Maria Piera Panozzo

CYTOKINES AND THE PROGRESSION OF LIVER DAMAGE IN EXPERIMENTAL BILE DUCT LIGATION

1. Cytokines are soluble factors whose action has been documented in physiological and pathological conditions. Some may be involved in the pathogenesis of cholestasis, whether of acute or chronic origin.

An Unidentified Pancreatic Cancer Cell Product Alters Some Intracellular Pathways of Glucose Metabolism in Isolated Rat Hepatocytes

In this study we assessed whether conditioned media from a human pancreatic cancer cell line (MIA PaCa 2) can interfere with some intracellular pathways involved in glucose metabolism in isolated rat hepatocytes. The hepatocytes, isolated from Male Wistar rats, were incubated with MIA PaCa 2-conditioned or nonconditioned media. Conditioned and nonconditioned hepatocytes were run for 120 min in the presence or absence of insulin (100 mM) and were sampled at fixed time intervals. Supernatant glucose levels decreased to a similar extent over time in both conditioned and nonconditioned hepatocytes, while lactate levels significantly increased in nonconditioned hepatocytes with respect to conditioned hepatocytes. A pyruvate kinase activity increase was observed only in nonconditioned hepatocytes and was biphasic in nature, since this increased activity was detected both after a few and after 30 min following insulin stimulation. The cyclic AMP level increase was significantly higher in conditioned than in non-conditioned hepatocytes. It appears that MIA PaCa 2 cells produce a factor(s) that may interfere with one of the insulin-mediated intracellular pathways of glucose metabolism, namely, glycolysis. This detrimental effect on glycolysis is supported by the blunted rise in lactate concentration in the medium after the glucose challenge. This substance(s) probably transfers its signal inside the target cells, activating the adenylate cyclase pathway. These results support the hypothesis that pancreatic cancer is the cause rather than the consequence of diabetes mellitus.

ALTERED LIPID PEROXIDATION/GLUTATHIONE RATIO IN EXPERIMENTAL EXTRAHEPATIC CHOLESTASIS

1. Lipid peroxidation can occur in the presence of a cellular antioxidant‐oxidant imbalance, but the role of lipid peroxides in cholestasis is not well understood.

Renal functional alterations in extrahepatic cholestasis: can oxidative stress be involved?

Renal function may be compromised by extrahepatic cholestasis. In this context, the nephrotoxic role of bile salts is well known. Recently, however, it has been claimed that other factors, such as lipid peroxides, are involved. We therefore created bile duct ligation in 40 Sprague-Dawley rats. During the follow-up (from 1 to 28 days), significant variations were found in liver histological parameters, but not in renal morphology. Fourteen days after ligation, significant increases were found in serum and urinary thiobarbituric-acid-reactive species and phospholipase A2 (indirect indices of lipid peroxidation), whereas 8-10 days after ligation, a significant decrease was observed in erythrocytic and hepatic GSH levels. The variations in urinary thiobarbituric-acid-reactive species and in phospholipase A2 were not correlated with concomitant variations in the sera. Urinary lipid peroxides were directly correlated with the degree of liver morphological alterations and inversely with circulating GSH. Urinary outputs of lipid peroxides, phospholipase A2 and N-acetyl-glucosaminidase were correlated with each other. These results suggest that there is an imbalance in the oxidative-antioxidant hepatic system in experimental extrahepatic cholestasis. The reduced bioavailability of blood GSH may alter the oxidative equilibrium in other organs, such as the kidney, triggering and favoring the lipoperoxidative cascade.

Effects of pancreaticobiliary duct obstruction on the exocrine and endocrine rat pancreas.

Experimentally, biliary obstruction can produce morphological and functional changes in the pancreatic gland, whereas pancreatic obstruction may have short-term (hyperamylasemia, pancreatic edema, and lysosomal hydrolase redistribution) or long-term (acinar cell atrophy and interstitial fibrosis) effects. We created a pancreaticobiliary duct obstruction in rats to evaluate (a) exocrine and endocrine anatornobiochemical pancreatic modifications; (b) structural and functional liver alter ations; and (c) the relationship, if any, between the alterations found in the two organs. Forty-five male SpragueDawley rats were subdivided on the basis of period of obstruction (from 1 to 28 days). In each rat serum we evaluated amylase, cholestatic and cytolytic indices, and glucose. In frozen pancreatic samples we measured insu lin, glucagon, and DNA; in the liver the DNA content was determined. Histologically, ductal dilation and proliferation were evaluated for the liver, zymogen granules, and Langerhans islets, and atrophy for the pancreas. Fibrosis was evaluated for both the liver and the pancreas. Shortterm common pancreaticobiliary duct ligation caused an increase in serum amylase levels and mild pancreatic edema. Longer-term obstruction had either similar or different effects on the two organs. In the pancreas it caused fibrosis and exocrine and endocrine atrophy, but not acute pancreatitis. In the liver the main phenomena observed were fibrosis, ductal dilation, and proliferation.

