Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 84
Filter
Add more filters

Country/Region as subject
Publication year range
1.
J Biol Chem ; 296: 100171, 2021.
Article in English | MEDLINE | ID: mdl-33298523

ABSTRACT

The ion channels Piezo1 and TRPV4 have both, independently, been implicated in high venous pressure- and fluid shear stress-induced vascular hyperpermeability in endothelial cells. However, the mechanism by which Piezo1 and TRPV4 channels execute the same function is poorly understood. Here we demonstrate that Piezo1 regulates TRPV4 channel activation in endothelial cells and that Piezo1-mediated TRPV4 channel opening is a function of the strength and duration of fluid shear stress. We first confirmed that either fluid shear stress or the Piezo1 agonist, Yoda1, led to an elevation in intracellular calcium ([Ca2+]i) and that application of the Piezo1 antagonist, GsMTx4, completely blocked this change. We discovered that high and prolonged shear stress caused sustained [Ca2+]i elevation that was blocked by inhibition of TRPV4 channel opening. Moreover, Piezo1 stimulated TRPV4 opening through activation of phospholipase A2. TRPV4-dependent sustained [Ca2+]i elevation was responsible for fluid shear stress-mediated and Piezo1-mediated disruption of adherens junctions and actin remodeling. Blockade of TRPV4 channels with the selective TRPV4 blocker, HC067047, prevented the loss of endothelial cell integrity and actin disruption induced by Yoda1 or shear stress and prevented Piezo1-induced monocyte adhesion to endothelial cell monolayers. These findings demonstrate that Piezo1 activation by fluid shear stress initiates a calcium signal that causes TRPV4 opening, which in turn is responsible for the sustained phase calcium elevation that triggers pathological events in endothelial cells. Thus, deleterious effects of shear stress are initiated by Piezo1 but require TRPV4.


Subject(s)
Endothelial Cells/metabolism , Endothelial Cells/pathology , Ion Channels/metabolism , TRPV Cation Channels/metabolism , Adherens Junctions/metabolism , Calcium Signaling , Cells, Cultured , Humans , Mechanotransduction, Cellular , Stress, Mechanical , Venous Pressure
2.
Am J Physiol Gastrointest Liver Physiol ; 323(5): G420-G427, 2022 11 01.
Article in English | MEDLINE | ID: mdl-36126221

ABSTRACT

It has previously been shown that current smoking is protective against endoscopic retrograde cholangiopancreatography (ERCP)-induced acute pancreatitis, but the mechanism of this effect was not identified. We tested the hypothesis that nicotine is the active factor in this protection in a mouse model of ERCP. Pretreatment with nicotine dose dependently inhibited acute pancreatitis caused by infusion of ERCP contrast solution into the main pancreatic duct in mice. 3-2,4-Dimethoxybenzylidene anabaseine (GTS-21), a specific partial agonist of the α7 nicotinic cholinergic receptor (α7nAChR), also protected the pancreas against ERCP-induced acute pancreatitis. The effects of GTS-21 were abolished by pretreatment with the nicotinic receptor antagonist mecamylamine. Surgical splenectomy performed 7 days before ERCP-induced pancreatitis blocked the protective effects of GTS-21. Intravenous injection of a crude preparation of total splenocytes prepared from mice pretreated with GTS-21 inhibited ERCP-induced pancreatitis; splenocytes from mice treated with vehicle had no effect. When T cells were removed from the crude GTS-21-treated splenocyte preparation by immunomagnetic separation, the remaining non-T-cell splenocytes did not protect against ERCP-induced acute pancreatitis. We conclude that nicotine protects against ERCP-induced acute pancreatitis and that splenic T cells are required for this effect. Stimulation of α7 nicotinic cholinergic receptors may protect against ERCP-induced acute pancreatitis and may also be a novel approach to therapeutic reversal of ongoing acute pancreatitis.NEW & NOTEWORTHY Epidemiological evidence indicated that acute smoking reduced the risk of endoscopic retrograde cholangiopancreatography (ERCP)-induced pancreatitis, but the mechanism has remained elusive. The current findings indicate the nicotine reduces the severity of ERCP-induced pancreatitis by stimulating a population of splenic T cells that exert a protective effect on the pancreas. These findings raise the possibility that nicotinic agonists might be useful in treating pancreatitis.


