Ghrelin and oxidative stress in gastrointestinal tract

Pathophysiology of obesity-related infertility and its prevention and treatment by potential phytotherapeutics

BACKGROUND

Obesity is a complex multifactorial disease in which the accumulation of excess body fat has adverse health effects, as it can increase the risk of several problems, including infertility, in both men and women. Obesity and infertility have risen together in recent years. Against this background, the present review aims to highlight the impact of obesity on infertility and the underlying pathophysiology of obesity-related infertility (ORI) in men and women, and to provide readers with knowledge of current trends in the effective development of phytotherapeutics for its treatment.

METHODS

We thoroughly searched in PubMed, MEDLINE, Scopus, EMBASE, and Google Scholar to find all relevant papers on ORI and the therapeutic effects of phytotherapeutics on ORI in men and women.

RESULTS

The extensive search of the available literature revealed that obesity affects reproductive function through several complex mechanisms such as hyperlipidaemia, hyperinsulinaemia, hyperandrogenism, increased body mass index, disruption of the hormonal milieu, systemic inflammation, oxidative stress, alterations in epigenetics and dysbiosis. On the other hand, several studies reported that phytotherapeutics has a broad therapeutic spectrum of action by improving sex hormone homeostasis, ovarian dysfunction, menstrual cycle and inhibiting ovarian hyperplasia, as well as down-regulating ovarian apoptosis, inflammation and oxidative stress, and controlling metabolic dysfunction in obese women. Male infertility is also addressed by phytotherapeutics by suppressing lipogenesis, increasing testosterone, 3β-HSD and 17β-HSD levels, improving sperm parameters and attenuating testicular dyslipidaemia, oxidative stress, inflammation and germ cell apoptosis.

CONCLUSIONS

In the present review, we discussed the effects of obesity on reproductive dysfunction in men and women and the underlying pathophysiology of ORI. In addition, the therapeutic effect of phytotherapeutics against ORI was highlighted.

Apple (Malus domestica Borkh) leaves attenuate indomethacin-induced gastric ulcer in rats

Malus domestica Borkh, the apple tree, exhibited numerous pharmacological properties including antioxidant, neuroprotective, anti-inflammatory, anticancer and antimicrobial activities. The present work aimed to annotate the secondary metabolites from a butanol fraction of apple leaves (BLE), evaluate the gastro-protective and healing effects of this fraction against indomethacin-induced gastric ulcers in rats and to identify its mechanism of action. BLE (100, and 200 mg/kg) was orally administered in rats as an acute treatment against indomethacin-induced gastric ulcer in comparison with famotidine as reference anti-ulcer drug. The stomachs of rats were collected to determine the ulcer index, the preventive ratio, measure the activity of glutathione peroxidase (GPx), and estimate the expression of cyclooxygenase-2 (COX-2), and heat shock protein 70 (HSP70). Furthermore, we evaluated both inflammatory and oxidative stress markers in the gastric tissues. We also performed histopathological study of gastric mucosa using H&E stain and periodic Schiff base stain to evaluate both gastric injury scores and gastric mucus content respectively. Pretreatment with BLE markedly lowered the severity of gastric injury induced by indomethacin, decreased oxidative stress, inflammatory cytokines, and COX-2 expression in the examined gastric tissues. The gastric healing effect of BLE was associated with increased mucoglycoproteins, and HSP70 expression. Additionally, gastric healing effect of high dose of BLE was superior to that of famotidine in decreasing gastric injury scores, COX-2, inflammatory cytokines, lipid peroxidation and in increasing gastric mucin content, HSP70, and reduced glutathione. These findings indicate that BLE is effective in accelerating ulcer healing by boosting HSP70 expression, and decreasing COX-2 expression, oxidative stress, and gastric inflammation which might be related to the presence of 21 phytoconstituents.

Targeting Nrf2-Mediated Oxidative Stress Response in Traumatic Brain Injury: Therapeutic Perspectives of Phytochemicals

Traumatic brain injury (TBI), known as mechanical damage to the brain, impairs the normal function of the brain seriously. Its clinical symptoms manifest as behavioral impairment, cognitive decline, communication difficulties, etc. The pathophysiological mechanisms of TBI are complex and involve inflammatory response, oxidative stress, mitochondrial dysfunction, blood-brain barrier (BBB) disruption, and so on. Among them, oxidative stress, one of the important mechanisms, occurs at the beginning and accompanies the whole process of TBI. Most importantly, excessive oxidative stress causes BBB disruption and brings injury to lipids, proteins, and DNA, leading to the generation of lipid peroxidation, damage of nuclear and mitochondrial DNA, neuronal apoptosis, and neuroinflammatory response. Transcription factor NF-E2 related factor 2 (Nrf2), a basic leucine zipper protein, plays an important role in the regulation of antioxidant proteins, such as oxygenase-1(HO-1), NAD(P)H Quinone Dehydrogenase 1 (NQO1), and glutathione peroxidase (GPx), to protect against oxidative stress, neuroinflammation, and neuronal apoptosis. Recently, emerging evidence indicated the knockout (KO) of Nrf2 aggravates the pathology of TBI, while the treatment of Nrf2 activators inhibits neuronal apoptosis and neuroinflammatory responses via reducing oxidative damage. Phytochemicals from fruits, vegetables, grains, and other medical herbs have been demonstrated to activate the Nrf2 signaling pathway and exert neuroprotective effects in TBI. In this review, we emphasized the contributive role of oxidative stress in the pathology of TBI and the protective mechanism of the Nrf2-mediated oxidative stress response for the treatment of TBI. In addition, we summarized the research advances of phytochemicals, including polyphenols, terpenoids, natural pigments, and otherwise, in the activation of Nrf2 signaling and their potential therapies for TBI. Although there is still limited clinical application evidence for these natural Nrf2 activators, we believe that the combinational use of phytochemicals such as Nrf2 activators with gene and stem cell therapy will be a promising therapeutic strategy for TBI in the future.

Obesity and male infertility: multifaceted reproductive disruption

Background

The global prevalence of obesity has soared to a concerning height in the past few decades. Interestingly, the global decline in semen quality is a parallel occurrence that urges researchers to evaluate if obesity is among the most essential causatives of male infertility or subfertility.

Main body

Obesity may alter the synchronized working of the reproductive-endocrine milieu, mainly the hypothalamic-pituitary-gonadal (HPG) axis along with its crosstalks with other reproductive hormones. Obesity-mediated impairment in semen parameters may include several intermediate factors, which include physical factors, essentially increased scrotal temperature due to heavy adipose tissue deposits, and systemic inflammation and oxidative stress (OS) initiated by various adipose tissue-derived pro-inflammatory mediators. Obesity, via its multifaceted mechanisms, may modulate sperm genetic and epigenetic conformation, which severely disrupt sperm functions. Paternal obesity reportedly has significant adverse effects upon the outcome of assisted reproductive techniques (ARTs) and the overall health of offspring. Given the complexity of the underlying mechanisms and rapid emergence of new evidence-based hypotheses, the concept of obesity-mediated male infertility needs timely updates and pristine understanding.

Conclusions

The present review comprehensively explains the possible obesity-mediated mechanisms, especially via physical factors, OS induction, endocrine modulation, immune alterations, and genetic and epigenetic changes, which may culminate in perturbed spermatogenesis, disrupted sperm DNA integrity, compromised sperm functions, and diminished semen quality, leading to impaired male reproductive functions.

