Heaves. Broken wind. Recurrent airway obstruction (RAO). All names for an respiratory condition in horses characterized by airway hyper-reactivity and bronchospasm. It’s typically seen in older horses who are chronically exposed to dust – including dusty hay. If it sounds familiar, it should – it’s very similar to asthma in humans. In humans, the mechanism of normal programmed cell death (“apoptosis” is the medical term) of inflammatory cells is disrupted, which leads to all sorts of bad things like tumors, autoimmune disease, and chronic pulmonary obstructive disease (COPD). It’s believed that disruption of the normal cell death process of inflammatory cells is involved in equine RAO, too.
Researchers in Poland wanted to know what role this abnormal cell death plays in equine RAO. They studied two groups of horses – one group with RAO, one without. In their analysis of cells obtained by bronchial wash, they found that the RAO horses had abnormal cell death of neutrophil, macrophages, and other inflammatory cells, but the non-RAO control horses did not.
While this study had a small sample size, it demonstrated some very important aspects of how respiratory disease causes damage that warrant further investigation. Since the mechanism of equine RAO and human COPD/asthma are similar, these findings are an important step toward finding therapeutic solutions to this type of respiratory disease for both of us!