Tattoos Effect Local Sweat Excretion Rate of Epidermal Growth Factor During Outdoor Group Fitness Exercise

Abstract

There is interest in the potential of sweat cytokines to serve as non‐invasive biomarkers to monitor immune system function, but many practical questions remain. For example, sweat constituents collected from tattooed (TAT) skin regions may differ from skin regions without permanent tattooing. The purpose of this investigation was to determine if tattooed skin (TAT) differed from contralateral non‐tattooed skin (NT) for sweat cytokines including: EGF, IL‐10, IL‐1α, IL‐1β, IL‐6, IL‐8, TNF‐α, and IL‐31 concentrations and excretion rates during a group fitness exercise session. Moderately trained individuals (males n=8, females n=8, 34±8 y) with at least one permanent tattoo on the upper body (wrist, forearm, tricep, bicep, scapula, shoulder, or torso) participated in a ~60 minute outdoor (~27±3°C, 63±4% RH) group fitness exercise session. Absorbent patches (3M Tegaderm™ + Pad) were used to collect sweat on both TAT and NT skin. Patches were monitored during the exercise session and removed upon moderate saturation. Sweat cytokine concentrations were measured using Multiplex (EMD Millipore, MagPix) customized kits. Local sweat rate (LSR) was calculated from sweat mass over patch surface area (11.9 cm2) and duration of exercise (56±2 min). Excretion rates were calculated as the product of LSR and cytokine concentration. To evaluate differences between TAT and NT skin, paired t‐tests or Wilcoxon signed rank tests were used. Significance level was set at p<0.05. Data are presented as mean±SD for normally and non‐normally distributed data. There were no differences in LSR for TAT vs. NT skin regions (1.20±0.62 vs 1.24±0.53 mg/cm2/min; p=0.70). There were no differences between TAT and NT skin for concentrations of EGF (45±29 vs 53±31 pg/mL; p=0.10), IL‐10 (0.03±0.04 vs 0.07±0.13 pg/mL; p=0.21), IL‐1β (1.66±1.12 vs 1.86±1.07 pg/mL; p=0.55), IL‐8 (0.60±0.50 vs 0.56±0.64 pg/mL; p=0.27), IL‐1α (618±550 vs 807±913 pg/mL; p=0.3) or TNF‐α (0.40±0.05 vs 0.40±0.04 pg/mL; p=0.85). There was below minimum or no level of detection for TAT and NT skin for IL‐6 and IL‐31. Excretion rates were significantly different between TAT and NT skin for EGF (0.05±0.04 vs 0.06±0.03 pg/cm2/min; p=0.04). In summary, EGF excretion rate was lower in TAT skin than NT skin during exercise, but TAT did not affect the concentrations or excretion rates of any other cytokines measured.