Non-Steroidal Anti-Inflammatory Drugs and Gastric DNA Synthesis

In vitro incubation of endoscopic gastric antral biopsy specimens with tritiated thymidine, with confirmatory autoradiography, was used to assess gastric epithelial cell turnover in man and to investigate the effects of chronic administration of non-steroidal anti-inflammatory drugs (NSAIDs). In the absence of NSAID administration, macroscopic erosions and ulceration in the antrum were associated with enhanced gastric epithelial cell proliferation. In patients taking NSAIDs erosions occurred without a compensatory increase in epithelial cell DNA synthesis. The failure to respond to injury by enhancing epithelial cell proliferation is likely to be an important factor in NSAID-induced gastric damage and supports a role for prostaglandins in enhancing mucosal repair by increasing epithelial cell generation.     

Non-steroidal anti-inflammatory drugs and gastric DNA synthesis

In vitro incubation of endoscopic gastric antral biopsy specimens with tritiated thymidine, with confirmatory autoradiography, was used to assess gastric epithelial cell turnover in man and to investigate the effects of chronic administration of non-steroidal anti-inflammatory drugs (NSAIDs). In the absence of NSAID administration, macroscopic erosions and ulceration in the antrum were associated with enhanced gastric epithelial cell proliferation. In patients taking NSAIDs erosions occurred without a compensatory increase in epithelial cell DNA synthesis. The failure to respond to injury by enhancing epithelial cell proliferation is likely to be an important factor in NSAID-induced gastric damage and supports a role for prostaglandins in enhancing mucosal repair by increasing epithelial cell generation.     

Proliferation and apoptosis in gastric antral epithelial cells of patients infected with Helicobacter pylori

We measured cell proliferation and apoptosis in the antral epithelial cells of Helicobacter pylori-infected and H. pylori-uninfected persons, and examined these processes in relation to diagnosis and the histologic parameters of inflammation to investigate their role in cellular turnover in diseases of the upper gastrointestinal tract. The subjects were: 25 patients with antral gastric cancers, 20 with antral gastric ulcers, 18 with duodenal ulcers, and 28 with chronic gastritis, and 4 subjects with normal gastric mucosa. Seventy-two subjects were infected with H. pylori, and 23 subjects, including the 4 with normal gastric mucosa, were uninfected. H. pylori infection was associated with increased apoptosis and cell proliferation in the gastric mucosa, which correlated with the degree of acute inflammation and the density of H. pylori, and these latter two factors correlated with each other. Intestinal metaplasia and glandular atrophy were significantly higher in gastric cancers and gastric ulcers than in duodenal ulcers. Cell proliferation was significantly lower in gastric cancers than in gastric ulcers, but the apoptotic count did not show a significant differenence between these diseases. This decreased proliferation in the adjacent mucosa in gastric cancers compared with findings in the other diseases is thought to be closely related to the relatively decreased acute inflammation, which may, partly, contribute to glandular atrophy in the adjacent mucosa of gastric cancer. Received: April 26, 1999 / Accepted: October 22, 1999     

Gastric ulcer treatment with intravenous human epidermal growth factor: A double-blind controlled clinical study

Abstract We introduced a double-blind controlled clinical study to compare intravenous human epidermal growth factor (hEGF) to cetraxate hydrochloride (CH), an antiulcer drug, for their healing effect on gastric ulcers. We also prospected an oral use of EGF on the basis of our experimental evidence. In the clinical trial, the rate of ulcer healing within 8 weeks was 77.9% (67/86) in patients receiving 6 μg EGF intravenously twice a week, being significantly greater than 51.7% (45/87) in those given CH. Taking together all aspects assessed including the healing rate, pain relief, blood examination and adverse reactions, we judged the hEGF to be a useful and safe antiulcer drug. In rats, 50 μg/kg mouse EGF (mEGF) and 2% hydroxypropyl cellulose (HPC) or 1.0 g/kg sucralfate given by gastric intubation significantly raised the residual mEGF levels in both gastric luminal content (HPC: x 30; sucralfate: x 300 as high as those in EGF alone) and tissue (HPC: x 60; sucralfate: x 100). In addition, the combined treatments significantly promoted healing of rat gastric ulcers whereas each agent alone had no significant effect as compared with control (saline). This indicated the beneficial effect on ulcers of oral administration of EGF with agents allowing it to remain at high levels in the stomach, whereas most reports suggested less effect of oral EGF on healing of gastroduodenal ulcers. Subsequent to the clinical study, evaluation of oral use of EGF may be expected as the next step in the treatment of ulcers. The experimental evidence above would possibly be a guide for such trial.     

