A Ginkgo biloba extract (EGb 761) prevents mitochondrial aging by protecting against oxidative stress

Nutritional and exercise-based interventions in the treatment of amyotrophic lateral sclerosis

BACKGROUND & AIMS

Disease pathogenesis in amyotrophic lateral sclerosis (ALS) involves a number of interconnected mechanisms all resulting in the rapid deterioration of motor neurons. The main mechanisms include enhanced free radical production, protein misfolding, aberrant protein aggregation, excitotoxicity, mitochondrial dysfunction, neuroinflammation and apoptosis. The aim of this review is to assess the efficacy of using nutrition- and exercise-related interventions to improve disease outcomes in ALS.

METHODS

Studies involving nutrition or exercise in human and animal models of ALS were reviewed.

RESULTS

Treatments conducted in animal models of ALS have not consistently translated into beneficial results in clinical trials due to poor design, lack of power and short study duration, as well as differences in the genetic backgrounds, treatment dosages and disease pathology between animals and humans. However, vitamin E, folic acid, alpha lipoic acid, lyophilized red wine, coenzyme Q10, epigallocatechin gallate, Ginkgo biloba, melatonin, Cu chelators, and regular low and moderate intensity exercise, as well as treatments with catalase and l-carnitine, hold promise to mitigating the effects of ALS, whereas caloric restriction, malnutrition and high-intensity exercise are contraindicated in this disease model.

CONCLUSIONS

Improved nutritional status is of utmost importance in mitigating the detrimental effects of ALS.

Mitochondrial accumulation of APP and Abeta: significance for Alzheimer disease pathogenesis

Accumulating evidence suggest that alterations in energy metabolism are among the earliest events that occur in the Alzheimer disease (AD) affected brain. Energy consumption is drastically decreased in the AD-affected regions of cerebral cortex and hippocampus pointing towards compromised mitochondrial function of neurons within specific brain regions. This is accompanied by an elevated production of reactive oxygen species contributing to increased rates of neuronal loss in the AD-affected brain regions. In this review, we will discuss the role of mitochondrial function and dysfunction in AD. We will focus on the consequences of amyloid precursor protein and amyloid-β peptide accumulation in mitochondria and their involvement in AD pathogenesis.

Role of mitochondrial oxidative stress to explain the different longevity between genders. Protective effect of estrogens

Females live longer than males. Work from our laboratory has shown that this may be due to the up-regulation of longevity-associated genes by estrogens. Estrogens bind to the estrogen receptors and subsequently activate the mitogen activated protein kinase and nuclear factor kappa B signalling pathways, resulting in an up-regulation of antioxidant enzymes. Estrogen administration, however, has serious undesirable effects and of course, cannot be administered to males because of its powerful feminizing effects. Thus, we tested the effect of genistein, a phytoestrogen of high nutritional importance whose structure is similar to estradiol, on the regulation of the expression of antioxidant, longevity-related genes and consequently on oxidant levels in mammary gland tumour cells in culture. Phytoestrogens mimic the protective effect of oestradiol using the same signalling pathway. The critical importance of up-regulating antioxidant genes, by hormonal and dietary manipulations, to increase longevity is discussed.

Ferritin oxidation and proteasomal degradation: Protection by antioxidants

The accumulation of oxidatively damaged proteins is a well-known hallmark of aging and several neurodegenerative diseases including Alzheimer's, Parkinson's and Huntigton's diseases. These highly oxidized protein aggregates are in general not degradable by the main intracellular proteolytic machinery, the proteasomal system. One possible strategy to reduce the accumulation of such oxidized protein aggregates is the prevention of the formation of oxidized protein derivatives or to reduce the protein oxidation to a degree that can be handled by the proteasome. To do so an antioxidative strategy might be successful. Therefore, we undertook the present study to test whether antioxidants are able to prevent the protein oxidation and to influence the proteasomal degradation of moderate oxidized proteins. As a model protein we choose ferritin. H2O2 induced a concentration dependent increase of protein oxidation accompanied by an increased proteolytic susceptibility. This increase of proteolytic susceptibility is limited to moderate hydrogen peroxide concentrations, whereas higher concentrations are accompanied by protein aggregate formation. Protective effects of the vitamin E derivative Trolox, the pyridoindole derivative Stobadine and of the standardized extracts of flavonoids from bark of Pinus Pinaster Pycnogenol and from leaves of Ginkgo biloba (EGb 761) were studied on moderate damaged ferritin.

Ginkgo biloba: specificity of neuropsychological improvement--a selective review in search of differential effects

Extracts of Ginkgo biloba are widely used for the treatment of cognitive impairment. Whereas reviews have focused on the question whether ginkgo is effective to enhance cognition in general, little is known about specificity of improvement. This might be crucial for future trials, thus enabling hypotheses about sensitive outcome measures. Therefore, this article summarizes such information, i.e. neuropsychological effects of chronic administration of ginkgo in healthy and cognitively impaired subjects of any age. Objective psychometric test results were considered if they reflected distinct cognitive functions from randomized controlled group-studies (RCT). We reviewed 29 RCTs yielding 209 placebo-drug comparisons of psychometric scores in four different cognitive domains comprising 14 sub-functions. Whereas little specific information can be obtained from trials for treatment of dementia, a pattern of pharmacological actions on cognitive processes emerges here from studies for mild cognitive impairment (MCI), depression, multiple sclerosis and healthy young and elderly subjects. There is consistent evidence that chronic administration improves selective attention, some executive processes and long-term memory for verbal and non-verbal material. Further trials should be more comprehensive as there are few data available on some cognitive functions and psychometric flaws in the selection of tests and the interpretation of their results favouring predominantly beta-errors. Thus, though this pattern is encouraging it also asks for a cautious interpretation to date.

Intra-amygdaloid infusion of Ginkgo biloba leaf extract (EGb761) facilitates fear-potentiated startle in rats

RATIONALE

Ginkgo biloba extract, EGb761, is one of the most commonly used herbal supplements throughout Western society. It has been used in the treatment of various common geriatric complaints including short-term memory loss. We showed that acute systemic administration of EGb761 enhanced fear-potentiated startle (FPS) in rats. Little is known about the behavioral effects of centrally administered EGb761 on FPS.

OBJECTIVE

The current study was performed to evaluate the involvement of basolateral nucleus of amygdala (BLA) in the EGb761 facilitation effect on FPS.

METHODS AND RESULT

Male adult SD rats were used. EGb761 was infused into cerebroventricle or basolateral nucleus of amygdala 10 min prior to fear conditioning. Animals were then tested for FPS 24 h later. Results showed that (1) intra-cerebroventricular infusion of EGb761 (0.1, 1.0, or 3.0 microg/3.0 microl per side, bilaterally) and intra-amygdaloid infusion of EGb761 (1.0, 14.0, or 28.0 ng/microl per side, bilaterally) 30 and 10 min prior to fear conditioning, respectively, facilitated FPS in a dose-dependent manner. (2) Administration of EGb761 did not impair an animal's basal startle response or pain perception. (3) Subsequent control experiment's results indicated that the facilitation effect of EGb761 on the acquisition was not due to anxiogenic effect or non-specific effect.

