Prolongation of the gastric residence time of caffeine after administration in fed state: Comparison of effervescent granules with an extended release tablet.

The aim of the present study was to investigate the gastroretentive capacity of different formulation principles. This was indirectly determined by the absorption behavior of caffeine from the dosage forms. A slow and continuous appearance of caffeine in the saliva of healthy volunteers was used as a parameter for a prolonged gastric retention time. For this purpose, a four-way study was conducted with twelve healthy volunteers using the following test procedures: (1) Effervescent granules with 240 mL of still water administered in fed state, (2) effervescent granules with 20 mL of still water in fed state, (3) extended release (ER) tablet with 240 mL of still water in fed state, and (4) effervescent granules with 240 mL of still water in fasted state. The initial rise of the caffeine concentrations was more pronounced after the intake of the effervescent granules in the fed state compared to that of the ER tablets. However, tmax tended to be shorter in the fed study arms following administration of the ER tablet compared to the granules. Overall, the application of active pharmaceutical ingredients formulated as effervescent granules seems to be a promising approach to increase their gastric residence time after intake in fed state.

In Vitro Simulation of the Fasted Gastric Conditions and Their Variability to Elucidate Contrasting Properties of the Marketed Dabigatran Etexilate Pellet-Filled Capsules and Loose Pellets.

Variability of the gastrointestinal tract is rarely reflected in in vitro test protocols but often turns out to be crucial for the oral dosage form performance. In this study, we present a generation method of dissolution profiles accounting for the variability of fasted gastric conditions. The workflow featured 20 biopredictive tests within the physiological variability. The experimental array was constructed with the use of the design of experiments, based on three parameters: gastric pH and timings of the intragastric stress event and gastric emptying. Then, the resulting dissolution profiles served as a training data set for the dissolution process modeling with the machine learning algorithms. This allowed us to generate individual dissolution profiles under a customizable gastric pH and motility patterns. For the first time ever, we used the method to successfully elucidate dissolution properties of two dosage forms: pellet-filled capsules and bare pellets of the marketed dabigatran etexilate product Pradaxa. We showed that the dissolution of capsules was triggered by mechanical stresses and thus was characterized by higher variability and a longer dissolution onset than observed for pellets. Hence, we proved the applicability of the method for the in vitro and in silico characterization of immediate-release dosage forms and, potentially, for the improvement of in vitro-in vivo extrapolation.

Bisphenol A and selenium deficiency exposure induces pyroptosis and myogenic differentiation disorder in chicken muscle stomach.

Bisphenol A (BPA), which is commonly found in the environment due to its release from the use of plastics and food overpacks, has become a major stressor for environmental sustainability and livestock and poultry farming health. Selenium (Se) deficiency causes structural damage and inflammatory responses to the digestive system and muscle tissue, and there is a potential for concurrent space-time exposure to nutritional deficiency diseases and environmental toxicants in livestock and poultry. The mechanisms of damage to chicken muscular stomach from BPA or/and Se deficiency treatment are still not known. Here, we established a chicken model of BPA (20 mg/kg) or/and Se deficiency (0.039 mg/kg) exposure, and detected histopathological changes in the muscular stomach tissue, the levels of iNOS/NO pathway, IL-6/JAK/STAT3 pathway, pyroptosis, and myogenic differentiation by H&E staining, immunofluorescence staining, real-time quantitative PCR, and western blot methods. The data revealed that BPA or Se deficiency exposure caused gaps between muscle fibers with inflammatory cell infiltration; up-regulation of the iNOS/NO pathway and IL-6/JAK/STAT3 pathway; up-regulation of NLRP3/Caspase-1-dependent pyroptosis related genes; down-regulation of muscle-forming differentiation (MyoD, MyoG, and MyHC) genes. The combination of BPA and Se deficiency was associated with higher toxic impairment than alone exposure. In conclusion, we discovered that BPA and Se deficiency caused myogastric pyroptosis and myogenic differentiation disorder. These findings provide a theoretical basis for the co-occurrence of animal nutritional deficiency diseases and environmental toxicant exposures in livestock and poultry farming, and may provide important insights into limiting the production of harmful substances.

Effects of corticotropin-releasing hormone on gastric electrical activity and sensorimotor function in healthy volunteers: a double-blinded crossover study.

