Glutathione Conjugation at the Blood-CSF Barrier Efficiently Prevents Exposure of the Developing Brain Fluid Environment to Blood-Borne Reactive Electrophilic Substances.

Exposure of the developing brain to toxins, drugs, or deleterious endogenous compounds during the perinatal period can trigger alterations in cell division, migration, differentiation, and synaptogenesis, leading to lifelong neurological impairment. The brain is protected by cellular barriers acting through multiple mechanisms, some of which are still poorly explored. We used a combination of enzymatic assays, live tissue fluorescence microscopy, and an in vitro cellular model of the blood-CSF barrier to investigate an enzymatic detoxification pathway in the developing male and female rat brain. We show that during the early postnatal period the choroid plexus epithelium forming the blood-CSF barrier and the ependymal cell layer bordering the ventricles harbor a high detoxifying capacity that involves glutathione S-transferases. Using a functional knock-down rat model for choroidal glutathione conjugation, we demonstrate that already in neonates, this metabolic pathway efficiently prevents the penetration of blood-borne reactive compounds into CSF. The versatility of the protective mechanism results from the multiplicity of the glutathione S-transferase isoenzymes, which are differently expressed between the choroidal epithelium and the ependyma. The various isoenzymes display differential substrate specificities, which greatly widen the spectrum of molecules that can be inactivated by this pathway. In conclusion, the blood-CSF barrier and the ependyma are identified as key cellular structures in the CNS to protect the brain fluid environment from different chemical classes of potentially toxic compounds during the postnatal period. This metabolic neuroprotective function of brain interfaces ought to compensate for the liver postnatal immaturity.SIGNIFICANCE STATEMENT Brain homeostasis requires a stable and controlled internal environment. Defective brain protection during the perinatal period can lead to lifelong neurological impairment. We demonstrate that the choroid plexus forming the blood-CSF barrier is a key player in the protection of the developing brain. Glutathione-dependent enzymatic metabolism in the choroidal epithelium inactivates a broad spectrum of noxious compounds, efficiently preventing their penetration into the CSF. A second line of detoxification is located in the ependyma separating the CSF from brain tissue. Our study reveals a novel facet of the mechanisms by which the brain is protected at a period of high vulnerability, at a time when the astrocytic network is still immature and liver xenobiotic metabolism is limited.

Potential biomarkers relating pathological proteins, neuroinflammatory factors and free radicals in PD patients with cognitive impairment: a cross-sectional study.

BACKGROUND: Cognitive impairment strikingly reduces the quality of life of Parkinson's disease (PD) patients. Studies find that pathological proteins, neuroinflammatory factors and free radicals may involve in the pathogenesis of cognitive impairment of PD, however, results are inconclusive. METHODS: We recruited 62 PD patients and 31 healthy controls. PD patients were identified with cognitive impairment, including PD with mild cognitive impairment (PD-MCI) and PD with dementia (PDD) according to the diagnostic criteria for PD-MCI and PDD issued by Movement Disorder Society Task Force. The levels of pathological proteins, including ß-amyloid 1-42 (Aß1-42),Total-tau (T-tau) and phosphorelated tau (P-tau), neuroinflammatory factors,including tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interferon-γ (INF-γ) and prostaglandin E2 (PGE2), free radicals, including hydroxyl radical (·OH), hydrogen peroxide (H2O2) and nitric oxide (NO) in cerebrospinal fluid(CSF) were detected. The levels of above factors in CSF were compared among healthy controls and patients with and without cognitive impairment. Correlation analyses were performed between Montreal Cognitive Assessment (MoCA) score and the levels of above factors in CSF. RESULTS: T-tau level in CSF from PD-CI patients are significantly elevated comparing with those without cognitive impairment and controls (P = 0.016 and 0.004, respectively). The levels of P-tau (S396) and · OH in PD-CI patients are significantly higher than controls (P = 0.001 and 0.014, respectively). IL-6 levels in PD-CI patients are strikingly enhanced comparing with those without cognitive impairment (P = 0.005). MoCA score is negatively correlated with the levels of T-tau (r = -0.340), P-tau (S396) (r = -0.448), IL-6 (r = -0.489) and · OH (r = -0.504) in PD-CI patients. CONCLUSIONS: Elevated levels of T-tau, P-tau (S396), IL-6 and · OH in CSF are significantly correlated with cognitive impairment in PD patients. This investigation may suggest the potential biomarkers relating pathological proteins, neuroinflammatory factors and free radicals in PD patients with cognitive impairment.

Viral loads of cerebrospinal fluid in infants with enterovirus meningitis.

For a better understanding of the role of the viral load, free radicals, and cytokines in viral meningitis, we surveyed cerebrospinal fluid (CSF) obtained from patients below 1 year of age who showed positive for enterovirus. In their first examinations interleukin (IL)-6 and free radicals increased whereas pleocytosis was rarely observed. IL-6 decreased within the short period. Viral loads and free radicals increased simultaneously. IL-6 and free radicals of CSF are helpful for diagnosis and treatment of viral meningitis at an early stage.

