Single-nucleus transcriptomic survey of cell diversity and functional maturation in postnatal mammalian hearts.

A fundamental challenge in understanding cardiac biology and disease is that the remarkable heterogeneity in cell type composition and functional states have not been well characterized at single-cell resolution in maturing and diseased mammalian hearts. Massively parallel single-nucleus RNA sequencing (snRNA-seq) has emerged as a powerful tool to address these questions by interrogating the transcriptome of tens of thousands of nuclei isolated from fresh or frozen tissues. snRNA-seq overcomes the technical challenge of isolating intact single cells from complex tissues, including the maturing mammalian hearts; reduces biased recovery of easily dissociated cell types; and minimizes aberrant gene expression during the whole-cell dissociation. Here we applied sNucDrop-seq, a droplet microfluidics-based massively parallel snRNA-seq method, to investigate the transcriptional landscape of postnatal maturing mouse hearts in both healthy and disease states. By profiling the transcriptome of nearly 20,000 nuclei, we identified major and rare cardiac cell types and revealed significant heterogeneity of cardiomyocytes, fibroblasts, and endothelial cells in postnatal developing hearts. When applied to a mouse model of pediatric mitochondrial cardiomyopathy, we uncovered profound cell type-specific modifications of the cardiac transcriptional landscape at single-nucleus resolution, including changes of subtype composition, maturation states, and functional remodeling of each cell type. Furthermore, we employed sNucDrop-seq to decipher the cardiac cell type-specific gene regulatory network (GRN) of GDF15, a heart-derived hormone and clinically important diagnostic biomarker of heart disease. Together, our results present a rich resource for studying cardiac biology and provide new insights into heart disease using an approach broadly applicable to many fields of biomedicine.

Three-Dimensional Imaging of the Enteric Nervous System in Human Pediatric Colon Reveals New Features of Hirschsprung's Disease.

BACKGROUND & AIMS: Hirschsprung's disease is defined by the absence of the enteric nervous system (ENS) from the distal bowel. Primary treatment is "pull-through" surgery to remove bowel that lacks ENS, with reanastomosis of "normal" bowel near the anal verge. Problems after pull-through are common, and some may be due to retained hypoganglionic bowel (ie, low ENS density). Testing this hypothesis has been difficult because counting enteric neurons in tissue sections is unreliable, even for experts. Tissue clearing and 3-dimensional imaging provide better data about ENS structure than sectioning. METHODS: Regions from 11 human colons and 1 ileal specimen resected during Hirschsprung's disease pull-through surgery were cleared, stained with antibodies to visualize the ENS, and imaged by confocal microscopy. Control distal colon from people with no known bowel problems were similarly cleared, stained, and imaged. RESULTS: Quantitative analyses of human colon, ranging from 3 days to 60 years old, suggest age-dependent changes in the myenteric plexus area, ENS ganglion area, percentage of myenteric plexus occupied by ganglia, neurons/mm2, and neuron Feret's diameter. Neuron counting using 3-dimensional images was highly reproducible. High ENS density in neonatal colon allowed reliable neuron counts using 500-µm2 × 500-µm2 regions (36-fold smaller than in adults). Hirschsprung's samples varied 8-fold in proximal margin enteric neuron density and had diverse ENS architecture in resected bowel. CONCLUSIONS: Tissue clearing and 3-dimensional imaging provide more reliable information about ENS structure than tissue sections. ENS structure changes during childhood. Three-dimensional ENS anatomy may provide new insight into human bowel motility disorders, including Hirschsprung's disease.

Geometric engineering of organoid culture for enhanced organogenesis in a dish.

Here, we introduce a facile, scalable engineering approach to enable long-term development and maturation of organoids. We have redesigned the configuration of conventional organoid culture to develop a platform that converts single injections of stem cell suspensions to radial arrays of organoids that can be maintained for extended periods without the need for passaging. Using this system, we demonstrate accelerated production of intestinal organoids with significantly enhanced structural and functional maturity, and their continuous development for over 4 weeks. Furthermore, we present a patient-derived organoid model of inflammatory bowel disease (IBD) and its interrogation using single-cell RNA sequencing to demonstrate its ability to reproduce key pathological features of IBD. Finally, we describe the extension of our approach to engineer vascularized, perfusable human enteroids, which can be used to model innate immune responses in IBD. This work provides an immediately deployable platform technology toward engineering more realistic organ-like structures in a dish.

