Long-term systemic inflammation and cognitive impairment in a population-based cohort

Lifestyle and factors of vascular and metabolic health and inflammation are associated with sensorineural-neurocognitive aging in older adults

This study's aim was to identify risk factors associated with sensorineural and neurocognitive function (brain aging) in older adults. In N = 1,478 Epidemiology of Hearing Loss Study participants (aged 64-100 years, 59% women), we conducted sensorineural and cognitive tests, which were combined into a summary measure using Principal Component Analysis (PCA). Participants with a PCA score <-1 standard deviation (SD) were considered to have brain aging. Incident brain aging was defined as PCA score <-1 SD at 5-year follow-up among participants who had a PCA score ≥-1 SD at baseline. Logistic regression and Poisson models were used to estimate associations between baseline risk factors of lifestyle, vascular and metabolic health, and inflammation and prevalent or incident brain aging, respectively. In an age-sex adjusted multivariable model, not consuming alcohol (odds ratio(OR) = 1.77, 95% confidence Interval (CI) = 1.18,2.66), higher interleukin-6 levels (OR = 1.30, 95% CI = 1.03,1.64), and depressive symptoms (OR = 2.44, 95% CI = 1.63,3.67) were associated with a higher odds of having brain aging, while higher education had protective effects (OR = 0.55, 95% CI = 0.33,0.94). A history of stroke, arterial stiffness, and obesity were associated with an increased risk of developing brain aging during the five years of follow-up. Lifestyle, vascular, metabolic and inflammatory factors were associated with brain aging in older adults, which adds to the evidence of shared pathways for sensorineural and neurocognitive declines in aging. Targeting these shared central processing etiological factors with interventions may lead to retention of better neurological function, benefiting multiple systems, i.e., hearing, smell, and cognition, ultimately helping older adults retain independence and higher quality of life longer.

Handgrip strength asymmetry and cognitive impairment risk: Insights from a seven-year prospective cohort study

OBJECTIVES

This study aimed to explore the links of handgrip strength and asymmetry with cognitive impairment.

DESIGN

This was a seven-year prospective cohort study.

SETTING AND PARTICIPANTS

We used data from wave 3 (2015-2017) to wave 5 (2019-2022) from the ongoing Taiwan Initiative of Geriatric Epidemiological Research (TIGER), with wave 3 as the baseline (n = 446). The study included community-dwelling participants aged 65 years or older.

MEASUREMENTS

Handgrip strength was measured, and abnormalities were determined based on handgrip strength weakness and asymmetry. Handgrip strength asymmetry was categorized into three groups at baseline based on the handgrip strength ratio (left handgrip strength/right handgrip strength). Cognitive tests evaluating global and specific cognitive domains were conducted at baseline and two biennial follow-ups. Generalized linear mixed models were utilized to assess the associations of abnormal handgrip strength with global cognition and multiple cognitive domain progression over time.

RESULTS

This study included 392 dementia-free participants, with an average age of 75.8 years and 179 (45.7%) males. Mild handgrip strength asymmetry was present in 88 participants (22.4%), while 53 (13.5%) exhibited moderate asymmetry. In men, the coexistence of low handgrip strength and handgrip strength asymmetry was linked to cognitive impairment over time. These associations were observed in global cognition (β^ = -1.76, 95% CI: -2.79 to -0.74), memory (immediate free recall: β^ = -0.67, 95% CI: -1.17 to -0.17), executive function (Trail Making Test-A: β^ = -0.54, 95% CI: -0.94 to -0.13), and attention (Digit span-forward: β^ = -1.00, 95% CI: -1.46 to -0.54).

CONCLUSIONS

This study found that individuals with reduced handgrip strength and handgrip strength asymmetry had an increased risk of cognitive impairment across various domains. Moreover, this association appears to be more pronounced among men than women. Incorporating these simple assessments into regular clinical practice improves the allocation of limited screening resources and timely clinical interventions in older adults.

Association between the neutrophil-to-lymphocyte ratio and cognitive impairment: a meta-analysis of observational studies

Background

Systemic inflammation is one of the underlying mechanisms of cognitive impairment. The neutrophil-to-lymphocyte ratio (NLR) has emerged as a systemic inflammation indicator. This meta-analysis aimed to evaluate the association between high NLR and cognitive impairment (CI) risk.

Method

A comprehensive systematic search was conducted to identify eligible studies published until May 30, 2023. The reference group comprised patients with the lowest NLR level, whereas the exposure group comprised those with the highest NLR level. The main outcome was to examine the relationship between NLR and CI risk. The secondary outcome included the association between patient characteristics or comorbidities and CI risk.

Results

This meta-analysis included 11 studies published between 2018 and 2023, involving 10,357 patients. Patients with CI had a higher NLR than those without (mean difference=0.35, 95% confidence interval [CI]: 0.26-0.44, p < 00001, I2 = 86%). Consistently, pooled results revealed an association between high NLR and CI risk (odds ratio [OR]=2.53, 95% CI:1.67-3.82, p<0.0001, I2 = 84%). Furthermore, aging (mean difference =4.31 years, 95% CI:2.83-5.8, p < 0.00001, I2 = 92%), diabetes (OR=1.59, 95% CI:1.35-1.88, p < 0.00001, I2 = 66%), and hypertension (OR=1.36, 95% CI:1.19-1.57, p < 0.00001, I2 = 0%) were significant risk factors for CI. However, no significant associations were observed between CI and male gender (OR = 0.84, 95% CI:0.64-1.11, p = 0.22, I2 = 81%), body mass index (mean = -0.32 kg/m2, 95% CI: -0.82, 0.18, p = 0.2, I2 = 82%), alcohol consumption (OR = 1.11, 95% CI:0.95-1.3, p = 1.35, I2 = 0%), and smoking (OR = 0.99, 95% CI:0.87-1.13, p = 0.86, I2 = 0%). Meta-regression found that diabetes and hypertension, but not age, significantly moderated the association between NLR and CI.

Conclusion

This meta-analysis showed a significant association between high NLR and increased CI risk. Moreover, meta-regression identified diabetes and hypertension, but not age, as significant moderating factors in the relationship between NLR and CI. To validate and strengthen these findings, further large-scale studies are required.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023430384, identifier CRD42023430384.

Association of Osteoarthritis and Functional Limitations With Cognitive Impairment Among Older Adults in the United States

Objective: Given overlapping pathophysiology, this study sought to assess the association between osteoarthritis (OA), functional impairment, and cognitive impairment in the aging population. Methods: The National Health and Nutrition Examination Survey was used to identify participants >60 years of age. We analyzed multivariable associations of grouped participants that underwent cognitive function testing using linear and logistic regression, adjusting for sex, age, race, and ethnicity. Results: Of 2776 identified participants representing a population of 50,242,917, 40% did not report OA or functional limitations; 21% had OA but not functional limitations; 15% did not have OA but had functional limitations; 17% had OA and related functional limitations; and 7% had OA and non-arthritic functional limitations. OA was not independently associated with cognitive impairment. Contrarily, functional limitations were associated with cognitive impairment regardless of OA diagnosis. Discussion: Cognitive impairment is not associated with OA, but rather functional limitations, potentially guiding future intervention.

Anthracycline chemotherapy, vascular dysfunction and cognitive impairment: burgeoning topics and future directions

Anthracyclines, chemotherapeutic agents used to treat common forms of cancer, increase cardiovascular (CV) complications, thereby necessitating research regarding interventions to improve the health of cancer survivors. Vascular dysfunction, which is induced by anthracycline chemotherapy, is an established antecedent to overt CV diseases. Potential treatment options for ameliorating vascular dysfunction have largely been understudied. Furthermore, patients treated with anthracyclines have impaired cognitive function and vascular dysfunction is an independent risk factor for the development of mild cognitive impairment. Here, we will focus on: anthracycline chemotherapy associated CV diseases risk; how targeting mechanisms underlying vascular dysfunction may be a means to improve both CV and cognitive health; and research gaps and potential future directions for the field of cardio-oncology.

From the Bush to the Brain: Preclinical Stages of Ethnobotanical Anti-Inflammatory and Neuroprotective Drug Discovery-An Australian Example

The Australian rainforest is a rich source of medicinal plants that have evolved in the face of dramatic environmental challenges over a million years due to its prolonged geographical isolation from other continents. The rainforest consists of an inherent richness of plant secondary metabolites that are the most intense in the rainforest. The search for more potent and more bioavailable compounds from other plant sources is ongoing, and our short review will outline the pathways from the discovery of bioactive plants to the structural identification of active compounds, testing for potency, and then neuroprotection in a triculture system, and finally, the validation in an appropriate neuro-inflammatory mouse model, using some examples from our current research. We will focus on neuroinflammation as a potential treatment target for neurodegenerative diseases including multiple sclerosis (MS), Parkinson's (PD), and Alzheimer's disease (AD) for these plant-derived, anti-inflammatory molecules and highlight cytokine suppressive anti-inflammatory drugs (CSAIDs) as a better alternative to conventional nonsteroidal anti-inflammatory drugs (NSAIDs) to treat neuroinflammatory disorders.

