Kamelija Zarkovic

University of Split-School of Medicine, Spalato, Splitsko-Dalmatinska, Croatia

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Publications (87)192.44 Total impact


  • No preview · Article · Oct 2015
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    ABSTRACT: Aims: The aim of the present study was to immunohistochemically investigate the expression and prognostic significance of putative cancer stem cell markers CD117 (c-kit), CD34, CD20 and CD15 in a cohort of patients with primary choroidal and ciliary body melanoma. Methods: The immunohistochemical expression of these markers was evaluated using DAB and AEC chromogens on paraffin-embedded tissue samples from 40 patients who underwent enucleation in the period from 1985 through 2000. Thirty-one patients had adequate tissue specimens for analysis. Results: CD117 overexpression was observed in 12 of the 31 samples (39%) when AEC chromogen was used and in 14 of 26 (54%) samples when DAB was used. CD15 positivity was seen in 3 out of 30 (10%) samples with AEC and in 6 out of 26 (23%) samples with DAB. CD20 and CD34 exhibited no positivity in the tested samples. During an average follow-up time of 8.7 years (range, 0.5-22 years), 17 patients (55%) died due to metastatic disease. The Kaplan-Meier plots showed a significantly shorter overall and disease-free survival in CD117-positive patients when the AEC chromogen was used. CD15 expression was not associated with patients’ survival. In multivariate analysis, patients expressing the CD117 AEC had 4.13 times higher risk of lethal outcome in comparison with CD117 AEC negative patients. Conclusions: Our retrospective cohort study has for the first time demonstrated a small proportion of CD15-positive uveal melanomas. CD117 AEC overexpression was associated with a worse outcome in patients with choroidal and ciliary body melanoma. Further studies should confirm the validity of these observations and their potential for targeted treatment modalities.
    Full-text · Article · Aug 2015 · Journal of Clinical Pathology
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    ABSTRACT: Otosclerosis is a complex disease of the human otic capsule with highest incidence in adult Caucasians. So far, many possible etiological factors like genetics, HLA, autoimmunity, viruses, inflammation, and hormones have been investigated but still the development of the disease remains unclear. Currently, the surgical replacement of stapes (stapedotomy) remains the best possible treatment option. In this review, we analyze different etiological factors studied so far in otosclerosis pathophysiology and discuss most recent findings and possible new research pathways. Copyright © 2015 Elsevier B.V. All rights reserved.
    Full-text · Article · Aug 2015 · Hearing Research
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    ABSTRACT: Chronic exposure to ultraviolet (UV) radiations causes oxidative stress, which is involved in photoaging and actinic elastosis. UV and reactive oxygen species generate lipid peroxidation products, including the α,β-unsaturated carbonyl compounds such as acrolein or 4-hydroxynonenal (4-HNE). These aldehydes can modify proteins of the extracellular matrix, but their role in the pathogenesis of photoaging is not clarified. The aim of this study was to investigate whether these aldehydes contribute to alter elastin metabolism and whether topical carbonyl scavengers delay UV-induced skin photoaging. Hairless mice (4-6 weeks old) daily exposed to UV-A (20 Joules/cm(2)/day, up to 600 Joules/cm(2)) exhibited the typical features of photoaging, associated with a significant increase in 4-HNE- and acrolein-adduct content and elastotic material deposition. Immunofluorescence studies showed the accumulation of 4-HNE-adducts on elastin in the dermis of UV-A-exposed mice. This was mimicked in vitro by incubating orcein-elastin with 4-HNE or acrolein, which altered its digestion by leukocyte-elastase, a feature possibly involved in the accumulation of elastotic material. A daily topical application of carnosine completely reversed the development of photoaging alterations, and 4-HNE-adduct formation on elastin. These data emphasize the role of 4-HNE and acrolein in the mechanism of photoaging, and the preventive effect of carbonyl scavengers.Journal of Investigative Dermatology accepted article preview online, 04 March 2015. doi:10.1038/jid.2015.84.
    Full-text · Article · Mar 2015 · Journal of Investigative Dermatology
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    ABSTRACT: Vascular endothelial cell (VEC) senescence is considered an early event in the development of atherosclerotic lesions. Stressful stimuli, in particular oxidative stress, have been linked to premature senescence in the vasculature. Foam cells are a major source of reactive oxygen species and may play a role in the induction of VEC senescence; hence, we investigated their involvement in the induction of VEC senescence in a co-culture transwell system. Primary bovine aortic endothelial cells, exposed to the secretome of THP-1 monocyte-derived foam cells, were analysed for the induction of senescence. Senescence associated b-galactosidase activity and the expression of p16 and p21 were increased, whereas phosphorylated retinoblastoma protein was reduced. This senescent phenotype was mediated by 4-hydroxnonenal (4-HNE), a lipid per-oxidation product secreted from foam cells; scavenging of 4-HNE in the co-culture medium blunted this effect. Furthermore, both foam cells and 4-HNE increased the expression of the pro-oxidant thioredoxin-interacting protein (TXNIP). Molecular manipulation of TXNIP expression confirmed its involvement in foam cell-induced senescence. Previous studies showed that peroxisome proliferator-activated receptor (PPAR)d was activated by 4-hydroalkenals, such as 4-HNE. Pharmacological interventions supported the involvement of the 4-HNE-PPARd axis in the induction of TXNIP and VEC senescence. The association of TXNIP with VEC senescence was further supported by immunofluorescent staining of human carotid plaques in which the expression of both TXNIP and p21 was augmented in endothelial cells. Collectively, these findings suggest that foam cell-released 4-HNE activates PPARd in VEC, leading to increased TXNIP expression and consequently to senescence. Keywords: atherosclerosis senescence foam cells VEC 4-HNE PPARd TXNIP
