Scientific Journal of

  Abstract

 Background and Objectives

 Bone marrow microenviroment contains cellular and acellular compartments. Cellular compartment contains hematopoetic stem cells, mesenchymal stem cells and some other kinds of stromal cells while acellular compartment includes scaffold proteins known as an extra cellular matrix. Hematopoietic stem cells resided in the bone marrow interact with a bone marrow microenvironment called the stem cell niche. Hematopoietic stem cells (HSCs) are able to produce the variety of blood cells and bone marrow microenvironment plays a supportive role for the cells in this process. Recent studies over in-vitro models demonstrating the essential role of stromal cells in hematopoiesis reflected the view that cell-cell contact in the marrow microenvironment is critical for hematopoietic stem cells normal function and differentiation. Direct cell-cell contacts and cytokines secreted by mesenchymal stem cells play a critical role in the coculture of hematopoetic stem cells and mesenchymal stem cells and the determination of the fate of hematopoetic stem cells. Several studies demonstrate the effect of mesenchymal stem cells on self renewal, expansion, proliferation and differentiation of hematopoetic stem cells in vitro that lead to different and contradictory results. In this paper, we will investigate the effect of mesenchymal stem cells on differentiation of hematopoietic stem cells in vitro.

 Materials and Methods

 The data of the present article were obtained through the review of many papers published on the effect of stem cells.

 Results

 The review of different studies has shown the necessity to survey the effect of mesenchymal stem cells on differentiation of different cell lines as a laboratory model.

 Conclusions

 Direct cell-cell contact between mesenchymal stem cells and hematopoietic stem cells and the signaling pathways activated by this interaction enable proliferation and expansion of HSCs in the undifferentiated state.