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.

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.

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 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.

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.

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.

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.

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.

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.

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.

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.

Clinical implications of maternal-fetal cellular trafficking.

Maternal-fetal cellular trafficking (MFCT) is the bidirectional passage of cells that results in the presence of fetal cells in the mother and maternal cells in the fetus. This naturally occurring biological phenomenon has been implicated in the pathogenesis of autoimmune diseases in both mothers and children. However, MFCT may also have beneficial consequences in establishing and maintaining maternal-fetal tolerance and may have long-term consequences for transplantation tolerance. There is also evidence that trafficking is altered during pregnancy complications and fetal intervention. An improved understanding of cellular trafficking during pregnancy will lead to progress in multiple fields including autoimmunity, transplantation, and fetal surgery.

The diagnosis and management of intradiaphragmatic extralobar pulmonary sequestrations: a report of 4 cases.

BACKGROUND/PURPOSE: Intradiaphragmatic extralobar pulmonary sequestrations (IDEPSs) are a rare subset of bronchopulmonary sequestrations (BPS). We report the largest series of patients with IDEPS and describe the diagnostic and operative challenges associated with this condition. METHODS: We retrospectively reviewed our experience with fetal and pediatric BPS from 1995 to 2010 to identify patients with IDEPS. RESULTS: We identified 27 patients with BPS and 4 patients in whom the masses were within the diaphragm. In 1 patient, the prenatal ultrasound correctly identified the mass as being within the diaphragm itself, whereas the remaining cases were thought to be intraabdominal or had discordant preoperative imaging findings. The diagnosis of an IDEPS proved challenging to make prospectively using prenatal ultrasound, computed tomography, or magnetic resonance imaging. All patients underwent attempted resection. Two cases required a combined laparoscopic and thoracoscopic approach to accurately localize the mass. The postoperative recovery of these patients was uneventful. CONCLUSIONS: We present the largest reported experience of IDEPS. Because preoperative imaging studies cannot always determine whether a sequestration is intraabdominal, intrathoracic, or intradiaphragmatic, operative planning may pose a challenge. However, the use of minimally invasive approaches can allow exploration of both the thoracic and abdominal cavities with low morbidity.

In utero hematopoietic cell transplantation for the treatment of congenital anomalies.

In utero hematopoietic cell transplantation (IUHCTx) is a promising strategy for the treatment of common hematopoietic disorders and for inducing immune tolerance in the fetus. Although the efficacy of IUHCTx has been demonstrated in multiple small and large animal models, the clinical application of this technique in humans has had limited success. Recent studies in mice have demonstrated that the maternal immune system plays a critical role in limiting engraftment in the fetus. This article reviews the therapeutic rationale of IUHCTx, potential barriers to its applications, and recent experimental strategies to improve its clinical success.

Alterations in maternal-fetal cellular trafficking after fetal surgery.

BACKGROUND/PURPOSE: Bidirectional trafficking of cells between the mother and the fetus is routine in pregnancy and a component of maternal-fetal tolerance. Changes in fetal-to-maternal cellular trafficking have been reported in prenatal complications, but maternal-to-fetal trafficking has never been studied in the context of fetal intervention. We hypothesized that patients undergoing open fetal surgery would have altered maternal-fetal cellular trafficking. METHODS: Cellular trafficking was analyzed in patients with myelomeningocele (MMC) who underwent open fetal surgical repair (n = 5), patients with MMC who had routine postnatal repair (n = 6), and healthy control healthy patients (n = 9). As an additional control for the fetal operation, trafficking was also analyzed in patients who were delivered by an ex utero intrapartum treatment procedure (n = 6). Microchimerism in maternal and cord blood was determined using quantitative real-time polymerase chain reaction for nonshared alleles. RESULTS: Maternal-to-fetal trafficking was significantly increased in patients who underwent open fetal surgery for MMC compared with healthy controls, patients who underwent postnatal MMC repair, and patients who underwent ex utero intrapartum treatment. There were no differences in fetal-to-maternal cell trafficking among groups. CONCLUSION: Patients undergoing open fetal surgery for MMC have elevated levels of maternal microchimerism. These results suggest altered trafficking and/or increased proliferation of maternal cells in fetal blood and may have important implications for preterm labor.

Long-term outcomes after fetal therapy for congenital high airway obstructive syndrome.