CONCLUSIONS

These results suggested that a single dose of EGb761 also has memory-enhancing effects in young animals. In addition, BLA is the central locus for EGb761 facilitation effect on FPS.

EGb761 protects against nigrostriatal dopaminergic neurotoxicity in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinsonism in mice: role of oxidative stress

1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes nigrostriatal dopaminergic neurotoxicity and behavioral impairment in rodents. Previous studies suggest that oxidative stress, via free radical production, is involved in MPTP-induced neurotoxicity. The MPTP-treated mouse has been the most widely used model for assessing neuroprotective agents for Parkinson's disease. It has been reported previously that EGb761 prevents dopaminergic neurotoxicity of MPTP. This compound is multifunctional via different mechanisms. Here, we report the neuroprotective effect of EGb761 against oxidative stress induced by MPTP in C57BL/6J mice. EGb761 is a patented and well-defined mixture of active compounds extracted from Ginkgo biloba leaves, with neuroprotective effects, exerted probably via its antioxidant or free radical scavenger action. MPTP administration resulted in a significant decrease in striatal dopamine levels and tyrosine hydroxylase immunostaining in the striatum and substantia nigra pars compacta. Mice receiving EGb761 had significantly attenuated MPTP-induced loss of striatal dopamine levels and tyrosine hydroxylase immunostaining in the striatum and substantia nigra pars compacta. The neuroprotective effect of EGb761 against MPTP neurotoxicity is associated with blockade of lipid peroxidation and reduction of superoxide radical production (indicated by a down-regulation of Mn-superoxide dismutase activity), both of which are indices of oxidative stress. Behavioral analyses showed that EGb761 improved MPTP-induced impairment of locomotion in a manner that correlated with enhancement of striatal dopamine levels. These findings suggest that, in mice, EGb761 attenuates MPTP-induced neurodegeneration of the nigrostriatal pathway and that an inhibitory effect against oxidative stress may be partly responsible for its observed neuroprotective effects.

Protective effect of antioxidants against sarcoplasmic reticulum (SR) oxidation by Fenton reaction, however without prevention of Ca-pump activity

The Ca(2+)-ATPase of the sarcoplasmic reticulum (SERCA) of rabbit skeletal muscle was oxidized by Fe2+/H2O2/ascorbic acid (AA), a system which generates HO(.) radicals according to the Fenton reaction: (Fe2(+)+H2O2-->HO(.)+OH(-)+Fe(3+)) under conditions similar to the pathological state of inflammation. Under these conditions, when hydroxyl-radicals and/or ferryl-radicals are generated, a 50% decrease of the SERCA activity was observed, a significant decrease of SH groups and an increase of protein carbonyl groups and lipid peroxidation were identified. Two new bands, time dependent in density, appeared in the SERCA protein electrophoresis after incubation with the Fenton system (at approximately 50 and 75kDa), probably due to structural changes as supported also by trypsin digestion. Immunoblotting of DNPH derivatized protein bound carbonyls detected a time dependent increase after incubation of SERCA with the Fenton system. Trolox and the pyridoindole stobadine (50microM) protected SR against oxidation induced via the Fenton system by preventing SH group oxidation and lipid peroxidation. Pycnogenol((R)) and EGb761 (40microg/ml) protected SERCA in addition against protein bound carbonyl formation. In spite of the antioxidant effects, trolox and stobadine were not able to prevent a decrease in the SERCA Ca(2+)-ATPase activity. Pycnogenol and EGb761 even enhanced the decrease of the Ca(2+)-ATPase activity induced by the Fenton system, probably by secondary oxidative reactions.

Attenuation of senescence-induced oxidative exacerbations in aged rat brain by (-)-epigallocatechin-3-gallate

Aging is a complex biological phenomenon which involves free radicals and oxidative stress. Brain is more susceptible and vulnerable to oxidative damage due to its high-polyunsaturated fatty acid content and high rate of aerobic metabolism. Since the antioxidant defense system is diminished during aging, antioxidant supplementation might be a protective strategy against age-associated oxidative damage. The present study evaluates the antioxidant potential of (-)-epigallocatechin-3-gallate (EGCG), a major polyphenol present in green tea against age-associated oxidative damage in rat brain. Male albino rats of Wistar strain were used in the study. Group I (young) and Group II (aged) rats received saline alone orally for 30 days. Group III (young) and Group IV (aged) rats received EGCG (2mg/kg body weight/day) orally for 30 days. Antioxidant status and oxidative damage were assessed. EGCG brought about an augmentation in the activities of enzymic antioxidants like superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase and improved the non-enzymic antioxidants like tocopherol, ascorbic acid and glutathione. EGCG ameliorated the malondialdehyde and protein carbonyl levels. Thus, EGCG has emerged out as a good antioxidant neutraceutical and a neuroprotective agent in alleviating the age-associated oxidative damage in aged rat brain.

Ginkgo biloba (EGb 761) usage attenuates testicular injury induced by testicular ischemia/reperfusion in rats

INTRODUCTION

We investigated the effect of ginkgo biloba on testicular ischemia-reperfusion (IR) injury.

MATERIALS AND METHODS

Thirty-two Wistar Albino rats were randomly assigned into four groups. Torsion/detorsion (T/D) performed to the rats in group 1, group 2 received ginkgo biloba (50 mg/day) for a month before T/D, group 3 received only gingko biloba (50 mg/day) for a month and group 4 was defined as sham group. After 1 month the testes were removed.

RESULTS

Mean testicular malondialdehyde, nitrate and nitrite levels were significantly increased in group 1 compared to groups 2, 3 and 4 (P<0.05). The rats in group 3 provided basal histological appearance. In group 1, edema, congestion and hemorrhage between seminiferous tubules were predominant. In group 2, histopathologic features were markedly less than group 1.

CONCLUSIONS

Malondialdehyde, nitrate and nitrite levels were increased after unilateral testicular torsion. EGb 761 has a protective effect on testicular injury induced by IR.

Ginkgo biloba extract EGb 761 attenuates hippocampal neuronal loss and cognitive dysfunction resulting from chronic restraint stress in ovariectomized rats

We have recently found that a combination of ovariectomy (OVX) and chronic restraint stress causes cognitive dysfunction and reduces hippocampal CA3 neurons in female rats and that estrogen replacement suppresses the OVX/stress-induced behavioral and morphological changes. In this study, we examined the effect of Ginkgo biloba extract (EGb 761), a popular herbal supplement, on the cognitive dysfunction and neuromorphological change in OVX/stress-subjected rats. Female Fisher 344 rats were randomly divided into three groups: vehicle-treated OVX, EGb 761 (50 mg/kg) -treated OVX and vehicle-treated sham-operated control groups. Two months after ovariectomy, all animals received restraint stress for 21 days (6 h/day), and were then subjected to a novel object recognition test followed by morphological examination by Nissl staining. EGb 761 was orally administered once daily until the behavioral analysis was done. Treatment with EGb 761 improved memory impairment and neuronal loss of hippocampus in the OVX/stress-subjected group in the same ways as 17beta-estradiol. On the other hand, EGb 761 did not affect the loss of bone mineral density and increase in body weight after OVX, although 17beta-estradiol attenuated them. These results have important implications for neuroprotective and cognition enhancing effects of EGb 761 in postmenopausal women and suggest that the effects are mediated by a different mechanism from estrogen.

