The Vallecas Project: A Cohort to Identify Early Markers and Mechanisms of Alzheimer’s Disease

Abstract

IntroductionAlzheimer’s disease (AD) is a major threat for the well-being of an increasingly aged world population. The physiopathological mechanisms of late-onset AD are multiple, possibly heterogeneous, and not well understood. Different combinations of variables from several domains (i.e., clinical, neuropsychological, structural, and biochemical markers) may predict dementia conversion, according to distinct physiopathological pathways, in different groups of subjects.MethodsWe launched the Vallecas Project (VP), a cohort study of non-demented people aged 70–85, to characterize the social, clinical, neuropsychological, structural, and biochemical underpinnings of AD inception. Given the exploratory nature of the VP, multidimensional and machine learning techniques will be applied, in addition to the traditional multivariate statistical methods.ResultsA total of 1169 subjects were recruited between October 2011 and December 2013. Mean age was 74.4 years (SD 3.9), 63.5% of the subjects were women, and 17.9% of the subjects were carriers of at least one ε4 allele of the apolipoprotein E gene. Cognitive diagnoses at inclusion were as follows: normal cognition 93.0% and mild cognitive impairment (MCI) 7.0% (3.1% amnestic MCI, 0.1% non-amnestic MCI, 3.8% mixed MCI). Blood samples were obtained and stored for future determinations in 99.9% of the subjects and 3T magnetic resonance imaging study was conducted in 89.9% of the volunteers. The cohort is being followed up annually for 4 years after the baseline.ConclusionWe have established a valuable homogeneous single-center cohort which, by identifying groups of variables associated with high risk of MCI or dementia conversion, should help to clarify the early physiopathological mechanisms of AD and should provide avenues for prompt diagnosis and AD prevention.

Diagnostic criteria and prevalence of mild cognitive impairment in older adults living in the community: a systematic review and meta-analysis

“…In the end, the study may be classified as low risk (score 0-3), moderate risk (4-6), or high risk (7)(8)(9). Of the 35 articles selected, five presented a moderate risk of bias [9][10][11][12][13] . All other articles scored between 0 and 3 (low risk).…”

Predicting the future development of mild cognitive impairment in the cognitively healthy elderly

“…Subjects involved in this study were volunteers participating in the 'Alzheimer's disease Vallecas Project', a single-centre longitudinal community-based study 30 For the purpose of the current study, we applied further specific exclusion criteria. In our first analyses, conducted in 2015-2016, we identified individuals who converted from cognitively healthy to MCI from baseline visit (V1) to V2 (Figure 1)…”

“…In the following visits in subsequent years (V2 onwards) the same procedure was repeated, excluding genetic testing. assessments is described elsewhere 30,59 .…”

“…We applied these techniques to data from the Vallecas Project 30 , a single-site, community-based, longitudinal study on a recruited pool of 1,213 individuals aged 69-86 and followed up at yearly intervals. At each visit, volunteers undergo detailed neuropsychological and clinical evaluation, and 3 Tesla (3T) MRI, to assess noninvasively the macroscopic consequence of neuronal damage occurring in neurodegeneration.…”

Elevated Plasma microRNA-206 Levels Predict Cognitive Decline and Progression to Dementia from Mild Cognitive Impairment

“…Blood samples were collected with citrate and centrifuged at 2280 g for 10 min followed by 10 min at 13,000 rpm within 1 h of collection. Platelet-free plasma was then stored at −80 • C. All blood samples (Control, MCI, and AD) were collected at the same Center (CIEN Foundation, Madrid, Spain), by the same group of technicians and using the same protocol [21], thus assuring that sample processing is comparable. All samples are stored under the same conditions following identical protocols.…”