Role of nitric oxide, tetrahydrobiopterin and peroxynitrite in glucose toxicity-associated contractile dysfunction in ventricular myocytes

Diabetologia. 2003 Oct;46(10):1419-27. doi: 10.1007/s00125-003-1183-8. Epub 2003 Jul 29.

Abstract

Aims/hypothesis: Local overproduction of nitric oxide is seen in early stages of diabetes, which can react with superoxide (O(2)(-)) to form peroxynitrite (ONOO(-)). The aim of this study was to examine the effect of scavengers for nitric oxide, O(2)(-), ONOO(-) and NOS cofactor tetrahydrobiopterin (BH(4)) on high glucose-induced cardiac contractile dysfunction.

Methods: Ventricular myocytes were cultured for 24 h with either normal (N, 5.5 mmol/l) or high (25.5 mmol/l) glucose, with or without the nitric oxide scavengers haemoglobin (100 nmol/l), PTIO (100 micromol/l), the NOS inhibitor L-NMMA (100 micromol/l), superoxide dismutase (SOD, 500 U/ml), the ONOO(-) scavengers urate (100 micromol/l), MnTABP (100 micromol/l), BH(4) (10 micromol/l) and its inactive analogue NH(4) (10 micromol/l), and the GTP cyclohydrolase I inhibitor DAHP (1 mmol/l). Myocyte mechanics, NOS protein expression and activity were evaluated.

Results: High glucose myocytes showed reduced peak shortening, decreased maximal velocity of shortening/relengthening (+/- dL/dt), prolonged relengthening (TR(90)) and normal shortening duration (TPS) associated with reduced cytosolic Ca(2+) rise compared to normal myocytes. The high glucose-induced abnormalities were abrogated or attenuated by urate, MnTBAP, L-NMMA, BH(4), and SOD, whereas unaffected by haemoglobin, PTIO and NH(4). L-NMMA reduced peak shortening while PTIO and DAHP depressed +/- dL/dt and prolonged TPS or TR(90) in normal myocytes. High glucose increased NOS activity, protein expression of eNOS but not iNOS, which were attenuated by L-NMMA and BH(4), respectively.

Conclusion/interpretation: These results suggested that NOS cofactor, NO and ONOO(-) play a role in glucose-induced cardiomyocyte contractile dysfunction and in the pathogenesis of diabetic cardiomyopathy.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Biopterin / analogs & derivatives*
  • Biopterin / metabolism*
  • Calcium / metabolism
  • Cells, Cultured
  • Enzyme Inhibitors / pharmacology
  • Free Radical Scavengers / pharmacology
  • Glucose / poisoning*
  • Intracellular Membranes / metabolism
  • Male
  • Myocardial Contraction / drug effects*
  • Myocytes, Cardiac / drug effects
  • Myocytes, Cardiac / metabolism
  • Nitric Oxide / metabolism*
  • Nitric Oxide Synthase / antagonists & inhibitors
  • Nitric Oxide Synthase / metabolism
  • Peroxynitrous Acid / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Superoxide Dismutase / pharmacology
  • Ventricular Dysfunction / metabolism
  • Ventricular Dysfunction / physiopathology*
  • omega-N-Methylarginine / pharmacology

Substances

  • Enzyme Inhibitors
  • Free Radical Scavengers
  • Peroxynitrous Acid
  • Biopterin
  • omega-N-Methylarginine
  • Nitric Oxide
  • Nitric Oxide Synthase
  • Superoxide Dismutase
  • sapropterin
  • Glucose
  • Calcium