Three-dimensional structure of the rat pancreatic duct in normal and inflammated pancreas

We observed the corrosion casts of the Wistar rats' pancreatic ducts with scanning electron microscopy (SEM), and their conventionally fixed pancreatic tissue with SEM and transmission electron microscopy (TEM). These findings revealed the following facts about the three-dimensional structure of pancreatic duct. (1) The interlobular and intralobular ducts branch like a tree, and the intercalated ducts wind and fork into two branches, although parts of the intercalated ducts anastomose with each other. The intercellular secretory canaliculi extend from the central lumina, which run straight through the center of the acini, finally approaching close to the basement membranes of acini. (2) The lumina of pancreatic ducts (i.e., the interlobular up to the intercalated ducts) are cylindric and have smooth surfaces. The luminal surface of each epithelial cell, however, is decorated by numerous microvilli and a single cilium. The length of the latter tends to be short in proportion to the diameter of pancreatic duct. Moreover the epithelial cell surfaces, which border each central lumen, have various densities of microvilli. (3) The intraductal cilium core is provided with nine microtubules, which is different from the number of microtubules encountered within the cilium core of uterine tube or bronchial epithelium. The number of microtubules in the cross-sectioned intraductal cilia decreases toward the distal portion of cilia. SEM and TEM observations on WBN/Kob rats' pancreatic ducts suggest that increased pancreatic ductal pressure causes the helical shape of the pancreatic ductal lumen. Such a helical form might also be caused by the protrusion of epithelial cell boundaries into their lumen and the hypertrophy and hyperplasia of epithelial cells, thus leading to the formation of numerous depressions equipped with elongated cilia.

[Risk factors of infected pancreatic necrosis, its microbiology and antibiotic treatment]

Acute pancreatitis is associated with greater and smaller necrosis in 20% of the cases. The lethality rate of sterile and infected necrosis is 10 and 15-40%, respectively. The results of a retrospective and a prospective study in acute pancreatitis have been analyzed in this study. Twenty patients suffering from infected necrosis due to acute necrotising pancreatitis were selected into the retrospective study. They were divided into two groups: Group 1 (N = 10) survivors, Group 2 (N = 10) those who died. The fate of patients was determined by their age, the severity of pancreatitis, and the effectiveness of the operation. In a prospective study 63 patients were operated due to benign pancreatic disease with fluid collection. Microbiological samples were taken during surgery in every case. It could be stated that the Enterobacteriaceae spp. play the principal role in the infection, and the anaerobic bacteria occur sporadically. The omission of bacteriological sample taking during surgery frustrates the targeted antibiotic treatment. The blood culturing may have useful contribution. The targeted antibiotic therapy based on relevant microbiological sample taking is substantial complementary of the surgical intervention in the treatment of the inflammatory pancreatic diseases.

Beneficial effects of L-2-oxothiazolidine-4-carboxylate on cerulein pancreatitis in mice

BACKGROUND & AIMS

Disturbances of the thiol metabolism of acinar cells may play a role in the pathophysiology of acute pancreatitis. Cerulein-induced pancreatitis causes depletion of glutathione. The entire pancreatic thiol status was assessed in this model. The potential benefit of augmentation of pancreatic glutathione by L-2-oxothiazolidine-4-carboxylate (OTC) for the course of pancreatitis was determined.

METHODS

Mice were treated with cerulein (50 microg/kg) and with or without administration of OTC (6.5 and 20 mmol/kg, respectively). Pancreatic tissue was analyzed for reduced and oxidized glutathione, nonprotein thiol, mixed disulfide, protein thiol, and protein disulfide. Histopathology and serum amylase were also assessed.

RESULTS

Levels of all thiol compounds were altered profoundly at a different rate during pancreatitis. OTC caused an increase of 60% in pancreatic glutathione. Its administration at 20 mmol/kg attenuated the decrease of pancreatic glutathione and protein thiol until 8 hours and blunted the cerulein-induced increase in amylase activity and histopathologic damage. At 6.5 mmol/kg, OTC failed to show effects on all parameters.

