Faecal M2-pyruvate kinase: a novel, noninvasive marker of ileal pouch inflammation

Sensitivity and specificity of diagnostic modalities in pouchitis: a systematic review and meta-analysis

Restorative proctocolectomy (RPC) is the most common surgical procedure to restore gastrointestinal continuity after surgical resection of the colon and rectum. Pouchitis is a common complication with several different modalities that can be used to aid diagnosis. This systematic review and meta-analysis aimed at exploring the sensitivity and specificity these diagnostic modalities. The medical literature was searched using MEDLINE, EMBASE and EMBASE classic and PubMed from 1978 to June 2022. We calculated descriptive statistics using sensitivity, specificity, and false-positive rate of the primary studies and also their positive and negative likelihood ratios, and their diagnostic odds ratios. The screen found 5477 records with 13 studies being included. Faecal lactoferrin was found to have the highest pooled sensitivity and specificity of 98% and 88% respectively with imaging modalities coming in second and faecal calprotectin third with pooled sensitivities and specificities of 87% and 79% and 74% and 81% respectively. Faecal biomarkers particularly lactoferrin and imaging modalities may have an important role to play in diagnosing pouchitis. Importantly due to delays in availability of pouchoscopy, our data supports early ordering of these tests to help delineate from other causes. Further studies are required with larger cohort sizes to further validate these tests.

Biomarkers for the Evaluation of Pouch Inflammation: A Systematic Review

Background

Ileal pouch inflammation is a common problem following ileal pouch-anal anastomosis (IPAA). Despite its prevalence, diagnosis remains multimodal and requires endoscopy. The use of biomarkers in the prediction of and/or association with pouchitis has not been well characterized. We performed a systematic review to summarize the available evidence.

Method

A search of Ovid, MEDLINE, Cochrane Library, EMBASE, and Web of Science was conducted. Inclusion criteria included studies evaluating biomarkers for the evaluation and prediction of inflammation in patients with IPAA utilizing pouchoscopy as the gold standard. Exclusion criteria included studies on the role of the microbiome or genetic markers.

Results

A total of 28 studies, 5 case-control studies, and 23 observational cohort studies were identified. Fecal biomarkers were assessed in 23 studies, of which fecal calprotectin was the most commonly studied with sensitivities ranging from 57% to 92% and specificities from 19% to 92%. Six studies examined serum biomarkers. None of the serum biomarkers demonstrated a high sensitivity or specificity in association with pouch inflammation. Six studies described the longitudinal assessment of biomarkers. Of these studies, only three reported a predictive role of biomarkers in diagnosing endoscopic inflammation.

Conclusions

Biomarkers have emerged as a potential option to improve the management of pouchitis given the relative ease of sampling compared to pouchoscopy. Unfortunately, the evaluated biomarkers have not consistently demonstrated accuracy in predicting inflammation. Moreover, these biomarkers have not been reliably shown to be sensitive or specific in association with endoscopic pouch inflammation to merit their widespread use in clinical practice.

The role of fecal calprotectin in the diagnosis of acute pouchitis following IPAA for ulcerative colitis: a systematic clinical review

PURPOSE

Total proctocolectomy (TPC) with ileal pouch anal anastomosis (IPAA) is commonly performed for patients with refractory ulcerative colitis (UC). Pouchitis occurs in 20-50% of these patients. Fecal calprotectin is a biomarker that correlates well with the pouchitis disease activity index. However, its role in the diagnosis and management of acute pouchitis has not been thoroughly defined. The aim of this study is to review previously established cut-off values and contextualize the clinical utility of fecal calprotectin.

METHODS

Search of Medline, EMBASE, CENTRAL, and PubMed was performed. Articles were eligible if they measured fecal calprotectin in the setting of pouchitis in patients who underwent TPC with IPAA for UC. Risk of bias of the included studies was evaluated with the QUADAS-2.

RESULTS

From 117 relevant citations, seven studies with 256 patients (44.8% female, 39.88 years) met inclusion criteria. The pooled prevalence of pouchitis was 42%. The derived fecal calprotectin cut-off values ranged from 56 to 494 μg/g. The corresponding sensitivities and specificities ranged from 57 to 100% and 38 to 92%, respectively. The area under the curve was reported in three studies and ranged from 0.832 to 0.840.

