Role of the gut in the course of severe acute pancreatitis

Very early and early nutrition in children with pancreatitis-A randomised trial

OBJECTIVES

The aim of our study was to assess the impact of the very early introduction of refeeding on the course of acute pancreatitis (AP) in children. Additionally, we evaluated the effect of nutrition on inflammatory markers, including cytokines.

METHODS

This prospective randomised study was conducted in three university hospitals in Poland. Patients, aged 1-18 years with AP, were randomised into two groups: A-refeeding within 24 h of hospital admission (very early), and B-refeeding at least 24 h after admission (early nutrition). The severity of AP was assessed after 48 h. The serum concentrations of four cytokines (tumour necrosis factor α [TNFα], interleukin-1β [IL-1β], interleukin-6 [IL-6] and interleukin-8 [IL-8]) and C-reactive protein, as well as the activity of amylase, lipase and aminotransferases, were measured during the first 3 days of hospitalisation.

RESULTS

A total of 94 children were recruited to participate in the study. The statistical analysis included 75 patients with mild pancreatitis: 42-group A and 33-group B. The two groups did not differ in the length of hospitalisation (p = 0.22), AP symptoms or results of laboratory tests. Analysis of cytokine levels was conducted for 64 children: 38-group A and 26-group B. We did not find a difference in concentrations of the measured cytokines, except for IL-1β on the third day of hospitalisation (p = 0.01).

CONCLUSIONS

The time of initiation of oral nutrition within 24 h (very early) or after 24 h (early) from the beginning of hospitalisation had no impact on the length of hospitalisation, concentrations of TNF-α, IL-1β, IL-6 and IL-8, activity of amylase and lipase or occurrence of symptoms in children with mild AP.

Exploring the gut microbiota's crucial role in acute pancreatitis and the novel therapeutic potential of derived extracellular vesicles

During acute pancreatitis, intestinal permeability increases due to intestinal motility dysfunction, microcirculatory disorders, and ischemia-reperfusion injury, and disturbances in the intestinal flora make bacterial translocation easier, which consequently leads to local or systemic complications such as pancreatic and peripancreatic necrotic infections, acute lung injury, systemic inflammatory response syndrome, and multiple organ dysfunction syndrome. Therefore, adjusting intestinal ecosystem balance may be a promising approach to control local and systemic complications of acute pancreatitis. In this paper, we reviewed the causes and manifestations of intestinal flora disorders during acute pancreatitis and their complications, focused on the reduction of acute pancreatitis and its complications by adjusting the intestinal microbial balance, and innovatively proposed the treatment of acute pancreatitis and its complications by gut microbiota-derived extracellular vesicles.

No Effect of Methylnaltrexone on Acute Pancreatitis Severity: A Multicenter Randomized Controlled Trial

INTRODUCTION

Opioids used to manage severe pain in acute pancreatitis (AP) might exacerbate the disease through effects on gastrointestinal and immune functions. Methylnaltrexone, a peripherally acting µ-opioid receptor antagonist, may counteract these effects without changing analgesia.

METHODS

This double-blind, randomized, placebo-controlled trial included adult patients with AP and systemic inflammatory response syndrome at 4 Danish centers. Patients were randomized to receive 5 days of continuous intravenous methylnaltrexone (0.15 mg/kg/d) or placebo added to the standard of care. The primary end point was the Pancreatitis Activity Scoring System score after 48 hours of treatment. Main secondary outcomes included pain scores, opioid use, disease severity, and mortality.

RESULTS

In total, 105 patients (54% men) were randomized to methylnaltrexone (n = 51) or placebo (n = 54). After 48 hours, the Pancreatitis Activity Scoring System score was 134.3 points in the methylnaltrexone group and 130.5 points in the placebo group (difference 3.8, 95% confidence interval [CI] -40.1 to 47.6; P = 0.87). At 48 hours, we found no differences between the groups in pain severity (0.0, 95% CI -0.8 to 0.9; P = 0.94), pain interference (-0.3, 95% CI -1.4 to 0.8; P = 0.55), and morphine equivalent doses (6.5 mg, 95% CI -2.1 to 15.2; P = 0.14). Methylnaltrexone also did not affect the risk of severe disease (8%, 95% CI -11 to 28; P = 0.38) and mortality (6%, 95% CI -1 to 12; P = 0.11). The medication was well tolerated.

DISCUSSION

Methylnaltrexone treatment did not achieve superiority over placebo for reducing the severity of AP.

Nomogram for the prediction of infected pancreatic necrosis in moderately severe and severe acute pancreatitis

OBJECTIVES

As a serious complication of moderately severe acute pancreatitis (MSAP) and severe acute pancreatitis (SAP), infected pancreatic necrosis (IPN) can lead to a prolonged course of interventional therapy. Most predictive models designed to identify such patients are complex or lack validation. The aim of this study was to develop a predictive model for the early detection of IPN in MSAP and SAP.

METHODS

A total of 594 patients with MSAP or SAP were included in the study. To reduce dimensionality, least absolute shrinkage and selection operator regression analysis was used to screen potential predictive variables, a nomogram was then constructed using logistic regression analysis. The receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the discrimination, accuracy, and clinical efficacy of the model. External data were also obtained to further validate the constructed model.

RESULTS

There were 476, 118, and 82 patients in the training, internal validation, and external validation cohorts, respectively. Platelet count, hematocrit, albumin/globulin, severity of acute pancreatitis, and modified computed tomography severity index score were independent factors for predicting IPN in MSAP and SAP. The area under the ROC curves were 0.923, 0.940, and 0.817, respectively, in the three groups. There was a good consistency between the actual probabilities and the predicted probabilities. DCA revealed excellent clinical utility.

CONCLUSION

The constructed nomogram is a simple and feasible model that has good clinical predictive value and efficacy in clinical decision-making for IPN in MSAP and SAP.

Integrative metagenomic and metabolomic analyses reveal the potential of gut microbiota to exacerbate acute pancreatitis

Early dysbiosis in the gut microbiota may contribute to the severity of acute pancreatitis (AP), however, a comprehensive understanding of the gut microbiome, potential pathobionts, and host metabolome in individuals with AP remains elusive. Hence, we employed fecal whole-metagenome shotgun sequencing in 82 AP patients and 115 matched healthy controls, complemented by untargeted serum metabolome and lipidome profiling in a subset of participants. Analyses of the gut microbiome in AP patients revealed reduced diversity, disrupted microbial functions, and altered abundance of 77 species, influenced by both etiology and severity. AP-enriched species, mostly potential pathobionts, correlated positively with host liver function and serum lipid indicators. Conversely, many AP-depleted species were short-chain fatty acid producers. Gut microflora changes were accompanied by shifts in the serum metabolome and lipidome. Specifically, certain gut species, like enriched Bilophila wadsworthia and depleted Bifidobacterium spp., appeared to contribute to elevated triglyceride levels in biliary or hyperlipidemic AP patients. Through culturing and whole-genome sequencing of bacterial isolates, we identified virulence factors and clinically relevant antibiotic resistance in patient-derived strains, suggesting a predisposition to opportunistic infections. Finally, our study demonstrated that gavage of specific pathobionts could exacerbate pancreatitis in a caerulein-treated mouse model. In conclusion, our comprehensive analysis sheds light on the gut microbiome and serum metabolome in AP, elucidating the role of pathobionts in disease progression. These insights offer valuable perspectives for etiologic diagnosis, prevention, and intervention in AP and related conditions.

