Figure 1.
Schematic illustration of generating the small gastric pouch (<5% of total gastric volume).
(A) Perigastric ligaments are ligated and cut to release the stomach. The arrow indicates the left gastric vessels and esophageal vessels. (B) The first branch of the left gastric vessels and the esophageal vessels are ligated and cut. (C) The left gastric vessels are bluntly separated from the cardia to make room for pouch operation without impairing the gastric blood supply. (D) and (E) A titanium clip is applied to the stomach with care not to impinge on the left gastric vessel bundles, and the stomach is transected right above the clip. (F) The small gastric pouch is anastomosed to the cut jejunum.
Figure 2.
Series of images depicting small pouch Roux-en-Y gastric bypass surgery in the mouse.
(A) The first 2 branches of the posterior left gastric vessels were ligated and cut. (B) The left gastric vessel bundles were separated from esophagus. The short arrow indicates the posterior left gastric vessels. The long arrow shows the gap between left gastric vessels and the cardia. (C) A titanium clip was applied to make the small gastric pouch (arrow). (D) The stomach was transected immediately above the clip, leaving the left gastric vessels intact (short arrow). The long arrow indicates the small gastric pouch. (E) The intact left gastric vessels (arrow point) guarantees normal blood supply of the stomach. (F) The arrow points to the completed gastrojejunostomy. (G) The arrow points to the completed jejunojejunostomy. (H) State of the gastric pouch at 3 weeks after surgery with the esophagus at the top (short arrow) and the small gastric pouch below (large arrow), clearly demonstrating that there was no expansion of the pouch after eating solid food for 3 weeks. (I) Picture showing the relative lengths of the Roux, biliopancreatic, and common limbs after RYGB surgery.
Figure 3.
Small pouch RYGB reduces fat mass and improves insulin tolerance in DIO mice.
(A) Body weight in gram. (B) Body weight change in percentage after RYGB or sham surgery. Note timing of insulin tolerance test (ITT) and cold response test, as well as food intake, body composition (NMR), and energy expenditure (EE) measurements indicated at the top. (C) Fat mass and lean mass at 8 weeks after RYGB or sham surgery. Note the significant reduction in fat mass but not lean mass after RYGB. (D) Insulin tolerance test showing significantly greater decrease of plasma glucose levels after administration of insulin (0.7 Unit/Kg, i.p.) in RYGB mice compared to sham-operated mice, at 8 weeks after surgery. Area under the curve (AUC) for 0–120 min is shown in the insert bar figure. Means ± SEM (RYGB n = 4, Sham n = 6). * p<0.05.
Figure 4.
Small pouch RYGB increases food intake and energy expenditure (EE) in DIO mice.
(A) Average daily high-fat diet intake measured over a period of 3 days at 5 weeks after RYGB or sham surgery. (B) Energy expenditure at 8 weeks after surgery as measured by indirect calorimetry normalized to total body mass. B. Pattern of energy expenditure over 24 h period. (C) Energy expenditure of RYGB and sham-operated mice measured over two consecutive days and shown as average rate per hour for the entire diurnal cycle and separately for day and night on the high fat diet. (D) Comparison of energy expenditure on high-fat diet (HFD, black bars) and on chow (white bars) in RYGB and sham-operated mice. Means ± SEM (RYGB n = 4, Sham n = 6). * p<0.05, based on the student t test or two-way ANOVA test.
Figure 5.
Effects of small pouch RYGB on respiratory exchange ratio (RER) and locomotor activity.
These tests were conducted at 9 weeks after surgery in mice fed a high-fat diet. (A) Diurnal pattern of RER. (B) Average RER for the entire diurnal cycle and separately for day and night. Note the significantly higher RER of RYGB mice during the dark period. (C) Diurnal pattern locomotor activity. (D) Average locomotor activity for the entire diurnal cycle and separately for day and night. Note the significantly higher activity of RYGB mice during the light period. Means ± SEM (RYGB n = 4, Sham n = 6). * p<0.05.
Figure 6.
Small pouch RYGB increases energy expenditure and respiratory exchange rate (RER).
These tests were conducted in DIO mice on chow diet. (A) Diurnal pattern of energy expenditure. (B) Average energy expenditure for the entire diurnal cycle and separately for day and night. The test was conducted in DIO mice at 9 weeks after RYGB or sham surgery and fed normal chow diet during testing. Note the significantly higher energy expenditure during both light and dark periods. (C) Diurnal pattern of RER. (D) Average RER for the entire diurnal cycle and separately for day and night. Note the significantly higher RER of RYGB mice for both day and night. Means ± SEM (RYGB n = 4, Sham n = 6). * p<0.05.
Figure 7.
Effects of RYGB on locomotor activity and response to cold exposure in mice fed chow diet.
(A) Diurnal pattern of locomotor activity. (B) Average locomotor activity for the entire diurnal cycle and separately for day and night. Note the significantly higher activity of RYGB mouse during the light period. (C) Cold exposure-induced change in body temperature of DIO mice at 6 weeks after RYGB or sham surgery and fed normal chow diet during testing. Area under the curve (AUC) is shown in the inset bar figure. Note that RYGB mice are less able to resist cold exposure compared with sham-operated mice. Means ± SEM (RYGB n = 4, Sham n = 6). * p<0.05.