Corrigendum: APOE4 allele-specific associations between diet, multimodal biomarkers, and cognition among Puerto Rican adults in Massachusetts.

[This corrects the article DOI: 10.3389/fnagi.2023.1285333.].

APOE4 allele-specific associations between diet, multimodal biomarkers, and cognition among Puerto Rican adults in Massachusetts.

Background: Apolipoprotein E (APOE) is the strongest genetic risk factor for sporadic Alzheimer's Disease (AD), and the ε4 allele (APOE4) may interact with lifestyle factors that relate to brain structural changes, underlying the increased risk of AD. However, the exact role of APOE4 in mediating interactions between the peripheral circulatory system and the central nervous system, and how it may link to brain and cognitive aging requires further elucidation. In this analysis, we investigated the association between APOE4 carrier status and multimodal biomarkers (diet, blood markers, clinical diagnosis, brain structure, and cognition) in the context of gene-environment interactions. Methods: Participants were older adults from a longitudinal observational study, the Boston Puerto Rican Health Study (BPRHS), who self-identified as of Puerto Rican descent. Demographics, APOE genotype, diet, blood, and clinical data were collected at baseline and at approximately 12th year, with the addition of multimodal brain magnetic resonance imaging (MRI) (T1-weighted and diffusion) and cognitive testing acquired at 12-year. Measures were compared between APOE4 carriers and non-carriers, and associations between multimodal variables were examined using correlation and multivariate network analyses within each group. Results: A total of 156 BPRHS participants (mean age at imaging = 68 years, 77% female, mean follow-up 12.7 years) with complete multimodal data were included in the current analysis. APOE4 carriers (n = 43) showed reduced medial temporal lobe (MTL) white matter (WM) microstructural integrity and lower mini-mental state examination (MMSE) score than non-carriers (n = 113). This pattern was consistent with an independent sample from the Alzheimer's Disease Neuroimaging Initiative (ADNI) of n = 283 non-Hispanic White adults without dementia (mean age = 75, 40% female). Within BPRHS, carriers showed distinct connectivity patterns between multimodal biomarkers, characterized by stronger direct network connections between baseline diet/blood markers with 12-year blood/clinical measures, and between blood markers (especially lipids and cytokines) and WM. Cardiovascular burden (i.e., hypertension and diabetes status) was associated with WM integrity for both carriers and non-carriers. Conclusion: APOE4 carrier status affects interactions between dietary factors, multimodal blood biomarkers, and MTL WM integrity across ~12 years of follow-up, which may reflect increased peripheral-central systems crosstalk following blood-brain barrier breakdown in carriers.

Association of Diabetes and Hypertension With Brain Structural Integrity and Cognition in the Boston Puerto Rican Health Study Cohort.

BACKGROUND AND OBJECTIVES: The Boston Puerto Rican Health Study (BPRHS) is a longitudinal study following self-identified Puerto Rican older adults living in the Greater Boston area. Studies have shown higher prevalence of hypertension (HTN) and type 2 diabetes (T2D) within this ethnic group compared to age-matched non-Hispanic White adults. In this study, we investigated the associations of HTN and T2D comorbidity on brain structural integrity and cognitive capacity in community-dwelling Puerto Rican adults and compared these measures with older adult participants (non-Hispanic White and Hispanic) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) and National Alzheimer's Coordinating Center (NACC) databases. METHODS: BPRHS participants who underwent brain MRI and cognitive testing were divided into 4 groups based on their HTN and T2D status: HTN-/T2D-, HTN+/T2D-, HTN-/T2D+, and HTN+/T2D+. We assessed microstructural integrity of white matter (WM) pathways using diffusion MRI, brain macrostructural integrity using hippocampal volumes, and brain age using T1-weighted MRI and cognitive test scores. BPRHS results were then compared with results from non-Hispanic White and Hispanic participants from the ADNI and NACC databases. RESULTS: The prevalence of HTN was almost 2 times (66.7% vs 38.7%) and of T2D was 5 times (31.8% vs 6.6.%) higher in BPRHS than in ADNI non-Hispanic White participants. Diffusion MRI showed clear deterioration patterns in major WM tracts in the HTN+/T2D+ group and, to a lesser extent, in the HTN+/T2D- group compared to the HTN-/T2D- group. HTN+/T2D+ participants also had the smallest hippocampal volume and larger brain aging deviations. Trends toward lower executive function and global cognitive scores were observed in HTN+/T2D+ relative to HTN-/T2D- individuals. MRI measures and the Mini-Mental State Examination (MMSE) scores from the HTN+/T2D+ BPRHS group resembled those of ADNI White participants with progressive mild cognitive impairment (MCI), while the BPRHS HTN-/T2D- participants resembled participants with stable MCI. The BPRHS was not significantly different from the ADNI + NACC Hispanic cohort on imaging or MMSE measures. DISCUSSION: The effects of T2D and HTN comorbidity led to greater brain structural disruptions than HTN alone. The high prevalence of HTN and T2D in the Puerto Rican population may be a key factor contributing to health disparities in cognitive impairment in this group compared to non-Hispanic White adults in the same age range. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov identifier: NCT01231958.

Evaluation of a novel colorimetric assay for free oxygen radicals as marker of oxidative stress.

BACKGROUND: Free oxygen radicals play an important role in the pathogenesis of many diseases including cardiovascular disease, diabetes, hypertension, cancer and aging. Several methods were developed for the direct or indirect measurement of oxygen free radical and its byproducts. The free oxygen radicals monitor (FORM) is a novel point-of-care system for the rapid measurement of free oxygen radicals (FORT) in blood. We have carefully evaluated the use of this assay for batch analysis of plasma samples in a research environment with respect to factors affecting its performance, including storage temperature and duration. METHODS: We determined the effect of storage, hemolysis, variability and reproducibility of the FORT in blood and plasma. RESULTS: Plasma FORT correlated significantly with hsCRP (P<0.0001) and CHOL/HDL ratio (P<0.02). While hsCRP results have shown a greater range of assay variability (27.82%-53.92%), FORT measurements in the same samples have less assay variability (5.63%-9.61%). Collected whole blood can be kept on ice for up to 7 h prior to plasma isolation without affecting FORT values. Storage of plasma has no effect on FORT when stored at 4 degrees C for up to 3 weeks (R(2)=0.685). Comparable values can be obtained in samples stored for up to 3 months at -80 degrees C (R(2)=0.5888) but not at -20 degrees C. CONCLUSIONS: The day to day variability of FORT, as assessed by multiple measures in a group of controls over time, is minimal. FORT assay is stable when stored at -80 degrees C for a couple of months or at 4 degrees C for a few weeks. FORT correlation with hsCRP and other lipid markers provides an interesting insight and a novel link between oxidative stress, inflammation and lipid metabolism.