Polymorphism in the cholesterol 24S-hydroxylase gene is associated with Alzheimer's disease

Cholesterol and 24S-hydroxycholesterol are involved in the pathogenesis of Alzheimer's disease (AD). Increased serum cholesterol concentrations have been detected in patients with AD. 24S-Hydroxycholesterol is the primary cholesterol elimination product of the brain and possesses neurotoxic properties in vitro. The enzyme catalyzing the conversion of cholesterol to 24S-hydroxycholesterol, cholesterol 24S-hydroxylase (CYP46), is mainly expressed in neurons. Concentrations of 24S-hydroxycholesterol in cerebrospinal fluid (CSF) and serum differ significantly between AD patients and non-demented subjects. To test the hypothesis if polymorphisms in the CYP46 gene might influence the function of the respective enzyme and thus cholesterol metabolism in the human brain, we screened for polymorphisms in 114 AD patients and 144 healthy controls. Two intronic single nucleotide polymorphisms were observed and their allelic distribution was investigated. In our study sample, carriers of the C allele of the IVS3+43C --> T polymorphism were more prevalent in the group of AD patients than in healthy controls, while another IVS2-150A --> G polymorphism did not show a significant association with AD. The CC genotype of the IVS3+43C --> T polymorphism was associated with an increased 24S-hydroxycholesterol/cholesterol ratio in the CSF of AD patients. Our results indicate that the CYP46 gene locus may predispose to AD by increasing the 24S-hydroxycholesterol/cholesterol ratio in the brain.

Polymorphisms of the gene encoding the inflammatory cytokine interleukin-6 determine the magnitude of the increase in soluble interleukin-6 receptor levels in Alzheimer's disease. Results of a pilot study

Interleukin-6 (IL-6) is a multifunctional cytokine involved in the pathogenesis of Alzheimer's disease (AD). The effects of IL-6 are mediated through a specific receptor complex made up of a ligand binding glycoprotein (gp80 or IL-6R) and a signal transducing glycoprotein (gp130). Conflicting results have been reported concerning altered IL-6 or soluble IL-6R (sIL-6R) levels in serum and CSF in AD. This study investigated whether genetic heterogeneity determines the magnitude of the difference in IL-6 and sIL-6R levels in AD. Fifty-eight AD patients and 25 control subjects were included. Plasma and CSF IL-6 and sIL-6R levels were measured and the IL-6 variable number of number repeats ( IL-6vntr) and IL-6 promoter ( IL-6prom) genotypes were determined. sIL-6R levels in plasma and CSF were higher in AD patients than in control subjects. This elevation was striking among non-carriers of the IL-6vntr*C allele and among subjects homozygous for the IL-6prom*C allele whereas no difference in plasma and CSF sIL-6R levels was observed among carriers of the IL-6vntr*C allele and among subjects with the IL-6prom*CG and IL-6prom*GG genotypes. We conclude that plasma and CSF levels of sIL-6R are significantly increased in AD patients and that the magnitude of increase is determined by the IL-6 genotype.

Genetic variations and humoral immune responses to myelin oligodendroglia glycoprotein in adult phenotypes of X-linked adrenoleukodystrophy

The lack of phenotype/genotype association in X-linked adrenoleukodystrophy (X-ALD) has prompted the search for disease modifying factors. We previously demonstrated increased serum antibody responses against myelin oligodendrocyte glycoprotein (MOG) in various clinical phenotypes of X-ALD allowing speculations that myelin specific humoral immune responses might be involved in phenotype generation of X-ALD. In the present study, we investigated the possible association of (1) a naturally occurring variable number tandem repeat (vntr) polymorphism (C allele) in the 3' flanking region of the interleukin-6 gene (IL-6), previously demonstrated to modify the course of Alzheimer's disease, systemic lupus erythematodes and Multiple Sclerosis (MS), (2) a tetranucleotide repeat polymorphism (TAAA)(n) in the 3' flanking region of the MOG gene and (3) HLA class II alleles with adult clinical phenotypes and serum antibody responses to MOG in 70 adult X-ALD patients. HLA class II alleles, (TAAA)(n) MOG gene polymorphisms, and IL-6 C allele were not associated with clinical phenotypes. Anti-MOG antibodies were detectable in 17/54 X-ALD patients (31.5%). Anti-MOG antibodies were associated with the 226 bp (TAAA)(n) MOG gene polymorphism but not with distinct clinical phenotypes.

