REN and hypertensive disorder: Interplay between the renin-angiotensin system (RAS), autonomic nervous system (ANS) and the immune system (IS) has been implicated in hypertension (HTN), and cardiovascular disease (CVD) (Santisteban et al., 2013; Han et al., 2016; Hurr and Young, 2016; Wenzel et al., 2016).