Intra vitam lumbar and post mortem ventricular cerebrospinal fluid immunoreactive interleukin-6 in Alzheimer's disease patients

OBJECTIVES: In view of contradictory findings in previous studies, to examine the diagnostic value of interleukin-6 measurements in cerebrospinal fluid (CSF) of Alzheimer's disease patients. MATERIAL AND METHODS: Interleukin-6-immunoreactivity (IL-6-IR) was measured in 169 intra vitam lumbar and 21 post mortem ventricular CSF samples of patients with probable and neuropathologically confirmed Alzheimer's disease (AD), non-AD dementias (NAD), neurological disorders without cognitive impairment (OND) and controls (CON) using a specific sandwich enzyme immunoassay. RESULTS: Intra vitam lumbar samples had significantly elevated (P < 0.03) IL-6-IR not only in the AD, but also in the NAD and OND group compared with controls. AD patients with late onset (> 65 years) had slightly (P > 0.05) higher values than patients with early onset (< 65 years). In post mortem ventricular fluid, differences among groups did not reach significance (P > 0.05). CONCLUSION: We conclude that elevations of CSF IL-6-IR can not serve as a diagnostic marker of the disease, but, hypothetically, could reflect presence or activity of IL-6 mediated immunological phenomena in single AD patients.     

Dexamethasone decreases cerebrospinal fluid soluble tumor necrosis factor receptor 1 levels in bacterial meningitis

It is known that the use of adjunctive dexamethasone in bacterial meningitis reduces audiologic and neurologic sequelae. The cerebrospinal fluid (CSF) level of soluble tumor necrosis factor 1 (sTNFR1) is an important indicator of neurologic sequelae in bacterial meningitis. We measured the CSF levels of IL-6 and sTNFR1 before administration of antibiotics (CSF1) and 1-3 days after administration of antibiotics (CSF2) in nine patients with bacterial meningitis who received dexamethasone sodium and five without dexamethasone. The CSF2 IL-6 levels of patients with/without dexamethasone were significantly lower than for CSF1 IL-6 levels (p = 0.0077, and p = 0.0431, respectively). There were no significant differences of the ratio of CSF2/CSF1 IL-6 levels between patients with dexamethasone and those without dexamethasone. CSF2 sTNFR1 levels of patients with dexamethasone were significantly lower than for CSF1 sTNFR1 levels (p = 0.0208). However, CSF2 sTNFR1 levels of patients without dexamethasone were significantly higher than for CSF1 sTNFR1 levels (p = 0.0422). The ratio of CSF2/CSF1 sTNFR1 levels of patients with dexamethasone was significantly lower than that without dexamethasone (p = 0.0063). Our present study suggests that dexamethasone inhibits increase of CSF sTNFR1 levels after antibiotics therapy in bacterial meningitis.     

Discriminant power of combined cerebrospinal fluid τ protein and of the soluble interleukin-6 receptor complex in the diagnosis of Alzheimer's disease

Alzheimer's disease (AD) still can only be definitively diagnosed with certainty by examination of brain tissue. There is a great need for a noninvasive, sensitive and specific in vivo test for AD. We combined cerebrospinal fluid analyses of τ protein (levels were significantly increased in AD patients [p=0.0001]), a putative marker of neuronal degeneration, with components of the soluble interleukin-6 receptor complex (sIL-6RC: IL-6, soluble IL-6 receptor and soluble gp130), putative markers of neuroregulatory and inflammatory processes in the brain. A stepwise multivariate discriminant analysis revealed that τ protein and soluble gp130 (levels were significantly reduced in AD subjects [p=0.007]), the affinity converting and signal-transducing receptor of neuropoietic cytokines, maximized separation between the investigated groups. The discriminant function predicted 23 of 25 clinically diagnosed AD patients (sensitivity 92%) with mild to moderate dementia correctly as having AD. Furthermore, 17 of 19 physically and cognitively healthy age-matched control subjects (specificity 90%) were accurately distinguished by this test. Later predicting with the jackknife procedure each case in turn through the remaining patient group, the discriminant function remained stable. Our data suggest that multivariate discriminant analysis of combined CSF τ protein and sIL-6RC components may add more certainty to the diagnosis of AD, however, the method will need to be extended to an independent group of patients, comparisons and control subjects to assess the true applicability.     

