Rare-Earth Magnets Influence Movement Patterns of the Magnetically Sensitive Nudibranch Tritonia exsulans in Its Natural Habitat

AbstractThe nudibranch Tritonia exsulans (previously Tritonia diomedea) is known to have behaviors and neurons that can be modified by perturbations of the Earth's magnetic field. There is no definitive evidence for how this magnetic sense is used in nature. Using an exploratory approach, we tested for possible effects of magnetic perturbations based on underwater video of crawling patterns in the slugs' natural habitat, with magnets of varying strength deployed on the substrate. For analysis, we used a paired comparison of tracks of animals between segments 25-50 cm distant from the magnets and segments of the same tracks 0-25 cm from the magnets, to determine whether any differences depended on the strength of the magnet. Most track measurements (length, displacement, velocity, and tortuosity) showed no such differences. However, effects were observed for the changes in track headings between successive points. These results showed that tracks had relatively higher heading variability when they moved closer to stronger magnets. We suggest that this supports a hypothesis that T. exsulans continuously uses a magnetic sense to help maintain straight-line navigation. Further specific testing of the hypothesis is now needed to verify this new possibility for how animals can benefit from a compass sense.

Health Care Provider Knowledge and Perceptions of FDA-Approved and Do-It-Yourself Automated Insulin Delivery

BACKGROUND

Automated insulin delivery (AID) technology may reduce variability in blood glucose, resulting in lower risk for hypoglycemia and associated complications, and by extension improve quality of life. While clinical trials, research, and patient experience have consistently demonstrated the value of AID, this technology is still inaccessible to many patients. Patient-driven innovation has resulted in alternative do-it-yourself (DIY) solutions to available off-the-shelf AID devices.

METHOD

This two-phase cross-sectional observational study addressed health care provider (HCP) perceptions of AID as well as the perceived need for, development of, and evaluation of an AID fact sheet comparing the most commonly used Federal Drug Administration approved AID and DIY AID devices.

RESULTS

Negative attitudes toward the use of DIY AID were low. The majority of HCPs saw their lack of knowledge about how DIY AID work to be the greatest barrier to answering patient questions about what is available (74.4%). Additionally, the majority of HCPs (64.5%) indicated they were either "likely" or "very likely" to use the fact sheet when answering patient questions about AID options.

CONCLUSION

Increased awareness and utilization of AID technology offer hope to further reduce the burden of diabetes, but there is a need to bridge the knowledge gap about DIY AID. A fact sheet provides a way to facilitate discussions of this emerging technology between HCPs and patients. Next steps could investigate additional ways to put needed information in the hands of HCPs.

Site-Specific and Temporal Effects of Apraglutide, a Novel Long-Acting Glucagon-Like Peptide-2 Receptor Agonist, on Intestinal Growth in Mice

Long-acting glucagon-like peptide-2 receptor (GLP-2R) agonists are well-established to increase intestinal growth in rodents and, most notably, humans with short bowel syndrome. Most of the trophic effects of GLP-2R agonists are reported to be mediated through increased growth of the crypt-villus axis, resulting in enhanced mucosal mass and improved intestinal function. The present study examined the effects of apraglutide, a novel GLP-2R agonist, on the growth of the small intestine and colon after 3, 7, and 10 weeks of treatment in male and female mice. Apraglutide (3 mg/kg; three times per week) significantly increased small intestinal weight (P < 0.001) and length (P < 0.001) after 3 weeks of administration, with a further increase in effectiveness after 10 weeks (P < 0.01). Crypt depth and villus height were both markedly increased after 3 weeks of apraglutide administration (P < 0.001) but did not show any further increase with duration of treatment, whereas crypt number and intestinal circumference were increased after 7 and 10 weeks (P < 0.01) but not after 3 weeks of apraglutide treatment. Both the weight and the length of the colon were also enhanced by apraglutide treatment for 3 weeks (P < 0.001), and these effects were maintained but did not improve further with continued apraglutide administration. The results of this study demonstrate that the novel, long-acting GLP-2R agonist, apraglutide, demonstrates an unexpected marked ability to increase intestinal length as well as exert time- and location-dependent specificity in its intestinotrophic actions. SIGNIFICANCE STATEMENT: The novel long-acting glucagon-like peptide 2 receptor agonist, apraglutide, enhances intestinal weight as well as intestinal length in a time- and site-dependent fashion.

Early Management of Laryngeal Injuries

The results of acute laryngeal trauma sustained by 44 patients are reported. Three major aetiological groups are identified: road traffic accidents, blunt injury and penetrating injury. Road traffic accidents appear to produce severe injury, but the long-term follow-up results are similar to those laryngeal injuries which were not recognized initially and who developed a chronic stenosis. The blunt injury group sustained less forceful trauma; 14 of the 18 were treated conservatively and all patients had a good result. The majority of the penetrating injury group developed good breathing and a good voice following operation. Some of the technical expertise normally used to treat chronic laryngeal stenosis has been included in this series to good effect.

The Uvulopalatopharyngoplasty Operation: The Edinburgh Experience

The experience of the uvulopalatopharyngoplasty operation, performed on 24 patients for the relief of loud or heroic snoring, is presented. The operation successfully reduced the severity of snoring in 96% of patients. Postoperative complications were uncommon but included nasal regurgitation and intrapharyngeal adhesions in one patient. The role of the uvulopalatopharyngoplasty operation in the treatment of obstructive sleep apnoea is undecided but the authors do not perform this operation on such patients.

Undetectable negative tissue transglutaminase IgA antibodies predict mucosal healing in treated coeliac disease patients

BACKGROUND

Tissue transglutaminase (tTG) immunoglobulin A (IgA) testing is a sensitive adjunct to the diagnosis of coeliac disease. The threshold for positivity was developed for diagnosis, with negative results reported as below the reference value (<4 U/mL).

AIM

To investigate if an undetectable (tTG IgA<1.2 U/mL) is more predictive of healing compared to patients with negative but detectable serology (1.2-3.9 U/mL).

