Polona Žigon

Dr. Polona Žigon

Department of rheumatolgy, University Medical Center Ljubljana, Ljubljana, Slovenia
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Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 May 2019 in Frontiers in Cardiovascular Medicine
Verified
Journal Article
Open access
BBBlaž Burja
Blaž Burja
TKTadeja Kuret
Tadeja Kuret
TJTea Janko
Tea Janko
DTDijana Topalovic
Dijana Topalovic
LŽLada Živković
Lada Živković
MFMojca Frank-Bertoncelj
Mojca Frank-Bertoncelj
Olive leaf extract (OLE) is used in traditional medicine as a food supplement and as an over-the-counter drug for a variety of its effects, including anti-inflammatory and anti-atherosclerotic ones. Mechanisms through which OLE could modulate these pathways in human vasculature remain largely unknown. Serum amyloid A (SAA) plays a causal role in atherosclerosis and cardiovascular diseases and induces pro-inflammatory and pro-adhesive responses in human coronary artery endothelial cells (HCAEC). Within this study we explored whether OLE can attenuate SAA-driven responses in HCAEC. HCAEC were treated with SAA (1,000 nM) and/or OLE (0.5 and 1 mg/ml). The expression of adhesion molecules VCAM-1 and E-selectin, matrix metalloproteinases (MMP2 and MMP9) and microRNA 146a, let-7e, and let-7g (involved in the regulation of inflammation) was determined by qPCR. The amount of secreted IL-6, IL-8, MIF, and GRO-α in cell culture supernatants was quantified by ELISA. Phosphorylation of NF-κB was assessed by Western blot and DNA damage was measured using the COMET assay. OLE decreased significantly released protein levels of IL-6 and IL-8, as well as mRNA expression of E-selectin in SAA-stimulated HCAEC and reduced MMP2 levels in unstimulated cells. Phosphorylation of NF-κB (p65) was upregulated in the presence of SAA, with OLE significantly attenuating this SAA-induced effect. OLE stabilized SAA-induced upregulation of microRNA-146a and let-7e in HCAEC, suggesting that OLE could fine-tune the SAA-driven activity of NF-κB by changing the microRNA networks in HCAEC. SAA induced DNA damage and worsened the oxidative DNA damage in HCAEC, whereas OLE protected HCAEC from SAA- and H2O2-driven DNA damage. OLE significantly attenuated certain pro-inflammatory and pro-adhesive responses and decreased DNA damage in HCAEC upon stimulation with SAA. The reversal of SAA-driven endothelial activation by OLE might contribute to its anti-inflammatory and anti-atherogenic effects in HCAEC.

1 January 2015 in Journal of Immunology Research
Verified
Journal Article
Open access
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Polona ŽigonPolona Žigon
Polona Žigon
KPKatja Perdan Pirkmajer
Katja Perdan Pirkmajer
MTMatija Tomšič
Matija Tomšič
TKTanja Kveder
Tanja Kveder
BBBorut Božič
Borut Božič
AAAleš Ambrožič
Aleš Ambrožič
Objective. To determine the prevalence and clinical association of anti-phosphatidylserine/prothrombin antibodies (aPS/PT) in patients with a history of pregnancy complications relevant to antiphospholipid syndrome (APS).Materials and Methods. Two hundred and eleven patients with a history of (a) three or more consecutive miscarriages before 10th week of gestation (WG) (n=64), (b) death of a morphologically normal fetus beyond 10th WG (n=72), (c) premature birth of a morphologically normal neonate before 34th WG due to eclampsia, preeclamsia and placental insufficiency (n=33), and (d) less than three unexplained consecutive miscarriages before 10th WG (n=42). Subjects sera were analyzed for lupus anticoagulant (LA), anti-cardiolipin (aCL), anti-β2-glycoprotein I (anti-β2GPI), and aPS/PT antibodies.Results. 41/169 (24.3%) of patients were positive for at least one measured aPL. The highest prevalence was found for aPS/PT and aCL (13.0% and 12.4%, resp.) followed by LA (7.7%) and anti-β2GPI (7.1%). 11/169 with APS-related obstetric manifestations had only aPS/PT. 17.8% of patients were positive for LA or aCL and/or anti-β2GPI; however when adding the aPS/PT results, an additional 7% of patients could be evaluated for APS.Conclusion. aPS/PT are associated with recurrent early or late abortions and with premature delivery irrespective of other aPL.