CONCLUSION

Fecal calprotectin may be a reliable diagnostic tool for acute pouchitis in patients following TPC with IPAA for UC. The high sensitivity of fecal calprotectin for detection of pouchitis makes it a valuable test for ruling out pouchitis. When used in conjunction with other biomarkers, the high specificity offers value in ruling in pouchitis. However, given the complexity of this disease process, relying solely on biomarkers for diagnosis is currently unreasonable.

Surrogate Fecal Biomarkers in Inflammatory Bowel Disease: Rivals or Complementary Tools of Fecal Calprotectin?

BACKGROUND

Current noninvasive methods for assessing intestinal inflammation in inflammatory bowel disease (IBD) remain unsatisfactory. Along with C-reactive protein and erythrocyte sedimentation rate, fecal calprotectin (FC) is the standard test for assessing IBD activity, even though its specificity and accuracy are not optimal and it lacks a validated cutoff. Over the past few decades, several fecal markers released from intestinal inflammatory cells have been investigated in IBD; they are the subject of this systematic review.

METHODS

A systematic electronic search of the English literature up to April 2017 was performed using Medline and the Cochrane Library. Only papers written in English that analyzed fecal biomarkers in IBD were included. In vitro studies, animal studies, studies on blood/serum samples, and studies analyzing FC or fecal lactoferrin alone were excluded.

RESULTS

Out of 1023 citations, 125 eligible studies were identified. Data were grouped according to each fecal marker including S100A12, high-mobility group box 1, neopterin, polymorphonuclear neutrophil elastase, fecal hemoglobin, alpha1-antitrypsin, human neutrophil peptides, neutrophil gelatinase-associated lipocalin, chitinase 3-like-1, matrix metalloproteinase 9, lysozyme, M2-pyruvate kinase, myeloperoxidase, fecal eosinophil proteins, human beta-defensin-2, and beta-glucuronidase. Some of these markers showed a high sensitivity and specificity and correlated with disease activity, response to therapy, and mucosal healing. Furthermore, they showed a potential utility in the prediction of clinical relapse.

CONCLUSIONS

Several fecal biomarkers have the potential to become useful tools complementing FC in IBD diagnosis and monitoring. However, wide variability in their accuracy in assessment of intestinal inflammation suggests the need for further studies.

Serum alpha-1 antitrypsin: a noninvasive marker of pouchitis

BACKGROUND

Patients with ulcerative colitis undergoing total proctocolectomy with ileal pouch-anal anastomosis may develop pouchitis. Alpha-1-antitrypsin (AAT) is an acute phase reactant produced mainly by hepatocytes, but also locally in the gut. Data on noninvasive biomarkers of pouchitis are scarce.

METHODS

To identify biomarkers that correlate with pouch inflammation, ulcerative colitis pouch patients were prospectively recruited and underwent clinical, endoscopic, and histologic evaluations. The Pouchitis Disease Activity Index (PDAI) was calculated, and pouchitis was defined by a score ≥7. Serum and fecal AAT, C-reactive protein (CRP), fecal calprotectin, ferritin and albumin levels were measured.

RESULTS

Seventy-one ulcerative colitis pouch patients (mean age 43.8 ± 8.3 yr, 50.7% males) were included. The main indication for ileal pouch-anal anastomosis was intractable colitis (83.1%). Median serum AAT level (183.0 mg/dL, 155.1-232.0) was significantly higher in patients with a PDAI ≥7 compared with those with a PDAI <7 (167.6 mg/dL, 151.0-181.0) (P = 0.03). Serum AAT, CRP, and fecal calprotectin levels significantly correlated with PDAI scores: r = 0.583, P < 0.001; r = 0.584, P < 0.001; and r = 0.606, P = 0.001, respectively. Serum AAT and CRP levels correlated significantly (r = 0.650, P < 0.001), as did serum AAT and fecal calprotectin levels (r = 0.663, P < 0.001). Fecal AAT levels did not correlate with any tested biomarker. Receiver operating characteristic analysis demonstrated sensitivity, specificity, and positive predictive value of 55.6%, 100%, and 100%, respectively, for diagnosing pouchitis at a serum AAT cutoff level of 189 mg/dL.

CONCLUSIONS

Serum AAT is a specific noninvasive biomarker of pouchitis. AAT levels correlate with disease activity and CRP and calprotectin levels.

