Giant Gastroschisis with Complete Liver Herniation: A Case Report of Two Patients.

INTRODUCTION: There are no reported survivors of gastroschisis with complete liver herniation. We describe a case report of two patients, one of whom survived. CASE #1: The patient was born with gastroschisis and herniation of the entire liver. Along with silo placement, the abdominal fascia was attached to an external traction system for growth. Complete closure was achieved at 5 months. Due to pulmonary hypoplasia, high-frequency ventilation was required. The patient is doing well, on a home ventilator wean, at 20 months. CASE #2: The patient was born prematurely with gastroschisis, total liver herniation, and a defect extending to the pericardium. A silo was attached to the fascia to provide growth of the abdominal cavity. The patient developed respiratory failure, diffuse anasarca, and renal failure. She died at 38 days of life. DISCUSSION: We report the first survivor of gastroschisis with complete liver herniation, contrasting it with a death of a similar case. The associated pulmonary hypoplasia may require long-term ventilation, the inflammatory response can lead to anasarca, and renal injury can occur from acute-on-chronic compartment syndrome. CONCLUSION: External fascial traction systems can help induce growth of the abdominal wall, allowing closure of the challenging abdomen. While critical care management is complex, survival is possible.

Minimally Invasive Surgical Approach for Posterior Tracheopexy to Treat Severe Tracheomalacia: Lessons Learned from Initial Case Series.

Background/Purpose: Posterior tracheopexy directly addresses membranous tracheal intrusion in severe tracheomalacia (TM). We have previously reported our experience of posterior tracheopexy through open approach in a large series of patients. This study aimed to review lessons learned from our initial series posterior tracheopexy through the video-assisted or robotic video-assisted thoracoscopic approach. Methods: We retrospectively reviewed our single-institution experience on all patients who underwent video-assisted or robotic video-assisted posterior tracheopexy for treatment of symptomatic TM between October 2016 and February 2018. Results: Ten patients underwent video-assisted (n = 4) or robotic video-assisted (n = 6) thoracoscopic posterior tracheopexy (age range: 8 months-19 years). One patient, the youngest in our cohort, had a type C esophageal atresia repair; none of the other patients had undergone prior thoracic operations. All had symptomatic TM; 1 patient with tracheostomy dependence also had severe distal bronchomalacia, including segmental airways. Postoperatively, patients were hospitalized 3-7 days, with 1-2 days for ICU observation. Improved respiratory symptoms were noted in 9/10 patients following the operation. The 1 patient with preexisting tracheostomy had reduced ventilator dependence but remained hospitalized with ongoing respiratory symptoms. Conclusions: The thoracoscopic approach for posterior tracheopexy, while challenging, can be applied to a select cohort of children with severe TM. Thoracoscopic surgery with robotic assistance can eliminate some technical limitations of the video-assisted approach by providing an easier platform for more complicated suturing angles.

Risk factors for recurrence after thoracoscopic repair of congenital diaphragmatic hernia (CDH).

PURPOSE: To identify technical modifications concerning factors that may lower the risk of recurrence following thoracoscopic repair of congenital diaphragmatic hernia (CDH). METHODS: All CDH patients who underwent thoracoscopic repair from April 2003 to September 2017 were retrospectively reviewed. Some of the more recently treated patients underwent technically modified repairs with underlay and overlay buttresses. RESULTS: Sixty-eight patients underwent thoracoscopic repair of a diaphragmatic hernia that presented either neonatally (n = 52) or beyond the neonatal period (>1 month) (n = 16). At our institution, the minimally invasive surgical approach is considered for clinically stable CDH patients, who are likely to have type A or B defects. 21 patients had a sac-type defect. Forty-seven patients with type A defect had primary closure, buttressed in 6 cases. In 21 patients, the type B defect was repaired with a patch, buttressed in 11 patients. Median follow-up was 36 months (IQR 9-45). Recurrence occurred in 13 patients (overall 19% recurrence rate); all had a neonatally presented defect (25% vs. 0%, p = 0.03). Patients with a sac-type defect had a lower recurrence rate than patients with no hernia sac (5% vs. 26%, p = 0.05). Recurrence complicated 7 of 47 (15%) patients after primary closure and 6 of 21 (29%) patients with patch repair; none of the 17 cases with buttressed repairs had a recurrence. CONCLUSIONS: Due to a higher rate of recurrence following thoracoscopic CDH repair compared to the standard open approach, we suggest a sandwich-type buttress repair with underlay and overlay components for both primary and patch repairs. LEVEL OF EVIDENCE: Level III cohort study.

