Diagnostic criteria in dementing illness. What's new?

The spectrum of neurodegenerative diseases that primarily affect cognition and behaviorspreads from asymptomatic preclinical disease to very mild cognitive impairment to frank dementia. Alzheimer's disease (AD) is the most common cause of a decline in cognitive ability. Also, it is a devastating condition that affects patients and their entirefamilies of caregivers, exacting tremendous financial hardships. Diagnosis may be complicated by other forms of dementia that have symptoms and pathologies similar to AD. Knowing the key features and pathology of each type of dementia can help in the accurate diagnosis of patients, so they will receive the treatment and support services appropriate for their condition and maintain the highest possible functioning in daily life and quality of life. Differentiate, based on clinical criteria, neuropathology, and biomarkers, AD and its atypical variants from other common dementias including Dementia with Lewy Bodies, Vascular Cognitive Impairment, Frontotemporal Degeneration, and less frequent cognitive disorders. The importance of getting an accurate and early diagnosis of dementiais now increasingly significant to make important decisions about treatment, support, and care. Nonpharmacological as well as pharmacological interventions should be initiated once the diagnosis is obtained. Biochemical markers to identify Alzheimer's disease play a central role in the new diagnostic criteria for the disease and in the recent biological definition of AD. This review article presents up-to-date data regarding the recent diagnostic criteria of Alzheimer´s disease and related disorders, emphasizing its usefulness in routine clinical practice.

Time-restricted feeding modulates the DNA methylation landscape, attenuates hallmark neuropathology and cognitive impairment in a mouse model of vascular dementia

Objective: Vascular dementia (VaD) is the second most common cause of dementia worldwide. The increasing contribution of lifestyle-associated risk factors to VaD has pointed towards gene-environment interactions (i.e. epigenetics). This study thus aims to investigate the DNA methylation landscape in a chronic cerebral hypoperfusion (CCH) mouse model of VaD. As a nexus between the gene-environment interaction, intermittent fasting (IF) was introduced as a prophylactic intervention.

Methods: Bilateral common carotid artery stenosis (BCAS) was used to induce CCH by placing micro-coils of 0.18 mm in each common carotid artery of the mice. The coils were left in the mice for 7, 15 and 30 days to study temporal differences. IF was introduced for 16 h daily for 4 months prior to BCAS. Reduced Representation Bisulfite Sequencing (RRBS) was used to study the DNA methylation landscape. Cognitive impairment was measured using Barnes Maze Test. White matter lesions (WML) and neuronal loss were measured using Luxol fast blue staining and cresyl violet staining respectively.

Results: IF mice subjected to CCH displayed significantly better cognitive learning ability and memory, improved neuropathological alterations with reduced WMLs and neuronal loss. Modulation of DNA methylation patterns in the cortex of AL CCH mice was re-modelled and signs of reversal was observed in IF CCH mice across all three timepoints.

Conclusions: These findings provide an understanding of how IF may protect the brain against damage caused by CCH and show promise in offering potential beneficial effects in mitigating the neuropathology and cognitive deficits in VaD.

Vascular contributions to cognitive impairment and dementia: the emerging role of 20-HETE

The accumulation of extracellular amyloid-β (Aβ) and intracellular hyperphosphorylated τ proteins in the brain are the hallmarks of Alzheimer's disease (AD). Much of the research into the pathogenesis of AD has focused on the amyloid or τ hypothesis. These hypotheses propose that Aβ or τ aggregation is the inciting event in AD that leads to downstream neurodegeneration, inflammation, brain atrophy and cognitive impairment. Multiple drugs have been developed and are effective in preventing the accumulation and/or clearing of Aβ or τ proteins. However, clinical trials examining these therapeutic agents have failed to show efficacy in preventing or slowing the progression of the disease. Thus, there is a need for fresh perspectives and the evaluation of alternative therapeutic targets in this field. Epidemiology studies have revealed significant overlap between cardiovascular and cerebrovascular risk factors such as hypertension, diabetes, atherosclerosis and stroke to the development of cognitive impairment. This strong correlation has given birth to a renewed focus on vascular contributions to AD and related dementias. However, few genes and mechanisms have been identified. 20-Hydroxyeicosatetraenoic acid (20-HETE) is a potent vasoconstrictor that plays a complex role in hypertension, autoregulation of cerebral blood flow and blood-brain barrier (BBB) integrity. Multiple human genome-wide association studies have linked mutations in the cytochrome P450 (CYP) 4A (CYP4A) genes that produce 20-HETE to hypertension and stroke. Most recently, genetic variants in the enzymes that produce 20-HETE have also been linked to AD in human population studies. This review examines the emerging role of 20-HETE in AD and related dementias.

A Multicenter, Randomized, Double-blind, Placebo-controlled Clinical Trial for Efficacy of Acetyl-L-carnitine in Patients with Dementia Associated with Cerebrovascular Disease

Background and Purpose

Acetyl-L-carnitine (ALC) is a widely used drug for various neurodegenerative diseases including dementia. The aim of the present study was to elucidate the efficacy of ALC in dementia patients with cerebrovascular disease (vascular cognitive impairment; VCI).

Methods

Fifty-six patients were randomized to treatment with 500 mg ter in die ALC, or placebo in this 28-week, double-blind, placebo-controlled trial. The primary outcome measure was the Korean version of Montreal Cognitive Assessment (MoCA-K).

Results

Following treatment with ALC, the cognitive function measured by the MoCA-K was significantly improved in the ALC-treated groups. However, other secondary outcomes were not statistically significant between ALC- and placebo-treated groups. In MoCA-K analysis, attention and language sub-items significantly favored the ALC-treated group.

Conclusions

Compared with placebo, treatment with ALC 1,500 mg/day produced significant changes in MoCA-K in dementia patients with VCI. ALC was well tolerated in this population. Despite the study limitations, the findings suggested the potential benefits associated with the use of ALC in dementia patients with VCI.

Neuropsychiatric symptoms in Vascular Cognitive Impairment: a systematic review

Neuropsychiatric symptoms or Behavioral and Psychological Symptoms of Dementia (BPSD) are common and invariably appear at some point during the course of the disease, mediated both by cerebrovascular disease and neurodegenerative processes. Few studies have compared the profiles of BPSD in Vascular Cognitive Impairment (VCI) of different subtypes (subcortical or cortical) and clinical stages (Vascular Cognitive Impairment No Dementia [VaCIND] and Vascular Dementia [VaD]).

Alzheimer and vascular brain diseases: Focal and diffuse subforms

Alois Alzheimer is best known for his description of the pre-senile neurodegenerative disease named after him. However, his previous interest in vascular brain diseases, underlying cognitive and behavioral changes, was very strong. Besides describing the Arteriosclerotic atrophy of the brain and the arteriosclerotic subtype of Senile dementia which he viewed as main forms of vascular brain diseases, he also identified and described a series of conditions he considered subforms. These may be divided, as suggested by the authors of the present paper, into 3 groups: gliosis and sclerosis, subcortical atrophies, and apoplectic. The subforms of the three groups present characteristic neuropathological features and clinical, cognitive and behavioral manifestations. These provide the basis, together with part of the main forms, for the contemporary condition known as Vascular Cognitive Impairment.