Rapid Quantification of Ammonium Nitrate and Urea Nitrate Using Liquid Chromatography-High-Resolution Orbitrap Mass Spectrometry.

Resolution and sensitivity improvements in mass spectrometry technology have enabled renewed attempts at solving challenging analytical issues. One such issue involves the analysis of energetic ionic species. Energetic ionic species make up an important class of chemical materials, and a more robust and versatile analytical platform would provide tremendous value to the analytical community. Initial attempts at quantification of energetic ionic species employed high-resolution time-of-flight measurements with crown ether (CE) complexation and flow injection analysis (FIA). In this investigation, ammonium nitrate (AN) and urea nitrate (UN) in the presence of a crown ether complexation agent were explored by using high-resolution orbitrap mass spectrometry. Product ion scans of these signature complexes reveal positive identification of these energetic ionic species. Finally, quantification was demonstrated for both flow injection and liquid chromatography-mass spectrometry (LC-MS) analysis, suggesting the capability for routine and rapid analysis of these energetic ionic materials.

Endoscopic and histologic utility of transnasal endoscopy in pediatric eosinophilic esophagitis.

Unsedated transnasal endoscopy (TNE) is an alternative method of examining the esophageal mucosa in pediatric patients with eosinophilic esophagitis (EoE), reducing cost, time, and risk associated with frequent surveillance esophagogastroduodenoscopies (EGD). Adequacy of transnasal esophageal biopsies for the evaluation of eosinophilic esophagitis histologic scoring system (EoEHSS) has not yet been evaluated. We compared procedure times, endoscopic findings, and EoEHSS scoring for EoE patients undergoing TNE versus standard EGD. Sixty-six TNE patients and 132 EGD controls matched for age (mean age 14.0 years) and disease status (29.3% active) were included. Compared to patients undergoing standard EGD, patients undergoing TNE spent 1.94 h less in the GI suite (p < 0.0001), with comparable occurrence rates of all visual endoscopic findings and most EoEHSS components. TNE serves as a useful tool for long-term disease surveillance, and consideration should be given to its use in clinical trials for EoE.

Gastrointestinal Tract Granular Cell Tumor in the Pediatric Population: A Multicenter Experience.

BACKGROUND: Pediatric granular cell tumors (GCT) involving the gastrointestinal tract (GIT) are rare with limited case report/series reported to date. METHODS: Multicenter retrospective study of pediatric GIT GCT. RESULTS: A total of 10 cases were included in the study with a median age of 13.5 years (range: 7-18 years) and were predominantly female patients (60%). In half of the patients no significant medical history was present with the remaining 5 having Crohn disease (10%), eosinophilic esophagitis (EoE) (10%), Crohn disease and EoE (10%), growth hormone deficiency (10%), and aplasia cutis congenita (10%). The GCT median size was 1.3 cm (range: 1-1.6 cm) and were more commonly located in the esophagus (70%) followed by the stomach (20%) and rectum (10%). Most of the cases showed round/polygonal tumor cells with abundant granular cytoplasm, and none of the cases had nuclear atypia, increased mitotic activity, or tumor cell necrosis. None of our cases received specific therapy for GCT other than clinical follow-up, and none of the patients had evidence of local recurrence or metastatic disease. CONCLUSION: We present our multicenter experience with GIT GCT, all cases had a benign course. Interestingly, 4 of the esophageal GCT cases (including 2 patients with EoE) showed an eosinophil-rich esophagitis in the underlying mucosa.

Esophageal remodeling in eosinophilic esophagitis: Relationships to luminal captured biomarkers of inflammation and periostin.

BACKGROUND: Esophageal remodeling is a factor in disease progression and symptom severity for patients with eosinophilic esophagitis (EoE). Remodeling can begin early in children, resulting in stricture and food impaction. Detection of esophageal remodeling often depends on endoscopy and is appreciated only in its later stages. OBJECTIVE: We sought to determine whether luminal eosinophil-associated and remodeling proteins captured by the esophageal string test (EST) correlate with measures of esophageal remodeling and biomarkers of the epithelial-mesenchymal transition (EMT). METHODS: Patients with EoE (7-18 years old) were enrolled from 2 pediatric hospitals. Participants performed the EST and underwent endoscopy. Histology, distensibility measured by endoluminal functional lumen imaging probe, and symptoms were assessed. Protein quantitation by ELISA was performed on mucosal biopsy and EST samples. Tissue sections were evaluated for EMT. Outcome measures were summarized, and Spearman ρ was used to assess bivariate correlations. RESULTS: Forty patients (68% male) were enrolled (mean age, 12.5 years). Twenty-four (60%) had active disease (≥15 eosinophils per high-power field). EST-captured eotaxin-3, major basic protein 1, EDN, eosinophil peroxidase, and Charcot-Leyden crystal protein/galectin-10 showed significant correlations with peak eosinophils per high-power field (ρ 0.53-0.68, P < .001). Luminal proteins positively correlated with endoscopic features and markers of EMT, and negatively with esophageal distensibility. Periostin was captured by the EST and correlated with eosinophil density, basal zone hyperplasia, endoscopic appearance, and markers of EMT. CONCLUSION: Luminal markers of esophageal remodeling in addition to biomarkers of eosinophilic inflammation correlate with epithelial and functional remodeling in EoE.

Highly Multiplexed Image Analysis of Intestinal Tissue Sections in Patients With Inflammatory Bowel Disease.

BACKGROUND & AIMS: Significant progress has been made since the first report of inflammatory bowel disease (IBD) in 1859, after decades of research that have contributed to the understanding of the genetic and environmental factors involved in IBD pathogenesis. Today, a range of treatments is available for directed therapy, mostly targeting the overactive immune response. However, the mechanisms by which the immune system contributes to disease pathogenesis and progression are not fully understood. One challenge hindering IBD research is the heterogeneous nature of the disease and the lack of understanding of how immune cells interact with one another in the gut mucosa. Introduction of a technology that enables expansive characterization of the inflammatory environment of human IBD tissues may address this gap in knowledge. METHODS: We used the imaging mass cytometry platform to perform highly multiplex image analysis of IBD and healthy deidentified intestine sections (6 Crohn's disease compared to 6 control ileum; 6 ulcerative colitis compared to 6 control colon). The acquired images were graded for inflammation severity by analysis of adjacent H&E tissue sections. We assigned more than 300,000 cells to unique cell types and performed analyses of tissue integrity, epithelial activity, and immune cell composition. RESULTS: The intestinal epithelia of patients with IBD exhibited increased proliferation rates and expression of HLA-DR compared to control tissues, and both features were positively correlated with the severity of inflammation. The neighborhood analysis determined enrichment of regulatory T cell interactions with CD68+ macrophages, CD4+ T cells, and plasma cells in both forms of IBD, whereas activated lysozyme C+ macrophages were preferred regulatory T cell neighbors in Crohn's disease but not ulcerative colitis. CONCLUSIONS: Altogether, our study shows the power of imaging mass cytometry and its ability to both quantify immune cell types and characterize their spatial interactions within the inflammatory environment by a single analysis platform.

A Pattern-based Pathology Approach to Very Early-onset Inflammatory Bowel Disease: Thinking Beyond Crohn Disease and Ulcerative Colitis.

Very early-onset inflammatory bowel disease (VEO-IBD), IBD diagnosed in children younger than 6 years old, is phenotypically and genetically distinct from older onset IBD. Monogenic and digenic causative defects, particularly in primary immunodeficiency and intestinal epithelial barrier genes, have been identified in a subset of patients with VEO-IBD allowing for targeted therapies and improved outcomes. However, these findings are the minority, thus strategies to correctly diagnose patients, including identification of specific histopathologic findings with correlating clinical and laboratory features may provide critical and necessary insight into mechanisms of disease pathogenesis and subsequent therapeutic options. In this article, we review the pathologic findings seen in patients with VEO-IBD and outline a pattern-based approach to diagnosis using examples from primary immunodeficiencies with gastrointestinal manifestations.

Solid-Tubulocystic Variant of Intrahepatic Cholangiocarcinoma: Report of a Pediatric Case With Molecular Characterization.

