Low IL-8 is associated with anxiety in suicidal patients: genetic variation and decreased protein levels

OBJECTIVE

Recent studies indicate that inflammation may play a role in the pathophysiology of suicidality. Interleukin-8 (IL-8) is a chemokine that in addition to its function in the immune system also exert neuroprotective properties. The involvement of this chemokine in neuropsychiatric conditions is incompletely known.

METHOD

We measured plasma and cerebrospinal fluid (CSF) IL-8, as well as the genotype frequency of a single nucleotide polymorphism (-251A/T, rs4073) in the promoter region of the IL8 gene, in suicide attempters (n=206) and healthy controls (n=578).

RESULTS

Plasma and CSF levels of IL-8 were significantly lower in suicide attempters with anxiety than in healthy controls. IL-8 in both plasma and CSF correlated negatively with symptoms of anxiety. Compared with the population-based cohort, the IL-8-251T allele was more prevalent among female suicide attempters. Furthermore, suicide attempters carrying this allele showed more severe anxiety. This correlative study warrants further mechanistic studies on the effects of IL-8 in the central nervous system.

CONCLUSION

We suggest that IL-8 might be involved in the biological mechanisms mediating resilience to anxiety. Thus, our findings highlight the chemokine IL-8 as a potential target for future development of anti-anxiety treatments and suicide prevention.

Regional differences in effects of APOE ε4 on cognitive impairment in non-demented subjects

BACKGROUND

The APOE ε4 allele is a risk factor for Alzheimer's disease (AD). APOE ε4 is common in non-demented subjects with cognitive impairment. In both healthy people and people with AD, its prevalence has a north-south gradient across Europe. In the present study, we investigated whether the relation between the APOE ε4 allele and cognitive impairment varied across Northern, Middle and Southern Europe. We also investigated whether a north-south gradient existed in subjects with subjective cognitive impairment (SCI), amnestic mild cognitive impairment (MCI) and non-amnestic MCI.

METHODS

Data from 16 centers across Europe were analyzed.

RESULTS

A north-south gradient in APOE ε4 prevalence existed in the total sample (62.7% for APOE ε4 carriers in the northern region, 42.1% in the middle region, and 31.5% in the southern region) and in subjects with SCI and amnestic MCI separately. Only in Middle Europe was the APOE ε4 allele significantly associated with poor performance on tests of delayed recall and learning, as well as with the amnestic subtype of MCI.

CONCLUSION

The APOE ε4 allele frequencies in subjects with SCI and amnestic MCI have a north-south gradient. The relation between the APOE ε4 allele and cognition is region dependent.

Age and diagnostic performance of Alzheimer disease CSF biomarkers

OBJECTIVES

Core CSF changes in Alzheimer disease (AD) are decreased amyloid β(1-42), increased total tau, and increased phospho-tau, probably indicating amyloid plaque accumulation, axonal degeneration, and tangle pathology, respectively. These biomarkers identify AD already at the predementia stage, but their diagnostic performance might be affected by age-dependent increase of AD-type brain pathology in cognitively unaffected elderly.

METHODS

We investigated effects of age on the diagnostic performance of CSF biomarkers in a uniquely large multicenter study population, including a cross-sectional cohort of 529 patients with AD dementia (median age 71, range 43-89 years) and 304 controls (67, 44-91 years), and a longitudinal cohort of 750 subjects without dementia with mild cognitive impairment (69, 43-89 years) followed for at least 2 years, or until dementia diagnosis.

RESULTS

The specificities for subjects without AD and the areas under the receiver operating characteristics curves decreased with age. However, the positive predictive value for a combination of biomarkers remained stable, while the negative predictive value decreased only slightly in old subjects, as an effect of the high AD prevalence in older ages.

CONCLUSION

Although the diagnostic accuracies for AD decreased with age, the predictive values for a combination of biomarkers remained essentially stable. The findings highlight biomarker variability across ages, but support the use of CSF biomarkers for AD even in older populations.

Changes in CSF acetyl- and butyrylcholinesterase activity after long-term treatment with AChE inhibitors in Alzheimer's disease

OBJECTIVES

  To measure cerebrospinal fluid (CSF) activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in patients with Alzheimer's disease (AD) participating in randomized clinical trials from three European centers, before and after long-term treatment with different AChE inhibitors (AChEIs).

MATERIALS AND METHODS

  Of the 144 patients included in the study, 104 were treated with donepezil, 15 with galantamine, 16 with rivastigmine, and nine with placebo. CSF AChE and BChE activities were measured at baseline and after 1- year treatment.

RESULTS

Donepezil and galantamine groups showed a significant increase in CSF AChE activity at follow-up, while no changes for BChE activity were observed; in donepezil group, a positive correlation between plasma concentration and AChE activity was documented. Conversely, in rivastigmine group, a decrease in CSF activity of both enzymes was observed. CSF AChE and BChE activities were not correlated with the clinical outcome in any group considered. CSF biomarkers did not show any change after treatment.

CONCLUSIONS

  AChEIs differently influence the activity of target enzymes in CSF independent of their pharmacodynamic effects.

Efficacy of memantine in PDD and DLB: an extension study including washout and open-label treatment

OBJECTIVE

This 30-week extension trial was a continuation of the first double-blind randomized controlled trial (RCT) to study memantine in dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). The objective was to evaluate the presence of recurrence of symptoms upon drug withdrawal. Furthermore, the aim was to explore washout dynamics in order to inform clinical practice.

METHODS

Patients were enrolled from psychiatric, memory and neurological outpatient clinics in Norway, Sweden and the UK. The trial comprised a 4-week washout period and a 26-week open-label treatment period. Outcome measures were presence of recurrence of symptom upon drug withdrawal, Clinical Global Impression of Change (CGIC) and modified motor Unified Parkinson's Disease Rating Scale (UPDRS).

RESULTS

recurrence of symptoms occurred more frequently (p=0.04) in patients receiving memantine (58%) than in patients receiving placebo (25%). There was a significant global deterioration (p=0.0003) during washout within the memantine group as measured by CGIC. The patients seemed to recover during the open-label treatment, however these findings were non-significant.

CONCLUSIONS

The findings inform clinical practice that any possible memantine-associated benefits might be rapidly lost after drug withdrawal. The magnitude of deterioration suggests a symptomatic rather than a disease-modifying effect of the drug. Open-label results should merely be considered inspiration for future trials.

The cognitive profile and CSF biomarkers in dementia with Lewy bodies and Parkinson's disease dementia

OBJECTIVE

Dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD) may be viewed as different points on a continuum reflecting the regional burden and distribution of pathology. An important clinical consideration is overlapping Alzheimer's disease (AD) pathology, since it has been reported that associated AD pathology in DLB shortens survival and leads to a more rapid cognitive decline. We aimed to investigate cerebrospinal fluid (CSF) biomarkers and the associated cognitive profile in DLB and PDD.

METHODS

Clinically diagnosed DLB (n=47) and PDD (n=17) patients from a clinical follow-up programme were investigated. All performed mini mental state examination (MMSE) and went through lumbar puncture at baseline. CSF concentrations of total τ (T-τ), τ phosphorylated at threonine 181 (P-τ(181) ) and the 42 amino acid isoform of amyloid β, Aβ42 were determined.

