A fulminant hepatic failure model in the rat: involvement of interleukin-1beta and tumor necrosis factor-alpha

The development of a fulminant hepatic failure (FHF) model is necessary for evaluating the efficacy of extracorporeal liver support systems. Recognizing the multifaceted functions of the liver, including synthesis and degradation, we investigated blood chemistry, histological findings, and survival rate in D-galactosamine (GalN)-intoxicated rats. The pathophysiologic response of inflammatory cytokines, interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), was also measured. Sprague-Dawley rats (200-300 g) were divided into two groups: GalN and saline injection. Rats were killed at 1, 3, 6, 12, 24, 36, 48, 72, and 168 hr after intraperitoneal injection of GalN (1.4 g/kg) or saline. In both groups, liver-specific markers, liver histology, and IL-1beta and TNF-alpha levels in blood and liver tissue were analyzed. In a second series of experiments, the survival rates were examined after two administrations of GalN at 1.0, 1.4 or 2.0 g/kg, at a 12-hr interval. In the GalN injection group, the liver-specific markers reached peak levels between 36 and 48 hr after injection. Histologically, hepatocellular necrosis was seen at 6-48 hr, followed by a regenerative phase occurring between 72 and 168 hr. IL-1beta and TNF-alpha levels in liver tissue peaked at 12 hr and 1 hr, respectively. The levels of these cytokines in blood, however, did not change significantly. The survival rates at day 7 for 1.0, 1.4 or 2.0 g/kg GalN injected twice were 77.8%, 16.7%, and 0%, respectively. These results suggest that single and double injection of GalN enable the development of reversible and irreversible FHF models. The results also indicate that IL-1beta and TNF-alpha are useful markers of liver injury.

A fulminant hepatic failure model in the rat: involvement of interleukin-1beta and tumor necrosis factor-alpha

The development of a fulminant hepatic failure (FHF) model is necessary for evaluating the efficacy of extracorporeal liver support systems. Recognizing the multifaceted functions of the liver, including synthesis and degradation, we investigated blood chemistry, histological findings, and survival rate in D-galactosamine (GalN)-intoxicated rats. The pathophysiologic response of inflammatory cytokines, interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), was also measured. Sprague-Dawley rats (200-300 g) were divided into two groups: GalN and saline injection. Rats were killed at 1, 3, 6, 12, 24, 36, 48, 72, and 168 hr after intraperitoneal injection of GalN (1.4 g/kg) or saline. In both groups, liver-specific markers, liver histology, and IL-1beta and TNF-alpha levels in blood and liver tissue were analyzed. In a second series of experiments, the survival rates were examined after two administrations of GalN at 1.0, 1.4 or 2.0 g/kg, at a 12-hr interval. In the GalN injection group, the liver-specific markers reached peak levels between 36 and 48 hr after injection. Histologically, hepatocellular necrosis was seen at 6-48 hr, followed by a regenerative phase occurring between 72 and 168 hr. IL-1beta and TNF-alpha levels in liver tissue peaked at 12 hr and 1 hr, respectively. The levels of these cytokines in blood, however, did not change significantly. The survival rates at day 7 for 1.0, 1.4 or 2.0 g/kg GalN injected twice were 77.8%, 16.7%, and 0%, respectively. These results suggest that single and double injection of GalN enable the development of reversible and irreversible FHF models. The results also indicate that IL-1beta and TNF-alpha are useful markers of liver injury.

In vitro and in vivo evaluation of albumin synthesis rate of porcine hepatocytes in a flat-plate bioreactor

Several configurations of extracorporeal bioartificial liver devices have been developed for the potential treatment of fulminant hepatic failure or as a bridge to liver transplantation. Recently, we developed a microchannel flat-plate bioreactor with an internal membrane oxygenator in which porcine hepatocytes are cultured as a monolayer on the bottom glass surface. In the present study, we investigated synthetic function of porcine hepatocytes in the bioreactor in both in vitro and in vivo flow circuit models. In vitro, albumin synthesis was stable in the bioreactor for up to 4 days of perfusion. In vivo, with the extracorporeal connection of the bioreactor to rat vasculature, porcine albumin was detectable for 24 h in the rat plasma. We also developed a simple mathematical model to predict the in vivo porcine albumin concentration in rat plasma. These results indicate that this configuration of a microchannel flat-plate bioreactor has potential as a liver support device and warrants further investigation.

Asymptomatic intrahepatic choledochal cyst associated with chronic active hepatitis C

A rare case of asymptomatic congenital choledochal cyst (Todani Type V) associated with chronic active hepatitis C is reported. A 45 year-old man was admitted for work-up of localized cystic dilatation of the intrahepatic bile ducts after effective interferon treatment for chronic active hepatitis C. Radiologic examination revealed localized cystic dilatation of the intrahepatic bile ducts in the atrophic left lobe. A left hepatic lobectomy was performed because malignancy had not been excluded. Macroscopic examination of the resected specimen revealed cystic dilatation of the intrahepatic bile ducts. Histologically, there was no evidence of malignancy. Hepatic lobectomy is the treatment of choice for Type V cysts if the disease is confined to a single lobe. Choledochal cysts should be excised to eliminate the potential for cholangitis, lithiasis, and carcinoma.

Pathophysiological response of cytokines and vasoactive agents in patients undergoing total gastrectomy

OBJECTIVE

To investigate the involvement of vasoactive agents, endothelin (ET)-1, and atrial natriuretic peptide (ANP), and the responses of cytokines in patients undergoing total gastrectomy.

