How Does the Esophageal Epithelium Maintain Its Integrity?

Abstract

The esophageal epithelium maintains its integrity by both structural and functional epithelial defenses. Structural components are cell membranes and intercellular junctional complexes. Functional components are cellular defenses against acidification consisting of intracellular buffering by basic proteins and bicarbonate as well as epithelial transport (Na⁺/H⁺ exchange and Na⁺-dependent CI-/HCO₃ exchange). Epithelial repair is also a functional component and can be carried out by cell replication and possibly by epithelial restitution.

Intrinsic resistance triggered under acid loading within normal esophageal epithelial cells: NHE1- and ROS-mediated survival

“…Pharmacological NHE1‐dependent inhibition by cariporide or EIPA (Masereel et al, ) further reduced AM4‐induced cell viability. NHE1 is present on the membrane of esophageal epithelial cell and regulate intracellular pH under external acidosis (Tobey, ; Lao‐Sirieix et al, ). When cells are exposed to low external pH, H + loading occurs.…”

“…The epithelial layer of the esophageal mucosa is a structural and functional barrier on the luminal side. It defends the esophageal mucosa by maintaining mucosal integrity with the tight junction, and by enabling repair after damage through restitution, proliferation, and ion transporter and intracellular or extracellular buffers, such as proteins (Goldstein et al, ; Tobey, ; Fitzgerald et al, ; Orlando, ; Squier and Kremer, ; Okuyama et al, ). Including esophageal epithelium, intrinsic cellular defenses mediated by various signal molecules are activated in a variety of cells under stress.…”

Estudo comparativo da concentração salivar do fator de crescimento epidérmico em indivíduos com laringite crônica por doença do refluxo gastroesofágica antes e após o tratamento: resultados preliminares

“…Certainly, the gastric and esophageal mucosal protection mechanisms have a decisive role in the capacity these organs have of withstanding mechanical and chemical aggression to which they are daily exposed, and many of these mechanisms are saliva-mediated 15,[20][21][22][23][24][25][26][27] . Saliva has many organic and inorganic substances that contribute to this protection against physical and chemical attacks, and used for the maintenance of the mucosal lining, not only of the oral mucosa, but also that of the digestive tract20-26.…”

“…Saliva has many organic and inorganic substances that contribute to this protection against physical and chemical attacks, and used for the maintenance of the mucosal lining, not only of the oral mucosa, but also that of the digestive tract20-26. Contradictory clinical findings and recent research reports suggest deficiencies in the defense capacity of this segment in GERD [22][23][24] patients and, more specifically, in LPR 15,[27][28][29] . One of the factors most responsible for homeostasis of the oral mucosa and the digestive tract is the saliva and its organic content.…”

Morphology and Glycoconjugate Content of Opossum Esophageal Epithelium and Glands: Regional Heterogeneity and Effects of Acid-Induced Mucosal Injury and Recovery

“…As such, prevention of acid entry by the stratified squamous epithelium is a critical defense against mucosal damage (8). In the rabbit, transcellular movement of luminal H + into epithelial cells is prevented by a highly impermeable apical membrane able to withstand proton gradients of 100,000:1.…”