The effect of n-3/n-6 polyunsaturated fatty acids on acute reflux esophagitis in rats

JP-1366: A novel and potent potassium-competitive acid blocker that is effective in the treatment of acid-related diseases

The global prevalence of GERD is substantially increasing each year, and GERD is a chronic disease that reduces the quality of life of patients. The efficacy of conventional drugs is diverse, and most require long-term or lifetime administration; thus, the development of more effective therapeutic agents is needed. Herein, a more effective treatment for GERD was tested. We investigated whether JP-1366 affected gastric H+/K+-ATPase activity and used the Na+/K+-ATPase assay to confirm the selectivity of H+/K+-ATPase inhibition. To clarify the mechanism of enzyme inhibition, JP-1366 and TAK-438 were analyzed by Lineweaver-Burk. Also, we investigated the effects of JP-1366 in various models involving reflux esophagitis. We found that JP-1366 mediates strong, selective, and dose-dependent inhibition of H+/K+-ATPase. We found that JP-1366 significantly suppressed gastric acid secretion in histamine-treated pylorus-ligated rats in a dose-dependent manner. Additionally, we confirmed that JP-1366 inhibited histamine-stimulated gastric acid secretion in the HPD model. JP-1366 exhibited a more than 2-fold higher inhibitory effect on esophageal injury than TAK-438 in GERD lesions and had a more potent inhibitory effect in indomethacin- or aspirin-induced gastric ulcer rat models than TAK-438. Additionally, JP-1366 inhibited gastric ulcers. These results support the possibility that JP-1366 is a good candidate drug for treating acid-related diseases.

Elevated Pro-inflammatory Cytokine Levels in Acute Reflux Esophagitis Are Reduced by 1,25 Dihydroxy Vitamin D3

BACKGROUND/AIM

Gastric acid reflux into the esophagus can cause irritation and inflammation of the esophagus and progress to reflux esophagitis (RE). Vitamin D3 (VitD3) has anti-inflammatory effects and plays an important regulatory role in adaptive and innate immunity. We hypothesized that VitD3 may play a protective role in RE.

MATERIALS AND METHODS

Seventy male Sprague-Dawley rats were used, and acute RE (n=35) or chronic RE (n=35) were surgically induced. The effects of different doses of VitD3 on morphological changes and alteration of pro-inflammatory cytokine levels were examined in the rat models. Western blot analysis was performed to determine protein expression levels of IL-1β, IL-6, and IL-8 in esophageal tissues. Serum levels of VitD3 and calcium were determined using enzyme-linked immunosorbent assays.

RESULTS

The protein expression of pro-inflammatory cytokines IL-1β, IL-6, and IL-8 was found significantly increased in RE. VitD3 treatment significantly reduced the levels of these pro-inflammatory cytokines in both the low-dose and high-dose VitD3 groups compared to control groups in acute RE, but not chronic RE. Macrographic and histopathological examination revealed various degrees of esophageal impairment in rats following surgical induction of acute or chronic RE in rats. These impairments were not improved by VitD3. Morphological grading of esophageal mucosa showed no significant differences between acute and chronic RE. Elevated serum levels of calcium were observed after VitD3 treatment.

CONCLUSION

IL-1β, IL-6, and IL-8 levels were significantly elevated in RE. The abnormal increase in these important pro-inflammatory cytokines was suppressed by VitD3 in the rat models of acute RE. These novel findings suggest a potential protective role of VitD3 in early-stage RE.

