Phenolic Plant Extracts Induce Sirt1 Activity and Increase Antioxidant Levels in the Rabbit's Heart and Liver.

BACKGROUND: Several dietary phytochemicals potentially regulate the equilibrium between oxidant and antioxidant species. The aim of this study was to evaluate the effects of Lippia citriodora, Raphanus sativus, and Solanum lycopersicum on blood parameters, oxidative/antioxidant status, and SIRT1 activity in the rabbit's heart and liver. METHODS: Twenty rabbits were divided into 4 groups of 5 animals each. The control group (CN) received a feed without any additives. One intervention group received a supplement containing verbascoside (VB), another Raphanus sativus extract (RAP), and lastly lycopene (LYC). Oxidant-antioxidant parameters and SIRT1 activity were measured in plasma and in the heart and liver, respectively. RESULTS: The treatment with VB, RAP, and LYC resulted in a marked improvement in the blood lipid and glycaemic profile in respect to CN. VB was the most effective, but all three plant extracts induced a significant reduction in oxidant parameters as well as an increase in antioxidant tissue activity and vitamin A and E levels. SIRT1 activity was significantly increased in both VB and LYC compared to CN, but the increased levels in the VB group were far the highest. The multivariate analysis suggests that the benefits of VB, particularly the antiglycaemic and antioxidant effects, might be mediated by increasing SIRT1 activity.

Epigenetic nutraceutical diets in Alzheimer's disease.

There is growing support that environmental influences and individual genetic susceptibility may increase the incidence and accelerate the onset of Alzheimer's disease (AD). Epigenetic mechanisms encompass a complex regulatory network of modifications with considerable impact on health and disease risk. Abnormal epigenetic regulation is a hallmark in many pathological conditions including AD. It is well recognized that numerous bioactive dietary components mediate epigenetic modifications associated with the pathophysiology of several diseases. Although the influences of dietary factors on epigenetic regulation have been extensively investigated, only few studies have explored the effects of specific food components in regulating epigenetic patterns during neurodegeneration and AD. Epigenetic nutritional research has substantial potential for AD and may represent a window of opportunity to complement other interventions. Here, we provide a brief overview of the main mechanisms involved in AD, some of which may be epigenetically modulated by bioactive food.

Sex hormonal regulation and hormesis in aging and longevity: role of vitagenes.

Aging process is accompanied by hormonal changes characterized by an imbalance between catabolic hormones, such as cortisol and thyroid hormones which remain stable and hormones with anabolic effects (testosterone, insulin like growth factor-1 (IGF-1) and dehydroepiandrosterone sulphate (DHEAS), that decrease with age. Deficiencies in multiple anabolic hormones have been shown to predict health status and longevity in older persons.Unlike female menopause, which is accompanied by an abrupt and permanent cessation of ovarian function (both folliculogenesis and estradiol production), male aging does not result in either cessation of testosterone production nor infertility. Although the circulating serum testosterone concentration does decline with aging, in most men this decrease is small, resulting in levels that are generally within the normal range. Hormone therapy (HT) trials have caused both apprehension and confusion about the overall risks and benefits associated with HT treatment. Stress-response hormesis from a molecular genetic perspective corresponds to the induction by stressors of an adaptive, defensive response, particularly through alteration of gene expression. Increased longevity can be associated with greater resistance to a range of stressors. During aging, a gradual decline in potency of the heat shock response occur and this may prevent repair of protein damage. Conversely, thermal stress or pharmacological agents capable of inducing stress responses, by promoting increased expression of heat-shock proteins, confer protection against denaturation of proteins and restoration of proteome function. If induction of stress resistance increases life span and hormesis induces stress resistance, hormesis most likely result in increased life span. Hormesis describes an adaptive response to continuous cellular stresses, representing a phenomenon where exposure to a mild stressor confers resistance to subsequent, otherwise harmful, conditions of increased stress. This biphasic dose-response relationship, displaying low-dose stimulation and a high-dose inhibition, as adaptive response to detrimental lifestyle factors determines the extent of protection from progression to metabolic diseases such as diabetes and more in general to hormonal dysregulation and age-related pathologies. Integrated responses exist to detect and control diverse forms of stress. This is accomplished by a complex network of the so-called longevity assurance processes, which are composed of several genes termed vitagenes. Vitagenes encode for heat shock proteins (Hsps), thioredoxin and sirtuin protein systems. Nutritional antioxidants, have recently been demonstrated to be neuroprotective through the activation of hormetic pathways under control of Vitagene protein network. Here we focus on possible signaling mechanisms involved in the activation of vitagenes resulting in enhanced defense against functional defects leading to degeneration and cell death with consequent impact on longevity processes.

