Pretreatment with obestatin reduces the severity of ischemia/reperfusion-induced acute pancreatitis in rats

Antioxidant Mechanisms Underlying the Gastroprotective Effect of Menthofuran on Experimentally Induced Gastric Lesions in Rodents

Menthofuran is a monoterpene present in various essential oils derived from species from Mentha genus, and in Brazil, those species are widely used in treating gastrointestinal and respiratory disorders. Considering the wide pharmacological potential of monoterpenes, including their antioxidant activity, this study aimed to evaluate menthofuran-gastroprotective activity, as well as the involvement of antioxidant mechanisms in this effect. The acute toxicity was evaluated according to the fixed dose method. The antiulcerogenic activity was investigated by using experimental models of gastric ulcers induced by ethanol, indomethacin, and ischemia/reperfusion in rats. The antisecretory gastric activity, the catalase activity, and the gastric wall mucus were determined in pylorus ligated rats. Gastric wall nonprotein sulfhydryl (NPSH) group content, myeloperoxidase (MPO) activity, and malondialdehyde (MDA) content were evaluated in ethanol-induced the gastric ulcer model. Menthofuran (2 g/kg) presented low acute toxicity and showed gastroprotective activity against ethanol-, indomethacin-, and ischemia/reperfusion-induced ulcers. Moreover, menthofuran presented antisecretory activity, reduced the total acidity, and increased pH of gastric secretion. On the other hand, a decrease in mucus content of gastric wall without alteration of gastric juice volume and catalase activity was observed. Interestingly, menthofuran increased NPSH levels and reduced MDA levels and MPO activity. Gastroprotective effects of menthofuran appear to be mediated, at least in part, by the NOS pathway, endogenous prostaglandins, reduced gastric juice acidity, increased concentration of the NPSH groups, and reduced lipidic peroxidation. These findings support the menthofuran as an effective gastroprotective agent, as well as the marked participation of antioxidant mechanisms in this response.

Diverse and Complementary Effects of Ghrelin and Obestatin

Ghrelin and obestatin are two “sibling proteins” encoded by the same preproghrelin gene but possess an array of diverse and complex functions. While there are ample literature documenting ghrelin’s functions, the roles of obestatin are less clear and controversial. Ghrelin and obestatin have been perceived to be antagonistic initially; however, recent studies challenge this dogma. While they have opposing effects in some systems, they function synergistically in other systems, with many functions remaining debatable. In this review, we discuss their functional relationship under three “C” categories, namely complex, complementary, and contradictory. Their functions in food intake, weight regulation, hydration, gastrointestinal motility, inflammation, and insulin secretion are complex. Their functions in pancreatic beta cells, cardiovascular, muscle, neuroprotection, cancer, and digestive system are complementary. Their functions in white adipose tissue, thermogenesis, and sleep regulation are contradictory. Overall, this review accumulates the multifaceted functions of ghrelin and obestatin under both physiological and pathological conditions, with the intent of contributing to a better understanding of these two important gut hormones.

Serum Amylase and Lipase for the Prediction of Pancreatic Injury in Critically Ill Children Admitted to the PICU

OBJECTIVES

Pancreatic injury is multifactorial and potentially devastating for critically ill children. We aimed to evaluate whether serum amylase and lipase among critically ill children could serve as an independent biomarker to predict pancreatic injury.

DESIGN

Retrospective cohort.

SETTING

PICU of a tertiary, pediatric medical center.

PATIENTS

Seventy-nine autopsies.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A group of 79 children who died of different causes were investigated by autopsy. They were divided into pancreatic injury group and pancreatic noninjury group according to autopsy findings. Data based on patients' demographics, vital signs, laboratory findings, and clinical features at admission were collected and compared. Logistic regression was used to identify predictive factors for pancreatic injury. Receiver operating characteristic curve was constructed for assessing serum amylase and serum lipase to predicting pancreatic injury. Forty-one patients (51.9%) exhibited the pathologic changes of pancreatic injury. The levels of lactate, erythrocyte sedimentation rate, alanine transaminase, aspartate transaminase, and troponin-I in the injury group were significantly higher than that in the noninjury group, whereas the level of calcium was significantly lower than that in the noninjury group (p < 0.05). Multivariable logistic regression analysis showed that serum amylase, serum lipase, and septic shock were significantly associated with the occurrence rate of pancreatic injury. The statistically significant area under the curve results were as follows: serum amylase: area under the curve = 0.731, at a cutoff value of 97.5, sensitivity = 53.7, and specificity = 81.6; and serum lipase: area under the curve = 0.727, at a cutoff value of 61.1, sensitivity = 36.6, and specificity = 92.1.

