Chronic Use of Proton Pump Inhibitors Is Associated With an Increased Risk of Immune Checkpoint Inhibitor Colitis in Renal Cell Carcinoma.

INTRODUCTION: Immune checkpoint inhibitors (ICIs) have become a standard of care in metastatic renal cell carcinoma (mRCC) but are associated with immune-related adverse events (irAEs) including colitis. Growing evidence suggests proton pump inhibitors (PPIs) increase the risk of inflammatory bowel disease (IBD). Given the pathophysiological overlap between IBD and ICI colitis, we sought to evaluate the relationship between PPI use and ICI colitis in mRCC patients. PATIENTS AND METHODS: We performed a retrospective study of adult patients who received ICI therapy for mRCC between 2015 and 2018 at University of Texas Southwestern Medical Center affiliated hospitals. Clinical characteristics, oncological outcomes, ICI colitis details, and PPI use details were collected by manual chart review. The diagnosis of ICI colitis was made via biopsy when available, or by clinical criteria (symptoms and response to immunosuppressive therapy) when biopsy specimens were unavailable or inconclusive. Univariable and multivariable logistic regression analyses were conducted to assess the potential contribution of PPIs to ICI colitis. RESULTS: A total of 176 patients received ICI therapy for mRCC, of which 16 (9.1%) were diagnosed with ICI colitis. Patients with ICI colitis presented with elevated stool lactoferritin and calprotectin and a wide range of endoscopic and histologic findings. There were no significant differences between patients with and without ICI colitis in age, gender, medical comorbidities, RCC history, and overall survival. However, exposure to ipilimumab and PPI use were more frequently observed in patients with ICI colitis than those without. In univariable and multivariable logistic regression analyses, exposure to ipilimumab and chronic use of PPIs > 8 weeks were significantly associated with ICI colitis. CONCLUSION: In addition to ipilimumab use, chronic use of PPIs may be associated with ICI colitis in patients with mRCC.

Chronic Inflammation in Ulcerative Colitis Causes Long-Term Changes in Goblet Cell Function.

BACKGROUND & AIMS: One of the features of ulcerative colitis (UC) is a defect in the protective mucus layer. This has been attributed to a reduced number of goblet cells (GCs). However, it is not known whether abnormal GC mucus secretion also contributes to the reduced mucus layer. Our aims were to investigate whether GC secretion was abnormal in UC and exists as a long-term effect of chronic inflammation. METHODS: Colonoids were established from intestinal stem cells of healthy subjects (HS) and patients with UC. Colonoids were maintained as undifferentiated (UD) or induced to differentiate (DF) and studied as three-dimensional or monolayers on Transwell filters. Total RNA was extracted for quantitative real-time polymerase chain reaction analysis. Carbachol and prostaglandin E2 mediated mucin stimulation was examined by MUC2 IF/confocal microscopy and transmission electron microscopy. RESULTS: Colonoids from UC patients can be propagated over many passages; however, they exhibit a reduced rate of growth and transepithelial electrical resistance compared with HS. Differentiated UC colonoid monolayers form a thin and non-continuous mucus layer. UC colonoids have increased expression of secretory lineage markers ATOH1 and SPDEF, along with MUC2 positive GCs, but failed to secrete mucin in response to the cholinergic agonist carbachol and prostaglandin E2, which caused increased secretion in HS. Exposure to tumor necrosis factor α (5 days) reduced the number of GCs, with a greater percentage decrease in UC colonoids compared with HS. CONCLUSIONS: Chronic inflammation in UC causes long-term changes in GCs, leading to abnormal mucus secretion. This continued defect in GC mucus secretion may contribute to the recurrence in UC.

Fluid shear stress enhances differentiation of jejunal human enteroids in Intestine-Chip.

