Regulation of Enterocyte Brush Border Membrane Primary Na-Absorptive Transporters in Human Intestinal Organoid-Derived Monolayers.

In the small intestine, sodium (Na) absorption occurs primarily via two apical transporters, Na-hydrogen exchanger 3 (NHE3) and Na-glucose cotransporter 1 (SGLT1). The two primary Na-absorptive pathways were previously shown to compensatorily regulate each other in rabbit and rat intestinal epithelial cells. However, whether NHE3 and SGLT1 regulate one another in normal human enterocytes is unknown, mainly due to a lack of appropriate experimental models. To investigate this, we generated 2D enterocyte monolayers from human jejunal 3D organoids and used small interfering RNAs (siRNAs) to knock down NHE3 or SGLT1. Molecular and uptake studies were performed to determine the effects on NHE3 and SGLT1 expression and activity. Knockdown of NHE3 by siRNA in enterocyte monolayers was verified by qPCR and Western blot analysis and resulted in reduced NHE3 activity. However, in NHE3 siRNA-transfected cells, SGLT1 activity was significantly increased. siRNA knockdown of SGLT1 was confirmed by qPCR and Western blot analysis and resulted in reduced SGLT1 activity. However, in SGLT1 siRNA-transfected cells, NHE3 activity was significantly increased. These results demonstrate for the first time the functionality of siRNA in patient-derived organoid monolayers. Furthermore, they show that the two primary Na absorptive pathways in human enterocytes reciprocally regulate one another.

Molecular mechanisms underlying glucose-dependent insulinotropic polypeptide secretion in human duodenal organoids.

AIMS/HYPOTHESIS: Glucose-dependent insulinotropic polypeptide (GIP) is an incretin hormone secreted by enteroendocrine K cells in the proximal small intestine. This study aimed to explore the function of human K cells at the molecular and cellular levels. METHODS: CRISPR-Cas9 homology-directed repair was used to insert transgenes encoding a yellow fluorescent protein (Venus) or an Epac-based cAMP sensor (Epac-S-H187) in the GIP locus in human duodenal-derived organoids. Fluorescently labelled K cells were purified by FACS for RNA-seq and peptidomic analysis. GIP reporter organoids were employed for GIP secretion assays, live-cell imaging of Ca2+ using Fura-2 and cAMP using Epac-S-H187, and basic electrophysiological characterisation. The G protein-coupled receptor genes GPR142 and CASR were knocked out to evaluate roles in amino acid sensing. RESULTS: RNA-seq of human duodenal K cells revealed enrichment of several G protein-coupled receptors involved in nutrient sensing, including FFAR1, GPBAR1, GPR119, CASR and GPR142. Glucose induced action potential firing and cytosolic Ca2+ elevation and caused a 1.8-fold increase in GIP secretion, which was inhibited by the sodium glucose co-transporter 1/2 (SGLT1/2) blocker sotagliflozin. Activation of the long-chain fatty acid receptor free fatty acid receptor 1 (FFAR1) induced a 2.7-fold increase in GIP secretion, while tryptophan and phenylalanine stimulated secretion by 2.8- and 2.1-fold, respectively. While CASR knockout blunted intracellular Ca2+ responses, a CASR/GPR142 double knockout was needed to reduce GIP secretory responses to aromatic amino acids. CONCLUSIONS/INTERPRETATION: The newly generated human organoid K cell model enables transcriptomic and functional characterisation of nutrient-sensing pathways involved in human GIP secretion. Both calcium-sensing receptor (CASR) and G protein-coupled receptor 142 (GPR142) contribute to protein-stimulated GIP secretion. This model will be further used to identify potential targets for modulation of native GIP secretion in diabetes and obesity.

The Impact of SGLT1 Inhibition on Frailty and Sarcopenia: A Mediation Mendelian Randomization Study.

