Clinical significance of small bowel manometry patterns suggestive of intestinal obstruction.

INTRODUCTION: Minute rhythm and prolonged simultaneous contractions are patterns of postprandial small bowel contractile activity that historically have been considered as suggestive of mechanical intestinal obstruction; however, these patterns have been also encountered in patients with motility-like symptoms in the absence of bowel obstruction. The objective of this study was to determine the current diagnostic outcome of patients with these intestinal manometry patterns. METHODS: Retrospective study of patients with chronic digestive symptoms evaluated by intestinal manometry at our center between 2010 and 2018. RESULTS: The minute rhythm (MRP) or prolonged simultaneous contractions (PSC) postprandial patterns were detected in 61 of 488 patients (55 MRP and 6 PSC). Clinical work-up detected a previously non-diagnosed partial mechanical obstruction of the distal intestine in 10 (16%) and a systemic disorder causing intestinal neuropathy in 32 (53%). In the remaining 19 patients (31%, all with MRP), the origin of the contractile pattern was undetermined, but in 16, substantial fecal retention was detected within 7 days of the manometric procedure by abdominal imaging, and in 6 of them colonic cleansing completely normalized intestinal motility on a second manometry performed within 39 ± 30 days. CONCLUSION AND INFERENCE: Currently, the most frequent origin of MRP and PSC encountered on small bowel manometry is intestinal neuropathy, while a previously undetected mechanical obstruction is rare. Still, in a substantial proportion of patients, no underlying disease can be identified, and in them, colonic fecal retention might play a role, because in a subgroup of these patients, manometry normalized after colonic cleansing. Hence, colonic preparation may be considered prior to intestinal manometry.

Functional neuromuscular impairment in severe intestinal dysmotility.

BACKGROUND: Chronic intestinal pseudo-obstruction (CIPO) and enteric dysmotility (ED) are severe intestinal motility disorders usually associated with underlying neuromuscular abnormalities. OBJECTIVE: To evaluate the in vitro neuromuscular function of patients with severe intestinal motility disorders. METHODS: Full-thickness intestinal biopsies (16 jejunum and 3 ileum) obtained from patients with CIPO (n = 10) and ED (n = 9) were studied using muscle bath and microelectrode techniques. Control samples (n = 6 ileum and n = 6 jejunum) were used to establish the range of normality. KEY RESULTS: Fourteen parameters were defined to assess muscle contractility and nerve-muscle interaction: five to evaluate smooth muscle and interstitial cells of Cajal (ICC) and nine to evaluate inhibitory neuromuscular transmission. For each sample, a parameter was scored 0 if the value was inside the normal range or a value of 1 if it was outside. Patients' samples (CIPO/ED) had more abnormal parameters than controls (P < 0.001 for both jejunum and ileum). Functional abnormalities were found to be heterogeneous. The most prevalent abnormality was a decreased purinergic neuromuscular transmission, which was detected in 43.8% of jejunal samples. CONCLUSIONS AND INFERENCES: Abnormalities of neuromuscular intestinal function are detected in vitro in severe intestinal dysmotility. However, consistent with the heterogeneity of the disease pathophysiology, functional impairment cannot be attributed to a single mechanism. Specifically, defects of purinergic neuromuscular transmission may have an important role in motility disorders of the gastrointestinal tract.

Assessment of rectocolonic morphology and function in patients with Chagas disease in Barcelona (Spain).

The aim of this study was to determine the relationship between colonic symptoms, radiological abnormalities, and anorectal dysfunction in patients with Chagas disease. We performed a cross-sectional study of untreated patients diagnosed with Chagas disease. All patients were evaluated clinically (by a questionnaire for colonic symptoms based on Rome III criteria) and underwent a barium enema and anorectal manometry. A control group of patients with functional constipation and without Chagas disease was included in the study. Overall, 69 patients were included in the study: 42 patients were asymptomatic and 27 patients had abdominal symptoms according to Rome III criteria. Anorectal manometry showed a higher proportion of abnormalities in symptomatic patients than in asymptomatic ones (73% versus 21%, respectively; P < 0.0001). Megarectum was detected in a similar proportion in the different subgroups regardless of the presence of symptoms or abnormalities in anorectal functions. Among non-Chagas disease patients with functional constipation, 90% had an abnormal anorectal manometry study. Patients with Chagas disease present a high proportion of constipation with dyssynergic defecation in anorectal manometry but a low prevalence of impaired rectoanal inhibitory reflex, although these abnormalities may be nonspecific for Chagas disease. The presence of megarectum is a nonspecific finding.

