Heavy metals in cigarette smoke strongly inhibit pancreatic ductal function and promote development of chronic pancreatitis.

BACKGROUND AND AIMS: Smoking is recognised as an independent risk factor in the development of chronic pancreatitis (CP). Cystic fibrosis transmembrane conductance regulator (CFTR) function and ductal fluid and bicarbonate secretion are also known to be impaired in CP, so it is crucial to understand the relationships between smoking, pancreatic ductal function and the development of CP. METHODS: We measured sweat chloride (Cl-) concentrations in patients with and without CP, both smokers and non-smokers, to assess CFTR activity. Serum heavy metal levels and tissue cadmium concentrations were determined by mass spectrometry in smoking and non-smoking patients. Guinea pigs were exposed to cigarette smoke, and cigarette smoke extract (CSE) was prepared to characterise its effects on pancreatic HCO3 - and fluid secretion and CFTR function. We administered cerulein to both the smoking and non-smoking groups of mice to induce pancreatitis. RESULTS: Sweat samples from smokers, both with and without CP, exhibited elevated Cl- concentrations compared to those from non-smokers, indicating a decrease in CFTR activity due to smoking. Pancreatic tissues from smokers, regardless of CP status, displayed lower CFTR expression than those from non-smokers. Serum levels of cadmium and mercury, as well as pancreatic tissue cadmium, were increased in smokers. Smoking, CSE, cadmium, mercury and nicotine all hindered fluid and HCO3 - secretion and CFTR activity in pancreatic ductal cells. These effects were mediated by sustained increases in intracellular calcium ([Ca2+]i), depletion of intracellular ATP (ATPi) and mitochondrial membrane depolarisation. CONCLUSION: Smoking impairs pancreatic ductal function and contributes to the development of CP. Heavy metals, notably cadmium, play a significant role in the harmful effects of smoking. KEY POINTS: Smoking and cigarette smoke extract diminish pancreatic ductal fluid and HCO3 - secretion as well as the expression and function of CFTR Cd and Hg concentrations are significantly higher in the serum samples of smokers Cd accumulates in the pancreatic tissue of smokers.

The anti-inflammatory effect of dimethyl trisulfide in experimental acute pancreatitis.

Various organosulfur compounds, such as dimethyl trisulfide (DMTS), display anti-inflammatory properties. We aimed to examine the effects of DMTS on acute pancreatitis (AP) and its mechanism of action in both in vivo and in vitro studies. AP was induced in FVB/n mice or Wistar rats by caerulein, ethanol-palmitoleic acid, or L-ornithine-HCl. DMTS treatments were administered subcutaneously. AP severity was assessed by pancreatic histological scoring, pancreatic water content, and myeloperoxidase activity measurements. The behaviour of animals was followed. Pancreatic heat shock protein 72 (HSP72) expression, sulfide, and protein persulfidation were measured. In vitro acinar viability, intracellular Ca2+ concentration, and reactive oxygen species production were determined. DMTS dose-dependently decreased the severity of AP. It declined the pancreatic infiltration of leukocytes and cellular damage in mice. DMTS upregulated the HSP72 expression during AP and elevated serum sulfide and low molecular weight persulfide levels. DMTS exhibited cytoprotection against hydrogen peroxide and AP-inducing agents. It has antioxidant properties and modulates physiological but not pathophysiological Ca2+ signalling. Generally, DMTS ameliorated AP severity and protected pancreatic acinar cells. Our findings indicate that DMTS is a sulfur donor with anti-inflammatory and antioxidant effects, and organosulfur compounds require further investigation into this potentially lethal disease.

Suprapapillary Biliary Stents Have Longer Patency Times than Transpapillary Stents-A Systematic Review and Meta-Analysis.

BACKGROUND AND STUDY AIMS: Endoscopic biliary stent placement is a minimally invasive intervention for patients with biliary strictures. Stent patency and function time are crucial factors. Suprapapillary versus transpapillary stent positioning may contribute to stent function time, so a meta-analysis was performed in this comparison. METHODS: A comprehensive literature search was conducted in the CENTRAL, Embase, and MEDLINE databases to find data on suprapapillary stent placement compared to the transpapillary method via endoscopic retrograde cholangiopancreatography in cases of biliary stenosis of any etiology and any stent type until December 2020. We carried out a meta-analysis focusing on the following outcomes: stent patency, stent migration, rate of cholangitis and pancreatitis, and other reported complications. RESULTS: Three prospective and ten retrospective studies involving 1028 patients were included. Suprapapillary stent placement appeared to be superior to transpapillary stent positioning in patency (weighted mean difference = 50.23 days, 95% CI: 8.56, 91.98; p = 0.0.018). In a subgroup analysis of malignant indications, suprapapillary positioning showed a lower rate of cholangitis (OR: 0.34, 95% CI: 0.13, 0.93; p = 0.036). Another subgroup analysis investigating metal stents in a suprapapillary position resulted in a lower rate of pancreatitis (OR: 0.16, 95% CI: 0.03, 0.95; p = 0.043) compared to transpapillary stent placement. There was no difference in stent migration rates between the two groups (OR: 0.67, 95% CI: 0.17, 2.72; p = 0.577). CONCLUSIONS: Based on our results, suprapapillary biliary stenting has longer stent patency. Moreover, the stent migration rate did not differ between the suprapapillary and transpapillary groups.