Lifetime depressive and somatic symptoms as preclinical markers of late-onset depression

BACKGROUND

Several risk factors of depression, i. e., female gender and life-stress, have been identified. Few studies have focussed on symptoms as preclinical markers of depression. In these studies current symptoms like dysphoria, tiredness and increased appetite predicted later depression. Even though of possible interest for treatment, no study focussed on lifetime symptoms as preclinical markers of depression. Consequently, we examined lifetime depressive and somatic symptoms with respect to later development of late-onset depression.

METHODS

664 non-depressed elderly subjects without lifetime diagnoses of depression at the initial examination were selected for a prospective follow-up study (mean follow-up +/- SD: 5.02 +/- 2.44 years). 51 subjects (mean age +/- SD: 66.6 +/- 11.3) developing late-onset depression (defined as depression starting after age 60) were compared to those remaining non-depressed (mean age +/- SD: 59.1 +/- 16.0) during follow-up using the CIDI. To determine the influence of lifetime symptoms on the development of depression, chi-square statistics and multivariate logistic regression analyses were performed.

RESULTS

The following symptoms being present over a period longer than two weeks were individual preclinical markers of late-onset depression: dysphoria, increased appetite, insomnia, lack of energy, morning depth, lack of joy and interest, inferiority feeling, lack of self-confidence, poor concentration, indecisiveness, thinking about death, wish to die and joint pain. The most important symptoms elevating the risk of late-onset depression in a multivariate model were lack of joy and interest, poor concentration, increased appetite, lack of energy and joint pain.

CONCLUSIONS

Different symptoms can be used individually and in combination to predict later depression. This might allow early treatment.

Association of an interleukin-1beta gene polymorphism at position -511 with Alzheimer's disease

Inflammation is thought to promote neuronal cell death in Alzheimer's disease (AD). The proinflammatory interleukin-1 is a main component in inflammatory pathways and is overexpressed in the brain of AD patients. Investigation of different polymorphisms in the interleukin-1 genes (IL-1alpha -889, IL-1beta -511, IL-1beta +3953) revealed associations between specific alleles and AD in that they increased the risk or modified the age at onset of AD. However, there are controversial findings from other studies which revealed no significant associations between these polymorphisms and AD; thus further evaluation of the association of IL-1 gene polymorphisms with AD and their role in pathogenesis is needed. In this study we examined the distribution of the IL-1beta -511 alleles in AD patients and a control sample of healthy individuals. An additional control population of non-demented depressive inpatients was recruited to exclude a confounding bias. The cerebrospinal fluid (CSF) levels of Abeta42 in AD patients were investigated to assess the influence of IL-1beta -511 genotypes. We found no significant association of the IL-1beta -511 polymorphism with AD, suggesting that the IL-1beta -511 polymorphism is no risk factor for AD. However, we found the Abeta42 CSF levels to be lower in carriers of the IL-1beta CC-genotype compared to carriers of the T-allele. Even though IL-1beta -511 polymorphism did not influence the risk of AD it might have a pathophysiological influence on the disease process.

Identification of a single nucleotide polymorphism in the choline acetyltransferase gene associated with Alzheimer's disease

The dysfunction of the cholinergic system in Alzheimer's disease (AD) supports the hypothesis that a decline in choline acetyltransferase (ChAT) activity in memory as well as in cognitive functions in AD might be functionally linked. To assess the physiological relevance of an allelic variation in the ChAT gene we investigated the presence of a possible polymorphism in AD patients and in elderly non-demented subjects as controls. By using polymerase chain reaction, single stranded conformation polymorphism or the LightCycler analysis we detected a single nucleotide polymorphism in the first common coding exon of the ChAT gene. We found a G --> A transition which occurred at position +4 of the coding sequence. The association between AD and the AA genotype or A alleles were found to be significant (odds ratio 3.7 and 2.4, respectively). The frequency of the AA genotype was three times higher in AD patients than in age-matched controls. This G --> A change raises the possibility that it may influence ATG usage resulting in attenuation of translation efficacy of ChAT messenger RNA. We suggest that such a polymorphism might be one of the events conferring an increased risk for deterioration of memory and cognition functions in AD.

