Gut barrier dysfunction is critical in the pathogenesis of acute pancreatitis (AP), yet the underlying mechanisms remain unclear. Mucin 2 (MUC2), the primary component of the intestinal mucus layer, is essential for gut homeostasis and microbial eubiosis. This study aimed to elucidate the protective mechanism of intestinal MUC2 in AP. We reported that intestinal MUC2 expression was decreased in AP patients and correlated with disease severity. Intestinal epithelial-specific Muc2 knockout (Muc2ΔIEC) mice demonstrated exacerbated AP in a gut microbiota-dependent manner. Decreased abundance of Lactobacillus and correlated reduced levels of riboflavin were found in Muc2ΔIEC mice after AP induction. Supplementation with riboflavin effectively ameliorated AP in Muc2ΔIEC mice, whereas administration of an engineered strain deficient in riboflavin synthesis failed to provide a protective effect. MUC2 deficiency aggravated a macrophage-dominant immune imbalance in the pancreas, which was reversed by riboflavin. In vitro experiments revealed that riboflavin suppresses pro-inflammatory macrophage activation by inhibiting the CD40 signaling pathway. This inhibition preserved mitochondrial function and reversed the histone H3 acetylation at pro-inflammatory gene promoters. Our study demonstrates that intestinal MUC2 deficiency is associated with reduced levels of microbiota-derived riboflavin, which could partially suppress pro-inflammatory macrophage activation via the CD40 pathway. Targeting the microbiota-derived riboflavin in AP may help to ameliorate the disease course.

Mucin-2 (MUC2) plays a crucial role in maintaining intestinal homeostasis during acute pancreatitis (AP). We aimed to investigate the role of B3GNT7 (β-1,3-N-acetylglucosamine transferase) in the O-glycosylation of MUC2 in AP. We used two mouse models of AP induced by caerulein/lipopolysaccharide or L-arginine, and observed colonic goblet cells using electron microscopy, noting that Golgi damage was linked to decreased levels of mature MUC2. Golgi stress–associated proteins (reduced GM130 and elevated GOLPH3) were identified using immunofluorescence. Transcriptome analysis revealed the downregulation of B3gnt7, a glycosyltransferase that is highly enriched in the Golgi apparatus of goblet cells in AP mice. B3GNT7 expression was negatively correlated with pancreatic and colonic pathological scores. In patients with AP, intestinal B3GNT7 levels are markedly reduced and correlated with Ranson scores, C-reactive protein levels, and intestinal permeability markers (serum diamine oxidase and D-lactate). Adeno-associated virus (AAV)-mediated knockdown of B3GNT7 reduced O-glycosylated MUC2 levels, exacerbated pancreatic and systemic inflammation, and worsened intestinal permeability and dysbiosis. In vitro, LPS-treated HT-29 cells exhibited Golgi stress (decreased levels of B3GNT7 and O-glycosylated MUC2) that was reversed by L-glutathione (GSH). These findings demonstrate that B3GNT7 downregulation, mediated by Golgi stress, disrupts MUC2 O-glycosylation, exacerbating AP by impairing intestinal homeostasis.

Acute pancreatitis (AP) is a complex gastrointestinal disorder associated with disruptions in the gut microbiome. However, the gut microbial and metabolomic profiles in recurrent acute pancreatitis (RAP), which is a clinically distinct subtype of AP, remain unclear. This study integrated microbiome-metabolome analysis to identify the key gut microbial species and metabolic pathways associated with RAP. The findings reveal that the abundance of Faecalibacterium prausnitzii (Fp) is significantly diminished in RAP patients, exhibiting a strong negative correlation with disease severity. Consistent with this observation, fecal microbiota transplantation enriched with Fp significantly ameliorated pancreatic injury in RAP mice. We further isolated Fp Ai 3−16 strain from the stool of healthy volunteers. Functional validation using experimental AP models demonstrates that Fp Ai 3-16 and its metabolite oleic acid (OA) can effectively attenuate pancreatitis by modulating MAPK/NF-κB signaling pathways and restoring the intestinal Th17/Treg balance. Importantly, these results extend beyond the context of RAP, as they highlight the broader significance of the gut-pancreas axis in the pathogenesis of AP. Thus, the elucidation of the underlying molecular mechanisms offers novel therapeutic avenues for RAP management and provides a foundation for further investigations into the intricate interplay between the gut microbiome and the pancreas.