Biopsychosocial factors are associated with disorders of gut-brain interaction (DGBI) and exacerbate gastrointestinal symptoms. The mechanisms underlying pathophysiological alterations of stress remain unclear. Corticotropin-releasing hormone (CRH) is a central regulator of the hormonal stress response and has diverse impact on different organ systems. The aim of the present study was to investigate the effects of peripheral CRH infusion on meal-related gastrointestinal symptoms, gastric electrical activity, and gastric sensorimotor function in healthy volunteers (HVs). In a randomized, double-blinded, placebo-controlled, crossover study, we evaluated the effects of CRH on gastric motility and sensitivity. HVs were randomized to receive either peripheral-administered CRH (100 µg bolus + 1 µg/kg/h) or placebo (saline), followed by at least a 7-day washout period and assignment to the opposite treatment. Tests encompassed saliva samples, gastric-emptying (GE) testing, body surface gastric mapping (BSGM, Gastric Alimetry; Alimetry) to assess gastric myoelectrical activity with real-time symptom profiling, and a gastric barostat study to assess gastric sensitivity to distention and accommodation. Twenty HVs [13 women, mean age 29.2 ± 5.3 yr, body mass index (BMI) 23.3 ± 3.8 kg/m2] completed GE tests, of which 18 also underwent BSGM measurements during the GE tests. The GE half-time decreased significantly after CRH exposure (65.2 ± 17.4 vs. 78.8 ± 24.5 min, P = 0.02) with significantly increased gastric amplitude [49.7 (34.7-55.6) vs. 31.7 (25.7-51.0) µV, P < 0.01], saliva cortisol levels, and postprandial symptom severity. Eleven HVs also underwent gastric barostat studies on a separate day. However, the thresholds for discomfort during isobaric distensions, gastric compliance, and accommodation did not differ between CRH and placebo.NEW & NOTEWORTHY In healthy volunteers, peripheral corticotropin-releasing hormone (CRH) infusion accelerates gastric-emptying rate and increases postprandial gastric response, accompanied by a rise in symptoms, but does not alter gastric sensitivity or meal-induced accommodation. These findings underscore a significant link between stress and dyspeptic symptoms, with CRH playing a pivotal role in mediating these effects.

Understanding the Conditions Under Which Drugs are Transferred from the Stomach Through the Upper Small Intestine After a High-Calorie, High-Fat Meal.

Information on the conditions under which drugs are transferred from the stomach through the upper small intestine after a high-calorie, high-fat meal is very limited. To simulate the drug presence after disintegration and arrival in the antral region, paracetamol solution and Sporanox® amorphous solid dispersion pellets at two dose levels were administered to the antrum of 8 healthy adults 30 min after administration of a high-calorie, high-fat meal on a crossover basis. The overall median buffer capacity of antral contents was estimated to be 18.0 and 24.0 mmol/ml/ΔpH when titrating with NaOH and HCl, respectively. The corresponding values for the contents of upper the small intestine were 14.0 and 16.8 mmol/ml/ΔpH, respectively. The drug transfer process from the antrum through the upper small intestine occurred with apparent first-order kinetics. The best estimate for the antral emptying half-life was 39min and 45min for paracetamol and itraconazole, respectively, the apparent volume of contents of the upper small intestine was more than double compared with previously reported values in the fasted state, the half-life of drug elimination from the upper small intestine was similar to recent estimates for highly permeable drugs in the fasted state, and the apparent volume of antral contents during the first couple of hours post drug administration was 303mL. Information collected in this study could increase the reliability of in silico and/or in vitro modelling approaches applied in clinical drug development.

Impact of Physicochemical Modifications in Casein Promoted by UV-C on the Peptide Profile of Gastric Digestion and the Transepithelial Transport of Peptides.