Mechanisms linking hypertriglyceridemia to acute pancreatitis.

Hypertriglyceridemia (HTG) is a metabolic disorder, defined when serum or plasma triglyceride concentration (seTG) is >1.7 mM. HTG can be categorized as mild to very severe groups based on the seTG value. The risk of acute pancreatitis (AP), a serious disease with high mortality and without specific therapy, increases with the degree of HTG. Furthermore, even mild or moderate HTG aggravates AP initiated by other important etiological factors, including alcohol or bile stone. This review briefly summarizes the pathophysiology of HTG, the epidemiology of HTG-induced AP and the clinically observed effects of HTG on the outcomes of AP. Our main focus is to discuss the pathophysiological mechanisms linking HTG to AP. HTG is accompanied by an increased serum fatty acid (FA) concentration, and experimental results have demonstrated that these FAs have the most prominent role in causing the consequences of HTG during AP. FAs inhibit mitochondrial complexes in pancreatic acinar cells, induce pathological elevation of intracellular Ca2+ concentration, cytokine release and tissue injury, and reduce the function of pancreatic ducts. Furthermore, high FA concentrations can induce respiratory, kidney, and cardiovascular failure in AP. All these effects may contribute to the observed increased AP severity and frequent organ failure in patients. Importantly, experimental results suggest that the reduction of FA production by lipase inhibitors can open up new therapeutic options of AP. Overall, investigating the pathophysiology of HTG-induced AP or AP in the presence of HTG and determining possible treatments are needed.

Impaired regulation of PMCA activity by defective CFTR expression promotes epithelial cell damage in alcoholic pancreatitis and hepatitis.

Alcoholic pancreatitis and hepatitis are frequent, potentially lethal diseases with limited treatment options. Our previous study reported that the expression of CFTR Cl- channel is impaired by ethanol in pancreatic ductal cells leading to more severe alcohol-induced pancreatitis. In addition to determining epithelial ion secretion, CFTR has multiple interactions with other proteins, which may influence intracellular Ca2+ signaling. Thus, we aimed to investigate the impact of ethanol-mediated CFTR damage on intracellular Ca2+ homeostasis in pancreatic ductal epithelial cells and cholangiocytes. Human and mouse pancreas and liver samples and organoids were used to study ion secretion, intracellular signaling, protein expression and interaction. The effect of PMCA4 inhibition was analyzed in a mouse model of alcohol-induced pancreatitis. The decreased CFTR expression impaired PMCA function and resulted in sustained intracellular Ca2+ elevation in ethanol-treated and mouse and human pancreatic organoids. Liver samples derived from alcoholic hepatitis patients and ethanol-treated mouse liver organoids showed decreased CFTR expression and function, and impaired PMCA4 activity. PMCA4 co-localizes and physically interacts with CFTR on the apical membrane of polarized epithelial cells, where CFTR-dependent calmodulin recruitment determines PMCA4 activity. The sustained intracellular Ca2+ elevation in the absence of CFTR inhibited mitochondrial function and was accompanied with increased apoptosis in pancreatic epithelial cells and PMCA4 inhibition increased the severity of alcohol-induced AP in mice. Our results suggest that improving Ca2+ extrusion in epithelial cells may be a potential novel therapeutic approach to protect the exocrine pancreatic function in alcoholic pancreatitis and prevent the development of cholestasis in alcoholic hepatitis.

Noninvasive ventilation improves the outcome in patients with pneumonia-associated respiratory failure: Systematic review and meta-analysis.