Gut microbiota interacts with inflammatory responses in acute pancreatitis

Acute pancreatitis (AP) is one of the most common acute abdominal conditions, and its incidence has been increasing for years. Approximately 15-20% of patients develop severe AP (SAP), which is complicated by critical inflammatory injury and intestinal dysfunction. AP-associated inflammation can lead to the gut barrier and function damage, causing dysbacteriosis and facilitating intestinal microbiota migration. Pancreatic exocrine deficiency and decreased levels of antimicrobial peptides in AP can also lead to abnormal growth of intestinal bacteria. Meanwhile, intestinal microbiota migration influences the pancreatic microenvironment and affects the severity of AP, which, in turn, exacerbates the systemic inflammatory response. Thus, the interaction between the gut microbiota (GM) and the inflammatory response may be a key pathogenic feature of SAP. Treating either of these factors or breaking their interaction may offer some benefits for SAP treatment. In this review, we discuss the mechanisms of interaction of the GM and inflammation in AP and factors that can deteriorate or even cure both, including some traditional Chinese medicine treatments, to provide new methods for studying AP pathogenesis and developing therapies.

Photodynamic Therapy, Probiotics, Acetic Acid, and Essential Oil in the Treatment of Chronic Wounds Infected with Pseudomonas aeruginosa

As a prevalent medical problem that burdens millions of patients across the world, chronic wounds pose a challenge to the healthcare system. These wounds, often existing as a comorbidity, are vulnerable to infections. Consequently, infections hinder the healing process and complicate clinical management and treatment. While antibiotic drugs remain a popular treatment for infected chronic wounds, the recent rise of antibiotic-resistant strains has hastened the need for alternative treatments. Future impacts of chronic wounds are likely to increase with aging populations and growing obesity rates. With the need for more effective novel treatments, promising research into various wound therapies has seen an increased demand. This review summarizes photodynamic therapy, probiotics, acetic acid, and essential oil studies as developing antibiotic-free treatments for chronic wounds infected with Pseudomonas aeruginosa. Clinicians may find this review informative by gaining a better understanding of the state of current research into various antibiotic-free treatments. Furthermore. this review provides clinical significance, as clinicians may seek to implement photodynamic therapy, probiotics, acetic acid, or essential oils into their own practice.

Characterization of Duodenal Microbiota in Patients with Acute Pancreatitis and Healthy Controls

OBJECTIVE

The small intestinal bacterial overgrowth (SIBO) in acute pancreatitis correlates with the severity of the disease. However, corresponding studies on the microbial composition of the duodenal mucosa of patients are uncommon.

METHODS

Duodenal mucosal biopsies were collected by gastroscopy from 16 patients with mild acute pancreatitis (the Ap group) and 16 healthy individuals (the control group) and subjected to histological studies as well as bacterial 16S rRNA gene sequencing. Caerulein and L-arginine were used to induce mild acute pancreatitis (MAP) and severe acute pancreatitis (SAP) in mice, respectively, and their pancreas and duodenum were collected for histological studies.

RESULTS

H&E analysis displayed no significant pathological damage in the descending duodenum of patients with acute pancreatitis compared with that of the controls. Immunofluorescence and Real-time PCR revealed that the expressions of tight junction proteins (TJPs) in duodenal mucosa were decreased in acute pancreatitis. The results of the alpha diversity analysis revealed no significant difference between the two groups, while LEfSe and the random forest revealed a few differences, indicating that the descending duodenum mucosal microbiota changed slightly in patients with mild acute pancreatitis. We observed the pathological changes and the expression of TJPs in the duodenum in the three groups of mice and found that SAP mice had more severe pathological damage in the duodenum. Furthermore, the expression of TJPs in the duodenum was lower in the MAP and SAP groups of mice compared to control mice, but it was similar in both groups.

CONCLUSION

Patients with mild acute pancreatitis had mild duodenal barrier dysfunction and slight changes in duodenal mucosal microbiota.

Lactulose regulates gut microbiota dysbiosis and promotes short-chain fatty acids production in acute pancreatitis patients with intestinal dysfunction

BACKGROUND

Intestinal dysfunction is one of the common complications in the early stage of acute pancreatitis (AP), which often associates with bad outcome. Lactulose, as a prebiotic, has been widely used to improve gut health, yet its effect on AP is unclear.

METHODS

This was a prospective, randomized trial of moderate severe AP patients complicated with intestinal dysfunction. A total of 73 participants were randomly assigned to receive either lactulose or Chinese herb rhubarb for 1 week. The primary efficacy endpoint was the recovery of intestinal function. The serum levels of inflammatory cytokines and gut barrier indexes were examined. The fecal samples from patients before and after treatment were collected. 16 S rRNA gene sequencing analysis was performed to explore the composition of gut microbiota and the amount of short-chain fatty acids (SCFAs) were detected by gas chromatography-mass spectrometry (GC-MS).

RESULTS

The intestinal dysfunction was prominently improved after 7 days of treatment with either lactulose or rhubarb. The serum levels of cytokines and gut permeability index were decreased after treatment, with stronger down-regulated degree in lactulose group than rhubarb. The potential beneficial genus Bifidobacterium was enriched in lactulose group, while pathogenic bacteria including Escherichia-Shigella and Neisseria were abundant in rhubarb group. Of note, the level of SCFAs was remarkably increased after treatment, with higher amount in lactulose group than rhubarb group.

CONCLUSIONS

Lactulose could not only restore intestinal function but also regulate gut microbiota and promote the production of SCFAs.

Polystyrene microplastics aggravate acute pancreatitis in mice

Microplastics (MPs) with a diameter of < 5mm are emerging as a new type of environmental pollutants. With the discovery of MPs in human tissues, the health risks of MPs have attracted considerable attention in recent years. In this study, we aimed to investigate the impact of MPs on acute pancreatitis (AP). We exposed male mice to 100 and 1000μg/L polystyrene MPs for 28 days, then intraperitoneally injected mice with cerulein to develop acute pancreatitis (AP). The results demonstrated that MPs dose-dependently exacerbated pancreatic injuries and inflammation in AP. High-dose MPs significantly increased intestinal barrier disruption in AP mice, which may be partly responsible for the aggravation of AP. Moreover, through tandem mass tag (TMT)- based proteomics of pancreatic tissues, we screened 101 differentially expressed proteins (DEPs) between AP mice and high-dose MPs-treated AP mice. Gene Ontology and KEGG Pathway analysis revealed that the DEPs were mainly implicated in the molecular events including cytoskeleton organization, acute inflammatory response, arginine metabolism, etc. These mechanisms may also contribute to the aggravating AP effects of MPs. Collectively, our data provide new evidence for the harmful potential of MPs.

Acute pancreatitis is characterized by generalized intestinal barrier dysfunction in early stage

BACKGROUND AND AIMS

The role of intestinal-barrier in acute pancreatitis(AP) is poorly understood. We aimed to assess structural and functional changes in the intestinal-barrier in patients with early AP (time from onset<2 weeks) and the effect of enteral nutrition on them.

METHODS

In this prospective observational study, patients with early AP not on enteral nutrition were compared with controls for baseline intestinal-permeability(lactulose: mannitol ratio(L:M)), endotoxinemia(serum IgM/IgG anti-endotoxin antibodies), bacterial-translocation(serum bacterial 16S rRNA) and duodenal epithelial tight-junction structure by immunohistochemistry(IHC) for tight-junction proteins(claudin-2,-3,-4, zonula occludens-1(ZO1), junctional adhesion molecule(JAM) and occludin) and electron microscopy. These parameters were reassessed after 2 weeks enteral feeding in a AP patients subset.

