A standardized Hippophae extract (SBL-1) counters neuronal tissue injuries and changes in neurotransmitters: implications in radiation protection.

CONTEXT: Effects of a radioprotective, standardized leaf extract (code SBL-1) from traditional medicinal plant, sea buckthorn [Hippophae rhamnoides L. (Elaeagnaceae)], on neurotransmitters and brain injuries in rats showing radiation-induced conditioned taste aversion (CTA), are not known. Understanding CTA in rats is important because its process is considered parallel to nausea and vomiting in humans. OBJECTIVE: This study investigated the levels of neurotransmitters, antioxidant defences and histological changes in rats showing radiation CTA, and their modification by SBL-1. MATERIALS AND METHODS: The inbred male Sprague-Dawley rats (age 65 days, weighing 190 ± 10 g) were used. Saccharin-preferring rats were selected using standard procedure and divided into groups. Group I (untreated control) was administered sterile water, group II was 60Co-γ-irradiated (2 Gy), and group III was administered SBL-1 before irradiation. Observations were recorded up to day 5. RESULTS: Irradiation (2 Gy) caused (i) non-recoverable CTA (≥ 64.7 ± 5.0%); (ii) degenerative changes in cerebral cortex, amygdala and hippocampus; (iii) increases in brain dopamine (DA, 63.4%), norepinephrine (NE, 157%), epinephrine (E, 233%), plasma NE (103%) and E (160%); and (iv) decreases in brain superoxide dismutase (67%), catalase (60%) and glutathione (51%). SBL-1 treatment (12 mg/kg body weight) 30 min before irradiation (i) countered brain injuries, (ii) reduced CTA (38.7 ± 3.0%, day 1) and (iii) normalized brain DA, NE, E, superoxide dismutase, catalase and CTA from day 3 onwards. DISCUSSION AND CONCLUSION: Radiation CTA was coupled with brain injuries, disturbances in neurotransmitters and antioxidant defences. SBL-1 pretreatment countered these disturbances, indicating neuroprotective action.

Neuroprotective Effects of a Standardized Flavonoid Extract from Safflower against a Rotenone-Induced Rat Model of Parkinson's Disease.

Parkinson's disease (PD) is a major age-related neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra par compacta (SNpc). Rotenone is a neurotoxin that is routinely used to model PD to aid in understanding the mechanisms of neuronal death. Safflower (Carthamus tinctorius. L.) has long been used to treat cerebrovascular diseases in China. This plant contains flavonoids, which have been reported to be effective in models of neurodegenerative disease. We previously reported that kaempferol derivatives from safflower could bind DJ-1, a protein associated with PD, and that a flavonoid extract from safflower exhibited neuroprotective effects in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of PD. In this study, a standardized safflower flavonoid extract (SAFE) was isolated from safflower and found to primarily contain flavonoids. The aim of the current study was to confirm the neuroprotective effects of SAFE in rotenone-induced Parkinson rats. The results showed that SAFE treatment increased body weight and improved rearing behavior and grip strength. SAFE (35 or 70 mg/kg/day) treatment reversed the decreased protein expression of tyrosine hydroxylase, dopamine transporter and DJ-1 and increased the levels of dopamine and its metabolite. In contrast, acetylcholine levels were decreased. SAFE treatment also led to partial inhibition of PD-associated changes in extracellular space diffusion parameters. These changes were detected using a magnetic resonance imaging (MRI) tracer-based method, which provides novel information regarding neuronal loss and astrocyte activation. Thus, our results indicate that SAFE represents a potential therapeutic herbal treatment for PD.

Standardized Bacopa monnieri extract ameliorates acute paraquat-induced oxidative stress, and neurotoxicity in prepubertal mice brain.

