Petar Brlek

Dr. Petar Brlek

Centre for Genomics and Personalized Medicine, St. Catherine's Specialty Hospital, Zagreb, Zagreb, Grad, Croatia
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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13 March 2024 in Cells
Verified
Journal Article
Open access
PDF file
Petar BrlekPetar Brlek
Petar Brlek
Luka BulićLuka Bulić
Luka Bulić
MBMatea Bračić
Matea Bračić
PPPetar Projić
Petar Projić
VSVedrana Skaro
Vedrana Skaro
Dragan PrimoracDragan Primorac
Dragan Primorac
The integration of whole genome sequencing (WGS) into all aspects of modern medicine represents the next step in the evolution of healthcare. Using this technology, scientists and physicians can observe the entire human genome comprehensively, generating a plethora of new sequencing data. Modern computational analysis entails advanced algorithms for variant detection, as well as complex models for classification. Data science and machine learning play a crucial role in the processing and interpretation of results, using enormous databases and statistics to discover new and support current genotype–phenotype correlations. In clinical practice, this technology has greatly enabled the development of personalized medicine, approaching each patient individually and in accordance with their genetic and biochemical profile. The most propulsive areas include rare disease genomics, oncogenomics, pharmacogenomics, neonatal screening, and infectious disease genomics. Another crucial application of WGS lies in the field of multi-omics, working towards the complete integration of human biomolecular data. Further technological development of sequencing technologies has led to the birth of third and fourth-generation sequencing, which include long-read sequencing, single-cell genomics, and nanopore sequencing. These technologies, alongside their continued implementation into medical research and practice, show great promise for the future of the field of medicine.

4 May 2022 in Frontiers in Immunology
Verified
Journal Article
Open access
Dragan PrimoracDragan Primorac
Dragan Primorac
KVKristijan Vrdoljak
Kristijan Vrdoljak
Petar BrlekPetar Brlek
Petar Brlek
EPEduard Pavelić
Eduard Pavelić
VMVilim Molnar
Vilim Molnar
MPMarijo Parčina
Marijo Parčina
Since the onset of the COVID-19 pandemic, the medical field has been forced to apply the basic knowledge of immunology with the most up-to-date SARS-CoV-2 findings and translate it to the population of the whole world in record time. Following the infection with the viral antigen, adaptive immune responses are activated mainly by viral particle encounters with the antigen-presenting cells or B cell receptors, which induce further biological interactions to defend the host against the virus. After the infection has been warded off, the immunological memory is developed. The SARS-CoV cellular immunity has been shown to persist even 17 years after the infection, despite the undetectable humoral component. Similar has been demonstrated for the SARS-CoV-2 T cell memory in a shorter period by assessing interferon-gamma levels when heparinized blood is stimulated with the virus-specific peptides. T cells also play an irreplaceable part in a humoral immune reaction as the backbone of a cellular immune response. They both provide the signals for B cell activation and the maturation, competence, and memory of the humoral response. B cell production of IgA was shown to be of significant influence in mediating mucosal immunity as the first part of the defense mechanism and in the development of nasal vaccines. Here, we interpret the recent SARS-CoV-2 available research, which encompasses the significance and the current understanding of adaptive immune activity, and compare it among naive, exposed, and vaccinated blood donors. Our recent data showed that those who recovered from COVID-19 and those who are vaccinated with EMA-approved vaccines had a long-lasting cellular immunity. Additionally, we analyze the humoral responses in immunocompromised patients and memory mediated by cellular immunity and the impact of clonality in the SARS-CoV-2 pandemic regarding breakthrough infections and variants of concern, both B.1.617.2 (Delta) and B.1.1.529 (Omicron) variants.

26 May 2022 in Genes
Verified
Journal Article
Open access
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Vilim MolnarVilim Molnar
Vilim Molnar
EPEduard Stjepan Pavelic
Eduard Stjepan Pavelic
KVKristijan Vrdoljak
Kristijan Vrdoljak
MČMartin Čemerin
Martin Čemerin
EKEmil Klarić
Emil Klarić
Dragan PrimoracDragan Primorac
Dragan Primorac
With the insufficient satisfaction rates and high cost of operative treatment for osteoarthritis (OA), alternatives have been sought. Furthermore, the inability of current medications to arrest disease progression has led to rapidly growing clinical research relating to mesenchymal stem cells (MSCs). The availability and function of MSCs vary according to tissue source. The three primary sources include the placenta, bone marrow, and adipose tissue, all of which offer excellent safety profiles. The primary mechanisms of action are trophic and immunomodulatory effects, which prevent the further degradation of joints. However, the function and degree to which benefits are observed vary significantly based on the exosomes secreted by MSCs. Paracrine and autocrine mechanisms prevent cell apoptosis and tissue fibrosis, initiate angiogenesis, and stimulate mitosis via growth factors. MSCs have even been shown to exhibit antimicrobial effects. Clinical results incorporating clinical scores and objective radiological imaging have been promising, but a lack of standardization in isolating MSCs prevents their incorporation in current guidelines.