Cellular mechanisms in brain aging: Focus on physiological and pathological aging

Aging is a natural phenomenon characterized by accumulation of cellular damage and debris. Oxidative stress, cellular senescence, sustained inflammation, and DNA damage are the main cellular processes characteristic of aging associated with morphological and functional decline. These effects tend to be more pronounced in tissues with high metabolic rates such as the brain, mainly in regions such as the prefrontal cortex, hippocampus, and amygdala. These regions are highly related to cognitive behavior, and therefore their atrophy usually leads to decline in processes such as memory and learning. These cognitive declines can occur in physiological aging and are exacerbated in pathological aging. In this article, we review the cellular processes that underlie the triggers of aging and how they relate to one another, causing the atrophy of nerve tissue that is typical of aging. The main topic of this review to determine the central factor that triggers all the cellular processes that lead to cellular aging and discriminate between normal and pathological aging. Finally, we review how the use of supplements with antioxidant and anti-inflammatory properties reduces the cognitive decline typical of aging, which reinforces the hypothesis of oxidative stress and cellular damage as contributors of physiological atrophy of aging. Moreover, cumulative evidence suggests their possible use as therapies, which improve the aging population's quality of life.

The association between total cholesterol and cognitive impairment in chronic obstructive pulmonary disease patients

AIM

Chronic obstructive pulmonary disease (COPD) is primarily a respiratory system disorder associated with extrapulmonary conditions. Cognitive impairment (CoI) is very common among COPD patients This study sought to investigate the association between CoI and clinical parameters, inflammatory markers and lipid profiles in a COPD patient population.

METHODS

The study population included 111 stable COPD patients. COPD was diagnosed according to Global Initiative for Chronic Obstructive Lung Disease guideline. Total complete blood count test and biochemical measurements including lipid profile were performed. Afterwards, all patients underwent neuropsychological assessment including Hospital Anxiety and Depression Scale (HADS), Pittsburgh Sleep Quality Index and Montreal Cognitive Assessment (MoCA) tests.

RESULTS

The patients were categorized into two groups according to their MoCA test score: MoCA score ≤ 21 (CoI) (n = 69) and MoCA score > 21 (normal cognition) (n = 42). Total cholesterol (TC) levels were significantly lower in patients with CoI compared to patients with normal cognition. Inflammation related parameters including C-reactive protein were similar among groups. Multivariate logistic regression analysis yielded education, HADS score and TC (OR:1.02, 95% CI:1.00-1.04, p = 0.025) as independent predictors of MoCA score.

CONCLUSION

TC independently associates with CoI in COPD patients. There is comparable inflammatory status in COPD patients with CoI compared to COPD patients with normal cognition.

Predictors of cognitive decline in older individuals without dementia: An updated meta-analysis

OBJECTIVE

To evaluate the effect of overall peripheral inflammatory levels on cognitive function, we explored the relationship between established biomarkers of peripheral inflammation (circulating C-reactive protein [CRP], interleukin-6 [IL-6], and tumor necrosis factor-α [TNF-α]) and cognitive decline by performing a review of observational studies and creating an updated summary.

METHODS

We included literatures exploring the relationship between peripheral levels of CRP, IL-6, and TNF-α and subsequent cognitive decline, published until July 2022, by searching the following databases: PubMed, Embase, Web of Science, the Cochrane Library, ClinicalTrials, CNKI, and VIP databases. We used random-effects models to pool the odds ratios (ORs) for the risks of subsequent cognitive decline in older adults with high levels of peripheral inflammation. We initially screened out 501 literatures, of which only 17 were ultimately eligible. Overall, there were 19,516 older individuals included in our meta-analysis, and 2134 of them experienced subsequent cognitive change.

RESULTS

Individuals with high levels of peripheral inflammation may have 14% more chance to develop subsequent cognitive decline than those with low levels (OR = 1.14, 95% CI: 1.03-1.27; p < 0.00001). In the subgroup analysis, the incidence of cognitive decline was higher in individuals with high levels of IL-6. This study further demonstrates the link between systemic inflammation and cognitive status.

INTERPRETATION

Detecting CRP, IL-6, and TNF-α in peripheral blood is necessary, as they may become effective indicators for forthcoming cognitive performance.

Defining the role of Interleukin-6 for the development of perioperative neurocognitive disorders: Evidence from clinical and preclinical studies

For most, staying "mentally sharp" as they age is a very high priority that may be thwarted by the consequences of a postoperative complication unrelated to the disorder which necessitated the surgical intervention. Perioperative neurocognitive disorder (PND) is an overarching term for cognitive impairment in surgical patients, that includes conditions from delirium to dementia, affecting more than 7 million patients annually in the US, and which threatens both functional independence and life. Clinical trials and meta-analyses have identified the association between PNDs and increased perioperative levels of Interleukin-6 (IL-6), a pleiotropic cytokine that is both necessary and sufficient for postoperative memory decline in a preclinical model of PND. Recently, we reported that, in adult male wild-type mice subjected to tibial fracture under general anesthesia, IL-6 trans-signaling in hippocampal CA1 neurons mediates surgery-induced memory impairment. As there are no therapeutic options for preventing or reversing PNDs, patients and their caregivers, as well as the healthcare industry, endure staggering costs. Olamkicept, a highly selective IL-6 trans-signaling blocker has shown to be efficacious and safe in clinical trials involving patients with inflammatory bowel disease, another condition for which IL-6 trans-signaling is the mediating mechanism. Subject to a demonstration that olamkicept is effective in preventing cognitive impairment in vulnerable (aged and Alzheimer's Disease) preclinical PND models, clinical trials involving aged and/or cognitively impaired surgical patients should be undertaken to study olamkicept's utility for PNDs.

Inflammation, metabolic dysregulation and environmental neurotoxins and risk of cognitive decline and impairment in midlife

BACKGROUND

Age-related declines in cognitive function may begin in midlife.

PURPOSE

To determine whether blood-based biomarkers of inflammation, metabolic dysregulation and neurotoxins are associated with risk of cognitive decline and impairment.

METHODS

Baseline blood samples from the longitudinal Beaver Dam Offspring Study (2005-2008) were assayed for markers of inflammation, metabolic dysregulation, and environmental neurotoxins. Cognitive function was measured at baseline, 5-year (2010-2013) and 10-year (2015-2017) examinations. Participants without cognitive impairment at baseline and with cognitive data from at least one follow-up were included. Cox proportional hazards models were used to evaluate associations between baseline blood biomarkers and the 10-year cumulative incidence of cognitive impairment. Poisson models were used to estimate the relative risk (RR) of 5-year decline in cognitive function by baseline blood biomarkers. Models were adjusted for age, sex, education, and cardiovascular related risk factors.

RESULTS

Participants (N = 2421) were a mean age of 49 years and 55% were women. Soluble vascular cell adhesion molecule-1 (sVCAM-1Tertile(T)3 vs T1-2 hazard ratio (HR) = 1.72, 95% confidence interval (CI) = 1.05,2.82) and hemoglobin A1C (HR = 1.75, 95% CI = 1.18,2.59, per 1% in women) were associated with the 10-year cumulative incidence of cognitive impairment. sVCAM-1 (RRT3 vs T1-2 = 1.45, 95% CI = 1.06,1.99) and white blood cell count (RR = 1.10, 95% CI = 1.02,1.19, per 103/μL) were associated with 5-year cognitive decline.

CONCLUSIONS

Biomarkers related to inflammation and metabolic dysregulation were associated with an increased risk of developing cognitive decline and impairment. These results extend previous research in cognitive aging to early markers of cognitive decline in midlife, a time when intervention methods may be more efficacious.

Peripheral high levels of CRP predict progression from normal cognition to dementia: A systematic review and meta-analysis

OBJECTIVE

Several cross-sectional studies have demonstrated a relationship between inflammation and dementia. Uncertainty exists over the ability of C-reactive protein (CRP), one of the most investigated markers of inflammation, to predict the progression of normal cognition to dementia. A systematic review and meta-analysis were performed to assess whether high peripheral levels of CRP are associated with cognitive impairment and whether CRP is a risk factor for predicting progression from normal cognition to cognitive decline or dementia.

METHODS

Literature published before November 2022 was retrieved from PubMed, Embase, and Web of Science. Prospective cohort studies that employed recognized evaluation instruments to assess global cognitive function or used accepted diagnostic criteria to ascertain dementia were selected. Subgroup analysis was conducted on specific cognitive domains and causes of dementia (i.e., Alzheimer's disease and vascular dementia). Odds ratios (ORs) and hazard ratios (HRs) were extracted and merged to facilitate data analysis. A random-effects model was used for the meta-analysis and a descriptive analysis of the data that could not be merged was conducted.

