Index admission cholecystectomy for acute cholecystitis reduces 30-day readmission rates in pediatric patients.

BACKGROUND: Adult patients with cholecystitis who do not undergo cholecystectomy on index admission have worse outcomes, however, there is a paucity of data of the role of cholecystectomy during index hospitalization in the pediatric population. Our aim was to determine outcomes and readmission rates among pediatric patients with cholecystitis who underwent index cholecystectomy versus those who did not. METHODS: We performed a retrospective study of pediatric (< 18 years old) admitted with acute cholecystitis (AC) requiring hospitalization using the 2018 National Readmission Database (NRD). Exclusion criteria included age ≥ 18 years and death on index admission. Multivariable logistic regression was performed to identify factors associated with 30-day readmissions. RESULTS: We identified 550 unique index acute cholecystitis admissions. Mean age was 14.6 ± 3.0 years. Majority of patients were female (n = 372, 67.6%). Index cholecystectomy was performed in (n = 435, 79.1%) of cases. Thirty-day readmission rate was 2.8% in patients who underwent index cholecystectomy and 22.6% in those who did not (p < 0.001). On multivariable analysis, patients who did not undergo index cholecystectomy had higher odds of 30-day readmission than those who did not (OR 10.66, 95% CI 5.06-22.45, p < 0.001). Female patients also had higher odds of 30-day readmission compared to males (OR 3.37, 95% CI 1.31-8.69). CONCLUSIONS: Patients who did not undergo index cholecystectomy had over tenfold increase in odds of 30-day readmission. Further research is required to understand the barriers to index cholecystectomy despite society recommendations and clear clinical benefit.

The need for early Kasai portoenterostomy: a Western Pediatric Surgery Research Consortium study.

PURPOSE: The purpose of this study was to investigate factors impacting transplant-free survival among infants with biliary atresia. METHODS: A multi-institutional, retrospective cohort study was performed at nine tertiary-level children's hospitals in the United States. Infants who underwent Kasai portoenterostomy (KP) from January 2009 to May 2017 were identified. Clinical characteristics included age at time of KP, steroid use, surgical approach, liver pathology, and surgeon experience. Likelihood of transplant-free survival (TFS) was evaluated using logistic regression, adjusting for patient and surgeon-level factors. Secondary outcomes at 1 year included readmission, cholangitis, reoperation, mortality, and biliary clearance. RESULTS: Overall, 223 infants underwent KP, and 91 (40.8%) survived with their native liver. Mean age at surgery was 63.9 days (± 24.7 days). At 1 year, 78.5% experienced readmission, 56.9% developed cholangitis, 3.8% had a surgical revision, and 5 died. Biliary clearance at 3 months was achieved in 76.6%. Controlling for patient and surgeon-level factors, each additional day of age toward operation was associated with a 2% decrease in likelihood of TFS (OR 0.98, 95% CI 0.97-0.99). CONCLUSION: Earlier surgical intervention by Kasai portoenterostomy at tertiary-level centers significantly increases likelihood for TFS. Policy-level interventions to facilitate early screening and surgical referral for infants with biliary atresia are warranted to improve outcomes.

Congenital superior mesenteric artery aneurysm in a 6-week-old infant presenting with upper gastrointestinal bleeding.

Visceral artery aneurysms are rare in infants and children. The majority of cases are caused by genetic syndromes, trauma, or infection. Although the majority of aneurysms are asymptomatic, visceral artery aneurysms can present with abdominal pain, nausea/vomiting, or rupture. Aneurysm rupture can manifest as hemodynamic instability and/or gastrointestinal bleeding. We present the case of a congenital idiopathic aneurysm of the superior mesenteric artery in a 6-week-old infant who presented with gastrointestinal bleeding. We report a stepwise surgical approach to achieving aneurysm exclusion and thrombosis, and highlight the robust mesenteric collateral circulation that can develop in pediatric patients.

Natural history of acute pediatric iliofemoral artery thrombosis treated with anticoagulation.

