L. Lundell

Osteoporosis after total gastrectomy : Results of a prospective, clinical study

BACKGROUND Osteopenia and enhanced risk of fractures have been reported after partial gastrectomy, but the significance of total gastrectomy is still unknown. METHODS Twenty-six patients were followed up for at least 3 years after total gastrectomy. The intake and S-levels of vitamin D, phosphate, magnesium, and calcium were prospectively studied, and a whole-body dual-energy X-ray absorptiometry scan was performed at a mean of 5 years after gastrectomy. RESULTS At this time point we found normal blood levels of vitamin D, calcium, and phosphate. Food intakes of phosphate, calcium, magnesium, and vitamin D reached the recommended daily allowances. Bone mineral density was similar to that of a control population, and increasing values were seen concomitant with an increase in body weight with the time after gastrectomy. CONCLUSIONS Calcium homeostasis and bone mineral densities seem not to be affected by total gastrectomy, at least when studied over a period of 5 years, an observation that hypothetically can be explained by weight recovery with time after the operation.

Effects of Partial Resection of Acid-Secreting Mucosa on Plasma Gastrin and Enterochromaffin-Like Cells in the Rat Stomach

Female rats were subjected to various degrees (50, 75, 90 and 100%) of fundectomy, i.e. resection of the acid-producing part of the stomach, to compare the effects of different degrees of reduction of the amount of acid reaching the antrum. Plasma gastrin was monitored for 10 weeks after the operation. Histidine decarboxylase (HDC) activity, histamine concentration and density of enterochromaffin-like (ECL) cells in the remaining oxyntic mucosa were determined in the rats subjected to 50 or 75% fundectomy. There was a close correlation between the amount of acid-producing mucosa removed and the plasma gastrin levels, the highest gastrin level being observed in the rats subjected to 100% fundectomy. HDC activity, histamine concentration and ECL cell density seemed to reflect plasma gastrin concentration. These findings indicate that hypergastrinemia induced by surgical removal of acid-producing mucosa in the rat has the same effects on oxyntical mucosal HDC activity, histamine concentration and ECL cell density as hypergastrinemia induced by continuous gastrin infusion or by long-term treatment with effective antisecretagogues.

Acid Suppression in the Long-Term Treatment of Peptic Stricture and Barrett’s Oesophagus

Peptic stricture and Barretts oesophagus are not only the major, but also the most common, complications of gastro-oesophageal reflux disease. The clinical problems that these manifestations present are highly significant, and in patients with peptic stricture the resultant dysphagia can be a major disability that causes nutritional problems. Dilation of a stricture exposes the patient to a small, but significant, risk of oesophageal perforation. Barretts oesophagus per se rarely causes morbidity, but carries a significant risk of developing oesophageal carcinoma, with its attendant morbidity and mortality. Successful anti-reflux surgery for peptic stricture and Barretts oesophagus effectively abolishes pathological oesophageal acid exposure and provides the best indicator of the potential benefits that may be obtained from treatment with acid-inhibitory drugs. The reported experience clearly indicates that successful anti-reflux surgery results in resolution of peptic stricture following initial dilation, concomitant with persistent control of oesophageal acid exposure. In patients with Barretts oesophagus, healing of oesophagitis is well documented after successful surgery, but it is unclear whether the Barretts epithelium progresses or regresses significantly in all but a minority of patients. It is now established that acid pump inhibition can reduce pathological oesophageal acid exposure as effectively as successful anti-reflux surgery. In a minority of patients, however, omeprazole, 40 or 60 mg daily, divided into two doses, is necessary to achieve this effect. This is particularly true for patients with the more severe forms of disease, in whom peptic stricture and Barretts oesophagus are most prevalent. Results indicate that peptic stricture can resolve during effective gastric acid inhibition with omeprazole, and results from controlled trials on the management of these patients with omeprazole are awaited. Similarly, there are reports of regression of Barretts oesophagus during omeprazole therapy, but the completeness and predictability of any such effect have not yet been adequately evaluated. There is sufficient experience from long-term omeprazole treatment of gastro-oesophageal reflux disease to indicate that maintenance of a satisfactory response of peptic stricture or Barretts oesophagus depends upon continued effective gastric acid inhibition.