We present a case of solid-tubulocystic variant of intrahepatic cholangiocarcinoma (also called cholangioblastic variant of intrahepatic cholangiocarcinoma) in a 15-year-old girl, the youngest patient reported to date. The tumor was located in the left lobe of the liver, predominantly solid with cystic areas, and measured 16 cm in greatest dimension. Microscopic examination showed 2 major histologic patterns: a mixed pattern with solid, tubulocystic, macrocystic, trabecular, and nested growth, diffuse cytokeratin 7/19 and weak neuroendocrine immunoreactivity, and low Ki-67 index; and a more compact, macrotrabecular/gyriform pattern with focal CK7/19, stronger neuroendocrine reactivity, and higher Ki-67 index. Inhibin immunoreactivity was diffuse throughout both patterns. Treatment included tumor resection with negative margins and 8 cycles of capecitabine chemotherapy; the patient is alive with no evidence of tumor 2.5 years after resection. Although molecular characterization of the tumor at the time of resection was unrevealing, a recent study has identified a novel NIPBL-NACC1 fusion transcript in this tumor type, which we have confirmed in this case. This case expands the reported age range of this rare tumor type and confirms a recently-reported diagnostic genomic alteration. Awareness of this rare entity affecting pediatric patients is crucial to avoid confusion with similar-appearing neoplasms.

Robust, 3-Dimensional Visualization of Human Colon Enteric Nervous System Without Tissue Sectioning.

BACKGROUND & AIMS: Small, 2-dimensional sections routinely used for human pathology analysis provide limited information about bowel innervation. We developed a technique to image human enteric nervous system (ENS) and other intramural cells in 3 dimensions. METHODS: Using mouse and human colon tissues, we developed a method that combines tissue clearing, immunohistochemistry, confocal microscopy, and quantitative analysis of full-thickness bowel without sectioning to quantify ENS and other intramural cells in 3 dimensions. RESULTS: We provided 280 adult human colon confocal Z-stacks from persons without known bowel motility disorders. Most of our images were of myenteric ganglia, captured using a 20× objective lens. Full-thickness colon images, viewed with a 10× objective lens, were as large as 4 × 5 mm2. Colon from 2 pediatric patients with Hirschsprung disease was used to show distal colon without enteric ganglia, as well as a transition zone and proximal pull-through resection margin where ENS was present. After testing a panel of antibodies with our method, we identified 16 antibodies that bind to molecules in neurons, glia, interstitial cells of Cajal, and muscularis macrophages. Quantitative analyses demonstrated myenteric plexus in 24.5% ± 2.4% of flattened colon Z-stack area. Myenteric ganglia occupied 34% ± 4% of myenteric plexus. Single myenteric ganglion volume averaged 3,527,678 ± 573,832 mm3 with 38,706 ± 5763 neuron/mm3 and 129,321 ± 25,356 glia/mm3. Images of large areas provided insight into why published values of ENS density vary up to 150-fold-ENS density varies greatly, across millimeters, so analyses of small numbers of thin sections from the same bowel region can produce varying results. Neuron subtype analysis revealed that approximately 56% of myenteric neurons stained with neuronal nitric oxide synthase antibody and approximately 33% of neurons produce and store acetylcholine. Transition zone regions from colon tissues of patients with Hirschsprung disease had ganglia in multiple layers and thick nerve fiber bundles without neurons. Submucosal neuron distribution varied among imaged colon regions. CONCLUSIONS: We developed a 3-dimensional imaging method for colon that provides more information about ENS structure than tissue sectioning. This approach could improve diagnosis for human bowel motility disorders and may be useful for other bowel diseases as well.

Posttranscriptional regulation of colonic epithelial repair by RNA binding protein IMP1/IGF2BP1.

RNA binding proteins, including IMP1/IGF2BP1, are essential regulators of intestinal development and cancer. Imp1 hypomorphic mice exhibit gastrointestinal growth defects, yet the specific role for IMP1 in colon epithelial repair is unclear. Our prior work revealed that intestinal epithelial cell-specific Imp1 deletion (Imp1ΔIEC ) was associated with better regeneration in mice after irradiation. Here, we report increased IMP1 expression in patients with Crohn's disease and ulcerative colitis. We demonstrate that Imp1ΔIEC mice exhibit enhanced recovery following dextran sodium sulfate (DSS)-mediated colonic injury. Imp1ΔIEC mice exhibit Paneth cell granule changes, increased autophagy flux, and upregulation of Atg5. In silico and biochemical analyses revealed direct binding of IMP1 to MAP1LC3B, ATG3, and ATG5 transcripts. Genetic deletion of essential autophagy gene Atg7 in Imp1ΔIEC mice revealed increased sensitivity of double-mutant mice to colonic injury compared to control or Atg7 single mutant mice, suggesting a compensatory relationship between Imp1 and the autophagy pathway. The present study defines a novel interplay between IMP1 and autophagy, where IMP1 may be transiently induced during damage to modulate colonic epithelial cell responses to damage.