难治性颞叶癫痫脑组织IL-6、IL-6受体及sIL-6R、 sgp130的表达及意义

目的 探讨IL-6、IL-6膜受体(IL-6R)及其下游信号转导相关分子在颞叶癫痫(TLE)发生中的作用. 方法 选择自2010年1月至2010年12月在第三军医大学新桥医院神经外科行手术治疗的TLE患者40例(TLE组),同期行手术治疗的外伤、高血压脑出血等患者40例(对照组);收集其手术过程中切除的颞叶组织.利用RT-PCR、ELISA等方法分析IL-6、IL-6R、sIL-6R以及sgp130的mRNA或蛋白水平的表达变化情况. 结果 TLE组和对照组中均可检测到IL-6和IL-6R mRNA的表达,但TLE组致病灶中IL-6和IL-6R mRNA水平均显著高于对照组,差异有统计学意义(P＜0.05).ELISA结果提示,sIL-6R在TLE组致痫灶中的表达量与对照组比较明显增高,差异有统计学意义(P＜0.05);sgpl30的含量略高于对照组,差异没有统计学意义(P＞0.05). 结论 局部高浓度的IL-6通过经典信号转导或者跨信号转导机制作用于TLE病灶细胞,影响这些细胞的生物学功能,参与癫痫发生过程.     

Increased cerebrospinal fluid interleukin-6 levels in patients with schizophrenia and those with major depressive disorder

Elevated peripheral levels of interleukin-6 (IL-6) are common findings in schizophrenia and depression. However, previous studies that measured cerebrospinal fluid (CSF) IL-6 levels in these disorders reported controversial results. The present study examined whether CSF IL-6 levels are altered in patients with schizophrenia and those with depression. Lumbar punctures were performed in 32 patients with schizophrenia, 30 with major depressive disorder (MDD), and 35 healthy controls. Serum samples were simultaneously collected from all subjects in the patient groups and from 32 of the control group. CSF and serum IL-6 levels were determined by enzyme-linked immunosorbent assay. Both the patients with schizophrenia and MDD had significantly higher CSF IL-6 levels compared to the controls (schizophrenia: P = 0.0027; MDD: P = 0.012). IL-6 levels were significantly higher in the CSF than in the serum. No significant correlation was observed between CSF and serum IL-6 levels. The present findings suggest that IL-6 of central origin is associated with the pathophysiology of schizophrenia and MDD, although confounding effect of smoking status can not be entirely excluded.     

Association of plasma IL-6 and soluble IL-6 receptor levels with the Asp358Ala polymorphism of the IL-6 receptor gene in schizophrenic patients

Recent studies indicate a role of excessive interleukin-6 (IL-6) signaling in the pathogenesis of schizophrenia. A previous study reported a significant association of schizophrenia with the IL-6 receptor (IL-6R) gene Asp358Ala polymorphism, which is known to regulate circulating IL-6 and soluble IL-6R (sIL-6R) levels in healthy subjects. To further examine the influence of the polymorphism in schizophrenic patients, we compared the plasma levels of IL-6 and sIL-6R between schizophrenic patients and healthy controls for each genotype of the Asp358Ala polymorphism. Asp358Ala genotyping and plasma IL-6 level measurements were performed in 104 patients with schizophrenia and 112 healthy controls. Of these participants, 53 schizophrenic patients and 49 controls were selected for the measurement of plasma sIL-6R levels. A two-way factorial analysis of covariance was performed with the transformed plasma levels as the dependent variable, diagnosis and genotype as independent variables, and sex and age as covariates. No significant diagnosis × genotype interaction was observed for IL-6 and sIL-6R levels. The Ala allele of Asp358Ala was significantly associated with higher levels of both IL-6 and sIL-6R. IL-6 levels were significantly elevated in schizophrenic patients compared to those in controls, whereas no significant difference in sIL-6R levels was observed between schizophrenic patients and controls. Our findings suggest that the presence of schizophrenia is associated with elevated IL-6 levels, whereas sIL-6R levels are mainly predetermined by the Asp358Ala genotype and are not associated with the disease status. Increased IL-6 levels without alterations in sIL-6R levels may result in excessive IL-6 signaling in schizophrenia.     

