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Bariatric surgery improves glucose homeostasis but the underlying mechanisms are not fully elucidated. Here, we show that the expression of sodium glucose cotransporter-2 (SGLT2/Slc5a2) is reduced in the kidney of lean and obese mice following vertical sleeve gastrectomy (VSG). Indicating an important contribution of altered cotransporter expression to the impact of surgery, inactivation of the SGLT2/Slc5a2 gene by CRISPR/Cas9 attenuated the effects of VSG, with glucose excursions following intraperitoneal injection lowered by ~30% in wild-type mice but by ~20% in SGLT2 null animals. The effects of the SGLT2 inhibitor dapaglifozin were similarly blunted by surgery. Unexpectedly, effects of dapaglifozin were still observed in SGLT2 null mice, consistent with the existence of metabolically beneficial off-target effects of SGLT2 inhibitors. Thus, we describe a new mechanism involved in mediating the glucose lowering effects of bariatric surgery.

Aims/hypothesis Although targeted in extrapancreatic tissues by several drugs used to treat type 2 diabetes, the role of AMP-activated protein kinase (AMPK) in the control of insulin secretion is still debatable. Previous studies have used pharmacological activators of limited selectivity and specificity, and none has examined in primary pancreatic beta cells the actions of the latest generation of highly potent and specific activators that act via the allosteric drug and metabolite (ADaM) site. Methods AMPK was activated acutely in islets isolated from C57BL6/J mice, and in an EndoC-βH3 cell line, using three structurally distinct ADaM site activators (991, PF-06409577 and RA089), with varying selectivity for β1- vs β2-containing complexes. Mouse lines expressing a gain-of-function mutation in the γ1 AMPK subunit (D316a) were generated to examine the effects of chronic AMPK stimulation in the whole body, or selectively in the beta cell. Results Acute (1.5 h) treatment of wild-type mouse islets with 991, PF-06409577 or RA089 robustly stimulated insulin secretion at high glucose concentrations (ppp2+ dynamics in response to 991 (AUC, ppppp Conclusions/interpretation AMPK activation exerts complex, time-dependent effects on insulin secretion. These observations should inform the design and future clinical use of AMPK modulators. Graphical abstract

AimsSpatially-organised increases in cytosolic Ca2+within pancreatic beta cells in the pancreatic islet underlie the stimulation of insulin secretion by high glucose. Recent data have revealed the existence of subpopulations of beta cells including “leaders” which initiate Ca2+waves. Whether leader cells possess unique molecular features, or localisation, is unknown.Main methodsHigh speed confocal Ca2+imaging was used to identify leader cells and connectivity analysis, running under MATLAB and Python, to identify highly connected “hub” cells. To explore transcriptomic differences between beta cell sub-groups, individual leaders or followers were labelled by photo-activation of the cryptic fluorescent protein PA-mCherry and subjected to single cell RNA sequencing (“Flash-Seq”).Key findingsDistinct Ca2+wave types were identified in individual islets, with leader cells present in 73 % (28 of 38 islets imaged). Scale-free, power law-adherent behaviour was also observed in 29% of islets, though “hub” cells in these islets did not overlap with leaders. Transcripts differentially expressed (295; padjvsfollower cells. Leader cells were also located significantly closer to delta cells in Euclidian space than were follower cells.SignificanceThe existence of both a discrete transcriptome and unique localisation implies a role for these features in defining the specialized function of leaders. Specifically, these data raise the possibility of altered signalling from delta cells towards somatostatin receptors present on leader cell cilia.

