39 research outputs found

    Obstructive Sleep Apnea Severity Affects Amyloid Burden in Cognitively Normal Elderly. A Longitudinal Study

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    Rationale: Recent evidence suggests that obstructive sleep apnea (OSA) may be a risk factor for developing mild cognitive impairment and Alzheimer’s disease. However, how sleep apnea affects longitudinal risk for Alzheimer’s disease is less well understood. Objectives: To test the hypothesis that there is an association between severity of OSA and longitudinal increase in amyloid burden in cognitively normal elderly. Methods: Data were derived from a 2-year prospective longitudinal study that sampled community-dwelling healthy cognitively normal elderly. Subjects were healthy volunteers between the ages of 55 and 90, were nondepressed, and had a consensus clinical diagnosis of cognitively normal. Cerebrospinal fluid amyloid β was measured using ELISA. Subjects received Pittsburgh compound B positron emission tomography scans following standardized procedures. Monitoring of OSA was completed using a home sleep recording device. Measurements and Main Results: We found that severity of OSA indices (AHIall [F1,88 = 4.26; P < 0.05] and AHI4% [F1,87 = 4.36; P < 0.05]) were associated with annual rate of change of cerebrospinal fluid amyloid β42 using linear regression after adjusting for age, sex, body mass index, and apolipoprotein E4 status. AHIall and AHI4% were not associated with increases in ADPiB-mask (Alzheimer’s disease vulnerable regions of interest Pittsburg compound B positron emission tomography mask) most likely because of the small sample size, although there was a trend for AHIall (F1,28 = 2.96, P = 0.09; and F1,28 = 2.32, not significant, respectively). Conclusions: In a sample of cognitively normal elderly, OSA was associated with markers of increased amyloid burden over the 2-year follow-up. Sleep fragmentation and/or intermittent hypoxia from OSA are likely candidate mechanisms. If confirmed, clinical interventions for OSA may be useful in preventing amyloid build-up in cognitively normal elderly

    Lower mortality risk in APOE4 carriers with normal cognitive ageing

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    Abstract Abnormal cognitive ageing, including dementia, poses serious challenges to health and social systems in ageing populations. As such, characterizing factors associated with abnormal cognitive ageing and developing needed preventive measures are of great importance. The ε4 allele of the Apolipoprotein E gene (APOE4) is a well-known genetic risk factor for late-onset Alzheimer’s disease. APOE4 carriers are also at elevated risk of cardiovascular diseases which are associated with increased risk of cognitive impairment. On the other hand, APOE4 is known to be associated with reduced risk of multiple common types of cancer—a major age-related disease and leading cause of mortality. We conducted the first-ever study of APOE4’s opposing effects on cognitive decline and mortality using competing risk models considering two types of death—death with high-amounts versus low-amounts of autopsy-assessed Alzheimer’s neuropathology. We observed that APOE4 was associated with decreased mortality risk in people who died with low amounts of Alzheimer’s-type neuropathology, but APOE4 was associated with increased mortality risk in people who died with high amounts of Alzheimer’s-type neuropathology, a major risk factor of cognitive impairment. Possible preventive measures of abnormal cognitive ageing are also discussed

    Effects of Memantine on Cerebrospinal Fluid Biomarkers of Neurofibrillary Pathology

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    Previous studies showed that memantine inhibits tau hyperphosphorylation in vitro. In this study, phosphorylated tau (P-tau) and total tau (T-tau) were measured before and after 6 month treatment with memantine in 12 subjects ranging from normal cognition with subjective memory complaints, through mild cognitive impairment to mild Alzheimer\u27s disease. Thirteen non-treated individuals served as controls. Treatment was associated with a reduction of P-tau in subjects with normal cognition. No treatment effects were seen among impaired individuals, suggesting that longer treatment time may be necessary to achieve biomarker effect in this group

    Obstructive Sleep Apnea Severity Affects Amyloid Burden in Cognitively Normal Elderly. A Longitudinal Study

    No full text
    Rationale: Recent evidence suggests that obstructive sleep apnea (OSA) may be a risk factor for developing mild cognitive impairment and Alzheimer’s disease. However, how sleep apnea affects longitudinal risk for Alzheimer’s disease is less well understood. Objectives: To test the hypothesis that there is an association between severity of OSA and longitudinal increase in amyloid burden in cognitively normal elderly. Methods: Data were derived from a 2-year prospective longitudinal study that sampled community-dwelling healthy cognitively normal elderly. Subjects were healthy volunteers between the ages of 55 and 90, were nondepressed, and had a consensus clinical diagnosis of cognitively normal. Cerebrospinal fluid amyloid β was measured using ELISA. Subjects received Pittsburgh compound B positron emission tomography scans following standardized procedures. Monitoring of OSA was completed using a home sleep recording device. Measurements and Main Results: We found that severity of OSA indices (AHIall [F1,88 = 4.26; P \u3c 0.05] and AHI4% [F1,87 = 4.36; P \u3c 0.05]) were associated with annual rate of change of cerebrospinal fluid amyloid β42 using linear regression after adjusting for age, sex, body mass index, and apolipoprotein E4 status. AHIall and AHI4% were not associated with increases in ADPiB-mask (Alzheimer’s disease vulnerable regions of interest Pittsburg compound B positron emission tomography mask) most likely because of the small sample size, although there was a trend for AHIall (F1,28 = 2.96, P = 0.09; and F1,28 = 2.32, not significant, respectively). Conclusions: In a sample of cognitively normal elderly, OSA was associated with markers of increased amyloid burden over the 2-year follow-up. Sleep fragmentation and/or intermittent hypoxia from OSA are likely candidate mechanisms. If confirmed, clinical interventions for OSA may be useful in preventing amyloid build-up in cognitively normal elderly
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