Vagal sparing surgical technique but not stoma size affects body weight loss in rodent model of gastric bypass

Abstract

Background: The aim of this study was to evaluate whether gastric bypass with or without vagal preservation resulted in a different outcome.

Methods: Body weight, food intake and postprandial peptide YY (PYY) and glucagon-like peptide (GLP-1) levels were compared between gastric bypass (n = 55) and sham-operated rats (n = 27) in three groups. In group 1 (n = 17), the vagal nerve was not preserved, while in group 2 the vagal nerve was preserved during gastric bypass (n = 10). In group 3, gastric bypass rats (n = 28) were randomised for either one of the two techniques.

Results: Rats in which the vagal nerve was preserved during gastric bypass showed a lower body weight (p < 0.001) and reduced food intake (p < 0.001) compared to rats in which the vagal nerve was not preserved during the gastric bypass operation. Levels of PYY and GLP-1 were significantly increased after gastric bypass compared to sham-operated controls (p < 0.05), but there was no difference between gastric bypass rats with and without vagal preservation. Differences in food intake and body weight were not related to the size of the gastro-jejunostomy in gastric bypass rats. There were no signs of malabsorption or inflammation after gastric bypass.

Conclusion: We propose that the vagal nerve should be preserved during the gastric bypass operation as this might play an important role for the mechanisms that induce weight loss and reduce food intake in rats. In contrast, the gastro-jejunal stoma size was found to be of minor relevance.

Figure 1

Diagrammatic representation of the gastrointestinal anatomy before (a) and after (b) the gastric bypass operation.(A) Biliopancreatic limb (~10 cm), (B) Alimentary limb (~50 cm), (C) Common channel (~25 cm), (D) Coecum.

Figure 2

a Average daily energy intake (Group 1) over 60 days for sham-operated ad libitum fed rats (n=7, white column) and for gastric bypass rats (n=14, black column). Data are shown as mean values ± SEM. b Average daily energy intake (Group 2) over 60 days for sham-operated ad libitum fed rats (n=8, white column) and for gastric bypass rats (n=8, black column). Data are shown as mean values ± SEM (*** = p<0.001). c Average daily energy intake (Group 3) over 75 days for sham-operated ad libitum fed rats (n=10, white column) and for gastric bypass rats with selective ligation of the left gastric arterie (n=11, dark grey) or with complete ligation of the paraoesophageal bundle (n=10, light grey). Data are shown as mean values ± SEM. Post-hoc differences between the 3 groups are indicated (# = p<0.001 and † = p<0.05).

Figure 2

a Average daily energy intake (Group 1) over 60 days for sham-operated ad libitum fed rats (n=7, white column) and for gastric bypass rats (n=14, black column). Data are shown as mean values ± SEM. b Average daily energy intake (Group 2) over 60 days for sham-operated ad libitum fed rats (n=8, white column) and for gastric bypass rats (n=8, black column). Data are shown as mean values ± SEM (*** = p<0.001). c Average daily energy intake (Group 3) over 75 days for sham-operated ad libitum fed rats (n=10, white column) and for gastric bypass rats with selective ligation of the left gastric arterie (n=11, dark grey) or with complete ligation of the paraoesophageal bundle (n=10, light grey). Data are shown as mean values ± SEM. Post-hoc differences between the 3 groups are indicated (# = p<0.001 and † = p<0.05).

Figure 2

a Average daily energy intake (Group 1) over 60 days for sham-operated ad libitum fed rats (n=7, white column) and for gastric bypass rats (n=14, black column). Data are shown as mean values ± SEM. b Average daily energy intake (Group 2) over 60 days for sham-operated ad libitum fed rats (n=8, white column) and for gastric bypass rats (n=8, black column). Data are shown as mean values ± SEM (*** = p<0.001). c Average daily energy intake (Group 3) over 75 days for sham-operated ad libitum fed rats (n=10, white column) and for gastric bypass rats with selective ligation of the left gastric arterie (n=11, dark grey) or with complete ligation of the paraoesophageal bundle (n=10, light grey). Data are shown as mean values ± SEM. Post-hoc differences between the 3 groups are indicated (# = p<0.001 and † = p<0.05).

Figure 3

a Body weight change in group 1 for the gastric bypass (-o-) (n=14) and sham-operated rats (-■-)(n=7). Data are shown as mean values ± SEM (* = p<0.05). b Body weight change in group 2 for the gastric bypass (-o-) (n=8) and sham-operated rats (-■-)(n=8). Data are shown as mean values ± SEM (* = p<0.05). c Body weight change in group 3 for the gastric bypass rats with complete ligation of the paraoesophageal neurovascular bundle (-o-) (n=10) and gastric bypass rats with selective ligation of the left gastric arterie (-●-) (n=11) and sham-operated rats (-■-)(n=10). Data are shown as mean values ± SEM (* = p<0.05 for sham vs. bypass; # = p<0.05 for bypass with complete ligation vs. bypass with selective ligation).

Figure 3

a Body weight change in group 1 for the gastric bypass (-o-) (n=14) and sham-operated rats (-■-)(n=7). Data are shown as mean values ± SEM (* = p<0.05). b Body weight change in group 2 for the gastric bypass (-o-) (n=8) and sham-operated rats (-■-)(n=8). Data are shown as mean values ± SEM (* = p<0.05). c Body weight change in group 3 for the gastric bypass rats with complete ligation of the paraoesophageal neurovascular bundle (-o-) (n=10) and gastric bypass rats with selective ligation of the left gastric arterie (-●-) (n=11) and sham-operated rats (-■-)(n=10). Data are shown as mean values ± SEM (* = p<0.05 for sham vs. bypass; # = p<0.05 for bypass with complete ligation vs. bypass with selective ligation).

Figure 3

a Body weight change in group 1 for the gastric bypass (-o-) (n=14) and sham-operated rats (-■-)(n=7). Data are shown as mean values ± SEM (* = p<0.05). b Body weight change in group 2 for the gastric bypass (-o-) (n=8) and sham-operated rats (-■-)(n=8). Data are shown as mean values ± SEM (* = p<0.05). c Body weight change in group 3 for the gastric bypass rats with complete ligation of the paraoesophageal neurovascular bundle (-o-) (n=10) and gastric bypass rats with selective ligation of the left gastric arterie (-●-) (n=11) and sham-operated rats (-■-)(n=10). Data are shown as mean values ± SEM (* = p<0.05 for sham vs. bypass; # = p<0.05 for bypass with complete ligation vs. bypass with selective ligation).