24 August 2018 in Clinical Rheumatology
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Journal Article
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BBBlaž Burja
Blaž Burja
JFJulia Feichtinger
Julia Feichtinger
KLKatja Lakota
Katja Lakota
GTGerhard G. Thallinger
Gerhard G. Thallinger
SSSnežna Sodin-Šemrl
Snežna Sodin-Šemrl
AHAlojzija Hocevar
Alojzija Hocevar
Early diagnosis and treatment of giant cell arteritis (GCA) is crucial for preventing ischemic complications. Multiple serological markers have been identified; however, there is a distinct lack of predicting markers for GCA relapse and complications. Our main objective was to identify serological parameters in a large cohort of treatment-naïve GCA patients, which could support clinicians in evaluating the course of the disease. Clinical data was gathered, along with analyte detection using Luminex technology, ELISA, and nephelometry, among others. Unsupervised hierarchical clustering and principal component analysis of analyte profiles were performed to determine delineation of GCA patients and healthy blood donors (HBDs). Highest, significantly elevated analytes in GCA patients were SAA (83-fold > HBDs median values), IL-23 (58-fold), and IL-6 (11-fold). Importantly, we show for the first time significantly changed levels of MARCO, alpha-fetoprotein, protein C, resistin, TNC, TNF RI, M-CSF, IL-18, and IL-31 in GCA versus HBDs. Changes in levels of SAA, CRP, haptoglobin, ESR, MMP-1 and MMP-2, and TNF-alpha were found associated with relapse and visual disturbances. aCL IgG was associated with limb artery involvement, even following adjustment for multiple testing. Principal component analysis revealed clear delineation between HBDs and GCA patients. Our study reveals biomarker clusters in a large cohort of patients with GCA and emphasizes the importance of using groups of serological biomarkers, such as acute phase proteins, MMPs, and cytokines (e.g. TNF-alpha) that could provide crucial insight into GCA complications and progression, leading to a more personalized disease management.

11 August 2018 in Clinical Rheumatology
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Journal Article
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Polona ŽigonPolona Žigon
Polona Žigon
APAnuška Podovšovnik
Anuška Podovšovnik
AAAleš Ambrožič
Aleš Ambrožič
MTMatija Tomšič
Matija Tomšič
AHAlojzija Hočevar
Alojzija Hočevar
SČSaša Čučnik
Saša Čučnik

1 January 2013 in Journal of Immunology Research
Verified
Journal Article
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Polona ŽigonPolona Žigon
Polona Žigon
SČSaša Čučnik
Saša Čučnik
AAAleš Ambrožič
Aleš Ambrožič
TKTanja Kveder
Tanja Kveder
SŠSnežna Sodin Šemrl
Snežna Sodin Šemrl
BBBorut Božič
Borut Božič
Antiprothrombin antibodies, measured with phosphatidylserine/prothrombin complex (aPS/PT) ELISA, have been reported to be associated with antiphospholipid syndrome (APS). They are currently being evaluated as a potential classification criterion for this autoimmune disease, characterized by thromboses and obstetric complications. Given the present lack of clinically useful tests for the accurate diagnosis of APS, we aimed to evaluatein-houseand commercial assays for determination of aPS/PT as a potential serological marker for APS. We screened 156 patients with systemic autoimmune diseases for antibodies against PS/PT,β2-glycoprotein I, cardiolipin and for lupus anticoagulant activity. We demonstrated a high degree of concordance between the concentrations of aPS/PT measured with thein-houseand commercial assays. Both assays performed comparably relating to the clinical manifestations of APS, such as arterial and venous thromboses and obstetric complications. IgG aPS/PT represented the strongest independent risk factor for the presence of obstetric complications, among all tested aPL. Both IgG and IgM aPS/PT were associated with venous thrombosis, but not with arterial thrombosis. Most importantly, the association between the presence of IgG/IgM aPS/PT and lupus anticoagulant activity was highly significant. Taken together, aPS/PT antibodies detected with thein-houseor commercial ELISA represent a promising serological marker for APS and its subsets.

13 May 2020 in Cells
Verified
Journal Article
Open access
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USUla Stok
Ula Stok
EBElizabeta Blokar
Elizabeta Blokar
MLMetka Lenassi
Metka Lenassi
MHMarija Holcar
Marija Holcar
MFMojca Frank-Bertoncelj
Mojca Frank-Bertoncelj
Polona ŽigonPolona Žigon
Polona Žigon
Antiphospholipid syndrome (APS) is a systemic autoimmune disease, characterized by thrombosis, obstetric complications and the presence of antiphospholipid antibodies (aPL), which drive endothelial injury and thrombophilia. Extracellular vesicles (EVs) have been implicated in endothelial and thrombotic pathologies. Here, we characterized the quantity, cellular origin and the surface expression of biologically active molecules in small EVs (sEVs) isolated from the plasma of thrombotic APS patients (n = 14), aPL-negative patients with idiopathic thrombosis (aPL-neg IT, n = 5) and healthy blood donors (HBD, n = 7). Nanoparticle tracking analysis showed similar sEV sizes (110–170 nm) between the groups, with an increased quantity of sEVs in patients with APS and aPL-neg IT compared to HBD. MACSPlex analysis of 37 different sEV surface markers showed endothelial (CD31), platelet (CD41b and CD42a), leukocyte (CD45), CD8 lymphocyte and APC (HLA-ABC) cell-derived sEVs. Except for CD8, these molecules were comparably expressed in all study groups. sEVs from APS patients were specifically enriched in surface expression of CD62P, suggesting endothelial and platelet activation in APS. Additionally, APS patients exhibited increased CD133/1 expression compared to aPL-neg IT, suggesting endothelial damage in APS patients. These findings demonstrate enhanced shedding, and distinct biological properties of sEVs in thrombotic APS.