Cerebrospinal fluid levels of superoxide dismutases in neurological diseases detected by sensitive enzyme immunoassays

A beginner's guide into curated analyses of open access datasets for biomarker discovery in neurodegeneration

The discovery of surrogate biomarkers reflecting neuronal dysfunction in neurodegenerative diseases (NDDs) remains an active area of research. To boost these efforts, we demonstrate the utility of publicly available datasets for probing the pathogenic relevance of candidate markers in NDDs. As a starting point, we introduce the readers to several open access resources, which contain gene expression profiles and proteomics datasets from patient studies in common NDDs, including proteomics analyses of cerebrospinal fluid (CSF). Then, we illustrate the method for curated gene expression analyses across select brain regions from four cohorts of Parkinson disease patients (and from one study in common NDDs), probing glutathione biogenesis, calcium signaling and autophagy. These data are complemented by findings of select markers in CSF-based studies in NDDs. Additionally, we enclose several annotated microarray studies, and summarize reports on CSF proteomics across the NDDs, which the readers can utilize for translational purposes. We anticipate that this "beginner's guide" will benefit the research community in NDDs, and would serve as a useful educational tool.

Does wild-type Cu/Zn-superoxide dismutase have pathogenic roles in amyotrophic lateral sclerosis?

Amyotrophic lateral sclerosis (ALS) is characterized by adult-onset progressive degeneration of upper and lower motor neurons. Increasing numbers of genes are found to be associated with ALS; among those, the first identified gene, SOD1 coding a Cu/Zn-superoxide dismutase protein (SOD1), has been regarded as the gold standard in the research on a pathomechanism of ALS. Abnormal accumulation of misfolded SOD1 in affected spinal motor neurons has been established as a pathological hallmark of ALS caused by mutations in SOD1 (SOD1-ALS). Nonetheless, involvement of wild-type SOD1 remains quite controversial in the pathology of ALS with no SOD1 mutations (non-SOD1 ALS), which occupies more than 90% of total ALS cases. In vitro studies have revealed post-translationally controlled misfolding and aggregation of wild-type as well as of mutant SOD1 proteins; therefore, SOD1 proteins could be a therapeutic target not only in SOD1-ALS but also in more prevailing cases, non-SOD1 ALS. In order to search for evidence on misfolding and aggregation of wild-type SOD1 in vivo, we reviewed pathological studies using mouse models and patients and then summarized arguments for and against possible involvement of wild-type SOD1 in non-SOD1 ALS as well as in SOD1-ALS.

Influence of Bone Marrow-Derived Mesenchymal Stem Cell Therapy on Oxidative Stress Intensity in Minimally Conscious State Patients

Neurological disorders, including minimally conscious state (MCS), may be associated with the presence of high concentrations of reactive oxygen species within the central nervous system. Regarding the documented role of mesenchymal stem cells (MSCs) in oxidative stress neutralization, the aim of this study is to evaluate the effect of bone marrow-derived MSC (BM-MSC) transplantation on selected markers of oxidative stress in MCS patients. Antioxidant capacity was measured in cerebrospinal fluid (CSF) and plasma collected from nine patients aged between 19 and 45 years, remaining in MCS for 3 to 14 months. Total antioxidant capacity, ascorbic acid and ascorbate concentrations, superoxide dismutase, catalase, and peroxidase activity were analyzed and the presence of tested antioxidants in the CSF and plasma was confirmed. Higher ascorbic acid (AA) content and catalase (CAT) activity were noted in CSF relative to plasma, whereas superoxide dismutase (SOD) activity and total antioxidant capacity were higher in plasma relative to CSF. Total antioxidant capacity measured in CSF was greater after BM-MSC transplantations. The content of ascorbates was lower and CAT activity was higher both in CSF and plasma after the administration of BM-MSC. The above results suggest that MSCs modulate oxidative stress intensity in MCS patients, mainly via ascorbates and CAT activity.