Effect of chronic cimetidine ingestion on fundic and antral epithelial proliferation in the rat

Recent reports of the association of cimetidine treatment with the development of gastric carcinoma stimulated us to study the effect of chronic cimetidine ingestion on epithelial proliferation in the stomach of male Wistar/Lewis rats. One group of rats received cimetidine in the drinking water to deliver 150–200 mg/kg/day. Control rats received plain water. To label proliferating cells, the rats were injected by tail vein with tritiated thymidine 1 hr before sacrifice at 1, 6, and 12 months. Sections of fundus and antrum were processed for light autoradiography. We found no histological evidence for malignant change and no effect on the measurements of epithelial proliferation by cimetidine in either fundus or antrum at any of the times studied, with the possible exception of an upward shift in the distribution of labeled cells within the proliferative zone of the fundus after 6 months. Thus, under the conditions of our experiments we have been unable to identify an effect of cimetidine on epithelial proliferation which would implicate it as a chemical carcinogen.     

Helicobacter pylori infection delays the healing of acetic acid-induced gastric ulcer in Japanese monkeys

To clarify the relationship between Helicobacter pylori and the healing of gastric ulcers, we investigated the healing of acetic acid-induced gastric ulcers in the antral mucosa of Japanese monkeys (n=5) infected with H. pylori and in control monkeys without H. pylori infection (n=6). Using H. pylori-infected Japanese monkeys as an experimental model, gastric ulcers were induced endoscopically with acetic acid. Healing of ulcers and factors that influenced healing were studied. Continuous colonization with H. pylori was confirmed in the infected group throughout the observation period; no H. pylori were isolated from the gastric mucosa of the control group. White scarring was not observed in any infected monkeys 4 weeks after ulcer formation, but was observed in one (20%) of five monkeys at 6 weeks and in all five monkeys eight weeks after ulcer formation. In the control group, white scarring was observed in one (16.7%) of six monkeys at 4 weeks and in six monkeys at 6 (P< 0.01 vs infected group) and 8 weeks. The ammonia concentration of the gastric secretions and the grade of inflammation were significantly increased in the H. pylori-infected group compared with the control group (P< 0.01 and P< 0.001, respectively). The volume of intracellular PAS-positive substance was decreased (P< 0.025–0.01) at the ulcer margin in the infected group compared with the ulcer margin in the control group. The proliferation of gastric epithelial cells was markedly accelerated at the ulcer margin in the infected group compared with the ulcer margin in control group (P< 0.025–0.01). Our results strongly suggest that H. pylori infection delays the healing of gastric ulcers.     

Helicobacter pylori infection accelerates human gastric mucosal cell proliferation

Helicobacter pylori causes chronic atrophic gastritis and intestinal type gastric cancer arises against a background of atrophic gastritis. Increased proliferation of epithelial cells is an important indicator of increased risk for gastric adenocarcinoma. We investigated gastric mucosal cell proliferation inH. pylori-associated gastritis and the effect of eradication therapy on this proliferation in 45 patients endoscopically diagnosed (31 with persistent eradication and 14 in whomH. pylori) recurred.H. pylori status was determined by culture and histology in biopsied specimens from the gastric antrum and corpus. Eradication of the infection was defined as reversal to negative on both tests. In vitro Ki-67 immunostaining of endoscopic biopsy specimens was used to measure mucosal cell proliferation inH. pylori-associated gastritis before and after therapy. The proliferative zone was defined as the distance of Ki-67-positive gastric epithelial cells between the highest and the lowest cells. In patients in whomH. pylori was eradicated, cell proliferation in both the antral and corpus mucosa had decreased 4 weeks after completion of the eradication therapy (P<0.01,P<0.001), and 6 months later, it had markedly decreased (P<0.05,P<0.05) and returned to normal. In patients in whomH. pylori recurred, only antral epithelial cell proliferation was reduced 4 weeks after eradication therapy, but whenH. pylori recurred, determined by culture and histology, cell proliferation level was the same as that before eradication. These results suggest thatH. pylori infection accelerates cell proliferation in gastric mucosa and may play a causal role in the chain of events leading to gastric carcinoma.     

