Ligation-induced Acute Pancreatitis Research Articles

The Novel Cytokine Interleukin-33 Activates Acinar Cell Proinflammatory Pathways and Induces Acute Pancreatic Inflammation in Mice

BackgroundAcute pancreatitis is potentially fatal but treatment options are limited as disease pathogenesis is poorly understood. IL-33, a novel IL-1 cytokine family member, plays a role in various inflammatory conditions but its role in acute pancreatitis is not well understood. Specifically, whether pancreatic acinar cells produce IL-33 when stressed or respond to IL-33 stimulation, and whether IL-33 exacerbates acute pancreatic inflammation is unknown.Methods/ResultsIn duct ligation-induced acute pancreatitis in mice and rats, we found that (a) IL-33 concentration was increased in the pancreas; (b) mast cells, which secrete and also respond to IL-33, showed degranulation in the pancreas and lung; (c) plasma histamine and pancreatic substance P concentrations were increased; and (d) pancreatic and pulmonary proinflammatory cytokine concentrations were increased. In isolated mouse pancreatic acinar cells, TNF-α stimulation increased IL-33 release while IL-33 stimulation increased proinflammatory cytokine release, both involving the ERK MAP kinase pathway; the flavonoid luteolin inhibited IL-33-stimulated IL-6 and CCL2/MCP-1 release. In mice without duct ligation, exogenous IL-33 administration induced pancreatic inflammation without mast cell degranulation or jejunal inflammation; pancreatic changes included multifocal edema and perivascular infiltration by neutrophils and some macrophages. ERK MAP kinase (but not p38 or JNK) and NF-kB subunit p65 were activated in the pancreas of mice receiving exogenous IL-33, and acinar cells isolated from the pancreas of these mice showed increased spontaneous cytokine release (IL-6, CXCL2/MIP-2α). Also, IL-33 activated ERK in human pancreatic tissue.SignificanceAs exogenous IL-33 does not induce jejunal inflammation in the same mice in which it induces pancreatic inflammation, we have discovered a potential role for an IL-33/acinar cell axis in the recruitment of neutrophils and macrophages and the exacerbation of acute pancreatic inflammation.ConclusionIL-33 is induced in acute pancreatitis, activates acinar cell proinflammatory pathways and exacerbates acute pancreatic inflammation.

Systemic Inflammation with Multiorgan Dysfunction Is the Cause of Death in Murine Ligation-Induced Acute Pancreatitis

BackgroundWe have previously shown that distal pancreatic duct ligation-induced acute pancreatitis in mice is associated with substantial mortality. MethodsWe examined the cause of death in duct ligation-induced acute pancreatitis in mice by serial examination of multiple parameters in three experimental groups: distal pancreatic duct ligation (PD), bile duct ligation alone (BD), and sham operation (S). ResultsBD and S had no mortality, while PD had 94% mortality with most deaths between days 2 and 4. Characteristics of mice with acute pancreatitis included (ANOVA; p < 0.05): extracellular regulated kinase activation in the pancreas and lung; pancreatic neutrophil infiltration and acinar cell necrosis maximal on day 2; increased plasma cytokine and aspartate aminotransferase levels and bronchoalveolar lavage fluid neutrophil count and cytokine levels, peaked on day 3; hypotension and bradycardia were worst on day 4; pulmonary neutrophil infiltration and plasma creatinine level peaked on day 4. Liver injury evidenced by raised aspartate serum transaminase after hepatic obstruction was exacerbated by PD. ConclusionsSystemic inflammation with multiorgan dysfunction causes death in pancreatic duct ligation-induced acute pancreatitis in mice. This experimental model is a suitable experimental analogy of “early severe gallstone pancreatitis” to investigate disease pathogenesis and to evaluate novel therapeutic strategies.

