Evaluation of the Small Intestinal Functions Using the Extracorporeal Small Intestinal Serosa Voltage Measurement Method

A rapid and non-invasive assessment method for small intestinal functions before organ transplantation has not yet been established. Machine perfusion is a novel organ preservation strategy and a promising technique that can maintain, restore, and regenerate organ functions. The purpose of this study was to develop an extracorporeal small intestinal serosa voltage measurement method to evaluate small intestinal functions during machine perfusion. The eight porcine small intestines were preserved under the following three conditions: simple cold storage (CS, n = 3); hypothermic oxygenated machine perfusion (MP) after CS (n = 3); and CS using grafts that had undergone warm ischemia (n = 2). After storage under each of these conditions, we performed reperfusion experiments at body temperature using diluted autologous blood and evaluated the status of the small intestine after transplantation. The microcomputer-recorded small intestinal serosa voltage was filtered using an IIR digital lowpass filter. The results reveal that low-frequency potential changes characteristic of the small intestinal serosa voltage were more pronounced in the group that underwent MP (0.19 ± 0.04 Hz; mean ± standard deviation; 95% confidence interval: 0.09–0.28), similar to a previous in vivo study. The amplitude root-mean-square (RMS) of the lowpass filtered waveforms showed a negative correlation with glucose concentration change and a positive correlation with oxygen consumption. The small intestinal serosa voltage reflects the health of electrically active cell populations in the muscularis, indicating its usefulness as a method for evaluating small intestinal functions during machine perfusion.