Quality of gastric ulcer healing: histological and ultrastructural assessment

Treatment of gastric ulcer, traditional Chinese medicine may be a better choice

ETHNOPHARMACOLOGICAL RELEVANCE

Gastric ulcer (GU) is the injury of the gastric mucosa caused by the stimulation of various pathogenic factors penetrating the deep mucosal muscle layer. An increasing number of studies have shown that traditional Chinese medicine (TCM) is highly effective in treating GU due to its multitarget, multilevel, and multi-pathway effects.

AIM OF THE STUDY

To review the latest research progress in the treatment of GU by TCM, including clinical and experimental studies, focusing on the target and mechanism of action of drugs and providing a theoretical basis for the treatment of GU by natural herbs.

MATERIALS AND METHODS

Electronic databases (PubMed, Elsevier, Springer, Web of Science, and CNKI) were searched using the keywords "gastric ulcer", "gastric mucosal lesion", "TCM" and or paired with "peptic ulcer" and "natural drugs" for studies published in the last fifteen years until 2023.

RESULTS

TCM, including single components of natural products, Chinese patent medicines (CPM), and TCM decoction, is expected to treat GU by regulating various mechanisms, such as redox balance, inflammatory factors, angiogenesis, gastric mucosal protective factors, intestinal flora, apoptosis, and autophagy.

CONCLUSIONS

We discussed and summarized the mechanism of TCM in the treatment of GU, which provided a sufficient basis for TCM treatment of GU.

Gut homeostasis, injury, and healing: New therapeutic targets

The integrity of the gastrointestinal mucosa plays a crucial role in gut homeostasis, which depends upon the balance between mucosal injury by destructive factors and healing via protective factors. The persistence of noxious agents such as acid, pepsin, nonsteroidal anti-inflammatory drugs, or Helicobacter pylori breaks down the mucosal barrier and injury occurs. Depending upon the size and site of the wound, it is healed by complex and overlapping processes involving membrane resealing, cell spreading, purse-string contraction, restitution, differentiation, angiogenesis, and vasculogenesis, each modulated by extracellular regulators. Unfortunately, the gut does not always heal, leading to such pathology as peptic ulcers or inflammatory bowel disease. Currently available therapeutics such as proton pump inhibitors, histamine-2 receptor antagonists, sucralfate, 5-aminosalicylate, antibiotics, corticosteroids, and immunosuppressants all attempt to minimize or reduce injury to the gastrointestinal tract. More recent studies have focused on improving mucosal defense or directly promoting mucosal repair. Many investigations have sought to enhance mucosal defense by stimulating mucus secretion, mucosal blood flow, or tight junction function. Conversely, new attempts to directly promote mucosal repair target proteins that modulate cytoskeleton dynamics such as tubulin, talin, Ehm², filamin-a, gelsolin, and flightless I or that proteins regulate focal adhesions dynamics such as focal adhesion kinase. This article summarizes the pathobiology of gastrointestinal mucosal healing and reviews potential new therapeutic targets.

The Critical Role of Growth Factors in Gastric Ulcer Healing: The Cellular and Molecular Mechanisms and Potential Clinical Implications

In this article we review the cellular and molecular mechanisms of gastric ulcer healing. A gastric ulcer (GU) is a deep defect in the gastric wall penetrating through the entire mucosa and the muscularis mucosae. GU healing is a regeneration process that encompasses cell dedifferentiation, proliferation, migration, re-epithelialization, formation of granulation tissue, angiogenesis, vasculogenesis, interactions between various cells and the matrix, and tissue remodeling, all resulting in scar formation. All these events are controlled by cytokines and growth factors (e.g., EGF, TGFα, IGF-1, HGF, bFGF, TGFβ, NGF, VEGF, angiopoietins) and transcription factors activated by tissue injury. These growth factors bind to their receptors and trigger cell proliferation, migration, and survival pathways through Ras, MAPK, PI3K/Akt, PLC-γ, and Rho/Rac/actin signaling. The triggers for the activation of these growth factors are tissue injury and hypoxia. EGF, its receptor, IGF-1, HGF, and COX-2 are important for epithelial cell proliferation, migration, re-epithelialization, and gastric gland reconstruction. VEGF, angiopoietins, bFGF, and NGF are crucial for blood vessel regeneration in GU scars. The serum response factor (SRF) is essential for VEGF-induced angiogenesis, re-epithelialization, and blood vessel and muscle restoration. Local therapy with cDNA of human recombinant VEGF165 in combination with angiopoietin1, or with the NGF protein, dramatically accelerates GU healing and improves the quality of mucosal restoration within ulcer scars. The future directions for accelerating and improving healing include local gene and protein therapies with growth factors, their combinations, and the use of stem cells and tissue engineering.