A new predictive equation for evaluating women body fat percentage and obesity-related cardiovascular disease risk.

BACKGROUND: Obesity represents a global public health problem due to its association with cardiovascular diseases and reduced lifespan. The most widely used classification of obesity is expressed as Body Mass Index (BMI); however, this formula is an imprecise adiposity measurement that ignores several important factors involved. Body Adiposity Index (BAI) was more recently proposed as an indirect evaluation of percentage body fat (PBF). PBF is a direct measure of person's relative body fat and a better predictor of obesity-related risk diseases than BMI and BAI. Since obesity and consequent diseases are considered epidemic, new accurate formulas for epidemiological studies are of interest to the scientific community. Because direct measurement of body composition could be quite expensive, the aims of our work were to analyse the distributions of PBF by Dual X-ray absorptiometry, and the creation of new predictive equation using only anthropometric measures that could be helpful to clinicians to assess easily body fat of female patients. METHODS/RESULTS: A sample of 1,031 Caucasian Italian women was recruited and BMI, BAI and PBF were evaluated. With the aim of developing a predictive model of PBF a multivariate regression model was fitted to observed data. CONCLUSIONS: The definition of universally recognized PBF by gender and age could have public health implications. In this study, we developed a new predictive PBF equation that does not require the use of medical instruments or skilled measurement techniques and that may be easily applicable to Italian women.

Immune-inflammatory responses and oxidative stress in Alzheimer's disease: therapeutic implications.

Alzheimer's disease (AD) is a heterogeneous and progressive neurodegenerative disease which in Western society mainly accounts for clinical dementia. AD has been linked to inflammation and oxidative stress. Neuro-pathological hallmarks are senile plaques, resulting from the accumulation of several proteins and an inflammatory reaction around deposits of amyloid, a fibrillar protein, Abeta, product of cleavage of a much larger protein, the beta-amyloid precursor protein (APP) and neurofibrillary tangles. Inflammation clearly occurs in pathologically vulnerable regions of AD and several inflammatory factors influencing AD development, i.e. environmental factors (pro-inflammatory phenotype) and/or genetic factors (pro-inflammatory genotype) have been described. Irrespective of the source and mechanisms that lead to the generation of reactive oxygen species, mammalian cells have developed highly regulated inducible defence systems, whose cytoprotective functions are essential in terms of cell survival. When appropriately activated, each one of these systems has the possibility to restore cellular homeostasis and rebalance redox equilibrium. Increasing evidence, support the notion that reduction of cellular expression and activity of antioxidant proteins and consequent augment of oxidative stress are fundamental causes for ageing processes and neurodegenerative diseases., including AD. The better understanding of different molecular and cellular inflammatory mechanisms is crucial for complete knowledge of AD pathophysiology, hence for its prevention and drug therapy. Accordingly, two lines of preventive therapeutics can be outlined, the first based on anti-inflammatory drugs, the second one on anti-oxidative properties.

Post-transcriptional regulation of HSP70 expression following oxidative stress in SH-SY5Y cells: the potential involvement of the RNA-binding protein HuR.

