Graded experimental acute pancreatitis: monitoring of a renewed rabbit model focusing on the production of interleukin-8 (IL-8) and CD11b/CD18.

OBJECTIVE: To establish and monitor a rabbit model of graded severity of acute pancreatitis to test the hypothesis that interleukin-8 (IL-8) and the adhesion molecule complex CD11b/CD18 are involved in the development of systemic complications in severe acute pancreatitis. METHODS: Acute pancreatitis induction in rabbits by duct ligation with or without infusion of 5.0% or 0.5% chenodeoxycholic acid or 0.9% saline. Control animals underwent laparotomy. The animals were monitored biochemically, histologically and immunohistochemically. RESULT: Increased serum levels of IL-8, tumour necrosis factor alpha (TNF-alpha), amylase and lipase were found in the chenodeoxycholic acid groups when compared with the saline, duct-ligated or control groups. Leukopenia, hypocalcaemia, and hyperglycaemia were marked in the 5.0% chenodeoxycholic acid group as compared to the saline, duct-ligated and control groups. Histologically, the 5.0% chenodeoxycholic acid group manifested a significant degree of pancreatic necrosis and neutrophil infiltration. The lungs of these animals showed acute lung injury and a significant up-regulation of CD11b/CD18. IL-8 was produced in pancreatic acinar and ductal cells. A significantly large output of ascitic fluid was seen in the 5.0% chenodeoxycholic acid group. CONCLUSION: The rabbit models of acute pancreatitis are reliable in that enzymatic and histological evidence of acute pancreatitis with or without systemic complications developed. IL-8 is produced locally in pancreatic acinar and ductal cells and significantly increased in peripheral blood during severe but not mild pancreatitis. The expression of the adhesion molecule complex CD11b/CB18 is significantly increased in lung tissue during severe acute pancreatitis with acute lung injury. IL-8 and CD11b/CB18 are involved in the pathogenesis of severe acute pancreatitis but not of mild oedematous pancreatitis.

Effects of laparotomy vs pneumoperitoneum on the hepatic catabolic stress response in ambulatory and stationary settings in pigs.

BACKGROUND: We recently demonstrated that laparoscopic cholecystectomy is followed by a much smaller hepatic catabolic stress response than conventional cholecystectomy. It is not known what is responsible for this difference. METHODS: Thirty pigs were randomly allocated to the following five treatment groups: (1) laparotomy, (2) pneumoperitoneum, (3) pneumoperitoneum with insertion of four trocars, (4) laparotomy, (5) pneumoperitoneum. Groups 1-3 were operated on in an ambulatory setting, whereas groups 4 and 5 were operated on in a stationary setting. Urea synthesis, as quantified by functional hepatic nitrogen clearance, and the response of stress hormones and cytokines were assessed. RESULTS: Laparotomy increased the functional hepatic nitrogen clearance by 195% (p < 0.001); pneumoperitoneum and trocars increased it by 145% (p < 0.001); and pneumoperitoneum alone increased it by 113% (p < 0. 001). The difference between laparotomy and both pneumoperitoneum groups was significant. If the stress factor of ambulatory surgery was eliminated, the increase in functional hepatic nitrogen clearance was reduced to 87% (p < 0.01) after laparotomy and 38% (NS) for animals subject to pneumoperitoneum. There were significant differences in concentrations of stress hormones, tumor necrosis factor alpha, and interleukin 8 among groups intra- and postoperatively. CONCLUSIONS: The magnitude of the postoperative hepatic stress response after laparotomy compared to pneumoperitoneum with and without insertion of trocars seems to be caused by the greater trauma to the abdominal wall. Furthermore, an ambulatory setting seems to be an important postoperative stress factor in itself.

Biliary parasites.

Parasitic diseases of the biliary tract occur frequently in tropical and subtropical areas and cause high morbidity and mortality. In general, neither the clinical presentation nor the general laboratory findings are sufficiently unique to raise the possibility of a parasitic biliary infestation in the mind of the surgeon. Once considered, however, the presence of a parasitic biliary infestation is easily confirmed. Most commonly this is accomplished by the identification of the parasite in stools or duodenal contents. Ultrasonography, CT and MRI are not only important in the diagnosis of parasitic biliary diseases but also in the follow-up and surveillance. ERCP is an excellent diagnostic tool for demonstrating the presence of parasites in the biliary tree. Furthermore, ERCP is also used in the therapy of biliary parasitic infestations and carries less morbidity and mortality than the surgical approach. Surgery is only indicated in complicated cases. Mechanisms that may be effective against parasites include: antibodies; cytotoxic T cells; T-cell-induced activated macrophages; natural killer cells, and a variety of cells that mediate antibody-dependent cell-mediated cytotoxicity and modulators of the immune system such as cytokines. Future research has to focus on the importance of these mechanisms for the immune evasion by parasites.

