Consequences of exacerbation in old rats with emphysema - 08/04/25

Chronic Obstructive Pulmonary Disease (COPD), is marked by chronic airflow limitation due to small airway obstruction and emphysema, which involves abnormal enlargement of lung air spaces and inflammation-induced tissue destruction. COPD often coexists with cardiovascular diseases, likely due to chronic inflammation. As an age-related disease, COPD's effects are worsened with aging, intensifying both lung and systemic impacts. However, the connection between age-related emphysema and cardiac issues remains unclear, indicating a need for more research on how aging affects COPD's impact on cardiovascular health.

Old male Wistar rats (18 months old, n=9 control, 5 ELA-LPS) received weekly intra-tracheal instillations of elastase (ELA) over 4 weeks at a dose of 10U. I to induce emphysema. In the fourth week, alongside elastase, bacterial lipopolysaccharide (LPS) derived from E. coli O55 B: 5 was delivered to mimic a bacterial exacerbation. We evaluated pulmonary, cardiac and muscular functions using various in-vivo and ex-vivo methods, including cardiorespiratory tests on a treadmill, whole-body plethysmography and echocardiography. The results in aged animals were compared with those from young animals (6–7 weeks-old).

Preliminary results revealed significant alteration in cardiac systolic function, along by morphological changes in the left ventricular posterior wall during systole and diastole, compared to the young emphysema model, where a correlation between emphysema and diastolic dysfunction was noted. Unexpectedly, there was a trend of improvement in respiratory parameters, including Peak Inspiratory Flow, Peak Expiratory Flow, and tidal volume. The cardiorespiratory performance test showed a trend towards reduced O₂ consumption and decreased exercise capacity, consistent with aging patterns. Then, the assessment of lung elastic properties (ex vivo pressure-volume curve) indicated a greater loss of pulmonary elasticity compared to the young emphysematous model. Additionally, ex vivo endurance and force tests on the soleus muscle showed a tendency toward reduced muscle endurance and strength, aligning with the findings from the treadmill test.

This multidisciplinary approach seeks to deepen our understanding of the age-related aspects of COPD-emphysema and its broader impact on human health. Initial results are promising, showing that aged rats exhibit a more severe phenotype than younger ones. Once confirmed, the underlying causes of these age-related dysfunctions compared to younger animals need to be determined to provide valuable insights into associated cardiac disorders.