Resveratrol, a natural red wine polyphenol, reduces ischemia-reperfusion-induced spinal cord injury

Effects of Resveratrol on Vascular Function in Retinal Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) events are involved in the development of various ocular pathologies, e.g., retinal artery or vein occlusion. We tested the hypothesis that resveratrol is protective against I/R injury in the murine retina. Intraocular pressure (IOP) was elevated in anaesthetized mice to 110 mm Hg for 45 min via a micropipette placed in the anterior chamber to induce ocular ischemia. In the fellow eye, which served as control, IOP was kept at a physiological level. One group received resveratrol (30 mg/kg/day p.o. once daily) starting one day before the I/R event, whereas the other group of mice received vehicle solution only. On day eight after the I/R event, mice were sacrificed and retinal wholemounts were prepared and immuno-stained using a Brn3a antibody to quantify retinal ganglion cells. Reactivity of retinal arterioles was measured in retinal vascular preparations using video microscopy. Reactive oxygen species (ROS) and nitrogen species (RNS) were quantified in ocular cryosections by dihydroethidium and anti-3-nitrotyrosine staining, respectively. Moreover, hypoxic, redox and nitric oxide synthase gene expression was quantified in retinal explants by PCR. I/R significantly diminished retinal ganglion cell number in vehicle-treated mice. Conversely, only a negligible reduction in retinal ganglion cell number was observed in resveratrol-treated mice following I/R. Endothelial function and autoregulation were markedly reduced, which was accompanied by increased ROS and RNS in retinal blood vessels of vehicle-exposed mice following I/R, whereas resveratrol preserved vascular endothelial function and autoregulation and blunted ROS and RNS formation. Moreover, resveratrol reduced I/R-induced mRNA expression for the prooxidant enzyme, nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2). Our data provide evidence that resveratrol protects from I/R-induced retinal ganglion cell loss and endothelial dysfunction in the murine retina by reducing nitro-oxidative stress possibly via suppression of NOX2 upregulation.

Effects of resveratrol on renal ischemia-reperfusion injury: A systematic review and meta-analysis

Renal ischemia-reperfusion (I/R) injury may lead to acute kidney injury, which is characterized by high morbidity and mortality rates. Resveratrol (RSV) can be extracted from Chinese herbs, and multiple animal experiments have demonstrated its potential for renal protection. This systematic review evaluates the protective effect of RSV against renal I/R injury in animal models. The PubMed, Embase, Web of Science, and Science Direct databases were searched for animal experiments related to RSV in renal I/R injury from their establishment to June 2022. In total, 19 studies were included with 249 animals (129 treated with RSV and 120 as controls). The pooled analysis revealed that RSV administration significantly decreased serum creatinine (SCr) levels (16 studies, n = 243, WMD = -58.13, 95% CI = -79.26 to -37.00, p < 0.00001) and blood urea nitrogen (BUN) levels (12 studies, n = 163, WMD = -34.37, 95% CI = -46.70 to -22.03, p < 0.00001) in the renal I/R injury model. The level of malondialdehyde (MDA), an oxidative stress index, was alleviated [7 studies, n = 106, standardized mean difference (SMD) = -6.05, 95% CI = -8.90 to -3.21, p < 0.0001] and antioxidant enzymes such as glutathione (GSH) (7 studies, n = 115, SMD = 9.25, 95% CI = 5.51-13.00, p < 0.00001) and catalase (CAT) (4 studies, n = 59, SMD = 8.69, 95% CI = 4.35-13.03, p < 0.0001) were increased after treatment of RSV. The subgroup analysis suggested that 5-10 mg/kg of RSV optimally protects against renal I/R injury as both the BUN and SCr levels were significantly decreased at this dosage. The protective effects of RSV against renal I/R injury might be attributed to multiple mechanisms, such as inhibiting oxidative stress, apoptosis, inflammation, fibrillation, and promoting autophagy. For a deeper understanding of the protective effects of RSV, experimental studies on animal models and large randomized controlled trials in humans are needed.

Stem cell treatment trials of spinal cord injuries in animals

BACKGROUND

Spinal cord injury (SCI) is a serious neurological spinal cord damage that resulted in the loss of temporary or permanent function. However, there are even now no effective therapies for it. So, a new medical promising therapeutic hotspot over the previous decades appeared which was (Stem cell (SC) cure of SCI). Otherwise, animal models are considered in preclinical research as a model for humans to trial a potential new treatment.

METHODOLOGY

Following articles were saved from different databases (PubMed, Google scholar, Egyptian knowledge bank, Elsevier, Medline, Embase, ProQuest, BMC) on the last two decades, and data were obtained then analyzed.

RESULTS

This review discusses the type and grading of SCI. As well as different types of stem cells therapy for SCI, including mesenchymal stem cells (MSCs), neural stem cells (NSCs), hematopoietic stem cells (HSCs), induced pluripotent stem cells (iPSCs), and embryonic stem cells (ESCs). The review focuses on the transplantation pathways, clinical evaluation, and clinical signs of different types of SC on different animal models which are summarized in tables to give an easy to reach.

CONCLUSION

Pharmacological and physiotherapy have limited regenerative power in comparison with stem cells medication in the treatment of SCI. Among several sources of cell therapies, mesenchymal stromal/stem cell (MSC) one is being progressively developed as a trusted important energetic way to repair and regenerate. Finally, a wide-ranged animal models have been condensed that helped in human clinical trial therapies.

Histological Findings After Aortic Cross-Clamping in Preclinical Animal Models

Spinal cord ischemic injury and paralysis are devastating complications after open surgical repair of thoracoabdominal aortic aneurysms. Preclinical models have been developed to simulate the clinical paradigm to better understand the neuropathophysiology and develop therapeutic treatment. Neuropathological findings in the preclinical models have not been comprehensively examined before. This systematic review studies the past 40 years of the histological findings after open surgical repair in preclinical models. Our main finding is that damage is predominantly in the grey matter of the spinal cord, although white matter damage in the spinal cord is also reported. Future research needs to examine the neuropathological findings in preclinical models after endovascular repair, a newer type of surgical repair used to treat aortic aneurysms.

Nutritional interventions for spinal cord injury: preclinical efficacy and molecular mechanisms

Spinal cord injury (SCI) is a debilitating condition that leads to motor, sensory, and autonomic impairments. Its intrinsic pathophysiological complexity has hindered the establishment of effective treatments for decades. Nutritional interventions (NIs) for SCI have been proposed as a route to circumvent some of the problems associated with this condition. Results obtained in animal models point to a more holistic effect, rather than to specific modulation, of several relevant SCI pathophysiological processes. Indeed, published data have shown NI improves energetic imbalance, oxidative damage, and inflammation, which are promoters of improved proteostasis and neurotrophic signaling, leading ultimately to neuroprotection and neuroplasticity. This review focuses on the most well-documented Nis. The mechanistic implications and their translational potential for SCI are discussed.

