Tanja Dujic

University of Sarajevo, Bosna-Sarai, Federation of Bosnia and Herzegovina, Bosnia and Herzegovina

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Publications (12)11.03 Total impact

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    ABSTRACT: Common variants in MTNR1B, encoding melatonin receptor 1B, have been recently associated with impaired glucose homeostasis and an increased risk for developing Type 2 diabetes (T2D). In this study we investigated the association of MTNR1B variant rs10830963 with T2D and related quantitative traits in a population from Bosnia and Herzegovina (BH). A total number of 268 subjects were recruited in the study (162 T2D patients and 106 nondiabetic controls). Subjects were genotyped for MTNR1B rs10830963 SNP by using hydrolysis probes. Our data showed that the prevalence of the MTNR1B rs10830963 risk G-allele in BH population was 26%. Furthermore, we demonstrated a significant association of MTNR1B rs10830963 variant with fasting plasma glucose (FPG) levels in nondiabetic subjects. Under the additive genetic model, each variant G-allele was associated with an increased FPG levels of 0.29 mmol/L (95% CI 0.12, 0.46, p=0.001). Strikingly, our results also showed a significant association of this MTNR1B polymorphism with increased glycated hemoglobin (HbA1c) levels in nondiabetic subjects (p=0.040, additive genetic model). An association of the MTNR1B variant rs10830963 with T2D risk was not detected in our cohort. In conclusion, here we have demonstrated the association between the common MTNR1B rs10830963 variation and fasting plasma glucose levels in BH population. Furthermore, the influence of this polymorphism on the HbA1c levels was also shown in this study, further strengthening its role in blood glucose control.
    Experimental and Clinical Endocrinology & Diabetes 04/2014; · 1.56 Impact Factor
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    ABSTRACT: Type 2 diabetes mellitus (T2DM) is a worldwide epidemic with considerable health and economic consequences. T2DM patients are often treated with more than one drug, including oral antidiabetic drugs (OAD) and drugs used to treat diabetic complications, such as dyslipidemia and hypertension. If genetic testing could be employed to predict treatment outcome, appropriate measures could be taken to treat T2DM more efficiently. Here we provide a review of pharmacogenetic studies focused on OAD and a role of common drug-metabolizing enzymes (DME) and drug-transporters (DT) variants in therapy outcomes. For example, genetic variations of several membrane transporters, including SLC2A1/2 and SLC47A1/2 genes, are implicated in the highly variable glycemic response to metformin, a first-line drug used to treat newly diagnosed T2DM. Furthermore, cytochrome P450 (CYP) enzymes are implicated in variation of sulphonylurea and meglitinide metabolism. Additional variants related to drug target and diabetes risk genes have been also linked to interindividual differences in the efficacy and toxicity of OAD. Thus, in addition to promoting safe and cost-effective individualized diabetes treatment, pharmacogenomics has a great potential to complement current efforts to optimize treatment of diabetes and lead towards its effective and personalized care.
    Biochemia Medica 01/2013; 23(2):154-71. · 1.87 Impact Factor
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    ABSTRACT: The enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) catalyzes the conversion of the hormonally inactive cortisone to active cortisol, thus facilitating glucocorticoid receptor activation in target tissues. Increased expression of 11beta-HSD1 in adipose tissue has been associated with obesity and insulin resistance. In this study, we investigated the association of two 11beta-HSD1 gene (HSD11B1) polymorphisms with the metabolic syndrome (MetS) and its characteristics in the Bosnian population. The study included 86 participants: 43 patients diagnosed with MetS and 43 healthy controls. Subjects were genotyped for two HSD11B1 gene polymorphisms: rs846910: G > A and rs45487298: insA, by the high resolution melting curve analysis. Genotype distribution and an influence of genotypes on clinical and biochemical parameters were assessed. There was no significant difference in the mutated allele frequencies for the two HSD11B1 gene polymorphisms between MetS patients and controls. In MetS patients, no significant associations between disease-associated traits and rs45487298: insA were found. Regarding rs846910: G > Avariant, heterozygous patients (G/A) had significantly lower systolic (P = 0.017) and diastolic blood pressure (P = 0.015), lower HOMA-IR index (P = 0.011) and higher LDL-cholesterol levels (P = 0.049), compared to the wild-type homozygotes. In the control group, rs45487298: insA polymorphism was associated with lower fasting plasma insulin levels (P = 0.041), lower homeostasis model assessment insulin resistance (HOMA-IR) index (P = 0.041) and lower diastolic blood pressure (P = 0.048). Significant differences between rs846910: G > A genotypes in controls were not detected. Haplotype analysis confirmed the association of rs45487298: insA with markers of insulin resistance in the control subjects. CONDUSIONS: Our results indicate that a common rs45487298: insA polymorphism in HSD1181 gene may have a protective effect against insulin resistance.