Mitochondrial glucose metabolism is essential for stimulated insulin release from pancreatic β-cells. Whether mitofusin gene expression, and hence, mitochondrial network integrity, is important for glucose or incretin signaling has not previously been explored. Here, we generated mice with β-cell-selective, adult-restricted deletion knock-out (dKO) of the mitofusin genes Mfn1 and Mfn2 (βMfn1/2 dKO). βMfn1/2-dKO mice displayed elevated fed and fasted glycemia and a more than fivefold decrease in plasma insulin. Mitochondrial length, glucose-induced polarization, ATP synthesis, and cytosolic and mitochondrial Ca2+ increases were all reduced in dKO islets. In contrast, oral glucose tolerance was more modestly affected in βMfn1/2-dKO mice, and glucagon-like peptide 1 or glucose-dependent insulinotropic peptide receptor agonists largely corrected defective glucose-stimulated insulin secretion through enhanced EPAC-dependent signaling. Correspondingly, cAMP increases in the cytosol, as measured with an Epac-camps-based sensor, were exaggerated in dKO mice. Mitochondrial fusion and fission cycles are thus essential in the β-cell to maintain normal glucose, but not incretin, sensing. These findings broaden our understanding of the roles of mitofusins in β-cells, the potential contributions of altered mitochondrial dynamics to diabetes development, and the impact of incretins on this process. G.A.R. was supported by a Wellcome Trust Senior Investigator Award (098424AIA) and Wellcome Trust Investigator Award (212625/Z/18/Z), Medical Research Council Programme grants (MR/R022259/1, MR/J0003042/ 1, MR/L020149/1), an Experimental Challenge Grant (DIVA, MR/L02036X/1), a Medical Research Council grant (MR/N00275X/1), and Diabetes UK grants (BDA/11/0004210, BDA/15/0005275, BDA16/0005485). I.L. was supported by a Diabetes UKD project grant (16/0005485). This project has received funding from the European Commission Innovative Medicines Initiative 2 Joint Undertaking, under grant agreement no. 115881 (RHAPSODY). This Joint Undertaking receives support from the European Union’s Horizon 2020 Research and Innovation Programme. This work is supported by the Swiss State Secretariat for Education, Research and Innovation (SERI), under contract no. 16.0097. A.T. was supported by Medical Research Council project grant MR/R010676/ 1. Intravital imaging was performed using resources and/or funding provided by National Institutes of Health grants R03 DK115990 (to A.K.L.), Human Islet Research Network UC4 DK104162 (to A.K.L., RRID:SCR_014393). BJ acknowledges support from the Academy of Medical Sciences, Society for Endocrinology, The British Society for Neuroendocrinology, the European Federation for the Study of Diabetes, an Engineering and Physical Sciences Research Council capital award, and the Medical Research Council (MR/R010676/1). S.A.S. was supported by the JDRF (CDA-2016-189, SRA-2018-539, COE-2019-861), the National Institutes of Health (R01 DK108921, U01 DK127747), and the U.S. Department of Veterans Affairs (I01 BX004444).

AIMS: Spatially-organized increases in cytosolic Ca2+ within pancreatic beta cells in the pancreatic islet underlie the stimulation of insulin secretion by high glucose. Recent data have revealed the existence of subpopulations of beta cells including "leaders" which initiate Ca2+ waves. Whether leader cells possess unique molecular features, or localisation, is unknown. MAIN METHODS: High speed confocal Ca2+ imaging was used to identify leader cells and connectivity analysis, running under MATLAB and Python, to identify highly connected "hub" cells. To explore transcriptomic differences between beta cell sub-groups, individual leaders or followers were labelled by photo-activation of the cryptic fluorescent protein PA-mCherry and subjected to single cell RNA sequencing ("Flash-Seq"). KEY FINDINGS: Distinct Ca2+ wave types were identified in individual islets, with leader cells present in 73 % (28 of 38 islets imaged). Scale-free, power law-adherent behaviour was also observed in 29 % of islets, though "hub" cells in these islets did not overlap with leaders. Transcripts differentially expressed (295; padj

