Methods to improve efficacy of orally administered bioactive peptides using bovine colostrum as an exemplar.

BACKGROUND: Oral administration of bioactive peptides has potential clinical advantages, but its applicability is limited due to gastric and pancreatic enzyme proteolysis. OBJECTIVE: To examine whether the co-packaging of bovine colostrum (BC), a rich source of IgG, immune and growth factors, with the food additives trehalose (carbohydrate), stearine (fat), casein (protein present in BC) or soy flour (plant based with high protease inhibitory activity) enhances the stability of BC against digestion. DESIGN: Samples alone and in combination (BC+ 10% wt/wt trehalose, stearine, casein or soy) were exposed to HCl/pepsin, followed by trypsin and chymotrypsin ("CT"). Assessment of proliferation used gastric AGS cells (Alamar blue), IgG function measured bovine IgG anti-E.coli binding and ELISAs quantified growth factor constituents. In vivo bioassay assessed ability of BC alone or with soy to reduce injury caused by dextran sodium sulphate (DSS, 4% in drinking water, 7 days, test products started 2 days prior to DSS). RESULTS: Proliferative activity of BC reduced 61% following HCl/pepsin and CT exposure. This was truncated 50% if soy was co-present, and also protected against loss of total IgG, IgG E.coli binding, TGFß, lactoferrin and EGF (all P<0.01 vs BC alone). Co-packaging with trehalose was ineffective in preventing digestion whereas casein or stearine provided some intermediate protective effects. Rats given BC alone showed beneficial effects on weight gain, disease activity index, tissue histology and colonic MPO. Soy alone was ineffective. BC+ soy combination showed the greatest benefit with a dose of 7 mg/kg (6.4 BC + 0.6 soy flour) having the same degree of benefit as using 20 mg/kg BC alone. CONCLUSION: Soy, and to a lesser extent casein, enhanced the biostability of BC against digestive enzymes. Co-packaging of BC with other food products such as soy flour could result in a decreased dose being required, improving cost-effectiveness and patient compliance.

Poor clinical outcomes of intratumoral dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin-positive macrophages associated with immune evasion in gastric cancer.

AIM: Tumour-associated macrophages (TAMs) are prominent immune cells infiltrating in solid tumours with phenotypic and functional heterogeneity. However, the clinical significance of heterogeneous subtypes of TAMs in gastric cancer still remains obscure. Here, we aimed to explore the clinical significance of TAMs expressing dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) and its relevance with immune contexture in gastric cancer. METHODS: We selected 453 formalin-fixed and paraffin-embedded samples and 51 fresh tissue specimens of patients with gastric cancer from Zhongshan Hospital. The association of DC-SIGN+ macrophages with clinicopathological parameters, overall survival (OS) and responsiveness to fluorouracil-based adjuvant chemotherapy (ACT) was inspected. Immunohistochemistry (IHC) and flow cytometry (FCM) were applied to characterize immune cells in gastric cancer. RESULTS: We demonstrated that high intratumoral DC-SIGN+ macrophages infiltration predicted poor OS and inferior therapeutic responsiveness to fluorouracil-based ACT in patients with gastric cancer. Furthermore, higher infiltration of DC-SIGN+ macrophages indicated an increased number of Foxp3+ regulatory T cells (Tregs), CD8+ T cells and a higher ratio of Foxp3+/CD8+ within the tumour microenvironment (TME). In addition, CD8+ T cells in DC-SIGN+ macrophages high subgroup were functionally impaired, showing decreased interferon-γ (IFN-γ), granzyme B (GZMB) and perforin production yet elevated programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) expression. CONCLUSIONS: DC-SIGN+ macrophages were associated with immunoinvasive TME and indicated poor prognosis and inferior therapeutic responsiveness to fluorouracil-based ACT. DC-SIGN+ macrophages might be an independent prognosticator and a potential immunotherapeutic target for gastric cancer.

Lycopene treatment inhibits activation of Jak1/Stat3 and Wnt/ß-catenin signaling and attenuates hyperproliferation in gastric epithelial cells.