Mitochondrial dysfunction: the first domino in brain aging and Alzheimer's disease?

With the increasing average life span of humans and with decreasing cognitive function in elderly individuals, age-related cognitive disorders including dementia have become a major health problem in society. Aging-related mitochondrial dysfunction underlies many common neurodegenerative disorders diseases, including Alzheimer's disease (AD). AD is characterized by two major histopathological hallmarks, initially intracellular and with the progression of the disease extracellular accumulation of oligomeric and fibrillar beta-amyloid (Abeta) peptides and intracellular neurofibrillary tangles (NFT) composed of hyperphosphorylated tau protein. In this review, the authors focus on the latest findings in AD animal models indicating that these histopathological alterations induce deficits in the function of the complexes of the respiratory chain and therefore consecutively result in mitochondrial dysfunction. This parameter is intrinsically tied to oxidative stress. Both are early events in aging and especially in the pathogenesis of aging-related severe neurodegeneration. Ginkgo biloba extract seems to be of therapeutic benefit in the treatment of mild to moderate dementia of different etiology, although the data are quite heterogeneous. Herein, the authors suggest that mitochondrial protection and subsequent reduction of oxidative stress are important components of the neuroprotective activity of Ginkgo biloba extract.

From mitochondria to disease: role of the renin-angiotensin system

Mitochondria are energy-producing organelles that conduct other key cellular tasks. Thus, mitochondrial damage may impair various aspects of tissue functioning. Mitochondria generate oxygen- and nitrogen-derived oxidants, being themselves major oxidation targets. Dysfunctional mitochondria seem to contribute to the pathophysiology of hypertension, cardiac failure, the metabolic syndrome, obesity, diabetes mellitus, renal disease, atherosclerosis, and aging. Mitochondrial proteins and metabolic intermediates participate in various cellular processes, apart from their well-known roles in energy metabolism. This emphasizes the participation of dysfunctional mitochondria in disease, notwithstanding that most evidences supporting this concept come from animal and cultured-cell studies. Mitochondrial oxidant production is altered by several factors related to vascular pathophysiology. Among these, angiotensin-II stimulates mitochondrial oxidant release leading to energy metabolism depression. By lowering mitochondrial oxidant production, angiotensin-II inhibition enhances energy production and protects mitochondrial structure. This seems to be one of the mechanisms underlying the benefits of angiotensin-II inhibition in hypertension, diabetes, and aging rodent models. If some of these findings can be reproduced in humans, they would provide a new perspective on the implications that RAS-blockade can offer as a therapeutic strategy. This review intends to present available information pointing to mitochondria as targets for therapeutic Ang-II blockade in human renal and CV disease.

Ginkgo biloba leave extract: biological, medicinal, and toxicological effects

Ginkgo biloba leave extract is among the most widely sold herbal dietary supplements in the United States. Its purported biological effects include: scavenging free radical; lowering oxidative stress; reducing neural damages, reducing platelets aggregation; anti-inflammation; anti-tumor activities; and anti-aging. Clinically, it has been prescribed to treat CNS disorders such as Alzheimer's disease and cognitive deficits. It exerts allergy and changes in bleeding time. While its mutagenicity or carcinogenic activity has not been reported, its components, quercetin, kaempferol and rutin have been shown to be genotoxic. There are no standards or guidelines regulating the constituent components of Ginkgo biloba leave extract nor are exposure limits imposed. Safety evaluation of Ginkgo biloba leave extract is being conducted by the U.S. National Toxicology Program.

The role of mitochondrial DNA mutations in mammalian aging

Mitochondrial DNA (mtDNA) accumulates both base-substitution mutations and deletions with aging in several tissues in mammals. Here, we examine the evidence supporting a causative role for mtDNA mutations in mammalian aging. We describe and compare human diseases and mouse models associated with mitochondrial genome instability. We also discuss potential mechanisms for the generation of these mutations and the means by which they may mediate their pathological consequences. Strategies for slowing the accumulation and attenuating the effects of mtDNA mutations are discussed.

Chronic melatonin treatment prevents age-dependent cardiac mitochondrial dysfunction in senescence-accelerated mice

Heart mitochondria from female senescence-accelerated (SAMP8) and senescence-resistant (SAMR1) mice of 5 or 10 months of age, were studied. Mitochondrial oxidative stress was determined by measuring the levels of lipid peroxidation, glutathione and glutathione disulfide and glutathione peroxidase and reductase activities. Mitochondrial function was assessed by measuring the activity of the respiratory chain complexes and ATP content. The results show that the age-dependent mitochondrial oxidative damage in the heart of SAMP8 mice was accompanied by a reduction in the electron transport chain complex activities and in ATP levels. Chronic melatonin administration between 1 and 10 months of age normalized the redox and the bioenergetic status of the mitochondria and increased ATP levels. The results support the presence of significant mitochondrial oxidative stress in SAM mice at 10 months of age, and they suggest a beneficial effect of chronic pharmacological intervention with melatonin, which reduces the deteriorative and functional oxidative changes in cardiac mitochondria with age.

Extract of Ginkgo biloba EGb761 facilitates extinction of conditioned fear measured by fear-potentiated startle

A standard extract of Ginkgo biloba (EGb761) has been used in the treatment of various common geriatric complaints including vertigo, short-term memory loss, hearing loss, lack of attention, or vigilance. We demonstrated that acute systemic administration of EGb761 facilitated the acquisition of conditioned fear. Many studies suggest the neural mechanism underlies extinction is similar to the acquisition. This raises a possibility that EGb761 may modulate and accelerate the fear extinction process. We tested this possibility by using fear-potentiated startle (FPS) on laboratory rats. Acute systemic injection of EGb761 (10, 20, or 50 mg/kg) 30 min before extinction training facilitated extinction in a dose-dependent manner. Intra-amygdaloid infusion of EGb761 (28 ng/side, bilaterally) 10 min before extinction training also facilitated extinction. Control experiments showed that facilitation effect of EGb761 was not the result of impaired expression of conditioned fear or accelerated forgetting. Rats previously injected with EGb761 showed significant FPS after retraining. Extinction of conditioned fear appeared to result from acute drug effects rather than from toxic action. Systemic administration of EGb761 immediately after extinction training did not facilitate extinction, suggested the EGb761 facilitation effect is contributed to the acquisition phase of extinction learning. Western blot results showed that extinction induced amygdaloid extracellular signal-regulated kinase (ERK1/2) phosphorylation was significantly elevated by EGb761 treatment. Intra-amygdala injection of ERK1/2 inhibitor PD98059 completely blocked the EGb761 effect. Therefore, acute EGb761 administration modulated extinction of conditioned fear by activating ERK1/2.

