Oxidant and antioxidant activities in childhood meningitis

Urinary metabolic characterization of advanced tuberculous meningitis cases in a South African paediatric population

Tuberculous meningitis (TBM) is a severe form of tuberculosis with high neuro-morbidity and mortality, especially among the paediatric population (aged ≤12 years). Little is known of the associated metabolic changes. This study aimed to identify characteristic metabolic markers that differentiate severe cases of paediatric TBM from controls, through non-invasive urine collection. Urine samples selected for this study were from two paediatric groups. Group 1: controls (n = 44): children without meningitis, no neurological symptoms and from the same geographical region as group 2. Group 2: TBM cases (n = 13): collected from paediatric patients that were admitted to Tygerberg Hospital in South Africa on the suspicion of TBM, mostly severely ill; with a later confirmation of TBM. Untargeted 1H NMR-based metabolomics data of urine were generated, followed by statistical analyses via MetaboAnalyst (v5.0), and the identification of important metabolites. Twenty nine urinary metabolites were identified as characteristic of advanced TBM and categorized in terms of six dysregulated metabolic pathways: 1) upregulated tryptophan catabolism linked to an altered vitamin B metabolism; 2) perturbation of amino acid metabolism; 3) increased energy production-metabolic burst; 4) disrupted gut microbiota metabolism; 5) ketoacidosis; 6) increased nitrogen excretion. We also provide original biological insights into this biosignature of urinary metabolites that can be used to characterize paediatric TBM patients in a South African cohort.

High Concentration of Protein Oxidation Biomarker O-Tyr/Phe Predicts Better Outcome in Childhood Bacterial Meningitis

Neuronal damage in bacterial meningitis (BM) partly stems from the host´s inflammatory response and induced oxidative stress (OS). We studied the association of cerebrospinal fluid (CSF) biomarkers indicating oxidative damage to proteins with course of illness and outcome in childhood BM in Angola. Ortho-tyrosine/phenylalanine (o-Tyr/Phe), 3-chlorotyrosine/para-tyrosine (3Cl-Tyr/p-Tyr), and 3-nitrotyrosine/para-tyrosine (3NO2-Tyr/p-Tyr) concentration ratios were measured in 79 BM admission CSF samples, employing liquid chromatography coupled to tandem mass spectrometry. Besides death, disease outcomes were registered on Day 7 of treatment and one month after discharge (control visit). The outcome was graded according to the modified Glasgow Outcome Scale (GOS), which considers neurological and audiological sequelae. Children with a o-Tyr/Phe ratio below the median were more likely to present focal convulsions and secondary fever during recovery and suboptimal outcome (GOS < 5) on Day 7 and at control visit (odds ratio (OR) 2.85; 95% CI 1.14–7.14 and OR 5.23; 95% CI 1.66–16.52, respectively). Their most common sequela was ataxia on Day 7 and at control visit (OR 8.55; 95% CI 2.27–32.22 and OR 5.83; 95% CI 1.12–30.4, respectively). The association of a higher admission CSF o-Tyr/Phe ratio with a better course and outcome for pediatric BM points to a beneficial effect of OS.

Protein Oxidation Biomarkers and Myeloperoxidase Activation in Cerebrospinal Fluid in Childhood Bacterial Meningitis

