Exploring the Link Between Cardiovascular Reactivity and End-Organ Damage in African and Caucasian Men: The SABPA Study

Huisman, Hugo W.; Schutte, Aletta E.; Schutte, Rudolph; Rooyen, Johannes M. Van; Fourie, C.M.T.; Mels, Catharina M C; Smith, Wayne; Malan, Nicolaas T.; Malan, Leoné

doi:10.1093/ajh/hps007

Cited by 26 publications

(20 citation statements)

References 39 publications

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“…However, downregulated β-adrenergic receptor responsiveness may predispose African-Americans to a predominance of α-adrenergic receptor-mediated vasoconstriction. This racial difference in relative α 1 and β-adrenergic receptor responsiveness is exacerbated in the context of HBP and likely contributes to the elevated systemic vascular resistance that is often characteristic of hypertension among African-Americans [45,46]. This pattern of racial differences in α 1 and β-adrenergic receptor responsiveness may help to inform clinical decision-making in the optimal management of HBP.…”

Section: Discussionmentioning

confidence: 99%

Race and sex differences in cardiovascular α-adrenergic and β-adrenergic receptor responsiveness in men and women with high blood pressure

Sherwood

Hill

Blumenthal

et al. 2017

Journal of Hypertension

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Objective Hypertension is associated with unfavorable changes in adrenergic receptor responsiveness, but the relationship of race and sex to adrenergic receptor responsiveness in the development of cardiovascular disease is unclear. This study examined α-adrenergic and β-adrenergic receptor responsiveness in African-American and white men and women with untreated high blood pressure (BP) (HBP) and with normal BP. Methods and results The study sample comprised 161 African-American and white men and women in the age range 25–45 years. Isoproterenol, a nonselective β-adrenergic receptor agonist, was administered intravenously to determine the bolus dose required to increase heart rate by 25 bpm, an index of β-adrenergic receptor responsiveness. Similarly, phenylephrine, an α1-adrenergic receptor agonist, was administered to determine the bolus dose required to increase BP by 25 mmHg, an index of vascular α1-adrenergic receptor responsiveness. HBP (P <0.01), male sex (P =0.04), and higher BMI (P <0.01) were all associated with reduced β-adrenergic receptor responsiveness, with a similar trend observed for African-American race (P =0.07). Conversely, α1-adrenergic receptor responsiveness was increased in association with HBP (P <0.01), female sex (P <0.01), and African-American race (P <0.01). Conclusion In the early stages of hypertension, cardiovascular β-adrenergic receptors demonstrate blunted responsiveness, whereas conversely α1-adrenergic receptors exhibit increased responsiveness. This pattern of receptor changes is especially evident in men and African-Americans, is exacerbated by obesity, and may contribute to the development of cardiovascular disease.

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Section: Discussionmentioning

confidence: 99%

Race and sex differences in cardiovascular α-adrenergic and β-adrenergic receptor responsiveness in men and women with high blood pressure

Sherwood

Hill

Blumenthal

et al. 2017

Journal of Hypertension

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“…This higher level of arterial stiffness was accompanied with increased levels of DBP and CRP in men with low BMI. Increased vascular resistance could at least partly contribute to the increased DBP, while inflammation can be associated with CRP ( 33 ) . This suggests detrimental changes in vascular and endothelial functions in men with low BMI.…”

Section: Discussionmentioning

confidence: 99%

Low BMI is inversely associated with arterial stiffness in Africans

et al. 2015

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In low socio-economic status communities in South Africa, African men showed a low BMI. Data on the effect of low BMI on cardiovascular function are scant. The present study aimed to assess the associations between low BMI and markers of cardiovascular function such as pulse wave velocity (PWV) and blood pressure in Africans aged 35 -65 years, with low socio-economic status. The study population (n 496) was stratified into a low-BMI group with BMI # 20 kg/m 2 and a normal-BMI group with BMI .20 kg/m 2 and #25 kg/m 2 . Blood pressure (Omron HEM-757) and PWV (Complior SP; Artech-Medical) was determined. Africans with low BMI showed an increased arterial stiffness with significantly higher PWV compared with the normal-BMI group (men: P¼ 0·001; women: P¼0·026), which remained after adjustment. In men with low BMI, PWV correlated negatively with BMI before (r 20·204; P¼0·012) and after (r 2 0·200; P¼ 0·020) adjustment. Forward stepwise regression analyses indicated a negative association between PWV and BMI in African men. A J-curve was evident suggesting a detrimental effect of low BMI on cardiovascular function in Africans. A low BMI may contribute to the high prevalence of cardiovascular-related morbidity and mortality within a developing country.

