Find out how cigarette smoking causes lung cell exhaustion leading to TB

Researchers from Trinity College Dublin unveiled how lung cell exhaustion caused by cigarette smoking affects their power to battle diseases such as TB.

Cigarette smoking is renowned for its adverse health effects and from further research, Trinity College Dublin, Ireland, have discovered how the lung cell exhaustion caused by smoking affects a patient’s ability to fight diseases such as tuberculosis.

Findings were published in the American Journal of Respiratory Cell and Molecular Biology.

Cigarette smoking and lung cell exhaustion

Little is known regarding how cigarette smoking causes the susceptibility of tuberculosis. However, the macrophages of smokers are exhausted from their daily exposure to smoke, making them unable to correctly function. This therefore means they are they are no longer able to respond to the challenge of killing infections.

Scientists at Trinity College Dublin and St James’s Hospital have compared the lung cells of those that smoke to those that do not in order to better understand how lung cell exhaustion and lung immunity against tuberculosis works. The researchers are working to design ways to support the human immune system to prevent this infectious disease arising in marginalised members of society.

The scientists have shown that lung macrophages can turn on helpful pathways of energy production after infection with TB bacteria. Using lung cells, they have now demonstrated that these energetic pathways can be engaged in the lung after bacterial infection. This can effectively control the bacteria after it has been inhaled from an infectious person with TB. The ability to switch metabolism appears to be a central process in host defence.

When the team looked at lung macrophages taken from individuals who smoke, they noticed that these smokers’ cells had distinctly reduced metabolic activity, and had no metabolic reserves to respond to the infection. This is a first description of smoker’s lung cells as an exhausted macrophage, and the investigators are now looking at ways to restore these helpful pathways to fortify immunity in cigarette smoking – to prevent infectious diseases.

Where can the research take us?

Research Fellow in Clinical Medicine at Trinity College Dublin, Dr Laura Gleeson, a recipient of the HRB health professional fellowship, commented on the significance of the finding: “Our new description of macrophage exhaustion in the lung might also lead to treatments that could be applied to other TB susceptible groups.

“These include persons who suffer from immunosuppressive conditions such as diabetes, HIV, and those taking immunosuppressive drugs”.

By gaining a better insight regarding the immunological processes which are damaged in the lungs of a smoker, scientists can also uncover ways to support the health of people suffering from lung cell exhaustion, therefore potentially avoiding not just infections but also lung cancer.