Cardiovascular hypertrophy does not predispose to genetic hypertension

Area of Science:

• Cardiovascular Physiology
• Hypertension Research
• Genetics

Background:

• Genetic hypertension is a complex trait with multifactorial origins.
• A prevailing hypothesis suggests that cardiovascular structural changes, like hypertrophy, may precede and contribute to hypertension development.
• Investigating early structural markers could identify susceptibility to genetic hypertension.

Purpose of the Study:

• To determine if cardiovascular structural abnormalities in youth are associated with susceptibility to genetic hypertension.
• To test the hypothesis that cardiac and vascular hypertrophy precede and contribute to the development of genetic hypertension.

Main Methods:

• Utilized F2 rats from a cross between spontaneously hypertensive rats (SHR) and normotensive Donryu (DRY) rats.
• Assessed left ventricular mass (LVM) via echocardiography and mesenteric resistance vessel media-lumen ratio (MLR) at 9 weeks of age.
• Measured direct mean arterial pressure at 20 weeks of age in the same cohort.

Main Results:

• The range of LVM and MLR in young F2 rats mirrored that of SHR and DRY at the same age.
• No significant correlation was found between LVM or MLR in youth and subsequent blood pressure levels at 20 weeks.
• F2 rats exhibiting cardiovascular structural phenotypes within the SHR range did not show higher blood pressure than the general F2 population.

Conclusions:

• These findings do not support the hypothesis that cardiac hypertrophy or mesenteric resistance vessel hypertrophy confer susceptibility to genetic hypertension.
• Early cardiovascular structural abnormalities, as measured, are not predictive of hypertension development in this genetic model.
• The study suggests that other factors likely play a more significant role in the pathogenesis of genetic hypertension.