Irena Krznaric-Zrnic

Irena Krznaric-Zrnic

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Irena Krznaric-Zrnic has a total of 81 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Immune-Mediated Colitis Induced by Immune Checkpoint Inhibitors: Pathophysiology, Clinical Management, and the Emerging Role of Fecal Microbiota Transplantation

    by Zeljka Belosic Halle, Vedran Tomasic, Alen Biscanin, Petra Cacic, Ivona Saric, Sanda Mustapic, Josip Stojic, Kresimir Luetic, Dinko Bekic, Matej Paic, et al.

    Background/Objectives: Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of various malignancies, but their use is frequently accompanied by immune-related adverse events, among which immune-mediated colitis (IMC) represents one of the most common and clinically significant gastrointestinal toxicities. IMC may lead to treatment interruption, increased morbidity, and compromised quality of life. This review aims to provide a comprehensive overview of the pathophysiology, risk factors, diagnosis, management, and emerging therapeutic strategies with particular emphasis on the role of the gut microbiota and fecal microbiota transplantation (FMT). Methods: This review integrates current international guidelines, meta-analyses, clinical trials, and recent translational studies addressing IMC. The available evidence on immunological mechanisms, predictive biomarkers, clinical presentation, diagnostic algorithms, and treatment options was critically synthesized to outline a structured and multidisciplinary management approach. Results: IMC is driven by dysregulated immune activation, cytokine release, and alterations in gut microbiota. Incidence and severity vary according to ICI class, combination regimens, tumor type, and patient-related factors. Diagnosis requires exclusion of infectious causes, laboratory assessment, and endoscopic and histologic evaluation with CTCAE-based severity grading. Corticosteroids remain the cornerstone of first-line therapy, while infliximab and vedolizumab are effective in steroid-refractory cases. Emerging therapies, including JAK inhibitors and FMT, have shown promising results in refractory disease. Conclusions: IMC is a complex and potentially severe complication of ICI therapy that necessitates early recognition, accurate grading, and individualized, multidisciplinary management. Severity-guided treatment, timely escalation to biologics, and careful balancing of immunosuppression with antitumor efficacy are essential for optimal outcomes. Future research should focus on biomarker validation, microbiome-targeted therapies, and prospective trials to refine therapeutic algorithms and define the optimal role and timing of FMT in clinical practice.

  • Open Access

    Fecal Microbiota Transplantation in Refractory Immune-Mediated Colitis: Case Series and Review of the Literature

    by Marin Golčić, Laura Radoš, Iva Skočilić, Ivona Badovinac, Goran Hauser, Irena Krznarić Zrnić, Marina Šantić, Dora Fučkar Čupić, Sara Francetić, Karla Lisica, et al.

    Background/Objectives: Immune checkpoint inhibitors (ICI) represent a significant breakthrough in cancer management, but they can cause adverse effects such as immune-mediated colitis (IMC). The standard first-line treatment is corticosteroids, and second-line treatment is infliximab or vedolizumab. However, a proportion of immune-mediated colitis (IMC) cases are refractory to immunosuppressive treatment, which has led to the exploration of novel approaches such as fecal microbiota transplantation. Methods: We present two patients who both developed grade III IMC following application of durvalumab and pembrolizumab, respectively. Both patients were refractory to corticosteroid therapy, while the first one also showed no improvement to infliximab. We performed two separate applications of FMT on both patients, from different donors, as a rescue treatment. Results: After unsuccessful immunosuppressive treatment and following rescue FMT, both patients demonstrated a rapid and sustained improvement in inflammatory markers, clinical symptoms, quality-of-life scores, and colonoscopy findings, without additional immunosuppressive treatment. Conclusions: FMT appears to be safe and a potentially effective treatment option for patients with refractory IMC both as second- and third-line therapy options. Continued efforts toward rigorous donor screening, use of standardized biobanks, and standardizing FMT protocols will further enhance safety and reproducibility.


  • Open Access

    Intestinal Microbiota Modulation by Fecal Microbiota Transplantation in Nonalcoholic Fatty Liver Disease

    by Goran Hauser, Indira Benjak Horvat, Mirjana Rajilić-Stojanović, Irena Krznarić-Zrnić, Michail Kukla, Vedrana Aljinović-Vučić, Ivana Mikolašević

