Faculty Collaboration Database

Indoxyl sulfate induces complex redox alterations in mesangial cells. Am J Physiol Renal Physiol 2006 Jun;290(6):F1551-8

Date

01/26/2006

Pubmed ID

16434574

DOI

10.1152/ajprenal.00281.2004

Scopus ID

2-s2.0-33744809267 (requires institutional sign-in at Scopus site)   106 Citations

Abstract

Indoxyl sulfate is a protein metabolite that is concentrated in the serum of patients with chronic renal insufficiency. It also is a uremic toxin that has been implicated in the progression of chronic renal disease in rodent models. We have shown previously that mesangial cell redox status is related to activation of mitogen-activated protein kinases and cell proliferation, which are factors related to glomerular damage. We used three methods to examine the ability of indoxyl sulfate to alter mesangial cell redox as a possible mechanism for its toxicity. Indoxyl sulfate increases mesangial cell reduction rate in a concentration-dependent manner as demonstrated by redox microphysiometry. Alterations occurred at concentrations as low as 100 microM, with more marked alterations occurring at higher concentrations associated with human renal failure. We demonstrated that indoxyl sulfate induces the production of intracellular reactive oxygen species (ROS) in mesangial cells (EC50 = 550 microM) by using the ROS-sensitive fluorescent dye CM-DCF. ROS generation was only partially (approximately 50%) inhibited by the NADPH oxidase inhibitor diphenylene iodinium at low (< or = 300 microM) indoxyl sulfate concentrations. Diphenylene iodinium was without effect at higher concentrations of indoxyl sulfate. We also used electron paramagnetic spin resonance spectroscopy with extracellular and intracellular spin traps to show that indoxyl sulfate increases extracellular SOD-sensitive O2-* production and intracellular hydroxyl radical production that may derive from an initial O2-* burst. These results document that indoxyl sulfate, when applied to renal mesangial cells at pathological concentrations, induces rapid and complex changes in mesangial cell redox.

Author List

Gelasco AK, Raymond JR

Author

John R. Raymond MD President, CEO, Professor in the President department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Cells, Cultured
Dimethyl Sulfoxide
Dose-Response Relationship, Drug
Electron Spin Resonance Spectroscopy
Enzyme Inhibitors
Fluorescent Dyes
Hydrogen Peroxide
Hydroxyl Radical
Indican
Male
Mesangial Cells
NADPH Oxidases
Onium Compounds
Oxidation-Reduction
Rats
Rats, Sprague-Dawley
Reactive Oxygen Species
Superoxide Dismutase
Superoxides