CfTm

HpTMCI

Ictus(so

Mwgtfmsw

RdaptnpHB

CdpHc

DeEDU

Ifhwp

MtOaEs

Rcobst(cLTsd

TEOCT

CEmab

GEeSMHSA

IadNpaisu

M1tD

S72 Surgical Forum Abstracts J Am Coll Surg

ONCLUSIONS: A macrophage T-cell suppressive factor is secretedollowing TLR stimulation that inhibits adaptive T-cell responses.his factor will need identification and targeting for optimizing tu-or vaccine strategies.

istone deacetylase inhibitors: Friend or foe inreventing neuroblastoma drug resistanceimothy B Lautz MD, Fei Chu MD, PhD, Sandra Clark BS,ary Beth Madonna MDhildren’s Memorial Hospital/Northwestern University, Chicago,

L

NTRODUCTION: Drug resistance poses a major obstacle in thelinical treatment of neuroblastoma. Recent work from our labora-ory has demonstrated that class II histone deacetylases (HDACs) arepregulated in drug resistant neuroblastoma cells. We furtherhowed that HDAC stabilization of hypoxia inducible factor-1 alphaHIF-1a) may contribute to the resistant phenotype. The aim of thistudy is to investigate the effect of HDAC inhibition on the devel-pment of drug resistance.

ETHODS: Two neuroblastoma cell lines (SK-N-SH and Be(2)C)ere incubated with progressively increasing doses of doxorubicin toenerate drug resistance. Parallel groups of cells received pre-reatment with the pan-class II HDAC inhibitor vorinostat (1 �Mor SK-N-SH cells and 0.5 �M for Be(2)C cells) with each logarith-ic increase in doxorubicin concentration. Cell viability and expres-

ion of related target proteins were determined by MTT assay andestern blot, respectively.

ESULTS: Vorinostat is initially synergistic with doxorubicin, pro-ucing 80% more cell death in the wild-type cells than doxorubicinlone. Intermittent vorinostat treatment delays the expression of-glycoprotein and enhances drug sensitivity in SK-N-SH cells. In-erestingly, lower dose vorinostat treatment in the Be(2)C cells didot delay p-glycoprotein expression nor enhance drug sensitivity butromoted the drug resistance phenotype. Rebound overexpression ofDAC6 combined with upregulation of HIF-1a were found in thesee(2)C cells.

ONCLUSIONS: HDAC inhibition with vorinostat can slow theevelopment of drug resistance by preventing emergence of-glycoprotein. Subtherapeutic vorinostat dosing may cause reboundDAC6 overexpression, HIF-1a stabilization and a paradoxical in-

rease in neuroblastoma drug resistance.

eprivation of enteral nutrition and changes inpithelial barrier function in humansiichi A Miyasaka MD, Manabu Okawada MD,aniel H Teitelbaum MDniversity of Michigan, Ann Arbor, MI

NTRODUCTION: Rodent data shows a loss of epithelial barrierunction (EBF) with total parenteral nutrition (TPN), however, littleuman data exists regarding EBF changes after varying time periodsithout enteral nutrition (NPO). We hypothesized that longer NPO

eriods lead to greater EBF decline. b

ETHODS: Human small bowel was obtained during intestinal resec-ion procedures. EBF was measured by transepithelial resistance (TER,hms*cm2) using an Ussing chamber, and by junctional protein (JP)

bundance using real-time PCR (normalized to beta-actin); including:-cadherin, claudin-2, occludin and tight JP-1 (TJP-1) from mucosal

crapings. Data are reported as mean�standard deviation.

ESULTS: Nine patients (age 55 days to 18 years) were studied, andategorized as NPO the night before surgery (Preop) vs. NPO for 5r more days (�5 day). Mean TER was not statistically differentetween groups by unpaired t-test (Table). However, examination ofpecimens taken from non-used ileum or from patients without en-eral exposure for �1 month demonstrated the greatest loss of TER251�39). Analysis of junctional proteins failed to demonstrate aorrelation between their abundance and duration of NPO (Table).inear regression analysis showed correlation between TER andJP-1 (p�0.04), TER and E-cadherin (p�0.09). Regression analy-

is did not show correlation between age versus TER or JP abun-ance.

Preop > 5 days

ransepithelial resistance 316�67 309�66-cadherin 0.20�0.05 0.33�0.07ccludin 0.005�0.002 0.011�0.002laudin-2 0.014�0.005 0.028�0.009ight JP-1 0.067�0.02 0.081�0.02

ONCLUSIONS: This study shows that despite dramatic loss ofBF in rodents on TPN, EBF loss takes far longer to occur in hu-ans. The fairly tight correlation of TER and JP abundance suggests

ccurate measurement of EBF values. Further work will be needed toetter assess EBF changes due to loss of enteral nutrition in humans.

enetic variability influences susceptibility tonterobacter sakazakii (ES)-induced necrotizingnterocolitis (NEC) in micehannon L Castle MD, Claudia Emami MD, Ashanti Franklin BS,onica Williams BS, Jin Wang MS, Anatoly Grishin PhD,enri R Ford MD, MHA, FACS

aban Research Institute/Childrens Hospital Los Angeles, Losngeles, CA

NTRODUCTION: NEC is an inflammatory intestinal disorder thatffects up to 10% of premature neonates. The genetic factors thatetermine susceptibility to this disease are not well-characterized.EC presumably involves colonization of the gut with opportunistic

athogens. One such pathogen, Enterobacter sakazakii (ES) has beenssociated with hospital outbreaks of NEC. We have shown that ESnduces NEC in rats. The purpose of this study was to determine theusceptibility of two genetically different strains of mice commonlysed in disease models, FVB and C57BL/6, to ES-induced NEC.

ETHODS: FVB and C57BL/6 mice were inoculated with 106 or07 cfu ES or equivalent volume of PBS on day of life 1 and allowedo nurse with their mothers until onset of disease or day of life 4.egree of intestinal inflammation was assessed by a pathologist

linded to the groups using H&E-stained ileal samples.