1
|
Abdulnour-Nakhoul SM, Nakhoul NL. Ussing Chamber Methods to Study the Esophageal Epithelial Barrier. Methods Mol Biol 2021; 2367:215-233. [PMID: 32946026 DOI: 10.1007/7651_2020_324] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The Ussing chamber was developed in 1949 by Hans Ussing and quickly became a powerful tool to study ion and solute transport in epithelia. The chamber has two compartments strictly separating the apical and basolateral sides of the tissue under study. The two sides of the tissue are connected via electrodes to a modified electrometer/pulse generator that allows measurement of electrical parameters, namely, transepithelial voltage, current, and resistance. Simultaneously, permeability of the tissue to specific solutes or markers can be monitored by using tracers or isotopes to measure transport from one side of the tissue to the other. In this chapter, we will describe the use of the Ussing chamber to study the barrier properties of the mouse esophageal epithelium. We will also briefly describe the use of the modified Ussing chamber to simultaneously study transepithelial and cellular electrophysiology in the rabbit esophageal epithelium. Lastly, we will cover the use of the Ussing chamber to study bicarbonate secretion in the pig esophagus. These examples highlight the versatility of the Ussing chamber technique in investigating the physiology and pathophysiology of epithelia including human biopsies.
Collapse
Affiliation(s)
| | - Nazih L Nakhoul
- Departments of Medicine and Physiology, Tulane University School of Medicine, New Orleans, LA, USA
| |
Collapse
|
2
|
Andrini LB, García MN, Inda AM, Errecalde AL, Goin FJ, Carlini AA, Scarano AC, Martin G, de los Reyes M. Comparative histology of the digestive tract in three new world marsupials. ACTA ZOOL-STOCKHOLM 2018. [DOI: 10.1111/azo.12241] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Laura Beatríz Andrini
- Facultad de Ciencias Médicas; Cátedra de Citología y Embriología A; Universidad Nacional de La Plata; La Plata Argentina
| | - Marcela Nilda García
- Facultad de Ciencias Médicas; Cátedra de Citología y Embriología A; Universidad Nacional de La Plata; La Plata Argentina
| | - Ana María Inda
- Facultad de Ciencias Médicas; Cátedra de Citología y Embriología A; Universidad Nacional de La Plata; La Plata Argentina
| | - Ana Lía Errecalde
- Facultad de Ciencias Médicas; Cátedra de Citología y Embriología A; Universidad Nacional de La Plata; La Plata Argentina
| | - Francisco J Goin
- CONICET; Consejo Nacional de Investigaciones Científicas y Técnicas; La Plata Argentina
- División Paleontología Vertebrados; Facultad de Ciencias Naturales y Museo; Universidad Nacional de La Plata; La Plata Argentina
| | - Alfredo Armando Carlini
- CONICET; Consejo Nacional de Investigaciones Científicas y Técnicas; La Plata Argentina
- División Paleontología Vertebrados; Facultad de Ciencias Naturales y Museo; Universidad Nacional de La Plata; La Plata Argentina
| | - Alejo Carlos Scarano
- CONICET; Consejo Nacional de Investigaciones Científicas y Técnicas; La Plata Argentina
- División Paleontología Vertebrados; Facultad de Ciencias Naturales y Museo; Universidad Nacional de La Plata; La Plata Argentina
| | - Gabriel Martin
- CONICET; Consejo Nacional de Investigaciones Científicas y Técnicas; La Plata Argentina
- Centro de Investigación Esquel de Montaña y Estepa Patagónica (CIEMEP; CONICET-UNPSJB), Esquel; Provincia del Chubut Argentina
| | - Martín de los Reyes
- División Paleontología Vertebrados; Facultad de Ciencias Naturales y Museo; Universidad Nacional de La Plata; La Plata Argentina
| |
Collapse
|
3
|
Woodley FW, Moore-Clingenpeel M, Machado RS, Nemastil CJ, Jadcherla SR, Hayes D, Kopp BT, Kaul A, Di Lorenzo C, Mousa H. Not All Children with Cystic Fibrosis Have Abnormal Esophageal Neutralization during Chemical Clearance of Acid Reflux. Pediatr Gastroenterol Hepatol Nutr 2017; 20:153-159. [PMID: 29026731 PMCID: PMC5636931 DOI: 10.5223/pghn.2017.20.3.153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/12/2017] [Accepted: 07/15/2017] [Indexed: 01/25/2023] Open
Abstract