Vitamin E and vitamin E acetate absorption from self-assembly systems under pancreas insufficiency conditions.

We determined the bioavailability of vitamin E from self-assembly structures in patients with diagnosed chronic pancreas insufficiency. Vitamin E solubilized in dispersed inverted bicontinuous cubic phase and in micellar formulation was delivered directly to the small intestine by tube-feeding. A cross-over study with randomization of 6 subjects and 2 treatments including a combined dose of 18 mg (27 IU) of vitamin E (RRR-[5,7-methyl-((2)H6)]-α-tocopherol) and 27 mg (27 IU) vitamin E acetate (RRR-[5-methyl-(2)H3]-α-tocopheryl acetate) was applied over a time period of 1 h. Plasma samples were collected for 56 h and analyzed by liquid chromatography-mass spectrometry. Appearance of labeled tocopherols originating from the treatment started at 25 h and reached Cmax (0.6-4.6 µM depending on subject) in the 7-9 h window. From the Tmax onwards, both forms of tocopherols diminished slowly to 30-50% of their maxima within 56 h. Strong inter-individual variation was observed in the plasma appearance curves (relative standard deviation varied between 38-45%). No significant discrimination was found between the absorption of free or acetylated forms of deuterated α-tocopherol confirming that application of acetylated α-tocopherol provides the same bioavailability as free α-tocopherol. This observation is valid in both dispersed inverted bicontinuous cubic phase and micellar formulations. Furthermore, since the area-under-the-curve values from cubic phase and from micellar formulations are similar, the cubic phase formulation could represent an alternative delivery system for lipophilic micronutrients in conditions or studies where polysorbate-based micelles cannot be generated.

Chronic psychosocial stress induces reversible mitochondrial damage and corticotropin-releasing factor receptor type-1 upregulation in the rat intestine and IBS-like gut dysfunction.

The association between psychological and environmental stress with functional gastrointestinal disorders, especially irritable bowel syndrome (IBS), is well established. However, the underlying pathogenic mechanisms remain unknown. We aimed to probe chronic psychosocial stress as a primary inducer of intestinal dysfunction and investigate corticotropin-releasing factor (CRF) signaling and mitochondrial damage as key contributors to the stress-mediated effects. Wistar-Kyoto rats were submitted to crowding stress (CS; 8 rats/cage) or sham-crowding stress (SC; 2 rats/cage) for up to 15 consecutive days. Hypothalamic-pituitary-adrenal (HPA) axis activity was evaluated. Intestinal tissues were obtained 1h, 1, 7, or 30 days after stress exposure, to assess neutrophil infiltration, epithelial ion transport, mitochondrial function, and CRF receptors expression. Colonic response to CRF (10 µg/kg i.p.) and hyperalgesia were evaluated after ending stress exposure. Chronic psychosocial stress activated HPA axis and induced reversible intestinal mucosal inflammation. Epithelial permeability and conductance were increased in CS rats, effect that lasted for up to 7 days after stress cessation. Visceral hypersensitivity persisted for up to 30 days post stress. Abnormal colonic response to exogenous CRF lasted for up to 7 days after stress. Mitochondrial activity was disturbed throughout the intestine, although mitochondrial response to CRF was preserved. Colonic expression of CRF receptor type-1 was increased in CS rats, and negatively correlated with body weight gain. In conclusion, chronic psychosocial stress triggers reversible inflammation, persistent epithelial dysfunction, and colonic hyperalgesia. These findings support crowding stress as a suitable animal model to unravel the complex pathophysiology underlying to common human intestinal stress-related disorders, such as IBS.

Validation of the Spanish version of a questionnaire to measure quality of care through the eyes of patients with inflammatory bowel disease (QUOTE-IBD).