Gastrin-releasing peptide: neuronal distribution and spatial relation to endocrine cells in the human upper gut

By using immunocytochemical techniques, we have studied the distribution of gastrin releasing peptide (GRP)-containing neurons as well as the spatial relationship between these neurons and the endocrine cells in the human stomach and duodenum. Moderate numbers of immunoreactive fibers were distributed in the smooth muscle and submucosa of the stomach; they were more rare in the duodenal wall. Numerous GRP-containing nerve fibers were found in the oxyntic mucosa, the antral mucosa harboured only few GRP immunoreactive nerve fibers. The mucosa of the proximal duodenum was found to be virtually devoid of such fibers. Only occasionally did we observe signs of a direct contact between GRP-containing nerve fibers and gastrin and somatostatin cells in the antral mucosa. In the oxyntic mucosa GRP-containing nerve fibers sometimes seemed to contact endocrine cells, including somatostatin cells as well as individual parietal cells. In conclusion, although GRP-containing nerve fibers were quite numerous in the wall of the human upper gastro-intestinal (GI)-tract, we observed a lack of intimate spatial relationship between these fibers and endocrine cells in the antral mucosa, suggesting additive mechanisms to a direct innervation of gastrin cells and somatostatin cells by GRP nerve fibers explaining the physiological effects on hormonal release.

Effect of Parietal Cell Vagotomy and Cholinergic Blockade on Gastrin Release in Man Induced by Gastrin-Releasing Peptide

The influence of cholinergic blockade as well as vagal denervation of the oxyntic gland mucosa on the gastrin response to gastrin-releasing peptide (GRP) have been studied in patients with duodenal ulcer disease. The gastric luminal content was neutralized during the experiments. GRP induced a substantial increase in gastrin levels with a peak response already after 15 min of infusion. Vagal denervation of the parietal cell area induced a significant increase in basal gastrin concentrations and a significant enhancement of the GRP response. Two different doses of benzilonium bromide were studied and neither influenced the basal concentrations of gastrin. A significantly increased gastrin response to GRP was, however, observed after administration of both a high and a very low dose of the anticholinergic drug. Our results delineate a vagal, noncholinergic inhibitory influence on the basal gastrin release. In addition a vagally dependent oxyntopyloric mechanism inhibits the gastrin release stimulated by GRP. This inhibitory mechanism may hypothetically be a cholinergic reflex mechanism.

Treatment of Devastating Postgastrectomy Symptoms: The Potential Role of Jejunal Pouch Reconstruction

After gastrectomy a few patients develop severe symptoms and malnutrition. There are probably several reasons for this, such as insufficient gastric reservoir function, malassimilation, diarrhea and dumping. The patient presented here developed severe malnutrition after partial gastrectomy and his weight gradually decreased from 95 to 40 kg during the first 6 postoperative years. His major complaint was postprandial vomiting and early satiety. During the course of his illness, he was repeatedly investigated with computerized tomography scans, repeated endoscopies with biopsies, barium examinations, etc. Finally the only positive finding was bacterial intestinal overgrowth, but antibiotic treatment did not improve his condition. After repeated periods of parenteral nutrition or enteral tube feeding, an S-shaped jejunal pouch was attached to the gastric remnant. Dual-energy X-ray absorptiometry was used to examine the body composition and bone density in the immediate postoperative period and 1 year after the operation. During the first postoperative year he gained 11 kg weight and reported an essentially normal food intake. Both laboratory and clinical parameters improved and a gain in lean body mass was recorded. Patients with severe postgastrectomy symptoms, with no other plausible explanation than nonexistent or insufficient gastric reservoir function, may benefit from re-reconstruction with a jejunal pouch.