CONCLUSIONS

Serum amylase and lipase could serve as independent biomarkers to predict pancreatic injury in critically ill children.

Pretreatment with Warfarin Attenuates the Development of Ischemia/Reperfusion-Induced Acute Pancreatitis in Rats

In acute pancreatitis (AP), pancreatic damage leads to local vascular injury, manifesting as endothelial damage and activation, increased vascular permeability, leukocyte rolling, sticking and transmigration to pancreatic tissue as well as activation of coagulation. Previous studies have shown that pretreatment with heparin or acenocoumarol inhibits the development of AP. The aim of the present study was to check the impact of pretreatment with warfarin, an oral vitamin K antagonist, on the development of ischemia/reperfusion-induced AP in rats. AP was induced by pancreatic ischemia followed by reperfusion of the gland. Warfarin (90, 180 or 270 µg/kg/dose) or vehicle were administered intragastrically once a day for 7 days before induction of AP. The effect of warfarin on the severity of AP was assessed 6 h after pancreatic reperfusion. The assessment included histological, functional, and biochemical analyses. Pretreatment with warfarin given at a dose of 90 or 180 µg/kg/dose increased the international normalized ratio and reduced morphological signs of pancreatic damage such as pancreatic edema, vacuolization of acinar cells, necrosis and the number of hemorrhages. These effects were accompanied by an improvement of pancreatic blood flow and a decrease in serum level amylase, lipase, pro-inflammatory interleukin-1β and plasma level of D-dimer. In contrast, pretreatment with warfarin given at a dose of 270 µg/kg/dose led to an increase in severity of pancreatic damage and biochemical indicators of AP. In addition, this dose of warfarin resulted in deaths in some animals. Pretreatment with low doses of warfarin inhibits the development of AP induced by pancreatic ischemia followed by reperfusion.

Anti-Inflammatory and Antioxidant Activities of Medicinal Plants Used by Traditional Healers for Antiulcer Treatment

For centuries, many kinds of native plants and their products have been used for the treatment of gastric ulcers by traditional healers in Phayao province. The current study aimed to investigate the polyphenol content in some of these medicinal plants and to point out the relationship between their antioxidant capacity and anti-inflammatory activities. Six species were selected based on ethnopharmacologic considerations: Punica granatum L., Psidium guajava L., Careya arborea Roxb., Gochnatia decora (Kurz) Cabr., Shorea obtusa Wall. ex Blume, and Ficus hispida L.f. The leaves or bark of these plants were extracted with 70% ethanol and water. Anti-inflammatory and antioxidant activities of the extracts were analyzed based on nitric oxide (NO) and proinflammatory cytokine production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and through the determination of scavenging activity. The results demonstrated that the ethanol extract from P. granatum and P. guajava leaves significantly inhibited NO production by suppressing nitric oxide synthase. The extracts also inhibited tumor necrosis factor-α, interleukin-1, and interleukin-6 in terms of both mRNA and protein levels and possessed high antioxidants. These extracts were shown to contain the highest amount of polyphenols. Our study concluded that among the plants studied, P. granatum and P. guajava have the most significant anti-inflammatory and antioxidant activities and polyphenols. These plants may have the potential for use in gastric ulcer therapy due to their indicated properties. Future research should focus on the isolation of their active compounds and their in vivo biological activities. Their beneficial applications need to be warranted by such evidence.

Potential Therapeutic Effects of Gut Hormones, Ghrelin and Obestatin in Oral Mucositis

Chemotherapy and/or head and neck radiotherapy are frequently associated with oral mucositis. Oral pain, odynophagia and dysphagia, opioid use, weight loss, dehydration, systemic infection, hospitalization and introduction of a feeding tube should be mentioned as the main determinated effect of oral mucositis. Oral mucositis leads to a decreased quality of life and an increase in treatment costs. Moreover, oral mucositis is a life-threatening disease. In addition to its own direct life-threatening consequences, it can also lead to a reduced survival due to the discontinuation or dose reduction of anti-neoplasm therapy. There are numerous strategies for the prevention or treatment of oral mucositis; however, their effectiveness is limited and does not correspond to expectations. This review is focused on the ghrelin and obestatin as potentially useful candidates for the prevention and treatment of chemo- or/and radiotherapy-induced oral mucositis.

