Anger suppression and adiposity modulate association between ADRB2 haplotype and cardiovascular stress reactivity

When Anger Remains Unspoken: Anger and Accelerated Epigenetic Aging Among Stress-Exposed Black Americans

OBJECTIVE

Race-related lifetime stress exposure (LSE) including racial discrimination, trauma, and stressful life events have been shown to contribute to racial health disparities. However, little is known about associations between race-related stressors and premature biological aging that confer the risk of adverse health outcomes. Even less is known about the mechanisms through which race-related stressors may be associated with accelerated aging. Early evidence suggests psychological processes such as anger, and particularly the internalization of anger, may play a role.

METHODS

In a community sample of predominantly low-income Black adults (n = 219; age = 45.91 [12.33] years; 64% female), the present study examined the association of race-related LSE (as defined by exposure to racial discrimination, trauma, and stressful life events) and epigenetic age acceleration through anger expression.

RESULTS

Internalized and externalized anger expression were each significantly associated with LSE and age acceleration. Although LSE was not directly associated with age acceleration (ΔR2 = 0.001, p = .64), we found that greater LSE was indirectly associated with age acceleration through increases in internalized, but not externalized, anger (indirect effect: β = 0.03, standard error = 0.02, 95% confidence interval = 0.003 to 0.08; total effect: β = 0.02, 95% confidence interval = -0.25 to 0.31).

CONCLUSIONS

These results suggest race-related LSE may elicit the internalization of anger, which, along with the externalization of anger, may initiate detrimental epigenetic alterations that confer the risk of adverse health outcomes. These findings lay the groundwork for longitudinal studies of the association between race-related stress and racial health disparities.

Ethnic Differences in Resting Total Peripheral Resistance: A Systematic Review and Meta-Analysis

OBJECTIVE

Decades of research suggest that there may be important ethnic differences in the hemodynamic mechanisms that co-determine arterial blood pressure, the primary diagnostic index of hypertension. In general, studies have observed that, compared with European Americans (EAs), African Americans (AAs) exhibit higher total peripheral resistance (TPR), an important summative index of peripheral vascular constriction. In contrast, EAs have been reliably shown to exhibit greater cardiac output (CO), which is directly linked to left ventricle and overall cardiac blood flow. We have previously proposed that elevated basal TPR, in particular, represents one component of the cardiovascular conundrum, characterized, paradoxically, by elevated resting heart rate variability among AAs relative to EAs. The present meta-analysis and systematic review of the literature sought to extend this previous work by establishing the magnitude of the empirically implied ethnic differences in resting TPR and CO.

METHODS

A search of the literature yielded 140 abstracts on differences in TPR between AAs and EAs; 40 were included. Sample sizes, means, and standard deviations for baseline TPR with samples that included EAs and AAs were collected, and Hedges g was computed.

RESULTS

Findings indicated that AAs had higher baseline TPR than did EAs (Hedges g = 0.307, SE = 0.043, confidence interval= 0.224 to 0.391, p < .001). In addition, EAs had higher resting CO than did AAs (Hedges g = -0.214, SE = 0.056, confidence interval = -0.324 to -0.104, p < .001).

CONCLUSIONS

We discuss the present findings in the context of the role of elevated TPR in the deleterious effects of high blood pressure specifically for AAs.

rs2572431 Polymorphism on Chromosome 8 Is Associated With Individual Differences in Anxiety Related Coping Modes

OBJECTIVE

The role of genetic factors in the interplay between anxiety-related coping and personality has been the subject of interest in numerous previous studies. The current study focused on anxiety-related coping modes, namely repression versus sensitization (i.e., cognitive avoidance versus vigilance), and the single nucleotide polymorphism (SNP) rs2572431. An association between this SNP and anxiety-related personality traits has previously been shown in a genome wide association study, thus further investigation of the relationship between this SNP and anxiety-related coping seems warranted.

METHODS

In the present study, N = 880 mostly Caucasian participants (n = 269 males and n = 611 females; mean-age: 23.88, SD = 7.19) filled in a personality questionnaire assessing individual differences in cognitive avoidance and vigilance, and all participants were genotyped for rs2572431.

RESULTS

Participants homozygous for the T-allele in rs2572431 showed the highest vigilance scores in all scenarios tested. This is in line with findings from an earlier genome wide association study demonstrating that the T-allele is also associated with higher neuroticism scores.

CONCLUSION

The current study yields evidence for the role of rs2572431 in the molecular genetic underpinnings of coping modes and, more broadly, for its connection with personality.

