The Association of Essential Metals with APOE Genotype in Alzheimer's Disease.

BACKGROUND: The major confirmed genetic risk factor for late-onset, sporadic Alzheimer's disease (AD) is variant ɛ4 of apolipoprotein E gene (APOE). It is proposed that ApoE, a protein involved in transport of cholesterol to neurons can cause neurodegeneration in AD through interaction with metals. Previous studies mostly associated copper, iron, zinc, and calcium with ApoE4-mediated toxicity. OBJECTIVE: To test the association of essential metals with APOE genotype. METHODS: We compared plasma and cerebrospinal fluid (CSF) levels of copper, zinc, iron, sodium, magnesium, calcium, cobalt, molybdenum, manganese, boron, and chromium, and CSF ferritin levels among AD, mild cognitive impairment (MCI) patients, and healthy controls (HC) with different APOE genotype. RESULTS: Sodium, copper, and magnesium levels were increased in carriers of ɛ4 allele. Additionally, the increase in sodium, calcium and cobalt plasma levels was observed in carriers of ɛ4/ɛx genotype. The decrease in boron plasma levels was observed in carriers of ɛ4 allele and ɛ4/ɛ4 genotype. Additionally, CSF zinc levels as well as plasma sodium levels were increased in AD patients compared to HC. CONCLUSION: These results indicate that the molecular underpinnings of association of essential metals and metalloids with APOE should be further tested and clarified in vivo and in vitro.

Cerebrospinal Fluid Metals and the Association with Cerebral Small Vessel Disease.

BACKGROUND: Brain metal homeostasis is essential for brain health, and deregulation can result in oxidative stress on the brain parenchyma. OBJECTIVE: Our objective in this study was to focus on two hemorrhagic MRI manifestations of small vessel disease [cerebral microbleeds (CMBs) and cortical superficial siderosis (cSS)] and associations with cerebrospinal fluid (CSF) iron levels. In addition, we aimed to analyze CSF biomarkers for dementia and associations with CSF metal levels. METHODS: This is a cross-sectional study of 196 patients who underwent memory clinic investigation, including brain MRI. CSF was collected and analyzed for metals, amyloid-ß (Aß) 42, total tau (T-tau), and phosphorylated tau (P-tau), and CSF/serum albumin ratios. Statistical analyses were performed using generalized linear models. RESULTS: No significant difference was found between CSF metal levels across diagnostic groups. Higher iron and copper levels were associated with higher CSF levels of Aß42, T-tau, P-tau, and CSF/serum albumin ratios (p < 0.05). Zinc was associated with higher CSF/serum albumin ratios. There was no significant association between CMBs or cSS and CSF iron levels. An increase in CSF iron with the number of CMBs was seen in APOEɛ4 carriers. CONCLUSION: CSF iron levels are elevated with cerebral microbleeds in APOEɛ4 carriers, with no other association seen with hemorrhagic markers of small vessel disease. The association of elevated CSF iron and copper with tau could represent findings of increased neurodegeneration in these patients.

Species fractionation in a case-control study concerning Parkinson's disease: Cu-amino acids discriminate CSF of PD from controls.

BACKGROUND: Parkinson's disease is affecting about 1% of the population above 65 years. Improvements in medicine support prolonged lifetime which increases the total concentration of humans affected by the disease. It is suggested that occupational and environmental exposure to metals like iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn) can influence the risk for Parkinson's disease. These metals play a key role as cofactors in many enzymes and proteins. METHODS: In this case-control study, we investigated the Mn-, Fe-, Cu- and Zn-species in cerebrospinal fluid (CSF) by size-exclusion chromatography hyphenated to inductively coupled plasma mass spectrometry (SEC-ICP-MS) and the total concentration of these metals by inductively coupled plasma sector field mass spectrometry (ICP-sf-MS). RESULTS: The investigation of total metal concentration and speciation provided only minor changes, but it produced strong significance for a number of ratios. The analysis revealed a strong change in the ratio between total concentration of Fe and the amino acid-fraction of Cu. This could be observed when analyzing both the respective element concentrations of the fraction (which also depends on individual variation of the total element concentration) as well as when being expressed as percentage of total concentration (normalization) which more clearly shows changes of distribution pattern independent of individual variation of total element concentrations. CONCLUSION: Speciation analysis, therefore, is a powerful technique to investigate changes in a case-control study where ratios of different species play an important role.