Caseins are the main proteins in milk, and their structure and spatial conformation are responsible for their slow digestion rate. The release of bioactive and ß-casomorphin peptides from casein digestion may induce allergic responses during consumption. Spectroscopic techniques were used to observe the structural changes in casein conformation induced by Ultraviolet light irradiation (UV-C). Raman spectroscopy results showed more pronounced peaks at 618 and 640 cm-1 for phenylalanine and tyrosine moieties of the photolyzed micellar casein, respectively, suggesting changes in the micelle structure. The decrease in the intensity of Raman signals for tryptophan and tyrosine corroborates to the UV-C-induced modifications of the micelle structure. Particle size distribution showed a decrease in the average micelle size after 15 min of UV-C exposure, while low-temperature, long-time (LTLT) pasteurization led to the formation of large aggregates, as observed by atomic force microscopy. UV-C did not impact the formation or transport of peptides, as observed by using the Caco-2 cell as a model for peptide absorption. However, the absence of the opioid peptide SRYPSY from κ-casein and only 20% of the concentration of opioid peptide RYLGY were noted. This work demonstrated that UV-C can be utilized to induce the physicochemical modification of dairy products, promoting a higher digestion rate and reducing allergenicity.

The Effect of Dried Ginger (Gan Jiang) on Stomach Energy Metabolism and the Related Mechanism in Rats Based on Metabonomics.

Dried ginger is a commonly used stomachic. Dried ginger is often used as a gastric protector to treat stomach-related diseases. However, the effect of dried ginger on energy metabolism in stomach tissue of rats under physiological condition has not been studied. In this study, different doses of water extract of dried ginger were given to rats for 4 weeks. The activity of Na+ -K+ -ATPase, Ca2+ -Mg2+ -ATPase, SDH (succinate dehydrogenase) enzyme, ATP content, mitochondrial metabolic rate and mitochondrial number in stomach tissue of rats were measured. Analysis of potential biomarkers related to the effect of dried ginger on energy metabolism in stomach tissue of rats by metabonomics, and their metabolic pathways were also analyzed. The results revealed that there was no significant difference in Na+ -K+ -ATPase in high-dose group (GJH), medium-dose group (GJM) and low-dose group (GJL) compared to the Control group. The Ca2+ -Mg2+ -ATPase activity was significantly increased in stomach tissue of GJH group and GJM group, but there were no significant changes in stomach tissue of GJL group. The SDH activity and the ATP levels were significantly increased in stomach tissue of GJH group, GJM group and GJL group. The mitochondrial metabolic rate was significantly increased in GJL group, but there was no significant change in GJM group and was inhibited in GJH group. These effects might be mediated by arginine biosynthesis, glutathione metabolism, arachidonic acid metabolism, glycerophospholipid metabolism, arginine and proline metabolism, purine metabolism pathway.

The dual gastro- and neuroprotective effects of curcumin loaded chitosan nanoparticles against cold restraint stress in rats.

Stress is a condition affecting different body systems. Curcumin (CUR) is a natural compound that has various pharmacological benefits. However, its poor oral bioavailability limits its therapeutic value. This study aimed to formulating curcumin loaded chitosan nanoparticles (CS.CUR.NPs) and investigate its gastroprotective and neuroprotective effects in rats subjected to cold restraint stress (CRS), in reference to conventional oral CUR preparation, and explore its underlying mechanism. Treated groups received either CUR or CS.CUR.NPs (100 mg∕kg) orally for 14 days before exposure to CRS. CRS elicited marked behavioral changes and gastric ulcer accompanied by histopathological abnormalities of the brain and stomach along with elevation of pain score. CUR and CS.CUR.NPs improved stress-induced gastric ulcer, cognitive performance, and pain sensation. Mechanistically, CRS disrupts oxidative and inflammatory status of the brain as manifested by high malondialdehyde and IL-6 and low total antioxidant capacity and IL-10, along with high C-reactive protein level. CRS decreased nuclear factor erythroid 2-related factor2 (Nrf2) and increased nuclear factor-kappa B (NF-κB) expressions. Furthermore, brain levels of unphosphorylated signal transducer and activator of transcription3 (U-STAT3) and glial fibrillary acidic protein (GFAP) were upregulated with stress. CUR and CS.CUR.NPs provided beneficial effects against harmful consequences resulting from stress with superior beneficial effects reported with CS.CUR.NPs. In conclusion, these findings shed light on the neuroprotective effect of CUR and CS.CUR.NPs against stress-induced neurobehavioral and neurochemical deficits and protection against stress-associated gastric ulcer. Moreover, we explored a potential crosslink between neuroinflammation, U-STAT3, NF-κB, and GFAP in brain dysfunction resulted from CRS.

