REN and acute kidney injury: In sepsis, the expression of vasoactive hormone receptors is reduced, which further weakens the vascular bed, induces peripheral vasodilation, excites the sympathetic nervous system, and activates renin-angiotensin system, thereby causing blood vessels to constrict continuously, spasm to glomerular afferent arteries, decrease kidney blood flow, and induce hypoxic-ischemic conditions, finally leading to acute kidney injury (Sharma et al., 2019).