Oxyntomodulin analog and exendin-4 derivative lower plasma glucose in cattle

The present study was undertaken with the aim of examining whether and how exendin-4 (1-3) fragment, ie, Ex-4 (1-3) fragment, contributes to the regulation of glucose. An analog of oxyntomodulin (OXM) ([Gly², Glu³]-OXM), a glucagon analog ([Gly², Glu³]-glucagon), and two derivatives of Ex-4 (glucandin and [Gly², Glu³]-glucandin) were synthesized by substituting with Gly², Glu³ at the N-terminuses of OXM and glucagon and/or by attaching Ex-4 (30-39) amide at the C-terminus of glucagon. Effects of these peptides on plasma insulin and glucose concentrations were investigated in cattle by conducting 3 in vivo experiments. In all 3 experiments, 0.1% BSA saline was injected as a control. In experiment 1, glucandin (amino acid sequence was glucagon [1-29]-Ex-4 [30-39] amide) and [Gly², Glu³]-glucandin were injected at the dose rates of 5 μg/kg BW in 4-mo-old Holstein steers. Results showed that glucoregulatory effects of glucandin were similar to those of glucagon. [Gly², Glu³]-glucandin stimulated insulin secretion at 2 to 10 min and lowered glucose concentrations at 15 to 75 min. Experiment 2 was carried out to better understand the glucose-lowering potency of [Gly², Glu³]-glucandin, in comparison with Ex-4 and glucagon-like peptide-1 (GLP-1), using 4.5-mo-old Holstein steers. [Gly², Glu³]-glucandin was injected at dose rates of 0.3 μg/kg BW, 1.0 μg/kg BW, 3.2 μg/kg BW, and 6.4 μg/kg BW. Ex-4 and GLP-1 were injected at dose rates of 0.3 μg/kg BW. Results showed that the insulinotropic and glucose-lowering effects of [Gly², Glu³]-glucandin were not as potent as for Ex-4 and GLP-1, and the minimum effective dose of [Gly², Glu³]-glucandin to regulate plasma glucose concentrations was 3.2 μg/kg BW. In experiment 3, [Gly², Glu³]-OXM and [Gly², Glu³]-glucagon were injected at dose rates of 5 μg/kg BW in 5-mo-old Holstein steers. Both [Gly², Glu³]-OXM and [Gly², Glu³]-glucagon increased insulin concentration. [Gly², Glu³]-OXM potently lowered plasma glucose, but [Gly², Glu³]-glucagon did not change it. In summary, our findings clearly demonstrate that Ex-4 (1-3) fragment contributes to the regulation of glucose. [Gly², Glu³]-OXM and [Gly², Glu³]-glucandin are insulinotropic and glucose-lowering peptides. It was of interest that the substitution of the first 3 amino acids of OXM with Ex-4 (1-3) could reverse the upregulation of glucose by OXM into downregulation of glucose. In lowering glycemia, [Gly², Glu³]-OXM seemed almost as effective as Ex-4, and [Gly², Glu³]-glucandin was less profound than Ex-4. These findings contributed new insights into the hormonal regulation of glucose in ruminants. The action of [Gly², Glu³]-OXM and [Gly², Glu³]-glucandin might provide an advantage in glycemic control of insulin resistance in cattle and humans.

Insulinotropic action of bombesin-like peptides mediated by gastrin-releasing peptide receptors in steers