Fecal microbiota transplantation (FMT) is a promising therapy for inflammatory bowel disease (IBD) via rectifying gut microbiota. The aim of this study was to identify a mechanism of how specific bacteria-associated immune response contributes to alleviated colitis. Forty donors were divided into high (donor H) and low (donor L) groups according to the diversity and the abundance of Bacteroides and Faecalibacterium by 16S rRNA sequencing. FMT was performed on dextran sulfate sodium (DSS)-induced colitis in mice. Mice with colitis showed significant improvement in intestinal injury and immune imbalance after FMT with group donor H (P < 0.05). Bacteroides thetaiotaomicron and Faecalibacterium prausnitzii were identified as targeted strains in donor feces by real-time PCR and droplet digital PCR. Mice with colitis were treated with mono- or dual-bacterial gavage therapy. Dual-bacterial therapy significantly ameliorated intestinal injury compared with mono-bacterial therapy (P < 0.05). Dual-bacterial therapy increased the M2/M1 macrophage polarization and improved the Th17/Treg imbalance and elevated IL-10 production by Tregs compared with the DSS group (P < 0.05). Metabolomics showed increased abundance of lecithin in the glycerophospholipid metabolism pathway. In conclusion, B. thetaiotaomicron and F. prausnitzii, as the key bacteria in donor feces, alleviate colitis in mice. The mechanism may involve increasing lecithin and regulating IL-10 production of intestinal Tregs. NEW & NOTEWORTHY We demonstrate that donors with high abundance of Bacteroides and Faecalibacterium ameliorate dextran sulfate sodium (DSS)-induced colitis in mice by fecal microbiota transplantation (FMT). The combination therapy of Bacteroides thetaiotaomicron and Faecalibacterium prausnitzii is superior to mono-bacterial therapy in ameliorating colitis in mice, of which mechanism may involve promoting lecithin and inducing IL-10 production of intestinal Tregs.

Intestinal barrier dysfunction usually occurred in acute pancreatitis (AP) but the mechanism remains unclear. In this study, RNA sequencing of ileum in L-arginine-induced AP mice demonstrated that phosphoenolpyruvate kinase 1 (Pck1) was significantly up-regulated. Increased Pck1 expression in intestinal epithelial cells (IECs) was further validated in ileum of AP mice and duodenum of AP patients. In AP mice, level of Pck1 was positively correlated with pancreatic and ileal histopathological scores, serum amylase activity, and intestinal permeability (serum diamine oxidase (DAO), D-lactate, and endotoxin). In AP patients, level of Pck1 had a positive correlation with Ranson scores, white blood cell count and C-reactive protein. Inhibition of Pck1 by 3-Mercaptopicolinic acid hydrochloride (3-MPA) alleviated pancreatic and ileal injuries in AP mice. AP + 3-MPA mice showed improved intestinal permeability, including less epithelial apoptosis, increased tight junction proteins (TJPs) expression, decreased serum DAO, D-lactate, endotoxin, and FITC-Dextran levels, and reduced bacteria translocation. Lysozyme secreted by Paneth cells and mucin2 (MUC2) secretion in goblet cells were also partly restored in AP + 3-MPA mice. Meanwhile, inhibition of Pck1 improved intestinal immune response during AP, including elevation of M2/M1 macrophages ratio and secretory immunoglobulin A (sIgA) and reduction in neutrophils infiltration. In vitro, administration of 3-MPA dramatically ameliorated inflammation and injuries of epithelial cells in enteroids treated by LPS. In conclusion, inhibition of Pck1 in IECs might alleviate AP via 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-alpha-treated colonoids had exacerbated goblet cell dysfunction. MUC2 expression was negatively correlated with the levels of pro-inflammatory cytokines (IL-1 beta 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.

