Pancreas: healing response in critical illness

Scombroid pancreatitis from mahi-mahi consumption

A 61-year-old woman with no significant previous medical history presented to an urgent care facility with generalised rash, flushing and abdominal pain after eating mahi-mahi. She was diagnosed with an allergic reaction and discharged home. Later she experienced severe acute abdominal pain and multiple episodes of vomiting, which prompted her to go to the hospital. On admission, the patient had an elevated white count, lipase, amylase and C reactive protein with normal liver enzymes and bilirubin. Imaging showed acute pancreatitis that was suspected to be secondary to scombroid poisoning. This was confirmed by elevated immunoglobulin E and histamine levels. The acute pancreatitis was treated with pain management and supportive treatment. Scombroid poisoning is a well-recognised disease, however, acute pancreatitis secondary to this is rare as only two cases have been reported in the literature, one with codfish and the second an unknown type of fish.

Antigen recognition in the islets changes with progression of autoimmune islet infiltration

In type 1 diabetes, the pancreatic islets are an important site for therapeutic intervention because immune infiltration of the islets is well established at diagnosis. Therefore, understanding the events that underlie the continued progression of the autoimmune response and islet destruction is critical. Islet infiltration and destruction is an asynchronous process, making it important to analyze the disease process on a single islet basis. To understand how T cell stimulation evolves through the process of islet infiltration, we analyzed the dynamics of T cell movement and interactions within individual islets of spontaneously autoimmune NOD mice. Using both intravital and explanted two-photon islet imaging, we defined a correlation between increased islet infiltration and increased T cell motility. Early T cell arrest was Ag dependent and due, at least in part, to Ag recognition through sustained interactions with CD11c(+) APCs. As islet infiltration progressed, T cell motility became Ag independent, with a loss of T cell arrest and sustained interactions with CD11c(+) APCs. These studies suggest that the autoimmune T cell response in the islets may be temporarily dampened during the course of islet infiltration and disease progression.

Effect of Zhuyeshigao granule on tumor necrosis factor-alpha and interleukins serum protein levels in rats with radiation esophagitis

OBJECTIVE

To investigate the effects of Zhuyeshigao granule (ZSG) on tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), IL-2, IL-6, and IL-8 in rats with radiation esophagitis.

METHODS

Fifty Wistar rats were randomly divided into five groups (10 rats in each group): control (without radiation), saline-treated, and low, medium, and high-dose ISG-treated groups. Rats were given normal saline (10 mL/kg) or 1.15, 2.3, or 4.6 g/kg ZSG by intragastric administration once a day for 7 days. A rat model of radiation esophagitis was established by local irradiation of Co60 (490.25 cGy/min, totaling 30 Gy). The administration of ZSG was continued for another 7 days and on the 7th day post-irradiation, inferior vena cava blood was collected. The serum was separated, and TNF-alpha, IL-1, IL-2, IL-6, and IL-8 protein levels were determined.

RESULTS

Inflammatory response factors were found in the serum of each group. However, levels in ZSG-treated groups were significantly lower than in the saline-treated group (P < 0.05).

CONCLUSION

ZSG may prevent the development of radiation esophagitis, perhaps by inhibiting the generation and release of the inflammatory response factors TNF-alpha, IL-1, IL-2, IL-6, and IL-8.

L-cysteine administration attenuates pancreatic fibrosis induced by TNBS in rats by inhibiting the activation of pancreatic stellate cell

BACKGROUND AND AIMS

Recent studies have shown that activated pancreatic stellate cells (PSCs) play a major role in pancreatic fibrogenesis. We aimed to study the effect of L-cysteine administration on fibrosis in chronic pancreatitis (CP) induced by trinitrobenzene sulfonic acid (TNBS) in rats and on the function of cultured PSCs.