Decreased circulating Zinc levels in Parkinson's disease: a meta-analysis study.

There is no consensus on the involvement of zinc (Zn) dysfunctions in Parkinson's Disease (PD). We performed a meta-analysis to evaluate whether circulating Zn levels in the serum, plasma, and cerebrospinal fluid (CSF) are altered in PD. Twenty-three published studies were selected by searching the databases of PubMed and China National Knowledge Infrastructure (CNKI). A total of 803 PD patients and 796 controls, 342 PD patients and 392 controls, and 135 PD patients and 93 controls were included to study Zn levels in the serum, plasma, and CSF, respectively. Our meta-analysis showed that the serum Zn levels were significantly lower in PD patients compared with health controls (SMD = -0.59; 95% CI [-1.06, -0.12]; P = 0.014). A reduced Zn levels in PD patients were found when serum and plasma studies were analyzed together (SMD = -0.60, 95% CI [-0.98; -0.22]; p = 0.002). PD patients had a tendency toward reduced CSF Zn levels compared with health controls (SMD = -0.50; 95% CI [-1.76, 0.76]; P = 0.439), but no statistical significance was obtained and this data did not allow conclusions due to a small sample size of CSF studies. This study suggests that reduced Zn levels in the serum and plasma are associated with an increased risk for PD.

Significance of Low Nanomolar Concentration of Zn2+ in Artificial Cerebrospinal Fluid.

Much less attention has been paid to Zn2+ in artificial cerebrospinal fluid (ACSF), i.e., extracellular medium, used for in vitro slice experiments than divalent cations such as Ca2+. Approximately 2 mM Ca2+ is added to conventional ACSF from essentiality of Ca2+ signaling in neurons and glial cells. However, no Zn2+ is added to it, even though the importance of Zn2+ signaling in them is recognizing. On the other hand, synaptic Zn2+ homeostasis is changed during brain slice preparation. Therefore, it is possible that not only neuronal excitation but also synaptic plasticity such as long-term potentiation is modified in ACSF without Zn2+, in which original physiology might not appear. The basal (static) levels of intracellular (cytosolic) Zn2+ and Ca2+ are not significantly different between brain slices prepared with conventional ACSF without Zn2+ and pretreated with ACSF containing 20 nM ZnCl2 for 1 h. In the case of mossy fiber excitation, however, presynaptic activity assessed with FM 4-64 is significantly suppressed in the stratum lucidum of brain slices pretreated with ACSF containing Zn2+, indicating that hippocampal excitability is enhanced in brain slices prepared with ACSF without Zn2+. The evidence suggests that low nanomolar concentration of Zn2+ is necessary for ACSF. Furthermore, exogenous Zn2+ has opposite effect on LTP induction between in vitro and in vivo experiments. It is required to pay attention to extracellular Zn2+ concentration to understand synaptic function precisely.

Negative correlation between CSF zinc level and anxiety in male Chinese subjects.

Zinc is crucial for brain development and psychiatric regulation. In the present study, we investigated the relationship between cerebrospinal fluid (CSF) zinc level and anxiety in a group of male Chinese subjects. Results demonstrated that zinc levels had no considerable interindividual variations, ranging from 8.37 to 16.83µm. Correlation analyses revealed that CSF Zinc levels were positively correlated with education years (r=0.225, p=0.024) and negatively correlated with SAS scores (r=-0.287, p=0.004), but not associated with age or BMI. In conclusion, this present study suggests that CSF zinc level is associated with anxiety.

Zinc in Alzheimer's Disease: A Meta-Analysis of Serum, Plasma, and Cerebrospinal Fluid Studies.

To evaluate whether zinc levels in serum, plasma, and cerebrospinal fluid are altered in Alzheimer's disease (AD), we performed meta-analyses of 27 studies on the topic published from 1983 to 2014. The subjects' sample obtained by merging studies was a pooled total of 777 AD subjects and 1,728 controls for serum zinc studies, 287 AD subjects and 166 controls for plasma zinc, and of 292 AD subjects and 179 controls for CSF zinc. The main result of this meta-analysis is the very high heterogeneity among the studies either in demographic terms or in methodological approaches. Although we considered these effects in our analyses, the heterogeneity persisted and it has to be taken into account in the interpretation of the results. Our meta-analysis indicated that serum zinc appears significantly decreased in AD patients compared with healthy controls, and this result is confirmed when serum and plasma studies were analyzed together. If we considered the age-matched studies, the meta-analysis carried out on only six studies showed no significant difference in zinc levels between AD and healthy controls (SMD =-0.55, 95% CI (-1.18; 0.09); p = 0.094; I2 = 91%). In the light of these findings, we speculated about the possibility that the decreases observed could indicate a possible dietary zinc deficiency and we suggested that the possible involvement of zinc alterations in AD may have an interplay with copper metabolism.