Mast Cell Activation and Interleukin-33 Upregulation in Pancreas and Lung of Pancreatic Duct Ligation-Induced Acute Pancreatitis in Rodents

Mast Cell Activation and Interleukin-33 Upregulation in Pancreas and Lung of Pancreatic Duct Ligation-Induced Acute Pancreatitis in Rodents

Systemic Inflammation With Multiorgan Dysfunction is the Cause of Death in Murine Pancreatic Duct Ligation-Induced Acute Pancreatitis

Systemic Inflammation With Multiorgan Dysfunction is the Cause of Death in Murine Pancreatic Duct Ligation-Induced Acute Pancreatitis

Enhanced interleukin-33 expression and mast cell activation in pancreas and lung tissues of pancreatic duct ligation-induced acute pancreatitis in rodents (117.16)

Abstract IL-33 is a newly identified member of the IL-1 cytokine family mainly expressed by epithelial cells, endothelial cells, fibroblasts, macrophages and mast cells. IL-33 release is known to increase in tissues of inflammation and is a potent activator of immune cells including mast cells. Elevation of IL-1β and TNF-α in acute pancreatitis has been already reported, and these cytokines upregulate IL-33 expression in inflammation. Activation of mast cells leads to the release of preformed mediators (eg., histamine) and proinflammatory cytokines (eg., IL-1β, TNF-α) and chemokines. Here we investigated mast cell activation and IL-33 expression following 5-48 hr of distal pancreatic duct ligation (PD)-induced acute pancreatitis in rats and mice. PD showed mast cell degranulation in the pancreas and lung, compared to sham controls. Rat plasma showed increased histamine levels with 48 hr of PD than sham controls. Immunohistochemistry, ELISA and immunoblotting results showed increased IL-33 expression in the rat and mouse exocrine pancreas and lung with 5-48 hr of PD. Murine bronchoalveolar lavage fluid showed higher IL-33 level in 48 hr of PD. Mast cell derived mediators and enhanced IL-33 expression may contribute to the progression of pancreatic and pulmonary inflammation. These results will enhance our understanding of acute pancreatitis pathogenesis and could indicate new therapeutic targets.

Murine pancreatic duct ligation induces stress kinase activation, acute pancreatitis, and acute lung injury

Background Acute lung injury is a major determinant of outcomes in acute pancreatitis. We evaluated acute lung injury and stress kinase activation in ligation-induced acute pancreatitis in mice. Methods Mice with duct ligation or sham operation were killed after 24 or 48 hours. Results In addition to acute pancreatitis, duct ligation was associated with pulmonary morphologic changes indicative of acute lung injury (alveolar septal thickening, congestion, and neutrophil infiltration). Furthermore, immunoblotting showed stress kinase activation in the pancreas and lung after ligation. Although mortality was observed in the ligated group, that is consistent with severe lung injury, it requires further evaluation. Conclusions Bile and pancreatic duct ligation in the mouse is associated with pancreatic and pulmonary stress kinase activation and acute inflammatory changes consistent with early acute pancreatitis and acute lung injury. Our findings are important as acute lung injury increases mortality in clinical acute pancreatitis and stress kinases are established proinflammatory signal transducers.

Enteral Exclusion Increases Map Kinase Activation and Cytokine Production in a Model of Gallstone Pancreatitis

Background: We have previously demonstrated that enteral exclusion augments pancreatic p38 mitogen-activated protein (MAP) kinase activation and tumor necrosis factor-α (TNF-α) production after bile-pancreatic duct ligation in rats. Methods: In the present study, we evaluated c-Jun NH2-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) activation, and cytokine production, in pancreata of duct-ligated rats with and without duodenal bile-pancreatic juice replacement from a donor rat. We hypothesized that enteral exclusion of bile-pancreatic juice activates stress kinases and induces cytokine production in ligation-induced acute pancreatitis. Results: Increased JNKand ERKactivation after ligation are inhibited by bile-pancreatic juice replacement. Increases in pancreatic production of IL-1β and IL-12 after ligation are significantly subdued by replacement. In additional in vitro studies, we show that cholecystokinin- or TNF-α-stimulated nuclear transcription factor kappa-B activation in AR42J cells is inhibited by dominant negative ERK2.

