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Secondary neurodegeneration resulting from stroke is mediated by delayed proinflammatory signaling and immune cell activation. Although it remains unknown which cell surface markers signify a proinflammatory phenotype, increased isolectin binding occurs on CD11b-expressing immune cells within injured brain tissue. Several reports have confirmed the efficacy of human umbilical cord blood (HUCB) cell therapy in reducing ischemic injury in rat after middle cerebral artery occlusion (MCAO), and these effects were attributed in part to dampened neuroinflammation. The present study examined the time course of lectin binding to cells of microglia/macrophage lineage within 96 hr after MCAO and whether delayed HUCB cell treatment alters the migration and/or morphological characteristics of these cells throughout the period of infarct expansion. Isolectin binding was up-regulated in response to injury, was maximal at 96 hr, and colocalized with cells that expressed the putative proinflammatory markers MMP-9 and nitric oxide. Isolectin-tagged fluorescence was also significantly increased at 72 hr and localized to greater numbers of amoeboid, CD11b-expressing cells relative to 51 hr. Treatment with 1 x 10(6) HUCB cells significantly reduced total lectin binding at 72 hr, as well as the total area occupied by lectin-tagged fluorescence at both 51 and 72 hr, relative to vehicle-treated controls. This effect was accompanied by a shift in the morphology of CD11b-positive cells from amoeboid to ramified shape. These data indicate that HUCB cell therapy suppressed the recruitment of proinflammatory, isolectin-binding cells during the period of infarct expansion, thus offering a potential mechanism for the protective effects of HUCB cell therapy., ((c) 2009 Wiley-Liss, Inc.)

Previous reports have shown that human umbilical cord blood cells (HUCBCs) administered intravenously 48 hr following middle cerebral artery occlusion reduce infarct area and behavioral deficits of rodents. This cellular therapy is potently neuroprotective and antiinflammatory. This study investigates the effect of HUCBC treatment on white matter injury and oligodendrocyte survival in a rat model of ischemia. Intravenous infusion of 10(6) HUCBCs 48 hr poststroke reduced the amount of white matter damage in vivo as seen by quantification of myelin basic protein staining in tissue sections. To determine whether HUCBC treatment was protective via direct effects on oligodendrocytes, cultured oligodendrocytes were studied in an in vitro model of oxygen glucose deprivation. Active caspase 3 immunohistochemistry and the lactate dehydrogenase assay for cytotoxicity were used to determine that HUCBCs provide protection to oligodendrocytes in vitro. Based on these results, it is likely that HUCBC administration directly protects oligodendrocytes and white matter. This effect is likely to contribute to the increased behavioral recovery observed with HUCBC therapy., (2008 Wiley-Liss, Inc.)

The developing brain is uniquely susceptible to injury after exposure to hypoxia-ischemia (H-I). Lecticans are developmentally regulated in formative white matter and exert growth-inhibitory effects in several adult injury models, yet little is known regarding their role in neonatal H-I injury. The main objectives of this study were to examine the expression profiles of brevican and versican in rat using a standard H-I model and to determine whether altered expression was associated with distinct components of white and gray matter pathology. The H-I procedure in postnatal day 7 rats produced progressive injury limited to the ipsilateral hemisphere. Cresyl violet staining revealed severe cavitary infarctions at 14 and 21 days that were absent at 4 days. Cellular damage, as measured by glial fibrillary acidic protein and fractin immunoreactivity, occurred in cortical and subcortical gray matter at all end points. O4 sulfatide immunoreactivity was reduced in the external capsule, hippocampal fimbria, and corpus striatum at 4 days relative to that contralaterally, suggesting the loss of preoligodendrocytes. Brevican expression was reduced in the cortex and hippocampus at 4 days but was markedly elevated at later end points, localizing to regions of cellular damage both in and proximal to the lesion core. However, versican was reduced in the external capsule 4 days after H-I, a reduction that was sustained up to 21 days in white matter. These data demonstrate unique expression profiles for lecticans after neonatal H-I, suggesting brevican deposition is elevated in response to progressive gray matter injury, whereas diminished versican expression may be associated with deep cerebral white matter injury.