Pancreatic Bicarbonate Secretion Research Articles

B-067 Performance Assessment of a Newly Developed Lateral Flow Assay for the Quantification of Faecal Pancreatic Elastase

Abstract Background Pancreatic exocrine insufficiency (PEI) can be defined as an insufficient secretion of pancreatic enzymes and bicarbonate to maintain a normal digestion (1). PEI is associated to fat malabsorption, weight loss and malnutrition-related complications. Due to its important role in the digestive process, as a proteolytic enzyme and the high stability of the enzyme during intestinal transit, fecal pancreatic elastase (fPELA) is an ideal biomarker for the assessment of pancreatic function in patients suffering from PEI. The aim of this work was to develop and optimize a new rapid test for the quantification of fPELA. Methods A quantitative lateral flow assay was designed for the selective measurement of elastase antigen concentrations from stool extracts. The BÜHLMANN Quantum Blue® fPELA is a sandwich immunoassay. A monoclonal detection antibody is conjugated to gold nanoparticles. Elastase present in the sample binds to this gold conjugate. A polyclonal capture antibody, highly specific for elastase, is immobilized on the analytical membrane and captures the complex of elastase bound to the anti-elastase gold conjugate, resulting in a coloring of the test line. The remaining free anti-elastase gold conjugate binds to the control line. The signal intensities of the test line and the control line are measured quantitatively by the Quantum Blue® Reader. Pancreatic elastase is quantified in extracts of human stool samples collected with the BÜHLMANN CALEX® Cap device. Several analytical studies, such as sensitivity, linearity, High Dose Hook Effect (HDHE), were performed during optimization phase to assess the performance of the assay. Moreover, a method comparison with the commercially available high throughput turbidimetric BÜHLMANN fPELA® turbo assay was also performed. Results Both analytical and clinical performance were evaluated. Preliminary results of the assay performance were obtained during the optimization phase. Analytical sensitivity was determined as 12.8 µg/g LoB, 16.6 µg/g LoD and 17.2 µg/g LoQ. The linearity evaluation revealed a linear range of 10 to 472 µg/g. No HDHE was observed in native samples up to 4000 µg/g. Method comparison of the new lateral flow assay with BÜHLMANN fPELA® turbo assay, with 80 clinical samples, revealed good analytical agreement with a slope of 1.04 (Passing-Bablok) and a bias at cutoff (200 µg/g) of 5.6%. Relative bias (Bland-Altman) of the two assays was 6.9%. Considering the turbidimetric assay as the reference method, the sensitivity and specificity were 92% and 83%, respectively. Conclusion The newly developed quantitative lateral flow assay, BÜHLMANN Quantum Blue® fPELA, is an accurate, non-invasive and rapid test to determine fPELA levels in fecal extracts. The lateral flow assay is an attractive alternative to ELISA with a turn-around time of only 15 minutes enabling patients’ management in a more patient near clinical environment.

Pancreatic duct organoid swelling is chloride-dependent

Pancreatic secretions become viscous and acidic in Cystic fibrosis (CF), highlighting the role of CFTR in pancreatic fluid and bicarbonate secretion. Forskolin-induced swelling (FIS) assay developed in intestinal organoids measures residual CFTR function. It is not known whether FIS reflects bicarbonate secretion in pancreas, an organ that secretes near-isotonic NaHCO3 levels. To investigate this, we generated pancreatic duct organoids from CF and non-CF pigs. Epithelial and ductal origin was confirmed with epithelial markers, ion transporters and lack of acinar, islet cell markers. CF organoids were small with no identifiable lumen; CFTR was expressed only in non-CF organoids. Utilizing FIS, organoid size increased only in response to chloride, not bicarbonate. This report highlights pancreatic duct organoids isolated for the first time from CF pigs and evidence for chloride and not bicarbonate driving pancreatic organoid swelling. These organoids would be useful to test chloride permeability of CFTR mutations that cause CF pancreatic disease.

Pancreatic Elastography Predicts Endoscopic Secretin-Pancreatic Function Test Result in Patients With Early Changes of Chronic Pancreatitis: A Prospective, Cross-Sectional, Observational Study.

