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Dive into the research topics where Marija Pljesa-Ercegovac is active.

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Featured researches published by Marija Pljesa-Ercegovac.


Nature Reviews Urology | 2009

Glutathione S -transferases in kidney and urinary bladder tumors

Tatjana Simic; Ana Savic-Radojevic; Marija Pljesa-Ercegovac; Marija Matic; Jasmina Mimic-Oka

Exposure to potential carcinogens is an etiologic factor for renal cell carcinoma (RCC) and transitional cell carcinoma (TCC) of the urinary bladder. Cytosolic glutathione S-transferases (GSTs) are a superfamily of enzymes that protect normal cells by catalyzing conjugation reactions of electrophilic compounds, including carcinogens, to glutathione. Some GST enzymes possess antioxidant activity against hydroperoxides. The most well characterized classes have been named alpha (GSTA), mu (GSTM), pi (GSTP) and theta (GSTT); each of these classes contains several different isoenzymes. Several types of allelic variation have been identified within classes, with GSTM1-null, GSTT1-null and GSTP1-Ile105/Ile105 conferring impaired catalytic activity. The effects of GSTM1 and GSTT1 polymorphism on susceptibility to RCC depend on exposure to specific chemicals. Individuals with the GSTM1-null genotype carry a higher risk for TCC. The roles of GSTT1 polymorphism in TCC and GSTP1 polymorphisms in both cancers are still controversial. During kidney cancerization, expression of GSTA isoenzymes tends to decrease, which promotes the pro-oxidant environment necessary for RCC growth. In the malignant phenotype of TCC of the bladder, upregulation of various GST classes occurs. Upregulation of GSTT1 and GSTP1 might have important consequences for TCC growth by providing a reduced cellular environment and inhibition of apoptotic pathways.


Nephrology Dialysis Transplantation | 2013

Glutathione S-transferase A1, M1, P1 and T1 null or low-activity genotypes are associated with enhanced oxidative damage among haemodialysis patients

Sonja Suvakov; Tatjana Damjanovic; Aleksandra Stefanović; Tatjana Pekmezovic; Ana Savic-Radojevic; Marija Pljesa-Ercegovac; Marija Matic; Tatjana Djukic; Vesna Coric; Jovana Jakovljevic; Jasmina Ivanisevic; Steva Pljesa; Zorana Jelic-Ivanovic; Jasmina Mimic-Oka; Nada Dimkovic; Tatjana Simic

BACKGROUND Increased oxidative stress is a hallmark of end-stage renal disease (ESRD). Glutathione S-transferases (GST) are involved in the detoxification of xenobiotics and protection of oxidative damage. We hypothesized that genetic polymorphism in antioxidant enzymes GSTA1, GSTM1, GSTP1 and GSTT1 is more frequent in ESRD and modulates the degree of oxidative stress in these patients. METHODS GSTA1, GSTM1, GSTP1 and GSTT1 genotypes were determined in 199 ESRD patients and 199 age- and gender-matched controls. Markers of protein and lipid oxidative damage [thiol groups, carbonyl groups, advanced oxidative protein products, nitrotyrosine, malondialdehyde (MDA) and MDA adducts], together with total oxidant status and pro-oxidant-antioxidant balance were determined. RESULTS Individual GST polymorphisms influence vulnerability to both protein and lipid oxidation, with GSTM1-null gene variant having the most pronounced effect. Furthermore, a strong combined effect of null/low-activity GSTM1, GSTT1, GSTA1 and GSTP1 genotypes in terms of susceptibility towards oxidative and carbonyl stress was found in ESRD patients. When patients were stratified according to GSTM1 and GSTT1, the highest oxidant damage was noted in those with the GSTM1-null/GSTT1-null genotype. The observed effect was even stronger in patients with the third low-activity GSTP1 or GSTA1 genotype. Finally, the level of oxidative and carbonyl stress was most pronounced in the subgroup of patients with all four null or low-activity GSTM1, GSTT1, GSTP1 and GSTA1 genotypes. CONCLUSIONS According to the GST genotype, ESRD patients may be stratified in terms of the level of oxidative and carbonyl stress that might influence cardiovascular prognosis, but could also improve efforts towards individualization of antioxidant treatment.


