Władysław Bielański

Bio: Władysław Bielański is an academic researcher from Jagiellonian University Medical College. The author has contributed to research in topics: Helicobacter pylori & Gastrin. The author has an hindex of 28, co-authored 47 publications receiving 1654 citations.

Basal and postprandial plasma levels of PYY, ghrelin, cholecystokinin, gastrin and insulin in women with moderate and morbid obesity and metabolic syndrome.

Abstract: Metabolic syndrome (MS), defined as central obesity, hyperinsulinemia, insulin resistance, hypertension, dyslipidemia and glucose intolerance, has been associated with inflammatory biomarkers and cardiovascular diseases. This study was carried out on three groups of women; lean controls, moderately obese with MS (OB-MS) and morbidly obese with MS (MOB-MS). The main objectives were: 1. to analyze the plasma levels of total and acylated ghrelin, peptide YY(3-36) (PYY(3-36)), cholecystokinin (CCK), gastrin and insulin levels under basal conditions and in response to a standard mixed meal, and 2. to elucidate the relationship between the plasma levels of these gut peptides and metabolic syndrome parameters. Plasma levels of the gut hormones were measured by radioimmunoassays at time 0 just before the meal and at 30, 60 and 120 min after a meal ingestion. Traditional lipid profile and high-sensitivity C reactive protein (hs-CRP), the strongest biomarker of inflammation were also determined in OB-MS and MOB-MS. When compared to OB-MS, MOB-MS exhibited much higher anthropometric parameters such as waist circumference, higher fat mass and higher plasma levels of low density lipoprotein-cholesterol (LDL-C) and hs-CRP. Both these obese groups revealed significantly higher values of body mass index (BMI), fat mass, total cholesterol (TC), LDL-C, fasting glucose, fasting insulin, insulin resistance (IR) calculated from homeostatic model assessment (HOMA) and hs-CRP compared to the values recorded in lean subjects. Fasting PYY(3-36) level was lower, while fasting acylated ghrelin was higher in MOB-MS than in OB-MS. Plasma total and acylated ghrelin levels were significantly lower in OB-MS compared to lean women. In MOB-MS women the fasting PYY(3-36) levels were lower compared to lean controls and OB-MS, whilst postprandially in both OB-MS and MOB-MS, it was much lower than in lean women. The fasting plasma levels of total and acylated ghrelin and their postprandial decrease were significantly smaller in both obese groups compared to lean subjects. Plasma hs-CRP levels correlated positively with BMI, waist circumference, fat mass, fasting glucose, HOMA IR and fasting active ghrelin, whilst it negatively correlated with plasma fasting and total ghrelin. Moreover, plasma fasting acylated ghrelin correlated positively with fat mass. Fasting total ghrelin correlated positively with BMI, HDL-C and negatively with HOMA IR. We conclude that MS features of obesity are closely related to fasting and postprandial alterations of concentrations of PYY(3-36), CCK and ghrelin, suggesting that determination of gut hormones controlling food intake might be considered as a valuable tool to assess the progression of MS to comorbidities of obesity.

The effects of long-term melatonin treatment on plasma liver enzymes levels and plasma concentrations of lipids and melatonin in patients with nonalcoholic steatohepatitis: a pilot study

Abstract: The present study represents the follow-up of our initial observations designed to investigate whether in patients with nonalcoholic steatohepatitis (NASH) the beneficial effect of 12-week course of melatonin (MT) on liver enzymes could be maintained with prolonged period of treatment and to analyze whether biochemical treatment responses could be sustainable after melatonin discontinuation. Forty two patients with histologically proven NASH (30 treated with melatonin 2x5 mg daily, 12 controls receiving placebo) enrolled to our previous 3-month study agreed to take part of subsequent 12 weeks treatment followed by 12-week follow-up period. Enrolled patients had biochemical determinations every six weeks during the melatonin treatment period and again after 12 weeks of follow-up. Significant reduction in median alanine aminotransferase (ALT) levels between baseline and week 18, week 24 and follow-up was observed in both MT-treated and control group: 43% and 31%, 42% and 33%, 32% and 31%. Aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (GGT) levels decrease significantly only in MT-treated group. In MT-treated group mean percentage change in AST level below baseline at week 18, at week 24 and at follow-up was 45%, 33% (p<0.05) and 8% (ns), respectively. The evolution of GGT levels was as follows: the mean percentage reduction in GGT below baseline level at week 18, 24 and follow-up was: 48%, 52% and 38% (p<0.05), respectively. In both MT-treated and control group plasma cholesterol, triglicerydes and glucose concentrations as well as plasma alkaline phosphatase persisted within normal values during the prolonged study period. Plasma concentration of melatonin (pg/ml) in MT-treated group averaged 7.5±3.5 at baseline and increased to 52.5±17.5 at 24th week. The results of our study demonstrating beneficial effect of melatonin on liver enzymes in patients with NASH would seem to encourage further controlled trials of melatonin given over a longer period of time with liver histology as end point.

