(Beyond Pesticides, April 28, 2021) New evidence set to be presented at the Experimental Biology (EB) 2021 meeting held this week suggests that Gulf War Veterans and other individuals with prior pesticide exposures may be more susceptible to Covid-19 infection. As the pandemic continues, it is critically important for researchers to better understand specific vulnerabilities in population groups in order to improve care and patient outcomes. “The reason why COVID-19 causes a severe form of disease leading to hospitalization and high rates of mortality in a small segment of society is unclear,” said Prakash Nagarkatti, PhD, co-author of the study and vice president for research at the University of South Carolina. “This work sheds new light on exposure to pesticides and potential susceptibility to COVID-19 through altered immune response.” Â
According to recent data, out of 160,000 Covid-19 cases among veterans, the mortality rate was more than 4%. Researchers are pointing to Gulf War Syndrome, and past exposure to organophosphate pesticides as part of the problem. “We have identified a basic mechanism linked with inflammation that could increase susceptibility to COVID-19 infection among people exposed to organophosphates,” said Saurabh Chatterjee, PhD, from the University of South Carolina.
Interleukin 6 (IL-6) is a protein that has both pro and anti inflammatory properties in the body. Individuals produce these proteins to fight off infections, or to heal injuries to soft tissues. Past research had determined that Gulf War veterans had higher levels of IL-6 than the general population. This can occur under continuously stressful conditions like toxic pesticide exposure, and ongoing production of this protein in oneâ€™s body can cause chronic inflammation and lower immune system response.
To determine how IL-6 and pesticide exposure affect coronavirus infection, researchers exposed Â epithelial cells in a human lung to IL-6 and the insecticide chlorpyrifos for a period of six hours. A control was established that received no exposures. All groups then had the coronavirus â€śspike proteinâ€ť â€“ a protein that protrudes on the outside of the virus and helps it infect cells â€“ applied to certain areas of the epithelial cells (known as the apical and basolateral surfaces, roughly translated to the interior tip and the side of the cells, respectively).
The changes researchers observed dealt with the Angiotensin Converting Enzyme 2 (ACE2) receptor, an enzyme in the body that can lower blood pressure, but also serves as the entryway for coronavirus to infect cells. Cells exposed to IL-6 and chlorpyrifos had much higher ACE2 expression, indicating a higher risk of infection. Additionally, cells exposed to these materials also recorded higher rates of apoptosis, or cell death. “To our knowledge, this is the first study demonstrating that the ACE2 receptor translates from the basolateral cell membrane to the apical cell upon co-exposure to organophosphate and IL-6,” said Dr. Chatterjee.
While the study models exposure induced by pesticide-related stressors, researchers note that the implications may be much farther reaching. “This mechanism could also increase risk for people with metabolic diseases and cancer because they tend to exhibit the same type of inflammation,â€ť said Dr. Chatterjee. Â “Since people with obesity, type 2 diabetes or cancer also have high circulatory IL-6 levels, we think people with these conditions will also have increased susceptibility to SARS-CoV-2 infection because of increased translocation of ACE2 receptor to the apical cell surface.”
This is not the first study to find greater risk of coronavirus infection from past pesticide exposure. A study published in February this year also found that organophosphates increase vulnerability to COVID-19. That research focused on how pesticide exposure can depress immune system functioning. â€śTo curb SARS-CoV-2 infection, a healthy immune system is obligatory despite potent vaccine to alleviate morbidities in patients. But unintentional exposure to OP compounds from several sources can rupture the antiviral defense against SARS-CoV-2. Moreover, respiratory ailments may also be fueled by OP compounds. Hence, SARS-CoV-2 mediated morbidities and fatalities could be backed by unintentional exposure to OPs in patients,â€ť the study authors wrote.
A study published in October of last year also found a mechanism whereby the common fungicide fludioxonil decreases the bodyâ€™s ability to produce an important antioxidant by harming an enzyme common to all cells. Â
Although the stressors and injuries suffered by Gulf War Veterans are in the past, insecticides like chlorpyrifos are ever-present in our conventional food supply. Despite overwhelming data on the dangers of chlorpyrifos and other organophosphates, regulators at the U.S. Environmental Protection Agency continue to permit their use. The Biden administration is reviewing the chemical, but even if eliminated, a range of other hazardous organophosphates remain on the market and in our food supply.
Maintain your health by avoiding chemically farmed foods that contain toxic pesticides and are grown with synthetic fertilizers. Organic farming provides a method to grow healthy food free of hazardous synthetic residues that can elevate our risk of disease. To learn more about the benefits of a safer, healthier, organic food system, sign up today for Beyond Pesticides first ever virtual National Pesticide Forum.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.