Quantitative Assessment of Anterior Segment Inflammation in a Rat Model of Uveitis Using Spectral- Domain Optical Coherence Tomography

Citation: Pepple KL, Choi WJ, Wilson L, Van Gelder RN, Wang RK. Quantitative assessment of anterior segment inflammation in a rat model of uveitis using spectral-domain optical coherence tomography. Invest Ophthalmol Vis Sci. 2016;57:3567-3575. DOI:10.1167/iovs.16-19276 PURPOSE. To develop anterior segment spectral-domain optical coherence tomography (SD-OCT) and quantitative image analysis for use in experimental uveitis in rats. METHODS. Acute anterior uveitis was generated in Lewis rats. A spectral domain anterior segment OCT system was used to image the anterior chamber (AC) and ciliary body at baseline and during peak inflammation 2 days later. Customized MatLab image analysis algorithms were developed to segment the AC, count AC cells, calculate central corneal thickness (CCT), segment the ciliary body and zonules, and quantify the level of ciliary body inflammation with the ciliary body index (CBI). Images obtained at baseline and during peak inflammation were compared. Finally, longitudinal imaging and image analysis was performed over the 2-week course of inflammation. RESULTS. Spectral-domain optical coherence tomography identifies structural features of inflammation. Anterior chamber cell counts at peak inflammation obtained by automated image analysis and human grading were highly correlated (r ¼ 0.961), and correlated well with the histologic score of inflammation (r ¼ 0.895). Inflamed eyes showed a significant increase in average CCT (27 lm, P ¼ 0.02) and an increase in average CBI (P < 0.0001). Longitudinal imaging and quantitative image analysis identified a significant change in AC cell and CBI on day 2 with spontaneous resolution of inflammation by day 14. CONCLUSIONS. Spectral-domain optical coherence tomography provides high-resolution images of the structural changes associated with anterior uveitis in rats. Anterior chamber cell count and CBI determined by semi-automated image analysis strongly correlates with inflammation, and can be used to quantify inflammation longitudinally in single animals

Uveitis Therapy With Shark Variable Novel Antigen Receptor Domains Targeting Tumor Necrosis Factor Alpha or Inducible T-Cell Costimulatory Ligand

Acknowledgments Supported by an unrestricted departmental grant from Research to Prevent Blindness (New York, NY), NEI K08EY023998 (KLP), P30-EY001730 (RVG; Bethesda, MD), by a grant from Elasmogen Limited (RVG), and with support from the Mark J. Daily, MD Research Fund (RVG, KLP).Peer reviewedPublisher PD

Clinical impairment in premanifest and early Huntington's disease is associated with regionally specific atrophy.

TRACK-HD is a multicentre longitudinal observational study investigating the use of clinical assessments and 3-Tesla magnetic resonance imaging as potential biomarkers for future therapeutic trials in Huntington's disease (HD). The cross-sectional data from this large well-characterized dataset provide the opportunity to improve our knowledge of how the underlying neuropathology of HD may contribute to the clinical manifestations of the disease across the spectrum of premanifest (PreHD) and early HD. Two hundred and thirty nine gene-positive subjects (120 PreHD and 119 early HD) from the TRACK-HD study were included. Using voxel-based morphometry (VBM), grey and white matter volumes were correlated with performance in four domains: quantitative motor (tongue force, metronome tapping, and gait); oculomotor [anti-saccade error rate (ASE)]; cognition (negative emotion recognition, spot the change and the University of Pennsylvania smell identification test) and neuropsychiatric measures (apathy, affect and irritability). After adjusting for estimated disease severity, regionally specific associations between structural loss and task performance were found (familywise error corrected, P < 0.05); impairment in tongue force, metronome tapping and ASE were all associated with striatal loss. Additionally, tongue force deficits and ASE were associated with volume reduction in the occipital lobe. Impaired recognition of negative emotions was associated with volumetric reductions in the precuneus and cuneus. Our study reveals specific associations between atrophy and decline in a range of clinical modalities, demonstrating the utility of VBM correlation analysis for investigating these relationships in HD

Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation

Urinary β2-Microglobulin Testing in Pediatric Uveitis: A Case Report of a 9-Year-Old Boy with Renal and Ocular Sarcoidosis

We present here a case of a 9-year-old boy with bilateral anterior uveitis and an extremely elevated urinary β2-microglobulin level (25,400 μg/l). The normal range for urinary excretion of β2-microglobulin is 0-300 μg/l. In patients with tubulointerstitial nephritis and uveitis syndrome (TINU), elevations typically range from 1,260 to 5,160 μg/l. Renal biopsy was pursued, and significant granulomatous interstitial nephritis consistent with sarcoidosis was identified. Systemic immune modulation was required for control of ocular inflammation. This case highlights the importance of urinary β2-microglobulin testing in the pediatric patient uveitis population, and additionally the need to pursue kidney biopsy in the presence of extreme elevations in urinary β2-microglobulin to differentiate between TINU and sarcoidosis

A Genetic Screen in Drosophila for Genes Interacting With senseless During Neuronal Development Identifies the Importin moleskin

