Background: Intestinal pacing (IP) has been previously shown to delay gastric emptying and reduce food intake in animals. The aims of this study were to investigate the effect and mechanism of IP on nutrient absorption in healthy volunteers.
Methods: Twelve healthy volunteers (six men, six women) were involved in a two-session (one session without IP and one with IP) study. At the beginning of each session, a nasal-duodenal feeding tube, with two ring electrodes (used for IP) on the tip of the tube, was incubated into the duodenum under endoscopy. After a complete recovery from the incubation, the duodenum was infused via the feeding tube with 150 ml 30% intralipid + 25 g D-xylose within 30 min, and the stool was collected for 24 h for the analysis of fecal lipid during which a controlled meal was taken. Then 100 ml 1mCi(99)Tc-labeled non-absorbable solution was infused within 3 min. The subject was asked to lie under a gamma camera for at least 1 h for the measurement of small bowel transit. The movement of isotopes was monitored by gamma camera at an interval of 10 s. The first appearance of isotopes in the cecum was considered as small intestinal transit time. The order of the two sessions was randomized and 1 week apart. In the IP session, intestinal pacing was performed via the pair of the ring electrodes for 2 h initiated at the beginning of infusion with a pacing frequency of 13 pulses/min, pulse width of 300 ms and amplitude of 5 mA.
Results: (1) IP significantly reduced lipid and D-xylose absorption. The fecal lipid was 6.6 +/- 4.6 g without IP and almost doubled with IP (11.1 +/- 6.5 g, P = 0.047). Similarly, the D-xylose in urine was 3.46 +/- 2.22 g with IP, which was significantly lower than that without IP (6.63 +/- 5.06 g, p = 0.049). (2) IP accelerated intestinal transit. The transit time was 39 +/- 17 min in the control session and reduced to 28 +/- 10 min in the IP session (p < 0.03). (3) Diarrhea was reported in one subject without IP but in six subjects with IP (p < 0.05).
Conclusions: The increased fecal lipid and induction of diarrhea with intestinal pacing suggest that intestinal pacing is capable of inducing malabsorption. This effect maybe contributed to the acceleration of intestinal transit.