Diabetes is a widespread, rapidly increasing metabolic disease that is driven by hyperglycemia. Early glycemic control is of primary importance to avoid vascular complications including development of retinal disorders leading to blindness, end-stage renal disease, and accelerated atherosclerosis with a higher risk of myocardial infarction, stroke and limb amputations. Even after hyperglycemia has been brought under control, "metabolic memory," a cluster of irreversible metabolic changes that allow diabetes to progress, may persist depending on the duration of hyperglycemia. Manipulation of bile acid (BA) receptors and the BA pool have been shown to be useful in establishing glycemic control in diabetes due to their ability to regulate energy metabolism by binding and activating nuclear transcription factors such as farnesoid X receptor (FXR) in liver and intestine as well as the G-protein coupled receptor, TGR5, in enteroendocrine cells and pancreatic β-cells. The downstream targets of BA activated FXR, FGF15/21, are also important for glucose/insulin homeostasis. In this review we will discuss the effect of BAs on glucose and lipid metabolism and explore recent research on establishing glycemic control in diabetes through the manipulation of BAs and their receptors in the liver, intestine and pancreas, alteration of the enterohepatic circulation, bariatric surgery and alignment of circadian rhythms.
Animals ; Bile Acids and Salts ; blood ; metabolism ; Blood Glucose ; drug effects ; metabolism ; Circadian Rhythm ; Diabetes Mellitus ; blood ; drug therapy ; metabolism ; Energy Metabolism ; Homeostasis ; Humans ; Hyperglycemia ; metabolism ; physiopathology ; Hypoglycemic Agents ; therapeutic use ; Intestinal Mucosa ; metabolism ; Intestines ; drug effects ; Lipid Metabolism ; Liver ; drug effects ; metabolism ; Receptors, Cytoplasmic and Nuclear ; metabolism ; Receptors, G-Protein-Coupled ; metabolism ; Signal Transduction

In order to clarify the potential role of calcium sensing receptor (CaSR), a typical G protein coupled receptor (GPCR), in hyperglacemia-induced macroangiopathy, experimental hyperglycemia models in vivo and in vitro were prepared. Firstly, SD rats were divided into control group (n=10) and diabetes group (n=10), and diabetic model was induced via high-fat diet feeding and streptozotocin (STZ, 30 mg/kg) injection. Hydroxyproline level, determined via Choramnie T oxidation method, in vessel wall in diabetic rats was 30% more than that in control group. The gene transcription and expression levels were detected by real-time PCR and Western blotting, respectively. Both of collagen I and III mRNA levels in diabetic aorta were nearly twice those in normal aorta. The cleaved caspase-3 and -9 were elevated 1.5 and 2.5 times respectively in diabetic vascular cells. As compared with controls, mRNA and protein levels of CaSR in aorta were increased by 3 and 1.5 times in diabetes group. The expression levels of Bax as well as pro-apoptotic kinases (phospho-p38 and phosphor-JNK) were also increased 2, 0.5 and 0.5 times respectively in diabetic rats. To further validate the involvement of CaSR in cell apoptosis and explore the potential mechanism, the endothelial cell line (human umbilical vascular endothelial cells, HUVECs) was stimulated with high concentration of glucose (33 mmol/L) to mimic hyperglycemia in vitro. Cell-based assays also showed that the CaSR level and key apoptotic proteins (cleaved caspase-3 and -9, Bax, phospho-p38 and phosphor-JNK) were elevated in response to stimulation, and inhibition of CaSR by using specific inhibitor (NPS-2143, 10 μmol/L) could protect cells against apoptosis. Our results demonstrated that CaSR might take important part in the development of diabetic macroangiopathy through promoting cell apoptosis induced by hyperglycemia.
Animals ; Diabetic Angiopathies ; physiopathology ; Human Umbilical Vein Endothelial Cells ; Humans ; Hyperglycemia ; physiopathology ; Rats ; Receptors, Calcium-Sensing ; physiology