Treatment with Obestatin-A Ghrelin Gene-Encoded Peptide-Reduces the Severity of Experimental Colitis Evoked by Trinitrobenzene Sulfonic Acid

Obestatin is a 23-amino acid peptide derived from proghrelin, a common prohormone for ghrelin and obestatin. Previous studies showed that obestatin exhibited some protective and therapeutic effects in the gut. The aim of our presented study was to examine the effect of treatment with obestatin on trinitrobenzene sulfonic acid (TNBS)-induced colitis. In rats anesthetized with ketamine, colitis was induced through intrarectal administration of 25 mg of 2,4,6-trinitrobenzene sulfonic acid (TNBS). Obestatin was administered intraperitoneally at doses of 4, 8, or 16 nmol/kg, twice per day for four consecutive days. The first dose of obestatin was given one day before the induction of colitis, and the last one was given two days after administration of TNBS. Fourteen days after the induction of colitis, rats were anesthetized again with ketamine, and the severity of colitis was determined. The administration of obestatin had no effect on the parameters tested in rats without the induction of colitis. In rats with colitis, administration of obestatin at doses of 8 or 16 nmol/kg reduced the area of colonic damage, and improved mucosal blood flow in the colon. These effects were accompanied by a reduction in the colitis-evoked increase in the level of blood leukocytes, and mucosal concentration of pro-inflammatory interleukin-1β. Moreover, obestatin administered at doses of 8 or 16 nmol/kg reduced histological signs of colonic damage. The administration of obestatin at a dose of 4 nmol/kg failed to significantly affect the parameters tested. Overall, treatment with obestatin reduced the severity of TNBS-induced colitis in rats. This effect was associated with an improvement in mucosal blood flow in the colon, and a decrease in local and systemic inflammatory processes.

Pretreatment with obestatin inhibits the development of acetic acid-induced colitis in rats

INTRODUCTION

Obestatin is a 23-amino acid peptide derived from proghrelin, a common prohormone for ghrelin and obestatin. Previous studies have shown that obestatin exhibits some protective and therapeutic effects in the pancreas and stomach. The aim of this study was to examine the effect of pretreatment with obestatin on the development of acetic acid-induced colitis.

MATERIAL AND METHODS

Studies were performed on Wistar rats. Before induction of colitis, rats were treated intraperitoneally with saline or obestatin, administered twice at a dose of 4, 8 or 16 nmol/kg/dose. The first dose of saline or obestatin was administered 8 h before the induction of colitis, the second one 7 h after the first dose. Colitis was induced by enema with 1 ml of 4% acetic acid solution. The severity of colitis was assessed 1 or 24 h after administration of enema.

RESULTS

Pretreatment with obestatin administered at a dose of 8 or 16 nmol/kg/dose significantly reduced the area of mucosal damage evoked by enema with acetic acid (p < 0.05). This effect was accompanied by an improvement of mucosal blood flow and DNA synthesis in the colon. Moreover, obestatin administered at a dose of 8 or 16 nmol/kg/dose significantly reduced mucosal concentration of IL-1β and activity of myeloperoxidase (p < 0.05).

CONCLUSIONS

Pretreatment with obestatin exhibited a protective effect in the colon, leading to a reduction of colonic damage in acetic acid-induced colitis. This effect was associated with an improvement of mucosal blood flow, an increase in mucosal cell proliferation, and a decrease in local inflammation.