Upregulation of zinc transporter 2 in the blood-CSF barrier following lead exposure.

Zinc (Zn) is an essential element for normal brain function; an abnormal Zn homeostasis in brain and the cerebrospinal fluid (CSF) has been implied in the etiology of Alzheimer's disease (AD). However, the mechanisms that regulate Zn transport in the blood-brain interface remain unknown. This study was designed to investigate Zn transport by the blood-CSF barrier (BCB) in the choroid plexus, with a particular focus on Zn transporter-2 (ZnT2), and to understand if lead (Pb) accumulation in the choroid plexus disturbed the Zn regulatory function in the BCB. Confocal microscopy, quantitative PCR and western blot demonstrated the presence of ZnT2 in the choroidal epithelia; ZnT2 was primarily in cytosol in freshly isolated plexus tissues but more toward the peripheral membrane in established choroidal Z310 cells. Exposure of rats to Pb (single ip injection of 50 mg Pb acetate/kg) for 24 h increased ZnT2 fluorescent signals in plexus tissues by confocal imaging and protein expression by western blot. Similar results were obtained by in vitro experiments using Z310 cells. Further studies using cultured cells and a two-chamber Transwell device showed that Pb treatment significantly reduced the cellular Zn concentration and led to an increased transport of Zn across the BCB, the effect that may be due to the increased ZnT2 by Pb exposure. Taken together, these results indicate that ZnT2 is present in the BCB; Pb exposure increases the ZnT2 expression in choroidal epithelial cells by a yet unknown mechanism and as a result, more Zn ions may be deposited into the intracellular Zn pool, leading to a relative Zn deficiency state in the cytoplasm at the BCB.

The role of metallobiology and amyloid-ß peptides in Alzheimer's disease.

The biggest risk factor for Alzheimer's disease is the process of ageing, but the mechanisms that lead to the manifestation of the disease remain to be elucidated. Why age triggers the disease is unclear but an emerging theme is the inability for a cell to efficiently maintain many key processes such as energy production, repair, and regenerative mechanisms. Metal ions are essential to the metabolic function of every cell. This review will explore the role and reported changes in metal ions in Alzheimer disease, particularly the brain, blood and cerebral spinal fluid, emphasizing how iron, copper and zinc may be involved through the interactions with amyloid precursor protein, the proteolytically cleaved peptide amyloid-beta (Aß), and other related metalloproteins. Finally, we explore the monomeric makeup of possible Aß dimers, what a dimeric Aß species from Alzheimer's disease brain tissue is likely to be composed of, and discuss how metals may influence Aß production and toxicity via a copper catalyzed dityrosine cross-link.

Concentration of calcium and magnesium and trace elements (zinc, copper, iron and manganese) in cerebrospinal fluid: a try of a pathophysiological classification.

The aim of this study is to analyze the variation of the elements (Ca, Mg, Cu, Fe, Zn and Mn) in normal and pathological CSF and develop a classification basing on the increases in cells and proteins and taking into account these variations. A total of 173 cerebrospinal fluids were analyzed. Of these, 37 fulfilled the criteria of normality and, after clinical exploration, were considered to be healthy (control group). The remaining 136 CSFs (pathological group) belonged to people for whom some neurological pathology had been observed in the clinical exploration and whose CSF analysis presented some abnormality. CSF was extracted by puncture in the lumbar cistern. The analysis of metals was performed by atomic absorption spectrophotometry. The statistical values (mean±standard deviation) obtained for each element analyzed in control group were as follows: Ca (mg/dL): 4.95±0.70; Mg (mg/dL): 2.74±0.10; Cu (µg/dL): 15.70±13.50; Fe (µg/dL): 13.10±3.60; Zn (µg/dL): 17.40±9.50 and Mn (µg/dL): 2.50±0.70. In the pathological CSFs, significant increases were found (p<0.050) in relation to the control group for Ca, Cu, Fe, Zn and Mn in groups with an increase of both cells and proteins. A significant decrease of Mg (p<0.050) was found in the groups with cell and protein increases. Given the results obtained in the different subgroups of the proposed classification, we conclude that it is necessary to further categorize the patients' diagnostics in the different subgroups. This would help to validate the classification.