Subject(s)
Cholangiopancreatography, Endoscopic Retrograde , Pancreatitis , Mice , Animals , Cholangiopancreatography, Endoscopic Retrograde/adverse effects , Pancreatitis/etiology , Nicotine , Mecamylamine , Nicotinic Agonists/pharmacology , Acute Disease , alpha7 Nicotinic Acetylcholine Receptor , Spleen , T-Lymphocytes
3.
Am J Physiol Gastrointest Liver Physiol ; 322(6): G561-G570, 2022 06 01.
Article in English | MEDLINE | ID: mdl-35293263

ABSTRACT

Proper mitochondrial function and adequate cellular ATP are necessary for normal pancreatic protein synthesis and sorting, maintenance of intracellular organelles and enzyme secretion. Inorganic phosphate is required for generating ATP and its limited availability may lead to reduced ATP production causing impaired Ca2+ handling, defective autophagy, zymogen activation, and necrosis, which are all features of acute pancreatitis. We hypothesized that reduced dietary phosphate leads to hypophosphatemia and exacerbates pancreatitis severity of multiple causes. We observed that mice fed a low-phosphate diet before the induction of pancreatitis by either repeated caerulein administration or pancreatic duct injection as a model of pressure-induced pancreatitis developed hypophosphatemia and exhibited more severe pancreatitis than normophosphatemic mice. Pancreatitis severity was significantly reduced in mice treated with phosphate. In vitro modeling of secretagogue- and pressure-induced pancreatic injury was evaluated in isolated pancreatic acini using cholecystokinin and the mechanoreceptor Piezo1 agonist, Yoda1, under low and normal phosphate conditions. Isolated pancreatic acini were more sensitive to cholecystokinin- and Yoda1-induced acinar cell damage and mitochondrial dysfunction under low-phosphate conditions and improved following phosphate supplementation. Importantly, even mice on a normal phosphate diet exhibited less severe pancreatitis when treated with supplemental phosphate. Thus, hypophosphatemia sensitizes animals to pancreatitis and phosphate supplementation reduces pancreatitis severity. These appear to be direct effects of phosphate on acinar cells through restoration of mitochondrial function. We propose that phosphate administration may be useful in the treatment of acute pancreatitis.NEW & NOTEWORTHY Impaired ATP synthesis disrupts acinar cell homeostasis and is an early step in pancreatitis. We report that reduced phosphate availability impairs mitochondrial function and worsens pancreatic injury. Phosphate supplementation improves mitochondrial function and protects against experimental pancreatitis, raising the possibility that phosphate supplementation may be useful in treating pancreatitis.


Subject(s)
Hypophosphatemia , Pancreatitis , Acute Disease , Adenosine Triphosphate/metabolism , Animals , Ceruletide/pharmacology , Cholecystokinin/metabolism , Hypophosphatemia/metabolism , Ion Channels/metabolism , Mice , Pancreas/metabolism , Pancreatitis/chemically induced , Pancreatitis/drug therapy , Pancreatitis/metabolism , Phosphates/metabolism
4.
Gastroenterology ; 161(3): 982-995.e2, 2021 09.
Article in English | MEDLINE | ID: mdl-34051238

ABSTRACT

BACKGROUND & AIMS: Heavy alcohol consumption is a common cause of acute pancreatitis; however, alcohol abuse does not always result in clinical pancreatitis. As a consequence, the factors responsible for alcohol-induced pancreatitis are not well understood. In experimental animals, it has been difficult to produce pancreatitis with alcohol. Clinically, alcohol use predisposes to hypophosphatemia, and hypophosphatemia has been observed in some patients with acute pancreatitis. Because of abundant protein synthesis, the pancreas has high metabolic demands, and reduced mitochondrial function leads to organelle dysfunction and pancreatitis. We proposed, therefore, that phosphate deficiency might limit adenosine triphosphate synthesis and thereby contribute to alcohol-induced pancreatitis. METHODS: Mice were fed a low-phosphate diet (LPD) before orogastric administration of ethanol. Direct effects of phosphate and ethanol were evaluated in vitro in isolated mouse pancreatic acini. RESULTS: LPD reduced serum phosphate levels. Intragastric administration of ethanol to animals maintained on an LPD caused severe pancreatitis that was ameliorated by phosphate repletion. In pancreatic acinar cells, low-phosphate conditions increased susceptibility to ethanol-induced cellular dysfunction through decreased bioenergetic stores, specifically affecting total cellular adenosine triphosphate and mitochondrial function. Phosphate supplementation prevented ethanol-associated cellular injury. CONCLUSIONS: Phosphate status plays a critical role in predisposition to and protection from alcohol-induced acinar cell dysfunction and the development of acute alcohol-induced pancreatitis. This finding may explain why pancreatitis develops in only some individuals with heavy alcohol use and suggests a potential novel therapeutic approach to pancreatitis. Finally, an LPD plus ethanol provides a new model for studying alcohol-associated pancreatic injury.


