Enhancement of Gastric Ulcer Healing and Angiogenesis by Hepatocyte Growth Factor Gene Mediated by Attenuated Salmonella in Rats

Protective and Healing Effects of Ghrelin and Risk of Cancer in the Digestive System

Ghrelin is an endogenous ligand for the ghrelin receptor, previously known as the growth hormone secretagogue receptor. This hormone is mainly produced by endocrine cells present in the gastric mucosa. The ghrelin-producing cells are also present in other organs of the body, mainly in the digestive system, but in much smaller amount. Ghrelin exhibits a broad spectrum of physiological effects, such as stimulation of growth hormone secretion, gastric secretion, gastrointestinal motility, and food intake, as well as regulation of glucose homeostasis and bone formation, and inhibition of inflammatory processes. This review summarizes the recent findings concerning animal and human data showing protective and therapeutic effects of ghrelin in the gut, and also presents the role of growth hormone and insulin-like growth factor-1 in these effects. In addition, the current data on the possible influence of ghrelin on the carcinogenesis, its importance in predicting the risk of developing gastrointestinal malignances, as well as the potential usefulness of ghrelin in the treatment of cancer, have been presented.

Protease Inhibitors Protect Bovine Colostrum or Chicken Egg Growth Factors from Pancreatic Enzyme Digestion in AGS Cells or Colitic Rats

BACKGROUND

Bovine colostrum (BC) and chicken egg contain proteins possessing growth factor activity. Epidermal growth factor (EGF) provides much of the pro-reparative activity within BC. Clinical use of orally administered peptide growth factors is hampered by digestion from pancreatic proteases.

OBJECTIVES

We examined whether adding a protease inhibitor [soybean trypsin inhibitor (SBTI) or ovomucoid] protected bioactivity of BC ± egg or EGF alone against pancreatic digestion using in vitro and in vivo models.

METHODS

BC, egg, or EGF alone or in combination with trypsin inhibitors were tested for proliferative (Alamar blue) activity using human gastric adenocarcinoma (AGS) cells, prior to and after incubation with HCl/pepsin and trypsin/chymotrypsin. Data were analyzed using 2-factor ANOVA. Eight groups (n = 10) of adult female Sprague-Dawley rats (mean: 188.3 ± 0.8 g) received 20 mg/kg/d of BC + egg, 100 μg/d of EGF, 5 mg/d ovomucoid, or 10.8 mg/d SBTI, alone or in combination (in 1 mL 3% NaHCO3) by gavage for 9 d and dextran sodium sulfate (DSS; 5% in drinking water) for the final 7 d. Histology, microscopic damage score, and myeloperoxidase (MPO) were assessed and analyzed using 1-factor ANOVA.

RESULTS

Proliferative activities of BC, egg, or EGF were reduced 40-57% by HCl/pepsin exposure and further reduced 14-24% by chymotrypsin/trypsin. Co-addition of SBTI or ovomucoid truncated the decrease in proliferative bioactivity caused by chymotrypsin/trypsin by 54-100% (P < 0.01). In vivo study showed oral EGF alone or protease inhibitors given alone were ineffective in reducing DSS damage, whereas SBTI with EGF or ovomucoid with BC + egg improved protective effects on weight gain, disease activity score, colonic MPO, and histology damage by 3-4-fold (P < 0.01).

CONCLUSIONS

Studies using AGS, cells, and Sprague-Dawley rats showed the protease inhibitors ovomucoid and SBTI protected BC, egg, and EGF against loss of bioactivity due to pancreatic enzymes and, when given with NaHCO3, enhanced colonic protection against DSS damage.

Formononetin inhibits inflammation and promotes gastric mucosal angiogenesis in gastric ulcer rats through regulating NF-κB signaling pathway

To investigate the effects of formononetin on rats with gastric ulcer and further to explore its possible mechanism. Rats were randomly divided into sham operation group (Sham), model group (Model), omeprazole control group (Omeprazole) and formononetin in different dose groups (FOR-L, FOR-M, FOR-H). Rats model with gastric ulcer were established by 100% glacial acetic acid. Hematoxylin-eosin (H&E) staining was used to observe the pathological morphology of gastric mucosa. Immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) were used to detect the level of inflammatory and angiogenesis related factors. The expressions of nuclear factor kappa-B (NF-κB) signaling pathway-related proteins were detected by western blot. Formononetin and omeprazole could ameliorate the pathological morphology of gastric mucosa in gastric ulcer rats. Compared with Model group, the levels of tumor necrosis factor (TNF)-α, Interleukin (IL)-1β, IL-6, myeloperoxidase (MPO), human endothelin (ET)-1 and p-P65 protein in formononetin treatment and omeprazole groups were significantly decreased (p < 0.05). Moreover, formononetin could increase the content of vascular endothelial growth factor (VEGF), nitric oxide (NO) and the levels of CD34, tight junction proteins (ZO-1 and occludin) and p-IκBα in a dose-dependent manner. Formononetin can ameliorate gastric ulcer in rats by inhibiting inflammation and promoting gastric mucosal angiogenesis, and its mechanism maybe related to NF-κB signaling pathway.