Resolvin D1 attenuates acid-induced DNA damage in esophageal epithelial cells and rat models of acid reflux

The role of resolvin D1 (RvD1) in gastroesophageal reflux disease (GERD) remains largely unknown. Here, we investigated the potential role of RvD1 in acid-induced DNA damage in esophageal epithelial cells, patients with refractory GERD and a rat model of acid reflux. Weak acid exposure induced longer comet tails, reactive oxygen species (ROS) generation, oxidative DNA damage and DNA double-strand breaks (DSBs) in cells and RvD1 (0.1 μM) blocked all these effects. Mechanistic analyses showed that apart from ROS-reducing effects, RvD1 possessed a strong capacity to promote DNA damage repair, augmenting cell cycle checkpoint activity and DSB repair by modulating phosphatase and tensin homolog (PTEN) in cells. We also detected the surface expression of formyl peptide receptor 2 (FPR2), a receptor for RvD1, in the esophageal epithelial cells, and inhibition of FPR2 abrogated the protective effects of RvD1 on cells. Furthermore, a positive correlation between RvD1 and PTEN was observed predominantly in the esophageal epithelium from patients with refractory GERD (r = 0.67, P < 0.05). Additionally, RvD1 administration upregulated PTEN, suppressed DNA DSBs and alleviated microscopic damage in the rat model of gastric reflux. FPR2 gene silencing abolished the therapeutic effects of RvD1 on the rat model. Taken together, RvD1 binding to FPR2 protects the esophageal epithelium from acid reflux-induced DNA damage via a mechanism involving the inhibition of ROS production and facilitation of DSB repair. These findings support RvD1 as a promising approach that may be valuable for the treatment of GERD.

Protective Effects of Inflammation of Curcumae Longae Rhizoma 30% EtOH Extract on Acute Reflux Esophagitis Rats

Gastroesophageal reflux disease (GERD) is induced by the reflux of stomach contents or gastric acid, pepsin into the esophagus for prolonged periods of time due to defection of the lower esophageal sphincter. Reflux esophagitis is a disease found in less than 50% of GERD patients. This study is aimed at evaluating the protective effect of Curcumae longae Rhizoma 30% EtOH extract (CLR) in acute reflux esophagitis (ARE) rats. CLR measured antioxidant activity through in vitro experiments. Based on the results, we performed experiments in vivo. Before 90 min ARE induction, CLR was administered orally by concentration. ARE was derived by linking the metastatic junction between pylorus and forestomach and corpus in Sprague-Dawley rats. And rats were sacrificed 5 h after surgery. We analyzed the expression of antioxidant and inflammatory-related markers by western blot and observed the production of alanine aminotransferase (ALT), aspartate aminotransferase (AST), reactive oxygen species (ROS), peroxynitrite (ONOO⁻), and thiobarbituric acid reactive substance (TBARS). The administration of CLR reduced esophagus tissue damage in rats with acute reflux esophagitis and decreased the elevated ALT, AST, ROS, ONOO⁻, and TBARS. In addition, CLR effectively increased antioxidant-related factors and reduced inflammatory protein. Overall, these results suggest that CLR would be used as a therapeutic material in protection and treatment for ARE. Overall, CLR treatment informed that markedly ameliorated inactivation of NF-κB led to the inhibition of the expressions of proinflammatory proteins. These results suggest that CLR would be used as a therapeutic material in protection and treatment for ARE.

Low n-6/n-3 PUFA ratio improves inflammation and myocardial ischemic reperfusion injury

This study investigated the potential effect of n-6/n-3 polyunsaturated fatty acids (PUFA) on inflammation and myocardial ischemic reperfusion injury (MIRI) in rats, together with the underlying protective mechanisms, and screen out most effective ratio of n-6/n-3 within limits. The rats with pre-infarct treatment were distributed among 5 groups according to the n-6/n-3 ratio (36:1; 1:1, 5:1, 10:1, 50:1); for the post-infarct treatment, the rats were distributed among 6 groups, including the control group (36:1) which was subjected to a sham procedure; the model group (36:1); and 4 test groups (n-6/n-3 ratio: 1:1, 5:1, 10:1, 50:1). All of the rats were fed a purple perilla seed oil and safflower oil-based fatty emulsion. The serum levels of monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α were determined using enzyme-linked immunosorbent assay. Staining with triphenyl tetrazolium chloride, hematoxylin and eosin, or Masson's trichrome was performed for histological examination. Cardiomyocyte apoptosis was examined by TUNEL assay. Western blotting was performed to examine the expression levels of apoptosis-related proteins and signaling pathway proteins. Our data indicate that in both the pre-infarct treatment and post-infarct treatment, low ratios of n-6/n-3 PUFAs significantly inhibited the levels of serum inflammatory factors, the infarct size of MIRI rats, number of cardiomyocytes undergoing apoptosis, and the expression levels of caspase-3, Bcl-2, and Bax in the MIRI group. Thus a low ratio of n-6/n-3 PUFAs ameliorates inflammation and myocardial ischemic reperfusion injury.