EP4 agonist alleviates indomethacin-induced gastric lesions and promotes chronic gastric ulcer healing

AIM: To investigate EP4-selective agonist effect on indomethacin-induced gastric lesions and on the spontaneous healing of chronic gastric ulcers. METHODS: In a mouse model of gastric bleeding with high dose of indomethacin (20 mg/kg), an EP4-selective agonist was administered orally. Stomach lesions and gastric mucous regeneration were monitored. In a mouse model of chronic gastric ulcer induced by acetic acid, EP4 agonist effect on the healing of chronic gastric ulcer was evaluated in the presence or absence of low dose indomethacin (3 mg/kg). In cultured human gastric mucous cells, EP4 agonist effect on indomethacininduced apoptosis was assessed by flow cytometry. RESULTS: The EP4-selective agonist reduced high dose indomethacin-induced acute hemorrhagic damage and promoted mucous epithelial regeneration. Low-dose indomethacin aggravated ulcer bleeding and inflammation, and delayed the healing of the established chronic gastric ulcer. The EP4 agonist, when applied locally, not only offset indomethacin-induced gastric bleeding and inflammation, but also accelerated ulcer healing. In the absence of indomethacin, the EP4 agonist even accelerated chronic gastric ulcer healing and suppressed inflammatory cell infiltration in the granulation tissue. In vitro , the EP4 agonist protected human gastric mucous cells from indomethacin-induced apoptosis. CONCLUSION: EP4-selective agonist may prevent indomethacin-induced gastric lesions and promote healing of existing and indomethacin-aggravated gastric ulcers, via promoting proliferation and survival of mucous epithelial cells.     

Effect of sialoadenectomy and synthetic human urogastrone on healing of chronic gastric ulcers in rats.

The effect of extirpation of the submandibular glands, an exocrine organ for epidermal growth factor/urogastrone (EGF/URO), and the effect of oral administration of synthetic human (EGF/URO) on healing of chronic gastric ulcers in rats has been investigated. Removal of the submandibular glands delayed healing of chronic gastric ulcers when examined after 50, 100, and 200 days. Oral administration of synthetic human EGF/URO stimulated gastric ulcer healing when examined after 25 and 50 days of treatment. The effect of synthetic human EGF/URO was comparable with that of cimetidine. The combined administration of synthetic human EGF/URO and cimetidine further increased healing of gastric ulcers compared with administration of each substance. Neither synthetic human EGF/URO, nor removal of the submandibular glands had any influence on gastric acid secretion. This study showed that the submandibular glands influence healing of chronic gastric ulcers and suggest that EGF/URO participate in healing of chronic gastric ulcers in rats.     

Cell proliferation in the gastric epithelium of the ulcer rat

OBJECTIVE: Cell division is brisk in the ulcer margin and many of the new cells will migrate over and cover the ulcer bed. The aim of this study was to determine how agents that promote or delay gastric ulcer healing influence cell proliferation in the gastric epithelium. MATERIAL AND METHODS: Acetic acid ulcers were produced in the rat gastric corpus; non-ulcer rats served as controls. All rats were given a continuous infusion of (3)H-thymidine. Some rats were also given gastrin or indomethacin, or infected with Helicobacter pylori. The rats were killed after 1, 2, 6 or 13 days, and the ulcer margin and undamaged corpus were excised for determination of labeling index (LI) by autoradiography. Antrum, duodenum and colon were also studied. Silver grain counting was carried out in some groups. RESULTS: LI in the ulcer margin grew exponentially, reaching 84% after 6 days; gastrin increased, and indomethacin decreased LI significantly. In 6-day ulcer rats that were given 3H-thymidine only during the first day LI was 5%, while in those given 3H-thymidine only during the last day LI was 27%. LI and silver grain counting results indicated that during the first 6 days of healing the epithelial cells in the ulcer margin divide twice. In the undamaged epithelium of the 1-day ulcer rats LI was 相似文献   

