Ana Kolaković

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.

miR-155 expression level changes might be associated with initial phases of breast cancer pathogenesis and lymph-node metastasis

BACKGROUND Breast carcinoma is heterogeneous disease. Understanding the process of invasion and metastasis and the selection of the therapy for patients with breast carcinomas still remains difficult. MicroRNAs are powerful gene expression regulators. Because of inconsistent findings, we have analyzed potential difference in miR-155 levels in three breast cancer groups. OBJECTIVES Our goals were to examine miR-155 expression levels in normal tissue, non-invasive and invasive breast carcinomas, and their association with standard clinical and pathological parameters and oncomiR-21, and to investigate the ability of miR-155 to separate invasive breast carcinomas with non-invasive component from pure invasive. METHODS In the group of 40 breast tissue samples, relative expression levels of miR-155 were examined with stem-loop quantitative real-time PCR using TaqMan technology. RESULTS The significant difference among four examined groups of the breast tissue was detected (p = 0.001). In the group of pure invasive tumors, patients with positive nodal status had significantly higher miR-155 levels (p = 0.046). CONCLUSION Our results suggest that miR-155 might be involved in breast cancer pathogenesis and in tumor spreading to the lymph nodes, and that it might be used as biomarker for additional stratification of patients with invasive breast carcinomas with non-invasive component.

Renin-angiotensin system gene polymorphisms as risk factors for multiple sclerosis

The components of renin-angiotensin system, such as angiotensin-converting enzyme (ACE), angiotensin II and angiotensin II receptor type 1 and 2 (AT1R and AT2R), are expressed in the central nervous system and leukocytes and proposed to be involved in the inflammation and pathogenesis of multiple sclerosis (MS). ACE I/D, AT1R 1166A/C and AT2R -1332A/G are functional polymorphisms associated with phenotypes of diverse chronic inflammatory diseases. The aim of this study was to investigate the association between ACE I/D, AT1R 1166A/C and AT2R -1332A/G gene polymorphisms and MS in Serbian population. A total of 470 MS patients and 478 controls participated in the study. Allele-specific polymerase chain reaction (PCR) was performed for genotyping of the ACE polymorphism. The AT1R and AT2R genotyping was done by duplex PCR and restriction fragment length polymorphism analysis. Both ACE homozygotes, II and DD, were significantly overrepresented in MS patients, compared to controls (χ(2) test p=0.03). Neither genotype nor allele frequencies of AT1R 1166A/C polymorphism were significantly different between patients and controls. Significant overrepresentation of AT2R -1332 AA genotype in female patients, compared to female controls, was detected (OR=1.67, 95%CI=1.13-2.49, χ(2) test p=0.01), suggesting that this genotype could be a gender-specific genetic risk factor for MS.

Expression of toll-like receptors 2, 4 and nuclear factor kappa B in mucosal lesions of human otitis: pattern and relationship in a clinical immunohistochemical study.

Objectives: The objectives were to detect and compare the expression of toll-like receptors (TLRs) 2, 4 and nuclear factor kappa B in mucosal lesions of chronic otitis. Methods: Fifty-five tissue samples obtained from children and adults operated on for otitis were investigated by semiquantitative immunohistochemical methods using polyclonal antibodies for TLR 2, 4 and NFkB. Kruskal–Wallis, Mann–Whitney, and Kendall’s tau rank correlation tests were used. Results: Stronger expression of TLR2, 4 was found in inflamed mucosa than in the control for children and adults (TLR2: H = 23.86, P < .001; TLR4: H = 22.80, P < .001) (TLR2: H = 17.53, P < .001; TLR4: H = 11.99, P < .001); in cholesteatoma perimatrix compared to tubotympanic lesions in children (TLR2: H = 11.06, P = .004; TLR4: H = 10.61, P = .005) and adults (TLR2: H = 10.73, P = .013; TLR4: H = 9.65, P = .021). No differences were found in NFkB expression (H = 0.042, P = .99). Significant correlations were found for all pairs of molecules in cholesteatoma and tubotympanic mucosa of adults (TLR2, 4: P = .002, P < .001; TLR2-NfkB: P = .032, P = .021; TLR4-NFkB: P = .035, P = .0013), only TLR4-NFkB in tubotympanic otitis of children (P = .026). Conclusions: Toll-like receptors 2, 4 and NFkB mediate inflammation in cholesteatoma and mucosal lesions of tubotympanic otitis in children and adults. Significant correlations between all pairs of molecules in all samples were detected in adults, but only TLR4-NFkB in children.