Bariatric surgery improves both insulin sensitivity and secretion and can induce diabetes remission. However, the mechanisms and time courses of these changes, particularly the impact on β cell function, are difficult to monitor directly. In this study, we investigated the effect of Vertical Sleeve Gastrectomy (VSG) on β cell function in vivo by imaging Ca2+ dynamics in islets engrafted into the anterior eye chamber. Mirroring its clinical utility, VSG in mice results in significantly improved glucose tolerance, and enhanced insulin secretion. We reveal that these benefits are underpinned by augmented β cell function and coordinated activity across the islet. These effects involve changes in circulating GLP-1 levels which may act both directly and indirectly on the β cell, in the latter case through changes in body weight. Thus, bariatric surgery leads to time-dependent increases in β cell function and intra-islet connectivity which are likely to contribute to diabetes remission., Bariatric surgery procedures reduce weight and improve metabolic diseases. Here the authors investigate the effects of Vertical Sleeve Gastrectomy (VSG) on beta-cell function in mice using in vivo Ca2 + imaging and show that VSG increases beta-cell function and intra-islet connectivity.

Numerous studies have sought to decipher the genetic and other mechanisms contributing to β-cell loss and dysfunction in diabetes mellitus. However, we have yet to fully understand the etiology of the disease or to develop satisfactory treatments. Since the majority of diabetes susceptibility loci are mapped to non-coding regions within the genome, understanding the functions of non-coding RNAs in β-cell biology might provide crucial insights into the pathogenesis of type 1 (T1D) and type 2 (T2D) diabetes. During the past decade, numerous studies have indicated that long non-coding RNAs play important roles in the maintenance of β-cell mass and function. Indeed, lncRNAs have been shown to be involved in controlling β-cell proliferation during development and/or β-cell compensation in response to hyperglycaemia. LncRNAs such as TUG-1 and MEG3 play a role in both β-cell apoptosis and function, while others sensitize β-cells to apoptosis in response to stress signals. In addition, several long non-coding RNAs have been shown to regulate the expression of β-cell-enriched transcription factors in cis or in trans. In this review, we provide an overview of the roles of lncRNAs in maintaining β-function and mass, and discuss their relevance in the development of diabetes. Published version GAR was supported by a Wellcome Trust Investigator Award (212625/Z/18/Z), MRC Programme grants (MR/R022259/1, MR/J0003042/1, MR/L020149/1) and by Diabetes UK (BDA/11/0004210, BDA/15/0005275, BDA 16/0005485) project grants. This project has received funding from the European Union’s Horizon 2020 research and innovation programme via the Innovative Medicines Initiative 2 Joint Undertaking under grant agreement No 115881 (RHAPSODY). This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme and EFPIA.

BackgroundGlucocorticoids produced by the adrenal cortex are essential for the maintenance of metabolic homeostasis. Glucocorticoid activation is catalyzed by 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) and signalling is achieved through the glucocorticoid receptor (GR), a ligand-dependent transcription factor. Excess glucocorticoids are associated with insulin resistance and hyperglycaemia. A small number of studies have investigated the effects of bariatric surgery, a gastrointestinal procedure known to improve insulin sensitivity, on glucocorticoid metabolism, but the hypothesised mechanism is assumed to be via weight loss.AimTo investigate the effect of bariatric surgery on glucocorticoid metabolism in lean and obese mice.MethodsLean mice and HFD mice underwent Vertical Sleeve Gastrectomy (VSG) or sham surgery. Glucose and insulin tolerance tests were performed at four and ten weeks post operatively and circulating corticosterone was measured. Liver and adipose tissues were harvested from fed mice and 11β-HSD1 and GR levels were measured by quantitative RT-PCR or Western (immuno-) blotting, respectively.ResultsVSG did not cause excess weight loss in lean mice when compared to sham operated mice. However, both lean and HFD VSG mice displayed significantly improved glucose clearance and insulin sensitivity. Remarkably, VSG restores physiological corticosterone production in HFD mice and reduces11β-HSD1 levels at four and ten weeks post-surgery. Additionally, lean mice displayed significantly lowered mRNA levels of 11β-HSD1 in subcutaneous adipose tissue and GR in liver.ConclusionsBariatric surgery improves insulin sensitivity and reduces glucocorticoid activation at tissular level, under physiological and pathophysiological (obesity) conditions, irrespective of weight loss. The reduction of glucocorticoid exposure may represent an additional contribution to the health benefits of bariatric surgery. These findings point towards a physiologically relevant gut-adrenal axis.