BACKGROUND: Noninvasive ventilation (NIV) is beneficial in exacerbations of chronic obstructive pulmonary disease (COPD), but its effectiveness in pneumonia-associated respiratory failure is still controversial. In the current meta-analysis, we aimed to investigate whether the use of NIV before intubation in pneumonia improves the mortality and intubation rates of respiratory failure as compared to no use of NIV in adults. METHODS: We searched three databases from inception to December 2019. We included studies, in which pneumonia patients were randomized initially into either NIV-treated or non-NIV-treated groups. Five full-text publications, including 121 patients, reported eligible data for statistical analysis. RESULTS: With NIV the overall hospital mortality rate seemed lower in patients with pneumonia-associated respiratory failure, but this was not significant [odds ratio (OR) = 0.39; 95% confidence interval (CI): 0.13-1.14; P = 0.085]. In the intensive care unit, the mortality was significantly lower when NIV was applied compared to no NIV treatment (OR = 0.22; 95% CI: 0.07-0.75; P = 0.015). NIV also decreased mortality compared to no NIV in patient groups, which did not exclude patients with COPD (OR = 0.25; 95% CI: 0.08-0.74; P = 0.013). The need for intubation was significantly reduced in NIV-treated patients (OR = 0.22; 95% CI: 0.09-0.53; P = 0.001), which effect was more prominent in pneumonia patient groups not excluding patients with pre-existing COPD (OR = 0.13; 95% CI: 0.03-0.46; P = 0.002). CONCLUSION: NIV markedly decreases the death rate in the intensive care unit and reduces the need for intubation in patients with pneumonia-associated respiratory failure. The beneficial effects of NIV seem more pronounced in populations that include patients with COPD. Our findings suggest that NIV should be considered in the therapeutic guidelines of pneumonia, given that future clinical trials confirm the results of our meta-analysis. AVAILABILITY OF DATA AND MATERIALS: All data and materials generated during the current study are available from the corresponding author on reasonable request.

Blood-brain barrier dysfunction in L-ornithine induced acute pancreatitis in rats and the direct effect of L-ornithine on cultured brain endothelial cells.

BACKGROUND: In severe acute pancreatitis (AP) the CNS is affected manifesting in neurological symptoms. Earlier research from our laboratory showed blood-brain barrier (BBB) permeability elevation in a taurocholate-induced AP model. Here we aimed to further explore BBB changes in AP using a different, non-invasive in vivo model induced by L-ornithine. Our goal was also to identify whether L-ornithine, a cationic amino acid, has a direct effect on brain endothelial cells in vitro contributing to the observed BBB changes. METHODS: AP was induced in rats by the intraperitoneal administration of L-ornithine-HCl. Vessel permeability and the gene expression of the primary transporter of L-ornithine, cationic amino acid transporter-1 (Cat-1) in the brain cortex, pancreas, liver and lung were determined. Ultrastructural changes were followed by transmission electron microscopy. The direct effect of L-ornithine was tested on primary rat brain endothelial cells and a triple co-culture model of the BBB. Viability and barrier integrity, including permeability and TEER, nitrogen monoxide (NO) and reactive oxygen species (ROS) production and NF-κB translocation were measured. Fluorescent staining for claudin-5, occludin, ZO-1, ß-catenin, cell adhesion molecules Icam-1 and Vcam-1 and mitochondria was performed. Cell surface charge was measured by laser Doppler velocimetry. RESULTS: In the L-ornithine-induced AP model vessel permeability for fluorescein and Cat-1 expression levels were elevated in the brain cortex and pancreas. On the ultrastructural level surface glycocalyx and mitochondrial damage, tight junction and basal membrane alterations, and glial edema were observed. L-ornithine decreased cell impedance and elevated the BBB model permeability in vitro. Discontinuity in the surface glycocalyx labeling and immunostaining of junctional proteins, cytoplasmic redistribution of ZO-1 and ß-catenin, and elevation of Vcam-1 expression were measured. ROS production was increased and mitochondrial network was damaged without NF-κB, NO production or mitochondrial membrane potential alterations. Similar ultrastructural changes were seen in L-ornithine treated brain endothelial cells as in vivo. The basal negative zeta potential of brain endothelial cells became more positive after L-ornithine treatment. CONCLUSION: We demonstrated BBB damage in the L-ornithine-induced rat AP model suggesting a general, AP model independent effect. L-ornithine induced oxidative stress, decreased barrier integrity and altered BBB morphology in a culture BBB model. These data suggest a direct effect of the cationic L-ornithine on brain endothelium. Endothelial surface glycocalyx injury was revealed both in vivo and in vitro, as an additional novel component of the BBB-related pathological changes in AP.

Fentanyl but Not Morphine or Buprenorphine Improves the Severity of Necrotizing Acute Pancreatitis in Rats.

Opioids are widely used for the pain management of acute pancreatitis (AP), but their impact on disease progression is unclear. Therefore, our aim was to study the effects of clinically relevant opioids on the severity of experimental AP. Various doses of fentanyl, morphine, or buprenorphine were administered as pre- and/or post-treatments in rats. Necrotizing AP was induced by the intraperitoneal injection of L-ornithine-HCl or intra-ductal injection of Na-taurocholate, while intraperitoneal caerulein administration caused edematous AP. Disease severity was determined by laboratory and histological measurements. Mu opioid receptor (MOR) expression and function was assessed in control and AP animals. MOR was expressed in both the pancreas and brain. The pancreatic expression and function of MOR were reduced in AP. Fentanyl post-treatment reduced necrotizing AP severity, whereas pre-treatment exacerbated it. Fentanyl did not affect the outcome of edematous AP. Morphine decreased vacuolization in edematous AP, while buprenorphine pre-treatment increased pancreatic edema during AP. The overall effects of morphine on disease severity were negligible. In conclusion, the type, dosing, administration route, and timing of opioid treatment can influence the effects of opioids on AP severity. Fentanyl post-treatment proved to be beneficial in AP. Clinical studies are needed to determine which opioids are best in AP.

