Biomedical subjects

S J Konturek

Publications and source records attributed to S J Konturek.

At least 19 recordsLinked to original sources

PubMed2006

Effect of ischemic preconditioning on pancreatic regeneration and pancreatic expression of vascular endothelial growth factor and platelet-derived growth factor-A in ischemia/reperfusion-induced pancreatitis.

UNLABELLED: Ischemic preconditioning has been shown to protect several organs from ischemia/reperfusion-induced injury. In the pancreas, protective effect of ischemic preconditioning has been shown against pancreatitis evoked by ischemia/reperfusion, as well as by caerulein. However, the effect of ischemic preconditioning on the course of acute pancreatic is unclear. The aim of our study was to evaluate the influence of ischemic preconditioning on pancreatic regeneration and pancreatic presence of platelet-derived growth factor-A (PDGF-A) and vascular endothelial growth factor (VEGF) in the course of ischemia/reperfusion-induced pancreatitis. METHODS: In male Wistar rats, ischemic preconditioning of the pancreas was performed by short-term clamping of celiac artery (twice for 5 min with 5 min interval). Acute pancreatitis was induced by clamping of inferior splenic artery for 30 min followed by reperfusion. Rats were sacrificed 1, 5, 12 h or 1, 2, 3, 5, 7, 9 and 21 days after the start of reperfusion. Severity of acute pancreatitis and pancreatic regeneration were determined by biochemical and morphological examination, expression of growth factors was determined by immunohistochemical analysis. RESULTS: In ischemia/reperfusion-induced pancreatitis, the pancreatic damage reached the maximal range between the first and second day of reperfusion, and was followed by subsequent pancreatic regeneration. Ischemic preconditioning alone caused mild passing pancreatic damage and an increase in plasma concentration of pro-inflammatory interleukin-1 and anti-inflammatory interleukin-10. Ischemic preconditioning applied before ischemia/reperfusion-induced pancreatitis reduced morphological and biochemical signs of the pancreatitis-evoked pancreatic damage and accelerated pancreatic regeneration. This effect was associated with improvement of pancreatic blood flow. Ischemic preconditioning, ischemia/reperfusion-induced pancreatitis and their combination increased the presence of VEGF in acinar and islet cells, and immunostaining for PDGF-A in blood vessels. This effect was maximally pronounced after combination of ischemic preconditioning plus pancreatitis and occurred earlier than after pancreatitis alone. CONCLUSIONS: Ischemic preconditioning reduces pancreatic damage and accelerates pancreatic healing in the course of ischemia/reperfusion-induced pancreatitis. This effect is associated with the increase in plasma concentration of anti-inflammatory interleukin-10, improvement of pancreatic blood flow and alteration of pancreatic immunohistochemical expression of PDGF-A and VEGF.

Animals↗

PubMed2006

Napoleon Cybulski--Polish pioneer in developing of the device for measuring blood flow velocity.

Napoleon Cybulski (1854-1919) was the most prominent Polish physiologist who chaired the Department of Physiology at the Faculty of Medicine of Jagiellonian University between 1885 and 1919. One of his greatest achievements was the construction of a device for precise measurements of blood movement in the vessels - the photohemotachometer, which provided a better insight into the physiology and pathophysiology of the circulatory system. In the field of endocrinology Cybulski together with Szymonowicz, found out that adrenal extracts contain biologically active substances that elevate blood pressure. He was also a constructor of an extremely clever microcalorimeter to measure the quantity of heat produced during isolated muscle contraction. He applied, for the first time, condensator discharges to stimulate nerves and analyzed changes in the excitability of the muscles. Cybulski proved that the cause of the electrical excitability of tissue depends on the electrical energy and the time of its duration. Together with Beck, he performed the experiments on the sensory centers in the central nervous system by means of the observations of the electrical evoked potentials. They discovered the continuous electrical oscillations in the brain - the brain waves and recorded the negative electrical potentials in certain brain areas induced by sensory impulses coming from the periphery. Using this technique Beck and Cybulski localized various centers in the brain of dogs and Macaccus rhesus monkeys. The names of Beck and Cybulski were quoted in many publications on neurophysiology and electroencephalography. The present paper describes Napoleon Cybulski as a constructor of an original instrument for studying the movement of blood under various experimental conditions an emphasizes the contribution of this invention to the development of physiology.

Blood Circulation↗

PubMed2006

Helicobacter pylori inhibits expression of heat shock protein 70 (HSP70) in human epithelial cell line. Importance of Cag A protein.