BACKGROUND: Although pharmacological effects of SGLT2 inhibitors on the development of frailty and sarcopenia were known, the role of SGLT1 remained less clear. The present study investigated the possible effect of SGLT1 inhibition on these conditions and explored potential mediators. METHODS: A two-sample Mendelian randomization (MR) analysis was performed to assess the effect of SGLT1 inhibition on frailty index (FI) and low grip strength in individuals aged 60 years and older using both the FNIH and EWGSOP criteria. Subsequently, a two-step MR analysis was conducted to investigate the mediating role of insulin resistance phenotype and identify potential mediators of the effect of SGLT1 inhibition on the FI and low grip strength from 1558 plasma proteins and 1352 metabolites. RESULTS: Genetically predicted SGLT1 inhibition was associated with decreased FI (ß: -0.290 [95% CI: -0.399, -0.181]) and reduced risk of low grip strength in individuals aged 60 years and older under both FNIH (ß: -0.796 [95% CI: -1.216, -0.376]) and EWGSOP criteria (ß: -0.287 [95% CI: -0.532, -0.041]). The two-step MR analysis demonstrated the role of insulin resistance phenotype in mediating SGTL1 inhibition on alleviating frailty (mediation proportion = 19.56% [95% CI: 8.42%, 30.70%]). After screening, 24 proteins and 16 metabolites were identified as mediators of the impact of SGLT1 inhibition on FI. Additionally, 13 proteins and 16 metabolites were found to mediate the effect of SGLT1 inhibition on low grip strength according to FNIH criteria while 22 proteins and 6 metabolites were shown to mediate the impact of SGLT1 inhibition on low grip strength under EWGSOP criteria. CONCLUSIONS: SGLT1 inhibition potentially mitigated frailty and sarcopenia through several biological mediators, shedding new light for therapeutic intervention.

Meta-analysis of sotagliflozin, a dual sodium-glucose-cotransporter 1/2 inhibitor, for heart failure in type 2 diabetes.

Sodium-glucose co-transporters (SGLTs) mediate sodium and glucose transport across cell membranes. SGLT2 inhibitors have a recognized place within heart failure (HF) guidelines. We evaluated the effect of sotagliflozin on HF and cardiovascular outcomes in participants with type 2 diabetes. Scopus, Medline, Embase and Central were searched from inception until 2 June 2023. Randomized controlled trials evaluating sotagliflozin in type 2 diabetes participants and reporting HF events were selected. Major adverse cardiovascular events (MACE) and systolic blood pressure were evaluated. The Cochrane risk of bias tool (RoB 2.0) was used. Pooled mean difference (MD), relative risk (RR), 95% confidence intervals and the number needed to treat (NNT) were estimated (PROSPERO: CRD42023432732). We selected nine studies (n = 15 320 participants: n = 8040 intervention and n = 7280 control). The median follow-up was 13.4 months (Q1 = 13, Q3 = 21). One study recruited participants with HF at baseline. After a follow-up of >52 weeks, sotagliflozin significantly reduced the risk of HF [n = 8 studies; RR = 0.66 (0.64, 0.69)], stroke [n = 6 studies; RR = 0.75 (0.58, 0.97)] and MACE [n = 8 studies; RR = 0.73 (0.66, 0.81)]. The NNT was 20 and 26 for HF and MACE, respectively. Sotagliflozin lowered systolic blood pressure [n = 7; MD = -2.38 mmHg (-2.79, -1.97)]. No dose-dependent effect was identified for HF [200 mg: RR = 0.38 (0.16, 0.89), 400 mg: RR = 0.57 (0.39, 0.85), P-value = 0.22]. The high risk of bias was a limitation of this review. Sotagliflozin reduced HF and cardiovascular events in type 2 diabetes participants. Research exploring its effects in HF and comparisons with SGLT2 inhibitors is warranted to determine if dual SGLT inhibition surpasses selective inhibition.

Effects of Sotagliflozin on Health Status in Patients With Worsening Heart Failure: Results From SOLOIST-WHF.

