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1.
J Comput Chem ; 43(32): 2121-2130, 2022 12 15.
Article in English | MEDLINE | ID: mdl-36190786

ABSTRACT

Novel agents to treat invasive fungal infections are urgently needed because the small number of established targets in pathogenic fungi makes the existing drug repertoire particularly vulnerable to the emergence of resistant strains. Recently, we reported that Candida albicans Bdf1, a bromodomain and extra-terminal domain (BET) bromodomain with paired acetyl-lysine (AcK) binding sites (BD1 and BD2) is essential for fungal cell growth and that an imidazopyridine (1) binds to BD2 with selectivity versus both BD1 and human BET bromodomains. Bromodomain binding pockets contain a conserved array of structural waters. Molecular dynamics simulations now reveal that one water molecule is less tightly bound to BD2 than to BD1, explaining the site selectivity of 1. This insight is useful in the performance of ligand docking studies to guide design of more effective Bdf1 inhibitors, as illustrated by the design of 10 new imidazopyridine BD2 ligands 1a-j, for which experimental binding and site selectivity data are presented.


Subject(s)
Candida albicans , Transcription Factors , Humans , Candida albicans/metabolism , Ligands , Transcription Factors/metabolism , Binding Sites
2.
Z Gastroenterol ; 60(9): 1314-1319, 2022 Sep.
Article in English | MEDLINE | ID: mdl-34768288

ABSTRACT

BACKGROUND: A disposable upper gastrointestinal endoscope can effectively decrease infectious outbreaks associated with endoscope reuse. In the present study, we aimed to evaluate the feasibility and safety of a disposable endoscope for upper gastrointestinal examination. METHODS: In a prospective, randomized trial, 144 upper endoscopic procedures were allocated to either the disposable endoscope group or the conventional endoscope group. The primary outcomes were rates of excellent and good image qualities and maneuverability satisfaction. The second outcome included procedure duration, endoscopic diagnosis, and adverse events. RESULTS: A total of 144 subjects were enrolled in the present analysis and prospectively randomized to 2 study groups. Finally, 70 and 69 subjects were enrolled in the novel disposable endoscope group and the conventional endoscope group, respectively, due to the schedule cancellation of 5 subjects. The baseline characteristics of the patients were similar in both groups. The excellent and good image quality rates and maneuverability satisfaction of the novel disposable endoscope were not inferior to the conventional endoscope (p = 0.99 and p = 0.99, respectively). Moreover, no significant between-group difference was observed in the endoscopic results and adverse events (p = 0.30 and p = 1, respectively). However, the procedure duration in the novel disposable endoscope was longer compared with the conventional endoscope (8.40 ± 4.28 min vs. 5.12 ± 2.65 min, p < 0.001). CONCLUSIONS: The novel disposable endoscope was as safe, effective, and maneuverable as a conventional endoscope. However, the novel disposable endoscope was associated with a longer procedure duration.


Subject(s)
Endoscopes , Upper Gastrointestinal Tract , Endoscopy, Gastrointestinal , Feasibility Studies , Humans , Prospective Studies
3.
Front Cardiovasc Med ; 8: 720922, 2021.
Article in English | MEDLINE | ID: mdl-34778392