OBJECTIVE: Acute iliofemoral artery thrombosis (IFAT) can occur in critically ill neonates and infants who require indwelling arterial cannulas for monitoring or as a consequence of cardiac catheterization. Guidelines suggest treatment with anticoagulation, but evidence supporting the optimal duration of therapy and the role of surveillance ultrasound is limited. The objectives of this study were to characterize the kinetics of thrombus resolution and to define an appropriate duration of anticoagulation and interval for surveillance ultrasound. METHODS: This was a single-center retrospective cohort study of pediatric patients with acute IFAT from 2011 to 2019. Medical records and vascular laboratory studies were reviewed. Patients with one or more surveillance ultrasound examinations were included. Thrombus resolution was defined as multiphasic flow throughout the index limb without evidence of echogenic intraluminal material by ultrasound. Time to resolution of thrombus was assessed using Kaplan-Meier analysis. RESULTS: Fifty-four limbs in 50 patients were identified with acute IFAT. The median age was 9.9 weeks (interquartile range, 3.1-21.7 weeks), with a median weight of 4.2 kg (interquartile range, 3.3-5.5 kg). The majority of limbs (65%) with acute IFAT presented with a diminished pedal Doppler signal, commonly after cardiac catheterization (55%). Forty-eight (89%) limbs had complete arterial occlusion on index ultrasound, and flow could not be detected below the ankle in 48%. The median number of ultrasound examinations per limb was three (range, two to seven), and 61% of limbs had a surveillance ultrasound within 7 days of diagnosis. At 14 and 30 days, 33% and 64% of patients, respectively, treated with anticoagulation had an estimated complete resolution of thrombus. Nine (17%) patients did not receive anticoagulation, and only two of these patients experienced IFAT resolution. At the time of diagnosis, one patient underwent open thrombectomy because of a contraindication to anticoagulation, and one patient was treated with thrombolysis. There were no instances of tissue loss or amputation CONCLUSIONS: Management of IFAT with anticoagulation resulted in successful short-term outcomes. Based on the observed rate of resolution, management should start with anticoagulation, followed by surveillance ultrasound at 2-week intervals. With treatment by anticoagulation, resolution can be expected to occur in one-third of patients every 2 weeks.

Fetal intervention increases maternal T cell awareness of the foreign conceptus and can lead to immune-mediated fetal demise.

Fetal interventions to diagnose and treat congenital anomalies are growing in popularity but often lead to preterm labor. The possible contribution of the maternal adaptive immune system to postsurgical pregnancy complications has not been explored. We recently showed that fetal intervention in mice increases maternal T cell trafficking into the fetus and hypothesized that this process also may lead to increased maternal T cell recognition of the foreign conceptus and subsequent breakdown in maternal-fetal tolerance. In this study, we show that fetal intervention in mice results in accumulation of maternal T cells in the uterus and that these activated cells can produce effector cytokines. In adoptive transfer experiments, maternal T cells specific for a fetal alloantigen proliferate after fetal intervention, escape apoptosis, and become enriched compared with endogenous T cells in the uterus and uterine-draining lymph nodes. Finally, we demonstrate that such activation and accumulation can have a functional consequence: in utero transplantation of hematopoietic cells carrying the fetal alloantigen leads to enhanced demise of semiallogeneic fetuses within a litter. We further show that maternal T cells are necessary for this phenomenon. These results suggest that fetal intervention enhances maternal T cell recognition of the fetus and that T cell activation may be a culprit in postsurgical pregnancy complications. Our results have clinical implications for understanding and preventing complications associated with fetal surgery such as preterm labor.

Late-onset hypertrophic pyloric stenosis with gastric outlet obstruction: case report and review of the literature.