Brain aging is associated with a progressive imbalance between intracellular concentration of Reactive Oxygen Species (ROS) and cells ability to activate defensive genes. Heat Shock Protein 70 (HSP70) has been shown to act as a fundamental defensive mechanism for neurons exposed to an oxidant challenge, and its expression decreases during senescence. In the present report we show that the RNA-binding protein ELAV/HuR can affect, post-transcriptionally, the fate of HSP70 mRNA following H(2)O(2)-mediated oxidative stress in SH-SY5Y human neuroblastoma cells. As a consequence of H(2)O(2) treatment (1mM for 30 minutes), HSP70 mRNA accumulates in the ribosomes associated to the cytoskeleton, where parallel Western blotting experiments reveal statistically significant increase for both HuR and HSP70 protein levels. We also confirm the capability of HuR to bind to HSP70 mRNA, and describe how the biological effect of this ELAV protein on the HSP70 mRNA could be due to a direct phosphorylation in serine/threonine residues of HuR itself by the early (10 minutes) H(2)O(2)-mediated activation of PKC alpha. Our findings shed light on the post-transcriptional regulation of HSP70 expression, suggesting the existence of a new molecular cascade -involving PKC/HuR/HSP70- that possibly represents an early event in the cellular response to H(2)O(2)-mediated oxidative stress in SH-SY5Y human neuroblastoma cells. The present results lead us to speculate that an impairment in this regulatory mechanism might directly contribute to the defective cellular response to oxidative stress, thus helping to dissect a potential tool useful to counteract some aspects associated to cerebral senescence.

Redox modulation of heat shock protein expression by acetylcarnitine in aging brain: relationship to antioxidant status and mitochondrial function.

There is significant evidence to show that aging is characterized by a stochastic accumulation of molecular damage and by a progressive failure of maintenance and repair processes. Protective mechanisms exist in the brain which are controlled by vitagenes and include members of the heat shock system, heme oxygenase-I, and Hsp70 as critical determinants of brain stress tolerance. Given the broad cytoprotective properties of the heat shock response, molecules inducing this defense mechanism appear to be possible candidates for novel cytoprotective strategies. Acetyl-L-carnitine is proposed as a therapeutic agent for several neurodegenerative disorders, and the present study reports that treatment for 4 months of senescent rats with acetyl-L-carnitine induces heme oxygenase-1 as well as Hsp70 and SOD-2. This effect was associated with upregulation of GSH levels, prevention of age-related changes in mitochondrial respiratory chain complex expression, and decrease in protein carbonyls and HNE formation. We hypothesize that maintenance or recovery of the activity of vitagenes may delay the aging process and decrease the risk of age-related diseases. Particularly, modulation of endogenous cellular defense mechanisms via acetyl-L-carnitine may represent an innovative approach to therapeutic intervention in diseases causing tissue damage, such as neurodegeneration.

Heme oxygenase-1 transduction in endothelial cells causes downregulation of monocyte chemoattractant protein-1 and of genes involved in inflammation and growth.

Heme oxygenase (HO-1) has been implicated as an anti-inflammatory gene. HO-1 overexpression, transiently and chronically, affects heme protein expression, attenuates TNF-mediated cell death, and decreases adhesion molecules. We assessed the effect of oxidant-mediated agents such as glucose and heme on 8-epi-isoprostane PGF2alpha (8-epi-PGF2alpha) and monocyte chemoattractant protein-1 (MCP-1). Glucose and heme increased both 8-epi-PGF2alpha and MCP-1. Overexpression of HO-1 decreased both 8-epi-PGF2alpha and MCP-1. To identify target genes involved in HO-1-mediated regulation of inflammation, a serial analysis of gene expression mRNA profile was performed in endothelial cells (EC) overexpressing the human HO-1 gene by transduction of a retrovirus carrying the HO-1 gene. Gene arrays (differential displays among 2400 genes) were used to identify known and novel differentially expressed genes. The levels of expression for several genes were confirmed by real time PCR in cells overexpressing the HO-1 gene. In HO-1 overexpressing cells, VEGF and the prostaglandin transporter were greatly increased while MCP-1 levels were decreased by 2.5-fold. The data from this study are relevant to understanding the mechanisms underlying the pathophysiological effects of HO-1 deficiency on endothelial cell injury and inflammation.

