peptide Lacripep as a regenerative therapy capable of restoring the damaged, dysfunctional ocular surface to a near homeostatic state through promoting nerve regeneration in the presence of chronic inflammation.

Surgical evaluation in children <3 years of age with drug-resistant epilepsy: Patient characteristics, diagnostic utilization, and potential for treatment delays

OBJECTIVE

Drug-resistant epilepsy (DRE) occurs at higher rates in children <3 years old. Epilepsy surgery is effective, but rarely utilized in young children despite developmental benefits of early seizure freedom. The present study aims to identify unique patient characteristics and evaluation strategies in children <3 years old who undergo epilepsy surgery evaluation as a means to assess contributors and potential solutions to health care disparities in this group.

METHODS

The Pediatric Epilepsy Research Consortium Epilepsy Surgery Database, a multicentered, cross-sectional collaboration of 21 US pediatric epilepsy centers, collects prospective data on children <18 years of age referred for epilepsy surgery evaluation. We compared patient characteristics, diagnostic utilization, and surgical treatment between children <3 years old and those older undergoing initial presurgical evaluation. We evaluated patient characteristics leading to delayed referral (>1 year) after DRE diagnosis in the very young.

RESULTS

The cohort included 437 children, of whom 71 (16%) were <3 years of age at referral. Children evaluated before the age of 3 years more commonly had abnormal neurological examinations (p = .002) and daily seizures (p = .001). At least one ancillary test was used in 44% of evaluations. Fifty-nine percent were seizure-free following surgery (n = 34), with 35% undergoing limited focal resections. Children with delayed referrals more often had focal aware (p < .001) seizures and recommendation for palliative surgeries (p < .001).

SIGNIFICANCE

There are relatively few studies of epilepsy surgery in the very young. Surgery is effective, but may be disproportionally offered to those with severe presentations. Relatively low utilization of ancillary testing may contribute to reduced surgical therapy for those without evident lesions on magnetic resonance imaging. Despite this, a sizeable portion of patients have favorable outcome after focal epilepsy surgery resections.

Early-life epilepsy after acute symptomatic neonatal seizures: A prospective multicenter study

OBJECTIVE

We aimed to evaluate early-life epilepsy incidence, seizure types, severity, risk factors, and treatments among survivors of acute neonatal seizures.

METHODS

Neonates with acute symptomatic seizures born 7/2015-3/2018 were prospectively enrolled at nine Neonatal Seizure Registry sites. One-hour EEG was recorded at age three months. Post-neonatal epilepsy and functional development (Warner Initial Developmental Evaluation of Adaptive and Functional Skills - WIDEA-FS) were assessed. Cox regression was used to assess epilepsy-free survival.

RESULTS

Among 282 infants, 37 (13%) had post-neonatal epilepsy by 24-months [median age of onset 7-months (IQR 3-14)]. Among those with post-neonatal epilepsy, 13/37 (35%) had infantile spasms and 12/37 (32%) had drug-resistant epilepsy. Most children with post-neonatal epilepsy had abnormal neurodevelopment at 24-months (WIDEA-FS >2SD below normal population mean for 81% of children with epilepsy vs 27% without epilepsy, RR 7.9, 95% CI 3.6-17.3). Infants with severely abnormal neonatal EEG background patterns were more likely to develop epilepsy than those with mild/moderate abnormalities (HR 3.7, 95% CI 1.9-5.9). Neonatal EEG with ≥3 days of seizures also predicted hazard of epilepsy (HR 2.9, 95% CI 1.4-5.9). In an adjusted model, days of neonatal EEG-confirmed seizures (HR 1.4 per day, 95% CI 1.2-1.6) and abnormal discharge examination (HR 3.9, 95% CI 1.9-7.8) were independently associated with time to epilepsy onset. Abnormal (vs. normal) three-month EEG was not associated with epilepsy.

SIGNIFICANCE

In this multicenter study, only 13% of infants with acute symptomatic neonatal seizures developed post-neonatal epilepsy by age 24-months. However, there was a high risk of severe neurodevelopmental impairment and drug-resistant seizures among children with post-neonatal epilepsy. Days of EEG-confirmed neonatal seizures was a potentially modifiable epilepsy risk factor. An EEG at three months was not clinically useful for predicting epilepsy. These practice changing findings have implications for family counseling, clinical follow-up planning, and future research to prevent post-neonatal epilepsy.

Safety of Early Discontinuation of Antiseizure Medication After Acute Symptomatic Neonatal Seizures

Question

Is discontinuation of antiseizure medication (ASM) after resolution of acute symptomatic neonatal seizures and prior to discharge from the hospital associated with functional neurodevelopment or epilepsy at 24 months?

Findings

In this comparative effectiveness study of 303 children with neonatal seizures from 9 centers, 64% had ASM maintained at hospital discharge. No difference was found between ASM maintenance and discontinuation groups in functional neurodevelopment or epilepsy; 13% of children developed epilepsy, including more than one-third with infantile spasms.

Meaning

These results support discontinuing ASMs for most neonates with acute symptomatic seizures prior to discharge from the hospital, an approach that may represent an evidence-based change in practice for many clinicians.

Importance

Antiseizure medication (ASM) treatment duration for acute symptomatic neonatal seizures is variable. A randomized clinical trial of phenobarbital compared with placebo after resolution of acute symptomatic seizures closed early owing to low enrollment.

Objective

To assess whether ASM discontinuation after resolution of acute symptomatic neonatal seizures and before hospital discharge is associated with functional neurodevelopment or risk of epilepsy at age 24 months.

Design, Setting, and Participants

This comparative effectiveness study included 303 neonates with acute symptomatic seizures (282 with follow-up data and 270 with the primary outcome measure) from 9 US Neonatal Seizure Registry centers, born from July 2015 to March 2018. The centers all had level IV neonatal intensive care units and comprehensive pediatric epilepsy programs. Data were analyzed from June 2020 to February 2021.

Exposures

The primary exposure was duration of ASM treatment dichotomized as ASM discontinued vs ASM maintained at the time of discharge from the neonatal seizure admission. To enhance causal association, each outcome risk was adjusted for propensity to receive ASM at discharge. Propensity for ASM maintenance was defined by a logistic regression model including seizure cause, gestational age, therapeutic hypothermia, worst electroencephalogram background, days of electroencephalogram seizures, and discharge examination (all P ≤ .10 in a joint model except cause, which was included for face validity).

Main Outcomes and Measures

Functional neurodevelopment was assessed by the Warner Initial Developmental Evaluation of Adaptive and Functional Skills (WIDEA-FS) at 24 months powered for propensity-adjusted noninferiority of early ASM discontinuation. Postneonatal epilepsy, a prespecified secondary outcome, was defined per International League Against Epilepsy criteria, determined by parent interview, and corroborated by medical records.

Results

Most neonates (194 of 303 [64%]) had ASM maintained at the time of hospital discharge. Among 270 children evaluated at 24 months (mean [SD], 23.8 [0.7] months; 147 [54%] were male), the WIDEA-FS score was similar for the infants whose ASMs were discontinued (101 of 270 [37%]) compared with the infants with ASMs maintained (169 of 270 [63%]) at discharge (median score, 165 [interquartile range, 150-175] vs 161 [interquartile range, 129-174]; P = .09). The propensity-adjusted average difference was 4 points (90% CI, −3 to 11 points), which met the a priori noninferiority limit of −12 points. The epilepsy risk was similar (11% vs 14%; P = .49), with a propensity-adjusted odds ratio of 1.5 (95% CI, 0.7-3.4; P = .32).

Conclusions and Relevance

In this comparative effectiveness study, no difference was found in functional neurodevelopment or epilepsy at age 24 months among children whose ASM was discontinued vs maintained at hospital discharge after resolution of acute symptomatic neonatal seizures. These results support discontinuation of ASM prior to hospital discharge for most infants with acute symptomatic neonatal seizures.

Treatment Practices and Outcomes in Continuous Spike and Wave during Slow Wave Sleep: A Multicenter Collaboration

OBJECTIVES

To determine how continuous spike and wave during slow wave sleep (CSWS) is currently managed and to compare the effectiveness of current treatment strategies using a database from 11 pediatric epilepsy centers in the US.

STUDY DESIGN

This retrospective study gathered information on baseline clinical characteristics, CSWS etiology, and treatment(s) in consecutive patients seen between 2014 and 2016 at 11 epilepsy referral centers. Treatments were categorized as benzodiazepines, steroids, other antiseizure medications (ASMs), or other therapies. Two measures of treatment response (clinical improvement as noted by the treating physician; and electroencephalography improvement) were compared across therapies, controlling for baseline variables.

