A study published in the Journal of the Royal Society Interface reports that smoking stiffens human lung tissue in a manner similar to fibrosis.
Key Findings
- Researchers at UC Riverside, led by mechanical engineer Mona Eskandari, conducted tensile tests on human lung parenchyma tissue from donors.
- Tissue from smokers was significantly stiffer and resisted expansion more strongly compared to non-smokers.
- The study tested tissue by stretching in multiple directions simultaneously, mimicking natural breathing, unlike prior studies that used single-axis stretching or animal models.
- Lung tissue showed mechanical nonuniformity: upper regions were generally stiffer than lower regions, possibly due to gravitational forces in upright humans.
- Human lung tissue dissipated more energy during repeated stretching cycles than typically observed in mice, suggesting animal models may not fully represent human lung mechanics.
- Preliminary trends indicate age-related stiffening, but researchers note limited donor samples restrict definitive conclusions.
Implications
- The findings may explain why ventilator-induced lung injury does not spread evenly, as some regions are more vulnerable to overstretching.
- The data can improve computational "digital twin" lung models, ventilation strategies, and surgical planning tools, especially when based on human rather than animal data.
"We are trying to understand the biological materials we are working with. If we want ventilators and predictive tools that truly reflect how people breathe, these technological advances need to be informed by human-based lung data."
— Mona Eskandari, UC Riverside