Endocrinopathies and Male Infertility

Male infertility is approaching a concerning prevalence worldwide, and inflicts various impacts on the affected couple. The hormonal assessment is a vital component of male fertility evaluation as endocrine disorders are markedly reversible causatives of male infertility. Precise hormonal regulations are prerequisites to maintain normal male fertility parameters. The core male reproductive event, spermatogenesis, entails adequate testosterone concentration, which is produced via steroidogenesis in the Leydig cells. Physiological levels of both the gonadotropins are needed to achieve normal testicular functions. The hypothalamus-derived gonadotropin-releasing hormone (GnRH) is considered the supreme inducer of the gonadotropins and thereby the subsequent endocrine reproductive events. This hypothalamic–pituitary–gonadal (HPG) axis may be modulated by the thyroidal or adrenal axis and numerous other reproductive and nonreproductive hormones. Disruption of this fine hormonal balance and their crosstalk leads to a spectrum of endocrinopathies, inducing subfertility or infertility in men. This review article will discuss the most essential endocrinopathies associated with male factor infertility to aid precise understanding of the endocrine disruptions-mediated male infertility to encourage further research to reveal the detailed etiology of male infertility and perhaps to develop more customized therapies for endocrinopathy-induced male infertility.

CIRCULATING GHRELIN LEVELS AND SUSCEPTIBILITY TO COLORECTAL CÂNCER

BACKGROUND AND OBJECTIVE

Considering the association between colorectal cancer (CRC) and both insulin resistance and obesity, and the prominent role of ghrelin in these metabolic disorders, we explored whether plasma levels of ghrelin were associated with CRC. Moreover, in the patients with CRC the possible correlations between ghrelin and insulin, insulin resistance, and body mass index (BMI) as an indicator of obesity were examined.

METHODS

A total of 170 subjects, including 82 cases with CRC and 88 controls were enrolled in this study. Plasma levels of ghrelin, insulin, and glucose were measured in all the subjects using ELISA and glucose oxidase methods. Furthermore, insulin resistance was assessed by calculating HOMA-IR index.

RESULTS

The cases with CRC had decreased ghrelin levels (P<0.001) and a higher HOMA-IR index (P<0.001) than controls. Interestingly, when CRC patients were stratified based on tumor site, lower ghrelin levels and a higher HOMA-IR index were observed in the patients with either colon or rectal cancer vs. controls too. Additionally, there were an age and BMI-independent negative correlation between ghrelin levels and HOMA-IR (r=-0.365, P<0.05), and an age-independent negative correlation between ghrelin levels and BMI (r=-0.335, P<0.05) in the rectal subgroup.

CONCLUSION

Our findings support a role for ghrelin in connection with insulin resistance and obesity in CRC susceptibility; however, it needs to be corroborated by further studies.

Protective and Healing Effects of Ghrelin and Risk of Cancer in the Digestive System

Ghrelin is an endogenous ligand for the ghrelin receptor, previously known as the growth hormone secretagogue receptor. This hormone is mainly produced by endocrine cells present in the gastric mucosa. The ghrelin-producing cells are also present in other organs of the body, mainly in the digestive system, but in much smaller amount. Ghrelin exhibits a broad spectrum of physiological effects, such as stimulation of growth hormone secretion, gastric secretion, gastrointestinal motility, and food intake, as well as regulation of glucose homeostasis and bone formation, and inhibition of inflammatory processes. This review summarizes the recent findings concerning animal and human data showing protective and therapeutic effects of ghrelin in the gut, and also presents the role of growth hormone and insulin-like growth factor-1 in these effects. In addition, the current data on the possible influence of ghrelin on the carcinogenesis, its importance in predicting the risk of developing gastrointestinal malignances, as well as the potential usefulness of ghrelin in the treatment of cancer, have been presented.

The Role of Gasotransmitters in Gut Peptide Actions

Although gasotransmitters nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H₂S) receive a bad connotation; in low concentrations these play a major governing role in local and systemic blood flow, stomach acid release, smooth muscles relaxations, anti-inflammatory behavior, protective effect and more. Many of these physiological processes are upstream regulated by gut peptides, for instance gastrin, cholecystokinin, secretin, motilin, ghrelin, glucagon-like peptide 1 and 2. The relationship between gasotransmitters and gut hormones is poorly understood. In this review, we discuss the role of NO, CO and H₂S on gut peptide release and functioning, and whether manipulation by gasotransmitter substrates or specific blockers leads to physiological alterations.

Potential Antioxidative, Anti-inflammatory and Immunomodulatory Effects of Ghrelin, an Endogenous Peptide from the Stomach in SARS-CoV2 Infection

The current COVID-19 pandemic is one of the most devastating events in recent history. The respiratory effects of this disease include acute respiratory distress syndrome, systemic inflammation, cytokine storm, and pulmonary fibrosis. Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, is a peptide hormone secreted mainly by the stomach. Interestingly, ghrelin possesses promising antioxidant, anti-and inflammatory effects, making it an attractive agent to reduce the complications of the SARS-CoV-2. In addition, ghrelin exerts a wide range of immunomodulatory and anti-inflammatory effects and can mitigate the uncontrolled cytokine production responsible for acute lung injury by upregulating PPARγ and down-regulating NF-κB expression. Ghrelin has also been reported to enhance Nrf2 expression in inflammatory conditions which led to the suppression of oxidative stress. The current opinion summarizes the evidence for the possible pharmacological benefits of ghrelin in the therapeutic management of SARS-CoV-2 infection.

Potentiality of ghrelin as antioxidant and protective agent

Background

Oxidative stress is the result of cellular troubles related to aerobic metabolism. Furthermore, this stress is always associated with biological responses evoked by physical, chemical, environmental, and psychological factors. Several studies have developed many approaches of antioxidant defense to diminish the severity of many diseases. Ghrelin was originally identified from the rat stomach, and it is a potent growth hormone-releasing peptide that has pleiotropic functions.

Methods

A systematic review was conducted within PubMed, ScienceDirect, MEDLINE, and Scopus databases using keywords such as ghrelin, antioxidant, oxidative stress, and systemic oxidative stress sensor.

Results

In the last decade, many studies show that ghrelin exhibits protection effects against oxidative stress derived probably from its antioxidant effects. Pieces of evidence demonstrate that systemic oxidative stress increase ghrelin levels in the plasma. The expression of ghrelin and its receptor in ghrelin peripheral tissues and extensively in the central nervous system suggests that this endogenous peptide plays an important role as a systemic oxidative stress sensor

Conclusion

The current evidence confirms that ghrelin and its derived peptides (Desacyl-ghrelin, obestatin) act as a protective antioxidant agent. Therefore, stressor modality, duration, and intensity are the parameters of oxidative stress that must be taken into consideration to determine the role of ghrelin, Desacyl-ghrelin, and obestatin in the regulation of cell death pathways.

Gut peptides and the microbiome: focus on ghrelin

PURPOSE OF REVIEW

In this review, we present recent insights into the role of the gut microbiota on gastrointestinal (GI) peptide secretion and signalling, with a focus on the orexigenic hormone, ghrelin.

RECENT FINDINGS

Evidence is accumulating suggesting that secretion of GI peptides is modulated by commensal bacteria present in our GI tract. Recent data shows that the gut microbiome impacts on ghrelinergic signalling through its metabolites, at the level of the ghrelin receptor (growth hormone secretagogue receptor) and highlights concomitant changes in circulating ghrelin levels with specific gut microbiota changes. However, the mechanisms by which the gut microbiota interacts with gut peptide secretion and signalling, including ghrelin, are still largely unknown.

