Etiopathogenesis of acute pancreatitis

Effect of liposome-mediated nuclear factor κB decoy oligodeoxynucleotide on the mRNA expression of inflammatory factors and injury of pancreas in rats with severe acute pancreatitis

AIM: To investigate the influences of liposome-mediated nuclear factor κB (NF-κB) decoy oligodeoxynucleotide (ODN) on the NF-κB activation, inflammatory factor mRNA expression and pancreatic injury in rats with severe acute pancreatitis (SAP).

METHODS: Except for those in sham operation group, the rest rats were injected with sodium taurocholate to establish the model of SAP, and then intravenously injected with naked ODN, liposome/decoy ODN complexes, liposome/scrambled ODN complexes, and normal saline, respectively, 1 h later. Four hours after injection, the NF-κB activity was analyzed by electrophoretic mobility shift assay (EMSA), and the mRNA expression of intercellular adhesion molecule-1 (ICAM-1), interleukin-1a (IL-1α), IL-2, tumor necrosis factor-a (TNF-α) and vascular cell adhesion molecule-1 (VCAM-1) were assessed by reverse transcription-polymerase chain reaction (RT-PCR). Meanwhile, the serum amylase level, pancreatic wet/dry weight ratio and myeloperoxidase (MPO) content were detected.

RESULTS: The NF-κB activity and its related inflammatory factors were observably inhibited in liposome/decoy ODN group as compared with those in normal saline group, liposome/scrambled ODN group and naked ODN group (NF-κB activation: P < 0.05; ICAM-1: 0.75 ± 0.13 vs 1.39 ± 0.15, 1.37 ± 0.16, 1.32 ± 0.17, all P < 0.05; IL-1α: 0.64 ± 0.09 vs 1.34 ± 0.20, 1.30 ± 0.14, 1.25 ± 0.20, all P < 0.05; IL-2: 0.23 ± 0.08 vs 0.74 ± 0.13, 0.71 ± 0.12, 0.69 ± 0.14, all P < 0.05; TNF-α: 0.41 ± 0.13 vs 1.30 ± 0.17, 1.26 ± 0.17, 1.23 ± 0.20, all P < 0.05; VCAM-1: 0.21 ± 0.06 vs 0.68 ± 0.13, 0.69 ± 0.15, 0.63 ± 0.13, all P < 0.05). In comparison with normal saline, liposome/scrambled ODN and naked ODN group, the level of serum amylase, the ratio of pancreaic wet/dry weight, and the MPO content of pancreatic tissues in liposome/decoy ODN group were remarkably decreased (amylase: 50931.85 ± 22432.15 nkat/L vs 188024.26 ± 38659.56, 188412.68 ± 37988.26, 183119.95 ± 33636.23 nkat/L, P < 0.05; wet/dry weight ration: 5.76 ± 0.20 vs 6.77 ± 0.18, 6.72 ± 0.18, 6.35 ± 0.12, P < 0.05; MPO: 46.68 ± 3.00 nkat/g vs 99.02 ± 2.50, 98.19 ± 2.83, 98.52 ± 2.50 nkat/g, P < 0.05).

CONCLUSION: NF-κB decoy ODN is effective in alleviating pancreatic injury during SAP through suppressing the activation of NF-κB and mRNA expression of ICAM-1, IL-1α, IL-2, TNF-α and VCAM-1.

Effect of portal vein occlusion on the pancreas: an experimental model

BACKGROUND

The effects of portal vein occlusion on the pancreas are not clearly understood. Therefore, we studied histomorphological changes induced in the rat pancreas by various periods of portal vein occlusion.

MATERIALS AND METHODS

Sixty female Wistar albino rats were randomly allocated into four groups of 15 each. In Group I (control), rats underwent sham laparotomy to expose the portal vein proximal to its bifurcation. In Groups II-IV, rats underwent laparotomy followed by portal vein occlusion by clamping for 15, 30, and 60 minutes respectively. The pancreas was removed immediately after sham laparotomy in Group I and immediately after clamp release in Groups II-IV. Pancreatic tissue specimens were subjected to histochemical analysis for cell typing and diagnosis, immunohistochemical analysis for identification of the inflammatory markers tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), endothelial nitric oxide synthase (eNOS), and inducible NOS (iNOS), and TUNEL analysis was carried out for identification of apoptotic cells.