DESIGN

Prospective study.

SETTING

University hospital, Japan.

SUBJECTS

20 patients with advanced gastric cancer who had undergone total gastrectomy with lymph node dissection.

INTERVENTIONS

Serum or plasma samples collected on the day before the operation, at the time of skin closure, and on postoperative days 1, 3, 5, and 7.

MAIN OUTCOME MEASURES

Concentrations of acute phase reactants, cytokines (interleukin (IL)-1, tumour necrosis factor (TNF) and interleukin (IL)-6), and vasoactive agents (ET-1 and ANP).

RESULTS

There were significant increases in concentrations of IL-6 and acute phase reactants postoperatively. ET-1 and ANP concentrations did not change significantly.

CONCLUSION

There was no correlation between concentrations of the vasoactive agents ET-1 and ANP, and those of acute phase reactants or cytokines in serum or plasma in patients undergoing total gastrectomy.

Up-regulation of oxygen-derived free radicals by interleukin-1 in hepatic ischemia/reperfusion injury

BACKGROUND

Oxygen-derived free radicals (FRs) are critical mediators of ischemia/reperfusion injury. Inflammatory cytokines have been shown to play important roles in tissue injury. To examine the relationship between FRs and interleukin-1 (IL-1) in hepatic ischemia/reperfusion injury, we used interleukin-1 receptor antagonist (IL-1ra) to block endogenous IL-1 production in a rat model of hepatic ischemia/reperfusion.

METHODS

Female SD rats were subjected to 30 min of hepatic ischemia followed by reperfusion. The animals were divided into two groups, control group and IL-1ra-treated group, according to the rinse solution. In both groups, FR production, histological changes, and interactions between leukocytes and endothelial cells were analyzed in the course of reperfusion.

RESULTS

In the control group, production of FRs increased significantly after 60 min of reperfusion. After 60 and 180 min of reperfusion, histological examination showed atrophy and degeneration of hepatocytes. Hepatic microcirculation demonstrated a marked increase in the number of leukocytes adherent to endothelial cells and of injured cells after reperfusion. In the IL-1ra-treated group, IL-1ra pretreatment markedly reduced FR production after 60 min of reperfusion, the number of leukocytes adherent to endothelial cells, and tissue injury.

CONCLUSION

These data clearly show an important role for IL-1 in the induction of FR production, leukocyte adhesion, and tissue injury after hepatic ischemia/reperfusion injury.

Interleukin 1 receptor blockade reduces tumor necrosis factor production, tissue injury, and mortality after hepatic ischemia-reperfusion in the rat

The inflammatory cytokines interleukin (IL) 1 and tumor necrosis factor (TNF) may play an important role in hepatic ischemia-reperfusion (I/R) injury. To study the role of IL-1 in hepatic I-R injury, we investigated the effect of pretreatment with IL-1 receptor antagonist (IL-1ra) on the production of IL-1, TNF, histological findings in the liver, and the survival rate for 7 days. Rats were subjected to 90 min of partial liver warm ischemia by clamping the vessels of the left and middle lobes. In the IL-1ra-treated group, IL-1ra was given 5 min before liver ischemia was induced. IL-1alpha and TNF levels were determined in blood and liver at 0, 30, 90, and 180 min after reperfusion. In a second experiment to determine the effect of IL-1ra pretreatment on survival rate, after 90 min of partial liver ischemia, the right lateral and caudate lobes were excised, leaving only the ischemic lobes. In both groups, IL-1alpha was undetectable in blood, but increased in liver tissue. TNF increased in both blood and liver tissue as reperfusion time increased. Histological evidence of tissue injury was minimal in the IL-1ra-treated group. Furthermore, in the IL-1ra-treated group, the production of TNF decreased in both blood and liver tissue compared with the nontreated group. Survival rates in the IL-1ra-treated and nontreated group were 80% and 30%, respectively. The data demonstrated that the production of IL-1 and TNF increases in hepatic I-R injury and that pretreatment with IL-1ra protects the liver from ischemic insult, indicating an important role for IL-1 in I-R injury.

[Microcirculatory disturbances after surgical insults--important role of inflammatory cytokines]

Microcirculatory disturbances in the gastric mucosa was investigated in rats after thermal injury using intravital video microscopy. Mucosal blood flow decreased significantly 5 hrs after thermal injury and increased neutrophil-endothelial cell interaction was observed at the same time. Zymosan stimulated-free radical production from peripheral blood was also increased and acute gastric mucosal lesion (AGML) appeared 5 hrs after thermal injury. These data suggest that neutrophil-endothelial cell interaction and increased free radical production induce AGML formation and that microcirculatory disturbance is one of the main reasons for organ failure after surgical insults. The role of inflammatory cytokines in hepatic microcirculatory disturbance was also studied in endotoxin-injected rats using IL-1 receptor antagonist (IL-1Ra) or TNF binding protein (TNFbp). Pretreatment with IL-1Ra or TNFbp significantly improved hepatic microcirculatory disturbance and reduced both the number of leukocytes adhered to the sinusoidal wall and the number of injured cells as well. These data suggest that inflammatory cytokines play a crucial role in microcirculatory disturbance after surgical insults by promoting neutrophil-endothelial cell interaction and systemic excessive inflammation.