Fucoidan from Sargassum hemiphyllum inhibits infection and inflammation of Helicobacter pylori.

Having infected by Helicobacter pylori, the infection often leads to gastritis, gastric ulcer, or even gastric cancer. The disease is typically treated with antibiotics as they used to effectively inhibit or kill H. pylori, thus reducing the incidence of gastric adenoma and cancer to significant extent. H. pylori, however, has developed drug resistance to many clinically used antibiotics over the years, highlighting the crisis of antibiotic failure during the H. pylori treatment. We report here that the fucoidan from Sargassum hemiphyllum can significantly reduce the infection of H. pylori without developing to drug resistance. Fucoidan appears to be a strong anti-inflammation agent as manifested by the RAW264.7 cell model examination. Fucoidan can prohibit H. pylori adhesion to host cells, thereby reducing the infection rate by 60%, especially in post treatment in the AGS cell model assay. Mechanistically, fucoidan intervenes the adhesion of BabA and AlpA of H. pylori significantly lowering the total count of H. pylori and the level of IL-6 and TNF-α in vivo. These results all converge on the same fact that fucoidan is an effective agent in a position to protect the stomach from the H. pylori infection by reducing both the total count and induced inflammation.

Zuojin Pill attenuates Helicobacter pylori-induced chronic atrophic gastritis in rats and improves gastric epithelial cells function in GES-1 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Zuojin pill (ZJP), a classical Chinese medicine formula, has been widely applied in Chinese clinical practice for the treatment of gastric injury such as acute gastric lesion, acute gastric mucosal injury, chronic unpredictable mild stress, gastroesophageal reflux disease, etc, thereby exerting anti-chronic atrophic gastritis (CAG) effects in traditional Chinese herbal medicine. AIM OF THE STUDY: This study was aimed to explore the therapeutic effects and molecular mechanisms of ZJP on Helicobacter pylori (H. pylori)-induced CAG based on the comprehensive approaches. MATERIALS AND METHODS: Sprague-Dawley rats were infected with H. pylori for 8 weeks to establish CAG model. Then, rats in the ZJP groups received doses of 0.63, 1.26, and 2.52 g/kg ZJP for 4 weeks. Therapeutic effects of ZJP on serum indices and the histopathology of the gastric were analyzed in vivo. Moreover, GES-1 cells were infected with H. pylori to establish gastric epithelial cell injury model in vitro. Cell viability and gastric epithelial cell morphology were detected by a high-content screening (HCS) assay. Furthermore, the relative mRNA and protein expression of JMJD2B/COX-2/VEGF axis and HMGB1/NF-κB signaling pathway in vivo and in vitro were determined by RT-PCR and Western Blotting, respectively. RESULTS: The results showed that the therapeutic effects of ZJP on CAG rats were presented in down-regulation serum biochemical indices and alleviating histological damage of gastric tissue. ZJP could dose-dependently decrease the serum IL-6, MCP-1, PGE2, TNF-α, and VEGF level and significantly improved gastric tissue inflammatory lesions. Besides, ZJP has an effect on increasing cell proliferation of GES-1 cells, ameliorating H. pylori-induced gastric epithelial cell damage. It was found that ZJP has a down-regulating effect on inflammatory reaction and could inhibit the relative mRNA and protein expression of JMJD2B/COX-2/VEGF axis and HMGB1/NF-κB signaling pathway in vivo and in vitro, including JMJD2B, COX-2, VEGF, VEGFR1, and VEGFR2, which in turn reduced the damage of gastric mucosal cells. CONCLUSIONS: The results suggested that ZJP exerts therapeutic effects on H. pylori-induced CAG by inhibiting the JMJD2B/COX-2/VEGF axis and HMGB1/NF-κB signaling pathway. These findings deeply explained why ZJP could be used to treat CAG clinically and clarified its pharmacological effect and potential mechanism in the treatment of CAG.

