Marko Duvnjak

The beneficial effect of BPC 157, a 15 amino acid peptide BPC fragment, on gastric and duodenal lesions induced by restraint stress, cysteamine and 96% ethanol in rats. A comparative study with H2 receptor antagonists, dopamine promotors and gut peptides

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.

Overview and developments in noninvasive diagnosis of nonalcoholic fatty liver disease

High prevalence of non-alcoholic fatty liver disease (NAFLD) and very diverse outcomes that are related to disease form and severity at presentation have made the search for noninvasive diagnostic tools in NAFLD one of the areas with most intense development in hepatology today. Various methods have been investigated in the recent years, including imaging methods like ultrasound and magnetic resonance imaging, different forms of liver stiffness measurement, various biomarkers of necroinflammatory processes (acute phase reactants, cytokines, markers of apoptosis), hyaluronic acid and other biomarkers of liver fibrosis. Multicomponent tests, scoring systems and diagnostic panels were also developed with the purposes of differentiating non-alcoholic steatohepatitis from simple steatosis or discriminating between various fibrosis stages. In all of the cases, performance of noninvasive methods was compared with liver biopsy, which is still considered to be a gold standard in diagnosis, but is by itself far from a perfect comparative measure. We present here the overview of the published data on various noninvasive diagnostic tools, some of which appear to be very promising, and we address as well some of still unresolved issues in this interesting field.

Hepatoprotective effect of BPC 157, A 15-aminoacid peptide, on liver lesions induced by either restraint stress or bile duct and hepatic artery ligation or CCl4 administration. A comparative study with dopamine agonists and somatostatin

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.

The influence of dopamine agonists and antagonists on indomethacin lesions in stomach and small intestine in rats

Dopamine agents (saline in control groups) were coadministered with indomethacin by either single or repeated application. The ulcerogenic effect (erosions and/or ulcers) of repeated given indomethacin on gastric mucosa differed clearly from that on intestinal mucosa. The effect on intestinal mucosa was markedly greater than after a single dose. The effects of dopamine agents appeared to be more consistent. Domperidone and haloperidol, given as single or repeated doses, strongly aggravated both the gastric and intestinal lesions. Bromocriptine and amantadine had a protective effect. The adverse effects of both dopamine antagonists (increased after repeated administration) were strongly inhibited by the simultaneous administration of either bromocriptine or amantadine. The involvement of the dopamine system (central or peripheral) in the mechanisms that maintain gastric (probably related to cytoprotection also) and intestinal mucosa integrity is therefore suggested.

Dopamine agonists prevent duodenal ulcer relapse. A comparative study with famotidine and cimetidine.

The present study investigated both the healing rate (after four weeks) and the relapse rate (during six months) following treatment with the dopamine-like drugs bromocriptine (2.5 mg twice daily), amantadine (100 mg nocte), or with the H2 blockers cimetidine (800 mg nocte), and famotidine (40 mg nocte) in 124 patients with endoscopically proven duodenal ulcer (DU). The ulcer was completely healed in 27 (amantadine), 26 (bromocriptine), 23 (cimetidine), and in 24 (famotidine) patients. Relapse was noted in 34.7% (cimetidine) and 25% (famotidine) versus 11.7% (amantadine) and 7.7% (bromocriptine) DU patients. No significant difference was found in initial healing rates. However, the relapse rate in the cimetidine-treated group was significantly higher than in all the other test groups. Additional comparisons between all the treatment categories showed a significantly lower relapse rate with the dopamine-like agents. These important new results indicate that dopamine-like compounds are equally effective as H2 blockers in inducing DU healing and may offer a promising advantage over H2 blockers concerning their efficacy in preventing ulcer relapse in DU patients.

Influence of the Degree of Liver Failure on Portal Blood Flow in Patients with Liver Cirrhosis

Portal vein haemodynamics as demonstrated by the pulsed Doppler system were studied in 37 patients with cirrhosis who had been classified in three groups (A, B, and C) in accordance with the degree of liver failure. Maximal inner diameter of the portal vein was significantly lower in patients who were considered to be in good condition (group A) than in patients with moderate and severe liver failure (group B and group C) (p less than 0.001). A significant difference was also found between group A and group B and between group A and group C with regard to the portal blood velocity and portal blood flow (p less than 0.001). In accordance with the presence and size of the oesophageal varices, in patients with large varices the portal blood velocity and portal blood flow were significantly lower than in patients without varices (p less than 0.001), whereas maximal inner portal vein diameter was significantly higher (p less than 0.001). This study demonstrated that in patients with cirrhosis circulatory alterations in the portal vascular bed may be, at least in part, an indicator of the stage of liver disease.