Heat shock proteins (HSP) are crucial for the maintenance of cell integrity under normal cell growth and at pathophysiological conditions such as colonization of gastric mucosa by Helicobacter pylori (Hp). The effect of Hp on mRNA expression for HSP70 in the gastric epithelial cells in vitro has been little studied and remains inconclusive. In this study we attempted to determine the alterations in gene expression for HSP70 induced by two live strains of Hp in the epithelial MKN7 cells. The following Hp strains were employed; 1) Hp strain expressing cagA and vacA, and 2) cagA and vacA negative Hp strain without or with addiction of exogenous recombinant protein CagA. MKN7 cells were incubated in a standard medium RPMI 1640 supplemented with 10% fetal bovine serum at 37 degrees C with 5% CO2 and humidified atmosphere under basal condition or in a presence of Hp (1 x 10(9) CFU per dish) without or with the recombinant CagA (10 microg/ml of RPMI 1640 medium). After 3 h, 24 h and 48 h of incubation with Hp and in some experiments with the prolonged incubation time up to 72 h, the cells were harvested, the total cellular RNA was isolated and the expression of mRNA for HSP70 was determined by RT-PCR. The incubation of the MKN cells with CagA protein alone failed to affect significantly the expression of HSP70. In contrast, the strain Hp (cagA+, vacA+) inhibited in time-dependent manner the expression of mRNA for HSP70. When the MKN7 cells were coincubated with Hp (cagA+, vacA+) and exogenous CagA, the significant inhibition of the signal intensity for HSP70 mRNA was observed at 3 h and 24 h of incubation and these effects were followed by complete disappearance of the signal for HSP70 mRNA at 48 h. The incubation of MKN7 with Hp (cagA-, vacA-) also significantly attenuated the expression of HSP70 mRNA with the most pronounced inhibitory effect observed at 72 h of incubation with this Hp strain. Addition of the recombinant CagA to Hp (cagA-, vacA-) completely suppressed the expression of HSP70 at 48 h and 72 h after the end of incubation periods. We conclude that 1) both, Hp (cagA+, vacA+) and Hp (cagA-, vacA-) inhibit expression of HSP70 in MKN7 human gastric epithelial cells independently of the presence or absence of cagA gene, and that 2) recombinant CagA protein may exert biological activity in vitro via acceleration of inhibitory effect of Hp negative for Cag A and VacA on HSP70 expression in epithelial cells infected with this bacteria.

Antigens, Bacterial↗

PubMed2006

Influence of ghrelin on gastric and duodenal growth and expression of digestive enzymes in young mature rats.

UNLABELLED: Ghrelin, a nature ligand for the growth hormone secretagogue receptor (GHS-R), stimulates a release of growth hormone, prolactin and adrenocorticotropic hormone. Also, ghrelin increases food intake in adult rats and humans and exhibits gastroprotective effect against experimental ulcers induced by ethanol or stress. The aim of present study was to examine the influence of ghrelin administration on gastric and duodenal growth and expression of pepsin and enterokinase in young mature rats with intact or removed pituitary. METHODS: Two week after sham operation or hypophysectomy, eight week old Wistar male rats were treated with saline (control) or ghrelin (4, 8 or 16 nmol/kg/dose) i.p. twice a day for 4 days. Expression of pepsin in the stomach and enterokinase in the duodenum was evaluated by real-time PCR. RESULTS: In animals with intact pituitary, treatment with ghrelin increased food intake, body weight gain and serum level of growth hormone and insulin-like growth factor-1 (IGF-1). These effects were accompanied with stimulation of gastric and duodenal growth. It was recognized as the significant increase in gastric and duodenal weight and mucosal DNA synthesis. In both organs, ghrelin administered at the dose of 8 nmol/kg caused maximal growth-promoting effect. In contrast to these growth-promoting effects, administration of ghrelin reduced expression of mRNA for pepsin in the stomach and was without effect on expression of mRNA for enterokinase in the duodenum. Hypophysectomy alone lowered serum concentration of growth hormone under the detection limit and reduced serum level of IGF-1 by 90%. These effects were associated with reduction in daily food intake, body weight gain and gastroduodenal growth. In hypophysectomized rats, administration of ghrelin was without significant effect on food intake, body weight gain or growth of gastroduodenal mucosa. Also, serum concentration of growth hormone or IGF-1 was not affected by ghrelin administration in rats with removed pituitary. CONCLUSION: Administration of ghrelin stimulates gastric and duodenal growth in young mature rats with intact pituitary, but inhibits expression of mRNA for pepsin in the stomach. Growth hormone and insulin-like growth factor-1 play an essential role in growth-promoting effects of ghrelin in the stomach and duodenum.

