Sex-specific associations of serum cortisol with brain biomarkers of Alzheimer's risk

Emerging evidence implicates chronic psychological stress as a risk factor for Alzheimer's disease (AD). Herein, we examined the relationships between serum cortisol and multimodality brain AD biomarkers in 277 cognitively normal midlife individuals at risk for AD. Overall, higher cortisol was associated with lower total brain volume, lower glucose metabolism (CMRglc) in frontal cortex, and higher β-amyloid (Aβ) load in AD-vulnerable regions; and marginally associated with phosphocreatine to ATP ratios (PCr/ATP) in precuneus and parietal regions. Sex-specific modification effects were noted: in women, cortisol exhibited stronger associations with Aβ load and frontal CMRglc, the latter being more pronounced postmenopause. In men, cortisol exhibited stronger associations with gray matter volume and PCr/ATP measures. Higher cortisol was associated with poorer delayed memory in men but not in women. Results were adjusted for age, Apolipoprotein E (APOE) epsilon 4 status, midlife health factors, and hormone therapy use. These results suggest sex-specific neurophysiological responses to stress, and support a role for stress reduction in AD prevention.

Systematic review and meta-analysis of the effects of menopause hormone therapy on cognition

Introduction

Despite evidence from preclinical studies suggesting estrogen's neuroprotective effects, the use of menopausal hormone therapy (MHT) to support cognitive function remains controversial.

Methods

We used random-effect meta-analysis and multi-level meta-regression to derive pooled standardized mean difference (SMD) and 95% confidence intervals (C.I.) from 34 randomized controlled trials, including 14,914 treated and 12,679 placebo participants.

Results

Associations between MHT and cognitive function in some domains and tests of interest varied by formulation and treatment timing. While MHT had no overall effects on cognitive domain scores, treatment for surgical menopause, mostly estrogen-only therapy, improved global cognition (SMD=1.575, 95% CI 0.228, 2.921; P=0.043) compared to placebo. When initiated specifically in midlife or close to menopause onset, estrogen therapy was associated with improved verbal memory (SMD=0.394, 95% CI 0.014, 0.774; P=0.046), while late-life initiation had no effects. Overall, estrogen-progestogen therapy for spontaneous menopause was associated with a decline in Mini Mental State Exam (MMSE) scores as compared to placebo, with most studies administering treatment in a late-life population (SMD=-1.853, 95% CI -2.974, -0.733; P = 0.030). In analysis of timing of initiation, estrogen-progestogen therapy had no significant effects in midlife but was associated with improved verbal memory in late-life (P = 0.049). Duration of treatment >1 year was associated with worsening in visual memory as compared to shorter duration. Analysis of individual cognitive tests yielded more variable results of positive and negative effects associated with MHT.

Discussion

These findings suggest time-dependent effects of MHT on certain aspects of cognition, with variations based on formulation and timing of initiation, underscoring the need for further research with larger samples and more homogeneous study designs.

Systematic review and meta-analysis of the effects of menopause hormone therapy on risk of Alzheimer's disease and dementia

Introduction

Despite a large preclinical literature demonstrating neuroprotective effects of estrogen, use of menopausal hormone therapy (HT) for Alzheimer's disease (AD) risk reduction has been controversial. Herein, we conducted a systematic review and meta-analysis of HT effects on AD and dementia risk.

Methods

Our systematic search yielded 6 RCT reports (21,065 treated and 20,997 placebo participants) and 45 observational reports (768,866 patient cases and 5.5 million controls). We used fixed and random effect meta-analysis to derive pooled relative risk (RR) and 95% confidence intervals (C.I.) from these studies.

Results

Randomized controlled trials conducted in postmenopausal women ages 65 and older show an increased risk of dementia with HT use compared with placebo [RR = 1.38, 95% C.I. 1.16-1.64, p < 0.001], driven by estrogen-plus-progestogen therapy (EPT) [RR = 1.64, 95% C.I. 1.20-2.25, p = 0.002] and no significant effects of estrogen-only therapy (ET) [RR = 1.19, 95% C.I. 0.92-1.54, p = 0.18]. Conversely, observational studies indicate a reduced risk of AD [RR = 0.78, 95% C.I. 0.64-0.95, p = 0.013] and all-cause dementia [RR = .81, 95% C.I. 0.70-0.94, p = 0.007] with HT use, with protective effects noted with ET [RR = 0.86, 95% C.I. 0.77-0.95, p = 0.002] but not with EPT [RR = 0.910, 95% C.I. 0.775-1.069, p = 0.251]. Stratified analysis of pooled estimates indicates a 32% reduced risk of dementia with midlife ET [RR = 0.685, 95% C.I. 0.513-0.915, p = 0.010] and non-significant reductions with midlife EPT [RR = 0.775, 95% C.I. 0.474-1.266, p = 0.309]. Late-life HT use was associated with increased risk, albeit not significant [EPT: RR = 1.323, 95% C.I. 0.979-1.789, p = 0.069; ET: RR = 1.066, 95% C.I. 0.996-1.140, p = 0.066].

Discussion

These findings support renewed research interest in evaluating midlife estrogen therapy for AD risk reduction.

Systematic review of 31P-magnetic resonance spectroscopy studies of brain high energy phosphates and membrane phospholipids in aging and Alzheimer's disease

Many lines of evidence suggest that mitochondria have a central role in aging-related neurodegenerative diseases, such as Alzheimer's disease (AD). Mitochondrial dysfunction, cerebral energy dysmetabolism and oxidative damage increase with age, and are early event in AD pathophysiology and may precede amyloid beta (Aβ) plaques. In vivo probes of mitochondrial function and energy metabolism are therefore crucial to characterize the bioenergetic abnormalities underlying AD risk, and their relationship to pathophysiology and cognition. A majority of the research conducted in humans have used ¹⁸F-fluoro-deoxygluose (FDG) PET to image cerebral glucose metabolism (CMRglc), but key information regarding oxidative phosphorylation (OXPHOS), the process which generates 90% of the energy for the brain, cannot be assessed with this method. Thus, there is a crucial need for imaging tools to measure mitochondrial processes and OXPHOS in vivo in the human brain. ³¹Phosphorus-magnetic resonance spectroscopy (³¹P-MRS) is a non-invasive method which allows for the measurement of OXPHOS-related high-energy phosphates (HEP), including phosphocreatine (PCr), adenosine triphosphate (ATP), and inorganic phosphate (Pi), in addition to potential of hydrogen (pH), as well as components of phospholipid metabolism, such as phosphomonoesters (PMEs) and phosphodiesters (PDEs). Herein, we provide a systematic review of the existing literature utilizing the ³¹P-MRS methodology during the normal aging process and in patients with mild cognitive impairment (MCI) and AD, with an additional focus on individuals at risk for AD. We discuss the strengths and limitations of the technique, in addition to considering future directions toward validating the use of ³¹P-MRS measures as biomarkers for the early detection of AD.

In vivo Brain Estrogen Receptor Expression By Neuroendocrine Aging And Relationships With Gray Matter Volume, Bio-Energetics, and Clinical Symptomatology

17β-estradiol,the most biologically active estrogen, exerts wide-ranging effects in brain through its action on estrogen receptors (ERs), influencing higher-order cognitive function and neurobiological aging. However, our knowledge of ER expression and regulation by neuroendocrine aging in the living human brain is limited. This in vivo multi-modality neuroimaging study of healthy midlife women reveals progressively higher ER density over the menopause transition in estrogen-regulated networks. Effects were independent of age and plasma estradiol levels, and were highly consistent, correctly classifying all women as being post-menopausal or not. Higher ER density was generally associated with lower gray matter volume and blood flow, and with higher mitochondria ATP production, possibly reflecting compensatory mechanisms. Additionally, ER density predicted changes in thermoregulation, mood, cognition, and libido. Our data provide evidence that ER density impacts brainstructure, perfusion and energy production during female endocrine aging, with clinical implications for women's health.

