The Effects of Insulin Like Growth Factor -1 (IGF-1) on the Plasticity of Umbilical Cord Blood Derived Mesenchymal Stem Cells Colonies to In Vitro Neurogenic Differentiation

Abstract

Umbilical cord blood derived mesenchymal stem cells (UCB-MSCs) are pluripotent, easily expanded in culture, and has been much interest in their clinical potential for tissue repair and gene therapy. This study was performed to investigate the possibility of obtaining clonally expanded culture of MSCs derived from human UCB then studying the effect of Insulin like growth factor-1 (IGF-I) on the plasticity of MSCs colonies to their in vitro neurogenic differentiation and determining the differentiation pathway using neural marker (nestin). The mononuclear cells (MNCs) were obtained from cord blood after gradient density centrifugation, these cells were cultivated in a culture medium Iscove's Modified Dulbecco's Medium (IMDM)  supplemented with 10% Fetal bovine serum (FBS), then incubated at 37°C and 5% CO₂ for three weeks. In most cases, the cultures of plastic-adherent cells proved to be heterogonous. Both spindle-shaped and round cells were observed. Immunophenotypically, the MSCs were found to be positive for CD71 and negative for CD34. These results indicated that MSCs are not hematopoietic in origin. These cells after passage retained their fibroblast –like morphology. Regardless to the concentration of IGF-I, this growth factor stimulates the differentiation of MSCs –toward the neuronal pathway. So, the MSCs colonies showed the ability to maintain their plasticity to form the specialized cells (neuronal like cells) after treated with IGF-I even in culturing for long time and these cells stained positively to the nestin marker. In conclusion: the IGF-I promoted and maintained the plasticity of UCB-derived MSCs and their colonies to differentiate into neuronal-like cells.

Key words: Mesenchymal stem cells, Umbilical cord blood, Nestin, Neurogenic differentiation, Insulin like growth factor-1.