Analysis of Variance↗

PubMed2006

Helicobacter pylori and its involvement in gastritis and peptic ulcer formation.

Modern gastroenterology started in early 19(th) century with the identification by W. Prout of the inorganic (hydrochloric) acid in the stomach and continued through 20(th) century with the discoveries by I.P. Pavlov of neuro-reflex stimulation of gastric secretion for which he was awarded first Nobel Prize in 1904. When concept of nervism or complete neural control of all digestive functions reached apogeum in Eastern Europe, on the other side of Europe (in United Kingdom), E. Edkins discovered in 1906 that a hormone, gastrin, may serve as chemical messenger in stimulation of gastric acid secretion, while L. Popielski revealed in 1916 that histamine is the most potent gastric secretagogue. K. Schwartz, without considering neural or hormonal nature of gastric secretory stimulation, enunciated in 1910 famous dictum; "no acid no ulcer"; and suggested gastrectomy as the best medication for excessive gastric acid secretion and peptic ulcer. In early 70s, J.W. Black, basing on earlier L. Popielski's histamine concept, identified histamine-H(2) receptors (H(2)-R) and obtained their antagonists, which were found very useful in the control of gastric acid secretion and ulcer therapy for which he was awarded in 1972 second Nobel Prize in gastrology. With discovery by G. Sachs in 1973 of proton pumps and their inhibitors (PPI), even more effective in gastric acid inhibition and ulcer therapy than H(2)-R antagonists, gastric surgery, namely gastrectomy, practiced since first gastric resection in 1881 by L. Rydygier, has been considered obsolete for ulcer treatment. Despite of the progress in gastric pharmacology, the ulcer disease remained essentially "undefeated" and showed periodic exacerbation and relapses. The discovery of spiral bacteria in the stomach in 1983 by B.J. Marshall and R.J. Warren, Australian, clinical researches, awarded in 2005 the Nobel Prize for the third time in gastrology, has been widely considered as a major breakthrough in pathophysiology of gastritis and peptic ulcer, which for the first time can be definitively cured by merely eradication of germ infecting stomach. This overview presents the mechanism of induction of gastritis and peptic ulcer by the H. pylori infection and describes accompanying changes in gastric acid and endocrine secretion as well as the effects of germ eradication on gastric secretory functions and gastroduodenal mucosal integrity.

Animals↗

PubMed2006

Gastric cancer and Helicobacter pylori infection.

The Nobel prize in Physiology and Medicine in 2005 was presented to Barry Marshall and Robin Warren for their discovery of Helicobacter pylori (Hp), but only the involvement of this germ in gastritis and peptic ulcer has been mentioned in the award sentence, while numerous epidemiological, clinical and experimental studies and reports emphasized the crucial role of Hp in pathogenesis of gastric cancer (GC). This review is based on the old concept proposed by P. Correa much before the discovery of spiral bacteria in the stomach, postulating the cascade of mucosal changes from acute/chronic gastritis into the atrophic gastritis with intestinal metaplasia and finally to dysplasia and GC. It is now widely accepted view that Hp infection is the major initiator of the inflammatory and atrophic changes in gastric mucosa accompanied by an over-expression of certain growth factors such as gastrin as well as of cyclooxygenase-2 (COX-2) and anti-apoptotic proteins including survivin and B-cl(2), leading to proliferation of mutated atrophic cells, excessive angiogenesis, inhibition of apoptosis and formation of gastric tumour. All the morphological and biochemical changes associated with the transformation of mucosal cells into the cancer cells can be traced in excellent experimental model of gastric cancerogenesis induced by infection of Hp in Mongolian gerbils. Since the eradication therapy was proved in several prospective clinical trials to greatly reduce the incidence of GC and this was confirmed on the gerbil model of Hp-induced GC, it has been postulated; a) that Hp is the major causal factor in pathogenesis of GC and b) that the only rational approach in attempt to reduce the occurrence of GC is the global eradication of Hp.

Animals↗

PubMed2006

Interaction of nonsteroidal anti-inflammatory drugs (NSAID) with Helicobacter pylori in the stomach of humans and experimental animals.

