Simplified Histologic Mucosal Healing Scheme (SHMHS) for inflammatory bowel disease: a nationwide multicenter study of performance and applicability

Claudin-2 simplifies histological assessment of activity/remission of ulcerative colitis in real-life daily practice

OBJECTIVES

Mucosal healing, and in particular histological mucosal healing, represents the new frontier as a treatment goal for inflammatory bowel diseases. However, the assessment of mucosal healing is presently somewhat limited by the numerous pathological scores available, and the lack of a global consensus on how to best assess it. For this reason, the availability of a simple and rapid test to evaluate the inflammatory state of the mucosa after treatment would be useful, especially for the daily routine.

METHODS

To exploit the above purpose, we evaluated the possible usefulness of antibodies against claudin-2, a protein of intestinal epithelium tight junctions, as a possible test to assess the presence of activity in ulcerative colitis following treatment. Biopsies from 28 patients with distal localization of the disease and clinical and endoscopic remission were tested for claudin-2 reactivity.

RESULTS

Claudin-2 reactivity was always negative in noninvolved segments and displayed a variable staining intensity in concordance with the histological activity. There was a highly significant (P < 0.0001) correlation between histological score and claudin-2 expression in the colonic segments involved (descending, sigmoid colon, and rectum).

CONCLUSIONS

Our results suggest that the use of claudin-2 in the routine daily practice could simplify and corroborate the results of current histological evaluations, especially in clinical practice and posttreatment follow-up.

Histological healing in IBD: Ready for prime time?

The main target of treatment in ulcerative colitis and Crohn's disease is to achieve a complete so-called mucosal healing. Various definitions of mucosal healing are available in literature, and the most recent ones include a combination of endoscopic and histological remission. However, the assessment of a complete histological remission is not always univocal. Absence of neutrophil infiltration in the lamina propria, together with neutrophil-mediated mucosal injuries in crypt and surface epithelium, is considered an important element to define histological remission. Although several histological scoring systems have been proposed to differentiate active vs quiescent disease and to evaluate the therapeutic efficacy, most of them are subjective and complex to employ in the daily diagnostic routine. For this reason, to simplify histologic scoring attempts have been made by introducing simplified scores, based on the evaluation of neutrophils and their mucosal localization. Artificial intelligence models are also being developed to standardize histological assessment of mucosal healing, and new biomarkers, such as claudin- 2, are emerging to simplify this latter aspect.

Claudin-2: A marker for a better evaluation of histological mucosal healing in inflammatory bowel diseases

BACKGROUND

Histological mucosal healing has become a paramount target goal to achieve in the treatment of inflammatory bowel diseases. However, there is still a lack of agreement on the best way to reach this goal, since numerous histological scores are available worldwide.

AIMS

We investigated whether claudin-2, a member of claudin family involved in the regulation of intestinal tight junctions, might be useful to assess the presence of active disease in patients with inflammatory bowel diseases.

METHODS

Biopsies from 123 patients with ulcerative colitis, Crohn's disease, infectious colitides and irritable bowel syndrome patients where tested with immunohistochemistry for claudin-2.

RESULTS

Claudin-2 appeared to be a very sensitive marker of disease activity in inflammatory bowel diseases, but was negative in the other kinds of patients. In addition, immunohistochemistry for claudin-2 showed good reproducibility by different pathologists.

CONCLUSIONS

Should these findings be confirmed in more numerous cohorts of patients, and especially in those with minimal or focal residual disease activity, this simple assessment could be useful in the routine daily practice to facilitate the task of pathologists and clinicians in the diagnosis and management of patients with inflammatory bowel diseases.

Emerging strategy towards mucosal healing in inflammatory bowel disease: what the future holds?

For decades, the therapeutic goal of conventional treatment among inflammatory bowel disease (IBD) patients is alleviating exacerbations in acute phase, maintaining remission, reducing recurrence, preventing complications, and increasing quality of life. However, the persistent mucosal/submucosal inflammation tends to cause irreversible changes in the intestinal structure, which can barely be redressed by conventional treatment. In the late 1990s, monoclonal biologics, mainly anti-TNF (tumor necrosis factor) drugs, were proven significantly helpful in inhibiting mucosal inflammation and improving prognosis in clinical trials. Meanwhile, mucosal healing (MH), as a key endoscopic and histological measurement closely associated with the severity of symptoms, has been proposed as primary outcome measures. With deeper comprehension of the mucosal microenvironment, stem cell niche, and underlying mucosal repair mechanisms, diverse potential strategies apart from monoclonal antibodies have been arising or undergoing clinical trials. Herein, we elucidate key steps or targets during the course of MH and review some promising treatment strategies capable of promoting MH in IBD.

Letter: The importance of histological assessment-a further stride in STRIDE

This article is linked to Dignass et al papers. To view these articles, visit https://doi.org/10.1111/apt.17622 and https://doi.org/10.1111/apt.17763