Prostaglandin E-Major Urinary Metabolite Predicts Relapse in Patients With Ulcerative Colitis in Clinical Remission

Prostaglandin E-major urinary metabolites as a new biomarker for acute mesenteric ischemia

BACKGROUND

Acute mesenteric ischemia (AMI) is an emergent vascular disease caused by cessation of the blood supply to the small intestine. Despite advances in the diagnosis, intervention, and surgical procedures, AMI remains a life-threatening condition. Prostaglandin E2 major urinary metabolite (PGE-MUM), the urinary metabolite of prostaglandin E2, is known to be stable in urine and has been suggested to be a valuable biomarker for intestinal mucosal inflammation, such as ulcerative colitis. We therefore investigated whether or not PGE-MUM levels reflect the degree of ischemia in an intestinal ischemia-reperfusion model.

METHODS

Male rats were used to establish a superior mesenteric artery occlusion (SMAO) group, in which the superior mesenteric artery was clamped, and a sham group. The clamping times in the SMAO group were either 30 minutes or 60 minutes, and reperfusion times were either 3 hours or 6 hours, after which PGE-MUM values were measured.

RESULTS

The histological injury score of the SMAO (30-minute ischemia and 6-hour reperfusion group, 1.8 ± 0.4; 60-minute ischemia and 6-hour reperfusion group, 4.7 ± 0.5) and were significantly greater than that of the sham group (0.4 ± 0.7, p < 0.05). The PGE-MUM levels in the SMAO group (30-minutes ischemia and 6-hour reperfusion group, 483 ± 256; 60-minutes ischemia and 6-hour reperfusion group, 889 ± 402 ng/mL) were significantly higher than in the sham group (30-minute and 6-hour observation group, 51 ± 20; 60-minute and 6-hour observation group, 73 ± 32 ng/mL; p < 0.05). Furthermore, the PGE-MUM value was corrected by the concentration of urinary creatinine (Cr). The PGE-MUM/urinary Cr levels in the SMAO group were also significantly higher than in the sham group ( p < 0.05).

CONCLUSION

We found that intestinal ischemia-reperfusion increased urinary PGE-MUM levels depending on the ischemic time. This suggests the potential utility of PGE-MUM as a noninvasive marker of intestinal ischemia.

Neutrophil-to-lymphocyte ratio may predict clinical relapse in ulcerative colitis patients with mucosal healing

Endoscopic mucosal healing (MH) is an important treatment goal for patients with ulcerative colitis (UC). The neutrophil-to-lymphocyte ratio (NLR) reflects systemic inflammation and has been reported to be a useful predictive marker for UC. This study aimed to evaluate the clinical utility of the NLR for predicting clinical relapse in UC patients with MH. We retrospectively enrolled patients with UC who underwent colonoscopy at the Osaka City University Hospital between January 2010 and December 2010, whose Mayo Endoscopic Subscore was 0 or 1. The correlation between the incidence of relapse and demographic factors, including the NLR, was analyzed. We included 129 patients in the present study. The median NLR at the time of endoscopy was 1.98, and differences in the high NLR group and the low NLR group were compared. During a median follow-up period of 46.4 months, 58 patients (45.0%) experienced relapse. The cumulative relapse-free rate was significantly higher in the low NLR group than in the high NLR group (P = 0.03, log-rank test). Multivariate analysis identified high NLR as an independent prognostic factor for clinical relapse (hazard ratio, 1.74; 95% confidence interval, 1.02-2.98; P = 0.04). NLR is a novel and useful predictor of clinical relapse in UC patients with MH, and it can potentially be a strong indicator to determine the appropriate treatment strategy and decision-making in clinical practice.

Positioning and Usefulness of Biomarkers in Inflammatory Bowel Disease

BACKGROUND

Mucosal healing (MH) was proposed to be an ideal treatment goal for patients with inflammatory bowel disease (IBD). Instead of endoscopy to confirm MH, biomarkers are frequently used and have become an indispensable modality for the clinical examination of patients with IBD.

SUMMARY

Common biomarkers of IBD include C-reactive protein (CRP), erythrocyte sedimentation rate, antineutrophil cytoplasmic antibodies, anti-Saccharomyces cerevisiae antibodies, leucine-rich α2 glycoprotein, fecal calprotectin (FCP), and the fecal immunochemical test. Biomarkers play five major roles in the management of IBD: (1) diagnosing and distinguishing between IBD and non-IBD or ulcerative colitis and Crohn's disease; (2) predicting treatment response, especially before administrating biologics; (3) monitoring and grasping endoscopic or histological disease activity; (4) replacing endoscopy for diagnosing MH, including endoscopic and histological remission; and (5) predicting recurrence before disease activity appears through symptoms. Many reports have demonstrated the usefulness of CRP and FCP for those five roles; however, they have limitations for diagnosing MH or predicting treatment response. In general, FCP has better ability in those positions than CRP; additionally, leucine-rich α2 glycoprotein can diagnose endoscopic disease activity better than CRP. The novel biomarker, prostaglandin E-major urinary metabolite, and anti-αvβ6 antibody are expected to be noninvasive and reliable biomarkers; however, more evidence is required for future studies. Oncostatin M and microRNA are also prospects, in addition to other familiar and novel biomarkers.