Helicobacter pylori associated gastric pathology.

Abstract: Helicobacter pylori (HP), undoubtedly, the most common world-wide infection plays an important role in pathogenesis of peptic ulcer. Proof for a causal role for HP in peptic ulcer rests in two major points; 1) the majority of ulcer patients are HP infected and the prevalence of this infection for both gastric ulcer (GU) and duodenal ulcer (DU) is much higher than for gender- and age-adjusted controls and 2) the cure of HP infection dramatically reduces ulcer recurrence. Conclusions regarding the mechanisms by which HP induces peptic ulcer are restricted mainly to studies observing the consequences of its eradication by antibiotics combined with gastric inhibitors or bismuth agents. Several specific virulence factors such as cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA) as well as other noxious substances including ammonia, lipopolysaccharide (endotoxin), platelet activating factor (PAF), nitric oxide (NO) and others have been implicated in gastritis and were found to be significantly more frequent in gastric cancer than in gender- and age-matched controls, especially in younger generation. Chronic inflammation, atrophic gastritis, intestinal metaplasia, impaired defense mechanisms combined with hypergastrinemia, deficiency of vitamin C in the stomach , excessive oxygen metabolites and epithelial cell proliferation have been associated with gastric cancer. This multi-step pathway originally proposed by Correa and his colleagues, long before the HP was discovered in the stomach, leads to cancer but may be reversed by eradication of HP. This is, however, a controversial issue because gastric atrophy and intestinal metaplasia may be also caused by other factors such as bile reflux, dietary irritants, and autoimmunity. The implication of HP in MALT-lymphoma is based on the observations that eradication of HP in early stage of low-grade of this tumor leads to complete remission. The significance of HP in non-ulcer dyspepsia remains questionable and requires further studies.

The pilot study of 3-month course of melatonin treatment of patients with nonalcoholic steatohepatitis: effect on plasma levels of liver enzymes, lipids and melatonin.

Abstract: The mechanism by which nonalcoholic fatty liver disease (NAFLD) progresses into nonalcoholic steatohepatitis (NASH) is unknown, however, the major process is oxidative stress with increased production of reactive oxygen species and excessive inflammatory cytokine generation. To date, there are no effective treatments for NASH and the published data with treatment using antioxidants are not satisfactory. Melatonin (MT), the potent endogenous antioxidant secreted in circadian rhythm by pinealocytes and in large amounts in the digestive system, was reported to improve oxidative status and to exert beneficial effects in NASH pathology in experimental animals, but no study attempted to determine the possible effectiveness of MT in humans with NASH. In this study, 42 patients (12 placebo controls and 30 MT-treated) with histological evidence (liver biopsy) of NASH and no history of alcohol abuse, were included. The treatment group took melatonin (2x5 mg/daily orally), while controls were treated with placebo. At baseline no significant differences between the groups were found for age, body mass index (BMI) as well as for plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP), and concentrations of cholesterol, triglycerides (TG), glucose and MT. During the study period plasma ALT level and cholesterol concentration decreased significantly in both MT-treated and control groups, however AST and GGT levels decreased significantly only in MT-treated groups. Median value of AST level at baseline was 76.5 (64.2-114.2) IU/L and its percentage decrease at 4, 8 and 12 week was 20, 36 and 38%, resp. Baseline GGT median level was 113 (75.7-210.7) IU/L and its mean percentage decrease at week 4, 8 and 12 was 46, 48 and 47%, resp. Plasma ALP levels did not change significantly during MT treatment. Median value of plasma concentrations of MT (pg/mL) in MT-treated group rose from 7.5 (5.0-14.25) at baseline to 35.5(18.8-110.0), 43.5(17.0-102.5) and 49.5(18.0-99.5) at the end of 4, 8 and 12 week of treatment, respectively. Plasma levels of TG and glucose as well as BMI in controls and MT-treated patients were not significantly different from baseline. This study demonstrates for the first time in humans that three months treatment with MT significantly improves plasma liver enzymes in patients with NASH without causing any side-effect. Plasma MT levels during the whole period of MT treatment persisted above that at baseline. Our findings show that treatment with MT significantly improves plasma liver enzymes in NASH patients, but larger cohort trials and longer treatment with MT are required before this indole could be included into the spectrum of the NASH treatment.