The present study characterizes the receptor that mediates the insulinotropic action of bombesin-like peptides (BLP) in ruminants. Eight Holstein steers were randomly and intravenously injected with synthetic bovine gastrin-releasing peptide (GRP; 0.9 nmol/kg BW), neuromedin B (NMB; 0.9 nmol/kg BW), or neuromedin C (NMC; 0.9 nmol/kg BW), each alone or combined with the antagonist of GRP receptors N-acetyl-GRP-OCHCH (N-GRP-EE; 22.5 nmol/kg BW) or the antagonist of GH secretagogue receptor type 1a (GHS-R1a) [D-Lys]-GHRP-6 (21.5 nmol/kg BW). Blood samples were collected at -10, 0 (just before injection), 5, 10, 15, 20, 30, 45, 60, 75, and 90 min relative to injection time. Levels of injected peptides, insulin, and glucose in plasma were analyzed. Results showed that the peak of insulin levels was seen at 5 min after injection of NMC or GRP. Plasma glucose was observed in 2 phases; a significant rise followed a remarkable fall after NMC or GRP administration compared with injection of the vehicle ( < 0.05). On a same molar basis, effects of GRP on insulin and glucose were more potent than those of NMC ( < 0.05). The NMC-induced changes of insulin and glucose were completely blocked by N-GRP-EE, but [D-Lys]-GHRP-6 did not block any of these changes. Administration of NMB or N-GRP-EE alone did not change the circulating levels of insulin or glucose during any of the sampling time points ( > 0.05). These results indicated that the insulinotropic action of BLP is mediated by GRP receptors but not through a ghrelin/GHS-R1a pathway and that BLP may be involved in the regulation of glucose homeostasis in ruminants.

Oxyntomodulin attenuates exendin-4-induced hypoglycemia in cattle

Oxyntomodulin (OXM), glucagon, glucagon-like peptide-1 (GLP-1), and exendin-4 (Ex-4) are peptide hormones that regulate glucose homeostasis in monogastric and ruminant animals. Recently, we reported that the insulin-releasing effects of OXM and glucagon in cattle are mediated through both GLP-1 and glucagon receptors. The purpose of this study was to examine the mechanisms of the glucoregulatory actions induced by Ex-4, GLP-1, OXM, and glucagon and the interrelationships among these hormones in cattle. Two experiments were performed in Holstein cattle. In Experiment 1, we initially assessed the effects of intravenous (iv) bolus injection of 0, 0.25, 1, and 2 μg/kg body weight (BW) of Ex-4, GLP-1, and OXM on insulin and glucose concentrations in 3-mo-old intact male Holstein calves. In Experiment 2, we studied insulin and glucose responses to iv coinjection of 0.25 μg of Ex-4 or GLP-1/kg BW with 2 μg of OXM or glucagon/kg BW in 4-mo-old Holstein steers. Administration of peptides and blood sampling were done via a jugular catheter. Plasma was separated and the concentrations of peptides and glucose in plasma were analyzed using radioimmunoassay and enzymatic methods, respectively. Results showed that the potent glucoregulatory action of Ex-4 in 4-mo-old steers was delayed and attenuated when Ex-4 was coinjected with OXM. The decline in plasma glucose concentrations began at 5 min in the Ex-4-injected group (P < 0.05) vs 15 min in the Ex-4 + OXM-injected group (P < 0.05). Plasma concentrations of glucose at 30 min were reduced 26% from basal concentrations in the Ex-4-injected group and 13% in the Ex-4 + OXM-injected group (P < 0.001). Results also showed that the glucose concentrations initially increased in the Ex-4 + glucagon-treated group, but declined to a relatively hypoglycemic condition by 90 to 120 min. In contrast, the glucose concentrations at specific time points between the GLP-1 + OXM-injected group and the OXM-injected group did not differ. Similarly, the glucose concentrations in the GLP-1 + glucagon-injected group did not differ from those in the glucagon-injected group. Because OXM and glucagon mediate glucose concentrations via the glucagon receptor, it is suggested that the potent glucose-lowering action of Ex-4 might include the glucagon receptor antagonistic action of Ex-4.

Glucagon-like peptide-1 inhibits insulinotropic effects of oxyntomodulin and glucagon in cattle