BACKGROUND: Crohn's disease (CD) and ulcerative colitis (UC) are chronic immunoinflammatory diseases that place a considerable burden on patients, their families, and society. Quality of care plays an important role for patients. A questionnaire to measure quality of care through the eyes of patients with inflammatory bowel disease (QUOTE-IBD) has been designed and validated specifically for the English language and culture. The objective was to translate the QUOTE-IBD into Spanish and to determine its validity in patients with IBD. METHODS: This is a prospective study in 2 phases: first, translation and validation of the Spanish QUOTE-IBD. Translation was based on the validated QUOTE-IBD. Second, once the complete translation was finished, comprehension of the items was assessed with a specific questionnaire in a reduced number of patients. Criterion validity was assessed with the Pearson's correlation coefficient between scores of the QUOTE-IBD and visual analog scales (VAS). In order to analyze the reproducibility of the Spanish QUOTE-IBD, the questionnaire was completed by stable patients twice, with a span of time of at least 4 weeks. RESULTS: A total of 103 patients (CD: 61, UC: 42) were included in the study. Pearson's correlation coefficient between total care Spanish QUOTE-IBD and VAS of health care items was 0.34 (P < 0.001). Correlations among all 6 care dimensions score of Spanish QUOTE-IBD and VAS were statistically significant (P < 0.01). Results of first and second administration of total care and dimensional care scores of Spanish QUOTE-IBD in 46 stable patients were not different. CONCLUSIONS: The Spanish QUOTE-IBD has proved to be a valid instrument to measure the quality of health care for patients with CD and UC.

Metabotyping of biofluids reveals stress-based differences in gut permeability in healthy individuals.

Life stress promotes gut dysfunction, but underlying biochemical events are not well-understood. In the present study, we describe the metabolic events associated with background stress and its potential influence on the response to novel incoming stress stimulus in healthy subjects. A 15 min cold pain test was carried out in healthy men and women stratified according to low (LS; n = 21) and moderate background stress (MS; n = 9) during jejunal segmental perfusion. Cold pain induced a stronger psychological response in MS compared to LS subjects, but similar increases in heart rate and blood pressure. Urine and plasma were analyzed using 1H NMR-based metabonomics. Basal stress levels were imprinted in the metabolic profiles indicating different energy and lipid homeostasis. Cold pain increased gut permeability, as determined by mannitol and xylose levels, the response being greater in LS subjects. Moreover, the rate of plasma clearance of mannitol and xylose was dependent on background stress level and gender. In addition, cold pain modulated the levels of circulating ketone bodies, Krebs's cycle intermediates, glucose, and the glucogenic alanine and lactate, which brings further evidence of an alteration of energy homeostasis. Therefore, unravelling life stress with metabonomics may provide a system biology basis for the clinical management and therapeutic surveillance of gut health and disorders.

Abdominal accommodation: a coordinated adaptation of the abdominal wall to its content.

BACKGROUND AND AIM: We previously showed that colonic gas infusion increases the girth and modifies the muscular activity of the anterior abdominal wall. We hypothesized that abdominal accommodation to volume loads is an active process instrumented by the coordinated activity of the anterior wall and the diaphragm. METHODS: To increase intraabdominal volume in healthy subjects, a gas was infused into the colon (1.44 L in 1 h) while measuring girth (by tape measure) and electromyography (EMG) activity of the anterior wall (via four pairs of surface electrodes) and the diaphragm (via six ring electrodes over an esophageal tube in the hiatus). After preliminary feasibility studies (N = 12), postural activity (N = 6) and responses to colonic gas loads, both with the trunk erect (N = 8) and in supine position (N = 8), were studied. A morphometric analysis was performed by computed tomography, image analysis (N = 8). RESULTS: In the erect position, anterior wall tone was higher and diaphragmatic tone was lower than in the supine position. With the trunk erect, gas infusion induced diaphragmatic relaxation (by 21 +/- 3%; P < 0.05) and anterior wall contraction (16 +/- 4% EMG increment; P < 0.05). By contrast, in the supine position, it induced diaphragmatic contraction (15 +/- 6%, P < 0.05), while the anterior wall, in the absence of postural tone, showed no change (3 +/- 2%, NS). Gas infusion was associated with girth increase (7.3 +/- 1.0 mm with the trunk erect and 8.6 +/- 1.4 mm in the supine position) and diaphragmatic ascent (17.6 +/- 5.2 mm; P < 0.05). CONCLUSION: The degree of abdominal distension produced by intraabdominal volume increments results from posture-related abdomino-phrenic muscular responses.

The gut microbiota predispose to the pathophysiology of acute postradiotherapy diarrhea.

