Carine Nguemeni

University of Ottawa, Ottawa, Ontario, Canada

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Publications (5)18.31 Total impact

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    ABSTRACT: Endothelin-1 (ET-1) induced focal ischemia is increasingly being used as a preclinical model of stroke. Here, we described for the first time, the time course of neuronal death and infarct evolution during the first 7 days following ischemia. We used hematoxylin and eosin (H&E) staining to evaluate infarct progression and Fluoro-Jade C (FJC) to quantify neuronal degeneration at 24, 48, 72hours and 7 days after ET-1 injection to the forelimb motor cortex in Sprague Dawley rats. We found that infarct volume and neuronal degeneration are maximal at 24hours post-stroke. Neuronal degeneration is also significantly reduced within 7 days of stroke induction. This study is the first to provide a direct evaluation of both infarct volume evolution and neuronal death time course following ET-1 induced focal ischemia in the forelimb motor cortex. This study describes the short-term time course of neuronal death and brain injury in the ET-1 stroke model, which provides a significant reference when determining the appropriate time to commence neuroprotective or recovery promoting strategies. Copyright © 2015. Published by Elsevier B.V.
    Journal of Neuroscience Methods 01/2015; 242. DOI:10.1016/j.jneumeth.2015.01.005 · 1.96 Impact Factor
  • Dale Corbett, Carine Nguemeni, Mariana Gomez-Smith
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    ABSTRACT: Background: Stroke is a devastating disorder that strikes approximately 15 million people worldwide. While most patients survive stroke, many are left with lifelong impairments, thereby making stroke the leading cause of permanent neurological disability. Despite this, there are a few options for treatment of acute stroke. Restoration of blood flow using clot-dissolving drugs has produced impressive benefits in some patients. However, for these drugs to be effective, they must be given soon after stroke onset and relatively only a few stroke patients reach hospital within this time. Side effects of these compounds further limit their use. Summary: Enhancing the brain's endogenous capacity for reorganization and self-repair offers the most promise for victims of stroke. Indeed, many stroke patients show considerable spontaneous functional improvement. Findings in the last 15 years suggest that stroke and related injury create a cerebral milieu similar to that of early brain development, a period characterized by rapid neuronal growth and neuroplasticity. A variety of interventions (e.g., stem cells, delivery of growth factors) are currently being explored in order to enhance neuroplasticity and reorganizational processes that are important for recovery of function. An emerging concept is that combinational or 'cocktail' therapies are more effective than single interventions in improving stroke recovery. Among these, one of the most promising therapies is enriched rehabilitation, a combination of environmental enrichment and task-specific therapy (e.g., reach training). Key Messages: Neurorestorative approaches to brain reorganization and repair are providing new insights into how neural circuits respond to injury and how this knowledge can be used for optimizing stroke rehabilitation practice. © 2014 S. Karger AG, Basel.
    Cerebrovascular Diseases 11/2014; 38(4):233-239. DOI:10.1159/000368887 · 3.70 Impact Factor
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    ABSTRACT: Stroke is a worldwide main cause of mortality and morbidity. Most of the preventive and neuroprotective treatments identified in preclinical studies failed in clinical trials. Although there is a consensus that nutrition is important for health, its role is underestimated in stroke. Indeed an increase consumption of salt and fatty foods may promote hypertension and obesity, which are well known risk factors of stroke. In contrast it is more difficult to identify a risk factor arising from a deficiency in an essential nutrient in the diet. Western modern diets are deficient in omega-3 polyunsaturated fatty acids, which are essential for brain health. Such deficiency may constitute by itself a risk factor for stroke. Furthermore, an imbalance in the consumption of omega-6 and omega-3 progressively took place in the past 40 years leading to omega-6/omega-3 ratios that are far above the WHO healthy recommendations. A consequence of this imbalanced ratio has been the fostering of elevations in and increased prevalence of inflammatory cardiovascular diseases and obesity. In this context, this review outlines a promising therapeutic opportunity by integrating a nutritional-based approach focusing on omega-3 alpha-linolenic acid as nutraceutical to prevent the devastating damage caused by brain ischemia.