Objective:To explore the effect of probiotics Lactiplantibacillus plantarum(LP) WCFS1 by gavage on acute necrotizing pancreatitis (ANP) and associated ileum injury in mice. Methods:Twenty-four healthy male mice were gavaged with broad-spectrum antibiotics for 3 weeks to establish microbiota-depleted mice, and then randomly divided into control group (CON), ANP model group (ANP), LP gavage group (LP) and LP gavage and ANP induced group (LP+ ANP) , with 6 mice in each group. Mice in LP and LP+ ANP group were treated by gavage of LP (1×10 9 CFU/ml, 0.2 ml/day per mouse) for 1 week, while CON and ANP were gavaged with sterile phosphate buffered saline for 1 week instead. The ANP model was induced by intraperitoneal injection with caerulein (100 μg/kg) for 10 times with 1-hour interval between two injections and the 10th injection with lipopolysaccharide(LPS) 5 mg/kg intraperitoneally, and the mice were sacrificed 2 h later. Levels of LP in stool and ileal mucosa were detected by real-time PCR; the pancreas and ileum were collected for pathological examination to observe the extent of tissue inflammation and to score the pathology. Serum amylase activities were determined by enzymatic kinetic chemistry; serum inflammators levels and intestinal permeability were detected by ELISA; levels of inflammators in pancreatic and ileal tissues were detected by real-time PCR; ileal tight-junction proteins (occludin, claudin-1 and ZO-1) were measured by immunofluorescence staining. Results:LP levels in the stool and ileal mucosa of mice were significantly increased after LP gavage, and the differences were statistically significant (913.30±39.12 vs 2.39±1.39, 23.11±0.50 vs 1.38±0.28, all P value <0.05). The pathological scores of pancreatic tissue of CON, LP, ANP and LP+ ANP group were (0.26±0.41), (0.17±0.26), (8.55±0.46) and (6.30±0.45); the serum amylase activities were (219.70±19.73), (217.60±11.30), (2896.24±98.32) and (1837.13±131.60)U/L, IL-1β were (0.87±0.28), (1.4±0.85), (67.41±6.45) and (36.33±5.65)pg/ml, IL-6 were (0.74±0.27), (0.16±0.16), (280586.12±39163.92) and (107912.75±31283.47)pg/ml, IL-10 were (35.52±5.27), (50.99±15.34), (2008.45±184.83) and (3070.35±403.71)pg/ml; the expression level of pancreatic IL-1β mRNA was 1.42±0.39, 0.95±25, 20.53±0.50 and 10.69±1.01, IL-6 mRNA was 1.31±0.44, 0.93±0.023, 21.97±1.71 and 11.54±1.75, IL-10 mRNA was 0.93±0.14, 0.75±0.15, 0.99±0.21 and 1.76±0.19; there was no significant difference between LP and CON group, and pancreatic pathological scores, serum amylase、IL-1β and IL-6 levels, and the expression level of pancreatic IL-1β and IL-6 mRNA were significantly decreased in LP+ ANP group compared with those in ANP group, while serum IL-10 levels and the expression level of pancreatic IL-10 mRNA were significantly increased compared with ANP group, and all the differences were statistically significant (all P values <0.05). The pathological scores of ileal tissue of CON, LP, ANP and LP+ ANP group were 0, 0, (3.17±0.41) and (1.67±0.52); the levels of serum DAO of CON, LP, ANP and LP+ ANP group were (0.03±0.03), (0.02±0.02), (0.50±0.05) and (0.49±0.06)ng/ml; LPS levels were (2.75±0.35), (3.74±0.28), (7.19±0.92) and (5.88±0.38)ng/ml; the expression level of ileal IL-1β mRNA was 1.21±0.20, 1.17±0.09, 1.81±0.25 and 1.63±0.21; IL-6 mRNA was 1.01±0.29, 2.83±0.42, 54.45±8.50 and 16.87±4.42; IL-10 mRNA was 1.12±0.41, 6.09±2.51, 11.65±1.47 and 29.86±2.93. There was no significant difference between LP and CON group, except that the ileal IL-10 mRNA expression was significantly higher than that of CON group. Ileal pathological scores, serum LPS levels and the expression level of ileal IL-6 mRNA were significantly lower in LP+ ANP group than those in ANP group, while the expression level of ileal IL-10 mRNA was significantly higher than that of ANP group; the expression of ileal tight junction proteins (ocludin, claudin-1, ZO-1) was significantly higher than those in ANP group, and all the differences were statistically significant (all P values <0.05). Conclusions:LP WCFS1 gavage could ameliorate the injury of pancreatic and ileal barrier in caerulein-induced ANP mice.

