Mutational spectrum of CFTR in cystic fibrosis patients with gastrointestinal and hepatobiliary manifestations

BACKGROUND

Cystic fibrosis (CF) is a rare and debilitating autosomal recessive disorder. It hampers the normal function of various organs and causes severe damage to the lungs, and digestive system leading to recurring pneumonia. Cf also affects reproductive health eventually may cause infertility. The disease manifests due to genetic aberrations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. This study aimed to screen for CFTR gene variants in Pakistani CF patients representing variable phenotypes.

METHODS

Clinical exome and Sanger sequencing were performed after clinical characterization of 25 suspected cases of CF (CF1-CF25). ACMG guidelines were followed to interpret the clinical significance of the identified variants.

RESULTS

Clinical investigations revealed common phenotypes such as pancreatic insufficiency, chest infections, chronic liver and lung diseases. Some patients also displayed symptoms like gastroesophageal reflux disease (GERD), neonatal cholestasis, acrodermatitis, diabetes mellitus, and abnormal malabsorptive stools. Genetic analysis of the 25 CF patients identified deleterious variants in the CFTR gene. Notably, 12% of patients showed compound heterozygous variants, while 88% had homozygous variants. The most prevalent variant was p. (Met1Thr or Met1?) at 24%, previously not reported in the Pakistani population. The second most common variant was p. (Phe508del) at 16%. Other variants, including p. (Leu218*), p. (Tyr569Asp), p. (Glu585Ter), and p. (Arg1162*) were also identified in the present study. Genetic analysis of one of the present patients showed a pathogenic variant in G6PD in addition to CFTR.

CONCLUSION

The study reports novel and reported variants in the CFTR gene in CF patients in Pakistani population having distinct phenotypes. It also emphasizes screening suspected Pakistani CF patients for the p. (Met1Thr) variant because of its increased observance and prevalence in the study. Moreover, the findings also signify searching for additional pathogenic variants in the genome of CF patients, which may modify the phenotypes. The findings contribute valuable information for the diagnosis, genetic counseling, and potential therapeutic strategies for CF patients in Pakistan.

Shared genetic influences between eating disorders and gastrointestinal disease in a large, population-based sample of adult women and men

BACKGROUND

Some preliminary research suggests higher rates of gastrointestinal disease in individuals with eating disorders (EDs). However, research is limited, and it remains unknown what etiologic factors account for observed associations. This was the first study to examine how EDs and dimensional ED symptoms (e.g. body dissatisfaction, binge eating) are phenotypically and etiologically associated with gastrointestinal disease in a large, population-based twin sample.

METHODS

Adult female (N = 2980) and male (N = 2903) twins from the Michigan State University Twin Registry reported whether they had a lifetime ED (anorexia nervosa, bulimia nervosa, or binge-eating disorder) and completed a measure of dimensional ED symptoms. We coded the presence/absence of lifetime gastrointestinal disease (e.g. inflammatory bowel disease) based on responses to questions regarding chronic illnesses and medications. We first examined whether twins with gastrointestinal disease had higher rates of EDs and ED symptoms, then used correlated factors twin models to investigate genetic and environmental contributions to the overlap between disorders.

RESULTS

Twins with gastrointestinal disease had significantly greater dimensional ED symptoms (β = 0.21, p < 0.001) and odds of a lifetime ED (OR 2.90, p = 0.001), regardless of sex. Shared genetic factors fully accounted for the overlap between disorders, with no significant sex differences in etiologic associations.

CONCLUSIONS

Comorbidity between EDs and gastrointestinal disease may be explained by overlap in genetic influences, potentially including inflammatory genes implicated in both types of disorders. Screening for gastrointestinal disease in people with EDs, and EDs in those with gastrointestinal disease, is warranted.

Genetic liability for gastrointestinal inflammation disorders and association with gastrointestinal symptoms in children with and without autism

Children with autism spectrum disorder (ASD) have a greater prevalence of gastrointestinal (GI) symptoms than children without ASD. We tested whether polygenic scores for each of three GI disorders (ulcerative colitis, inflammatory bowel disease, and Crohn's disease) were related to GI symptoms in children with and without ASD. Using genotyping data (564 ASD cases and 715 controls) and external genome-wide association study summary statistics, we computed GI polygenic scores for ulcerative colitis (UC-PGS), inflammatory bowel disease (IDB-PGS), and Crohn's disease (CD-PGS). Multivariable logistic regression models, adjusted for genetic ancestry, were used to estimate associations between each GI-PGS and (1) ASD case-control status, and (2) specific GI symptoms in neurotypical children and separately in ASD children. In children without ASD, polygenic scores for ulcerative colitis were significantly associated with experiencing any GI symptom (adjusted odds ratio (aOR) = 1.36, 95% confidence interval (CI) = 1.03-1.81, p = 0.03) and diarrhea specifically (aOR = 5.35, 95% CI = 1.77-26.20, p = 0.01). Among children without ASD, IBD-PGS, and Crohn's PGS were significantly associated with diarrhea (aOR = 3.55, 95% CI = 1.25-12.34, p = 0.02) and loose stools alternating with constipation (aOR = 2.57, 95% CI = 1.13-6.55, p = 0.03), respectively. However, the three PGS were not associated with GI symptoms in the ASD case group. Furthermore, polygenic scores for ulcerative colitis significantly interacted with ASD status on presentation of any GI symptom within a European ancestry subset (aOR = 0.42, 95% CI = 0.19-0.88, p = 0.02). Genetic risk factors for some GI symptoms differ between children with and without ASD. Furthermore, our finding that increased genetic risks for GI inflammatory disorders are associated with GI symptoms in children without ASD informs future work on the early detection of GI disorders.

Association between gut microbiota and seven gastrointestinal diseases: A Mendelian randomized study

BACKGROUND

Observational research has shed light on the ability of gut microbes to influence the onset and progression of gastrointestinal diseases. The causal relationships between specific gut microbiomes and various gastrointestinal conditions, however, remain unknown.

METHODS

We investigated the relationship between gut microbiota and seven specific gastrointestinal disorders using a robust two-sample Mendelian randomization (MR) approach. The inverse variance-weighted (IVW) method was used as the primary analysis tool in our study. Furthermore, we conducted multiple sensitivity analyses to strengthen the robustness of our findings and ensure the reliability of the IVW method.

RESULTS

Our research has discovered significant links between the composition of gut microbiota and a variety of gastrointestinal ailments. We found compelling links between 13 gut microbiota and fatty liver, four gut microbiota and cirrhosis, eight gut microbiota and hepatocellular carcinoma, four gut microbiota and cholelithiasis, 12 gut microbiota and acute pancreatitis, eight gut microbiota and chronic pancreatitis, and 11 gut microbiota and pancreatic cancer. These findings shed light on the intricate relationship between gut microbes and the emergence of these specific gastrointestinal conditions.

CONCLUSIONS

The findings of this extensive study not only validate the potential role of specific gut microbiota in gastrointestinal diseases, but also fill a critical gap in previous research. The discovery of these specific gut microbiota is a significant step forward because they may serve as novel and promising biomarkers for both the prevention and treatment of gastrointestinal conditions.

Exploration of the causal effects of leukocyte telomere length and four gastrointestinal diseases: a two-sample bidirectional Mendelian randomization study

BACKGROUND

To explore the underlying causality between leukocyte telomere length (LTL) and four gastrointestinal diseases, we designed a two-sample bidirectional Mendelian randomization study.

METHODS

Two-sample Mendelian randomization (MR) was used to explore genetic causality between LTL and four gastrointestinal diseases, including irritable bowel syndrome (IBS), gastroesophageal reflux disease (GERD), gastrointestinal ulcers disease (GUD), and nonalcoholic fatty liver disease (NAFLD). We utilized inverse-variance weighted (IVW) as the primary method for MR analysis. Supplementary analyses were conducted using methods such as MR-Egger regression, weighted-median, Maximum Likelihood (MaxLik), Robust adjusted profile score (MR-RAPS), Contamination mixture (ConMix), and MR-mix. Cochran's Q was calculated to check for heterogeneity. The MR-Egger regression and MR pleiotropy residual sum and outlier (MR-PRESSO) were detected for pleiotropy.

