Administration, Oral ; Glucose Transporter Type 2 ; metabolism ; Humans ; Intestinal Absorption ; physiology ; Organic Anion Transporters ; metabolism ; Peptide Transporter 1 ; Pharmacokinetics ; Sodium-Glucose Transporter 1 ; metabolism ; Symporters ; metabolism

The management of type 2 diabetes mellitus should comprise healthy lifestyle modifications along with tailored pharmacologic treatment. Traditionally, the American Diabetes Association (ADA)'s Diabetes Management Guidelines have not prioritized specific anti-diabetic drugs over others with regard to cardiovascular disease (CVD) and mortality prevention. Recently, two novel anti-diabetic medications proved to be significantly protective against future CVD and mortality, regardless of the glycemic levels achieved in type 2 diabetic patients with pre-existing CVD. The 2018 ADA Guidelines recommend SGLT2 inhibitor and/or GLP-1 receptor agonist be used for type 2 diabetes patients with atherosclerotic CVD after metformin monotherapy failure. Considering the value of CVD protection in the management of diabetes mellitus, this minor guideline adjustment could have far-reaching implications.
Cardiovascular Diseases ; Diabetes Mellitus ; Diabetes Mellitus, Type 2 ; Glucagon-Like Peptide-1 Receptor ; Humans ; Life Style ; Metformin ; Mortality ; Sodium-Glucose Transporter 2

OBJECTIVETo reveal the effects and related mechanisms of chlorogenic acid (CGA) on intestinal glucose homeostasis.

METHODSForty male Sprague-Dawley rats were randomly and equally divided into four groups: normal chow (NC), high-fat diet (HFD), HFD with low-dose CGA (20 mg/kg, HFD-LC), and HFD with high-dose CGA (90 mg/kg, HFD-HC). The oral glucose tolerance test was performed, and fast serum insulin (FSI) was detected using an enzyme-linked immunosorbent assay. The mRNA expression levels of glucose transporters (Sglt-1 and Glut-2) and proglucagon (Plg) in different intestinal segments (the duodenum, jejunum, ileum, and colon) were analyzed using quantitative real-time polymerase chain reaction. SGLT-1 protein and the morphology of epithelial cells in the duodenum and jejunum was localized by using immunofluorescence.

RESULTSAt both doses, CGA ameliorated the HFD-induced body weight gain, maintained FSI, and increased postprandial 30-min glucagon-like peptide 1 secretion. High-dose CGA inhibited the HFD-induced elevation in Sglt-1 expression. Both CGA doses normalized the HFD-induced downregulation of Glut-2 and elevated the expression of Plg in all four intestinal segments.

CONCLUSIONAn HFD can cause a glucose metabolism disorder in the rat intestine and affect body glucose homeostasis. CGA can modify intestinal glucose metabolism by regulating the expression of intestinal glucose transporters and Plg, thereby controlling the levels of blood glucose and insulin to maintain glucose homeostasis.

Animals ; Chlorogenic Acid ; pharmacology ; Diet, High-Fat ; adverse effects ; Glucagon-Like Peptide 1 ; metabolism ; Glucose ; metabolism ; Glucose Tolerance Test ; Glucose Transporter Type 2 ; metabolism ; Homeostasis ; Insulin ; blood ; Intestines ; drug effects ; metabolism ; Male ; Proglucagon ; metabolism ; Random Allocation ; Rats, Sprague-Dawley ; Sodium-Glucose Transporter 1 ; metabolism ; Weight Gain ; drug effects

Sodium-glucose co-transporters are a family of glucose transporter found in the intestinal mucosa of the small intestine (SGLT-2) and the proximal tubule of the nephron (SGLT-1 and SGLT-2). They contribute to renal glucose reabsorption and most of renal glucose (about 90%) is reabsorbed by SGLT-2 located in the proximal renal tubule. Selectively inhibiting activity of SGLT-2 is an innovative therapeutic strategy for treatment of type 2 diabetes by enhancing urinary glucose excretion from the body. Therefore SGLT-2 inhibitors are considered to be potential antidiabetic drugs with an unique mechanism. This review will highlight some recent advances and structure-activity relationships in the discovery and development of SGLT-2 inhibitors including O-glycoside, C-glycoside, C, O-spiro glycoside and non glycosides.
Animals ; Benzhydryl Compounds ; chemical synthesis ; chemistry ; pharmacology ; Diabetes Mellitus, Type 2 ; drug therapy ; Glucosides ; chemical synthesis ; chemistry ; pharmacology ; Humans ; Hypoglycemic Agents ; chemical synthesis ; chemistry ; pharmacology ; Molecular Structure ; Monosaccharides ; chemical synthesis ; chemistry ; pharmacology ; Sodium-Glucose Transporter 1 ; metabolism ; Sodium-Glucose Transporter 2 ; antagonists & inhibitors ; metabolism ; Structure-Activity Relationship

