Gastric myoelectrical activity and gut hormone secretion in myotonic dystrophy

BACKGROUND: Myotonic dystrophy (MD) is a systemic disease affecting striated, cardiac and smooth muscles, as well as nerve structures and endocrine glands. Patients with MD may suffer from slow gastric emptying. OBJECTIVE: To study electrogastrograms (EGG) and postprandial gut hormone profiles in MD in order to evaluate whether disturbances in these regulatory mechanisms could explain, or contribute to, the delayed gastric emptying. SUBJECTS: Ten patients with MD complaining of symptoms consistent with slow gastric emptying, and ten healthy matched controls. METHODS: After an overnight fast, the patients and the control subjects were examined with standard EGG using surface electrodes before and during intake of a standard meal. Blood tests were drawn at regular time intervals for hormone analyses. RESULTS: The EGG in MD showed a reduced amount of normal three cycles per minute activity compared with controls (P < 0.04). The dominant frequency in MD was less stable than in controls (P < 0.03), and the power of the signal showed less increase after a meal. The postprandial increase in plasma motilin (P < 0.05) and glucagon-like peptide-1 (GLP-1) (P < 0.001) was significantly less pronounced in MD compared with controls, whereas the plasma concentrations of cholecystokinin (CCK), neurotensin (NT), peptide YY (PYY) and somatostatin (SOM) did not differ significantly. CONCLUSION: Disturbed electrophysiological control of the stomach and impaired secretion of gastrointestinal peptide hormones could contribute to slow gastric emptying in MD. Combined impairment of gastric pacing and gastrointestinal hormone responses was found in patients with the most prominent retardation of gastric emptying.