Cytokines produced by bone marrow cells can contribute to functional improvement of the infarcted heart by protecting cardiomyocytes from ischemic injury.
It is well known that the implantation of bone marrow mononuclear cells (BM-MNCs) into ischemic hearts can induce angiogenesis and improve cardiac function after myocardial infarction, but the precise mechanisms of these actions are unclear. We hypothesize that the cytokines produced by BM-MNCs play a key role in this cell-based therapy. BM-MNCs from rats were cultured under normoxic or hypoxic (1% O2) conditions for 24 h, and then supernatants were collected for study. ELISA and Western blotting analysis showed that various cytokines, including VEGF, IL-1 beta, PDGF, and IGF-1, were produced from BM-MNCs, some of which were enhanced significantly under hypoxia stimulation. When compared with a control blank medium, the supernatants of BM-MNCs cultured under normoxic or hypoxic conditions inhibited apoptosis significantly and preserved the contractile capacity of isolated adult rat cardiomyocytes in vitro (P < 0.05). Using a rat model of acute myocardial infarction, we injected the supernatants of BM-MNCs or control medium intramyocardially on day 0 and then intraperitoneally on days 2, 4, and 6 after infarction. When compared with the control medium, the supernatants of BM-MNCs cultured under both normoxic or hypoxic conditions increased the microvessel density and decreased the fibrotic area in the infarcted myocardium significantly, contributing to remarkable improvement in cardiac function. Various cytokines were produced by BM-MNCs, and these cytokines contributed to functional improvement of the infarcted heart by directly preserving the contractile capacity of the myocardium, inhibiting apoptosis of cardiomyocytes, and inducing therapeutic angiogenesis of the infarcted heart.
Takahashi
Masaya
M
Department of Medical Bioregulation, Division of Cardiovascular Surgery and Medicine, Yamaguchi University School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi 755-8505, Japan.
Li
Tao-Sheng
TS
Suzuki
Ryo
R
Kobayashi
Toshiro
T
Ito
Hiroshi
H
Ikeda
Yasuhiro
Y
Matsuzaki
Masunori
M
Hamano
Kimikazu
K
D000208:Acute Disease; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology; D015687:Cell Hypoxia / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis* / Q000502:physiology*; D004452:Echocardiography; D042783:Endothelial Cells / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000473:pathology*; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000473:pathology*; D018919:Neovascularization, Physiologic / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
D016207:Cytokines