Differential Protein Profiling of Cerebrospinal Fluid in Piglets with Severe Meningoencephalitis Caused by Streptococcus suis Type 2 Compared to Controls

Streptococcus suis serotype 2 (SS2) is a zoonotic pathogen that can cause meningitis both in pigs and in human beings. However, the pathogenesis of central nervous system (CNS) infection caused by SS2 have not yet been elucidated. To find the key molecules in cerebrospinal fluid (CSF) needed for the pathogenesis, a SS2 meningoencephalitic pig model and a SS2 non-meningoencephalitic pig model were established in this study. CSF was collected from infected piglets, and protein profiling was performed with label-free proteomics technology. A total of 813 differential proteins, including 52 up-regulated proteins and 761 down-regulated proteins, were found in the CSF of meningoencephalitic pigs compared with both non-meningoencephalitic pigs and healthy pigs. These 813 differential proteins were clustered into three main categories, namely, cellular component, biological process, and molecular function by gene ontology (GO) analysis. The most enriched subclasses of differential proteins in each category were exosome (44.3%), energy pathway (25.0%) and catalytic activity (11.3%), respectively. The most enriched subclasses of upregulated proteins were extracellular (62.1%), protein metabolism (34.5%) and cysteine-type peptidase activity (6.9%), and of downregulated proteins were exosomes (45.0%), energy pathway (24.0%) and catalytic activity (9.4%). Then, the differential proteins were further investigated by using the KEGG database and were found to participate in 16 KEGGs. The most enriched KEGG was citrate cycle (56.6%), and some of these differential proteins are associated with brain diseases such as Huntington's disease (18.6%), Parkinson's disease (23.8%) and Alzheimer's disease (17.6%). Sixteen of the 813 differential proteins, chosen randomly as examples, were further confirmed by enzyme-linked immunosorbent assay (ELISA) to support the proteomic data. To our knowledge, this is the first study to analyze the differential protein profiling of CSF between SS2 meningoencephalitic piglets and non-meningoencephalitic piglets by employing proteomic technology. The discovery and bioinformatics analysis of these differential proteins provides reference data not only for research on pathogenesis of SS2 CNS infection but also for diagnosis and drug therapy research.

Oxidative stress in cerebral small vessel disease. Role of reactive species

Cerebral small vessel disease (CSVD) is a wide term describing the condition affecting perforating arterial branches as well as arterioles, venules, and capillaries. Cerebral vascular net is one of the main targets of localised oxidative stress processes causing damage to vasculature, changes in the blood flow and blood-brain barrier and, in consequence, promoting neurodegenerative alterations in the brain tissue. Numerous studies report the fact of oxidation to proteins, sugars, lipids and nucleic acids, occurring in most neurodegenerative diseases mainly in the earliest stages and correlations with the development of cognitive and motor disturbances. The dysfunction of endothelium can be caused by oxidative stress and inflammatory mechanisms as a result of reactions and processes generating extensive reactive oxygen species (ROS) production such as high blood pressure, oxidised low density lipoproteins (oxLDL), very low density lipoproteins (vLDL), diabetes, homocysteinaemia, smoking, and infections. Several animal studies show positive aspects of ROS, especially within cerebral vasculature.

Oxidative Stress and Neurobiology of Demyelination

Despite a large amount of research which aims at defining the pathophysiology of human demyelination (i.e., multiple sclerosis), etiological bases of disease have been unknown so far. The point of intersection of all assumed etiological factors, which are mainly based upon immunological cascades, is neuroinflammation. The precise definition of the place and role of all pathogenetic factors in the occurrence and development of the disease is of crucial importance for understanding the clinical nature and for finding more effective therapeutic options. There are few studies whose results give more precise data about the role and the importance of other factors in neuroinflammation, besides immunological ones, with regard to clinical and paraclinical correlates of the disease. The review integrates results found in previously performed studies which have evaluated oxidative stress participation in early and late neuroinflammation. The largest number of studies indicates that the use of antioxidants affects the change of neuroinflammation course under experimental conditions, which is reflected in the reduction of the severity and the total reversibility in clinical presentation of the disease, the faster achieving of remission, and the delayed and slow course of neuroinflammation. Therapies based on the knowledge of redox biology targeting free radical generation hold great promise in modulation of the neuroinflammation and its clinical presentations.