The immunological response in bacterial meningitis (BM) causes the formation of reactive oxygen and nitrogen species (ROS, RNS) and activates myeloperoxidase (MPO), an inflammatory enzyme. Thus, structural oxidative and nitrosative damage to proteins and DNA occurs. We aimed to asses these events in the cerebrospinal fluid (CSF) of pediatric BM patients. Phenylalanine (Phe), para-tyrosine (p-Tyr), nucleoside 2'-deoxiguanosine (2dG), and biomarkers of ROS/RNS-induced protein and DNA oxidation: ortho-tyrosine (o-Tyr), 3-chlorotyrosine (3Cl-Tyr), 3-nitrotyrosine (3NO₂-Tyr) and 8-oxo-2'-deoxyguanosine (8OHdG), concentrations were measured by liquid chromatography coupled to tandem mass spectrometry in the initial CSF of 79 children with BM and 10 without BM. All biomarkers, normalized with their corresponding precursors, showed higher median concentrations (p < 0.0001) in BM compared with controls, except 8OHdG/2dG. The ratios o-Tyr/Phe, 3Cl-Tyr/p-Tyr and 3NO₂-Tyr/p-Tyr were 570, 20 and 4.5 times as high, respectively. A significantly higher 3Cl-Tyr/p-Tyr ratio was found in BM caused by Streptococcus pneumoniae, than by Haemophilus influenzae type b, or Neisseria meningitidis (p = 0.002 for both). In conclusion, biomarkers indicating oxidative damage to proteins distinguished BM patients from non-BM, most clearly the o-Tyr/Phe ratio. The high 3Cl-Tyr/p-Tyr ratio in pneumococcal meningitis suggests robust inflammation because 3Cl-Tyr is a marker of MPO activation and, indirectly, of inflammation.

Cerebrospinal Fluid Amino Acid Profiling of Pediatric Cases with Tuberculous Meningitis

Background: In Africa, tuberculosis is generally regarded as persisting as one of the most devastating infectious diseases. The pediatric population is particularly vulnerable, with infection of the brain in the form of tuberculous meningitis (TBM) being the most severe manifestation. TBM is often difficult to diagnose in its early stages because of its non-specific clinical presentation. Of particular concern is that late diagnosis, and subsequent delayed treatment, leads to high risk of long-term neurological sequelae, and even death. Using advanced technology and scientific expertise, we are intent on further describing the biochemistry behind this devastating neuroinflammatory disease, with the goal of improving upon its early diagnosis.

Method: We used the highly sensitive analytical platform of gas chromatography-mass spectrometry (GC-MS) to analyze amino acid profiles of cerebrospinal fluid (CSF) collected from a cohort of 33 South African pediatric TBM cases, compared to 34 controls.

Results: Through the use of a stringent quality assurance procedure and various statistical techniques, we were able to confidently identify five amino acids as being significantly elevated in TBM cases, namely, alanine, asparagine, glycine, lysine, and proline. We found also in an earlier untargeted metabolomics investigation that alanine can be attributed to increased CSF lactate levels, and lysine as a marker of lipid peroxidation. Alanine, like glycine, is an inhibitory neurotransmitter in the brain. Asparagine, as with proline, is linked to the glutamate-glutamine cycle. Asparagine is associated with the removal of increased nitrites in the brain, whereas elevated proline coincides with the classic biochemical marker of increased CSF protein in TBM. All five discriminatory amino acids are linked to ammonia due to increased nitrites in TBM.

Conclusion: A large amount of untapped biochemical information is present in CSF of TBM cases, of which amino acid profiling through GC-MS has potential in aiding in earlier diagnosis, and hence crucial earlier treatment.

Temporal changes of oxidative stress markers in Escherichia coli K1-induced experimental meningitis in a neonatal rat model

Despite advances in antimicrobial therapy and advanced critical care neonatal bacterial meningitis has a mortality rate of over 10% and induces neurological sequelae in 20-50% of cases. Escherichia coli K1 (E. coli K1) is the most common gram-negative organism causing neonatal meningitis and is the second most common cause behind group B streptococcus. We previously reported that an E. coli K1 experimental meningitis infection in neonatal rats resulted in habituation and aversive memory impairment and a significant increase in cytokine levels in adulthood. In this present study, we investigated the oxidative stress profile including malondialdehyde (MDA) levels, carbonyl protein formation, myeloperoxidase activity (MPO) activity, superoxide dismutase (SOD) activity and catalase (CAT) activity 6, 12, 24, 48, 72 and 96h after E. coli K1 experimental meningitis infection. In addition, sulfhydryl groups, nitrite and nitrate levels and activity of the mitochondrial respiratory chain enzymes were also measured in the frontal cortex and hippocampus of neonatal rats. The results from this study demonstrated a significant increase in MDA, protein carbonyls and MPO activity and a simultaneous decrease in SOD activity in the hippocampus of the neonatal meningitis survivors but the same was not observed in frontal cortex. In addition, we also observed a significant increase in complex IV activity in the hippocampus and frontal cortex of meningitis survivor rats. Thus, the results from this study reaffirmed the possible role of oxidative stress, nitric oxide and its related compounds in the complex pathophysiology of E. coli K1-induced bacterial meningitis.