Subject(s)
Energy Metabolism , Hypophosphatemia/complications , Mitochondria/metabolism , Pancreas/metabolism , Pancreatitis, Alcoholic/metabolism , Phosphates/deficiency , Adenosine Triphosphate/metabolism , Animals , Disease Models, Animal , Ethanol , Hypophosphatemia/metabolism , Hypophosphatemia/prevention & control , Male , Mice, Inbred C57BL , Mitochondria/pathology , Pancreas/pathology , Pancreatitis, Alcoholic/chemically induced , Pancreatitis, Alcoholic/pathology , Pancreatitis, Alcoholic/prevention & control , Phosphates/administration & dosage , Severity of Illness Index , Tissue Culture Techniques
5.
Acta Neuropathol ; 141(4): 547-564, 2021 04.
Article in English | MEDLINE | ID: mdl-33641009

ABSTRACT

α-Synuclein aggregation underlies pathological changes in Lewy body dementia. Recent studies highlight structural variabilities associated with α-synuclein aggregates in patient populations. Here, we develop a quantitative real-time quaking-induced conversion (qRT-QuIC) assay to measure permissive α-synuclein fibril-templating activity in tissues and cerebrospinal fluid (CSF). The assay is anchored through reference panels of stabilized ultra-short fibril particles. In humanized α-synuclein transgenic mice, qRT-QuIC identifies differential levels of fibril activity across the brain months before the deposition of phosphorylated α-synuclein in susceptible neurons. α-Synuclein fibril activity in cortical brain extracts from dementia with Lewy bodies (DLB) correlates with activity in matched ventricular CSF. Elevated α-synuclein fibril activity in CSF corresponds to reduced survival in DLB. α-Synuclein fibril particles amplified from cases with high fibril activity show superior templating in the formation of new inclusions in neurons relative to the same number of fibril particles amplified from DLB cases with low fibril activity. Our results highlight a previously unknown broad heterogeneity of fibril-templating activities in DLB that may contribute to disease phenotypes. We predict that quantitative assessments of fibril activities in CSF that correlate to fibril activities in brain tissue will help stratify patient populations as well as measure therapeutic responses to facilitate the development of α-synuclein-targeted therapeutics.


Subject(s)
Chemistry Techniques, Analytical/methods , Lewy Body Disease/metabolism , Lewy Body Disease/pathology , alpha-Synuclein/metabolism , Aged , Aged, 80 and over , Animals , Female , Humans , Male , Mice , Middle Aged , Phenotype , alpha-Synuclein/analysis
6.
Pancreatology ; 24(2): 323, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38199823
7.
Hum Mol Genet ; 24(3): 609-24, 2015 Feb 01.
Article in English | MEDLINE | ID: mdl-25217574