Dietary Polysaccharide from Enteromorpha Clathrata Modulates Gut Microbiota and Promotes the Growth of Akkermansia muciniphila, Bifidobacterium spp. and Lactobacillus spp

Recently, accumulating evidence has suggested that Enteromorpha clathrata polysaccharide (ECP) could contribute to the treatment of diseases. However, as a promising candidate for marine drug development, although ECP has been extensively studied, less consideration has been given to exploring its effect on gut microbiota. In this light, given the critical role of gut microbiota in health and disease, we investigated here the effect of ECP on gut microbiota using 16S rRNA high-throughput sequencing. As revealed by bioinformatic analyses, ECP considerably changed the structure of the gut microbiota and significantly promoted the growth of probiotic bacteria in C57BL/6J mice. However, interestingly, ECP exerted different effects on male and female microbiota. In females, ECP increased the abundances of Bifidobacterium spp. and Akkermansia muciniphila, a next-generation probiotic bacterium, whereas in males, ECP increased the population of Lactobacillus spp. Moreover, by shaping a more balanced structure of the microbiota, ECP remarkably reduced the antigen load from the gut in females. Altogether, our study demonstrates for the first time a prebiotic effect of ECP on gut microbiota and forms the basis for the development of ECP as a novel gut microbiota modulator for health promotion and disease management.

Melatonin and its metabolite N1-acetyl-N2-formyl-5-methoxykynuramine (afmk) enhance chemosensitivity to gemcitabine in pancreatic carcinoma cells (PANC-1)

BACKGROUND

Gemcitabine is a standard chemotherapeutic agent for patients suffering from pancreatic cancer. However, the applied therapy is not effective due to the resistance of tumor cells to cytostatics, caused by inefficiency of the apoptotic mechanisms. Herein, we present the hypothesis that melatonin and its metabolite N¹-acetyl-N²-formyl-5-methoxykynuramine (AFMK) modify the effect of gemcitabine on PANC-1 cells and that this phenomenon is dependent on the modulation of apoptosis.

METHODS

PANC-1 cells have been incubated with melatonin, AFMK or gemcitabine alone or in combination to determine the cytotoxity and proliferative effects. In subsequent part of the study, cells were harvested, the proteins were isolated and analyzed employing immunoprecipitation/immunoblotting.

RESULTS

Incubation of PANC-1 cells with gemcitabine resulted in upregulation of pro-apoptotic bax and caspases proteins expression, downregulation of anti-apoptotic Bcl-2, heat shock proteins (HSPs) and modulation of cellular inhibitors of apoptosis (IAPs). Both melatonin and AFMK administered to PANC-1 in combination with gemcitabine inhibited the production of HSP70 and cIAP-2 as compared to the results obtained with gemcitabine alone. These changes were accompanied by upregulation of Bax/Bcl-2 ratio and reduction of procaspases-9 and -3 abundance, followed by an increase in the formation of active caspase of PANC-1 cells with combination of gemcitabine plus low doses of melatonin or AFMK led to enhanced cytotoxicity and resulted in the inhibition of PANC-1 cells growth as compared to effects of gemcitabine alone.

CONCLUSION

Melatonin and AFMK could improve the anti-tumor effect of gemcitabine in PANC-1 cells presumably through the modulation of apoptotic pathway.

Biochemical properties and biological actions of obestatin and its relevence in type 2 diabetes

Obestatin was initially discovered in rat stomach extract, and although it is principally produced in the gastric mucosa, it can be found throughout the gastrointestinal tract. This 23-amino acid C-terminally amidated peptide is derived from preproghrelin and has been ascribed a wide range of metabolic effects relevant to type 2 diabetes. Obestatin reportedly inhibits gastrointestinal motility, reduces food intake and lowers body weight and improves lipid metabolism. Furthermore, it appears to exert actions on the pancreatic β-cell, most notably increasing β-cell mass and upregulating genes associated with insulin production and β-cell regeneration, with relevance to type 2 diabetes. It is becoming evident that obestatin also exerts pleiotropic effects on the cardiovascular system, possibly modulating blood pressure, endothelial function and triggering cardioprotective mechanisms, which may be important in determining cardiovascular outcomes in type 2 diabetes. Furthermore, it seems that like other gut peptides obestatin has neuroprotective properties. This review examines the biochemical properties of the obestatin peptide (its structure, sequence, stability and distribution) and the candidate receptors through which it may act. It provides a balanced examination of the reported pancreatic and extrapancreatic actions of obestatin and evaluates its potential relevance with respect to diabetes therapy, together with discussion of direct evidence linking alterations in obestatin signalling with obesity/diabetes and other diseases.

Obestatin prevents H2O2-induced damage through activation of TrkB in RGC-5 cells

BACKGROUD

In the early stage of diabetic retinopathy, the damage of retinal ganglion cells already exists, promoting the development of the disease. The aim of this study was to investigate the protective role and the mechanisms of obestatin against H₂O₂-induced damage in RGC-5 cells.