RESULTS

96 patients with AP(age: 38.0 ± 14.5 years; etiology: biliary[46.8%]/alcohol[39.6%]; severe:53.2%, mortality:11.4%) and 40 matched controls were recruited. Patients with AP had higher baseline intestinal permeability(median L:M 0.176(IQR 0.073-0.376) vs 0.049(0.024-0.075) in controls; p < 0.001) and more frequent bacteraemia(positive bacterial 16S rRNA in 24/48 AP vs 0/21 controls; p < 0.001) with trend towards higher serum endotoxinemia(median IgG anti-endotoxin 78(51.2-171.6) GMU/ml vs 51.2(26.16-79.2) in controls; p = 0.061). Claudin-2, claudin-3, ZO1 were downregulated in both duodenal crypts and villi while claudin-4 and JAM were downregulated in duodenal villi and crypts respectively. 22 AP patients reassessed after initiation of enteral nutrition showed trend towards improving intestinal permeability, serum endotoxinemia and bacteraemia, with significant improvement in claudin-2,-3 in duodenal villi.

CONCLUSION

Patients with AP have significant disturbances in intestinal barrier structure and function in first 2 weeks from onset that persist despite institution of enteral nutrition.

Toll-Like Receptor 9 Signaling Pathway Contributes to Intestinal Mucosal Barrier Injury in Mice With Severe Acute Pancreatitis

OBJECTIVES

The purpose of this study was to investigate the role and mechanism of toll-like receptor 9 (TLR9) in intestinal mucosal barrier injury in mice with severe acute pancreatitis (SAP).

METHODS

The mice were randomly divided into 3 groups: control group, SAP group, and TLR9 antagonist-treated group. The expression of tumor necrosis factor-α, interleukin-1β, interleukin-6, diamine oxidase, and endotoxin core antibodies were detected by enzyme-linked immunosorbent assay. The protein expression of zonula occluden-1 (ZO)-1, occludin, TLR9, myeloid differentiation factor 88 (MyD88), tumor necrosis factor receptor-associated factor 6 (TRAF6), p-nuclear factor (NF)-κB p65, and NF-κB p65 were detected by Western blot. TdT-mediated dUTP nick-end labeling staining was used for detecting intestinal epithelial cell apoptosis.

RESULTS

The expression of TLR9 and its related pathway proteins MyD88, TRAF6, and p-NF-κB p65 in the intestinal tract of SAP mice were significantly increased compared with that of control mice. Inhibition of the TLR9 expression could reduce the level of serum proinflammatory cytokines, reduce the apoptosis of intestinal epithelial cells, improve intestinal permeability, and ultimately reduce the damage of intestinal mucosal barrier function in SAP.

CONCLUSIONS

Toll-like receptor 9/MyD88/TRAF6/NF-κB signaling pathway plays an important role in intestinal mucosal barrier injury of SAP.

Effect of Early Continuous Veno-Venous Haemofiltration in Severe Acute Pancreatitis for the Prevention of Local Pancreatic Complications

Objective

To compare the conventional treatment and continuous veno-venous haemofiltration (CVVH) in severe acute pancreatitis (SAP) for the prevention of pseudocyst and walled-off necrosis. Patients and Methods. Forty-two patients were divided into two treatment groups: conventional treatment group contained 24 patients and CVVH had 18. Conventional treatment group patients were treated symptomatically and according to the causes. CVVH group patients were treated symptomatically, and CVVH was done within 2 hours of admission.

Results

In both groups, there was a decrease in amylase, lipase, CRP, IL-6, IL-10, TNF-alpha, Ranson score, Balthazar score, and APACHE-II score after 72 hours, but the decrease was significantly greater in CVVH patients. There were no any local pancreatic complications in CVVH patients, but 1 patient had an acute peripancreatic fluid collection, 2 patients had pseudocyst, and 2 patients had walled-off necrosis (WON), and a mortality one was seen in the conventional treatment group.

Conclusion

The present study shows that early CVVH may be able to prevent the formation of pseudocyst and win in SAP patients.

Immediate enteral nutrition can accelerate recovery and be safe in mild acute pancreatitis: A meta-analysis of randomized controlled trials

Objectives

The effect of early enteral nutrition (EN) in patients with acute pancreatitis (AP) has been confirmed. In recent years, some researchers provided new strategy that immediate EN was offered after admission. The effect and safety of immediate EN was unclear because of the different results among studies. The study aimed to implement the meta analysis of randomized controlled trials (RCT) to confirm the effect and safety between the immediate EN group and the early refeeding group.

Methods

Four electronic databases including PubMed, EMBASE, the Cochrane Library and China National Knowledge Internet (CNKI) were searched from inception to July 2021. Endnote X7.0 software was used to manage all the relevant citations. Then data extraction and evaluation of risk of bias for included studies were performed after initial selection and full-text selection. All statistical analyses were performed by Review Manager 5.3 version software.

Results

5 randomized controlled trials (RCT) involving 372 patients were included in the present study. The meta analysis revealed that immediate EN after admission in patients with AP could significantly decrease the length of hospital stay (LOHS) (Mean difference [MD] = 2.57, 95% confidence interval [CI] = 0.41–4.72) and the intolerance of feeding (risk ratio [RR] = 0.78, 95%CI = 0.63–0.95), compared with early refeeding. But immediate EN couldn't significantly decrease the incidence of readmission after discharging (RR = 0.51, 95%CI = 0.12–2.27), the incidence of progression to severe pancreatitis (RR = 0.76, 95%CI = 0.15–3.76), the incidence of complications (RR = 1.12, 95%CI = 0.50–2.49) and the values of C-reactive protein (CRP) and leukocyte counts (MD = 1.05, 95%CI = 0.15–2.26 and MD = 0.11, 95%CI = 0.59–0.80), compared with early refeeding.

Conclusions

Compared with early refeeding, immediate EN after admission could safely reduce LOHS and intolerance of feeding in patients with AP.

Gut microbiome in acute pancreatitis: A review based on current literature

The gut microbiome is a complex microbial community, recognized for its potential role in physiology, health, and disease. The available evidence supports the role of gut dysbiosis in pancreatic disorders, including acute pancreatitis (AP). In AP, the presence of gut barrier damage resulting in increased mucosal permeability may lead to translocation of intestinal bacteria, necrosis of pancreatic and peripancreatic tissue, and infection, often accompanied by multiple organ dysfunction syndrome. Preserving gut microbial homeostasis may reduce the systemic effects of AP. A growing body of evidence suggests the possible involvement of the gut microbiome in various pancreatic diseases, including AP. This review discusses the possible role of the gut microbiome in AP. It highlights AP treatment and supplementation with prebiotics, synbiotics, and probiotics to maintain gastrointestinal microbial balance and effectively reduce hospitalization, morbidity and mortality in an early phase. It also addresses novel therapeutic areas in the gut microbiome, personalized treatment, and provides a roadmap of human microbial contributions to AP that have potential clinical benefit.

Trefoil factor-2, an early predictor for acute gastrointestinal injury in patients with acute pancreatitis

Acute gastrointestinal injury (AGI) is commonly present in patients with acute pancreatitis (AP). It is often difficult to predict gastrointestinal function in the early stage due to lack of reliable markers. We aimed to assess whether early plasma trefoil factor 2 (TFF-2) is a potential predictor for AGI.Fifty one patients were included for the onset of AP (from developing abdominal pain) within 72 hours in this prospective observational single-center study from January 2013 to July 2015. Among them 23 patients were classified as mild, 17 as moderately severe, and 11 as severe according to 2012 Atlanta classification. Plasma samples were collected only once at admission to the ICU. Twenty samples of healthy adults were also collected as control. The TFF-2 levels were determined by using a human TFF-2 enzyme-linked immunoassay. AGI grades from 1st to 7th day after admission were observed.The plasma TFF-2 levels among AP patients in early stage were significantly higher than healthy controls (766.41 ng/mL vs 94.37 ng/mL, P < .0001). The correlations between TFF-2 levels and AGI grades from 1st to 4th day after admission were positive (r = 0.47, 0.43, 0.42, 0.40 respectively, P < .05). As a predictor of acute gastrointestinal failure, plasma TFF-2 was superior to others: Acute Physiology and Chronic Health Evaluation II, sequential organ failure assessment, procalcitonin, C-reactive protein, serum calcium. In addition, TFF-2 increased along with the severity of AP (r = 0.554, P < .0001) and associated with Acute Physiology and Chronic Health Evaluation II, sequential organ failure assessment, C-reactive protein, serum calcium.The plasma TFF-2 levels were increased in patients in early stage of AP and correlated with AGI grades and disease severity in our study. TFF-2 might be a potential predictor for acute gastrointestinal failure in patients with AP.