We report late-onset hypertrophic pyloric stenosis in a 17-year-old female. She presented with abdominal pain and an episode of upper gastrointestinal hemorrhage and subsequently developed gastric outlet obstruction. Work-up revealed circumferential pyloric thickening, delayed gastric emptying, and a stenotic, elongated pyloric channel. Biopsies showed benign gastropathy, negative for Helicobacter pylori, without eosinophilic infiltrates. Botulinum toxin injection provided limited relief. Diagnostic laparoscopy confirmed the hypertrophic pylorus and we performed laparoscopic pyloromyotomy. The patient tolerated the procedure well and had complete symptom resolution at 1-year follow-up. Hypertrophic pyloric stenosis is a rare cause of gastric outlet obstruction in adolescents and may be managed successfully with laparoscopic pyloromyotomy.

Direct and indirect antigen presentation lead to deletion of donor-specific T cells after in utero hematopoietic cell transplantation in mice.

In utero hematopoietic cell transplantation (IUHCTx) is a promising method to induce donor-specific tolerance but the mechanisms of antigen presentation that educate host T cells and the relative importance of deletion vs regulation in this setting are unknown. We studied the roles of direct and indirect antigen presentation (mediated by donor- and host-derived antigen-presenting cells [APCs], respectively) in a mouse model of IUHCTx. We found that IUHCTx leads to precocious maturation of neonatal host dendritic cells (DCs) and that there is early differentiation of donor-derived DCs, even after transplantation of a stem cell source without mature APCs. We next performed allogeneic IUHCTx into donor-specific T-cell receptor transgenic mice and confirmed that both direct and indirect antigen presentation lead to clonal deletion of effector T cells in chimeras. Deletion did not persist when chimerism was lost. Importantly, although the percentage of regulatory T cells (Tregs) after IUHCTx increased, there was no expansion in Treg numbers. In wild-type mice, there was a similar deletion of effector cells without expansion of donor-specific Tregs. Thus, tolerance induction after IUHCTx depends on both direct and indirect antigen presentation and is secondary to thymic deletion, without de novo Treg induction.

Pancreatic mesenchyme regulates epithelial organogenesis throughout development.

The developing pancreatic epithelium gives rise to all endocrine and exocrine cells of the mature organ. During organogenesis, the epithelial cells receive essential signals from the overlying mesenchyme. Previous studies, focusing on ex vivo tissue explants or complete knockout mice, have identified an important role for the mesenchyme in regulating the expansion of progenitor cells in the early pancreas epithelium. However, due to the lack of genetic tools directing expression specifically to the mesenchyme, the potential roles of this supporting tissue in vivo, especially in guiding later stages of pancreas organogenesis, have not been elucidated. We employed transgenic tools and fetal surgical techniques to ablate mesenchyme via Cre-mediated mesenchymal expression of Diphtheria Toxin (DT) at the onset of pancreas formation, and at later developmental stages via in utero injection of DT into transgenic mice expressing the Diphtheria Toxin receptor (DTR) in this tissue. Our results demonstrate that mesenchymal cells regulate pancreatic growth and branching at both early and late developmental stages by supporting proliferation of precursors and differentiated cells, respectively. Interestingly, while cell differentiation was not affected, the expansion of both the endocrine and exocrine compartments was equally impaired. To further elucidate signals required for mesenchymal cell function, we eliminated ß-catenin signaling and determined that it is a critical pathway in regulating mesenchyme survival and growth. Our study presents the first in vivo evidence that the embryonic mesenchyme provides critical signals to the epithelium throughout pancreas organogenesis. The findings are novel and relevant as they indicate a critical role for the mesenchyme during late expansion of endocrine and exocrine compartments. In addition, our results provide a molecular mechanism for mesenchymal expansion and survival by identifying ß-catenin signaling as an essential mediator of this process. These results have implications for developing strategies to expand pancreas progenitors and ß-cells for clinical transplantation.

Neonatal Hepatic Myeloid Progenitors Expand and Propagate Liver Injury in Mice.