The endoscopic pancreatic function test (ePFT) has been proposed for the evaluation of patients with suspected early chronic pancreatitis (CP) in the appropriate clinical context, but the cost and duration of the test limit its clinical applicability. Pancreatic secretion decreases as pancreatic fibrosis develops in CP. Pancreatic fibrosis can be quantified by endoscopic ultrasound-elastography (EUS-E). We aim at evaluating whether EUS-E correlates with and could replace ePFT for the evaluation of patients with suspected CP. A prospective, cross-sectional, and observational study of patients with clinical suspicion of CP and inconclusive EUS findings was conducted. EUS-E and ePFT were performed. Diagnosis of CP was supported if the ePFT result (bicarbonate peak) was abnormally low (<80 mEq/L). Correlation between EUS-E (strain ratio [SR]) and ePFT results was analyzed by linear regression. Diagnostic accuracy of EUS-E for CP was calculated using ePFT as a reference method. Sixty-one patients were included and analyzed. The mean peak bicarbonate concentration at the ePFT was 63.8 ± 23.6 mEq/L, and it was abnormally low in 50 patients (82.0%). The mean SR was 3.85 ± 1.24. Correlation between SR and bicarbonate secretion was highly significant ( r = 0.715, P < 0.0001). Diagnostic accuracy of EUS-E for CP was 93.4%. The degree of pancreatic fibrosis as evaluated by EUS-E correlates significantly with the secretin-stimulated pancreatic secretion of bicarbonate in patients with clinical suspicion of CP and inconclusive EUS findings of the disease. EUS-E could replace ePFT for the evaluation of these patients in clinical practice.

Pancreatic ductal fluid and bicarbonate secretion of the new animal models;ferrets and pigs

Pancreatic ductal fluid and bicarbonate secretion of the new animal models;ferrets and pigs

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

•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. 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 (2µm), NIM811 (2µm)] 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 10mgkg-1 per os), were checked in three different AP models induced by either caerulein (10×50µgkg-1 ), EtOH+FA (1.75gkg-1 ethanol and 750mgkg-1 palmitic acid) or 4% taurocholic acid (2mlkg-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.

Pancreatic ductal fluid and bicarbonate secretion of the newborn ferret and pig models of cystic fibrosis (CF)

Pancreatic ductal fluid and bicarbonate secretion of the newborn ferret and pig models of cystic fibrosis (CF)

Azathioprine and mesalamine can impair pancreatic ductal bicarbonate secretion in mice

The pattern of ketamine-induced locomotor activity varies substantially across ontogeny and according to sex. Although ketamine is classified as an NMDA channel blocker, it appears to stimulate the locomotor activity of both male and female rats via a monoaminergic mechanism. To more precisely determine the neural mechanisms underlying ketamine’s actions, male and female preweanling and adolescent rats were pretreated with vehicle, the dopamine (DA) synthesis inhibitor ∝-methyl-DL-p-tyrosine (AMPT), or the serotonin (5-HT) synthesis inhibitor 4-chloro-DL-phenylalanine methyl ester hydrochloride (PCPA). After completion of the pretreatment regimen, the locomotor activating effects of saline, ketamine, d-amphetamine, and cocaine were assessed during a 2 h test session. In addition, the ability of AMPT and PCPA to reduce dorsal striatal DA and 5-HT content was measured in male and female preweanling, adolescent, and adult rats. Results showed that AMPT and PCPA reduced, but did not fully attenuate, the ketamine-induced locomotor activity of preweanling rats and female adolescent rats. Ketamine (20 and 40 mg/kg) caused a minimal amount of locomotor activity in male adolescent rats, and this effect was not significantly modified by AMPT or PCPA pretreatment. When compared to ketamine, d-amphetamine and cocaine produced different patterns of locomotor activity across ontogeny; moreover, AMPT and PCPA pretreatment affected psychostimulant- and ketamine-induced locomotion differently. When these results are considered together, it appears that both dopaminergic and serotonergic mechanisms mediate the ketamine-induced locomotor activity of preweanling and female adolescent rats. The dichotomous actions of ketamine relative to the psychostimulants in vehicle-, AMPT-, and PCPA-treated rats, suggests that ketamine modulates DA and 5-HT neurotransmission through an indirect mechanism.

Development of a polarized pancreatic ductular cell epithelium for physiological studies.