METHODS

CP was induced by TNBS infusion into rat pancreatic ducts. L-cysteine was administrated for the duration of the experiment. Histological analysis and the contents of hydroxyproline were used to evaluate pancreatic damage and fibrosis. Immunohistochemical analysis of α-SMA in the pancreas was performed to detect the activation of PSCs in vivo. The collagen deposition related proteins and cytokines were determined by western blot analysis. DNA synthesis of cultured PSCs was evaluated by BrdU incorporation. We also evaluated the effect of L-cysteine on the cell cycle and cell activation by flow cytometry and immunocytochemistry. The expression of PDGFRβ, TGFβRII, collagen 1α1 and α-SMA of PSCs treated with different concentrations of L-cysteine was determined by western blot. Parameters of oxidant stress were evaluated in vitro and in vivo. Nrf2, NQO1, HO-1, IL-1β expression were evaluated in pancreas tissues by qRT-PCR.

RESULTS

The inhibition of pancreatic fibrosis by L-cysteine was confirmed by histological observation and hydroxyproline assay. α-SMA, TIMP1, IL-1β and TGF-β1 production decreased compared with the untreated group along with an increase in MMP2 production. L-cysteine suppressed the proliferation and extracellular matrix production of PSCs through down-regulating of PDGFRβ and TGFβRII. Concentrations of MDA+4-HNE were decreased by L-cysteine administration along with an increase in GSH levels both in tissues and cells. In addition, L-cysteine increased the mRNA expression of Nrf2, NQO1 and HO-1 and reduced the expression of IL-1β in L-cysteine treated group when compared with control group.

CONCLUSION

L-cysteine treatment attenuated pancreatic fibrosis in chronic pancreatitis in rats.

Pancreatitis: understanding the disease and implications for care

Pancreatitis, or inflammation of the pancreas, has a variety of etiologies. Severity of the disease can range from its mildest form, which resolves quickly with few complications, to its most severe form, necrotizing pancreatitis, which is associated with an increased risk for developing multiple system organ failure and mortality. Treatment of pancreatitis aims to eliminate the etiologic factors for the disease while managing its complications and preventing further disease progression. Patients with mild forms of pancreatitis may improve with symptom management, whereas those with more severe disease will need significant supportive interventions. Most patients are managed medically. Surgery may be indicated for severe pancreatitis. It is important to understand the disease process and its impact on other organ systems when caring for these patients. Accurate assessment of changes in the patient's condition can lead to interventions that can limit complications and reduce the risk of mortality. This article reviews the pathophysiology of pancreatitis, its diagnosis and treatment, associated complications and their management, and essential nursing assessment and interventions.

Alcoholic pancreatitis: Lessons from the liver

The association between alcohol consumption and pancreatitis has been recognized for over 100 years. Despite the fact that this association is well recognized, the mechanisms by which alcohol abuse leads to pancreatic tissue damage are not entirely clear. Alcohol abuse is the major factor associated with pancreatitis in the Western world. Interestingly, although most cases of chronic pancreatitis and many cases of acute pancreatitis are associated with alcohol abuse, only a small percentage of individuals who abuse alcohol develop this disease. This situation is reminiscent of the association between alcohol abuse and the incidence of alcoholic liver disease. The liver and the pancreas are developmentally very closely related. Even though these two organs are quite different, they exhibit a number of general structural and functional similarities. Furthermore, the diseases mediated by alcohol abuse in these organs exhibit some striking similarities. The diseases in both organs are characterized by parenchymal cell damage, activation of stellate cells, aberrant wound healing, and fibrosis. Because of the similarities between the liver and the pancreas, and the alcohol-associated diseases of these organs, we may be able to apply much of the knowledge that we have gained regarding the effects of alcohol on the liver to the pancreas.

Pancreatic injury response is different depending on the method of resecting the parenchyma

OBJECTIVES

The present study was performed to compare the pancreatic injury response on the parenchymal resection either with ultrasonic scissors, electrocautery, or surgical scalpel.

