Ghrelin and Gastric Emptying in Children With Functional Dyspepsia (GHR)

May 16, 2019 updated by: Nadia Hijaz, Children's Mercy Hospital Kansas City

Evaluation of Liquid Gastric Emptying and Plasma Ghrelin in Children With Functional Dyspepsia

The purpose of this research is to see if there are differences between children who have FD and children without FD in the ability of the stomach to empty food and/or in ghrelin hormone levels before and after eating.

Chronic abdominal pain is the most common persistent pain condition in children and adolescents. One of the most often diagnosed types of abdominal pain is functional dyspepsia (FD). FD is abdominal pain or discomfort (e.g., nausea, bloating) in the upper abdomen that does not get better by having a bowel movement.

One possible explanation for having FD is a delay in the emptying of food from the stomach, or delayed gastric (stomach) emptying. Failing to empty the stomach quickly enough may result in the feeling of being full and cause symptoms of bloating, nausea, vomiting and pain. Further, hormonal changes occur before, during, or after eating food that appear to impact stomach emptying.

One of the hormones that changes with meals is called ghrelin. The relationship between ghrelin and stomach emptying needs to be explored more in children with FD. Better understanding of what causes FD symptoms may help us to improve treatment for this condition.

Study Overview

Status

Completed

Conditions

Detailed Description

Functional Dyspepsia (FD) is defined as the presence of persistent or recurrent pain or discomfort centered in the upper abdomen with no evidence of organic disease likely to explain the symptoms.

This pain or discomfort must not be exclusively relieved by defecation or associated with the onset of a change in stool frequency or stool form.

Initially, the FD classification criteria included 3 subtypes: ulcer-like, in which pain is the predominant symptom; dysmotility-like, in which discomfort is the predominant symptom; and, unspecified. In 2006, however, the criteria were revised by the Rome III committees. In adults, the previous FD subtypes were eliminated and replaced by two new subtypes: (i) postprandial distress syndrome (PDS), characterized by postprandial fullness or early satiety; and, (ii) epigastric pain syndrome (EPS), characterized by epigastric pain or burning unrelated to meals. In children, the Rome II subtypes were eliminated completely. Although the Rome III subtypes have only been applied within adult criteria, there also appear to be meaningful associations in children with FD which may support their adoption in later revisions of the criteria. Specifically, both inflammation (reflected by mast cell density) and self reported anxiety and depression appear to be uniquely associated with PDS in children.

FD is a common disorder of the upper gastrointestinal (GI) tract, occurring in 26% to 34% of the general population. FD is present in as many as 80% of children being evaluated for chronic abdominal pain. FD is best explained by a biopsychological model with dysfunction within the brain-gut axis. The model suggests that FD is as a result of interaction between biological (e.g., inflammation, mechanical, or sensory dysfunction), psychological (e.g., anxiety, depression, somatization), and social (e.g., interactions with parents, teachers, or peers) factors, which may be interactive with each other. Delayed gastric emptying is one of the mechanical factors which have been implicated. Other mechanisms are visceral hypersensitivity and impaired gastric fundic accommodation.

Delayed gastric emptying has been shown in up to 66% of children with FD. Most of previous studies in children used solid GE as a measure to explain the function of pyloric emptying. However, liquids GE is a good measure to predict the function of fundic accommodation, visceral hypersensitivity as well as pyloric emptying, in which, all these mechanisms were suggested in the mechanical pathophysiological model of FD specifically PDS subtypes. In order to measure gastric emptying (GE), the 13C-acetate breath test (ABT) has the potential to replace 99mtechnetium colloid-based scintigraphy which is the "gold standard" for measuring GE. ABT has an advantage over scintigraphy in that it is a rapid, technically simple, safe and inexpensive means to assess liquid GE in children. As such, it may be more easily utilized as a diagnostic technique in standard clinical practice.

