FXR deletion attenuates intestinal barrier dysfunction in murine acute intestinal inflammation.

Accumulating literature suggests that the farnesoid-X receptor (FXR), a nuclear bile acid receptor best known for its role in bile acid homeostasis, is also a potent context-dependent regulator of inflammation. FXR may thus be relevant to several intestinal disease states including inflammatory bowel disease, necrotizing enterocolitis, and sepsis. In this study, we tested the effects of FXR deletion on acute murine intestinal inflammation. We found that FXR knockout (KO) mice were protected from intestinal injury and barrier dysfunction induced by lipopolysaccharide (LPS) injection, dithizone (DI)/Klebsiella, and cecal ligation/puncture models. In the LPS model, RNA sequencing and qPCR analysis showed that this protection correlated with substantial reduction in LPS-induced proinflammatory gene expression, including lower tissue levels of Il1a, Il1b, and Tnf. Examining functional effects on the epithelium, we found that LPS-induced tight junctional disruption as assessed by internalization of ZO-1 and occludin was ameliorated in FXR KO animals. Taken together, these data suggest a role for FXR in the intestinal barrier during inflammatory injury.NEW & NOTEWORTHY Intestinal barrier failure is a hallmark in gut-origin sepsis. We demonstrate that the intestinal barriers of farnesoid-X receptor (FXR) knockout (KO) animals are protected from inflammatory insult using multiple models of acute intestinal inflammation. This protection is due to decreased inflammatory cytokine production and maintenance of tight junctional architecture seen within the KO animals. This is the first report of FXR deletion being protective to the intestinal barrier.

Clinical Characteristics of Avoidable Patient Transfers for Suspected Pediatric Appendicitis.

INTRODUCTION: Pediatric surgical care is becoming increasingly regionalized, often resulting in limited access. Interfacility transfers pose a significant financial and emotional burden to when they are potentially avoidable. Of transferred patients, we sought to identify clinical factors associated with avoidable transfers in pediatric patients with suspected appendicitis. METHODS: We performed a single-center retrospective study at an academic tertiary referral children's hospital in an urban setting. We included children who underwent interfacility transfer to our center with a transfer diagnosis of appendicitis from July 1, 2021 to June 30, 2023. Encounters were designated as either an appropriate transfer (underwent appendectomy) or an avoidable transfer (did not undergo appendectomy). Encounters treated nonoperatively for complicated appendicitis were excluded. Bivariate analysis was performed using Mann-Whitney test and chi-square tests. RESULTS: A total of 444 patients were included: 71.2% were classified as appropriate transfers and 28.8% as avoidable transfers. Patients with avoidable transfer were younger compared to those in the appropriate transfer cohort (median age 9 y, interquartile range: 7-13 versus 11 y, interquartile range: 8-14; P < 0.001). Avoidable transfers less frequently presented with the typical symptoms of fever, migratory abdominal pain, anorexia, and nausea/emesis (P = 0.005). Avoidable transfers also reported shorter symptom duration (P = 0.040) with lower median white blood cell count (P < 0.001), neutrophil percentage (P < 0.001), and C-reactive protein levels (P < 0.003). Avoidable transfers more frequently underwent repeat imaging upon arrival (42.9% versus 12.7%, P < 0.001). CONCLUSIONS: These findings highlight the importance of clinical history in children with suspected appendicitis. Younger patients without typical symptoms of appendicitis, those with a shorter duration of symptoms, and lower serum inflammatory markers may benefit from close observation without transfer.

Utility of colonic manometry in children with Hirschsprung disease.

OBJECTIVES: Abnormal motility of the residual colon has been reported in post-pull-through Hirschsprung disease (PT-HSCR) patients with persistent defecation problems. We reviewed the role of colonic manometry (CM) in the management of defecation disorders in these patients. METHODS: We retrospectively reviewed the medical record of PT-HSCR children who underwent CM for persistent symptoms of abnormal defecation. We reviewed their clinical course and its relation to CM findings. RESULTS: Thirty PT-HSCR patients underwent CM, of which five were diagnosed with transition zone pull-through and were excluded. Of the remaining 25 patients, 16 had colonic dysmotility, 8 had normal CM, and one had colonic hypermotility. In patients with dysmotility, five responded to ongoing medical management, three required surgical intervention (ileostomy), three remained symptomatic with medical management but not yet received surgical intervention, and five were lost to follow-up. In patients with normal CM, four responded to ongoing medical therapy, two required additional surgery (antegrade enema procedure), and two were lost to follow-up. The patient with hypermotility improved with adding loperamide. CONCLUSIONS: Colonic dysmotility can occur in PT-HSCR patients with persistent defecation problems. CM was helpful in delineating the degree of colonic neuromuscular dysfunction. CM results were used in conjunction with other clinical data to determine optimal management. Our findings support that medical management should first be optimized before consideration of colonic manometry and surgical interventions.

