Biomarkers.

Background: The MarkVCID consortium was established to address the paucity of biomarkers for vascular contributions to cognitive impairment and dementia (VCID), a leading cause of dementia. Plasma neurofilament light (NfL), a neuroaxonal injury marker elevated in several neurological and neurodegenerative diseases, was selected as one of the first biomarkers to be examined. We performed comprehensive instrumental and clinical validation of the Quanterix Simoa NfL assay using the first MarkVCID cohort.

Demographic and Clinical Characteristics Associated With Serum GFAP Levels in an Ethnically Diverse Cohort.

Background And Objectives: Elevations in circulating glial fibrillary acidic protein (GFAP), a putative marker of reactive astrocytosis, have been found to associate with cognitive decline and dementia status. Further validation in diverse cohorts and evaluation of potential health disparities are necessary for broader generalization. The goal of this study was to examine the associations between demographics, cardiovascular risk factors, and APOE ε4 status with serum GFAP levels among Mexican American and non-Hispanic White older adults across the continuum from cognitively unimpaired to Alzheimer disease dementia.

Immune Dysregulation in Acute SARS-CoV-2 Infection.

Introduction: Neutralizing antibodies have been shown to develop rapidly following SARS-CoV-2 infection, specifically against spike (S) protein, where cytokine release and production is understood to drive the humoral immune response during acute infection. Thus, we evaluated the quantity and function of antibodies across disease severities and analyzed the associated inflammatory and coagulation pathways to identify acute markers that correlate with antibody response following infection.

Methods: Blood samples were collected from patients at time of diagnostic SARS-CoV-2 PCR testing between March 2020-November 2020.

Siglec-9 Restrains Antibody-Dependent Natural Killer Cell Cytotoxicity against SARS-CoV-2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection alters the immunological profiles of natural killer (NK) cells. However, whether NK antiviral functions are impaired during severe coronavirus disease 2019 (COVID-19) and what host factors modulate these functions remain unclear. We found that NK cells from hospitalized COVID-19 patients degranulate less against SARS-CoV-2 antigen-expressing cells (in direct cytolytic and antibody-dependent cell cytotoxicity [ADCC] assays) than NK cells from mild COVID-19 patients or negative controls.

Plasma biomarkers predict cognitive trajectories in an ethnoracially and clinically diverse cohort: Mediation with hippocampal volume.

Introduction: We examine whether the association between key plasma biomarkers (amyloid β [aβ] 42/40, total tau (t-tau), neurofilament light [NfL]) and cognitive trajectories (executive function [EF] and episodic memory [EM]) is mediated through neurodegeneration.

Methods: All participants were recruited from the University of California, Davis-Alzheimer's Disease Research Center ( = 473; baseline age range = 49-95 years, 60% women). We applied an accelerated longitudinal design to test latent growth models for EF and EM, and path and mediation analyses.

A population-based meta-analysis of circulating GFAP for cognition and dementia risk.

Objective: Expression of glial fibrillary acidic protein (GFAP), a marker of reactive astrocytosis, colocalizes with neuropathology in the brain. Blood levels of GFAP have been associated with cognitive decline and dementia status. However, further examinations at a population-based level are necessary to broaden generalizability to community settings.

Blood biomarkers for cognitive decline and clinical progression in a Mexican American cohort.

: The clinical translation of biofluid markers for dementia requires validation in diverse cohorts. The study goal was to evaluate if blood biomarkers reflecting diverse pathophysiological processes predict disease progression in Mexican American adults. : Mexican American adults (n = 745), 50 years of age and older, completed annual assessments over a mean of 4 years.

SARS-CoV-2 seropositivity and subsequent infection risk in healthy young adults: a prospective cohort study.

Background: Whether young adults who are infected with SARS-CoV-2 are at risk of subsequent infection is uncertain. We investigated the risk of subsequent SARS-CoV-2 infection among young adults seropositive for a previous infection.

Methods: This analysis was performed as part of the prospective COVID-19 Health Action Response for Marines study (CHARM).

Online social and professional support for smokers trying to quit: an exploration of first time posts from 2562 members.

Background: Both intratreatment and extratreatment social support are associated with increased rates of smoking cessation. Internet-based social support groups have the capability of connecting widely dispersed groups of people trying to quit smoking, making social support available 24 hours a day, seven days a week, at minimal cost. However, to date there has been little research to guide development of this particular feature of Web-assisted tobacco interventions (WATIs).