Evaluation ofBaccharis trimera andDavilla rugosa in tests for adaptogen activity

Baccharis trimera (Asteraceae) and Davilla rugosa (Dilleniaceae) are used popularly as tonics, aphrodisiacs and for stomach ailments, among other uses. Hydroalcohol extracts of the aerial parts of both plants were investigated with regard to their chemical constitution and their pharmacological activity in tests that evaluate adaptogen activity. Alkaloids, flavonoids, saponins, polyphenols/tannins and coumarins were identified in both extracts, while lignans were found only in the extract of Davilla rugosa. This extract presented also a marked antioxidant activity and exerted a moderate antiulcer effect in rats submitted to cold immobilization stress. It did not, however, inhibit the increase in the levels of ACTH and corticosterone induced by stress. Moreover, the Davilla rugosa did not improve the physical performance of mice submitted to forced exercise and the learning time of old rats in the T-maze, neither did it reduce the blood viscosity of the old animals. Conversely, the Baccharis trimera extract only presented a moderate antioxidant activity, without any positive effect on the other tests. These results point to the absence of an adaptogen activity of Baccharis trimera, with some effects that could be related to such an activity as regards the Davilla rugosa.

Simultaneous age-related depolarization of mitochondrial membrane potential and increased mitochondrial reactive oxygen species production correlate with age-related glutamate excitotoxicity in rat hippocampal neurons

Mitochondria are implicated in glutamate excitotoxicity by causing bioenergetic collapse, loss of Ca(2+) homeostasis, and generation of reactive oxygen species (ROS), all of which become increasingly important clinically with age. Little is known about how aging affects the relative importance of mitochondrial membrane potential (DeltaPsi(m)) and ROS production. To determine aging affects on DeltaPsi(m) and ROS production in individual somal and axonal/dendritic mitochondria, we compared ROS production while simultaneously monitoring DeltaPsi(m) before and after glutamate treatment of live neurons from embryonic (day 18), middle-aged (9-12 months), and old (24 months) rats. At rest, old neuronal mitochondria 1) showed a higher rate of ROS production that was particularly strong in axonal/dendritic mitochondria relative to that in middle-age neurons, 2) were more depolarized in comparison with neurons of other ages, and 3) showed no differences in ROS or DeltaPsi(m) as a function of distance from the nucleus. All DeltaPsi(m) grouped into three classes of high (less than -120 mV), medium (-85 to -120 mV), and low (greater than -85 mV) polarization that shifted toward the lower classes with age at rest. Glutamate exposure dramatically depolarized the DeltaPsi(m) in parallel with greatly increased ROS production, with a surprising absence of an effect of age or distance from the nucleus on these mitochondrial parameters. These data suggest that old neurons are more susceptible to glutamate excitotoxicity because of an insidious depolarization of DeltaPsi(m) and rate of ROS generation at rest that lead to catastrophic failure of phosphorylative and reductive energy supplies under stress.

Pentylenetetrazol-induced kindling seizure attenuated by Ginkgo biloba extract (EGb 761) in mice

Ginkgo biloba extract (EGb 761) has been used therapeutically for centuries. It has attracted great attention as agents for improving circulation, particularly cerebral circulation, which may lead to improved mental function. Many researches hypothesized on the role of the extract in the treatment of diseases involving free radicals and oxidative damage. In the present study, anticonvulsant and antioxidant effects of EGb 761 were investigated in pentylenetetrazol (PTZ)-kindled mice. Valproic acid (VA), a major antiepileptic drug, was also tested for comparison. EGb 761-treated mice displayed a significant attenuated response to PTZ on the test day (day 26) compared with saline-treated and VA-treated animals. Valproic acid significantly increased seizure latency. Pretreatments with EGb 761 significantly protected against PTZ-induced convulsive behaviors (seizure latency, seizure score). EGb 761 and VA significantly decreased PTZ-induced oxidative injury in brain tissue. EGb 761 was found to be the most effective in preventing PTZ-induced oxidative damage among both substances studied. The data obtained support our speculation that neuroprotective action of EGb 761 may correlate with its ability to inhibit not only excessive reactive oxygen species (ROS) formation but also seizure generation. Taken together, the results of the present study show that the effect of EGb 761 on ROS production contributes to their neuroprotective action. It might be concluded that the suppression of seizure-induced ROS generation may be involved in the mechanism of action of antiepileptic drugs.

The mitochondrial energy transduction system and the aging process

Aged mammalian tissues show a decreased capacity to produce ATP by oxidative phosphorylation due to dysfunctional mitochondria. The mitochondrial content of rat brain and liver is not reduced in aging and the impairment of mitochondrial function is due to decreased rates of electron transfer by the selectively diminished activities of complexes I and IV. Inner membrane H(+) impermeability and F(1)-ATP synthase activity are only slightly affected by aging. Dysfunctional mitochondria in aged rodents are characterized, besides decreased electron transfer and O(2) uptake, by an increased content of oxidation products of phospholipids, proteins and DNA, a decreased membrane potential, and increased size and fragility. Free radical-mediated oxidations are determining factors of mitochondrial dysfunction and turnover, cell apoptosis, tissue function, and lifespan. Inner membrane enzyme activities, such as those of complexes I and IV and mitochondrial nitric oxide synthase, decrease upon aging and afford aging markers. The activities of these three enzymes in mice brain are linearly correlated with neurological performance, as determined by the tightrope and the T-maze tests. The same enzymatic activities correlated positively with mice survival and negatively with the mitochondrial content of lipid and protein oxidation products. Conditions that increase survival, as vitamin E dietary supplementation, caloric restriction, high spontaneous neurological activity, and moderate physical exercise, ameliorate mitochondrial dysfunction in aged brain and liver. The pleiotropic signaling of mitochondrial H(2)O(2) and nitric oxide diffusion to the cytosol seems modified in aged animals and to contribute to the decreased mitochondrial biogenesis in old animals.

Normal brain ageing: models and mechanisms

Normal ageing is associated with a degree of decline in a number of cognitive functions. Apart from the issues raised by the current attempts to expand the lifespan, understanding the mechanisms and the detailed metabolic interactions involved in the process of normal neuronal ageing continues to be a challenge. One model, supported by a significant amount of experimental evidence, views the cellular ageing as a metabolic state characterized by an altered function of the metabolic triad: mitochondria-reactive oxygen species (ROS)-intracellular Ca2+. The perturbation in the relationship between the members of this metabolic triad generate a state of decreased homeostatic reserve, in which the aged neurons could maintain adequate function during normal activity, as demonstrated by the fact that normal ageing is not associated with widespread neuronal loss, but become increasingly vulnerable to the effects of excessive metabolic loads, usually associated with trauma, ischaemia or neurodegenerative processes. This review will concentrate on some of the evidence showing altered mitochondrial function with ageing and also discuss some of the functional consequences that would result from such events, such as alterations in mitochondrial Ca2+ homeostasis, ATP production and generation of ROS.

Protective effect of Ginkgo biloba leaf extract on learning and memory deficit induced by aluminum in model rats

OBJECTIVE

To examine the protective effect of Ginkgo biloba leaf extract (GbE) on learning and memory deficit induced by aluminum chloride (AlCl(3)), and explore its mechanisms.

