Motility disorders in childhood

Effects of Amoxicillin and Clavulanic Acid on the Spontaneous Mechanical Activity of Juvenile Rat Duodenum

OBJECTIVES

There are a limited number of medications for the treatment of foregut dysmotility. Enteral amoxicillin/clavulanic acid induces phase III duodenal contractions in a fasting pediatric patient. The mechanism by which this occurs is unknown. We examined the individual contributions of amoxicillin and clavulanic acid on the spontaneous mechanical activity of juvenile rat duodenum to better understand this phenomenon.

METHODS

Duodenal segments from juvenile rats were longitudinally attached to force transducers in organ baths. Samples were cumulatively exposed to amoxicillin or clavulanic acid. Separate samples were exposed to carbachol alone to assess response in both the presence and absence of amoxicillin or clavulanic acid. Basal tone, frequency, and amplitude of contractions were digitized and recorded.

RESULTS

The amplitude of the spontaneous contractions increased with amoxicillin. Inhibition of neuronal activity prevented this effect. Clavulanic acid did not affect the spontaneous contractions. Basal tone and the rate of contractions did not differ with either drug. Stimulation with carbachol in the presence of amoxicillin caused a statistically significant increase in the contractility compared with carbachol alone.

CONCLUSIONS

Amoxicillin alters the spontaneous longitudinal mechanical activity of juvenile rat duodenum. Our results suggest that amoxicillin modulates the spontaneous pattern of cyclic mechanical activity of duodenal smooth muscle through noncholinergic, neurally mediated mechanisms. Our work provides an initial physiologic basis for the therapeutic use of amoxicillin in patients with gastrointestinal dysmotility.

Plasticity and neural stem cells in the enteric nervous system

The enteric nervous system (ENS) is a highly organized part of the autonomic nervous system, which innervates the whole gastrointestinal tract by several interconnected neuronal networks. The ENS changes during development and keeps throughout its lifespan a significant capacity to adapt to microenvironmental influences, be it in inflammatory bowel diseases or changing dietary habits. The presence of neural stem cells in the pre-, postnatal, and adult gut might be one of the prerequisites to adapt to changing conditions. During the last decade, the ENS has increasingly come into the focus of clinical neural stem cell research, forming a considerable pool of neural crest derived stem cells, which could be used for cell therapy of dysganglionosis, that is, diseases based on the deficient or insufficient colonization of the gut by neural crest derived stem cells; in addition, the ENS could be an easily accessible neural stem cell source for cell replacement therapies for neurodegenerative disorders or traumatic lesions of the central nervous system.

Potential of cell therapy to treat pediatric motility disorders

Gut motility disorders represent a significant challenge in clinical management with current palliative approaches failing to overcome disease and treatment-related morbidity. The recent progress with stem cells to restore missing or defective elements of the gut neuromusculature offers new hope for potential cure. Focusing on enteric neuropathies such as Hirschsprung's disease, the review discusses the progress that has been made in the sourcing of putative stem cells and the studies into their biology and therapeutic potential. It also explores the practical challenges that must be overcome before stem cell-based therapies can be applied in the clinical arena. Although many obstacles remain, the speed of advancement of the enteric stem cell field suggests that such therapies are on the horizon.

Future horizons in the treatment of enteric neuropathies

Enteric neuropathies comprise a vast and disparate array of congenital and acquired disorders of the enteric nervous system (ENS), reflecting both the complexity of its neuronal composition and the many interactions that modulate its function. Although present therapeutic strategies, largely limited to surgery and the provision of artificial nutrition, have transformed the early survival and life of sufferers, levels of morbidity and mortality remain unacceptably high. This highlights the need to develop new treatments for enteric neuropathies. In the last decade, the tremendous advances in molecular biology and genetics have significantly enhanced our understanding of ENS development and function. Coupled with equivalent progress in the fields of pharmacology and stem-cell biology, this has led to the identification of novel tools and targets for therapy, which either aim to optimise the function of the intrinsic ENS or replace/replenish components of an inadequate or dysfunctional ENS. This article reviews current work on a number of these interventions with a particular focus on the use of ENS stem cells as potential therapeutic tools for enteric neuropathies.

Gastro-oesophageal reflux disease and motility disorders

Gastro-oesophageal reflux (GOR) is a common phenomenon occurring at any age with a benign prognosis in the majority of cases, but requiring prompt evaluation and treatment when presenting with alarm symptoms or when persisting. Complications of GOR disease (GORD) may be severe. This chapter will discuss the epidemiology, natural course, pathophysiology, clinical presentation, diagnostic and therapeutic approach towards GORD and motility disorders according to different ages. Similarities and differences between infants, children and adults will be highlighted. The superior efficacy and safety of proton pump inhibitors have recently changed the diagnostic and therapeutic recommendations in adults, and possible indications in children are discussed. Only in patients unresponsive to optimal medical treatment are further investigations to exclude other aetiologies for GORD needed (e.g. eosinophilic oesophagitis in infants, scleroderma in adults). Special patient groups such as those with congenital malformations (e.g. oesophageal atresia) are not considered, whereas neurological, respiratory and allergy-affected patients as well as Helicobacter pylori infection are briefly discussed.

Abdominal migraine: evidence for existence and treatment options

There is evidence to suggest that, in children, episodic abdominal pain occurring in the absence of headache may be a migrainous phenomenon. There are four separate strands of evidence for this: the common co-existence of abdominal pain and migraine headaches; the similarity between children with episodic abdominal pain and children with migraine headaches, with respect to social and demographic factors, precipitating and relieving factors, and accompanying gastrointestinal, neurological and vasomotor features; the effectiveness of nonanalgesic migraine therapy (such as pizotifen, propanolol, cyproheptadine and the triptans) in abdominal migraine; and the finding of similar neurophysiological features in both migraine headache and abdominal migraine. Abdominal migraine is rare, but not unknown, in adults. Many families are content with a diagnosis and reassurance that the episodes, though distressing, are not the result of serious pathology. Some patients respond to simple dietary and other prophylactic measures. There is scant evidence on which to base recommendations for the drug management of abdominal migraine. What little literature exists suggests that the antimigraine drugs pizotifen, propanolol and cyproheptadine are effective prophylactics. Nasal sumatriptan (although not licensed for pediatric use) may be effective in relieving abdominal migraine attacks.