Neurodegenerative diseases and oxidative stress.

Oxidative stress is now recognized as accountable for redox regulation involving reactive oxygen species (ROS) and reactive nitrogen species (RNS). Its role is pivotal for the modulation of critical cellular functions, notably for neurons astrocytes and microglia, such as apoptosis program activation, and ion transport, calcium mobilization, involved in excitotoxicity. Excitotoxicity and apoptosis are the two main causes of neuronal death. The role of mitochondria in apoptosis is crucial. Multiple apoptotic pathways emanate from the mitochondria. The respiratory chain of mitochondria that by oxidative phosphorylation, is the fount of cellular energy, i.e. ATP synthesis, is responsible for most of ROS and notably the first produced, superoxide anion (O(2)(;-)). Mitochondrial dysfunction, i.e. cell energy impairment, apoptosis and overproduction of ROS, is a final common pathogenic mechanism in aging and in neurodegenerative disease such as Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). Nitric oxide (NO(;)), an RNS, which can be produced by three isoforms of NO-synthase in brain, plays a prominent role. The research on the genetics of inherited forms notably ALS, AD, PD, has improved our understanding of the pathobiology of the sporadic forms of neurodegenerative diseases or of aging of the brain. ROS and RNS, i.e. oxidative stress, are not the origin of neuronal death. The cascade of events that leads to neurons, death is complex. In addition to mitochondrial dysfunction (apoptosis), excitotoxicity, oxidative stress (inflammation), the mechanisms from gene to disease involve also protein misfolding leading to aggregates and proteasome dysfunction on ubiquinited material.

Could antioxidant supplementation reduce antiretroviral therapy-induced chronic stable hyperlactatemia?

OBJECTIVE: To determine if asymptomatic stable chronic hyperlactatemia in human immunodeficiency virus (HIV)-infected patients under highly active antiretroviral therapy (HAART, including nucleoside analog reverse transcriptase inhibitors (NRTI)) could be improved by antioxidant supplementation. DESIGN: To match two groups of patients taking NRTI for at least 24 months: 15 without and 15 with antioxidant supplementation (vitamin E, beta-carotene, N-acetylcysteine, selenium, Gingko biloba extracts and nutritional supplements). For both the groups, the supplementation by antioxidants or its lack was carefully assessed. Venous lactatemia, blood oxidative stress markers (plasma lipid peroxidation, enzymatic and non-enzymatic antioxidants), CDC revisited classification, CD4 count and viral load, NRTI (with or without stavudine) and other antiretroviral drugs used, lipoatrophy, central fat accumulation were assessed. RESULTS: Patients were not statistically different with respect to the CDC classification, CD4 count, viral load and characteristics of antiretroviral therapy. Blood oxidative stress markers, i.e. vitamin E, vitamin A and beta-carotene tended to be higher in the supplemented group. The difference observed in venous lactate concentration between the two groups was significant (1.37 +/- 0.10 vs. 1.82 +/- 0.19 mmol/l in the supplemented and non-supplemented groups, respectively P = 0.04). CONCLUSION: Antioxidant supplementation improves the asymptomatic stable chronic hyperlactatemia observed in HIV-infected patients taking HAART including NRTI for a long time. Controlled studies are needed to demonstrate the efficacy of this supplementation on mitochondrial toxicity observed during HAART and the possible usefulness of its combination with mitochondrial cofactors like carnitine, riboflavine, coenzyme Q, alpha-lipoic acid.

Iron metabolism, free radicals, and oxidative injury.

Iron has the capacity to accept and donate electrons readily. This capability makes it physiologically essential, as a useful component of cytochromes and oxygen-binding molecules. However, iron is also biochemically dangerous; it can damage tissues by catalyzing the conversion of hydrogen peroxide to free-radical ions that attack cellular membranes, protein and DNA. This threat is reduced in the healthy state where, because of the fine iron metabolism regulation, there is never appreciable concentration of 'free iron'. Under pathological conditions, iron metabolism and superoxide metabolism are clearly interactive. Each can exacerbate the toxicity of the other. Iron overload may amplify the damaging effects of superoxide overproduction in a very broad spectrum of inflammatory, both acute and chronic, conditions. Furthermore, chronic oxidative stress may modulate iron uptake and storage, leading to a self-sustained and ever-increasing spiral of cytotoxic and mutagenic events. The iron chelator deferroxamine is able to chelate 'free iron' even inside the cell. Its regular clinical use is to promote the excretion of an iron overload, when phlebotomy is harmful, and the dosage varies between 2-10 g/d. In conditions where deferroxamine is used to prevent the iron-driven oxygen toxicity, i.e., acute or chronic inflammatory diseases with oxidative stress, the dosage can be extremely reduced and the addition of antioxidants could be useful.