Effects of sex and APOE ε4 genotype on brain mitochondrial high-energy phosphates in midlife individuals at risk for Alzheimer's disease: A 31Phosphorus MR spectroscopy study

Age, female sex, and APOE epsilon 4 (APOE4) genotype are the three greatest risk factors for late-onset Alzheimer's disease (AD). The convergence of these risks creates a hypometabolic AD-risk profile unique to women, which may help explain their higher lifetime risk of AD. Less is known about APOE4 effects in men, although APOE4 positive men also experience an increased AD risk. This study uses 31Phosphorus Magnetic Resonance Spectroscopy (31P-MRS) to examine effects of sex and APOE4 status on brain high-energy phosphates [adenosine triphosphate (ATP), phosphocreatine (PCr), inorganic phosphate (Pi)] and membrane phospholipids [phosphomonoesters (PME), phosphodiesters (PDE)] in 209 cognitively normal individuals at risk for AD, ages 40-65, 80% female, 46% APOE4 carriers (APOE4+). Women exhibited lower PCr/ATP and PCr/Pi levels than men in AD-vulnerable regions, including frontal, posterior cingulate, lateral and medial temporal cortex (multi-variable adjusted p≤0.037). The APOE4+ group exhibited lower PCr/ATP and PCr/Pi in frontal regions as compared to non-carriers (APOE4-) (multi-variable adjusted p≤0.005). Sex by APOE4 status interactions were observed in frontal regions (multi-variable adjusted p≤0.046), where both female groups and APOE4+ men exhibited lower PCr/ATP and PCr/Pi than APOE4- men. Among men, APOE4 homozygotes exhibited lower frontal PCr/ATP than heterozygotes and non-carriers. There were no significant effects of sex or APOE4 status on Pi/ATP and PME/PDE measures. Among midlife individuals at risk for AD, women exhibit lower PCr/ATP (e.g. higher ATP utilization) and lower PCr/Pi (e.g. higher energy demand) than age-controlled men, independent of APOE4 status. However, a double dose of APOE4 allele shifted men's brains to a similar metabolic range as women's brains. Examination of brain metabolic heterogeneity can support identification of AD-specific pathways within at-risk subgroups, further advancing both preventive and precision medicine for AD.

Post-traumatic stress symptoms and burnout in healthcare professionals working in neonatal intensive care units: Results from the STRONG study

BACKGROUND

Newborns' deaths and life-threatening conditions represent extremely stressful events for parents and professionals working in NICUs, facilitating the onset of secondary traumatic stress symptoms. The STRONG study aims to better understand the psychological impact on Italian NICUs staff of bereavement care.

METHODS

The STRONG (STress afteR lOss in NeonatoloGy) study is a cross-sectional study based on a web survey consisted of four sections: sociodemographic, CommuniCARE-Newborn questionnaire, the Maslach Burnout Inventory and the Impact of Event Scale-Revised.

RESULTS

227 NICU workers (42.7% nurses, 23.3% midwives, 22.2% physicians, 11.8% other HCPs) answered the survey. The hardest tasks were "communicating baby's death" and "informing on autopsy results"; 44.7% of HCPs did not receive formal training in communicating bad news, 44.2% 'learned from the field' by watching other colleagues; 41.2% declared that they do not have any communication strategy. More than 90% of professionals thought that training on bereavement care is necessary. The majority of HCPs showed some degree of post-traumatic stress symptoms: 34% medium and 35.3% severe. Professionals with training in bereavement care and/or in communication had less probability to develop stress symptoms. A multivariate analysis showed that higher levels of burnout were associated with 4 or more monthly losses and medium or severe stress symptoms. Having a well-defined communication strategy for breaking bad news was independently associated with a better personal accomplishment.

CONCLUSION

Dealing with newborns' deaths is a highly stressful task; professionals should receive proper support such as debriefing, psychological support and training in order to prevent post-traumatic stress symptoms and reduce professional burnout.

Sex and menopause impact 31P-Magnetic Resonance Spectroscopy brain mitochondrial function in association with 11C-PiB PET amyloid-beta load

Increasing evidence implicates sex and endocrine aging effects on brain bioenergetic aging in the greater lifetime risk of Alzheimer's disease (AD) in women. We conducted 31Phosphorus Magnetic Resonance Spectroscopy (31P-MRS) to assess the impact of sex and menopause on brain high-energy phosphates [adenosine triphosphate (ATP), phosphocreatine (PCr), inorganic phosphate (Pi)] and membrane phospholipids [phosphomonoesters/phosphodiesters (PME/PDE)] in 216 midlife cognitively normal individuals at risk for AD, 80% female. Ninety-seven participants completed amyloid-beta (Aβ) 11C-PiB PET. Women exhibited higher ATP utilization than men in AD-vulnerable frontal, posterior cingulate, fusiform, medial and lateral temporal regions (p < 0.001). This profile was evident in frontal cortex at the pre-menopausal and peri-menopausal stage and extended to the other regions at the post-menopausal stage (p = 0.001). Results were significant after multi-variable adjustment for age, APOE-4 status, midlife health indicators, history of hysterectomy/oophorectomy, use of menopause hormonal therapy, and total intracranial volume. While associations between ATP/PCr and Aβ load were not significant, individuals with the highest Aβ load were post-menopausal and peri-menopausal women with ATP/PCr ratios in the higher end of the distribution. No differences in Pi/PCr, Pi/ATP or PME/PDE were detected. Outcomes are consistent with dynamic bioenergetic brain adaptations that are associated with female sex and endocrine aging.

Phosphorus metabolism in the brain of cognitively normal midlife individuals at risk for Alzheimer's disease

BACKGROUND

Neurometabolic abnormalities and amyloid-beta plaque deposition are important early pathophysiologic changes in Alzheimer's disease (AD). This study investigated the relationship between high-energy phosphorus-containing metabolites, glucose uptake, and amyloid plaque using phosphorus magnetic resonance spectroscopy (³¹P-MRS) and positron emission tomography (PET).

METHODS

We measured ³¹P-MRS, fluorodeoxyglucose (FDG)-PET, and Pittsburgh Compound B (PiB)-PET in a cohort of 20 cognitively normal middle-aged adults at risk for AD. We assessed ³¹P-MRS reliability by scanning a separate cohort of 13 healthy volunteers twice each. We calculated the coefficient-of-variation (CV) of metabolite ratios phosphocreatine-to-adenosine triphosphate (PCr/α-ATP), inorganic phosphate (Pi)-to-α-ATP, and phosphomonoesters-to-phosphodiesters (PME/PDE), and pH in pre-defined brain regions. We performed linear regression analysis to determine the relationship between ³¹P measurements and tracer uptake, and Dunn's multiple comparison tests to investigate regional differences in phosphorus metabolism. Finally, we performed linear regression analysis on ³¹P-MRS measurements in both cohorts to investigate the relationship of phosphorus metabolism with age.

RESULTS

Most regional ³¹P metabolite ratio and pH inter- and intra-day CVs were well below 10%. There was an inverse relationship between FDG-SUV levels and metabolite ratios PCr/α-ATP, Pi/α-ATP, and PME/PDE in several brain regions in the AD risk group. There were also several regional differences among ³¹P metabolites and pH in the AD risk group including elevated PCr/α-ATP, depressed PME/PDE, and elevated pH in the temporal cortices. Increased PCr/α-ATP throughout the brain was associated with aging.

CONCLUSIONS

Phosphorus spectroscopy in the brain can be performed with high repeatability. Phosphorus metabolism varies with region and age, and is related to glucose uptake in adults at risk for AD. Phosphorus spectroscopy may be a valuable approach to study early changes in brain energetics in high-risk populations.

