New perspectives on acute pancreatitis

Lutein inhibits IL‑6 expression by inducing PPAR‑γ activation and SOCS3 expression in cerulein‑stimulated pancreatic acinar cells

Acute pancreatitis is a severe inflammatory disease of the pancreas. In experimental acute pancreatitis, cerulein induces the expression of interleukin-6 (IL-6) by activating Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 3 in pancreatic acinar cells. Ligands of peroxisome proliferator activated receptor-γ (PPAR-γ) and suppressor of cytokine signaling (SOCS) 3 inhibit IL-6 expression by suppressing JAK2/STAT3 in cerulein-stimulated pancreatic acinar AR42J cells. Lutein, an oxygenated carotenoid, upregulates and activates PPAR-γ to regulate inflammation in a renal injury model. The present study aimed to determine whether lutein activated PPAR-γ and induced SOCS3 expression in unstimulated AR42J cells, and whether lutein inhibited activation of JAK2/STAT3 and IL-6 expression via activation of PPAR-γ and SOCS3 expression in cerulein-stimulated AR42J cells. The anti-inflammatory mechanism of lutein was determined using reverse transcription-quantitative PCR, western blot analysis and enzyme-linked immunosorbent assay in AR42J cells stimulated with or without cerulein. In another experiment, cells were treated with lutein and the PPAR-γ antagonist GW9662 or the PPAR-γ agonist troglitazone prior to cerulein stimulation to determine the involvement of PPAR-γ activation. The results indicated that lutein increased PPAR-γ and SOCS3 levels in unstimulated cells. Cerulein increased phospho-specific forms of JAK2 and STAT3, and mRNA and protein expression of IL-6, but decreased SOCS3 levels in AR42J cells. Cerulein-induced alterations were suppressed by lutein or troglitazone. GW9662 alleviated the inhibitory effect of lutein on JAK2/STAT3 activation and IL-6 expression in cerulein-stimulated cells. In conclusion, lutein inhibited the activation of JAK2/STAT3 and reduced IL-6 levels via PPAR-γ-mediated SOCS3 expression in pancreatic acinar cells stimulated with cerulein.

Resveratrol suppresses microcirculatory disturbance in a rat model of severe acute pancreatitis

The present study sought to understand the mechanisms of attenuation of severe acute pancreatitis (SAP) by resveratrol (RES). SAP was experimentally induced in rats by injection of 4% sodium taurocholate in the retrograde pancreatic duct. Three study groups were evaluated: Group I (sham-operated animals), Group II (SAP animals), and Group III (SAP animals treated with RES at 20 mg/kg/body weight, 5 min after induction of SAP). The study outcomes were histopathologic changes and alterations in biochemical markers: plasma renin activity and levels of angiotensin II, endothelin, and nitric oxide in plasma. Biochemical markers were evaluated at 3, 6, and 12 h after induction of SAP. SAP was associated with significant (p < 0.05) histopathologic changes (saponification spots in the intraperitoneal cavity, severe pancreatic edema, blood congestion, varying degrees of necrosis, etc.), as well as with elevation of biochemical markers in blood plasma. RES treatment significantly (p < 0.05) attenuated changes of both histopathologic and biochemical markers induced by SAP. In conclusion, this study provides evidence that RES treatment is a promising therapeutic approach to suppress microcirculatory disturbance in SAP.

Effect of interferon-γ on NF-κB and cytokine IL-18 and IL-27 in acute pancreatitis