Helicobacter pylori (H pylori) colonizes the human stomach and increases the risk of gastric diseases including gastric cancer. H pylori increases reactive oxygen species (ROS), which activate Janus-activator kinase 1 (Jak1)/signal transducers and activators of transcription 3 (Stat3) in gastric epithelial cells. ROS mediate hyperproliferation, a hallmark of carcinogenesis, by activating Wnt/ß-catenin signaling in various cells. Lycopene is a potent antioxidant exhibiting anticancer effects. We hypothesized that lycopene may inhibit H pylori-induced hyperproliferation by suppressing ROS-mediated activation of Jak1/Stat3 and Wnt/ß-catenin signaling, and ß-catenin target gene expression in gastric epithelial cells. We determined cell viability, ROS levels, and the protein levels of phospho- and total Jak1/Stat3, Wnt/ß-catenin signaling molecules, Wnt-1, lipoprotein-related protein 5, and ß-catenin target oncogenes (c-Myc and cyclin E) in H pylori-infected gastric epithelial AGS cells. The Jak1/Stat3 inhibitor AG490 served as the control treatment. The significance of the differences among groups was calculated using the 1-way analysis of variance followed by Newman-Keuls post hoc tests. The results show that lycopene reduced ROS levels and inhibited Jak1/Stat3 activation, alteration of Wnt/ß-catenin multiprotein complex molecules, expression of c-Myc and cyclin E, and cell proliferation in H pylori-infected AGS cells. AG490 similarly inhibited H pylori-induced cell proliferation, alteration of Wnt/ß-catenin multiprotein complex molecules, and oncogene expression. H pylori increased the levels of Wnt-1 and its receptor lipoprotein-related protein 5; this increase was inhibited by either lycopene or AG490 in AGS cells. In conclusion, lycopene inhibits ROS-mediated activation of Jak1/Stat3 and Wnt/ß-catenin signaling and, thus, oncogene expression in relation to hyperproliferation in H pylori-infected gastric epithelial cells. Lycopene might be a potential and promising nutrient for preventing H pylori-associated gastric diseases including gastric cancer.

Pectin, beta-cyclodextrin, chitosan and albumin based gastroprotective systems for piroxicam maleate: Synthesis, characterization and biological evaluation.

In order to optimize drug action, new drug formulations have been developed based upon the prodrug approach. This study was inspired by the increasing interest in the field of macromolecular prodrugs and Piroxicam maleate was used as a model drug. A total of five prodrugs were synthesized using beta cyclodextrin, chitosan, pectin, egg albumin, bovine serum albumin. The synthesized conjugates were characterized on the basis of UV, IR and NMR techniques. In-vitro hydrolysis studies were carried out at pH 1.2, pH 7.4, pH 9.0 and in 80% human plasma followed by in-vivo evaluation of analgesic, anti-inflammatory and anti-ulcerogenic potential. The extent of hydrolysis was found to be proportional to increase in pH. Beta cyclodextrin conjugate was found to possess significant analgesic activity whereas chitosan conjugate was found to be the best anti-inflammatory. Pectin conjugate provided maximum protection against ulcers.

Yangzheng Sanjie decoction regulates proliferation and apoptosis of gastric cancer cells by enhancing let-7a expression.

AIM: To explore the let-7a-mediated anti-cancer effect of Yangzheng Sanjie decoction (YZSJD) in gastric cancer (GC) cells. METHODS: YZSJD-containing serum (YCS) was prepared using traditional Chinese medicine serum pharmacology methods. After YCS treatment, cell proliferation and apoptosis were assessed by cell counting kit-8 assay and flow cytometry, respectively, and miRNA expression profiles were determined using qPCR arrays. Let-7a expression was examined by in situ hybridization in GC tissues and by qPCR in GC cells. c-Myc protein expression was detected by immunohistochemistry in GC tissues, and by Western blot in cell lines. RESULTS: YZSJD significantly inhibited proliferation and induced apoptosis in AGS and HS-746T GC cells. After treatment with YCS, the miRNA expression profiles were altered and the reduced let-7a levels in both cell lines were up-regulated, accompanied by a decrease in c-Myc expression. Moreover, decreased let-7a expression and increased c-Myc expression were observed during the progression of gastric mucosa cancerization. CONCLUSION: YZSJD inhibits proliferation and induces apoptosis of GC cells by restoring the aberrant expression of let-7a and c-Myc.