RESULTS

A total of 13 articles (14 cohort studies) were included for meta-analysis and six articles were included for descriptive analysis. The results showed that high CRP levels were not related to future cognitive decline (OR = 1.115; 95 % CI: 0.830-1.497; p = 0.469) but were associated with an increased risk of conversion to dementia. (HR = 1.473; 95 % CI: 1.037-2.090; p = 0.0394). This association persisted after full adjustment for potential covariates, with an OR of 1.044 (95 % CI:0.767-1.421, p = 0.785) for cognitive decline and an HR of 1.429 (95 % CI:1.088-1.876, p = 0.010) for dementia. The subgroup analysis showed that a higher level of CRP was related to a decline in visual-spatial ability (OR = 1.402, 95 % CI: 1.045-1.882, p = 0.024) and the risk of conversion to vascular dementia (total effect size of OR and HR = 2.769, 95 % CI: 1.586-4.83, p = 0.000).

CONCLUSIONS

Higher CRP levels as an indicator of chronic systemic inflammation cannot predict future cognitive decline but may indicate a higher risk of conversion to dementia.

Associations of Midlife Lifestyle and Health Factors with Long-Term Changes in Blood-Based Biomarkers of Alzheimer's Disease and Neurodegeneration

BACKGROUND

Pathological biomarkers of Alzheimer's disease (AD) and other dementias can change decades before clinical symptoms. Lifestyle and health factors might be relevant modifiable risk factors for dementia. Many previous studies have been focusing on associations of lifestyle and health-related factors with clinical outcomes later in life.

OBJECTIVE

We aimed to determine to what extent midlife factors of lifestyle, inflammation, vascular, and metabolic health were associated with long-term changes in blood-based biomarkers of AD (amyloid beta (Aβ)) and neurodegeneration (neurofilament light chain (NfL); total tau(TTau)).

METHODS

In 1,529 Beaver Dam Offspring Study (BOSS) participants (mean age 49 years, standard deviation (SD) = 9; 54% were women), we applied mixed-effects models with baseline risk factors as determinants and 10-year serum biomarker change as outcomes.

RESULTS

We found that education and inflammatory markers were associated with levels and/or change over time across all three markers of AD and neurodegeneration in the blood. There were baseline associations of measures of cardiovascular health with lower Aβ42/Aβ40. TTau changed little over time and was higher in individuals with diabetes. Individuals with lower risk in a number of cardiovascular and metabolic risk factors, including diabetes, hypertension, and atherosclerosis had slower accumulation of neurodegeneration over time, as determined by NfL levels.

CONCLUSION

Various lifestyle and health factors, including education and inflammation, were associated with longitudinal changes of neurodegenerative and AD biomarker levels in midlife. If confirmed, these findings could have important implications for developing early lifestyle and health interventions that could potentially slow processes of neurodegeneration and AD.

Links between inflammation and immune functioning with cognitive status among older Americans in the Health and Retirement Study

Elevated inflammation and poor immune functioning are tied to worse cognitive health. Both processes are fundamental to aging and are strongly implicated in the development of age-related health outcomes, including cognitive status. However, results from prior studies evaluating links between indicators of inflammation and immune function and cognitive impairment have been inconsistent due to biomarker selection, sample selection, and cognitive outcome. Using the Health and Retirement Study (HRS), a nationally representative study of older adults in the United States, we assessed how indicators of inflammation (neutrophil-lymphocyte ratio (NLR), albumin, CRP, IL6, IL10, IL-1Ra, sTNFR1, and TGFβ1) and immune functioning (CMV, CD4+ TN/TM, and CD8+ TN/TM) are associated with cognitive status. First, to examine the association between each biomarker and cognitive status, we tested whether markers of inflammation and immune functioning varied across cognitive status categories. We found that dementia and cognitive impairment without dementia (CIND) were associated with elevated inflammation and poorer immune functioning across biomarkers except for CD4+ TN/TM. Next, we estimated multinomial logistic regression models to assess which biomarkers would continue to be associated with dementia and CIND, net of each other. In these models, albumin, cytokines, CMV, CD4+ TN/TM, and CD8+ TN/TM are associated with cognitive status. Because poor immune functioning and increased inflammation are associated with cognitive impairment, improving immune functioning and reducing inflammation may provide a mechanism for reducing ADRD risk in the population.

Associations of sensory and motor function with blood-based biomarkers of neurodegeneration and Alzheimer's disease in midlife

Pathological biomarkers of dementia and Alzheimer's disease (AD) change decades before clinical symptoms. Common sensory and motor changes in aging adults may be early markers of neurodegeneration. We investigated if midlife sensory and motor functions in Beaver Dam Offspring Study (BOSS) participants (N = 1529) were associated with longitudinal changes in blood-based biomarkers of neurodegeneration (neurofilament light chain (NfL); total tau (TTau)) and AD (amyloid beta (Aβ)). Mixed-effects models with baseline sensory and motor function as determinants and 10-year biomarker change as outcome were used. Participants with hearing impairment and worse motor function (among women) showed faster increases in NfL level over time (0.8% per year; 0.3% per year, respectively). There were no significant associations with TTau or Aβ. We found consistent relationships between worse baseline hearing and motor function with a faster increase in neurodegeneration, specifically serum NfL level. Future studies with longer follow-up should determine if sensory and motor changes are more reflective of general neurodegeneration than AD-specific pathology and whether sensory and motor tests may be useful screening tools for neurodegeneration risk.

Peripheral inflammation marker relationships to cognition in healthy older adults - A systematic review

Several cognitive domains show decline with increasing age, which is associated with poorer work performance and reduced quality of life. As many nations show a rise in the number of citizens aged over 60 years, the study of the mechanisms underlying age-related cognitive functional reductions, such as inflammation, is important. Inflammaging has been implicated in progressive minor decline through to dementia typologies, with peripheral cytokine patterns investigated for their potential role in cognitive function. Assessing the relationship between these markers and cognitive performance could elucidate mechanisms with aging beyond neuropathologies. The research literature suggests peripheral cytokines/chemokines such as interleukin-6 and c-reactive protein are associated with cognitive processing. In this systematic review, we examine the evidence for a relationship between a range of peripheral inflammatory markers and domains of cognitive function in healthy older adults. To do this, a literature search was conducted using the following databases: SCOPUS, PubMed, Web of Science, and PsycINFO. Risk of bias was assessed using the Cochrane Risk of Bias Tool. Twenty-nine studies met our inclusion criteria. Although a wide range of systemic inflammatory biomarkers were examined, IL-6 and CRP were the most studied. The evidence suggests an inverse inflammatory biomarker-cognitive function relationship whereby elevations in most cytokines were associated with poorer performance across cognitive domains. The findings contribute to our understanding of peripheral inflammation and domains of cognitive function, offering insight into inflammaging processes.

Serum clinical laboratory tests and risk of incident dementia: a prospective cohort study of 407,190 individuals

Prevention of dementia is a public health priority, and the identification of potential biomarkers may provide benefits for early detection and prevention. This study investigates the association of common serum laboratory tests with the risk of incident dementia. Among 407,190 participants from the UK Biobank (median follow-up of 9.19 years), we investigated the linear and nonlinear effects of 30 laboratory measures on the risk of all-cause dementia using Cox models and restricted cubic spline models. We found that dementia incidence was associated with low vitamin D concentration (hazard ratio 0.994, 95% confidence interval 0.993-0.996), indicators of endocrine disorders: IGF-1 level (P for non-linearity = 1.1E-05), testosterone level (P for non-linearity = 0.006); high sex-hormone-binding globulin level (HR 1.004, 95% CI: 1.003-1.006); reduced liver function: lower alanine aminotransferase (HR 0.990, 95% CI: 0.986-0.995); renal dysfunction: cystatin C level (P for non-linearity = 0.028); oxidative stress: lower urate level (HR 0.998, 95% CI: 0.998-0.999); lipids dysregulation: lower LDL (HR 0.918, 95% CI: 0.872-0.965) and triglycerides (HR 0.924, 95% CI: 0.882-0.967) concentrations; insulin resistance: high glucose (HR 1.093, 95% CI: 1.045-1.143) and HbA1c (HR 1.017, 95% CI: 1.009-1.025) levels; immune dysbiosis: C-reactive protein (P for non-linearity = 5.5E-09). In conclusion, markers of vitamin D deficiency, GH-IGF-1 axis disorders, bioactive sex hormone deficiency, reduced liver function, renal abnormalities, oxidation, insulin resistance, immune dysbiosis, and lipids dysregulation were associated with incident dementia. Our results support a contributory role of systemic disorders and diverse biological processes to onset of dementia.

