Changes in Gastric Mucosal Blood Flow during Healing of EMR-Induced Ulcer

Abstract: We used the laser Doppler method to study the difference in gastric mucosal blood flow changes between peptic ulcer (65 cases) and artificial ulcer caused by endoscopic mucosal resection (35 cases) during their respective healing processes. At each endoscopic ulcer stage, blood flow at the ulcer margin and that in the surrounding mucosa were measured. In the artificial ulcer, which heals easily, blood flow at the ulcer margin was still high at the scarring stage as compared with that in the corresponding area of a peptic ulcer, which is prone to relapse. Moreover, the blood flow ratio (blood flow at the ulcer margin/blood flow in the surrounding mucosa) at the S1 stage in artificial ulcers was significantly higher than that in peptic ulcers (p<0.05). These results suggest that blood flow in the SI stage is an important aspect of ulcer healing and relapse.     

Epidermal Growth Factor in Gastric Ulcer Healing by Nocloprost,a Stable Prostaglandin E2 Derivative

Background: The gastroprotective and ulcer-healing properties of prostaglandins, especially in gastric ulcers induced by non-steroidal anti-inflammatory drugs, are well established. Ulcer healing is an active process of filling the mucosal defect with migrating and proliferating epithelial cells combined with angiogenesis in granulation tissue at the ulcer bed. Growth factors, especially epidermal growth factor (EGF) and transforming growth factor alpha (TGFa) are crucial in the regulation of the reconstruction of damaged mucosal structures. Methods: In this double-blind, randomized, prospective study 40 patients with gastric ulcer were treated with nocloprost, a stable prostaglandin E₂ derivative, or with ranitidine. All subjects underwent endoscopy before and after 4 and 8 weeks of anti-ulcer therapy. During endoscopy mucosal biopsies were performed for determination of EGF content in gastric mucosa at the ulcer margin and in the intact mucosa. Additionally, EGF output in saliva and its plasma concentrations were determined in all subjects before and during the treatment. Results: The gastric ulcer healing rate after 4 weeks was significantly higher in patients treated with nocloprost than in those treated with ranitidine (63% versus 39%, respectively). At initial examination the EGF content in the gastric mucosa obtained from the ulcer edge was significantly higher than that in the intact mucosa. There was a significant increase in the EGF content in both the ulcer margin and the intact mucosa in subjects treated with nocloprost but not in patients under treatment with ranitidine. Similarly, patients treated with nocloprost had significantly higher EGF output in saliva and higher EGF concentration in plasma throughout the anti-ulcer therapy. Conclusion: Nocloprost is superior to ranitidine in the treatment of chronic gastric ulcers, and these effects could be due, at least in part, to higher expression and mucosal content of EGF in the ulcer area.     

Increased expression of epidermal growth factor receptor during gastric ulcer healing in rats.

Expression of epidermal growth factor receptor (EGFR) was studied immunohistochemically in rat gastric mucosa during healing of acetic acid-induced ulcers. In normal control gastric oxyntic mucosa, EGFR was expressed in proliferative zone cells and in some parietal cells. In mucosa of the ulcer margin, at 3, 7, and 16 days after ulcer induction, there was a 75-fold increase (over controls) in the number of cells expressing EGFR. Seventy percent of ulcers healed by the 16th day, and all were healed by the 25th day. The mucosal scar that replaced the ulcer was composed of dilated glands lined with poorly or aberrantly differentiated cells showing persistence of increased EGFR expression. An increased EGFR expression indicates an important role of EGF in ulcer healing and scar formation.     

