Guotao Lu

Aspirin Protects against Acinar Cells Necrosis in Severe Acute Pancreatitis in Mice

Aspirin has a clear anti-inflammatory effect and is used as an anti-inflammatory agent for both acute and long-term inflammation. Previous study has indicated that aspirin alleviated acute pancreatitis induced by caerulein in rat. However, the role of aspirin on severe acute pancreatitis (SAP) and the necrosis of pancreatic acinar cell are not yet clear. The aim of this study was to determine the effects of aspirin treatment on a SAP model induced by caerulein combined with Lipopolysaccharide. We found that aspirin reduced serum amylase and lipase levels, decreased the MPO activity, and alleviated the histopathological manifestations of pancreas and pancreatitis-associated lung injury. Proinflammatory cytokines were decreased and the expression of NF-κB p65 in acinar cell nuclei was suppressed after aspirin treatment. Furthermore, aspirin induced the apoptosis of acinar cells by TUNEL assay, and the expression of Bax and caspase 3 was increased and the expression of Bcl-2 was decreased. Intriguingly, the downregulation of critical necrosis associated proteins RIP1, RIP3, and p-MLKL was observed; what is more, we additionally found that aspirin reduced the COX level of pancreatic tissue. In conclusion, our data showed that aspirin could protect pancreatic acinar cell against necrosis and reduce the severity of SAP. Clinically, aspirin may potentially be a therapeutic intervention for SAP.

Expression of seipin in adipose tissue rescues lipodystrophy, hepatic steatosis and insulin resistance in seipin null mice.

OBJECTIVES Gene mutations in an ER protein seipin result in congenital generalized lipodystrophy (CGL) in humans, accompanied with hepatic steatosis and insulin resistance. Seipin gene is highly expressed in the brain, testis and adipose tissue. Seipin globally deficient mice (SKO) displayed similar phenotypes as human counterparts. It has been demonstrated that adipose-specific seipin knockout mice at elder age were indistinguishable from SKO mice. Due to the large mass of adipose tissue in the body, we hypothesized that seipin in adipose tissue might be responsible for the multiple metabolism-related abnormalities in SKO mice. METHODS AND RESULTS Transgenic mice with adipose-specific expression of human seipin gene driven by aP2 promoter were generated and crossed with SKO mice to obtain adipose-specific seipin reconstitute (Seipin-RE) mice. In comparison with wild-type (WT) and SKO mice, the Seipin-RE mice exhibited normal plasma triglyceride and non-esterified fatty acids upon fasting, recovered adipose tissue mass, restored epididymal and subcutaneous fat pads morphology and partially recovered plasma leptin and adiponectin levels. Moreover, hepatic steatosis and insulin resistance was also absent in these mice. CONCLUSION Our study demonstrates that expression of seipin in adipose tissue alone could rescue dyslipidemia, lipodystrophy, hepatic steatosis and insulin resistance in SKO mice.

Development of a novel model of hypertriglyceridemic acute pancreatitis in mice

The morbidity rate of hypertriglyceridemic acute pancreatitis (HTG-AP) increased rapidly over the last decade. However an appropriate animal model was lacking to recapitulate this complicated human disease. We established a novel mice model of HTG-AP by poloxamer 407 (P-407) combined with caerulein (Cae). In our study, serum triglyceride levels of P-407 induced mice were elevated in a dose-dependent manner, and the pancreatic and pulmonary injuries were much severer in HTG mice than normal mice when injected with conventional dose Cae (50 ug/kg), what’s more, the severity of AP was positively correlative with duration and extent of HTG. In addition, we found that a low dose Cae (5 ug/kg) could induce pancreatic injury in HTG mice while there was no obvious pathological injury in normal mice. Finally, we observed that HTG leaded to the increased infiltrations of macrophages and neutrophils in mice pancreatic tissues. In conclusion, we have developed a novel animal model of HTG-AP that can mimic physiological, histological, clinical features of human HTG-AP and it could promote the development of therapeutic strategies and advance the mechanism research on HTG-AP.

Experimental Models in Syrian Golden Hamster Replicate Human Acute Pancreatitis.

The hamster has been shown to share a variety of metabolic similarities with humans. To replicate human acute pancreatitis with hamsters, we comparatively studied the efficacy of common methods, such as the peritoneal injections of caerulein, L-arginine, the retrograde infusion of sodium taurocholate, and another novel model with concomitant administration of ethanol and fatty acid. The severity of pancreatitis was evaluated by serum amylase activity, pathological scores, myeloperoxidase activity, and the expression of inflammation factors in pancreas. The results support that the severity of pathological injury is consistent with the pancreatitis induced in mice and rat using the same methods. Specifically, caerulein induced mild edematous pancreatitis accompanied by minimal lung injury, while L-arginine induced extremely severe pancreatic injury including necrosis and neutrophil infiltration. Infusion of Na-taurocholate into the pancreatic duct induced necrotizing pancreatitis in the head of pancreas and lighter inflammation in the distal region. The severity of acute pancreatitis induced by combination of ethanol and fatty acids was between the extent of caerulein and L-arginine induction, with obvious inflammatory cells infiltration. In view of the advantages in lipid metabolism features, hamster models are ideally suited for the studies of pancreatitis associated with altered metabolism in humans.