Chronic acrylamide exposure resulted in dopaminergic neuron loss, neuroinflammation and motor impairment in rats

Acrylamide (ACR) as a by-product of Maillard reaction is widely present in food. Although ACR is known to exhibit neurotoxicity, most studies about ACR neurotoxicity are currently short-term high-dose providing limited reference value for human exposure. The present study aims to determine the effects of chronic ACR exposure on dopaminergic neurons in rat nigra and the potential mechanism from the perspective of NLRP3 inflammasome-mediated neuroinflammation. The SD rats were maintained on treated drinking water providing dosages of 0, 0.5, or 5 mg/kg/day ACR for 12 months. ACR exposure caused motor dysfunction in rats, which was associated with dopaminergic neuron loss, α-Synuclein (α-Syn) accumulation and decreased brain-derived neurotrophic factor (BDNF) in nigra. ACR activated microglia by increasing Iba-1⁺, Iba-1⁺CD68⁺ positive cells and the percentage of ameboid-shaped ones in rat nigra. ACR markedly upregulated the protein levels of NLRP3 inflammasome constituents NLRP3 and caspase-1 and inflammatory cytokine IL-1β. ACR chronic exposure increased the risk of Parkinson's disease (PD) like dopaminergic neuron depletion in nigra potentially through NLRP3 inflammasome-mediated neuroinflammtion.

Acute versus chronic inflammatory markers and cognition in older black adults: Results from the Minority Aging Research Study

Peripheral inflammation is elevated in older Black adults, an elevation which prior work has suggested may be due to chronic stress associated with systemic racism and related adverse cardiovascular health conditions. Inflammation is also involved in the pathogenic processes of dementia; however, limited (and mixed) results exist concerning inflammation and cognitive decline in Black adults. We characterized patterns of inflammation and their role in cognitive decline in 280 older Black adults (age = 72.99 ± 6.00 years; 69.6% female) from the Minority Aging Research Study (MARS) who were without dementia at baseline and followed between 2 and 15 years (mean = 9 years). Participants completed a blood draw at baseline and annual cognitive evaluations. Serum was assayed for 9 peripheral inflammatory markers; 19 neuropsychological test scores were used to create indices of global cognition and five cognitive domains. Principal component analysis with varimax rotation characterized patterns of inflammation with factor loadings > 0.6 per component contributing to two composite scores representing acute/upstream and chronic/downstream inflammation. These composites were used as separate predictors in linear mixed regression models to determine associations with level and change in cognition adjusting for relevant covariates. Higher baseline upstream/acute inflammation associated with lower baseline semantic memory (p = .040) and perceptual speed (p = .046); it was not related to cognitive decline. By contrast, higher baseline downstream/chronic inflammation associated with faster declines in global cognition (p = .010), episodic (p = .027) and working memory (p = .006); it was not related to baseline cognition. For older Black adults, chronic, but not acute, inflammation may be a risk factor for changes in cognition.

Pharmacological considerations for treating neuroinflammation with curcumin in Alzheimer's disease

Prof. Dr. Peter Riederer, the former Head of the Neurochemistry Department of the Psychiatry and Psychotherapy Clinic at the University of Würzburg (Germany), has been one of the pioneers of research into oxidative stress in Parkinson's and Alzheimer's disease (AD). This review will outline how his scientific contribution to the field has opened a new direction for AD treatment beyond "plaques and tangles". In the 1990s, Prof. Riederer was one of the first scientists who proposed oxidative stress and neuroinflammation as one of the major contributors to Alzheimer's disease, despite the overwhelming support for the "amyloid-only" hypothesis at the time, which postulated that the sole and only cause of AD is β-amyloid. His group also highlighted the role of advanced glycation end products, sugar and dicarbonyl-derived protein modifications, which crosslink proteins into insoluble aggregates and potent pro-inflammatory activators of microglia. For the treatment of chronic neuroinflammation, he and his group suggested that the most appropriate drug class would be cytokine-suppressive anti-inflammatory drugs (CSAIDs) which have a broader anti-inflammatory action range than conventional non-steroidal anti-inflammatory drugs. One of the most potent CSAIDs is curcumin, but it suffers from a variety of pharmacokinetic disadvantages including low bioavailability, which might have tainted many human clinical trials. Although a variety of oral formulations with increased bioavailability have been developed, curcumin's absorption after oral delivery is too low to reach therapeutic concentrations in the micromolar range in the systemic circulation and the brain. This review will conclude with evidence that rectally applied suppositories might be the best alternatives to oral medications, as this route will be able to evade first-pass metabolism in the liver and achieve high concentrations of curcumin in plasma and tissues, including the brain.

Role of Inflammatory Cytokines in the Conversion of Mild Cognitive Im- pairment to Dementia: A Prospective Study

BACKGROUND

The effect that cytokines can exert on the progression from mild cognitive impairment (MCI) to ongoing dementia is a matter of debate and the results obtained so far are controversial.

OBJECTIVE

The aim of the study is to analyze the influence of markers of subclinical inflammation on the progression of MCI to dementia.

METHODS

A prospective study involving a cohort of patients ≥ 65 years of age diagnosed with MCI and followed for 3 years was conducted. 105 patients were enrolled, and serum concentrations of several subclinical inflammatory markers were determined.

RESULTS

After 3.09 (2 - 3.79) years of follow-up, 47 (44.76%) patients progressed to dementia. Alpha 1-antichymotrypsin (ACT) was found to be significantly higher in patients who progressed to dementia (486.45 ± 169.18 vs. 400.91 ± 163.03; p = 0.012), and observed to significantly increase the risk of developing dementia in patients with mild cognitive impairment (1.004, 1.001-1.007; p= 0.007). IL-10 levels were significantly higher in those who remained stable (6.69 ± 18.1 vs. 32.54 ± 89.6; p = 0.04). Regarding the type of dementia to which our patients progressed, we found that patients who developed mixed dementia had higher IL-4 levels than those who converted to AD (31.54 ± 63.6 vs. 4.43 ± 12.9; p = 0.03). No significant differences were observed between the groups with regard to the ESR and LPa, CRP, IL-1 and TNF-α levels.

CONCLUSION

ACT levels have a significant predictive value in the conversion of MCI to dementia. IL-10 levels could be a protective factor. It is necessary to conduct studies with serial determinations of these and other inflammatory markers in order to determine their effect on the progression of MCI to dementia.

Longitudinal associations between C-reactive protein and cognitive performance in normative cognitive ageing and dementia

BACKGROUND

systemic inflammation appears to play an important role in the pathogenesis and expression of Alzheimer's disease and other dementias. Previous research has found that elevated levels of serum C-reactive protein (CRP) is associated with poorer cognitive functioning and increased risk for dementia. However, most studies are limited by single CRP measurements, which fail to capture long-term inflammatory exposures or dynamic changes in inflammation and cognition which may occur across repeated measurements.

METHODS

using data from 3,563 older adults aged 65-101 from the Health and Retirement Study, we examined bivariate changes in CRP and cognition measured repeatedly over a 10-year follow-up. Bivariate multilevel models estimated the effect of time-varying CRP on cognition among cognitively healthy older adults and in a subset of 427 participants who reported incident dementia onset during the follow-up period.

RESULTS

in cognitively healthy participants, CRP was associated with lower level of cognitive functioning, but not rate of change over time. This effect was significant in participants under 80 years of age (b = -0.09, standard error (SE) = 0.05, P = 0.04), but not in older participants. In participants with incident dementia, those with higher CRP experienced smaller rates of cognitive decline, leading up to dementia diagnosis.

CONCLUSIONS

elevated levels of CRP predict poorer cognition and increased dementia risk in cognitively healthy adults under the age of 80. Conversely, increased CRP may confer protective effects on cognition in the prodromal stage of dementia.

Inflammatory Cascade in Alzheimer's Disease Pathogenesis: A Review of Experimental Findings

Alzheimer’s disease (AD) is the leading cause of dementia worldwide. Most AD patients develop the disease in late life, named late onset AD (LOAD). Currently, the most recognized explanation for AD pathology is the amyloid cascade hypothesis. It is assumed that amyloid beta (Aβ) aggregation and deposition are critical pathogenic processes in AD, leading to the formation of amyloid plaques, as well as neurofibrillary tangles, neuronal cell death, synaptic degeneration, and dementia. In LOAD, the causes of Aβ accumulation and neuronal loss are not completely clear. Importantly, the blood–brain barrier (BBB) disruption seems to present an essential role in the induction of neuroinflammation and consequent AD development. In addition, we propose that the systemic inflammation triggered by conditions like metabolic diseases or infections are causative factors of BBB disruption, coexistent inflammatory cascade and, ultimately, the neurodegeneration observed in AD. In this regard, the use of anti-inflammatory molecules could be an interesting strategy to treat, delay or even halt AD onset and progression. Herein, we review the inflammatory cascade and underlying mechanisms involved in AD pathogenesis and revise the anti-inflammatory effects of compounds as emerging therapeutic drugs against AD.

Gender- and age-related differences of statin use on incident dementia in patients with rheumatoid arthritis: a Nationwide population-based cohort study

Background

Some observational studies have found a significant association between the use of statin and a reduced risk of dementia. However, the results of these studies are unclear in patients with rheumatoid arthritis (RA). This study is to determine the association between the use of statins and the incidence of dementia according to sex and age-related differences in patients with RA.