METHODS

We performed a retrospective study of 402 treated coeliac disease patients seen at the Mayo Clinic with negative tTG IgA values drawn within 1 month of duodenal biopsy between January 2009 and December 2015. The Corazza-Villanacci score was used to assess mucosal healing. The presence of gastrointestinal symptoms was also collected. Logistic regression was used to assess the relationship of clinical variables with a normal biopsy.

RESULTS

Patients with undetectable titres more frequently had normal duodenal histology compared to patients with detectable tTG IgA levels (117/240 vs. 53/162; OR=1.96; 1.292, 2.961). Asymptomatic patients more frequently had normal duodenum as compared to symptomatic patients (88/163 vs. 82/239; OR=2.25; CI: 1.494, 3.377). Patients with undetectable serology and on a gluten-free diet for ≥2 years were more likely to have no villous atrophy compared to patients with detectable serology (148/192 vs. 55/88; OR=2.02; CI: 1.17, 3.49).

CONCLUSION

In subjects recovering from coeliac disease with negative tTG IgA serology, an undetectable titre is associated with normal histology on follow-up biopsy.

Factors associated with villus atrophy in symptomatic coeliac disease patients on a gluten-free diet

BACKGROUND

Duodenal injury persists in some coeliac disease patients despite gluten-free diet, and is associated with adverse outcomes.

AIM

To determine the prevalence and clinical risk factors for persistent villus atrophy among symptomatic coeliac disease patients.

METHODS

A nested cross-sectional analysis was performed on coeliac disease patients with self-reported moderate or severe symptoms while following a gluten-free diet, who underwent protocol-mandated duodenal biopsy upon enrolment in the CeliAction clinical trial. Demographic factors, symptom type, medication use, and serology were examined to determine predictors of persistent villus atrophy.

RESULTS

Of 1345 symptomatic patients, 511 (38%, 95% CI, 35-41%) were found to have active coeliac disease with persistent villus atrophy, defined as average villus height to crypt depth ratio ≤2.0. On multivariable analysis, older age (OR, 5.1 for ≥70 vs. 18-29 years, 95% CI, 2.5-10.4) was a risk factor while longer duration on gluten-free diet was protective (OR, 0.37, 95% CI, 0.24-0.55 for 4-5.9 vs. 1-1.9 years). Villus atrophy was associated with use of proton-pump inhibitors (PPIs; OR, 1.6, 95% CI, 1.1-2.3), non-steroidal anti-inflammatory drugs (NSAIDs; OR, 1.64, 95% CI, 1.2-2.2), and selective serotonin reuptake inhibitors (SSRIs; OR, 1.74, 95% CI, 1.2-2.5). Symptoms were not associated with villus atrophy after adjusting for covariates. Conclusions A majority of symptomatic coeliac disease patients did not have active disease on follow-up histology. Symptoms were poorly predictive of persistent mucosal injury. The impact of NSAIDs, PPIs, and SSRIs on mucosal healing in coeliac disease warrants further study.

Serum alkylresorcinols as biomarkers of dietary gluten exposure in coeliac disease

BACKGROUND

Therapy for coeliac disease (CD) mainly relies on following a gluten-free diet (GFD); however, a serum marker for gluten intake has yet to be established.

AIM

To evaluate the utility of alkylresorcinol concentrations for detecting gluten intake in studies of human and mouse.

METHODS

Alkylresorcinol concentrations were compared among treated patients with coeliac disease (n = 34), untreated coeliac disease patients (n = 36) and controls (n = 33). Furthermore, seven additional coeliac disease patients whose serum samples were available at diagnosis and after GFD were evaluated. In mice studies, alkylresorcinol concentrations were compared in the serum of five mice fed a regular chow and 10 mice fed lifelong with a gluten-free chow. In addition, the effect of adding gluten on changes of alkylresorcinol concentrations was also evaluated.

RESULTS

Total alkylresorcinol concentrations were significantly lower in treated with coeliac disease [median (IQR), 3 (2-8) nmol/L], compared to untreated patients [median (IQR), 32 (11-74) nmol/L; P < 0.0001] or healthy controls [median (IQR), 54 (23-112) nmol/L; P < 0.0001]. Moreover, alkylresorcinol concentrations in coeliac disease patients significantly decreased after introduction of a GFD (median, 34 nmol/L at diagnosis vs. 5 nmol/L after GFD, P = 0.02). In the mice, median (IQR) total alkylresorcinol concentrations in serum samples of mice fed lifelong with a gluten-free chow was 1.8 (1.6-2.3) nmol/L, which was further significantly increased to 16 (11-22) nmol/L after 8 days of feeding with the gluten-free chow that had gluten added to it. (P = 0.008).

CONCLUSION

Serum alkylresorcinol concentrations could be a useful marker for dietary gluten in coeliac disease.

Presence of intraepithelial food antigen in patients with active eosinophilic oesophagitis

BACKGROUND

Although eosinophilic oesophagitis (EoE) is putatively mediated by an abnormal response to food antigen, the oesophagus is considered relatively impermeable to large molecules.

AIM

To assess whether food antigens penetrate the oesophageal mucosa in patients with EoE.

METHODS

Anti-gliadin staining was performed in three groups: active EoE, inactive EoE and EoE patients on a low or gluten free diet. To appraise the specificity of our results, we also performed gliadin staining on six patients without oesophageal disease who were consuming gluten. The groups with EoE on gluten also underwent endoscopic infusion with gluten containing soy sauce and repeat biopsies during the endoscopy. We measured eosinophil density, dilated intercellular spaces (on a 0-4+ scale) and gliadin in oesophageal mucosa by immunofluorescence.

RESULTS

Patients with active EoE had significantly greater epithelial density of anti-gliadin staining when compared to inactive EoE (P < 0.0065) and gluten-free patients (P < 0.0008) at baseline and after soy infusion. Gliadin was not detected in non-EoE control patients. The distribution of gliadin was both cytoplasmic and nuclear. There was good correlation of dilated intercellular spaces grade and total gliadin staining intensity (r = 0.577, P = 0.0077). Acute oesophageal perfusion of a commercial gliadin-rich soy sauce did not lead to an increase in gliadin staining in active or inactive EoE.