Influence of the prostaglandin E1 analogue Rioprostil on the human gastric mucosa

Ten healthy volunteers received the prostaglandin E1 analogue Rioprostil 300 micrograms b.i.d. for 1 week. Endoscopically obtained biopsies were investigated with tritiated thymidine and autoradiography to determine the rate of cell proliferation and with a texture-analyzing system to measure the intracellular amount of mucus in the epithelial cells. Rioprostil did not alter the tritiated thymidine labeling index in the antral area but did significantly depress it in the fundic area. The mucus content was unchanged in the antrum but was significantly increased in the fundus. These observations indicate that Rioprostil given orally causes an enhanced cell maturation in the fundic area as well as an increased intracellular mucus content. Rioprostil seems to have no influence on the human antral area.     

REFRACTORY GASTRIC ANTRAL ULCER OF UNKNOWN ETIOLOGY

We report a Helicobacter pylori‐negative patient with multiple gastric antral ulcers of unknown etiology and without a history of taking non‐steroidal anti‐inflammatory drugs (NSAIDs). The patient was a 68‐year‐old woman, and her serum gastrin and pepsinogen levels were within normal limits. The antral ulcers were refractory to treatment with a proton pump inhibitor (PPI) or an H2 receptor antagonist alone. However, since nocturnal gastric acid breakthrough was observed, both drugs were given in combination, which resulted in the healing of the ulcers.     

Does Co-Prescription of Sucralfate with Ranitidine Therapy Enhance the Healing of Gastric Ulcers?

It has been suggested that the co-administration of ranitidine and sucralfate may enhance peptic ulcer healing more than administration of either drug alone. This study compared the frequency of healing of gastric ulcers treated with either ranitidine 300 mg nocte plus sucralfate 1 g tds or with ranitidine 300 mg nocte plus placebo. Patients (n = 259) were treated initially for 4 wk, and this period was extended to 8 wk for those patients whose ulcers had not healed. Ulcer healing and patient symptom data were assessed at 4 and 8 wk, whereas patients recorded the presence of ulcer pain on a daily basis. Ulcer healing rates were 63% and 66% at 4 wk, and were 93% and 91 % at 8 wk, in the ranitidine-plus-sucralfate group and the ranitidine-plus-placebo group, respectively. Both treatments were equally effective in relieving symptoms. Thus, combination therapy with sucralfate provided no additional benefit over treatment with ranitidine alone.     

Randomised study of the influence of non-steroidal anti-inflammatory drugs on the treatment of peptic ulcer in patients with rheumatic disease.

Sixty-seven patients with rheumatic disease, treated with non-steroidal anti-inflammatory drugs (NSAIDs), entered a controlled trial with a diagnosis of duodenal (n = 51), gastric (n = 14), or gastric and duodenal (n = 2) ulcers. The main objectives of the study were a comparison of ranitidine and sucralfate in ulcer treatment, and to observe the influence of continued NSAID administration during peptic ulcer therapy. Ulcers healed within nine weeks in 52 patients. The mean healing time was similar in 27 patients given ranitidine 150 mg bd (4.9 weeks) and 25 patients given sucralfate 1 g qid (4.6 weeks). In patients with unhealed ulcers after nine weeks of treatment, healing was obtained in seven after further therapy for 3-9 weeks. Of the 30 patients who continued NSAIDs during treatment with either ranitidine or sucralfate, 23 ulcers healed (mean healing time: 5.0 weeks). Of 32 patients in whom NSAIDs were stopped, ulcer healing was documented in 29 (mean healing time: 4.6 weeks). The difference in healing rates was not statistically significant (p greater than 0.10). The outcome of ulcer treatment did not differ in patients with rheumatoid arthritis and patients suffering from osteoarthritis. During a 12 month follow up 14 symptomatic ulcer recurrences were recorded.     