Methods

We conducted a nationwide retrospective cohort study using the Taiwan Health Insurance Review and Assessment Service database (2003–2016). The primary outcome assessed was the risk of dementia by estimating hazard ratios (HRs) and 95% confidence intervals (CIs). Multiple Cox regression was used to estimate the adjusted hazard ratio of new-onset dementia. Subgroup analysis was also conducted.

Results

Among the 264,036 eligible patients with RA aged > 40 years, statin users were compared with non-statin users by propensity score matching at a ratio of 1:1 (25,764 in each group). However, no association was found between the use of statins and the risk of new-onset dementia (NOD) in patients with RA (HR: 1.01; 95% CI: 0.97–1.06). The subgroup analysis identified the use of statin as having a protective effect against developing NOD in male and older patients.

Conclusion

No association was observed between the use of a statin and the risk of NOD in patients with RA, including patients of both genders and aged 40–60 years, but these parameters were affected by gender and age. The decreased risk of NOD in patients with RA was greater among older male patients. Use of a statin in older male (> 60 years) patients with RA may be needed in clinical practice to prevent dementia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01465-1.

Inflammation and Coagulation during Critical Illness and Long-Term Cognitive Impairment and Disability

Rationale: The biological mechanisms of long-term cognitive impairment and disability after critical illness are unclear.Objectives: To test the hypothesis that markers of acute inflammation and coagulation are associated with subsequent long-term cognitive impairment and disability.Methods: We obtained plasma samples from adults with respiratory failure or shock on Study Days 1, 3, and 5 and measured concentrations of CRP (C-reactive protein), IFN-γ, IL-1β, IL-6, IL-8, IL-10, IL-12, MMP-9 (matrix metalloproteinase-9), TNF-α (tumor necrosis factor-α), soluble TNF receptor 1, and protein C. At 3 and 12 months after discharge, we assessed global cognition, executive function, and activities of daily living. We analyzed associations between markers and outcomes using multivariable regression, adjusting for age, sex, education, comorbidities, baseline cognition, doses of sedatives and opioids, stroke risk (in cognitive models), and baseline disability scores (in disability models).Measurements and Main Results: We included 548 participants who were a median (interquartile range) of 62 (53-72) years old, 88% of whom were mechanically ventilated, and who had an enrollment Sequential Organ Failure Assessment score of 9 (7-11). After adjusting for covariates, no markers were associated with long-term cognitive function. Two markers, CRP and MMP-9, were associated with greater disability in basic and instrumental activities of daily living at 3 and 12 months. No other markers were consistently associated with disability outcomes.Conclusions: Markers of systemic inflammation and coagulation measured early during critical illness are not associated with long-term cognitive outcomes and demonstrate inconsistent associations with disability outcomes. Future studies that pair longitudinal measurement of inflammation and related pathways throughout the course of critical illness and during recovery with long-term outcomes are needed.

A Highly Selective In Vitro JNK3 Inhibitor, FMU200, Restores Mitochondrial Membrane Potential and Reduces Oxidative Stress and Apoptosis in SH-SY5Y Cells

Current treatments for neurodegenerative diseases (ND) are symptomatic and do not affect disease progression. Slowing this progression remains a crucial unmet need for patients and their families. c-Jun N-terminal kinase 3 (JNK3) are related to several ND hallmarks including apoptosis, oxidative stress, excitotoxicity, mitochondrial dysfunction, and neuroinflammation. JNK inhibitors can play an important role in addressing neuroprotection. This research aims to evaluate the neuroprotective, anti-inflammatory, and antioxidant effects of a synthetic compound (FMU200) with known JNK3 inhibitory activity in SH-SY5Y and RAW264.7 cell lines. SH-SY5Y cells were pretreated with FMU200 and cell damage was induced by 6-hydroxydopamine (6-OHDA) or hydrogen peroxide (H₂O₂). Cell viability and neuroprotective effect were assessed with an MTT assay. Flow cytometric analysis was performed to evaluate cell apoptosis. The H₂O₂-induced reactive oxygen species (ROS) generation and mitochondrial membrane potential (ΔΨm) were evaluated by DCFDA and JC-1 assays, respectively. The anti-inflammatory effect was determined in LPS-induced RAW264.7 cells by ELISA assay. In undifferentiated SH-SY5Y cells, FMU200 decreased neurotoxicity induced by 6-OHDA in approximately 20%. In RA-differentiated cells, FMU200 diminished cell death in approximately 40% and 90% after 24 and 48 h treatment, respectively. FMU200 reduced both early and late apoptotic cells, decreased ROS levels, restored mitochondrial membrane potential, and downregulated JNK phosphorylation after H₂O₂ exposure. In LPS-stimulated RAW264.7 cells, FMU200 reduced TNF-α levels after a 3 h treatment. FMU200 protects neuroblastoma SH-SY5Y cells against 6-OHDA- and H₂O₂-induced apoptosis, which may result from suppressing the JNK pathways. Our findings show that FMU200 can be a useful candidate for the treatment of neurodegenerative disorders.

Neuroprotective Biomarkers and Cognitive Function in a Long-Term Prospective Population-based Study of Aging US Adults

BACKGROUND

Relationships between brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF-1), aldosterone, and cognition in aging were evaluated in the population-based Epidemiology of Hearing Loss Study (1993 to present).

METHODS

Beginning in 1998 to 2000, cognitive impairment was assessed by report of physician diagnoses and the Mini-Mental State Examination. In 2009 to 2010 and 2013 to 2016, information was collected on diagnosis of mild cognitive impairment/dementia. Decline in cognitive function was assessed by principal component analysis from additional tests administered during 2009 to 2010 and 2013 to 2016. BDNF, IGF-1, and aldosterone were measured in serum collected in 1998 to 2000.

RESULTS

There were 1970 participants (mean age=66.9 y; 59.1% female) without cognitive impairment at baseline. Among women, low BDNF was associated with 16-year incident cognitive impairment [hazard ratio=1.76; 95% confidence interval (CI)=1.04, 2.98]. Among men, increasing IGF-1 was associated with decreased risk [per SD: relative risk (RR)=0.57; 95% CI=0.35, 0.92], whereas increasing aldosterone levels were associated with increased risk (per SD: RR=1.28; 95% CI=1.01, 1.62) for 5-year incident mild cognitive impairment/dementia. Overall, low BDNF was associated with increased risk (RR=1.52; 95% CI=1.02, 2.26) for 5-year cognitive decline.

CONCLUSION

Low levels of serum BDNF and IGF-1 were associated with poorer cognition during aging. There may be differential biomarker effects by sex.

Macular Ganglion Cell-Inner Plexiform Layer as a Marker of Cognitive and Sensory Function in Midlife

BACKGROUND

Neurodegenerative diseases are public health challenges in aging populations. Early identification of people at risk for neurodegeneration might improve targeted treatment. Noninvasive, inexpensive screening tools are lacking but are of great potential. Optical coherence tomography (OCT) measures the thickness of nerve cell layers in the retina, which is an anatomical extension of the brain and might be indicative of common underlying neurodegeneration. We aimed to determine the association of macular ganglion cell-inner plexiform layer (mGCIPL) thickness with cognitive and sensorineural function in midlife.

METHOD

This cross-sectional study included 1,880 Beaver Dam Offspring Study participants (aged 27-93 years, mean 58) who participated in the 10-year follow-up examination. We assessed cognitive function and impairment, hearing sensitivity thresholds and impairment, central auditory processing, visual impairment, and olfactory impairment. We measured mGCIPL using the Cirrus 5000 HD-OCT Macular Cube Scan. Multivariable linear and logistic regression models adjusted for potential confounders were used to determine associations between mGCIPL thickness and cognitive and sensorineural functions, as well as for comparing participants with a thin mGCIPL (1 SD below average) to the remainder in those functions.

RESULTS

Thinner mGCIPL was associated with worse cognitive function, worse central auditory function, and visual impairment. We found an association of mGCIPL thickness with hearing sensitivity in women only and no association with impairment in hearing, olfaction, and cognition. Results on the thin group comparisons were consistent.

CONCLUSIONS

mGCIPL thickness is associated with cognitive and sensorineural function and has the potential as a marker for neurodegeneration in middle-aged adults.

Periodontal disease as a possible cause for Alzheimer's disease

Approximately 47 million people worldwide have been diagnosed with dementia, 60%-80% of whom have dementia of the Alzheimer's disease type. Unfortunately, there is no cure in sight. Defining modifiable risk factors for Alzheimer's disease may have a significant impact on its prevalence. An increasing body of evidence suggests that chronic inflammation and microbial dysbiosis are risk factors for Alzheimer's disease. Periodontal disease is a chronic inflammatory disease that develops in response to response to microbial dysbiosis. Many studies have shown an association between periodontal disease and Alzheimer's disease. The intent of this paper was to review the existing literature and determine, using the Bradford Hill criteria, whether periodontal disease is causally related to Alzheimer's disease.