Zinc and copper modulate Alzheimer Abeta levels in human cerebrospinal fluid.

Abnormal interaction of beta-amyloid 42 (Abeta42) with copper, zinc and iron induce peptide aggregation and oxidation in Alzheimer's disease (AD). However, in health, Abeta degradation is mediated by extracellular metalloproteinases, neprilysin, insulin degrading enzyme (IDE) and matrix metalloproteinases. We investigated the relationship between levels of Abeta and biological metals in CSF. We assayed CSF copper, zinc, other metals and Abeta42 in ventricular autopsy samples of Japanese American men (N=131) from the population-based Honolulu Asia Aging Study. There was a significant inverse correlation of CSF Abeta42 with copper, zinc, iron, manganese and chromium. The association was particularly strong in the subgroup with high levels of both zinc and copper. Selenium and aluminum levels were not associated to CSF Abeta42. In vitro, the degradation of synthetic Abeta substrate added to CSF was markedly accelerated by low levels (2microM) of exogenous zinc and copper. While excessive interaction with copper and zinc may induce neocortical Abeta precipitation in AD, soluble Abeta degradation is normally promoted by physiological copper and zinc concentrations.

CSF Mg and Ca as diagnostic markers for dementia with Lewy bodies.

Accumulating evidence implicates a role for altered metal homeostasis in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease (AD). However, few investigations have addressed this issue in dementia with Lewy bodies (DLB). The aim of the present study was to investigate metal concentrations in cerebrospinal fluid (CSF) and plasma from patients with DLB and other neurodegenerative disorders. To that end, CSF and plasma samples were collected from 29 patients with DLB, 174 patients with AD, 90 patients with AD with minor vascular components, and 51 healthy volunteers. Total concentrations of Mg, Ca, Mn, Fe, Cu, Zn, Rb, Sr, and Cs were determined using mass spectrometry. Patients with DLB had elevated Ca and Mg levels in CSF and Mg levels in plasma as compared to all other groups (p<0.001). Furthermore, a combination of CSF-Mg and CSF-Ca could distinguish DLB from AD with a sensitivity of 93% and a specificity of 85%. Cu levels in both CSF and plasma tended to be higher in DLB compared to the other groups, but these trends failed to reach significance after correction for multiple comparisons. Mn, Fe, Zn, Rb, and Sr concentration in CSF or plasma were similar in all groups. The observed elevations of CSF-Mg, CSF-Ca and CSF-Cu may contribute to or be associated with the neurodegenerative process in DLB. Furthermore, determination of CSF-Mg and CSF-Ca concentration may be a valuable tool in distinguishing DLB from AD.

Speciation analysis of selected metals and determination of their total contents in paired serum and cerebrospinal fluid samples: An approach to investigate the permeability of the human blood-cerebrospinal fluid-barrier.

Neurodegenerative diseases like Alzheimer's disease and Parkinson's disease are gaining increasing relevance in our aging society. However, the complex multifactorial mechanisms of these diseases are not sufficiently understood yet. Several studies indicate that metal ions play an important role in the promotion of these diseases. Consequently, the transport pathways of metals and their species to the brain are of special interest. Following oral or inhalative uptake metals are absorbed and distributed via the blood stream in the body. Transport into the brain requires crossing of the neural barriers. Our study focuses on the investigation of the permeability of the blood-cerebrospinal fluid (CSF)-barrier for selected metals (Mn, Fe, Cu, Zn, Mg and Ca). For the first time paired human serum and CSF samples obtained from a neurological department were characterised for total metal concentrations and metal species. For CSF few data are available in the literature on total metal contents and applications of element speciation analysis in CSF samples are rare. In our study mean CSF/serum ratios (n=29) were 0.7 for Mn, 0.02 for Fe, 0.02 for Cu, 0.03 for Zn, 1.3 for Mg and 0.5 for Ca. Size exclusion chromatography (SEC) online with inductively coupled plasma mass spectrometry was further developed for the size characterisation of the metal species in CSF and serum with limits of detection of 0.4microgL(-1) for Fe, 0.01microgL(-1) for Mn, 0.2microgL(-1) for Cu, 0.2microgL(-1) for Zn, 0.6microgL(-1) for Mg and 3.8microgL(-1) for Ca in the eluate from the HPLC column. Apart from Mn the application of this technique has not been published for metal speciation in CSF, yet. In the case of some Mn species it turned out that methanol, which was contained in the mobile phase of a SEC method previously published from our group on qualitative characterisation of Mn species, was interfering with the quantification. The modified method developed in this work (with NaCl but without methanol in the mobile phase; use of internal standard) allowed reliable quantification. The results clearly indicate changes in the metal species pattern due to different permeation behaviour at the blood-CSF-barrier. As part of the method validation the relative stability of complexes of albumin, transferrin and citrate with Mn, Fe, Cu and Zn was investigated.