Pancreatic ductular epithelial cells comprise the majority of duct cells in pancreas, control cystic fibrosis transmembrane conductance regulator (CFTR)-dependent bicarbonate ([Formula: see text]) secretion, but are difficult to grow as a polarized monolayer. Using NIH-3T3-J2 fibroblast feeder cells and a Rho-associated kinase inhibitor, we produced well-differentiated and polarized porcine pancreatic ductular epithelial cells. Cells grown on semipermeable filters at the air-liquid interface developed typical epithelial cell morphology and stable transepithelial resistance and expressed epithelial cell markers (zona occludens-1 and β-catenin), duct cell markers (SOX-9 and CFTR), but no acinar (amylase) or islet cell (chromogranin) markers. Polarized cells were studied in Ussing chambers bathed in Krebs-Ringer [Formula: see text] solution at 37°C gassed with 5% CO2 to measure short-circuit currents ( Isc). Ratiometric measurement of extracellular pH was performed with fluorescent SNARF-conjugated dextran at 5% CO2. Cells demonstrated a baseline Isc (12.2 ± 3.2 μA/cm2) that increased significantly in response to apical forskolin-IBMX (∆ Isc: 35.4 ± 3.8 μA/cm2, P < 0.001) or basolateral secretin (∆ Isc: 31.4 ± 2.5 μA/cm2, P < 0.001), both of which increase cellular levels of cAMP. Subsequent addition of apical GlyH-101, a CFTR inhibitor, decreased the current (∆ Isc: 20.4 ± 3.8 μA/cm2, P < 0.01). Extracellular pH and [Formula: see text] concentration increased significantly after forskolin-IBMX (pH: 7.18 ± 0.23 vs. 7.53 ± 0.19; [Formula: see text] concentration, 14.5 ± 5.9 vs. 31.8 ± 13.4 mM; P < 0.05 for both). We demonstrate the development of a polarized pancreatic ductular epithelial cell epithelium with CFTR-dependent [Formula: see text] secretion in response to secretin and cAMP. This model is highly relevant, as porcine pancreas physiology is very similar to humans and pancreatic damage in the cystic fibrosis pig model recapitulates that of humans. NEW & NOTEWORTHY Pancreas ductular epithelial cells control cystic fibrosis transmembrane conductance regulator (CFTR)-dependent bicarbonate secretion. Their function is critical because when CFTR is deficient in cystic fibrosis bicarbonate secretion is lost and the pancreas is damaged. Mechanisms that control pancreatic bicarbonate secretion are incompletely understood. We generated well-differentiated and polarized porcine pancreatic ductular epithelial cells and demonstrated feasibility of bicarbonate secretion. This novel method will advance our understanding of pancreas physiology and mechanisms of bicarbonate secretion.

A new animal model for epithelial ion transport modeling (focusing on CFTR) - Characterization of pancreatic ductal fluid and bicarbonate secretion in wild type ferrets

A new animal model for epithelial ion transport modeling (focusing on CFTR) - Characterization of pancreatic ductal fluid and bicarbonate secretion in wild type ferrets

585 - Correlation between Pancreatic Secretion of Bicarbonate and the Degree of Pancreatic Fibrosis in Patients with Early Morphological Changes of Chronic Pancreatitis

585 - Correlation between Pancreatic Secretion of Bicarbonate and the Degree of Pancreatic Fibrosis in Patients with Early Morphological Changes of Chronic Pancreatitis

Últimos avances en pancreatitis crónica

This article summarizes some of the recent and clinically relevant advances in chronic pancreatitis. These advances mainly concern the definition of the disease, the etiological diagnosis of idiopathic disease, the correlation between fibrosis degree and pancreatic secretion in the early stages of chronic pancreatitis, the treatment of the disease and of pain, the clinical relevance of pancreatic exocrine insufficiency, and the diagnosis of autoimmune pancreatitis. A new mechanistic definition of chronic pancreatitis has been proposed. Genetic testing is mainly of help in patients with relapsing idiopathic pancreatitis. A significant correlation has been shown between the degree of pancreatic fibrosis as evaluated by elastography and pancreatic secretion of bicarbonate. New data supports the efficacy of antioxidants and simvastatin for the therapy of chronic pancreatitis. The pancreatoscopy-guided intraductal lithotripsy is an effective alternative to extracorporeal shock wave lithotripsy in patients with chronic calcifying pancreatitis. The presence of pancreatic exocrine insufficiency in patients with chronic pancreatitis is associated with a significant risk of cardiovascular events. Fine needle biopsy and contrast enhanced harmonic endoscopic ultrasonography are of help for the diagnosis of autoimmune pancreatitis and its differential diagnosis with pancreatic cancer.