Long non-coding RNAs (lncRNAs) are emerging as crucial regulators of {beta}-cell development and function. Consequently, the mis-expression of members of this group may contribute to the risk of type 2 diabetes (T2D). Here, we investigate roles for an antisense lncRNA expressed from the Pax6 locus (annotated as Pax6os1 in mice and PAX6-AS1 in humans) in {beta}-cell function. The transcription factor Pax6 is required for the development of pancreatic islets and maintenance of a fully differentiated {beta}-cell phenotype. Pax6os1/PAX6-AS1 expression was increased in pancreatic islets and {beta}-cell lines at high glucose concentrations, in islets from mice fed a high fat diet, and in those from patients with type 2 diabetes. Silencing or deletion of Pax6os1/PAX6-AS1 in MIN6 cells and EndoC-{beta}H1cells, respectively, upregulated {beta}-cell signature genes, including insulin. Moreover, shRNA-mediated silencing of PAX6-AS1 in human islets not only increased insulin mRNA, but also enhanced glucose-stimulated insulin secretion and calcium dynamics. In contrast, inactivation of Pax6os1 in mice was largely without effect on glucose homeostasis, though female Pax6os1 null mice on high fat diet (HFD) showed a tendency towards enhanced glucose clearance. Together, our results suggest that increased expression of PAX6-AS1 at high glucose levels may contribute to {beta}-cell dedifferentiation and failure in some forms of type 2 diabetes. Thus, targeting PAX6-AS1 may provide a promising strategy to enhance insulin secretion and improve glucose homeostasis in type 2 diabetes.

Background: Glucocorticoids (GC) produced by the adrenal cortex are essential for the maintenance of metabolic homeostasis. GC activation is catalyzed by 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) and signalling is achieved through the glucocorticoid receptor (GR), a ligand-dependent transcription factor. Excess glucocorticoids are associated with insulin resistance and hyperglycaemia. A small number of studies have investigated the effects of bariatric surgery, a gastrointestinal procedure known to improve insulin sensitivity, on glucocorticoid metabolism, but the hypothesised mechanism is assumed to be via weight loss. Aim: To investigate the effect of bariatric surgery on glucocorticoid metabolism in lean and obese mice. Methods: Fourteen lean mice and twelve HFD mice underwent Vertical Sleeve Gastrectomy (VSG) (n=7-8) or sham (n=5-6) surgery. Glucose and insulin tolerance tests were performed four weeks post operatively. Liver, gut and adipose tissue were harvested from fed mice and analysed using Quantitative real-time PCR (qRT-PCR) and Western Blot (WB). Results: VSG did not cause excess weight loss in lean mice when compared to sham operated mice (p=0.37). However, both lean and HFD VSG mice displayed significantly improved glucose and insulin tolerance (p Conclusions: Bariatric surgery improves insulin sensitivity and reduces glucocorticoid activation physiologically and in the obese state, irrespective of weight loss. The reduction in glucocorticoid signalling may represent an additional contribution to the health benefits of bariatric surgery. These findings point towards a physiologically-relevant gut-adrenal axis. Disclosure E. Akalestou: None. L. Lopez Noriega: None. I. Christakis: None. I. Leclerc: Consultant; Spouse/Partner; Sun Pharmaceutical Industries Ltd. Research Support; Spouse/Partner; Servier. G.A. Rutter: Consultant; Self; Sun Pharmaceutical Industries Ltd. Research Support; Self; Servier, Sun Pharmaceutical Industries Ltd. Funding Rosetrees Foundation (M825); British Society for Neuroendocrinology; Society for Endocrinology (19ES001); UK Wellcome Trust (212625/Z/18/Z); Medical Research Council UK (MR/R022259/1); European Union (115881)

