Time Distributions Of Cardiac Adiponectin Receptors In Spontaneously Hypertensive Rat With Progression Of Left Ventricular Diastolic Dysfunction

Background: Heart failure with preserved ejection fraction(HFPEF) has been concerned in recent years as the heart failure types. Cardiac diastolic dysfunction played an important role in the pathogenesis of HFp EF. Recently, it’s found to the occurrence of diastolic dysfunction closely related with reduce of the adiponectin(APN) levels. APN belongs to adipokines that mainly secreted from white adipocytes and through various channels and mechanisms played a role of protection of diastolic dysfunction. APN plays cardioprotective roles through activating its receptors(Adipo R1, Adipo R2, T-cadherin), however the time distributions of APN receptors in left ventricular diastolic dysfunction remains to be clarified.Objective: To observe the changes of three cardiac APN receptors during the progression of cardiac diastolic dysfunction in spontaneously hypertensive rat(SHR).Methods: 24 male SHR and age-matched Wistar rats of 3-month-old were examined every 3 months till 12 months old(6 rats for each group). Systolic blood pressure(SBP) and heart rate were measured by a tail-cuff method, cardiac structure and function were performed using echocardiography, myocardial hematoxylin-eosin(HE) staining for cardiomyocytes size or massion staining to count myocardial fibrotic area, serum NT-pro BNP levels and APN concentrations were measured by ELISA. The expressions of APN receptors were determined by Western blotting.Results: Compared with age-matched Wistar rats, SHR at 6-month-old emerged cardiac diastolic dysfunction as evidenced by decreased E/A ratio(2.01±0.22 vs 2.74±0.15, P<0,01) and E’/A’ ratio(0.95±0.26 vs 1.35±0.32, P<0,01), increased E/E’ ratio(28.41±1.76 vs 20.66±2.37, P<0,01) as well as elevated serum NT-pro BNP level(2.491±0.22ng/ml vs 1.969±0.59ng/ml, P<0,01). Both the myocardial level and serum APN level decreased gradually with increasing time. The expression of Adipo R1 remained unchanged from 3 months to 9 months, began to decrease at 12 months. T-cadherin began to decrease at 6 months and then remained the level till 12 months, while Adipo R2 levels remained the same level in the whole course.Conclusions: Different APN receptors presented diverse time distributions in SHR with the progression of cardiac diastolic dysfunction. T-cadherin declined at the presence of cardiac diastolic dysfunction, and Adipo R1 decreased with severe cardiac diastolic dysfunction, while Adipo R2 remained unchanged.