Effects of low temperature and lactate on osteogenic differentiation of human amniotic mesenchymal stem cells

A functional relationship between the growth and the progression of events associated with osteogenic differentiation of human amniotic mesenchymal stem cells (hAMSCs) has been a fundamental question, which remains unclear. This study is aimed at investigating the effects of low temperature and lactate individually, and in combination on the growth and osteogenic differentiation of hAMSCs. It was shown that the growth of hAMSCs in growth medium was inhibited by both low-cultivation temperature and lactate. By extending culture period at low temperature, cell growth declined gradually, while the ALP expression and calcium deposition increased progressively. However, the growth of hAMSCs induced in osteogenic medium at 37°C was markedly enhanced by additional lactate. The ALP expression and calcium deposition, on the contrary, were significantly depressed. Furthermore, the synergistic actions of long-term low temperature and lactate resulted in more intense inhibition on both cell growth and osteogenic differentiation. Therefore, these findings may imply the co-contribution of the culture environment on the selective manipulation on the growth capacity and osteogenic differentiation potential of hAMSCs.