RESULTS

Histochemistry revealed signs of inflammation in pancreatic tissue from rats subjected to portal vein occlusion. Immunohistochemistry revealed that the expression of proinflammatory cytokines TNF-alpha and IL-1beta and the oxidative damage indicator iNOS in rat pancreatic tissue increased progressively with the duration of portal vein occlusion. TUNEL assay revealed no signs of apoptosis in any of the groups.

CONCLUSION

We conclude that portal vein occlusion triggers an inflammatory response in the pancreas that worsens the longer the occlusion lasts.

In vitro evidence for role of ERK, p38, and JNK in exocrine pancreatic cytokine production

Elucidation of mechanisms of acinar cell cytokine production is essential for a better understanding of acute pancreatitis pathogenesis. We hypothesize that the stress kinases ERK, p38, and JNK play an important role in acinar cell cytokine production. Rat pancreatic fragments were incubated with 100 nM concentration of the cholecystokinin analog caerulein or 100 nM caerulein and specific ERK inhibitor (100 microM PD98059), specific p38 inhibitor (10 microM SB203580), or specific JNK inhibitor (20 microM SP600125). After 3 hours of caerulein treatment, pancreatic fragments were homogenized and assayed for total and phosphorylated ERK, p38, and JNK, and for tumor necrosis factor-alpha or interleukin-1beta concentrations (ELISA). Pancreatic fragments stimulated with caerulein showed activation of ERK, p38, and JNK and increased cytokine concentrations (ANOVA, P<0.05). Specific stress kinase inhibitors significantly attenuated caerulein-induced activation of the corresponding stress kinase and cytokine production; however, the effect of the JNK inhibitor was comparatively less convincing. Increased activation of ERK, p38, and JNK in pancreatic fragments was not associated with significant increases in total ERK, total p38, or total JNK concentrations. The stress kinases ERK and p38 play an important role in caerulein-stimulated exocrine pancreatic overproduction of cytokines. The role of JNK needs further evaluation in this experimental model.

Potential effects of hyperbaric oxygen therapy in acute pancreatitis

BACKGROUND

To extract from the biomedical published reports, the effects of hyperbaric oxygen (HBO) on inflammatory disease, in particular acute pancreatitis.

METHODS

This review will explain these effects and evaluate potential mechanisms of action of HBO in acute pancreatitis. A Medline/PubMed search (January 1966 to July 2004) with manual cross-referencing was conducted, including all relevant articles investigating the molecular and systemic effects of HBO on inflammatory diseases, particularly focusing on the studies of acute pancreatitis. All publication types, languages and subsets were searched.

RESULTS

Original and review articles and short communications were extracted. The selected original articles covered the molecular and systemic effects of HBO and the effects in inflammatory disease states. The major findings are that HBO can act as an anti-inflammatory agent and as an antimicrobial agent. Many of the effects of HBO would be beneficial in the treatment of acute severe pancreatitis. Work carried out to date in animal models of acute pancreatitis shows promising improvements in severity but studies are limited to date.

CONCLUSION

Acute pancreatitis impairs the pancreatic and systemic microcirculation and causes acute inflammation. These processes are potentially improved by HBO therapy.

Nuclear factor-kappaB activation on the reactive oxygen species in acute necrotizing pancreatitic rats

AIM: To investigate the potential role of nuclear factor kappa-B (NF-κB) activation on the reactive oxygen species in rat acute necrotizing pancreatitis (ANP) and to assess the effect of pyrrolidine dithiocarbamate (PDTC, an inhibitor of NF-κB).

METHODS: Rat ANP model was established by retrograde injection of 5% sodium taurocholate into biliopancreatic duct. Rats were randomly assigned to three groups (10 rats each): Control group, ANP group and PDTC group. At the 6^th h of the model, the changes of the serum amylase, nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD) and pancreatic morphological damage were observed. The expressions of inducible nitric oxide (iNOS) were observed by SP immunohistochemistry. And the expressions of NF-κB p65 subunit mRNA were observed by hybridization in situ.