Oxiracetam Offers Neuroprotection by Reducing Amyloid β-Induced Microglial Activation and Inflammation in Alzheimer's Disease

Background: Alzheimer's disease (AD) is characterized by amyloid beta (Aβ) accumulation in the brain, which triggers the activation of microglia; in turn, microglia release neuroinflammatory factors capable of damaging neurons. Thus, a therapeutic approach targeting this sustained microglia-induced inflammatory response deserves investigation. Here, we examined whether oxiracetam (ORC), a nootropic of the racetam family, can indirectly prevent Aβ-induced neurotoxicity by attenuating microglial activation.

Methods: Aβ42 oligomers were used to stimulate BV2 microglial cells, and the morphological changes and phagocytic capacity of BV2 cells were evaluated using fluorescence microscopy. We used quantitative reverse transcription polymerase chain reaction to assess the inhibitory effects of ORC on Aβ-induced mRNA levels of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α); enzyme-linked immunosorbent assay was used to examine the productions of these cytokines. We also assessed the mRNA level of inducible nitric oxide synthase and the production of nitric oxide (NO). The conditioned medium from BV2 cells was used to culture hippocampal HT22 cells to assess indirect toxicity using the MTT assay.

Results: ORC prevented the Aβ-induced activation of BV2 cells, as reflected by reduced morphological changes and phagocytic ability. In addition, ORC downregulated the expression of Aβ-induced cytokines (IL-1β, IL-6, and TNF-α) and the production of NO in BV2 cells. Furthermore, ORC protected HT22 cells from indirect damage evoked by Aβ-treated BV2 cell-conditioned medium, but not from direct Aβ-induced toxicity.

Conclusions: ORC suppressed the activation of BV2 cells, decreased the production of Aβ-induced inflammatory molecules and NO in BV2 cells, and protected HT22 cells against indirect toxicity mediated by Aβ-treated BV2 cell-conditioned medium. Thus, ORC may exert a protective role in AD through attenuating the damage caused by inflammation and oxidative stress.

Sleep Duration Change and Cognitive Function: A National Cohort Study of Chinese People Older than 45 Years

This study aimed to investigate the relationship between sleep duration and cognitive function in Chinese people older than 45 years, using data from the China Health and Retirement Longitudinal Study. The baseline survey was conducted in 2011 and the second and third wave surveys were conducted in 2013 and 2015, respectively. Multiple linear regression models were used to evaluate all associations. A total of 5811 individuals were included. No significant associations were found between short or long sleep duration at baseline and cognitive function. Compared with no change in sleep duration, a decrease in sleep duration by 2 hours or more and an increase in sleep duration by 2 hours or more were associated with worse global cognitive function, with β (95% confidence intervals [CIs]) of -0.42 (-0.70 to -0.14) and -0.34 (-0.67 to -0.01), respectively. In men, an increase of 2 hours or more in sleep duration was associated with lower global cognitive score (β = -0.64; 95% CI, -1.19 to -0.08), whereas in women, a decrease of 2 hours or more in sleep duration was associated with lower global cognitive score (β = -0.42; 95% CI, -0.78 to -0.06). Our study demonstrated that longitudinal sleep duration change was associated with cognitive function. Our findings indicate the need to consider changes in sleep duration when estimating risk and suggest that targeted strategies should be put forward for routine sleep screening and to maintain regular sleep patterns.

Contra-Directional Expression of Plasma Superoxide Dismutase with Lipoprotein Cholesterol and High-Sensitivity C-reactive Protein as Important Markers of Parkinson's Disease Severity

Aim: Oxidative stress and inflammation play critical roles in the neuropathogenesis of PD. We aimed to evaluate oxidative stress and inflammation status by measuring serum superoxide dismutase (SOD) with lipoprotein cholesterol and high-sensitivity C-reactive protein (hsCRP) respectively in PD patients, and explore their correlation with the disease severity.

Methods: We performed a cross-sectional study that included 204 PD patients and 204 age-matched healthy controls (HCs). Plasma levels of SOD, hsCRP, total cholesterol, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were measured. A series of neuropsychological assessments were performed to rate the severity of PD.

Results: The plasma levels of SOD (135.7 ± 20.14 vs. 147.2 ± 24.34, P < 0.0001), total cholesterol, HDL-C and LDL-C in PD were significantly lower than those in HCs; the hsCRP level was remarkably increased in PD compared to HC (2.766 ± 3.242 vs. 1.637 ± 1.597, P < 0.0001). The plasma SOD was negatively correlated with the hsCRP, while positively correlated with total cholesterol, HDL-C, and LDL-C in PD patients. The plasma SOD were negatively correlated with H&Y, total UPDRS, UPDRS (I), UPDRS (II), and UPDRS (III) scores, but positively correlated with MoCA and MMSE scores. Besides, hsCRP was negatively correlated with MoCA; while total cholesterol, HDL-C and LDL-C were positively correlated with the MoCA, respectively.

Conclusion: Our findings suggest that lower SOD along with cholesterol, HDL-C and LDL-C, and higher hsCRP levels might be important markers to assess the PD severity. A better understanding of SOD and hsCRP may yield insights into the pathogenesis of PD.

Elevated blood neutrophil to lymphocyte ratio in older adults with cognitive impairment

BACKGROUND

Previous studies have assessed the association of neutrophil to lymphocyte ratio (NLR) with cognitive impairment (COI) in clinical settings. Whether NLR is associated with COI among free-living seniors at population level remains unknown.

OBJECTIVES

We aimed to assess the relationship between NLR and COI among community-dwelling older adults and the predictive value of NLR for COI screening in the community.

METHODS

Data of 4579 older adults aged 60 or older in Weitang Geriatric Diseases study, a community-based cross-sectional study conducted in Suzhou located in the east part of China, were analyzed. The NLR was calculated as the absolute neutrophil count divided by the absolute lymphocyte count. Cognitive function of the participants was assessed using the Abbreviated Mental Test.

RESULTS

Compared to those in the first quartile of NLR, older adults in the 4th quartile of NLR had a greater risk of COI (odds ratio = 1.34, 95 % confidence interval = 1.06-1.69). Elevated NLR quartile was associated with increasing risk of COI (p value for trend = 0.02). Addition of NLR to the conventional risk factors model could improve the correct reclassification of COI about 9.0 % (p = 0.02) and integrated discrimination improvement value was 0.0012 (p = 0.09).

CONCLUSIONS

We found that elevated NLR was associated with an increased risk of COI and whether NLR may act as a clinically relevant predictor for COI among community-dwelling older adults could not be determined.

Aging-related changes in fluid intelligence, muscle and adipose mass, and sex-specific immunologic mediation: A longitudinal UK Biobank study

BACKGROUND

Obesity in midlife and early late-life is associated with worse normal cognitive aging. Dual-energy X-ray absorptiometry (DEXA) suggests that visceral adipose mass (VAM) plays a predominant role, whereas non-visceral adipose mass (NVAM) and lean muscle mass (LMM) have shown conflicting relationships. It is unknown how longitudinal, cognitive changes in age-sensitive domains like fluid intelligence (FI) correspond to VAM, NVAM, and LMM in women and men. Furthermore, changes over time in blood leukocyte sub-populations may partially or fully account for sex-specific associations.

METHODS

Data on 4431 late middle-aged, cognitively unimpaired adults (mean = 64.5 y) was obtained from the UK Biobank prospective cohort across 22 centers. FI scores, blood leukocyte counts, and covariates (age, social class, education) were measured at three 2-year intervals over 6 years. DEXA collection overlapped with these intervals. Sex-stratified growth curves, structural equations, and Preacher-Hayes mediation were used to estimate direct and indirect effects. β-weights were standardized.

RESULTS

More LMM predicted gains in FI scores among women (β = 0.130, p < .001) and men (β = 0.089, p < .001). Conversely, more VAM and NVAM independently predicted FI decline equally among sexes (e.g., NVAM: women: β = -0.082, p < .001; men: β = -0.076, p < .001). Among women, FI associations were fully mediated by higher eosinophil counts via VAM (λ = 30.8%, p = .028) and lower lymphocyte counts via LMM (λ = 69.2%, p = .021). Among men, FI associations were partially mediated by lower basophils counts via LMM (λ = 4.5%, p = .042) and higher counts via VAM (λ = 50%, p = .037).

CONCLUSION

The proportion of LMM and VAM equally influenced male FI changes over 6 years, whereas higher LMM among women appeared to more strongly influence. FI changes. Leukocyte counts strongly mediated VAM- and LMM-related FI changes in a sex-specific manner, but not for NVAM. For clinical translation, exercise studies in older adults may benefit from assessing sex-specific values of DEXA-based tissue mass, FI, and leukocyte sub-populations to gauge potential cognitive benefits of less VAM and more LMM.