[Neuro-degenerative diseases: role of reactive oxygen species and of apoptosis]. / Maladies neurodégénératives: rôle des espèces activées de l'oxygène et de l'apoptose.

NEURON DEATH: Major progress in our understanding of the pathophysiology of neurodegenerative diseases has greatly benefited from the convergence between work devoted to reactive oxygen species (including nitric oxide) and programmed cell death, or apoptosis, and exitotoxicity. LATERAL AMYOTROPHIC SCLEROSIS: The discovery of a mutation in the copper-zinc superoxide dismutase gene in patients with lateral amyotrophic sclerosis has made it possible to analyze the events leading to neuron death in transgenic mice. An overload of reactive oxygen species accelerates apoptosis and oxidative stress is implicated in excitotoxicity which is a hyperstimulation of excitatory amino acides (glutamate, aspartate) producing neuron death. OTHER CHRONIC CONDITIONS: Based on evidence from the mouse model, apoptosis, excitotoxicity and oxygenated free radicals could play a causal role in other neurodegenerative diseases including HIV-related encephalopathy, Parkinsonís disease and Alzheimerís disease.

[Study of oxidative stress in the elderly]. / Etude du stress oxydant chez le sujet agé.

OBJECTIVES: Determine the oxidative stress status and its significance in elderly subjects. METHODS: Six parameters marking oxidative stress evaluated in 52 elderly patients (mean age 85 +/- 6 years; range 74 to 98) admitted to a medium-term and long-term nursing home (n = 30) or a hospital ward (n = 22) were compared with those in 30 disease-free young subjects (age range 20-40 years). Plasma levels of thiobarbituric acid reactive substances vitamin E and selenium and activity of free-radical protective enzymes (erythrocyte superoxide dismutase, plasma and erythrocyte glutathione peroxidase) were assessed. RESULTS: Thiobarbituric acid reactive substances were higher and superoxide dismutase, erythrocyte and plasma glutathione peroxidase, and plasma selenium were lower in elderly patients than in young controls. There was no difference in vitamin E levels. In the nursing home population, erythrocyte superoxide dismutase was correlated with erythrocyte glutathione peroxidase and vitamin E, plasma glutathione peroxidase with erythrocyte glutathione peroxidase, vitamin E and selenium and erythrocyte g peroxidase, vitamin E and selenium and erythrocyte glutathione peroxidase with vitamin E. Only the correlation between erythrocyte and plasma glutathione peroxidase was found in the hospitalized population. These levels remained unchanged for a 30 day period in individual patients. CONCLUSION: "Oxidative stress" assessed by six parameters was thus observed in the elderly population and could be considered as a "biological marker of ageing". Supplementation with selenium or other anti-oxidants could be proposed.

[Oxidative stress in 29 HIV seropositive patients. Two-year results of a double-blind trial of diethyldithiocarbamate versus placebo]. / Stress oxydatif chez 29 sujets séropositifs. Résultats à 2 ans d'une étude en double insu diéthyldithiocarbamate versus placebo.

Among 29 seropositive subjects who had participated in the HIV 87 therapeutic trial (Mérieux laboratories), the oxidative stress was evaluated at 24 months in 16 treated with diethyldithiocarbamate (dithiocarb) and in 13 who had received the placebo. No significant difference was found between these two groups, whereas the existence of an oxidative stress has been confirmed in seropositive subjects compared with controls.

[Pancreatic endocrine tumor with metastases and increase of alpha-fetoprotein. A case report]. / Tumeur endocrine pancréatique avec métastases et élévation de l'alpha-foetoprotéine. A propos d'un cas.

