Biomedical Engineering Reference
In-Depth Information
oxygen and nutrients to cardiac cells, including cardiomyocytes and
fibroblasts.
Heart disease is the leading major cause of morbidity and
mortality, especially in industrialized countries [6-8]. Infarction
of
the coronary artery, which is caused by several reasons, leads to the
necrosis and loss of cardiac cells due to poor oxygen and nutrient
supply. The myocardial necrosis progresses sequentially ischemic
heart disease, which is found to show a phenomenon known as
negative cardiac tissue remodeling, which is (1) left ventricular wall
thinning in the infarction area, (2) ventricular chamber dilatation, (3)
compensatory hypertrophy of the noninfarcted portion of the heart,
and (4) heart tissue fibrosis [9, 10]. The remodeling decreases heart
function and may induce lethal heart disease and arrhythmia [11,
12]. Dilated cardiomyopathy (DCM) is a heart disease characterized
by ventricular (sometimes atrial) dilation, with reduced wall
thickness, and finally leads to varying degrees of impaired systolic
function [13, 14]. It is thought that DCM is caused by several reasons,
namely, (1) electrolyte abnormality, (2) endocrine abnormality, (3)
hypertension, (4) infection, and (5) ischemia, and familial DCM is
also known [15]. Inhibition and/or improvement of the negative
remodeling induces the improvement of cardiac performances. The
following therapies for curing heart disease, including ischemic heart
disease and DCM, have
been performed clinically: (1) drug therapy
(cardiac unloading by antihypertension, anticardiac remodeling,
antiarrhythmia, etc.), (2) surgical therapy (coronary artery bypass
graft surgery, surgical ventricular restoration, heart transplantation,
etc.), (3) catheter-based therapy (balloon catheter, stent placement,
ablation, etc.), and (4) medical device-based therapy (ventricular
assist devices, cardiac pacemaker, etc.) [16-34]. Although these
therapies markedly increase the survival rate of various patients, the
mortality still remains high at present. Some therapies have several
problems, namely, side effects (adverse effects), the necessity of
special techniques, repeated therapy, immune rejection, donor
shortage, infection, thrombi, etc. Many investigators have been
making untiring efforts to solve the problems.
Conventional therapies cannot restore the damaged myocardium,
and at present, there is no therapy for patients with severe heart
disease, other than heart transplantation. Recently, regenerative
therapy has attracted increasing attention as an alternative therapy
for heart transplantation (Fig. 1.1). Cytokine therapy for repairing
