Acute cyclooxygenase inhibition and baroreflex sensitivity in lean and obese adults.

PURPOSE: Obese adults exhibit increased levels of inflammation, which may negatively affect blood pressure regulation. Based on existing literature, we hypothesized: (1) baroreflex sensitivity would be lower in obese adults when compared to lean adults; (2) acute ibuprofen (IBU, a cyclooxygenase inhibitor and nonsteroidal antiinflammatory agent) administration would increase baroreflex sensitivity in obese adults, with no effect in lean adults.

METHODS: Seven lean (4 male, 3 female) and six obese (5 M, 1 F) adults completed two visits randomized to control (CON) or IBU (800 mg oral). On each visit, blood pressure (intra-arterial catheter), heart rate (ECG), and muscle sympathetic nerve activity (MSNA, microneurography) were measured continuously. Sympathetic and cardiac baroreflex sensitivities were assessed using the modified Oxford technique.

RESULTS: Measures of systemic inflammation [C-reactive protein (CRP) and interleukin-6 (IL-6)] were higher in obese adults when compared to lean adults and tended to decrease with IBU (IL-6: p < 0.05; CRP: p = 0.14). Cardiac baroreflex sensitivity was lower in obese adults (14 ± 2 vs. 24 ± 2 ms/mmHg, p = 0.02), whereas sympathetic baroreflex sensitivity was higher in obese adults (-3.6 ± 0.5 vs. -2.1 ± 0.5 bursts/100 beats/mmHg, p = 0.03) when compared to lean. There was no effect of IBU on cardiac or sympathetic baroreflex sensitivity in either group (p value range 0.20-0.71).

CONCLUSION: Despite obese individuals exhibiting higher levels of systemic inflammation and lower cardiac baroreflex sensitivity when compared to lean adults, an acute dose of IBU has no effect on cardiac or sympathetic baroreflex sensitivity.