Use of Learning Teams to Improve the Educational Environment of General Surgery Residency.

OBJECTIVE: Recent surgical education literature has focused on means of improving structured educational experience in residency, particularly in the context of limited working hours. In addition, prior studies have illustrated a void in training regarding leadership. Learning teams have been adopted in several medical schools with an aim to improve the educational experience. We instituted resident learning teams with a goal of improving resident education. DESIGN: In the 2015 to 2016 academic year, we implemented a team-based learning (TBL) system of 5 teams each led by 1 to 2 chief residents and containing an approximately equal number of residents from postgraduate year (PGY)1-4. The learning teams competed for points based on weekly quizzes, preparation of materials for resident teaching, and American Board of Surgery In-Training Exam (ABSITE) scores. After a full year of TBL, residents were surveyed on their view of the learning teams with respect to the educational experience in the residency with a series of Likert-type questions. Median ABSITE scores of categorical interns were compared between the 3 years after the implementation of the learning teams and the 4 years prior with a Mann-Whitney U test. SETTING: Beth Israel Deaconess Medical Center, Boston, MA; Tertiary Care Center. PARTICIPANTS: All residents from 2011 to 2018. RESULTS: After TBL implementation, median ABSITE percentile scores of PGY2-5 residents increased (35-44, p = 0.04). PGY1 scores were not significantly changed. After TBL implementation, a majority of residents agreed or strongly agreed that they studied more consistently, felt more prepared for the ABSITE, were more prepared for resident school, learned more in resident school, and that the learning teams improved the educational experience of the residency. CONCLUSIONS: Learning teams subjectively improved the educational experience in our residency and engaged residents in studying and participating. In addition, PGY2-5 ABSITE scores were significantly improved. Learning teams are a program that can be easily adopted by surgical residencies elsewhere.

Hypoxia and hypoxia inducible factors: diverse roles in liver diseases.

Hypoxia has been shown to have a role in the pathogenesis of several forms of liver disease. The hypoxia inducible factors (HIFs) are a family of evolutionarily conserved transcriptional regulators that affect a homeostatic response to low oxygen tension and have been identified as key mediators of angiogenesis, inflammation, and metabolism. In this review we summarize the evidence for a role of HIFs across a range of hepatic pathophysiology. We describe regulation of the HIFs and review investigations that demonstrate a role for HIFs in the development of liver fibrosis, activation of innate immune pathways, hepatocellular carcinoma, as well as other liver diseases in both human disease as well as murine models.

Lipopolysaccharide induces and activates the Nalp3 inflammasome in the liver.

AIM: To examine the activation of the Nalp3 inflammasome and its downstream targets following lipopolysaccharide (LPS)-induced stimulation in the liver. METHODS: Six-to-eight-week-old C57BL/6 chow fed mice were injected intraperitoneally with 0.5 µg/g bodyweight LPS and sacrificed 2, 4, 6, 18 or 24 h later. LPS-induced liver damage was confirmed by a biochemical assay to detect alanine aminotransferase (ALT) levels. To determine if LPS stimulation in the liver led to activation of the inflammasome, real-time quantitative polymerase chain reaction was used to evaluate the mRNA expression of components of the Nalp3 inflammasome. Enzyme-linked immunosorbent assays were used to determine the protein expression levels of several downstream targets of the Nalp3 inflammasome, including caspase-1 and two cytokine targets of caspase-1, interleukin (IL)-1ß and IL-18. RESULTS: We found that LPS injection resulted in liver damage as indicated by elevated ALT levels. This was associated with a significant increase in both mRNA and protein levels of the proinflammatory cytokine tumor necrosis factor (TNF)-α in the liver, as well as increased levels of TNFs in serum. We showed that LPS stimulation led to upregulation of mRNA levels in the liver for all the receptor components of the inflammasome, including Nalp3, Nalp1, pannexin-1 and the adaptor molecule apoptosis-associated speck-like, caspase recruitment domain-domain containing protein. We also found increased levels of mRNA and protein for caspase-1, a downstream target of the inflammasome. In addition, LPS challenge led to increased levels of both mRNA and protein in the liver for two cytokine targets of caspase-1, IL-1ß and IL-18. Interestingly, substantial baseline expression of pre-IL-1ß and pre-IL-18 was found in the liver. Inflammasome and caspase-1 activation was indicated by the significant increase in the active forms of IL-1ß and IL-18 after LPS stimulation. CONCLUSION: Our results show that the Nalp3 inflammasome is upregulated and activated in the liver in response to LPS stimulation.

Hepatocyte-specific hypoxia-inducible factor-1α is a determinant of lipid accumulation and liver injury in alcohol-induced steatosis in mice.

