Contribution of glutathione peroxidase 1 (Pro200Leu) single nucleotide polymorphism and serum homocysteine levels in the risk of acute myocardial infarction in Egyptians.

BACKGROUND: Oxidative stress is among the most common risk factors in the pathogenesis of acute myocardial infarction (AMI). Glutathione peroxidase 1 enzyme coded by the GPX1 gene plays an essential role in reducing oxidative stress. Previous studies correlated the GPX1 (Pro200Leu) single nucleotide polymorphism (SNP) with AMI incidence. Elevated homocysteine (Hcy) levels induce oxidative stress and are considered an independent risk factor for AMI. Evidence showed a complex relationship between Hcy and GPx-1 activity. This study examined the association of the common (Pro200Leu) SNP in GPX1 with AMI incidence in an Egyptian population. This study is the first to check this association in an Egyptian population. Moreover, the association between serum Hcy and the incidence of AMI was checked, and the novelty was to statistically correlate GPX1 Pro200Leu genotypes with serum Hcy levels in patients and control subjects. Hundred control subjects and hundred and twenty AMI patients were genotyped using PCR-RFLP analysis. An ELISA was used to measure serum Hcy levels. RESULTS: The GPX1 (Pro200Leu) genotype distribution and allele frequency were not significantly different between patients and control subjects (P = 0.60 and P = 0.62, respectively). Serum levels of Hcy were significantly elevated in patients compared to control subjects (P ≤ 0.0001). However, no significant difference was observed in serum Hcy levels among different GPX1 genotypes in neither patients nor control subjects. CONCLUSIONS: The minor T allele of GPX1 Pro200Leu is not associated with AMI risk in this Egyptian population. However, high homocysteine serum levels might contribute independently to the risk of AMI. Finally, Hcy levels were not significantly different in homozygous minor TT compared to homozygous wild CC.

The Association of Fractalkine Receptor (T280M) Polymorphism in the Pathogenesis of Acute Coronary Syndrome in the Egyptian Population.

BACKGROUND: Fractalkine (FKN) in its free and membrane bound-forms and its receptor CX3CR1are reported to have an atherosclerotic effect. The relationship of Single Nucleotide Polymorphisms (SNPs) in FKN and CX3CR1genes with the Coronary Artery Disease (CAD) risk showed conflicting results in different populations. The aim of this study was to investigate the influence of CX3CR1 threonine 280 methionine (T280M) polymorphism in the predisposition of Acute Coronary Syndrome (ACS) in Egyptians. METHODS: 200 Egyptian subjects were recruited for the study. They were divided into 100 ACS patients and 100 healthy controls. Genotyping of CX3CR1 T280M was performed using a Polymerase Chain Reaction-restriction Fragment Length Polymorphism (PCR-RFLP). Serum FKN was assayed by Enzyme - Linked - Immuno- Sorbent-Assay (ELISA). RESULTS: T and M allele frequencies for CX3CR1gene were not significantly different between ACS and Controls (p=0.76). Moreover, none of the genotypes had an atheroprotective effect. Serum analysis showed higher levels of FKN in ACS patients (p=0.041). FKN levels were not significantly different among genotypes of control and ACS groups (p=0.34) and (p=0.38) respectively. CONCLUSION: This study shows that CX3CR1 T280M polymorphism does not affect the incidence of ACS the Egyptian population. Moreover, none of the genotypes were associated with higher FKN levels.

Association of Cholesterol Ester Transfer Protein Taq IB Polymorphism With Acute Coronary Syndrome in Egyptian National Patients.

BACKGROUND: The association between cholesterol ester transfer protein (CETP) Taq IB polymorphism and coronary artery disease (CAD) has been studied in different populations. Acute coronary syndrome (ACS) is a group of clinical symptoms within acute myocardial ischemia, including unstable angina (UA) and myocardial infarction (MI). Because there are no data reported in the literature concerning the cholesteryl ester transfer protein (CETP) Taq IB polymorphism in Egyptians, our study aimed to investigate the frequency of different CETP Taq IB genotypes in Egyptian patients with ACS and in healthy control individuals. METHODS: The current study was conducted with 70 hospitalized patients who had been diagnosed with ACS and 30 controls. We used real-time polymerase chain reaction (RT-PCR) to determine CETP Taq IB in individuals with different genotypes. RESULTS: The frequency of the GA genotype was significantly lower in UA patients, compared with the control group ( P <.05). CONCLUSIONS: The frequency of the CETP Taq IB genotypes and alleles in all groups was similar to that in other ethnic groups. Individuals with the Taq IB GA genotype may have a lower risk of UA.

Association of manganese superoxide dismutase Ala16Val polymorphism in the incidence of acute myocardial infarction in the Egyptians.