Association of the ADRB2 (rs2053044) polymorphism and angiotensin-converting enzyme-inhibitor blood pressure response in the African American Study of Kidney Disease and Hypertension

AIM/OBJECTIVES/BACKGROUND

Hypertension is a risk factor for cardiovascular and kidney disease and is most prevalent in African-American adults. The renin-angiotensin-aldosterone system is integral in blood pressure regulation; angiotensin-converting enzyme inhibitors such as ramipril are first-line treatment options. As decreases in angiotensin result in catecholamine release, β-adrenergic receptor (ADRB) polymorphisms may influence blood pressure response to ramipril.

METHODS

Associations between ADRB polymorphisms and blood pressure response to ramipril were analyzed in the African American Study of Kidney Disease and Hypertension, a randomized clinical trial. A total of 336 participants were included in this analysis. Six polymorphisms were analyzed here: (a) ADRB1 rs1801252 (Ser49Gly) and rs1801253 (Gly389Arg); and (b) ADRB2 rs2053044, rs1042711, rs1042713 (Arg16Gly), and rs1042714 (Gln27Glu). Time to reach a mean arterial pressure (MAP) of 107 mmHg within the first 60 days after randomization was studied using Kaplan-Meier and Cox proportional hazards modeling for univariate and adjusted analyses.

RESULTS

Genotypes at rs2053044, upstream from the ADRB2 5' untranslated region, were associated with time to reach target MAP among those randomized to the usual treatment group. Participants with the GG genotype achieved target MAP on average 12.2 days (38.1%) later than in comparison with those with the A allele (P=0.01). After adjusting for covariates, those with the AA/AG genotype had 2.09 greater odds of reaching MAP of 107 mmHg or less within 60 days of treatment in comparison with those with a GG genotype (hazard ratio=2.09, 95% confidence interval=1.21-3.60).

CONCLUSION

Results suggest that ADRB2 rs2053044 genotypes may be a determinant of blood pressure response to ramipril. Additional studies are needed to clarify the effect of rs2053044 and other 5' untranslated region polymorphisms on gene expression and blood pressure response to angiotensin-converting enzyme inhibitors.

Raiva, Stress Emocional e Hipertensão: Um Estudo Comparativo

RESUMO O estudo teve como objetivo investigar uma possível associação entre direção de expressão de raiva e stress em pessoas com hipertensão a partir da comparação com pessoas sem esse diagnóstico. Foram avaliados 112 participantes: 56 com hipertensão e 56 normotensos, pareados por escolaridade, gênero e faixa etária. Os instrumentos utilizados foram o Inventário de Sintomas de Stress para Adultos de Lipp e o Inventário de Expressão de Raiva como Estado e Traço. Participantes com hipertensão apresentaram 9,7 vezes mais chances de estarem estressados que normotensos (OR=9,7; IC95%:4,0-23,5) e 19 vezes mais chances de expressarem raiva para dentro (OR=19; IC95%:5,3-68).

Genome-wide linkage and regional association study of blood pressure response to the cold pressor test in Han Chinese: the genetic epidemiology network of salt sensitivity study

BACKGROUND

Blood pressure (BP) response to cold pressor test (CPT) is associated with increased risk of cardiovascular disease. We performed a genome-wide linkage scan and regional association analysis to identify genetic determinants of BP response to CPT.

METHODS AND RESULTS

A total of 1961 Chinese participants completed the CPT. Multipoint quantitative trait linkage analysis was performed, followed by single-marker and gene-based analyses of variants in promising linkage regions (logarithm of odds ≥2). A suggestive linkage signal was identified for systolic BP response to CPT at 20p13 to 20p12.3, with a maximum multipoint logarithm of odds score of 2.37. On the basis of regional association analysis with 1351 single nucleotide polymorphisms in the linkage region, we found that marker rs2326373 at 20p13 was significantly associated with mean arterial pressure responses to CPT (P=8.8×10(-6)) after false discovery rate adjustment for multiple comparisons. A similar trend was also observed for systolic BP response (P=0.03) and diastolic BP response (P=4.6×10(-5)). Results of gene-based analyses showed that variants in genes MCM8 and SLC23A2 were associated with systolic BP response to CPT (P=4.0×10(-5) and 2.7×10(-4), respectively), and variants in genes MCM8 and STK35 were associated with mean arterial pressure response to CPT (P=1.5×10(-5) and 5.0×10(-5), respectively).

CONCLUSIONS

Within a suggestive linkage region on chromosome 20, we identified a novel variant associated with BP responses to CPT. We also found gene-based associations of MCM8, SLC23A2, and STK35 in this region. Additional work is warranted to confirm these findings.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov; Unique identifier: NCT00721721.

