Pancreaticoduodenectomy for the treatment of pancreatic neoplasms in children: A Pediatric Surgical Oncology Research Collaborative study.

BACKGROUND: To better characterize short-term and long-term outcomes in children with pancreatic tumors treated with pancreaticoduodenectomy (PD). METHODS: Patients 21 years of age or younger who underwent PD at Pediatric Surgical Oncology Collaborative (PSORC) hospitals between 1990 and 2017 were identified. Demographic, clinical information, and outcomes (operative complications, long-term pancreatic function, recurrence, and survival) were collected. RESULTS: Sixty-five patients from 18 institutions with a median age of 13 years (4 months-22 years) and a median (IQR) follow-up of 2.8 (4.3) years were analyzed. Solid pseudopapillary tumor of the pancreas (SPN) was the most common histology. Postoperative complications included pancreatic leak in 14% (n = 9), delayed gastric emptying in 9% (n = 6), marginal ulcer in one patient, and perioperative (30-day) death due to hepatic failure in one patient. Pancreatic insufficiency was observed in 32% (n = 21) of patients, with 23%, 3%, and 6% with exocrine, or endocrine insufficiencies, or both, respectively. Children with SPN and benign neoplasms all survived. Overall, there were 14 (22%) recurrences and 11 deaths (17%). Univariate analysis revealed non-SPN malignant tumor diagnosis, preoperative vascular involvement, intraoperative transfusion requirement, pathologic vascular invasion, positive margins, and need for neoadjuvant chemotherapy as risk factors for recurrence and poor survival. Multivariate analysis only revealed pathologic vascular invasion as a risk factor for recurrence and poor survival. CONCLUSION: This is the largest series of pediatric PD patients. PD is curative for SPN and benign neoplasms. Pancreatic insufficiency is the most common postoperative complication. Outcome is primarily associated with histology.

Variation in resource utilization in liver transplantation at freestanding children's hospitals.

We sought to examine the relationship between liver transplant-related total cost, patient outcome, and hospital resource utilization at freestanding children's hospitals. Using the PHIS database, a retrospective study of 374 patients that underwent liver transplantation at 15 freestanding children's hospitals from July 2010 to December 2012 was performed. One-year graft failure and patient mortality rates from July 2010 to December 2012 for each center were also obtained from the SRTR. There was a 5.1-fold difference in median cost (median $146 444, range $59 487-302 058, P<.001) between all centers. A 2.4-fold difference existed in median LOS (median 15 days, range 9-22 days, P<.001) across centers. Median postoperative ICU stay varied from 0 to 7 days (median 4 days, P<.001). Overall, 30-day readmission rate was 55% (31.3%-100%, P<.001). One-year graft failure varied from 0% to 19.1%, with an overall rate of 5.5% (P=.279). One-year patient mortality for all centers was 2.3% (range 0%-11.1%, P=.016). Higher total cost did not correlate with lower readmission rates, patient mortality, graft failure, or any other variable. These data suggest that identifying practice patterns at low-cost centers and implementing them at higher-cost centers may decrease the cost of pediatric liver transplantation without compromising outcomes.

Dynamic alterations in Hippo signaling pathway and YAP activation during liver regeneration.

The Hippo signaling pathway has been implicated in mammalian organ size regulation and tumor suppression. Specifically, the Hippo pathway plays a critical role regulating the activity of transcriptional coactivator Yes-associated protein (YAP), which modulates a proliferative transcriptional program. Recent investigations have demonstrated that while this pathway is activated in quiescent livers, its inhibition leads to liver overgrowth and tumorigenesis. However, the role of the Hippo pathway during the natural process of liver regeneration remains unknown. Here we investigated alterations in the Hippo signaling pathway and YAP activation during liver regeneration using a 70% partial hepatectomy (PH) rat model. Our results indicate an increase in YAP activation by 1 day following PH as demonstrated by increased YAP nuclear localization and increased YAP target gene expression. Investigation of the Hippo pathway revealed a decrease in the activation of core kinases Mst1/2 by 1 day as well as Lats1/2 and its adapter protein Mob1 by 3 days following PH. Evaluation of liver-to-body weight ratios indicated that the liver reaches its near normal size by 7 days following PH, which correlated with a return to baseline YAP nuclear levels and target gene expression. Additionally, when liver size was restored, Mst1/2 kinase activation returned to levels observed in quiescent livers indicating reactivation of the Hippo signaling pathway. These findings illustrate the dynamic changes in the Hippo signaling pathway and YAP activation during liver regeneration, which stabilize when the liver-to-body weight ratio reaches homeostatic levels.

Exercise training enhanced myocardial endothelial nitric oxide synthase (eNOS) function in diabetic Goto-Kakizaki (GK) rats.