Gap junctions play a critical role in electrical synchronization and exchange of small molecules between neighboring cells; connexins are a family of structurally related transmembrane proteins that assemble to form vertebrate gap junctions. Hyperglycemia changes the structure gap junction proteins and their expression, resulting in obstruction of neural regeneration, vascular function and wound healing, and also promoting vascular atherosclerosis. These pathogenic factors would cause diabetic foot ulcers. This article reviews the involvement of connexins in pathogenesis of diabetic foot.
Atherosclerosis ; Connexins ; metabolism ; Diabetic Foot ; pathology ; Gap Junctions ; metabolism ; Humans ; Hyperglycemia ; physiopathology ; Regeneration ; Wound Healing

OBJECTIVETo investigate the effect of hyperglycemia induced by different doses of strepzotozocin (STZ) on the liver, kidneys and eyes in rats.

METHODSFifty SD rats were divided equally into 5 groups to receive intraperitoneal injections with a single dose of STZ (40, 50, or 60 mg/kg), 3 doses of 25 mg/kg STZ (given at the interval of 24 h), or no treatment (blank control). The dynamic change of blood glucose was observed within 72 h after the first injection. Blood glucose was then monitored every 3 days and the general conditions of the rats were recorded. In the 9th week, fasting blood samples were collected for biochemical analysis and the pancreas, kidney, liver, and eye were examined for pathologies.

RESULTSWithin 72 h after STZ injection, blood glucose first slightly increased and then decreased and again increased to maintain a high level. Death occurred in rats receiving injections with 50 and 60 mg/kg STZ on the third day. In the surviving rats in the 4 STZ-injected groups, the success rate of modeling was 70%, 89%, 100%, and 100%, respectively. Blood glucose showed an inverse correlation with the body weight of the rats. Cataract was observed in the 10th week in rats injected with 40 mg/kg STZ and in the 8th week in the other groups. In the 9th week, the rats receiving 40 mg/kg STZ showed normal insulin, C-peptide, urea, UA, Cr, ALT, AST, TP, and ALB levels, but the rats in the other groups all showed variations in these biochemical indices, which corresponded to the pathological findings in the pancreas, kidneys, and liver.

CONCLUSIONSThree STZ doses of 25 mg/kg is optimal and efficient for inducing diabetes in rats with stable hyperglycemia. Both fasting and random blood glucose tests contribute to the evaluation of the complications of diabetes. The eyes are the most sensitive to hyperglycemia, followed by the kidneys and then by the liver.

Animals ; Blood Glucose ; Body Weight ; Diabetes Mellitus, Experimental ; physiopathology ; Eye ; physiopathology ; Hyperglycemia ; physiopathology ; Kidney ; physiopathology ; Liver ; physiopathology ; Pancreas ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Streptozocin

This study is to investigate the effects of a Chinese prescription (FF), compatibility of Rhodiola crenulata, Cordyceps militaris and Rheum palmatum, on nephropathy in type 1 diabetic rats induced by streptozocin. According to fasting blood glucose level, diabetic rats were divided into three groups: model group, insulin-treated group and FF-treated group. Parameters for evaluating the glucose & lipid metabolism and the renal function were monitored dynamically. Levels of oxidative stress were detected ten weeks later. The results show that FF could significantly decrease the level of serum glucose and lipid profiles, improve the renal functions by decreasing blood urea nitrogen, urine albumin excretion and urease activity; FF could also affect on oxidative stress. In conclusion, Chinese prescription FF could ameliorate hyperglycemia-mediated renal damage in type 1 diabetic rats. These effects may be related to its regulation on the metabolism of glucose and lipid, the microcirculation disturbance and the oxidative stress.
Animals ; Cordyceps ; chemistry ; Diabetic Nephropathies ; drug therapy ; metabolism ; physiopathology ; Drugs, Chinese Herbal ; administration & dosage ; Herb-Drug Interactions ; Humans ; Hyperglycemia ; drug therapy ; metabolism ; physiopathology ; Kidney ; drug effects ; injuries ; physiopathology ; Male ; Metabolic Syndrome ; drug therapy ; metabolism ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Rhodiola ; chemistry ; Rhus ; chemistry

BACKGROUNDPrenatal hyperglycaemia may increase metabolic syndrome susceptibility of the offspring. An underlying component of the development of these morbidities is hepatic gluconeogenic molecular dysfunction. We hypothesized that maternal hyperglycaemia will influence her offsprings hepatic peroxisome proliferator-activated receptor coactivator-1α (PGC-1α) expression, a key regulator of glucose production in hepatocytes.