Kynurenic Acid and Its Analogue SZR-72 Ameliorate the Severity of Experimental Acute Necrotizing Pancreatitis.

The pathophysiology of acute pancreatitis (AP) is not well understood, and the disease does not have specific therapy. Tryptophan metabolite L-kynurenic acid (KYNA) and its synthetic analogue SZR-72 are antagonists of the N-methyl-D-aspartate receptor (NMDAR) and have immune modulatory roles in several inflammatory diseases. Our aims were to investigate the effects of KYNA and SZR-72 on experimental AP and to reveal their possible mode of action. AP was induced by intraperitoneal (i.p.) injection of L-ornithine-HCl (LO) in SPRD rats. Animals were pretreated with 75-300 mg/kg KYNA or SZR-72. Control animals were injected with physiological saline instead of LO, KYNA and/or SZR-72. Laboratory and histological parameters, as well as pancreatic and systemic circulation were measured to evaluate AP severity. Pancreatic heat shock protein-72 and IL-1ß were measured by western blot and ELISA, respectively. Pancreatic expression of NMDAR1 was investigated by RT-PCR and immunohistochemistry. Viability of isolated pancreatic acinar cells in response to LO, KYNA, SZR-72 and/or NMDA administration was assessed by propidium-iodide assay. The effects of LO and/or SZR-72 on neutrophil granulocyte function was also studied. Almost all investigated laboratory and histological parameters of AP were significantly reduced by administration of 300 mg/kg KYNA or SZR-72, whereas the 150 mg/kg or 75 mg/kg doses were less or not effective, respectively. The decreased pancreatic microcirculation was also improved in the AP groups treated with 300 mg/kg KYNA or SZR-72. Interestingly, pancreatic heat shock protein-72 expression was significantly increased by administration of SZR-72, KYNA and/or LO. mRNA and protein expression of NMDAR1 was detected in pancreatic tissue. LO treatment caused acinar cell toxicity which was reversed by 250 µM KYNA or SZR-72. Treatment of acini with NMDA (25, 250, 2000 µM) did not influence the effects of KYNA or SZR-72. Moreover, SZR-72 reduced LO-induced H2O2 production of neutrophil granulocytes. KYNA and SZR-72 have dose-dependent protective effects on LO-induced AP or acinar toxicity which seem to be independent of pancreatic NMDA receptors. Furthermore, SZR-72 treatment suppressed AP-induced activation of neutrophil granulocytes. This study suggests that administration of KYNA and its derivative could be beneficial in AP.

Mislocalization of CFTR expression in acute pancreatitis and the beneficial effect of VX-661 + VX-770 treatment on disease severity.

Cystic fibrosis transmembrane conductance regulator (CFTR) has an essential role in maintaining pancreatic ductal function. Impaired CFTR function can trigger acute pancreatitis (AP) and exacerbate disease severity. We aimed to investigate the localization and expression of CFTR during AP, and determined the effects of a CFTR corrector (VX-661) and potentiator (VX-770) on disease severity. AP was induced in FVB/n mice by 6-10 hourly intraperitoneal injections of 50 µg/kg cerulein. Some mice were pre-treated with five to six daily injections of 2 mg/kg VX-661 + VX-770. Control animals were administered physiological saline instead of cerulein and dimethyl sulfoxide instead of VX compounds. AP severity was determined by measuring laboratory and histological parameters; CFTR and CK19 expression was measured. Activity of ion transporters was followed by intracellular pH or fluid secretion measurement of isolated pancreatic intra-/interlobular ducts. Cerulein-induced AP severity was greatest between 12 and 24 h. CFTR mRNA expression was significantly increased 24 h after AP induction. Immunohistochemistry demonstrated disturbed staining morphology of CFTR and CK19 proteins in AP. Mislocalization of CFTR protein was observed from 6 h, while expression increased at 24 h compared to control. Ductal HCO3- transport activity was significantly increased 6 h after AP induction. AP mice pre-treatment with VX-661 + VX-770 significantly reduced the extent of tissue damage by about 20-30%, but other parameters were unchanged. Interestingly, VX-661 + VX-770 in vitro administration significantly increased the fluid secretion of ducts derived from AP animals. This study described the course of the CFTR expression and mislocalization in cerulein-induced AP. Our results suggest that the beneficial effects of CFTR correctors and potentiators should be further investigated in AP. KEY POINTS: Cystic fibrosis transmembrane conductance regulator (CFTR) is an important ion channel in epithelial cells. Its malfunction has several serious consequences, like developing or aggravating acute pancreatitis (AP). Here, the localization and expression of CFTR during cerulein-induced AP in mice were investigated and the effects of CFTR corrector (VX-661) and a potentiator (VX-770) on disease severity were determined. CFTR mRNA expression was significantly increased and mislocalization of CFTR protein was observed in AP compared to the control group. Interestingly, pre-treatment of AP mice with VX-661 + VX-770 significantly reduced the extent of pancreatic tissue damage by 20-30%. In vitro administration of VX-661 + VX-770 significantly increased the fluid secretion of ducts derived from AP animals. Based on these results, the utilization of CFTR correctors and potentiators should be further investigated in AP.