    Biochemia Medica 01/2012; 22(1):76-85. · 1.87 Impact Factor
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    ABSTRACT: Aim: To study the influence of C-reactive protein (CRP) level in the blood, fibrinogen level and general inflammatory syndrome as the predictors of development of secondary fibrosis in patients with pulmonary tuberculosis (TB). Methods: Concentration of CRP, fibrinogen level was measured using immunoturbidimetric methodIncluding criteria was presentation of TB process in both lungs, as the sign of widespread TB process. Results: We examined 85 patients treated in one year. Mean CRP level was 22,6 mg/mL, range 5-245 mg/mL; normal level (up to 8 mg/mL) was measured in 23,4% patients, medium level (9-20 mg/mL) was measured in 31,3% patients, high level (21-50 mg/mL) were measured in 26,2% patients, and in 23,7% patients CRP were higher than 50 mg/mL. Average fibrinogen level in whole group was 6,9 g/L (SD 5,8). Normal level of fibrinogen (up to 4 g/L) were measured in 6,4% of patients; 4,1-1,0 g/L were measured in 24,6% patients, 10,1-20 g/L were measured in 31,1% patient and level more than 20 g/L were measured in 37,9% patients. Using statistic method of partial correlation statistical significane at level p<0,05 was shown between them. Correlation of CRP and fibrinogen level with appearance of fibrosis on X-ray of the lung was shown. Thereafter, closer correlation was shown with fibrinogen and fibrosis than with CRP and fibrosis. Conclusion: Predicted value of CRP and fibrinogen for pulmonary fibrosis was shown in TB patients. So, attenuation of fibrosis development, possible with antifibroblastic activity of pentoxyphyllin, should be taken in consideration, for prevention of widespread development of lung fibrosis in these patients.
    European Respiratory Society - Annual Congress 2011, Amsterdam, Netherlands; 09/2011
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    ABSTRACT: N-acetyltransferase 2 (NAT2) is a drug-metabolizing enzyme, which is genetically variable in human populations. Polymorphisms in the NAT2 gene have been associated with drug efficacy and toxicity as well as disease susceptibility. Recently, an association of NAT2 gene variation with risk of type 2 diabetes mellitus (T2DM) has been suggested. This is the first study performed in a population from Bosnia and Herzegovina (BH) in which the frequency of two common NAT2 polymorphisms, 341T>C (NAT2*5) and 590G>A (NAT2*6) was determined in diabetic patients. The frequency of the NAT2*5 (341T>C) and NAT2*6 (590G>A) polymorphisms was analyzed by employing TaqMan SNP Genotyping Assays (Applied Biosystems) in a group of 63 patients with T2DM and 79 nondiabetic subjects. Our data demonstrated that the frequencies of NAT2*5 (341T>C) and NAT2*6 (590G>A) polymorphisms in BH population were in line with the Caucasians genotype data. The NAT2*5 and NAT2*6 alleles were in high linkage disequilibrium (D' = 0.969). Strinkingly, there was a significant difference in genotype frequencies for NAT2*5 (p <0.05) and NAT2*6 (p <0.001) polymorphisms between diabetic and nondiabetic subjects. NAT2*5 polymorphism was associated with 2.4-fold increased risk for developing T2DM (adjusted OR = 2.40, 95% CI = 1.10-5.25, p = 0.028). On the contrary, NAT2*6 variant significantly decreased by 5-fold susceptibility to the disease (adjusted OR = 0.20, 95% CI = 0.09-0.43, p <0.001). Our data demonstrated that NAT2 genetic variation appeared to be an important risk factor in development of T2DM.
