Sally I. Hassanein

Triangular relationship between single nucleotide polymorphisms in the CYP2R1 gene (rs10741657 and rs12794714), 25-hydroxyvitamin d levels, and coronary artery disease incidence

Abstract Objective: To investigate the relationship between the rs10741657 and rs12794714 polymorphisms in the CYP2R1 gene, 25(OH)D levels, and coronary artery disease (CAD) incidence. Methods: In total, 134 male patients with verified CAD were recruited, alongside 109 age- and sex-matched controls. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism, using the corresponding restriction enzyme for each polymorphism, whereas 25(OH)D levels were analyzed by HPLC-UV. Results: 25(OH)D levels were significantly lower in patients. The genotypic and allelic distributions of the rs10741657 polymorphism were significantly different between patients and controls, whereas insignificant results were obtained for the rs12794714 polymorphism. Furthermore, rs10741657, but not rs12794714, predicted 25(OH)D levels. Conclusion: The rs10741657 polymorphism is a novel genetic marker for CAD.

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.

Effect of Polymorphisms in the NADSYN1/DHCR7 Locus (rs12785878 and rs1790349) on Plasma 25-Hydroxyvitamin D Levels and Coronary Artery Disease Incidence

Background/Aims: Recent genome-wide association studies have identified the rs1790349 and rs12785878 single-nucleotide polymorphisms (SNPs), present in the NADSYN1/DHCR7 locus, as an influential player on circulating 25-hydroxyvitamin D [25(OH)D] levels, which itself has been linked to various diseases including cardiovascular disease (CVD). This study investigated the association of these SNPs with CVD and 25(OH)D levels. Methods: Sixty- three male patients with verified coronary artery disease (CAD) were recruited, as well as 31 age- and sex-matched controls. Genotyping was performed by sequencing, whereas plasma 25(OH)D levels were assessed by HPLC-UV. Results: Statistical insignificance was observed in comparing the genotype distribution of patients and controls for both the rs12785878 (NADSYN1) polymorphism (p = 0.097) and the rs1790349 (DHCR7; p = 0.9). Comparison of allelic distributions of rs1790349 and rs12785878 yielded insignificant results (p = 0.7, OR: 0.58-2.6 and p = 0.14, OR: 0.88-2.85, respectively). Taking together patients and controls, both SNPs were found to influence total 25(OH)D levels (p = 0.001 and p < 0.0001) as well as 25(OH)D3 levels only in controls. Conclusion: This study further supports the evidence of the ability of the investigated SNPs to predict circulating 25(OH)D levels, nonetheless opposing their use as genetic markers for CAD.

Genetic variation in vitamin D receptor gene (Fok1:rs2228570) is associated with risk of coronary artery disease

Abstract Objective: The Fok1 polymorphism (rs2228570) in vitamin D receptor gene appears to be the only polymorphism influencing size of translated protein. Investigations into its association with coronary artery disease (CAD) are sparse. Methods: Male patients (n = 98) with verified CAD were recruited alongside age- and sex-matched controls (n = 55). Genotyping was performed by PCR-RFLP and plasma 25-Hydroxyvitamin D levels were assessed by HPLC-UV. Results: The C-variant (mutant) was predominantly expressed in patients compared to controls (68.9% versus 55.5%; p = 0.025). The observed genotypes were not associated with 25-Hydroxyvitamin D levels. Conclusion: This study presents Fok1 polymorphism as a potential genetic marker for CAD.

Association of DDAH2 gene polymorphism with cardiovascular disease in Egyptian patients

1992). Elevated levels ofADMA capable of inhibiting endothelial nitric oxide syn-thase (eNOS) have been found in several disorders includ-ing coronary artery disease (CAD) (Boger 2004). Nowa-days, ADMA is regarded as a novel cardiovascular riskfactor and is degraded mainly by an intracellular enzymetermed dimethylarginine dimethylaminohydrolase (DDAH),after uptake from the circulation. DDAH degrades ADMA tocitrulline and dimethylamine (Dayoub

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.

Vitamin D receptor gene polymorphisms (TaqI and ApaI) in relation to 25-hydroxyvitamin D levels and coronary artery disease incidence

Abstract Context/objective: Previous studies have illustrated the association of the ApaI and TaqI polymorphisms of the vitamin D receptor gene, located in non-coding and coding regions, respectively, with diseases such as cancer and cardiovascular disease; however, investigating such association in Egyptian patients with coronary artery disease (CAD) has never been formerly attempted. Materials and methods: Male patients (n = 137), 35–50 years of age, with verified CAD, were recruited alongside age- and sex-matched controls (n = 58). Genotyping and 25-hydroxyvitamin D [25(OH)D] measurement were performed by polymerase chain reaction RFLP and HPLC, respectively. Results: Comparison of the genotypic distribution of both the TaqI and ApaI polymorphisms between patients and controls yielded insignificant results (p = 0.55 and 0.7, respectively). Comparison of the allelic distribution of both polymorphisms also yielded insignificant results. The TaqI polymorphism was not found to predict 25(OH)D levels, whereas the wild-type genotype of the ApaI polymorphism was associated with greater levels of 25(OH)D (p = 0.02), taking all subjects into consideration. Discussion/conclusion: This study presents the ApaI and TaqI polymorphisms as non-influencing players in the pathogenesis of CAD in Egyptian males and the ability of only the ApaI polymorphism to predict 25(OH)D levels, thus warranting further investigations of the triangular relationship between the polymorphisms, 25(OH)D and CAD incidence.

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.

Independent assortment of GC gene polymorphism (rs2282679) and 25-hydroxyvitamin D levels in coronary artery disease

Coronary artery disease (CAD) remains a major public health burden. Emerging research has suggested an association between vitamin D insufficiency and CAD. Vitamin D binding protein (VDBP) is the primary vitamin D carrier and many of its genetic polymorphisms are able to induce the expression of proteins with different affinities for the vitamin, which in turn might affect its serum levels and CAD incidence. One hundred and twelve male patients, aged between 35 and 50 years, with verified CAD and 109 age- and sex-matched controls were recruited. Genotyping was performed by the TaqMan allelic discrimination assay and plasma 25(OH)D levels were assessed by HPLC-UV. Serum parathyroid hormone (s-PTH) and VDBP levels were measured using ELISA. s-25(OH)D levels in CAD patients were significantly lower than in the controls, whereas s-PTH levels were significantly higher in the CAD patients than in the controls. There was no significant difference in the distribution of GC genotypes among both groups. s-25(OH)D showed a weak inverse correlation with s-PTH levels. Serum levels of vitamin D and PTH are highly correlated with CAD incidence. However, the s-VDBP level is associated neither with disease outcome nor with vitamin D status. The GC gene variant has no effect on 25(OH)D levels.