Oxidative and phosphorylative activities of the gastric mucosa of animals and humans in relation to the mechanism of stress ulcer

Association between fibromyalgia syndrome and peptic ulcer disease development

PURPOSE

The correlation of fibromyalgia syndrome (FMS) with peptic ulcer disease (PUD) is unclear. We therefore conducted a cohort study to investigate whether FMS is correlated with an increased risk of PUD.

METHODS

In this study, we established an FMS cohort comprising 26068 patients aged more than 20 years who were diagnosed with FMS from 2000 to 2011. Furthermore, we established a control cohort by randomly choosing 104269 people without FMS who were matched to the FMS patients by gender, age, and index year. All patients were free of PUD at the baseline. Cox proportional hazard regressions were performed to compute the hazard ratio of PUD after adjustment for demographic characteristics and comorbidities.

RESULTS

The prevalence of comorbidities was significantly higher in the FMS patients than in the controls. The incidence of PUD was 29.8 and 19.4 per 1000 person-years in the FMS and control cohorts, respectively. In addition, the FMS cohort exhibited a 1.40-fold higher risk of PUD (95% confidence interval = 1.35-1.45) compared with the control cohort. After control for confounding factors, the medications (selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and antidepressants) taken by the FMS patients did not increase the risk of PUD.

CONCLUSION

FMS patients exhibit a higher risk of PUD than that of patients without FMS.

Atrophic gastritis: deficient complex I of the respiratory chain in the mitochondria of corpus mucosal cells

BACKGROUND

Mitochondrial dysfunction is one of the most characteristic properties of the cancer cell. However, it is not known whether oxidative energy metabolism has already become altered in conditions of atrophic gastritis, a precancerous state of gastric disease. The purpose of our study was to comparatively characterize oxidative phosphorylation (OXPHOS) in the atrophic and nonatrophic gastric corpus mucosa.

METHODS

Mucosal biopsies were taken from 12 patients with corpus dominant atrophic gastritis and from 12 patients with nonatrophic mucosa (controls). One part of the tissue samples was permeabilized with saponin for analysis of the function of the respiratory chain using high-resolution respirometry, and another part was used for histopathological examination. The serum level of pepsinogen I (S-PGI) was determined with a specific enzyme immunoassay (EIA).

RESULTS

Compared to the control group, the maximal capacity of OXPHOS in the atrophy group was almost twofold lower, the respiratory chain complex I-dependent respiration, normalized to complex II-dependent respiration, was reduced, and respiratory control by ADP in the presence of succinate was increased in the atrophic corpus mucosa. In the whole cohort of the patients studied, serum S-PGI level correlated positively with complex I-dependent respiration or complex I-dependent to complex II-dependent respiration ratio.

CONCLUSIONS

Corpus dominant atrophic gastritis is characterized by decreased respiratory capacity and relative deficiency of the respiratory complex I of mitochondria in the mucosa, the latter defect probably limiting mitochondrial ATP production and energetic support of the secretory function of the zymogenic mucosal cells.

Oxidative phosphorylation and its coupling to mitochondrial creatine and adenylate kinases in human gastric mucosa

Energy metabolism in gastrobiopsy specimens of the antral and corpus mucosa, treated with saponin to permeabilize the cells, was studied in patients with gastric diseases. The results show twice lower oxidative capacity in the antral mucosa than in the corpus mucosa and the relative deficiency of antral mitochondria in complex I. The mucosal cells expressed mitochondrial and cytosolic isoforms of creatine kinase and adenylate kinase (AK). Creatine (20 mM) and AMP (2 mM) markedly stimulated mitochondrial respiration in the presence of submaximal ADP or ATP concentrations, and creatine reduced apparent Km for ADP in stimulation of respiration, which indicates the functional coupling of mitochondrial kinases to oxidative phosphorylation. Addition of exogenous cytochrome c increased ADP-dependent respiration, and the large-scale cytochrome c effect (>or=20%) was associated with suppressed stimulation of respiration by creatine and AMP in the mucosal preparations. These results point to the impaired mitochondrial outer membrane, probably attributed to the pathogenic effects of Helicobacter pylori. Compared with the corpus mucosa, the antral mucosa exhibited greater sensitivity to such type of injury as the prevalence of the large-scale cytochrome c effect was twice higher among the latter specimens. Active chronic gastritis was associated with decreased respiratory capacity of the corpus mucosa but with its increase in the antral mucosa. In conclusion, human gastric mucosal cells express the mitochondrial and cytosolic isoforms of CK and AK participating in intracellular energy transfer systems. Gastric mucosa disease is associated with the altered functions of these systems and oxidative phosphorylation.

