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. 2023 Feb 22;18(2):e0282007.
doi: 10.1371/journal.pone.0282007. eCollection 2023.

Peripheral brain-derived neurotrophic factor (BDNF) and salivary cortisol levels in college students with different levels of academic stress. Study protocol

Juan-Luis Castillo-Navarrete  1   2 , Alejandra Guzmán-Castillo  2   3   4 , Claudio Bustos  2   5 , Romina Rojas  2   6
Affiliations

Peripheral brain-derived neurotrophic factor (BDNF) and salivary cortisol levels in college students with different levels of academic stress. Study protocol

Juan-Luis Castillo-Navarrete et al. PLoS One. .

Abstract

Introduction: Brain-derived neurotrophic factor (BDNF) is essential for brain physiological processes influencing memory and learning. BDNF levels can be affected by many factors, including stress. Stress increase serum and salivary cortisol levels. Academic stress is of the chronic type. BDNF levels can be measure from serum, plasma or platelets, and there is still no standard methodology, which is relevant to ensure reproducibility and comparability between studies.

Hypothesis: (i) BDNF concentrations in serum show greater variability than in plasma. (ii) In college students with academic stress, peripheral BDNF decreases and salivary cortisol increases.

General objective: To standardize plasma and serum collection for BDNF levels and to determine whether academic stress affects peripheral BDNF and salivary cortisol levels.

Design: Quantitative research, with a non-experimental cross-sectional descriptive design.

Participants: Student volunteers. Under convenience sampling, 20 individuals will be included for standardization of plasma and serum collection and between 70 and 80 individuals to determine the effect of academic stress on BDNF and salivary cortisol.

Peripheral blood and salivary cortisol sampling, measurements: 12 mL of peripheral blood (with and without anticoagulant) will be drawn per participant, separated from plasma or serum and cryopreserved at -80°C. Additionally, they will be instructed in the collection of 1 mL of saliva samples, which will be centrifuged. Val66Met polymorphism will be performed by allele-specific PCR, while BDNF and salivary cortisol levels will be determined by ELISA.

Statistical analysis: (i) descriptive analysis of the variables, through measures of central tendency and dispersion, and the categorical variables through their frequency and percentage. (ii) Then a bivariate analysis will be performed comparing groups using each variable separately.

Expected results: We expect to (i) determine the analytical factors that allow a better reproducibility in the measurement of peripheral BDNF, and (ii) the effect of academic stress on BDNF and salivary cortisol levels.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Schematic of both the labeling procedure and the centrifugation of each tube in which the peripheral blood sample will be obtained.
Each participant will have 12 ml of peripheral blood (04 tubes) drawn using 02 tubes with EDTA K3 as anticoagulant and 02 tubes without additives (to obtain serum). The peripheral blood samples obtained will be centrifuged for 10 min at 2500 g and then either plasma or serum will be aliquoted and stored at -80°C until processing. In the case of samples with EDTA K3 as the anticoagulant, one tube shall be centrifuged as soon as the blood sample is withdrawn and the other tube after 30 min at room temperature. For samples without anticoagulant, one tube shall be centrifuged after 10 min at room temperature and the other after 30 min.
See this image and copyright information in PMC

References

    1. Jasny BR, Chin G, Chong L, Vignieri S. Again, and Again, and Again …. Science (1979) [Internet]. 2011. Dec 2 [cited 2022 Jun 7];334(6060):1225. Available from: https://www.science.org/doi/full/10.1126/science.334.6060.1225 - DOI - PubMed
    1. Matarese V. Kinds of Replicability: Different Terms and Different Functions. Axiomathes [Internet]. 2022. Jan 27 [cited 2022 Jun 7];1–24. Available from: https://link.springer.com/article/10.1007/s10516-021-09610-2 - DOI
    1. Castillo-Navarrete JL. Efecto del estrés académico sobre los niveles plasmáticos de BDNF y el porcentaje de metilación global del ADN. Estudio piloto. 2020. Nov 27; Available from: http://repositorio.udec.cl/jspui/handle/11594/598
    1. Polacchini A, Girardi D, Falco A, Zanotta N, Comar M, de Carlo NA, et al.. Distinct CCL2, CCL5, CCL11, CCL27, IL-17, IL-6, BDNF serum profiles correlate to different job-stress outcomes. Neurobiol Stress. 2018. Feb 1;8:82–91. doi: 10.1016/j.ynstr.2018.02.002 - DOI - PMC - PubMed
    1. Polyakova M, Schlögl H, Sacher J, Schmidt-Kassow M, Kaiser J, Stumvoll M, et al.. Stability of BDNF in Human Samples Stored Up to 6 Months and Correlations of Serum and EDTA-Plasma Concentrations. International Journal of Molecular Sciences 2017, Vol 18, Page 1189 [Internet]. 2017 Jun 3 [cited 2022 Sep 7];18(6):1189. Available from: https://www.mdpi.com/1422-0067/18/6/1189/htm doi: 10.3390/ijms18061189 - DOI - PMC - PubMed

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