ABSTRACT

In the mammalian inner ear, bicellular and tricellular tight junctions (tTJs) seal the paracellular space between epithelial cells. Tricellulin and immunoglobulin-like (Ig-like) domain containing receptor 1 (ILDR1, also referred to as angulin-2) localize to tTJs of the sensory and non-sensory epithelia in the organ of Corti and vestibular end organs. Recessive mutations of TRIC (DFNB49) encoding tricellulin and ILDR1 (DFNB42) cause human nonsyndromic deafness. However, the pathophysiology of DFNB42 deafness remains unknown. ILDR1 was recently reported to be a lipoprotein receptor mediating the secretion of the fat-stimulated cholecystokinin (CCK) hormone in the small intestine, while ILDR1 in EpH4 mouse mammary epithelial cells in vitro was shown to recruit tricellulin to tTJs. Here we show that two different mouse Ildr1 mutant alleles have early-onset severe deafness associated with a rapid degeneration of cochlear hair cells (HCs) but have a normal endocochlear potential. ILDR1 is not required for recruitment of tricellulin to tTJs in the cochlea in vivo; however, tricellulin becomes mislocalized in the inner ear sensory epithelia of ILDR1 null mice after the first postnatal week. As revealed by freeze-fracture electron microscopy, ILDR1 contributes to the ultrastructure of inner ear tTJs. Taken together, our data provide insight into the pathophysiology of human DFNB42 deafness and demonstrate that ILDR1 is crucial for normal hearing by maintaining the structural and functional integrity of tTJs, which are critical for the survival of auditory neurosensory HCs.


Subject(s)
Hair Cells, Auditory/pathology , Hearing Loss, Sensorineural/pathology , Receptors, Cell Surface/genetics , Tight Junctions/pathology , Animals , Disease Models, Animal , Hair Cells, Auditory/metabolism , Hearing Loss, Sensorineural/genetics , Hearing Loss, Sensorineural/metabolism , Humans , MARVEL Domain Containing 2 Protein/metabolism , Mice , Mutation , Receptors, Cell Surface/metabolism , Tight Junctions/metabolism
8.
9.
Pancreatology ; 16(1): 83-94, 2016.
Article in English | MEDLINE | ID: mdl-26620965

ABSTRACT

DESCRIPTION: Pain in patients with chronic pancreatitis (CP) remains the primary clinical complaint and source of poor quality of life. However, clear guidance on evaluation and treatment is lacking. METHODS: Pancreatic Pain working groups reviewed information on pain mechanisms, clinical pain assessment and pain treatment in CP. Levels of evidence were assigned using the Oxford system, and consensus was based on GRADE. A consensus meeting was held during PancreasFest 2012 with substantial post-meeting discussion, debate, and manuscript refinement. RESULTS: Twelve discussion questions and proposed guidance statements were presented. Conference participates concluded: Disease Mechanism: Pain etiology is multifactorial, but data are lacking to effectively link symptoms with pathologic feature and molecular subtypes. Assessment of Pain: Pain should be assessed at each clinical visit, but evidence to support an optimal approach to assessing pain character, frequency and severity is lacking. MANAGEMENT: There was general agreement on the roles for endoscopic and surgical therapies, but less agreement on optimal patient selection for medical, psychological, endoscopic, surgical and other therapies. CONCLUSIONS: Progress is occurring in pain biology and treatment options, but pain in patients with CP remains a major problem that is inadequately understood, measured and managed. The growing body of information needs to be translated into more effective clinical care.


Subject(s)
Analgesics/therapeutic use , Pain/drug therapy , Pain/etiology , Pancreatitis, Chronic/complications , Humans , Practice Guidelines as Topic
10.
Eur J Clin Invest ; 45(3): 237-46, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25641074

ABSTRACT

BACKGROUND: Regular gall bladder contraction reduces bile stasis and prevents gallstone formation. Intraduodenal administration of exogenous pancreatic secretory trypsin inhibitor-I (PSTI-I, also known as monitor peptide) causes cholecystokinin (CCK) secretion. DESIGN: We proposed that stimulation of CCK release by PSTI would produce gall bladder contraction and prevent gallstones in mice fed a lithogenic diet. Therefore, we tested the effect of overexpression of rat PSTI-I in pancreatic acinar cells on plasma CCK levels and gall bladder function in a transgenic mouse line (TgN[Psti1]; known hereafter as PSTI-I tg). RESULTS: Importantly, PSTI tg mice had elevated fasting and fed plasma CCK levels compared to wild-type (WT) mice. Only mice fed the lithogenic diet developed gallstones. Both fasting and stimulated plasma CCK levels were substantially reduced in both WT and PSTI-I tg mice on the lithogenic diet. Moreover, despite higher CCK levels PSTI-I tg animals developed more gallstones than WT animals. CONCLUSIONS: Together with the previously observed decrease in CCK-stimulated gall bladder emptying in mice fed a lithogenic diet, our findings suggest that a lithogenic diet causes gallstone formation by impaired CCK secretion in addition to reduced gall bladder sensitivity to CCK.