OBJECTIVE: To analyze the clinical phenotype and variant of SLC2A1 gene in a Chinese pedigree affected with glucose transporter type 1 deficiency syndrome (GLUT1-DS). METHODS: Clinical data of a child who was treated due to delayed motor and language development and his family members were collected. DNA was extracted from peripheral blood samples and subjected to high-throughput medical exome sequencing. Candidate variant was verified by Sanger sequencing of his parents and sister. The genotype-phenotype correlation was explored. RESULTS: The child, his mother and sister had common manifestations such as delayed mental and motor development, poor exercise tolerance, easy fatigue and paroxysmal dystonia, but the difference was that the child and his mother had microcephaly and seizures, while his sister did not. A heterozygous missense SLC2A1 c.191T>C (p.L64P) variant was identified in all affected members, which was unreported previously. CONCLUSION The missense SLC2A1 c.191T>C (p.L64P) variant probably underlay the disease in the proband and his mother and sister. Variability of the clinical phenotypes has reflected the genetic and phenotypic diversity of GLUT1-DS. Detection of the novel variant has enriched the spectrum of GLUT1-DS mutations.
Carbohydrate Metabolism, Inborn Errors ; China ; Glucose Transporter Type 1/genetics* ; Humans ; Monosaccharide Transport Proteins/deficiency* ; Mutation ; Pedigree ; Phenotype

Objective To assess the efficiency and safety of a novel sodium-glucose co-transporter 2 (SGLT2) inhibitor-SGLT2 inhibitors, in combination with insulin for type 1 diabetes mellitus (T1DM). Methods We searched Medline, Embase, and the Cochrane Collaboration Library to identify the eligible studies published between January 2010 and July 2016 without restriction of language. The Food and Drug Administration (FDA) data and ClinicalTrials (http://www.clinicaltrials.gov) were also searched. The included studies met the following criteria: randomized controlled trials; T1DM patients aged between 18 and 65 years old; patients were treated with insulin plus SGLT2 inhibitors for more than 2 weeks; patients' glycosylated hemoglobin (HbA1c) levels were between 7% and 12%. The SGLT2 inhibitors group was treated with SGLT2 inhibitors plus insulin, and the placebo group received placebo plus insulin treatment. The outcomes should include one of the following items: fasting blood glucose, HbA1c, glycosuria, or adverse effects. Data were analyzed by two physicians independently. The risk of bias was evaluated by using the Cochrane Collaboration's Risk of Bias tool and heterogeneity among studies was assessed using Chi-square test. Random effect model was used to analyze the treatment effects with Revman 5.3.Results Three trials including 178 patients were enrolled. As compared to the placebo group, SGLT2 inhibitor absolutely decreased fasting blood glucose [mean differences (MD) -2.47 mmol/L, 95% confidence interval (CI) -3.65 to -1.28, P<0.001] and insulin dosage (standardized MD -0.75 U, 95%CI -1.17 to -0.33, P<0.001). SGLT2 inhibitors could also increase the excretion of urine glucose (MD 131.09 g/24 h, 95%CI 91.79 to 170.39, P<0.001). There were no significant differences in the incidences of hyperglycemia [odds ratio (OR) 1.82, 95%CI 0.63 to 5.29, P=0.27], urinary tract infection (OR 0.95, 95%CI 0.19 to 4.85, P=0.95), genital tract infection (OR 0.27, 95%CI 0.01 to 7.19, P=0.43), and diabetic ketoacidosis (OR 6.03, 95%CI 0.27 to 135.99, P=0.26) between the two groups.Conclusion SGLT2 inhibitors combined with insulin might be an efficient and safe treatment modality for T1DM patients.
Adolescent ; Adult ; Aged ; Blood Glucose ; metabolism ; Diabetes Mellitus, Type 1 ; blood ; drug therapy ; Drug Therapy, Combination ; methods ; Fasting ; blood ; Female ; Glycated Hemoglobin A ; metabolism ; Humans ; Hypoglycemic Agents ; adverse effects ; therapeutic use ; Insulin ; adverse effects ; therapeutic use ; Male ; Middle Aged ; Randomized Controlled Trials as Topic ; Sodium-Glucose Transporter 2 ; antagonists & inhibitors

OBJECTIVETo assess the relationship between the overexpression of facilitative glucose transporter-1 (Glut1) and fluorine-18 fluorodeoxyglucose (FDG) uptake in patients with primary lung squamous cell carcinoma.