CONCLUSION

These findings suggest, although do not prove, that antigen penetration in active eosinophilic oesophagitis might be facilitated by impairment of epithelial integrity.

Oesophageal lichen planus: the efficacy of topical steroid-based therapies

BACKGROUND

Oesophageal lichen planus is an idiopathic inflammatory disorder characterized by significant oesophageal stricturing. Oesophageal lichen planus is a rare, difficult to diagnose, and likely an under recognized disease. As a result, there is no standardized approach to therapy and treatment strategies vary.

AIM

To examine the utility of topical steroid therapy (fluticasone or budesonide) in the management of oesophageal lichen planus.

METHODS

A retrospective chart review was conducted of patients diagnosed with oesophageal lichen planus who underwent baseline and follow up endoscopy pre and post topical steroid therapy between 1995 and 2016 at Mayo Clinic, Rochester MN. Average time between upper GI endoscopy was 3.2 months (0.7-11.7). Swallowed steroid preparations included fluticasone 880 μg twice daily or budesonide 3 mg twice daily. Patients were reviewed for symptomatic response to therapy using the Dakkak-Bennett dysphagia score (0-4, no dysphagia to total aphagia). Pre- and post-endoscopic findings were assessed. Additional baseline demographic, endoscopic, and histologic data were also obtained.

RESULTS

We identified 40 patients who met the inclusion criteria. A significant reduction in median dysphagia score from 1 (0-4) to 0 (0-3) after steroid therapy (P < 0.001) was noted. 62% of patients reported resolution of their dysphagia after receiving topical corticosteroids. 72.5% had an endoscopic response to steroid therapy.

CONCLUSION

Topical swallowed budesonide or fluticasone appear to effective treatment for oesophageal lichen planus.

Improving the detection of environmental enteric dysfunction: a lactulose, rhamnose assay of intestinal permeability in children aged under 5 years exposed to poor sanitation and hygiene

Background

Environmental enteric dysfunction (EED) is an asymptomatic intestinal disorder affecting populations living in conditions of poor sanitation and hygiene. The study tested intestinal barrier function in infants with EED.

Methods

We prospectively studied an advanced high-performance liquid chromatography mass spectrometry assay of urine collected after oral intake of the monosaccharide, L-rhamnose and the disaccharide, lactulose, in 112 children from three continents.

Findings

Compared to the US cohort (n=27), the cohorts of children from Peru (n=19) and Zambia (n=85) were older with evidence of growth impairment. The median (range) of age (months) was 8.0 (2.0 to 13.0), 27.0 (15.0 to 29.0) and 21.0 (12.0 to 36.0), respectively. The median (range) of height for age Z score was −0.1 (−1.8 to 2.4), −1.8 (−3.3 to −0.2) and −2.3 (−8.5 to 1.2), respectively. Among children with valid sugar data (n=22 USA, n=19 Peru, n=73 Zambia), there were no significant differences in the median rhamnose urine concentrations between the three groups. The median (range) lactulose concentration (µg/mL) was 6.78 (0.29 to 31.90), 47.60 (4.23 to 379.00) and 75.40 (0.67 to 873.00) in the US, Peruvian and Zambian cohorts, respectively (p<0.001). The lactulose/rhamnose ratio (LRR) was higher in cohorts from Peru (0.75, 0.15, 5.02) and Zambia (2.26, 0.08, 14.48) compared to the US (0.14, 0.06, 1.00) cohort (p<0.001). In a multivariate effect modification model, higher weight-for-age z scores were associated with lower post-dose lactulose when rhamnose excretion was constant (p=0.003).

Conclusions

This non-invasive two saccharide permeability protocol measures changes in intestinal permeability in children with EED and permits the identification of individuals for interventional trials.

Serologic microbial associated markers can predict Crohn's disease behaviour years before disease diagnosis

BACKGROUND

Patients with Crohn's disease (CD) have serologic responses to various microbial antigens. Serologic markers are associated with aggressive forms of disease and can be detected before onset of symptoms. Their utility in pre-clinical disease or prediction of complicated disease course before diagnosis is unclear.

AIM

To evaluate the pattern of serologic anti-microbial antibodies long prior to diagnosis and the subsequent risk of complicated Crohn's disease at diagnosis.

METHODS

Sera from 100 US military personnel with Crohn's disease were obtained from the Department of Defense Serum Repository. For each patient, four samples were obtained at different time points before and around diagnosis, and were tested for 6 microbiota-directed antibodies (ASCA-IgA, ASCA-IgG, anti-OmpC, anti-CBir1, anti-A4-Fla2 and anti-FlaX). Associations between the presence and accumulation of Crohn's disease anti-microbial antibodies before diagnosis and with the later development of complications were evaluated.

RESULTS

Overall, 65 patients were positive for at least one Crohn's disease associated anti-microbial antibody in the earliest available sample, at a median of 6 years before Crohn's disease diagnosis (interquartile range, 5.6-8.2). The number of positive anti-microbial antibodies increased up to the time of Crohn's disease diagnosis. Complicated disease developed around the time of diagnosis in 24 patients. The proportion of positive antimicrobial antibodies before diagnosis was higher in patients with complicated vs. noncomplicated Crohn's disease. There was an inverse relationship between the time to first complication and the magnitude of serologic response before diagnosis.

CONCLUSION

The presence and accumulation of circulating anti-microbial antibodies years before Crohn's disease diagnosis was associated with complicated Crohn's disease at or shortly after diagnosis.

Supraesophageal Reflux: Validation of a Symptom Questionnaire

OBJECTIVES: To develop and validate a questionnaire for supraesophageal manifestations of reflux (SER) that will facilitate its study in clinical and research settings.

