chapter  4
30 Pages

Stem Cell Physiological Responses to Noninvasive Electrical Stimulation

Introduction: Stem Cell Types ............................................................................ 92 Control of Stem Cell Behavior by Electrical Stimulation................................... 93 Calcium Dynamics and Stem Cells Differentiation Regulation by Electrical Stimulation .......................................................................................... 94

Calcium Dynamics ......................................................................................... 94 The Regulation of Ca2+ Oscillations .............................................................. 95

Control of Ca2+ Dynamics by Electrical Stimulation .......................................... 97 Regulation of Differentiation ......................................................................... 97 Regulation of Ca2+ Oscillations ...................................................................... 97 The Role of Ion Channels .............................................................................. 99 The Role of Phospholipase C ......................................................................... 99 The Role of Integrins ................................................................................... 100 The Role of ATP ........................................................................................... 100 Summary of Electrocoupling Mechanisms ...................................................101

Control of Stem Cell Mechanics by Noninvasive Electric Field .......................101 Regulation of Cell Elasticity by Electrical Stimulation ............................... 102 The Actin Cytoskeleton ................................................................................ 103 The Effect of Electrical Stimulation on the Actin Cytoskeleton .................. 105 The Combined Effect of Growth Factors and Electrical Stimulation .......... 105 Membrane-Cytoskeleton Coupling .............................................................. 106 The Role of Electrical Stimulation in Membrane-Cytoskeleton Coupling ... 107 Summary ...................................................................................................... 108

Stem cells are distinct unspecialized cells with unique features found in most multicellular organisms. They are characterized by the ability to renew themselves and to differentiate into a diverse range of specialized cell types (Cedar 2006; Moore and Lemischka 2006). The most known types of mammalian stem cells are embryonic stem cells, adult stem cells, and induced pluripotent stem cells (Jaishankar and Vrana 2009; Kao et al. 2008). Embryonic stem cells (ESCs), isolated from the inner cell mass of blastocysts, are pluripotent, meaning they can become virtually any cell in the body, and can conceivably be grown and differentiated into replacement cells for therapeutic need (Grivennikov 2008; Jensen 2009). However, the seemingly unlimited therapeutic potential associated with human ESCs is tempered with safety (e.g., teratoma formation), legal, and ethical issues (Mertes and Pennings 2009).