Nehir Sucu

Glutathione S-transferase gene polymorphism as a susceptibility factor in smoking-related coronary artery disease

Abstract.Coronary artery disease (CAD) is the leading cause of morbidity and mortality in the world, and cigarette smoking is a major contributing factor to the disease. Glutathione S-transferase (GST) enzyme is implicated in the detoxification of carcinogens present in tobacco smoke and consequent polymorphisms in this gene may confer susceptibility to cardiovascular disease if DNA damage is important in CAD. Therefore, we examined this question in a case-control study of subjects having coronary atheroma by angiography and with a past history of myocardial infarction (MI). The study population consists of 247 healthy controls and 148 consecutive patients who had undergone coronary angiography for suspicion of coronary artery disease. DNA was extracted from whole blood, and the GSTM1 and GSTT1 polymorphisms were determined using a real-time polymerase chain reaction (PCR). We found that the null GSTM1 and GSTT1 genotypes were associated with an increase in the risk of developing coronary heart disease (OR = 1.14; 95% CI: 0.71 – 1.82; OR = 1.38; 95% CI: 0.82 – 2.32), respectively, but this increase was not significant. Patients who smoke having the null genotypes of GSTM1 (OR: 1.63 (1.10 – 2.63)) and GSTT1 (2.66 (1.50 – 4.72)) and both (3.20 (1.37 – 7.45)) were at a higher risk for developing coronary heart disease. In conclusion, the finding of a significant association between GSTM1 and T1 with smoking status may influence cardiovascular disease via DNA damage.

The effects of caffeic acid phenethyl ester on tissue damage in lung after hindlimb ischemia-reperfusion

AIM The aim of this study was to investigate the effects of caffeic acid phenethyl ester (CAPE) on the lungs as a remote organ after performing hindlimb ischemia-reperfusion (I/R) and by assessing biochemical and histopathological analysis. METHODS The animals were divided into three groups: control, I/R, and I/R with CAPE. I/R period for 8 h was performed on the right hindlimb of all the anesthesied rats in I/R and CAPE with I/R group. In the CAPE with I/R group, the animals received CAPE 10 microM by intraperitoneal injection 1h before the reperfusion. The animals in the control and I/R groups received a similar volume of saline solution by means of intraperitoneal injection. At the end of the reperfusion period, a midsternotomy was performed. Blood, bronchoalveolar lavage (BAL) and lung tissue were obtained, and were used for biochemical and histopathological examination. RESULTS The tissue and serum malondyaldehyde levels were significantly lower in the control (P=0.0001 and 0.001, respectively) and in the CAPE with I/R groups (P=0.0001 and 0.003, respectively) compared to the I/R group. Tissue Na(+)-K(+) ATPase activity in the CAPE with I/R group was significantly higher than in the I/R group (P=0.0001). Reduced activity was found in the I/R group compared to the control group (P=0.0001). Myeloperoxidase activity (P=0.001) and protein concentration (P=0.034) in BAL were significantly reduced in CAPE-treated animals when compared with the I/R group. A decreased activity and protein concentration were found in the control group compared to the I/R group (P=0.0001 and 0.024, respectively). The lungs of the I/R group displayed intense peribronchial and perivascular leukocytic infiltration in histopathological examination compared to the CAPE with I/R group (P<0.05). CONCLUSION CAPE seems to be effective in protecting remote organ injury caused by increased oxidative stress and neutrophil accumulation that results from an I/R injury.

N-Acetylcysteine for Preventing Pump-Induced Oxidoinflammatory Response During Cardiopulmonary Bypass

PurposeTo investigate the effect of N-acetylcysteine on preventing pump-induced oxidoinflammatory response during cardiopulmonary bypass (CPB).MethodsForty patients undergoing coronary artery bypass grafting (CABG) were randomly divided into a study group (n = 20), given 50 mg kg−1N-acetylcysteine intravenously for 3 days, and a control group (n = 20) given saline. Serum samples were collected for measurement of myeloperoxidase (MPO), malondialdehyde (MDA), interleukin-6, Α1-acid glycoprotein (AAGP), and C-reactive protein (CRP) during surgery and postoperatively.ResultsThe MPO and MDA values showed a similar pattern during and after CPB in the study group, with significantly less variance than in the control group. Interleukin-6 showed similar patterns in the two groups, but the data from 30 min after the start of CPB and from 6 h post-CPB were significantly different. The AAGP and CRP values were both elevated during CPB in the two groups without a significant difference, but 6 and 24 h post-CPB, the values were significantly higher in the control group than in the study group.ConclusionsN-Acetylcysteine decreased pump-induced oxidoinflammatory response during CPB, suggesting that it could be a novel therapy for assisting in the prevention of CBP-induced oxidoinflammatory damage.

