Glomerular hemodynamics in severe obesity

Avry Chagnac, Talia Weinstein, Asher Korzets, Edward Ramadan, Judith Hirsch, Uzi Gafter

Research output: Contribution to journalArticlepeer-review

Abstract

Differential solute clearances were used to characterize glomerular function in 12 nondiabetic subjects with severe obesity (body mass index >38). Nine healthy subjects served as the control group. In the obese group, glomerular filtration rate (GFR) and renal plasma flow (RPF) exceeded the control value by 51 and 31%, respectively. Consequently, filtration fraction increased. The augmented RPF suggested a state of renal vasodilatation involving, mainly or solely, the afferent arteriole. Albumin excretion rate and fractional albumin clearance increased by 89 and 78%, respectively. Oral glucose tolerance tests were suggestive of insulin resistance. Insulin resistance was positively correlated with GFR (r = 0.88, P < 0.001) and RPF (r = 0.72, P < 0.001). Mean arterial pressure was higher than in the control group. Fractional clearances of dextrans of broad size distribution tended to be lowered. The determinants of the GFR were estimated qualitatively by using a theoretical model of dextran transport through a heteroporous membrane. This analysis suggests that the high GFR in very obese subjects may be the result of an increase in transcapillary hydraulic pressure difference (ΔP). An abnormal transmission of increased arterial pressure to the glomerular capillaries through a dilated afferent arteriole could account for the augmentation in ΔP.

Original languageEnglish
Pages (from-to)F817-F822
JournalAmerican Journal of Physiology - Renal Physiology
Volume278
Issue number5 47-5
DOIs
StatePublished - May 2000
Externally publishedYes

Keywords

  • Dextran
  • Glomerular barrier
  • Hyperfiltration
  • Insulin resistance
  • Transcapillary hydraulic pressure difference

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