    Archives of medical research 05/2011; 42(4):311-7. · 1.88 Impact Factor
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    ABSTRACT: Differences in the frequency of distribution of the cytochrome P450 (CYP) allelic variants have been demonstrated between distinct ethnic groups, contributing to observed interindividual variation in drug response. In this study we determined, for the first time, prevalence of the common allelic variants of the polymorphic CYP enzymes, CYP3A4*1B and CYP3A5*3, in the population of Bosnia and Herzegovina (BH). Genomic DNA was extracted from blood samples collected from 140 unrelated subjects. A real-time PCR was used for the detection of CYP polymorphisms, with the application of the specific TaqMan SNP Genotyping Assay (Applied Biosystems) for CYP3A5*3, while CYP3A4*1B was genotyped by high-resolution melting analysis. Our results have shown that the distribution of CYP3A4*1B and CYP3A5*3 alleles was in line with the data reported in European Caucasians. We confirmed that CYP3A4*1B mutant allele is rare in Caucasians, being present in only 5.1% individuals. However, CYP3A5*3 polymorphism was found to be predominant in the Bosnian population with an incidence of 94%, similarly to other European populations tested so far. Interestingly, we have demonstrated a strong linkage disequilibrium between CYP3A5*3 and CYP3A4*1B alleles. No significant difference in allele frequencies for CYP3A4*1B and CYP3A5*3 has been shown between male and female subjects participating in our study. Our data demonstrated the high prevalence of CYP3A5*3 allele in Bosnian population, indicating significance of analysis of CYP3A5 and CYP3A4 polymorphisms and corresponding allele frequencies in specific ethnic groups. Importantly, results of this study may lead to translation of pharmacogenetics and individualized therapeutic approach in current clinical practices in BH.
    Medicinski glasnik 02/2011; 8(1):84-9. · 0.20 Impact Factor
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    ABSTRACT: Lipin 1 is a recently discovered multifunctional protein involved in the metabolism of lipids, while PPARgamma is involved in adipocyte differentiation, and regulation of lipid metabolism. Up to now, LPIN1 and PPARG gene polymorphisms have been associated with type 2 diabetes, metabolic syndrome, and central obesity. In this study, we hypothesized that genetic variants within LPIN1 and PPARG genes were associated with traits of metabolic syndrome. Correlation between biochemical parameters (including but not limited to, glucose, HbA1c, insulin levels, HDL and LDL cholesterol, triglycerides, serum proteins, liver enzymes) and frequency of polymorphisms in LPIN1 (rs11693809 and rs2716610) and PPARG gene (rs10865710, rs3856806 and rs1801282), was tested in this study. The study included 70 patients diagnosed with metabolic syndrome and type 2 diabetes. Two polymorphisms of LPIN1 gene (rs11693809 and rs2716610), and three polymorphisms of PPARG gene (rs10865710, rs385806 and rs1801282) were analyzed by real time PCR and conventional PCR-RFLP methods. Our analysis revealed correlation between insulin levels and rs11693809 LPIN1 polymorphism in diabetic patients. Also the results of this study showed an association of rs10865710 and rs385806 polymorphism of PPARG with HDL cholesterol and LDL plus total cholesterol levels, respectively. These data reflect an association of analyzed PPARG and LPIN1 gene polymorphisms with values of insulin, HDL, LDL and total cholesterol witch indicates an important role of these genes in lipid metabolism and pathogenesis of type 2 diabetes and metabolic syndrome.
