Oxidative damage to mitochondrial DNA and glutathione oxidation in apoptosis: studiesin vivoandin vitro

Free radicals may be involved in apoptosis although this is the subject of some controversy. Furthermore, the source of free radicals in apoptotic cells is not certain. The aim of this study was to elucidate the role of oxidative stress in the induction of apoptosis in serum-deprived fibroblast cultures and in weaned lactating mammary glands as in vitro and in vivo experimental models, respectively. Oxidative damage to mtDNA is higher in apoptotic cells than in controls. Oxidized glutathione (GSSG) levels in mitochondria from lactating mammary gland are also higher in apoptosis. There is a direct relationship between mtDNA damage and the GSSG/reduced glutathione (GSH) ratio. Furthermore, wh…

Role of RCAN1 in stress induced cell adaptation

Hepatic amino acid uptake is decreased in lactating rats. In vivo and in vitro studies.

To study the redistribution of amino acids to the mammary gland during lactation we used lactating and virgin rats fed liquid diets. Virgin rats were divided in two groups: one group was fed daily a diet containing the same amount of protein that was consumed the previous day by lactating rats (high protein diet-fed rats), and the other virgin group was fed the normal liquid diet (control). The hepatic availability of amino acids was significantly higher in the lactating rats than in the other two groups, but the uptake and fractional extraction of amino acids by the liver were lower in lactating rats than in the high protein-fed virgin controls. When primary hepatocyte cultures were used, …

Higher oxidative stress in human dental pulp stem cells cultured at 21% O2 compared to 5% O2

Effect of oral glutathione on hepatic glutathione levels in rats and mice

Administration of oral glutathione (GSH) increases hepatic GSH levels in fasted rats, in mice treated with GSH depletors such as diethyl maleate and in mice treated with high doses of paracetamol. An increase in hepatic GSH levels after administration of oral GSH does not occur in animals treated with buthionine sulphoximine, an inhibitor of GSH synthesis. Administration of oral GSH leads to an increase in the concentration of l-cysteine, a precursor of GSH, in portal blood plasma. Oral administration of l-methionine produced a significant decrease of hepatic ATP in fasted rats, but not in fed rats. Administration ofN−acetylcysteine or GSH did not affect the hepatic ATP levels. The results …

Vitamin E activates CRABP-II gene expression in cultured human fibroblasts, role of protein kinase C

The treatment of human fibroblasts with different tocopherols in the presence of retinol caused an increase in cytoplasmic retinoic acid binding protein II (CRABP-II) mRNA and protein. The possibility of an involvement of protein kinase C (PKC) in the response to tocopherols was supported by the results obtained with the PKC-specific inhibitors, calphostin C and bisindolylmaleimide I. The effect of alpha-tocopherol was prevented by okadaic acid, suggesting that a protein phosphatase is responsible for PKC dephosphorylation produced by the presence of tocopherols. The results shown support the hypothesis that phosphorylation/dephosphorylation of RXRalpha via PKC may be involved in the regula…

Role of Vitamin A in Mammary Gland Development and Lactation

Vitamin A (all-trans-retinol), its active derivatives retinal and retinoic acid, and their synthetic analogues constitute the group of retinoids. It is obtained from diet either as preformed vitamin A or as carotenoids. Retinal plays a biological role in vision, but most of the effects of vitamin A are exerted by retinoic acid, which binds to nuclear receptors and regulates gene transcription. Vitamin A deficiency is an important nutritional problem, particularly in the developing world. Retinol and carotenoids from diet during pregnancy and lactation influence their concentration in breast milk, which is important in the long term, not only for the offspring, but also for maternal health. …

Centenarians overexpress BCL-xL, which confers them a protection against apoptosis, oxidative stress and immunosenescence

Centenarians not only have an extraordinary longevity, but also show a compression of morbidity. They preserve the capacity of maintaining homeostasis, and this is the reason for them to reach such a long life. We studied their mRNA expression profile and identified 1721 mRNAs differentially expressed by centenarians when compared with septuagenarians and young people. A sub-network analysis showed six common genes: interferon, T-cell receptor, tumor necrosis factor, SP1 transcription factor, transforming growth factor and IL-32.These six centenarian-specific genes are related to Bcl-xL, Fas, and Fas ligand all of them involved in the control of apoptosis. RT-PCR analysis confirmed that cen…

Amino acid transport across each side of the blood-brain barrier.