STUDY DESIGN: The Supraesophageal Reflux Questionnaire (SERQ) and previously validated Reflux Symptom Index (RSI) were subjected to multiple types of validity testing, including content validity, concurrent validity, reproducibility, and predictive validity.

RESULTS: The concurrent validity and reproducibility of both instruments was good to excellent for most items tested. The predictive validity of the SERQ was superior to the RSI when it included the covariates of history of sinusitis, use of over-the-counter antacid medications, age, gender, and body mass index.

CONCLUSIONS: The SERQ will serve as both a useful clinical and research tool by offering not only SER symptom information, like the RSI, but also information about the patient's medical history and medication usage that will facilitate use of the SERQ in research protocols.

EBM rating: B-2b

Achalasia and chronic opiate use: innocent bystanders or associated conditions?

High-resolution manometry identifies three subtypes of achalasia. However, type 3 differs from classic achalasia. Although opiates affect esophageal motility, opiate use and achalasia have not been studied. Patients with a new diagnosis of achalasia at Mayo Clinic Rochester between June 1, 2012 and January 3, 2014 were identified. Clinical records were reviewed to assess symptoms, opiate use, and therapy. Fifty-six patients with achalasia were identified, 14 (25%) were on opiates. Opiate prescription was unrelated to achalasia in all cases, with chronic back and joint pain constituting the majority. Of patients on opiates, five (36%) had type 3 achalasia compared with four (10%) not on opiates (P = 0.02). No patients on opiates had type 1 achalasia. Clinical presentation did not differ with opiates, although those on opiates were more likely to report chest pain (39 vs. 14%, P = 0.05) and less likely to have esophageal dilation (62 vs. 82%, P = 0.13), none with greater than 5-cm diameter. Contractile vigor was greater with opiate use, with distal contractile integral of 7149 versus 2615.5 mmHg/cm/second (P = 0.08). Treatment response was inferior on opiates, with persistent symptoms in 22% compared with 3% without opiates (P = 0.06). Opiate use is common in type 3 achalasia, with the majority of patients on opiates. No patients on opiates were diagnosed with type 1 achalasia. Manometric findings of type 3 achalasia mimic those induced by opiates, suggesting a physiologic mechanism for opiate induced type 3 achalasia. Treatment outcome is inferior with opiates, with opiate cessation perhaps preferable. Further studies assessing opiate use and achalasia are needed.

The Mitochondrial Genomes of the Nudibranch Mollusks, Melibe leonina and Tritonia diomedea, and Their Impact on Gastropod Phylogeny

The phylogenetic relationships among certain groups of gastropods have remained unresolved in recent studies, especially in the diverse subclass Opisthobranchia, where nudibranchs have been poorly represented. Here we present the complete mitochondrial genomes of Melibe leonina and Tritonia diomedea (more recently named T. tetraquetra), two nudibranchs from the unrepresented Cladobranchia group, and report on the resulting phylogenetic analyses. Both genomes coded for the typical thirteen protein-coding genes, twenty-two transfer RNAs, and two ribosomal RNAs seen in other species. The twelve-nucleotide deletion previously reported for the cytochrome oxidase 1 gene in several other Melibe species was further clarified as three separate deletion events. These deletions were not present in any opisthobranchs examined in our study, including the newly sequenced M. leonina or T. diomedea, suggesting that these previously reported deletions may represent more recently divergent taxa. Analysis of the secondary structures for all twenty-two tRNAs of both M. leonina and T. diomedea indicated truncated d arms for the two serine tRNAs, as seen in some other heterobranchs. In addition, the serine 1 tRNA in T. diomedea contained an anticodon not yet reported in any other gastropod. For phylogenetic analysis, we used the thirteen protein-coding genes from the mitochondrial genomes of M. leonina, T. diomedea, and seventy-one other gastropods. Phylogenetic analyses were performed for both the class Gastropoda and the subclass Opisthobranchia. Both Bayesian and maximum likelihood analyses resulted in similar tree topologies. In the Opisthobranchia, the five orders represented in our study were monophyletic (Anaspidea, Cephalaspidea, Notaspidea, Nudibranchia, Sacoglossa). In Gastropoda, two of the three traditional subclasses, Opisthobranchia and Pulmonata, were not monophyletic. In contrast, four of the more recently named gastropod clades (Vetigastropoda, Neritimorpha, Caenogastropoda, and Heterobranchia) were all monophyletic, and thus appear to be better classifications for this diverse group.

The effect of age on the key parameters in the Chicago classification: a study using high-resolution esophageal manometry in asymptomatic normal individuals

BACKGROUND

High-resolution manometry using the Chicago classification, which utilizes parameters including integrated relaxation pressure (IRP), distal contractile integral (DCI), and contractile front velocity (CFV), shows better diagnostic ability than previous conventional criteria. However, the current normal cut-off values for the Chicago classification are based on individuals aged 19-48 years and do not include older people. Here, we aimed to assess the normal values for the Chicago classification in individuals aged 20-67 years and compare the parameters across age groups.

METHODS

Fifty-four asymptomatic healthy individuals (27 male and 27 female; age range. 20-67 years) were prospectively enrolled. To evaluate the effect of age and sex on manometric profiles, we attempted to enroll equal numbers of male and female subjects for each decade. Manometry was performed in both the supine and sitting positions.

KEY RESULTS

The distal latency (DL) was significantly shorter with increasing age in both measurement positions. Furthermore, IRP was significantly higher with increasing age in both positions. Spearman's ranked correlation coefficient analysis indicated that DCI and IRP in both positions were positively correlated with age.

CONCLUSIONS & INFERENCES

Age affects the key parameters currently used in the Chicago classification, including IRP, DCI, and DL. Larger prospective studies with older subjects are needed to determine the age-related normal values for the Chicago classification system.

Immunotherapy trial as diagnostic test in evaluating patients with presumed autoimmune gastrointestinal dysmotility

BACKGROUND

Chronic gastrointestinal dysmotility greatly impacts the quality of life. Treatment options are limited and generally symptomatic. Neural autoimmunity is an under-recognized etiology. We evaluated immunotherapy as an aid to diagnosing autoimmune gastrointestinal dysmotility (AGID).

