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The Impact of α-Adrenoceptors in the Regulation of the Hypotonicity-Induced Increase in Duodenal Mucosal Permeability In Vivo. Pharmaceutics 2021; 13:pharmaceutics13122096. [PMID: 34959377 PMCID: PMC8706031 DOI: 10.3390/pharmaceutics13122096] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/18/2021] [Accepted: 12/03/2021] [Indexed: 12/12/2022] Open
Abstract
The duodenal mucosa is regularly exposed to a low osmolality, and recent experiments suggest that hypotonicity increases mucosal permeability in an osmolality-dependent manner. The aim was to examine whether the sympathetic nervous system, via action on α-adrenoceptors, affects the hypotonicity-induced increase in duodenal mucosal permeability. The duodenum of anaesthetised rats was perfused in vivo with a 50 mM NaCl solution in the presence of adrenergic α-adrenoceptor drugs. Studied were the effects on mucosal permeability (blood-to-lumen clearance of 51Cr-EDTA), arterial blood pressure, luminal alkalinisation, transepithelial fluid flux, and motility. Hypotonicity induced a six-fold increase in mucosal permeability, a response that was reversible and repeatable. The α2-adrenoceptor agonist clonidine abolished the hypotonicity-induced increase in mucosal permeability, reduced arterial blood pressure, inhibited duodenal motility, and decreased luminal alkalinisation. The α2-adrenoceptor antagonists, yohimbine and idazoxan, prevented the inhibitory effect of clonidine on the hypotonicity-induced increase in mucosal permeability. The α1-agonist phenylephrine or the α1-antagonist prazosin elicited their predicted effect on blood pressure but did not affect the hypotonicity-induced increase in mucosal permeability. None of the α1- or α2-adrenoceptor drugs changed the hypotonicity-induced net fluid absorption. In conclusion, stimulation of the adrenergic α2-adrenoceptor prevents the hypotonicity-induced increase in mucosal permeability, suggesting that the sympathetic nervous system has the capability to regulate duodenal mucosal permeability.
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Rousou C, Schuurmans CCL, Urtti A, Mastrobattista E, Storm G, Moonen C, Kaarniranta K, Deckers R. Ultrasound and Microbubbles for the Treatment of Ocular Diseases: From Preclinical Research towards Clinical Application. Pharmaceutics 2021; 13:pharmaceutics13111782. [PMID: 34834196 PMCID: PMC8624665 DOI: 10.3390/pharmaceutics13111782] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/08/2021] [Accepted: 10/09/2021] [Indexed: 12/26/2022] Open
Abstract
The unique anatomy of the eye and the presence of various biological barriers make efficacious ocular drug delivery challenging, particularly in the treatment of posterior eye diseases. This review focuses on the combination of ultrasound and microbubbles (USMB) as a minimally invasive method to improve the efficacy and targeting of ocular drug delivery. An extensive overview is given of the in vitro and in vivo studies investigating the mechanical effects of ultrasound-driven microbubbles aiming to: (i) temporarily disrupt the blood–retina barrier in order to enhance the delivery of systemically administered drugs into the eye, (ii) induce intracellular uptake of anticancer drugs and macromolecules and (iii) achieve targeted delivery of genes, for the treatment of ocular malignancies and degenerative diseases. Finally, the safety and tolerability aspects of USMB, essential for the translation of USMB to the clinic, are discussed.
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Affiliation(s)
- Charis Rousou
- Departments of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Heidelberglaan 8, 3584 CS Utrecht, The Netherlands; (C.C.L.S.); (E.M.); (G.S.)
- Division of Imaging and Oncology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands; (C.M.); (R.D.)
- Correspondence:
| | - Carl C. L. Schuurmans
- Departments of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Heidelberglaan 8, 3584 CS Utrecht, The Netherlands; (C.C.L.S.); (E.M.); (G.S.)
- Department of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Heidelberglaan 8, 3584 CS Utrecht, The Netherlands
| | - Arto Urtti
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70210 Kuopio, Finland;
- Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
- Institute of Chemistry, St. Petersburg State University, Universitetskii Pr. 26, Petrodvorets, 198504 St. Petersburg, Russia
| | - Enrico Mastrobattista
- Departments of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Heidelberglaan 8, 3584 CS Utrecht, The Netherlands; (C.C.L.S.); (E.M.); (G.S.)
| | - Gert Storm
- Departments of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Heidelberglaan 8, 3584 CS Utrecht, The Netherlands; (C.C.L.S.); (E.M.); (G.S.)