Bile and pancreatic juice exclusion activates acinar stress kinases and exacerbates gallstone pancreatitis

Bile and pancreatic juice exclusion from gut activates acinar stress kinases and exacerbates gallstone pancreatitis as evidenced by the ameliorating effects of replacement therapy in an experimental model of duct ligation-induced acute pancreatitis. In the early stages of gallstone pancreatitis, bile-pancreatic juice cannot enter the gut. Enteral exclusion worsens pancreatitis by causing feedback hyperstimulation of the exocrine pancreas that activates acinar cell stress kinases. Investigations using a unique surgical model, the Donor Rat Model, showed that duodenal replacement of bile-pancreatic juice in rats with duct ligation attenuates pancreatic stress kinase activation, reduces pancreatic cytokine production, and ameliorates pancreatic morphologic changes. These findings suggest that exclusion-induced acinar hyperstimulation, in the presence of duct obstruction, exacerbates acute pancreatitis via stress kinase activation. Although acinar hyperstimulation has often been implicated in the pathogenesis of acute pancreatitis, the lack of supporting evidence remains a conspicuous void. The proposed hypothesis draws on fresh evidence to present a new paradigm that reexamines the role of exocrine pancreatic hyperstimulation in gallstone pancreatitis pathogenesis.

Morphologic characterization of early ligation–induced acute pancreatitis in rats

Background Bile-pancreatic duct ligation in rats causes acute pancreatic inflammation. We performed serial morphologic evaluation of the exocrine pancreas after duct ligation to facilitate further investigations using the model. Methods The pancreas was excised from 74 rats after 0, 1, 3, 5, 24 or 48 hours of duct ligation or sham surgery. A pathologist evaluated 1 hematoxylin- and eosin-stained slide from each rat. Confirmatory immunostaining was performed with markers for apoptosis (activated caspase-3), proliferation (cyclin D3), neutrophils (myeloperoxidase), and macrophages (CD68). Results Interstitial edema and white blood cell infiltration were apparent at 24 hours and increased at 48 hours. Progressive periods of duct ligation were characterized by ductular ectasia (1 to 3 hours), acinar vacuolization (5 to 48 hours), leukocytic margination and neutrophil exocytosis (5 to 48 hours), ductule epithelium hypertrophy and proliferation (24 to 48 hours), and discernible loss of zymogen granules (48 hours). Conclusions Ligation-induced acute pancreatitis in rats is a useful model to investigate early events in disease pathogenesis.

Bile-Pancreatic Juice Exclusion Promotes Akt/NF-κB Activation and Chemokine Production in Ligation-Induced Acute Pancreatitis

Using a unique surgical model (the donor rat model), we showed previously that duodenal replacement of bile-pancreatic juice, obtained fresh from a donor rat, ameliorates ligation-induced acute pancreatitis. We hypothesize that bile-pancreatic juice exclusion from gut exacerbates Akt/nuclear factor-kappaB (NF-kappaB) pathway activation and induces chemokine production in ligation-induced acute pancreatitis. We compared rats with bile-pancreatic duct ligation to those with duodenal bile-pancreatic juice replacement fresh from a donor rat beginning immediately before duct ligation. Sham control rats had ducts dissected but not ligated. Rats were killed 1 or 3 hours after operation (n = 7/group). Akt activation (immunoblotting, immune-complex kinase assay, and ELISA), inhibitory protein I-kappaB (IkappaB) activation (immunoblotting), and production of chemokines MCP-1 and RANTES (ELISA) were measured in pancreatic homogenates. NF-kappaB was quantitated in nuclear fractions using electrophoretic mobility shift assay. Duct ligation produced significant increases in pancreatic Akt, IkappaB, and NF-kappaB activation and production of MCP-1 and RANTES. Activation of the Akt/NF-kappaB pathway and increased MCP-1 and RANTES production in response to duct ligation were significantly reduced by bile-pancreatic juice replacement (ANOVA, P < 0.05). Bile-pancreatic juice exclusion stimulates Akt/NF-kappaB pathway activation and increases chemokine production in ligation-induced acute pancreatitis.

DUCT OBSTRUCTION AND BILE-PANCREATIC JUICE (BPJ) EXCLUSION ARE REQUIRED FOR MAXIMUM PANCREATIC INFLAMMATORY MEDIATOR PRODUCTION IN LIGATION-INDUCED ACUTE PANCREATITIS IN RATS