Cytokine changes in gastric and colonic epithelial cell in response to Planta ovata extract.

Background Psyllium (Planta ovata, Ispaghul) seed and husk are used for treatment of altered bowel habit, i. e. constipation and diarrhea. We studied the effect of Ispaghul extract on secretion of interleukin-1 beta (IL-1ß) by AGS (ATCC CRL 1739) and SW480 (ATCC CCL-227) epithelial cell lines and determined whether Ispaghul extract has an effect on IL-1ß secretion by Helicobacter pylori (H. pylori)-stimulated AGS cell and Escherichia coli K-12 (E. coli K-12)-stimulated SW480 cells in vitro. Methods The AGS cells and SW480 cells were pretreated with Ispaghul extract in concentrations, i. e. 3.5 and 7 µg/mL prior to infection with H. pylori and E. coli K-12. Results DNA fragmentation in AGS and SW480 cells treated with Ispaghul extract was not significant (2.3±0.8 %) compared with untreated cells (2.2±0.6 %). Ispaghul extract decreased the H. pylori-stimulated secretion of IL-1ß by AGS cell (p<0.0001). This effect did not increase as the concentration of extract was increased. Ispaghul extract also decreased E. coli K-12-stimulated IL-1ß secretion by SW480 cell (p<0.0001). This effect increased as the concentration of extracts was increased. Conclusions Ispaghul extract had an effect on stimulated secretion of IL-1ß by the AGS and SW480 cell. It decreased pro-inflammatory reaction from both cell lines stimulated by bacteria.

Gastroprotective effects of montelukast and Nigella sativa oil against corticosteroid-induced gastric damage: they are much more than antiasthmatic drugs.

Corticosteroids are used to treat a variety of diseases like bronchial asthma. However, long-term corticosteroids have a gastric ulcerogenic potential. Montelukast (MTK) and Nigella sativa oil (NSO) are used in treatment of bronchial asthma. Previous studies showed that MTK and NSO had gastroprotective effects in other models of gastric ulcer. The present study assesses synergistic gastroprotective effects of both drugs in dexamethasone (DXM)-induced gastric damage. Fifty male rats were divided into 5 groups: normal control (I), DXM group (II), MTK + DXM group (III), NSO + DXM group (IV), MTK + NSO + DXM group (V). After 7 days, stomachs were removed for biochemical analysis and histological examinations. Significant increases in malondialdehyde (MDA) level, superoxide dismutase (SOD) activity, myeloperoxidase (MPO) activity, and proliferating cell nuclear antigen (PCNA) positive cells, with significant decreases in mucus secretion were detected in DXM-treated group compared with group I. Meanwhile, significant decreases of MDA level, MPO activity, and PCNA positive cells and significant increases in mucus secretion were detected in treated groups compared with group II. SOD activity significantly decreased in group V compared with group II. We could conclude that administration of either MTK or NSO or both with DXM counteracts DXM-induced gastric lesions.

Effect of Delonix regia (Boj. Ex Hook.) Raf. stem bark extract against experimentally induced ulcers in rats.

Delonix regia, commonly called Flame Tree or Flamboyant (locally, Gul Mohor) is a common tree traditionally used to treat various diseases like gastric problems, body pain, rheumatic pains of joints and wound healing. Here, we carried out biological profiling of Delonix regia as antiulcer agent. Antiulcer activity of the ethanol extract from stem bark was evaluated on pylorus ligation and indomethacin induced ulcer in Wistar albino rats. Ethanol extract from stem bark of D.regia was administered at the doses 100, 200 and 400 mg/kg/day, p.o. for 7 days. Ulcer index, gastric pH, volume, free acidity, total acidity, total carbohydrate (TC), protein (P), mucin content (TC/P) and gastric mucus were evaluated in pylorus ligation model, while ulcer index, malondialdehyde, GSH, PGE2, and gastric mucus were estimated in the indomethacin induced ulcer model. Ex vivo assay for the activity of H+/K+-ATPase was also done. The results showed significant inhibition on H+/K+-ATPase in a dose dependent manner and comparableto their respective positive control group of rats demonstrating that ethanol extract of stem bark of Delonix regia possesses significant antiulcer properties.