Subject(s)
Cholecystokinin/metabolism , Gallstones/prevention & control , Intercellular Signaling Peptides and Proteins/metabolism , Acinar Cells/metabolism , Animals , Cholecystitis/pathology , Diet , Gallbladder/pathology , Gallbladder Emptying/physiology , Gallstones/physiopathology , Intercellular Signaling Peptides and Proteins/genetics , Lipid Metabolism/physiology , Male , Mice, Inbred C57BL , Organ Size/physiology , Pancreas/cytology , Rats , Trypsin Inhibitor, Kazal Pancreatic
11.
FASEB J ; 28(2): 891-6, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24221085

ABSTRACT

Alcohol abuse is a major cause of pancreatitis in people, but the mechanism is unknown. It has been recently demonstrated that transient receptor potential vanilloid 1 (TRPV1) activation causes neurogenic inflammation and plays an important role in acute pancreatitis. Moreover, TRPV1 is activated by ethanol. We examined the direct effects of ethanol on acute pancreatitis. Acute inflammation of the pancreas was produced by injection of ethanol and palmitoleic acid (POA), a nonoxidative metabolite of ethanol, in wild-type C57BL/6J mice and Trpv1-knockout C57BL/6J mice. Inflammatory indexes were analyzed 24 h later. Injection of ethanol + POA produced acute pancreatitis indicated by significant increases in histopathological damage, serum amylase levels, and pancreatic MPO concentrations (P<0.05-0.001). All parameters of pancreatitis were blocked by pretreatment with the TRPV1 antagonist drug AMG9810. In addition, ethanol + POA administration to Trpv1knockout mice did not produce pancreatic inflammation. Treatment with vehicle, ethanol alone, or POA alone had no inflammatory effects. TRPV1 partially mediates inflammation induced by ethanol + POA in the mouse pancreas, consistent with the ability of ethanol to activate TRPV1. We propose that ethanol may contribute to alcohol-induced pancreatitis by a neurogenic mechanism.


Subject(s)
Acrylamides/pharmacology , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Ethanol/pharmacology , Pancreatitis/chemically induced , Pancreatitis/metabolism , TRPV Cation Channels/metabolism , Animals , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Pancreatitis/pathology , TRPV Cation Channels/antagonists & inhibitors , TRPV Cation Channels/genetics
12.
FASEB J ; 27(3): 1191-202, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23233532

ABSTRACT

Genetic variants in the fatty acid (FA) translocase FAT/CD36 associate with abnormal postprandial lipids and influence risk for the metabolic syndrome. CD36 is abundant on apical enterocyte membranes in the proximal small intestine, where it facilitates FA uptake and FA-initiated signaling. We explored whether CD36 signaling influences FA-mediated secretion of cholecystokinin (CCK) and secretin, peptides released by enteroendocrine cells (EECs) in the duodenum/jejunum, which regulate events important for fat digestion and homeostasis. CD36 was immunodetected on apical membranes of secretin- and CCK-positive EECs and colocalized with cytosolic granules. Intragastric lipid administration to CD36 mice released less secretin (-60%) and CCK (-50%) compared with wild-type mice. Likewise, diminished secretin and CCK responses to FA were observed with CD36 intestinal segments in vitro, arguing against influence of alterations in fat absorption. Signaling mechanisms underlying peptide release were examined in STC-1 cells stably expressing human CD36 or a signaling-impaired mutant (CD36K/A). FA stimulation of cells expressing CD36 (vs. vector or CD36K/A) released more secretin (3.5- to 4-fold) and CCK (2- to 3-fold), generated more cAMP (2- to 2.5-fold), and enhanced protein kinase A activation. Protein kinase A inhibition (H-89) blunted secretin (80%) but not CCK release, which was reduced (50%) by blocking of calmodulin kinase II (KN-62). Coculture of STC-1 cells with Caco-2 cells stably expressing CD36 did not alter secretin or CCK release, consistent with a minimal effect of adjacent enterocytes. In summary, CD36 is a major mediator of FA-induced release of CCK and secretin. These peptides contribute to the role of CD36 in fat absorption and to its pleiotropic metabolic effects.