Senseless (Sens) is a conserved transcription factor required for normal development of the Drosophila peripheral nervous system. In the Drosophila retina, sens is necessary and sufficient for differentiation of R8 photoreceptors and interommatidial bristles (IOBs). When Sens is expressed in undifferentiated cells posterior to the morphogenetic furrow, ectopic IOBs are formed. This phenotype was used to identify new members of the sens pathway in a dominant modifier screen. Seven suppressor and three enhancer complementation groups were isolated. Three groups from the screen are the known genes Delta, lilliputian, and moleskin/DIM-7 (msk), while the remaining seven groups represent novel genes with previously undefined functions in neural development. The nuclear import gene msk was identified as a potent suppressor of the ectopic interommatidial bristle phenotype. In addition, msk mutant adult eyes are extremely disrupted with defects in multiple cell types. Reminiscent of the sens mutant phenotype, msk eyes demonstrate reductions in the number of R8 photoreceptors due to an R8 to R2,5 fate switch, providing genetic evidence that Msk is a component of the sens pathway. Interestingly, in msk tissue, the loss of R8 fate occurs earlier than with sens and suggests a previously unidentified stage of R8 development between atonal and sens

Use of En Face Swept-Source Optical Coherence Tomography Angiography in Identifying Choroidal Flow Voids in 3 Patients With Birdshot Chorioretinopathy.

Importance Patients with birdshot chorioretinopathy (BSCR) can experience a delay in diagnosis owing to the challenges of identifying the condition prior to evolution of characteristic choroidal scars. An objective, noninvasive method for detecting early lesions in BSCR might have an effect on preventing vision loss in these patients. Objective To test the feasibility of swept-source optical coherence tomography angiography (SS-OCTA) in the detection of BSCR choroidal lesions and to use en face image analysis of choroidal layers to localize lesion depth. Design, Setting, and Participants Prospective, longitudinal, observational case series of 3 patients diagnosed as having BSCR at 1 of 2 tertiary care uveitis centers between August 2017 and October 2017. Exposures Widefield SS-OCTA and indocyanine green angiography (ICGA). Main Outcomes and Measures En face SS-OCTA slabs through the choroid were evaluated for the presence of flow voids corresponding to hypocyanescent lesions by ICGA. Baseline and posttreatment images were compared. Results Six eyes of 3 patients with previously undiagnosed and untreated BSCR were imaged at baseline and after initiation of immune modulation treatment. Two patients had a history of recent-onset BSCR, and the third patient had a history of chronic untreated disease of at least 5 years' duration. All patients were white and between the ages of 50 and 67 years. All eyes demonstrated multiple flow voids on en face SS-OCTA images that corresponded with hypocyanescent lesions by ICGA. Analysis of serial depth en face SS-OCTA flow images identified that in the acute-onset patients, flow voids were located adjacent to large vessels in the Haller layer and regressed with treatment. In the patient with chronic, untreated disease, full-thickness choroidal flow voids were identified that did not regress with treatment. Conclusions and Relevance For these 3 patients, SS-OCTA provided a noninvasive method for identifying early BSCR lesions previously visible only with ICGA. The depth information provided by SS-OCTA suggests acute lesions originate in the Haller layer, and that in the absence of treatment, damage extends up thorough the superficial choroid, and ultimately to the retinal pigment epithelium and retina. Swept-source OCTA may represent a new and noninvasive method for detecting and monitoring disease activity in BSCR

Automated Quantification of Choriocapillaris Lesion Area in Patients with Posterior Uveitis.

PURPOSE To validate a custom algorithm for automated identification and quantification of clinically relevant inflammatory choriocapillaris (CC) lesions from en face swept source optical coherence tomography (SS-OCTA) images. DESIGN observational case series METHODS: : Twenty eyes of 14 patients with posterior uveitis were imaged using the PLEX® Elite 9000. The machine-generated en face OCTA CC slabs were exported to MATLAB where a custom algorithm performed unsupervised lesion boundary delineation and area quantification. Lesions identified by the algorithm (AG) were compared to those identified by two masked human graders (HG1 and HG2), using the Sørensen-Dice coefficient (DSC) and intraclass correlation coefficient (ICC). Intra-grader and intra-visit reliability were determined by coefficient of variation (CV) and DSC. RESULTS The AG demonstrated excellent agreement with both HGs in determination of lesion area (HG1 vs. AG ICC 0.92, 95% CI 0.81-0.97, HG2 vs. AG ICC 0.91, 95% CI 0.78-0.97). The AG demonstrated good spatial overlap (DSC≥0.70) with both HGs in 14/20 (70%) eyes and at least one HG in 16/20 (80%) eyes. Poor spatial overlap (DSC between 0.31 and 0.69) was associated with the presence of a choroidal neovascular membrane and low contrast lesion boundaries. Intra-visit repeatability for the AG was superior to both HGs (CV 2.6% vs >5%). CONCLUSION This custom algorithm demonstrated a high degree of agreement with human graders in identification of inflammatory CC lesions, and outperformed human graders in reproducibility. Automated CC lesion delineation will support the development of objective and quantitative biomarker of disease activity in patients with posterior uveitis