Genomic integration of ERRγ-HNF1ß regulates renal bioenergetics and prevents chronic kidney disease.

Mitochondrial dysfunction is increasingly recognized as a critical determinant of both hereditary and acquired kidney diseases. However, it remains poorly understood how mitochondrial metabolism is regulated to support normal kidney function and how its dysregulation contributes to kidney disease. Here, we show that the nuclear receptor estrogen-related receptor gamma (ERRγ) and hepatocyte nuclear factor 1 beta (HNF1ß) link renal mitochondrial and reabsorptive functions through coordinated epigenomic programs. ERRγ directly regulates mitochondrial metabolism but cooperatively controls renal reabsorption via convergent binding with HNF1ß. Deletion of ERRγ in renal epithelial cells (RECs), in which it is highly and specifically expressed, results in severe renal energetic and reabsorptive dysfunction and progressive renal failure that recapitulates phenotypes of animals and patients with HNF1ß loss-of-function gene mutations. Moreover, ERRγ expression positively correlates with renal function and is decreased in patients with chronic kidney disease (CKD). REC-ERRγ KO mice share highly overlapping renal transcriptional signatures with human patients with CKD. Together these findings reveal a role for ERRγ in directing independent and HNF1ß-integrated programs for energy production and use essential for normal renal function and the prevention of kidney disease.

Protein-elongating mutations in MYH11 are implicated in a dominantly inherited smooth muscle dysmotility syndrome with severe esophageal, gastric, and intestinal disease.

Gastrointestinal motility disorders include a spectrum of mild to severe clinical phenotypes that are caused by smooth muscle dysfunction. We investigated the genetic etiology of severe esophageal, gastric, and colonic dysmotility in two unrelated families with autosomal dominant disease presentation. Using exome sequencing, we identified a 2 base pair insertion at the end of the myosin heavy chain 11 (MYH11) gene in all affected members of Family 1 [NM_001040113:c.5819_5820insCA(p.Gln1941Asnfs*91)] and a 1 base pair deletion at the same genetic locus in Proband 2 [NM_001040113:c.5819del(p.Pro1940Hisfs*91)]. Both variants are predicted to result in a similarly elongated protein product. Heterozygous dominant negative MYH11 pathogenic variants have been associated with thoracic aortic aneurysm and dissection while biallelic null alleles have been associated with megacystis microcolon intestinal hypoperistalsis syndrome. This report highlights heterozygous protein-elongating MYH11 variants affecting the SM2 isoforms of MYH11 as a cause for severe gastrointestinal dysmotility, and we hypothesize that the mechanistic pathogenesis of this disease, dominant hypercontractile loss-of-function, is distinct from those implicated in other diseases involving MYH11 dysfunction.

Efficacy of Epicutaneous Immunotherapy in Children With Milk-Induced Eosinophilic Esophagitis.

