Faculty Bibliography

Although the polycomb group protein Enhancer of Zeste Homolog 2 (EZH2) is well recognized for its role as a key regulator of cell differentiation, its involvement in tissue regeneration is largely unknown. Here we show that EZH2 is up-regulated following cerulein-induced pancreatic injury and is required for tissue repair by promoting the regenerative proliferation of progenitor cells. Loss of EZH2 results in impaired pancreatic regeneration and accelerates KRas(G12D)-driven neoplasia. Our findings implicate EZH2 in constraining neoplastic progression through homeostatic mechanisms that control pancreatic regeneration and provide insights into the documented link between chronic pancreatic injury and an increased risk for pancreatic cancer.

BACKGROUND: Excess use of intravenous fluid can increase post-operative complications. We examined the influence of intra-operative crystalloid (IOC) administration on complications following pancreaticodudenectomy (PD) for pancreatic adenocarcinoma. METHODS: We categorized 188 patients who underwent PD for adenocarcinoma (1990-2009) into two groups: Group I received <6,000 ml and Group II received >/=6,000 ml IOC. Differences between groups in length of stay, overall morbidity, and 30-day mortality were evaluated. RESULTS: There were 86 patients in Group I and 102 in Group II. Group I patients were older and with higher percentage of women, but similar in regards to performance status, ASA score, underlying comorbidities, and administration of neo-adjuvant treatment. Group II patients had longer operations, increased blood loss, and higher rates of intra-operative blood transfusions. There were two post-operative deaths, both in the Group II (P = 0.5). Post-operative overall morbidity was 45.7%, without differences between the two groups (44.2% vs. 47.1%, P = 0.7). Likewise, length of post-operative stay was similar in both groups (13.8 days vs. 14.5 days, P = 0.5). CONCLUSIONS: The volume of IOC increased with duration of surgery, intra-operative blood losses, and intra-operative blood transfusion, but did not correlate with post-operative morbidity. J. Surg. Oncol (c) 2011 Wiley-Liss, Inc

BACKGROUND: Simulation-based training provides a low-stress learning environment where real-life emergencies can be practiced. Simulation can improve surgical education and patient care in crisis situations through a team approach emphasizing interpersonal and communication skills. OBJECTIVE: This study assessed the effects of simulation-based training in the context of trauma resuscitation in teams of trainees. METHODS: In a New York State-certified level I trauma center, trauma alerts were assessed by a standardized video review process. Simulation training was provided in various trauma situations followed by a debriefing period. The outcomes measured included the number of healthcare workers involved in the resuscitation, the percentage of healthcare workers in role position, time to intubation, time to intubation from paralysis, time to obtain first imaging study, time to leave trauma bay for computed tomography scan or the operating room, presence of team leader, and presence of spinal stabilization. Thirty cases were video analyzed presimulation and postsimulation training. The two data sets were compared via a 1-sided t test for significance (p < 0.05). Nominal data were analyzed using the Fischer exact test. RESULTS: The data were compared presimulation and postsimulation. The number of healthcare workers involved in the resuscitation decreased from 8.5 to 5.7 postsimulation (p < 0.001). The percentage of people in role positions increased from 57.8% to 83.6% (p = 0.46). The time to intubation from paralysis decreased from 3.9 to 2.8 minutes (p < 0.05). The presence of a definitive team leader increased from 64% to 90% (p < 0.05). The rate of spine stabilization increased from 82% to 100% (p < 0.08). After simulation, training adherence to the advanced trauma life support algorithm improved from 56% to 83%. CONCLUSIONS: High-stress situations simulated in a low-stress environment can improve team interaction and educational competencies. Providing simulation training as a tool for surgical education may enhance patient care