Dysregulation of mannose-6-phosphate-dependent cholesterol homeostasis in acinar cells mediates pancreatitis.

Disordered lysosomal/autophagy pathways initiate and drive pancreatitis, but the underlying mechanisms and links to disease pathology are poorly understood. Here, we show that the mannose-6-phosphate (M6P) pathway of hydrolase delivery to lysosomes critically regulates pancreatic acinar cell cholesterol metabolism. Ablation of the Gnptab gene encoding a key enzyme in the M6P pathway disrupted acinar cell cholesterol turnover, causing accumulation of nonesterified cholesterol in lysosomes/autolysosomes, its depletion in the plasma membrane, and upregulation of cholesterol synthesis and uptake. We found similar dysregulation of acinar cell cholesterol, and a decrease in GNPTAB levels, in both WT experimental pancreatitis and human disease. The mechanisms mediating pancreatic cholesterol dyshomeostasis in Gnptab-/- and experimental models involve a disordered endolysosomal system, resulting in impaired cholesterol transport through lysosomes and blockage of autophagic flux. By contrast, in Gnptab-/- liver the endolysosomal system and cholesterol homeostasis were largely unaffected. Gnptab-/- mice developed spontaneous pancreatitis. Normalization of cholesterol metabolism by pharmacologic means alleviated responses of experimental pancreatitis, particularly trypsinogen activation, the disease hallmark. The results reveal the essential role of the M6P pathway in maintaining exocrine pancreas homeostasis and function, and implicate cholesterol disordering in the pathogenesis of pancreatitis.

Pancreatitis severity in mice with impaired CFTR function but pancreatic sufficiency is mediated via ductal and inflammatory cells-Not acinar cells.

Mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) are an established risk factor for cystic fibrosis (CF) and chronic pancreatitis. Whereas patients with CF usually develop complete exocrine pancreatic insufficiency, pancreatitis patients with CFTR mutations have mostly preserved exocrine pancreatic function. We therefore used a strain of transgenic mice with significant residual CFTR function (CFTRtm1HGU ) to induce pancreatitis experimentally by serial caerulein injections. Protease activation and necrosis were investigated in isolated acini, disease severity over 24h, pancreatic function by MRI, isolated duct stimulation and faecal chymotrypsin, and leucocyte function by ex vivo lipopolysaccharide (LPS) stimulation. Pancreatic and lung injury were more severe in CFTRtm1HGU but intrapancreatic trypsin and serum enzyme activities higher than in wild-type controls only at 8h, a time interval previously attributed to leucocyte infiltration. CCK-induced trypsin activation and necrosis in acini from CFTRtm1HGU did not differ from controls. Fluid and bicarbonate secretion were greatly impaired, whereas faecal chymotrypsin remained unchanged. LPS stimulation of splenocytes from CFTRtm1HGU resulted in increased INF-γ and IL-6, but decreased IL-10 secretion. CFTR mutations that preserve residual pancreatic function significantly increase the severity of experimental pancreatitis-mostly via impairing duct cell function and a shift towards a pro-inflammatory phenotype, not by rendering acinar cells more susceptible to pathological stimuli.

Pre-existing Liver Diseases and On-Admission Liver-Related Laboratory Tests in COVID-19: A Prognostic Accuracy Meta-Analysis With Systematic Review.

