Secretoglobin and Transferrin Expression in Bronchoalveolar Lavage Fluid of Horses with Chronic Respiratory Disease

Abstract

BackgroundLower expression of secretoglobin and transferrin has been found in the bronchoalveolar lavage fluid (BALF) of a small number of horses with experimentally induced signs of recurrent airway obstruction (RAO) compared to healthy controls.Hypothesis/ObjectivesSecretoglobin and transferrin BALF expression will be similarly decreased in horses with naturally occurring clinical signs of RAO and in horses with experimentally induced clinical signs of RAO as compared to healthy controls and intermediate in horses with inflammatory airway disease (IAD).AnimalsRecurrent airway obstruction‐affected and control horses were subjected to an experimental hay exposure trial to induce signs of RAO. Client‐owned horses with a presumptive diagnosis of RAO and controls from the same stable environments were recruited.MethodsPulmonary function and BALF were evaluated from control and RAO‐affected research horses during an experimental hay exposure trial (n = 5 in each group) and from client‐owned horses (RAO‐affected horses, n = 17; IAD‐affected horses, n = 19; healthy controls, n = 5). The concentrations of secretoglobin and transferrin in BALF were assessed using Western blots.ResultsNaturally occurring and experimentally induced RAO horses had similar decreases in BALF transferrin expression, but secretoglobin expression was most decreased in naturally occurring RAO. Secretoglobin and transferrin expression were both lower in BALF of RAO‐affected horses than in IAD‐affected and control horses.Conclusions and Clinical ImportanceSecretoglobin and transferrin expression is decreased in BALF of RAO‐affected horses after both experimental and natural exposure. Secretoglobin and transferrin likely play clinically relevant roles in the pathophysiology of RAO, and may thus be used as biomarkers of the disease.

Investigation of blood biomarkers for the diagnosis of mild to moderate asthma in horses

“…This protein represents a major constituent of airway surface fluid . In previous reports, BALF SCGB expression was significantly decreased in severely asthmatic horses, as well as in humans with asthma, when compared to healthy controls. We had postulated that combining biomarkers that are both increased and decreased in the blood of asthmatic horses would increase the sensitivity and specificity for diagnosis.…”

Acute-phase protein concentration in bronchoalveolar lavage fluid from healthy horses

“…Transferrin concentrations may change with the duration and severity of inflammation, and thus the discrepancy in results between studies is not surprising. These differences suggest that secretoglobin and transferrin may be useful as biomarkers or as possible treatment targets for RAO (Miskovic Feutz et al 2015).…”

“…Plasma exudation occurs independent of cellular diapedesis and migration and is not necessarily observed in all types of pulmonary inflammatory diseases (Persson 1991). Secretoglobin expression in BALF was significantly higher in horses with recurrent airway obstruction (RAO) compared to that in the control horses and inflammatory airway disease-affected horses (Miskovic Feutz et al 2015). Secretoglobin is an anti-inflammatory protein that inactivates phospholipase A2, decreases proinflammatory cytokine production, alters phagocyte function, and may decrease the inflammatory response to endotoxin (Snyder et al 2010).…”