Subject(s)
CD36 Antigens/metabolism , Cholecystokinin/metabolism , Duodenum/metabolism , Enteroendocrine Cells/metabolism , Fatty Acids/metabolism , Jejunum/metabolism , Secretin/metabolism , Animals , CD36 Antigens/genetics , Caco-2 Cells , Cholecystokinin/genetics , Cyclic AMP-Dependent Protein Kinases/metabolism , Duodenum/cytology , Enteroendocrine Cells/cytology , Enzyme Activation , Fatty Acids/genetics , Humans , Jejunum/cytology , Mice , Mice, Knockout , Secretin/genetics , Signal Transduction/physiology
13.
FASEB J ; 27(12): 5022-33, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24043261

ABSTRACT

It has been hypothesized that the peripheral taste system may be modulated in the context of an animal's metabolic state. One purported mechanism for this phenomenon is that circulating gastrointestinal peptides modulate the functioning of the peripheral gustatory system. Recent evidence suggests endocrine signaling in the oral cavity can influence food intake (FI) and satiety. We hypothesized that these hormones may be affecting FI by influencing taste perception. We used immunohistochemistry along with genetic knockout models and the specific reconstitution of peptide YY (PYY) in saliva using gene therapy protocols to identify a role for PYY signaling in taste. We show that PYY is expressed in subsets of taste cells in murine taste buds. We also show, using brief-access testing with PYY knockouts, that PYY signaling modulates responsiveness to bitter-tasting stimuli, as well as to lipid emulsions. We show that salivary PYY augmentation, via viral vector therapy, rescues behavioral responsiveness to a lipid emulsion but not to bitter stimuli and that this response is likely mediated via activation of Y2 receptors localized apically in taste cells. Our findings suggest distinct functions for PYY produced locally in taste cells vs. that circulating systemically.


Subject(s)
Peptide YY/metabolism , Satiety Response , Taste , Animals , Eating , Mice , Mice, Knockout , Peptide YY/genetics , Receptors, Neuropeptide Y/genetics , Receptors, Neuropeptide Y/metabolism , Taste Buds/metabolism
14.
Curr Opin Gastroenterol ; 30(5): 490-4, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25003603

ABSTRACT

PURPOSE OF REVIEW: This review highlights recent progress made in the field of pancreatic secretion. RECENT FINDINGS: This review summarizes a number of recent studies demonstrating the intracellular pathways by which hormones and neural inputs regulate pancreatic exocrine and endocrine secretion. In particular, the effects of vasoactive intestinal peptide and secretin on intra-acinar cell adenosine 3',5'-cyclic monophosphate are explored. Considerable attention is paid to regulation of ß-cell function and includes studies detailing the mechanisms of regulation of insulin by somatostatin, serotonin, and melanocortins. These studies emphasize the critical role that hormonal, paracrine, and neural factors play in glucose homeostasis. SUMMARY: Exocrine and endocrine pancreatic secretions are regulated by hormonal and neural mechanisms, and understanding these pathways will enable the discovery and design of new and improved therapies for prevention and control of diabetes and perhaps exocrine insufficiency.


Subject(s)
Diabetes Mellitus/prevention & control , Hormones/physiology , Pancreas, Exocrine/metabolism , Blood Glucose/metabolism , Humans , Insulin/metabolism , Insulin Secretion
15.
Pancreas ; 53(1): e3-e8, 2024 Jan 01.
Article in English | MEDLINE | ID: mdl-37968112