Ovarian steroid hormones: A long overlooked but critical contributor to brain aging and Alzheimer’s disease

Ovarian hormones, particularly 17β-estradiol, are involved in numerous neurophysiological and neurochemical processes, including those subserving cognitive function. Estradiol plays a key role in the neurobiology of aging, in part due to extensive interconnectivity of the neural and endocrine system. This aspect of aging is fundamental for women’s brains as all women experience a drop in circulating estradiol levels in midlife, after menopause. Given the importance of estradiol for brain function, it is not surprising that up to 80% of peri-menopausal and post-menopausal women report neurological symptoms including changes in thermoregulation (vasomotor symptoms), mood, sleep, and cognitive performance. Preclinical evidence for neuroprotective effects of 17β-estradiol also indicate associations between menopause, cognitive aging, and Alzheimer’s disease (AD), the most common cause of dementia affecting nearly twice more women than men. Brain imaging studies demonstrated that middle-aged women exhibit increased indicators of AD endophenotype as compared to men of the same age, with onset in perimenopause. Herein, we take a translational approach to illustrate the contribution of ovarian hormones in maintaining cognition in women, with evidence implicating menopause-related declines in 17β-estradiol in cognitive aging and AD risk. We will review research focused on the role of endogenous and exogenous estrogen exposure as a key underlying mechanism to neuropathological aging in women, with a focus on whether brain structure, function and neurochemistry respond to hormone treatment. While still in development, this research area offers a new sex-based perspective on brain aging and risk of AD, while also highlighting an urgent need for better integration between neurology, psychiatry, and women’s health practices.

Endogenous and Exogenous Estrogen Exposures: How Women’s Reproductive Health Can Drive Brain Aging and Inform Alzheimer’s Prevention

After advanced age, female sex is the major risk factor for late-onset Alzheimer’s disease (AD), the most common cause of dementia affecting over 24 million people worldwide. The prevalence of AD is higher in women than in men, with postmenopausal women accounting for over 60% of all those affected. While most research has focused on gender-combined risk, emerging data indicate sex and gender differences in AD pathophysiology, onset, and progression, which may help account for the higher prevalence in women. Notably, AD-related brain changes develop during a 10–20 year prodromal phase originating in midlife, thus proximate with the hormonal transitions of endocrine aging characteristic of the menopause transition in women. Preclinical evidence for neuroprotective effects of gonadal sex steroid hormones, especially 17β-estradiol, strongly argue for associations between female fertility, reproductive history, and AD risk. The level of gonadal hormones to which the female brain is exposed changes considerably across the lifespan, with relevance to AD risk. However, the neurobiological consequences of hormonal fluctuations, as well as that of hormone therapies, are yet to be fully understood. Epidemiological studies have yielded contrasting results of protective, deleterious and null effects of estrogen exposure on dementia risk. In contrast, brain imaging studies provide encouraging evidence for positive associations between greater cumulative lifetime estrogen exposure and lower AD risk in women, whereas estrogen deprivation is associated with negative consequences on brain structure, function, and biochemistry. Herein, we review the existing literature and evaluate the strength of observed associations between female-specific reproductive health factors and AD risk in women, with a focus on the role of endogenous and exogenous estrogen exposures as a key underlying mechanism. Chief among these variables are reproductive lifespan, menopause status, type of menopause (spontaneous vs. induced), number of pregnancies, and exposure to hormonal therapy, including hormonal contraceptives, hormonal therapy for menopause, and anti-estrogen treatment. As aging is the greatest risk factor for AD followed by female sex, understanding sex-specific biological pathways through which reproductive history modulates brain aging is crucial to inform preventative and therapeutic strategies for AD.

A tale of two systems: Lessons learned from female mid-life aging with implications for Alzheimer's prevention & treatment

Neurological aging is frequently viewed as a linear process of decline, whereas in reality, it is a dynamic non-linear process. The dynamic nature of neurological aging is exemplified during midlife in the female brain. To investigate fundamental mechanisms of midlife aging that underlie risk for development of Alzheimer's disease (AD) in late life, we investigated the brain at greatest risk for the disease, the aging female brain. Outcomes of our research indicate that mid-life aging in the female is characterized by the emergence of three phases: early chronological (pre-menopause), endocrinological (peri-menopause) and late chronological (post-menopause) aging. The endocrinological aging program is sandwiched between early and late chronological aging. Throughout the three stages of midlife aging, two systems of biology, metabolic and immune, are tightly integrated through a network of signaling cascades. The network of signaling between these two systems of biology underlie an orchestrated sequence of adaptative starvation responses that shift the brain from near exclusive dependence on a single fuel, glucose, to utilization of an auxiliary fuel derived from lipids, ketone bodies. The dismantling of the estrogen control of glucose metabolism during mid-life aging is a critical contributor to the shift in fuel systems and emergence of dynamic neuroimmune phenotype. The shift in fuel reliance, puts the largest reservoir of local fatty acids, white matter, at risk for catabolism as a source of lipids to generate ketone bodies through astrocytic beta oxidation. APOE4 genotype accelerates the tipping point for emergence of the bioenergetic crisis. While outcomes derived from research conducted in the female brain are not directly translatable to the male brain, the questions addressed in a female centric program of research are directly applicable to investigation of the male brain. Like females, males with AD exhibit deficits in the bioenergetic system of the brain, activation of the immune system and hallmark Alzheimer's pathologies. The drivers and trajectory of mechanisms underlying neurodegeneration in the male brain will undoubtedly share common aspects with the female in addition to factors unique to the male. Preclinical and clinical evidence indicate that midlife endocrine aging can also be a transitional bridge to autoimmune disorders. Collectively, the data indicate that endocrinological aging is a critical period "tipping point" in midlife which can initiate emergence of the prodromal stage of late-onset-Alzheimer's disease. Interventions that target both immune and metabolic shifts that occur during midlife aging have the potential to alter the trajectory of Alzheimer's risk in late life. Further, to achieve precision medicine for AD, chromosomal sex is a critical variable to consider along with APOE genotype, other genetic risk factors and stage of disease.

Sex-Driven Differences in the Effectiveness of Individualized Clinical Management of Alzheimer's Disease Risk

BACKGROUND

The Comparative Effectiveness Dementia and Alzheimer's Registry (CEDAR) trial demonstrated that individualized, multi-domain interventions improved cognition and reduced the risk of Alzheimer's disease (AD). As biological sex is a significant risk factor for AD, it is essential to explore the differential effectiveness of targeted clinical interventions in women vs. men.

METHODS

Patients were recruited from an Alzheimer's Prevention Clinic. Subjects with normal cognition, subjective cognitive decline, or asymptomatic preclinical AD were classified as "Prevention". Subjects with mild cognitive impairment due to AD or mild AD were classified as "Early Treatment." The primary outcome was the change from baseline to 18-months on the modified-Alzheimer's Prevention Cognitive Composite. Secondary outcomes included a cognitive aging composite, AD and cardiovascular (CV) risk scales, and serum biomarkers. Subjects who adhered to > 60% of recommendations in the CEDAR trial were included in this a priori sub-group analysis to examine whether individualized intervention effects were modified by sex (n=80).

RESULTS

In the Prevention group, both women (p=0.0205) and men (p=0.0044) demonstrated improvements in cognition with no sex differences (p=0.5244). In the Early Treatment group, there were also no significant sex differences in cognition (p=0.3299). In the Prevention group, women demonstrated greater improvements in the Multi-Ethnic Study of Atherosclerosis risk score (MESA-RS) than men (difference=1.5, p=0.0013). Women in the Early Treatment group demonstrated greater improvements in CV Risk Factors, Aging and Incidence of Dementia (CAIDE) risk score (difference=2.3, p=0.0067), and the MESA-RS (difference=4.1, p<0.001).

CONCLUSIONS

Individualized multi-domain interventions are equally effective at improving cognition in women and men. However, personally-tailored interventions led to greater improvements in calculated AD and CV risk, and CV blood biomarkers, in women compared to men. Future study in larger cohorts is necessary to further define sex differences in AD risk reduction in clinical practice.

Association of Reproductive History With Brain MRI Biomarkers of Dementia Risk in Midlife

BACKGROUND AND OBJECTIVES

To examine associations between indicators of estrogen exposure from women's reproductive history and brain MRI biomarkers of Alzheimer disease (AD) in midlife.

METHODS

We evaluated 99 cognitively normal women 52 ± 6 years of age and 29 men 52 ± 7 years of age with reproductive history data, neuropsychological testing, and volumetric MRI scans. We used multiple regressions to examine associations among reproductive history indicators, voxel-wise gray matter volume (GMV), and memory and global cognition scores, adjusting for demographics and midlife health indicators. Exposure variables were menopause status, age at menarche, age at menopause, reproductive span, hysterectomy status, number of children and pregnancies, and use of menopause hormonal therapy (HT) and hormonal contraceptives (HC).

