Predrag Sikiric
University of Zagreb
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Featured researches published by Predrag Sikiric.
European Journal of Pharmacology | 1997
Predrag Sikiric; Sven Seiwerth; Željko Grabarević; Rudolf Rucman; Marijan Petek; Vjekoslav Jagić; Branko Turkovic; Ivo Rotkvic; Stjepan Mise; Ivan Zoricic; Paško Konjevoda; Darko Perovic; Ljubica Jurina; Jadranka Separovic; Miro Hanževački; Branka Artuković; Mirna Bratulić; Marina Tišljar; Miro Gjurašin; Pavao Miklić; Dinko Stančić-Rokotov; Zoran Slobodnjak; Nikola Jelovac; Anton Marovic
The known effects of a novel stomach pentadecapeptide BPC157 (10 microg or 10 ng/kg), namely its salutary activity against ethanol (96%, i.g.)-induced gastric lesions (simultaneously applied i.p.) and in blood pressure maintenance (given i.v.), were investigated in rats challenged with a combination of N(G)-nitro-L-arginine methylester (L-NAME) (5 mg/kg i.v.), a competitive inhibitor of endothelium nitric oxide (NO)-generation and NO precursor, L-arginine (200 mg/kg i.v.) (D-arginine was ineffective). In the gastric lesions assay, NO agents were given 5 min before ethanol injury and BPC 157 medication. Given alone, BPC157 had an antiulcer effect, as did L-arginine, but L-NAME had no effect. L-NAME completely abolished the effect of L-arginine, whereas it only attenuated the effect of BPC 157. After application of the combination of L-NAME + L-arginine, the BPC157 effect was additionally impaired. In blood pressure studies, compared with L-arginine, pentadecapeptide BPC 157 (without effect on basal normal values) had both a mimicking effect (impaired L-NAME-blood pressure increase, when applied prophylactically and decreased already raised L-NAME values, given at the time of the maximal L-NAME-blood pressure increase (i.e., 10 min after L-NAME)) and preventive activity (L-arginine-induced moderate blood pressure decrease was prevented by BPC 157 pretreatment). When BPC 157 was given 10 min after L-NAME + L-arginine combination, which still led to a blood pressure increase, its previously clear effect (noted in L-NAME treated rats) disappeared. In vitro, in gastric mucosa from rat stomach tissue homogenates, BPC 157, given in the same dose (100 microM) as L-arginine, induced a comparable generation of NO. But, BPC 157 effect could not be inhibited by L-NAME, even when L-NAME was given in a tenfold (100 versus 1000 microM) higher dose than that needed for inhibition of the L-arginine effect. NO synthesis was blunted when the pentadecapeptide BPC 157 and L-arginine were combined. In summary, BPC 157 could interfere with the effects of NO on both gastric mucosal integrity and blood pressure maintenance in a specific way, especially with L-arginine, having a more prominent and/or particularly different effect from that of NO.
Life Sciences | 1994
Predrag Sikiric; Sven Seiwerth; Zeljko Grabarevic; Marijan Petek; Rudolf Rucman; Branko Turkovic; Ivo Rotkvic; Vjekoslav Jagić; Marko Duvnjak; Stjepan Mise; Sanja Djačić; Jadranka Separovic; Marija Veljača; Ahmet Sallmani; Marko Banić; Tomislav Brkić
The protection of stomach and duodenum in conjecture with anti-inflammatory effect was demonstrated for a novel 15 amino acid peptide, coded BPC 157, a fragment of the recently discovered gastric juice peptide BPC. BPC 157 (i.p./i.g.) was investigated in rats in comparison with several reference standards in three experimental ulcer models (48 h-restraint stress, subcutaneous cysteamine, intragastrical 96% ethanol ulcer tests) (pre-/co-/post-treatment). Only BPC 157 regimens were consistently effective in all of the tested models. On the other hand, bromocriptine, amantadine, famotidine, cimetidine and somatostatin were ineffective (restraint stress). A dose-dependent protection (cysteamine) and/or partial positive effect (related to treatment conditions) (ethanol), was obtained with glucagon, NPY and secretin whereas CCK/26-30/was not effective. Based on Monastral blue studies BPC 157 beneficial effect appears to be related to a strong endothelial protection.