    Numerous factors are involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD), which are responsible for its development and progression as an independent entity, but also thanks to their simultaneous action. This is explained by the hypothesis of multiple parallel hits. These factors are insulin resistance, lipid metabolism alteration, oxidative stress, endoplasmic reticulum stress, inflammatory cytokine liberation, gut microbiota dysbiosis or gut–liver axis activation. This is a systematic review which has an aim to show the connection between intestinal microbiota and the role of its disbalance in the development of NAFLD. The gut microbiota is made from a wide spectrum of microorganisms that has a systemic impact on human health, with a well-documented role in digestion, energy metabolism, the stimulation of the immune system, synthesis of essential nutrients, etc. It has been shown that dysbiosis is associated with all three stages of chronic liver disease. Thus, the modulation of the gut microbiota has attracted research interest as a novel therapeutic approach for the management of NAFLD patients. The modification of microbiota can be achieved by substantial diet modification and the application of probiotics or prebiotics, while the most radical effects are observed by fecal microbiota transplantation (FMT). Given the results of FMT in the context of metabolic syndrome (MetS) and NAFLD in animal models and scarce pilot studies on humans, FMT seems to be a promising treatment option that could reverse intestinal dysbiosis and thereby influence the course of NAFLD.


  • Open Access

    A Multiparametric Method Improves the Serological Characterization of Inflammatory Bowel Diseases: Preliminary Results from a Multicenter Eastern Europe Study

    by Nikola Panic, Marco Marino, Goran Hauser, Silvia Jacobsen, Francesco Curcio, Francesco Meroi, Adriana Cifù, Eleonora Castagnaviz, Cinzia Pistis, Giovanni Terrosu, et al.

    The serological support for early diagnosis and differential diagnosis of inflammatory bowel diseases (IBDs) is actually very limited. In this study, we evaluated the performance of a promising multiparametric method including either well-established and newly developed biomarkers. We conducted a multicenter cross-sectional study at the Gastroenterology Units of Udine (Italy), Rijeka (Croatia) and Belgrade (Serbia). Sera was collected from IBD patients, and autoantibody profiles were determined using a mosaic cell and tissue-based indirect immunofluorescence (IIF) method simultaneously investigating anti-saccharomyces cerevisiae antibodies (ASCAs), anti-atypical perinuclear neutrophilic antibodies (P-ANCAs), anti-pancreatic antigens antibodies (PABs) and anti-goblet cells antibodies (GAB). The study finally enrolled 156 patients with IBD: 100 affected by Crohn’s disease (CD) and 56 by ulcerative colitis (UC). Twenty age-sex matched blood donors (BDs) were included as controls. PAB (anti-CUZD1 and/or anti-GP2 antibodies) were present in 24 CD patients versus none of the UC patients or BDs (24% sensitivity, 100% specificity). As regards CD patients, combined positivity of PAB and ASCA (sensitivity 84%, specificity 71.4%) performed better than ASCA alone. Colon involvement (87.5% vs. 60.5%; p = 0.014), deep mucosal lesions (58.3% vs. 25.0%; p = 0.002) and need for biologic therapies (79.2% vs. 46.1%; p = 0.005) were significantly more prevalent in PAB-positive than in PAB-negative CD patients. Multivariate analysis identified PAB positivity (OR = 3.67; 95%CI = 1.29–10.46) and anti-CUZD1 in particular (OR = 3.54; 95%CI = 1.08–11.63) as significant risk factors for deep mucosal lesion development in CD. A multiparametric diagnostic approach appears very useful to better characterize IBD patients. PABs, whether isolated or combined with other autoantibodies, may support differential diagnosis but above all facilitate the selection of CD patients at risk for more severe disease.


  • Open Access

    A Multiparametric Method Improves the Serological Characterization of Inflammatory Bowel Diseases: Preliminary Results from a Multicenter Eastern Europe Study

    by Nikola Panic, Marco Marino, Goran Hauser, Silvia Jacobsen, Francesco Curcio, Francesco Meroi, Adriana Cifù, Eleonora Castagnaviz, Cinzia Pistis, Giovanni Terrosu, et al.

