O. Borrelli

Gut-associated bacterial microbiota in paediatric patients with inflammatory bowel disease

Background: Clinical and experimental observations in animal models indicate that intestinal commensal bacteria are involved in the initiation and amplification of inflammatory bowel disease (IBD). No paediatric reports are available on intestinal endogenous microflora in IBD. Aims: To investigate and characterise the predominant composition of the mucosa-associated intestinal microflora in colonoscopic biopsy specimens of paediatric patients with newly diagnosed IBD. Methods: Mucosa-associated bacteria were quantified and isolated from biopsy specimens of the ileum, caecum and rectum obtained at colonoscopy in 12 patients with Crohn’s disease, 7 with ulcerative colitis, 6 with indeterminate colitis, 10 with lymphonodular hyperplasia of the distal ileum and in 7 controls. Isolation and characterisation were carried out by conventional culture techniques for aerobic and facultative-anaerobic microorganisms, and molecular analysis (16S rRNA-based amplification and real-time polymerase chain reaction assays) for the detection of anaerobic bacterial groups or species. Results: A higher number of mucosa-associated aerobic and facultative-anaerobic bacteria were found in biopsy specimens of children with IBD than in controls. An overall decrease in some bacterial species or groups belonging to the normal anaerobic intestinal flora was suggested by molecular approaches; in particular, occurrence of Bacteroides vulgatus was low in Crohn’s disease, ulcerative colitis and indeterminate colitis specimens. Conclusion: This is the first paediatric report investigating the intestinal mucosa-associated microflora in patients of the IBD spectrum. These results, although limited by the sample size, allow a better understanding of changes in mucosa-associated bacterial flora in these patients, showing either a predominance of some potentially harmful bacterial groups or a decrease in beneficial bacterial species. These data underline the central role of mucosa-adherent bacteria in IBD.

Contrast enhanced magnetic resonance imaging of the terminal ileum in children with Crohn’s disease

Background and aims: Recently, magnetic resonance imaging (MRI) has been introduced in the diagnosis of patients with inflammatory bowel disease (IBD). However, it is still rarely reported in paediatric IBD. We studied the diagnostic value of gadolinium enhanced MRI in revealing inflammation of the distal ileum in children with Crohn’s disease (CD) and in differentiating them from patients with other inflammatory diseases of the gut. MRI was performed using a polyethylene glycol (PEG) solution as oral contrast agent to distend the small bowel (CE-PEG-MRI). Subjects and methods: Seventy five consecutive patients (median age 13.6 years, range 8–17) with suspected CD underwent ileocolonoscopy with biopsy and CE-PEG-MRI. CD activity was measured by the paediatric Crohn’s disease activity index (PCDAI). CE-PEG-MRI was evaluated with an overall score calculated, taking into account both wall thickness and contrast enhancement. Results: Active CD with distal ileitis was diagnosed in 26 cases, active ulcerative colitis (UC) in 18, and spondyloarthropathy and indeterminate ileocolitis in 11; 20 children served as controls. In all CD patients, CE-PEG-MRI revealed a marked ileal involvement with increased wall thickness and parietal contrast enhancement and showed a high concordance with endoscopy and histology, whereas the test was negative in all controls. Of the 18 UC patients, CE-PEG-MRI was negative in 15 and showed a mild parietal contrast enhancement of the terminal ileum in only three of seven patients with backwash ileitis. Among the group of spondyloarthropathy patients, six had mucosal erosions and five mild superficial ileitis: CE-PEG-MRI was negative in four and revealed only mild parietal contrast enhancement of the ileal wall in seven. CE-PEG-MRI did not show an increase in wall thickness of the distal ileum in any of the UC or spondyloarthropathy patients. The sensitivity and specificity of CE-PEG-MRI related to the presence of erosive ileitis, as documented by endoscopy, were 84% and 100%, respectively. In addition, the test correlated markedly with endoscopy and histology in the entire population (r=0.94; r=0.95, respectively) as well as with the PCDAI in CD patients (r=0.91). Conclusions: In children with active CD, CE-PEG-MRI is a very sensitive and specific test for the detection of distal ileitis and for differentiation from other inflammatory diseases of the gut. The test could also be useful for the firstline diagnostic approach in children with suspected CD. The high correlation of CE-PEG-MRI with ileal endoscopy and histology as well as with PCDAI makes this test of great interest for future studies as a tool for monitoring the clinical course and the effect of therapy in CD patients.