SUMMARY

The gut microbiota may directly or indirectly influence secretion of the orexigenic hormone, ghrelin, similar to the modulation of satiety inducing GI hormones. Although data demonstrating a role of the microbiota on ghrelinergic signalling is starting to emerge, future mechanistic studies are needed to understand the full impact of the microbiota-ghrelin axis on metabolism and central-regulated homeostatic and non-homeostatic controls of food intake.

Ghrelin as an Anti-Sepsis Peptide: Review

Sepsis continues to produce widespread inflammation, illness, and death, prompting intensive research aimed at uncovering causes and therapies. In this article, we focus on ghrelin, an endogenous peptide with promise as a potent anti-inflammatory agent. Ghrelin was discovered, tracked, and isolated from stomach cells based on its ability to stimulate release of growth hormone. It also stimulates appetite and is shown to be anti-inflammatory in a wide range of tissues. The anti-inflammatory effects mediated by ghrelin are a result of both the stimulation of anti-inflammatory processes and an inhibition of pro-inflammatory forces. Anti-inflammatory processes are promoted in a broad range of tissues including the hypothalamus and vagus nerve as well as in a broad range of immune cells. Aged rodents have reduced levels of growth hormone (GH) and diminished immune responses; ghrelin administration boosts GH levels and immune response. The anti-inflammatory functions of ghrelin, well displayed in preclinical animal models of sepsis, are just being charted in patients, with expectations that ghrelin and growth hormone might improve outcomes in patients with sepsis.

Relationship between Apelin/APJ Signaling, Oxidative Stress, and Diseases

Apelin, a peptide hormone, is an endogenous ligand for G protein-coupled receptor and has been shown to be widely expressed in human and animal tissues, such as the central nervous system and adipose tissue. Recent studies indicate that the apelin/APJ system is involved in the regulation of multiple physiological and pathological processes, and it is associated with cardiovascular diseases, metabolic disorders, neurological diseases, ischemia-reperfusion injury, aging, eclampsia, deafness, and tumors. The occurrence and development of these diseases are closely related to the local inflammatory response. Oxidative stress is that the balance between oxidation and antioxidant is broken, and reactive oxygen species are produced in large quantities, causing cell or molecular damage, which leads to vascular damage and a series of inflammatory reactions. Hence, this article reviewed recent advances in the relationship between apelin/APJ and oxidative stress, and inflammation-related diseases, and highlights them as potential therapeutic targets for oxidative stress-related inflammatory diseases.

Circulating Irisin Levels and Redox Status Markers in Patients with Gastric Cancer: A Case-Control Study

Objective:

Irisin, mostly known as an exercise-induced fat browning myokine, has been recently detected in several cancer cells, and its potential for being utilized as a biomarker for early diagnosis of some cancers, such as Gastric cancer (GC), is the subject of speculation. The present study aims to compare serum irisin levels in GC patients and healthy controls and assess the interrelation between irisin and oxidative stress markers.

Methods:

In this case-control study, 22 newly diagnosed GC patients and 29 healthy controls were recruited based on the inclusion criteria. Serum levels of irisin were quantified in duplicates by ELISA. Oxidative stress indices, including total antioxidant power in sera, thiol group, malondialdehyde, and superoxide dismutase concentrations, were also measured in both groups. An independent-sample t-test was used to compare the means between the two studied groups.

Results:

Serum levels of irisin were significantly higher in the GC group compared with those of their healthy counterparts (p =0.032). No significant differences were observed between the two groups in terms of the serum total antioxidant power or the oxidative stress marker, including MDA, thiol groups, and SOD concentration in sera. Furthermore, there was no significant association between irisin, FRAP, the Thiol group, and the SOD activity.

Conclusion:

According to the finding, the increased serum levels of irisin in GC patients can play a potential role in the early diagnosis of the GC patients; hence, this peptide can be employed as a new diagnostic indicator of GC.

Gastric microbes associated with gastric inflammation, atrophy and intestinal metaplasia 1 year after Helicobacter pylori eradication

OBJECTIVE

Helicobacter pylori is associated with gastric inflammation, precancerous gastric atrophy (GA) and intestinal metaplasia (IM). We aimed to identify microbes that are associated with progressive inflammation, GA and IM 1 year after H. pylori eradication.

DESIGN

A total of 587 H. pylori-positive patients were randomised to receive H. pylori eradication therapy (295 patients) or placebo (292 patients). Bacterial taxonomy was analysed on 404 gastric biopsy samples comprising 102 pairs before and after 1 year H. pylori eradication and 100 pairs before and after 1 year placebo by 16S rRNA sequencing.

RESULTS

Analysis of microbial sequences confirmed the eradication of H. pylori in treated group after 1 year. Principal component analysis revealed distinct microbial clusters reflected by increase in bacterial diversity (p<0.00001) after H. pylori eradication. While microbial interactions remained largely unchanged after placebo treatment, microbial co-occurrence was less in treated group. Acinetobacter lwoffii, Streptococcus anginosus and Ralstonia were enriched while Roseburia and Sphingomonas were depleted in patients with persistent inflammation 1 year after H. pylori eradication. A distinct cluster of oral bacteria comprising Peptostreptococcus, Streptococcus, Parvimonas, Prevotella, Rothia and Granulicatella were associated with emergence and persistence of GA and IM. Probiotic Faecalibacterium praustznii was depleted in subjects who developed GA following H. pylori eradication. Functional pathways including amino acid metabolism and inositol phosphate metabolism were enriched while folate biosynthesis and NOD-like receptor signalling decreased in atrophy/IM-associated gastric microbiota.

CONCLUSION

This study identified that gastric microbes contribute to the progression of gastric carcinogenesis after H. pylori eradication.

Ghrelin as an anti-inflammatory and protective agent in ischemia/reperfusion injury

Ischemia/reperfusion (I/R) continue to be the most frequent cause of damaged tissues. Injured tissues resulted from the first ischemic insult, which is determined by the interruption in the blood supply, followed by subsequent impairment induced by reperfusion. In addition, ischemia-reperfusion injury is mediated by tumor necrosis factor (TNF) and other cytokines that activate complements and proteases responsible for free radical production. However, earlier studies have reported the protective roles of bioactive peptides during ischemia reperfusion injury. In fact, ghrelin is a peptide hormone discovered since 1999 as GH secretagogue and its production was identified in gastric X/A-like endocrine cells in rats and P/D1 type cells in humans. To date, this peptide receives growing attention due to its pleiotropic action in the organism and its role in maintaining energy homeostasis. Ghrelin is also involved in stress responses, assuming a modulatory action on immune pathways. Previous studies have identified many other functions related to an anti-inflammatory role in ischemia reperfusion injury. Under these challenging conditions, studies described acylated and unacylated ghrelin in activation and/or inhibition processes related to ischemia-reperfusion injury. The aim of this article is to provide a minireview about ghrelin mechanisms involved in the proinflammatory response of I/R injury. However, the regulatory processes of ghrelin in this pathologic event are still very limited and warrant further investigation.