Renal Failure | 2005

Evaluation of Oxidative Stress after Repeated Intravenous Iron Supplementation

Jasmina Mimic-Oka; Ana Savic-Radojevic; Marija Pljesa-Ercegovac; Marija Opacic; Tatjana Simic; Nada Dimkovic; Dragan Simic

Parenteral iron has been recommended for the treatment of iron deficiency in the majority of maintenance hemodialyzed (HD) patients. However, iron supplementation and consequent over saturation of transferrin and high iron levels, may aggravate oxidative stress already present in these patients. This study aimed to further clarify the role of repeated intravenous iron therapy as a supplementary cause of oxidative stress in HD patients. Markers of free radical activities (carbonyl reactive derivatives, CRD, thiol groups, SH, malondialdehyde, MDA) and antioxidant enzyme activities (superoxide dismutase, SOD and glutathione peroxidase, GPX) were determined in plasma and red blood cells (RBC) of 19 hemodialysis patients given a total iron dose of 625 mg (ferrogluconat, Ferrlecit, 62.5 mg). Blood samples were taken before the first and after the last dose of iron. Twenty apparently normal subjects served as healthy controls. Before iron treatment, HD patients exhibited increased concentrations of MDA and CRD in plasma and red blood cells, accompanied with impaired antioxidant capacity. All patients responded to iron therapy with a significant increase in their serum ferritin, serum iron, hemoglobin, and red blood cells levels. However, iron treatment resulted in enhanced oxidative stress in plasma of HD patients, since significant increase in plasma MDA and CRD concentrations, together with a decrease in nonprotein SH groups levels were detected. Supplementation with iron did not significantly influence plasma SOD and GPX activities, nor did any of the red blood cell parameters tested. Our data show that, despite improvement in hematological parameters, an increase in iron stores due to supplementation could also contribute to increased free radical production in HD patients.


Urologic Oncology-seminars and Original Investigations | 2013

GSTA1, GSTM1, GSTP1, and GSTT1 polymorphisms and susceptibility to smoking-related bladder cancer: A case-control study

Marija Matic; Tatjana Pekmezovic; Tatjana Djukic; Jasmina Mimic-Oka; Dejan Dragicevic; Biljana Krivic; Sonja Suvakov; Ana Savic-Radojevic; Marija Pljesa-Ercegovac; Cane Tulic; Vesna Coric; Tatjana Simic

OBJECTIVES Glutathione S-transferases (GSTs) are a family of enzymes involved in detoxification. Genes encoding for GSTA1, GSTM1, GSTP1, and GSTT1 proteins are polymorphic, which can result in complete or partial loss of enzyme activity. Previous studies have associated polymorphisms of GSTA1, GSTM1, and GSTP1 genes with a higher risk of bladder cancer, but this is still controversial. Potential role of GSTA1 polymorphism in susceptibility to bladder cancer in Whites is lacking. We examined association between GSTA1, GSTM1, GSTP1, and GSTT1 gene variants and bladder cancer risk and evaluated whether they were modified by smoking. MATERIALS AND METHODS A hospital-based case-control study recruited 201 incidence cases and 122 age-matched controls. Deletion polymorphism of GSTM1 and GSTT1 was identified by polymerase chain reaction method. Single nucleotide polymorphism of GSTA1 and GSTP1 was identified by restriction fragment length polymorphism method. Uniconditional multivariate logistic regression was applied to model association between genetic polymorphisms and bladder cancer risk, as well as effect modification by smoking. RESULTS No significant difference was observed in the distributions of GSTM1, GSTT1, GSTA1, and GSTP1 gene variants between patients and controls. None of the examined polymorphisms was significantly associated with bladder cancer risk independently. The results of gene-smoking interaction analyses indicated a significant combined effect of smoking and all common GST polymorphisms tested (P for trend = 0.001). However, the most significant effect on bladder cancer risk was observed in smokers carrying lower activity GSTA1-AB/BB and GSTM-null genotype (OR = 3.5, P < 0.05) compared with GSTA1-AA and GSTM1-active non-smokers. Overall, the risk observed did not significantly differ with respect to quantity of cigarettes smoked. However, heavy smokers with GSTM1-null genotype had 2 times higher risk of bladder cancer than GSTM1-null light smokers (OR = 4.8 vs. OR = 2.0) when GSTM1-active non-smokers served as reference group. Smokers carrying both GSTM1-null and GSTA1-AB + BB genotypes exhibited the highest risk of bladder cancer (OR = 2.00, P = 0.123). CONCLUSIONS Null or low-activity genotypes of the GSTA1, GSTM1, GSTT1, and GSTP1 did not contribute independently towards the risk of bladder cancer in our patients. However, in association with smoking, both low activity GSTA1 and GSTM1-null genotype increase individual susceptibility to bladder cancer.