Therapeutic Effects of Resveratrol on Ischemia-Reperfusion Injury in the Nervous System

Resveratrol is a phenol compound produced by some plants in response to pathogens, infection, or physical injury. It is well-known that resveratrol has antioxidant and protective roles in damages potentially caused by cancer or other serious disorders. Thus, it is considered as a candidate agent for the prevention and treatment of human diseases. Evidence has confirmed other bioactive impacts of resveratrol, including cardioprotective, anti-tumorigenic, anti-inflammatory, phytoestrogenic, and neuroprotective effects. Ischemia-reperfusion (IR) can result in various disorders, comprising myocardial infarction, stroke, and peripheral vascular disease, which may continue to induce debilitating conditions and even mortality. In virtue of chronic ischemia or hypoxia, cells switch to anaerobic metabolism, giving rise to some dysfunctions in mitochondria. As the result of lactate accumulation, adenosine triphosphate levels and pH decline in cells. This condition leads cells to apoptosis, necrosis, and autophagy. However, restoring oxygen level upon reperfusion after ischemia by producing reactive oxygen species is an outcome of mitochondrial dysfunction. Considering the neuroprotective effect of resveratrol and neuronal injury that comes from IR, we focused on the mechanism(s) involved in IR injury in the nervous system and also on the functions of resveratrol in the protection, inhibition, and treatment of this injury.

Effects of trans- versus cis-resveratrol on adrenergic contractions of the rat tail artery and role of endothelium

The health benefits of the natural polyphenol trans‐resveratrol may play an important role in preventing a variety of diseases. Resveratrol has been shown to reduce blood pressure and improve metabolic diseases such as type 2 diabetes mellitus and obesity. Our previous studies examined the role of K⁺ channels in the vasorelaxation responses to trans‐resveratrol in the rat tail artery. During these studies, we uncovered a novel transient contraction prior to the sustained relaxation effect of trans‐resveratrol. Thus, the purpose of this study was to determine the role of the endothelium in these vascular contraction and relaxation responses to trans‐resveratrol. We additionally sought to determine if the cis‐isomer of resveratrol exerts any of the same vascular effects as the trans‐isomer. The vascular responses to trans‐resveratrol were examined in rat tail arteries with intact or denuded endothelium over a 2‐hr period. Additionally, the vascular responses to trans‐ and cis‐resveratrol were compared in rat tail arteries with intact endothelium. Both the transient contractile response and the persistent relaxation response to trans‐resveratrol were similar in the arterial rings with intact or denuded endothelium. There was a significant correlation between the initial contraction‐enhancing action of trans‐resveratrol and the magnitude of the sustained relaxation for vessels with both intact and denuded endothelium. Moreover, we demonstrated that cis‐resveratrol produced a significantly greater relaxation response as compared to trans‐resveratrol without the initial contractile response. These data demonstrate the role of the vascular smooth muscle in the vascular responses to resveratrol and the potential clinical benefits of the cis‐isomer of resveratrol as compared to the trans‐isomer.

The Importance of Natural Antioxidants in the Treatment of Spinal Cord Injury in Animal Models: An Overview

Patients with spinal cord injury (SCI) face devastating health, social, and financial consequences, as well as their families and caregivers. Reducing the levels of reactive oxygen species (ROS) and oxidative stress are essential strategies for SCI treatment. Some compounds from traditional medicine could be useful to decrease ROS generated after SCI. This review is aimed at highlighting the importance of some natural compounds with antioxidant capacity used in traditional medicine to treat traumatic SCI. An electronic search of published articles describing animal models of SCI treated with natural compounds from traditional medicine was conducted using the following terms: Spinal Cord Injuries (MeSH terms) AND Models, Animal (MeSH terms) AND [Reactive Oxygen Species (MeSH terms) AND/OR Oxidative Stress (MeSH term)] AND Medicine, Traditional (MeSH terms). Articles reported from 2010 to 2018 were included. The results were further screened by title and abstract for studies performed in rats, mice, and nonhuman primates. The effects of these natural compounds are discussed, including their antioxidant, anti-inflammatory, and antiapoptotic properties. Moreover, the antioxidant properties of natural compounds were emphasized since oxidative stress has a fundamental role in the generation and progression of several pathologies of the nervous system. The use of these compounds diminishes toxic effects due to their high antioxidant capacity. These compounds have been tested in animal models with promising results; however, no clinical studies have been conducted in humans. Further research of these natural compounds is crucial to a better understanding of their effects in patients with SCI.

Effects of resveratrol and oxyresveratrol on hippocampal cell death induced by kainic acid

In the present study, we have examined the possible neuroprotective effects of resveratrol and oxyresveratrol against kainic-acid (KA)-induced hippocampal neuronal cell death. Either resveratrol or oxyresvertrol was orally administered 30 min prior to intracerebroventricular (i.c.v.) administration with KA (0.05 μg). Oral pretreatment with oxyresveratrol (50 mg/kg) significantly protected KA-induced hippocampal CA3 neuronal cell death. However, the same dose (50 mg/kg) or a higher dose (100 mg/kg) pretreatment with resveratrol did not affect KA-induced hippocampal neuronal cell death. Furthermore, the i.c.v. pretreatment with 30 μg of oxyresveratrol or resveratrol did not show the protective effect against KA-induced hippocampal neuronal cell death. In the immunohistochemical analysis, FoxO3a and pFoxO3a expressions in the hippocampal CA3 region were significantly increased 30 min after KA administration. Oral pretreatment with oxyresveratrol (50 mg/kg) significantly reduced KA-induced Forkhead homeobox type O3a (FoxO3a) and pFoxO3a expression in CA3 region of the hippocampus, suggesting that oxyresveratrol may exert a neuroprotective effect against KA-induced hippocampal neuronal cell death by reducing the levels of FoxO3a and pFoxO3a protein expression in the hippocampal CA3 region. Furthermore, it is suggested that the neuroprotective effect of orally administered oxyresveratrol against KA-induced neurotoxicity might be possibly mediated by some metabolites rather than direct action of oxyresveratrol on the central nervous system.

Resveratrol Regulates BDNF, trkB, PSA-NCAM, and Arc Expression in the Rat Cerebral Cortex after Bilateral Common Carotid Artery Occlusion and Reperfusion

The polyphenol resveratrol (RVT) may drive protective mechanisms of cerebral homeostasis during the hypoperfusion/reperfusion triggered by the transient bilateral common carotid artery occlusion followed by reperfusion (BCCAO/R). This immunochemical study investigates if a single dose of RVT modulates the plasticity-related markers brain-derived neurotrophic factor (BDNF), the tyrosine kinase trkB receptor, Polysialylated-Neural Cell Adhesion Molecule (PSA-NCAM), and Activity-regulated cytoskeleton-associated (Arc) protein in the brain cortex after BCCAO/R. Frontal and temporal-occipital cortical regions were examined in male Wistar rats randomly subdivided in two groups, sham-operated and submitted to BCCAO/R. Six hours prior to surgery, half the rats were gavage fed a dose of RVT (180 mg·kg⁻¹ in 300 µL of sunflower oil as the vehicle), while the second half was given the vehicle alone. In the frontal cortex of BCCAO/R vehicle-treated rats, BDNF and PSA-NCAM decreased, while trkB increased. RVT pre-treatment elicited an increment of all examined markers in both sham- and BCCAO/R rats. No variations occurred in the temporal-occipital cortex. The results highlight a role for RVT in modulating neuronal plasticity through the BDNF-trkB system and upregulation of PSA-NCAM and Arc, which may provide both trophic and structural local support in the dynamic changes occurring during the BCCAO/R, and further suggest that dietary supplements such as RVT are effective in preserving the tissue potential to engage plasticity-related events and control the functional response to the hypoperfusion/reperfusion challenge.

