Effect of pregnancy on isolation efficiency and in vitro proliferation of equine peripheral-blood derived mesenchymal stromal cells.

Mesenchymal stromal cells (MSCs) have regenerative and immunomodulatory potential and may be used to treat injured tissues. Pregnancy has been associated with increased MSCs in the peripheral circulation in multiple species, but to date, there are no reports on this matter in horses. This study aimed to evaluate the effect of pregnancy on isolation efficiency and proliferation capacity of equine MSCs derived from the peripheral blood (PB) of mares. Venous blood samples were collected at the 11th month of gestation and 1 month after delivery from clinically healthy Arabian mares that presented normal pregnancies. Blood samples were processed for in vitro cellular culture and hormonal and metabolic profiles. MSCs were isolated and characterized by trilineage differentiation potential, immunophenotyping, analyzed by gene sequencing and proliferation assays. The isolation of peripheral blood mononuclear cells (PBMCs) of pregnant mares were associated with higher isolation efficiency and proliferative capacity of MSCs derived from peripheral blood (PB-MSCs) recovered pre-partum than those isolated post-partum. Although fetal gender, parity, 5α-reduced pregnanes, insulin, and cortisol were shown to affect cellular proliferation, individual factors and the small population studied must be considered. This study suggests that PB-MSCs from pregnant mares could be a valuable alternative source of MSCs for therapeutic purposes.

Equine Coronavirus-Associated Colitis in Horses: A Retrospective Study.

Equine coronavirus (ECoV) is a known cause of fever, anorexia, and lethargy in adult horses. Although there are multiple reports of ECoV outbreaks, less is known about the clinical presentation of individual horses during a nonoutbreak situation. The purpose of this study was to describe the clinical presentation of horses diagnosed with ECoV infection that were not associated with an outbreak. Medical records of all horses admitted to Washington State University, Veterinary Teaching Hospital, during an 8-year period were reviewed (2010-2018). The five horses included in this study were older than 1 year of age, were diagnosed with colitis, tested positive for ECoV using real-time polymerase chain reaction, and were negative to other enteric pathogens. Interestingly, 4 of 5 horses had moderate to severe diarrhea, 3 had abnormal large colon ultrasonography, 2 had transient ventricular tachycardia and 2 had clinicopathologic evidence of liver dysfunction. ECoV should be included as a differential diagnosis for individual horses presenting with anorexia, fever, lethargy, and colitis. Early identification of ECoV cases is key to implement appropriate biosecurity measures to prevent the potential spread of this disease.