Colonic mucin-2 attenuates acute necrotizing pancreatitis in rats by modulating intestinal homeostasis.

Mucin-2 (MUC2) secreted by goblet cells participates in the intestinal barrier, but its mechanism in acute necrotizing pancreatitis (ANP) remains unclear. In acute pancreatitis (AP) patients, the functions of goblet cells (MUC2, FCGBP, CLCA1, and TFF3) decreased, and MUC2 was negatively correlated with AP severity. ANP rats treated with pilocarpine (PILO) (PILO+ANP rats) to deplete MUC2 showed more serious pancreatic and colonic injuries, goblet cell dysfunction, gut dysbiosis, and bacterial translocation than those of ANP rats. GC-MS analysis of feces showed that PILO+ANP rats had lower levels of butyric acid, isobutyric acid, isovaleric acid, and hexanoic acid than those of ANP rats. The expression of MUC2 was associated with colonic injury and gut dysbiosis. All these phenomena could be relieved, and goblet cell functions were also partially reversed by MUC2 supplementation in ANP rats. TNF-α-treated colonoids had exacerbated goblet cell dysfunction. MUC2 expression was negatively correlated with the levels of pro-inflammatory cytokines (IL-1ß and IL-6) (p < .05) and positively related to the expression of tight junction proteins (Claudin 1, Occludin, and ZO1) (p < .05). Downregulating MUC2 by siRNA increased the levels of the pro-inflammatory cytokines in colonoids. MUC2 might maintain intestinal homeostasis to alleviate ANP.

Vitamin E protects against the modulation of TNF-α-AMPK axis and inhibits pancreas injury in a rat model of L-arginine-induced acute necrotising pancreatitis.

BACKGROUND: Acute pancreatitis (AP) associated with the modulation of TNF-α-AMPK axis in the presence and absence of vitamin E has not been investigated before. MATERIAL AND METHODS: Rats were either injected with L-arginine (2.5 gm/kg) before being sacrificed after 48 h or were pre-treated with vitamin E (60 mg/kg) and continued receiving vitamin E until the end of the experiment. RESULTS: AP was developed as demonstrated by infiltration of inflammatory cells and profound pancreas tissue damage, which were substantially protected by vitamin E. In addition, L-arginine injections significantly (p < .0001) increased the expression of TNF-α mRNA and protein, and decreased phospho-AMPK and IL-10 mRNA and protein that was significantly (p < .0001) protected by vitamin E. Furthermore, vitamin E inhibited L-arginine-induced blood levels of LDH, amylase, and myeloperoxidase. CONCLUSIONS: L-arginine-induced acute pancreatitis modulates TNF-α-AMPK axis, IL-10 and other AP biomarkers, which is protected by vitamin E; thus, may offer therapeutic potential in humans.

Effect of TRAF6 in acute pancreatitis-induced intestinal barrier injury via TLR4/NF-κB signal pathway.

BACKGROUND: The aim of this study was to investigate the effect of tumor necrosis factor receptor-related factor 6 (TRAF6) in acute pancreatitis (AP)-induced intestinal barrier injury via the Toll-like receptor 4/nuclear factor kappa-B (TLR4/NF-κB) signal pathway. METHODS: Rat models of acute edematous pancreatitis (AEP) and acute necrotizing pancreatitis (ANP) were established by intraperitoneal injection of caerulein and retrograde infusion of sodium taurocholate solution into the biliopancreatic duct, respectively. Separate groups of model rats were pretreated with the TRAF6 inhibitor, MG-132. Rats were sacrificed at 12 h after the last injection for inducing AP. Histopathological changes, inflammatory response, intestinal barrier function, and protein expression levels were assessed by pathological score, ELISA, TUNEL, qRT-PCR, immunohistochemistry and western blotting. RESULTS: Rat models of AEP and ANP were successfully established as evidenced by the pathological changes in the pancreas and intestine. Pre-treatment with MG-132 significantly alleviated pancreatic and intestinal pathological scores, reduced serum levels of amylase, IL-1ß, and IL-6, and ameliorated apoptosis of mucosal cells. MG-132 reduced intestinal barrier injury, including serum levels of diamine oxidase and lipopolysaccharide, and intestinal expressions of ZO-1 and occludin. Moreover, it significantly suppressed the activation of the intestinal TLR4/NF-κB signaling pathway. CONCLUSIONS: TRAF6 inhibitor alleviated pancreatic and intestinal injury in AEP and ANP. This effect may be mediated through inhibition of the TLR4/NF-κB signaling pathway, which in turn regulates the inflammatory response and intestinal barrier injury.

