Why is psychosocial stress relevant to human health?
Psychosocial stress is associated with a wide range of health problems in people of all ages. The association between stress and mental health and behavioral outcomes has been studied the most. However, stress is linked to other chronic health problems also. In children, prenatal and postnatal exposure to stress is associated with neurobehavioral disorders, obesity, low birth weight, as well as cardiometabolic disorders. In adults, psychosocial stress is associated with mental health disorders and cardiovascular disease. Recent epidemiological evidence suggests that stress contributes to cellular aging and is a risk factor for specific types of cancer. In addition, stress is linked to substance abuse, such as tobacco, alcohol, and illicit substances which contributes to a broad range of chronic diseases.
What types of questions can be answered?
Questions that can be answered include how stress is related to health outcomes. In addition, depending on the study design, questions can be asked about whether psychosocial stress modulates the effects from toxic environmental exposures, or studies can provide insights into the mechanisms underlying resilience to stress and the associated diseases.
Cortisol levels are useful indicators of the internal impact of psychosocial stress. Biospecimens from highly stressed individuals show chronically elevated levels of cortisol. Studies may investigate the association of cortisol with specific states, such as obesity; with self-reported indicators of stress; or with environmental exposures, such as secondhand smoke). Measurements of cortisol and other stress-related biomarkers can also be used to understand how stress levels change in response to changing psychosocial stressors, health conditions, or environmental exposures. This research can inform strategies and recommendations to protect health.
Another important group of stress biomarkers includes endocannabinoids, such as 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA). The levels of AEA may decrease and the levels of 2-AG may increase in response to stressors. The rate of these changes, such as whether it is immediate or not, depends on the types of stress, such as whether it is acute or chronic. Therefore levels or changes in the relative levels of AEA, 2-AG, and cortisol in response to stressors may help us understand how individuals experience stress and its health effects.
How can exposure to stress be measured?
Analytes and methods: Cortisol and other steroid hormones related to psychosocial stress can be measured by liquid chromatography-tandem mass-spectrometry (LC-MS/MS) or by enzyme-linked immunosorbent assay (ELISA), depending on the sample. Levels of AEA and 2-AG are measured in plasma by LC-MS/MS.
Types of biospecimens: Levels of cortisol and other steroid hormones can be measured in samples of hair, serum, plasma, and saliva. Hair is the most reliable source for assessing chronic stress, as it provides a stable measurement over time. Cortisol levels in serum, plasma, and saliva display diurnal variations. For AEA and 2-AG, plasma is generally used.
How does HHEAR ensure the quality of its analyses?
Our assays are well validated with respect to accuracy and precision. Most assays use standards and embedded controls and blanks. Positive control samples are used to determine the accuracy, precision, low limit of detection, and low limit of quantification of all assays. Internal quality controls for both the low and high ends of detection ranges are included in all assays.
What sample quality and quantity are necessary?
The quantity of sample needed depends on the biomarker being analyzed. Generally, we need up to 1 mL of plasma, serum, or saliva, or at least 10 mg of hair.
If you want to store biospecimens for future analysis by HHEAR Lab Hubs, request a consultation with a HHEAR Lab Hub for information regarding sample collection, preparation, and storage techniques to ensure the quality of the specimens.
References
Lee DY, Kim E, and Choi MH. Technical and clinical aspects of cortisol as a biochemical marker of chronic stress. BMB Reports. 2015; 48(4):209-216.
Hillard CJ. Stress regulates endocannabinoid-CB1 receptor signaling. Seminars in Immunology. 2014; 26:380-388.
Mazier W, Saucisse N, Gatta-Cherifi B, Cota D. (2015) The endocannabinoid system: pivotal orchestrator of obesity and metabolic disease. Trends in Endocrinology & Metabolism. 2015; 26:524-537.