RESULTS

Eighty-one children underwent 153 treatment trials during the study period (68 trials of benzodiazepines, 25 of steroids, 45 of ASMs, 14 of other therapies). Children most frequently received benzodiazepines (62%) or ASMs (27%) as first line therapy. Treatment choice did not differ based on baseline clinical variables, nor did these variables correlate with outcome. After adjusting for baseline variables, children had a greater odds of clinical improvement with benzodiazepines (OR 3.32, 95%CI 1.57-7.04, P = .002) or steroids (OR 4.04, 95%CI 1.41-11.59, P = .01) than with ASMs and a greater odds of electroencephalography improvement after steroids (OR 3.36, 95% CI 1.09-10.33, P = .03) than after ASMs.

CONCLUSIONS

Benzodiazepines and ASMs are the most frequent initial therapy prescribed for CSWS in the US. Our data suggests that ASMs are inferior to benzodiazepines and steroids and support earlier use of these therapies. Multicenter prospective studies that rigorously assess treatment protocols and outcomes are needed.

Risk for infantile spasms after acute symptomatic neonatal seizures

OBJECTIVE

Infantile spasms (IS) is a severe epilepsy in early childhood. Early treatment of IS provides the best chance of seizure remission and favorable developmental outcome. We aimed to develop a prediction rule to accurately predict which neonates with acute symptomatic seizures will develop IS.

METHODS

We used data from the Neonatal Seizure Registry, a prospective, multicenter cohort of infants with acute symptomatic neonatal seizures born from July 2015 to March 2018. Neonates with acute symptomatic seizures who received clinical electroencephalography (EEG) and magnetic resonance imaging (MRI) and were younger than 2 years of age at the time of enrollment were included. We evaluated the association of neonatal EEG, MRI, and clinical factors with subsequent IS using bivariate analysis and best subsets logistic regression. We selected a final model through a consensus process that balanced statistical significance with clinical relevance.

RESULTS

IS developed in 12 of 204 infants (6%). Multiple potential predictors were associated with IS, including Apgar scores, EEG features, seizure characteristics, MRI abnormalities, and clinical status at hospital discharge. The final model included three risk factors: (a) severely abnormal EEG or ≥3 days with seizures recorded on EEG, (b) deep gray or brainstem injury on MRI, and (c) abnormal tone on discharge exam. The stratified risk of IS was the following: no factors 0% (0/82, 95% confidence interval [CI] 0%-4%), one or two factors 4% (4/108, 95% CI 1%-9%), and all three factors 57% (8/14, 95% CI 29%-83%).

SIGNIFICANCE

IS risk after acute symptomatic neonatal seizures can be stratified using commonly available clinical data. No child without risk factors, vs >50% of those with all three factors, developed IS. This risk prediction rule may be valuable for clinical counseling as well as for selecting participants for clinical trials to prevent post-neonatal epilepsy. This tailored approach may lead to earlier diagnosis and treatment and improve outcomes for a devastating early life epilepsy.

Development of a Quantitative Immunoassay for Tear Lacritin Proteoforms

Purpose

Lacritin is a tear glycoprotein with pro-tearing and pro-ocular surface homeostasis activities that is selectively deficient in most dry eye tears. Proteoforms include an active monomer, inactive polymers, and a splice variant termed lacritin-c. Quantitation of the different proteoforms of tear lacritin may provide a diagnostic tool for ocular diseases. Here, we report the development of an immunoassay for the quantification of multiple lacritin proteoforms in human tear samples.

Methods

Basal tears collected on Schirmer test strips with anesthesia were eluted by diffusion and centrifugation under optimized conditions. Tear protein concentrations were determined, and 2.56 µg of each sample was separated by SDS-PAGE followed by western blot analysis. Blots were challenged with anti-Pep Lac N-term antibodies. Detection was with fluorescent secondary antibodies visualized by the LI-COR Odyssey CLx imaging system and quantified with standard curves of recombinant lacritin.

Results

The percent total lacritin (ng lacritin/100 ng total protein) ranged from 1.8% to 14.8%. Monomer, lacritin-c, and polymer proteoform percent total protein ranged from 1.1% to 6.3%, 0.3% to 5.4%, and 0.7% to 5.7%, respectively. Monomer lacritin was detected at concentrations of 6 to 176 µM, with lacritin-c and polymer proteoforms at 2 to 46 µM and 1 to 23 µM, respectively.

Conclusions

This assay greatly exceeds the power and sensitivity of our prior lacritin enzyme-linked immunosorbent assay that was not capable of distinguishing monomer from polymers and lacritin-c proteoforms.

Translational Relevance

A new method has been developed to quantitate multiple proteoforms of tear lacritin in preparation for analyses of samples from clinical trials.

Thrombocytopenia in pediatric patients on concurrent cannabidiol and valproic acid

In January 2019, a new plant-derived purified cannabidiol preparation, approved by the US Food and Drug Administration, became commercially available for patients ≥2 years old with Lennox-Gastaut syndrome or Dravet syndrome. Among our patients who were prescribed the new cannabidiol formulation, we observed several cases of thrombocytopenia and therefore embarked on this study. We conducted a single-center systematic chart review of all pediatric patients (<21 years old) who were prescribed cannabidiol from January to August 2019. We evaluated salient features of the patients' epilepsy syndrome, age, concurrent medications, and surveillance laboratory results before and after cannabidiol initiation. Among 87 patients, nine (10%) developed thrombocytopenia (platelet nadir range = 17 000-108 000) following initiation of cannabidiol. Each of these nine children was on combination therapy of cannabidiol with valproic acid. Whereas no children on cannabidiol without valproic acid (0/57) developed thrombocytopenia, nine of 23 treated with combination valproic acid and cannabidiol developed platelets < 110 000/µL (P < .0001). We report a novel and clinically important side effect of thrombocytopenia in one-third of patients treated concurrently with cannabidiol and valproic acid. If this finding is confirmed, clinicians should perform close monitoring for thrombocytopenia when adding cannabidiol to a regimen that includes valproic acid.

The mortality burden attributable to nontrauma fracture for privately insured adults with epilepsy

OBJECTIVE

Individuals with epilepsy have poor bone development and preservation throughout the lifespan and are vulnerable to nontrauma fracture (NTFx) and post-NTFx complications. However, no studies have examined the contribution of NTFx to mortality among adults with epilepsy. The objective was to determine whether NTFx is a risk factor for mortality among adults with epilepsy.

METHODS

Data from 2011 to 2016 were obtained from Optum Clinformatics Data Mart, a nationwide claims database from a single private payer in the United States. Diagnosis codes were used to identify adults (≥18 years old) with epilepsy, NTFx, and covariates (demographics and pre-NTFx cardiovascular disease, respiratory disease, diabetes, chronic kidney disease, cancer). Crude mortality rate per 100 person-years was estimated. Cox regression estimated hazard ratios (HRs) and 95% confidence intervals (CIs) were determined for mortality, comparing epilepsy and NTFx (EP + NTFx; n = 11 471), epilepsy without NTFx (EP without NTFx; n = 50 384), without epilepsy and with NTFx (without EP + NTFx; n = 423 041), and without epilepsy and without NTFx (without EP without NTFx; n = 6.8 million) after adjusting for covariates.

RESULTS

The 3-, 6-, and 12-month crude mortality rates were highest among EP + NTFx (12-month mortality rate = 8.79), followed by without EP + NTFx (12-month mortality rate = 4.80), EP without NTFx (12-month mortality rate = 3.06), and without EP without NTFx (12-month mortality rate = 0.47). After adjustments, the mortality rate was elevated for EP + NTFx for all time points compared to EP without NTFx (eg, 12-month HR = 1.70, 95% CI = 1.58-1.85), without EP + NTFx (eg, 12-month HR = 1.41, 95% CI = 1.32-1.51), and without EP without NTFx (eg, 12-month HR = 5.23, 95% CI = 4.88-5.60). Stratified analyses showed higher adjusted HRs of 12-month mortality for EP + NTFx for all NTFx sites (ie, vertebral column, hip, extremities), all age categories (young, middle-aged, older), and for both women and men.

SIGNIFICANCE

Among adults with epilepsy and compared to adults without epilepsy, NTFx is associated with a higher 12-month mortality rate. Findings suggest that NTFx may be a robust risk factor for mortality among adults with epilepsy.

Use of Collagen Binding Domains to Deliver Molecules to the Cornea

Purpose: The combined activity of the tear film and blinking is remarkably efficient at removal of foreign materials from the ocular surface. This has prevented the use of certain classes of drugs for the treatment of ocular surface problems. We propose that the use of peptide and protein domains that bind to moieties on the cornea could be used to deliver therapeutics by anchoring the drugs on the ocular surface long enough to provide therapeutic effects. Methods: In this study, we evaluated 4 different collagen binding domains fused to bacterial β-galactosidase for delivery of a reporter protein to collagen I and collagen IV-coated plates, rabbit corneas, and Herpes simplex virus (HSV-1) infected mouse corneas. Results: All 4 domains bound to collagen I and IV in vitro, whereas only a 10 amino acid (AA) sequence from bovine von Willebrand factor (vWF) and a 215 AA collagen binding domain from the bacterial protein ColH efficiently bound to abraded rabbit corneas. To test binding to corneas in a clinically relevant model, we assessed binding of the vWF collagen binding peptide fusions to HSV-1 infected mouse corneas. We observed that the vWF derived peptide mediated attachment to infected corneas, whereas the reporter protein without a collagen binding domain did not bind. Conclusions: Moving forward, the vWF collagen binding peptide could be used as an anchor to deliver therapeutics to prevent scarring and vision loss from damaged corneal surfaces due to disease and inflammation.