There is increasing evidence that the study of normal human enteroids duplicates many known aspects of human intestinal physiology. However, this epithelial cell-only model lacks the many nonepithelial intestinal cells present in the gastrointestinal tract and exposure to the mechanical forces to which the intestine is exposed. We tested the hypothesis that physical shear forces produced by luminal and blood flow would provide an intestinal model more closely resembling normal human jejunum. Jejunal enteroid monolayers were studied in the Emulate, Inc. Intestine-Chip under conditions of constant luminal and basolateral flow that was designed to mimic normal intestinal fluid flow, with human umbilical vein endothelial cells (HUVECs) on the basolateral surface and with Wnt3A, R-spondin, and Noggin only on the luminal surface. The jejunal enteroids formed monolayers that remained confluent for 6-8 days, began differentiating at least as early as day 2 post plating, and demonstrated continuing differentiation over the entire time of the study, as shown by quantitative real-time polymerase chain reaction and Western blot analysis. Differentiation impacted villus genes and proteins differently with early expression of regenerating family member 1α (REG1A), early reduction to a low but constant level of expression of Na+-K+-2Cl- cotransporter 1 (NKCC1), and increasing expression of sucrase-isomaltase (SI) and downregulated in adenoma (DRA). These results were consistent with continual differentiation, as was shown to occur in mouse villus enterocytes. Compared with differentiated enteroid monolayers grown on Transwell inserts, enteroids exposed to flow were more differentiated but exhibited increased apoptosis and reduced carbohydrate metabolism, as shown by proteomic analysis. This study of human jejunal enteroids-on-chip suggests that luminal and basolateral flow produce a model of continual differentiation over time and NaCl absorption that mimics normal intestine and should provide new insights in intestinal physiology.NEW & NOTEWORTHY This study showed that polarized enteroid models in which there is no basolateral Wnt3a, are differentiated, regardless of the Wnt3a status of the apical media. The study supports the concept that in the human intestine villus differentiation is not an all or none phenomenon, demonstrating that at different days after lack of basolateral Wnt exposure, clusters of genes and proteins exist geographically along the villus with different domains having different functions.

Intestinal stem cell-derived enteroids from morbidly obese patients preserve obesity-related phenotypes: Elevated glucose absorption and gluconeogenesis.

OBJECTIVE: The mechanisms behind the efficacy of bariatric surgery (BS) for treating obesity and type 2 diabetes, particularly with respect to the influence of the small bowel, remain poorly understood. In vitro and animal models are suboptimal with respect to their ability to replicate the human intestinal epithelium under conditions induced by obesity. Human enteroids have the potential to accelerate the development of less invasive anti-obesity therapeutics if they can recapitulate the pathophysiology of obesity. Our aim was to determine whether adult stem cell-derived enteroids preserve obesity-characteristic patient-specific abnormalities in carbohydrate absorption and metabolism. METHODS: We established 24 enteroid lines representing 19 lean, overweight, or morbidly obese patients, including post-BS cases. Dietary glucose absorption and gluconeogenesis in enteroids were measured. The expression of carbohydrate transporters and gluconeogenic enzymes was assessed and a pharmacological approach was used to dissect the specific contribution of each transporter or enzyme to carbohydrate absorption and metabolism, respectively. RESULTS: Four phenotypes representing the relationship between patients' BMI and intestinal dietary sugar absorption were found, suggesting that human enteroids retain obese patient phenotype heterogeneity. Intestinal glucose absorption and gluconeogenesis were significantly elevated in enteroids from a cohort of obese patients. Elevated glucose absorption was associated with increased expression of SGLT1 and GLUT2, whereas elevated gluconeogenesis was related to increased expression of GLUT5, PEPCK1, and G6Pase. CONCLUSIONS: Obesity phenotypes preserved in human enteroids provide a mechanistic link to aberrant dietary carbohydrate absorption and metabolism. Enteroids can be used as a preclinical platform to understand the pathophysiology of obesity, study the heterogeneity of obesity mechanisms, and identify novel therapeutics.

Mechanical Stimuli Affect Escherichia coli Heat-Stable Enterotoxin-Cyclic GMP Signaling in a Human Enteroid Intestine-Chip Model.

