Equine Colostrum-Derived Mesenchymal Stromal Cells: A Potential Resource for Veterinary Regenerative Medicine

Beyond its immunological role, colostrum has emerged as a promising, non-invasive source of bioactive factors, including mesenchymal stem/stromal cells (MSCs). This study represents the first attempt to isolate and characterize MSCs from equine colostrum (C-MSCs) to assess their potential use in veterinary regenerative medicine. Colostrum (n = 6) was collected from mares immediately after their delivery and centrifuged, and the recovered cells were cultured under standard conditions. The C-MSCs displayed plastic adherence and a heterogeneous morphology, including spindle-shaped and epithelial-like cells. The population doubling time (PDT) values varied among the samples, and four out of six showed rapid proliferation (<2 days). Colony-forming unit (CFU) assays confirmed their clonogenic potential, though significant inter-sample variability was observed (p < 0.05). Spheroid formation assays revealed differences in cell-cell adhesion: four out of six samples formed stable spheroids within four days. A migration assay showed significant variability (p < 0.05): one out of six achieved complete wound closure within 72 h, whereas five out of six reached ~30% at 96 h. All samples were positive for adipogenic, chondrogenic, and osteogenic differentiation as shown via staining. RT-PCR confirmed MSC marker expression, while hematopoietic markers were absent. MHC-I expression was weak in five out of six samples, whereas MHC-II was consistently negative. These findings support equine colostrum as a viable MSC source, though its variability requires further validation with larger samples. Additional research is needed to investigate C-MSCs' immunomodulatory properties and therapeutic potential.