BACKGROUND: Sodium-glucose cotransporter 2 (SGLT2) inhibitors improve health status in heart failure (HF) across the left ejection fraction ejection spectrum. However, the effects of SGLT1 and SGLT2 inhibition on health status are unknown. OBJECTIVES: These prespecified analyses of the SOLOIST-WHF (Effect of Sotagliflozin on Cardiovascular Events in Patients with Type 2 Diabetes Post Worsening Heart Failure) trial examined the effects of sotagliflozin vs placebo on HF-related health status. METHODS: SOLOIST-WHF randomized patients hospitalized or recently discharged after a worsening HF episode to receive sotagliflozin or placebo. The primary endpoint was total number of HF hospitalizations, urgent HF visits, and cardiovascular death. Kansas City Cardiomyopathy Questionnaire-12 (KCCQ-12) score was a prespecified secondary endpoint. This analysis evaluated change in the KCCQ-12 score from baseline to month 4. RESULTS: Of 1,222 patients randomized, 1,113 (91%) had complete KCCQ-12 data at baseline and 4 months. The baseline KCCQ-12 score was low overall (median: 41.7; Q1-Q3: 27.1-58.3) and improved by 4 months in both groups. Sotagliflozin vs placebo reduced the risk of the primary endpoint consistently across KCCQ-12 tertiles (Ptrend = 0.54). Sotagliflozin-treated patients vs those receiving placebo experienced modest improvement in KCCQ-12 at 4 months (adjusted mean change: 4.1 points; 95% CI: 1.3-7.0 points; P = 0.005). KCCQ-12 improvements were consistent across prespecified subgroups, including left ventricular ejection fraction <50% or ≥50%. More patients receiving sotagliflozin vs those receiving placebo had at least small (≥5 points) improvements in KCCQ-12 at 4 months (OR: 1.38; 95% CI: 1.06-1.80; P = 0.017). CONCLUSIONS: Sotagliflozin improved symptoms, physical limitations, and quality of life within 4 months after worsening HF, with consistent benefits across baseline demographic and clinical characteristics. (Effect of Sotagliflozin on Cardiovascular Events in Participants With Type 2 Diabetes Post Worsening Heart Failure [SOLOIST-WHF]; NCT03521934).

Mechanical regulation of lipid and sugar absorption by Piezo1 in enterocytes.

Obesity is primarily caused by excessive intake as well as absorption of sugar and lipid. Postprandial surge in distention pressure and intestinal motility accelerates the absorption of nutrients. The response of intestinal epithelial cells to mechanical stimulation is not fully understood. Piezo1, a mechanosensitive ion channel, is widely expressed throughout the digestive tract. However, its function in intestinal nutrient absorption is not yet clear. In our study, excessive lipid deposition was observed in the duodenum of obese patients, while duodenal Piezo1-CaMKK2-AMPKα was decreased when compared to normal-weight individuals. Under high-fat diet condition, the Piezo1 iKO mice exhibited abnormally elevated sugar and lipid absorption as well as severe lipid deposition in the duodenum and liver. These phenotypes were mainly caused by the inhibition of duodenal CaMKK2-AMPKα and the upregulation of SGLT1 and DGAT2. In contrast, Yoda1, a Piezo1 agonist, was found to reduce intestinal lipid absorption in diet induced obese mice. Overexpression of Piezo1, stretch and Yoda1 inhibited lipid accumulation and the expression of DGAT2 and SGLT1, whereas knockdown of Piezo1 stimulated lipid accumulation and DGAT2 in Caco-2 cells. Our study reveals a previously unexplored mechanical regulation of nutrient absorption in intestinal epithelial cells, which may shed new light on the therapy of obesity.

Recent Progress and Perspectives in Sodium-Glucose Co-transporter 1/2 Inhibitors.

Sodium-Glucose Co-transporter-1/2 (SGLT1/2) inhibitors (also called glifozins) are a class of glucose-decreasing drugs in adults with Type 2 Diabetes (T2D). SGLT2 inhibitors diminish sodium and glucose reabsorption in the renal proximal convoluted tubule. Recent clinical trials have revealed that SGLT2 inhibitors might be beneficial for treating diseases other than diabetes, including chronic renal disease and Heart Failure (HF). Currently, SGLT2 inhibitors are recommended not only for the glycemic management of T2D but also for cardiovascular protection. SGLT2 inhibitors have become one of the foundational drugs for HF with reduced Ejection Fraction (HFrEF) treatment and the first medications with proven prognostic benefit in HF with preserved Ejection Fraction (HFpEF). At present, 11 SGLT1/2 inhibitors have been approved for clinical use in different countries. Beyond their anti-hyperglycemic effect, these inhibitors have shown clear cardio- and nephroprotective properties. A growing body of research studies suggests that SGLT1/2 inhibitors may provide potential clinical benefits in metabolic as well as oncological, hematological, and neurological disorders.

Biophysical Analysis of a Minimalistic Kidney Model Expressing SGLT1 Reveals Crosstalk between Luminal and Lateral Membranes and a Plausible Mechanism of Isosmotic Transport.