Digestive Diseases and Sciences | 1996
Predrag Sikiric; Sven Seiwerth; Željko Grabarević; Rudolf Rucman; Marijan Petek; Vjekoslav Jagić; Branko Turkovic; Ivo Rotkvic; Stjepan Mise; Ivan Zoricic; Miroslav Gjurasin; Paško Konjevoda; Jadranka Separovic; Danica Ljubanović; Branka Artuković; Mirna Bratulić; Marina Tišljar; Ljubica Jurina; Gojko Buljat; Pavao Miklić; Anton Marovic
Very recently, the integrity of capsaicin somatosensory neurons and their protection were suggested to be related to the activity in nociception of a newly discovered 15-amino acid peptide, BPC 157, shown to have strong beneficial effect on intestinal and liver lesions. Therefore, from this viewpoint, we have studied the gastroprotective effect of the pentadecapeptide BPC 157, on gastric lesions produced in rats by 96% ethanol, restraint stress, and indomethacin. The possible involvement of sensory neurons in the salutary actions of BPC 157 (10µg/kg, 10 ng/kg intraperitoneally) was studied with capsaicin, which has differential effects on sensory neurons: a high dose in adult (125 mg/kg subcutaneously, 3 months old) or administration (50 mg/kg subcutaneously) to neonatal animals (age of the 7 days) destroys sensory fibers, whereas a low dose (500µg/kg intraperitoneally) activates neurotransmitter release and protective effects on the mucosa. In the absence of capsaicin, BPC 157 protected gastric mucosa against ethanol, restraint, and indomethacin application. In the presence of neurotoxic doses of capsaicin, the negative influence of capsaicin on restraint, ethanol, or indomethacin lesions consistently affected salutary activity of BPC 157. However, BPC 157 protection was still evident in the capsaicin-treated rats (either treated as adults or as newborns) in all of these assays. Interestingly, after neonatal capsaicin treatment, a complete abolition of BPC gastroprotection was noted if BPC 157 was applied as a single nanogram-regimen, but the mucosal protection was fully reversed when the same dose was used daily. In line with the excitatory dose of capsaicin the beneficial effectiveness of BPC 157 appears to be increased as well. Taken together, these data provide evidence for complex synergistic interaction between the beneficial effectiveness of BPC 157 and peptidergic sensory afferent neuron activity.
Life Sciences | 1993
Predrag Sikiric; Sven Seiwerth; Zeljko Grabarevic; Rudolf Rucman; Marijan Petek; Ivo Rotkvic; Branko Turkovic; Vjekoslav Jagić; Boris Mildner; Marko Duvnjak; Zarko Danilović; Marko Kolega; Ahmet Sallmani; Sanja Dacic; Milan Dodig; Nada Lang; Jadranka Separovic; V. Corić; Velimir Šimičević; Krešimir Bulić; Marija Veljača; Nevena Skroza; Marko Banić; Tomislav Brkić; Gojko Buljat; Stjepan Mise; Drazen Lucinger; Miljenko Bura
The hepatoprotective effects of a newly synthesized 15 amino acid fragment code named BPC 157 was evaluated in comparison with the reference standards (bromocriptine, amantadine and somatostatin) in various experimental models of liver injury in rats: 24 h-bile duct+hepatic artery ligation 48 h-restraint stress and CCl4 administration. BPC 157 administered either intragastrically or intraperitoneally, significantly prevented the development of liver necrosis or fatty changes in rats subjected to 24 h bile duct + hepatic artery ligation, 48 h-restraint stress, CCl4 treatment (1 ml/kg i.p., sacrifice 48 h thereafter). The other reference drugs had either little or no protective actions in these models. Noteworthy, the laboratory test results for bilirubin, SGOT, SGPT fully correlated with the macro/microscopical findings. Thus, on the basis of consistent protective effect of BPC 157, possible clinical application in liver diseases is now warranted.