Urologic Oncology-seminars and Original Investigations | 2008

Altered antioxidant capacity in human renal cell carcinoma: role of glutathione associated enzymes.

Marija Pljesa-Ercegovac; Jasmina Mimic-Oka; Dejan Dragicevic; Ana Savic-Radojevic; Marija Opacic; Steva Pljesa; Radoslav Radosavljevic; Tatjana Simic

PURPOSE We aimed to discern the role of glutathione (GSH) associated enzymes in maintaining high GSH levels in renal cell carcinoma (RCC) of the clear cell type and analyze RCC enzyme antioxidant capacity. Since changes in cellular redox balance in RCC might also be related to alterations of glutathione S-transferase (GST) phenotype, GST class alpha and pi expression was also explored. METHODS AND MATERIALS Human kidney specimens of tumor and distant nontumor regions were obtained from 15 patients with RCC at the time of surgery. The activities of GSH-replenishing enzymes, gamma-glutamylcysteine synthetase (gamma-GCS), gamma-glutamyl transferase (gamma-GT), and glutathione reductase (GR), as well as the activities of antioxidant enzymes glutathione peroxidase (GPX) and catalase (CAT) were determined spectrophotometrically. GST alpha and pi class expression was determined by immunoblot. RESULTS In the course of renal cancerization, significant changes appear in the activities of GSH-replenishing and antioxidant enzymes. The activity of the key enzyme of GSH synthesis, gamma-GCS, is up-regulated (P < 0.001), while the activities of gamma-GT and GR are down-regulated in renal tumors compared to nontumor tissue (P < 0.001 and P < 0.05, respectively). Activities of GPX and CAT were also down-regulated (P < 0.001 and P < 0.05, respectively) in RCC. Changes in enzyme antioxidant capacity in RCC were associated with decreased GST class alpha (P < 0.001) and unchanged GST pi expression at the protein level. CONCLUSIONS Changes in redox status in RCC as a consequence of decreased enzyme antioxidant capacity, together with altered GST alpha expression, may be important factors in development and tumor growth. The up-regulation of gamma-GCS and high levels of GSH in RCC may be an attempt to limit injury caused by oxidative stress.


Urologic Oncology-seminars and Original Investigations | 2011

Enhanced GSTP1 expression in transitional cell carcinoma of urinary bladder is associated with altered apoptotic pathways

Marija Pljesa-Ercegovac; Ana Savic-Radojevic; Dejan Dragicevic; Jasmina Mimic-Oka; Marija Matic; Tatjana Sasic; Tatjana Pekmezovic; Aleksandar Vuksanovic; Tatjana Simic