Objective To compare efficacy and safety of fecal microbiota transplantation (FMT) with glucocorticoid as induction therapy in ulcerative colitis (UC). Methods The patients with active mild to moderate UC were recruited into the single-center, prospective cohort study. The patients were treated with either FMT (FMT group) or glucocorticoids (GCs group). Patients received FMT administration for 3 days. The primary outcome was clinical and endoscopic remission at week 12. Inflammatory parameters were assessed by routine blood tests. Safety was assessed by adverse events recorded. The serum levels of TNF-α, IFN-γ, IL-1β, IL-4, IL-5, IL-6, IL-10 IL-8, IL-12p70, IL-13, IL-17A and IL-23 following FMT were measured by Luminex multiplex assay. Results Of the 122 patients, 62 patients were treated with FMT and 60 with glucocorticoids. 34 patients in FMT group (54.8%) and 29 in GCs group (48.3%) reached the primary outcome ( p = 0.30). The incidence of adverse events in GCs group (35/60, 58.3%) was significantly higher than that in FMT group (14/62, 22.6%) and two serious adverse events were observed following GCs. Patients in FMT group were stratified into responders (RE) and non-responders (NR) groups. The level of TNF-α and IL-6 decreased significantly in RE group, while IL-10 decreased significantly in NR group. Conclusion FMT therapy was as effective as glucocorticoids to induce remission in active mild to moderate UC, accompanied by fewer adverse events. The modification of serum TNF-α, IL-6 and IL-10 might be related to the efficacy of FMT in UC. Trial registration This study was registered with ClinicalTrials.gov (NCT02435160). Registered on 6 April, 2015. https://clinicaltrials.gov/ct2/results?cond=&term=NCT02435160&cntry=&state=&city=&dist=

Background: Fecal microbiota transplantation (FMT) may contribute to disease remission in ulcerative colitis (UC). We studied the microbiota change and its regulation on T cells after FMT. Methods: Patients with mild to moderately active UC were included to receive FMT. The intestinal histopathological changes and barrier function were evaluated. The fecal samples of donors and patients were analyzed by 16S rRNA gene-based microbiota analysis, and the colon Th17 and Treg cells were assessed. Results: Fifteen patients completed the 8-week-follow-up. A total of 10 patients (66.7%) were in the responders (RE) group and five in the non-responders (NR) group. The Nancy histological index and fecal calprotectin decreased (p < 0.001, p = 0.06, respectively) and Occludin and Claudin1 increased in the RE group. The abundance of Faecalibaterium increased significantly by 2.3-fold in the RE group at week 8 (p = 0.043), but it was suppressed in the NR group. Fecal calprotectin (r = −0.382, p = 0.003) and Nancy index (r = −0.497, p = 0.006) were correlated inversely with the abundance of Faecalibacterium, respectively. In the RE group the relative mRNA expression of RORγt decreased and Foxp3 increased. Significantly decreased CD4+ RORγt+ Th17 and increased CD4+ Foxp3+ Treg were also observed in the RE group. The relative abundance of Faecalibacterium correlated with CD4+ RORγt+ Th17 (r = −0.430, p = 0.018) and CD4+ Foxp3+ Treg (r = 0.571, p = 0.001). Conclusions: The long-term Faecalibaterium colonization following FMT plays a crucial role in UC remission by alleviating intestinal inflammation. This anti-inflammatory effect of Faecalibacterium may be achieved by regulating the imbalance of Th17/Treg levels in UC.

Toll-like receptor 4 (TLR4) has been identified as a potentially promising therapeutic target in acute pancreatitis (AP). However, the role of intestinal TLR4 in AP and AP-associated gut injury remains unclear. This study aimed to explore the relationship between intestinal TLR4 and gut microbiota during AP. A mouse AP model was establish by intraperitoneal injection of L-arginine. Pancreatic injury and intestinal barrier function were evaluated in wild-type and intestinal epithelial TLR4 knockout (TLR4ΔIEC) mice. Gut microbiota was analyzed by 16S rRNA sequencing. Quadruple antibiotics were applied to induce microbiota-depleted mice. Differentially expressed genes in gut were detected by RNA sequencing. L. reuteri treatment was carried out in vivo and vitro study. Compared with wild-type mice, AP and AP-associated gut injury were exacerbated in TLR4ΔIEC mice in a gut microbiota-dependent manner. The relative abundance of Lactobacillus and number of Paneth cells remarkably decreased in TLR4ΔIEC mice. The KEGG pathway analysis derived from RNA sequencing suggested that genes affected by intestinal TLR4 deletion were related to the activation of nod-like receptor pathway. Furthermore, L. reuteri treatment could significantly improve the pancreatic and intestinal injury in TLR4ΔIEC mice through promoting Paneth cells in a NOD2-dependent manner. Loss of intestinal epithelial TLR4 exacerbated pancreatic and intestinal damage during AP, which might be attributed to the gut microbiota dysbiosis especially the exhausted Lactobacillus. L. reuteri might maintain intestinal homeostasis and alleviate AP via Paneth cells modulation.Abbreviations: AP Acute pancreatitis, TLR4 Toll-like receptor 4, IL-1β Interleukin-1β, IL-6 Interleukin-6, TNF-α Tumor necrosis factor-α, SIRS Systematic inflammatory response syndrome, LPS Lipopolysaccharides, SPF Specific pathogen-free, ZO-1 Zonula occludens-1, CON Control, H&E Hematoxylin and eosin, FISH Fluorescence in situ hybridization, DAPI 4',6-diamidino-2-phenylindole, PCoA Principal co-ordinates analysis, SCFA Short chain fatty acid, LEfSe Linear discriminant analysis Effect Size, ANOVA Analysis of variance, F/B Firmicutes/Bacteroidetes, PCA Principal component analysis, NOD2 Nod-like receptor 2, ABX antibiotics, PCNA proliferating cell nuclear antigen.