Background: We aimed to perform a systematic search and meta-analysis to evaluate the prognostic value of on-admission liver function tests and pre-existing liver diseases on the clinical course of coronavirus disease 2019 (COVID-19). Methods: The study was registered on PROSPERO (CRD42020182902). We searched five databases between 01/01/2020 and 04/23/2020. Studies that reported on liver-related comorbidities and/or laboratory parameters in patients with COVID-19 were included. The main outcomes were COVID-19 severity, intensive care unit (ICU) admission, and in-hospital mortality. Analysis of predictive models hierarchical summary receiver-operating characteristic (HSROC) was conducted with a 95% confidence interval (CI). Results: Fifty studies were included in the meta-analysis. High specificity was reached by acute liver failure associated by COVID-19 (0.94, 95% CI: 0.71-0.99) and platelet count (0.94, 95% CI: 0.71-0.99) in the case of mortality; chronic liver disease (CLD) (0.98, 95% CI: 0.96-0.99) and platelet count (0.82, 95% CI: 0.72-0.89) in the case of ICU requirement; and CLD (0.97, 95% CI: 0.95-0.98), chronic hepatitis B infection (0.97, 95% CI: 0.95-0.98), platelet count (0.86, 95% CI: 0.77-0.91), and alanine aminotransferase (ALT) (0.80, 95% CI: 0.66-0.89) and aspartate aminotransferase (AST) (0.84, 95% CI: 0.77-0.88) activities considering severe COVID-19. High sensitivity was found in the case of C-reactive protein (CRP) for ICU requirement (0.92, 95% CI: 0.80-0.97) and severe COVID-19 (0.91, 95% CI: 0.82-0.96). Conclusion: On-admission platelet count, ALT and AST activities, CRP concentration, and the presence of acute and CLDs predicted the severe course of COVID-19. To highlight, pre-existing liver diseases or acute liver injury associated by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection plays an important role in the prediction of mortality.

Assessment of the course of acute pancreatitis in the light of aetiology: a systematic review and meta-analysis.

The main causes of acute pancreatitis (AP) are biliary disease, alcohol consumption, hypertriglyceridaemia (HTG) and endoscopic retrograde cholangiopancreatography (ERCP). The aim of this meta-analysis was to evaluate the effects of these aetiological factors on the severity and outcome of AP. Pubmed and Embase were searched between 01/01/2012 and 31/05/2020. Included articles involved adult alcoholic, biliary, HTG- or post-ERCP AP (PAP) patients. Primary outcome was severity, secondary outcomes were organ failures, intensive care unit admission, recurrence rate, pancreatic necrosis, mortality, length of hospital stay, pseudocyst, fluid collection and systematic inflammatory response syndrome. Data were analysed from 127 eligible studies. The risk for non-mild (moderately severe and severe) condition was the highest in HTG-induced AP (HTG-AP) followed by alcoholic AP (AAP), biliary AP (BAP) and PAP. Recurrence rate was significantly lower among BAP vs. HTG-AP or AAP patients (OR = 2.69 and 2.98, 95% CI 1.55-4.65 and 2.22-4.01, respectively). Mortality rate was significantly greater in HTG-AP vs. AAP or BAP (OR = 1.72 and 1.50, 95% CI 1.04-2.84 and 0.96-2.35, respectively), pancreatic necrosis occurred more frequently in AAP than BAP patients (OR = 1.58, 95% CI 1.08-2.30). Overall, there is a potential association between aetiology and the development and course of AP. HTG-AP is associated with the highest number of complications. Furthermore, AAP is likely to be more severe than BAP or PAP. Greater emphasis should be placed on determining aetiology on admission.

The Effect of Sodium Bicarbonate, a Beneficial Adjuvant Molecule in Cystic Fibrosis, on Bronchial Epithelial Cells Expressing a Wild-Type or Mutant CFTR Channel.

Clinical and experimental results with inhaled sodium bicarbonate as an adjuvant therapy in cystic fibrosis (CF) are promising due to its mucolytic and bacteriostatic properties, but its direct effect has not been studied on respiratory epithelial cells. Our aim was to establish and characterize co-culture models of human CF bronchial epithelial (CFBE) cell lines expressing a wild-type (WT) or mutant (deltaF508) CF transmembrane conductance regulator (CFTR) channel with human vascular endothelial cells and investigate the effects of bicarbonate. Vascular endothelial cells induced better barrier properties in CFBE cells as reflected by the higher resistance and lower permeability values. Activation of CFTR by cAMP decreased the electrical resistance in WT but not in mutant CFBE cell layers confirming the presence and absence of functional channels, respectively. Sodium bicarbonate (100 mM) was well-tolerated by CFBE cells: it slightly reduced the impedance of WT but not that of the mutant CFBE cells. Sodium bicarbonate significantly decreased the more-alkaline intracellular pH of the mutant CFBE cells, while the barrier properties of the models were only minimally changed. These observations indicate that sodium bicarbonate is beneficial to deltaF508-CFTR expressing CFBE cells. Thus, sodium bicarbonate may have a direct therapeutic effect on the bronchial epithelium.

Double Stenting for Malignant Biliary and Duodenal Obstruction: A Systematic Review and Meta-Analysis.

