Recombinant human transforming growth factor beta 3 accelerates gastric ulcer healing in rats

Components study on gastroprotective effect and holistic mechanism of the herbal pair Alpinia officinarum - Cyperus rotundus based on spectrum-effect relationship and integrated transcriptome and metabolome analyses

ETHNOPHARMACOLOGICAL RELEVANCE

The herbal pair Alpinia officinarum-Cyperus rotundus (HPAC) has an extended history of use in the treatment of gastric ulcers, and its curative effect is definite.

AIM OF THE STUDY

To explore the material basis and holistic mechanism of HPAC on ethanol-induced gastric ulcers.

MATERIALS AND METHODS

Three chemometrics, GRA, OPLS, and BCA, were used to construct the spectrum-effect relationship between the HPLC fingerprints of HPAC extracts and the bioactivity indices (cell viability; the levels of TNF-α, IL-6, COX-2, and PGE2; and wound healing rate) against GES-1 cell damage to screen the bioactive ingredients. The bioactive components were isolated and validated in vitro. Simultaneously, the effects of HPAC with concentrated bioactive ingredients was tested on ethanol-induced gastric ulcers in vivo, and the mechanism was investigated using transcriptomics and metabolomics. The mechanism was further validated by Western blotting. Finally, the contents of the main components of HPAC were determined before and after compatibility.

RESULTS

Twelve bioactive components were screened, and the structures of nine compounds were confirmed. An in vitro verification test showed that DPHA and galangin could protect GES-1 cells from injury, and that their content increased after compatibility. The CH2Cl2 fraction of HPAC (HP-CH2Cl2) can protect mice from ethanol-induced gastric mucosal injury by reducing hemorrhage and decreasing inflammatory cell infiltration. Western blot analysis indicated that this fraction may up-regulate TRPV1 protein and down-regulate PI3K and AKT proteins.

CONCLUSIONS

DPHA and galangin may be the bioactive components against ethanol-induced GES-1 cell injury. HP-CH2Cl2 may exert gastroprotective effects by regulating PI3K, AKT and TRPV1 proteins.

Suppressed Gastric Mucosal TGF-beta1 Increases Susceptibility to H. pylori-Induced Gastric Inflammation and Ulceration: A Stupid Host Defense Response

BACKGROUND/AIMS

Loss of transforming growth factor beta1 (TGF-beta1) exhibits a similar pathology to that seen in a subset of individuals infected with Helicobacter pylori, including propagated gastric inflammation, oxidative stress, and autoimmune features. We thus hypothesized that gastric mucosal TGF-beta1 levels could be used to determine the outcome after H. pylori infection.

METHODS

Northern blot for the TGF-beta1 transcript, staining of TGF-beta1 expression, luciferase reporter assay, and enzyme-linked immunosorbent assay for TGF-beta1 levels were performed at different times after H. pylori infection.

RESULTS

The TGF-beta1 level was markedly lower in patients with H. pylori-induced gastritis than in patients with a similar degree of gastritis induced by nonsteroidal anti-inflammatory drugs. There was a significant negative correlation between the severity of inflammation and gastric mucosal TGF-beta1 levels. SNU-16 cells showing intact TGF-beta signaling exhibited a marked decrease in TGF-beta1 expression, whereas SNU-638 cells defective in TGF-beta signaling exhibited no such decrease after H. pylori infection. The decreased expressions of TGF-beta1 in SNU-16 cells recovered to normal after 24 hr of H. pylori infection, but lasted very spatial times, suggesting that attenuated expression of TGF-beta1 is a host defense mechanism to avoid attachment of H. pylori.

CONCLUSIONS

H. pylori infection was associated with depressed gastric mucosal TGF-beta1 for up to 24 hr, but this apparent strategy for rescuing cells from H. pylori attachment exacerbated the gastric inflammation.