Biochemical Evaluation of the Antioxidant Effects of Hydroxytyrosol on Pancreatitis-Associated Gut Injury

Acute pancreatitis is a severe abdominal pathology often associated with several complications including gut dysfunction. Oxidative stress is one of the most important pathways involved in this pathology. Hydroxytyrosol (HT), a phenolic compound obtained from olive oil, has shown anti-inflammatory and antioxidant properties. We evaluated the effects of HT administration on pancreatic and intestinal injury induced by caerulein administration. CD1 female mice were administered caerulein (50 μg/kg) for 10 h. HT treatment (5 mg/kg) was performed 30 min after the first caerulein injection and for two consecutive hours afterwards. One hour after the last caerulein injection, mice were sacrificed and serum, colon and pancreatic tissue samples were collected. HT was able to reduce the serum hallmarks of pancreatitis (amylase and lipase), histological damage score in both pancreas and colon tissue, inflammatory cells recruitment (mast cells) in both injured tissues, intrapancreatic trypsin activity and overexpression of the adhesion molecules (Intercellular Adhesion Molecule-1 (ICAM-1) and P-selectin) in colon. Additionally, HT reduced cytokine (interleukin 1 beta (IL- 1β), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α)) levels in serum, pancreas and colon tissue and chemokine release (monocyte chemotactic protein-1 (MCP1/CCL2)) in pancreas and colon tissue. HT decreased lipid peroxidation and oxidative stress (superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) activity) by enhancing the nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) in both injured tissues. Moreover, HT preserved intestinal barrier integrity, as shown by the diamine oxidase (DAO) serum levels and tight junction (zonula occludens (ZO) and occludin) expression in pancreas and colon. Our findings demonstrated that HT would be an important therapeutic tool against pancreatitis-induced injuries in the pancreas and gut.

Confocal laser endomicroscopy reveals alterations in duodenal permeability in patients with acute pancreatitis

Objective

Intestinal permeability increases during the course of acute pancreatitis (AP). We assessed duodenal permeability alterations in patients with AP by confocal laser endomicroscopy (CLE).

Methods

Thirty patients with AP underwent CLE evaluation of the antral and duodenal mucosa. Images were graded based on the appearance of capillaries and the degree of fluorescein leakage.

Results

Patients with AP had increased duodenal mucosal permeability that could be detected by CLE. The mucosal permeability progressively increased in the gastric antrum, duodenal bulb, and descending duodenum. The CLE parameters in the antrum and duodenal bulb were not significantly different between patients with mild and severe AP. The CLE grades in the descending duodenum were higher in patients with severe than mild AP. The C-reactive protein level in AP was positively correlated with the permeability in the duodenal bulb and descending duodenum, while the computed tomography severity index score was positively correlated with the mucosal permeability in the duodenal bulb and descending duodenum.

Conclusion

CLE revealed increased duodenal permeability in patients with AP. Higher permeability in the descending duodenum was observed in severe than mild AP. Further large-scale studies are needed to confirm the relationship between altered duodenal permeability and the severity of AP.

Role of gut microbiota on intestinal barrier function in acute pancreatitis

Acute pancreatitis (AP) is a common gastrointestinal disorder. Approximately 15%-20% of patients develop severe AP. Systemic inflammatory response syndrome and multiple organ dysfunction syndrome may be caused by the massive release of inflammatory cytokines in the early stage of severe AP, followed by intestinal dysfunction and pancreatic necrosis in the later stage. A study showed that 59% of AP patients had associated intestinal barrier injury, with increased intestinal mucosal permeability, leading to intestinal bacterial translocation, pancreatic tissue necrosis and infection, and the occurrence of multiple organ dysfunction syndrome. However, the real effect of the gut microbiota and its metabolites on intestinal barrier function in AP remains unclear. This review summarizes the alterations in the intestinal flora and its metabolites during AP development and progression to unveil the mechanism of gut failure in AP.

Improving Small Intestinal Motility in Experimental Acute Necrotising Pancreatitis by Modulating the CPI-17/MLCP Pathway Using Chaiqin Chengqi Decoction

Protein kinase C-potentiated inhibitor protein of 17 kDa (CPI-17), a specific inhibitor of myosin light-chain phosphatase (MLCP) regulated by proinflammatory cytokines, is central for calcium sensitisation. We investigated the effects of chaiqin chengqi decoction (CQCQD) on the CPI-17/MLCP pathway in the small intestinal smooth muscle cells (SMCs) and strips (SMS) in an AP model. Necrotising AP was induced in rats by intraperitoneal injections (IPI) of L-ornithine (3.0 g/kg, pH 7.0; hourly × 2) at 1 hour apart; controls received saline. In treatment groups, carbachol (CCh; 60 μg/kg, IPI) or CQCQD (20 g/kg; 2-hourly × 3, intragastric) was administered. The necrotising AP model was associated with systemic inflammation (serum IL-1β and TNF-α) and worsened jejunum histopathology and motility (serum vasoactive intestinal peptide and intestinal fatty acid-binding protein) as the disease progressed. There was decreased intracellular calcium concentration ([Ca²⁺]_i) SMCs. Contractile function of isolated SMCs was reduced and associated with down-regulated expression of key mRNAs and proteins of the CPI-17/MLCP pathway as well as increased IL-1β and TNF-α. CQCQD and CCh significantly reversed these changes and the disease severity. These data suggest that CQCQD can improve intestinal motility by modulating the CPI-17/MLCP pathway in small intestinal smooth muscle during AP.

Bacterial translocation in acute pancreatitis

Bacterial translocation is a phenomenon in which live bacteria or their products cross the intestinal barrier to other organs or the circulatory system. Gut translocation of bacteria has been reported in both animal models, and clinical trials often accompany acute pancreatitis and are believed to be linked to patient outcome, especially in severe acute pancreatitis. Therefore, the mechanisms of intestinal bacterial translocation in acute pancreatitis have become a topic of interest in recent years. This review discusses Bacterial translocation in acute pancreatitis, identifies possible mechanisms of action, and provides an overview of the methods used to detect Bacterial translocation in acute pancreatitis. This review also highlights areas that require further research.

A note on error bars as a graphical representation of the variability of data in biomedical research: Choosing between standard deviation and standard error of the mean

Standard deviation and standard error of the mean have been applied widely as error bars in scientific plots. Unfortunately, there is no universally accepted principle addressing which of these two measures should be used. Here we seek to fill this gap by outlining the reasoning for choosing standard error of the mean over standard deviation and hope to shed light on this unsettled disagreement among the biomedical community. The utility of standard error of the mean and standard deviation as error bars is further discussed by examining the figures and plots published in two research articles on pancreatic disease.

Da-Cheng-Qi Decoction Alleviates Intestinal Injury in Rats with Severe Acute Pancreatitis by Inhibiting the JAK2-STAT3 Signaling Pathway

Objective

To investigate the effect of Da-Cheng-Qi decoction (DCQD) on treating intestinal injury in rats with severe acute pancreatitis (SAP), based on the Janus kinase 2 (JAK2)/signal transducers and transcription 3 (STAT3) signaling pathway.

