Alen Vrtarić

Dr. Alen Vrtarić


Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

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

Representative Publications

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25 April 2021 in Cancers
Verified
Journal Article
Open access
PDF file
IAIrena Abramovic
Irena Abramovic
BVBorna Vrhovec
Borna Vrhovec
LALucija Škara Abramović
Lucija Škara Abramović
AVAlen Vrtarić
Alen Vrtarić
NGNora Nikolac Gabaj
Nora Nikolac Gabaj
NSNino Sincic
Nino Sincic
Prostate cancer (PCa) is the most commonly diagnosed neoplasm among men. Since it often resembles benign prostate hyperplasia (BPH), biomarkers with a higher differential value than PSA are required. Epigenetic biomarkers in liquid biopsies, especially miRNA, could address this challenge. The absolute expression of miR-375-3p, miR-182-5p, miR-21-5p, and miR-148a-3p were quantified in blood plasma and seminal plasma of 65 PCa and 58 BPH patients by digital droplet PCR. The sensitivity and specificity of these microRNAs were determined using ROC curve analysis. The higher expression of miR-182-5p and miR-375-3p in the blood plasma of PCa patients was statistically significant as compared to BPH (p = 0.0363 and 0.0226, respectively). Their combination achieved a specificity of 90.2% for predicting positive or negative biopsy results, while PSA cut-off of 4 µg/L performed with only 1.7% specificity. In seminal plasma, miR-375-3p, miR-182-5p, and miR-21-5p showed a statistically significantly higher expression in PCa patients with PSA >10 µg/L compared to ones with PSA ≤10 µg/L. MiR-182-5p and miR-375-3p in blood plasma show higher performance than PSA in discriminating PCa from BPH. Seminal plasma requires further investigation as it represents an obvious source for PCa biomarker identification.

Verified
Journal Article
Open access
PDF file
IBIva Bešlić
Iva Bešlić
Liborija Lugović-MihićLiborija Lugović-Mihić
Liborija Lugović-Mihić
AVAlen Vrtarić
Alen Vrtarić
ABAnte Bešlić
Ante Bešlić
ISIvana Skrinjar
Ivana Skrinjar
MAMarinko Artuković
Marinko Artuković
Melatonin is the main hormone that regulates the sleep cycle, and it is mostly produced by the pineal gland from the amino acid tryptophan. It has cytoprotective, immunomodulatory, and anti-apoptotic effects. Melatonin is also one of the most powerful natural antioxidants, directly acting on free radicals and the intracellular antioxidant enzyme system. Furthermore, it participates in antitumor activity, hypopigmentation processes in hyperpigmentary disorders, anti-inflammatory, and immunomodulating activity in inflammatory dermatoses, maintaining the integrity of the epidermal barrier and thermoregulation of the body. Due predominantly to its positive influence on sleep, melatonin can be used in the treatment of sleep disturbances for those with chronic allergic diseases accompanied by intensive itching (such as atopic dermatitis and chronic spontaneous urticaria). According to the literature data, there are also many proven uses for melatonin in photoprotection and skin aging (due to melatonin’s antioxidant effects and role in preventing damage due to DNA repair mechanisms), hyperpigmentary disorders (e.g., melasma) and scalp diseases (such as androgenic alopecia and telogen effluvium).

4 January 2016 in Laboratory Medicine
Verified
Journal Article
Closed access
PDF file
AVAlen Vrtarić
Alen Vrtarić
PFPetra Filipi
Petra Filipi
MHMarina Hemar
Marina Hemar
NGNora Nikolac Gabaj
Nora Nikolac Gabaj
ASAna-Maria Simundic
Ana-Maria Simundic
Objective: To determine whether K2-ethylenediaminetetraacetic acid (EDTA) and K3-EDTA Greiner tubes could be used interchangeably for glycosylated hemoglobin, type A1C (HbA1c) measurement via the Abbott Laboratories ARCHITECT chemiluminescent microparticle HbA1c assay on the ARCHITECT i2000SR immunoanalyzer at our university hospital. Materials: We drew blood from a total of 45 outpatients into plastic Greiner Vacuette tubes, some of which were lined with K2-EDTA and others with K3-EDTA anticoagulant. Data are presented as median and interquartile range values. We used the Wilcoxon test and Passing-Bablok regression for tube comparison. Results: For K2-EDTA tubes median HbA1c concentration was 54 mmol/mol (41 to 71 mmol/mol) and for K3-EDTA tubes 56 mmol/mol (43 to 69 mmol/mol). There was no statistically significant difference between K2-EDTA and K3-EDTA (bias= -1.29 mmol/mol; P = 0.24). Passing-Bablok regression showed that there is no constant and proportional error: y = ‐0.23 (95% CI[-3.52 to 0.69]) + 1.00( 95% CI[0.98 to 1.06]) x. Conclusion: In this study, we provide evidence for the lack of any clinically and statistically significant bias between K2-EDTA and K3-EDTA HbA1c measurements. Thus, Greiner tubes lined with K2-EDTA and those lined with K3-EDTA can safely be used interchangeably to measure HbA1c via the Abbott Laboratories ARCHITECT assay.