Gastric motility is mainly regulated by extrinsic autonomic nerves, intrinsic neurons of the stomach, and GI hormones. It is hypothesized that these hormones strongly affect hunger and energy expenditure and may be are altered in dyspeptic disorders affecting gastric motility. Because altered gut-brain interactions may underlie symptom generation in FD and ghrelin is an important gut peptide related to the gut-brain axis, plasma concentrations of ghrelin in patients with FD have been investigated in several studies.

Ghrelin is a motilin-related peptide mainly synthesized and released by A-like cells in the stomach. Ghrelin acts as an endogenous ligand of growth hormone secretagogue receptor (GHSR). Ghrelin receptors are present in the anterior pituitary hypothalamus. There are two forms of ghrelin. The first form is acyl ghrelin, comprising 28 amino acid residues with an n-octanoyl ester at Ser3 that is essential for its biologic activity, which acts as an endogenous ligand of growth hormone secretagogue receptor type 1a (GHS-R1a). Acyl ghrelin is easily and rapidly degraded to the second form, desacyl ghrelin, or smaller fragments.

Functionally, ghrelin level progressively rises during fasting to peak just prior to a meal and fall to its lowest level about an hour after eating. Ghrelin level again starts increasing approximately 2 hours after eating to peak again before the next meal. A close relationship has been documented between ghrelin and gastric motility in rats. In humans, it has been demonstrated that ghrelin increases the gastric emptying rate in healthy, but not in obese, controls. Ghrelin has a well-established role in increasing appetite and food intake. These pieces of evidence have led to speculation that altered ghrelin function may contribute to the disturbed gastric motility and appetite loss seen in FD. Moreover, ghrelin agonist administration is found to have stimulatory effect on appetite in FD patients and idiopathic gastroparesis.

Considering that most symptoms of FD are typically related to food intake, postprandial ghrelin level has been investigated in several studies. It has been shown that fasting ghrelin level, in general, is inversely related to gastric emptying time (i,e., lower fasting ghrelin is associated with greater delay in GE). However, this relation is disrupted in FD patients, as these patients do not demonstrate an increase in fasting ghrelin level. Although results have been somewhat conflicting, some previous studies support a role for ghrelin in FD in adults. Takamori et al. reported that fasting desacyl and total ghrelin levels were significantly lower in FD patients than in controls. Further, fasting and postprandial levels were not significantly different in FD, as compared to a significant drop from fasting to postprandial level seen in controls, which suggests that fasting ghrelin does not increase as expected during fasting in FD patients. Consistent with this, Lee et al. showed that delayed GE has been reported in the majority of adults with FD where abnormally low total pre-prandial ghrelin levels were observed. However, the relationship between FD and ghrelin may differ by FD subtype. Shindo et al. reported that fasting acyl ghrelin levels were significantly lower in PDS adult patients than in healthy volunteers. Further, they demonstrated that Tmax value reflective of GE in PDS patients was significantly higher than in healthy volunteers, as measured using the 13-C (carbon) acetate breath test. These results suggested that acyl ghrelin is more biologically important and might play a role in the pathophysiology of the PDS subtype of FD through its effect on gastric emptying.

Collectively, previous studies suggest a relationship between plasma ghrelin concentration and FD, or FD subtype, in adults. Further, it seems likely that this occurs through the impact of ghrelin on gastric emptying in adults. However, to the best of our knowledge, the role of ghrelin in pediatric FD and it its relation to gastric motility in children has not been previously studied. There is a need to investigate the possible role of ghrelin in its two different forms, as well as its relation to gastric motility, in children with FD as a group and across possible subtypes in order to establish better understanding of the pathophysiology of FD. This study may help to build a mechanical pathway model for FD etiology, explore the pharmacokinetics of the ghrelin hormone, and establish its correlation to liquid gastric emptying. If a relationship is established, future work can explore a potential therapeutic role for ghrelin agonist in FD or specific FD subtypes.