ABSTRACT

OBJECTIVE: Phosphate is crucial for cellular repair after injury and may be important in recovery following acute pancreatitis (AP). This study aimed to evaluate the association between hypophosphatemia and severity of AP. METHODS: Patients admitted with AP between 2014-2018 were identified and their records were retrospectively reviewed. Pancreatitis severity was defined using the modified Atlanta Criteria. Hypophosphatemia was defined as phosphate <2 mg/dL and was assessed at three time points: within one day, within two days, at any time during admission. The proportion of patients who developed severe AP was compared between patients with and without hypophosphatemia. RESULTS: Of 312 patients, 30.1% (n = 94) developed severe AP. Hypophosphatemia occurred in 25.0% overall, within one day in 19.7%, and within two days in 20.0%. A higher proportion of patients with hypophosphatemia developed severe AP (overall: 47.4% vs. 24.4%, P < 0.001; one day: 47.4% vs. 23.9%, P = 0.004; two days: 42.9% vs. 24.5%, P = 0.01). Patients with hypophosphatemia within one day were also more likely to have ICU admission ( P < 0.001) and longer length of stay ( P < 0.001). CONCLUSIONS: Early hypophosphatemia during an admission for AP was associated with increased AP severity, ICU admission, and longer length of stay.


Subject(s)
Hypophosphatemia , Pancreatitis , Humans , Pancreatitis/complications , Pancreatitis/diagnosis , Pancreatitis/therapy , Retrospective Studies , Acute Disease , Severity of Illness Index , Hypophosphatemia/etiology , Hypophosphatemia/complications , Phosphates
16.
Pancreas ; 2024 May 01.
Article in English | MEDLINE | ID: mdl-38696363

ABSTRACT

OBJECTIVES: Acute pancreatitis (AP) is a complex disease representing a significant portion of gastrointestinal-related hospitalizations in the U.S. Understanding risk factors of AP might provide attractive therapeutic targets. We evaluated hypophosphatemia as a risk factor for worse outcomes in AP. METHODS: We performed a retrospective review of electronic health records of patients with AP admissions from 01/01/2012-12/31/2021 at Cedars-Sinai Medical Center, evaluating patients with serum phosphate measured within 48 hours of admission. Multivariable logistic regression modeling was employed to evaluate associations with ICU admission, AP severity, and a multivariable log-linear model was employed to examine associations with length of stay (LOS). RESULTS: Of 1,526 patients admitted for AP, 33% (499) had a serum phosphate level measured within 48 hours. Patients with hypophosphatemia were more likely to have been admitted to the ICU (AOR = 4.57; 95% CI: 2.75-7.62; P < 0.001), have a longer hospital stay (log-LOS = 0.34; SE; 0.09; 95% CI: 0.17-0.52; P < 0.001), and were more likely to have moderate or severe AP (AOR = 1.80; 95% CI: 1.16-2.80; P < 0.001) compared to those without hypophosphatemia. CONCLUSION: Serum phosphate is infrequently measured in patients with AP and shows promise as a rapid, inexpensive, and early prognostic marker for worse outcomes of AP.

17.
bioRxiv ; 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38187663

ABSTRACT

Pancreatic stellate cells (PSCs) are primarily responsible for producing the stiff tumor tissue in pancreatic ductal adenocarcinoma (PDAC). Thereby, PSCs generate a stiffness gradient between the healthy pancreas and the tumor. This gradient induces durotaxis, a form of directional cell migration driven by differential stiffness. The molecular sensors behind durotaxis are still unclear. To investigate the role of mechanosensitive ion channels in PSC durotaxis, we established a two-dimensional stiffness gradient mimicking PDAC. Using pharmacological and genetic methods, we investigated the role of the ion channels Piezo1, TRPC1, and TRPV4 in PSC durotaxis. We found that PSC migration towards a stiffer substrate is diminished by altering Piezo1 activity. Moreover, disrupting TRPC1 along with TRPV4 abolishes PSC durotaxis even when Piezo1 is functional. Hence, PSC durotaxis is optimal with an intermediary level of mechanosensitive channel activity, which we simulated using a numerically discretized mathematical model. Our findings suggest that mechanosensitive ion channels, particularly Piezo1, detect the mechanical microenvironment to guide PSC migration.