15 February 2022 in Clinical Chemistry and Laboratory Medicine (CCLM)
Verified
Journal Article
Closed access
NGNora Nikolac Gabaj
Nora Nikolac Gabaj
MMMarijana Miler
Marijana Miler
AVAlen Vrtarić
Alen Vrtarić
IĆIvana Ćelap
Ivana Ćelap
MBMarina Bocan
Marina Bocan
MKMarija Kocijancic
Marija Kocijancic
Objectives: Hemolysis is associated with erroneous or delayed results. Objectives of the study were to compare four different methods for obtaining hemolysis in vitro on three different analyzers. Methods: Hemolysis was prepared with addition of pure hemoglobin into serum pool, osmotic shock, aspiration through blood collection needle, freezing/thawing of whole blood. Biochemistry parameters were measured in duplicate at Architect c8000 (Abbott, Abbott Park, USA), Beckman Coulter AU680 (Beckman Coulter, Brea, USA) and Cobas 6000 c501 (Roche, Mannheim, Germany), according to manufacturers’ declarations. Cut-off value was defined as the highest value of H index with corresponding bias lower than acceptance criteria. Results: We were not able to obtain results with freezing protocol. On all three platforms, lowest number of analytes were sensitive to hemolysis at H=0.5 using method of adding free hemoglobin. When osmotic shock was used, cut-off values for the most analytes were generally met at lower values. Hemolysis significantly interfered with measurement of potassium and lactate dehydrogenase (LD) at H=0.5 on all platforms. The most of the tested analytes had the lowest acceptable H index when aspiration method was used. At the low level of hemolysis (H=0.8) glucose, sodium, potassium, chloride, phosphate, and LD were affected on all analyzers, with some additional analytes depending on the manufacturer. Conclusions: Hemolysis interference differs on different analyzers and according to protocol for obtaining hemolysis. Aspiration method was generally the most sensitive to hemolysis interference, while addition of free Hb was the most resistant.


29 September 2025 in Clinical Chemistry and Laboratory Medicine (CCLM)
Verified
Journal Article
Closed access
AVAlen Vrtarić
Alen Vrtarić
MMMarijana Miler
Marijana Miler
NGNora Nikolac Gabaj
Nora Nikolac Gabaj
IĆIvana Ćelap
Ivana Ćelap
VVValentina Vidranski
Valentina Vidranski
MKMarija Kocijancic
Marija Kocijancic
Objectives: Hemolysis is a common preanalytical interference in clinical biochemistry, affecting up to 3.3 % of routine samples and contributing to approximately 60 % of rejected specimens. It results from the release of intracellular constituents, such as hemoglobin and potassium, into the plasma due to cell membrane disruption. This interference is often evaluated through hemolysis index (HI) thresholds defined by in vitro diagnostic (IVD) analyzers, but these thresholds may not align with clinical needs or biological variation. Methods: A descriptive study was conducted from February to April 2025, comparing the hemolysis interference data of 72 clinical chemistry analytes across five major manufacturers: Abbott, Beckman Coulter, BioSystems, Roche, and Siemens. Manufacturer package inserts were reviewed and compared to the CLSI C56-A guideline for hemolysis interference testing. Results: The compliance of manufacturers with the CLSI guideline varied significantly. Siemens had the highest compliance, reporting hemolysis interference at two analyte levels in 46/71 of cases, while BioSystems did not report analyte concentrations for any tested parameters. Criteria for significant interference was often missing, and in many cases, manufacturers used arbitrary thresholds, such as 10 % bias. Additionally, acceptance criteria and reported bias values were inconsistent across manufacturers, with only Abbott and Siemens providing detailed bias data. Conclusions: Manufacturer instructions often lack completeness and consistency, making it crucial for clinical laboratories to independently validate hemolysis thresholds. A harmonized approach, incorporating manufacturer data, research, and local validation, is essential to improve laboratory quality, minimize misinterpretations, and ensure compliance with regulatory standards.