METHODS

Twenty-three subjects evaluated at the Mayo Clinic for suspected AGID (August 2006-February 2014) fulfilled the following criteria: (1) prominent symptoms of gastrointestinal dysmotility with abnormalities on scintigraphy-manometry; (2) serological evidence or personal/family history of autoimmune disease; (3) treated by immunotherapy on a trial basis, 6-12 weeks (intravenous immune globulin, 16; or methylprednisolone, 5; or both, 2). Response was defined subjectively (symptomatic improvement) and objectively (gastrointestinal scintigraphy/manometry studies).

KEY RESULTS

Symptoms at presentation: constipation, 18/23; nausea or vomiting, 18/23; weight loss, 17/23; bloating, 13/23; and early satiety, 4/23. Thirteen patients had personal/family history of autoimmunity. Sixteen had neural autoantibodies and 19 had extra-intestinal autonomic testing abnormalities. Cancer was detected in three patients. Preimmunotherapy scintigraphy revealed slowed transit (19/21 evaluated; gastric, 11; small bowel, 12; colonic, 11); manometry studies were abnormal in 7/8. Postimmunotherapy, 17 (74%) had improvement (both symptomatic and scintigraphic, five; symptomatic alone, eight; scintigraphic alone, four). Nine responders re-evaluated had scintigraphic evidence of improvement. The majority of responders who were re-evaluated had improvement in autonomic testing (six of seven) or manometry (two of two).

CONCLUSIONS & INFERENCES

This proof of principle study illustrates the importance of considering an autoimmune basis for idiopathic gastrointestinal dysmotility and supports the utility of a diagnostic trial of immunotherapy.

Larazotide acetate in patients with coeliac disease undergoing a gluten challenge: a randomised placebo-controlled study

BACKGROUND

Coeliac disease, an autoimmune disorder triggered by gluten ingestion, is managed by a gluten-free diet (GFD), which is difficult for many patients. Larazotide acetate is a first-in-class oral peptide that prevents tight junction opening, and may reduce gluten uptake and associated sequelae.

AIM

To evaluate the efficacy and tolerability of larazotide acetate during gluten challenge.

METHODS

This exploratory, double-blind, randomised, placebo-controlled study included 184 patients maintaining a GFD before and during the study. After a GFD run-in, patients were randomised to larazotide acetate (1, 4, or 8 mg three times daily) or placebo and received 2.7 grams of gluten daily for 6 weeks. Outcomes included an experimental biomarker of intestinal permeability, the lactulose-to-mannitol (LAMA) ratio and clinical symptoms assessed by Gastrointestinal Symptom Rating Scale (GSRS) and anti-transglutaminase antibody levels.

RESULTS

No significant differences in LAMA ratios were observed between larazotide acetate and placebo groups. Larazotide acetate 1-mg limited gluten-induced symptoms measured by GSRS (P = 0.002 vs. placebo). Mean ratio of anti-tissue transglutaminase IgA levels over baseline was 19.0 in the placebo group compared with 5.78 (P = 0.010), 3.88 (P = 0.005) and 7.72 (P = 0.025) in the larazotide acetate 1-, 4-, and 8-mg groups, respectively. Adverse event rates were similar between larazotide acetate and placebo groups.

CONCLUSIONS

Larazotide acetate reduced gluten-induced immune reactivity and symptoms in patients with coeliac disease undergoing gluten challenge and was generally well tolerated; however, no significant difference in LAMA ratios between larazotide acetate and placebo was observed. Results and design of this exploratory study can inform the design of future studies of pharmacological interventions in patients with coeliac disease.

A randomized, double-blind study of larazotide acetate to prevent the activation of celiac disease during gluten challenge

OBJECTIVES

In patients with celiac disease, enteropathy is caused by the entry of gluten peptides into the lamina propria of the intestine, in which their immunogenicity is potentiated by tissue transglutaminase (tTG) and T-helper type 1-mediated immune responses are triggered. Tight junction disassembly and paracellular permeability are believed to have an important role in the transport of gluten peptides to the lamina propria. Larazotide acetate is a tight-junction regulator peptide that, in vitro, prevents the opening of intestinal epithelial tight junctions. The aim of this study was to evaluate the efficacy and tolerability of larazotide acetate in protecting against gluten-induced intestinal permeability and gastrointestinal symptom severity in patients with celiac disease.

METHODS

In this dose-ranging, placebo-controlled study, 86 patients with celiac disease controlled through diet were randomly assigned to larazotide acetate (0.25, 1, 4, or 8 mg) or placebo three times per day with or without gluten challenge (2.4 g/day) for 14 days. The primary efficacy outcome was the urinary lactulose/mannitol (LAMA) fractional excretion ratio. Secondary endpoints included gastrointestinal symptom severity, quality-of-life measures, and antibodies to tTG.

RESULTS

LAMA measurements were highly variable in the outpatient setting. The increase in LAMA ratio associated with the gluten challenge was not statistically significantly greater than the increase in the gluten-free control. Among patients receiving the gluten challenge, the difference in the LAMA ratios for the larazotide acetate and placebo groups was not statistically significant. However, larazotide acetate appeared to limit gluten-induced worsening of gastrointestinal symptom severity as measured by the Gastrointestinal Symptom Rating Scale at some lower doses but not at the higher dose. Symptoms worsened significantly in the gluten challenge-placebo arm compared with the placebo-placebo arm, suggesting that 2.4 g of gluten per day is sufficient to induce reproducible gluten toxicity. Larazotide acetate was generally well tolerated. No serious adverse events were observed. The most common adverse events were headache and urinary tract infection.

CONCLUSIONS

LAMA variability in the outpatient setting precluded accurate assessment of the effect of larazotide acetate on intestinal permeability. However, some lower doses of larazotide acetate appeared to prevent the increase in gastrointestinal symptom severity induced by gluten challenge.