Influence of Helicobacter pylori infection and cetraxate on gastric mucosal blood flow during healing of endoscopic mucosal resection-induced ulcers

BACKGROUND AND AIM: Helicobacter pylori (H. pylori) infection is known to affect the gastric microcirculation, and cetraxate is reported to accelerate gastric ulcer healing, possibly by augmenting gastric mucosal blood flow (MBF). The aim of this study is to clarify the effect of H. pylori infection and cetraxate on MBF during gastric ulcer healing. METHODS: Forty-two patients who had undergone endoscopic mucosal resection (EMR) were studied. Mucosal blood flow was measured by the use of a laser Doppler flowmeter in the surrounding mucosa and at the ulcer margin, before, 1 day, 1 week and 4 weeks after EMR. Helicobacter pylori infection was confirmed by the use of bacterial culture and histology. After EMR, patients were randomly assigned to receive 30 mg lansoprazole (u.i.d; L-regimen) or 30 mg lansoprazole (u.i.d.) with 200 mg cetraxate (q.i.d; LC-regimen) for 4 weeks. RESULTS: The MBF ratio (MBF at ulcer margin/MBF in surrounding mucosa) 1 week after EMR was significantly lower than that before or 4 weeks after EMR only in H. pylori-positive patients treated with the L-regimen. No such decrease in MBF was observed after 1 week in H. pylori-positive patients treated with the LC-regimen or in H. pylori-negative patients. CONCLUSION: A transient decrease in MBF was detected at the ulcer margin during healing of EMR-induced ulcers in H. pylori-infected patients. Cetraxate seemed to prevent this decrease in MBF.     

Effect of local application of growth factors on gastric ulcer healing and mucosal expression of cyclooxygenase-1 and -2

BACKGROUND/AIMS: Ulcer healing involves expression of various growth factors such as epidermal growth factor (EGF), hepatocyte growth factor (HGF) and basic fibroblast growth factor (bFGF) at the ulcer margin, but the influence of EGF, HGF and bFGF applied locally with or without neutralizing anti-EGF, HGF and bFGF antibodies or cyclooxygenase (COX)-1 and COX-2 inhibitors on ulcer healing and the expression of COX-1 and COX-2 during ulcer healing have only been studied a little. METHODS: Rats with gastric ulcers induced by serosal application of acetic acid (ulcer area 28 mm2 received a submucosal injection of either (1) vehicle (saline), (2) EGF, (3) HGF, and (4) bFGF with or without antibodies against EGF, HGF and bFGF or indomethacin (2 mg/kg/day i.p.), a nonspecific inhibitor of COX, or NS-398 (10 mg/kg/day i.g.) and Vioxx (5 mg/kg/day i.g.), both highly specific COX-2 inhibitors. A separate group of animals with chronic gastric fistulas was also used to assess gastric secretion during ulcer healing with and without growth factors. Each growth factor and specific antibody against EGF, HGF and bFGF (100 ng/100 microl each) were injected just around the ulcer immediately after ulcer induction and this local injection was repeated on day 2 following anesthesia and laparotomy. On days 13 and 21, the ulcer area was determined by planimetry, gastric blood flow (GBF) at the ulcer margin was examined by the H2-gas clearance technique, and mucosal generation of PGE2 and the gene expression of COX-1 and COX-2 in the non-ulcerated and ulcerated gastric mucosa were assessed. Gastric ulcers healed progressively within 21 days after induction and this effect was accompanied by a significant increase in GBF at the ulcer margin and in the expression of COX-2 in the ulcer area. Local treatment with EGF, HGF and bFGF produced a significant decrease in gastric acid secretion and significantly accelerated the rate of ulcer healing and raised GBF at the ulcer margin causing further significant upregulation of COX-2 but not COX-1 expression in the ulcerated mucosa. The acceleration of ulcer healing and hyperemia at the ulcer margin exhibited by locally applied EGF, HGF and bFGF were similar to those obtained with systemic administration of these growth factors. HGF applied submucosally, upregulated COX-2 expression and this was significantly attenuated by concurrent treatment with antibody against this peptide. Anti-EGF and anti-bFGF antibodies completely abolished the acceleration of the ulcer healing and hyperemia at the ulcer margin induced by these growth factors. Indomethacin and both COX-2 inhibitors significantly prolonged ulcer healing, while suppressing the generation of PGE2 in non-ulcerated and ulcerated gastric mucosa and GBF at the ulcer margin. The acceleration of ulcer healing by EGF, HGF and bFGF and the accompanying rise in GBF at the ulcer margin were significantly attenuated by the concurrent treatment with indomethacin or NS-398 and Vioxx. CONCLUSIONS: (1) Growth factors accelerate ulcer healing due to enhancement in the microcirculation around the ulcer and these effects are specific because they can be abolished by neutralization with antibodies; (2) COX-2-derived prostaglandins and suppression of gastric secretion may play an important role in the acceleration of ulcer healing by various growth factors, and (3) the local effects of EGF, HGF and bFGF on ulcer healing can be reproduced by their systemic application indicating the high efficacy of growth factors to accelerate this healing.     

