Influence of age and gender on gastric acid secretion as estimated by integrated acidity in patients referred for 24-hour ambulatory pH monitoring

Impact of aging on the digestive system related to protein digestion in vivo

For the current aging population, protein is an important macronutrient to counteract the development of sarcopenia. Protein digestion is influenced by the capacity of the digestive system. The current evidence is reviewed about the impact of aging on the human digestive system and related to protein digestion in vivo. Aging changes the digestive organs which impacts protein digestion. Dentition decreases and mastication changes, potentially affecting particle size reduction. Stomach gastric acidity is unchanged, gastric emptying is delayed, while total transit time remains unchanged. Production of enzymes by the pancreas is decreased, but any changes in the small intestine remain unresolved. Animal studies showed decreased fecal protein digestion in older compared to young animals. Human studies showed decreased postprandial peripheral plasma appearance of ingested amino acids and increased splanchnic extraction. The findings suggest that the deteriorating digestive system with aging results in decreased protein digestion. Interpretation of the results should be taken with caution because of interindividual differences in the aging process, and because studies on protein digestion in aging humans are scarce. More information is needed on healthy aging and its relation to the digestive tract and protein digestion, several methods including in vitro experiments are valuable in this perspective.

Amorphous Solid Dispersion Tablets Overcome Acalabrutinib pH Effect in Dogs

Calquence^® (crystalline acalabrutinib), a commercially marketed tyrosine kinase inhibitor (TKI), exhibits significantly reduced oral exposure when taken with acid-reducing agents (ARAs) due to the low solubility of the weakly basic drug at elevated gastric pH. These drug-drug interactions (DDIs) negatively impact patient treatment and quality of life due to the strict dosing regimens required. In this study, reduced plasma drug exposure at high gastric pH was overcome using a spray-dried amorphous solid dispersion (ASD) comprising 50% acalabrutinib and 50% hydroxypropyl methylcellulose acetate succinate (HPMCAS, H grade) formulated as an immediate-release (IR) tablet. ASD tablets achieved similar area under the plasma drug concentration-time curve (AUC) at low and high gastric pH and outperformed Calquence capsules 2.4-fold at high gastric pH in beagle dogs. In vitro multicompartment dissolution testing conducted a priori to the in vivo study successfully predicted the improved formulation performance. In addition, ASD tablets were 60% smaller than Calquence capsules and demonstrated good laboratory-scale manufacturability, physical stability, and chemical stability. ASD dosage forms are attractive for improving patient compliance and the efficacy of acalabrutinib and other weakly basic drugs that have pH-dependent absorption.

Bacterial colonization of the stomach and duodenum in a Swedish population with and without proton pump inhibitor treatment

Background and Aim

Microbial contamination of the abdominal cavity is a serious concern during transgastric endoscopic interventions and perforations, particularly in patients who have inhibited gastric acid secretion due to treatment with proton pump inhibitors (PPIs).

The aim of this study was to investigate the gastric and duodenal bacterial flora in patients with and without PPI treatment.

Methods

Patients referred for gastroscopy, without recent antibiotic treatment, were eligible for inclusion. Use of PPIs was recorded. Samples for bacterial culturing were obtained from the antrum of the stomach and from the duodenal bulb through a gastroscope. Positive cultures were examined for bacterial types and subtypes. Biopsies were taken in the antrum for urease test to detect Helicobacter pylori.

Results

Bacterial cultures from the stomach were obtained from 103 patients, and duodenal samples were also cultured from 49 of them, for a total of 53 patients with PPI use and 50 patients without. Positive gastric cultures were found in 42 of 53 patients with PPI use and in 13 of 50 without (P < 0.0001). Duodenal cultures were positive in 20 of 24 with PPI and 8 of 25 without (P < 0.0001). The most commonly identified bacterial species were oral strains of Streptococcus, followed by Neisseria and Haemophilus influenzae. Of 103 patients, 10 had a positive urease test, indicating H. pylori infection, 1 with PPI and 9 without.