RESULTS

The IVW analysis suggests that there may be a potential causal relationship between LTL and two diseases (odds ratio (OR): 1.062; 95% confidence interval (CI): 1.003, 1.124; p = 0.038 for IBS and OR: 0.889; 95% CI: 0.798, 0.990; p = 0.032 for GERD). However, other methods do not entirely align with the results of the IVW analysis. In the reverse MR analysis, we did not find statistically significant associations between LTL and these four diseases.

CONCLUSION

The current evidence does not definitively rule out a causal relationship between LTL and these four gastrointestinal diseases but suggests a potential association between LTL and IBS, or LTL and GERD. Exploring the relationship between gastrointestinal diseases and LTL may offer new insights into the onset, progression, and treatment of these diseases.

Genetic and observational associations of lung function with gastrointestinal tract diseases: pleiotropic and mendelian randomization analysis

BACKGROUND

The two-way communications along the gut-lung axis influence the immune function in both gut and lung. However, the shared genetic characteristics of lung function with gastrointestinal tract (GIT) diseases remain to be investigated.

METHODS

We first investigated the genetic correlations between three lung function traits and four GIT diseases. Second, we illustrated the genetic overlap by genome-wide pleiotropic analysis (PLACO) and further pinpointed the relevant tissue and cell types by partitioning heritability. Furthermore, we proposed pleiotropic genes as potential drug targets by drug database mining. Finally, we evaluated the causal relationships by epidemiologic observational study and Mendelian randomization (MR) analysis.

RESULTS

We found lung function and GIT diseases were genetically correlated. We identified 258 pleiotropic loci, which were enriched in gut- and lung-specific regions marked by H3K4me1. Among these, 16 pleiotropic genes were targets of drugs, such as tofacitinib and baricitinib targeting TYK2 for the treatment of ulcer colitis and COVID-19, respectively. We identified a missense variant in TYK2, exhibiting a shared causal effect on FEV1/FVC and inflammatory bowel disease (rs12720356, PPLACO=1.38 × 10- 8). These findings suggested TYK2 as a promising drug target. Although the epidemiologic observational study suggested the protective role of lung function in the development of GIT diseases, no causalities were found by MR analysis.

CONCLUSIONS

Our study suggested the shared genetic characteristics between lung function and GIT diseases. The pleiotropic variants could exert their effects by modulating gene expression marked by histone modifications. Finally, we highlighted the potential of pleiotropic analyses in drug repurposing.

Evidence of shared genetic factors in the etiology of gastrointestinal disorders and endometriosis and clinical implications for disease management

In clinical practice, the co-existence of endometriosis and gastrointestinal symptoms is often observed. Using large-scale datasets, we report a genetic correlation between endometriosis and irritable bowel syndrome (IBS), peptic ulcer disease (PUD), gastro-esophageal reflux disease (GORD), and a combined GORD/PUD medicated (GPM) phenotype. Mendelian randomization analyses support a causal relationship between genetic predisposition to endometriosis and IBS and GPM. Identification of shared risk loci highlights biological pathways that may contribute to the pathogenesis of both diseases, including estrogen regulation and inflammation, and potential therapeutic drug targets (CCKBR; PDE4B). Higher use of IBS, GORD, and PUD medications in women with endometriosis and higher use of hormone therapies in women with IBS, GORD, and PUD, support the co-occurrence of these conditions and highlight the potential for drug repositioning and drug contraindications. Our results provide evidence of shared disease etiology and have important clinical implications for diagnostic and treatment decisions for both diseases.

Genetic analysis confirms a link between gastrointestinal disorders and endometriosis

Patients with endometriosis often report gastrointestinal symptoms in addition to those usually considered hallmarks of the disorder (pain and infertility). Yang et al.1 identify genetic risk factors that can contribute to a shared disease etiology, providing new opportunities for improvements in disease management.

Assessing causality between osteoarthritis and gastrointestinal disorders: a Mendelian randomization study

The association between osteoarthritis (OA) and gastrointestinal disorders was found in observational studies. However, the causality is still elusive. A bidirectional Mendelian randomization (MR) analysis using genome wide association studies data was conducted to assess the causal association between OA and gastrointestinal diseases [including peptic ulcer disease (PUD), gastroesophageal reflux disease (GORD), and inflammatory bowel disease (IBD)]. A two-step MR (TSMR) was conducted between OA, gastrointestinal diseases and drugs to explore the mediating effects of non-steroidal anti-inflammatory drugs (NSAIDs) and opioids use. We used multivariable MR (MVMR) analysis to further validate the impact of prescription history on diseases. Results had statistical significance at a Bonferroni corrected P-value below 0.008. We observed that genetically predicted OA had a significant positive association with GORD [odds ratio (OR) = 1.26, P = 5e-05], but not with PUD or IBD. Regarding the other direction, gastrointestinal disorders as exposure had a null association with OA. Using TSMR, OA patients tended to increase the use of NSAIDs (OR = 1.45, P = 0.001) and opioids (OR = 1.77, P = 2e-05), but only the use of opioids increased the risk of GORD (OR = 1.43, P = 5e-09). Further MVMR analysis showed that the adverse effect of OA on GORD was significantly reduced after adjusting for opioids use (OR = 1.20, P = 0.038). This study provides evidence for the causal association between OA and increased risk of GORD, which is partly attributed to opioids use in OA patients but not NSAIDs.

Depression and risk of gastrointestinal disorders: a comprehensive two-sample Mendelian randomization study of European ancestry

BACKGROUND

Major depressive disorder (MDD) is clinically documented to co-occur with multiple gastrointestinal disorders (GID), but the potential causal relationship between them remains unclear. We aimed to evaluate the potential causal relationship of MDD with 4 GID [gastroesophageal reflux disease (GERD), irritable bowel syndrome (IBS), peptic ulcer disease (PUD), and non-alcoholic fatty liver disease (NAFLD)] using a two-sample Mendelian randomization (MR) design.

METHODS

We obtained genome-wide association data for MDD from a meta-analysis (N = 480 359), and for GID from the UK Biobank (N ranges: 332 601-486 601) and FinnGen (N ranges: 187 028-218 792) among individuals of European ancestry. Our primary method was inverse-variance weighted (IVW) MR, with a series of sensitivity analyses to test the hypothesis of MR. Individual study estimates were pooled using fixed-effect meta-analysis.

RESULTS

Meta-analyses IVW MR found evidence that genetically predicted MDD may increase the risk of GERD, IBS, PUD and NAFLD. Additionally, reverse MR found evidence of genetically predicted GERD or IBS may increase the risk of MDD.

CONCLUSIONS

Genetically predicted MDD may increase the risk of GERD, IBS, PUD and NAFLD. Genetically predicted GERD or IBS may increase the risk of MDD. The findings may help elucidate the mechanisms underlying the co-morbidity of MDD and GID. Focusing on GID symptoms in patients with MDD and emotional problems in patients with GID is important for the clinical management.

Mechanosensing Piezo channels in gastrointestinal disorders

All cells in the body are exposed to physical force in the form of tension, compression, gravity, shear stress, or pressure. Cells convert these mechanical cues into intracellular biochemical signals; this process is an inherent property of all cells and is essential for numerous cellular functions. A cell's ability to respond to force largely depends on the array of mechanical ion channels expressed on the cell surface. Altered mechanosensing impairs conscious senses, such as touch and hearing, and unconscious senses, like blood pressure regulation and gastrointestinal (GI) activity. The GI tract's ability to sense pressure changes and mechanical force is essential for regulating motility, but it also underlies pain originating in the GI tract. Recent identification of the mechanically activated ion channels Piezo1 and Piezo2 in the gut and the effects of abnormal ion channel regulation on cellular function indicate that these channels may play a pathogenic role in disease. Here, we discuss our current understanding of mechanically activated Piezo channels in the pathogenesis of pancreatic and GI diseases, including pancreatitis, diabetes mellitus, irritable bowel syndrome, GI tumors, and inflammatory bowel disease. We also describe how Piezo channels could be important targets for treating GI diseases.

Birth weight, childhood obesity, adulthood obesity and body composition, and gastrointestinal diseases: a Mendelian randomization study

OBJECTIVE

This Mendelian randomization study aimed to investigate the associations of birth weight, childhood BMI, and adulthood BMI, waist-hip ratio, and body composition with the risk of 24 gastrointestinal diseases.

METHODS

Independent genetic instruments associated with the exposures at the genome-wide significance level (p < 5 × 10-8 ) were selected from corresponding large-scale genome-wide association studies. Summary-level data for gastrointestinal diseases were obtained from the UK Biobank, the FinnGen study, and large consortia of European ancestry.