Study Type

Observational

Enrollment (Actual)

30

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Missouri
      • Kansas City, Missouri, United States, 64108
        • Children's Mercy Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

8 years to 17 years (CHILD)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

All FD patients will be recruited from the Section of Gastroenterology at the Children's Mercy Hospital and Clinics. The control group will be recruited by advertisement within Children's Mercy Hospital.

Description

Inclusion Criteria:

  • All: Participants 8-17 years of age
  • FD arms: Patients identified in CMH/Abdominal Pain Team Clinic with Functional Dyspepsia who meet exclusion criteria.
  • Control arm: healthy participants who meet exclusion criteria.

Exclusion Criteria:

  • History of upper gastrointestinal surgery or intestinal obstruction.
  • History of disease or symptoms suggestive of underlying malabsorption, Inflammatory Bowel Disease (IBD), or Peptic Ulcer Disease (PUD).
  • History or evidence of chronic illness requiring regular medical care such as diabetes mellitis (DM), liver, heart, kidney, endocrine, or pulmonary disease and asthma that precludes accurate exhalation into the study breath collection apparatus.
  • Any patient with body Mass index (BMI) less than or equal to 10th percentile for age; or equal to or greater than 90th percentile for age.
  • Patient and/or parent not able to read English.
  • Current pregnancy.
  • History of milk allergy.
  • Prokinetic or psychotropic medications used within the last 72 hour prior to study.
  • Inability to exhale into study breath collection apparatus as directed.
  • Recent acute illness that occurs prior to study visit.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Functional Dyspepsia with PDS
Study participants 8-17 years of age will be recruited for this arm after an evaluation at Children's Mercy Hospital and Clinics in the Abdominal Pain Clinic (APC)or in the Section of Gastroenterology, general, and diagnosed with FD, fail to respond to acid suppression therapy and have Postprandial Distress Syndrome (PDS).
Functional Dyspepsia without PDS
Study participants 8-17 years of age will be recruited for this arm after an evaluation at Children's Mercy Hospital and clinics (CMH) Abdominal Pain Clinic (APC)or the Section of Gastroenterology, general, and diagnosed with FD, fail to respond to acid suppression therapy and do not have Postprandial Distress Syndrome (PDS).
Control Group
Healthy participants 8-17 years of age recruited from internal advertising within Children's Mercy Hospital and Clinics.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Children with FD: exploration of relationships between ghrelin concentration, liquid gastric emptying, and dyspepsia subtype
Time Frame: Duration of 4-hour study visit
Blood samples will be compared pre/post test meal for FD cohorts (EPS/PDS), controls: 0 time/baseline; 6 times/post meal. Associations between relationship of plasma ghrelin type's (acyl and desacyl) pre and postprandial levels & gastric emptying studied.C-13 acetate to be given and amount of 13CO2 determined for each time point (1 pre/ 14 post meal) using equation nested in software package with UBit IR-300 spectrometer. The concentration of 13CO2 and 12CO2 in the exhaled breath samples to be measured by infrared spectrometry.
Duration of 4-hour study visit

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Children with FD: SUBJECTIVE SYMPTOM SEVERITY and correlations between plasma ghrelin concentrations (acyl and desacyl) and gastric emptying.
Time Frame: Duration of 4-hour study visit
Intensity of 5 symptoms associated with FD (burning, nausea, bloating, belching, epigastric pain) will be graded x6 (1 pre and 5 post-meal).
Duration of 4-hour study visit

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Children's Mercy Hospital Kansas City

Investigators

  • Principal Investigator: Nadia M Hijaz, MD, Fellow, Children's Mercy Hospital, Section of Gastroenterology

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 1, 2012

Primary Completion (Actual)

April 22, 2016

Study Completion (Actual)

April 22, 2016

Study Registration Dates

First Submitted

May 2, 2012

First Submitted That Met QC Criteria

May 2, 2012

First Posted (Estimate)

May 3, 2012

Study Record Updates

Last Update Posted (Actual)

May 20, 2019

Last Update Submitted That Met QC Criteria

May 16, 2019

Last Verified

May 1, 2019

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Ghrelin 12010078

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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