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1.
Poor Sensitivity of Fecal Gluten Immunogenic Peptides and Serum Antibodies to Detect Duodenal Mucosal Damage in Celiac Disease Monitoring.
Laserna-Mendieta, EJ, Casanova, MJ, Arias, Á, Arias-González, L, Majano, P, Mate, LA, Gordillo-Vélez, CH, Jiménez, M, Angueira, T, Tébar-Romero, E, et al
Nutrients. 2020;(1)
Abstract
A lifelong gluten-free diet (GFD) is the only current treatment for celiac disease (CD), but strict compliance is complicated. Duodenal biopsies are the "gold standard" method for diagnosing CD, but they are not generally recommended for disease monitoring. We evaluated the sensitivity and specificity of fecal gluten immunogenic peptides (GIPs) to detect duodenal lesions in CD patients on a GFD and compared them with serum anti-tissue transglutaminase (tTG) IgA antibodies. A prospective study was conducted at two tertiary centers in Spain on a consecutive series of adolescents and adults with CD who maintained a long-lasting GFD. Adherence to a GFD and health-related quality of life were scored with validated questionnaires. Mucosal damage graded according to the Marsh-Oberhüber classification (Marsh 1/2/3) was used as the reference standard. Of the 97 patients included, 27 presented duodenal mucosal damage and 70 had normal biopsies (Marsh 0). The sensitivity (33%) and specificity (81%) of GIPs were similar to those provided by the two assays used to measure anti-tTG antibodies. Scores in questionnaires showed no association with GIP, but an association between GIPs and patients' self-reported gluten consumption was found (p = 0.003). GIP displayed low sensitivity but acceptable specificity for the detection of mucosal damage in CD.
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2.
Mucosal vitamin D signaling in inflammatory bowel disease.
Kellermann, L, Jensen, KB, Bergenheim, F, Gubatan, J, Chou, ND, Moss, A, Nielsen, OH
Autoimmunity reviews. 2020;(11):102672
Abstract
Epidemiological studies have identified vitamin D (25(OH)D) deficiency to be highly prevalent among patients with inflammatory bowel disease (IBD), and low serum levels correlate with a higher disease activity and a more complicated disease course. The link to IBD pathogenesis has been subject of investigations, primarily due to the distinct immunological functions of vitamin D signaling, including anti-inflammatory and anti-fibrotic actions. Vitamin D is a pleiotropic hormone that executes its actions on cells through the vitamin D receptor (VDR). A leaky gut, i.e. an insufficient intestinal epithelial barrier, is thought to be central for the pathogenesis of IBD, and emerging data support the concept that vitamin D/VDR signaling in intestinal epithelial cells (IECs) has an important role in controlling barrier integrity. Here we review the latest evidence on how vitamin D promotes the interplay between IECs, the gut microbiome, and immune cells and thereby regulate the intestinal immune response. On the cellular level, vitamin D signaling regulates tight junctional complexes, apoptosis, and autophagy, leading to increased epithelial barrier integrity, and promotes expression of antimicrobial peptides as part of its immunomodulating functions. Further, intestinal VDR expression is inversely correlated with the severity of inflammation in patients with IBD, which might compromise the positive effects of vitamin D signaling in patients with flaring disease. Efforts to reveal the role of vitamin D in the pathophysiology of IBD will pave the road for the invention of more rational treatment strategies of this debilitating disease in the future.
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A Guide to Human Zinc Absorption: General Overview and Recent Advances of In Vitro Intestinal Models.
Maares, M, Haase, H
Nutrients. 2020;(3)
Abstract
Zinc absorption in the small intestine is one of the main mechanisms regulating the systemic homeostasis of this essential trace element. This review summarizes the key aspects of human zinc homeostasis and distribution. In particular, current knowledge on human intestinal zinc absorption and the influence of diet-derived factors on bioaccessibility and bioavailability as well as intrinsic luminal and basolateral factors with an impact on zinc uptake are discussed. Their investigation is increasingly performed using in vitro cellular intestinal models, which are continually being refined and keep gaining importance for studying zinc uptake and transport via the human intestinal epithelium. The vast majority of these models is based on the human intestinal cell line Caco-2 in combination with other relevant components of the intestinal epithelium, such as mucin-secreting goblet cells and in vitro digestion models, and applying improved compositions of apical and basolateral media to mimic the in vivo situation as closely as possible. Particular emphasis is placed on summarizing previous applications as well as key results of these models, comparing their results to data obtained in humans, and discussing their advantages and limitations.
