Higher circulating ACE2 and DPP3 but reduced ACE and angiotensinogen in hyperreninemic sepsis patients

Sepsis and septic shock are global healthcare problems associated with high mortality rates. Activation of the renin-angiotensin-aldosterone system (RAAS) is an early event in sepsis, and elevated renin may be predictive of worse outcomes. In a subset of sepsis patients enrolled in the Vitamin C, Thiamine and Steroids in Sepsis (VICTAS) trial, elevated levels of active renin (median value > 189 pg/mL or 5.1 pM) at baseline (day 0) were strongly associated with mortality; however, corresponding plasma levels of the vasopressor hormone Angiotensin II were not substantially increased nor was Angiotensin II associated with disease severity. The current study assessed RAAS components that may impact the Angiotensin II response in control subjects, normal renin sepsis (NRS, renin < 5.1 pM) and high renin sepsis (HRS, renin > 5.1 pM) patients. NRS and HRS subjects exhibited a similar reduction in ACE (40%), but increased levels of ACE2 and DPP3. The ACE to DPP3 ratio was higher in controls but this relationship was reversed in both NRS and HRS subjects. Intact angiotensinogen was 50% lower in the HRS than control or NRS subjects, whereas the intact angiotensinogen to renin ratio was <10% of control or NRS subjects. We conclude that altered expression of ACE, ACE2, DPP3 and angiotensinogen may attenuate the expected increase in Angiotensin II, particularly in sepsis subjects with high renin concentrations.