Interaction of growth hormone-releasing factor and somatostatin on ulcer healing and mucosal growth in rats: role of gastrin and epidermal growth factor

Growth hormone-releasing factor (GRF) was reported to possess the growth-promoting action on the gastroduodenal mucosa that can be augmented by removal of endogenous somatostatin. Since mucosal proliferation was considered to contribute to healing of chronic gastroduodenal ulcerations, we designed the study to determine the interaction of GRF and somatostatin on the healing rate of acetic acid-induced chronic gastric and duodenal ulcers and on the growth of gastroduodenal mucosa in rats. GRF injected subcutaneously twice daily at 100 micrograms/kg/day for 7 days resulted in a significant enhancement of healing rate of both gastric and duodenal ulcerations and this was accompanied by a significant increase in the weight of the mucosa and the contents of RNA and DNA. GRF also significantly increased serum gastrin levels and the tissue contents of epidermal growth factor (EGF) in salivary glands, duodenum and pancreas, suggesting that both gastrin and EGF could contribute to mucosal trophic and ulcer healing effects of GRF. Somatostatin (100 micrograms/kg/day for 7 days) abolished almost completely the ulcer healing and mucosal growth-promoting effects of GRF and this was accompanied by the reduction in serum gastrin level and the tissue contents of EGF suggesting that the suppression of gastrin and EGF release could contribute to the observed effects of somatostatin. We conclude that GRF has both the ulcer healing and the mucosal trophic actions which can be antagonized by somatostatin and that gastrin and EGF may be implicated in these actions.     

The role of the antrum and the vagus nerve in the metabolism of histamine in the human gastric mucosa.

The effects of antrectomy and proximal gastric vagotomy on the metabolism of histamine in the human gastric mucosa were studied in the basal state and during pentagastrin stimulation in patients with duodenal or gastric ulcer disease. Mucosal biopsy specimens were taken from the antral and oxyntic gland areas, whereafter histamine content, histidine decarboxylase activity, and histamine methyltransferase activity were simultaneously assayed. Vagotomy was followed by a decrease in the acid secretory capacity and an increase in basal serum gastrin levels. Histamine content of the oxyntic mucosa increased after vagotomy, but the ability of pentagastrin to form new amounts of the amine was impaired. Antrectomy caused a decrease in acid secretion and a fall in gastrin concentrations. Basal histamine content and rate of amine formation in the remaining oxyntic mucosa were unaffected by antrectomy. Antrectomy impaired the ability of pentagastrin to release histamine. Histamine methyltransferase was not affected by pentagastrin, vagotomy, or antrectomy. In conclusion, both antral gastrin and the vagus nerve seem to exert a regulatory influence on the metabolism of histamine in the human oxyntic mucosa. The withdrawal of these factors either causes impaired ability of pentagastrin to release histamine from its storage site or counteracts the ability of pentagastrin to accelerate histamine synthesis.     

Effect of cholecystokinin and 16,16-dimethyl prostaglandin E2 on RNA and DNA of gastric and duodenal mucosa.