Fentanyl but Not Morphine or Buprenorphine Improves the Severity of Necrotizing Acute Pancreatitis in Rats.

Opioids are widely used for the pain management of acute pancreatitis (AP), but their impact on disease progression is unclear. Therefore, our aim was to study the effects of clinically relevant opioids on the severity of experimental AP. Various doses of fentanyl, morphine, or buprenorphine were administered as pre- and/or post-treatments in rats. Necrotizing AP was induced by the intraperitoneal injection of L-ornithine-HCl or intra-ductal injection of Na-taurocholate, while intraperitoneal caerulein administration caused edematous AP. Disease severity was determined by laboratory and histological measurements. Mu opioid receptor (MOR) expression and function was assessed in control and AP animals. MOR was expressed in both the pancreas and brain. The pancreatic expression and function of MOR were reduced in AP. Fentanyl post-treatment reduced necrotizing AP severity, whereas pre-treatment exacerbated it. Fentanyl did not affect the outcome of edematous AP. Morphine decreased vacuolization in edematous AP, while buprenorphine pre-treatment increased pancreatic edema during AP. The overall effects of morphine on disease severity were negligible. In conclusion, the type, dosing, administration route, and timing of opioid treatment can influence the effects of opioids on AP severity. Fentanyl post-treatment proved to be beneficial in AP. Clinical studies are needed to determine which opioids are best in AP.

Heparin-binding protein (HBP) worsens the severity of pancreatic necrosis via up-regulated M1 macrophages activation in acute pancreatitis mouse models.

Acute pancreatitis (AP) is one of the most widespread clinical emergencies. Macrophages are the most common immune cells in AP pancreatic tissue and are closely associated with pancreatic necrosis and recovery. The level of heparin-binding protein (HBP) is closely linked to inflammation. In this study, we assessed the effect of HBP on AP tissue necrosis severity and whether HBP is associated with M1 macrophages in pancreatic necrosis. We observed the dynamic changes of HBP levels in the pancreas during acute inflammation in the caerulein-induced AP mice model. We used hematoxylin-eosin staining to evaluate pancreatic edema and necrosis, and to detect infiltration of macrophages by immunohistochemistry. Moreover, expressions of the maker and cytokines of macrophages, including inducible nitric oxide synthase (iNOS), and arginase 1 (Arg-1), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) mRNA, were detected by real-time polymerase-chain reaction (RT-PCR). High levels of HBP in the pancreas were detected at 48 h, and heparin inhibited HBP expression in AP pancreatic tissue. Inhibiting HBP expression by injecting heparin before AP can alleviate pancreatic necrosis and inhibit F4/80 labeled M1 macrophage infiltration and IL-6, TNF-α, and iNOS mRNA expression. Clodronate liposome (CLDL) intraperitoneally treated mice showed no change in pancreatic HBP levels, but pancreatic macrophage-specific antigen F4/80 and TNF-α, IL-1ß, and IL-6 mRNA levels decreased after CLDL treatment. HBP is critical for pancreatic necrosis response in acute pancreatitis by increasing the infiltration of M1 macrophages and promoting the secretion of inflammatory factors, such as TNF-α, IL-6, IL-1ß, which can be reduced by heparin.

Inhibition of Notch activity promotes pancreatic cytokeratin 5-positive cell differentiation to beta cells and improves glucose homeostasis following acute pancreatitis.