METHODS

A 1 x 0.5 cm piece of rat pancreas was resected from side of the pancreas either with ultrasonic scissors (Harmonic Scalpel; UltraCision, Ethicon Endosurgery Inc., Cincinnati, OH) or electrocautery (Force FX; Valleylab, Tyco Healthcare Group LP, Boulder, CO) at two power levels, 1 and 3; 8W and 25W, respectively, or with surgical scalpel. Hemostasis was provided after surgical scalpel either with cellulose patch (Interceed; Johnson and Johnson Medical, Inc., New Brunswick, NJ), three stitches of 6-0 polydioxanone at tightness of 0.6N or fibrin glue (Tisseel Duo Quick; Baxter AG, Wien, Austria). Blood sample and pancreas specimens, both at the resection site and far away, were taken 1, 7, and 21 days postoperatively from exposed animals, sham operated animals (n = 18 in each) and from unexposed baseline animals (n = 5). Necrosis, edema, leukocyte infiltration, hemorrhage, vacuolization, and fibrosis were histologically assessed separately.

RESULTS

Each resection and sham operation induced similar increase in the amylase activity on day 1 with normalization by day 7. Resection with ultrasonic scissors and electrocautery induced more tissue injury to the pancreas than resection with surgical scalpel independent of the method for hemostasis. The injury, although somewhat milder in intensity, was also observed in parts of the pancreas located far away from the site of resection.

CONCLUSIONS

Of the compared methods, surgical scalpel resection plus cellulose patch or fibrin glue hemostasis induced the least histological changes in the pancreatic parenchyma. This injury response spread over the pancreas.

Obesity and fat distribution imply a greater systemic inflammatory response and a worse prognosis in acute pancreatitis

BACKGROUND AND AIMS

Acute pancreatitis (AP) is a systemic inflammatory disease. It is already known that obesity and central fat distribution are related to the severity of AP, but the intimate mechanism of this relationship remains unknown. Obesity and central fat distribution are associated with an inflammatory state that could amplify the systemic inflammatory response (SIR) in AP. The aim of this study was to investigate how obesity and body fat distribution correlate with the SIR and severity of AP.

METHODS

85 consecutive patients with AP were studied. Body mass index, body fat distribution and previous comorbidity were obtained at admission. The SIR was assessed by the serum levels of interleukin (IL)-1beta, IL-1ra, IL-6, IL-8, IL-10, IL-12p70, tumor necrosis factor-alpha (TNF-alpha) and C-reactive protein. Serum concentrations of the previously mentioned cytokines were also determined in a control group of 40 healthy volunteers.

RESULTS

63 patients (74%) had mild AP and 22 patients (26%) had severe AP. All the cytokines except IL-12p70 and TNF-alpha were increased in the AP group in comparison with the control group. The SIR was significantly increased in patients with severe AP. Obese patients and patients with central fat distribution had significantly more comorbidity, a higher proportion of severe AP and more intense SIR. Patients with comorbidity had a significantly higher proportion of severe AP and more SIR.

CONCLUSION

The severity of AP in obese patients and in patients with central fat distribution seems to be related to the comorbidity and the amplification of SIR. and IAP.

Tissue adhesives and the pancreas: biocompatibility and adhesive properties of 6 preparations

OBJECTIVES

The aim of this study was to investigate biocompatibility and adhesive properties of 6 tissue adhesives available, when applied between the pancreas and jejunum in an experimental model.

METHODS

Portion of jejunum was glued on the pancreas in rats with 3 cyanoacrylate derivatives (Histoacryl, Dermabond, and Glubran 2), 2 human fibrin sealants (Tisseel Duo Quick and Quixil), and 1 albuminglutaraldehyde sealant (BioGlue). Pancreatic tissue specimens and blood samples were harvested 1, 3, 7, and 21 days after gluing for histological determination and amylase activity measurement. Pancreaticojejunal attachment created with adhesives underwent tensile strength measurement at each time point. Samples were also taken from unoperated rats and sham-operated rats.

RESULTS

Exposure and sham groups both induced a similar increase in amylase activity on day 1 with normalization by day 3. Sham operation induced mild changes in the pancreas. Each tissue adhesive induced changes in pancreatic histology to the entire gland. Injurious effect was more severe with the 3 cyanoacrylates than with the 3 fibrin/semisynthetic glues. Histoacryl and Quixil induced lower tensile strength than the other adhesives.