CONCLUSIONS

OTC administered in a prophylactic protocol dose-dependently exerted beneficial effects in cerulein-induced pancreatitis in mice despite only transient influence on pancreatic thiol compounds. Thiols (e.g., reduced glutathione) and their corresponding disulfides are critically involved in the pathophysiology of cerulein-induced pancreatitis.

Pancreatic fibrosis in experimental pancreatitis induced by dibutyltin dichloride

BACKGROUND & AIMS

Regulatory mechanisms in chronic pancreatitis finally resulting in pancreatic fibrosis cannot be studied sufficiently in human pancreas. Results of a new pancreatitis model in rats suitable for investigation of the processes leading to pancreatic fibrosis are presented.

METHODS

Experimental pancreatitis was induced by intravenous application of 8 mg/kg body wt dibutyltin dichloride. Pancreatitis was characterized by histology, serum parameters, and immunohistochemistry, detecting inflammatory cells. Gene expression of collagen type I and transforming growth factor beta1 was shown by Northern blot analysis.

RESULTS

Dibutyltin dichloride induced an acute edematous pancreatitis within 24 hours. Extensive infiltration with mononuclear cells could be observed after day 7 followed by the development of fibrosis. Parallel to the cell infiltration, an upregulation of messenger RNA-encoding collagen type I and transforming growth factor beta1 could be shown. An active inflammatory process could be shown until the end of the observation period, i.e., 2 months.

CONCLUSIONS

The findings suggest that dibutyltin dichloride-induced pancreatitis in rats is suitable to study cellular interactions and mediators involved in the development of pancreatic fibrosis.

A prospective evaluation of cytology from biliary strictures

BACKGROUND

Bile duct strictures may be benign or malignant. A definite diagnosis is desirable to advise patients of their prognosis and to identify any amenable to curative surgery.

AIMS

To compare different methods of cytology sampling from biliary strictures and evaluate the use of cytology in this context.

PATIENTS AND METHODS

In a prospective study 54 patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) had cytology samples obtained as follows: (1) biliary stricture brushings, (2) from the screw thread of a "Soehendra stent retriever" inserted through the stricture, (3) from the proximal end of a blocked biliary stent, and (4) cellular material spun down from a 20 ml specimen of bile. Examination of slides and rinsings was performed by an expert cytologist who graded them for the adequacy of the sample and for evidence of malignancy.

RESULTS

Prolonged follow up disclosed malignancy in 52 of the 54 cases, the other two being chronic pancreatitis. Bile samples provided adequate cytology samples in 44%, the Soehendra stent retriever in 70%, retrieved stents in 84%, and cytology brush sampling in 96%. Overall, 28 malignancies were detected by cytology, including 14 of 28 pancreatic carcinomas and 12 of 16 cholangiocarcinomas. Twenty two of the malignancies were detected by brush sampling and the other methods added a total of another six cases.

CONCLUSIONS

Cytology sampling is best done by brushing the biliary stricture. Cytology sampling can confirm the diagnosis in 75% of cholangiocarcinomas and 50% of pancreatic carcinomas. The techniques involved are simple to perform and should be routine clinical practice whenever potentially malignant biliary strictures are encountered at ERCP.

Lipoprotein lipase deficiency with pancreatitis in mink: biochemical characterization and pathology

A severe hyperlipemia in mink, with a pattern that suggested recessive inheritance, was observed at a farm in Norway. On a normal mink diet, affected animals had grossly elevated levels of plasma triglycerides which decreased towards normal on a low-fat diet. Normal minks had the main part of their plasma cholesterol in the HDL fraction. Affected minks, although severely hypertriglyceridaemic, had almost normal levels of both LDL and HDL. Affected minks frequently had lipogranulomas in the mesentery and the pancreas. The lipogranulomatous tissue contained spaces filled with an amorphous, sudanophilic substance with many foamy macrophages in the fibrous tissue between the lesions. Separation of postheparin plasma on heparin-agarose revealed that the affected minks had no detectable lipoprotein lipase activity but normal activity of hepatic lipase. Both normal and affected minks had inactive lipoprotein lipase protein in pre- and post-heparin plasma. This protein, which eluted before the active lipase from heparin-agarose, probably corresponds to lipase monomers. The presence of lipoprotein lipase mass in the affected minks, but no activity, indicates that there might be a point mutation in the lipase gene. The minks provide a new animal model for studies on pancreatitis induced by hypertriglyceridemia and on lipoprotein metabolism in the lipoprotein lipase-deficient state and show features similar to those found in human hyperlipoproteinemia type I.