Background: Oxidative stress has been implicated in various diseases including atherosclerosis; the most common pathologic process underlying acute myocardial infarction (AMI). The manganese superoxide dismutase (MnSOD) antioxidant enzyme affords the major defense against reactive oxygen species (ROS) within the mitochondria. MnSOD Alanine16Valine (A16V) single nucleotide polymorphism (SNP) has been shown to decrease MnSOD detoxification activity. Aim: A case-control study was conducted to investigate the association between MnSOD A16V polymorphism and the incidence of AMI in the Egyptians, investigate the contribution of oxidative stress represented by hexanoyl lysine adduct (HEL), an oxidative stress biomarker, in the pathogenesis of AMI and finally correlate the MnSOD genotypes with HEL serum levels. Methods: A total of 200 Egyptian subjects were recruited for the study; 100 AMI patients and 100 control subjects. Genotypes of the MnSOD A16V polymorphism were determined using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Serum HEL was measured by ELISA. Results: A significant difference in the distribution of the MnSOD A16V genotypes was observed; VV genotype was significantly higher in AMI than controls (p ≤ 0.0001). Also, studying the allele frequencies revealed that Val allele was significantly higher in AMI than controls (p ≤ 0.0001). Serum analysis showed higher levels of HEL in AMI patients (p = 0.0142). Furthermore, HEL levels were found to be significantly higher in VV genotype in AMI (p = 0.0273). Conclusions: Our study suggests that MnSOD A16V polymorphism is associated with increased risk of developing AMI in the Egyptians. Moreover, the VV genotype is associated with higher HEL levels.

Investigation of brain-derived neurotrophic factor (BDNF) gene expression in hypothalamus of obese rats: Modulation by omega-3 fatty acids.

PURPOSE: The aim of this study was investigating the effect of omega-3 fatty acids (ω-3 FAs) on brain-derived neurotrophic factor (BDNF) gene expression, using in vivo and in vitro models, to unravel the potential mechanisms of polyunsaturated fatty acids use in obesity. MATERIALS AND METHODS: Twenty-nine Sprague-Dawley rats were divided into three groups; lean controls fed normal chow diet for 14 weeks, obese controls fed 60% of their diet as saturated fats for 14 weeks, and ω-3 FAs-treated rats fed 60% saturated fat diet for 14 weeks with concomitant oral administration of 400 mg/kg/day ω-3 FAs, mainly docosahexaenoic acid and EPA, from week 12 to week 14. For the in vitro experiment, hypothalamic cells from six obese rats were cultured in the presence of different concentrations of ω-3 FAs to determine its direct effect on BDNF expression. RESULTS: In vivo results showed that obesity has negative effect on BDNF gene expression in rat hypothalamus that was reversed by administration of ω-3 FAs. Obese rats showed hypercholesterolemia, hypertriglyceridemia, normoinsulinemia, hyperglycemia and hyperleptinemia. Treatment with ω-3 FAs showed significant decrease in serum total cholesterol and TAG. Also serum glucose level and HOMA index were decreased significantly. In vitro results demonstrated the increase in BDNF expression by ω-3 FAs in a dose-dependent manner. CONCLUSIONS: Obesity causes down-regulation of BDNF gene expression that can be reversed by ω-3 FAs treatment, making them an interesting treatment approach for obesity and metabolic disease.

Assessment of the link between endothelin K198n Snp, endothelin concentration and acute myocardial infarction in Egyptians.

The aim of the current study was to assess the link between EDN K198N SNP, ET-1 serum concentration and acute myocardial infarction (AMI) in Egyptians. The study cohort consisted of 84 patients at AMI onset and 84 age-matched healthy controls. Endothelin genotypes and concentrations were determined by sequencing and ELISA, respectively. Genotype distribution was not significantly different between AMI patients and controls (P=.8341). The mean serum ET-1 concentration of patients (13.83±0.7 pg/mL) was significantly higher than controls (7.26±0.2 pg/mL) (P<.0001). ET-1 serum concentrations did not vary significantly among various EDN genotypes in patients (P=.378) and controls (P=.6164). Hence, we conclude that EDN K198N genotypes were not related to either ET-1 concentration or incidence of early-onset AMI in Egyptians. But, AMI patients had higher ET-1 concentrations than controls.

Addressing the link between paraoxonase-1 gene variants and the incidence of early onset myocardial infarction.

