Near infrared readouts offer sensitive and rapid assessments of intestinal permeability and disease severity in inflammatory bowel disease models

Abstract

Intestinal permeability and neutrophil activity are closely linked to inflammatory bowel disease (IBD) pathophysiology. Here we discuss two techniques for assessing permeability and neutrophil activity in mouse iBD models using near infrared (niR) detection. to address the limitation of visible light readouts-namely high background-IRDye 800CW was used to enable rapid, non-terminal measurements of intestinal permeability. the increased sensitivity of niR readouts for colon permeability is shown using dextran sulfate sodium (DSS) and anti-CD40 murine colitis models in response to interleukin-22 immunoglobulin Fc (IL22Fc) fusion protein and anti-p40 monoclonal antibody treatments, respectively. in addition to enhanced permeability, elevated levels of neutrophil elastase (NE) have been reported in inflamed colonic mucosal tissue. Activatable NIR fluorescent probes have been extensively used for disease activity evaluation in oncologic animal models, and we demonstrate their translatability using a NE-activatable reagent to evaluate inflammation in DSS mice. Confocal laser endomicroscopy (CLE) and tissue imaging allow visualization of spatial NE activity throughout diseased colon as well as changes in disease severity from IL22Fc treatment. Our findings with the 800CW dye and the NE probe highlight the ease of their implementation in preclinical IBD research. Ulcerative colitis (UC) and Crohn's disease (CD) are two main forms of both acute and chronic inflammatory bowel diseases (IBD) with complex disease etiology. While multiple anti-inflammatory treatment strategies are available to patients, there is active interest in the development of therapeutic strategies that improve epithelial repair and barrier function to reduce pro-inflammatory burdens 1-3. Several clinical studies suggest alterations in paracellular permeability and tight junction functions are key events in the pathogenesis of IBD 3-5. In addition to traditional readouts of disease severity such as body weight, colon length, and pathology score, screening and assessment of intestinal tight junction permeability is an increasingly important measurement in animal colitis models. Ratiometric measurements of sugar concentrations in urine provide gastrointestinal permeability data in the clinic, but data are highly variable and require significant urine collection at multiple timepoints 6,7. Other strategies utilize small molecule such as radiolabeled EDTA but require ionizing radiation and are more costly 8. Due to ease of handling, in vivo assessment of intestinal epithelial permeability in pre-clinical models largely relies on measuring serum fluorescein isothiocyanate (FITC)-labeled dextrans that are orally gavaged. However, 4 kDa FITC-dextran detection has limited sensitivity due to high blood autofluorescence and may prevent accurate differentiation between treatment groups in dose-response experiments, where absolute differences in fluorescence intensity may be low and/or near the limit of detection. Low molar absorptivity in addition to high

Gut microbiota of Parkinson’s disease in an appendectomy cohort: a preliminary study

“…Reportedly, intestinal permeability and neutrophil activity are closely linked to the pathophysiology of inflammatory bowel disease (IBD) 26 . In a bacterial culture of biopsies from ileum and ascending and sigmoid colon collected from patients with IBD, Enterobacteriaceae (primarily E. coli ) and Bacteroides were the predominant aerobes and anaerobes, respectively 27 .…”

Concomitant ankylosing spondylitis can increase the risk of biologics or small molecule therapies to control inflammatory bowel disease

“…The higher intestinal permeability was correlated with the higher severity of experimental colitis in the murine model. [29][30][31] The degree of colitis was influenced by the deficiency of structural proteins contributing to gut integrity or cytokines/chemokines related to intestinal inflammation and barrier function. The high intestinal permeability was also found in patients with AS and their first-degree relatives, meaning that abnormal intestinal permeability is likely to be genetically related.…”

Minimally invasive biomarkers in human and non‐human primate evolutionary biology: Tools for understanding variation and adaptation

“…Evidence from fields outside of HEB suggests that variation in gut absorptive capacity and permeability are substantial among humans (Damms‐Machado et al, 2017 ; Dutta et al, 2019 ; Li & Atkinson, 2015 ) as well as NHPs (Bethune et al, 2008 ; Garg et al, 2015 ; Zhang et al, 2020 ). One primary source of variation globally among humans appears to be environmental enteric dysfunction (EED)—an acquired condition characterized by microbial translocation across the small intestine and reduced absorptive capacity—that is common in contexts of high pathogen exposure (Kosek, 2017 ; Marie et al, 2018 ; Mbuya & Humphrey, 2016 ; Prendergast et al, 2014 ).…”