Acrolein enhances epigenetic modifications, FasL expression and hepatocyte toxicity induced by anti-HIV drug Zidovudine

Zidovudine (AZT) remains the mainstay of antiretroviral therapy against HIV in resource-poor countries; however, its use is frequently associated with hepatotoxicity. Not all HIV patients on AZT develop hepatotoxicity, and the determining factors are unclear. Alcohol consumption and cigarette smoking are known risk factors for HIV hepatotoxicity, and both are significant sources of acrolein, a highly reactive and toxic aldehyde. This study examines the potential hepatotoxic interactions between acrolein and AZT. Our data demonstrate that acrolein markedly enhanced AZT-induced transcriptionally permissive histone modifications (H3K9Ac and H3K9Me3) allowing the recruitment of transcription factor NF-kB and RNA polymerase II at the FasL gene promoter, resulting in FasL upregulation and apoptosis in hepatocytes. Notably, the acrolein scavenger, hydralazine prevented these promoter-associated epigenetic changes and inhibited FasL upregulation and apoptosis induced by the combination of AZT and acrolein, as well as AZT alone. Our data strongly suggest that acrolein enhancement of promoter histone modifications and FasL upregulation are major pathogenic mechanisms driving AZT-induced hepatotoxicity. Moreover, these data also indicate the therapeutic potential of hydralazine in mitigating AZT hepatotoxicity.

A hypothetical astrocyte-microglia lactate shuttle derived from a 1H NMR metabolomics analysis of cerebrospinal fluid from a cohort of South African children with tuberculous meningitis

Tuberculosis meningitis (TBM) is the most severe form of extra-pulmonary tuberculosis and is particularly intense in small children; there is no universally accepted algorithm for the diagnosis and substantiation of TB infection, which can lead to delayed intervention, a high risk factor for morbidity and mortality. In this study a proton magnetic resonance (¹H NMR)-based metabolomics analysis and several chemometric methods were applied to data generated from lumber cerebrospinal fluid (CSF) samples from three experimental groups: (1) South African infants and children with confirmed TBM, (2) non-meningitis South African infants and children as controls, and (3) neurological controls from the Netherlands. A total of 16 NMR-derived CSF metabolites were identified, which clearly differentiated between the controls and TBM cases under investigation. The defining metabolites were the combination of perturbed glucose and highly elevated lactate, common to some other neurological disorders. The remaining 14 metabolites of the host's response to TBM were likewise mainly energy-associated indicators. We subsequently generated a hypothesis expressed as an "astrocyte-microglia lactate shuttle" (AMLS) based on the host's response, which emerged from the NMR-metabolomics information. Activation of microglia, as implied by the AMLS hypothesis, does not, however, present a uniform process and involves intricate interactions and feedback loops between the microglia, astrocytes and neurons that hamper attempts to construct basic and linear cascades of cause and effect; TBM involves a complex integration of the responses from the various cell types present within the CNS, with microglia and the astrocytes as main players.

The pharmacological features of bilirubin: the question of the century

This review looks at the toxicity and metabolism of bilirubin in terms of its pharmacological potential. Its role has gained importance as more research has revealed the functional significance and interrelationship between the gasotransmitters nitric oxide and carbon monoxide. The biological actions of bilirubin have mostly been characterized in the high micromolar range where toxic effects occur. However, it could also prove to be an important cytoprotector for brain tissue, which is inherently less equipped for antioxidant defense. Plasma bilirubin levels negatively correlate to a number of disease states. Higher levels of bilirubin that are still within the normal range provide a protective effect to the body. The effects on various disorders could be tested using controlled pharmacological upregulation of the molecule with animal models. At nanomolar concentrations, considerable benefits have been obtained when the molecule was delivered pharmacologically under in vitro or in vivo test conditions, particularly in neurodegenerative disorders and after tissue or organ transplantation. The induction of heme oxygenase-1 (HMOX-1) via the activation of nuclear factor erythroid 2-related factor or the use of bile pigments in the harvesting of diseased tissue are novel applications, and like every new therapy, should be used with caution. HMOX-1 is tissue specific, and in exceptional states, such as schizophrenia and specific types of renal disorder, the same therapy may have disastrous effects.