Immunohistochemical Studies of Age-Related Changes in Cell Proliferation and Angiogenesis during the Healing of Acetic Acid-Induced Gastric Ulcers in Rats

Cell proliferation and angiogenesis are of utmost importance for healing to take place. The KI67 and EGFR proteins are markers of cell proliferation, while CD31 and factor VIII are markers of angiogenesis. To elucidate the mechanism responsible for delayed healing of the gastric injury in old age, we analyzed the expression of these markers in rats of different months during the healing of an acetic acid-induced gastric ulcer. Male Wistar rats (aged 3, 6, 12, and 18 months) divided into four groups, according to their ages, formed the experimental animals. Stomach tissue samples were collected on days 3, 7, 14, and 21 after induction for assessment of ulcer healing. The area of gastric mucosa healed was inversely proportional to age. The expression of markers of proliferation (KI67 and EGFR) and angiogenesis (factor VIII and CD31) decreased significantly (p < 0.05) in older rats when compared with younger ones (3 months > six months > 12 months > 18 months) on days 7, 14, and 21 after induction of gastric ulcer. This study revealed that the slower gastric ulcer healing rate in older rats might be due to reduced epithelial cell proliferation and angiogenic activities.

miRNAs in gastrointestinal diseases: can we effectively deliver RNA-based therapeutics orally?

Nucleic acid-based therapeutics are evaluated for their potential of treating a plethora of diseases, including cancer and inflammation. Short nucleic acids, such as miRNAs, have emerged as versatile regulators for gene expression and are studied for therapeutic purposes. However, their inherent instability in vivo following enteral and parenteral administration has prompted the development of novel methodologies for their delivery. Although research on the oral delivery of siRNAs is progressing, with the development and utilization of promising carrier-based methodologies for the treatment of a plethora of gastrointestinal diseases, research on miRNA-based oral therapeutics is lagging behind. In this review, we present the potential role of miRNAs in diseases of the GI tract, and analyze current research and the cardinal features of the novel carrier systems used for nucleic acid oral delivery that can be expanded for oral miRNA administration.

1-Deoxynojirimycin (DNJ) Ameliorates Indomethacin-Induced Gastric Ulcer in Mice by Affecting NF-kappaB Signaling Pathway

Gastric ulcer (GU) is a main threat to public health. 1-Deoxynojirimycin (DNJ) has antioxidant and anti-inflammatory properties and may prevent GU but related mechanism remains unclear. DNJ was extracted from the supernatants of Bacillus subtilis by using ethanol and purified by using CM-Sepharose chromatography. A GU mouse model was induced by indomethacin. The functional role of DNJ in GU mice was explored by measuring the main molecules in the NF-KappaB pathway. After the model establishment, 40 GU mice were evenly assigned into five categories: IG (received vehicle control), LG (10 μg DNJ daily), MG (20 μg DNJ daily), HG (40 μg DNJ daily), and RG (0.5 mg ranitidine daily). Meanwhile, eight healthy mice were assigned as a control group (CG). After 1-month therapy, weight and gastric volume were investigated. The levels of serum inflammatory cytokines (IL-6 and TNF-α), antioxidant indices [superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH)], and oxidant biomarker malondialdehyde (MDA) were examined via ELISA. Meanwhile, inflammatory cytokine (IL-6 and TNF-α) levels, and key molecules (NF-κB p65), cyclooxygenase 1 (COX-1 and COX2) involved in NF-κB pathway, were analyzed by using Western Blot. COX-1 and COX-2 levels were further measured by immunohistochemistry. The effects of DNJ on gastric functions were explored by measuring the changes of Motilin (MOT), Substance P (SP), Somatostatin (SS), and Vasoactive intestinal peptide (VIP) in GU mouse models with ELISA Kits. The results indicated that DNJ prevented indomethacin-caused increase of gastric volume. DNJ improved histopathology of GU mice when compared with the mice from IG group (P < 0.05). DNJ consumption decreased the levels of IL-6 and TNF-α (P < 0.05). DNJ increased antioxidant indices of GU mice by improving the activities of SOD, CAT and reduced GSH, and reduced MDA levels (P < 0.05). DNJ increased the levels of prostaglandin E2, COX-1, COX2, and reduced the levels of and NF-κB p65 (P < 0.05). DNJ showed protection for gastric functions of GU mice by reducing the levels of MOT and SP, and increasing the levels of SS and VIP. DNJ treatment inactivates NF-κB signaling pathway, and increases anti-ulceration ability of the models.