Fasted rats were injected with either cholecystokinin-octopeptide (CCK-OP), 20 mug per kg; 16,16-dimethyl prostaglandin E2 (16,16-dimethyl PGE2), 0.2 mg per kg; pentagastrin, 250 mug per kg, or saline every 8 hr for 48 hr. The rats were killed and the incorporation of [3H]thymidine into DNA as well as the total DNA and RNA content of the mucosa of the oxyntic gland area and the duodenum were determined. Pentagastrin increased DNA synthesis 60% (P less than 0.001) in gastric mucosa and 90% (P less than 0.001) in duodenal mucosa when compared with rates for saline controls. Neither CCK-OP nor 16,16-dimethyl PGE2 altered gastric mucosal DNA synthesis. Pentagastrin significantly increased the DNA and RNA content of both the gastric and duodenal mucosa. CCK-OP and 16,16-dimethyl PGE2 caused a slight but significant increase in duodenal DNA synthesis, CCK-OP did not significantly increase duodenal DNA content, and 16,16-dimethyl PGE 2 increased duodenal RNA but not DNA content. CCK-OP (20 mug per kg) in combination with pentagastrin did not alter the stimulation of gastric DNA synthesis but significantly decreased the effect of pentagastrin on duodenal DNA. A dose of CCK-OP (370 mug per kg) equimolar to 250 mug per kg of pentagastrin did not stimulate DNA synthesis in either tissue and significantly inhibited stimulation by pentagastrin in both tissues. Low doses of CCK-OP (2.5, 5.0, 10.0, 20.0 mug per kg) caused statistically significant increases in DNA synthesis and DNA content of the pancreas, but had no effect on either mucosa of the oxyntic gland area or duodenum. 16,16-Dimethyl PGE2 did not inhibit the stimulation of DNA synthesis or the increases in DNA and RNA content stimulated by pentagastrin. From these results it appears that: (1) moderate doses of CCK have a weak trophic effect in the duodenum but not in the stomach, (2) physiological doses of CCK-OP stimulated pancreatic DNA synthesis and increased pancreatic DNA content without affecting these parameters in the oxyntic gland area or duodenum in the same animals, (3) in the stomach and duodenum CCK is not as potent a trophic hormone as gastrin and inhibits, probably competitively, the trophic effects of gastrin, (4) 16,16-dimethyl PGE2 does not stimulate growth and does not interfere with the trophic response to gastrin even though it inhibits acid secretion, and (5) 16,16-dimethyl PGE2 increased the RNA content of duodenal mucosa indicating that it may stimulate activity resulting in hypertrophy.     

Acid, pepsin, and mucus secretion in patients with gastric and duodenal ulcer before and after colloidal bismuth subcitrate (De-Nol).

Basal and pentagastrin stimulated gastric secretion was measured in seven patients with duodenal, and six with gastric ulcers before and after four weeks' treatment with colloidal bismuth subcitrate (as De-Nol), one tablet four times a day. Each duodenal and all but one of the gastric ulcers healed. After De-Nol there were no significant changes in basal, or pentagastrin stimulated volume, acid output, or primary parietal component. There were marked decreases in basal (duodenal ulcer -25%; gastric ulcer -16%) and pentagastrin stimulated total pepsin outputs, (duodenal ulcer -42%, gastric ulcer -36%). There were insignificant decreases in basal output of mucus, but postpentagastrin stimulated mucus output was significantly inhibited (p less than 0.05) in patients with duodenal (-16%) and with gastric ulcer (-27%). The drop in gastric proteolysis after De-Nol is unlikely to be because of the healing of the ulcers and is more likely to be because of the drug. The ulcer healing efficacy of De-Nol may be related to this decline in the proteolytic action of gastric juice, but is unlikely to be because of a quantitative change in mucus, or in acid secretion.     

Mucosal expression and luminal release of epidermal and transforming growth factors in patients with duodenal ulcer before and after eradication of Helicobacter pylori.

BACKGROUND: Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF alpha) are potent gastric acid inhibitors and stimuli of mucosal growth and protection but their involvement in Helicobacter pylori associated duodenal ulcer has been little examined. AIM: To assess gastric acid secretion, plasma gastrin concentrations, mucosal content of EGF and TGF alpha, and mucosal expression of these peptides and their receptor (EGFr) as well as salivary and gastric luminal release of EGF under basal conditions and after pentagastrin stimulation in 10 healthy subjects and in 25 H pylori positive patients with duodenal ulcer before and after two weeks of triple anti-H pylori therapy and four weeks after the termination of this therapy. RESULTS: Pentagastrin stimulation caused a significant increase in salivary and gastric release of EGF both in healthy controls and patients with duodenal ulcers but in the patients, the eradication of H pylori resulted in several fold higher gastric luminal (but not salivary) EGF release than before the anti-H pylori therapy. Mucosal contents of immunoreactive EGF and TGF alpha and mucosal expression of EGF, TGF alpha, and EGFr in H pylori positive patients with duodenal ulcer were significantly higher than those in healthy H pylori negative controls and this increase persisted after eradication of H pylori. Basal plasma gastrin was significantly reduced after two weeks of triple therapy and four weeks after the H pylori eradication all ulcers were completely healed. CONCLUSIONS: (1) H pylori infection in patients with duodenal ulcer was accompanied by enhanced plasma gastrin and increased mucosal content and expression of TGF alpha, EGF, and EGFr; (2) H pylori eradication resulted in ulcer healing, reduction in plasma gastrin, and enhancement of gastric (but not salivary) luminal release of EGF, particularly after pentagastrin stimulation; and (3) enhanced mucosal content and expression of TGF alpha, EGF, and EGFr and increased luminal release of EGF may contribute to ulcer healing after eradication of H pylori.     

