Basic fibroblast growth factor treatment for non-steroidal anti-inflammatory drug associated gastric ulceration

Angiogenesis and its therapeutic opportunities

Angiogenesis plays critical roles in human physiology that range from reproduction and fetal growth to wound healing and tissue repair. The sophisticated multistep process is tightly regulated in a spatial and temporal manner by "on-off switch signals" between angiogenic factors, extracellular matrix components, and endothelial cells. Uncontrolled angiogenesis may lead to several angiogenic disorders, including vascular insufficiency (myocardial or critical limb ischemia) and vascular overgrowth (hemangiomas, vascularized tumors, and retinopathies). Thus, numerous therapeutic opportunities can be envisaged through the successful understanding and subsequent manipulation of angiogenesis. Here, we review the clinical implications of angiogenesis and discuss pro- and antiangiogenic agents that offer potential therapy for cancer and other angiogenic diseases.

Mast cells are critical for protection against peptic ulcers induced by the NSAID piroxicam

Many commonly used non-steroidal anti-inflammatory drugs (NSAIDs) also cause gastrointestinal toxicity, including the development of life-threatening peptic ulcers. We report that mast cell-deficient mice have an extremely high incidence of severe peptic ulceration when exposed to the NSAID piroxicam. This enhanced ulcer susceptibility can be reversed by reconstitution with mast cells. Furthermore, wild type mice treated with diphenhydramine hydrochloride, a commonly used antihistamine that blocks histamine H1 receptors, develop a similarly high incidence of peptic ulcers following piroxicam exposure. The protective effect of mast cells is independent of TNF, blockade of H2 receptors, or acid secretion. These data indicate a critical role for mast cells and the histamine that they produce in prevention and/or repair of piroxicam-induced gastric mucosal injury. Additional studies will be required to determine whether this represents a NSAID class effect that can be exploited to develop novel therapeutic strategies to limit the incidence of NSAID-induced side effects in humans.

Alleviation of experimental ulcerative colitis with the synthetic peptide, F2A4-K-NS (Fibratide)

Recombinant fibroblast growth factors (FGFs) maintain the integrity of the gut epithelium and reduce mucosal injury in experimental inflammatory bowel disease (IBD). Chemically synthesized FGF mimetics could potentially extend the utility of FGFs by tailoring them for optimal bioactivity and oral administration, for example. Here, F2A4-K-NS (Fibratide), a synthetic FGF mimetic peptide, alleviated dextran sulfate sodium (DSS)-induced ulcerative colitis in mice when delivered systemically and, to a lesser extent, orally. Intraperitoneal injection of Fibratide (1 or 5 mg/kg/day) ameliorated DSS-induced ulcerative colitis, resulting in reduced weight loss, decreased colon wall thickening, and increased colon length. Fibratide also improved epithelial integrity by reducing histological-detectable crypt damage and inflammation. Orally administered Fibratide (1 mg/kg/day) was also effective in ameliorating symptoms with effects generally similar to those of intraperitoneal injection. In vitro studies were conducted to help clarify how Fibratide might act in vivo. Fibratide exhibited a modest enhancement of epithelial cell proliferation. On the other hand, Fibratide doubled the rate of epithelial cells migration and restitution in a cell culture model of wound repair. Collectively, the results indicate that Fibratide reduced the severity of experimental ulcerative colitis and may be potentially useful in the treatment of IBD.

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.

The healing effects of Centella extract and asiaticoside on acetic acid induced gastric ulcers in rats

In this study, the healing effects of Centella asiatica water extract (CE) and asiaticoside (AC), an active constituent of CE, on acetic acid induced gastric ulcers (kissing ulcers) in rats were examined. CE was prepared from Centella asiatica dry plant and the concentration of AC in CE was quantitatively determined with the use of high performance liquid chromatography analysis. Different concentrations of CE and AC were orally administered to rats with kissing ulcers. They were found to reduce the size of the ulcers at day 3 and 7 in a dose-dependent manner, with a concomitant attenuation of myeloperoxidase activity at the ulcer tissues. Epithelial cell proliferation and angiogenesis were on the other hand promoted. The expression of basic fibroblast growth factor, an important angiogenic factor, was also upregulated in the ulcer tissues in rats treated with CE or AC. These results further suggest the potential use of Centella asiatica and its active ingredient as anti-gastric ulcers drugs.