METHODS

The rat models with learning and memory deficit were induced by administering via gastrogavage and drinking of AlCl(3) solution. And the model rats were treated with GbE at the dose of 50, 100, 200 mg/kg every day for 2 months accompanied with drinking of AlCl(3) solution, respectively. Their abilities of spatial learning and memory were tested by Morris water maze, and the acetylcholinesterase (AChE) activity in serum was assayed with chemical method, the AChE expression in hippocampus was observed by immunohistochemistry assay, and then quantitative analysis was done by BI 2000 image analysis system.

RESULTS

Learning and memory deficit of rats could be induced by AlCl(3) solution (P < 0.01), and AChE expressions in rats hippocampus were increased (P < 0.01); GbE ameliorated learning and memory deficit and reduced AChE expression in rats hippocampus in a dose-dependent manner, while GbE significantly increased serum AChE activity at the dose of 200 mg/kg each day (P < 0.05).

CONCLUSION

GbE can ameliorate learning and memory deficit induced by AlCl(3), which may be due to its inhibition of the AChE expression in hippocampus.

You say lipofuscin, we say ceroid: defining autofluorescent storage material

Accumulation of intracellular autofluorescent material or "aging pigment" has been characterized as a normal aging event. Certain diseases also exhibit a similar accumulation of intracellular autofluorescent material. However, autofluorescent storage material associated with aging and disease has distinct characteristics. Lipofuscin is a common term for aging pigments, whereas ceroid is used to describe pathologically derived storage material, for example, in the neuronal ceroid lipofuscinoses (NCLs). NCLs are a family of neurodegenerative diseases that are characterized by an accumulation of autofluorescent storage material (ceroid) in the lysosome, which has been termed "lipofuscin-like". There have been many studies that describe this autofluorescent storage material, but what is it? Is this accumulation lipofuscin or ceroid? In this review we will try to answer the following questions: (1) What is lipofuscin and ceroid? (2) What contributes to the accumulation of this storage material in one or the other? (3) Does this material have an effect on cellular function? Studying parallels between the accumulation of lipofuscin and ceroid may provide insight into the biological relevance of these phenomena.

Primary study on the application of Serum Pharmacology in Chinese traditional medicine

In the paper, two main methods, which are Serum Pharmacology and Traditional Pharmacology, were adopted to study Chinese traditional medicine, such as Ginkgo biloba extract (GBE), ginsenosides (GS) and compound GG (GBE+GS), pharmacology in vitro. The results showed that there were evident difference between the results of Serum Pharmacology and that of Traditional Pharmacology. There was no significant difference between the drug effect of crude GS on nitric oxide (NO) production in ECV304 and that of crude GBE, and the drug effect of GG was superior to that of GS and GBE, respectively. But, compared with GBE serum, the GS serum up-regulation of NO production in ECV304 increased significantly, and the GG serum up-regulation of the NO production in ECV304 was inferior to that of GS serum and GBE serum significantly. The results suggested that Serum Pharmacological study should be adopted in the pharmacological investigation on the Chinese traditional medicine and the drug screening of the Chinese traditional medicine.

Effect of antioxidant-enriched diets on glutathione redox status in tissue homogenates and mitochondria of the senescence-accelerated mouse

The main purpose of this study was to investigate whether consumption of diets enriched in antioxidants attenuates the level of oxidative stress in the senescence-accelerated mouse (SAM). In separate and independent studies, two different dietary mixtures, one enriched with vitamin E, vitamin C, L-carnitine, and lipoic acid (Diet I) and another diet including vitamins E and C and 13 additional ingredients containing micronutrients with bioflavonoids, polyphenols, and carotenoids (Diet II), were fed for 8 and 10 months, respectively. The amounts of glutathione (GSH) and glutathione disulfides (GSSG) and GSH:GSSG ratios were determined in plasma, tissue homogenates, and mitochondria isolated from five different tissues of SAM (P8) mice. Both diets had a reductive effect in plasma; however Diet I had relatively little effect on the glutathione redox status in tissue homogenates or mitochondria. Remarkably, Diet II caused a large increase in the amount of glutathione and a marked reductive shift in glutathione redox state in mitochondria. Overall, the effects of Diet II were tissue and gender specific. Results indicated that the glutathione redox state in mitochondria and tissues can be altered by supplemental intake of a relatively complex mixture of dietary antioxidants that contains substances known to induce phase 2 enzymes, glutathione, and antioxidant defenses. Whether corresponding attenuations occur in age-associated deleterious changes in physiological functions or life span remains unknown.

Why females live longer than males: control of longevity by sex hormones

Females live longer than males in many species, including humans. We have traced a possible explanation for this phenomenon to the beneficial action of estrogens, which bind to estrogen receptors and increase the expression of longevity-associated genes, including those encoding the antioxidant enzymes superoxide dismutase and glutathione peroxidase. As a result, mitochondria from females produce fewer reactive oxygen species than those from males. Administering estrogens has serious drawbacks, however--they are feminizing (and thus cannot be administered to males) and may increase the incidence of serious diseases such as uterine cancer in postmenopausal women. Phytoestrogens, which are present in soy or wine, may have some of the favorable effects of estrogens without their undesirable effects. Study of gender differences in longevity may help us to understand the basic processes of aging and to devise practical strategies to increase the longevity of both females and males.

Radioprotection by plant products: present status and future prospects

The development of radioprotective agents has been the subject of intense research in view of their potential for use within a radiation environment, such as space exploration, radiotherapy and even nuclear war. However, no ideal, safe synthetic radioprotectors are available to date, so the search for alternative sources, including plants, has been on going for several decades. In Ayurveda, the traditional Indian system of medicine, several plants have been used to treat free radical-mediated ailments and, therefore, it is logical to expect that such plants may also render some protection against radiation damage. A systematic screening approach can provide leads to identifying potential new candidate drugs from plant sources, for mitigation of radiation injury. This article reviews some of the most promising plants, and their bioactive principles, that are widely used in traditional systems of medicine, and which have rendered significant radioprotection in both in vitro and in vivo model systems. Plants and their constituents with pharmacological activities that may be relevant to amelioration of radiation-mediated damage, including antiemetic, antiinflammatory, antioxidant, cell proliferative, wound healing and haemopoietic stimulatories are also discussed.

Differential cognitive effects of Ginkgo biloba after acute and chronic treatment in healthy young volunteers

RATIONALE

Acute doses of Ginkgo biloba have been shown to improve attention and memory in young, healthy participants, but there has been a lack of investigation into possible effects on executive function. In addition, only one study has investigated the effects of chronic treatment in young volunteers.

OBJECTIVES

This study was conducted to compare the effects of ginkgo after acute and chronic treatment on tests of attention, memory and executive function in healthy university students.

METHODS

Using a placebo-controlled double-blind design, in experiment 1, 52 students were randomly allocated to receive a single dose of ginkgo (120 mg, n=26) or placebo (n=26), and were tested 4 h later. In experiment 2, 40 students were randomly allocated to receive ginkgo (120 mg/day; n=20) or placebo (n=20) for a 6-week period and were tested at baseline and after 6 weeks of treatment. In both experiments, participants underwent tests of sustained attention, episodic and working memory, mental flexibility and planning, and completed mood rating scales.

