The benchmark for assessing quality of long-term glycemic control and adjustment of therapy is currently glycated hemoglobin(Hb A1c). Despite its importance as an indicator for the development of diabeticcomplications...The benchmark for assessing quality of long-term glycemic control and adjustment of therapy is currently glycated hemoglobin(Hb A1c). Despite its importance as an indicator for the development of diabeticcomplications, recent studies have revealed that this metric has some limitations; it conveys a rather complex message, which has to be taken into consideration for diabetes screening and treatment. On the basis of recent clinical trials, the relationship between Hb A1 c and cardiovascular outcomes in long-standing diabetes has been called into question. It becomes obvious that other surrogate and biomarkers are needed to better predict cardiovascular diabetes complications and assess efficiency of therapy. Glycated albumin, fructosamin, and 1,5-anhydroglucitol have received growing interest as alternative markers of glycemic control. In addition to measures of hyperglycemia, advanced glucose monitoring methods became available. An indispensible adjunct to Hb A1 c in routine diabetes care is selfmonitoring of blood glucose. This monitoring method is now widely used, as it provides immediate feedback to patients on short-term changes, involving fasting, preprandial, and postprandial glucose levels. Beyond the traditional metrics, glycemic variability has been identified as a predictor of hypoglycemia, and it might also be implicated in the pathogenesis of vascular diabetes complications. Assessment of glycemic variability is thus important, but exact quantification requires frequently sampled glucose measurements. In order to optimize diabetes treatment, there is a need for both key metrics of glycemic control on a day-to-day basis and for more advanced, user-friendly monitoring methods. In addition to traditional discontinuous glucose testing, continuous glucose sensing has become a useful tool to reveal insufficient glycemic management. This new technology is particularly effective in patients with complicated diabetes and provides the opportunity to characterize glucose dynamics. Several continuous glucose moni展开更多
BACKGROUND Mesenchymal stem cells(MSCs)are a type of stem cells that possess relevant regenerative abilities and can be used to treat many chronic diseases.Diabetes mellitus(DM)is a frequently diagnosed chronic diseas...BACKGROUND Mesenchymal stem cells(MSCs)are a type of stem cells that possess relevant regenerative abilities and can be used to treat many chronic diseases.Diabetes mellitus(DM)is a frequently diagnosed chronic disease characterized by hyperglycemia which initiates many multisystem complications in the long-run.DM patients can benefit from MSCs transplantation to curb down the pathological consequences associated with hyperglycemia persistence and restore the function of damaged tissues.MSCs therapeutic outcomes are found to last for short period of time and ultimately these regenerative cells are eradicated and died in DM disease model.AIM To investigate the impact of high glucose or hyperglycemia on the cellular and molecular characteristics of MSCs.METHODS Human adipose tissue-derived MSCs(hAD-MSCs)were seeded in low(5.6 mmol/L of glucose)and high glucose(25 mmol/L of glucose)for 7 d.Cytotoxicity,viability,mitochondrial dynamics,and apoptosis were deplored using specific kits.Western blotting was performed to measure the protein expression of phosphatidylinositol 3-kinase(PI3K),TSC1,and mammalian target of rapamycin(mTOR)in these cells.RESULTS hAD-MSCs cultured in high glucose for 7 d demonstrated marked decrease in their viability,as shown by a significant increase in lactate dehydrogenase(P<0.01)and a significant decrease in Trypan blue(P<0.05)in these cells compared to low glucose control.Mitochondrial membrane potential,indicated by tetramethylrhodamine ethyl ester(TMRE)fluorescence intensity,and nicotinamide adenine dinucleotide(NAD+)/NADH ratio were significantly dropped(P<0.05 for TMRE and P<0.01 for NAD+/NADH)in high glucose exposed hAD-MSCs,indicating disturbed mitochondrial function.PI3K protein expression significantly decreased in high glucose culture MSCs(P<0.05 compared to low glucose)and it was coupled with significant upregulation in TSC1(P<0.05)and downregulation in mTOR protein expression(P<0.05).Mitochondrial complexes I,IV,and V were downregulated profoundly in high glucose(P<0.05 compared 展开更多
Human sodium-glucose cotransporter 2 (hSGLT2) is a membrane protein responsible for glucose reabsorption from the glomerular filtrate in the proximal tubule. Inhibition of hSGLT2 has been regarded as a brand new thera...Human sodium-glucose cotransporter 2 (hSGLT2) is a membrane protein responsible for glucose reabsorption from the glomerular filtrate in the proximal tubule. Inhibition of hSGLT2 has been regarded as a brand new therapeutic approach for the treatment of type 2 diabetes mellitus (T2DM) due to its non-insulin related characteristics with less side effects. Current commercially available hSGLT2 inhibitors are all C-glycoside inhibitors. Previous studies have reported that N-glycoside inhibitors have better potential to serve as new drugs due to their good metabolic stability. In