INTRODUCTION: Severe diarrhea may complicate pelvic radiotherapy and force interruption of treatment. As there is no current clinical or experimental information on the role of the gut microbiota in this pathogenesis, we conducted a pilot observational study on the fecal microbiota in patients receiving pelvic radiotherapy. METHODS: The study involved 10 patients who underwent 5 wk of radiotherapy for abdominal tumors and 5 controls. Four fecal samples were collected from each individual: before, during, at the end, and 2 wk after treatment. Following the amplification of the bacterial 16S rRNA gene from the samples, DNA fingerprinting and cloning-sequencing techniques were used to determine their microbial profile and composition, respectively. RESULTS: Six patients suffered acute postradiotherapy diarrhea and 4 did not. In patients without diarrhea, as well as in healthy volunteers, microbial diversity was stable over a period of 7 wk. However, patients exhibiting diarrhea showed a progressive modification in their microbial diversity. A radical drop in similarity index was observed at the end (P= 0.026) and still 2 wk after radiotherapy (P= 0.014). Interestingly, cluster analysis of the microbial profile in the first sample (S1) (collected before radiotherapy) displayed a dendogram where patients that presented diarrhea clustered separately from those that did not develop diarrhea after radiotherapy. Moreover, sequence analysis of dominant bacteria in the S1 sample confirmed differences between the diarrhea and nondiarrhea groups. DISCUSSION: In this set of patients, susceptibility or protection against diarrhea after radiotherapy could be linked to different initial microbial colonization.

Maladaptive intestinal epithelial responses to life stress may predispose healthy women to gut mucosal inflammation.

BACKGROUND & AIMS: Irritable bowel syndrome (IBS), a highly prevalent disorder among women, has been associated with life stress, but the peripheral mechanisms involved remain largely unexplored. METHODS: A 20-cm jejunal segment perfusion was performed in 2 groups of young healthy women, equilibrated by menstrual phase, experiencing either low (LS; n = 13) or moderate background stress (MS; n = 11). Intestinal effluents were collected every 15 minutes, for 30 minutes under basal conditions, and for 1 hour after cold pain stress. Cardiovascular and psychological response, changes in circulating stress and gonadal hormones, and epithelial function (net water flux, albumin output and luminal release of tryptase and alpha-defensins) to cold stress were determined. RESULTS: Cold pain induced a psychological response stronger in the MS than in the LS group, but similar increases in heart rate, blood pressure, adrenocorticotrophic hormone, and cortisol, whereas estradiol and progesterone remained unaltered. Notably, the jejunal epithelium of MS females showed a chloride-related decrease in peak secretory response (Delta[15-0 minutes]: LS, 97.5 [68.4-135.0]; MS, 48.8 [36.6-65.0] microL/min/cm; P < .001) combined with a marked enhancement of albumin permeability (LS(AUC), 6.35 [0.9-9.6]; MS(AUC), 13.97 [8.3-23.1] mg/60 min; P = .008) after cold stress. Epithelial response in both groups was associated with similar increases in luminal tryptase and alpha-defensins release. CONCLUSIONS: Increased exposure to life events determines a defective jejunal epithelial response to incoming stimuli. This abnormal response may represent an initial step in the development of prolonged mucosal dysfunction, a finding that could be linked to enhanced susceptibility for IBS.

[Epidemiology of inflammatory bowel disease in the elderly]. / Epidemiología de la enfermedad inflamatoria intestinal en el paciente de edad avanzada.

INTRODUCTION: Inflammatory bowel disease has classically been considered a disorder with onset in young people. However, between 5 and 15% of patients are diagnosed when aged more than 60 years old. Epidemiological studies comparing these two age groups are controversial and consequently new studies are required to define the characteristics in each group. OBJECTIVES: To determine the epidemiological characteristics specific to Crohn's disease and ulcerative colitis in the elderly and to compare these characteristics with the form of presentation in young people in Spain. METHOD: We performed a case-control, descriptive study. Patients with inflammatory bowel disease registered in the database of the Crohn-Colitis Unit were included. The patients were stratified in two groups according to age at symptom onset: the first group consisted of patients with onset at age 60 years or above and the second group was a control group consisting of patients aged less than 60 years old. The control group was composed of two patients for each case matched by sex and diagnosis. RESULTS: Thirty-three cases aged more than 60 years old (4.1%) were included, eight with Crohn's disease and 25 with ulcerative colitis. The control group included 66 patients (16 with Crohn's disease and 50 with ulcerative colitis). Statistically significant differences were observed between the two groups both in the form of presentation (tenesmus and occlusive symptoms were more frequent and abdominal pain was less frequent in the group aged more than 60 years than in the control group) and in treatment response (corticosteroid dependency and refractoriness and requirement for immunosuppressive treatment were more frequent in the elderly). CONCLUSION: The results of the present study suggest that there are epidemiological differences in inflammatory bowel disease among the elderly, notably a lower frequency of abdominal pain and a lower rate of refractoriness to steroid treatment.

