Biomedical subjects

Bengt Winblad

Publications and source records attributed to Bengt Winblad.

At least 37 records · Page 2Linked to original sources

PubMed2006

Antibody-bound amyloid precursor protein upregulates ornithine decarboxylase expression.

Alzheimer's disease is a neurodegenerative disorder characterised by extracellular accumulation of the Abeta peptide, derived from the amyloid precursor protein (APP). The function of APP as a cell surface receptor was examined by ligand-mimicking using an antibody against the APP extracellular domain. Alterations in gene expression evoked by antibody-bound APP were analysed using human pathway-finder gene arrays and the largest change in expression levels was found for ornithine decarboxylase (ODC). These results were confirmed by Western blotting which showed even higher upregulation on the protein level. APP knockdown by RNAi verified that upregulation of ODC was APP-mediated. This APP signalling event did not require gamma-secretase cleavage, as it was independent of the presence of presenilin-1 or -2. The induced ODC expression was rapid and biphasic, resembling growth-factor stimulated signalling events. This study shows that antibody-bound APP leads to altered gene expression that may be relevant to AD.

Amyloid beta-Protein Precursor↗

PubMed2006

alpha-Melanocyte-stimulating hormone is neuroprotective in rat global cerebral ischemia.

The aim of the study was to investigate the effects of alpha-melanocyte-stimulating hormone (alpha-MSH), a tridecapeptide derived from proopiomelanocortin (POMC), on the neurodegeneration following global cerebral ischemia and reperfusion in the rat. The biological activities of alpha-MSH include inhibition of inflammatory responses and anti-pyretic effects. Male Sprague-Dawley rats were subjected to four-vessel occlusion (4-VO) global cerebral ischemia followed by reperfusion, and treated with alpha-MSH (intraperitoneally, i.p.) at 30 min, and 24, 48, 72 and 96 h post-ischemia. Stereological quantification of the pyramidal cells in the CA1 area of the hippocampus showed that the number of viable neurons in ischemic rats was 96,945+/-18,610 (means+/-SD) as compared to 183,156+/-49,935 in sham-operated rats (P<0.05). The number of viable neurons after treatment of ischemic rats with alpha-MSH was 162,829+/-34,757, i.e. significantly different from the number of viable neurons in ischemic rats injected with saline (P<0.01). Astrocyte proliferation due to the ischemic insult was markedly reduced by the treatment with alpha-MSH, and the loss in body weight was reduced by alpha-MSH. In conclusion, post-ischemic administration of alpha-MSH was found to provide neuroprotection in the CA1 pyramidal cell layer in the hippocampus, concomitant with a reduction in glial activation, indicating that alpha-MSH or mimetics thereof may have a potential in the treatment of stroke or other neurodegenerative diseases. Further studies will be required to define the post-ischemic time window for administration of alpha-MSH.

Animals↗

PubMed2006

Influence of differential housing on emotional behaviour and neurotrophin levels in mice.

Environmental enrichment condition (EC) induces profound behavioural, neurochemical and neuroanatomical changes. Increasing evidence has shown that the hippocampus, which is implicated in a range of cognitive functions, including learning and memory, is one of the most susceptible brain areas to the effects of enriched rearing. Recent work also suggests that the hippocampus is functionally segregated; lesion studies have shown that the dorsal hippocampus is important for spatial learning, whereas the ventral part is critical in emotional behaviour in rats. We investigated the effects of differential housing environments on anxiety-related behaviour and neurotrophin levels in dorsal and ventral hippocampus, and other brain regions. Ninety-six male and female C57BL/6 mice were reared in EC or standard housing condition (SC) for 4 months after weaning. Thereafter sixty-four animals were tested in the elevated plus-maze, open-field, novel-objects exploration and food neophobia. Thirty-two animals remained as untested. Subsequently, brain nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) were analysed in selected brain regions of the tested and non-tested animals. Differential housing influenced anxiety-related behaviour in the plus-maze and brain neurotrophins. Baseline levels of BDNF and NGF protein were differently distributed in dorsal and ventral parts of hippocampus in both male and female mice, with levels in the dorsal hippocampal being consistently higher than those in ventral hippocampus. Exposure to behavioural testing induced complex changes on neurotrophin levels in selected brain regions. This study demonstrates for the first time the differential distribution of normal levels of neurotrophin protein in dorsal and ventral hippocampus in mice, and these levels can be affected by environmental enrichment and have an impact on emotional behaviour.