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Zonulin-Dependent Intestinal Permeability in Children Diagnosed with Mental Disorders: A Systematic Review and Meta-Analysis.
Asbjornsdottir, B, Snorradottir, H, Andresdottir, E, Fasano, A, Lauth, B, Gudmundsson, LS, Gottfredsson, M, Halldorsson, TI, Birgisdottir, BE
Nutrients. 2020;(7)
Abstract
Worldwide, up to 20% of children and adolescents experience mental disorders, which are the leading cause of disability in young people. Research shows that serum zonulin levels are associated with increased intestinal permeability (IP), affecting neural, hormonal, and immunological pathways. This systematic review and meta-analysis aimed to summarize evidence from observational studies on IP in children diagnosed with mental disorders. The review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic search of the Cochrane Library, PsycINFO, PubMed, and the Web of Science identified 833 records. Only non-intervention (i.e., observational) studies in children (<18 years) diagnosed with mental disorders, including a relevant marker of intestinal permeability, were included. Five studies were selected, with the risk of bias assessed according to the Newcastle-Ottawa scale (NOS). Four articles were identified as strong and one as moderate, representing altogether 402 participants providing evidence on IP in children diagnosed with attention deficit and hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and obsessive-compulsive disorder (OCD). In ADHD, elevated serum zonulin levels were associated with impaired social functioning compared to controls. Children with ASD may be predisposed to impair intestinal barrier function, which may contribute to their symptoms and clinical outcome compared to controls. Children with ASD, who experience gastro-intestinal (GI) symptoms, seem to have an imbalance in their immune response. However, in children with OCD, serum zonulin levels were not significantly different compared to controls, but serum claudin-5, a transmembrane tight-junction protein, was significantly higher. A meta-analysis of mean zonulin plasma levels of patients and control groups revealed a significant difference between groups (p = 0.001), including the four studies evaluating the full spectrum of the zonulin peptide family. Therefore, further studies are required to better understand the complex role of barrier function, i.e., intestinal and blood-brain barrier, and of inflammation, to the pathophysiology in mental and neurodevelopmental disorders. This review was PROSPERO preregistered, (162208).
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5.
Molecular Physiology and Pathophysiology of Bilirubin Handling by the Blood, Liver, Intestine, and Brain in the Newborn.
Hansen, TWR, Wong, RJ, Stevenson, DK
Physiological reviews. 2020;(3):1291-1346
Abstract
Bilirubin is the end product of heme catabolism formed during a process that involves oxidation-reduction reactions and conserves iron body stores. Unconjugated hyperbilirubinemia is common in newborn infants, but rare later in life. The basic physiology of bilirubin metabolism, such as production, transport, and excretion, has been well described. However, in the neonate, numerous variables related to nutrition, ethnicity, and genetic variants at several metabolic steps may be superimposed on the normal physiological hyperbilirubinemia that occurs in the first week of life and results in bilirubin levels that may be toxic to the brain. Bilirubin exists in several isomeric forms that differ in their polarities and is considered a physiologically important antioxidant. Here we review the chemistry of the bilirubin molecule and its metabolism in the body with a particular focus on the processes that impact the newborn infant, and how differences relative to older children and adults contribute to the risk of developing both acute and long-term neurological sequelae in the newborn infant. The final section deals with the interplay between the brain and bilirubin and its entry, clearance, and accumulation. We conclude with a discussion of the current state of knowledge regarding the mechanism(s) of bilirubin neurotoxicity.
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6.
Increased Intestinal Permeability in Older Subjects Impacts the Beneficial Effects of Dietary Polyphenols by Modulating Their Bioavailability.