Relationship between the presenting symptoms and age at diagnosis in alcoholic and nonalcoholic chronic pancreatitis: analysis of 164 patients

OBJECTIVE

To study the different forms of presentation, patient age, delay in diagnosis and incidence of calculi in alcoholic and nonalcoholic chronic pancreatitis.

METHODS

We have studied 130 men and 34 women diagnosed as having chronic pancreatitis on the basis of clinical criteria and morphological and/or functional tests.

RESULTS

Alcohol was the most common cause of chronic pancreatitis in men (89.1%) existing a significant difference with respect to women (p < 0.05). The mean age of the patients with alcoholic chronic pancreatitis was 45.6 +/- 11.3 years and that of patients presenting nonalcoholic chronic pancreatitis was 54.5 +/- 11.5 years (p < 0.01), the latter showing a bimodal distribution. The ages of the patients in whom the presenting symptom was abdominal pain and acute inflammatory episodes were 43.9 +/- 12.8 and 45.3 +/- 13.5 years, respectively, significantly lower (p < 0.05) than the age of patients in whom presentation was signaled by the onset of diabetes or diarrhea (53.1 +/- 11.2 and 61.2 +/- 12.9 years, respectively). Statistically significant differences existed in the delay in diagnosis when comparing the patients before and after 1985 (12.3 +/- 14.5 years, range 0 to 50 years, versus 0.42 +/- 0.9 years, range 0 to 5 years; p = 0.005). At diagnosis, 14.3% of the patients whose presenting symptom was acute pancreatitis had pancreatic calculi, versus 42.2% of those who reported abdominal pain as the first indication.

CONCLUSIONS

Alcoholic chronic pancreatitis predominates in men. Nonalcoholic chronic pancreatitis presents two peaks of prevalence. A substantial number of patients may remain pain-free up to diagnosis. Calculi are not uncommon during the initial period of chronic pancreatitis when pain is the presenting symptom, either in the form of isolated episodes of abdominal pain or attacks of acute pancreatitis.

[Duodenum preserving resection of the head of the pancreas: a standard procedure in chronic pancreatitis]

Duodenum-preserving resection of the head of the pancreas was developed 25 years ago by Beger. This procedure is indicated in patients suffering from chronic pain in combination with inflammation of the head of the pancreas, common bile duct obstruction, pancreatic duct obstruction and/or obstruction of the retropancreatic vessels. At the Inselspital in Berne, 74 patients underwent this operation between 1993 and 1996. The median length of the operation was 380 min, with the need for transfusion in a median of 0 units (0-6). There was no postoperative mortality. Total postoperative morbidity was 13%. One patient needed relaparotomy on day 17 for small bowel obstruction. Median length of hospital stay was 11 days. Postoperatively, two patients developed diabetes. Duodenum-preserving resection of the head of the pancreas represents an organ-preserving principle of surgery. This procedure treats the complications of chronic pancreatitis and provides long-term pain relief in more than 80% of patients.

Effects of green tea catechins (Polyphenon 100) on cerulein-induced acute pancreatitis in rats

Effects of green tea catechins (GTC) on cerulein-induced acute pancreatitis in rats were examined. The acute pancreatitis induced by cerulein (cerulein pancreatitis) was characterized by interstitial edema and vacuolation. When cerulein pancreatitis was induced, prior administration of 0.1% GTC in drinking water for 1 week before the induction significantly decreased the wet weight of the pancreas, the serum level of amylase, and the tissue concentration of lipid peroxides in the pancreas compared with those in nonmedicated rats supplied with plain tap water only. Furthermore, the pancreatic tissue alterations of the medicated rats were milder than those of the nonmedicated rats. These data suggest that GTC have a protective effect on the pathogenesis of cerulein pancreatitis.