Analysis of Variance↗

PubMed2006

Determinants of costs of care for patients with Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD), the most common cause of dementia, is a major cause of disability and care burden in the elderly. This study aims to estimate the costs of formal and informal care and identity determinants of care costs. MATERIALS AND METHODS: Two hundred and seventy-two (AD) patients and their caregivers were recruited among patients attending regular visits at six memory clinic in Sweden, Denmark, Norway and Finland. Patients with a diagnosis of AD and with an identifiable primary caregiver were eligible for inclusion. Data was collected by questionnaires at baseline, and at scheduled follow-up visits after 6 months and again after 12 months. Cognitive function was assessed with the Mini Mental State Examination (MMSE) and behavioural disturbances were measured using a brief version of the neuropsychiatric inventory (NPI). RESULTS: Total annual costs were on average 172,000 SEK, ranging from 60,700 SEK in mild dementia to 375,000 SEK in severe dementia. Costs for community care (special accommodation, home help, etc.) constituted about half of total costs of care and increase sharply with increasing cognitive impairment. Informal care costs, valued at the opportunity cost of the caregiver's time, make up about a third of total costs and also increased significantly with disease severity. Medical care costs (inpatient care, outpatient care, pharmaceuticals), on the other hand, were not significantly related to disease severity. Regression analysis confirmed a strong association between costs and cognitive function, between patients as well as within patients over time. There was also a significant influence on costs from behavioural disturbances. Sensitivity analysis showed that the method chosen to value informal care can have considerable impact on results. CONCLUSIONS: Costs of care in patient with AD are high and related to dementia severity as well as presence of behavioural disturbances. The cost estimates presented have implications for future economic evaluation of treatments for Alzheimer's disease.

Aged↗

PubMed2006

Differential role of Presenilin-1 and -2 on mitochondrial membrane potential and oxygen consumption in mouse embryonic fibroblasts.

Increasing evidence indicates that mitochondrial alterations contribute to the neuronal death in Alzheimer's disease (AD). Presenilin 1 (PS1) and Presenilin 2 (PS2) mutations have been shown to sensitize cells to apoptosis by mechanisms suggested to involve impaired mitochondrial function. We have previously detected active gamma-secretase complexes in mitochondria. We investigated the impact of PS/gamma-secretase on mitochondrial function using mouse embryonal fibroblasts derived from wild-type, PS1-/-, PS2-/- and PS double knock-out (PSKO) embryos. Measurements of mitochondrial membrane potential (DeltaPsim) showed a higher percentage of fully functional mitochondria in PS1-/- and PSwt as compared to PS2-/- and PSKO cells. This result was evident both in whole cell preparations and in isolated mitochondria. Interestingly, pre-treatment of isolated mitochondria with the gamma-secretase inhibitor L-685,458 resulted in a decreased population of mitochondria with high DeltaPsim in PSwt and PS1-/- cells, indicating that PS2/gamma-secretase activity can modify DeltaPsim. PS2-/- cells showed a significantly lower basal respiratory rate as compared to other cell lines. However, all cell lines demonstrated competent bioenergetic function. These data point toward a specific role of PS2/gamma-secretase activity for proper mitochondrial function and indicate interplay between PS1 and PS2 in mitochondrial functionality.

Adenosine Triphosphate↗

PubMed2006

Anaemia increases the risk of dementia in cognitively intact elderly.