Some individuals develop prediabetes and/or diabetes following acute pancreatitis (AP). AP-induced beta-cell injury and the limited regenerative capacity of beta cells might account for pancreatic endocrine insufficiency. Previously, we found that only a few pancreatic cytokeratin 5 positive (Krt5+) cells differentiated into beta cells in the murine AP model, which was insufficient to maintain glucose homeostasis. Notch signaling determines pancreatic progenitor differentiation in pancreas development. This study aimed to examine whether Notch signaling inhibition could promote pancreatic Krt5+ cell differentiation into beta cells and improve glucose homeostasis following AP. Pancreatic tissues from patients with acute necrotizing pancreatitis (ANP) were used to evaluate beta-cell injury, Krt5+ cell activation and differentiation, and Notch activity. The murine AP model was induced by cerulein, and the effect of Notch inhibition on Krt5+ cell differentiation was evaluated both in vivo and in vitro. The results demonstrated beta-cell loss in ANP patients and AP mice. Krt5+ cells were activated in ANP pancreases along with persistently elevated Notch activity, which resulted in the formation of massive duct-like structures. AP mice that received Notch inhibitor showed that impaired glucose tolerance was reversed 7 and 15 days following AP, and increased numbers of newborn small islets due to increased differentiation of Krt5+ cells to beta cells to some extent. In addition, Krt5+ cells isolated from AP mice showed increased differentiation to beta cells by Notch inhibition. Collectively, these findings suggest that beta-cell loss contributes to pancreatic endocrine insufficiency following AP, and inhibition of Notch activity promotes pancreatic Krt5+ cell differentiation to beta cells and improves glucose homeostasis. The findings from this study may shed light on the potential treatment of prediabetes/diabetes following AP.

RanBP2/Nup358 enhances miRNA activity by sumoylating Argonautes.

Mutations in RanBP2 (also known as Nup358), one of the main components of the cytoplasmic filaments of the nuclear pore complex, contribute to the overproduction of acute necrotizing encephalopathy (ANE1)-associated cytokines. Here we report that RanBP2 represses the translation of the interleukin 6 (IL6) mRNA, which encodes a cytokine that is aberrantly up-regulated in ANE1. Our data indicates that soon after its production, the IL6 messenger ribonucleoprotein (mRNP) recruits Argonautes bound to let-7 microRNA. After this mRNP is exported to the cytosol, RanBP2 sumoylates mRNP-associated Argonautes, thereby stabilizing them and enforcing mRNA silencing. Collectively, these results support a model whereby RanBP2 promotes an mRNP remodelling event that is critical for the miRNA-mediated suppression of clinically relevant mRNAs, such as IL6.

Elevated CA125 levels are associated with adverse clinical outcomes in acute pancreatitis: A propensity score-matched study.

OBJECTIVES: Glycosylation alterations are indicative of tissue inflammation and neoplasia. However, there are no large-sample, real-world studies assessing the levels of serum carbohydrate antigen 125 (CA125) in patients with acute pancreatitis (AP). We aimed to identify the association between elevated CA125 levels and adverse clinical outcomes in AP. METHODS: This was a retrospective cohort study with an analysis of 3939 patients with AP who were admitted to the First Affiliated Hospital of Nanchang University between January 2015 and September 2019 that used data from a prospectively maintained database. Multivariate logistic regression analysis and a propensity score-matched analysis were conducted to reveal the relationship between elevated CA125 levels and poor prognosis. RESULTS: The overall prevalence of elevated CA125 (>35 U/mL) levels was 38.51% (1517/3939) in AP patients. Elevated CA125 levels were independently associated with higher risks of mortality (adjusted odds ratio (AdjOR), 1.82; 95% confidence interval (CI), 1.30-2.54; P < 0.001), severe acute pancreatitis (SAP) (AdjOR, 2.40; 95% CI, 2.00-2.88; P < 0.001), and infected pancreatic necrosis (IPN) (AdjOR, 3.54; 95% CI, 2.65-4.71; P < 0.001). The propensity score-matched cohort analysis also demonstrated that mortality (OR, 1.57; 95% CI, 1.06-2.23; P < 0.05), SAP (OR, 2.20; 95% CI, 1.77-2.73; P < 0.001), and IPN (OR, 2.79; 95% CI, 1.98-3.92; P < 0.001) were more common in the elevated CA125 group than in the normal CA125 group. CONCLUSIONS: Elevated CA125 levels (>35 U/mL) are independently associated with adverse clinical outcomes in AP patients. These observations justify ongoing efforts to understand the role of CA125 in the pathogenesis and prognosis of AP.

Paneth Cell Ablation Aggravates Pancreatic and Intestinal Injuries in a Rat Model of Acute Necrotizing Pancreatitis after Normal and High-Fat Diet.

