[Relationship between aging and renal function: a positron emission tomographic study].

Area of Science:

• Nephrology
• Gerontology
• Nuclear Medicine

Background:

• Aging is associated with physiological changes in organ function.
• Kidney function, including blood flow and filtration, may decline with age.
• Quantifying age-related changes in kidney hemodynamics is crucial for understanding renal health.

Purpose of the Study:

• To investigate age-related changes in kidney blood volume, blood flow, and glomerular filtration rate per unit of kidney tissue.
• To quantify the decline in these parameters in older adults compared to younger individuals.

Main Methods:

• Utilized positron emission tomography (PET) with C15O, H(2)15O, and 68Ga-EDTA to measure kidney blood volume (V), blood flow (F), and glomerular filtration rate (GFR).
• Studied 19 subjects across different age groups.
• Applied regression analysis to determine age-related trends.

Main Results:

• A significant negative correlation was observed between age and kidney blood volume, blood flow, and GFR.
• The decrease in kidney blood volume with aging was less pronounced than the decrease in blood flow and GFR.
• Regression analysis indicated that by the 70s, kidney blood flow, GFR were reduced to 76%, 46%, and 55% of levels seen in the 20s, respectively.

Conclusions:

• Kidney blood volume, blood flow, and glomerular filtration rate demonstrably decline with age.
• These findings highlight significant age-related functional decrements in the kidney, particularly in blood flow and filtration capacity.