Children with large primary spontaneous pneumothoraxes may benefit from early operative intervention.

PURPOSE: The initial management of primary spontaneous pneumothoraxes (PSP) in children remains controversial, particularly regarding the timing of operative intervention. This study aimed to identify factors associated with failure of non-operative management of PSP. METHODS: A single-center, retrospective review was performed for patients presenting with PSP. Demographics and clinical predictors were collected. Patients successfully managed non-operatively were compared to failed non-operative management. Fischer exact and Mann-Whitney tests were used as appropriate. RESULTS: Fifty-seven pediatric patients were identified as having PSP. Four patients underwent initial surgical intervention, 60% (n = 34) were successfully managed non-operatively, while 33% (n = 19) failed non-operative management and underwent video-assisted thoracic surgery (VATS). Those who failed were more likely to have PSP > 2 cm on initial X-ray (79% vs. 44%, p = 0.021) and have a persistent air leak for > 48 h (47% vs 6%, p ≤ 0.001). LOS was greater in the failure group (11.5 ± 5.1 vs 3.1 ± 2.5, p ≤ 0.001) as well as higher complication rates (21% vs 0%, p = 0.013). CONCLUSION: Our findings suggest that patients presenting with PSP of > 2 cm or have a persistent air leak for > 48 h despite chest tube management are unlikely to be treated by chest tube alone and may benefit from earlier operative intervention.

Serum bile acids profiling by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and its application on pediatric liver and intestinal diseases.

Background A method for bile acid profiling measuring 21 primary and secondary bile acids in serum samples was developed and validated with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sample preparation included spiking with internal standards followed by protein precipitation, centrifugation, drying under nitrogen gas and reconstitution. Extracted samples were injected onto a Phenomenex Kinetex C18 column (150 × 4.60 mm, 2.6 µm). Methods Data was collected with LC-MS/MS operated in negative ion mode with multiple reaction monitoring (MRM) and single reaction monitoring (SRM). The analytical run time was 12 min. Results The method showed excellent linearity with high regression coefficients (>0.99) over a range of 0.05 and 25 µM for all analytes tested. The method also showed acceptable intra-day and inter-day accuracy and precision. As a proof of concept, the analytical method was applied to patients with neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), biliary atresia (BA), and necrotizing enterocolitis (NEC), and distinct bile acids profiles were demonstrated. Conclusions The method could be poised to identify possible biomarkers for non-invasive early diagnosis of these disorders.

The value of prophylactic chest tubes in tracheoesophageal fistula repair.

PURPOSE: Intraoperative chest tubes (IOCTs) can be placed during esophageal atresia/tracheoesophageal fistula (EA/TEF) repair to control pneumothoraces and detect esophageal leaks, potentially preventing the need for postoperative chest tubes (POCTs). However, data are lacking regarding IOCTs' effect. We hypothesized that IOCT placement would not reduce the risk of POCT placement and would increase hospital length of stay (LOS). METHODS: This was a single-center case-control study of type C EA/TEF patients repaired at a tertiary referral center between 2006 and 2017. Postoperative complications of patients who received IOCTs (n = 83) were compared to that of patients who did not receive IOCTs (n = 26). Patients were compared via propensity score matching. Additionally, sensitivity analyses excluding low birth weight (LBW) patients and patients undergoing delayed esophageal anastomosis were also performed. RESULTS: There was no significant difference in rates of pneumothoraces or esophageal leaks between the IOCT and no-IOCT groups, nor were either of these complications detected earlier in the IOCT group. Rates of POCT placement and mortality also did not differ between groups. IOCT patients were associated with increased hospital LOS (28 vs 15.5 days, p < 0.001) and esophageal strictures (30% vs 8%, p = 0.04) requiring a return to the operating room (RTOR). CONCLUSION: IOCTs did not improve outcomes in EA/TEF repair. IOCTs seem associated with increased LOS and ROTR for esophageal stricture, suggesting that IOCTs may not be beneficial after EA/TEF repair.