We extended our model of the S1 tubular segment to address the mechanisms by which SGLT1 interacts with lateral Na/K pumps and tight junctional complexes to generate isosmotic fluid reabsorption via tubular segment S3. The strategy applied allowed for simulation of laboratory experiments. Reproducing known experimental results constrained the range of acceptable model outputs and contributed to minimizing the free parameter space. (1) In experimental conditions, published Na and K concentrations of proximal kidney cells were found to deviate substantially from their normal physiological levels. Analysis of the mechanisms involved suggested insufficient oxygen supply as the cause and, indirectly, that a main function of the Na/H exchanger (NHE3) is to extrude protons stemming from mitochondrial energy metabolism. (2) The water path from the lumen to the peritubular space passed through aquaporins on the cell membrane and claudin-2 at paracellular tight junctions, with an additional contribution to water transport by the coupling of 1 glucose:2 Na:400 H2O in SGLT1. (3) A Na-uptake component passed through paracellular junctions via solvent drag in Na- and water-permeable claudin-2, thus bypassing the Na/K pump, in agreement with the findings of early studies. (4) Electrical crosstalk between apical rheogenic SGLT1 and lateral rheogenic Na/K pumps resulted in tight coupling of luminal glucose uptake and transepithelial water flow. (5) Isosmotic transport was achieved by Na-mediated ion recirculation at the peritubular membrane.

SGLT1 contributes to glucose-mediated exacerbation of ischemia-reperfusion injury in ex vivo rat heart.

Hyperglycaemia is common during acute coronary syndromes (ACS) irrespective of diabetic status and portends excess infarct size and mortality, but the mechanisms underlying this effect are poorly understood. We hypothesized that sodium/glucose linked transporter-1 (SGLT1) might contribute to the effect of high-glucose during ACS and examined this using an ex-vivo rodent heart model of ischaemia-reperfusion injury. Langendorff-perfused rat hearts were subjected to 35 min ischemia and 2 h reperfusion, with variable glucose and reciprocal mannitol given during reperfusion in the presence of pharmacological inhibitors of SGLT1. Myocardial SGLT1 expression was determined in rat by rtPCR, RNAscope and immunohistochemistry, as well as in human by single-cell transcriptomic analysis. High glucose in non-diabetic rat heart exacerbated reperfusion injury, significantly increasing infarct size from 45 ± 3 to 65 ± 4% at 11-22 mmol/L glucose, respectively (p < 0.01), an association absent in diabetic heart (32 ± 1-37 ± 5%, p = NS). Rat heart expressed SGLT1 RNA and protein in vascular endothelium and cardiomyocytes, with similar expression found in human myocardium by single-nucleus RNA-sequencing. Rat SGLT1 expression was significantly reduced in diabetic versus non-diabetic heart (0.608 ± 0.08 compared with 1.116 ± 0.13 probe/nuclei, p < 0.01). Pharmacological inhibitors phlorizin, canagliflozin or mizagliflozoin in non-diabetic heart revealed that blockade of SGLT1 but not SGLT2, abrogated glucose-mediated excess reperfusion injury. Elevated glucose is injurious to the rat heart during reperfusion, exacerbating myocardial infarction in non-diabetic heart, whereas the diabetic heart is resistant to raised glucose, a finding which may be explained by lower myocardial SGLT1 expression. SGLT1 is expressed in vascular endothelium and cardiomyocytes and inhibiting SGLT1 abrogates excess glucose-mediated infarction. These data highlight SGLT1 as a potential clinical translational target to improve morbidity/mortality outcomes in hyperglycemic ACS patients.

Electroacupuncture regulates glucose metabolism by inhibiting SGLT1 levels, inhibiting microglial polarization, and alleviating Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is a common central neurodegenerative disease in middle-aged and elderly people. The progressive degeneration and death of dopaminergic neurons leads to insufficient dopamine (DA) neurotransmitters. Acupuncture and moxibustion can alleviate the aging of neurons. Therefore, studying the neuroprotective effects of electroacupuncture (EA) in PD mice is particularly important. METHODS: Intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 20 mg/kg) was used to establish a PD mouse model, and lipopolysaccharide (LPS) was used to induce microglia polarization. Western blotting, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), Nissl staining and immunohistochemistry were used to detect neuronal apoptosis and injury, α-syn expression and microglial accumulation in PD mice. In addition, the levels of inflammatory factors were determined using enzyme-linked immunosorbent assay (ELISA). Flow cytometry was used to detect the Ca2+ content. The fluorescein isothiocyanate (FITC) labeling method was used to assess glucose uptake. A reagent kit was used to detect glucose and lactate levels. RESULTS: MPTP induced the selective loss of DA neurons in the SN of mice, altered Ca2+ homeostasis, and induced an inflammatory response. In addition, maintaining Ca2+ homeostasis depends on the activity of transient receptor potential channel 1 (TRPC1). EA therapy promotes TRPC1 expression, which has a negative regulatory effect on sodium-glucose cotransporter 1 (SGLT1). Under the action of EA, TRPC1 protein expression increased, Ca2+ concentrations increased, and the effect of SGLT1 was inhibited, thereby facilitating glucose metabolism, blocking the activation of the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway, restraining M1 polarization of microglia, and alleviating the PD process. CONCLUSION: EA promotes TRPC1/Ca2+ pathway activation, inhibits SGLT1-mediated regulation of glucose metabolism and PI3K/AKT pathway activation, inhibits microglial M1 polarization, and alleviates PD.