Antiangiogenic effect of a highly selective cyclooxygenase-2 inhibitor on gastric ulcer healing in rats

Selective cyclooxygenase-2 (COX-2) inhibitors have been shown to produce fewer gastrointestinal adverse reactions when compared with conventional nonselective nonsteroidal anti-inflammatory drugs and they suppress angiogenesis in tumors. The purpose of the present study was to investigate the effects of highly selective COX-2 inhibitor on angiogenesis and protein expression of angiogenic factor during gastric ulcer healing. Gastric ulcers were induced in male Sprague-Dawley rats by a luminal application of acetic acid solution. Rofecoxib, a selective COX-2 inhibitor, was administered at a dose of 10 mg/kg/day by gastric intubation for 14 successive days. The ulcer size was measured at different time intervals after ulcer induction. The microvessels that were immunohistologically positive for von Willebrand factor within the ulcer bed were counted. The protein levels of basic fibroblast growth factor (bFGF) and concentration of prostaglandin E(2) (PGE(2)) in the ulcer tissues were analyzed with Western blotting and immunoassay methods, respectively. The results demonstrated that rofecoxib treatment significantly increased the ulcer size at days 6, 10, and 15. It decreased the number of microvessels, bFGF protein expression, and PGE(2) level in the ulcer base at day 6. The findings that highly selective COX-2 inhibitor delayed ulcer healing in rats and impaired angiogenesis in the ulcer base raise cautions regarding the use of COX-2 inhibitors in patients with gastric ulcers.

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.

Immunohistochemical detection of fibroblast growth factor receptors in normal endocrine cells and related tumors of the digestive system

Endocrine tumors (ETs) of the digestive system produce several growth factors including acidic and basic fibroblast growth factors (aFGF and bFGF, respectively), which are thought to be involved in the growth of tumor cells and in the proliferation of tumor stromal cells. Their actions depend on binding to four specific receptors--FGFR1, FGFR2, FGFR3, and FGFR4--whose distribution in normal endocrine cells and related tumors of the gastroenteropancreatic (GEP) system has previously been examined. Formalin-fixed, paraffin-embedded normal tissues and 60 well-characterized GEP endocrine tumors were immunostained using specific antibodies directed against various GEP hormones, aFGF, FGFR1, FGFR2, FGFR3, and FGFR4. Acidic FGF immunoreactivity (IR) was found in gut EC cells; FGFR1 immunoreactivity in rare duodenal endocrine cells and in pancreatic A cells; FGFR2 immunoreactivity in gastric and duodenal G cells, pancreatic B cells, and rectal EC cells; FGFR3 immunoreactivity in duodenal G cells; and FGFR4 immunoreactivity in rectal L cells and in pancreatic B, PP, and A cells. Immunoreactivity for at least one of the four FGFRs was found in all tumors, independently of FGFR expression in the putative cell of origin. EC cell tumors, which were all positive for aFGF, were found to express at least three different FGFRs. FGFRs also were localized in the stromal cells of all the tumors examined. The tumor stroma was more abundant in EC cell tumors than in other types of neoplasms. The results suggest that aFGF-FGFR interaction may be involved in the modulation of normal endocrine cell functions and in the regulation of tumor growth and stromal proliferation of EC cell carcinoids.

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.

Myofibroblasts. II. Intestinal subepithelial myofibroblasts

Intestinal subepithelial myofibroblasts (ISEMF) and the interstitial cells of Cajal are the two types of myofibroblasts identified in the intestine. Intestinal myofibroblasts are activated and proliferate in response to various growth factors, particularly the platelet-derived growth factor (PDGF) family, which includes PDGF-BB and stem cell factor (SCF), through expression of PDGF receptors and the SCF receptor c-kit. ISEMF have been shown to play important roles in the organogenesis of the intestine, and growth factors and cytokines secreted by these cells promote epithelial restitution and proliferation, i.e., wound repair. Their role in the fibrosis of Crohn's disease and collagenous colitis is being investigated. Through cyclooxygenase (COX)-1 and COX-2 activation, ISEMF augment intestinal ion secretion in response to certain secretagogues. By forming a subepithelial barrier to Na(+) diffusion, they create a hypertonic compartment that may account for the ability of the gut to transport fluid against an adverse osmotic gradient. Through the paracrine secretion of prostaglandins and growth factors (e.g., transforming growth factor-beta), ISEMF may play a role in colonic tumorigenesis and metastasis. COX-2 in polyp ISEMF may be a target for nonsteroidal anti-inflammatory drugs (NSAIDs), which would account for the regression of the neoplasms in familial adenomatous polyposis and the preventive effect of NSAIDs in the development of sporadic colon neoplasms. More investigation is needed to clarify the functions of these pleiotropic cells.