Helicobacter pylori (H. pylori) and non-steroidal anti-inflammatory drugs (NSAID) are major pathogenic factors in peptic ulcer disease but whether these two factors exert synergistic or antagonistic action on the gastric mucosa has been a subject of controversy. The classic concept states that there is an increased ulcer occurrence and bleeding in patients with both H. pylori infection and NSAID use. However, the question whether the H. pylori eradication therapy in NSAID users reduces the occurrence of peptic ulcer has not been fully addressed. Studies on secondary prevention of NSAID-associated ulcers in H. pylori patients have indicated that H. pylori eradication results in impaired ulcer healing with an effect on the rate of peptic ulcer occurrence. On the other hand, the treatment of H. pylori in patients with no prior history of chronic NSAID therapy has been shown to decrease the risk of peptic ulcer. Studies in experimental animals revealed for instance, that the H. pylori infection augments the gastric mucosal damage induced by NSAID in Mongolian gerbils. In rats with preexisting chromic gastric ulcers, H. pylori infection attenuated significantly the aspirin-induced inhibition of ulcer healing and accompanying fall in the gastric blood flow at the margin of these ulcers, suggesting negative interaction between aspirin and H. pylori on ulcerogenesis. Accumulated evidence in humans and animals shows that both aspirin and H. pylori upregulate the expression of cyclooxygenase (COX)-2 both at mRNA and protein levels at the ulcer margin, but failed to influence significantly that of COX-1. It was, therefore, proposed that H. pylori may in fact, antagonize, aspirin-induced delay of ulcer healing due to suppression of acid secretion by the enhancement in PGE(2) possibly derived from COX-2 expression and activity and to the overexpression of growth factors such as TGF alpha and VEGF. The present review summarizes and further addresses the issue of the interaction between these two major ulcer risk factors determined in the stomach of humans and experimental animals.

Animals↗

PubMed2006

The relationship between the presence of Helicobacter pylori in the oral cavity and gastric in the stomach.

There are numerous studies suggesting that inflammation of the oral cavity caused by bacteria or fungi is accompanied by gastric inflammation. This is particularly relevant in patients using complete dentures. Since the presence of H. pylori in the oral cavity can be easily discovered by bacteria culture and that in the stomach by (13)C urea breath test (UBT) and histology of gastric endoscopic biopsy samples it is reasonably to state that the majority of the patients show the presence of bacterium in oral cavity and active gastric H. pylori infection. When comparing, however, the bacteria culture originating from the oral mucosa to those from the gastric mucosa, employing molecular biology examination, such as polymerase chain reaction (PCR), we found that the oral bacteria and those originating from stomach are completely different, suggesting that H. pylori may be present only transiently in oral cavity and does not play major role in gastric H. pylori infection. Thus, oral cavity does not serve as bacterial reservoir to infect gastric mucosa. Most important finding of our study is that patients with recognized inflammation in the oral cavity in the form of stomatitis prothetica hyperplasica both fibrosa as well as papillaris showed in nearly 100% gastric H. pylori infection, usually without the presence of the same bacterium in the oral cavity, suggesting that gastric H. pylori infection affects oral mucosa at distance by some, as yet, unknown mechanism.

Adult↗

PubMed2006

Helicobacter pylori infection in coronary artery disease.

The role of inflammation in the pathogenesis and progression of coronary artery disease (CAD) has been increasingly discussed, but still remains unclear. Inflammatory changes in the vessel wall play an important role in the pathogenesis of atherosclerosis. Systemic inflammatory reaction can be detected by showing increased plasma levels of different proinflammatory cytokines and acute-phase proteins. Infectious agents have been linked to coronary heart disease on epidemiological and pathogenetic grounds. The prevalent condition and the exact mechanism of initiation of atherosclerotic vascular disease remain unclear. Nevertheless, many similarities exist between the processes of inflammation and atherogenesis, and the evidence is growing for the role of an active inflammation in the atherosclerosis in the coronary circulation and elsewhere. Although the seroepidemiological and eradication studies have suggested a causal relationship between Helicobacter pylori (Hp) infection and coronary heart disease; the issue is still controversial. The detection of Hp specific DNA in atheromatous plaque material from coronary arteries, but more important, the reduction in restenosis of coronary vessels after Hp eradication could be interpreted as an evidence for the involvement of a Hp infection in the progression of CAD induced by a local inflammatory process.

Coronary Artery Disease↗

PubMed2006

Involvement of Helicobacter pylori infection in neuro-hormonal control of food intake.