Inflammation is the main determinant of low bone mineral density in pediatric inflammatory bowel disease

Aims: To assess bone mineral density (BMD) in children with Crohns disease (CD) and ulcerative colitis (UC) and to investigate the role of inflammation and steroids on BMD. Methods: Lumbar spine areal BMD was measured by DXA, and volumetric BMD was then estimated (BMAD); inflammatory cytokines (TNF‐&agr;, IL‐6, IL‐10, and IL‐12) were dosed in peripheral blood; and cumulative and daily doses of steroids were calculated. Therapy with infliximab (IFX) was considered for CD patients. Results: Fifty‐six patients with IBD (35 CD, 21 UC) were studied. An inverse correlation was found between BMAD and IL‐6 in patients with UC (r = −0.65); no correlation was found between BMAD and serum levels of TNF‐&agr;, IL‐10, and IL‐12 in all patients. Disease activity indexes use inversely correlated with BMAD (r = −0.62 in patients with CD and r = −0.64 in patients with UC). Cumulative dose of corticosteroids and duration of therapy did not correlate with BMAD. The 10 patients with CD who were treated with IFX had higher BMAD (−1 ± 0.8) than those never treated with IFX (−1.8 ± 0.8). Mean Pediatric Crohns Disease Activity Index and body mass index in patients with CD (R2 = 0.48) and IL‐6 level in patients with UC (R2 = 0.43) were found to be independent and significant predictors of BMAD. Conclusions: In children with IBD, inflammation is an important determinant of bone loss, as shown by the correlation of BMAD with serum IL‐6 and with disease activity indexes as well as by the beneficial effect of IFX on bone density. Corticosteroids seem to be a less important variable in pediatric IBD‐related BMD reduction than previously believed.

Comparison of gastric electrical activity and gastric emptying in healthy and dyspeptic children.

To assess and compare gastric electrical activity and gastric emptying recorded from dyspeptic and healthy children, cutaneous electrogastrography and ultrasound examination of the gastric emptying were simultaneously performed in 52 children with nonulcer dyspepsia and 114 healthy children. Symptoms were scored from 0 (none) to 6 (severe). A higher percentage of tachygastria, a higher instability of gastric power, and a lower post/preprandial ratio were present in dyspeptic children than healthy children. As regards the ultrasound parameters, the fasting antral area and T1/2 were similar in dyspeptic children and controls. Only 32% of dyspeptic children had a normal gastric emptying time vs 66% of healthy children. Marked postprandial antral dilatation was found in the dyspeptic children, which correlated with the total symptom score. Electrogastrographic and gastric emptying parameters show specific differences in dyspeptic children with respect to controls, both fasting and after a meal. The postprandial antral distension correlates with the severity of the symptoms.

Efficacy of Adalimumab in Moderate-to-Severe Pediatric Crohn's Disease

OBJECTIVES:The use of tumor necrosis factor-alpha (TNF-α) antagonists has changed the therapeutic strategy for Crohns disease (CD). Adalimumab (ADA), a fully human anti-TNF-α monoclonal antibody, is an effective therapy for patients with CD, both naive patients and those intolerant or refractory to Infliximab (IFX), a chimeric anti-TNF-α agent. However, the use of ADA is rarely reported in pediatric CD. We performed an open prospective evaluation of short- and long-term efficacy and safety of ADA in children with moderate-to-severe CD.METHODS:A total of 23 pediatric CD patients (9 naive and 14 intolerant or unresponsive to IFX) received ADA subcutaneously as a loading schedule at weeks 0 and 2, and at every other week (eow) during a 48-week maintenance phase. Loading and maintenance doses were 160/80 and 80 mg eow in 13 cases, 120/80 and 80 mg eow in 2, and 80/40 and 40 mg eow in 8 cases. The primary efficacy outcomes were clinical remission and response at different scheduled visits along the maintenance phase. At baseline, 13 patients also received immunomodulators (IMs).RESULTS:At weeks 2, 4, 12, 24, and 48, remission rates were 36.3, 60.8, 30.5, 50, and 65.2%, respectively, whereas response rates were 87, 88, 70, 86, and 91%, respectively. Four patients at week 24 and 2 at week 48 received IMs; the mean daily corticosteroid dose, disease activity index, C-reactive protein level, and erythrocyte sedimentation rate decreased significantly throughout the trial. No serious adverse events were recorded.CONCLUSIONS:ADA can be an effective and safe biological agent for inducing and maintaining remission in children with moderate-to-severe CD, even in those with previous IFX therapy.