UNLABELLED: Chronic alcohol causes hepatic steatosis and liver hypoxia. Hypoxia-regulated hypoxia-inducible factor 1-α, (HIF-1α) may regulate liporegulatory genes, but the relationship of HIF-1 to steatosis remains unknown. We investigated HIF-1α in alcohol-induced hepatic lipid accumulation. Alcohol administration resulted in steatosis, increased liver triglyceride levels, and increased serum alanine aminotransferase (ALT) levels, suggesting liver injury in wild-type (WT) mice. There was increased hepatic HIF-1α messenger RNA (mRNA), protein, and DNA-binding activity in alcohol-fed mice compared with controls. Mice engineered with hepatocyte-specific HIF-1 activation (HIF1dPA) had increased HIF-1α mRNA, protein, and DNA-binding activity, and alcohol feeding in HIF1dPA mice increased hepatomegaly and hepatic triglyceride compared with WT mice. In contrast, hepatocyte-specific deletion of HIF-1α [HIF-1α(Hep(-/-) )], protected mice from alcohol- and lipopolysaccharide (LPS)-induced liver damage, serum ALT elevation, hepatomegaly, and lipid accumulation. HIF-1α(Hep(-/-) ), WT, and HIF1dPA mice had equally suppressed levels of peroxisome proliferator-activated receptor α mRNA after chronic ethanol, whereas the HIF target, adipocyte differentiation-related protein, was up-regulated in WT mice but not HIF-1α(Hep(-/-) ) ethanol-fed/LPS-challenged mice. The chemokine monocyte chemoattractant protein-1 (MCP-1) was cooperatively induced by alcohol feeding and LPS in WT but not HIF-1α(Hep(-/-) ) mice. Using Huh7 hepatoma cells in vitro, we found that MCP-1 treatment induced lipid accumulation and increased HIF-1α protein expression as well as DNA-binding activity. Small interfering RNA inhibition of HIF-1α prevented MCP-1-induced lipid accumulation, suggesting a mechanistic role for HIF-1α in hepatocyte lipid accumulation. CONCLUSION: Alcohol feeding results in lipid accumulation in hepatocytes involving HIF-1α activation. The alcohol-induced chemokine MCP-1 triggers lipid accumulation in hepatocytes via HIF-1α activation, suggesting a mechanistic link between inflammation and hepatic steatosis in alcoholic liver disease.

Mitochondrial antiviral signaling protein defect links impaired antiviral response and liver injury in steatohepatitis in mice.

UNLABELLED: Mitochondrial dysfunction is a pathogenic feature of nonalcoholic steatohepatitis (NASH). NASH complicates hepatotropic viral disease. The mitochondrial antiviral signaling protein (MAVS) is the adapter of helicase receptors involved in sensing double-stranded RNA (dsRNA). We hypothesized that impaired MAVS function may contribute to insufficient antiviral response and liver damage in steatohepatitis. We identified reduced MAVS protein levels and increased MAVS association with the proteasome subunit alpha type 7 (PSMA7) in livers from mice given a methionine-choline-deficient (MCD) diet. Decreased association of MAVS with mitochondria and increased cytosolic cytochrome c indicated mitochondrial damage in steatohepatitis. In vivo administration of the synthetic dsRNA polyinosinic:polycytidylic acid [poly(I:C)], but not lipopolysaccharide or cytidine-phosphate-guanosine-rich DNA, resulted in impaired induction of type I interferons (IFNs) and proinflammatory cytokines in steatohepatitis. Consistent with a defect in helicase receptor-induced signaling, there was loss of poly(I:C)-induced translocation of MAVS to the cytosol and decreased IFN regulatory factor 3 phosphorylation. Caspases 1 and 8, both of which cleave MAVS, were increased in MCD diet-fed mice. At baseline, steatohepatitis was associated with increased serum alanine aminotransferase (ALT), apoptosis and caspase 3 activation compared with controls. In contrast to apoptosis in controls, necrosis was induced by poly(I:C) stimulation in steatohepatitis. Hepatocyte necrosis was indicated by elevated serum high-mobility group box protein-1 and ALT and was correlated with increased expression of receptor-interacting protein 3 (RIP3), a master regulator of necrosis. Increased expression of MAVS, PSMA7, and RIP3 messenger RNA was also present in human NASH livers. CONCLUSION: Our novel findings suggest that mitochondrial damage in steatohepatitis extends to MAVS, an adapter of helicase receptors, resulting in inefficient type I IFN and inflammatory cytokine response but increased hepatocyte necrosis and RIP3 induction in response to a dsRNA viral challenge. These mechanisms may contribute to progressive liver damage and impaired viral clearance in NASH.