29 June 2021 in Cancers
Verified
Journal Article
Open access
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Petar BrlekPetar Brlek
Petar Brlek
AKAnja Kafka
Anja Kafka
ABAnja Bukovac
Anja Bukovac
Nives Pecina-SlausNives Pecina-Slaus
Nives Pecina-Slaus
Diffuse gliomas are a heterogeneous group of tumors with aggressive biological behavior and a lack of effective treatment methods. Despite new molecular findings, the differences between pathohistological types still require better understanding. In this in silico analysis, we investigated AKT1, AKT2, AKT3, CHUK, GSK3β, EGFR, PTEN, and PIK3AP1 as participants of EGFR-PI3K-AKT-mTOR signaling using data from the publicly available cBioPortal platform. Integrative large-scale analyses investigated changes in copy number aberrations (CNA), methylation, mRNA transcription and protein expression within 751 samples of diffuse astrocytomas, anaplastic astrocytomas and glioblastomas. The study showed a significant percentage of CNA in PTEN (76%), PIK3AP1 and CHUK (75% each), EGFR (74%), AKT2 (39%), AKT1 (32%), AKT3 (19%) and GSK3β (18%) in the total sample. Comprehensive statistical analyses show how genomics and epigenomics affect the expression of examined genes differently across various pathohistological types and grades, suggesting that genes AKT3, CHUK and PTEN behave like tumor suppressors, while AKT1, AKT2, EGFR, and PIK3AP1 show oncogenic behavior and are involved in enhanced activity of the EGFR-PI3K-AKT-mTOR signaling pathway. Our findings contribute to the knowledge of the molecular differences between pathohistological types and ultimately offer the possibility of new treatment targets and personalized therapies in patients with diffuse gliomas.

14 March 2022 in Vaccines
Verified
Journal Article
Open access
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Dragan PrimoracDragan Primorac
Dragan Primorac
Petar BrlekPetar Brlek
Petar Brlek
VMVid Matišić
Vid Matišić
Vilim MolnarVilim Molnar
Vilim Molnar
KVKristijan Vrdoljak
Kristijan Vrdoljak
MPMarijo Parčina
Marijo Parčina
Previous clinical and epidemiological studies have shown that over time antibody titers decrease, and they do not provide long-term mucosa protection against SARS-CoV-2 infection. Additionally, the increase in breakthrough infections that occur more frequently in the vaccinated than in the study participants with previous SARS-CoV-2 infection has recently become a priority public health concern. We measured the amount of interferon-gamma (Quan-T-Cell ELISA) and the level of antibodies (Anti-SARS-CoV-2 QuantiVac ELISA IgG) in the blood of the same patients simultaneously to compare cellular and humoral immunity. A total of 200 study participants (before Omicron variant appearance) were divided into four groups whose levels of cellular and humoral immunity we compared: study participants previously infected with SARS-CoV-2 (group 1); study participants vaccinated with EMA-approved vaccines (group 2); study participants previously infected with SARS-CoV-2, and vaccination history (group 3); and study participants without a history of SARS-CoV-2 infection or vaccination (group 4). Our results showed that study participants who received one of the EMA-approved vaccines and who recovered from COVID-19 (group 3) had significantly higher levels of cellular immunity and antibody titers in comparison with groups 1 and 2. Additionally, we have noticed that the study participants previously infected with SARS-CoV-2 and the study participants vaccinated with EMA-approved vaccines had a long-lasting cellular immunity. Furthermore, antibody levels showed a negative correlation with time since the last contact with a viral antigen, while cellular immunity within 20 months showed as long-term protection. Moreover, out of 200 study participants, only 1 study participant who recovered from COVID-19 (0.5%) was re-infected, while a total of 6 study participants (3%) were infected with SARS-CoV-2 after receiving the vaccine. This study suggests that cellular immunity—unlike humoral immunity, thanks to memory T cells—represents long-term protection in individuals recovered from SARS-CoV-2 and after vaccination.

Verified
Journal Article
Open access
PDF file
Dragan PrimoracDragan Primorac
Dragan Primorac
Petar BrlekPetar Brlek
Petar Brlek
Luka BulićLuka Bulić
Luka Bulić
NHNenad Hrvatin
Nenad Hrvatin
VSVedrana Skaro
Vedrana Skaro
Ali MobasheriAli Mobasheri
Ali Mobasheri
Extracellular vesicles (EVs) have emerged as essential mediators of intercellular communication, transporting a complex repertoire of lipids, proteins, and nucleic acids that mirror the physiological and pathological status of their parent cells. This review provides a comprehensive overview of EVs from their biogenesis and molecular composition to their translational potential in human disease. This review outlines the major classes of EVs, including exosomes, microvesicles, apoptotic bodies, and oncosomes, together with recent developments in their isolation, molecular characterization, and omics-based profiling. Special focus is given to the role of EVs in viral infection, inflammation, and immune regulation, as well as their contribution to disease development and cancer biology. Moreover, we highlight the emerging clinical applications of mesenchymal stem cell-derived EVs (MSC-EVs) in regenerative medicine and oncology, alongside the therapeutic modulation of EV signaling by photobiomodulation (PBM). Finally, we address key translational challenges related to standardization, scalability, and regulatory validation. As exosome-based therapeutics fall under strict FDA and EMA oversight, their translation further depends on harmonized quality controls and robust safety evaluation. By integrating molecular mechanisms with clinical applications, this review emphasizes the transformative potential of EVs as next-generation diagnostic and therapeutic tools in precision medicine.