ABSTRACT

Purpose: To investigate the impact of TSH levels using a more stringent cutoff of subclinical hypothyroidism (i.e., TSH > 2.5 mIU/L) on the short-term complications and long-term prognosis in patients who underwent heart transplantation (HTx). Methods: This is a retrospective study of consecutive patients with end-stage heart failure (HF) who underwent HTx. They were divided into three groups: thyroid-stimulating hormone (TSH) ≤ 2.50 mIU/L (L-TSH), 2.50 < TSH ≤ 4.91 mIU/L (M-TSH), and TSH > 4.91 mIU/L (H-TSH). The outcomes are all-cause death and cardiogenic death. Results: There are 63 (70%) males and 27 (30%) females. Nine (10%) patients died within 1 month after surgery, including five cardiogenic deaths. By 1 year, a total of 19 patients total were dead. The survival rate in the M-TSH group was significantly higher than that of the L-TSH group (P = 0.017). After adjusted by variables of sex, age, BMI, diabetes history, hypertension history, the multivariable Cox analysis showed that body mass index (HR = 0.804, 95%CI: 0.680-0.951, P = 0.011), and L-TSH (HR = 8.757, 95%CI: 1.786-42.948, P = 0.007 vs. M-TSH), and H-TSH (HR = 6.427, 95%CI: 1.137-36.327, P = 0.035 vs. M-TSH) were independently associated with all-cause death. The multivariable Cox analysis showed that body mass index (HR = 0.703, 95%CI: 0.564-0.878, P = 0.002), and L-TSH (HR = 17.717, 95%CI: 1.907-164.607, P = 0.011 vs. M-TSH) were independently associated with cardiogenic death. Conclusion: For patients with end-stage HF undergoing HTx, low and high baseline TSH levels are independently associated with 1-year all-cause death and low baseline TSH levels with cardiogenic death.

4.
Article in Chinese | MEDLINE | ID: mdl-34304484

ABSTRACT

Objective:To research the differences of sensory organization testing in maintaining postural stability between patients with type 2 diabetes mellitus and patients with peripheral vertigo using computerized posturography. Methods:Participants were divided into the control group (52 cases), the type 2 diabetes mellitus group (T2DM) (45 cases), and the peripheral vertigo group (PV) (47 cases). All participants were examined under six conditions by computerized posturography: The sensory organization test, a part of computerized dynamic posturography, was used to assess the abilities of vision, somatosensory and vestibular systems in maintaining postural stability. Results:The scores of statokinesiogram (SKG) of the T2DM group in condition 1 (standing on static platform with eye open), condition 4(standing on foam platform with eyes open) and condition 6(standing on foam platform with servo-controlled vision) were significantly greater than that in the vertigo group (P<0.01). The visual scores in the T2DM group were lower than those of the PV group(P<0.01) in the anteroposterior and lateral directions. Conclusion:Patients with type 2 diabetes and peripheral vertigo have a decreased ability to maintain balance in the upright position. Patients with type 2 diabetes have a poorer ability to maintain balance with visual systems than patients with peripheral vertigo.


Subject(s)
Diabetes Mellitus, Type 2 , Vestibular Diseases , Diabetes Mellitus, Type 2/complications , Humans , Postural Balance , Vertigo/diagnosis , Vestibular Diseases/diagnosis , Vision, Ocular
5.
Genomics ; 112(6): 4788-4795, 2020 11.
Article in English | MEDLINE | ID: mdl-32858135

ABSTRACT

Increasing evidence indicates that TP53 mutation impacts the patients' prognosis by regulating the gastric cancer (GC) immunophenotype. An immune prognostic signature (IPS) was constructed based on TP53 status. The effects of the IPS on the immune microenvironment of GC were analyzed. We also constructed a nomogram integrating the IPS and other clinical factors. An IPS was constructed in the TCGA cohort and validated in the meta-GEO cohort. TP53 mutation resulted in the downregulation of the immune response in GC. Concretely, high-risk patients were characterized by increased monocyte, macrophage M0 and T cell follicular helper infiltration; increased stromal score, ESTIMATE score and immune score; higher TIM3 and BTLA expression; and decreased dendritic cell and T cell CD4 memory-activated infiltration and tumor purity. The nomogram also showed good predictive performance. These results suggest that the IPS is an effective prognostic indicator for GC patients, which might provide a theoretical foundation for immunotherapy.


