Zbigniew Gaciong

SIMVASTATIN REDUCES SYMPATHETIC ACTIVITY IN MEN WITH HYPERTENSION AND MILD HYPERCHOLESTEROLEMIA: PP.32.257

Objectives: Statins might reduce cardiovascular risk in hypertensive subjects far beyond their hypolipidemic effect. Several mechanisms of that action, including reduction of sympathetic activity have been suggested. Therefore we investigated the hypothesis, that simvastatin decreased muscle sympathetic nerve activity (MSNA) in hypertensive subjects with hypercholesterolemia. Design and method: Thirty one hypertensive hypercholesterolemic patients (aged 38.7 ± 10 yrs) participated in randomized, placebo controlled, double blinded study. Patients (n = 15) were assigned to simvastatin (40 mg/day) or placebo (n = 16) and treated for 8 weeks. In all patients before and after therapy MSNA, systolic and diastolic blood pressure, heart rate and baroreceptors sensitivity were measured, and blood samples for plasma catecholamines, neuropeptide Y, aldosteron, endothelin concentrations and plasma renin activity measurements were taken. Results: Simvastatin significantly reduced MSNA (from 36.5 ± 5 to 27.8 ± 6 burst/minute, p = 0.001), heart rate (from 77 ± 6.7 to 71 ± 6.1 beats/min, p = 0.01) and both total and LDL cholesterol (from 249 ± 30.6 to 184 ± 28.3 mg/dL, p = 0.001 and from 169 ± 30.6 to 117 ± 31.2 mg/dL, p = 0.01, respectively). Baroreceptor sensitivity increased during simvastatin therapy (from 10.3 ± 4.1 to 17.1 ± 4.3 ms/mm Hg, p = 0.04), while no changes were observed in systolic and diastolic blood pressure, plasma catecholamines, neuropeptide Y, endothelin, aldosteron concentration and plasma renin activity. MSNA and baroreceptor sensitivity after simvastatin therapy was inversely related (r = - 0.94, p < 0.05). Conclusion: Simvastatin reduced MSNA in patients with hypertension and hypercholesterolemia. MSNA reduction after therapy with simvastatin was related to increased baroreceptor sensitivity.

DIURNAL RHYTHM OF NEUROPEPTIDE Y AND CATECHOLAMINES IN HYPERTENSIVE DIPPERS AND NON-DIPPERS: PP.32.259

Objective: Causes of circadian blood pressure rhythm disturbances are not well understood. In hypertensive non-dippers increased catecholamines concentration was found. Neuropeptide Y (NPY) is potent neurotransmitter and mediator of the sympatho-adrenomedullary system, potentially involved in pathogenesis of hypertension. Therefore we investigated circadian rhythm of NPY in dippers (D) and nondippers (ND). Design and Methods: The study included 43 untreated hypertensive subjects (24F/19 M) in mean age 50 ± 11 yrs divided into 30 D and 13 ND. Blood samples for NPY, noradrenalin (NA) and adrenalin (A) were taken in 2, 6, 10 AM and 2, 6, 10 PM. Ambulatory blood pressure monitoring (SpaceLabs 20707) were performed in all patients. Results: Mean plasma NPY concentration during the day (dNPY) was compared to NPY at 2 PM (2NPY). In D dNPY was significantly higher than 2NPY (D 7,83 ± 2,99 vs 5,61 ± 3,35 fmol/ml; p < 0,0087). In ND dNPY was similar to 2NPY (8,37 ± 3,18 vs 7,33 ± 4,17 fmol/ml; NS). In D plasma 2NPY was higher, while in ND similar to NPY measured at 6AM, 10AM, 2 PM, 6 PM and 10PM. Plasma NA and A patterns were similar to that of NPY, respectively in D and ND. Plasma NA at 2 AM was higher in ND than in D (430 ± 308 vs 243 ± 160 pg/ml; p < 0,016). Analysis of variance showed circadian rhythm of NPY in D (F=3,77; p < 0,005) and did not in ND (F = 0,53;p = 0,746). Analysis also revealed circadian rhythm of NA and A in D and no in ND. Conclusion: Presented data showed that ND in contrast to D are characterized by abnormal circadian rhythm of NPY and catecholamines. It may suggest a role for NPY in development of non-dipping status in hypertensive patients.