Patients with chronic obstructive pulmonary disease (COPD) often display inhibited mitochondrial protein pathways, according to a study published in the Journal of Clinical Investigation.

Researchers from Brown University examined healthy patients’ and smoking patients’ lung samples in order to demonstrate that the expression of the pathways in immune responses is decreased in COPD patients. The researchers examined the relationship between NLRX1, the protein known to inhibit the MAVS/ RIG-1-like helicase pathway, in the clinical stage of current and former smokers with COPD.

The team found that measured levels of the protein are a sign of cigarette induced emphysema, similar to the lung destruction that is seen in patients with COPD.