RESULTS: Serum amylase and NO level decreased signifi-cantly in ANP group as compared with PDTC administrated group [(7 170.40 ± 1 308.63) U/L vs (4 074.10 ± 1 719.78) U/L, P < 0.05], [(76.95 ± 9.04) mol/L vs (65.18 ± 9.02) mol/L, P < 0.05] respectively. MDA in both ANP and PDTC group rose significantly over that in control group [(9.88 ± 1.52) nmol/L, (8.60 ± 1.41) nmol/L, vs (6.04 ± 1.78) nmol/L, P < 0.05], while there was no significant difference between them. SOD levels in both ANP and PDTC group underwent a significant decrease as compared with that in control [(3 214.59 ± 297.74) NU/mL, (3 260.62 ± 229.44) NU/mL, vs (3 977.80 ± 309.09) NU/mL, P < 0.05], but there was no significant difference between them. Though they were still higher than those in Control group, pancreas destruction was slighter in PDTC group, iNOS expression and NF-κB p65 subunit mRNA expression were lower in PDTC group as compared with ANP group.

CONCLUSION: We conclude that correlation among NF-κB activation, serum amylase, reactive oxygen species level and tissue damage suggests a key role of NF-κB in the pathogenesis of ANP. Inhibition of NF-κB activation may reverse the pancreatic damage of rat ANP and the production of reactive oxygen species.

Plasmapheresis in the management of acute severe hyperlipidemic pancreatitis: report of 5 cases

BACKGROUND/AIM

Hyperlipidemic pancreatitis is an acute and potentially life-threatening complication of hypertriglyceridemia that can be provoked when triglyceride levels (TGL) exceed 11.3 mmol/l (1,000 mg/dl). Except for standard symptomatic treatment, plasmapheresis has been performed to rapidly reduce TGL and chylomicron levels in the blood. In 5 patients with hyperlipidemic pancreatitis, treatment with plasmapheresis was evaluated.

METHODS

Five male patients who suffered from acute pancreatitis with severe primary hyperlipidemia were studied. In addition to the standard treatment, they were treated with plasmapheresis.

RESULTS

Plasma exchange lowered the lipid level and TGLs in all cases. It also improved abdominal pain, the clinical state of the patients, and signs and symptoms of the disease. Complications of treatment were not encountered, none of the patients died and only 1 patient underwent surgery. Follow-up of the patients lasted 4-28 months, and recurrence of pancreatitis was not noted.

CONCLUSION

Our study showed that plasmapheresis was successfully applied in patients with hyperlipidemic pancreatitis, especially to improve the acute phase of the disease.

Bile-pancreatic juice exclusion increases p38MAPK activation and TNF-alpha production in ligation-induced acute pancreatitis in rats

Acute pancreatitis is associated with stress kinase activation and cytokine production. We hypothesize that bile-pancreatic juice exclusion activates p38(MAPK) and induces TNF-alpha production in ligation-induced acute pancreatitis. We compared rats with 1-3 h of duct ligation, duct ligation with duodenal bile-pancreatic juice replacement from a donor rat, and sham operation. Pancreatic homogenates were analyzed as follows: (a) Immunoblots using phospho-specific p38(MAPK) antibody showed increased p38(MAPK) activation after ligation that was inhibited by bile-pancreatic juice replacement. (b) Immune-complex kinase assay using ATF-2 as substrate showed increased p38(MAPK) activation after ligation that was subdued by bile-pancreatic juice replacement. (c) ELISA showed increased pancreatic TNF-alpha production after ligation that was significantly ameliorated by bile-pancreatic juice replacement.

CONCLUSION

Bile-pancreatic juice exclusion from gut increases p38(MAPK) activation and TNF-alpha production in this experimental model. Our findings support our central hypothesis that bile-pancreatic juice exclusion exacerbates cell stress and acute inflammation in ligation-induced acute pancreatitis.

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.

O mosaico patogênico da pancreatite aguda grave

A pancreatite aguda tem sido alvo de grandes discussões que vão desde o entendimento de sua fisiopatologia até a investigação de novas modalidades terapêuticas. Reconhece-se que a necrose pancreática e a falência orgânica múltipla - mormente associadas à infecção - representam os principais fatores determinantes da evolução para o óbito, mas, apesar dos grandes avanços em seu estudo, a doença permanece como um desafio para o clínico e o cirurgião. Deste modo, um melhor conhecimento dos mecanismos envolvidos em sua fisiopatologia pode ser a chave para um tratamento mais eficaz, principalmente em relação às formas graves, cuja letalidade ainda encontra-se substancialmente elevada. Baseado nestas considerações, o presente trabalho tem por objetivo a revisão bibliográfica da fisiopatologia, dos fatores patogênicos envolvidos na história natural da pancreatite aguda grave e dos eventos associados à síndrome da resposta inflamatória sistêmica e à sepse, esboçando-se assim o mosaico patogênico desta importante condição.