Novelty detection and repetition suppression in a passive picture viewing task: a possible approach for the evaluation of neuropsychiatric disorders

The applicability of functional magnetic resonance imaging (fMRI) in patients with Alzheimer's disease (AD) or schizophrenia is frequently limited by cognitive impairment, which prevents the adequate execution of complex tasks. An experimental design that puts only minor demands on the patients' cognitive ability but engages disease-relevant brain structures would be of benefit. Novelty detection and repetition suppression are two basic components of memory that might be used to investigate specific brain areas under these conditions. Novelty detection has been related to hippocampal activation increases. Stimulus repetition related activation decreases (suppression) have been observed in the extrastriate cortex and have been related to perceptual priming. Both processes have been examined primarily in neuroimaging studies with complex cognitive tasks. We used event-related fMRI to investigate novelty- and repetition-related effects in an attended but passive picture-viewing task in healthy subjects. The differential activation, detected in the novel vs. repeated contrast, was located in the bilateral anterior hippocampus and in bilateral occipital and inferior-temporal areas. The hippocampal activation is of interest because medial temporal lobe lesions are key features in AD and schizophrenia. The repetition-related activation decreases in the extrastriate areas are of potential value in investigating the conflicting results regarding perceptual priming impairment in both disorders. Our results indicate that activation of disease-relevant brain regions under passive task conditions is possible. This might increase the utility of functional imaging in cognitively impaired patients.

The dichotomy of schizophrenia and affective disorders in extended pedigrees

The paper reports the first controlled family study investigating not only 1st but also 2nd and 3rd degree relatives of patients with schizophrenia by direct diagnostic interviews. Regardless of their degree of relationship, all biological relatives of the patients were found to be at an elevated risk of schizophrenia (5.0% in 1st, 3.1% in 2nd, 1.5% in 3rd degree relatives compared to 0.8% among controls). Schizoaffective and affective disorders have also been found to be more common in the three groups of relatives but without a monotone decline of prevalence rates across the groups. Other psychiatric disorders were not found to be at an elevated risk in relatives of patients compared to controls. Thus, our findings support the hypothesis that psychotic, as well as affective disorders, aggregate in families of individuals with schizophrenia.However, in our study, the risk of schizophrenia and the risk of affective disorders correlated. Particularly, the magnitude of the risk of schizophrenia among relatives of probands with schizophrenia varied with the occurrence of affective disorders in relatives. In relatives, the risk of schizophrenia was maximal in absence of a family history of affective disorder. This constellation holds true even if only families of index cases without any affective syndrome during lifetime are considered.

Fertility and number of children in patients with Alzheimer's disease

Oestrogen therapy has been suggested to have protective effects against Alzheimer's disease. The effects of natural exposure to oestrogen in cognitive disorders have rarely been studied. Assuming that nulliparous women have a higher exposure to natural oestrogen, it could be hypothesised that these women might have a lower risk of Alzheimer's disease than women who have had children. The fertility and number of children in 106 women with a diagnosis of Alzheimer's disease was examined and compared with that of 189 female subjects from two control groups with subjects without dementia. As additional control, the same comparisons were carried out for 40 male patients with Alzheimer's disease and 105 male control subjects. In female subjects, having had children was found to be associated with a diagnosis of Alzheimer's disease. This was not the case in male subjects. The number of children did not seem to affect the risk of Alzheimer's disease, neither in female nor in male subjects. Natural exposure to oestrogen seems to reduce the risk of Alzheimer's disease in women.