addition, non-glycoside inhibitors have been shown to exhibit the capability to overcome the existing problems of current glycoside inhibitors, including low tissue permeability, poor stability and short serum half-time. Here, we aimed to discover novel N-glycoside and non-glycoside hSGLT2 inhibitors by a combination of several computational approaches. A ligand-based pharmacophore model was generated, well validated and subsequently utilized as a 3D query to identify novel hSGLT2 inhibitors from National Cancer Institute (NCI) and Traditional Chinese Medicine (TCM) databases. Finally, one N-glycoside (NSC679207) and one non-glycoside (TCM_Piperenol_A) hSGLT2 inhibitors were successfully identified, which were proven to exhibit excellent binding affinities, pharmacokinetic properties and less toxicity than the commercially available hSGLT2 inhibitor, canagliflozin, via molecular docking, ADMET prediction, molecular dynamics (MD) simulations and binding free energy calculations. All together, our results strongly suggest that these two compounds have great potential to serve as novel hSGLT2 inhibitors for the treatment of T2DM and their efficacies may be further examined by a series of in vitro and/or in vivo bioassays.展开更多
Because insulin released by the β-cells of pancreatic islets is the main regulator of glucose levels, the quantitative modeling of their glucose-stimulated insulin secretion is of obvious interest not only to improve...Because insulin released by the β-cells of pancreatic islets is the main regulator of glucose levels, the quantitative modeling of their glucose-stimulated insulin secretion is of obvious interest not only to improve our understanding of the processes involved, but also to allow better assessment of β -cell function in diabetic patients or islet transplant recipients as well as the development of improved artificial or bioartificial pancreas devices. We have recently developed a general, local concentrations-based multiphysics computational model of insulin secretion in avascular pancreatic islets that can be used to calculate insulin secretion for arbitrary geometries of cultured, perifused, transplanted, or encapsulated islets in response to various glucose profiles. Here, experimental results obtained from two different dynamic glucose-stimulated insulin release (GSIR) perifusion studies performed by us following standard procedures are compared to those calculated by the model. Such perifusion studies allow the quantitative assessment of insulin release kinetics under fully controllable experimental conditions of varying external concentrations of glucose, oxygen, or other compounds of interest, and can provide an informative assessment of islet quality and function. The time-profile of the insulin secretion calculated by the model was in good agree- ment with the experimental results obtained with isolated human islets. Detailed spatial distributions of glucose, oxygen, and insulin were calculated and are presented to provide a quantitative visualization of various important aspects of the insulin secretion dynamics in perifused islets.展开更多
文摘The benchmark for assessing quality of long-term glycemic control and adjustment of therapy is currently glycated hemoglobin(Hb A1c). Despite its importance as an indicator for the development of diabeticcomplications, recent studies have revealed that this metric has some limitations; it conveys a rather complex message, which has to be taken into consideration for diabetes screening and treatment. On the basis of recent clinical trials, the relationship between Hb A1 c and cardiovascular outcomes in long-standing diabetes has been called into question. It becomes obvious that other surrogate and biomarkers are needed to better predict cardiovascular diabetes complications and assess efficiency of therapy. Glycated albumin, fructosamin, and 1,5-anhydroglucitol have received growing interest as alternative markers of glycemic control. In addition to measures of hyperglycemia, advanced glucose monitoring methods became available. An indispensible adjunct to Hb A1 c in routine diabetes care is selfmonitoring of blood glucose. This monitoring method is now widely used, as it provides immediate feedback to patients on short-term changes, involving fasting, preprandial, and postprandial glucose levels. Beyond the traditional metrics, glycemic variability has been identified as a predictor of hypoglycemia, and it might also be implicated in the pathogenesis of vascular diabetes complications. Assessment of glycemic variability is thus important, but exact quantification requires frequently sampled glucose measurements. In order to optimize diabetes treatment, there is a need for both key metrics of glycemic control on a day-to-day basis and for more advanced, user-friendly monitoring methods. In addition to traditional discontinuous glucose testing, continuous glucose sensing has become a useful tool to reveal insufficient glycemic management. This new technology is particularly effective in patients with complicated diabetes and provides the opportunity to characterize glucose dynamics. Several continuous glucose moni
