Pain Severity Correlates With Biopsy-Mediated Colonic Afferent Activation But Not Psychological Scores in Patients With IBS-D

INTRODUCTION

Despite heterogeneity, an increased prevalence of psychological comorbidity and an altered pronociceptive gut microenvironment have repeatedly emerged as causative pathophysiology in patients with irritable bowel syndrome (IBS). Our aim was to study these phenomena by comparing gut-related symptoms, psychological scores, and biopsy samples generated from a detailed diarrhea-predominant IBS patient (IBS-D) cohort before their entry into a previously reported clinical trial.

METHODS

Data were generated from 42 patients with IBS-D who completed a daily 2-week bowel symptom diary, the Hospital Anxiety and Depression score, and the Patient Health Questionnaire-12 Somatic Symptom score and underwent unprepared flexible sigmoidoscopy. Sigmoid mucosal biopsies were separately evaluated using immunohistochemistry and culture supernatants to determine cellularity, mediator levels, and ability to stimulate colonic afferent activity.

RESULTS

Pain severity scores significantly correlated with the daily duration of pain (r = 0.67, P < 0.00001), urgency (r = 0.57, P < 0.0005), and bloating (r = 0.39, P < 0.05), but not with psychological symptom scores for anxiety, depression, or somatization. Furthermore, pain severity scores from individual patients with IBS-D were significantly correlated (r = 0.40, P < 0.008) with stimulation of colonic afferent activation mediated by their biopsy supernatant, but not with biopsy cell counts nor measured mediator levels.

DISCUSSION

Peripheral pronociceptive changes in the bowel seem more important than psychological factors in determining pain severity within a tightly phenotyped cohort of patients with IBS-D. No individual mediator was identified as the cause of this pronociceptive change, suggesting that nerve targeting therapeutic approaches may be more successful than mediator-driven approaches for the treatment of pain in IBS-D.

Gastrointestinal peptides and small-bowel hypomotility are possible causes for fasting and postprandial symptoms in active Crohn's disease

BACKGROUND

Crohn's disease (CD) patients suffer postprandial aversive symptoms, which can lead to anorexia and malnutrition. Changes in the regulation of gut hormones and gut dysmotility are believed to play a role.

OBJECTIVES

This study aimed to investigate small-bowel motility and gut peptide responses to a standard test meal in CD by using MRI.

METHODS

We studied 15 CD patients with active disease (age 36 ± 3 y; BMI 26 ± 1 kg/m 2) and 20 healthy volunteers (HVs; age 31 ± 3 years; BMI 24 ± 1 kg/m 2). They underwent baseline and postprandial MRI scans, symptom questionnaires, and blood sampling following a 400-g soup meal (204 kcal). Small-bowel motility, other MRI parameters, and glucagon-like peptide-1 (GLP-1), polypeptide YY (PYY), and cholecystokinin peptides were measured. Data are presented as means ± SEMs.

RESULTS

HVs had significantly higher fasting motility indexes [106 ± 13 arbitrary units (a.u.)], compared with CD participants (70 ± 8 a.u.; P ≤ 0.05). Postprandial small-bowel water content showed a significant time by group interaction (P < 0.05), with CD participants showing higher levels from 210 min postprandially. Fasting concentrations of GLP-1 and PYY were significantly greater in CD participants, compared with HVs [GLP-1, CD 50 ± 8 µg/mL versus HV 13 ± 3 µg/mL (P ≤ 0.0001); PYY, CD 236 ± 16 pg/mL versus HV 118 ± 12 pg/mL (P ≤ 0.0001)]. The meal challenge induced a significant postprandial increase in aversive symptom scores (fullness, distention, bloating, abdominal pain, and sickness) in CD participants compared with HVs (P ≤ 0.05).

CONCLUSIONS

The decrease in fasting small-bowel motility noted in CD participants can be ascribed to the increased fasting gut peptides. A better understanding of the etiology of aversive symptoms in CD will facilitate identification of better therapeutic targets to improve nutritional status. This trial was registered at clinicaltrials.gov as NCT03052465.

MRI assessment of the postprandial gastrointestinal motility and peptide response in healthy humans

BACKGROUND

Feeding triggers inter-related gastrointestinal (GI) motor, peptide and appetite responses. These are rarely studied together due to methodological limitations. Recent MRI advances allow pan-intestinal, non-invasive assessment of motility in the undisturbed gut. This study aimed to develop a methodology to assess pan-intestinal motility and transit in a single session using MRI and compare imaging findings to GI peptide responses to a test meal and symptoms in a healthy volunteer cohort.

METHODS

Fifteen healthy volunteers (29.3±2.7 years and BMI 20.1±1.2 kg m^-2 ) underwent baseline and postprandial MRI scans, symptom questionnaires, and blood sampling (for subsequent GI peptide analysis, Glucagon-like peptide-1 [GLP-1], Polypeptide YY [PYY], Cholecystokinin [CCK]) at intervals for 270 minutes following a 400 g soup meal (204 kcal, Heinz, UK). Gastric volume, gall bladder volume, small bowel water content, small bowel motility, and whole gut transit were measured from the MRI scans.