Astragaloside IV inhibits pathological functions of gastric cancer-associated fibroblasts.

AIM: To investigate the inhibitory effect of astragaloside IV on the pathological functions of cancer-associated fibroblasts, and to explore the underlying mechanism. METHODS: Paired gastric normal fibroblast (GNF) and gastric cancer-associated fibroblast (GCAF) cultures were established from resected tissues. GCAFs were treated with vehicle control or different concentrations of astragaloside IV. Conditioned media were prepared from GNFs, GCAFs, control-treated GCAFs, and astragaloside IV-treated GCAFs, and used to culture BGC-823 human gastric cancer cells. Proliferation, migration and invasion capacities of BGC-823 cells were determined by MTT, wound healing, and Transwell invasion assays, respectively. The action mechanism of astragaloside IV was investigated by detecting the expression of microRNAs and the expression and secretion of the oncogenic factor, macrophage colony-stimulating factor (M-CSF), and the tumor suppressive factor, tissue inhibitor of metalloproteinase 2 (TIMP2), in different groups of GCAFs. The expression of the oncogenic pluripotency factors SOX2 and NANOG in BGC-823 cells cultured with different conditioned media was also examined. RESULTS: GCAFs displayed higher capacities to induce BGC-823 cell proliferation, migration, and invasion than GNFs (P < 0.01). Astragaloside IV treatment strongly inhibited the proliferation-, migration- and invasion-promoting capacities of GCAFs (P < 0.05 for 10 µmol/L, P < 0.01 for 20 µmol/L and 40 µmol/L). Compared with GNFs, GCAFs expressed a lower level of microRNA-214 (P < 0.01) and a higher level of microRNA-301a (P < 0.01). Astragaloside IV treatment significantly up-regulated microRNA-214 expression (P < 0.01) and down-regulated microRNA-301a expression (P < 0.01) in GCAFs. Reestablishing the microRNA expression balance subsequently suppressed M-CSF production (P < 0.01) and secretion (P < 0.05), and elevated TIMP2 production (P < 0.01) and secretion (P < 0.05). Consequently, the ability of GCAFs to increase SOX2 and NANOG expression in BGC-823 cells was abolished by astragaloside IV. CONCLUSION: Astragaloside IV can inhibit the pathological functions of GCAFs by correcting their dysregulation of microRNA expression, and it is promisingly a potent therapeutic agent regulating tumor microenvironment.

Hepato- and gastro- protective activity of purified oat 1-3, 1-4-ß-d-glucans of different molecular weight.

Protective and antioxidant properties of highly purified oat ß-glucans of high and low molecular weight in liver and stomach were evaluated. The novelty in approach was to determine whether dietary ß-glucans affect the parameters of oxidative stress directly in the stomach and indirectly in the liver, especially in inflammation states. Physicochemical properties e.g. viscoelastic was found as strictly dependent from molecular weight of oat ß-glucans hence its metabolic activity could also show dependence. Three groups of rats were fed control diet and diet supplemented with low and high molecular weights oat ß-glucans. Animals were divided into controls and individuals with experimentally induced intestinal inflammation. Most active in increasing of total antioxidant status was low molecular weight ß-glucan. High molecular weight ß-glucan supplementation inhibits lipid oxidation the most in LPS treated animals. The results obtained from experiment encourage for dietary intervention with oat ß-glucans for stomach and liver protection during existing enteritis.

Impact of an Energy Drink on the Structure of Stomach and Pancreas of Albino Rat: Can Omega-3 Provide a Protection?