Elevated interleukin-6 levels in cerebrospinal fluid of vascular dementia patients

OBJECTIVES: To investigate a possible implication of inflammatory processes in the development of dementia in cerebrovascular disease. PATIENTS AND METHODS: We examined the levels of interleukin-6 (IL-6) in the cerebrospinal fluid (CSF) of patients with Alzheimer's disease (AD) (n = 26), ischemic cerebrovascular disease without dementia (CVD) (n = 11), vascular dementia (VD) (n = 11), and other neurological disorders (n = 21) using sensitive enzyme-linked immunosorbent assay. RESULTS: The CSF concentrations of IL-6 were significantly elevated in patients with VD compared with those of patients with AD or CVD. CONCLUSION: The CSF IL-6 levels are increased in patients with VD, suggesting that inflammatory mechanisms may be involved in the development of cognitive decline in some patients with cerebrovascular disease. CSF IL-6 may be a biological marker for dementia in cerebrovascular disease.     

The relationship of interleukin-2 and soluble interleukin-2 receptors to intrathecal immunoglobulin synthesis in patients with multiple sclerosis

The in vivo relationship of interleukin-2 (IL-2) to the local humoral immune response within the central nervous system (CNS) in patients with multiple sclerosis (MS) is hitherto largely unknown. Intrathecal levels of IL-2 and soluble IL-2 receptors (sIL-2R) were correlated to the local CNS synthesis of immunoglobulin G, A, D, and M isotypes in 70 patients with clinically definite MS. Levels were also determined in 19 normal control subjects to establish normal reference limits. High cerebrospinal fluid levels of IL-2 and sIL-2R were detected mainly in patients with acute relapsing-remitting MS and were significantly higher than corresponding serum levels. Intrathecal levels of IL-2 significantly correlated with local CNS synthesis of IgD and IgM, while no correlation was found with either IgG or IgA. Similarly, intrathecal sIL-2R levels significantly correlated with local CNS production of IgD and IgM, but not IgG or IgA. These findings further extend previous reports and also suggest that IL-2 and sIL-2R are involved in the early intrathecal humoral immune response in MS.     

Soluble interleukin-2 receptor and soluble CD8 in serum and cerebrospinal fluid during human immunodeficiency virus-associated neurologic disease

We have measured levels of soluble interleukin-2 receptor (sIL-2R) and soluble CD8 (sCD8) in serum and cerebrospinal fluid (CSF) of 127 human immunodeficiency virus (HIV)-seropositive and 51 HIV-seronegative individuals. Serum levels of sIL-2R and sCD8 were higher in HIV+ than in HIV- individuals. HIV+ individuals were grouped by neurological status: asymptomatic, abnormal on neuropsychological screening, HIV-related meningitis, inflammatory demyelinating polyneuropathy, opportunistic central nervous system (CNS) infections and HIV-related dementia, myelopathy or sensory neuropathy. Serum levels of sIL-2R and sCD8 were higher in all HIV+ categories compared to HIV- individuals. Patients with HIV-related meningitis had higher levels of sIL-2R and sCD8 than asymptomatic HIV+ individuals, and inflammatory polyneuropathy patients had higher levels of sCD8. CSF levels of sCD8 were higher in all categories of HIV+ than in HIV- individuals. Patients with HIV-related meningitis, inflammatory neuropathy and opportunistic infections had higher levels than asymptomatic individuals. Examination of the time course showed that serum and CSF levels of sIL-2R and sCD8 increased to very high levels during acute HIV infections. Serum levels then declined over several months to relatively stable elevated levels. By 1-2 years after HIV infection sIL-2R was relatively low in CSF, while sCD8 remained elevated with a gradual decrease over the subsequent years of follow-up.     