Preventive Effects of Resveratrol on Endocannabinoid System and Synaptic Protein Modifications in Rat Cerebral Cortex Challenged by Bilateral Common Carotid Artery Occlusion and Reperfusion

This study aims to evaluate the putative roles of a single acute dose of resveratrol (RVT) in preventing cerebral oxidative stress induced by bilateral common carotid artery occlusion, followed by reperfusion (BCCAO/R) and to investigate RVT’s ability to preserve the neuronal structural integrity. Frontal and temporal-occipital cortices were examined in two groups of adult Wistar rats, sham-operated and submitted to BCCAO/R. In both groups, 6 h before surgery, half the rats were gavage-fed with a single dose of RVT (40 mg/per rat in 300 µL of sunflower oil as the vehicle), while the second half received the vehicle alone. In the frontal cortex, RVT pre-treatment prevented the BCCAO/R-induced increase of lipoperoxides, augmented concentrations of palmitoylethanolamide and docosahexaenoic acid, increased relative levels of the cannabinoid receptors type 1 (CB1) and 2 (CB2), and peroxisome-proliferator-activated-receptor (PPAR)-α proteins. Increased expression of CB1/CB2 receptors mirrored that of synaptophysin and post-synaptic density-95 protein. No BCCAO/R-induced changes occurred in the temporal-occipital cortex. Collectively, our results demonstrate that, in the frontal cortex, RVT pre-treatment prevents the BCCAO/R-induced oxidative stress and modulates the endocannabinoid and PPAR-α systems. The increased expression of synaptic structural proteins further suggests the possible efficacy of RVT as a dietary supplement to preserve the nervous tissue metabolism and control the physiological response to the hypoperfusion/reperfusion challenge.

Resveratrol Attenuates Neurodegeneration and Improves Neurological Outcomes after Intracerebral Hemorrhage in Mice

Intracerebral hemorrhage (ICH) is a devastating type of stroke with a substantial public health impact. Currently, there is no effective treatment for ICH. The purpose of the study was to evaluate whether the post-injury administration of Resveratrol confers neuroprotection in a pre-clinical model of ICH. To this end, ICH was induced in adult male CD1 mice by collagenase injection method. Resveratrol (10 mg/kg) or vehicle was administered at 30 min post-induction of ICH and the neurobehavioral outcome, neurodegeneration, cerebral edema, hematoma resolution and neuroinflammation were assessed. The Resveratrol treatment significantly attenuated acute neurological deficits, neurodegeneration and cerebral edema after ICH in comparison to vehicle treated controls. Further, Resveratrol treated mice exhibited improved hematoma resolution with a concomitant reduction in the expression of proinflammatory cytokine, IL-1β after ICH. Altogether, the data suggest the efficacy of post-injury administration of Resveratrol in improving acute neurological function after ICH.

Resveratrol can both enhance and relax adrenergic contractions of the rat tail artery

Our aims were to determine 1) if resveratrol's vasorelaxant action is greater in the distal (resistance) versus proximal (conductance) portion of the rat tail artery, and 2) if it can be blocked by agents known to block different potassium (K) channels in arterial smooth muscle. We found that its half-maximally effective concentration values were essentially identical (25 ± 3 versus 27 ± 3 μM) for relaxing adrenergically-precontracted rings prepared from distal versus proximal tissues. This does not confirm a previous report of greater relaxation in resistance versus conductance arteries. We also found that its relaxation could not be blocked by any of seven different K channel blockers. However, we uncovered a novel unanticipated action not yet reported. In half our arterial ring preparations, resveratrol transiently enhanced adrenergically-induced precontractions beginning well before its sustained relaxant effect became apparent. This action provides the first reasonable explanation for previously unexplained increases in arterial pressures observed during acute intravenous administration of resveratrol to animal models of traumatic ischemic tissue injury, in which hypotension is often present and in need of correction. Also unanticipated, this same transient enhancement of adrenergic contraction was notably inhibited by some of the same K channel blockers (particularly tetraethylammonium and glibenclamide) that failed to influence its relaxant effect. Although we do not rule out smooth muscle as a possible site for such a paradoxical finding, we suspect resveratrol could also be acting on K-selective mechano-sensitive ion channels located in the endothelium where they may participate in release of contracting factors.

Multiple organ dysfunction and systemic inflammation after spinal cord injury: a complex relationship

Spinal cord injury (SCI) is a devastating event that results in significant physical disabilities for affected individuals. Apart from local injury within the spinal cord, SCI patients develop a variety of complications characterized by multiple organ dysfunction or failure. These disorders, such as neurogenic pain, depression, lung injury, cardiovascular disease, liver damage, kidney dysfunction, urinary tract infection, and increased susceptibility to pathogen infection, are common in injured patients, hinder functional recovery, and can even be life threatening. Multiple lines of evidence point to pathological connections emanating from the injured spinal cord, post-injury systemic inflammation, and immune suppression as important multifactorial mechanisms underlying post-SCI complications. SCI triggers systemic inflammatory responses marked by increased circulation of immune cells and pro-inflammatory mediators, which result in the infiltration of inflammatory cells into secondary organs and persistence of an inflammatory microenvironment that contributes to organ dysfunction. SCI also induces immune deficiency through immune organ dysfunction, resulting in impaired responsiveness to pathogen infection. In this review, we summarize current evidence demonstrating the relevance of inflammatory conditions and immune suppression in several complications frequently seen following SCI. In addition, we highlight the potential pathways by which inflammatory and immune cues contribute to multiple organ failure and dysfunction and discuss current anti-inflammatory approaches used to alleviate post-SCI complications. A comprehensive review of this literature may provide new insights into therapeutic strategies against complications after SCI by targeting systemic inflammation.

Resveratrol preconditioning induces cerebral ischemic tolerance but has minimal effect on cerebral microRNA profiles

The health benefits of the plant-derived polyphenol resveratrol were established in multiple disease systems. Notably, pre-treatment with resveratrol was shown to be neuroprotective in several models of cerebral ischemia. Mechanisms of resveratrol-mediated neuroprotection have been explored in the context of canonical resveratrol targets, but epigenetic and non-coding RNA processes have not yet been evaluated. Resveratrol was shown to alter microRNAs in cancer and cardiac ischemia. Previous studies also showed that ischemic preconditioning that induces ischemic tolerance significantly alters cerebral microRNA levels, particularly those that target neuroprotective pathways. Therefore, we tested if resveratrol-mediated ischemic tolerance also alters microRNA expression with a goal to identify microRNAs that are amenable to manipulation to induce neuroprotection after cerebral ischemia. Hence, we tested the microRNA profiles in mouse brain following intraperitoneal administration of resveratrol that induced significant tolerance against transient focal ischemia. We analyzed microRNA profiles using microarrays from both Affymetrix and LC Sciences that contain probes for all known mouse microRNAs. The results show that there is no consistent change in any of the microRNAs tested between resveratrol and vehicle groups indicating that microRNAs play a minimal role in resveratrol-mediated cerebral ischemic tolerance.