Correlation between the degree of pancreatic fibrosis and pancreatic secretion of bicarbonate in patients with early morphological changes of chronic pancreatitis

Correlation between the degree of pancreatic fibrosis and pancreatic secretion of bicarbonate in patients with early morphological changes of chronic pancreatitis

Characterization of pancreatic ductal fluid and bicarbonate secretion in wild type ferrets

Characterization of pancreatic ductal fluid and bicarbonate secretion in wild type ferrets

Spontaneous Pancreatitis Caused by Tissue-Specific Gene Ablation of Hhex in Mice.

Background & AimsPerturbations in pancreatic ductal bicarbonate secretion cause chronic pancreatitis. The physiologic mechanism of ductal secretion is known, but its transcriptional control is not. We determine the role of the transcription factor hematopoietically expressed homeobox protein (Hhex) in ductal secretion and pancreatitis.MethodsWe derived mice with pancreas-specific, Cre-mediated Hhex gene ablation to determine the requirement of Hhex in the pancreatic duct in early life and in adult stages. Histologic and immunostaining analyses were used to detect the presence of pathology. Pancreatic primary ductal cells were isolated to discover differentially expressed transcripts upon acute Hhex ablation on a cell autonomous level.ResultsHhex protein was detected throughout the embryonic and adult ductal trees. Ablation of Hhex in pancreatic progenitors resulted in postnatal ductal ectasia associated with acinar-to-ductal metaplasia, a progressive phenotype that ultimately resulted in chronic pancreatitis. Hhex ablation in adult mice, however, did not cause any detectable pathology. Ductal ectasia in young mice did not result from perturbation of expression of Hnf6, Hnf1β, or the primary cilia genes. RNA-seq analysis of Hhex-ablated pancreatic primary ductal cells showed mRNA levels of the G-protein coupled receptor natriuretic peptide receptor 3 (Npr3), implicated in paracrine signaling, up-regulated by 4.70-fold.ConclusionsAlthough Hhex is dispensable for ductal cell function in the adult, ablation of Hhex in pancreatic progenitors results in pancreatitis. Our data highlight the critical role of Hhex in maintaining ductal homeostasis in early life and support ductal hypersecretion as a novel etiology of pediatric chronic pancreatitis.

Pancreatic epithelial fluid and bicarbonate secretion is significantly elevated in the absence of serotonin in mice

Pancreatic epithelial fluid and bicarbonate secretion is significantly elevated in the absence of serotonin in mice

Secretin

This review describes the history of secretin discovery, identification, purification, and structural determination; cloning of secretin and its receptor; synthetic secretin; and highly specific and sensitive radioimmunoassay to define the characteristic physiological role on postprandial pancreatic fluid and bicarbonate secretion, which requires robust potentiation by cholecystokinin. Secretin plays a key role in the negative and positive regulatory mechanisms of exocrine pancreatic secretion. Secretin-releasing peptides were discovered in duodenal acid perfusates of both rat and dog and in canine pancreatic juice. The release and action of secretin and secretin-releasing peptides are in part mediated via vagovagal reflex mechanism involving afferent sensory neurons in proximal intestine and efferent cholinergic neurons in the pancreas. Besides acetylcholine, many neurotransmitters or neuromodulators influence release and action of secretin. The action of secretin in the pancreas depends on insulin, which also suppresses local release of somatostatin and pancreatic polypeptide. Thus, release and action of secretin are mediated via neurohormonal interaction. Clinical conditions with hypersecretinemia and hyposecretinemia are discussed. Synthetic human secretin is used for studies of exocrine pancreatic secretion, secretin-enhanced magnetic resonance cholangiopancreatography combined with exocrine pancreatic function test and diagnosis of gastrinoma syndrome. Therapeutic use of secretin is considered for the relief of severe pain in chronic pancreatitis.

The Role of Pancreatic Ductal Secretion in Protection Against Acute Pancreatitis in Mice*