RESULTS

All menopausal groups exhibited lower GMV in AD-vulnerable regions compared to men, with perimenopausal and postmenopausal groups also exhibiting lower GMV in temporal cortex compared to the premenopausal group. Reproductive span, number of children and pregnancies, and use of HT and HC were positively associated with GMV, chiefly in temporal cortex, frontal cortex, and precuneus, independent of age, APOE ε4 status, and midlife health indicators. Although reproductive history indicators were not directly associated with cognitive measures, GMV in temporal regions was positively associated with memory and global cognition scores.

DISCUSSION

Reproductive history events signaling more estrogen exposure such as premenopausal status, longer reproductive span, higher number of children, and use of HT and HC were associated with larger GMV in women in midlife. Further studies are needed to elucidate sex-specific biological pathways through which reproductive history influences cognitive aging and AD risk.

Menopause impacts human brain structure, connectivity, energy metabolism, and amyloid-beta deposition

All women undergo the menopause transition (MT), a neuro-endocrinological process that impacts aging trajectories of multiple organ systems including brain. The MT occurs over time and is characterized by clinically defined stages with specific neurological symptoms. Yet, little is known of how this process impacts the human brain. This multi-modality neuroimaging study indicates substantial differences in brain structure, connectivity, and energy metabolism across MT stages (pre-menopause, peri-menopause, and post-menopause). These effects involved brain regions subserving higher-order cognitive processes and were specific to menopausal endocrine aging rather than chronological aging, as determined by comparison to age-matched males. Brain biomarkers largely stabilized post-menopause, and gray matter volume (GMV) recovered in key brain regions for cognitive aging. Notably, GMV recovery and in vivo brain mitochondria ATP production correlated with preservation of cognitive performance post-menopause, suggesting adaptive compensatory processes. In parallel to the adaptive process, amyloid-β deposition was more pronounced in peri-menopausal and post-menopausal women carrying apolipoprotein E-4 (APOE-4) genotype, the major genetic risk factor for late-onset Alzheimer's disease, relative to genotype-matched males. These data show that human menopause is a dynamic neurological transition that significantly impacts brain structure, connectivity, and metabolic profile during midlife endocrine aging of the female brain.

ALIF in the correction of spinal sagittal misalignment. A systematic review of literature

PURPOSE

We aim at analysing the impact of anterior lumbar interbody fusion (ALIF) in restoring the main spinopelvic parameters, along with its potentials and limitations in correcting sagittal imbalance.

MATERIALS AND METHODS

The 2009 PRISMA flow chart was used to systematically review the literature; 27 papers were eventually selected. The following spinopelvic parameters were observed: pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), segmental lumbar lordosis (LLseg) and sagittal vertical axis (SVA). Papers reporting on hyperlordotic cages (HLC) were analysed separately. The indirect decompression potential of ALIF was also assessed. The clinical outcome was obtained by collecting visual analogue scale (VAS) for back and leg pain and Oswestry Disability Index (ODI) scores. Global fusion rate and main complications were collected.

RESULTS

PT, SS, LL, LLseg and SVA spinopelvic parameters all improved postoperatively by - 4.3 ± 5.2°, 3.9 ± 4.5°, 10.6 ± 12.5°, 6.7 ± 3.5° and 51.1 ± 44.8 mm, respectively. HLC were statistically more effective in restoring LL and LLseg (p < 0.05). Postoperative disc height, anterior disc height, posterior disc height and foraminal height, respectively, increased by 58.5%, 87.2%, 80.9% and 18.1%. Postoperative improvements were observed in VAS back and leg and ODI scores (p < 0.05). The global fusion rate was 94.5 ± 5.5%; the overall complication rate was 13%.

CONCLUSION

When managing sagittal imbalance, ALIF can be considered as a valid technique to achieve the correct spinopelvic parameters based on preoperative planning. This technique permits to obtain an optimal LL distribution and a solid anterior column support, with lower complications and higher fusion rates when compared to posterior osteotomies.

Safety and target engagement profile of two oxaloacetate doses in Alzheimer's patients

INTRODUCTION

Brain bioenergetics are defective in Alzheimer's disease (AD). Preclinical studies find oxaloacetate (OAA) enhances bioenergetics, but human safety and target engagement data are lacking.

METHODS

We orally administered 500 or 1000 mg OAA, twice daily for 1 month, to AD participants (n = 15 each group) and monitored safety and tolerability. To assess brain metabolism engagement, we performed fluorodeoxyglucose positron emission tomography (FDG PET) and magnetic resonance spectroscopy before and after the intervention. We also assessed pharmacokinetics and cognitive performance.

RESULTS

Both doses were safe and tolerated. Compared to the lower dose, the higher dose benefited FDG PET glucose uptake across multiple brain regions (P < .05), and the higher dose increased parietal and frontoparietal glutathione (P < .05). We did not demonstrate consistent blood level changes and cognitive scores did not improve.

CONCLUSIONS

1000 mg OAA, taken twice daily for 1 month, is safe in AD patients and engages brain energy metabolism.

Sex-driven modifiers of Alzheimer risk: A multimodality brain imaging study

OBJECTIVE

To investigate sex differences in late-onset Alzheimer disease (AD) risks by means of multimodality brain biomarkers (β-amyloid load via ¹¹C-Pittsburgh compound B [PiB] PET, neurodegeneration via ¹⁸F-fluorodeoxyglucose [FDG] PET and structural MRI).

METHODS

We examined 121 cognitively normal participants (85 women and 36 men) 40 to 65 years of age with clinical, laboratory, neuropsychological, lifestyle, MRI, FDG- and PiB-PET examinations. Several clinical (e.g., age, education, APOE status, family history), medical (e.g., depression, diabetes mellitus, hyperlipidemia), hormonal (e.g., thyroid disease, menopause), and lifestyle AD risk factors (e.g., smoking, diet, exercise, intellectual activity) were assessed. Statistical parametric mapping and least absolute shrinkage and selection operator regressions were used to compare AD biomarkers between men and women and to identify the risk factors associated with sex-related differences.

RESULTS

Groups were comparable on clinical and cognitive measures. After adjustment for each modality-specific confounders, the female group showed higher PiB β-amyloid deposition, lower FDG glucose metabolism, and lower MRI gray and white matter volumes compared to the male group (p < 0.05, family-wise error corrected for multiple comparisons). The male group did not show biomarker abnormalities compared to the female group. Results were independent of age and remained significant with the use of age-matched groups. Second to female sex, menopausal status was the predictor most consistently and strongly associated with the observed brain biomarker differences, followed by hormone therapy, hysterectomy status, and thyroid disease.

CONCLUSION

Hormonal risk factors, in particular menopause, predict AD endophenotype in middle-aged women. These findings suggest that the window of opportunity for AD preventive interventions in women is early in the endocrine aging process.

Fusion rate and influence of surgery-related factors in lumbar interbody arthrodesis for degenerative spine diseases: a meta-analysis and systematic review

The aim of this meta-analysis and systematic review is to summarize and critically analyze the influence of surgery-related factors in lumbar interbody fusion for degenerative spine diseases. A systematic review of the literature was carried out with a primary search being performed on Medline through PubMed. The 2009 PRISMA flowchart and checklist were taken into account. Sixty-seven articles were included in the analysis: 48 studies were level IV of evidence, whereas 19 were level III. All interbody fusion techniques analyzed have proved to reach a good fusion rate. An overall mean fusion rate of 93% (95% CI 92-95%, p < 0.001) was estimated pooling the selected studies. The influence of sagittal parameters and cages features in fusion rate was not clear. Autograft is considered the gold standard material. The use of synthetic bone substitutes and biological factors alone or combined with bone graft have shown conflicting results. Low level of evidence studies and high heterogeneity (χ² = 271.4, df = 72, p < 0.001; I² = 73.5%, τ² = 0.05) in data analysis could result in the risk of bias. Further high-quality studies would better clarify these results in the future.

