Genome sequencing analysis identifies new loci associated with Lewy body dementia and provides insights into its genetic architecture.

The genetic basis of Lewy body dementia (LBD) is not well understood. Here, we performed whole-genome sequencing in large cohorts of LBD cases and neurologically healthy controls to study the genetic architecture of this understudied form of dementia, and to generate a resource for the scientific community. Genome-wide association analysis identified five independent risk loci, whereas genome-wide gene-aggregation tests implicated mutations in the gene GBA. Genetic risk scores demonstrate that LBD shares risk profiles and pathways with Alzheimer's disease and Parkinson's disease, providing a deeper molecular understanding of the complex genetic architecture of this age-related neurodegenerative condition.

A comprehensive screening of copy number variability in dementia with Lewy bodies.

The role of genetic variability in dementia with Lewy bodies (DLB) is now indisputable; however, data regarding copy number variation (CNV) in this disease has been lacking. Here, we used whole-genome genotyping of 1454 DLB cases and 1525 controls to assess copy number variability. We used 2 algorithms to confidently detect CNVs, performed a case-control association analysis, screened for candidate CNVs previously associated with DLB-related diseases, and performed a candidate gene approach to fully explore the data. We identified 5 CNV regions with a significant genome-wide association to DLB; 2 of these were only present in cases and absent from publicly available databases: one of the regions overlapped LAPTM4B, a known lysosomal protein, whereas the other overlapped the NME1 locus and SPAG9. We also identified DLB cases presenting rare CNVs in genes previously associated with DLB or related neurodegenerative diseases, such as SNCA, APP, and MAPT. To our knowledge, this is the first study reporting genome-wide CNVs in a large DLB cohort. These results provide preliminary evidence for the contribution of CNVs in DLB risk.

Increased CSF biomarkers of angiogenesis in Parkinson disease.

OBJECTIVE: To study biomarkers of angiogenesis in Parkinson disease (PD), and how these are associated with clinical characteristics, blood-brain barrier (BBB) permeability, and cerebrovascular disease. METHODS: In this cross-sectional analysis, 38 elderly controls and 100 patients with PD (82 without dementia and 18 with dementia) were included from the prospective Swedish BioFinder study. CSF samples were analyzed for the angiogenesis biomarkers vascular endothelial growth factor (VEGF); its receptors, VEGFR-1 and VEGFR-2; placental growth factor (PlGF); angiopoietin 2 (Ang2); and interleukin-8. BBB permeability, white matter lesions (WMLs), and cerebral microbleeds (CMB) were assessed. CSF angiogenesis biomarkers were also measured in 2 validation cohorts: (1) 64 controls and 87 patients with PD with dementia; and (2) 35 controls and 93 patients with neuropathologically confirmed diagnosis of PD with and without dementia. RESULTS: Patients with PD without dementia displayed higher CSF levels of VEGF, PlGF, and sVEGFR-2, and lower levels of Ang2, compared to controls. Similar alterations in VEGF, PlGF, and Ang2 levels were observed in patients with PD with dementia. Angiogenesis markers were associated with gait difficulties and orthostatic hypotension as well as with more pronounced BBB permeability, WMLs, and CMB. Moreover, higher levels of VEGF and PlGF levels were associated with increased CSF levels of neurofilament light (a marker of neurodegeneration) and monocyte chemotactic protein-1 (a marker of glial activation). The main results were validated in the 2 additional cohorts. CONCLUSIONS: CSF biomarkers of angiogenesis are increased in PD, and they are associated with gait difficulties, BBB dysfunction, WMLs, and CMB. Abnormal angiogenesis may be important in PD pathogenesis and contribute to dopa-resistant symptoms.

Cerebrospinal fluid levels of IL-6 are decreased and correlate with cognitive status in DLB patients.

INTRODUCTION: Inflammatory processes have previously been shown to influence cognition and progression of dementia. An involvement of interleukin (IL)-6 has in particular been suggested as altered levels of IL-6 in cerebrospinal fluid (CSF) have been found in patients with Alzheimer's disease (AD). Also, an association between cognitive decline and levels of IL-6 in CSF have been reported. The aim of the present study was to investigate whether patients clinically diagnosed with dementia with Lewy bodies (DLB) display altered CSF IL-6 levels in comparison with patients with AD and control subjects without dementia and whether the IL-6 levels are correlated with cognitive status and biomarkers for AD and synucleinopathy. METHODS: To analyse CSF of patients with AD (n = 45), patients with DLB (n = 29) and control subjects without dementia (n = 36), we used immunoassays to measure levels of IL-6 (multiplex electrochemiluminescence); AD markers phosphorylated tau, total tau and amyloid-ß1-42 (enzyme-linked immunosorbent assay [ELISA]); and α-synuclein (ELISA). Cognitive status was evaluated using the Mini Mental State Examination (MMSE). RESULTS: Our analysis showed significantly lower levels of IL-6 in CSF from patients with DLB than in CSF from patients with AD and control subjects without dementia. The IL-6 levels were also negatively correlated with MMSE and positively correlated with α-synuclein CSF levels. CONCLUSIONS: Our findings support previous studies by demonstrating a link between inflammatory processes and dementia progression and further strengthen the hypothesis that IL-6 is involved in dementia pathology and cognitive decline.