Review article: coeliac disease, new approaches to therapy

BACKGROUND

Coeliac disease is managed by life-long gluten withdrawal from the diet. However, strict adherence to a gluten-free diet is difficult and is not always effective. Novel therapeutic approaches are needed to supplement or even replace the dietary treatment.

AIM

To review recent advances in new therapeutic options for coeliac disease.

METHODS

A literature search was performed on MEDLINE, EMBASE, Web of Science, Scopus, DDW.org and ClinicalTrials.gov for English articles and abstracts. The search terms used included, but not limited to, 'Celiac disease', 'new', 'novel', 'Advances', 'alternatives' and 'Drug therapy'. The cited articles were selected based on the relevancy to the review objective.

RESULTS

Several new therapeutic approaches for coeliac disease are currently under development by targeting its underlying pathogenesis. Alternative therapies range from reproduction of harmless wheat strains to immunomodulatory approaches. Some of these therapies such as enzymatic cleavage of gluten and permeability inhibitors have shown promise in clinical studies.

CONCLUSIONS

Gluten-free diet is still the only practical treatment for patients with coeliac disease. Novel strategies provide promise of alternative adjunctive approaches to diet restriction alone for patients with this disorder.

Important lessons derived from animal models of celiac disease

Several animal models have been recently developed to recapitulate various components of the complex process that is celiac disease. In addition to the increasing diversity of murine models there are now monkey models of celiac disease. Mouse strains and protocols have been developed that are now just beginning to address the complex interactions among the innate and adaptive immune responses to gluten, as well as gluten-dependent autoimmunity in celiac disease. The most important conclusion that these models have provided us with so far is that while all three components (innate gluten sensitivity, adaptive gluten sensitivity, and autoimmunity) are independent phenomena, all are necessary for celiac disease to develop.

Co-adjuvant effects of retinoic acid and IL-15 induce inflammatory immunity to dietary antigens

Under physiological conditions the gut-associated lymphoid tissues not only prevent the induction of a local inflammatory immune response, but also induce systemic tolerance to fed antigens. A notable exception is coeliac disease, where genetically susceptible individuals expressing human leukocyte antigen (HLA) HLA-DQ2 or HLA-DQ8 molecules develop inflammatory T-cell and antibody responses against dietary gluten, a protein present in wheat. The mechanisms underlying this dysregulated mucosal immune response to a soluble antigen have not been identified. Retinoic acid, a metabolite of vitamin A, has been shown to have a critical role in the induction of intestinal regulatory responses. Here we find in mice that in conjunction with IL-15, a cytokine greatly upregulated in the gut of coeliac disease patients, retinoic acid rapidly activates dendritic cells to induce JNK (also known as MAPK8) phosphorylation and release the proinflammatory cytokines IL-12p70 and IL-23. As a result, in a stressed intestinal environment, retinoic acid acted as an adjuvant that promoted rather than prevented inflammatory cellular and humoral responses to fed antigen. Altogether, these findings reveal an unexpected role for retinoic acid and IL-15 in the abrogation of tolerance to dietary antigens.

Weakly acidic reflux

The advent of multichannel intraluminal impedance-pH (MII-pH) monitoring has generated interest in the role of weakly acidic reflux in persistent symptoms in patients with gastroesophageal reflux disease (GERD). Emerging evidence suggests that MII-pH may be superior to conventional pH testing under certain circumstances in the detection of reflux and expert opinions have been put forth advocating a central role for pH impedance monitoring in the detection of GERD. However the clinical relevance of an impedance-based diagnosis of reflux and its impact on clinically relevant outcomes is less clear. This review appraises the role of weakly acidic reflux in health and in GERD patients and the clinical utility of detecting weakly acidic reflux in the management of GERD.

Inter-observer agreement for multichannel intraluminal impedance-pH testing

Twenty-four-hour ambulatory multichannel intraluminal impedance (MII)-pH detects both acid and nonacid reflux (NAR). A computer-based program (Autoscan™, Sandhill Scientific, Highlands Ranch, CO, USA) automates the detection of reflux episodes, increasing the ease of study interpretation. Inter-observer agreement between multiple reviewers and with Autoscan™ for the evaluation of significant NAR with MII-pH has not been studied in the adult population. Twenty MII-pH studies on patients taking a proton pump inhibitor twice daily were randomly selected. Autoscan™ analyzed all studies using the same pre-programmed parameters. Four reviewers interpreted the MII-pH studies, adding or deleting reflux episodes detected by Autoscan™. Positive studies for NAR and total reflux episodes were based on published criteria. Cohen's kappa statistic (κ) evaluated inter-observer agreement between reviewers and Autoscan™ analysis. The average κ for pathologic NAR between reviewers was 0.57 (0.47-0.70), and between reviewers and Autoscan™ was 0.56 (0.4-0.8). When using the total reflux episode number as a marker for pathologic reflux (acid and NAR), the κ score was 0.72 (0.61-0.89) between reviewers, and 0.74 (0.53-0.9) when evaluating total reflux episodes. Two reviewers agreed more often with each other and with Autoscan™ on the number of NAR episodes, while the other two reviewers agreed with each other, but did not agree with either Autoscan™ or the first two reviewers. Inter-observer agreement between reviewers and Autoscan™ for detecting pathologic NAR is moderate, with reviewers either excluding more of the Autoscan™-defined events or excluding fewer events and therefore agreeing with Autoscan™.