BACKGROUND & AIMS: Eosinophilic esophagitis (EoE) is caused by an immune response to specific food allergens. There are no approved therapies beyond avoidance of the allergen(s) or treatment of inflammation. Epicutaneous immunotherapy (EPIT) reduces features of eosinophilic gastrointestinal disease in mice and pigs. We performed randomized, placebo-controlled study to determine the safety and efficacy of EPIT with Viaskin milk in children with milk-induced EoE. METHODS: In a double-blind study, 20 children (4-17 years old) with milk-induced EoE were randomly assigned to groups given EPIT with Viaskin milk (n = 15) or placebo (n = 5) for 9 months during a milk-free period, followed by milk-containing diet for 2 months with EPIT. Then, subjects underwent upper endoscopy analysis, biopsies were collected, and maximum esophageal eosinophil counts were determined and was the primary endpoint. After upper endoscopy, patients were given open-label EPIT for 11 months (open-label phase). The subjects were allowed to consume milk if they had maximum values of fewer than 10 eosinophils/high-power field (eos/hpf); otherwise, they remained on a milk-free diet until the last 2 months of the open-label phase. RESULTS: In the intent to treat population, there was no significant difference between the Viaskin milk group in mean eos/hpf (50.1 ± 43.97 eos/hpf) vs the placebo group (48.20 ± 56.98 eos/hpf). However, in the per-protocol population (7 patients given Viaskin milk and 2 patients given placebo), patients given Viaskin milk patients had a significantly lower mean eos/hpf count (25.57 ± 31.19) than patients given placebo (95.00 ± 63.64) (p = .038). At the end of the open-label phase, 9 of 19 evaluable subjects had mean values of fewer than 15 eos/hpf (47% response). The number of adverse events did not differ significantly between the Viaskin milk and placebo groups; there was 1 serious adverse event in the placebo group. CONCLUSIONS: In a pilot study of pediatric patients with EoE given EPIT with Viaskin milk or placebo for 11 months, we found no significant difference between groups for the maximum eosinophil count at the end of the study. However, findings from a per-protocol analysis indicate that Viaskin milk can reduce eos/hpf. At study completion, 47% of patients who continued open-label Viaskin milk for an additional 11 months had mean values of fewer than 15 eos/hpf. ClinicalTrials.gov no: NCT02579876.

Persistent Basal Cell Hyperplasia Is Associated With Clinical and Endoscopic Findings in Patients With Histologically Inactive Eosinophilic Esophagitis.

BACKGROUND & AIMS: Although eosinophil count is the standard used to monitor disease activity in patients with eosinophilic esophagitis (EoE), there are often disparities between patient-reported symptoms and eosinophil counts. We examined the prevalence of epithelial alterations, namely basal cell hyperplasia (BCH) and spongiosis, among patients with inactive EoE (eosinophil counts below 15 following therapy) and aimed to determine whether maintenance of these changes in epithelial morphology are associated with persistent clinical findings. METHODS: Esophageal biopsies of 243 patients (mean age, 16.9 years) undergoing routine endoscopy at the University of Pennsylvania were evaluated for epithelial BCH and spongiosis. Univariable analysis was used to calculate the association between epithelial changes and symptoms as well as endoscopic findings and peak eosinophil count. We validated our findings using data from a cohort of patients at the University of North Carolina. RESULTS: The discovery and validation cohorts each included patients with inactive EoE, based on histologic factors, but ongoing BCH and spongiosis. Ongoing BCH, but not spongiosis, in patients with inactive EoE was associated with symptoms (odds ratio, 2.14; 95% CI, 1.03-4.42; P = .041) and endoscopic findings (odds ratio, 7.10; 95% CI, 3.12-16.18; P < .001). CONCLUSIONS: In patients with EoE, the presence of BCH might indicate ongoing disease activity, independent of eosinophil count. This might account for the persistent symptoms in patients who are considered to be in remission based on histologic factors.

Loss of HDAC6 alters gut microbiota and worsens obesity.

Alterations in gut microbiota are known to affect intestinal inflammation and obesity. Antibiotic treatment can affect weight gain by elimination of histone deacetylase (HDAC) inhibitor-producing microbes, which are anti-inflammatory by augmenting regulatory T (Treg) cells. We asked whether mice that lack HDAC6 and have potent suppressive Treg cells are protected from microbiota-induced accelerated weight gain. We crossed wild-type and HDAC6-deficient mice and subjected the offspring to perinatal penicillin, inducing weight gain via microbiota disturbance. We observed that male HDAC6-deficient mice were not protected and developed profoundly accelerated weight gain. The antibiotic-exposed HDAC6-deficient mice showed a mixed immune phenotype with increased CD4+ and CD8+ T-cell activation yet maintained the enhanced Treg cell-suppressive function phenotype characteristic of HDAC6-deficient mice. 16S rRNA sequencing of mouse fecal samples reveals that their microbiota diverged with time, with HDAC6 deletion altering microbiome composition. On a high-fat diet, HDAC6-deficient mice were depleted in representatives of the S24-7 family and Lactobacillus but enriched with Bacteroides and Parabacteroides; these changes are associated with obesity. Our findings further our understanding of the influence of HDACs on microbiome composition and are important for the development of HDAC6 inhibitors in the treatment of human diseases.-Lieber, A. D., Beier, U. H., Xiao, H., Wilkins, B. J., Jiao, J., Li, X. S., Schugar, R. C., Strauch, C. M., Wang, Z., Brown, J. M., Hazen, S. L., Bokulich, N. A., Ruggles, K. V., Akimova, T., Hancock, W. W., Blaser, M. J. Loss of HDAC6 alters gut microbiota and worsens obesity.

