A neurodegenerative vascular burden index and the impact on cognition

Vascular Risk Factors and Cognition in Multiple System Atrophy

Objective: Vascular risk factors have been reported to be associated with cognitive impairment (CI) in the general population, but their role on CI in multiple system atrophy (MSA) is unclear. This study aimed to explore the relationship between vascular risk factors and CI in patients with MSA. Methods: The clinical data and vascular risk factors were collected. The Montreal Cognitive Assessment tool was used to test the cognitive function of patients with MSA. Binary logistic regression was used to analyze the correlation between vascular risk factors and CI. Results: A total of 658 patients with MSA with a mean disease duration of 2.55 ± 1.47 years were enrolled. In MSA patients, hypertension was recorded in 20.2%, diabetes mellitus in 10.3%, hyperlipidemia in 10.2%, smoking in 41.2%, drinking in 34.8%, and obesity in 9.6%. The prevalence of CI in patients with MSA, MSA with predominant parkinsonism (MSA-P), and MSA with predominant cerebellar ataxia (MSA-C) was 45.0, 45.1, and 44.9%, respectively. In the binary logistic regression model, patients with more than one vascular risk factors were significantly more likely to have CI in MSA (OR = 4.298, 95% CI 1.456-12.691, P = 0.008) and MSA-P (OR = 6.952, 95% CI 1.390-34.774, P = 0.018), after adjusting for age, sex, educational years, disease duration, and total Unified multiple system atrophy rating scale scores. Conclusion: Multiple vascular risk factors had a cumulative impact on CI in MSA. Therefore, the comprehensive management of vascular risk factors in MSA should not be neglected.

Blood-Brain Barrier Crossing Renin-Angiotensin Drugs and Cognition in the Elderly: A Meta-Analysis

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Hair cortisol in patients with a depressive episode treated with electroconvulsive therapy

BACKGROUND

There is substantial evidence showing changes in hypothalamic pituitary adrenal (HPA)-axis activity in patients with major depressive disorder (MDD). Also, there seem to be differences in HPA-axis functioning between MDD subgroups. It is however unclear whether hair cortisol concentrations (HCC), which are a stable marker of long-term cortisol levels, are suitable as a biomarker for identifying subgroups in MDD.

METHODS

We were able to attain valid HCC from a scalp hair sample of sixty-two patients with a major depressive episode right before electroconvulsive therapy (ECT). HCC were our main biological outcome measure. We created subgroups using depression severity as defined by the Hamilton Depression Rating Scale, the presence/absence of psychotic symptoms, the presence of melancholia as defined by the CORE and catatonia as defined by the Bush-Francis Catatonia Rating Scale.

RESULTS

Our analyses of the total group showed a median HCC of 4.4 pg/mg. We found patients with catatonia (N = 10) to have substantially higher median HCC (8.3 pg/mg) than patients without catatonia (3.8 pg/mg). Although presence of melancholia and depression severity were not significantly associated with HCC, more severe psychomotor agitation was associated with higher HCC. Pre-treatment HCC was not associated with ECT outcome.

STRENGTHS AND LIMITATIONS

A complicating factor in interpretation of our results was the large variability in HCC. This could be related to potential confounders such as cardiometabolic and other comorbidities, that were however addressed to the extent possible.

CONCLUSIONS

HCC is a potential biomarker for MDD patients with severe agitation and/or catatonia. CLINICALTRIALS.GOV: Identifier: NCT02562846.

Cerebral Perfusion Enhancing Interventions: A New Strategy for the Prevention of Alzheimer Dementia

Cardiovascular and cerebrovascular diseases are major risk factors in the development of cognitive impairment and Alzheimer's disease (AD). These cardio-cerebral disorders promote a variety of vascular risk factors which in the presence of advancing age are prone to markedly reduce cerebral perfusion and create a neuronal energy crisis. Long-term hypoperfusion of the brain evolves mainly from cardiac structural pathology and brain vascular insufficiency. Brain hypoperfusion in the elderly is strongly associated with the development of mild cognitive impairment (MCI) and both conditions are presumed to be precursors of Alzheimer dementia. A therapeutic target to prevent or treat MCI and consequently reduce the incidence of AD aims to elevate cerebral perfusion using novel pharmacological agents. As reviewed here, the experimental pharmaca include the use of Rho kinase inhibitors, neurometabolic energy boosters, sirtuins and vascular growth factors. In addition, a compelling new technique in laser medicine called photobiomodulation is reviewed. Photobiomodulation is based on the use of low level laser therapy to stimulate mitochondrial energy production non-invasively in nerve cells. The use of novel pharmaca and photobiomodulation may become important tools in the treatment or prevention of cognitive decline that can lead to dementia.

