Low-density lipoprotein (LDL) uptake demonstrates a hepatocyte phenotype in the dog but is non-specific

Low-density lipoprotein (LDL) uptake is one of a number of tests used to demonstrate hepatocyte-like function after stem cell differentiation. Use of two compounds; LDL and acetylated LDL has been described despite each having different mechanisms of uptake. Three primary hepatocyte cultures and three sets of mesenchymal stromal cell (MSCs) cultures, derived from both adipose tissue and bone marrow, were harvested from dogs. Those cells were compared to commercially available human and mouse bone marrow derived MSCs. LDL receptor expression was demonstrated by gene expression and immunofluorescence in all primary hepatocyte cultures, undifferentiated canine bone marrow mesenchymal stromal cells (MSCs) and canine adipose MSCs. Undifferentiated human and mouse bone marrow MSCs also expressed the LDL receptor. In vitro, canine hepatocytes took up labelled LDL but not acetylated LDL. All undifferentiated MSCs took up LDL but not acetylated LDL. In conclusion, LDL and not acetylated LDL is a test of canine hepatocyte-like phenotype but this is not tissue or species specific and therefore is not informative assay when testing proof of MSC to hepatocyte differentiation.