A method for the estimation of the hemoglobin distribution in gastroscopic images

The assessment of blood flow in the gastrointestinal mucosa could be a useful indicator for the diagnosis and treatment of several diseases, such as ulcers, gastritis, colitis or early cancer. The quantity of blood flow is roughly estimated by computing the spatial hemoglobin distribution in the mucosa. The method presented here enables a practical realization by calculating approximately the hemoglobin concentration based on a spectrophotometric analysis of endoscopic true-color images, which are recorded during routine examinations. A system model based on the reflectance spectroscopic law of Kubelka-Munk is derived, which enables an estimation of the hemoglobin concentration by means of the color values of the images. Additionally, a transformation of the color values is developed, in order to improve the luminance independence. Applying this transformation and estimating the hemoglobin concentration for each pixel of interest, the hemoglobin distribution can be computed. The results obtained are mostly independent of luminance. An initial validation of the method is made by a quantitative estimation of the reproducibility.

NSAIDS and the microcirculation of the stomach

In this article, the effect of NSAIDs on the gastric mucosal microcirculation was reported. Although the precise mechanism of NSAID-induced ulcerogenesis is still unknown, most NSAIDs have been shown to impair gastric mucosal microcirculation and cause gastric mucosal damage.

Age-related change in human gastric mucosal energy metabolism

Many investigators have reported a decrease in mucosal blood flow resulting in impairment of gastric mucosal energy metabolism in animal experiments. Recently, endoscopic studies using reflectance spectrophotometry and laser Doppler flowmetry have indicated that gastric mucosal blood flow in humans decreases with age. However, changes in energy metabolism in human gastric mucosa with age remains obscure. In this study, we measured adenine nucleotides in biopsy samples from human gastric mucosa, using high-performance liquid chromatography, and investigated changes in energy metabolism with age in subjects proven normal endoscopically. Energy charge (EC = (ATP + 1/2 ADP)/ATP + ADP + AMP) in the gastric antral and body mucosa showed decrease with age. When the subjects were divided into two groups, less than and more than 65 years old, the EC level was significantly lower in the latter than the former in both antral and body mucosa (0.65 +/- 0.06 versus 0.74 +/- 0.03 in the antrum, 0.73 +/- 0.04 versus 0.79 +/- 0.04 in the body) and significantly less in the antral mucosa than in body mucosa in both groups. The adenosine triphosphate (ATP) level in the older group showed a significant decrease (6.48 +/- 1.14 versus 9.63 +/- 1.92 in the antrum, 8.59 +/- 1.64 versus 10.60 +/- 2.13 in the body) compared with those less than 65 years old. In the antral mucosa of the older group the adenosine diphosphate (ADP) level was also significantly lower than that in the group less than 65. In conclusion, in the elderly, the energy metabolism in human gastric mucosa is impaired, and this may weaken their defensive mechanism.

Isolation and characterization of human and canine gastric mucosal glycoproteins and their degradation by proteases and acid hydrolases

High molecular weight glycoproteins were isolated and purified from canine antral and fundic mucosal tissue by means of non-degrading techniques. The results disclosed the advantage of urea extraction technique over the culture method in isolating the native glycoproteins. The glycoproteins were susceptible to degradation by protease, thus yielding low molecular weight glycopeptides. Chemical analysis of these glycopeptides and their parent macromolecules revealed that the oligosaccharide residues are attached to threonine, serine and proline residues of the protein chains. Similarly, high molecular weight glycoproteins isolated from human gastric gel mucin showed the same characteristics of canine gastric glycoproteins. Canine fundic glycoprotein or glycopeptide released their prosthetic carbohydrate groups under the lytic effect of fundic acid hydrolases.

Urate metabolism and gastric ulcerations in rats as influenced by stress and allopurinol

Stress and allopurinol (ALL) were investigated in rats with regard to their influence on serum uric acid and glucose concentration, gastric secretion, microcirculation (MBF) and stress ulcer index. There is a non-competitive type of interaction between severe stress and ALL-mediated xanthine oxydase inhibition (= per cent fall in serum uric acid) as compared with control conditions (= mild stress). Vmax is different (84.6 +/- 1.9 and 92.3+/-2.26; P less than 0.05), but not Km (0.39 +/- 0.09 and 0.68 +/- 0.08 mg/kg/h ALL). Serum uric acid is higher in rats with draining gastric fistula than those with closed fistula suggesting that already mild stress is associated with an increase in uricemia in this species. ALL does not significantly alter gastric acid and uric acid secretion but improves markedly gastric ulcer index during mild and severe stress. Since MBF is significantly elevated by ALL during the latter circumstances, a dissociation between MBF and acid secretion is one feature of ALL actions and might become a primary aim in treatment of this disorder.