BACKGROUND/PURPOSE: Congenital high airway obstructive syndrome (CHAOS) is a rare and devastating condition that is uniformly fatal without fetal intervention. We sought to describe fetal treatment and long-term outcomes of CHAOS at a single referral center. METHODS: The medical records of patients with fetal CHAOS evaluated at our center between 1993 and 2011 were reviewed. Maternal history, radiographic findings, antenatal management, and postnatal outcomes were compared. RESULTS: Twelve fetuses with CHAOS were identified. Eleven had concomitant hydrops at diagnosis. Six were electively terminated, and 2 had intra- or peripartum demise. Four patients underwent fetal intervention. Two underwent delivery via ex utero intrapartum treatment (EXIT) procedure with tracheostomy placement only, and 2 underwent fetal bronchoscopy with attempted wire tracheoplasty followed by EXIT with tracheostomy at delivery. All 4 patients who underwent EXIT were alive at last follow-up. One patient was ventilator and tracheostomy free and feeding by mouth. CONCLUSION: Long-term and tracheostomy-free survival is possible with appropriate fetal intervention even in the presence of hydrops. Fetal intervention earlier in pregnancy may improve long-term outcomes, but patient selection for intervention remains challenging. Magnetic resonance imaging may help select those patients for whom fetal intervention before EXIT delivery may be beneficial.

The maternal immune response inhibits the success of in utero hematopoietic cell transplantation.

In utero hematopoietic cell transplantation (IUHCTx) is a promising strategy for the treatment of congenital stem cell disorders. Despite the purported immaturity of the fetal immune system, the clinical success of this strategy has been limited by poor engraftment of transplanted cells. The fetal host immune system is thought to be the major barrier to achieving successful IUHCTx. Since the fetal immune system is immature, however, we hypothesized that the maternal immune response may instead pose the true barrier to IUHCTx. We have demonstrated that maternal T cells traffic into the fetus after allogeneic in utero transplantation and that these lymphocytes play a critical role in limiting engraftment. Furthermore, we have shown that MHC matching the donor cells to the mother improves engraftment in the unmatched fetus. These results help renew interest in using the fetal environment to treat patients with congenital stem cell disorders.

Dynamic tracheal occlusion improves lung morphometrics and function in the fetal lamb model of congenital diaphragmatic hernia.

BACKGROUND: Congenital diaphragmatic hernia (CDH) is associated with significant neonatal morbidity and mortality. Although prenatal complete tracheal occlusion (cTO) causes hypoplastic CDH lungs to enlarge, improved lung function has not been demonstrated. Furthermore, cTO interferes with the dynamic pressure change and fluid flow associated with fetal breathing. PURPOSE: The purpose of the study was to assess a novel dynamic tracheal occlusion (dTO) device that preserves pressure changes and fluid flow. METHODS: In this pilot study, CDH was created in fetal lambs at 65 days of gestational age (GA). At 110 days GA, a cTO device (n = 3) or a dTO device (n = 4) was placed in the fetal trachea. At 135 days GA, lambs were delivered and resuscitated. Unoperated lamb co-twins (n = 5), sham thoracotomy lambs (n = 2), and untreated CDH lambs (n = 3) served as controls. RESULTS: Tracheal opening pressure, lung volume, lung fluid total protein, and phospholipid were significantly higher in the cTO group than in the dTO and unoperated control groups. Maximal oxygenation and lung compliance were significantly lower in the cTO group when compared with the unoperated control and dTO groups. CONCLUSION: Preliminary results suggest that in the fetal lamb CDH model, dTO restores normal lung morphometrics and function, whereas cTO leads to enlarged but less functional lungs.

A mouse model of in utero transplantation.

The transplantation of stem cells and viruses in utero has tremendous potential for treating congenital disorders in the human fetus. For example, in utero transplantation (IUT) of hematopoietic stem cells has been used to successfully treat patients with severe combined immunodeficiency. In several other conditions, however, IUT has been attempted without success. Given these mixed results, the availability of an efficient non-human model to study the biological sequelae of stem cell transplantation and gene therapy is critical to advance this field. We and others have used the mouse model of IUT to study factors affecting successful engraftment of in utero transplanted hematopoietic stem cells in both wild-type mice and those with genetic diseases. The fetal environment also offers considerable advantages for the success of in utero gene therapy. For example, the delivery of adenoviral, adeno-associated viral, retroviral, and lentiviral vectors into the fetus has resulted in the transduction of multiple organs distant from the site of injection with long-term gene expression. in utero gene therapy may therefore be considered as a possible treatment strategy for single gene disorders such as muscular dystrophy or cystic fibrosis. Another potential advantage of IUT is the ability to induce immune tolerance to a specific antigen. As seen in mice with hemophilia, the introduction of Factor IX early in development results in tolerance to this protein. In addition to its use in investigating potential human therapies, the mouse model of IUT can be a powerful tool to study basic questions in developmental and stem cell biology. For example, one can deliver various small molecules to induce or inhibit specific gene expression at defined gestational stages and manipulate developmental pathways. The impact of these alterations can be assessed at various timepoints after the initial transplantation. Furthermore, one can transplant pluripotent or lineage specific progenitor cells into the fetal environment to study stem cell differentiation in a non-irradiated and unperturbed host environment. The mouse model of IUT has already provided numerous insights within the fields of immunology, and developmental and stem cell biology. In this video-based protocol, we describe a step-by-step approach to performing IUT in mouse fetuses and outline the critical steps and potential pitfalls of this technique.