Growth of pancreas and gastrointestinal mucosa in antrectomized and gastrin-treated rats.

Growth responses to endogenous and exogenous gastrin were examined in the pancreas and gastrointestinal tract mucosa. Rats were either antrectomized to remove the primary source of endogenous gastrin or subjected to a sham operation. Three weeks after surgery, half of the antrectomized animals were injected ip with pentagastrin (250 microgram/day) four times per day. Injections were carried out for a week. Antrectomy resulted in serum gastrin levels approximately one third of normal. DNA synthesis and DNA and RNA content of the pancreas and oxyntic gland, duodenal, and colonic mucosa were significantly reduced by antrectomy. In each case, pentagastrin treatment restored DNA synthesis and RNA and DNA levels to normal. Significant decreases in pancreatic and colonic weights in antrectomized animals were also completely prevented by pentagastrin injection. These results indicate that endogenous gastrin has an important role in the regulation of pancreatic and colonic mucosal growth, in addition to its already established similar function in oxyntic gland mucosa.     

An experimental study of adrenalin-stimulated gastric acid secretion and gastrin secretion in rats of cysteamine-induced duodenal ulcer]

It is known that cysteamine-induced duodenal ulcers in rats are similar to the human duodenal ulcers in some aspects. We investigated their similarities in view of adrenalin-stimulated gastric acid secretion and gastrin secretion in these rats. Acid outputs decreased in the control group by the administration of adrenaline, but in the cysteamine-administered group acid outputs increased dose dependently. Serum gastrin levels and plasma noradrenaline levels increased by cysteamine administration. The abnormal gastric acid secretion by the adrenalin infusion in the process of cysteamine-induced duodenal ulcers in rats, which was resembled to that of duodenal ulcer patients, was recognized.     

Different HCl and Pepsinogen I Secretion Patterns in Anatomically Defined Gastric Ulcer Subsets

Anatomically, functionally, and clinically, peptic ulcer patients are a heterogeneous group of subjects. These patients can be classified according to the anatomic localization of the niche. The functional state of the gastric mucosa was studied in 30 gastric ulcer patients, 25 duodenal ulcer patients, and 10 normal controls. The classification of the first group was based on Johnson's criteria, with the following results: 10 individuals were type I, 10 were type II, and 10 were type III. Pepsinogen I levels and gastric acid secretion were measured in all 65 subjects under basal conditions and after subcutaneous pentagastrin stimulation. Both basal and stimulated serum pepsinogen I values were significantly higher (p less than 0.05) in gastric ulcer type III patients than in the other four groups. These values in gastric ulcer type I were similar to those of the controls. Gastric ulcer type II patients showed an intermediate functional state similar to that of duodenal ulcer patients. In both gastric ulcer type II and duodenal ulcer patients, the basal and stimulated pepsinogen I levels were significantly higher (p less than 0.05) than those found in controls, whereas the basal serum gastrin levels were similar in the five groups. In conclusion, different HCl and pepsinogen I secretory patterns, with functional heterogenicity of the gastric mucosa, are shown here for the anatomically defined gastric ulcer subsets.     

Efficient treatment of gastric ulcer with proglumide (Milid) in outpatients (double blind trial).