Ghrelin and leptin are endogenous peptides that have been implicated in the control of food intake, energy homeostasis and body weight gain. Although the stomach is the major source of circulating ghrelin and partly contributes also to plasma leptin, controversy exists over the influence of gastric Helicobacter pylori (Hp) infection on the ghrelin and leptin release. To resolve this controversy, plasma immunoreactive ghrelin and leptin levels were determined in Hp-positive and Hp negative children (N=60) and in adults (N=120) and daily concentrations of these hormones were measured at 2 h intervals before and after meals. Serum levels of ghrelin and leptin as well as gastrin were measured by RIA. Hp status was assessed using (13)C-urea breath test (UBT) and serology. Children with negative UBT showed significantly higher basal serum levels of ghrelin and lower concentrations of leptin than those with positive UBT. Adults without Hp infection also showed significantly higher fasting serum levels of ghrelin and lower levels of leptin than those in Hp infected subjects. In adults, especially without Hp infection, plasma levels of ghrelin showed a marked rise before the meal and sudden decrease following the food intake, while plasma leptin did not showed significant meal-related alterations, but in general its level was significantly higher in Hp positive than Hp negative subjects. Serum gastrin concentrations were significantly elevated in both Hp positive children and adults and these levels were significantly lower in Hp negative subjects. We conclude that Hp infection in children and adults causes a marked reduction in plasma levels of ghrelin, while increasing plasma levels of leptin and gastrin. These alterations in plasma levels of gastric originated appetite-controlling hormones in Hp infected children and adults may contribute to the alterations of the appetite and dyspeptic symptoms observed in these subjects.

Adolescent↗

PubMed2006

Cannabinoids in acute gastric damage and pancreatitis.

UNLABELLED: Recent studies have shown that stimulation of cannabinoid 1 (CB1) receptor reduces the area of ischemic myocardial necrosis and affects activity of the digestive tract. The aim of the present study was to check whether the administration of CB1 receptor agonist or antagonist affects the stress-induced gastric ulceration and development of edematous pancreatitis. METHODS: Experiments were performed on rats. Gastric lesions were induced by water immersion and restrain stress (WRS). Acute pancreatitis was induced by cerulein. Prior to WRS or before and during cerulein administration, a natural endogenous ligand for CB1 receptor, anandamide was administered intraperitoneally at the dose of 0.8, 1.5 or 3.0 micromol/kg. A synthetic CB1 receptor antagonist, AM 251 (ALEXIS(R) Biochemicals) was administrated at the dose of 4 micromol/kg i.p. alone or in combination with anandamide at the dose of 1.5 micromol/kg. RESULTS: Administration of anandamide reduced gastric lesions and this effect was associated with am increase in gastric mucosal blood flow and mucosal DNA synthesis; whereas serum level of pro-inflammatory interleukin-1 beta was reduced. Treatment with AM 251 aggravated gastric damage and reversed protective effect of anandamide administration. Opposite effect was observed in the pancreas. Administration of anandamide increased dose-dependently the severity of pancreatitis. In histological examination, we observed an increase in pancreatic edema and inflammatory infiltration. Also, treatment with anandamide augmented the pancreatitis-induced increase in serum level of lipase, amylase, poly-C ribonuclease, and pro-inflammatory interleukin-1 beta; whereas pancreatic DNA synthesis was reduced. Treatment with AM 251 reduced histological and biochemical signs of pancreatic damage and reversed deleterious effect of anandamide in cerulein-induced acute pancreatitis. CONCLUSIONS: Activation of CB1 receptors evokes opposite effects in the stomach and pancreas: in the stomach, exhibits protective effect against stress-induced gastric mucosal lesions; whereas in the pancreas, increases the severity of cerulein-induced pancreatitis.

Acute Disease↗

PubMed2006

Neural aspects of ghrelin-induced gastroprotection against mucosal injury induced by noxious agents.

