Cognitive post‐acute sequelae of SARS‐CoV‐2 (PASC) can occur after mild COVID‐19. Detailed clinical characterizations may inform pathogenesis. We evaluated 22 adults reporting cognitive PASC and 10 ...not reporting cognitive symptoms after mild SARS‐CoV‐2 infection through structured interviews, neuropsychological testing, and optional cerebrospinal fluid (CSF) evaluations (53%). Delayed onset of cognitive PASC occurred in 43% and associated with younger age. Cognitive PASC participants had a higher number of pre‐existing cognitive risk factors (2.5 vs. 0; p = 0.03) and higher proportion with abnormal CSF findings (77% vs. 0%; p = 0.01) versus controls. Cognitive risk factors and immunologic mechanisms may contribute to cognitive PASC pathogenesis.
Nearly three out of four survivors experience Cancer-Related Cognitive Impairment (CRCI) for months or years following treatment. Both clinical and animal studies point to the hippocampus as a likely ...brain region affected in CRCI, however no previous study has investigated the functional connectivity of the hippocampus in CRCI. We compared hippocampal connectivity in cancer survivors and healthy controls and tested the relationship between functional connectivity differences and measures of objective and subjective cognition. Exploratory analysis of inflammatory markers was conducted in a small subset of participants as well. FMRI data were acquired during a memory task from 16 breast cancer survivors and 17 controls. The NIH Toolbox was used to assess cognitive performance and Neuro-QoL was used to measure self-reported cognitive concerns. Whole-brain group-level comparisons identified clusters with different connectivity to the hippocampus in survivors versus controls during task. Average connectivity was extracted from clusters of significant difference between the groups and correlated with cognitive performance and subjective report. Survivors performed worse on a test of episodic memory and reported greater cognitive concern than controls. Exploratory analysis found higher IL6 in cancer survivors compared to controls. Cancer survivors demonstrated higher connectivity of hippocampus with left cuneus, left lingual, left precuneus, and right middle prefrontal gyrus compared with controls. In survivors, higher task-related hippocampal-cortical connectivity was related to worse subjective measures of cognitive concern. Of the four significant clusters, higher connectivity of the precuneus with hippocampus was significantly associated with worse cognitive concern in survivors. The observed greater hippocampal-cortical connectivity in survivors compared to controls is the first reported fMRI biomarker of subjective concern, and may represent a compensatory response to cancer and its treatments. This compensation could explain, in part, the subjective feelings of cognitive impairment that were reported by survivors.
•Cancer survivors performed worse on a test of episodic memory and reported greater cognitive concern than controls•Cancer survivors demonstrated significantly higher hippocampal-cortical connectivity•Higher functional connectivity was associated with worse self-reported cognitive functioning in cancer survivors
Measuring plasma glial fibrillary acidic protein (GFAP) alongside cortical amyloid-β (Aβ) may shed light on astrocytic changes in aging and Alzheimer's disease (AD).
To examine associations between ...plasma GFAP and cortical Aβ deposition in older adults across the typical aging-to-AD dementia spectrum.
We studied two independent samples from UCSF (Cohort 1, N = 50; Cohort 2, N = 37) covering the spectra of clinical severity (CDR Sum of Boxes; CDR-SB) and Aβ-PET burden. Aβ-PET was completed with either florbetapir or Pittsburgh Compound B and standardized uptake value ratios were converted to the Centiloid (CL) scale for analyses. All participants with CDR-SB > 0 were Aβ-PET positive, while clinically normal participants (CDR-SB = 0) were a mix of Aβ-PET positive and negative. Regression analyses evaluated main effect and interaction associations between plasma GFAP, Aβ-PET, and clinical severity.
In both cohorts, plasma GFAP increased linearly with Aβ-PET CLs in clinically normal older adults. In Cohort 2, which included participants with more severe clinical dysfunction and Aβ-PET burden, the association between Aβ and GFAP became curvilinear (inverted U-shape; quadratic model R2 change = 0.165, p = 0.009), and Aβ-PET interacted with CDR-SB (R2 change = 0.164, p = 0.007): older adults with intermediate functional impairment (CDR-SB = 0.5-4.0) showed a weak (negative) association between Aβ-PET CLs and plasma GFAP, while older adults with dementia (CDR-SB > 4.0) showed a strong, negative association of higher Aβ-PET CLs with lower plasma GFAP.