BACKGROUND: Biliary atresia (BA) is a progressive pediatric inflammatory disease of the liver that leads to cirrhosis and necessitates liver transplantation. The rapid progression from liver injury to liver failure in children with BA suggests that factors specific to the perinatal hepatic environment are important for disease propagation. Hematopoietic stem and progenitor cells (HSPCs) reside in the fetal liver and are known to serve as central hubs of inflammation. We hypothesized that HSPCs are critical for the propagation of perinatal liver injury (PLI). METHODS: Newborn BALB/c mice were injected with rhesus rotavirus (RRV) to induce PLI or with PBS as control. Livers were compared using histology and flow cytometry. To determine the effects of HSPCs on PLI, RRV-infected neonatal mice were administered anti-CD47 and anti-CD117 to deplete HSPCs. RESULTS: PLI significantly increased the number of common myeloid progenitors and the number of CD34+ hematopoietic progenitors. Elimination of HSPCs through antibody-mediated myeloablation rescued animals from PLI and significantly increased survival (RRV+isotype control 36.4% vs. RRV+myeloablation 77.8%, Chi-test = 0.003). CONCLUSIONS: HSPCs expand as a result of RRV infection and propagate PLI. Targeting of HSPCs may be useful in preventing and treating neonatal inflammatory diseases of the liver such as BA.

Advances in the Treatment of Neonatal Biliary Disease.

This article discusses current standard of care in neonatal biliary disease, particularly management of biliary atresia and choledochal cysts. It highlights surgical considerations, guidelines for adjuvant therapies, and promising therapeutic options that are under investigation.

The natural history of fetal gallstones: a case series and updated literature review.

INTRODUCTION: The incidence of fetal gallstones is estimated at 0.45% and its clinical relevance after birth remains unknown. This study aimed to describe the natural history of fetal gallstones and their clinical sequelae after birth. METHODS: We queried a database of fetuses referred for second and third trimester sonograms performed for high-risk pregnancies, and identified cases with fetal gallstones (1996-2019). Demographics, prenatal/postnatal imaging findings, and clinical sequelae were collected. A literature review was performed according to PRISMA guidelines. RESULTS: We screened approximately 200,000 obstetric sonograms; 34 fetuses were found to have cholelithiasis. The median gestational age at the time of sonogram was 35 weeks (range 22-38). Fifty-six percent were female and 11.8% were twin pregnancies with one affected fetus. Median maternal age was 28 years (range 17-42). Eight fetuses underwent postnatal imaging and 4 had persistent cholelithiasis. There was one case of in utero demise. Two patients had structural anomalies (renal and cardiac) by sonogram. A subset of 17 patients was followed long-term (range 3-20 years), and none developed clinical sequelae from cholelithiasis. DISCUSSION/CONCLUSIONS: No child developed postnatal clinical sequelae related to cholelithiasis identified in utero. Fetal cholelithiasis can be managed expectantly without follow-up imaging in asymptomatic patients.

Hepatic Ly6CLo Non-Classical Monocytes Have Increased Nr4a1 (Nur77) in Murine Biliary Atresia.

Biliary atresia (BA) is a rapidly progressive perinatal inflammatory disease, resulting in liver failure. Hepatic Ly6CLo non-classical monocytes promote the resolution of perinatal liver inflammation during rhesus rotavirus-mediated (RRV) BA in mice. In this study, we aim to investigate the effects of inflammation on the transcription factor Nr4a1, a known regulator of non-classical monocytes. Nr4a1-GFP reporter mice were injected with PBS for control or RRV within 24 h of delivery to induce perinatal liver inflammation. GFP expression on myeloid immune populations in the liver and bone marrow (BM) was quantified 3 and 14 days after injection using flow cytometry. Statistical significance was determined using a student's t-test and ANOVA, with a p-value < 0.05 for significance. Our results demonstrate that non-classical monocytes in the neonatal liver exhibit the highest mean fluorescence intensity (MFI) of Nr4a1 (Ly6CLo MFI 6344 vs. neutrophils 3611 p < 0.001; macrophages 2782; p < 0.001; and Ly6CHi classical monocytes 4485; p < 0.0002). During inflammation, hepatic Ly6CLo non-classical monocytes showed a significant increase in Nr4a1 expression intensity from 6344 to 7600 (p = 0.012), while Nr4a1 expression remained unchanged on the other myeloid populations. These findings highlight the potential of using Nr4a1 as a regulator of neonatal hepatic Ly6CLo non-classical monocytes to mitigate perinatal liver inflammation.