RESULTS

Genetically predicted higher levels of birth weight were associated with a lower risk of gastroesophageal reflux. Genetically predicted higher childhood BMI was associated with an increased risk of duodenal ulcer, nonalcoholic fatty liver disease, and cholelithiasis. However, the associations did not persist after adjusting for genetically predicted adulthood BMI. Genetically predicted higher adulthood BMI and waist-hip ratio were associated with 19 and 17 gastrointestinal diseases, respectively. Genetically predicted greater visceral adiposity was associated with an increased risk of 17 gastrointestinal diseases. There were no strong associations among genetically predicted whole-body fat and fat-free mass indices with gastrointestinal diseases.

CONCLUSIONS

This study suggests that greater adulthood adiposity, measured as either BMI, waist-hip ratio, or visceral adipose tissue, is causally associated with an increased risk of a broad range of gastrointestinal diseases in the European population.

Distinctive gastrointestinal motor dysfunction in patients with MNGIE

BACKGROUND

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare mitochondrial disease caused by mutations in TYMP, encoding thymidine phosphorylase. Clinically it is characterized by severe gastrointestinal dysmotility associated with cachexia and a demyelinating sensorimotor polyneuropathy. Even though digestive manifestations are progressive and invariably lead to death, the features of gastrointestinal motor dysfunction have not been systematically evaluated. The objective of this study was to describe gastrointestinal motor dysfunction in MNGIE using state-of-the art techniques and to evaluate the relationship between motor abnormalities and symptoms.

METHODS

Prospective study evaluating gastrointestinal motor function and digestive symptoms in all patients with MNGIE attended at a national referral center in Spain between January 2018 and July 2022.

KEY RESULTS

In this period, five patients diagnosed of MNGIE (age range 16-46 years, four men) were evaluated. Esophageal motility by high-resolution manometry was abnormal in four patients (two hypoperistalsis, two aperistalsis). Gastric emptying by scintigraphy was mildly delayed in four and indicative of gastroparesis in one. In all patients, small bowel high-resolution manometry exhibited a common, distinctive dysmotility pattern, characterized by repetitive bursts of spasmodic contractions, without traces of normal fasting and postprandial motility patterns. Interestingly, objective motor dysfunctions were detected in the absence of severe digestive symptoms.

CONCLUSIONS AND INFERENCES

MNGIE patients exhibit a characteristic motor dysfunction, particularly of the small bowel, even in patients with mild digestive symptoms and in the absence of morphological signs of intestinal failure. Since symptoms are not predictive of objective findings, early investigation is indicated.

Systematic analyses of GWAS summary statistics from UK Biobank identified novel susceptibility loci and genes for upper gastrointestinal diseases

In recent decades, upper gastrointestinal (GI) diseases have been highly prevalent worldwide. Although genome-wide association studies (GWASs) have identified thousands of susceptibility loci, only a few of them were conducted for chronic upper GI disorders, and most of them were underpowered and with small sample sizes. Additionally, for the known loci, only a tiny fraction of heritability can be explained and the underlying mechanisms and related genes remain unclear. In this study, we conducted a multi-trait analysis by the MTAG software and a two-stage transcriptome-wide association study (TWAS) with UTMOST and FUSION for seven upper GI diseases (oesophagitis, gastro-oesophageal reflux disease, other diseases of oesophagus, gastric ulcer, duodenal ulcer, gastritis and duodenitis and other diseases of stomach and duodenum) based on summary GWAS statistics from UK Biobank. In the MTAG analysis, we identified 7 loci associated with these upper GI diseases, including 3 novel ones at 4p12 (rs10029980), 12q13.13 (rs4759317) and 18p11.32 (rs4797954). In the TWAS analysis, we revealed 5 susceptibility genes in known loci and identified 12 novel potential susceptibility genes, including HOXC9 at 12q13.13. Further functional annotations and colocalization analysis indicated that rs4759317 (A>G) driven the association for GWAS signals and expression quantitative trait loci (eQTL) simultaneously at 12q13.13. The identified variant acted by decreasing the expression of HOXC9 to affect the risk of gastro-oesophageal reflux disease. This study provided insights into the genetic nature of upper GI diseases.

Gastrointestinal Dysfunction in Genetically Defined Neurodevelopmental Disorders

Gastrointestinal symptoms are common in most forms of neurodevelopment disorders (NDDs) such as in autism spectrum disorders (ASD). The current patient-reported outcome measures with validated questionnaires used in the general population of children without NDDS cannot be used in the autistic individuals. We explore here the multifactorial pathophysiology of ASD and the role of genetics and the environment in this disease spectrum and focus instead on possible diagnostics that could provide future objective insight into the connection of the gut-brain-microbiome in this disease entity. We provide our own data from both humans and a zebrafish model of ASD called Phelan-McDermid Syndrome. We hope that this review highlights the gaps in our current knowledge on many of these profound NDDs and that it provides a future framework upon which clinicians and researchers can build and network with other interested multidisciplinary specialties.

PMAT variant rs3889348 is associated with metformin-induced gastrointestinal among Chinese Type 2 diabetes patients

Aim: This study examined intronic gene variants for their association with metformin intolerance in a Chinese population, focusing on the plasma monoamine transporter (PMAT) cis-protein expression quantitative trait loci (cis-eQTL) variant rs3889348. Methods: We recruited Type 2 diabetes patients from two hospitals and identified 111 metformin-intolerant patients using a questionnaire, and selected 206 metformin-tolerant patients from 2180 Type 2 diabetes mellitus patients. Genetic testing revealed an association between adverse gastrointestinal (GI) effects and SLC22A1 and PMAT. Results: The single-nucleotide polymorphism rs3889348 is associated with metformin-induced adverse GI effects. Each additional copy of the G allele increases the score by 5.23 (95% CI: 1.82-8.64; p = 0.003). Patients taking more transporter inhibitors were more likely to respond to metformin-induced GI intolerance (p = 0.042). Conclusion: PMAT cis-eQTL rs3889348 was significantly associated with metformin-induced adverse GI effects.

Clinical and biochemical footprints of inherited metabolic disorders. XI. Gastrointestinal symptoms

Inherited metabolic disorders presenting with gastrointestinal (GI) symptoms are characterized by the dysfunction of the esophagus, stomach, small and large intestines, and pancreas. We have summarized associations of signs and symptoms in 339 inherited metabolic diseases presenting with GI symptoms. Feeding difficulties represent the most common abnormality reported for IMDs with GI involvement (37%) followed by intestinal problems (30%), vomiting (22%), stomach and pancreas involvement (8% each), and esophagus involvement (4%). This represents the eleventh of a series of articles attempting to create and maintain a comprehensive list of clinical and metabolic differential diagnoses according to system involvement.

Gastrointestinal Features of 22q11.2 Deletion Syndrome Include Chronic Motility Problems From Childhood to Adulthood

OBJECTIVES

22q11.2 deletion syndrome (22q11.2DS) is the most common chromosomal microdeletion syndrome and has a multisystemic presentation including gastrointestinal features that have not yet been fully described. Our aim was to examine lifetime gastrointestinal problems in a large cohort of patients with 22q11.2DS.

METHODS

All patients followed in the 22q and You Center at the Children's Hospital of Philadelphia (n = 1421) were retrospectively screened for: 1) age ≥ 17 years, 2) documented chromosomal microdeletion within the 22q11.2 LCR22A-LCR22D region, and 3) sufficient clinical data to characterize the adult gastrointestinal phenotype. Gastrointestinal problems in childhood, adolescence, and adulthood were summarized. Statistical association testing of symptoms against other patient characteristics was performed.

RESULTS

Included patients (n = 206; 46% female; mean age, 27 years; median follow-up, 21 years) had similar clinical characteristics to the overall cohort. Genetic distribution was also similar, with 96% having deletions including the critical LCR22A-LCR22B segment (95% in the overall cohort). Most patients experienced chronic gastrointestinal symptoms in their lifetime (91%), but congenital gastrointestinal malformations (3.5%) and gastrointestinal autoimmune diseases (1.5%) were uncommon. Chronic symptoms without anatomic or pathologic abnormalities represented the vast burden of illness. Chronic symptoms in adulthood are associated with other chronic gastrointestinal symptoms and psychiatric comorbidities ( P < 0.01) but not with deletion size or physiologic comorbidities ( P > 0.05). One exception was increased nausea/vomiting in hypothyroidism ( P = 0.002).

