ARMC 5 Variants and Risk of Hypertension in Blacks: MH- GRID Study

Racial Disparities in Cardiovascular Risk and Cardiovascular Care in Women

PURPOSE OF REVIEW

Research on sex and gender aspects cardiovascular disease has contributed to a reduction in cardiovascular mortality in women. However, cardiovascular disease remains the leading cause of death of women in the United States. Disparities in cardiovascular risk and outcomes among women overall persist and are amplified for women of certain ethnic and racial subgroups. We review the evidence of racial and ethnic differences in cardiovascular risk and care among women and describe a path forward to achieve equitable cardiovascular care for women of racial and ethnic minority groups.

RECENT FINDINGS

There is a disproportionate effect on cardiovascular outcomes in women and certain racial and ethnic groups in part due to disparities in triage, diagnosis, treatment, which lead to amplification of inequalities in women of minority racial and ethnic background. Data suggest gender and racial bias, underappreciation of nontraditional risk factors, underrepresentation of women in clinical trials and undertreatment of disease contributes to persistent differences in cardiovascular disease outcomes in women of color. Understanding the myriad of factors that contribute to increased cardiovascular risk, and disparities in treatment and outcomes among women from racial/ethnic minority backgrounds is imperative to improving cardiovascular care for this patient population.

The accelerated aging phenotype: The role of race and social determinants of health on aging

The pursuit to discover the fundamental biology and mechanisms of aging within the context of the physical and social environment is critical to designing interventions to prevent and treat its complex phenotypes. Aging research is critically linked to understanding health disparities because these inequities shape minority aging, which may proceed on a different trajectory than the overall population. Health disparities are characteristically seen in commonly occurring age-associated diseases such as cardiovascular and cerebrovascular disease as well as diabetes mellitus and cancer. The early appearance and increased severity of age-associated disease among African American and low socioeconomic status (SES) individuals suggests that the factors contributing to the emergence of health disparities may also induce a phenotype of 'premature aging' or 'accelerated aging' or 'weathering'. In marginalized and low SES populations with high rates of early onset age-associated disease the interaction of biologic, psychosocial, socioeconomic and environmental factors may result in a phenotype of accelerated aging biologically similar to premature aging syndromes with increased susceptibility to oxidative stress, premature accumulation of oxidative DNA damage, defects in DNA repair and higher levels of biomarkers of oxidative stress and inflammation. Health disparities, therefore, may be the end product of this complex interaction in populations at high risk. This review will examine the factors that drive both health disparities and the accelerated aging phenotype that ultimately contributes to premature mortality.

What the Jackson Heart Study Has Taught Us About Diabetes and Cardiovascular Disease in the African American Community: a 20-year Appreciation

PURPOSE OF REVIEW

The burden of cardiometabolic diseases such as cardiovascular disease (CVD) and type 2 diabetes (T2D) is pronounced among African Americans. Research has shown that behavioral, social, metabolic, psychosocial, and genetic risk factors of CVD and T2D are closely interwoven. Approximately 20 years ago, the Jackson Heart Study (JHS) was established to investigate this constellation of risk factors.

RECENT FINDINGS

Findings from neighborhood studies emphasize the importance of social cohesion and physical environment in the context CVD and T2D risk. Socioeconomic status factors such as income and education were significant predictors for CVD and T2D. Behavioral studies indicate that modifiable risk factors such as smoking, physical inactivity, lack of sleep, and poor nutrition are associated with CVD risk and all-cause mortality. Mental health also was found to be associated with CVD and T2D. Genetic influences are associated with disease etiology. This review summarizes the joint contributions of CVD and cardiometabolic risk factors in an African American population.

The Association of ARMC5 with the Renin-Angiotensin-Aldosterone System, Blood Pressure, and Glycemia in African Americans

CONTEXT

Armadillo repeat containing 5 (ARMC5) on chromosome 16 is an adrenal gland tumor suppressor gene associated with primary aldosteronism, especially among African Americans (AAs). We examined the association of ARMC5 variants with aldosterone, plasma renin activity (PRA), blood pressure, glucose, and glycosylated hemoglobin A1c (HbA1c) in community-dwelling AAs.

METHODS

The Jackson Heart Study is a prospective cardiovascular cohort study in AAs with baseline data collection from 2000 to 2004. Kernel machine method was used to perform a single joint test to analyze for an overall association between the phenotypes of interest (aldosterone, PRA, systolic and diastolic blood pressure [SBP, DBP], glucose, and HbA1c) and the ARMC5 single nucleotide variants (SNVs) adjusted for age, sex, BMI, and medications; followed by Baysian Lasso methodology to identify sets of SNVs in terms of associated haplotypes with specific phenotypes.

RESULTS

Among 3223 participants (62% female; mean age 55.6 (SD ± 12.8) years), the average SBP and DBP were 127 and 76 mmHg, respectively. The average fasting plasma glucose and HbA1c were 101 mg/dL and 6.0%, respectively. ARMC5 variants were associated with all 6 phenotypes. Haplotype TCGCC (ch16:31476015-31476093) was negatively associated, whereas haplotype CCCCTTGCG (ch16:31477195-31477460) was positively associated with SBP, DBP, and glucose. Haplotypes GGACG (ch16:31477790-31478013) and ACGCG (ch16:31477834-31478113) were negatively associated with aldosterone and positively associated with HbA1c and glucose, respectively. Haplotype GCGCGAGC (ch16:31471193-ch16:31473597(rs114871627) was positively associated with PRA and negatively associated with HbA1c.

CONCLUSIONS

ARMC5 variants are associated with aldosterone, PRA, blood pressure, fasting glucose, and HbA1c in community-dwelling AAs, suggesting that germline mutations in ARMC5 may underlie cardiometabolic disease in AAs.

ARMC 5 Variants and Risk of Hypertension in Blacks: MH- GRID Study

Background

We recently found that ARMC5 variants may be associated with primary aldosteronism in blacks. We investigated a cohort from the MH‐GRID (Minority Health Genomics and Translational Research Bio‐Repository Database) and tested the association between ARMC5 variants and blood pressure in blacks.

Methods and Results

Whole exome sequencing data of 1377 blacks were analyzed. Target single‐variant and gene‐based association analyses of hypertension were performed for ARMC5, and replicated in a subset of 3015 individuals of African descent from the UK Biobank cohort. Sixteen rare variants were significantly associated with hypertension (P=0.0402) in the gene‐based (optimized sequenced kernel association test) analysis; the 16 and one other, rs116201073, together, showed a strong association (P=0.0003) with blood pressure in this data set. The presence of the rs116201073 variant was associated with lower blood pressure. We then used human embryonic kidney 293 and adrenocortical H295R cells transfected with an ARMC5 construct containing rs116201073 (c.*920T>C). The latter was common in both the discovery (MH‐GRID) and replication (UK Biobank) data and reached statistical significance (P=0.044 [odds ratio, 0.7] and P=0.007 [odds ratio, 0.76], respectively). The allele carrying rs116201073 increased levels of ARMC5 mRNA, consistent with its protective effect in the epidemiological data.

Conclusions

ARMC5 shows an association with hypertension in blacks when rare variants within the gene are considered. We also identified a protective variant of the ARMC5 gene with an effect on ARMC5 expression confirmed in vitro. These results extend our previous report of ARMC5’s possible involvement in the determination of blood pressure in blacks.