Glomerular hyperfiltration during sympathetic nervous system activation in early essential hypertension

Area of Science:

• Nephrology
• Cardiovascular Physiology
• Hypertension Research

Background:

• Glomerular hyperfiltration is implicated in essential hypertension development.
• Renin-angiotensin and sympathetic nervous systems regulate renal hemodynamics.

Purpose of the Study:

• To investigate if sympathetic nervous system activation unmasks glomerular hyperfiltration in early essential hypertension.
• To examine renal hemodynamics and renin-angiotensin system activity during mental stress.

Main Methods:

• Assessed glomerular filtration rate (GFR) and renal plasma flow (RPF) using inulin and para-aminohippuric acid clearance.
• Measured hemodynamics and plasma renin activity, Angiotensin II, and aldosterone at rest and during mental stress.
• Utilized angiotensin-converting enzyme inhibitor to assess renin-angiotensin system blockade.

Main Results:

• At rest, no significant differences in renal hemodynamics or renin-angiotensin system activity were observed between normotensive and hypertensive subjects.
• Mental stress increased blood pressure similarly in both groups but caused a greater increase in GFR and filtration fraction in hypertensive subjects.
• Increased GFR during stress correlated with elevated Angiotensin II levels, and ACE inhibition attenuated this increase in hypertensive individuals.

Conclusions:

• Glomerular hyperfiltration is evident during sympathetic nervous system activation in early essential hypertension.
• This stress-induced hyperfiltration is mediated by postglomerular vasoconstriction and influenced by the renin-angiotensin system.
• Early, stress-induced glomerular hyperfiltration may be a contributing factor or trigger for essential hypertension.