Immunomodulatory properties of MSCs

Abstract

Mesenchymal stromal cells (MSCs) are multipotent cells that can be isolated from several human tissues and expanded ex vivo for clinical use. They comprise a heterogeneous population of cells, which, through production of growth factors, cell-to-cell interactions and secretion of matrix proteins, play a key role in the regulation of haematopoiesis. In recent years, several experimental studies have shown that MSCs are endowed with potent immunomodulatory properties directed in vitro at all cells involved in immune responses. Due to their immunomodulatory and engraftment-promoting properties, MSCs have been tested in the clinical setting both to facilitate haematopoietic engraftment and to treat steroid-resistant acute graft-versus-host disease (GvHD). More recently, experimental findings and clinical trials have focused on the ability of MSCs to home to injured tissues and to produce paracrine factors with anti-inflammatory properties, resulting in functional recovery of damaged tissues. The mechanisms through which MSCs exert this pleomorphic therapeutic potential rely on some key properties of these cells: The capacity to home to sites of injury, the ability to blunt exaggerated immune responses and the ability to secrete soluble factors capable of stimulating both the survival and recovery of injured cells. This chapter focuses on recent advances in MSC biology and summarises the clinical studies on their immunomodulatory and anti-inflammatory properties, particularly in the setting of allo- and autoimmune disorders.