- Department of Biomaterials Science and Technology, University of Twente, 7500 AE Enschede, The Netherlands
- Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Chrit Moonen
- Division of Imaging and Oncology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands; (C.M.); (R.D.)
| | - Kai Kaarniranta
- Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, 70029 Kuopio, Finland;
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland
| | - Roel Deckers
- Division of Imaging and Oncology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands; (C.M.); (R.D.)
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Morgan BA, Niinivaara E, Xing Z, Thompson MR, Cranston ED. Validation of a diffusion-based single droplet drying model for encapsulation of a viral-vectored vaccine using an acoustic levitator. Int J Pharm 2021; 605:120806. [PMID: 34144140 DOI: 10.1016/j.ijpharm.2021.120806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/11/2021] [Accepted: 06/13/2021] [Indexed: 11/18/2022]
Abstract
Development of thermally stable spray dried viral-vectored vaccine powders is dependent on the selection of a proper excipient or excipient blend for encapsulation, which can be a time and resource intensive process. In this work, a diffusion-based droplet drying model was developed to compute droplet drying time, size, and component distribution. The model predictions were validated using an acoustic levitator to dry droplets containing protein-coated or fluorescently labelled silica nanoparticles (as adenoviral vector analogues) and a range of excipient blends. Surface morphology of the dried particles was characterized by atomic force microscopy and the distribution of silica nanoparticles was quantified by confocal microscopy. The modelled distributions of adenovirus agreed with the microscopy results for three mannitol/dextran excipient blends with varying molecular weight dextrans, verifying the equations and assumptions of the model. Viral vector activity data for adenovirus in a range of (poly)saccharide/sugar alcohol formulations were also compared to the model outputs, suggesting that viral activity decreases when the model predicts increasing adenovirus concentrations near the air-solid interface. Using a validated model with excipient property inputs that are readily available in the literature can facilitate the development of viral-vectored vaccines by identifying promising excipients without the need for experimentation.
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Affiliation(s)
- Blair A Morgan
- Department of Chemical Engineering, McMaster University, Hamilton, Ontario L8S 4L7, Canada
| | - Elina Niinivaara
- Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada; Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, FI-0076 Aalto, Espoo, Finland
| | - Zhou Xing
- McMaster Immunology Research Centre and Department of Medicine, McMaster University, Hamilton, Ontario L8S 4L7, Canada
| | - Michael R Thompson
- Department of Chemical Engineering, McMaster University, Hamilton, Ontario L8S 4L7, Canada
| | - Emily D Cranston
- Department of Chemical Engineering, McMaster University, Hamilton, Ontario L8S 4L7, Canada; Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada; Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, BC V6T 1Z3, Canada.
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Age and Sex Normalization of Intestinal Permeability Measures for the Improved Assessment of Enteropathy in Infancy and Early Childhood: Results From the MAL-ED Study. J Pediatr Gastroenterol Nutr 2017. [PMID: 28644347 DOI: 10.1097/mpg.0000000000001610] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES The aim of the study was to describe changes in intestinal permeability in early childhood in diverse epidemiologic settings. METHODS In a birth cohort study, the lactulose:mannitol (L:M) test was administered to 1980 children at 4 time points in the first 24 months of life in 8 countries. Data from the Brazil site with an incidence of diarrhea similar to that seen in the United States and no growth faltering was used as an internal study reference to derive age- and sex-specific z scores for mannitol and lactulose recoveries and the L:M ratio. RESULTS A total of 6602 tests demonstrated mannitol recovery, lactulose recovery, and the L:M ratio were associated with country, sex, and age. There was heterogeneity in the recovery of both probes between sites with mean mannitol recovery ranging for 1.34% to 5.88%, lactulose recovery of 0.19% to 0.58%, and L:M ratios 0.10 to 0.17 in boys of 3 months of age across different sites. We observed strong sex-specific differences in both mannitol and lactulose recovery, with boys having higher recovery of both probes. Alterations in intestinal barrier function increased in most sites from 3 to 9 months of age and plateaued or diminished from 9 to 15 months of age. CONCLUSIONS Alterations in recovery of the probes differ markedly in different epidemiologic contexts in children living in the developing world. The rate of change in the L:M-z ratio was most rapid and consistently disparate from the reference standard in the period between 6 and 9 months of age, suggesting that this is a critical period of physiologic impact of enteropathy in these populations.