Although cross-sectional studies found an association between anaemia and dementia, longitudinal studies provided contradictory results. We hypothesize that anaemia might increase the risk of developing dementia because of chronic brain hypo-oxygenation. Using baseline data from a community-based longitudinal study, the Kungsholmen Project, Stockholm, Sweden, we clinically followed 1435 non demented subjects aged 75-95 years for 3 years to detect incident dementia cases (DSM-III-R criteria). Subjects that fulfilled WHO criteria for anaemia, baseline haemoglobin concentration; 130 g/L (men) and 120 g/L (women), had a higher hazard ratios (HR) of developing dementia 3 years later (HR 1.6, 95% CI: 1.1-2.4). In persons with good baseline cognition (MMSE>or=26, n=1139), the association was stronger and still significant after adjustments for conditions potentially related to anaemia and dementia, such as chronic diseases, inflammatory markers, and indicators of nutritional status. The HR was increased even when different haemoglobin cut offs for anaemia definition were used. Thus, anaemia is suggested to be a new potential modifiable risk factor for dementia.

Aged↗

PubMed2006

Risk score for the prediction of dementia risk in 20 years among middle aged people: a longitudinal, population-based study.

BACKGROUND: Several vascular risk factors are associated with dementia. We sought to develop a simple method for the prediction of the risk of late-life dementia in people of middle age on the basis of their risk profiles. METHODS: Data were used from the population-based CAIDE study, which included 1409 individuals who were studied in midlife and re-examined 20 years later for signs of dementia. Several midlife vascular risk factors were studied to create the scoring tool. The score values were estimated on the basis of beta coefficients and the dementia risk score was the sum of these individual scores (range 0-15). FINDINGS: Occurrence of dementia during the 20 years of follow-up was 4%. Future dementia was significantly predicted by high age (> or = 47 years), low education (< 10 years), hypertension, hypercholesterolaemia, and obesity. The dementia risk score predicted dementia well (area under curve 0.77; 95% CI 0.71-0.83). The risk of dementia according to the categories of the dementia risk score was 1.0% for those with a score of 0-5, 1.9% for a score of 6-7, 4.2% for a score of 8-9, 7.4% for a score of 10-11, and 16.4% for a score of 12-15. When the cut-off of 9 points or more was applied the sensitivity was 0.77, the specificity was 0.63, and the negative predictive value was 0.98. INTERPRETATION: The dementia risk score is a novel approach for the prediction of dementia risk, but should be validated and further improved to increase its predictive value. This approach highlights the role of vascular factors in the development of dementia and could help to identify individuals who might benefit from intensive lifestyle consultations and pharmacological interventions.

Area Under Curve↗

PubMed2006

Of mice and men: more neurobiology in dementia.

PURPOSE OF REVIEW: An increasing number of genetically modified mouse models are designed and used in the field of Alzheimer disease research. This review aims to offer a general view of the existing transgenic mouse lines and to discuss their relevance and limitations. RECENT FINDINGS: Potential therapeutic targets have been identified in rodent models of Alzheimer disease. Although important steps towards obtaining a safe vaccine to prevent amyloid plaque formation have been made, further evaluations and the use of intermediate models are considered a necessity. SUMMARY: More than 18 million people worldwide are suffering from Alzheimer disease, the most common dementing disorder in humans. Transgenic lines have been created in order to understand the underlying mechanisms of Alzheimer disease and to find a cure. None of the available models completely recapitulates the characteristics of human pathology, but they provide valuable information on different pathogenic pathways involved. New therapeutic approaches and improvement of current strategies can be obtained from the use of Alzheimer animal models.

Alzheimer Disease↗

PubMed2006

Periodontal disease in the oldest-old living in Kungsholmen, Sweden: findings from the KEOHS project.

AIMS: The Kungsholmen Elders Oral Health Study evaluated the oral health status of generally healthy, community-dwelling persons aged 80 years and over living in Stockholm, Sweden. This paper reports periodontal disease findings and evaluates the distribution by sociodemographic factors. METHODS: Eligible persons were identified through the Kungsholmen Project, an ongoing, longitudinal, population-based study of older adults. A total of 121 study subjects received a periodontal examination. RESULTS: The mean pocket probing depth was 2.6 mm and the mean clinical attachment loss was 3.7 mm. Gingival bleeding was common. Over half of all study participants met the criteria used for "serious periodontitis" (SP). In the best fit adjusted odds ratio (OR) model, males were 3.1 times more likely than females to have "SP" (OR=3.1, 95% CI 1.2, 8.0), a statistically significant observation. A sub-analysis of the differences in proportion of participants with SP revealed that the difference by sex also increased by age. CONCLUSIONS: These findings document the substantial and ongoing impact of periodontal disease in a sample of generally healthy, community dwelling older adults and underscore the importance of continued periodontal disease prevention and treatment in the oldest-old.

