Antun Koprivanac

Dr. Antun Koprivanac

University hospital "Sveti Duh", Zagreb, Zagreb, Grad, Croatia
orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

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

Representative Publications

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25 October 2022 in Biomedicines
Verified
Journal Article
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PSPredrag Sikiric
Predrag Sikiric
MUMario Udovicic
Mario Udovicic
IBIvan Barisic
Ivan Barisic
DBDiana Balenović
Diana Balenović
GPGordana Zivanovic Posilovic Posilovic
Gordana Zivanovic Posilovic Posilovic
SSSven Seiwerth
Sven Seiwerth
In heart disturbances, stable gastric pentadecapeptide BPC 157 especial therapy effects combine the therapy of myocardial infarction, heart failure, pulmonary hypertension arrhythmias, and thrombosis prevention and reversal. The shared therapy effect occurred as part of its even larger cytoprotection (cardioprotection) therapy effect (direct epithelial cell protection; direct endothelium cell protection) that BPC 157 exerts as a novel cytoprotection mediator, which is native and stable in human gastric juice, as well as easily applicable. Accordingly, there is interaction with many molecular pathways, combining maintained endothelium function and maintained thrombocytes function, which counteracted thrombocytopenia in rats that underwent major vessel occlusion and deep vein thrombosis and counteracted thrombosis in all vascular studies; the coagulation pathways were not affected. These appeared as having modulatory effects on NO-system (NO-release, NOS-inhibition, NO-over-stimulation all affected), controlling vasomotor tone and the activation of the Src-Caveolin-1-eNOS pathway and modulatory effects on the prostaglandins system (BPC 157 counteracted NSAIDs toxicity, counteracted bleeding, thrombocytopenia, and in particular, leaky gut syndrome). As an essential novelty noted in the vascular studies, there was the activation of the collateral pathways. This might be the upgrading of the minor vessel to take over the function of the disabled major vessel, competing with and counteracting the Virchow triad circumstances devastatingly present, making possible the recruitment of collateral blood vessels, compensating vessel occlusion and reestablishing the blood flow or bypassing the occluded or ruptured vessel. As a part of the counteraction of the severe vessel and multiorgan failure syndrome, counteracted were the brain, lung, liver, kidney, gastrointestinal lesions, and in particular, the counteraction of the heart arrhythmias and infarction.

7 December 2023 in Pharmaceuticals
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Journal Article
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PSPredrag Sikiric
Predrag Sikiric
ABAlenka Boban Blagaic
Alenka Boban Blagaic
IKIvan Krezic
Ivan Krezic
HŽHelena Žižek
Helena Žižek
LKLuka Kalogjera
Luka Kalogjera
SSSven Seiwerth
Sven Seiwerth
We reviewed gastric ulcer healing by dopamine considering several distinctive duodenal key points. Selye and Szabo describe the cysteamine-induced duodenal ulcer in rats as a duodenal stress ulcer in patients. Szabo’s cysteamine duodenal ulcer as the dopamine duodenal healing and cysteamine as a dopamine antagonist signifies the dopamine agonists anti-ulcer effect and dopamine antagonists ulcerogenic effect. From these viewpoints, we focused on dopamine and gastric ulcer healing. We mentioned antecedent studies on the dopamine presence in the stomach and gastric juice. Then we reviewed, in the timeline, therapy significance arising from the anti-ulcer potency of the various dopamine agonists, which is highly prevailing over the quite persistent beneficial evidence arising from the various dopamine antagonists. Meanwhile, the beneficial effects of several peptides (i.e., amylin, cholecystokinin, leptin, and stable gastric pentadecapeptide BPC 157, suggested as an acting mediator of the dopamine brain-gut axis) were included in the dopamine gastric ulcer story. We attempt to resolve dopamine agonists/antagonists issue with the dopamine significance in the stress (cysteamine as a prototype of the duodenal stress ulcer), and cytoprotection (cysteamine in small dose as a prototype of the cytoprotective agents; cysteamine duodenal ulcer in gastrectomized rats). Thereby, along with dopamine agonists’ beneficial effects, in special circumstances, dopamine antagonists having their own ulcerogenic effect may act as “mild stress (or)” or “small irritant” counteracting subsequent strong alcohol or stress procedure-induced severe lesions in this particular tissue. Finally, in the conclusion, as a new improvement in further therapy, we emphasized the advantages of the dopamine agents’ application in lower gastrointestinal tract therapy.