CONCLUSIONS

Functional gastrointestinal disorders (FGIDs) are a common cause of ill health in children and adults with 22q11.2DS. Providers should consider screening for the deletion in patients presenting with FGIDs and associated comorbidities such as neuropsychiatric illness, congenital heart disease, and palatal abnormalities.

Role of Intestinal Alkaline Phosphatase in Innate Immunity

Intestinal alkaline phosphatase (IAP) is a multi-functional protein that has been demonstrated to primarily protect the gut. The role of IAP in maintaining intestinal homeostasis is underscored by the observation that IAP expression is defective in many gastrointestinal-related disorders such as inflammatory bowel disease IBD, necrotizing enterocolitis, and metabolic syndrome and that exogenous IAP supplementation improves the outcomes associated with these disorders. Additionally, studies using transgenic IAP-knock out (IAP-KO) mouse models further support the importance of the defensive role of IAP in the intestine. Supplementation of exogenous IAP and cellular overexpression of IAP have also been used in vitro to dissect out the downstream mechanisms of this protein in mammalian cell lines. Some of the innate immune functions of IAP include lipopolysaccharide (LPS) detoxification, protection of gut barrier integrity, regulation of gut microbial communities and its anti-inflammatory roles. A novel function of IAP recently identified is the induction of autophagy. Due to its critical role in the gut physiology and its excellent safety profile, IAP has been used in phase 2a clinical trials for treating conditions such as sepsis-associated acute kidney injury. Many excellent reviews discuss the role of IAP in physiology and pathophysiology and here we extend these to include recent updates on this important host defense protein and discuss its role in innate immunity via its effects on bacteria as well as on host cells. We will also discuss the relationship between IAP and autophagy and how these two pathways may act in concert to protect the gut.

IFN-λ therapy prevents severe gastrointestinal graft-versus-host disease

Immunopathology and intestinal stem cell (ISC) loss in the gastrointestinal (GI) tract is the prima facie manifestation of graft-versus-host disease (GVHD) and is responsible for significant mortality after allogeneic bone marrow transplantation (BMT). Approaches to prevent GVHD to date focus on immune suppression. Here, we identify interferon-λ (IFN-λ; interleukin-28 [IL-28]/IL-29) as a key protector of GI GVHD immunopathology, notably within the ISC compartment. Ifnlr1-/- mice displayed exaggerated GI GVHD and mortality independent of Paneth cells and alterations to the microbiome. Ifnlr1-/- intestinal organoid growth was significantly impaired, and targeted Ifnlr1 deficiency exhibited effects intrinsic to recipient Lgr5+ ISCs and natural killer cells. PEGylated recombinant IL-29 (PEG-rIL-29) treatment of naive mice enhanced Lgr5+ ISC numbers and organoid growth independent of both IL-22 and type I IFN and modulated proliferative and apoptosis gene sets in Lgr5+ ISCs. PEG-rIL-29 treatment improved survival, reduced GVHD severity, and enhanced epithelial proliferation and ISC-derived organoid growth after BMT. The preservation of ISC numbers in response to PEG-rIL-29 after BMT occurred both in the presence and absence of IFN-λ-signaling in recipient natural killer cells. IFN-λ is therefore an attractive and rapidly testable approach to prevent ISC loss and immunopathology during GVHD.

Distinct Small Intestine Mast Cell Histologic Changes in Patients With Hereditary Alpha-tryptasemia and Mast Cell Activation Syndrome

Mast cells (MCs) are important in intestinal homeostasis and pathogen defense but are also implicated in many of the clinical manifestations in disorders such as irritable bowel syndrome. The utility of specific staining for MCs to quantify and phenotype them in intestinal biopsies in patients with gastrointestinal (GI) symptoms is controversial and is not a widely adopted practice. Whether or not intestinal MCs are increased or have a unique phenotype in individuals with hereditary alpha-tryptasemia (HαT), who have extra copies of the MC tryptase gene TPSAB1 and typically elevated baseline serum tryptase levels >8 ng/mL is not known. We examined the duodenal biopsies of 17 patients with HαT and compared them to 15 patients with mast cell activation syndrome who had baseline serum tryptases <8 ng/mL (MCAS-NT) and 12 GI-controls. We determined that the HαT subjects had increased MCs in the duodenum compared with MCAS-NT and GI-controls (median=30.0; interquartile range [IQR]: 20.0 to 40.0 vs. median=15.0; IQR: 5.00 to 20.0; P=0.013 and median=15.0; IQR: 13.8 to 20.0; P=0.004, respectively). These MCs were significantly found in clusters (<15 MCs) and were located throughout the mucosa and submucosa including the superficial villi compared with MCAS-NT and GI-control patients. Spindle-shaped MCs were observed in all groups including controls. These data demonstrate that HαT is associated with increased small intestinal MCs that may contribute to the prevalent GI manifestations observed among individuals with this genetic trait.

Phenome-wide screening of GWAS data reveals the complex causal architecture of obesity

OBJECTIVE

In the present study, we sought to identify causal relationships between obesity and other complex traits and conditions using a data-driven hypothesis-free approach that uses genetic data to infer causal associations.

METHODS

We leveraged available summary-based genetic data from genome-wide association studies on 1498 phenotypes and applied the latent causal variable method (LCV) between obesity and all traits.

RESULTS

We identified 110 traits causally associated with obesity. Of those, 109 were causal outcomes of obesity, while only leg pain in calves was a causal determinant of obesity. Causal outcomes of obesity included 26 phenotypes associated with cardiovascular diseases, 22 anthropometric measurements, nine with the musculoskeletal system, nine with behavioural or lifestyle factors including loneliness or isolation, six with respiratory diseases, five with body bioelectric impedances, four with psychiatric phenotypes, four related to the nervous system, four with disabilities or long-standing illness, three with the gastrointestinal system, three with use of analgesics, two with metabolic diseases, one with inflammatory response and one with the neurodevelopmental disorder ADHD, among others. In particular, some causal outcomes of obesity included hypertension, stroke, ever having a period of extreme irritability, low forced vital capacity and forced expiratory volume, diseases of the musculoskeletal system, diabetes, carpal tunnel syndrome, loneliness or isolation, high leukocyte count, and ADHD.

CONCLUSIONS

Our results indicate that obesity causally affects a wide range of traits and comorbid diseases, thus providing an overview of the metabolic, physiological, and neuropsychiatric impact of obesity on human health.

Clinical characteristics and genetic analysis of A20 haploinsufficiency

PURPOSE

To evaluate the clinical and genetic characteristics of 3 children with Haploinsufficiency of A20 (HA20).

METHODS

The clinical and genetic testing data of 3 children with HA20 treated at Capital Institute of Pediatrics (CIP) between August 2016 and October 2019 were retrospectively analysed.

RESULT

Patient 1 presented with arthritis and inflammatory bowel disease, patient 2 presented with axial spinal arthritis and lupus-like syndrome, and patient 3 presented with recurrent oral ulcers, gastrointestinal ulcers, and perianal abscesses. Regarding laboratory tests, patients were found to have elevated white blood cell (WBC) count, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). The CRP and ESR was reported to be high in all the patients. The WBC was reported to be high in patient 1 and 3. Patient 2 was positive for antinuclear antibodies, anti-Sjögren's syndrome antigen A, dsDNA, rheumatoid factor and Coombs test. Genetic testing showed that all three patients had heterozygous mutation in TNFAIP3 gene. As for the treatment, patient 1 was treated with TNFα antagonist, patient 2 was treated with TNF α antagonist and sulfasalazine, and patient 3 was treated with corticosteroids and thalidomide. Patients 1 and 2 were followed for four and 3 months, respectively. There was an improvement in joint and gastrointestinal symptoms; inflammatory indices and rheumatoid factor (RF) were normal, and dsDNA and Coombs test became negative. Patient 3 was treated at another hospital and showed gradual improvement in oral ulcers and perianal abscesses.

CONCLUSION

HA20 is a single-gene auto-inflammatory disease caused by mutation in tumour necrosis factor (TNF)-α-induced protein 3 (TNFAIP3) gene. It may present as Behçet-like syndrome and resemble various other autoimmune diseases as well. Corticosteroids and immunosuppressive agents are effective treatments, and cytokine antagonists can be used in refractory cases. Whole-exome genetic testing should be proactively performed for children with early-age onset or Behçet-like syndrome to achieve early diagnosis and accurate treatment.

