Altered retinal cerebral vessel oscillation frequencies in Alzheimer's disease compatible with impaired amyloid clearance.

Retinal vessels are similar to cerebral vessels in their structure and function. Moderately low oscillation frequencies of around 0.1 Hz have been reported as the driving force for paravascular drainage in gray matter in mice and are known as the frequencies of lymphatic vessels in humans. We aimed to elucidate whether retinal vessel oscillations are altered in Alzheimer's disease (AD) at the stage of dementia or mild cognitive impairment (MCI). Seventeen patients with mild-to-moderate dementia due to AD (ADD); 23 patients with MCI due to AD, and 18 cognitively healthy controls (HC) were examined using Dynamic Retinal Vessel Analyzer. Oscillatory temporal changes of retinal vessel diameters were evaluated using mathematical signal analysis. Especially at moderately low frequencies around 0.1 Hz, arterial oscillations in ADD and MCI significantly prevailed over HC oscillations and correlated with disease severity. The pronounced retinal arterial vasomotion at moderately low frequencies in the ADD and MCI groups would be compatible with the view of a compensatory upregulation of paravascular drainage in AD and strengthen the amyloid clearance hypothesis.

Development and testing of an informative guide about palliative care for family caregivers of people with advanced dementia.

BACKGROUND: Since people with advanced dementia are usually not able to make complex decisions, it is usually the family caregivers, as proxies, who have to decide on treatments and their termination. However, these decisions are difficult for the caregivers to make, as they are often inadequately informed and cannot properly assess the consequences; moreover, they are concerned about harming the sick person. We aimed to first develop an informative booklet about palliative care issues for caregivers of people with advanced dementia. Secondly, we aimed to investigate a change in family caregivers' knowledge regarding palliative care issues and caregivers' involvement in medical and care decisions before and after studying this booklet. METHODS: A first version of the booklet was drafted by an experienced psychiatrist and palliative care specialist based on existing booklets and guidelines; necessary cultural adaptions were taken into consideration. A nominal group process was conducted to develop the informative guide. In order to investigate the acceptance of the booklet and the possibility to implement it, 38 patient-caregiver dyads were recruited, and caregivers were interviewed both before receiving the booklet and after 3 months of receiving the booklet. RESULTS: Experts from various disciplines collaborated on a German booklet for family caregivers of people with advanced dementia as an information aid regarding issues of palliative care. The subsequent test showed that all caregivers had experienced a personal benefit from the booklet. Caregivers had a significant gain of knowledge after provision of the booklet. A large proportion of caregivers who had not previously considered and/or discussed medical topics reported that they had done so within 3 months after obtaining the booklet, or planned to do so in the near future. CONCLUSIONS: The caregivers valued the comprehensible, concise and well-structured information guide on palliative care issues in advanced dementia. They agreed it increases knowledge and prompts decision making and therefore should be developed in many languages and disseminated among family caregivers of people with dementia. TRIAL REGISTRATION: clinicaltrial.gov, NCT03548142. Retrospectively registered 7 June 2018.

Associations of Neprilysin Activity in CSF with Biomarkers for Alzheimer's Disease.

BACKGROUND: Neprilysin (NEP) cleaves amyloid-ß 1-42 (Aß42) in the brain. Hence, we aimed to elucidate the effect of NEP on Aß42 in cerebrospinal fluid (CSF) and on in vivo brain amyloid load using amyloid positron emission tomography (PET) with [11C]PiB (Pittsburgh compound B). In addition, associations with the biomarkers for neuronal injury, CSF-tau and FDG-PET, were investigated. METHODS: Associations were calculated using global and voxel-based (SPM8) linear regression analyses in the same cohort of 23 highly characterized Alzheimer's disease patients. RESULTS: CSF-NEP was significantly inversely associated with CSF-Aß42 and positively with the extent of neuronal injury as measured by CSF-tau and FDG-PET. CONCLUSIONS: Our results on CSF-NEP are compatible with the assumption that local degradation, amongst other mechanisms of amyloid clearance, plays a role in the development of Alzheimer's pathology. In addition, CSF-NEP is associated with the extent and the rate of neurodegeneration.