Omeprazole does not cause unscheduled DNA synthesis in rabbit parietal cells in vitro

Laparoscopic hiatal hernia repair for treating patients with massive hiatal hernia and iron-deficiency anaemia

BACKGROUND

Massive hiatal hernias may result in extraoesophageal symptoms, including iron-deficiency anaemia. However, the role played by hiatal hernias in iron-deficiency anaemia is not clearly understood. We examined the prevalence of anaemia in patients with massive hiatal hernias and the frequency of anaemia resolution after laparoscopic hiatal hernia repair at long term follow-up.

METHODS

Patients who underwent laparoscopic hiatal hernia repair from June 2008 to June 2019 were enrolled in this study. We collected the patients' demographic and clinical data from their medical records, and compared the pre-surgical and post-surgical findings (at 1 week and 3 months post-surgery). All patients with adequate documentation underwent post-surgical follow-up to evaluate improvements in clinical symptoms and signs.

RESULTS

A total of 126 patients with massive hiatal hernias underwent laparoscopic hiatal hernia repair. Of these, 35 (27.8%) had iron-deficiency anaemia. Anaemia was resolution in all the patients and they had significantly reduced GERD-Q scores at 3 months postoperatively (P<0.01) .The mean follow-up period was 60 months. Iron-deficiency anaemia resolution after hiatal hernia repair was achieved in 93.9% of the patients.

CONCLUSION

Anaemia is common in patients with massive hiatal hernias, and most of our patients were symptomatic because of their anaemia. Moreover, in patients with massive hiatal hernias, iron-deficiency anaemia resolution is likely after laparoscopic hiatal hernia repair.

Pharmacological Effects and Toxicogenetic Impacts of Omeprazole: Genomic Instability and Cancer

Omeprazole (OME) is commonly used to treat gastrointestinal disorders. However, long-term use of OME can increase the risk of gastric cancer. We aimed to characterize the pharmacological effects of OME and to correlate its adverse effects and toxicogenetic risks to the genomic instability mechanisms and cancer-based on database reports. Thus, a search (till Aug 2019) was made in the PubMed, Scopus, and ScienceDirect with relevant keywords. Based on the study objective, we included 80 clinical reports, forty-six in vitro, and 76 in vivo studies. While controversial, the findings suggest that long-term use of OME (5 to 40 mg/kg) can induce genomic instability. On the other hand, OME-mediated protective effects are well reported and related to proton pump blockade and anti-inflammatory activity through an increase in gastric flow, anti-inflammatory markers (COX-2 and interleukins) and antiapoptotic markers (caspases and BCL-2), glycoprotein expression, and neutrophil infiltration reduction. The reported adverse and toxic effects, especially in clinical studies, were atrophic gastritis, cobalamin deficiencies, homeostasis disorders, polyp development, hepatotoxicity, cytotoxicity, and genotoxicity. This study highlights that OME may induce genomic instability and increase the risk of certain types of cancer. Therefore, adequate precautions should be taken, especially in its long-term therapeutic strategies and self-medication practices.

Gastrin has a specific proliferative effect on the rat enterochromaffin-like cell, but not on the parietal cell: a study by elutriation centrifugation

Gastrin has a general growth-promoting effect on gastric oxyntic mucosa, and a more pronounced one on the enterochromaffin-like (ECL) cell. Whether gastrin has a proliferative effect on the parietal cell lineage beyond the general effect is uncertain. Hypergastrinaemia was evoked in rats using pantoprazole (group II: 100 micromol kg-1, group III: 400 micromol kg-1) for 45 days. Plasma gastrin was 43 +/- 8 pmol L-1 (control), 283 +/- 54 pmol L-1 (group II) and 577 +/- 63 pmol L-1 (group III). Gastric mucosal cells were isolated and fractionated by elutriation centrifugation. Total cell number, percentage and number of ECL and parietal cells, and histamine were determined in each fraction. The number of mucosal cells increased 1.5-fold in both hypergastrinaemic groups. Enterochromaffin-like cell content was 2.6 +/- 0.5% (control), 6.0 +/- 0.6% (group II) and 9.0 +/- 0.8% (group III). Histamine concentration in oxyntic mucosal cells rose similarly. The size of the ECL cells was 8.5 +/- 0.1 microm (control), 10.8 +/- 0.2 microm (group II) and 12.1 +/- 0.2 microm (group III), and the increased size was confirmed by shifted distribution in elutriation fractions. Histamine per ECL cell increased with cell size. The number of parietal cells increased parallel to the total number of mucosal cells (1.5-fold). Parietal cell size and percentage, assessed by image analysis and distribution in elutriation fractions, were unchanged after pantoprazole dosing. Gastrin has a pronounced, concentration-dependent specific trophic effect on ECL cells and a general proliferative effect on gastric mucosa, including parietal cells.