Ursodeoxycholic acid protects against intestinal barrier breakdown by promoting enterocyte migration via EGFR- and COX-2-dependent mechanisms.

The intestinal barrier is often disrupted in disease states, and intestinal barrier failure leads to sepsis. Ursodeoxycholic acid (UDCA) is a bile acid that may protect the intestinal barrier. We hypothesized that UDCA would protect the intestinal epithelium in injury models. To test this hypothesis, we utilized an in vitro wound-healing assay and a mouse model of intestinal barrier injury. We found that UDCA stimulates intestinal epithelial cell migration in vitro, and this migration was blocked by inhibition of cyclooxygenase 2 (COX-2), epidermal growth factor receptor (EGFR), or ERK. Furthermore, UDCA stimulated both COX-2 induction and EGFR phosphorylation. In vivo UDCA protected the intestinal barrier from LPS-induced injury as measured by FITC dextran leakage into the serum. Using 5-bromo-2'-deoxyuridine and 5-ethynyl-2'-deoxyuridine injections, we found that UDCA stimulated intestinal epithelial cell migration in these animals. These effects were blocked with either administration of Rofecoxib, a COX-2 inhibitor, or in EGFR-dominant negative Velvet mice, wherein UDCA had no effect on LPS-induced injury. Finally, we found increased COX-2 and phosphorylated ERK levels in LPS animals also treated with UDCA. Taken together, these data suggest that UDCA can stimulate intestinal epithelial cell migration and protect against acute intestinal injury via an EGFR- and COX-2-dependent mechanism. UDCA may be an effective treatment to prevent the early onset of gut-origin sepsis. NEW & NOTEWORTHY In this study, we show that the secondary bile acid ursodeoxycholic acid stimulates intestinal epithelial cell migration after cellular injury and also protects the intestinal barrier in an acute rodent injury model, neither of which has been previously reported. These effects are dependent on epidermal growth factor receptor activation and downstream cyclooxygenase 2 upregulation in the small intestine. This provides a potential treatment for acute, gut-origin sepsis as seen in diseases such as necrotizing enterocolitis.

Advances in paediatric gastroenterology.

Recent developments in paediatric gastrointestinal surgery have focused on minimally invasive surgery, the accumulation of high-quality clinical evidence, and scientific research. The benefits of minimally invasive surgery for common disorders like appendicitis and hypertrophic pyloric stenosis are all supported by good clinical evidence. Although minimally invasive surgery has been extended to neonatal surgery, it is difficult to establish its role for neonatal disorders such as oesophageal atresia and biliary atresia through clinical trials because of the rarity of these disorders. Advances in treatments for biliary atresia and necrotising enterocolitis have been achieved through specialisation, multidisciplinary management, and multicentre collaboration in research; similarly robust clinical evidence for other rare gastrointestinal disorders is needed. As more neonates with gastrointestinal diseases survive into adulthood, their long-term sequelae will also need evidence-based multidisciplinary care. Identifying cures for long-term problems of a complex developmental anomaly such as Hirschsprung's disease will rely on unravelling its pathogenesis through genetics and the development of stem-cell therapy.

Liquid chromatography-mass spectroscopy in the diagnosis of biliary atresia in children with hyperbilirubinemia.