Ghrelin, identified in oxyntic mucosa has been recently implicated in the control of food intake and growth hormone (GH) release but whether this hormone can influence the gastric secretion and gastric mucosal integrity have been little studied. We compared the effects of intraperitoneal (i.p.) and intracerebroventricular (i.c.v.) administration of ghrelin on gastric secretion in rats equipped with gastric fistula (GF) and gastric lesions induced in rats by 75% ethanol and ischemia-reperfusion (I/R) with or without vagotomy or functional ablation of afferent sensory nerves by capsaicin. The number and the area of gastric lesions was measured by planimetry, the GBF was assessed by H(2)-gas clearance method and blood was withdrawn for the determination of the plasma ghrelin and gastrin levels. Ghrelin (5-80 microg/kg i.p. or 600-5000 ng/rat i.c.v.) increased gastric acid secretion and attenuated gastric lesions induced by ethanol and I/R. These protective effects of ghrelin were accompanied by the significant rise in the gastric mucosal blood flow (GBF) and plasma ghrelin and gastrin levels. Ghrelin given i.p. or injected i.c.v. in standard doses 20 microg/kg or 5000 ng/kg, respectively, significantly attenuated the gastric mucosal damage and significantly raised the GBF. Ethanol applied i.g. in smaller concentrations (12.5% and 25%) produced a significant increase in plasma immunorective ghrelin levels and this effect was inhibited in rats receiving ethanol in higher concentrations (75% and 100%). Ghrelin-induced protection after its i.p. or i.c.v. administration and accompanying increase in the GBF were completely abolished by vagotomy and capsaicin-deactivation of sensory nerves. Concurrent treatment with CGRP added to ghrelin restored the gastroprotective and hyperemic effects of ghrelin applied i.p. or i.c.v. in rats with capsaicin denervation. We conclude that central and peripheral ghrelin exerts a potent protective and gastric secretory effects in rats exposed to ethanol and I/R, and that these actions involve vagal nerve integrity, partially depending upon afferent nerves and hyperemia mediated by sensory neuropeptides such as CGRP released from these nerves.

Animals↗

PubMed2006

Leptin is the modulator of HSP60 gene expression in AR42J cells.

Leptin, circulating protein involved in the control of body weight and energy expenditure received attention as a modulator of immune response of the organism. Leptin receptors have been detected in the pancreas and experimental studies have shown that leptin protects the pancreas against the damage induced by caerulein overstimulation. Heat shock proteins (HSP) are endogenous proteins produced by various cells exposed to high temperature or to the noxious agents. HSP protect the cells against various environmental and endogenous stressors. The implication of HSP60 in the leptin-induced pancreatic protection has not been examined yet. The aim of this study was: to investigate the changes of HSP60 mRNA signal in the pancreatic AR42J cells subjected to caerulein and leptin. AR42J cells were incubated in standart medium at 37 degrees C for: 0, 1, 3, 5, 12 or 24 h, under basal conditions. Incubation time of 3 h was selected for the next experiments. AR42J cells were incubated in presence of caerulein (10(-11), 10(-9) or 10(-7) M), leptin (10(-8) or 10(-6) M), or combination of above. Gene expression for HSP60 was determined by RT-PCR. The mRNA signal for HSP60 has been observed in AR42J pancreatic cells under basal conditions. Incubation of AR42J cells in presence of leptin (10(-8) or 10(-6) M) resulted in the significant increase of gene expression for HSP60 in both groups of AR42J cells. Caerulein stimulation reduced mRNA signal for HSP60. The strongest mRNA signal for HSP60 has been observed after the exposition of AR42J cells to combination of leptin and caerulein. We conclude that: 1. Gene expression for HSP60 has been detected in pancreatic AR42J cells under basal conditions. 2. HSP60 gene expression was significantly increased in pancreatic AR42J cells stimulated by leptin whereas caerulein reduced this signal. 3. The strongest gene expression for HSP60 has been detected in the cells incubated with combination of caerulein and leptin.

Actins↗

PubMed2006

Melatonin in gastroprotection against stress-induced acute gastric lesions and in healing of chronic gastric ulcers.

The degree of gastric damage following to exposition of the mucosa to noxious agents depends upon a balance between the factors promoting this damage and those activating the natural defense mechanisms. Recent findings, presented in this review, provide evidence that melatonin prevents the formation of acute gastric lesions induced by stress and accelerates healing of chronic gastric ulcers due to increase in the activity of nitric oxide (NO) synthase (NOS)-NO and cyclooxygenase (COX)-prostaglandin E(2) (PGE(2)) systems resulting in the increase of mucosal blood flow and mucosal integrity. Melatonin is produced and released into the circulation by the pineal gland and, in many times larger amounts, by the gastrointestinal tract. Due to its anti-inflammatory and anti-oxidant properties, melatonin may be one of the most efficient protective factors preventing the development of acute gastric damage and accelerating healing of chronic gastric ulcers probably due to reduction in proinflammatory cytokine production, scavenging of the radical oxygen species and activation of COX-PG and NOS-NO systems as well as stimulating the afferent sensory nerves in the brain-gut axis.