Possible influence of selection bias on gender differences in the risk of Alzheimer's disease

For the observation of a higher risk of Alzheimer's disease (AD) in women, causes like a general longer life expectancy of women, a longer lifespan of women with AD, a later age at onset and a lower level of education compared with men have been discussed. However, methodological artefacts could also contribute to the observed gender difference. Data from a comprehensive family study was re-evaluated, in which a gender difference in the risk of AD had been observed. Available relatives had been directly interviewed, information on unavailable ones was provided by thirds. A differential, gender specific participation led to the under-representation of older and demented men, creating a selection bias, that may be the cause for the observed gender difference in the risk of AD. Study methods must be taken into account when interpreting information on gender differences in the risk of AD.

Depression in Alzheimer's disease: is there a temporal relationship between the onset of depression and the onset of dementia?

Alzheimer's disease (AD) patients often present with concurrent major depression (MD). To investigate the reasons for this comorbidity, e.g. MD being a risk factor for AD, or both diagnoses having a common neurobiology, the temporal relationship between the first onset of AD and of MD during lifetime was investigated-57 out of 146 AD patients had a lifetime diagnosis of MD. The correlation between the ages at onset of MD and dementia was calculated. The incidence of MD in AD patients in several 5-year-intervals before and after the onset of AD was compared with the average incidence of MD in the present AD sample and with the expected incidence of MD in the general population. No significant correlation between the onset of AD and of MD could be found after controlling for age, gender and the Mini-Mental-State. However, the incidence of MD 5 years before and after the onset of AD significantly exceeded the expected incidences-MD is only partially related to AD. However, the increased incidence of MD within 5 years before and after the onset of dementia may indicate that a common neurobiological process causes cognitive decline and depression in a subsample of AD patients.

CSF tau protein phosphorylated at threonine 231 correlates with cognitive decline in MCI subjects

In this longitudinal study of 77 patients with mild cognitive impairment (MCI), the authors analyzed whether levels of tau protein phosphorylated at threonine 231 (p-tau(231)) in CSF correlate with progression of cognitive decline. High CSF p-tau(231) levels at baseline, but not total tau protein levels, correlated with cognitive decline and conversion from MCI to AD. Independently, old age and APOE-epsilon 4 carrier status were predictive as well. Our data indicate that an increased p-tau(231) level is a potential risk factor for cognitive decline in patients with MCI.

Test-retest reliability of self-reported age at onset of selected psychiatric diagnoses in general health care

OBJECTIVE

To investigate reliability of self-reported age at onset of frequent mental disorders and its association with patient and disorder characteristics.

METHOD

A total of 1031 primary care patients with at least one lifetime psychiatric diagnosis were asked to report age at onset of their disorders at baseline and after 1 year. Intraclass correlation coefficients (ICC) for age at onset information were calculated for individual disorders.

RESULTS

ICC were high and lay between 0.6790 (generalized anxiety disorder) and 0.7977 (dysthymia). Factors associated with reliability are different for different disorders: gender for depressive episodes, gross national product per year per inhabitant for dysthymia, age for pain disorder, years of formal education for dysthymia, generalized anxiety disorder, and agoraphobia, and number of lifetime diagnoses for depression and agoraphobia.

CONCLUSION

Self-reported age at onset is reliable. Further research on factors associated with reliability should focus on interview conditions and subject parameters during interview.

Cerebrospinal fluid levels of beta-amyloid(42) in patients with Alzheimer's disease are related to the exon 2 polymorphism of the cathepsin D gene

The intracellular aspartyl protease cathepsin D (catD) is involved in such Alzheimer's disease (AD)-related processes as the activation of the endosomal/lysosomal system and the cleavage of the amyloid precursor protein into amyloidogenic components, which may initiate neurodegeneration. A non-synonymous polymorphism (exon 2, C to T exchange leading to ala-->val substitution) of the gene encoding catD (CTSD) was previously associated with AD, in that the T allele increased the risk for AD. To investigate whether the T allele is associated with disease-related traits, we measured the concentration of the amyloid beta-peptide 1-42 (Abeta(42)) and 1-40 (Abeta(40)) in patients and control subjects. The T allele of the CTSD genotype was associated with a 50% decrease in Abeta(42) levels in the cerebrospinal fluid. Thus, we demonstrate a significant impact of the CTSD genotype on Abeta(42) levels in the cerebrospinal fluid of AD patients and underpin the importance of the validation of susceptibility genes by examining their potential pathophysiological relevance.