CONCLUSIONS

All of the tissue adhesives studied induced histological changes in the pancreas of which at least part might be considered harmful. The potentially harmful tissue effects of the preparations tested might compromise the use of these substances in pancreatic surgery.

Advances in research of severe acute pancreatitis complicated by lung injury

Lung injury is one of the most common complications of severe acute pancreatitis (SAP). At present, the pathogenesis of SAP complicated by lung injury still remains unclear. However, great attention has been paid to it at home and abroad. Many factors such as pancreatic enzyme, polymorphonuclear neutrophil, oxygen free radical, cytokine, microcirculatory disturbance, complement, kinin, NO and ET play an important role in the pathogenesis of SAP by interacting with each other. This paper reviews the advances in the pathogenesis of SAP complicated by lung injury and related studies in order to provide the theoretical basis for its effective prevention and treatment.

Cholecystokinin activates pancreatic calcineurin-NFAT signaling in vitro and in vivo

Elevated endogenous cholecystokinin (CCK) release induced by protease inhibitors leads to pancreatic growth. This response has been shown to be mediated by the phosphatase calcineurin, but its downstream effectors are unknown. Here we examined activation of calcineurin-regulated nuclear factor of activated T-cells (NFATs) in isolated acinar cells, as well as in an in vivo model of pancreatic growth. Western blotting of endogenous NFATs and confocal imaging of NFATc1-GFP in pancreatic acini showed that CCK dose-dependently stimulated NFAT translocation from the cytoplasm to the nucleus within 0.5-1 h. This shift in localization correlated with CCK-induced activation of NFAT-driven luciferase reporter and was similar to that induced by a calcium ionophore and constitutively active calcineurin. The effect of CCK was dependent on calcineurin, as these changes were blocked by immunosuppressants FK506 and CsA and by overexpression of the endogenous protein inhibitor CAIN. Parallel NFAT activation took place in vivo. Pancreatic growth was accompanied by an increase in nuclear NFATs and subsequent elevation in expression of NFAT-luciferase in the pancreas, but not in organs unresponsive to CCK. The changes also required calcineurin, as they were blocked by FK506. We conclude that CCK activates NFATs in a calcineurin-dependent manner, both in vitro and in vivo.

Effects of large dose of dexamethasone on inflammatory mediators and pancreatic cell apoptosis of rats with severe acute pancreatitis

AIM: To investigate the influence of high dose of dexamethasone on inflammatory mediators and apoptosis of rats with severe acute pancreatitis (SAP).

METHODS: SAP rats were randomly assigned to the model group and treatment group while the normal rats were assigned to the sham operation group. The mortality, ascite volumes, ascites/body weight ratio and pancreas pathological changes of all rats were observed at 3, 6 and 12 h after operation. Their contents of amylase and endotoxin in plasma and contents of tumor necrosis factor (TNF-α), phospholipase A₂ (PLA₂) and IL-6 in serum were also determined. The microarray sections of their pancreatic tissues were prepared, terminal transferase dUTP nick end labeling (TUNEL) staining was performed and apoptotic indexes were calculated.

RESULTS: There was no marked difference between treatment group and model group in survival. The contents of amylase and endotoxin in plasma and contents of TNF-α, PLA₂ and IL-6 in serum, ascite volumes, ascites/body weight ratio and pancreas pathological scores were all lower in treatment group than in model group to different extents at different time points [P < 0.05, 58.3 (26.4) ng/L vs 77.535 (42.157) ng/L in TNF-α content, 8.00 (2.00) points vs 9.00 (2.00) points in pathological score of pancreas respectively; P < 0.01, 0.042 (0.018) EU/mL vs 0.056 (0.0195) EU/mL in endotoxin content, 7791 (1863) U/L vs 9195 (1298) U/L in plasma amylase content, 1.53 (0.79) vs 2.38 (1.10) in ascites/body weight ratio, 8.00 (1.00) points vs 11.00 (1.50) points in pathological score of pancreas; P < 0.001, 3.36 (1.56) ng/L vs 5.65 (1.08) ng/L in IL-6 content, 4.50 (2.00) vs 7.20 (2.00), 4.20 (1.60) vs 6.40 (2.30), 3.40 (2.70) vs 7.90 (1.70) in ascite volumes, respectively]. The apoptotic indexes of pancreas head and pancreas tail were all higher in treatment group than in model group at 6 h [P < 0.01, 0.00 (2.00)% vs 0.00 (0.00)%, 0.20 (1.80) vs 0.00 (0.00) in apoptosis indexes, respectively].

