Plasma ghrelin and liquid gastric emptying in children with functional dyspepsia consistent with post-prandial distress syndrome

Therapeutic potential of ghrelin/GOAT/GHSR system in gastrointestinal disorders

Ghrelin, a peptide primarily secreted in the stomach, acts via the growth hormone secretagogue receptor (GHSR). It regulates several physiological processes, such as feeding behavior, energy homeostasis, glucose and lipid metabolism, cardiovascular function, bone formation, stress response, and learning. GHSR exhibits significant expression within the central nervous system. However, numerous murine studies indicate that ghrelin is limited in its ability to enter the brain from the bloodstream and is primarily confined to specific regions, such as arcuate nucleus (ARC) and median eminence (ME). Nevertheless, the central ghrelin system plays an essential role in regulating feeding behavior. Furthermore, the role of vagal afferent fibers in regulating the functions of ghrelin remains a major topic of discussion among researchers. In recent times, numerous studies have elucidated the substantial therapeutic potential of ghrelin in most gastrointestinal (GI) diseases. This has led to the development of numerous pharmaceutical agents that target the ghrelin system, some of which are currently under examination in clinical trials. Furthermore, ghrelin is speculated to serve as a promising biomarker for GI tumors, which indicates its potential use in tumor grade and stage evaluation. This review presents a summary of recent findings in research conducted on both animals and humans, highlighting the therapeutic properties of ghrelin system in GI disorders.

Liquid and solid gastric emptying and correlation with clinical characteristics in pediatric patients with dyspepsia

BACKGROUND

There is limited data on gastric emptying in dyspeptic children. We aimed to determine solid and liquid emptying rates in dyspeptic children and correlate with clinical characteristics.

METHODS

Charts of dyspeptic children undergoing 4-hour dual-phase gastric scintigraphy were reviewed for demographics, symptoms, and comorbidities.

KEY RESULTS

In 1078 dyspeptic patients (65% females, median age 13 years) vomiting (55%), nausea (53%), and abdominal pain (52%) were the most common symptoms. The most common comorbidities were mental health (32%), neurologic (27%), and hypermobility spectrum disorders (20%). Solid and liquid emptying rates were aligned in 61.23%. Delayed solid with normal liquid emptying were noted in 2.5%, compared to delayed liquid with normal solid emptying in 26.16%. Abdominal pain had a trend for association with delayed or normal solid emptying (p = 0.06). Nausea was mostly reported with normal solid emptying (p < 0.0001) and underreported in patients <12 years with vomiting (29%). Abnormal solid emptying (rapid and delayed) was noted more frequently in children with mental health disorders (p = 0.027). Rapid liquid emptying was more common in children with genetic disorders (p = 0.032).

CONCLUSION AND INFERENCES

Over half of children with dyspepsia had delayed liquid gastric emptying, and one quarter had delayed liquid with normal solid emptying. Dual-phase gastric emptying studies may help target therapy in dyspeptic children. Nausea is not a reliable symptom for dyspepsia in younger children. Given the significant association of abnormal gastric emptying in children with mental health disorders, we recommend screening and treating children with dyspepsia.

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

Brain to Belly: Abdominal Variants of Migraine and Functional Abdominal Pain Disorders Associated With Migraine

Migraine is one of the most frequent causes of primary headache and 9% of children suffer from migraines. Most children will continue to experience migraine attacks as adults, therefore it is imperative that we have a thorough understanding of this major health issue. This article considers the so-called abdominal variants of migraine, which are more commonly seen in children rather than adults: abdominal migraine, cyclic vomiting syndrome, and infantile colic. Other functional abdominal pain disorders such as irritable bowel syndrome and functional dyspepsia have also been linked to migraine in clinical studies. The common pathophysiological root of these diseases seems to be the gut-brain axis mechanism. Abdominal variants of migraine are considered pediatric precursors of migraine whereas the functional abdominal pain disorders related to migraine seem to share a pathophysiological root with no temporarily link as for today. In this review we aim to describe the epidemiological background, the current pathophysiological theories and the relationship of each disease to migraine. This review is the first to compile abdominal variants of migraine and functional abdominal pain disorders associated with migraine and we endeavor to elucidate the broad spectrum of migraine-related episodes in children.