Cell kinetic study on the healing process of indomethacin-induced gastric mucosal lesion of rats

In healing process of indomethacin (IND)-induced gastric mucosal lesion of rats, cell kinetics in the cells from margin of mucosal lesion, background mucosa and pyloric gland mucosa were investigated with histochemistry using bromodeoxyuridine. Results obtained were as follows; 1) In marginal cells of mucosal lesion, cell number of s-phase expressing the cell renewal abruptly increased 6 hours after IND injection, showed maximal value at 24 hours and kept higher value even at 72 hours, when the lesions were in scar stage. 2) In background mucosal cells, the cell number of s-phase showed higher value at 12 hours after IND injection, although statistically not significant, and significantly lower value at 24 and 48 hours after IND injection. 3) Some s-phase cells were observed in the surface epithelial cells covering the mucosal defect. 4) In pyloric gland mucosal cells, there was no remarkable change in cell number of s-phase during the experimental period. It was concluded that in healing process of acute gastric mucosal lesion, there was a time lag between the macroscopic observation and cell kinetics in normalization of s-phase cell number.     

Significance of Helicobacter Pylori Infection in Human Peptic Ulcers

Abstract: Experimental studies have suggested that the continuous administration of 0.02% NH, solution, induced by Helicobacter pylori (H, Pylori), leads to a glandular atrophy of the gastric mucosa, and adversely affects healing of acetic acid ulcers in rats, because of the suppression of cell kinetics of the regenerative epithelial cells and connective tissues at ulcer margins. To visualize the distribution of H. pylori in human gastric mucosa, a phenol red dye spraying endoscopy was performed in 45 patients with gastric ulcers, and 43 patients with duodenal ulcers, who were medicated with a full dose of H₂-blocker until ulcer healing, and with half doses thereafter. In the H. pylori negative cases, 8 (88.9%) of 9 gastric ulcers healed within 3 months after medication, with no relapse discernible up to 6 months after healing of the preceding ulcer. The relapse rate was 25% up to 12 months after ulcer healing. In contrast, only 22 (66.1%) of 36 gastric ulcers healed within 3 months after medication in the H. pylori positive cases. The relapse rate was 12.5% up to 3 months, 30.4% UP to 6 months and 63.6% up to 12 months after ulcer healing. In addition, all 6 duodenal ulcers healed within 2 months after medication in the H. pylori negative cases, with no relapse discernible up to 12 months after healing of the preceding ulcer. In contrast, in the H. pylon positive cases, 20 (53.1%) of 37 duodenal ulcers healed within 2 months, and the relapse rate was 14.3%, 33.3%, and 66.7% up to 3, 6 and 12 months respectively after healing of the preceding ulcer. These data suggest that H. pylori is likely to interfer with ulcer healing, and promotes peptic ulcer relapse.     

