Conjunctival transcriptomics in ocular mucous membrane pemphigoid.

PURPOSE: Ocular Mucous Membrane Pemphigoid (OcMMP) is an orphan disease characterized by chronic autoimmune-driven conjunctival inflammation leading to progressive scarring, debilitating symptoms, and blinding sequelae. This feasibility study aims to demonstrate conjunctival genetic transcriptomic analyses as a putative tool for interrogation of pathogenic signaling pathways in OcMMP. METHODS: Conjunctival RNA profiling using the NanoString nCounter Human Fibrosis panel was undertaken on RNA extracted from conjunctival swabs obtained from 6 MMP patients (8 eyes; 4 M/2F; median age 78 [range 64-84] years); and 8 age-matched control participants (15 eyes; 3 M/5F; median age 69.5 [range 69-88] years). Data from 770 genes were analyzed with ROSALIND HyperScale architecture and stratified according to the level of clinically visible bulbar conjunctival inflammation. Normalization, fold-changes (≥+1.5-fold or ≤ -1.5-fold) and p-values adjustment (<0.05) using the Benjamini-Hochberg method were calculated. RESULTS: 93 differentially expressed genes (DEGs) were observed between OcMMP versus controls of which 48 were upregulated, and 45 downregulated. The top 4 upregulated DEGs represented fibrosis (COL3A1, COL1A1, FN1 and THBS1) while the key under-expressed genes (SCIN, HMGS2, XCL1/2) were indicative of ocular surface failure (goblet cell loss, keratinization, vulnerability to secondary infections). Forty-four pathways had a global significance score ≥2, the most significant being those related to extracellular matrix (ECM) remodeling, synthesis, and degradation. These pathways were accentuated in eyes with visible inflammation. CONCLUSIONS: NanoString methodology acquired via a simple conjunctival swab identifies profibrotic genes in OcMMP group and differentiates inflamed eyes. Longitudinal sampling and following investigative intervention will further mechanistic insight and development of novel biomarkers to monitor disease progression.

Gut Dysbiosis in Ocular Mucous Membrane Pemphigoid.

Mucous Membrane Pemphigoid is an orphan multi-system autoimmune scarring disease involving mucosal sites, including the ocular surface (OcMMP) and gut. Loss of tolerance to epithelial basement membrane proteins and generation of autoreactive T cell and/or autoantibodies are central to the disease process. The gut microbiome plays a critical role in the development of the immune system. Alteration in the gut microbiome (gut dysbiosis) affects the generation of autoreactive T cells and B cell autoantibody repertoire in several autoimmune conditions. This study examines the relationship between gut microbiome diversity and ocular inflammation in patients with OcMMP by comparing OcMMP gut microbiome profiles with healthy controls. DNA was extracted from faecal samples (49 OcMMP patients, 40 healthy controls), amplified for the V4 region of the 16S rRNA gene and sequenced using Illumina Miseq platform. Sequencing reads were processed using the bioinformatics pipeline available in the mothur v.1.44.1 software. After adjusting for participant factors in the multivariable model (age, gender, BMI, diet, proton pump inhibitor use), OcMMP cohort was found to be associated with lower number of operational taxonomic units (OTUs) and Shannon Diversity Index when compared to healthy controls. Within the OcMMP cohort, the number of OTUs were found to be significantly correlated with both the bulbar conjunctival inflammation score (p=0.03) and the current use of systemic immunotherapy (p=0.02). The linear discriminant analysis effect size scores indicated that Streptococcus and Lachnoclostridium were enriched in OcMMP patients whilst Oxalobacter, Clostridia uncultured genus-level group (UCG) 014, Christensenellaceae R-7 group and butyrate-producing bacteria such as Ruminococcus, Lachnospiraceae, Coprococcus, Roseburia, Oscillospiraceae UCG 003, 005, NK4A214 group were enriched in healthy controls (Log10 LDA score < 2, FDR-adjusted p <0.05). In conclusion, OcMMP patients have gut dysbiosis correlating with bulbar conjunctival inflammation and the use of systemic immunotherapies. This provides a framework for future longitudinal deep phenotyping studies on the role of the gut microbiome in the pathogenesis of OcMMP.