METHODS

RGC-5 cells were incubated with various concentrations of obestatin for 24h before H₂O₂ added. The survival rates of RGC-5 were measured by MTT assay. The expression of apoptosis-related proteins and TrkB pathway-related proteins were detected by Western blot analysis.

RESULTS

Our data showed that H₂O₂ evidently decreased the survival rate of RGC-5 cells. However, obestatin pretreatment reversed the decreased activity. Moreover, obestatin effectively increased the expression of Bcl-2 and decreased the expression of Bax. In addition, obestatin potentially plays a role in protecting RGC-5 by activating of TrkB. Obestatin notablely increased the phosphorylation of TrkB, AKT and ERK1/2. All these effects of obestatin can be inhibited by GLP-1R antagonist exendin (9-39).

CONCLUSIONS

Obestatin prevents H₂O₂-induced damage in RGC-5 cells by activating TrkB pathway. Moreover, GLP-1R is closely related to the function of obestatin in RGC-5 cells.

Ghrelin protects the heart against ischemia/reperfusion injury via inhibition of TLR4/NLRP3 inflammasome pathway

AIMS

The aim of this study was to investigate the cardioprotective effects of ghrelin against myocardial ischemia/reperfusion (I/R) injury and the underlying mechanism.

MAIN METHODS

Sprague-Dawley rats were randomized into Sham, I/R and I/R+ghrelin groups. After 30 minutes ischemia, ghrelin (8nmol/kg) was injected intraperitoneally at the time of reperfusion in the I/R+ghrelin group. Then hemodynamic parameters were observed at 24h after reperfusion.

KEY FINDINGS

Ghrelin exhibited dramatic improvement in cardiac functions, as manifested by increased LVSP and ±dP/dt_max and decreased LVDP. At 24h after reperfusion, ghrelin significantly attenuated the myocardial infarction area and apoptosis, accompanied with a decrease in the levels of the myocyte injury marker enzymes. Oxidative stress injury and inflammatory response were also relieved by ghrelin. Western blot showed that the expression of TLR4, NLRP3, and caspase-1 were obviously increased in I/R group, while ghrelin significantly inhibited the I/R-induced TLR4, NLRP3, and caspase-1 expression. Ghrelin could inhibit the increased protein levels of NLRP3, caspase-1, and IL-1β induced by lipopolysacharide in primary cultured cardiomyocytes of neonatal rats.

SIGNIFICANCE

Ghrelin protected the heart against I/R injury by inhibiting oxidative stress and inflammation via TLR4/NLRP3 signaling pathway. Our results might provide new strategy and target for treatment of myocardial ischemia/reperfusion injury.

Obestatin Plays Beneficial Role in Cardiomyocyte Injury Induced by Ischemia-Reperfusion In Vivo and In Vitro

BACKGROUND Obestatin, primarily recognized as a peptide within the gastrointestinal system, has been shown to benefit the cardiovascular system. We designed this experiment to study the protective role and underlying mechanism of obestatin against ischemia-reperfusion(I/R) injury in myocardial cells. MATERIAL AND METHODS In an In vivo experiment, LAD was ligated for 0.5 h and then opened for reperfusion with obestatin for 24 h. Then, the infarction area was shown with TTC staining, and inflammation factors in serum were analyzed by qRT-PCR. In primary cultured cardiomyocytes, we measured the level of LDH, MDA, GSH, and SOD. Finally, we assessed cells apoptosis using flow cytometry and detected the concentrations of caspase-3, Bax, and Bcl-2 using Western blot analysis. RESULTS TTC staining showed that in the 3 obestatin groups, the infarct area became smaller with the increase of obestatin concentration. Obestatin also inhibited LDH expression in rat serum and decreased mRNA levels of TNF-α, IL-6, ICAM-1, and iNOS in rat cardiomyocytes after reperfusion. In primary cultured cardiomyocytes, obestatin decreased LDH content and increased GSH level after I/R injury. Obestatin was also found to antagonize the apoptosis of cardiomyocytes in a dose-dependent manner. Western blot analysis showed that obestatin downregulated the expression of caspase-3 and Bax and upregulated the expression of Bcl-2. CONCLUSIONS Obestatin can protect cardiomyocyte from I/R-induced injury in vitro and in vivo. This beneficial effect is closely related with its properties of anti-inflammation, anti-cytotoxicity, and anti-apoptosis. The protective effect of obestatin might be associated with activation of Bcl-2 and inhibition of caspase-3 and Bax.