Hidalgo-Liberona, N, González-Domínguez, R, Vegas, E, Riso, P, Del Bo', C, Bernardi, S, Peron, G, Guglielmetti, S, Gargari, G, Kroon, PA, et al
Journal of agricultural and food chemistry. 2020;(44):12476-12484
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Abstract
Polyphenols have great potential in regulating intestinal health and ameliorating pathological conditions related to increased intestinal permeability (IP). However, the efficacy of dietary interventions with these phytochemicals may significantly be influenced by interindividual variability factors affecting their bioavailability and consequent biological activity. In the present study, urine samples collected from older subjects undergoing a crossover intervention trial with polyphenol-rich foods were subjected to metabolomics analysis for investigating the impact of increased IP on the bioavailability of polyphenols. Interestingly, urinary levels of phase II and microbiota-derived metabolites were significantly different between subjects with healthier intestinal barrier integrity and those with increased IP disruption. Our results support that this IP-dependent impaired bioavailability of polyphenols could be attributed to disturbances in the gut microbial metabolism and phase II methylation processes. Furthermore, we also observed that microbiota-derived metabolites could be largely responsible for the biological activity elicited by dietary polyphenols against age-related disrupted IP.
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Endoscopic duodenal mucosal resurfacing for the treatment of type 2 diabetes mellitus: one year results from the first international, open-label, prospective, multicentre study.
van Baar, ACG, Holleman, F, Crenier, L, Haidry, R, Magee, C, Hopkins, D, Rodriguez Grunert, L, Galvao Neto, M, Vignolo, P, Hayee, B, et al
Gut. 2020;(2):295-303
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Abstract
BACKGROUND The duodenum has become a metabolic treatment target through bariatric surgery learnings and the specific observation that bypassing, excluding or altering duodenal nutrient exposure elicits favourable metabolic changes. Duodenal mucosal resurfacing (DMR) is a novel endoscopic procedure that has been shown to improve glycaemic control in people with type 2 diabetes mellitus (T2D) irrespective of body mass index (BMI) changes. DMR involves catheter-based circumferential mucosal lifting followed by hydrothermal ablation of duodenal mucosa. This multicentre study evaluates safety and feasibility of DMR and its effect on glycaemia at 24 weeks and 12 months. METHODS International multicentre, open-label study. Patients (BMI 24-40) with T2D (HbA1c 59-86 mmol/mol (7.5%-10.0%)) on stable oral glucose-lowering medication underwent DMR. Glucose-lowering medication was kept stable for at least 24 weeks post DMR. During follow-up, HbA1c, fasting plasma glucose (FPG), weight, hepatic transaminases, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), adverse events (AEs) and treatment satisfaction were determined and analysed using repeated measures analysis of variance with Bonferroni correction. RESULTS Forty-six patients were included of whom 37 (80%) underwent complete DMR and 36 were finally analysed; in remaining patients, mainly technical issues were observed. Twenty-four patients had at least one AE (52%) related to DMR. Of these, 81% were mild. One SAE and no unanticipated AEs were reported. Twenty-four weeks post DMR (n=36), HbA1c (-10±2 mmol/mol (-0.9%±0.2%), p<0.001), FPG (-1.7±0.5 mmol/L, p<0.001) and HOMA-IR improved (-2.9±1.1, p<0.001), weight was modestly reduced (-2.5±0.6 kg, p<0.001) and hepatic transaminase levels decreased. Effects were sustained at 12 months. Change in HbA1c did not correlate with modest weight loss. Diabetes treatment satisfaction scores improved significantly. CONCLUSIONS In this multicentre study, DMR was found to be a feasible and safe endoscopic procedure that elicited durable glycaemic improvement in suboptimally controlled T2D patients using oral glucose-lowering medication irrespective of weight loss. Effects on the liver are examined further. TRIAL REGISTRATION NUMBER NCT02413567.
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Serum IL-21 levels from celiac disease patients correlates with anti-tTG IgA autoantibodies and mucosal damage.