Zinc concentration in serum and cerebrospinal fluid simultaneously decrease in children with febrile seizure: findings from a prospective study in Bangladesh.

OBJECTIVE: Since the underlying mechanisms of febrile seizure (FS) having multi-factorial aetiology yet remains unclear, we conducted this prospectively designed cross-sectional study to determine if there was any simultaneous change in zinc (Zn) concentration (conc.) in serum and cerebrospinal fluid (CSF) among the FS children in comparison to their matched non-seizure febrile (NSF) peers. METHODS: Zn concentration (level) in both serum (intravenous blood) and CSF (lumber puncture: LP) of 50 children with FS and 30 NSF peers (serving as control) were measured employing graphite furnace atomic absorbance spectrophotometer. Data were analysed to compare Zn level between two groups using appropriate statistical tools employing SPSS/Windows 12.0. RESULTS: Mean Zn conc. in both serum and CSF was less in FS children (464.60 +/- 64.57 and 46.28 +/- 7.46, respectively) than their matched NSF peers (749.33 +/- 73.19 microg/L and 111.28 +/- 19.11 microg/L, respectively) showing significant differences both in serum (p < 0.001) and CSF (p < 0.001). None of serum or CSF-Zn differed significantly with age, degree and duration of fever between FS and NSF peers. CSF-Zn among these children showed an upward trend in LP specimen taken beyond 12 h following FS episodes. CONCLUSION AND RECOMMENDATION: Serum and CSF-Zn simultaneously decreased in FS children in comparison to their matched NSF peers. Further prospectively designed multicentral studies are recommended to conduct in geographically diverse regions involving larger sample to confirm or refute our findings. It remains crucial in standardizing/strengthening national seizure prevention protocol with adequate Zn supplementation.

Separation of proteins including metallothionein in cerebrospinal fluid by size exclusion HPLC and determination of trace elements by HR-ICP-MS.

A method to study the protein binding patterns of trace elements in human cerebrospinal fluid (CSF) is described. Proteins in CSF samples were separated by size exclusion chromatography combined with high performance liquid chromatography (SEC-HPLC). The column was calibrated to separate proteins in the molecular weight range 6-70 kDa. Fractions were then analyzed off-line for trace elements using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). We were able to accurately determine more than 10 elements of clinical interest in the CSF fractions. Results are presented for Cd, Mn, Fe, Pb, Cu and Zn. The total concentrations of 16 trace elements in human plasma and CSF are also presented. The method was able to differentiate the relative contribution of metallothionein and other proteins towards metal binding in human CSF.

Niveles de zinc en líquido prostático de pacientes con patologías de próstata / Zinc levels in prostatic fluid of patients with prostate pathologies

La próstata es una glándula que rodea la uretra posterior en el hombre, junto a las vesículas seminales, produce los líquidos prostático y seminal. La prostatitis, la hiperplasia benigna y el cáqncer de próstata son las patologías más frecuentes que la afectan. El zinc es un elemento importante en la composición química del líquido prostático y juega un papel fundamental en la inmunología de los fenómenos infecciosos y neoplásicos. El objetivo de la presente investigación fue determinar las concentraciones de zinc en líquido prostático de pacientes con patología de dicha glándula a fin de que sirva como parámetro para su diagnóstico y fundamento para una nueva forma terapéutica. Se estudiaron 30 pacientes con patología de próstata y 10 sujetos sanos, de quienes se obtuvo una muestra de líquido prostático mediante masaje prostático para luego determinar la concentración de zinc a través de espectrometría de absorción atómica con atomización electrónica (ETA-AAS). En los 11 pacientes con hiperplasia de próstata se encontró una concentración promedio de zinc de 15.087,78 µmol/dL, los 10 pacientes con prostatitis tuvieron una concentración de 863,33 µmol/dL y los 9 pacientes con diagnóstico de cáncer de próstata presentaron una concentración de zinc de 1.027,60 µmol/dL. La concentración promedio de zinc en el grupo control (10 personas) fue de 7.467,52 µmol/dL. En conclusión, la concentración baja de zinc en los pacientes con prostatitis y cáncer de próstata, con respecto al grupo control, permite plantear la posibilidad de utilizar suplementos de zinc como terapia complementaria en los pacientes con prostatitis, y la determinación de zinc, junto al antígeno prostático, representa un nuevo elemento para los casos en que exista dudas sobre el diagnóstico de cáncer de próstata y de hiperplasia prostática benigna.

