Joseph DiNorcia

TLR4 Signaling via NANOG Cooperates With STAT3 to Activate Twist1 and Promote Formation of Tumor-initiating Stem-like Cells in Livers of Mice.

BACKGROUND & AIMS Obesity and alcohol consumption contribute to steatohepatitis, which increases the risk for hepatitis C virus (HCV)-associated hepatocellular carcinomas (HCCs). Mouse hepatocytes that express HCV-NS5A in liver up-regulate the expression of Toll-like receptor 4 (TLR4), and develop liver tumors containing tumor-initiating stem-like cells (TICs) that express NANOG. We investigated whether the TLR4 signals to NANOG to promote the development of TICs and tumorigenesis in mice placed on a Western diet high in cholesterol and saturated fat (HCFD). METHODS We expressed HCV-NS5A from a transgene (NS5A Tg) in Tlr4-/- (C57Bl6/10ScN), and wild-type control mice. Mice were fed a HCFD for 12 months. TICs were identified and isolated based on being CD133+, CD49f+, and CD45-. We obtained 142 paraffin-embedded sections of different stage HCCs and adjacent nontumor areas from the same patients, and performed gene expression, immunofluorescence, and immunohistochemical analyses. RESULTS A higher proportion of NS5A Tg mice developed liver tumors (39%) than mice that did not express HCV NS5A after the HCFD (6%); only 9% of Tlr4-/- NS5A Tg mice fed HCFD developed liver tumors. Livers from NS5A Tg mice fed the HCFD had increased levels of TLR4, NANOG, phosphorylated signal transducer and activator of transcription (pSTAT3), and TWIST1 proteins, and increases in Tlr4, Nanog, Stat3, and Twist1 messenger RNAs. In TICs from NS5A Tg mice, NANOG and pSTAT3 directly interact to activate expression of Twist1. Levels of TLR4, NANOG, pSTAT3, and TWIST were increased in HCC compared with nontumor tissues from patients. CONCLUSIONS HCFD and HCV-NS5A together stimulated TLR4-NANOG and the leptin receptor (OB-R)-pSTAT3 signaling pathways, resulting in liver tumorigenesis through an exaggerated mesenchymal phenotype with prominent Twist1-expressing TICs.

Damage control as a strategy to manage postreperfusion hemodynamic instability and coagulopathy in liver transplant

IMPORTANCE Damage control (DC) with intra-abdominal packing and delayed reconstruction is an accepted strategy in trauma and acute care surgery but has not been evaluated in liver transplant. OBJECTIVE To evaluate the incidence, effect on survival, and predictors of the need for DC using intra-abdominal packing and delayed biliary reconstruction in patients with coagulopathy or hemodynamic instability after liver allograft reperfusion. DESIGN, SETTING, AND PARTICIPANTS We performed a retrospective analysis of adults undergoing liver transplant at a large transplant center from February 1, 2002, through July 31, 2012. MAIN OUTCOMES AND MEASURES Predictors of DC, effects on graft, and patient survival. RESULTS Of 1813 patients, 150 (8.3%) underwent DC during liver transplant, with 84 (56.0%) requiring a single additional operation for biliary reconstruction and abdominal closure and 57 (38.0%) requiring multiple additional operations. Compared with recipients without DC, patients requiring DC had greater Model for End-stage Liver Disease scores (33 vs 27; P < .001); more frequent pretransplant hospitalization (72.0% vs 47.9%; P < .001), intubation (33.3% vs 19.9%; P < .001), vasopressors (23.2% vs 10.9%; P < .001), renal replacement therapy (49.6% vs 30.3%; P < .001), and prior major abdominal operations (48.3% vs 21.9%; P < .001), including prior liver transplant (29.3% vs 8.9%; P < .001); greater operative transfusion requirements (37 vs 13 units of packed red blood cells; P < .001); worse intraoperative base deficit (10.3 vs 8.4; P = .03); more frequent postreperfusion syndrome (56.2% vs 27.3%; P < .001); and longer cold (430 vs 404 minutes; P = .04) and warm (46 vs 41 minutes; P < .001) ischemia times. Patients who underwent DC followed by a single additional operation for biliary reconstruction and abdominal closure had similar 1-, 3-, and 5-year graft survival (71%, 62%, and 62% vs 81%, 71%, and 67%; P = .26) and patient survival (72%, 64%, and 64% vs 84%, 75%, and 70%; P = .15) compared with recipients not requiring DC. Multivariate predictors of DC included prior liver transplant or major abdominal operation, longer pretransplant recipient and donor length of stay, greater Model for End-stage Liver Disease score, and longer warm and cold ischemia times (C statistic, 0.75). CONCLUSIONS AND RELEVANCE To our knowledge, this study represents the first large report of DC as a viable strategy for liver transplant recipients with coagulopathy or hemodynamic instability after allograft reperfusion. In DC recipients not requiring additional operations, outcomes are excellent and comparable to 1-stage liver transplant.