Short-chain fatty acid butyrate: A novel shield against chronic gastric ulcer

Butyrate is one of the most abundant short-chain fatty acids produced by intestinal bacteria. In the present study, the action of butyrate on chronic gastric mucosa lesions was investigated, as well as its underlying mechanism in mice. Male mice from the Institute of Cancer Research were randomly divided into three groups: Sham, model and butyrate groups. Butyrate was administered intragastrically for 7 days to butyrate group mice following the establishment of a gastric ulcer model. Hematoxylin and eosin staining, immunohistochemical analysis, enzyme-linked immunosorbent assay and quantitative polymerase chain reaction were used to determine the therapeutic effects and molecular mechanism of butyrate treatment. The findings demonstrated that butyrate induced a marked shift in superoxide dismutase and catalase activities, along with a decrease in malondialdehyde levels, thereby attenuating oxidative stress. Furthermore, butyrate decreased the levels of pro-inflammatory cytokines interleukin-1β, tumour necrosis factor-α and leukotriene B4, which helped combat inflammatory responses. Moreover, butyrate treatment exerted remarkable positive influences that mediate an increase in 6-keto-PGF-1α (a degradation product of prostacyclin), trefoil factor 2, MUC5AC and fibroblast growth factor-7 levels to promote gastric mucosal repair. The expression of specific receptor GPR109A for butyrate was upregulated, with no significant difference noted in the expression of GPR43 or GPR41. Overall, the present findings revealed that butyrate exerted therapeutic effects by upregulating mucosal repair factors and stimulating protective responses against oxidation and inflammation. GPR109A may be the key receptor for butyrate therapy.

Ulcer healing and mechanism(s) of action involved in the gastroprotective activity of fractions obtained from Syngonanthus arthrotrichus and Syngonanthus bisulcatus

Background

Syngonanthus arthrotrichus and Syngonanthus bisulcatus, currently known for Comanthera aciphylla (Bong.) L.R.Parra & Giul. and Comanthera bisulcata (Koern.) L.R. Parra & Giul, popularly known in Brazil as “sempre-vivas,” are plants from the family Eriocaulaceae. They are found in the states of Minas Gerais and Bahia. The species are known to be rich in flavonoids to which their gastroprotective activity has been attributed. In this research, experimental protocols were performed to elucidate the associated mechanisms of action.

Methods

The activity was evaluated using induced gastric ulcer models (acetic acid and ethanol-induced gastric lesions in NEM or L-NAME pre-treated mice, and by ischemia/reperfusion). Antioxidant enzymes, serum somatostatin, and gastrin were also evaluated.

Results

In chronic gastric ulcers, a single daily oral dose of Sa-FRF or Sb-FRF (100 mg/kg body wt.) for 14 consecutive days accelerated ulcer healing to an extent similar to that seen with an equal dose of cimetidine. The pre-treatment of mice with NEM (N-ethylmaleimide) or L-NAME (N-nitro-L-arginine) abolished the protective activity of Sa-FRF, Sa-FDF, Sb-FDF and Sb-FRF or Sa-FRF and Sb-FRF, respectively, which indicates that antioxidant compounds and nitric oxide synthase activity are involved in the gastroprotective. Sa-FRF and Sb-FRF (100 mg/kg p.o) protected the gastric mucosa against ulceration that was induced by ischemia/reperfusion (72 and 76 %, respectively). It also decreased lipid peroxidation and restored total thiols in the gastric wall of mice that had been treated with ethanol. When administered to rats submitted to ethanol-induced gastric lesions, Sa-FRF and Sb-FRF (100 mg/kg, p.o.) increased the somatostatin serum levels, while the gastrin serum levels were proportionally decreased.