Audit of Gastrointestinal Manifestations in Patients with Loeys-Dietz Syndrome and Vascular Ehlers-Danlos Syndrome

OBJECTIVES

Loeys-Dietz syndrome (LDS) and vascular Ehlers-Danlos Syndrome (vEDS) are genetically heterogeneous heritable disorders of connective tissue. Both are multi-system disorders with dominant vascular pathology and associated gastrointestinal manifestations.

AIM

To summarize the abdominal manifestations found in these two disorders in a cohort of patients seen at Mayo Clinic during a period of 25 years.

METHODS

Data were collected via the advanced cohort explorer (ACE) of Mayo Clinic records from 1994 to 2018 in patients with vEDS or LDS confirmed by genetic testing and/or medical genetics consultation. We extracted information concerning gastrointestinal symptoms, abdominal hernias, and vascular manifestations or complications.

RESULTS

We identified and reviewed records of 68 vEDS and 13 LDS patients. Patients were similar in age at diagnosis and gender distribution. Gastrointestinal symptoms were frequently reported in both disorders and largely similar, although altered bowel function was more prevalent in LDS patients. Hernias were present in similar proportions of patients with vEDS and LDS; however, ventral hernias were more frequent and more likely to be postoperative in vEDS than LDS. LDS patients had more arterial aneurysms overall (76.9% LDS vs. 58% vEDS, p = 0.02) and a higher proportion required arterial repair (69.2% LDS vs. 32.7% vEDS S, p = 0.03). Co-morbidities of autonomic dysfunction, psychopathology (most commonly anxiety, depression, adjustment disorder), and allergy were more prevalent in LDS than vEDS.

CONCLUSION

Patients with vEDS and LDS had a propensity for gastrointestinal symptoms, abdominal hernias, and aneurysm formation, but repair for arterial rupture was more prevalent in LDS than EDS.

Evaluating the role of GSTP1 genetic polymorphism (rs1695, 313A>G) as a predictor in cyclophosphamide-induced toxicities

The association between Glutathione S-transferase Pi 1(GSTP1) genetic polymorphism (rs1695, 313A>G) and cyclophosphamide-induced toxicities has been widely investigated in previous studies, however, the results were inconsistent. This study was performed to further elucidate the association.A comprehensive search was conducted in PubMed, Embase, Web of Science, China National Knowledge Infrastructure, and Wan Fang database up to January 5, 2020. Risk ratios (RRs) and 95% confidence intervals (95% CIs) were used to estimate the association between GSTP1 rs1695 polymorphism and cyclophosphamide-induced hemotoxicity, gastrointestinal toxicity, infection, and neurotoxicity.A total of 13 studies were eventually included. Compared with the GSTP1 rs1695 AA genotype carriers, patients with AG and GG genotypes had an increased risk of cyclophosphamide-induced gastrointestinal toxicity (RR, 1.61; 95% CI, 1.18-2.19; P = .003) and infection (RR, 1.57; 95% CI, 1.00-2.48; P = .05) in the overall population. In the subgroup analyses, there were significant associations between GSTP1 rs1695 polymorphism and the risk of cyclophosphamide-induced myelosuppression (RR, 2.10; 95% CI, 1.60-2.76; P < .00001), gastrointestinal toxicity (RR, 1.77; 95%CI, 1.25-2.53; P = .001), and infection (RR, 2.01; 95% CI, 1.14-3.54; P = .02) in systemic lupus erythematosus (SLE) or lupus nephritis syndrome patients, but not in cancer patients.Our results confirmed an essential role for the GSTP1 rs1695 polymorphism in the prediction of cyclophosphamide-induced myelosuppression, gastrointestinal toxicity, and infection in SLE or lupus nephritis syndrome patients. More studies are necessary to validate our findings in the future.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE): Position paper on diagnosis, prognosis, and treatment by the MNGIE International Network

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive disease caused by TYMP mutations and thymidine phosphorylase (TP) deficiency. Thymidine and deoxyuridine accumulate impairing the mitochondrial DNA maintenance and integrity. Clinically, patients show severe and progressive gastrointestinal and neurological manifestations. The onset typically occurs in the second decade of life and mean age at death is 37 years. Signs and symptoms of MNGIE are heterogeneous and confirmatory diagnostic tests are not routinely performed by most laboratories, accounting for common misdiagnosis. Factors predictive of progression and appropriate tests for monitoring are still undefined. Several treatment options showed promising results in restoring the biochemical imbalance of MNGIE. The lack of controlled studies with appropriate follow-up accounts for the limited evidence informing diagnostic and therapeutic choices. The International Consensus Conference (ICC) on MNGIE, held in Bologna, Italy, on 30 March to 31 March 2019, aimed at an evidence-based consensus on diagnosis, prognosis, and treatment of MNGIE among experts, patients, caregivers and other stakeholders involved in caring the condition. The conference was conducted according to the National Institute of Health Consensus Conference methodology. A consensus development panel formulated a set of statements and proposed a research agenda. Specifically, the ICC produced recommendations on: (a) diagnostic pathway; (b) prognosis and the main predictors of disease progression; (c) efficacy and safety of treatments; and (f) research priorities on diagnosis, prognosis, and treatment. The Bologna ICC on diagnosis, management and treatment of MNGIE provided evidence-based guidance for clinicians incorporating patients' values and preferences.

GWAS of peptic ulcer disease implicates Helicobacter pylori infection, other gastrointestinal disorders and depression

Genetic factors are recognized to contribute to peptic ulcer disease (PUD) and other gastrointestinal diseases, such as gastro-oesophageal reflux disease (GORD), irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Here, genome-wide association study (GWAS) analyses based on 456,327 UK Biobank (UKB) individuals identify 8 independent and significant loci for PUD at, or near, genes MUC1, MUC6, FUT2, PSCA, ABO, CDX2, GAST and CCKBR. There are previously established roles in susceptibility to Helicobacter pylori infection, response to counteract infection-related damage, gastric acid secretion or gastrointestinal motility for these genes. Only two associations have been previously reported for duodenal ulcer, here replicated trans-ancestrally. The results highlight the role of host genetic susceptibility to infection. Post-GWAS analyses for PUD, GORD, IBS and IBD add insights into relationships between these gastrointestinal diseases and their relationships with depression, a commonly comorbid disorder.

Combinatorial Transcriptional Profiling of Mouse and Human Enteric Neurons Identifies Shared and Disparate Subtypes In Situ

BACKGROUND & AIMS

The enteric nervous system (ENS) coordinates essential intestinal functions through the concerted action of diverse enteric neurons (ENs). However, integrated molecular knowledge of EN subtypes is lacking. To compare human and mouse ENs, we transcriptionally profiled healthy ENS from adult humans and mice. We aimed to identify transcripts marking discrete neuron subtypes and visualize conserved EN subtypes for humans and mice in multiple bowel regions.

METHODS

Human myenteric ganglia and adjacent smooth muscle were isolated by laser-capture microdissection for RNA sequencing. Ganglia-specific transcriptional profiles were identified by computationally subtracting muscle gene signatures. Nuclei from mouse myenteric neurons were isolated and subjected to single-nucleus RNA sequencing, totaling more than 4 billion reads and 25,208 neurons. Neuronal subtypes were defined using mouse single-nucleus RNA sequencing data. Comparative informatics between human and mouse data sets identified shared EN subtype markers, which were visualized in situ using hybridization chain reaction.

RESULTS

Several EN subtypes in the duodenum, ileum, and colon are conserved between humans and mice based on orthologous gene expression. However, some EN subtype-specific genes from mice are expressed in completely distinct morphologically defined subtypes in humans. In mice, we identified several neuronal subtypes that stably express gene modules across all intestinal segments, with graded, regional expression of 1 or more marker genes.

CONCLUSIONS

Our combined transcriptional profiling of human myenteric ganglia and mouse EN provides a rich foundation for developing novel intestinal therapeutics. There is congruency among some EN subtypes, but we note multiple species differences that should be carefully considered when relating findings from mouse ENS research to human gastrointestinal studies.