BRIEF COMMUNICATION ARISING: Gut hormone PYY3-36 physiologically inhibits food intake

Abstract: Food intake is regulated by the hypothalamus, including the melanocortin and neuropeptide Y (NPY) systems in the arcuate nucleus. The NPY Y2 receptor (Y2R), a putative inhibitory presynaptic receptor, is highly expressed on NPY neurons in the arcuate nucleus, which is accessible to peripheral hormones. Peptide YY3-36 (PYY3-36), a Y2R agonist, is released from the gastrointestinal tract postprandially in proportion to the calorie content of a meal. Here we show that peripheral injection of PYY3-36 in rats inhibits food intake and reduces weight gain. PYY3-36 also inhibits food intake in mice but not in Y2r-null mice, which suggests that the anorectic effect requires the Y2R. Peripheral administration of PYY3-36 increases c-Fos immunoreactivity in the arcuate nucleus and decreases hypothalamic Npy messenger RNA. Intra-arcuate injection of PYY3-36 inhibits food intake. PYY3-36 also inhibits electrical activity of NPY nerve terminals, thus activating adjacent pro-opiomelanocortin (POMC) neurons. In humans, infusion of normal postprandial concentrations of PYY3-36 significantly decreases appetite and reduces food intake by 33% over 24 h. Thus, postprandial elevation of PYY3-36 may act through the arcuate nucleus Y2R to inhibit feeding in a gut–hypothalamic pathway.

Molecular Mechanisms of Depression: Perspectives on New Treatment Strategies

Abstract: Depression is a multicausal disorder and has been associated with the risk to develop cancer, dementia, diabetes, epilepsy and stroke. As a metabolic disorder depression has been associated with obesity, diabetes, insulin sensitivity, neuropeptide Y, glucose regulation, poor glycemic control, glucagone-like peptide-1, cholezystokinin, ghrelin, leptin, the endocannabinoid system, insulin-like growth factor and gastrin-releasing peptide. As a cardiovascular disease a close relationship exists between depression and blood pressure, heart rate, norepinephrine, sympathetic tone, vascular resistance, blood viscosity, plasma volume, intima thickness and atherosclerosis. Additionally blood coagulation, fibrinolysis, D-dimers, plasminogen activator inhibitor-1 protein, platelet activation, VEGF, plasma nitric oxide and its synthase are changed in depressed patients. As an endocrinological and stress disorder depression has been connected with the concentration of free T4, TSH, CRH, arginine vasopressin, corticotrophin, corticosteroid release and ACTH. Depression as an inflammatory disorder is mediated by pro-inflammatory cytokines, interleukin-1, interleukin-6, TNF-alpha, soluble interleukin-2 receptors, interferon-alpha, interleukin 8, interleukin-10, hs-CRP, acute phase proteins, haptoglobin, toll like receptor 4, interleukin-1beta, mammalian target of rapamycin pathway, substance P, cyclooxygenase-2, prostaglandin-E2, lipid peroxidation levels and acid sphingomyelinase. Nutritional factors might influence depression risk, i.e. the consumption of folate, omega-3 fatty acids, monounsaturated fatty acids, olive oil, fish, fruits, vegetables, nuts, legumes, vitamin B6 and vitamin B12. The neurodegenerative hypothesis of depression explains decreased hippocampal volumes in depressed patients and changes of neurotrophic support by BDNF, erythropoietin, GDNF, FGF-2, NT3, NGF and growth hormone. In this context, a fast neuroprotective and antidepressant effect has also been observed by ketamine, which acts via the glutamatergic system. Hence, GABA, AMPA, EAAT, NMDA- and metabotropic glutamate receptors (mGluR1 to mGluR8) have gained interest in depression recently. Alternative, causative or also easy available treatment strategies beyond serotonin and noradrenaline reuptake inhibition might be a major topic of future psychiatric care. In this review, an attempt is made to overview concepts of the disease and search for perspectives on antidepressant treatment strategies beyond approved medications.

Nitric oxide and superoxide in inflammation and immune regulation.