We previously reported that acute necrotizing pancreatitis (ANP) after normal or high-fat diet is associated with a decreased number of Paneth cells in ileal crypts. Here, we ablated Paneth cells in a rat model of ANP after normal and high-fat diet to investigate the effects on disease symptoms. Adult male Sprague-Dawley rats received standard rat chow or a high-fat diet for 2 weeks, after which they were treated with dithizone to deplete Paneth cells. Six hours later, ANP was established by retrograde injection of sodium taurocholate into the biliopancreatic duct. Rats were sacrificed at 6, 12, and 24 h for assessment. We found dithizone aggravated ANP-associated pathological injuries to the pancreas and ileum in rats on high-fat or standard diets. Lysozyme expression in ileal crypts was decreased, while serum inflammatory cytokines (TNFα, IL-1ß, and IL-17A) and intestinal permeability (serum DAO activity and D-lactate) were increased. Expression of tight junction proteins (claudin-1, zo-1, and occludin) was decreased. Using high-throughput 16S rRNA sequencing, we found dithizone reduced microbiota diversity and altered microbiota composition in rats on high-fat or standard diets. Dithizone decreased fecal short-chain fatty acids (SCFAs) in rats on high-fat or standard diets. Changes in intestinal microbiota correlated significantly with SCFAs, lysozyme, DAO activity, D-lactate, inflammatory cytokines, and pathological injury to the pancreas and ileum in rats on high-fat or standard diets. In conclusion, ablation of Paneth cells exacerbates pancreatic and intestinal injuries in ANP after normal and high-fat diet. These symptoms may be related to changes in the intestinal microbiota.

Bone marrow-derived mesenchymal stem cells alleviate severe acute pancreatitis-induced multiple-organ injury in rats via suppression of autophagy.

Patients with severe acute pancreatitis (SAP) represent a substantial challenge to medical practitioners due to the high associated rates of morbidity and mortality and a lack of satisfactory therapeutic outcomes. In a previous study, our group demonstrated that bone marrow-derived mesenchymal stem cells (BMSCs) can ameliorate SAP; however, the mechanisms of action remain to be fully understood. BMSCs were intravenously injected into SAP rats 12 h after experimental induction of SAP using sodium taurocholate (NaT). Histopathological changes and the levels of pro-inflammatory mediators were assessed by hematoxylin and eosin (H&E) staining and ELISA, respectively. Autophagy levels were assessed using qRT-PCR, western blotting, immunohistochemistry, immunofluorescence, and transmission electron microscopy. AR42J cells and human umbilical vein endothelial cells (HUVECs) were administered BMSC-conditioned media (BMSC-CM) after NaT treatment, and cell viability was measured using a Cell Counting Kit-8 (CCK-8) and flow cytometry. In vivo, BMSCs effectively reduced multiple systematic inflammatory responses, suppressed the activation of autophagy, and improved intestinal dysfunction. In vitro, BMSC-CM significantly improved the viability of injured cells, promoted angiogenesis, and decreased autophagy. We therefore propose that the administration of BMSCs alleviates SAP-induced multiple organ injury by inhibiting autophagy.

[Experimental study on the mechanism of glycogen synthase kinase-3ß inhibitor on acute kidney injury of acute necrotizing pancreatitis in rats].