Conclusions

Bacterial growth in the stomach and duodenum is more common in patients with PPI treatment. The dominating bacterial species found in the stomach and duodenum originates from the oropharynx.

Clinical trials registry: Trial registration number 98041 in Researchweb (FoU in Sweden).

EFFECT OF AGE AND GENDER ON FASTING AND FOOD-STIMULATED LEVELS OF CALCITONIN, PARATHYROID, AND GASTRIN HORMONES IN HEALTHY ADULTS

Objective: To investigate the effect of age and gender on basal and food-stimulated serum calcitonin (CT), parathyroid hormone (PTH), and gastrin levels among healthy adults. Methods: Ninety-six healthy adults (76 men and 20 women) aged between 21 and 43 years were recruited. Serum CT, PTH, and gastrin levels were measured after a 9-hour overnight fast, and 1 and 3 hours postprandially. Results: PTH levels decreased early and increased late after feeding. This change was significant in men but not in women. CT levels increased in response to food intake in men but not in women. Gastrin levels were significantly increased after feeding in both men and women. Mean basal and food stimulated CT, PTH, and gastrin levels did not significantly differ between genders. Fasting and post-prandial PTH levels were higher while gastrin levels were lower in older subjects (>30 years old) compared to younger subjects (≤30 years old). Fasting and postprandial CT levels were not significantly different between age groups. Conclusion: Age had a significant effect on fasting and food-stimulated PTH and gastrin hormone levels. The effect of age on PTH levels was independent of baseline vitamin D levels. Men showed significant changes in CT and PTH levels in response to feeding compared to women, although the mean hormone levels were not significantly different between men and women. Abbreviations: CT = calcitonin; MTC = medullary thyroid carcinoma; PTH = parathyroid hormone; SD = standard deviation.

Hypergastrinemia in Long-Term Use of Proton Pump Inhibitors

BACKGROUND/AIM

The use of proton pump inhibitors (PPIs) is known to lead to hypergastrinemia; however, the data in patients with atrophic gastritis is still lacking. The aim of this study was to investigate the effects of long-term PPIs use on the gastrin levels in patients with atrophic gastritis and to determine factors affecting hypergastrinemia in long-term users of PPIs.

METHODS

Serum Helicobacter pylori IgG, gastrin and pepsinogen levels were measured. Atrophic gastritis was assessed by upper gastrointestinal endoscopies based on the Kimura-Takemoto classification and pepsinogen levels. CYP2C19 polymorphisms were assessed using DNA extracted from peripheral blood.

RESULTS

A total number of 382 patients (275 men and 107 women) were enrolled. Median serum gastrin levels were higher in PPI users than in non- users (234 vs. 113 pg/mL, p < 0.001) and in women than in men (252 vs. 155 pg/mL, p = 0.006). Gastrin levels were significantly associated with corpus atrophy only in the subgroup of non-users of PPIs. Multivariate analysis revealed that hypergastrinemia (over 150 pg/mL) was significantly associated with PPI use (OR 5.30; 95% CI 3.32-8.47), women (OR 2.22; 95% CI 1.33-3.72) and corpus atrophy (OR 1.82; 95% CI 1.14-2.90).

CONCLUSION

PPI use, women and corpus atrophy were risk factors for hypergastrinemia. Gender, but not corpus atrophy, affected the gastrin levels in long-term users of PPIs.

24-Hour Measurement of Gastric pH in Rural South Africa

Background. Previous studies have established norms of 24-hour gastric pH profiles for western countries. This study was designed to establish the pattern for a rural African population with a high incidence of oesophageal cancer. Methods. After lower oesophageal manometry a probe was placed 10 cm distal to the lower oesophageal sphincter. We carried out 24-hour ambulatory monitoring of gastric pH on 59 healthy subjects. This was satisfactorily completed on 26 female and 18 male (age 21–64, median 35) subjects in the Transkei region of South Africa. Results. The mean 24 hour gastric pH was 2.84 and the mean night-time pH was 3.7. 40 volunteers recorded a night-time pH reaching over 4. 33 volunteers recorded a night-time pH over 7. Night-time alkalinisation was present for 136.4 minutes (25th centile 22.8, 75th centile 208.1) at pH4 or over, and 79.3 (2.5, 122.7) minutes at pH7 or over. Episodes of rapid alkaline rise were 17 (10, 47). 21.1% of these occurred while supine. 35 of 36 tested subjects were positive for H. pylori IgG. Conclusion. Gastric alkalinisation is common in Transkei, at a higher pH than that reported in other studies, and is sustained longer. Nighttime alkalinisation is frequent. This suggests a high level of duodenogastric reflux.

