Separation of equine bronchopulmonary lavage cells by density gradient centrifugation and expression of procoagulant activity in unpurified cells and cell subpopulations.

This research examined cells from horse lung washes in healthy and chronically diseased horses, to investigate the differences in cell types and to discover the source of Procoagulant activity (PCA). The study found that macrophages, a type of immune cell, were the prominent cells in healthy horses, while neutrophils, another immune cell type, were dominant in severely diseased horses. When testing for PCA, it was confirmed in all cells tested, with indications that the PCA discovered may be originating from macrophages.

Study Methods and Findings

The study involved bronchopulmonary lavage – a lung wash procedure – on a group of horses. Fifty percent of these horses were healthy, while the rest were suffering from chronic pulmonary disease.

• The researchers identified that macrophages were the predominant cell in healthy horses, whereas neutrophils were the predominant cell in horses with severe disease.
• Additionally, they found Procoagulant activity (PCA), a process related to blood clotting, in all of the samples they examined. This included all 32 cell-free supernatants and all 49 unpurified cell suspensions.

The cells were separated into different categories through a process called density gradient centrifugation. Macrophages were most commonly found in subpopulations of low density.

• Interestingly, they could not purify neutrophils using this type of centrifugation, an anomaly that requires further investigation.
• The researchers then plotted the PCAs of cell subpopulations against their respective macrophage, neutrophil, and lymphocyte content.

Key Findings

The study’s critical findings revolve around Procoagulant activity (PCA), which was found across all samples.

• The PCA levels were positively correlated with the presence of macrophages, showing a likely link between this type of immune cell and the PCA.
• Conversely, PCA was negatively correlated with the presence of neutrophils and lymphocytes (other types of immune cells). This indicates the possibility that these cells might inhibit PCA activity.

The conclusion suggested was that PCA from the lungs of horses, much like in other species, is primarily originating from macrophages. The inability to purify neutrophils by the same method clarifies the need for further study on this subject.