Mammary Stem Cell Research in Veterinary Science: An Update

Abstract

The mammary gland is an organ with a remarkable regenerative capacity that can undergo multiple cycles of proliferation, lactation, and involution. Growing evidence suggests that these changes are driven by the coordinated division and differentiation of mammary stem cell populations (MaSC). Whereas information regarding MaSC and their role in comparative mammary gland physiology is readily available in human and mice, such information remains scarce in most veterinary mammal species such as cows, horses, sheep, goats, pigs, and dogs. We believe that a better knowledge on the MaSC in these species will not only help to gain more insights into mammary gland (patho) physiology in veterinary medicine, but will also be of value for human medicine. Therefore, this review summarizes the current knowledge on stem cell isolation and characterization in different mammals of veterinary importance.

Conserved and variable: Understanding mammary stem cells across species

“…Among the diverse lactation properties are timing and length of lactation, milk quantity and composition, lactation of a single offspring or a litter, maternal nutrition during lactation, and timing and dynamics of mammary gland involution. Innumerable variations in lactation properties can be found among the thousands of mammalian species, with only some of these variations being the subject of scientific studies . Interestingly, MaSC are rarely considered or mentioned in these studies, despite their crucial role during lactation and following involution of the mammary gland.…”

Bovine CD49 positive-cell subpopulation remarkably increases in mammary epithelial cells that retain a stem-like phenotype

“…The symmetric division of stem cells produces two identical stem cells, resulting in the expansion of the stem cell population, whereas an asymmetric division will result in a new stem cell and a progenitor cell of a more committed lineage. These adult stem cells are generally considered long-lived, mostly quiescent, slow cycling cells that generate new stem cells, hereby maintaining the stem cell pool (Borena et al, 2013).…”

Bovine mammary gland development: new insights into the epithelial hierarchy

“…In many species, whether human, murine or bovine, the stem cell population, referred to as the MaSC 323 population, has been described as being CD49f high CD24 pos (Borena et al, 2013;Visvader and Stingl, 324 2014; Rauner et al, 2017). In our study, this cell sub-population represented 5.5% of total epithelial 325 cells or 3.8% of total mammary cells.…”