Animals↗

PubMed2005

Helicobacter pylori infection and serum gastrin, ghrelin and leptin in children of Polish shepherds.

OBJECTIVE: Family unit is generally accepted as one of the contributors to Helicobacter pylori infection that is most frequently acquired in childhood, so it seems logical to diagnose and treat this infection in childhood. This study was designed to assess H. pylori prevalence in children from shepherd families having contacts with sheep. MATERIAL AND METHODS: This study involved 146 children (58 M/88 F, age 6-17 years; mean: 10.2 years) from families living in Polish Tatra Mountains with contact (group A, n=58) or without contact with sheep (group B, n=88). H. pylori status was determined by (13)C-urea breath test and was compared to 141 age- and gender-matched urban controls (group C). In both groups of mountain children, the anti-H. pylori and anti-CagA IgG were measured by ELISA and serum gastrin, ghrelin and leptin concentrations by RIA. RESULTS: The H. pylori prevalence in group A was significantly higher (58.6%) than that in group B (21.6%) and urban controls (26%). Serum gastrin concentrations were significantly higher in H. pylori-positive than in H. pylori-negative mountain children (52.2+/-5.8 pmol/L versus 22.7+/-2.1 pmol/L), while serum ghrelin and leptin concentrations were significantly lower in H. pylori-infected (741+/-112 pg/mL and 3.6+/-0.8 ng/mL) than in non-infected children (1323+/-104 pg/mL and 8.6+/-2.4 ng/mL). CONCLUSIONS: Children with sheep contact show about twice higher H. pylori prevalence and higher serum gastrin but lower ghrelin and leptin levels than those without H. pylori infection. Considering almost 100% positive 13C-urea breath test in sheep, it is reasonable to propose that H. pylori infection in shepherd children may originate from sheep and the infection might, therefore, be considered as zoonosis.

Adolescent↗

PubMed2005

Effect of moderate incremental exercise, performed in fed and fasted state on cardio-respiratory variables and leptin and ghrelin concentrations in young healthy men.

BACKGROUND: Although hormonal responses to exercise performed in fed state are well documented, far less in known about the effect of a single exercise bout, performed after overnight fasting, on cardio-respiratory responses and hormones secretion. It has been reported that recently discovered hormones as leptin and ghrelin may affect cardiovascular responses at rest. However, their effect on the cardiovascular responses to exercise is unknown. AIMS: This study was designed to determine the effect of overnight fasting on cardio- respiratory responses during moderate incremental exercise. We have hypothesised that fasting / exercise induced changes in plasma leptin / ghrelin concentrations may influence cardiovascular response. MATERIAL AND METHODS: Eight healthy non-smoking men (means +/- SE.: age 23.0 +/- 0.5 years; body mass 71.9 +/- 1.5 kg; height 179.1 +/- 0.8 cm; BMI 22.42 +/- 0.49 kg x m(-2) with VO2max of 3.71 +/- 0.10 l x min(-1)) volunteered for this study. The subjects performed twice an incremental exercise test, with the increase of power output by 30 W every 3 minutes. Tests were performed in a random order: once in the feed state--cycling until exhaustion and second, about one week later, after overnight fasting--cycling until reaching 150 W. RESULTS: In the present study we have compared the results obtained during incremental exercise performed only up to 150 W (59 +/- 2 % of VO2max) both in fed and fasted state. Heart rate measured during exercise at each power output, performed in fasted state was by about 10 bt x min(-1) (p = 0.02) lower then in fed subjects. Respiratory quotient and plasma lactate concentration in fasted state were also significantly (p<0.001) lower than in the fed state. Pre-exercise plasma leptin and ghrelin concentrations were not significantly different in fed and fasted state. Exercise induced increase in hGH was not accompanied by a significant changes in the studied gut hormones such as ghrelin, leptin, and insulin, except for plasma gastrin concentration, which was significantly (p = 0.008) lower in fasting subjects at the power output of 150 W. Plasma [IL-6] at rest before exercise performed in fasted state was significantly (p = 0.03) elevated in relation to the fed state. This was accompanied by significantly higher (p = 0.047) plasma noradrenaline concentration. Plasma IL-6 concentration at rest in fed subjects was negatively correlated with plasma ghrelin concentration (r = -0.73, p < 0.05) and positively correlated with plasma insulin concentration (r = 0.78, p < 0.05). Significant negative correlation (r = -0.90; p < 0.05) was found between plasma insulin and ghrelin concentration at rest in fed subjects. CONCLUSIONS: We have concluded that plasma leptin and ghrelin concentrations have no significant effect on the fasting-induced attenuation of heart rate during exercise. We have postulated that this effect is caused by increased plasma norepinephrine concentration, leading to the increase in systemic vascular resistance and baroreceptor mediated vagal stimulation. Moreover we believe, that the fasting-induced significant increase in plasma IL-6 concentration at rest, accompanied by higher plasma norepinephrine concentration and lower RQ, belongs to the physiological responses, maintaining energy homeostasis in the fasting state.