Blood sulfur-amino acid concentration reflects an impairment of liver transsulfuration pathway in patients with acute abdominal inflammatory processes

Whole-blood free amino acids were measured in a control group made up of eight healthy women fasted for 12 h and also in eight patients with acute pancreatitis, five patients with acute cholecystitis and seven patients with acute appendicitis. Blood was withdrawn immediately on admission to hospital and again 3 d later following a controlled peripheral parenteral nutrition diet; this is with the exception of the appendicitis group. L-CYSTATHIONINE AND l-methionine concentrations were significantly higher in pancreatitis and appendicitis patients when compared with controls. In the pancreatitis and cholecystitis patients, l-serine concentration was also significantly higher when compared wit…

Evaluation of the quality of publications on randomized clinical trials using the Consolidated Standards of Reporting Trials (CONSORT) statement guidelines in a Spanish tertiary hospital.

The main reason for conducting a clinical trial (CT) is to test the effect of a drug or medical procedure to improve treatment of a disease. CTs contribute most when they are rigorously conducted and the results are published adequately. The aim of this study is to assess, using the CONSORT statement guidelines, the quality of reporting of completed CTs conducted at a tertiary hospital to determine which sections of the articles should be improved. CTs published between 2002 and 2008 were identified by searching the MEDLINE and Cochrane Library. Forty of 127 completed CTs were published. There was a marked increase in the number of articles and the quality of the journals that published the…

How Glutamate Is Managed by the Blood-Brain Barrier

A facilitative transport system exists on the blood brain barrier (BBB) that has been tacitly assumed to be a path for glutamate entry to brain. But glutamate is a non-essential amino acid whose brain content is much greater than plasma, and studies in vivo show that glutamate does not enter brain in material quantities except in those small regions with fenestrated capillaries (circumventricular organs). The situation became understandable when luminal (blood facing) and abluminal (brain facing) membranes were isolated and studied separately. Facilitative transport of glutamate and glutamine exist only on the luminal membranes whereas Na+-dependent transport systems for glutamate, glutamin…

In vivo studies of altered expression patterns of p53 and proliferative control genes in chronic vitamin A deficiency and hypervitaminosis

Several clinical trials have revealed that individuals who were given beta-carotene and vitamin A did not have a reduced risk of cancer compared to those given placebo; rather, vitamin A could actually have caused an adverse effect in the lungs of smokers [Omenn, G.S., Goodman, G.E., Thornquist, M.D., Balmes, J., Cullen, M.R., Glass, A., Keogh, J.P., Meyskens, F.L., Valanis, B., Williams, J.H., Barnhart, S. & Hammar, S. N. Engl. J. Med (1996) 334, 1150-1155; Hennekens, C.H., Buring, J.E., Manson, J.E., Stampfer, M., Rosner, B., Cook, N.R., Belanger, C., LaMotte, F., Gaziano, J.M., Ridker, P.M., Willet, W. & Peto, R. (1996) N. Engl. J. Med. 334, 1145-1149]. Using differential display techniq…

Nitric oxide triggers mammary gland involution after weaning: remodelling is delayed but not impaired in mice lacking inducible nitric oxide synthase

During mammary gland involution, different signals are required for apoptosis and tissue remodelling. To explore the role of NO in the involution of mammary tissue after lactation, NOS2 (inducible nitric oxide synthase)-KO (knockout) mice were used. No apparent differences were observed between NOS2-KO and WT (wild-type) animals during pregnancy and lactation. However, upon cessation of lactation, a notable delay in involution was observed, compared with WT mice. NOS2-KO mice showed increased phosphorylation of STAT (signal transducer and activator of transcription) 5 during weaning, concomitant with increased beta-casein mRNA levels when compared with weaned WT glands, both hallmarks of th…

Targeting Alzheimer’s disease with multimodal polypeptide-based nanoconjugates

LRP1-targeted St-Cl–polyglutamate conjugates as multivalent neuroprotective/neurotrophic therapeutics for Alzheimer’s disease.

