SYMPATHETIC NERVOUS SYSTEM ACTIVITY AND BLOOD PRESSURE IN HYPERTENSIVE PATIENTS WITH NONALCOHOLIC FATTY LIVER DISEASE

Abstract

Objective: Nonalcoholic fatty liver disease (NAFLD) is associated with hypertension and predicts future cardiovascular events. The purpose of this study was to investigate the effect of sympathetic nervous system (SNS) overactivity on blood pressure levels in hypertensive patients with and without NAFLD. Design and method: 111 newly diagnosed untreated hypertensive patients (mean age 55 ± 10 years, 48 males, mean office systolic/diastolic BP 140 ± 14.8/88 ± 9.9 mmHg) without history of cardiovascular disease underwent office blood pressure (BP) measurements. NAFLD was diagnosed by liver ultrasound to separate patients into those with and without NAFLD. SNS activity was assessed by muscle sympathetic nerve activity (MSNA) based on established methodology (microneurography). Results: Hypertensive patients with NAFLD (n = 71) compared to those without NAFLD (n = 40) were younger (53 ± 10 vs 58 ± 9 years, respectively, p = 0.01) with greater body mass index (33 ± 10 vs 26 ± 3 kg/m2, p < 0.001). Also, male gender was more prevalent in the NAFLD group compared to the non-NAFLD group (52% vs 29%, respectively, p = 0.03), whereas there were no differences in glucose, low density lipoprotein levels and glomerular filtration rate. In NAFLD patients, MSNA was correlated with office diastolic BP (r = 0.24, p = 0.02) and in linear multiple regression analysis MSNA levels were an independent determinant of office diastolic BP levels (beta = 0.185, p = 0.05), while in the non NAFLD group, MSNA was not related to office BP levels (p = ns). MSNA levels were greater in hypertensives with NALFD compared to those without NAFLD (44.3 ± 9.5 vs 40 ± 7.5 bursts per minute, respectively, p < 0.04). Moreover, in multiple logistic regression analysis, MSNA was proven as an independent determinant of the presence of NAFLD (OR 1.2, 95% CI 1.01–1.5), p = 0.04). Conclusions: higher sympathetic nervous system activity, as assessed by MSNA, is associated with greater diastolic BP in NAFLD patients compared to their non-NAFLD counterparts. These findings suggest that SNS may contribute importantly to the regulation of BP in NAFLD patients.