Co-purification of gastric mucoproteins with DNA: an explanation for the reported 'interaction' of omeprazole with DNA in rat tissues

Recently, Phillips et al. reported that small amounts of radioactivity derived from [14C]omeprazole were 'associated' with DNA purified from gastrointestinal tissues of treated rats (Mutagenesis 7, 277-283, 1992). We hypothesized that this radioactivity arose from omeprazole bound to contaminating protein in the DNA fraction (Mutagenesis 7, 395-396, 1992). Using rats injected with 35S-labeled amino acids, we found significant protein contamination (0.06 microgram of protein per microgram of DNA) in DNA purified from gastrointestinal tissues. Gastric mucous proteins represent likely candidates for binding of omeprazole in the rat model used by Phillips et al. To investigate this, we partially purified proteins from gastric mucus, incubated them with [14C]omeprazole, and then added these radiolabeled mucoproteins to homogenates of rat colon and duodenum before starting the DNA purification. Detectable amounts of the added mucoproteins remained in the DNA fraction, but none of the control protein, bovine serum albumin, remained with the DNA. Further characterization of the mucoproteins by hydroxyapatite chromatography indicated that a certain population of these proteins survived the DNA purification procedures. These data indicate that the association of omeprazole with DNA reported by Phillips et al. most probably is explained by binding of omeprazole to mucous glycoproteins (or other proteins present in the GI tract) that selectively survive DNA purification protocols.

Pharmacology of gastric acid inhibition

Gastric acid secretion is precisely regulated by neural (acetylcholine), hormonal (gastrin), and paracrine (histamine; somatostatin) mechanisms. The stimulatory effect of acetylcholine and gastrin is mediated via increase in cytosolic calcium, whereas that of histamine is mediated via activation of adenylate cyclase and generation of cAMP. Potentiation between histamine and either gastrin or acetylcholine may reflect postreceptor interaction between the distinct pathways and/or the ability of gastrin and acetylcholine to release histamine from mucosal ECL cells. The prime inhibitor of acid secretion is somatostatin. Its inhibitory paracrine effect is mediated predominantly by receptors coupled via guanine nucleotide binding proteins to inhibition of adenylate cyclase activity. All the pathways converge on and modulate the activity of the luminal enzyme, H+,K(+)-ATPase, the proton pump of the parietal cell. Precise information on the mechanisms involved in gastric acid secretion and the identification of specific receptor subtypes has led to the development of potent drugs capable of inhibiting acid secretion. These include competitive antagonists that interact with stimulatory receptors (e.g. muscarinic M1-receptor antagonists and histamine H2-receptor antagonists) as well as non-competitive inhibitors of H+,K(+)-ATPase (e.g. omeprazole). The histamine H2-receptor antagonists (cimetidine, ranitidine, famotidine, nizatidine and roxatidine acetate) continue as first-line therapy for peptic ulcer disease and are effective in preventing relapse. Although they are generally well tolerated, histamine H2-receptor antagonists may cause untoward CNS, cardiac and endocrine effects, as well as interfering with the absorption, metabolism and elimination of various drugs. The dominance of the histamine H2-receptor antagonists is now being challenged by omeprazole. Omeprazole reaches the parietal cell via the bloodstream, diffuses through the cytoplasm and becomes activated and trapped as a sulfenamide in the acidic canaliculus of the parietal cell. Here, it covalently binds to H+,K(+)-ATPase, the hydrogen pump of the parietal cell, thereby irreversibly blocking acid secretion in response to all modes of stimulation. The main potential drawback to its use is its extreme potency which sometimes leads to virtual anacidity, gastrin cell hyperplasia, hypergastrinaemia and, in rats, to the development of carcinoid tumours. The cholinergic receptor on the parietal cell has recently been identified as an M3 subtype and that on postganglionic intramural neurones of the submucosal plexus as an M1 subtype.(ABSTRACT TRUNCATED AT 400 WORDS)