The effect of pentadecapeptide BPC 157 on inflammatory, non-inflammatory, direct and indirect pain and capsaicin neurotoxicity

The anti-nociceptive effects of a newly synthesized pentadecapeptide coded BPC 157 (an essential fragment of new organoprotective gastric juice peptide BPC) was evaluated in comparison with aspirin and morphine reference standards, in various experimental models of indirect/direct nociception and neurotoxicity: writhing (acetic acid/magnesium sulphate), tail pinching, hot-plate, and capsaicin application. BPC 157 administered either in the ng or μg per kg range, intraperitoneally, significantly reduced the reactions in the writhing (inflammatory and non-inflammatory, prostaglandin-dependent and independent) and tail pinching tests. In the hot-plate test, unlike morphine, BPC 157 had no effect on normal animals. However, when given to capsaicin treated rats, BPC 157 strongly reduced capsaicin-allodynia, either given as pretreatment or once daily for 14 days after the capsaicin injection. This reduction in capsaicin’s effect could not be obtained when BPC 157 was applied in the presence of established capsaicin-somatosensory neuron degeneration (application only on the 14th day after capsaicin), so it is possible that the effects of BPC 157 could be related specifically to the integrity of capsaicin-sensitive somatosensory neurons and their protection (e.g. primary afferent neurons having small-diameter somata and unmyelinated (C-) or thinly myelinated (A6-) fibres).

Hepatitis C virus, insulin resistance, and steatosis

Hepatitis C virus (HCV) is one of the main causes of liver disease worldwide. Liver steatosis is a common finding in many hepatic and extrahepatic disorders, the most common being metabolic syndrome (MS). Over time, it has been shown that the frequent coexistence of these two conditions is not coincidental, since many epidemiological, clinical, and experimental studies have indicated HCV to be strongly associated with liver steatosis and numerous metabolic derangements. Here, we present an overview of publications that provide clinical evidence of the metabolic effects of HCV and summarize the available data on the pathogenetic mechanisms of this association. It has been shown that HCV infection can induce insulin resistance (IR) in the liver and peripheral tissues through multiple mechanisms. Substantial research has suggested that HCV interferes with insulin signaling both directly and indirectly, inducing the production of several proinflammatory cytokines. HCV replication, assembly, and release from hepatocytes require close interactions with lipid droplets and host lipoproteins. This modulation of lipid metabolism in host cells can induce hepatic steatosis, which is more pronounced in patients with HCV genotype 3. The risk of steatosis depends on several viral factors (including genotype, viral load, and gene mutations) and host features (visceral obesity, type 2 diabetes mellitus, genetic predisposition, medication use, and alcohol consumption). HCV-related IR and steatosis have been shown to have a remarkable clinical impact on the prognosis of HCV infection and quality of life, due to their association with resistance to antiviral therapy, progression of hepatic fibrosis, and development of hepatocellular carcinoma. Finally, HCV-induced IR, oxidative stress, and changes in lipid and iron metabolism lead to glucose intolerance, arterial hypertension, hyperuricemia, and atherosclerosis, resulting in increased cardiovascular mortality.

Acid Inhibition and the Acid Rebound Effect

Acid secretion from gastric parietal cells is a result of a complex interaction between different stimulatory and inhibitory mediators. One of the most important mediators is gastrin, which stimulates gastric acid secretion from parietal cells mostly indirectly, by the release of histamine from enterochromaffin-like (ECL) cells. Therapy with antisecretory agents leads to hypergastrinemia, mucosal hyperplasia and increased ECL cell mass, which results in increase of gastric acid secretion capacity. This increased secretion capacity has been shown to manifest itself after antisecretory therapy withdrawal as rebound acid hypersecretion (RAH). Various studies have quantified acid hypersecretion after the cessation of therapy with H2 antagonists and proton-pump inhibitors (PPIs). While most of those studies had small patient numbers, the findings generally demonstrate that RAH after H2 antagonist therapy is of low magnitude, short duration, and has questionable clinical significance. On the contrary, acid hypersecretion after PPI therapy is more pronounced, lasts longer, and could possibly be the cause of acid-related symptoms. Potential for causing symptoms has recently been confirmed in two randomized placebo-controlled studies, and while we witness the increasing use of PPIs, RAH could become a proven cause of failure to withdraw therapy in a proportion of patients with reflux or dyspeptic symptoms.

A Model of Inflammatory Bowel Disease Induced by 2,4-Dinitrofluorobenzene in Previously Sensitized BALB-c Mice

The aim of this study was to develop a model of inflammatory bowel disease (IBD) induced by colonic application of 2,4-dinitrofluorobenzene in previously sensitized BALB-c mice. During the follow-up period of 30 days we observed ulcerations, haemorrhage, necrosis, and mononuclear infiltration in the colonic mucosa of previously sensitized (experimental) and, to a lesser extent, nonsensitized (control) animals. In addition, the animals in the experimental group developed adhesions, thickening of colonic segments, stenosis, and dilatation of the colon, and some animals also developed megacolon. Oedema, mononuclear infiltration, and superficial ulcerations were observed in the ileum of experimental animals and, to a lesser extent, in the control group. In addition, the animals in the experimental group developed extraintestinal changes in the liver and spleen (that is, pericholangitis and lymphofollicular proliferation). We suggest that this model of IBD may have some value for the study of early pathogenetic mechanisms of IBD and for developing new therapeutic modalities for this condition.