Efeito de soluções de preservação na modulação da síntese de sulfeto de hidrogênio no endotélio da veia safena magna na cirurgia de revascularização do miocárdio

Abstract

The great saphenous vein (GSV) remains widely utilized in coronary artery bypass grafting (CABG), yet venous grafts exhibit limited long-term patency despite recent advances. Endothelial preservation is critical for improving graft outcomes. During CABG, vascular conduits are stored in preservation solutions, which influence endothelial integrity and the expression of functional molecules. Hydrogen sulfide (H2S), a multifaceted gasotransmitter with vasodilatory, anti-inflammatory, and antithrombotic effects, has an underexplored role in GSV grafts. This study aimed to evaluate the effect of different preservation solutions on the expression of H2S-producing enzymes and GSV endothelial integrity. GSV segments from twenty CABG patients were divided into five groups: Control (immediate fixation post-excision), normal saline (NS), autologous heparinized blood (AHB), histidine-tryptophan-ketoglutarate solution (HTK), and no solution (Damage). Post-fixation, segments were analyzed by light microscopy (LM) to assess graft integrity and endothelial coverage percentage, and by immunofluorescence (IF) to quantify CD31, endothelial nitric oxide synthase (eNOS), and H2S-synthesizing enzymes: cystathionine γ-lyase (CSE), cystathionine β-synthase (CBS), and 3-mercaptopyruvate sulfurtransferase (3-MPST). LM analysis showed that AHB and HTK better preserved endothelial structure and coverage compared to NS and Damage groups (p < 0.001). IF analysis revealed that surgical handling attenuated enzyme expression, with preservation solutions showing a protective effect, which was significantly less pronounced with NS. All three H2S-synthesizing enzymes were detected in GSV endothelium, with CSE being the most expressed. Preservation solutions influenced enzyme expression, with AHB and HTK exhibiting a protective effect, maintaining higher CSE, CBS, and 3-MPST levels compared to NS. This study confirms the presence of H2S-producing enzymes in GSV endothelium and demonstrates that preservation solutions used during CABG affect their expression and endothelial integrity and functionality, with NS being deleterious to the endothelium.