Vitamin B12 levels in serum and cerebrospinal fluid of people with Alzheimer's disease

Vitamin B12 levels in the serum and the cerebrospinal fluid (CSF) were compared between patients with Alzheimer's disease (AD) and senile dementia of Alzheimer's type (SDAT) (AD group) and patients with multi-infarct dementia (MID group). The B12 levels in the serum and the CSF were 742 +/- 359 pg/ml and 28 +/- 7 pg/ml (mean +/- SD), respectively, in the AD group, and 962 +/- 254 pg/ml and 50 +/- 26 pg/ml, respectively, in the MID group. CSF B12 levels were significantly lower in the AD group than in the MID group, whereas the serum levels were not different. At the same time, the serum levels of almost all patients were within the normal range, whereas the CSF levels were 25 pg/ml or lower in 10 of 12 AD patients. Therefore, this low level in the CSF is considered to be a characteristic finding in the AD group.     

The soluble 60-kDa tumour necrosis factor receptor: no difference found between patients with relapsing-remitting multiple sclerosis and controls: increasing levels are associated with the recovery from Guillain-Barré syndrome

We determined serum and cerebrospinal fluid (CSF) levels of the soluble 60-kDa tumour necrosis factor (TNF) receptor (sTNF-R p60) in 50 patients with relapsing-remitting multiple sclerosis (MS) and in 18 patients with Guillain-Barré syndrome (GBS). Neither in serum nor in CSF samples was there a statistically significant difference between mean receptor concentrations of patients with MS (serum: 1064, SD 262 pg/ml; CSF: 555, SD 130 pg/ml), with other noninflammatory neurological diseases (serum: 1008, SD 248 pg/ml; CSF: 530, SD 112 pg/ml) and with healthy control subjects (serum: 918, SD 180 pg/ml). In order to determine disease activity, magnetic resonance imaging (MRI) of the brain was performed in all MS patients. The mean sTNF-R p60 levels of patients who showed gadolinium DTPA enhancement on MRI were not different from those without enhancement (1034, SD 274 pg/ml vs 1099, SD 248 pg/ml in serum samples and 546, SD 109 pg/ml vs 565, SD 152 pg/ml in CSF samples). In GBS, the sTNF-R p60 levels of serum and CSF samples were significantly higher than in MS and all control groups except for the group with viral meningitis (VM) (GBS: 1544, SD 834 pg/ml in serum, 882, SD 147 pg/ml in CSF; VM: 1518, SD 375 pg/ml in serum, 1131, SD 611 pg/ml in CSF; P < 0.001 for serum samples and P < 0.005 for CSF samples). Serial serum sTNF-R p60 measurements in 13 patients with GBS showed an increase in receptor levels parallel with the recovery from the disease (1276, SD 374 pg/ml at the time of disease onset, 1554, SD 482 pg/ml 14–24 days later and 1787, SD 525 pg/ml after 28–32 days). From our results and the conflicting data of previous studies, we could not agree with the suggestion that the assessment of sTNF-R p60 in MS patients is a useful marker for disease activity. In GBS, subsequently increasing sTNF-R p60 levels are associated with recovery from the disease. It remains to be shown whether they might represent a relevant pathogenetic factor during this stage of GBS. Received: 31 October 1997 Received in revised form: 26 January 1998 Accepted: 10 February 1998     

Cerebrospinal fluid protein tau levels in the differential diagnosis of Alzheimer's disease