Individualized clinical management of patients at risk for Alzheimer's dementia

INTRODUCTION

Multidomain intervention for Alzheimer's disease (AD) risk reduction is an emerging therapeutic paradigm.

METHODS

Patients were prescribed individually tailored interventions (education/pharmacologic/nonpharmacologic) and rated on compliance. Normal cognition/subjective cognitive decline/preclinical AD was classified as Prevention. Mild cognitive impairment due to AD/mild-AD was classified as Early Treatment. Change from baseline to 18 months on the modified Alzheimer's Prevention Cognitive Composite (primary outcome) was compared against matched historical control cohorts. Cognitive aging composite (CogAging), AD/cardiovascular risk scales, and serum biomarkers were secondary outcomes.

RESULTS

One hundred seventy-four were assigned interventions (age 25-86). Higher-compliance Prevention improved more than both historical cohorts (P = .0012, P < .0001). Lower-compliance Prevention also improved more than both historical cohorts (P = .0088, P < .0055). Higher-compliance Early Treatment improved more than lower compliance (P = .0007). Higher-compliance Early Treatment improved more than historical cohorts (P < .0001, P = .0428). Lower-compliance Early Treatment did not differ (P = .9820, P = .1115). Similar effects occurred for CogAging. AD/cardiovascular risk scales and serum biomarkers improved.

DISCUSSION

Individualized multidomain interventions may improve cognition and reduce AD/cardiovascular risk scores in patients at-risk for AD dementia.

Sex and Gender Driven Modifiers of Alzheimer's: The Role for Estrogenic Control Across Age, Race, Medical, and Lifestyle Risks

Research indicates that after advanced age, the major risk factor for late-onset Alzheimer’s disease (AD) is female sex. Out of every three AD patients, two are females with postmenopausal women contributing to over 60% of all those affected. Sex- and gender-related differences in AD have been widely researched and several emerging lines of evidence point to different vulnerabilities that contribute to dementia risk. Among those being considered, it is becoming widely accepted that gonadal steroids contribute to the gender disparity in AD, as evidenced by the “estrogen hypothesis.” This posits that sex hormones, 17β-estradiol in particular, exert a neuroprotective effect by shielding females’ brains from disease development. This theory is further supported by recent findings that the onset of menopause is associated with the emergence of AD-related brain changes in women in contrast to men of the same age. In this review, we discuss genetic, medical, societal, and lifestyle risk factors known to increase AD risk differently between the genders, with a focus on the role of hormonal changes, particularly declines in 17β-estradiol during the menopause transition (MT) as key underlying mechanisms.

Clinical Application of APOE in Alzheimer's Prevention: A Precision Medicine Approach

Population-attributable risk models estimate that up to one-third of Alzheimer's disease (AD) cases may be preventable through risk factor modification. The field of AD prevention has largely focused on addressing these factors through universal risk reduction strategies for the general population. However, targeting these strategies in a clinical precision medicine fashion, including the use of genetic risk factors, allows for potentially greater impact on AD risk reduction. Apolipoprotein E (APOE), and specifically the APOE ε4 variant, is one of the most well-established genetic influencers on late-onset AD risk. In this review, we evaluate the impact of APOE ε4 carrier status on AD prevention interventions, including lifestyle, nutrigenomic, pharmacogenomic, AD comorbidities, and other biological and behavioral considerations. Using a clinical precision medicine strategy that incorporates APOE ε4 carrier status may provide a highly targeted and distinct approach to AD prevention with greater potential for success.

Sleep oscillation-specific associations with Alzheimer's disease CSF biomarkers: novel roles for sleep spindles and tau

BACKGROUND

Based on associations between sleep spindles, cognition, and sleep-dependent memory processing, here we evaluated potential relationships between levels of CSF Aβ42, P-tau, and T-tau with sleep spindle density and other biophysical properties of sleep spindles in a sample of cognitively normal elderly individuals.

METHODS

One-night in-lab nocturnal polysomnography (NPSG) and morning to early afternoon CSF collection were performed to measure CSF Aβ42, P-tau and T-tau. Seven days of actigraphy were collected to assess habitual total sleep time.

RESULTS

Spindle density during NREM stage 2 (N2) sleep was negatively correlated with CSF Aβ42, P-tau and T-tau. From the three, CSF T-tau was the most significantly associated with spindle density, after adjusting for age, sex and ApoE4. Spindle duration, count and fast spindle density were also negatively correlated with T-tau levels. Sleep duration and other measures of sleep quality were not correlated with spindle characteristics and did not modify the associations between sleep spindle characteristics and the CSF biomarkers of AD.

CONCLUSIONS

Reduced spindles during N2 sleep may represent an early dysfunction related to tau, possibly reflecting axonal damage or altered neuronal tau secretion, rendering it a potentially novel biomarker for early neuronal dysfunction. Given their putative role in memory consolidation and neuroplasticity, sleep spindles may represent a mechanism by which tau impairs memory consolidation, as well as a possible target for therapeutic interventions in cognitive decline.

Increased Alzheimer's risk during the menopause transition: A 3-year longitudinal brain imaging study

Two thirds of all persons with late-onset Alzheimer's disease (AD) are women. Identification of sex-based molecular mechanisms underpinning the female-based prevalence of AD would advance development of therapeutic targets during the prodromal AD phase when prevention or delay in progression is most likely to be effective. This 3-year brain imaging study examines the impact of the menopausal transition on Alzheimer's disease (AD) biomarker changes [brain β-amyloid load via 11C-PiB PET, and neurodegeneration via 18F-FDG PET and structural MRI] and cognitive performance in midlife. Fifty-nine 40-60 year-old cognitively normal participants with clinical, neuropsychological, and brain imaging exams at least 2 years apart were examined. These included 41 women [15 premenopausal controls (PRE), 14 perimenopausal (PERI), and 12 postmenopausal women (MENO)] and 18 men. We used targeted minimum loss-based estimation to evaluate AD biomarker and cognitive changes. Older age was associated with baseline Aβ and neurodegeneration markers, but not with rates of change in these biomarkers. APOE4 status influenced change in Aβ load, but not neurodegenerative changes. Longitudinally, MENO and PERI groups showed declines in estrogen-dependent memory tests as compared to men (p < .04). Adjusting for age, APOE4 status, and vascular risk confounds, the MENO and PERI groups exhibited higher rates of CMRglc decline as compared to males (p ≤ .015). The MENO group exhibited the highest rate of hippocampal volume loss (p's ≤ .001), and higher rates of Aβ deposition than males (p < .01). CMRglc decline exceeded Aβ and atrophy changes in all female groups vs. men. These findings indicate emergence and progression of a female-specific hypometabolic AD-endophenotype during the menopausal transition. These findings suggest that the optimal window of opportunity for therapeutic intervention to prevent or delay progression of AD endophenotype in women is early in the endocrine aging process.

The clinical practice of risk reduction for Alzheimer's disease: A precision medicine approach

Like virtually all age-related chronic diseases, late-onset Alzheimer's disease (AD) develops over an extended preclinical period and is associated with modifiable lifestyle and environmental factors. We hypothesize that multimodal interventions that address many risk factors simultaneously and are individually tailored to patients may help reduce AD risk. We describe a novel clinical methodology used to evaluate and treat patients at two Alzheimer's Prevention Clinics. The framework applies evidence-based principles of clinical precision medicine to tailor individualized recommendations, follow patients longitudinally to continually refine the interventions, and evaluate N-of-1 effectiveness (trial registered at ClinicalTrials.gov NCT03687710). Prior preliminary results suggest that the clinical practice of AD risk reduction is feasible, with measurable improvements in cognition and biomarkers of AD risk. We propose using these early findings as a foundation to evaluate the comparative effectiveness of personalized risk management within an international network of clinician researchers in a cohort study possibly leading to a randomized controlled trial.