Ghrelin mitigates β-cell mass loss during insulitis in an animal model of autoimmune diabetes mellitus, the BioBreeding/Worcester rat

BACKGROUND

Ghrelin is a peptide hormone with pleiotropic effects. It stimulates cell proliferation and inhibits apoptosis-mediated cell death. It prevents diabetes mellitus in several models of chemical, surgical and biological toxic insults to pancreas in both in vivo and in vitro models and promotes glucose-stimulated insulin secretion under cytotoxic conditions. It has not yet been tested in vivo in an autoimmune model of diabetes with a persistent insult to the β-cell. Given the immunomodulating effects of ghrelin and its trophic effects on β-cells, we hypothesized that ghrelin treatment during the early stages of insulitis would delay diabetes onset.

METHODS

BioBreeding/Worcester male rats received ghrelin (10 ng/kg/day) before insulitis development. Glucose metabolism was characterized by glucose and insulin tolerance tests. β-cell mass, islet area, islet number, β-cell clusters, proliferation and apoptosis and degree of insulitis were analysed by histomorphometry. A Kaplan-Meier survival curve was plotted and analysed applying the log-rank (Mantel-Cox) test.

RESULTS

Ghrelin treatment significantly reduced the probability of developing diabetes in our model (p < 0.0001). It decreased islet infiltration and partially prevented β-cell mass loss, enabling the maintenance of β-cell neogenesis and proliferation rates. Furthermore, ghrelin treatment did not induce any metabolic perturbations.

CONCLUSIONS

These findings support the hypothesis that ghrelin delays the development of autoimmune diabetes by attenuating insulitis and supporting β-cell mass.

GENERAL SIGNIFICANCE

Ghrelin promotes β-cell viability and function through diverse mechanisms that may have significant implications for diabetes prevention, therapy and also transplant success of both islets and complete pancreas. Copyright © 2016 John Wiley & Sons, Ltd.

Protective Effect of Pretreatment with Acenocoumarol in Cerulein-Induced Acute Pancreatitis

Coagulation is recognized as a key player in inflammatory and autoimmune diseases. The aim of the current research was to examine the effect of pretreatment with acenocoumarol on the development of acute pancreatitis (AP) evoked by cerulein. Methods: AP was induced in rats by cerulein administered intraperitoneally. Acenocoumarol (50, 100 or 150 µg/kg/dose/day) or saline were given once daily for seven days before AP induction. Results: In rats with AP, pretreatment with acenocoumarol administered at the dose of 50 or 100 µg/kg/dose/day improved pancreatic histology, reducing the degree of edema and inflammatory infiltration, and vacuolization of acinar cells. Moreover, pretreatment with acenocoumarol given at the dose of 50 or 100 µg/kg/dose/day reduced the AP-evoked increase in pancreatic weight, serum activity of amylase and lipase, and serum concentration of pro-inflammatory interleukin-1β, as well as ameliorated pancreatic DNA synthesis and pancreatic blood flow. In contrast, acenocoumarol given at the dose of 150 μg/kg/dose did not exhibit any protective effect against cerulein-induced pancreatitis. Conclusion: Low doses of acenocoumarol, given before induction of AP by cerulein, inhibit the development of that inflammation.

Obestatin as a key regulator of metabolism and cardiovascular function with emerging therapeutic potential for diabetes

Obestatin is a 23-amino acid C-terminally amidated gastrointestinal peptide derived from preproghrelin and which forms an α helix. Although obestatin has a short biological half-life and is rapidly degraded, it is proposed to exert wide-ranging pathophysiological actions. Whilst the precise nature of many of its effects is unclear, accumulating evidence supports positive actions on both metabolism and cardiovascular function. For example, obestatin has been reported to inhibit food and water intake, body weight gain and gastrointestinal motility and also to mediate promotion of cell survival and prevention of apoptosis. Obestatin-induced increases in beta cell mass, enhanced adipogenesis and improved lipid metabolism have been noted along with up-regulation of genes associated with beta cell regeneration, insulin production and adipogenesis. Furthermore, human circulating obestatin levels generally demonstrate an inverse association with obesity and diabetes, whilst the peptide has been shown to confer protective metabolic effects in experimental diabetes, suggesting that it may hold therapeutic potential in this setting. Obestatin also appears to be involved in blood pressure regulation and to exert beneficial effects on endothelial function, with experimental studies indicating that it may also promote cardioprotective actions against, for example, ischaemia-reperfusion injury. This review will present a critical appraisal of the expanding obestatin research area and discuss the emerging therapeutic potential of this peptide for both metabolic and cardiovascular complications of diabetes.