    Introduction: The serological support to early diagnosis and differential diagnosis of inflammatory bowel diseases (IBD) is actually very limited. In this study we evaluated the performance of a promising multiparametric method including either well established and newly developed biomarkers. Methods: This multicenter retrospective observational study finally enrolled 156 patients with IBD, 100 affected by Crohn’s disease (CD) and 56 by ulcerative colitis (UC) recruited at the Gastroenterology Units of Udine (Italy), Rijeka (Croatia) and Belgrade (Serbia). Twently age-sex matched blood donors (BD) were included as controls. Autoantibody profiles were determined using a mosaic cell and tissue-based indirect immunofluorescence (IIF) method simultaneously investigating: anti-saccharomyces cerevisiae antibodies (ASCA), anti-atypical perinuclear neutrophilic antibodies (P-ANCA), anti-pancreatic antigens antibodies (PAB) and anti-goblet cells antibodies (GAB). Results: PAB (anti-CUZD1 and/or anti-GP2 antibodies) were present in 24 CD patients versus none of UC patients or BD (24% sensitivity, 100% specificity). As regards CD patients, combined positivity of PAB and ASCA (sensitivity 84%, specificity 71.4%) performed better than ASCA alone. Colon involvement (87.5% vs. 60.5%; p=0.014), deep mucosal lesions (58.3% vs. 25.0%; p=0.002) and need for biologic therapies (79.2% vs. 46.1%; p=0.005) were significantly more prevalent in PAB-positive than in PAB-negative CD patients. Multivariate analysis identified PAB positivity (OR=3.67; 95%CI=1.29-10.46) and anti-CUZD1 in particular (OR=3.54; 95%CI=1.08-11.63) as significant risk factors for deep mucosal lesions development in CD. Conclusion: A multiparametric diagnostic approach appears very useful to better characterize IBD patients. PAB, isolated or combined with other autoantibodies, may support both differential diagnosis and selection of CD patients at risk for more severe disease.

  • Open Access

    The Accuracy of Serum Biomarkers in the Diagnosis of Steatosis, Fibrosis, and Inflammation in Patients with Nonalcoholic Fatty Liver Disease in Comparison to a Liver Biopsy

    by Ivana Mikolasevic, Viktor Domislovic, Irena Krznaric-Zrnic, Zeljko Krznaric, Lucija Virovic-Jukic, Sanja Stojsavljevic, Ivica Grgurevic, Sandra Milic, Ivan Vukoja, Petra Puz, et al.

    Background and Objective: This study was conducted to evaluate the diagnostic performance of various biomarkers for steatosis, fibrosis, and inflammation in comparison to a liver biopsy (LB) in patients with nonalcoholic fatty liver disease (NAFLD). Materials and Methods: This was a cross-sectional study that included 135 patients with biopsy-proven NAFLD. Fatty liver index (FLI), hepatic steatosis index (HSI), cell death markers (CK-18 M30 and CK-18 M65), FIB-4 index, NAFLD fibrosis score (NFS), BARD, and AST to platelet ratio index (APRI) were calculated and analysed. Results: FLI, HSI scores, and the cell death biomarkers showed poor diagnostic accuracy for steatosis detection and quantification, with an area under the curve (AUC) of 0.7) for advanced fibrosis, whereas FIB-4, BARD, and NFS scores demonstrated poor performance (AUC < 0.70). However, a combination of FIB-4 and NFS with the cell death biomarkers had moderate accuracy for advanced (≥F3) fibrosis detection, with an AUC of >0.70. Conclusions: In this first study on Croatian patients with NAFLD, serum biomarkers demonstrated poor diagnostic performance for the noninvasive diagnosis of liver steatosis and NASH. APRI and the cell death biomarkers had only moderate accuracy for diagnosing advanced fibrosis, as did the combination of FIB-4 and NFS with the cell death biomarkers. Further studies regarding serum biomarkers for all NAFLD stages are needed.


  • Accuracy of Controlled Attenuation Parameter and Liver Stiffness Measurement in Patients with Non-alcoholic Fatty Liver Disease

    by Ivana Mikolasevic, Viktor Domislovic, Mia Klapan, Toni Juric, Andjela Lukic, Irena Krznaric-Zrnic, Dora Fuckar-Cupic, Davor Stimac, Tajana Filipec Kanizaj, Zeljko Krznaric, et al.


  • Open Access

    Nonalcoholic steatohepatitis: emerging targeted therapies to optimize treatment options

    by Sandra Milić, Ivana Mikolasevic, Irena Krznaric-Zrnic, Marija Stanic, Goran Poropat, Davor Stimac, Vera Vlahovic-Palcevski, Lidija Orlic

    Diet and lifestyle changes have led to worldwide increases in the prevalences of obesity and metabolic syndrome, resulting in substantially greater incidence of nonalcoholic fatty liver disease (NAFLD). NAFLD is considered a hepatic manifestation of metabolic syndrome and is related to diabetes, insulin resistance, central obesity, hyperlipidemia, and hypertension. Nonalcoholic steatohepatitis (NASH) is an entity that describes liver inflammation due to NAFLD. Growing evidence suggests that NAFLD is a multisystem disease with a clinical burden that is not only confined to liver-related morbidity and mortality, but that also affects several extra-hepatic organs and regulatory pathways. Thus, NAFLD is considered an important public health issue, but there is currently no effective therapy for all NAFLD patients in the general population. Studies seeking optimal therapy for NAFLD and NASH have not yet led to development of a universal protocol for treating this growing problem. Several pharmacological agents have been studied in an effort to improve insulin resistance and the proinflammatory mediators that may be responsible for NASH progression. Cardiovascular risk factors are highly prevalent among NASH patients, and the backbone of treatment regimens for these patients still comprises general lifestyle interventions, including dietary changes and increased physical activity. Vitamin E and thiazolidinedione derivatives are currently the most evidence-based therapeutic options, but only limited clinical evidence is available regarding their long-term efficacy and safety. Vitamin D and renin–angiotensin–aldosterone system blockers are promising drugs that are currently being intensively investigated for use in NAFLD/NASH patients.