Cerebrospinal fluid and plasma oxidative stress biomarkers in different clinical phenotypes of neuroinflammatory acute attacks. Conceptual accession: from fundamental to clinic

Oxidative stress is revealed as the main contributor in the pathophysiology of neuroinflammation. Analyzing plasma and cerebrospinal fluid (CSF) of patients with different clinical phenotypes of neuroinflammation, defined as clinically isolated syndrome (CIS), and those defined as relapsing remitting multiples sclerosis (RRMS), we tested peripheral and CNS oxidative stress intensity in these neuroinflammatory acute attacks. All obtained values changes were assessed regarding clinical and radiological features of CNS inflammation. The obtained results revealed an increase in malondialdehyde levels in plasma and CSF in CIS and RRMS patients compared to control values (p < 0.05). The obtained values were most prevailed in both study group, CIS and RRMS, in patients with severe clinical presentation (p < 0.05). Measured activities of catalase and total superoxide dismutase were higher in CIS and RRMS patients in plasma compared to control values (p < 0.05), parallel with an increased catalase activity and decrease in superoxide dismutase activity in CSF regarding values obtained in control group (p < 0.05). The positive correlations regarding clinical score were obtained for all tested biomarkers (p < 0.01). Although the positive correlations were observed in MDA levels in plasma and CSF, for both study patients, and their radiological findings (p < 0.01), and a negative correlation in plasma SOD activity and CIS patients' radiological findings (p < 0.01), no other similar correlations were obtained. These findings might be useful in providing the earliest antioxidative treatment in neuroinflammation aimed to preserve total and CNS antioxidative capacity parallel with delaying irreversible, later neurological disabilities.

Biotransformation of nitric oxide in the cerebrospinal fluid of amyotrophic lateral sclerosis patients

Recent findings indicate that nitric oxide (NO*) over-production might be an important factor in the pathogenesis of sporadic amyotrophic lateral sclerosis (SALS). We measured significantly higher concentrations of uric acid and thiol group-containing molecules (R-SH groups) in the cerebrospinal fluid (CSF) from SALS patients compared to controls. The above factors, together with a slightly increased free iron concentration found in the CSF, favour conditions necessary for the formation of the dinitrosyl iron complex, capable of NO* bio-transformation. Thus, we performed ex vivo saturation of CSF (from both SALS patients and controls) with NO*. A decrease in the level of R-SH was found. This was more pronounced in the CSF from SALS patients. In the CSF from SALS patients the production of nitrite and hydroxylamine was greater than that observed in the CSF from controls. Moreover, we also found increased Cu,Zn-SOD activity in the CSF from SALS patients (when compared to control subjects) but no activity corresponding to Mn-SOD in any CSF samples. As Cu,Zn-SOD can react with nitroxyl forming NO*, the conditions for a closed, but continuous, loop of NO* biotransformation are present in the CSF of ALS patients.

Mitochondrial dysfunction in Parkinson's disease

Parkinson's disease (PD) is a progressive, neurodegenerative condition that has increasingly been linked with mitochondrial dysfunction and inhibition of the electron transport chain. This inhibition leads to the generation of reactive oxygen species and depletion of cellular energy levels, which can consequently cause cellular damage and death mediated by oxidative stress and excitotoxicity. A number of genes that have been shown to have links with inherited forms of PD encode mitochondrial proteins or proteins implicated in mitochondrial dysfunction, supporting the central involvement of mitochondria in PD. This involvement is corroborated by reports that environmental toxins that inhibit the mitochondrial respiratory chain have been shown to be associated with PD. This paper aims to illustrate the considerable body of evidence linking mitochondrial dysfunction with neuronal cell death in the substantia nigra pars compacta (SNpc) of PD patients and to highlight the important need for further research in this area.

Kinetics differ between copper-zinc and manganese superoxide dismutase activity with acute ischemic stroke

This study aimed to clarify the kinetics of copper-zinc (CuZn) and manganese (Mn) superoxide dismutase (SOD) activity in acute ischemic stroke victims. Using the nitrite method, we investigated sequential changes in CuZn and Mn SOD activity in the cerebrospinal fluid (CSF) of 8 patients with acute ischemic stroke. SOD activity in each patient was measured at 36 hours and 3, 7, 14, and 28 days after stroke. CuZn SOD activity in CSF peaked 3 days after stroke, with values gradually decreasing after 7 days. In contrast, Mn SOD activity remained significantly lower in the stroke group than in controls throughout the study. These findings may reflect differences between the 2 isoenzymes in terms of the distribution, role, and method of synthesis in brain tissue.