Rapid, automated mosaicking of the human corneal subbasal nerve plexus

Corneal confocal microscopy (CCM) is an in vivo technique used to study corneal nerve morphology. The largest proportion of nerves innervating the cornea lie within the subbasal nerve plexus, where their morphology is altered by refractive surgery, diabetes and dry eye. The main limitations to clinical use of CCM as a diagnostic tool are the small field of view of CCM images and the lengthy time needed to quantify nerves in collected images. Here, we present a novel, rapid, fully automated technique to mosaic individual CCM images into wide-field maps of corneal nerves. We implemented an OpenCV image stitcher that accounts for corneal deformation and uses feature detection to stitch CCM images into a montage. The method takes 3-5 min to process and stitch 40-100 frames on an Amazon EC2 Micro instance. The speed, automation and ease of use conferred by this technique is the first step toward point of care evaluation of wide-field subbasal plexus (SBP) maps in a clinical setting.

Bone Health and Endocrine Comorbidities in Pediatric Epilepsy

Antiseizure medications and dietary therapies have associated effects on the endocrine system. We provided an overview of the relationship between epilepsy treatment and bone health in children with epilepsy. Additionally, we discussed the effects of epilepsy treatment on other endocrine systems including thyroid function, growth, reproduction, and weight. The effect of epilepsy on bone health is multifactorial; there are direct and indirect effects of medication and dietary treatments as well as a decrease in physical activity, decreased sunlight exposure, decreased vitamin D levels, and additional comorbidities. Some medications have a greater effect on vitamin D and bone health than others, however all antiseizure medical treatments are associated with lower vitamin D levels in pediatric patients. We have provided practical suggestions for vitamin D surveillance in children with epilepsy as well as replacement strategies. Children with epilepsy have an increased likelihood of additional endocrine disorders including subclinical hypothyroidism, decreased growth, weight abnormalities, reproductive and sexual dysfunction. To a great extent, this is medication specific. Though more studies are needed to elucidate optimal treatment and monitoring of bone health and other endocrinopathies in children with epilepsy, it is critical that caregivers pay close attention to these issues to provide optimal comprehensive care to their patients.

Aire-deficient mice provide a model of corneal and lacrimal gland neuropathy in Sjögren's syndrome

Sjögren's syndrome (SS) is a chronic, autoimmune exocrinopathy that leads to severe dryness of the mouth and eyes. Exocrine function is highly regulated by neuronal mechanisms but little is known about the link between chronic inflammation, innervation and altered exocrine function in the diseased eyes and exocrine glands of SS patients. To gain a better understanding of neuronal regulation in the immunopathogenesis of autoimmune exocrinopathy, we profiled a mouse model of spontaneous, autoimmune exocrinopathy that possess key characteristics of peripheral neuropathy experienced by SS patients. Mice deficient in the autoimmune regulator (Aire) gene developed spontaneous, CD4+ T cell-mediated exocrinopathy and aqueous-deficient dry eye that were associated with loss of nerves innervating the cornea and lacrimal gland. Changes in innervation and tear secretion were accompanied by increased proliferation of corneal epithelial basal cells, limbal expansion of KRT19-positive progenitor cells, increased vascularization of the peripheral cornea and reduced nerve function in the lacrimal gland. In addition, we found extensive loss of MIST1+ secretory acinar cells in the Aire -/- lacrimal gland suggesting that acinar cells are a primary target of the disease, Finally, topical application of ophthalmic steroid effectively restored corneal innervation in Aire -/- mice thereby functionally linking nerve loss with local inflammation in the aqueous-deficient dry eye. These data provide important insight regarding the relationship between chronic inflammation and neuropathic changes in autoimmune-mediated dry eye. Peripheral neuropathies characteristic of SS appear to be tightly linked with the underlying immunopathological mechanism and Aire -/- mice provide an excellent tool to explore the interplay between SS-associated immunopathology and peripheral neuropathy.

Reduced Levels of Tear Lacritin Are Associated With Corneal Neuropathy in Patients With the Ocular Component of Sjögren's Syndrome

Purpose

To determine whether levels of endogenous tear protein, lacritin, are linked to altered corneal innervation and dry eye severity in patients with Sjögren's syndrome (SS).

Methods

Clinical data were obtained from 10 SS and 10 age-matched controls. Enzyme-linked immunosorbent assay was used to assess total tear lacritin extracted from Schirmer strips. Western blot was used to detect active lacritin monomer (∼25 kDa), active lacritin fragment (∼12–15 kDa), and inactive tissue transglutaminase–generated lacritin (≥40 kDa). In vivo confocal microscopy was used to assess nerve fiber density (NFD) and length (NFL). Relationships between nerve morphology and tear lacritin were examined by Spearman correlation. Diagnostic performance of tear lacritin was analyzed using receiver operating characteristic.

Results

Active tear lacritin was significantly reduced in SS patients (3.72 ± 5.62 [SS] versus 18.17 ± 4.57 ng/100 ng total tear protein [controls]; P < 0.001), while inactive lacritin was increased (84.99% ± 11.15% [SS] versus 51.04% ± 12.03% [controls]; P < 0.001). Nerve fiber density (21.70 ± 18.93 vs. 31.80 ± 9.35; P = 0.03) and NFL (4.18 ± 3.44 vs. 6.54 ± 2.47; P < 0.05) were significantly decreased in SS patients compared to controls. Reduced NFL (r = 0.74, P < 0.01) and NFD (r = 0.70, P < 0.01) were highly correlated with reduced tear lacritin. Similarly, total tear lacritin was highly correlated with Schirmers (r = 0.77, P < 0.01), ocular staining (r = −0.80, P < 0.01), and corneal sensitivity (r = 0.81, P < 0.01). Tear lacritin showed equivalent or better diagnostic performance compared to traditional clinical measures for SS (100.00% sensitivity, 85.71% specificity, cutoff = 14.50 ng/100 ng tear protein).

Conclusions

Reduced tear lacritin levels in SS patients are highly correlated with clinical signs of dry eye, as well as decreased NFD and NFL. Lacritin and its components provide excellent diagnostic sensitivity and specificity in SS.

miR-205 is a critical regulator of lacrimal gland development

The tear film protects the terrestrial animal's ocular surface and the lacrimal gland provides important aqueous secretions necessary for its maintenance. Despite the importance of the lacrimal gland in ocular health, molecular aspects of its development remain poorly understood. We have identified a noncoding RNA (miR-205) as an important gene for lacrimal gland development. Mice lacking miR-205 fail to properly develop lacrimal glands, establishing this noncoding RNA as a key regulator of lacrimal gland development. Specifically, more than half of knockout lacrimal glands never initiated, suggesting a critical role of miR-205 at the earliest stages of lacrimal gland development. RNA-seq analysis uncovered several up-regulated miR-205 targets that may interfere with signaling to impair lacrimal gland initiation. Supporting this data, combinatorial epistatic deletion of Fgf10, the driver of lacrimal gland initiation, and miR-205 in mice exacerbates the lacrimal gland phenotype. We develop a molecular rheostat model where miR-205 modulates signaling pathways related to Fgf10 in order to regulate glandular development. These data show that a single microRNA is a key regulator for early lacrimal gland development in mice and highlights the important role of microRNAs during organogenesis.

Cigarette Smoke Mediates Nuclear to Cytoplasmic Trafficking of Transcriptional Inhibitor Kaiso through MUC1 and P120-Catenin

Lung cancer is the leading cause of cancer-related death, and 87% of these deaths are directly attributable to smoking. Using three-dimensional cultures of primary human bronchial epithelial cells, we demonstrated that loss of adherens junction protein, epithelial cadherin, and the aberrant interaction of its adherens junction binding partner, p120-catenin (p120ctn), with the cytoplasmic tail of apical mucin-1 (MUC1-CT) represent initiating steps in the epithelial-to-mesenchymal transition. Smoke provoked the rapid nuclear entry of p120ctn in complex with MUC1-CT that was inhibited using the MUC1-CT inhibitory peptides, PMIP and GO-201. Nuclear entry of p120ctn promoted its interaction with transcriptional repressor kaiso and the rapid shuttling of kaiso to the cytoplasm. Nuclear exit of kaiso permitted the up-regulation of oncogenic transcription factors Fos/phospho-Ser³² Fos, FosB, Fra1/phospho-Ser²⁶⁵ Fra1, which was inhibited through suppression of p120ctn's nuclear export using leptomycin-B. These data indicated that smoke-induced nuclear-to-cytoplasmic translocation of kaiso depends on the nuclear import of p120ctn in complex with MUC1-CT and the nuclear export of kaiso in complex with p120ctn. The presence of MUC1-CT/p120ctn and p120ctn/kaiso complexes in lung squamous cell carcinoma and adenocarcinoma specimens from human patients confirms the clinical relevance of these events. Thus, enhancing kaiso's suppressor role of protumor genes by sequestering kaiso in the nucleus of a smoker's airway epithelium may represent a novel approach of treating lung cancer.