Age Factors↗

PubMed2006

Cerebrovascular disease, APOE epsilon4 allele and cognitive decline in a cognitively normal population.

OBJECTIVES: To investigate whether cerebrovascular disease (CVD) and apolipoprotein E (APOE) epsilon4 allele were associated with cognitive decline and whether the relationship between CVD and cognitive decline varied by APOE epsilon4 status. METHODS: A total of 809 cognitively normal community-dwelling residents aged >75 years were followed to detect subjects with cognitive decline, defined as follow-up. Mini-mental state examination (MMSE) score was >10% decease of the baseline score. Logistic and multinomial logistic models were developed to estimate odds ratio (OR) and 95% confidence interval (CI) of cognitive decline related to a history of CVD and APOE epsilon4 by taking into account major potential confounders including baseline MMSE score. RESULTS: During the mean 3.5 years of follow-up, 190 subjects experienced cognitive decline. Multi-adjusted ORs (95% CIs) of overall cognitive decline were 2.27 (1.23-4.17) for CVD and 1.69 (1.13-2.54) for APOE epsilon4, but no interaction was detected. Multinomial logistic analysis led to the CVD-related ORs of 1.42 (0.75-2.67) for cognitive decline without progression to dementia and 3.41 (1.55-7.55) for the decline progressing to dementia; similar analysis from a separate model led to adjusted OR of 2.28 (0.88-5.87; p=0.09) for the decline progressing to Alzheimer's disease. The risk effects of CVD on cognitive decline with progression to dementias were statistically significant mainly among individuals without APOE epsilon4 allele. CONCLUSIONS: CVD is a major risk factor for cognitive decline associated with progression to dementia and Alzheimer's disease. There appears no interaction between CVD and APOE epsilon4 on cognitive decline in very old people.

Aged↗

PubMed2005

Work situation of registered nurses in municipal elderly care in Sweden: a questionnaire survey.

BACKGROUND: Organizational changes have occurred in municipal elderly care in Sweden during the past decades. The 'Adel' reform transferred responsibility for the care of older persons from the county councils to the municipalities. Furthermore, the specialisation in dementia care divided elderly care into two groups: dementia and general care. This change has had a significant impact on the work situation of registered nurses (RNs). AIM: The main focus was to describe RNs' work situation and their characteristics in municipal elderly care. Another aim was to compare RNs working solely in dementia care with those working in general care of older persons with diverse diagnoses. DESIGN: A non-experimental, descriptive design with a survey research approach was used. SETTINGS: Sixty special housing units with underlying units including those offering daytime activities in a large city in the middle of Sweden. PARTICIPANTS: The number of participating RNs was a total of 213, with a response rate of 62.3%. Of the 213 RNs, 95 (44.6%) worked in dementia care, and 118 (55.4%) in general care. METHOD: A questionnaire survey. RESULTS: The results indicated high levels of time pressure in both groups. Greater knowledge and greater emotional and conflicting demands were found in dementia care. The majority perceived a greater opportunity to plan and perform daily work tasks than to influence the work situation in a wider context. Support at work was perceived as generally high from management and fellow workers and higher in dementia care. CONCLUSION: It is important to decrease RNs' time pressure and increase their influence on decisions made at work.

Adult↗

PubMed2005

Neurotrophin levels and behaviour in BALB/c mice: impact of intermittent exposure to individual housing and wheel running.