文摘BACKGROUND Mesenchymal stem cells(MSCs)are a type of stem cells that possess relevant regenerative abilities and can be used to treat many chronic diseases.Diabetes mellitus(DM)is a frequently diagnosed chronic disease characterized by hyperglycemia which initiates many multisystem complications in the long-run.DM patients can benefit from MSCs transplantation to curb down the pathological consequences associated with hyperglycemia persistence and restore the function of damaged tissues.MSCs therapeutic outcomes are found to last for short period of time and ultimately these regenerative cells are eradicated and died in DM disease model.AIM To investigate the impact of high glucose or hyperglycemia on the cellular and molecular characteristics of MSCs.METHODS Human adipose tissue-derived MSCs(hAD-MSCs)were seeded in low(5.6 mmol/L of glucose)and high glucose(25 mmol/L of glucose)for 7 d.Cytotoxicity,viability,mitochondrial dynamics,and apoptosis were deplored using specific kits.Western blotting was performed to measure the protein expression of phosphatidylinositol 3-kinase(PI3K),TSC1,and mammalian target of rapamycin(mTOR)in these cells.RESULTS hAD-MSCs cultured in high glucose for 7 d demonstrated marked decrease in their viability,as shown by a significant increase in lactate dehydrogenase(P<0.01)and a significant decrease in Trypan blue(P<0.05)in these cells compared to low glucose control.Mitochondrial membrane potential,indicated by tetramethylrhodamine ethyl ester(TMRE)fluorescence intensity,and nicotinamide adenine dinucleotide(NAD+)/NADH ratio were significantly dropped(P<0.05 for TMRE and P<0.01 for NAD+/NADH)in high glucose exposed hAD-MSCs,indicating disturbed mitochondrial function.PI3K protein expression significantly decreased in high glucose culture MSCs(P<0.05 compared to low glucose)and it was coupled with significant upregulation in TSC1(P<0.05)and downregulation in mTOR protein expression(P<0.05).Mitochondrial complexes I,IV,and V were downregulated profoundly in high glucose(P<0.05 compared
文摘Human sodium-glucose cotransporter 2 (hSGLT2) is a membrane protein responsible for glucose reabsorption from the glomerular filtrate in the proximal tubule. Inhibition of hSGLT2 has been regarded as a brand new therapeutic approach for the treatment of type 2 diabetes mellitus (T2DM) due to its non-insulin related characteristics with less side effects. Current commercially available hSGLT2 inhibitors are all C-glycoside inhibitors. Previous studies have reported that N-glycoside inhibitors have better potential to serve as new drugs due to their good metabolic stability. In addition, non-glycoside inhibitors have been shown to exhibit the capability to overcome the existing problems of current glycoside inhibitors, including low tissue permeability, poor stability and short serum half-time. Here, we aimed to discover novel N-glycoside and non-glycoside hSGLT2 inhibitors by a combination of several computational approaches. A ligand-based pharmacophore model was generated, well validated and subsequently utilized as a 3D query to identify novel hSGLT2 inhibitors from National Cancer Institute (NCI) and Traditional Chinese Medicine (TCM) databases. Finally, one N-glycoside (NSC679207) and one non-glycoside (TCM_Piperenol_A) hSGLT2 inhibitors were successfully identified, which were proven to exhibit excellent binding affinities, pharmacokinetic properties and less toxicity than the commercially available hSGLT2 inhibitor, canagliflozin, via molecular docking, ADMET prediction, molecular dynamics (MD) simulations and binding free energy calculations. All together, our results strongly suggest that these two compounds have great potential to serve as novel hSGLT2 inhibitors for the treatment of T2DM and their efficacies may be further examined by a series of in vitro and/or in vivo bioassays.
文摘Because insulin released by the β-cells of pancreatic islets is the main regulator of glucose levels, the quantitative modeling of their glucose-stimulated insulin secretion is of obvious interest not only to improve our understanding of the processes involved, but also to allow better assessment of β -cell function in diabetic patients or islet transplant recipients as well as the development of improved artificial or bioartificial pancreas devices. We have recently developed a general, local concentrations-based multiphysics computational model of insulin secretion in avascular pancreatic islets that can be used to calculate insulin secretion for arbitrary geometries of cultured, perifused, transplanted, or encapsulated islets in response to various glucose profiles. Here, experimental results obtained from two different dynamic glucose-stimulated insulin release (GSIR) perifusion studies performed by us following standard procedures are compared to those calculated by the model. Such perifusion studies allow the quantitative assessment of insulin release kinetics under fully controllable experimental conditions of varying external concentrations of glucose, oxygen, or other compounds of interest, and can provide an informative assessment of islet quality and function. The time-profile of the insulin secretion calculated by the model was in good agree- ment with the experimental results obtained with isolated human islets. Detailed spatial distributions of glucose, oxygen, and insulin were calculated and are presented to provide a quantitative visualization of various important aspects of the insulin secretion dynamics in perifused islets.
