Salivary nerve growth factor response to intense stress: effect of sex and body mass index.
Ample evidence links stress to psychiatric and neurological disease. Although many studies examine stress hormone secretion and receptor activity, exciting new developments signify a shift in focus to neuromodulatory systems influencing neuronal development, survival, and neuroplasticity. The purpose of this study was to characterize salivary nerve growth factor (sNGF) responses to intense stress exposure in healthy military members undergoing survival training. A second purpose was to explore effects of age, sex, education, and body mass index (BMI). One hundred sixteen military members (80% male) were studied before, during, and 24 h after a stressful mock-captivity exercise. sNGF was measured at all three time points. Reactivity, recovery, and residual elevation of sNGF were computed. General linear modeling with repeated measures evaluated effect of stress exposure, as well as the roles of age, sex, education, and BMI. sNGF increased 137% from baseline to intense stress. During recovery, sNGF remained elevated an average of 67% above baseline (i.e., residual elevation). Men showed greater sNGF reactivity than women quantified by larger absolute T1-T2Δ (+148.1 pg/mL vs. +64.9 pg/mL, p<0.017). A noteworthy trend of higher sNGF concentrations in low BMI participants was observed (p=0.058). No effects of age or education were shown. This study shows substantial reactivity and residual elevation of sNGF in response to intense stress exposure in healthy humans. Further research is needed to refine the sNGF assay, fully characterize the sNGF stress response, delineate correlates and mechanisms, and validate therapeutic applications.
Biobehavioral Sciences Lab, Warfighter Performance Department, Naval Health Research Center, San Diego, CA, USA; Institute for Interdisciplinary Salivary Bioscience Research, Arizona State University, Tempe, AZ, USA; School of Exercise and Nutritional Sciences, San Diego State University, San Diego, CA, USA. Electronic address: marc.taylor@med.navy.mil.
Marcus K
MK
Taylor
Institute for Interdisciplinary Salivary Bioscience Research, Arizona State University, Tempe, AZ, USA; Department of Psychology, University of Oregon, Eugene, OR, USA. Electronic address: hlaurent@uoregon.edu.
Heidemarie K
HK
Laurent
Biobehavioral Sciences Lab, Warfighter Performance Department, Naval Health Research Center, San Diego, CA, USA.
Gerald E
GE
Larson
Biobehavioral Sciences Lab, Warfighter Performance Department, Naval Health Research Center, San Diego, CA, USA; School of Exercise and Nutritional Sciences, San Diego State University, San Diego, CA, USA.
Mitchell J
MJ
Rauh
Naval Special Warfare Center, San Diego, CA, USA.
Melissa D
MD
Hiller Lauby
Institute for Interdisciplinary Salivary Bioscience Research, Arizona State University, Tempe, AZ, USA; Johns Hopkins School of Nursing and Bloomberg School of Public Health, Baltimore, MD, USA.
Douglas A
DA
Granger
D000375:Aging / Q000378:metabolism; D015992:Body Mass Index; D004522:Educational Status; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D008297:Male; D008889:Military Personnel; D020932:Nerve Growth Factor / Q000378:metabolism*; D012463:Saliva / Q000378:metabolism*; D012727:Sex Characteristics; D013315:Stress, Psychological / Q000378:metabolism*; D055815:Young Adult
D020932:Nerve Growth Factor; D006854:Hydrocortisone
Body mass index; Military; Nerve growth factor; Plasticity; Sex differences; Stress; Survival