The relationship between astrocytic integrity and cortical Aβ may be highly dynamic, with linear, positive associations early in disease that diverge in more severe disease stages.
Despite advances in the development of biomarkers for Alzheimer's disease (AD), accurate ante-mortem diagnosis remains challenging because a variety of neuropathologic disease states can coexist and ...contribute to the AD dementia syndrome. Here, we report a neuroimaging study correlating hippocampal deformity with regional AD and transactive response DNA-binding protein of 43 kDA pathology burden. We used hippocampal shape analysis of ante-mortem T1-weighted structural magnetic resonance imaging images of 42 participants from two longitudinal cohort studies conducted by the Rush Alzheimer's Disease Center. Surfaces were generated for the whole hippocampus and zones approximating the underlying subfields using a previously developed automated image-segmentation pipeline. Multiple linear regression models were constructed to correlate the shape with pathology measures while accounting for covariates, with relationships mapped out onto hippocampal surface locations. A significant relationship existed between higher paired helical filaments–tau burden and inward hippocampal shape deformity in zones approximating CA1 and subiculum which persisted after accounting for coexisting pathologies. No significant patterns of inward surface deformity were associated with amyloid-beta or transactive response DNA-binding protein of 43 kDA after including covariates. Our findings indicate that hippocampal shape deformity measures in surface zones approximating CA1 may represent a biomarker for postmortem AD pathology.
•Higher tau deposition correlates with inward hippocampal deformity on in vivo MRI.•Patterns observed for TDP-43 and amyloid are not significant in the multivariate model.•Hippocampal CA1 deformity is proposed as a biomarker for preclinical AD.
There are minimal data directly comparing plasma neurofilament light (NfL) and glial fibrillary acidic protein (GFAP) in aging and neurodegenerative disease research. We evaluated associations of ...plasma NfL and plasma GFAP with brain volume and cognition in two independent cohorts of older adults diagnosed as clinically normal (CN), mild cognitive impairment (MCI), or Alzheimer's dementia.
We studied 121 total participants (Cohort 1:
= 50, age 71.6 ± 6.9 years, 78% CN, 22% MCI; Cohort 2:
= 71, age 72.2 ± 9.2 years, 45% CN, 25% MCI, 30% dementia). Gray and white matter volumes were obtained for total brain and broad subregions of interest (ROIs). Neuropsychological testing evaluated memory, executive functioning, language, and visuospatial abilities. Plasma samples were analyzed in duplicate for NfL and GFAP using single molecule array assays (Quanterix Simoa). Linear regression models with structural MRI and cognitive outcomes included plasma NfL and GFAP simultaneously along with relevant covariates.
Higher plasma GFAP was associated with lower white matter volume in both cohorts for temporal (Cohort 1:
= -0.33,
= .002; Cohort 2:
= -0.36,
= .03) and parietal ROIs (Cohort 1:
= -0.31,
= .01; Cohort 2:
= -0.35,
= .04). No consistent findings emerged for gray matter volumes. Higher plasma GFAP was associated with lower executive function scores (Cohort 1:
= -0.38,
= .01; Cohort 2:
= -0.36,
= .007). Plasma NfL was not associated with gray or white matter volumes, or cognition after adjusting for plasma GFAP.
Plasma GFAP may be more sensitive to white matter and cognitive changes than plasma NfL. Biomarkers reflecting astroglial pathophysiology may capture complex dynamics of aging and neurodegenerative disease.