Oxyntomodulin (OXM), glucagon, and glucagon-like peptide-1 (GLP-1), peptide hormones derived from the glucagon gene, play an important role in glucose homeostasis. The insulinotropic action of these three homologous peptides has been well documented in monogastric animals. However, information on the relationships among these peptides in insulin-releasing action, specifically in ruminants, is still insufficient. In this regard, we carried out two experiments in cattle. In experiment 1, effects of glucagon and GLP-1 on plasma insulin and glucose were investigated in 10-mo-old Holstein steers (347 ± 8 kg, n = 8) under normoglycemic conditions. Peptides were administered intravenously at dose rates of 0.12, 0.25, 0.50, and 1.25 nmol/kg body weight (BW). In experiment 2, the relationships among OXM, glucagon, and GLP-1 in the insulinotropic and glucoregulatory actions were elucidated in 3-mo-old Holstein steers (94 ± 2 kg, n = 8) using agonist-antagonist strategy. In agonist strategy, these three peptides were administered alone or coadministered at dose rates of 10 μg of OXM/kg BW, 4 μg of glucagon/kg BW, and 2 μg of GLP-1/kg BW. In antagonist strategy, 2 μg of each peptide was administered alone or in combination with 10 μg of [des His1, des Phe6, Glu9] glucagon amide (a glucagon receptor antagonist) or exendin-4 (5-39) amide (a GLP-1 receptor antagonist). Our results showed that OXM, glucagon, and GLP-1 had insulinotropic actions in ruminants under normoglycemic conditions. Our results also showed that the insulin-releasing effects of OXM and glucagon were mediated through both GLP-1 receptors (GLP-1R) and glucagon receptors. These insulinotropic effects of OXM and glucagon through GLP-1R were inhibited by GLP-1. Our findings expand the relationships among OXM, glucagon, and GLP-1 in the insulinotropic and glucoregulatory actions.

Ghrelin and leptin did not improve meiotic maturation of porcine oocytes cultured in vitro

To improve culture system for in vitro maturation (IVM) of porcine oocytes, ghrelin, leptin or growth hormone (GH), at concentration of 0, 0.5, 5, 50 and 500 ng/ml were added to the porcine follicular fluid (pFF)-supplemented medium NCSU23, and their effects on the maturation and cytoskeletal distribution of the oocytes with or without cumulus cells were compared. In the cumulus-denuded oocytes, no significant changes were noted in the maturation rate by different hormone treatments due to a marked decline in the controls. Maturation of the cumulus intact oocytes was moderately interfered by ghrelin (0.5-50 ng/ml, p < 0.01), but not significantly affected by leptin and GH. Distribution density of the cytoplasmic microtubules was decreased significantly by addition of ghrelin (by approximately 30% in 50-500 ng/ml, p < 0.01), whereas no remarkable effect was noted by leptin supplementation. High concentration (500 ng/ml) of ghrelin or leptin decreased significantly the cytoplasmic microfilaments in density (by 43% and 38%, p < 0.01, respectively). GH did not affect cytoskeletal distribution. The results suggest, in the culture system using pFF-supplemented medium that (i) ghrelin may have some inhibitory effect on the organization of microtubules and microfilaments, probably being a factor in lowered maturation rate and (ii) the addition of higher concentration of leptin may decrease microfilaments in density with no effect on meiotic maturation of the porcine oocytes.

Oxyntomodulin increases the concentrations of insulin and glucose in plasma but does not affect ghrelin secretion in Holstein cattle under normal physiological conditions

Ghrelin, the natural ligand of the growth hormone secretagogue receptor (GHS-R1a), has been shown to stimulate growth hormone (GH) secretion. Regulation of ghrelin secretion in ruminants is not well studied. We investigated the effects of oxyntomodulin (OXM) and secretin on the secretions of ghrelin, insulin, glucagon, glucose, and nonesterified fatty acids (NEFA) in pre-ruminants (5 wk old) and ruminants (10 wk old) under normal physiological (feeding) conditions. Eight male Holstein calves (pre-ruminants: 52 +/- 1 kg body weight [BW]; and ruminants: 85 +/- 1 kg BW) were injected intravenously with 30 microg of OXM/kg BW, 50 microg of secretin/kg BW, and vehicle (0.1% bovine serum albumin [BSA] in saline as a control) in random order. Blood samples were collected, and plasma hormones and metabolites were analyzed using a double-antibody radioimmunoassay system and commercially available kits, respectively. We found that OXM increased the concentrations of insulin and glucose but did not affect the concentrations of ghrelin in both pre-ruminants and ruminants and that there was no effect of secretin on the concentrations of ghrelin, insulin, and glucose in these calves. We also investigated the dose-response effects of OXM on the secretion of insulin and glucose in 8 Holstein steers (401 +/- 1 d old, 398 +/- 10 kg BW). We found that OXM increased the concentrations of insulin and glucose even at physiological plasma concentrations, with a minimum effective dose of 0.4 microg/kg for the promotion of glucose secretion and 2 microg/kg for the stimulation of insulin secretion. These findings suggest that OXM takes part in glucose metabolism in ruminants.