    01/2013; DOI:10.1016/j.phanu.2012.12.002
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    ABSTRACT: Populations of Western countries are severely deficient in omega-3 intake, both in the form of alpha-linolenic acid (ALA) and the Long Chain derivatives (LC-n-3), Eicosa-Pentaenoic-Acid and Docosa-Hexaenoic-Acid. Omega-3 insufficiency is a risk factor for cardiovascular and cerebral diseases such as coronary heart disease and stroke. Stroke is a major cause of mortality and morbidity, and induces a significant socioeconomic cost and a marked increase in patient/family burden. To date, preventive treatments and neuroprotective drugs identified in preclinical studies failed in clinical trials, in part because of an inability to tolerate drugs at neuroprotective concentrations. Therefore testing alternative protective strategies, such as functional foods/nutraceuticals, are of considerable interest. We have previously demonstrated that a single injection of ALA reduced ischemic damage by limiting glutamate-mediated neuronal death, whereas repeated injections displayed additive protective benefits as a result of increased neurogenesis, synaptogenesis and neurotrophin expression. Because intravenous injections are not a suitable long-term strategy in humans, the present study investigated the effect of ALA supplementation by an experimental diet containing rapeseed oil (RSO, a rich source of ALA) as the only source of lipids for stroke prevention. We tested several experimental diets which included 5, 10, and 20% RSO-enriched diet and feeding paradigms (fresh diet was provided once or twice a week for 4 or 6 weeks). Our results showed that ALA supplemented diets are more sensitive to lipid peroxidation than a regular chow diet. Because the diet affected feeding behavior and animal growth, we defined concrete guidelines to investigate the effect of omega-3 supplementation on neuropathology. Among the different sets of experiments, animals fed with 10% and 20% RSO-enriched diet displayed a reduced mortality rate, infarct size and increased probability of spontaneous reperfusion in the post-ischemic period. In addition, a drastic reduction of lipid peroxidation levels was observed in the ischemic brain of RSO-fed animals. Overall, our findings provide new insights into the potential of employing rapeseed oil as a functional food/nutraceutical aiding in stroke prevention and protection.
    Pharmacological Research 03/2010; 61(3):226-33. DOI:10.1016/j.phrs.2009.12.007 · 3.98 Impact Factor
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    ABSTRACT: Omega-3 polyunsaturated fatty acids are known to have therapeutic potential in several neurological and psychiatric disorders. However, the molecular mechanisms of action underlying these effects are not well elucidated. We previously showed that alpha-linolenic acid (ALA) reduced ischemic brain damage after a single treatment. To follow-up this finding, we investigated whether subchronic ALA treatment promoted neuronal plasticity. Three sequential injections with a neuroprotective dose of ALA increased neurogenesis and expression of key proteins involved in synaptic functions, namely, synaptophysin-1, VAMP-2, and SNAP-25, as well as proteins supporting glutamatergic neurotransmission, namely, V-GLUT1 and V-GLUT2. These effects were correlated with an increase in brain-derived neurotrophic factor (BDNF) protein levels, both in vitro using neural stem cells and hippocampal cultures and in vivo, after subchronic ALA treatment. Given that BDNF has antidepressant activity, this led us to test whether subchronic ALA treatment could produce antidepressant-like behavior. ALA-treated mice had significantly reduced measures of depressive-like behavior compared with vehicle-treated animals, suggesting another aspect of ALA treatment that could stimulate functional stroke recovery by potentially combining acute neuroprotection with long-term repair/compensatory plasticity. Indeed, three sequential injections of ALA enhanced protection, either as a pretreatment, wherein it reduced post-ischemic infarct volume 24 h after a 1-hour occlusion of the middle cerebral artery or as post-treatment therapy, wherein it augmented animal survival rates by threefold 10 days after ischemia.
    Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology 08/2009; 34(12):2548-59. DOI:10.1038/npp.2009.84 · 8.68 Impact Factor