    Full-text · Article · Jan 2015 · Journal of Cellular and Molecular Medicine
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    ABSTRACT: Vascular aging is associated with structural and functional modifications of the arteries, and by an increase in arterial wall thickening in the intima and the media, mainly resulting from structural modifications of the extracellular matrix (ECM) components. Among the factors known to accumulate with aging, advanced lipid peroxidation end products (ALEs) are a hallmark of oxidative stress-associated diseases such as atherosclerosis. Aldehydes generated from the peroxidation of polyunsaturated fatty acids (PUFA), (4-hydroxynonenal, malondialdehyde, acrolein), form adducts on cellular proteins, leading to a progressive protein dysfunction with consequences in the pathophysiology of vascular aging. The contribution of these aldehydes to ECM modification is not known. This study was carried out to investigate whether aldehyde-adducts are detected in the intima and media in human aorta, whether their level is increased in vascular aging, and whether elastin fibers are a target of aldehyde-adduct formation. Immunohistological and confocal immunofluorescence studies indicate that 4-HNE-histidine-adducts accumulate in an age-related manner in the intima, media and adventitia layers of human aortas, and are mainly expressed in smooth muscle cells. In contrast, even if the structure of elastin fiber is strongly altered in the aged vessels, our results show that elastin is not or very poorly modified by 4-HNE. These data indicate a complex role for lipid peroxidation and in particular for 4-HNE in elastin homeostasis, in the vascular wall remodeling during aging and atherosclerosis development.
    Full-text · Article · Dec 2014
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    ABSTRACT: In Ethiopians, like in other Africans, the incidence of otosclerosis is lower than in Western and Asian populations. Unfortunately, due to the lack of available otorhinolaryngology specialists many patients are not treated and suffer the progression of the disease and severe hearing loss. This program of the Global ENT Outreach Organization (GEO) together with the Ethiopian partners was done to help some of these patients and in parallel to evaluate the presence of the oxidative stress bioactive marker 4-hydroxynonenal (HNE), which is known as major lipid peroxidation product and the second messenger of free radicals, in the otosclerotic bone specimens. Namely, we described recently that as HNE acts as a bone growth regulator associated with pathogenesis of otosclerosis. The prospective study conducted at the ENT Department of the Migbare Senay General Hospital, Addis Ababa, Ethiopia in June 2012, under the auspices of the Global ENT Outreach Organization, USA. Altogether 36 patients (male = 12, female = 24) underwent surgery due to the previous otosclerosis diagnosis based on the clinical and audiometric findings. The bone samples were harvested from patients with intraoperatively confirmed otosclerosis diagnosis. Immunohistochemistry for HNE-modified proteins was carried out on formalin-fixed paraffin-embedded specimens. The presence of HNE was found in almost all bone samples analyzed, without particular difference in the HNE distribution pattern between the otosclerotic and respective control bone specimens. Although there was no significant association between the HNE appearance and otosclerotic bone outgrowth observed, several cases have shown tendency of higher HNE expression in patients with more severe hearing loss. The results of the present study are in contrast with our previous findings obtained on European patients most likely due to the differences between studied population groups.
    Full-text · Article · Sep 2014 · Archiv für Klinische und Experimentelle Ohren- Nasen- und Kehlkopfheilkunde
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    ABSTRACT: Abstract The prevalence of metabolic syndrome components including obesity, dyslipidemia, insulin resistance and hepatic steatosis is rapidly increasing in wealthy societies. It is accepted that inflammation/oxidative stress are involved in the initiation/evolution of the metabolic syndrome features. The present work was designed to evaluate the effects of three major cellular ROS production systems on obesity, glucose tolerance and hepatic steatosis development and on oxidative stress onset. To do so, forty young male Sprague Dawley rats were divided into 5 groups: 1-control group, 2-high fat (HF) group (60% energy from fat), 3-HF+MitoQ (mitochondrial ROS scavenger), 4-HF+Apocynin (NADPH oxidase inhibitor), 5-HF+Allopurinol (xanthine oxidase inhibitor). After 8 weeks of these treatments, surrogate metabolic syndrome, mitochondrial function and oxidative stress markers were measured in blood and liver. As expected, rats fed the high fat diet exhibited increased body weight, glucose intolerance, overt hepatic steatosis and increased hepatic oxidative stress. The impacts of the studied ROS inhibitors on these aspects of the metabolic syndrome were markedly different. MitoQ showed the most clinically relevant effects, attenuating body weight gain and glucose intolerance provoked by the HF diet. Both Apocynin and Allopurinol showed limited effects suggesting secondary roles of xanthine oxidase or NADPH oxidase-dependent ROS production in the onset of oxidative stress-dependent obesity, glucose intolerance and hepatic steatosis process. Thus, MitoQ revealed the central role of mitochondrial oxidative stress in the development of metabolic syndrome and suggested that mitochondria-targeted antioxidants may be worth considering as potentially helpful therapies for metabolic syndrome features.
    Full-text · Article · Jul 2014 · Free Radical Research
  • Helena Sarac · Srdjana Telarovic · Kamelija Zarkovic

