Association of Kidney Function and Metabolic Risk Factors With Density of Glomeruli on Renal Biopsy Samples From Living Donors

OBJECTIVE: To test the hypothesis that kidney function and metabolic risk factors are associated with giomerular density on renal biopsy samples from healthy adults. PATIENTS AND METHODS: This study compared giomerular density with predonation kidney function, blood pressure, and metabolic risk factors in living kidney donors at Mayo Clinic in Rochester, MN, from May 10, 1999, to February 4, 2009. During implantation of the kidney allograft, an 18-gauge core needle biopsy sample of the renal cortex was obtained, sectioned, and examined by pathologists. Giomerular density was determined by the number of giomeruli (normal and sclerotic) divided by area of cortex. RESULTS: The study sample of 1046 kidney donors had a mean of 21 glomeruli (0.8 sclerotic giomeruli) and a glomerular density of 2.3 giomeruli per square millimeter. In a subset of 54 donors, glomerular density inversely correlated with the mean giomerular area (r(s)=-0.28). Independent predictors of decreased glomerular density were older age, increased glomerular filtration rate, family history of end-stage renal disease, Increased serum uric acid, and Increased body mass index. Increased urine albumin excretion, hypertension, decreased high-density lipoprotein cholesterol, and metabolic syndrome were also associated with decreased glomerular density after age-sex adjustment. These associations were not explained by the presence of glomerulosclerosis, tubular atrophy, Interstitial fibrosis, or arteriosclerosis on the renal biopsy sample. In older donors, decreased giomerular density was attenuated by an increased prevalence of giomeruloscierosis and tubular atrophy. CONCLUSION: Decreased giomerular density Is associated with many different kidney function and metabolic risk factors among relatively healthy adults and may represent an early state of Increased risk of parenchymal injury.