The authors report the case of a 48 years old man presenting a pancreatic islet cell carcinoma (gastrinoma) with liver, nodes and peritoneal metastases, associated with an elevated alpha-fetoprotein (AFP) concentration. Incomplete remission was first obtained with a chemotherapy using Streptozotocin combined with 5-Fluorouracil, in association with a Somatostatin analogue (SMS 201-995). But when relapses occur, another chemotherapy was not so effective. Serum gastrin and AFP levels had the same evolution and appear to have the same interest to follow the course of the disease.

[Oxygenated free radicals and vascular pathology]. / Radicaux libres oxygénés et pathologie vasculaire.

Oxygen free radicals are used as a weapon by neutrophil morphopolynuclear cells, monocytes and macrophages against bacterial attacks. They do interact with arachidonic acid cascade catabolism that means they stimulate too, platelet cells and endothelial cells activity (EDRF is indeed "NO"). They prime all along inflammatory process and thrombosis which are main items of the pathology of vessels.

[Free radicals and lipid peroxidation in cell biology: physiopathologic prospects]. / Radicaux libres et peroxydation lipidique en biologie cellulaire: perspectives physio-pathologiques.

Oxygen derived free radicals (OFR) arise in the course of normal cellular life, especially during cellular respiration. They are formed when molecular oxygen is reduced to water. These highly reactive species are controlled by a protective system both enzymatic and non enzymatic which helps to prevent the accumulation of peroxidative damage to the cell. Lipid peroxides result from the reaction of oxygen derived free radicals with polyinsatured fatty acids of membranes phospholipids and can be formed both non enzymatically and enzymatically (eicosanoids). Oxygen derived free radicals attack over-running beyond the protective system leads to oxidative stress. The cells involved in inflammation (polymorphonuclear, leucocytes, monocytes, platelets, endothelial cells) release oxygen derived free radicals and lipid peroxides and inflammatory diseases of infectious or non infectious origin can be considered as oxidative stress. Intracellular oxidative stress can lead to cellular death or trigger a strong inflammatory reaction. This occurs during ischemia reperfusion injury and hyperoxia. Exposure to ionizing radiation results in overproduction of oxygen derived free radicals both extra and intracellular. Oxidative stress may be involved in atheroma (where oxidised LDL are described), ageing and cancer.

[Anonymous and free-of-charge detection of human immunodeficiency virus infection. 20-months' experience at a center]. / Dépistage anonyme et gratuit de l'infection par le virus de l'immunodéficience humaine. Expérience d'un centre pendant 20 mois.

The results of 20 months' activity of the anonymous and free-of-charge detection centre of the Pitié-Salpêtrière hospital group, Paris, concerning human immunodeficiency virus infection (HIV) are presented. During that period, 3,480 persons consulted and 3,332 anonymous questionnaires were filled and returned: 20.5 percent of the subjects were homosexuals, 6.5 percent were drug-addicts and 73 percent were non drug-addict heterosexuals; 31 percent used condoms. A total of 3,398 blood samples were collected; 232 sera were positive or undetermined for HIV-1 and/or HIV-2 by the ELISA method; 132 Western Blot tests confirmed the positivity for HIV-1 but not for HIV-2. The overall serum positivity was 4 percent; 18.3 percent of drug-addicts, 9.5 percent of homosexuals and 0.9 percent of heterosexuals were HIV positive. Among seropositive subjects, 51 percent were homosexuals, 27 percent were drug-addicts, 4 percent were homosexual drug-addicts and 18 percent were heterosexuals (43 percent of these had had multiple partners); condoms were used by 59 percent of HIV positive subjects. The percentage of HIV positive subjects in our series was lower than that estimated in populations at risk (drug-addicts 50 percent, homosexuals 32 percent); it was similar to the percentages found in other detection centres (5 to 6 percent). Most seropositive patients belong to the category of persons who are the first to be struck by HIV. The heterosexual population is relatively spared, but most of the recent seroconversions have occurred in this group.

Phase II trial of copper zinc superoxide dismutase (CuZn SOD) in the treatment of Crohn's disease.