Inter-grader Agreement of the Ocular Staining Score in the Sjögren's International Clinical Collaborative Alliance (SICCA) Registry

PURPOSE

To determine the intra-observer and inter-observer reliability of a novel ocular staining score among trained ophthalmologists.

DESIGN

Reliability analysis within a prospective, observational, multicenter cohort study.

METHODS

Those enrolled in the National Institutes of Health-funded Sjögren's International Collaborative Clinical Alliance (SICCA) who presented for follow-up at the University of California San Francisco, Aravind Eye Hospital, Johns Hopkins University, and the University of Pennsylvania were included. Study participants were graded using the ocular staining score by at least 2 masked SICCA-trained ophthalmologists. The primary outcome for this study was the intraclass correlation coefficient (ICC) for the total ocular staining score. ICCs were also calculated for tear break-up time (TBUT) and conjunctival and corneal staining.

RESULTS

Total ocular staining score had an ICC of 0.91 for the right eye (95% confidence interval [CI] 0.85-0.96) and 0.90 for the left eye (95% CI 0.83-0.97). Corneal staining (right eye 0.86, 95% CI 0.76-0.93, left eye 0.90, 95% CI 0.81-0.95) and conjunctival staining (right eye 0.87, 95% CI 0.80-0.93, left eye 0.85, 95% CI 0.75-0.93) demonstrated excellent agreement. The ICC for TBUT was slightly lower (right eye 0.77, 95% CI 0.64-0.89; left eye 0.81, 95% CI 0.68-0.90).

CONCLUSIONS

Previous studies have shown that the ocular staining score is correlated with other diagnostic components of Sjögren syndrome. In this study, we demonstrate high reliability in grading among trained ophthalmologists, completing the validation of this test.

Macrophages: important players in primary Sjögren's syndrome?

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disorder characterized by immune-mediated destruction of the salivary and lacrimal glands with unknown etiology. Due to recent research utilizing human subjects as well as laboratory animal models, our understanding of the pathophysiological and immunological mechanisms of pSS has made great strides. As a consequence, targeted, immune-based therapies are gaining increased attention as the ideal way to conquer autoimmune diseases like pSS. Currently, however, there is no effective treatment to target specific immunological events or effector immune cells in the pathogenesis of pSS (discussed in other reviews of the current issue). Here, we summarize our current understanding and knowledge of the roles of monocytes/macrophages in the pathogenesis of pSS. Human studies, especially utilizing salivary gland biopsies, demonstrate the infiltration of macrophages and its correlation with disease severity. Moreover, animal model studies have shown the functional involvement of macrophages in promoting the ocular component of pSS.

Establishing PAX6 as a biomarker to detect early loss of ocular phenotype in human patients with Sjögren's syndrome

PURPOSE

Sjögren's syndrome (SS) is a common autoimmune disease that can cause aqueous-deficient dry eye and the aberrant differentiation of ocular mucosal epithelial cells toward a lineage that is pathologically keratinized and skin-like. PAX6 is the master regulator of corneal lineage commitment. Recently, we showed a functional role for PAX6 in preventing ocular surface damage induced by the proinflammatory cytokine, IL-1β, in a mouse model of SS. Here, we examine PAX6's potential as a clinical biomarker that predicts ocular surface disease in SS patients.

METHODS

Impression cytology specimens isolated from the bulbar conjunctiva of control (n = 43) and SS patients (n = 43) were used to evaluate the relative abundance of PAX6, IL-1β, and pathologic keratinization marker, small proline-rich protein (SPRR1B) by TaqMan qPCR. Transcript expression was examined relative to clinical data, including the ocular staining score (OSS), tear breakup time (TBUT), Schirmer tear test, serum autoantibody results, and the labial salivary gland focus score.

RESULTS

PAX6 expression was significantly reduced in SS patients (P = 0.010, Wilcoxon rank sum test), and highly correlated with OSS (Spearman ρ = 0.239, 95% CI 0.02-0.43; P = 0.027). The extent to which PAX6 predicted SPRR1B was largely dependent on IL-1β expression (R(2) = 0.28, P < 0.01) and elevated IL-1β predicted reduced TBUT (R(2) = 0.24, P = 0.035), low tear secretion (R(2) = 0.30, P = 0.011), and focus score (R(2) = 0.21, P = 0.002).

CONCLUSIONS

Downregulation of PAX6 in SS patients was highly associated with ocular surface damage and largely dependent on the level of inflammation. Restoration of PAX6 may provide a clinical approach to manage dry eye in SS patients.

Topical administration of lacritin is a novel therapy for aqueous-deficient dry eye disease

PURPOSE

Lacritin is a tear glycoprotein with prosecretory, prosurvival, and mitogenic properties. We examined lacritin levels in the tears of Sjögren's syndrome (SS) patients and explored the therapeutic potential of topical lacritin for the treatment of keratoconjunctivitis sicca.

METHODS

Tears from healthy controls (n = 14) and SS patients (n = 15) were assayed for lacritin using a C-terminal antibody. In a paired-eye study, autoimmune regulator (Aire) knockout (KO) mice (n = 7) were treated three times daily for 21 days with 10 μL of 4 μM lacritin (left eye) or vehicle (PBS) control (right eye). Tear secretion and ocular surface integrity were assessed at baseline and after treatment. Immunohistochemical staining of CD4+ T cells, cytokeratin-10 (K10), and cytokeratin-12 (K12) expression in the cornea and CD4+ T cell infiltration in the lacrimal glands were assessed.

RESULTS

Lacritin monomer (421.8 ± 65.3 ng [SS] vs. 655.8 ± 118.9 ng [controls]; P = 0.05) and C-terminal fragment protein (125 ± 34.1 ng [SS] vs. 399.5 ± 84.3 ng [controls]; P = 0.008) per 100 μL of tear eluate were significantly lower in SS patients. In Aire KO mice treated with lacritin, tear secretion increased by 46% (13.0 ± 3.5 mm vs. 8.9 ± 2.9 mm; P = 0.01) and lissamine green staining score significantly decreased relative to baseline (-0.417 ± 0.06 vs. 0.125 ± 0.07; P = 0.02). Expression of K10 but not K12 in the cornea was significantly decreased in lacritin-treated eyes. Focal CD4+ T cell infiltration of the lacrimal glands was significantly reduced on the lacritin-treated side versus the untreated side.

CONCLUSIONS

Lacritin is significantly reduced in the tears of SS patients. Topically administered lacritin has therapeutic potential for the treatment of aqueous-deficient dry eye disease.

Pivotal role of MUC1 glycosylation by cigarette smoke in modulating disruption of airway adherens junctions in vitro

Cigarette smoke increases the risk of lung cancer by 20-fold and accounts for 87% of lung cancer deaths. In the normal airway, heavily O-glycosylated mucin-1 (MUC1) and adherens junctions (AJs) establish a structural barrier that protects the airway from infectious, inflammatory and noxious stimuli. Smoke disrupts cell-cell adhesion via its damaging effects on the AJ protein epithelial cadherin (E-cad). Loss of E-cad is a major hallmark of epithelial-mesenchymal transition (EMT) and has been reported in lung cancer, where it is associated with invasion, metastasis and poor prognosis. Using organotypic cultures of primary human bronchial epithelial (HBE) cells treated with smoke-concentrated medium (Smk), we have demonstrated that E-cad loss is regulated through the aberrant interaction of its AJ binding partner, p120-catenin (p120ctn), and the C-terminus of MUC1 (MUC1-C). Here, we reported that even before MUC1-C became bound to p120ctn, smoke promoted the generation of a novel 400 kDa glycoform of MUC1's N-terminus (MUC1-N) differing from the 230 kDa and 150 kDa glycoforms in untreated control cells. The subsequent smoke-induced, time-dependent shedding of glycosylated MUC1-N exposed MUC1-C as a putative receptor for interactions with EGFR, Src and p120ctn. Smoke-induced MUC1-C glycosylation modulated MUC1-C tyrosine phosphorylation (TyrP) that was essential for MUC1-C/p120ctn interaction through dose-dependent bridging of Src/MUC1-C/galectin-3/EGFR signalosomes. Chemical deglycosylation of MUC1 using a mixture of N-glycosylation inhibitor tunicamycin and O-glycosylation inhibitor benzyl-α-GalNAc disrupted the Src/MUC1-C/galectin-3/EGFR complexes and thereby abolished smoke-induced MUC1-C-TyrP and MUC1-C/p120ctn interaction. Similarly, inhibition of smoke-induced MUC1-N glycosylation using adenoviral shRNA directed against N-acetyl-galactosaminyl transferase-6 (GALNT6, an enzyme that controls the initiating step of O-glycosylation) successfully suppressed MUC1-C/p120ctn interaction, prevented E-cad degradation and maintained cellular polarity in response to smoke. Thus, GALNT6 shRNA represents a potential therapeutic modality to prevent the initiation of events associated with EMT in the smoker's airway.