Abstract
Blood-based inflammatory markers hold considerable promise for diagnosis and prognostication of age-related neurodegenerative disease, though a paucity of research has empirically tested how ...reliably they can be measured across different experimental runs (“batches”). We quantified the interbatch reliability of 13 cytokines and chemokines in a cross-sectional study of 92 community-dwelling older adults (mean age = 74; 48% female). Plasma aliquots from the same blood draw were parallelly processed in 2 separate batches using the same analytic platform and procedures (high-performance electrochemiluminescence by Meso Scale Discovery). Interbatch correlations (Pearson’s r) ranged from small and nonsignificant (r = .13 for macrophage inflammatory protein-1 alpha MIP-1α) to very large (r > .90 for interferon gamma IFNγ, interleukin-10 IL-10, interferon gamma-induced protein 10 IP-10, MIP-1β, thymus and activation-regulated chemokine TARC) with most markers falling somewhere in between (.67 ≤ r ≤ .90 for IL-6, tumor necrosis factor alpha TNF-α, Eotaxin, Eotaxin-3, monocyte chemoattractant protein-1 MCP-1, MCP-4, macrophage-derived chemokine MDC). All markers, except for IL-6 and MCP-4, showed significant differences in absolute values between batches, with discrepancies ranging in effect size (Cohen’s d) from small to moderate (0.2 ≤ |d| ≤ 0.5 for IL-10, IP-10, MDC) to large or very large (0.68 ≤ |d| ≤ 1.5 for IFNγ, TNF-α, Eotaxin, Eotaxin-3, MCP-1, MIP-1α, MIP-1β, TARC). Relatively consistent associations with external variables of interest (age, sex, systolic blood pressure, body mass index, cognition) were observed across batches. Taken together, our results suggest heterogeneity in measurement reliability of blood-based cytokines and chemokines, with some analytes outperforming others. Future work is needed to evaluate the generalizability of these findings while identifying potential sources of batch effect measurement error.
Cancer survivors have lingering cognitive problems, however the anatomical basis for these problems has yet to be fully elucidated. Clinical studies as well as animal models of chemotherapy have ...pinpointed cell and volume loss to the hippocampus, however, few studies have performed shape analysis of the hippocampus on cancer survivors. This study used high-dimensional deformation mapping analysis to test whether localized hippocampal deformation differs in breast cancer survivors who received adjuvant chemotherapy coupled with hormone blockade therapy, and if deformation was related to subjective self-reported concerns and cognitive performance. 3 T MRI images were acquired from 16 pre-menopausal breast cancer survivors and 18 healthy controls without a history of cancer. Breast cancer survivors had undergone chemotherapy within the eighteen months prior to the study, and were receiving estrogen-blockade therapy at the time of the study. Automated high-dimensional deformation mapping was used to compare localized hippocampal deformation differences between groups. Self-reported subjective concerns were assessed using Neuro-QOL Cognitive Function assessment, whereas cognitive performance was evaluated using the NIH Toolbox Cognition Battery. Relative to healthy controls, cancer survivors showed significantly more inward hippocampal deformation, worse self-reported cognitive functioning, and inferior episodic memory test score. This study is the first of its kind to examine the relationship between hippocampal deformity and cognitive impairment in cancer survivors.
Urinary tract infections (UTIs) represent a major burden across the population, although key facets of their pathophysiology and host interaction remain unclear. Escherichia coli epitomizes these ...obstacles: this gram-negative bacterial species is the most prevalent agent of UTIs worldwide and can also colonize the urogenital tract in a phenomenon known as asymptomatic bacteriuria (ASB). Unfortunately, at the level of the individual E. coli strains, the relationship between UTI and ASB is poorly defined, confounding our understanding of microbial pathogenesis and strategies for clinical management. Unlike diarrheagenic pathotypes of E. coli, the definition of uropathogenic E. coli (UPEC) remains phenomenologic, without conserved phenotypes and known genetic determinants that rigorously distinguish UTI- and ASB-associated strains. This article provides a cross-disciplinary review of the current issues from interrelated mechanistic and diagnostic perspectives and describes new opportunities by which clinical resources can be leveraged to overcome molecular challenges. Specifically, we present our work harnessing a large collection of patient-derived isolates to identify features that do (and do not) distinguish UTI- from ASB-associated E. coli strains. Analyses of biofilm formation, previously reported to be higher in ASB strains, revealed extensive phenotypic heterogeneity that did not correlate with symptomatology. However, metabolomic experiments revealed distinct signatures between ASB and cystitis isolates, including in the purine pathway (previously shown to be critical for intracellular survival during acute infection). Together, these studies demonstrate how large-scale, wild-type approaches can help dissect the physiology of colonization versus infection, suggesting that the molecular definition of UPEC may rest at the level of global bacterial metabolism.
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•Clinical diagnosis of UTI relies on symptoms in cases of pertinent bacterial burden.•No empiric tools reliably distinguish strains of E. coli in cases of ASB versus UTI.•Phenotypic assays cannot predict the disease-state of urinary E. coli isolates.•Global metabolomic analyses reveal signatures of ASB-associated E. coli strains.