Plasma dosage of ghrelin, IGF-1, GLP- 1 and leptin related to gastric emptying and esophageal pH-impedance in children with obesity

PURPOSE

The main aim of the study was to assess the relationship between leptin, ghrelin, insulin-like growth factor 1 (IGF-1), and glucagon-like peptide 1 (GLP-1) blood levels and gastric motility in children with obesity compared to healthy children. Secondary aims were to assess the possible association between these hormones and obesity, reflux impedance parameters, reflux symptoms, other GI disorders, and quality-of-life scores within the same groups.

METHODS

Children with obesity plus GERD symptoms and 2 control groups of children with obesity without GERD and healthy lean children aged 4-17 years underwent an auxological evaluation, an assessment of gastro-intestinal symptoms and quality of life, hormonal dosages, and an evaluation of gastric emptying time (GET) through 13C-octanoic acid breath test.

RESULTS

No significant association was found between hormones and gastric motility. Leptin and ghrelin levels were significantly associated with obesity parameters. No significant differences were found between GET and hormones of the patients with obesity, either with or without GERD.

CONCLUSION

Although we found an association between auxological parameters and both leptin and ghrelin levels, this association did not imply an effect on the upper GI motility. Therefore, our hypothesis that alterations of these hormones in children with obesity could affect gastric emptying, triggering GERD, was not supported by our data.

Electrogastrographic and autonomic nervous system responses to solid and liquid meals in youth with functional dyspepsia

BACKGROUND

Meal-related symptoms are common in paediatric functional dyspepsia (FD). There are only a small number of paediatric studies assessing mechanisms for meal-related symptoms, and these have not utilized Rome IV criteria. The aim of the current study was to assess gastric myoelectric and autonomic nervous system (ANS) responses to both liquid and solid meals in youth with Rome IV-defined FD.

METHODS

In healthy controls (N = 14) and youth with FD (N = 12), we recorded electrocardiograph (to assess heart rate variability; HRV) and electrogastrograph (EGG) signals before and after two test meals, one liquid and one solid. EGG parameters and HRV were assessed for the entire pre- and postprandial periods and in short time intervals. Additionally, liquid gastric emptying was assessed utilizing a ¹³ C-acetate breath test.

KEY RESULTS

During the EGG, the dominant power increased with both meals in controls but not patients with FD. During HRV assessment, the low frequency to high frequency ratio was higher after the liquid meal in controls, despite being similar preprandial, as compared to patients with FD. In controls, both standard deviation of normal to normal waves (SDNN) and root mean square of successive ECG R peaks (R-R interval) differences (rMSSD) increased after the liquid meal (but not after the solid meal) in controls but not patients with FD.

CONCLUSIONS AND INFERENCES

Youth with Rome IV-defined FD lacks the normal postprandial EGG dominant power response or autonomic nervous system response following a liquid meal. The latter appears to indicate a lack of ANS flexibility.

Role of Gut Microbiota-Gut Hormone Axis in the Pathophysiology of Functional Gastrointestinal Disorders

Gut microbiota exert a pivotal influence on various functions including gastrointestinal (GI) motility, metabolism, nutrition, immunity, and the neuroendocrine system in the host. These effects are mediated by not only short-chain fatty acids produced by microbiota but also gut hormones and inflammatory signaling by enteroendocrine and immune cells under the influence of the microbiota. GI motility is orchestrated by the enteric nervous system and hormonal networks, and disturbance of GI motility plays an important role in the pathophysiology of functional gastrointestinal disorders (FGIDs). In this context, microbiota-associated mediators are considered to act on specific receptors, thus affecting the enteric nervous system and, subsequently, GI motility. Thus, the pathophysiology of FGIDs is based on alterations of the gut microbiota/gut hormone axis, which have crucial effects on GI motility.