OBJECTIVE: To explore the protective mechanism of glycogen synthase kinase-3ß (GSK-3ß) inhibitor TDZD-8 on acute necrotizing pancreatitis (ANP) associated kidney injury in rats. METHODS: SPF male Wistar rats were randomly divided into four groups (n = 20): sham operation group (Sham group), ANP model group, TDZD-8 intervention group and TDZD-8 control group. The rat ANP model was prepared by retrograde injection of 5% sodium taurocholate into the bile duct; the same volume of normal saline was injected into the pancreatic duct of the Sham group. The TDZD-8 intervention group and the TDZD-8 control group were injected with GSK-3ß inhibitor TDZD-8 (1 mL/kg) via the femoral vein 30 minutes before the model or sham operation; the ANP model group and the Sham group were injected equal volume of 10% dimethyl sulfoxide (DMSO). Rats in each group were sacrificed at 12 hours after operation to measure the serum amylase (AMY), blood lipase (LIPA), serum creatinine (SCr) and blood urea nitrogen (BUN) levels and to observe the pathological changes of pancreatic tissues and kidney tissues. Ultrastructural change of renal cells was analyzed by transmission electron microscopy. Serum interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) levels were evaluated by enzyme linked immunosorbent assay (ELISA). The activation of nuclear factor-ΚBp65 (NF-ΚBp65) was evaluated by immunohistochemistry assay. The protein expressions of GSK-3ß, phospho-GSK-3ß (Ser 9), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), intercellular adhesion molecule-1 (ICAM-1) and interleukin-10 (IL-10) in the kidney were determined by Western Blot. RESULTS: Compared with the Sham group, the serum and inflammatory factors levels of the ANP model group were significantly increased, the pathological damage of the pancreas and kidney tissues were severe, the histopathological score was significantly increased, the expression of NF-ΚBp65 was enhanced in the nucleus of the kidney tissue, and the expressions of GSK-3ß, TNF-α, ICAM-1 and iNOS were significantly enhanced, and the expressions of p-GSK-3ß(Ser 9) and IL-10 were significantly attenuated. Compared with the ANP model group, TDZD-8 pretreatment significantly reduced serum and inflammatory factor levels in the ANP model group [AMY (kU/L): 5.60±0.30 vs. 10.07±0.34, LIPA (U/L): 1 111.0±110.8 vs. 2 375.0±51.1, SCr (µmol/L): 47.38±1.48 vs. 72.50±2.43, BUN (mmol/L): 17.6±1.0 vs. 26.0±1.0, IL-1ß (ng/L): 195.90±5.50 vs. 332.40±38.29, IL-6 (ng/L): 246.10±26.74 vs. 385.30±32.19, all P < 0.01]; pathological damage of pancreas and kidney tissue (histopathological score: 7.1±0.4 vs. 12.1±0.3, 301.2±7.5 vs. 433.5±13.8, both P < 0.01) and ultrastructural damage of renal cells were alleviated; the expression of NF-ΚBp65 in the nucleus was significantly decreased; the expression of p-GSK-3ß (Ser 9) was significantly increased, and blocking GSK-3ß activity could inhibit the expressions of TNF-α, ICAM-1, iNOS and increase the expression of IL-10, while the expression of GSK-3ß in renal tissues was not statistically significant. There were no significant differences between the TDZD-8 control group and the Sham group. CONCLUSIONS: Blockade of GSK-3ß activity by TDZD-8 exerts the protective effect against kidney injury by inhibiting the inflammation signaling pathway in ANP. It can alleviate histopathological and ultrastructural changes in kidney injury, which protection mechanism is mediated by NF-ΚB and its related inflammatory mediators.

Murine Models of Acute Pancreatitis: A Critical Appraisal of Clinical Relevance.

Acute pancreatitis (AP) is a severe disease associated with high morbidity and mortality. Clinical studies can provide some data concerning the etiology, pathophysiology, and outcomes of this disease. However, the study of early events and new targeted therapies cannot be performed on humans due to ethical reasons. Experimental murine models can be used in the understanding of the pancreatic inflammation, because they are able to closely mimic the main features of human AP, namely their histologic glandular changes and distant organ failure. These models continue to be important research tools for the reproduction of the etiological, environmental, and genetic factors associated with the pathogenesis of this inflammatory pathology and the exploration of novel therapeutic options. This review provides an overview of several murine models of AP. Furthermore, special focus is made on the most frequently carried out models, the protocols used, and their advantages and limitations. Finally, examples are provided of the use of these models to improve knowledge of the mechanisms involved in the pathogenesis, identify new biomarkers of severity, and develop new targeted therapies.

High-mobility group box-1 inhibition stabilizes intestinal permeability through tight junctions in experimental acute necrotizing pancreatitis.