BACKGROUND AND OBJECTIVES: A controversy developed between the benefits of energy drinks (EDs) versus the possible health threats since its revolution. Lack of information was a call to assess the effect of chronic consumption of Power Horse (PH) as one of the EDs, on the structure of pancreas and fundic mucosa of stomach in rats, and possible protective role of Omega-3. MATERIALS AND METHODS: Thirty two adult male albino rats were divided equally into 4 groups; control received group which only received a standard diet, Omega-3 group, PH group which given PH and PH plus Omega-3 group received both PH plus Omega-3 for 4 weeks. Biochemical assessment of blood glucose, serum insulin, gastrin, tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthetase (iNOS) was performed. The antioxidant activity and histopathological examination of both pancreatic tissue and fundic mucosa of stomach were assessed. RESULTS: Administration of PH significantly increased serum insulin and glucose levels while it significantly reduced serum gastrin level compared to control. PH also caused oxidants/antioxidants imbalance in both pancreas and fundic mucosa. The latter revealed degenerative changes and increased apoptosis which was evident by increased caspase-3 immunoexpression. Pancreas exhibited signs of ß-cells overstimulation. Fundic mucosa showed reduced number of parietal cells, gastrin hormone expression compared to control group. Omega-3 administration could alleviate, to some extent, these changes. It significantly decreased TNF-α, iNOS and reduced glutathione (GSH) as well as significantly increasing superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities compared to the group which received PH alone. CONCLUSION: Power Horse intake significantly injures islet cells, pancreatic acini as well as the glandular cells of the fundic mucosa. Omega-3 decreases these detrimental effects mostly through its antioxidant and anti-inflammatory action.

Antimutagenicity and induction of antioxidant defense by flavonoid rich extract of Myrcia bella Cambess. in normal and tumor gastric cells.

ETHNOPHARMACOLOGICAL RELEVANCE: The Brazilian "Cerrado" is an important source of natural products, such as Myrcia bella Cambess (MB, also known as "mercurinho"). MB leaves are popularly used for the treatment of diabetes and gastrointestinal disorders; however, only its hypoglycemic activity has been experimentally described. AIM OF THE STUDY: Because MB is used to treat gastrointestinal disorders, the present study characterized biological activities of hydroalcoholic MB extract in human normal and tumor gastric cells. MATERIALS AND METHODS: Cytotoxic, antiproliferative, genotoxic and protective effects were evaluated, as well as the effects of the MB extract on gene expression. RESULTS: The MB extract induced cytotoxicity in tumor cells at lower concentrations compared with normal cells as assessed by the MTT assay. Moreover, the MB extract induced necrosis based on acridine orange/ethidium bromide staining. An antiproliferative effect was evidenced through an arrest in the G2/M phase detected by flow cytometry and a decrease in the nuclear division index using the cytokinesis-block micronucleus cytome assay. Cells treated with MB extract combined with doxorubicin (DXR) showed increased NUBDs, which may be related to the gene amplification of CCND1. Antimutagenic effects were also observed and may be associated with the antioxidant activities detected using the CM-H2DCFDA probe. CONCLUSIONS: Our findings showed the following: (a) high concentrations of MB induced cytotoxicity and cell death by necrosis; (b) its antiproliferative effect was associated with G2/M arrest; and (c) its antioxidant activity could be responsible for the observed antimutagenic effects and for protective effects against gastrointestinal disorders previously described to MB. Although these effects are not specific to normal or tumor cells, they provide a panel of biological activities for further exploration.

Effect of vertical sleeve gastrectomy on food selection and satiation in rats.