Therapeutic Effects of Traditional Chinese Medicine on Spinal Cord Injury: A Promising Supplementary Treatment in Future

Objective. Spinal cord injury (SCI) is a devastating neurological disorder caused by trauma. Pathophysiological events occurring after SCI include acute, subacute, and chronic phases, while complex mechanisms are comprised. As an abundant source of natural drugs, Traditional Chinese Medicine (TCM) attracts much attention in SCI treatment recently. Hence, this review provides an overview of pathophysiology of SCI and TCM application in its therapy. Methods. Information was collected from articles published in peer-reviewed journals via electronic search (PubMed, SciFinder, Google Scholar, Web of Science, and CNKI), as well as from master's dissertations, doctoral dissertations, and Chinese Pharmacopoeia. Results. Both active ingredients and herbs could exert prevention and treatment against SCI, which is linked to antioxidant, anti-inflammatory, neuroprotective, or antiapoptosis effects. The detailed information of six active natural ingredients (i.e., curcumin, resveratrol, epigallocatechin gallate, ligustrazine, quercitrin, and puerarin) and five commonly used herbs (i.e., Danshen, Ginkgo, Ginseng, Notoginseng, and Astragali Radix) was elucidated and summarized. Conclusions. As an important supplementary treatment, TCM may provide benefits in repair of injured spinal cord. With a general consensus that future clinical approaches will be diversified and a combination of multiple strategies, TCM is likely to attract greater attention in SCI treatment.

Resveratrol neuroprotection in stroke and traumatic CNS injury

Resveratrol, a stilbene formed in many plants in response to various stressors, elicits multiple beneficial effects in vertebrates. Particularly, resveratrol was shown to have therapeutic properties in cancer, atherosclerosis and neurodegeneration. Resveratrol-induced benefits are modulated by multiple synergistic pathways that control oxidative stress, inflammation and cell death. Despite the lack of a definitive mechanism, both in vivo and in vitro studies suggest that resveratrol can induce a neuroprotective state when administered acutely or prior to experimental injury to the CNS. In this review, we discuss the neuroprotective potential of resveratrol in stroke, traumatic brain injury and spinal cord injury, with a focus on the molecular pathways responsible for this protection.

Resveratrol inhibits matrix metalloproteinases to attenuate neuronal damage in cerebral ischemia: a molecular docking study exploring possible neuroprotection

The main pathophysiology of cerebral ischemia is the structural alteration in the neurovascular unit, coinciding with neurovascular matrix degradation. Resveratrol has been reported to be one of the most potent chemopreventive agents that can inhibit cellular processes associated with ischemic stroke. Matrix metalloproteinases (MMPs) has been considered as a potential drug target for the treatment of cerebral ischemia. To explore this, we tried to investigate the interaction of resveratrol with MMPs through molecular docking studies. At 30 minutes before and 2 hours after cerebral ischemia/reperfusion induced by occlusion of the middle cerebral artery, 40 mg/kg resveratrol was intraperitoneally administered. After resveratrol administration, neurological function and brain edema were significantly alleviated, cerebral infarct volume was significantly reduced, and nitrite and malondialdehyde levels in the cortical and striatal regions were significantly decreased. The molecular docking study of resveratrol and MMPs revealed that resveratrol occupied the active site of MMP-2 and MMP-9. The binding energy of the complexes was -37.848672 kJ/mol and -36.6345 kJ/mol for MMP-2 and MMP-9, respectively. In case of MMP-2, Leu 164, Ala 165 and Thr 227 were engaged in H-Bonding with resveratrol and in case of MMP-9, H-bonding was found with Glu 402, Ala 417 and Arg 424 residues. These findings collectively reveal that resveratrol exhibits neuroprotective effects on cerebral ischemia through inhibiting MMP-2 and MMP-9 activity.

Organ-Protective Effects of Red Wine Extract, Resveratrol, in Oxidative Stress-Mediated Reperfusion Injury

Resveratrol, a polyphenol extracted from red wine, possesses potential antioxidative and anti-inflammatory effects, including the reduction of free radicals and proinflammatory mediators overproduction, the alteration of the expression of adhesion molecules, and the inhibition of neutrophil function. A growing body of evidence indicates that resveratrol plays an important role in reducing organ damage following ischemia- and hemorrhage-induced reperfusion injury. Such protective phenomenon is reported to be implicated in decreasing the formation and reaction of reactive oxygen species and pro-nflammatory cytokines, as well as the mediation of a variety of intracellular signaling pathways, including the nitric oxide synthase, nicotinamide adenine dinucleotide phosphate oxidase, deacetylase sirtuin 1, mitogen-activated protein kinase, peroxisome proliferator-activated receptor-gamma coactivator 1 alpha, hemeoxygenase-1, and estrogen receptor-related pathways. Reperfusion injury is a complex pathophysiological process that involves multiple factors and pathways. The resveratrol is an effective reactive oxygen species scavenger that exhibits an antioxidative property. In this review, the organ-protective effects of resveratrol in oxidative stress-related reperfusion injury will be discussed.

Neuroprotective effects of testosterone on ischemia/reperfusion injury of the rabbit spinal cord

AIM

Previous studies demonstrated the neuroprotective effects of testosterone, but no previous study has examined the neuroprotective effects of testosterone on spinal cord ischemia/reperfusion injury. The purpose of this study was to evaluate whether testosterone could protect the spinal cord from ischemia/reperfusion injury.

METHODS

Rabbits were randomised into four groups of eight animals as follows: group 1 (control), group 2 (ischemia), group 3 (methylprednisolone) and group 4 (testosterone). In the control group only a laparotomy was performed. In all other groups, the spinal cord ischemia model was created by the occlusion of the aorta just caudal to the renal artery. Levels of malondialdehyde and catalase were analysed, as were the activities of caspase-3, myeloperoxidase, and xanthine oxidase. Histopathological and ultrastructural evaluations were performed. Neurological evaluation was performed with the Tarlov scoring system.

RESULTS

After ischemia-reperfusion injury, increases were found in caspase-3 activity, myeloperoxidase activity, malondialdehyde levels, and xanthine oxidase activity. In contrast, decreases in catalase levels were observed. After the administration of testosterone, decreases were observed in caspase-3 activity, myeloperoxidase activity, malondialdehyde levels, and xanthine oxidase activity, whereas catalase levels increased. Furthermore, testosterone treatment showed improved results concerning histopathological scores, ultrastructural score and Tarlov scores.

CONCLUSIONS

Our results revealed for the first time that testosterone exhibits meaningful neuroprotective activity following ischemia-reperfusion injury of the spinal cord.

