Mold that grows on nuts or corn forms toxins that can weaken airways and immunity, according to researchers at the Perelman School of Medicine at the University of Pennsylvania. The study results are published in Nature Scientific Reports.
Poisonous and cancer-causing aflatoxins contaminate 25% of the world’s food crops, as well as many grain-based livestock and pet foods. These mycotoxins, which are produced by certain fungi that grow on and in certain foods, can cause allergic fungal rhinosinusitis and bronchopulmonary aspergillosis, two infections that can be treated with antifungal medications and surgery, if needed.
The latest study showed that acute exposure to aflatoxins slowed down key defense mechanisms in the airways. Laboratory imaging showed impairment of mucosal ciliary clearance (MCC) and ciliary beat frequency (CBF), suggesting that aflatoxins enhance the pathogenicity of the fungi. They may also do so for other co-infecting pathogens like bacteria.
“With these defenses impaired, it may create a window of opportunity for the infection, and potentially a domino effect,” said lead author Robert J. Lee, an assistant professor in the departments of otorhinolaryngology: head and neck surgery and physiology at Penn.
Senior author Noam A. Cohen, an associate professor of otorhinolaryngology at Penn, said, “Patients may become more susceptible to upper respiratory infections and chronic rhinosinusitis (CRS) that can ‘seed’ lower respiratory infections, especially in those with a compromised immune system. It can also exacerbate the more severe lung diseases, such as cystic fibrosis or chronic obstructive pulmonary disease.”
The study also showed that fungal toxins activate protein kinase C (PKC), which decreases ciliary beat frequency and thus decreases MCC. This shows potential for treatment. The researchers found that CBF reductions could be blocked by the anti-inflammatory drugs Gö6983 and calphostin C, which are PKC inhibitors. This suggests that similar anti-inflammatories could potentially be used to treat the fungal infection and prevent further co-infections.
The use of anti-inflammatory drugs to treat these infections could lessen the need for patients—human and animal—to use antibiotics. Upper respiratory infections often lead to CRS, a driver of antibiotic resistance.
The next step is for the researchers to examine longer-term effects of aflatoxins, to learn more about chronic exposure and its effect on airways