Single-cell analysis of hepatoblastoma identifies tumor signatures that predict chemotherapy susceptibility using patient-specific tumor spheroids.

Pediatric hepatoblastoma is the most common primary liver cancer in infants and children. Studies of hepatoblastoma that focus exclusively on tumor cells demonstrate sparse somatic mutations and a common cell of origin, the hepatoblast, across patients. In contrast to the homogeneity these studies would suggest, hepatoblastoma tumors have a high degree of heterogeneity that can portend poor prognosis. In this study, we use single-cell transcriptomic techniques to analyze resected human pediatric hepatoblastoma specimens, and identify five hepatoblastoma tumor signatures that may account for the tumor heterogeneity observed in this disease. Notably, patient-derived hepatoblastoma spheroid cultures predict differential responses to treatment based on the transcriptomic signature of each tumor, suggesting a path forward for precision oncology for these tumors. In this work, we define hepatoblastoma tumor heterogeneity with single-cell resolution and demonstrate that patient-derived spheroids can be used to evaluate responses to chemotherapy.

The Role of Myeloid Populations during Perinatal Liver Injury and Repair.

Perinatal liver inflammation can have life-threatening consequences, particularly in infants and young children. An example of a hepatic inflammatory disease during infancy is biliary atresia (BA), an obliterative cholangiopathy that rapidly progresses to hepatic fibrosis and liver failure. The aggressive nature of BA in neonates compared to the pathogenesis of inflammatory liver diseases in adults, suggests that the mechanisms responsible for restoring tissue homeostasis following inflammation are impaired in affected infants. This article reviews our recent findings demonstrating that the relative abundance of Ly6cLo non-classical monocytes promotes resolution of perinatal liver injury in a murine model of perinatal hepatic inflammation. Our research also identifies a potential co-regulatory role between neutrophils and non-classical monocytes. Further work is needed to understand how neutrophils regulate other myeloid populations during perinatal liver inflammation. Elucidating the mechanisms that govern perinatal liver injury and repair may lead to the development of immune-directed therapies that can be used to mitigate the devastating effects of diseases like BA.

Neutrophils are important for the development of pro-reparative macrophages after irreversible electroporation of the liver in mice.

Irreversible electroporation (IRE) is a non-thermal tissue ablative technology that has emerging applications in surgical oncology and regenerative surgery. To advance its therapeutic usefulness, it is important to understand the mechanisms through which IRE induces cell death and the role of the innate immune system in mediating subsequent regenerative repair. Through intravital imaging of the liver in mice, we show that IRE produces distinctive tissue injury features, including delayed yet robust recruitment of neutrophils, consistent with programmed necrosis. IRE treatment converts the monocyte/macrophage balance from pro-inflammatory to pro-reparative populations, and depletion of neutrophils inhibits this conversion. Reduced generation of pro-reparative Ly6CloF4/80hi macrophages correlates with lower numbers of SOX9+ hepatic progenitor cells in areas of macrophage clusters within the IRE injury zone. Our findings suggest that neutrophils play an important role in promoting the development of pro-reparative Ly6Clo monocytes/macrophages at the site of IRE injury, thus establishing conditions of regenerative repair.

The relative abundance of monocyte subsets determines susceptibility to perinatal hepatic inflammation.