Carotid atherosclerosis promotes the progression of Alzheimer's disease: A three-year prospective study

Although cerebrovascular diseases have been considered as risk factors for cognitive decline and dementia, the associations between atherosclerosis and Alzheimer's disease (AD) have not been fully examined and remain controversial. The aim of this three-year prospective study was to investigate whether arotid artery atherosclerosis accelerates cognitive impairment in AD patients. The association of carotid intimal medial thickness (IMT) with prospective trajectories of cognitive function was assessed among 521 patients with light to moderate AD, and 437 AD patients were followed up annually for 3 years. Participants underwent initial carotid ultrasonography and repeated neuropsychological testing every year. Mixed-effects regression analyses were adjusted to estimate the effect of carotid IMT and other adjusting variables. The results of the present study indicated that carotid IMT was significantly associated with various measures of cognitive function. Furthermore, AD patients with higher carotid IMT values had a faster decline in cognitive scores in a variety of neuropsychological tests, particularly in verbal and non-verbal memory, semantic fluency and executive function. The present prospective study showed that carotid atherosclerosis is a predictive factor regarding the progression of cognitive impairment in AD patients, suggesting that early detection and treatment of vascular risk factors may prevent or at least postpone the evolution of the disease.

Vascular Risk Factors and Cognition in Parkinson's Disease

Vascular risk factors have been associated with cognitive deficits and incident dementia in the general population, but their role on cognitive dysfunction in Parkinson's disease (PD) is still unclear. The present study addresses the single and cumulative effect of vascular risk factors on cognition in PD patients, taking clinical confounders into account. Standardized neuropsychological assessment was performed in 238 consecutive PD patients. We evaluated the association of single and cumulative vascular risk factors (smoking, diabetes, hypercholesterolemia, hypertension, and heart disease), with the diagnosis of PD normal cognition (PDNC, n = 94), mild cognitive impairment (PD-MCI, n = 111), and dementia (PDD, n = 33). The association between single neuropsychological tests and vascular risk factors was evaluated with covariance analyses adjusted for age at onset, educational levels, gender, disease duration, and motor performance. Age, educational levels, disease duration, and motor function were significantly different between PDNC, PD-MCI, and PDD. Heart disease was the only vascular factor significantly more prevalent in PDD compared with PDNC in adjusted analyses. Performance of tests assessing executive and attention functions were significantly worse in patients with hypertension, heart disease, and/or diabetes (p <  0.05). Heart disease is associated with dementia in PD, suggesting a potential window of intervention. Vascular risk factors act especially on attention and executive functions in PD. Vascular risk stratification may be useful in order to identify PD patients with a greater risk of developing dementia. These findings need to be verified in longitudinal studies.

Brain activation in frontotemporal and Alzheimer's dementia: a functional near-infrared spectroscopy study

Background

Frontotemporal dementia is an increasingly studied disease, the underlying functional impairments on a neurobiological level of which have not been fully understood. Patients with the behavioral-subtype frontotemporal dementia (bvFTD) are particularly challenging for clinical measurements such as functional imaging due to their behavioral symptoms. Here, an alternative imaging method, functional near-infrared spectroscopy (fNIRS), is introduced to measure task-related cortical brain activation based on blood oxygenation. The current study investigated differences in cortical activation patterns of patients with bvFTD, Alzheimer’s dementia (AD), and healthy elderly subjects measured by fNIRS.

Method

Eight probable bvFTD patients completed the semantic, phonological, and control conditions of a verbal fluency task. Eight AD patients and eight healthy controls were compared on the same task. Simultaneously, an fNIRS measurement was conducted and analyzed using a correction method based on the expected negative correlation between oxygenated and deoxygenated hemoglobin.

Results

Healthy controls show an increase in cortical activation measured in frontoparietal areas such as the dorsolateral prefrontal cortex. The activation pattern of patients with AD is similar, but weaker. In contrast, bvFTD patients show a more frontopolar pattern, with activation of Broca’s area, instead of the dorsolateral prefrontal cortex and the superior temporal gyrus. The frontoparietal compensation mechanisms, seen in the healthy elderly, were missing in bvFTD patients.

Conclusion

Different frontoparietal cortical activation patterns may indicate a correlate of diverse pathophysiological mechanisms of AD and bvFTD during verbal fluency processing. The AD pattern is weaker and more similar to the healthy pattern, whereas the bvFTD pattern is qualitatively different, namely more frontopolar and without frontoparietal compensation activation. It adheres to a change of cortical activation during the course of the disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13195-016-0224-8) contains supplementary material, which is available to authorized users.

Pharmacologically-induced neurovascular uncoupling is associated with cognitive impairment in mice

There is increasing evidence that vascular risk factors, including aging, hypertension, diabetes mellitus, and obesity, promote cognitive impairment; however, the underlying mechanisms remain obscure. Cerebral blood flow (CBF) is adjusted to neuronal activity via neurovascular coupling (NVC) and this mechanism is known to be impaired in the aforementioned pathophysiologic conditions. To establish a direct relationship between impaired NVC and cognitive decline, we induced neurovascular uncoupling pharmacologically in mice by inhibiting the synthesis of vasodilator mediators involved in NVC. Treatment of mice with the epoxygenase inhibitor N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MSPPOH), the NO synthase inhibitor l-NG-Nitroarginine methyl ester (L-NAME), and the COX inhibitor indomethacin decreased NVC by over 60% mimicking the aging phenotype, which was associated with significantly impaired spatial working memory (Y-maze), recognition memory (Novel object recognition), and impairment in motor coordination (Rotarod). Blood pressure (tail cuff) and basal cerebral perfusion (arterial spin labeling perfusion MRI) were unaffected. Thus, selective experimental disruption of NVC is associated with significant impairment of cognitive and sensorimotor function, recapitulating neurologic symptoms and signs observed in brain aging and pathophysiologic conditions associated with accelerated cerebromicrovascular aging.