INTRODUCTION: Data about the efficacy of palliative double stenting for malignant duodenal and biliary obstruction are limited. METHODS: A systematic literature search was performed to assess the feasibility and optimal method of double stenting for malignant duodenobiliary obstruction compared with surgical double bypass in terms of technical and clinical success, adverse events, reinterventions, and survival. Event rates with 95% confidence intervals were calculated. RESULTS: Seventy-two retrospective and 8 prospective studies published until July 2018 were included. Technical and clinical success rates of double stenting were 97% (95%-99%) and 92% (89%-95%), respectively. Clinical success of endoscopic biliary stenting was higher than that of surgery (97% [94%-99%] vs 86% [78%-92%]). Double stenting was associated with less adverse events (13% [8%-19%] vs 28% [19%-38%]) but more frequent need for reintervention (21% [16%-27%] vs 10% [4%-19%]) than double bypass. No significant difference was found between technical and clinical success and reintervention rate of endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic drainage, and endoscopic ultrasound-guided biliary drainage. ERCP was associated with the least adverse events (3% [1%-6%]), followed by percutaneous transhepatic drainage (10% [0%-37%]) and endoscopic ultrasound-guided biliary drainage (23% [15%-33%]). DISCUSSION: Substantially high technical and clinical success can be achieved with double stenting. Based on the adverse event profile, ERCP can be recommended as the first choice for biliary stenting as part of double stenting, if feasible. Prospective comparative studies with well-defined outcomes and cohorts are needed.

International Consensus Guidelines for Risk Factors in Chronic Pancreatitis. Recommendations from the working group for the international consensus guidelines for chronic pancreatitis in collaboration with the International Association of Pancreatology, the American Pancreatic Association, the Japan Pancreas Society, and European Pancreatic Club.

BACKGROUND: Chronic pancreatitis (CP) is a complex inflammatory disease with remarkably impaired quality of life and permanent damage of the pancreas. This paper is part of the international consensus guidelines on CP and presents the consensus on factors elevating the risk for CP. METHODS: An international working group with 20 experts on CP from the major pancreas societies (IAP, APA, JPS, and EPC) evaluated 14 statements generated from evidence on four questions deemed to be the most clinically relevant in CP. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to evaluate the level of evidence available per statement. To determine the level of agreement, the working group voted on the 14 statements for strength of agreement, using a nine-point Likert scale in order to calculate Cronbach's alpha reliability coefficient. RESULTS: Strong consensus and agreement were obtained for the following statements: Alcohol, smoking, and certain genetic alterations are risk factors for CP. Past history, family history, onset of symptoms, and life-style factors including alcohol intake and smoking history should be determined. Alcohol consumption dose-dependently elevates the risk of CP up to 4-fold. Ever smokers, even smoking less than a pack of cigarettes per day, have an increased risk for CP, as compared to never smokers. CONCLUSIONS: Both genetic and environmental factors can markedly elevate the risk for CP. Therefore, health-promoting lifestyle education and in certain cases genetic counselling should be employed to reduce the incidence of CP.

TRPM2-mediated extracellular Ca2+ entry promotes acinar cell necrosis in biliary acute pancreatitis.

KEY POINTS: Acute biliary pancreatitis is a significant clinical challenge as currently no specific pharmaceutical treatment exists. Intracellular Ca2+ overload, increased reactive oxygen species (ROS) production, mitochondrial damage and intra-acinar digestive enzyme activation caused by bile acids are hallmarks of acute biliary pancreatitis. Transient receptor potential melastatin 2 (TRPM2) is a non-selective cation channel that has recently emerged as an important contributor to oxidative-stress-induced cellular Ca2+ overload across different diseases. We demonstrated that TRPM2 is expressed in the plasma membrane of mouse pancreatic acinar and ductal cells, which can be activated by increased oxidative stress induced by H2 O2 treatment and contributed to bile acid-induced extracellular Ca2+ influx in acinar cells, which promoted acinar cell necrosis in vitro and in vivo. These results suggest that the inhibition of TRPM2 may be a potential treatment option for biliary pancreatitis. ABSTRACT: Acute biliary pancreatitis poses a significant clinical challenge as currently no specific pharmaceutical treatment exists. Disturbed intracellular Ca2+ signalling caused by bile acids is a hallmark of the disease, which induces increased reactive oxygen species (ROS) production, mitochondrial damage, intra-acinar digestive enzyme activation and cell death. Because of this mechanism of action, prevention of toxic cellular Ca2+ overload is a promising therapeutic target. Transient receptor potential melastatin 2 (TRPM2) is a non-selective cation channel that has recently emerged as an important contributor to oxidative-stress-induced cellular Ca2+ overload across different diseases. However, the expression and possible functions of TRPM2 in the exocrine pancreas remain unknown. Here we found that TRPM2 is expressed in the plasma membrane of mouse pancreatic acinar and ductal cells, which can be activated by increased oxidative stress induced by H2 O2 treatment. TRPM2 activity was found to contribute to bile acid-induced extracellular Ca2+ influx in acinar cells, but did not have the same effect in ductal cells. The generation of intracellular ROS in response to bile acids was remarkably higher in pancreatic acinar cells compared to isolated ducts, which can explain the difference between acinar and ductal cells. This activity promoted acinar cell necrosis in vitro independently from mitochondrial damage or mitochondrial fragmentation. In addition, bile-acid-induced experimental pancreatitis was less severe in TRPM2 knockout mice, whereas the lack of TRPM2 had no protective effect in cerulein-induced acute pancreatitis. Our results suggest that the inhibition of TRPM2 may be a potential treatment option for biliary pancreatitis.