METHODWe established maternal hyperglycaemia by streptozotocin injection to induce the maternal hyperglycaemic Wistar rat model. Offspring from the severe hyperglycemia group (SDO) and control group (CO) were monitored until 180 days after birth. Blood pressure, lipid metabolism indicators and insulin resistance (IR) were measured. Hepatic PGC-1α expression was analyzed by reverse transcription polymerase chain reaction and Western blotting. mRNA expression of two key enzymes in gluconeogenesis, glucose-6-phosphatase (G-6-Pase) and phosphoenolpyruvate carboxykinase (PEPCK), were analyzed and compared.

RESULTSIn the SDO group, PGC-1α expression at protein and mRNA levels were increased, so were expression of G-6-Pase and PEPCK (P < 0.05). The above effects were seen prior to the onset of IR.

CONCLUSIONThe hepatic gluconeogenic molecular dysfunction may contribute to the metabolic morbidities experienced by this population.

Animals ; Female ; Hyperglycemia ; chemically induced ; physiopathology ; Insulin Resistance ; physiology ; Liver ; metabolism ; Male ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; Peroxisome Proliferator-Activated Receptors ; metabolism ; Pregnancy ; Prenatal Exposure Delayed Effects ; RNA-Binding Proteins ; Rats ; Rats, Wistar ; Streptozocin ; toxicity ; Transcription Factors

Early diabetic nephropathy is characterized by glomerular hyperpermeability as a result of impaired glomerular filtration structure caused by hyperglycemia, glycated proteins or irreversible advanced glycosylation endproducts (AGE). To investigate the effect of ginseng total saponin (GTS) on the pathologic changes of podocyte ZO (zonula occludens)-1 protein and podocyte permeability induced by diabetic conditions, we cultured mouse podocytes under: 1) normal glucose (5 mM, = control); 2) high glucose (HG, 30 mM); 3) AGE-added; or 4) HG plus AGE-added conditions and treated with GTS. HG and AGE increased the dextran filtration of monolayered podocytes at early stage (2-8 hr) in permeability assay. In confocal imaging, ZO-1 colocalized with actin filaments and beta-catenin at cell contact areas, forming intercellular filtration gaps. However, these diabetic conditions suppressed ZO-1 immunostainings and disrupted the linearity of ZO-1. In Western blotting, diabetic conditions also decreased cellular ZO-1 protein levels at 6 hr and 24 hr. GTS improved such quantitative and qualitative changes. These findings imply that HG and AGE have an influence on the redistribution and amount of ZO-1 protein of podocytes thereby causing hyperpermeability at early stage, which can be reversed by GTS.
Actin Cytoskeleton/metabolism ; Animals ; Cell Line ; Diabetic Nephropathies/physiopathology ; Glomerular Filtration Rate ; Glucose/*pharmacology ; Glycosylation End Products, Advanced/*pharmacology ; Hyperglycemia/physiopathology ; Membrane Proteins/*metabolism ; Mice ; *Panax ; Permeability/drug effects ; Phosphoproteins/*metabolism ; Plant Preparations/*pharmacology ; Podocytes/drug effects/pathology/physiology ; Saponins/*pharmacology ; beta Catenin/metabolism

INTRODUCTIONRecent periodicals direct that reactive carbonyl compounds are formed due to existing oxidative stress in type 2 diabetes mellitus, which further nonenzymatically react with proteins and lipids to form irreversible advanced glycation end products (AGE) and advanced lipoxidation end products (ALE). In type 2 diabetes mellitus, insulin resistance plays a pivotal role in hyperglycaemia. In this study, we tried to fi nd the relation between insulin resistance and carbonyl stress.

