Albumin-bound fatty acids induce mitochondrial oxidant stress and impair antioxidant responses in proximal tubular cells

Kidney Int. 2006 Aug;70(4):724-31. doi: 10.1038/ Epub 2006 Jul 12.


Albumin induces oxidative stress and cytokine production in proximal tubular cells (PTECs). Albumin-bound fatty acids (FAs) enhance tubulopathic effects of albumin in vivo. We proposed that FA aggravation of albumin-induced oxidative stress in PTECs might be involved. We hypothesized that mitochondria could be a source of such stress. Using a fluorescent probe, we compared reactive oxygen species (ROS) production after exposure of PTECs to bovine serum albumin (BSA) alone or loaded with oleic acid (OA-BSA) (3-30 g/l for 2 h). There was no difference in cellular albumin uptake, but OA-BSA dose-dependently induced more ROS than BSA alone (P<0.001). OA-BSA-induced ROS was significantly alleviated by mitochondrial inhibition, but not by inhibitors of nicotinamide adenine dinucleotide phosphate hydrogenase (NADPH) oxidase, xanthine oxidase, or nitric oxide synthase. Gene expression analysis showed that neither the NADPH oxidase component p22phox nor xanthine oxidase was induced by BSA or OA-BSA. OA-BSA, in contrast to BSA, failed to induce mitochondrial manganese superoxide dismutase 2 (SOD2) expression. OA-BSA showed a greater capacity than BSA to downregulate heme oxygenase-1 mRNA expression and accentuate inflammatory cytokine mRNA and protein. Supplementation of SOD activity with EUK-8 reduced ROS, and interleukin-6 protein expression was suppressed by both mitochondrial inhibition and SOD augmentation. Thus, in PTECs, FAs accentuate albumin-induced oxidative stress and inflammatory cytokine expression via increased mitochondrial ROS, while frustrating protective antioxidant responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Albumins / physiology*
  • Cells, Cultured
  • Ethylenediamines / pharmacology
  • Fatty Acids / physiology*
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / physiology
  • Heme Oxygenase-1 / metabolism
  • Humans
  • Interleukin-6 / metabolism
  • Kidney Tubules, Proximal / drug effects*
  • Kidney Tubules, Proximal / metabolism
  • Kidney Tubules, Proximal / physiopathology
  • Mitochondria / drug effects*
  • Mitochondria / metabolism
  • NADPH Oxidases / metabolism
  • Oleic Acid / pharmacology
  • Organometallic Compounds / pharmacology
  • Oxidative Stress / drug effects*
  • RNA, Messenger / metabolism
  • Reactive Oxygen Species / metabolism*
  • Serum Albumin, Bovine / pharmacology
  • Superoxide Dismutase / metabolism
  • Xanthine Oxidase / metabolism


  • Albumins
  • Ethylenediamines
  • Fatty Acids
  • Interleukin-6
  • Organometallic Compounds
  • RNA, Messenger
  • Reactive Oxygen Species
  • Serum Albumin, Bovine
  • Oleic Acid
  • N,N'-bis(salicylideneamino)ethane-manganese(II)
  • HMOX1 protein, human
  • Heme Oxygenase-1
  • Superoxide Dismutase
  • superoxide dismutase 2
  • Xanthine Oxidase
  • NADPH Oxidases
  • CYBA protein, human