Effects of multielectrode renal denervation on elevated sympathetic nerve activity and insulin resistance in metabolic syndrome

Objective: This study aimed to investigate the effects of renal denervation (RDN) on sympathetic nerve activity and insulin resistance in patients with metabolic syndrome. Methods: Seventeen patients fulfilled at least four of five criteria for metabolic syndrome and under stable use of at least two antihypertensive drugs were randomized in 3 : 1 ratio to RDN (n=13, 12 men, age: 58±7 years) and control groups (n=4, three men, age: 60±5 years) and followed up for 3 months. Muscle sympathetic nerve activity (MSNA) at rest and during standard 75 g oral glucose tolerance test (OGTT) was assessed. Results: In the RDN group, office and average 24-h blood pressures reduced by 16±21/10±11mmHg (P=0.01/ 0.007) and 14±16/5±8 mmHg (P=0.008/0.03) respectively; waist circumference reduced by 3.1±3.6cm (P=0.008); and resting MSNA reduced from 55±9 bursts per minute to 46±8 bursts per minute (P=0.0008) at month 3 post-RDN. During OGTT, although blunted MSNA responses were noted at baseline throughout the 120-min test, improved MSNA responses with burst frequency increased to 52±8 bursts per minute (P<0.001 vs. the resting MSNA, n=13) at 30 min and to 54±8 bursts per minute (P=0.004 vs. the resting MSNA, n=10) at 120 min and were observed at month 3 post-RDN. No such improvements were observed in the controls. No significant change was observed in the HOMA-IR in both groups at month 3. Conclusion: In this pilot study of patients with metabolic syndrome and associated hypertension, RDN reduced elevated sympathetic nerve activity and restored the normal neural response to oral glucose loading.