Laura de Magistris

Effects of bombesin on gastrin and gastric acid secretion in patients with duodenal ulcer

The effect of bombesin, a possible neurotransmitter of gastrin release, upon gastrin and gastric acid secretion was investigated in 25 patients with duodenal ulcer and in 16 normal subjects. In patients with duodenal ulcer bombesin (10 ng/kg/min) produced an increase in plasma gastrin output (median 22·4 (range 7·5-75·8) pmol/l/min) similar to that obtained in normal subjects (median 24·4 (range 5·8-56·5) pmol/l/min), whereas gastrin stimulated by a meal was significantly higher in the group of patients with duodenal ulcer (median 20·7 (range 9·2-42·9) vs 16·2 (range 3·4-22·2) p<0·05). Peak acid output induced by bombesin was significantly higher in patients with duodenal ulcer than in normal subjects (median 24·4 (range 9·0-63·8) vs 14·0 (range 3·0-24·8) mmol/h, p<0·05) despite identical gastrin outputs. The ratio (%) obtained by dividing the acid secretory response to bombesin by the response to pentagastrin, however, was similar in both normal subjects and patients with duodenal ulcer (median 55 (range 20-116) vs 58 (range 31-95) respectively). The difference between the gastrin response to food and bombesin could be explained by the fact that bombesin releases gastrin directly, whereas a protein meal involves several mechanisms (neural, peptidergic, paracrine, endocrine), either stimulatory or inhibitory. The above results indicate that a higher concentration in antral and/or duodenal gastrin is unlikely to be present in patients with duodenal ulcer. An increased parietal cell mass could explain the higher gastric acid response after bombesin infusion in our group of patients with duodenal ulcer.

Effect of bombesin-stimulated gastrin on gastric acid secretion in man

The effect of bombesin on gastrin release and gastric acid secretion was investigated in 10 healthy volunteers. Bombesin (0.6 μg · Kg−1 · hr−1) produced a significantly higher (p < 0.001) increase in plasma gastrin levels (86.7 11.1 pmo/1 than after a protein meal (39.6 ± 5.6 pmol1/1). The gastric acid secretory response to bombesin (12.1 ± 2.9 mEq · hr−1) was however significantly lower (p < 0.005) than the maximal response produced by pentagostrin (20.9 ± 3.5 mEq · hr−1) at the dose of 6 μg · Kg−1. Atropine did not modify gastrin release induced by bombesin but significantly reduced gastric acid secretion (p < 0.01). From the data presented it may be hypothesized that less biologically active forms of gastrin and/or other peptides inhibiting the gastrin effect upon gastric acid secretion may be released by bombesin.

Differential stimulation of pancreatic-polypeptide and gastrin secretion by bombesin in man.

Abstract Bombesin, besides many other actions on the mammalian gastroentero-pancreatic tract, strongly stimulates the release of pancreatic-polypeptide (PP) in dogs. In 8 healthy human volunteers (5 males, 3 females), the PP response during bombesin infusion was low (25.7 ± 6.3 peak vs. 5.0 ± 2.0 basal pmol/1) compared to the effect of a protein meal (144.1 ± 13.4 pmol/1) or to the gastrin response to the same dose of the amphibian polypeptide (140.0 ± 23.6 pmol/1 eq SHG 17 I). The response pattern of PP and gastrin was different as PP concentrations peaked 10 min after cessation of bombesin infusion (32.0 ± 4.9 pmol/1) when gastrin concentrations already were down to one third of the maximal response. Atropine inhibited the PP response to bombesin but did not abolish it completely. It is concluded that in man, the total effect of bombesin on PP secretion is minor compared both to the effect of the peptide on gastrin secretion in man and to the effect of bombesin in dogs. It is suggested that bombesin might have a dual, inhibitory-stimulatory, effect on PP secretion in man.