Iervasi, E, Auricchio, R, Strangio, A, Greco, L, Saverino, D
Autoimmunity. 2020;(4):225-230
Abstract
Objectives: Coeliac disease is a multifactorial disorder influenced by environmental, genetic and immunological factors. Interleukin (IL)-21 has been linked to an increase disease risk and the serum level of IL-21 seems to be increased in CD compared to a healthy control population.Methods: Sera were collected from 160 CD patients, 120 untreated and 40 following a gluten-free diet, and form 45 healthy subjects. Serum IL-21 was evaluated by specific ELISA tests.Results: Our data show that patients with untreated CD display IL-21 concentrations significantly higher than both treated-CD patients (following a gluten-free diet) and controls. In addition, serum IL-21 correlates with serum titres of anti-tTG IgA autoantibodies. Finally, our results show a correlation of this cytokine with duodenal mucosal damage.Conclusions: A role of gluten, as antigen with stimulatory function on IL-21 production, seems to be confirmed by the longitudinal analyses showing that the gluten-free diet decreases to a nearly undetectable amount this cytokine. In addition, the finding of a positive correlation between the serum amount of IL-21 and the grade of duodenal mucosa damage suggests a strong immunomodulatory effect of this cytokine on cytotoxic T lymphocyte functions. This study provides an extra evidence to emerging data on the potential role IL-21 in CD pathogenesis, suggesting its involvement in the development and progression of CD. Significance statement: In untreated CD, serum IL-21 shows higher levels compared with treated CD and healthy subjects. Serum amounts of IL-21 correlate with anti-tTG IgA autoantibodies and with duodenal mucosa damage.
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Using Volatile Organic Compounds to Investigate the Effect of Oral Iron Supplementation on the Human Intestinal Metabolome.
Ahmed, A, Slater, R, Lewis, S, Probert, C
Molecules (Basel, Switzerland). 2020;(21)
Abstract
Patients with iron deficiency anaemia are treated with oral iron supplementation, which is known to cause gastrointestinal side effects by likely interacting with the gut microbiome. To better study this impact on the microbiome, we investigated oral iron-driven changes in volatile organic compounds (VOCs) in the faecal metabolome. Stool samples from patients with iron deficiency anaemia were collected pre- and post-treatment (n = 45 and 32, respectively). Faecal headspace gas analysis was performed by gas chromatography-mass spectrometry and the changes in VOCs determined. We found that the abundance of short-chain fatty acids and esters fell, while aldehydes increased, after treatment. These changes in pre- vs. post-iron VOCs resemble those reported when the gut is inflamed. Our study shows that iron changes the intestinal metabolome, we suggest by altering the structure of the gut microbial community.
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Dairy products influence gut hormone secretion and appetite differently: A randomized controlled crossover trial.
Hansson, P, Holven, KB, Øyri, LKL, Brekke, HK, Gjevestad, GO, Rehfeld, JF, Raza, GS, Herzig, KH, Ulven, SM
Journal of dairy science. 2020;(2):1100-1109
Abstract
Little is known about how dairy products with different nutrient contents and food matrices affect appetite sensation and gut hormone secretion. The objective of this study was to investigate how appetite sensation and gut hormone secretion in healthy adults are affected by meals with the same amount of fat but from different dairy products. Forty-seven healthy adults (70% women) were recruited to a randomized controlled crossover study with 4 dairy meals consisting of butter, cheese, whipped cream, or sour cream, corresponding to 45 g (approximately 60 energy percent) of fat. Plasma samples were collected for analysis of cholecystokinin (CCK), pancreatic polypeptide (PP), peptide YY (PYY), and ghrelin concentrations at 0, 2, 4, and 6 h after the meals and analyzed as the incremental area under the curve (iAUC0-6h) in a mixed model. Hunger, satiety, and appetite sensations were measured with a visual analog scale (VAS) immediately after finishing the meals and at 4 and 6 h postprandially. Intake of cheese induced a higher level of plasma PP-iAUC0-6h compared with butter or whipped cream, and a higher level of plasma CCK-iAUC0-6h compared with whipped cream. Intake of whipped cream increased VAS appetite at 4 h compared with cheese or sour cream, and at 6 h compared with cheese or butter. No significant meal effect was found for hunger, satiety, plasma PYY, or plasma ghrelin concentration. Intake of cheese increased postprandial plasma PP and CCK concentrations and decreased appetite compared with whipped cream but not with sour cream. These findings encourage further investigations of how different dairy products affect gut hormone secretion and appetite sensation.