Asiatic acid, a triterpenoid derivative from Centella asiatica, has shown biological effects such as antioxidant, antiinflammatory, and protection against glutamate-or β-amyloid-induced neurotoxicity. We investigated the neuroprotective effect of asiatic acid in a mouse model of permanent cerebral ischemia. Various doses of asiatic acid (30, 75, or 165 mg/kg) were administered orally at 1 hr pre-and 3, 10, and 20 hr postischemia, and infarct volume and behavioral deficits were evaluated at day 1 or 7 postischemia. IgG (blood-brain barrier integrity) and cytochrome c (apoptosis) immunostaining was carried out at 24 hr postischemia. The effect of asiatic acid on stress-induced cytochrome c release was examined in isolated mitochondrial fractions. Furthermore, its effects on cell viability and mitochondrial membrane potential were studied in HT-22 cells exposed to oxygenglucose deprivation. Asiatic acid significantly reduced the infarct volume by 60% at day 1 and by 26% at day 7 postischemia and improved neurological outcome at 24 hr postischemia. Our studies also showed that the neuroprotective properties of asiatic acid might be mediated in part through decreased blood-brain barrier permeability and reduction in mitochondrial injury. The present study suggests that asiatic acid may be useful in the treatment of cerebral ischemia.Keywords infarct volume; blood-brain barrier; oxygen-glucose deprivation; mitochondria; apoptosis Although the molecular mechanisms involved in ischemic brain injury are not fully understood, much progress has been made in identifying some pathogenic pathways, such as inflammation, excitotoxicity, mitochondrial dysfunction, and oxidative stress, that might be involved in ischemic neuronal death (Durukan and Tatlisumak, 2007 Centella asiatica is a herbaceous plant that might also have medicinal value. It is being used in Ayurvedic preparations to improve learning and memory (Zheng and Qin, 2007). Published data suggest that the plant extract has nootropic effects (Rao et al., 2005), protects the brain from age-related oxidative damage (Subathra et al., 2005), and promotes nerve growth and neuronal dendritic arborization (Mohandas et al., 2006).Asiatic acid (AA), a pentacyclic triterpene derivative from Centella asiatica, has been shown to display neuroprotective properties both in vitro and in vivo (Bonfill et al., 2006). In cellular systems, AA was reported to offer protection against β-amyloid-induced cell death in the neuroblastoma B103 cell line (Mook-Jung et al., 1999;Jew et al., 2000). It also reduced H 2 O 2 -related cell death and decreased intracellular free radical concentration (Mook-Jung et al., 1999). Furthermore, AA derivatives were effective at rescuing primary rat cortical cells from glutamate-induced toxicity through activation of the cellular oxidative defense pathway (Lee et al., 2000).Because AA exhibits numerous pharmacological activities that might be beneficial to the ischemic brain, and given that no significant toxicity was observed following subcutaneous o...
Background and Purpose-Carnosine is a naturally occurring dipeptide with multiple neuroprotective properties. In addition, it is well tolerated in high doses with minimal side effects. The purposes of this study were to determine whether carnosine is neuroprotective in permanent focal cerebral ischemia and to determine potential mechanisms of neuroprotection. Methods-We investigated the efficacy of carnosine in a mouse model of permanent focal cerebral ischemia. The effects of carnosine were investigated with respect to neuronal damage and infarct formation, endogenous antioxidant status, and matrix metalloproteinase activity. Results-Carnosine significantly decreased infarct size and neuronal damage when administered at time points both before and after the induction of ischemia. Carnosine also decreased reactive oxygen species levels in the ischemic brain, preserved normal glutathione levels, and decreased matrix metalloproteinase protein levels and activity. Conclusions-Carnosine is neuroprotective in focal cerebral ischemia and appears to influence deleterious pathological processes that are activated after the onset of ischemia.
The overall rate of bony arthrodesis was increased following the use of BMP in multilevel anterior cervical fusion. Traditional methods without BMP had a high rate of pseudarthrosis. The complications associated with the use of BMP appeared to be dose related and of low incidence when BMP is used in doses equal to or less than 1.1 mg/level.
Hypoxia is an important contributor to aggressive behavior and resistance mechanisms in glioblastoma. Upregulation of hypoxia inducible transcription factors (HIFs) is the primary adaptive cellular response to a hypoxic environment. While HIF1α has been widely studied in cancer, HIF2α offers a potentially more specific and appealing target in glioblastoma given expression in glioma stem cells and not normal neural progenitors, activation in states of chronic hypoxia and expression that correlates with glioma patient survival. A first-in-class HIF2α inhibitor, PT2385, is in clinical trials for renal cell carcinoma, and provides the first opportunity to therapeutically target this important pathway in glioma biology.
Hypoxia inducible factor (HIFs) signaling contributes to malignant cell behavior in glioblastoma (GBM). We investigated a novel HIF2α inhibitor, PT2385, both in vitro, with low-passage patient-derived cell lines, and in vivo, using orthotopic models of glioblastoma. We focused on analysis of HIF2α expression in situ, cell survival/proliferation, and survival in brain tumor-bearing mice treated with PT2385 alone and in combination with standard of care chemoradiotherapy. HIF2α expression increased with glioma grade, with over half of GBM specimens HIF2α positive. Staining clustered in perivascular and perinecrotic tumor regions. Cellular phenotype including proliferation, viability, migration/invasion, and also gene expression were not altered after PT2385 treatment. In the animal model, PT2385 single-agent treatment did improve median overall survival compared to placebo (p = 0.04, n = 21) without a bioluminescence correlate (t = 0.67, p = 0.52). No difference in animal survival was seen in combination treatment with radiation (RT)/temozolomide (TMZ)/PT2385 (p = 0.44, n = 10) or mean tumor bioluminescence (t 1.13, p = 0.32). We conclude that HIF2α is a reasonable novel therapeutic target as expressed in the majority of glioblastomas in our cohort. PT2385 as a single-agent was efficacious in vivo, however, an increase in animal survival was not seen with PT2385 in combination with RT/TMZ. Further study for targeting HIF2α as a therapeutic approach in GBM is warranted.
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