Lung Microbiome

Original Editor - Lucinda hampton

Top Contributors - Lucinda hampton and Vidya Acharya  

Introduction

The lung is a specialised elaborate organ system whose functions are impacted by various factors such as oxygen abundance; its interdependence (through a compacted net work of capillaries) to the extrapulmonary systems; and a range of immune cells living in the tissue at steady state. The lung also is host to a small biomass populace of commensal microorganisms that are active during both health and disease, and are able to adjust regulatory immune responses during cancer and infections.

The lung microbiota is diverse as compared to other organs due to its access to oxygen and the presence of a wide range of airborne substrates. As the upper respiratory tract and oropharynx are heavily populated with microbes and directly communicate with lungs, the lungs are constantly subjected to microbial immigration as well as elimination through mucosal defense and mucociliary clearance mechanism. As a result of the bidirectional movement of air, mucus, and microorganisms in the lungs, the microbiome of the lungs is more dynamic and transient. Modern research using techniques to identify the bacteria show a presence of a consistently-detected diverse bacterial signal in the lung of healthy humans.

The Lung Microbiome: Lung and Brain Disease

The lung microbiome includes bacteria, archaea, fungi, protozoa, and viruses. In disease state (such as chronic lung disease or lung cancer), the microbial homeostasis is disrupted and changes occur in the microbial community. The lung microbiota appears to be involved in promoting the amassing of immunosuppressive cells, preventing unfavourable inflammatory reactions to benign stimuli. eg in patients with pulmonary diseases (a risk factors for lung cancer), the microbiota that greatly differs from that of healthy lungs; chemicals present in the tobacco smoke potentially affect lung immune cells function and smoking may cause a change in the microbiota–immune cell cross talk, leading to imbalance in the system, then chronic infection and, eventually, lung cancer.

The lung microbiome may well play an important role in contributing to the occurrence and development of not only lung diseases but additionally diseases originating in the central nervous system. e.g an close relationship exists between the lung microbiome and multiple sclerosis. The role of the lung microbiome in brain diseases (eg Parkinson’s disease, Alzheimer’s disease, intracerebral hemorrhage) warrants research. As known the gut microbiota is able to influence brain function through eg metabolites originating from the microbiota. With this in mind it is thought that the lung microbiota may affect the brains' health .

Antibiotic And Lung Microbiome

The maintenance of homeostasis and preventing pathogen invasion depends on the microbiome. The dynamic equilibrium of the body microbiota, including the lungs, can be disrupted by antibiotic use. For example, alterations of the gut microbiome can alter immune responses at distal sites. Research suggests that antibiotic treatment alters gut microbiota, leading to increased fungal colonization and significantly exacerbating the allergic response to intranasal mold spore, Aspergillus fumigatus. Antibiotic use affects the success of certain immunotherapies. Research proposes that antibiotic use can diminish the efficacy of immune checkpoint inhibitor therapy in lung cancer patients.