Replication of celiac disease UK genome-wide association study results in a US population

Celiac disease is a common disease with a prevalence of approximately 1%. A recent genome-wide association study (GWAS) and follow-up study identified eight loci significantly associated with celiac disease risk. We genotyped the top 1020 non-HLA single nucleotide polymorphisms (SNPs) from the GWAS study that were genotyped in the previous follow-up study. After quality control assessments, 975 SNPs were analyzed for association with 906 celiac disease cases and 3819 controls, using logistic regression. Additional genotype data were generated by imputation and analyzed across the regions showing the strongest statistical evidence for association. Twenty SNPs were associated with celiac disease with P < 0.01 in the current study as well as in the previous follow-up study, of which 16 had P < 0.001 and 11 had P < 1 x 10(-11). Five of eight regions identified in the follow-up study were strongly associated with celiac disease, including regions on 1q31, 3q25, 3q28, 4q27 and 12q24. The strongest associations were at 4q27, the region most strongly associated in the GWAS and follow-up study and containing IL2 and IL21, and at 3q28 harboring LPP. In addition, we provide new evidence for an association, not previously reported, on 2q31 harboring a strong candidate gene, ITGA4. In conclusion, in this first follow-up study of celiac cases from the USA, we provide additional evidence that five of eight previously identified regions harbor risk alleles for celiac disease, and new evidence for an association on 2q31. The underlying functional mutations responsible for these replicated associations need to be identified.

Endogenous opioids modify dyspnoea during treadmill exercise in patients with COPD

Exogenous opioid drugs, such as morphine, relieve breathlessness. The present study hypothesis was that endogenous opioids, released during the stress of exercise, modify dyspnoea in patients with chronic obstructive pulmonary disease. After familiarisation, patients performed an incremental treadmill exercise test followed by constant work on the treadmill for 10 min. At subsequent visits (2 to 3 days apart), patients received two puffs of albuterol, had a catheter placed in an arm vein for removal of blood to measure beta-endorphin immunoreactivity, received normal saline or 10 mg of naloxone intravenously in randomised order, and then performed high-intensity constant work rate exercise on the treadmill. The mean+/-sd age of the 17 patients (eight females and nine males) was 63+/-7 yrs, and post-bronchodilator forced expiratory volume in one second was 50+/-17% predicted. In both conditions, beta-endorphin levels increased three-fold from rest to end-exercise. The regression slope of breathlessness as a function of oxygen consumption (primary outcome), mean ratings of breathlessness throughout exercise and peak ratings of breathlessness were significantly higher with naloxone than normal saline. There were no differences in physiological responses throughout exercise between conditions. In conclusion, endogenous opioids modify dyspnoea during treadmill exercise in patients with chronic obstructive pulmonary disease by apparent alteration of central perception.

Liver involvement in celiac disease

Celiac disease is a chronic immune-mediated disorder that may affect several organs. Liver abnormalities are common extraintestinal manifestations of celiac disease. Isolated hypertransaminasemia, with mild or nonspecific histologic changes in the liver biopsy, also known as ''celiac hepatitis'', is the most frequent presentation of liver injury in celiac disease. Both, histologic changes and liver enzymes reverse to normal after treatment with a gluten-free diet in most patients. Celiac disease may also be associated with severe forms of liver disease and/or coexist with other chronic liver disorders (i.e., autoimmune liver diseases). The mechanisms underlying liver injury in celiac disease are poorly understood. Predisposition to autoimmunity by shared genetic factors (i.e., human leukocyte antigen [HLA] genes) as well as the systemic effects of abnormal intestinal permeability, cytokines, autoantibodies, and/or other yet undefined biologic mediators induced by gluten exposure in susceptible persons may play a pathogenic role. The aims of this article are: 1) to review the spectrum of liver injury related to celiac disease and 2) to understand the clinical implications of celiac disease in patients with chronic liver disorders.

Perceptual and physiologic responses during treadmill and cycle exercise in patients with COPD

BACKGROUND

Although the cycle ergometer is the traditional mode for exercise testing in patients with respiratory disease, this preference over the treadmill does not consider perceptual responses. Our hypotheses were as follows: (1) the regression slope between breathlessness and oxygen consumption (Vo(2)) is greater on the treadmill than on the cycle ergometer; and (2) the regression slope between leg discomfort and Vo(2) is greater on the cycle ergometer than on the treadmill.

METHODS

Twenty patients (10 men/10 women) with COPD (mean +/- SD postbronchodilator FEV(1), 50 +/- 15% of predicted) used a continuous method to report changes in breathlessness and in leg discomfort during cycle and treadmill exercise.

RESULTS

Patients reported an earlier onset of breathlessness and leg discomfort during cycling. Peak ratings of breathlessness were higher on the treadmill, whereas peak ratings of leg discomfort were higher on the cycle ergometer. The regression slopes for breathlessness as a function of Vo(2) and of minute ventilation (Ve) were higher on the treadmill. The regression slopes between leg discomfort and Vo(2) were similar for treadmill and cycle exercise. Peak Vo(2) was significantly higher with treadmill exercise (mean Delta = 8%; p = 0.002).

CONCLUSIONS

Patients with COPD exhibit different perceptual and physiologic responses during treadmill walking and cycling. Although ratings of breathlessness are initially higher with cycling at equivalent levels of Vo(2), the changes in breathlessness as a function of physiologic stimuli (Vo(2) and Ve) are greater during treadmill exercise. Leg discomfort is the predominant symptom throughout cycling.

A novel partial 5HT3 agonist DDP733 after a standard refluxogenic meal reduces reflux events: a randomized, double-blind, placebo-controlled pharmacodynamic study

BACKGROUND

DDP733, a selective partial 5HT(3) receptor agonist, increases lower oesophageal sphincter pressure in experimental animal models. However, its effect on gastro-oesophageal reflux or lower oesophageal sphincter pressure in humans remains unknown.

AIM

To evaluate the effect of DDP733 on reflux episodes in healthy volunteers receiving a refluxogenic meal.

METHODS

A randomized, double-blind, placebo-controlled cross-over study evaluated the pharmacodynamic effects of DDP733 (0.5, 0.8 and 1.4 mg). Healthy subjects underwent oesophageal manometry and intra-oesophageal multichannel intraluminal impedance and pH after a refluxogenic meal.