Conclusions

The results indicate significant healing effects and gastroprotective activity for the Sa-FRF and Sb-FRF, which probably involves the participation of SH groups, nitric oxide (NO), the antioxidant system, somatostatin, and gastrin. All are integral parts of the gastrointestinal mucosa’s cytoprotective mechanisms against aggressive factors.

Effect of persistent positive acceleration on the quality of ulcer healing in rats with experimental gastric ulcer

AIM: To investigate the effect of positive acceleration (+Gz) on gastric ulcer healing in rats and to explore the possible mechanisms involved.

METHODS: Thirty-two male SD rats were randomly and equally divided into a control group, a +5Gz exposure group, a +10Gz exposure group, and a +10Gz exposure plus KangFuXin solution group. Gastric ulcer was induced in rats with acetic acid. After 3 d, rats in the latter three groups were exposed to +Gz each other day for 1 wk (four times in all, five minutes each time). The rats in the +10Gz exposure plus KangFuXin solution group were additionally gavaged with 2 mL of KangFuXin solution every day for 1 wk. Tissue and bloods samples were taken to detect the contents of prostaglandin E2 (PGE2) in the gastric mucosa and calcitonin gene-related peptide (CGRP) in blood by radioimmunoassay and the content of nitric oxide (NO) in blood by nitrate reductase assay.

RESULTS: The higher +Gz, the thinner restored mucosa thickness and the more the number of cystically dilated glands. The contents of PGE2 in the gastric mucosa were significantly lower in the +10Gz exposure group than in the +5Gz exposure group, control group, and +10Gz exposure plus KangFuXin solution group (3.438 pg/mL ± 0.908 pg/mL vs 5.147 pg/mL ± 0.652 pg/mL, 6.986 pg/mL ± 0.743 pg/mL, 6.133 pg/mL ± 0.545 pg/mL, all P < 0.01). The contents of CGRP in blood were significantly lower in the +10Gz exposure group than in the +5Gz exposure group, control group, and +10Gz exposure plus KangFuXin solution group (62.254 pg/mL ± 15.943 pg/mL vs 78.333 pg/mL ± 11.290 pg/mL, 82.583 pg/mL ± 11.788 pg/mL, 78.455 pg/mL±12.645 pg/mL, all P < 0.05). The contents of NO in blood were significantly lower in the +10Gz exposure group than in the +5Gz exposure group, control group, and +10Gz exposure plus KangFuXin solution group (44.773 μmol/L ± 6.858 μmol/L vs 47.783 μmol/L ± 2.847 μmol/L, 53.806 μmol/L ± 9.272 μmol/L, 53.853 μmol/L ± 7.372 μmol/L, all P < 0.05).

CONCLUSION: Positive acceleration delays gastric ulcer healing in rats, and treatment with KangFuXin Solution can improve the quality of ulcer healing.

Quality of ulcer healing in gastrointestinal tract: Its pathophysiology and clinical relevance