Formulation of stomach-specific floating microparticles of nizatidine and their radiographic evaluation

Nizatidine is an anti-secretogogue and a gastroprotective drug with a half-life of 1-2 h and is well absorbed in the stomach. This study aimed to optimize the process and develop floating microparticles of nizatidine that are based on low methoxyl pectin. Oil-in-oil dispersion method and Taguchi orthogonal array design were employed, and the prolonged residence time of the microparticles in the stomach was demonstrated. The constraints for independent variables, viz. A-polymer, B-internal solvent volume, C-surfactant, D-stirring rate and E-stirring time were set to generate the experimental runs. Particle size, percentage yield, micromeritic properties, entrapment efficiency, in vitro buoyancy and in vitro release were characterized. Surface morphology, zeta potential, in vitro release kinetics and in vivo floating performance of the optimized formulation was examined. The microparticles were free-flowing, irregular in shape and had a mean particle size distribution of 73-187 µ. Low methoxyl pectin played a predominant role in achieving buoyancy and optimum gastric retention for the modified release of the drug, suggesting Korsmeyer-Peppas model as the possible release mechanism. In vivo radiographic study in rabbits revealed that the drug was retained in the stomach for a period of 6 h. These results indicate that nizatidine floating microparticulate system provides modified drug release for the effective treatment of gastric ulcer

Comparative stomach tissue distribution profiles of four major bio-active components of Radix Astragali in normal and gastric ulcer mice

Numerous studies have demonstrated that Radix Astragali can inhibit gastric ulcers in mice. Anhydrous ethanol (0.01 mL/g) administered to mice by intragastric infusion can induce gastric ulcer injury. This study was performed to compare the stomach tissue distribution profiles of four major bioactive constituents of Radix Astragali(calycosin-7-O-ß-d-glucoside, calycosin, ononin and formononetin) after oral administration of extract of Radix Astragali (ERA)in normal and gastric ulcer mice. The abundance of Radix Astragali constituents was determined using an ultra-pressure liquid chromatograph with a photodiode array detector (UPLC-PDA), after which histograms were drawn. In comparison with normal mice, the contents of calycosin- 7-O-ß-d-glucoside, calycosin, ononin and formononetin in the stomach tissue samples of gastric ulcer mice showed significant differences at the selected time points (P < 0.05).The abundance of each of the four tested constituents in the normal groups was higher than that of the gastric ulcer groups. This study provides an empirical foundation for future studies focused on developing clinical applications of Radix Astragali

Uptake and toxicity of polystyrene micro/nanoplastics in gastric cells: Effects of particle size and surface functionalization.

Toxicity of micro or nanoplastics (MP/NP) in aquatic life is well-documented, however, information about the consequences of exposure to these particles in terrestrial species is scarce. This study was used to evaluate the uptake and/or toxicity of polystyrene MP/NP in human gastric cells, comparing doses, particle sizes (50, 100, 200, 500, 1000 or 5000 nm) and surface functionalization (aminated, carboxylated or non-functionalized). In general, the uptake of 50 nm particles was significantly higher than 1000 nm particles. Among the 50 nm particles, the aminated particles were more avidly taken up by the cells and were cytotoxic at a lower concentration (≥ 7.5 µg/mL) compared to same sized carboxylated or non-functionalized particles (≥ 50 µg/mL). High toxicity of 50 nm aminated particles corresponded well with significantly high rates of apoptosis-necrosis induced by these particles in 4 h (29.2% of total cells) compared to all other particles (≤ 16.8%). The trend of apoptosis-necrosis induction by aminated particles in 4 h was 50 > 5000 > 1000 > 500 > 200 > 100 nm. The 50 nm carboxylated or non-functionalized particles also induced higher levels of apoptosis-necrosis in the cells compared to 100, 1000 and 5000 nm particles with same surface functionalization but longer exposure (24 h) to 50 nm carboxylated or non-functionalized particles significantly (p<0.0001) increased apoptosis-necrosis in the cells. The study demonstrated that the toxicity of MP/NP to gastric cells was dependent on particle size, dose surface functionalization and exposure period.

Efficacy and safety of a thermosensitive hydrogel for endoscopic submucosal dissection: An in vivo swine study.