Background: Bariatric surgery improves both insulin sensitivity and secretion in T2D. However, the impact on insulin secretion is difficult to monitor directly, requiring correction for insulin sensitivity. The degree to which surgery impacts β-cell function versus mass, and the time course over which these changes occur, also remain unclear. Aim: To investigate the effect of bariatric surgery on β-cell function in vivo, we imaged Ca2+ dynamics prospectively at the cellular level in islets engrafted into the anterior eye chamber. Methods: Ins1Cre mice were crossed to animals that express the genetic calcium indicator GCaMP6f behind a Lox PSTOPLoxP cassette. Isolated islets were engrafted into male C57BL6 mice maintained for 12 weeks on high fat/high sucrose diet (HFD). At pre- (-1) and post-operative weeks 4, 8 and 12, Vertical Sleeve Gastrectomy (VSG) (n=7) and sham (n=6) groups were anaesthetized, and islets imaged in the eye using a Nikon microscope equipped with a spinning disc, 488 nm laser and 20x/1.0 water immersion objective. Islets were scored as positive for wave activity when these were recurrent, had a defined origin and covered >75 % of the image plane. Glucose (3g/kg) tolerance and insulin secretion were assessed in parallel. Results: The VSG group demonstrated substantial weight loss during the first 4 weeks post-operatively but regained pre-operative weight by week 12. Nonetheless, VSG mice displayed significantly improved glucose tolerance and insulin secretion (p Conclusions: By imaging islet function in the eye in vivo we demonstrate that bariatric surgery leads to a time-dependent increase in glucose-induced Ca2+ dynamics of individual islets, likely to underlie increased insulin secretion. Disclosure E. Akalestou: None. K. Suba: None. L. Lopez Noriega: None. P.L. Chabosseau: None. I. Leclerc: Consultant; Spouse/Partner; Sun Pharmaceutical Industries Ltd. Research Support; Spouse/Partner; Servier. V. Salem: None. G.A. Rutter: Consultant; Self; Sun Pharmaceutical Industries Ltd. Research Support; Self; Servier, Sun Pharmaceutical Industries Ltd. Funding UK Wellcome Trust (212625/Z/18/Z); Rosetrees Trust (M825); UK Medical Research Council (MR/R022259/1); Harry Keen Diabetes UK Fellowship (BDA 15/0005317); European Union

Bariatric surgery improves both insulin sensitivity and secretion and can induce diabetes remission. However, the mechanisms and time courses of these changes, particularly the impact on β cell function, are difficult to monitor directly. In this study, we investigated the effect of Vertical Sleeve Gastrectomy (VSG) on β cell function in vivo by imaging Ca