Melatonin protects against pancreaticobiliary inflammation and associated remote organ injury in rats: role of neutrophils

Although the role of oxidative stress in acute pancreatitis (AP) has been studied in several animal models, little data are available regarding AP induced by pancreatic duct obstruction. We characterized the protective effects of melatonin on pancreaticobiliary inflammation and associated remote organ injury. In Sprague-Dawley rats, either the common pancreaticobiliary duct (PBDL; n = 28) or bile duct (BDL; n = 28) was ligated or a sham operation was applied (n = 14). Either melatonin (10 mg/kg) or vehicle (saline; 1 mL/kg) was administered intraperitoneally (i.p.) immediately before the surgery and twice a day until the rats were decapitated at 6 or 72 h. The pancreas, liver, kidneys and lungs were removed and tissue samples were stored for the determination of malondialdehyde (MDA) and glutathione (GSH) levels and myelopreoxidase activity. The results demonstrate that pathogenesis of acute obstructive pancreatitis involves not only the oxidative damage of the pancreatic and hepatic tissues, as assessed by increased MDA and reduced GSH levels, but the lungs and kidneys are also challenged by oxidant injury. Similarly, hepatic oxidative injury caused by cholestasis was also accompanied by pulmonary, renal and even pancreatic damage. The biochemical findings were also verified histologically. Melatonin, probably because of its free-radical scavenging and antioxidant activity, which involves an inhibitory effect on tissue neutrophil infiltration, protected all the affected tissues.

Imaging and Percutaneous Management of Acute Complicated Pancreatitis

Acute pancreatitis varies from a mild, self-limited disease to one with significant morbidity and mortality in its most severe forms. While clinical criteria abound, imaging has become indispensable to diagnose the extent of the disease and its complications, as well as to guide and monitor therapy. Percutaneous interventional techniques offer options that can be life-saving, surgery-sparing or important adjuncts to operation. Close cooperation and communication between the surgeon, gastroenterologist and interventional radiologist enhance the likelihood of successful patient care.

Fas deficiency exacerbates cerulein-induced pancreatitis

Acute pancreatitis results in many deaths each year. Our understanding of pathophysiology is limited. To better understand the impact of apoptosis versus necrosis, we compared cerulein-induced pancreatitis in Fas-deficient (MRL lpr/lpr) versus Fas-sufficient (MRL +/+) mice. Average amylase values in Fas-deficient mice were substantially greater than in Fas-sufficient mouse. Histology graded on edema, inflammation, vacuolization, and necrosis showed greater injury in the Fas-deficient mouse. This finding suggests that the Fas pathway is important in controlling cerulein-induced pancreatitis.

Vigilin and enzyme expression in isolated pancreatic acini after mellitin and gamma-interferon treatment

BACKGROUND/AIMS

Pancreatitis goes along with changes in exocrine enzyme synthesis and secretion in pancreatic acini. The multi-KH domain protein vigilin is supposed to play an important role in t-RNA trafficking especially in cells with high protein synthesis rates and may reflect the degree of stimulation of translational machinery during pathological processes. In relation to these phenomena we explored in this connection the impact of two different inflammation mediators in a system of isolated rat pancreatic acini.

METHODS

Acini were prepared from male Sprague-Dawley rats by collagenase digestion and incubated with mellitin or gamma interferon. Secretion and cytosolic cell content of pancreatic trypsin and amylase as well as the expression of vigilin were determined.

RESULTS

The phospholipase A(2) activator mellitin caused morphological alterations and increased release of trypsin and amylase, while vigilin expression and the intracellular content of these enzymes decreased. Gamma-interferon, a cytokine which is involved at different steps in inflammation processes, selectively inhibits the release of trypsin(ogen) while not affecting amylase secretion and vigilin expression.

CONCLUSION

Mellitin as well as gamma interferon causes alterations in pancreatic enzyme secretion. Additionally, mellitin seems to influence the expressed gene pattern of pancreatic acini while interferon-gamma has no effect on protein synthesis but enzyme secretion.