A common property of amyotrophic lateral sclerosis-associated variants: destabilization of the copper/zinc superoxide dismutase electrostatic loop

At least 119 mutations in the gene encoding copper/zinc superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis by an unidentified toxic gain of function. We compared the dynamic properties of 13 as-isolated, partially metallated, SOD1 variant enzymes using hydrogen-deuterium exchange. We identified a shared property of these familial amyotrophic lateral sclerosis-related SOD1 variants, namely structural and dynamic change affecting the electrostatic loop (loop VII) of SOD1. Furthermore, SOD1 variants that have severely compromised metal binding affinities demonstrated additional structural and dynamic changes to the zinc-binding loop (loop IV) of SOD1. Although the biological consequences of increased loop VII mobility are not fully understood, this common property is consistent with the hypotheses that SOD1 mutations exert toxicity via aggregation or aberrant association with other cellular constituents.

Proteomic identification of dopamine-conjugated proteins from isolated rat brain mitochondria and SH-SY5Y cells

Dopamine oxidation has been previously demonstrated to cause dysfunction in mitochondrial respiration and membrane permeability, possibly related to covalent modification of critical proteins by the reactive dopamine quinone. However, specific mitochondrial protein targets have not been identified. In this study, we utilized proteomic techniques to identify proteins directly conjugated with (14)C-dopamine from isolated rat brain mitochondria exposed to radiolabeled dopamine quinone (150 microM) and differentiated SH-SY5Y cells treated with (14)C-dopamine (150 microM). We observed a subset of rat brain mitochondrial proteins that were covalently modified by (14)C-dopamine, including chaperonin, ubiquinol-cytochrome c reductase core protein 1, glucose regulated protein 75/mitochondrial HSP70/mortalin, mitofilin, and mitochondrial creatine kinase. We also found the Parkinson's disease associated proteins ubiquitin carboxy-terminal hydrolase L1 and DJ-1 to be covalently modified by dopamine in both brain mitochondrial preparations and SH-SY5Y cells. The susceptibility of the identified proteins to covalent modification by dopamine may carry implications for their role in the vulnerability of dopaminergic neurons in Parkinson's disease pathogenesis.

Oxidative stress in perinatal asphyxia

Oxygen free radicals may cause tissue injury in perinatal asphyxia. We measured plasma and cerebrospinal fluid levels of malondialdehyde and plasma levels of glutathione peroxidase, catalase, and superoxide dismutase in 50 term newborns with perinatal asphyxia and eight newborns without asphyxia. Neonates with sepsis, major congenital malformations, and hemolytic disease were excluded. The levels of plasma and cerebrospinal fluid malondialdehyde, as well as of plasma glutathione peroxidase, catalase, and superoxide dismutase, were significantly higher in newborns with perinatal asphyxia, and demonstrated a progressive increase with greater severity of hypoxic ischemic encephalopathy. Higher levels of plasma and cerebrospinal fluid malondialdehyde and plasma catalase were documented in newborns who died from hypoxic ischemic encephalopathy, compared with those who survived, but no such difference was found in plasma levels of glutathione peroxidase and superoxide dismutase. The data of the present study suggest that, despite the increased activities of antioxidant enzymes in perinatal asphyxia, these neonates experience higher degrees of oxidative stress, as evidenced by increased levels of plasma and cerebrospinal fluid malondialdehyde. Hence, oxygen free radicals can be considered to play a significant role in the pathophysiology of perinatal asphyxia.

Reactive oxygen species plasmatic levels in ischemic stroke

Oxidative stress is probably one of the mechanisms involved in neuronal damage induced by ischemia-reperfusion, and the antioxidant activity of plasma may be an important factor providing protection from neurological damage caused by stroke-associated oxidative stress. The aim of this study was to investigate the status of oxidative stress, NO and ONOO(-) levels in patients with atherothrombotic and lacunar acute ischemic stroke and iNOS, eNOS and nitrotyrosine expression in the same patients. Plasma ONOO(-) levels were significantly higher in patients than in controls while NO decreases in patients in respect to controls. Densitometric analysis of bands indicated that iNOS and N-Tyr protein levels were significantly higher in patients in respect to controls. This study has highlighted a significant NO decrease in our patients compared with controls and this is most probably due to the increased expression of inducible NO synthase by the effect of thrombotic attack. In fact, the constitutive NO isoforms, which produce small amounts of NO, are beneficial, while activation of the inducible isoform of NO, which produces much more NO, causes injury, being its toxicity greatly enhanced by generation of peroxynitrite. The significant ONOO(-) increase observed in our patients, compared to controls, is most probably due to reaction of NO with O(2)(*-) . These findings suggest that free radical production and oxidative stress in ischemic stroke might have a major role in the pathogenesis of ischemic brain injury. Peroxynitrite might be the main marker of brain damage and neurological impairment in acute ischemic stroke.