In response to the restrictions imposed by the COVID-19 pandemic, the University of California San Francisco Memory and Aging Center (UCSF MAC) has deployed a comprehensive telemedicine model for the ...diagnosis and management of Alzheimer disease and related dementias. This review summarizes a large academic behavioral neurology clinic's experience transitioning to telemedicine services, including the impact on clinic care indicators, access metrics, and provider's experience. We compared these outcomes from 3 years before COVID-19 to 12 months after the transition to video teleconferencing (VTC) encounters.
Patient demographics and appointment data (dates, visit types, and departments) were extracted from our institution's electronic health record database from January 1, 2017, to May 1, 2021. We present data as descriptive statistics and comparisons using Wilcoxon rank-sum tests and Fisher exact tests. The results of anonymous surveys conducted among the clinic's providers are reported as descriptive findings.
After the implementation of telemedicine services, the proportion of clinic encounters completed via VTC increased from 1.9% to 86.4%. There was a statistically significant decline in both the percentage of scheduled appointments that were canceled (32.9% vs 27.9%;
< 0.01) and total cancelations per month (mean 240.3 vs 179.4/mo;
< 0.01). There was an increase in the percentage of completed scheduled appointments (60.2% vs 64.8%;
< 0.01) and an increase in the average estimated commuting distance patients would need to drive for follow-up appointments (mean 49.8 vs 54.7 miles;
< 0.01). The transition to telemedicine services did not significantly affect the clinic's patient population as measured by age, gender, estimated income, area deprivation index, or self-reported racial/ethnic identity. The results of the provider survey revealed that physicians reported a more positive experience relative to neuropsychologists. Both types of providers reported telemedicine services as a reasonable equivalent and acceptable alternative to in-person evaluations with notable caveats.
UCSF MAC's comprehensive integration of telemedicine services maintained critical ambulatory care to patients living with dementia during the COVID-19 pandemic. The recognized benefits of our care model suggest dementia telemedicine may be used as a feasible and equivalent alternative to in-person ambulatory care in the after COVID-19 era.
Objective: We aimed to test the hypothesis that elevated neocortical β-amyloid (Aβ), a hallmark feature of Alzheimer's disease (AD), predicts sex-specific cognitive trajectories in clinically normal ...older adults, with women showing greater risk of decline than men. Method: Florbetapir Aβ positron emission tomography (PET) was acquired in 149 clinically normal older adults (52% female, Mage = 74). Participants underwent cognitive testing at baseline and during annual follow-up visits over a timespan of up to 5.14 years. Mixed-effects regression models evaluated whether relations between baseline neocortical Standardized Uptake Value Ratio (SUVR) and composite scores of episodic memory, executive functioning, and processing speed were moderated by sex (male/female) and apolipoprotein E (APOE) status (ε4 carrier/noncarrier). Results: Higher baseline SUVR was associated with longitudinal decline in episodic memory in women (b = −1.32, p < .001) but not men (b = −0.30, p = .28). Female APOE ε4 carriers with elevated SUVR showed particularly precipitous declines in episodic memory (b = −4.33, p < .001) whereas other cognitive domains were spared. SUVR did not predict changes in executive functioning or processing speed, regardless of sex (ps >.63), though there was a main effect of SUVR on processing speed (b = 2.50, p = .003). Conclusions: Clinically normal women with elevated Aβ are more vulnerable to episodic memory decline than men. Understanding sex-related differences in AD, particularly in preclinical stages, is crucial for guiding precision medicine approaches to early detection and intervention.
Key Points
Question: This study evaluated whether older men and women are differentially susceptible to cognitive decline in very early, presymptomatic stages of the Alzheimer's disease (AD) continuum. Findings: Our results indicated that clinically normal women with elevated β-amyloid (a protein associated with AD that accumulates in the brain) show significantly greater rates of memory decline over time compared with men, especially when they carry the apolipoprotein E (APOE) ε4 allele (a genetic risk factor for AD). Importance: These findings suggest that women are particularly vulnerable to memory changes in early stages of AD and may help to improve early diagnosis and intervention efforts. Next Steps: Future work should investigate biological (e.g., hormonal, immunological, and cardiovascular), sociocultural (e.g., educational and occupational disparities), and other factors that may help to explain why women are disproportionately at risk for early AD-related cognitive changes.
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