RESULTS

The acute dose of ginkgo significantly improved performance on the sustained-attention task and pattern-recognition memory task; however, there were no effects on working memory, planning, mental flexibility or mood. After 6 weeks of treatment, there were no significant effects of ginkgo on mood or any of the cognitive tests.

CONCLUSIONS

In line with the literature, after acute administration ginkgo improved performance in tests of attention and memory. However, there were no effects after 6 weeks, suggesting that tolerance develops to the effects in young, healthy participants.

Why females live longer than males? Importance of the upregulation of longevity-associated genes by oestrogenic compounds

Females live longer than males in many mammalian species, including humans. Mitochondria from females produce approximately half the amount of H(2)O(2) than males. We have found that females behave as double transgenics overexpressing both superoxide dismutase and glutathione peroxidase. This is due to oestrogens that act by binding to the estrogen receptors and subsequently activating the mitogen activated protein (MAP) kinase and nuclear factor kappa B (NF-kappaB) signalling pathways. Phytoestrogens mimic the protective effect of oestradiol using the same signalling pathway. The critical importance of upregulating antioxidant genes, by hormonal and dietary manipulations, in order to increase longevity is discussed.

Limited cognitive benefits in Stage +2 postmenopausal women after 6 weeks of treatment with Ginkgo biloba

Gingko biloba has cognitive benefits both in populations suffering from dementia and after acute treatment in healthy volunteers, with some evidence indicating that those with poorer cognitive performance show greater benefit. We have previously found that 1 week of treatment with ginkgo improved attention, memory and mental flexibility in post-menopausal women, but the evidence for any beneficial effects of longer treatment is less well-established. The present study aimed to determine whether cognitive benefits, similar to those previously found after 1 week of treatment, would persist after 6 weeks of treatment, and whether those with poorer cognitive performance would benefit more. In a placebo-controlled, double-blind study, postmenopausal women (aged 51-67 years) were randomly allocated to receive a standardized extract of ginkgo (LI 1370, Lichtwer Pharma, Marlow, UK) (one capsule/day of 120 mg, n = 45) or matching placebo (n = 42) for 6 weeks. According to an established reproductive staging system, subjects were divided into those in the early (Stage +1; mean age 55 years) and late (Stage +2: mean age 61 years) stages of menopause. At baseline and after 6 weeks of treatment, subjects completed tests of mental flexibility, planning, memory and sustained attention, and ratings of mood, sleepiness, bodily and menopausal symptoms. The only significant effects of ginkgo were in the test of mental flexibility, in which there were significant menopausal stage-ginkgo interactions. This was because subjects in Stage +2 required fewer trials to complete the task and made fewer errors after ginkgo treatment, whereas those in Stage +1 showed no benefits. Subjects in Stage +2 had poorer performance at baseline compared to those in Stage +1 both in this task and the test of planning ability. The beneficial effects of ginkgo were limited to the test of mental flexibility and to those with poorer performance.

Protective effects of Ginkgo biloba leaf extract on aluminum-induced brain dysfunction in rats

This study examined the protective effects of Ginkgo biloba extract (GbE) on the learning and memory function in aluminum-treated rats and potential mechanisms. Wistar rats were given daily aluminum chloride 500 mg/kg, i.g, for one month, followed by continuous exposure via the drinking water containing 1600 ppm aluminum chloride for up to 5 months. The ability of spatial learning and memory was tested by Morris water maze. Aluminum administration significantly increased escape latency and searching distance, indicative of brain dysfunction. GbE treatment (50-200 mg/kg, i.g) significantly protected against aluminum-induced brain dysfunction, as evidenced by decreased escape latency and searching distance compared with the Al alone group. To examine the mechanisms of the protection, the expressions of amyloid precursor protein (APP) and caspase-3 in brain regions were examined by immunohistochemistry. GbE treatment reduced the contents of APP and caspase-3 in hippocampus of aluminum-treated rats in a dose-dependent manner. At the highest dose of GbE (200 mg/kg), the immunostain for APP and caspase-3 was returned to normal levels. In summary, this study demonstrates that GbE is effective in improving the ability of spatial learning and memory of aluminum-intoxicated rats. This protection appears to be due to a decreased expression of APP and caspase-3 in rat brain, resulting in a decrease in the production of insoluble fragments of Abeta-amyloid.

Antioxidants prevented oxidative injury of SR induced by Fe2+/H2O2/ascorbate system but failed to prevent Ca2+-ATPase activity decrease

Dysfunction of sarcoplasmic reticulum (SR) Ca2+-ATPase induced by oxidative stress may be a contributing factor to the development of serious age related diseases. Incubation of sarcoplasmic reticulum (SR) vesicles of rabbit skeletal muscles with Fe2+/H2O2/ascorbate decreased the SH group content of SR approximately to 35% and Ca2+-ATPase activity to 50% of control not oxidized sample. Protein carbonyls increased twofold, lipid peroxidation was also significantly elevated. The antioxidant effects of trolox, the pyridoindole derivative stobadine and of the standardized extracts from bark of Pinus Pinaster PycnogenolR (Pyc) and from leaves of Ginkgo biloba (EGb 761) were studied on oxidatively injured SR. All antioxidants exerted preventive effects against the oxidized lipids and protein SH groups of SR vesicles. Trolox and stobadine did not influence protein carbonyl formation, while flavonoid extracts prevented carbonyl generation, probably by binding to protein. The preventive effects of the antioxidants studied on lipids and protein SH groups were however not associated with protection of Ca2+-ATPase activity. Stobadine and trolox exerted no effect on enzyme activity, Pyc and EGb 761 enhanced the inhibitory effect of Ca2+-ATPase activity in oxidatively injured SR. Concluding, under the conditions of oxidative stress induced by Fe2+/H2O2/ascorbate against SR of rabbit skeletal muscle, the agents studied demonstrated antioxidant effects yet failed to protect Ca2+-ATPase activity.

Herbs and the kidney

The use of herbal therapy has increased dramatically in past years and may lead to renal injury or various toxic insults, especially in renal patients. In most countries, herbal products are not regulated as medicines. Herbal poisoning may be secondary to the presence of undisclosed drugs or heavy metals, interaction with the pharmacokinetic profile of concomitantly administered drugs, or association with a misidentified herbal species. Various renal syndromes were reported after the use of medicinal plants, including tubular necrosis, acute interstitial nephritis, Fanconi's syndrome, hypokalemia or hyperkalemia, hypertension, papillary necrosis, chronic interstitial nephritis, nephrolithiasis, urinary retention, and cancer of the urinary tract. It seems critical that caregivers be aware of the potential risk of such often underreported therapy and carefully question their patients about their use of this popular branch of alternative medicine.