The objective of our work was to evaluate the effect of interferon-γ (IFN-γ) on cytokine expression in rat acute pancreatitis (AP). AP was introduced to rats which were divided into Control, AP and IFN-γ group. Rats in the AP and IFN-γ group were sacrificed as 6, 12 and 24 h after IFN-γ treatment. The serum amylase (AMA), endotoxin and cytokines were detected. The pathological examination and immunofluorescence staining of pancreas for TNF-α, NF-κB and IL-18 were performed. The serum AMA increased significantly at 6 h and reduced at 48 h after AP. The increase in IFN-γ was higher than that in AMA. IL-18 increased in the AP and IFN group, and IFN increased markedly at 48 h after AP. IL-27 reduced at 24 h after AP compared with AP group. In the AP group, the immunostaining of cytokines increased. In the IFN group, the edema in the pancreas was more severe, and NF-κB and IL-18 expression was higher than that in the other two groups. IFN-γ can increase serum IL-18 and reduce IL-27 in AP. IFN-γ can increase serum IL-18 and reduce serum IL-27 in AP. The increase in NF-κB and IL-18 may exert influence on pro-inflammatory cytokines to deteriorate inflammation in the pancreas. Thus, to control the IFN-γ might has promise to attenuate pancreatitis.

Oxymatrine ameliorates L-arginine-induced acute pancreatitis in rats

The aim of this study was to determine whether oxymatrine has a protective effect against acute pancreatitis (AP) in a rat model of L-arginine-induced AP. AP was induced by two intraperitoneal injections of L-arginine (250 mg/100 g) at a 1-h interval. Oxymatrine (50 mg/kg) was administered every 6 h after the induction of AP. Oxymatrine significantly reduced the plasma amylase, D-lactic acid and tumor necrosis factor alpha concentration, serum diamine oxidase and lipase activity, and pancreatic myeloperoxidase activity, which were increased in AP rats (P < 0.05). In addition, the pancreatic CD45 expression and the expression of claudin-1, but not zonula occludens-1 (ZO-1) and occludin, in the intestinal tissues were significantly reduced after the induction of AP. However, oxymatrine increased the expression of claudin-1 and CD45, but did not alter the expression of ZO-1 and occludin. In conclusion, our results demonstrated that oxymatrine is potentially capably of protecting against L-arginine-induced AP and attenuating AP-associated intestinal barrier injury by up-regulation of claudin-1.

Ethyl pyruvate improves survival and ameliorates distant organ injury in rats with severe acute pancreatitis

OBJECTIVE

To evaluate the effect of ethyl pyruvate (EP) in improving the survival and ameliorating distant organ damage and to investigate the role of high-mobility group box (HMGB) 1 in rats with established severe acute pancreatitis (SAP).

METHODS

Severe acute pancreatitis was induced by retrograde infusion of sodium taurodeoxycholate (5%, 1 mL/kg) into the biliopancreatic ducts in male Wistar rats. The rats were infused intravenously with EP of 40 mg/kg, 4 mg/kg, and 0.4 mg/kg initiating 12 hours, and EP of 40 mg/kg was administered beginning 2 hours before surgery (-2 hours) and 12, 24, and 36 hours after induction of SAP; then, the mortality was recorded. Serum tumor necrosis factor alpha, interleukin (IL) 6, and IL-1beta were measured using enzyme-linked immunosorbent assay. High-mobility group box 1 levels were measured using Western immunoblotting analysis.

RESULTS

Serum HMGB1 levels were increased dramatically after 12 hours, remained at high levels for 72 hours, and were significantly higher in rats with SAP than in those with mild and moderate pancreatitis (P < 0.01). Treatment with EP (40 mg/kg) conferred protection from lethality of SAP (EP survival [63%] vs vehicle survival [6.3%]; P < 0.001). No survival advantage occurred when treatment was initiated 36 hours after surgery, but administration beginning 2 hours before operation (-2 hours) and 12 and 24 hours after induction of SAP significantly increased survival. Ethyl pyruvate treatment significantly decreased serum HMGB1, tumor necrosis factor alpha, IL-1beta, and IL-6 levels and ameliorated extrapancreatic organ dysfunction in rats with SAP.

CONCLUSIONS

Ethyl pyruvate improves survival and ameliorates distant organ injury of SAP. These beneficial effects of EP are because of the modulation of HMGB1 and other inflammatory cytokine responses.

Cytokines (IL-6, IL-8, TNF): early and reliable predictors of severe acute pancreatitis

BACKGROUND

Severe acute pancreatitis is associated with a high mortality, especially when compared with mild acute pancreatitis. Early intervention in patients with severe acute pancreatitis has been shown to improve mortality. The value of cytokines (interleukin [IL]-6, IL-8 and tumor necrosis factor [TNF]-alpha) in diagnosing severe acute pancreatitis at an early stage was studied.

