Genetic and environmental influences on cardiovascular risk factors and cognitive function: A Chinese twin aging study

Dyadic contagion in cognitive function: A nationally-representative longitudinal study of older U.S. couples

Later-life cognitive function is strongly influenced by one's environment. At this life stage, a partner's behaviors and attributes-including their own cognitive status-are a key environmental determinant. A recent "social allostasis" theory also yields specific predictions on patterns of mutual influence-or "contagion"-in cognitive function. Yet, no population representative studies have examined these coupled dynamics. Using recently developed fixed-effects cross-lagged panel modeling (FE-CLPM) methods and ten-year data from the Health and Retirement Study-nationally-representative of U.S. adults over 50-the current study filled this gap. Results supported dyadic cognitive contagion over the long- but not short-run. Short-term associations suggested intriguing "cognitive cycling" possibilities among both men and women that need further investigation. Overall, results supported a theoretical model of coupled "cognitive careers," and relational inducement of allostatic load. Especially among men, recurrent impulses also cumulatively induced substantial path-dependent cognitive improvements, supporting the added value of repeated over one-time interventions. Theoretical and substantive implications are discussed.

Co-methylation analyses identify CpGs associated with lipid traits in Chinese discordant monozygotic twins

To control genetic background and early life milieu in genome-wide DNA methylation analysis for blood lipids, we recruited Chinese discordant monozygotic twins to explore the relationships between DNA methylations and total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). 132 monozygotic (MZ) twins were included with discordant lipid levels and completed data. A linear mixed model was conducted in Epigenome-wide association study (EWAS). Generalized estimating equation model was for gene expression analysis. We conducted Weighted correlation network analysis (WGCNA) to build co-methylated interconnected network. Additional Qingdao citizens were recruited for validation. Inference about Causation through Examination of Familial Confounding (ICE FALCON) was used to infer the possible direction of these relationships. A total of 476 top CpGs reached suggestively significant level (P < 10-4), of which, 192 CpGs were significantly associated with TG (FDR < 0.05). They were used to build interconnected network and highlight crucial genes from WGCNA. Finally, four CpGs in GATA4 were validated as risk factors for TC; six CpGs at ITFG2-AS1 were negatively associated with TG; two CpGs in PLXND1 played protective roles in HDL-C. ICE FALCON indicated abnormal TC was regarded as the consequence of DNA methylation in CpGs at GATA4, rather than vice versa. Four CpGs in ITFG2-AS1 were both causes and consequences of modified TG levels. Our results indicated that DNA methylation levels of 12 CpGs in GATA4, ITFG2-AS1, and PLXND1 were relevant to TC, TG, and HDL-C, respectively, which might provide new epigenetic insights into potential clinical treatment of dyslipidemia.

Coenzyme Q10 ameliorates aging-induced memory deficits via modulation of apoptosis, oxidative stress, and mitophagy in aged rats

The behavioral effects and molecular signaling mechanisms of Coenzyme Q₁₀ (Q₁₀) in age-related memory impairment are poorly understood. This study aimed to investigate the effects of Q₁₀ on memory impairment, oxidative stress, apoptosis, and mitophagy in aged rats. 40 aged (24 months old) and 10 young (3 months old) male Wistar rats were randomly divided into the following groups (n = 10/group): young + vehicle, aged + vehicle, and aged + Q₁₀ (at 100, 200, 300 mg/kg/day doses). Treatments were administrated orally by gavage for 2 weeks. The novel object recognition test was used to assess episodic memory. Oxidative stress, apoptosis, and mitophagy-related protein expressions were measured in the hippocampus. We found that Q10 reversed aging-induced memory impairment at the dose of 300 mg/kg. Moreover, aging was associated with a reduction in ATP production, decrease in mitophagy-related proteins (PINK, Parkin, and P62 levels and LC3II/I ratio), excessive generation of reactive oxygen species and lipid peroxidation, and apoptosis in the hippocampus, which were partially reversed following oral administration of Q₁₀. These findings indicate the therapeutic potential of Q₁₀ in aging-induced memory decline.