Mucosal in Vitro Permeability in the Intestinal Tract of the Pig,the Rat,and Man: Species- and Region-Related Differences

Background: Excessive upregulation of gastric epithelial cell apoptosis is speculated to be associated with ulcerogenesis in Helicobacter pylori -positive peptic ulcer disease. H. pylori may have an ulcerogenic effect through induction of gastric epithelial cell apoptosis mediated by infiltrating T cells and their soluble products. Methods: The contents of soluble Fas ligand (sFasL) and interferon- &;#110 (IFN- &;#110 ) in organ cultures and the degree of apoptosis and the expression of apoptosis-related proteins in the gastric epithelium were examined using the mucosal tissues obtained from the antrum and the ulcer site in patients with H. pylori -positive gastric ulcer (GU). The molecular mechanisms of gastric epithelial cell apoptosis induced by sFasL and IFN- &;#110 were analyzed using epithelial cell lines, MKN 45 and KATO III. Results: The mucosal tissues of the ulcer site had substantially higher contents of sFasL and IFN- &;#110 in organ cultures regardless of its healing stage in association with increased numbers of apoptotic cells and enhanced expression of proapoptotic proteins Bak and Bax in the surface foveolar epithelium as compared with the antral tissues in patients with H. pylori -positive GU. The addition of sFasL caused increases in cytotoxic cell death and caspase-3 activation in MKN 45 and KATO III cells in which IFN- &;#110 -treated cells had more prominent effects than untreated cells. The expression of Bak in MKN 45 cells increased when they were treated with IFN- &;#110. Conclusions: Upregulation of mucosal sFasL and IFN- &;#110 may be involved in ulcerogenesis in patients with H. pylori- positive GU through induction of gastric epithelial cell apoptosis.     

Upregulation of mucosal soluble fas ligand and interferon-gamma may be involved in ulcerogenesis in patients with Helicobacter pylori-positive gastric ulcer

BACKGROUND: Excessive upregulation of gastric epithelial cell apoptosis is speculated to be associated with ulcerogenesis in Helicobacter pylori-positive peptic ulcer disease. H. pylori may have an ulcerogenic effect through induction of gastric epithelial cell apoptosis mediated by infiltrating T cells and their soluble products. METHODS: The contents of soluble Fas ligand (sFasL) and interferon-gamma (IFN-gamma) in organ cultures and the degree of apoptosis and the expression of apoptosis-related proteins in the gastric epithelium were examined using the mucosal tissues obtained from the antrum and the ulcer site in patients with H. pylori-positive gastric ulcer (GU). The molecular mechanisms of gastric epithelial cell apoptosis induced by sFasL and IFN-gamma were analyzed using epithelial cell lines, MKN 45 and KATO III. RESULTS: The mucosal tissues of the ulcer site had substantially higher contents of sFasL and IFN-gamma in organ cultures regardless of its healing stage in association with increased numbers of apoptotic cells and enhanced expression of proapoptotic proteins Bak and Bax in the surface foveolar epithelium as compared with the antral tissues in patients with H. pylori-positive GU. The addition of sFasL caused increases in cytotoxic cell death and caspase-3 activation in MKN 45 and KATO III cells in which IFN-gamma treated cells had more prominent effects than untreated cells. The expression of Bak in MKN 45 cells increased when they were treated with IFN-gamma. CONCLUSIONS: Upregulation of mucosal sFasL and IFN-gamma may be involved in ulcerogenesis in patients with H. pylori-positive GU through induction of gastric epithelial cell apoptosis.     

Roles of hepatocyte growth factor and its receptor Met during gastric ulcer healing in rats

