Canine colostrum exosomes: Characterization and influence on the canine mesenchymal stem cell secretory profile and fibroblast anti-oxidative capacity [post]

2020 unpublished
metabolism and vital functions of the neonate [2] [3] [4] [5] [6] [7] [8] . This secretion contains many described components (immunoglobulins, proteins or fat) and different biological membrane structures that transport bioactive molecules (cargo) related to signalling pathways and intercellular communication with newborn tissues [8, 9] . Among these vesicular structures, exosomes stand out. Exosomes are biological nanovesicles (30-200 nm) composed of a lipid bilayer and secreted by different
more » ... reted by different cell types, whose cargo includes proteins, lipids and nucleic acids (mainly miRNA) [6, 10]. Because of their membrane, exosomes in breast milk can survive harsh conditions, such as digestion, and are absorbed intact by intestinal epithelial cells [11] [12] [13] [14] and incorporated into the circulatory system by endocytosis through vascular endothelial cells [15] . Breast milk exosomes are involved in the regulation of the neonate´s immune response, promoting the growth of the intestinal epithelium and microbiota development [16] [17] [18] . Exosomes have been described in human breast milk and some domestic species, such as pig, cow, horse, buffalo, yak and camel [19] [20] [21] [22] [23] [24] [25] [26] . Although exosomes have been isolated from different cell types in canine species [27] [28] [29] , they have not been described in CCM. The effect of CCM exosomes has been evaluated in some cell types [30] ; however, it has never been assessed in mesenchymal stem cells (MSCs). MSCs play a strategic role in the development, homeostasis and repair of different organs and tissues [31, 32] and have shown promising results in the treatment of different canine pathologies [33, 34] . Therefore, we believe that it is interesting to demonstrate the effect of canine colostrum exosomes on different types of MSCs to help understand their role in the neonatal period in the canine species. On the other hand, in the early stages of life after birth, there is an exponential increase in reactive oxygen species (ROS) [35] , which may be responsible for serious alterations that are very well described in the human neonate [36, 37] , calves [38] and canine newborns [35] . Among the components of colostrum, there are different essential antioxidants against oxidative damage [38, 39] ; however, the antioxidant potential of CCM exosomes has not been evaluated. With these premises, the purpose of our study was, for the first time, to isolate exosomes by ultracentrifugation from CCM and characterize them according to transmission electron microscopy
doi:10.21203/rs.2.15189/v4 fatcat:ibgve7g22ncr7duqpn4h7u723i