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Gnauck A, Lentle RG, Kruger MC. Aspirin-induced increase in intestinal paracellular permeability does not affect the levels of LPS in venous blood of healthy women. Innate Immun 2014; 21:537-45. [PMID: 25398227 DOI: 10.1177/1753425914557101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 09/29/2014] [Indexed: 11/17/2022] Open
Abstract
The presence of subclinical levels of LPS from Gram-negative bacteria, also referred to as endotoxin, in the circulation may induce a pro-inflammatory immune response that leads to the development of obesity and insulin resistance. Recent data indicate that high-fat meals may elevate circulating levels of LPS. However, it is currently unclear how the LPS transits from the gut lumen to the general circulation. We determined whether aspirin-induced damage of the small intestinal mucosa, evidenced by an increase in the paracellular permeability, allows greater transit of LPS into the systemic circulation. The 3-h cumulative excretion of lactulose was significantly increased after the consumption of aspirin solution relative to that after the consumption of an equal volume of water in 15 healthy women (median after aspirin 0.09% of dose vs. median after water 0.03% of dose; P = 0.004). Dosage with aspirin also significantly increased the lactulose : mannitol ratio (median after aspirin 0.014 vs. median after water 0.005; P = 0.017). However, serum LPS levels after the consumption of the aspirin solution were not significantly different from those after consumption of the control (plain water). Further, there was no correlation between body fat content and circulating levels of LPS.
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Affiliation(s)
- Anne Gnauck
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | - Roger G Lentle
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | - Marlena C Kruger
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
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Sequeira IR, Lentle RG, Kruger MC, Hurst RD. Differential trafficking of saccharidic probes following aspirin in clinical tests of intestinal permeability in young healthy women. Clin Exp Pharmacol Physiol 2014; 41:107-17. [DOI: 10.1111/1440-1681.12163] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 07/31/2013] [Accepted: 08/14/2013] [Indexed: 12/19/2022]
Affiliation(s)
- Ivana R Sequeira
- Institute of Food, Nutrition and Human Health; Massey University; Palmerston North New Zealand
| | - Roger G Lentle
- Institute of Food, Nutrition and Human Health; Massey University; Palmerston North New Zealand
| | - Marlena C Kruger
- Institute of Food, Nutrition and Human Health; Massey University; Palmerston North New Zealand
| | - Roger D Hurst
- The New Zealand Institute for Plant & Food Research Ltd; Palmerston North New Zealand
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Sedin J, Sjöblom M, Nylander O. The selective cyclooxygenase-2 inhibitor parecoxib markedly improves the ability of the duodenum to regulate luminal hypertonicity in anaesthetized rats. Acta Physiol (Oxf) 2012; 205:433-51. [PMID: 22251854 DOI: 10.1111/j.1748-1716.2012.02411.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 09/07/2011] [Accepted: 01/09/2012] [Indexed: 12/18/2022]
Abstract
AIM To examine whether the prevention of post-operative duodenal ileus by treatment with parecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, affects the ability of the duodenum to respond to luminal hypertonicity. METHODS The proximal duodenums of anaesthetized rats were perfused with hypertonic NaCl solutions with osmolalities of 400, 500, 600 or 700 mOsm kg(-1) , and the effects on mucosal permeability, motility, transepithelial net fluid flux and effluent osmolality were assessed in the absence (control) and presence of parecoxib. RESULTS Parecoxib-treated, but not control animals, exhibited duodenal contractions, which were reduced by the nicotinic receptor antagonists mecamylamine and hexamethonium and by perfusion with 700 mOsm kg(-1) . All animals responded to luminal hypertonicity with induction of net fluid secretion, which peaked at an osmolality of 500 mOsm kg(-1) . The hypertonicity-induced increases in fluid secretion were twofold greater in parecoxib-treated than in control rats and attenuated by nicotinic receptor blockade. The decrease in luminal osmolality correlated with the osmolality of the perfusion solution in both control and parecoxib-treated animals but the osmolality-adjusting capability was markedly better in the latter group. Rats exposed to duodenal luminal distension responded to hypertonicity with a greater fluid secretion and a larger decrease in luminal osmolality than control rats. Perfusion with 700 mOsm kg(-1) increased mucosal permeability in parecoxib-treated animals only, an effect abolished by nicotinic receptor blockade. CONCLUSION Parecoxib markedly improved the ability of the duodenum to sense and to decrease luminal hypertonicity by a mechanism most probably involving inhibition of COX-2 and stimulation of nicotinic acetylcholine receptors.