Diagnostic and predictive value of CSF d-ROM level in influenza virus-associated encephalopathy.

The aim of this study was to assess the validity of serum and CSF oxidative status of patients with IE in their initial stage through the d-ROM (Diacron-Reactive Oxygen Metabolites, Italy) test, compared to those with other neurological diseases. The study was conducted on the following four groups: (1) influenza virus-associated encephalopathy (IE, n = 8), including four patients showing neurological sequelae or mortal; (2) influenza virus-associated febrile seizures (IFS, n = 11); (3) febrile convulsion (FC, n = 10): (4) enterovirus-associated encephalopathy (EE, n = 4), including one patient with neurological sequelae. The CSF d-ROM levels in the IE group were significantly higher than those in the IFS and the FC groups but not in the EE group. In addition, general laboratory findings such as leukocytes, platelets, C-reactive protein, aspartate aminotransferase, creatinine, creatinine kinase and LDH, including interleukin-6 (IL-6), were analyzed in each group. The CSF d-ROM levels in the IE group were significantly higher than those in the IFS and FC groups but not in the EE group. As for the serum d-ROM levels and general laboratory findings, with the exception of CSF IL-6 levels in IE, no significant differences were detected compared with the other groups. In patients with IE, the CSF d-ROM levels could be a valid predictive biomarker of the severity, and oxidative stress may be related to the pathogenesis of IE.

Cerebrospinal fluid free-radical peroxidation products and cognitive functioning patterns differentiate varieties of normal pressure hydrocephalus.

The aims of the study were as follows: first, to verify the hypothesis that free radical peroxidation may be one of the factors implicated in pathophysiology of normal pressure hydrocephalus (NPH) and, second, to find out whether these biochemical characteristics together with neuropsychological cognitive deficits can differentiate between various types of NPH. This provides prognostic criteria for selection of patients for shunt surgery. Lipid peroxidation was measured in terms of thiobarbituric acid-reactive material (TBAR) and protein sulphydryl (SH) groups were measured as CSF content. Cognitive deficits were assessed using a number of neuropsychological tests. In the sample of NPH patients (n = 24), three categories were distinguished using these criteria: idiopathic active hydrocephalus (A), arrested hydrocephalus (AH), and post-traumatic hydrocephalus (PT). TBAR levels for NPH patients were higher than that of controls without CNS pathology (n = 2). Moreover, NPH patients had increased levels of total and soluble protein groups, and decreased levels of protein SH groups, which suggests the occurrence of processes that activate peroxidation of free radicals in normal pressure hydrocephalus. Levels of these indicators varied across NPH types. Two categories of NPH patients, with active (A) or posttraumatic (PT) hydrocephalus differed significantly from the controls (C)--their TBAR levels were 0.58, 0.56 and 0.28 nmol/mg protein, respectively; soluble SH levels: 41.5; 58.15 and 11.3 nmol/mg protein, and protein SH levels: 34.3, 21.8 and 57.5 nmol/mg protein. In PT group, many individual differences were noticed. These findings seem promising because the studied biochemical indicators may serve as additional diagnostic criteria for selection of NPH patients for shunting.

CSF interleukin-1 beta, tumor necrosis factor-alpha and free radicals production in relation to clinical outcome in acute bacterial meningitis.

OBJECTIVE: To study the relationship of CSF IL-1 beta and TNF-alpha with free radicals in acute bacterial meningitis (ABM) and to evaluate the clinical outcome in relation to the levels of these cytokines and free radicals in CSF. DESIGN: Prospective with controls. SETTING: Referral unit of a teaching hospital. METHODS: 32 children between 3m-12 yrs of age with proven acute bacterial meningitis comprised the study group. In the control group, 20 children with febrile seizures were included. CSF cytokines- Interleukin Ib and tumour necrosis factor a,free radicals O(2)-, H(2)O(2) and enzymes SOD and CPK were measured in all the children. RESULTS: CSF IL-Ib and TNF-a concentration were markedly elevated in children with ABM (441.5 +/- 216.1 pg/ml, and 1009 +/- 529.1 pg/ml, respectively) as compared to controls (52.67 +/- 6.92 pg/ml, and 86.42 +/- 16.24 pg/ml) (p <0.0001). Free radicals viz., superoxide anion, hydrogen peroxide production and enzymes creatinine phosphokinase and superoxide dismutase were also significantly elevated in ABM as compared to controls. There was direct correlation of CSF cytokines with CSF cytology, protein and free radicals production in ABM. Patients who expired or had neurological sequelae had markedly elevated concentrations of cytokines and free radicals. CONCLUSION: IL-I beta, TNF-alpha and free radicals are significantly elevated in CSF of patients with ABM. The concentration of these cytokines correlated well with free radical production, and with routinely measured CSF parameters and had a direct bearing on outcome of ABM