Submitted on July 23, 2007
Accepted on December 10, 2007
Hypoxic preconditioning increases the survival and angiogenic potency of peripheral blood mononuclear cells via oxidative stress resistance
Masayuki Kubo1, Tao-Sheng Li2, Ryo Suzuki2, Bungo Shirasawa2, Noriyasu Morikage2, Mako Ohshima2, Shu-Lan Qin2, and Kimikazu Hamano3*
1 Department of Surgery and Clinical Science, Yamaguchi University, Graduate School of Medicine, Ube, Yamaguchi, Japan
2 Department of Surgery and Clinical Science, Yamaguchi University, Graduate School of Medicine, Ube, Japan
3 Department of Surgery and Clinical Science, Yamaguchi University, Graduate School of Medicine, Ube, yamaguchi, Japan
* To whom correspondence should be addressed. E-mail: kimikazu{at}yamaguchi-u.ac.jp.
Cell-based angiogenesis is a promising treatment for ischemic diseases; however, the survival of implanted cells is impaired by oxidative stress in the ischemic microenvironment. We tested the hypothesis that hypoxic preconditioning of implanted cells enhances their resistance against oxidative stress, increasing cell survival and angiogenic potency after implantation into ischemic tissue. Mouse peripheral blood mononuclear cells (PBMNCs) were collected, and subjected to hypoxic preconditioning by culture for 24 h in 2% O2 at 33°C. Hypoxic preconditioning of PBMNCs increased the expression of various genes related to antioxidant and survival signals, remarkably. Compared with cells cultured under normoxia, the hypoxia-preconditioned PBMNCs showed significantly lower reactive oxygen species (ROS) accumulation and higher cell survival under oxidative stress induced by LY83583 (a superoxide generator). Three days after intramuscular implantation into the ischemic hindlimbs of mice, survival of the hypoxia-preconditioned PBMNCs was high, whereas that of the normoxia-cultured PBMNCs was relatively low. Furthermore, 28 days after treatment, the microvessel density and blood flow in the ischemic hindlimbs were significantly better in the mice implanted with hypoxia-preconditioned PBMNCs than in those implanted with normoxia-cultured PBMNCs. Hypoxic preconditioning increased the survival and angiogenic potency of PBMNCs, through oxidative stress resistance mechanisms.