Bovine Cu Zn SOD was used during an 8 year period as an antiinflammatory drug in 26 patients with severe Crohn's disease (CDAI 300) usually after failure of corticotherapy or when this drug was discontinued because of side effects or infection. This was a phase II trial during which doses routes of administration and concomitant therapies were progressively modified. We obtained 73% good short term responses (judged upon CDAI and anatomic healing) and 82% positive results on long term evolution (the criteria were: i CDAI lower than 100 in between relapses, ii complete healing or notable improvement of lesions, iii no surgery needed, iv return to work. The acceptability was excellent with the free enzyme. Since the above described experience, published in Free Radical Biology and Medicine (1989, 7: 145-151), we used always the same treatment schedule (SOD 8 mg/day associated with Desferroxamine--500 mg subcutaneous every 2 days). The follow-up during the 87-89 period showed that 12 are in good health without any relapse, 9 experienced one or more relapses, and showed good responses upon resumption of treatment, 5 failed to respond to treatment, all part of the initial group on which SOD treatment had already failed, and among whom 3 were lost for follow-up before 1987, and two others took up another SOD treatment which also failed. 3 new patients (2 females, 1 male) were treated since then, and all 3 had positive results (one with disappearance of ileocoecal mass). The efficacy of SOD as an antiinflammatory drug in Crohn's disease needs to be confirmed by controlled trials.

The evolution of oxidative stress indicators in the course of myocardial ischemia.

Two studies were carried out in patients suffering from Unstable Angina (UA) and Myocardial Infarction (MI). The first study investigated the variations of the Malondialdehyde (MDA) rate at 1st, 5th, 12th day of treatment in 27 patients (15 UA and 12 MI), compared to 15 controls. This rate varied in a different way, with a first peak and a rapid decrease in UA, where it regularly decreases in MI. The second study focused on the variations of MDA, Superoxide Dismutase (SOD), Glutathion Peroxydase (GPX) rates at 2nd, 12th days in 53 patients (19 UA and 34 MI), compared to 35 controls. Here again, the rate of MDA was high on day 2 and decreased on day 12. The rate of GPX showed similar evolution while the SOD rate had an opposite evolution. These two studies confirm the evidence of oxidative stress in acute coronary deficiency.

[Nailfold capillaroscopy. Comparison of 100 subjects over 65 years of age and of 100 young adults]. / Capillaroscopie periungueale. Comparaison de 100 sujets âgés de plus de 65 ans et de 100 adultes jeunes.

Nailfold capillary microscopy patterns in 100 patients aged more than 65 years and free from inflammatory diseases were compared to those of 100 young healthy adults. A higher prevalence of arteriovenous sludge (36% vs 7%, p less than 10(-6)), increase in capillary loop length (12% vs. 0%, p less than 10(-3)) and especially prominent subpapillary plexus (63% vs 12%, p less than 10(-9)) was found in the geriatric group. Such capillary patterns cannot be considered as abnormal in patients aged more than 65 years. Enlargement of capillary loops and loss of capillaries were never encountered. Bushy capillary formations and hemorrhages were very uncommon in both groups.

Distribution of thiobarbituric acid-reactive substances in lipoproteins and proteins in serum.

We assessed the distribution of malondialdehyde (MDA) in lipoproteins and proteins in serum after using two procedures to separate the lipoproteins: sequential ultracentrifugation or selective precipitation with a sodium phosphotungstate and magnesium chloride reagent followed by ultracentrifugation of the supernate. MDA concentrations were determined by the thiobarbituric acid reaction and quantified by fluorometry. We found that 43% of the thiobarbituric acid-reactive substances (TBARS) was bound to the lipoproteins--27% to very-low- and low-density lipoproteins (VLDL-LDL) and 16% to high-density lipoproteins (HDL)--and from 11.5% to 15.8% to proteins, depending on the separation procedure. Residual unbound TBARS were located in the ultracentrifugation layers that contained no lipoproteins or proteins. The TBARS concentration in serum lipoproteins containing apolipoprotein B (i.e., VLDL-LDL) was the same after ultracentrifugation or selective precipitation. We therefore consider the precipitation method more suitable for routine TBARS determination in these lipoproteins, because it is easier to handle and faster. However, for determination of TBARS in HDL, selective precipitation requires subsequent ultracentrifugation at a density of 1.21 kg/L.