Tocotrienols induce apoptosis and autophagy in rat pancreatic stellate cells through the mitochondrial death pathway.

BACKGROUND & AIMS: Selective removal of activated pancreatic stellate cells (PSCs) through induction of their own programmed death is a goal of therapeutic interest in patients with chronic pancreatitis. Here, we investigated the effects of tocotrienols on PSC death outcomes. METHODS: Activated and quiescent PSCs and acinar cells from rat pancreas were treated with vitamin E derivatives alpha-tocopherol; individual alpha-, beta-, gamma-, and delta-tocotrienols; and a tocotrienol rich fraction (TRF) from palm oil. RESULTS: TRF, but not alpha-tocopherol, reduced viability of activated PSC by setting up a full death program, independent of cell cycle regulation. Activated PSCs died both through apoptosis, as indicated by increased DNA fragmentation and caspase activation, and through autophagy, as denoted by the formation of autophagic vacuoles and LC3-II accumulation. In contrast to alpha-tocopherol, TRF caused an intense and sustained mitochondrial membrane depolarization and extensive cytochrome c release. Caspase inhibition with zVAD-fmk suppressed TRF-induced apoptosis but enhanced autophagy. However, mitochondrial permeability transition pore blockade with cyclosporin A completely abolished the deadly effects of TRF. beta-, gamma-, and delta-tocotrienol, but not alpha-tocotrienol nor alpha-tocopherol, reproduced TRF actions on activated PSCs. TRF death induction was restricted to activated PSCs because it did not cause apoptosis either in quiescent PSCs or in acinar cells. CONCLUSIONS: Tocotrienols selectively trigger activated pancreatic stellate cell death by targeting the mitochondrial permeability transition pore. Our findings unveil a novel potential for tocotrienols to ameliorate the fibrogenesis associated with chronic pancreatitis.

Sustained improvement of health-related quality of life in Crohn's disease patients treated with infliximab and azathioprine for 4 years.

BACKGROUND: Infliximab induces remission and improves the health-related quality of life (HRQOL) of patients with refractory or fistulous Crohn's disease (CD). However, little information is available as to whether its effect on HRQOL is sustained over time. The objective was to measure the HRQOL of CD patients in long-term clinical remission. METHODS: Prospective, observational study was undertaken in patients with CD in infliximab-induced clinical remission (Harvey index <3) for at least 6 months, and receiving long-term infliximab and azathioprine maintenance therapy. Patients were followed for 4 years or until clinical relapse (Harvey index >3). HRQOL was assessed annually using the validated Spanish version of the disease-specific 36-item Inflammatory Bowel Disease Questionnaire (IBDQ-36) and the EuroQol-5D. RESULTS: Forty-nine patients with CD in stable clinical remission were included at baseline. At 12 months, n = 42 patients remained in remission, at 24 months n = 32 patients, at 36 months n = 13, and in the last visit at 48 months 6 patients remained in clinical remission. The overall score on the IBDQ-36 remained unchanged in patients with stable, inactive CD (median overall score of 6.1 at baseline and 6.5 at 4 years). Scores on all 5 dimensions of the IBDQ-36 remained unchanged over the study period in stable patients. Patients in remission scored highly on the preference value ratings of the EuroQol-5D (scores of 1.0) and remained unchanged in patients who remained in remission. CONCLUSIONS: Sustained clinical remission of CD achieved with maintenance treatment maintains HRQOL over long-term follow-up.

Long-term efficacy of octreotide in the prevention of recurrent bleeding from gastrointestinal angiodysplasia.