Decreased Serum Total Antioxidant Status and Erythrocyte-Reduced Glutathione Levels Are Associated with Increased Serum Malondialdehyde in Atherosclerotic Patients

BACKGROUND Coronary artery disease is the significant cause of morbidity and mortality today. The treatment of coronary artery disease is improving, but its prevalence is increasing. Both primary and secondary prevention measures are of vital importance. METHODS In this study, vitamin C, total antioxidant status, malondialdehyde in serum and erythrocyte-reduced glutathione levels were investigated in patients with atherosclerosis and compared with those of controls. Levels of serum MDA, vitamin C, total antioxidant status, and erythrocyte-reduced glutathione were determined according to the methods of Yagi, Bauer et al., Miller et al., and Beutler, respectively. RESULTS Erythrocyte-reduced glutathione, serum vitamin C, total antioxidant status, and malondialdehyde values of both patients with atherosclerosis and controls were as follows: 2.80 +/- 0.76, 5.82 +/- 0.67 micromol GSH/g Hb; 1.00 +/- 0.19, 1.62 +/- 0.30 mg/dL; 0.86 +/- 0.14, 1.43 +/- 0.16 mmol/L, and 4.26 +/- 0.9, 1.02 +/- 0.80 nmol/mL, respectively. There was a decrease in the levels of serum vitamin C, erythrocyte-reduced glutathione, and total antioxidant status (p <0.001), and increase in the levels of serum malondialdehyde (p <0.001) in patients with atherosclerosis when compared with those of controls. CONCLUSIONS Because treatment of atherosclerosis is improving, our results suggest that antioxidant agents may have preventive roles in the formation of atherosclerosis.

3-Nitrotyrosine in atherosclerotic blood vessels

Abstract The effect of peroxynitrite on the development of atherosclerosis is one of the major foci of recent studies. Here, the cytotoxic effect of peroxynitrite was investigated by quantitatively measuring nitrated tyrosine, 3-nitrotyrosine (3-NT) levels in atherosclerotic blood vessels. Atherosclerotic vessels were obtained from the patients who underwent either coronary artery or peripheric artery bypass surgery. Internal thoracic arteries of the patients were treated as non-atherosclerotic control vessels. 3-NT was measured by reverse-phase HPLC and plasma nitrite-nitrate levels were measured by spectrophotometry. 3-NT levels were significantly elevated in atherosclerotic vessels (46.6±23.3 nmol/mg protein, n = 15; p < 0.001) in comparison to control vessels (15.8±2.5 nmol/mg protein, n = 10). Vessel 3-NT correlated weakly with plasma nitrate levels (r = 0.38). Thus, atherosclerotic arteries have higher 3-NT levels than non-atherosclerotic blood vessels.

Alcohol-induced lung damage and increased oxidative stress.

Background: Alcohol-induced lung damage may be associated with increased oxidative stress. Objective: Our aim was to investigate alcohol-induced changes in the biochemistry and histopathology of the lung. Methods: Rats were divided into two groups, a control group and an ethanol group. The ethanol group received 2 g/kg ethanol (total: 3 ml) intraperitoneally. The controls were given the same amount of saline via the same route. Three hours later, the rats were sacrificed, and blood and lung tissue samples were obtained. Oxidative stress was assessed by measuring the levels of erythrocyte reduced glutathione (GSH), tissue malondialdehyde (MDA), myeloperoxidase (MPO) and Na+-K+ ATPase. Histopathologic evaluation of the lung tissues was also performed. Results: In the ethanol group, serum and tissue MDA levels and MPO activities were increased (p = 0.007, p = 0.001 and p = 0.000), and lung tissue Na+-K+ ATPase activities and erythrocyte GSH were decreased (p = 0.001 and p = 0.000) compared to the controls. Histopathologic examination demonstrated alveolocapillary thickening, alveolar degeneration, leukocyte infiltration and erythrocyte extravasation in the lungs of the ethanol group (p < 0.05). Conclusion: These results suggest that high-doseacute alcohol administration aggravates systemic and local oxidative stress leading to acute lung injury, ranging from mild pulmonary dysfunction to severe lung injury. It should be borne in mind that rapid onset of the acute respiratory distress syndrome (ARDS) may also be due to increased oxidative stress following alcohol abuse, especially when ischemic disturbances, e.g. coronary heart disease, acute ischemia of the extremities and traumatic accidents, are concomitantly present. Therefore, precautions against ARDS may prevent morbidity and mortality in alcohol-induced lung damage in at-risk patients.

Effects of trimetazidine on tissue damage in kidney after hindlimb ischemia-reperfusion.

The objective of this study was to investigate the effects of trimetazidine (TMZ) on tissue damage in kidney after hindlimb ischemia-reperfusion (I/R), by assessing blood biochemical assay and histopathological analysis. Adult male Wistar rats were divided into two groups. TMZ 10 mg kg(-1)day(-1) was administrated twice a day for 10 days to the treatment group (group T, n=10). Sham group was given only 5% gum arabic (group S, n=10). On 11th day of treatment, 8h I/R period was performed on right hindlimb of the rats. At the end of reperfusion period, a 5 ml blood withdrawn from ascending aorta for biochemical assays and their right kidneys were harvested for histopathological examination. Superoxide dismutase, Na(+)-K(+) ATPase, and reduced glutathione levels were significantly increased in group T (P<0.001). On the other hand, myeloperoxidase and malondialdehyde levels were significantly less in group T than group S (P<0.001). Kidneys from the sham-operated group displayed intense leukocytic infiltration in histopathological examination. These overall results strongly suggested that TMZ contributes renal protection from hindlimb I/R injury by decreasing systemic oxidative stress.