Bariatric surgery improves both insulin sensitivity and secretion in type 2 diabetes. However, these changes are difficult to monitor directly and independently. In particular, the degree and the time course over which surgery impacts β cell function, versus mass, have been difficult to establish. In this study, we investigated the effect of bariatric surgery on β cell function in vivo by imaging Ca2+ dynamics prospectively and at the single cell level in islets engrafted into the anterior eye chamber. Islets expressing GCaMP6f selectively in the β cell were transplanted into obese male hyperglycaemic mice that were then subjected to either vertical sleeve gastrectomy (VSG) or sham surgery. Imaged in vivo in the eye, VSG improved coordinated Ca2+ activity, with 90% of islets observed exhibiting enhanced Ca2+ wave activity ten weeks post-surgery, while islet wave activity in sham animals fell to zero discernible coordinated islet Ca2+ activity at the same time point. Correspondingly, VSG mice displayed significantly improved glucose tolerance and insulin secretion. Circulating fasting levels of GLP-1 were also increased after surgery, potentially contributing to improved β cell performance. We thus demonstrate that bariatric surgery leads to time-dependent increases in individual β cell function and intra-islet connectivity, together driving increased insulin secretion and diabetes remission, in a weight-loss independent fashion.Significance StatementUsed widely to treat obesity, bariatric surgery also relieves the symptoms of type 2 diabetes. The mechanisms involved in diabetes remission are still contested, with increased insulin sensitivity and elevated insulin secretion from pancreatic β cells both implicated. Whilst the speed of remission – usually within a few days – argues for improvements in β cell function rather than increases in mass, a direct demonstration of changes at the level of individual β cells or islets has been elusive. Here, we combine vertical sleeve gastrectomy with intravital imaging of islets engrafted into the mouse anterior eye chamber to reveal that surgery causes a time-dependent improvement in glucose-induced Ca2+ dynamics and β cell - β cell connectivity, both of which likely underlie increased insulin release.

Aims/hypothesis Mitochondrial oxidative metabolism is central to glucose-stimulated insulin secretion (GSIS). Whether Ca2+ uptake into pancreatic beta cell mitochondria potentiates or antagonises this process is still a matter of debate. Although the mitochondrial Ca2+ importer (MCU) complex is thought to represent the main route for Ca2+ transport across the inner mitochondrial membrane, its role in beta cells has not previously been examined in vivo. Methods Here, we inactivated the pore-forming subunit of the MCU, encoded by Mcu, selectively in mouse beta cells using Ins1Cre-mediated recombination. Whole or dissociated pancreatic islets were isolated and used for live beta cell fluorescence imaging of cytosolic or mitochondrial Ca2+ concentration and ATP production in response to increasing glucose concentrations. Electrophysiological recordings were also performed on whole islets. Serum and blood samples were collected to examine oral and i.p. glucose tolerance. Results Glucose-stimulated mitochondrial Ca2+ accumulation (pppMcu-null (βMcu-KO) animals, in vitro, as compared with wild-type (WT) mice. Interestingly, cytosolic Ca2+ concentrations increased (pMcu-KO animals. βMcu-KO mice displayed impaired in vivo insulin secretion at 5 min (ppMcu-KO ( Conclusions/interpretation MCU is crucial for mitochondrial Ca2+ uptake in pancreatic beta cells and is required for normal GSIS. The apparent compensatory mechanisms that maintain glucose tolerance in βMcu-KO mice remain to be established.

Aims/hypothesis Mitochondrial oxidative metabolism is central to glucose-stimulated insulin secretion (GSIS). Whether Ca2+ uptake into pancreatic beta cell mitochondria potentiates or antagonises this process is still a matter of debate. Although the mitochondrial Ca2+ importer (MCU) complex is thought to represent the main route for Ca2+ transport across the inner mitochondrial membrane, its role in beta cells has not previously been examined in vivo. Methods Here, we inactivated the pore-forming subunit of the MCU, encoded by Mcu, selectively in mouse beta cells using Ins1Cre-mediated recombination. Whole or dissociated pancreatic islets were isolated and used for live beta cell fluorescence imaging of cytosolic or mitochondrial Ca2+ concentration and ATP production in response to increasing glucose concentrations. Electrophysiological recordings were also performed on whole islets. Serum and blood samples were collected to examine oral and i.p. glucose tolerance. Results Glucose-stimulated mitochondrial Ca2+ accumulation (p

Mitochondrial oxidative metabolism is central to glucose-stimulated insulin secretion (GSIS). Whether Ca2+uptake into pancreatic β-cell mitochondria potentiates or antagonises this process is still a matter of debate. Although the mitochondrial importer (MCU) complex is thought to represent the main route for Ca2+transport across the inner mitochondrial membrane, its role in β-cells has not previously been examinedin vivo. Here, we inactivated the pore-forming subunit MCUa (MCU) selectively in the β-cell in mice usingIns1Cre-mediated recombination. Glucose-stimulated mitochondrial Ca2+accumulation, ATP production and insulin secretion were strongly (pMCUnull animals (βMCU-KO)in vitro. Interestingly, cytosolic Ca2+concentrations increased (pin vivoinsulin secretion at 5 (p2+uptake in pancreatic β-cells and is required for normal GSIS. The apparent compensatory mechanisms which maintain glucose tolerance in βMCU-KO mice remain to be established.