OBJECTIVES: Preliminary studies suggested that octreotide may be therapeutic in bleeding angiodysplasia. Our aim was to investigate the efficacy of long-term octreotide therapy in the prevention of rebleeding from gastrointestinal angiodysplasia. METHODS: A cohort of 32 patients diagnosed with bleeding from angiodysplasia was treated with octreotide 50 mu 12 h subcutaneously for a 1-2 yr period. This cohort was compared with an external control group (38 patients who had received placebo [1 tablet/day] in a concurrent randomized clinical trial for the same period. RESULTS: Two patients of the octreotide group were lost to follow-up. Treatment failure occurred in seven of 30 (23%) patients in the octreotide group and in 17 of 35 (48%) in the placebo group (three dropouts before first visit) (P= 0.043). The actuarial probability of remaining free of rebleeding at 1 and 2 yr of follow-up was 77% and 68%, respectively, for the octreotide group and 55% and 36%, respectively, for the placebo group (log rank P= 0.030). Multivariate proportional hazards-regression analysis showed that octreotide therapy and previous bleeding episodes were positive and negative predictors of efficacy, respectively. No significant differences between the groups were observed according to number of bleeding episodes (0.4 +/- 0.7 vs 0.9 +/- 1.5, P= 0.070) and transfusion requirements (1.1 +/- 2.6 vs 0.7 +/- 1.5 units); however, iron requirements were lower in the octreotide than in the placebo group (22 +/- 62 vs 166 +/- 267 units; P < 0.001). Likewise, major adverse events (1 vs 1) and mortality (0 vs 1) were similar between groups. CONCLUSIONS: This study suggests that octreotide treatment may be beneficial in preventing rebleeding from gastrointestinal angiodysplasia.

Diarrhoea-predominant IBS patients show mast cell activation and hyperplasia in the jejunum.

BACKGROUND: Increased numbers of mast cells and mast cell activation in distal gut segments are associated with symptom onset and severity in irritable bowel syndrome (IBS). Although upper gut symptoms are common, mast cells have not been thoroughly evaluated in proximal gut in IBS patients. METHODS: Jejunal biopsies obtained by Watson's capsule, aspiration of intestinal fluid and one blood sample were obtained in 20 diarrhoea-predominant patients with IBS (D-IBS) and 14 healthy volunteers (H). Psychological stress (Holmes-Rahe Scale) and depression (Beck's Depression Inventory) were evaluated at baseline and food and respiratory allergy excluded. Biopsies were processed for H&E staining and microscopic inflammation assessed by counting intraepithelial lymphocytes. Mast cells in lamina propria were counted by immunohistochemistry with CD117 (c-kit). Tryptase concentration was measured in intestinal fluid and serum. RESULTS: D-IBS patients showed higher psychological stress than healthy volunteers (D-IBS: 203 (SD 114) v H: 112 (SD 99); p = 0.019). Immunohistochemical staining of jejunal mucosa revealed mild increase in intraepithelial CD3+ cells in D-IBS patients (D-IBS: 15.3 (SD 5.5; 95% CI 12.7 to 17.9) v H: 10.3 (SD 3.9; 95% CI 8.0 to 12.5); p = 0.006). Moreover, D-IBS patients showed marked increase in mast cells numbers (D-IBS: 34 (SD 9.3); H: 15.3 (SD 4.4) mast cells/hpf; p<0.001) and higher tryptase concentration in jejunal fluid (D-IBS: 0.45 (SD 0.38); H: 0.09 (SD 0.10) microg/l; p = 0.005). Upper gut symptoms were not associated with gender, mast cell counts, jejunal tryptase or basal stress. CONCLUSION: This jejunal mucosal inflammatory profile may help identify diarrhoea-predominant IBS, a stress-related disorder.

Modulatory effect of nitric oxide on mast cells during induction of dextran sulfate sodium colitis.

Nitric oxide (NO) is implicated in the pathophysiology of intestinal inflammation. Intestinal mast cells may amplify inflammatory response and mucosal injury in inflammatory bowel disease. Our aim was to examine the role of NO and intestinal mast cells by investigating the effects of NO synthase (NOS) inhibitors and a mast cell stabilizer during induction of dextran sulfate sodium (DSS) colitis. Colitis was induced by 4% DSS in drinking water, in rats pretreated with L-NAME or aminoguanidine. In another set of experiments, we investigated the effect of ketotifen in this setting. Inhibition of NO by L-NAME worsened DSS-induced inflammation, however, aminoguanidine had no effect. On the other hand, ketotifen abolished the deleterious effects of L-NAME on colonic inflammation, suggesting that hyperactivation of mast cells by NOS inhibition amplifies mucosal injury induced by DSS. Our results suggest that constitutive isoforms of NOS prevent mast cell activation.

Targeting mast cells in the treatment of functional gastrointestinal disorders.