Myofibroblasts. I. Paracrine cells important in health and disease

Myofibroblasts are a unique group of smooth-muscle-like fibroblasts that have a similar appearance and function regardless of their tissue of residence. Through the secretion of inflammatory and anti-inflammatory cytokines, chemokines, growth factors, both lipid and gaseous inflammatory mediators, as well as extracellular matrix proteins and proteases, they play an important role in organogenesis and oncogenesis, inflammation, repair, and fibrosis in most organs and tissues. Platelet-derived growth factor (PDGF) and stem cell factor are two secreted proteins responsible for differentiating myofibroblasts from embryological stem cells. These and other growth factors cause proliferation of myofibroblasts, and myofibroblast secretion of extracellular matrix (ECM) molecules and various cytokines and growth factors causes mobility, proliferation, and differentiation of epithelial or parenchymal cells. Repeated cycles of injury and repair lead to organ or tissue fibrosis through secretion of ECM by the myofibroblasts. Transforming growth factor-beta and the PDGF family of growth factors are the key factors in the fibrotic response. Because of their ubiquitous presence in all tissues, myofibroblasts play important roles in various organ diseases and perhaps in multisystem diseases as well.

Effect of chronic duodenal ulceration and its treatment with lanzoprazole or sucralfate on gastroduodenal mucosal protein turnover and TGF-alpha, bFGF, and EGF receptor expression in humans

In order to investigate whether chronic duodenal ulcer disease is a consequence of disturbed mucosal turnover and growth factor expression, we studied 16 patients with duodenal ulcers before, during, and after endoscopic healing with lansoprazole or sucralfate. Before treatment, gastric fundal and antral mucosal protein turnover rates were higher in patients than controls, without parallel increases in growth factors. Both forms of therapy produced similar changes, with overall increases in duodenal mucosal turnover and transforming growth factor-alpha (TGF-alpha) and epidermal growth factor receptor (EGF-r) levels. Measurements after healing showed persistent elevations of mucosal turnover in the antrum and duodenum and depressions of basic fibroblast growth factor (bFGF) in gastric fundal and duodenal mucosa. We conclude that mucosal turnover is abnormally high in patients with chronic duodenal ulcer disease and is not easily explained by growth factor changes. The failure of lansoprazole and sucralfate to normalize rates, despite endoscopic healing, may explain the high ulcer relapse rates in non-HP-eradicated patients.

Expression of basic fibroblast growth factor in intact and ulcerated human gastric mucosa

BACKGROUND

Basic fibroblast growth factor (bFGF) promotes angiogenesis and healing of gastric ulcers in rats, and bFGF expression is up regulated in such ulcers. However, little is known about expression of bFGF in human gastric mucosa.

AIMS

To investigate bFGF expression in intact human gastric mucosa and gastric ulcers and to determine whether low bFGF content or altered binding by mucosa is associated with ulceration.

SUBJECTS

Endoscopy outpatients, gastrectomy patients, and organ donors.

METHODS

bFGF was isolated by heparin affinity chromatography and characterised by western blotting and endothelial cell bioassay. bFGF was measured by immunoassay and its distribution defined by immunohistochemistry and in situ hybridisation. Binding of bFGF by heparan sulphate proteoglycans was investigated by sodium chloride and heparin extraction.

RESULTS

Bioactive bFGF (19 kDa) was detected in normal mucosa but bFGF mRNA was not found. bFGF expression was up regulated in granulation tissue endothelial cells, mononuclear cells, and epithelial cells at the ulcer rim. Gastric ulcer patients had constitutively low bFGF concentrations in intact antral mucosa which were not explained by changes in binding to heparan sulphate proteoglycans.

CONCLUSIONS

bFGF expression is up regulated in human gastric ulcers. Low intact mucosal bFGF content is associated with gastric ulceration.

Prevention of gastric ulcer relapse induced by indomethacin in rats by a mutein of basic fibroblast growth factor

We found indomethacin aggravates healed gastric ulcers (ulcer relapse) in rats. In the present study, we examined the effects of human basic fibroblast growth factor (bFGF) mutein CS23 (TGP-580) and histamine H2-receptor antagonists (H2-RAs) on ulcer relapse in this model. In male SD rats, gastric ulcers were induced in the antrum by injection of acetic acid. Indomethacin (1 mg/kg/day) given s.c. for 2 weeks starting 4 weeks after the operation aggravated the healed ulcer; the areas with and without indomethacin were 4.8 +/- 1.4 and 0.4 +/- 0.3 mm2, respectively. Drugs were given orally once daily for 4 weeks starting 2 days after the operation or for the 2-week indomethacin administration period. Treatment with ranitidine (100 mg/kg), cimetidine (100 mg/kg) and TGP-580 (0.1 mg/kg) for 4 weeks accelerated the healing. The aggravation by indomethacin was significantly inhibited by pretreatment with TGP-580 and mildly inhibited by cimetidine but not ranitidine. When the drugs were co-administered with indomethacin for 2 weeks, the aggravation was significantly prevented by ranitidine and mildly inhibited by cimetidine and TGP-580. Both TGP-580 and H2-RAs can prevent the ulcer relapse induced by indomethacin but via different modes of action: TGP-580 inhibits relapse mainly by acting on the process of healing, while H2-RAs act mainly on the process of aggravation.