    No preview · Article · Jul 2014 · Acta neurologica Belgica

  • No preview · Article · Jun 2014
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    ABSTRACT: Elastin is a long-life protein and a key-component of connective tissues. The tissular elastin content decreases during chronological aging, and the mechanisms underlying its slow repair are not known. Lipid oxidation products that accumulate in aged tissues may generate protein dysfunction. We hypothesized that 4-hydroxynonenal (4-HNE), a highly reactive α,β-aldehydic product generated from polyunsaturated fatty acid peroxidation, could contribute to inhibit elastin repair by antagonizing the elastogenic signalling of Transforming Growth Factor-β1 (TGF-β1) in skin fibroblasts. We report that low 4-HNE concentration (2µmol/L), inhibits the upregulation of tropoelastin expression stimulated by TGF-β1, in human and murine fibroblasts. The study of signaling pathways potentially involved in the regulation of elastin expression, showed that 4-HNE did not block the phosphorylation of Smad3, an early step of TGF-β1 signaling, but inhibited the nuclear translocation of Smad2. Concomitantly, 4-HNE modified and stimulated the phosphorylation of the Epidermal Growth Factor receptor (EGFR) and subsequently ERK1/2 activation, leading to the phosphorylation/stabilization of the Smad transcriptional corepressor TGIF, which antagonizes TGF-β1 signaling. Inhibitors of EGFR (AG1478), Mek/ERK (PD98059), EGFR-specific siRNAs, reversed the inhibitory effect of 4-HNE on TGF-β1-induced nuclear translocation of Smad2 and tropoelastin synthesis. In vivo studies on aortas from aged C57BL/6 mice, showed that EGFR is modified by 4-HNE, in correlation with an increased 4-HNE-adduct accumulation and decreased elastin content. Altogether, these data suggest that 4-HNE inhibits the elastogenic activity of TGF-β1, by modifying and activating the EGFR/ERK/TGIF pathway, which may contribute to alter elastin repair in chronological aging and oxidative stress-associated aging processes.
    No preview · Article · Feb 2014 · Free Radical Biology and Medicine
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    Full-text · Article · Sep 2013 · Free Radical Biology and Medicine
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    ABSTRACT: Despite huge advances in medicine, glioblastoma multiforme (GBM) remains a highly lethal, fast-growing tumour that cannot be cured by currently available therapies. However, extracranial and extraneural dissemination of GBM is extremely rare, but is being recognised in different imaging studies. To date, the cause of the GBM metastatic spread still remains under discussion. It probably develops at the time of intracranial progression following a surgical procedure. According to other hypothesis, the metastases are a consequence of spontaneous tumour transdural extension or haematogenous dissemination. We present a case of a 59-year-old woman with symptomatic leptomeningeal and intramedullary metastases of GBM who has been previously surgically treated with primary subtotal resection and underwent a repeated surgery during adjuvant radiotherapy and chemotherapy with temozolomide. Today, the main goal of surgery and chemoradiotherapy is to prevent neurologic deterioration and improve health-related quality of life. With this paper, we want to present this rare entity and emphasise the importance of a multidisciplinary approach, a key function in the management of brain tumour patients. The prognosis is still very poor although prolongation of survival can be obtained. Finally, although rare, our case strongly suggests that clinicians should be familiar with the possibility of the extracranial spread of GBM because as treatment improvements provide better control of the primary tumour and improving survival, metastatic disease will be increasingly encountered.
    Full-text · Article · Mar 2013 · World Journal of Surgical Oncology
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    Neven Zarkovic · Ana Cipak · Morana Jaganjac · Suzana Borovic · Kamelija Zarkovic
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    ABSTRACT: There is growing body of evidence that oxidative stress, i.e. excess in production of reactive oxygen species, can lead to covalent modification of proteins with bioactive aldehydes that are mostly produced under lipid peroxidation of polyunsaturated fatty acids. Thus generated reactive aldehydes are considered as second messengers of free radicals because they react with major bioactive macromolecules, in particular with various humoral and cellular proteins changing their structure and functions. Therefore, the aldehydic-protein adducts, in particular those involving 4-hydroxy-2-nonenal, malondialdehyde and acrolein can be valuable biomarkers of numerous pathophysiological processes. The development of immunochemical methods is increasing the possibilities to study such non-enzymatic protein modifications, on the one hand, while on the other hand the increase of knowledge on bioactivities of the aldehydes and their protein adducts might lead to better prevention, diagnosis and treatments of pathophysiological processes associated with lipid peroxidation and oxidative stress in general. This article is part of a Special Issue entitled: Protein Modifications.
