Background: Although renal denervation significantly reduces blood pressure in patients with resistant hypertension, the role of the renal nerve in hypertension with metabolic syndrome is unknown. We investigated the impact of long-term renal denervation on SHR/NDmcr-cp(+/+) (SHRcp) rats, a useful rat model of metabolic syndrome, to determine the role of the renal nerve in hypertension with metabolic syndrome.
Methods and results: SHRcp rats were divided into (1) a renal denervation (RD) group and (2) a sham operation group (control) to examine the effects of long-term RD on blood pressure circadian rhythm, renal sodium retention-related molecules, the renin-angiotensin-aldosterone system, metabolic disorders, and organ injury. RD in SHRcp rats not only significantly reduced blood pressure but also normalized blood pressure circadian rhythm from the nondipper to the dipper type, and this improvement was associated with an increase in urinary sodium excretion and the suppression of renal Na(+)-Cl(-) cotransporter upregulation. RD significantly reduced plasma renin activity. RD significantly prevented cardiovascular remodeling and impairment of vascular endothelial function and attenuated cardiovascular oxidative stress. However, RD failed to ameliorate obesity, metabolic disorders, and renal injury and failed to reduce systemic sympathetic activity in SHRcp rats.
Conclusions: By including the upregulation of the Na(+)-Cl(-) cotransporter, the renal sympathetic nerve is involved in the disruption of blood pressure circadian rhythm as well as hypertension in metabolic syndrome. Thus, RD seems to be a useful therapeutic strategy for hypertension with metabolic syndrome.
Keywords: circadian rhythm; hypertension; obesity; renin; sodium.