Gastric ulcer healing and basic fibroblast growth factor: effects of lansoprazole and famotidine

Mucosal concentration of basic fibroblast growth factor in the healing process in human giant gastric ulcers

OBJECTIVES

Basic fibroblast growth factor (bFGF) is a key factor in the healing of human and experimental peptic ulcers, but the behavior of bFGF in human giant gastric ulcer remains to be determined. We determined the bFGF content in the rim of giant ulcers (bFGF rim) and in non-ulcerated mucosa located opposite the ulcer (bFGF opposite) before and during treatment.

METHODS

Biopsy specimens were endoscopically obtained from 31 patients with giant gastric ulcers and 17 patients with small ulcers before and 2, 4 and 8 weeks after treatment. The bFGF concentrations in the specimens were measured using a sandwich enzyme immunoassay.

RESULTS

Before treatment, the bFGF rim and bFGF opposite concentrations were not associated with ulcer size. The bFGF rim concentration before treatment in the rapid healing group was higher than that in the slow healing group, but no significant difference in bFGF opposite concentrations were found between the two groups. The bFGF rim concentration in the rapid healing patients decreased during treatment, while the slow healing patients showed an inverse response. The bFGF opposite concentration did not change during treatment and bFGF rim concentrations in Helicobacter pylori-positive stomachs were significantly lower than those in H. pylori-negative stomachs.

CONCLUSIONS

The bFGF rim concentration is not involved in the formation of giant gastric ulcers in humans. However, the bFGF rim concentration does appear to promote healing. The bFGF opposite concentration is not related to either the formation or healing of giant gastric ulcers.

Effect of exogenous administration of transforming growth factor-beta and famotidine on the healing of duodenal ulcer under the impact of indomethacin

BACKGROUND

Non-steroidal anti-inflammatory drugs delay ulcer healing and cause refractory peptic ulcers in humans.

OBJECTIVE

To study the effects of growth factors on experimental duodenal ulcer healing in indomethacin-treated rats.

METHODS

Duodenal ulcers were induced in male Wistar rats by the serosal application of 75% acetic acid for 10 s. Rats were then treated with indomethacin (2 mg/kg/day; s.c.), transforming growth factor beta (15 ng locally injected subserosally at the ulcer site) or famotidine (5 mg/kg/day; p.o.), vehicle or combinations of treatments. On day 5, 8 or 12, rats were sacrificed and the ulcer area planimetrically measured under a dissecting microscope. Macroscopic area, microscopic diameter, collagen content and mucosal regeneration were assessed in histological preparations. Gastric secretion was assessed also in the pylorus-ligated rat-model. Data expressed as median and ranges were analyzed by non-parametric test.

RESULTS

Indomethacin delayed ulcer healing but transforming growth factor-beta and famotidine improved ulcer healing and reversed the effects of indomethacin. Maximal differences were observed on day 8. Transforming growth factor-beta was associated with an increase in epithelial and granulation tissue cell proliferation. Famotidine induced a profound inhibition of gastric secretion and increased collagen secretion but it did not affect cell proliferation.

CONCLUSIONS

Transforming growth factor-beta and famotidine accelerate ulcer healing delayed by indomethacin.

Effects of omeprazole and famotidine on fibroblast growth factor-2 during artificial gastric ulcer healing in humans

BACKGROUND AND AIMS

Endoscopic mucosal resection is a widely accepted technique for the treatment of early gastric cancers, while large ulcers induced by the treatment should be treated promptly. This study aimed to compare the effects of omeprazole and famotidine on ulcer healing and fibroblast growth factor-2 levels in gastric ulcers induced by endoscopic mucosal resection.

METHODS

Sixteen patients indicated for endoscopic mucosal resection were enrolled. They were treated by using either omeprazole (n = 8) or famotidine (n = 8) after endoscopic mucosal resection. Endoscopy was performed on days 4, 7 and 28 during each treatment period. Levels of fibroblast growth factor-2 in biopsy specimens were measured by using an enzyme-linked immunosorbent assay at the time of and after endoscopic mucosal resection. Histological variables were also assessed.

RESULTS

Ulcer healing rates under endoscopy were not different between the two treatment groups. In both groups, levels of fibroblast growth factor-2 slightly increased on day 4, but the values were not different at any time point. There were no differences in histological variables on days 4 and 7, but fibromuscular hyperplasia was significantly greater in the omeprazole group than in the famotidine group on day 28 (P < 0.05).

CONCLUSIONS

Omeprazole and famotidine have an equivalent value for the treatment of ulcers induced by endoscopic mucosal resection. While omeprazole had a more potent effect on fibromuscular hyperplasia than did famotidine, such a difference does not seem to be explained by fibroblast growth factor-2.

