A New View of Cigarette Smoke’s Effect on Lungs’ Blood Vessels in Healthy Adults

It’s no longer controversial that cigarette smoke exposure contributes to a long list of lung diseases; however, its pulmonary vascular effects have not been well studied in the general population, largely due to technological constraints. Now researchers at Beth Israel Deaconess Medical Center (BIDMC) have used computed tomography (CT) imaging technology to visualize the effects of tobacco exposure on pulmonary blood vessels in healthy individuals. Their surprising findings raise questions concerning how best to assess lung health.

“Our study is among the first to use CT imaging to study cigarette smoke-related changes in a large and generally healthy population,” said lead author Andrew Synn, MD, a senior fellow in the Division of Pulmonary, Critical Care and Sleep Medicine at BIDMC. For the study, published in the Annals of the American Thoracic Society, Synn and colleagues examined the smoking history and demographics of 2,410 adult participants of the long-running Framingham Heart Study Offspring and Third Generation Cohorts. The study subjects were by and large non-smokers (with nearly half never smoking, 44 percent former smokers and seven percent current smokers) with a low burden of lung disease who underwent whole-lung CT testing as part of the study from 2008 to 2011.

“Based on prior studies involving animal models, we expected that smokers would have smaller blood vessel volumes; however, the results of our study indicated the opposite,” Synn explained. “We found that individuals exposed to cigarette smoke – including active smokers, former smokers, and those with second-hand smoke exposure – had larger pulmonary blood vessels compared with non-smokers, especially in the smallest and most distal vessels in the lung.”

The unexpected results provide new information on how cigarette smoke affects the pulmonary vessels, and they indicate that the appearance of vessel changes under the microscope can be different from their appearance in radiographic images in humans. “This is an important consideration given that CT scans are increasingly used to study this type of disease,” Synn noted. 

The investigators noted that although the study results will not directly affect current clinical practice, they may support the use of CT scan techniques to identify individuals with abnormal changes in pulmonary vessels, including alterations caused by cigarette smoking. 

“We are actively continuing our research using CT scans to determine how changes in the pulmonary blood vessels affect lung health,” Synn said. “We are also planning to apply our research method to CT scans at BIDMC, with the long-term goal of helping patients and doctors predict who is at risk for pulmonary blood vessel complications, especially in the setting of chronic obstructive pulmonary disease and other chronic lung diseases.” 

In addition to Synn, authors include Chunyi Zhang and Mary B. Rice of BIDMC; George R. Washko and Raúl San José Estépar of Brigham and Women’s Hospital; George T. O’Connor of Boston University; and Wenyuan Li and Murray A. Mittleman of the Harvard T. H. Chan School of Public Health.

This work was supported by National Institutes of Health (NIH) grants R01 HL122464 and R01 HL116473 (G.R.W.), and 1R01 HL116931 and R01 HL116473 (R.S.J.E.), National Institute for Environmental Health Sciences grant K23 ES026204, the American Thoracic Society Foundation, and the American Lung Association (M.B.R.), and in part by National Heart, Lung and Blood Institute Framingham Heart Study contracts N01-HC-25195 and HHSN268201500001I.