Eleven male and five female gastric ulcer outpatients as well as twenty eight male and seven female duodenal ulcer outpatients received Proglumide (1200 mg/day) or magnesiumtrisilicate (1320 mg/day) in a prospective double blind study. The sizes of the ulcers were assessed by endoscopy before and after 4 weeks therapy. A complete healing of gastric ulcers was observed in 75% (n = 8) of the patients receiving Proglumide and 25% (n = 8) of the antacid treated controls (p less than 0.05; x2 test). The healed area was significantly (p less than 0.05) larger in the Proglumide 91 mm2) than in the anticida group (23 mm2). In addition, the half time of the ulcer-healing was significantly (p less than 0.05) shorter in the Proglumide treated patients (18 days and 26 days respectively). There was no significant effect of the drug on the duodenal ulcers. The spontaneous healing rate was 61% in the antacid (n = 18) and 59% in the Proglumide treated (n = 17) patients. The drug does not effect the basal and pentagastrin stimulated gastric secretion nor the serum gastrin concentration. No side effects on blood pressure, blood cell count, transaminases or blood glucose concentrations could be observed.     

Role of epidermal growth factor in healing of chronic gastroduodenal ulcers in rats

The healing of acetic acid-induced gastric and duodenal ulcers was examined together with biochemical indices of growth in gastric and duodenal mucosa in rats with intact or removed salivary glands after treatment with epidermal growth factor (EGF) or somatostatin, or both. After the extirpation of salivary glands, the healing rate of gastric and duodenal ulcerations was delayed and gastric content of immunoreactive EGF was reduced. This was accompanied by a significant decrease in the contents of deoxyribonucleic acid and ribonucleic acid in the gastric and duodenal mucosa. Repeated administration of EGF either subcutaneously or orally accelerated the healing of gastroduodenal ulcers in rats with intact salivary glands and completely reversed the delay in ulcer healing in sialoadenectomized animals. These effects were also accompanied by a significant increase in the growth parameters of gastric and duodenal mucosa. Administration of somatostatin, which prevented the growth-promoting action of subcutaneous EGF, resulted in a significant decrease in the EGF-stimulated healing of gastric and duodenal ulcerations in both intact and sialoadenectomized rats. Our findings suggest that cell proliferation is an important factor in healing of gastric and duodenal ulcerations and that EGF plays an important role in ulcer healing due to its mitogenic action.     

Natural history and morphology of secretagogue-induced duodenal ulcers in rats.

Morphologically typical ulcers were produced in the first part of the duodenum in 300 male Wistar rats by subcutaneous infusion for 24 hr of pentagastrin (4 mug per kg-min) and carbachol (0.8 mug per kg-min). Groups of animals were killed daily for 14 days, and their stomachs and duodenums were examined. Lesions were graded on a seven-point scale: 0, normal; 1, inflammation; 2, petechiae; 3, erosions; 4, definite ulcer crater; 5, penetrating ulcer; and 6, perforated ulcer. Every animal developed one or more definite ulcers (grades 4 to 6). Within the first 48 hr 34% of the animals died with grade 6 ulcers. Ulcer healing began on the 1st postinfusion day when 3 of 46 rats had erosions (grade 3) but no definite ulcer craters. By the following day some animals were found with normal mucosa. After the 5th postinfusion day the few remaining grade 5 or 6 ulcers were those which had perforated and sealed spontaneously. These long-standing ulcers had several features similar to human chronic duodenal ulcers. By the 12th postinfusion day definite ulcers were no longer seen. In this study duodenal ulcers have not only been produced in rats by secretagogues, but have also been observed to heal. This model can be used to compare the efficacy of various antiulcer regimens on ulcer healing.     

Cigarette smoking, gastric acid secretion, and serum pepsinogen I concentrations in duodenal ulcer patients.

