Lipidomic analysis of surfactant and plasma from horses with asthma and age-matched healthy horses.

The research paper is about the comparison of surfactant and plasma lipidomic profiles from horses with asthma and their healthy counterparts to identify possible implications for asthma diagnosis, prognosis, and treatment in horses. The researchers found that surfactant alterations were most significant in severe equine asthma and mild changes were observed in mild equine asthma with neutrophilic airway inflammation, while the plasma lipidomic profile was significantly altered in all asthmatic horses.

Study Method

• The study involved 30 asthmatic horses and 30 healthy horses matched by age.
• A detailed history and physical examination of each horse were taken, along with a complete blood count (CBC).
• They also verified the horses’ bronchoalveolar lavage fluid (BALF) cytologies, which are examinations of cells that reside within or are retrieved from the lower respiratory tract of horses.
• The asthmatic horses were grouped as severe equine asthma (SEA), mild equine asthma with neutrophilic airway inflammation (MEA-N), or mild equine asthma with eosinophilic airway inflammation (MEA-E). Each of these asthma groups were also assigned an age-matched healthy control group.
• The researchers then conducted lipidomic analyses on the surfactants and plasma of these groups.
• The concentration of Surfactant protein D (SP-D), a substance involved in lung health, was also measured in their serum and BALF.

Study Findings

• The SEA surfactant was found to have a phospholipid deficit and a distinct composition characterized by increased ceramides, decreased phosphatidylglycerol, and increased cyclic phosphatidic acid (cPA).
• The MEA-N surfactant exhibited a decrease in specific phosphatidylglycerol species and increased cPA levels.
• Notably different lipidomic profiles were observed in the plasma of all asthmatic horses as compared to the controls.
• All groups of asthmatic horses exhibited an increase in plasma phytoceramide. SEA horses also showed an increase in plasma cPA and diacylglycerol (a type of fat), while MEA-N horses only had increased cPA. Meanwhile, MEA-E horses showed increases in certain ceramides and dihydrocermides (a type of sphingolipid).
• Increased serum SP-D concentrations were present only in SEA horses.

Conclusions

• The study highlighted notable alterations in the surfactant in cases of severe equine asthma, with only mild differences observed in horses with mild equine asthma and neutrophilic airway inflammation.
• All asthmatic horse groups had significantly different plasma lipidomic profiles.
• The authors suggest further studies with larger asthmatic horse populations for a more comprehensive understanding of the implications of these findings for diagnosis, prognosis as well as the treatment of equine asthma.