Sodium fusidate and the cytokine response in an experimental model of acute pancreatitis.

BACKGROUND: New therapies designed to downregulate the aberrant immune response associated with severe acute necrotizing pancreatitis (ANP) are being increasingly investigated in different experimental models of ANP. The aim of this study was to test the potential effects of sodium fusidate on the course of severe ANP in rabbits. METHODS: ANP was induced in 20 rabbits by retrograde injection of 5 per cent chenodeoxycholic acid into the pancreatic duct followed by duct ligation. The rabbits were allocated to pretreatment with intravenous physiological saline or sodium fusidate 80 mg/kg 30 min before the induction of ANP. Levels of serum amylase, lipase, tumour necrosis factor (TNF) alpha, interleukin (IL) 8, glucose and calcium, and leucocyte count were measured every 3 h for a total of 12 h. At the end of the experiment, ascitic fluid was collected and the pancreatic, lung and kidney tissues were obtained for histological examination. RESULTS: Pretreatment with sodium fusidate reduced the mortality rate from six of ten to three of ten (P < 005) and reduced the output of ascitic fluid from 5 2 to 2.0 ml/h (P < 0001). Serum levels of TNF-alpha and IL-8 were reduced significantly in the treated group from 5 min up to 9 h after induction of ANP. The leucopenia observed after 3 h in the untreated group was not significantly improved in the group treated with sodium fusidate (P = 0.055). By contrast, both treated and untreated rabbits had similar biochemical changes including levels of amylase, lipase, glucose and calcium as well as similar histological changes in the pancreas and lungs. CONCLUSION: Pretreatment with sodium fusidate resulted in a considerable reduction in mortality rate and ascitic fluid output in rabbits with bile-induced ANP, probably by lowering the TNF-alpha and IL-8 blood levels. However, pretreatment with sodium fusidate did not alter the local or systemic manifestations of ANP. Thus, cytokines other than TNF-alpha and IL-8 are likely to mediate the local and systemic symptoms of ANP.

Systemic and cell-mediated immune response after laparoscopic and open cholecystectomy in patients with chronic liver disease. A randomized, prospective study.

BACKGROUND: As impaired immune function observed in cirrhotic patients is known to increase the risk of postoperative complications, the immunological response to surgery was investigated. METHODS: Twenty-eight patients with postnecrotic liver cirrhosis or chronic hepatitis C and symptomatic gallstone disease were randomly allocated to laparoscopic (LC) or open cholecystectomy (OC). Changes in concentrations of cytokines (TNF-alpha, IL-1beta, IL-6, IL-8 and IL-10) were followed and the effect of surgical trauma on the distribution of lymphocyte subpopulations (CD3, CD4, CD8, CD16 and CD19) and NK cell cytotoxicity were measured. RESULTS: After OC a decrease in circulating CD3 (p < 0.05) and CD4 (p < 0.05) and an increase in CD19 (p < 0.05) cells were detected in contrast to LC after which only CD16 cells decreased (p = 0.05). The number of CD3 cells was higher after LC than after OC (p < 0.01), whereas the number of CD19 cells was higher after OC than after LC (p < 0.01). NK cell cytotoxicity was reduced after LC (p < 0.05). In cirrhotic patients circulating cytokines were unaffected by OC, whereas TNF-alpha (p < 0.05) and IL-1beta (p < 0.05) were reduced after LC. In chronic hepatitis IL-1beta decreased after OC (p = 0.05) and IL-10 was significantly higher after LC than following OC (p < 0.05). CONCLUSION: The immune response is less pronounced after a laparoscopic procedure compared to a conventional approach in patients with chronic liver disease.

Protein C activation during the initial phase of experimental acute pancreatitis in the rabbit.