Diclofenac reduces the incidence of acute pancreatitis after endoscopic retrograde cholangiopancreatography

BACKGROUND & AIMS

Acute pancreatitis following endoscopic retrograde cholangiopancreatography presents a unique opportunity for prophylaxis and early modification of the disease process because the initial triggering event is temporally well defined and takes place in the hospital. We report a prospective, single-center, randomized, double-blind controlled trial to determine if rectal diclofenac reduces the incidence of pancreatitis following cholangiopancreatography.

METHODS

Entry to the trial was restricted to patients who underwent endoscopic retrograde pancreatography or had manometrically verified sphincter of Oddi hypertension. Immediately after endoscopy, patients were given a suppository containing either 100 mg diclofenac or placebo. Estimation of serum amylase levels and clinical evaluation were performed in all patients.

RESULTS

A total of 220 patients entered the trial, and 110 received rectal diclofenac. Twenty-four patients developed pancreatitis (11%), of whom 7 received rectal diclofenac and 17 received placebo (P < 0.05).

CONCLUSIONS

This trial shows that rectal diclofenac given immediately after endoscopic retrograde cholangiopancreatography can reduce the incidence of acute pancreatitis.

Mechanism of kinin release during experimental acute pancreatitis in rats: evidence for pro- as well as anti-inflammatory roles of oedema formation

1 Kinin B(2) receptor antagonists or tissue kallikrein (t-KK) inhibitors prevent oedema formation and associated sequelae in caerulein-induced pancreatitis in the rat. We have now further investigated the mechanism of kinin generation in the pancreas. 2 Kinins were elevated in the pancreatic tissue already before oedema formation became manifest. Peak values (421+/-59 pmol g(-1) dry wt) were reached at 45 min and remained elevated for at least 2 h; a second increase was observed at 24 h. Pretreatment with the B(2) receptor antagonist icatibant abolished kinin formation, while post-treatment was ineffective. 3 Total kininogen levels were very low in the pancreas of controls, but increased 75-fold during acute pancreatitis. This increase was absent in rats that were pretreated with icatibant. 4 During pancreatitis, t-KK-like and plasma kallikrein (p-KK)-like activity in the pancreas, as well as trypsinogen activation peptide (TAP) increased significantly. Icatibant pretreatment further augmented t-KK about 100-fold, while p-KK was significantly attenuated; TAP levels remained unaffected. 5 Endogenous protease inhibitors (alpha(1)-antitrypsin, alpha(2)-macroglobulin) were low in normal tissues, but increased 45- and four-fold, respectively, during pancreatitis. This increase was abolished when oedema formation was prevented by icatibant. 6 In summary, oedema formation is initiated by t-KK; the ensuing plasma protein extravasation supplies further kininogen and active p-KK to the tissue. Concomitantly, endogenous protease inhibitors in the oedema fluid inhibit up to 99% of active t-KK. Our data thus suggest a complex interaction between kinin action and kinin generation involving positive and negative feedback actions of the inflammatory oedema.

Coagulative disorders in human acute pancreatitis: role for the D-dimer

INTRODUCTION AND AIMS

We investigated coagulative disorders, particularly the role of the D-dimer, in acute pancreatitis where coagulation abnormalities related to disease severity are known to occur.

METHODOLOGY

D-dimer levels in 30 patients with acute pancreatitis were evaluated; pancreatitis was mild and uncomplicated in 11 patients, accompanied by complications in 15, and severe in 4. We attempted to find a relationship between the D-dimer level and the antithrombin III level, prothrombin time, partial thromboplastin time, the C-reactive protein level, and results of routine laboratory tests.

RESULTS

In the 11 patients with uncomplicated pancreatitis, the D-dimer level increased about 1.5 times over the limit, while in the 15 patients with complications and the four patients with severe pancreatitis, the D-dimer level increased about seven times above the normal limit; this difference was highly significant (p < 0.0001). The rise in the D-dimer level was inversely related to albumin and calcium levels (p = 0.0001) and directly related to the C-reactive protein level, fibrinogen level and leukocyte count (p = 0.0001), prothrombin time (p = 0.006), partial thromboplastin time (p = 0.03), and acute abdominal collections and lung involvement (p = 0.0001). The increase appeared early on, lasting for the entire study and peaking on days 3-6.

CONCLUSIONS

The D-dimer is the expression of pancreatitis and the extension of systemic involvement; it may be considered a prominent link in the chain of events leading to severe disease.