[Chronic course and psychosocial disability caused by depressive illnesses in general practice patients during a one year period. Results of a study by the World Health Organization]

As part of an international WHO study on psychological disorders in primary health care, patients were examined for mental disorders and especially depression and social disability in the course of 1 year. Depression is common in primary care (8.6%) and frequently associated with recurring or chronic courses (33.3%). Depression at baseline leads to a 100% increase of lost working days (3.2 per month) 1 year later as compared to patients without depression (1.7). The diagnosis of depression at baseline poses a greater risk for a relevant and lasting psychosocial disability (28.2%) than e.g. chronic somatic illnesses (8.6%). Even the diagnosis of a subthreshold depression leads comparatively to a higher degree of psychosocial disability (15.6% of patients) and days of absenteeism at work during the last month (2.9 days).

The insulin gene VNTR polymorphism in Alzheimer's disease: results of a pilot study

Insulin (INS) and insulin-like growth factors include different polypeptides involved in growth and development. Possibly they play a role in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease (AD). A variable number of tandem repeats (VNTR) polymorphism at the human INS 5'-flanking region consisting of three distinct allele classes has been shown to influence the tissue-specific expression of INS and the insulin-like growth factor 2 (IGF-2). Since alterations in the expression of INS or IGF-2 might be relevant in AD, we investigated the association between the INS VNTR polymorphism and the risk for AD. We found no association between the INS VNTR genotype and the risk for AD (p = 0.873). However, survival analysis revealed that class III homozygotes of the INS VNTR polymorphism had an earlier initial onset in patients suffering from early AD (p = 0.002). Our preliminary results suggest, that genetically determined alterations of the INS/IGF-2 metabolism might modify the course of AD. Further studies are warranted to confirm these data in larger study samples.

Regional N-acetylaspartate reduction in the hippocampus detected with fast proton magnetic resonance spectroscopic imaging in patients with Alzheimer disease

OBJECTIVE

To detect regional metabolic changes that resemble the expected spatial pattern of neuronal loss in patients with Alzheimer disease (AD).

METHODS

Thirty-four patients with AD and 22 healthy control subjects were included in the study. Single-slice fast proton spectroscopic imaging was performed in parallel angulation to the temporal lobes. Proton spectra were selected from the hippocampus, the lateral temporal lobe, and the occipital lobe of both hemispheres to determine metabolite concentration of N-acetylaspartate (NAA), total creatine (tCr), including phosphocreatine and creatine, and choline-containing compounds (Cho). The metabolic ratios of NAA/tCr and Cho/tCr were calculated and compared between patients with AD and healthy volunteers.

RESULTS

The NAA/tCr ratios were significantly reduced in the left (F(1,1) = 4.34, P =.04) and right hippocampus (F(1,1) = 9.96, P =.003) in patients with AD. The Cho/tCr ratios remained unchanged in both hippocampi. There was no significant change of either NAA/tCr or Cho/tCr in the lateral temporal and occipital lobes of patients with AD.

CONCLUSION

This study provides evidence that fast proton spectroscopic imaging may detect the regional pattern of disturbed neuronal integrity in patients with AD with high spatial resolution in a short acquisition time.

Risk factors for new depressive episodes in primary health care: an international prospective 12-month follow-up study

BACKGROUND

Studies that examined community samples have reported several risk factors for the development of depressive episodes. The few studies that have been performed on primary care samples were mostly cross-sectional. Most samples had originated from highly developed industrial countries. This is the first study that prospectively investigates the risk factors of depressive episodes in an international primary care sample.