Endogenous ghrelin released in response to endothelin stimulates growth hormone secretion in cattle

The purpose of this study was to evaluate whether circulating ghrelin and growth hormone (GH) concentrations in cattle are regulated by endothelin-1 (ET-1), endothelin-3 (ET-3), and secretin. Six Holstein steers (242+/-1 d old, 280.5+/-4.4 kg body weight [BW]; mean+/-SEM) were allocated randomly in an incomplete Latin square design to receive each of 4 treatment compounds (vehicle, ET-1, ET-3, and secretin) with 1-d intervals between successive treatments. The treatment compounds were injected intravenously via a catheter inserted into the external jugular vein of each steer. Blood was sampled from the indwelling catheter at -30, -15, 0, 5, 10, 15, 20, 30, 45, 60, 90, 120, 150, and 180 min. Plasma ghrelin and GH responses to the treatment compounds were measured by a double-antibody radioimmunoassay system. Data were analyzed by using a MIXED procedure of SAS, version 9.1. Plasma acyl ghrelin, total ghrelin, and GH concentrations were increased by both ET-1 and ET-3 injection (ET-1 injection: 311+/-15 pg/mL vs 245+/-15 pg/mL, 2.4+/-0.2 ng/mL vs 1.61+/-0.05 ng/mL, 4.73+/-0.92 ng/mL vs 1.17+/-0.09 ng/mL for acyl ghrelin, total ghrelin, and GH, respectively; ET-3 injection: 337+/-27 pg/mL vs 245+/-15 pg/mL, 2.6+/-0.1 ng/mL vs 1.61+/-0.05 ng/mL, 5.56+/-0.97 ng/mL vs 1.17+/-0.09 ng/mL for acyl ghrelin, total ghrelin, and GH, respectively; P<0.01). Ghrelin and GH concentrations were not changed by secretin injection throughout the experimental periods. These results indicate that ET-1 and ET-3 stimulate ghrelin and GH secretion in cattle and demonstrate for the first time that endogenous ghrelin released in response to endothelin injection stimulates GH secretion in vivo in cattle.

Interaction between salsolinol (SAL) and thyrotropin-releasing hormone (TRH) or dopamine (DA) on the secretion of prolactin in ruminants

We have recently demonstrated that salsolinol (SAL), a dopamine (DA)-derived compound, is present in the posterior pituitary gland and is able to stimulate the release of prolactin (PRL) in ruminants. The aim of the present study was to clarify the effect that the interaction of SAL with thyrotropin-releasing hormone (TRH) or DA has on the secretion of PRL in ruminants. A single intravenous (i.v.) injection of SAL (5mg/kg body weight (b.w.)), TRH (1microg/kg b.w.), and SAL plus TRH significantly stimulated the release of PRL in goats (P<0.05). The cumulative response curve (area under the curve: AUC) during 120min was 1.53 and 1.47 times greater after the injection of SAL plus TRH than either SAL or TRH alone, respectively (P<0.05). A single i.v. injection of sulpiride (a DA receptor antagonist, 0.1mg/kg b.w.), sulpiride plus SAL (5mg/kg b.w.), and sulpiride plus TRH (1microg/kg b.w.) significantly stimulated the release of PRL in goats (P<0.05). The AUC of PRL during 120min was 2.12 and 1.78 times greater after the injection of sulpiride plus TRH than either sulpiride alone or sulpiride plus SAL, respectively (P<0.05). In cultured bovine anterior pituitary (AP) cells, SAL (10(-6)M), TRH (10(-8)M), and SAL plus TRH significantly increased the release of PRL (P<0.05), but the additive effect of SAL and TRH detected in vivo was not observed in vitro. In contrast, DA (10(-6)M) inhibited the TRH-, as well as SAL-induced PRL release in vitro. All together, these results clearly show that SAL can stimulate the release of PRL in ruminants. Furthermore, they also demonstrate that the additive effect of SAL and TRH on the release of PRL detected in vivo may not be mediated at the level of the AP, but that DA can overcome their releasing activity both in vivo and in vitro, confirming the dominant role of DA in the inhibitory regulation of PRL secretion in ruminants.