Modeling host-pathogen interactions with human intestinal epithelia using enteroid monolayers on permeable supports (such as Transwells) represents an alternative to animal studies or use of colon cancer-derived cell lines. However, the static monolayer model does not expose epithelial cells to mechanical forces normally present in the intestine, including luminal flow and serosal blood flow (shear force) or peristaltic forces. To determine the contribution of mechanical forces in the functional response of human small intestine to a virulence factor of a pathogenic intestinal bacterium, human jejunal enteroids were cultured as monolayers in microengineered fluidic-based Organ-Chips (Intestine-Chips) exposed to enterotoxigenic Escherichia coli heat-stable enterotoxin A (ST) and evaluated under conditions of static fluid, apical and basolateral flow, and flow plus repetitive stretch. Application of flow increased epithelial cell height and apical and basolateral secretion of cyclic GMP (cGMP) under baseline, unstimulated conditions. Addition of ST under flow conditions increased apical and basolateral secretion of cGMP relative to the level under static conditions but did not enhance intracellular cGMP accumulation. Cyclic stretch did not have any significant effect beyond that contributed by flow. This study demonstrates that fluid flow application initiates changes in intestinal epithelial cell characteristics relative to those of static culture conditions under both baseline conditions and with exposure to ST enterotoxin and suggests that further investigations of the application of these mechanical forces will provide insights into physiology and pathophysiology that more closely resemble intact intestine than study under static conditions.

cAMP Stimulates SLC26A3 Activity in Human Colon by a CFTR-Dependent Mechanism That Does Not Require CFTR Activity.

BACKGROUND & AIMS: SLC26A3 (DRA) is an electroneutral Cl-/HCO3- exchanger that is present in the apical domain of multiple intestinal segments. An area that has continued to be poorly understood is related to DRA regulation in acute adenosine 3',5'-cyclic monophosphate (cAMP)-related diarrheas, in which DRA appears to be both inhibited as part of NaCl absorption and stimulated to contribute to increased HCO3- secretion. Different cell models expressing DRA have shown that cAMP inhibits, stimulates, or does not affect its activity. METHODS: This study re-evaluated cAMP regulation of DRA using new tools, including a successful knockout cell model, a specific DRA inhibitor (DRAinh-A250), specific antibodies, and a transport assay that did not rely on nonspecific inhibitors. The studies compared DRA regulation in colonoids made from normal human colon with regulation in the colon cancer cell line, Caco-2. RESULTS: DRA is an apical protein in human proximal colon, differentiated colonoid monolayers, and Caco-2 cells. It is glycosylated and appears as 2 bands. cAMP (forskolin) acutely stimulated DRA activity in human colonoids and Caco-2 cells. In these cells, DRA is the predominant apical Cl-/HCO3- exchanger and is inhibited by DRAinh-A250 with a median inhibitory concentration of 0.5 and 0.2 µmol/L, respectively. However, there was no effect of cAMP in HEK293/DRA cells that lacked a cystic fibrosis transmembrane conductance regulator (CFTR). When CFTR was expressed in HEK293/DRA cells, cAMP also stimulated DRA activity. In all cases, cAMP stimulation of DRA was not inhibited by CFTRinh-172. CONCLUSIONS: DRA is acutely stimulated by cAMP by a process that is CFTR-dependent, but appears to be one of multiple regulatory effects of CFTR that does not require CFTR activity.

[Establishment and application of gastric and gastric cancer organoids].