[Oxygen free radicals and inflammatory diseases of intestines]. / Les radicaux libres oxygénés (RLO) et maladies inflammatoires de l'intestin (MII).

Free oxygen radicals (F.O.R.) belong to a very aggressive chemical species derived from molecular oxygen. Their role in inflammation is well established and Polymorphonuclear neutrophils (PMNS) make use of them as antibacterial weapons. Their role has been experimentally demonstrated in numerous ischemia-reperfusion models. Free radical scavengers such as the superoxide dismutase, allopurinol or desferrioxamine can prevent the occurrence of lesions. The essential role of PMNS in these models is demonstrated by the fact that previous depletion of the animal in PMNS also prevents such lesions. Histologically, in these ischemia-reperfusion models, PMNS infiltration may be quantified by assay of myeloperoxidase. In experimental models of inflammatory colitis (acetic acid, bacterial polysaccharides) intestinal wall infiltration by PMNS is a fundamental phenomenon and is also a characteristic of Crohn's disease and exacerbations of Ulcerative Colitis. Thus, it is probable in both disorders that F.O.R. play an important role since steroids inhibit their secretion by PMNS and 5-aminosalicylic acid has been shown to be a F.O.R. scavenger.

[Role of lipid peroxidation in the formation of atheroma]. / Rôle de la peroxydation lipidique dans la constitution de la plaque d'athérome.

The demonstration that lipid peroxidation (enzymatic or non enzymatic oxidation of polyunsaturated fatty acids) is involved and plays a pathophysiological role (in relation to the metabolic pathways of prostaglandins, leukotrienes and to others inflammation-related events) in the initiation of arteriosclerotic plaques is a breakthrough in the pathogenesis of atheroma. Macrophages play a central role in this mechanism. Indeed foam cells are macrophages loaded with oxidized low density lipoproteins (LDL). These oxidized LDL are preferentially recognized by macrophages thanks to their scavenger receptor. The role of such foam cells in the initiation and development of atheroma is well known. The formation of arteriosclerotic plaques results in important endothelial alterations, and endothelial cells lose their protective ability to prevent platelet aggregation and related thrombotic events. Inflammation and thrombosis are overlapping phenomena which are mediated by common cells (platelets, polymorphonuclear leucocytes, monocytes, macrophages, endothelial cells). During the activation of such inflammatory cells a number of eicosanoids are produced, and the profile of such metabolites is largely controlled by cellular interactions. In addition these inflammatory cells have the ability to produce oxygen free radicals, and initiate non enzymatic lipid peroxidation.

Phase II trial of copper zinc superoxide dismutase (CuZnSOD) in treatment of Crohn's disease.

Bovine CuZnSOD was used during an 8-year period as an anti-inflammatory drug in 26 patients with severe Crohn's disease, usually after failure of corticotherapy, or when this drug was avoided because of side-effects or abscesses. This was a Phase II trial during which doses, routes of administration and concomitant therapies were progressively modified. The acceptability was excellent with the free enzyme. We obtained 19/26 very good short term responses, and 82% good results on long term evolution. The efficacy of SOD as an anti-inflammatory drug in Crohn's disease needs to be confirmed by controlled trials.

[Prolonged delta antigen in the blood without occurrence of anti-delta antibodies in 2 immunosuppressed patients]. / Antigénémie delta prolongée sans apparition d'anticorps anti-delta chez deux patients immunodéprimés.

Delta coinfection or superinfection in a patient with chronic hepatitis B is characterized by a very transient delta antigenemia and an early seroconversion of IgM to IgG anti-delta. The persistent expression of delta antigen in the liver can be associated with acute, severe, or chronic hepatitis. In our two patients, delta antigenemia persisted respectively 10 weeks and 14 months with aggravation of liver histopathologic lesions without seroconversion. Such a serologic profile during delta infection does not seem to have been reported previously. These two cases concerned two patients with an important immunosuppression, one by a major immunosuppressive therapy and HIV superinfection, the other by an acquired immunodeficiency syndrome. The cytotoxic effect of delta virus in such circumstances is discussed.