Effect of heat stress on rabbit esophageal epithelium

Abstract

Hot beverages expose the esophageal epithelium to temperatures as high as 58°C. To study the impact of such temperatures, rabbit esophageal epithelium was exposed to luminal heat or both luminal and serosal heat while mounted in Ussing chambers. Luminal heat, mimicking exposure to hot beverages, reduced potential difference (PD) and resistance ( R) when applied at ≥49°C and reduced short-circuit current ( I sc) at ≥60°C. At ≥60°C, subepithelial blisters developed. Higher temperatures reduced R only moderately and reversibly. In contrast, the I sc declined sharply and irreversibly once threshold was reached. Luminal and serosal heat also reduced PD, I sc, and R, although the threshold for reduction in I scwas now similar to that for R. Additionally, luminal and serosal heat reduced I sc more than R for any given temperature and resulted in blisters at lower temperatures (50°C) than luminal heat alone. The heat-induced decline in I sc was attributed in part to inactivation of Na-K-ATPase activity, although other transport systems could have been equally affected, and the decline in R to an increase in paracellular permeability. The latter effect on R also contributed to an increase in tissue sensitivity to luminal acid damage. Consumption of hot beverages exposes the esophagus to temperatures that can negatively impact epithelial structure and function. Impaired barrier function by heat increases the risk of esophageal damage by subsequent contact with (refluxed) gastric acid. These findings help explain in part the association between esophageal disease and consumption of hot beverages.

Tea drinking habits and oesophageal cancer in a high risk area in northern Iran: population based case-control study

“…Once the threshold temperature is reached, the barrier function could be impaired rapidly and with short exposure times. 30 Whatever the mechanism by which thermal injury increases the risk of oesophageal cancer, this risk can be augmented by other risk factors, such as low intake of fresh fruits and vegetables, which can impair DNA repair. 33 Both green and black teas have shown cancer prevention activity in animal models, which may be attributable to flavonoids and other beneficial compounds [34][35][36] ; however, such activity has not been convincingly shown in humans.…”

Nonselective cation transport in native esophageal epithelia

“…6 were also carried out in the presence of 1 mM ouabain to eliminate any residual contribution of the basolateral Na ϩ -K ϩ -ATPase to transepithelial transport. This concentration of ouabain is known to inhibit this enzyme in rabbit esophageal epithelia (40), and its lack of action provides further evidence supporting the electrical elimination of the basolateral membrane.…”

“…These findings led us to examine the properties of the native apical channel in more detail, taking advantage of the ability to permeabilize the basolateral membrane. We report that the previously postulated Na ϩ -selective apical channel (5,18,39,40) is, in fact, nonselective for monovalent cations (Na ϩ , Li ϩ , and K ϩ ) and is also amiloride insensitive. Despite the presence of ␣-, ␤-, and ␥-ENaC, this native channel did not exhibit any of the properties of the classic Na ϩ channel.…”

Oesophageal heat exchangers with a diameter of 11mm or 14.7mm are equally effective and safe for targeted temperature management

“…Given a thermal dosage of 45°C x 30min [33] able to induce epithelial oesophageal damage [20, 34], an intraoesophageal upper temperature threshold of 41°C, which was the maximum temperature applied to the oesophagus by the OHE in the present study, seemed to be safe in minimizing the incidence of thermal oesophageal tissue damage [35]. Presumably, therefore, tissue damage was absent in cranial, middle and caudal oesphageal tissue segments.…”