Protective effect of carnosine during nitrosative stress in astroglial cell cultures.

Formation of nitric oxide by astrocytes has been suggested to contribute, via impairment of mitochondrial function, to the neurodegenerative process. Mitochondria under oxidative stress are thought to play a key role in various neurodegenerative disorders; therefore protection by antioxidants against oxidative stress to mitochondria may prove to be beneficial in delaying the onset or progression of these diseases. Carnosine has been recently proposed to act as antioxidant in vivo. In the present study, we demonstrate its neuroprotective effect in astrocytes exposed to LPS- and INFgamma-induced nitrosative stress. Carnosine protected against nitric oxide-induced impairment of mitochondrial function. This effect was associated with decreased formation of oxidatively modified proteins and with decreased up-regulation oxidative stress-responsive genes, such as Hsp32, Hsp70 and mt-SOD. Our results sustain the possibility that carnosine might have anti-ageing effects to brain cells under pathophysiological conditions leading to degenerative damage, such as aging and neurodegenerative disorders.

Increased expression of heat shock proteins in rat brain during aging: relationship with mitochondrial function and glutathione redox state.

It is generally recognized that lipid peroxides play an important role in the pathogenesis of several diseases and that sulfhydryl groups are critically involved in cellular defense against endogenous or exogenous oxidants. Recent evidence indicates that lipid peroxides directly participate in induction of cytoprotective proteins, such as heat shock proteins (Hsps), which play a central role in the cellular mechanisms of stress tolerance. Oxidative damage plays a crucial role in the brain aging process and induction of Hsps is critically utilized by brain cells in the repair process following various pathogenic insults. In the present study, we investigated, in rats 6, 12, and 28 months old, the role of heat shock expression on aging-induced changes in mitochondrial and antioxidant redox status. In the brain expression of Hsp72 and Hsc70 increased with age up to 28 months; at this age the maximum induction was observed in the hippocampus and substantia nigra followed by cerebellum, cortex, septum and striatum. Hsps induction was associated with significant changes in glutathione (GSH) redox state and HNE levels. Interestingly, a significant positive correlation between decrease in GSH and increase in Hsp72 was observed in all brain regions examined during aging. Analysis of mitochondrial complexes showed a progressive decrease of Complex I activity and mRNA expression in the hippocampus and a significant decrease of Complex I and IV activities in the substantia nigra and septum. Our results sustain a role for GSH redox state in Hsp expression. Increase of Hsp expression promotes the functional recovery of oxidatively damaged proteins and protects cells from progressive age-related cell damage. Conceivably, heat shock signal pathway by increasing cellular stress resistance may represent a crucial mechanism of defence against free radical-induced damage occurring in aging brain and in neurodegenerative disorders.

Relaxin potentiates the expression of inducible nitric oxide synthase by endothelial cells from human umbilical vein in in vitro culture.

The hormone relaxin (RLX), which can be detected in human venous cord blood, has been shown to be a potent vasodilator, acting through increased expression of inducible nitric oxide synthase (NOS II) and nitric oxide (NO) generation. This study aims at clarifying whether RLX, at concentrations of 100 and 1000 ng/ml for 6 or 12 h of exposure, can influence the expression of NOS isoforms in human umbilical vein endothelial cells (HUVEC) cultured in vitro. NOS mRNA expression was studied by quantitative real-time RT-PCR, NOS protein expression and activity was studied by Western blot and nitrite assay, and immunoreactive NOS localization was performed by confocal microscopy. Untreated HUVEC expressed all the NOS isoforms, especially the constitutive, endothelial-type NOS III and, to a lesser extent, NOS II and NOS I. RLX-treated cells showed an increased expression of NOS II, attaining a maximum with 1000 ng/ml RLX, which gave rise to increased NO generation, as shown by nitrite assay. This effect of RLX appears to be mediated by activation of NOS II transcription factor NF-kappaB, since it was abolished by the NF-kappaB inhibitors curcumin-95 and dexamethasone. These findings suggest that RLX in the umbilical vein might contribute to the NO-dependent regulation of vascular tone.