The effect of epidermal growth factor on the septic complications of acute pancreatitis

Bacterial translocation (BT) from the gastrointestinal tract to mesenteric lymph nodes (MLN) and other extraintestinal organs is an important source of infection in acute pancreatitis (AP). Epidermal growth factor (EGF), a peptide hormone with trophic effects on gut mucosa, has decreased intestinal mucosal injury in septic rats and decreased burn-induced BT in mice. The purpose of this study is to examine whether EGF could affect BT in acute necrotizing pancreatitis. Forty-eight male Sprague-Dawley rats (250-350 g) were studied. AP was induced in Group I and Group II by pressure injection of 3% taurocholate and trypsin into the biliopancreatic duct (1 ml/kg of body weight). Group III and Group IV underwent laparotomy without induction of acute pancreatitis. Group I rats received human recombinant EGF (100 micrograms/kg, subcutaneously twice daily) and Group II rats received a similar volume of 0.1% bovine serum albumin as a placebo postoperatively. Group III and Group IV received EGF and placebo, respectively. At 48 hr postoperatively, blood was drawn for culture and amylase determinations. Jejunum and ileum were obtained to measure mucosal protein content, mucosal thickness, villus height, and crypt depth. Specimens from MLN, spleen, liver, pancreas, and cecum were harvested for pathology and culture of gram positive (G+), gram negative (G-), and anaerobic bacteria. Ileal mucosal protein levels were increased significantly in Group I (1.96 +/- 0.14 mg/cm) compared to Group II (0.95 +/- 0.15 mg/cm intestinal segment) (P < 0.01). Jejunal and ileal mucosal thickness, villus height, and crypt depth in Group I were significantly increased when compared to Group II (P < 0.05). All 12 rats in Group II had BT to MLN compared to 58% (7 of 12 rats) in Group I (P < 0.05). Thirty-three percent (4 of 12 rats) had BT to distant sites such as pancreas, spleen, liver, and/or blood in Group I vs 83% (10 of 12 rats) in Group II (P < 0.05). EGF treatment minimizes intestinal damage, decreases BT to MLN and bacterial spread to distant sites, and may be beneficial in preventing septic complications in AP.

Pathological changes in pancreatic ducts from patients with chronic pancreatitis

CONCLUSION

Chronic pancreatitis and restricted pancreatic outflow are accompanied by pathological changes in the ducts, including inflammation and alterations in the microvasculature. These changes and loss of epithelium provide a likely explanation for increased release of serum proteins, immunoglobulins, and lactoferrin into the juice, and the possibility of luminal contents entering the extracellular space and bloodstream.

BACKGROUND

Enlargement of pancreatic ducts is a well-known phenomenon accompanying chronic pancreatitis and conditions restricting outflow of pancreatic juice. However, the relationship between ductal pathology and concomitant changes in the pancreatic juice is incompletely understood.

METHODS

Segments of pancreatic ducts removed at surgery from patients with chronic pancreatitis and conditions restricting outflow were studied by light and electron microscopy to assess the pathological changes.

RESULTS

Pathological changes in ducts from patients with chronic pancreatitis include chronic inflammation in the wall, enlarged and numerous capillaries packed with erythrocytes and leukocytes close to the lumen, and loss of epithelium and sometimes basement membrane. Plasma cells provide a source for increased immunoglobulins. Ducts from patients with diseases restricting outflow show significant pathology.

Expression of heat shock proteins in chronic pancreatitis: protective or pathogenic roles?