INTRODUCTION: The enzyme paraoxonase-1 (PON1) represents an endogenous defense mechanism against vascular oxidative stress, thereby contributing to the prevention of atherosclerosis. Several polymorphisms have been reported in the PON1 gene, including Q192R. PON1 phenotype is commonly expressed as the paraoxonase/arylesterase ratio (PON/ARE). The major aim of this study was to investigate the association between PON1 Q192R polymorphism, PON1 phenotypes and the incidence of early-onset acute myocardial infarction (AMI) in Egyptians. MATERIAL AND METHODS: The study subjects consisted of 102 AMI patients and 72 age-matched healthy controls. Genotyping and enzyme activities were determined using PCR-RFLP and kinetic spectrophotometric assays, respectively. RESULTS: The genotype distribution for the PON1 gene was significantly different between AMI patients (QQ = 38.24%, QR = 49.02%, RR = 12.75%) and controls (QQ = 66.67%, QR = 25%, RR = 8.33%). Allele frequencies were also significantly different between patients (Q = 62.75%, R = 37.25%) and controls (Q = 79.17%, R = 20.83%). The genotypes QR and RR showed higher risk for AMI compared to the homozygous QQ (odds ratio (OR) = 3.231, p < 0.001). The average PON/ARE ratio in MI patients (1.187 ±0.1) did not differ significantly from controls (1.118 ±0.26). However, it showed a significant difference among different genotypes in both AMI patients (QQ = 0.91 ±0.11, QR = 1.09 ±0.11 and RR = 2.65 ±0.4) (p = 0.0002) and controls (QQ = 0.68 ±0.1, QR = 1.07 ±0.11 and RR = 4.89 ±2.84) (p < 0.0001). CONCLUSIONS: PON1 192R allele represents an independent risk factor for early-onset AMI in Egyptians, and PON1 Q192R polymorphism modulates the paraoxonase phenotype.

C242T polymorphism of NADPH oxidase p22phox gene reduces the risk of coronary artery disease in a random sample of Egyptian population.

The p22phox protein subunit is essential for NADPH oxidase activity. The prevalence of C242T variants of p22phox gene was studied in 101 healthy Egyptian controls and 104 acute myocardial infarction (AMI) Egyptian patients. Contribution of oxidative stress, represented by serum oxidized-LDL (ox-LDL), in development of AMI was also examined and correlated with C242T gene variants. Genotyping and ox-LDL were assessed by PCR-RFLP and ELISA. Results showed that wild type CC genotype is prevalent in 27 % of controls; CT and TT are in 72 and 1 %. In patients, the distribution was 40.2, 59.8 and 0 % for CC, CT and TT; respectively, showing a significant difference (p = 0.0259). Serum ox-LDL levels were higher in patients than controls (p ≤ 0.0001). Subjects having CT genotype had lower levels of ox-LDL than CC genotype (p ≤ 0.005). C242T polymorphism of p22phox gene of NADPH oxidase is a novel genetic marker associated with reduced susceptibility to AMI.

Endothelial nitric oxide synthase (G894T) gene polymorphism in a random sample of the Egyptian population: comparison with myocardial infarction patients.

AIM: The aim of this study was to detect endothelial nitric oxide synthase (eNOS) Glu298Asp gene variants in a random sample of the Egyptian population, compare it with those from other populations, and attempt to correlate these variants with serum levels of nitric oxide (NO). The association of eNOS genotypes or serum NO levels with the incidence of acute myocardial infarction (AMI) was also examined. METHODS: One hundred one unrelated healthy subjects and 104 unrelated AMI patients were recruited randomly from the 57357 Hospital and intensive care units of El Demerdash Hospital and National Heart Institute, Cairo, Egypt. eNOS genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism. Serum NO was determined spectrophotometrically. RESULTS: The genotype distribution of eNOS Glu298Asp polymorphism determined for our sample was 58.42% GG (wild type), 33.66% GT, and 7.92% TT genotypes while allele frequencies were 75.25% and 24.75% for G and T alleles, respectively. No significant association between serum NO and specific eNOS genotype could be detected. No significant correlation between eNOS genotype distribution or allele frequencies and the incidence of AMI was observed. CONCLUSION: The present study demonstrated the predominance of the homozygous genotype GG over the heterozygous GT and homozygous TT in random samples of Egyptian population. It also showed the lack of association between eNOS genotypes and mean serum levels of NO, as well as the incidence of AMI.

Protective effect of L-arginine in experimentally induced myocardial ischemia: comparison with aspirin.