RESULTS

We found significant differences in T-τ and Aβ42, with a higher level of T-τ and a lower level of Aβ42 in DLB compared to PDD. The combination of T-τ with Aβ42 showed better discrimination between DLB and PDD than either of the measures alone. In DLB, a CSF profile more like the one seen in AD was significantly correlated with worse performance on the orientation and memory of the MMSE.

CONCLUSION

The correlation suggests a possible link between a higher degree of AD pathology and a profile of more temporal disabilities on cognitive tests in DLB. This might aid in identifying a subgroup of patients with a greater burden of AD pathology in a clinical setting and could have important implications for prognosis.

Computerized cognition assessment during acetylcholinesterase inhibitor treatment in Alzheimer's disease

OBJECTIVES

Alzheimer's disease assessment scale-cognitive subscale (ADAS-Cog) has become a standard clinical trials outcome for cognition, but has been recognized as deficient in areas including coverage of cognitive domains, sensitivity and standardization. Computerized test batteries may address some of these issues. The cognitive drug research computerized assessment (CDR) system is validated in Alzheimer's disease (AD). This study was designed to further evaluate validity in relation to ADAS-Cog, mini mental state examination (MMSE) and cerebrospinal fluid (CSF) biomarkers and psychometric properties, in a population of Alzheimer's patients on stable anticholinesterase treatment.

MATERIALS AND METHODS

Patients completed cognition assessments, CSF and blood sampling at baseline and 6 months later. Data for 65 patients were evaluated.

RESULTS

The CDR system demonstrated good psychometric properties in this population. Measures of psychomotor speed showed possible sensitivity to decline over 6 months.

CONCLUSIONS

There are a number of methodological problems with current cognition assessment methodology for clinical trials. Computerized measures and in particular millisecond reaction time measures, may address many of these issues.

The stability of AQT processing speed, ADAS-Cog and MMSE during acetylcholinesterase inhibitor treatment in Alzheimer's disease

OBJECTIVES

To explore the longitudinal stability of measures of cognition during treatment with acetylcholinesterase inhibitors (AchEI) in patients with Alzheimer's disease (AD).

MATERIALS AND METHODS

Cognitive status was measured in a cohort of 60 patients at 6 months after initiation of treatment with AchEI (baseline) and after an additional 6 months of treatment (endpoint). A Quick Test of Cognitive Speed (AQT), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), and MMSE were administered concurrently.

RESULTS

Correlations (rho) between age and AQT processing speed were non-significant, but were significant for ADAS-Cog and Mini Mental State Examination (MMSE). AQT and ADAS-Cog means did not differ significantly between baseline and endpoint. There was a small, significant reduction in MMSE point scores. Measures of stability (Spearman's rho) were moderate-to-high for all tests. Means for subgroups did not differ as a function of medication type.

CONCLUSIONS

AQT processing speed, ADAS-Cog, and MMSE measures proved stable during the second 6 months of treatment with AChEI.

White matter hyperintensities and medial temporal lobe atrophy in clinical subtypes of mild cognitive impairment: the DESCRIPA study

BACKGROUND

Clinical subtypes of mild cognitive impairment (MCI) may represent different underlying aetiologies.

METHODS

This European, multicentre, memory clinic based study (DESCRIPA) of non-demented subjects investigated whether MCI subtypes have different brain correlates on MRI and whether the relation between subtypes and brain pathology is modified by age. Using visual rating scales, medial temporal lobe atrophy (MTA) (0-4) and white matter hyperintensities (WMH) (0-30) were assessed.

RESULTS

Severity of MTA differed between MCI subtypes (p<0.001), increasing from a mean of 0.8 (SD 0.7) in subjective complaints (n = 77) to 1.3 (0.8) in non-amnestic MCI (n = 93), and from 1.4 (0.9) in single domain amnestic MCI (n = 70) to 1.7 (0.9) in multiple domain amnestic MCI (n = 89). The association between MCI subtype and MTA was modified by age and mainly present in subjects >70 years of age. Severity of WMH did not differ between MCI subtypes (p = 0.21). However, the combination of MTA and WMH differed between MCI subtypes (p = 0.02)

CONCLUSION

We conclude that MCI subtypes may have different brain substrates, especially in older subjects. Isolated MTA was mainly associated with amnestic MCI subtypes, suggesting AD as the underlying cause. In non-amnestic MCI, the relatively higher prevalence of MTA in combination with WMH may suggest a different pathophysiological origin.

Medial temporal lobe atrophy increases the specificity of cerebrospinal fluid biomarkers in Alzheimer disease with minor cerebrovascular changes

BACKGROUND

Although cerebrospinal fluid (CSF) biomarkers and medial temporal lobe atrophy (MTA) contribute to the diagnosis of Alzheimer disease (AD), they may not be specific. Relatively little is known about how they correlate with each other.

PURPOSE

To identify the validity of the radiological linear measurements of brain atrophy in AD diagnosis by examining the correlation with CSF biomarkers and by examining if specificity could be improved in classification of AD from controls, when the linear measurements are combined with the CSF biomarkers.

MATERIAL AND METHODS

59 controls (20 male/39 female, age 73+/-8 years), 162 pure AD patients (49/113, 74+/-7 years), and 86 AD patients with minor cerebrovascular changes (CVC) (31/55, 77+/-5 years), aged between 52 and 94 years, were recruited from the Malmo Alzheimer Study. AD patients were subgrouped into "pure AD" and "AD + CVC" in order to clarify the possible influence of CVC on atrophy or CSF biomarkers in AD patients. Abeta42, T-tau, and P-tau in CSF were examined. Computed tomography (CT) linear measurements were performed, which included temporal horn ratio and suprasellar cistern ratio that reflect MTA.

RESULTS

Compared with the 14 significant correlations between the CT measurements and three CSF biomarkers in the pure AD group, there was only one significant correlation in the AD + CVC group and one in the control group. In particular, P-tau correlates with temporal horn ratio only in pure AD. When the CT measurements were added with CSF biomarkers as independent variables in discriminant analysis, the percentage of correct classification of AD + CVC from controls increased from 79.5% (only CSF biomarkers) to 84.6% (combined CT measurements with CSF biomarkers). However, little was changed in the pure AD group.

CONCLUSION

P-tau correlates with the linear CT measure of MTA only in pure AD without CVC. Combined with the measure of MTA, the specificity of CSF biomarkers can be increased, but only in AD + CVC. The linear measurements of MTA are of value in AD diagnosis.

Can CSF biomarkers or pre-treatment progression rate predict response to cholinesterase inhibitor treatment in Alzheimer's disease?

OBJECTIVE

The main objective of this study was to investigate possible predictors of response to cholinesterase inhibitor (ChEI) treatment, including pre-treatment progression rates and levels of the cerebrospinal fluid (CSF) biomarkers. A secondary objective was to evaluate whether treatment with ChEI changed progression.

METHODS

Out-patient individuals (n = 191) with the clinical diagnosis of Alzheimer's disease received ChEI treatment and were part of the Swedish Alzheimer Treatment Study (SATS), a prospective, longitudinal, non-randomised study in a routine clinical setting. Patients were assessed with MMSE, ADAS-cog and a global rating (CIBIC) at baseline, 2 months and every 6 months for a total period of 3 years. The following potential predictors of treatment response were investigated: age, gender, APOE epsilon 4 carrier, education, duration of disease, cognitive level, pre-treatment progression rate (in MMSE) and the levels of the CSF biomarkers A beta 42, T-tau and P-tau.