The tissue-distributions of heat shock proteins (HSP) identified by monoclonal antibodies ML-30, TB-78, CA-Str7-1, and MAB 72/73 have been examined in formalin-fixed and paraffin wax-embedded tissues from 10 normal pancreatic specimens and 92 cases of chronic pancreatitis. The chronic pancreatitis cases were divided by probable etiology into alcohol-related, postacute pancreatitis, or idiopathic. The HSP identified by ML-30 and CA-Str7-1 were constitutively expressed, with a regional distribution, by duct and ductular epithelial cells in all normal pancreatic tissues. The HSP detected by ML-30 were expressed uniformly throughout the cytoplasm of the majority of ductular epithelial cells in all cases of chronic pancreatitis, irrespective of suspected etiology, and in the ducts of all but two cases of alcohol-associated chronic pancreatitis. The HSP defined by CA-Str7-1 were identified in the majority of duct or ductular epithelial cells in most of the cases of chronic pancreatitis, although possible differential expression was observed with respect to etiology (ie, there seemed to be less HSP in cases of postalcohol pancreatitis). The HSP identified by TB-78 were not constitutively expressed by normal pancreatic tissues but were found in a few scattered epithelial cells in two of these cases. However, significant expression of these HSP were observed in most epithelial cells in a population of cases regarded as either alcohol-associated (0.05 > p > 0.02) or postacute chronic pancreatitis (0.01 > p > 0.001). The HSP identified by monoclonal antibody MAB 72/73 were either not demonstrable or were expressed at very low levels in both the normal and inflamed pancreatic tissues. Expression of the four groups of HSP molecules appeared to be differentially regulated both in normal pancreatic and in chronic pancreatitis tissues. These differences in expression may indicate different functions in normal tissues, with either a protective or a pathogenic role for these proteins in the diseased state. Our current findings support the hypothesis that expression of certain HSP, particularly those identified by TB-78, may be involved in the pathogenesis of distinct subtypes of chronic pancreatitis. Our data do not suggest that HSP are the primary targets of immune-mediated cytotoxic activity; nevertheless, enhanced expression of these molecules by pancreatic ductular epithelial cells does provide an environment in which increased amounts of endogenous intracellular peptides may be transported to the cell surface, thereby becoming potential targets of immune-surveillance and cell-mediated cytotoxicity. Conversely, HSP may play a protective role in such a manner that selected groups of pancreatic ductular epithelial cells withstand cytotoxic damage of chemical, metabolic, or immune origin, and for significantly increased periods of time than they would otherwise; HSP thereby conserve a population of "reserve" epithelial cells from which pancreatic regeneration might occur. Identification of distinct pathogenic groups, defined according to precise immunohistochemical criteria, might provide the basis of a functional assessment and hence allow development of biologically appropriate strategies for managing individual patients with chronic pancreatitis.

Combined treatment with C1 esterase inhibitor and antithrombin III improves survival in severe acute experimental pancreatitis

BACKGROUND

Patients with severe acute pancreatitis die of complications closely related to the systemic activation of protease cascades.

AIM

To examine the effects of human C1 esterase inhibitor (C1 INH) and antithrombin III (AT III) on two experimental models of acute pancreatitis.

METHODS

Oedematous pancreatitis was induced by continuous intravenous infusion of caerulein and haemorrhagic pancreatitis by retrograde injection of sodium taurocholate into the biliopancreatic duct. C1 INH and AT III were given intravenously, either before or after the induction of pancreatitis. Treatment with C1 INH and AT III had no beneficial effect on oedematous pancreatitis. On the other hand, combined C1 INH and AT III therapy improved the survival in haemorrhagic pancreatitis compared with treatment with human serum albumin. This reduction in mortality was found regardless of whether the treatment was given prophylactically or therapeutically.

CONCLUSIONS

Treatment with C1 INH and AT III represents a promising therapeutic concept for patients with severe haemorrhagic pancreatitis.

Ethanol consumption and susceptibility of the pancreas to cerulein-induced pancreatitis

Despite the fact that alcoholism is one of the major causes of pancreatitis, the pathogenesis of this disorder remains obscure. Factors such as the pattern of ethanol consumption, diet, and genetic predisposition may be contributing factors. The failure to produce alcoholic pancreatitis in experimental animals suggests that experimental provision of ethanol may only increase the predisposition to pancreatitis. To test this possibility, we developed an assay system using the in vitro model of cerulein-induced pancreatitis. In this system, pancreatic lobules were first exposed to a supraphysiologic concentration (10(-6) M) of the cholecystokinin analogue, cerulein, after which homogenates were incubated for up to 6 h. Activation of trypsinogen and chymotrypsinogen was observed only in cerulein-treated preparations. We then investigated the effects of the duration of ethanol feeding on cerulein-induced changes in rat pancreas. The pancreata from rats fed ethanol for 9-12 months were more susceptible to cerulein-induced activation of chymotrypsinogen compared to the pancreata from pair-fed control animals. This susceptibility also paralleled morphologic changes, such as dilatation of endoplasmic reticulum, only in the ethanol-fed group. In contrast, during the early stages (up to 3 months) of ethanol consumption, there was resistance (p < 0.01) to cerulein-induced changes. These results suggest that long-term ethanol consumption increases susceptibility to pancreatitis and raises the possibility that a similar mechanism may operate in human alcoholics.