Effect of Bombesin on Lower Esophageal Sphincter Pressure in Humans

Intravenous infusion of bombesin in humans results in increased serum gastrin levels and increased lower esophageal sphincter pressure. To differentiate a gastrin- from a nongastrin-mediated mechanism, the effect of intravenous bombesin infusion on lower esophageal sphincter pressure was studied in 5 healthy subjects and in 5 antrectomized patients. Lower esophageal sphincter pressure was recorded by three continuously perfused catheters with side-openings located 5 mm apart. Blood samples were taken at regular intervals during the study periods to assay gastrin and pancreatic polypeptide. Manometric tracings and blood samples were coded and evaluated blindly. Lower esophageal sphincter pressure increased during bombesin infusion both in normal and antrectomized subjects. The increase had a delayed onset and persisted after discontinuation of bombesin. No correlation was found between lower esophageal sphincter pressure and serum gastrin or pancreatic polypeptide values. These data indicate that the effect of bombesin on lower esophageal sphincter pressure is not gastrin or pancreatic polypeptide mediated.

167 The Microbiome Signature of Autistic Children Is Characterized by Decreased Diversity and Dysbiosis

Background: Autism Spectrum Disorders (ASDs) are complex neuro-developmental disorders characterized by cognitive defects, social interaction skills impairments and communication, language and behavioral problems. A strong correlation between autism severity and GI symptoms, alterations of intestinal permeability (IP), presence of inflammation and intestinal dysbiosis has been described. It has recently been proposed that alterations of the intestinal microbiota could contribute to the development of ASDs. Recent studies demonstrated that autistic children with gastrointestinal symptoms show major fecal microbiota alterations. In this study we aimed to study the fecal candida and bacterial microbiota, their correlation to intestinal permeability, in autistic children compared to normal developing children, in order to provide rational basis to a possible specific therapeutic intervention in restoring gut microflora in ASDs. Material and Methods: We collected stool samples from 47 subjects with ASDs (40 boys and 7 girls, mean age 6.0 ± 2.8 yr), and 33 healthy children matched controls (24 boys and 9 girls, mean age 7.3 ± 3.1 yr). Search for Candida culture and biochemical identification of the colonies were performed by Sabouraud Dextrose Agar + Chloramphenicol + Gentamicin, Oxoid Products Microbiology and analized by ID 32 C (bioMerieux) system. In a subgroup of 12 ASDs subjects (8 boys and 4 girls, mean age 6.8 ± 2.9 ), and 16 healthy children matched controls (8 boys and 8 girls, mean age 7.3 ± 3.1 yr), total microbial DNA was extracted and 16S variable region V4 amplified by PCR. The results were analyzed by QIIME software. Intestinal Permeability (IP) was assessed with the lactulose/mannitol (LA/MA) test. Results: Compared to HC, ASDs samples presented an increased number of Proteobacteria combined with a reduction of Bacteroidetes and Actinobacteria. Microbial diversity was reduced in ASDs children, albeit they were more phylogenetically different. Interestingly, β-diversity analysis showed 2 distinct clouds in ASDs children, one dominated by E. Coli and the other with no clear domination. Candida spp was detected in the stools of 15 ASD children (31.9%) compared to controls (6.1%). Interestingly in ASDs, C. albicans was most frequently identified (9 out of 15 cases). Finally, IP resulted altered in 42.4% of ASDs compared to 22.7% of controls (p < 0.05). No correlation was detected between altered IP and either microbiome composition or candidosis. Conclusions: In this proof-of-concept study we establish that ASD children have a specific microbiome signature characterized by decreased diversity and quantitative representation of some specific phyla. Candida infestation, particularly C. albicans was more frequently detected in ASD children than controls.