Redox regulation of heat shock protein expression in aging and neurodegenerative disorders associated with oxidative stress: a nutritional approach.

Oxidative stress has been implicated in mechanisms leading to neuronal cell injury in various pathological states of the brain. Alzheimer's disease (AD) is a progressive disorder with cognitive and memory decline, speech loss, personality changes and synapse loss. Many approaches have been undertaken to understand AD, but the heterogeneity of the etiologic factors makes it difficult to define the clinically most important factor determining the onset and progression of the disease. However, increasing evidence indicates that factors such as oxidative stress and disturbed protein metabolism and their interaction in a vicious cycle are central to AD pathogenesis. Brains of AD patients undergo many changes, such as disruption of protein synthesis and degradation, classically associated with the heat shock response, which is one form of stress response. Heat shock proteins are proteins serving as molecular chaperones involved in the protection of cells from various forms of stress.Recently, the involvement of the heme oxygenase (HO) pathway in anti-degenerative mechanisms operating in AD has received considerable attention, as it has been demonstrated that the expression of HO is closely related to that of amyloid precursor protein (APP). HO induction occurs together with the induction of other HSPs during various physiopathological conditions. The vasoactive molecule carbon monoxide and the potent antioxidant bilirubin, products of HO-catalyzed reaction, represent a protective system potentially active against brain oxidative injury. Given the broad cytoprotective properties of the heat shock response there is now strong interest in discovering and developing pharmacological agents capable of inducing the heat shock response. Increasing interest has been focused on identifying dietary compounds that can inhibit, retard or reverse the multi-stage pathophysiological events underlying AD pathology. Alzheimer's disease, in fact, involves a chronic inflammatory response associated with both brain injury and beta-amyloid associated pathology. All of the above evidence suggests that stimulation of various repair pathways by mild stress has significant effects on delaying the onset of various age-associated alterations in cells, tissues and organisms. Spice and herbs contain phenolic substances with potent antioxidative and chemopreventive properties, and it is generally assumed that the phenol moiety is responsible for the antioxidant activity. In particular, curcumin, a powerful antioxidant derived from the curry spice turmeric, has emerged as a strong inducer of the heat shock response. In light of this finding, curcumin supplementation has been recently considered as an alternative, nutritional approach to reduce oxidative damage and amyloid pathology associated with AD. Here we review the importance of the heme oxygenase pathway in brain stress tolerance and its significance as an antidegenerative mechanism potentially important in AD pathogenesis. These findings have offered new perspectives in medicine and pharmacology, as molecules inducing this defense mechanism appear to be possible candidates for novel cytoprotective strategies. In particular, manipulation of endogenous cellular defense mechanisms such as the heat shock response, through nutritional antioxidants or pharmacological compounds, represents an innovative approach to therapeutic intervention in diseases causing tissue damage, such as neurodegeneration. Consistent with this notion, maintenance or recovery of the activity of vitagenes, such as the HO gene, conceivably may delay the aging process and decrease the occurrence of age-related neurodegenerative diseases.

Human heme oxygenase: cell cycle-dependent expression and DNA microarray identification of multiple gene responses after transduction of endothelial cells.

The purpose of the present study was to examine the role of human heme oxygenase (human HO-1) in cell cycle progression following exposure to heme or human HO-1 gene transfer and to identify target genes associated with human HO-1-meditated increases in cell cycle progression using cDNA microarray technology. Heme-induced robust human HO-1 expression in quiescent human microvessel endothelial cells cultured in 1% FBS and the levels of human HO-1 expression progressively declined without a change in the cell cyclin. To identify genes regulated by human HO-1 in the cell cycle, human endothelial cells were transduced with a retroviral vector encoded with human HO-1 gene or an empty vector. Transgene expression and functionality of the recombinant protein were assessed by Western blotting, enzyme activity, carbon monoxide, cGMP production, and cell cycle analysis. Human cDNA gene array and quantitative real-time RT-PCR were used to identify both known and novel differentially expressed genes in cells overexpressing human HO-1. Major findings were upregulation of several genes associated with cell cycle progression, including cyclin E and D; downregulation of cyclin-dependent kinase inhibitors p21 and p27, cyclin-dependent kinases 2, 5, and 6, and monocyte chemoattractant protein-1; and upregulation of growth factors, including vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor I (VEGFRI), endothelial growth factor (EGF) and hepatic-derived growth factor (HDGF). These findings identify an array of gene responses to overexpression of human HO-1 and elucidate new aspects of human HO-1 signaling involved in cell growth.