Interleukin 10 reduces the severity of acute pancreatitis in rats

BACKGROUND & AIMS

Previous studies have documented the effectiveness of interleukin (IL)-10 if given before the onset of experimental acute pancreatitis. This study examined whether IL-10, a cytokine that inhibits macrophage release of inflammatory mediators, would alter the severity of acute pancreatitis if given before or after the induction of disease.

METHODS

Eighty-four Sprague-Dawley rats were divided into four groups. Group 1 received intravenous saline, and groups 2, 3, and 4 received intravenous cerulein (8.5 microg x kg(-1) x h(-1)). Group 3 was also given 150,000 U of intraperitoneal IL-10 1 hour before cerulein infusion and every 3 hours thereafter. Group 4 received 150,000 U intraperitoneal IL-10 2 hours after cerulein infusion and every 3 hours thereafter. Serum amylase and tumor necrosis factor (TNF)-alpha levels were measured before and 3, 9, or 15 hours after induction of pancreatitis. Animals were killed at these time points. Pancreata were analyzed for edema and TNF-alpha mRNA and TNF-alpha protein concentrations and were graded histologically.

RESULTS

Serum amylase, TNF-alpha mRNA, and TNF-alpha protein levels, pancreatic edema, and histological score were significantly reduced when IL-10 was administered either before or after induction of pancreatitis. Serum TNF-alpha levels were undetectable.

CONCLUSIONS

IL-10 attenuated the severity of experimental acute pancreatitis if given either before or after the induction of the disease. These results are consistent with the hypothesis that the macrophage is important in determining the severity of acute pancreatitis in this model.

Role of endogenous cholecystokinin and cholecystokinin-A receptors in the development of acute pancreatitis in rats

Recent studies provide significant evidence that cholecystokinin (CCK) is involved in the induction and development of acute pancreatitis in experimental animals. However, the results obtained with specific CCK-A (peripheral) receptor antagonists are still controversial. The present studies were undertaken to evaluate the involvement of endogenous CCK and the CCK-A receptors in the development of severe acute pancreatitis induced in Otsuka Long-Evans Tokushima Fatty (OLETF) rats that have a selective defect in the CCK-A receptor. Three models of severe acute pancreatitis were induced by retrograde intraductal infusion of 4% sodium taurocholate, by the closed duodenal loop, or by a single intraperitoneal injection of 500 mg/100 g body weight of L-arginine in OLETF rats and control Long-Evans Tokushima Otsuka (LETO) rats. Plasma CCK levels rose up to 4- to 14-fold over the preloading values after the onset of acute pancreatitis in all three models in both groups of rats. However, histologic alterations as well as the magnitudes of increase in serum amylase and lipase activity and the pancreatic wet weight were significantly less in the OLETF rats than those in the LETO rats. In addition, 72 h after the onset of arginine pancreatitis, massive destruction of pancreatic parenchyma with a significant reduction in serum amylase and lipase activities and pancreatic wet weight was observed in the LETO rats, whereas these changes were not seen in OLETF rats. These results suggest that endogenous CCK and CCK-A receptors play a role in the development of severe acute pancreatitis in rats.

Avian influenza A virus induced stunting syndrome-like disease in chicks

Two-day-old specific-pathogen free chicks were inoculated with type A influenza virus (A/whistling swan/Shimane/499/83 (H5N3) through the air sac. Inoculated chicks showed mild to severe diarrhea and lesions of pancreatitis and atrophy of the pancreas, thymus and bursa of Fabricius. One chick died on each of days 4, 6 and 14 postinoculation (PI). Reduced weight gain was conspicuous from day 22 PI. Positive immunoreaction to the virus antigen was detected in the pancreas, kidneys, liver, lungs and air sacs, and cecal lamina propria. Virus recovery persisted longer in the pancreas. Some of these findings conformed to those of stunting syndrome.