MATERIALS AND METHODSForty-seven patients of type 2 diabetes mellitus (age 51 ± 5.06 years) were selected and fasting plasma glucose, serum insulin, total carbonyl compounds, HbA1c, thiobarbituric acid reacting substances (TBARS) and Trolox equivalent antioxidant capacity (TEAC) were estimated using standard protocols. Homeostatic model assessement of insulin resistance (HOMA-IR) was evaluated from fasting plasma glucose and serum insulin levels.

RESULTSWe found highly significant correlations of carbonyl compounds with HOMA-IR, fasting plasma glucose and glycated haemoglobin (HbA1c). Correlations of lipid peroxidation end product, TBARS were not so significant.

CONCLUSIONFindings from this study indicate that the level of carbonyl compounds can be a biomarker of insulin resistance in type 2 diabetes mellitus.

Blood Glucose ; metabolism ; Diabetes Mellitus, Type 2 ; metabolism ; physiopathology ; Female ; Glycation End Products, Advanced ; blood ; metabolism ; Homeostasis ; physiology ; Humans ; Hyperglycemia ; metabolism ; Insulin Resistance ; physiology ; Male ; Middle Aged ; Oxidative Stress ; physiology

OBJECTIVETo study the pattern of the alterations of blood glucose, insulin and insulin sensitivity after traumatic brain injury in rats, and verify the occurrence of insulin resistance after the injury.

METHODSBased on Feeney's model of brain injury, the blood glucose and insulin concentration of the dogs measured 30 min before and at 6, 12, 24, 48, 72 and 120 h after injury. BG60-120, GIR60-120, and insulin sensitivity index (ISI) reflecting the insulin sensitivity were measured at 6, 24, 48, and 72 hours following severe traumatic brain injury using euglycemic-hyperinsulinemic clamp.

RESULTSBoth the blood glucose and insulin concentration increased markedly in rats following moderate and severe brain injury. BG60-120 increased markedly, and GIR60-120 and ISI decreased significantly 6, 24, 48, and 72 h after severe brain trauma as compared with those of the sham operation group. Blood glucose concentration of rats following severe injury was positively correlated with insulin concentration and BG60-120 at the corresponding time points, but negatively with GIR60-120 and ISI.

CONCLUSIONBoth the blood glucose and insulin concentration increase markedly in rats following severe brain injury. Increased blood glucose even in the presence of high-level insulin is due to acute insulin resistance occurring after traumatic brain injury.

Animals ; Blood Glucose ; metabolism ; Brain Injuries ; blood ; complications ; physiopathology ; Hyperglycemia ; etiology ; Insulin ; blood ; Insulin Resistance ; Male ; Rats ; Rats, Wistar

BACKGROUNDHyperglycemia has been shown to be a powerful predictor of poor outcome after ST-segment elevation myocardial infarction (STEMI). This study aimed to evaluate the effect of admission glucose on microvascular flow after successful primary percutaneous coronary intervention (PCI) in patients with STEMI.

METHODSSuccessful primary PCI was performed in 267 patients with STEMI. The maximum ST elevation of single electrocardiogram (ECG) lead before and 60 minutes after PCI was measured, and patients were then divided into 3 groups according to the degree of ST-segment resolution (STR): absent (<30%), partial (30% to 70%) or complete (> or =70%).

RESULTSOf the 267 patients, 48 (18.0%) had absent STR, 137 (51.3%) experienced partial STR, and 82 (30.7%) had complete STR. The degree of STR decreased with increasing admission glucose levels (P=0.032), and patients with hyperglycemia (serum glucose level > or =11 mmol/L) were more likely to have absent STR (P=0.001). Moreover,hyperglycemia was an independent predictor of incomplete STR (odds ratio, 1.870; 95% confidence interval, 1.038 to 3.371, P=0.037).

CONCLUSIONSHyperglycemia on admission is associated with abnormal coronary microvascular reperfusion in patients with STEMI after successful primary PCI, which may contribute, at least in part, to the poor outcomes in these patients.

Adult ; Aged ; Angioplasty, Balloon, Coronary ; methods ; Electrocardiography ; Female ; Glucose ; metabolism ; Humans ; Hyperglycemia ; blood ; pathology ; physiopathology ; Male ; Middle Aged ; Myocardial Infarction ; blood ; physiopathology ; therapy ; Odds Ratio