Abstract: Nitric oxide (NO) and reactive oxygen species exert multiple modulating effects on inflammation and play a key role in the regulation of immune responses. They affect virtually every step of the development of inflammation. Low concentrations of nitric oxide produced by constitutive and neuronal nitric oxide synthases inhibit adhesion molecule expression, cytokine and chemokine synthesis and leukocyte adhesion and transmigration. Large amounts of NO, generated primarily by iNOS can be toxic and pro-inflammatory. Actions of nitric oxide are however not dependent primarily on the enzymatic source, but rather on the cellular context, NO concentration (dependent on the distance from NO source) and initial priming of immune cells. These observations may explain difficulties in determining the exact role of NO in Th1 and Th2 lymphocyte balance in normal immune responses and in allergic disease. Similarly superoxide anion produced by NAD(P)H oxidases present in all cell types participating in inflammation (leukocytes, endothelial and other vascular cells etc) may lead to toxic effects, when produced at high levels during oxidative burst, but may also modulate inflammation in a far more discrete way, when continuously produced at low levels by NOXs (non-phagocytic oxidases). The effects of both nitric oxide and superoxide in immune regulation are exerted through multiple mechanisms, which include interaction with cell signalling systems like cGMP, cAMP, G-protein, JAK/STAT or MAPK dependent signal transduction pathways. They may also lead to modification of transcription factors activity and in this way modulate the expression of multiple other mediators of inflammation. Moreover genetic polymorphisms exist within genes encoding enzymes producing both NO and superoxide. The potential role of these polymorphisms in inflammation and susceptibility to infection is discussed. Along with studies showing increasing role of NO and free radicals in mediating inflammatory responses drugs which interfere with these systems are being introduced in the treatment of inflammation. These include statins, angiotensin receptor blockers, NAD(P)H oxidase inhibitors, NO-aspirin and others. In conclusion in this mini-review we discuss the mechanisms of nitric oxide and superoxide dependent modulation of inflammatory reactions in experimental animals and humans. We also discuss potential roles of nitric oxide as a mediator of allergic inflammation.

Chronic inflammation and cancer.

Abstract: A substantial body of evidence supports the conclusion that chronic inflammation can predispose an individual to cancer, as demonstrated by the association between chronic inflammatory bowel diseases and the increased risk of colon carcinoma. Chronic inflammation is caused by a variety of factors, including bacterial, viral, and parasitic infections, chemical irritants, and nondigestible particles. The longer the inflammation persists, the higher the risk of associated carcinogenesis. This review describes some of the underlying causes of the association between chronic inflammation and cancer. Inflammatory mediators contribute to neoplasia by inducing proneoplastic mutations, adaptive responses, resistance to apoptosis, and environmental changes such as stimulation of angiogenesis. All these changes confer a survival advantage to a susceptible cell. In this article, we discuss the contribution of reactive oxygen and nitrogen intermediates, prostaglandins, and inflammatory cytokines to carcinogenesis. A thorough understanding of the molecular basis of inflammation-associated neoplasia and progression can lead to novel approaches to the prevention and treatment of cancer.

Melatonin: an ancient molecule that makes oxygen metabolically tolerable.

Abstract: Melatonin is remarkably functionally diverse with actions as a free radical scavenger and antioxidant, circadian rhythm regulator, anti-inflammatory and immunoregulating molecule, and as an oncostatic agent. We hypothesize that the initial and primary function of melatonin in photosynthetic cyanobacteria, which appeared on Earth 3.5-3.2 billion years ago, was as an antioxidant. The evolution of melatonin as an antioxidant by this organism was necessary as photosynthesis is associated with the generation of toxic-free radicals. The other secondary functions of melatonin came about much later in evolution. We also surmise that mitochondria and chloroplasts may be primary sites of melatonin synthesis in all eukaryotic cells that possess these organelles. This prediction is made on the basis that mitochondria and chloroplasts of eukaryotes developed from purple nonsulfur bacteria (which also produce melatonin) and cyanobacteria when they were engulfed by early eukaryotes. Thus, we speculate that the melatonin-synthesizing actions of the engulfed bacteria were retained when these organelles became mitochondria and chloroplasts, respectively. That mitochondria are likely sites of melatonin formation is supported by the observation that this organelle contains high levels of melatonin that are not impacted by blood melatonin concentrations. Melatonin has a remarkable array of means by which it thwarts oxidative damage. It, as well as its metabolites, is differentially effective in scavenging a variety of reactive oxygen and reactive nitrogen species. Moreover, melatonin and its metabolites modulate a large number of antioxidative and pro-oxidative enzymes, leading to a reduction in oxidative damage. The actions of melatonin on radical metabolizing/producing enzymes may be mediated by the Keap1-Nrf2-ARE pathway. Beyond its direct free radical scavenging and indirect antioxidant effects, melatonin has a variety of physiological and metabolic advantages that may enhance its ability to limit oxidative stress.