Iron metabolism in Parkinsonian syndromes

Growing evidence suggests an involvement of iron in the pathophysiology of neurodegenerative diseases. Several of the diseases are associated with parkinsonian syndromes, induced by degeneration of basal ganglia regions that contain the highest amount of iron within the brain. The group of neurodegenerative disorders associated with parkinsonian syndromes with increased brain iron content can be devided into two groups: (1) parkinsonian syndromes associated with brain iron accumulation, including Parkinson's disease, diffuse Lewy body disease, parkinsonian type of multiple system atrophy, progressive supranuclear palsy, corticobasal ganglionic degeneration, and Westphal variant of Huntington's disease; and (2) monogenetically caused disturbances of brain iron metabolism associated with parkinsonian syndromes, including aceruloplasminemia, hereditary ferritinopathies affecting the basal ganglia, and panthotenate kinase associated neurodegeneration type 2. Although it is still a matter of debate whether iron accumulation is a primary cause or secondary event in the first group, there is no doubt that iron-induced oxidative stress contributes to neurodegeneration. Parallels concerning pathophysiological as well as clinical aspects can be drawn between disorders of both groups. Results from animal models and reduction of iron overload combined with at least partial relief of symptoms by application of iron chelators in patients of the second group give hope that targeting the iron overload might be one possibility to slow down the neurodegenerative cascade also in the first group of inevitably progressive neurodegenerative disorders.

Activities of endogenous antioxidant enzymes in the cerebrospinal fluid and the hippocampus after transient forebrain ischemia in rat

The activity of SOD and CAT was measured in controls and 5 h after 5, 10 and 15 min of ischemia, as well as 1 or 2 days after 10 min of ischemia in the hippocampus and in the CSF. A significant increase in total SOD activity 5 h after ischemia was caused mainly by increased CuZn-SOD activity. The highest values were measured 5 h after 5 min ischemia (by 160%) and smallest if 15 min (by 40%) of ischemia was used. In comparison to the hippocampus, the activity of SOD in CSF increased equally after all intervals of ischemia. Activities of total SOD and CuZn-SOD after 10 min of ischemia in the hippocampus were significantly increased only after 5 and 24 h of reperfusion but in CSF they were increased after all examined intervals of reperfusion. The activity of CAT was significantly increased in the hippocampus after 5 (by 260%), 10 and 15 min (by 100%) of ischemia. CAT activity in CSF was increased equally after all intervals of ischemia (by 200%). Ischemic attack causes a rapid response in hippocampal tissue as well as in the CSF, represented by an increase in the activity of endogenous antioxidant enzymes SOD and CAT.

Alterations in antioxidant enzyme activities in cerebrospinal fluid related with severity of hypoxic ischemic encephalopathy in newborns

BACKGROUND

The antioxidant status of the tissue affected by ischemia-reperfusion is of great importance for the primary endogenous defense against the free-radical-induced injury.

OBJECTIVE

In this study, we aimed to evaluate the relationship between the activities of antioxidant enzymes [superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT)] in cerebrospinal fluid (CSF) and severity of hypoxic-ischemic encephalopathy (HIE) in newborns.

METHODS

Thirty full-term asphyxiated infants (gestational age >37 weeks) and 11 full-term infants (none of whom showed any signs of asphyxia) were included in this study. Activities of SOD, GPX, and CAT in CSF were measured within the first 72 h of life in infants with HIE and controls.

RESULTS

Activity of SOD in CSF was significantly higher in infants with HIE compared with controls (p<0.05). GPX and CAT activities were higher in infants with HIE than they were in controls; however, the differences were not statistically significant (p > 0.05). The activities of GPX and CAT were significantly increased in severe HIE as compared with mild HIE and controls (p < 0.05).

