Fluorescence imaging in vivo visualizes delayed gastric emptying of liquid enteral nutrition containing pectin

Semi-solidification by gelation or increased viscosity could slow the influx of liquid enteral nutrition (EN) into the small intestine. A liquid EN formula containing pectin that gels under acidic conditions such as those found in the stomach has been developed. A new near-infrared fluorescent imaging reagent was used to non-invasively acquire real time images of gastric emptying in a murine model in vivo. We postulated that the EN formula delays gastric emptying and tested this hypothesis using imaging in vivo.

Male BALB/c mice were given an oral bolus injection of a liquid EN containing the fluorescence reagent GastroSense750 with or without pectin. The EN in the stomach was visualized in vivo at various intervals using a non-invasive live imaging system and fluorescent signals were monitored from the stomach, which was removed at 60 min after EN ingestion.

The fluorescence intensity of signals in stomachs in vivo and in resected stomachs was lower and attenuated over time in mice given EN without, than with pectin.

Adding a gelling agent such as pectin delayed the transit of liquid EN from the stomach. Fluorescence imaging can visualize the delayed gastric emptying of EN containing pectin.