Oxidative stress in exercise training: the involvement of inflammation and peripheral signals

The evidence about the health benefits of regular physical activity is well established. Exercise intensity is a significant variable and structured high-intensity interval training (HIIT) has been demonstrated to improve both whole-body and skeletal muscle metabolic health in different populations. Conversely, fatigue accumulation, if not resolved, leads to overwork, chronic fatigue syndrome (CFS), overtraining syndrome up to alterations of endocrine function, immune, systemic inflammation, and organic diseases with health threat. In response to temporary increases in stress during training, some athletes are unable to maintain sufficient caloric intake, thus suffering a negative energy balance that causes further stress. The regulation of the energy balance is controlled by the central nervous system through an elaborate interaction of the signalling that involves different tissues such as leptin, adiponectin and ghrelin whose provide important feedback to the hypothalamus to regulate the energy balance. Although exercise-induced reactive oxygen species are required for normal force production in muscle, high levels of ROS appear to promote contractile dysfunction. However, a high level of oxidative stress in may induce a rise in inflammatory markers and a disregulation in expression of adiponectin, leptin and grelin.

A descriptive report of the selenium distribution in tissues from pigs with mulberry heart disease (MHD)

Background

Mulberry Heart Disease (MHD) is a condition affecting mainly young pigs in excellent body condition. Feed efficient pigs showing high average daily gains are more likely to be affected. MHD has been described as a challenge in Norwegian pig production over the last decade despite abundant supplies of vitamin E, and selenium (Se) close to the upper limits set by the EU. From 2015 to 2017, samples from documented MHD field cases were collected and compared with controls regarding post mortem findings and Se concentrations in numerous internal and external organs were determined in order to characterize the Se distribution, and to identify any differences between MHD cases and controls.

Case presentation

Eight MHD cases from commercial farms and a pet pig producer located in the South West and East of Norway, and three control animals originating from these farms were included in this study. MHD cases and controls were weaned pigs with an average bodyweight (BW) of 17 kg (range 9 to 46 kg BW), with the exception of one pet piglet (Mangalica, 6 kg BW) that had only received sow milk. Selenium was determined in samples from the cardiovascular, digestive, immune, endocrine, integumentary, muscular, respiratory and urinary systems using inductively coupled plasma mass spectrometry (QQQ ICP-MS). All pigs with MHD suffered sudden deaths. Control animals were euthanized without being bled prior to necropsy and sampling. Significantly different mean Se concentrations between MHD cases and controls were found in cardiac samples as well as almost all skeletal muscles (P < 0.05). Based on the samples from ten different muscles (except the cardiac samples), mean Se concentrations in MHD cases were 0.34 (0.01) mg/ kg DM compared with 0.65 (0.02) mg/ kg DM in control pigs (P < 0.0001). In cardiac samples, mean Se concentrations from MHD cases were 0.87 (0.02) mg/ kg DM vs. 1.12 (0.04) mg/ kg DM (P < 0.0001). Additionally, significantly lower Se concentrations compared with controls were found in the liver as well as the caecum, duodenum, gastric ventricle, jejunum, kidney, skin and thymus samples.

Conclusions

Based on the present work, the current common practice regarding tissue analyses in MHD cases could be refined to include other organs than liver and heart. The evident differences in mean Se concentrations in 9 out of 10 samples from the muscular system, could make such samples relevant for complementary measurements of Se concentrations to help confirm the MHD diagnosis. We find it interesting that although our limited number of sampled pigs are different in terms of genetics, size and feeding regimes, the variation of Se concentrations in a given organ was low between MHD cases. Since this report includes a limited number of MHD cases and controls, our results should be corroborated by a controlled, larger study.

Eradication therapy for Helicobacter pylori infection improves nutrition status in Japanese hemodialysis patients: a pilot study

Plasma ghrelin level is influenced by Helicobacter pylori (H. pylori) status and the severity of gastric mucosal atrophy, and the ghrelin level is associated with nutrition status in hemodialysis patients. Here, we investigated the efficacy of H. pylori eradication therapy in improving nutrition status in relation to the ghrelin level in H. pylori-positive hemodialysis patients. Of H. pylori-positive patients receiving hemodialysis at 8 dialysis center, 21 patients underwent gastroduodenoscopy for evaluation of the severity of gastric atrophy, and nutrition markers and plasma ghrelin levels before and 1 year after H. pylori eradication therapy were evaluated. Serum cholinesterase level was significantly increased after H. pylori eradication compared with the level before eradication (303.2 ± 76.0 vs 287.3 ± 68.1 IU/L, p = 0.029). In particular, cholesterol (before, 196.6 ± 23.2 mg/dl; after, 206.1 ± 25.9 mg/dl, p = 0.042) and cholinesterase levels (before, 296.9 ± 70.8 IU/L; after, 316.4 ± 73.8 IU/L, p = 0.049) increased more strongly in patients with mild–moderate atrophy than those with severe atrophy, irrespective of improvement of plasma acyl-ghrelin and desacyl-ghrelin levels after eradication therapy. In conclusion, H. pylori eradication may improve nutrition status by increasing serum cholinesterase and cholesterol levels in hemodialysis patients, especially those with mild and moderate gastric mucosal atrophy.

Reactive oxygen species and male reproductive hormones

Reports of the increasing incidence of male infertility paired with decreasing semen quality have triggered studies on the effects of lifestyle and environmental factors on the male reproductive potential. There are numerous exogenous and endogenous factors that are able to induce excessive production of reactive oxygen species (ROS) beyond that of cellular antioxidant capacity, thus causing oxidative stress. In turn, oxidative stress negatively affects male reproductive functions and may induce infertility either directly or indirectly by affecting the hypothalamus-pituitary-gonadal (HPG) axis and/or disrupting its crosstalk with other hormonal axes. This review discusses the important exogenous and endogenous factors leading to the generation of ROS in different parts of the male reproductive tract. It also highlights the negative impact of oxidative stress on the regulation and cross-talk between the reproductive hormones. It further describes the mechanism of ROS-induced derangement of male reproductive hormonal profiles that could ultimately lead to male infertility. An understanding of the disruptive effects of ROS on male reproductive hormones would encourage further investigations directed towards the prevention of ROS-mediated hormonal imbalances, which in turn could help in the management of male infertility.

New Medical Approach to Functional Dyspepsia, from Core Symposium 3, Japan Gastroenterological Association 2015-2017

In the annual meeting of the Japan Gastroenterological Association (JGA), the scientific organizing committee selected the serial topics for the core symposium. One of the core symposia held during 2015-2017 was entitled "New medical approach to functional dyspepsia (FD)." In 2015, the subtitle of this symposium was "Helicobacter pylori gastritis and FD." In 2016, the subtitle of this symposium was "overlap with other functional GI disorders." In 2017, the subtitle was "therapeutic approach to FD." During these 3 years, a total of 24 presentations were included in Core Symposium 3 and deep and intensive discussions were carried out.

Analysis of the Relationship between Helicobacter pylori Infection and Diabetic Gastroparesis

Background:

Whether Helicobacter pylori infection is associated with diabetic gastroparesis (DGP) is unclear. This study aimed to investigate the potential correlation between H. pylori infection and DGP.

Methods:

In this study, 163 patients with type 2 diabetes mellitus and 175 nondiabetic patients who were treated in our department were divided into DGP, simple diabetes, non-DGP (NDG), and normal groups based on their conditions. The H. pylori infection rate in each group was calculated. H. pylori eradication therapy was performed for patients with H. pylori infection in each group. The eradication rates were compared between the groups, and the improvements in gastroparesis-associated symptoms were compared before and after treatment in patients with DGP.