Aβ and tau toxicities in Alzheimer’s are linked via oxidative stress-induced p38 activation: Protective role of vitamin E

AbstractOxidative stress is a hallmark of Alzheimer’s disease (AD). We propose that rather than causing damage because of the action of free radicals, oxidative stress deranges signaling pathways leading to tau hyperphosphorylation, a hallmark of the disease. Indeed, incubation of neurons in culture with 5 µM beta-amyloid peptide (Aβ) causes an activation of p38 MAPK (p38) that leads to tau hyperphosphorylation. Inhibition of p38 prevents Aβ-induced tau phosphorylation. Aβ-induced effects are prevented when neurons are co-incubated with trolox (the water-soluble analog of vitamin E).We have confirmed these results in vivo, in APP/PS1 double transgenic mice of AD. We have found that APP/PS1 …

Oral glutathione increases hepatic glutathione and prevents acetaminophen toxicity

Administration of oral glutathione (GSH) increases hepatic GSH levels in fasted rats, in mice treated with GSH depletors such as diethylmaleate and in mice treated with high doses of paracetamol. An increase in hepatic GSH levels after administration of oral GSH does not occur in animals treated with buthionine suphoximine, an inhibitor of GSH synthesis. Administration of oral GSH leads to an increase in the concentration of L-cysteine, a precursor of GSH, in portal blood plasma. Oral administration of L-methio-nine to fasted rats produced a significant decrease of hepatic ATP, but not in fed rats. Administration of N-acetyl-cysteine or GSH did not affect the hepatic ATP levels. The results…

The Complementary Membranes Forming the Blood-Brain Barrier

Brain capillary endothelial cells form the blood-brain barrier. They are connected by extensive tight junctions, and are polarized into luminal (blood-facing) and abluminal (brain-facing) plasma membrane domains. The polar distribution of transport proteins allows for active regulation of brain extracellular fluid. Experiments on isolated membrane vesicles from capillary endothelial cells of bovine brain demonstrated the polar arrangement of amino acid and glucose transporters, and the utility of such arrangements have been proposed. For instance, passive carriers for glutamine and glutamate have been found only in the luminal membrane of blood-brain barrier cells, while Na-dependent second…

In vivo GSH depletion induces c-myc expression by modulation of chromatin protein complexes.

Abstract We hypothesize that glutathione (GSH) fluctuations could have a prominent role in the modulation of c-myc expression through a mechanism affecting chromatin remodeling complexes. This could lead to an open chromatin structure accessible to transcription factors. We studied the in vivo effect of GSH depletion on these complexes bound to the c-myc promoter in the liver of l-buthionine-(S,R)-sulfoximine (BSO)-treated rats. Using chromatin immunoprecipitation we found that 3 h after BSO treatment the repressing complexes Id2 and Sin3A (part of a histone–deacetylase complex) were released from the c-myc promoter. STAT3 was phosphorylated and associated with its coactivator p300 with int…

Vitamin A deficiency causes oxidative damage to liver mitochondria in rats.

Mitochondrial damage in rat liver induced by chronic vitamin A-deficiency was studied using three different groups of rats: (i) control rats, (ii) rats fed a vitamin A-free diet until 50 d after birth and (iii) vitamin A-deficient rats re-fed a control diet for 30 d. No statistical difference in body weight and food intake was found between control and vitamin A-deficient rats. Liver GSH concentration was similar in both groups. However, in vitamin A-deficient rats, the mitochondrial GSH/GSSG ratio was significantly lower and the levels of malondialdehyde (MDA) and 8-oxo-7, 8-dihydro-2'-deoxyguanosine (oxo8dG) were higher when compared to control rats. These values were partially restored i…

Mitochondrial oxidative stress and CD95 ligand: A dual mechanism for hepatocyte apoptosis in chronic alcoholism

