Free radical reaction products and antioxidant capacity in beating heart coronary artery surgery compared to conventional bypass

Changes in the Nrf2/Keap1 Ratio and PON1 Concentration in Plasma of Patients Undergoing the Left Main Coronary Artery Stenting

Nuclear factor erythroid 2-related factor2 (Nrf2), together with its inhibitor Kelch-like ECH-associated protein 1 (Keap1), is a crucial regulator of cellular redox response. Nrf2 binds to the antioxidant response element (ARE) present in the DNA sequence of a broad group of antioxidant compounds, including paraoxonase (PON1), inducing their transcription. This study was to answer the question of the effect of temporary ischemia/oxidative stress resulting from the left main stenting via percutaneous coronary intervention (LMPCI) performed in the patients included in this study on the cellular redox balance, which is guarded by the Nrf2/Keap1 interaction. We expected a reflection of the redox imbalance due to reactive oxygen species (ROS) in the change in PON1 concentration observed in the following stages of the study, as well as in total antioxidant capacity (TAC) levels. Our results showed the mobilization of cellular Nrf2/Keap1 team right after the procedure (pre-LMPCI median: 2.532, range: 0.07-11.88; post-LMPCI median: 3.735, range: 0.1545-16.18; 24 h-LMPCI median: 5.596, range: 0.02-49.18), which suggest being the result of oxidative stress that accompanies percutaneous coronary intervention (PCI). The course of Keap1 and Nrf2 concentrations at all stages of the experiment appeared to show that Keap1 shadowed the Nrf2 to switch off its activity after Nrf2 induced the mobilization of the antioxidant response. We observed an increase in PON1 concentration (pre-LMPCI median: 179.3, range: 49.76-6120; post-LMPCI median: 215.7, range: 3.80-2771) and a decrease in the TAC level immediately after PCI (pre-LMPC: $1.008\pm 0.27\text{I}$ , post-LMPCI: $0.8030\pm 0.27$ ). This study design allowed for the first time to analyze the chronology of mechanisms and the relationship between selected parameters reflecting the redox state in patients’ plasma. We may conclude that ischemia induced by the PCI was the source of imbalance in the Nrf2/Keap1 ratio via oxidative stress, and this leads to an increase in PON1 concentration first and, in the next step, the TAC mobilization.

The Effect of On-Pump and Off-Pump Bypass Operations on Oxidative Damage and Antioxidant Parameters

Objective

The aim of the study is to determine the oxidative status in on-pump and off-pump coronary artery surgery and contribute to possible surgical choices in clinical practices in accordance with the information obtained as a result of this study.

Methods

52 patients undergoing open heart surgery (26 patients in on-pump group and 26 patients in off-pump group) were included in the study. MDA, GPx, GSH, CAT, and SOD were investigated in blood samples.

Results

In the on-pump group, it was determined that there were a significant increase in MDA level in the peroperative period compared to the preoperative and postoperative periods and a significant increase in GSH level in the postoperative period than in the preoperative period. Additionally, while there was a significant decrease in CAT activity in the postoperative period than in the peroperative period, there was a statistically significant increase in SOD enzyme activity in the postoperative period compared to the preoperative and peroperative periods. A statistically significant increase was observed in SOD enzyme activity in the postoperative period in on-pump compared to off-pump group.

Conclusion

It is thought that this oxidative damage can be suppressed by administering a suitable antioxidant supplement in the preoperative and peroperative periods among patients undergoing the on-pump operation.

Circulating microRNAs indicate cardioprotection by sevoflurane inhalation in patients undergoing off-pump coronary artery bypass surgery

In patients undergoing off-pump coronary artery bypass surgery (OPCAB), it is important to attenuate myocardium injury during the surgery. The present study aimed to observe the cardioprotection induced by sevoflurane induction and maintenance compared with propofol intravenous anesthesia, and to detect its potential protection against acute myocardial injury with sensitive biomarkers. In total, 36 patients undergoing OPCAB were randomly assigned into two groups, receiving sevoflurane (n=18) or propofol (n=18) as the induction and maintenance anesthetic agent. The depth of anesthesia in the two groups was kept at a bispectral index value of 40-50. Physiological and hemodynamic parameters were recorded during the surgery. Cardiac troponin-I (cTnI), creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) and two microRNAs (miR-499 and miR-208b) were also measured during and subsequent to surgery. Nno statistically significant differences were observed in the physiological and hemodynamic parameters between the two groups prior to surgery. Following surgery, the cardiac output and stroke volume improved significantly in the sevoflurane group (P<0.05). In addition, patients in the sevoflurane group had lower miR-499 (P<0.05) and miR-208b (P<0.01) levels at 12 h after surgery when compared with the propofol group. However, no significant differences in cTnI, CK-MB and LDH levels were observed following surgery between the two groups. In conclusion, volatile induction and maintenance with sevoflurane resulted in some extent of cardiac function improvement in patients undergoing OPCAB. Cardioprotection by sevoflurane is suggested by reduced cardiac injury compared with propofol, and indicated by the sensitive biomarkers, circulating miR-499 and miR-208b.