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“…; Huisman et al . ), but to date, no studies have been published comparing microvascular endothelial function between these ethnic groups. Given that disturbances in microvascular function have been shown to precede macrovascular disease (Gates et al .…”

Section: Introductionmentioning

confidence: 99%

“…Irrespective of the technique, multiethnic studies usually compare vascular function in healthy control subjects with subjects who have with known conditions, such as hypertension (Schutte et al 2006), heart failure (Shantsila et al 2011b) or diabetes (Strain et al 2006). In South Africa, only macrovascular function has been compared between Black African and Caucasian subjects with and without disease (Schutte et al 2006(Schutte et al , 2011Holland et al 2009;Huisman et al 2013), but to date, no studies have been published comparing microvascular endothelial function between these ethnic groups. Given that disturbances in microvascular function have been shown to precede macrovascular disease (Gates et al 2009), assessment of endothelial microvascular function may provide valuable insight into the aetiology of CVD risk disparities between ethnic groups and may therefore provide more opportunities for intervention.…”

Section: Introductionmentioning

confidence: 99%

Ethnic differences in microvascular function in apparently healthy South African men and women

Pienaar

Micklesfield

Gill

et al. 2014

Experimental Physiology

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New Findings r What is the central question of this study?It is well recognized that there are disparities in cardiovascular disease outcomes between ethnic groups. Are there ethnic differences in microvascular function between healthy, young men and women of different ethnicities? This study used laser Doppler imagery and iontophoresis of acetylcholine and sodium nitroprusside to compare microvascular function between different ethnic groups and to understand the role of skin resistance in this methodology. r What is the main finding and its importance?Endothelium-independent microvascular function remained attenuated after correcting for skin resistance in the Black African and mixed ancestry groups, suggesting that differences in smooth muscle function may be an important factor contributing to ethnic differences in disease risk.Microvascular dysfunction precedes the clinical manifestations of cardiovascular disease. Given the ethnic disparities in cardiovascular disease, we aimed to investigate ethnic differences in microvascular endothelial function in a group of young (18-33 years old), apparently healthy individuals (n = 33, nine Black African, 12 mixed ancestry and 12 Caucasian). Microvascular endothelium-dependent and -independent function was assessed by laser Doppler imagery and iontophoresis of ACh and sodium nitroprusside (SNP), respectively, adjusting for skin resistance. Microvascular reactivity was expressed as maximum absolute perfusion, percentage change from baseline and area under the curve (AUC). Skin resistance was significantly lower in the Caucasian group in response to ACh (Caucasian, mean 0.16 ± 0.03 versus Black, 0.21 ± 0.04 and mixed ancestry, 0.20 ± 0.02 , P < 0.01) and SNP (Caucasian, 0.08 ± 0.01 versus Black, 0.11 ± 0.02 and mixed ancestry, 0.12 ± 0.01 , P < 0.01). Microvascular function in response to ACh was significantly higher in the Caucasian group compared with the other two groups; however, after adjusting for skin resistance these differences were no longer significant. Conversely, the microvascular SNP response remained significantly higher in the Caucasian group, even after adjusting for skin resistance (P < 0.01).

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Exploring the Link Between Cardiovascular Reactivity and End-Organ Damage in African and Caucasian Men: The SABPA Study

Cited by 26 publications

References 39 publications

Race and sex differences in cardiovascular α-adrenergic and β-adrenergic receptor responsiveness in men and women with high blood pressure

Race and sex differences in cardiovascular α-adrenergic and β-adrenergic receptor responsiveness in men and women with high blood pressure

Low BMI is inversely associated with arterial stiffness in Africans

Ethnic differences in microvascular function in apparently healthy South African men and women

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