CCN2/CTGF attenuates myocardial hypertrophy and cardiac dysfunction upon chronic pressure-overload

Background

Myocardial CCN2/CTGF (connective tissue growth factor) is strongly induced in heart failure (HF) and acts as a cardioprotective factor in ischemia/reperfusion injury. However, its functional role in myocardial hypertrophy remains unresolved.

Methods and results

Transgenic mice with cardiac-restricted overexpression of CTGF (Tg-CTGF) and non-transgenic littermate control (NLC) mice were subjected to chronic pressure-overload by abdominal aortic banding. After 4 weeks of persistent pressure-overload, a time point at which compensatory hypertrophy of the left ventricle (LV) prevails, Tg-CTGF mice displayed diminished increase of LV mass compared with NLC. At study end-point after 12 weeks of sustained aortic constriction, the mice displayed LV dilatation and reduced cardiac function. Repeated transthoracic echocardiography during the 12 weeks of chronic pressure-overload, revealed attenuation of LV dilatation and virtually sustained systolic function in Tg-CTGF mice compared with NLC mice. Also, increase of LV mass was blunted in Tg-CTGF versus NLC mice at study end-point. Consistently, increases of myocardial ANP, BNP and skeletal α-actin mRNA levels were blunted in Tg-CTGF mice subjected to chronic pressure-overload. Furthermore, cardiac myocytes from Tg-CTGF mice displayed increased phospho-NFATc2 levels and attenuated hypertrophic response upon stimulation with α₁-adrenoceptor agonist, indicating that CTGF attenuates hypertrophic signaling in cardiac myocytes. Increase of myocardial collagen contents in mice subjected to aortic banding was similar in Tg-CTGF and NLC mice, indicating that CTGF have minimal impact on myocardial collagen deposition.

Conclusion

This study provides novel evidence that CTGF attenuates cardiac hypertrophy upon chronic pressure-overload due to inhibition of signaling mechanisms that promote pathologic myocardial hypertrophy.