KEY RESULTS

(mean±SEM) Small bowel motility index increased from fasting 39±3 arbitrary units (a.u.) to a maximum of 87±7 a.u. immediately after feeding. PYY increased from fasting 98±10 pg mL^-1 to 149±14 pg mL^-1 at 30 minutes and GLP-1 from fasting 15±3 μg mL^-1 to 22±4 μg mL^-1 . CCK increased from fasting 0.40±0.06 pmol mL^-1 to 0.94±0.1 pmol mL^-1 . Gastric volumes declined with a T_1/2 of 46±5 minute and the gallbladder contracted from a fasting volume of 19±2 mL^-1 to 12±2 mL^-1 . Small bowel water content increased from 39±2 mL^-1 to 51±2 mL^-1 postprandial. Fullness VAS score increased from 9±5 mm to 41±6 mm at 30 minutes postprandial.

CONCLUSIONS AND INFERENCES

The test meal challenge was effective in inducing a change in MRI motility end-points which will improve understanding of the pathophysiological postprandial GI response.

Increased liver fat and glycogen stores after consumption of high versus low glycaemic index food: A randomized crossover study

AIM

To investigate the acute and longer-term effects of low (LGI) versus high glycaemic index (HGI) diets on hepatic fat and glycogen accumulation and related blood measures in healthy volunteers.

METHODS

Eight healthy men (age 20.1 ± 0.4 years, body mass index 23.0 ± 0.9 kg/m² ) attended a test day before and after a 7-day macronutrient- and energy-matched HGI or LGI diet, followed by a minimum 4-week wash-out period, and then returned to repeat the intervention with the alternative diet. During test days, participants consumed either an HGI or an LGI test meal corresponding to their diet week, and liver fat [ ¹ H magnetic resonance spectroscopy (MRS)], glycogen ( ¹³ C MRS) and gastric content volume (MRI) were measured. Blood samples were obtained regularly throughout the test day to assess plasma glucose and insulin levels.

RESULTS

Plasma glucose and insulin peak values and area under the curve were significantly greater after the HGI test meal compared with the LGI test meal, as expected. Hepatic glycogen concentrations increased more after the HGI test meal ( P < .05) and peak levels were significantly greater after 7 days of HGI dietary intervention compared with those at the beginning of the intervention ( P < .05). Liver fat fractions increased significantly after the HGI dietary intervention compared with the LGI dietary intervention (two-way repeated-measures analysis of variance P ≤ .05).

CONCLUSIONS

Compared with an LGI diet, a 1-week HGI diet increased hepatic fat and glycogen stores. This may have important clinical relevance for dietary interventions in the prevention and management of non-alcoholic fatty liver disease.

A mechanistic multicentre, parallel group, randomised placebo-controlled trial of mesalazine for the treatment of IBS with diarrhoea (IBS-D)

INTRODUCTION

Immune activation has been reported in the mucosa of IBS patients with diarrhoea (IBS-D), and some small studies have suggested that mesalazine may reduce symptoms. We performed a double-blind, randomised placebo-controlled trial of 2 g mesalazine twice daily versus placebo for 3 months in patients with Rome III criteria IBS-D. Primary outcome was daily average stool frequency during weeks 11-12; secondary outcomes were abdominal pain, stool consistency, urgency and satisfactory relief of IBS symptoms.

METHODS

Participants were randomised after a 2-week baseline stool diary. All participants completed a 12-week stool diary and at the end of each week recorded the presence of 'satisfactory relief of IBS symptoms'.

RESULTS

136 patients with IBS-D (82 women, 54 men) were randomised, 10 patients withdrew from each group. Analysis by intention to treat showed the daily average stool frequency during weeks 11 and 12 were mean (SD), 2.8 (1.2) in mesalazine and 2.7 (1.9) in the placebo group with no significant group difference, (95% CI) 0.1 (-0.33 to 0.53), p=0.66. Mesalazine did not improve abdominal pain, stool consistency nor percentage with satisfactory relief compared with placebo during the last two-weeks follow-up.

CONCLUSIONS

This study does not support any clinically meaningful benefit or harm of mesalazine compared with placebo in unselected patients with IBS-D. More precise subtyping based on underlying disease mechanisms is needed to allow more effective targeting of treatment in IBS.

TRIAL REGISTRATION NUMBER

NCT01316718.

Immunosuppressive treatment in refractory chronic inflammatory demyelinating polyradiculoneuropathy. A nationwide retrospective analysis

BACKGROUND AND PURPOSE

There are other options open to patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) who are non-responders to conventional treatment, including immunosuppressive and immunomodulatory agents (IA). The aim of this study was to assess whether the use of IA is able to increase the number of responders.

METHODS

Clinical and electrophysiological data of patients with refractory CIDP, followed at 10 Italian centres, were collected, and the clinical outcome (Rankin Scale) and drug side effects (SE) for the different therapies were analysed.

RESULTS

A total of 110 patients were included. These patients underwent 158 different therapeutic procedures with IA. Seventy-seven patients were treated with azathioprine, 18 rituximab, 13 cyclophosphamide, 12 mycophenolate mofetil, 12 cyclosporine, 12 methotrexate, 11 interferon-alpha and three interferon beta-1a. The percentage of patients who responded to azathioprine (27%) was comparable to the percentage of responders to other therapies, after the exclusion of interferon beta-1a that was not effective in any of the three patients treated. The percentage of SE ranges from 8% (methotrexate) to 50% (cyclosporine).

CONCLUSIONS

One-fourth of patients, refractory to conventional treatment, showed an improvement in their disability with IA. Methotrexate had the lowest SE; cyclosporine was associated with severe SE and often led to drug discontinuation.