Effect of Hydroxytyrosol on Human Mesenchymal Stromal/Stem Cell Differentiation into Adipocytes and Osteoblasts

Background and AimsNatural phenolic compounds are known for their antioxidant capacity, showing biological activity in numerous physiological processes. Such chemicals have been proposed for prevention or treatment of pathologies like osteoporosis and diabetes. One of these is hydroxytyrosol (HT), which may be involved in the differentiation of human mesenchymal stromal/stem cells (MSCs), which are precursors of osteoblasts and adipocytes. Yet, little information is available. Therefore, our objective was to study the possible effect of HT on MSC differentiation.MethodsDifferentiation markers were analyzed while human bone marrow MSCs were differentiated into osteoblasts or adipocytes in the presence of 1 or 100 μmol HT.ResultsHigh HT concentrations repressed the expression of osteoblastic markers in MSCs differentiating into osteoblasts, whereas they increased the expression of adipogenic genes and the formation of fat vesicles in MSCs differentiating into adipocytes.ConclusionsHigh HT concentrations may inhibit osteoblastogenesis and promote adipogenesis, which can lead to bone loss. Therefore, the possible pharmacological use of extracts rich in HT should take into account this undesirable effect.