RESULTS

Fast pre-treatment progression rate was a predictor of treatment response even after adjusting for baseline severity, another positive predictor of response. Patients in the fastest quartile of pre-treatment progression rates were significantly more prone to be responders at 2 months (adjusted OR 6.6, p = 0.001) and 6 months (adjusted OR 10.4, p < 0.001) than those in the slowest progressing quartile. Moreover, the linearity of progression was significantly changed by ChEI treatment at 6 months compared to the pre-treatment period.

CONCLUSION

The rate of pre-treatment progression was the most consistent positive predictor of ChEI treatment response in the routine clinical setting. The progression rate was significantly changed by ChEI treatment.

Evolution of Abeta42 and Abeta40 levels and Abeta42/Abeta40 ratio in plasma during progression of Alzheimer's disease: a multicenter assessment

OBJECTIVE

To better understand the seemingly contradictory plasma beta-amyloid (Abeta) results in Alzheimer's disease (AD) patients by using a newly developed plasma Abeta assay, the INNO-BIA plasma Abeta forms, in a multicenter study.

METHODS

A combined retrospective analysis of plasma Abeta isoforms on mild cognitive impairment (MCI) from three large cross-sectional studies involving 643 samples from the participating German and Swedish centers.

RESULTS

Detection modules based on two different amino (N)-terminal specific Abeta monoclonal antibodies demonstrated that Abeta in plasma could be reliable quantified using a sandwich immunoassay technology with high precision, even for low Abeta42 plasma concentrations. Abeta40 and Abeta42 concentrations varied consistently with the ApoE genotype, while the Abeta42/Abeta40 ratio did not. Irrespective of the decrease of the Abeta42/Abeta40 ratio with age and MMSE, this parameter was strongly associated with AD, as defined in this study by elevated hyperphosphorylated (P-tau181P) levels in cerebrospinal fluid (CSF).

CONCLUSION

A highly robust assay for repeatedly measuring Abeta forms in plasma such as INNO-BIA plasma Abeta forms might be a useful tool in a future risk assessment of AD.

Long-term rivastigmine treatment in a routine clinical setting

OBJECTIVE

The aim of the study was to observe the effects of long-term rivastigmine treatment in patients with mild to moderate Alzheimer's disease (AD) in a routine clinical setting.

METHODS

This was a prospective, open-label, observational, multicentre, non-randomized study. Outcome measures included the Mini Mental State Examination (MMSE), the Clinician's Interview-Based Impression of Change (CIBIC) and the Alzheimer's Disease Assessment Scale - cognitive subscale (ADAS-cog).

RESULTS

Of 217 patients initiated into rivastigmine treatment, 62% (n = 135) remained on treatment for 24 months. Most patients droped out due to nursing home placement or side effects. Eighty per cent and 67% of completers exhibited a symptomatic attenuation of cognitive decline (< or = 4-point deterioration) as assessed by using the MMSE and ADAS-cog respectively. Forty-four per cent showed an unchanged/improved CIBIC rating.

CONCLUSIONS

Over 60% of patients remained on treatment for 2 years in this routine clinical setting. In patients who remained on treatment, rivastigmine appeared to stabilize their condition and prevented or delayed symptomatic decline.

Electroencephalogram variability in dementia with lewy bodies, Alzheimer's disease and controls

BACKGROUND/AIM

Dementia with Lewy bodies (DLB) is probably still underdiagnosed in the clinical setting. Previous studies have suggested a relationship between fluctuations in attention and electroencephalogram (EEG) measures. Since fluctuation in attention is a core symptom of DLB, we sought to further explore whether EEG measures could help differentiate DLB from Alzheimer's disease (AD) and healthy controls.

METHODS

The EEGs of 20 patients with DLB, 64 patients with AD and 54 elderly controls were assessed in regard to frequencies, coherence, and variability.

RESULTS

Greater variability was seen in delta-band power over 2-second intervals in parietal electrodes of DLB patients. The DLB group had a higher degree of overall coherence in the delta band and a lower degree of overall coherence in the alpha band than the other groups. Finally, EEG measures could distinguish DLB patients from AD patients and controls with areas under the receiver operating characteristic curves ranging between 0.75 and 0.80 and between 0.91 and 0.97, respectively.

CONCLUSIONS

We suggest that the difference in variability may be associated with the fluctuating cognition seen in DLB. This might have clinical implications as guidance in the diagnosis of DLB. The EEG analysis is simple enough to be possible to apply in clinical practice.

Development of screening guidelines and clinical criteria for predementia Alzheimer's disease. The DESCRIPA Study

BACKGROUND

There is an urgent need to identify subjects with Alzheimer's disease (AD) in the predementia phase, but validated diagnostic approaches are currently lacking. In this paper, we present the background, design and methods of a study, which aims to develop clinical criteria for predementia AD. We also present baseline characteristics of the subjects included. The study was part of the multicentre DESCRIPA project, which is being conducted within the network of the European Alzheimer's Disease Consortium.

METHODS

Clinical criteria will be based on a prospective cohort study of non-demented subjects older than 55 years and referred to a memory clinic. At baseline, a number of markers and risk factors for AD were collected, including demographic variables, measures of performance in activities of daily living, cognitive, neuroimaging and genetic markers, and serum and cerebrospinal fluid markers. Subjects will be reassessed annually for 2-3 years, and we will evaluate which combination of variables best predicts AD-type dementia at follow-up.

RESULTS

Between 2003 and 2005, 881 subjects were included from 20 memory clinics. Subjects were on average 70.3 years old, and had 10.4 years of education. The average score on the Mini-Mental State Examination was 27.4.

Effects of a goal-oriented rehabilitation program in mild cognitive impairment: a pilot study

BACKGROUND

Memory disturbance, deficient concentration, and fatigue are symptoms seen in amnestic mild cognitive impairment (MCI) as well as in mild traumatic brain injury (TBI). The aim of this study was to assess if an established rehabilitation program commonly used in TBI can aid MCI patients to develop compensatory memory strategies that can improve their cognition, occupational performance, and quality of life (QoL).

METHODS

Fifteen patients with MCI participated in the program 2 days per week for 8 weeks. Cognitive function, occupational performance, and self-perceived QoL were assessed at baseline, at the end of the intervention, and at follow-up after 6 months.

RESULTS

Significant improvements were seen in cognitive processing speed, occupational performance, and in some of the QoL domains.

CONCLUSION

As this goal-oriented rehabilitation program in MCI resulted in some improvements in cognition, occupational performance, and QoL, further randomized controlled studies are warranted.

Prediction of Alzheimer's disease using a cerebrospinal fluid pattern of C-terminally truncated beta-amyloid peptides

BACKGROUND

Identifying individuals at high risk of developing Alzheimer's disease (AD) is important for future therapeutic strategies, and there is a clinical need for diagnostic biomarkers to identify incipient AD.

OBJECTIVE

The aim of the present study was to investigate if the AD-associated Abeta peptide pattern recently found in cerebrospinal fluid (CSF) could discriminate between patients with incipient AD and those with stable mild cognitive impairment (MCI) by analyzing CSF from patients with MCI at baseline.