Hepatic changes and serum ferritin in pancreatic cancer and other gastrointestinal diseases: the role of cholestasis

Serum ferritin, prealbumin, pseudocholinesterase, α-1-antitrypsin and caeruloplasmin were determined in control subjects and patients with pancreatic cancer, chronic pancreatitis or extra-pancreatic disease mainly of gastrointestinal origin, in order to investigate the different hepatic changes which influence serum ferritin in chronic pancreatic and other digestive diseases. Increased circulating ferritin was found in pancreatic cancer and extra-pancreatic disease when compared to controls. Correlations were detected between ferritin and the other proteins investigated and between ferritin and total bilirubin, alkaline phosphatase and alanine aminotransferase. Multiple regression analysis demonstrated that cholestasis accounts for 45% of circulating ferritin, the acute-phase response accounted for 18% and decreased liver function accounted for 11%. We conclude that the increase in serum ferritin in chronic pancreatic and other gastrointestinal diseases largely depends on liver changes, with cholestasis probably playing a primary role.

Serum phospholipase A2 activity in chronic pancreatic diseases.

This study was performed to investigate the phospholipase A2 (PLA2) serum activity in patients with chronic pancreatic disease. PLA2, elastase-1, total, and pancreatic isoamylase were evaluated in 40 control subjects, 28 patients with pancreatic cancer, 51 with chronic pancreatitis, and 36 with extrapancreatic diseases, mainly of gastrointestinal origin. Elastase-1, PLA2, and pancreatic isoamylase were increased in 56%, 25%, and 15% of patients with pancreatic cancer, and in 40%, 31%, and 41% of subjects with chronic pancreatitis. All four enzymes gave pathological values in a number of patients with extrapancreatic diseases. We conclude that the diagnostic efficacy of phospholipase A2 in chronic pancreatic disease is similar to that of other well known pancreatic enzymes, with an unsatisfactory sensitivity and specificity.

Is CA 242 Really a New Tumour Marker for Pancreatic Adenocarcinoma

CA 242, a sialylated carbohydrate epitope situated on the same macromolecule as CA 50 has been proposed as a new tumour marker for pancreatic cancer (PC). The aims of the present study were: (1) to evaluate serum CA 242 versus CA 19-9 in PC patients, and (2) to assess whether these markers can predict tumour spread or patient survival. We studied 59 healthy controls, 27 PC patients, 12 chronic pancreatitis cases, 107 with extra-pancreatic gastrointestinal tumours, 30 with benign jaundice and 24 with benign extra-pancreatic gastrointestinal diseases. Mean CA 242 values were significantly higher in PC than in any other group; CA 19-9 showed a similar pattern. The best diagnostic efficacy (ROC curves analysis) in diagnosing PC was 86% for CA 242 and 84% for CA 19-9, using cut-off values of 60 and 80 U/ml, respectively. In PC, serum levels of both markers were unrelated to tumour spread or size; in PC patients with high levels of CA 242 or CA 19-9 survival was significantly shorter. CA 242 and CA 19-9 were correlated both when considering all the patients together (r = 0.962, p < 0.001) and PC alone (r = 0.880, p < 0.001). Given the very close relationship between CA 242 and CA 19-9, we tested for cross-reactivity between CA 242 antigen and CA 19-9 antibody: CA 242 antigen with CA 19-9 antibody produced a similar curve to CA 242 antigen and its corresponding antibody. In conclusion, CA 242 showed similar diagnostic values to CA 19-9 in assessing PC patients; both seem unrelated to tumour size or spread, but seem to predict survival. Their remarkably similar behaviour is due to cross-reactivity between CA 242 antigen and CA 19-9 antibody, so CA 242 cannot, in our opinion, be considered a new tumour marker for PC.

Effect of octreotide acetate on pancreatic exocrine and endocrine functions after pancreatoduodenal resection.

In view of forecasting the effect of octreotide acetate (Sandostatin) in preventing fistula formation after pancreatic surgery, 9 patients, who had pancreatoduodenectomy 8-12 days before, underwent a 2-day study. The first day, by means of a catheter located in the jejunal loop separately anastomosed to the pancreatic remnant, basal and after secretin stimulation pancreatic secretion was evaluated. During the 2nd day the possible inhibitory effect of octreotide on basal and stimulated secretion was investigated. Under the experimental conditions of the study Sandostatin showed little effect on the water and bicarbonate increase as stimulated by secretin. A greater hormone inhibitory effect on amylase production and pancreatic endocrine function was seen. On the basis of these results the use of Sandostatin can hardly be seen as useful in preventing fistula formation after pancreatic resection.

Increased Serum Phospholipase A2 Activity in Advanced Chronic Liver Disease as an Expression of the Acute Phase Response

Phospholipase A2 (PLA2) modifications were investigated in patients with acute and chronic liver diseases, PLA2 variations were related to indices of liver function as well as to parameters of the acute phase response. Serum PLA2 activity modifications were fluorimetrically measured in 105 patients affected by acute and chronic liver diseases or extra-hepatic diseases. One-way ANOVA demonstrated a significant difference among groups (F = 4.53, P < 0.001); Bonferronis test for pairwise comparisons showed that patients with hepatocellular carcinoma had higher mean values than subjects with benign extra-hepatic diseases (P < 0.01) and mild chronic liver disease (P < 0.05). Multiple regression analysis, performed choosing PLA2 as the dependent variable and blood urea nitrogen, C-reactive protein, alkaline phosphatase and alpha 1-fetoprotein as predictor variables was significant (multiple R = 0.7056, multiple R2 = 0.4978, F = 15.36, P = < 0.0001). The standardized regression coefficients found to be significant were those of C-reactive protein, blood urea nitrogen and alpha 1-fetoprotein. In conclusion, in patients with chronic liver disease, serum PLA2 activity increases parallel to disease severity and accompanies the expression of proteins of the acute phase response that, like PLA2 activity, increase in serum while liver synthesis declines.