Bile-pancreatic duct ligation obstructs the duct, excludes BPJ from gut, and induces acute pancreatitis. Using our unique Donor Rat Model, we previously showed that combined duct obstruction and BPJ exclusion is associated with the most severe pancreatic morphologic changes and hypercholecystokininemia when compared to duct obstruction alone or BPJ exclusion alone. Here, we test the hypothesis that combined Obstruction + Exclusion (OE) is associated with greater production of pancreatic inflammatory mediators than either Obstruction alone (O) or Exclusion alone (E). Sham controls had duct dissection only (S). We measured pancreatic production of cytokines (IL-1, IL-12) and chemokines (MCP-1, RANTES) at the 1- and 3-hr time points using ELISA. P < 0.05; ANOVA, n = 6-7 rats/groups. Compared to Sham, OE was associated with marked increases in pancreatic cytokine (IL-1, IL-12) and chemokine (MCP-1, RANTES) production that were significantly ameliorated by enteral BPJ replacement (O vs OE). Although E alone was associated with inflammatory mediator production that was mildly greater than Sham (E vs S), the increase was still significantly below that of rats with duct ligation (E vs OE). In summary, pancreatic cytokine production and chemokine production are markedly greater with combined Obstruction + Exclusion than either Obstruction alone or Exclusion alone (OE vs O or E). These findings indicate that both duct obstruction and BPJ exclusion are essential for the maximum production of acute inflammatory mediators in the pancreas in ligation-induced acute pancreatitis. Our results support our central hypothesis that BPJ exclusion from gut plays an important role in the mechanism of disease pathogenesis. (Support: American College of Surgeons Faculty Research Fellowship 2003-2005; NIH K08 Career Development Award #K08-DK062805)

Bile-pancreatic juice exclusion increases cholinergic M3 and CCK-A receptor expression and interleukin-6 production in ligation-induced acute pancreatitis

Background Using an original model, the Donor Rat Model, we showed that bile-pancreatic juice (BPJ) exclusion from gut exacerbates ligation-induced acute pancreatitis in rats. We also showed that muscarinic cholinergic M3 and CCK-A receptor expression is induced following duct ligation. Increased receptor number potentially could exacerbate cytokine production. We hypothesize that BPJ exclusion is responsible for M3 and CCK-A receptor induction and increased interleukin-6 (IL-6) production. Methods M3 and CCK-A receptor expression and IL-6 production were compared in rat pancreata 1 to 3 hours after duct ligation with or without BPJ replacement. Results Our studies showed that BPJ replacement attenuates duct ligation–induced increases in M3 and CCK-A receptor expression and IL-6 production. Conclusions In this model, BPJ exclusion from gut induces M3 and CCK-A receptor expression and increases IL-6 production. In this experimental corollary of gallstone pancreatitis, BPJ exclusion from gut may play a key role in the mechanism of disease pathogenesis.

GLIA MATURATION FACTOR (GMF) REGULATES PANCREATIC ACINAR CELL CYTOKINE PRODUCTION AND CELL SURVIVAL.

GMF is a highly conserved brain protein that modulates cytokine production and cell survival in certain cells. We have shown that GMF is induced in the pancreas in duct ligation-induced acute pancreatitis in rats. We hypothesize that GMF regulates acinar cell cytokine production and cell survival. Using primary cultures of pancreatic fragments, cytokine production was quantitated by ELISA, and susceptibility to cell death in response to H2O2 was evaluated by MTT assay. We overexpressed GMF in rat pancreatic fragments using a replication-defective adenovirus vector containing GMF cDNA. A cytoplasmic lacZ (β-galactosidase) expressing adenoviral construct was used as control. Pancreatic fragments infected with the GMF-adenovirus showed 12-fold and 16-fold increases in TNF and IL-1 production, respectively*. Incubation of pancreatic fragments with specific GMF neutralizing antibody prior to ad-eno-GMF virus infection inhibited TNF and IL-1 production by 80%*. GMF over-expression was also associated with a doubling in susceptibility to cell death. We then incubated pancreatic fragments from GMF+/+ and GMF−/ −mice with saline or 100nM cerulein. Cerulein stimulation significantly* increased TNF (259±3 vs 69±1) and IL-1 (294±11 vs 63±1) in GMF+/+ pancreatic fragments, whereas in GMF−/ − pancreatic fragments the increase in TNF (69±5 vs 37±1) and IL-1 (59±0.3 vs 27±2) was markedly limited#. Furthermore, cerulein-stimulated TNF and IL-1 production by GMF−/ − pancreatic fragments was impressively increased by reconstituting GMF in fragments with adeno-GMF infection. Acinar cell viability was near-100% in the GMF−/ −group but only 65% in the GMF+/+ group*. In all experiments, GMF expression was evaluated by immunoblotting. GMF−/ − fragments did not express GMF even with cerulein stimulation. Conclusions: 1) Overexpression of GMF in pancreatic acinar cells increases TNF and IL-1 production and susceptibility to cell death. 2) Downregulation of GMF markedly diminishes cerulein-stimulated acinar cell TNF and IL-1 production and improves cell survival. These findings suggest that GMF plays a key role in regulating acute pancreatic inflammation and acinar cell survival. Therefore, GMF may play a crucial role in acute pancreatitis pathogenesis. (*ANOVA, p<0.001; #pg/ml)).