BACKGROUND: In acute necrotizing pancreatitis (ANP), bacterial translocation (BT) from the gastrointestinal tract is the essential pathogenesis in the development of septic complications. Although high-mobility group box-1 (HMGB1) is associated with BT and organ dysfunction in ANP, the mechanism of HMGB1 in the intestinal barrier dysfunction and BT has not been well addressed. In this study, we intend to address the role of HMGB1 in ANP involving BT and intestinal barrier dysfunction. METHODS: Experimental ANP was achieved in male Sprague-Dawley rats through a retrograde injection of taurocholate into the common biliopancreatic duct following a laparotomy operation. HMGB1 blockade intervention was conducted with a subcutaneous injection of anti-HMGB1 antibody immediately before the laparotomy procedure. Twenty-four hours after ANP induction, pancreatic and intestinal tissues and blood samples were collected for a histopathological assessment and lipid peroxidation or glutathione (GSH) evaluation. AP-induced barrier dysfunction was determined by an intestinal permeability assessment. Tight junction proteins and autophagy regulators were investigated by western blotting, immunohistological analysis and confocal immunofluorescence imaging. RESULTS: ANP developed as indicated by microscopic parenchymal necrosis and fat necrosis, which were associated with intestinal mucosal barrier dysfunction. HMGB1 inhibition played a protective role in intestinal mucosal barrier dysfunction, protected against microbiome changes in ANP, and relieved intestinal oxidative stress. Additionally, HMGB1 inhibition attenuated intestinal permeability; preserved the expression of TJs, such as claudin-2 and occludin; and decreased autophagy. Furthermore, the autophagy regulator LC3 and TJ protein claudin-2 were both upregulated in ANP according to dual immunofluorescence analysis. CONCLUSION: HMGB1 inhibition ameliorated the severity of experimental ANP though beneficial effects on BT, mainly involving in TJ function.

Inhibition of macrophage migration inhibitory factor attenuates inflammation and fetal kidney injury in a rat model of acute pancreatitis in pregnancy.

Acute pancreatitis in pregnancy (APIP) is a severe disease during pregnancy that mostly occurs during the third trimester. It can lead to additional complications including preterm delivery and high fetal mortality. In this study, we investigated the protective effects of (S, R)-3-(4-hydroxyphenyl)-4, 5dihydro-5-isoxazole acetic methyl ester (ISO-1), an inhibitor of macrophage migration inhibitory factor (MIF), on fetal kidney injury associated with the maternal acute necrotizing pancreatitis (ANP) and its potential mechanisms in a rat model. The APIP rat model was induced by retrograde infusion of sodium taurocholate saline solution into biliopancreatic duct. ISO-1 was given by intraperitoneally injection 30 min before the model was induced. The levels of maternal serum amylase, lipase, tumor necrosis factor-α (TNF-α) and interleukins (IL)-1ß were measured. Maternal pancreas and fetal kidney injury were evaluated, and the expressions of MIF, phospho-p38MAPK (p-p38), nuclear factor-κB (NF-κB), TNF-α, IL-1ß in fetal kidneys were detected. The results showed that fetal rats exhibited obvious acute kidney injury during APIP, and pregnant rats pretreated with ISO-1 notably attenuated the lesions. ISO-1 also significantly reduced the expression of MIF and the activations of p38MAPK, NF-κB, as well as the levels of TNF-α and IL-1ß. These results indicated that ISO-1 could attenuate fetal kidney injury in pregnant rats with ANP by inhibiting MIF mediated p38MAPK/NF-κB signal pathways to reduce inflammatory response.

Genistein protects against acute pancreatitis via activation of an apoptotic pathway mediated through endoplasmic reticulum stress in rats.

Acute pancreatitis (AP) is a severe and frequently lethal disorder, but the precise mechanisms are not well understood and there is lack of effective drugs. Therefore, our study examined the in vivo intervention effects of genistein and elucidated its mechanism in acute experimental pancreatitis models. We used cerulein or taurocholate to induce acute pancreatitis (AP) in Sprague-Dawley rats with prior genistein treatment. Histological examination of the pancreas was performed and the expression of unfolded protein response (UPR) components and apoptotic mediators like caspase 12 and c-Jun N-terminal protein kinase (JNK) were measured. The amount of apoptosis in pancreatic acinar cells was also determined. Our studies found that the severity of cerulein- or taurocholate-induced AP was rescued by prior genistein treatment. Genistein stimulated the activation of multiple endoplasmic reticulum (ER) stress-related regulators like GRP78, PERK, eIF2α, and upregulated the expression of the apoptotic genes, caspase 12 and CHOP. Moreover, TUNEL assays showed that genistein treatment promoted acinar cell apoptosis. Taken together, we speculated that ER stress-associated apoptotic pathways in AP are induced by genistein, which showed cytoprotective capacity in the exocrine pancreas. These data suggest novel therapeutic strategies that employ genistein in the prevention of AP.