Predictive Factors of Neurological Complications and One-Month Mortality after Liver Transplantation

Background: Neurological complications are common after orthotopic liver transplantation (OLT). We aimed to characterize the risk factors associated with neurological complications and mortality among patients who underwent OLT in the post-model for end-stage liver disease (MELD) era. Methods: In a retrospective review, we evaluated 227 consecutive patients at the Keck Hospital of the University of Southern California before and after OLT to define the type and frequency of and risk factors for neurological complications and mortality. Results: Neurological complications were common (n = 98), with encephalopathy being most frequent (56.8%), followed by tremor (26.5%), hallucinations (11.2%), and seizure (8.2%). Factors associated with neurological complications after OLT included preoperative dialysis, hepatorenal syndrome, renal insufficiency, intra-operative dialysis, preoperative encephalopathy, preoperative mechanical ventilation, and infection. Preoperative infection was an independent predictor of neurological complications (OR 2.83, 1.47–5.44). One-month mortality was 8.8% and was independently associated with urgent re-transplant, preoperative intubation, and intra-operative arrhythmia. Conclusion: Neurological complications are common in patients undergoing OLT in the post-MELD era, with encephalopathy being most frequent. An improved understanding of the risk factors related to both neurological complications and one-month mortality post-transplantation can better guide perioperative care and help improve outcomes among OLT patients.

Inequity in organ allocation for patients awaiting liver transplantation: Rationale for uncapping the model for end-stage liver disease

BACKGROUND & AIM The goal of organ allocation is to distribute a scarce resource equitably to the sickest patients. In the United States, the Model for End-stage Liver Disease (MELD) is used to allocate livers for transplantation. Patients with greater MELD scores are at greater risk of death on the waitlist and are prioritized for liver transplant (LT). The MELD is capped at 40 however, and patients with calculated MELD scores >40 are not prioritized despite increased mortality. We aimed to evaluate waitlist and post-transplant survival stratified by MELD to determine outcomes in patients with MELD >40. METHODS Using United Network for Organ Sharing data, we identified patients listed for LT from February 2002 through to December 2012. Waitlist candidates with MELD ⩾40 were followed for 30days or until the earliest occurrence of death or transplant. RESULTS Of 65,776 waitlisted patients, 3.3% had MELD ⩾40 at registration, and an additional 7.3% had MELD scores increase to ⩾40 after waitlist registration. A total of 30,369 (46.2%) underwent LT, of which 2,615 (8.6%) had MELD ⩾40 at transplant. Compared to MELD 40, the hazard ratio of death within 30days of registration was 1.4 (95% CI 1.2-1.6) for patients with MELD 41-44, 2.6 (95% CI 2.1-3.1) for MELD 45-49, and 5.0 (95% CI 4.1-6.1) for MELD ⩾50. There was no difference in 1- and 3-year survival for patients transplanted with MELD >40 compared to MELD=40. A survival benefit associated with LT was seen as MELD increased above 40. CONCLUSIONS Patients with MELD >40 have significantly greater waitlist mortality but comparable post-transplant outcomes to patients with MELD=40 and, therefore, should be given priority for LT. Uncapping the MELD will allow more equitable organ distribution aligned with the principle of prioritizing patients most in need. Lay summary: In the United States (US), organs for liver transplantation are allocated by an objective scoring system called the Model for End-stage Liver Disease (MELD), which aims to prioritize the sickest patients for transplant. The greater the MELD score, the greater the mortality without liver transplant. The MELD score, however, is artificially capped at 40 and thus actually disadvantages the sickest patients with end-stage liver disease. Analysis of the data advocates uncapping the MELD score to appropriately prioritize the patients most in need of a liver transplant.

Antibody-mediated rejection: what is the clinical relevance?

Purpose of review The review outlines the diagnosis, clinical implications, and treatment strategies for acute and chronic antibody-mediated rejection (AMR) after orthotopic liver transplantation (OLT). Recent findings A combination of clinical work-up, histopathology, C4d staining, and donor-specific antibody (DSA) should be used to diagnose AMR. The differential diagnosis for idiopathic fibrosis now includes chronic AMR. Characterization of pathogenic DSA continues to progress. De-novo and persistent DSA, particularly of the IgG3 subtype, are associated with inferior long-term outcomes. The liver allograft may confer long-term immunologic benefits to the kidney allograft after simultaneous liver-kidney transplant. The more widespread use of rituximab has improved outcomes in ABO-incompatible OLT. Although larger long-term studies of treatment options are needed, compliance with tacrolimus-based immunosuppression and transfusion minimization are agreed upon preventive strategies. Summary AMR has evolved into an established pathology in OLT recipients. Acute AMR may lead to early graft loss whereas chronic AMR results in progressive fibrosis if unrecognized. DSAs, likely in the setting of predisposing environmental factors, appear to play a role in T cell–mediated rejection and long-term graft outcomes.