PURPOSE Acid neutralization during chemical clearance is significantly prolonged in children with cystic fibrosis, compared to symptomatic children without cystic fibrosis. The absence of available reference values impeded identification of abnormal findings within individual patients with and without cystic fibrosis. The present study aimed to test the hypothesis that significantly more children with cystic fibrosis have acid neutralization durations during chemical clearance that fall outside the physiological range. METHODS Published reference value for acid neutralization duration during chemical clearance (determined using combined impedance/pH monitoring) was used to assess esophageal acid neutralization efficiency during chemical clearance in 16 children with cystic fibrosis (3 to <18 years) and 16 age-matched children without cystic fibrosis. RESULTS Duration of acid neutralization during chemical clearance exceeded the upper end of the physiological range in 9 of 16 (56.3%) children with and in 3 of 16 (18.8%) children without cystic fibrosis (p=0.0412). The likelihood ratio for duration indicated that children with cystic fibrosis are 2.1-times more likely to have abnormal acid neutralization during chemical clearance, and children with abnormal acid neutralization during chemical clearance are 1.5-times more likely to have cystic fibrosis. CONCLUSION Significantly more (but not all) children with cystic fibrosis have abnormally prolonged esophageal clearance of acid. Children with cystic fibrosis are more likely to have abnormal acid neutralization during chemical clearance. Additional studies involving larger sample sizes are needed to address the importance of genotype, esophageal motility, composition and volume of saliva, and gastric acidity on acid neutralization efficiency in cystic fibrosis children.
Collapse
Affiliation(s)
- Frederick W Woodley
- Division of Gastroenterology, Hepatology and Nutrition, Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | | | | | | | - Sudarshan R Jadcherla
- Division of Gastroenterology, Hepatology and Nutrition, Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,Research Institute and Neonatology, Nationwide Children's Hospital, Columbus, OH, USA
| | - Don Hayes
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,Division of Pulmonary Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Benjamin T Kopp
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,Division of Pulmonary Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Ajay Kaul
- Division of Gastroenterology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Department of Pediatrics, OSU University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Carlo Di Lorenzo
- Division of Gastroenterology, Hepatology and Nutrition, Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Hayat Mousa
- Division of Gastroenterology, Hepatology and Nutrition, Nationwide Children's Hospital, Columbus, OH, USA.,Division of Gastroenterology, Rady Children's Hospital, San Diego, CA, USA.,Department of Pediatrics, The University of California at San Diego College of Medicine, San Diego, CA, USA
| |
Collapse
|
4
|
Capanoglu D, Coskunsever D, Olukman M, Ülker S, Bor S. Esophageal Epithelial Resistance and Lower Esophageal Sphincter Muscle Contraction Increase in a Chronic Diabetic Rabbit Model. Dig Dis Sci 2016; 61:1879-87. [PMID: 26972084 DOI: 10.1007/s10620-016-4111-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 03/03/2016] [Indexed: 01/10/2023]
Abstract
BACKGROUND Esophageal motility disorders and possibly gastroesophageal reflux disease are common in patients with diabetes mellitus. AIMS We aimed to investigate both the electrophysiological characteristics of the esophageal epithelium and the contractility of the lower esophageal sphincter (LES) muscle in alloxane-induced diabetic rabbits. METHODS Electrophysiological properties were measured using an Ussing chamber method. An acid-pepsin model was employed with pH 1.7 or weakly acidic (pH 4) Ringer and/or pepsin. Smooth muscle strips of the LES were mounted in an isolated organ bath. Contractile responses to an electrical field stimulation and cumulative concentrations of acetylcholine were recorded. Contractility of the muscle strips were tested in the presence of Rho-kinase inhibitor (Y-27632) and nonspecific nitric oxide inhibitor (L-NAME). RESULTS The resistance of diabetic tissue perfused in the pH 1.7 Ringer decreased 17 %; pepsin addition decreased it by 49 %. The same concentrations caused a more distinct loss of resistance in the control tissues (22 and 76 %, p < 0.05). The perfusion of tissues in increased concentrations of luminal and serosal glucose did not change the tissue resistance and voltage. Diabetes significantly increased both the electrical field stimulation and acetylcholine-induced contractions in the LES muscle strips (p < 0.01). Incubation with Y-27632 significantly decreased the acetylcholine-induced contractions in a concentration-dependent manner (p < 0.01). CONCLUSIONS The acid-pepsin model in the diabetic rabbit esophageal tissue had less injury compared with the control. The diabetic rabbit LES muscle had higher contractility, possibly because of the activation of the Rho-Rhokinase pathway. Our results show that in a chronic diabetic rabbit model the esophagus resists reflux by activating mechanisms of mucosal defense and increasing the contractility of the LES.