脑梗死患者脑脊液中白细胞介素-6检测的临床价值

目的　探讨脑梗死患者脑脊液 (CSF)中白细胞介素 6 (IL 6 )的水平及临床价值。方法　采用酶联免疫吸附双抗体夹心 (ELISA)法 ,检测 2 0例脑梗死患者及 10例对照组CSF中IL 6的水平 ,并进行动态观察。结果　脑梗死患者各时间点的CSF中IL 6的水平 ,显著高于正常对照组 ,3天内达高峰 ,发病初CSF中IL 6的水平与 3个月后的脑损伤容积明显相关 (r =0 .6 3,P <0 .0 5 )。结论　脑梗死患者CSF中IL 6的水平的测定 ,可作为判断脑损伤程度的一项早期指标。     

Increased interleukin-6 mRNA expression in blood and cerebrospinal fluid mononuclear cells in multiple sclerosis

The increased intrathecal production of immunoglobulins within the cerebrospinal fluid (CSF) compartment commonly observed in multiple sclerosis (MS) implicates participation of B cell activating factors. One effect of the cytokine interleukin (IL) -6 is induction of immunoglobulin production by activated B cells. Employing in situ hybridization (ISH) with synthetic oligonucleotide probes, we measured numbers of IL-6 mRNA-expressing mononuclear cells (MNC) in blood and CSF from patients with MS, aseptic meningo-encephalitis (AM), and in blood from patients with other neurological diseases (OND) and healthy subjects. Numbers of IL-6 mRNA-expressing MNC were elevated in blood (mean frequency 1 per 33000 MNC) and even further enriched in the CSF (1 per 10000 MNC) of MS patients, and to a similar extent in AM patients' blood. Cultivation in the presence of myelin basic protein and proteolipid protein revealed strong augmentation of IL-6 mRNA-positive cells in MS but not in OND. The results suggest that IL-6 is one of several cytokines which are upregulated in MS, in particular locally in the CSF. A role of IL-6 in MS, whether disease-promoting or protective, remains unclear.     

Genetic and environmental determinants of population variation in interleukin-6, its soluble receptor and C-reactive protein: Insights from identical and fraternal twins

Interleukin-6 and C-reactive protein are commonly assessed biomarkers linked to illness, obesity, and stressful life events. However, relatively little is known about their heritability. By comparing Caucasian twins from the Midlife in the US project (MIDUS), we estimated the heritability of IL-6, its soluble receptor, and CRP. Based on the hypothesis that adiposity might contribute more to IL-6 than to sIL-6r, we fit heritability models quantifying the extent to which each reflected genetic and environmental factors shared with obesity. Genetic influences on IL-6 and its receptor proved to be distinct. Further, the appearance of a heritable basis for IL-6 was mediated largely via shared paths with obesity. Supporting this conclusion, we confirmed that when unrelated adult controls are carefully matched to twin participants on BMI, age, gender and socioeconomic indices, their IL-6 is similar to the corresponding twins. In contrast, the effect of BMI on CRP was split between shared genetics and environmental influences. In conclusion, IL-6 is strongly affected by factors associated with obesity accounting for its lability and responsiveness to diet, life style and contemporaneous events.     

Neurochemical markers in the cerebrospinal fluid of patients with Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis and normal controls

