Current Alzheimer Research - Volume 14, Issue 5, 2017

Background: Advancing age is associated with high prevalence of pain, sleep problems and dementia. Dementia is frequently accompanied by distressing behavioral and psychological symptoms, including sleep problems. The etiology of sleep problems in dementia is multifactorial. It has been suggested that untreated pain may contribute to sleep problems, and pain treatment has been shown to reduce sleep problems in people with dementia. Objective: This systematic review aims to provide an overview of the studies that have investigated the association and/or possible interaction between pain and sleep in dementia. Methods: A systematic search was performed in MEDLINE, EMBASE, Cochrane and PsychINFO, including text words and MESH terms covering dementia, pain and sleep. Also, reference lists in the included publications were examined to retrieve publications. Publications had to investigate sleep and pain in relation to dementia to be included in this review. Results: The search produced 1750 independent hits. Out of the 49 publications studied in full text, 11 publications were included. Only one controlled trial was identified and represented the only insights to the possible interactional relationship between pain, sleep and dementia. Pain or pain intensity were related to sleep in 6 of the included studies, while the remaining studies could neither support nor contradict a relationship between sleep and pain in people with dementia. None of the studies employed objective sleep assessment. Conclusion: There is a need for high quality studies investigating the interaction between sleep and pain in people with dementia, using objective sleep measurements and pain assessment suitable for people with dementia.

The p75 neurotrophin receptor (p75NTR) is a single membrane-spanning receptor in the tumor necrosis factor (TNF) death domain containing receptor family. p75NTR has multiple faces of biological or pathogenic functions by partnering with the three major neurotrophin receptors, including tropomyosin receptor kinase (Trk), sortilin and Nogo receptors. By partnering with different co-receptors, p75NTR regulates the binding of mature or pro-neurotrophins and activation of different signaling pathways, resulting in outcomes ranging from growth and survival to cell death or apoptosis. In this review, we summarized the role of p75NTR in maintaining the hemostasis of the brain, and briefly introduced its participation in the pathogenesis of several neurodegenerative diseases. The complexity of p75NTR enables it to be a potent therapeutic target of many diseases by modulating functions of the receptor.