BACKGROUND: Different mechanisms of diabetic-induced NO dysfunction have been proposed and central to most of them are significant changes in eNOS function as the rate-limiting step in NO bioavailability. eNOS exists in both monomeric and dimeric conformations, with the dimeric form catalyzing the synthesis of nitric oxide, while the monomeric form catalyzes the synthesis of superoxide (O2-). Diabetic-induced shifts to decrease the dimer:monomer ratio is thought to contribute to the degradation of nitric oxide (NO) bioavailability. Exercise has long been useful in the management of diabetes. Although exercise-induced increases expression of eNOS has been reported, it is unclear if exercise may alter the functional coupling of eNOS. METHODS: To investigate this question, Goto-Kakizaki rats (a model of type II diabetes) were randomly assigned to a 9-week running program (train) or sedentary (sed) groups. RESULTS: Exercise training significantly (p < .05) increased plantaris muscle cytochrome oxidase, significantly improved glycosylated hemoglobin (sed: 7.33 +/- 0.56%; train: 6.1 +/- 0.18%), ad improved insulin sensitivity. Exercise increased both total eNOS expression and the dimer:monomer ratio in the left ventricle LV (sed: 11.7 +/- 3.2%; train: 41.4 +/- 4.7%). Functional analysis of eNOS indicated that exercise induced significant increases in nitric oxide (+28%) production and concomitant decreases in eNOS-dependent superoxide (-12%) production. This effect was observed in the absence of tetrahydrobiopterin (BH4), but not in the presence of exogenous BH4. Exercise training also significantly decreased NADPH-dependent O2- activity. CONCLUSION: Exercise-induced increased eNOS dimerization resulted in an increased coupling of the enzyme to facilitate production of NO at the expense of ROS generation. This shift that could serve to decrease diabetic-related oxidative stress, which should serve to lessen diabetic-related complications.

YAP Subcellular Localization and Hippo Pathway Transcriptome Analysis in Pediatric Hepatocellular Carcinoma.

Pediatric hepatocellular carcinoma (HCC) is a rare tumor which is associated with an extremely high mortality rate due to lack of effective chemotherapy. Recently, the Hippo pathway and its transcriptional co-activator Yes-associated protein (YAP) have been shown to play a role in hepatocyte proliferation and development of HCC in animal models. Therefore, we sought to examine the activity of YAP and the expression of Hippo pathway components in tumor and non-neoplastic liver tissue from 7 pediatric patients with moderately differentiated HCC. None of the patients had underlying cirrhosis or viral hepatitis, which is commonly seen in adults with HCC. This highlights a major difference in the pathogenesis of HCC between children and adults. We found a statistically significant increase in YAP nuclear localization in 100% of tumors. YAP target gene (CCNE1, CTGF, Cyr61) mRNA expression was also increased in the tumors that had the most significant increase in YAP nuclear localization. Based on Ki67 co-localization studies YAP nuclear localization was not simply a marker of proliferation. Our results demonstrate a clear increase in YAP activity in moderately differentiated pediatric HCC, providing evidence that it may play an important role in tumor survival and propagation.

The effect of graft type on mortality in liver transplantation for hepatocellular carcinoma.

BACKGROUND: Liver transplantation (LT) with living-donor (LD-P) and deceased-donor (DD-P) partial grafts for hepatocellular carcinoma (HCC) may be associated with worse outcomes. Using the United Network for Organ Sharing (UNOS), we aimed to: (1) examine the risk of mortality in LT for HCC, (2) to establish if this risk is affected by partial graft use, and (3) to determine if this effect is mitigated by improved tumor-associated risk stratification. MATERIAL AND METHODS: All first-time adult LT recipients were analyzed (3/2002-12/2012), including 2,353 LD-P, 727 DD-P, and 47,833 DD whole (DD-W) grafts. Cox proportional hazards models were used to examine the risk of mortality given HCC. Interaction/subset analyses were used to examine the effect of tumor-risk and graft-type on outcome. Presence of an HCC exception and low alpha-fetoprotein (AFP) level (<66 ng/mL) were considered favorable. RESULTS: Overall, HCC was associated with an increased mortality risk compared to the absence of HCC (HR 1.21 [1.15-1.27]), and the use of partial grafts was noted to further intensify this risk. However, HCC with a favorable risk profile had more comparable outcomes to patients without HCC and this finding was similar across all graft-types (Given LD-P: HR 1.14 [0.76-1.73]; Given DD-P: HR1.05 [0.71-1.56]; Given DD-W: HR1.08 [1.02-1.14]). On subset analysis, all graft types had similar outcomes given either favorable-risk HCC or the absence of HCC. CONCLUSIONS: There is no significant difference in outcomes between whole and partial grafts given (1) patients with HCC with a favorable risk-profile or (2) patients without HCC.

Neonatal liver physiology.

In the neonate, the liver is relatively immature and undergoes several changes in its functional capacity during the early postnatal period. The essential liver functions can be classified into three categories: metabolism, detoxification, and bile synthesis. In general, the immature liver function has limited consequences on the healthy term neonate. However, preterm neonates are particularly susceptible to the effects of the immature liver function placing them at risk of hypoglycemia, hyperbilirubinemia, cholestasis, bleeding, and impaired drug metabolism. An appreciation of the dynamic changes in liver function during the neonatal period is essential for successful management of neonates who require medical and surgical interventions. This review will focus on the neonatal liver function as well as the changes that the liver undergoes as it matures.