The devastating consequences of perinatal liver inflammation contribute to a pressing need to develop therapeutics for the diseases that underly this condition. Biliary atresia (BA) is a perinatal inflammatory disease of the liver that results in obliterative cholangiopathy and rapidly progresses to liver failure, requiring transplantation. The ability to develop targeted therapies requires an understanding of the immune mechanisms that mitigate perinatal liver inflammation. This article reviews our recent findings demonstrating that in a murine model of perinatal hepatic inflammation, Ly6cLo non-classical monocytes express a pro-reparative transcriptomic profile and that the relative abundance of Ly6cLo monocytes promotes resolution of perinatal liver inflammation, rendering neonatal pups resistant to disease. We also examine the lineage relationship between monocyte subsets, reviewing data that suggests classical monocytes are a precursor for non-classical monocytes, and the alternative possibility that separate progenitors exist for each subset. Although a precursor-product relationship between classical and non-classical monocytes might exist in certain environments, we argue that they may also arise from separate progenitors, which is evident by sustained Ly6cLo non-classical monocyte expansion when Ly6cHi monocytes are absent. An improved understanding of monocyte subsets and their developmental trajectories during perinatal hepatic inflammation will provide insight into how therapies directed at controlling monocyte function may help alleviate the devastating consequences of diseases like BA.

De novo somatic mutations and KRAS amplification are associated with cholangiocarcinoma in a patient with a history of choledochal cyst.

BACKGROUND/PURPOSE: Choledochal cysts are congenital dilations of the bile ducts, and are associated with an increased risk of malignant transformation. The purpose of this study is to report the outcomes of a large series of patients with choledochal cysts and to highlight our analysis of one patient who developed malignancy after cyst resection. METHODS: We conducted a retrospective review of patients <18 years of age with a choledochal cyst who underwent surgical resection between 1995 and 2018. Molecular testing of resected choledochal cyst specimens using the UCSF500 gene panel was performed on three patients including a 3-month-old boy and a 7-year-old girl who have remained cancer-free, and a 16-year-old girl who subsequently developed cholangiocarcinoma less than two years after resection. RESULTS: One patient of the 48 included in our study developed cholangiocarcinoma after choledochal cyst resection. We observed de novo somatic mutations in TP53 and RBM10, and KRAS amplification in this patient's tumor. CONCLUSIONS: In our series, the rate of malignancy after choledochal cyst resection was low. One patient developed de novo mutations in the remnant bile ducts after cyst resection. While it is a rare occurrence, the risk of malignancy following cyst resection supports the need for lifelong surveillance. LEVEL OF EVIDENCE: IV.

Ly6cLo non-classical monocytes promote resolution of rhesus rotavirus-mediated perinatal hepatic inflammation.

Perinatal hepatic inflammation can have devastating consequences. Monocytes play an important role in the initiation and resolution of inflammation, and their diverse functions can be attributed to specific cellular subsets: pro-inflammatory or classical monocytes (Ly6cHi) and pro-reparative or non-classical monocytes (Ly6cLo). We hypothesized that inherent differences in Ly6cHi classical monocytes and Ly6cLo non-classical monocytes determine susceptibility to perinatal hepatic inflammation in late gestation fetuses and neonates. We found an anti-inflammatory transcriptional profile expressed by Ly6cLo non-classical monocytes, and a physiologic abundance of these cells in the late gestation fetal liver. Unlike neonatal pups, late gestation fetuses proved to be resistant to rhesus rotavirus (RRV) mediated liver inflammation. Furthermore, neonatal pups were rendered resistant to RRV-mediated liver injury when Ly6cLo non-classical monocytes were expanded. Pharmacologic inhibition of Ly6cLo non-classical monocytes in this setting restored susceptibility to RRV-mediated disease. These data demonstrate that Ly6cLo monocytes promote resolution of perinatal liver inflammation in the late gestation fetus, where there is a physiologic expansion of non-classical monocytes, and in the neonatal liver upon experimental expansion of these cells. Therapeutic strategies directed towards enhancing Ly6cLo non-classical monocyte function may mitigate the detrimental effects of perinatal liver inflammation.

Intrauterine umbilical cord hemorrhage with associated jejunal atresia captured by real-time ultrasound.

The presence of unexplained umbilical cord ulceration and hemorrhage has been sporadically reported in fetuses with antenatally suggested intestinal atresia. This case report illustrates a patient with spontaneous intrauterine umbilical cord hemorrhage, captured by real-time ultrasonography, in the setting of jejunal atresia with volvulus of the distal jejunal segment.