A plausible explanation for male dominance in typhoid ileal perforation

The phenomenon of consistent male dominance in typhoid ileal perforation (TIP) is not well understood. It cannot be explained on the basis of microbial virulence, Peyer’s patch anatomy, ileal wall thickness, gastric acidity, host genetic factors, or sex-linked bias in hospital attendance. The cytokine response to an intestinal infection in males is predominantly proinflammatory as compared with that in females, presumably due to differences in the sex hormonal milieu. Sex hormone receptors have been detected on lymphocytes and macrophages, including on Peyer’s patches, inflammation of which (probably similar to the Shwartzman reaction/Koch phenomenon) is the forerunner of TIP, and is not excluded from the regulatory effects of sex hormones. Hormonal control of host-pathogen interaction may override genetic control. Environmental exposure to Salmonella typhi may be more frequent in males, presumably due to sex-linked differences in hygiene practices and dining-out behavior. A plausible explanation of male dominance in TIP could include sex-linked differences in the degree of natural exposure of Peyer’s patches to S. typhi. An alternative explanation may include sexual dimorphism in host inflammatory response patterns in Peyer’s patches that have been induced by S. typhi. Both hypotheses are testable.

Localized suppression of inflammation at sites of Helicobacter pylori colonization

While gastric adenocarcinoma is the most serious consequence of Helicobacter pylori infection, not all infected persons develop this pathology. Individuals most at risk of this cancer are those in whom the bacteria colonize the acid-secreting region of the stomach and subsequently develop severe inflammation in the gastric corpus. It has been reported anecdotally that male mice become infected with greater numbers of H. pylori bacteria than female mice. While investigating this phenomenon, we found that increased H. pylori infection densities in male mice were not related to antibody production, and this phenomenon was not normalized by gonadectomy. However, the gastric pH in male 129/Sv mice was significantly elevated compared with that in female mice. Differences in colonization were evident within 1 day postinfection and significantly arose due to colonization of the gastric corpus region in male mice. This provided a potential model for comparing the effect of corpus colonization on the development of gastritis. This was explored using two models of H. pylori-induced inflammation, namely, 2-month infections of Muc1(-/-) mice and 6-month infections of wild-type 129/Sv mice. While H. pylori infection of female mice induced a severe, corpus-predominant atrophic gastritis, to our surprise, male mice developed minimal inflammation despite being colonized with significantly more H. pylori bacteria than female controls. Thus, colonization of the gastric corpus in male mice was associated with a loss of inflammation in that region. The suppression of inflammation concomitant with infection of the gastric corpus in male mice demonstrates a powerful localized suppression of inflammation induced at sites of H. pylori colonization.

Is stomach spontaneously ageing? Pathophysiology of the ageing stomach

During ageing, histological and physiological modifications occur in the stomach leading to a confirmed state of gastric frailty defined by a decreased capacity of tissue repairing after mucosa gastric aggression. The process of intrinsic gastric ageing may play a role in inducing abnormalities of gastric epithelial proliferation against injury but, most of the time, pathophysiological modifications observed in older people are the consequences of chronic insults, such as chronic Helicobacter pylori infection, polymedication, especially Proton-pump inhibitors (PPI) and Non-steroidal Anti-inflammatory Drugs (NSAID), and co morbidities. One of the major clinical consequences of the gastric frailty is the higher vulnerability to the occurrence of peptic ulcer disease during ageing. In this review recent data on gastric changes during ageing, focussing especially on histological modifications and motility disorders are summarized.