Mouse pancreatic ductal organoid culture as a relevant model to study exocrine pancreatic ion secretion.

Pancreatic exocrine secretory processes are challenging to investigate on primary epithelial cells. Pancreatic organoid cultures may help to overcome shortcomings of the current models, however the ion secretory processes in pancreatic organoids-and therefore their physiological relevance or their utility in disease modeling-are not known. To answer these questions, we provide side-by-side comparison of gene expression, morphology, and function of epithelial cells in primary isolated pancreatic ducts and organoids. We used mouse pancreatic ductal fragments for experiments or were grown in Matrigel to obtain organoid cultures. Using PCR analysis we showed that gene expression of ion channels and transporters remarkably overlap in primary ductal cells and organoids. Morphological analysis with scanning electron microscopy revealed that pancreatic organoids form polarized monolayers with brush border on the apical membrane. Whereas the expression and localization of key proteins involved in ductal secretion (cystic fibrosis transmembrane conductance regulator, Na+/H+ exchanger 1 and electrogenic Na+/HCO3- cotransporter 1) are equivalent to the primary ductal fragments. Measurements of intracellular pH and Cl- levels revealed no significant difference in the activities of the apical Cl-/HCO3- exchange, or in the basolateral Na+ dependent HCO3- uptake. In summary we found that ion transport activities in the mouse pancreatic organoids are remarkably similar to those observed in freshly isolated primary ductal fragments. These results suggest that organoids can be suitable and robust model to study pancreatic ductal epithelial ion transport in health and diseases and facilitate drug development for secretory pancreatic disorders like cystic fibrosis, or chronic pancreatitis.

Novel mitochondrial transition pore inhibitor N-methyl-4-isoleucine cyclosporin is a new therapeutic option in acute pancreatitis.

KEY POINTS: •Bile acids, ethanol and fatty acids affect pancreatic ductal fluid and bicarbonate secretion via mitochondrial damage, ATP depletion and calcium overload. •Pancreatitis-inducing factors open the membrane transition pore (mPTP) channel via cyclophilin D activation in acinar cells, causing calcium overload and cell death; genetic or pharmacological inhibition of mPTP improves the outcome of acute pancreatitis in animal models. •Here we show that genetic and pharmacological inhibition of mPTP protects mitochondrial homeostasis and cell function evoked by pancreatitis-inducing factors in pancreatic ductal cells. •The results also show that the novel cyclosporin A derivative NIM811 protects mitochondrial function in acinar and ductal cells, and it preserves bicarbonate transport mechanisms in pancreatic ductal cells. •We found that NIM811 is highly effective in different experimental pancreatitis models and has no side-effects. NIM811 is a highly suitable compound to be tested in clinical trials. ABSTRACT: Mitochondrial dysfunction plays a crucial role in the development of acute pancreatitis (AP); however, no compound is currently available with clinically acceptable effectiveness and safety. In this study, we investigated the effects of a novel mitochondrial transition pore inhibitor, N-methyl-4-isoleucine cyclosporin (NIM811), in AP. Pancreatic ductal and acinar cells were isolated by enzymatic digestion from Bl/6 mice. In vitro measurements were performed by confocal microscopy and microfluorometry. Preventative effects of pharmacological [cylosporin A (2 µm), NIM811 (2 µm)] or genetic (Ppif-/- /Cyp D KO) inhibition of the mitochondrial transition pore (mPTP) during the administration of either bile acids (BA) or ethanol + fatty acids (EtOH+FA) were examined. Toxicity of mPTP inhibition was investigated by detecting apoptosis and necrosis. In vivo effects of the most promising compound, NIM811 (5 or 10 mg kg-1 per os), were checked in three different AP models induced by either caerulein (10 × 50 µg kg-1 ), EtOH+FA (1.75 g kg-1 ethanol and 750 mg kg-1 palmitic acid) or 4% taurocholic acid (2 ml kg-1 ). Both genetic and pharmacological inhibition of Cyp D significantly prevented the toxic effects of BA and EtOH+FA by restoring mitochondrial membrane potential (Δψ) and preventing the loss of mitochondrial mass. In vivo experiments revealed that per os administration of NIM811 has a protective effect in AP by reducing oedema, necrosis, leukocyte infiltration and serum amylase level in AP models. Administration of NIM811 had no toxic effects. The novel mitochondrial transition pore inhibitor NIM811 thus seems to be an exceptionally good candidate compound for clinical trials in AP.