Disruption of thiol homeostasis and nitrosative stress in the cerebrospinal fluid of patients with active multiple sclerosis: evidence for a protective role of acetylcarnitine.

Recent studies suggest that NO and its reactive derivative peroxynitrite are implicated in the pathogenesis of multiple sclerosis (MS). Patients dying with MS demonstrate increased astrocytic inducible nitric oxide synthase activity, as well as increased levels of iNOS mRNA. Peroxynitrite is a strong oxidant capable of damaging target tissues, particularly the brain, which is known to be endowed with poor antioxidant buffering capacity. Inducible nitric oxide synthase is upregulated in the central nervous system (CNS) of animals with experimental allergic encephalomyelitis (EAE) and in patients with MS. We have recently demonstrated in patients with active MS a significant increase of NOS activity associated with increased nitration of proteins in the cerebrospinal fluid (CSF). Acetylcarnitine is proposed as a therapeutic agent for several neurodegenerative disorders. Accordingly, in the present study, MS patients were treated for 6 months with acetylcarnitine and compared with untreated MS subjects or with patients noninflammatory neurological conditions, taken as controls. Western blot analysis showed in MS patients increased nitrosative stress associated with a significant decrease of reduced glutathione (GSH). Increased levels of oxidized glutathione (GSSG) and nitrosothiols were also observed. Interestingly, treatment of MS patients with acetylcarnitine resulted in decreased CSF levels of NO reactive metabolites and protein nitration, as well as increased content of GSH and GSH/GSSG ratio. Our data sustain the hypothesis that nitrosative stress is a major consequence of NO produced in MS-affected CNS and implicate a possible important role for acetylcarnitine in protecting brain against nitrosative stress, which may underlie the pathogenesis of MS.

Heme oxygenase-1 expression levels are cell cycle dependent.

Heme oxygenase-1 (HO-1) is a stress protein, which has been suggested to participate in defense mechanisms against agents that may induce oxidative injury, such as angiotensin II (Ang II). The purpose of the present study was to examine the role of human HO-1 in cell-cycle progression. We investigated the effect of Ang II on HO-1 gene expression in serum-deprived media to drive human endothelial cells into G(0)/G(1) (1% FBS) compared to exponentially grown cells (10% FBS). The addition of Ang II (100 ng/ml) to endothelial cells increased HO-1 protein and activity in G(0)/G(1) in a time-dependent manner, reaching a maximum HO-1 level at 16 h. Real-time RT-PCR demonstrated that Ang II increased the levels of HO-1 mRNA in G(0)/G(1) as early as 1 h. The rate of HO-1 induction in response to Ang II was several-fold higher in serum-starved cells compared to cells cultured in continuous 10% FBS. The addition of Ang II increased the generation of 8-epi-isoprostane PGF(2 alpha). Inhibition of HO-1, by Stannis mesoporphyrin (SnMP), potentiated Ang II-mediated DNA damage and generation of 8-epi-isoprostane PGF(2 alpha). These results imply that expression of HO-1 in G(0)/G(1), in the presence of Ang II, may be a key player in attenuating DNA damage during cell-cycle progression. Thus, exposure of endothelial cells to Ang II causes a complex response involving generation of superoxide anion, which may be involved in DNA damage. Upregulation of HO-1 ensures the generation of bilirubin and carbon monoxide (CO) in G(0)/G(1) phase to counteract Ang II-mediated oxidative DNA damage. Inducibility of HO-1 in G(0)/G(1) phase is essential and probably regulated by a complex system involving oxygen species to assure controlled cell growth.