BACKGROUND: Biliary atresia (BA) is difficult to distinguish from other causes of cholestasis. We evaluated the use of liquid chromatography-mass spectroscopy (LC-MS) and bile acid profiles in the rapid, noninvasive diagnosis of BA. MATERIALS AND METHODS: Following Institutional Animal Care and Use Committee and Institutional Review Board approval, we used LC-MS to measure 26 bile acids in serum and stool samples from experimental models of BA and in urine, stool, and serum samples from non-cholestatic and cholestatic human infants. RESULTS: We first evaluated the utility of LC-MS to distinguish bile acid profiles between sham, bile duct ligation, and 3,5-diethoxycarbonyl-1,4-dihydrocollidine mouse models of BA. Serum bile acids were significantly higher and stool bile acids were significantly lower in experimental BA. Next, we evaluated samples from non-cholestatic, cholestatic non-BA, and BA infants. There was no significant difference between cholestatic non-BA and BA stool and urine samples. However, primary bile acids were significantly higher in BA versus cholestatic non-BA samples (128.1 ± 14.2 versus 61.2 ± 20.5 µM). In addition, the primary, conjugated bile acids glycochenodeoxycholic acid and taurochenodeoxycholic acid were significantly elevated in BA compared with cholestatic non-BA serum samples. Using a receiver operating characteristic curve, we found that a serum glycochenodeoxycholic acid concentration of 30 µM had a sensitivity of 100%, specificity of 83.3%, positive predictive value of 88.9%, and negative predictive value of 100% in the diagnosis of BA. CONCLUSIONS: Our data indicate that bile acid patterns can be used to distinguish experimental and human BA from non-cholestatic and, more importantly, cholestatic disease. This suggests that LC-MS may be useful in the accurate, rapid, and non-invasive diagnosis of BA.

Re-evaluation of liver transaminase cutoff for CT after pediatric blunt abdominal trauma.

PURPOSE: Current guidelines for computed tomography (CT) after blunt trauma were developed to capture all intra-abdominal injuries (IAI). We hypothesize that current AST/ALT guidelines are too low leading to unnecessary CT scans for children after blunt abdominal trauma (BAT). METHODS: Patients who received CT of the abdomen after blunt trauma at our Level I Pediatric Trauma Center were stratified into a high risk (HR) (liver/spleen/kidney grade ≥III, hollow viscous, or pancreatic injuries) and low risk (LR) (liver/kidney/spleen injuries grade ≤II, or no IAI) groups. RESULTS: 247 patients were included. Of the 18 patients in the HR group, two required surgery (splenectomy and sigmoidectomy). Transfusion was required in 30% of grade III and 50% of grade IV injuries. Eleven (5%) patients in LR group were transfused for indications other than IAI, and none were explored surgically. Both AST (r = 0.44, p < 0.001) and ALT (r = 0.43, p < 0.001) correlated with grade of liver injury. Using an increased threshold of AST/ALT, 400/200 had a negative predictive value of 96% in predicting the presence of HR liver injuries. CONCLUSION: The current cutoff of liver enzymes leads to over-identification of LR injuries. Consideration should be given to an approach that aims to utilize CT in pediatric BAT that identifies clinically HR injury.

Bile acids regulate intestinal cell proliferation by modulating EGFR and FXR signaling.

Bile acids (BAs) are synthesized in the liver and secreted into the intestine. In the lumen, enteric bacteria metabolize BAs from conjugated, primary forms into more toxic unconjugated, secondary metabolites. Secondary BAs can be injurious to the intestine and may contribute to disease. The epidermal growth factor receptor (EGFR) and the nuclear farnesoid X receptor (FXR) are known to interact with BAs. In this study we examined the effects of BAs on intestinal epithelial cell proliferation and investigated the possible roles for EGFR and FXR in these effects. We report that taurine-conjugated cholic acid (TCA) induced proliferation, while its unconjugated secondary counterpart deoxycholic acid (DCA) inhibited proliferation. TCA stimulated phosphorylation of Src, EGFR, and ERK 1/2. Pharmacological blockade of any of these pathways or genetic ablation of EGFR abrogated TCA-stimulated proliferation. Interestingly, Src or EGFR inhibitors eliminated TCA-induced phosphorylation of both molecules, suggesting that their activation is interdependent. In contrast to TCA, DCA exposure diminished EGFR phosphorylation, and pharmacological or siRNA blockade of FXR abolished DCA-induced inhibition of proliferation. Taken together, these results suggest that TCA induces intestinal cell proliferation via Src, EGFR, and ERK activation. In contrast, DCA inhibits proliferation via an FXR-dependent mechanism that may include downstream inactivation of the EGFR/Src/ERK pathway. Since elevated secondary BA levels are the result of specific bacterial modification, this may provide a mechanism through which an altered microbiota contributes to normal or abnormal intestinal epithelial cell proliferation.