Serum antigen(s) drive the proinflammatory T cell response in acute pancreatitis

BACKGROUND

Immune cells and cytokines are central to the systemic inflammatory response syndrome and multiple organ failure associated with acute pancreatitis. The specific role of T cells in this response is unclear, and this study focused on evaluating T cell activation and its regulation in patients with acute pancreatitis.

METHODS

Peripheral blood samples of 14 patients with acute pancreatitis were obtained within 24 h of the onset of pain, within 48 h and at 1 week. T cell expression of surface markers CD69, CD62L and CD25 was measured. The production of interleukin (IL) 10 and IL-2 in vitro in response to the superantigen Staphylococcus enterotoxin B (SEB) was assessed. Serum samples from these patients were co-cultured with peripheral blood mononuclear cells from volunteers in the presence or absence of cytotoxic T lymphocyte-associated antigen (CTLA) 4 immunoglobulin, a specific inhibitor of antigen-dependent T cell activation.

RESULTS

Expression of CD69 was significantly increased in CD3(+) and CD4(+) populations at 48 h and 1 week, and on CD8(+) cells at 1 week. There was a significant increase in the production of SEB-induced IL-2 compared with findings in controls, but no significant IL-10 response. Serum from patients with pancreatitis activated normal T cells. This response was abolished completely by CTLA-4.

CONCLUSION

Acute pancreatitis results in the systemic activation of T cells. These cells are primed for a proinflammatory response to antigen stimulation and can be inhibited by antigen-specific T cell blockade. These data indicate that the immunoinflammatory response in acute pancreatitis is fueled by one or more serum antigens and offer prospects for further understanding of the aetiogenesis of pancreatitis.

Apoptosis in the peripheral blood mononuclear cells as a self-limitation process in human acute pancreatitis

BACKGROUND/AIM

Acute pancreatitis is primed and sustained by a chain of immuno-inflammatory factors. In this study, we investigated the possible existence of peripheral blood mononuclear cell apoptosis as a self-limitation mechanism in acute pancreatitis.

METHODS

Peripheral blood mononuclear cell apoptosis was determined cytofluorometrically daily for 10 days from the onset of the illness in 27 consecutive patients (18 having mild uncomplicated acute pancreatitis and 9 having pancreatitis with complications) and was related to peripheral blood counts, including reticulocytes and reticulocyte fractions, and albumin, fibrinogen, and C-reactive protein levels.

RESULTS

In the 18 patients with uncomplicated acute pancreatitis, the rate of peripheral blood apoptosis increased progressively until days 5-6 and then decreased. The 9 patients who developed complications showed levels of peripheral blood apoptosis stable across the five periods and lower than those with uncomplicated disease during the first four periods. This difference was statistically significant (p = 0.002) only on days 7-8. On days 9-10, the patients with complications showed higher levels of peripheral blood apoptosis than those with mild uncomplicated acute pancreatitis (p = 0.0005). Peripheral blood apoptosis was not significantly related to the other laboratory parameters, but there was a trend towards an inverse relation to reticulocytes and total leucocytes (p < 0.09).

CONCLUSIONS

Peripheral blood apoptosis may act as a mechanism of self-limitation of the process of acute pancreatitis. Its effects, however, seem to be hampered and delayed by the presence of complications.

New laboratory tests in acute pancreatitis

Acute pancreatitis (AP) is a common disease with wide variation of severity. The diagnosis of AP is usually based on high serum amylase or lipase values but the accuracy of these methods is considered unsatisfactory. One in five of the patients develops a severe disease and carries a considerable risk of development of organ failure and high mortality. Early detection of patients with severe AP and especially those with increased risk of organ failure is importance since such patients seem to benefit from treatment in an intensive care unit started as soon as possible after presentation. In addition to enzymological methods, increasing interest has been focused on laboratory markers reflecting the level of inflammatory response in AP. At present, in routine clinical work the most commonly used severity marker is serum C-reactive protein, the concentration of which rises too slowly to be used for early prediction of severity. New therapies aiming at modifying the course of systemic inflammation in AP are being developed and therefore monitoring the patient's immune inflammatory status is needed. In this review article we present the current knowledge of laboratory tests, which has been evaluated for diagnostic and prognostic purposes in AP.