Gastric organoid is the organotypic cultures of gastric stem cells or pluripotent stem cells. Gastric organoid is comprised of all major types of gastric epithelial cells and represent the architecture and function remarkably similar to those of the gastric epithelium, faithfully recapitulating the functional gastric epithelium ex vivo. As ideal basic experimental model, gastric organoid has advantages over animal models and conventional cell model in many aspects. Gastric organoid derived from human gastric tissue, in particular, allows the investigation of the function of human stomach in the ex vivo setting. It has now been applied in the field of formation and physiology of the stomach, Helicobacter pylori infection-associated diseases, research of the pathogenic gene, screening and development of drugs, and regenerative medicine. What is more, as an innovative pre-clinical cancer model, gastric cancer organoid has provided important insights in the development of gastric cancer and screening of antitumor drugs, such as simulating the occurrence and development of gastric cancer, screening and development of antitumor drugs, personalized medication and targeted therapy for gastric cancer, and combined application with patient-derived xenograft. In this review, we summarize the establishment and application of gastric and gastric cancer organoids, especially in modeling gastric cancer, basic research and drug development.

Enterohemorrhagic E. coli (EHEC)-Secreted Serine Protease EspP Stimulates Electrogenic Ion Transport in Human Colonoid Monolayers.

One of the characteristic manifestations of Shiga-toxin-producing Escherichia coli (E. coli) infection in humans, including EHEC and Enteroaggregative E. coli O104:H4, is watery diarrhea. However, neither Shiga toxin nor numerous components of the type-3 secretion system have been found to independently elicit fluid secretion. We used the adult stem-cell-derived human colonoid monolayers (HCM) to test whether EHEC-secreted extracellular serine protease P (EspP), a member of the serine protease family broadly expressed by diarrheagenic E. coli can act as an enterotoxin. We applied the Ussing chamber/voltage clamp technique to determine whether EspP stimulates electrogenic ion transport indicated by a change in short-circuit current (Isc). EspP stimulates Isc in HCM. The EspP-stimulated Isc does not require protease activity, is not cystic fibrosis transmembrane conductance regulator (CFTR)-mediated, but is partially Ca2+-dependent. EspP neutralization with a specific antibody reduces its potency in stimulating Isc. Serine Protease A, secreted by Enteroaggregative E. coli, also stimulates Isc in HCM, but this current is CFTR-dependent. In conclusion, EspP stimulates colonic CFTR-independent active ion transport and may be involved in the pathophysiology of EHEC diarrhea. Serine protease toxins from E. coli pathogens appear to serve as enterotoxins, potentially significantly contributing to watery diarrhea.

Molecular Basis and Differentiation-Associated Alterations of Anion Secretion in Human Duodenal Enteroid Monolayers.

BACKGROUND & AIMS: Human enteroids present a novel tool to study human intestinal ion transport physiology and pathophysiology. The present study describes the contributions of Cl- and HCO3- secretion to total cyclic adenosine monophosphate (cAMP)-stimulated electrogenic anion secretion in human duodenal enteroid monolayers and the relevant changes after differentiation. METHODS: Human duodenal enteroids derived from 4 donors were grown as monolayers and differentiated by a protocol that includes the removal of Wnt3A, R-spondin1, and SB202190 for 5 days. The messenger RNA level and protein expression of selected ion transporters and carbonic anhydrase isoforms were determined by quantitative real-time polymerase chain reaction and immunoblotting, respectively. Undifferentiated and differentiated enteroid monolayers were mounted in the Ussing chamber/voltage-current clamp apparatus, using solutions that contained as well as lacked Cl- and HCO3-/CO2, to determine the magnitude of forskolin-induced short-circuit current change and its sensitivity to specific inhibitors that target selected ion transporters and carbonic anhydrase(s). RESULTS: Differentiation resulted in a significant reduction in the messenger RNA level and protein expression of cystic fibrosis transmembrane conductance regulator, (CFTR) Na+/K+/2Cl- co-transporter 1 (NKCC1), and potassium channel, voltage gated, subfamily E, regulatory subunit 3 (KCNE3); and, conversely, increase of down-regulated-in-adenoma (DRA), electrogenic Na+/HCO3- co-transporter 1 (NBCe1), carbonic anhydrase 2 (CA2), and carbonic anhydrase 4 (CA4). Both undifferentiated and differentiated enteroids showed active cAMP-stimulated anion secretion that included both Cl- and HCO3- secretion as the magnitude of total active anion secretion was reduced after the removal of extracellular Cl- or HCO3-/CO2. The magnitude of total anion secretion in differentiated enteroids was approximately 33% of that in undifferentiated enteroids, primarily owing to the reduction in Cl- secretion with no significant change in HCO3- secretion. Anion secretion was consistently lower but detectable in differentiated enteroids compared with undifferentiated enteroids in the absence of extracellular Cl- or HCO3-/CO2. Inhibiting CFTR, NKCC1, carbonic anhydrase(s), cAMP-activated K+ channel(s), and Na+/K+-adenosine triphosphatase reduced cAMP-stimulated anion secretion in both undifferentiated and differentiated enteroids. CONCLUSIONS: Human enteroids recapitulate anion secretion physiology of small intestinal epithelium. Enteroid differentiation is associated with significant alterations in the expression of several ion transporters and carbonic anhydrase isoforms, leading to a reduced but preserved anion secretory phenotype owing to markedly reduced Cl- secretion but no significant change in HCO3- secretion.