BACKGROUND & AIMS: It is unclear which growth factors are primarily responsible for stimulating gastric ulcer healing. The roles of hepatocyte growth factor (HGF) and Met/HGF receptor during gastric ulcer healing were studied in rats. METHODS: HGF and Met/HGF receptor were located and quantified by in situ hybridization and immunohistochemistry during experimental gastric ulcer healing. The in vivo effects of exogenous recombinant human HGF on cell proliferation and ulcer healing were assessed and compared with those of placebo and omeprazole treatment. RESULTS: Compared with intact oxyntic mucosa, messenger RNA (mRNA) of HGF and met was substantially greater in the ulcerated region on days 3 and 15. HGF mRNA was located in stromal cells between the regenerative glands and in the arterial vessels of submucosal tissue, whereas met mRNA was located in the epithelial cells of the regenerative glands. After cryoinjury, immunoreactivity for the Met/HGF receptor was absent on day 3, reappeared on day 8, and was overexpressed on day 15. Exogenous recombinant human HGF had no effect on the ulcer healing parameters over days 3-8, but it did increase epithelial cell proliferation in the ulcer margin over days 8-15. CONCLUSIONS: These data suggest that HGF mediates specific tissue interactions between mesenchyme and epithelia during gastric ulcer healing. (Gastroenterology 1997 Dec;113(6):1858-72)     

Cyclooxygenase 2-implications on maintenance of gastric mucosal integrity and ulcer healing: controversial issues and perspectives

Cyclooxygenase (COX), the key enzyme for synthesis of prostaglandins, exists in two isoforms (COX-1 and COX-2). COX-1 is constitutively expressed in the gastrointestinal tract in large quantities and has been suggested to maintain mucosal integrity through continuous generation of prostaglandins. COX-2 is induced predominantly during inflammation. On this premise selective COX-2 inhibitors not affecting COX-1 in the gastrointestinal tract mucosa have been developed as gastrointestinal sparing anti-inflammatory drugs. They appear to be well tolerated by experimental animals and humans following acute and chronic (three or more months) administration. However, there is increasing evidence that COX-2 has a greater physiological role than merely mediating pain and inflammation. Thus gastric and intestinal lesions do not develop when COX-1 is inhibited but only when the activity of both COX-1 and COX-2 is suppressed. Selective COX-2 inhibitors delay the healing of experimental gastric ulcers to the same extent as non-COX-2 specific non-steroidal anti-inflammatory drugs (NSAIDs). Moreover, when given chronically to experimental animals, they can activate experimental colitis and cause intestinal perforation. The direct involvement of COX-2 in ulcer healing has been supported by observations that expression of COX-2 mRNA and protein is upregulated at the ulcer margin in a temporal and spatial relation to enhanced epithelial cell proliferation and increased expression of growth factors. Moreover, there is increasing evidence that upregulation of COX-2 mRNA and protein occurs during exposure of the gastric mucosa to noxious agents or to ischaemia-reperfusion. These observations support the concept that COX-2 represents (in addition to COX-1) a further line of defence for the gastrointestinal mucosa necessary for maintenance of mucosal integrity and ulcer healing.     

Candida overgrowth in gastric juice of peptic ulcer subjects on short- and long-term treatment with H2-receptor antagonists

Candida overgrowth in gastric juice of peptic ulcer subjects under therapy with H2-receptor (H2-R) antagonists has been detected in 21.4 and 53.8% of cases after short- and long-term treatment respectively, and in 8% of controls. Both types of H2-R antagonists, ranitidine and cimetidine, were equally associated with production of yeasts. The location of ulcers, whether gastric or duodenal, seems to have no influence on fungal growth. Females were more susceptible than males to develop Candida in gastric juice. In the short-term course with H2-R blockers fungal colonization of gastric juice was associated with delay of the rate of ulcer healing. Fungal detection in gastric juice was not associated with mucosal invasion by Candida since in none of the patients who had a biopsy for gastric ulcer was Candida detected by histology.     

Basic fibroblast growth factor accelerates gastric mucosal restoration in vitro by promoting mesenchymal cell migration and proliferation