Subject(s)
Adenocarcinoma/immunology , Immunophenotyping , Stomach Neoplasms/immunology , Tumor Suppressor Protein p53/genetics , Adenocarcinoma/genetics , Humans , Mutation , Prognosis , Stomach Neoplasms/genetics
7.
Nat Commun ; 8: 15482, 2017 05 18.
Article in English | MEDLINE | ID: mdl-28516956

ABSTRACT

Invasive fungal infections cause significant morbidity and mortality among immunocompromised individuals, posing an urgent need for new antifungal therapeutic strategies. Here we investigate a chromatin-interacting module, the bromodomain (BD) from the BET family of proteins, as a potential antifungal target in Candida albicans, a major human fungal pathogen. We show that the BET protein Bdf1 is essential in C. albicans and that mutations inactivating its two BDs result in a loss of viability in vitro and decreased virulence in mice. We report small-molecule compounds that inhibit C. albicans Bdf1 with high selectivity over human BDs. Crystal structures of the Bdf1 BDs reveal binding modes for these inhibitors that are sterically incompatible with the human BET-binding pockets. Furthermore, we report a dibenzothiazepinone compound that phenocopies the effects of a Bdf1 BD-inactivating mutation on C. albicans viability. These findings establish BET inhibition as a promising antifungal therapeutic strategy and identify Bdf1 as an antifungal drug target that can be selectively inhibited without antagonizing human BET function.


Subject(s)
Antifungal Agents/pharmacology , Candida albicans/drug effects , Candidiasis/drug therapy , Fungal Proteins/antagonists & inhibitors , Molecular Targeted Therapy , Transcription Factors/antagonists & inhibitors , Amino Acid Sequence , Animals , Antifungal Agents/chemical synthesis , Azabicyclo Compounds/chemical synthesis , Azabicyclo Compounds/pharmacology , Azepines/pharmacology , Benzodiazepines/pharmacology , Binding Sites , Candida albicans/growth & development , Candida albicans/metabolism , Candida albicans/pathogenicity , Candidiasis/microbiology , Crystallography, X-Ray , Fungal Proteins/chemistry , Fungal Proteins/genetics , Gene Expression , Humans , Mice , Models, Molecular , Protein Binding , Protein Interaction Domains and Motifs , Protein Structure, Secondary , Pyridines/chemical synthesis , Pyridines/pharmacology , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Sequence Alignment , Sequence Homology, Amino Acid , Species Specificity , Transcription Factors/chemistry , Transcription Factors/genetics , Triazoles/pharmacology
8.
Article in Chinese | MEDLINE | ID: mdl-27197450

ABSTRACT

OBJECTIVE: Evaluation and analyze the characteristics of balance function in patients with type 2 diabetes, and to find out the importance of proprioception, vision and vestibular in postural control. METHOD: All subjects were divided into two groups, 37 normal individuals, 33 patients with type 2 diabetes mellitus. All were assessed by computerized posturography under six upright stance.conditions: including standing on the firm surface and foam with eyes open and closed. RESULT: (1) On anteroposterior,the scores of proprioception, vision and vestibular were 93.96 ± 7.95, 80.22 ± 16.24, 70.87 ± 20.99, the normal were 98.00 ± 2.18, 91.44 ± 6.01, 80.44 ± 7.81. There were significances between diabetes mellitus group and normal control group (P < 0.05) respectively. (2) On lateral, the scores of vision and vestibular were 80.39 ± 12.60, 73.96 ± 16.04, and the normal were 92.11 ± 4.50, 83.18 ± 9.45. There were significances with P < 0.05 between diabetes mellitus group and normal control group. However, there was no obvious difference in proprioception scores between the two groups. (3) The limit of stability of normal group were (176.47 ± 44.13) mm²; diabetic group was (143.13 ± 62.30) mm². There was statistical significance between the group with P < 0.05. (In diabetic patients, there was no significant difference between the no dizziness group and the dizziness group of the scores of proprioceptive, visual, vestibular as well as stable limits, P > 0.05. CONCLUSION: The balance function of patients with type 2 diabetes decreased. It is the main characteristic that the vision and vestibular decreased more significantly in the postural control.