OBJECTIVES: Bacopa monnieri (BM), an ayurvedic medicinal plant, has attracted considerable interest owing to its diverse neuropharmacological properties. Epidemiological studies have shown significant correlation between paraquat (PQ) exposure and increased risk for Parkinson's disease in humans. In this study, we examined the propensity of standardized extract of BM to attenuate acute PQ-induced oxidative stress, mitochondrial dysfunctions, and neurotoxicity in the different brain regions of prepubertal mice. METHODS: To test this hypothesis, prepubertal mice provided orally with standardized BM extract (200 mg/kg body weight/day for 4 weeks) were challenged with an acute dose (15 mg/kg body weight, intraperitoneally) of PQ after 3 hours of last dose of extract. Mice were sacrificed after 48 hours of PQ injection, and different brain regions were isolated and subjected to biochemical determinations/quantification of central monoamine (dopamine, DA) levels (by high-performance liquid chromatography). RESULTS: Oral supplementation of BM for 4 weeks resulted in significant reduction in the basal levels of oxidative markers such as reactive oxygen species (ROS), malondialdehyde (MDA), and hydroperoxides (HP) in various brain regions. PQ at the administered dose elicited marked oxidative stress within 48 hours in various brain regions of mice. However, BM prophylaxis significantly improved oxidative homeostasis by restoring PQ-induced ROS, MDA, and HP levels and also by attenuating mitochondrial dysfunction. Interestingly, BM supplementation restored the activities of cholinergic enzymes along with the restoration of striatal DA levels among the PQ-treated mice. DISCUSSION: Based on these findings, we infer that BM prophylaxis renders the brain resistant to PQ-mediated oxidative perturbations and thus may be better exploited as a preventive approach to protect against oxidative-mediated neuronal dysfunctions.

Recommendations for Development of New Standardized Forms of Cocoa Breeds and Cocoa Extract Processing for the Prevention of Alzheimer's Disease: Role of Cocoa in Promotion of Cognitive Resilience and Healthy Brain Aging.

It is currently thought that the lackluster performance of translational paradigms in the prevention of age-related cognitive deteriorative disorders, such as Alzheimer's disease (AD), may be due to the inadequacy of the prevailing approach of targeting only a single mechanism. Age-related cognitive deterioration and certain neurodegenerative disorders, including AD, are characterized by complex relationships between interrelated biological phenotypes. Thus, alternative strategies that simultaneously target multiple underlying mechanisms may represent a more effective approach to prevention, which is a strategic priority of the National Alzheimer's Project Act and the National Institute on Aging. In this review article, we discuss recent strategies designed to clarify the mechanisms by which certain brain-bioavailable, bioactive polyphenols, in particular, flavan-3-ols also known as flavanols, which are highly represented in cocoa extracts, may beneficially influence cognitive deterioration, such as in AD, while promoting healthy brain aging. However, we note that key issues to improve consistency and reproducibility in the development of cocoa extracts as a potential future therapeutic agent requires a better understanding of the cocoa extract sources, their processing, and more standardized testing including brain bioavailability of bioactive metabolites and brain target engagement studies. The ultimate goal of this review is to provide recommendations for future developments of cocoa extracts as a therapeutic agent in AD.

Gaps Between Aims and Achievements in Therapeutic Modification of Neuronal Damage ("Neuroprotection").

The term "neuroprotection" is often misused, overused, or misunderstood. A reasonable definition of neuroprotection refers to the preservation of "neuronal structure and/or function." Although our knowledge about the cellular and molecular mechanisms of neurodegeneration has expanded, experimental systems and animal models that mimic the process or allow translation into clinical success remain limited. This editorial discusses reasons for this gap and strategies to close it. Experimental models can only mirror certain aspects of disease mechanisms in humans. Therefore, findings in these models need to be linked with patient data to improve real-life relevance. Successful neuroprotection depends on finding the right "window of opportunity" which varies from very short (stroke) to very long (Alzheimer's disease), necessitating the need to focus on strategies for very early disease recognition. This need challenges the strategies to be chosen, trial approaches and methodologies, and the allocation of resources. Additionally, outcome measures are often not well suited to assess neuroprotection. To this end, surrogate measures, including biomarkers, are useful endpoints to demonstrate evidence of target directed therapeutic utility. Finally, studies have shown that neuroprotection is not likely to succeed when targeting only one pathway. These obstacles have reduced the level of enthusiasm for neuroprotection in certain disease areas (e.g., stroke). Academia, industry, regulatory authorities, funding agencies and patient organizations have to cooperate to a greater extent in order to overcome these impediments and to encourage nonclassical concepts. These concepts will be interdisciplinary in order to achieve meaningful disease modification.

Evaluation of the neuroprotective effect of minocycline in a rabbit spinal cord ischemia model.