Cloning and expression of the rat vacuole membrane protein 1 (VMP1), a new gene activated in pancreas with acute pancreatitis, which promotes vacuole formation

To characterize the emergency program set up by pancreatic cells in response to pancreatitis, we established the phenotype of the pancreatitis-affected pancreas by characterizing a large number of its transcripts. In this report, we describe the cloning, sequencing, and expression pattern of a new gene, named VMP1 (vacuole membrane protein 1). The VMP1 mRNA codes for a putative protein of 406 amino acids. In situ hybridization studies revealed that pancreatic expression of VMP1 mRNAs was restricted to the acinar cells. Interestingly, VMP1 mRNA was also overexpressed in kidney after transient ischemic injury. However, many healthy tissues express VMP1 mRNA. Structure analysis suggested that VMP1 is a transmembrane protein with six hydrophobic regions. VMP1/EGFP fusion protein was located to the Golgi apparatus and the endoplasmic reticulum area. Expression of this protein promoted the formation of intracytoplasmatic vacuoles and VMP1/EGFP was located to the membranes of these vacuoles. Cells overexpressing this protein died after 48 h. In conclusion, we have identified a new stress-induced gene which codes for a transmembrane protein that, when overexpressed, promotes formation of intracellular vacuoles followed by cell death.

Pathogenesis and immune response in Atlantic salmon (Salmo salar L.) parr experimentally infected with salmon pancreas disease virus (SPDV)

Atlantic salmon parr were injected intraperitoneally with salmon pancreas disease virus (SPDV) grown on CHSE-214 cells. The viraemia, the histopathological changes in target organs and some immune parameters were taken at intervals up to 30 days post-infection (dpi). The earliest kind of lesion was necrosis of exocrine pancreas, appearing as soon as 2 dpi. It progressed towards complete tissue breakdown at 9 dpi before resolving gradually. Concurrent to this necrosis, a strong inflammatory response was in evidence from 9 dpi in the pancreatic area for a majority of fish. A necrosis of the myocardial cells of the ventricle occurred in infected fish mainly at 16 dpi and it faded thereafter. The monitoring of the plasma viral load showed a rapid haematogenous spreading of SPDV, peaking at 4 dpi, but also the absence of a secondary viraemia. No interferon (IFN) was detected following the infection of parr with SPDV, probably owing to an IFN activity in Atlantic salmon below the detection level of the technique. Neutralising antibodies against SPDV were in evidence from 16 dpi and they showed a time-related increasing titre and prevalence. The phagocytic activity in head-kidney leucocytes was always significantly higher in the infected fish than in the control fish, being particularly high by 9 dpi. Lysozyme and complement levels were both increased and they peaked significantly in the infected fish at 9 and 16 dpi respectively. These results demonstrated that an experimental infection of Atlantic salmon parr with SPDV provoked a stimulation of both specific and non-specific immunity with regards to the viraemia and the histopathology.

Molecular and functional characterization of the stress-induced protein (SIP) gene and its two transcripts generated by alternative splicing. SIP induced by stress and promotes cell death

We have used a quantitative fluorescent cDNA microarray hybridization approach to identify pancreatic genes induced by the cellular stress promoted by acute pancreatitis in the mouse. We report the cloning and characterization of one of them that encodes the stress-induced proteins (SIP). The mouse SIP gene is organized into five exons and expands over approximately 20 kilobase pairs. Exon 4 (38 base pairs) is alternatively spliced to generate two transcripts. Northern blot and in situ hybridization showed that both SIP mRNAs are rapidly and strongly induced in acinar cells of the pancreas with acute pancreatitis. They are also constitutively expressed in several other tissues, although with different ratios. They encode proteins of 18 and 27 kDa (SIP(18) and SIP(27)). SIP(27) is identical to the thymus-expressed acidic protein (TEAP) protein, formerly described as a thymus-specific protein. Expression of the SIP(18) and SIP(27)/EGFP or V5 fusion proteins showed that both are nuclear factors. We monitored SIP expression in NIH3T3 cells submitted to various stress agents. UV stress, base damaging, mutagenic stress, ethanol, heat shock, and oxidative stress induced the concomitant expression of SIP(18) and SIP(27) mRNAs. Finally, transient transfection of SIP(18) and SIP(27) expression plasmids induced death by apoptosis in COS7 cells as measured by terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling staining. In conclusion, the SIP gene is an important element of cellular stress response. It is expressed in many tissues and induced by a variety of stress agents affecting many cellular pathways. SIP generates, by alternative splicing, two nuclear proteins that can promote cell death by apoptosis.

