title: Profiling of cAMP and cGMP phosphodiesterases in isolated ventricular cardiomyocytes from human hearts: comparison with rat and guinea pig.
abstract: OBJECTIVE
  Phosphodiesterases (PDEs) are key enzymes controlling cAMP and cGMP levels and spatial distribution within cardiomyocytes. Despite the clinical importance of several classes of PDE inhibitor there has not been a complete characterization of the PDE profile within the human cardiomyocyte, and no attempt to assess which species might best be used to model this for drug evaluation in heart disease.
  
  
  METHODS
  Ventricular cardiomyocytes were isolated from failing human hearts of patients with various etiologies of disease, and from rat and guinea pig hearts. Expression of PDE isoforms was determined using RT-PCR. cAMP- and cGMP-PDE hydrolytic activity was determined by scintillation proximity assay, before and after treatment with PDE inhibitors for PDEs 1, 2, 3, 4, 5 and 7. Functional effects of cAMP PDEi were determined on the contraction of single human, rat and guinea pig cardiomyocytes.
  
  
  RESULTS
  The presence and activity of PDE5 were confirmed in ventricular cardiomyocytes from failing and hypertrophied human heart, as well as PDE3, with ventricle-specific results for PDE4 and a surprisingly large contribution from PDE1 for hydrolysis of both cAMP and cGMP. The total PDE activity of human cardiomyocytes, and the profile of inhibition by PDE1, 3, 4, and 5 inhibitors, was modelled well in guinea pig but not rat cardiomyocytes.
  
  
  CONCLUSIONS
  Our results provide the first full characterisation of human cardiomyocyte PDE isoforms, and suggest that guinea pig myocytes provide a better model than rat for PDE levels and activity.
authors.affiliation: Department of Cardiac Medicine, National Heart and Lung Institute, Imperial College London, UK.
authors.forename: W B
authors.initials: WB
authors.lastname: Johnson
authors.forename: S
authors.initials: S
authors.lastname: Katugampola
authors.forename: S
authors.initials: S
authors.lastname: Able
authors.forename: C
authors.initials: C
authors.lastname: Napier
authors.forename: S E
authors.initials: SE
authors.lastname: Harding
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D006168:Guinea Pigs; D006333:Heart Failure / Q000201:enzymology*; D006352:Heart Ventricles / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects; D032383:Myocytes, Cardiac / Q000201:enzymology*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D010726:Phosphodiesterase Inhibitors; D000242:Cyclic AMP; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D006152:Cyclic GMP