Scientists take the so far almost unexplored lung microbiome into focus

The bowel microbiome is pretty thoroughly explored by now. On the contrary, there is little known about the lung microbiome, so far. It was only recently that scientists found out that the lung is not a sterile place. And only within the last couple of years, it came into our awareness that also our lung is home to a number of tiny helpers residing there to help protect our health. In April 2019, the Apotheken Umschau published an interview with the microbiologist Prof. Michael Schloter of the Munich Helmholtz-Zentrum (>>> Interview). Here is a little abstract on the latest findings:

What do we know about the lung microbiome?

We do know by now that it actually does exist. And that was not the case for quite a long time. To prove and decipher the lung microbiome is relatively difficult, as there are drastically less microbes in the lung in comparison to the bowel and they are especially slow growing, too. So, it can be seen as a first, big success that the lung microbiome is explored, at all.

We are also certain about the prevalence of Prevotella Bacteria (>>> Prevotella) in the lung. Prevotella can also be found in the bowel, mouth, and vagina. They seem to have a certain function for our body, but we are still speculating on what exact function that might be.

What is the function of the lung microbiome?

We have not been able to find a concise definition on the function of the lung microbiome, but all research up to now is hinting at three main functions: First, the lung microbiome is a barrier to bad bacteria. If the microbiota in the lung really have a function is still to be proved, but in any case, it is better for the human body to allow “friendly” bacteria to dwell in and on him and thus preventing “hostile” bacteria to take their place, because also with bacteria, living space has to be conquered. Second, the immune system is stimulated. Allowing “good” bacteria makes the immune system even more reactive to “bad” bacteria. And third, the microbes in the lung help degrading harmful substances that get into the body via respiration. Similar to the bowl microbiome, the lung microbiome is something like a gatekeeper preventing dangerous substances to enter the system.

What harms the lung microbiome?

Smoking, in the first place (see also our related article: Smoking seriously harms you - and your microbiome). But also other nanoparticles can enter the lung, coming from exhaust gases, pollutants, tiny particles in the air, and other impacts. They then “stick” onto the alveoli and either react with the substances located there, impairing their actual function, or they irritate the lung tissue, hindering positive substances from passing into the body, or enter the body as harmful substances, themselves.

The most obvious sign for a dysfunctional lung microbiome is asthma. Asthma can be considered one of the most widespread diseases, what makes us seriously suspect our air quality in general.

What can we do if our lung microbiome is impaired?

First, we should try and cut down all disruptive factors, which means give up smoking and avoid areas of strong pollution. Doctors advise also and especially patients suffering from asthma to do sports and exercise in fresh air, to stimulate the lung function.

Science is right now doing research on probiotic treatments for the lung microbiome. At the moment, the tendency is to positively change the “bacterial communication net” aiming for substances positively altering the microbiome. And here we get back to the bowel microbiome. Giving D amino acids, for instance, can result in metabolic products that then circulate via the blood and get into the lungs, coming to full effect there. Studies performed on mice could show a reduction of asthma symptoms by D amino acids. In how far this finding can be transferred to humans, is content of subsequent studies.

In any case, the long time neglected and unknown microbiome is pretty much in the focus now.