Urinary kallidinogenase for the treatment of cerebral arterial stenosis

Aim

Urinary kallidinogenase (UK) has shown promise in improving cerebral perfusion. This study aimed to examine how UK affects cognitive status and serum levels of amyloid betas (Aβs) 1-40 and 1-42 in patients with cerebral arterial stenosis.

Methods

Ninety patients with cerebral arterial stenosis were enrolled, of whom 45 patients received UK + conventional treatment (UK group), and 45 patients received conventional treatment alone as control group. Cognitive status and Aβ1-40 and Aβ1-42 serum levels were determined before treatment and at 4 weeks and 8 weeks after treatment.

Results

At 4 weeks after treatment, cognitive status in patients treated with UK clearly improved accompanied by Aβ1-40 serum levels decreasing while there was no change of Aβ1-42. Cognitive status in patients receiving UK continued to improve, Aβ1-40 serum levels declined further as well as Aβ1-42 serum levels began to decrease dramatically at 8 weeks after treatment.

Conclusion

UK could improve cognitive status and decrease both Aβ1-40 and Aβ1-42 serum levels to prevent ischemic cerebral injury, which represents a good option for patients with cerebral arterial stenosis.

Age and Vascular Burden Determinants of Cortical Hemodynamics Underlying Verbal Fluency

BACKGROUND

Aging processes and several vascular burden factors have been shown to increase the risk of dementia including Alzheimer's disease. While pathological alterations in dementia precede diagnosis by many years, reorganization of brain processing might temporarily delay cognitive decline. We hypothesized that in healthy elderly individuals both age-related neural and vascular factors known to be related to the development of dementia impact functional cortical hemodynamics during increased cognitive demands.

METHODS

Vascular burden factors and cortical functional hemodynamics during verbal fluency were assessed in 1052 non-demented elderly individuals (51 to 83 years; cross-sectional data of the longitudinal TREND study) using functional near-infrared spectroscopy (fNIRS). The prediction of functional hemodynamic responses by age in multiple regressions and the impact of single and cumulative vascular burden factors including hypertension, diabetes, obesity, smoking and atherosclerosis were investigated.

RESULTS

Replicating and extending previous findings we could show that increasing age predicted functional hemodynamics to be increased in right prefrontal and bilateral parietal cortex, and decreased in bilateral inferior frontal junction during phonological fluency. Cumulative vascular burden factors, with hypertension in particular, decreased left inferior frontal junction hemodynamic responses during phonological fluency. However, age and vascular burden factors showed no statistical interaction on functional hemodynamics.

CONCLUSION

Based on these findings, one might hypothesize that increased fronto-parietal processing may represent age-related compensatory reorganization during increased cognitive demands. Vascular burden factors, such as hypertension, may contribute to regional cerebral hypoperfusion. These neural and vascular hemodynamic determinants should be investigated longitudinally and combined with other markers to advance the prediction of future cognitive decline and dementia.

Subclinical atherosclerosis and increased risk of hearing impairment

OBJECTIVE

The study's purpose was to test if subclinical atherosclerosis was associated with the risk of developing HI in a large cohort of middle-aged participants.

METHODS

Study subjects were members of the Beaver Dam Offspring Study (BOSS), a longitudinal study of adult children of participants in the population-based Epidemiology of Hearing Loss Study (1993-present). BOSS examinations took place in 2005-2008 (baseline) and 2010-2013 (5-year follow-up). The 5-year incidence of hearing impairment was defined as a pure-tone average (PTA) of thresholds at 0.5, 1, 2 and 4 kHz > 25 dB Hearing Level (dB HL) in either ear at follow-up among participants at risk (baseline PTA in both ears < = 25 dB HL; n = 2436, mean age = 47.7 years). Atherosclerosis was measured as the mean carotid intima-media thickness and the presence of carotid artery plaque.

RESULTS

Among the 1984 participants at-risk with a follow-up audiometric examination, the 5-year incidence of hearing impairment was 8.3% (95% Confidence Interval (C.I.) 7.1, 9.5). With multivariable adjustment, carotid intima-media thickness was positively associated with hearing impairment incidence (Relative Risk (RR) = 1.14 per 0.1 mm, 95% C.I. 1.04, 1.24). The number of sites (0-6) with plaque was also positively associated with the incidence of impairment (RR = 1.16 per site, 95% C.I. 1.01, 1.32).

CONCLUSION

Atherosclerosis was associated with the 5-year incidence of hearing impairment in this predominantly middle-aged cohort. Interventions targeting atherosclerosis prevention may help to prevent or delay the onset of hearing impairment.