Journal of Physiology-paris | 1997
Sven Seiwerth; Predrag Sikiric; Zeljko Grabarevic; Ivan Zoricic; Miroslav Hanzevacki; D Ljubanovic; V Coric; Paško Konjevoda; Marijan Petek; Rudolf Rucman; Branko Turkovic; Darko Perovic; Darko Mikus; S Jandrijevic; M Medvidovic; T Tadic; B Romac; J Kos; J Peric; Z Kolega
The 15 amino acid agent BPC 157, showing a wide range of organoprotective action in different experimental models, was used in our experiments in order to establish its influence on different elements connected with the healing process. Elements thought to be of greatest importance in the process of healing are formation of granulation tissue, angiogenesis and production of collagen. In our work we tested the influence of BPC 157 on: granulation tissue and collagen formation, on angiogenesis as well as on tensile strength development, using three experimental rat models: 1) skin incisional wounds; 2) colon-colon anastomoses; and 3) angiogenesis model with synthetic sponge implantation. The specimens were histologically assessed for collagen, reticulin and blood vessels using scoring and morphometry. In all experiments significant differences between BPC 157-treated animals and controls were found, showing a strong, promoting involvement of BPC in the healing process. It is worth noting that these effects were achieved by different routes of application, including intragastric and local, making BPC 157 a potentially useful therapeutic agent.
Journal of Orthopaedic Research | 2003
Mario Staresinic; Bozidar Sebecic; Leonardo Patrlj; S. Jadrijevic; Slaven Suknaić; Darko Perovic; Gorana Aralica; N. Zarkovic; S. Borovic; M. Srdjak; K. Hajdarevic; M. Kopljar; Lovorka Batelja; Alenka Boban-Blagaic; I. Turcic; Tomislav Anic; Sven Seiwerth; Predrag Sikiric
In studies intended to improve healing of transected Achilles tendon, effective was a stable gastric pentadecapeptide BPC 157 (GEPPPGKPADDAGLV, M.W. 1419). Currently in clinical trials for inflammatory bowel disease (PLD‐116, PL 14736, Pliva), it ameliorates internal and external wound healing. In rats, the right Achilles tendon transected (5 mm proximal to its calcaneal insertion) presents with a large tendon defect between cut ends. Agents (/kg b.w., i.p., once time daily) (BPC 157 (dissolved in saline, with no carrier addition) (10 μg, 10 ng or 10 pg) or saline (5.0 ml)), were firstly applied at 30 min after surgery, the last application at 24 h before autopsy. Achilles functional index (AFI) was assessed once time daily. Biomechanical, microscopical and macroscopical assessment was on day 1, 4, 7, 10 and 14. Controls generally have severely compromised healing. In comparison, pentadecapeptide BPC 157 fully improves recovery: (i) biomechanically, increased load of failure, load of failure per area and Youngs modulus of elasticity; (ii) functionally, significantly higher AFI‐values; (iii) microscopically, more mononuclears and less granulocytes, superior formation of fibroblasts, reticulin and collagen; (iv) macroscopically, smaller size and depth of tendon defect, and subsequently the reestablishment of full tendon integrity. Likewise, unlike TGF‐β, pentadecapeptide BPC 157, presenting with no effect on the growth of cultured cell of its own, consistently opposed 4‐hydroxynonenal (HNE), a negative modulator of the growth. HNE‐effect is opposed in both combinations: BPC 157 + HNE (HNE growth inhibiting effect reversed into growth stimulation of cultured tendocytes) and HNE + BPC 157(abolished inhibiting activity of the aldehyde), both in the presence of serum and serum deprived conditions. In conclusion, these findings, particularly. Achilles tendon transection fully recovered in rats, peptide stability suitable delivery, usefully favor gastric pentadecapeptide BPC 157 in future Achilles tendon therapy.
