Longitudinal study of living kidney donor glomerular dynamics after nephrectomy

Area of Science:

• Nephrology
• Physiology
• Transplantation

Background:

• Over 5,000 living kidney donor nephrectomies occur annually in the US.
• Long-term glomerular dynamics in living kidney donors are not well understood.
• Early physiological changes post-nephrectomy are documented, but long-term effects require further investigation.

Purpose of the Study:

• To investigate the long-term glomerular dynamics in adult living kidney donors.
• To evaluate clinical, physiological, and radiological changes at early and late post-donation stages.
• To determine the mechanisms underlying adaptive hyperfiltration after kidney donation.

Main Methods:

• Enrolled 21 adult living kidney donors for long-term evaluation.
• Conducted clinical, physiological, and radiological assessments pre-, early post- (median 0.8 years), and late post- (median 6.3 years) donation.
• Performed morphometric analysis of glomeruli from 19 subjects and used mathematical modeling to estimate glomerular ultrafiltration coefficient (Kf).

Main Results:

• Single-kidney renal plasma flow (RPF), renocortical volume, and glomerular filtration rate (GFR) increased early post-donation and remained sustained.
• Glomerular ultrafiltration coefficient (Kf) increased early and remained constant, with a 40% elevation in single-kidney GFR attributed to increased Kf.
• Hypertension prevalence rose from 14% early to 57% late post-donation; no elevated albuminuria was observed.

Conclusions:

• Adaptive hyperfiltration post-nephrectomy results from hyperperfusion and hypertrophy of remaining glomeruli.
• The findings suggest an increase in filtration surface area (Kf) drives the enhanced GFR.
• Glomerular hypertension does not appear to develop following kidney donation.