CONCLUSION

Both the duration of the hypoxic-ischemic insult and the severity of HIE modulate elevations of enzymatic activity as an adaptive response to excessive free radical production in CSF in newborn infants with HIE. The activities of antioxidant enzyme alterations in CSF correspond highly to the severity of HIE, and these patterns may be useful for diagnostic and prognostic purposes.

Redox imbalance

Substantial evidence implies that redox imbalance attributable to an overproduction of reactive oxygen species or reactive nitrogen species that overwhelm the protective defense mechanism of cells contributes to all forms of Parkinson's disease. Factors such as dopamine, neuromelanin, and transition metals may, under certain circumstances, contribute to the formation of oxygen species such as H(2)O(2), superoxide radicals, and hydroxyl radicals and react with reactive nitrogen species such as nitric oxide or peroxinitrite. Mitochodrial dysfunction and excitotoxicity may be a cause and a result of oxidative stress. Consequences of this redox imbalance are lipid peroxidation, oxidation of proteins, DNA damage, and interference of reactive oxygen species with signal transduction pathways. These consequences become even more harmful when genetic variations impair the normal degradation of altered proteins. Therefore, therapeutic strategies must aim at reducing free-radical formation and scavenging free-radicals.

Oxidative injury to endothelial cells due to Epstein-Barr virus-induced autoantibodies against manganese superoxide dismutase

During the course of acute Epstein-Barr virus (EBV) infection, there is a rise of oxygen radical production. As a consequence, the production of the oxygen radical scavenger manganese superoxide dismutase (MnSOD) is increased. Patients with acute EBV infections regularly develop autoantibodies against MnSOD that are able to inhibit the enzyme activity in vitro. To elucidate the origin of the autoantibodies, the epitopes on MnSOD were determined. The entire sequence of MnSOD was synthesized as overlapping pentadecapeptides, which were scanned for their reactivity with sera of patients with acute EBV infections. Sera as well as affinity-purified anti-MnSOD antibodies reacted with the peptides p(no15) (amino acids 47-61) and p(no30) (amino acids 122-136) lying in crucial parts of the MnSOD tetramer. The two main epitopes p(no15) and p(no30) showed sequence homologies with EBV-encoded proteins. Reactivity of affinity-purified antibodies with a peptide of the homologous BGLF4 points to a molecular mimicry causing the occurrence of anti-MnSOD antibodies. Anti-MnSOD antibodies were able to block the protective effects of MnSOD in a model for oxidative damage produced by xanthine/xanthine oxidase in EAhy926 endothelial cells. Thus, these autoantibodies may contribute in vivo to the clinical symptoms by accumulation of toxic oxygen radicals.

Oxidative stress in Parkinson's disease

Oxidative stress contributes to the cascade leading to dopamine cell degeneration in Parkinson's disease (PD). However, oxidative stress is intimately linked to other components of the degenerative process, such as mitochondrial dysfunction, excitotoxicity, nitric oxide toxicity and inflammation. It is therefore difficult to determine whether oxidative stress leads to, or is a consequence of, these events. Oxidative damage to lipids, proteins, and DNA occurs in PD, and toxic products of oxidative damage, such as 4-hydroxynonenal (HNE), can react with proteins to impair cell viability. There is convincing evidence for the involvement of nitric oxide that reacts with superoxide to produce peroxynitrite and ultimately hydroxyl radical production. Recently, altered ubiquitination and degradation of proteins have been implicated as key to dopaminergic cell death in PD. Oxidative stress can impair these processes directly, and products of oxidative damage, such as HNE, can damage the 26S proteasome. Furthermore, impairment of proteasomal function leads to free radical generation and oxidative stress. Oxidative stress occurs in idiopathic PD and products of oxidative damage interfere with cellular function, but these form only part of a cascade, and it is not possible to separate them from other events involved in dopaminergic cell death.

6-Hydroxydopamine-lesioning of the nigrostriatal pathway in rats alters basal ganglia mRNA for copper, zinc- and manganese-superoxide dismutase, but not glutathione peroxidase

The effects of nigrostriatal pathway destruction on the mRNA levels of copper, zinc-dependent superoxide dismutase (Cu,Zn-SOD), manganese-dependent superoxide dismutase (Mn-SOD), and glutathione peroxidase in basal ganglia of adult rat were investigated using in situ hybridization histochemistry and oligodeoxynucleotide (single-stranded complementary DNA) probes. The 6-hydroxydopamine (6-OHDA)-induced destruction of the nigrostriatal pathway resulted in contralateral rotation to apomorphine and a marked loss of specific [(3)H]mazindol binding in the striatum (93%; P<0.05) and of tyrosine hydroxylase mRNA in substantia nigra pars compacta (SC) (93%; P<0.05) compared with control rats. Levels of Cu,Zn-SOD mRNA were decreased in the striatum, globus pallidus, and SC on the lesioned side of 6-OHDA-lesioned rats compared with sham-lesioned rats (P<0.05). Levels of Mn-SOD mRNA were increased in the nucleus accumbens (P<0.05), but decreased in the SC (P<0.05) on the lesioned side of 6-OHDA-treated rats compared with sham-lesioned rats. Lesioning with 6-OHDA had no effect on glutathione peroxidase mRNA levels in any region of basal ganglia examined. The significant changes in Cu,Zn-SOD and Mn-SOD mRNA indicate that SOD is primarily expressed by dopaminergic neurons of the nigrostriatal pathway, and that the Mn-SOD gene appears to be inducible in rat basal ganglia in response to both physical and chemical damage 5 weeks after 6-OHDA-lesioning. These findings may clarify the status of antioxidant enzymes, particularly Mn-SOD, in patients with Parkinson's disease and their relevance to disease pathogenesis.

Tissue distribution and neuroprotective effects of citrus flavonoid tangeretin in a rat model of Parkinson's disease

Neuroprotective effects of a natural antioxidant tangeretin, a citrus flavonoid, were elucidated in the 6-hydroxydopamine (6-OHDA) lesion rat model of Parkinson's disease (PD), after bioavailability studies. Following the chronic oral administration (10 mg/kg/day for 28 days), significant levels of tangeretin were detected in the hypothalamus, striatum and hippocampus (3.88, 2.36 and 2.00 ng/mg, respectively). The levels in the liver and plasma were 0.59 ng/mg and 0.11 ng/ml respectively. Unilateral infusion of the dopaminergic neurotoxin, 6-hydroxydopamine (6-OHDA; 8 microg), onto medial forebrain bundle significantly reduced the number of tyrosine hydroxylase positive (TH+) cells in the substantia nigra and decreased striatal dopamine content in the vehicle treated rats. Sub-chronic treatment of the rats with high doses of tangeretin (20 mg/kg/day for 4 days; p.o.) before 6-OHDA lesioning markedly reduced the loss of both TH+ cells and striatal dopamine content. These studies, for the first time, give evidence that tangeretin crosses the blood-brain barrier. The significant protection of striato-nigral integrity and functionality by tangeretin suggests its potential use as a neuroprotective agent.

Superoxide dismutase activity and zinc and copper concentrations in Parkinson's disease

Although several hypotheses are currently being investigated the cause of Parkinson's disease (PD) is still unknown. The aim of this study was to determine red cell copper/zinc-superoxide dismutase (Cu/Zn-SOD) activity and copper and zinc concentrations both in plasma and in red cell in PD. In this preliminary assay, 30 patients with PD the mean age of 64 were studied. Additionally, a second group of older individuals without PD mean age of 61, were recruited to the study. The patient group was compared with the other group according to their red cell Cu/Zn-SOD activities, and plasma and red cell copper, zinc concentrations. Red cell Cu/Zn-SOD activity was measured spectrophotometrically while plasma and red cell copper, zinc concentrations were determined by atomic absorption spectrophotometer. The results were analysed by 'Student t-test' statistically. The results showed that red cell Cu/Zn-SOD activities and red cell copper and zinc and also plasma copper concentrations of the PD patients increased compared to older individuals without PD. These findings suggested that possibility of oxidative stress in PD was reflected on the blood including the red cell and plasma parameters.