Cigarette smoking has been linked with duodenal ulcer disease although the mechanism of this association is unclear. This study assessed basal gastric secretory response to acute smoking of smokers with an active duodenal ulcer; in addition the possible effects of chronic smoking on gastric secretory capacity, as expressed by pentagastrin stimulated gastric acid secretion and fasting serum pepsinogen I (PG I) concentrations, were investigated in patients with active duodenal ulcer, or non-ulcer dyspepsia. In 10 smokers with duodenal ulcer smoking four cigarettes during 40 minutes did not influence basal gastric secretion of acid and pepsin, or serum PG I and gastrin concentrations. In 136 patients with duodenal ulcer and 90 controls with non-ulcer dyspepsia, pentagastrin stimulated acid secretion and fasting serum PG I concentrations were significantly higher among habitual heavy smokers than among non-smokers. These findings suggest that in heavy smokers with duodenal ulcer acid- and pepsin-secreting cell function is not affected by acute cigarette smoking. By contrast, chronic cigarette smoking seems to be associated either with an increase of parietal- and chief-cell mass, or with an enhancement of their secretory capacity.     

Effect of systemic gastric acid stimulation and intragastric pH changes on synchronous antral gastrin and somatostatin release in anesthetized,nonatropinized duodenal ulcer patients and controls

The synchronous changes in antral gastrin and somatostatin release in anesthetized, nonatropinized duodenal ulcer patients and control subjects were investigated by serial intraoperative blood sampling from the right gastroepiploic vein. The mean basal antral plasma gastrin and somatostatin concentrations of the two groups did not differ significantly. The significantly greater gastric acid secretory response to systemic gastric acid stimulation (pentagastrin stimulation) in duodenal ulcer patients compared with that of control subjects was not linked to any difference in antral somatostatin release pattern. The decrease in antral plasma gastrin release was significantly lower after acid instillation and the increase was significantly higher after alkali instillation in duodenal ulcer patients compared with those of controls, indicating an abnormal gastrin response to intragastric pH changes in duodenal ulcer patients, which was again not found to be coupled to any significant difference in antral somatostatin release. The results suggest that an abnormal somatostatin-mediated inhibition of gastrin release and/or gastric acid secretion does not exist in duodenal ulcer patients.     

胃十二指肠溃疡患者胃窦G细胞的免疫组化观察

用免疫组化方法(PAP)法对胃及十二指肠溃疡患者胃窦粘膜内的胃泌素细胞进行研究,包括计数单位长度粘膜内G细胞密度及观察G细胞内分泌颗粒的数量、着色程度.结果为十二指肠溃疡及胃溃疡患者G细胞密度与对照组无差异.少数十二指肠溃疡患者G细胞密度显著增高,分泌颗粒密集,提示分泌功能亢进.但也有十二指肠质疡患者G细胞密度低于对照组均值者.十二指肠溃疡组内各病例间胃窦G细胞的密度及分泌颗粒数量的差异,支持十二指肠溃疡为多源性疾病的学说.胃溃疡组胃窦G细胞密度与对照组接近,说明其病因主要是胃粘膜保护因素减弱.     

Carcinogenic Action of 2,7-Diacetylaminofluorene on the Stomach of Rats with Experimental Gastric Ulcer

Penetrating ulcers of gastric glandular mucosa were produced in male Buffalo rats by thermocautery. These rats, and uninjured control animals, were fed with a diet containing a known carcinogen, 2,7 diacetylaminofluorene (2,7-DAAF). The purpose of this study was to find whether the presence of gastric ulcer will enhance the incidence of gastric carcinoma. In 14% of rats in which gastric ulcers were associated with the exposure to oral carcinogen, gastric adenocarcinomas were found. No gastric tumors were diagnosed in rats having uninjured gastric mucosas prior to the ingestion of carcinogen. It is concluded that the contact of chemical carcinogen 2,7-DAAF with injured, healing gastric mucosa, enhanced the malignant transformation of gastric cellular elements. Under the conditions of this experiment, the presence of gastric ulcer contributed to the appearance of gastric adenocarcinoma.     