Tau protein concentration in cerebrospinal fluid was determined in 55 patients with Alzheimer's disease (AD), 18 patients with vascular dementia (VD), 19 patients with dementia caused by other disorders and 14 patients with major depression. Significantly (p < 0.05) elevated protein tau concentrations were found in AD patients (564.5 +/- 275.5 pg/ml) compared to all other patient groups (VD: 406.5 +/- 263.9 pg/ml; other dementia: 275.0 +/- 135.4 pg/ml; depression: 212.9 +/- 115.6 pg/ml). However, tau levels in AD patients covered a broad range (163.2 pg/ml-1200 pg/ml). AD patients with tau levels below the 25%-percentile of the distribution (among them a high percentage of patients with presenile onset) showed tau levels similar to those of the patients with late life depression. No significant correlations between tau levels and clinical variables such as severity of dementia, age, age of onset, duration of illness, and cerebral changes as assessed by volumetric magnetic resonance imaging could be demonstrated. Similarly, we could not find an influence of either APO-E genotype or psychotropic medication on the tau levels in AD patients. In accordance with other studies our results confirm elevated tau levels in AD compared to elderly not demented control subjects. Comparing groups, this finding applies as well with respect to VD and other dementing disorders. However, elevated tau levels cannot be detected in a subgroup of AD patients. This finding needs to be further investigated in future studies.     

BDNF serum and CSF concentrations in Alzheimer's disease, normal pressure hydrocephalus and healthy controls

Alzheimer's disease (AD) and normal pressure hydrocephalus (NPH) are common forms of dementia in the elderly. Recent findings have suggested an involvement of brain-derived neurotrophic factor (BDNF) in the pathogenesis of AD. BDNF is an endogenous protein involved in the maintenance of neuronal function, synaptic plasticity and structural integrity in the adult brain. BDNF serum and cerebrospinal fluid (CSF) concentrations were assessed by a sensitive ELISA in 27 AD patients in comparison to 9 NPH patients and 28 age-matched healthy controls (10 CSF samples). We found a significant decrease of BDNF serum concentration in AD (18.6ng/ml) and NPH patients (18.1ng/ml) as compared to healthy controls (21.3ng/ml; p=0.041/p=0.017). BDNF serum concentrations did not correlate with CSF levels, age or MMSE scores both in AD and NPH patients. In unconcentrated CSF samples, BDNF could be detected in AD patients in 8/27 cases (29.6%; mean of 4.6pg/ml), in NPH patients in 1/9 cases (11.1%; mean of 6.4pg/ml) and in the control subjects in 5/10 cases (50%; mean of 1.6pg/ml) with no significant differences as regards mean concentration and frequency of detectable BDNF in CSF. The decrease of BDNF serum levels in AD and NPH may reflect a lack of trophic support and thus contribute to progressive degeneration in both diseases. In contrast to serum, CSF seems to be no useful source to determine BDNF in AD or NPH because of too low concentrations. Further examinations have to follow to elucidate the potential sources and the meaning of reduced BDNF levels in the blood in AD and NPH.     

Behavioural and psychological symptoms of Alzheimer type dementia are not correlated with plasma homocysteine concentration

BACKGROUND/AIMS: Vitamin B12 and folate deficiencies have been associated with cognitive impairment and various psychiatric symptoms but not specifically with behavioural and psychological symptoms of dementia (BPSD). A limitation of previous studies in dementia was lack of concurrent homocysteine measurement especially as it may provide a better indicator of tissue activities of these vitamins. This study was designed to clarify whether a relationship exists between plasma homocysteine concentration and BPSD. METHODS: Plasma homocysteine, serum vitamin B12 and folate were measured in 23 Alzheimer's disease (AD) patients with BPSD and 27 AD patients without BPSD as determined through the use of the Neuropsychiatric Inventory (NPI). Blood levels of measured substances were also correlated with individual NPI scores and with cumulative NPI scores for different cluster of symptoms. RESULTS: There was no significant difference (p = 0.956) in the mean plasma homocysteine levels between AD patients with BPSD (17.48 micromol/l) and AD patients without BPSD (17.34 micromol/l). Similarly, there was no significant difference between the two groups in the mean serum B12 (382.61 and 391.60 pg/ml, respectively) and folate (7.95 and 10.02 ng/ml, respectively). Mean levels for both vitamins were well within the laboratory reference range. Neither individual nor cluster NPI scores correlated significantly with plasma homocysteine. CONCLUSION: This study shows for the first time that BPSD are not associated with hyperhomocysteinaemia in Alzheimer dementia. Although previous studies have identified homocysteine as an independent risk factor in AD, the results reported here do not lend weight to an aetiological role for homocysteine specifically in BPSD.     