CONCLUSION: The mechanism of dexamethasone treatment in acute pancreatitis is related to its inhibition of inflammatory mediator generation and induction of pancreatic acinar cell apoptosis.

Abdominal Pain

Evaluation of the elderly patient with acute abdominal pain is sometimes difficult. Various factors can obscure the presentation, delaying or preventing the correct diagnosis and leading to adverse patient outcomes. Clinicians must consider multiple diagnoses, especially those life-threatening conditions that require timely intervention to limit morbidity and mortality. This article reviews abdominal pain in the elderly, discusses the clinical approach, and highlights key diagnostic considerations.

The pancreatic stellate cell: a star on the rise in pancreatic diseases

Pancreatic stellate cells (PaSCs) are myofibroblast-like cells found in the areas of the pancreas that have exocrine function. PaSCs are regulated by autocrine and paracrine stimuli and share many features with their hepatic counterparts, studies of which have helped further our understanding of PaSC biology. Activation of PaSCs induces them to proliferate, to migrate to sites of tissue damage, to contract and possibly phagocytose, and to synthesize ECM components to promote tissue repair. Sustained activation of PaSCs has an increasingly appreciated role in the fibrosis that is associated with chronic pancreatitis and with pancreatic cancer. Therefore, understanding the biology of PaSCs offers potential therapeutic targets for the treatment and prevention of these diseases.

Existence of autocrine loop between interleukin-6 and transforming growth factor-beta1 in activated rat pancreatic stellate cells

Interleukin (IL)-6 is a proinflammatory cytokine assumed to participate in pancreatic fibrosis by activating pancreatic stellate cells (PSCs). Autocrine TGF-beta1 is to central in PSC functional regulation. In this study, we examined IL-6 secretion from culture-activated rat PSCs and its regulatory mechanism. Activated PSCs express and secrete IL-6. When anti-TGF-beta1 neutralizing antibody was added in the culture medium, IL-6 secretion from activated PSCs was inhibited, whereas exogenous TGF-beta1 added in the culture medium enhanced IL-6 expression and secretion by PSCs in a dose dependent manner. Infection of PSCs with an adenovirus expressing dominant-negative Smad2/3 attenuated basal and TGF-beta1-stimulated IL-6 expression and secretion of PSCs. We also demonstrated the reciprocal effect of PSCs-secreted IL-6 on autocrine TGF-beta1. Anti-IL-6 neutralizing antibody inhibited TGF-beta1 secretion from PSCs. Preincubation of cells with 10 nM PD98059, an extracellular signal-regulated kinase (ERK)-dependent pathway inhibitor, attenuated IL-6-enhanced TGF-beta1 expression and secretion of PSCs. In addition, IL-6 activated ERK in PSCs. These data indicate the existence of autocrine loop between IL-6 and TGF-beta1 through ERK- and Smad2/3-dependent pathways in activated PSCs.

Pancreas recovery following cerulein-induced pancreatitis is impaired in plasminogen-deficient mice

BACKGROUND & AIMS

The plasminogen (plg) system participates in tissue repair in several organs, but its role in pancreas repair remains poorly characterized. To understand better the role of plg in pancreas recovery following injury, we examined the course of cerulein-induced pancreatitis in plg-deficient and -sufficient mice.

METHODS

Pancreatitis was induced by cerulein administration (50 microg/kg, 7 intraperitoneal injections). Mice were killed either at the acute phase (7 hours after the first cerulein injection) or during recovery (at 2, 4, and 7 days). In pancreatic sections, we examined pancreatic morphology, trypsin activation, inflammatory cell infiltration, acinar cell death, cell proliferation, extracellular matrix deposition, activation of stellate cells (PSCs), and components of the plg and metalloproteinase systems.

