Pre-existing interleukin 10 in cerebral arteries attenuates subsequent brain injury caused by ischemia/reperfusion.

Recurrent stroke is difficult to treat and life threatening. Transfer of anti-inflammatory gene is a potential gene therapy strategy for ischemic stroke. Using recombinant adeno-associated viral vector 1 (rAAV1)-mediated interleukin 10 (IL-10), we investigated whether transfer of beneficial gene into the rat cerebral vessels during interventional treatment for initial stroke could attenuate brain injury caused by recurrent stroke. Male Wistar rats were administered rAAV1-IL-10, rAAV1-YFP, or saline into the left cerebral artery. Three weeks after gene transfer, rats were subjected to occlusion of the left middle cerebral artery (MCAO) for 45 min followed by reperfusion for 24 h. IL-10 levels in serum were significantly elevated 3 weeks after rAAV1-IL-10 injection, and virus in the cerebral vessels was confirmed by in situ hybridization. Pre-existing IL-10 but not YFP decreased the neurological dysfunction scores, brain infarction volume, and the number of injured neuronal cells. AAV1-IL-10 transduction increased heme oxygenase (HO-1) mRNA and protein levels in the infarct boundary zone of the brain. Thus, transduction of the IL-10 gene in the cerebral artery prior to ischemia attenuates brain injury caused by ischemia/reperfusion in rats. This preventive approach for recurrent stroke can be achieved during interventional treatment for initial stroke.

Heme oxygenase-1 mediated memorial and revivable protective effect of ischemic preconditioning on brain injury.

AIMS: Ischemic preconditioning (IPC) has short-term benefits for stroke patients. However, if IPC protective effect is memorial and the role of the intracellular protective protein heme oxygenase-1 (HO-1) is not known. METHODS: Ischemic preconditioning and the corresponding sham control were achieved by blocking the blood flow of the left internal carotid artery for 20 min and 2 second, respectively, in rats. Both IPC and sham-operated animals were divided into three groups and treated with PBS, the HO-1 inducer hemin, and the HO-1 inhibitor Znpp. Three weeks after IPC, brain ischemia-reperfusion injury was achieved by left middle cerebral artery obstruction for 45 min followed by 24-h reperfusion. RESULTS: 2,3,5-triphenyltetrazolium chloride staining and neurological dysfunction scoring showed IPC significantly reduced brain infarct area and improved neurological function occurred 3 weeks after IPC. Hemin treatment promoted whereas ZnPP blocked the benefits of IPC. Immunohistochemical analysis and Western blotting showed that the expression of HO-1 was higher in the border zone than in the necrotic core zone. The memorial IPC protection is independent of adenosine receptor A1R and A2aR expressions. CONCLUSIONS: We found for the first time that the protective effect of IPC can be remembered to protect brain injury occurred after acute response disappear. The results indicate that interventional treatment can achieve protective effect for future cerebral injury not only through interventional treatment itself but also through the memorial and revivable IPC, eliminating the concern that temporary ischemia caused by interventional treatment may leave harmful effect in the brain.

Biphasic response of endothelial progenitor cell proliferation induced by high glucose and its relationship with reactive oxygen species.

In this study, the effect of high glucose (HG) on endothelial progenitor cell (EPC) proliferation and its relationship with cyclins and reactive oxygen species (ROS) were investigated. Mouse EPCs were isolated from bone marrow using a magnetic activated cell-sorting system and cultured in the presence or absence of HG (30 mmol/l). We found that in the early stage of incubation (3 days), HG promoted cell proliferation, and increased the expressions of cdk2 and cyclin E, while in the late stage of culture (7 days) it inhibited cell proliferation and decreased the expressions of cdk2, cyclin E, and proliferating cell nuclear antigen (PCNA). Moreover, on the third day after incubation, HG significantly inhibited the apoptosis of EPCs, while in the late stage it markedly activated caspase-3 and promoted apoptosis. ROS generation in cells and maleic dialdehyde level in medium were significantly increased in HG group on the seventh day, whereas the expressions of superoxide dismutase and glutathione levels decreased. Tempol, a membrane-permeable radical scavenger, significantly inhibited ROS production in EPCs and partially reversed the HG-mediated inhibition of EPCs proliferation on the seventh day. We hypothesize that in the HG environment, the biphasic response of EPC proliferation may be related to the generation of ROS, which causes modulation of cyclins and cell cycle effect.

Dynamic changes in the expression of growth factor receptors in the myocardium microvascular endothelium after murine myocardial infarction.

BACKGROUND: After myocardial infarction, specific growth factors promote cardiac angiogenisis, leading to a therapeutic effect. Although this effect is mediated by specific receptors in the endothelium of the cardiac microvasculature, few studies have investigated dynamic changes in their expression. We explored this phenomenon in a murine model. METHODS: We observed the mRNA expression of receptors by specific angiogenesis gene microarray at day 3 and day 7 after infarction. The vascular endothelial growth factor (VEGF) receptor Flk-1 was observed at the protein level at day 3 and day 7 by immunohistochemistry. The dynamic expression of fibroblast growth factor receptor-1 (FGFR-1) mRNA in the border zone and the noninfarcted zone at day 3, day 7, day 14, and day 42 was investigated by real-time PCR. Statistical significance was analyzed with SPSS 10.0 software using one-way analysis of variance (ANOVA). RESULTS: Three days after infarction, 9 receptors in the border zone and 7 receptors in the noninfarcted zone were down-regulated. Two receptors in the infarct edge and 5 receptors in the distant myocardium were up-regulated. However, at day 7, 11 receptors in the border zone were up-regulated, and only one was down-regulated. In the border zone, Flk-1 levels decreased at day 3 but increased significantly at day 7. Real-time PCR showed that FGFR-1 mRNA decreased markedly in the border zone at day 3 but increased afterward for at least 6 weeks. In the early stage (3 days) after infarction, the expression of receptors had decreased to some extent. However, at day 7, receptor expression was active and had moved from the distant noninfarcted zone to the border zone as a part of the acute repair process. CONCLUSION: Selecting the proper growth factors to target receptors with protective activity, and determining appropriate therapeutic timing may be important to the success of therapeutic angiogenesis.

Characteristics and differentiated mechanism of vascular endothelial cells-like derived from epithelial ovarian cancer cells induced by hypoxia.

A few highly aggressive and malignant tumor cells could acquire identities by turning on genes expressed by endothelial cells and recruit blood vessels to sustain tumor growth. Hypoxia was reported recently to play an essential role in these events. These 'plastic' tumor-cell phenotypes and the exact mechanism driving transendothelial differentiation by hypoxia-inducible factor (HIF)-1alpha is unclear. In this study, epithelial ovarian carcinoma cells were exposed to hypoxia and the tumor cells were transformed into endothelial cells-like (ECs-like). Typical endothelial features such as cell markers and uptaking of acetylated low density lipoprotein were identified constantly. Small interference RNA was used to block the expression of HIF-1alpha. Analysis revealed that hypoxia promotes transendothelial differentiation through stimulating HIF-1-dependent transcriptional expression of vascular endothelial growth factor (VEGF), VEGF receptor-2 (Flk-1) and P53, and through decreasing HIF-1-independent transcriptional expression of Cyclin D1. These results demonstrate that ECs-like derived from epithelial ovarian cancer cells are similar to endothelial progenitor cells rather than endothelial cells. HIF-1alpha is crucial but not unique in alternation of tumor cells towards ECs-like.