Aging and Bronchiolitis Obliterans Syndrome Linked to More Interalveolar Pores

Investigators found that aging and bronchiolitis obliterans syndrome are both associated with increased interalveolar communications.

Both typical aging and bronchiolitis obliterans syndrome were found to be significantly associated with increases in the number of interalveolar pores, according to the results of a recent study published in the American Journal of Respiratory and Critical Care Medicine.

An aging cohort of 20 lungs from donors who had never smoked were examined via electron microscopy to evaluate the size and number of interalveolar pores. The relationship of interalveolar pores with age was analyzed using univariate linear regression with Pearson correlation. The investigators then compared this aging cohort with 10 bronchiolitis obliterans syndrome (BOS) explant lungs using multivariate linear regression analysis, adjusted for the donor’s age and sex.

The investigators found a significant association between pore numbers and age but no association between aging and pore size. The study also revealed an approximately 3-fold increase in interalveolar pore numbers in BOS vs aging lungs but similar pore sizes. The sex of donors was not significantly associated with either pore numbers or size.

The study authors wrote, “Interalveolar pores are markedly increased in bronchiolitis obliterans syndrome.” They added that because more than 75% of small airways can become segmentally obstructed in end-stage BOS with a preserved number and diameter of terminal bronchioles, “collateral ventilation might form an important mechanism to prevent retro-obstructive alveolar collapse and maintain gas exchange.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 


Vanstapel A, Weynand B, Kaes J, et al. Interalveolar pores increase in aging and severe airway obstruction. Am J Respir Crit Care Med. Published online July 9, 2021. doi:10.1164/rccm.202102-0530LE