Peryton: a manual collection of experimentally supported microbe-disease associations

We present Peryton (https://dianalab.e-ce.uth.gr/peryton/), a database of experimentally supported microbe-disease associations. Its first version constitutes a novel resource hosting more than 7900 entries linking 43 diseases with 1396 microorganisms. Peryton's content is exclusively sustained by manual curation of biomedical articles. Diseases and microorganisms are provided in a systematic, standardized manner using reference resources to create database dictionaries. Information about the experimental design, study cohorts and the applied high- or low-throughput techniques is meticulously annotated and catered to users. Several functionalities are provided to enhance user experience and enable ingenious use of Peryton. One or more microorganisms and/or diseases can be queried at the same time. Advanced filtering options and direct text-based filtering of results enable refinement of returned information and the conducting of tailored queries suitable to different research questions. Peryton also provides interactive visualizations to effectively capture different aspects of its content and results can be directly downloaded for local storage and downstream analyses. Peryton will serve as a valuable source, enabling scientists of microbe-related disease fields to form novel hypotheses but, equally importantly, to assist in cross-validation of findings.

Relationships among gastrointestinal symptoms, sleep problems, challenging behaviour, comorbid psychopathology and autism spectrum disorder symptoms in children and adolescents with 15q duplication syndrome

BACKGROUND

Comorbidity is the presence of at least two disorders in one person at one time. This study examined the frequency of gastrointestinal (GI) symptoms, sleep problems, comorbid psychopathology, challenging behaviour and autism spectrum disorder (ASD) symptoms in children and adolescents with duplication 15q syndrome (Dup15q), aged 3-17 years. This study also examined whether challenging behaviour in Dup15q is predicted by age, gender, presence of an intellectual disability, sleep problems, GI symptoms and comorbid psychopathology.

METHOD

Parental measures were completed by 101 parents of children and adolescents with Dup15q. Questionnaires were composed of the Children's Sleep Habits Questionnaire, Behavior Problems Inventory - Short Form, GI Symptom Inventory, Social Communication Questionnaire and the Child Behavior Checklist.

RESULTS

Sleep problems (94%), GI symptoms (87%) and challenging behaviour (100%) were common comorbidities represented in the sample in this study. Significant relationships were found between challenging behaviour and the presence of co-occurring sleep problems, GI symptoms, comorbid psychopathology and ASD symptoms. Further analysis revealed that these comorbidities also predicted challenging behaviour.

CONCLUSION

This research demonstrated the importance of studying the relationships between GI symptoms, sleep problems, comorbid psychopathology, ASD symptoms and challenging behaviour in Dup15q and how these conditions can shape the Dup15q phenotype.

Understanding human gut diseases at single-cell resolution

Our understanding of gut functioning and pathophysiology has grown considerably in the past decades, and advancing technologies enable us to deepen this understanding. Single-cell RNA sequencing (scRNA-seq) has opened a new realm of cellular diversity and transcriptional variation in the human gut at a high, single-cell resolution. ScRNA-seq has pushed the science of the digestive system forward by characterizing the function of distinct cell types within complex intestinal cellular environments, by illuminating the heterogeneity within specific cell populations and by identifying novel cell types in the human gut that could contribute to a variety of intestinal diseases. In this review, we highlight recent discoveries made with scRNA-seq that significantly advance our understanding of the human gut both in health and across the spectrum of gut diseases, including inflammatory bowel disease, colorectal carcinoma and celiac disease.

MicroRNAs Regulate Intestinal Immunity and Gut Microbiota for Gastrointestinal Health: A Comprehensive Review

MicroRNAs are small non-coding RNAs regulating gene expression at the post-transcriptional level. The regulation of microRNA expression in the gut intestine is gradually recognized as one of the crucial contributors of intestinal homeostasis and overall health. Recent studies indicated that both the microRNAs endogenous in the gut intestine and exogenous from diets could play influential roles in modulating microbial colonization and intestinal immunity. In this review, we discuss the biological functions of microRNAs in regulating intestinal homeostasis by modulating intestinal immune responses and gut microbiota. We particularly focus on addressing the microRNA-dependent communication and interactions among microRNA, gut microbiota, and intestinal immune system. Besides, we also summarize the roles of diet-derived microRNAs in host-microbiome homeostasis and their benefits on intestinal health. A better understanding of the relationships among intestinal disorders, microRNAs, and other factors influencing intestinal health can facilitate the application of microRNA-based therapeutics for gastrointestinal diseases.

Clinical and molecular characterization of a patient with mitochondrial Neurogastrointestinal Encephalomyopathy

BACKGROUND

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive disorder caused by mutations in TYMP gene, encoding nuclear thymidine phosphorylase (TP). MNGIE mainly presents with gastrointestinal symptoms and is mostly misdiagnosed in many patients as malabsorption syndrome, inflammatory bowel disease, anorexia nervosa, and intestinal pseudo-obstruction. Up to date, more than 80 pathogenic and likely pathogenic mutations associated with the disease have been reported in patients from a wide range of ethnicities. The objective of this study was to investigate the underlying genetic abnormalities in a 25-year-old woman affected with MNGIE.

CASE PRESENTATION

The patient was a 25-year-old female referred to our center with the chief complaint of severe abdominal pain and diarrhea for 2 years that had worsened from 2 months prior to admission. The clinical and para-clinical findings were in favor of mitochondrial neurogastrointestinal encephalomyopathy syndrome. Subsequent genetic studies revealed a novel, private, homozygous nonsense mutation in TYMP gene (c. 1013 C > A, p.S338X). Sanger sequencing confirmed the new mutation in the proband. Multiple sequence alignment showed high conservation of amino acids of this protein across different species.

CONCLUSION

The detected new nonsense mutation in the TYMP gene would be very important for genetic counseling and subsequent early diagnosis and initiation of proper therapy. This novel pathogenic variant would help us establish future genotype-phenotype correlations and identify different pathways related to this disorder.

Mice deficient in GM1 manifest both motor and non-motor symptoms of Parkinson's disease; successful treatment with synthetic GM1 ganglioside

Parkinson's disease (PD) is a major neurodegenerative disorder characterized by a variety of non-motor symptoms in addition to the well-recognized motor dysfunctions that have commanded primary interest. We previously described a new PD mouse model based on heterozygous disruption of the B4galnt1 gene leading to partial deficiency of the GM1 family of gangliosides that manifested several nigrostriatal neuropathological features of PD as well as movement impairment. We now show this mouse also suffers three non-motor symptoms characteristic of PD involving the gastrointestinal, sympathetic cardiac, and cerebral cognitive systems. Treatment of these animals with a synthetic form of GM1 ganglioside, produced by transfected E. coli, proved ameliorative of these symptoms as well as the motor defect. These findings further suggest subnormal GM1 to be a systemic defect constituting a major risk factor in sporadic PD and indicate the B4galnt1(+/-) (HT) mouse to be a true neuropathological model that recapitulates both motor and non-motor lesions of this condition.

Primary hypertrophic osteoarthropathy related gastrointestinal complication has distinctive clinical and pathological characteristics: two cases report and review of the literature

BACKGROUND

Primary hypertrophic osteoarthropathy (PHO) is a rare disease related to HPGD and SLCO2A1 gene mutation. Gastrointestinal involvement of PHO is even rarer with unknown pathogenesis. Clinical features of GI complication in PHO mimics other auto-immune based bowel entities, such as inflammatory bowel diseases and cryptogenic multifocal ulcerous stenosing enteritis (CMUSE). We aimed to analyze the clinical, genetic, radiological and pathological features of Chinese patients with PHO and determine the difference between PHO patients presenting with and without GI involvement.

METHODS

We reported two PHO cases with gastrointestinal involvement and reviewed all the studies of PHO in Chinese population published from January 1, 2000, to April 30, 2018. Clinical and genetic presentations of PHO in Chinese patients were analyzed. We compared the characteristics of those patients with gastrointestinal involvement against those without.

RESULTS

The two patients were both males with complete-form PHO for more than 10 years. GI related symptoms included diarrhea, chronic gastrointestinal hemorrhage, incomplete intestinal obstruction, anemia, and edema, which were unresponsive to etoricoxib treatment. Radiological examinations revealed segmental intestinal stenosis and thickened intestinal wall. Endoscopic findings included multiple ulcers and mucosal inflammation. Both patients had mutations of SLCO2A1 according to sequence analysis. The surgical pathology revealed chronic inflammation involving the intestinal mucosa and submucosa, similar to histological changes in CMUSE. According to the systemic review of 158 Chinese patients with PHO, 17.2% had gastrointestinal involvement, including peptic ulcer, gastric polyps, hypertrophic gastritis, and segmental intestinal stenosis. Patients with gastrointestinal involvement were more likely to have anemia (40.0% vs. 4.5%, P < 0.001), hypoalbuminemia (16.7% vs. 0.9%, P = 0.003), and myelofibrosis (19.0% vs. 0.9%, P = 0.002) than those without. Most patients with gastrointestinal complication had SLCO2A1 mutation (86.7%, 13 /15).