Adult↗

PubMed2005

Role of afferent nerves and sensory peptides in the mediation of hepatic artery buffer response.

Intrahepatic arteries are richly innervated by both adrenergic and sensory vanilloid-sensitive (capsaicin-sensitive) fibers. Stimulation of capsaicin sensitive fibers has been shown to dilate the intrahepatic vessels by both releasing sensory neuropeptides and by modulating the adrenergic tone. However the participation of capsaicin-sensitive fibers in the mediation of the hepatic artery buffer response (HABR) has not been investigated yet. To explore the involvement of sensory innervation and sensory neuropeptides in the HABR, the experiments were performed on capsaicin-denervated Wistar rats. In addition, we used selective CGRP and tachykinin receptor antagonists to test the participation of CGRP, substance P and NK-A in HABR in the rat. In anesthetized rats the hepatic artery blood flow (HABF), microcirculatory hepatic blood flow (HBF) and portal blood flow (PBF) were determined. The HABR was induced by partial occlusion of the portal vein and maintaining the PBF at 10% of its control preocclusive value. In the control HABR the hepatic artery blood flow increased by 89% (p< 0.005) whilst the HBF at the same time decreased by 32% (p< 0.005) in comparison to preocclusive HABF and HBF values. In sensory-denervated rats the resting HBF and PBF were increased by 23% (p< 0.05) and 34% (p< 0.05), respectively in comparison to the control HBF and PBF values. In this group the induction of the HABR increased the hepatic artery blood flow by only 55% (p< 0.05), whilst the HBF was reduced by 45% (p< 0.05). Pretreatment with CGRP 8-37 (CGRP receptor antagonist) and NK-1 but not NK-2 nor NK-3 receptor antagonists significantly reduced the HABF by 43% (p< 0.05) and 25% (p< 0.05) as compared to the HABF value in the control HABR group. These findings support the hypothesis that the hepatic artery buffer response induced by reduction of the portal inflow to the liver by 90% is partially mediated by activation of capsaicin-sensitive sensory fibers in the liver, probably due to local tissue ischemia and hypoxia. The observed vasodilation in the vascular bed of the hepatic artery is due to stimulation of CGRP and NK-1 receptors.

Animals↗

PubMed2005

Gastroprotective effects of flavonoids in plant extracts.

The purpose of this paper is to overview the relations between plant-originated substances and their bioactivity measured in terms of antioxidant, cytoprotective and antiulcer activities. In addition, we assessed whether these compounds are capable of affecting the gastric mucosal lesions induced by absolute ethanol applied intragastrically (i.g.). The following plant-originated flavonoid substances were considered; Solon (Sophoradin extract), Amaranth seed extract, grapefruit-seed extract (GSE) and capsaicin (extract of chilly pepper). The area of gastric mucosa lesions and gastric blood flow were measured in rats with ethanol-induced lesions without (control) and with one of the tested substances without and with capsaicin denervation of afferent nerves or administration of L-nitro-arginine (L-NNA), an inhibitor of nitric oxide synthase (NOS). Male Wistar rats, weighing 180-220 g fasted for 24 h before the study where used 100% ethanol was applied i.g. to induce gastric lesions, whose area was determined by planimetry. Gastric blood flow was assessed using electrolytic regional blood flowmeter. All tested plant-originated substances afforded gastroprotection against ethanol-induced damage and this was accompanied by increase in gastric microcirculation, both changes being reversed by pretreatment with neurotoxic dose of capsaicin or by pretreatment with L-NNA. We conclude that plant-originated flavonoid substances are highly gastroprotective probably due to enhancement of the expression of constitutive NOS and release of NO and neuropeptides such as calcitonin gene related peptide (CGRP) released from sensory afferent nerves increasing gastric microcirculation.

Animals↗