Abstract
Background/Objectives: Mild cognitive impairment (MCI) has been associated with risk for Alzheimer's Disease (AD). Previous investigations have suggested that vascular risk factors (VRFs) were associated with cognitive decline and AD pathogenesis, and the intervention of VRFs may be a possible way to prevent dementia. However, in MCI, little is known about the potential impacts of VRFs on neural networks and their neural substrates, which may be a neuroimaging biomarker of the disease progression.Methods: 128 elderly Han Chinese participants (67 MCI subjects and 61 matched normal elderly) with or without VRFs (hypertension, diabetes mellitus, hypercholesterolemia, smoking and alcohol drinking) underwent the resting-state functional magnetic resonance imaging (fMRI) and neuropsychological tests. We obtained the default mode network (DMN) to identify alterations in MCI with the varying number of the VRF and analyzed the significant correlation with behavioral performance.Results: The effects of VRF on the DMN were primarily in bilateral dorsolateral prefrontal cortex (DLPFC) (i.e., middle frontal gyrus). Normal elderly showed the gradually increased functional activity of DLPFC, while a fluctuant activation of DLPFC was displayed in MCI with the growing number of the VRF. Interestingly, the left DLPFC further displayed significantly dynamic correlation with executive function as the variation of VRF loading. Initial level of compensation was observed in normal aging and none-vascular risk factor (NVRF) MCI, while these compensatory neural processes were suppressed in One-VRF MCI and were subsequently re-aroused in Over-One-VRF MCI.Conclusions: These findings suggested that the dose-dependent effects of VRF on DLPFC were highlighted in MCI, and the dynamic compensatory neural processes that fluctuated along with variations of VRF loading could be key role in the progression of MCI.
Highlights
Alzheimer’s Disease (AD) is the most common neurodegenerative disorder in elderly people worldwide
The mild cognitive impairment (MCI) subjects included in the study were diagnosed based on the recommendations of Petersen et al and National Institute on Aging-Alzheimer’s Association (NIA-AA)(Petersen, 2004; Albert et al, 2011): (i) subjective memory impairment corroborated by the subject and/or an informant; (ii) objective memory performance documented by an auditory verbal learning test-delayed recall (AVLT-DR) score less than or equal to 1.5 standard deviation (SD) of age-adjusted and education-adjusted norms; (iii) mini mental state examination (MMSE) score ≥ 24; (iv) clinical dementia rating (CDR) of 0.5; (v) no or minimal impairment in activities of daily living; and (vi) absence of dementia or insufficient dementia to meet the criteria of NIA-AA for AD
In consideration of the main effect of disease, MCI subjects displayed significantly poor performances on general cognition, episodic memory (EM), visuospatial function (VF), information processing speed and executive function compared with healthy control (HC) subjects
Summary
Alzheimer’s Disease (AD) is the most common neurodegenerative disorder in elderly people worldwide It encompasses the progressive continuum of impairment from mild cognitive impairment (MCI) whose potential pathophysiology is related to AD to dementia (Albert et al, 2011). VRFs-related endothelial dysfunction, in turn leading to chronic cerebral hypoperfusion, may be a key pathophysiological mechanism of VCID (Duncombe et al, 2017). These VRFs have been known as modifiable risk factors currently. There has been abundant and compelling evidence showing its feasibility (Love and Miners, 2016; Maliszewska-Cyna et al, 2017)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
