No impact of sex and age on beta-adrenoceptor mediated inotropy in human right atrial trabeculae.

AIM There is an increasing awareness of the impact of age and sex on cardiovascular diseases. Differences in physiology are suspected. Beta-adrenoceptors (beta-AR) are an important drug target in cardiovascular disease and potential differences might have significant impact on the treatment of many patients. To investigate whether age and sex affects beta-AR function, we analyzed a large data set on beta-AR-induced inotropy in human atrial trabeculae. METHODS We performed multivariable analysis of individual atrial contractility data from trabeculae obtained during heart surgery of patients in sinus rhythm (535 trabeculae from 165 patients). Norepinephrine or epinephrine were used in the presence of the beta2 -selective antagonist (ICI 118,551, 50nM) or the beta1 -selective antagonist (CGP 20712A, 300 nM) to stimulate beta1 -AR or beta2 -AR, respectively. Agonist concentration required to achieve half maximum inotropic effects (EC50 ) was taken as a measure of beta-AR sensitivity. RESULTS Impact of clinical variables was modeled using multivariable mixed model regression. As previously reported, chronic treatment with beta-blockers sensitized beta-AR. However, there was no significant interaction between basal force, maximum force or beta-AR sensitivity when age and sex were modelled continuously. In addition, there was no statistically significant effect of body mass index or diabetes on atrial contractility. CONCLUSION Our large, multivariable analysis shows that neither age nor sex affects beta-AR-mediated inotropy or catecholamine sensitivity in human atrial trabeculae. These findings may have important clinical implications because beta-adrenoceptors, as a common drug target in cardiovascular disease and heart failure do not behave differently in women and men across age decades.