A Standardized Post-gastrostomy Feeding Protocol for Pediatric Patients Reduces Time to Postoperative Goal Feeding Volume.

BACKGROUND: Gastrostomy creation is a common pediatric surgical procedure, but the time to initiation of feeds and to goal feeding volumes postoperatively varies greatly. Delays in reaching goal feeding volumes promote malnutrition and may prolong hospital length of stay. We hypothesized that implementing an accelerated, standardized post-gastrostomy feeding protocol would allow patients to reach goal feeding volumes sooner, without increasing postoperative complications. METHODS: We conducted a retrospective cohort study of children who underwent gastrostomy tube placement between 1/1/2022 and 11/30/2023. The feeding protocol was implemented on 11/16/2022, with patients separated into pre- and post-protocol cohorts. Abstracted data included comorbidities, time to initiation of enteral feeds, time to goal feeding volume, and postoperative complications. RESULTS: 322 patients were included: 166 pre-protocol and 156 post-protocol. The post-protocol cohort had a greater proportion of patients with gastrointestinal and/or cardiac comorbidities (P < .001). Through the protocol, postoperative enteral feeds were initiated significantly faster (5.4 hrs [IQR 43-7.7] vs 7.0 hrs [IQR 5.6-14.3]; P < .001). The post-protocol cohort also achieved goal feeding volumes sooner (12.8 hrs [IQR 9.1-25.3] vs 26.3 hrs [IQR 21.6-38.9]; P < .001). Postoperative complication rates did not differ between cohorts. Sub-analysis of children with complex cardiac conditions also demonstrated faster time to goal nutrition without an associated increase in postoperative events. DISCUSSION: These findings demonstrate that our accelerated post-gastrostomy feeding protocol was effective in achieving goal enteral nutrition earlier without increasing postoperative adverse outcomes. This protocol may be used by other centers to safely expedite time to goal enteral feeds in children postoperatively.

Evaluation of Postoperative Outcomes After Enterostomy Closure in Low Body Weight Infants: A Multi-Center Retrospective Analysis.

BACKGROUND: The minimum weight for enterostomy closure (EC) in infants remains debated with the current acceptable cut-off of >2 kg. As enterostomy-related complications or high enterostomy output (>30cc/kg/d) may prohibit a premature infant from reaching 2 kg, additional data is needed to evaluate the safety of EC in infants <2 kg. The objective of this study was to evaluate postoperative outcomes in low body weight (<2 kg) infants undergoing EC compared to larger infants. METHODS: We performed a multi-center retrospective analysis from 1/1/2012-12/31/2022 of all infants (age <1 year) who were <4 kg at time of EC. Primary outcomes included postoperative complications and 30-day mortality. Non-parametric analysis was performed using the Kruskal-Wallis one-way analysis of variance and chi-square tests. Univariable logistic regression was performed to identify factors associated with postoperative complications. RESULTS: Of 92 infants, 15 infants (16.3%) underwent EC at <2 kg, 16 (17.4%) at 2-2.49 kg, 31 (33.7%) at 2.5-2.99 kg, and 30 (32.6%) at ≥3 kg. Infants <2 kg at time of EC exhibited higher rates of hyperbilirubinemia (P = .030), neurologic comorbidities (P = .030), and high enterostomy output (P = .041). There was no difference in postoperative complications (P = .460) or 30-day mortality (P = .460) between the <2 kg group and larger weight groups. Low body weight was not associated with an increased risk for developing a postoperative complication (OR: 1.001, 95% CI: 1.001-1.001; P = .032). CONCLUSION: Our findings suggest that EC in infants <2 kg may be safe with comparable postoperative outcomes to larger weight infants. Thus, the timing of EC should be based on the infant's physiologic status, in contrast to a predetermined minimum weight cut-off.

Recent developments in Hirschsprung's-associated enterocolitis.