Molecular chaperones and their roles in neural cell differentiation.

During the development of the nervous system, a large number of neurons are eliminated through naturally occurring neuronal death. Many morphological and biochemical properties of such dying neurons are reminiscent not only of apoptosis, a type of death involving the action of genetically programmed events, but also of epigenetic phenomena such as oxidative stress. Increasing evidence demonstrates that oxidative stress alters the expression of antioxidant enzymes and enhances expression and/or DNA binding of numerous transcription factors, including heat shock factor. The latter is a transcription factor for specific promoter elements located upstream of the heat shock genes. Heat shock proteins (Hsps) are essential, highly conserved proteins that are needed for normal cell growth and maintenance, and expression of Hsps has been detected during embryogenesis in various organisms. Developmental profiles of Hsps indicate that they are differentially regulated during neural maturation, suggesting a role for Hsps in neural cell differentiation. Their putative function in cell remodeling during migration and differentiation, as well as during postnatal development, a time of extensive cell differentiation, is considered in the present review. Moreover, the function of Hsps in cell signaling, protein transport and the effect of heat shock on neural plate induction and brain development are discussed.

Regional distribution of heme oxygenase, HSP70, and glutathione in brain: relevance for endogenous oxidant/antioxidant balance and stress tolerance.

It is generally recognized that lipid peroxides play an important role in the pathogenesis of several diseases and that sulfhydryl groups are critically involved in cellular defense against endogenous or exogenous oxidants. Recent evidence indicates that lipid peroxides directly participate in induction of cytoprotective proteins, such as heat shock proteins (Hsps), which play a central role in the cellular mechanisms of stress tolerance. Heme oxygenase (HO) is a stress protein that has been implicated in defense mechanisms against agents that may induce oxidative injury, such as endotoxins, cytokines and heme and its induction represents a common feature in a number of neurodegenerative diseases. In the present report we studied regional distribution of heme oxygenase (HO) activity and protein expression, together with that of Hps70, in brain of C57BL6 mice. Endogenous lipid peroxidation was investigated on the basis of the analysis of ultra weak chemiluminescence, hydro peroxides and lipid soluble fluorescent products, and compared to the regional distribution of thiols, antioxidant enzymes and trace metals. Our results show that levels of HO activity and expression of inducible Hsp70 and the ratio of GSH/GSSG in the different brain regions examined were positively correlated with the content of peroxides. Substantia Nigra was the brain area exhibiting the highest levels of HO-2, constitutive and inducible Hsp70, GSSG, peroxides, iron, and calcium, in contrast with the lowest content in GSH, GSH/GSSG ratio and glutathione reductase activity, compared to the other cerebral regions examined. Among these, cortex showed the lowest levels of HO-2, Hsp70, GSSG and peroxides that were associated with the highest levels of GSH and GSH/GSSG ratio. These data support the hypothesis that the glutathione redox state and basal peroxides can directly participate in the signaling pathways of heat shock protein expression and hence of stress tolerance.

Caffeic acid phenethyl ester and curcumin: a novel class of heme oxygenase-1 inducers.