OBJECTIVES Glutathione S-transferase P1 (GSTP1) provides an important link between activity of regulatory stress kinases and apoptotic pathways. It can be hypothesized that up-regulated GSTP1, in TCC, might enhance apoptosis inhibition. We aimed to establish whether relationship between GSTP1 expression and executive (pro-caspase 3, cleaved caspase 3) and regulatory (Bcl-2) apoptotic pathways in TCC exists. MATERIALS AND METHODS Samples were obtained from 84 TCC patients (41 consecutive patient with muscle noninvasive and 43 consecutive patients with muscle invasive TCC tumors), who underwent surgery at the Institute of Urology and Nephrology, Clinical Centre of Serbia, during 2006 and 2007. Expression of GSTP1, pro-caspase 3 (CPP32), and Bcl-2, as well as cleaved caspase-3 labeling index (LI) were determined by immunocytochemistry. Levels of expression were correlated with tumor stage, grade, and invasiveness. RESULTS GSTP1 protein expression was demonstrated in all tumor samples examined. According to GSTP1 status, all tumors were divided into groups with low, moderate, or high GSTP1 status. Expression of CPP32 and cleaved caspase 3 was positive in 80% of TCC patients. Their levels differed significantly between groups with various GSTP1 expression (P < 0.05), with the lowest CPP32 expression and cleaved caspase 3 LI in tumors with high GSTP1 status. Moreover, significant negative correlation was found between GSTP1 level and cleaved caspase 3 LI (r = -0.459, P = 0.041). The positive rate of Bcl-2 protein expression was 48%. Most of the Bcl-2 positive patients exhibited at the same time high GSTP1 positivity (P = 0.078). Significant association with tumor grade and stage was found for all examined parameters except for CPP32 regarding tumor grade. CONCLUSIONS Based on results obtained, we conclude that enhanced GSTP1 expression in TCC of urinary bladder is associated with altered apoptotic pathways. Molecular interplay between GSTP1 and members of apoptotic cascade might, at least partially, play a role in development of invasive characteristics of TCC.


Redox Report | 2008

Markers of oxidative damage in chronic heart failure: role in disease progression

Slavica Radovanovic; Mirjana Krotin; Dragan Simic; Jasmina Mimic-Oka; Ana Savic-Radojevic; Marija Pljesa-Ercegovac; Marija Matic; Nebojsa Ninkovic; Branislava Ivanovic; Tatjana Simic

Abstract Background: We aimed to study the relationship between markers of oxidative lipid or protein damage and ventricular remodeling and the validity of 8-epi-prostaglandin F2α (8-epi-PGF2α) as an indicator of disease severity in patients with ischemic chronic heart failure (CHF). Patients and methods: We enrolled four groups of 12 patients with varying CHF according to the New York Heart Association (NYHA) classification and 25 controls. Urinary 8-epi-PGF2α and plasma malondialdehyde and protein thiol (P-SH) groups were correlated with echocardiographic indices of remodeling. The reliability of isoprostanes was analyzed by a receiver operating characteristics (ROC) curve. Results: NYHA class III and IV patients exhibited elevated 8-epi-PGF2α levels, increased malondialdehyde concentrations and decreased P-SH groups when compared to controls and NYHA I and II patients. 8-Epi-PGF2α and P-SH groups correlated significantly with indices of remodeling. The ROC curve drawn for 8-epi-PGF2α allowed us to differentiate NYHA class III and IV patients from NYHA class I and II patients with a sensitivity of 95.8% and specificity of 95.8% (cut off 0.84 ng/mg creatinine; area under curve 0.99; P < 0.001). Conclusions: Markers of oxidative damage are unlikely to play a significant role in early stages of CHF. However, they might become important in the course of CHF when their concentrations reach critical levels. Urinary 8-epi-PGF2α is a reliable indicator of symptomatic CHF.