A common NHE3 single-nucleotide polymorphism has normal function and sensitivity to regulatory ligands.

Na+/H+ exchanger NHE3 mediates the majority of intestinal and renal electroneutral sodium absorption. Dysfunction of NHE3 is associated with a variety of diarrheal diseases. We previously reported that the NHE3 gene (SLC9A3) has more than 400 single-nucleotide polymorphisms (SNPs) but few nonsynonymous polymorphisms. Among the latter, one polymorphism (rs2247114-G>A), which causes a substitution from arginine to cysteine at amino acid position 799 (p.R799C), is common in Asian populations. To improve our understanding of the population distribution and potential clinical significance of the NHE3-799C variant, we investigated the frequency of this polymorphism in different ethnic groups using bioinformatics analyses and in a cohort of Japanese patients with cardiovascular or renal disease. We also characterized the function of human NHE3-799C and its sensitivity to regulatory ligands in an in vitro model. NHE3-799C had an allele frequency of 29.5-57.6% in Asian populations, 11.1-23.6% in European populations, and 10.2-22.7% in African populations. PS120/FLAG-NHERF2 fibroblasts stably expressing NHE3-799C had lower total protein expression but a higher percentage of surface expression than those expressing NHE3-799R. NHE3-799C had similar basal activity to NHE3-799R and was similarly stimulated or inhibited, by serum or forskolin, respectively. Tenapanor, a small-molecule NHE3 inhibitor, dose-dependently inhibited NHE3-799R and NHE3-799C activities. The IC50 values of tenapanor for NHE3-799C and NHE3-799R were significantly different, but both were in the nanomolar range. These results suggest that NHE3-799C is a common variant enriched in Asian populations, is not associated with compromised function or abnormal regulation, and is unlikely to contribute to clinical disease.NEW & NOTEWORTHY This study reports results on the functional significance of human NHE3-799C under basal conditions and in response to regulatory ligands, including a novel NHE3 inhibitor called tenapanor. We demonstrate that NHE3-799C is a common variant of NHE3 that is enriched in Asian populations; however, in contrast to our previous studies using rabbit NHE3, its presence seems to have limited clinical significance in humans and is not associated with compromised function or abnormal transport regulation.

Benzopyrimido-pyrrolo-oxazine-dione CFTR inhibitor (R)-BPO-27 for antisecretory therapy of diarrheas caused by bacterial enterotoxins.