EoE disease monitoring: Where we are and where we are going.

OBJECTIVE: To review literature on various methods of monitoring and characterizing eosinophilic esophagitis (EoE) with respect to their validity as well as risk to the patient. DATA SOURCES: A literature search was performed using PubMed with keyword combinations of EoE and monitoring as well as various techniques used for monitoring, including but not limited to, symptoms, endoscopy, histology, fluoroscopy, FLIP, noninvasive monitoring, and biomarkers. STUDY SELECTIONS: Case-control studies, observational studies, peer-reviewed reviews and guidelines, and systematic reviews were selected, reviewed, and summarized here. RESULTS: A wealth of research regarding monitoring of EoE is currently being undertaken and published. Our review highlights those that have been validated and are currently being used, as well as some that show promise for future monitoring and disease characterization. CONCLUSION: Eosinophilic esophagitis is a chronic condition that at this time requires upper endoscopy as the gold standard of diagnosis and monitoring. There is a great need in the field for less invasive monitoring tools and better ways to characterize disease to allow for personalization of therapies.

Gastrointestinal Polyposis in Pediatric Patients.

Gastrointestinal polyps are mucosal overgrowths that, if unchecked, can undergo malignant transformation. Although relatively uncommon in the pediatric age group, they can be the harbingers of multiorgan cancer risk and require close management and follow-up. Additionally, as many polyposis syndromes are inherited, appropriate genetic testing and management of relatives is vital for the health of the entire family. In this review, we discuss both common and uncommon childhood gastrointestinal polyposis syndromes in terms of clinical presentation, management, and surveillance. We also detail any additional malignancy risk and surveillance required in the pediatric age group (<21 years old). Through this review, we provide a framework for gastroenterologists to manage the multifaceted nature of pediatric polyposis syndromes.

Lipid malabsorption from altered hormonal signaling changes early gut microbial responses.

Infants with congenital diarrheal disorders caused by enteroendocrine cell dysgenesis, or the loss of intestinal endocrine cells, causes severe malabsorptive diarrhea, though the mechanism is not fully understood. The transcription factor "aristaless-related homeobox" (Arx) is specifically expressed in intestinal endocrine cells. This study seeks to characterize the early malabsorptive phenotype of mice deficient for Arx using cell-type specific gene ablation in Villin-Cre; ArxloxP/Y ( Arxint) mice. In neonatal mice, the loss of intestinal Arx caused the loss of intestinal hormones, such as cholecystokinin, secretin, neurotensin, glucose-dependent insulinotropic peptide, glucagon-like peptide (GLP)-1 and GLP-2 but also upregulation of somatostatin. Arxint mice exhibited steatorrhea with the loss of lipid transport in duodenal enterocytes, upregulation of lysozyme-positive Paneth cells, and a secondary increase in antimicrobial peptides, specifically Reg3ß. When the epithelium from Arxint mice was cultured ex vivo into enteroids, however, the Reg3ß upregulation was lost under the sterile conditions. Thus, Arx is required for the appropriate lineage allocation of multiple enteroendocrine subtypes. We concluded that altered hormonal signaling caused by Arx deficiency results in lipid malabsorption, premature Paneth cell differentiation, and an inflammatory response, including neutrophilic infiltrates and a microbiota-triggered upregulation of Reg3ß. NEW & NOTEWORTHY The enteroendocrine transcription factor aristaless-related homeobox (Arx) plays a key role in lineage specification. Changes in hormonal expression mediated by Arx lead to lipid malabsorption and premature Paneth cell development. Furthermore, global profiling of whole intestine from Arx-deficient mice revealed significant upregulation of antimicrobial peptides. This antimicrobial response in Arx-deficient animals is lost under sterile culture conditions of enteroids.