Impairment of Gastric Ulcer Healing by Alendronate,a Nitrogen-Containing Bisphosphonate,in Rats

Bisphosphonates such as alendronate have been developed as antiresorptive agents capable of treating diseases related to bone remodeling. In the present study, we examined the effect of alendronate on the healing of acetic acid-induced gastric ulcers in rats and investigated the mechanism involved in this action both in vivo and in vitro using the rat gastric epithelial cell line (RGM1). Acetic acid-induced gastric ulcers healed spontaneously, with up-regulation of COX-2/prostaglandin E₂ production as well as expression of vascular endothelium-derived growth factor (VEGF) and basic fibroblast growth factor (bFGF) in ulcerated mucosa. The healing of ulcers was impaired by indomethacin (2 mg/kg, s.c.) or alendronate (60 mg/kg, p.o.) given once daily for 7 days, starting 3 days after acid application. Indomethacin, but not alendronate, inhibited mucosal prostaglandin E₂ production. Alendronate as well as indomethacin decreased the protein expression of both VEGF and bFGF in ulcerated mucosa, resulting in a reduction of angiogenesis in the ulcer base. Supplementation of recombinant bFGF significantly reverted the delay in ulcer healing caused by alendronate. On the other hand, the size of cell-free areas in RGM1 cells in vitro decreased with time after wound induction, and this process was promoted by epidermal growth factor (EGF; 10 ng/ml). Co-incubation with alendronate (1 mM) did not affect the spontaneous healing but significantly suppressed the accelerated wound healing caused by EGF. These results suggest that alendronate impairs the healing of gastric ulcers in rats, and this effect may be related to down-regulation of VEGF and bFGF, the important growth factors for vascularization/granulation, as well as suppression of the stimulatory action of EGF on epithelial proliferation/migration.     

Fibroblast growth factor in gastroprotection and ulcer healing: interaction with sucralfate.

The study was designed to determine the gastroprotective and ulcer healing efficacy of basic transforming growth factor (bFGF) and to assess whether this peptide contributes to the action of sucralfate on the rat stomach. Application of human recombinant bFGF (1-100 micrograms/kg/hour subcutaneously) failed to affect the formation of acute gastric lesions induced by 100% ethanol and acidified aspirin but reduced the stress induced by gastric lesions. Sucralfate (100-200 mg/kg given orally) protected gastric mucosa against the ethanol, aspirin, and stress induced acute gastric lesions but the addition of bFGF (100 micrograms/kg subcutaneously or intragastrically) failed to affect sucralfate induced protection against ethanol or aspirin but increased that against stress. Administration of bFGF (3-300 micrograms/kg/day) by an intragastric or an intraperitoneal route or sucralfate (400 mg/kg/day) orally to rats with acetic acid induced gastric ulcers, enhanced the healing rate of these ulcers during seven day treatment in a dose dependent manner. This was accompanied by a pronounced increase in the number of capillaries and myofibroblasts and in DNA synthesis and DNA and RNA concentrations in the granulation tissue in the ulcer area. [125I]bFGF (1 microCi) applied subcutaneously or intragastrically accumulated in two to threefold higher amounts in the ulcer area than in the intact mucosa, particularly in rats treated with sucralfate. Concurrent treatment with indomethacin (2 mg/kg intraperitoneally) delayed ulcer healing and reduced the binding of labelled bFGF to the ulcer area, angiogenesis, and DNA synthesis by sucralfate. Addition of [125I]bFGF to sucralfate at various pHs resulted in the coprecipitation of bFGF by sucralfate in a pH dependent manner from about 10% at pH 7.0 to 90% at pH 1.5. Thus bFGF shows little protective activity and is not essential for gastroprotection afforded by sucralfate but plays an important part in healing of gastric ulcers possibly due to its growth promoting and angiogenic actions.     