    Full-text · Article · Feb 2013 · Journal of proteomics
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    ABSTRACT: Otosclerosis is a complex disease characterized by an abnormal bone turnover of the otic capsule resulting in conductive hearing loss. Recent findings have shown that Angiotensin II (Ang II), a major effector peptide of the renin-angiotensin system, plays important role in pathophysiology of otosclerosis, most likely by its pro-inflammatory effects on the bone cells. Since reactive oxygen species play a role both in inflammation and in cellular signalling pathway of Ang II, the appearance of the "second messenger of free radicals" the aldehyde 4-hydroxynonenal (HNE) protein adducts in otosclerotic bone has been analysed. Immunohistochemical analysis of HNE-modified proteins on tissue samples of the stapedial bones performed on 15 otosclerotic patients and 6 controls, revealed regular HNE-protein adducts presence in the subperiosteal parts of control bone specimens, while irregular areas of the pronounced HNE-protein adducts presence were found within stapedial bone in case of otosclerosis. To study possible interference of HNE and Ang II in human bone cell proliferation, differentiation and induction of apoptosis we used an in vitro model of osteoblast-like cells. HNE interacted with Ang II in a dose-dependent manner, both by forming HNE-Ang II adducts, as revealed by immunoblotting, and by modification of effects on cultured cells. Namely, treatment with 0.1nM Ang II and 2.5μM HNE stimulated proliferation, while treatment with 10μM HNE or in combination with Ang II (0.1, 0.5 and 1nM) decreased cell proliferation. Moreover, 10μM HNE alone and with Ang II (except if 1nM Ang II was used) increased cellular differentiation and apoptosis. HNE 5μM did not affect differentiation or significantly changed apoptosis. On the other hand, when cells were treated with lower concentrations of HNE and Ang II we have observed decrease in cellular differentiation (combination of 1.0 or 2.5μM HNE with 0.1nM Ang II) and decrease in apoptosis (0.1 and 0.5nM Ang II). Cellular necrosis was increased with 5 and 10μM HNE if given alone or combined with Ang II, while 0.5nM Ang II and combination of 1μM HNE with Ang II (0.1 and 0.5nM) reduced necrosis. These results indicate that HNE and Ang II might act mutually dependent in regulation of the bone cell growth and in pathophysiology of otosclerosis.
    Full-text · Article · Dec 2012 · Free Radical Biology and Medicine
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    ABSTRACT: The involvement of granulocytes in immune response against cancer is not well understood. Depending on the cytokine milieu in which they act and on their oxidative burst, granulocytes may play either an inhibitory or stimulatory role in tumour growth. Unsaturated fatty acids, essential components of cellular membranes and storage lipids, are susceptible to granulocyte-derived reactive oxygen species (ROS). ROS can induce lipid peroxidation (LPO) resulting in the destruction of biomembranes. Thus, murine W256 tumour progressing and tumour regressing animal models were used to study the involvement of plasma inflammatory mediators and oxidative burst of circulating granulocytes in malignant destruction and detrimental tumour growth. The involvement of LPO-derived aldehydes (i.e. acrolein, 4-hydroxy-2-nonenal and malondialdehyde) and myeloperoxidase (MPO) appearance in the granulocyte anti-cancer response were further evaluated. The results obtained revealed a significant increase in neutrophil elastase in animals with regressing tumour. Furthermore, the presence of MPO in tumour microenvironment was accompanied by the formation of acrolein only 5 h after tumour transplantation and its presence increased during tumour regression. Later, at an early stage of tumour regression, the presence of other LPO-derived aldehydes were also observed. The results obtained suggest that elevated neutrophil elastase and initiation of LPO may play an important role in the tumour development leading to tumour regression.
    Full-text · Article · Nov 2012 · Clinical & Experimental Immunology
  • Gordan Grahovac · Darko Chudy · Zdravko Heinrich · Kamelija Zarkovic