Secretory diarrheas caused by bacterial enterotoxins, including cholera and traveler's diarrhea, remain a major global health problem. Inappropriate activation of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel occurs in these diarrheas. We previously reported that the benzopyrimido-pyrrolo-oxazinedione (R)-BPO-27 inhibits CFTR chloride conductance with low-nanomolar potency. Here, we demonstrate using experimental mouse models and human enterocyte cultures the potential utility of (R)-BPO-27 for treatment of secretory diarrheas caused by cholera and Escherichia coli enterotoxins. (R)-BPO-27 fully blocked CFTR chloride conductance in epithelial cell cultures and intestine after cAMP agonists, cholera toxin, or heat-stable enterotoxin of E. coli (STa toxin), with IC50 down to ∼5 nM. (R)-BPO-27 prevented cholera toxin and STa toxin-induced fluid accumulation in small intestinal loops, with IC50 down to 0.1 mg/kg. (R)-BPO-27 did not impair intestinal fluid absorption or inhibit other major intestinal transporters. Pharmacokinetics in mice showed >90% oral bioavailability with sustained therapeutic serum levels for >4 h without the significant toxicity seen with 7-d administration at 5 mg/kg/d. As evidence to support efficacy in human diarrheas, (R)-BPO-27 blocked fluid secretion in primary cultures of enteroids from human small intestine and anion current in enteroid monolayers. These studies support the potential utility of (R)-BPO-27 for therapy of CFTR-mediated secretory diarrheas.-Cil, O., Phuan, P.-W., Gillespie, A. M., Lee, S., Tradtrantip, L., Yin, J., Tse, M., Zachos, N. C., Lin, R., Donowitz, M., Verkman, A. S. Benzopyrimido-pyrrolo-oxazine-dione CFTR inhibitor (R)-BPO-27 for antisecretory therapy of diarrheas caused by bacterial enterotoxins.

Perioperative Alanyl-Glutamine-Supplemented Parenteral Nutrition in Chronic Radiation Enteritis Patients With Surgical Intestinal Obstruction: A Prospective, Randomized, Controlled Study.

BACKGROUND: A prospective, randomized, controlled study was performed to evaluate the effects of perioperative alanyl-glutamine-supplemented parenteral nutrition (PN) support on the immunologic function, intestinal permeability, and nutrition status of surgical patients with chronic radiation enteritis (CRE)-induced intestinal obstruction. METHODS: Patients who received 0.4 g/kg/d alanyl-glutamine and isonitrogenous PN were assigned to an alanyl-glutamine-supplemented PN (Gln-PN) group and a control group, respectively. Serum levels of alanine aminotransferase and glutamine, body fat mass (FM), immunologic function, and intestinal permeability were measured before and after surgery. RESULTS: Serum glutamine levels of the Gln-PN group significantly exceeded that of the control group (P < .001; Gln-PN, baseline 460.7 ± 42.5 vs 523.3 ± 48.6 µmol/L on postoperative day 14 [POD14], P < .001; control, baseline 451.9 ± 44.0 vs 453.8 ± 42.3 µmol/L on POD14, P = .708). Lactulose/mannitol ratios of both groups decreased over time (Gln-PN, baseline 0.129 ± 0.0403 vs 0.024 ± 0.0107 on POD1 4; control, baseline 0.125 ± 0.0378 vs 0.044 ± 0.0126 on POD14, P < .001 in both groups). CD4/CD8-positive T-lymphocyte ratios significantly rose in both groups, with significant intergroup difference (P < .001; Gln-PN, baseline 1.36 ± 0.32 vs 1.82 ± 0.30 on POD14, P < .001; control, baseline 1.37 ± 0.25 vs 1.63 ± 0.31 on POD14, P < .001). In the Gln-PN group, FM increased from 3.68 ± 1.68 kg at baseline to 5.22 ± 1.42 kg on POD14 (P < .001). FM of control group increased from 3.84 ± 1.57 kg at baseline to 5.40 ± 1.54 kg on POD14 (P < .001). However, there were no significant intergroup differences (P = .614). CONCLUSION: Gln-PN significantly boosted the immune state and decreased the intestinal permeability of CRE patients. However, Gln-PN was not superior to standard PN in improving the nutrition state and intestinal motility of surgical patients with CRE-induced intestinal obstruction.

Human Enteroids as a Model of Upper Small Intestinal Ion Transport Physiology and Pathophysiology.