Pathophysiology of neonatal acute bacterial meningitis

Neonatal meningitis is a severe acute infectious disease of the central nervous system and an important cause of morbidity and mortality worldwide. The inflammatory reaction involves the meninges, the subarachnoid space and the brain parenchymal vessels and contributes to neuronal injury. Neonatal meningitis leads to deafness, blindness, cerebral palsy, seizures, hydrocephalus or cognitive impairment in approximately 25-50 % of survivors. Bacterial pathogens can reach the blood-brain barrier and be recognized by antigen-presenting cells through the binding of Toll-like receptors. They induce the activation of NFκB or mitogen-activated protein kinase pathways and subsequently upregulate leukocyte populations and express numerous proteins involved in inflammation and the immune response. Many brain cells can produce cytokines, chemokines and other pro-inflammatory molecules in response to bacterial stimuli, and polymorphonuclear leukocytes are attracted, activated and released in large amounts of superoxide anion and nitric oxide, leading to peroxynitrite formation and generating oxidative stress. This cascade leads to lipid peroxidation, mitochondrial damage and breakdown of the blood-brain barrier, thus contributing to cell injury during neonatal meningitis. This review summarizes information on the pathophysiology and adjuvant treatment of acute bacterial meningitis in neonates.

Oxidative stress in children with bacterial meningitis

Bacterial meningitis is a common cause of morbidity and mortality in children. The oxidative stress in bacterial meningitis is barely determined. Forty children with bacterial meningitis were studied for their oxidants and antioxidants status in serum and cerebrospinal fluid. Fever (95%) was commonest presentation followed by seizure and vomiting. Neck rigidity and Kernig's sign were present in 37.5% and 27.5% cases, respectively. Plasma and cerebrospinal fluid malondialdehyde, protein carbonyl and nitrite levels were significantly raised in cases (p < 0.001). Plasma and cerebrospinal fluid ascorbic acid, glutathione and superoxide dismutase levels were significantly decreased in children with septic meningitis (p < 0.001). Significantly elevated malondialdehyde, nitrite and protein carbonyl levels reflect increased oxidative stress, whereas decreased concentrations of glutathione, ascorbic acid and superoxide dismutase indicates utilization of the antioxidants in septic meningitis. Thus, changes in oxidants and antioxidants observed suggest production of reactive oxygen species and their possible role in pathogenesis of septic meningitis.

Oxidative stress in children with neurocysticercosis

BACKGROUND

Free radicals can cause neuronal injury and play an important role in pathogenesis of neurocysticercosis. This study was done to evaluate oxidative stress (antioxidants and oxidants) in cerebrospinal fluid (CSF) of children with neurocysticercosis and to observe their correlation with the type of seizure and outcome.

METHODS

Forty consecutive confirmed cases of neurocysticercosis were evaluated for their markers of reactive oxygen species, that is, oxidants (malondialdehyde, protein carbonyl and nitrite) and antioxidant (superoxide dismutase, glutathione peroxidase, ceruloplasmin, ascorbic acid, copper and zinc) concentrations in CSF. An equal number of children, age and sex matched with an idiopathic generalized tonic-clonic seizure, were studied as controls.

RESULTS

Generalized tonic-clonic seizure (65%) was the most common presentation, and a single ring-enhancing lesion in the parietal lobe was the most common finding in cranial imaging. Oxidants such as malondialdehyde, protein carbonyl and nitrite in CSF were significantly elevated (P < 0.001), whereas antioxidants such as superoxide dismutase, glutathione peroxidase, ceruloplasmin, ascorbic acid, copper and zinc levels were significantly lower (P < 0.001) in children with neurocysticercosis than in controls. There were insignificant differences in oxidant and antioxidant value in CSF in relation to the type of seizure, number and location of lesion in cerebral cortex and antiepileptic therapy.