Healing with basic fibroblast growth factor is associated with reduced indomethacin induced relapse in a human model of gastric ulceration

BACKGROUND

Acid stable basic fibroblast growth factor (bFGF) promotes angiogenesis and healing of gastric ulcers in rats and reduces subsequent non-steroidal anti-inflammatory drug (NSAID) induced relapse.

AIMS

To test in a double blind, placebo controlled, three way crossover study whether bFGF promotes healing and reduces subsequent relapse in a human model of gastric ulceration.

SUBJECTS

Twelve healthy volunteers.

METHODS

Subjects took aspirin 900 mg twice daily (days 1-3) with bFGF 0.1 mg twice daily or cimetidine 400 mg twice daily or placebo (days 1-14) and then indomethacin 50 mg thrice daily (days 15-21). Endoscopy was performed on days 1, 4, 8, 15, and 22 during each treatment period. Eight antral biopsy specimens were taken on day 1 and the number of unhealed biopsy induced mini-ulcers and NSAID induced erosions counted during subsequent endoscopies.

RESULTS

Basic FGF and cimetidine were protective against aspirin and indomethacin induced duodenal (but not gastric) injury compared with placebo. There was significant relapse of biopsy induced mini-ulcers after indomethacin only in the placebo group (0 (0-0) before v 1 (0-4.5) after; p > 0.05). TGP-580 was detected in serum of one volunteer.

CONCLUSIONS

Healing with bFGF (and cimetidine) was associated with reduced NSAID induced ulcer relapse in this model of gastric ulceration.

Growth factors in angiogenesis: current interest and therapeutic potential

Angiogenesis, the process of new blood vessel development, is an essential component of the body's physiology and contributes to the pathogenesis of a variety of diseases such as benign and malignant neoplasia and rheumatoid arthritis. Failure of this physiological response is also important in abnormalities of wound healing in diseases such as duodenal ulceration and diabetes. Angiogenesis is controlled by a variety of factors that initiate, control and terminate this complex, multi-stage process. This review covers those factors that are exciting much interest currently and have potential for incorporation into clinical medicine.

Molecular aspects of restitution: functions of trefoil peptides

Healing of mucosal damage takes place in two phases: restitution of mucosal integrity and remodeling towards recreating the original glandular arrangements. These processes can be observed in several experimental rodent models: e.g., cryoprobe or NSAID-generated ulcers in the gastric or duodenal mucosa and following surgical resection of the small or large bowel. In some studies, it has been possible to detect changes in the expression of peptides, either in the reparative epithelium or adjacent to the damage, that may contribute to the healing processes. Trefoil peptides are expressed constitutively by epithelial cells in specific regions of the gastrointestinal tract, in association with mucins. Several studies have shown that trefoil peptide expression is enhanced at sites of damage in man and rat, and experimental evidence supports their active participation in the healing process. Recombinant trefoil peptides are able to enhance the rate of epithelial cell migration in vitro and are able to protect against indomethacin-induced damage in vivo, yet they do not depend upon TGF-beta for enhancing cell migration and do not appear to affect acid secretion. The mode of action of trefoil peptides appears to be receptor-mediated but is not simple. There is good evidence that there are interactions between members of the trefoil family and the EGF family that are beneficial for mucosal defense and repair. This raises the possibility that combining trefoil peptides with other growth factors or small molecules may be advantageous for treatment of ulceration.

Inhibitory effects of magnoshinin and magnosalin, compounds from "Shin-i" (Flos magnoliae), on the competence and progression phases in proliferation of subcultured rat aortic endothelial cells

Anti-proliferative effects of magnoshinin and magnosalin derived from "Shin-i" (Flos magnoliae) were investigated using subcultured endothelial cells (EC) of rat aorta. The inhibitory effects of magnoshinin were 2-fold greater at 10 micrograms/ml than that of magnosalin on the increase in cell number when EC were stimulated by 5% fetal bovine serum. In the 3H-thymidine incorporation monitored at 3 hr-intervals, magnoshinin (0.1-3 micrograms/ml) prolonged the starting time of DNA synthesis and reduced the rate of incorporation into EC. Magnosalin (0.3-3 micrograms/ml) reduced only the incorporation rate. These results suggest that magnoshinin inhibits both the competence phase and progression phase, but magnosalin preferentially inhibits the progression phase in EC proliferation.