Bile-pancreatic juice (BPJ) exclusion exacerbates Akt/NF-kB pathway activation and increases chemokine production in ligation-induced acute pancreatitis

Abstract Introduction: Using a unique surgical model (The Donor Rat Model) we showed that duodenal replacement of BPJ, obtained fresh from a Donor Rat, ameliorates pancreatic morphologic changes, hyperamylasemia and hypercholecystokininemia in ligation-induced acute pancreatitis. We hypothesize that BPJ exclusion from gut exacerbates Akt/NF-kB pathway activation and induces proinflammatory chemokine production in ligation-induced acute pancreatitis. The cytosolic IkB/NF-kB complex dissociates when IkB is phosphorylated following Akt activation, allowing NF-kB to translocate to the nucleus and induce transcription of various inflammatory mediators including chemokines. Methods: We studied rats as follows: Diseased-controls had bile-pancreatic duct ligation. Diseased-treated rats had duodenal BPJ replacement fresh from a Donor Rat beginning immediately before duct ligation. Sham controls had ducts dissected only. Rats were killed after 1 or 3 hours (n = 7/group). Pancreatic homogenates were used to determine Akt activation (immunoblotting, immunecomplex kinase assay and ELISA), IkB activation (immunoblotting), and production of chemokines MCP-1 and RANTES (ELISA). NF-kB was quantitated in pancreatic nuclear fractions using EMSA. Results: Compared to sham, duct ligation was associated with marked increases in pancreatic Akt and IkB activation, NF-kB nuclear translocation, and MCP-1 and RANTES production. Akt/NF-kB pathway activation and increased MCP-1 and RANTES production after duct ligation were substantially ameliorated by BPJ replacement (ANOVA, p Conclusions: BPJ exclusion from gut exacerbates Akt/NF-kB pathway activation and increases chemokine production in ligation-induced acute pancreatitis. These findings support our central hypothesis that BPJ exclusion-induced acinar cell hyperstimulation exacerbates acute pancreatic inflammation in this experimental corollary of gallstone-induced acute pancreatitis. (Support: ACS Faculty Research Fellowship, NIH-K08 Award#DK062805)

Cholinergic receptor induction and JNK activation in acute pancreatitis

Background Cholecystokinin-A (CCK-A) and cholinergic receptor pathways, capable of activating stress kinases p38 mitogen-activated protein kinase (p38 MAPK) and cJUN N-terminal kinase (JNK), are implicated in the pathogenesis of ligation-induced acute pancreatitis in rats. As ligation-induced acute pancreatitis in rats is associated with CCK-A receptor induction and p38 MAPK activation, and as receptor induction could amplify acinar hyperstimulation and exacerbate cell stress, we tested the hypothesis that the cholinergic M3 receptor is induced and JNK is activated in this model. Methods Cholinergic M3 receptor expression and JNK activation was compared in rats 1, 3, or 24 hours after sham operation or duct ligation. Results Immunoblot analysis of pancreatic homogenates showed a time-dependent increase in cholinergic M3 receptor protein, total JNK, and phospho-JNK after duct ligation. Conclusions There is a rapid and progressive cholinergic M3 receptor induction and JNK activation in ligation-induced acute pancreatitis in rats. These findings may have significance in the mechanism of disease pathogenesis.

