Ca²⁺-sensitivity of active force, and passive force in PDE5-TG and WT cardiac myocytes after chronic pressure overload.

<p>(<b>A</b>) In the Ca²⁺-force relationship, the Ca²⁺-sensitivity of isometric force production represents the [Ca²⁺] (plotted as a function of pCa; pCa = −log₁₀[Ca²⁺]) evoking half-maximal force production (<i>top panel</i>). Ca²⁺-sensitivity did not differ between PDE5-TG and WT cardiac myocytes, and was reduced after pretreatment with PKG (<i>bottom panel</i>). (<b>B</b>) Passive forces were significantly greater in cardiac myocytes from PDE5-TG compared to WT cardiac myocytes. Pretreatment of cardiac myocytes with PKG significantly reduced the passive forces in both genotypes. *<i>P</i><0.05; ^†<i>P</i><0.05 vs without PKG.</p

Hemodynamic parameters in PDE5-TG and WT after 10 weeks TAC.

<p>HW/BW indicates heart to body weight ratio; RCA-LCA gradient, gradient between right and left common carotid artery; dP/dt_max and dP/dt_min, maximum and minimum of the first derivative of LV pressure over time; Tau, time constant for isovolumic relaxation (Weiss); and HR, heart rate. *<i>P</i><0.05 vs WT.</p

PDE5 expression in cardiac tissue from mice with chronic pressure overload.

<p>(<b>A</b>) Immunoblot analysis showed increased PDE5 protein expression after chronic pressure overload. Protein levels of GAPDH were measured to control for sample variability. (<b>B</b>) Immunohistochemical staining of PDE5 demonstrated that increased PDE5 expression was present in cardiac myocytes. Colocalization was confirmed in confocal images of double immunofluorescent staining of PDE5 (green) and desmin (red). Scale bars, 20 µm.</p

Indices of cardiac remodeling after 10 weeks TAC in WT mice with increased PDE5 expression.

<p>HW/BW indicates heart to body weight ratio; LVID_D, LV internal diameter during diastole; EDV, end-diastolic volume; LVID_S, LV internal diameter during systole; ESV, end-systolic volume; FS, fractional shortening; EF, ejection fraction; and HR, heart rate. <b>^†</b><i>P</i><0.05 vs baseline, ^*<i>P</i><0.05 vs mice with moderately increased PDE5 expression.</p

PDE5 expression in LV outflow tract tissue from patients with severe aortic stenosis.

<p>(<b>A</b>) In cardiac tissue of control subjects, PDE5 expression was limited. In contrast, in AS patients, marked PDE5 immunoreactivity was present in scattered cardiac myocytes. (<b>B</b>) Double immunofluorescent staining of PDE5 (green) and desmin (red) confirmed protein expression in cardiac myocytes. Scale bars, 25 µm.</p

Myocardial levels of SERCA2 in PDE5-TG and WT after 10 weeks TAC.

<p>Transcript levels (<b>A</b>) and protein levels (<b>B</b>) of SERCA2, measured using RT-qPCR and immunoblot and densitometric analysis, respectively, were significantly lower in PDE5-TG than in WT. Transcript and protein levels of GAPDH were measured for normalization. ^*<i>P</i><0.05 vs WT.</p