Pathogenesis and preclinical course of Parkinson's disease

Idiopathic parkinsonism (IP) is defined by its classic symptomology, its responsiveness to therapies which elevate dopamine levels, and by the failure to identify a specific etiological factor. The progressive and irreversible degeneration of dopaminergic neurons projecting from the substantia nigra pars compacta (SNc) to the striatum and the presence of SNc Lewy bodies are regarded as the essential pathological bases of IP, but neither the initiator(s) nor the nature of the degeneration have been determined, nor its relationship with degenerative changes in other parts of the IP brain. This paper discusses the various hypotheses that have been proposed to explain these phenomena, arguing that IP be regarded as a multisystem disorder, both at the level of individual neurons and at the whole brain level. It is probable that IP is the result of a multifactorial process, and that a cascade of interacting and overlapping biochemical mechanisms determine the course of the disease.

Changes in anti-oxidant enzymes and lipid peroxidation in hyaline membrane disease

This study was conducted to elucidate the changes in key antioxidant enzymes e.g. Superoxide dismutase (SOD), Catalase and Glutathione peroxidase (GPx) along with lipid peroxidation (LPO) in preterm newborns having hyaline membrane disease (HMD) and thus to find out role of free radicals mediated injury in this disease. Twenty one preterm appropriate for gestational age newborns were included in the study. Eleven of them had hyaline membrane disease and ten were controls without any disease. Status of superoxide dismutase, glutathione peroxidase and catalase, the three main antioxidant enzymes and lipid peroxidation was monitored at 12-24 hours of age. SOD and catalase were found significantly elevated in cases having hyaline membrane disease along with significantly more lipid peroxidation. It is evident that free radicals result in the induction of the antioxidant enzymes; however, the elevated enzymes are unable to counteract the high concentration of the free radicals which are being produced in the diseased cases and leads to increase in lipid peroxidation in hyaline membrane disease. It is concluded that free radicals play a significant role in hyaline membrane disease and the preterm newborns have ability to induce antioxidant enzymes in response to oxidative stress.

Aging and superoxide dismutase activity in cerebrospinal fluid

We investigated superoxide dismutase (SOD) activity in human cerebrospinal fluid (CSF) as an index of the aging process in the central nervous system (CNS). The subjects were 61 individuals aged 21-77 years, comprising 24 men and 37 women without organic disorders of the nervous system. SOD activity in CSF was measured by the nitrite method modified by Oyanagui. The results showed that SOD activity in CSF gradually increased with age and that the values of SOD activity after the fifth decade were significantly higher than those in the third and fourth decades. It might suggest that the productivity of SOD in the CNS gradually increased with age due to stimulation of various types of oxidative stress which accumulated in vivo especially after the fifth decade.

Decreased thermal stability of red blood cell glu100-->gly superoxide dismutase from a family with amyotrophic lateral sclerosis

Familial amyotrophic lateral sclerosis is a degenerative motor neuron disease associated in some cases with the presence of a mutant form of Cu/Zn superoxide dismutase. We have studied the stability of the gly100-->glu mutant in extracts of red cells obtained from members of a family with a history of the disease. Extracts containing the mutant had an average 68% of normal superoxide dismutase activity. On heating at 65 degrees C, these extracts lost activity at twice the rate of extracts containing only the normal enzyme. Decreased heat stability was also evident on native polyacrylamide gel electrophoresis with activity staining. This showed selective loss of first the mutant homodimer and then the heterodimer of the enzyme. Decreased stability intracellularly could be a factor in motor neuron degeneration.

Elevated cerebrospinal fluid levels of manganese superoxide dismutase in bacterial meningitis

We examined the mechanism of increase of manganese superoxide dismutase (Mn SOD) in the cerebrospinal fluid (CSF) in bacterial meningitis (BM). The elevated levels of Mn SOD in the CSF in BM, measured with an enzyme immunoassay method, were more prominent than those in aseptic meningitis (AM) and encephalitis (EN). In AM and EN Mn SOD levels well correlated with levels of neuron-specific enolase and S-100b protein, which are markers of damages to nervous tissues, but did not with any of them in BM. CSF concentrations of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha) were higher in BM than in AM and EN. From the serial measurements in BM, the peak values of these cytokines chronologically preceded or corresponded to those of Mn SOD. Immunohistochemically, a large number of the glial cells were stained for Mn SOD in the cerebral cortex from a patient with BM. By contrast, in the normal cerebral cortex, the glial cells were negative for Mn SOD staining. These results suggest that the marked increase of Mn SOD in the CSF in BM may be related to the increase of such cytokines as TNF-alpha and IL-1 alpha and that these cytokines may play a role in the induction of Mn SOD in nervous tissues.