In vivo effects of TGFbeta1 on the growth of gastric epithelium in suckling rats

As the content of Transforming Growth Factor-beta (TGFbeta) wanes in the milk of lactating rat, an increase in TGFbeta is observed in the gastric epithelia concomitant with differentiation of the glands upon weaning. Whereas TGFbeta has been shown to inhibit the proliferation of gastrointestinal cells in vitro, its functional significance and mechanisms of action have not been studied in vivo. Therefore, we administered TGFbeta1 (1 ng/g body wt.) to 14-day-old rats in which the gastric epithelium was induced to proliferate by fasting, and determined the involvement of signaling through Smads and the impact on epithelial cell proliferation and apoptosis. After the gavage, we observed the progressive increase of active TGFbeta1 while TbetaRII-receptor remained constant in the gastric mucosa. By immunohistochemistry, we showed Smad2/3 increase at 60 min (p<0.05) and Smad2 phosphorylation/activation and translocation to the nucleus most prominently between 0 and 30 min after treatment (p<0.05). Importantly, TGFbeta1 inhibited cell proliferation (p<0.05), which was estimated by BrDU pulse-labeling 12 h after gavage. Lower proliferation was reflected by increased p27(kip1) at 2 h (p<0.05). Also, TGFbeta1 increased apoptosis as measured by M30 labeling at 60 and 180 min (p<0.001), and by morphological features at 12 h (p<0.05). In addition, we observed higher levels of activated caspase 3 (17 kDa) from 0 to 30 min. Altogether, these data indicate a direct effect of TGFbeta1 signaling through Smads on both inhibiting proliferation, through alteration of cycle proteins, and inducing apoptosis of gastric epithelial cells in vivo. Further, the studies suggest a potential role for both milk and tissue-expressed TGFbeta1 in gastric growth during postnatal development.

Experimental manipulation of transforming growth factor-beta isoforms significantly affects adhesion formation in a murine surgical model

Transforming growth factor-beta (TGF-beta), a multifunctional growth factor, represents three mammalian isoforms, TGF-beta1, TGF-beta2, and TGF-beta3. In cutaneous wound healing, combined neutralization of TGF-beta1 and -beta2 or addition of TGF-beta3 reduces scar formation. Here, we investigated whether experimental manipulation of TGF-beta isoforms reduced adhesion formation after injury to the peritoneum. Adhesions were produced in mice by surgical abrasion of adjacent serosa followed by close apposition. In the first part of this study, a detailed analysis of TGF-beta isoform distribution was performed through immunolocalization. TGF-beta isoforms clearly showed a unique temporal and spatial pattern of expression after peritoneal wounding. Based on this pharmacokinetic data, we next administered neutralizing antibodies to TGF-beta1 and -beta2 or exogenous TGF-beta3 peptide by local application and intraperitoneal injection at various times before and after surgery. At day 7 after surgery, addition of neutralizing antibodies to both TGF-beta1 and -beta2 significantly reduced the number and size of adhesions (P < 0.05) compared with the vehicle control. By contrast, exogenous addition of TGF-beta3 either had no effect or increased adhesion formation compared to the vehicle control. In conclusion, these results show that by blocking both TGF-beta1 and TGF-beta2 using neutralizing antibodies, it is possible to prevent abdominal adhesion formation.

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Genetic susceptibility to keloid disease: mutation screening of the TGFβ3 gene

Keloid disease (KD) is a fibroproliferative dermal tumour of unknown aetiology. The increased familial clustering in KD, its increased prevalence in certain races and its presence in identical twins suggest a strong genetic predisposition to keloid formation. Transforming growth factor beta isoforms (TGFbeta) play a central role in wound healing and fibrosis and have been implicated in KD pathogenesis. Recent data has suggested that TGFbeta(3) has an important role in scar formation. There is little known about the genetic variation present within the TGFbeta(3) gene, which contains seven exons and six introns spanning 43,000 base pairs of the human genome. Exons one to seven and the promoter region (1000 bp upstream from exon 1 in the 5'-flanking regions) were screened in 95 Caucasian KD cases and 95 Caucasian controls for the presence of novel mutations using a high throughput DHPLC mutation detection technology. There were no mutations identified in any of the exonic regions, however, multiple nondisease associated mutations were found in the promoter region of the TGFbeta(3) gene. These data demonstrate that there is no association between the exonic and promoter regions of TGFbeta(3) gene and keloid scarring in our cohort of Caucasian patients.

Expression patterns of transforming growth factor-beta and its receptors in gastric mucosa of patients with refractory gastric ulcer

AIM: Transforming growth factor-β (TGF-β) plays a regulatory role in tissue repair. In a previous study, we found that TGF-β and its receptors were expressed in gastric mucosa of patients with well-healed gastric ulcers, as demonstrated by immunohistochemistry. To further characterize the role of TGF-β and its receptors in repairing gastric ulcers, we investigated the expression patterns of TGF-β and its receptors in gastric mucosa by in situ hybridization and reverse transcriptase-polymerase chain reaction (RT-PCR).

METHODS: Seventy-four patients with endoscopically proven gastric ulcers were eligible for participation in this study. All patients had routine biopsies on initial endoscopy and were then treated for 12 wk with an H2 blocker. Repeat endoscopy was then performed. There were 8 patients with poorly healed ulcers, and biopsies were taken from the margin of the residual ulcers. These tissue samples, along with biopsy of gastric mucosa near the original ulcers from 8 randomly selected patients with well-healed ulcers were examined for TGF-β and TGF-β receptor II mRNA by RT-PCR and in situ hybridization, as well as immunohistochemistry.