Methods

Rats were randomly divided into the SAP group, SAP + ruxolitinib (JAK2 inhibitor) group, SAP + Stattic (STAT3 inhibitor) group, SAP + DCQD group, and sham operation group. They were further divided into 3-hour, 6-hour, 12-hour, and 18-hour subgroups. Levels of amylase and the inflammatory cytokines tumor necrosis factor-α, interleukin 6, interleukin 10, and interleukin 4 in plasma were tested. The messenger ribonucleic acid (mRNA) expression of JAK2 and STAT3 and the protein expression of phosphorylated JAK2 (p-JAK2) and phosphorylated STAT3 (p-STAT3) in the pancreas and terminal ileum tissues were examined.

Results

Rats with SAP had severe changes in plasma levels of amylase and inflammatory cytokines and showed an overexpression of JAK2 mRNA, STAT3 mRNA, p-JAK2 protein, and p-STAT3 protein in the pancreas and terminal ileum. The events could be downregulated by treatment with DCQD, JAK2 inhibitor, and STAT3 inhibitor.

Conclusions

In rats with SAP, DCQD ameliorated inflammatory cytokines and intestinal injury, which may be closely associated with the inhibition of the JAK2/STAT3 signaling pathway.

Paneth cell ablation increases the small intestinal injury during acute necrotizing pancreatitis in rats

The present work aimed to investigate the role of Paneth cells in small intestinal injury during acute necrotizing pancreatitis (ANP) using rat models established by injection of dithizone, a metal chelator of zinc with the ability to selectively ablate Paneth cells. Sprague‑Dawley rats were randomly divided into four groups: Sham‑operated group, ANP group (3.5% sodium taurocholate solution, 1 ml/kg body weight), dithizone group (100 mg/kg of body weight) and ANP + dithizone group (sodium taurocholate solution was administered 6 h after dithizone injection). Each group was further divided into five subgroups (6, 12, 24, 36 and 48 h) based on the time period between induction of the model and sample collection. The present results suggested the number of Paneth cells was gradually decreased in the ANP group in a time‑dependent manner. Most of the Paneth cells were ablated in the ANP + dithizone group at 6 h, but a subset of Paneth cells recovered after 24‑48 h. Compared with the ANP group, combination of dithizone and ANP significantly induced more severe histopathological injuries in the pancreas and distal ileum, with higher Schmidt and Chiu's scores, respectively. Additionally, increased expression levels of tumor necrosis factor‑α (TNF‑α), interleukin (IL)‑1β and IL‑17A were detected in the ileum, causing an increase in intestinal permeability, as assessed by a decrease in the expression level of the intestinal tight junction protein occludin and high plasma levels of diamine oxidase and D‑lactate. The increase in intestinal permeability led to the translocation of bacteria to the bloodstream, triggering systemic inflammation, as assessed by the increased plasma levels of TNF‑α, IL‑1β and IL‑17A, reducing the survival rates of rats, which was 66.7% and 83.3% in the ANP + dithizone and the ANP group, respectively. The increase in intestinal endoplasmic reticulum stress, as assessed by high expression levels of binding‑immunoglobulin protein and activating transcription factor 6, may be one mechanism associated with Paneth cells loss and intestinal barrier impairment during ANP. Collectively, the present study suggested that the absence of Paneth cells may be an important factor involved in intestinal injury, promoting the progression of ANP.

Gut microbiota dysbiosis worsens the severity of acute pancreatitis in patients and mice

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.

Morphological and functional impairment in the gut in a partial body irradiation minipig model of GI-ARS

Purpose: Göttingen minipig (G-MP) displays classic gastrointestinal acute radiation syndrome (GI-ARS) following total body irradiation (TBI) at GI doses which are lethal by 10-14 days. In collaboration with BARDA, we are developing a hemi-body/partial body irradiation (PBI) model by exposing only the abdomen and lower extremities to study GI structure/function impairment, natural history of injury and recovery, as well as correlative biomarkers out to 30 days.Materials and methods: Twenty-four G-MP were exposed to either 12 or 16 Gy (LINAC Elekta); head, forelimbs, and thorax were outside the irradiation field, sparing ∼50% of the bone marrow. Animals were followed for 30 days with euthanasia scheduled at pre-set intervals to study the time course of GI injury and recovery. Hematological profiles, clinical symptoms, gross- and histo-pathology including markers of proliferation and apoptosis in the small intestines, gut function parameters (food tolerance, digestion, absorption, citrulline production), and levels of two biomarkers, CRP and IGF-1, were evaluated.Results: PBI at 16 Gy yielded higher lethality than 12 Gy. Unlike TBI, PBI did not cause severe pancytopenia or external hemorrhage, as expected, and allowed to focus the injury on GI organs while sparing the radiation sensitive heart and lung. Compromised animals showed inactivity, anorexia, vomiting, diarrhea, and weight loss. Histology revealed that in 12 Gy irradiated animals, lesions recovered overtime. In 16 Gy irradiated animals, lesions were more pronounced and persistent. BrdU and Ki67 labelling demonstrated dose-dependent loss of crypts and subsequent mucosal ulceration which recovered over time. Minimal apoptosis was observed at both doses. Reductions in food tolerance, digestion, absorption, and citrulline production were time and dose-dependent. Loss of citrulline reached a nadir between 6-12 days and then recovered partially. CRP and IGF-1 were upregulated following PBI at GI doses.Conclusions: This lower hemi-body irradiation model allowed for extended survival at GI-specific ARS doses and development of a well-controlled GI syndrome with minimal hematopoietic injury or confounding mortality from cardiopulmonary damage. A dose-dependent impairment in the intestinal structure resulted in overall decreased gut functionality followed by a partial recovery. However, while the structure appeared to be recovered, not all functionality was attained. PBI induced systemic inflammation and altered the IGF-1 hormone indicating that these can be used as biomarkers in the minipig even under partial body conditions. This PBI model aligns with other minipig models under BARDA's large animal consortium to test medical countermeasure efficacy against a less complex GI-specific ARS injury.

Characterization and evolution of intestine injury at the anhepatic phase in portal hypertensive rats

The aim of the present study was to investigate the characteristics and progression of intestinal injury at the anhepatic phase in portal hypertensive rats. A total of 120 healthy male Wistar rats were purchased, with 15 rats in the normal control group and 105 rats were assigned to establish a prehepatic portal hypertension model. The 105 model rats were further divided into seven treatment groups following ischemia-reperfusion. Meanwhile, portal vein pressure, the area of lower esophageal mucosal vein, endotoxin levels in portal vein blood and the level of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured. Morphology changes of the intestine were observed using optical microscopy and transmission electron microscopy. A portal hypertension rat model was successfully established. Furthermore, endotoxin, MDA and SOD level reached a peak at 12-24 h following reperfusion and then decreased gradually to normal levels at 1 week following reperfusion. However, cytological damage did not recover to preoperative level within 1 week. These findings suggest that intestinal injury was most severe within 12-24 h following ischemia-reperfusion and most indicators recovered to almost normal levels. Therefore, further study on the intestinal mucosal damage is required, with the aim to reduce the production of intestinal endotoxin.

Intestinal Fatty Acid Binding Protein as a Marker of Necrosis and Severity in Acute Pancreatitis

OBJECTIVES

The aim of this study was to study intestinal fatty acid binding protein (i-FABP) as a potential biomarker in predicting severity of acute pancreatitis (AP).

METHODS

In a prospective multicenter cohort study, plasma levels of i-FABP were measured in 402 patients with AP. Severity of AP was determined based on the 1992 Atlanta Classification.