  • Open Access

    Epidemiology of Acute Pancreatitis in the North Adriatic Region of Croatia during the Last Ten Years

    by Davor Stimac, Ivana Mikolasevic, Irena Krznaric-Zrnic, Mladen Radic, Sandra Milic

    Introduction. Several European studies have reported an increase in the incidence rate of acute pancreatitis (AP). Therefore, we studied the incidence rate of AP in the North Adriatic Region in Croatia, as well as epidemiological analysis concerning etiology, age, gender, and severity of disease. Methods. We analyzed 922 patients with confirmed diagnosis of AP (history, clinical and laboratory findings, and imaging methods) admitted to our hospital during a ten-year period (20002009). Epidemiological analysis was carried out focusing on incidence, demographic data, and etiology, as well as severity of the disease based on the Ranson and APACHE II scores. Results. The incidence rate varied from 24 to 35/100 000 inhabitants annually. Mean age was years. There were 53% men and 47% women among the patients. Most frequent etiologies of AP were biliary stones in 60% and alcohol abuse in 19% of patients. According to the Ranson and APACHE II scores, pancreatitis was considered to be severe in 50% and 43% of the cases, respectively. Conclusion. In our region the incidence of AP was around 30 per 100,000 population per year during the ten-year period studied. The mean age at admission was 60 years and etiology was predominantly biliary. In our region, we have shown epidemiological characteristics of AP typical for Mediterranean countries.


  • The Role of Nonenhanced Magnetic Resonance Imaging in the Early Assessment of Acute Pancreatitis

    by Davor Štimac, Damir Miletić, Mladen Radić, Irena Krznarić, Marzena Mazur-Grbac, Domagoj Perković, Sandra Milić, Vesna Golubović

    Computed tomography (CT), especially contrast-enhanced CT (CECT), provides important information on the severity and prognosis of acute pancreatitis (AP). Magnetic resonance imaging (MRI) has become a useful tool as an alternative to CT in the assessment of AP. The primary aim of our study was to determine the diagnostic value of nonenhanced MRI (NEMRI) to assess severity and predict outcome in patients with AP from the third to fifth day after admission. We also correlated MRI findings with CT and biochemical parameters. The study included 101 patients (49 men, 52 women, median age 62 yr, range 20-82) with a diagnosis of AP admitted to our hospital between January 1, 2004 and June 31, 2005. The inclusion criteria consisted of a combination of clinical features, a typical case history, elevation of serum pancreatic enzymes, and diagnosis confirmed by imaging studies. Contrast-enhanced spiral CT exams were performed in all patients from the third to fifth day after admission, and Balthazar grade and CT severity index were calculated. All patients underwent NEMRI, and MR severity index (MRSI) was calculated. We also performed magnetic resonance cholangiopancreatography (MRCP) in all patients to detect bile duct lithiasis. Significant correlation between CECT and NEMRI was found for Balthazar grade (P<0.001) and the assessment of pancreatic necrosis (P<0.001), as well as between the combined severity indices (rho=0.819, P<0.001). MRSI correlated with Ranson score (rho=0.656, P<0.01), C-reactive protein (CRP) levels 48 h after admission (rho=0.502, P<0.01), appearance of systemic complications (rho=0.576, P<0.01), and length of hospital stay (rho=0.484, P<0.01). Considering the Atlanta criteria as the gold standard and the Ranson score, no difference in sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the two methods was observed. Comparing the group of patients with presumed acute pancreatic hemorrhage with the group of patients with severe AP, we found a significantly higher APACHE II score on the first day (P<0.05), that the development of systemic complications was more frequent (P < 0.05), and that the hospital stay and ICU management of patients with MRI signs of pancreatic hemorrhage tended to be longer. NEMRI is comparable to CECT in the early assessment of the severity of AP, and both methods are equally efficient in predicting local and systemic complications of AP. MRI has a potential advantage over CT in detecting bile duct lithiasis and pancreatic hemorrhage.