Results:

The H. pylori infection rate was 74.6% in the DGP group, which was significantly higher than that in the simple diabetes (51.1%, P < 0.01), NDG (57.7%, P < 0.05), and normal groups (48.0%, P < 0.01). With increased disease course, the incidence of DGP and the H. pylori infection rate gradually increased (P < 0.05). In the DGP group, the incidences of upper abdominal pain and distention, early satiety, and anorexia were 75.5%, 66.0%, and 67.9%, respectively, before eradication treatment; and 43.4%, 35.8%, and 39.6%, respectively, after eradication treatment, and the difference was statistically significant (P < 0.01). In patients with DGP with successful H. pylori eradication, the number of barium strips discharged after eradication was 5.9 ± 1.0, which was significantly larger than that before treatment (4.1 ± 0.7, P < 0.01). In addition, the number of barium strips discharged was significantly larger in patients with DGP with successful H. pylori eradication than those with failed H. pylori eradication (P < 0.01).

Conclusions:

DGP development might be associated with H. pylori infection. H. pylori eradication can effectively improve dyspepsia-associated symptoms and delayed gastric emptying in patients with DGP.

Abscisic acid: a novel uterine stimulator in normal and diabetic rats

Diabetes is usually associated with alterations in myometrial contractility with altered oxytocin responsiveness that increase the incidence of fetal and maternal morbidity and mortality. Pancreatic β-cells release abscisic acid (ABA) in response to glucose, which in turn potentiates insulin secretion. The aim of the study was to find out the effect of ABA on the uterine contractility in normal and diabetic induced rats and tried to detect its possible underlying signaling pathway. Adult non-pregnant female rats were divided into normal nondiabetic group (n = 27) and diabetic group (n = 12). The effect of ABA on the normal and diabetic isolated myometrium was determined alone or after different blockers. Spontaneous diabetic myometrial contraction showed significant decrease and less responsiveness to oxytocin, KCL, and acetylcholine than nondiabetic samples. ABA showed 60% of oxytocin stimulatory effects on myometrial contraction in a dose-response manner in both groups. Meanwhile, this effect was decreased after blocking L-type calcium channels and completely abolished after blocking prostaglandin F (FP) and inositol trisphosphate (IP₃) receptors. ABA is found to have an uterotonic effect that is mediated mainly via FP receptor through increasing the level of IP₃. So, ABA by its novel effect could be beneficial as pre-labor prescription, especially in diabetic females.

Role of NRF2 in protection of the gastrointestinal tract against oxidative stress

The gastrointestinal tract is exposed to a variety of noxious factors, such as Helicobacter pylori, nonsteroidal anti-inflammatory drugs, gastric acid, ischemia-reperfusion, and mental stresses. Theses stressors generate free radicals within gastrointestinal tissues, causing organ injury and functional disturbance. Although the gastrointestinal tract can withstand such oxidative stresses to some extent by enhancing its antioxidant system via nuclear factor erythroid 2-related factor 2-Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1-mediated pathways, acute or chronic exposure to oxidative stress can cause several gastrointestinal tract disorders, such as inflammation, ulcers, cancers, and various functional disturbances. Recent studies have demonstrated that some natural compounds and drugs can upregulate the nuclear factor erythroid 2-related factor 2-mediated antioxidant system, ameliorating or preventing these disorders. Although these compounds may be useful as chemopreventive agents, sufficient evidence for their clinical efficacy has not yet been provided. In addition, it is important to note that excessive nuclear factor erythroid 2-related factor 2 stimulation can be harmful to human health, especially from the standpoint of tumor biology.

Helicobacter pylori and corpus gastric pathology are associated with lower serum ghrelin

AIM

To evaluate the association of Helicobacter pylori (H. pylori), cagA genotype, and type of gastric pathology with ghrelin, leptin and nutritional status.

METHODS

Fasted dyspeptic adults (18-70 years) referred for an upper digestive endoscopy were enrolled in this cross-sectional study. Height and weight were assessed for body mass index (BMI) calculation. A sociodemographic survey was administered and nutrient intake was evaluated with 24 h dietary recalls. Serum total ghrelin and leptin levels were analyzed by enzyme-linked immunosorbent assay. ¹³C-Urea Breath Test was performed and four gastric biopsies were obtained during endoscopy for histopathology and H. pylori DNA amplification and genotyping. Data analysis was performed using χ², Mann-Whitney U, Kruskal-Wallis tests, Spearman’s correlation and linear regression.

RESULTS

One hundred and sixty-three patients (40.8 ± 14.0 years), 98/65 females/males, were included. Overall, persistent H. pylori prevalence was 53.4% (95%CI: 45.7%-65.8%). Neither nutrient intake nor BMI differed significantly between H. pylori positive and negative groups. Serum ghrelin was significantly lower in infected patients [median 311.0 pg/mL (IQR 230.0-385.5)] than in uninfected ones [median 355.0 pg/mL (IQR 253.8-547.8)] (P = 0.025), even after adjusting for BMI and gender (P = 0.03). Ghrelin levels tended to be lower in patients carrying cagA positive strains both in the antrum and the corpus; however, differences with those carrying cagA negative strains did not reach statistical significance (P = 0.50 and P = 0.49, respectively). In addition, the type and severity of gastric pathology in the corpus was associated with lower serum ghrelin (P = 0.04), independently of H. pylori status. Conversely, leptin levels did not differ significantly between infected and uninfected patients [median 1.84 ng/mL (0.80-4.85) vs 1.84 ng/mL (0.50-5.09), (P = 0.51)].

CONCLUSION

H. pylori infection and severity of gastric corpus pathology are associated with lower serum ghrelin. Further studies could confirm a lower ghrelin prevalence in cagA-positive patients.

Daily intake of broccoli sprouts normalizes bowel habits in human healthy subjects

Chronic oxidative stress impairs regular defecation. Sulforaphane (SFN) enhances anti-oxidant systems, ameliorating oxidative injury. SFN inhibits overgrowth of anaerobic microflora and protects small intestine from oxidative injury. We assessed whether daily intake of SFN-rich broccoli sprouts (BS) improves defecation in humans. Forty-eight subjects, with a constipation scoring system (CSS) >2 points, were assigned to either the BS group (n = 24) or the alfalfa sprouts (AS) group (n = 24), and were requested to eat 20 g daily of raw BS or AS, respectively, for 4 weeks. BS contains 4.4 mg/g sulforaphane glucosinolates (SGS), while AS contains no SGS. CSS-based questionnaires were performed to evaluate bowel habit. Stool samples were collected to evaluate intestinal microflora using a terminal restriction fragment length polymorphism flora analysis. Intervention with BS, but not AS, caused a significant decrease in the duration of attempted defecation and the total CSS score. Intervention with BS decreased the percentage of Bifidobacterium in the stool. These results suggest that daily intake of BS improves bowel habit in human subjects. Since BS treatment enhance antioxidant enzyme activities, these effects of BS appear to relate with the SFN-mediated modulation of the intestinal motility during exposure to oxidative stress. (UMIN Clinical Trial Registration Number: UMIN-000021207).

Anti-inflammatory and antioxidative effects of Camellia oleifera Abel components

Camellia oleifera Abel is a member of Camellia, and its seeds are used to extract Camellia oil, which is generally used as cooking oil in the south of China. Camellia oil consists of unsaturated fatty acids, tea polyphenol, squalene, saponin, carrot element and vitamins, etc. The seed remains after oil extraction of C. oleifera Abel are by-products of oil production, named as Camellia oil cake. Its extracts contain bioactive compounds including sasanquasaponin, flavonoid and tannin. Major components from Camellia oil and its cake have been shown to have anti-inflammatory, antioxidative, antimicrobial and antitumor activities. In this review, we will summarize the latest advance in the studies on anti-inflammatory or antioxidative effects of C. oleifera products, thus providing valuable reference for the future research and development of C. oleifera Abel.