A common potentially fatal disease of the pancreas is acute pancreatitis, for which there is no treatment. Most studies of this disorder focus on the damage to acinar cells since they are assumed to be the primary target of multiple stressors affecting the pancreas. However, increasing evidence suggests that the ducts may also have a crucial role in induction of the disease. To test this hypothesis, we sought to determine the specific role of the duct in the induction of acute pancreatitis using well-established disease models and mice with deletion of the Na/H exchanger regulatory factor-1 that have selectively impaired ductal function. Randomized animal study. Animal research laboratory. Wild-type and Na/H exchanger regulatory factor-1 knockout mice. Acute necrotizing pancreatitis was induced by i.p. administration of cerulein or by intraductal administration of sodium taurocholate. The pancreatic expression of Na/H exchanger regulatory factor-1 and cystic fibrosis transmembrane conductance regulator (a key player in the control of ductal secretion) was analyzed by immunohistochemistry. In vivo pancreatic ductal secretion was studied in anesthetized mice. Functions of pancreatic acinar and ductal cells as well as inflammatory cells were analyzed in vitro. Deletion of Na/H exchanger regulatory factor-1 resulted in gross mislocalization of cystic fibrosis transmembrane conductance regulator, causing marked reduction in pancreatic ductal fluid and bicarbonate secretion. Importantly, deletion of Na/H exchanger regulatory factor-1 had no deleterious effect on functions of acinar and inflammatory cells. Deletion of Na/H exchanger regulatory factor-1, which specifically impaired ductal function, increased the severity of acute pancreatitis in the two mouse models tested. Our findings provide the first direct evidence for the crucial role of ductal secretion in protecting the pancreas from acute pancreatitis and strongly suggest that improved ductal function should be an important modality in prevention and treatment of the disease.

Intraductal acidosis in acute biliary pancreatitis

Acute pancreatitis recently became the most common cause for hospitalization among gastrointestinal diseases. There is no specific therapy against the disease due to insufficient understanding of pathogenesis. Animal and in vitro models indicated that reduced pancreatic ducal bicarbonate secretion and consequent intraductal acidosis is an early event in acute pancreatitis, but human data are lacking. Therefore, our aim was to determine the luminal pH in the main pancreatic duct during acute pancreatitis in humans.Intraductal pH was measured in patients with acute biliary pancreatitis (n = 6) during endoscopic retrograde cholangio-pancreatography. Patients with common bile stones without pancreatitis (n = 5) and a patient with an adenoma of the papilla of Vater served as controls. The luminal pH was significantly lower in the group of acute biliary pancreatitis vs. controls (6.97 ± 0.13 vs. 7.79 ± 0.20).Our brief report shows for the first time that there is marked intraductal acidosis in acute biliary pancreatitis, which seems to worsen with time. Further clinical trials are needed to determine the exact roles of reduced intraductal pH in ABP.

Transepithelial Bicarbonate Secretion: Lessons from the Pancreas

Many cystic fibrosis transmembrane conductance regulator (CFTR)-expressing epithelia secrete bicarbonate (HCO(3)(-))-containing fluids. Recent evidence suggests that defects in epithelial bicarbonate secretion are directly involved in the pathogenesis of cystic fibrosis, in particular by building up hyperviscous mucus in the ductal structures of the lung and pancreas. Pancreatic juice is one of the representative fluids that contain a very high concentration of bicarbonate among bodily fluids that are secreted from CFTR-expressing epithelia. We introduce up-to-date knowledge on the basic principles of transepithelial bicarbonate transport by showing the mechanisms involved in pancreatic bicarbonate secretion. The model of pancreatic bicarbonate secretion described herein may also apply to other exocrine epithelia. As a central regulator of bicarbonate transport at the apical membrane, CFTR plays an essential role in both direct and indirect bicarbonate secretion. The major role of CFTR in bicarbonate secretion would be variable depending on the tissue and cell type. For example, in epithelial cells that produce a low concentration of bicarbonate-containing fluid (up to 80 mm), either CFTR-dependent Cl(-)/HCO(3)(-) exchange or CFTR anion channel with low bicarbonate permeability would be sufficient to generate such fluid. However, in cells that secrete high-bicarbonate-containing fluids, a highly selective CFTR bicarbonate channel activity is required. Therefore, understanding the molecular mechanism of transepithelial bicarbonate transport and the role of CFTR in each specific epithelium will provide therapeutic strategies to recover from epithelial defects induced by hyposecretion of bicarbonate in cystic fibrosis.

Ethanol and non-oxidative Ethanol metabolites decrease the intracellular ATP level and the bicarbonate secretion in pancreatic ductal epithelial cell line

Introduction: Pancreatic ductal epithelial cells (PDEC) have important roles in the maintenance of pancreatic integrity and bicarbonate secretion. Excessive ethanol consumption is one of the most common causes of acute pancreatitis, but the effects of ethanol metabolites on PDEC are unknown. The aim of this study was to characterize the effects of ethanol and its non-oxidative metabolites on PDEC.