CONCLUSION

The significantly elevated malondialdehyde, nitrite and protein carbonyl values reflect increased oxidative stress, whereas decreased concentrations of glutathione peroxidase, ascorbic acid, zinc, copper, ceruloplasmin and superoxide dismutase point toward utilization of the antioxidants in neurocysticercosis. The observed changes in oxidants and antioxidants suggest the production of reactive oxygen species such as superoxide, hydrogen peroxides and hydroxyl radicals and their possible role in pathogenesis of neurocysticercosis.

Acrolein cytotoxicity in hepatocytes involves endoplasmic reticulum stress, mitochondrial dysfunction and oxidative stress

Acrolein is a common environmental, food and water pollutant and a major component of cigarette smoke. Also, it is produced endogenously via lipid peroxidation and cellular metabolism of certain amino acids and drugs. Acrolein is cytotoxic to many cell types including hepatocytes; however the mechanisms are not fully understood. We examined the molecular mechanisms underlying acrolein hepatotoxicity in primary human hepatocytes and hepatoma cells. Acrolein, at pathophysiological concentrations, caused a dose-dependent loss of viability of hepatocytes. The death was apoptotic at moderate and necrotic at high concentrations of acrolein. Acrolein exposure rapidly and dramatically decreased intracellular glutathione and overall antioxidant capacity, and activated the stress-signaling MAP-kinases JNK, p42/44 and p38. Our data demonstrate for the first time in human hepatocytes, that acrolein triggered endoplasmic reticulum (ER) stress and activated eIF2α, ATF-3 and -4, and Gadd153/CHOP, resulting in cell death. Notably, the protective/adaptive component of ER stress was not activated, and acrolein failed to up-regulate the protective ER-chaperones, GRP78 and GRP94. Additionally, exposure to acrolein disrupted mitochondrial integrity/function, and led to the release of pro-apoptotic proteins and ATP depletion. Acrolein-induced cell death was attenuated by N-acetyl cysteine, phenyl-butyric acid, and caspase and JNK inhibitors. Our data demonstrate that exposure to acrolein induces a variety of stress responses in hepatocytes, including GSH depletion, oxidative stress, mitochondrial dysfunction and ER stress (without ER-protective responses) which together contribute to acrolein toxicity. Our study defines basic mechanisms underlying liver injury caused by reactive aldehyde pollutants such as acrolein.

Prognostic significance of serum antioxidant parameters in immunocompetent patients with cryptococcal meningitis

The purpose of this investigation was to determine whether endogenous antioxidants were prognostic factors in immunocompetent patients with cryptococcal meningitis (CM). The clinical features, alterations of serum albumin, bilirubin, and uric acid (UA) levels before and after six weeks of treatment in 94 immunocompetent patients with CM from January 2000 to December 2010 were retrospectively analyzed. The patients with CM had lower serum albumin and UA levels and higher bilirubin levels before treatment. After six weeks of treatment, the serum bilirubin levels decreased significantly and the serum UA levels increased significantly in 'cured/improved' patients. The serum UA level was negatively correlated with log cerebrospinal fluid (CSF) cryptococcal count and positively correlated with the CSF glucose level. A significantly lower level of serum UA was associated with high CSF open pressure, hydrocephalus, brain lesions, and consciousness disturbance. Moreover, the good outcome was 7.779 times more likely to occur in patients with an increase in the serum UA level ≥38.8% after six weeks of treatment. A logistic regression analysis also confirmed that an increase in the serum UA level ≥38.8% after six weeks of treatment was an independent good outcome predictor. Though there were abnormal conditions of serum antioxidants, the variation in the UA level could serve as a potential indicator of therapeutic efficacy in immunocompetent patients with CM.

Oxidative stress and myeloperoxidase activity during bacterial meningitis: effects of febrile episodes and the BBB permeability

OBJECTIVE

To investigate participation of extracellular myeloperoxidase (MPO) in oxidative stress during different courses of the bacterial meningitis (BM).