Spontaneous development of autoimmune uveitis Is CCR2 dependent

Development of novel strategies to treat noninfectious posterior uveitis is an ongoing challenge, in part because of limited availability of animal models that mimic the naturally occurring disease in humans. Mice deficient in the autoimmune regulatory gene Aire develop a spontaneous T-cell and macrophage-mediated autoimmune uveitis that closely recapitulates human endogenous uveitis and thus provide a useful model for mechanistic and therapeutic investigations. Lymphocytic and mononuclear infiltration of the retina in Aire knockout (KO) mice triggers the onset of uveitis from initial retinal inflammation to eventual destruction of the neuroretina with loss of photoreceptors. The C-C chemokine receptor type 2 protein (CCR2) functions in directing monocyte and macrophage migration to inflamed tissues via interaction with monocyte chemotactic proteins. Using the Aire KO mouse model, we demonstrated an essential role for CCR2 in the pathogenesis of autoimmune-mediated uveitis. Loss of functional CCR2 effectively reduced immune cell infiltration and rescued the retina from destruction. CCR2-dependent migration of bone marrow-derived cells provided the driving force for retinal inflammation, with CCR2-expressing mononuclear cells contributing to retinal damage via recruitment of CD4(+) T cells. These studies identify the CCR2 pathway as a promising therapeutic target that may prove an effective approach to treat uveitis associated with autoimmunity.

Pax6 downregulation mediates abnormal lineage commitment of the ocular surface epithelium in aqueous-deficient dry eye disease

Keratinizing squamous metaplasia (SQM) of the ocular surface is a blinding consequence of systemic autoimmune disease and there is no cure. Ocular SQM is traditionally viewed as an adaptive tissue response during chronic keratoconjunctivitis sicca (KCS) that provokes pathological keratinization of the corneal epithelium and fibrosis of the corneal stroma. Recently, we established the autoimmune regulator-knockout (Aire KO) mouse as a model of autoimmune KCS and identified an essential role for autoreactive CD4+ T cells in SQM pathogenesis. In subsequent studies, we noted the down-regulation of paired box gene 6 (Pax6) in both human patients with chronic KCS associated with Sjögren’s syndrome and Aire KO mice. Pax6 encodes a pleiotropic transcription factor guiding eye morphogenesis during development. While the postnatal function of Pax6 is largely unknown, we hypothesized that its role in maintaining ocular surface homeostasis was disrupted in the inflamed eye and that loss of Pax6 played a functional role in the initiation and progression of SQM. Adoptive transfer of autoreactive T cells from Aire KO mice to immunodeficient recipients confirmed CD4+ T cells as the principal downstream effectors promoting Pax6 downregulation in Aire KO mice. CD4+ T cells required local signaling via Interleukin-1 receptor (IL-1R1) to provoke Pax6 loss, which prompted a switch from corneal-specific cytokeratin, CK12, to epidermal-specific CK10. The functional role of Pax6 loss in SQM pathogenesis was indicated by the reversal of SQM and restoration of ocular surface homeostasis following forced expression of Pax6 in corneal epithelial cells using adenovirus. Thus, tissue-restricted restoration of Pax6 prevented aberrant epidermal-lineage commitment suggesting adjuvant Pax6 gene therapy may represent a novel therapeutic approach to prevent SQM in patients with chronic inflammatory diseases of the ocular surface.

Epilepsy characteristics and psychosocial factors associated with ketogenic diet success

The ketogenic diet is an effective therapy for childhood epilepsy, but its important impacts on families could affect successful treatment. We assessed medical and psychosocial factors associated with successful ketogenic diet treatment. A total of 23 families of patients treated with ketogenic diet completed questionnaires (30% response), including inquiries about challenges to successful dietary treatments and validated family functioning scales. Of these, 14 were considered successful (diet discontinued once the child was seizure-free or continued as clinically indicated). Family-identified challenges were food preparation time (n = 11) and that the diet was too restrictive (n = 9). Neither Medicaid insurance nor family functioning scale scores were significantly associated with successful treatment. Lower seizure frequency prior to ketogenic diet initiation (P = .02) and postdiet seizure improvement (P = .01) were associated with increased odds of success. Effective ketogenic diet treatment is dictated both by psychosocial and epilepsy-related influences. A focus on understanding the psychosocial issues may help to improve families' experiences and success with the ketogenic diet.

Rac1 and Cdc42 differentially modulate cigarette smoke-induced airway cell migration through p120-catenin-dependent and -independent pathways

The adherens junction protein p120-catenin (p120ctn) shuttles between E-cadherin-bound and cytoplasmic pools to regulate E-cadherin/catenin complex stability and cell migration, respectively. When released from the adherens junction, p120ctn promotes cell migration through modulation of the Rho GTPases Rac1, Cdc42, and RhoA. Accordingly, the down-regulation and cytoplasmic mislocalization of p120ctn has been reported in all subtypes of lung cancers and is associated with grave prognosis. Previously, we reported that cigarette smoke induced cytoplasmic translocation of p120ctn and cell migration, but the underlying mechanism was unclear. Using primary human bronchial epithelial cells exposed to smoke-concentrated medium (Smk), we observed the translocation of Rac1 and Cdc42, but not RhoA, to the leading edge of polarized and migrating human bronchial epithelial cells. Rac1 and Cdc42 were robustly activated by smoke, whereas RhoA was inhibited. Accordingly, siRNA knockdown of Rac1 or Cdc42 completely abolished Smk-induced cell migration, whereas knockdown of RhoA had no effect. p120ctn/Rac1 double knockdown completely abolished Smk-induced cell migration, whereas p120ctn/Cdc42 double knockdown did not. These data suggested that Rac1 and Cdc42 coactivation was essential to smoke-promoted cell migration in the presence of p120ctn, whereas migration proceeded via Rac1 alone in the absence of p120ctn. Thus, Rac1 may provide an omnipotent therapeutic target in reversing cell migration during the early (intact p120ctn) and late (loss of p120ctn) stages of lung carcinogenesis.

Cigarette smoke disrupts the integrity of airway adherens junctions through the aberrant interaction of p120-catenin with the cytoplasmic tail of MUC1

Adherens junctions (AJs) containing epithelial cadherin (E-cad) bound to p120-catenin (p120ctn) and β-catenin (β-ctn) play a crucial role in regulating cell-cell adhesion. Cigarette smoke abrogates cell-cell adhesion between epithelial cells by disrupting E-cad, a hallmark of epithelial-mesenchymal transition (EMT), yet the underlying mechanism remains unknown. We used an organotypic culture of primary human bronchial epithelial (HBE) cells treated with smoke-concentrated medium (Smk) to establish an essential role for the interaction between p120ctn and the cytoplasmic tail of MUC1 (MUC1-CT) in regulating E-cad disruption. Within the first 4 h of smoke exposure, apical MUC1-CT repositioned to the basolateral membrane of pseudo-stratified HBE cells, where it interacted with p120ctn. A time-dependent increase in MUC1-CT/p120ctn complexes occurred in conjunction with a time-dependent dissociation of p120ctn/E-cad/β-ctn complexes, as well as the coordinated degradation of p120ctn and E-cad. Interestingly, Smk induced a similar interaction between MUC1-CT and β-ctn, but this occurred 44 h after MUC1-CT's initial interaction with p120ctn, and well after the AJs were destroyed. Blocking MUC1-CT's interaction with p120ctn using a MUC1-CT dominant-negative peptide, PMIP, successfully abolished Smk's disruptive effects on AJs and recovered apical-basolateral polarity of HBE cells. The MUC1-CT/p120ctn interaction was highly dependent on EGFR/Src/Jnk-mediated tyrosine phosphorylation (TyrP) of MUC1-CT. Accordingly, EGFR, Src or Jnk inhibitors (AG1478, PP2, SP600125, respectively) abrogated Smk-induced MUC1-CT-TyrP, MUC1-CT/p120ctn interaction, AJ disruption, and loss of cellular polarity. Our work identified MUC1-CT and p120ctn as important regulators of epithelial polarity and cell-cell adhesion during a smoke-induced EMT-like process. Novel therapeutics designed to inhibit MUC1-CT/p120ctn complex formation may prevent EMT in the smoker's airway.