BACKGROUND & AIMS: Human intestinal crypt-derived enteroids are a model of intestinal ion transport that require validation by comparison with cell culture and animal models. We used human small intestinal enteroids to study neutral Na(+) absorption and stimulated fluid and anion secretion under basal and regulated conditions in undifferentiated and differentiated cultures to show their functional relevance to ion transport physiology and pathophysiology. METHODS: Human intestinal tissue specimens were obtained from an endoscopic biopsy or surgical resections performed at Johns Hopkins Hospital. Crypts were isolated, enteroids were propagated in culture, induced to undergo differentiation, and transduced with lentiviral vectors. Crypt markers, surface cell enzymes, and membrane ion transporters were characterized using quantitative reverse-transcription polymerase chain reaction, immunoblot, or immunofluorescence analyses. We used multiphoton and time-lapse confocal microscopy to monitor intracellular pH and luminal dilatation in enteroids under basal and regulated conditions. RESULTS: Enteroids differentiated upon withdrawal of WNT3A, yielding decreased crypt markers and increased villus-like characteristics. Na(+)/H(+) exchanger 3 activity was similar in undifferentiated and differentiated enteroids, and was affected by known inhibitors, second messengers, and bacterial enterotoxins. Forskolin-induced swelling was completely dependent on cystic fibrosis transmembrane conductance regulator and partially dependent on Na(+)/H(+) exchanger 3 and Na(+)/K(+)/2Cl(-) cotransporter 1 inhibition in undifferentiated and differentiated enteroids. Increases in cyclic adenosine monophosphate with forskolin caused enteroid intracellular acidification in HCO3(-)-free buffer. Cyclic adenosine monophosphate-induced enteroid intracellular pH acidification as part of duodenal HCO3(-) secretion appears to require cystic fibrosis transmembrane conductance regulator and electrogenic Na(+)/HCO3(-) cotransporter 1. CONCLUSIONS: Undifferentiated or crypt-like, and differentiated or villus-like, human enteroids represent distinct points along the crypt-villus axis; they can be used to characterize electrolyte transport processes along the vertical axis of the small intestine. The duodenal enteroid model showed that electrogenic Na(+)/HCO3(-) cotransporter 1 might be a target in the intestinal mucosa for treatment of secretory diarrheas.

Early versus delayed enteral feeding in patients with abdominal trauma: a retrospective cohort study.

PURPOSE: Early enteral feeding within 24-48 h of intensive care unit admission is recommended for critically ill patients. This study aimed to determine if early enteral feeding could be safely implemented with purported benefits in patients with abdominal trauma. METHODS: A retrospective cohort study was performed that included 88 adult patients with abdominal trauma. Patients receiving enteral feeding within 72 h of surgical intensive care unit (SICU) admission (early-initiation group, n = 28) were compared to those receiving enteral feeding later (delayed-initiation group, n = 60). RESULTS: The two groups were comparable in demographic characteristics and injury severity. There were no differences in feeding intolerance (53.6 vs. 43.3%, p = 0.37) and mortality at 28 days (0 vs. 5%, p = 0.55) between the early-initiation group and the delayed-initiation group. However, patients in the early-initiation group had fewer infectious complications (17.9 vs. 40 %, p = 0.04) and shorter length of stay in SICU and hospital (p < 0.01) than patients in the delayed-initiation group. CONCLUSIONS: Early enteral feeding administered within 72 h of SICU admission was associated with improved clinical outcomes without risk of increasing feeding intolerance in patients with abdominal trauma. Our results support the implementation of early enteral feeding in abdominal trauma management.

Sorting nexin 27 regulates basal and stimulated brush border trafficking of NHE3.