Red rice bran aqueous extract ameliorate diabetic status by inhibiting intestinal glucose transport in high fat diet/STZ-induced diabetic rats.

Red rice (Oryza sativa L.) consumption has grown recently, partly due to its potential health benefits in several disease prevention. The impact of red rice bran aqueous extract (RRBE) on intestinal glucose uptake and diabetes mellitus (DM) progression has not been thoroughly investigated. This study aimed to evaluate the effect of RRBE on ex vivo intestinal glucose absorption and its potential as an antihyperglycemic compound using a high-fat diet and streptozotocin (STZ)-induced diabetic rats. High-fat diet/STZ-induced diabetic rats were supplemented with either 1000 mg/kg body weight (BW) of RRBE, 70 mg/kg BW of metformin (Met), or a combination of RRBE and Met for 3 months. Plasma parameters, intestinal glucose transport, morphology, liver and soleus muscle glycogen accumulation were assessed. Treatment with RRBE, metformin, or combination markedly reversed hyperglycemia, hypertriglyceridemia, insulin resistance, and pancreatic morphology changes associated with T2DM. Correspondingly, all supplements effectively downregulated glucose transporters, resulting in a reduction of intestinal glucose transport-additionally, liver and soleus muscle glycogen accumulation was reduced in RRBE + Met treated group. Taken together, RRBE potentially suppressed intestinal glucose transporters' function and expression, reducing diabetic status.

Sympathetic Activation Promotes Sodium Glucose Co-Transporter-1 Protein Expression in Rodent Skeletal Muscle.

The hyperactivation of the sympathetic nervous system (SNS) is linked to obesity, hypertension, and type 2 diabetes, which are characterized by elevated norepinephrine (NE) levels. Previous research has shown increased sodium-dependent glucose cotransporter 1 (SGLT1) protein levels in kidneys of hypertensive rodents, prompting investigation into the expression of SGLT1 in various tissues, such as skeletal muscle. This study aimed to assess (i) whether skeletal muscle cells and tissue express SGLT1 and SGLT2 proteins; (ii) if NE increases SGLT1 levels in skeletal muscle cells, and (iii) whether the skeletal muscle of neurogenically hypertensive mice exhibits increased SGLT1 expression. We found that (i) skeletal muscle cells and tissue are a novel source of the SGLT2 protein and that (ii) NE significantly elevated SGLT1 levels in skeletal muscle cells. As SGLT2 inhibition (SGLT2i) with Empagliflozin increased SGLT1 levels, in vivo studies with the dual inhibitor SGLT1/2i, Sotagliflozin were warranted. The treatment of neurogenically hypertensive mice using Sotagliflozin significantly reduced blood pressure. Our findings suggest that SNS activity upregulates the therapeutic target, SGLT1, in skeletal muscle, potentially worsening cardiometabolic control. As clinical trial data suggest cardiorenal benefits from SGLT2i, future studies should aim to utilize SGLT1i by itself, which may offer a therapeutic strategy for conditions with heightened SNS activity, such as hypertension, diabetes, and obesity.

Xinbao Pill ameliorates heart failure via regulating the SGLT1/AMPK/PPARα axis to improve myocardial fatty acid energy metabolism.