METHODS

The levels of Abeta(1-37, -38, -39, -40, -42) were analyzed by Abeta-SDS-PAGE/immunoblot in CSF from 19 healthy controls, 25 patients with stable MCI and from 25 patients with MCI who later developed AD during 4- to 6-year follow-up.

RESULTS

All healthy controls and 20 out of 22 patients who developed AD were correctly classified by their baseline Abeta peptide pattern. In 9 out of 25 stable MCI patients, the pattern indicated incipient AD in spite of clinical nonconversion. Interestingly, these individuals had apolipoprotein E genotypes and CSF levels of tau and phospho-tau that are known to be associated with high risk of AD.

CONCLUSION

Altogether, our study reveals the novel finding that the Abeta peptide pattern is able to predict AD in patients with MCI with a sensitivity of 91% and specificity of 64%. The specificity would increase to 94% if the high-risk patients in the stable MCI cohort developed AD during extended follow-up.

The period of hypotension following orthostatic challenge is prolonged in dementia with Lewy bodies

OBJECTIVES

To determine whether orthostatic hypotension (OH) is more common in patients with dementia than in older people without cognitive impairment and to identify key differences in the profile of the orthostatic response and the pulse drive during orthostatic challenge between Alzheimer's disease (AD) and dementia with Lewy bodies (DLB).

METHODS

The orthostatic response was evaluated in 235 patients with AD, 52 patients with DLB and 62 elderly controls. The blood pressure and pulse rate were measured in supine position, immediately after standing up and after 1, 3, 5 and 10 min of standing. OH was defined as a reduction of systolic blood pressure (SBP) of at least 20 mm Hg or a reduction of diastolic blood pressure (DBP) of at least 10 mm Hg.

RESULTS

OH occurred in 69% of the DLB patients and in 42% of the AD patients, but only in 13% of the controls (p<0.001 controls vs AD and controls vs DLB, p=0.001 AD vs DLB) The DLB patients had a greater drop in SBP than the other study groups during orthostatic challenge and had a more prolonged period of orthostasis. The pulse drive on orthostatic challenge was similar in between groups. However, in the DLB group it was not adequate to restore the blood pressure to supine values.

CONCLUSIONS

Patients with DLB react different to orthostatic challenge than patients with AD or controls, with important clinical implications for key disease symptoms and treatment.

Usefulness of computed tomography linear measurements in diagnosing Alzheimer's disease

BACKGROUND

Medial temporal lobe atrophy (MTA) is an early sign of Alzheimer's disease (AD). The current method of choice for measuring MTA is volumetric measurement based on 3D magnetic resonance imaging (MRI), but this complicated method has not been implemented clinically.

PURPOSE

To investigate whether simple computed tomography (CT) linear measurements of the brain could be of value in AD workup.

MATERIAL AND METHODS

Fifty-nine healthy control subjects and 248 AD subjects were recruited. They were evaluated using a comprehensive clinical workup. A series of linear CT measurements were obtained from brain CT.

RESULTS

In discriminant analysis, the temporal horn ratio and the suprasellar cistern ratio were the atrophy factors that contributed most significantly to the diagnoses. Combined with other clinical factors (apolipoprotein E4 genotype), a correct AD classification of 90.2% was achieved.

CONCLUSION

CT linear measurements could be of value in the workup of AD patients, considering the inexpensiveness and availability of CT as well as the simplicity of linear measurements.

Plasma and CSF serpins in Alzheimer disease and dementia with Lewy bodies

OBJECTIVE

Serine protease inhibitors (serpins), the acute phase reactants and regulators of the proteolytic processing of proteins, have been recognized as potential contributors to the pathogenesis of Alzheimer disease (AD). We measured plasma and CSF levels of serpins in controls and patients with dementia.

METHODS

Using rocket immunoelectrophoresis, ELISA, and Luminex xMAP technology, we analyzed plasma levels of alpha(1)-antichymotrypsin and alpha(1)-antitrypsin, and CSF levels of alpha(1)-antichymotrypsin, alpha(1)-antitrypsin, and neuroserpin along with three standard biomarkers (total tau, tau phosphorylated at threonine-181, and the A beta(1-42)) in patients with AD (n = 258), patients with dementia with Lewy bodies (DLB; n = 38), and age-matched controls (n = 37).

RESULTS

The level of CSF neuroserpin was significantly higher in AD compared with controls and DLB, whereas CSF alpha(1)-antichymotrypsin and alpha(1)-antitrypsin were significantly higher in both AD and DLB groups than in controls. Results from logistic regression analyses demonstrate a relationship between higher CSF levels of alpha(1)-antichymotrypsin and neuroserpin and increased predicted probability and odds ratios (ORs) of AD (OR 5.3, 95% CI 1.3 to 20.8 and OR 3.3, CI 1.3 to 8.8). Furthermore, a logistic regression model based on CSF alpha(1)-antichymotrypsin, neuroserpin, and A beta(1-42) enabled us to discriminate between AD patients and controls with a sensitivity of 94.7% and a specificity of 77.8%.

CONCLUSIONS

Higher CSF levels of neuroserpin and alpha(1)-antichymotrypsin were associated with the clinical diagnosis of Alzheimer disease (AD) and facilitated the diagnostic classification of AD vs controls. CSF serpin levels did not improve the diagnostic classification of AD vs dementia with Lewy bodies.

Identification of a novel panel of cerebrospinal fluid biomarkers for Alzheimer's disease

An early and accurate diagnosis of Alzheimer's disease (AD) is required to initiate symptomatic treatment with currently approved drugs and will be of even greater importance if disease modifying compounds in development display a clinical effect. Protein profiles of human cerebrospinal fluid samples from AD patients (n=95) and population-based healthy controls (n=72) were analyzed by SELDI-TOF-MS in order to discover and characterize novel candidate biomarker combinations that differentiate AD patients from normal aging in this explorative study. Thirty candidate biomarkers (ROC AUC>0.7) were discovered that could differentiate patients with AD from healthy controls. Protein sequence determination and positive identification of 15 biomarkers revealed potential associations between the identified markers and AD pathogenesis. A multi-marker combination of five peaks could distinguish AD from healthy control individuals with high sensitivity (97%) and specificity (98%). The panel of five markers was tested on a blinded independent data set of 30 AD samples and 28 controls giving 100% sensitivity and 97% specificity. This novel panel of biomarkers could potentially be used to improve the accuracy of diagnosis of AD.

Changes in the activity and protein levels of CSF acetylcholinesterases in relation to cognitive function of patients with mild Alzheimer's disease following chronic donepezil treatment

OBJECTIVES

To evaluate long-term changes in acetylcholinesterase (AChE) activity in CSF and blood following donepezil treatment in relation to the concentration of donepezil and cognition in AD patients.

METHODS

CSF or blood (or both) samples of a total of 104 patients with mild AD were used [MMSE score 23 +/- 0.4; age 75 +/- 1 years (mean +/- SEM); n=53 for CSF and n=51 for plasma/red blood cell (RBC) samples]. The patients were treated with 5 or 10 mg/day donepezil and clinically followed for 2 years. The CSF and RBC AChE activities were measured by the Ellman's direct colorimetric assay. Protein levels of two variants of AChE ("read-through" AChE-R and synaptic AChE-S) were determined by an ELISA-like method.