METHODS

A stratified primary care sample of initially non-depressed subjects (N = 2,445) from 15 centres from all over the world was examined for the presence or absence of a depressive episode (ICD-10) at the 12 month follow-up assessment. The initial measures addressed sociodemographic variables, psychological/psychiatric problems and social disability. Logistic regression analysis was carried out to determine their relationship with the development of new depressive episodes.

RESULTS

At the 12-month follow-up, 44% of primary care patients met ICD-10 criteria for a depressive episode. Logistic regression analysis revealed that the recognition by the general practitioner as a psychiatric case, repeated suicidal thoughts, previous depressive episodes, the number of chronic organic diseases, poor general health, and a full or subthreshold ICD-10 disorder were related to the development of new depressive episodes.

CONCLUSIONS

Psychological/psychiatric problems were found to play the most important role in the prediction of depressive episodes while sociodemographic variables were of lower importance. Differences compared with other studies might be due to our prospective design and possibly also to our culturally different sample. Applied stratification procedures, which resulted in a sample at high risk of developing depression, might be a limitation of our study.

Psychiatric disorders in relatives of subjects with Alzheimer's disease. No evidence for common genetic risk factors

INTRODUCTION

The clustering of two or more disorders in the same family might indicate the presence of common genetic risk factors. The prevalence of various psychiatric disorders in relatives of Alzheimer's disease (AD) patients has rarely been investigated. Consequently, family study data were reinvestigated to assess, if there are indications for an overlap of genetic risk factors of AD and other psychiatric disorders.

METHOD

Family history information on 2964 living and deceased first-degree relatives of 146 AD patients, 168 patients with major depression (MD) and 136 control subjects were obtained by at least one informant. Of the living relatives, 49.2 % could also be interviewed. Best-estimate lifetime diagnoses were made on all available information. Lifetime prevalences of psychiatric disorders were compared in relatives of AD patients, of MD patients and of control subjects using chi(2) statistics. Cox proportional hazards regression analyses were additionally performed to control for the relative's age, gender and source of information (interview vs. family history information).

RESULTS

Relatives of AD patients had no increased risk of other psychiatric disorder compared with relatives of the comparison groups.

CONCLUSION

AD is genetically distinct from other psychiatric disorders, i. e., schizophrenia, anxiety, obsessive-compulsive, somatoform disorders, alcoholism, substance abuse or dependency.

Physical disorders and causes of death in relatives of Alzheimer's disease patients

BACKGROUND

Genetic risk factors are important in Alzheimer's disease (AD). These risk factors might also predispose for other disorders. This might lead to a familial coaggregation of AD and other disorders, e.g. Down's syndrome or Parkinson's disease. In the present study the risk of physical disorders in relatives of AD patients, of depressed patients and of control subjects were compared.

METHODS

Family history and, if possible, interview information on physical disorders and causes of death in relatives of 146 patients with AD, 168 patients with major depression (MD) and 136 controls was collected. Statistical comparisons were performed using chi-square tests and, if necessary, logistic regression analysis accounting for age, gender and interview status.

RESULTS

In contrast to our hypotheses, there was no increased risk of cerebrovascular disease, Down's syndrome, haematological malignancies or Parkinson's disease in relatives of AD patients compared with relatives of patients with MD and of controls. The explorative analysis revealed that congenital malformations, i.e. malformations of the heart or of the extremities, were slightly increased in relatives of AD patients. Relatives of patients with AD or MD were at increased risk of dying as a result of accidents, in most cases falls in advanced age, and relatives of patients with MD were at slightly increased risk of dying from gastroenterologic diseases, in most cases complications of peptic ulcers.

CONCLUSION

The results do not support a major overlap between the genetic risk of AD and the genetic risk of cerebrovascular disease, Down's syndrome, haematological malignancies or Parkinson's disease. The finding of an increased risk of congenital malformations in relatives of AD patients needs further replication before it can be stated. The increased risk of dementia or depression with cognitive impairment in elderly relatives of patients with AD or MD increases the risk of accidents like falls. The genetic risk of depression in relatives of patients with MD could have a negative influence on the prognosis of peptic ulcera.