RESULTS

Admission levels of plasma i-FABP were significantly higher in patients with pancreatic necrosis, in patients having systemic complications, in patients treated invasively, in patients treated in the intensive care unit, in patients with severe AP, and in deceased patients. Plasma i-FABP levels on admission yielded an area under curve (AUC) of 0.732 in discriminating patients with or without pancreatic necrosis and AUC of 0.669 in predicting severe AP. Combination of levels of i-FABP and venous lactate on the day of admission showed higher discriminative power in severe AP-AUC of 0.808.

CONCLUSIONS

Higher i-FABP levels on admission were associated with pancreatic necrosis, systemic complications, and severe AP. Low levels of i-FABP had a high negative predictive value for pancreatic necrosis and severe AP. Combination of levels of i-FABP and venous lactates on admission were superior to either of markers used alone in predicting severe AP.

MiRNA-155 Regulates the Th17/Treg Ratio by Targeting SOCS1 in Severe Acute Pancreatitis

Acute pancreatitis (AP) is a serious condition associated with intestinal barrier disruption or inflammation of the pancreatic tissue. Specific microRNAs are involved in the pathogenesis of AP, during which IL-17-producing CD4⁺ T helper (Th17) cells accumulate in the pancreas. In this study, significantly increased levels of miR-155 were detected in clinical samples from patients with AP, and overexpression of miR-155 correlated with severe AP (SAP). To identify the effect of miR-155 on T cell differentiation, we isolated CD4⁺ T lymphocytes and in vitro experiments showed that inhibition of miR-155 significantly reversed the stress-induced increase in the Th17/Treg ratio. The results also showed that miR-155 increased the Th17-mediated inflammatory response by targeting SOCS1. The interaction between miR-155 and the 3^′-UTR of SOCS1 was confirmed by a dual luciferase reporter assay and RT-PCR. Experimental AP of varying severity was induced in BALB/c mice by caerulein hyperstimulation and miR-155 expression was found to increase with disease progression. Inhibition of miR-155 expression significantly improved the pathology of the pancreas. We also observed downregulation of expression of inflammatory factors, IL-17, SOCS1 and phosphorylated STAT1 after miR-155 inhibition. In summary, miR-155 regulates the Th17/Treg ratio by targeting SOCS1, most probably via direct binding to its 3^′-UTR region, indicating that this microRNA may be a potential biomarker and/or therapeutic target for AP.

Morphine worsens the severity and prevents pancreatic regeneration in mouse models of acute pancreatitis

BACKGROUND

Opioids such as morphine are widely used for the management of pain associated with acute pancreatitis. Interestingly, opioids are also known to affect the immune system and modulate inflammatory pathways in non-pancreatic diseases. However, the impact of morphine on the progression of acute pancreatitis has never been evaluated. In the current study, we evaluated the impact of morphine on the progression and severity of acute pancreatitis.

METHODS

Effect of morphine treatment on acute pancreatitis in caerulein, L-arginine and ethanol-palmitoleic acid models was evaluated after induction of the disease. Inflammatory response, gut permeability and bacterial translocation were compared. Experiments were repeated in mu (µ) opioid receptor knockout mice (MORKO) and in wild-type mice in the presence of opioid receptor antagonist naltrexone to evaluate the role of µ-opioid receptors in morphine's effect on acute pancreatitis. Effect of morphine treatment on pathways activated during pancreatic regeneration like sonic Hedgehog and activation of embryonic transcription factors like pdx-1 and ptf-1 were measured by immunofluorescence and quantitative PCR.

RESULTS

Histological data show that treatment with morphine after induction of acute pancreatitis exacerbates the disease with increased pancreatic neutrophilic infiltration and necrosis in all three models of acute pancreatitis. Morphine also exacerbated acute pancreatitis-induced gut permeabilisation and bacteraemia. These effects were antagonised in the MORKO mice or in the presence of naltrexone suggesting that morphine's effect on severity of acute pancreatitis are mediated through the µ-opioid receptors. Morphine treatment delayed macrophage infiltration, sonic Hedgehog pathway activation and expression of pdx-1 and ptf-1.

CONCLUSION

Morphine treatment worsens the severity of acute pancreatitis and delays resolution and regeneration. Considering our results, the safety of morphine for analgesia during acute pancreatitis should be re-evaluated in future human studies.

Chai-Qin-Cheng-Qi Decoction and Carbachol Improve Intestinal Motility by Regulating Protein Kinase C-Mediated Ca2+ Release in Colonic Smooth Muscle Cells in Rats with Acute Necrotising Pancreatitis

Chai-Qin-Cheng-Qi decoction (CQCQD) improves intestinal motility in acute pancreatitis (AP), but the mechanism(s) require elucidation. We investigated the effects of CQCQD and carbachol, a prokinetic agent, on colonic smooth muscle cells (SMCs) in L-arginine-induced necrotising AP model in rats. In treatment groups, intragastric CQCQD (20 g/kg, 2 hourly × 3 doses) or intraperitoneal carbachol (60 μg/kg) was given 24 hours after induction of AP. Both CQCQD and carbachol decreased the severity of pancreatic and colonic histopathology (all P < 0.05). Both CQCQD and carbachol reduced serum intestinal fatty acid binding protein, vasoactive intestinal peptide, and substance P and increased motility levels. CQCQD upregulated SMC phospholipase C-beta 1 (PLC-β1) mRNA and PLC protein (both P < 0.05), while both treatments upregulated protein kinase C-alpha (PKC-α) mRNA and PKC protein and downregulated adenylate cyclase (AC) mRNA and protein compared with no treatment (all P < 0.05). Neither treatment significantly altered L-arginine-induced PKC-β1 and PKC-ε mRNA reduction. Both treatments significantly increased fluorescence intensity of SMC intracellular calcium concentration [Ca²⁺]_i (3563.5 and 3046.9 versus 1086.9, both P < 0.01). These data suggest CQCQD and carbachol improve intestinal motility in AP by increasing [Ca²⁺]_i in colonic SMCs via upregulating PLC, PKC and downregulating AC.

X-ray guided placement of Freka Trelumina using a guide wire for treatment of acute pancreatitis

AIM

To assess the efficacy of X-ray guided placement of Freka Trelumina using a guide wire in the treatment of early acute pancreatitis.

METHODS

One hundred and sixty acute pancreatitis patients were randomly divided into either a treatment group or a control group. The treatment group received X-ray guided placement of Freka Trelumina using a guide wire, while the control group received regular stomach tube and spiral nasoenteric feeding tube placement. The duration of placement, success rate, degree of tolerance when placing and after placing, serum levels of high sensitive C-reactive protein and albumin, gastrointestinal symptoms, time to recovery of enteric function, and hospital stay were compared between the two groups.

RESULTS

The treatment group showed significantly improved results in terms of duration of placement, success rate, and degree of tolerance compared to the control group. The rate of gastrointestinal symptoms was significantly lower and the time to recovery of enteric function was significantly shorter in the treatment group. On day 7 of hospital stay, the level of high sensitive C-responsive protein was significantly lower in the treatment group than in the control group, and serum albumin level recovered faster in the treatment group. Hospital stay was also shorter in the treatment group.

CONCLUSION

X-ray guided placement of Freka Trelumina has a positive effect on the treatment of early acute pancreatitis. This treatment requires shorter operation time and has a higher success rate and better tolerance, and it could shorten hospital stay and improve prognosis.

Low-methoxyl lemon pectin attenuates inflammatory responses and improves intestinal barrier integrity in caerulein-induced experimental acute pancreatitis

SCOPE

Acute pancreatitis (AP) is a common clinical acute abdominal disease. The intestinal injury associated with AP will aggravate the condition retroactively. This study investigates whether the low-methoxyl pectin (LMP) isolated from lemon could attenuate AP and associated intestinal injury.

