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Background: Data on recurrent hypertriglyceridemia-induced acute pancreatitis (HTG-AP) are scarce., Objective: To investigate the incidence and risk factors for recurrence of HTG-AP, and the effect of triglyceride (TG) lowering drugs post index attack on recurrence., Methods: This study was a prospective cohort study of adult patients with first episode of HTG-AP from December 2019 to February 2021 who were followed until recurrence or death, or February 2022. The cumulative incidence function and Fine and Gray's competing-risk model were applied to the analyses., Results: A total of 317 patients were enrolled, and the 12-month and 18-month cumulative recurrence incidences were 8% and 22%, respectively. The cumulative recurrence incidence was 2 times higher in patients whose serum TG levels post index attack were ≥5.65 mmol/L (subdistribution hazard ratio [SHR], 2.00; 95% confidence interval [CI], 1.05-3.80; P = 0.034) compared to patients with TG <5.65 mmol/L. The recurrence rate was 3.3 times higher in patients whose glucose levels post index attack were ≥7.0 mmol/L (SHR, 3.31; 95% CI, 1.56-7.03; P = 0.002) than in patients with glucose <7.0 mmol/L). Compared to TG lowering drugs for less than 1 month post index attack, treatment for longer than 12 months decreased the incidence of recurrence by 75% (SHR, 0.25; 95% CI, 0.08-0.80; P = 0.019)., Conclusions: The HTG-AP recurrence incidence is high and closely associated with high levels of TGs and glucose post index attack. Long-term TG lowering drugs treatment significantly decreases this recurrence., Competing Interests: Declaration of Competing Interest None, (Copyright © 2022. Published by Elsevier Inc.)

Background: Intestinal dysfunction is a common complication of acute pancreatitis. MiR155 may be involved in the occurrence and development of intestinal dysfunction mediated by acute pancreatitis, but the specific mechanism is not clear., Aims: To investigate the effect of miR155 on severe acute pancreatitis (SAP)-associated intestinal dysfunction and its possible mechanism in a mice model., Methods: In this study, SAP mice model was induced by intraperitoneal injection of caerulein and LPS in combination. Adeno-associated virus (AAV) was given by tail vein injection before the SAP model. The pancreatic and intestinal histopathology changes were analyzed. Cecal tissue was collected for 16S rRNA Gene Sequencing. Intestinal barrier proteins ZO-1 and E-cad were measured by Immunohistochemistry Staining and Western Blot, respectively. Intestinal tissue miR155 and inflammatory factors TNF-α, IL-1β, and IL-6 were detected by Q-PCR. The expression levels of protein associated with TNF-α and TLR4/MYD88 pathway in the intestinal were detected., Results: In miR155 overexpression SAP group, the levels of tissue inflammatory factor were significantly increased, intestinal barrier proteins were significantly decreased, and the injury of intestinal was aggravated. Bacterial 16S rRNA sequencing was performed, showing miR155 promotes gut microbiota dysbiosis. The levels of TNF-α, TLR4, and MYD88 in the intestinal were detected, suggesting that miR155 may regulate gut microbiota and activate the TLR4/MYD88 pathway, thereby affecting the release of inflammatory mediators and regulating SAP-related intestinal injury. After application of miR155-sponge, imbalance of intestinal flora and destruction of intestinal barrier-related proteins have been alleviated. The release of inflammatory mediators decreased, and the histopathology injury of intestinal was improved obviously., Conclusion: MiR155 may play an important role in SAP-associated intestinal dysfunction. MiR155 can significantly alter the intestinal microecology, aggravated intestinal inflammation through TLR4/MYD88 pathway, and disrupts the intestinal barrier in SAP mice., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Early dysbiosis of the gut microbiota is associated with the severity of acute pancreatitis (AP), although the underlying mechanism is unclear. Here, we investigated the role of crosstalk between NLRP3 and the gut microbiota in the development of AP utilizing gut microbiota deficient mice, as well as NLRP3 knockout (KO) mouse models. Pancreatic damage and systemic inflammation were improved in antibiotic-treated (Abx) and germ-free (GF) mice, accompanied by weakened activity of the intestinal NLRP3 inflammasome. Interestingly, fecal microbiota transplantation (FMT) reactivated the intestinal NLRP3 inflammasome and exacerbated the disease in Abx and GF mice. Although the gut barrier in GF and Abx mice was disrupted, gut microbiota deficiency ameliorated the severity of AP, probably due to the reduction in bacterial translocation from the gut to the pancreas. The composition of the gut microbiota was significantly different between NLRP3 KO mice and wild-type (WT) mice at baseline, and there were alterations in response to the induction of AP. While a dramatic shift in the gut microbiota with overgrowth of Escherichia-Shigella was observed in WT mice suffering from AP, there was no significant change in NLRP3 KO mice with or without AP, suggesting that NLRP3 deficiency counteracts AP-induced microbial disturbance. With a strengthened gut barrier and decreased systemic inflammation, NLRP3 KO mice showed less severe AP, as revealed by reduced pancreatic neutrophilic infiltration and necrosis. Taken together, these results identified the bidirectional modulation between the gut microbiota and NLRP3 in the progression of AP, which suggests the interplay of the host and microbiome during AP.