Collapse
Affiliation(s)
- Doga Capanoglu
- Ege Reflux Group, Section of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, Ege University, Bornova, 35100, Izmir, Turkey
| | - Deniz Coskunsever
- Department of Medical Pharmacology, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Murat Olukman
- Department of Medical Pharmacology, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Sibel Ülker
- Department of Medical Pharmacology, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Serhat Bor
- Ege Reflux Group, Section of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, Ege University, Bornova, 35100, Izmir, Turkey.
| |
Collapse
|
5
|
Abstract
BACKGROUND AND AIM We reported that chemical clearance (CC) of acid gastroesophageal reflux (AGER) is relatively prolonged in children with cystic fibrosis (CF). Disparity in CC values within our CF cohort sparked curiosity as to what CC looks like in infants and children with AGER in the physiologic range. The aim of the study was to assess CC in infants and children with normal AGER. METHODS Impedance-pH tracings from our database for infants (≤ 12 months) and children (>12 months-18 years) were manually scanned for 2-phase AGER episodes. Tracings were excluded for patients who had AGER Indices >3% (children) or >6% (infants), had positive GER-symptom associations, were on antireflux medications, had a fundoplication, or had impedance studies shorter than 18 hour. In addition to medians (25%-75% interquartile range), we calculated the 95th percentile for the CC duration and the fifth percentile for the CC rate. RESULTS Two-phase AGER episodes were detected in 44 infants and 60 children. The median CC duration was 64.3 seconds (51.0-91.6 seconds) for infants and 37.5 seconds (27.7-52.4 seconds) for children. The median CC rate was 0.0622 pH units/second (PU/second) (0.0354-0.0946 PU/second) for infants and 0.0928 PU/second (0.0631-0.2057 PU/second) for children. The CC duration at the 95th percentile was 148.5 seconds for infants and 114.4 seconds for children. The CC rate at the fifth percentile was 0.0088 PU/second for infants and 0.0465 PU/second for children. CONCLUSIONS We report reference values for CC in infants and children who have normal acid reflux. These values should not be used as "cutoff values" because they were derived from infant and children cohorts that did not include individuals with intermediate AGER.
Collapse
|
6
|
Durkes A, Sivasankar MP. Bicarbonate availability for vocal fold epithelial defense to acidic challenge. Ann Otol Rhinol Laryngol 2014; 123:71-6. [PMID: 24574427 DOI: 10.1177/0003489414521143] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Bicarbonate is critical for acid-base tissue homeostasis. In this study we investigated the role of bicarbonate ion transport in vocal fold epithelial defense to acid challenges. Acidic insults to the larynx are common in gastric reflux, carcinogenesis and metastasis, and acute inflammation. METHODS Ion transport was measured in viable porcine vocal fold epithelium. First, 18 vocal folds were exposed to either the carbonic anhydrase antagonist acetazolamide or to vehicle. Second, 32 vocal folds were exposed to either a control buffer or a bicarbonate-free buffer on their luminal or basolateral surface or both. Third, 32 vocal folds were challenged with acid in the presence of bicarbonate-free or control buffer. RESULTS The vocal fold transepithelial resistance was greater than 300 Ω*cm(2), suggesting robust barrier integrity. Ion transport did not change after exposure to acetazolamide (p > 0.05). Exposure to bicarbonate-free buffer did not compromise vocal fold ion transport (p > 0.05). Ion transport increased after acid challenge. This increase approached statistical significance and was the greatest for the control buffer and for the bicarbonate-free buffer applied to the basolateral surface. CONCLUSIONS Bicarbonate secretion may contribute to vocal fold defense against acid challenge. Our data offer a potential novel role for bicarbonate as a therapeutic agent to reduce pH abnormalities in the larynx and prevent associated pathological changes.