RESULTS

In plg-sufficient mice, pancreatic plg levels and plasmin activity increased during the acute phase and remained elevated during recovery. Pancreatitis resolved in plg-sufficient mice within 7 days. Pancreas recovery involved reorganization of the parenchyma structure, removal of necrotic debris, cell proliferation, transient activation of PSCs, and moderate deposition of extracellular matrix proteins. Acute pancreatitis (7 hours) was indistinguishable between plg-deficient and -sufficient mice. In contrast, pancreas recovery was impaired in plg-deficient mice. Plg deficiency led to disorganized parenchyma, extensive acinar cell loss, poor removal of necrotic debris, reduced cell proliferation, and fibrosis. Fibrosis was characterized by deposition of collagens and fibronectin, persistent activation of PSCs, and up-regulation of pancreatic transforming growth factor beta1.

CONCLUSIONS

Plg/plasmin deficiency leads to features similar to those found in chronic pancreatitis such as parenchymal atrophy and fibrosis.

Cyclooxygenase-2 is required for activated pancreatic stellate cells to respond to proinflammatory cytokines

Cyclooxygenase-2 (COX-2) mediates various inflammatory responses and is expressed in pancreatic tissue from patients with chronic pancreatitis. To examine the role of COX-2 in chronic pancreatitis, we investigated its participation in regulating functions of pancreatic stellate cells (PSCs), using isolated rat PSCs. COX-2 was expressed in culture-activated PSCs but not in freshly isolated quiescent PSCs. TGF-beta1, IL-1beta, and IL-6 enhanced COX-2 expression in activated PSCs, concomitantly increasing the expression of alpha-smooth muscle actin (alpha-SMA), a parameter of PSC activation. The COX-2 inhibitor NS-398 blocked culture activation of freshly isolated quiescent PSCs. NS-398 also inhibited the enhancement of alpha-SMA expression by TGF-beta1, IL-1beta, and IL-6 in activated PSCs. These data indicate that COX-2 is required for the initiation and promotion of PSC activation. We further investigated the mechanism by which cytokines enhance COX-2 expression in PSCs. Adenovirus-mediated expression of dominant negative Smad2/3 inhibited the increase in expression of COX-2, alpha-SMA, and collagen-1 mediated by TGF-beta1 in activated PSCs. Moreover, dominant negative Smad2/3 expression attenuated the expression of COX-2 and alpha-SMA enhanced by IL-1beta and IL-6. Anti-TGF-beta neutralizing antibody also attenuated the increase in COX-2 and alpha-SMA expression caused by IL-1beta and IL-6. IL-6 as well as IL-1beta enhanced TGF-beta1 secretion from PSCs. These data indicate that Smad2/3-dependent pathway plays a central role in COX-2 induction by TGF-beta1, IL-1beta, and IL-6. Furthermore, IL-1beta and IL-6 promote PSC activation by enhancing COX-2 expression indirectly through Smad2/3-dependent pathway by increasing TGF-beta1 secretion from PSCs.

Autocrine loop between TGF-beta1 and IL-1beta through Smad3- and ERK-dependent pathways in rat pancreatic stellate cells

Pancreatic stellate cells (PSCs) are activated during pancreatitis and promote pancreatic fibrosis by producing and secreting ECMs such as collagen and fibronectin. IL-1beta has been assumed to participate in pancreatic fibrosis by activating PSCs. Activated PSCs secrete various cytokines that regulate PSC function. In this study, we have examined IL-1beta secretion from culture-activated PSCs as well as its regulatory mechanism. RT-PCR and ELISA have demonstrated that PSCs express IL-1beta mRNA and secrete IL-1beta peptide. Inhibition of TGF-beta(1) activity secreted from PSCs by TGF-beta(1)-neutralizing antibody attenuated IL-1beta secretion from PSCs. Exogenous TGF-beta(1) increased IL-1beta expression and secretion by PSCs in a dose-dependent manner. Adenovirus-mediated expression of dominant-negative (dn)Smad2/3 expression reduced both basal and TGF-beta(1)-stimulated IL-1beta expression and secretion by PSCs. Coexpression of Smad3 with dnSmad2/3 restored IL-1beta expression and secretion by PSCs, which were attenuated by dnSmad2/3 expression. In contrast, coexpression of Smad2 with dnSmad2/3 did not alter them. Furthermore, inhibition of IL-1beta activity secreted from PSCs by IL-1beta-neutralizing antibody attenuated TGF-beta(1) secretion from PSCs. Exogenous IL-1beta enhanced TGF-beta(1) expression and secretion by PSCs. IL-1beta activated ERK, and PD-98059, a MEK1 inhibitor, blocked IL-1beta enhancement of TGF-beta(1) expression and secretion by PSCs. We propose that an autocrine loop exists between TGF-beta(1) and IL-1beta in activated PSCs through Smad3- and ERK-dependent pathways.

Recapitulation of elements of embryonic development in adult mouse pancreatic regeneration

BACKGROUND & AIMS

The mammalian pancreas has a strong regenerative potential, but the origin of organ restoration is not clear, and it is not known to what degree such a process reflects pancreatic development. To define cell differentiation changes associated with pancreatic regeneration in adult mice, we compared regeneration following caerulein-induced pancreatitis to that of normal pancreatic development.

METHODS

By performing comparative histology for adult and embryonic pancreatic markers in caerulein-treated and control pancreas, we addressed cellular proliferation and differentiation (amylase, DBA-agglutinin, insulin, glucagon, beta-catenin, E-cadherin, Pdx1, Nkx6.1, Notch1, Notch2, Jagged1, Jagged2, Hes1), hereby describing the kinetics of tissue restoration.

RESULTS

We demonstrate that surviving pancreatic exocrine cells repress the terminal exocrine gene program and induce genes normally associated with undifferentiated pancreatic progenitor cells such as Pdx1, E-cadherin, beta-catenin, and Notch components, including Notch1 , Notch2 , and Jagged2 . Expression of the Notch target gene Hes1 provides evidence that Notch signaling is reactivated in dedifferentiated pancreatic cells. Although previous studies have suggested a process of acino-to-ductal transdifferentiation in pancreatic regeneration, we find no evidence to suggest that dedifferentiated cells acquire a ductal fate during this process.

CONCLUSIONS

Pancreatic regeneration following chemically induced pancreatitis in the mouse occurs predominantly through acinar cell dedifferentiation, whereby a genetic program resembling embryonic pancreatic precursors is reinstated.

Expression of TREM-1 mRNA in acute pancreatitis

AIM: To explore the expression of triggering receptor expressed on myeloid cells (TREM-1) mRNA in acute pancreatitis (AP).

METHODS: Using the reverse transcription polymerase chain reaction (RT-PCR), we examined the expression of TREM-1 mRNA in 10 cases of mild acute pancreatitis (MAP), 8 cases of severe acute pancreatitis (SAP), and 10 cases of healthy control subjects. And we also examined the expression of TREM-1 mRNA in 14 cases of AP (including 10 MAP and 4 SAP) before treatment, after successful therapy and clinically cured.

RESULTS: The expression of TREM-1 mRNA in the groups of MAP, SAP patients and healthy control subjects was 0.771 ± 0.274, 1.092 ± 0.331 and 0.459 ± 0.175, respectively; there was a significant difference among the three groups (P < 0.05). And there was also a significant difference between the AP patients (0.914 ± 0.341) and healthy control subjects (0.459 ± 0.175) (P < 0.05). Moreover, in the 14 cases of AP, before treatment, after successful therapy and clinically cured, the expression of TREM-1 mRNA was 0.905 ± 0.226, 0.739 ± 0.169 and 0.633 ± 0.140, respectively, and there was a significant difference among the three stages (P < 0.05).

CONCLUSION: The expression of TREM-1 mRNA in the patients with AP increases obviously, and correlates with the degree of AP. Furthermore, the expression of TREM-1 mRNA is distinctly different at the different stages of AP. It indicates TREM-1 may play an important role in the occurrence and development of AP.