Mohamed F. Abdel Rahman

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.

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.

The Role of Nitric Oxide from Neurological Disease to Cancer

Until the beginning of the 1980s, nitric oxide (NO) was just a toxic molecule of a lengthy list of environmental pollutants such as cigarette smoke and smog. In fact, NO had a very bad reputation of being destroyer of ozone, suspected carcinogen and precursor of acid rain. However, by the early 1990s it was well recognized by the medical research community. Over the last two decades, the picture has been totally changed. Diverse lines of evidence have converged to show that this sometime poison is a fundamental player in the everyday business of the human body. NO activity was probed in the brain, arteries, immune system, liver, pancreas, uterus, peripheral nerves, lungs, and almost every system in the human body. NO is a major player in the cardiovascular system as it is involved in regulating blood pressure. In the CNS, it is involved in memory formation and the regulation of cerebral blood flow to ensure adequate supply of blood to the brain. Because NO is involved in many pathways, it has a role in several diseases related to modern life as hypertension, coronary heart diseases, Alzheimers Disease, stroke and cancer. This chapter focuses on the discussion of the role of NO in neurological diseases and cancer and how can this Janus-faced molecule play a role in the pathology and personalized treatment of these diseases.

AGXT2 and DDAH-1 Genetic Variants are Highly Correlated with Serum ADMA and SDMA Levels and with Incidence of Coronary Artery Disease in Egyptians

Dimethylarginine aminodehydrolase (DDAH1) and alanine glyoxylate aminotransferase2 (AGXT2) are two enzymes that contribute in asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) metabolism. Hence they affect production and bioavailability of eNOS-derived nitric oxide (NO) and consequently healthy blood vessels. The major aims of the current study were to investigate the association of genetic variants of AGXT2 rs37369, AGXT2 rs16899974 and DDAH1 rs997251 SNPs with incidence of coronary artery disease (CAD) in Egyptians and to correlate these variants with the serum levels of ADMA and SDMA. The study included 150 subjects; 100 CAD patients and 50 healthy controls. Genotyping was performed by qPCR while the ADMA and SDMA concentrations were assayed by ELISA. Both serum ADMA and SDMA concentrations were significantly higher in CAD patients compared to controls (both p < 0.0001). Genotype distributions for all studied SNPs were significantly different between CAD patients and controls. Carriers of AGXT2 rs37369-T allele (CT + TT genotypes) and AGXT2 rs16899974-A allele (CA + AA genotypes) had 2.4- and 2.08-fold higher risk of having CAD than CC genotype in both SNPs (p = 0.0050 and 0.0192, respectively). DDAH1 rs997251 TC + CC genotypes were associated with 2.3-fold higher risk of CAD than TT genotype (p = 0.0063). Moreover, the AGXT2 rs37369 TT and AGXT2 rs16899974 AA genotypes were associated with the highest serum ADMA and SDMA while DDAH1 rs997251 CC genotype was associated with the highest ADMA. AGXT2 rs37369-T, AGXT2 rs16899974-A, and DDAH1 rs997251-C alleles represent independent risk factors for CAD in the Egyptians.

Genetic Variants of CYP2R1 Are Key Regulators of Serum Vitamin D Levels and Incidence of Myocardial Infarction in Middle-Aged Egyptians

BACKGROUND Myocardial Infarction (MI) is one of the leading causes of morbidity and mortality in Egypt and worldwide. Vitamin D deficiency has long been linked to incidence of cardiovascular diseases. Several factors were reported to contribute to serum vitamin D level including exposure to sunlight. However, genetic variations in the vitamin D metabolic pathways have also been considered as strong determinants of vitamin D levels. CYP2R1 is the major 25-hydroxylase enzyme that is responsible for the 1st activation step of vitamin D. OBJECTIVE to investigate the contribution of polymorphisms in CYP2R1 gene to vitamin D deficiency and incidence of MI in Egyptians. METHODS The study included 323 subjects; 185 MI patients and 138 healthy controls. Serum 25OHD3, 25OHD2 and total 25OHD levels were measured using LC-MS/MS. SNPs rs2060793 and rs1993116 were determined by polymerase chain reaction - restriction fragment length polymorphism (PCRRFLP) which is considered one of the most commonly used techniques in genotyping. SNP rs10766197 was detected using TaqMan allele discrimination assay. RESULTS Serum 25OHD3, 25OHD2 and total 25OHD levels were found to be significantly lower in MI patients than controls. The three studied SNPs were associated with significantly different total 25OHD levels and their genotype distributions differed significantly between MI patients and controls where the high risk genotypes were AG/AA for rs2060793, AG/GG for rs1993116 and AG/AA for rs10766197. Additionally, the concurrent presence of high risk genotypes of the three studied SNPs rendered those individuals at extremely higher risk for MI than each individual SNP (OR 14.1, 95% CI (3.1-64.7), p-value = < 0.0001). CONCLUSIONS Genetic variants of CYP2R1 are key determinants of serum 25OHD levels and are highly associated with MI risk.

