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We here suggest that pigment epithelium-derived factor (PEDF) does not have an effect on lesion size, behavioral outcome, cell proliferation, or cell death after striatal ischemia in the mouse. PEDF is a neurotrophic factor with neuroprotective, antiangiogenic, and antipermeability effects. It influences self-renewal of neural stem cells and proliferation of microglia. We investigated whether intraventricular infusion of PEDF reduces infarct size and cell death, ameliorates behavioral outcome, and influences cell proliferation in the one-hour middle cerebral artery occlusion (MCAO) mouse model of focal cerebral ischemia. C57Bl6/N mice were implanted with PEDF or artificial cerebrospinal fluid (control) osmotic pumps and subjected to 60-minute MCAO 48 hours after pump implantation. They received daily BrdU injections for 7 days after MCAO in order to investigate cell proliferation. Infarct volumes were determined 24 hours after reperfusion using magnetic resonance imaging. We removed the pumps on day 5 and performed behavioral testing between day 7 and 21. Immunohistochemical staining was performed to determine the effect of PEDF on cell proliferation and cell death. Our model produced an ischemic injury confined solely to striatal damage. We detected no reduction in infarct sizes and cell death in PEDF- vs. CSF-infused MCAO mice. Behavioral outcome and cell proliferation did not differ between the groups. However, we cannot exclude that PEDF might work under different conditions in stroke. Further studies will elucidate the effect of PEDF treatment on cell proliferation and behavioral outcome in moderate to severe ischemic injury in the brain. [ABSTRACT FROM AUTHOR]

Abstract: Evaluation of functional outcome over the course of several weeks after ischemia is a key component in improving the clinical relevance of experimental stroke studies. Using a battery of behavioral tests, we characterized functional outcome in mice over 4 weeks following 30min of proximal middle cerebral artery occlusion (MCAo). We evaluated rotarod, chimney, pole and cylinder tests to assess short term functional deficits in a transient stroke model which induces infarcts mainly in the striatum. The corner test, adhesive removal test, cylinder test, catwalk, paw preference test and novel tests of rotation were evaluated for long-term functional outcome. Rotarod detected deficits within the first week and pole test was reliable up to intermediate time points after MCAo. Corner test, adhesive removal test, catwalk and paw preference test detected deficits for up to 4 weeks, as did the novel corner rotation and bowl tests. Chimney and cylinder test did not prove useful in our model of mild stroke. In summary, we established the pole test and rotarod as useful tools to evaluate sensory motor deficits early after mild stroke, and corner test and adhesive removal test at later time-points. Alternatively, corner rotation may be a suitable test of long-term function. Test batteries may be further complemented by catwalk and paw preference test for clinically relevant deficits. There was no correlation of behavioral outcome with lesion size at 28 days, and determining whether these tests are useful for detecting a potential benefit of neuroprotective or regenerative therapies requires further testing. [Copyright &y& Elsevier]

Ambivalent effects of interleukin-6 on the pathogenesis of ischaemic stroke have been reported. However, to date, the long-term actions of interleukin-6 after stroke have not been investigated. Here, we subjected interleukin-6 knockout (IL-6−/−) and wild-type control mice to mild brain ischaemia by 30-min filamentous middle cerebral artery occlusion/reperfusion. While ischaemic tissue damage was comparable at early time points, IL-6−/− mice showed significantly increased chronic lesion volumes as well as worse long-term functional outcome. In particular, IL-6−/− mice displayed an impaired angiogenic response to brain ischaemia with reduced numbers of newly generated endothelial cells and decreased density of perfused microvessels along with lower absolute regional cerebral blood flow and reduced vessel responsivity in ischaemic striatum at 4 weeks. Similarly, the early genomic activation of angiogenesis-related gene networks was strongly reduced and the ischaemia-induced signal transducer and activator of transcription 3 activation observed in wild-type mice was almost absent in IL-6−/− mice. In addition, systemic neoangiogenesis was impaired in IL-6−/− mice. Transplantation of interleukin-6 competent bone marrow into IL-6−/− mice (IL-6chi) did not rescue interleukin-6 messenger RNA expression or the early transcriptional activation of angiogenesis after stroke. Accordingly, chronic stroke outcome in IL-6chi mice recapitulated the major effects of interleukin-6 deficiency on post-stroke regeneration with significantly enhanced lesion volumes and reduced vessel densities. Additional in vitro experiments yielded complementary evidence, which showed that after stroke resident brain cells serve as the major source of interleukin-6 in a self-amplifying network. Treatment of primary cortical neurons, mixed glial cultures or immortalized brain endothelia with interleukin 6-induced robust interleukin-6 messenger RNA transcription in each case, whereas oxygen–glucose deprivation did not. However, oxygen–glucose deprivation of organotypic brain slices resulted in strong upregulation of interleukin-6 messenger RNA along with increased transcription of key angiogenesis-associated genes. In conclusion, interleukin-6 produced locally by resident brain cells promotes post-stroke angiogenesis and thereby affords long-term histological and functional protection. [ABSTRACT FROM PUBLISHER]