Injectable thermo-sensitive chitosan hydrogels have recently been developed for the use of submucosal fluids in endoscopic submucosal dissections (ESD). This study aimed to investigate the efficacy and safety of chitosan hydrogels during ESD. Submucosal fluids were administered as follows: 0.9% normal saline (NS), 0.4% hyaluronic acid (HA) and chitosan/ß-glycerophosphate (CS/GP) hydrogel. Each solution was administered twice into the stomach and colon of a pig, with a total of 72 ESD procedures performed on 12 pigs. The injected volume and procedure-related parameters were recorded and analyzed. ESDs that created ulcers after 7 days were histologically compared. All ESD specimens were resected en bloc. The total injected volumes during ESD of the stomach (NS, 16.09±3.27 vs. HA, 11.17±2.32 vs. CS/GP, 9.44±2.33; p<0.001) and colon (NS, 9.17±1.80 vs. HA, 6.67±1.50 vs. CS/GP, 6.75±1.57; p = 0.001) were significantly different. Hydrogel showed significant differences from normal saline in terms of fluid power (mm2/vol; NS, 35.70±9.00 vs. CS/GP 57.48±20.77; p = 0.001) and consumption rate (vol/min; NS, 2.59±0.86 vs. CS/GP, 1.62±0.65; p = 0.013) in the stomach. Histological examination revealed preserved muscularis propria, although the chitosan hydrogel resulted in a partial inflammatory response, with a hypertrophied submucosal layer. Chitosan hydrogel was found to be superior to normal saline, with an efficacy similar to that of hyaluronic acid. Nonetheless, long-term histological changes should be evaluated before clinical implementation.

Multiplexed imaging reveals an IFN-γ-driven inflammatory state in nivolumab-associated gastritis.

Immune checkpoint blockade using PD-1 inhibition is an effective approach for treating a wide variety of cancer subtypes. While lower gastrointestinal (GI) side effects are more common, upper gastrointestinal adverse events are rarely reported. Here, we present a case of nivolumab-associated autoimmune gastritis. To elucidate the immunology underlying this condition, we leverage multiplexed ion beam imaging by time-of-flight (MIBI-TOF) to identify the presence and proportion of infiltrating immune cells from a single section of biopsy specimen. Using MIBI-TOF, we analyze formalin-fixed, paraffin-embedded human gastric tissue with 28 labels simultaneously. Our analyses reveal a gastritis characterized by severe mucosal injury, interferon gamma (IFN-γ)-producing gastric epithelial cells, and mixed inflammation that includes CD8 and CD4 T cell infiltrates with reduced expression of granzyme B and FOXP3, respectively. Here, we provide a comprehensive multiplexed histopathological mapping of gastric tissue, which identifies IFN-γ-producing epithelial cells as possible contributors to the nivolumab-associated gastritis.

Metaplasia of respiratory and digestive tissues in the eastern oyster Crassostrea virginica associated with the Deepwater Horizon oil spill.

Metaplasia is a well documented and deleterious effect of crude oil components on oysters. This reversible transformation of one cell type to another is a common response to petroleum-product exposure in molluscs. It has been shown experimentally in previous work that eastern oysters (Crassostrea virginica) exposed to petroleum products will exhibit metaplasia of digestive tissues. Here we document for the first time that wild adult oysters inhabiting coastal waters in the northern Gulf of Mexico during and in the aftermath of the Deepwater Horizon oil spill (2010) exhibited metaplasia in both ctenidial (respiratory and suspension feeding) and digestive tract tissues at significantly higher frequencies than geographic controls of C. virginica from Chesapeake Bay. Metaplasia included the loss of epithelial cilia, transformations of columnar epithelia, hyperplasia and reduction of ctenidial branches, and vacuolization of digestive tissues. Evidence for a reduction of metaplasia following the oil spill (2010-2013) is suggestive but equivocal.

Protocol for chemically induced murine gastric tumor model.

N-Methyl-N-nitrosourea, an N-nitroso compound converted from dietary nitrite by Helicobacter pylori, causes somatic mutations in epithelial cells and induces gastric premalignancy. Here, we describe a detailed protocol for induction of gastric tumor and analysis of tumor phenotypes in mice. This model can be widely used for studying the initiation and growth of gastric cancer. For complete details on the use and execution of this protocol, please refer to Li et al. (2021).

Gastroprotective Effect of Enteral Nutrition Formula in Mice Injected Subcutaneously with Indomethacin.