Analysis of genetic and environmental correlation between leisure activities and cognitive function in aging Chinese twins

OBJECTIVE

Leisure activity has been shown to be beneficial to mental health and cognitive aging. The biological basis of the correlation is, however, poorly understood. This study aimed at exploring the genetic and environmental impacts on correlation between leisure activities and cognitive function in the Chinese middle- and old-aged twins.

METHODS

Cognition measured using a screening test (Montreal Cognitive Assessment, MoCA) and leisure activities including intellectual and social activity were investigated on 379 complete twin pairs of middle- and old-aged twins. Univariate and bivariate twin models were fitted to estimate the genetic and environmental components in their variance and covariance.

RESULTS

Moderate heritability was estimated for leisure activities and cognition (0.44-0.53) but insignificant for social activity. Common environmental factors accounted for about 0.36 of the total variance to social activity with no significant contribution to leisure activity, intellectual activity and cognition. Unique environmental factors displayed moderate contributions (0.47-0.64) to leisure activities and cognition. Bivariate analysis showed highly and positively genetic correlations between leisure activities and cognition (r_G=0.80-0.96). Besides, intellectual activity and cognition presented low but significant unique environmental correlation (r_E=0.12).

CONCLUSIONS

Genetic factor had the moderate contribution to leisure activities and cognition. Cognitive function was highly genetically related to leisure activities. Intellectual activity and cognitive function may share some unique environmental basis.

Religious attendance and global cognitive function: A fixed-effects cross-lagged panel modeling study of older U.S. adults

OBJECTIVES

Evidence linking religious attendance to better cognitive function is based on flawed study designs. No population representative longitudinal studies on the topic have taken both unobserved confounding and reverse causation into account. Recently developed fixed-effects cross-lagged panel modeling (FE-CLPM) offers simultaneous traction on these issues. It also allows parsing of long-from short-run effects. Using FE-CLPM and ten-year data from the Health and Retirement Study-a national probability sample of U.S. adults over age 50-this study began to fill the gaps above.

METHODS

Gender-specific FE-CLPM models were used to examine bidirectional and within-person linkages of religious attendance with global cognitive function. Granger-Sims "causality" tests further examined short-run effects in both directions. Impulse response analysis was used to explore time patterns in these linkages.

RESULTS

At least among women, religious attendance had negative short-term prospective linkages with global cognitive function. Over successive time points, these associations increased in strength among both genders. Feedback effects-of cognitive status on religious attendance-were found in both women's and men's models, but had a gender-specific pattern.

DISCUSSION

Results contradict a large literature positing cognitive benefits of religiosity. Instead, they lend support to a recent "neural resource depletion" model-especially among women. Overall, findings illustrate the "dark side" of religious engagement, which studies increasingly present as a social determinant with "outcome wide" positive effects on multiple health dimensions.

The relational genomics of cognitive function: A longitudinal study

OBJECTIVES

Research in social genetics indicates a person's genome may influence outcomes of those in close relationships. Implications for cognitive function remain unexplored. The current study examined such "metagenomic" patterns among older U.S. couples.

METHODS

Data were from married or cohabiting couples in the 2006-2016 waves of the Health and Retirement Study, nationally representative of U.S. adults over 50. Measures included cognitive function as well as separate polygenic scores for cognition and for educational attainment. Analysis was through parallel process latent growth models.

RESULTS

Consistent with a recent "genetic externalities" conception, one partner's polygenic score for educational attainment was linked to the other's baseline levels of cognitive function. Contrary to relational moderation speculations, neither a partner's genetic scores nor educational attainment altered individual-level genetic influences.

DISCUSSION

Findings add to the growing evidence that transpersonal genetic influences in one's proximal context have substantively important implications. Research is needed on the role of non-partnership ties in channeling such effects. Implications for life course theory are discussed.