Circulating miR-126 and miR-499 reflect progression of cardiovascular disease; correlations with uric acid and ejection fraction

BACKGROUND

The aim of this study was to assess plasma levels of endothelium- and heart-associated microRNAs (miRNAs) miR-126 and miR-499, respectively, using quantitative reverse transcriptase polymerase chain reaction.

METHODS

A two-step analysis was conducted on 75 patients undergoing off-pomp coronary artery bypass graft (CABG) surgery. Five biomarkers of inflammation and cardiac injury were assessed in addition to the above-mentioned miRNAs.

RESULTS

Plasma concentrations of miRNAs were found to be significantly correlated with plasma levels of cardiac troponin I (cTnI) (miR-499, r 0.49, p~0.002; miR-126, r = 0.30, p~0.001), indicating cardiac damage. Data analysis revealed that miR-499 had higher sensitivity and specificity for cardiac injury than miR-126, which reflects more endothelial activation. Interestingly, a strong correlation was observed between both miRNAs and uric acid (UA) levels with ventricular contractility measured as ejection fraction (EF) (miR-499/EF%, r = 0.58, p~0.004; UA/EF%, r = -0.6, p~0.006; UA/miR-499, r = -0.34; UA/miR-126, r = 0.5, p~0.01).

CONCLUSIONS

In patients undergoing CABG, circulating miR-126/499 is associated with presentation of traditional risk factors and reflects post-operative response to injury. Plasma pool of miRNAs likely reflects extracellular miRNAs which are proportional to intracellular miRNA levels. Therefore, circulating levels of these miRNAs have prognostic implications in detection of higher risk of future cardiovascular events.

Does high thoracic epidural analgesia with levobupivacaine preserve myocardium? A prospective randomized study

Background. Our study aimed to compare HTEA and intravenous patient-controlled analgesia (PCA) in patients undergoing coronary bypass graft surgery (CABG), based on haemodynamic parameters and myocardial functions. Materials and Methods. The study included 34 patients that were scheduled for elective CABG, who were randomly divided into 2 groups. Anesthesia was induced and maintained with total intravenous anesthesia in both groups while intravenous PCA with morphine was administered in Group 1 and infusion of levobupivacaine was administered from the beginning of the anesthesia in Group 2 by thoracic epidural catheter. Blood samples were obtained presurgically, at 6 and 24 hours after surgery for troponin I, creatinine kinase-MB (CK-MB), total antioxidant capacity, and malondialdehyde. Postoperative pain was evaluated every 4 hours until 24 hours via VAS. Results. There were significant differences in troponin I or CK-MB values between the groups at postsurgery 6 h and 24 h. Heart rate and mean arterial pressure in Group 1 were significantly higher than in Group 2 at all measurements. Cardiac index in Group 2 was significantly higher than in Group 1 at all measurements. Conclusion. Patients that underwent CABG and received HTEA had better myocardial function and perioperative haemodynamic parameters than those who did not receive HTEA.

Changes of sFas and sFasL, oxidative stress markers in serum and follicular fluid of patients undergoing IVF

PURPOSE

The Fas-Fas Ligand interaction is one of the essential events for the induction of apoptosis whereas the exact role of their soluble forms in the reproductive system is still not fully understood. Also oxidative stress in the pathogenesis of infertility causing diseases in women and has been suggested as one of the important factors that negatively affect IVF outcome. In this study, our aim was to evaluate serum and follicular fluid levels of soluble Fas soluble Fas Ligand, malondialdehyde, superoxide dismutase and total antioxidant capacity in patients undergoing IVF and compared with controls.

METHODS

This study included 109 patients. Patients were classified as unexplained infertility (N = 31), PCOS (N = 19), tubal factor (N = 9) and endometriosis (N = 10) and compared with male factor infertility (N = 40) that was the control group. sFas and sFasL levels were measured by immunoassay method. MDA, SOD and TAC levels were measured by colorimetric method.