Infection in the elderly

Many functional, demographic, and immunologic changes associated with aging are responsible for increasing the incidence and severity of infectious diseases in the elderly. Management is complicated by age-related organ system changes. Because many of the elderly are on multiple medications for underlying illnesses, antimicrobial therapy needs to be chosen keeping drug interactions and adverse events in mind. Common infections seen in the elderly are infections of skin and soft tissue, urinary tract, respiratory tract, and gastrointestinal tract. Organized and well-funded programs to address infectious disease issues in the elderly are the only way to improve care.

Placement of the Bravo wireless pH monitoring capsule onto the gastric wall under endoscopic guidance

BACKGROUND

The Bravo system was designed mainly to monitor esophageal pH, and there have been no reports on gastric pH monitoring using this system.

OBJECTIVE

To place the Bravo capsule on the gastric wall and monitor gastric pH.

DESIGN

Experimental clinical trial with the cooperation of volunteers.

SETTING

Academic medical center.

PATIENTS

Eleven volunteers (9 men, 2 women; mean age 38 years; 3 had symptoms of GERD).

INTERVENTIONS

The Bravo system was introduced into the esophagus and stomach along a thin endoscope and capsules were attached, one each to the esophageal and gastric walls under direct vision through the endoscope. Esophageal and gastric pHs were simultaneously monitored.

RESULTS

The 2 capsules were successfully placed in 10 of the 11 subjects, and both esophageal and gastric pHs were monitored for 48 hours in 9 subjects. Mild to moderate precordial pain was observed in 7 subjects, but no other complications or side effects were observed in this study. The gastric pH of 10 subjects increased after meals and returned to baseline pH 2 hours later. Decrease of esophageal pH was observed 1 hour after a meal in the symptomatic subjects and corresponded to the time when gastric pH decreased secondary to the increase of pH with meals.

CONCLUSIONS

The Bravo capsule is easily placed on the gastric wall under endoscopic assistance and enables long ambulatory monitoring of gastric pH.

Analysis of the acidity index and integrated intragastric acidity in 645 patients presenting with gastroesophageal reflux disease symptoms

OBJECTIVE

In a recent study of patients receiving proton-pump inhibitor (PPI) therapy, a new parameter, the acidity index, was described as being less complicated to calculate and of comparable accuracy (r = 0.93) to integrated intragastric acidity (IA) in assessing intragastric pH control. The aim of this study was to correlate AI with IA using a large database of ambulatory 24-h pH-metry studies in untreated patients presenting with gastroesophageal reflux disease (GERD) symptoms.

MATERIAL AND METHODS

We retrospectively analyzed 645 studies obtained from 1995 to 2001. Daytime (0800 h-2200 h), night-time (2200 h-0800 h) and 24-h IA and AI were calculated according to age, gender and the presence or absence of GERD, and correlations between these parameters were assessed using linear regression with F-statistic values, p-values and Akaike's Information Criterion values. GERD was defined as total esophageal pH time <4.0, 5 cm above the lower esophageal sphincter, for > or =4.2% of the day. IA and AI were calculated as follows: IA (mmol x h/l) = summation operator(acid in mmol/l at time "t" + acid in mmol/l at time "t - 1")/2 x ("t"-"t - 1"); AI = (%time pH < 4-%time pH < 3) x 1+(%time pH < 3-%time pH < 2) x 10+(%time pH < 2-%time pH < 1) x 100 + (%time pH < 1-%time pH < 0.8) x 1000.

RESULTS

Overall, the mean 24-h IA value was 882.0+/-820.0 mmol x h/l (daytime 392.0+/-400.0, night-time 490.0+/-486.0). The mean 24-h AI value was 102.0+/-87.0 (daytime 86.0+/-80.0, night-time 120.0+/-114.0, p < 0.001). The mean 24-h IA value was 1057.0+/-829.4 mmol x h/l (daytime 459.8+/-406.0, night-time 597.2+/-500.4, p < 0.001) in GERD patients and 713.0+/-775.0 mmol x h/l (daytime 326.0+/-383.0, night-time 387.0+/-448.5) in non-GERD patients (p < 0.001). The mean 24-h AI value was 122.1+/-88.1 (daytime 101.4+/-82.5, night-time 145.3+/-120.7) in GERD patients and 83.0+/-81.0 (daytime 71.0+/-73.9, night-time 96.4+/-102.6) in non-GERD patients (p < 0.001). Our statistical modeling demonstrated that the correlation between the acidity index and IA becomes progressively poorer with increasing values of acidity.