Critical involvement of macrophage infiltration in the development of Sjögren's syndrome-associated dry eye

Lymphocytic infiltration of the lacrimal gland and ocular surface in autoimmune diseases such as Sjögren's syndrome (SS) causes an aqueous-deficient dry eye that is associated with significant morbidity. Previous studies from our laboratory and others have established autoimmune regulator (Aire)-deficient mice as a useful model to examine exocrinopathy and ocular surface disease associated with SS. Consistent with human SS, autoreactive CD4(+) T cells play an indispensible role in the development of exocrine and ocular surface disease in Aire knockout mice. We report that in addition to CD4(+) T cells, a large number of macrophages infiltrate the corneal stroma, limbus, and lacrimal glands of diseased mice. Adoptive transfer of autoreactive CD4(+) T cells from Aire knockout mice led to local infiltration of macrophages and ocular surface damage in immunodeficient recipients. Depletion of local macrophages, through subconjunctival injection of clodronate liposome, attenuated lissamine green staining and improved ocular phenotype. Alternatively, systemic depletion of macrophages had no effect on ocular phenotype but led to significant improvements in lacrimal gland exocrinopathy and tear secretion. Our results suggested that autoreactive CD4(+) T cells provoked macrophage infiltration to the eye and lacrimal gland, where they played a functional role in directing the development of autoimmune dry eye.

Interleukin-1 receptor mediates the interplay between CD4+ T cells and ocular resident cells to promote keratinizing squamous metaplasia in Sjögren's syndrome

Keratinizing squamous metaplasia (SQM) of the ocular mucosal epithelium is a blinding corneal disease characterized by the loss of conjunctival goblet cells (GCs), pathological ocular surface keratinization and tissue recruitment of immune cells. Using the autoimmune regulator (Aire)-deficient mouse as a model for Sjögren's syndrome (SS)-associated SQM, we identified CD4(+) T lymphocytes as the main immune effectors driving SQM and uncovered a pathogenic role for interleukin-1 (IL-1). IL-1, a pleiotropic cytokine family enriched in ocular epithelia, governs tissue homeostasis and mucosal immunity. Here, we used adoptive transfer of autoreactive CD4(+) T cells to dissect the mechanism whereby IL-1 promotes SQM. CD4(+) T cells adoptively transferred from both Aire knockout (KO) and Aire/IL-1 receptor type 1 (IL-1R1) double KO donors conferred SQM to severe-combined immunodeficiency (scid) recipients with functional IL-1R1, but not scid recipients lacking IL-1R1. In the lacrimal gland, IL-1R1 was primarily immunolocalized to ductal epithelium surrounded by CD4(+) T cells. In the eye, IL-1R1 was expressed on local mucosal epithelial and stromal cells, but not on resident antigen-presenting cells or infiltrating immune cells. In both tissues, autoreactive CD4(+) T-cell infiltration was only observed in the presence of IL-1R1-postive resident cells. Moreover, persistent activation of IL-1R1 signaling led to chronic immune-mediated inflammation by retaining CD4(+) T cells in the local microenvironment. Following IL-1R1-dependent infiltration of CD4(+) T cells, we observed SQM hallmarks in local tissues-corneal keratinization, conjunctival GC mucin acidification and epithelial cell hyperplasia throughout the ocular surface mucosa. Proinflammatory IL-1 expression in ocular epithelial cells significantly correlated with reduced tear secretion, while CD4(+) T-cell infiltration of the lacrimal gland predicted the development of ocular SQM. Collectively, data in this study indicated a central role for IL-1 in orchestrating a functional interplay between immune cells and resident cells of SS-targeted tissues in the pathogenesis of SQM.

p120-catenin modulates airway epithelial cell migration induced by cigarette smoke

Cigarette smoking has been linked to almost all major types of cancer. Emerging evidence suggests that smoking initiates transformed cell growth and migration by disrupting cell-cell interactions in the polarized mucosal epithelium. Together with other adherens junction proteins, p120-catenin (p120ctn) maintains cell-cell adhesion through its direct interaction with E-cadherin (E-cad). Mislocalization and/or loss of p120ctn have been reported in all lung cancer subtypes and are related to poor prognosis. Here, we showed that p120ctn modulates smoke-induced cell migration via the EGFR/Src-P pathway. Chemical blockade of EGFR/Src signaling inhibited smoke-induced activation of cofilin (an actin severing protein) and promoted cell migration in the presence of p120ctn but had little effect on blocking migration in the absence of p120ctn. These data suggested that smoke-induced cell migration was mediated via an EGFR/Src-dependent signaling pathway in cells that expressed p120ctn, but upon loss of p120ctn, migration continued to occur via an alternative, EGFR/Src-independent pathway. Thus, gradual loss of membrane p120ctn with lung cancer progression may contribute to reduced effectiveness of conventional chemotherapies, such as those directed against EGFR.

Abstract B19: Cigarette smoke promotes human airway epithelial migration through temporal coordination of p120-catenin-dependent and -independent pathways

Background: Cigarette smoking has been linked to almost all major types of cancer. Emerging evidence suggests that smoking initiates transformed cell growth and migration by disrupting cell-cell interactions in the polarized mucosal epithelium. Together with other adherens junction proteins, p120-catenin (p120ctn) maintains cell-cell adhesion through its direct interaction with E-cadherin. Mislocalization and/or loss of p120ctn have been reported in all lung cancer subtypes and are related to poor prognosis. Our purpose was to investigate the initiating (intact p120ctn) and late (loss of 120ctn) events of smoke-promoted lung carcinogenesis using primary human bronchial epithelial (HBE) cells.

Methods: Wide-type and p120ctn-knockdown HBE cells exposed to cigarette smoke-conditioned medium were used to mimic the early and late progressive stages of lung cancer. Signaling cascades and cell migration under the two conditions were investigated.

Results: Src and Jnk activation by smoke were delayed in p120ctn-knockdown cells and inhibition of migration through the chemical blockade of EGFR, Src, and/or Jnk was dependent on p120ctn. In contrast, chemical inhibition of signaling via Akt (cell survival) or Erk (cell proliferation) was sufficient to block smoke-induced migration independent of p120ctn. Also independent of p120ctn was smoke's effect on the RhoGTPase, Rac1. Rac1 knockdown abolished dephosphorylation of actin binding protein, cofilin, in the presence and absence of p120ctn, indicating its essential role in smoke-induced cell migration.

Conclusions: These studies provide unprecedented insight regarding the multiple and interdependent molecular strategies employed by smoke to escape tightly regulated cellular processes such as cell migration, proliferation, and survival.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr B19.

Interleukin-1 as a phenotypic immunomodulator in keratinizing squamous metaplasia of the ocular surface in Sjögren's syndrome

Chronic inflammation of the ocular surface in Sjögren's syndrome (SS) is associated with a vision-threatening, phenotypic change of the ocular surface, which converts from a nonkeratinized, stratified squamous epithelium to a nonsecretory, keratinized epithelium. This pathological process is known as squamous metaplasia. Based on a significant correlation between ocular surface interleukin (IL)-1beta expression and squamous metaplasia in patients with SS, we investigated the role of IL-1 in the pathogenesis of squamous metaplasia in an animal model that mimics the clinical characteristics of SS. Using autoimmune-regulator (aire)-deficient mice, we assessed lacrimal gland and ocular surface immunopathology by quantifying the infiltration of major histocompatibility complex class II(+) (I-A(d+)) dendritic cells and CD4(+) T cells. We examined squamous metaplasia using a biomarker of keratinization, small proline-rich protein 1B. We used lissamine green staining as a readout for ocular surface epitheliopathy and Alcian blue/periodic acid-Schiff histochemical analysis to characterize goblet cell muco-glycoconjugates. Within 8 weeks, the eyes of aire-deficient mice were pathologically keratinized with significant epithelial damage and altered mucin glycosylation. Although knockdown of IL-1 receptor 1 did not attenuate lymphocytic infiltration of the lacrimal gland or eye, it significantly reduced ocular surface keratinization, epitheliopathy, and muco-glycoconjugate acidification. These data demonstrate a phenotypic modulation role for IL-1 in the pathogenesis of squamous metaplasia and suggest that IL-1 receptor 1-targeted therapies may be beneficial for treating ocular surface disease associated with SS.

A simplified quantitative method for assessing keratoconjunctivitis sicca from the Sjögren's Syndrome International Registry

PURPOSE

To describe, apply, and test a new ocular grading system for assessing keratoconjunctivitis sicca (KCS) using lissamine green and fluorescein.

DESIGN

Prospective, observational, multicenter cohort study.

METHODS

The National Institutes of Health-funded Sjögren's Syndrome International Registry (called Sjögren's International Collaborative Clinical Alliance [SICCA]) is developing standardized classification criteria for Sjögren syndrome (SS) and is creating a biospecimen bank for future research. Eight SICCA ophthalmologists developed a new quantitative ocular grading system (SICCA ocular staining score [OSS]), and we analyzed OSS distribution among the SICCA cohort and its association with other phenotypic characteristics of SS. The SICCA cohort includes participants ranging from possibly early SS to advanced disease. Procedures include sequenced unanesthetized Schirmer test, tear break-up time, ocular surface staining, and external eye examination at the slit lamp. Using statistical analyses and proportional Venn diagrams, we examined interrelationships between abnormal OSS (>or=3) and other characteristics of SS (labial salivary gland [LSG] biopsy with focal lymphocytic sialadenitis and focus score >1 positive anti-SS A antibodies, anti-SS B antibodies, or both).

