Association of In Vivo β-Adrenergic Receptor Sensitivity With Inflammatory Markers in Healthy Subjects

Objective: Several stress-related states and conditions that are considered to involve sympathetic overactivation are accompanied by increased circulating levels of inflammatory immune markers. Prolonged sympathetic overactivity involves increased stimulation of the beta-adrenergic receptor (beta-AR). Although prior research suggests that one mechanism by which sympathetic stimulation may facilitate inflammation is via beta-AR activation, little work has focused on the relationship between circulating inflammatory immune markers and beta-AR function within the human body (in vivo). We examined whether decreased beta-AR sensitivity, an indicator of prolonged beta-adrenergic overactivation and a physiological component of chronic stress, is related to elevated levels of inflammatory immune markers. Methods: Ninety-three healthy participants aged 19 to 51 years underwent the chronotropic 25 dose isoproterenol test to determine in vivo beta-AR function. Circulating levels. of C-reactive protein, interleukin 6, and soluble tumor necrosis factor receptor 1 were determined. Results: beta-AR sensitivity was lower in people with higher C-reactive protein concentrations (r = 0.326, p = .003). That relationship remained significant after controlling for sociodemographic and health variables such as age, sex, ethnicity, body mass index, mean arterial blood pressure, heart rate, leisure-time exercise, and smoking status. No significant relationship was found between chronotropic 25 dose and interleukin 6 or soluble tumor necrosis factor receptor 1. Conclusions: This study demonstrates a link between in vivo beta-adrenergic receptor function and selected circulating inflammatory markers (CRP) in humans. Future studies in specific disease states may be promising.