Relationship between plasma calcineurin level and echocardiographic parameters of left ventricular diastolic function

AIM To investigate the relationship between plasma calcineurin level and echocardiographic parameters of left ventricular diastolic function. METHODS Plasma calcineurin and NT-proBNP levels were determined by ELISA assay in 15 male spontaneously hypertensive rats (SHR) and 15 six month old Wistar rats, cardiac diastolic and systolic functions were assessed by high resolution echocardiography with a 17.5 MHz probe. The relationships between plasma calcineurin and diastolic echocardiographic parameters were analyzed by correlation analysis and multiple linear regression analysis. RESULTS Compared to six-month-old Wistar rats, systolic blood pressure of SHR was higher than 140 mmHg ［(114±10) mmHg vs.(186±14) mmHg, P<0.01］. Plasma calcineurin and NT-proBNP levels both increased in SHR than those in Wistar rats ［(2.1±0.5) ng/ml vs.(1.2±0.4) ng/ml, P<0.01; (327±86) fmol/ml vs.(229±85) fmol/ml, P<0.01］. Further, E/A ratio and E′/A′ ratio significantly decreased in the SHR group compared with those of the Wistar rats (1.9±0.6 vs. 2.5±0.4 for E/A, 0.82±0.47 vs. 1.39±0.17 for E′/A′, both P<0.01). In a multiple linear regression model including body weight, systolic blood pressure, heart rate, ejection fraction, plasma NT-proBNP level, E/A, E′/A′, E/E′, deceleration time and isovolumic relaxation time, plasma NT-proBNP level, E/A and E′/A′ were independent variables of plasma calcineurin level (standardized coefficient=0.003, P<0.01; standardized coefficient=-0.354, P<0.01; standardized coefficient=-0.135, P<0.05, respectively). Linear correlation analysis showed plasma calcineurin level positively correlated with body weight, systolic blood pressure, plasma NT-proBNP level and isovolumic relaxation time (r=0.688, P<0.01; r=0.758, P<0.01; r=0.983, P<0.01; r=0.577, P<0.05, respectively). Plasma calcineurin level negatively correlated with E/A and E′/A′ (r=-0.977, P<0.01; r=-0.929, P<0.01), while there were no correlations between plasma calcineurin level and heart rate, ejection fraction, E/E′ as well as deceleration time. CONCLUSION Plasma calcineurin level in SHR is higher than that in Wistar rats and correlated well with diastolic echocardiographic parameters, suggesting plasma calcineurin level may be a useful biomarker for assessing left ventricular diastolic dysfunction.