STUDY

Thirty-six patients with acute pancreatitis were prospectively evaluated. Age-matched controls were obtained from healthy volunteers. Levels of IL-6, IL-8, and TNF-alpha were obtained within 24 hours of admission. Ranson's prognostic signs and Bank's clinical criteria were used to differentiate patients into mild and severe pancreatitis.

RESULTS

There was significant difference in IL-6 levels between controls and mild pancreatitis, controls and severe pancreatitis, and mild and severe pancreatitis. IL-8 levels were significantly different between controls and severe pancreatitis and mild and severe pancreatitis. There was no significant difference between controls and mild pancreatitis. The results for TNF-alpha were similar to the findings for IL-8.

CONCLUSION

IL-6, IL-8, and TNF can be used independently in differentiating mild acute pancreatitis from early severe acute pancreatitis.

A glyconutritional mixture (Ambrotose®) provides some amelioration to mice with coxsackievirus-induced pancreatitis

Challenge of adolescent male CD-1 mice with a coxsackievirus B3 (CVB3) strain (CVB3m) induces mild to severe destruction of pancreatic acinar cells, but causes no deaths and does not induce hyperglycemia. A weekly parenteral (intraperitoneal) administration of a glyconutritional mixture (Ambrotose® to virus-challenged mice was assessed to determine if there were any benefits to recovery over an eight month period. Virus-challenged mice showed a significant weight loss over the initial five weeks of the experiment, but injection of Ambrotose® to similar virus-challenged mice restored the total body weight to levels found in normal mice. Normal mice given Ambrotose® exhibited a small weight gain. Mice given Ambrotose® showed reduced severity of pancreatitis, as evidenced by significant reductions in percentages of pancreatic acinar cells destroyed and proportion of sections of pancreata with destroyed acinar cells, compared to virus control-mice not injected with Ambrotose®. Statistical analyses of the extent of acinar cell pathology in all virus-challenged mice showed that Ambrotose® contributed significantly to recovery of the acinar cell population in virus-inoculated mice. Anti-viral antibody titers were not affected by Ambrotose® injections. One potential mechanism to explain the benefits derived from Ambrotose® injections came from studies of antioxidant levels of glutathione in splenic macrophages/monocytes. Whereas CVB3 challenge of mice reduced glutathione levels in the latter cells, Ambrotose® injections to virus-challenged mice restored glutathione levels to those found in normal mice. In summary, most but not all mice derived benefits from Ambrotose® injections, i.e. a reduction in pathology in the pancreas and restored levels of the antioxidant glutathione in macrophages/monocytes. Higher doses of Ambrotose® could provide greater benefits for more mice, a study for the future.

The role of cytokines in the pathogenesis of acute pancreatitis

BACKGROUND

The systemic manifestations of acute pancreatitis are responsible for the majority of pancreatitis-associated morbidity and mortality and are now believed to be due to the actions of specific inflammatory cytokines. This report summarizes what is known about the role of cytokines in the pathogenesis of acute pancreatitis.

METHODS

Comprehensive literature review of experimental pancreatitis as well as all reports of cytokine involvement during clinical pancreatitis.

RESULTS

Several cytokines and other noncytokine inflammatory mediators are produced rapidly during pancreatitis. These mediators arise in many tissues in a predictable fashion independent of the animal model used or the underlying etiology in human disease. Preventing the activities of these mediators has a profound beneficial effect in experimental animals.

CONCLUSIONS

A few recently described inflammatory mediators are believed to be primarily responsible for the systemic manifestations of acute pancreatitis and its associated distant organ dysfunction. The predictable nature in which they are produced may allow for novel approaches to treating this disease. Am J Surg.

