Background

In biological terms, stress is any stimulus that places a demand on an organism and therefore is neither good nor bad. But should this demand persist for either a short period of time, or a long period, the human body has developed mechanisms to handle such demands. Within the body, there are two main forms of stress: acute and chronic. Acute stress is a form of stress that is short term, lasting between 3 days and 1 month, according to the DSM5-TR (2022). Juxtaposed to this, long-term, chronic stress, which is long-term stress lasting for a period of time greater than 1 month, according to a study conducted by Yale University’s School of Medicine (2022). As acute stress precedes chronic stress and chronic stress leads to poor quality of life which translates to billions of dollars lost in economic output (Davis et al., 2017), we proposed finding a biomarker for acute stress as a means to intervene before acute stress leads to chronic stress.

Biomarkers for Stress

Long-term, chronic stress has been known to see the presence of and corresponds to elevated levels of the hormone cortisol. This hormone serves as a strong indicator of chronic stress because it takes much longer to express as it is a lipid molecule. Cortisol has a wide variety of effects on many organs and tissues throughout the body as described by Thau et al. in their 2022 publication. Conversely, Ali and Nater (2020) have described that acute stress can be detected through the presence of the enzymatic protein, alpha-amylase (AA), which is secreted in the saliva, and has a relatively quick expression. For these two reasons, quick and concentrated levels of expression as well as ease of access, we propose using AA as a biomarker for acute stress.

Limitations of Current Methods

Unfortunately, current acute and chronic stress detection methods are flawed. According to the Cleveland Clinic, there are three current standard of practice (SOP) means to test for cortisol but in order to quantify the chronic stress hormone cortisol, this requires a blood sample. Blood samples are often viewed as invasive and expensive to process as they require a medical lab and specialized technicians.

As our team is based in New York City, and as New York City has an incredibly diverse population, part of our desire for this project is to be more altruistic for our patient population to respect these patients, their economic background, and their cultural views. A blood draw may not only be seen as a conflict with the patient’s views on medicine but as a conflict with their culture and we are trying to respect both. This is why we are proposing the less invasive method using an AA based spit test, which the Cleveland Clinic has omitted as these tests are not yet developed enough to be relied upon.

Solution

Looking to traditional manufacturing, we have found three over the counter (OTC), colorimetric ELISA kits for detecting cortisol in plasma or serum using a 96 well plate. These include AbCam at $730, Enzo at $414, and one from ThermoFisher for $590. From these suppliers alone, we see evidence of a cortisol test being both invasive, as it requires blood or serum, expensive, with a mean price of $579, and requiring specialized training and equipment.

The traditional way to quantify alpha-amylase is to obtain spit samples using an ELISA. This process is still imperfect - despite how it is non-invasive but does not remove the need for lab technicians. Additionally, it is still relatively expensive. Such tests with similar requirements exist for salivary alpha-amylase as well from suppliers such as Salimetrics for $354, Novus Biologics for $649, Innovative Research at $700, and LSBio at $798; with a mean price of $625 for a single test. EmpireSpit’s solution is to utilize the non-invasive spit collection combined with the inexpensive aptamer-based detection system that assesses our protein biomarker. This approach would follow a similar manner to that of an at-home pregnancy test (which detects HCG).

In a previous study (2017), their results showed that acute stress leads to chronic stress. In turn, chronic stress can lead to anxiety which can further lead to severe depression. Our goal of creating an inexpensive and non-invasive aptamer-based salivary test kit is to quickly detect acute stress so medical professionals can intervene before acute stress can progress into chronic stress.

References

“Va.Gov: Veterans Affairs.” Acute Stress Disorder, 7 May 2007, www.ptsd.va.gov/professional/treat/essentials/acute_stress_disorder.asp.

“Chronic Stress.” Yale Medicine, Yale Medicine, 6 Aug. 2022, www.yalemedicine.org/conditions/stress-disorder.

Neurobiology of Chronic Stress-Related Psychiatric Disorders: Evidence ..., www.ncbi.nlm.nih.gov/pmc/articles/PMC5976254/. Accessed 11 Oct. 2023.

Physiology, Cortisol - Statpearls - NCBI Bookshelf, www.ncbi.nlm.nih.gov/books/NBK538239/. Accessed 11 Oct. 2023.

Salivary Alpha-Amylase as a Biomarker of Stress in Behavioral Medicine, www.ncbi.nlm.nih.gov/pmc/articles/PMC7250801/. Accessed 11 Oct. 2023.

Cleveland Clinic. “Cortisol Test: What It Is, Types, Purpose & Results.” Cleveland Clinic, my.clevelandclinic.org/health/diagnostics/22417-cortisol-test. Accessed 11 Oct. 2023.

Cleveland Clinic. “Amylase Test: What It Is, Purpose, Procedure & Results.” Cleveland Clinic, my.clevelandclinic.org/health/diagnostics/22386-amylase-test. Accessed 11 Oct. 2023.

“Cortisol Elisa Kit (AB108665).” Abcam, 9 Oct. 2023, www.abcam.com/products/elisa/cortisol-elisa-kit-ab108665.html.

“Cortisol Elisa Kit.” Cortisol ELISA Kit - ADI-900-071 - Enzo Life Sciences, 18 May 2022, www.enzolifesciences.com/ADI-900-071/cortisol-elisa-kit/.

“Cortisol Competitive Human Elisa Kit.” Cortisol Competitive Human ELISA Kit - Invitrogen, www.thermofisher.com/elisa/product/Cortisol-Competitive-Human-ELISA-Kit/EIAHCOR.

Measuring Salivary Alpha-Amylase in the Undergraduate Neuroscience ..., www.ncbi.nlm.nih.gov/pmc/articles/PMC5777833/. Accessed 12 Oct. 2023.

Cleveland Clinic. “Pregnancy Test: When to Take, Types & Accuracy.” Cleveland Clinic, my.clevelandclinic.org/health/diagnostics/9703-pregnancy-tests. Accessed 11 Oct. 2023.

“Human Amy1a / Salivary Amylase (Sandwich Elisa) Elisa Kit - LS-F4700.” LSBio, www.lsbio.com/elisakits/human-amy1a-salivary-amylase-sandwich-elisa-elisa-kit-ls-f4700/4700. Accessed 11 Oct. 2023.

“Human Amylase Alpha 1 Salivary Elisa Kit.” Innovative Research, www.innov-research.com/products/human-amylase-alpha-1-salivary-elisa-kit. Accessed 11 Oct. 2023.

“Human Salivary Amylase Alpha Elisa Kit (Colorimetric).” Novus Biologicals, www.novusbio.com/products/salivary-amylase-alpha-elisa-kit_nbp2-68204. Accessed 11 Oct. 2023.

“Salivary Alpha-Amylase Enzymatic Kit.” Salimetrics, 6 Apr. 2020, salimetrics.com/assay-kit/salivary-alpha-amylase-enzymatic-assay/.