Introduction: Chronic pancreatitis (CP) is characterized by fibro-inflammatory transformation of the pancreatic parenchyma. the precise cellular mediators in CP are incompletely understood. Dendritic cells (DC) have recently emerged as initiators of organ-specific inflammation. Pancreatic stellate cells (PSC) become potently pro-inflammatory in CP and are primarily responsible for deposition of extracellular matrix proteins and fibrillar collagen. We postulated that an intimate relationship between DC and PSC mediate the dramatic fibro-inflammatory changes in CP. Methods: DC were isolated from bone marrow aspirates and cultured for 8 days in complete RPMI supplemented with murine GMCSF. PSC were isolated aftermechanical and chemical digestion of pancreas, followed by density centrifugation and plastic adherence. DC-PSC co-culture was accomplished by culturing equal number of DC and PSC for 24 to 48 hours before washing off the non-adherent DC. Cell culture supernatant was assayed using cytometric bead or ELISA. for in vivo experiments, a three week caerulein model of chronic pancreatitis was employed in C57BL/6micewith selectmice receiving i. p. adoptive transfer of DC (1x106 thrice weekly). in vivo PSC activation was measured using monoclonal antibodies directed against Desmin and a-SMA. Results: in vitroDC-PSCco-culture resulted in activation ofPSCsurface phenotype and the production ofhigher levels ofPDGF,as well as numerous chemokines and cytokines byPSC(Table). Effectswere contingent on direct cellular interaction betweenDCand PSC as well as DCexpression of ICAM-1 and MyD88. in vivo i. p. adoptive transfer of DC in murine caerulein-induced chronic pancreatitis resulted in markedly increased fibro- inflammatory changes in the pancreas as well as 4-fold increase in percent desmin-positive acini, and approximately 80% a-SMA-positive acini (Figure). However, whereasDCinduced PSC to become pro-inflammatory, DC inhibited PSC proliferation, failed to stimulate PSC migration, and did not induce PSC to express higher levels of extra-cellular matrix proteins or Collagen I in co-culture experiments. Furthermore, our experimental data suggest bi-directional cross-talk asPSCprevented DCmaturation but acted as a potentDCchemoattractant. Conclusions: DCand PSC induce robust bidirectional crosstalk that affects CP. DCinduce PSC to become pro-inflammatory, but do cannot cause PSC to adopt fully mature myofibroblast-like properties. (Figure presented)

BACKGROUND & AIMS: The cellular mediators of acute pancreatitis are incompletely understood. Dendritic cells (DCs) can promote or suppress inflammation, depending on their subtype and context. We investigated the roles of DC in development of acute pancreatitis. METHODS: Acute pancreatitis was induced in CD11c.DTR mice using caerulein or L-arginine; DCs were depleted by administration of diphtheria toxin. Survival was analyzed using Kaplan-Meier method. RESULTS: Numbers of major histocompatibility complex II(+)CD11c(+) DCs increased 100-fold in pancreata of mice with acute pancreatitis to account for nearly 15% of intrapancreatic leukocytes. Intrapancreatic DCs acquired a distinct immune phenotype in mice with acute pancreatitis; they expressed higher levels of major histocompatibility complex II and CD86 and increased production of interleukin-6, membrane cofactor protein-1, and tumor necrosis factor-alpha. However, rather than inducing an organ-destructive inflammatory process, DCs were required for pancreatic viability; the exocrine pancreas died in mice that were depleted of DCs and challenged with caerulein or L-arginine. All mice with pancreatitis that were depleted of DCs died from acinar cell death within 4 days. Depletion of DCs from mice with pancreatitis resulted in neutrophil infiltration and increased levels of systemic markers of inflammation. However, the organ necrosis associated with depletion of DCs did not require infiltrating neutrophils, activation of nuclear factor-kappaB, or signaling by mitogen-activated protein kinase or tumor necrosis factor-alpha. CONCLUSIONS: DCs are required for pancreatic viability in mice with acute pancreatitis and might protect organs against cell stress

Acetaminophen (APAP) overdose is one of the most frequent causes of acute liver failure in the United States and is primarily mediated by toxic metabolites that accumulate in the liver upon depletion of glutathione stores. However, cells of the innate immune system, including natural killer (NK) cells, neutrophils, and Kupffer cells, have also been implicated in the centrilobular liver necrosis associated with APAP. We have recently shown that dendritic cells (DCs) regulate intrahepatic inflammation in chronic liver disease and, therefore, postulated that DC may also modulate the hepatotoxic effects of APAP. We found that DC immune-phenotype was markedly altered after APAP challenge. In particular, liver DC expressed higher MHC II, costimulatory molecules, and Toll-like receptors, and produced higher interleukin (IL)-6, macrophage chemoattractant protein-1 (MCP-1), and tumor necrosis factor alpha (TNF-alpha). Conversely, spleen DC were unaltered. However, APAP-induced centrilobular necrosis, and its associated mortality, was markedly exacerbated upon DC depletion. Conversely, endogenous DC expansion using FMS-like tyrosine kinase 3 ligand (Flt3L) protected mice from APAP injury. Our mechanistic studies showed that APAP liver DC had the particular capacity to prevent NK cell activation and induced neutrophil apoptosis. Nevertheless, the exacerbated hepatic injury in DC-depleted mice challenged with APAP was independent of NK cells and neutrophils or numerous immune modulatory cytokines and chemokines. Conclusion: Taken together, these data indicate that liver DC protect against APAP toxicity, whereas their depletion is associated with exacerbated hepatotoxicity. (HEPATOLOGY 2011;)