Natural polyphenols and spinal cord injury

Polyphenols have been shown to have some of the neuroprotective effects against neurodegenerative diseases. These effects are attributed to a variety of biological activities, including free radical scavenging/antioxidant and anti-inflammatory and anti-apoptotic activities. In this regard, many efforts have been made to study the effects of various well-known dietary polyphenols on spinal cord injury (SCI) and to explore the mechanisms behind the neuroprotective effects. The aim of this paper is to present the mechanisms of neuroprotection of natural polyphenols used in animal models of SCI.

Neuroprotective properties of the marine carotenoid astaxanthin and omega-3 fatty acids, and perspectives for the natural combination of both in krill oil

The consumption of marine fishes and general seafood has long been recommended by several medical authorities as a long-term nutritional intervention to preserve mental health, hinder neurodegenerative processes, and sustain cognitive capacities in humans. Most of the neurological benefits provided by frequent seafood consumption comes from adequate uptake of omega-3 and omega-6 polyunsaturated fatty acids, n-3/n-6 PUFAs, and antioxidants. Optimal n-3/n-6 PUFAs ratios allow efficient inflammatory responses that prevent the initiation and progression of many neurological disorders. Moreover, interesting in vivo and clinical studies with the marine antioxidant carotenoid astaxanthin (present in salmon, shrimp, and lobster) have shown promising results against free radical-promoted neurodegenerative processes and cognition loss. This review presents the state-of-the-art applications of n-3/n-6 PUFAs and astaxanthin as nutraceuticals against neurodegenerative diseases associated with exacerbated oxidative stress in CNS. The fundamental “neurohormesis” principle is discussed throughout this paper. Finally, new perspectives for the application of a natural combination of the aforementioned anti-inflammatory and antioxidant agents (found in krill oil) are also presented herewith.

Trehalose protects against spinal cord ischemia in rabbits

OBJECTIVE

This study tested to see if trehalose, a cytoprotective disaccharide, protects against spinal cord ischemia in a rabbit model.

METHODS

The infrarenal aorta was mobilized in four groups of 10 rabbits. In groups I, II, and III, it was clamped proximally and distally for 20 minutes. In group I, the clamped aorta was infused at 2.5 L/min for 2 hours with lactated Ringer's (LR) solution. In group II, the clamped aorta was infused with 5% trehalose in LR. LR was administered intravenously (2.0 mL/min) in groups I and II starting 30 minutes before clamping. In group III, 5% trehalose in LR was infused intravenously only. Group IV was a sham-operated control group without aortic clamping. At 8, 24, and 48 hours after reperfusion, hind limb function was scored using the Tarlov score (paralysis = 0, perceptible joint movement = 1, good joint movement but unable to stand = 2, able to walk = 3, normal = 4). Histologic analysis and electron microscopy were performed on anterior horn cells.

RESULTS

The Tarlov scores in groups I, II, and III were, respectively, 1.1 ± 1.4, 3.5 ± 0.5, and 2.9 ± 0.9 at 8 hours; 0.8 ± 1.2, 3.9 ± 0.3, and 2.9 ± 0.9 at 24 hours; and 0.6 ± 0.7, 3.9 ± 0.3, and 2.7 ± 0.9 at 48 hours after reperfusion. Group IV scores were normal (4 ± 0) at all assessments. These scores were higher in groups II and III than in group I (P < .01) at all assessments. Scores at 24 and 48 hours were higher in group II than in group III (P < .05). In group III, delayed paraparesis developed in one rabbit at 24 hours and in two more at 48 hours. Histopathologic analysis showed the number of normal neurons was higher in groups II (P < .0001), III (P = .006), and IV (P < .0001) vs group I. Electron microscopy confirmed preserved neuronal cell ultrastructure in rabbits with normal limb function.

CONCLUSIONS

Transaortic trehalose infusion was protective against paraplegia, whereas intravenous trehalose reduced spinal cord ischemia. This study was preliminary and further studies are needed.

Resveratrol protects spinal cord dorsal column from hypoxic injury by activating Nrf-2

Damage from oxidative stress plays a critical role in spinal cord injury. Nuclear factor erythroid 2-related factor (Nrf-2) signaling pathway can be activated by cellular oxidative stress. Resveratrol, a plant-derived polyphenolic compound found in red wine, has antioxidant properties. In the present study, we have examined the neuroprotective effect of resveratrol and the role of Nrf-2 in spinal cord hypoxic injury. The spinal cord was removed from adult male Wistar rats from T2-T10 and the dorsal column was used to induce hypoxic injury in vitro with and without treatment with resveratrol (50μM). Significant changes were found in the compound action potential (CAP) of spinal cord dorsal column, and hematoxyline and eosin (H&E) staining showed that resveratrol significantly improved neuronal injury. The biochemical assays showed significant changes in lipid peroxidase (LPO), reduced glutathione (GSH), superoxide dismutase (SOD), protein carbonyl (PC), mitochondrial ATP content, and mitochondrial Ca(++). Furthermore, using immunohistochemistry and Western blot, we found that after resveratrol treatment during hypoxic injury there was a significant activation of NrF-2 and down regulation of the glial fibrillary acidic protein (GFAP) content. The results show that resveratrol treatment has neuroprotective effects on CAP, Ca(++) loading, and biochemical parameters after hypoxic injury. The neuroprotective effect is likely to be exerted by increased activation of transcription factor Nrf-2 by resveratrol along with its direct antioxidant effect to ameliorate the oxidative damage and preserve mitochondrial function.

Mechanisms of injury and emergency care of acute spinal cord injury in dogs and cats

OBJECTIVES

To review the literature in regards to the pathophysiology of acute spinal cord injury, and to describe current concepts in regards to patient assessment, diagnostic, and therapeutic measures with a special emphasis on emergency and critical care considerations.

ETIOLOGY

Acute spinal cord injury occurs in 2 phases. The primary injury occurs at the time of initial injury and may include intervertebral disk herniation, vertebral fracture or luxation, penetrating injury, and vascular anomalies such as fibrocartilaginous embolic myelopathy. Secondary injury occurs following primary injury and is multifactorial encompassing numerous biochemical and vascular events that result in progression of injury.

DIAGNOSIS

The diagnosis is based on history and physical examination findings. A neurologic examination should be performed following initial patient assessment and stabilization. Further diagnostics to characterize acute spinal injury include radiographs and advanced imaging modalities such as myelography, computed tomography, or magnetic resonance imaging.

THERAPY

Initial treatment should focus on addressing the patient's cardiovascular and respiratory system. Supportive measures to support systemic perfusion are vital to minimizing secondary injury. Specific therapy toward minimizing secondary injury in veterinary medicine remains controversial, especially in regards to the utilization of methylprednisolone. Other therapies are either in need of additional research or have failed to document clinical difference.

PROGNOSIS

The prognosis for acute spinal injury is varied and is dependent upon the presence of concurrent trauma, location, and type of primary injury sustained, and extent of neurologic impairment at the time of initial presentation. The etiology of the underlying trauma is of great importance in determining prognosis and outcome. Loss of deep pain is generally accepted as a poor prognostic indicator; however, even these patients can recover depending on their response to treatment.

