Key result
Myocardial cAMP levels in patients with heart failure (5.8 fmol/µg) were unchanged compared to controls (4.9 fmol/µg), despite significantly reduced myocardial norepinephrine (P<0.0002).
Why the study?
Does myocardial cAMP content differ between patients with heart failure and controls?
Case-Control (n=28)
Does myocardial cAMP content differ between patients with heart failure and controls?
Absolute Event Rate: 5.8% vs 4.9%
Myocardial cAMP levels measured from endomyocardial biopsies do not differ between heart failure patients and controls, likely due to baseline adenylyl cyclase stimulation during the biopsy procedure.
Biopsy cAMP measurements may not reflect in vivo levels in heart failure; leaves open cAMP dysregulation's role pending improved assays.
Impaired production of myocardial cyclic adenosine monophosphate (cAMP) is thought to contribute to contractile dysfunction in end stage heart failure, but myocardial cAMP content has not yet been evaluated in heart failure patients in comparison with controls. We therefore measured the myocardial content of cAMP by radioimmunoassay in endomyocardial biopsies from patients in different stages of heart failure and in controls and correlated it with biochemical and functional parameters. The myocardial content of norepinephrine was determined by HPLC in the same biopsies in order to assess if the myocardium studied was affected by heart failure. Myocardial cAMP (in fmol.microgram-1 non-collagen protein) in 20 patients with heart failure (LVEF: 27 +/- 8%, cAMP: 5.8 +/- 2.0) was unchanged in comparison with eight controls (LVEF: 64 +/- 4.7%, cAMP, 4.9 +/- 2.1). In contrast, myocardial norepinephrine (in pg.microgram-1 non-collagen protein) in the same biopsies was significantly reduced in heart failure (4.0 +/- 3.0) in comparison with the same controls (11.5 +/- 3.0, P < 0.0002). Plasma cAMP in 20 heart failure patients (22.0 +/- 4.2 pmol.l-1) was not different from controls(22.0 +/- 7.8), whereas plasma norepinephrine was increased (heart failure: 460 +/- 257 pg.ml-1, controls 182 +/- 49, P < 0.001). Myocardial cAMP levels are indistinguishable from controls in human heart failure and therefore do not contribute to a further characterization of the cardiac adrenergic system in these patients. This is most likely due to the impossibility of obtaining biopsies with truly unstimulated adenylyl cyclase activity.
No takes yet. Share an insight, caveat, or question.
Regitz‐Zagrosek et al. (1994) conducted a case-control in Heart failure (n=28). Heart failure vs. Controls was evaluated on Myocardial cAMP content (fmol/microgram non-collagen protein). Myocardial cAMP levels in patients with heart failure (5.8 fmol/µg) were unchanged compared to controls (4.9 fmol/µg), despite significantly reduced myocardial norepinephrine (P<0.0002).
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: