Effects of oral glutamine supplementation on exercise-induced gastrointestinal permeability and tight junction protein expression

• Published in: Journal of applied physiology (1985) Vol. 116; no. 2; pp. 183 - 191
• Main Authors: Zuhl, Micah N., Lanphere, Kathryn R., Kravitz, Len, Mermier, Christine M., Schneider, Suzanne, Dokladny, Karol, Moseley, Pope L.
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 15.01.2014
• Subjects: Administration, Oral; Adult; Caco-2 Cells; Cell Line; Dietary Supplements; DNA-Binding Proteins - metabolism; Epithelial Cells - drug effects; Epithelial Cells - metabolism; Exercise; Exercise - physiology; Female; Gastrointestinal diseases; Gastrointestinal Tract - drug effects; Gastrointestinal Tract - metabolism; Glutamine - administration & dosage; Heat Shock Transcription Factors; Hot Temperature; HSP70 Heat-Shock Proteins - metabolism; Humans; I-kappa B Proteins - metabolism; Intestinal Absorption - drug effects; Leukocytes, Mononuclear - drug effects; Leukocytes, Mononuclear - metabolism; Male; NF-KappaB Inhibitor alpha; Permeability; Physiology; Proteins; Tight Junction Proteins - metabolism; Tight Junctions - drug effects; Tight Junctions - metabolism; Transcription Factors - metabolism; Up-Regulation - drug effects; Young Adult; exercise; tight junction; permeability
• ISSN: 8750-7587; 1522-1601; 1522-1601
• DOI: 10.1152/japplphysiol.00646.2013

The objectives of this study are threefold: 1) to assess whether 7 days of oral glutamine (GLN) supplementation reduces exercise-induced intestinal permeability; 2) whether supplementation prevents the proinflammatory response; and 3) whether these changes are associated with upregulation of the heat shock response. On separate occasions, eight human subjects participated in baseline testing and in GLN and placebo (PLA) supplementation trials, followed by a 60-min treadmill run. Intestinal permeability was higher in the PLA trial compared with baseline and GLN trials (0.0604 ± 0.047 vs. 0.0218 ± 0.008 and 0.0272 ± 0.007, respectively; P < 0.05). IκBα expression in peripheral blood mononuclear cells was higher 240 min after exercise in the GLN trial compared with the PLA trial (1.411 ± 0.523 vs. 0.9839 ± 0.343, respectively; P < 0.05). In vitro using the intestinal epithelial cell line Caco-2, we measured effects of GLN supplementation (0, 4, and 6 mM) on heat-induced (37° or 41.8°C) heat shock protein 70 (HSP70), heat shock factor-1 (HSF-1), and occludin expression. HSF-1 and HSP70 levels increased in 6 mM supplementation at 41°C compared with 0 mM at 41°C (1.785 ± 0.495 vs. 0.6681 ± 0.290, and 1.973 ± 0.325 vs. 1.133 ± 0.129, respectively; P < 0.05). Occludin levels increased after 4 mM supplementation at 41°C and 6 mM at 41°C compared with 0 mM at 41°C (1.236 ± 0.219 and 1.849 ± 0.564 vs. 0.7434 ± 0.027, respectively; P < 0.001). GLN supplementation prevented exercise-induced permeability, possibly through HSF-1 activation.