Subject(s)
Diabetes Mellitus, Type 2/physiopathology , Postural Balance , Case-Control Studies , Dizziness/complications , Humans , Proprioception , Vertigo/complications , Vestibule, Labyrinth/physiopathology , Vision, Ocular
9.
Life Sci ; 144: 148-55, 2016 Jan 01.
Article in English | MEDLINE | ID: mdl-26674463

ABSTRACT

AIMS: To investigate insulin secretion and content in islet ß cells after intravenous glucose load in mice. MATERIALS AND METHODS: Acute hyperglycemia (≥16.7 mmol/L) in C57BL/J6 mice was achieved by hyperglycemic clamp. Mice were divided into four groups: a 2-hour and a 4-hour high glucose-infusion (2 h-HG and 4 h-HG) with 25% dextrose groups and control groups with saline infusion of the same duration. Insulin levels and response were measured using intraperitoneal glucose tolerance test (IPGTT) in mice and glucose-stimulated insulin secretion (GSIS) for isolated islets after overnight culture. Immunohistochemistry and electron microscopy (EM) for islet ß cells were used after the hyperglycemic clamp to study morphologic changes of insulin granules and to assess the impact of acute glucose load on islet histology. KEY FINDINGS: Blood glucose at 15, 30, 60 and 120 min was significantly higher in 4 h-HG compared with the other groups. Serum plasma insulin significantly decreased only at 15 min as a first-phase insulin response (FPIR). Insulin secretion at 2.8 and 16.7 mmol/L glucose stimulus in 4 h-HG group decreased 77% and 64% more than those in 2 h-HG, respectively (P<0.05). Similarly, residual insulin content in islet ß cells after 2.8 and 16.7 mmol/L glucose challenge decreased 30% and 43% more than those in 2 h-HG, respectively (P<0.05). EM showed decreased insulin granules in islet cells and swollen mitochondria only in 4 h-HG. SIGNIFICANCE: Short time intravenous glucose load blunted FPIRs and decreased insulin content of islet ß cells.


Subject(s)
Glucose/pharmacology , Insulin-Secreting Cells/metabolism , Insulin/metabolism , Animals , Blood Glucose/metabolism , Cell Size/drug effects , Glucose Clamp Technique , Glucose Tolerance Test , Hyperglycemia/chemically induced , Hyperglycemia/metabolism , In Vitro Techniques , Insulin-Secreting Cells/drug effects , Insulin-Secreting Cells/pathology , Male , Mice , Mice, Inbred C57BL
10.
Nutr Metab (Lond) ; 12: 34, 2015.
Article in English | MEDLINE | ID: mdl-26445593

ABSTRACT

BACKGROUND: Severe calorie restriction (CR) is shown to improve or even reverse ß-cell dysfunction in patients with obesity and type 2 diabetes mellitus. However, whether mild to moderate CR can reverse ß-cell dysfunction induced by obesity and the underlying mechanism remain unclear. Autophagy plays an important role in maintaining mass, architecture and function of ß-cells. While the impact of CR on ß-cell autophagy is unknown. This study aims to investigate the effects of moderate CR on ß-cell function and autophagy activity in diet-induced obese (DIO) mice. METHODS: DIO C57BL/6 mice were subjected to 3 weeks of switching to normal chow (HF → NC group) or normal chow with 40 % CR (HF → NC CR group). Then hematoxylin-eosin and immunohistochemistry staining were performed to observe ß-cell morphology. ß-cell function was evaluated by intraperitoneal glucose tolerance test in vivo and static GSIS (glucose-stimulated insulin secretion) in isolated islets. ß-cell autophagy activity was determined by transmission electron microscope and western blot. RESULTS: In the HF → NC CR group, CR normalized body weights, completely restored glucose tolerance, early-phase and second-phase insulin secretion, insulin sensitivity, and islet size. CR also normalized insulin content and glucose-stimulated insulin secretion in isolated islets in vitro. Furthermore, ß-cell autophagy level was increased in the HF → NC CR group, but AMPK phosphorylation remained unchanged. Although HF → NC mice achieved moderate weight loss and normal glucose tolerance, their insulin secretion was not improved compared with obese control mice, and additionally, ß-cell autophagy was not activated in these mice. CONCLUSIONS: Moderate (40 %) CR to achieve normal weight reversed ß-cell dysfunction and insulin resistance, and restored glucose homeostasis in DIO mice. Furthermore, the up-regulation of ß-cell autophagy may play a role in this process, independent of AMPK activation.