Apoptosis plays an important role in the progression of alcohol-induced liver disease to cirrhosis. Oxidative stress is an early event in the development of apoptosis. The major aim of this study was to study the conditions in which oxidative stress occurs in chronic alcoholism and its relationship with apoptosis of hepatocytes. We have found that oxidative stress is associated with chronic ethanol consumption in humans and in rats, in the former independently of the existence of alcohol-induced liver disease. Ethanol or acetaldehyde induces apoptosis in hepatocytes isolated from alcoholic rats, but not in those from control rats. Inhibition of aldehyde dehydrogenase, but not of cytochrome …

La sobreexpresión de Fas en moscas aumenta su supervivencia

Pyroglutamate stimulates Na+ -dependent glutamate transport across the blood-brain barrier.

Regulation of Na(+)-dependent glutamate transport was studied in isolated luminal and abluminal plasma membranes derived from the bovine blood-brain barrier. Abluminal membranes have Na(+)-dependent glutamate transporters while luminal membranes have facilitative transporters. This organization allows glutamate to be actively removed from brain. gamma-Glutamyl transpeptidase, the first enzyme of the gamma-glutamyl cycle (GGC), is on the luminal membrane. Pyroglutamate (oxoproline), an intracellular product of GGC, stimulated Na(+)-dependent transport of glutamate by 46%, whereas facilitative glutamate uptake in luminal membranes was inhibited. This relationship between GGC and glutamate tra…

El resveratrol induce catabolismo lipídico en ratones C57Bl/6

Vitamin E deficiency induces liver nuclear factor-κB DNA-binding activity and changes in related genes

The biological functions of vitamin E have been classically attributed to its property as a potent inhibitor of lipid peroxidation in cellular membranes. However, in 1991, Azzi's group first described that alpha-tocopherol inhibits smooth muscle cell proliferation in a protein kinase C (PKC)-dependent way, demonstrating a non-antioxidant cell signalling function for vitamin E. More recently, the capacity of alpha-tocopherol to modulate gene expression with the implication of different transcription factors, beyond its antioxidant properties, has also been established. This study was to determine the effect of vitamin E-deficiency on liver nuclear factor-kappa B (NF-kappaB) DNA-binding activ…

Chronic ethanol feeding causes oxidative stress in rat liver mitochondria. Prevention by S-adenosyl methionine

Inhibition of γ-glutamyl transpeptidase decreases amino acid uptake in human keratinocytes in culture

Abstract Acivicin inhibits γ-glutamyl transpeptidase activity in human keratinocytes in culture. Treatment of these cells with acivicin produces a decrease in the uptake of L-[U-14C]alanine, 2-amino-[1-14C]-isobutyrate, L[U-14C]leucine and l-aminocyclopentane-l-[14C]carboxylate. D-[U-14C]glucose uptake is not affected by the presence of acivicin. These results support, for the first time in vitro, the hypothesis that the γ-glutarml cycle may be involved in amino acid uptake by human cells.

Increased plasma xanthine oxidase activity is related to nuclear factor kappa beta activation and inflammatory markers in familial combined hyperlipidemia

Abstract Background and aims Xanthine oxidase (XO) has been described as one of the major enzymes producing free radicals in blood. Oxidative stress and inflammatory processes have been implicated in the pathogenesis of endothelial dysfunction and the progression of atherosclerosis but until now, there is little data about the influence of vascular prooxidant systems and inflammation in familial combined hyperlipidemia (FCH). Our goal was to evaluate whether XO activity was altered in FCH and if it was related to the inflammatory process represented by NFkB, IL-6 and hsCRP, and assessing the correlation between XO activity and insulin resistance (IR). Method and results 40 Non-related subje…

Los descendientes de centenarios como modelo de envejecimiento saludable

How Glutamate Is Managed by the Blood-Brain Barrier.