Evolution of Gastric Electrical Features and Gastric Emptying in Children with Duchenne and Becker Muscular Dystrophy

OBJECTIVES:Although muscular dystrophy (MD) affects primarily striated muscles, smooth muscle cells of the gastrointestinal tract may also be involved. We recorded gastric electrical activity and gastric emptying time (GET) in children with MD at initial presentation and at 3-yr follow-up in order to detect gastric motor abnormalities and study their evolution along the clinical course.METHODS:Twenty children with MD (median age: 4.6 yr; range age: 3–7 yr) were investigated by means of ultrasonography, for measuring GET, and by electrogastrography (EGG); 70 children served as controls.RESULTS:Ten patients had Duchenne muscular dystrophy (DMD) and 10 Becker muscular dystrophy (BMD). GET was significantly more delayed in MD patients (DMD, median: 195 min; range 150–260 min; BMD, median: 197 min; range: 150–250 min) than in controls (median: 150 min; 110–180 min; p < 0.05); it markedly worsened at the follow-up in DMD (median: 270 min; range 170–310 min; p < 0.001 vs controls) but not in BMD patients (median: 205 min; 155–275 min; p < 0.05 vs DMD). Baseline EGG showed a significantly lower prevalence of normal rhythm and significantly higher prevalence of dysrhythmias in both groups of patients as compared to controls (% of normal rhythm: DMD 66.7 ± 8.2, BMB 67.2 ± 11.5, controls 85.3 ± 7.2, p < 0.001; % of tachygastria: DMD 28.4 ± 8.0, BMB 29.8 ± 12.3, controls 10.6 ± 5.1, p < 0.001; % of dominant frequency instability coefficient: DMD 36.1 ± 6.0, BMB 33.2 ± 2.9, controls 17.9 ± 7.1, p < 0.001); furthermore, no difference in fed-to-fasting ratio of the dominant EGG power was found between the two groups and controls (DMD 2.84 ± 1.27, BMB 2.82 ± 0.98, controls 3.04 ± 0.85, ns). However, at the follow-up no significant change in the prevalence of normal rhythm and dysrhythmias occurred in both groups (ns vs baseline values), whereas only DMD patients showed a marked reduction in fed-to-fasting power ratio (0.78 ± 0.59; p < 0.001 vs controls and BMD; p < 0.05 vs baseline), which correlated with the progressive neuromuscular weakness occurring in DMD subjects (r, 0.75; p < 0.001).CONCLUSIONS:In children with MD, there is an early abnormality in gastric motility that is due to deranged regulatory mechanisms, whereas contractile activity of smooth muscle cells seems to be preserved. At the follow-up, DMD patients exhibited a progressive failure in neuromuscular function, which was accompanied by a gastric motility derangement with worsening in GET and in EGG features suggesting an altered function of gastric smooth muscle cells.

High-resolution colonic manometry accurately predicts colonic neuromuscular pathological phenotype in pediatric slow transit constipation.

Background  Severe pediatric slow transit constipation (STC) is commonly due to intrinsic colonic neuromuscular disease. We sought to correlate neuromuscular histological phenotypes in pediatric STC with colonic manometric phenotypes using high‐resolution manometry (HRM). We tested the hypothesis that failure of motor quiescence (FQ) between bisacodyl‐induced high amplitude propagating sequences (HAPSs) might predict neuromuscular pathology.

Effects of Omeprazole on Mechanisms of Gastroesophageal Reflux in Childhood

Prolonged recordings of esophageal motility haveshown that dynamic changes of lower esophageal sphincter(LES) pressure such as transient LES relaxation and LESpressure drifts are the most common mechanisms underlying gastroesophageal reflux (GER). Thecoexistence of a delayed gastric emptying has also beenreported in a high proportion of patients with refluxdisease. However, not much information is available on the effects of antireflux therapy on thepathogenetic mechanisms of GER. The purpose of thisstudy was to determine in a group of children withsevere reflux disease the effect of omeprazole therapy on motor changes of LES underlying GER as wellas on gastric emptying time. Twenty-two children (medianage: 6.6 years) with GER disease, refractory to combinedranitidine and cisapride administration, entered into an eight-week omeprazole course.Ten subjects with moderate GER disease served ascontrols (median age: 6.0 years). Before and afteromeprazole administration, the following variables were assessed: esophagitis grading, fasting and fedsimultaneous prolonged recording of distal esophagealsphincter pressure (with a sleeve catheter) andintraesophageal pH, LES and esophageal peristalsisamplitude, and gastric emptying time of a mixedsolid-liquid meal (measured with gastric ultrasound). Ascompared to controls, patients showed a higher rate oftransient LES relaxation and LES pressure drift (P <0.01), a reduced amplitude of basal sphincter pressure(P < 0.01) and peristalsis (P < 0.05), and a moreprolonged gastric emptying time (P < 0.05). Afterending omeprazole, there was no significant change inany of the motor abnormalities of the esophagus and ingastric emptying time despite a marked improvement ofsymptoms and esophagitis in all patients. Sixteenpatients were symptomatic when reevaluated on a clinical basis two months after ending therapy. Weconclude that in children with severe GER disease, anabnormally high rate of both transient LES relaxationand LES pressure drift and slow gastric emptying are not affected by omperazole treatment, eventhough esophageal mucosal damage is markedly improved orcured. These abnormalities represent a primary motordisorder and can be implicated in the refractoriness of reflux disease.

