The Lab: “Changes in Salivary Antimicrobial Protein Concentrations in Response to Maximal Exercise in Collegiate Swimmers”

ABSTRACT

Salivary Antimicrobial Proteins (sAMPs) play a central role in innate immune responses by exerting their antibacterial and antiviral properties. Acute psychological and physiological stressors reduce sAMPs concentrations, and increase the risk of upper respiratory tract infections (URTI). However, the impact of sustained stressors on sAMPs and their relation to URTI symptoms is unknown.

PURPOSE: To characterize the impact of acute bouts of exercise on sAMPs and symptoms of URTI in collegiate swimmers over a 6-month period.

METHODS: Salivary samples were collected from sixteen NCAA D1 swimmers (8 M, 8 F: 19.8 ± 0.7 yrs) before and after exhaustive in-pool swims at 2 timepoints (V1: immediately post-season 1 and V3: early season 2). An additional V2 mid-off season 1 timepoint was collected in a subset of 10 swimmers. Azurocidin and secretory leukocyte protease inhibitor (SLPI) sAMPs were measured by ELISA, and self-reported measures of stress were collected to assess sleep quality (PSQI) and symptoms of URTI (WURRS-21). Linear mixed models were used to determine the effects of exercise, season timepoint, and their interaction on sAMP concentrations and secretion rates (α=0.05). Pearson’s correlation coefficients were used to determine linear correlations between resting sAMP concentrations and secretion rates with stress measures.

RESULTS: Post-exercise SLPI levels were elevated 8 fold at V2 and  3 fold at V3 when compared to resting values (p<0.05); however, resting SLPI concentrations and secretion rates remained unchanged during the season (p>0.05). Acute exercise was associated with increased Azurocidin concentrations, with the greatest post-exercise increase seen at V2 (p=0.03). Resting salivary Azurocidin concentrations and secretion rates were positively associated with sleep quality (r=0.42, p=0.04 and r=0.49, p=0.02 respectively), while salivary SLPI concentrations were not. Furthermore, resting Azurocidin concentrations were associated with self-reported symptoms of URTI (r=0.52, p=0.03) during all 3 visits.

DISCUSSION: Oral innate immunity in collegiate swimmers is differently impacted by acute maximal exercise over a season. Greater sleep quality appears to promote salivary Azurocidin concentration and oral innate immune health, which could in turn protect athletes against URTIs.

RESEARCHERS

Theall, Bailey1, Kuremsky, Connor A.1; Wang, Haoyan1; Hardin, Kaitlyn1; Lemoine, Nathan1; Marucci, Jack1; Mullenix, Shelly1; Irving, Brian A.1,2 FACSM; Harrell, Brian3; Johannsen, Neil M.1,2; Spielmann, Guillaume 1,2

REFERENCE

Theall, B., Kuremsky, C., Cho, E., Wang, H., Hardin, K., Marucci, J., Mullenix, S., Harrell, B., Irving, B., Johannsen, N. and Spielmann, G., 2019. Changes in Salivary Antimicrobial Protein Concentrations in Response to Maximal Exercise In Collegiate Swimmers: 373: Board# 211 May 29 9: 30 AM-11: 00 AM. Medicine & Science in Sports & Exercise, 51(6), p.96.