Abstract
Purpose :
To analyze inter-individual differences and intersession variability in potential salivary ocular pain biomarkers on healthy subjects, under the influence of controlled environmental conditions, and compare their concentration with data from a previous study in non-controlled conditions
Methods :
Healthy subjects were exposed for 30 minutes in the Controlled Environmental Research Laboratory (CE-Lab, Vision R&D, Spain) under standard environmental conditions (22 C, 50% relative humidity) in two separate visits (V1, V2) at least 24 hours apart. Saliva was collected after the exposure to standard conditions in each of the visits, and cortisol, α-amylase (sAA), testosterone, and soluble fraction of TNFα receptor II (sTNFαRII) were analyzed by ELISA. Repeatability of intra-subject inter-day measurements was assayed by intraclass correlation coefficient (ICC)
Results :
Thirty-four subjects were included (mean age: 35.44±3.57; range 30-40 yrs; 14 male/20 female). After exposure, the cortisol concentration was significantly higher at V1 (7.79 ± 2.06 μg/dL) compared to V2 (7.11 ± 1.70 μg/dL) (p<0.035), whereas the sAA concentration was lower at the V1 (42.74 ± 32.17 U/mL) compared to V2 (61.15 ± 42.72 U/mL) (p<0.001). There were no significant differences in testosterone (p = 0.250) and sTNFαRII (p = 0.638) salivary concentration between both visits.
The analysis of ICC value showed that sTNFαRII had the highest (0.987) indicating good intersession reproducibility. Testosterone and sAA ICCs were 0.606 and 0.420 respectively, which were at the limit of acceptability. Cortisol had the lowest ICC value (0.169), indicating a very poor repeatability between V1 and V2. Testosterone and sTNFαRII ICCs in subjects exposed to controlled environmental conditions were higher than those found previously by our group in a study in healthy subjects under non-controlled environmental conditions (Sobas PLOS one 2016)
Conclusions :
The reproducibility of the measurement of sTNFαRII, sAA and testosterone in saliva in healthy subjects improved when analyzed after exposure under controlled environmental conditions. Environmental factors such as temperature and humidity affect the reproducibility of the different ocular pain biomarkers. If these molecules are to be used as biomarkers of chronic ocular pain, it will be necessary to control environmental factors
This is a 2020 ARVO Annual Meeting abstract.