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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.

Background: Aging and obesity are two conditions associated with increased risk of cardiovascular disease. Our aim was to analyze whether an advanced age affects the beneficial effects of sleeve gastrectomy on weight loss and blood pressure in an experimental model of diet-induced obesity (DIO)., Methods: Young (6-month-old) and old (18-month-old) male Wistar DIO rats (n = 101) were subjected to surgical (sham operation and sleeve gastrectomy) or dietary interventions (pair-fed to the amount of food eaten by sleeve gastrectomized animals). Systolic (SBP), diastolic (DBP), and mean (MBP) blood pressure values and heart rate (HR) were recorded in conscious, resting animals by non-invasive tail-cuff plethysmography before and 4 weeks after surgical or dietary interventions., Results: Aging was associated with higher (P < 0.05) body weight and subcutaneous and perirenal fat mass as well as mild cardiac hypertrophy. Sleeve gastrectomy induced a reduction in body weight, whole-body adiposity, and serum total ghrelin in both young and old DIO rats. The younger group achieved a higher excess weight loss than the older group (164 ± 60 vs. 82 ± 17 %, P < 0.05). A significant (P < 0.05) decrease in insulin resistance, SBP, DBP, MBP, and HR without changes in heart weight was observed after sleeve gastrectomy independently of age., Conclusion: Our results provide evidence for the effectiveness of sleeve gastrectomy without increased operative risk in body weight and blood pressure reduction even in aged animals via endocrine changes that go beyond the mere caloric restriction.

Background: Susceptibility to obesity is associated with a notable inter-individual variation. The aim of the present study was to compare the effectiveness of sleeve gastrectomy (SG) on weight loss and metabolic profile in obesity-prone (OP) rats vs animals that are non-susceptible to obesity (NSO)., Methods: Young male Wistar rats (n = 101) were put in a diet-induced obesity (DIO) programme with ad libitum access to a high-fed diet (HFD) during 12 months. Body weight and food intake were regularly registered. Thereafter, rats were ranked by final body weight to identify the obesity-prone (OP) (n = 13) and non-susceptible to obesity (NSO) (n = 14) animals. OP and NSO rats were submitted to surgical interventions (sham operation, SG and pair-fed to the amount of food eaten by sleeve-gastrectomized rats). Body weight, food intake, energy expenditure, body temperature, fat pads weight, and metabolic profiling were analysed 4 weeks after surgical or dietary interventions., Results: SG in both OP and NSO rats decreased body weight as compared to sham and pair-fed groups (P < 0.05), mainly due to reductions in subcutaneous and perirenal fat mass (P < 0.001). Total weight loss achieved in sleeve-gastrectomized OP and NSO rats was higher than that of pair-fed ones (P < 0.05), showing that the SG effect goes beyond caloric restriction. In this regard, sleeve-gastrectomized rats exhibited significantly (P < 0.05) increased basal rectal temperature together with upregulated brown adipose tissue Ucp-1 protein expression levels. A significant (P < 0.05) improvement in insulin sensitivity was also observed in both OP and NSO animals that underwent SG as compared with pair-fed counterparts., Conclusion: Our findings provide the first evidence that obesity-prone rats also benefit from surgery responding effectively to SG, as evidenced by the significant body weight reduction and the metabolic profile improvement.

Background: Glycerol constitutes an important metabolite for the control of lipid accumulation and glucose homeostasis. Our aim was to investigate the potential role of aquaglyceroporins, which are glycerol channels mediating glycerol efflux in adipocytes (AQP3 and AQP7) and glycerol influx (AQP9) in hepatocytes, in the improvement of adiposity and hepatic steatosis after sleeve gastrectomy in an experimental model of diet-induced obesity (DIO)., Methods: Male Wistar DIO rats (n = 161) were subjected to surgical (sham operation and sleeve gastrectomy) or dietary interventions [fed ad libitum a normal diet (ND) or a high-fat diet (HFD) or pair-fed to the amount of food eaten by sleeve-gastrectomized animals]. The tissue distribution and expression of AQPs in biopsies of epididymal (EWAT) and subcutaneous (SCWAT) white adipose tissue and liver were analyzed by real-time PCR, Western blot, and immunohistochemistry., Results: Four weeks after surgery, DIO rats undergoing sleeve gastrectomy showed a reduction in body weight, whole-body adiposity, and hepatic steatosis. DIO was associated with a tendency towards an increase in EWAT AQP3 and SCWAT AQP7 and a decrease in hepatic AQP9. Sleeve gastrectomy downregulated AQP7 in both fat depots and upregulated AQP3 in EWAT, without changing hepatic AQP9. Aqp7 transcript levels in EWAT and SCWAT were positively associated with adiposity and glycemia, while Aqp9 mRNA was negatively correlated with markers of hepatic steatosis and insulin resistance., Conclusion: Our results show, for the first time, that sleeve gastrectomy, a widely applied bariatric surgery procedure, restores the coordinated regulation of fat-specific AQP7 and liver-specific AQP9, thereby improving whole-body adiposity and hepatic steatosis.

