February 1, 1996Journal of Hypertension
Blunted renal vascular response to angiotensin II is associated with a common variant of the angiotensinogen gene and obesity
Key result
Participants homozygous for the AGT T235 variant had significantly diminished renal plasma flow responses to Angiotensin II infusion (P=0.005), an effect further blunted by obesity (P=0.017).
Why the study?
Does the AGT T235 genotype and obesity affect the renal vascular response to infused Angiotensin II in humans?
Population
120 participants aged 18-60 years, including 34 hypertensive individuals off medication, 57 normotensive…
Comparison
Angiotensin II infusion at a mildly pressor dose vs Comparison by AGT genotype and obesity status
Design
Cross-sectional
Authors
Discussion
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Implication
AGT T235 homozygosity associates with blunted renal Ang II response, worsened by obesity; hypothesis-generating and should not yet change practice.
Key Points
- This research investigates how a common variant of the angiotensinogen gene affects kidney blood flow in response to angiotensin II, particularly in the context of hypertension and obesity.
- Studied 120 participants, including hypertensive and normotensive individuals, after controlled sodium diets.
- Infused Ang II at a dose of 3 ng/kg/min and measured renal plasma flow.
- Performed multivariate analyses to account for covariates.
- T235 homozygous participants had reduced renal plasma flow responses to Ang II infusion (P = 0.005).
- Renal arterial resistance changes were also blunted in T235 homozygotes.
- Obesity significantly amplified the blunted response to Ang II in T235 homozygotes (P = 0.017).
Study Design
Type
Cross-Sectional (n=120)
Structured PICO
Does the AGT T235 genotype and obesity affect the renal vascular response to infused Angiotensin II in humans?
P
Population
120 hypertensive and normotensive individuals, aged 18-60 years, studied after a controlled sodium diet to assess renal vascular response to infused Angiotensin II.
E
Exposure
Angiotensin II infusion at a mildly pressor dose (3 ng/kg/min)
C
Comparator
Comparison by AGT genotype (T235 homozygotes vs. other genotypes) and obesity status
O
Outcome
Renal plasma flow response to Angiotensin II infusion (determined by steady-state plasma para-aminohippurate concentration)surrogate
Main Result
p-value: p=0.005
The AGT T235 genotype is associated with a blunted renal vascular response to Angiotensin II, an effect exacerbated by obesity, providing a physiological link to essential hypertension.
Cite This Study
Hopkins et al. (1996) conducted a cross-sectional in Essential hypertension (n=120). AGT T235 homozygous genotype vs. Other AGT genotypes was evaluated on Renal plasma flow response to Angiotensin II infusion (p=0.005). Participants homozygous for the AGT T235 variant had significantly diminished renal plasma flow responses to Angiotensin II infusion (P=0.005), an effect further blunted by obesity (P=0.017).