Effect of Coronary Artery Disease risk SNPs on serum cytokine levels and cytokine imbalance in Premature Coronary Artery Disease.

BACKGROUND: Premature Coronary Artery Disease (PCAD) occurs almost a decade earlier in the South Asian population as compared to the West. Inclusion of genetic information can prove to be a robust measure to improve early risk prediction of PCAD. Aim was to estimate the genotypic distribution and risk allele frequencies of 13 Coronary Artery Disease (CAD) risk Single Nucleotide Polymorphisms in loci identified by the CARDIoGRAMplusC4D consortium namely MIA3 rs17465637; 9p21 rs10757274; CXCL12 rs1746048; APOA5 rs662799; APOB rs1042031; LPA rs3798220; LPA 10455872; MRAS rs9818870; LPL rs328; SORT1 rs646776; PCSK9 rs11591147; APOE rs429358; APOE rs7412 in Pakistani PCAD patients and controls. Moreover, the differential serum cytokine levels (IL-18, IL-10, IL-6, TNF-alpha, IL-18:IL-10 & TNF-alpha:IL-10 ratios) with respect to the genotypic distribution of these selected SNPs were determined. MATERIAL AND METHODS: The case-control study was carried out in National University of Sciences and Technology, Islamabad in collaboration with the Cardiovascular Genetics Institute, University College London, UK. Subjects (n=340) with >70% stenosis in at least a single major coronary artery on angiography were taken as PCAD cases along with 310 angiographically verified controls. ELISA was performed for measuring the concentrations of serum IL18, TNFA, IL6 and IL10. Genotyping was done using TAQMAN and KASPar assays. RESULTS: The risk allele frequencies (RAF) of APOE rs7412, CXCL12 rs1746048, 9p21 rs10757274, MIA3 rs17465637 and SORT1 rs646776 were significantly higher in the PCAD cases as compared to the controls. APOE rs429358 had the greatest influence among the selected GWAS/CARDIoGRAMplusC4D consortium CAD risk SNPs by significantly altering the serum levels of TNF-alpha, IL-10 and TNF-alpha:IL-10 ratio. It was followed by APOE rs7412 and CXCL12 rs1746048 which significantly altered the serum levels of IL-18; TNF-alpha and IL-18; IL-18:IL-10 ratio respectively. The cytokine imbalance denoted by IL-18:IL-10 was significantly higher in the risk allele carriers MIA3 rs17465637 and CXCL12 rs1746048 while TNF-alpha:IL-10 ratio was significantly raised in the risk allele carriers of APOE rs429358; MRAS rs9818870 and LPL rs328. CONCLUSION: The association of the selected SNPs with differential serum cytokine levels especially the cytokine imbalance points towards their potential causal role in the immune inflammatory pathogenic pathway of PCAD.

Comparison of lipid profiles and lipoprotein a levels in patients with type 2 diabetes mellitus during oral hypoglycemic or insulin therapy.

OBJECTIVE: The aim of this study is to compare lipid and lipoprotein (a) profiles in patients with type 2 diabetes mellitus (DM) on insulin and oral hypoglycemic therapy. METHODS: The study took place in the Department of Physiology, Army Medical College, Rawalpindi, Pakistan, during 2002. Ninety-seven type 2 DM patients participated in the study. We divided the patients according to the type of treatment into sulphonylurea (n=40), sulphonylurea plus metformin (n=33) and insulin (n=24) therapy groups as well as 40 healthy subjects served as controls. Fasting blood samples were analyzed for lipoprotein (a) [Lp (a)], total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), glucose, glycosylated hemoglobin (HbA1c) and insulin. RESULTS: Different groups of diabetic patients showed elevated fasting blood glucose (FPG) levels (p<0.0001 for all), HbA1c (p<0.0001 for all) compared with controls. Meanwhile, fasting insulin levels were elevated only in insulin treated group compared with oral hypoglycemic treated groups and controls (p<0.0001 for all). Patients on sulphonylurea and on sulphonylurea plus metformin groups showed significantly elevated TC (p<0.001, p<0.0001), TG (p<0.001, p<0.01), LDL-C (p<0.01, p<0.001) and LDL-C/HDL-C (p<0.0001, p<0.0001) compared with controls. Insulin therapy group showed significantly decreased TC, TG, LDL-C, LDL-C/HDL-C levels compared with sulphonylurea and sulphonylurea plus metformin treated groups, however, no significant difference was noted in the levels of above mentioned parameters and controls. Meanwhile, HDL-C levels were significantly lower in all diabetic groups compared with controls and were higher in insulin treated group compared with sulphonylurea plus metformin therapy group (p<0.05). Lipoprotein (a) levels were significantly higher in different diabetic groups compared with controls. While there was a non-significant difference in Lp (a) levels between different diabetic groups. CONCLUSION: Patients with type 2 DM who are being treated on insulin have a better lipid profile (TC, HDL-C, LDL-C, TG) compared with those patients on oral hypoglycemic agents. Meanwhile, Lp (a) levels were raised in all diabetic patients and seem not to be affected either by insulin or by oral hypoglycemic treatment.

Role of Cytokine Gene Score in Risk Prediction of Premature Coronary Artery Disease.

AIMS: Pro- and anti-inflammatory cytokines play a significant role in early atherosclerosis. Linkage disequilibrium patterns differ between ethnic groups pointing toward the need to develop population-specific gene risk scores. Our objective was to investigate the role of a cytokine gene score in the risk prediction of premature coronary artery disease (PCAD). METHODS: A case-control study was performed at the National University of Sciences and Technology (NUST) in collaboration with the Cardiovascular Genetics Institute, University College London, United Kingdom. Three hundred forty subjects with >70% stenosis in at least one coronary vessel on angiography were labeled as PCAD cases and compared with 310 angio-negative controls. Genotyping of the rs187238 (interleukin [IL]-18), rs1800795 (IL-6), rs1800629 (tumor necrosis factor [TNF]-alpha), rs1800871 (IL-10), and rs1946519 (IL-18) SNPs was performed using KASPar and TaqMan assays. RESULTS: The odds ratio for cytokine gene score was significantly higher for PCAD (p = 0.025) when adjusted for age, sex, and ethnicity. There was a highly significant difference in gene risk allele frequency between Pakistanis and Caucasians (Northwick Park Heart Study II [NPHSII]) for rs187238 (IL-18), rs1800795 (IL-6), rs1800629 (TNF-alpha), and rs1800871 (IL-10) (p < 0.01). CONCLUSIONS: A cytokine gene score has significant discriminatory ability and potential in the risk prediction of PCAD. Cytokine gene risk allele frequencies differ significantly between Pakistanis and Caucasians supporting the need to develop population-specific gene scores.