BACKGROUND: Heart failure (HF) is characterized by a disorder of cardiomyocyte energy metabolism. Xinbao Pill (XBW), a traditional Chinese medicine formulation integrating "Liushen Pill" and "Shenfu Decoction," has been approved by China Food and Drug Administration for the treatment of HF for many years. The present study reveals a novel mechanism of XBW in HF through modulation of cardiac energy metabolism. METHODS: In vivo, XBW (60, 90, 120 mg/kg/d) and fenofibrate (100 mg/kg/d) were treated for six weeks in Sprague-Dawley rats that were stimulated by isoproterenol to induce HF. Cardiac function parameters were measured by echocardiography, and cardiac pathological changes were assessed using H&E, Masson, and WGA staining. In vitro, primary cultured neonatal rat cardiomyocytes (NRCMs) were induced by isoproterenol to investigate the effects of XBW on myocardial cell damage, mitochondrial function and fatty acid energy metabolism. The involvement of the SGLT1/AMPK/PPARα signalling axis was investigated. RESULTS: In both in vitro and in vivo models of ISO-induced HF, XBW significantly ameliorated cardiac hypertrophy cardiac fibrosis, and improved cardiac function. Significantly, XBW improved cardiac fatty acid metabolism and mitigated mitochondrial damage. Mechanistically, XBW effectively suppressed the expression of SGLT1 protein while upregulating the phosphorylation level of AMPK, ultimately facilitating the nuclear translocation of PPARα and enhancing its transcriptional activity. Knockdown of SGLT1 further enhanced cardiac energy metabolism by XBW, while overexpression of SGLT1 reversed the cardio-protective effect of XBW, highlighting that SGLT1 is probably a critical target of XBW in the regulation of cardiac fatty acid metabolism. CONCLUSIONS: XBW improves cardiac fatty acid energy metabolism to alleviate HF via SGLT1/AMPK/PPARα signalling axis.

Sodium-glucose cotransporter 1 promotes the biofunctions of perivascular preadipocytes mediated by Akt/mTOR/p70S6K signaling pathway.

The influence of SGLT-1 on perivascular preadipocytes (PVPACs) and vascular remodeling is not well understood. This study aimed to elucidate the role and mechanism of SGLT-1-mediated PVPACs bioactivity. PVPACs were cultured in vitro and applied ex vivo to the carotid arteries of mice using a lentivirus-based thermosensitive in situ gel (TISG). The groups were treated with Lv-SGLT1 (lentiviral vector, overexpression), Lv-siSGLT1 (RNA interference, knockdown), or specific signaling pathway inhibitors. Assays were conducted to assess changes in cell proliferation, apoptosis, glucose uptake, adipogenic differentiation, and vascular remodeling in the PVPACs. Protein expression was analyzed by Western blotting, immunocytochemistry, and/or immunohistochemistry. The methyl thiazolyl tetrazolium (MTT) assay and Hoechst 33342 staining indicated that SGLT-1 overexpression significantly promoted PVPACs proliferation and inhibited apoptosis in vitro. Conversely, SGLT-1 knockdown exerted the opposite effect. Oil Red O staining revealed that SGLT-1 overexpression facilitated adipogenic differentiation, while its inhibition mitigated these effects. 3H-labeled glucose uptake experiments demonstrated that SGLT-1 overexpression enhanced glucose uptake by PVPACs, whereas RNA interference-mediated SGLT-1 inhibition had no significant effect on glucose uptake. Moreover, RT-qPCR, Western blotting, and immunofluorescence analyses revealed that SGLT-1 overexpression upregulated FABP4 and VEGF-A levels and activated the Akt/mTOR/p70S6K signaling pathway, whereas SGLT-1 knockdown produced the opposite effects. In vivo studies corroborated these findings and indicated that SGLT-1 overexpression facilitated carotid artery remodeling. Our study demonstrates that SGLT-1 activation of the Akt/mTOR/p70S6K signaling pathway promotes PVPACs proliferation, adipogenesis, glucose uptake, glucolipid metabolism, and vascular remodeling.NEW & NOTEWORTHY SGLT-1 is expressed in PVPACs and can affect preadipocyte glucolipid metabolism and vascular remodeling. SGLT-1 promotes the biofunctions of PVPACs mediated by Akt/mTOR/p70S6K signaling pathway. Compared with caudal vein or intraperitoneal injection, the external application of lentivirus-based thermal gel around the carotid artery is an innovative attempt at vascular remodeling model, it may effectively avoid the transfection of lentiviral vector into the whole body of mice and the adverse effect on experimental results.

Exploring Bariatric Surgery's Impact on Weight Loss and Diabetes: Sodium and Glucose Receptor Modulation.