C(-260)T Polymorphism in CD14 Receptor Gene of Egyptians with Acute Myocardial Infarction

BACKGROUND Despite the significance of the traditional risk factors, recently published studies have suggested that inflammatory processes and variations in the genetics of the inflammatory system may participate in the initiation of atherosclerosis and its complications. OBJECTIVE To investigate the possible association between CD14 C(-260)T (rs2569190) gene polymorphism and the risk of acute myocardial infarction in the Egyptian population. METHODS We enrolled 100 acute myocardial infarction patients in addition to 107 healthy controls. Deoxyribonucleic acid was extracted, purified and used for the genotype assay of C(-260)T polymorphism in promoter region of CD14 gene. Genotyping was conducted using polymerase chain reactionrestriction fragment length polymorphism. Polymerase chain reaction product was digested using a restriction enzyme and the digestion products were specified. Serum CD14 levels were determined by Enzyme Linked Immunosorbent Assay. RESULTS CD14 genotypic distribution (CC: 15.9% vs. 16%, CT: 62.6% vs. 58%, TT: 21.5% vs. 26% in controls versus acute myocardial infarction patients, p > 0.05 for all variables) and allele frequencies (C allele: 47% vs., 45%, T allele: 52% vs. 55% in controls versus acute myocardial infarction patients, p > 0.05 for all variables) did not show a statistical significant difference. Serum CD14 levels were elevated in acute myocardial infarction patients (5.73±0.62 vs. 4.48±0.28 pg/ml, p < 0.05). However, there was no statistically significant difference in serum CD14 levels among different CD14 genotypes. CONCLUSION CD14 C-(260)T polymorphism is not associated with incidence of acute myocardial infarction in Egyptians who showed elevated serum CD14 levels in comparison to healthy individuals.

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.

Polymorphisms in Gap Junction Proteins and their Role in Predisposition of Acute Myocardial Infarction in Egyptians

BACKGROUND Connexin (Cx) proteins are the building blocks of gap junctions. Among these, Cx37 and Cx40 are expressed on vascular system and reported to have cardioprotective role. Linking polymorphisms in genes coding for Cx and coronary artery disease (CAD) risk showed conflicting results in different populations. None has been studied before in Egyptians. Therefore, the aims of this study were to investigate the influence of Cx37 C1019T and Cx40 A71G polymorphisms on the predisposition of acute myocardial infarction (AMI) in Egyptians, to study linkage disequilibrium (LD) and combined effects of single nucleotide polymorphisms (SNPs) and to correlate the genotypes with sVCAM-1 serum levels. METHODS Total of 201 Egyptian subjects were recruited for the study. They were divided into 104 AMI patients and 97 healthy controls. Genotypes for each participant were determined using a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Serum sVCAM-1was measured by ELISA. RESULTS Allele frequencies for both Cx37 and Cx40 were not significantly different between AMI and Controls (p=0.93 and p=0.26 respectively). Moreover, studying the dominant and recessive models concluded that none of the genotypes was a risk factor. Both SNPs were not in LD (R2=0.0027). Serum analysis showed higher levels of sVCAM-1 in AMI patients (p<0.0001). sVCAM-1 levels were not significantly different among SNPs (Cx37; p=0.244 and Cx40; p=0.266). CONCLUSION This study shows that Cx37 C1019T and Cx40 A71G polymorphisms are not associated with cardioprotective role in Egyptians. Moreover, both SNPs are inherited separately and none of the genotypes were associated with higher sVCAM-1 levels.

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.