Rabeprazole-based eradication therapy for Helicobacter pylori: a large-scale study in Japan

BACKGROUND

Large-scale studies of rabeprazole-based Helicobacter pylori eradication therapy have not been reported in Japan.

AIMS

To evaluate H. pylori eradication by rabeprazole-based therapy with reference to antibiotic susceptibility, CYP2C19 genotype, and rabeprazole and clarithromycin dosages.

METHODS

From 35 centres 479 H. pylori-positive patients with gastric or duodenal ulcer were randomized to four treatment groups: Group 1 (10 mg rabeprazole + 750 mg amoxicillin + 200 mg clarithromycin twice daily for 7 days); Group 2 (10 mg, 750 mg, 400 mg); Group 3 (20 mg, 750 mg, 200 mg) and Group 4 (20 mg, 750 mg, 400 mg).

RESULTS

Eradication rates were 86% (102 of 119), 89% (97 of 109), 91% (106 of 116) and 90% (104 of 115) for Groups 1-4, respectively. The eradication rate was 95% (360 of 379) for clarithromycin-susceptible strains, and 50% (30 of 60) for clarithromycin-resistant strains. The eradication rates were 88% (332 of 379) and 96% (77 of 80) in extensive metabolizers and poor metabolizers, respectively.

CONCLUSIONS

Rabeprazole-based therapies achieved 50% eradication of clarithromycin-resistant H. pylori, and even achieved good rates in extensive metabolizers. Accordingly, rabeprazole can be recommended as part of a first-line proton pump inhibitor-based triple therapy for H. pylori.

Effect of conjugated linoleic acid type, treatment period, and dosage on differentiation of 3T3 cells

This study was conducted to determine effect of CLA and linoleic acid (LA) on cell differentiation, cellular glycerol-3-phosphate dehydrogenase (GPDH) activity, and FA accumulation in differentiating 3T3-L1 cells (3 isomers x 3 treatment periods x 4 doses). The cells were cultured in 24-well plates for proliferation until confluence. Then they were treated with media containing 0, 10, 35, or 70 mg/L (0, 35, 125, or 250 mmol/L, respectively) of LA, cis9,trans11- or trans10,cis12-CLA during early (day 0-2), intermediate and late (day 3-8), or overall (day 0-8) differentiation periods. Dexamethasone, methyl-isobutylxanthine, and insulin were supplemented to the media only for the early period to induce the differentiation. On day 8 of postconfluence the cells were harvested for Oil Red O staining, analysis of GPDH activity, and determination of the FA Concentration. Cellular LA or CLA was found to accumulate in a dose-response manner, mainly during the intermediate/late period. Treatment with trans10,cis12-CLA lowered (P < 0.05) GPDH activity and the concentration of FA including palmitic acid (16:0) and palmitoleic acid (16:1), especially during the intermediate/late and overall periods, or whenever a high dose of 70 mg/L was applied. This also resulted in a higher (P < 0.05) ratio of saturated FA to monounsaturated FA. Treatment with LA or cis9,trans11-CLA lowered cellular FA only when they applied during the early period at a dose of 70 mg/L. The results demonstrated that the inhibitory effects of CLA on differentiation, GPDH activity, and FA accumulation of 3T3-L1 cells are dependent on the isomer type, treatment period, and dose.