Pathophysiological role of secretory type I and II phospholipase A2 in acute pancreatitis: an experimental study in rats

BACKGROUND

In human acute pancreatitis two different types of secretory phospholipase A2 (PLA2) have been found.

AIM

To analyse the specific pattern of distribution of these PLA2 activities and their pathophysiological role in experimental acute pancreatitis.

SUBJECTS AND METHODS

Catalytic activities of secretory type I (pancreatic) and type II (non-pancreatic) PLA2 and the protein concentration of immunoreactive pancreatic PLA2 (IR-PLA2) in serum and pancreatic tissue of rats with cerulein (mild form) and sodium taurocholate (severe form) induced acute pancreatitis were determined.

RESULTS

Cerulein infusion caused a significant increase in type I PLA2 activity (p < 0.01) and IR-PLA2 protein concentration (p < 0.01) in serum and pancreas, whereas type II PLA2 activity remained unchanged during the 12 hour observation period. Histology showed no significant tissue destruction. In sodium taurocholate induced acute pancreatitis type II PLA2 activity significantly increased, reaching values over 10-fold higher than controls (p < 0.01), whereas IR-PLA2 protein concentration and type I PLA2 activity were only marginally increased. In this severe model of acute pancreatitis significantly lower values were detected than in the control pancreas (p < 0.002) for PLA2 activity and IR-PLA2 protein concentration. Histology showed parenchymal and fat necroses with haemorrhage, oedema, and inflammatory cell infiltration.

CONCLUSIONS

Type I PLA2 activity is dependent on the IR-PLA2 protein concentration in serum and pancreatic tissue. The type II PLA2 activity is not stimulated by cerulein, which indicates an extra-acinar origin of this enzyme. Type II PLA2 activity is significantly increased in sodium taurocholate induced acute pancreatitis indicating its role in the local necrotising process and involvement in the systemic effects in severe acute pancreatitis.

Expression of transforming growth factor-beta 1 and epidermal growth factor in caerulein-induced pancreatitis in rat

Growth factors such as TGF-beta 1 and EGF are known to modulate the deposition of extracellular matrix components and tissue repair and to affect the cellular growth but their expression in the course of pancreatitis has not been studied. In this study we investigated the gene expression of TGF-beta 1 mRNA and EGF mRNA and other parameters of the pancreas including DNA synthesis, blood flow (PBF), tissue protein content and plasma amylase during the induction of acute pancreatitis. Supramaximal dose of cearulein (10 mg/kg/h s.c.) was infused for 5 h to induce pancreatitis. Animals were killed after 1, 2, 3, 4 and 5 h of infusion. The PBF was measured, blood samples were withdrawn to determine serum amylase concentration, biopsy samples were taken to measure the protein content and DNA synthesis. Expression of TGF-beta 1 and EGF mRNA was studied by reverse-transcription of polymerase chain reaction (RT-PCR). Caerulein infused caused a time-dependent decrease in DNA synthesis accompanied by gradual decrease of PBF and significant increase in pancreatic weight. The pancreatic protein content and plasma amylase showed progressive rise during 5 h of cearulein infusion. Histology revealed tissue edema, cellular vacuolization and prominent leukocyte infiltration after 3 h of cearulein infusion. TGF-beta 1 mRNA was strongly expressed at each time interval beginning from the 1 h after the start of cearulein infusion. In contrast, EGF mRNA was detected only at 5 h after induction of pancreatitis. We conclude that 1) the development of caerulein-induced pancreatitis results in the inhibition of pancreatic growth and the reduction in PBF accompanied by enhanced expression of TGF-beta 1; 2) The expression of EGF that was observed at the end of the induction of pancreatitis may indicate the initiation of pancreatic repair; 3) TGF-beta 1 seems to lead to subsequent induction of EGF that may stimulate the regeneration of injured pancreas.