Association of 10-Year C-Reactive Protein Trajectories With Markers of Healthy Aging: Findings From the English Longitudinal Study of Aging

Background

Elevated systematic inflammation is a hallmark of aging, but the association of long-term inflammation trajectories with subsequent aging phenotypes has been little examined. We assessed inflammatory marker C-reactive protein (CRP) repeatedly over time and examined whether long-term changes predicted aging outcomes.

Methods

A total of 2,437 men and women aged 47–87 years at baseline (1998–2001) who were participants in the English Longitudinal Study of Ageing had CRP measured on two or three occasions between 1998 and 2009. Inflammation trajectories were computed using latent-class growth mixture modeling and were related to aging outcomes measured in 2012/2013: physical functioning, cardiometabolic, respiratory, mental health, and a composite “healthy aging” outcome.

Results

Four CRP trajectories were identified as follows: “stable-low” (71 per cent of the sample) with baseline mean 1.33 mg/L remaining <3 mg/L; “medium-to-high” (14 per cent) with baseline 2.7 mg/L rising to 5.3 mg/L; “high-to-medium” (10 per cent) with baseline 6.6 mg/L decreasing to 2.4 mg/L; and “stable-high” (5 per cent) with levels from 5.7 to 7.5 mg/L. Relative to the stable-low trajectory, individuals in the medium-to-high had a higher risk of limitations in basic activities of daily living (ADL, odds ratio; 95% confidence interval: 2.09; 1.51, 2.88), instrumental ADL (1.62; 1.15, 2.30), impaired balance (1.59; 1.20, 2.11) and walking speed (1.61; 1.15, 2.24), arthritis (1.55; 1.16, 2.06), hypertension (1.57; 1.21, 2.04), obesity (1.95; 1.36, 2.80), poor respiratory function (1.84; 1.36, 2.50), and depression (1.55; 1.13, 2.12). A lower odds of healthy aging was observed in people in the medium-to-high (0.57; 0.40, 0.79) and stable-high (0.50; 0.27, 0.91) trajectories.

Conclusions

Older people who displayed an elevation in CRP levels over a decade experienced an increased risk of adverse aging outcomes.

Trajectories of (Bio)markers During the Development of Cognitive Frailty in the Doetinchem Cohort Study

Background: Long-term changes in (bio)markers for cognitive frailty are not well characterized. Therefore, our aim is to explore (bio)marker trajectories in adults who became cognitively frail compared to age- and sex-matched controls who did not become cognitively frail over a 15 year follow-up. We hypothesize that those who become cognitively frail have more unfavorable trajectories of (bio)markers compared to controls. Methods: The Doetinchem Cohort Study is a longitudinal population-based study that started in 1987-1991 in men and women aged 20-59 years, with follow-up examinations every 5 years. For the current analyses, we used data of 17 potentially relevant (bio)markers (e.g., body mass index (BMI), urea) from rounds 2 to 5 (1993-2012). A global cognitive functioning score (based on memory, speed, and flexibility) was calculated for each round and transformed into education and examination round-adjusted z-scores. The z-score that corresponded to the 10th percentile in round 5 (z-score = -0.77) was applied as cut-off point for incident cognitive frailty in rounds 2-5. In total, 455 incident cognitively frail cases were identified retrospectively and were compared with 910 age- and sex-matched controls. Trajectories up to 15 years before and 10 years after incident cognitive frailty were analyzed using generalized estimating equations with stratification for sex and adjustment for age and, if appropriate, medication use. Results were further adjusted for level of education, depressive symptoms, BMI, and lifestyle factors. Results: In men, (bio)marker trajectories did not differ as they ran parallel and the difference in levels was not statistically significant between those who became cognitively frail compared to controls. In women, total cholesterol trajectories first increased and thereafter decreased in cognitively frail women and steadily increased in controls, gamma-glutamyltransferase trajectories were more or less stable in cognitively frail women and increased in controls, and urea trajectories increased in cognitively frail women and remained more or less stable in controls. Results were similar after additional adjustment for potential confounders. Conclusions: Out of the 17 (bio)markers included in this explorative study, differential trajectories for three biomarkers were observed in women. We do not yet consider any of the studied (bio)markers as promising biomarkers for cognitive frailty.

Brain Aging in Midlife: The Beaver Dam Offspring Study

OBJECTIVES

Middle age has been identified as a critical time period for health later in life. Identifying factors associated with worse brain function in middle-aged adults may help identify ways to preserve brain function with aging. Our objective was to evaluate factors associated with a novel measure of brain aging in middle-aged and older adults.

DESIGN

Longitudinal cohort study.

SETTING

Beaver Dam Offspring Study (BOSS) baseline (2005-2008), 5-year (2010-2013), and 10-year examinations (2015-2017).

PARTICIPANTS

A total of 2285 adults, 22 to 84 years of age, with complete sensorineural and neurocognitive data at the 5-year examination.

MEASUREMENTS

Principal component analysis (PCA) was performed combining 5-year sensorineural (hearing, vision, olfaction) and cognitive (Trail Making Test A and B, Digit Symbol Substitution Test, Verbal Fluency Test, Auditory Verbal Learning Test) test data. Participants with a standardized PCA score less than -1 were classified as having brain aging. Incident brain aging was defined as a PCA score less than -1 at 10 years among participants who had a PCA score of -1 or higher at 5 years. Logistic regression and Poisson models were used to estimate associations between baseline factors and prevalent or incident brain aging, respectively.

RESULTS

Older age, being male, current smoking, larger waist circumference, not consuming alcohol, cardiovascular disease, and interleukin-6 were associated with greater odds of prevalent brain aging, whereas more education and exercise were associated with decreased odds. In addition to age and sex, less than a college education, higher levels of soluble intercellular adhesion molecule-1, diabetes, depressive symptoms, and history of head injury were associated with an increased 5-year risk of incident brain aging.

CONCLUSION

In the current study, vascular and inflammatory factors were associated with a new brain aging marker in middle-aged and older adults. Many of these factors are modifiable, highlighting the importance of addressing health and lifestyle factors in midlife to potentially preserve function for better brain health later in life. J Am Geriatr Soc 67:1610-1616, 2019.

Development and psychometric properties of the Healthy Aging Activity Engagement Scale (HAAE)

OBJECTIVES

Accumulating research indicates that engaging in healthy lifestyle behaviors (e.g. exercise, cognitive and social engagement, stress reduction) can prevent illness and disability as people age and improve mental health. The Healthy Aging Activity Engagement (HAAE) scale was developed to holistically assess an individual's level of engagement in healthy aging behaviors across multiple health domains.

METHODS

Participants were 275 healthy younger, midlife and older adults. Participants rated engagement in 38 healthy aging lifestyle behaviors over the past 7 days on a scale from 1 (strongly disagree) to 5 (strongly agree).

RESULTS

Traditional measurement analysis and Rasch modelling techniques resulted in a 32-item scale with three subscales representing biologic health, social and cognitive strategies, and health safeguard behaviors. With the exception of the health safeguard subscale, the HAAE total score and subscales demonstrated good internal consistency, test-retest reliability, convergent and discriminant validity, and responsiveness to a program designed to promote engagement in healthy brain aging behaviors.

DISCUSSION

With further validation, the HAAE may be useful for holistic clinical assessment of behaviors that promote healthy aging, support brain and mental health, and for treatment planning. Furthermore, the HAAE can be used to measure the outcome of multi-domain lifestyle interventions.

The kynurenine pathway and cognitive performance in community-dwelling older adults. The Hordaland Health Study

INTRODUCTION

Tryptophan, its downstream metabolites in the kynurenine pathway and neopterin have been associated with inflammation and dementia. We aimed to study the associations between plasma levels of these metabolites and cognitive function in community-dwelling, older adults.

METHODS

This cross-sectional study included 2174 participants aged 70-72 years of the community-based Hordaland Health Study. Tryptophan, kynurenine, neopterin and eight downstream kynurenines were measured in plasma. Kendrick Object Learning Test (KOLT), Digit Symbol Test (DST) and the Controlled Oral Word Association Test (COWAT) were all outcomes in standardized Zellner's regression. The Wald test of a composite linear hypothesis of an association with each metabolite was adjusted by the Bonferroni method. Age, body mass index, C-reactive protein, depressive symptoms, diabetes, education, glomerular filtration rate, hypertension, previous myocardial infarction, prior stroke, pyridoxal 5'phosphate, sex and smoking were considered as potential confounders.

RESULTS

Higher levels of the kynurenine-to-tryptophan ratio (KTR) and neopterin were significantly associated with poorer, overall cognitive performance (p < 0.002). Specifically, KTR was negatively associated with KOLT (β -0.08, p = 0.001) and COWAT (β -0.08, p = 0.001), but not with DST (β -0.03, p = 0.160). This pattern was also seen for neopterin (KOLT: β -0.07; p = 0.001; COWAT: β -0.06, p = 0.010; DST: β -0.01, p = 0.800). The associations were not confounded by the examined variables. No significant associations were found between the eight downstream kynurenines and cognition.