Collapse
Affiliation(s)
- Abigail Durkes
- Department of Comparative Pathobiology, College of Veterinary Medicine (Durkes), Purdue University, West Lafayette, Indiana
| | | |
Collapse
|
7
|
Woodley FW, Machado RS, Hayes D, Di Lorenzo C, Kaul A, Skaggs B, McCoy K, Patel A, Mousa H. Children with cystic fibrosis have prolonged chemical clearance of acid reflux compared to symptomatic children without cystic fibrosis. Dig Dis Sci 2014; 59:623-30. [PMID: 24287640 DOI: 10.1007/s10620-013-2950-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/11/2013] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Few studies compare gastroesophageal reflux (GER) parameters of cystic fibrosis (CF) children and symptomatic non-CF children. We aimed to compare the impedance-pH (IMP-pH) parameters for these two groups and to test the hypothesis that prolonged acid exposure in CF patients is due to delayed chemical clearance (CC). METHODS IMP-pH tracings from 16 CF children (median 8.2 years) and 16 symptomatic non-CF children (median 8.3 years) were analyzed. Software was used to generate IMP-pH reports and parameter data were extracted. IMP-pH was used to calculate the mean CC for each patient. RESULTS pH studies showed no difference in acid GER (AGER) frequency (p = 0.587); however, mean AGER duration, duration of longest AGER, AGER index, and DeMeester scores were all significantly higher for CF patients. IMP showed no difference in GER frequency [neither acidic (p = 0.918) nor non-acidic (p = 0.277)], but total bolus clearance was more efficient in CF patients (p = 0.049). A larger percentage of total GER reached the proximal esophagus in non-CF children (p = 0.039). Analyses of two-phase AGER episodes showed that these events were more acidic (p = 0.003) and the CC phase was significantly prolonged in the CF cohort (p = 0.001). CONCLUSIONS Compared to symptomatic non-CF children, CF children do not have more frequent reflux. Actually, they have better bolus clearance efficiency following reflux and may even have better control over the number of GER episodes that reach the proximal esophagus. CC of AGER, however, is significantly prolonged in the CF cohort, likely due to hyperacidity of refluxed gastric contents.
Collapse
Affiliation(s)
- Frederick W Woodley
- Division of Gastroenterology, Hepatology, and Nutrition, Nationwide Children's Hospital, Columbus, OH, USA,
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Garman KS, Orlando RC, Chen X. Review: Experimental models for Barrett's esophagus and esophageal adenocarcinoma. Am J Physiol Gastrointest Liver Physiol 2012; 302:G1231-43. [PMID: 22421618 PMCID: PMC4380479 DOI: 10.1152/ajpgi.00509.2011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Several different cell culture systems and laboratory animal models have been used over the years to study Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). Most of the existing models have key differences with the human esophagus and complex pathogenesis of disease. None of the models offers an ideal system for the complex study of environmental exposure, genetic risk, and prevention strategies. In fact, different model systems may be required to answer different specific research questions about the pathogenesis of BE and EAC. Given the high mortality associated with EAC and the fact that current screening strategies miss most cases of EAC, advances in basic and translational science related to esophageal injury, repair, and carcinogenesis are clearly needed. This review describes several of the existing and potential model systems for BE and EAC with their benefits and disadvantages.