18.
Curr Opin Gastroenterol ; 29(5): 517-22, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23817137

ABSTRACT

PURPOSE OF REVIEW: Recent advances in the regulation of pancreatic secretion by secretagogues, modulatory proteins and neural pathways are discussed. RECENT FINDINGS: Downstream events involved in secretagogue stimulation of pancreatic secretion have been elucidated through characterization of the Src kinase pathway. An additional mechanism regulating vagus nerve effects on the pancreas involves Group II and III metabotropic glutamate receptors that are located presynaptically on certain vagal pancreas-projecting neurons. Hypothalamic neurons perceive glucose and regulate insulin release by direct communication with islets, and activation of proopiomelanocortin neurons by leptin enhances insulin secretion and modulates glucose but not energy homeostasis. Ghrelin and somatostatin mediate glucose-stimulated insulin secretion by differential receptor signaling that is dependent on the amount of ghrelin and state of receptor heterodimerization. Endoplasmic reticulum (ER) stress and loss-of-function mutations of a key ER stress protein are associated with disruption of membrane translocation and reduction in insulin secretion. The importance of hormones, neuropeptides, amino acids, cytokines and regulatory proteins in pancreatic secretion and the pathophysiology of type 2 diabetes are also discussed. SUMMARY: The biomolecular pathways regulating pancreatic secretions are still not fully understood. New secretagogues and mechanisms continue to be identified and this information will aid in drug discovery and development of new and improved therapy for pancreatic disorders.


Subject(s)
Islets of Langerhans/metabolism , Pancreas, Exocrine/metabolism , Hormones/physiology , Humans , Insulin/metabolism , Insulin Secretion , Islets of Langerhans/innervation , Neural Pathways/physiology , Neurotransmitter Agents/physiology , Pancreas, Exocrine/innervation , Signal Transduction/physiology , Vagus Nerve/physiology
19.
J Clin Invest ; 133(4)2023 02 15.
Article in English | MEDLINE | ID: mdl-36787251

ABSTRACT

Visceral pain associated with irritable bowel syndrome afflicts 15% of the US population. Although treatments are limited, guanylyl cyclase C (GUCY2C) agonists alleviate pain and constipation. Until now, it was assumed that the activation of GUCY2C and production of cGMP in enterocytes stimulated fluid secretion and reduced visceral sensation. The recent discovery that a subtype of enteroendocrine cells (EECs) known as neuropod cells synapse with submucosal neurons unveiled a pathway for communicating gut signals to the nervous system. In this issue of the JCI, Barton et al. report that GUCY2C is enriched in neuropod cells and is involved with sensory nerve firing. Selective deletion of GUCY2C in mouse models suggests that defective GUCY2C neuropod-cell signaling underlies visceral pain. These studies introduce possibilities for dissociating the secretory and analgesic effects of GUCY2C agonism. Although further work remains, unveiling the role of neuropod cells is a major step in understanding visceral pain.


Subject(s)
Irritable Bowel Syndrome , Visceral Pain , Mice , Animals , Receptors, Enterotoxin/metabolism , Visceral Pain/genetics , Signal Transduction/physiology , Cyclic GMP/metabolism
20.
J Clin Invest ; 133(19)2023 10 02.
Article in English | MEDLINE | ID: mdl-37781915

ABSTRACT

All cells in the body are exposed to physical force in the form of tension, compression, gravity, shear stress, or pressure. Cells convert these mechanical cues into intracellular biochemical signals; this process is an inherent property of all cells and is essential for numerous cellular functions. A cell's ability to respond to force largely depends on the array of mechanical ion channels expressed on the cell surface. Altered mechanosensing impairs conscious senses, such as touch and hearing, and unconscious senses, like blood pressure regulation and gastrointestinal (GI) activity. The GI tract's ability to sense pressure changes and mechanical force is essential for regulating motility, but it also underlies pain originating in the GI tract. Recent identification of the mechanically activated ion channels Piezo1 and Piezo2 in the gut and the effects of abnormal ion channel regulation on cellular function indicate that these channels may play a pathogenic role in disease. Here, we discuss our current understanding of mechanically activated Piezo channels in the pathogenesis of pancreatic and GI diseases, including pancreatitis, diabetes mellitus, irritable bowel syndrome, GI tumors, and inflammatory bowel disease. We also describe how Piezo channels could be important targets for treating GI diseases.


Subject(s)
Gastrointestinal Diseases , Mechanotransduction, Cellular , Humans , Ion Channels/genetics , Ion Channels/metabolism , Cell Membrane/metabolism , Gastrointestinal Diseases/genetics
SELECTION OF CITATIONS
SEARCH DETAIL