Vertical sleeve gastrectomy (VSG) is a restrictive procedure that reduces food intake to produce weight loss. Here we assess volume and nutrient effects on the ingestive behavior of VSG and sham surgery animals. Rats given access to Ensure or pelleted chow were used to determine if liquid foods would adversely affect weight loss after surgery. Volume effects were studied by altering the caloric density of Ensure, and dietary preferences for fat and carbohydrate (sucrose) were assessed using a two-bottle test. c-Fos was used to measure neuronal activation in the nucleus of the solitary tract and area postrema in response to intragastric infusions of water, sucrose, or Intralipid. The degree of colocalization with catecholaminergic neurons was also assessed. VSG rats did not show the expected preference for a liquid diet over chow and lacked dietary preferences for fat seen in shams. Preferences for carbohydrate/sucrose solutions were unaffected by surgery. Meal size was reduced by VSG; however, VSG rats were able to alter their volume of intake to compensate for changes in caloric density, and intragastric infusions of water produced similar levels of neuronal activation among VSG, sham, and pair-fed rats. In comparison, nutrient-induced c-Fos activation was substantially increased by VSG. Colocalization between c-Fos and catecholaminergic-expressing neurons was similar among rats treated with water, sucrose, or Intralipid. VSG alters nutrient sensing in a manner that lowers the threshold for satiety and reduces fat preference to induce and maintain weight loss.

Gastric antisecretory and cytoprotective effects of leaf extracts of Amaranthus tricolor Linn. in rats.

OBJECTIVE: The present study was aimed to evaluate the antiulcer activity of leaf extracts of Amaranthus tricolor Linn. (Amaranthaceae) in rats. METHODS: The effects of A. tricolor leaves on gastric secretion and the effect of gastric cytoprotection were evaluated using five different models of gastric ulcers: acetic acid-induced, pylorus ligation-induced, ethanol-induced, indomethacin-induced and ischemia-reperfusion-induced gastric ulcers. The different extracts, namely, ethanolic extract (EAT), petroleum ether extract (PEAT), chloroform extract (CAT) and ethyl acetate extract (EAAT) of A. tricolor leaves were administered at a dose of 200 mg/kg per oral (p.o.). RESULTS: The acute oral toxicity study revealed that all the extracts were safe up to 2 000 mg/kg, p.o; hence one-tenth of this dose was selected for evaluation of antiulcer activity. The EAT and EAAT (200 mg/kg, p.o.) showed gastric ulcer-healing effect in acetic acid-induced chronic gastric ulcers. The EAT and EAAT inhibited gastric secretion in pylorus-ligated rats and showed gastric cytoprotective effect in ethanol-induced and indomethacin-induced gastric ulcers, while PEAT and CAT showed no significant antiulcer effect. CONCLUSION: The leaf extracts of A. tricolor are found to possess very good antiulcer property in the experimental animal models of gastric ulcers which is consistent with the literature report in folk medicine.

In vivo antimutagenic properties of transgenic and conventional soybeans.

The goal of the this study was to evaluate the mutagenic/antimutagenic effects of conventional (BRS133) and transgenic (BRS 245 RR) soybeans (CS and TS, respectively) in vivo using the bone marrow micronucleus (MN) test, histopathological analysis, chromosome aberration test (CAT), and mitotic index (MI) determination. Six-week-old male Swiss mice were fed with pelleted commercial diet mixed with CS or TS at 10% or 20%. Two experimental designs (MN and CAT) were conducted simultaneously with 10 groups each during a 15-day period. Animals were treated with pelleted commercial diet, CS (10% or 20%), or TS (10% or 20%), and on day 14 they also received cyclophosphamide (CP) (50 mg/kg i.p.). The 10% and 20% CS and TS diets did not significantly decrease the frequencies of micronucleated polychromatic erythrocytes in bone marrow induced by CP. However, the CAT indicated that the 10% and 20% CS diets significantly (P < .05) protected nucleated bone marrow cells against chemical-induced mutagenesis and also produced a significant (P < .05) decrease in the total percentage of spontaneous aberrations. Among the treatments with TS, only the 10% TS diet reduced the percentage of total aberrations induced by CP. The results also indicated that the treatment with 20% TS alone significantly (P < .05) decreased the MI, indicating cytotoxic effects related to the treatment. Taken together, our results suggest that, under the tested conditions, TS and CS have antimutagenic properties and are not toxic.

Selective expression of TLQP-21 and other VGF peptides in gastric neuroendocrine cells and modulation by feeding.