RESULTS

The plasma donepezil concentration was dose-dependent (between 30 and 60 ng/mL in the 5-mg and 10-mg group, respectively). The CSF donepezil concentration was 10 times lower than the plasma level and showed dose- and time-dependent kinetics. The RBC AChE inhibition was moderate (19-29%). CSF AChE-S inhibition was estimated to 30-40% in the 5-mg and 45-55% in the 10-mg group. Positive correlations were observed between the CSF AChE inhibition, an increased protein level of the AChE-R variant and MMSE examination. Patients with high AChE inhibition (>or=45%) showed a stabilized MMSE test result after up to two years, while a significant decline was observed in AD patients with lower AChE inhibition (<or=30%).

CONCLUSIONS

An increase in the protein level of the AChE-R variant corresponded to a high AChE inhibition in CSF and favored less cognitive deterioration.

CSF biomarkers for Alzheimer's Disease: levels of beta-amyloid, tau, phosphorylated tau relate to clinical symptoms and survival

Cerebrospinal fluid (CSF) samples from 21 patients with a clinical diagnosis of Alzheimer's disease (AD) participating in a 5-year treatment study with the choline esterase inhibitor tacrin were retrospectively analyzed for the contents of beta-amyloid (Abeta42), total tau (T-tau) and phosphorylated tau (P-tau). A significant positive correlation between the level of P-tau and the number of symptoms according to the DSM-IV criteria (p = 0.041) and the NINCDS-ADRDA (p = 0.029) was observed (i.e. higher levels were found in cases with more symptoms). A significant positive correlation between T-tau, P-tau and ADAS-cog score was identified (i.e. higher levels were found with more severe cognitive dysfunction). Patients who died during the 5-year follow-up had significantly lower levels of Abeta42 (p = 0.011) than those who were still alive. Patients who had died in a 6-year follow-up had significantly lower levels of Abeta42 (p = 0.034) and higher levels of T-tau (p = 0.041) than patients still alive.

CONCLUSION

CSF biomarkers do aid the clinical diagnosis of AD. Increased levels of P-tau and T-tau are possible markers for severity and abundance of symptoms in AD. Low levels of Abeta42 may indicate a higher risk of early death in AD.

Lower gait speed in older women with dementia compared with controls

Movement time is increased in patients with Alzheimer's disease.

OBJECTIVES

To study differences in movement time and ability to increase speed in older women with dementia.

METHODS

Four tests were performed at self-selected and maximal speed: walking 2 x 15 m, walking between parallel lines, 'get up and go' (GUG) and rising from lying supine. Twenty-two patients and 22 controls (mean ages 81 and 86 years, respectively) were included in the study.

RESULTS

In the groups over 80 years, walking and GUG at both speeds and rising from lying supine from the left at self-selected speed were significantly slower among patients (20-30%). Both patients and controls were able to increase movement speed when changing from self-selected to maximal speed (13-27%). Patients with Alzheimer's disease had lower self-selected walking speed compared with patients with other types of dementia (p = 0.048).

CONCLUSION

Testing physical performance in two different speeds was feasible in patients with dementia. Patients had slower gait speed and were slower in the functional tests, such as GUG, but the capacity to increase speed seemed intact.

Five-year outcome of cholinergic treatment of Alzheimer's disease: early response predicts prolonged time until nursing home placement, but does not alter life expectancy

Fifty consecutive outpatients with Alzheimer's disease (AD) received treatment with the cholinesterase inhibitor tacrine in an open longitudinal study. Assessments using Mini-Mental State Examination, Alzheimer's Disease Assessment Scale - cognitive subscale, and a global rating were made at baseline and at 6, 12, 24, 36, 48 and 60 months. Three outcome groups were characterized: responders, unchanged and deteriorated. Additional outcome measures were time until nursing home placement, and mortality rate. At 6 months -75%, at 12 months -42%, at 24 months -20%, and after that 10% of the patients still on medication had improved or remained stable. The mortality rate did not differ between the outcome groups. Response to tacrine treatment at 6 or 12 months was found to predict a prolonged time until nursing home placement. No predictors for a positive treatment response could be identified at baseline.

Inflammatory markers in matched plasma and cerebrospinal fluid from patients with Alzheimer's disease

It has been suggested that a number of molecules associated with inflammation are involved in the pathogenesis of Alzheimer's disease (AD). We measured the levels of alpha(1)-antichymotrypsin (ACT), alpha(1)-antitrypsin (AAT), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1) and oxidised low-density lipoprotein (oxLDL) in matched cerebrospinal fluid (CSF) and plasma of 141 patients with probable AD. We found a significant relationship between CSF and plasma levels of ACT (r = 0.4, p < 0.001), IL-6 (r = 0.74, p < 0.001), MCP-1 (r = 0.71, p < 0.001), and a borderline relationship between CSF and plasma oxLDL (r = 0.22, p < 0.05). In addition, linear regression analysis revealed a positive correlation between levels of CSF-ACT and oxLDL (p < 0.001), but an inverse relation between levels of CSF ACT, CSF AAT and MCP-1 (p < 0.001). A significant correlation was also found between levels of CSF ACT, oxLDL and the ratio of CSF to serum albumin, which is used as a measure of the blood-brain barrier function. Our data extend previous reports regarding the inflammatory markers in the plasma and CSF of patients with AD and provide good evidence that levels of ACT, IL-6, MCP-1 and oxLDL in plasma and CSF might be candidates as biomarkers for monitoring the inflammatory process in AD.

Increased frequency of a new polymorphism in the cell division cycle 2 (cdc2) gene in patients with Alzheimer's disease and frontotemporal dementia

Recent studies show linkage between Alzheimer's disease (AD) and two loci on chromosome 10. The cell division cycle 2 (cdc2) gene is located close to one of the chromosome 10 markers, and is a candidate gene for AD since it is involved in the pathogenesis of AD. We sequenced coding exons and flanking intronic sequences and the promoter region on the cdc2 gene and found three new single nucleotide polymorphisms (SNPs). We analyzed 272 Caucasian AD cases, 160 controls and 70 cases with frontotemporal dementia (FTD) for these SNPs. Homozygosity for one of the SNPs (Ex6+7I/D) was more frequent in both AD and FTD cases than in controls. In the combined tauopathy (AD and FTD) group the odds ratio (OR) was 1.77 (95% CI 1.19-2.63) for the Ex6+7II genotype. Our findings suggest that the Ex6+7I allele is associated with tauopathies, both AD and FTD.

Cerebrospinal fluid levels of biomarkers and activity of acetylcholinesterase (AChE) and butyrylcholinesterase in AD patients before and after treatment with different AChE inhibitors

In order to evaluate the biochemical effects of long-term treatment with inhibitors of acetylcholinesterase (AChE) in patients with Alzheimer's disease (AD), we measured the activities of AChE and butyrylcholinesterase (BuChe) and the concentrations of beta-amyloid (1-42), tau and phosphorylated tau proteins in the cerebrospinal fluid (CSF). A total of 91 patients suffering from probable AD of mild to moderate degree were treated for 6 months with donepezil (n=59), galantamine (n=15), rivastigmine (n=10), or placebo (n=7). AChE activity in CSF was significantly increased after treatment with donepezil and galantamine; the opposite was observed in the rivastigmine-treated group. Untreated patients did not show any AChE activity variation. BuChE did not show any change in any of the groups studied. Mean values of beta-amyloid(1-42), total tau and phosphorylated tau also did not vary significantly. We conclude that AChE inhibitors induce different effects on CSF AChE activity, while other CSF biomarkers are not significantly affected by treatment.