Collapse
Affiliation(s)
- Katherine S. Garman
- 1Division of Gastroenterology, Department of Medicine, Duke University and Durham Veterans Affairs Medical Center, Durham;
| | - Roy C. Orlando
- 2Division of Gastroenterology and Hepatology, Center for Esophageal Diseases and Swallowing, University of North Carolina at Chapel Hill, Chapel Hill; and
| | - Xiaoxin Chen
- 3Cancer Research Program, Julius L. Chambers Biomedical Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina
| |
Collapse
|
9
|
Abdulnour-Nakhoul S, Nakhoul HN, Kalliny MI, Gyftopoulos A, Rabon E, Doetjes R, Brown K, Nakhoul NL. Ion transport mechanisms linked to bicarbonate secretion in the esophageal submucosal glands. Am J Physiol Regul Integr Comp Physiol 2011; 301:R83-96. [PMID: 21474426 DOI: 10.1152/ajpregu.00648.2010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The esophageal submucosal glands (SMG) secrete HCO(3)(-) and mucus into the esophageal lumen, where they contribute to acid clearance and epithelial protection. This study characterized the ion transport mechanisms linked to HCO(3)(-) secretion in SMG. We localized ion transporters using immunofluorescence, and we examined their expression by RT-PCR and in situ hybridization. We measured HCO(3)(-) secretion by using pH stat and the isolated perfused esophagus. Using double labeling with Na(+)-K(+)-ATPase as a marker, we localized Na(+)-coupled bicarbonate transporter (NBCe1) and Cl(-)-HCO(3)(-) exchanger (SLC4A2/AE2) to the basolateral membrane of duct cells. Expression of cystic fibrosis transmembrane regulator channel (CFTR) was confirmed by immunofluorescence, RT-PCR, and in situ hybridization. We identified anion exchanger SLC26A6 at the ducts' luminal membrane and Na(+)-K(+)-2Cl(-) (NKCC1) at the basolateral membrane of mucous and duct cells. pH stat experiments showed that elevations in cAMP induced by forskolin or IBMX increased HCO(3)(-) secretion. Genistein, an activator of CFTR, which does not increase intracellular cAMP, also stimulated HCO(3)(-) secretion, whereas glibenclamide, a Cl(-) channel blocker, and bumetanide, a Na(+)-K(+)-2Cl(-) blocker, decreased it. CFTR(inh)-172, a specific CFTR channel blocker, inhibited basal HCO(3)(-) secretion as well as stimulation of HCO(3)(-) secretion by IBMX. This is the first report on the presence of CFTR channels in the esophagus. The role of CFTR in manifestations of esophageal disease in cystic fibrosis patients remains to be determined.
Collapse
Affiliation(s)
- Solange Abdulnour-Nakhoul
- Southeast Louisiana Veterans Health Care Network, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA.
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Abdulnour-Nakhoul S, Tobey NA, Nakhoul NL, Wheeler SA, Vanegas X, Orlando RC. The effect of tegaserod on esophageal submucosal glands bicarbonate and mucin secretion. Dig Dis Sci 2008; 53:2366-72. [PMID: 18270837 DOI: 10.1007/s10620-007-0170-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Accepted: 12/04/2007] [Indexed: 12/09/2022]
Abstract
Tegaserod, a 5-HT4 partial agonist, was shown to reduce esophageal acid exposure in patients with gastroesophageal reflux disease; however, its mechanism of action is poorly understood. Therefore, we have examined the effect of tegaserod on luminal bicarbonate and mucin secretion in the isolated perfused pig esophagus. We also studied its role in esophageal protection using SMG-bearing pig esophagus in comparison to the rabbit esophagus, which is devoid of them. The tissues were mounted in Ussing chambers, and acid injury was replicated by exposing the lumen to acid (pH 1.6) or acid/pepsin (pH 2.5). In pig esophagus, tegaserod increased bicarbonate secretion, but had no effect on basal mucin secretion. In Ussing chambers, tegaserod reduced injury to pig, but not rabbit esophagus exposed to acid (pH 2.5) plus pepsin. These results indicate that tegaserod stimulates SMG bicarbonate secretion, an effect that likely accounts for the observed protection against acid-pepsin injury to pig, but not rabbit, esophagus.
