Apolipoprotein E epsilon4 allele is associated with left ventricular systolic dysfunction

P2X7 Receptor and APOE Polymorphisms and Survival from Heart Failure: A Prospective Study in Frail Patients in a Geriatric Unit

Heart failure (HF) is one of the most frequent cause of hospitalization in elderly and often coexists with concurrent geriatric syndromes, like cognitive disturbances; various pathophysiological mechanisms are shared by HF and cognitive decline, notably a substrate of low-grade inflammation. We investigated whether SNPs in the purinergic receptor (P2X7R) and apolipoprotein (APO) E genes, both involved in a series of inflammatory responses, are associated to HF or cognitive impairment and are able to predict post-discharge mortality in the elderly. We prospectively analyzed 198 patients (age 85 ± 8 years, predominantly females) admitted to a Geriatric unit for acute HF, whose diagnosis was based on clinical signs, brain natriuretic peptide (BNP) values and ecocardiography in uncertain diagnosis (BNP values between 100 and 400 pg/mL); cognitive performance was assesed by Short Portable Mental Status Questionnaire (SPMSQ). In all the participants, SNPs rs208294 and rs3751143 for P2X7R gene and rs429558 and rs7412 for APOE gene were assessed. Information on all-cause mortality was adjudicated by medical records review 36 months after discharge. We found no relationship between P2X7R and APOE polymorphisms and 36-month post-discharge mortality; a better outcome for overall survival was observed in patients with BNP values below the median (281 pg/mL) (p=0.002) persisting after adjustment for renal function and age, and in those with cognitive impairment (p<0.001). Patients harboring APOE-ε4 genotype showed higher BNP concentrations than noncarriers (1289.9 ± 226.9 vs 580.5 ± 90.2 pg/mL respectively,p=0.004), whereas none of the studied SNPs were associated to impairment in cognitive performance. In conclusion, neither P2X7R or APOE genotype seem to predict long-term mortality in elderly patients. Interestingly, APOE-ε4 genotype was associated to higher BNP values, suggesting a putative interaction between genetic and biochemical markers in identifying people at risk for HF.

Presence of ApoE ε4 allele associated with thinner frontal cortex in middle age

The presence of an ApoE ε4 allele (ε4+) increases the risk of developing Alzheimer's disease (AD). Previous studies support an adverse relationship between ε4+ status and brain structure and function in mild cognitive impairment and AD; in contrast, the presence of an ε2 allele may be protective. Whether these findings reflect disease-related effects or pre-existing endophenotypes, however, remains unclear. The present study examined the influence of ApoE allele status on brain structure solely during middle-age in a large, national sample. Participants were 482 men, ages 51-59, from the Vietnam Era Twin Study of Aging (VETSA). T1-weighted images were used in volumetric segmentation and cortical surface reconstruction methods to measure regional volume and thickness. Primary linear mixed effects models predicted structural measures with ApoE status (ε3/3, ε2/3, ε3/4) and control variables for effects of site, non-independence of twin data, age, and average cranial vault or cortical thickness. Relative to the ε3/3 group, the ε3/4 group demonstrated significantly thinner cortex in superior frontal and left rostral and right caudal midfrontal regions; there were no significant effects of ε4 status on any temporal lobe measures. The ε2/3 group demonstrated significantly thicker right parahippocampal cortex relative to the ε3/3 group. The ApoE ε4 allele may influence cortical thickness in frontal areas, which are later developing regions thought to be more susceptible to the natural aging process. Previous conflicting findings for mesial temporal regions may be driven by the inclusion of older individuals, who may evidence preclinical manifestations of disease, and by unexamined moderators of ε4-related effects. The presence of the ε2 allele was related to thicker cortex, supporting a protective role. Ongoing follow-up of the VETSA sample may shed light on the potential for age- and disease-related mediation of the influence of ApoE allele status.

Patients with Alzheimer disease have altered transmitral flow: echocardiographic analysis of the vortex formation time

OBJECTIVE

There is considerable epidemiologic evidence that Alzheimer disease (AD) is linked to cardiovascular risk factors and associated with an increased risk of symptomatic left ventricular (LV) dysfunction. Formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. The vortex formation time (VFT) is an index of optimal conditions for vortex formation. We hypothesized that AD and its associated cardiovascular risk factors impair diastolic transmitral flow efficiency and, therefore, shift the VFT value out of its optimal range.

METHODS

Echocardiographic studies were performed on 45 participants in total: 22 patients with AD diagnosed according to the American Psychiatric Association's criteria and 23 age-matched individuals as a control group with cognitive function within normal limits.

RESULTS

The echocardiographic ratio of the early to atrial phases of the LV filling velocities was significantly lower in the AD group (mean +/- SD, 0.67 +/- 14) when compared with the control individuals (0.79 +/- 0.14; P = .003). The interventricular septum diastolic thickness, left ventricular posterior wall diastolic thickness, and right ventricular end-diastolic diameter were significantly higher in the AD group (P <or= 0.04). The mitral annular diameters in the control and AD groups were nearly identical (P = .725). The time-velocity integral of the E wave had a lower value in the AD group than in the control group (P = .05), whereas the VFT was significantly lower in the AD group (P = .018).