Sodium-glucose cotransporters (SGLT) and glucose transporters (GLUT) have been shown to influence diabetes management by modulating glucose uptake by the intestine. Therefore, alterations in gastrointestinal anatomy during bariatric surgery can change SGLT and GLUT receptor activity. These changes offer an additional mechanism for weight loss and may explain the differential impact of the various bariatric surgical procedures. This review examines the current literature on SGLT and GLUT receptors and their effects on weight loss through genetic studies, pharmacologic inhibition, and how SGLT/GLUT receptors impact surgical physiologic modulation. A better understanding of Type I sodium-glucose cotransport receptors (SGLT-1), GLUT-2, and GLUT-5 could provide insight for improved procedures and allow us to determine the best method to tailor operations to a patient's individual needs.

Canagliflozin inhibits PASMCs proliferation via regulating SGLT1/AMPK signaling and attenuates artery remodeling in MCT-induced pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) was a devastating disease characterized by artery remodeling, ultimately resulting in right heart failure. The aim of this study was to investigate the effects of canagliflozin (CANA), a sodium-glucose cotransporter 2 inhibitor (SGLT2i) with mild SGLT1 inhibitory effects, on rats with PAH, as well as its direct impact on pulmonary arterial smooth muscle cells (PASMCs). PAH rats were induced by injection of monocrotaline (MCT) (40 mg/kg), followed by four weeks of treatment with CANA (30 mg/kg/day) or saline alone. Pulmonary artery and right ventricular (RV) remodeling and dysfunction in PAH were alleviated with CANA, as assessed by echocardiography. Hemodynamic parameters and structural of pulmonary arteriole, including vascular wall thickness and wall area, were reduced by CANA. RV hypertrophy index, cardiomyocyte hypertrophy, and fibrosis were decreased with CANA treatment. PASMCs proliferation was inhibited by CANA under stimulation by platelet-derived growth factor (PDGF)-BB or hypoxia. Activation of AMP kinase (AMPK) was induced by CANA treatment in cultured PASMCs in a time- and concentration-dependent manner. These effects of CANA were attenuated when treatment with compound C, an AMPK inhibitor. Abundant expression of SGLT1 was observed in PASMCs and pulmonary arteries, while SGLT2 expression was undetectable. SGLT1 increased in response to PDGF-BB or hypoxia stimulation, while PASMCs proliferation was inhibited and beneficial effects of CANA were counteracted by knockdown of SGLT1. Our research demonstrated for the first time that CANA inhibited the proliferation of PASMCs by regulating SGLT1/AMPK signaling and thus exerted an anti-proliferative effect on MCT-induced PAH.

Impact of Drug-Mediated Inhibition of Intestinal Transporters on Nutrient and Endogenous Substrate Disposition an Afterthought?

A large percentage (~60%) of prescription drugs and new molecular entities are designed for oral delivery, which requires passage through a semi-impervious membrane bilayer in the gastrointestinal wall. Passage through this bilayer can be dependent on membrane transporters that regulate the absorption of nutrients or endogenous substrates. Several investigations have provided links between nutrient, endogenous substrate, or drug absorption and the activity of certain membrane transporters. This knowledge has been key in the development of new therapeutics that can alleviate various symptoms of select diseases, such as cholestasis and diabetes. Despite this progress, recent studies revealed potential clinical dangers of unintended altered nutrient or endogenous substrate disposition due to the drug-mediated disruption of intestinal transport activity. This review outlines reports of glucose, folate, thiamine, lactate, and bile acid (re)absorption changes and consequent adverse events as examples. Finally, the need to comprehensively expand research on intestinal transporter-mediated drug interactions to avoid the unwanted disruption of homeostasis and diminish therapeutic adverse events is highlighted.

Addition of low sodium does not increase sensitivity to glucose in wild-type mice, or lead to partial glucose taste detection in T1R3 knock-out mice.

The sodium glucose cotransporter 1 (SGLT1) has been proposed as a non-T1R glucosensor contributing to glucose taste. Studies have shown that the addition of NaCl at very weak concentrations to a glucose stimulus can enhance signaling in the gustatory nerves of mice and significantly lower glucose detection thresholds in humans. Here, we trained mice with (wild-type; WT) and without (knockout; KO) a functioning T1R3 subunit on a two-response operant detection task to differentially respond to the presence or absence of a taste stimulus immediately after sampling. After extensive training (∼40 sessions), KO mice were unable to reliably discriminate 2 M glucose+0.01 M NaCl from 0.01 M NaCl alone, but all WT mice could. We then tested WT mice on a descending array of glucose concentrations (2.0-0.03 M) with the addition of 0.01 M NaCl vs. 0.01 M NaCl alone. The concentration series was then repeated with glucose alone vs. water. We found no psychophysical evidence of a non-T1R taste transduction pathway involved in the detection of glucose. The addition of NaCl to glucose did not lower taste detection thresholds in WT mice, nor did it render the stimulus detectable to KO mice, even at 2 M. The proposed pathway must contribute to functions other than sensory-discriminative detection, at least when tested under these conditions. Detection thresholds were also derived for fructose and found to be 1/3 log10 lower than for glucose, but highly correlated (r = 0.88) between the two sugars, suggesting that sensitivity to these stimuli in this task was based on a similar neural process.