OBJECTIVE: To investigate whether postischemic administration of minocycline attenuates hind-limb motor dysfunction and gray and white matter injuries after spinal cord ischemia. DESIGN: A prospective, randomized, laboratory investigation. SETTING: Laboratory in university, single institution. PARTICIPANTS: Male New Zealand White rabbits. INTERVENTION: Spinal cord ischemia was induced by an occlusion of the infrarenal aorta for 15 minutes. The groups were administered minocycline 1 hour after reperfusion (M-1; n = 8), minocycline 3 hours after reperfusion (M-3; n = 8), saline 1 hour after reperfusion (control [C]; n = 8), or saline and no occlusion (sham; n = 4). Minocycline was administered intravenously at 10 mg/kg 6 times at 12-hour intervals until 60 hours after the initial administration. MEASUREMENT AND MAIN RESULTS: Hind-limb motor function was assessed using the Tarlov score. For histologic assessments, gray and white matter injuries were evaluated 72 hours after reperfusion using the number of normal neurons and the percentage of areas of vacuolation, respectively. Motor function 72 hours after reperfusion was significantly better in group M-1 than in group C. The number of neurons in the anterior horn was significantly larger in group M-1 than in groups M-3 or C but did not differ significantly between groups M-3 and C. No significant difference was noted in the percentage of areas of vacuolation among the ischemia groups. CONCLUSIONS: Minocycline administration beginning at 1 hour after reperfusion improved hind-limb motor dysfunction and attenuated gray matter injury in a rabbit spinal cord ischemia model.

Standardized extracts of Bacopa monniera protect against MPP+- and paraquat-induced toxicity by modulating mitochondrial activities, proteasomal functions, and redox pathways.

Parkinson's disease (PD) is one of the most common age-related neurodegenerative diseases and affects millions of people worldwide. Strong evidence supports the role of free radicals, oxidative stress, mitochondrial, and proteasomal dysfunctions underlying neuronal death in PD. Environmental factors, especially pesticides, represent one of the primary classes of neurotoxic agents associated with PD, and several epidemiological studies have identified the exposure of the herbicide paraquat (PQ) as a potential risk factor for the onset of PD. The objective of our study was to investigate the neuroprotective effects of the standardized extracts of Bacopa monniera (BM) against PQ-induced and 1-methyl-4-phenyl-pyridinium iodide (MPP(+))-induced toxicities and to elucidate the mechanisms underlying this protection. Our results show that a pretreatment with the BM extract from 50 µg/ml protected the dopaminergic SK-N-SH cell line against MPP(+)- and PQ-induced toxicities in various cell survival assays. We demonstrate that BM pretreatment prevented the depletion of glutathione (GSH) besides preserving the mitochondrial membrane potential and maintaining the mitochondrial complex I activity. BM pretreatment from 10.0 µg/ml also prevented the generation of intracellular reactive oxygen species and decreased the mitochondrial superoxide level. BM treatment activated the nuclear factor erythroid 2-related factor 2 pathway by modulating the expression of Keap1, thereby upregulating the endogenous GSH synthesis. The effect of BM on the phosphorylation of Akt further strengthens its role in the promotion of cell survival. By preserving the cellular redox homeostasis and mitochondrial activities and by promoting cell survival pathways, BM extract may have therapeutic uses in various age-related neurodegenerative diseases such as PD.

MRI measures of neuroprotection and repair in multiple sclerosis.