Mitochondrial enzyme activities as biochemical markers of aging

The decrease of neurological performance in normal aging is directly related to brain oxidative stress and inversely related to lifespan. Male mice lifespan was increased by 8-10% (median and maximal lifespan, respectively) in mice with high spontaneous neurological activity, by 21-15% after moderate exercise; and by 25-20% after supplementation with vitamin E. Oxidative stress markers, TBARS and protein carbonyl content, were found increased on aging; a higher content of oxidation products is considered an effective aging factor, specially in the brain, with a majority of postmitotic cells. Mitochondrial enzyme activities, mitochondrial nitric oxide synthase (mtNOS), NADH dehydrogenase and cytochrome oxidase, behaved as markers of brain aging. The decrease in enzyme activities was directly related to the content of oxidation products and to the loss of neurological function in aged mice, this latter was determined in the tighrope and the T-maze tests. The above mentioned conditions that increased mice lifespan were effective to decrease the level of oxidative stress markers, and to retard the decreases in mitochondrial enzyme activities and neurological function associated to aging. The activities of mtNOS, NADH dehydrogenase and cytochrome oxidase may be used as indicators of the effectiveness of antiaging treatments.

Concerted action of the renin-angiotensin system, mitochondria, and antioxidant defenses in aging

Angiotensin-converting enzyme inhibitors (ACEi) and AT-1 receptor blockers (ARB) are two types of drugs that inhibit the renin-angiotensin system (RAS), and can attenuate the progression to cardiac and/or renal functional impairment, secondary to diverse pathologies. Some of the beneficial effects of ACEi and ARB occur independently of the ability of these drugs to reduce arterial blood pressure. Both, in animals, and in humans, we observed an enhancement of antioxidant defenses that occurred after treatment with ACEi. Based on these results, we postulate that some of the beneficial health effects associated to RAS inhibition can be ascribed to the prevention of oxidant-mediated damage. Furthermore, considering that: (i). RAS inhibition attenuates certain age-associated degenerative changes; (ii). aging was postulated to result from the accumulation of oxidant-mediated damage; and (iii). mitochondria are a major source of oxidants, we studied potential associations among RAS inhibition, mitochondrial function and production of oxidants and nitric oxide, and aging. The results obtained suggest, that RAS inhibitors, i.e. enalapril and losartan, can protect against the effects of aging by attenuating oxidant damage to mitochondria, and in consequence, they preserve mitochondrial function. The mechanism(s) explaining such attenuation of oxidant damage can relay on a reduction of the ANG-II-dependent generation of superoxide and/or an increased detoxification of reactive nitrogen and oxygen species by recomposition of antioxidant defense levels.

Rat brain and liver mitochondria develop oxidative stress and lose enzymatic activities on aging

The mitochondrial mass of rat brain and liver remained unchanged on aging in young adults, old adults, and senescent animals (28, 60, and 92 wk of age); the values were 15-17 and 29-31 mg protein/g for brain and liver, respectively. The whole aging process was associated with an increased content of the oxidation products, thiobarbituric acid-reactive substances and protein carbonyls, by 61-69% in brain and 36-45% in liver, respectively. The activities of critical enzymes for mitochondrial function, mitochondrial nitric oxide synthase, Mn-superoxide dismutase, complex I, and complex IV, decreased progressively during aging with activity losses of 73, 37, 29, and 28%, respectively, in the brain and 47, 46, 30, and 24% in the liver of senescent rats compared with young adults. Brain mitochondria isolated from aged rats showed increased mitochondrial fragility, as assayed by mitochondrial marker enzyme activities in the postmitochondrial supernatant, and increased volume and water permeability, as assayed by light scattering. Liver mitochondria isolated from young and old rats did not show differences in fragility and water permeability. A subpopulation of brain mitochondria with increased size and fragility was differentiated in aging rats, whereas liver showed a homogeneous mitochondrial population.

The effect of Ginkgo extract EGb761 in cisplatin-induced peripheral neuropathy in mice

Neuroprotective effect of Ginkgo biloba extract EGb761 in cisplatin (cis-diamminedi-chloroplatinum, or CDDP)-induced peripheral neuropathy was investigated. Swiss albino mice were treated with CDDP, 2 mg/kg ip twice a week for nine times. One group of the animals also received EGb761 in the drinking water at an estimated dosage of 100 mg/kg per day. Two other groups received vehicle (control) or EGb761 only. Development of neuropathy was evaluated with changes in sensory nerve conduction velocity (NCV). Following the treatments, dorsal root ganglia (DRGs) were microscopically examined and some were cultured for 3 days. EGb761 proved effective in preventing the reduction in NCV (P < 0.0001) caused by CDDP. CDDP caused a decrease in the number of migrating cells (P < 0.01) and in the length of outgrowing axons (P < 0.01) while EGb761 treatment prevented the latter. CDDP led to smaller nuclear and somatic sizes in neurons (P < 0.01), while with EGb761 co-administration, both were close to control values. Animals having EGb761 only had similar results with controls. In conclusion, EGb761 was found to be effective in preventing some functional and morphological deteriorations in CDDP-induced peripheral neuropathy.

Prevention of age-related spatial memory deficits in a transgenic mouse model of Alzheimer's disease by chronic Ginkgo biloba treatment

Alzheimer's disease (AD) is characterized by cognitive decline and deposition of beta-amyloid (Abeta) plaques in cortex and hippocampus. A transgenic mouse AD model (Tg2576) that overexpresses a mutant form of human Abeta precursor protein exhibits age-related cognitive deficits, Abeta plaque deposition, and oxidative damage in the brain. We tested the ability of Ginkgo biloba, a flavonoid-rich antioxidant, to antagonize the age-related behavioral impairment and neuropathology exhibited by Tg2576 mice. At 8 months of age, 16 female Tg2576 and 15 female wild-type (wt) littermate mice were given ad lib access to tap water or Ginkgo biloba (70 mg/kg/day in water). After 6 months of treatment, all mice received Morris water maze training (4 trials/day for 10 days) to assess hippocampal dependent spatial learning. All mice received a 60-s probe test of spatial memory retention 24 h after the 40th trial. Untreated Tg2576 mice exhibited a spatial learning impairment, relative to wt mice, while Ginkgo biloba-treated Tg2576 mice exhibited spatial memory retention comparable to wt during the probe test. Spatial learning was not different between Ginkgo biloba-treated and untreated wt mice. There were no group differences in learning to swim to a visible platform. Soluble Abeta and hippocampal Abeta plaque burden did not differ between the Tg2576 groups. Brain levels of protein carbonyls were paradoxically elevated in Ginkgo biloba-treated mice. These data indicate that chronic Ginkgo biloba treatment can block an age-dependent decline in spatial cognition without altering Abeta levels and without suppressing protein oxidation in a transgenic mouse model of AD.

Mitochondrial theory of aging: importance to explain why females live longer than males

Females live longer than males in many species, including humans. This can be explained on the basis of the mitochondrial theory of aging. Mitochondria from females produce significantly less hydrogen peroxide than those from males and have higher levels of mitochondrial reduced glutathione, manganese superoxide dismutase, and glutathione peroxidase than males. Oxidative damage to mitochondrial DNA is also fourfold higher in males than in females. These differences may be explained by estrogens. Ovariectomy abolishes the gender differences between males and females and estrogen replacement rescues the ovariectomy effect. The challenge for the future is to find molecules that have the beneficial effects of estradiol, but without its feminizing effects. Phytoestrogens or phytoestrogen-related molecules may be good candidates to meet this challenge.