Type I hyperlipoproteinemia due to a novel loss of function mutation of lipoprotein lipase, Cys(239)-->Trp, associated with recurrent severe pancreatitis

Lipoprotein lipase (LPL) is the major enzyme responsible for the hydrolysis of triglyceride-rich lipoproteins in plasma. The purpose of this study was to examine the molecular pathogenesis of type I hyperlipoproteinemia in a patient suffering from recurrent severe pancreatitis. Apolipoprotein (apo) CII concentration was normal as well as apo CII-activated LPL in an in vitro assay. In postheparin plasma neither LPL mass nor activity was detectable, whereas hepatic lipase activity was normal. Direct sequencing of all 10 exons of the LPL gene revealed that the patient was homozygous for a hitherto unknown mutation in exon 6, Cys(239)-->Trp. The mutation prevents the formation of the second disulfide bridge of LPL, which is an essential part of the lid covering the catalytic center. Consequently, misfolded LPL is rapidly degraded within the cells, causing the absence of LPL immunoreactive protein in the plasma of this patient. In conclusion, we have identified a novel loss of function mutation in the LPL gene (Cys(239)-->Trp) of a patient with type I hyperlipoproteinemia suffering from severe recurrent pancreatitis. After initiation of heparin therapy (10,000 U/day sc), the patient experienced no more episodes of pancreatitis, although heparin therapy did not affect serum triglyceride levels.

Activation of polyamine catabolism in transgenic rats induces acute pancreatitis

Polyamines are required for optimal growth and function of cells. Regulation of their cellular homeostasis is therefore tightly controlled. The key regulatory enzyme for polyamine catabolism is the spermidine/spermine N(1)-acetyltransferase (SSAT). Depletion of cellular polyamines has been associated with inhibition of growth and programmed cell death. To investigate the physiological function SSAT, we generated a transgenic rat line overexpressing the SSAT gene under the control of the inducible mouse metallothionein I promoter. Administration of zinc resulted in a marked induction of pancreatic SSAT, overaccumulation of putrescine, and appearance of N(1)-acetylspermidine with extensive depletion of spermidine and spermine in transgenic animals. The activation of pancreatic polyamine catabolism resulted in acute pancreatitis. In nontransgenic animals, an equal dose of zinc did not affect pancreatic polyamine pools, nor did it induce pancreatitis. Acetylated polyamines, products of the SSAT-catalyzed reaction, are metabolized further by the polyamine oxidase (PAO) generating hydrogen peroxide, which might cause or contribute to the pancreatic inflammatory process. Administration of specific PAO inhibitor, MDL72527 [N(1),N(2)-bis(2,3-butadienyl)-1,4-butanediamine], however, did not affect the histological score of the pancreatitis. Induction of SSAT by the polyamine analogue N(1),N(11)-diethylnorspermine reduced pancreatic polyamines levels only moderately and without signs of organ inflammation. In contrast, the combination of N(1), N(11)-diethylnorspermine with MDL72527 dramatically activated SSAT, causing profound depletion of pancreatic polyamines and acute pancreatitis. These results demonstrate that acute induction of SSAT leads to pancreatic inflammation, suggesting that sufficient pools of higher polyamine levels are essential to maintain pancreatic integrity. This inflammatory process is independent of the production of hydrogen peroxide by PAO.

Hereditary pancreatitis and mutations of the cationic trypsinogen gene

BACKGROUND

Mutations of the cationic trypsinogen gene have been detected in hereditary pancreatitis. This article reviews current understanding of their function and clinical significance.

METHODS

An unrestricted Medline search was conducted using the key words hereditary pancreatitis and 'cationic trypsinogen . Additional material was obtained from references cited in original papers and recently published abstracts of meetings.

RESULTS AND CONCLUSION

Cationic trypsinogen mutations have been identified in most, but not all, families with hereditary pancreatitis. This confirms existing evidence that premature trypsinogen activation plays a central role in the pathogenesis of human pancreatitis. Patients currently clinically defined as having hereditary pancreatitis should be screened for the presence of cationic trypsinogen mutations. A subgroup of patients with non-hereditary pancreatitis may also benefit from being screened for these mutations. Patients with hereditary pancreatitis should be entered into prospective, multicentre trials investigating secondary screening for pancreatic cancer. Gene therapy for hereditary pancreatitis is beyond current technological capability but remains a future therapeutic prospect for this often debilitating condition.