A facilitative transport system exists on the blood–brain barrier (BBB) that has been tacitly assumed to be a path for glutamate entry to the brain. However, glutamate is a non-essential amino acid whose brain content is much greater than plasma, and studies in vivo show that glutamate does not enter the brain in appreciable quantities except in those small regions with fenestrated capillaries (circumventricular organs). The situation became understandable when luminal (blood facing) and abluminal (brain facing) membranes were isolated and studied separately. Facilitative transport of glutamate and glutamine exists only on the luminal membranes, whereas Na+-dependent transport systems for g…

Inhibition of liver trans-sulphuration pathway by propargylglycine mimics gene expression changes found in the mammary gland of weaned lactating rats: role of glutathione

In the lactatingmammary gland, weaning produces mitochondrial cytochrome c release and nuclear DNA fragmentation, as determined by gel electrophoresis. This is followed by a significant decrease in lactation. Weaning for 2 h produces an early induction of the tumour suppressor/transcription factor p53, whereas the oncoprotein c-Jun and c-Jun N-terminal kinase are elevated after 24 h of weaning when compared with controls. The expression of p21cip1 and p27kip1, cyclin-dependent kinase inhibitors, was significantly higher in weaned rats when compared with control lactating rats. All the changes mentioned above also happen in the lactatingmammary gland when propargylglycine, an inhibitor of th…

Differential functions of calpain 1 during epithelial cell death and adipocyte differentiation in mammary gland involution

Calpains become activated in the mammary gland early during weaning, cleaving several proteins located mainly in the cell membrane, but also in other organelles such as lysosomes, mitochondria and nuclei. By immunofluorescence and Western blot analysis, we have demonstrated the nuclear translocation of calpain-1 and calpain-2, together with the cleavage of several cytoplasmic nucleoporins in epithelial cells of the lobulo-alveolar compartment. In vivo and in vitro calpain inhibition prevented this nucleoporin degradation. In addition, calpain-1 was also present in the nucleus of non-epithelial mammary tissue cells, concomitant with adipocyte re-differentiation. Calpain-1 was internalized wi…

Special issue: Exercise redox biology from health to performance

Na+ -dependent neutral amino acid transporters A, ASC, and N of the blood-brain barrier: mechanisms for neutral amino acid removal.

Four Na+-dependent transporters of neutral amino acids (NAA) are known to exist in the abluminal membranes (brain side) of the blood-brain barrier (BBB). This article describes the kinetic characteristics of systems A, ASC, and N that, together with the recently described Na+-dependent system for large NAA (Na+-LNAA), provide a basis for understanding the functional organization of the BBB. The data demonstrate that system A is voltage dependent (3 positive charges accompany each molecule of substrate). Systems ASC and N are not voltage dependent. Each NAA is a putative substrate for at least one system, and several NAA are transported by as many as three. System A transports Pro, Ala, His,…

Validación de la carbonilación proteica como biomarcador de fragilidad

Role of cytokines and oxidative stress in the pathophysiology of acute pancreatitis: therapeutical implications.

Abstract Severe acute pancreatitis causes a high incidence of mortality due to the systemic inflammatory response syndrome leading to multiple organ failure. At present, there is no treatment against severe acute pancreatitis, other than supportive critical care. The relationship between pancreatic injury and the uncontrolled systemic response is not completely understood. Nevertheless, experimental and clinical evidences have shown that pro-inflammatory cytokines and oxidative stress are critically involved in the development of local and systemic complications associated with severe acute pancreatitis. Serum levels of pro-inflammatory cytokines, such as TNF-alpha and IL-1beta, increase du…

The L-glutamate transporters GLAST (EAAT1) and GLT-1 (EAAT2): expression and regulation in rat lactating mammary gland.

The Na(+)-dependent L-glutamate transporters GLAST (EAAT1) and GLT-1 (EAAT2), were expressed in rat lactating mammary gland, but EAAC1 (EAAT3) was not. GLT-1 expression in rat lactating mammary gland was constant in all the physiological situations studied; however, the GLAST expression is under tight regulation. Fasting for 24 h decreased the GLAST expression which returned to control values after refeeding. Weaning for 24 h produced a decrease in GLAST expression through a mechanism independent of prolactin deficiency. Resuckling for 6 h returned the expression of this transporter to control values. There is a correlation between the levels of GLAST (mRNA and protein) and the in vivo upta…

Glutathione regulates telomerase activity in 3T3 fibroblasts.