Germ-line transformation and RNAi of the ladybird beetle, Harmonia axyridis

To elucidate the molecular mechanisms underlying the tremendous diversity of insect wing colour patterns, it is imperative to identify and functionally characterize the genes involved in this developmental process. Here we report the first successful germ-line transformation using the transposable element vector piggyBac in the ladybird beetle Harmonia axyridis, which demonstrates typical genetic polymorphism in its wing colour patterns. The transformation efficiency by piggyBac was 3.7% per fertile G(0). We investigated the effectiveness of RNAi in Harmonia by injecting EGFP (enhanced green fluorescent protein) dsRNA into early transgenic EGFP-expressing embryos and observed substantial reduction of EGFP fluorescence in 87.2% of hatched larvae. Application of these new genetic tools to non-model insects such as Harmonia will facilitate the broad understanding of developmental mechanisms and evolutionary processes that are inaccessible using established model systems.

Effects of dietary protein and growth hormone-releasing peptide (GHRP-2) on plasma IGF-1 and IGFBPs in Holstein steers

This study was conduct to determine the influence of dietary protein on the response of plasma insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding proteins (IGFBPs) to exogenous growth hormone releasing peptide-2 (GHRP-2 or KP 102) in Holstein steers. Eight 16-month-old Holstein steers were grouped by liveweight to two feeding treatments; high protein (HP; CP 1.38 kg/day and TDN 4.5 kg/day DM intake, n=4) or low protein (LP; CP 0.66 kg/day and TDN 4.42 kg/day DM intake, n=4). The experiment was a single reverse design whereby each group was injected twice daily with GHRP-2 (12.5 microg/kg body weight (BW)/day) or saline solution into the jugular vein for a 6-day period. Plasma IGF-1 in the HP group were higher than in the LP group (P<0.05), but plasma 34 kDa IGFBP-2 was lower in the HP than the LP group (P<0.05). The amplitude of the maximum growth hormone (GH) peaks responding to GHRP-2 injection were higher at day 1 than at day 6 of saline or GHRP-2 treatment in both LP and HP steers (P<0.05). The area under the GH response curve for 180 min after the GHRP-2 injection was not significantly different between the LP and the HP groups at days 1 and 6. A response in plasma IGF-1 concentration to GHRP-2 treatment in the HP group was observed at day 1 (198.9+/-18.1 ng/ml), day 2 (195.2+/-21.1 ng/ml) and day 6 (201.3+/-14.8 ng/ml) (P<0.05). No increase in plasma IGF-1 was observed from GHRP-2 administration in the LP group. Although the response of plasma IGF-1 concentration to GHRP-2 administration was increased in the HP group (P<0.05), there was no apparent effect of GHRP-2 treatment on plasma 38-43 kDa IGFBP-3 and 34 kDa IGFBP-2 at days 2 and 6 of treatment. In conclusion, it is proposed that the 34 kDa IGFBP-2 is sensitive to dietary protein level and may play an important role in the regulation of circulating IGF-1 in ruminant. In addition, increased plasma IGF-1 concentration observed in the HP group in response to the GHRP-2 treatment did not appear to affect plasma IGFBPs.

Comparison of nonmetal and metal hydrophilic photosensitizer, ATX-S10 (Na) and ATN-2, binding with human serum proteins using spectrophotometry

Intermolecular interactions of human serum proteins with a hydrophilic nonmetalloporphyrin, 13,17-bis(1-carboxypropionyl)carbomoylethyl-8-ethenyl-2-hydroxy-3-hydroxyiminoethylidene-2,7,12,18-tetramethylporphyrin sodium salt (ATX-S10 (Na)), or a hydrophilic gallium-metalloporphyrin, diethylenetriamine pentaacetic acid ester of 2-[1-(2-hydroxy-ethoxy)ethyl]-4-vinyl-deuteroporphyrin (IX) Ga complex (ATN-2), were investigated using spectrophotometry. ATX-S10 (Na) caused a bathochromic shift with albumin, high-density lipoprotein and low-density lipoprotein, but little or no shift was observed with hemopexin, transferrin and immunoglobulin G. In contrast, ATN-2 displayed a bathochromic shift only with hemopexin. These results suggest that the association energy of ATX-S10 (Na) with albumin might be slightly greater than that with lipoproteins and that of ATN-2 with hemopexin might be greater than that with other serum proteins.