Effects of NC-1300, a gastric proton pump inhibitor,on healing of acetic acid-induced gastric ulcers in rats

Effects of NC-1300 (a gastric proton pump inhibitor) on healing of experimental chronic gastric ulcers induced in rats were studied. Gastric ulcers were induced by the submucosal injection of 20% acetic acid (0.03 ml) into the antral-oxyntic border of the anterior wall of male Donryu rats (260–280 g). The healing of acetic acid ulcers was delayed by the daily subcutaneous administration of indomethacin (1 mg/kg) for two or four weeks after ulceration. Aggravation of healed ulcers was evoked by subcutaneous administration of indomethacin (1 mg/kg) once daily for four weeks to rats with four-week-old ulcers. Oral administration of NC-1300 (10, 30, or 100 mg/kg) once daily for two or four weeks after ulceration dose-dependently accelerated both natural and delayed healing of acetic acid ulcers. When the period of administration was extended from two to four weeks, the ED₅₀ values (the dose reducing the ulcerated area by 50%) were decreased from 36.5 to 13.5 mg/ kg in natural healing and from 76.0 to 23.0 mg/kg in delayed healing. Aggravation of four-week-old ulcers by indomethacin was significantly prevented by daily administration of NC-1300 (30 or 100 mg/kg) for four weeks. Acetic acid ulcers that were healed with NC-1300 given for four weeks after ulceration remained healed for four to eight weeks after the cessation of drug administration. A single administration of NC-1300 to normal rats and repeated administration of NC-1300 to rats with acetic acid ulcers for four weeks after ulceration caused the same degree of inhibition of gastric acid secretion. Reduction in the area of ulceration and inhibition of gastric acid secretion by NC-1300 were significantly correlated in the indomethacin-treated animals. We conclude that NC-1300 markedly accelerates the healing of chronic gastric ulcers and prevents aggravation of the healed ulcers, presumably through antisecretory activities.     

Regenerating gene protein may mediate gastric mucosal proliferation induced by hypergastrinemia in rats

Background & Aims: Regenerating gene (Reg) has been isolated from rat regenerating pancreatic islets, and Reg protein is mitogenic to islet cells. We have recently shown that Reg gene and Reg protein are expressed in gastric enterochromaffin-like (ECL) cells. This study aimed to clarify whether gastrin enhances Reg protein production in ECL cells and whether Reg protein is mitogenic to gastric mucosal cells. Methods:Reg gene expression in response to acute and chronic hypergastrinemia was investigated in rats. Immunohistochemical studies, Northern blotting, and in situ hybridization were performed to investigate the expression of Reg protein and Reg gene. The direct effect of gastrin on Reg gene expression was investigated using isolated ECL cells, and the trophic effect of Reg protein on cultured gastric epithelial cells was assessed by [³H]thymidine uptake. Results: Both chronic hypergastrinemia and short-term gastrin administration stimulated Reg gene expression and Reg protein production in fundic mucosa. Reg gene expression was also augmented in isolated ECL cells after incubation with rat gastrin. Reg protein was mitogenic to cultured rat gastric epithelial cells. Conclusions: Gastrin stimulates the production of Reg protein in gastric ECL cells, which may be involved in the gastrin-induced gastric mucosal cell growth.GASTROENTEROLOGY 1998;115:1483-1493     

Dynamics and localization of activin A expression in rat gastric ulcers

BACKGROUND: Activin A, the homodimer of the activin/inhibin betaA subunit, has been shown to participate in cutaneous wound healing. In this study we intended to determine its part in gastric ulceration. METHODS: Activin A expression was studied by immunohistochemistry and in situ hybridization in acetic-acid-induced chronic gastric ulcers in rat. The dynamics of this process were also assessed by quantitative real time RT-PCR and RNase protection assays (RPA). The effects of different doses of this cytokine on epithelial and mesenchymal cell proliferation were quantitated in vitro. RESULTS: Low amounts of activin A and its mRNA were expressed by epithelia, endothelia and fibroblasts in intact gastric tissue. Granulation tissue of gastric ulcers and gastric glands adjacent to the ulcer rim expressed markedly increased amounts of activin protein as well as activin/inhibin betaA mRNA. RPA and RT-PCR studies revealed a more than 3-fold increase in the relative abundance of this mRNA. Activin A did not affect the proliferation rate of fibroblasts and epithelial cells in vitro. CONCLUSIONS: Activin A participates in gastric ulcer healing in a similar fashion as in cutaneous wounding. Its expression on protein and mRNA level is markedly increased in ulcer base and rim.