Role of growth factors and their receptors in gastric ulcer healing

The repair of gastric ulcers requires the reconstitution of epithelial structures and the underlying connective tissue, including vessels and muscle layers. Several growth factors have been implicated in this process, since they are able to regulate important cell functions, such as cell proliferation, migration, differentiation, secretion, and degradation of extracellular matrix, all of which are essential during tissue healing. Epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), hepatocyte growth factor (HGF), and trefoil factors (TFFs) are mainly involved in the reconstitution of the epithelial structures. Platelet derived growth factor (PDGF), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and transforming growth factor-beta (TGF-beta) play a major role in the reconstitution of connective tissue, including vessels and smooth muscle cells, and provide the extracellular matrix substrate for cell migration and differentiation. The expression of these growth factors and their receptors is increased during ulcer healing and, in some cases, intracellular signaling related to receptor binding and transduction has been demonstrated. EGF, TGF-alpha and TFFs are normally present either in the gastric juice or in the mucosa, and may exert their effects immediately after damage, before newly synthesized EGF and TFFs are released from the ulcer margin. The inhibition of their effects by neutralizing antibodies may result in delayed ulcer healing, while the administration of recombinant or natural analogues may improve ulcer repair. In this review, we will summarize the basic molecular characteristics of some of these growth factors, and will discuss available evidence supporting their role in the ulcer repair process.

Effect of basic fibroblast growth factor on gastric ulcer healing and its own mRNA expression

BACKGROUND

The application of an acid-stable mutein of basic fibroblast growth factor (bFGF) called CS23 results in acceleration of ulcer healing. The modes by which this cytokine exerts these effects are not yet completely understood.

AIM

To describe the pattern of bFGF-mRNA expression during ulcer healing and to examine the effects of exogenously applied CS23 on gastric ulcer healing in an animal model.

METHODS

The speed of healing of gastric ulcers, expression of extracellular matrix gene mRNAs such as pro alpha(I) collagen (by non-radioactive in situ hybridization), cellular proliferation evidenced by the display of PCNA (by immunohistochemistry), angiogenesis, and the feedback of this growth factor on its own mRNA expression pattern were used to evaluate the effects of CS23 on rat gastric ulcer healing in an animal model.

RESULTS

CS23 accelerates gastric ulcer healing at 7, 14 and 21 days after ulcer induction. We found an increase in connective tissue beneath the ulcer bed in treated animals in comparison to controls. The expression of PCNA as well as pro alpha(I) collagen mRNA was markedly increased in ulcers, yet there was no distinct difference between treatment arms. In contrast, the density of microvessels was significantly increased in the submucosa of ulcers by CS23 application. bFGF-mRNA expression is up-regulated in the submucosa during early ulcer healing; this increase diminishes within days but can be restituted by the exogenous application of CS23.

CONCLUSIONS

CS23 speeds gastric ulcer healing and significantly increases the density of microvessels in the ulcerated tissue without affecting the numbers of proliferating cells or the transcription of collagen mRNA. In addition, it augments the expression of bFGF-mRNA during the later stages of healing, suggesting a positive feedback loop.

Expression of the cyclooxygenase-2 gene in gastric epithelium

This study examined the mRNA level of cyclooxygenase-2 (cox-2) in a rat gastric mucosal cell line after growth stimulation in vitro and in rat gastric mucosa before and after acid-induced injury in vivo. RGMI cells were stimulated with fetal calf serum in the in vitro study. Thereafter, the cox-2 mRNA level was examined by Northern analysis. Effects of NS-398, a specific inhibitor of cox-2, and indomethacin on prostaglandin production and cell proliferation were examined in RGM1 cells. In the in vivo study, rats were given 1 ml of 0.6 N hydrochloric acid into the stomach. The level of cox-2 mRNA was examined in rat gastric mucosa after acid administration. Cox-2 mRNA increased 20-60 min after growth stimulation in RGM1 cells. Both NS-398 and indomethacin suppressed prostaglandin production and cell proliferation after growth stimulation. Expression of cox-2 mRNA was observed 40 and 60 min after administration of 0.6 N HCl. Gastric lesions developed within 60 min after HCl administration and healed significantly within 48 h. The present study shows the expression of cox-2 in gastric epithelial cells in vitro and in gastric mucosa after injury in vivo. The results also suggest that cox-2 is involved in de novo synthesis of prostaglandins and cell proliferation in gastric epithelium.

Lansoprazole compared with histamine2-receptor antagonists in healing gastric ulcers: a meta-analysis

To compare the gastric ulcer healing rates of lansoprazole with histamine2-receptor antagonists (H2RAs) (ranitidine, famotidine, cimetidine, and roxatidine), a meta-analysis was performed using data from five published and eight unpublished randomized controlled trials. Analyses were performed using (1) both evaluable patients (n = 1527) and all randomized patients (n = 1655) (assuming that patients lost to follow-up were treatment failures); (2) all studies and a subset of studies that received high methodologic quality scores; and (3) fixed-effects, random-effects, and Bayesian statistical models. In all cases, lansoprazole was associated with a significantly higher rate of endoscopic healing at both 4 and 8 weeks compared with the H2RAs. When the most conservative Bayesian statistical model and intent-to-treat analysis were used, lansoprazole was associated with a 33% higher healing rate at 4 weeks (risk ratio = 1.33; 95% confidence interval [CI] = 1.19 to 1.49) and a 12% higher healing rate at 8 weeks (risk ratio = 1.12; 95% CI = 1.06 to 1.19) than were the H2RA agents. Similar results were obtained when the meta-analysis was performed on evaluable rather than all randomized patients and using the three different analytical techniques noted above. Slightly lower, though still highly significant, improvement in ulcer healing rates was obtained when the meta-analysis was performed using a subset of six studies that received high methodologic quality scores. These results support the conclusion that lansoprazole heals ulcers more quickly than do the H2RAs and also achieves higher overall rates of healing. The eradication of Helicobacter pylori associated with gastric ulcers was not assessed in individual studies.