METHODSFrom April 1999 to March 2001, 23 patients with lung squamous cell carcinoma were imaged using FDG positron emission tomography (PET) before surgery. Their maximum and mean standard uptake values (SUVmax and SUVmean) of tumor and SUV of the normal lung (SUVlung) were measured. The expression of Glut1 of all the 23 cases was analysed in paraffin sections using SP immunohistochemistry.

RESULTSAll the 23 tumors tested were Glut1 positive (69 +/- 18)% of tumor cell area was positive and staining intensity was 4.6 +/- 0.7. All tumors of the patients could be detected by FDG-PET. FDG uptake of tumor was higher than that of normal lung (P < 0.01). SUVmax, SUVmean and SUVlung were 8.33 +/- 4.14, 6.10 +/- 3.00 and 0.38 +/- 0.13 respectively. Correlations were found among Glut1 expression and FDG uptake and tumor size (P < 0.01).

CONCLUSIONS(1) Glut1 overexpression is universal in the lung squamous cell carcinoma. (2) SUV was higher in the lung squamous cell carcinoma than that of the normal lung tissue. (3) Glut1 expression and FDG uptake and tumor size appear to be correlated with each other in patients with lung squamous cell carcinoma.

Aged ; Aged, 80 and over ; Carcinoma, Squamous Cell ; metabolism ; Fluorodeoxyglucose F18 ; metabolism ; Glucose Transporter Type 1 ; Humans ; Immunohistochemistry ; Lung Neoplasms ; metabolism ; Male ; Middle Aged ; Monosaccharide Transport Proteins ; analysis

D-glucose is an essential fuel for metabolism in mammalian cells and the predominant fuel source for the brain. Transport of glucose across tissue barriers is mediated by stereospecific transporter proteins. Glut-1 is a major glucose transporter expressed on vascular endothelial cells comprising the blood brain barrier and is responsible for glucose entry into the brain. Impaired glucose transport across the blood brain barrier results in Glut-1 deficiency syndrome(DS). It is caused by haploinsufficiency of the blood brain barrier hexose carrier. Heterozygous mutations or hemizygosity of the GLUT-1 gene cause Glut-1 DS. It is characterized by infantile seizures refractory to anticonvulsants, developmental delay, acquired microcephaly, spasticity, ataxia, opsoclonus and other paroxysmal neurological phenomena, often occurring prior to meals. The diagnosis of Glut-1 DS is established in neurologically impaired patients with reduced cerebrospinal glucose concentration(hypoglycorrhachia) and lactate concentration in the absence of hypoglycemia. Decreased 3-O-methyl-D-glucose uptake in erythrocytes also supports the diagnosis of Glut-1 DS. Several treatment strategies have been pursued, none optimal, as it relates to the developmental encephalopahty associated with this clinical syndrome. Ketogenic diet has been effective in controlling seizures but has had little measurable effects on the associated cognitive impairments and behavioral disturbance. Current treatment is inadequate, and future studies should be directed at the mechanisms designed to upreglulate GLUT-1 expression, thereby increasing residual Glut-1 activity to 75 to 100%.
3-O-Methylglucose ; Anticonvulsants ; Ataxia ; Blood-Brain Barrier ; Brain ; Diagnosis ; Endothelial Cells ; Epilepsy ; Erythrocytes ; Glucose Transport Proteins, Facilitative* ; Glucose Transporter Type 1* ; Glucose* ; Haploinsufficiency ; Humans ; Hypoglycemia ; Ketogenic Diet ; Lactic Acid ; Meals ; Metabolism ; Microcephaly ; Muscle Spasticity ; Ocular Motility Disorders ; Seizures