This study assessed the effects of intermittent individual housing on behaviour and brain neurotrophins, and whether physical exercise could influence alternate individual-housing-induced effects. Five-week-old BALB/c mice were either housed in enhanced social (E) or standard social (S) housing conditions for 2 weeks. Thereafter they were divided into six groups and for 6 weeks remained in the following experimental conditions: Control groups remained in their respective housing conditions (E-control, S-control); enhanced individual (E-individual) and standard individual (S-individual) groups were exposed every other day to individual cages without running-wheels; enhanced running-wheel (E-wheel) and standard running-wheel (S-wheel) groups were put on alternate days in individual running-wheel cages. Animals were assessed for activity in an automated individual cage system (LABORAS) and brain neurotrophins analysed. Intermittent individual housing increased behavioural activity and reduced nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) levels in frontal cortex; while it increased BDNF level in the amygdala and BDNF protein and mRNA in hippocampus. Besides normalizing motor activity and regulating BDNF and NGF levels in hippocampus, amygdala and cerebellum, physical exercise did not attenuate reduction of cortical NGF and BDNF induced by intermittent individual housing. This study demonstrates that alternate individual housing has significant impact on behaviour and brain neurotrophin levels in mice, which can be partially altered by voluntary physical exercise. Our results also suggest that some changes in neurotrophin levels induced by intermittent individual housing are not similar to those caused by continuous individual housing.

Analysis of Variance↗

PubMed2005

P70 S6 kinase mediates tau phosphorylation and synthesis.

Currently, we found that the 70-kDa p70 S6 kinase (p70S6K) directly phosphorylates tau at S262, S214, and T212 sites in vitro. By immunoprecipitation, p-p70S6K (T421/S424) showed a close association with p-tau (S262 and S396/404). Zinc-induced p70S6K activation could only upregulate translation of total S6 and tau but not global proteins in SH-SY5Y cells. The requirement of p70S6K activation was confirmed in the SH-SY5Y cells that overexpress wild-type htau40. Level of p-p70S6K (T421/S424) was only significantly correlated with p-tau at S262, S214, and T212, but not T212/S214, in Alzheimer's disease (AD) brains. These suggested that p70S6K might contribute to tau related pathologies in AD brains.

Alzheimer Disease↗

PubMed2005

CLAC binds to aggregated Abeta and Abeta fragments, and attenuates fibril elongation.

Deposition of amyloid beta-peptide (Abeta) into amyloid plaques is one of the invariant neuropathological features of Alzheimer's disease. Proteins that codeposit with Abeta are potentially important for the pathogenesis, and a recently discovered plaque-associated protein is the collagenous Alzheimer amyloid plaque component (CLAC). In this study, we investigated the molecular interactions between Abeta aggregates and CLAC using surface plasmon resonance spectroscopy and a solid-phase binding immunoassay. We found that CLAC binds to Abeta with high affinity, that the central region of Abeta is necessary and sufficient for CLAC interaction, and that the aggregation state of Abeta as well as the presence of negatively charged residues is important. We also show that this binding results in a reduced rate of fibril elongation. Taken together, we suggest that CLAC becomes involved at an intermediate stage in the pathogenesis by binding to Abeta fibrils, including fibrils formed from peptides with truncated N- or C-termini, and thereby slows their growth.

Alzheimer Disease↗

PubMed2005

Mental, physical and social components in leisure activities equally contribute to decrease dementia risk.

BACKGROUND: There is accumulating evidence in the literature that leisure engagement has a beneficial effect on dementia. Most studies have grouped activities according to whether they were predominantly mental, physical or social. Since many activities contain more than one component, we aimed to verify the effect of all three major components on the dementia risk, as well as their combined effect. METHODS: A mental, social and physical component score was estimated for each activity by the researchers and a sample of elderly persons. The correlation between the ratings of the authors and the means of the elderly subjects' ratings was 0.86. The study population consisted of 776 nondemented subjects, aged 75 years and above, living in Stockholm, Sweden, who were still nondemented after 3 years and were followed for 3 more years to detect incident dementia cases. RESULTS: Multi-adjusted relative risks (RRs) of dementia for subjects with higher mental, physical and social component score sums were 0.71 (95% CI: 0.49-1.03), 0.61 (95% CI: 0.42-0.87) and 0.68 (95% CI: 0.47-0.99), respectively. The most beneficial effect was present for subjects with high scores in all or in two of the components (RR of dementia = 0.53; 95% CI: 0.36-0.78). CONCLUSIONS: These findings suggest that a broad spectrum of activities containing more than one of the components seems to be more beneficial than to be engaged in only one type of activity.

Aged↗

PubMed2005

PTEN levels in Alzheimer's disease medial temporal cortex.

