A gene-environment interplay between omega-3 supplementation and APOE ε4 provides insights for Alzheimer's disease precise prevention amongst high-genetic-risk population.

BACKGROUND AND PURPOSE: The present study aimed to explore whether and how omega-3 (ω-3) supplementation could interact with genetic factors to modulate cognitive functions, amyloid pathologies, and Alzheimer's disease (AD) risk. METHODS: A total of 1,670 non-demented participants (mean age 73 years, 47% females, 41% APOE ε4 carriers) were followed up for 10 years. Hierarchical regressions, linear mixed-effects models, and Cox proportional hazards models were used to examine the interaction effects of ω-3 supplementation with APOE ε4 and polygenic hazard scores, after adjusting for age, gender, education, cognitive diagnosis, insomnia, depression, anxiety, and cardiovascular risk score. RESULTS: Individuals who progress to AD during the follow-up tend to take a shorter duration of ω-3 at baseline than those stable, for whom the difference remained significant only amongst APOE ε4 carriers (p < 0.01). The interaction term (APOE ε4 × ω-3) accounted for a significant amount of variance in cognition and cerebral amyloid burden. Long-term ω-3 use protected cognition (especially memory function) and lowered amyloid burden and AD risk only amongst APOE ε4 carriers. Mediation analysis suggested that amyloid pathologies, brain reserve capacities, and brain metabolism mediated the relationships of ω-3 use with memory and global cognition for APOE ε4 (+) carriers. Similar interaction and mediation effects were also indicated amongst high-risk subjects defined by polygenic hazard scores. CONCLUSIONS: Long-term ω-3 intake may have a role in AD prevention in genetically at-risk populations.

The Relationship of Omega-3 Fatty Acids with Dementia and Cognitive Decline: Evidence from Prospective Cohort Studies of Supplementation, Dietary Intake, and Blood Markers.

Previous data have linked omega-3 fatty acids with risk of dementia. We aimed to assess the longitudinal relationships of omega-3 polyunsaturated fatty acid intake as well as blood biomarkers with risk of Alzheimer's disease (AD), dementia, or cognitive decline. Longitudinal data were derived from 1135 participants without dementia (mean age = 73 y) in the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort to evaluate the associations of omega-3 fatty acid supplementation and blood biomarkers with incident AD during the 6-y follow-up. A meta-analysis of published cohort studies was further conducted to test the longitudinal relationships of dietary intake of omega-3 and its peripheral markers with all-cause dementia or cognitive decline. Causal dose-response analyses were conducted using the robust error meta-regression model. In the ADNI cohort, long-term users of omega-3 fatty acid supplements exhibited a 64% reduced risk of AD (hazard ratio: 0.36, 95% confidence interval: 0.18, 0.72; P = 0.004). After incorporating 48 longitudinal studies involving 103,651 participants, a moderate-to-high level of evidence suggested that dietary intake of omega-3 fatty acids could lower risk of all-cause dementia or cognitive decline by ∼20%, especially for docosahexaenoic acid (DHA) intake (relative risk [RR]: 0.82, I2 = 63.6%, P = 0.001) and for studies that were adjusted for apolipoprotein APOE ε4 status (RR: 0.83, I2 = 65%, P = 0.006). Each increment of 0.1 g/d of DHA or eicosapentaenoic acid (EPA) intake was associated with an 8% ∼ 9.9% (Plinear < 0.0005) lower risk of cognitive decline. Moderate-to-high levels of evidence indicated that elevated levels of plasma EPA (RR: 0.88, I2 = 38.1%) and erythrocyte membrane DHA (RR: 0.94, I2 = 0.4%) were associated with a lower risk of cognitive decline. Dietary intake or long-term supplementation of omega-3 fatty acids may help reduce risk of AD or cognitive decline.

[Karyotypic analysis from two clones of gynogenetic Pengze crucian carp (Carassius auratus of Pengze)].

Pengze crucian carp (Carassius auratus of pengze), one of the most popular cultural fishes in China, is an endemic bisexual population with natural gynogenetic reproduction mode. Just like Silver crucian carp, investigation on the karyotype of Pengze crucian carp is important to understanding the diversity and the evolution of the unisexual vertebrates. Two distinguishable gynogenetic clones of Pengze crucian carp, named clone H and clone L, respectively,were detected recently. In this study, the chromosomes number and karyotype of the two clones were analyzed using chromosomes of kidney cell-PHA culture in vivo prepared by flame-drying technique. The results show that the chromosome numbers and karyotypes of the two clones are different. Clone H has 156 chromosomes in its karyotype with 42 metacentric, 36 submetacentric, 39 subtelocentric, 33 telocentric, and six supernumerary chromosomes; the karyotype of clone L contains 162 chromosomes with 36 metacentric, 45 submetacentric, 33 subtelocentric, 36 telocentric, and twelve supernumerary chromosomes. The karyotype formula of 150 basic chromosomes of clone H is 3n = 42M +36SM +39ST +33T,NF = 228; and the karyotype formula of 150 basic chromosomes of clone L is 3n = 36M +45SM +33ST +36T, NF = 231. The discovery of the two different gynogenetic clones indicates that the genetic diversity also exists in the Pengze crucian carp, similar to that in the Silver crucian carp.