251 CXCR3 Splice Variants in Celiac Disease and Non-Celiac Gluten Sensitivity

Intestinal villi provide an enormous surface area for nutrient absorption. Significant loss of intestinal surface area can compromise intestinal function, causing intestinal failure. Though short-term treatments for this life-threatening condition are available, all patients need lifelong monitoring for growth and nutritional status, and would benefit from treatments that can directly increase intestinal surface area. In mice, a large increase in surface area occurs with villus development, which begins at embryonic day (E)14.5, when the thick pseudostratified epithelium with a flat luminal surface is converted to a columnar epithelium covering a field of emerging villi. Though it has long been thought that epithelial remodeling occurs by formation and fusion of secondary lumina, recent work in our laboratory showed that secondary lumina do not exist (Grosse et al., Development 138:4423, 2011). Seeking an alternative mechanism for luminal expansion, we found a unique type of cell division that is triggered specifically at E14.5, which we have named an e-division (lumen extending division). We propose that in an e-division, new apical surface is deposited at the cytokinetic plane such that the two daughter cells segregate onto adjacent villi. The e-division is distinct from cell divisions occurring before E14.5, which we have named g-divisions (girth building divisions); g-divisions do not involve deposition of new apical surface between daughter cells. Our data (lineage tracing, 3D reconstruction, and SEM) suggest that in mice deficient in the apical surface protein Ezrin, e-divisions fail stochastically, resulting in fused villi. We are modeling e-divisions in vitro using MDCK and Caco2 cell lines, which form luminal surfaces during the first cell division when plated in a 3D matrix. Using RNA interference, we have found that reducing Ezrin expression compromises lumen formation in our 3D cyst assay, providing a mechanistic explanation for the presence of fused villi in vivo. Further understanding of the process of villus development will improve in vitro bioengineering of intestinal surface, potentially yielding novel therapies for those with intestinal failure.

Su2077 Antibodies Against Alfa Gliadin (AGA) and Deamidated Gliadin Peptides (DGP) in Patients With Autistic Spectrum Disorder (ASD)

Background: Autism and autism spectrum disorders (ASDs) are enigmatic conditions that have their origins in the interaction between genes and environmental factors. Several studies suggest that increased gut-blood-brain-barrier permeability might be involved in the pathogenesis of these conditions. Recently, we have reported an increased intestinal permeability (IPT) “leaky gut” in a large percentage of not celiac autistic subjects that seemed be influenced by gluten-free diet. We can hypothesize that autistic patients(pts) are gluten sensitive, as well as it happens in other recently described conditions such as individuals with Schizophrenia. Aim: it was to evaluate antibody prevalence to gliadin (AGA), transglutaminase (tTG), deamidated gliadin peptides (DPG), endomysium (EMA) in a group of autistic pts with gastro-intestinal symptoms (GI) and/or altered IPT being on regular alimentary regimen (RAR) or on gluten-casein free diet (GCFD). Patients and methods: in 70 ASD children (54 RAR, 16 GFD) were performed serologic test combination representing Celiac Disease (CD): total serum IgA (sIgA), AGA, DGP, tTG, EMA IgA-IgG by ELISA and HLA haplotype by Eurospital Eu-DQ kit. Results: All pts had normal sIgA values and were negative for tTG, EMA (IgA and IgG); a low number of pts, 1/69 (1.40%) showed positive AGA-IgA in contrast to 22/70 (31.40%) with positive AGA IgG; out of 5 (7.10%) of these pts had also positive DGP IgG. Moreover, of the 22 AGA IgG positive pts, 50% (11) were HLA negative. Among the RAR pts, we found 38.90%( 21/54) AGA IgG positive, compared to only 6.30% (1/16) that were on GCFD. Interestingly, a large percentage of pts (90.5%) on RAR have impaired intestinal barrier function, while implementation of a GCFD normalizes intestinal barrier function in approximately 1/3 ( 38.7%) of ASD pts. Conclusions: Our preliminary results suggest that a sub-group of autistic children could have Gluten Sensitivity. The findings may have potential implications for the treatment of these subjects given that a GFD could contribute to the improvement of their symptoms.