Omega-3 Polyunsaturated Fatty Acids and Their Bioactive Metabolites in Gastrointestinal Malignancies Related to Unresolved Inflammation. A Review

Chronic inflammation takes part in the pathogenesis of some malignancies of the gastrointestinal tract including colorectal (CRC), gastric, and esophageal cancers. The use of ω3 polyunsaturated fatty acid (ω3-PUFA) supplements for chemoprevention or adjuvant therapy of gastrointestinal cancers is being investigated in recent years. Most evidence has been reported in CRC, although their protective role has also been reported for Helicobacter pylori-induced gastric cancer or Barrett’s esophagus-derived adenocarcinoma. Studies based on ω3-PUFA supplementation in animal models of familial adenomatous polyposis (FAP) and CRC revealed positive effects on cancer prevention, reducing the number and size of tumors, down-regulating arachidonic acid-derived eicosanoids, upregulating anti-oxidant enzymes, and reducing lipid peroxidation, whereas contradictory results have been found in induced colitis and colitis-associated cancer. Beneficial effects have also been found in FAP and ulcerative colitis patients. Of special interest is their positive effect as adjuvants on radio- and chemo-sensitivity, specificity, and prevention of treatment complications. Some controversial results obtained in CRC might be justified by different dietary sources, extraction and preparation procedures of ω3-PUFAs, difficulties on filling out food questionnaires, daily dose and type of PUFAs, adenoma subtype, location of CRC, sex differences, and genetic factors. Studies using animal models of inflammatory bowel disease have confirmed that exogenous administration of active metabolites derived from PUFAs called pro-resolving mediators like lipoxin A4, arachidonic acid-derived, resolvins derived from eicosapentaenoic (EPA), docosahexaenoic (DHA), and docosapentaenoic (DPA) acids as well as maresin 1 and protectins DHA- and DPA-derived improve disease and inflammatory outcomes without causing immunosuppression or other side effects.

Maternal Micronutrients, Omega-3 Fatty Acids and Gene Expression of Angiogenic and Inflammatory Markers in Pregnancy Induced Hypertension Rats

BACKGROUND AND AIMS

Preeclampsia is a disorder of pregnancy and is associated with inflammation and altered angiogenesis. The present study examines the effect of micronutrient and omega-3 fatty acid supplementation (individual, as well as combined) on genes involved in inflammation and angiogenesis, as well as global DNA methylation levels in a pregnancy induced hypertension (PIH) rat model.

METHODS

Pregnant Wistar rats were randomly assigned to six dietary groups: control, PIH (Pregnancy induced hypertension) Induced; PIH Induced with micronutrient supplements with vitamin B₁₂ (PIHB), folate (PIHF), omega-3 fatty acid (PIHO), and combined supplementation (PIHC) (micronutrients and omega-3 fatty acids). Half the dams were dissected on 20 d of gestation to collect placental tissue, and half were allowed to deliver normally on 22 d of gestation and were assigned to a postnatal control diet. The offspring were dissected at 3 month of age.

RESULTS

PIH induction increased the mRNA levels of the pro inflammatory cytokine IL-6 (p <0.01), while lowering the placental anti inflammatory cytokine IL-10 (p <0.05) at d20 of gestation. It also increased the expression of TNF-α (p <0.05) in the liver of 3 month old offspring. The combined supplementation of folic acid, vitamin B₁₂ and omega-3 fatty acids improved placental IL-10 levels and decreased TNF-α levels in offspring livers.