Corrigendum: Experimental Models in Syrian Golden Hamster Replicate Human Acute Pancreatitis.

Scientific Reports 6: Article number: 2801410.1038/srep28014; published online: June152016; updated: July202016 This Article contains typographical errors in the Discussion section. “Our previous study8 had proven that the local high concentration of free fatty acids in hypertriglyceridemic mice resulted in increased susceptibility to acute pancreatitis. We also had found enhanced susceptibility to acute pancreatitis in hypertriglyceridemic Syrian golden hamsters26.” should read: “Our previous study26 had proven that the local high concentration of free fatty acids in hypertriglyceridemic mice resulted in increased susceptibility to acute pancreatitis. We also had found enhanced susceptibility to acute pancreatitis in hypertriglyceridemic Syrian golden hamsters8.”

Air Medical Transportation for Severe Acute Pancreatitis Patients over an Extra Long Distance: Is It Safe Enough?

Objective Severe acute pancreatitis (SAP) patients usually develop persistent organ dysfunction which causes the majority of deaths. It is important for SAP patients to receive centralized diagnosis and treatment in an experienced tertiary center. China, as a vast country with uneven distribution of medical resources, should take advantage of air medical transportation to meet the challenge of patient transfer among different regions. The aim of this study was to evaluate the safety and effectiveness of air transport for SAP patients via extra long distance. Methods This was a retrospective analysis of all air medical transportations for SAP patients admitted to Jinling Hospital from January 2010 to December 2016. The general characteristics, transportation process, and clinical outcomes of these patients were recorded, and the safety and effectiveness of air transport were evaluated. Results All the 20 SAP patients were successfully transferred by chartered aircraft without any occurrence of severe transport-associated complications. The mean transport time was 5.86 hours and the average transport distance was 1530 kilometers. The majority of SAP patients got timely intervention and the ultimate mortality rate was 15%. Conclusions Air medical transport appears to be safe and effective for SAP patients with vital organ dysfunctions during the extra long-distance transportation.

Dynamic changes of proteasome and protective effect of bortezomib, a proteasome inhibitor, in mice with acute pancreatitis

The proteasome is involved in the activation of NF-κB and can regulate the progression of inflammatory diseases. However, the role of proteasome in acute pancreatitis (AP) has not been demonstrated. In this study, we first observed that the protein level and activity of proteasome 20S were increased significantly in pancreatic injury tissues after caerulein-induced mild acute pancreatitis (MAP) induction, which was in consistent with the expression of the NF-κB nucleoprotein and positively correlated with the severity of AP. Then, bortezomib, a classical proteasome inhibitor, was used to intervene the progression of MAP in mice. The results showed that bortezomib administration reduced the serum amylase and lipase levels and mitigated histopathological manifestation of pancreatic injury in mice. Meanwhile, bortezomib decreased the expression of NF-κB p65 nucleoprotein as well as total proteasome 20S protein, and inhibited the activity of 20S in pancreatic tissues. In addition, we found that bortezomib could protect pancreatic acinar cell against necrosis and mitigate the severity of AP in a severe acute pancreatitis model induced by sodium taurocholate hydrate. Taken together, our study for the first time confirmed that the proteasome participated in the pathogenesis of AP and its inhibitor bortezomib could protect against AP in mice.

INT-777, a bile acid receptor agonist, extenuates pancreatic acinar cells necrosis in a mouse model of acute pancreatitis

Bile acids receptor TGR5 and its agonist INT-777, which has been found to be involved in the NLRP3 inflammasome pathway, play an important role in inflammatory diseases. However, the role of INT-777 in acute pancreatitis (AP) has not been reported. In this present study, we found that TGR5 was expressed in pancreatic tissue and increased after AP onset induced by caerulein and further evaluated the impact of INT-777 on the severity of AP. The results showed that INT-777 could reduce the severity of AP in mice, which was manifested as decreased pancreatic tissue damage as well as the decrease of serum enzymes (amylase and lipase), pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and the expression of necrosis related proteins (RIP3 and p-MLKL). Furthermore, we found that INT-777 reduced the reactive oxygen species (ROS) production in pancreatic acinar cells and inhibited the activation of NLRP3 inflammasome pathway. In conclusion, our data showed that INT-777 could protect pancreatic acinar cell against necrosis and reduce the severity of AP, which may be mediated by inhibiting ROS/NLRP3 inflammasome pathway.