A systematic review of genetic influences on coping

Coping refers to the way that an individual manages stress. Coping strategies vary; for example, problem-focused coping is directed at reducing or removing a stressor, while emotion-focused coping is directed more at managing reactions that accompany the stressor. How individuals cope with stress can impact their health, but the physiological effects of coping are not well understood. The field of genetics provides tools that could help illuminate the physiology of coping. This review of the literature was conducted to determine what is currently known about the phenotype of coping from a genetic perspective. PubMed, HubMed, PsychInfo, Medline, Scopus, and Google Scholar databases were used to conduct the search, and reference lists were reviewed to identify additional publications. Only studies that measured coping style or a coping domain specifically, were written in English language, and were human-subject focused were included in the review. We identified 19 studies that met these criteria, and 2 types of genetic studies emerged for the review: heritability (n = 9) and candidate gene association (n = 10) studies. Heritability estimates of .68-.76 support a nonadditive genetic component to coping. Replication of association was found for the serotonin transporter and adrenergic receptor beta 2 genes. In addition to finding evidence supporting a role for genetic variability with coping phenotype, it is worth noting that the review revealed a lack of consistency in instruments used to phenotype coping across studies.

Psychological stress in childhood and susceptibility to the chronic diseases of aging: moving toward a model of behavioral and biological mechanisms

Among people exposed to major psychological stressors in early life, there are elevated rates of morbidity and mortality from chronic diseases of aging. The most compelling data come from studies of children raised in poverty or maltreated by their parents, who show heightened vulnerability to vascular disease, autoimmune disorders, and premature mortality. These findings raise challenging theoretical questions. How does childhood stress get under the skin, at the molecular level, to affect risk for later diseases? And how does it incubate there, giving rise to diseases several decades later? Here we present a biological embedding model, which attempts to address these questions by synthesizing knowledge across several behavioral and biomedical literatures. This model maintains that childhood stress gets "programmed" into macrophages through epigenetic markings, posttranslational modifications, and tissue remodeling. As a consequence these cells are endowed with proinflammatory tendencies, manifest in exaggerated cytokine responses to challenge and decreased sensitivity to inhibitory hormonal signals. The model goes on to propose that over the life course, these proinflammatory tendencies are exacerbated by behavioral proclivities and hormonal dysregulation, themselves the products of exposure to early stress. Behaviorally, the model posits that childhood stress gives rise to excessive threat vigilance, mistrust of others, poor social relationships, impaired self-regulation, and unhealthy lifestyle choices. Hormonally, early stress confers altered patterns of endocrine and autonomic discharge. This milieu amplifies the proinflammatory environment already instantiated by macrophages. Acting in concert with other exposures and genetic liabilities, the resulting inflammation drives forward pathogenic mechanisms that ultimately foster chronic disease.

Beta-adrenergic receptor gene polymorphisms and cardiovascular reactivity to stress in Black adolescents and young adults

Cardiovascular reactivity to stress and beta-adrenergic receptor (beta-AR) function may contribute to the development of hypertension. As Black Americans have an increased risk of hypertension, we evaluated associations between beta(1)-AR (Arg389Gly) and beta(2)-AR (Arg16Gly, Gln27Glu) gene variants and cardiovascular reactivity in 500 Black youth. Heart rate, preejection period, total peripheral resistance, and blood pressure reactivity were measured during cold and psychological stress. The Arg389Gly polymorphism in the beta(1)-AR was associated with preejection period reactivity in males but not in females. The Arg16Gly polymorphism in the beta(2)-AR was associated with diastolic blood pressure reactivity only during video game stress. An association between the Gln27Glu polymorphism in the beta(2)-AR and vascular reactivity depended on sex. Thus, specific patterns of associations emerged between genetic variations in beta-ARs and cardiovascular reactivity in young Blacks.

Genetic influences on cardiovascular stress reactivity

Individual differences in the cardiovascular response to stress play a central role in the reactivity hypothesis linking frequent exposure to psychosocial stress to adverse outcomes in cardiovascular health. To assess the importance of genetic factors, a meta-analysis was performed on all published twin studies that assessed heart rate (HR) or blood pressure (BP) reactivity to the cold pressor test or various mental stress tasks. For reactivity to mental stress, the pooled heritability estimate ranged from 0.26 to 0.43. Reactivity to the cold pressor test yielded heritability estimates from 0.21 to 0.55. An ensuing review of genetic association studies revealed a number of genes, mostly within the sympathoadrenal pathway, that may account for part of the heritability of cardiovascular stress reactivity. Future progress in gene finding, that should include measures of sympathetic and vagal stress reactivity, may help uncover the molecular pathways from genetic variation to stress reactivity.