CONCLUSION

Our data indicate that a combined supplementation of vitamin B₁₂, folic acid and omega-3 fatty acid was useful for the better management of preeclampsia in an animal model.

A novel murine model of esophageal nonerosive reflux disease: from inflammation to impairment in mucosal integrity

Nonerosive reflux disease (NERD) is a highly prevalent phenotype of the gastroesophageal reflux disease. In this study, we developed a novel murine model of NERD in mice with microscopic inflammation and impairment in the epithelial esophageal barrier. Female Swiss mice were subjected to the following surgical procedure: the transitional region between the forestomach and the glandular portion of the stomach was ligated, and a nontoxic ring was placed around the duodenum near the pylorus. The control group underwent sham surgery. The animals were euthanized at 1, 3, 7, and 14 days after surgery. Survival and body weight were monitored daily. Esophageal wet weight, macroscopic lesion, histopathological alterations, myeloperoxidase (MPO) activity, cytokine levels, transepithelial electrical resistance (TEER), and mucosal permeability were evaluated. The survival rate was 78% at 14 days, with mild loss in body weight. Surgery did not induce erosive esophagitis but instead induced microscopic inflammation and increased esophageal wet weight, IL-6, keratinocyte-derived cytokine (KC) levels, and MPO activity with maximal peak between 3 and 7 days and resolution at 14 days postsurgery. Epithelial esophageal barrier was evaluated in operated mice at 7 and 14 days postsurgery; a decrease in TEER and increase in the esophageal epithelial permeability were observed compared with the sham-operated group. In addition, the inhibition of acid secretion with omeprazole significantly prevented the esophageal inflammation and impairment of barrier function at 7 days postsurgery. Thus we established a novel experimental model of NERD in mice, which can contribute to understanding the pathophysiological events associated with NERD.NEW & NOTEWORTHY In this study, we standardized an experimental model of nonerosive reflux disease (NERD) in mice. This model involves an acute inflammatory response followed by impaired esophageal mucosal integrity, even in the absence of inflammation. Thus this model can serve for evaluation of pathophysiological aspects of NERD and open new perspectives for therapeutic strategies for patients with this disorder.

Antineoplastic effects of clove buds (Syzygium aromaticum L.) in the model of breast carcinoma

It is supposed that plant functional foods, rich in phytochemicals, may potentially have preventive effects in carcinogenesis. In this study, the anticancer effects of cloves in the in vivo and in vitro mammary carcinoma model were assessed. Dried flower buds of cloves (CLOs) were used at two concentrations of 0.1% and 1% through diet during 13 weeks after the application of chemocarcinogen. After autopsy, histopathological and immunohistochemical analyses of rat mammary carcinomas were performed. Moreover, in vitro evaluation using MCF‐7 cells was carried out. Dietary administered CLO caused the dose‐dependent decrease in tumour frequency by 47.5% and 58.5% when compared to control. Analysis of carcinoma cells in animals showed bcl‐2, Ki67, VEGFA, CD24 and CD44 expression decrease and Bax, caspase‐3 and ALDH1 expression increase after high‐dose CLO administration. MDA levels were substantially decreased in rat carcinomas in both CLO groups. The evaluation of histone modifications revealed increase in lysine trimethylations and acetylations (H4K20me3, H4K16ac) in carcinomas after CLO administration. TIMP3 promoter methylation levels of CpG3, CpG4, CpG5 islands were altered in treated cancer cells. An increase in total RASSF1A promoter methylation (three CpG sites) in CLO 1 group was found. In vitro studies showed antiproliferative and pro‐apoptotic effects of CLO extract in MCF‐7 cells (analyses of cytotoxicity, Brdu, cell cycle, annexin V/PI, caspase‐7, Bcl‐2 and mitochondrial membrane potential). This study showed a significant anticancer effect of clove buds in the mammary carcinoma model in vivo and in vitro.