Insulin stimulates glucose transport in muscle and fat cells by promoting the translocation of glucose transporter (GLUT4) to the cell surface. Phosphatidylinositide 3-kinase (PI3-kinase) has been implicated in this process. However, the involvement of protein kinase B (PKB)/Akt and PKC- zeta, those are known as the downstream target of PI3-kinase in regulation of GLUT4 translocation, is not known yet. An interesting possibility is that these protein kinases phosphorylate GLUT4 directly in this process. In the present study, PKB- alpha and PKC- zeta were added exogenously to GLUT4-containing vesicles purified from low density microsome (LDM) of the rat adipocytes by immunoadsorption and immunoprecipitation for direct phosphorylation of GLUT4. Interestingly GLUT4 was phosphorylated by PKC- zeta and its phosphorylation was increased in insulin stimulated state but GLUT4 was not phosphorylated by PKB- alpha. However, the GST-fusion proteins, GLUT4 C-terminal cytoplasmic domain (GLUT4C) and the entire major GLUT4 cytoplasmic domain corresponding to N-terminus, central loop and C-terminus in tandem (GLUT4NLC) were phosphorylated by both PKB- alpha and PKC- zeta. The immunoblots of PKC- zeta and PKB- alpha antibodies with GLUT4-containing vesicles preparation showed that PKC- zeta was co-localized with the vesicles but not PKB- alpha. From the above results, it is clear that PKC- zeta interacts with GLUT4-containing vesicles and it phosphorylates GLUT4 protein directly but PKB- alpha does not interact with GLUT4, suggesting that insulin-elicited signals that pass through PI3-kinase subsequently diverge into two independent pathways, an Akt pathway and a PKC- zeta pathway, and that later pathway contributes, at least in part, insulin stimulation of GLUT4 translocation in adipocytes via a direct GLUT4 phosphorylation.
Adipocytes* ; Animals ; Antibodies ; Cytoplasm ; Glucose ; Glucose Transport Proteins, Facilitative ; Glucose Transporter Type 4 ; Immunoprecipitation ; Insulin ; Microsomes ; Phosphatidylinositol 3-Kinases ; Phosphorylation* ; Protein Kinases ; Proto-Oncogene Proteins c-akt ; Rats*

The specific inhibition of angiotensin II action at AT(1) receptors by losartan has been shown to decrease peripheral insulin resistance in type 2 diabetic patients and animal models. We examined the effect of losartan on the expression of insulin receptor substrate 1 (IRS-1), protein kinase B (PKB) and glucose transporter 4 (GLUT4), as well as the phosphorylation status of IRS-1 and the association between IRS-1 and phosphatidylinositol (PI) 3-kinase in skeletal muscle from fat-fed and-streptozotocin (STZ)-treated rats, an animal model of type 2 diabetes mellitus. In addition, the effects of losartan on GLUT4 translocation in muscle cells and on insulin sensitivity were also evaluated. Muscle tissues were isolated from male losartan-treated and untreated normal or non-insulin-dependent diabetes mellitus (NIDDM) rats with a dose of 4 mg/kg per day for 6 weeks. Oral administration of losartan improved insulin sensitivity, which was determined by an oral glucose tolerance test (OGTT). In skeletal muscles, the protein levels of IRS-1, PKB and GLUT4 in NIDDM rats were not significantly different from those of the control rats, and they were not affected by losartan. The levels of IRS-1 tyrosine phosphorylation, PI 3-kinase activity associated with IRS-1 and PKB activation after stimulation with insulin in muscle tissue of NIDDM rats were significantly decreased (P<0.01) compared with those in the control rats, while they were not increased by losartan. Losartan had a major effect on GLUT4 translocation in myocytes, as it significantly increased (P<0.05) the insulin-induced amounts of GLUT4 in plasma membrane (PM) and T-tubules (TT) in myocytes from NIDDM rats. Consistent with these results, the plasma glucose level in losartan-treated NIDDM rats was decreased (P<0.05) compared with that in untreated NIDDM rats. Our results suggest that losartan may exert beneficial effects on insulin resistance by increasing the translocation of GLUT4 in muscle tissue, which is probably associated with a non-PI 3-kinase-dependent mechanism.
Animals ; Diabetes Mellitus, Experimental ; blood ; drug therapy ; Diabetes Mellitus, Type 2 ; blood ; drug therapy ; physiopathology ; Glucose Transporter Type 4 ; Insulin Receptor Substrate Proteins ; Insulin Resistance ; Losartan ; pharmacology ; therapeutic use ; Male ; Monosaccharide Transport Proteins ; biosynthesis ; genetics ; Muscle Proteins ; biosynthesis ; genetics ; Muscle, Skeletal ; metabolism ; Phosphoproteins ; biosynthesis ; genetics ; Protein-Serine-Threonine Kinases ; biosynthesis ; genetics ; Proto-Oncogene Proteins ; biosynthesis ; genetics ; Proto-Oncogene Proteins c-akt ; Rats ; Rats, Sprague-Dawley