Circulating angiotensin-converting enzyme 2 activity in kidney transplantation: a longitudinal pilot study

Area of Science:

• Cardiovascular research
• Renal transplant research
• Enzymology

Background:

• Angiotensin-converting enzyme 2 (ACE2) is a key enzyme in the renin-angiotensin system, degrading angiotensin II.
• The specific role of ACE2 in kidney transplant (KT) recipients remains largely unexplored.
• Understanding ACE2's function in KT is crucial for managing post-transplant complications.

Purpose of the Study:

• To investigate circulating ACE2 activity in kidney transplant (KT) patients.
• To determine the relationship between serum ACE2 activity and patient demographics, graft function, and cardiovascular risk markers.
• To explore the potential of serum ACE2 as a non-invasive biomarker in KT.

Main Methods:

• A cross-sectional study involving 113 KT patients with stable graft function.
• Assessment of circulating ACE2 activity using a fluorescent assay.
• Correlation and multiple regression analyses to identify predictors of ACE2 activity.

Main Results:

• Circulating ACE2 activity was detectable and elevated in KT patients with ischemic heart disease and in males compared to females.
• ACE2 activity showed positive correlations with serum creatinine, urea, age, liver enzymes (AST, ALT, γ-GT), and glycosylated hemoglobin.
• Age, serum creatinine, and serum γ-glutamyl transferase (γ-GT) were identified as independent predictors of serum ACE2 activity.

Conclusions:

• Circulating ACE2 activity can be reliably measured in kidney transplant recipients.
• Serum ACE2 activity is directly associated with patient age, renal allograft function, and liver function parameters.
• Serum ACE2 measurement may serve as a valuable non-invasive biomarker for assessing the renin-angiotensin system's involvement in kidney transplant outcomes.