Summary Several neurotransmitter markers were investigated in the cerebrospinal fluid (CSF) from patients with Alzheimer's disease (AD) (n=27), Parkinson's disease (PD) (n=35) and ALS (n=26) and from control subjects (n=34) to compare the possible alterations in the biochemical profiles of these different neurodegenerative diseases. The main proportion of the patients represented an early phase of the illness at the time of the diagnosis. Correlations of the degree of dementia and the stage of the disease with CSF measures were evaluated. The CSF levels of somatostatin like-immunoreactivity (SLI) were significantly reduced in AD patients when compared with those of normals and ALS patients. The CSF concentrations of homovanillic acid (HVA) were significantly decreased for PD patients and the decrease focused on the nondemented patients. A trend of decreasing HVA values towards the most advanced stage of Parkinson's disease assessed by Webster's scale was also displayed. The content of 3-methoxy-4-hydroxyphenylglycol (MHPG) in the CSF was higher for ALS patients than for other groups. The lowest 5-hydroxy-indoleacetic acid (5HIAA) levels were observed in the PD group and the lowest acetylcholinesterase (AChE) activities were found in the PD patients with the most severe disease. Changes in CSF measures were too subtle to be beneficial for diagnostic purposes, but adequate for reflecting the different neurochemical profiles of these three degenerative neurological disorders.     

Increased cerebrospinal fluid cAMP levels in Alzheimer's disease

Since increasing evidence suggests that upregulation of the cAMP-second messenger system may be implicated in Alzheimer's disease neurodegeneration, we have compared the cAMP and cGMP levels in cerebrospinal fluid (CSF) from patients with dementia of the Alzheimer type (DAT, n=10) with those from nondemented age-matched controls (n=10). Our results show that cAMP levels, but not cGMP, are significantly (p<0.01) elevated in CSF from patients with DAT compared to those from nondemented controls. Moreover, a linear regression analysis demonstrated a significant correlation (r=0.62; p<0.01) between cAMP and tau protein levels in CSF when controls and patients with DAT were studied together. These results suggest that upregulation of cAMP-signaling pathway is implicated in Alzheimer's disease physiopathology.     

Cerebrospinal fluid levels of soluble tumour necrosis factor receptor in acute encephalitis

Soluble tumour necrosis factor receptor (sTNF-R) inhibits the action of TNF-. The level of sTNFR reflects the true biological activity of TNF-. We investigated whether sTNF-R in cerebrospinal fluid (CSF) and serum increases during the acute stage in patients with acute encephalitis by measuring p60 sTNF-R using a sandwich enzyme immunoassay. The levels of sTNF-R were significantly higher in the CSF and serum of children with acute encephalitis than in those of control subjects. The patients with acute encephalitis who died or had severe neurological sequelae had higher CSF sTNF-R levels than those who survived. There were no significant differences in the serum sTNF-R, serum C-reactive protein and CSF protein levels, and CSF cell counts between the two groups. The sTNF-R levels of 4.0 ng/ml or higher identified patients with acute encephalitis who had neurological sequelae with a sensitivity of 100% (8/8), a specificity of 100% (8/8), and a predictive value of 100% (8/8). The 95% confidence interval for these three values is 63–100%. Our findings suggest that the CSF level of sTNF-R during the acute stage of encephalitis is important for predicting neurological sequelae.     

Nitric oxide metabolites and interleukin-6 in cerebrospinal fluid from multiple sclerosis patients

Interleukin-6 (IL-6) and nitric oxide (NO) are implicated in the pathology of multiple sclerosis (MS). We have investigated the levels of these mediators in the cerebrospinal fluid (CSF) from 50 patients with MS and 23 control subjects. Mean CSF IL-6 level was higher in the total MS group in comparison with controls, but not significantly, whilst the difference between patients with stable MS and controls reached the level of statistical significance. Mean CSF nitrite/nitrate level was significantly higher in the total MS group compared with the control group, as well as in active MS patients versus controls. There was significant difference neither in the mean CSF IL-6 nor in nitrite/nitrate levels between active and stable MS patients. Interestingly, we observed a significant negative correlation between IL-6 and nitrite/nitrate levels in the CSF in the total MS group. Such a trend existed in both subgroups with active and stable MS, but without reaching the level of statistical significance. Our data further support the involvement of IL-6 and NO in ongoing pathological processes in MS, suggesting their potential interplay within the central nervous system in this disease.     