11.
Zhonghua Yi Xue Za Zhi ; 95(12): 908-11, 2015 Mar 31.
Article in Chinese | MEDLINE | ID: mdl-26081052

ABSTRACT

OBJECTIVE: To explore the relationship between serum level of thyroxin-stimulating hormone (TSH) and development and progression of papillary thyroid microcarcinoma (PTMC) in nodular thyroid disease. METHODS: A total of 365 eligible patients with thyroid nodules undergoing initial thyroidectomy were enrolled, including 113 patients with PTMC diagnosed by postoperative pathology (PTMC group) and 252 patients with benign thyroid nodules (BTN group). Their clinical data were retrospectively reviewed. The serum levels of TSH in two groups and the proportion of PTMC in different serum TSH level groups in all patients were compared respectively. The relationship of preoperative serum TSH levels with tumor size and lymphatic metastasis in patients with PTMC were analyzed. RESULTS: No significant difference existed in serum TSH levels between PTMC and BTN groups (P > 0.05). The median age was younger in PTMC group than that in BTN group (Z = -2.877, P = 0.004). And the TGAb levels were higher in PTMC group than those in BTN group (Z = -2.887, P = 0.004). They were divided into 6 groups according to the serum TSH levels, and there weren't significant difference in the proportion of PTMC among those group (P > 0.05). Binary logistic regression analysis showed age was the only risk factor of PTMC (OR = 0.971, 95%CI: 0.953-0.990, P = 0.003). The serum TSH levels were positively correlated with tumor size in patients with PTMC (r = 0.218, P = 0.025). However, the proportions of lymphatic metastasis were comparable among different TSH levels groups in patients with PTMC (P > 0.05). CONCLUSION: Serum TSH is probably associated with the de novo oncogenesis of PTMC. However, serum TSH may be involved in the growth of preexisting PTMC.


Subject(s)
Carcinoma, Papillary , Thyroid Neoplasms , Humans , Lymphatic Metastasis , Retrospective Studies , Risk Factors , Thyroid Function Tests , Thyroid Nodule , Thyroidectomy , Thyroxine
12.
Zhonghua Nei Ke Za Zhi ; 53(12): 941-6, 2014 Dec.
Article in Chinese | MEDLINE | ID: mdl-25623559

ABSTRACT

OBJECTIVE: To assess the estimated 10-year risk of stroke among hypertensive outpatients known with diabetes from cardiovascular clinics of 36 tertiary hospitals in China and to analyze the characteristics of the risk factors and the 10-year risk of stroke between the southern and the northern patients. METHODS: A multi-center prevalence survey was conducted from October 2011 to June 2012. Hypertensive outpatients known with diabetes were enrolled from cardiovascular clinics of 36 tertiary hospitals in China. A total of 15 914 outpatients were included in the final analysis. The 10-year probability of stroke was evaluated by the Framingham stroke risk profile. According to the 10-year probability of stroke, patients were divided into low risk ( ≤ 5%), medium risk (6%∼9%) and high risk ( ≥ 10%). RESULTS: (1) Of all the hypertensive outpatients known with diabetes, the mean age was (64.6 ± 10.1) years and the mean systolic pressure was (138.7 ± 19.3) mmHg (1 mmHg = 0.133 kPa). Among them, 7.4% with atrial fibrillation, 11.2% with left ventricular hypertrophy, 57.2% with cardiovascular diseases, 17.1% smokers and 37.0% using mono-hypoglycemic agent. The southern patients who were older with more smokers had higher proportions of men and left ventricular hypertrophy, lower levels of systolic blood pressure, and lower proportions of other cardiovascular diseases than those of the northern patients ( all P < 0.05). (2) The mean 10-year probability of stroke was (20.9 ± 16.2) %. The southern patients had a higher mean 10-year probability of stroke than that of the northern patients [(22.4 ± 17.1) % vs (19.7 ± 15.2) %] (P < 0.01) . After adjusted by age and sex, the southern patients still had a higher mean 10-year probability of stroke (P < 0.05) . (3) All the patients had 7.7% with low risk, 17.4% with medium risk, and 74.9% with high risk. The southern patients had lower proportions of low and medium risk than those of the northern patients (6.7% vs 8.4%, 15.5% vs 18.9%), but had a higher proportion of high risk than that of the northern patients (77.7% vs 72.7%, all P < 0.01). CONCLUSIONS: Among the hypertensive outpatients known with diabetes from the cardiovascular clinics of our study, most of them were at the 10-year high risk of stroke. The southern patients had a higher mean 10-year probability of stroke than that of the northern patients.