    Medicinski glasnik 02/2011; 8(1):76-83. · 0.20 Impact Factor
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    ABSTRACT: Polymorphisms in HSD11B1, the gene encoding 11β-hydroxysteroid dehydrogenase type 1 enzyme, have been associated with obesity, metabolic syndrome, and type 2 diabetes. In this study, we present an optimized high-resolution melting (HRM) method for genotyping two common polymorphisms of the HSD11B1 gene: rs846910: G>A and rs45487298: insA. One hundred DNA samples from patients with polycystic ovary syndrome and healthy controls were genotyped by HRM. The results were compared with those obtained with classic polymerase chain reaction followed by restriction fragment length polymorphism analysis. Various approaches were used during HRM specificity optimization. With the optimized method, genotyping accuracy of 100% was achieved. HRM analysis is a fast, simple, and cost-effective method compared with the alternative genotyping approaches. The work required for optimizing the method (improvement of specificity) is minor compared to the advantages.
    Genetic Testing and Molecular Biomarkers 01/2011; 15(1-2):43-9. · 1.44 Impact Factor
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    ABSTRACT: This is the first study performed in population from Bosnia & Herzegovina (BH), in which we analysed a significance of genetic variations in drug-metabolising enzyme, cytochrome P450 (CYP), in pathogenesis of Type 2 diabetes. We have determined allele frequencies for CYP2C9*2, CYP2C19*2, and CYP2D6*4 in diabetic patients and nondiabetic controls. Genomic DNA was extracted from blood samples collected from 37 diabetic and 44 nondiabetic subjects. A real-time polymerase chain reaction was used for the detection of specific CYP polymorphisms, with the application of the specific TaqMan® SNP genotyping tests (Applied Biosystems). Interestingly, results from this study have demonstrated that frequencies of CYP2C19*2 and CYP2D6*4 variants were in line, while frequency of CYP2C9*2 polymorphism seemed to be lower in this sample of BH population as compared to the Caucasians genotype data. Furthermore, no significant difference in allele frequencies for CYP2C9*2, CYP2C19*2, and CYP2D6*4 was demonstrated between diabetic and nondiabetic subjects. Thus, results form this study seem to indicate no relationship between CYP2C9, CYP2C19, and CYP2D6 genotype and diabetes susceptibility in Bosnian population. This in part may reflect a limited study population included in our study and would require larger cohorts to reveal potential relationships between analysed CYP genetic variants and diabetes risk. In addition, it would be pertinent to further explore possible effects of CYP genetic variations on therapeutic and adverse outcomes of oral antidiabetics, which might be the key in optimising therapy for individual patient with Type 2 diabetes.
    Bosnian journal of basic medical sciences / Udruzenje basicnih mediciniskih znanosti = Association of Basic Medical Sciences 11/2010; 10(4):287-91. · 0.50 Impact Factor
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    ABSTRACT: Recent studies have introduced serum uric acid (UA) as a potential risk factor for developing diabetes, hypertension, stroke, and cardiovascular diseases. The value of elevated levels of UA in serum as a risk factor for diabetes development is still under scrutiny. Recent data suggest that clearance of UA is being reduced with increase in insulin resistance and UA as a marker of prediabetes period. However, conflicting data related to UA in serum of patients with Type 2 diabetes prompted us to study the urine/serum ratio of UA levels (USRUA) in these patients and healthy controls. All subjects included in the study were free of evidence of hepatitis B or C viral infection or active liver and kidney damage. Patients receiving drugs known to influence UA levels were also excluded from this study. Analysis of glucose and uric acid were performed on Dade Behring analyzer using standard IFCC protocols. Interestingly, our data demonstrated about 2.5 fold higher USRUA values in diabetic patients as compared to control subjects. Furthermore, there was a trend of correlation of USRUA value with the blood glucose levels in diabetic patients, which was more prominent in diabetic men than in women. With aging, levels of uric acid increased in serum of diabetic patients, and this effect was also more profound in male than in female diabetics. In conclusion, this study showed significantly elevated USRUA levels in patients with Type 2 diabetes, a negative USRUA correlation with the blood glucose levels in diabetic patients, and an effect of sex and age on the uric acid levels. Since literature data suggest a strong genetic effect on UA levels, it would be pertinent to perform further, possibly genetic studies, in order to clarify gender and ethnic differences in UA concentrations.