Changes in telomerase activity have been associated either with cancer, when activity is increased, or with cell cycle arrest when it is decreased. We report that glutathione, a physiological antioxidant present at high intracellular concentrations, regulates telomerase activity in cells in culture. Telomerase activity increases in 3T3 fibroblasts before exponential cell growth. The peak of telomerase activity takes place 24 h after plating and coincides with the maximum levels of glutathione in the cells. When cells are treated with buthionine sulfoximine, which decreases glutathione levels in cells, telomerase activity decreases by 60%, and cell growth is delayed. Glutathione depletion in…

Nitration of cathepsin D enhances its proteolytic activity during mammary gland remodelling after lactation

Proteomic studies in the mammary gland of control lactating and weaned rats have shown that there is an increased pattern of nitrated proteins during weaning when compared with controls. Here we report the novel finding that cathepsin D is nitrated during weaning. The expression and protein levels of this enzyme are increased after 8 h of litter removal and this up-regulation declines 5 days after weaning. However, there is a marked delay in cathepsin D activity since it does not increase until 2 days post-weaning and remains high thereafter. In order to find out whether nitration of cathepsin D regulates its activity, iNOS (inducible nitric oxide synthase)−/− mice were used. The expression…

Cationic amino acid transport across the blood-brain barrier is mediated exclusively by system y+.

Cationic amino acid (CAA) transport is brought about by two families of proteins that are found in various tissues: Cat (CAA transporter), referred to as system y+, and Bat [broad-scope amino acid (AA) transporter], which comprises systems b0,+, B0,+, and y+L. CAA traverse the blood-brain barrier (BBB), but experiments done in vivo have only been able to examine the BBB from the luminal (blood-facing) side. In the present study, plasma membranes isolated from bovine brain microvessels were used to identify and characterize the CAA transporter(s) on both sides of the BBB. From these studies, it was concluded that system y+was the only transporter present, with a prevalence of activity on the…

Liver intracellular L-cysteine concentration is maintained after inhibition of the trans-sulfuration pathway by propargylglycine in rats.

To study the fate ofl-cysteine and amino acid homeostasis in liver after the inhibition of the trans-sulfuration pathway, rats were treated with propargylglycine (PPG). At 4 h after the administration of PPG, liver cystathionase (EC4.4.1.1) activity was undetectable,l-cystathionine levels were significantly higher,l-cysteine was unchanged and GSH concentration was significantly lower than values found in livers from control rats injected intraperitoneally with 0.15 M-NaCl. The hepatic levels of amino acids that are intermediates of the urea cycle,l-ornithine,l-citrulline andl-arginine and blood urea were significantly greater. Urea excretion was also higher in PPG-treated rats when compared…

Retinoids induce MMP-9 expression through RARalpha during mammary gland remodeling.

Retinoic acid (RA) is a signaling molecule in the morphogenesis of the mammary gland, modulating the expression of matrix metalloproteinases (MMPs). The aim of this paper was to study the role of RA during weaning, which consists of three events: apoptosis of the secretory cells, degradation of the extracellular matrix, and adipogenesis. CRABP II and CRBP-1 carrier proteins increased significantly during weaning compared with lactating glands but reverted to control values after the litter resuckled. The effects of RA are mediated by the nuclear receptors RARalpha, RARbeta, RARgamma, and RXRalpha, which underwent an increase in protein levels during weaning. In an attempt to elucidate the R…

NF-ĸB as node for signal amplification during weaning.

Post-lactational involution has been reported to share common features with breast tumor development. A deep characterization of the signaling triggered after weaning would help to unveil the complex relationship between involution and breast cancer. NF-κB, a crucial factor in the involuting gland, might be an important regulatory node for signal amplification after weaning; however there is limited information about the identity of NF-κB-target genes and the molecular mechanisms leading to the selection of genes involved in a particular biological process. We identified 4532 target genes in mammary gland at 48h weaning, by genome-wide analysis of regions bound by RelA(p65)-NF-κB in vivo. I…

Maintenance of GSH content in primary astrocyte cultures under oxidative stress conditions.