Postconcussion syndrome: a review of pathophysiology and potential nonpharmacological approaches to treatment

The incidence of all-cause concussions in the United States is estimated to range from 1.6 to 3.8 million annually, with the reported number of sport- or recreation-related concussions increasing dramatically, especially in youth sports.(1,2) Additionally, the use of roadside bombs in Iraq and Afghanistan has propelled the incidence of concussion and other traumatic brain injuries to the highest levels ever encountered by the US military. As a result, there has also been a marked increase in postconcussion syndrome (PCS) and the associated cognitive, emotional, and memory disabilities associated with the condition. Unfortunately, however, there have been no significant advancements in the understanding or treatment of PCS for decades. The current management of PCS mainly consists of rest, reduction of sensory inputs, and treating symptoms as needed. Recently, researchers investigating the underlying mechanisms of PCS have proposed that activation of the immune inflammatory response may be an underlying pathophysiology that occurs in those who experience prolonged symptoms after a concussion. This article reviews the literature and summarizes the immune inflammatory response known as immunoexcitotoxicity. This article also discusses the use of nonpharmacological agents for the management of PCS that directly address this underlying mechanism.

Use of engineered bone marrow stem cells to deliver brain derived neurotrophic factor under the control of a tetracycline sensitive response element in experimental allergic encephalomyelitis

Brain derived neurotrophic factor (BDNF) has neuroprotective properties but its use has been limited by poor penetration of the blood brain barrier. Treatment using bone marrow stem cells (BMSC) or retroviruses as vectors reduces the clinical and pathological severity of experimental allergic encephalomyelitis (EAE). We have refined the BMSC based delivery system by introducing a tetracycline sensitive response element to control BDNF expression. We have now tested that construct in EAE and have shown a reduction in both the clinical and pathological severity of the disease. Further, we looked for changes in sirtuin1 and nicotinamide phosphoribosyltransferase expression that would be consistent with a neuroprotective effect.

Cellular stress responses, hormetic phytochemicals and vitagenes in aging and longevity

Modulation of endogenous cellular defense mechanisms represents an innovative approach to therapeutic intervention in diseases causing chronic tissue damage, such as in neurodegeneration. This paper introduces the emerging role of exogenous molecules in hormetic-based neuroprotection and the mitochondrial redox signaling concept of hormesis and its applications to the field of neuroprotection and longevity. Maintenance of optimal long-term health conditions is accomplished by a complex network of longevity assurance processes that are controlled by vitagenes, a group of genes involved in preserving cellular homeostasis during stressful conditions. Vitagenes encode for heat shock proteins (Hsp) Hsp32, Hsp70, the thioredoxin and the sirtuin protein systems. Dietary antioxidants, such as polyphenols and L-carnitine/acetyl-L-carnitine, have recently been demonstrated to be neuroprotective through the activation of hormetic pathways, including vitagenes. Hormesis provides the central underpinning of neuroprotective responses, providing a framework for explaining the common quantitative features of their dose response relationships, their mechanistic foundations, their relationship to the concept of biological plasticity as well as providing a key insight for improving the accuracy of the therapeutic dose of pharmaceutical agents within the highly heterogeneous human population. This paper describes in mechanistic detail how hormetic dose responses are mediated for endogenous cellular defense pathways including sirtuin, Nrfs and related pathways that integrate adaptive stress responses in the prevention of neurodegenerative diseases. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.

Stuck at the bench: Potential natural neuroprotective compounds for concussion

Background:

While numerous laboratory studies have searched for neuroprotective treatment approaches to traumatic brain injury, no therapies have successfully translated from the bench to the bedside. Concussion is a unique form of brain injury, in that the current mainstay of treatment focuses on both physical and cognitive rest. Treatments for concussion are lacking. The concept of neuro-prophylactic compounds or supplements is also an intriguing one, especially as we are learning more about the relationship of numerous sub-concussive blows and/or repetitive concussive impacts and the development of chronic neurodegenerative disease. The use of dietary supplements and herbal remedies has become more common place.

Methods:

A literature search was conducted with the objective of identifying and reviewing the pre-clinical and clinical studies investigating the neuroprotective properties of a few of the more widely known compounds and supplements.

Results:

There are an abundance of pre-clinical studies demonstrating the neuroprotective properties of a variety of these compounds and we review some of those here. While there are an increasing number of well-designed studies investigating the therapeutic potential of these nutraceutical preparations, the clinical evidence is still fairly thin.

Conclusion:

There are encouraging results from laboratory studies demonstrating the multi-mechanistic neuroprotective properties of many naturally occurring compounds. Similarly, there are some intriguing clinical observational studies that potentially suggest both acute and chronic neuroprotective effects. Thus, there is a need for future trials exploring the potential therapeutic benefits of these compounds in the treatment of traumatic brain injury, particularly concussion.

Effects of flavonoids and other polyphenols on inflammation

Flavonoids are a family of polyphenolic compounds which are widespread in nature (vegetables) and are consumed as part of the human diet in significant amounts. There are other types of polyphenols, including, for example, tannins and resveratrol. Flavonoids and related polyphenolic compounds have significant antiinflammatory activity, among others. This short review summarizes the current knowledge on the effects of flavonoids and related polyphenolic compounds on inflammation, with a focus on structural requirements, the mechanisms involved, and pharmacokinetic considerations. Different molecular (cyclooxygenase, lipoxygenase) and cellular targets (macrophages, lymphocytes, epithelial cells, endothelium) have been identified. In addition, many flavonoids display significant antioxidant/radical scavenging properties. There is substantial structural variation in these compounds, which is bound to have an impact on their biological profile, and specifically on their effects on inflammatory conditions. However, in general terms there is substantial consistency in the effects of these compounds despite considerable structural variations. The mechanisms have been studied mainly in myeloid cells, where the predominant effect is an inhibition of NF-κB signaling and the downregulation of the expression of proinflammatory markers. At present there is a gap in knowledge of in vitro and in vivo effects, although the pharmacokinetics of flavonoids has advanced considerably in the last decade. Many flavonoids have been studied for their intestinal antiinflammatory activity which is only logical, since the gastrointestinal tract is naturally exposed to them. However, their potential therapeutic application in inflammation is not restricted to this organ and extends to other sites and conditions, including arthritis, asthma, encephalomyelitis, and atherosclerosis, among others.

Role of Akt-dependent pathway in resveratrol-mediated cardioprotection after trauma-hemorrhage

BACKGROUND

Resveratrol has been shown to have protective effects for patients in shock-like states, and Akt (protein kinase B) is known to play a role in pro-inflammatory events in response to injury. The aim of this study is to determine whether resveratrol provides cardioprotection mediated via an Akt-dependent pathway in trauma-hemorrhaged animals.

METHODS

Male Sprague-Dawley rats underwent trauma-hemorrhage and resuscitation. A single dose of resveratrol (30 mg/kg body weight) with or without a PI3K inhibitor (wortmannin) or vehicle was administered intravenously during the resuscitation. Two hours after either the trauma-hemorrhage or sham operation, the cardiac output, the positive maximal pressure increase of the left ventricle (+dP/dt(max)), and the negative maximal pressure decrease of the left ventricle (-dP/dt(max)) were measured. Cardiac myeloperoxidase (MPO) activity, interleukin (IL)-6, and intercellular adhesion molecule (ICAM)-1 levels, Akt activity, and apoptosis were measured. One-way ANOVA and Tukey's test were used for statistical analysis.

