Abstract: TH-PO559

Racial Differences in Nephron Number, Role of Body Size, Kidney Weight, and Cortical Volume in Adult Subjects among Five Populations

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 301 CKD: Risk Factors for Incidence and Progression

Authors

  • Kanzaki, Go, Monash University, Melbourne, Australia
  • Puelles, Victor G., University Hospital RWTH Aachen, Aachen, Germany
  • Cullen-McEwen, Luise A., Monash University, Melbourne, Victoria, Australia
  • Hoy, Wendy E., The University of Queensland, Brisbane, Queensland, Australia
  • Okabayashi, Yusuke, The Jikei University School of Medicine, Tokyo, Japan
  • Tsuboi, Nobuo, The Jikei University School of Medicine, Tokyo, Japan
  • Shimizu, Akira, Nippion Medical School, Tokyo, Japan
  • Yokoo, Takashi, The Jikei University School of Medicine, Tokyo, Japan
  • Bertram, John F., Monash University, Melbourne, Victoria, Australia
Background

Nephron number in normal adult kidneys varies widely and is influenced by birth weight, age and race. Our recent studies have shown that Aboriginal and Japanese subjects have fewer nephrons than most populations studied to date and they are at high-risk for CKD. However, the cause of these racial differences in nephron number is not fully elucidated. In this study, we examined the effects of body size, kidney weight, and cortical volume on nephron number among races.

Methods

We analysed kidneys at autopsy from subjects aged 20-65 years without overt kidney disease in Aboriginal Australians (n=16), Japanese (n=12), Caucasian Americans (n=79), African Americans (n=65), and Senegalese (n=36). Total nephron number (Nglom) was estimated by design-based stereology. Cortical volume was calculated by Cavalieri Principle.

Results

Nglom per kidney in Aboriginal Australians (730,523±224,460; mean±SD) and Japanese subjects (716,236±185,767) was significantly lower than in Caucasian Americans (974,940±304,731), African Americans (943,446±276,017) and Senegalese (982,450±276,210). Although this difference was still present after adjustment for height or kidney weight, Nglom after adjustment for BMI, BSA, or cortical volume was similar in the five populations.

Conclusion

This study shows there is no difference in nephron number among the five races after adjustment for body size or cortical volume. It indicates that while Aboriginal and Japanese subjects with smaller body size have fewer nephrons than the other races, further nephron loss and/or increased body size would likely increase the risk of CKD.

Nephron number in 20-65 years old subjects among five populations
 AboriginalJapaneseCaucasian AmericansAfrican AmericansSenegaleseANOVA (P value)
N1612796536 
Nglom730,523±224,460716,236±185,767974,940±304,731953,446±276,017982,450±276,2100.0016
Nglom/Ht (/m)437,159±136,925427,795±111,339579,028±178,574555,577±154,286583,028±165,9310.0018
Nglom (/m2)454,593±148,486440,301±130,080500,791±167,970476,932±134,520544,714±165,8810.1305
Nglom/BMI (/kg/m2)36,795±13,02233,819±11,84335,085±13,68634,609±12,74740,691±13,2290.2016
Nglom/Kwt (/g)4,798±1,7544,141±1,4975,826±2,1786,132±2,0017,266±2,210<0.0001
Nglom/Vcort (/cm3)6,417±1,5066,963±1,9027,650±2,3427,777±2,2098,152±2,1170.0889

mean±SD