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Affiliation(s)
- J. Sedin
- Division of Physiology; Department of Neuroscience; Biomedical Center; Uppsala University; Uppsala; Sweden
| | - M. Sjöblom
- Division of Physiology; Department of Neuroscience; Biomedical Center; Uppsala University; Uppsala; Sweden
| | - O. Nylander
- Division of Physiology; Department of Neuroscience; Biomedical Center; Uppsala University; Uppsala; Sweden
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Pihl L, Wilander E, Nylander O. Comparative study of the effect of luminal hypotonicity on mucosal permeability in rat upper gastrointestinal tract. Acta Physiol (Oxf) 2008; 193:67-78. [PMID: 18005215 DOI: 10.1111/j.1748-1716.2007.01777.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
AIM To investigate whether the increase in mucosal permeability in the duodenum, induced by luminal hypotonicity, also occurs in the stomach and the jejunum and whether this increase in permeability can be explained by epithelial injury. METHODS The stomach, duodenum or jejunum of the anaesthetized rat were perfused with a hypotonic solution and effects on mucosal permeability (blood-to-lumen clearance of radioactive probes); luminal alkalinization and net fluid flux were determined in the absence and presence of cyclooxygenase inhibition. RESULTS The hypotonicity-induced (50 mM NaCl) increase in duodenal mucosal permeability was markedly larger in cyclooxygenase-2-inhibited animals than in controls and associated with a 20% decrease in luminal alkalinization and increased fluid absorption. Perfusion with 50 mM NaCl increased duodenal mucosal permeability to all probes investigated, i.e. (14)C-urea, (14)C-methyl-D-glucose, (51)Cr-EDTA and (14)C-inulin. The percentage increase in permeability was the greatest for inulin and the lowest for urea. Luminal hypotonicity caused superficial villous tip damage in some but not in all duodenal specimens but there was no difference in morphology between controls and cyclooxygenase-2-inhibited animals. Jejunum, but not the stomach, responded to luminal hypotonicity by increasing net fluid absorption, mucosal permeability (greater than sixfold) and the rate of luminal alkalinization (>100%). CONCLUSIONS The stomach does not respond while the jejunum is more sensitive to hypotonicity-induced increase in mucosal permeability than the duodenum. The hypotonicity-induced increase in duodenal mucosal permeability most probably constitutes a physiological mechanism that entails widening of paracellular pathways, which facilitates the transport of osmolytes into the lumen.
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Affiliation(s)
- L Pihl
- Department of Neuroscience, Division of Physiology, Biomedical Center, Uppsala University, Uppsala, Sweden
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Sobue M, Joh T, Oshima T, Suzuki H, Seno K, Kasugai K, Nomura T, Ohara H, Yokoyama Y, Itoh M. Contribution of capsaicin-sensitive afferent nerves to rapid recovery from ethanol-induced gastric epithelial damage in rats. J Gastroenterol Hepatol 2003; 18:1188-95. [PMID: 12974907 DOI: 10.1046/j.1440-1746.2003.03143.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND AIM It is well known that capsaicin-sensitive nerve signaling acts as a protective factor against various ulcerogens. However, the contribution of topical capsaicin-sensitive nerves within the stomach to rapid restitution has not been fully investigated. The present study was therefore conducted focusing on recovery from gastric mucosal damage induced by ethanol in vivo. METHODS Male Sprague-Dawley rats were fasted and anesthetized. 51Cr-EDTA was administered intravenously and gastric mucosal integrity was continuously monitored by measuring the blood to lumen 51Cr-EDTA clearance. Capsaicin or vehicle was irrigated before, together with or after the perfusion of 20% ethanol, followed by perfusion with saline. In another experiment, ruthenium red, a capsaicin-sensitive cation antagonist, was given before the ethanol-capsaicin perfusion. Furthermore, this study was verified using lafutidine, a histamine H2-receptor antagonist, which has a gastric mucosal protective action through the capsaicin-sensitive afferent nerves. RESULTS When capsaicin was administered before ethanol treatment, mucosal damage was significantly reduced and recovery was significantly rapid compared to the control. When capsaicin (160 micro M) and ethanol were administered simultaneously, the mucosal damage was exacerbated but recovery was nevertheless more rapid than the control group. With a lower dose of capsaicin (80 micro M), mucosal damage was not exacerbated and recovery was enhanced. When capsaicin or lafutidine was administered after the induction of ethanol injury no change was detected regarding the damage. However, recovery was significantly accelerated. Ruthenium red reversed the action of post-treatment with capsaicin on restitution. CONCLUSIONS These results indicate that luminal administration of capsaicin exerts protection against and accelerates restitution from gastric damage in the very early phase after ethanol injury. This action is probably due to activation of topical capsaicin-sensitive afferent nerves in the rat.