Tacrine and rate of progression in Alzheimer's disease--relation to ApoE allele genotype

Today, cognitive impairment can be successfully treated with acetylcholine esterase inhibitors (AChE-I) in many, but not all, patients with Alzheimer's disease (AD). To investigate the relation between tacrine treatment, inheritance of ApoE epsilon4 alleles, and rate of progression, the differences in MMSE and CIBIC scores (efficacy parameters) after 6 and 12 months of tacrine (an AChE-I) treatment were investigated in 145 AD patients. Of these, 84 were ApoE epsilon4-positive (ApoE4) and 61 were ApoE epsilon4-negative (ApoE2-3). No differences were found after 6 months of treatment, but after 12 months the CIBIC scores revealed that the ApoE4 patients had declined more than the ApoE2-3 patients (p < 0.05). No differences were found for the last 6 months of treatment. The results primarily suggest a faster rate of decline in the ApoE4 AD compared to the ApoE2-3, but may also reflect that ApoE epsilon4 genotype inheritance is a negative predictor of treatment effect of tacrine in AD patients.

Processing of neuropeptide Y, galanin, and somatostatin in the cerebrospinal fluid of patients with Alzheimer's disease and frontotemporal dementia

Alzheimer's disease (AD) and frontotemporal dementia (FTD) are two prevalent neurodegenerative disorders for which the causes are unknown, except in rare familial cases. Several changes in neuropeptide levels as measured by radioimmunoassay (RIA) have been observed in these illnesses. Somatostatin (SOM) levels in cerebrospinal fluid (CSF) are consistently decreased in AD and FTD. Neuropeptide Y (NPY) levels are decreased in AD, but normal in FTD. Galanin (GAL) levels increase with the duration of illness in AD patients. The majority of studies of neuropeptides in CSF have not been verified by HPLC. The observed decrease in a neuropeptide level as measured by RIA may therefore reflect an altered synthesis or extracellular processing, resulting in neuropeptide fragments that may or may not be detected by RIA. Matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-MS) has been shown to be a powerful technique in the analysis of biological materials without any pre-treatment, by detecting peptides and proteins at a specific mass-to-charge (m/z) ratio. We studied the processing of the neuropeptides NPY, NPY, SOM and GAL in the cerebrospinal fluid of patients with AD (n = 3), FTD (n = 3) and controls (n = 2) using MALDI-MS. We found that considerable inter-individual variability exists in the rate of neuropeptide metabolism in CSF, as well as the number of peptide fragments formed. Certain patients showed differences in the processing of specific neuropeptides, relative to other patients and controls. This analysis of the metabolic processing of neuropeptides in CSF yielded a large amount of data for each individual studied. Further studies are required to determine the changes in neuropeptide processing that can be associated with AD and FTD. With further investigations using MALDI-MS analysis, it may be possible to identify a neuropeptide fragment or processing enzyme that can be correlated to these disease states.

Cerebrospinal fluid tau and beta-amyloid(1-42) in dementia disorders

The reliability of cerebrospinal fluid (CSF)-tau and CSF-beta-amyloid assays for diagnosis of Alzheimer's disease and other dementing disorders such as frontotemporal dementia (FTD), dementia with Lewy bodies (DLB) and Creutzfeldt-Jakob disease (CJD) is reviewed. CSF assessment of the two proteins is useful in early diagnosis of AD and to differentiate it from FTD and DLB. Extremely high CSF-tau levels can discriminate CJD from AD.

Decreased levels of intrathecal interleukin 1 receptor antagonist in Alzheimer's disease

A growing body of evidence points out the potential role of inflammatory mechanisms in the pathophysiology of brain damage in dementia. In previous studies, we have demonstrated intrathecal production of the proinflammatory cytokine tumor necrosis factor (TNF)alpha in patients with Alzheimer's disease (AD). The aim of the present study was to investigate the downstream products of TNF-alpha expression including interleukin (IL)1beta and its naturally occurring antagonist IL-1 receptor agonist (ra) in patients with AD. The cytokine levels were related to neuronal damage, as measured by intrathecal tau and beta-amyloid concentration and certain clinical features of the disease. Fifty-two patients with AD and 25 healthy controls were analyzed with respect to cerebrospinal fluid (CSF) levels of IL-1beta and IL-1ra. CSF IL-1beta was neither detectable in CSF of AD nor in control CSF. In contrast, a significantly lower (p < 0.01) number of patients (24 of 49) than of controls (20 of 24) showed detectable levels of IL-1ra in the CSF. The intrathecal levels of IL-1ra were significantly lower in patients with AD than in the controls. Our study demonstrates a decreased production of the anti-inflammatory compound IL-1ra, suggesting a propensity towards inflammation in patients with AD.

Both total and phosphorylated tau are increased in Alzheimer's disease

BACKGROUND

[corrected] Pathological tau protein concentrations in CSF are found in both Alzheimer's disease (AD) and frontotemporal dementia (FTD), but studies on brain tissue have suggested that the tau pathology in AD differs from that in FTD and that the difference may be related to the degree of phosphorylation. As CSF tau protein is increased after stroke, tau may also be implicated in the pathophysiology of vascular dementia, of which subcortical arteriosclerotic encephalopathy (SAE) is a putative subtype.

OBJECTIVES

To investigate the nature of tau protein in CSF and the involvement of total CSF tau and phosphorylated CSF tau (phosphotau) in various types of dementia.

METHODS

Using ELISAs for total tau and tau phosphorylated at Thr181 (phosphotau), the CSF concentrations of total tau and phosphotau were determined in patients with probable and possible AD (n=41 and 19, respectively), FTD (n=18), SAE (n=17), and Parkinson's disease (PD; n=15) and in age matched controls (n=17). All the antibodies stained the lower molecular weight bands, whereas only the antibodies that recognise phosphorylated tau stained the higher molecular bands.

RESULTS

Both CSF tau and CSF phosphotau were increased in probable AD compared with FTD (p<0.001), SAE (p<0.001), PD (p<0.001), and controls (p<0.001). CSF phosphotau was increased in possible AD compared with FTD (p<0.001) and SAE (p<0.001). CSF tau and CSF phosphotau were positively correlated in all the groups. Molecular weight forms of tau ranging from 25 kDa to 80 kDa were found in the CSF CONCLUSION: Both phosphorylated and unphosphorylated tau isoforms were present in the CSF, and tau protein appeared in both truncated and full length forms. The results suggest that the CSF concentrations of tau and phosphotau are increased in about two thirds of patients with probable AD and in half of those with possible AD but are normal in FTD, SAE, and PD compared with normal aging. Values in the normal range do not exclude AD.