Co-administration of pentoxifylline and thiopental causes death by acute pulmonary oedema in rats

Background and purpose: Pentoxifylline exhibits rheological properties that improve microvascular flow and it is widely used in vascular perfusion disorders. It also exhibits marked anti-inflammatory properties by inhibiting tumour necrosis factor a production. Thiopental is one of the most widely used drugs for rapid induction of anaesthesia. During experimental studies on the treatment of acute pancreatitis, we observed that when pentoxifylline was administered after anaesthesia with thiopental, most of the rats exhibited dyspnea, signs of pulmonary oedema and died. The aim of the work described here was to investigate the cause of the unexpected toxic effect of the combined treatment wit…

Circulating mononuclear cells nuclear factor-kappa B activity, plasma xanthine oxidase, and low grade inflammatory markers in adult patients with familial hypercholesterolaemia.

Eur J Clin Invest 2010; 40 (2): 89–94 Abstract Background  Few data are available on circulating mononuclear cells nuclear factor-kappa B (NF-kB) activity and plasma xanthine oxidase (XO) activity in heterozygous familial hypercholesterolaemia (FH). The goal of the study was to analyse circulating mononuclear cells NF-kB and plasma XO activities in FH patients. Materials and methods  Thirty FH index patients and 30 normoglycaemic normocholesterolaemic controls matched by age, gender, body mass index, abdominal circumference and homeostasis model assessment index were studied. Plasma XO and inflammatory markers were measured by standard methods. NF-kB was assayed in circulating mononuclear c…

Excitotoxicity in AD is partially caused by the inactivation of APC/C-Cdh1 E3 Ubiquitin Ligase

Role of the gamma-glutamyl cycle in the regulation of amino acid translocation

Amino acid translocation was studied in the mammary gland of lactating rats and in the placenta of pregnant rats. The uptake of amino acids by the mammary gland is maximal on days 10-14 of lactation and is minimal on days 19-21. However, on day 19 maximal uptake can be restored by injection of 1) small amounts of gamma-glutamyl amino acids, 2) 5-oxoproline, and 3) an inhibitor of 5-oxoprolinase. A severe decrease in uptake of amino acids at the peak of lactation is provoked by anthglutin, an inhibitor of gamma-glutamyltranspeptidase (GGT). Simultaneous injection of 5-oxoproline blocks these effects of anthglutin. In pregnant rats, inhibition (79%) of placental GGT activity by acivicin resul…

AZT treatment induces molecular and ultrastructural oxidative damage to muscle mitochondria. Prevention by antioxidant vitamins.

AIDS patients who receive zidovudine (AZT) frequently suffer from myopathy. This has been attributed to mitochondrial (mt) damage, and specifically to the loss of mtDNA. This study examines whether AZT causes oxidative damage to DNA in patients and to skeletal muscle mitochondria in mice, and whether this damage may be prevented by supranutritional doses of antioxidant vitamins. Asymptomatic HIV-infected patients treated with AZT have a higher urinary excretion (355+/-100 pmol/kg/d) of 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxo-dG) (a marker of oxidative damage to DNA) than untreated controls (asymptomatic HIV-infected patients) (182+/-29 pmol/kg/d). This was prevented (110+/-79 pmol/kg/d)…

Retinol, at concentrations greater than the physiological limit, induces oxidative stress and apoptosis in human dermal fibroblasts

We have investigated the dose (in the range of microM) and time-dependent effects of four different retinoids (retinol, retinal, retinoic acid and retinol palmitate) on human dermal fibroblasts cultivated in vitro. Retinol and retinal, at a concentration of 20 microM, caused cell damage as evaluated by lactate dehydrogenase activity released into the culture medium. The oxidised glutathione (GSSG)/reduced glutathione (GSH) ratio and malondialdehyde production indicated that 20 microM of retinol provoked oxidative stress in the cultivated human fibroblasts. In the first 8 h after retinol treatment the levels of p53 and Bax proteins as well as caspase 3 activity increased, suggesting apoptoti…