Background: Sleeve gastrectomy (SG) constitutes an effective procedure for the treatment of morbid obesity. The aim of the present study was to establish in rats the effects of surgically induced weight loss on circulating concentrations and mRNA expression in adipose tissue and liver of osteopontin (OPN), a proinflammatory protein involved in the development of obesity., Methods: Eighty male diet-induced obese Wistar rats were subjected to surgical interventions [sham operation (SH), SG, or pair-fed to the amount of food eaten by SG animals] and dietary interventions [fed ad libitum with a normal chow diet (ND) or a high-fat diet (HFD)]. Body, epididymal adipose tissue (EWAT), and liver weights were determined. Circulating OPN concentrations and the transcript levels of Spp1 (OPN) in EWAT and liver were analyzed., Results: Rats undergoing SG showed decreased body weight (P < 0.001) and fat mass (P < 0.001) and greater excess weight loss (P < 0.001). The HFD significantly decreased serum OPN levels (P < 0.001). However, SG did not change serum OPN concentrations. OPN expression was dramatically increased in animals fed HFD (P < 0.001) in EWAT, but was unaffected by SG. The expression of OPN in the liver was not affected by HFD or SG., Conclusions: Circulating OPN levels decreased with HFD feeding remaining unaltered after SG. The expression of Spp1 in EWAT and liver was not modified by SG. The global improvement of metabolism after SG appears not to involve changes in serum OPN concentrations as well as in EWAT and liver expression in rats.

Background: Sleeve gastrectomy constitutes an effective surgical procedure for the treatment of morbid obesity. The aim of the present study was to establish the effects of sleeve gastrectomy and caloric restriction on weight loss and cardiovascular parameters in diet-induced obese (DIO) rats., Methods: Male Wistar DIO rats were subjected to surgical interventions (n = 30) (sham operation, sleeve gastrectomy, or pair-fed to the amount of food eaten by sleeve-gastrectomized animals and compared to lean control rats) or dietary interventions (n = 40) (fed ad libitum a normal diet (ND) or a high-fat diet or an ND with a caloric restriction of 25 %). Systolic blood pressure (SBP), diastolic blood pressure, and mean blood pressure values and heart rate (HR) were recorded in conscious, resting animals by noninvasive tail-cuff plethysmography before and 3 weeks after surgical or dietary interventions., Results: Both sleeve gastrectomy and caloric restriction induced a reduction in body weight, whole-body adiposity, and serum leptin together with an increased excess weight loss in DIO rats. Sleeve gastrectomy was further associated with an improvement in insulin resistance and the lipid profile, as well as with a reduction in serum ghrelin levels. A decrease in HR and heart weight was observed in caloric-restricted groups. Sleeve-gastrectomized rats not only exhibited a reduction in HR (∆HR = -45 ± 19 bpm) but also in SBP values (∆SBP = -22 ± 10 mmHg) compared to the DIO rats (∆SBP = 14 ± 8 mmHg)., Conclusion: Our findings provide evidence that the beneficial effects of sleeve gastrectomy on blood pressure values are beyond weight loss in rats with diet-induced obesity.