Associations between PHACTR1 gene polymorphisms and pulse pressure in Chinese Han population

A genome-wide association study (GWAS) in Chinese twins was performed to explore associations between genes and pulse pressure (PP) in 2012, and detected a suggestive association in the phosphatase and actin regulator 1 (PHACTR1) gene on chromosome 6p24.1 (rs1223397, P=1.04e⁻⁰⁷). The purpose of the present study was to investigate associations of PHACTR1 gene polymorphisms with PP in a Chinese population. We recruited 347 subjects with PP ≥ 65 mmHg as cases and 359 subjects with 30 ≤ PP ≤ 45 mmHg as controls. Seven single nucleotide polymorphisms (SNPs) in the PHACTR1 gene were genotyped. Logistic regression was performed to explore associations between SNPs and PP in codominant, additive, dominant, recessive and overdominant models. The Pearson’s χ² test was applied to assess the relationships of haplotypes and PP. The A allele of rs9349379 had a positive effect on high PP. Multivariate logistic regression analysis showed that rs9349379 was significantly related to high PP in codominant [AA vs GG, 2.255 (1.132–4.492)], additive [GG vs GA vs AA, 1.368 (1.049–1.783)] and recessive [AA vs GA + GG, 2.062 (1.051–4.045)] models. The positive association between rs499818 and high PP was significant in codominant [AA vs GG, 3.483 (1.044–11.613)] and recessive [AA vs GG + GA, 3.716 (1.119–12.339)] models. No significant association of haplotypes with PP was detected. There was no significant interaction between six SNPs without strong linkage. In conclusion, the present study presents that rs9349379 and rs499818 in the PHACTR1 gene were significantly associated with PP in Chinese population. Future research should be conducted to confirm them.

Heritability and Genome-Wide Association Study of Plasma Cholesterol in Chinese Adult Twins

Dyslipidemia represents a strong and independent risk factor for cardiovascular disease. Plasma cholesterol, such as total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), and high density lipoprotein cholesterol (HDL-C), is the common indicator of diagnosing dyslipidemia. Here based on 382 Chinese twin pairs, we explored the magnitude of genetic impact on TC, HDL-C, LDL-C variation and further searched for genetic susceptibility loci for them using genome-wide association study (GWAS). The ACE model was the best fit model with additive genetic parameter (A) accounting for 26.6%, common or shared environmental parameter (C) accounting for 47.8%, unique/non-shared environmental parameter (E) accounting for 25.6% for the variance in HDL-C. The AE model was the best fit model for TC (A: 61.4%; E: 38.6%) and LDL-C (A: 65.5%; E: 34.5%). While no SNPs reached the genome-wide significance level (P < 5 × 10^-8), 8, 14, 9 SNPs exceeded the suggestive significance level (P < 1 × 10^-5) for TC, HDL-C, LDL-C, respectively. The promising genetic regions for TC, HDL-C, LDL-C were on chromosome 11 around rs7107698, chromosome 5 around rs12518218, chromosome 2 around rs10490120, respectively. Gene-based analysis found 1038, 1033 and 1090 genes nominally associated with TC, HDL-C, LDL-C (P < 0.05), especially FAF1, KLKB1 for TC, KLKB1 for HDL-C, and NTRK1, FAF1, SNTB2 for LDL-C, respectively. The number of common related genes among TC, HDL-C and LDL-C was 71, including FAF1, KLKB1, etc. Pathway enrichment analysis discovered known related pathways-zinc transporters, metal ion SLC transporters for TC, cell adhesion molecules CAMs, IL-6 signaling for HDL, FC epsilon RI signaling pathway, NFAT pathway for LDL, respectively. In conclusion, the TC and LDL-C level is moderately heritable and the HDL-C level is lowly heritable in Chinese population. The genomic loci, functional genes and pathways are identified to account for the heritability of plasma cholesterol level. Our findings provide important insights into plasma cholesterol molecular physiology and expect future research to replicate and validate our results.