RESULTS

Cardiac output and ± dP/dt(max) decreased significantly after trauma-hemorrhage. Administration of resveratrol significantly improved these cardiac function parameters. Trauma-hemorrhage increased cardiac MPO activity, IL-6 levels, and ICAM-1 levels, and these parameters were significantly improved in the resveratrol-treated rats subjected to trauma-hemorrhage. Although trauma-hemorrhage decreased cardiac Akt phosphorylation (p-Akt), resveratrol treatment following trauma-hemorrhage prevented the same decrease in cardiac p-Akt. The increase in cardiac apoptosis was attenuated in rats that received resveratrol. Co-administration of wortmannin prevented the beneficial effects of resveratrol on the attenuation of pro-inflammatory responses and cardiac injury after trauma-hemorrhage.

CONCLUSION

Resveratrol attenuates cardiac injury following trauma-hemorrhage, which is, at least in part, due to its anti-inflammatory effects via Akt-dependent pathways.

Resveratrol improves neuron protection and functional recovery in rat model of spinal cord injury

Researches on the pathology of spinal cord injury (SCI) have been recently focused on oxidative radicals stress and inflammation associated neuronal apoptosis. Resveratrol, a natural phenolic compound, has been extensively studied and shown a wide variety of health beneficial effects, including prevention of cardiovascular diseases and cancer and neuroprotective activities. However, the study of its potential role in neuroprotection and underlying mechanism in SCI model has been limited. In this study, we investigated the effect of resveratrol on neurologic functions and histopathologic changes after SCI and the mechanism underlying its neuroprotective effects. First, neuronal function after SCI was evaluated with Basso Beattle Bresnahan locomotor rating scale (BBB) and the result showed that injured animals treated with resveratrol showed a significant increase in BBB scores. Further, histopathological alternations were evaluated with HE and Nissl staining, showing a restored neural morphology and an increase of the number of neurons after resveratrol administration. To explore the underlying mechanism, anti-oxidation effect of resveratrol was assessed by measuring superoxide dismutase (SOD) activity and malondialdehyde (MDA) level after SCI. Resveratrol treatment reversed the decrease of SOD activity and increase of MDA level caused by SCI, suggesting its anti-oxidation role in response to the injury. In addition, resveratrol treatment suppressed immunoreactivity and expression of inflammatory cytokines including IL-1β, IL-10, TNF-α, and myeloperoxidase (MPO) after SCI, suggesting an anti-inflammation effect of resveratrol. Finally, resveratrol treatment inhibited injury-induced apoptosis as assessed by electrical microscopy and TUNEL staining and affected the expression level of apoptosis-related gene Bax, Bcl-2 and caspase-3, which indicated its anti-apoptosis role after SCI. Our data suggest that resveratrol significantly promotes the recovery of rat dorsal neuronal function after SCI, and this effect is related to its characteristics of anti-oxidation, anti-inflammation and anti-apoptosis.

Resveratrol attenuates behavioral impairments and reduces cortical and hippocampal loss in a rat controlled cortical impact model of traumatic brain injury

Resveratrol (3,5,4'-trihydroxystilbene) is a plant-derived small molecule that is protective against multiple neurological and systemic insults. To date, no studies have explored the potential for resveratrol to provide behavioral protection in adult animals in the setting of traumatic brain injury (TBI). Using 50 male Sprague-Dawley rats, we employed the controlled cortical impact (CCI) model to ascertain whether post-injury administration of resveratrol would reduce the severity of the well-described cognitive and motor deficits associated with the model. Contusion volumes and hippocampal neuronal numbers were also measured to characterize the tissue and neuronal-sparing properties, respectively, of resveratrol. We found that 100 mg/kg, but not 10 mg/kg, of intraperitoneal resveratrol administered after injury provides significant behavioral protection in rats sustaining CCI. Specifically, rodents treated with 100 mg/kg of resveratrol showed improvements in motor performance (beam balance and beam walking) and testing of visuospatial memory (Morris water maze). Behavioral protection was correlated with significantly reduced contusion volumes, preservation of CA1 and CA3 hippocampal neurons, and protection from overt hippocampal loss as a result of incorporation into the overlying cortical contusion in resveratrol-treated animals. Although the mechanisms by which resveratrol mediates its neuroprotection is unclear, the current study adds to the growing literature identifying resveratrol as a potential therapy for human brain injury.

Resveratrol is neuroprotective because it is not a direct activator of Sirt1-A hypothesis

The plant polyphenol resveratrol (3,5,4'-trihydroxystilbene) has been touted to have multiple health benefits. A commonly cited mechanism of resveratrol action is via the activation of the longevity factor Sir2/Sirt1, whose deacetylase activity on several transcription factors has stress resistance and pro-survival effects. Resveratrol has been shown to be beneficial in various in vitro and in vivo models of central nervous system (CNS) neuron death and degeneration, presumably acting through Sirt1. However, accumulating recent evidence suggests that Sirt1 inhibitors are also neuroprotective. These contradictory results leave us with an apparently irreconcilable paradox. Based on other recent findings that resveratrol also activate AMP-activated protein kinase (AMPK), particularly in neurons, we hypothesize that reseveratrol does not exert its neuroprotective effect via direct Sirt1 activation. In fact, resveratrol is neuroprotective precisely because it does not activate Sirt1 during the acute phase of neuronal cell demise. However, its activation of AMPK may be neuroprotective. Furthermore, resveratrol may indirectly increase Sirt1 activity in recovering or spared cells via AMPK's elevation of NAD levels, which then translates into an overall beneficial outcome. The hypothesis could potentially be tested via selective AMPK silencing in various neuronal death and degeneration models, to see if the neuroprotective effect of resveratrol will be blunted. If proven true, the hypothesis has important ramifications in how reseveratrol, as well as novel Sirt1 activators, may be best used in treatment of CNS injuries and disorders.

The protective effects of resveratrol and L-NAME on visceral organs following aortic clamping

BACKGROUND

This study investigated the effect of temporary occlusion of the aorta on the development of ischemia-reperfusion (I/R) injury of the visceral organs, the optimal timing of administration of resveratrol, and its mechanism of protection via inhibiting nitric oxide (NO) release with an NO synthase inhibitor.

METHODS

Rabbits were divided into seven groups according to the administration period of resveratrol and/or N(G)-nitro-L-arginine methyl ester (L-NAME): control group; group 1, resveratrol during ischemic period; group 2, resveratrol during reperfusion period; group 3, L-NAME during ischemic period; group 4, L-NAME during reperfusion period; group 5, resveratrol during ischemic period and L-NAME during reperfusion period; group 6, L-NAME during ischemic period and resveratrol during reperfusion period. The infrarenal aorta was clamped for 30 min. Blood samples were taken for the biochemical assessment, and organ specimens were taken for pathological assessment at 24hr of reperfusion.

