Surveillance of intra-abdominal pressure and intestinal barrier function in a rat model of acute necrotizing pancreatitis and its potential early therapeutic window

LncRNA446 Regulates Tight Junctions by Inhibiting the Ubiquitinated Degradation of Alix after Porcine Epidemic Diarrhea Virus Infection

Porcine epidemic diarrhea (PED) is a highly contagious disease, caused by porcine epidemic diarrhea virus (PEDV), which causes huge economic losses. Tight junction-associated proteins play an important role during virus infection; therefore, maintaining their integrity may be a new strategy for the prevention and treatment of PEDV. Long noncoding RNAs (lncRNAs) participate in numerous cellular functional activities, yet whether and how they regulate the intestinal barrier against viral infection remains to be elucidated. Here, we established a standard system for evaluating intestinal barrier integrity and then determined the differentially expressed lncRNAs between PEDV-infected and healthy piglets by lncRNA-seq. A total of 111 differentially expressed lncRNAs were screened, and lncRNA446 was identified due to significantly higher expression after PEDV infection. Using IPEC-J2 cells and intestinal organoids as in vitro models, we demonstrated that knockdown of lncRNA446 resulted in increased replication of PEDV, with further damage to intestinal permeability and tight junctions. Mechanistically, RNA pulldown and an RNA immunoprecipitation (RIP) assay showed that lncRNA446 directly binds to ALG-2-interacting protein X (Alix), and lncRNA446 inhibits ubiquitinated degradation of Alix mediated by TRIM25. Furthermore, Alix could bind to ZO1 and occludin and restore the expression level of the PEDV M gene and TJ proteins after lncRNA446 knockdown. Additionally, Alix knockdown and overexpression affects PEDV infection in IPEC-J2 cells. Collectively, our findings indicate that lncRNA446, by inhibiting the ubiquitinated degradation of Alix after PEDV infection, is involved in tight junction regulation. This study provides new insights into the mechanisms of intestinal barrier resistance and damage repair triggered by coronavirus. IMPORTANCE Porcine epidemic diarrhea is an acute, highly contagious enteric viral disease severely affecting the pig industry, for which current vaccines are inefficient due to the high variability of PEDV. Because PEDV infection can lead to severe injury of the intestinal epithelial barrier, which is the first line of defense, a better understanding of the related mechanisms may facilitate the development of new strategies for the prevention and treatment of PED. Here, we demonstrate that the lncRNA446 directly binds one core component of the actomyosin-tight junction complex named Alix and inhibits its ubiquitinated degradation. Functionally, the lncRNA446/Alix axis can regulate the integrity of tight junctions and potentially repair intestinal barrier injury after PEDV infection.

Effect of Clostridium butyricum and Butyrate on Intestinal Barrier Functions: Study of a Rat Model of Severe Acute Pancreatitis With Intra-Abdominal Hypertension

BACKGROUND/AIMS

Severe acute pancreatitis (SAP) is associated with intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS), but treatment of these conditions is difficult. We studied a rat model of SAP + IAH to determine the effect of oral administration of Clostridium butyricum and butyrate (its major metabolite) on intestinal barrier functions.

METHODS

A total of 48 rats were assigned to four groups, with 12 rats per group: Sham, SAP+IAH, SAP+IAH+C. butyricum, and SAP + IAH + butyrate. SAP was induced by sodium taurocholate infusion into the biliopancreatic duct, intra-abdominal pressure (IAP), mortality was measured 24 h later, and then rats were euthanized. The plasma levels of several markers [amylase, diamine oxidase (DAO), fluorescein isothiocyanate (FITC)-dextran, tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-1β, IL-12, lipopolysaccharide (LPS)] and fecal butyric acid level were determined. The pancreas and intestine were examined using histology, and RT-PCR and Western blotting of intestinal tissues were used to measure the expression of six markers {tight junction proteins [zonula occludens protein-1 (ZO-1), claudin-1, claudin-2, occluding], matrix metalloproteinase 9 [MMP9], and TNF-α}. The gut flora of the rats was examined by 16S rRNA sequencing.

RESULTS

Induction of SAP + IAH altered several functions of the intestinal barrier, and enhanced intestinal permeability, decreased the levels of ZO-1, claudin-1, occludin, the richness and diversity of the microflora community, the relative abundance (RA) of Firmicutes, and the number of probiotic organisms. However, induction of SAP+IAH increased the expression of claudin-2, MMP9, and TNF-α, and the RA of Proteobacteria and pathogens in the feces. Rats that received oral C. butyricum or butyrate had reduced intestinal injury and plasma levels of DAO, LPS, and inflammatory cytokines.