Associations of lifestyle and vascular risk factors with Alzheimer's brain biomarker changes during middle age: a 3-year longitudinal study in the broader New York City area

OBJECTIVE

To investigate the associations between lifestyle and vascular risk factors and changes in Alzheimer's disease (AD) biomarkers (beta-amyloid load via ¹¹C-PiB PET, glucose metabolism via ¹⁸F-FDG PET and neurodegeneration via structural MRI) and global cognition in middle-aged asymptomatic participants at risk for AD.

DESIGN

Prospective, longitudinal.

SETTING

The study was conducted at New York University Langone/Weill Cornell Medical Centres in New York City.

PARTICIPANTS

Seventy cognitively normal participants from multiple community sources, aged 30-60 years with lifestyle measures (diet, intellectual activity and physical activity), vascular risk measures and two imaging biomarkers visits over at least 2 years, were included in the study.

OUTCOME MEASURES

We examined MRI-based cortical thickness, fluoro-deoxy-glucose (FDG) glucose metabolism and PiB beta-amyloid in AD-vulnerable regions. A global cognitive z-score served as our summary cognition measure. We used regression change models to investigate the associations of clinical, lifestyle and vascular risk measures with changes in AD biomarkers and global cognition.

RESULTS

Diet influenced changes in glucose metabolism, but not amyloid or cortical thickness changes. With and without accounting for demographic measures, vascular risk and baseline FDG measures, lower adherence to a Mediterranean-style diet was associated with faster rates of FDG decline in the posterior cingulate cortex (p≤0.05) and marginally in the frontal cortex (p=0.07). None of the other lifestyle variables or vascular measures showed associations with AD biomarker changes. Higher baseline plasma homocysteine was associated with faster rates of decline in global cognition, with and without accounting for lifestyle and biomarker measures (p=0.048). None of the lifestyle variables were associated with cognition.

CONCLUSIONS

Diet influenced brain glucose metabolism in middle-aged participants, while plasma homocysteine explained variability in cognitive performance. These findings suggest that these modifiable risk factors affect AD risk through different pathways and support further investigation of risk reduction strategies in midlife.

Utility of the NIH Toolbox for assessment of prodromal Alzheimer's disease and dementia

Introduction

The NIH Toolbox Cognition Battery (NIHTB-CB) is a computer-based protocol not yet validated for clinical assessment.

Methods

We administered the NIHTB-CB and traditional neuropsychological tests to 247 Memory Disorders and Alzheimer's Prevention Clinic patients with subjective cognitive decline, mild cognitive impairment, mild dementia due to Alzheimer's disease, and normal cognition. Principal component analysis, partial correlations, and univariate general linear model tests were performed to assess construct validity. Discriminant function analyses compared classification accuracy.

Results

Principal component analysis identified three conceptually coherent factors: memory (MEM_NIH), executive function (EF_NIH), and crystallized intelligence (CI_NIH). These factors were strongly associated with corresponding traditional tests and differed across diagnostic groups as expected. Both NIHTB and traditional batteries yielded strong overall discriminative ability (>80%).

Discussion

The NIHTB-CB is a valid method to assess neurocognitive domains pertinent to aging and dementia and has utility for applications in a memory clinic setting.

Precision Medicine for Alzheimer's Disease Prevention

Precision medicine is an approach to medical treatment and prevention that takes into account individual variability in genes, environment, and lifestyle and allows for personalization that is based on factors that may affect the response to treatment. Several genetic and epigenetic risk factors have been shown to increase susceptibility to late-onset Alzheimer's disease (AD). As such, it may be beneficial to integrate genetic risk factors into the AD prevention approach, which in the past has primarily been focused on universal risk-reduction strategies for the general population rather than individualized interventions in a targeted fashion. This review discusses examples of a "one-size-fits-all" versus clinical precision medicine AD prevention strategy, in which the precision medicine approach considers two genes that can be commercially sequenced for polymorphisms associated with AD, apolipoprotein E (APOE), and methylenetetrahydrofolate reductase (MTHFR). Comparing these two distinct approaches provides support for a clinical precision medicine prevention strategy, which may ultimately lead to more favorable patient outcomes as the interventions are targeted to address individualized risks.

Using social media to disseminate education about Alzheimer's prevention & treatment: a pilot study on Alzheimer's universe (www.AlzU.org)

Background

The use of social media may be a valuable tool for dissemination of patient education interventions. However, in Alzheimer's disease (AD), little data exists about the effectiveness, associated cost, or conditions for utilization.

Methods

Alzheimer's Universe (www.AlzU.org) is an online educational portal that provides evidence-based educational content for the public and a variety of activities related to optimizing AD management. The primary goal of our study was to assess the effectiveness of using the social media platform Facebook.com as a tool to recruit subjects to visit AlzU.org via targeted advertising and evaluate the associated costs. Secondary outcomes included AlzU.org join rates, lesson and activity completion rates, user demographics and attitudes about the education research platform.

Results

A total of $706 generated 4268 visits to AlzU.org via a series of page posts promoted with targeted advertising to individuals with previously expressed interest in 'Alzheimer's disease,' to those who had 'liked' the Alzheimer's Association page, and followers of www.facebook.com/AlzheimersDisease. Advertising used different promotional taglines in the Facebook Advertising manager tool using 'Cost Per Click' and the 'Optimized for Engagement' settings. Across all strategies combined, 503 visitors joined AlzU.org (11.8% join rate), 412 engaged with at least one lesson/activity (82%), and 100 completed all available lessons and activities (19.8%). Users were primarily women (79.8%) and the most common age group was 50's (43.3%, range 22-92). The majority joined AlzU.org to learn more about AD prevention or treatment (66.3% and 65.3%, respectively). Over 90% were satisfied with their experience.

Discussion

Subjects were quickly and cost-effectively recruited to AlzU.org. Completion rates of education content and activities were adequate, and subjects were highly satisfied with their experiences. Overall, targeted advertising on Facebook.com was an effective means of disseminating AD education online.

Mediterranean diet and 3-year Alzheimer brain biomarker changes in middle-aged adults

OBJECTIVE

To examine in a 3-year brain imaging study the effects of higher vs lower adherence to a Mediterranean-style diet (MeDi) on Alzheimer disease (AD) biomarker changes (brain β-amyloid load via ¹¹C-Pittsburgh compound B [PiB] PET and neurodegeneration via ¹⁸F-fluorodeoxyglucose [FDG] PET and structural MRI) in midlife.

METHODS

Seventy 30- to 60-year-old cognitively normal participants with clinical, neuropsychological, and dietary examinations and imaging biomarkers at least 2 years apart were examined. These included 34 participants with higher (MeDi+) and 36 with lower (MeDi-) MeDi adherence. Statistical parametric mapping and volumes of interest were used to compare AD biomarkers between groups at cross section and longitudinally.

RESULTS

MeDi groups were comparable for clinical and neuropsychological measures. At baseline, compared to the MeDi+ group, the MeDi- group showed reduced FDG-PET glucose metabolism (CMRglc) and higher PiB-PET deposition in AD-affected regions (p < 0.001). Longitudinally, the MeDi--group showed CMRglc declines and PiB increases in these regions, which were greater than those in the MeDi+ group (p_interaction < 0.001). No effects were observed on MRI. Higher MeDi adherence was estimated to provide 1.5 to 3.5 years of protection against AD.

CONCLUSION

Lower MeDi adherence was associated with progressive AD biomarker abnormalities in middle-aged adults. These data support further investigation of dietary interventions for protection against brain aging and AD.

A Method for the Study of Cryoglobulin Solubilization Curves at 37°C. Preliminary Studies and Application to Plasma Exchange in Cryoglobulinemic Syndromes

A simple method for the study of kinetic solubility curves of cryoglobulins is presented. In its first application to the study of 21 patients with cryoglobulinemia, it was possible to ascertain that clinical condition roughly correlates with decreased solubility whereas no correlation is found with per cent cryocrit.

In the group of patients we studied, 6 underwent plasma exchange treatment when glomerulonephritis, acute renal insufficiency, cerebritis and polyneuropathy appeared: in these patients, following 2 to 5 apheretic sessions, solubility increased showing a sort of correlation with clinical benefits determined by treatment. The preliminarity of this study is underlined.

