The effects of acute oral glutamine supplementation on exercise-induced gastrointestinal permeability and heat shock protein expression in peripheral blood mononuclear cells

Abstract

Chronic glutamine supplementation reduces exercise-induced intestinal permeability and inhibits the NF-κB pro-inflammatory pathway in human peripheral blood mononuclear cells. These effects were correlated with activation of HSP70. The purpose of this paper is to test if an acute dose of oral glutamine prior to exercise reduces intestinal permeability along with activation of the heat shock response leading to inhibition of pro-inflammatory markers. Physically active subjects (N=7) completed baseline and exercise intestinal permeability tests, determined by the percent ratio of urinary lactulose (5 g) to rhamnose (2 g). Exercise included two 60-min treadmill runs at 70 % of VO 2 max at 30°C after ingestion of glutamine (Gln) or placebo (Pla). Plasma levels of endotoxin and TNF-α, along with peripheral blood mononuclear cell (PBMC) protein expression of HSP70 and IκBα, were measured pre-and post-exercise and 2 and 4 h postexercise. Permeability increased in the Pla trial compared to that at rest (0.06±0.01 vs. 0.02±0.018) and did not increase in the Gln trial. Plasma endotoxin was lower at the 4-h time point in the Gln vs. 4 h in the Pla (6.715±0.046 pg/ml vs. 7.952±

Oral Glutamine Supplement Reduces Subjective Fatigue Ratings during Repeated Bouts of Firefighting Simulations

“…We previously supplemented glutamine at dosages ranging from 0.90 to 0.075 g/kg/day. The decision to dose at 0.15 g/kg/day was to balance between preventing adverse responses (e.g., gastrointestinal complaints, headaches) to high supplementation while providing an effective amount [20,21,29,37].…”

Systematic review: exercise‐induced gastrointestinal syndrome—implications for health and intestinal disease

“…L‐citrulline and L‐arginine are precursors for nitric oxide production, which is a potent vasodilator, potentially enhancing blood flow into the intestinal microvasculature reducing exercise‐induced hypoperfusion and ischaemic . Glutamine and bovine colostrum have been proposed to enhance the expression of heat shock proteins (ie, proteins that protect cellular membrane under period of stress), which may protect the intestinal enterocytes, reduce intestinal permeability, and attenuate the development of local inflammatory pathways . However, due to heterogeneity methods across studies (ie, magnitude of exercise‐ and heat‐stress, population, supplementation period and dose) and discrepancy in outcomes, the evidence for the use of singular dietary supplements in the prevention and management of exercise‐induced gastrointestinal syndrome in human populations is not clear, and warrants further investigation.…”

Physiological regulation of the heat shock response by glutamine: implications for chronic low-grade inflammatory diseases in age-related conditions

“…In fact, chronic glutamine supplementation reduces exerciseinduced intestinal permeability while inhibiting NF-κB pro-inflammatory pathways in human PBMC, in a mechanism associated with the activation of HSP70 expression [269]. The same was confirmed in physically active subjects acutely treated with oral doses of glutamine prior to exercise [270]. Increased permeability may be a factor in the pathogenesis of Crohn's disease, which is a chronic inflammatory disease, frequently observed in the elderly, characterized by low-HS response that perpetuates the inflammatory state [306].…”

“…However, human data supporting this assumption are either missing or contradictory [268]. Nevertheless, glutamine supplementation has convincingly been demonstrated to prevent exercise-induced intestinal permeability, possibly through HSF1 activation [269,270].…”