Balanced blood product transfusion during liver transplantation

This study was conducted to determine whether an intra‐operative ratio of at least 1:1:2 of fresh frozen plasma (FFP):platelets (PLTs):packed red blood cells (pRBCs) improves outcomes in orthotopic liver transplantation (OLT).

Perioperative Renal Replacement Therapy in Liver Transplantation

Renal dysfunction is a common perioperative complication in patients with end-stage liver disease (ESLD) undergoing liver transplantation (LT), with an estimated prevalence of 30% in pretransplant patients and up to 60% after transplant. Since the implementation of the model for endstage liver disease (MELD) for liver allocation in the United States in 2002, a greater number of patients with renal dysfunction are undergoing LT. Serum creatinine (SCr) weighs heavily in the MELD score calculation, and, consequently, patients with renal dysfunction receive priority for LT. Whether occurring before or after transplant, renal dysfunction is a significant risk factor for major morbidity and mortality. Renal replacement therapy (RRT) thus has become essential in the perioperative care of the liver transplant patient. In this chapter, we review the causes of renal dysfunction and the use of RRT before, during, and after LT.

794 Prophylactic Pancreatic Resection in Patients With IPMN Does Not Negatively Impact Patient Quality of Life: A Preliminary Study

Introduction: The use of proximal esophageal pH monitoring to diagnose laryngopharyngeal reflux (LPR) is disappointing. We hypothesized that failure to maintain adequate alkalization instead of acidification of the cervical esophagus may be a better indicator of proximal esophageal exposure to gastric juice. As currently performed, acidification of the proximal esophagus is defined by exposure to a pH 7 and to use the inability to maintain this as an indication of LPR. Material and methods: The normal subject group consisted of 59 asymptomatic volunteers who had a complete foregut evaluation including pH monitoring of the proximal esophagus. After analysis of proximal esophageal exposure to a pH 7. Results: The median percent time the pH was >7 was significantly less in LPR patients prior to surgery compared to normal subjects [10.4 (2.8-21.9) vs. 38.2(27-56), p 7 in normal subjects was 19.6%. In 84% of the LPR patients (43/51) the percent time pH was >7 was less than 19.6, indicating they were unable to maintain a pH>7. In contrast, 69% of the patients (35/51) had an abnormal test when the pH records from proximal esophagus were analyzed using the % time pH 7. Conclusion: Normal subjects are expected to have a pH>7 in cervical esophagus for at least 19.6% of the monitored period. Using the threshold value for pH>7 rather than 7 as the threshold to identify reflux as the cause of LPR symptoms. It identifies two third of the patients whose analysis of their pH records using pH<4 is falsely normal.

1040 127 Resections for Pancreatic Neuroendocrine Tumor: Evaluating the Impact of Minimally Invasive and Parenchymal-Sparing Surgical Techniques

Background: Gastro-gastric fistulae are a challenging complication of obesity surgery that often requires surgical revision. Performance of endoscopic fistula closure is increasing and may provide a less invasive alternative; nevertheless, the majority of fistulae ultimately require surgical revision. The impact of prior endoscopic intervention on surgical revision outcomes remains unknown. We present the largest series on surgical revision of gastro-gastric fistulae to date and perform cohort analysis to assess the impact of prior endoscopic therapy. Methods: A database of all bariatric surgical revisions performed at a single institution was searched for patients with gastro-gastric fistula. Electronic records and clinic charts were then reviewed. The cohort was divided between patients with attempted endoscopic fistula closure prior to surgical revision, and patients without endoscopic therapy prior to revision. 30-day morbidity and mortality was the primary outcome. Age, sex, initial surgery BMI, revision surgery BMI, type of initial surgery, type of revision surgery, number of prior surgeries, number of endoscopic fistula closure attempts, presence of dilated gastrojejunostomy, number of endoscopic clips placed, number of endoscopic sutures placed, fistula size, smoking status, thyroid disease, presence of diabetes, medical co-morbidities, OR time and 30-day minor and major post-operative complications were collected. Categorical and continuous data were analyzed with Fishers exact test and Wilcoxon signed-rank test respectively. Results: 68 total cases of surgical revision were reviewed. 35 cases were performed for gastro-gastric fistula. Of 35 cases, 22 had attempted endoscopic closure prior to surgical revision while 13 went directly to surgical revision. In the endoscopy group, 2 minor complications and 7 major complications occurred (total 9/22; 40.9%). In the surgery only group, 3 minor complications and 3 major complications occurred (total 6/13; 46.1%). No deaths occurred. No statistical difference existed in the demographic or primary outcome variables of interest between the two groups. Sub-group analysis of the endoscopy group did suggest a relationship between the number of sutures (p=0.04) and clips p=(0.04) placed at the gastrojejunostomy and major 30-day complications. Conclusion: In the largest study of surgical revision of gastro-gastric fistulae to date, there is no evidence that prior attempts at endoscopic fistula closure lead to increased complications at the time of surgical revision.