The association of ACE I/D gene polymorphism with severe carotid atherosclerosis in patients undergoing carotid endarterectomy

Introduction: The ACE I/D polymorphism was mostly investigated in association with intima-media thickness, rarely with severe atherosclerotic phenotype. Materials and methods: We investigated the association of I/D polymorphism with severe carotid atherosclerosis (CA) (stenosis > 70%) in asymptomatic and symptomatic patients undergoing carotid endarterectomy. The 504 patients subjected to endarterectomy and 492 healthy controls from a population in Serbia were investigated as a case-control study. Results: The univariate logistic regression analysis revealed ACE DD as a significant risk factor for severe CA (odds ratio [OR] = 1.3, 95% confidence interval [CI] 1.0–1.7, p = 0.04). After adjustment for the common risk factors (age, hypertension, smoking, and HDL) ACE was no longer significant. However, we found a significant independent influence of DD genotype on plaque presence in a normotensive subgroup of patients (OR 1.8, CI 1.2–3.0, p = 0.01, corrected for multiple testing). In symptomatic patients D allele carriers were significantly more frequent compared with asymptomatic patients (OR 1.6 CI 1.0–2.6, p = 0.05). Conclusions: Our data suggests that ACE I/D is not an independent risk factor for severe CA. On the other hand, a significant independent genetic influence of ACE I/D appeared in normotensive and symptomatic patients with severe CA. This should be considered in further research toward resolving the complex genetic background of severe CA phenotype.

Gender-Specific Association between Angiotensin II Type 2 Receptor −1332 A/G Gene Polymorphism and Advanced Carotid Atherosclerosis

BACKGROUND The angiotensin II type 2 receptor (AT2R) -1332 A/G polymorphism has been denoted as functional and associated with certain cardiovascular disease phenotypes. However, there are no studies considering the association of this gene polymorphism with carotid atherosclerosis (CA) and cerebrovascular events. Therefore, the aim of our study was to investigate a possible association of the AT2R -1332 A/G polymorphism with the occurrence of carotid plaques (CPs) and history of cerebrovascular insult (CVI) in advanced CA. METHODS The study group included 381 controls and 509 patients with CA consecutively admitted for endarterectomy. Genotyping was determined by polymerase chain reaction-restriction fragment length polymorphism method. The association was analyzed separately for males and females because the AT2R gene is located on the X chromosome. RESULTS The AT2R -1332 GG genotype was associated with the advanced CA in the female study group (recessive model of inheritance, AA+AG versus GG; adjusted odds ratio [OR] = 2.25; 95% confidence interval [CI] 1.17-4.33; P = .01). In the male subgroup of patients with CA, the significant overrepresentation of G/- hemizygote was detected in patients with CVI compared to male patients without this event (crude OR = 2.05, 95% CI 1.20-3.50, P = .008). CONCLUSIONS This study suggests a gender-specific association between the AT2R -1332 A/G polymorphism and the occurrence of CP and the history of CVI in advanced CA, but further replication studies are needed.

Involvement of the Renin‐Angiotensin System in Atherosclerosis

The renin-angiotensin system (RAS) is a well known for its role in the regulation of the blood pressure (BP). Angiotensin II (Ang II), the main mediator of the RAS, may act either, as a systemic molecule or a locally produced factor. Within the vessel wall it has significant proinflammatory role by inducing the oxidative stress, secretion of inflammatory cytokines and adhesion molecules. Ang II could trigger proliferation of vascular smooth muscle cells (VSMC) and its migration to the outer layer of the vessel wall. It could induce the release of matrix metalloproteinase (MMPs), from human VSMC and thus increase susceptibility to rupture of atherosclerotic lesions. Binding of Ang II to AT1R/AT2R could have opposing actions in vascular injury. The ACE2/Ang (1-7)/Mas axis of the RAS also opposes the unfavourable actions of ACE/Ang II/ATR1 axis. Inhibition of RAS could reduce inflammation-associated processes in vasculature, independently of lowering BP. RAS is significantly modulated by the genes coding for this system. Certain genetic variants (SNPs) in the RAS genes have been denoted as the functional ones and have been associated with hypertension, cardiovascular phenotypes and atherosclerosis. Also, the genetic components of the RAS interfere with the regulators of gene expression by microRNAs (miRs).