Oligoclonal immunoglobulin bands in cerebrospinal fluid of patients with Alzheimer''s disease and vascular dementia

We examined serum and cerebrospinal fluid (CSF) of 16 patients with Alzheimer's disease (AD), 28 patients with vascular dementia (VD), their age-matched controls and multiple sclerosis (MS) patients in order to evaluate the humoral immune response within the central nervous system both quantitatively and qualitatively. Intra-blood-brain barrier (BBB) protein synthesis was calculated by CSF IgG index. The presence of oligoclonal banding (OCB) was investigated with agarose isoelectric focusing (IEF) followed by immunoblotting with antihuman IgG. No patient with AD and only 4 patients with VD had slightly elevated IgG indexes, and no statistically significant differences in the indexes were found between the two groups. No bands were found in the CSF of AD patients but 3 VD patients had OCB in both serum and CSF. One VD patient had bands in serum but no bands in CSF. No kappa or lambda free light chains were found in those demented patients with demonstrable bands in the CSF and serum. No OCB were found in control sera and CSF. For comparison, the majority of patients with MS had OCB in CSF. Thus, no consistent increase of intrathecal protein synthesis was found in patients with AD and VD. Methodological differences explain at least part of the conflicting results published earlier.     

Soluble interleukin-1 receptor type II levels are elevated in cerebrospinal fluid in Alzheimer's disease patients

Evidence from epidemiological, clinical and experimental studies favour the hypothesis that inflammatory events are part of the neuropathology in Alzheimer's disease. Proinflammatory cytokines such as interleukin-1 (IL-1), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) have been found in activated microglia in the vicinity of amyloid plaques in Alzheimer's disease brain. In the present study, the levels of soluble IL-1 receptor type II (sIL-1R type II), IL-1 receptor antagonist (IL-1ra), IL-1beta, IL-6 and TNF-alpha were analyzed in cerebrospinal fluid (CSF) samples from Alzheimer's disease patients and control subjects. The levels of sIL-1R type II were significantly higher in CSF from Alzheimer's disease patients than in CSF samples from control subjects (38.5+/-8 pg/ml (mean+/-S.E.M.) vs. 7.9+/-4 pg/ml, p<0.05). Measurements of the proinflammatory cytokines IL-6 and TNF-alpha showed no significant difference between the two groups, and the levels of IL-1beta and IL-1ra in the present material were too low to permit detection. The increased levels of sIL-1R type II may reflect a compensatory mechanism to balance an increased release of IL-1 receptor agonists in the Alzheimer's disease brain.     

Decreased cerebrospinal fluid levels of neutral and basic amino acids in patients with Parkinson''s disease

We measured the CSF levels of 21, and the plasma levels of 26, amino acids in 31 patients with Parkinson's disease (PD) and in 45 matched controls. We used an ion-exchange chromatography method. When compared to controls, PD patients had lower CSF levels of taurine, alanine, valine, leucine, isoleucine, ethanolamine, citrulline, ornithine, lysine, histidine, arginine, and alpha-aminobutyric acid. PD patients not treated with levodopa or with dopamine agonists had higher CSF tyrosine and phenylalanine levels than those not treated with these drugs and also than controls. PD patients had higher plasma levels of phosphoserine, threonine, methionine, tyrosine, sarcosine and -aminoadipic acid, and lower plasma levels of valine, leucine, and tryptophan, than controls. The CSF/plasma ratio of many of these amino acids was significantly lower in PD patients than those of controls, suggesting that PD patients might have a dysfunction in the transport of neutral and basic amino acids across the blood–brain barrier.     

四连接素在帕金森病脑脊液中的表达变化

目的探讨脑脊液中可能的帕金森病（PD）生物标记物。方法采用荧光差异凝胶电泳（DIGE）技术分离并筛选PD患者和正常对照者脑脊液中差异表达蛋白质,用基质辅助激光解吸电离飞行时间质谱（MALDl-TOFMS）技术进行鉴定并分析,应用Westernblotting进行验证。结果DIGE发现20个明显的差异蛋白点,共鉴定出8个蛋白质。DIGE分析和Westernblotting验证均显示蛋白四连接素在PD患者脑脊液中发生显著下调。结论四连接素可能参与了PD发生,有可能成为PD的生物标记物。