Dragan Alavantić

Angiotensin II type 1 receptor gene polymorphism and essential hypertension in Serbian population

Essential hypertension is considered to be a multifactorial trait resulting from the combined influence of environmental and genetic determinants. Due to the controversial results about the role of the ATR1 gene locus in hypertension and understanding that ethnic origin should be carefully considered in studying the association between gene polymorphism and disease etiology, we investigated the role of A1166C polymorphism in Serbian hypertensives. A total of 298 subjects, 100 hypertensive and 198 normotensive, age- and sex-matched controls, were included in this study. All subjects were genotyped for the A1166C polymorphism in ATR1 gene using allele-specific PCR-based technique. There were significant differences in both allele and genotype frequencies between hypertensive and normotensive male subjects (p<0.05). There is significant association between hypertension and CC genotype (CC vs. AC+AA OR=2.56, p=0.04) in the males only. These results suggest that a genetic variant of the ATR1 gene locus influences the risk of essential hypertension in the sex-specific manner in the Serbian population.

Association of MMP-3 5A/6A gene polymorphism with susceptibility to carotid atherosclerosis

OBJECTIVES Stromelysin-1 (MMP-3) as a key member of metalloproteinase family could have an important role in atherogenesis. The 5A/6A polymorphism in the promoter of MMP-3 gene affects the level of MMP-3 gene expression. We assessed whether the MMP-3 promoter low- and high-activity genotypes are related to susceptibility for carotid atherosclerosis (CA) in Serbian population. DESIGN AND METHODS The study group of case-control design consisted of 515 participants. The 265 patients with ultrasonographic evidence of carotid plaque presence were recruited for the study. The 5A/6A polymorphism was typed by RFLP-PCR. RESULTS There was significantly higher prevalence of genotypes containing 6A allele in the patients with CA compared to controls (p<0.05). The model of inheritance with the dominant effect of 6A allele gave elevated and significant OR for carotid atherosclerosis (adjusted OR 2.35, CI=1.0-5.5, p=0.048). CONCLUSIONS Subjects carrying genotypes with 6A allele had significantly higher susceptibility to carotid atherosclerosis.

Association of polymorphisms in CTLA-4, IL-1ra and IL-1β genes with multiple sclerosis in Serbian population

We have investigated separate as well as combined influence of IL-1beta TaqI, IL-1ra VNTR and CTLA-4 + 49 A/G polymorphisms on susceptibility, clinical course and progression of MS in 162 Serbian patients. We found significant independent relative risk for MS susceptibility in noncarriers of IL-1ra allele 2 (OR = 2.2, CI = 1.3-3.7, p = 0.003) and CTLA-4 + 49 AA genotype (OR = 2.0, CI = 1.2-3.5, p = 0.01) as well as their combined effect (OR = 4.4, CI = 2.0-9.7, p = 0.0003). Our result supports the significant and combined effect of IL-1ra VNTR and CTLA-4 polymorphisms on MS justifying the need for further haplotype analysis in different populations.

Study of apoB gene signal peptide insertion/deletion polymorphism in a healthy Serbian population: no association with serum lipid levels

The apolipoprotein B (apoB) signal peptide polymorphism was studied in unrelated healthy individuals. A total of 232 women and 222 men were analyzed separately. The relative frequencies of Del allele in women and men were 0.42 and 0.37, respectively. More heterozygous individuals were detected in comparison with other populations, using a modified silver staining method on polyacrylamide gel for visualization of Ins and Del alleles. There was no statistically significant difference in mean lipid levels adjusted for age, BMI, smoking habit and blood pressure between the three Ins/Del genotypes in both samples (ANOVA). Therefore, no differences were shown in the genotype frequency distribution throughout the lipid quartiles.

Association of MMP-8 promoter gene polymorphisms with carotid atherosclerosis: Preliminary study

OBJECTIVE Matrix metalloproteinases (MMPs) are involved in the remodeling of the extracellular matrix in the arterial wall. Collagen I is associated with vascular smooth muscle cell (VSMC) migration and monocyte differentiation. MMP-8 is expressed in atherosclerotic plaque and preferentially cleaves collagen type I. The aim of this study was to investigate the associations of two MMP-8 promoter polymorphisms, rs11225395 (-799C/T) and rs1320632 (-381 A/G), with carotid plaque occurrence, and the influence of these polymorphisms on MMP-8 mRNA expression in plaque tissue. METHODS The study included a total of 766 participants: 277 controls and 489 patients with carotid atherosclerosis undergoing endarterectomy. The two investigated polymorphisms were genotyped by PCR-RFLP. The gene expression analysis was performed by real-time PCR. RESULTS In females only, a significantly higher frequency of the -381G allele was found in patients with carotid atherosclerosis compared to controls (OR, 1.7; 95% CI 1.1-2.9; p = 0.001). Significant up-regulation of MMP-8 gene expression was observed in patients carrying the -381G allele compared to those with the AA genotype (mean factor, 3.54; S.E. range, 0.643-19.551; p = 0.007). Carotid plaque tissue of the haplotype G(-381)T(-799) showed a significantly higher mRNA level compared with the reference A(-381)C(-799) haplotype (p = 0.003). CONCLUSION Our preliminary results indicate that MMP-8 -381A/G and -799C/T gene polymorphisms could be risk factors for carotid atherosclerosis. Further validation and functional studies are needed to establish the potential regulatory role of these polymorphisms and their impact on susceptibility to carotid atherosclerosis.

Plasma levels of matrix metalloproteinase-8 in patients with carotid atherosclerosis.