Interferon regulatory factor 3 and type I interferons are protective in alcoholic liver injury in mice by way of crosstalk of parenchymal and myeloid cells.

UNLABELLED: Alcoholic liver disease (ALD) features increased hepatic exposure to bacterial lipopolysaccharide (LPS). Toll-like receptor-4 (TLR4) recognizes LPS and activates signaling pathways depending on MyD88 or TRIF adaptors. We previously showed that MyD88 is dispensable in ALD. TLR4 induces Type I interferons (IFNs) in an MyD88-independent manner that involves interferon regulatory factor-3 (IRF3). We fed alcohol or control diets to wild-type (WT) and IRF3 knock-out (KO) mice, and to mice with selective IRF3 deficiency in liver parenchymal and bone marrow-derived cells. Whole-body IRF3-KO mice were protected from alcohol-induced liver injury, steatosis, and inflammation. In contrast to WT or bone marrow-specific IRF3-KO mice, deficiency of IRF3 only in parenchymal cells aggravated alcohol-induced liver injury, associated with increased proinflammatory cytokines, lower antiinflammatory cytokine interleukin 10 (IL-10), and lower Type I IFNs compared to WT mice. Coculture of WT primary murine hepatocytes with liver mononuclear cells (LMNC) resulted in higher LPS-induced IL-10 and IFN-ß, and lower tumor necrosis factor alpha (TNF-α) levels compared to LMNC alone. Type I IFN was important because cocultures of hepatocytes with LMNC from Type I IFN receptor KO mice showed attenuated IL-10 levels compared to control cocultures from WT mice. We further identified that Type I IFNs potentiated LPS-induced IL-10 and inhibited inflammatory cytokine production in both murine macrophages and human leukocytes, indicating preserved cross-species effects. These findings suggest that liver parenchymal cells are the dominant source of Type I IFN in a TLR4/IRF3-dependent manner. Further, parenchymal cell-derived Type I IFNs increase antiinflammatory and suppress proinflammatory cytokines production by LMNC in paracrine manner. CONCLUSION: Our results indicate that IRF3 activation in parenchymal cells and resulting type I IFNs have protective effects in ALD by way of modulation of inflammatory functions in macrophages. These results suggest potential therapeutic targets in ALD.

Alcohol exposure as a risk factor for adverse outcomes in elective surgery.

BACKGROUND AND AIMS: Alcohol consumption is a well-documented determinant of adverse perioperative outcome. We sought to determine the effect of active alcohol consumption following elective surgery. METHODS: We queried discharge records from the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP, 2005-2007) for all elective adult admissions. The 7,631 (2.5%) patients with documented alcohol use (active alcohol use of at least two drinks per day within 2 weeks of surgery; ETOH use) underwent elective surgery; 301,994 (97.5%) patients denied ETOH use. Multivariate analysis was performed with adjustments for demographic and comorbid factors. Primary outcome measures included length of stay (LOS), postoperative complications, and death. RESULTS: ETOH use associated with elective surgery decreased over the course of the study (p < 0.0001). ETOH use was an independent predictor of pneumonia (OR 1.98, 95% CI 1.84-2.13), sepsis (OR 1.19, 95% CI 1.03-1.37), superficial surgical site infection (SSI; OR 1.15, 95% CI 1.02-1.31), wound disruption (OR 1.41, 95% CI 1.11-1.80), and prolonged LOS (OR 1.17, 95% CI 1.08-1.26). Except for SSI, these complications were independent risk factors for postoperative mortality. ETOH use was associated with earlier time to wound disruption (9 vs. 11 days; p = 0.04), longer median hospital stays (5 vs. 3 days; p < 0.0001), and longer LOS after operation (4 vs. 3 days; p < 0.0001). CONCLUSIONS: Active alcohol consumption is a significant determinant of adverse outcomes in elective surgery; patients with ETOH use who are scheduled to undergo elective surgery should be appropriately educated and counseled.

Alcohol-induced modulation of signaling pathways in liver parenchymal and nonparenchymal cells: implications for immunity.