65 Mucosal Duodenal Tissue From Gluten-Sensitive Patients Do Not Have Increased Expression of IgA B Cell Switch Markers

(heterozygous state,10%), R202Q (heterozygous state, 3%) and R202Q + M694V mutations (3%). GI motility was assessed in the asymptomatic phase by functional ultrasonography (changes of gastric antral areas and gallbladder volumes; 5.0 MHz ClarUs©, Telemed device) and H2-breath test (orocecal transit time by Lactofan®, FAN-GmbH, DE and Italchimici, Italy). Measurements were taken at 5-15 min intervals in the fasting state and during 270 min postprandially after a 200ml liquid meal formula (Nutridrink®, Nutricia added with 10g lactulose). A group of 142 agesexBMI-matched healthy subjects served as control (M:F=67:75, age 38±1 yrs). Results. Acute attacks (1 day mean duration), had a frequency of <1 (48%), 2 (22%) and ≥3 (13%) episodes/mo. Symptoms included abdominal pain and fever (44%), joint pain (22%), fever alone (9%), fatigue (4%), erysipelas-like erythema (4%) or none (17%). Although the mean age at symptom onset was 19.2±8.4 yrs, FMF was only diagnosed after 15.4±9.7 yrs. Compared to control, FMF patients had comparable fasting antral areas (3.3±0.2 vs. 3.2±0.1 cm2), but increased max postprandial area (14.1±0.4 vs. 11.6±0.2 cm2, P<0.000001), residual postprandial area (4.3±0.2 vs. 3.5±0.1 cm2, P<0.001) and longer half emptying time (43.2±1.2 vs. 26.6±0.5 min, P<0.000001). Gallbladder vol. in FMF and control was comparable during fasting (19.8±2.1 vs. 22.4±0.5 ml) and postprandially (residual 5.4±0.4 vs. 5.5±0.2 ml), with a trend of increased percent residual volume (28.9±1.6 FMF vs. 24.8±0.7 % in controls, P=0.059). Gallbladder emptying time was comparable in FMF and control (23.2±1.7 FMF vs. 21.0±0.5 min). OCTT was longer in FMF (132.3±10.5 vs. 99.5±1.6 min, P<0.000001). All FMF patients responded to colchicine therapy 1 mg/day p.o. Conclusions. In a novel cluster of FMF patients, the final diagnosis of FMF is consistently delayed. Patients with FMF exhibit impairedmotorfunction in the GI tract but not in the gallbladder. Our study of GI motility provides additional clues on the natural history of this rare disorder before and after therapy.

Intestinal permeability is deveeased in anorexia nervosa

Malnutrition and absence of exogenous luminal nutrients in the gastrointestinal tract affect intestinal permeability (IP) leading to an increased penetration of substances that passively cross intestinal epithelium via intercellular pathways. We hypothesised that an increase in IP could occur in patients with anorexia nervosa because of their prolonged fasting and chronic malnutrition. Therefore, we assessed IP in 14 drug-free anorexic women and 19 drug-free agematched healthy women by means of the lactulose/mannitol (LA/MA) test. To this purpose, after an overnight fast, subjects ingested an oral solution containing 5 g lactulose and 2 g mannitol in 100 ml water. Urine specimens were collected immediately before and 30, 60, 120, 180, 240 and 300 min after the ingestion of the sugar solution. Urinary lactulose and mannitol were determined by high-performance anion exchange chromatography coupled with pulsed amperometric detection. We found that IP, as expressed by the 5-h LA/MA excretion ratio, was significantly decreased in anorexic women because of a lower urinary recovery of lactulose. Moreover, in patients, the time course of lactulose excretion significantly differs from healthy controls. These results do not confirm our hypothesis of increased IP in anorexia nervosa. Since IP reflects the anatomo-functional status of intestinal mucosa, the present findings support the idea that changes in the anatomo-physiology of intestinal mucosa occur in anorexia nervosa. Molecular Psychiatry (2004) 9, 76‐80. doi:10.1038/sj.mp.4001374