    No preview · Article · Oct 2012 · Clinical neurology and neurosurgery

  • No preview · Article · Sep 2012
  • Mario Habek · Ivan Adamec · Kamelija Zarkovic · David Ozretic · Vesna V Brinar

    No preview · Article · Sep 2012 · The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques
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    ABSTRACT: PET/CT is starting to play an important role in evaluating fever of unknown origin (FUO), due to its ability to localize and delineate areas of high metabolic activity, such as neoplastic proliferation and inflammation, including vasculitis. We present a case of giant cell arteritis (GCA) in a 72-year-old female patient admitted to our department with a 4-month history of FUO, weight loss and fatigue, without specific symptoms or signs. Laboratory investigations suggested acute phase response, with a pronounced erythrocyte sedimentation rate, high CRP level and microcytic anemia. A thorough diagnostic evaluation was performed to exclude an unknown primary tumor, which was initially suspected due to a positive family history of cancer. Surprisingly, PET/CT revealed large vessel vasculitis affecting the ascending, descending and abdominal aorta, as well as subclavian, proximal brachial and carotid arteries bilaterally. Biopsy of the superficial temporal artery confirmed the diagnosis of GCA. Treatment with methylprednisolone and azathioprine led to resolution of clinical symptoms and normalization of laboratory parameters. In addition to the use of PET/CT in the evaluation of FUO, its value as a method complementary to temporal artery biopsy is also discussed.
    No preview · Article · Mar 2012 · Rheumatology International

Publication Stats

1k Citations
192.44 Total Impact Points

Institutions

  • 2014-2015
    • University of Split-School of Medicine
      Spalato, Splitsko-Dalmatinska, Croatia
  • 2009-2015
    • Klinički Bolnički Centar Split
      Spalato, Splitsko-Dalmatinska, Croatia
  • 1991-2015
    • University of Zagreb
      • • Department of Pathology
      • • Department of Pharmacology
      • • Department of Gynecology and Obstetrics
      • • Department of Radiology
      Zagrabia, Grad Zagreb, Croatia
  • 2007-2010
    • University Hospital Centre Zagreb
      • Division of Neuropathology
      Zagrabia, Grad Zagreb, Croatia
  • 2001
    • Karl-Franzens-Universität Graz
      Gratz, Styria, Austria
    • Ruđer Bošković Institute
      • Division of Molecular Medicine
      Zagrabia, Grad Zagreb, Croatia
  • 1998
    • KBC Osijek
      Osik, Osječko-Baranjska, Croatia