Hypertriglyceridemia severity is linked to acute pancreatitis prognosis, but it remains unknown why a portion of severe hypertriglyceridemia patients do not develop severe acute pancreatitis. To investigate whether hypertriglyceridemia subtypes affect acute pancreatitis progression, we analyzed two genetically modified hypertriglyceridemia mouse models-namely, glycosylphosphatidylinositol high-density lipoprotein binding protein 1 knockout (Gpihbp1-/-) and apolipoprotein C3 transgenic (ApoC3-tg) mice. Acute pancreatitis was induced by 10 intraperitoneal caerulein injections. Biochemical assays and pathological analysis were performed for the severity evaluation of acute pancreatitis. Plasma triglyceride-rich lipoproteins (TRLs), including chylomicrons and very low-density lipoprotein (VLDL), were collected via ultracentrifugation to evaluate their cytotoxic effects on primary pancreatic acinar cells (PACs). We found that the particle sizes of Gpihbp1-/- TRLs were larger than ApoC3-tg TRLs. Severe pancreatic injury with large areas of pancreatic necrosis in the entire lobule was induced in Gpihbp1-/- mice when plasma triglyceride levels were greater than 2000 mg/dL. However, ApoC3-tg mice with the same triglyceride levels did not develop large areas of pancreatic necrosis, even upon the administration of poloxamer 407 to further increase triglyceride levels. Meanwhile, in the acute pancreatitis model, free fatty acids (FFAs) in the pancreas of Gpihbp1-/- mice were greater than in ApoC3-tg mice. TRLs from Gpihbp1-/- mice released more FFAs and were more toxic to PACs than those from ApoC3-tg mice. Chylomicrons from patients showed the same effects on PACs as TRLs from Gpihbp1-/- mice. Gpihbp1-/- mice with triglyceride levels below 2000 mg/dL had milder pancreatic injury and less incidence of pancreatic necrosis than those with triglyceride levels above 2000 mg/dL, similar to Gpihbp1-/-mice with triglyceride levels above 2000 mg/dL but with fenofibrate administration. These findings demonstrated that hypertriglyceridemia subtypes with large TRL particles could affect acute pancreatitis progression and that chylomicrons showed more cytotoxicity than VLDL by releasing more FFAs.

Acute pancreatitis (AP) is a common digestive disease characterized by inflammation of the pancreas. MiR-155 plays a role in promoting inflammation and inhibiting the activation of anti-inflammatory pathways. Impaired autophagy could promote zymogen activation, abnormal acinar cell secretion, cell death, and the inflammatory response to aggravate AP. The aim of this study was to ascertain the effect of silencing miR-155 on AP through its effects on inflammation and impaired autophagy in vivo. In this study, AAV(adeno-associated virus)-mediated miR-155 and miR-155 sponge were injected through the tail vein of mice. After 3 weeks, AP was induced by intraperitoneal (IP) injections of cerulein. Pancreatic and pulmonary tissues were analyzed after 24 h. Silencing of miR-155 ameliorated pancreas and lung damage in three AP models of mice by preventing accumulation of autophagosomes that are unable to fuse with lysosomes and decreasing pancreatic inflammation by targeting TAB2. 3-MA could reduce the aberrant accumulation of autophagosomes, which alleviates the pancreas damage that was aggravated by increasing miR-155 levels. These findings demonstrate that the inhibition of miR-155 holds promise for limiting pancreatitis.

Background: The gut is implicated in the pathogenesis of acute pancreatitis (AP) and the infectious complications of AP are commonly associated with enteric bacteria, yet whether gut microbiota dysbiosis participants in AP severity remains largely unknown., Methods: We collected clinical information and fecal samples from 165 adult participants, including 41 with mild AP (MAP), 59 with moderately severe AP (MSAP), 30 with severe AP (SAP) and 35 healthy controls (HC). The serum inflammatory cytokines and gut barrier indexes were detected. Male C57BL/6 mice with AP were established and injuries of pancreas were evaluated in antibiotic-treated mice, germ-free mice as well as those transplanted with fecal microbiota. The gut microbiota was analyzed by 16S rRNA gene sequencing., Results: The structure of gut microbiota was significantly different between AP and HC, and the disturbed microbiota was closely correlated with systematic inflammation and gut barrier dysfunction. Notably, the microbial composition changed further with the worsening of AP and the abundance of beneficial bacteria such as Blautia was decreased in SAP compared with MAP and MSAP. The increased capacity for the inferred pathway, bacterial invasion of epithelial cells in AP, highly correlated with the abundance of Escherichia-Shigella. Furthermore, the antibiotic-treated mice and germ-free mice exhibited alleviated pancreatic injury after AP induction and subsequent fecal microbiota transplantation in turn exacerbated the disease., Conclusions: This study identifies the gut microbiota as an important mediator during AP and its dysbiosis is associated with AP severity, which suggests its role as potential therapeutic target.