    Bosnian journal of basic medical sciences / Udruzenje basicnih mediciniskih znanosti = Association of Basic Medical Sciences 02/2010; 10(1):54-9. · 0.50 Impact Factor
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    ABSTRACT: Numerous studies conducted on acetylsalicylic acid (ASA, aspirin) confirmed that ASA inhibits proliferation and induces apoptosis in various types of human cells. Therefore, it was of interest to examine possible effects of different concentrations of ASA on viability and proliferation of lymphocytes in the cell culture. After separation from blood, lymphocytes were suspended in RPMI 1640 medium and cultured at 37 degrees C. Solution of ASA was added to cultures after 24 h, in final concentrations of 1, 3 and 5 mmol/l. After 48 h, proliferative response was evaluated by WST-1 assay. Significant difference in viability between controls and cell cultures treated with ASA in three different concentrations was observed (p<0.01). Percents of viable cells in cultures after application of 1, 3 and 5 mmol/l ASA were 9.9%, 2.5% and 16.9% (compared to controls), respectively. To determine whether this cytotoxic effect was result of induction of apoptosis, DNA from cell cultures was isolated and subjected to agarose gel electrophoresis. Fragmentation of DNA was not detected, excluding apoptosis as possible cause of cytotoxic effects. Addition of ASA caused change of initial extracellular pH value for each treated culture. After addition of 1 mmol/l ASA, pH of culture was 7.19, after 3 mmol/L, 6.99 and after addition of 5 mmol/l solution, pH was 6.75. Decreased lymphocyte viability could be attributed to either the effects of the added substance or possible further acidification of cell cultures during three days of incubation.
    Bosnian journal of basic medical sciences / Udruzenje basicnih mediciniskih znanosti = Association of Basic Medical Sciences 08/2008; 8(3):210-3. · 0.50 Impact Factor
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    ABSTRACT: Diabetes mellitus can be looked upon as an array of diseases, all of which exhibit common symptoms. While pathogenesis of IDDM (insulin dependant diabetes mellitus) is well understood, the same is not true for diabetes mellitus type II. In the latter case, relative contribution of the two factors (insulin resistance or decreased insulin secretion) varies individually, being highly increased in peripheral tissues and strictly dependant on insulin for glucose uptake. Moreover, in patients with diabetes mellitus type II, disbalance at the level of regulation of glucose metabolism as well as lipid metabolism has been noted in skeletal muscles. It is normal to assume that in this type of diabetes, these changes are reflected at the level of total activity of enzyme creatine kinase. This experimental work was performed on a group of 80 regular patients of Sarajevo General Hospital. Forty of those patients were classified as patients with diabetes type I and forty as patients with diabetes type II. Each group of patients was carefully chosen and constituted of equal number of males and females. The same was applied for adequate controls. Concentration of glucose was determined for each patient with GOD method, while activity of creatine kinase was determined with CK-NAC activated kit. Statistical analysis of the results was performed with SPSS software for Windows. Obtained results point out highly expressed differences in enzyme activity between two populations examined. Changes in enzyme activity are more expressed in patients with diabetes type II. Positive correlation between concentration of glucose and serum activity of the enzyme is seen in both categories of diabetic patients which is not the case for the patients in control group. At the same time, correlation between age and type of diabetes does exist . This is not followed at the level of enzyme activity or concentration of glucose.
    Bosnian journal of basic medical sciences / Udruzenje basicnih mediciniskih znanosti = Association of Basic Medical Sciences 09/2006; 6(3):5-9. · 0.50 Impact Factor