A lzheimer病患者血清IL-2、sIL-2R水平的研究

目的 :Alzheimer病 (AD)是由多种病因引起的涉及多种病理机制和出现多种病理表现的多因素性疾病。近年来研究发现 AD患者血清中细胞因子水平增高以及皮质、海马内神经炎性斑数量增加 ,表明免疫炎症机制在 AD的发生、发展中起重要作用。本研究拟通过对 AD患者血清 IL - 2、 s IL - 2 R水平的检测 ,来探讨其在 AD慢性炎症病理过程中的作用。方法 :采用双抗体酶联免疫吸附试验 (EL ISA) ,检测 10例 AD患者血清 IL 2及 s IL 2 R水平 ,并与血管性痴呆 (VD)组及正常对照组做了比较。结果 :AD组血清中 IL- 2水平为 35 2± 33.4pg/ ml,明显高于 VD组 (2 83.6± 6 2 .9pg/ ml)和正常对照组 (2 5 8.5± 49.1pg/ ml) ,差异显著 (P<0 .0 0 5 ) ;AD组 s IL - 2 R水平为 81± 37.3pmol/ L ,明显高于VD组 (5 4.1± 30 .9pmol/ L )和正常对照组 (48.3± 18.3pmol/ L ) ,差异显著 (P<0 .0 5 )。结论 :说明 AD患者脑内免疫细胞被激活 ,IL- 2、s IL- 2 R参与了 AD的慢性炎症改变过程。血清 IL- 2和 s IL- 2 R可作为检测 AD外周血的免疫标记物。     

Vascular endothelial growth factor plasma levels are significantly elevated in patients with cerebral arteriovenous malformations

BACKGROUND: Since growth and de novo generation of cerebrovascular malformations were demonstrated, a strictly congenital model cannot be further supported as unique factor in the pathogenesis of cerebral arteriovenous malformations (AVMs). Vascular endothelial growth factor (VEGF) has previously been demonstrated to be highly expressed in AVMs by immunohistochemical methods. However, systemic VEGF levels have not been analysed previously. This study aimed to investigate VEGF plasma concentrations as a possible plasma marker for neovascularization in patients with cerebral AVMs compared to healthy controls. METHODS: The study included 17 patients with cerebral AVMs and 40 healthy controls. VEGF plasma concentrations were measured by a specific enzyme immuno-assay. RESULTS: VEGF plasma concentrations were significantly higher in patients with cerebral AVMs (mean 140.9 pg/ml, SD 148.5 pg/ml and median 63.0 pg/ml) compared to a healthy control group (mean 44.7 pg/ml, SD 36.4 pg/ml and median 35.0 pg/ml), p = 0.0003. CONCLUSIONS: Our findings suggest that VEGF plasma concentrations might play a role in the pathogenesis of cerebral AVMs. Further studies are necessary and would contribute to an improved understanding of the pathogenesis of cerebral AVMs.     

Decreased plasma and cerebrospinal fluid levels of stem cell factor in patients with early Alzheimer's disease

