Nerve activity recordings in routine human intestinal biopsies
- Correspondence to Professor Pieter Vanden Berghe, Laboratory for Enteric Neuroscience (LENS), TARGID, KU Leuven, O&N 1 Herestraat 49 – box 701, Leuven 3000, Belgium;
Contributors Study concept and design, acquisition of data, analysis and interpretation of data, drafting and editing of the manuscript: CC and PVB. Statistical analysis: CC. JT provided biopsy material and critically revised the manuscript. PVB wrote the analysis software. JT and PVB obtained funding.
- Revised 30 January 2012
- Accepted 31 January 2012
- Published Online First 2 March 2012
Background Most direct understanding of enteric nerve (patho)physiology has been obtained by electrode and imaging techniques in animal models and human surgical samples. Until now, neuronal activity recordings from a more accessible human tissue source have remained a true challenge.
Objectives To record nerve activity in human intestinal biopsies using imaging techniques.
Design Submucous plexus was isolated from duodenal biopsies. Enteric nerves were functionally and morphologically examined using calcium (Ca2+) imaging and immunohistochemistry. Exogenous application of high-K+ solution, the nicotinic cholinergic receptor agonist (1,1-dimethyl-4-phenylpiperazinium; DMPP) or serotonin (5-HT), and electrical stimulation of interganglionic fibre tracts were used to activate the neurons, and intracellular Ca2+ concentrations ([Ca2+]i) were monitored. Enteric ganglia were stained with neuronal and glial markers.
Results Using high-K+ solution, 146 neurons were identified in 70 ganglia (44 biopsies from 29 subjects). The exogenous application of DMPP or 5-HT caused a transient [Ca2+]i increase, respectively, in 68% and 63% of the neurons identified by high-K+. Electrical stimulation evoked responses in 57% of the neurons; these responses were totally or partly suppressed by tetrodotoxin or zero-Ca2+ solution, respectively. Immunohistochemical analysis showed both isolated neurons and ganglia interconnected by typical interganglionic fibre bundles. The average number of ganglia was 7.7±6.0 per biopsy and each ganglion contained on average 4.5±1.2 neurons.
Conclusion In this study, for the first time, live recordings were performed of nerve activity in intestinal biopsies. This novel approach is of key importance to study living neurons in both health and disease and to test newly developed compounds in an in-vitro human tissue model.
- calcium imaging
- enteric nervous system
- enteric neurones
- enteric neurons
- functional bowel disorder
- functional dyspepsia
- gastric emptying
- gastroduodenal motility
- gastroesophageal reflux disease
- gastrointesinal endoscopy
- gastrointestinal motility
- intestinal biopsies
- intracellular signalling
- irritable bowel syndrome
- optical recording
- visceral sensitivity
Funding This work was funded by Methusalem (BOF, KU Leuven, JT) and FWO (G.0501.10, PVB). This work was funded only by academic funding bodies (University and Scientific Council, Flanders, Belgium).
Competing interests None.
Patient consent Obtained.
Ethics approval The study protocol (ML7400) was approved by the Ethics Committee of Leuven University Hospital, Leuven, Belgium.
Provenance and peer review Not commissioned; internally peer reviewed.