Mechanistic evaluation of gastroprotective effects of Kangfuxin on ethanol-induced gastric ulcer in mice

This study was designed to evaluate the gastroprotective effect of Kangfuxin (KFX), a Chinese patent medicine constituent isolated from American cockroach, on ethanol-induced gastric ulcer in mice and to elucidate the potential mechanisms of the effect involved. According to the results, mice treated with alcohol appeared obvious gastric mucosal injury, while treatment with Cimetidine (a positive control) and KFX significantly relieved the damage, along with decreased oxidative stress and apoptosis indexes. Subsequently, we conducted a label-free quantitative proteomic (LFQ) and found that NF-κB and PI3K/AKT signaling pathway participated in gastroprotective effect of KFX. Furthermore, Western blot analysis revealed that KFX treatment inhibited the expression of TNF-α, IL-1β, greatly reduced the phosphorylation level of IκB and repressed the nuclear translocation of NF-κB p65, which demonstrated that KFX inhibited the activation of NF-κB pathway. Meanwhile, the PI3K/AKT pathway was also involved in regulating the anti-inflammation effect. These findings define for the first time that the gastroprotective effects of KFX against gastric ulcer can be attributed to its role in NF-κB inhibition.

Constituents of leaves from Bauhinia curvula Benth. exert gastroprotective activity in rodents: role of quercitrin and kaempferol

The Bauhinia genus is known as "Pata-de-Vaca" and a wide variety of these species are used in Brazilian folk medicine due to their gastroprotective properties. This study aimed to investigate the antiulcer efficacy of the hydroalcoholic extract from B. curvula (HEBC) leaves, as well as its semi-purified fraction (SPFr) and the contribution of their phytochemicals constituents for this effect. For that, ethanol 60%/HCl 0.3 M- and indomethacin-induced gastric ulcer were performed in rodents. Gastric ulcerated tissues were processed for histological, histochemical and biochemical analysis. The oral treatment with HEBC and SPFr decreased the gastric ulcer induced by ethanol/HCl in mice and by indomethacin (only HEBC) in rats. The gastroprotective effect of HEBC was abolished in mice pretreated with Nω-Nitro-L-arginine methyl ester, N-Ethylmaleimide, glibenclamide or indomethacin. Both HEBC and SPFr reduced myeloperoxidase activity in parallel with a decrease of lipoperoxides content at the site of the lesion. On the other hand, HEBC did not alter volume, pH, total acidity or pepsin activity of acid gastric secretion in rats, and neither inhibited the in vitro H(+),K(+)-ATPase activity. Additionally, the compounds identified and isolated from the SPFr, the flavonoids quercitrin (65%) and kaempferol (35%), were able to diminish the extent of ulcerated area induced by both ethanol/HCl and indomethacin. Taking together, these findings show that B. curvula extracts present gastroprotective effect, mainly explained by the presence of flavonoids quercitrin and kaempferol, which may possibly improve the defensive factors of gastric mucosa.

Short-term administration of melatonin or ghrelin on diabetic rats: effects on angiotensin II and vasopressin-induced uterine contractility

The aim of the present study was to investigate the effects of Angiotensin II (Ang II) and Arginin-Vasopressin (AVP) on contractility of non-pregnant uterus in diabetic Wistar rats and to explore whether one-week administration of Melatonin (MLT) or Ghrelin (GHR) will change the response of diabetic uterine muscle to AngII and AVP. Uterine horns, prepared by the method of isolated tissues were investigated as well as glycemic profile, blood pressure and body weight. The research of smooth muscle contractions was made by a new method of analysis, characterizing in detail the various phases of the myometrial activity. Differences in the development of the peptide-mediated smooth muscle contractions depending on the phase of the estrous cycle were observed. Experimental diabetes had a pronounced negative effect on force and time-parameters of AngII and AVP-stimulated uterine contractions. Administration of GHR or MLT had a beneficial effect on the glycemic status of diabetic rats and partially improved the response of uterine preparations to the peptides. The application of MLT increased both force and time-parameters of Ang II-and AVP-stimulated uterine contractions while treatment with GHR increased power characteristics and shortened contraction and relaxation of the smooth muscle process.

Changes in plasma ghrelin and leptin levels in patients with peptic ulcer and gastritis following eradication of Helicobacter pylori infection

Background

Helicobacter pylori (H. pylori) infection and eradication therapy have been known to influence gastric ghrelin and leptin secretion, which may lead to weight gain. However, the exact relationship between plasma ghrelin/leptin levels and H. pylori infection has remained controversial. The aim of this study was to investigate plasma ghrelin and leptin levels in H. pylori-positive and -negative patients, to compare the two levels of the hormones before and after H. pylori eradication, and to examine the correlation between body mass index (BMI) and active ghrelin or leptin levels, as well as that between atrophic pattern and active ghrelin or leptin levels.

Methods

Seventy-two H. pylori-positive patients who underwent upper gastrointestinal endoscopy, 46 diagnosed as having peptic ulcer and 26 as atrophic gastritis, were enrolled. Control samples were obtained from 15 healthy H. pylori-negative volunteers. The extent of atrophic change of the gastric mucosa was assessed endoscopically. Body weight was measured and blood was collected before and 12 weeks after H. pylori eradication therapy. Blood samples were taken between 8 and 10 AM after an overnight fast.

Results

Plasma ghrelin levels were significantly lower in H. pylori-positive patients than in H. pylori-negative patients. In particular, plasma active ghrelin levels were significantly lower in patients with gastritis compared with patients with peptic ulcer. Plasma ghrelin levels decreased after H. pylori eradication in both peptic ulcer and gastritis patients, while plasma leptin levels increased only in peptic ulcer patients. Plasma leptin levels and BMI were positively correlated, and active ghrelin levels and atrophic pattern were weakly negatively correlated in peptic ulcer patients.

Conclusion

H. pylori infection and eradication therapy may affect circulating ghrelin/leptin levels. This finding suggests a relationship between gastric mucosal injury induced by H. pylori infection and changes in plasma ghrelin and leptin levels.

Pathogenesis of diabetic gastrointestinal dysfunction

Diabetic gastrointestinal dysfunction is a common complication in patients with diabetes mellitus. Most of the symptoms are related to impaired gastrointestinal function. The pathogenesis and etiology of diabetic gastroenteropathy are complex, involving the parasympathetic and sympathetic nervous systems, enteric neurons, smooth muscle cells, the network of interstitial cells of Cajal, cholinergic receptors and neuronal nitric oxide synthase. This article reviews the pathogenesis of diabetic gastrointestinal dysfunction.

Increase in plasma acyl ghrelin levels is associated with abatement of dyspepsia following Helicobacter pylori eradication

BACKGROUND

Ghrelin has been indicated as one of the etiological factors in functional dyspepsia (FD).

METHODS

We analyzed 179 patients with FD (based on the Rome III criteria) and 103 asymptomatic healthy individuals (controls) who had undergone endoscopy at Seoul National University Bundang Hospital from February 2011 to June 2014. FD patients were classified into three groups by means of a self-reported questionnaire: patients with postprandial distress syndrome (PDS; n = 49), patients with epigastric pain syndrome (EPS; n = 45), and patients with a combination of these two types (mixed group; n = 85). The fasting blood levels of acyl ghrelin and desacyl ghrelin and messenger RNA (mRNA) expression of preproghrelin in the fundic mucosa were measured by ELISAs and reverse transcription quantitative real-time PCR, respectively. One year after participant enrollment, they were measured again in 79 participants and the changes in the values were compared according to Helicobacter pylori eradication or symptom response.

