Proteasome inhibitor PS-341 inhibits NFkB and ameliorates ischemia-reperfusion injury in orthotopic liver transplant (OLT) with a steatotic graft

S90

Transplantation

J Am Coll Surg

I/R⫹saline 3hrs

I/R⫹NN 3hrs

I/R⫹saline 6hrs

I/R⫹NN 6hrs

ALT (IU/L)

2,782 ⫾ 533

1,616 ⫾ 274.7ⴱ

3,579 ⫾ 203

1,449 ⫾ 302ⴱ

IL-6 mRNA (fold increase) TNF-␣ mRNA iNOS mRNA

8.5 ⫾ 2.4

5.1 ⫾ 1.6ⴱ

23.7 ⫾ 10

3.8 ⫾ 1.9ⴱ

2.09 ⫾ 0.56

1.63 ⫾ 0.38ⴱ

7.86 ⫾ 3.5

1.76 ⫾ 0.22ⴱ

11.65 ⫾ 2.8

5.8 ⫾ 1.1ⴱ

15 ⫾ 8.7

4.3 ⫾ 2ⴱ

CONCLUSIONS: PS-341 effectively inhibits early NFkB activation after OLT in a steatotic graft model, and significantly reduces hepatic tissue levels of proinflammtory cytokines: TNF-a, IL-1b and MIP-2. PS-341 treatment also resulted in systemic and distant organ effects, significantly reducing serum and lung protein MIP-2 levels. This may represent a novel therapeutic strategy in ameliorating early ischemia-reperfusion injury following OLT in marginal grafts due to steatosis.

(ⴱ indicates p⬍0.05 w/ n⫽6-9)

CONCLUSIONS: Enhancement of arginine availability through arginase blockade with NN is a novel strategy to prevent liver I/R injury.This protection may be mediated through the arginine-NO pathway.

Kazunori Inuzuka MD, Naoki Unno MD, FACS, Naoto Yamamoto MD, Daisuke Sagara MD, Minoru Suzuki MD, Hiroyuki Konno MD Hamamatsu University School of Medicine, Hamamatsu, Japan

Proteasome inhibitor PS-341 inhibits NFkB and ameliorates ischemia-reperfusion injury in orthotopic liver transplant (OLT) with a steatotic graft

INTRODUCTION: Perfluorochemicals (PFC) are chemical substances which have a higher solubility for oxygen under hyperbaric oxygen (HBO) pressure. The aim of this study is to investigate the effect of cold HBO-PFC/UW solution on preservation of rat’s small intestinal graft.

Jane M Liaw MD, Jianluo Jia MD, Sean C Glasgow MD, Wei Liu MD, Krista A Csontos BS, Sabarinathan Ramachandran PhD, Thalachallour Mohanakumar PhD, William C Chapman MD Washington University, St Louis, MO INTRODUCTION: Hepatic steatosis is noted with increasing frequency among potential donors for transplantation. Steatotic grafts are more susceptible to ischemia-reperfusion (I/R) injury, leading to increased primary graft dysfunction and nonfunction, and multiorgan injury. Since more severe I/R injury is associated with increased NFkB activation, we investigated the effects of PS-341, an NFkB inhibitor, in a steatotic OLT model. METHODS: OLTs from obese to lean Zucker rats were performed with and without intravenous PS-341 treatment (0.25mg/kg) immediately prior to graft procurement (n⫽4). Following 2-hour cold ischemia and 2-hour reperfusion, tissue/serum were collected. NFkB activation was measured by digitally-quantified EMSA. Proinflammatory cytokines were measured using ELISA. Data were analyzed by 2-tailed unpaired t-test. RESULTS: PS-341 inhibited hepatic NFkB activation compared to untreated animals. Treatment significantly reduced TNF-a, IL-1 and MIP-2 liver protein levels (table). Treated animals also showed significantly reduced MIP-2 levels in lung protein and serum, but increased serum IL-1b levels. There was no difference in serum TNF-a, lung extract TNF-a and IL-1b. NFkB activity IL-1b liver protein TNF-a liver protein MIP-2 liver protein Serum IL-1b Serum MIP-2 MIP-2 lung protein

untreated

PS-341 treated

p

2.96 ⫾ 0.08 84.0 ⫾ 8.6 467.7 ⫾ 79.8 240.7 ⫾ 54.9 36.3 ⫾ 2.7 4060.5 ⫾ 616.0 228.2 ⫾ 38.1

1.45 ⫾ 0.35 63.4 ⫾ 5.4 244.6 ⫾ 50.2 94.7 ⫾ 13.2 46.7 ⫾ 4.0 1304.5 ⫾ 803.4 86.9 ⫾ 58.6

0.002 0.03 0.02 0.01 0.02 0.01 0.03

ⴱ Results expressed as Mean ⫾ SD

Effect of hyperbarically oxygenatedperfluorochemial (HBO-PFC) with UW solution on preservation of rat small intestine

METHODS: We manufactured an air-tight pressure resistant tank which was made of stainless steel with high thermal conductivity. Rat’s ileal grafts were preserved in a custom-made silicon-gum bag with UW solution, which was steeped into the 5 atm HBO-PFC solution in the tank (Group P5). The tank was placed at 4 degrees C. After 24-hours preservation, measurement of tissue ATP content (luciferin / luciferase method: nmol/mg protein) and mucosal permeability (everted gut sac method measuring flux of fluorescent dextran: nl/min/cm), and histologic study (grading by Chiu’s score) were performed. These parameters in Group P5 were compared to grafts preserved in 1 atm oxygenated-PFC/UW solution (Group P1) and simple cold storage in UW solution (Group C). RESULTS: PO2 in UW solution after 24-hours preservation were 1942.0冎57.2, 722.2冎14.5, and 169.816.6 mmHg (Group P5, P1 and C, respectively).Graft tissue ATP concentration was significantly higher in Group 5P compare to that in Group P1 and Group C (Table). Mucosal hyperpermability was also ameliorated in grafts in Group P5.Histologic study showed well preserved mucosal structure in Group 5P. Comparison of various parameters after 24 hours preservation

Group P5 Group P1 Group C

ATP content (nmol/mg protein)

Mucosal permeability (nl/min/cm)

Histological grading (Chiu’s score)

57.3 ⫾ 8.1 26.6 ⫾ 1.9ⴱ 13.0 ⫾ 2.5ⴱ

19.0 ⫾ 2.2 23.6 ⫾ 2.4ⴱ 34.8 ⫾ 4.4ⴱ

0.8 ⫾ 0.5 1.0 ⫾ 0.5 2.4 ⫾ 0.6ⴱ

ⴱ p ⬍ 0.01 vs Group P5