Collapse
Affiliation(s)
- Solange Abdulnour-Nakhoul
- Southeast Louisiana Veterans Health Care Network, and Departments of Medicine and Physiology, Tulane University School of Medicine, c/o Tulane Medical Center, 1430 Tulane Avenue, New Orleans, LA 70112-2699, USA.
| | | | | | | | | | | |
Collapse
|
11
|
Abdulnour-Nakhoul S, Nakhoul NL, Wheeler SA, Haque S, Wang P, Brown K, Orlando G, Orlando RC. Characterization of esophageal submucosal glands in pig tissue and cultures. Dig Dis Sci 2007; 52:3054-65. [PMID: 17394068 DOI: 10.1007/s10620-006-9739-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Accepted: 12/15/2006] [Indexed: 12/09/2022]
Abstract
The submucosal glands (SMGs) of the pig esophagus, like the human, secrete mucin and bicarbonate, which help in luminal acid clearance and epithelial protection. The aim of this study was to characterize histochemically the esophageal SMGs and a primary culture obtained from these glands. Tissues and cultures were stained with hematoxylin and eosin, periodic acid Schiff, Alcian blue, lectins, or cytokeratins. In the perfused esophagus, addition of carbachol increased mucin secretion by approximately 2-fold. The results indicate that [1] a method for culturing SMG cells was developed; [2] conventional staining indicates the presence of sulfated, acidic, and neutral mucopolysaccharides in glands and cultures; [3] lectin binding indicates the presence of N-acetyl glucosamine, N-acetyl neuraminic acid, N-acetyl galactosamine, and alpha-L: -fucose in mucous cells and cultures; [4] cytokeratin and lectin staining indicated similarities with Barrett epithelium (columnar metaplasia of the esophagus); and [5] cholinergic agonists enhance mucin secretion and this could play a significant role in esophageal protection.
Collapse
Affiliation(s)
- Solange Abdulnour-Nakhoul
- Department of Medicine, SL 45, 1430 Tulane Avenue, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA.
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Tobey NA, Argote CM, Awayda MS, Vanegas XC, Orlando RC. Effect of luminal acidity on the apical cation channel in rabbit esophageal epithelium. Am J Physiol Gastrointest Liver Physiol 2007; 292:G796-805. [PMID: 16614374 DOI: 10.1152/ajpgi.00385.2005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Esophageal epithelial cells contain an apical cation channel that actively absorbs sodium ions (Na(+)). Since these channels are exposed in vivo to acid reflux, we sought the impact of high acidity on Na(+) channel function in Ussing-chambered rabbit epithelium. Serosal nystatin abolished short-circuit current (I(sc)) and luminal pH titrated from pH 7.0 to pH > or = 2.0 had no effect on I(sc). Circuit analysis at pH 2.0 showed small, but significant, increases in apical and shunt resistances. At pH < 2.0, I(sc) increased whereas resistance (R(T)) decreased along with an increase in fluorescein flux. The change in I(sc), but not R(T), was reversible at pH 7.4. Reducing pH from 7.0 to 1.1 with H(2)SO(4) gave a similar pattern but higher I(sc) values, suggesting shunt permselectivity. A 10:1 Na(+) gradient after nystatin increased I(sc) by approximately 4 muAmps/cm(2) and this declined at pH < or = 3.5 until it reached approximately 0.0 at pH 2.0. Impedance analysis on acid-exposed (non-nystatin treated) tissues showed compensatory changes in apical (increase) and basolateral (decrease) resistance at modest luminal acidity that were poorly reversible at pH 2.0 and associated with declines in capacitance, a reflection of lower apical membrane area. In esophageal epithelium apical cation channels transport Na(+) at gradients as low as 10:1 but do not transport H(+) at gradients of 100,000:1 (luminal pH 2.0). Luminal acid also inhibits Na(+) transport via the channels and abolishes it at pH 2.0. These effects on the channel may serve as a protective function for esophageal epithelium exposed to acid reflux.