Mechanisms of Risk Reduction in the Clinical Practice of Alzheimer's Disease Prevention

Alzheimer’s disease (AD) is a neurodegenerative dementia that affects nearly 50 million people worldwide and is a major source of morbidity, mortality, and healthcare expenditure. While there have been many attempts to develop disease-modifying therapies for late-onset AD, none have so far shown efficacy in humans. However, the long latency between the initial neuronal changes and onset of symptoms, the ability to identify patients at risk based on family history and genetic markers, and the emergence of AD biomarkers for preclinical disease suggests that early risk-reducing interventions may be able to decrease the incidence of, delay or prevent AD. In this review, we discuss six mechanisms—dysregulation of glucose metabolism, inflammation, oxidative stress, trophic factor release, amyloid burden, and calcium toxicity—involved in AD pathogenesis that offer promising targets for risk-reducing interventions. In addition, we offer a blueprint for a multi-modality AD risk reduction program that can be clinically implemented with the current state of knowledge. Focused risk reduction aimed at particular pathological factors may transform AD to a preventable disorder in select cases.

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

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.

Lifestyle and vascular risk effects on MRI-based biomarkers of Alzheimer's disease: a cross-sectional study of middle-aged adults from the broader New York City area

OBJECTIVE

To investigate the effects of lifestyle and vascular-related risk factors for Alzheimer's disease (AD) on in vivo MRI-based brain atrophy in asymptomatic young to middle-aged adults.

DESIGN

Cross-sectional, observational.

SETTING

Broader New York City area. Two research centres affiliated with the Alzheimer's disease Core Center at New York University School of Medicine.

PARTICIPANTS

We studied 116 cognitively normal healthy research participants aged 30-60 years, who completed a three-dimensional T1-weighted volumetric MRI and had lifestyle (diet, physical activity and intellectual enrichment), vascular risk (overweight, hypertension, insulin resistance, elevated cholesterol and homocysteine) and cognition (memory, executive function, language) data. Estimates of cortical thickness for entorhinal (EC), posterior cingulate, orbitofrontal, inferior and middle temporal cortex were obtained by use of automated segmentation tools. We applied confirmatory factor analysis and structural equation modelling to evaluate the associations between lifestyle, vascular risk, brain and cognition.

RESULTS

Adherence to a Mediterranean-style diet (MeDi) and insulin sensitivity were both positively associated with MRI-based cortical thickness (diet: β_s≥0.26, insulin sensitivity β_s≥0.58, P≤0.008). After accounting for vascular risk, EC in turn explained variance in memory (P≤0.001). None of the other lifestyle and vascular risk variables were associated with brain thickness. In addition, the path associations between intellectual enrichment and better cognition were significant (β_s≥0.25 P≤0.001), as were those between overweight and lower cognition (β_s≥-0.22, P≤0.01).

CONCLUSIONS

In cognitively normal middle-aged adults, MeDi and insulin sensitivity explained cortical thickness in key brain regions for AD, and EC thickness predicted memory performance in turn. Intellectual activity and overweight were associated with cognitive performance through different pathways. Our findings support further investigation of lifestyle and vascular risk factor modification against brain ageing and AD. More studies with larger samples are needed to replicate these research findings in more diverse, community-based settings.

Cascade filtration: Clinical Application in 26 Patients with Immune Complex and Igm Mediated Diseases

A new technique which allows lymphocytapheresis to be combined with cascade filtration (CF) is described in this paper. This therapeutical approach was applied for the treatment of patients affected by necrotizing vasculitis (1), inflammatory myopathies (5), Cryoglobulinemia (5), immune complex polyneuropathies (7), rheumatoid arthritis (3) and psoriasis (3 patients). Two cases of Waldenstrom's macroglobulinemia were also treated after the onset of the hyperviscosity syndrome. 78 procedures have been performed without any untoward effect. From a clinical point of view all patients had some improvement following treatment, thereby confirming not only the clinical safety of this therapeutical approach but also its effectiveness at least in the management of diseases which usually respond to plasma exchange treatment. Laboratory investigations showed that with CF it is possible to selectively remove IgM, immune complexes, fibrinogen, lipoproteins and high molecular weight plasma components, sparing most albumin and IgG globulins (85 and 71%, respectively).

Female Sex and Alzheimer's Risk: The Menopause Connection

Along with advanced age and apolipoprotein E (APOE)-4 genotype, female sex is a major risk factor for developing late-onset Alzheimer's disease (AD). Considering that AD pathology begins decades prior to clinical symptoms, the higher risk in women cannot simply be accounted for by their greater longevity as compared to men. Recent investigation into sex-specific pathophysiological mechanisms behind AD risk has implicated the menopause transition (MT), a midlife neuroendocrine transition state unique to females. Commonly characterized as ending in reproductive senescence, many symptoms of MT are neurological, including disruption of estrogen-regulated systems such as thermoregulation, sleep, and circadian rhythms, as well as depression and impairment in multiple cognitive domains. Preclinical studies have shown that, during MT, the estrogen network uncouples from the brain bioenergetic system. The resulting hypometabolic state could serve as the substrate for neurological dysfunction. Indeed, translational brain imaging studies demonstrate that 40-60 year-old perimenopausal and postmenopausal women exhibit an AD-endophenotype characterized by decreased metabolic activity and increased brain amyloid-beta deposition as compared to premenopausal women and to age-matched men. This review discusses the MT as a window of opportunity for therapeutic interventions to compensate for brain bioenergetic crisis and combat the subsequent increased risk for AD in women.

Perimenopause and emergence of an Alzheimer's bioenergetic phenotype in brain and periphery

After advanced age, female sex is the major risk factor for Alzheimer’s disease (AD). The biological mechanisms underlying the increased AD risk in women remain largely undetermined. Preclinical studies identified the perimenopause to menopause transition, a neuroendocrine transition state unique to the female, as a sex-specific risk factor for AD. In animals, estrogenic regulation of cerebral glucose metabolism (CMRglc) falters during perimenopause. This is evident in glucose hypometabolism and decline in mitochondrial efficiency which is sustained thereafter. This study bridges basic to clinical science to characterize brain bioenergetics in a cohort of forty-three, 40–60 year-old clinically and cognitively normal women at different endocrine transition stages including premenopause (controls, CNT, n = 15), perimenopause (PERI, n = 14) and postmenopause (MENO, n = 14). All participants received clinical, laboratory and neuropsychological examinations, ¹⁸F-fluoro-deoxyglucose (FDG)-Positron Emission Tomography (PET) FDG-PET scans to estimate CMRglc, and platelet mitochondrial cytochrome oxidase (COX) activity measures. Statistical parametric mapping and multiple regression models were used to examine clinical, CMRglc and COX data across groups. As expected, the MENO group was older than PERI and controls. Groups were otherwise comparable for clinical measures and distribution of APOE4 genotype. Both MENO and PERI groups exhibited reduced CMRglc in AD-vulnerable regions which was correlated with decline in mitochondrial COX activity compared to CNT (p’s<0.001). A gradient in biomarker abnormalities was most pronounced in MENO, intermediate in PERI, and lowest in CNT (p<0.001). Biomarkers correlated with immediate and delayed memory scores (Pearson’s 0.26≤r≤0.32, p≤0.05). These findings validate earlier preclinical findings and indicate emergence of bioenergetic deficits in perimenopausal and postmenopausal women, suggesting that the optimal window of opportunity for therapeutic intervention in women is early in the endocrine aging process.

Sex differences in Alzheimer risk: Brain imaging of endocrine vs chronologic aging

OBJECTIVE

This observational multimodality brain imaging study investigates emergence of endophenotypes of late-onset Alzheimer disease (AD) risk during endocrine transition states in a cohort of clinically and cognitively normal women and age-matched men.

METHODS

Forty-two 40- to 60-year-old cognitively normal women (15 asymptomatic perimenopausal by age [CNT], 13 perimenopausal [PERI], and 14 postmenopausal [MENO]) and 18 age- and education-matched men were examined. All patients had volumetric MRI, ¹⁸F-fluoro-2-deoxyglucose (FDG)-PET (glucose metabolism), and Pittsburgh compound B-PET scans (β-amyloid [Aβ] deposition, a hallmark of AD pathology).