In this paper, we review the concept of quality of ulcer healing (QOUH) in the gastrointestinal tract and its role in the ulcer recurrence. In the past, peptic ulcer disease (PUD) has been a chronic disease with a cycle of repeated healing/remission and recurrence. The main etiological factor of PUD is Helicobacter pylori (H. pylori), which is also the cause of ulcer recurrence. However, H. pylori-negative ulcers are present in 12%-20% of patients; they also recur and are on occasion intractable. QOUH focuses on the fact that mucosal and submucosal structures within ulcer scars are incompletely regenerated. Within the scars of healed ulcers, regenerated tissue is immature and with distorted architecture, suggesting poor QOUH. The abnormalities in mucosal regeneration can be the basis for ulcer recurrence. Our studies have shown that persistence of macrophages in the regenerated area plays a key role in ulcer recurrence. Our studies in a rat model of ulcer recurrence have indicated that proinflammatory cytokines trigger activation of macrophages, which in turn produce increased amounts of cytokines and chemokines, which attract neutrophils to the regenerated area. Neutrophils release proteolytic enzymes that destroy the tissue, resulting in ulcer recurrence. Another important factor in poor QOUH can be deficiency of endogenous prostaglandins and a deficiency and/or an imbalance of endogenous growth factors. Topically active mucosal protective and antiulcer drugs promote high QOUH and reduce inflammatory cell infiltration in the ulcer scar. In addition to PUD, the concept of QOUH is likely applicable to inflammatory bowel diseases including Crohn’s disease and ulcerative colitis.

Evaluation of antiulcerogenic activity of aqueous extract of Brassica oleracea var. capitata (cabbage) on Wistar rat gastric ulceration

CONTEXT: The cabbage (Brassica oleraceae var. capitata) is an herbaceous and leafy plant which belongs to the Brassicaceae family, native to coastal southern and Western Europe. Used in cooking for its nutritional value also has known anti-inflammatory activity. OBJECTIVE We studied the antiulcerogenic activity of aqueous extract of Brassica oleracea var. capitata (AEB) in order to validate ethnobotanical claims regarding the plant use in the gastric disorders. METHOD: Acute gastric ulcers were induced in rats by the oral administration of acetylsalicylic acid. The gastroprotective potential of the AEB (0.250, 0.500 and 1.000 mg.kg-1/body weight) was compared with omeprazole (20 mg.kg-1/body weight). RESULTS: The stomach analysis indicated that treatment with AEB inhibited the gastric damage. The gastroprotective activity as evidenced by its significant inhibition in the formation of ulcers induced by chemical agent with a maximum of 99.44% curation (250 mg.kg-1 body weight) in acetylsalicylic acid-induced ulcers. CONCLUSIONS: The AEB demonstrated good antiulcerogenic activities which justify the inclusion of this plant in the management of gastric disorders. Further experiments are underway to determine which antiulcer mechanisms involved in gastroprotection.

Can a Strychnos species be used as antiulcer agent? Ulcer healing action from alkaloid fraction of Strychnos pseudoquina St. Hil. (Loganiaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Strychnos pseudoquina St. Hil. (Loganiaceae) is one Brazilian native medicinal species described in the first edition of the Brazilian Official Pharmacopoeia in 1929. This medicinal plant, popularly known as "quina-quina", "quina-branca" or "casca aromatica was very commonly used in folk medicine in tea form obtained from the bark and/or leaves as tonic, antipyretic, antimalarial and mainly against diseases of the liver, spleen and stomach.

AIM OF THE STUDY

Previous study already characterized the gastroprotective action of this species The aim of the present study is to elucidate the mechanism of the healing process mediated by the methanolic extract (ME) and their enriched alkaloid fraction (EAF) from Strychnos pseudoquina in chronic gastric ulceration induced by 5% acetic acid in rats, an experimental model that accurately reflects human gastrointestinal disease.

MATERIAL AND METHODS

The ME and EAF was administered orally in a single dose (based on previously study of dose-response curve) for 14 days after chronic ulceration was induced in rats. The healing effect of ME and EAF was evaluated by macroscopic and morphometric analyses, immunohistochemical assay (PCNA and SOD) and anti-Helicobacter pylori effect was evaluated by in vitro assay.

