Gastric pH and Gastric Residence Time in Fasted and Fed Conscious Cynomolgus Monkeys Using the Bravo® pH System

Chen, Emile P.; Doan, Kelly M. Mahar; Portelli, Samm; Coatney, Robert W.; Vaden, Vernal; Shi, Wei

doi:10.1007/s11095-007-9358-5

Cited by 46 publications

(45 citation statements)

References 42 publications

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“…This has been used to monitor the intra-gastric pH in non-human primates and it was found that whilst the pH in the fasted stomach is indeed around pH 2, this rises to a peak above pH 4 (median around pH 5) within 30 minutes after a meal and gradually returns within several hours to the fasted state pH (Chen et al, 2008). This has been used to monitor the intra-gastric pH in non-human primates and it was found that whilst the pH in the fasted stomach is indeed around pH 2, this rises to a peak above pH 4 (median around pH 5) within 30 minutes after a meal and gradually returns within several hours to the fasted state pH (Chen et al, 2008).…”

Section: Models For Gastrointestinal Digestion Of Allergenic Proteinsmentioning

confidence: 99%

Scientific Opinion on the assessment of allergenicity of GM plants and microorganisms and derived food and feed

2010

EFSA Journal

409

231

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The weight-of-evidence, case-by-case approach is considered the most appropriate way of assessing the allergenicity of genetically modified (GM) food and feed. This scientific opinion discusses various aspects to increase the strength and accuracy of this approach, including the latest developments pertaining to clinical aspects of allergic reactions, structural aspects of GM food and feed and in silico approaches, as well as IgE binding studies and cell-based methods, profiling techniques and animal models. In this context, conclusions and recommendations are provided to update and complement current risk assessment strategies for the allergenicity assessment of newly expressed protein(s) and whole GM food and feed. In summary, it is recommended that with regard to the search for sequence homology and structural similarities, the local alignment method with a known allergen with a threshold of 35% sequence identity over a window of at least 80 amino acids is considered a minimal requirement. When IgE binding tests are considered necessary, e.g. when there is sequence homology and/or structure similarity with known allergens, the use of individual sera from allergic individuals rather than pooled sera is recommended. In addition to the pepsin resistance test, it is recommended that the resistance to digestion of the newly expressed proteins is evaluated using other in vitro digestibility tests mimicking physiological conditions of humans. Finally, when the recipient of the introduced gene is allergenic, in order to compare the allergenicty of the whole GM plant with that of its appropriate comparator(s), it is recommended that relevant characterised endogenous allergens are included in the comparative compositional analysis of the GM plant and its appropriate comparator(s). Proposals for the use of additional testing that may improve the weight-of-evidence approach and 1 On request of EFSA, Question No EFSA-Q-2005-125, adopted on 30 June 2010. 2 Panel members:

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Section: Models For Gastrointestinal Digestion Of Allergenic Proteinsmentioning

confidence: 99%

Scientific Opinion on the assessment of allergenicity of GM plants and microorganisms and derived food and feed

2010

EFSA Journal

409

231

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“…The main goal of this study was to test the feasibility of a capsule normally used in the clinical setting in humans to measure gastroesophageal reflux disease (Bravo system) for monitoring intragastric pH in the rat. The Bravo capsule system has primarily been used in humans [11][12][13][14] , but also in animals [15] for diagnosis of gastroesophageal reflux disease.…”

Section: Rudholm T Et Al Novel Technique Measures Rat Gastric Ph 6181mentioning

confidence: 99%

Bravo capsule system optimizes intragastric pH monitoring over prolonged time: Effects of ghrelin on gastric acid and hormone secretion in the rat

Rudholm¹,

Hellström²,

Theodorsson³

et al. 2008

WJG

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AIM:To evaluate measurements of intragastric pH with the Bravo capsule system over a prolonged time. METHODS: A Bravo capsule was placed inside the rat gastric body and pH was studied for periods up to five consecutive days. For comparison, a gastric fistula model was used. Effects of ghrelin and esomeprazole, with or without pentagastrin, on gastric pH were studied. In addition, effects of esomeprazole on plasma ghrelin, gastrin and somatostatin were analyzed. RESULTS: All rats recovered after surgery. The average 24-h pH during free feeding was 2.3 ± 0.1 (n = 20) with a variation of 18% ± 6% over 5 d. Ghrelin, 2400 pmol/kg, t.i.d. increased pH from 1.7 ± 0.1 to 3.1 ± 0.3 (P < 0.01) as recorded with the Bravo system. After esomeprazole (1 mg/kg, 3 mg/kg and 5 mg/kg) there was a dose-dependent pH increase of maximally 3.4 ± 0.1, with day-to-day variation over the entire period of 8% ± 3%. The fistula and pH studies generated similar results. Acid inhibition with esomeprazole increased plasma ghrelin from 10 ± 2 pmol/L to 65 ± 26 pmol/L (P < 0.001), and somatostatin from 10 ± 2 pmol/L to 67 ± 18 pmol/L (P < 0.001). CONCLUSION: pH measurements with the Bravo capsule are reliable, and comparable to those of the gastric fistula model. The Bravo system optimizes accurate intragastric pH monitoring over prolonged p e r i o d s a n d a l l o w s b o t h s h o r t-a n d l o n g -t e r m evaluation of effects of drugs and hormones.

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“…In various cases, including early childhood or elderly age, during a meal or while taking antacid medication, the pH of the stomach increases above 4 and/or the gastric pepsin concentration and activity decrease Chen et al, 2008;Grassi et al, 2011;Minekus et al, 2014;Untersmayr et al, 2005). More physiologically relevant tests have recently been developed (Mills et al, 2013).…”

Section: Enzymatic Degradation Assaysmentioning

confidence: 99%

Approaches to assess IgE mediated allergy risks (sensitization and cross-reactivity) from new or modified dietary proteins

Remington¹,

Broekman

Blom³

et al. 2018

Food and Chemical Toxicology

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A B S T R A C TThe development and introduction of new dietary protein sources has the potential to improve food supply sustainability. Understanding the potential allergenicity of these new or modified proteins is crucial to ensure protection of public health. Exposure to new proteins may result in de novo sensitization, with or without clinical allergy, or clinical reactions through cross-reactivity.In this paper we review the potential of current methodologies (in silico, in vitro degradation, in vitro IgE binding, animal models and clinical studies) to address these outcomes for risk assessment purposes for new proteins, and especially to identify and characterise the risk of sensitization for IgE mediated allergy from oral exposure. Existing tools and tests are capable of assessing potential crossreactivity. However, there are few possibilities to assess the hazard due to de novo sensitization. The only methods available are in vivo models, but many limitations exist to use them for assessing risk. We conclude that there is a need to understand which criteria adequately define allergenicity for risk assessment purposes, and from these criteria develop a more suitable battery of tests to distinguish between proteins of high and low allergenicity, which can then be applied to assess new proteins with unknown risks.

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Gastric pH and Gastric Residence Time in Fasted and Fed Conscious Cynomolgus Monkeys Using the Bravo® pH System

Cited by 46 publications

References 42 publications

Scientific Opinion on the assessment of allergenicity of GM plants and microorganisms and derived food and feed

Scientific Opinion on the assessment of allergenicity of GM plants and microorganisms and derived food and feed

Bravo capsule system optimizes intragastric pH monitoring over prolonged time: Effects of ghrelin on gastric acid and hormone secretion in the rat

Approaches to assess IgE mediated allergy risks (sensitization and cross-reactivity) from new or modified dietary proteins

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