CONCLUSION

This study of rats with SAP+IAH indicated that oral dosing of C. butyricum or butyrate reduced intestinal injury, possibly by altering the functions of the intestinal mucosal barrier.

Machine Learning Models of Acute Kidney Injury Prediction in Acute Pancreatitis Patients

Background. Acute kidney injury (AKI) has long been recognized as a common and important complication of acute pancreatitis (AP). In the study, machine learning (ML) techniques were used to establish predictive models for AKI in AP patients during hospitalization. This is a retrospective review of prospectively collected data of AP patients admitted within one week after the onset of abdominal pain to our department from January 2014 to January 2019. Eighty patients developed AKI after admission (AKI group) and 254 patients did not (non-AKI group) in the hospital. With the provision of additional information such as demographic characteristics or laboratory data, support vector machine (SVM), random forest (RF), classification and regression tree (CART), and extreme gradient boosting (XGBoost) were used to build models of AKI prediction and compared to the predictive performance of the classic model using logistic regression (LR). XGBoost performed best in predicting AKI with an AUC of 91.93% among the machine learning models. The AUC of logistic regression analysis was 87.28%. Present findings suggest that compared to the classical logistic regression model, machine learning models using features that can be easily obtained at admission had a better performance in predicting AKI in the AP patients.

Gastrointestinal Failure Is a Predictor of Poor Outcome in Patients with Acute Pancreatitis

OBJECTIVE

Although gastrointestinal dysfunction is common in patients with acute pancreatitis, its impact on the outcome of disease has not been adequately studied. The present study was conducted to study the frequency of gastrointestinal failure (GIF) as well as its effect on outcome in patients with acute pancreatitis.

METHODS

Patients with acute pancreatitis admitted in our unit were prospectively studied. Gastrointestinal dysfunction and intra-abdominal pressures were measured daily till their resolution, and gastrointestinal failure score was calculated. Baseline parameters including various severity scores were noted. The patients were followed till clinical recovery or death.

RESULTS

Sixty-four patients (mean age 41.52 ± 16.28 years; 45 (70.3%) males) were prospectively studied. Forty-five (70.3%) patients had severe disease, and 18 (28.1%) patients succumbed to illness. GIF was present in 31 (48.4%) patients. The median duration of GIF was 5 (range 1-20) days. The presence of GIF was significantly associated with mortality (p value < 0.05). On multivariate analysis, the presence of GIF [OR 10.6 (95% CI 1.97-57.04)] and duration of ICU stay [OR 1.08 (95% CI 1.015-1.15)] were found to be independent predictors of mortality.

CONCLUSION

Gastrointestinal failure is an important organ failure in patients with acute pancreatitis and is an independent predictor of mortality. Incorporation of gastrointestinal failure scores in dynamic assessment of patients with acute pancreatitis could help us in better stratifying severity of patients and predicting outcome.

The Liver and Small Intestine Can Partly Compensate Severe Normovolemic Hemodilution in a Rat Model

BACKGROUND

Knowing the individual critical hematocrit for every organ is essential in operative scenarios in which extensive blood losses are expected. In the past, experimental settings were very heterogeneous resulting in the publication of widely differing values even for one organ in the same species. This study aimed to investigate the compensatory capacity of the liver and the small intestine in a rat model of severe normovolemic hemodilution.

MATERIALS AND METHODS

Male rats were subjected to a stepwise hemodilution with a succinylated gelatin-containing solution to a final hematocrit of 10%, being observed for additional 150 min. During the course of the experiment, blood glucose and L-lactate, as well as D-lactate and intestinal fatty acid-binding protein-2 measurements, were performed eight times in total. The amino acids alanine and glutamine were measured during dilution and at the end of the experiment (four times in total). Hemodilutional effects on the blood and oxygen supply of the liver and the small intestine were measured in a minimally invasive manner.

RESULTS

In the liver and the small intestine, there were no substantial changes in the blood flow of the microcirculation. Plasma glucose and lactate levels rose transiently, whereas lactate values did not exceed the upper threshold of aerobic metabolism. Plasma levels of the amino acids alanine and glutamine rose significantly and stayed elevated, whereas D-lactate and intestinal fatty acid-binding protein-2 were not significantly increased at any point during the whole experimental time compared to the initial value.

CONCLUSIONS

Severe hemodilution with a succinylated gelatin-containing solution is tolerated at a profoundly low hematocrit value of 10% during the experimental phase of 150 min.

Intra-abdominal pressure: Time ripe to revise management guidelines of acute pancreatitis?

AIM

To systematically review evidence on pathophysiology of intra-abdominal pressure (IAP) in acute pancreatitis (AP) with its clinical correlates.