MATERIALS AND METHODS

We sequentially assessed WBC count, blood-brain barrier (BBB) permeability, serum and cerebrospinal fluid (CSF) lipid peroxidation (LPO), MPO and antioxidative activity (AOA) in proven pediatric BM.

RESULTS

BM patients exhibited increased systemic and local LPO and MPO, and reduced AOA, which was exaggerated in the febrile episodes. Serum MPO and LPO products were related to the BBB permeability at the baseline. CSF hydroperoxide level was influenced by the BBB permeability, CSF albumin concentration, and serum hydroperoxide (r=0.502; p<0.001, and r=0.611; p<0.001, and r=0.358; p<0.001, respectively). CSF hydroperoxide and MPO correlated in complicated cases during the study.

CONCLUSIONS

These results suggest that CSF LPO and MPO were closely related in BM, had different courses if febrile episodes had occurred, but were partly influenced by the BBB permeability.

Brief Clinical Report: EVALUATION OF ANTIOXIDANT STATUS IN CHILDREN WITH ACUTE BACTERIAL MENINGITIS AND ENCEPHALITIS

Antioxidant status was investigated in children with acute bacterial meningitis and encephalitis to investigate the possible role of free radicals in children with meningitis and encephalitis. Our study included 16 children with acute bacterial meningitis, 13 with encephalitis, and 17 control subjects. Serum ceruloplasmin, uric acid, albumin, bilirubin superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) levels were studied in all subjects within 6 h of admission. There was a statistically significant difference between the groups for all parameters except for serum uric acid. All antioxidant activities except for albumin level were increased in the study groups. Albumin level was higher in the control group than those of meningitis and encephalitis groups. When the values of meningitis and encephalitis were compared, there was a statistically significant difference between the groups for serum SOD, GPx, ceruloplasmin, and albumin. In conclusion, our study showed that serum SOD, GPx, catalase, and ceruloplasmin were higher in children with acute bacterial meningitis and serum SOD, GPx, catalase, ceruloplasmin, and total bilirubin levels were increased in children with encephalitis. These findings suggest that antioxidant status was almost similar in both acute bacterial meningitis and encephalitis conditions in childhood.

Oxidative stress in cerebrospinal fluid of patients with aseptic and bacterial meningitis

This study aimed to determine whether patients with aseptic and bacterial meningitis presented alterations in oxidative stress parameters of cerebrospinal fluid (CSF). A total of 30 patients were used in the research. The CSF oxidative stress status has been evaluated through many parameters, such as lipid peroxidation through thiobarbituric acid reactive substances (TBARS) and antioxidant defense systems such as superoxide dismutase (SOD), glutathione S-transferase (GST), reduced glutathione (GSH) and ascorbic acid. TBARS levels, SOD and GST activity increase in aseptic meningitis and in bacterial meningitis. The ascorbic acid concentration increased significantly in patients with both meningitis types. The reduced glutathione levels were reduced in CSF of patients with aseptic and bacterial meningitis. In present study we may conclude that oxidative stress contributes at least in part to the severe neurological dysfunction found in meningitis.

Roles of oxidative stress in xeroderma pigmentosum

Tissue damage caused by oxidative stress has been implicated in aging, carcinogenesis, atherosclerosis and neurodegeneration. In xeroderma pigmentosum (XP) and Cockayne syndrome (CS), oxidative stress is associated with promoted occurrence of skin cancers and progressive neurodegeneration, because decreased DNA repair and persistent DNA damage can result in augmented oxidative nucleotide damage. Oxidative nucleotide damage has been investigated mainly in isolated human skin and blood cells or their cell lines, in which CS cells may be more sensitive to oxidative DNA lesions than XP cells. However, cells from patients with XP group A (XPA) show defective repair of 8, 5'-(S)-cyclo-2'-deoxyadenosine, a free radical-induced endogenous DNA lesion and antioxidant system seems to be disturbed variously in cells from XP patients. We have neuropathologically investigated the involvement of oxidative stress in the brains of XPA and CS autopsy cases and clarified the enhanced lipid peroxidation and protein glycation in the pallidal and cerebellar degeneration. Also, oxidative nucleotide damage with reduced expression of superoxide dismutases has been identified in the basal ganglia lesions, lending further weight involvement of oxidative stress in neurodegeneration in XPA patients. Additionally, we are developing ELISA analysis of oxidative stress markers in the urine and cerebrospinal fluid from XP patients, which will aid with further data on oxidative stress in pathogenesis of XP.

