The Effect of Acute Kidney Injury on TGF-β1 and Smad3 in Patients with Coronary Heart Disease after Off-Pump Coronary Artery Bypass Grafting

BACKGROUND: Acute kidney injury (AKI) is one of the most common and serious complications for coronary disease (CAD) patients, suffering from coronary artery bypass surgery (CABG). AKI occurs in nearly 30% of cardiac surgery patients, including CABG patients, affecting renal function, prolonging hospitalization time, and increasing all-cause mortality. TGF-β1 and Smad3 are sensitive biomarkers in evaluating kidney function. Therefore, comparing the TGF-β1 and Smad3 levels between the AKI patients and non-AKI patients after CABG surgery might have an important significance for identifying the risk degree of AKI and applying effective preventive measures after CABG surgery. OBJECTIVE: This study aims at comparing the TGF-β1 and Smad3 levels between the AKI patients and non-AKI patients after CABG surgery to identify the risk degree of AKI and apply effective preventive measures after CABG surgery in clinics. MATERIALS AND METHODS: A total of 25 proper patients, diagnosed as coronary disease (CAD) and undergoing AKI after CABG, were selected as the AKI group. The 25 participants, who did not suffer from AKI after CABG, were recruited using the case-control matching method in SPSS 25.0 software as the non-AKI group. Also, corresponding surgical specimens (tissues) and samples of blood were collected from them. Histopathological analysis and immunofluorescent microscopy of lesion artery and kidney of patients, who have been treated with kidney transplants, were performed on surgical specimens to find the pathological and histological change difference between the two groups. RT-PCR and Western blot were conducted to quantify the levels of TGF-β1 and Smad3 expression in serum for the patients of AKI and non-AKI groups, respectively. RESULTS: Serious renal fibrosis was noted in patients of the AKI group. In addition, by H&E staining of the lesion artery, severe histopathological changes including smooth muscles proliferation with endothelial cell infiltration, focal degeneration and disruptions, and less collagen accumulation were found in the lesion artery of patients from the AKI group. Higher levels of TGF-β1 and Smad3 were observed in serum of patients of the AKI group. CONCLUSION: : The increased levels of TGF-β1 and Smad3 in serum might be risk factors for triggering AKI for CAD patients undergoing CABG.