RESULTS

Patients with unexplained infertility, PCOS and tubal factor had significantly lower sFas levels compared with their controls (respectively, p < 0.01, p < 0.05, p < 0.05). However, SOD activity in unexplained infertility, PCOS and endometriosisgroupswere significantly higher than control group (p < 0.01).Decreased follicular fluid TAC levels were found in all patient groups compared with controls (respectively, p < 0.01, p < 0.05, p < 0.01, p < 0.01).Patients with tubal factor had significantly higher serum sFasL (p < 0.05), but lower follicular fluid sFasL levels (p < 0.05) compared with unexplained infertility. Tubal factor and endometriosis groups had lowerfollicular fluid TAC levels compared to unexplained infertility and PCOSgroups (p < 0.01).

CONCLUSION(S)

In this study, serum and follicular fluid sFas levels were decreased and antioxidant activity was impaired in infertility, possibly implying increased apoptosis. Especially in unexplained infertility group changes in this parametres more remarkable.

A preliminary study about the effects of warm priming solution on oxidative stress and postoperative atrial fibrillation in open heart surgery

BACKGROUND

An important reason for production of ischemia and reperfusion injury and oxidative stress is the sudden and rapid changes in body temperature during the institution of cardiopulmonary bypass. The aim of this study was to investigate the effects of warm priming solution on oxidative stress and atrial fibrillation.

METHODS

This is a preliminary prospective study on a group of 40 patients who underwent elective coronary artery bypass grafting operation using cardiopulmonary bypass. Patients were randomized into two groups, each consisting of 20 patients; one group was primed with a solution at 20 °C and the other at 36 °C initially for cardiopulmonary bypass. Blood samples from both of the groups were drawn preoperatively and at the 15th and 60th min of aortic cross clamping and 24th h following the surgery. Serum malondialdehyde levels, protein carbonyl content and total antioxidant status were detected. Patients were followed for postoperative atrial fibrillation.

RESULTS

Malondialdehyde and protein carbonyl content were found to be significantly higher and total antioxidant status was concordantly lower in the cold priming group at the 15th and 60th min, recovering to the normal range postoperatively at the 24th h. Patients in the cold priming group had developed a significantly higher rate of atrial fibrillation when compared with the patients in the warm priming group during the postoperative period.

CONCLUSION

In conclusion, although this study has its limitation about the sample size it may provide an insight about the probable preventive effects of 36 °C warm priming solution in oxidative stress and postoperative atrial fibrillation.

Nitric oxide and the CABG patient

The post surgery success of coronary artery bypass grafting (CABG) is counteracted by thrombosis and de-endothelialization, intimal hyperplasia and, over the long term, atherosclerosis. There are many reasons to assume that in CABG patients vascular bioavailability of NO generated by the endothelium plays an important role for graft function. This holds true for factors such as graft type, harvesting and storage, the type of surgery, non-pharmacologic prevention of risk factors, for example, regular physical activity (if feasible), and drug therapy. Although the precise role of graft endothelial NO bioavailability for graft patency and clinical endpoints is still uncertain, current data rather speak in favor of NO indicating that the potential of vasoprotective activities of NO in the CABG patient deserves further investigation.

Effect of citrate phosphate dextrose solution on reperfusion injury in coronary artery bypass surgical patients undergoing cardiopulmonary bypass

INTRODUCTION

Reperfusion injury is one of the most common phenomena associated with coronary artery bypass graft (CABG) .The mechanism of ischemia and reperfusion injury is not known precisely, but may be free radicals and other activated oxygen metabolites have an important role in tissue damage following reperfusion injury. This study was to evaluation of citrate solution effects on oxidative stress and cardiac function and Cardiac enzymes in patient's candidate to CABG.

METHODS

In Double blind clinical trial study in Tabriz University of medical science, 50 patients candidate to CABG randomly divided in two groups and matched together according to sex, age and NYHA class. In intervention group after surgery and before the opening of the aortic clamping solution warm blood containing citrate phosphate dextrose (CPD; 3cc/100cc), value (100cc/min/m2BSA) for three minutes was administered. In control group, only pure blood administered. Oxidative stress markers measured in five stages and cardiac enzymes measured in three stages of surgery.

RESULTS

Mean age 62.3±9.1 years including 30(60%) men and 20(40%) women. Ejection fractions between two groups were not significant before and after treatment. Administration of CPD was not significant effects on cardiac enzyme. Measurement of oxidative stress in different time were not different in malonil dialdehyde, superoxide dismutase and GPx but total antioxidant status were improved after intervention in compared with control group (p<0.001).

CONCLUSION

Results showed that CPD were positive effects of increasing in total antioxidant status after CABG, but in reduction of other oxidative markers were unlabeled.