RESULTS

DDP733 0.5 mg significantly (P = 0.013) reduced the rate of reflux episodes after a refluxogenic meal from 10 (+/-2.2) on placebo to 6 (+/-1.2) on drug over a 2-h period. DDP733 0.8 and 1.4 mg had no significant effect on reducing the number of reflux episodes. Significant differences in resting lower oesophageal sphincter pressure and the proportion of time pH was <4 (placebo minus drug) after a refluxogenic meal were not observed. No serious adverse events were reported.

CONCLUSION

In healthy subjects, the partial 5HT(3) agonist DDP733 at a dose of 0.5 mg significantly reduces the rate of reflux events, but did not result in a significant change in lower oesophageal sphincter pressure at 1 h postdosing.

Gliadin-dependent neuromuscular and epithelial secretory responses in gluten-sensitive HLA-DQ8 transgenic mice

Celiac disease is a gluten intolerance caused by a T-cell response against human leukocyte antigen (HLA)-DQ2 and DQ8-bound gluten peptides. Some subjects experience gastrointestinal symptoms in the absence of villous atrophy. Here we investigate the potential mechanisms of gut dysfunction in gluten-sensitive HLA-DQ8 transgenic mice. HLA-DQ8 mice were sensitized and gavaged with gliadin 3x/wk for 3 wk (G/G). Controls included 1) nonsensitized mice gavaged with rice (C); 2) gliadin-sensitized mice gavaged with rice (G/R); and 3) BSA-sensitized mice gavaged with BSA (BSA/BSA). CD3(+) intraepithelial lymphocyte, macrophage, and FOX-P3-positive cell counts were determined. Acetylcholine release, small intestinal contractility, and epithelial ion transport were measured. Gut function was investigated after gluten withdrawal and in HLA-DQ6 mice. Intestinal atrophy was not observed in G/G mice. Recruitment of intraepithelial lymphocyte, macrophages, and FOX-P3+ cells were observed in G/G, but not in C, G/R, or BSA/BSA mice. This was paralleled by increased acetylcholine release from the myenteric plexus, muscle hypercontractility, and increased active ion transport in G/G mice. Changes in muscle contractility normalized in DQ8 mice after a gluten withdrawal. HLA-DQ6 controls did not exhibit the abnormalities in gut function observed in DQ8 mice. Gluten sensitivity in HLA-DQ8 mice induces immune activation in the absence of intestinal atrophy. This is associated with cholinergic dysfunction and a prosecretory state that may lead to altered water movements and dysmotility. The results provide a mechanism by which gluten could induce gut dysfunction in patients with a genetic predisposition but without fully evolved celiac disease.

Mechanical ventilation in the management of acute respiratory distress syndrome

The occurrence of acute respiratory distress syndrome (ARDS), is now common in intensive care units throughout the world. The diagnosis of ARDS is based on a definition that includes bilateral pulmonary infiltrates on chest radiographs, impaired oxygenation, and the absence of clinical evidence of elevated left atrial pressure. ARDS is the clinical result of a group of diverse processes, which range from physical or chemical injury, to extensive activation of innate inflammatory response. All these processes damage the integrity of the alveolar-capillary barrier causing increased alveolar-capillary permeability and an influx of protein-rich fluid into the alveolar space. This alveolar flooding results in hypoxemia, inactivated surfactant, intrapulmonary shunt, and impaired alveolar ventilation. The treatment of acute respiratory distress syndrome is largely supportive in nature, keeping patients alive while allowing their lungs to heal, and minimizing further pulmonary insult. In 1994 the National Heart, Lung, and Blood Institute (NHLBI) established the ARDS Network for the conduct of clinical trials. This is a network, supported by the National Institutes of Health, that provided the infrastructure for well-designed, multicenter, randomized trials of therapies for ARDS. The first study from this group in 2001 produced landmark data demonstrating mortality improvements in ARDS with particular mechanical ventilation strategies. Specifically, low tidal volume mechanical ventilation was demonstrated to reduce mortality by 22%. Other strategies such as high positive end expiratory pressure and prone positioning have not been shown to reduce mortality. Clinicians who are involved in the care of patients with ARDS should have a basic understanding of mechanical ventilation and the evidence guiding the mechanical ventilation strategies of these patients. Until further evidence is published, providers should adopt the use of a volume and pressure limited approach to mechanical ventilation.

Utilising multichannel intraluminal impedance for diagnosing GERD: a review

The diagnosis of gastroesophageal reflux is sometimes challenging, especially when symptoms are unresponsive to high-dose acid suppression. With the advent of new technology it is possible to detect and quantify nonacid or weakly acidic reflux. Multichannel intraluminal impedance (MII), introduced over 10 years ago, is gaining popularity as a reflux detection tool. The ability to detect nonacid or weakly acidic reflux events, aerophagia, and to discern true reflux events from swallows could make it more a powerful tool than pH detection alone. This is a review of the role of MII as it pertains to the diagnosis of GERD and related disorders. Studies done on normal subjects and in GERD reveal that nonacid or weakly acidic reflux occurs frequently. Several studies have been published that document types and frequency or reflux episodes comparing pH to MII. pH electrodes fail to detect the majority of nonacid or weakly acidic reflux events. MII has revealed nonacid reflux to be less common in untreated GERD subjects than in normal subjects. GERD subjects have greater degrees of liquid-type reflux events compared to normal subjects who have more gas-type reflux events. In treated GERD subjects and normal subjects, proton pump inhibitors do not seem to decrease the amount of reflux but render the reflux nonacid or weakly acidic in nature. Recently work evaluating atypical symptoms of GERD with MII has been published.

Thrombotic Thrombocytopenic Purpura: aetiology, pathophysiology and treatment

Thrombotic thrombocytopenic purpura (TTP) is a rare disorder whose varied clinical manifestations result from the formation of platelet-rich thrombi within the microvasculature and consequent tissue ischaemia. This review will outline how, in the eighty years since its initial description, scientific discoveries have not only led to a deeper understanding of the fundamental pathophysiology of TTP, but have also contributed to advances in the clinical management of this condition. Current research in this field will hopefully provide the basis for the design and development of novel therapeutic strategies.