Effects of Daflon on oxidative stress induced by hindlimb ischemia/reperfusion.

The objective of this study was to investigate the effects of Daflon 500 mg on tissue damage in kidney after ischemia/reperfusion hindlimb, by assessing blood biochemical assay and histopathological analysis. Rats were given Daflon 80 mg x kg(-1) x day(-1) for 10 days. On 11th day of treatment, 4h ischemia followed by 4 h reperfusion period was performed on right hind limb of the rats. Control groups were given only arabic gum and were subjected to same ischemia/reperfusion period. At the end of reperfusion period, erythrocyte superoxide dismutase, Na(+)-K(+) ATPase and reduced glutathione levels were increased in the rats erythrocytes in Daflon group (P<0.01, for all). On the other hand, serum myeloperoxidase and malondialdehyde levels were significantly lower in the Daflon-received rats (P<0.01, for all). Histopathological studies demonstrated that, there was a prominent tubulointerstitial injury with loss of brush border and this degeneration was accompanied by segmental glomerular degeneration also for both control and Daflon group. Daflon-received group animals displayed significantly less periglomerular and perivascular leukocytic infiltration (P=0.015). These overall results suggest that Daflon contributes renal protection from hind limb ischemia/reperfusion injury in some degree, by decreasing systemic oxidative stress.

Contribution of RhoA/Rho-kinase/MEK1/ERK1/2/iNOS pathway to ischemia/reperfusion-induced oxidative/nitrosative stress and inflammation leading to distant and target organ injury in rats.

The small G protein RhoA and its downstream effector Rho-kinase play an important role in various physiopathological processes including ischemia/reperfusion (I/R) injury. Reactive oxygen and nitrogen species produced by iNOS and NADPH oxidase are important mediators of inflammation and organ injury following an initial localized I/R event. The aim of this study was to determine whether RhoA/Rho-kinase signaling pathway increases the expression and activity of MEK1, ERK1/2, iNOS, gp91(phox), and p47(phox), and peroxynitrite formation which result in oxidative/nitrosative stress and inflammation leading to hindlimb I/R-induced injury in kidney as a distant organ and gastrocnemius muscle as a target organ. I/R-induced distant and target organ injury was performed by using the rat hindlimb tourniquet model. I/R caused an increase in the expression and/or activity of RhoA, MEK1, ERK1/2, iNOS, gp91(phox), p47(phox), and 3-nitrotyrosine and nitrotyrosine levels in the tissues. Although Rho-kinase activity was increased by I/R in the kidney, its activity was decreased in the muscle. Serum and tissue MDA levels and MPO activity were increased following I/R. I/R also caused an increase in SOD and catalase activities associated with decreased GSH levels in the tissues. Y-27632, a selective Rho-kinase inhibitor, (100µg/kg, i.p.; 1h before reperfusion) prevented the I/R-induced changes except Rho-kinase activity in the muscle. These results suggest that activation of RhoA/Rho-kinase/MEK1/ERK1/2/iNOS pathway associated with oxidative/nitrosative stress and inflammation contributes to hindlimb I/R-induced distant organ injury in rats. It also seems that hindlimb I/R induces target organ injury via upregulation of RhoA/MEK1/ERK1/2/iNOS pathway associated with decreased Rho-kinase activity.

Pressure applied during surgery alters the biomechanical properties of human saphenous vein graft

Pressure applied during harvesting of the saphenous vein (SV) graft in coronary artery bypass surgery might change its mechanical properties and thereby decrease the patency. This study was performed to assess the mechanical properties of the SV graft distended manually with different levels of pressure and to determine the pressure level that induces changes in its structure and mechanics. Saphenous vein graft segments, collected from 36 patients undergoing coronary artery bypass surgery, were distended with pressures of either 50–60, 75–100, or 130–150 mmHg. Grafts were tested for the stress–strain relationship; the Young’s moduli at the low- and high-strain regions were calculated, and their structures were examined by light and electron microscopy. Pressures of 50–60 mmHg did not influence the mechanics of the vein graft, whereas pressures of 75–100 mmHg elevated the elastic modulus of the vein at the low-strain region while pressures above 130 mmHg increased the elastic moduli at both low- and high-strain regions. There was a prominent loss of microfibrils at all distending pressure levels. The mechanical results suggest that distending pressures above 75 mmHg might play a role in graft failure. Furthermore, the absence of microfibrils surrounding elastin suggests that application of distending pressures, even as low as 50 mmHg, can cause degeneration of the elastic fibers following implantation, increasing the stiffness of the graft and thus impairing the graft’s function under its new hemodynamic conditions.