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Affiliation(s)
- Masashi Sobue
- First Department of Internal Medicine, Nagoya City University Medical School, Nagoya, Japan
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Nylander O, Pihl L, Perry M. Hypotonicity-induced increases in duodenal mucosal permeability facilitates adjustment of luminal osmolality. Am J Physiol Gastrointest Liver Physiol 2003; 285:G360-70. [PMID: 12686510 DOI: 10.1152/ajpgi.00428.2002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The integrated response to hypotonic NaCl solutions (100, 50, 25, and 0 mM NaCl) in proximal duodenum of anesthetized rats was examined. Luminal alkalinization, fluid flux, duodenal contractions, blood-to-lumen clearance of 51Cr-labeled EDTA (mucosal permeability), and perfusate osmolality were studied in the absence and presence of the cyclooxygenase inhibitor indomethacin. In response to hypotonic solutions net fluid absorption, increases in permeability and perfusate osmolality were markedly higher in indomethacin-treated animals than in controls, and these effects were diminished by the nicotinic-receptor antagonist hexamethonium. Infusion of iloprost, a stable PGI2 analog, to indomethacin-treated animals markedly reduced the hypotonicity-induced increase in mucosal permeability and diminished the rise in perfusate osmolality. Lowering the NaCl concentration in the perfusion solution but maintaining isotonicity with mannitol had no effect on mucosal permeability. Very good linear correlations were obtained between the degree of luminal hypotonicity and the increase in permeability and between increases in permeability and perfusate osmolality. It is concluded that luminal hypotonicity increases duodenal mucosal permeability. The hypotonicity-induced increase in permeability modulated by prostaglandins and nicotinic receptors fulfills the function of increasing blood-to-lumen transport of Na+ facilitating adjustment of luminal osmolality.
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Affiliation(s)
- Olof Nylander
- Dept. of Neuroscience, Div. of Physiology, Biomedical Center, Uppsala University, PO Box 572, S-751 23 Uppsala, Sweden.
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Nylander O, Hällgren A, Sababi M. COX inhibition excites enteric nerves that affect motility, alkaline secretion, and permeability in rat duodenum. Am J Physiol Gastrointest Liver Physiol 2001; 281:G1169-78. [PMID: 11668025 DOI: 10.1152/ajpgi.2001.281.5.g1169] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In anesthetized rats, the cyclooxygenase (COX) inhibitor indomethacin induces duodenal motility, increases duodenal mucosal alkaline secretion (DMAS), and evokes a transient increase in duodenal paracellular permeability (DPP). To examine whether enteric nerves influence these responses, the duodenum was perfused with lidocaine. Motility was assessed by measuring intraluminal pressure, and DPP was determined as blood-to-lumen clearance of (51)Cr-EDTA. DMAS was assessed by titration. In control animals, few contractions occurred during saline perfusion and lidocaine did not alter this condition. Perfusion with 0.03-0.1% lidocaine did not affect DMAS or DPP whereas 0.3-1% lidocaine reduced DMAS and increased DPP. Indomethacin induced motility and doubled DMAS. Application of 0.03% lidocaine on the duodenal serosa reduced motility and DMAS whereas 0.03% lidocaine applied luminally inhibited DMAS only. Higher concentrations of lidocaine abolished the increase in DMAS and changed the motility pattern to numerous low-amplitude contractions, the latter effect being blocked by iloprost. The lidocaine-induced increases in DPP were markedly higher than in controls. We conclude that indomethacin activates enteric nerves that induce motility, increase DMAS, and decrease DPP.