Cerebrospinal fluid Diacron-Reactive Oxygen Metabolite levels in pediatric patients with central nervous system diseases

This study assessed the validity of cerebrospinal fluid oxidative status of pediatric patients with central nervous system diseases, using the Diacron-Reactive Oxygen Metabolites test (d-Roms; Diacron International s.r.l.; Grosseto, Italy). Eighty-seven pediatric patients (8 with bacterial meningitis, 18 with aseptic meningitis, 23 with febrile seizures, 6 with rotavirus gastroenteritis-induced convulsions, 16 with epilepsy, 2 with adrenoleukodystrophy, 2 with multiple sclerosis, and 12 control subjects) were enrolled. An analysis of the infection-associated group (bacterial meningitis, aseptic meningitis, febrile seizures, and rotavirus gastroenteritis-induced convulsions) indicated that cerebrospinal fluid Diacron-Reactive Oxygen Metabolite levels in the bacterial meningitis group were significantly higher than in other infection-associated groups. In the bacterial meningitis group, the cerebrospinal fluid Diacron-Reactive Oxygen Metabolite levels obtained after improvement were significantly decreased compared with pre-improvement values. In the noninfection-associated group (epilepsy, adrenoleukodystrophy, and multiple sclerosis), the cerebrospinal fluid Diacron-Reactive Oxygen Metabolite levels in symptomatic epilepsy patients were higher than in cryptogenic epilepsy patients and control subjects, but not significantly. Progressive patients with adrenoleukodystrophy or multiple sclerosis demonstrated high Diacron-Reactive Oxygen Metabolite levels compared with another early-stage adrenoleukodystrophy patient. Oxidative stress may be associated with the pathogenesis of various pediatric central nervous system diseases. Cerebrospinal fluid Diacron-Reactive Oxygen Metabolite levels may correlate with clinical status in these diseases.

Oxidant and antioxidant parameters in the treatment of meningitis

The aim of this study was to assess the effects of meningitis treatment on the serum and cerebrospinal-fluid oxidant and antioxidant status in children with bacterial meningitis. Forty children with bacterial meningitis, at ages ranging from 4 months to 12 years (mean age, 4 years), were enrolled in the study. Within 8 hours after admission (before treatment) and 10 days after clinical and laboratory indications of recovery (after treatment), cerebrospinal fluid and venous blood were collected. Thirty-seven healthy children (mean age, 4 years) were enrolled as control subjects, and only venous blood was collected. Serum total oxidant status, lipid hydroperoxide, oxidative stress index, uric acid, albumin, and ceruloplasmin levels were lower in the patient group after treatment (P<0.05). Serum total antioxidant capacity levels, vitamin C, total bilirubin, and catalase concentrations were not significantly altered by treatment (P>0.05). However, cerebrospinal fluid total oxidant status, lipid hydroperoxide, and oxidative stress index levels were higher, and cerebrospinal fluid total antioxidant capacity levels were lower after treatment than before treatment (P<0.05). In conclusion, we demonstrated that serum oxidative stress was lower, and cerebrospinal fluid oxidative stress was higher, after rather than before treatment in children with bacterial meningitis.

Urinary excretion of oxidative metabolites of bilirubin in subjects with Gilbert syndrome

BACKGROUND AND AIM

Bilirubin is a potent endogenous antioxidant substance. Recent data suggest a direct relationship exists between urinary excretion of biopyrrins, a novel group of bilirubin oxidative metabolites, and severity of oxidative stress. The aim of this study was to evaluate urinary excretion of biopyrrins in subjects with Gilbert syndrome.

METHODS

The study included patients with Gilbert syndrome (n = 33) and healthy blood donors (n = 25). In all subjects complete biochemical tests were conducted along with analysis of urinary excretion of biopyrrins. Linear and logistic regression analyses were used for multiple adjustments of possible confounders/modifiers.