Magnetic resonance imaging (MRI) has had an enormous impact on multiple sclerosis, enabling early diagnosis and providing surrogate markers for monitoring treatment response in clinical trials. Despite these advantages, conventional MRI is limited by lack of pathological specificity and lack of sensitivity to grey matter lesions and to microscopic damage in normal appearing tissue. Quantitative MRI techniques such as measures of parenchymal volume loss, magnetisation transfer imaging, diffusion tensor imaging, and proton magnetic resonance spectroscopy have enhanced our understanding of the nature and mechanism of tissue injury and repair in multiple sclerosis, and provided more specific correlates of neurological deficits and disability accrual. Some of these techniques may be of potential use in clinical trials as surrogate outcome measures for measuring treatment effects on neurodegenerative injury, which is currently difficult to quantify in clinical trials. In this respect, measures of brain volume, T1 hypointensity and magnetisation transfer ratio, and optical coherence tomography appear to be the most promising in the short term. The evidence for a role of neurodegeneration in the pathogenesis of multiple sclerosis, and particularly in the accumulation of irreversible disability, has become increasingly strong over recent years. This has prompted the search for new treatments that can effectively slow down, halt or even reverse such neurodegenerative processes, and in this way restore nervous system function. For this reason, there has been much interest in the development and validation of surrogate markers of neurodegeneration and neuroprotection for use in clinical trials. Advances in magnetic resonance imaging (MRI) technology have allowed the development and implementation of a number of methods that may be promising in this respect. To assess the utility of these methods and to identify needs for further research, sixty experts in neuropathology, clinical measurement, imaging and statistics participated in a meeting held in Amsterdam in 2008 under the aegis of the National Multiple Sclerosis Society. In the proceedings of the meeting, published in 2009 [1], brain volume changes, T1 hypointensity, magnetisation transfer ratio and optical coherence tomography were deemed the most promising measures for screening the neuroprotective capacity of new agents. Other MRI techniques, such as DTI, (1)H-MRS and functional MRI, although potentially useful, require more observational data to help determine the optimal trial design. This article will review some of the issues that were discussed at this meeting, and present some of the imaging techniques that were considered to be the most promising.

In vitro models of neurotrauma.

Traumatic brain injury (TBI) continues to be an important cause of mortality and morbidity, but its pathophysiology is no longer considered an instantaneous irreversible event occurring at the time of injury. Therein, neuroprotection is the attempt to salvage sublethally injured neurons which subsequently die in post-primary sequelae. Key to the discovery of neuroprotective strategies is the development of reliable models of brain injury--both in vivo and in vitro. While numerous studies on in vivo animal models have yielded encouraging results, these have largely failed to translate effectively in humans. One approach out of this impasse may be to re-explore in vitro models to dissect out specific pathophysiological mechanisms and only then test clearer hypotheses on in vivo models, which are more likely to subsequently translate into neuroprotective therapies of the future. Moreover, milder forms of TBI are a more realistic target for therapeutic intervention as more is understood about the vulnerability of surviving neurons and the capacity to salvage them. Several types of injury models are described including transection, compression, barotrauma, acceleration, hydrodynamic and cell stretch models with their advantages and disadvantages discussed in turn, as well as a survey of the cell cultures used, namely immortalized cell lines, primary cultures and organotypic (explant) cultures. We emphasize advances in three-dimensional strain simulation and a recent interest in modelling milder injuries, and argue that in vitro models may be a useful complement to in vivo models in studying TBI.

Protective role of Panax ginseng extract standardized with ginsenoside Rg3 against acrylamide-induced neurotoxicity in rats.

Acrylamide (ACR) is an industrial neurotoxic chemical that has been recently found in carbohydrate-rich foods cooked at high temperatures. ACR was designated as a probable human carcinogen by IARC (1994) and USEPA (1988). Panax ginseng extract has efficacies such as anticancer, antihypertension, antidiabetes and antinociception. The objective of the current study is to evaluate the protective effects of Panax ginseng extract against ACR-induced toxicity in rats. Sixty adult Sprague Dawley female rats were divided into six groups included a control group, a group treated orally with ACR (50 mg kg(-1) body weight; b.w.) for 11 days, a group treated orally with Panax ginseng extract (20 mg kg(-1) b.w.) for 11 days and groups treated orally with Panax ginseng for 11 days before, during or after 11 days of ACR treatment. The results indicated that treatment with ACR alone resulted in a significant increase in lipid peroxidation level and LDH activity in brain homogenate as well as in serum CK activity, whereas it caused a significant decrease in SOD activity and a small but statistically insignificant decrease in Na(+)K(+)-ATPase activity in brain homogenate. Serum serotonin, corticosterone, T3, T4, TSH, estradiol, progesterone and plasma adrenaline were significantly decreased in ACR-treated rats. Treatment with Panax ginseng before, during or after ACR treatment reduced or partially antagonized the effects induced by ACR towards the normal values of controls. It could be concluded that Panax ginseng extract exhibited a protective action against ACR toxicity and it is worth noting that treatment with Panax ginseng extract before or at the same time as ACR treatment was more effective than when administered after ACR treatment.

Protecting the brain: the search for a clinically effective neuroprotective drug for stroke.