Differential increase in cerebrospinal fluid-acetylcholinesterase after treatment with acetylcholinesterase inhibitors in patients with Alzheimer's disease

The clinical significance and the effects of pharmacological treatment of patients with Alzheimer's disease (AD) were evaluated by measurement of acetylcholinesterase (AChE) in the cerebrospinal fluid (CSF). CSF-AChE of AD patients was lower, not significantly, compared with controls. However, CSF-AChE was significantly increased after treatment of AD patients with AChE inhibitors (donepezil and galantamine). The increase was higher in patients treated with donezepil than in those treated with galantamine, which might be related to different mechanisms for the substances. The increase was also dose-dependent, and was especially marked in patients showing a clinical response. These data suggest that CSF biomarkers are capable not only of identifying a biochemical effect of drugs, but also of differentiating between different compounds in a dose-dependent manner.

No association between the alpha2-macroglobulin (A2M) deletion and Alzheimer's disease, and no change in A2M mRNA, protein, or protein expression

A polymorphism consisting of a deletion near the 5' splice site of exon 18 on the alpha2-macroglobulin (A2M) gene (A2M-2) has been suggested to be associated with Alzheimer's disease (AD) in family-based studies. We studied the A2M-2 allele together with the ApoE alleles in a large series on patients with AD (n = 449) and age-matched controls (n = 349). Neuropathologically confirmed diagnoses were available in 199 cases (94 AD and 107 control cases). We found no increase in A2M-2 genotype or allele frequencies in AD (27.5% and 14.6%) versus controls (26.4% and 14.9%). In contrast, a marked increase (p < 0.0001) in ApoE epsilon4 genotype or allele frequencies was found in AD (66.6% and 41.2%) as compared with controls (29.8% and 16.5%), suggesting sufficient statistical power in our sample. No relation was found between the A2M-2 and the ApoE epsilon4 allele. No change in A2M exon 17-18 mRNA size or sequence or A2M protein size was found in cases carrying the A2M-2 deletion, suggesting that there is no biological consequences of the A2M intronic deletion. No change in A2M protein level in cerebrospinal fluid was found in AD, suggesting that the A2M-2 allele does not effect the A2M protein expression in the brain. The lack of an association between the A2M-2 allele and AD in the present study, and the lack of abnormalities in the A2M mRNA or protein suggest that the A2M-2 allele is not associated with AD.

Evaluation of CSF-tau and CSF-Abeta42 as diagnostic markers for Alzheimer disease in clinical practice

OBJECTIVE

To evaluate the diagnostic potential of cerebrospinal fluid (CSF) levels of tau and beta-amyloid protein ending at amino acid 42 (Abeta42) as biomarkers for Alzheimer disease (AD) in clinical practice.

DESIGN

A 1-year prospective study.

SETTING

Community population-based sample of all consecutive patients admitted for investigation of cognitive symptoms to the Piteå River Valley Hospital, Piteå, Sweden.

PATIENTS

A total of 241 patients with probable AD (n = 105), possible AD (n = 58), vascular dementia (n = 23), mild cognitive impairment (n = 20), Lewy body dementia (n = 9), other neurological disorders (n = 3), and psychiatric disorders (n = 5) and nondemented individuals (n = 18).

MAIN OUTCOME MEASURES

Cerebrospinal fluid tau and CSF-Abeta42 were assayed each week as routine clinical neurochemical analyses. Sensitivity and specificity were defined using the regression line from 100 control subjects from a multicenter study. Positive and negative predictive values were calculated for different prevalence rates of AD.

RESULTS

We found increased CSF-tau and decreased CSF-Abeta42 levels in probable and possible AD. Sensitivity was 94% for probable AD, 88% for possible AD, and 75% for mild cognitive impairment, whereas specificity was 100% for psychiatric disorders and 89% for nondemented. Specificity was lower in Lewy body dementia (67%) mainly because of low CSF-Abeta42 levels and in vascular dementia (48%) mainly because of high CSF-tau levels. Sensitivity for CSF-tau and CSF-Abeta42 increased in patients with AD possessing the ApoE epsilon4 allele, approaching 100%. At a prevalence of AD of 45%, the positive predictive value was 90% and the negative predictive value was 95%.

CONCLUSIONS

Cerebrospinal fluid tau and CSF-Abeta42 have so far been studied in research settings, under conditions providing data on the optimal performance. We examined a prospective patient sample, with assays run in clinical routine, giving figures closer to the true performance of CSF-tau and CSF-Abeta42. The predictive value for AD was greater than 90%. Therefore, these biomarkers may have a role in the clinical workup of patients with cognitive impairment, especially to differentiate early AD from normal aging and psychiatric disorders.

CSF levels of tau, beta-amyloid(1-42) and GAP-43 in frontotemporal dementia, other types of dementia and normal aging

Cerebrospinal fluid (CSF) levels of tau, beta-amyloid(1-42) and growth-associated protein 43 (GAP-43) were studied in patients with frontotemporal dementia (FTD; n = 17), Alzheimer's disease (AD; n = 60), subcortical white-matter dementia (SWD; n = 24), Parkinson's disease (PD; n = 23) and dysthymia (n = 19) and in age-matched controls (n = 32). CSF-tau was significantly increased only in AD, and CSF-beta-amyloid(1-42) was significantly decreased in AD and SWD as compared to controls, and in AD compared to FTD. CSF-GAP-43 was significantly decreased only in PD. The GAP-43/tau ratio was decreased in all the patient groups except the dysthymia group compared to controls. A positive correlation was found between CSF-GAP-43 and CSF-tau in all groups. The results suggest normal levels of CSF-tau and CSF-beta-amyloid(1-42) in FTD, which will aid in the clinical separation of FTD from AD. In SWD, decreased levels of CSF-beta-amyloid(1-42) suggest concomitant involvement of vascular and amyloid protein mechanisms.

Standardization of measurement of beta-amyloid(1-42) in cerebrospinal fluid and plasma

The standardization and clinical validation of the measurement of beta-amyloid(1-42) (Abeta42) in cerebrospinal fluid (CSF), plasma and urine is described using a commercially available sandwich-type ELISA with 21F12 and 3D6 as monoclonal antibodies. The INNOTEST beta-amyloid(1-42) allows the specific and reliable measurement of(1-42) amyloid peptides in CSF and plasma. The Abeta42 concentrations in serum and urine were below the detection limit. In plasma, no differences were found in Abeta42 levels between controls and patients with different neurodegenerative disorders (Alzheimer's disease (AD), Lewy body disease (LBD), others). In contrast, CSF-Abeta42 concentrations were lower in AD and LBD patients as compared to controls. No correlation was found in AD patients between CSF and plasma concentrations of Abeta42 or between CSF Abeta42 levels and blood-brain-barrier function. The quantitative outcome of the test is in part dependent on confounding factors such as tube type, freeze/thaw cycles, temperature of incubation, standard preparation protocol, and antibody selection. Notwithstanding these aspects, it emerged that Abeta42 is a useful biochemical marker for the diagnosis of AD patients, but there is a need for an international Abeta standard, a universally accepted protocol for CSF preparation, and a thorough evaluation of assay performance in function of the boundary conditions.