CONCLUSION

Higher KTR and neopterin levels, biomarkers of cellular immune activation, were associated with reduced cognitive performance, implying an association between the innate immune system, memory, and language.

Vitamin K status and inflammation are associated with cognition in older Irish adults

Studies have shown associations between reduced vitamin K status and poor cognitive function. However, despite this apparent link, direct studies measuring cognitive function, vitamin K status and inflammation are lacking. In the current study, The ELDERMET cohort was investigated to identify associations between cognition, vitamin K status and inflammation. The primary aim of the ELDERMET study was to investigate the relationship between gut bacteria, diet, lifestyle and health in 500 older Irish adults. Significant differences in serum phylloquinone, dietary phylloquinone and inflammatory markers were found across varying levels of cognitive function, after controlling for sex, age, body mass index (BMI), triglycerides and blood pressure. In addition, significantly higher levels of dietary phylloquinone were found in those with better cognition compared to those with the poorest function. Higher levels of inflammatory were also associated with poor cognition. Furthermore, both dietary and serum phylloquinone were significant independent predictors of good cognitive function, after controlling for confounders. This study highlights the importance of dietary vitamin K as a potentially protective cognitive factor; it also provides evidence for the correlation between cognition and inflammation. Strategies should be devised by which elderly populations can access rich dietary sources of phylloquinone to maintain cognition.

Cognitive impairments induced by severe acute pancreatitis are attenuated by berberine treatment in rats

Cognitive impairments induced by severe acute pancreatitis (SAP) are severe complications, for which there are a lack of effective pharmacological treatment strategies. Berberine is an isoquinoline alkaloid extracted from the Chinese herb, Coptis rhizome, which exhibits numerous biological effects on gastrointestinal disorders. However, the effects of berberine on SAP‑induced cognitive impairments remain unknown. The present study aimed to investigate the effects of berberine on cognitive impairments associated with SAP. Wistar rats were randomly divided into Sham, Sham + berberine, SAP and SAP + berberine groups. Rats were intraperitoneally injected with L‑arginine (3 g/kg) to induce SAP. Subsequently, selected rats were intragastrically administered berberine (100 mg/kg) once daily for 6 consecutive days. Disease severities of rats were investigated 48 h post‑induction of SAP via determination of serum amylase levels and hematoxylin and eosin staining. Survival rates, performance of behavioral tests (automated rotarod and fear conditioning tests), blood brain barrier (BBB) permeability, and the expression levels of tumor necrosis factor (TNF)‑α and interleukin (IL)‑1β in hippocampal tissues were also determined. Proteins associated with apoptosis and necroptosis in the hippocampal tissues of SAP rats, including caspase‑3, receptor‑interacting protein kinase (RIP)1 and RIP3, were detected via western blotting. The results revealed that treatment with L‑arginine induced SAP, which subsequently resulted in increased BBB permeability, mortality rates and cognitive deficits in rats. The expression levels of TNF‑α, IL‑1β, caspase‑3, RIP1 and RIP3 were significantly increased in the hippocampal tissues of SAP rats, thus suggesting that neuroinflammation, apoptosis and necroptosis may be involved in neurodegeneration associated with the development of SAP. Notably, administration of berberine protected the integrity of the BBB, decreased levels of brain inflammation and mortality rates, and attenuated increased levels of proteins associated with apoptosis and necroptosis and cognitive deficits associated with SAP in rats. The results of the present study demonstrated that daily treatment with berberine may attenuate cognitive deficits and reduce associated mortality via exhibition of anti‑neuroinflammatory effects and attenuation of neuronal apoptosis and necroptosis in the hippocampal tissues of SAP rats.

Independent and Differential Effects of Obesity and Hypertension on Cognitive and Functional Abilities

Objective

The primary aim of this study was to identify the independent and differential associations of obesity and hypertension with cognitive, physical, and directly observed functional abilities among middle age and older adults.

Method

Participants were 119 adults between the ages of 51 and 89, who underwent a cross-sectional assessment of cognitive, physical, functional and relevant health-related variables.

Results

Obesity predicted significantly poorer executive functions (β = -.301, t = -3.86, p < .001), mobility (β = .329, t = 3.59, p < .001), observed functional abilities (β = .220, t = 2.52, p = .013), and self-reported ability to perform activities of daily living that require physical capability (β = -.365, t = -4.23, p < .001). In contrast, hypertension was not independently associated with any of the outcome measures (ps > .05). Results from the path analysis revealed that executive functions mediated the association between obesity and poorer directly observed functional abilities. Additionally, obesity had a direct and indirect (through mobility) effect on self-reported basic activities of daily living.

Conclusions

These findings suggest a link between obesity, executive functions, and limitations in physical function and instrumental activities of daily living among middle age and older adults, however, longitudinal research is needed to further delineate the trajectory of these factors.

An Epidemiologic Study of the Association between Free Recall Dichotic Digits Test Performance and Vascular Health

BACKGROUND

Associations between vascular health-related factors and hearing loss defined using audiometric pure-tone thresholds have been found. Studies have not focused on a potential relationship between vascular health-related factors and central auditory processing.

PURPOSE

The aim of this study was to evaluate, on a population level, the relationship of vascular health-related factors with central auditory function.

RESEARCH DESIGN

A cross-sectional, population study.

STUDY SAMPLE

Subjects were participants in the Epidemiology of Hearing Loss Study (EHLS) or the Beaver Dam Offspring Study (BOSS)-prospective studies of aging and sensory loss. BOSS participants were the adult offspring of participants in the EHLS. Participants who completed the Dichotic Digits Test (DDT) during the fourth examination period of the EHLS (2008-2010) or the second examination period of the BOSS (2010-2013) were included (n = 3,655, mean age = 61.1 years).

DATA COLLECTION AND ANALYSIS

The DDT-free recall test was conducted using 25 sets of triple-digit pairs at a 70 dB HL presentation level. The total number of correctly repeated digits from the right and left ears was converted to a percentage correct and used as an outcome. The percentage correct in the left ear was subtracted from the percentage correct in the right ear and used as an outcome. Vascular health-related measures obtained during the examination included blood pressure, mean carotid intima-media thickness, femoral pulse wave velocity (PWV), hemoglobin A1C, and non-high-density lipoprotein (HDL) cholesterol, and, in the EHLS participants, C-reactive protein and interleukin-6. Information on vascular health-related history and behaviors was self-reported. General linear modeling produced estimates of the age- and sex-adjusted least squares means for each vascular factor, and multiple linear regression was used for multivariable modeling of each outcome.

RESULTS

After multivariable adjustment, participants with diabetes had a significantly lower (worse) mean DDT-free recall total score (-2.08 percentage points, p < 0.001) than those without diabetes. Participants who exercised at least once per week had a significantly higher (better) mean DDT-free recall total score (+1.07 percentage points, p < 0.01) than those who did not exercise at least once per week. Alcohol consumption was associated with a higher DDT-free recall total score (+0.15 percentage points per +25 g ethanol, p < 0.01). In multivariable modeling of the right-left ear difference in DDT-free recall scores, participants with a history of cardiovascular disease (CVD) or higher PWV demonstrated significantly larger differences (CVD: +3.11 percentage points, p = 0.02; PWV: +0.36 percentage points per 1 m/sec, p < 0.01). Higher levels of non-HDL cholesterol were associated with smaller right-left ear differences (-0.22 percentage points per 10 mg/dL, p = 0.01). Adjustment for handedness did not affect the results.

CONCLUSIONS

Vascular health-related factors may play a role in central auditory function.

Does the Interplay Between Aging and Neuroinflammation Modulate Alzheimer's Disease Clinical Phenotypes? A Clinico-Pathological Perspective

Alzheimer's disease (AD) is a chronic neurodegenerative disorder and is the most common cause of dementia worldwide. Cumulative data suggests that neuroinflammation plays a prominent and early role in AD, and there is compelling data from different research groups of age-associated dysregulation of the neuroimmune system. From the clinical point of view, despite clinical resemblance and neuropathological findings, there are important differences between the group of patients with sporadic early-onset (<65 years old) and late-onset AD (>65 years old). Thus, it seems important to understand the age-dependent relationship between neuroinflammation and the underlying biology of AD in order to identify potential explanations for clinical heterogeneity, interpret biomarkers, and promote the best treatment to different clinical AD phenotypes. The study of the delicate balance between pro-inflammatory or anti-inflammatory sides of immune players in the different ages of onset of AD would be important to understand treatment efficacy in clinical trials and eventually, not only direct treatment to early disease stages, but also the possibility of establishing different treatment approaches depending on the age of the patient. In this review, we would like to summarize what is currently known about the interplay between "normal" age associated inflammatory changes and AD pathological mechanisms, and also the potential differences between early-onset and late-onset AD taking into account the age-related neuroimmune background at disease onset.