Akt-NFkB pathway is activated in duct ligation-induced acute pancreatitis in rats

Bile-pancreatic duct ligation in rats excludes bile-pancreatic juice from gut and induces acute pancreatitis. CCK-A and c:holinergic receptor-mediated exocr/ne pancreatic hyperstimulation secondat 7 to bile-pancreatic juice exclusion ~ implicated in disease pathogenesis. Stimulation of these G protein coupled receptors can activate the Akt-NFkB pathway Nuclear Transcrip~ lion Factor kappa B (NFkB) is a downstream messenger of acinar cell signal transduction via the Akt pathway and is capable o/inr Nag adnar cell cytokina production. We hypothesize that the Akt-NFkB pathway is activated in figation-induced acute pancreatitis. METHODS: We studied rats w~th 1, 3, or 24 hra ot duct ligation or sham-operation (ducts dLssected but not ligated)(n= 5 rats/group). RESULTS: Compared to sham-controls, duct ligation induced acute pancreatitis as evidenced by hyperamylasemia and pancreatic morphologic changes. Electro-mobility shift assay showed a irma-dependent incraase in NFkB in pancreatic nuclear extracts after duct ligation (transcnption factor E-box was used as control; competing cold NFkB prone excluded non-specihc binding), immunobIot analysis of pancreatic homogehates showed mcreases in phospho-Akt and phospho-lkB that were also time-dependent and parallel with NFkB activation (actin immunobiots confirmed equal loadtirg of lanes) (lkB phosphorylation permits translocatinn of NFkB from the cytosol to the nucleus). CONCLUSIONS: 'Paere is a time-dependem and parallel increase in nuclear translocation of NFkB and acuvation of Akt and IkB after duct ligationdnduced acute pancreatitis in rats. These findings are consistent wuh the h)~otbesis that the Akt-NFkB pathway is activated in duct ligation induced acute pancreatitis. In this expemnentaI corollary of gallstone-reduced acute pancreatitts, bile-pancreatic juice exclusion-induced stimulation of acinar cell G protein coupled receptors could exacerbate acute pancreatitis by increased acinar cell production of pro-inflammatory cytokines via lbe Akt-NFkB pathway (Support: Carver Collaborative Pilot Grant; N1H #lK08DK062805)

Complement Component C5 Deficiency Reduces Edema Formation in Murine Ligation-Induced Acute Pancreatitis

The complement cascade is activated in humans and animals with acute pancreatitis. Activation of complement component C5 liberates C5a, C5a-desarg, and terminal complement complexes (TCCs) that increase capillary permeability, edema, and leukocyte chemotaxis at injured sites. Complement activation plays a major role in pathogenesis of capillary leak and edema formation in severe acute pancreatitis; however, the contribution of C5(C5a/C5a-desarg, TCCs) has not been defined. UsingHcgene mutant mice lacking circulating C5, the role of C5 in ligation-induced acute pancreatitis was evaluated. We performed the following experiments: C5-sufficient (Hc1/Hc1) and C5-deficient (Hc0/Hc0) mice had bile and pancreatic ducts ligated. Sham-operated mice had ducts dissected but not ligated. Mice were killed at 4, 8, and 24 hr after bile–pancreatic duct ligation. Serologic and morphologic evidences of acute pancreatitis were evaluated. Pancreatic edema was assessed using analysis of pancreatic water content, histologic edema score, and determination of wet weight ratio. After 4, 8, and 24 hr of bile–pancreatic duct ligation, hyperamylasemia and histologic changes of acute pancreatitis were observed in both C5-deficient and C5-sufficient mice. Edema developed in all mice with acute pancreatitis. However, when compared to C5-sufficient mice, mice deficient in C5 developed significantly less pancreatic edema at both 8 and 24 hr of bile–pancreatic duct ligation. This difference was not observed 4 hr after induction of acute pancreatitis. We conclude that C5 contributes to edema formation in murine ligation-induced acute pancreatitis. The presence of an early C5-independent phase, in conjunction with the observation of significant edema in mice deficient in C5, suggests there are other mediators of edema formation in this acute pancreatitis model.

Salutary and prophylactic effect of pentadecapeptide BPC 157 on acute pancreatitis and concomitant gastroduodenal lesions in rats.