RESULTS

Plasma acyl ghrelin level was lower in the PDS group than in the control and EPS groups (control group 14.1 fmol/mL, PDS group 8.9 fmol/mL, EPS group 13.8 fmol/mL, mixed group 11.3 fmol/mL; P = 0.003 and P = 0.012, respectively). One year after the eradication of H. pylori, plasma acyl ghrelin level was increased and gastric preproghrelin mRNA expression was upregulated (P = 0.004 and P < 0.001, respectively). Patients with abatement of symptoms demonstrated an increase in plasma acyl ghrelin level (from 11.51 to 21.00 fmol/L, P = 0.040).

CONCLUSIONS

Our results suggest that plasma acyl ghrelin plays a role in the development of PDS. H. pylori eradication upregulates preproghrelin mRNA expression and increases plasma acyl ghrelin level, contributing to the abatement of PDS symptoms.

Effects of ghrelin, leptin and melatonin on the levels of reactive oxygen species, antioxidant enzyme activity and viability of the HCT 116 human colorectal carcinoma cell line

Obesity is associated with an increased risk of certain types of cancer, including colon cancer. Adipose tissue is an endocrine organ that produces biologically active substances, such as leptin and ghrelin. Recent research has suggested that adipose-derived hormones may be associated with mechanisms linked to tumorigenesis and cancer progression. Furthermore, previous studies have demonstrated that pineal gland-derived melatonin possesses important oncostatic and antioxidant properties. The present study aimed to determine the effects of the adipokines ghrelin and leptin, and the melatonin on intracellular levels of reactive oxygen species (ROS) and the activity of selected antioxidant enzymes, such as superoxide dismutase, catalase (CAT) and glutathione peroxidase. The effects of these compounds were also determined on the viability of HCT 116 human colorectal carcinoma cells in vitro. The pro-oxidant and growth inhibitory effects of melatonin resulted in an accumulation of ROS and decreased antioxidant capacity in melatonin-treated cells. Ghrelin administration alone caused a significant decrease in the levels of ROS, due to an increased activity of CAT in the HCT 116 cells. In addition, the present study observed increased lipid peroxidation following melatonin treatment, and decreased levels of malondialdehyde following ghrelin or leptin treatment. In conclusion, ghrelin, leptin and melatonin have various influences on the antioxidant capacity of HCT 116 cells. Compared with the adipokines, treatment with melatonin increased ROS levels and decreased cellular viability.

Alterations of ghrelin with weights and correlation among ghrelin, cytokine and survival in patients receiving chemoradiotherapy for gastrointestinal cancers

AIM

This study involved 30 patients (16 had gastric, 9 pancreatic and 5 gall bladder cancer) who had received concomitant chemoradiotherapy (CRT). Blood ghrelin and IL-6 values were compared before, in the last week of, and 3 months after CRT. Meanwhile, changes in body weight of patients were also investigated with changes in ghrelin and IL-6 levels before, in the last week of, and after radiotherapy (RT).

METHODS

Informed consent of the patients and the ethical committee approval from Cukurova University Medical Faculty were taken. Blood ghrelin and IL-6 levels were measured by using the ELISA method. Survival analysis was performed by the Kaplan Maier method, and data were evaluated by using the SPSS 19.0 package. Categorical measurements were calculated as numbers and percentages, whereas numerical data were summarized as mean and standard deviation.

RESULTS

The correlation between ghrelin and IL-6 values at the baseline of RT and overall survival rates at the end of the 30-month follow up was analyzed. Accordingly, ghrelin values were also changed in line with changes in patients' weights (P < 0.001). Patients with ghrelin values above 35 pg/ml before RT had longer survival rates at the end of the 30-month follow up (P = 0.001). Overall survival rates in patients with IL-6 value at or below 3.9 pg/ml before RT were longer than patients with IL-6 value above 3.9 pg/ml (P = 0.021).

CONCLUSION

Therefore, the initiation of ghrelin analogue prophylactically in patients receiving chemoradiotherapy with gastrointestinal system malignancies can both prevent weight loss by increasing appetite and decrease severity of inflammation, thereby increasing survival.

Effects of ghrelin on protein expression of antioxidative enzymes and iNOS in the rat liver

INTRODUCTION

We investigated the effects of ghrelin on protein expression of the liver antioxidant enzymes superoxide dismutases (SODs), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR), nuclear factor κB (NFκB) and inducible nitric oxide synthase (iNOS). Furthermore, we aimed to investigate whether extracellular regulated protein kinase (ERK1/2) and protein kinase B (Akt) are involved in ghrelin-regulated liver antioxidant enzymes and iNOS protein expression.

MATERIAL AND METHODS

Male Wistar rats were treated with ghrelin (0.3 nmol/5 µl) injected into the lateral cerebral ventricle every 24 h for 5 days, and 2 h after the last treatment the animals were sacrificed and the liver excised. The Western blot method was used to determine expression of antioxidant enzymes, iNOS, phosphorylation of Akt, ERK1/2 and nuclear factor κB (NFκB) subunits 50 and 65.

RESULTS

There was significantly higher protein expression of CuZnSOD (p < 0.001), MnSOD (p < 0.001), CAT (p < 0.001), GPx, (p < 0.001), and GR (p < 0.01) in the liver isolated from ghrelin-treated animals compared with control animals. In contrast, ghrelin significantly (p < 0.01) reduced protein expression of iNOS. In addition, phosphorylation of NFκB subunits p65 and p50 was significantly (p < 0.001 for p65; p < 0.05 for p50) reduced by ghrelin when compared with controls. Phosphorylation of ERK1/2 and of Akt was significantly higher in ghrelin-treated than in control animals (p < 0.05 for ERK1/2; p < 0.01 for Akt).

CONCLUSIONS

The results show that activation of Akt and ERK1/2 is involved in ghrelin-mediated regulation of protein expression of antioxidant enzymes and iNOS in the rat liver.

Brain-gut axis in the pathogenesis of Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection is the main pathogenic factor for upper digestive tract organic diseases. In addition to direct cytotoxic and proinflammatory effects, H. pylori infection may also induce abnormalities indirectly by affecting the brain-gut axis, similar to other microorganisms present in the alimentary tract. The brain-gut axis integrates the central, peripheral, enteric and autonomic nervous systems, as well as the endocrine and immunological systems, with gastrointestinal functions and environmental stimuli, including gastric and intestinal microbiota. The bidirectional relationship between H. pylori infection and the brain-gut axis influences both the contagion process and the host’s neuroendocrine-immunological reaction to it, resulting in alterations in cognitive functions, food intake and appetite, immunological response, and modification of symptom sensitivity thresholds. Furthermore, disturbances in the upper and lower digestive tract permeability, motility and secretion can occur, mainly as a form of irritable bowel syndrome. Many of these abnormalities disappear following H. pylori eradication. H. pylori may have direct neurotoxic effects that lead to alteration of the brain-gut axis through the activation of neurogenic inflammatory processes, or by microelement deficiency secondary to functional and morphological changes in the digestive tract. In digestive tissue, H. pylori can alter signaling in the brain-gut axis by mast cells, the main brain-gut axis effector, as H. pylori infection is associated with decreased mast cell infiltration in the digestive tract. Nevertheless, unequivocal data concerning the direct and immediate effect of H. pylori infection on the brain-gut axis are still lacking. Therefore, further studies evaluating the clinical importance of these host-bacteria interactions will improve our understanding of H. pylori infection pathophysiology and suggest new therapeutic approaches.