Effects of Some Gastrointestinal Peptides on Isolated Human and Rabbit Gastric Glands

The isolated gastric gland preparation, with aminopyrine accumulation as an index of the parietal cell response, has been used to study the effects of somatostatin (S-14), gastrin-releasing peptide (GRP), cholecystokinin (CCK-8), vasoactive intestinal peptide (VIP), and peptide YY (PYY) on the in vitro acid secretion in human and rabbit oxyntic mucosa. Somatostatin was able to inhibit the parietal cell response to histamine in both human and rabbit isolated gastric glands (maximal inhibition, 22% and 34%, respectively) but failed to inhibit the parietal cell response to db-cAMP. However, other peptides capable of inhibiting gastric acid secretion in vivo, such as CCK, VIP, and PYY, were unable to induce any inhibition of the parietal cell response to db-cAMP or histamine in the isolated gastric gland preparation irrespective of the species studied. GRP was not able to induce a parietal cell response, a finding that is in accord with the assumption that the stimulatory effect of GRP on gastric acid secretion in vivo is by releasing gastrin from antral G-cells.

Defective Inhibition of Gastrin Release by Antral Distension in Duodenal Ulcer Patients

The gastrin response to a low and a high dose of gastrin-releasing peptide infusion was studied in healthy volunteers and in patients with duodenal ulcer disease. In duodenal ulcer patients, the gastrin response was exaggerated. Cholinergic blockade did not change the gastrin release in healthy volunteers. Antrum distension during neutralization of the gastric lumen was unable to stimulate gastrin release, also under cholinergic blockade. However, in healthy volunteers distension of the antrum significantly inhibited the gastrin response to gastrin-releasing peptide infusion. This inhibitory influence was most pronounced in patients given the lower dose of the neuropeptide. Cholinergic blockade counteracted the inhibitory effect exerted by antral distension. On the other hand, antral distension did not alter the gastrin response to gastrin-releasing peptide in patients with duodenal ulcer disease. These results suggest an additional defective inhibitory mechanism in duodenal ulcer patients.

Gastrin and somatostatin in the rat antrum. The effect of removal of acid-secreting mucosa

Female rats were subjected to operations aimed at reducing the amount of oxyntic gland mucosa draining its acid secretion to the antrum. The rats were provided either with Heidenhain or Pavlov pouches reducing the oxyntic mucosa draining its secretion to the antrum by about 50% or subjected to various degrees (75, 90 and 100%) of fundectomy. Ten weeks following surgery, plasma levels of gastrin and somatostatin were assayed. At the same time, antral mucosal content of gastrin and somatostatin was determined as well as the mucosal density of these hormone-producing cells. There was a relationship between the amount of acid-secreting mucosa removed and the ensuring plasma concentration of gastrin. Thus, a stepwise increase in plasma gastrin was found with the highest levels obtained in rats subjected to 90 or 100% fundectomy. The somatostatin concentration in plasma was reduced only in rats subjected to fundectomy with the most sustained decrease in animals in which all oxyntic gland mucosa had been removed. There was also a relationship between the amount of acid-secreting mucosa removed and the gastrin content of the antral mucosa. An inverse relationship seemed to exist between antral gastrin and somatostatin concentrations. However, a significant decrease in somatostatin concentration of the antral mucosa was seen only in rats subjected to a fundectomy. The number of gastrin cells in the antral mucosa was increased in fundectomized rats only, with the largest density seen in rats deprived of all oxyntic mucosa. A corresponding decrease in the number of somatostatin cells was noticed. Our results would suggest an apparent functional relationship between antral gastrin and somatostatin cells, where the antral acid load (or pH) appears to be the major factor of physiological significance.

Factors Influencing the Release of Cholecystokinin Induced by Gastrin-Releasing Peptide in Man

We have studied the basal release of cholecystokinin (CCK) and the CCK response to gastrin-releasing peptide (GRP) in man. GRP infusion was followed by a substantial and immediate release of CCK. Pancreatico-duodenectomy or antrectomy with or without duodenal exclusion or antrectomy with truncal vagotomy did not significantly change the basal release of CCK or the GRP-induced CCK release. These results indicate that both basal and GRP-induced release of CCK predominantly originate from the small intestine below the duodenum and the upper part of the jejunum and is unchanged by duodenal exclusion and vagal denervation of the small intestine.