KEY MESSAGES

Each biomarker has a useful feature; therefore, we should consider their features and use appropriate biomarkers for the five roles to enable noninvasive and smooth management of IBD.

Predicting Ulcerative Colitis Relapse in Clinical Remission With Fecal Immunochemical Occult Blood Test or Prostaglandin E-Major Urinary Metabolite

INTRODUCTION

The fecal immunochemical occult blood test (FIT) and prostaglandin E-major urinary metabolite (PGE-MUM) have been reported to predict the relapse of ulcerative colitis (UC) during remission. In this study, we directly compared FIT and PGE-MUM in predicting relapse and examined the effect of disease duration on these biomarkers.

METHODS

Measurements of 2 biomarkers and endoscopic examination were performed in 73 patients with UC in remission. The patients were followed up for 12 months, and clinical relapse was evaluated. In addition, we divided the patients into long-term disease duration and short-term disease duration groups for analysis.

RESULTS

Twenty-one patients (28.8%) relapsed within 12 months. FIT and PGE-MUM levels were significantly higher in the relapsed group than in the remission group. Cutoff values of FIT and PGE-MUM for predicting relapse using receiver operating characteristic analysis were 65.0 ng/mL (area under the curve [AUC]: 0.723) and 25.2 μg/g·Cr (AUC: 0.701), respectively. Patients with FIT ≥ 65.0 ng/mL and PGE-MUM ≥ 25.2 μg/g·Cr had a higher risk of clinical relapse. In the short-term disease duration group, the AUCs of FIT were larger than those of PGE-MUM using receiver operating characteristic analysis, in most instances. By contrast, the AUCs of PGE-MUM were larger than those of FIT in most cases in the long-term disease groups.

DISCUSSION

FIT and PEG-MUM were highly accurate in predicting clinical relapse in UC patients with short and long disease durations in remission, respectively.

Role of Biomarkers in the Diagnosis and Treatment of Inflammatory Bowel Disease

The number of patients with inflammatory bowel disease (IBD) is increasing worldwide. Endoscopy is the gold standard to assess the condition of IBD. The problem with this procedure is that the burden and cost on the patient are high. Therefore, the identification of a reliable biomarker to replace endoscopy is desired. Biomarkers are used in various situations such as diagnosis of IBD, evaluation of disease activity, prediction of therapeutic effect, and prediction of relapse. C-reactive protein and fecal calprotectin have a lot of evidence as objective biomarkers of disease activity in IBD. The usefulness of the fecal immunochemical test, serum leucine-rich glycoprotein, and urinary prostaglandin E major metabolite have also been reported. Herein, we comprehensively review the usefulness and limitations of biomarkers that can be used in daily clinical practice regarding IBD. To date, no biomarker is sufficiently accurate to replace endoscopy; however, it is important to understand the characteristics of each biomarker and use the appropriate biomarker at the right time in daily clinical practice.

Comparison between Prostaglandin E-major urinary metabolite and C-reactive protein levels to reflect endoscopic scores in patients with ulcerative colitis

Prostaglandin E-major urinary metabolite (PGE-MUM) and C-reactive protein (CRP) are useful biomarkers in patients with ulcerative colitis. However, whether changes in endoscopic scores over time are reflected in the values of these biomarkers has not been verified. This prospective observational study aimed to assess the relationship between changes in biomarker levels and endoscopic scores in patients with ulcerative colitis. A total of 100 colonoscopy intervals of patients with ulcerative colitis were enrolled. The relationship between variations in the Mayo endoscopic subscore over time and the accompanying changes in biomarker values were investigated. PGE-MUM levels showed a significant rise in the increased endoscopic score group (P = 0.007) and a decrease with reduced endoscopic score group (P = 0.023). CRP levels showed a significant decline with lower endoscopic values (P < 0.001); however, there was no corresponding increase with higher endoscopic scores (P = 0.141). Biomarker levels remained unchanged with stable endoscopic scores (P = 0.090 and P = 0.705). PGE-MUM levels varied significantly, and corresponded to the mucosal healing state (P = 0.019 and P = 0.009). The correlation between changes in PGE-MUM and the endoscopic score was stronger than that for CRP (r = 0.518, P < 0.001 vs. r = 0.444, P < 0.001, respectively). PGE-MUM reflected changes in endoscopic scores more accurately than CRP.