Ghrelin contributes to protection of hepatocellular injury induced by ischaemia/reperfusion

BACKGROUND & AIMS

Ghrelin, a gut hormone with pleiotropic effects, may act as a protective signal in parenchymal cells. We investigated the protective effects of ghrelin on hepatocytes after ischaemia/reperfusion (I/R).

METHODS

Hepatic injury was assessed by measurement of plasma alanine aminotransferase (ALT) and lactate dehydrogenase (LDH), histological analysis, and TUNEL assay. Effects of exogenous ghrelin and ghrelin receptor gene deletion on I/R induced injury of liver were evaluated.

RESULTS

Ischaemia/reperfusion induced a profound injury to hepatocytes. This was accompanied by elevations in plasma ALT and LDH. Pretreatment with ghrelin significantly reduced elevations in plasma ALT and LDH, and attenuated tissue damage induced by hepatic I/R in mice. Hepatic injury induced by I/R was more pronounced in ghrelin receptor gene null mice. Ghrelin administration blocked the up-regulation of AMP-activated protein kinase (AMPK) activity induced by hepatic I/R.

CONCLUSIONS

This study demonstrates that ghrelin contributes to the cytoprotection during hepatic I/R.

Regulation of oxidative stress and somatostatin, cholecystokinin, apelin gene expressions by ghrelin in stomach of newborn diabetic rats

The aim of the study was to determine whether ghrelin treatment has a protective effect on gene expression and biochemical changes in the stomach of newborn streptozotocin (STZ) induced diabetic rats. In this study, four groups of Wistar rats were used: control, ghrelin control, diabetic and diabetic+ghrelin. The rats were sacrificed after four weeks of treatment for diabetes. The gene expressions of: somatostatin, cholecystokinin, apelin and the altered active caspase-3, active caspase-8, proliferating cell nuclear antigen, were investigated in the pyloric region of the stomach and antioxidant parameters were measured in all the stomach. Although ghrelin treatment to diabetic rats lowered the stomach lipid peroxidation levels, the stomach glutathione levels were increased. Exogenous ghrelin caused an increased activities of stomach catalase, superoxide dismutase, glutathione reductase and glutathione peroxidase in diabetic rats. Numbers of somatostatin, cholecystokinin and proliferating cell nuclear antigen immunoreactive cells decreased in the diabetic+ghrelin group compared to the diabetic group. Apelin mRNA expressions were remarkably less in the diabetic+ghrelin rats than in diabetic rats. The results may indicate that ghrelin treatment has a protective effect to some extent on the diabetic rats. This protection is possibly accomplished through the antioxidant activity of ghrelin observed in type 2 diabetes. Consequently exogenous ghrelin may be a candidate for therapeutic treatment of diabetes.

Plasma insulin, leptin, adiponectin, resistin, ghrelin, and melatonin in nonalcoholic steatohepatitis patients treated with melatonin

Insulin resistance, oxidative stress, and an abnormal production of adipokines and cytokines are implicated in the pathogenesis of nonalcoholic steatohepatitis (NASH). Recently, we reported a significant improvement in plasma liver enzymes among patients with NASH treated with melatonin. In this study, we investigated the effect of melatonin, administered at a dose of 10 mg/day for 28 days to 16 patients with histologically proven NASH on insulin resistance (HOMA-IR), on the plasma levels of adiponectin, leptin, ghrelin, and resistin. Additionally, plasma levels of aminotransferases and gamma glutamyltranspeptidase as well as plasma concentrations of melatonin were evaluated. Median baseline values of HOMA-IR, leptin (ng/mL), and resistin (pg/mL) in patients with NASH were significantly higher in comparison with controls: 4.90 versus 1.60, 10.70 versus 4.30, and 152 versus 91, respectively. Median adiponectin level (μg/mL) was decreased in patients compared to controls: 6.40 versus 16.25; no significant difference in ghrelin levels between patients and controls was found. After melatonin treatment, the median value of HOMA-IR was significantly reduced by 60% as compared to baseline values, whereas adiponectin, leptin, and ghrelin plasma levels rose significantly by 119%, 33%, and 20%, respectively; the difference between pre-/posttreatment in plasma resistin levels was not significant. These findings make melatonin a suitable candidate for testing in patients with NASH in the large controlled clinical trials.

Improvement of reflux symptom related quality of life after Helicobacter pylori eradication therapy

The relationship between Helicobacter pylori (H. pylori) eradication therapy and the risk of developing gastroesophageal reflux disease (GERD) is controversial. We investigated the influence of H. pylori eradication on the risk of GERD by focusing on the quality of life (QOL) and evaluating reflux symptoms. Patients with H. pylori infection were administered triple therapy for H. pylori eradication. At 3 months and 1 year after the eradication therapy, surveys were conducted to determine the health-related QOL by quality of life in reflux and dyspepsia-Japanese version, (QOLRAD-J) and the severity of GERD symptoms by Carlsson-Dent questionnaire (CDQ). Forty patients were included in the analysis. Although no significant changes of these scores were apparent 3 months after H. pylori eradication, the QOLRAD-J and CDQ scores were significantly improved after 1 year. The degree of improvement was even more marked in cases with initially low scores. In conclusion, improved GERD-related QOL and reflux symptoms were noted 1 year after H. pylori eradication therapy. In addition, the degree of improvement was more marked in cases with severe reflux symptoms.

Diabetic gastroparesis: recent insights into pathophysiology and implications for management

Delayed gastric emptying affects a substantial proportion of patients with long-standing diabetes, and when associated with symptoms and/or disordered glycemic control, affects quality of life adversely. Important clinicopathological insights have recently been gained by the systematic analysis of gastric biopsies from patients with severe diabetic gastroparesis, which may stimulate the development of new therapies in the coming decade. Experience with prokinetic therapies and treatments, such as pyloric botulinum toxin injection and gastric electrical stimulation, has established that relief of symptoms does not correlate closely with acceleration of delayed gastric emptying, and that well-designed controlled trials are essential to determine the efficacy of emerging therapies.

Ghrelin in gastrointestinal diseases

Ghrelin is an endogenous ligand of the growth hormone secretagogue receptor (GHSR). Upon binding to its receptor, Ghrelin can produce a variety of biological effects, such as promoting the release of growth hormone and maintaining energy balance. Besides, it also promotes gastrointestinal motility, increases gastric acid secretion, and is involved in the genesis of tumors. This article reviews the role of Ghrelin in gastrointestinal system disease.

Recent advances in the pathophysiology and treatment of gastroparesis

Gastroparesis is a clinical disorder characterized by upper gastrointestinal symptoms related with delayed gastric emptying of solids and liquids in the absence of mechanical obstruction. Diabetes mellitus has been the most common cause of gastroparesis and idiopathic gastroparesis also accounts for a third of all chronic cases. The most important mechanisms of gastroparesis, as understood to date, are loss of expression of neuronal nitric oxide synthase and loss of the interstitial cells of Cajal. However, the pathogenesis of gastroparesis is poorly understood. There have been several studies on specific molecules related to the pathogenesis of gastroparesis. Additionally, the Gastroparesis Clinical Research Consortium of the National Institutes of Health has achieved several promising results regarding the pathophysiology of gastroparesis. As the progress in the pathophysiology of gastroparesis has been made, a promising new drug therapy has been found. The pathophysiology and drug therapy of gastroparesis are focused in this review. Until now, the real-world medication options for treatment of gastroparesis are limited. However, it is expected to be substantially improved as the pathophysiology of gastroparesis is elucidated.