22 January 2026 in Pharmaceuticals
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Journal Article
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ISIvan Maria Smoday
Ivan Maria Smoday
VVVlasta Vukovic
Vlasta Vukovic
KOKatarina Oroz
Katarina Oroz
Hrvoje VranesHrvoje Vranes
Hrvoje Vranes
LKLuka Kalogjera
Luka Kalogjera
ASAnita Skrtic
Anita Skrtic
Background: No Fourier transform infrared (FTIR) spectroscopy studies have directly evaluated adrenalectomy vessels, the technique’s established ability to probe collagen/elastin-associated spectral features and lipid peroxidation-related signatures, and protein structural damage. Stable gastric pentadecapeptide BPC 157 therapy was found to maintain the vascular function under severe stress, as FTIR spectroscopy recently demonstrated rapid peptide-induced molecular changes in healthy rat blood vessels, particularly in lipid content and protein secondary structure. Methods: To extend these findings and highlight the BPC 157 vascular background in the special circumstances of the course following unilateral adrenalectomy, abdominal aortas were collected at 15 min, 5 h, and 24 h after unilateral adrenalectomy for the FTIR spectroscopy assessment. Results: FTIR spectra were acquired, preprocessed, and analyzed using principal component analysis (PCA), support vector machine discriminant analysis (SVMDA), and band-specific statistics. BPC 157 (10 ng/kg intragatrically immediately after unilateral adrenalectomy) produced a clear, reproducible separation of aortic spectra from control samples at all time points. The main discriminatory spectral signatures were observed in three regions, including amide I and amide II (protein-related bands, consistent with collagen/elastin contributions) and lipid C–H stretching bands. These spectral signatures are consistent with early extracellular matrix reinforcement and membrane preservation in the vascular wall and align with the recovering effect on the lesions in counteraction of the severe vascular and multiorgan failure, attenuation/elimination of thrombosis and blood pressure disturbances in various occlusion/occlusion-like syndromes. Conclusions: Together, after unilateral adrenalectomy, the FTIR data provide molecular-level spectral signatures consistent with rapid remodeling of the aortic wall toward a more structurally stable and functionally favorable state.