Background: Sleeve gastrectomy (SG) has been used as a multipurpose surgical procedure for the treatment of morbid obesity. The aim of the study was to analyze gastric morphology and histology at two different time points after SG in rats., Methods: Thirty-five male Wistar rats were fed ad libitum during 3 months on a high-fat diet to induce obesity. Subsequently, 25 diet-induced obese rats underwent either SG (n = 12) or a sham operation (n = 13). The remaining ten obese animals encompassed the nonoperated control group (Co). Four weeks postoperatively, 15 rats (n = 5 rats/experimental group) were sacrificed, while the remaining 20 rats were sacrificed after 16 weeks (animals/group; Co = 5, sham = 8, SG = 7) to compare the gastric morphological and histopathological changes over time. Body weight and food intake were regularly recorded., Results: For both time periods, the Co groups exhibited the highest body weight, while the rats undergoing the SG showed the lowest weight gain (P < 0.05). Initially, significant differences (P < 0.005) in food intake relative to body weight were observed between the Co rats and animals undergoing surgery, which disappeared thereafter. The actual total stomach size after both experimental periods in the SG group was similar to that of non- and sham-operated rats mainly due to a forestomach enlargement, which was more pronounced after 16 weeks. Traits of gastritis cystica profunda characterized by gastric foveolae elongation with hyperplasia and cystic dilatation of the glands were observed in the residual stomachs of the sleeve-gastrectomized rats. These findings were mostly observed after 16 weeks of performing the SG, although they were also detected occasionally following 4 weeks postoperatively. No intestinal metaplasia was observed., Conclusion: After SG gastric macro- and microscopic changes with functional implications in both the short and long term take place.

Background: Sleeve gastrectomy constitutes an effective surgical procedure for the treatment of morbid obesity in humans and rodents with diet-induced obesity. The aim of the present study was to establish the effects of sleeve gastrectomy on weight loss and cardiovascular parameters in genetically obese (fa/fa) Zucker rats., Methods: Eleven-week-old male obese (fa/fa) (n = 20) Zucker rats were assigned to three alternative procedures (sham operation, sleeve gastrectomy, or pair-fed to the amount of food eaten by sleeve-gastrectomized animals) and compared with lean Zucker (Fa/Fa) rats (n = 9). Systolic (SBP), diastolic (DBP), and mean (MBP) blood pressure values as well as heart rate (HR) were recorded in conscious, resting animals by non-invasive tail-cuff plethysmography before and 3 weeks after the surgical interventions., Results: Sleeve-gastrectomized rats experienced a reduction in body weight (P < 0.01), total adiposity amounts (P < 0.001), together with an increased excess weight loss (%EWL) (P < 0.05) compared with sham-operated and pair-fed animals 3 weeks after the surgical interventions. Rats with sleeve gastrectomy exhibited reduced (P < 0.01) blood pressure values (ΔSBP = -11 ± 8 mmHg; ΔDBP = -6 ± 4 mmHg; ΔMBP = -8 ± 6 mmHg) compared with the control group, but no changes were observed in HR (P = 0.560). Sham-operated and pair-fed groups did not alter their cardiovascular variables., Conclusions: Our findings provide evidence of the beneficial effects of sleeve gastrectomy on blood pressure values in addition to the weight loss in obese (fa/fa) Zucker rats independently of surgical trauma and food intake reduction.

Background: Sleeve gastrectomy (SG) has been used for the surgical treatment of morbid obesity as a first or definitive procedure with satisfactory results. The objective of this study in rats was to establish the effects of SG on weight loss depending on the post-surgical type of diet followed., Methods: Thirty male Wistar rats were fed ad libitum during 3 months on a high-fat diet (HFD) to induce obesity. After this first phase, rats were subdivided in three groups of ten rats each and underwent a sham intervention, an SG, or no surgery but were pair-fed to the amount of food eaten by the animals of the SG group. At this time point, half of the animals in each group continued to be fed on the HFD, while the other half was switched to a normal chow diet (ND). Thus, the following subgroups were established: sham-ND, sleeve-ND, pair-fed-ND as well as sham-HFD, sleeve-HFD, and pair-fed-HFD. Body weight and food intake were recorded daily for 4 weeks. The feed efficiency rate (FER) was determined from weekly weight gains and caloric consumption during this period., Results: Statistically significant (P < 0.05) differences in body weight were observed between the six experimental groups after 4 weeks of the interventions with rats in the sleeve-ND group experimenting the highest weight loss (-78.2 ± 10.3 g) and animals in the pair-fed-HFD group exhibiting the lowest weight reduction (-4.0 ± 0.1 g). Interestingly, the FER value of rats that underwent the SG and continued to be fed on a HFD was significantly (P < 0.05) lower than that of sham operated and pair-fed animals on the same diet., Conclusion: The positive effects of SG on weight reduction are observed in obese rats submitted to the intervention and subsequently following an ND or even an HFD.