Although vgf gene knockout mice are hypermetabolic, administration of the VGF peptide TLQP-21 itself increased energy consumption. Agonist-antagonist roles are thus suggested for different VGF peptides, and the definition of their tissue heterogeneity is mandatory. We studied the rat stomach using antisera to C- or N-terminal sequences of known or predicted VGF peptides in immunohistochemistry and ELISA. TLQP (rat VGF(556-565)) peptide/s were most abundant (162±11 pmol/g, mean±s.e.m.) and were brightly immunostained in enterochromaffin-like (ECL) cells and somatostatin cells. A peptide co-eluting with TLQP-21 was revealed in HPLC of gastric and hypothalamic extracts, while the extended TLQP-62 form was restricted to the hypothalamus. Novel PGH (rat VGF(422-430)) peptide/s were revealed in ghrelin cells, mostly corresponding to low MW forms (0.8-1.5  kDa), while VGF C-terminus peptides were confined to neurons. VGF mRNA was present in the above gastric endocrine cell types, and was prominent in chief cells, in parallel with low-intensity staining for further cleaved products from the C-terminal region of VGF (HVLL peptides: VGF(605-614)). In swine stomach, a comparable profile of VGF peptides was revealed by immunohistochemistry. When fed and fasted rats were studied, a clear-cut, selective decrease on fasting was observed for TLQP peptides only (162±11 vs 74±5.3  pmol/g, fed versus fasted rats, mean±s.e.m., P<0.00001). In conclusion, specific VGF peptides appear to be widely represented in different gastric endocrine and other mucosal cell populations. The selective modulation of TLQP peptides suggests their involvement in peripheral neuro-endocrine mechanisms related to feeding responses and/or ECL cell regulation.

In vitro inhibition of Helicobacter pylori growth and of adherence of cagA-positive strains to gastric epithelial cells by Lactobacillus paraplantarum KNUC25 isolated from kimchi.

Lactobacillus paraplantarum KNUC25 strain was isolated from overfermented kimchi, a Korean traditional food. The strain had a broad antimicrobial activity spectrum, from gram-positive to gram-negative bacteria. The aim of this study was to evaluate the activity of L. paraplantarum KNUC25 against Helicobacter pylori strains. Judged by a disc agar diffusion method, the anti-H. pylori activity existed in the cell-free supernatants (CFSs) of KNUC25. The mean diameters of growth inhibition by 10, 30, and 60 microL of a 15-fold concentrated CFS per disc were 11.2, 17.7, and 23.7 mm, respectively. The neutralized CFS lost its anti-H. pylori activity, suggesting that acidic pH in CFS may be responsible for the anti-H. pylori activity. Adherence was determined by urease activity of H. pylori adhered to gastric epithelial cell line AGS cells after co-incubation of AGS cells with CFS and H. pylori strain ATCC43504 (s1m1vacA/cagA(+)), ATCC51932 (s2m2vacA/cagA(-)), or SS1 (s2m2vacA/cagA(+)) in vitro followed by three washes by means of centrifugation with saline. Adherence of ATCC43504 or SS1 to AGS cells was reduced by about 70% after a 30-minute incubation with 30 microL of a 15-fold concentrated KNUC25 CFS, whereas that of ATCC51932 to AGS cells was not. The results show KNUC25 CFS is effective in inhibiting the growth of H. pylori, which is related to pH and the adherence of cagA-positive H. pylori to gastric cells.

Effects of electrical stimulation on isolated rodent gastric smooth muscle cells evaluated via a joint computational simulation and experimental approach.

Gastric electrical stimulation (GES) involves the delivery of electrical impulses to the stomach for therapeutic purposes. New GES protocols are needed that are optimized for improved motility outcomes and energy efficiency. In this study, a biophysically based smooth muscle cell (SMC) model was modified on the basis of experimental data and employed in conjunction with experimental studies to define the effects of a large range of GES protocols on individual SMCs. For the validation studies, rat gastric SMCs were isolated and subjected to patch-clamp analysis during stimulation. Experimental results were in satisfactory agreement with simulation results. The results define the effects of a wide range of GES parameters (pulse width, amplitude, and pulse-train frequency) on isolated SMCs. The minimum pulse width required to invoke a supramechanical threshold response from SMCs (defined at -30 mV) was 65 ms (at 250-pA amplitude). The minimum amplitude required to invoke this threshold was 75 pA (at 1,000-ms pulse width). The amplitude of the invoked response beyond this threshold was proportional to the stimulation amplitude. A high-frequency train of stimuli (40 Hz; 10 ms, 150 pA) could invoke and maintain the SMC plateau phase while requiring 60% less power and accruing approximately 30% less intracellular Ca(2+) concentration during the plateau phase than a comparable single-pulse protocol could in a demonstrated example. Validated computational simulations are an effective strategy for efficiently identifying effective minimum-energy GES protocols, and pulse-train protocols may also help to reduce the power consumption of future GES devices.