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Affiliation(s)
- O Nylander
- Department of Physiology, Uppsala University, Biomedical Center, S-751 23 Uppsala, Sweden.
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Iwata F, Joh T, Tada T, Okada N, Morgan BP, Yokoyama Y, Itoh M. Role of complement regulatory membrane proteins in ischaemia-reperfusion injury of rat gastric mucosa. J Gastroenterol Hepatol 1999; 14:967-72. [PMID: 10530491 DOI: 10.1046/j.1440-1746.1999.01985.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND The role of complement in ischaemia-reperfusion injury has not been well investigated. 5I2 is a monoclonal antibody (mAb) directed against a rat membrane inhibitor of the C3 convertase step, which is the rat counterpart of mouse Crry/p65. 6D1 is a mAb against rat CD59 which inhibits the formation of membrane attack complexes. METHODS We visualized the tissue distribution of these membrane inhibitors in rat gastrointestinal tract by immunohistochemical staining with the appropriate mAb. Then, we tested the hypothesis that complement regulatory proteins protect rat gastric mucosa against ischaemia-reperfusion stress by using these mAbs. Gastric mucosal integrity was continuously monitored by measuring the blood-to-lumen clearance of [51Cr]-labelled ethylenediaminetetraacetic acid (EDTA) under control conditions, during ischaemia and after reperfusion. RESULTS Rat 6D1 and 5I2 antigens were both widely distributed and predominantly expressed on smooth muscle and endothelial cells in gastrointestinal tracts. Blockade of complement regulatory proteins with 5I2 and 6D1 mAbs resulted in a significant increase in [51Cr]-EDTA clearance after reperfusion. CONCLUSIONS These findings support the hypothesis that endogenous complement regulatory proteins may act as important protective factors against ischaemia-reperfusion stress in rat gastric mucosa.
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Affiliation(s)
- F Iwata
- Department of Internal Medicine, West Japan NTT Tokai Hospital, Nagoya, Japan.
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Iwata F, Joh T, Ueda F, Yokoyama Y, Itoh M. Role of gap junctions in inhibiting ischemia-reperfusion injury of rat gastric mucosa. Am J Physiol Gastrointest Liver Physiol 1998; 275:G883-8. [PMID: 9815015 DOI: 10.1152/ajpgi.1998.275.5.g883] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Gap junctional intercellular communication (GJIC) is known to be important in the maintenance of tissue homeostasis. However, the role of GJIC in gastric mucosa has not been well investigated. We tested the hypothesis that maintenance of GJIC protects rat gastric mucosa against ischemia-reperfusion (I/R) stress by using irsogladine, an activator of GJIC, and octanol, an inhibitor of GJIC. Intragastric perfusion with octanol before ischemia resulted in a significant increase in 51Cr-EDTA clearance after reperfusion. Intraduodenal pretreatment with irsogladine attenuated the increase in 51Cr-EDTA clearance produced by octanol in a dose-dependent manner. Epithelial gap junctions reacted with anticonnexin-32 monoclonal antibodies were not changed after I/R stress alone. Intragastric perfusion with octanol caused a significant reduction in immunoreactive connexin-32 spots, which was completely reversed by irsogladine. These results indicate that inhibition of GJIC weakens the barrier function of gastric mucosa and subsequently causes damage of the barrier function in combination with I/R. Facilitation of GJIC and maintenance of gap junctions protect gastric mucosal barrier functions by potentiating cellular integrity.