Mast cell-nerve interactions in children with functional dyspepsia.

Background and Aims: Functional dyspepsia in childhood is commonly triggered by food allergen in sensitised individuals. We investigated the topography of eosinophils and mast cells in gastric antral lamina propria, the interaction of mast cell products with mucosal nerve fibres, and changes in gastric antral muscle slow wave activity in children with atopy and non–atopy-related functional dyspepsia. Patients and Methods: Open label study of gastric mucosal cows milk challenge in 10 atopic and 6 nonatopic children (ages 2–12 years) investigated consecutively with gastroscopy for functional dyspepsia. Simultaneous surface electrogastrography and milk challenge were undertaken and laser scanning fluorescence microscopy used to examine the association of mast cell tryptase with mucosal nerves in the gastric mucosa before and after challenge. Results: Eosinophils and mast cells within the lamina propria were increased in number in children with atopic functional dyspepsia and degranulated rapidly after cows milk challenge in the atopic group. For degranulating eosinophils, median = 13.0% (interquartile range = 3.7–31.0) premilk versus 32.0% (12.0–42.0) after milk biopsies (P < 0.05); for degranulating mast cells, 5.35% (2.7–10.9) premilk biopsies versus 18.75% (12.9–22.1) after milk biopsies (P < 0.05). No such differences were seen in nonatopic patients. Mast cells were closely associated with mucosal nerve fibres and released tryptase, which colocalised with proteinase-activated receptors on mucosal nerve fibres. The gastric antral slow wave became abnormal within 2 minutes of antigen challenge in atopics with an increase in dominant frequency instability coefficient (P < 0.005), decrease in 3 cycles per minute myoelectrical activity (P < 0.01), and increase in bradygastria (P < 0.01). Conclusions: Early-onset neuroimmune interactions induced by cows milk in the gastric mucosa of atopic children are associated with rapid disturbance of gastric myoelectrical activity and dyspeptic symptoms.

Neuroimmune Interaction and Anorectal Motility in Children With Food Allergy-Related Chronic Constipation

OBJECTIVES:Food allergy is thought to trigger functional constipation in children but the underlying mechanisms are still unknown. Mast cells (MCs) and their relationship with nerve fibers (NFs) in the rectal mucosa, as well as anorectal motility, were studied in children with refractory chronic constipation before and after an elimination diet for cows milk, egg, and soy proteins.METHODS:Thirty-three children (range: 1–10.8 years) underwent anorectal manometry and suction rectal biopsy before and after 8 weeks of oligoantigenic diet. MCs and NFs were identified immunohistochemically. Quantification of MCs (%MC/area) and MCs within 10 μm of NFs (%MC-NF/area) was performed by computer-assisted analysis.RESULTS:Eighteen children responded to the diet (R-group) and fifteen did not (the NR-group). At baseline there was a significant difference in anal resting pressure (ARP; mm Hg), percentage of relaxation (%R), and residual pressure (RP; mm Hg) of anal canal during rectal distension between the R-group (66±4.1, 84.3±2.8, 10.4±2.3, respectively) and the NR-group (49±5, 92.2±1.7, 4.8±1.7, respectively; P<0.05). After the diet, significant changes in ARP, RP, and %R were observed only in the R-group (44±3.7, 93.7±1.5, 3.8±1.2, respectively; P<0.05). At baseline, the R-group showed an increase in %MC/area (8.3±0.7) and %MC-NF/area (5.2±2.6) with respect to the NR-group (5.1±0.5 and 2.3±0.4, respectively; P<0.05). After the diet, only the R-group showed a significant reduction of %MC/area and %MC-NF/area (4.4±0.5 and 2.2±0.4, respectively; P<0.001). Both ARP and RP significantly correlated with %MC/area and %MC-NF/area; %R showed a significant inverse correlation with both %MC/area and %MC-NF/area.CONCLUSIONS:In children with food allergy-related chronic constipation, an increase in both rectal MC density and spatial interactions between MCs and NFs correlates with anal motor abnormalities. These variables are significantly affected by the diet.