The “Cerebrospinal Fluid Sink Therapeutic Strategy” in Alzheimer’s Disease—From Theory to Design of Applied Systems
Alzheimer’s disease (AD) is a global health problem, with incidence and prevalence considered to increase during the next decades. However, no currently available effective treatment exists despite numerous clinical trials in progress. Moreover, although many hypotheses are accepted regarding the pathophysiological mechanisms of AD onset and evolution, there are still many unknowns about the disorder. A relatively new approach, based on the amyloid-beta dynamics among different biological compartments, is currently intensely discussed, as it seems to offer a promising solution with significant therapeutic impact. Known as the “cerebrospinal-fluid-sink therapeutic strategy”, part of the “three-sink therapeutic strategy”, this theoretical model focuses on the dynamics of amyloid-beta among the three main liquid compartments of the human body, namely blood, cerebrospinal fluid, and the (brain) interstitial fluid. In this context, this article aims to describe in detail the abovementioned hypothesis, by reviewing in the first part the most relevant anatomical and physiological aspects of amyloid-beta dynamics. Subsequently, explored therapeutic strategies based on the clearance of amyloid-beta from the cerebrospinal fluid level are presented, additionally highlighting their limitations. Finally, the originality and novelty of this work rely on the research experience of the authors, who focus on implantable devices and their utility in AD treatment.
Previous studies linked disease-progression variables such as age at onset or survival to both genetic, and non-genetic factors in Parkinson's disease (PD) patients.
The aim of this study was to assess how genetic and non genetic factors act as modifiers of age at onset and survival and in a cohort of 753 PD patients, and to determine how these variables interact to define the overall risk.
We analyzed the effect of gender, tobacco, alcohol, type of PD (genetic, gPD or idiopathic, iPD) and three genetic variants rs5848- GRN, rs1042522- TP53 and APOE. We studied two cohorts (PPMI and IPDGC) to replicate positive results.
Regarding age at onset, male smokers PD had a significantly lower mean age compared to non-smoker (p = 0.001). APOE-Ɛ4 carriers had a younger onset-age compared to non-carriers (p = 0.03) in the Spanish cohort, but these results were not replicated in the other cohorts. Concerning survival, PD patients with an early onset (below 50 years) had an increased survival rate (p < 0.001).
Our study showed how several genetic and non-genetic risk factors influenced the age at onset and survival in PD.
Impact of Depression and Anxiety on Dimensions of Health-Related Quality of Life in Subjects with Parkinson’s Disease Enrolled in an Association of Patients
Here we describe the larger series of clinical cases (n = 14) with HD-like phenotype and IAs published to date. MRI and FDG-PET neuroimaging findings compatible with HD can be found in some patients with IA. Larger and more detailed series are needed to assess the pathogenic role of IAs in HTT gene.
Intermediate Alleles (IAs) are expansions of CAG repeats in the HTT gene between 27 and 35 repeats which pathogenic meaning remains controversial. They are present in the general population but there is an increasing number of cases with Huntington-like phenotype reported.
We reviewed the medical records of cases in our centre where the neurologist suspected Huntington's disease (HD) as one of the feasible diagnoses and genetic testing showed the number of CAG repeats was in the “intermediate range”. We gathered the type of symptoms in all cases and the main neuroimaging findings when available.
We found 14 cases, 8 males and 6 females, with average age at onset at 64 years old. Most cases exhibited some type of extrapyramidal symptoms. Cognitive and/or behavioral symptoms were also present in most cases (being depression, anxiety and cognitive impairment the most frequent ones). In one case we found deposits of iron in the basal ganglia in the MRI, and in another case we found diffuse cortical hypometabolism with predominantly frontal bilateral involvement and bilateral focal deficit of both caudate and thalamus in the FDG-PET.
The clinical and neuroimaging findings of some cases with IA in this series are compatible with the clinical picture of HD but also with several other alternative diagnoses. Therefore we can not establish association between IA and HD. Larger series with more comprehensive diagnostic workout and neuropathological studies are needed to confirm or rule out whether IAs in the HTT gene may cause HD.
Patients with Parkinson’s Disease Show Alteration in their Visuospatial Abilities and in their Egocentric and Allocentric Spatial Orientation Measured by Card Placing Tests
A role for ATXN1, ATXN2 and HTT intermediate repeats in frontotemporal dementia and Alzheimer's disease
The Genetic Architecture of Parkinson Disease in Spain: Characterizing Population‐Specific Risk, Differential Haplotype Structures, and Providing Etiologic Insight
Reference: Front. Neurol., 18 October 2019 | https://doi.org/10.3389/fneur.2019.01036
Prevalence of Depression and Anxiety in Parkinson Disease and Impact on Quality of Life: A Community-Based Study in Spain
Full text https://doi.org/10.1177/0891988719874130
Perrault syndrome with neurological features in a compound heterozygote for two TWNK mutations: overlap of TWNK-related recessive disorders
Reference: Journal of Translational Medicine volume 17, Article number: 290 (2019) Full text