# Assessment of Selected Biochemical Parameters of the Renin–Angiotensin–Aldosterone System in Repeat Convalescent Plasma Donors in the Context of Long-Term Changes Following SARS-CoV-2 Infection

## TL;DR

This study examines how SARS-CoV-2 infection affects the renin–angiotensin–aldosterone system (RAAS) in plasma donors over time, finding some biochemical changes persist beyond 120 days.

## Contribution

The study provides new insights into long-term RAAS modulation in repeat convalescent plasma donors following SARS-CoV-2 infection.

## Key findings

- Most RAAS-related biochemical parameters increased post-infection but normalized after 120 days.
- Ang 1–7 and Ang 1–9 remained elevated beyond 120 days compared to controls.
- ADAM10 and ADAM17 correlated with angiotensin peptides, indicating prolonged RAAS modulation.

## Abstract

Background: SARS-CoV-2 infection has been associated with long-term health consequences, including dysregulation of the renin–angiotensin–aldosterone system (RAAS). This study aimed to evaluate long-term changes in selected RAAS-related biochemical parameters in repeat convalescent plasma donors, focusing on enzymes and peptides involved in vascular regulation and inflammation. Methods: Thirty repeat convalescent plasma donors were enrolled, each providing four serum samples at defined time points post-infection. Samples were collected during Period 1 (≤60 days), Period 2 (61–90 days), Period 3 (91–120 days), and Period 4 (>120 days) after confirmed SARS-CoV-2 infection. The analyzed parameters included angiotensin I (Ang I), angiotensin II (Ang II), angiotensin 1–7 (Ang 1–7), angiotensin 1–9 (Ang 1–9), ACE, ACE2, ADAM10, and ADAM17. Concentrations were determined using ELISA assays. The control group consisted of pre-pandemic serum samples from healthy individuals. Results: An initial post-infection increase was observed in most parameters, particularly in Period 1. Over time, levels of several markers declined, yet Ang 1–7 and Ang 1–9 remained elevated compared to controls even beyond 120 days. Significant correlations (p < 0.05) were found between ADAM10, ADAM17, and angiotensin peptides, suggesting prolonged RAAS modulation. Metalloproteinases were notably elevated early after infection, potentially contributing to inflammatory and cardiovascular responses. Conclusions: The findings indicate a transient but measurable biochemical response of the RAAS following SARS-CoV-2 infection, with most parameters normalizing after 120 days. However, the sustained elevation of certain markers suggests a potential long-term impact on vascular homeostasis, warranting further investigation.