BACKGROUND: Disturbances of coagulation and fibrinolysis are well-known systemic effects of acute necrotising pancreatitis (ANP). The purpose of this experimental study was to evaluate the initial events in the haemostatic activation during ANP in an animal model with relevance to the human situation. METHODS: ANP was introduced in 7 rabbits by infusion of chenodeoxycholic acid in the pancreatic duct. Seven rabbits served as sham-operated controls. Serial measurements of coagulation variables (prothrombin time, activated partial thromboplastin time, FVII activity, fibrinogen, tissue factor activity), anticoagulant proteins (protein C, antithrombin) and fibrinolytic factors (tissue plasminogen activator, plasminogen activator inhibitor-1) were performed for 5 h. RESULTS: ANP was confirmed by elevated serum amylase, development of ascites, and histological changes of the pancreas. A moderate activation of the coagulation system was found in both study groups. A significant decrease in protein C concentration from 1 h after the induction of ANP was found, whereas the response of antithrombin and the inhibition of the fibrinolytic system were similar in the 2 study groups. Microthrombosis of the lungs or kidneys was found in 2 rabbits with ANP. CONCLUSION: An immediate activation of protein C is a specific characteristic of the haemostatic activation in ANP in rabbits. This activation has not been described previously and the possible therapeutic implications ought to be studied.

Postoperative hepatic catabolic stress response in patients with cirrhosis and chronic hepatitis.

Open (OC) or laparoscopic (LC) cholecystectomy is considered a relative contraindication in patients with liver cirrhosis. The effect of LC and OC on the hepatic catabolic stress response was studied in patients with postnecrotic liver cirrhosis and chronic hepatitis to define the most suitable procedure from a metabolic point of view. Altogether 14 patients with cirrhosis and 14 with chronic hepatitis were randomized to LC or OC (n = 7 in each group). The increase in the functional hepatic nitrogen clearance (FHNC) was quantified. Changes in glucose, insulin, glucagon, cortisol, epinephrine, norepinephrine, and prostaglandin E(2) (PGE(2)) were observed. There was no difference in FHNC between LC and OC in any of the patients. Among cirrhotic patients OC caused a 132% increase in FHNC (p < 0.05) and among the hepatitis patients a 69% increase (p < 0.05). In contrast, there was no significant increase following LC in any of the patients. OC increased fasting glucose and insulin in the hepatitis patients (p < 0.01 and p < 0.001, respectively) and in the cirrhosis group (p < 0.01 and p < 0.05, respectively). Alanine stimulation increased glucose in hepatitis patients after OC (p < 0.05) and after LC (p < 0.01). Stimulated glucagon increased after OC in the hepatitis group (p < 0.05). During stimulation cortisol was higher following LC in hepatitis patients (p < 0.01) and cirrhotic patients (p < 0.05). Fasting PGE(2) was down-regulated after LC in hepatitis patients (p < 0.05) and cirrhotic patients (p < 0.01) and after OC in the hepatitis group (p < 0.001). FHNC is similar after LC and OC. Thus from a metabolic point of view, LC has no advantage over OC.

A monoclonal anti-interleukin 8 antibody (WS-4) inhibits cytokine response and acute lung injury in experimental severe acute necrotising pancreatitis in rabbits.

BACKGROUND: Interleukin 8 (IL-8) has recently been proposed to have an important role in mediating the development of the systemic sequelae associated with severe acute pancreatitis. AIMS: To define the role of IL-8 in acute pancreatitis by neutralising its effects with a monoclonal anti-IL-8 antibody (WS-4), in a rabbit model of severe acute pancreatitis. METHODS: Acute pancreatitis was induced by retrograde injection of 5% chenodeoxycholic acid into the pancreatic duct and duct ligation. Twenty rabbits were divided equally into two groups: acute pancreatitis controls received physiological saline and the treated group received WS-4, 30 minutes before induction of acute pancreatitis. RESULTS: Pretreatment of animals with WS-4 resulted in significant down regulation of serum IL-8 and tumour necrosis factor alpha (TNF-alpha) from three to six hours after induction of acute pancreatitis (p = 0.011 and 0.047 for IL-8 and 0.033 and 0.022 for TNF-alpha, respectively). In addition, a significant reduction in the CD11b and CD18 positive cells and the amount of interstitial neutrophil infiltration in the lungs from WS-4 treated animals was seen. In contrast, WS-4 did not alter the amount of pancreatic necrosis and the serum concentrations of amylase, lipase, calcium, and glucose. CONCLUSION: WS-4 cannot change the amount of pancreatic necrosis induced by injection of 5% bile acid, but does reduce the acute lung injury, presumably through inhibition of circulating IL-8 and TNF-alpha, and CD11b/CD18 in lung tissue. Therefore, a role of IL-8 in the progression of acute pancreatitis and the development of its systemic complications is suggested.