CONCLUSIONS

Digestive tract involvement is uncommon in patients with PHO and often presents with anemia, and hypoalbuminemia resulted from intestinal inflammation. The intestinal pathologic characteristics are distinct from Crohn's disease but similar to CMUSE. Mutations in SLCO2A1 might be the pathogenic cause of GI involvement of PHO. NSAIDs may not be effective for PHO patients with gastrointestinal complications.

Maintenance of Intestinal Epithelial Homeostasis by Zinc Transporters

Zinc is an essential micronutrient for normal organ function, and dysregulation of zinc metabolism has been implicated in a wide range of diseases. Emerging evidence has revealed that zinc transporters play diverse roles in cellular homeostasis and function by regulating zinc trafficking via organelles or the plasma membrane. In the gastrointestinal tract, zinc deficiency leads to diarrhea and dysfunction of intestinal epithelial cells. Studies also showed that zinc transporters are very important in intestinal epithelial homeostasis. In this review, we describe the physiological roles of zinc transporters in intestinal epithelial functions and relevance of zinc transporters in gastrointestinal diseases.

Role of hepatocyte nuclear factor 4-alpha in gastrointestinal and liver diseases

Hepatocyte nuclear factor 4-alpha (HNF4α) is a highly conserved member of nuclear receptor superfamily of ligand-dependent transcription factors that is expressed in liver and gastrointestinal organs (pancreas, stomach, and intestine). In liver, HNF4α is best known for its role as a master regulator of liver-specific gene expression and essential for adult and fetal liver function. Dysregulation of HNF4α expression has been associated with many human diseases such as ulcerative colitis, colon cancer, maturity-onset diabetes of the young, liver cirrhosis, and hepatocellular carcinoma. However, the precise role of HNF4α in the etiology of these human pathogenesis is not well understood. Limited information is known about the role of HNF4α isoforms in liver and gastrointestinal disease progression. There is, therefore, a critical need to know how disruption of the expression of these isoforms may impact on disease progression and phenotypes. In this review, we will update our current understanding on the role of HNF4α in human liver and gastrointestinal diseases. We further provide additional information on possible use of HNF4α as a target for potential therapeutic approaches.

Application of Big Data analysis in gastrointestinal research

Big Data, which are characterized by certain unique traits like volume, velocity and value, have revolutionized the research of multiple fields including medicine. Big Data in health care are defined as large datasets that are collected routinely or automatically, and stored electronically. With the rapidly expanding volume of health data collection, it is envisioned that the Big Data approach can improve not only individual health, but also the performance of health care systems. The application of Big Data analysis in the field of gastroenterology and hepatology research has also opened new research approaches. While it retains most of the advantages and avoids some of the disadvantages of traditional observational studies (case-control and prospective cohort studies), it allows for phenomapping of disease heterogeneity, enhancement of drug safety, as well as development of precision medicine, prediction models and personalized treatment. Unlike randomized controlled trials, it reflects the real-world situation and studies patients who are often under-represented in randomized controlled trials. However, residual and/or unmeasured confounding remains a major concern, which requires meticulous study design and various statistical adjustment methods. Other potential drawbacks include data validity, missing data, incomplete data capture due to the unavailability of diagnosis codes for certain clinical situations, and individual privacy. With continuous technological advances, some of the current limitations with Big Data may be further minimized. This review will illustrate the use of Big Data research on gastrointestinal and liver diseases using recently published examples.

Transcriptome variation in response to gastrointestinal nematode infection in goats

Gastrointestinal nematodes (GIN) are a major constraint for small ruminant production. Due to the rise of anthelmintic resistance throughout the world, alternative control strategies are needed. The development of GIN resistance breeding programs is a promising strategy. However, a better understanding of the mechanisms underlying genetic resistance might lead to more effective breeding programmes. In this study, we compare transcriptome profiling of abomasal mucosa and lymph node tissues from non-infected, resistant and susceptible infected Creole goats using RNA-sequencing. A total of 24 kids, 12 susceptible and 12 GIN resistant based on the estimated breeding value, were infected twice with 10,000 L3 Haemonchus contortus. Physiological and parasitological parameters were monitored during infection. Seven weeks after the second infection, extreme kids (n = 6 resistant and 6 susceptible), chosen on the basis of the fecal egg counts (FEC), and 3 uninfected control animals were slaughtered. Susceptible kids had significantly higher FEC compared with resistant kids during the second infection with no differences in worm burden, male and female worm count or establishment rate. A higher number of differentially expressed genes (DEG) were identified in infected compared with non-infected animals in both abomasal mucosa (792 DEG) and lymph nodes (1726 DEG). There were fewer DEG in resistant versus susceptible groups (342 and 450 DEG, in abomasal mucosa and lymph nodes respectively). ‘Cell cycle’ and ‘cell death and survival’ were the main identified networks in mucosal tissue when comparing infected versus non-infected kids. Antigen processing and presentation of peptide antigen via major histocompatibility complex class I were in the top biological functions for the DEG identified in lymph nodes. The TGFβ1 gene was one of the top 5 upstream DEG in mucosal tissue. Our results are one of the fist investigating differences in the expression profile induced by GIN infection in goats.

Personalized medicine in functional gastrointestinal disorders: Understanding pathogenesis to increase diagnostic and treatment efficacy

There is overwhelming evidence that functional gastrointestinal disorders (FGIDs) are associated with specific mechanisms that constitute important targets for personalized treatment. There are specific mechanisms in patients presenting with functional upper gastrointestinal symptoms (UGI Sx). Among patients with UGI Sx, approximately equal proportions (25%) of patients have delayed gastric emptying (GE), reduced gastric accommodation (GA), both impaired GE and GA, or neither, presumably due to increased gastric or duodenal sensitivity. Treatments targeted to the underlying pathophysiology utilize prokinetics, gastric relaxants, or central neuromodulators. Similarly, specific mechanisms in patients presenting with functional lower gastrointestinal symptoms, especially with diarrhea or constipation, are recognized, including at least 30% of patients with functional constipation pelvic floor dyssynergia and 5% has colonic inertia (with neural or interstitial cells of Cajal loss in myenteric plexus); 25% of patients with diarrhea-predominant irritable bowel syndrome (IBSD) has evidence of bile acid diarrhea; and, depending on ethnicity, a varying proportion of patients has disaccharidase deficiency, and less often sucrose-isomaltase deficiency. Among patients with predominant pain or bloating, the role of fermentable oligosaccharides, disaccharides, monosaccharides and polyols should be considered. Personalization is applied through pharmacogenomics related to drug pharmacokinetics, specifically the role of CYP2D6, 2C19 and 3A4 in the use of drugs for treatment of patients with FGIDs. Single mutations or multiple genetic variants are relatively rare, with limited impact to date on the understanding or treatment of FGIDs. The role of mucosal gene expression in FGIDs, particularly in IBS-D, is the subject of ongoing research. In summary, the time for personalization of FGIDs, based on deep phenotyping, is here; pharmacogenomics is relevant in the use of central neuromodulators. There is still unclear impact of the role of genetics in the management of FGIDs.

Contribution of ghrelin to functional gastrointestinal disorders’ pathogenesis

Functional gastrointestinal disorders (FGID) are heterogeneous disorders with a variety of clinical manifestations, primarily defined by signs and symptoms rather than a definite underlying cause. Their pathophysiology remains obscure and, although it is expected to differ according to the specific FGID, disruptions in the brain-gut axis are now thought to be a common denominator in their pathogenesis. The hormone ghrelin is an important component of this axis, exerting a wide repertoire of physiological actions, including regulation of gastrointestinal motility and protection of mucosal tissue. Ghrelin’s gene shows genetic polymorphism, while its protein product undergoes complex regulation and metabolism in the human body. Numerous studies have studied ghrelin’s relation to the emergence of FGIDs, its potential value as an index of disease severity and as a predictive marker for symptom relief during attempted treatment. Despite the mixed results currently available in scientific literature, the plethora of statistically significant findings shows that disruptions in ghrelin genetics and expression are plausibly related to FGID pathogenesis. The aim of this paper is to review current literature studying these associations, in an effort to uncover certain patterns of alterations in both genetics and expression, which could delineate its true contribution to FGID emergence, either as a causative agent or as a pathogenetic intermediate.