Urologia Internationalis | 2009

Comparison of Open Nephroureterectomy and Open Conservative Management of Upper Urinary Tract Transitional Cell Carcinoma

Dejan Dragicevic; Milan Djokic; Tatjana Pekmezovic; Aleksandar Vuksanovic; Sava Micic; J. Hadzi-Djokic; Cane Tulic; Dragica Milenkovic; Marija Pljesa-Ercegovac; Tatjana Simic

Introduction: The treatment preserving the kidney for upper urinary tract (UUT) transitional cell carcinoma (TCC) is still controversial. We aimed to elucidate the results of open conservative surgery and compare them with the results of radical nephroureterectomy (RNU). Patients and Methods: The study included 107 patients with UUT TCC treated by open conservative surgery (21 patients) or nephroureterectomy (86 patients). Epidemiological, clinical and pathological characteristics of patients as well as 5-year survival rates were compared between groups. Results: Patients treated by conservative surgery had a significantly higher rate of bilateral tumors (38% vs. 3%, p = 0.0001) and smaller tumor size than those treated by radical operations (2.60 ± 1.24 vs. 3.99 ± 3.94 cm, p = 0.060). Five-year survival rates for patients treated by conservative and radical surgery were 59 and 55%, respectively. Within the group of patients treated by conservative surgery, 5-year overall survival rates of patients operated due to imperative and elective indications were 41 and 75%, respectively. In univariate analysis, RNU was a statistically significant predictor of poorer outcome of the disease in comparison with conservative surgery (HR = 2.2, 95% CI 1.1–4.6, p = 0.030). Conclusions: The mode of operation affects the outcome of UUT TCC patients, in addition to factors such as tumor grade, stage and size.


Journal of Clinical Laboratory Analysis | 2013

The Role of Serum VCAM‐1 and TNF‐α as Predictors of Mortality and Morbidity in Patients with Chronic Heart Failure

Ana Savic-Radojevic; Slavica Radovanovic; Tatjana Pekmezovic; Marija Pljesa-Ercegovac; Dragan Simic; Tatjana Djukic; Marija Matic; Tatjana Simic

To assess the prognostic significance of four inflammatory markers (TNF‐α, high sensitive C‐reactive protein (hs‐CRP), intercellular cell adhesion molecule‐1 (ICAM‐1), vascular cell adhesion molecule‐1 (VCAM‐1)) in chronic heart failure (CHF) patients with respect to individual outcomes, especially disease exacerbation and mortality.


Hormones (Greece) | 2014

Effect of hyperglycemia and hyperinsulinemia on glutathione peroxidase activity in non-obese women with polycystic ovary syndrome

Ana Savic-Radojevic; Ivana Bozic Antic; Vesna Coric; Jelica Bjekic-Macut; Tanja Radic; Milos Zarkovic; Tatjana Djukic; Marija Pljesa-Ercegovac; Dimitrios Panidis; Ilias Katsikis; Tatjana Simic; Djuro Macut

OBJECTIVE: In order to gain deeper insight into molecular mechanisms underlying oxidative stress (OS) and its relation to insulin resistance and hyperandrogenemia, plasma markers of OS and antioxidant glutathione-peroxidase (GPX) activity were studied in non-obese polycystic ovary syndrome (PCOS) women via the oral glucose tolerance test (OGTT) and hyperinsulinemic euglycemic clamp. DESIGN: In 36 PCOS women, plasma nitrotyrosine, thiol groups, uric acid (UA) and GPX activity were studied during OGTT and clamp. Insulin resistance was assessed by the homeostasis model (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), Matsuda insulin sensitivity index (ISI) and M/I ratio. RESULTS: In PCOS patients, significant positive correlations were obtained for UA with testosterone (r=0.385, p=0.039) as well as indices of insulin resistance. Acute hyperglycemia during OGTT induced alteration in both OS markers and GPX. The change in nitrotyrosine and GPX during OGTT correlated with testosterone (r=0.543, p=0.036 and r=−0.457, p=0.025, respectively). The most significant association was found between OS markers and ISI. CONCLUSIONS: Our results indicate that non-obese PCOS women are prone to oxidative stress induced by hyperglycemia, but this seems not to be related to the direct effect of hyperinsulinemia during clamp. Oxidative stress markers correlated with indices of insulin resistance and circulating testosterone.

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Vesna Coric

University of Belgrade

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Tanja Radic

University of Belgrade

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