Local Angiotensin-Converting Enzyme 2 Gene Expression in Kidney Allografts Is Not Affected by Renin-Angiotensin-Aldosterone Inhibitors

BACKGROUND: Preclinical studies suggested that pharmacological inhibition of the renin-angiotensin-aldosterone system (RAAS) by ACE inhibitors (ACEis) or angiotensin II receptor blockers (ARBs) may increase local angiotensin-converting enzyme 2 (ACE2) expression. METHODS: In this study, we evaluated the effect of ACEi or ARB treatment on expression of ACE2, ACE, and AGTR1 in 3-month protocol kidney allograft biopsies of stable patients using RT-qPCR (n = 48). Protein ACE2 expression was assessed using immunohistochemistry from paraffin sections. RESULTS: The therapy with RAAS blockers was not associated with increased ACE2, ACE, or ATGR1 expression in kidney allografts and also ACE2 protein immunohistochemistry did not reveal differences among groups. CONCLUSIONS: ACEis or ARBs in kidney transplant recipients do not affect local ACE2 expression. This observation supports long-term RAAS treatment in kidney transplant recipients, despite acute complications such as COVID-19 where ACE2 serves as the entry protein for infection.