Safe Elective Surgical Practice During COVID-19 Pandemic - A Prospective Observational Study of 303 Elective Surgeries in the UK.

Aim During the COVID-19 pandemic, there has been worldwide cancellation of elective surgeries to protect patients from nosocomial viral transmission and peri-operative complications. With the unfolding situation, there is a definite need for an exit strategy to reinstate elective services. Therefore, more literature evidence supporting exit plans for elective surgical services is imperative to adopt a safe working principle. This study aims to provide evidence for safe elective surgical practice during the pandemic. Methodology This single centre, prospective, observational study included adult patients who were admitted and underwent elective surgical procedures in the trust's COVID-free environment at the Birmingham Treatment Centre between May 19 and July 14, 2020. Data were collected on demographic parameters, peri-operative variables, surgical specialities, COVID-19 reverse transcription polymerase chain reaction (RT-PCR) testing results, post-operative complications and mortality. The study also highlighted the protocols it followed for the elective services during the pandemic. Results A total of 303 patients were included with mean age of 49.9 years (SD 16.5) comprising of 59% (178) female and 41% (125) male. They were classified according to the American Society of Anaesthesiologist Grade, different surgical specialities and types of anaesthesia used. Ninety-six percent (96%) of patients were discharged on the same day. Hundred percent (100%) compliance with pre-operative COVID-19 RT-PCR testing was maintained. There was no 30-day mortality or major respiratory complications. Conclusion Careful patient selection, simultaneous involvement of the pre-assessment and anaesthetic team, strict adherence to peri-operative protocols and delivering vigilant post-operative care for COVID-19 infection can help provide safe elective surgical services if the community transmission is under reasonable control. However, it is particularly important to maintain COVID-free safe environment for such procedures.

Evaluation of full-length nanopore 16S sequencing for detection of pathogens in microbial keratitis.

BACKGROUND: Microbial keratitis is a leading cause of preventable blindness worldwide. Conventional sampling and culture techniques are time-consuming, with over 40% of cases being culture-negative. Nanopore sequencing technology is portable and capable of generating long sequencing reads in real-time. The aim of this study is to evaluate the potential of nanopore sequencing directly from clinical samples for the diagnosis of bacterial microbial keratitis. METHODS: Using full-length 16S rRNA amplicon sequences from a defined mock microbial community, we evaluated and benchmarked our bioinformatics analysis pipeline for taxonomic assignment on three different 16S rRNA databases (NCBI 16S RefSeq, RDP and SILVA) with clustering at 97%, 99% and 100% similarities. Next, we optimised the sample collection using an ex vivo porcine model of microbial keratitis to compare DNA recovery rates of 12 different collection methods: 21-gauge needle, PTFE membrane (4 mm and 6 mm), Isohelix™ SK-2S, Sugi® Eyespear, Cotton, Rayon, Dryswab™, Hydraflock®, Albumin-coated, Purflock®, Purfoam and Polyester swabs. As a proof-of-concept study, we then used the sampling technique that provided the highest DNA recovery, along with the optimised bioinformatics pipeline, to prospectively collected samples from patients with suspected microbial keratitis. The resulting nanopore sequencing results were then compared to standard microbiology culture methods. RESULTS: We found that applying alignment filtering to nanopore sequencing reads and aligning to the NCBI 16S RefSeq database at 100% similarity provided the most accurate bacterial taxa assignment. DNA concentration recovery rates differed significantly between the collection methods (p < 0.001), with the Sugi® Eyespear swab providing the highest mean rank of DNA concentration. Then, applying the optimised collection method and bioinformatics pipeline directly to samples from two patients with suspected microbial keratitis, sequencing results from Patient A were in agreement with culture results, whilst Patient B, with negative culture results and previous antibiotic use, showed agreement between nanopore and Illumina Miseq sequencing results. CONCLUSION: We have optimised collection methods and demonstrated a novel workflow for identification of bacterial microbial keratitis using full-length 16S nanopore sequencing.