Inflammatory bowel disease: A proposal to facilitate the achievement of an unequivocal diagnosis

Fecal Metabolites As Non-Invasive Biomarkers of Gut Diseases

Recent studies have shown the importance of the human intestinal microbiome in maintaining a healthy gastrointestinal tract, as well as in the development of pathological processes. The intestinal microbiome manifests itself primarily as fecal metabolites. In the past decade, there has been growing interest in studying its composition, which for the most part had to do with the possibility of using the metabolomic analysis in clinical diagnosis. In contrast to the comprehensive description of blood serum, urine, saliva, and cerebrospinal fluid metabolites, data on fecal metabolites is sparse. Despite the instrumental and methodological achievements in the metabolomic analysis in general, the analysis of fecal metabolome remains less well developed, mainly because of the inhomogeneity of its composition and the lack of standardized methods for collecting, processing, and analyzing fecal samples. This review summarizes data on methods for studying and describing various groups of fecal metabolites. It also assesses their potential as tools in the diagnosis of gastrointestinal diseases.

Faecal volatile organic compounds analysis using field asymmetric ion mobility spectrometry: non-invasive diagnostics in paediatric inflammatory bowel disease

BACKGROUND AND OBJECTIVES

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), remains challenging to diagnose. Diagnostic work-up carries a high burden, especially in paediatric patients, due to invasive endoscopic procedures. IBD is associated with alterations in intestinal microbiota composition. Faecal volatile organic compounds (VOCs) reflect gut microbiota composition. The aim of this study was to assess the diagnostic accuracy of faecal VOC profiling as a non-invasive diagnostic biomarker for paediatric IBD.

METHODS

In this diagnostic accuracy study performed in two tertiary centres in the Netherlands, faecal VOC profiles of 36 de novo, treatment-naïve paediatric IBD patients (23 CD, 13 UC), and 24 healthy, matched controls were measured by field asymmetric ion mobility spectrometry (Owlstone Ltd, Lonestar®, UK).

RESULTS

Faecal VOC profiles of de novo paediatric IBD patients could be differentiated from healthy controls (AUC ± 95% CI, p-value, sensitivity, specificity; 0.76 ± 0.14, p < 0.001, 79%, 78%). This discrimination from controls was observed in both CD (0.90 ± 0.10, p < 0.0001, 83%, 83%) and UC (0.74 ± 0.19, p = 0.02, 77%, 75%). VOC profiles from UC could not be discriminated from CD (0.67 ± 0.19, p = 0.0996, 65%, 62%).

CONCLUSION

Field asymmetric ion mobility spectrometry allowed for discrimination between faecal VOC profiles of de novo paediatric IBD patients and healthy controls, confirming the potential of faecal VOC analysis as a non-invasive diagnostic biomarker for paediatric IBD. This method may serve as a complementary, non-invasive technique in the diagnosis of IBD, possibly limiting the number of endoscopies needed in children suspected for IBD.

Usefulness of Different Pathological Scores to Assess Healing of the Mucosa in Inflammatory Bowel Diseases: A Real Life Study

The concept of remission for patients with inflammatory bowel diseases has recently evolved, and should also include histological healing of the mucosa, difficult to evaluate since there is no agreement on pathological scores and those available are quite complex to use in the daily routine. We evaluated the possible usefulness of a simplified pathological score to assess histological healing of the mucosa in inflammatory bowel diseases patients compared with four commonly proposed pathological scores. Slides from 24 patients (12 Crohn’s disease, 12 ulcerative colitis, age range 24–62 years), pre- and post-treatment with biological agents and displaying endoscopic remission were assessed by two pathologists. Pre- and post-treatment results and the time employed to calculate the various scores were obtained. All scores were useful to document highly significant post-treatment decreases of histological activity. However, the simplified score needed significant less time to be calculated for each slide, had high inter-rater agreement, and avoided subjectivity from the pathologists. The simplified score is easy to calculate and seems apt to document histological healing of the mucosa, in a manner similar to the more complex scores. It remains to be established whether this score could simplify the daily routinary practice in this context.

The diagnosis of inflammatory bowel disease is often unsupported in clinical practice

BACKGROUND

The diagnosis of inflammatory bowel disease can be challenging and requires the efforts of a multidisciplinary team. We performed a retrospective analysis with the aim of evaluating the adequacy of the prerequisites for arriving at an accurate histological diagnosis.

METHODS

The following parameters were considered as prerequisites for a diagnosis of inflammatory bowel disease: clinical and endoscopic data; proper sampling and handling of biopsies; and elementary microscopic lesions. We collected 345 cases from 13 centres.

RESULTS

The date of onset and treatment were available for 13% and 16% of the cases, respectively. Endoscopy information was accessible for 77% of the cases. Endoscopic mapping was completed in 13% of the cases. In no cases were the biopsies oriented on acetate strips. The diagnosis was conclusive in 47% of the cases. Activity, epithelial disruption and crypt distortion were described in 35% of the reports with a conclusive diagnosis.

CONCLUSION

Our study showed that the diagnostic prerequisites were widely unfulfilled, although approximately half of the diagnoses were conclusive for inflammatory bowel disease. Thus, in our assessment of clinical practice: (1) clinicians seldom provide suitable clinical and/or endoscopic information for a histological diagnosis and (2) histopathological diagnoses of inflammatory bowel disease are often not supported by morphology.

Endoscopic biopsy samples of naïve "colitides" patients: role of basal plasmacytosis

BACKGROUND

Although it is usually not difficult to diagnose inflammatory bowel disease (IBD) on surgical resection specimens, difficulties sometimes arise in differentiating these entities from other forms of colitis on endoscopic biopsy specimens. Basal plasmacytosis is considered as an early feature of IBD colitis, but it is rare in non-IBD colitides.

AIMS

We assessed the value of basal plasmacytosis as an individual variable in untreated patients with colitis.

PATIENTS AND METHODS

Archival slides of patients with untreated colitis (66 IBD and 49 non-IBD) and 20 controls with complete (from the terminal ileum to the rectum) endoscopic biopsy sampling were evaluated blindly for the presence of basal plasmacytosis and a possible association with the presence of eosinophils in the same anatomical location.

RESULTS

Overall, basal plasmacytosis was present in at least one anatomical segment in 58% of cases, and it was always present in patients with IBD, whereas it was sparsely found (9%) in patients with other colitides and in controls. Basal plasmacytosis in three or more segments had more than 80% probability for a patient to be classified as IBD, with the segmental distribution being different between ulcerative colitis and Crohn's disease. Additionally, basal plasmacytosis was always accompanied by eosinophils intermingled with plasma cells in the same anatomical position.

CONCLUSION

As an individual feature, basal plasmacytosis (accompanied by eosinophils) is a strong feature suggesting IBD, particularly when present in three or more colonic segments. This fact may be useful in the evaluation of endoscopic biopsies from patients with "colitis".