RESULTS

Among 1208 participants, we found strong associations between abnormal OSS, positive serologic results, and positive LSG focus scores (P < .0001). Analysis of the overlapping relationships of these 3 measures defined a large group of participants who had KCS without other components of SS, representing a clinical entity distinct from the KCS associated with SS.

CONCLUSIONS

This new method for assessing KCS will become the means for diagnosing the ocular component of SS in future classification criteria. We find 2 forms of KCS whose causes may differ.

Molecular mechanism of proinflammatory cytokine-mediated squamous metaplasia in human corneal epithelial cells

PURPOSE

The cornified envelope protein small proline-rich protein 1B (SPRR1B) is a biomarker for squamous metaplasia. Proinflammatory cytokines IL-1beta and IFN-gamma are potent inducers of ocular surface keratinization and SPRR1B expression. Here the molecular mechanisms controlling SPRR1B gene expression in response to IL-1beta and IFN-gamma are elucidated.

METHODS

A 3-kb fragment of the SPRR1B gene 5'-flanking region was amplified from human chromosome 1, sequentially deleted, and cloned into a luciferase vector. Constructs were transiently transfected into human corneal epithelial cells, and activity was assessed in response to IL-1beta, IFN-gamma, or basal medium. Functional cis-elements responding to IL-1beta and IFN-gamma were characterized by site-directed mutagenesis and gel mobility shift assay. Effects of mitogen-activated protein kinases p38, ERK, and JNK were assessed using inhibitors and dominant-negative mutants. Results were validated by real-time RT-PCR.

RESULTS

The first 620 bp of the SPRR1B 5'-flanking region regulated constitutive expression and increased promoter activity in response to IL-1beta and IFN-gamma. Corresponding cis-elements for IL-1beta and IFN-gamma were bound by cAMP response element binding protein (CREB) and zinc-finger E-box binding homeobox 1 (ZEB1), respectively. Inhibition of p38 abolished the stimulatory effects of IL-1beta and IFN-gamma on SPRR1B, whereas inhibition of JNK and ERK had no effect. Dominant-negative mutants targeting p38alpha and p38beta2 blocked cytokine-induced SPRR1B promoter activity and mRNA expression.

CONCLUSIONS

SPRR1B is upregulated by the proinflammatory cytokines IL-1beta and IFN-gamma via p38 MAPK-mediated signaling pathways that lead to the activation of transcription factors CREB and ZEB1, respectively. These results identify key intracellular signaling intermediates involved in the pathogenesis of immune-mediated ocular surface squamous metaplasia.

Small proline-rich protein 1B (SPRR1B) is a biomarker for squamous metaplasia in dry eye disease

PURPOSE

Squamous metaplasia occurs in ocular surface diseases like Sjögren's syndrome (SS). It is a phenotypic change whereby epithelial cells initiate synthesis of squamous cell-specific proteins such as small proline-rich protein 1B (SPRR1B) that result in pathologic keratin formation on the ocular surface. The authors hypothesized that inflammation is a key inducer of pathologic keratinization and that SPRR1B represents an analytical biomarker for the study of the molecular mechanisms.

METHODS

Real-time quantitative RT-PCR and immunohistochemistry were used to examine SPRR1B mRNA and protein in two different mouse models of dry eye and patients with SS. Adoptive transfer of mature lymphocytes from mice lacking the autoimmune regulator (aire) gene was performed to examine the role of inflammation as an inducer of squamous metaplasia. SPRR1B expression in response to several cytokines was examined in vitro, whereas the expression of cytokines IL1beta and IFNgamma was quantified in ocular tissues of aire-deficient mice and patients with SS.

RESULTS

SPRR1B was increased across the ocular surface of mice with both desiccating stress and autoimmune-mediated, aqueous-deficient dry eye and in patients with SS. Adoptive transfer of CD4(+) T cells from aire-deficient mice to immunodeficient recipients caused advanced ocular surface keratinization. IL1alpha, IL1beta, IL6, IFNgamma, and TNFalpha induced SPRR1B expression in vitro and the local expression of IL1beta and IFNgamma was elevated in ocular tissues of patients with SS and aire-deficient mice.

CONCLUSIONS

SPRR1B is a valid biomarker for the study of the molecular mechanisms of squamous metaplasia. There is a definitive link between inflammation and squamous metaplasia in autoimmune-mediated dry eye disease, with IL1beta and IFNgamma likely acting as key participants.

Life at the front: dissecting bacterial-host interactions at the ocular surface

The ocular surface usually looks quiet, presenting a general impression of biological inactivity. Yet, the ability of the cornea to maintain health while continually exposed to environmental insults, and in the relative absence of immune strategies afforded by other body sites, reflects its complexity. Because it is critical for transparency and, therefore, our survival, the fine structure of the cornea has likely provided the driving force for the evolution of what appears to be a truly remarkable system. While several molecules are now known to participate, we are only beginning to obtain the knowledge to fully explain the mechanisms involved in corneal resistance to infection. Full explanation will require a better understanding of the interplay between microbes and various components of the ocular surface, and of the critical factors determining health as the usual outcome. To understand infectious disease, we need to consider how the scenario changes in conditions associated with susceptibility. What we learn in the process could yield a wealth of potential therapies for a wide variety of diseases of the eye and of other sites.

Exposure of human corneal epithelial cells to contact lenses in vitro suppresses the upregulation of human β-defensin-2 in response to antigens of Pseudomonas aeruginosa

Bacterial keratitis is a sight-threatening complication of contact lens wear, and Pseudomonas aeruginosa is a commonly isolated pathogen. The mechanisms by which lenses predispose the cornea to P. aeruginosa infection are unknown. Corneal epithelial cells express numerous innate defenses, some of which have bactericidal effects against P. aeruginosa. One of these is human beta-defensin-2 (hBD-2), which is upregulated in response to lipopolysaccharide or flagellin antigens. We hypothesized that prior exposure of corneal epithelia to a contact lens would interfere with upregulation of hBD-2 in response to P. aeruginosa. A novel in vitro model was used in which cultured human corneal epithelial cells were exposed to a hydrophilic contact lens for up to 3.5 days prior to challenge with a culture supernatant of P. aeruginosa antigens for 6h. Without prior lens exposure, the supernatant caused >2-fold upregulation of hBD-2 mRNA message and expression of hBD-2 peptide. Prior contact lens exposure blocked this upregulation without obvious effects on cell health. Western immunoblot and luciferase reporter studies showed that Pseudomonas-induced hBD-2 upregulation involved MyD88, c-Jun N-terminal kinase and both AP-1 and NF-kappaB transcription factors. Contact lenses did not affect surface expression of Toll-like receptor-2, -4 or -5, but did block antigen activation of AP-1, but not NF-kappaB, transcription factors. These data show that contact lenses can interfere with epithelial defense responses to bacterial antigens in vitro, and if translated in vivo, could help predispose the cornea to infection.

Interaction of Pseudomonas aeruginosa with human tear fluid components

PURPOSE

Reflex human tears bind Pseudomonas aeruginosa bacteria and prevent them from invading corneal epithelial cells. In this study, we assessed the effect of eye closure and the role of sialoglycoprotein (SG) in tears on bacterial binding and invasion.

METHODS

Human tears (reflex and closed-eye) were collected using a microcapillary tube. Reflex tears were separated into 13 fractions by high-performance liquid chromatography while high-molecular-weight components from closed-eye tears were separated into an SG/mucin fraction and a nonmucin fraction. Bacterial binding was quantified by viable counts and bacterial invasion was tested using the gentamicin survival technique.

RESULTS

Closed-eye tears bound significantly more bacteria than open-eye tears. Fractionation of reflex tears showed that 11 out of the 13 fractions bound bacteria, while all 13 fractions significantly reduced bacterial invasion of corneal epithelial cells. Surprisingly, the SG/mucin component of closed-eye tears resisted bacterial binding and had no significant effect on bacterial invasion.

CONCLUSIONS

P. aeruginosa bacteria bind more efficiently to closed-eye tears than to open-eye tears. The mechanism by which tears bind bacteria and protect against invasion does not require SG/mucin, as this fraction of closed-eye tears does not contain either activity.

Innate defense of the ocular surface

PURPOSE

The mucosal surface of the eye interfaces with the environment and can detect the presence of pathogens and irritants. The mucosal cells respond by up-regulating genes whose products either directly attack the contaminant or recruit leukocytes through the release of cytokines. Mucin, an epithelial glycoprotein, traps contaminants and aids in their removal through normal tear clearance mechanisms.