RESULTS: TGF-β and TGF-β receptor II were strongly expressed in tissues from patients with well-healed ulcers. Four of the 8 patients with poor healing had low or absent expression of TGF-β or TGF-β receptor II mRNA. All cases positive by RT-PCR assay were confirmed by in situ hybridization as well as immunohistochemistry.

CONCLUSION: It is suggested that TGF-β and its receptors are important for gastric ulcer healing. These results may have implications for further investigation of the healing process and in predicting response to therapy.

Dermal fibroblast-associated gene induction by asiaticoside shown in vitro by DNA microarray analysis

BACKGROUND

Asiaticoside, isolated from Centella asiatica, promotes fibroblast proliferation and extracellular matrix (ECM) synthesis in wound healing. The precise mechanism, however, in molecular and gene expression levels is still unclear.

OBJECTIVE

Using cDNA microarray technology, the alteration of gene expression profiles was determined for human dermal fibroblasts in vitro in the presence of asiaticoside (30 microg mL(-1)). Fifty-four genes, with known functions for cell proliferation, cell cycle progression and synthesis of ECM, were significantly upregulated in our 'genome-nest' expression profile at various time points. Furthermore, the mRNA levels and protein production of certain genes responsible for ECM synthesis (e.g. encoding type I and type III collagen proteins) were evaluated by Northern blot and radioimmunoassay, respectively.

RESULTS

We found that there is a close correlation between the gene profile, mRNA and protein production in the response of the cells to asiaticoside stimulation.

CONCLUSIONS

This information could be used for exploring the response of the target genes to asiaticoside in fibroblasts.

Norepinephrine-induced changes in cardiac transforming growth factor-beta isoform expression pattern of female and male rats

Transforming growth factor-beta (TGF-beta) is a ubiquitous growth-regulating protein with an essential role in tissue repair and formation of extracellular matrix (ECM). To better understand the role of different isoforms of TGF-beta in the cardiac remodeling process induced by norepinephrine (NE), the expression of TGF-beta1, TGF-beta2, and TGF-beta3 was studied and compared with the expression of collagen. NE (0.1 mg/kg. h) was intravenously infused in female and male Sprague-Dawley rats for several time periods, and freshly obtained ventricular myocardium after 1 day was dissociated into myocyte and nonmyocyte fractions. Prazosin (0.1 mg/kg x h) and metoprolol (1 mg/kg. h) were used to block alpha- and beta-adrenoceptors, respectively. After NE infusion, the three isoforms of TGF-beta were differentially induced as far as the magnitude and the time course is concerned. The increased expression of TGF-beta2 started earlier with a maximum after 12 hours and was more pronounced (10-fold elevation) than that of the other two isoforms, with a clear specificity for the left ventricle in female hearts. This specificity was also seen in male rats with 16-fold elevation of TGF-beta2 after 1 day of NE-stimulation. The increase of TGF-beta2 was significant only in the myocyte fraction obtained from female as well as from male hearts. The expression of the mRNA of all TGF-beta isoforms of collagen type I and type III, and of the matrix metalloproteinase (MMP)-2 and its inhibitor TIMP-2 was reduced predominantly by alpha-adrenoceptor blockade with prazosin. The increase in TGF-beta isoforms correlated with that of the mRNA expression of collagens, MMP-2 and TIMP-2.

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.

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.

Changes in extracellular matrix and in transforming growth factor beta isoforms after coronary artery ligation in rats

Extensive myocardial remodeling occurs after transmural myocardial infarction (MI). The infarcted myocardium is being replaced by scar tissue after gradual resorption of the necrotic tissue. The remodeling process involves both synthesis and degradation of collagens as major components of the extracellular matrix (ECM). In the present study we have analyzed the time-dependent changes of the processes related to this fibrosis in the infarct area and in the non-infarcted left ventricle (LV) six hours to 82 days after occlusion of the left anterior descending coronary artery (LAD) in rats. We also examined whether changes occurred in the expression pattern of the transforming growth factor (TGF) beta isoforms, since this cytokine is known as powerful inductor of fibrosis. Elevation in colligin expression preceded the pronounced increase in mRNA expression of both type I and type III collagen after MI from day three onwards. The maximal increase in colligin protein in the infarct area coincided with the most pronounced expression of collagen I and collagen III mRNA expression. Also, the expression and activity of matrix metalloproteinases (MMPs) and of tissue inhibitor of matrix metalloproteinase (TIMP)-2 mRNA were increased predominantly in the infarct area. TGF beta(1)and TGF-beta(2)expression increased within the first days after MI, whereas TGF-beta(3)expression was elevated predominantly in the infarct area. This pronounced increase in TGF-beta(3)persisted up to 82 days and correlated positively with the parameters of ECM metabolism. Thus, the scar formation is an ongoing dynamic process in which TGF-beta(3)seems to play an active role in the complex ventricular remodeling.