INTRODUCTION: Tolerance is the hallmark of hepatic immune function and dendritic cells (DC) are critical to this phenomenon. Lipid accumulation causes DC dysfunction in cancer.We postulated that liver DC are conspicuously lipid-rich and therefore mediate tolerance. METHODS: Immune cells from C57BL/6 livers were isolated using FACS. Cytokines were measured using a bead array. CTL lysis was measured using Cr51. NK and iNKT cells were tested in DC cocultures. EG7 was employed in tumor experiments. RESULTS: We discovered two distinct liver DC populations, high lipid containing (HL-DC) and low lipid containing (LL-DC). HL-DC exhibited an activated phenotype, produced robust levels of cytokines, activated CD4+ T, NK and iNKT cells, induced CTL responses and prevented tumor growth after adoptive transfer immunization. Conversely, LL-DC induced Tregs, anergy to cancer, and mediated tolerance to oral antigen. (Table Presented) CONCLUSIONS: Endogenous lipid content in hepatic DC subsets defines their immunogenic potential. Contrary to our hypothesis, HL-DC are potently immunogenic while LL-DC maintain tolerance. Manipulation of the HL-Dc: LL-DC ratio may be an attractive strategy for experimental therapeutics to modulate hepatic immunity and tolerance

Minority melanoma patients have worse survival. In this study, we evaluated the impact of socioeconomic and demographic factors on minority melanoma patients presenting to two different New York City hospitals (one public and one private) managed by the same multidisciplinary team. Sociodemographic and clinicopathologic characteristics were retrieved for melanoma patients presenting to Bellevue Hospital Center (BHC), a public hospital, and the New York University Cancer Institute (NYUCI), a private cancer center. Socioeconomic data was obtained from the United States Census Bureau database. The Kruskal-Wallis and chi-square tests were used to evaluate the associations between race/ethnicity and continuous and categorical variables (e.g. income, stage at presentation), respectively. Minorities comprised 2% (27/1296) of melanoma patients at the NYUCI compared to 42% (50/119) at BHC. Those presenting to the NYUCI were more likely to have a higher median household income (P = 0.05), a higher educational level (P = 0.04), and an earlier stage at presentation (P = 0.02) than those at BHC. NYUCI patients were predominantly covered by commercial insurance (70%), whereas Medicaid (62%) was common among BHC patients. Only 19% of Hispanic patients at BHC chose English as their preferred language. Our data demonstrate that language and health care system factors affect melanoma presentation in minorities

The normal liver is characterized by immunologic tolerance. Primary mediators of hepatic immune tolerance are liver sinusoidal endothelial cells (LSECs). LSECs block adaptive immunogenic responses to Ag and induce the generation of T regulatory cells. Hepatic fibrosis is characterized by both intense intrahepatic inflammation and altered hepatic immunity. We postulated that, in liver fibrosis, a reversal of LSEC function from tolerogenic to proinflammatory and immunogenic may contribute to both the heightened inflammatory milieu and altered intrahepatic immunity. We found that, after fibrotic liver injury from hepatotoxins, LSECs become highly proinflammatory and secrete an array of cytokines and chemokines. In addition, LSECs gain enhanced capacity to capture Ag and induce T cell proliferation. Similarly, unlike LSECs in normal livers, in fibrosis, LSECs do not veto dendritic cell priming of T cells. Furthermore, whereas in normal livers, LSECs are active in the generation of T regulatory cells, in hepatic fibrosis LSECs induce an immunogenic T cell phenotype capable of enhancing endogenous CTLs and generating potent de novo CTL responses. Moreover, depletion of LSECs from fibrotic liver cultures mitigates the proinflammatory milieu characteristic of hepatic fibrosis. Our findings offer a critical understanding of the role of LSECs in modulating intrahepatic immunity and inflammation in fibro-inflammatory liver disease