European Journal of Pharmacology | 1986
Predrag Sikiric; Juraj Geber; Dragutin Ivanović; Veljko Gjuriš; Milica Tućan-Foretić; Stjepan Mise; Branimir Cvitanović; Ivo Rotkvic
Gastric lesions were provoked in all rats that had received intraperitoneally a single dose of the dopamine antagonists haloperidol, metoclopramide or domperidone 24 h before. Dose-dependence was demonstrated for haloperidol. This drug induced gastric lesions as early as 90 min after its application. The ulcerogenic effect of haloperidol was completely prevented or markedly reduced by simultaneous applications of dopamine agonists bromocriptine or L-dopa. We conclude that the model of gastric lesions induced by dopamine antagonists could be successfully applied in further investigations of the role of dopamine in the pathogenesis of ulcer disease.
Digestive Diseases and Sciences | 1997
Predrag Sikiric; Darko Mikus; Sven Seiwerth; Zeljko Grabarevic; J Peric; Paško Konjevoda; Darko Perovic; Ljubica Jurina; Stipislav Jadrijević; Nikola Jelovac; Pavao Miklić; Gojko Buljat; Rudolf Rucman; Marijan Petek; Vjekoslav Jagić; Branko Turkovic; Ivo Rotkvic; Stjepan Mise; Ivan Zoricic; Miro Hanzevacki; Jadranka Separovic; Miroslav Gjurasin; Anton Marovic
A superior effectiveness in various lesionassays was noted for the novel pentadecapeptide BPC 157,originated from human gastric juice protein (BPC) andclaimed to be a cytoprotective agent. From this viewpoint, as a previously untreatedexperimental improvement to create an acid-freeenvironmental for cytoprotection studies, totalgastrectomy was done 24 hr before the ulcerogenicprocedure. In the absence of stomach and gastric acid, the damagingeffects of cysteamine (400 mg/kg subcutaneously, death24 hr thereafter), to date thought to be an acid-relatedduodenal ulcerogen, and the BPC 157 cytoprotective effect (10 mug or 10 ng/kg intraperitoneally)were further challenged. BPC 157 was compared withreference agents [cimetidine (50), ranitidine (10),omeprazole (10), bromocriptine (10) and atropine (10) (mg/kg intraperitoneally, 1 hr beforecysteamine] known to be also cytoprotective. In naiverats, with intact stomach, all of them showed a strongbeneficial effect. Interestingly, in gastrectomizedanimals, the application of BPC 157 or the referenceagents before cysteamine significantly prevented theotherwise severe duodenal lesion development noted inthe control gastrectomized cysteamine rats. In groups without cysteamine, no lesions were noted(laparotomy, gastrectomy only, 24 or 48 hr postsurgicalperiod), nor was lesion potentiation seen incysteamine-treated laparotomized animals. In summary,these findings -- equal damaging effect ofcysteamine and equal protection of pentadecapeptide BPC157 and reference agents in gastrectomized and rats withintact stomach -- seem to be particularly relevantfor a cytoprotective viewpoint. Without a stomach,the cysteamine damaging effect was convincingly definedas an essential gastric acid-independent injury(analogous to ethanol gastric lesions). Likewise, a high “cytoprotective capacity,”apparently acid independent, common for all testedagents (novel pentadecapeptide BPC 157, cimetidine,ranitidine, omeprazole and atropine) could be clearlystressed.
Biological Psychiatry | 1998
Nikola Jelovac; Predrag Sikiric; Rudolf Rucman; Marijan Petek; Darko Perovic; Paško Konjevoda; Anton Marovic; Sven Seiwerth; eljko Grabarević; Jagoda Sumajstorčić; Goran Dodig; J Peric
BACKGROUND A novel gastric pentadecapeptide, BPC 157, has been shown to attenuate different lesions (i.e., gastrointestinal tract, liver, pancreas, somatosensory neurons). This suggests an interaction with the dopamine system. When used alone, BPC 157 does not affect gross behavior or induce stereotypy. METHODS We first investigated the effect of pentadecapeptide BPC 157 on stereotypy and acoustic startle response in rats, given as either a prophylactic (10 micrograms/kg i.p.) or therapeutic (10 ng/kg i.p.) regimen, with the dopamine indirect agonist amphetamine (10 mg/kg i.p.). RESULTS There was a marked attenuation of stereotypic behavior and acoustic startle response. When the medication was given at the time of maximum amphetamine-induced excitability, there was a reversal of this behavior. A further focus was on the effect of this pentadecapeptide on increased climbing behavior in mice pretreated with the dopamine antagonist haloperidol (5.0 mg/kg i.p.), and subsequently treated with amphetamine (20 mg/kg i.p. challenge 1, 2, 4, and 10 days after haloperidol pretreatment). This protocol is usually used for the study of behavioral supersensitivity to the amphetamine stimulating effect. CONCLUSIONS An almost complete reversal was noted when pentadecapeptide was coadministered with haloperidol. Together, these data provide compelling evidence for the interaction of pentadecapeptide BPC 157 with the dopamine system.
