PS-BPB07-2: AFFERENT RENAL NERVES CONTRIBUTE TO LEFT VENTRICULAR DYSFUNCTION THROUGH HYPOTHALAMIC VASOPRESSIN-MEDIATED CENTRAL SYMPATHOEXCITATION IN HYPERTENSIVE HEART FAILURE MODEL

Abstract

Objective: Afferent renal nerves may contribute to the development and progression of heart failure, which, however, has not been well investigated. This study aimed to examine whether the afferent renal nerve input contributes to hypertensive cardiac dysfunction. Design and method: Male Dahl salt-sensitive rats were fed 0.3% low-salt diet (LS) or 8% high-salt diet (HS) from 6 weeks of age. HS-fed rats were divided into selective afferent renal denervation (HS-ARDN) or sham operation (HS-Sham) at 9 weeks. The effects of ARDN on central sympathetic regulation were investigated at 12 weeks. In another cohort, its effects on the cardiac phenotypes were evaluated at 16 weeks, with adding total renal denervation (HS-TRDN) group. Results: At 12 weeks, systolic blood pressure (SBP) measured by tail-cuff method was significantly increased in HS-Sham compared to LS, while there was no significant difference between HS-Sham and HS-ARDN. Plasma norepinephrine concentration was increased in HS-Sham compared to LS and was attenuated in HS-ARDN. The c-Fos expression, a neuronal activation marker, in presympathetic neurons within hypothalamic paraventricular nucleus (PVN) and rostral ventral lateral medulla (RVLM) was also increased in HS-Sham and attenuated in HS-ARDN, which was in parallel with the c-Fos expression in vasopressin-expressing neurons within PVN. At 16 weeks, SBP was similarly increased in HS-Sham, HS-ARDN, and HS-TRDN compared to LS. Although the parameters of left ventricular (LV) hypertrophy, such as LV wall thickness by echocardiography and LV weight, were significantly increased in HS-Sham, HS-ARDN, and HS-TRDN compared to LS, there was no significant difference between HS-fed three groups. Echocardiographic LV fractional shortening was significantly decreased in HS-Sham compared to LS, and was attenuated to the same extent in HS-ARDN and HS-TRDN. Histological LV fibrosis determined by Masson trichrome staining and mRNA expression of ANP and CTGF in LV were significantly increased in HS-Sham compared to LS; these changes were similarly ameliorated in both HS-ARDN and HS-TRDN. Conclusion: The input from renal afferent nerves contributes to sympathoexcitation and cardiac dysfunction independently of SBP in Dahl salt-sensitive hypertensive heart failure model. Vasopressin production in PVN may be involved in the renal afferents-mediated sympathetic regulation.