METHODS

Systematic review of available evidence in English literature with relevant medical subject heading terms on PubMed, Medline and Scopus with further search from open access sources on internet as suggested by articles retrieved.

RESULTS

Intra-abdominal hypertension (IAH) is increasingly gaining recognition as a point of specific intervention with potential to alter disease outcome and improve mortality in AP. IAH can be expected in at least 17% of patients presenting with diagnosis of AP to a typical tertiary care hospital (prevalence increasing to 50% in those with severe disease). Abdominal compartment syndrome can be expected in at least 15% patients with severe disease. Recent guidelines on management of AP do not acknowledge utility of surveillance for IAP other than those by Japanese Society of Hepato-Biliary-Pancreatic Surgery. We further outline pathophysiologic mechanisms of IAH; understanding of which advances our knowledge and helps to coherently align common observed variations in management related conundrums (such as fluid therapy, nutrition and antibiotic prophylaxis) with potential to further individualize treatment in AP.

CONCLUSION

We suggest that IAP be given its due place in future practice guidelines and that recommendations be formed with help of a broader panel with inclusion of clinicians experienced in management of IAH.

Effects of lactadherin on plasma D-lactic acid and small intestinal MUC2 and claudin-1 expression levels in rats with rotavirus-induced diarrhea

The aim of the present study was to investigate the effects of lactadherin on plasma D-lactic acid and small intestinal mucin (MUC) 2 and claudin-1 expression levels in rats with diarrhea induced by rotavirus (RV) infection. A total of 75 seven-day-old healthy Sprague-Dawley rats were randomly divided into the following five groups: Control (C), RV infection (RVI), lactadherin before rotavirus infection (LBRI), lactadherin after rotavirus infection (LARI), and blank (B). On day 4 of artificial feeding, the rats in groups RVI, LBRI and LARI were intragastric administered 1×106 PFU RV; whereas the rats in groups C and B were intragastrically administered an equal volume of maintenance solution from the RV supernatant and normal saline, respectively. In the LBRI and LARI groups, rats received daily intragastric administration of 0.25 mg lactadherin for three days prior to and following infection with RV, respectively. The course of diarrheal symptoms was observed in each group and samples were collected on days 1, 4, and 7 post-infection in order to determine the mucosal morphology, plasma D-lactic acid levels and the expression levels of MUC2 and the intracellular junction protein, claudin-1, in the small intestine. On day 4 post-infection, the rats in group RVI demonstrated severely damaged small intestines and typical diarrheal characteristics, as detected by light microscopy; whereas rats in groups LBRI and LARI demonstrated intact small intestinal villi with partial vacuolation of epithelial cells and changes in the position of their nuclei. Electron microscopy demonstrated that the rats in the RVI group had sparse, shortened, disordered intestinal microvilli and widened intercellular junctions; whereas those in groups LBRI and LARI had long intestinal microvilli sparser compared with groups B and C and slightly widened intercellular junctions. Plasma D-lactic acid levels were increased in groups RVI, LBRI and LARI, as compared with groups B and C, and the greatest levels were detected in the RVI group on days 1, 4 and 7 post-infection. In addition to maintaining intestinal permeability, lactadherin enhanced the expression levels of MUC2 and reduced the expression of claudin-1; therefore, further protecting the intestinal epithelial barrier, which may contribute to the prevention and treatment of diarrhea induced by infection with RV.

The effect of peritoneal air exposure on intestinal mucosal barrier

Background. Damage of the intestinal mucosa barrier may result in intestinal bacterial and endotoxin translocation, leading to local and systemic inflammation. The present study was designed to investigate whether peritoneal air exposure induces damage of intestinal mucosal barrier. Methods. Sprague-Dawley rats (weighing 210 to 230 g) were randomized into five groups (6/group): a control group, a sham group, and three exposure groups with peritoneal air exposure for 1, 2, and 3 h, respectively. At 24 h after surgery, blood and terminal ileum were sampled. The serum D-lactate levels were determined using an ELISA kit. The intestinal permeability was determined by measuring the intestinal clearance of FITC-dextran (FD4). The histopathological changes in terminal ileum were also assessed. Results. Compared with the controls, peritoneal air exposure caused an increase in both serum D-lactate level and intestinal FD4 clearance, which were proportional to the length of peritoneal air exposure and correlated to Chiu's scores, indices for intestinal mucosal injury. Edema and inflammatory cells were also observed in mucosa and submucosa of ileum in three exposure groups. Conclusions. Peritoneal air exposure could induce damage to the intestinal mucosal barrier, which is proportional to the time length of peritoneal air exposure.