METHODS AND RESULTS

Experimental AP was induced in BALB/c mice by caerulien (CAE) hyperstimulation. Nutritional prophylactic group was pre-fed with 5% LMP supplemented forage 3 days before AP induction. We found that LMP supplementation attenuated the severity of AP as evidenced by reduced serum amylase and lipase levels, pancreatic edema and myeloperoxidase activity. The protective effect was also confirmed by histological examination of pancreatic damage. LMP suppressed the production of pancreatic proinflammatory cytokines including TNF-α, IL-1β, and IL-6. Moreover, LMP supplementation restored AP-associated disruption of intestinal barrier integrity as evidenced by upregulation of tight junction modulatory proteins occludin, zonula occludens (ZO)-1, antimicrobial peptides β-defensin-1 (DEFB1) and CRAMP as well as increase in SCFAs production. LMP supplemented mice with AP exhibited suppressed intestinal inflammation as shown by decreased ileal and colon cytokine production compared with CAE group.

CONCLUSION

Our results support dietary LMP supplementation as an effective nutritional intervention for AP and associated intestinal injury.

Lung Inflammation Associated With Clinical Acute Necrotizing Pancreatitis in Dogs

Although dogs with acute necrotizing pancreatitis (ANP) can develop respiratory complications, there are no data describing lung injury in clinical cases of ANP in dogs. Therefore, we conducted a study to characterize lung injury and determine if pulmonary intravascular macrophages (PIMs) are induced in dogs with ANP ( n = 21) compared with control dogs ( n = 6). Two pathologists independently graded histologic sections of pancreas from clinical cases to characterize the severity of ANP (total scores of 3–10) compared with controls showing histologically normal pancreas (total scores of 0). Based on histological grading, lungs from dogs with ANP showed inflammation (median score, 1.5; range, 0–3), but the scores did not differ statistically from the control lungs (median score, 0.5; range, 0–2). A grid intersects-counting method showed an increase in the numbers of MAC387-positive alveolar septal mononuclear phagocyte profiles in lungs of dogs with ANP (ratio median, 0.0243; range, 0.0093–0.0734, with 2 outliers at 0.1523 and 0.1978) compared with controls (ratio median, 0.0019; range, 0.0017–0.0031; P < .0001). Only dogs with ANP showed labeling for von Willebrand factor in alveolar septal capillary endothelial cells, septal inflammatory cells, and alveolar macrophages. Toll-like receptor 4 and interleukin 6 were variably expressed in alveolar macrophages and septal inflammatory cells in lungs from both ANP and control dogs. Inducible nitric oxide synthase was detected in alveolar macrophages of dogs with ANP only. These data show that dogs with ANP have lung inflammation, including the recruitment of PIMs and expression of inflammatory mediators.

Early enteral nutrition improves intestinal immune barrier in a rat model of severe acute pancreatitis

BACKGROUND

The aim of the present study was to investigate the role of early enteral nutrition (EEN) in the intestinal immune barrier in severe acute pancreatitis (SAP), and to explore its potential mechanisms.

METHODS

Sixty rats were randomly assigned to three groups: sham-operated group (SO group, n = 20), SAP group receiving EEN (SAP + EEN group, n = 20), and SAP group receiving total parental nutrition (SAP + TPN group, n = 20). SAP was induced by infusion of sodium taurocholate. Rats were killed 5 days after nutritional support. The pathological damage of the intestine was determined using HE staining. The expression of MAdCAM-1, CD⁴⁺ , and CD⁸⁺ in Peyer's lymph nodes of the distal ilium was examined by immunohistochemistry. Serum levels of endotoxin and bacterial translocation were determined.

RESULTS

The survival rate in the SAP + TPN (50%) and SAP + EEN (75%) groups was significantly lower than in the SO group (100%) (P < 0.05). The survival rate in the SAP + EEN group was significantly higher than in the SAP + TPN group (P < 0.05). The expression of MAdCAM-1, CD⁴⁺ and CD⁸⁺ in the intestine was decreased in SAP rats. EEN significantly increased the expression of MAdCAM-1, CD⁴⁺ and CD⁸⁺ compared with TPN, accompanied by a decrease in the serum levels of endotoxin and bacterial translocation.

CONCLUSIONS

Early enteral nutrition improves intestinal immune barrier, thus reducing bacterial and endotoxin translocation and improving the survival rate in SAP rats.

Severity of pancreatitis‑associated intestinal mucosal barrier injury is reduced following treatment with the NADPH oxidase inhibitor apocynin

Recent studies demonstrated that apocynin, a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) inhibitor, significantly decreased acute pancreatitis-associated inflammatory and oxidative stress parameters. In addition, apocynin was able to reduce ischemic reperfusion injury-associated damage; however, the exact effects of apocynin on acute pancreatitis-associated intestinal mucosal injury have yet to be fully clarified. The present study aimed to investigate the protective effects of apocynin on intestinal mucosal injury in a rat model of severe acute pancreatitis (SAP). A total of 60 male Sprague Dawley rats were randomly divided into four groups (n=15/group): Sham operation group (SO), SAP group, apocynin treatment (APO) group and drug control (APO-CON) group. SAP was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. Apocynin was administered 30 min prior to SAP induction in the APO group. All rats were sacrificed 12 h after SAP induction. Intestinal integrity was assessed by measuring diamine oxidase (DAO) levels. Morphological alterations to intestinal tissue were determined under light and transmission electron microscopy. NOX2, p38 mitogen-activated protein kinases (MAPK) and nuclear factor (NF)-κB expression levels were detected in the intestine by immunohistochemical staining. Oxidative stress was detected by measuring intestinal malondialdehyde (MDA) and superoxide dismutase content. In addition, blood inflammatory cytokines, and amylase (AMY) and lipase (LIP) levels were evaluated. The results demonstrated that apocynin attenuated the following: i) Serum AMY, LIP and DAO levels; ii) pancreatic and intestinal pathological injury; iii) intestinal MDA content; iv) intestinal ultrastructural alterations; v) serum interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α levels; and vi) NOX2, p38 MAPK and NF-κB expression in intestinal tissues. These results suggested that apocynin may attenuate intestinal barrier dysfunction in sodium taurocholate-induced SAP, presumably via its role in the prevention of reactive oxygen species generation and inhibition of p38 MAPK and NF-κB pathway activation. These findings provide novel insight suggesting that pharmacological inhibition of NOX by apocynin may be considered a novel therapeutic method for the treatment of intestinal injury in SAP.

Pathophysiological mechanisms in acute pancreatitis: Current understanding

The precise mechanisms involved in the pathophysiology of acute pancreatitis (AP) are still far from clear. Several earlier studies have focused mainly on pancreatic enzyme activation as the key intracellular perturbation in the pancreatic acinar cells. For decades, the trypsin-centered hypothesis has remained the focus of the intra-acinar events in acute pancreatitis. Recent advances in basic science research have lead to the better understanding of various other mechanisms such as oxidative and endoplasmic stress, impaired autophagy, mitochondrial dysfunction, etc. in causing acinar cell injury. Despite all efforts, the clinical outcome of patients with AP has not changed significantly over the years. This suggests that the knowledge of the critical molecular pathways in the pathophysiology of AP is still limited. The mechanisms through which the acinar cell injury leads to local and systemic inflammation are not well understood. The role of inflammatory markers and immune system activation is an area of much relevance from the point of view of finding a target for therapeutic intervention. Some data are available from experimental animal models but not much is known in human pancreatitis. This review intends to highlight the current understanding in this area.