Resolvin D1 Resolve Inflammation in Experimental Acute Pancreatitis by Restoring Autophagic Flux.

BACKGROUND: Acute pancreatitis (AP) is a common acute gastrointestinal disorders. Increasing evidence indicated that autophagy is involved in the development of AP. Resolvin D1 is an endogenous pro-resolving lipid mediator, which can protect mice from cerulein-induced acute pancreatitis and facilitate autophagy in macrophage, but its mechanism remians unclear. AIMS: To investigate the effect of resolvin D1 on autophagy in mouse models of cerulein-induced AP. METHODS: C57BL/6 mice were randomly divided into control group, AP group and resolvin D1 group. The models of cerulein-induced AP were constructed by intraperitoneally cerulein. Resolvin D1 group was established by intraperitoneally resolvin D1 based on AP models, simultaneously, control group received normal saline. The severity of AP, the level of inflammatory cytokines, the number of autophagic vacuoles, and the expression of autophagy-related markers were evaluated among three groups. RESULTS: The AP models were established successfully. Compared to control group, the number of autophagic vacuoles and expressions of autophagy-related markers including Beclin-1, p62 and LC3-II were increased in AP models, In contrast, the degree of inflammation and levels of inflammatory cytokines in AP models were reduced after resolvin D1 treatment. Moreover, resolvin D1 attenuated the number of autophagic vacuoles and expressions of autophagy-related markers. CONCLUSIONS: Autophagic flux is impaired in cerulein-induced AP. Resolvin D1 ameliorate the severity of mice with cerulein-induced acute pancreatitis, possible attributing to its reducing impaired autophagy and restoring autophagic flux.

Substance P-regulated leukotriene B4 production promotes acute pancreatitis-associated lung injury through neutrophil reverse migration.

Leukotriene B4 (LTB4) is a potent chemoattractant and inflammatory mediator involved in multiple inflammatory diseases. Substance P (SP) has been reported to promote production of LTB4 in itch-associated response in vivo and in some immune cells in vitro. Here, we investigated the role of LTB4 in acute pancreatitis (AP), AP-associated acute lung injury (ALI) and the related mechanisms of LTB4 production in AP. In vivo, murine AP model was induced by caerulein and lipopolysaccharide or L-arginine. The levels of LTB4 and its specific receptor BLT1 were markedly upregulated in both AP models. Blockade of BLT1 by LY293111 attenuated the severity of AP, decreased neutrophil reverse transendothelial cell migration (rTEM) into the circulation and alleviated the severity of ALI. In vitro, treatment of pancreatic acinar cells with SP increased LTB4 production. Furthermore, SP treatment increased phosphorylation of protein kinase C (PKC) α and mitogen activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK), p-38 MAPK and c-Jun NH2-terminal kinase (JNK). Finally, blockade of neurokinin-1 receptor by CP96345 significantly attenuated the severity of AP and decreased the level of LTB4 when compared to AP group. In summary, these results show that SP regulates the production of LTB4 via PKCα/MAPK pathway, which further promotes AP-associated ALI through neutrophil rTEM.

Association of Systemic Inflammatory and Anti-inflammatory Responses with Adverse Outcomes in Acute Pancreatitis: Preliminary Results of an Ongoing Study.