Alcoholic liver injury involves a complex array of derangements in cellular signaling of hepatic parenchymal and nonparenchymal cells as well as cells of the immune system. In the hepatocyte, chronic ethanol abuse leads to lipid accumulation and liver steatosis. Multiple pathways are affected to promote lipid accumulation in the ethanol-exposed hepatocyte. Chronic ethanol renders Kupffer cells hyperresponsive to endotoxin, which results in production of inflammatory cytokines and the tumor necrosis factor-alpha via a toll-like receptor 4 dependent pathway, leading to inflammation and hepatic necrosis. Dysfunction of the innate and adaptive immune responses caused by ethanol contributes to impaired antiviral response, inflammatory injury, and autoimmune activation. Recent developments in the literature are reviewed in a model that suggests lipid accumulation, dysregulation of immunity, and impaired antiviral and autoimmune responses as three distinct, though interwoven, pathophysiological mechanisms of alcoholic liver injury.

The alternative reading frame tumor suppressor antagonizes hypoxia-induced cancer cell migration via interaction with the COOH-terminal binding protein corepressor.

The alternative reading frame (ARF) tumor suppressor exerts both p53-dependent and p53-independent activities critical to the prevention of cancer in mice and humans. Recent evidence from mouse models suggests that when p53 is absent, further loss of ARF can widen the tumor spectrum, and potentiate invasion and metastasis. A major target of the p53-independent activity of ARF is the COOH-terminal binding protein (CtBP) family of metabolically regulated transcriptional corepressors, which are degraded upon acute exposure to the ARF protein. CtBPs are activated under conditions of metabolic stress, such as hypoxia, to repress epithelial and proapoptotic genes, and can mediate hypoxia-induced migration of cancer cells. The possibility that ARF could suppress tumor cell migration as part of its p53-independent activities was thus explored. Small-interfering RNA (siRNA)-mediated knockdown of ARF in human lung carcinoma cells led to increased cell migration, especially during hypoxia, and this effect was blocked by concomitant treatment with CtBP2 siRNA. Introduction of ARF into p53 and ARF-null human colon cancer cells inhibited hypoxia-induced migration. Furthermore, overexpression of CtBP2 in ARF-expressing cells enhanced cell migration, and an ARF mutant defective in CtBP-family binding was impaired in its ability to inhibit cell migration induced by CtBP2. ARF depletion or CtBP2 overexpression was associated with decreased PTEN expression and activation of the phosphatidylinositol 3-kinase pathway, and a phosphatidylinositol 3-kinase inhibitor blocked CtBP2-mediated cell migration. Thus, ARF can suppress cell migration by antagonizing CtBP2 and the phosphatidylinositol 3-kinase pathway, and these data may explain the increased aggressiveness of ARF-null tumors in mouse models.

Hepatic tissue engineering for adjunct and temporary liver support: critical technologies.

The severe donor liver shortage, high cost, and complexity of orthotopic liver transplantation have prompted the search for alternative treatment strategies for end-stage liver disease, which would require less donor material, be cheaper, and less invasive. Hepatic tissue engineering encompasses several approaches to develop adjunct internal liver support methods, such as hepatocyte transplantation and implantable hepatocyte-based devices, as well as temporary extracorporeal liver support techniques, such as bioartificial liver assist devices. Many tissue engineered liver support systems have passed the "proof of principle" test in preclinical and clinical studies; however, they have not yet been found sufficiently reliably effective for routine clinical use. In this review we describe, from an engineering perspective, the progress and remaining challenges that must be resolved in order to develop the next generation of implantable and extracorporeal devices for adjunct or temporary liver assist.

Growth factors and nonparenchymal cell conditioned media induce mitogenic responses in stable long-term adult rat hepatocyte cultures.

Most prior studies have characterized hepatocyte proliferative responses in culture systems that do not express a stable differentiated phenotype. We investigated the DNA synthetic response of long-term stable hepatocyte cultures to growth factor stimulation as well as conditioning with nonparenchymal cells (NPCs). Primary rat hepatocytes were cultured on a single layer of collagen (h/C) or Matrigel (h/M), or in a collagen sandwich (C/h/C) or collagen-Matrigel sandwich (M/h/C). Hepatocytes were cultured for 7 days to allow phenotypic stabilization before growth factor addition, except for h/C cultures, which are unstable, where growth factors were added 1 day after seeding. Culture medium was supplemented with a mixture of hepatocyte, epidermal, and vascular endothelial growth factors and interleukin-6, either directly or after conditioning with NPCs for 24 h. Growth factors alone induced hepatocyte DNA synthesis, as measured via [3H]thymidine uptake, in the h/C, C/h/C, and M/h/C configurations. h/M exhibited very low levels of DNA synthesis. In the C/h/C and M/h/C configurations, the greatest stimulation was obtained using NPC-conditioned growth factors. This response was sustained for several days and without decreasing albumin or urea synthesis. These results suggest that hepatocyte mitogens and NPC-derived factors can stimulate DNA synthesis in stable and differentiated hepatocyte cultures.