Dietary supplementation with zinc oxide stimulates ghrelin secretion from the stomach of young pigs.

Dietary supplementation with zinc is known to enhance food intake and growth in young children. However, the underlying mechanisms remain largely unknown. Ghrelin, a peptide derived mainly from stomach, plays an important role in food-intake regulation. The present study was conducted with the piglet model to test the hypothesis that zinc may increase gastric ghrelin secretion. In Experiment 1 (Exp. 1) , thirty-six 28-day-old weaned pigs were assigned to two groups (18 pigs/group), receiving four-week supplementation of 0 or 2000 mg/kg Zn (as ZnO) to the basal diet containing 100 mg/kg Zn. In Experiment (Exp. 2), sixteen 28-day-old piglets were assigned to the same treatments (n=8/group) as in Exp. 1, except that they were pair-fed an equal amount of diet. At the end of the experiments, blood, stomach and duodenum samples were obtained for biochemical analysis, including assays of ghrelin protein and insulin-like growth factor-I (IGF-I) in plasma, as well as quantification of ghrelin and IGF-I mRNA levels in the duodenum and gastric mucosa. Further, gastric mucosal cells from unsupplemented piglets were cultured with 0-0.5 mM ZnO for 2-24 h for assays of ghrelin production and gene expression. Dietary Zn supplementation increased plasma concentrations of ghrelin, IGF-I and cholecystokinin; IGF-I gene expression in the duodenum as well as food intake and piglet growth (Exp. 1). The effects of ZnO on plasma levels of ghrelin, intestinal IGF-I expression and piglet growth were independent of food intake. Addition of ZnO to culture medium enhanced ghrelin production from gastric mucosal cells without affecting ghrelin mRNA levels. Collectively, our results indicate that ZnO stimulates ghrelin secretion from the stomach at the post-transcriptional level. This novel finding aids in elucidating the cellular and molecular mechanism for a role of zinc in promoting food intake and growth of young children.

Gastroprotective effect and cytotoxicity of semisynthetic jatropholone derivatives.

The gastroprotective effect of the diterpenes jatropholone A, jatropholone B and 16 semisynthetic derivatives was assessed in the HCl/ethanol-induced gastric lesion model in mice and the cytotoxicity was determined towards fibroblasts and AGS cells. In a dose-response study, jatropholone B reduced gastric lesions by 65% at 6 mg/kg and jatropholone A by 54% at 100 mg/kg. The jatropholone B derivatives 9 - 14 and the compounds 15 - 18 were compared at a single oral dose of 25 mg/kg while the jatropholone A derivatives 2 - 7 were assessed at 100 mg/kg. A decrease in gastroprotective activity was observed for the ether as well as for the ester derivatives of jatropholone B. The methyl and propyl ethers of jatropholone A were more gastroprotective than the natural product. The placement of an additional methyl group at C-2 in the jatropholone B derivatives led to a loss of selectivity, the methyl and propyl ethers lack a gastroprotective effect. Jatropholone B was not toxic towards AGS cells and fibroblasts. Jatropholone A was active only against AGS cells. The gastroprotective effect of the epimeric jatropholones was selective showing a higher effect for jatropholone B. These results further support that the stereochemistry of the methyl group at C-2 in the jatropholones plays a relevant role in preventing the gastric lesions in mice. The compounds 3, 5 - 7, 10 and 12 - 18 are described for the first time.