CONCLUSIONS

We conclude that gastric acid production assessed by both IA and AI is higher during evening hours in comparison with daytime hours and the difference between night-time and daytime values is statistically significant. In addition, gastric acid production assessed by both IA and AI is significantly higher in GERD patients than non-GERD patients. This difference is primarily due to differences in nocturnal acid production. The AI correlates poorly with measured IA, especially at higher levels of gastric acidity. Therefore, AI is not an acceptable surrogate for IA in assessing gastric acid production.

Postprandial oesophageal integrated acidity is a reliable predictor of gastro-oesophageal reflux disease

BACKGROUND

Measurement of oesophageal acid exposure parameters postprandially has been shown to distinguish gastro-oesophageal reflux disease patients from normal individuals.

AIMS

To calculate the accuracy of postprandial oesophageal integrated acidity in diagnosing gastro-oesophageal reflux disease.

METHODS

Ambulatory 24-h pH studies of 626 patients were analysed retrospectively. Gastro-oesophageal reflux disease, defined as pH < 4 for > 4.2% of time, was identified in 305 subjects. Postprandial oesophageal integrated acidity was measured for 2 and 3 h after the largest meal peak as determined from gastric pH. Postprandial symptom-associated probability was calculated.

RESULTS

Gastro-oesophageal reflux disease subjects had a greater postprandial oesophageal integrated acidity than non-gastro-oesophageal reflux disease subjects [median (IQR): 0.57 (0.08-2.66) vs. 0.03 (0.01-0.15) mmol*h/L]. Median postprandial oesophageal integrated acidity did not differ with gender or age in gastro-oesophageal reflux disease and non-gastro-oesophageal reflux disease subjects (P > 0.05 for all). A 3-h postprandial oesophageal integrated acidity value of 0.121 mmol*h/L had a 71.1% sensitivity and 71.7% specificity in diagnosing gastro-oesophageal reflux disease. Gastro-oesophageal reflux disease subjects with symptoms had a higher postprandial oesophageal integrated acidity than those without (P = 0.043), whereas non-gastro-oesophageal reflux disease subjects with and without symptoms did not differ (P = 0.74). The correlation between symptom-associated probability and postprandial oesophageal integrated acidity was poor (gastro-oesophageal reflux disease: r = 0.15; non-gastro-oesophageal reflux disease: r = 0.25).

CONCLUSION

Postprandial oesophageal integrated acidity provides a robust estimation of oesophageal acid exposure and may predict symptoms in gastro-oesophageal reflux disease patients.

The effect of rabeprazole on regional gastric acidity and the postprandial cardia/gastro-oesophageal junction acid layer in normal subjects: a randomized, double-blind, placebo-controlled study

BACKGROUND

Postprandial intragastric acidity is not uniform. Postprandial proximal gastric acid pockets have been described in the present study.

AIM

To determine the effects of rabeprazole on regional intragastric acidity and proximal acid pockets.

METHODS

Ten normal subjects underwent two 8-day oral dosing regimens with placebo or rabeprazole 20 mg each morning in a randomized, double-blind protocol. Oesophago-gastric pH monitoring was performed on days 1 and 8.

RESULTS

Rabeprazole increased fasting and postprandial gastric pH to above 4 in each area of the stomach on days 1 and 8. With placebo, acid pockets were identified at the cardia/gastro-oesophageal junction in 62 and 50 of 150 pull-throughs on days 1 and 8, respectively. Acid pockets were detected postprandially 3.1 +/- 0.2-5.8 +/- 0.1 cm below the proximal border of the lower oesophageal sphincter with a mean pH drop from 4.6 +/- 0.1 to 1.5 +/- 0.1. Rabeprazole decreased the number of acid pockets to 30 and 27 on days 1 and 8, respectively. Rabeprazole also decreased their length and magnitude of the pH drop.