Obestatin Accelerates the Healing of Acetic Acid-Induced Colitis in Rats

Obestatin, a 23-amino acid peptide derived from the proghrelin, has been shown to exhibit some protective and therapeutic effects in the gut. The aim of present study was to determine the effect of obestatin administration on the course of acetic acid-induced colitis in rats. Materials and Methods. Studies have been performed on male Wistar rats. Colitis was induced by a rectal enema with 3.5% acetic acid solution. Obestatin was administered intraperitoneally twice a day at a dose of 8 nmol/kg, starting 24 h after the induction of colitis. Seven or 14 days after the induction of colitis, the healing rate of the colon was evaluated. Results. Treatment with obestatin after induction of colitis accelerated the healing of colonic wall damage and this effect was associated with a decrease in the colitis-evoked increase in mucosal activity of myeloperoxidase and content of interleukin-1β. Moreover, obestatin administration significantly reversed the colitis-evoked decrease in mucosal blood flow and DNA synthesis. Conclusion. Administration of exogenous obestatin exhibits therapeutic effects in the course of acetic acid-induced colitis and this effect is related, at least in part, to the obestatin-evoked anti-inflammatory effect, an improvement of local blood flow, and an increase in cell proliferation in colonic mucosa.

Obestatin Accelerates the Recovery in the Course of Ischemia/Reperfusion-Induced Acute Pancreatitis in Rats

Objective

Several previous studies have shown that obestatin exhibits protective and regenerative effects in some organs including the stomach, kidney, and the brain. In the pancreas, pretreatment with obestatin inhibits the development of cerulein-induced acute pancreatitis, and promotes survival of pancreatic beta cells and human islets. However, no studies investigated the effect of obestatin administration following the onset of experimental acute pancreatitis.

Aim

The aim of this study was to evaluate the impact of obestatin therapy in the course of ischemia/reperfusion-induced pancreatitis. Moreover, we tested the influence of ischemia/reperfusion-induced acute pancreatitis and administration of obestatin on daily food intake and pancreatic exocrine secretion.

Methods

Acute pancreatitis was induced by pancreatic ischemia followed by reperfusion of the pancreas. Obestatin (8nmol/kg/dose) was administered intraperitoneally twice a day, starting 24 hours after the beginning of reperfusion. The effect of obestatin in the course of necrotizing pancreatitis was assessed between 2 and 14 days, and included histological, functional, and biochemical analyses. Secretory studies were performed on the third day after sham-operation or induction of acute pancreatitis in conscious rats equipped with chronic pancreatic fistula.

Results

Treatment with obestatin ameliorated morphological signs of pancreatic damage including edema, vacuolization of acinar cells, hemorrhages, acinar necrosis, and leukocyte infiltration of the gland, and led to earlier pancreatic regeneration. Structural changes were accompanied by biochemical and functional improvements manifested by accelerated normalization of interleukin-1β level and activity of myeloperoxidase and lipase, attenuation of the decrease in pancreatic DNA synthesis, and by an improvement of pancreatic blood flow. Induction of acute pancreatitis by pancreatic ischemia followed by reperfusion significantly decreased daily food intake and pancreatic exocrine secretion. Administration of obestatin at doses used was without significant effect with regard to daily food intake or pancreatic exocrine secretion in sham-operated rats, as well as in rats with acute pancreatitis. On the other hand, obestatin abolished a statistical significance of difference in food intake between animals with AP and control animals without pancreatic fistula and induction of AP.

Conclusion

Treatment with the exogenous obestatin reduces severity of ischemia/reperfusion-induced acute pancreatitis and accelerates recovery in this disease. The involved mechanisms are likely to be multifactorial, and are mediated, at least in part, by anti-inflammatory properties of obestatin.