Detection of common diarrhea-causing pathogens in Northern Taiwan by multiplex polymerase chain reaction

Conventional methods for identifying gastroenteritis pathogens are time consuming, more likely to result in a false-negative, rely on personnel with diagnostic expertise, and are dependent on the specimen status. Alternatively, molecular diagnostic methods permit the rapid, simultaneous detection of multiple pathogens with high sensitivity and specificity. The present study compared conventional methods with the Luminex xTAG Gastrointestinal Pathogen Panel (xTAG GPP) for the diagnosis of infectious gastroenteritis in northern Taiwan. From July 2015 to April 2016, 217 clinical fecal samples were collected from patients with suspected infectious gastroenteritis. All specimens were tested using conventional diagnostic techniques following physicians' orders as well as with the xTAG GPP. The multiplex polymerase chain reaction (PCR) approach detected significantly more positive samples with bacterial, viral, and/or parasitic infections as compared to conventional analysis (55.8% vs 40.1%, respectively; P < .001). Moreover, multiplex PCR could detect Escherichia coli O157, enterotoxigenic E coli, Shiga-like toxin-producing E coli, Cryptosporidium, and Giardia, which were undetectable by conventional methods. Furthermore, 48 pathogens in 23 patients (10.6%) with coinfections were identified only using the multiplex PCR approach. Of which, 82.6% were from pediatric patients. Because the detection rates using multiplex PCR are higher than conventional methods, and some pediatric pathogens could only be detected by multiplex PCR, this approach may be useful in rapidly diagnosing diarrheal disease in children and facilitating treatment initiation. Further studies are necessary to determine if multiplex PCR improves patient outcomes and reduces costs.

Matrix metalloproteinase expression is altered in the small and large intestine following fractionated radiation in vivo

PURPOSE

Radiotherapy-induced gut toxicity (RIGT) is associated with significant diarrhoea, pain and rectal bleeding. Matrix metalloproteinases (MMPs) have been reported to be involved in chemotherapy-induced gut toxicity and RIGT following single-dose irradiation in vivo. We therefore proposed MMPs would be involved in the pathobiology of RIGT following fractionated irradiation.

METHODS

Dark Agouti rats were treated with fractionated radiation (3 × 2.5 Gy/week for 6 weeks). Rats were killed at 3, 6 and 15 weeks to represent acute and chronic toxicities. Sections of jejunum and colon were immunostained for MMP-1, MMP-2, MMP-9 and MMP-14. Relative mRNA expression in jejunum and colon was quantified by RT-PCR for MMP-1, MMP-2, MMP-9 and MMP-14. Western blotting was also conducted on jejunum and colon tissue collected at week 6 to determine protein levels of pro- and active MMP-2.

RESULTS

MMP-2 total protein levels, determined by western blotting, significantly increased in both the jejunum (p = 0.0359) and the colon (p = 0.0134) 6 weeks into the fractionated radiation schedule. MMP-1, MMP-2, and MMP-14 mRNA expression significantly increased in the jejunum. MMP-2 mRNA expression was also significantly increased in the colon. Immunostaining of MMP-2 was observed to be increased in both crypt enterocytes and the lamina propria.

CONCLUSIONS

MMP-2 plays a role in the pathobiology of gastrointestinal toxicities following fractionated irradiation. Whilst MMP-1 and MMP-14 mRNA expression was increased, this occurred only in the jejunum, suggesting MMPs are differentially involved in RIGT depending on the intestinal region. Further studies are needed to elucidate the role these mediators play in the development and potentiation of RIGT.

Genetic characterization of indigenous goat breeds in Romania and Hungary with a special focus on genetic resistance to mastitis and gastrointestinal parasitism based on 40 SNPs

Goat breeding has become an important sector in Eastern Europe, with Romania and Hungary being among the major producer countries. Given the limited number of research done up-to-date concerning genetic studies of indigenous goat breeds reared in Romania and Hungary, the current preliminary study aimed to analyze the variability of genes related to mastitis and gastrointestinal parasitism by using Kompetitive Allele Specific PCR (KASP™). We studied 52 single nucleotide polymorphisms (SNPs) belonging to 19 genes in indigenous breeds from both countries, namely Banat's White (n = 36), Carpatina (n = 35) from Romania and Hungarian Milking (n = 79) and identified 16 polymorphic SNPs among 10 genes (PTX3, IL6, CLEC4E, IL8, IL1RN, IL15RA, TNFSF13, SOCS3, TNF and TLR3) in 150 animals. Furthermore, the diversity of the studied breeds was investigated. The PIC values ranged from 0.042 to 0.691. The mean values of observed and expected heterozygosity were 0.235 and 0.246 respectively. The highest observed heterozygosity was obtained for IL15RA g.10343904C>T in Banat's White (0.464), IL15RA g.10354813C>T in Carpatina (0.577) and SOCS3 g.52626440T>G in Hungarian Milking (0.588). Pairwise FST values between the Romanian breeds and Romanian and Hungarian breeds were small (0.009 and 0.015), indicating the close relationship among the studied goat populations. From all the polymorphic SNPs identified, the Hungarian Milking breed showed the highest proportion of polymorphisms (100%), whereas the Carpatina breed had the lowest percentage (87.5%). The highest value of MAF was obtained for SOCS3 g.52626440T>G (0.46), IL15RA g.10343904C>T (0.47), IL15RA g.10344025C>T (0.45), and IL15RA g.10354813C>T (0.42). The 16 polymorphic SNPs identified in a panel of 150 unrelated individuals belonging to three Romanian and Hungarian indigenous goat breeds could be used in future genomic based breeding schemes as markers for genetic resistance to mastitis and gastrointestinal parasitism in goat breeds found in Eastern and Central Europe.

DNA methylation, through DNMT1, has an essential role in the development of gastrointestinal smooth muscle cells and disease

DNA methylation is a key epigenetic modification that can regulate gene expression. Genomic DNA hypomethylation is commonly found in many gastrointestinal (GI) diseases. Dysregulated gene expression in GI smooth muscle cells (GI-SMCs) can lead to motility disorders. However, the consequences of genomic DNA hypomethylation within GI-SMCs are still elusive. Utilizing a Cre-lox murine model, we have generated SMC-restricted DNA methyltransferase 1 (Dnmt1) knockout (KO) mice and analyzed the effects of Dnmt1 deficiency. Dnmt1-KO pups are born smaller than their wild-type littermates, have shortened GI tracts, and lose peristaltic movement due to loss of the tunica muscularis in their intestine, causing massive intestinal dilation, and death around postnatal day 21. Within smooth muscle tissue, significant CpG hypomethylation occurs across the genome at promoters, introns, and exons. Additionally, there is a marked loss of differentiated SMC markers (Srf, Myh11, miR-133, miR-143/145), an increase in pro-apoptotic markers (Nr4a1, Gadd45g), loss of cellular connectivity, and an accumulation of coated vesicles within SMC. Interestingly, we observed consistent abnormal expression patterns of enzymes involved in DNA methylation between both Dnmt1-KO mice and diseased human GI tissue. These data demonstrate that DNA hypomethylation in embryonic SMC, via congenital Dnmt1 deficiency, contributes to massive dysregulation of gene expression and is lethal to GI-SMC. These results suggest that Dnmt1 has a necessary role in the embryonic, primary development process of SMC with consistent patterns being found in human GI diseased tissue.

Loss of CNFY toxin-induced inflammation drives Yersinia pseudotuberculosis into persistency

Gastrointestinal infections caused by enteric yersiniae can become persistent and complicated by relapsing enteritis and severe autoimmune disorders. To establish a persistent infection, the bacteria have to cope with hostile surroundings when they transmigrate through the intestinal epithelium and colonize underlying gut-associated lymphatic tissues. How the bacteria gain a foothold in the face of host immune responses is poorly understood. Here, we show that the CNFY toxin, which enhances translocation of the antiphagocytic Yop effectors, induces inflammatory responses. This results in extensive tissue destruction, alteration of the intestinal microbiota and bacterial clearance. Suppression of CNFY function, however, increases interferon-γ-mediated responses, comprising non-inflammatory antimicrobial activities and tolerogenesis. This process is accompanied by a preterm reprogramming of the pathogen's transcriptional response towards persistence, which gives the bacteria a fitness edge against host responses and facilitates establishment of a commensal-type life style.