Isolated airways in equine respiratory pharmacology: They never lie.

The research investigates if data from equine isolated airways have any application in treating asthmatic horses. This comprehensive study combines findings from different bronchodilators and evaluates their impact on the respiratory function of horses with asthma, suggesting that pre-clinical investigations using equine isolated airways can be useful.

Background and Aim

• This research is focused on understanding and evaluating the translational value of studies performed on isolated airways in horses, specifically as it applies to the treatment of asthmatic horses.
• The goal is to assess how the pharmacological characteristics of bronchodilators, extracted from studies, directly affect the lung functions outcomes in asthmatic horses. It raises the question of whether these ‘in vitro’ studies provide useful data in predicting how these bronchodilators would perform ‘in vivo’.

Methodology

• The researchers used a meta-regression analysis via a random-effect method to correlate results from in vitro studies with in vivo results. This is a statistical model used to analyze the relationships between study data and the effects of different conditions or treatments.
• Data regarding the potency of distinct bronchodilators were extracted from four ex vivo studies involving 68 horses. These data were then connected to parameters including changes in the transpulmonary pressure, pulmonary resistance, and dynamic lung compliance.

Findings

• The potency of each bronchodilator, as detected in equine isolated bronchi, did not significantly influence the bronchodilatory effect seen in clinical trials.
• The pulmonary resistance had a flatter line of meta-regression compared to pulmonary pressure and dynamic lung compliance. This could potentially mean that the bronchodilators’ effect on resistance was relatively consistent regardless of their observed in vitro potency.
• The quality of evidence was termed moderate for pulmonary resistance and pressure change while low for lung compliance. This indicates the need for further confirmatory studies.

Conclusion

• The findings suggest that pre-clinical investigations carried out using equine isolated airways can produce useful data for predicting the bronchodilators’ impact on the pulmonary resistance of asthmatic horses.
• However, further translational studies are required to confirm the results of this research due to the varying quality of evidence.