Gastric Plication Improves Glycemia Partly by Restoring the Altered Expression of Aquaglyceroporins in Adipose Tissue and the Liver in Obese Rats
Leire Méndez-Giménez 1 2 , Sara Becerril 1 2 , Rafael Moncada 2 3 , Víctor Valentí 2 4 , Secundino Fernández 2 5 , Beatriz Ramírez 1 2 , Victoria Catalán 1 2 , Javier Gómez-Ambrosi 1 2 , Graça Soveral 6 , María M Malagón 2 7 , Carlos Diéguez 2 8 , Amaia Rodríguez 9 10 , Gema Frühbeck 1 2 11
Background: Gastric plication is a minimally invasive bariatric surgical procedure, where the greater curvature is plicated inside the gastric lumen. Our aims were to analyze the effectiveness of gastric plication on the resolution of obesity, impaired glucose tolerance, and fatty liver in an experimental model of diet-induced obesity (DIO) and to evaluate changes in glycerol metabolism, a key substrate for adiposity and gluconeogenesis, in adipose tissue and the liver.
Methods: Male Wistar DIO rats (n = 58) were subjected to surgical (sham operation and gastric plication) or dietary interventions [fed a normal diet (ND) or high-fat diet (HFD) or pair-fed to the amount of food eaten by gastric-plicated animals]. The expression of aquaglyceroporins (AQPs) in epididymal (EWAT) and subcutaneous (SCWAT) fat and the liver was analyzed by real-time PCR and Western blot.
Results: Gastric plication did not result in a significant weight loss in DIO rats, showing a modest reduction in whole-body adiposity and hepatic steatosis. However, gastric-plicated animals exhibited an improvement in basal glycemia and glucose clearance, without changes in hepatic gluconeogenic genes. DIO was associated with an increase in glycerol, higher AQP3 and AQP7 in EWAT and SCWAT, and a decrease in hepatic AQP9. Gastric plication downregulated AQP3 in both fat depots without changes in adipose AQP7 and hepatic AQP9.
Conclusion: Gastric plication results in a modest reduction in adiposity and hepatosteatosis but restores glycemia by downregulating AQP3, which entails lower efflux of glycerol from fat, lower plasma glycerol availability, and a reduced use of glycerol as a substrate for hepatic gluconeogenesis.