Acute pancreatitis: international classification and nomenclature

The incidence of acute pancreatitis (AP) is increasing and it is associated with a major healthcare concern. New insights in the pathophysiology, better imaging techniques, and novel treatment options for complicated AP prompted the update of the 1992 Atlanta Classification. Updated nomenclature for pancreatic collections based on imaging criteria is proposed. Adoption of the newly Revised Classification of Acute Pancreatitis 2012 by radiologists should help standardise reports and facilitate accurate conveyance of relevant findings to referring physicians involved in the care of patients with AP. This review will clarify the nomenclature of pancreatic collections in the setting of AP.

Dysbiosis of Intestinal Microbiota Associated With Inflammation Involved in the Progression of Acute Pancreatitis

OBJECTIVES

To evaluate alterations of the intestinal bacteria and its associations with the inflammation in acute pancreatitis (AP).

METHODS

A multihospital prospective clinical study was conducted, and a total of 108 participants were enrolled in our study, including 44 with severe AP (SAP), 32 with mild AP (MAP), and 32 healthy volunteers. The structure of intestinal microbiota, 10 predominant bacteria, plasma endotoxin, and serum cytokines were investigated by polymerase chain reaction-denaturing gradient gel electrophoresis, real-time quantitative polymerase chain reaction, Limulus amebocyte lysate tests, and enzyme-linked immunosorbent assays, respectively.

RESULTS

Dramatic alterations in the predominant fecal microbiota were observed in most of both MAP and SAP patients. In addition, the rates of the multiorgan failures and infectious complications in the patients with SAP with altered intestinal microbiota were significantly higher than in those whose intestinal microbiota remained unaltered. Enterococcus increased and Bifidobacterium decreased in the patients with SAP compared to the patients with MAP. Serum IL-6 were positively correlated with Enterobacteriaceae and Enterococcus and negatively correlated with Bifidobacterium, whereas plasma endotoxin positively correlated with Enterococcus (P < 0.05).

CONCLUSIONS

The intestinal bacteria most frequently altered in both the patients with MAP and those with SAP significantly correlated with inflammation, which indicated that the intestinal microbiota may be involved in the progression of AP.

Endoplasmic reticulum stress may not be involved in intestinal epithelial cell apoptosis in experimental acute pancreatitis

OBJECTIVES

To investigate whether endoplasmic reticulum (ER) stress is activated in the intestinal epithelium of acute pancreatitis (AP), and whether it is one of the inducing factors of the intestinal epithelial cell apoptosis in AP.

METHODS

Twenty-four rats were randomly divided into two groups. AP was induced via retrograde injection of 3 % sodium taurocholate into the pancreatic duct. As a control group, rats received a sham operation. Forty-eight hours after the operation, the ultrastructural changes of ileal epithelial cells were investigated by transmission electron microscope. The protein expressions of GRP78, CHOP, caspase-12, and JNK in the ileal epithelium were determined by immunohistochemistry, and apoptosis was determined by TdT-mediated dUTP nick end labeling. The mRNA expressions of GRP78, CHOP, caspase-12, and JNK in the ileal epithelium were determined using quantitative RT-PCR.

RESULTS

The ileal epithelium in rats with AP had significantly higher apoptotic cells compared with that of the control rats (P < 0.05). ER stress was activated in the ileal epithelium, which was characterized by dilated, irregular ER and upregulated expressions of GRP78 mRNA and protein. The mRNA and protein expressions of CHOP, caspase-12, and JNK in rats with AP were similar to that in the control rats (P > 0.05).

CONCLUSIONS

ER stress is induced in intestinal epithelium during AP; however, ER stress is not likely to be involved in the apoptosis of the intestinal epithelium during AP.

Inflammasomes in pancreatic physiology and disease

In this review we summarize the role of inflammasomes in pancreatic physiology and disease with a focus on acute pancreatitis where much recent progress has been made. New findings have identified inducers of and cell specificity of inflammasome component expression in the pancreas, the contribution of inflammasome-regulated effectors to pancreatitis, and metabolic regulation of inflammasome activation, which are strong determinants of injury in pancreatitis. New areas of pancreatic biology will be highlighted in the context of our evolving understanding of gut microbiome- and injury-induced inflammasome priming, pyroptosis, and innate immune-mediated regulation of cell metabolism.

Risk factors of refeeding intolerance in mild acute interstitial pancreatitis: a retrospective study of 323 patients

OBJECTIVES

This study was aimed to access the frequency and identify independent risk factors of refeeding intolerance in patients with mild acute interstitial pancreatitis.

MATERIALS AND METHODS

Patients with mild acute pancreatitis (AP) were included in this observational, descriptive, and retrospective study. Clinical variables, therapy-related variables, and biochemical and radiological variables were analyzed by univariate and multivariate analysis.

RESULTS

Of 323 included cases, 40 patients (12.4%) developed refeeding intolerance. In the final regression model, hypertriglyceridemia-induced AP (odds ratio, 7.72; 95% CI: 2.50-23.82, P < 0.001), elevated serum lipase (>2-fold of the upper limit of normal) before refeeding (odds ratio, 2.13; 95% CI: 1.2-3.77, P = 0.009), and immediate feeding (odds ratio, 1.75; 95% CI: 1.31-2.33, P < 0.001) were critical risk factors of refeeding intolerance.

CONCLUSION

Refeeding intolerance occurs in 12.4% patients with mild AP and appears more often in those with hypertriglyceridemia-induced AP, elevated serum lipase (>2-fold of the upper limit of normal) before refeeding, and immediate feeding.

Roles of Commensal Microbiota in Pancreas Homeostasis and Pancreatic Pathologies

The pancreas plays a central role in metabolism, allowing ingested food to be converted and used as fuel by the cells throughout the body. On the other hand, the pancreas may be affected by devastating diseases, such as pancreatitis, pancreatic adenocarcinoma (PAC), and diabetes mellitus (DM), which generally results in a wide metabolic imbalance. The causes for the development and progression of these diseases are still controversial; therefore it is essential to better understand the underlying mechanisms which compromise the pancreatic homeostasis. The interest in the study of the commensal microbiome increased extensively in recent years, when many discoveries have illustrated its central role in both human physiology and maintenance of homeostasis. Further understanding of the involvement of the microbiome during the development of pathological conditions is critical for the improvement of new diagnostic and therapeutic approaches. In the present review, we discuss recent findings on the behavior and functions played by the microbiota in major pancreatic diseases and provide further insights into its potential roles in the maintenance of pancreatic steady-state activities.

Role of high mobility group box-1 and protection of growth hormone and somatostatin in severe acute pancreatitis

In this study, we investigated the potential role of high-mobility group box 1 (HMGB1) in severe acute pancreatitis (SAP) and the effects of growth hormone (G) and somatostatin (S) in SAP rats. The rats were randomly divided into 6 groups of 20 each: sham-operated, SAP, SAP+saline, SAP+G, SAP+S and SAP+G+S. Ileum and pancreas tissues of rats in each group were evaluated histologically. HMGB1 mRNA expression was measured by reverse transcription-PCR. Levels of circulating TNF-α, IL-1, IL-6, and endotoxin were also measured. In the SAP group, interstitial congestion and edema, inflammatory cell infiltration, and interstitial hemorrhage occurred in ileum and pancreas tissues. The levels of HMGB1, TNF-α, IL-1, IL-6 and endotoxin were significantly up-regulated in the SAP group compared with those in the sham-operated group, and the 7-day survival rate was 0%. In the SAP+G and SAP+S groups, the inflammatory response of the morphological structures was alleviated, the levels of HMGB1, TNF-α, IL-1, IL-6, and endotoxin were significantly decreased compared with those in the SAP group, and the survival rate was increased. Moreover, in the SAP+G+S group, all histological scores were significantly improved and the survival rate was significantly higher compared with the SAP group. In conclusion, HMGB1 might participate in pancreas and ileum injury in SAP. Growth hormone and somatostatin might play a therapeutic role in the inflammatory response of SAP.