BackgroundBariatric surgery has been established to improve insulin sensitivity and glucose clearance, but also increases insulin and glucagon secretion. Each of the above effects have also been observed following treatment with sodium glucose co-transporter 2 (SGLT2) inhibitors.AimTo determine whether there is an effect of bariatric surgery (Vertical Sleeve Gastrectomy; VSG) on renal SGLT2 expression in mice.MethodsEighteen lean mice underwent VSG (n=8) or sham (n=9) surgery. Glucose tolerance tests with or without treatment with the SGLT2 inhibitor dapagliflozin were performed four weeks post operatively, in order to assess if pharmacological SGLT2 inhibition has the same euglycemic effects after bariatric surgery. Kidneys were harvested from fed mice and SGLT2 expression was analysed using Quantitative reverse-transcription PCR and immunofluorescence.ResultsVSG mice displayed significantly improved glucose tolerance (AUC=103±6.8; AUC=66.6±2.9 in control and VSG mice, respectively; pConclusionsVertical sleeve gastrectomy in lean animals causes a significant inhibition of SGLT2 expression in the kidney cortex. These findings are in line with our previous results on the effects of Duodenal Jejunal Bypass in lean rats, and point towards a physiologically-relevant gut-kidney axis. SGLT2 inhibition may thus be an important mechanism through which bariatric surgery improves glucose tolerance in man.

Background: Bariatric surgery is known to improve glucose tolerance and weight loss, but can also cause a postprandial increase in renal glucose excretion following oral glucose tolerance test. Both effects have also been observed following treatment with sodium glucose co-transporter 2 (SGLT2) inhibitors. Aim: To investigate whether there is an effect of bariatric surgery (Vertical Sleeve Gastrectomy; VSG) on renal SGLT2 expression in mice. Methods: Fourteen lean mice underwent VSG (n=8) or sham (n=6) surgery. Glucose Tolerance tests with or without treatment with the SGLT2 inhibitor dapagliflozin were performed four weeks post operatively, in order to assess if exogenous SGLT2 inhibition has the same euglycemic effects as bariatric surgery. Kidneys were harvested from fed mice and analysed using Quantitative real-time PCR (qRT-PCR) and immunofluorescence. Results: VSG did not cause any weight loss when compared to sham operated mice (p=0.37, Mann-Whitney test). However, VSG mice displayed significantly improved glucose tolerance (AUC=103 ±6.8; AUC =66.6 ±2.9 in control and VSG mice, respectively; p0.05). In contrast, treatment of sham mice with dapagliflozin increased glucose tolerance, though to a lesser extent than VSG. Nevertheless, qPCR and immunofluorescence analysis on mouse kidneys demonstrated a significant lowering of SGLT2 expression at both the protein (n=5, p=0.0007) and mRNA (n=7, 0 Conclusions: Both gastric and intestinal surgery in lean animals causes a significant inhibition of SGLT2 in the kidney cortex. These findings are in line with our previous results on the effects of Duodenal Jejunal Bypass in lean rats, and point towards a physiologically-relevant gut-kidney axis. SGLT2 inhibition may thus be an important mechanism through which bariatric surgery improves glucose tolerance in man. Disclosure E. Akalestou: None. L. Lopez Noriega: None. P.L. Chabosseau: None. I. Leclerc: None. G.A. Rutter: Consultant; Self; Sun Pharma. Funding UK Wellcome Trust