Beta-Hydroxybutyrate Levels and Risk of Diabetic Ketoacidosis in Adults with Type 1 Diabetes Treated with Sotagliflozin.

Introduction: Sodium glucose cotransporter inhibitors may increase beta-hydroxybutyrate (BHB) in insulin-requiring patients. We determined factors associated with BHB changes from baseline (ΔBHB) and diabetic ketoacidosis (DKA) in patients with type 1 diabetes (T1D) receiving sotagliflozin as an insulin adjunct. Research Design and Methods: This post hoc analysis compared ΔBHB levels in adults with T1D receiving sotagliflozin 400 mg or placebo for 6 months. We evaluated clinical and metabolic factors associated with ΔBHB and used logistic regression models to determine predictors associated with BHB values >0.6 and >1.5 mmol/L (inTandem3 population; N = 1402) or with DKA events in a pooled analysis (inTandem1-3; N = 2453). Results: From baseline (median, 0.13 mmol/L), median fasting BHB increased by 0.04 mmol/L (95% confidence interval, 0.03-0.05; P < 0.001) at 24 weeks with sotagliflozin versus placebo; 67% of patients had no or minimal changes in BHB over time. Factors associated with on-treatment BHB >0.6 or >1.5 mmol/L included baseline BHB and sotagliflozin use. Age, insulin pump use, sotagliflozin use, baseline BHB, and ΔBHB were significantly associated with DKA episodes. Independent of treatment, DKA risk increased by 18% with each 0.1-mmol/L increase in baseline BHB and by 8% with each 0.1-mmol/L increase from baseline. Conclusion: Incremental increases in baseline BHB and ΔBHB were associated with a higher DKA risk independent of treatment. Adding sotagliflozin to insulin increased median BHB over 24 weeks in patients with T1D and was associated with increased DKA events. These results highlight the importance of BHB testing and monitoring and individualizing patient education on DKA risk, mitigation, identification, and treatment.

Chinese bayberry (Myrica rubra Sieb. et Zucc.) leaves proanthocyanidins inhibit intestinal glucose transport in human Caco-2 cells.

Background: The hypoglycemic effects of Chinese bayberry leaves proanthocyanidins (BLPs) have been demonstrated. It is unclear, nevertheless, whether BLPs reduced postprandial blood glucose levels by regulating glucose uptake and glucose transport. Method: This study investigated the effect of BLPs (25, 50, and 100 µg/mL) on glucose uptake and glucose transport in human intestinal epithelial cells (Caco-2 cells). The uptake of 2-Deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl) amino]-D-glucose (2-NBDG) and disaccharidases activity in Caco-2 cells were measured. The glucose transport ability across the cell membrane was determined using the established Caco-2 monolayer model. The transcript and protein levels of key glucose transporters were analyzed using real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting, respectively. Results: The results showed that BLPs significantly decreased glucose uptake and disaccharidases activity (p < 0.05). Otherwise, BLPs treatment obviously inhibited glucose transport across the Caco-2 monolayer in both simulated-fast (5 mM glucose) and simulated-fed (25 mM glucose) conditions. It was attributed to the suppression of glucose transporter2 (GLUT2) and sodium-dependent glucose cotransporter 1 (SGLT1) by BLPs. BLPs were found to significantly downregulated the transcript level and protein expression of glucose transporters (p < 0.05). Meanwhile, the mRNA expression of phospholipase C (PLC) and protein kinase C (PKC) involved in the signaling pathway associated with glucose transport were decreased by BLPs. Conclusion: These results suggested that BLPs inhibited intestinal glucose transport via inhibiting the expression of glucose transporters. It indicated that BLPs could be potentially used as a functional food in the diet to modulate postprandial hyperglycemia.