We demonstrate that AP patients and experimental AP mice exhibited a dysfunction of Paneth cells. Our in vivo research showed that the severity of AP was exacerbated by the long-term dysfunction of Paneth cells, which was associated with gut microbiota disorder.

Severe acute pancreatitis (SAP) is a severe acute abdominal disease. Recent evidence shows that intestinal homeostasis is essential for the management of acute pancreatitis. Chitosan oligosaccharides (COS) possess antioxidant activity that are effective in treating various inflammatory diseases. In this study we explored the potential therapeutic effects of COS on SAP and underlying mechanisms. Mice were treated with COS (200 mg·kg−1·d−1, po) for 4 weeks, then SAP was induced in the mice by intraperitoneal injection of caerulein. We found that COS administration significantly alleviated the severity of SAP: the serum amylase and lipase levels as well as pancreatic myeloperoxidase activity were significantly reduced. COS administration suppressed the production of proinflammatory cytokines (TNF-α, IL-1β, CXCL2 and MCP1) in the pancreas and ileums. Moreover, COS administration decreased pancreatic inflammatory infiltration and oxidative stress in SAP mice, accompanied by activated Nrf2/HO-1 and inhibited TLR4/NF-κB and MAPK pathways. We further demonstrated that COS administration restored SAP-associated ileal damage and barrier dysfunction. In addition, gut microbiome analyses revealed that the beneficial effect of COS administration was associated with its ability to improve the pancreatitis-associated gut microbiota dysbiosis; in particular, probiotics Akkermansia were markedly increased, while pathogenic bacteria Escherichia–Shigella and Enterococcus were almost eliminated. The study demonstrates that COS administration remarkably attenuates SAP by reducing oxidative stress and restoring intestinal homeostasis, suggesting that COS might be a promising prebiotic agent for the treatment of SAP. Supplementation of chitosan oligosaccharides(COS) could ameliorate severity of pancreatic injury, prevent intestinal barrier disruption and reduce inflammatory and oxidative injury in severe acute pancreatitis (SAP). The protective mechanism partly attributed to the reshaping of gut microbiota and TLR4 and Nrf2/HO-1 pathway.

ObjectiveTo investigate the potential therapeutic role of porous SiO2‐coated ultrasmall selenium particles nanospheres (Se@SiO2 nanospheres) pretreatment in acute pancreatitis (AP) and to investigate the related mechanism.MethodsC57BL/6 mice were randomized to the normal control (CON) group, the AP (induced by cerulein injection) (CAE) group, and AP pretreated with Se@SiO2 nanocomposites at 1 and 2 mg/kg (CAE + 1 or 2 mg/kg Se@SiO2) groups, respectively. Serum levels of amylase and lipase, inflammatory cytokines (interleukin [IL]‐6, IL‐1β and tumor necrosis factor [TNF]‐α), alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and creatinine (Cr) were measured, and histopathology was performed to examine the tissue samples of the pancreas, lungs, kidneys and liver. Immunofluorescence assay of reactive oxygen species (ROS), myeloperoxidase (MPO) and terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labeling were conducted, and levels of MPO, malondialdehyde, superoxide dismutase and glutathione were evaluated. Finally, Western blot analysis was used to evaluate protein expressions of Nrf2, HO‐1, NQO1, TLR4, MyD88 and p‐p65 in pancreatic tissue.ResultsSe@SiO2 nanospheres alleviated pathological damage to the pancreas, and reduced pancreatic enzymes and inflammatory cytokines. Injury to other organs such as the liver, lungs and kidneys was also alleviated, as indicated by decreased ALT, AST, BUN, and Cr levels as well as improved histopathology. Moreover, Se@SiO2 nanospheres reduced oxidative stress, and ultimately inhibited TLR4/ MyD88/p‐p65 pathway and increased the protein expressions of NQO1, Nrf2, and HO‐1.ConclusionSe@SiO2 nanospheres may alleviate AP by relieving oxidative stress and targeting the TLR4/Myd88/p‐p65 and NQO1/Nrf2/HO‐1 pathways.

