Although endothelial progenitor cells (EPCs) have been used to promote revascularization after peripheral or myocardial ischemia, excess amounts of reactive oxygen species (ROS) are often involved in senescence and apoptosis of EPCs, thereby causing defective neovascularization and reduced or failed recovery. Here, we examined the cytoprotective effect of Ecklonia cava-derived antioxidant dieckol (DK) on oxidative stress-induced apoptosis in EPCs to improve EPC bioactivity for vessel repair. Although H2O2 (10 (- 3) M) increased the intracellular ROS level in EPCs, DK (10ug/ml) pretreatment suppressed the H2O2-induced ROS increase and drastically reduced the ratios of apoptotic cells. H2O2-induced ROS increased the phosphorylation of p38 MAPK and JNK; this was inhibited by DK pretreatment. H2O2 treatment increased the phosphorylation of NF-κB, which was blocked by pretreatment with SB 203580, a p38 MAPK inhibitor, or SP 600125, a JNK inhibitor. H2O2 decreased the cellular levels of Bcl-2 and c-IAPs, cellular inhibitors of apoptosis proteins, but increased caspase-3 activation. However, all these effects were inhibited by pretreatment with DK. Injection of DK-mixed EPCs (DK + EPCs) into myocardial ischemic sites in vivo induced cellular proliferation and survival of cells at the ischemic sites and, thereby, enhanced the secretion of angiogenic cytokines at the ischemic sites. These results show that DK + EPC exhibit markedly enhanced anti-apoptotic and antioxidative capabilities, unlike that shown by EPCs alone; thus, they contribute to improved repair of ischemic myocardial injury through cell survival and angiogenic cytokine production.

In this paper, we present a novel microfluidic system with pulsatile cell storing, cell-delivering and cell culturing functions on a single PDMS platform. For this purpose, we have integrated two reservoirs, a pulsatile pumping system containing two soft check valves, which were fabricated by in situ photopolymerization, six switch valves, and three cell culture chambers all developed through a simple and rapid fabrication process. The sample volume delivered per stroke was 120 nl and the transported volume was linearly related to the pumping frequency. We have investigated the effect of the pulsatile pneumatic micropumping on the cells during transport. For this purpose, we pumped two types of cell suspensions, one containing human breast adenocarcinoma cells (MCF-7) and the other mesenchymal stem cells (hMSCs) derived from bone marrow. The effect of pulsatile pumping on both cell types was examined by short and long-term culture experiments. Our results showed that the characteristics of both cells were maintained; they were not damaged by the pumping system. Evaluations were carried out by morphological inspection, viability assay and immunophenotyping analysis. The delivered MCF-7 cells and hMSCs spread and proliferated onto the gelatin coated cell culture chamber. This total micro cell culture system can be applied to cell-based high throughput screening and for co-culture of different cells with different volume.