Molecular hydrogen: prospective treatment strategy of kidney damage after cardiac surgery

Abstract

Cardiac surgery-associated acute kidney injury (CS-AKI) is a common postoperative complication, mostly due to increasing oxidative stress. Recently, molecular hydrogen (H2 gas), has also been applied to cardiac surgery due to its ability to reduce oxidative stress. We evaluated the potential effect of H2 application on the kidney in an in vivo model of simulated heart transplantation. Pigs underwent cardiac surgery within 3 hours while connected to extracorporeal circulation (ECC) and subsequent 60 minutes of spontaneous reperfusion of the heart. We used two experimental groups: T - pigs after transplantation, TH - pigs after transplantation treated with 4% H2 mixed with air during inhalation of anesthesia and throughout oxygenation of blood in ECC. The levels of creatinine, urea and phosphorus were measured in plasma. Renal tissue samples were analyzed by Western blot method for protein levels of Nrf2, Keap-1, and SOD1. After cardiac surgery, selected plasma biomarkers were elevated. However, H2 therapy was followed by the normalization of all these parameters. Our results suggest activation of Nrf2/Keap1 pathway as well as increased SOD1 protein expression in the group treated with H2. The administration of H2 had a protective effect on the kidneys of pigs after cardiac surgery, especially in terms of normalization of plasma biomarkers to control levels.

Study details

Article type

Original Research

Disease / injury model

Cardiac surgery-associated acute kidney injury (CS-AKI) in pigs (simulated heart transplantation)

Duration

4 hours

Dose-dependent effect

No

Outcome

Positive

Findings

Administration of 4% molecular hydrogen during simulated heart transplantation in pigs normalized plasma biomarkers of kidney injury (creatinine, uric acid, phosphorus, calcium) and activated the Nrf2/Keap1 pathway and SOD1 expression, indicating a protective effect against acute kidney injury after cardiac surgery.