Clinical utility of fecal biomarkers for the diagnosis and management of inflammatory bowel disease

Diagnosis and monitoring of inflammatory bowel diseases rely on clinical, endoscopic, and radiologic parameters. Inflammatory biomarkers have been investigated as a surrogate marker for endoscopic diagnosis of inflammatory activity. Fecal inflammatory biomarkers such as calprotectin and lactoferrin are direct products of bowel inflammation and provide an accurate and noninvasive diagnostic and monitoring modality for Crohn's disease and ulcerative colitis. This report contains an overview of the currently existing literature pertaining to clinical implications of fecal biomarkers for diagnosis, monitoring, and prediction of outcomes of inflammatory bowel disease.

Long-term use of probiotics Lactobacillus and Bifidobacterium has a prophylactic effect on the occurrence and severity of pouchitis: a randomized prospective study

AIM

The aim of the study was to assess the impact of the long-term use of the composite probiotics in patients after restorative proctocolectomy.

METHOD

Forty-three patients (20 females and 23 males, aged 21 to 68 years) after restorative proctocolectomy were included in the study. After randomization patients were divided into placebo group and treatment group with oral intake of probiotic containing Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, and Bifidobacterium bifidus. Patients were investigated during initial visit and during final visit after 9 months. All patients were subjected to standard clinical and endoscopic examination with microscopic study of the specimens. Concentrations of calprotectin and pyruvate kinase isoenzyme M2-PK were determined in all cases.

RESULTS

The average severity of pouchitis and the number of patients with pouchitis significantly decrease after 9 months of the probiotic taking. The concentrations of calprotectin and pyruvate kinase isoenzyme M2-PK significantly decreased after the therapy.

CONCLUSIONS

Nine months of the probiotic treatment (Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, and Bifidobacterium bifidus) reduced the number of patients with pouchitis, decreased the PDAI score, and also decreased the fecal pyruvate kinase and calprotectin. The long-term probiotics use is safe and well accepted and can be an effective method of the pouchitis prevention.

Fecal biomarkers of intestinal health and disease in children

The identification of various fecal biomarkers has provided insight into the intestinal milieu. Most of these markers are associated with the innate immune system of the gut, apart from the more novel M2-pyruvate kinase. The innate immunity of the gut plays a role in maintaining a fine balance between tolerance to commensal bacteria and immune response to potential pathogens. It is a complex system, which comprises of multiple elements, including antimicrobial peptides (e.g., defensins, cathelicidins, lactoferrin, and osteoprotegerin), inflammatory proteins (e.g., calprotectin and S100A12), and microbial products (e.g., short-chain fatty acids). Dysfunction of any component can lead to the development of intestinal disease, and different diseases have been associated with different fecal levels of these biomarkers. Each fecal biomarker provides information on specific biological and disease processes. Therefore, stool quantification of these biomarkers provides a non-invasive method to define potential pathways behind the pathogenesis of diseases and can assist in the assessment and diagnosis of various gastrointestinal conditions. The abovementioned fecal biomarkers and their role in intestinal health and disease will be reviewed in this paper with a pediatric focus.

Fecal lactoferrin: a noninvasive fecal biomarker for the diagnosis and surveillance of pouchitis

BACKGROUND

Fecal lactoferrin is a marker of intestinal inflammation and can be assessed with a simple qualitative immunochromatographic rapid test.

OBJECTIVE

We aimed to assess the sensitivity and specificity of the test in the diagnosis of pouchitis and evaluate its clinical utility in the surveillance of inflammation of the pouch after antibiotic therapy.

DESIGN

Between October 2005 and September 2009, we recruited a consecutive series of patients who had their ileal pouch examined under a general anesthetic. Distinctions between healthy and inflamed pouches were made by the use of the Pouch Disease Activity Index. Fecal samples were taken before biopsy of the pouch, and a clinician blinded to the examination findings performed the lactoferrin test. After antimicrobial treatment, a number of patients with pouchitis had a repeat examination and lactoferrin test.

RESULTS

There were 85 (41 male) patients. Median age was 42 (interquartile range, 36-49) years. Twenty-four patients had pouchitis. The test was positive in all 24 patients with pouchitis and 5 patients with a healthy pouch. The sensitivity and specificity of the test for pouchitis was 100% and 92%. The positive predictive value was 82%. In 7 patients who received antibiotic treatment for their pouchitis, the test was able to accurately predict the resolution and/or persistence of pouchitis.