The superior effectiveness of a new pentadecapeptide, BPC 157, on gastrointestinal and liver lesions, in conjunction with an antiinflammatory and analgetic activity was recently noted. In the present study, BPC 157 was tested as either a protective or healing agent in bile duct ligation-induced acute pancreatitis in rats. In addition, the positive influence of BPC 157 on concomitantly developed gastric and duodenal lesions was simultaneously investigated. BPC 157 (10 microg, 10 ng/kg body wt, intraperitoneally or intragastrically) was given prophylactically 1 hr before ligation, whereas the therapy was given once daily beginning with the 24 hr following ligation (last application 24 hr before killing). The effect was investigated at daily intervals until the end of the fifth day after ligation. In the pretreatment regimen, a strong pancreas protection was obtained. When applied in the condition of already established severe acute pancreatitis, an obvious salutory effect was consistently noted. Assessing the appearance of the necrosis, edema, neutrophils, and mononuclears, consistently less necrosis, edema, and neutrophils, but more mononuclears, were found in BPC-treated rats. Likewise, in studies of the serum amylase values, relative to control data, a markedly lower rise (BPC pretreatment regimen) as well as a worsening of the already raised values (BPC therapy regimen) was noted. Along with its beneficial effect on pancreatitis, a positive influence of BPC 157 on the gastric and duodenal lesion course in bile duct-ligated rats was noted in both the pre- and posttreatment regimen. Taken together, in further studies of acute pancreatitis therapy, BPC could be an interesting and useful agent with an additional positive impact on concomitant gastroduodenal pathology.

Ligation-Induced Acute Pancreatitis Increases Pancreatic and Circulating Trypsinogen Activation Peptides

Ligation of the common bile–pancreatic duct induces hyperamylasemia and acute pancreatitis in rats. Pancreatic morphologic changes include edema, acinar cell damage, and mild inflammation. The pathogenesis of acute pancreatitis in this model is not understood, but may involve altered secretion and intrapancreatic activation of acinar proteases. We hypothesized that trypsinogen activation, measured by the production of plasma and pancreatic trypsinogen activation peptides (TAP), occurs early in this model. We performed the following experiments: rats were prepared with (1) bile–pancreatic ducts ligated and (2) ducts dissected but not ligated (sham). Rats were killed after 6, 24, and 48 hr. Serum amylase was measured and histologic sections were analyzed for morphologic changes. TAP was measured in both serum and pancreatic tissue homogenates using a specific polyclonal anti-TAP antibody in an enzyme-linked immunosorbant assay. After 6, 24, and 48 hr of bile–pancreatic duct ligation, hyperamylasemia and acute morphologic changes of acute pancreatitis were observed. Evidence of acinar cell destruction was not evident until 48 hr after ligation. Levels of serum and pancreatic tissue TAP were significantly elevated at both 24 and 48 hr after ligation compared to those of sham. We conclude that increased intrapancreatic trypsinogen activation occurs early in this form of experimental acute pancreatitis and that it occurs prior to evidence of acinar cell destruction. These data and observations support the possibility that intrapancreatic protease activation contributes to the pathogenesis of ligation-induced acute pancreatitis.

Bile and pancreatic juice replacement ameliorates early ligation-induced acute pancreatitis in rats

In healthy rats, combined bile and pancreatic juice diversion from gut has a synergistic rather than additive effect on stimulation of exocrine pancreatic protein secretion. We hypothesized that exclusion of combined bile and pancreatic juice from gut exacerbates bile and pancreatic-duct ligation-induced acute pancreatitis in rats to a greater extent than exclusion of either bile or pancreatic juice alone. Bile and pancreatic juice (obtained fresh from donor rats) were replaced, separately or together, via a duodenal fistula beginning immediately before 6 hours of duct ligation. Pancreatic morphologic changes were evaluated with an acute pancreatitis histology score and morphometric quantitation of acinar-cell necrosis. Plasma amylase and cholecystokinin concentrations and pancreatic subcellular distribution of cathepsin B activity were determined. Characteristics of bile and pancreatic juice obtained from donor rats were also studied. Combined bile and pancreatic juice replacement limited the increase in acute pancreatitis histology score by 77%, acinar cell necrosis by 95%, hyperamylasemia by 77%, and hypercholecystokininemia by 99%, while preventing subcellular redistribution of cathepsin B. Amelioration of pancreatic morphologic changes was significantly greater with combined bile and pancreatic juice replacement than with replacement of either bile or pancreatic juice alone. In this experimental corollary of early gallstone-induced acute pancreatitis, combined bile and pancreatic juice exclusion from gut contributes to disease pathogenesis to a greater extent than exclusion of either bile or pancreatic juice alone.