OBJECTIVE: Coronary artery diseases including myocardial ischemia (MI) remain one of the leading causes of death worldwide. This study was designed to compare the protective effect of L-arginine versus aspirin from the biochemical changes associated with MI injury. EXPERIMENTAL DESIGN: Four groups of male New Zealand white rabbits were investigated. Normal group (n = 8) rabbits were fed standard chow pellets, untreated MI group (n = 16), where hypercholesterolemia was induced by feeding the animals with a diet containing 2% cholesterol for 28 days, L-arginine group (n = 12) rabbits were fed a 2% cholesterol-enriched diet in conjunction with L-arginine (2.25 g %) in drinking water for 28 days, and aspirin group (n = 12) rabbits were fed 2% cholesterol-enriched diet in conjunction with aspirin administered orally (0.7 mg/kg per d) for 28 days. After 28 days, MI was induced in all groups, except the normal group, by a single subcutaneous (sc) injection of isoproterenol hydrochloride (0.2 mg/kg body weight [bw]). Animals were sacrificed 6 hours later. RESULTS: Our results showed that L-arginine was more effective than aspirin in reducing platelet aggregation, reducing low-density lipoprotein (LDL) oxidizability, preventing aortic intimal thickening, and maintaining histological architecture of the myocardium. Both drugs, however, had similar positive effects on plasma fibrinogen levels and on the prevention of myocardial release of cardiac troponin I and creatine kinase-MB. The effect on hypercholesterolemia was insignificant for both drugs. Aspirin was more effective than L-arginine in prolonging prothrombin time. CONCLUSION: L-arginine supplementation represents a potentially novel nutritional strategy for preventing and treating coronary artery diseases especially in cases of aspirin resistance and/or hypersensitivity.

Assessment of serum levels of asymmetric dimethylarginine, symmetric dimethylarginine and L-arginine in coronary artery disease.

Serum asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), L-arginine, and C-reactive protein (hsCRP) levels were assessed in 100 Egyptian male 35-50-year-old patients with coronary artery disease (CAD), classified into: patients under conservative medical treatment, patients directed for percutaneous coronary interventions, patients directed for coronary artery bypass graft operation and patients suffering from acute myocardial infarction. Age- and sex-matched controls (n=100) were included. Correlation between serum levels of biomarkers and dimethylarginine dimethylaminohydrolase-2 (DDAH-2) genotypes was studied. No association between biomarkers and carriage of the specific DDAH2 SNP2 (-449C/G, rs805305) genotype was detected. Further studies are required to confirm the contribution of the biomarkers in the predisposition of CAD.

Naringenin attenuates cisplatin nephrotoxicity in rats.

The effect of naringenin (NAR), a naturally occurring citrus flavanone, on the acute nephrotoxicity produced by cisplatin (7 mg/kg, i.v.) was investigated in the rat. Oral administration of NAR (20 mg/kg/day) for 10 days, starting 5 days before cisplatin single i.v. injection, produced significant protection of renal function. NAR reduced the extent of cisplatin-induced nephrotoxicity, as evidenced by significant reduction in serum urea and creatinine concentrations, decreased polyuria, reduction in body weight loss, marked reduction in urinary fractional sodium excretion and glutathione S-transferase (GST) activity, and increased creatinine clearance. Cisplatin-induced alterations in renal cortex lipid peroxides and GST activity were markedly improved by NAR. Cisplatin-induced alterations in renal cortex antioxidant defense system were greatly prevented by NAR. In cisplatin-NAR combined treatment group, antioxidant enzymes namely superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were significantly increased to 54.5, 30.3 and 35.6%, respectively compared to cisplatin treated group. Platinum renal content was not affected by NAR treatment. The results provide further insight into the mechanisms of cisplatin-induced nephrotoxicity and confirm the antioxidant potential of NAR.

Cardiac DT-diaphorase contributes to the detoxification system against doxorubicin-induced positive inotropic effects in guinea-pig isolated atria.

1. Doxorubicin (DOX), a standard chemotherapeutic anthracycline agent, causes a positive inotropic effect in guinea-pig isolated atria in a concentration-dependent manner with an ED(50) of 3.6 micromol/L. This increase in contractility is strictly related to the generation of reactive oxygen species (ROS) as a consequence of quinone metabolism. The ED(50) of DOX is significantly increased (P < 0.05) in the presence of 150 U superoxide dismutase (SOD). In the heart, DOX may be subjected to one- or two-electron reductions catalysed by flavoenzymes in the presence of suitable electron donors. Two-electron reduction is catalysed by NAD(P)H quinone acceptor oxidoreductase (DT-diaphorase; DTD). Whether DOX will be activated or detoxified by two-electron reduction is important for the understanding of the mechanism of both the toxic and antitumour actions of DOX. 2. In order to assess the role of DTD in cardiac responses to DOX, we examined the effect of both a specific inhibitor (dicoumarol) and an inducer (3-methylcholanthrene; MCA) of the enzyme on the inotropic action of DOX. 3. In guinea-pig isolated left atria, 4 micromol/L dicoumarol significantly enhanced the positive inotropic effect of DOX, especially at lower concentrations of DOX. In atria isolated from guinea-pigs treated with MCA (44 mg/kg, i.p. for 4 days), DTD activity was enhanced (approximately twice that of the control; P < 0.01), whereas the activity of glutathione S-transferase (GST) was not significantly altered. In these preparations, DOX caused a significantly lower increase in force of contraction than in atria isolated from untreated animals. 4. These results demonstrate that cardiac DTD does not contribute to ROS generation, but represents a detoxification system.