TGF-beta3 in the treatment of pressure ulcers: a preliminary report

OBJECTIVE

To determine the safety, tolerability, and efficacy of TGF-beta3 in the treatment of chronic, nonhealing pressure ulcers.

DESIGN

A subset analysis of data from a randomized, blind, parallel, placebo-controlled trial involving 270 patients.

SETTING

University of Michigan Wound Care Center.

PATIENTS

A total of 14 patients (6 women and 8 men aged > or = 18 years) with pressure ulcers were randomly assigned to 1 of 3 groups to receive once daily topical application of recombinant TGF-beta3 or placebo gel for a period of no more than 16 weeks. Group 1 (n=4) received 1.0 microg/cm2 of TGF-beta3, Group 2 (n=5) received 2.5 microg/cm2 of TGF-beta3, and Group 3 (n=5) received placebo gel. All subjects received standardized wound care as well. Weekly evaluations were performed for efficacy, determined by relative wound surface areas and volumes, and were compared with initial baseline values and safety parameters.

MAIN OUTCOME MEASURE

Reduction in pressure ulcer area and volume.

MAIN RESULTS

Group 2 had a significantly increased rate of wound healing at the fourth visit (P<.05). No significant difference was observed in the healing rate among the groups at the termination of the study. Treatment with TGF-beta3 was well tolerated and there were no significant adverse reactions.

CONCLUSION

The findings of this study indicate that the topical application of TGF-beta3 is safe and useful in the treatment of pressure ulcers and is most effective at the earliest stages of therapy.

Improved airway healing using transforming growth factor beta-3 In a rabbit model

Laryngeal wound healing is essential following laryngotracheal surgery. Patients with poor wound healing develop poor epithelial closure and increased granulation tissue which cause a stenosis of the repaired airway. Transforming growth factor-beta3 has been shown to enhance wound healing in cutaneous wounds, but has never been used in the airway. This study utilized a rabbit laryngeal wound-healing model that has been shown to be reproducible with limited morbidity. Thirty-four rabbits underwent a cricoid-split operation with collagen sponge insertion. All animals were classified randomly into three groups: local administration of placebo (Group G1, n = 13), 0.18 microg transforming growth factor-beta3 (Group G2, n = 11) and of 1.0 microg transforming growth factor-beta3 (Group G3, n = 10). All animals survived the postoperative period without respiratory distress. The airway was harvested six days after surgery and assessed by light microscopy. Histologic evidence for healing was subjectively graded by two blinded, independent investigators, and the results were statistically analyzed for significance. A significant improvement in the epithelial closure (p < 0.01) and subepithelial connective tissue closure (p < 0.005) was found in the 1.0 microg transforming growth factor-beta3 group (G3) compared with the placebo group (G1). Analysis of the 0.18 microg transforming growth factor-beta3 group (G2) did not reveal any significant differences compared with the placebo group (G1). These results suggest an application for transforming growth factor-beta3 in accelerating wound healing in the larynx.

Synthesis, development and in vitro evaluation of drug delivery systems with protective effect against degradation by pepsin

A (poly)peptide drug delivery system providing a protective effect against degradation by pepsin has been generated. A simplified pepstatin analogue was thereby synthesised displaying a terminally located primary amino group allowing an easy covalent attachment to anionogenic mucoadhesive polymers by the formation of amide bonds. The IC50 of this novel inhibitor was determined to be 6.65+/-1.05x10(-6) M. Mediated by a carbodiimide it was covalently bound to polycarbophil and sodium carboxy-methyl cellulose (NaCMC). In contrast to polycarbophil-inhibitor conjugates, NaCMC-inhibitor conjugates displayed a high inhibitory effect towards pepsin. The protective effect of tablets containing a NaCMC-pepsin inhibitor conjugate (10%), NaCMC (56.7%), insulin (3.3%), and mannitol (30%) was evaluated in vitro. Tablets were therefore incubated for 2 h at 37 degrees C with simulated gastric fluid according to the Pharmacopoeia Europea. Following analysis demonstrated that 50.8+/-8.6% (mean +/- SD; n = 3) of insulin were degraded within the swollen carrier matrix, whereas insulin was completely metabolised in tablets without the NaCMC-pepsin inhibitor conjugate. This protective effect against degradation by pepsin might make such dosage forms useful tools for a targeted (poly)peptide delivery to the stomach.