title: Quantification of systemic renin-angiotensin system peptides of hypertensive black and white African men established from the RAS-Fingerprint®.
abstract: OBJECTIVE
  The objective of this study was to make use of a quantitative and qualitative approach comparing the systemic renin-angiotensin system (RAS) of hypertensive black and white African men by using RAS equilibrium analysis.
  
  
  METHODS
  This sub-study involved 23 black (n = 15) and white (n = 8) hypertensive men aged 39.5-41 years, living in the North West Province of South Africa. The RAS-Fingerprinting was determined with LC-MS/MS quantification of angiotensin peptides. Blood pressure and other variables were determined with known methods.
  
  
  RESULTS
  The main finding of this study was the significant lower Ang I (<5.0 and 45.1 pg/ml; p = 0.005) and Ang II (15.6 and 123.9 pg/ml; p ⩽ 0.001) encountered in the hypertensive black African men compared to their white counterparts. Levels of Ang 1-5 (downstream metabolite of Ang 1-7) (1.8 and 3.0 pg/ml), were detected in black and white hypertensive men, respectively.
  
  
  CONCLUSIONS
  The observed differences between circulating RAS components, which are reflected via equilibrium angiotensin levels, point to a distinctive molecular regulation of the RAAS in the two study cohorts. The increased peripheral resistance observed in hypertensive black individuals might take over a dominant role in control of blood pressure in this study population. A novel highly sensitive LC-MS/MS method resolved the issue of peptide recovery variations during sample preparation by using internal standards for each individual angiotensin metabolite.
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom campus, South Africa johannes.vanrooyen@nwu.ac.za.
authors.forename: J M
authors.initials: JM
authors.lastname: van Rooyen
authors.affiliation: Attoquant Diagnostics, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Poglitsch
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom campus, South Africa.
authors.forename: H W
authors.initials: HW
authors.lastname: Huisman
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom campus, South Africa.
authors.forename: Cmc
authors.initials: C
authors.lastname: Mels
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom campus, South Africa.
authors.forename: R
authors.initials: R
authors.lastname: Kruger
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom campus, South Africa.
authors.forename: L
authors.initials: L
authors.lastname: Malan
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom campus, South Africa.
authors.forename: S
authors.initials: S
authors.lastname: Botha
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom campus, South Africa.
authors.forename: L
authors.initials: L
authors.lastname: Lammertyn
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom campus, South Africa.
authors.forename: L
authors.initials: L
authors.lastname: Gafane
authors.affiliation: Hypertension in Africa Research Team (HART), North-West University, Potchefstroom campus, South Africa MRC Extra Mural Unit: Hypertension and Cardiovascular Disease, North-West University, South Africa.
authors.forename: A E
authors.initials: AE
authors.lastname: Schutte
mesh_terms: D000328:Adult; D000804:Angiotensin II / Q000097:blood; D044383:Black People; D006801:Humans; D006973:Hypertension / Q000097:blood*; D008297:Male; D010455:Peptides / Q000097:blood*; D012084:Renin-Angiotensin System; D018709:Statistics, Nonparametric; D044465:White People
chemical_list: D010455:Peptides; D000804:Angiotensin II
keywords: RAS peptides; RAS-Fingerprint; blacks; renin; whites