The lungs were long considered sterile in health, while in diseases such as chronic obstructive pulmonary disease (COPD) it was thought that failure in immune mechanisms allowed microorganisms to proliferate and persist. New sequencing technologies have shown that many microorganisms are present in the lungs of healthy individuals as well. Few studies have examined the fungal community in COPD and compared it to healthy controls using such techniques. According to the results of the study, it appears that the combinations of these environments were not affected by the use of inhaled stimulants.
The lungs have a unique fungal environment
The Bergen COPD Microbiome (abbreviated “MicroCOPD”) study is the world’s largest single center study of the fungal community in the lungs of people with COPD. The Bergen Respiratory Research Group collected lung samples from 233 people with and without COPD using bronchoscopy. Lung and mouth samples from 193 of these individuals were then sequenced to detect the resident fungi.
“The results show that both healthy and diseased lungs have a different fungal composition than the mouth, indicating that the lungs have a unique innate environment,” says doctoral candidate Inar Marius Hellystad Martinsen.
The Candida fungus has taken hold of the lungs. Interestingly, there were no differences in the structures between the lungs of healthy individuals and patients with COPD. Moreover, patients with COPD who used inhaled steroids had no differences in the innate community in their lungs compared to those without inhaled steroids.
The prevalence and severity of fungal infections has increased in recent years. Thus, the finding that Candida is frequently found in healthy lungs could be of particular interest. Candida is found as a part of natural plants on many mucous membranes, and is capable of causing disease, such as thrush in the mouth or vagina.
“It would be very helpful to have a further examination to see if the fungal lung infection is due to fungi already present in the lungs,” says Hjellestad Martinsen.
“If this is the case, then focus should be placed on these fungi to uncover the pathogens responsible for transforming them from” friendly residents “in our lungs to intruders causing diseases.
We know that the use of inhaled steroids can have immunosuppressive effects, which can predispose to the growth of fungi. The observation that inhaled steroids do not appear to influence the formation of fungal environments in the lungs is interesting in this regard. Inhaled steroids are frequently used by COPD and asthma patients, so it will be important to learn more about their effect on fungi in the lungs.
The research group consists of several researchers working on bacterial and fungal spores in the lungs, and the group is currently examining whether fungi are also present in other lung diseases.