Sorting nexin 27 (SNX27) contains a PDZ domain that is phylogenetically related to the PDZ domains of the NHERF proteins. Studies on nonepithelial cells have shown that this protein is located in endosomes, where it regulates trafficking of cargo proteins in a PDZ domain-dependent manner. However, the role of SNX27 in trafficking of cargo proteins in epithelial cells has not been adequately explored. Here we show that SNX27 directly interacts with NHE3 (C-terminus) primarily through the SNX27 PDZ domain. A combination of knockdown and reconstitution experiments with wild type and a PDZ domain mutant (GYGF → GAGA) of SNX27 demonstrate that the PDZ domain of SNX27 is required to maintain basal NHE3 activity and surface expression of NHE3 in polarized epithelial cells. Biotinylation-based recycling and degradation studies in intestinal epithelial cells show that SNX27 is required for the exocytosis (not endocytosis) of NHE3 from early endosome to plasma membrane. SNX27 is also required to regulate the retention of NHE3 on the plasma membrane. The findings of the present study extend our understanding of PDZ-mediated recycling of cargo proteins from endosome to plasma membrane in epithelial cells.

Goal-directed transfusion protocol via thrombelastography in patients with abdominal trauma: a retrospective study.

INTRODUCTION: The optimal transfusion protocol remains unknown in the trauma setting. This retrospective cohort study aimed to determine if goal-directed transfusion protocol based on standard thrombelastography (TEG) is feasible and beneficial in patients with abdominal trauma. METHODS: Sixty adult patients with abdominal trauma who received 2 or more units of red blood cell transfusion within 24 hours of admission were studied. Patients managed with goal-directed transfusion protocol via TEG (goal-directed group) were compared to patients admitted before utilization of the protocol (control group). RESULTS: There were 29 patients in the goal-directed group and 31 in the control group. Baseline parameters were similar except for higher admission systolic blood pressure in the goal-directed group than the control group (121.8 ± 23.1 mmHg vs 102.7 ± 26.5 mmHg, p < 0.01). At 24 h, patients in the goal-directed group had shorter aPTT compared to patients in the control group (39.2 ± 16.3 s vs 58.6 ± 36.6 s, p = 0.044). Administration of total blood products at 24 h appeared to be fewer in the goal-directed group than the control group (10.2 [7.0-43.1]U vs 14.8 [8.3-37.6]U, p = 0.28), but this was not statistically significant. Subgroup analysis including patients with ISS ≥16 showed that patients in the goal-directed group had significantly fewer consumption of total blood products than patients in the control group (7[6.1, 47.0]U vs 37.6[14.5, 89.9]U, p = 0.015). No differences were found in mortality at 28d, length of stay in intensive care unit and hospital between the two groups. CONCLUSIONS: Goal-directed transfusion protocol via standard TEG was achievable in patients with abdominal trauma. The novel protocol, compared to conventional transfusion management, has the potential to decrease blood product utilization and prevent exacerbation of coagulation function.

Development of two enteroatmospheric fistulae after split-thickness skin grafting: a case report.

An enteroatmospheric fistula is a devastating complication in the open abdomen. Usually the fistula forms before the completion of split-thickness skin graft surgery. A 35-year-old woman admitted with pancreatic and liver injuries, and postoperative sepsis underwent open abdomen treatment and developed two enteroatmospheric fistulae 14 days after split-thickness skin grafting. The complication was believed to have occurred as a result of multiple surgical manipulations for intra-abdominal hemorrhage and skin graft dressing changes. One fistula, measuring 0.5 cm in diameter, was managed using a tailored 20-mL syringe, secured to the surrounding tissues with ostomy paste, and a suction catheter. The other fistula, measuring 1.8 cm in diameter, required insertion of a catheter to collect the effluent. Once the effluent was controlled effectively, a second split-thickness skin graft procedure was performed to facilitate fistula management. The patient remained stable until successful fistula repair 8 months later, and she is now awaiting elective abdominal wall reconstruction. This case study is an important reminder that patients with an open abdomen, even after split-thickness skin grafting, are at risk for enteroatmospheric fistula formation. Once this severe complication occurs, effective control of fistula effluent and subsequent split-thickness skin grafting procedures are needed.