Alzheimer's disease (AD) is characterized by massive neuronal cell loss in the brain. Stem cell factor (SCF) is a hematopoietic growth factor (HGF) that promotes neuroprotective effects and supports neurogenesis in the brain. In the present study, we found significantly lower SCF plasma levels in 30 early AD patients (908.5 +/- 181.7 pg/ml) in comparison with 30 age-matched healthy controls (1058.3 +/- 221.5 pg/ml; p = 0.006). SCF plasma levels in AD patients showed a significant inverse correlation with dementia severity as measured by ADAS-Cog (r = -0.289; p = 0.037). AD patients showed significantly lower SCF levels in cerebrospinal fluid (CSF) (131.60 +/- 43.03 pg/ml) in comparison with 15 age- and gender-matched patients with other non-inflammatory neurological disease (NIND) (166.03 +/- 42.5 pg/ml; p = 0.017). In addition, we found significant positive correlations between SCF and CXCL12 (also known as SDF-1) plasma levels in healthy controls (r = 0.341; p = 0.008) and between SCF and CXCL12 CSF levels in AD patients (r = 0.487; p < 0.001). In conclusion, decreased SCF plasma and CSF levels in early AD patients may contribute to a deficient hematopoietic brain support with putative pathogenic and clinical relevance. Further studies are needed to examine whether a manipulation of HGFs such as SCF could be a promising new therapeutic strategy for AD.     

Vascular endothelial growth factor (VEGF) is increased in serum, but not in cerebrospinal fluid in HIV associated CNS diseases

Vascular endothelial growth factor (VEGF) is a potent angiogenic and mitogenic peptide, which also induces several mediators that may play a role in HIV induced CNS damage. VEGF levels were determined in cerebrospinal fluid (CSF) and serum samples from patients with (n = 8) and without (n = 19) directly HIV associated CNS disorders and HIV negative control patients (n = 18). VEGF serum but not CSF levels were significantly increased in HIV infected patients with (381.1 (78.9) pg/ml) HIV associated CNS diseases compared with those without (120.8 (13.1) pg/ml) and HIV negative control patients (133.1(14.8) pg/ml). Serum samples from patients with untreated HIV associated encephalopathy (HIVE, n = 3) contained the highest VEGF levels (583.9 (71.5) pg/ml). In two patients VEGF serum levels were reduced during antiretroviral therapy. However, regardless of effective viral suppression, patients with HIVE still had higher levels compared with HIV infected patients without HIVE. A relevant increase of serum VEGF was not observed in patients without HIVE though high HI viral load. We conclude that HIVE is associated with increased serum VEGF levels. Further studies are warranted to elucidate the role of VEGF in HIVE.     

Vascular endothelial growth factor (VEGF) is elevated in brain tumor cysts and correlates with tumor progression

Vascular endothelial growth factor (VEGF), a key regulatory protein in neoangiogenesis, is strongly expressed in a variety of primary brain tumors, particularly malignant gliomas. In previous studies, high levels of VEGF were also reported in tumor cysts of glioblastomas. Using an ELISA method we measured the concentration of VEGF in matched samples of aspiration fluid from tumor cysts and serum. Samples were collected from 14 patients with primary brain tumors of various histology (six glioblastomas, one protoplasmatic astrocytoma, two pilocytic astrocytomas, one ependymoma, one meningioma, and three craniopharyngiomas) and two patients with solitary cystic brain metastases from adenocarcinomas of the lung. Aspiration fluids of tumor cysts from all patients revealed high VEGF levels ranging between 882 and 1,263,000 pg/ml, which were 2 to more than 2,000 times higher than the corresponding serum levels. Maximum VEGF levels were detectable in cyst fluids from recurrent glioblastoma. Serum VEGF levels ranged between 125 and 716 pg/ml and did not differ from serum levels in 145 healthy volunteers. In a single patient with metastatic lung cancer the concentration of VEGF in serum and cyst fluid was determined during disease progression. During 60 days of follow-up VEGF concentrations in the cyst fluid collected by puncture of an Ommaya reservoir increased 650-fold, while serum levels remained rather constant. These findings indicate that immunoreactive VEGF is produced at the tumor site and abundantly released into the cyst fluid of primary and metastatic brain tumors. Interestingly, this abundant local release is not reflected in serum VEGF levels, even in the case of very high VEGF concentrations in tumor cysts. Thus, VEGF may be biologically relevant for the formation of tumor cysts in brain tumors and correlates with local disease progression. Received: 29 March 1999 / Revised / Accepted: 13 October 1999