RESULTS

Our results demonstrated that EAF significantly reduced border internal (42%) and external (38%) lesion area (mm(2)) by macroscopic analyses (P<0.05). Animals treated with EAF stimulated some proliferative factors by increasing the height of epithelial regenerative area and the expression of PCNA-positive nuclei. The number of vessels in gastric mucosa of rats treated with EAF reveals an expressive increase (4 times more than vehicle treatment) of vessels that stimulate cells proliferation in the healing region. These results suggest that the recovery of vascularization of the ulcerated area is involved in the healing action of alkaloid fraction of Strychnos pseudoquina. The MIC (minimum inhibitory concentration) of 75 μg/ml from EAF showed an effective in vitro anti-Helicobacter pylori action of this fraction. EAF also was quite effective in the process of SOD release that is an important protective factor against bacterial agents. The efficacy of EAF was accomplished safely without presenting any alteration of toxicological parameters during 14 day of treatment.

CONCLUSIONS

The expressive gastric healing effect by increasing cellular proliferation together with expression of SOD activity and antibacterial action against Helicobacter pylori confirm the efficacy of this species in heal gastric mucosa and these results are a important contribution to the knowledge of a crude drug presents at the Brazilian Official Pharmacopoeia since 1929.

Angiogenic and cell proliferating action of the natural diarylnonanoids, malabaricone B and malabaricone C during healing of indomethacin-induced gastric ulceration

PURPOSE

To evaluate the plant phenolics, malabaricone B (mal B) and malabaricone C (mal C) in healing stomach ulcer by modulating angiogenesis.

MATERIALS AND METHODS

Male Swiss albino mice, ulcerated with indomethacin (18 mg/kg, p. o., single dose) were treated up to 7 days with different doses of mal B or mal C. The healing capacities of the drugs and their effects on the angiogenic parameters were assessed.

RESULTS

Maximum ulceration, observed on the 3rd day after indomethacin administration was effectively healed by mal B and mal C (each 10 mg/kg, p. o. x 3 days), the latter showing equivalent potency (~78% p < 0.001) as that of Omez (3 mg/kg, p. o. x 3 days) and misoprostol (10 mug/kg, p. o. x 3 days). Compared to the untreated mice, those treated with mal B or mal C respectively for 3 days increased the mucosal EGF level (139 and 178%, p < 0.001), the serum VEGF level (56%, p < 0.01 and 95%, p < 0.001) and microvessels formation (37%, p < 0.05 and 62%, p < 0.01), while reducing the serum endostatin level (37%, p < 0.05 and 61%, p < 0.01). The relative healing capacities of mal B and mal C correlated well with their respective abilities to modulate the angiogenic factors. The healing by Omez and misoprostol was not due to improved angiogenesis.

CONCLUSIONS

The drugs, mal B and mal C could effectively heal indomethacin-induced stomach ulceration in mice by promoting angiogenesis.

Quality of gastric ulcer healing evaluated by endoscopic ultrasonography

AIM: To evaluate the quality of gastric ulcer healing after different antiulcer treatment by endoscopic ultrasonography (EUS).

METHODS: The patients were divided into three groups, and received lansoprazole, amoxicillin and clarithromycin for 1 wk. Then group A took lansoprazole combined with tepreton for 5 wk, group B took lansoprazole and group C took tepreton for 5 wk. Endoscopy and EUS were performed before and 6 wk after medication.

RESULTS: There was no significant difference in cumulative healing rate to S stage between the groups (89%, 82% vs 83%, P>0.05). The rate of white scar formation was significantly higher in group A than in groups B and C (67%, 36%, 50%, P<0.05). The average contraction rates of the width of ulcer crater, length of disrupted muscularis propria layer and hypoechoic area were higher in group A than in groups B and C (0.792±0.090, 0.660±0.105 vs 0.668±0.143, P<0.05). The hypoechoic area disappeared in four cases of group A, one of group B and two of group C. The percentage of hypoechoic area disappearance was higher in group A than in the other two groups (44%, 9% vs 17%, P<0.05). Gastric ulcer healing was better in group A.

CONCLUSION: The combined administration of proton-pump inhibitors and mucosal protective agent can improve gastric ulcer healing.