P674Metabolic deregulation in myocardial infarction is mediated by PGC-1 alpha pathway

Purpose: In the context of myocardial infarction (MI) the availability of metabolites is clearly restricted, therefore a fuel metabolic shifts takes place. Previous studies have indicated that peroxisome proliferator activated receptor co-activator alpha (PGC-1α) pathway is a crucial regulator of cardiac metabolism in response to cardiac stress. Here we address the role of PGC-1α in regulating metabolic changes of MI. Methods: We studied a group of 12 common swine in which anterior MI was induced by means of angioplasty balloon inflation. A series of 6 swine were sacrificed at 48h post-infarction (acute infarction group) and another series of 6 swine were sacrificed at 3 weeks (chronic infa…

Role of GSH in the modulation of NOS-2 expression in the weaned mammary gland

GSH delivery to the lactating mammary gland is essential for the maintenance of lactation as its decrease leads to apoptosis and involution of the mammary gland. In fact, it has already been demonstrated that some of the changes in gene expression found in the lactating mammary gland after forced weaning are reproduced in rats treated with buthionine sulphoximine to deplete GSH levels. An oligonucleotide microarray experiment would give us a better knowledge of the mRNA expression patterns during lactation and after weaning and the possible functions of GSH in the modulation of these events.

Centenarians: An excellent example of resilience for successful ageing.

Centenarians are remarkable not only because of their prolonged life, but also because they compress morbidity until the very last moments of their lives, thus being proposed as a model of successful, extraordinary ageing. From the medical viewpoint, centenarians do not escape the physiological decline or the age-related diseases or syndromes (i.e. frailty), but the rate of such processes is slow enough to be counterbalanced by their increased intrinsic capacity to respond to minor stresses of daily life (i.e. resilience). These new concepts are reviewed in this paper. Allostatic stresses lead to a chronic low-grade inflammation that has led to the proposal of the "inflammaging" theory of a…

The Relationship between Alcohol–induced Apoptosis and Oxidative Stress in the Liver

This chapter discusses the relationship of apoptosis and oxidative stress induced by alcohol in the liver. Oxidative stress is involved in the pathogenesis and progression of alcohol-induced liver disease. Chronic alcoholism always causes oxidative stress independently of the presence of liver disease. Two key mechanisms are responsible for it: (1) the mitochondrial respiratory chain and (2) cytochrome P450 2El activity. Increased production of reactive oxygen species at complexes I and III together with NADH overproduction would be the major cause for mitochondrial oxidative stress in chronic alcoholism. Reactive Oxygen Species (ROS) cause oxidative damage, which may lead to cell death by …

CENTENARIANS TRANSCRIPTOME IS UNIQUE AND REVEALS A ROLE OF BCL-XL IN SUCCESSFUL AGING

Centenarians not only enjoy an extraordinary aging, but also show a compression of morbidity. We identified 1721 mRNAs differentially expressed by PMBCs from centenarians when compared with septuagenarians and young people. Sub-network analysis led us to identify Bcl-xL as an important gene up-regulated in centenarians. We found that centenarians display lower plasma cytochrome C levels, higher mitochondrial membrane potential and also less cellular damage accumulation. Immune function is significantly impaired in septuagenarians compared with young people whereas centenarians maintain it. To further ascertain the functional role of Bcl-xL in cellular aging, we found in transduced lymphocyt…

Calpains mediate epithelial-cell death during mammary gland involution: mitochondria and lysosomal destabilization.

Our aim was to elucidate the physiological role of calpains (CAPN) in mammary gland involution. Both CAPN-1 and -2 were induced after weaning and its activity increased in isolated mitochondria and lysosomes. CAPN activation within the mitochondria could trigger the release of cytochrome c and other pro-apoptotic factors, whereas in lysosomes it might be essential for tissue remodeling by releasing cathepsins into the cytosol. Immunohistochemical analysis localized CAPNs mainly at the luminal side of alveoli. During weaning, CAPNs translocate to the lysosomes processing membrane proteins. To identify these substrates, lysosomal fractions were treated with recombinant CAPN and cleaved produc…