Chapter 32 - Mast Cells in Myocardial Ischaemia and Reperfusion

Abstract

This chapter summarizes information derived from in vivo and in vitro experiments on the potential role of mast cells in initiating the cytokine cascade associated with myocardial ischaemia and reperfusion. A general description of the resident mast cell population in the normal heart is provided and the potential role of mast cells as a source of cytokines in the ischaemic myocardium is analyzed. The role of mast cells and their products in the healing process is also examined. Mast cells have been recognized as an important source of pre-formed and newly synthesized cytokines, chemokines and growth factors. They also play an important role in initiating the cytokine cascade ultimately responsible for intercellular adhesion molecule-1 (ICAM-1) induction in the reperfused canine myocardium. Stem cell factor (SCF) is a potent mast cell chemoattractant that stimulates directional motility of both mucosal and connective tissue-type mast cells. In addition, several angiogenic factors, such as platelet-derived growth factor (PDGF) AB, VEGF (vascular endothelial growth factor) and bFGF (basic fibroblast growth factor) have been demonstrated to promote murine mast cell chemotaxis in vitro. When activated mast cells were co-cultured with fibroblasts they were found to increase collagen synthesis and stimulate fibroblast proliferation, indicating a direct involvement of mast cells in the fibrotic process. Mast cells may influence healing and tissue remodelling by expressing gelatinases A and B, which are implicated in extracellular matrix degradation and angiogenesis.