Hirschsprung's-associated enterocolitis (HAEC) continues to be a significant source of morbidity for patients with Hirschsprung's disease (HD). New clinical and histologic classification systems for HAEC will improve consistency between reports and increase the ability to compare outcomes. A complete understanding of disease pathogenesis is lacking, but evidence suggests that the intestinal microbiota may play a role in the development of HD and HAEC. The benefits of adjunctive therapies, such as anal dilations and botulinum toxin to reduce the incidence of HAEC following corrective endorectal pull-through, remain controversial. Finally, new clinical data have identified an association between HAEC and inflammatory bowel disease and will likely lead to further genetic studies to elucidate the connection between these two disease processes.

Isolated ruptured appendicitis presenting as pneumatosis intestinalis in a premature neonate.

We report a novel case of ruptured appendicitis in a premature neonate which radiographically mimicked necrotizing enterocolitis with free intraperitoneal air. On exploratory laparotomy, both the large and small intestines were normal.

Primary Adrenal Malignant Rhabdoid Tumor in a 14-Year-Old Female: A Case Report and Literature Review.

Malignant rhabdoid tumor (MRT) is a rare, SWItch/sucrose nonfermentable-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 (SMARCB1)-deficient, aggressive tumor, occurring predominantly in children below 3 years of age. Primary adrenal MRT is extremely rare, with only 3 cases reported in the literature. A previously healthy 14-year-old female presented with left upper quadrant/epigastric abdominal pain. Imaging studies revealed an 8.0 × 8.0 × 6.5 cm, heterogeneous, partially enhancing mass along the superior margin of the left kidney encasing the adrenal gland. Surgical resection of the tumor revealed a hypercellular heterogeneous neoplasm arising from the adrenal gland. It was composed predominantly of primitive small round blue cells with focal true rosettes and areas of vague glandular epithelial differentiation and chondroid differentiation. Classic rhabdoid-type cytoplasmic inclusions were focally present. Mitoses, tumor necrosis, and hemorrhage were readily seen. Tumor cells showed complete loss of SMARCB1 (INI1) nuclear staining, demonstrated strong, and diffuse positivity for glypican 3, patchy positivity for CD99, cytokeratin, Sal-like protein 4, Lin-28 homolog A, epithelial membrane antigen, and S100. Molecular studies revealed biallelic frameshift mutations in the SMARCB1 gene (c.673delG and c.683dupT) without pathogenic copy number aberrations. The histologic, immunohistochemical, and molecular findings support a diagnosis of MRT. The unusual age, location, and mutations of this case expand the clinicopathologic and molecular spectrum of MRT.

Combined endoscopic and laparoscopic approach to a gastroesophageal tumor.

BACKGROUND AND OBJECTIVES: Smooth muscle tumors of the stomach, especially when benign, are a common clinical entity and can represent a therapeutic challenge. Classically the removal of such a tumor requires open laparotomy. We sought to perform this surgery utilizing minimally invasive technology. METHODS: We describe a minimally invasive technique combining laparoscopy with endoscopy to remove a sub-mucosal leiomyoma at the gastroesophageal junction. RESULTS: A 3.3-cm smooth muscle tumor of the gastroesophageal junction was removed completely and safely with the described procedure and thus saved the patient from requiring a laparotomy. CONCLUSION: Minimally invasive techniques can be used in combination to tackle difficult problems in general surgery leading to shorter hospital stays and improved patient satisfaction.

The Pathophysiology of Farnesoid X Receptor (FXR) in the GI Tract: Inflammation, Barrier Function and Innate Immunity.

The Farnesoid-X Receptor, FXR, is a nuclear bile acid receptor. Its originally described function is in bile acid synthesis and regulation within the liver. More recently, however, FXR has been increasingly appreciated for its breadth of function and expression across multiple organ systems, including the intestine. While FXR's role within the liver continues to be investigated, increasing literature indicates that FXR has important roles in responding to inflammation, maintaining intestinal epithelial barrier function, and regulating immunity within the gastrointestinal (GI) tract. Given the complicated and multi-factorial nature of intestinal barrier dysfunction, it is not surprising that FXR's role appears equally complicated and not without conflicting data in different model systems. Recent work has suggested translational applications of FXR modulation in GI pathology; however, a better understanding of FXR physiology is necessary for these treatments to gain widespread use in human disease. This review aims to discuss current scientific work on the role of FXR within the GI tract, specifically in its role in intestinal inflammation, barrier function, and immune response, while also exploring areas of controversy.