Phosphatase and tensin homologue deleted from chromosome 10 (PTEN) is a dual (protein tyrosine and lipid) phosphatase one of the functions of which is to dephosphorylate phosphatidylinositol 3,4,5-trisphosphate to phosphatidylinositol-3,4-biphosphate thereby inhibiting phosphoinositide-dependent kinase activation of the cell survival kinase Akt. Akt activity is up regulated in Alzheimer's disease (AD) brain in parallel to the progression of neurofibrillary pathology. The present study determined whether altered expression of PTEN occurs in Alzheimer's disease brain. Western immunoblotting revealed no significant changes of PTEN protein levels in nuclear and membrane fractions of medial temporal cortex from a series of Alzheimer's disease and control cases. Similarly, no changes in PTEN protein levels, as determined by dot-blotting, were seen in temporal cortex homogenates from a separate series of Alzheimer's disease and control brains. A small but significant decrease in the levels of Ser(380) p-PTEN was seen in homogenates of Alzheimer's disease temporal cortex. Immunohistochemistry revealed PTEN immunoreactivity in a number of brain structures including neurons, capillaries and structures resembling oligodendrocytes and astrocytes. The majority of temporal cortex pyramidal neurons (93-100%) were PTEN immunopositive. The Alzheimer's disease cases had significantly lower numbers of total ( approximately 12% loss, P<0.02) and PTEN immunopositive ( approximately 15% loss, P<0.01) pyramidal neurons as compared to the control cases.

Aged↗

PubMed2005

Effects of statins on microglia.

High serum cholesterol level has been shown as one of the risk factors for Alzheimer's disease (AD), and epidemiological studies indicate that treatment with cholesterol-lowering substances, statins, may provide protection against AD. An acute-phase reaction and inflammation, with increased levels of proinflammatory cytokines, are well known in the AD brain. Notably, there is evidence for antiinflammatory activities of statins, such as reduction in proinflammatory cytokines. Consequently, it is of interest to analyze the effects of statins on microglia, the main source of inflammatory factors in the brain, such as in AD. The aims of this study were to determine the effects of statins (atorvastatin and simvastatin) on microglial cells with regard to the secretion of the inflammatory cytokine interleukin-6 (IL-6) and cell viability after activation of the cells with bacterial lipopolysaccharides (LPS) or beta-amyloid1-40 (Abeta1-40) and in unstimulated cells. Cells of the human microglial cell line CHME-3 and primary cultures of rat neonatal cortical microglia were used. Incubation with LPS or Abeta1-40 induced secretion of IL-6, and Abeta1-40, but not LPS, reduced cell viability. Both atorvastatin and simvastatin reduced the basal secretion of IL-6 and the cell viability of the microglia, but only atorvastatin reduced LPS- and Abeta1-40-induced IL-6 secretion. Both statins potentiated the Abeta1-40-induced reduction in cell viability. The data indicate the importance of also considering the microglial responses to statins in evaluation of their effects in AD and other neurodegenerative disorders with an inflammatory component.

Amyloid beta-Peptides↗

PubMed2005

A unique gene expression signature discriminates familial Alzheimer's disease mutation carriers from their wild-type siblings.

Alzheimer's disease (AD) is a neurodegenerative disease with an insidious onset and progressive course that inevitably leads to death. The current diagnostic tools do not allow for diagnosis until the disease has lead to irreversible brain damage. Genetic studies of autosomal dominant early onset familial AD has identified three causative genes: amyloid precursor protein (APP), presenilin 1 and 2 (PSEN1 and PSEN2). We performed a global gene expression analysis on fibroblasts from 33 individuals (both healthy and demented mutation carriers as well as wild-type siblings) from three families segregating the APP(SWE), APP(ARC) and PSEN1 H163Y mutations, respectively. The mutations cause hereditary progressive cognitive disorder, including typical autosomal dominant AD. Our data show that the mutation carriers share a common gene expression profile significantly different from that of their wild-type siblings. The results indicate that the disease process starts several decades before the onset of cognitive decline, suggesting that presymptomatic diagnosis of AD and other progressive cognitive disorders may be feasible in the near future.

Alzheimer Disease↗