RESULTS

As expected, high serum bilirubin levels were found in the Gilbert syndrome group as compared to controls (27.8 +/- 9.7 vs 9.9 +/- 3.0 micromol/L, P < 0.001). In contrast, urinary levels of biopyrrins were substantially lower in the Gilbert syndrome group as compared to normobilirubinemic control subjects (19.9 +/- 26.0 vs 90.2 +/- 139.1 U/g urinary creatinine, P < 0.001). The Gilbert syndrome group also had very low prevalence odds ratios for urinary biopyrrins above the median of the control values even after adjustment for possibly confounding factors (odds ratio 0.18, 95% confidence interval 0.33-0.94; P = 0.042).

CONCLUSIONS

An inverse relationship was demonstrated between serum bilirubin level and urinary excretion of biopyrrins, which is presumably due to antioxidative effects of elevated serum bilirubin levels in Gilbert syndrome.

The Heme Catabolic Pathway and its Protective Effects on Oxidative Stress‐Mediated Diseases

Bilirubin, the principal bile pigment, is the end product of heme catabolism. For many years, bilirubin was thought to have no physiological function other than that of a waste product of heme catabolism--useless at best and toxic at worst. Although hyperbilirubinemia in neonates has been shown to be neurotoxic, studies performed during the past decade have found that bilirubin has a number of new and interesting biochemical and biological properties. In addition, there is now a strong body of evidence suggesting that bilirubin may have a beneficial role in preventing oxidative changes in a number of diseases including atherosclerosis and cancer, as well as a number of inflammatory, autoimmune, and degenerative diseases. The results also suggest that activation of the heme oxygenase and heme catabolic pathway may have beneficiary effects on disease prevention either through the action of bilirubin or in conjunction with bilirubin. If so, it may be possible to therapeutically induce heme oxygenase, increase bilirubin concentrations, and lower the risk of oxidative stress-related diseases.

Total antioxidant/oxidant status in meningism and meningitis

The objective of this study was to investigate the antioxidant/oxidant status of serum and cerebrospinal fluid in children with meningismus and acute bacterial meningitis. Twenty-three children (age range, 0.75 to 9 years) with fever and meningeal signs that required analysis of the cerebrospinal fluid, but no cytologic or biochemical evidence of meningitis in their serum and cerebrospinal fluid, constituted the meningismus group. Thirty-one children (age range, 0.5 to 10 years) with acute bacterial meningitis constituted the meningitis group. Twenty-nine healthy children (age range, 0.5 to 11 years) were recruited as control subjects. Antioxidant status (ascorbic acid, albumin, thiol, uric acid, total bilirubin, total antioxidant capacity, catalase and ceruloplasmin concentrations) and oxidant status (lipid hydroperoxide and total oxidant status) were measured. The serum antioxidant status was lower, and oxidant status levels higher in both meningitis and meningismus subjects than in the control children (P < 0.001). Cerebrospinal fluid oxidant status was lower in the meningitis group than in the meningismus group (P < 0.05). These results indicate that serum antioxidant status was lower, and serum oxidant status was higher in children in the meningismus and meningitis groups, whereas cerebrospinal fluid oxidant status was higher in the meningismus group than in the meningitis group.

Pneumococcal meningitis in adults: new approaches to management and prevention

Since the virtual eradication of meningitis due to Haemophilus influenzae type B by vaccination in the developed world, pneumococcal meningitis has become the leading cause of bacterial meningitis beyond the neonatal period. Clinical and experimental research has increased our knowledge about the pathophysiology and pathogenesis of the disease over the past decades. Despite the availability of effective antibiotics, supportive care facilities, and recent advances in adjunctive strategies-ie, adjunctive dexamethasone-mortality and morbidity rates associated with pneumococcal meningitis remain unacceptably high. Although preliminary results after the introduction of the pneumococcal conjugate vaccine are promising, the incidence of multidrug-resistant pneumococcal strains is rising worldwide. Here we discuss clinical aspects of pneumococcal meningitis in adults, with focus on pathophysiology, and stress the urgent need for adequate preventive measures and new effective treatments.