We have previously shown that two enteral nutrition formulas suppressed gastric lesions induced by the oral administration of indomethacin (IND) in mice. However, the mechanism of their protective effect is unknown. In this study, the effect of the two enteral nutrition formulas on gastric lesions induced by subcutaneous IND injection was investigated, with the objective of exploring the possibility that they may interact directly with IND in the gastrointestinal tract. Ten-week-old, male, ICR mice were fasted, then orally given either purified water, Mermed® One, or 2-fold diluted Terumeal® 2.0α as enteral nutrition formula (25 mL/kg). IND was injected subcutaneously at 20 mg/kg after 30 min, and the stomach was removed 6 h later and fixed in formalin. The number and area of lesions in the stomachs of mice given enteral nutrition formula was reduced to 56-89% and 34-61%, respectively, compared with the mice given purified water. The time courses of plasma IND concentrations were comparable among the three groups. These results suggested that the effect of these enteral nutrition formulas on gastric lesions did not originate from their direct interaction with IND in the gastrointestinal tract or their effect on the disposition of IND.

Assessment of cellular and molecular metrics for dose selection in an in vivo comet assay: A case study with MDI.

The in vivo comet assay can evaluate the genotoxic potential of a chemical in theoretically any tissue that can be processed to a single cell suspension. This flexibility enables evaluation of point-of-contact tissues using a relevant route of test material administration; however, assessing cytotoxicity is essential for the interpretation of comet results. Histopathological evaluation is routinely utilized to assess cytotoxicity, but temporal- and cell-specific considerations may compromise applicability to the comet assay. In the present study, 1,1'-methylenebis(4-isocyanatobenzene) (4,4'-MDI) was administered to rats for 6 h by nose-only inhalation, and the comet assay was conducted to evaluate genotoxicity in the site-of-contact tissue (bronchoalveolar lavage cells) and distal tissues (liver and glandular stomach). Given the reactive nature of MDI, cellular and molecular metrics at the site-of-contact- including inflammation, macrophage activation, apoptosis/necrosis, and oxidative stress- were used to set appropriate exposure concentrations, in addition to the standard systemic measures of toxicity. In the range-finding study, a concentration of 4 mg/m3 was considered the maximum noninflammatory concentration; hence target concentrations of 2, 5, and 11 mg/m3 were selected for the comet study. In the lung lavage, MDI exposure substantially increased total protein and ß-glucuronidase, along with cellular apoptosis. Although MDI did not increase the comet assay response (% tail DNA) in any of the tissues examined, the positive control (ethyl methanesulfonate, EMS) significantly increased % tail DNA in all tissues. In total, these data indicate that appropriate cellular and molecular measurements may facilitate dose selection to discern cellular status in the comet assay.

The suppressive effect of REVERBs on ghrelin and GOAT transcription in gastric ghrelin-producing cells.

Ghrelin is a multifunctional gut peptide with a unique structure, which is modified by a medium chain fatty acid at the third serine by ghrelin O-acyl transferase (GOAT). It is well known that the major source of plasma ghrelin is the stomach, but the transcriptional regulation of gastric ghrelin and GOAT is incompletely understood. Here, we studied the involvement of the nuclear receptors REV-ERBα and REV-ERBß on ghrelin and GOAT gene expression in vivo and in vitro. Reverse-transcriptase polymerase chain reaction analysis showed that REV-ERBα and REV-ERBß mRNAs were expressed in the stomach and a stomach-derived ghrelin cell line (SG-1 cells). In vivo experiments with mice revealed the circadian rhythm of ghrelin, GOAT, and REV-ERBs. The peak expression of ghrelin and GOAT mRNAs occurred at Zeitgeber time (ZT) 4, whereas that of REV-ERBα and REV-ERBß was observed at ZT8 and ZT12, respectively. Treatment of SG-1 cells with SR9009, a REV-ERB agonist, led to a significant reduction in ghrelin and GOAT mRNA levels. Overexpression of REV-ERBα and REV-ERBß decreased ghrelin and GOAT mRNA levels in SG-1 cells. In contrast, small-interfering RNA (siRNA)-mediated double-knockdown of REV-ERBα and REV-ERBß in SG-1 cells led to the upregulation in the expression of ghrelin and GOAT mRNAs. These results suggest that REV-ERBs suppress ghrelin and GOAT mRNA expression.