European Journal of Pharmacology | 1999
Nikola Jelovac; Predrag Sikiric; Rudolf Rucman; Marijan Petek; Anton Marovic; Darko Perovic; Sven Seiwerth; Stjepan Mise; Branko Turkovic; Goran Dodig; Pavle Miklic; Gojko Buljat; Ingrid Prkačin
A gastric pentadecapeptide, BPC 157, with the amino acid sequence, Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val, MW 1419, known to have a variety of protective effects in gastrointestinal tract and other organs, was recently shown to particularly affect dopamine systems. For instance, it blocks the stereotypy produced acutely by amphetamine in rats, and the development of haloperidol-induced supersensitivity to amphetamine in mice. Consequently, whether pentadecapeptide BPC 157, that by itself has no cataleptogenic effect in normal animals, may attenuate the immediate effects of neuroleptics application, particularly catalepsy, was the focus of the present report. Prominent catalepsy, otherwise consistently seen in the mice treated with haloperidol (0.625, 1.25, 2.5, 5.0 and 10.0 mg/kg b.w., i.p.) and fluphenazine (0.3125, 0.625, 1.25, 2.5 and 5.0 mg/kg b.w., i.p.) after 1.5, 3, 4.5, 6 and 7.5 h following administration, was markedly attenuated when pentadecapeptide BPC 157 (10 microg or 10 ng/kg b.w., i.p.) was coadministered with the neuroleptic. The number of cataleptic mice was markedly lower throughout most of the experimental period. Moreover, on challenge with lower doses of neuroleptics, catalepsy appearance was postponed and the mice, otherwise cataleptic since the earliest period, became cataleptic later, not before 3 or 4.5 h after neuroleptic administration, especially if protected with higher pentadecapeptide dose. Besides catalepsy, coadministration of the pentadecapeptide BPC 157, given in the above mentioned doses, reduced not only catalepsy but somatosensory disorientation (for 7.5 h after administration of a neuroleptic, assessed at intervals of 1.5 h, by a simple scoring system [0-5]) in haloperidol- or fluphenazine-challenged mice as it did in mice treated with sulpiride (20, 40, 80 and 160 mg/kg b.w., i.p.) or with clozapine (25, 50 and 100 mg/kg b.w., i.p.), in which case catalepsy was absent. In other experiments, considering the gastric origin of this pentadecapeptide, the focus was shifted to the evidence that a dose of haloperidol, cataleptogenic due to dopamine receptors blockade, induces gastric ulcers in rats. Coadministration of pentadecapeptide BPC 157 (10 microg, 10 ng, 1.0 ng, 100 pg/kg b.w., i.p.) to rats completely inhibited the lesions otherwise regularly evident 24 h after haloperidol (5.0 mg/kg b.w., i.p.) in control rats (18 of 20 rats had gastric lesions). This activity accompanied the antagonism of the haloperidol catalepsy in rats (assessed at 60-min intervals from I to 5 h after haloperidol), when 10-microg- or 10-ng regimens were given (lower doses could not influence catalepsy). Together, these findings indicate that pentadecapeptide BPC 157 fully interacts with the dopamine system, both centrally and peripherally, or at least, that BPC 157 interferes with some steps involved in catalepsy and/or ulcer formation.