Heat stress modulated gastrointestinal barrier dysfunction: role of tight junctions and heat shock proteins

Abstract

Increased environmental temperature exerts a visible impact on an individual's physiology. At the onset of heat stress, there is an increase in core body temperature which triggers peripheral vasodilation and sweating in an effort to dissipate the elevated body heat. The increase in peripheral circulation however reduces blood flow to the internal organs which are thus adversely affected. In particular, the gastrointestinal (GI) tract gets adversely affected during hyperthermia resulting in loosening of the tight junctions (TJs) that finally leads to higher intestinal permeability. At the cellular level, elevated levels of heat shock proteins (HSPs) induced in response to heat stress mediated cytoprotection by maintaining proper protein folding, releasing survival signals and preserving cytoskeleton integrity. Recent studies have indicated that HSPs play a crucial role in maintaining the localization of TJ proteins. Dietary supplements have also shown to have a positive effect on the maintenance of intestinal TJs. Therefore, it becomes imperative to understand the cellular, molecular and physiological alterations in response to heat stress in GI tract. In the present report, the effect of thermal stress on GI tract has been summarized. Specific role of HSPs along with mitogen activated protein (MAP) kinase signaling pathway in response to hyperthermia has also been discussed.

Yeast fermentate prebiotic improves intestinal barrier integrity during heat stress by modulation of the gut microbiota in rats

“…Exposure of rats, pretreated with PBS, to heat stress conditions resulted in significant decrease of occludin, claudin, ZO‐1 and JAM‐A expression. Decreased expression of TJ proteins during heat stress was found in Caco‐2 cells (Gupta et al, ) and in animal studies (Wu et al, ). Inhibition of these proteins expression indicates the disturbance of the TJ barrier functions and accompanied by intestinal permeability (He et al, ).…”

Milk yield, milk composition, and milk metabolomics of dairy goats intramammary-challenged with lipopolysaccharide under heat stress conditions

“…The activation of NFkB pathway increases tight junction permeability through expression changes of claudins in the mammary gland 37 . The higher losses of milk lactose detected in HS-LPS can be explained by greater tight junction leakiness, since HS has been shown to compromise tight junction integrity in other tissues such as the gastrointestinal barrier 9,38 .…”

Ginseng Extract Ameliorates the Negative Physiological Effects of Heat Stress by Supporting Heat Shock Response and Improving Intestinal Barrier Integrity: Evidence from Studies with Heat-Stressed Caco-2 Cells, C. elegans and Growing Broilers

“…The intestinal barrier is the first line of defense against harmful microbial pathogens and antigens from the intestinal lumen. Additionally, the intestinal barrier is formed by a layer of epithelial cells and sealed by tight junctions, which are mainly composed of transmembrane proteins such as claudins and occludins [8]. Tight junctions act as selective barriers that regulate paracellular transport.…”