The pancreatitis-associated protein I promoter allows targeting to the pancreas of a foreign gene, whose expression is up-regulated during pancreatic inflammation

The pancreatitis-associated protein I (PAP I) is a pancreatic secretory protein expressed in pancreas during acute pancreatitis but not in the healthy pancreas. The promoter of the PAP I gene thus represents a potential candidate to drive expression of therapeutic molecules to the diseased pancreas. In this work, we have constructed recombinant adenoviruses harboring the chloramphenicol acetyltransferase (CAT) gene driven by several fragments of the PAP I promoter and have characterized their properties in vitro and in vivo. In vitro studies showed that the transduction of the pancreatic cell line AR-42J with these adenoviruses led to low levels of CAT activity in basal conditions. After stimulation with a combination of interleukin-6 and dexamethasone or after induction of oxidative stress, CAT activity was strongly induced, a characteristic of the endogenous PAP I gene. Stimulation was maximal when constructs comprised 1253 base pairs of the PAP I promoter, upstream from initiation of transcription, and decreased with shorter fragments of 317, 180, 118 or 61 base pairs. The recombinant adenovirus containing the CAT gene under the control of the PAP I promoter fragment (-1253/+10) was also tested in vivo. Following administration by intravenous injection into mice, CAT activity was measured in several tissues 96 h later. In healthy animals, low but significant CAT activity was detected in pancreas, compared with near background values observed in the other tissues. When experimental acute pancreatitis was induced, CAT expression was strongly enhanced only in pancreas. In control experiments with adenoviruses in which the CAT gene was driven by the cytomegalovirus promoter, higher levels of expression were observed in all tissues. Expression was not modified after induction of acute pancreatitis. In conclusion, this study shows that (i) a recombinant adenovirus containing a fragment of the PAP I promoter allows specific targeting of a reporter gene to the mouse pancreas and (ii) expression of the reporter gene in pancreas is induced during acute pancreatitis. Adenovirus-mediated gene therapy of acute pancreatitis is therefore conceivable.

[Acute pancreatitis in Caroli's syndrome]

Caroli's syndrome is included in the fibropolycystic abnormalities of the bile ducts. The disease is usually manifested by episodes of cholangitis. We report a case which presented as acute pancreatitis in the adulthood. The diagnosis was obtained by ultrasonography, CT scan, ERCP and liver biopsy. A choledochojejunostomy was performed with poor outcome and the patient is in the waiting list for liver transplantation.

Etiologic links between chronic pancreatitis and pancreatic cancer

In all forms of pancreatitis there appears to be a cellular dysfunction, glandular destruction, and, presumably, increased cell turnover. Increased cell division has been suggested as a potential precursor of cancer in many organs. The excess risk of pancreatic cancer that has been documented in epidemiologic studies in patients with various types of pancreatitis is consistent with this hypothesis. The uncertainties in epidemiologic studies notwithstanding, the existence of a clear association between pancreatitis and the subsequent risk of pancreatic cancer is found too often to be only randomized. The clinical relevance of a causal relationship between chronic pancreatitis and pancreatic cancer is, however, limited, since the prognosis of chronic pancreatitis cannot be separated from that of chronic alcoholism.

Acute pancreatitis in rats: effects of sodium taurocholate, CCK-8, and Sec on pancreatic microcirculation

With use of in vivo microscopy, pancreatic duct permeability, red blood cell (RBC) velocities, functional capillary density (FCD), and overall changes in capillary blood flow (perfusion index) were estimated after intraductal infusion of sodium taurocholate (0.8 ml, 4%) alone or in combination with systemic administration of cholecystokinin (CCK, 0.3 microg/100 g body wt) or secretin (Sec, 10 microg/100 g body wt). Sodium taurocholate mediated a significant increase in pancreatic duct and capillary permeability within 105 +/- 26 s followed by a transient decrease in RBC velocities and a sustained decrease in FCD, which were paralleled by dramatic flow heterogeneity. Therefore, a significant reduction in overall capillary blood flow was calculated. CCK stimulation aggravated the microcirculatory failure due to a decrease in RBC velocities, which was accompanied by an increase in acinar cellular necrosis. Sec stimulation attenuated microcirculatory failure due to a more moderate reduction of FCD. The enhanced pancreatic duct and capillary permeability, which enables free diffusion of pancreatic digestive enzymes into the parenchyma, is the initiating event in acute biliary pancreatitis, causing microcirculatory failure and tissue damage. The microcirculatory changes are secondary and a propagating factor for the development of acini necrosis. Stimulation with CCK worsened the course of acute biliary pancreatitis.