背景:急性胰腺炎(AP)是临床常见急腹症,重症AP(SAP)病情进展迅速,可导致全身炎症反应综合征、多器官功能衰竭甚至死亡.早期识别重症患者并及时采取有效治疗措施可改善预后,降低病死率.目的:探讨C反应蛋白(CRP)、白细胞介素-6(IL-6)和降钙素原(PCT)单项或联合检测在病程早期对AP严重程度的预测价值.方法:回顾性纳入上海交通大学医学院附属第一人民医院2018年1月—2020年12月收治的472例AP患者,采集入院48 h内实验室指标,并根据2012年修订版亚特兰大分类标准分为轻症AP(MAP)组和SAP组[包括中度SAP(MSAP)和SAP].比较两组间CRP、IL-6、PCT水平的差异,以ROC曲线分析三项指标单项或联合检测对SAP的预测价值.结果:SAP组CRP、IL-6、PCT水平均明显高于MAP组,差异有统计学意义(P均<0.05).ROC曲线分析显示,三项指标单项、两两联合和三项联合检测预测SAP的曲线下面积(AUC)均>0.7,具有一定的诊断准确性;三项联合检测诊断准确性最高(AUC=0.826),敏感性和特异性分别为71.4％和79.3％.结论:CRP、IL-6和PCT检测可用于AP病情严重程度的早期评估,三项联合检测预测SAP的总体诊断价值最优.

To investigate the potential therapeutic role of porous SiO 2 -coated ultrasmall selenium particles nanospheres (Se@SiO 2 nanospheres) pretreatment in acute pancreatitis (AP) and to investigate the related mechanism. C57BL/6 mice were randomized to the normal control (CON) group, the AP (induced by cerulein injection) (CAE) group, and AP pretreated with Se@SiO 2 nanocomposites at 1 and 2 mg/kg (CAE + 1 or 2 mg/kg Se@SiO 2 ) groups, respectively. Serum levels of amylase and lipase, inflammatory cytokines (interleukin [IL]-6, IL-1β and tumor necrosis factor [TNF]-α), alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and creatinine (Cr) were measured, and histopathology was performed to examine the tissue samples of the pancreas, lungs, kidneys and liver. Immunofluorescence assay of reactive oxygen species (ROS), myeloperoxidase (MPO) and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling were conducted, and levels of MPO, malondialdehyde, superoxide dismutase and glutathione were evaluated. Finally, Western blot analysis was used to evaluate protein expressions of Nrf2, HO-1, NQO1, TLR4, MyD88 and p-p65 in pancreatic tissue. Se@SiO 2 nanospheres alleviated pathological damage to the pancreas, and reduced pancreatic enzymes and inflammatory cytokines. Injury to other organs such as the liver, lungs and kidneys was also alleviated, as indicated by decreased ALT, AST, BUN, and Cr levels as well as improved histopathology. Moreover, Se@SiO 2 nanospheres reduced oxidative stress, and ultimately inhibited TLR4/ MyD88/p-p65 pathway and increased the protein expressions of NQO1, Nrf2, and HO-1. Se@SiO 2 nanospheres may alleviate AP by relieving oxidative stress and targeting the TLR4/Myd88/p-p65 and NQO1/Nrf2/HO-1 pathways.