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Affiliation(s)
- F Iwata
- Department of Internal Medicine, NTT Tokai General Hospital, Nagoya 460-0017, Japan
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Iwata F, Joh T, Yokoyama Y, Itoh M. Role of endogenous nitric oxide in ischaemia-reperfusion injury of rat gastric mucosa. J Gastroenterol Hepatol 1998; 13:997-1001. [PMID: 9835314 DOI: 10.1111/j.1440-1746.1998.tb00560.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
It has been suggested that endogenous nitric oxide may act as a protective factor for gastric mucosa since nitric oxide increases blood flow and may scavenge certain oxyradicals. We tested the hypothesis that nitric oxide protects rat gastric mucosa against ischaemia-reperfusion stress. Gastric ischaemia was induced by clamping the left gastric artery for 20 min. Rats were treated with two kinds of specific inhibitors of nitric oxide production, NG-nitro-L-arginine or NG-monomethyl-L-arginine. Gastric mucosal integrity was continuously monitored by measuring the blood-to-lumen clearance of [51chromium]-labelled ethylenediaminetetraacetic acid (EDTA) under control conditions, during ischaemia and after reperfusion. Oxidative stress in gastric mucosa was assessed by measuring dichlorofluorescein (DCF) fluorescence intensity before ischaemia and after reperfusion. Blockade of nitric oxide resulted in a significant increase in [51Cr]-EDTA clearance and DCF fluorescence intensity after reperfusion. These effects of nitric oxide inhibitors were attenuated by pretreatment with L-arginine. In conclusion, these findings support the hypothesis that endogenous nitric oxide acts as an important protective factor against ischaemia-reperfusion stress in rat gastric mucosa.
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Affiliation(s)
- F Iwata
- Department of Internal Medicine, Kosai General Hospital, Shizuoka, Japan
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Hällgren A. Duodenal mucosal permeability, bicarbonate secretion and motility. Aspects of regulation and integration of duodenal function in the rat. Minireview based on a doctoral thesis. Ups J Med Sci 1997; 102:137-73. [PMID: 9556841 DOI: 10.3109/03009739709178938] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- A Hällgren
- Department of Physiology and Medical Biophysics, Uppsala University
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Nylander O, Holm L, Wilander E, Hällgren A. Exposure of the duodenum to high concentrations of hydrochloric acid. Effects on mucosal permeability, alkaline secretion, and blood flow. Scand J Gastroenterol 1994; 29:437-44. [PMID: 8036459 DOI: 10.3109/00365529409096835] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Proximal duodenum was perfused with HCl for 5 min and the effects on blood-to-lumen clearance of 51Cr-EDTA (ED-Cl), morphology, luminal alkalinization, and blood flow determined in anesthetized rats. The rate of alkalinization was determined by back titration and blood flow assessed by laser Doppler flowmetry or by ultrasonic transit time flowmetry. Perfusion of duodenum with 30, 50 or 100 mM HCl for 5 min increased ED-Cl in a concentration-dependent manner and induced a small increase in alkalinization but had no effect on blood flow. At 55 min after cessation of perfusion with 100 mM HCl ED-Cl was 2.2-fold higher than control whereas the ED-Cl values in animals perfused with 30 or 50 mM HCl were not different from pre-acid control values. 100 mM HCl also induced an increase in 14C-mannitol and 14C-polyethylene glycol 4000 clearance, suggesting that HCl does indeed increase mucosal permeability. The 100 mM HCl-induced rise in mucosal permeability most probably reflects disturbance of mucosal integrity because three of five animals exhibited villous tip damage. The increases in ED-Cl in response to 100 mM HCl were the same in control rats as in rats with the renal pedicles ligated, indicating that the acid susceptibility is not affected by acute functional nephrectomy.
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Affiliation(s)
- O Nylander
- Dept. of Physiology and Medical Biophysics, Uppsala University, Sweden
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Ryan CM, Schmidt J, Lewandrowski K, Compton CC, Rattner DW, Warshaw AL, Tompkins RG. Gut macromolecular permeability in pancreatitis correlates with severity of disease in rats. Gastroenterology 1993; 104:890-5. [PMID: 8440440 DOI: 10.1016/0016-5085(93)91027-f] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Increased intestinal macromolecular permeability could allow absorption of substances from the bowel into the systemic circulation and contribute to multiple organ system failure. METHODS Mild, intermediate, and severe grades of pancreatitis were induced in rats using intravenous caerulein and intraductal glycodeoxycholic acid. [14C]polyethylene glycol (molecular weight, 3350 daltons; 1.1 microCi/142 mg) was instilled into the distal duodenum. At 24 hours, the animals were killed, ascitic fluid was collected for trypsinogen activation peptide measurement, and pancreatic specimens were collected and scored for based on the degree of necrosis, inflammation, and hemorrhage. RESULTS Gut permeability to polyethylene glycol 3350 (PEG 3350) was increased in animals with early experimental pancreatitis (5.4% +/- 1.2%, n = 20) when compared with control animals (1.8% +/- 0.2%; n = 6) (P = 0.0005). Furthermore, intestinal macromolecular permeability to PEG 3350 correlated with severity of disease as predicted by the method of induction of pancreatitis (P = 0.0003), the histological findings (P = 0.0002), and total ascitic trypsinogen activation peptides content (P = 0.029). CONCLUSIONS Increased gut permeability in experimental pancreatitis can be correlated with pancreatitis severity.