INTRODUCTION: This paper reports preliminary data of an ongoing study that evaluates the association of systemic inflammatory response (SIRS) with early severe acute pancreatitis (ESAP) and compensatory anti-inflammatory response syndrome (characterized by HLA-DR down-regulation) with infected pancreatic necrosis (IPN). METHODS: Consecutive patients presenting within 72 h of symptom onset with organ dysfunction and/or local complications were included. Following parameters were recorded: demographics, etiology, SIRS, APACHE II, creatinine, BUN. Circulating IL-8, IL-6, IL-10, TNF-alpha concentrations and expression of HLA-DR and IL-10 by qRT-PCR in PBMCs were measured. Strength of associations of cytokine concentration and HLA-DR/IL-10 expression with outcomes was expressed as Hedges' G and relative risk (95% CI). RESULTS: Twenty-eight patients (10 MSAP; 18 SAP) fulfilled inclusion criteria. Twelve patients had ESAP and eight presented with organ failure. Admission SIRS worsened in eight (28.6%) patients over 48 h. Sixteen (57.1%) patients developed primary IPN. Twenty-one (75%) patients had HLA-DR down-regulation during the first week, which persisted to the second week in 12 (42.9%) patients. IL-8, IL-6, and TNF-α progressively increased from healthy controls to MAP to MSAP to SAP. IL-6 and TNF-α was higher in the patients who developed ESAP (p = 0.01 and 0.05, respectively). Patients who died within the first week also had a significantly elevated concentration of IL-6 and TNF-α (p = 0.02 and 0.01, respectively). The relative risk (95% CI) of developing primary IPN with persistent HLA-DR down-regulation till the second week of illness was 11.3 (1.6-82.4; p = 0.01). CONCLUSIONS: Our study objectively demonstrates significant association of ESAP and early mortality with primary cytokine response, and development of IPN with persistent HLA-DR down-regulation.

Blockade of high-mobility group box 1 attenuates intestinal mucosal barrier dysfunction in experimental acute pancreatitis.

The release of inflammatory cytokines, that plays a dominant role in local pancreatic inflammation and systemic complications in severe acute pancreatitis (SAP). High-mobility group box 1 (HMGB1) is implicated in the mechanism of organ dysfunction and bacterial translocation in SAP. This current study aims to investigate possible role of HMGB1 in the intestinal mucosal barrier dysfunction of SAP, and the effect of anti-HMGB1 antibody treatment in intestinal mucosal injury in SAP. Our data revealed that the HMGB1 expression was significantly increased in AP mice induced by caerulein and LPS, and the inhibition of HMGB1 played a protective role in intestinal mucosal barrier dysfunction, reduced the serum level of other proinflammatory cytokines include IL-1ß, IL-6, TNF-α. Next we investigated the downstream receptors involving in HMGB1 signaling. We found that the expressions of toll-like receptor (TLR) 4 and TLR9 were elevated in ileum of AP mice, the administration of HMGB1 neutralizing antibody significantly reduced the TLR4 and TLR9 expression. It was concluded that HMGB1 contributed the mechanism to the intestinal mucosal barrier dysfunction during AP. Blockade of HMGB1 by administration of HMGB1 neutralizing antibody may be a beneficial therapeutic strategy in improving intestinal mucosal barrier dysfunction in SAP.

Resveratrol protects against L-arginine-induced acute necrotizing pancreatitis in mice by enhancing SIRT1-mediated deacetylation of p53 and heat shock factor 1.

Acute necrotizing pancreatitis (ANP) is a common severe critical illness with a high mortality rate. Resveratrol, a polyphenol compound derived from various plants such as grape skin, peanut, berry and veratrum, exhibits multiple biological activities, especially potent anti­inflammatory activity, but its effect on ANP has not yet been fully elucidated. The present study aimed to investigate the effects of resveratrol on L-arginine-induced ANP and the possible mechanisms. A mouse model of ANP was established by 2 hourly intraperitoneal injections of 8% L-arginine (4 g/kg). Then the mice were treated by intragastric administration of resveratrol (80 mg/kg) every 12 h immediately after the second injection of L-arginine. Mice with ANP showed increased apoptosis of pancreatic acinar cells, pancreatic myeloperoxidase activity, serum lactate dehydrogenase activity, amylase, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) levels as well as decreased serum IL-10 level, pancreatic expression of heat shock factor 1 (HSF1), sirtuin 1 (SIRT1) and p53, but the ratio of acetylated HSF1 and p53 was markedly increased. Resveratrol enhanced the survival rate of mice with ANP from 47.8 to 71.4% and obviously restored the changes in mice with ANP as mentioned above. Additionally, interactions between SIRT1 and p53 and between SIRT1 and HSF1 in the pancreas of the mice were confirmed by co-immunoprecipitation. These data suggest that resveratrol protects against L-arginine-induced ANP, which may be related to the enhancement of SIRT1-mediated deacetylation of p53 and HSF1.