[Determination of trace elements in cerebrospinal fluid (CSF) of patients suffering cerebrovascular disease by atomic absorption spectrometry].

The contents of some trace elements such as zinc, copper, iron and cadmium in cerebrospinal fluid (CSF) of normal persons and the patients who suffered cerebral hemorrhage or infarction were determined directly by atomic absorption spectrometry. The method is simple and convenient with a recovery ratio by standard addition being 97.6% to 104.8%, and a relative standard deviation (RSD) is lower than 5%. The test showed that except for the content copper lower than normal, the patients suffering cerebrovascular disease have much higher contents of zinc, iron and cadmium. The result provides useful data for studying the relation between the contents of these trace elements and cerebrovascular disease, as well as diagnosing, treating and preventing this disease.

Perinatal omega-3 polyunsaturated fatty acid supply modifies brain zinc homeostasis during adulthood.

Dietary omega-3 polyunsaturated fatty acid (PUFA) influences the expression of a number of genes in the brain. Zinc transporter (ZnT) 3 has been identified as a putative transporter of zinc into synaptic vesicles of neurons and is found in brain areas such as hippocampus and cortex. Neuronal zinc is involved in the formation of amyloid plaques, a major characteristic of Alzheimer's disease. The present study evaluated the influence of dietary omega-3 PUFA on the expression of the ZnT3 gene in the brains of adult male Sprague-Dawley rats. The rats were raised and/or maintained on a control (CON) diet that contained omega-3 PUFA or a diet deficient (DEF) in omega-3 PUFA. ZnT3 gene expression was analyzed by using real-time PCR, free zinc in brain tissue was determined by zinquin staining, and total zinc concentrations in plasma and cerebrospinal fluid were determined by atomic absorption spectrophotometry. Compared with CON-raised animals, DEF-raised animals had increased expression of ZnT3 in the brain that was associated with an increased level of free zinc in the hippocampus. In addition, compared with CON-raised animals, DEF-raised animals had decreased plasma zinc level. No difference in cerebrospinal fluid zinc level was observed. The results suggest that overexpression of ZnT3 due to a perinatal omega-3 PUFA deficiency caused abnormal zinc metabolism in the brain. Conceivably, the influence of dietary omega-3 PUFA on brain zinc metabolism could explain the observation made in population studies that the consumption of fish is associated with a reduced risk of dementia and Alzheimer's disease.

Manganese, copper, and zinc in cerebrospinal fluid from patients with multiple sclerosis.

The concentrations of manganese, copper, and zinc in cerebrospinal fluid (CSF) from patients with multiple sclerosis (MS) and patients with no known neurological disease (control group) were measured. Manganese and copper levels were determined by two different analytical methods: atomic absorption spectrometry (AAS) and high-resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS), whereas zinc levels were determined by HR-ICP-MS only. Manganese levels (mean+/-SEM) were significantly decreased in the CSF of MS patients (1.07+/-0.13 microg/L, ICP-MS; 1.08+/-0.11 microg/L, AAS) compared to the levels in the control group (1.78+/-0.26 microg/L, ICP-MS; 1.51+/-0.17 microg/L, AAS). Copper levels were significantly elevated in the CSF of MS patients (10.90+/-1.11 microg/L; ICP-MS, 11.53+/-0.83 microg/L, AAS) compared to the levels in the control group (8.67+/-0.49 microg/L, ICP-MS; 9.10+/-0.62 microg/L, AAS). There were no significant differences between the CSF zinc levels of MS and control patients. The physiological basis for the differences in manganese and copper concentrations between MS patients and controls is unknown, but could be related to alterations in the manganese- containing enzyme glutamine synthetase and the copper-containing enzyme cytochrome oxidase.