14 January 2026 in Pharmaceuticals
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Journal Article
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GMGoran Madžarac
Goran Madžarac
TBTomislav Becejac
Tomislav Becejac
TPToni Penovic
Toni Penovic
DDDominik Drazenovic
Dominik Drazenovic
LKLucija Kralj
Lucija Kralj
PSPredrag Sikiric
Predrag Sikiric
Background/Objectives: This 7-day rat tracheocutaneous fistula study considered the not-studied issues of tracheocutaneous fistula course, wound healing, and fistula in the NO-system relations. Therefore, we focused on fistulas’ severe course, tracheocutaneous fistula → air leak → compensatory diaphragmatic/abdominal “heaving”, NO-system failed relations, and therapy resolution. Stable gastric pentadecapeptide BPC 157 was proposed. Methods: Tracheocutaneous fistula rats received daily medication (/kg), alone or combined, BPC 157 therapy (10 µg, 10 ng, in drinking water or intraperitoneally) along with a triple NO-agent approach (L-NAME 5 mg, L-arginine 100 mg, and L-NAME+L-arginine, intraperitoneally). Results: Tracheocutaneous fistulas occurred as specific and NO-system-related as follows: NO system: blockade (L-NAME-aggravation) over-activity (L-arginine-amelioration) or immobilization (L-NAME+L-arginine oppose each other’s effects). Controls presented severe clinical signs of respiratory distress, failed healing, skin and tracheal defects, a not-healed and open, macro/microscopically, and fistulous tract that was well-formed and wide, tracheal shrinking below the fistula, and clinically, open-mouth breathing, “heaving abdomen”, cyanosis (bluish snout, ears, extremities), abundant secretion through the fistula, and weight loss. Fistula tissue NO level decreased, and the malondialdehyde (MDA) level increased. The BPC 157 therapy (both application routes) resulted in rapid recovery. Healing of defects (skin and trachea) and fistula closure, macro/microscopically, corresponded with clinical findings, avoiding observable clinical signs of dyspnea, reducing weight loss, and avoiding any sign of “heaving abdomen”. BPC 157-treated rats displayed regular breathing movements without observable signs of respiratory distress. Finally, when combined, BPC 157 therapy upgrades L-arginine amelioration, abolishes L-NAME-induced worsening, and restores full healing after NO immobilization (L-NAME+L-arginine). BPC 157 counteracted increase in NO level and counteracted increase in MDA level. Conclusions: Thus, first, acting systemically, BPC 157 reverses tracheocutaneous fistula course in rats. It acts through the NO system.

30 May 2026 in Pharmaceuticals
Verified
Journal Article
Open access
PDF file
ISIvan Maria Smoday
Ivan Maria Smoday
VVVlasta Vukovic
Vlasta Vukovic
KOKatarina Oroz
Katarina Oroz
Hrvoje VranesHrvoje Vranes
Hrvoje Vranes
LKLuka Kalogjera
Luka Kalogjera
ASAnita Skrtic
Anita Skrtic
Background. This rat study reveals a new point: the considerable impact of unilateral adrenalectomy, severe vascular and multiorgan failure, occlusion/occlusion-like syndrome, and the stable gastric pentadecapeptide BPC 157 therapy. Based on the recent Fourier transform infrared (FTIR) spectroscopy vascular disturbance studies, particularly those after unilateral adrenalectomy in rats, the noted cytoprotective vascular recovery effect of the BPC 157 therapy may be useful. Methods. In rats, unilateral adrenalectomy (at 15 min, 5 h, 24 h) leads to integrated gross and morphological changes, vascular alterations, oxidative stress parameters, molecular markers and occlusion/occlusion-like syndrome and BPC 157 as useful therapy (/kg ig) (10 µg, 10 ng). Results. Peripherally and centrally, counteraction includes the lesions (adrenal, brain, heart, lung, liver, kidney, gastrointestinal tract), organ hemorrhage, and thrombosis. Attenuated/eliminated were arrhythmias, intracranial (superior sagittal sinus), portal, caval hypertension, and aortic hypotension. Significant resolution occurred via activation of collateral pathways, the azygos vein (direct blood flow delivery), and the recovered peduncle of the inferior suprarenal artery and superior suprarenal vein. Virchow’s triad circumstances were reversed. Occlusion/occlusion-like syndrome was counteracted as a whole. Also, BPC 157 counteracted adrenal lesions (lipid depletion, congestion). There were higher cortisol values, but still very low, and a shift toward the left of the adrenal compensatory weight increase. For the indicative conclusion along with previous studies, mechanistically, BPC 157 therapy exhibits the NO-system modulation/oxidative stress balance, increases NO-level, counteracts oxidative stress (malondialdehyde (MDA)), upregulates NOS1–3, and VEGF-A expression. Conclusions. These effects of BPC 157 therapy and its easy applicability deserve further consideration.

2 December 2025 in Kidney360
Verified
Journal Article
Open access
IMIvana Mikačić
Ivana Mikačić
Antun KoprivanacAntun Koprivanac
Antun Koprivanac
MCMarijana Coric
Marijana Coric