Matrix metalloproteinase gene expression in chronic gastric ulcer: a potential role of eosinophils in perforation

Gene expression of matrix degrading enzymes was investigated in surgical specimens of perforated gastric ulcers. In these ulcers, the inflammatory cells infiltrating into the granulation tissue were granulocytes, particularly eosinophils. The extracellular matrix of the stomach wall consists mainly of collagen types I and III, which are selectively degraded by matrix metalloproteinase-1 (MMP-1). MMP-1 mRNA was detected in the cytoplasm of infiltrating cells, suggesting that eosinophils play an important role in ulcer recurrence and in perforation of the stomach wall. The degree of eosinophil infiltration into an ulcer base may be a useful marker for the risk of perforation. Patients showing this marker may benefit from a prophylactic therapy for preventing severe complications. The control of MMP gene expression represents a potential strategy for the treatment of recurrent gastric ulcer.

Histological evaluation of connective tissue components in the healing process of human gastric ulcer

1. The aim of the present study was the evaluation of human gastric ulcer healing and intractability from the viewpoint of connective tissue components. 2. Based on investigations of clinical status, we divided 78 patients with a gastric ulcer into three groups. All patients underwent gastrectomy and group I consisted of 17 patients operated on for bleeding or perforation, group II consisted of 37 patients operated on for an accompanying gastric carcinoma and group III consisted of 24 patients operated on for ulcer intractability. 3. We evaluated, in resected specimens, angiogenesis by Azan-Mallory staining and fibroplasia by applying proliferating cell nuclear antigen (PCNA) immunostaining. The inflammatory grade and fibrosis at the ulcer base were also evaluated by haematoxylin-eosin and Azan-Mallory staining. 4. Microvessel counts in group III were significantly lower than those in group I and II (P < 0.05). The PCNA labelling index of fibroblasts in group III was significantly lower than that in groups I and II (P < 0.05). The inflammatory grade was severe and fibrosis was excessive in group III. 5. From these results, it is suggested that the reduced angiogenesis and decline in fibrous cell proliferation are important factors contributing to gastric ulcer intractability.

Quality of gastric ulcer healing. Is it influenced by antiulcer drugs?

BACKGROUND

Chronic administration of sucralfate (SCR), a non-systemic ulcer-healing drug, exerts a trophic action on the gastric mucosa and prevents or reduces ulcer recurrence. The aim of this study was to determine whether SCR and/or the acid inhibiting drug omeprazole (OME) may affect the quality of ulcer healing, i.e., restoration of mucosal architecture.

METHODS

Gastric ulcers were produced in male rats by serosal application of acetic acid. Rats were gavaged twice daily for 14 days with 2 ml of: (a) Placebo (PLA), (b) SCR 500 mg/kg, or (c) OME, 50 mg/kg starting 48 h after ulcer induction. We determined ulcer size under a dissecting microscope, and performed quantitative histologic assessment of quality of healing score (QS) on a scale from 0 (normal) to 5 (most abnormal).

RESULTS

Ulcer size was 1.4 +/- 0.15 mm in the PLA group, 0.61 +/- 0.1 mm in the SCR group and 0.86 +/- 0.13 mm in the OME group (both OME and SCR p < 0.01 versus PLA). In the PLA group, histology showed (in rats with ulcers) a well-developed ulcer margin with cystically dilated glands. The QS of the ulcer scar in the PLA group was 3.3 +/- 0.22. IN the SCR-treated group, within the scar gastric glands were less dilated, more vertically oriented and the healing zone and granulation tissue were well developed and organized. The QS was 1.6 +/- 0.2, p < 0.001 versus PLA and OME. In the OME group, the ulcer margin and the scar were thinner-reduction of mucosal thickness by 43 +/- 2% (p < 0.005) and 18 +/- 1%, respectively, versus SCR and PLA groups. The number of dilated glands and connective tissue components in the scar was increased by 60%. The QS was 3.6 +/- 0.3.

CONCLUSIONS

(1) Both SCR and OME significantly reduced the size of the experimental gastric ulcer. (2) Restoration of mucosal architecture, assessed quantitatively, was much better in the SCR than in the OME and PLA-treated groups. (3) a trophic action of SCR on the gastric mucosa may be the basis of better quality of ulcer healing with SCR.