Evaluation of Optimal Biopsy Location for Assessment of Histological Activity, Transcriptomic and Immunohistochemical Analyses in Patients With Active Crohn's Disease

Gregor Novak; Toer Stevens; Tanja Van Viegen; Peter Bossuyt; Borut Štabuc; Jenny Jeyarajah; Guangyong Zou; Ingrid C. Gaemers; Trevor D. McKee; Fred Fu; Lisa M. Shackelton; Reena Khanna; Gijs R. van den Brink; William J. Sandborn; Brian G. Feagan; Rish K. Pai; Vipul Jairath; Niels Vande Casteele; Geert D'Haens

Disclosures

Aliment Pharmacol Ther. 2019;49(11):1401-1409. 

In This Article

Abstract and Introduction

Abstract

Background: The appropriate location for biopsy procurement relative to an ulcer in active Crohn's disease is unknown.

Aim: To explore the relationship between biopsy location, histological disease activity, proinflammatory gene expression and the presence of inflammatory cells.

Methods: Fifty-one patients with Crohn's disease and ulcers >0.5 cm diameter in the colon and/or ileum were prospectively enrolled at three centres. Biopsies were obtained from 0 mm, 7 to 8 mm and 21 to 24 mm from the edge of the largest ulcer. Histological activity was blindly assessed with the Global Histological Disease Activity Score, the Robarts Histopathology and Nancy Histological indices. Messenger ribonucleic acid (mRNA) levels for interleukins-6, -8 and -23 (p19 and p40 subunits), CD31 and S100A9 were measured using quantitative polymerase chain reaction. The number of CD3+, CD68+ and myeloperoxidase-positive cells was quantified by immunohistochemistry. Data were analysed using mixed models with location and segment as fixed effects and patients as random effect to account for correlation among segments within a patient.

Results: Histological disease activity scores (P < 0.0001), proinflammatory gene expression levels (P < 0.005) and numbers of myeloperoxidase-positive cells (P < 0.0001) were highest in biopsies from the ulcer edge in the colon and ileum, with decreasing gradients observed with distance from the edge (P < 0.05). No differences between colonic and ileal samples were detected for the parameters measured at any location.

Conclusions: Biopsies from the ulcer edge in patients with Crohn's disease yielded the greatest histological disease activity and mRNA levels and had similar readouts in the colon and ileum. Research is needed to confirm this conclusion for other measures.

Introduction

With the evolution of more effective medical therapies over the last decade, treatment goals for Crohn's disease have advanced beyond symptom control to prevention of bowel damage and associated complications such as intestinal strictures, fistulae and abscesses. Several studies have demonstrated associations between endoscopic response and remission and decreased rates of clinical relapse, hospitalisation and surgery.[1–6] Accordingly, endoscopic remission, defined as resolution of ulcers at ileocolonoscopy has been proposed as a treatment target in the Selecting Therapeutic in Inflammatory Bowel Disease (STRIDE) consensus recommendations.[7] However, persistent histological inflammation is present in up to one-third of biopsies from Crohn's disease patients with endoscopically healed mucosa.[8–10] Thus, a key question is whether endoscopic remission is sufficient to prevent disease relapse and future complications, or whether histological remission should additionally be used to define mucosal healing.[9]

To determine the potential value of histology in Crohn's disease management and assessment of response to therapy, endoscopic mucosal biopsies must be collected in a consistent and reproducible manner. Definition of an optimal biopsy location is confounded by the patchy nature of Crohn's disease, in which regions of normal-appearing mucosa alternate between areas of inflammation and ulcers.[9,10] The need for standardisation of biopsy procurement has been emphasised in the literature and is especially important during drug development to optimally define response to therapy,[10,11] as demonstrated by recent clinical trials in Crohn's disease.[12,13] In patients with visible ulcers, the traditional dogma for assessment of histologic disease activity is to procure biopsies from ulcerated edges. However, to our knowledge no data from empiric studies are available to justify this guidance. Similarly, no standards exist to guide sampling for gene expression[14] or immunohistochemical analyses in Crohn's disease. Accordingly, we conducted a prospective study in patients with Crohn's disease-related ileocolonic ulcers to assess histological disease activity, messenger ribonucleic acid (mRNA) expression levels of proinflammatory genes and number of lamina propria inflammatory cells according to biopsy location relative to an ulcer edge.

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