Solitary living in Alzheimer's disease over 3 years: association between cognitive and functional impairment and community-based services.

INTRODUCTION: Many individuals with Alzheimer's disease (AD) live alone, and this figure is expected to increase. This study aimed to describe the cognitive and functional abilities of solitary-living AD patients, and the potential predictors of their usage of community-based services. METHODS: This 3-year, prospective, multicenter study included 1,021 participants with mild-to-moderate AD (Mini-Mental State Examination score, 10-26) treated with a cholinesterase inhibitor in a routine clinical setting. At baseline and every 6 months, patients were assessed using cognitive, instrumental, and basic activities of daily living (ADL) scales, and service utilization was recorded. Logistic regression models were used to predict the usage of community-based services. RESULTS: At the start of cholinesterase inhibitor therapy (time of AD diagnosis), 355 individuals (35%) were living alone. They were mainly female, older, had more impaired basic ADL capacity, and had a larger number of concomitant medications when compared with those living with family. Regarding the solitary-living patients, lower instrumental ADL (IADL) ability and more medications were independent predictors of usage of home-help services, whereas more impaired IADL at baseline and faster IADL deterioration were predictors of nursing home admission. For those living with family, older age, lower basic ADL, and a greater number of medications predicted home-help services, whereas a larger amount of home help predicted nursing home placement. In addition, female sex was a risk factor for both the utilization of home-help services and nursing home placement. Cognitive ability was not significantly associated with the usage of community-based services. CONCLUSION: A large number of AD patients, predominantly females, live alone with severe cognitive and functional impairment. The amount of home-help services used did not reflect cognitive severity, suggesting that home help did not meet the needs related to cognitive deterioration. Increased knowledge of how community-based services can better accommodate the care needs of solitary-living individuals with AD is essential.

Comparison of brief cognitive tests and CSF biomarkers in predicting Alzheimer's disease in mild cognitive impairment: six-year follow-up study.

INTRODUCTION: Early identification of Alzheimer's disease (AD) is needed both for clinical trials and in clinical practice. In this study, we compared brief cognitive tests and cerebrospinal fluid (CSF) biomarkers in predicting conversion from mild cognitive impairment (MCI) to AD. METHODS: At a memory clinic, 133 patients with MCI were followed until development of dementia or until they had been stable over a mean period of 5.9 years (range 3.2-8.8 years). The Mini-Mental State Examination (MMSE), the clock drawing test, total tau, tau phosphorylated at Thr(181) (P-tau) and amyloid-ß(1-42) (Aß(42)) were assessed at baseline. RESULTS: During clinical follow-up, 47% remained cognitively stable and 53% developed dementia, with an incidence of 13.8%/year. In the group that developed dementia the prevalence of AD was 73.2%, vascular dementia 14.1%, dementia with Lewy bodies (DLB) 5.6%, progressive supranuclear palsy (PSP) 4.2%, semantic dementia 1.4% and dementia due to brain tumour 1.4%. When predicting subsequent development of AD among patients with MCI, the cognitive tests classified 81% of the cases correctly (AUC, 0.85; 95% CI, 0.77-0.90) and CSF biomarkers 83% (AUC, 0.89; 95% CI, 0.82-0.94). The combination of cognitive tests and CSF (AUC, 0.93; 95% CI 0.87 to 0.96) was significantly better than the cognitive tests (p = 0.01) and the CSF biomarkers (p = 0.04) alone when predicting AD. CONCLUSIONS: The MMSE and the clock drawing test were as accurate as CSF biomarkers in predicting future development of AD in patients with MCI. Combining both instruments provided significantly greater accuracy than cognitive tests or CSF biomarkers alone in predicting AD.

Differences in survival between patients with dementia with Lewy bodies and patients with Alzheimer's disease--measured from a fixed cognitive level.

INTRODUCTION: The aim of this study was to compare survival in patients with Alzheimer's disease (AD) and patients with dementia with Lewy bodies (DLB). Since anamnestic and retrospective information about disease duration are unreliable variables, we measured survival from a fixed cognitive level. METHODS: Survival time was measured from the reported disease onset, from the time of diagnosis, from Mini-Mental State Examination (MMSE) 20 ± 1, and from MMSE 17 ± 1. RESULTS: Survival time was significantly shorter in the DLB group compared to the AD group both from the time of diagnosis and from the cognitive levels of 20 and 17 on the MMSE. There was no difference in survival when measured from the reported disease onset. DISCUSSION: Our findings indicate that DLB patients have a more malignant clinical course. Our method of investigating survival in a cognitively homogenous population may gain scientific power. Reliable methods to predict survival and the clinical course are of great value for patients, caregivers, doctors, and society.