Clinical update: management of acute pancreatitis

The management of acute pancreatitis commences with confirming the diagnosis and establishing the aetiology. Improved methods of assessing the biliary tree may reduce the number of patients regarded as having idiopathic pancreatitis. Detailed clinical and laboratory protocols, designed to assess severity, have no major advantage over clinical assessment. The contrast-enhanced computed tomography scan is important to assess the degree of pancreatic necrosis and to detect local complications. The treatment of pancreatitis continues to be largely supportive. However, controlled studies support the use of antibiotics in severe acute pancreatitis and indicate a possible role for the use of octreotide and antioxidants. The place of endoscopic and surgical intervention is becoming better defined. Once an attack has passed, further investigation is often required in a bid to prevent further episodes of inflammation.

Infusion of C1-inhibitor plasma concentrate prevents hyperamylasemia induced by endoscopic sphincterotomy

Hyperamylasemia after endoscopic sphincterotomy is a common event, occurring in about 70% of cases. Clinical acute pancreatitis may also develop in 1% to 6% of cases. Previous attempts to prevent this reaction with inhibitors of exocrine pancreatic secretion (somatostatin and octreotide) provided conflicting and often disappointing results. Kallikrein is one of the proteases that sustain the inflammatory process in acute pancreatitis; the C1 inhibitor is the only physiologic inhibitor of the first component of the human complement cascade and is a major inactivator of kallikrein and Factor XII. Therefore, we tested the C1 inhibitor in the prevention of hyperamylasemia in 40 consecutive patients undergoing endoscopic sphincterotomy for common bile duct stones or benign papillary stenosis. They were given either C1 inhibitor (20 cases) or placebo (20 cases) before the procedure. Serum amylase levels were determined at baseline and 2, 4, 8, and 24 hours thereafter. Significant differences in serum amylase levels between groups were observed at 2 hours (p < .01), 4 hours (p < .0005), and 8 hours (p < .005) after sphincterotomy. The differences in amylase levels were also significant among the 24 subjects with pancreatic ductal filling (2 hours, p < .05; 4 hours, p < .005; 8 hours, p < .01) and the 9 patients with previous episodes of acute pancreatitis (4 hours, p < .05; 8 hours, p < .05; 24 hours, p < .05). The infusion of C1-inhibitor plasma concentrate resulted in a 50% increase in functional levels of C1 inhibitor (in the 8 cases for whom they were assayed), which persisted throughout the observation period.

The lysosomal hydrolases in the rat pancreas after maximal or supramaximal stimulation with cerulein

The decompartmentation of lysosomal compartment in pancreatic acinar cells with consecutive activation of zymogens might play an important role as a "trigger mechanism" in acute pancreatitis. The admixture of lysosomal hydrolases to secretory enzymes in pancreatic juice was found, but their role in pancreatic secretion remains obscure. The aim of the present study was to assess the fragility of pancreatic lysosomal structure after maximal (optimal) or supramaximal stimulation of rats with cerulein during 3, 6, 12 h, and after recovery. In the mitochondrial-lysosomal (M-L) and in the supernatant (S) of pancreases free (F) total (T), and fractional free (%F/T) activities of beta-glucuronidase (beta G), acid phosphatase (AcP), cathepsins (Cs), and beta-N-acetyl-hexosaminidase (NAH) were estimated. In edematous pancreatitis following supramaximal stimulation with cerulein, a significant increase of %F/T of beta G in whole homogenate began at 6 h of hyperstimulation in comparison to the control (93 vs 42% p < 0.01). This increment persisted until 12 h of hyperstimulation and declined after 24 and 48 h of recovery to 67-69%. The changes of %F/T of beta G in M-L followed those in whole homogenate, and additionally the increase free activity in S after 6 h of hyperstimulation and after 24 h recovery occurred. The respective activities of other hydrolases showed a similar pattern of changes. It is of interest that fragility of lysosomal membranes increases significantly also after maximal stimulation when inflammatory changes were absent. Our results suggest that the increase of lysosomal fragility of the pancreas is most unlikely pathological in itself, but also occurs during stimulated pancreatic secretion.(ABSTRACT TRUNCATED AT 250 WORDS)