The Effects of Stress on Your Body
When you are stressed, your hypothalamus triggers the release of the stress hormones, cortisol and adrenaline, which in turn triggers your body’s fight or flight response. Your heart races, your breath quickens, and your muscles tense. This response was designed to protect your body in an emergency by preparing you to react quickly; but when the stress response continues day after day, it puts your health at serious risk.
Chronic stress is a factor that affects your mental health as well as your respiratory and cardiovascular systems. During a stress response, you breathe faster to distribute oxygen-rich blood to your body quickly, your heart pumps faster, stress hormones cause your blood vessels to constrict and divert more oxygen to your muscles, and your liver produces extra blood sugar (glucose) to give you a boost of energy. If the stress is chronic, it causes difficulty in breathing, high blood pressure, and may even trigger type II diabetes. Stress can even impact a man’s testosterone levels and affect the menstrual cycle for women.
Stress and Cancer
Cancer patients may find the disease's physical, emotional, and social effects stressful. Those who attempt to manage their stress with risky behaviours, such as smoking or drinking alcohol, or become more sedentary, may have a poorer quality of life after cancer treatment. In contrast, those who use effective coping strategies to deal with stress, such as therapy and stress management techniques, have lower levels of depression, anxiety, and symptoms related to cancer and its treatment.
Experimental studies suggest that psychological stress can affect a tumour’s ability to grow and spread. Emotional and social support can help patients learn to cope with psychological stress. Such support can reduce levels of depression and anxiety, which in turn reduces disease- and treatment-related symptoms among patients.
Some expert organizations recommend that all cancer patients be screened for distress early in the course of treatment. Some also recommend re-screening at critical points along the course of care. Health care providers can use various screening tools, such as a distress scale or questionnaire, to gauge whether cancer patients need help managing their emotions or with other practical concerns. Patients who show moderate to severe distress are typically referred to appropriate resources, such as a clinical health psychologist, social worker, chaplain, or psychiatrist.
Science & Your Angel
The YourAngel Cortisol POC Test is a novel, rapid cortisol test using patient saliva. The test offers a referral system that links a patient with a psychologist to reduce their stress. This is beneficial for the patient’s physical health and can improve treatment (e.g., cancer treatment). The test also allows the patient to monitor the effectiveness of their therapy.
Methods for Monitoring Cortisol
Cortisol Levels in Saliva
Cortisol levels can be monitored using saliva, urine, sweat, or blood. However, saliva monitoring methods are preferred due to the strong correlation between blood and saliva cortisol levels and the non-invasiveness of the test.
Aptamers are single-stranded DNA or RNA ligands that are synthesized in vitro towards specific targets. Aptamers have several advantages over antibodies, such as:
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Easy synthesis
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Adaptive modification
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Small size
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Higher stability
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No immunogenicity
Cortisol levels fluctuate throughout the day, peaking in the morning and decreasing throughout the day. Typical cortisol levels are 3.7-6ng/mL in the morning and 0.3-1ng/mL at night in saliva. Levels above these ranges are high and indicate the need for clinical therapy. The test should be taken in the morning before breakfast when levels are highest since the Cortisol POC Test has a working range of 0.5-15ng/mL. Nighttime cortisol levels are too low for accurate detection.
Figure 1. Aptamer-Based Lateral Flow Assay Design
Figure 2. Cortisol Duplex Aptamer Dissociation. a) represents the conjugated aptamer b) represents aptamer dissociation in the presence of cortisol
Cortisol aptamer-based lateral flow strips are composed of a sample pad where the saliva is placed along with the AuNP conjugates and a buffer solution, a conjugate pad that releases blocking agents (5% BSA, 20mM Na3PO4, 10% sucrose, 0.025% Tween 20) to reduce non-specific binding, a nitrocellulose membrane that acts as a substrate for reaction and detection, and a wicking pad to ensure capillary flow (Figure 1).
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The AuNP conjugates have a gold nanoparticle that is bound to a thiolated DNA capture probe. The capture probe is bound to a cortisol aptamer. The LFA strips have a test DNA line and control DNA line, where the AuNP conjugates will always bind to the control line and only bind to the test line in the presence of cortisol due to duplex aptamer dissociation (Figure 2). AuNP conjugate binding leads to desorption from the AuNP surface. The free AuNPs react with the immobilized cysteamine on the nitrocellulose surface, causing a red colour shift which enables visual detection of cortisol.
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The YourAngel Cortisol POC Test has 4 lines with increasing DNA and cysteamine concentration to detect 2, 4, 6, and 8 ng/mL cortisol levels. This detection creates a gradient-like result, making it easier for the user to determine if their cortisol levels are above the threshold.