Flow cytometric analysis of cell proliferation kinetics during duodenal ulcer healing

Cell proliferation in the gastroduodenal mucosa of patients with duodenal ulcers was evaluated using flow cytometry. Forty patients with duodenal ulcers and 12 normal subjects were investigated. Biopsy samples were obtained during endoscopic examination and subjected to DNA analysis by flow cytometry. Thirty patients with duodenal ulcers were healed within 3 months with H₂ blockers (tractable or responsive ulcers), whereas 10 patients did not respond to treatment (intractable ulcers). The percentage of cells at the DNA-synthetic phase, an index of cell proliferation, was constant in the adjacent duodenal mucosa 2cm from ulcer margin and antral mucosa during duodenal ulcer healing. The index at the margin of tractable ulcers was elevated during the active stage (12.9 ± 1.3), peaked during the healing stage (15.4 ± 2.8) and returned to the same level at the scarring stage (10.9 ± 2.0) as normal controls (10.3 ± 1.7). However, the index was not elevated in intractable ulcers (10.3 ± 1.7 in the healing stage) and was smaller than in tractable ulcers. These data indicate that augmented mucosal cell proliferation at the ulcer margin plays an important role in duodenal ulcer healing and intractable ulcers are characterized by an abnormal failure to accelerate DNA synthesis to achieve ulcer repair.     

Gastric secretory investigation of recurrent ulcer after surgery for duodenal ulcer.

The results of gastric secretory studies in 192 cases of recurrent ulcer after surgery for duodenal ulcer were analyzed and compared with the secretory data collected in a control group of 74 duodenal ulcer patients who had undergone various forms of gastric surgery, but who did not develop a recurrent ulcer (controls). The patients studied comprised 46 cases of recurrent ulcer after partial gastrectomy, 10 cases of recurrent ulcer after partial gastrectomy and bilateral truncal vagotomy, 56 cases of recurrent ulcer after truncal vagotomy and drainage, 52 cases of recurrent ulcer after highly selective vagotomy, and finally 28 cases in which the recurrent ulcer led to the diagnosis of the Zollinger-Ellison syndrome. The entire study was based upon an analysis of the basal acid output, the response to maximal stimulation by pentagastrin or by histalog and by insulin in the case of previous vagotomy, and finally on an assessment of basal serum gastrin. The analysis has suggested minimal secretory levels with discriminative values useful for the postoperative diagnosis of recurrent ulcer and for an assessment of the completeness of vagotomy (ratio PAO Insulin/PAO pentagastrin or histalog). Moreover, an analysis of various elements of the sequential basal pentagastrin-insulin test permitted us to approach the pathophysiological mechanism responsible for ulcer recurrence, and to identify suitable criteria for selection of the best treatment.     

Zinc deficiency delays gastric ulcer healing in rats

Zinc is an important element in wound healing. Zinc compounds hasten the healing of gastric ulcers, by an unknown mechanism(s). We studied the effect of the induction of zinc deficiency on gastric ulcer healing. Rats were given a control or zinc-deficient diet for six weeks and then subjected to the induction of acetic acid-induced chronic gastric ulcers. Four days later, zinc-deficient rats were divided into two groups. In the first group, the zinc-deficient diet was continued. In the second group, the diet was changed to the control diet. Zinc-deficient rats had a mean serum zinc concentration approximately 70% of that in controls. Zinc deficiency did not affect the formation of gastric ulcers; however, it reduced cell proliferation by day 4 and delayed ulcer healing. Zinc supplementation brought zinc to control levels within a week, but failed to reverse the delay in ulcer healing. We conclude that zinc is crucial for healing of gastric ulcers, especially at the early stage.An abstract of this study was presented at the Second Osaka International Symposium on Gastroenterology held in Osaka, Japan, on November 22–23, 1993.     

Action of omeprazole (a benzimidazole derivative) on secretory responses to sham feeding and pentagastrin and upon serum gastrin and pancreatic polypeptide in duodenal ulcer patients.

The effects of omeprazole, a benzimidazole derivative, have been determined on the secretory responses to modified sham feeding and pentagastrin, and upon serum gastrin and pancreatic polypeptide concentrations in duodenal ulcer patients. Intragastric administration of omeprazole in doses of 2 and 6 mumol/kg produced, respectively, about 50% and 90% reduction in acid outputs in responses to modified sham feeding and pentagastrin without affecting serum gastrin and pancreatic polypeptide response to modified sham feeding.