CONCLUSIONS

Rabeprazole increased intragastric pH on day 1 and 8 and maintained an elevated pH during and after meals. Postprandial acid pockets, identified in the region of the cardia/gastro-oesophageal junction area postprandially, were decreased in number, length and magnitude by rabeprazole.

Somatostatin inhibits gastric acid secretion more effectively than pantoprazole in patients with peptic ulcer bleeding: a prospective, randomized, placebo-controlled trial

OBJECTIVE

Gastric acid inhibition is beneficial in the management of peptic ulcer bleeding (PUB). The aim of this double-blind study was to test whether somatostatin (SST) increases intragastric pH in PUB as compared with pantoprazole (PAN) and placebo (PLA).

MATERIAL AND METHODS

Eligible patients were randomized to receive SST (500 microg/h+250 microg bolus), or PAN (8 mg/h+80 mg bolus) or PLA (normal saline) i.v., for 24 h. All patients underwent gastric pH monitoring during the infusion of the trial drugs.

RESULTS

The three groups (SST, n=14; PAN, n=14; PLA, n=15) were comparable for age, gender, aetiology of PUB and laboratory data at admission. Mean (+/-SE) baseline pH levels in the fundus increased during the administration of the trial drugs (SST: 1.94+/-0.18 to 6.13+/-0.37, p<0.0001; PAN: 1.93+/-0.16 to 5.65+/-0.37, p<0.0001; PLA: 1.86+/-0.12 to 2.10+/-0.15, p=0.0917). During the first 12 h of infusion, the mean (+/-SE) percentage time spent above pH 4.0 and 5.4 was higher with SST versus PAN (84.4%+/-4.8 versus 55.1%+/-8.3, p=0.0049 and 74.2%+/-6.5 versus 47.1%+/-8.3, p=0.0163, respectively) and there was a trend favouring the SST group regarding the time spent above pH 6.0 and 6.8 (65.7%+/-6.4 versus 43.3%+/-8.2, p=0.0669 and 49.2%+/-7.7 versus 28.4+/-6.6, p=0.0738, respectively).

CONCLUSIONS

In PUB, both SST and PAN inhibit gastric acid secretion as compared with placebo. However, during the first 12 h of the infusion, SST was more effective than PAN in maintaining high intragastric pH. These results may provide a rationale for the administration of SST in PUB.

Increased stress tolerance of Bifidobacterium longum and Lactococcus lactis produced during continuous mixed-strain immobilized-cell fermentation

AIMS

The effect of immobilization and long-term continuous culture was studied on probiotic and technological characteristics of lactic acid and probiotic bacteria.

METHODS AND RESULTS

A continuous culture in a two-stage system was carried out for 17 days at different temperatures ranging from 32 to 37 degrees C, with a first reactor containing Bifidobacterium longum ATCC 15707 and Lactococcus lactis subsp. lactis biovar. diacetylactis MD immobilized separately in gel beads, and a second reactor operated with free cells released from the first reactor. The tolerance of free cells from both strains produced in the effluent medium of both reactors to hydrogen peroxide, simulated gastric and intestinal juices, antibiotics and nisin, and freeze-drying markedly increased with culture time and was generally higher after 6 days than that of stationary-phase cells produced during free-cell batch fermentations. The reversibility of the acquired tolerance of B. longum, but not L. diacetylactis, to antibiotics was shown during successive free-cell batch cultures.

CONCLUSIONS

Free cells produced from continuous immobilized-cell culture exhibited altered physiology and increased tolerance to various chemical and physico-chemical stresses.

SIGNIFICANCE AND IMPACT OF THE STUDY

Continuous culture with immobilized cells could be used to produce probiotic and lactic acid bacteria with enhanced technological and probiotic characteristics.