Ginkgo biloba extract inhibits tumor necrosis factor-alpha-induced reactive oxygen species generation, transcription factor activation, and cell adhesion molecule expression in human aortic endothelial cells

OBJECTIVE

This study was conducted to examination whether Ginkgo biloba extract (GBE), a Chinese herb with antioxidant activity, could reduce cytokine-induced monocyte/human aortic endothelial cell (HAEC) interaction, a pivotal early event in atherogenesis.

METHODS AND RESULTS

Pretreatment of HAECs with GBE (50 and 100 microg/mL for 18 hours) significantly suppressed cellular binding between the human monocytic cell line U937 and tumor necrosis factor-alpha (TNF-alpha)-stimulated HAECs by using in vitro binding assay (68.7% and 60.1% inhibitions, respectively). Cell enzyme-linked immunosorbent assay and immunoblot analysis showed that GBE (50 microg/mL for 18 hours) significantly attenuated TNF-alpha-induced cell surface and total protein expression of vascular cellular adhesion molecule-1 and intracellular adhesion molecule-1 (63.5% and 69.2%, respectively; P<0.05). However, pretreatment with probucol (5 micromol/L for 18 hours) reduced the expression of vascular cellular adhesion molecule-1 but not intracellular adhesion molecule-1. Preincubation of HAECs with GBE or probucol significantly reduced intracellular reactive oxygen species formation induced by TNF-alpha (76.8% and 68.2% inhibitions, respectively; P<0.05). Electrophoretic mobility shift assay demonstrated that both GBE and probucol inhibited transcription factor nuclear factor-kappaB activation in TNF-alpha-stimulated HAECs (55.2% and 65.6% inhibitions, respectively) but only GBE could inhibit the TNF-alpha-stimulated activator protein 1 activation (45.1% inhibition, P<0.05).

CONCLUSIONS

GBE could reduce cytokine-stimulated endothelial adhesiveness by downregulating intracellular reactive oxygen species formation, nuclear factor-kappaB and activator protein 1 activation, and adhesion molecule expression in HAECs, supporting the notion that the natural compound Ginkgo biloba may have potential implications in clinical atherosclerosis disease.

Enalapril and losartan attenuate mitochondrial dysfunction in aged rats

Renin-angiotensin system (RAS) inhibition can attenuate the effects of aging on renal function and structure; however, its effect on mitochondrial aging is unknown. To investigate whether an angiotensin-converting enzyme inhibitor (enalapril) or an angiotensin II receptor blocker (losartan) could mitigate age-associated changes in kidney mitochondria, male Wistar rats (14 mo old) received during 8 mo water containing either enalapril (10 mg/kg/day) (Enal), or losartan (30 mg/kg/day) (Los), or no additions (Old). Four-month-old untreated rats (Young) were also studied. In Old rats mitochondrial respiratory control, ADP/O, nitric oxide synthase activity, and uncoupling protein 2 levels were lower (46, 42, 27, and 76%, respectively), and Mn-SOD activity was higher (70%) than in Young, Enal, and Los rats. In Old rats mitochondrial hydrogen peroxide production was higher than in both Young (197%) and Enal or Los (40%) rats. In Old rats, kidney GSH/GSSG was lower than in both Young (80%) and Enal (57%) or Los (68%) rats. In Old rats electron microscopy showed effacement of microvilli in tubular epithelial cells, ill-defined mitochondrial cristae, lower mitochondrial numbers, and enhanced number of osmiophilic bodies relative to Young, Enal, or Los rats. In conclusion, enalapril and losartan can protect against both age-related mitochondrial dysfunction and ultrastructural alterations, underscoring the role of RAS in the aging process. An association with oxidative stress modulation is suggested.

The collagenolytic effects of the traditional Chinese medicine preparation, Han-Dan-Gan-Le, contribute to reversal of chemical-induced liver fibrosis in rats

Han-Dan-Gan-Le (HDGL), a Chinese herb preparation composed of Stephaniat tetrandra, Salvia miltorrhiza, Radix paeoniae, Astragalus membranaceus, and Ginkgo biloba, has been used to treat human liver fibrosis. This study was designed to examine the therapeutic effect of HDGL on chemical-induced liver fibrosis in adult Wistar rats. Liver fibrosis was produced in rats by carbon tetrachloride (1.2 ml CCl(4)/kg, 2 times/week, after an initial dose of 5.0 ml CCl(4)/kg, sc), plus a diet of 20% fat, 0.05% cholesterol (continuous) and 30% alcohol in the drinking water ad libitum (every other day) for 8 weeks. HDGL (0.5 and 1.0 g/kg, ig, daily for 6 weeks) was administered to rats 72 hrs after the last dose of CCl(4) to examine its therapeutic effects on chemical-induced liver fibrosis. Upon pathological examination, the HDGL treatment had significantly reversed chemical-induced liver fibrosis and other hepatic lesions. Hepatic collagen accumulation induced by CCl(4) was markedly reduced by HDGL treatment, as evidenced by hepatic collagen content and by immunohistochemical analysis of type-I collagen in liver. HDGL appeared to stimulate the collagenolytic process in the liver, as a 30-50% increase in urinary excretion of hydroxyproline was observed with HDGL treatment as compared to rats only given CCl(4). In conclusion, HDGL can effectively reverse chemically induced liver fibrosis, and this appears to be due, at least in part, to the stimulation of hepatic collagenolysis, resulting in a resolution of hepatic fibrosis.

Inverse correlation between mitochondrial size and metabolic competence: a quantitative cytochemical study of cytochrome oxidase activity

Mitochondria are topologically closed bilayered systems where the synthesis of adenosine triphosphate (ATP) from adenosine diphosphate (ADP) and inorganic phosphate occurs via oxidative phosphorylation. The ordered architecture (and its extension) of the mitochondria (i.e. inner membrane, outer membrane and cristae) constitutes a critical topographic arrangement for their energy-providing mechanisms. Thus, quantitative estimations of the ultrastructural features of organelles preferentially stained by means of function-related cytochemical reactions reliably report on their potential to supply adequate amounts of ATP. On the basis of this rationale, we carried out a computer-assisted cytochemical study of cytochrome oxidase (COX) activity on mitochondria of different size in the cerebellar cortex of adult rats. The total intra-mitochondrial area of the cytochemical precipitates (CPA)/mitochondrion, the area (MA) and the longer diameter (F(max)) of COX-positive organelles were measured. The ratio (R): CPA/MA was also calculated and referred to as the percentage of mitochondrial inner membrane area involved in COX activity. The regression analysis of R vs MA showed a significant inverse correlation (r=-0.905). The fourfold increase in MA from quartiles I to IV was matched by increases in F(max) and CPA, respectively, but it was also related to a 25% decrease in R. By matching quantitative cytochemical estimations of COX activity within mitochondria with the morphometric assessment of their ultrastructural features, the present study correlates size to the metabolic competence of COX-positive organelles. Quantitative cytochemistry of COX activity is currently regarded as a reliable marker of cellular metabolism; thus our findings support the hypothesis that enlargements in size are inversely correlated with the mitochondrial metabolic competence.