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Affiliation(s)
- C M Ryan
- Massachusetts General Hospital, Department of Surgery, Harvard Medical School, Boston
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Nylander O, Sababí M, Bark J. Characterization of 51Cr-EDTA as a marker of duodenal mucosal permeability. ACTA PHYSIOLOGICA SCANDINAVICA 1991; 143:117-26. [PMID: 1957698 DOI: 10.1111/j.1748-1716.1991.tb09206.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Proximal duodenum was perfused with various solutions and mucosal permeability assessed by measuring the clearance of 51Cr labelled ethylenediaminetetra-acetate (EDTA) from blood-to-intestinal lumen in anaesthetized rats. Net flux of fluid was determined by measurement of effluent weight changes. Perfusion of duodenum with 50 mM NaCl significantly increased fluid absorption but had no effect on EDTA clearance. EDTA clearance was unaffected by perfusion with 400 mM or 800 mM mannitol. Perfusion with 400 mM NaCl induced a sustained fluid secretion and a small but irregular increase (40%) in EDTA clearance. A significant 3.6-fold increase in clearance was obtained in response to perfusion of duodenum with deionized water. Similarly, perfusion with either 20 mM HCl or 50 mM ethyleneglycol-bis-(beta-amino-ethylether)-N,N'-tetraacetic acid (EGTA) significantly increased the EDTA clearance 3.3-fold and 2-fold respectively. Perfusion with a hypotonic HCl-solution (10 mM HCl + 40 mM NaCl) increased fluid absorption and the EDTA clearance. It is concluded that no positive linear relationship exists between luminal osmolality and 51Cr-EDTA movement across the mucosa. It is postulated that high luminal acidity or extreme hypotonicity increase the EDTA clearance by widening of and/or disruption of intercellular junctional structure.
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Affiliation(s)
- O Nylander
- Department of Physiology and Medical Biophysics, Uppsala University, Sweden
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Crissinger KD, Granger DN. Mucosal injury induced by ischemia and reperfusion in the piglet intestine: influences of age and feeding. Gastroenterology 1989; 97:920-6. [PMID: 2506102 DOI: 10.1016/0016-5085(89)91498-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The pathogenesis of neonatal necrotizing enterocolitis is unknown, but enteral alimentation, infectious agents, and mesenteric ischemia have been frequently invoked as primary initiators of the disease. To define the vulnerability of the intestinal mucosa to ischemia and reperfusion in the developing piglet, we evaluated changes in mucosal permeability using plasma-to-lumen clearance of chromium 51-labeled ethylenediaminetetraacetic acid in the ileum of anesthetized 1-day-, 3-day-, 2-wk-, and 1-mo-old piglets as a function of (a) duration of intestinal ischemia (20, 40, or 60 min of total superior mesenteric artery occlusion), (b) feeding status (fasted or nursed), and (c) composition of luminal perfusate (balanced salt solution vs. predigested cow milk-based formula). Baseline chromium 51-labeled ethylenediaminetetraacetic acid clearance was not significantly altered by ischemia, irrespective of duration, or feeding in all age groups. However, clearances were significantly elevated during reperfusion after 1 h of total intestinal ischemia in all age groups, whether fasted or fed. Reperfusion-induced increases in clearance did not differ among age groups when the bowel lumen was perfused with a balanced salt solution. However, luminal perfusion with formula resulted in higher clearances in 1-day-old piglets compared with all older animals. Thus, the neonatal intestine appears to be more vulnerable to mucosal injury induced by ischemia and reperfusion in the presence of formula than the intestine of older animals.
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Affiliation(s)
- K D Crissinger
- Department of Physiology and Biophysics, Louisiana State University Medical Center, Shreveport
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Affiliation(s)
- J B Fozard
- Department of Surgery, University of Leeds
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