Clinical Impact of Radiation-Resistant Mesenchymal Stem Cells in Bone Marrow Deduced from Preclinical Studies

Yuichi Michikawa

doi:10.4172/2329-8820.1000101

Abstract

Mesenchymal stem cells in the bone marrow have attracted great interest over the past decades, not only as a basic scientific subject but also as a novel and advanced clinical tool. More than 100 mesenchymal stem cell-related clinical trials are currently registered in the world. Hematopoietic stem cells in bone marrow are extremely radiationsensitive, whereas mesenchymal stem cells show considerable radiation-resistance. Intrinsic cellular mechanisms, including highly efficient reactive oxygen species-scavenging ability and active DNA damage response pathways, have been reported to explain the radiation-resistance of mesenchymal stem cells in the bone marrow. The precise interactions between residual host mesenchymal stem cells and donor mesenchymal stem cells at the time of bone marrow transplantation following whole-body irradiation, however, remain unknown. This short review summarizes our current understanding of the clinical impact of the radiation-resistance of endogenous mesenchymal stem cells in the bone marrow.

Highlights

Human bone marrow contains at least two distinct types of stem cells [1] in terms of sensitivity to radiation
Exposure of bone marrow to radiation leads to the rapid depletion of radio-sensitive Hematopoietic Stem Cells (HSCs) and their progenitors, and hematopoietic failure presenting with pancytopenia [3]
Because Mesenchymal Stem Cells (MSCs) are present as minor components in transplanted bone marrow cells, donor MSCs are likely to meet and interact with the host MSCs in the patient’s bone marrow, as illustrated in figure 1. This short review focuses on our current understanding of the biologic relevance of radiation resistance of host MSCs in bone marrow based on the clinical outcome, while pointing out unresolved questions to facilitate further research in this field