Heme oxygenase-1 (HO-1) is a redox-sensitive inducible protein that provides efficient cytoprotection against oxidative stress. Curcumin, a polyphenolic natural compound that possesses anti-tumor and anti-inflammatory properties, has been reported recently to induce potently HO-1 expression in vascular endothelial cells (Free Rad Biol Med 28:1303-1312, 2000). Here, we extend our previous findings by showing that caffeic acid phenethyl ester (CAPE), another plant-derived phenolic agent, markedly increases heme oxygenase activity and HO-1 protein in astrocytes. The effect seems to be related to the peculiar chemical structures of curcumin and CAPE, because analogous antioxidants containing only portions of these two molecules were totally ineffective. At a final concentration of 30 microM, both curcumin and CAPE maximally up-regulated heme oxygenase activity while promoting marked cytotoxicity at higher concentrations (50-100 microM). Similar results were obtained with Curcumin-95, a mixture of curcuminoids commonly used as a dietary supplement. Incubation of astrocytes with curcumin or CAPE at concentrations that promoted maximal heme oxygenase activity resulted in an early increase in reduced glutathione followed by a significant elevation in oxidized glutathione contents. A curcumin-mediated increase in heme oxygenase activity was not affected by the glutathione precursor and thiol donor N-acetyl-L-cysteine. These data suggest that regulation of HO-1 expression by polyphenolic compounds is evoked by a distinctive mechanism which is not necessarily linked to changes in glutathione but might depend on redox signals sustained by specific and targeted sulfydryl groups. This study identifies a novel class of natural substances that could be used for therapeutic purposes as potent inducers of HO-1 in the protection of tissues against inflammatory and neurodegenerative conditions.

Long-term ethanol administration enhances age-dependent modulation of redox state in brain and peripheral organs of rat: protection by acetyl carnitine.

Evidence is accumulating that intermediates of oxygen reduction may be associated with the development of alcoholic disease. Free radical-induced perturbation of the oxidant/antioxidant balance in the cell is widely recognized as the main causative factor of age-related disorders. In the present study we investigated the effects of 20 months of ethanol consumption on the antioxidant defense system in different rat organs compared with normal aging in the absence and presence of treatment with L-acetyl carnitine. We demonstrate that aged rats underwent significant perturbation of the antioxidant defense system, as indicated by depletion of reduced glutathione (GSH) content, increased oxidized GSH, free radical-induced luminescence associated with increased hydroxynonenal content and decreased GSH reductase activity. These modifications, observed particularly in brain and liver compared with other organs, were enhanced by long-term alcohol exposure and, interestingly, were significantly reduced with acetyl carnitine supplements. Our results indicate that decreased GSH reductase activity and thiol depletion are important factors in effecting a pathogenic role for oxidative stress in aging and in all situations in which age-correlated and oxidant-induced changes occur, such as in alcoholism. Administration of acetyl carnitine greatly reduces these metabolic abnormalities. Our findings support its pharmacological potential in the management of alcoholic disturbances.

Long-term ethanol administration enhances age-dependent modulation of redox state in different brain regions in the rat: protection by acetyl carnitine.

Chronic alcoholism is a major public health problem and causes multiorgan diseases and toxicity. Although the majority of ethanol ingested is metabolized by the liver, it has intoxicating effects in the brain. Evidence is accumulating that intermediates of oxygen reduction may be associated with the development of alcoholic disease. Several studies have shown the capacity of carnitine and its derivatives to influence ethanol metabolism. We have previously demonstrated that preadministration of L-carnitine to rats receiving ethanol significantly reduced fatty acid ethyl esters in different organs and that the carnitine/acylcarnitine system is crucial for maintaining a functional acetyl-CoA/CoA ratio under conditions in which cellular homeostasis is exposed to the deleterious effects of accumulating organic acids. Ethanol, administered to rats for 20 months, induced significant changes in the status of glutathione, primarily in the brain regions of hippocampus and cerebellum, followed by cortex and striatum, where a decrease in reduced glutathione (GSH) and the GSH/oxidized glutathione ratio was found. The same brain regions showed a significant increase in free radical-induced luminescence and hydroxynonenal (HNE), which were associated with decreased GSH reductase activity. Long-term supplementation with acetyl carnitine significantly reduced GSH depletion, particularly in the brain regions of hippocampus, an effect associated with decreased luminescence and HNE formation. In addition, acetyl carnitine treatment increased GSH reductase and arginase activities. Our results indicate that decreased GSH reductase activities associated with thiol depletion are important factors sustaining a pathogenic role in alcohol-related pathologies. Administration of acetyl carnitine greatly reduces these metabolic abnormalities. This evidence supports the pharmacological potential of acetyl carnitine in the management of alcoholic disturbances.