REN and hypertensive disorder: Recent studies have identified several possible interconnected mechanisms between gut dysbiosis and hypertension [9,10], such as altered microbial composition, increased production of microbiota-derived trimethylamine-N-oxide (TMAO), changes of short chain fatty acids (SCFAs) and their receptors, impaired nitric oxide (NO) pathway, and dysregulation of the renin-angiotensin system (RAS).