It has been generally accepted that basic fibroblast growth factor is a potent stimulator of duodenal ulcer healing. However, the detailed mechanism and mode of action of growth factor on gastric ulcer healing is still controversial. Therefore, in the present study, the effects of basic fibroblast growth factor on gastric mucosal repair were studied using an in vitro cultured cell system. Artificial wounds were made in confluent monolayer rabbit gastric fibroblast and epithelial cell sheets by mechanical denudation. Changes in the size of the cell-free area were analysed quantitatively. Cell proliferation was assessed by BrdU staining. For both cell types, mucosal restoration involved cell migration and proliferation. Although the speed of restoration of epithelial cells was not affected by the addition of basic fibroblast growth factor, it was much faster for epithelial cells than for fibroblasts. Basic fibroblast growth factor accelerated wound repair of fibroblasts but not epithelial cells. Basic fibroblast growth factor accelerated wound repair by stimulating both cell migration and proliferation. Therefore, the effects of basic fibroblast growth factor in peptic ulcer diseases may be mainly due to the stimulation of mesenchymal cells.     

Expression of functional neurokinin-1 receptors in regenerative glands during gastric wound healing in rodents

BACKGROUND & AIMS: Although functions of the neurokinin-1 receptor have been well explored in neurogenic inflammation and immunoinflammatory responses, little is known about neurokinin-1 receptors during gastric wound healing. The aim of this study was to assess whether neurokinin-1 receptors play a role in gastric wound healing. METHODS: In vitro neurokinin-1 receptor autoradiography and immunohistochemistry were performed to identify, locate, and quantify neurokinin-1 receptors during wound healing in rodents with cryoulcers in the gastric corpus and antrum. Moreover, to assess the functionality of these receptors, the effect of the neurokinin-1 receptor antagonist NKP608 on gastric wound healing was quantified in vivo in wild-type and cyclooxygenase-2(-/-) mice. RESULTS: Regenerative glands of the mucosal ulcer margin of rat cryoulcers of the gastric corpus showed strong expression of neurokinin-1 receptors in binding studies between days 3 and 22, with little expression on days 29-84. In addition, strong immunoreactivity for neurokinin-1 receptors was detected on the cell membrane of these regenerative glands. Expression of neurokinin-1 receptors in regenerative glands was confirmed in the rat antrum and the mouse gastric corpus. Moreover, in vivo functional tests during gastric ulcer healing showed that cell proliferation in the regenerative epithelia of the ulcer margin was significantly decreased by NKP608 compared with placebo; furthermore, gastric ulcer healing was significantly delayed by NKP608 both in wild-type and cyclooxygenase-2(-/-) mice. CONCLUSIONS: This report shows the time-limited overexpression of neurokinin-1 receptors in the mucosal repair tissue of the corpus and antrum. Our in vitro and in vivo data suggest that neurokinin-1 receptors are involved in gastric wound healing.     

三叶因子2表达与胃溃疡易感性的相关研究

目的　三叶因子 (trefoilfactor)是一组新发现的对胃肠道有保护作用的多肽类物质 ,通过对三叶因子 2 (TFF2 )mRNA在胃溃疡与浅表性胃炎患者胃黏膜中表达水平的差异研究 ,探讨其在胃溃疡发病机制中的作用。方法　胃镜下钳取 32例胃溃疡内侧缘、溃疡远处和 36例浅表性胃炎患者的组织标本 ,利用原位杂交方法分别对不同组织中TFF2mRNA进行定位和半定量测定 ,比较TFF2mRNA在各组中的表达差异。结果　TFF2mRNA主要分布于胃小凹基底部的柱状细胞、幽门腺腺泡及导管细胞中。TFF2mRNA在浅表性胃炎组的表达高于胃溃疡内侧缘组 ,在胃溃疡内侧缘表达要高于溃疡 5cm外的胃黏膜 ,但组间表达差异无显著性 (P均 >0 .0 5 ) ,而浅表性胃炎标本TFF2mRNA阳性程度显著高于溃疡外 5cm组 (P <0 .0 5 )。结论　TFF2mRNA在胃黏膜中广泛分布 ,胃溃疡患者胃黏膜中TFF2mRNA的低表达可能是胃溃疡易患因素之一。     

Reduction in index of oxygen saturation at margin of active duodenal ulcers may lead to slow healing