RESULTS

In groups 5 and 6, the renal I/R injury was comparatively milder (I/R injury score 1.04+/-0.29 in control group, 0.25+/-0.17 in group 5, and 0.33+/-0.13 in group 6 [p<0.05]). The I/R injury of bowel was milder in group 5 (I/R injury score 1.8+/-0.80 in control group vs. 0.0+/-0.0 in group 5 [p<0.05]).

CONCLUSION

The protective effects of resveratrol on organs that have high metabolic rate like kidney and bowel was proven histopathologically. It may be beneficial to use different pharmacological medications in different periods of the I/R damage as they represent different characteristics with and without oxygen. The combination of resveratrol and L-NAME against I/R injury appears to be an effective option in the near future.

Vascular action of polyphenols

Dietary patterns are widely recognised as contributors to cardiovascular and cerebrovascular disease. Endothelial function, the elastic properties of large arteries and the magnitude and timing of wave reflections are important determinants of cardiovascular performance. Several epidemiological studies suggest that the regular consumption of foods and beverages rich in flavonoids is associated with a reduction in the risk of several pathological conditions ranging from hypertension to coronary heart disease, stroke and dementia. The impairment of endothelial function is directly related to ageing and an association between decreased cerebral perfusion and dementia has been shown to exist. Cerebral blood flow (CBF) must be maintained to ensure a constant delivery of oxygen and glucose as well as the removal of waste products. Increasing blood flow is one potential way for improving brain function and the prospect for increasing CBF with dietary polyphenols is extremely promising. The major polyphenols shown to have some of these effects in humans are primarily from cocoa, wine, grape seed, berries, tea, tomatoes (polyphenolics and nonpolyphenolics), soy and pomegranate. There has been a significant paradigm shift in polyphenol research during the last decade. This review summarises our current knowledge in this area and points the way for the development of new types of functional foods targeted to brain health through improving vascular health.

Resveratrol: a natural compound with pharmacological potential in neurodegenerative diseases

Resveratrol is a phytoalexin structurally related to stilbenes, which is synthesized in considerable amounts in the skin of grapes, raspberries, mulberries, pistachios and peanuts, and by at least 72 medicinal and edible plant species in response to stress conditions. It was isolated in 1940 and did not maintain much interest for around five decades until its role in treatment of cardiovascular diseases was suggested. To date, resveratrol has been identified as an agent that may be useful to treat cancer, pain, inflammation, tissue injury, and other diseases. However, currently the attention is being focused in analyzing its properties against neurodegenerative diseases and as antiaging compound. It has been reported that resveratrol shows effects in in vitro models of epilepsy, Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and nerve injury. However, evidences in vivo as well as in human beings are still lacking. Thus, further investigations on the pharmacological effects of resveratrol in vivo are necessary before any conclusions on its effects on neurodegenerative diseases can be obtained.

Resveratrol inhibits the activity of equine neutrophil myeloperoxidase by a direct interaction with the enzyme

Resveratrol is a polyphenolic antioxidant present in beverage and food known for its multiple protective effects. We report the inhibitory effects of resveratrol on equine myeloperoxidase (MPO), a hemic peroxidase present in the granules of the neutrophils involved in the inflammatory response. Resveratrol inhibited the production of reactive oxygen species (ROS) by stimulated equine neutrophils by acting as a direct scavenger of the ROS released by the cells but did not modify the degranulation of the stimulated neutrophils as the amounts of released MPO were unchanged. Resveratrol strongly inhibited the chlorination, oxidation, and nitration activities of MPO in a dose-dependent manner. By an original technique of specific immunological extraction followed by enzymatic detection (SIEFED), we demonstrated that resveratrol inhibited the peroxidasic activity of the MPO measured by a direct interaction such as the fixation of resveratrol on the enzyme. The observation of a decrease of the accumulation of compound II suggested that resveratrol acts as an electron donor for MPO reduction.

Viewpoint: mechanisms of action and therapeutic potential of neurohormetic phytochemicals

The nervous system is of fundamental importance in the adaptive (hormesis) responses of organisms to all types of stress, including environmental "toxins". Phytochemicals present in vegetables and fruits are believed to reduce the risk of several major diseases including cardiovascular disease, cancers and neurodegenerative disorders. Although antioxidant properties have been suggested as the basis of health benefits of phytochemicals, emerging findings suggest a quite different mechanism of action. Many phytochemicals normally function as toxins that protect the plants against insects and other damaging organisms. However, at the relatively low doses consumed by humans and other mammals these same "toxic" phytochemicals activate adaptive cellular stress response pathways that can protect the cells against a variety of adverse conditions. Recent findings have elucidated hormetic mechanisms of action of phytochemicals (e.g., resveratrol, curcumin, sulforaphanes and catechins) using cell culture and animal models of neurological disorders. Examples of hormesis pathways activated by phytochemicals include the transcription factor Nrf-2 which activates genes controlled by the antioxidant response element, and histone deacetylases of the sirtuin family and FOXO transcription factors. Such hormetic pathways stimulate the production of antioxidant enzymes, protein chaperones and neurotrophic factors. In several cases neurohormetic phytochemicals have been shown to suppress the disease process in animal models relevant to neurodegenerative disorders such as Alzheimer's and Parkinson's diseases, and can also improve outcome following a stroke. We are currently screening a panel of biopesticides in order to establish hormetic doses, neuroprotective efficacy, mechanisms of action and therapeutic potential as dietary supplements.

Therapeutic Benefit of Intrathecal Injection of Marrow Stromal Cells on Ischemia-Injured Spinal Cord

BACKGROUND

Prophylactic transplantation of marrow stromal cells (MSCs) before spinal cord ischemia has been shown to attenuate neurologic injures. We sought to investigate the therapeutic effect of MSCs on ischemia-injured spinal cord.

METHODS

Marrow stromal cells were expanded in vitro and prelabeled with bromodeoxyuridine. Spinal cord ischemia was induced in rabbits by infrarenal aortic occlusion for 30 minutes. Four groups were enrolled. About 1 x 10(8) MSCs were intrathecally injected 2 hours (group MSC-2h), 24 hours (group MSC-24h), or 48 hours (group MSC-48h) after spinal cord ischemia, respectively. The control group received intrathecal injection of medium alone. Hind-limb motor function was assessed during a 28-day recovery period with Tarlov criteria, and then histologic examination was performed.

RESULTS

Marrow stromal cells still could be found in the spinal cord 4 weeks after transplantation. The capillary density in the ventral gray matter was significantly increased in the three MSC-treated groups (p < 0.01 versus control group, respectively). After a 28-day recovery, marked functional improvement was detected in group MSC-2h (from day 1 to 28, p < 0.05, versus control group, respectively) and group MSC-24h (from day 14 to 28, p < 0.05, versus control group, respectively), but not in group MSC-48h. The number of intact motor neurons was much greater in group MSC-2h (p < 0.05, versus control group).

CONCLUSIONS

Intrathecal injection of MSCs enhances angiogenesis in the host spinal cord and improves the motor functional recovery after spinal cord ischemia. The therapeutic time window is critical for the therapeutic effect of MSCs.