METHODS AND RESULTS

Using Northern analysis and reverse transcription-polymerase chain reaction, we have found that MUC1, a membrane-bound ocular surface mucin, is up-regulated following exposure to the products of both bacteria and activated lymphocytes. Consistent with this, MUC1 gene expression is also up-regulated in corneal epithelial cells exposed to precorneal tear film collected from two rigid contact lens wearers.

CONCLUSION

The changes in MUC1 gene expression during exposure to potential ocular irritants suggest that analysis of the molecular mechanisms mediating these changes may reveal control points amenable to drug therapy.

The Berkeley Contact Lens Extended Wear Study. Part I : Study design and conduct

OBJECTIVE

The primary aim of the Berkeley Contact Lens Extended Wear Study (CLEWS) was to test the hypotheses that extended wear of rigid gas-permeable (RGP) contact lenses with greater oxygen permeability (Dk) reduces the incidence of contact lens-associated keratopathy (CLAK) and increases the survival rate in RGP extended wear (EW). In this article we describe the clinical trial design in detail, present the results of subject recruitment and retention, and provide the baseline demographic and ocular characteristics of the CLEWS subjects, whose data will be analyzed to address the study aims in a companion article.

DESIGN

A randomized, concurrently controlled clinical trial.

INTERVENTION

Subjects were fitted with day wear (DW) high-Dk RGP lenses and then adapted to EW. Subjects who adapted to EW were then randomly assigned to either high- or medium-Dk RGP lenses for 12 months of 6-nights/week EW.

MAIN OUTCOME MEASURES

Slit-lamp assessment and grading of 17 possible keratopathies, measurement of refractive error and corneal curvature, and symptoms. Follow-up data were collected every 3 months.

RESULTS

From 545 subjects entering the DW adaptation phase, 201 adapted to EW and were randomly assigned to medium- or high-Dk lenses for 12 months of EW. The baseline characteristics of the two study groups were similar and did not differ from the 344 DW subjects who failed to adapt to EW. The distributions of oxygen transmissibility for the two study groups were disjoint, indicating that each group received distinctly different levels of hypoxia.

CONCLUSIONS

We show that CLEWS was appropriately designed to address the study hypotheses, was conducted with regard for the safety of the subjects, and adhered to rigorous protocols designed to control for bias and ensure the integrity of study data. We establish the internal validity of between-group statistical comparisons and characterize our study population to permit informed evaluation of the applicability of our results to the contact lens-wearing population in general.

The Berkeley Contact Lens Extended Wear Study. Part II : Clinical results

OBJECTIVE

To describe the principal clinical outcomes associated with 12 months use of rigid gas-permeable (RGP) extended wear contact lenses and address two primary study questions: (1) does extended wear (EW) of high oxygen transmissibility (Dk/t) RGP lenses reduce the incidence of ocular complications, and (2) does the wearing of high-Dk/t lenses reduce the rate of failure to maintain 6-night RGPEW over 12 months?

DESIGN

A randomized, concurrently controlled clinical trial.

INTERVENTION

Subjects who adapted to EW with high Dk (oxygen permeability) RGP lenses were randomized to either high Dk or medium-Dk RGP lenses for 12 months of 6-night EW.

MAIN OUTCOME MEASURES

Contact lens-associated keratopathies (CLAK), changes in refractive error and corneal curvature, and survival in EW.

RESULTS

Two hundred one subjects were randomized to medium or high-Dk lenses for 12 months of EW. Sixty-two percent of the subjects in each group completed 12 months of EW; however, the probability of failure was significantly greater for the medium-Dk group. Although the risk of complications was similar for the two groups, the number of CLAK events that led to termination were 16 versus 5 for the medium-Dk and high-Dk groups, respectively. This suggests that the type of adverse response or the inability to reverse an adverse event was different for the group being exposed to the lower oxygen dose.

CONCLUSIONS

The level of oxygen available to the cornea has a significant impact on maintaining successful RGP extended contact lens wear, but not on the initial onset of CLAK. The number of clinical events leading to termination was substantially higher for the medium Dk group, which suggests that corneal hypoxia is an important factor in the development of CLAK. Although overnight contact lens wear should be recommended with caution and carefully monitored for early detection of ocular complications, it appears that high-Dk RGP lenses can be a safe and effective treatment for correction of refractive error for most individuals who can adapt to EW.

The effects of one-hour wear of high-Dk soft contact lenses on corneal pH and epithelial permeability

PURPOSE

Previous studies have shown that 1-hour closed-eye contact lens wear with a low-Dk lens causes a significant reduction in corneal pH and an increase in epithelial permeability. In the present study, we evaluated the effects of super-high-Dk/t soft lenses on corneal epithelial barrier function and stromal pH.

METHODS

Corneal thickness was measured by optical pachometry, while epithelial permeability and stromal pH were measured by fluorophotometry. A paired-eye design was used in which one eye was randomly allocated to wear a high-oxygen-permeable soft lens (CIBAVision Focus/NIGHT & DAY (Dk/t= 175) while the other eye did not wear a lens.

RESULTS

After 1-hour closed-eye lens wear, neither the difference in corneal swelling (P = 0.206) nor the permeability (P = 0.055) between both eyes was significantly different. The mean pH values under open-eye conditions were 7.66 vs. 7.57 for the treatment and control eyes, respectively (P = 0.082), dropping to 7.27 vs. 7.25 after 1-hour eye closure (P = 0.283).

CONCLUSIONS

Although our results are limited to a 1-hour observation period, they do provide evidence that high-Dk materials may eliminate corneal acidosis and reduced epithelial barrier function that accompany closed-eye contact lens wear with lower-Dk soft lens materials.

Measurement of post-lens tear thickness

PURPOSE

A method to measure the tear film beneath a soft contact lens, referred to as post-lens tear thickness (PLTT), would have many applications to contact lens research. In this study a noninvasive technique for measuring the PLTT is presented.

METHODS

The feasibility of measuring the tear layer by optical pachometry was first assessed using a model eye. The baseline corneal thickness (B) of both eyes of 21 subjects was measured, etafilcon-A ionic disposable soft contact lenses (58% water) were inserted, and the total thickness (T) of the cornea, contact lens, and PLTT were measured. After the pachometry readings the lenses were removed and their center thickness (C) determined. The PLTT was calculated using the equation: PLTT = T-(B+C). Two sets of measurements of T were performed at 15 and 25 minutes after lens insertion. The entire procedure was repeated at a second visit.

RESULTS

The pachometry measurements of the small aqueous reservoir between the model eye and the lens closely matched those obtained by direct microscopic measurement. For human PLTT, the mean values (and 95% confidence intervals) for right eyes on visits 1 and 2 were 11 (8, 13) and 12 (10, 15) microm, respectively, and for left eyes were 12 (10, 15) and 11 microm (8, 14) microm, respectively.

CONCLUSIONS

It is possible to measure the post-lens tear thickness using optical pachometry. The variability between repeated measurements suggests that with careful sample size planning, the technique is sufficiently precise to be useful in group assessments of PLTT.

Predicting RGP daily wear success

PURPOSE

While most clinicians agree that fitting of rigid gas permeable (RGP) lenses is the preferred treatment strategy for some types of patients, many patients have difficulty adapting to full-time daily wear of these lenses. The Contact Lens Extended Wear Study (CLEWS) is a randomized, controlled clinical trial in which subjects are first adapted to full-time RGP daily wear prior to randomization to either high or medium oxygen transmissibility (Dk/L) RGP lenses for 12 months of extended wear. The CLEWS pre-randomization data provide an opportunity to examine the reasons some patients fail to adapt to RGP daily wear and to determine whether a patient's demographic, historical, and ocular characteristics can be used to predict RGP daily wear success.

METHODS

From 1,809 individuals who expressed interest in RGP lenses, 411 subjects passed the CLEWS screening criteria and were fit with high Dk lenses (mean Dk = 92 x 10(-11) [cm2/sec][mL 02/mL x mmHg]). The fitting strategy included minimum apical alignment, lid attachment, centration, and average lens diameters of 9.2 mm. Success was defined as a minimum of 14 hours per day without adverse ocular responses that would contraindicate either full-day daily wear or extended wear.

RESULTS

Of the 411 subjects, 286 (69.6%) were successful with RGP extended wear. Among the 125 failures, 50 were based on clinician findings (e.g., cornea, vision, compliance), while 75 subjects chose to discontinue wear because of unacceptable comfort or poor vision. Multivariate linear logistic regression modeling shows that younger patients with greater corneal curvature (K) and less predicted residual astigmatism have a higher probability of RGP daily wear success.

CONCLUSIONS

Our study showed that RGP lenses can be fit with a relatively high rate of success and that many of those patients who elect to discontinue RGP daily wear report unacceptable comfort as the primary reason. We propose a Bayesian statistical method that will assist clinicians in selecting those candidates for RGP daily wear who are most likely to adapt successfully.