This study tested the hypothesis that reduced perfusion of a duodenal ulcer margin (ie, the mucosa 1–2 mm from the edge of the ulcer base) is associated with slow healing. Reflectance spectrophotometric measurement of indices of mucosal hemoglobin concentration (IHB) and mucosal hemoglobin oxygen saturation (ISO₂) were obtained endoscopically in 21 patients at the ulcer margin and the adjacent mucosa (ie, the mucosa 1–2 cm from the edge of the ulcer base). In 17 patients with adequate follow-up, stepwise multilinear regression analysis revealed a significantly negative correlation (r=s-0.69, P < 0.05) between ISO₂ at the ulcer margin minus ISO₂ at the adjacent mucosa (ISO)₂ and ulcer healing time. In addition, smoking, being black, and early relapse since the last ulcer attack were found to be associated with increased duration required for healing. The results of this pilot study suggest factors, in addition to smoking, that may have to be considered in future studies concerned with duodenal ulcer healing.This work was supported by the National Institute of Arthritis and Metabolism and Digestive Diseases Grant AM34840, American Society for Gastrointestinal Endoscopy Career Development Award H850208, Veterans Administration Medical Research Funds, and UCLA Academic Senate Grant 4063.     

Omentum and basic fibroblast growth factor in healing of chronic gastric ulcerations in rats

Omentum was shown to exhibit angiogenic activity, but its role in healing of chronic gastric ulcers is unknown. This study was designed to compare the effects of omentum and basic fibroblast growth factor (bFGF), a potent angiogenic factor, on healing of chronic gastric ulcers in rats. Several series of rats with gastric ulcers were used: series A with intact omentum (control), series B with omentum resected, and series C with omentum placed on the serosal side of the ulcer. Series A–C were divided into four groups treated with vehicle (I); indomethacin (II), an inhibitor of prostaglandin formation, difluoromethylornithine (DFMO) (III); an inhibitor of polyamine biosynthesis or bFGF (IV). Seven days after ulcer induction, the animals were anesthetized, the gastric blood flow (GBF) was determined by laser Doppler flowmetry (LDF), and the ulcer area was measured by planimetry. Biopsy samples of the ulcer margin were taken for determination of the number of capillaries and myofibroblasts in the granulation tissue. Attachment of omentum significantly accelerated ulcer healing, whereas omentectomy delayed this process. LDF revealed the decrease in the GBF at the ulcer margin to 45% and at the ulcer bed to 18% of the value recorded in the intact adjacent mucosa. Attachment of the omentum significantly increased the blood flow at the ulcer margin and increased the number of capillaries and myofibroblasts in the granulation tissue. Indomethacin (1 mg/kg/day) that inhibited mucosal PGE₂ by about 85% delayed significantly ulcer healing without affecting the blood flow in the ulcer area. DFMO (200 mg/kg intraperitoneally) suppressed ODC activity in the mucosa but did not influence the ulcer healing. bFGF given subcutaneously accelerated dose-dependently ulcer healing and stimulated angiogenesis to a similar extent as the attached omentum. We conclude that omentum enhances the ulcer healing in similar way as bFGF and that this effect is accompanied by the increased angiogenesis and blood flow in the ulcer area.     

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.     

Distribution of Collagen Types I,III, and IV in Peptic Ulcer and Normal Gastric Mucosa in Man

The quality of peptic ulcer healing does not only mean complete epithelial restitution of the mucosal surface but also adequate repair of the underlying connective tissue. To obtain more information about the metabolism of extracellular matrix proteins in gastric mucosa and submucosa, we investigated biopsy specimens from six patients with antral peptic ulcers and six normal controls by staining of collagen types I, III, and IV with an immunofluorescence technique. In normal mucosa we found a certain amount of collagen types I and III in equal distribution and almost no collagen type IV. In contrast, there was a remarkable increase of collagen types I and III in peptic ulcers predominantly located at the ulcer edges. These results are compatible with the view that extracellular matrix proteins play some part in the ulcer healing process.