RESULTS

As expected, the MENO group was older than the PERI and CNT groups. Otherwise, groups were comparable on clinical and neuropsychological measures and APOE4 distribution. Compared to CNT women and to men, and controlling for age, PERI and MENO groups exhibited increased indicators of AD endophenotype, including hypometabolism, increased Aβ deposition, and reduced gray and white matter volumes in AD-vulnerable regions (p < 0.001). AD biomarker abnormalities were greatest in MENO, intermediate in PERI, and lowest in CNT women (p < 0.001). Aβ deposition was exacerbated in APOE4-positive MENO women relative to the other groups (p < 0.001).

CONCLUSIONS

Multimodality brain imaging indicates sex differences in development of the AD endophenotype, suggesting that the preclinical AD phase is early in the female aging process and coincides with the endocrine transition of perimenopause. These data indicate that the optimal window of opportunity for therapeutic intervention in women is early in the endocrine aging process.

Reduced Slow-Wave Sleep Is Associated with High Cerebrospinal Fluid Aβ42 Levels in Cognitively Normal Elderly

STUDY OBJECTIVES

Emerging evidence suggests a role for sleep in contributing to the progression of Alzheimer disease (AD). Slow wave sleep (SWS) is the stage during which synaptic activity is minimal and clearance of neuronal metabolites is high, making it an ideal state to regulate levels of amyloid beta (Aβ). We thus aimed to examine relationships between concentrations of Aβ42 in the cerebrospinal fluid (CSF) and measures of SWS in cognitively normal elderly subjects.

METHODS

Thirty-six subjects underwent a clinical and cognitive assessment, a structural MRI, a morning to early afternoon lumbar puncture, and nocturnal polysomnography. Correlations and linear regression analyses were used to assess for associations between CSF Aβ42 levels and measures of SWS controlling for potential confounders. Resulting models were compared to each other using ordinary least squared linear regression analysis. Additionally, the participant sample was dichotomized into "high" and "low" Aβ42 groups to compare SWS bout length using survival analyses.

RESULTS

A significant inverse correlation was found between CSF Aβ42 levels, SWS duration and other SWS characteristics. Collectively, total SWA in the frontal lead was the best predictor of reduced CSF Aβ42 levels when controlling for age and ApoE status. Total sleep time, time spent in NREM1, NREM2, or REM sleep were not correlated with CSF Aβ42.

CONCLUSIONS

In cognitively normal elderly, reduced and fragmented SWS is associated with increases in CSF Aβ42, suggesting that disturbed sleep might drive an increase in soluble brain Aβ levels prior to amyloid deposition.

Transient and chronic seizure-induced inflammation in human focal epilepsy

In animal models, inflammation is both a cause and consequence of seizures. Less is known about the role of inflammation in human epilepsy. We performed positron emission tomography (PET) using a radiotracer sensitive to brain inflammation in a patient with frontal epilepsy ~36 h after a seizure as well as during a seizure-free period. When statistically compared to a group of 12 matched controls, both of the patient's scans identified a frontal (supplementary motor area) region of increased inflammation corresponding to his clinically defined seizure focus, but the postseizure scan showed significantly greater inflammation intensity and spatial extent. These results provide new information about transient and chronic neuroinflammation in human epilepsy and may be relevant to understanding the process of epileptogenesis and guiding therapy.

Orexin-A is Associated with Increases in Cerebrospinal Fluid Phosphorylated-Tau in Cognitively Normal Elderly Subjects

STUDY OBJECTIVES

To evaluate the role of orexin-A with respect to cerebrospinal fluid (CSF) Alzheimer disease (AD) biomarkers, and explore its relationship to cognition and sleep characteristics in a group of cognitively normal elderly individuals.

METHODS

Subjects were recruited from multiple community sources for National Institutes of Health supported studies on normal aging, sleep and CSF biomarkers. Sixty-three participants underwent home monitoring for sleep-disordered breathing, clinical, sleep and cognitive evaluations, as well as a lumbar puncture to obtain CSF. Individuals with medical history or with magnetic resonance imaging evidence of disorders that may affect brain structure or function were excluded. Correlation and linear regression analyses were used to assess the relationship between orexin-A and CSF AD-biomarkers controlling for potential sociodemographic and sleep confounders.

RESULTS

Levels of orexin-A, amyloid beta 42 (Aβ42), phosphorylated-tau (P-Tau), total-tau (T-Tau), Apolipoprotein E4 status, age, years of education, reported total sleep time, number of awakenings, apnea-hypopnea indices (AHI), excessive daytime sleepiness, and a cognitive battery were analyzed. Subjects were 69.59 ± 8.55 years of age, 57.1% were female, and 30.2% were apolipoprotein E4+. Orexin-A was positively correlated with Aβ42, P-Tau, and T-Tau. The associations between orexin-A and the AD-biomarkers were driven mainly by the relationship between orexin-A and P-Tau and were not influenced by other clinical or sleep characteristics that were available.

CONCLUSIONS

Orexin-A is associated with increased P-Tau in normal elderly individuals. Increases in orexin-A and P-Tau might be a consequence of the reduction in the proportion of the deeper, more restorative slow wave sleep and rapid eye movement sleep reported with aging.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov registration number NCT01962779.

Effects of vascular risk factors, statins, and antihypertensive drugs on PiB deposition in cognitively normal subjects

INTRODUCTION

Hypertension, hypercholesterolemia, and obesity increase the risk of dementia. Although their detection is commonly followed by an introduction of treatment, little is known about how medications frequently used to treat vascular risk affect amyloid deposition.

METHODS

A cross-sectional study of 156 subjects who underwent positron emission tomography with PiB. Using linear regression, we tested whether blood pressure, cholesterol, overweight/obese status, angiotensin receptor blockers (ARBs), beta-blockers, diuretics, angiotensin converting enzyme inhibitors, and statins predicted amyloid deposition.

RESULTS

The use of ARBs (β = -.15, P = .044) and diuretics (β = -.20, P = .006) predicted less amyloid accumulation; older age (β = .29, P < .001) and statins (β = .23, P = .004) were related to greater amyloid deposition. Overweight and/or obese women had more cortical amyloid than their peers.

DISCUSSION

Prospective studies should confirm effects of drugs and increased body weight on amyloid accumulation and establish whether they translate into measurable clinical outcomes. Women may be more susceptible to harmful effects of obesity.

Dissociation of Down syndrome and Alzheimer's disease effects with imaging

Introduction

Down Syndrome (DS) adults experience accumulation of Alzheimer's disease (AD)–like amyloid plaques and tangles and a high incidence of dementia and could provide an enriched population to study AD-targeted treatments. However, to evaluate effects of therapeutic intervention, it is necessary to dissociate the contributions of DS and AD from overall phenotype. Imaging biomarkers offer the potential to characterize and stratify patients who will worsen clinically but have yielded mixed findings in DS subjects.

Methods

We evaluated 18F fluorodeoxyglucose positron emission tomography (PET), florbetapir PET, and structural magnetic resonance (sMR) image data from 12 nondemented DS adults using advanced multivariate machine learning methods.

Results

Our results showed distinctive patterns of glucose metabolism and brain volume enabling dissociation of DS and AD effects. AD-like pattern expression corresponded to amyloid burden and clinical measures.

Discussion

These findings lay groundwork to enable AD clinical trials with characterization and disease-specific tracking of DS adults.

Let Food Be Thy Medicine: Diet, Nutrition, and Biomarkers' Risk of Alzheimer's Disease

Epidemiological evidence linking diet-one of the most important modifiable lifestyle factors-and risk of Alzheimer's disease (AD)-the most common cause of dementia-is rapidly increasing. However, the biological mechanisms underlying the relationship between dietary nutrients, brain aging, and risk of AD are largely unexplored. Recent studies using brain imaging and biological markers of AD have begun to clarify how diet and nutrition modulate risk of AD in cognitively normal individuals, especially those at increased genetic risk. Such knowledge is critical prior to implementing dietary recommendations for prevention and treatment of disease.