Plasma levels of 24S-hydroxycholesterol in patients with neurological diseases

The brain is the exclusive or almost exclusive site of formation of 24S-hydroxycholesterol and we have shown that the circulating level of 24S-hydroxycholesterol is dependent upon the relation between cerebral production and hepatic clearance. In the present work we determined plasma levels of 24S-hydroxycholesterol in patients with various neurological diseases. Eleven subjects with brain death occurring 6-10 h before collection of the plasma samples had markedly reduced circulating levels of 24S-hydroxycholesterol (-43%, P<0.001). Patients with advanced Alzheimer's disease and cerebral inflammatory diseases had slightly lower levels of 24S-hydroxycholesterol in plasma when compared to matched controls. Patients with acute ischemic stroke, multiple sclerosis and primary brain tumors had levels not significantly different from those of controls. The conditions leading to reduced plasma levels of 24S-hydroxycholesterol had no significant effect on plasma levels of another side-chain oxidized oxysterol, 27-hydroxycholesterol. Except for conditions characterized by very marked destruction of the central nervous system, different severe neurological diseases seem to have relatively small effects on the flux of 24S-hydroxycholesterol from the brain.

TNF gene polymorphism and its relation to intracerebral production of TNFalpha and TNFbeta in AD

OBJECTIVE

To analyze the extent of tumor necrosis factor-alpha (TNFalpha) and TNFbeta gene polymorphism in patients with AD and to relate it to intrathecal levels of these cytokines.

METHODS

Analyses of TNFalpha and TNFbeta gene polymorphism were performed using PCR in 52 patients with AD and in 25 control subjects, and the levels of corresponding cytokines were analyzed using ELISA.

RESULTS

Patients with AD displayed significantly higher intrathecal levels of TNFalpha, but not TNFbeta, compared with the control subjects. The levels of these cytokines did not differ significantly in patients displaying different alleles of the TNF gene.

CONCLUSIONS

Results indicate that increased intrathecal production of TNFalpha in AD is preferentially controlled by environmental stimuli rather than genetic makeup.

Cytoskeleton proteins in CSF distinguish frontotemporal dementia from AD

OBJECTIVE AND BACKGROUND

To investigate the CSF levels of tau and the light neurofilament protein (NFL) in patients with frontotemporal dementia (FTD) and other common dementia disorders as well as normal control subjects. Both proteins have been implicated in the pathophysiology of FTD.

METHODS

CSF levels of tau and NFL were investigated in 18 patients with FTD, 21 patients with early-onset AD (EAD), 21 patients with late-onset AD (LAD), and 18 age-matched control subjects.

RESULTS

Mean +/- SD CSF NFL levels were increased in patients with FTD (1442 +/- 1183 pg/mL; p < 0.05) and LAD (1006 +/- 727 pg/mL; p < 0.001) compared with control subjects (241 +/- 166 pg/mL) and in LAD compared with EAD (498 +/- 236 pg/mL; p < 0.05), and tended to be increased in FTD compared with EAD. CSF tau levels were increased in EAD (751 +/- 394 pg/mL; p < 0.01) and LAD (699 +/- 319 pg/mL; p < 0.01) compared with control subjects (375 +/- 170 pg/mL), and in EAD (p < 0.001) and LAD (p < 0. 01) compared with FTD (354 +/- 140 pg/mL). CSF NFL correlated positively with degree of cognitive impairment in FTD (r = 0.59; p < 0.05) and LAD (r = 0.61; p < 0.01). No significant differences were found in CSF NFL or CSF tau when comparing patients who did and did not possess the APOE-epsilon4 allele within each diagnostic group.

CONCLUSION

The results suggest a differential involvement of these cytoskeleton proteins in FTD and EAD, with NFL primarily involved in the pathophysiology of FTD and tau in that of EAD. The increase in CSF NFL found in LAD might reflect the white-matter degeneration found in a proportion of LAD cases.

Measurement of apolipoprotein E (apoE) in cerebrospinal fluid

Apolipoprotein E (apoE) is a protein involved in transport of lipids and has been implicated to play an important role in regeneration after nerve injury. Determination of apoE in cerebrospinal fluid (CSF) thus have a potential interest when studying different forms of brain damage and as a marker of ongoing regenerative processes in the brain. However, previous studies on CSF-ApoE in Alzheimer's disease (AD) have given inconclusive results. Such inconsistent results might be related to confounding factors interfering with sample handling and/or analyses, which have not been fully elucidated. We therefore examined different potential confounding factors for analyses of apoE in CSF and also developed a new enzyme linked immunosorbent assay (ELISA). The hydrophobic character of ApoE resulted in adsorption to different types of test tubes commonly used for collection of CSF at lumbar puncture, resulting in falsely low levels. This makes CSF handling critical, especially if samples are taken in different types of tubes, or is transferred to new tubes. Taking this confounding factors in consideration and analysing patient and control CSF handled in the same way and using the new ELISA, we could confirm our previous finding of reduced levels of ApoE in AD, (3.4 +/- 1.3 mg/l) compared with controls (4.5 +/- 2.7 mg/l) (p = 0.045). Both in the AD and in the control group, higher levels of CSF-ApoE was found in individuals possessing the ApoE4 alleles. Our results support that CSF-ApoE is reduced in AD, and that handling of CSF is a critical factor, which may explain the discrepant results from previous studies. Differences in the amount of patients and controls possessing the ApoE4 allele included might also increase the variance between different studies.

Sensitivity, specificity, and stability of CSF-tau in AD in a community-based patient sample

OBJECTIVE

To evaluate the sensitivity and specificity of CSF-tau in clinical practice as a diagnostic marker for AD compared with normal aging and depression, to study the stability of CSF-tau in longitudinal samples, and to determine whether CSF-tau levels are influenced by different covariates such as gender, age, duration or severity of disease, or possession of the APOE-epsilon4 allele.

METHODS

Consecutive AD patients from a community-based sample were studied, including 407 patients with AD (274 with probable AD and 133 with possible AD), 28 patients with depression, and 65 healthy elderly control subjects. A follow-up lumbar puncture was performed in 192 AD patients after approximately 1 year. CSF-tau was determined using a sandwich ELISA, which was run as a routine clinical neurochemical analysis.

RESULTS

CSF-tau was increased in probable (690+/-341 pg/mL; p < 0.0001) and possible (661+/-447 pg/mL; p < 0.0001) AD, but not in depression (231+/-110 pg/mL) compared with control subjects (227+/-101 pg/mL). Receiver operating characteristics analysis showed that a cutoff level of 302 pg/mL resulted in a sensitivity of 93% (95% CI, 90-96%) and a specificity of 86% (95% CI, 75-94%), with an area under the curve of 0.95 to discriminate AD from control subjects. Within the AD group, CSF-tau did not differ significantly between baseline and follow-up investigations, and was relatively stable between baseline and 1-year follow-up levels, with a coefficient of variation of 21.0%. High CSF-tau levels were also found in most AD patients with very short duration of dementia, and with Mini-Mental State Examination scores >23 (n = 205). In total, 193 of 205 patients (sensitivity, 94%) had a CSF-tau level higher than 302 pg/mL.

CONCLUSIONS

CSF-tau has a high sensitivity and specificity to differentiate AD from normal aging and depression, as demonstrated in a large community-based series of consecutive AD patients during which analyses were run continually in a clinical neurochemical laboratory. The increase in CSF-tau is found very early in the disease process in AD, is stable over time, and has a low interindividual variation on repeated sampling. Although high CSF-tau is found in some neurologic conditions (e.g., stroke), these findings suggest that CSF-tau may be of use to help in differentiating AD from normal aging and depression, especially early in the course of the disease, when the symptoms are vague and the diagnosis is especially difficult.