The idea that it should be possible to develop a neuroprotective drug that protects the brain from some of the consequences of an acute ischaemic stroke has been in existence for some time and has developed from our increasing knowledge of the biochemical consequences of an acute ischaemic episode. A variety of drugs have been developed to interfere with these biochemical changes. However, while many of these compounds have been shown to be efficacious in animal models of stroke, none has succeeded in clinical trials and reached the market in the Western world. Partly as a result of these failures, guidelines have been published and further extended that detail criteria that should be met before a novel compound is progressed to clinical investigation. These guidelines are reviewed herein, and the author suggests the probability that none of the compounds that have previously failed clinically would have fulfilled the current selection criteria for advancement to clinical trial. It is proposed that NXY-059 (Cerovive) is the first neuroprotective agent to reach the clinical trial phase that meets all the suggested guidelines for neuroprotective drug development, and the preclinical profile of this compound is reviewed.

Effects of the bradykinin antagonist Bradycor (deltibant, CP-1027) in severe traumatic brain injury: results of a multi-center, randomized, placebo-controlled trial. American Brain Injury Consortium Study Group.

A phase II prospective, randomized, double blind clinical trial of Bradycor, a bradykinin antagonist, was conducted at 31 centers within North America in severely brain injured patients. Patients of Glasgow Coma Score (GCS) 3-8 (n = 139) with at least one reactive pupil were randomized to receive either Bradycor, 3 microg/kg/min or placebo as a continuous intravenous infusion for 5 days, with the infusion beginning within 12 h of the injury. The primary objective was to assess the efficacy of a continuous infusion of Bradycor (3.0 mc/kg/min) in preventing elevation of intracranial pressure (ICP). Other efficacy measures included the effect of Bradycor on the Therapy Intensity Level (TIL), mortality, and functional outcome. A secondary objective was to evaluate the safety of Bradycor in patients with severe brain injury. Randomization was carried out according to a computer generated randomization list. Patients were followed for the first 14 days of hospitalization with long-term outcome assessed at 3 and 6 months after injury. During the infusion and while the ICP monitor was in place, ICP measurements were recorded hourly along with blood pressure and heart rate. A modified version of the TIL was used to record therapeutic interventions hourly, while the ICP was being monitored. Outcome was assessed at 3 and 6 months after injury using the Glasgow Outcome Score (GOS). Bradycor was well tolerated in this patient population, and no adverse events were attributable to the compound. Although positive trends were seen for both ICP and TIL in the Bradycor group, these differences analyzed on a daily basis were not significant. However, a mixed model of variance which included treatment, day, treatment by day interaction, age and GCS revealed that the percentage time ICP of >15 mm Hg on days 4 and 5 was significantly lower in the Bradycor group compared to placebo (p = 0.035). There were fewer deaths in the Bradycor group, which had a 28-day all cause mortality of 20% versus 27% on placebo. Patients treated with Bradycor showed a 10.3% improvement in favorable outcome at 3 months and a 12% improvement in dichotomized GOS at 6 months (p = 0.26). The consistent positive trends seen in ICP, TIL, neuropsychological tests, and, most importantly, 3- and 6-month GOS provide supportive evidence that a bradykinin antagonist may play a neuroprotective role in severe brain injury.

Aspirin, anti-inflammatory drugs and risk of dementia.

OBJECTIVE: To test the hypothesis that aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) may prevent dementia or cognitive impairment. DESIGN: A two-wave longitudinal study over 3.6 years. SETTING: A community survey of elderly persons living in Canberra, Australia. PARTICIPANTS: There were 1045 elderly persons aged 70 at the start of the study; cognitive assessment was obtained at both waves on 588. MAIN OUTCOME MEASURES: Cognitive functioning was measured using the Mini-Mental State Examination, an episodic memory test, a test of mental speed and the National Adult Reading Test. Dementia was assessed using the Canberra Interview for the Elderly. RESULTS: On cross-sectional data, those who had been taking NSAIDs or aspirin performed no better on the cognitive tests after account had been taken of other confounding variables. There was no interaction with apolipoprotein E genotype. On longitudinal data, no difference was found between NSAID or aspirin users and controls, either in cognitive decline or incidence of dementia. CONCLUSIONS: The results do not support the hypothesis that aspirin or NSAIDs have a protective effect, but it remains possible that various sources of measurement error may have attenuated an effect of clinical significance from either type of drug. Conclusive evidence can be obtained only by a prospective trial.