Enhanced knowledge of the pathophysiological basis of functional gastrointestinal disorders indicates that low-grade mucosal inflammation and mast cell hyperplasia are common findings. Mast cells are multipotent and mucosa-dwelling residents are uniquely located to communicate with host immune and nervous supersystems and with the gut microflora to provide tight microenvironmental conditions. Maintenance of homeostasis within this integrated defense system is crucial for symbiotic health, whereas breakdown of that balance might lead to uncontrolled mucosal and systemic inflammation. Numerous advances have recently emerged in the understanding of regulatory mechanisms of mast cell activation, development and homing to mucosal surfaces, as well as of the role of mast cells in key steps of mucosal inflammation. Such observations have stimulated the development of candidate drugs, such as tryptase or Syk inhibitors, that might be useful for the treatment of gastrointestinal functional disorders.

Lactobacillus casei prevents the upregulation of ICAM-1 expression and leukocyte recruitment in experimental colitis.

Lactobacillus casei has been shown to attenuate the severity of experimental colitis. The objective of the present study was to determine whether the effects of L. casei on colitis are related to modulation of leukocyte recruitment into the inflamed intestine. Rats with a colonic segment excluded from fecal transit were surgically prepared. The segment was decontaminated with antibiotics and recolonized with normal flora isolated from the inflamed rat colon, associated or not to L. casei. Control and colitic [2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced] animals were studied. Leukocyte-endothelial cell interactions were characterized in the colonic microcirculation by intravital microscopy, and ICAM-1 and VCAM-1 expression was measured by the radiolabeled antibody technique. Compared with the noninflamed colonic segment, induction of colitis by TNBS provoked a marked increase in the number of leukocytes firmly adherent to the venular wall (0.5 +/- 0.1 vs. 2.1 +/- 0.6 leukocytes/100 mum, P < 0.01). Colonization with L. casei significantly reduced the number of adherent leukocytes (1.3 +/- 0.4 leukocytes/100 mum; P < 0.05) but did not affect the increased rolling interactions associated with the induction of colitis. Compared with the noncolitic group, induction of colitis was associated with a marked increase in ICAM-1 expression (117 +/- 4 vs. 180 +/- 3 ng antibody/g tissue) that was abrogated when the colitic segment was colonized by L. casei (117 +/- 3 ng antibody/g tissue, P < 0.05). However, L. casei administration did not modify VCAM-1 upregulation in colitic animals. L. casei attenuates leukocyte recruitment observed in experimental colitis induced by TNBS. This effect is possibly related to abrogation of ICAM-1 upregulation.

Association between achalasia and nitric oxide synthase gene polymorphisms.

BACKGROUND: Our group previously reported the absence of nitric oxide synthase (NOS) in the gastroesophageal junction of patients with achalasia. NOS exists in three distinct isoforms: neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible isoform (iNOS). Some studies have shown that NO production is regulated by NOS polymorphisms. AIM: To assess whether some functional polymorphisms in the nNOS, iNOS, or eNOS genes are involved in susceptibility to suffer from achalasia. METHODS: Genomic DNA from 80 unrelated Spanish Caucasian patients with sporadic achalasia and 144 healthy subjects matched for age (+/-5 yr) and gender was typed by PCR and RFLP methods for the 27-bp variable number of tandem repeat (VNTR) polymorphism in intron 4 of the eNOS gene, a CA microsatellite repeat and a Nla III (C-->T) restriction fragment length polymorphism (RFLP) in exon 29 of the nNOS gene, and two nucleotide substitutions located in exon 16 (C-->T) and exon 22 (G-->A) of the iNOS gene. RESULTS: No significant differences in carriage, genotype, and allele frequencies of the nNOS, iNOS, or eNOS gene polymorphisms were found between patients with achalasia and controls. Individuals homozygous for genotype iNOS22*A/A tended to be more frequent in achalasia (20%vs 11%, odds ratio [OR] 1.79, 95% confidence interval [CI] 0.89-3.59, p= 0.09) as were those homozygous for the rare eNOS*4a allele (6.2%vs 1.4%, OR 4.5, 95% CI 0.89-22.67, p= 0.1) although the difference did not reach statistical significance. No differences in genotype and allele distribution were found with respect to epidemiological and clinical characteristics of patients with achalasia. CONCLUSION: Our data suggest that NOS gene polymorphisms are not involved in the susceptibility to and nature of the clinical course of sporadic achalasia. However, studies in a greater number of patients are required to analyze the tendency toward a higher prevalence of genotypes iNOS22*A/A and eNOS*4a4a.