Plasma Volume and Arterial Stiffness in the Cardiac Alterations Associated With Long-Term High Sodium Feeding in Rats

International audienceBACKGROUND: Rats fed an early and long-term high-salt diet (HS, NaCl 8%) developed significant cardiovascular hypertrophy without major changes in blood pressure. The mechanism of this cardiac hypertrophy has not been yet elucidated. METHODS: In the present work, we assessed the influence of volume overload and arterial stiffness on the structural and functional cardiac changes induced by a high salt feeding from weaning to 5 months of age in Sprague-Dawley rats. RESULTS: Cardiac hypertrophy in HS rats was associated with clear augmentation in the size of left ventricular (LV) cardiomyocyte as compared with rats fed regular diet (NS). Echocardiography revealed a marked increase in relative wall thickness. Of note, no alteration of global and regional systolic and diastolic function was detected in HS rats. High sodium consumption was associated with a slight increase in aortic mean and pulse pressure (PP) without effect on pulse wave velocity (PWV) and elastic modulus. Plasma volume and central venous pressure were higher in HS than NS rats. Whereas plasma endothelin level was twofold higher in HS than in NS rats, LV endothelin level was similar in both groups. Treatment by the endothelin receptors blocker bosentan had no detectable effect on the changes induced by HS diet. CONCLUSIONS: High sodium intake was associated with concentric cardiac hypertrophy without change of systolic and diastolic function. Aortic rigidity was not a determinant of cardiac hypertrophy. Beside a likely direct effect of sodium on cardiovascular system the slight increase in arterial pressure and plasma volume play a role

Integrated backscatter for the in vivo quantification of supraphysiological vitamin D(3)-induced cardiovascular calcifications in rats.

peer reviewedCardiovascular calcifications are frequently found in the aging population and are independent predictors of future cardiovascular events. Integrated backscatter (IB) of ultrasound reflectivity can easily quantify calcifications. For this purpose, 30 male Wistar rats received 25,000 IU/kg/day of vitamin D(3) (group 1, n = 8), 18,800 IU/kg/day (group 2, n = 8), or injections with the vehicle only (group 3, n = 14), for 10 weeks. Echocardiographic calibrated IB (cIB) was measured and calculated at baseline and after 10 weeks, followed by ex vivo micro-CT and histopathology of the aortic valve, ascending aorta, and myocardium. After 10 weeks, the mean cIB value of the aortic valve was significantly higher for vitamin D(3)-dosed animals compared to controls. The mean cIB value of the ascending aorta and the myocardium was also significantly higher in group 1 compared to group 3. In vivo IB results were confirmed by ex vivo micro-CT and histopathology. In conclusion, IB is a non-ionizing, feasible, and reproducible tool to quantify cardiovascular calcifications in an in vivo rat model. The integration of IB in the standard echocardiographic examination for the quantification of cardiovascular calcifications could be useful for serial evaluation of treatment efficacy and for prognosis assessment