Improvement in gastric histology following Helicobacter pylori eradication therapy in Japanese peptic ulcer patients

We aimed to determine if successful or failed eradication of Helicobacter pylori with triple therapy causes any difference in gastric mucosal histology. Japanese H. pylori-positive patients with a healed peptic ulcer received high (n = 112) or low (n = 113) doses of triple therapy (omeprazole, amoxicillin and clarithromycin) for 1 week. Biopsies from the greater curvature of the central antrum and upper corpus were taken 6 weeks and 30 weeks after treatment completion, and gastric mucosal histology compared between successful (n = 171) and failed (n = 34) eradication groups. Morphological variables of gastritis were graded according to the updated Sydney System. Successful eradication therapy was defined as improvement in inflammation, neutrophil activity and atrophy; failed eradication therapy as improvement in inflammation and neutrophil activity only. Gastric mucosal atrophy gradually improved (in addition to improvements in inflammation and neutrophil activity) with successful eradication of H. pylori infection.

Gastric restitution is inhibited by dexamethasone, which is reversed by hepatocyte growth factor and rebamipide

BACKGROUND

Glucocorticoids have been shown to induce peptic ulcers, especially when co-administered with NSAIDs. Hepatocyte growth factor (HGF) plays a role in gastric ulcer repair, facilitating the restitution of gastric mucosal epithelial cells. HGF expression is induced by PGs in gastric fibroblasts. We hypothesized that dexamethasone (DEX) may inhibit PG production and HGF expression, thus inhibiting HGF-induced gastric epithelial restitution.

AIM

To investigate the effect of DEX on gastric restitution, using cultured gastric cells, the role of HGF in the restitution inhibited by DEX, and the effect of rebamipide on DEX- inhibited restitution.

METHODS

Human gastric fibroblasts were prepared from human stomach obtained at surgery; PGE2 and HGF is determined by ELISA; Restitution was assessed by the round wound restitution model, using coculture of gastric fibroblasts and epithelial cells; COX-2 and HGF mRNA were quantified by TaqMan RT-PCR system.

RESULTS

1. DEX inhibited HGF mRNA and COX-2 mRNA. Accordingly, it inhibited PGE2 and HGF release. 2. DEX inhibited the restitution of gastric cells. 3. The inhibition of restitution was reversed by HGF and rebamipide to the same extent. 4. Rebamipide induced PGE2 and HGF.

CONCLUSION

DEX inhibits restitution via HGF depletion, and rebamipide reverses the inhibited restitution by HGF induction.

Effects of rebamipide, a gastro-protective drug on the Helicobacter pylori status and inflammation in the gastric mucosa of patients with gastric ulcer: a randomized double-blind placebo-controlled multicentre trial

AIMS

To investigate the effects of rebamipide on the Helicobacter pylori eradication rate with amoxicillin and omeprazole. The trial also examined its histological effects on gastro-mucosal inflammation after eradication.

METHODS

Two hundred and six H. pylori-positive patients with active gastric ulcer underwent 8-week based therapy (OA) consisting of 2-week amoxicillin with omeprazole and subsequent 6-week omeprazole. They randomly received either rebamipide (OA-R) or placebo (OA-P) for 16 weeks: combined with the OA based therapy, and subsequently for another 8 weeks. Besides eradication rate, inflammatory findings of gastric mucosa after eradication were evaluated histologically.

RESULTS

Per Protocol Set analysis showed no significant difference in eradication rate between OA-R (64.6%; 95% confidence interval, 54.3-75.0%) and OA-P (67.9%; 95% CI, 57.6-78.3%). Histological findings in the gastric mucosa of the ulcer region, however, indicated a significant improvement (P = 0.017) in inflammation scores in OA-R (1.84 +/- 0.41) compared with that in OA-P (2.02 +/- 0.39) after 16-weeks of treatment. This suppressive effect on inflammation was observed even in the OA-R patients unsuccessfully eradicated.

CONCLUSION

Rebamipide demonstrated a suppressive effect on the persistent and possibly chronic inflammation in the gastric mucosa of the ulcer region after eradication, but the drug did not improve the eradication rate.