Collapse
Affiliation(s)
- N A Tobey
- Department of Medicine, Tulane University Health Sciences Center and the Veterans Administration Hospital, New Orleans, Louisiana 70112, USA.
| | | | | | | | | |
Collapse
|
13
|
White RJ, Morris GP, Cooke K, Paterson WG. Morphology and glycoconjugate content of opossum esophageal epithelium and glands: regional heterogeneity and effects of acid-induced mucosal injury and recovery. Dig Dis Sci 2005; 50:1591-604. [PMID: 16133956 DOI: 10.1007/s10620-005-2902-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2004] [Accepted: 11/16/2004] [Indexed: 12/16/2022]
Abstract
This study examined the regional heterogeneity and site-specific changes in histology and glycoconjugate content following the induction of esophagitis and after recovery in an established animal model. Esophageal samples were excised from five sites in anesthetized opossums 24 hr after 3 consecutive days of 45-min perfusion with saline or 100 mM HCl or 1 week after acid in recovery animals. Controls exhibited significant regional differences in epithelial thickness, gland volume, glycoconjugate composition, and mast cell numbers. Acid perfusion induced erosive esophagitis and significant epithelial denudation throughout the distal 7 cm, combined with significant site-specific increases in gland lumen volume, decreases in mast cell numbers, and changes in glycoconjugate content. No differences from controls were noted in recovery animals, except for a significant increase in epithelial thickness and change in glycoconjugate content in the distal 2 cm. The results of this study highlight the impact of acid exposure on these structural defenses, but further investigation is required to explore the importance of these acid-induced changes in the pathogenesis of reflux esophagitis.
Collapse
Affiliation(s)
- Robert J White
- Gastrointestinal Diseases Research Unit and Department of Biology, Queen's University, Kingston, Ontario, Canada
| | | | | | | |
Collapse
|
14
|
Abdulnour-Nakhoul S, Nakhoul NL, Wheeler SA, Wang P, Swenson ER, Orlando RC. HCO3- secretion in the esophageal submucosal glands. Am J Physiol Gastrointest Liver Physiol 2005; 288:G736-44. [PMID: 15576627 DOI: 10.1152/ajpgi.00055.2004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The mammalian esophagus has the capacity to secrete a HCO(3)(-) and mucin-rich fluid in the esophageal lumen. These secretions originate from the submucosal glands (SMG) and can contribute to esophageal protection against refluxed gastric acid. The cellular mechanisms by which glandular cells achieve these secretions are largely unknown. To study this phenomenon, we used the pH-stat technique to measure luminal alkali secretion in an isolated, perfused pig esophagus preparation. Immunohistochemistry was used to localize receptors and transporters involved in HCO(3)(-) transport. The SMG-bearing esophagus was found to have significant basal alkali secretion, predominantly HCO(3)(-), which averaged 0.21 +/- 0.04 microeq.h(-1).cm(-2). This basal secretion was doubled when stimulated by carbachol but abolished by HCO(3)(-) or Cl(-) removal. Basal- and carbachol-stimulated secretions were also blocked by serosal application of atropine, pirenzipine, DIDS, methazolamide, and ethoxzolamide. The membrane-impermeable carbonic anhydrase inhibitor benzolamide, applied to the serosal bath, partially inhibited basal HCO(3)(-) secretion and blocked the stimulation by carbachol. Immunohistochemistry using antibodies to M(1) cholinergic receptor or carbonic anhydrase-II enzyme showed intense labeling of duct cells and serous demilunes but no labeling of mucous cells. Labeling with an antibody to Na(+)-(HCO(3)(-))(n) (rat kidney NBC) was positive in ducts and serous cells, whereas labeling for Cl(-)/HCO(3)(-) exchanger (AE2) was positive in duct cells but less pronounced in serous cells. These data indicate that duct cells and serous demilunes of SMG play a role in HCO(3)(-) secretion, a process that involves M(1) cholinergic receptor stimulation. HCO(3)(-) transport in these cells is dependent on cytosolic and serosal membrane-bound carbonic anhydrase. HCO(3)(-) secretion is also dependent on serosal Cl(-) and is mediated by DIDS-sensitive transporters, possibly NBC and AE2.
Collapse
Affiliation(s)
- Solange Abdulnour-Nakhoul
- The VA Medical Center, Attn: Research, Rm. 5F151, 1601 Perdido St., New Orleans, LA 70112-2699, USA.
| | | | | | | | | | | |
Collapse
|