Matrix metalloproteinases (MMPs) are involved in the remodeling of the extracellular matrix (ECM) in the arterial wall during atherogenesis. Collagens are the most abundant proteins in the ECM. MMP‐8 is expressed by cells associated with the development of the atherosclerotic plaque. It cleaves collagen type I three times more potently than two other interstitial collagenases MMP‐1 and MMP‐13. The aim of this study was to investigate whether plasma MMP‐8 values are associated with occurrence of carotid plaque (CP) and possible correlations with clinical and biochemical parameters in carotid atherosclerosis (CA) patients. Total plasma MMP‐8 levels were quantified by ELISA in 63 patients with ultrasonographic evidence of CP presence and 12 controls. Plasma MMP‐8 values were significantly higher in patients with CA compared with controls (median 23.36 ng/ml vs. 13.02 ng/ml, P<0.001) but they did not differ significantly according to gender, smoking and hypertensive status, associated diseases, and use of statins. Statistically significant positive correlations were observed between MMP‐8 plasma values and C reactive protein (r=0.41, P=0.001), urea (r=0.50, P<0.001), aspartate transaminase (r=0.48, P=0.001), and creatinine levels (r=0.38, P=0.006). These results suggest association of MMP‐8 plasma levels with occurrence of CP and correlation with certain biochemical markers. J. Clin. Lab. Anal. 24:246–251, 2010.

Matrix metalloproteinase-9 -1562 C/T gene polymorphism in Serbian patients with multiple sclerosis.

Matrix metalloproteinase-9 (MMP-9) is suggested to play a role in MS by mediating T cell migration across subendothelial basement membrane and by contribution to myelin breakdown. We studied the association of MMP-9 -1562 C/T gene polymorphisms with MS susceptibility and severity in 187 patients from Serbia. The significant decrease in T allele carriership (p = 0.01), was found in female MS patients. In addition, a trend toward lower MSSS in T allele carriers was noticed (CC, mean 5.7 +/- 2.5 vs. CT+TT, mean 4.9 +/- 2.5). Further studies in different populations are needed to resolve the potential influence of MMP-9 gene polymorphism on MS.

Lipoprotein lipase: A bioinformatics criterion for assessment of mutations as a risk factor for cardiovascular disease

Lipoprotein lipase (LPL) is a key enzyme in lipid metabolism. Decrease of the LPL enzymatic activity leads to elevated triglycerides (TG) and reduced high‐density lipoprotein (HDL‐C levels), both risk factors for cardiovascular disease (CVD). Therefore, mutations, which decrease the LPL activity, may confer susceptibility to CVD. Here, the informational spectrum method (ISM), a virtual spectroscopy method for structure/function analysis of nucleotide and protein sequences, is applied for identification of evolutionary highly conserved information encoded by the primary structure of LPL. It was demonstrated that mutations, which alter the LPL enzymatic activity also alter this information. On the basis of this finding, an efficient and simple bioinformatics criterion for assessment of the pathogenic effect of LPL nonsynonymous single nucleotide substitution as a risk factor of CVD has been proposed. Proteins 2008.

Matrix metalloproteinase-1 promoter genotypes and haplotypes are associated with carotid plaque presence.

OBJECTIVES Matrix metalloproteinase (MMP)-1 degrades fibrillar collagens suggesting important role in vascular remodeling. Data about MMP-1 promoter polymorphisms and carotid atherosclerosis (CA) are scarce. The aim of this study was to evaluate association of MMP-1 genotypes/haplotypes with carotid plaque (CP) presence in Serbian population. DESIGN AND METHODS Study enrolled a total of 702 participants: 274 controls and 428 consecutive patients with CA who underwent carotid endarterectomy. MMP-1 polymorphisms -1607 1G/2G, -519 A/G and -340 T/C were genotyped by PCR and RFLP methods. RESULTS Individuals carrying MMP-1 -1607 2G allele had significantly increased allele dose-dependent risk for CP presence (1G1G vs. 1G2G vs. 2G2G; OR=1; OR=1.87 95% CI 1.29-2.07; OR=3.49 95% CI 1.67-7.30, p=0.0009, respectively). Compared to the referent haplotype 2G(-1607)-T(-340)-A(-519), the haplotypes 1G(-1607)-T(-340)-A(-519), 1G(-1607)-T(-340)-G(-519) and 2G(-1607)-C(-340)-A(-519) had statistically significant protective effect on CP presence (OR=0.41, 95% CI 0.29-0.81, p=0.01; OR=0.56, 95% CI 0.44-0.89, p=0.01; OR=0.43, 95% CI 0.27-0.86, p=0.02, respectively). CONCLUSIONS MMP-1 -1607 G/2G polymorphism solely and specific haplotypes of three analyzed promoter polymorphisms are significantly and independently associated with occurrence of CP. Replication studies in other populations are needed.

Expression profiling of the AT2R mRNA in affected tissue from children with CAKUT

OBJECTIVES Congenital anomalies of the kidney and urinary tract (CAKUT) are common causes of chronic renal failure in children. The angiotensin II receptor type 2 (AT2R) is one of proposed candidate genes for CAKUT, but the expression was never explored in humans. The aim was to establish the AT2R gene expression in human CAKUT concerning -1332A/G polymorphism, which might affect alternative splicing. DESIGN AND METHODS Forty-eight patients with CAKUT constitute the basis of this study. Genotyping for -1332A/G, RT-PCR for AT2R gene expression and confirmation sequencing were performed. RESULTS The expression of Ex 1/2/3 and Ex 1/3 transcript splice variants of the AT2R mRNA were detected in human CAKUT tissue. The pattern was observed independently of A to G transition. CONCLUSIONS The expression of AT2R mRNA in human CAKUT was established for the first time and was not affected by -1332A/G polymorphism in children with CAKUT.