CONCLUSION

The qualitative fecal lactoferrin rapid test is a sensitive method for the diagnosis and confirmation of resolution of pouchitis. The test provides clinicians with greater confidence in the prescription of antibiotics for suspected pouchitis and its surveillance.

Faecal pyruvate kinase isoenzyme type M2 for colorectal cancer screening: A meta-analysis

AIM: To present a critical discussion of the efficacy of the faecal pyruvate kinase isoenzyme type M2 (faecal M2-PK) test for colorectal cancer (CRC) screening based on the currently available studies.

METHODS: A literature search in PubMed and Embase was conducted using the following search terms: fecal Tumor M2-PK, faecal Tumour M2-PK, fecal M2-PK, faecal M2-PK, fecal pyruvate kinase, faecal pyruvate kinase, pyruvate kinase stool and M2-PK stool.

RESULTS: Stool samples from 704 patients with CRC and from 11 412 healthy subjects have been investigated for faecal M2-PK concentrations in seventeen independent studies. The mean faecal M2-PK sensitivity was 80.3%; the specificity was 95.2%. Four studies compared faecal M2-PK head-to-head with guaiac-based faecal occult blood test (gFOBT). Faecal M2-PK demonstrated a sensitivity of 81.1%, whereas the gFOBT detected only 36.9% of the CRCs. Eight independent studies investigated the sensitivity of faecal M2-PK for adenoma (n = 554), with the following sensitivities: adenoma < 1 cm in diameter: 25%; adenoma > 1 cm: 44%; adenoma of unspecified diameter: 51%. In a direct comparison with gFOBT of adenoma > 1 cm in diameter, 47% tested positive with the faecal M2-PK test, whereas the gFOBT detected only 27%.

CONCLUSION: We recommend faecal M2-PK as a routine test for CRC screening. Faecal M2-PK closes a gap in clinical practice because it detects bleeding and non-bleeding tumors and adenoma with high sensitivity and specificity.

The diameter of the ileal J-pouch-anal anastomosis as an important risk factor of pouchitis - clinical observations

BACKGROUND

Patients' quality of life after restorative proctocolectomy depends on the potential complications. Stricture of the ileal pouch-anal anastomosis is one of the complications following restorative proctocolectomy.

MATERIAL/METHODS

We analyzed the correlation between the diameter of the anastomosis and clinical parameters, including pouchitis disease activity index (PDAI), the activity of fecal M2-pyruvate kinase and maximum tolerable volume of the pouch. The study group consisted of 31 patients in whom covering ileostomy had been closed 72 ± 50 months before enrolement to the study. Restorative proctocolectomy for ulcerative colitis or familial adenomatous polyposis coli had been performed in this group.

RESULTS

The study did not show any correlation between the diameter of the anastomosis and primary indication for surgery, the time elapsed after restoration of the bowel continuity, the activity of fecal M2-pyruvate kinase, or maximum tolerable volume. However, meaningful correlations between the stricture of the anastomosis and the presence and activity of pouchitis, together with the ileal villi atrophy, were detected.

CONCLUSIONS

Stricture of the anastomosis appears to be an important factor increasing the incidence of pouchitis, and is independent of the underlying condition and time after the operation. Dilation of the anastomosis and prevention of stricture should constitute a permanent element of postoperative follow-up.

Pouchitis and pouch dysfunction

Restorative proctocolectomy with ileal pouch-anal anastomosis has become the surgical treatment of choice for most patients with ulcerative colitis who require surgery. Although the surgical procedure offers a cure in some patients, postoperative inflammatory and noninflammatory complications are common. Pouchitis is the most common long-term complication of the procedure. Pouchitis represents a spectrum of disease processes with heterogeneous risk factors, clinical phenotypes, natural history, and prognosis. Accurate diagnosis and classification are important for proper treatment and prognosis.

Pouchitis and pouch dysfunction

Restorative proctocolectomy with ileal pouch-anal anastomosis has become the surgical treatment of choice for most patients with ulcerative colitis who require surgery. Although the surgical procedure offers a cure in some patients, postoperative inflammatory and noninflammatory complications are common. Pouchitis is the most common long-term complication of the procedure. Pouchitis represents a spectrum of disease processes with heterogeneous risk factors, clinical phenotypes, natural history, and prognosis. Accurate diagnosis and classification are important for proper treatment and prognosis.