CONCLUSIONS

Our study suggests that patients with AD have impaired transmitral flow efficiency of diastolic filling, as measured by the VFT, compared with age-matched control individuals.

Cardiomyocyte contractile dysfunction in the APPswe/PS1dE9 mouse model of Alzheimer's disease

Objectives

Ample clinical and experimental evidence indicated that patients with Alzheimer's disease display a high incidence of cardiovascular events. This study was designed to examine myocardial histology, cardiomyocyte shortening, intracellular Ca²⁺ homeostasis and regulatory proteins, electrocardiogram, adrenergic response, endoplasmic reticulum (ER) stress and protein carbonyl formation in C57 wild-type (WT) mice and an APPswe/PS1dE9 transgenic (APP/PS1) model for Alzheimer's disease.

Methods

Cardiomyocyte mechanical properties were evaluated including peak shortening (PS), time-to-PS (TPS), time-to-relengthening (TR), maximal velocity of shortening and relengthening (±dL/dt), intracellular Ca²⁺ transient rise and decay.

Results

Little histological changes were observed in APP/PS1 myocardium. Cardiomyocytes from APP/PS1 but not APP or PS1 single mutation mice exhibited depressed PS, reduced±dL/dt, normal TPS and TR compared with WT mice_. Rise in intracellular Ca²⁺ was lower accompanied by unchanged resting/peak intracellular Ca²⁺ levels and intracellular Ca²⁺ decay in APP/PS1 mice. Cardiomyocytes from APP/PS1 mice exhibited a steeper decline in PS at high frequencies. The responsiveness to adrenergic agonists was dampened although β₁-adrenergic receptor expression was unchanged in APP/PS1 hearts. Expression of the Ca²⁺ regulatory protein phospholamban and protein carbonyl formation were downregulated and elevated, respectively, associated with unchanged SERCA2a, Na⁺-Ca²⁺ exchanger and ER stress markers in APP/PS1 hearts. Our further study revealed that antioxidant N-acetylcysteine attenuated the contractile dysfunction in APP/PS1 mice.

Conclusions

Our results depicted overt cardiomyocyte mechanical dysfunction in the APP/PS1 Alzheimer's disease model, possibly due to oxidative stress.

Frequency of subclinical heart disease in elderly persons with dementia

The authors compared the frequency of structural and functional heart abnormalities assessed using transthoracic echocardiography among persons with Alzheimer's disease, vascular dementia, stroke, and healthy control subjects. Compared with controls, patients with Alzheimer's disease were more likely to have aortic valve thickening, aortic valve regurgitation, left ventricular wall motion abnormalities, left ventricular hypertrophy, and reduced ejection fraction. Persons with vascular dementia were more likely to have aortic valve regurgitation, but mitral valve thickening and tricuspid valve regurgitation were also more frequent. In the absence of dementia, persons with stroke differed from controls by more frequent mitral valve calcifications. With the increasing prevalence of Alzheimer's disease and vascular dementia, clinicians have to be more attentive to the presence of structural heart disease and its complications in persons with these conditions.

Poststroke Dementia in the Elderly

Risk of dementia increases after stroke, and poststroke dementia (PSD) is an important cause of disability in the elderly. The prevalence rates of PSD vary from 12.2% to 31.8% within 3 months to 1 year after stroke, depending on patient populations and the diagnostic criteria used in the numerous studies. Incidence rates of PSD increase with time after the stroke. Although vascular lesions and white matter changes can explain the cognitive disorders seen in stroke patients, an underlying neurodegenerative disorder may contribute to the development of PSD. Cognitive decline may pre-date the stroke and follow a progressive course after the stroke. The vascular and degenerative processes involved share common environmental and genetic risk factors. This review explains the mechanisms of dementia in stroke patients and identifies predictive factors for PSD. The following points are successively considered: (i) demographic characteristics of the patients, including age and level of education; (ii) prestroke cognitive decline; (iii) vascular risk factors, including diabetes mellitus and prior strokes; (iv) stroke characteristics, including severity and location of the vascular lesion; (v) co-morbid disorders; and (vi) abnormalities on brain imaging, including location, size and number of vascular lesions, white matter changes and cerebral atrophy. Older age, prestroke cognitive decline, stroke recurrence, hypoxic-ischaemic disorders, left-side infarcts, strategic infarcts and white matter lesions appear to be the main predictive factors of PSD. Prevention of stroke should reduce the morbidity and mortality associated with PSD. In addition, management of PSD with secondary prevention treatments could reduce occurrence of further strokes. Cholinesterase inhibitors may be beneficial not only in Alzheimer's disease associated with cerebrovascular lesions, but also for the treatment of cholinergic dysfunction arising from pure vascular dementia. Better knowledge of the risk factors for PSD, including environmental and genetic factors, should increase the effectiveness of preventive strategies in patients with this condition.