Severe acute pancreatitis (SAP) is associated with high rates of mortality and morbidity. Chitosan oligosaccharides (COSs) are agents with antioxidant properties. We developed porous COS@SiO2 nanocomposites to study the protective effects and mechanisms of COS nanomedicine for the treatment of acute pancreatitis. Porous COS@SiO2 nanocomposites released COSs slowly under pH control, enabling sustained release and maintaining the drug at a higher concentration. This study aimed to determine whether porous COS@SiO2 nanocomposites ameliorate SAP and associated lung injury. The SAP model was established in male C57BL/6 mice by intraperitoneal injection of caerulein. The expression levels of myeloperoxidase, malondialdehyde, superoxide dismutase, nuclear factor-kappa B (NF-κB), the NOD-like receptor protein 3 (NLRP3) inflammasome, nuclear factor E2-related factor 2 (Nrf2), and inflammatory cytokines were detected, and a histological analysis of mouse pancreatic and lung tissues was performed. In the SAP groups, systemic inflammation and oxidative stress occurred, and pathological damage to the pancreas and lung was obvious. Combined with porous COS@SiO2 nanocomposites before treatment, the systemic inflammatory response was obviously reduced, as were oxidative stress indicators in targeted tissues. It was found that Nrf2 was significantly activated in the COS@SiO2 treatment group, and the expressions of NF-κB and the NLRP3 inflammasome were notably decreased. In addition, this protective effect was significantly weakened when Nrf2 signaling was inhibited by ML385. This demonstrated that porous COS@SiO2 nanocomposites activate the Nrf2 signaling pathway to inhibit oxidative stress and reduce the expression of NF-κB and the NLRP3 inflammasome and the release of inflammatory factors, thus blocking the systemic inflammatory response and ultimately ameliorating SAP and associated lung injury.

背景:研究表明,肠屏障功能障碍与急性坏死性胰腺炎(ANP)的发生、发展密切相关.目的:探讨L-精氨酸诱导的ANP小鼠肠屏障损伤及其加重ANP的机制.方法:将30只C57BL/6小鼠随机分为假手术组(SO组)和ANP组.ANP组小鼠给予腹腔注射8％L-精氨酸(4.5 g/kg)共两次,间隔为1 h;SO组则腹腔注射等体积0.9％NaCl溶液.造模24 h、48 h和72 h后处死小鼠,行HE染色评估胰腺和肠道病理学评分,检测血清淀粉酶、脂肪酶水平,以ELISA法评估炎症因子(IL-1β、IL-6、TNF-α)和肠道通透性(DAO、D-乳酸、LPS)水平,蛋白质印迹法检测胰腺组织和肠道组织TLR4、MyD88蛋白表达.结果:与SO组相比,ANP组相应时间点胰腺组织和回肠组织病理学评分显著增高(P<0.05),血清淀粉酶、脂肪酶、炎症因子(IL-1β、IL-6、TNF-α)、肠道通透性指标(DAO、D-乳酸、LPS)水平均显著增高(P<0.05),胰腺组织和回肠组织TLR4、MyD88蛋白表达显著增高(P<0.05).结论:L-精氨酸诱导的ANP小鼠肠道通透性增加,LPS释放增多,可能通过激活TLR4-MyD88信号通路促进肠道、全身炎症反应,进而加重ANP.

Aim. Monocytes play an important role in acute pancreatitis (AP). Hypertriglyceridemic pancreatitis (HTGP) is always more severe than normal lipid-AP, whether the mechanism of aggravation involves monocyte subsets remains unknown though. The present study was aimed to analyze changes of peripheral blood M1 and M2 monocytes in HTGP patients. Methods. A total of 90 subjects were enrolled, among which 16 diagnosed with HTGP, 34 with acute biliary pancreatitis (ABP), 20 with hypertriglyceridemia (HTG), and 20 healthy controls (HC). Peripheral blood CD14+CD86+ M1 and CD14+CD206+ M2 monocytes were examined by flow cytometry on days 1, 3, and 7 after admission. Results. We found a marked increase in total and M1 monocyte count in AP patients (P<0.05). In HTGP, the percentage of M1 monocytes in white blood cells was significantly higher on days 1, 3, and 7, while M2 monocyte percentage was decreased on day 3, compared with ABP (P<0.05). In mild HTGP, M1 monocyte count and percentage gradually decreased, while M2 monocyte percentage gradually increased from day 1 to 7. In severe HTGP, M1 monocyte count and percentage rose to the highest point while M2 were the lowest on day 3. Additionally, the level of M1 monocytes showed a positive correlation with plasma triglyceride and Ranson score of HTGP patients. Conclusions. Peripheral blood M1 and M2 monocytes showed different dynamic changes in mild and severe HTGP. A more dominant role of CD14+CD86+ M1 monocytes may be involved in the pathogenesis of HTGP.

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-1β, 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.