Role of angiotensin converting enzyme genotype in sodium sensitivity in older hypertensives.
BACKGROUND
Individuals differ in their blood pressure (BP) response to changes in dietary sodium (Na+) intake. It is possible that differences in BP responses to dietary Na+ are influenced by genes.


METHODS
A total of 35 older (62.9 +/- 1.2 years) hypertensive subjects had their mean arterial blood pressure (MABP) determined after 8 days of low (20 mmol/day) and high (200 mmol/day) Na+ intake. The insertion/ deletion polymorphism of the angiotensin converting enzyme (ACE) gene was genotyped with standard polymerase chain reaction methods.


RESULTS
Of the 35 subjects, 24 were classified as sodium-sensitive (> or = 5 mm Hg increase in MABP in response to the increase in dietary Na+) and 11 were classified as sodium-resistant (<5 mm Hg increase in MABP). Those homozygous for the insertion allele of the ACE gene (insertion/insertion [II]; n = 8) had lower (P = .04) MABP responses to the increase in dietary Na+ (0 +/- 3 mm Hg) compared to heterozygotes (insertion/deletion [ID]; n = 20) (9 +/- 2 mm Hg; P = .0001) and those homozygous for the deletion allele (deletion/deletion [DD]; n = 7) (9 +/- 3 mm Hg; P = .05). The prevalence of sodium sensitivity was higher (P = .0083) in DD (71%) and ID (83%) compared to II (25%) genotype groups.


CONCLUSIONS
Based on these data in older hypertensive individuals, we conclude that the ACE gene ID and DD genotypes are associated with an increase in BP during a high Na+ diet, which is consistent with the phenotypic characteristic of sodium sensitivity.
Dengel
D R
DR
School of Kinesiology and Leisure Studies, University of Minnesota, Minneapolis 55455, USA.
Brown
M D
MD
Ferrell
R E
RE
Supiano
M A
MA
D000368:Aged; D000375:Aging / Q000235:genetics / Q000378:metabolism; D000450:Aldosterone / Q000097:blood; D001794:Blood Pressure / Q000235:genetics; D004039:Diet, Sodium-Restricted; D005260:Female; D005838:Genotype; D006801:Humans; D006973:Hypertension / Q000178:diet therapy / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D007703:Peptidyl-Dipeptidase A / Q000235:genetics* / Q000378:metabolism; D011110:Polymorphism, Genetic; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System / Q000502:physiology; D012982:Sodium, Dietary / Q000097:blood* / Q000652:urine
D012982:Sodium, Dietary; D000450:Aldosterone; D007703:Peptidyl-Dipeptidase A; D012083:Renin