Cathepsin D: screening for new polymorphisms using single-strand conformation polymorphism analysis

Cathepsin D (CTSD) is a lysosomal protease involved in the pathogenesis of several diseases such as breast cancer and possibly Alzheimer's disease (AD). Previous findings revealed a significant association between the T allele of the 224 C/T (A58V) polymorphism in exon 2 of the CTSD gene and late onset AD. The exonic regions of the CTSD gene were screened for further polymorphic variations using polymerase chain reaction and single-strand conformation polymorphism analysis. In addition to the known 224 C/T polymorphism and two silent mutations in exons 3 and 4 we detected two new polymorphisms in introns 5 and 8. Combination of these sequence variations results in three different haplotypes; one of these haplotypes is due to the new polymorphism in intron 5. We detected no further missense mutations except for the known 224 C/T polymorphism in exon 2. Thus, if sequence variations within the CTSD gene influence the risk for various diseases, the pathogenic mechanism is likely to be linked to the amino acid substitution in the profragment of CTSD.

24S-hydroxycholesterol in cerebrospinal fluid is elevated in early stages of dementia

The brain is the most cholesterol-rich organ in the human body. Accumulation of excess cholesterol in hippocampal neurons promotes the cleavage of the amyloid precursor protein (APP) into amyloidogenic components with the consequence of the acceleration of neuronal degeneration. Conversion of cholesterol to 24S-hydroxycholesterol mediated by cholesterol 24S-hydroxylase (CYP46) is the major pathway for the elimination of brain cholesterol and the maintenance of brain cholesterol homeostasis. We examined whether cerebrospinal fluid (CSF) 24S-hydroxycholesterol levels differ between patients with dementia, patients with mild cognitive impairment (MCI), and cognitively intact control subjects. Plasma and CSF concentrations of 24S-hydroxycholesterol and cholesterol in 32 patients with Alzheimer's disease (AD), 11 patients with vascular dementia, seven patients with MCI, and seven cognitively intact control subjects were measured by combined gas-chromatography/mass spectrometry. We show elevated concentrations of 24S-hydroxycholesterol in the CSF of AD patients and we interpret this finding as a consequence of increased cholesterol turnover in the central nervous system during neurodegeneration. The observed influence of the apolipoprotein E epsilon4 (APOE4) allele on CSF 24S-hydroxycholesterol concentrations with a gene-dosage effect suggests the existence of a link between the AD risk factor APOE4 and CNS cholesterol metabolism. The elevation of CSF 24S-hydroxycholesterol appears to occur early in the disease process, since patients with mild cognitive impairment had also increased CSF concentrations of this compound. We believe that the CSF concentration of 24S-hydroxycholesterol is altered in AD-related neurodegeneration and thus, CSF 24S-hydroxycholesterol may be a marker for monitoring the onset and progression of the disease.

Gender differences of depressive symptoms in depressed and nondepressed elderly persons

OBJECTIVES

Women suffer more frequently from major depression and depressive symptoms than men. The somatic and the atypical subtype of depression seem to be more prevalent in women. However, few studies investigated gender differences of depressive symptoms in the elderly. These gender differences in the elderly will be investigated in the present study.

METHODS

In the course of a family study 236 subjects with a lifetime diagnosis of major depression aged > 50 years and 357 control subjects from the general population matched for age and gender were questioned using the Composite International Diagnostic Interview (CIDI). Chi-square tests were used to compare the individual depressive symptoms between men and women and logistic regression analyses were performed to account for the subjects' age, cognitive performance, family and employment status.

RESULTS

Women in the general population suffered from more depressive symptoms than men and had more appetite disturbance and joylessness. These gender differences could be entirely explained by gender differences in the family and the employment status. Men and women with a major depressive disorder presented with a distinct profile of symptoms that could not be explained by psychosocial factors: elderly depressed women presented with more appetite disturbances and elderly depressed men with more agitation.

CONCLUSION

Major depression in the elderly presents with partially different symptoms in men and women. The results suggest that the gender differences in the symptoms of major depression in the elderly reflect gender differences in the perception and the expression of depressive syndromes.