Subject(s)
Ambulatory Care Facilities/statistics & numerical data , Blood Pressure , Hospitals/statistics & numerical data , Hypertension/ethnology , Outpatients , Stroke/ethnology , Aged , Antihypertensive Agents/therapeutic use , Asian People , Atrial Fibrillation , Cardiovascular Diseases/ethnology , China/epidemiology , Diabetes Mellitus/diagnosis , Diabetes Mellitus/drug therapy , Diabetes Mellitus/ethnology , Female , Humans , Hypertension/complications , Hypertension/drug therapy , Hypertrophy, Left Ventricular , Hypoglycemic Agents/administration & dosage , Male , Middle Aged , Obesity/epidemiology , Prevalence , Probability , Residence Characteristics , Risk Factors , Stroke/etiology , Tertiary Care Centers
13.
FEBS Lett ; 587(18): 2958-64, 2013 Sep 17.
Article in English | MEDLINE | ID: mdl-23954298

ABSTRACT

Enteropeptidase can cleave trypsinogen on the sequence of Asp-Asp-Asp-Asp-Lys and plays an important role in food digestion. The RANKL-RANK signalling pathway plays a pivotal role in bone remodelling. In this study, we reported that enteropeptidase can inhibit the RANKL-RANK signalling pathway through the cleavage of RANK. A surrogate peptide blocking assay indicated that enteropeptidase could specifically cleave RANK on the sequence NEEDK. Osteoclast differentiation assay and NF-κB activity assay confirmed that enteropeptidase could inhibit osteoclastogenesis in vitro through the cleavage of RANK. This is the first study to prove that the RANKL-RANK signalling pathway can be inhibited by cleavage of RANK instead of targeting RANKL.


Subject(s)
Bone and Bones/enzymology , Enteropeptidase/antagonists & inhibitors , Macrophages/enzymology , Osteoclasts/enzymology , Peptides/pharmacology , RANK Ligand/metabolism , Receptor Activator of Nuclear Factor-kappa B/metabolism , Amino Acid Motifs , Animals , Binding Sites , Bone and Bones/cytology , Bone and Bones/drug effects , Cell Differentiation , Cell Line , Enteropeptidase/genetics , Enteropeptidase/metabolism , Gene Expression Regulation , Macrophages/cytology , Macrophages/drug effects , Mice , Molecular Sequence Data , Osteoclasts/cytology , Osteoclasts/drug effects , Peptides/chemical synthesis , Protein Binding , Protein Interaction Domains and Motifs , Proteolysis , RANK Ligand/genetics , Receptor Activator of Nuclear Factor-kappa B/genetics , Sequence Homology, Amino Acid , Signal Transduction
14.
FEBS J ; 277(24): 5061-71, 2010 Dec.
Article in English | MEDLINE | ID: mdl-21073655

ABSTRACT

Defects in insulin secretion by pancreatic cells and/or decreased sensitivity of target tissues to insulin action are the key features of type 2 diabetes. It has been shown that excessive generation of reactive oxygen species (ROS) is linked to glucose-induced ß-cell dysfunction. However, cellular mechanisms involved in ROS generation in ß-cells and the link between ROS and glucose-induced ß-cell dysfunction are poorly understood. Here, we demonstrate a key role of NADPH oxidase 2 (NOX2)-derived ROS in the deterioration of ß-cell function induced by a high concentration of glucose. Sprague-Dawley rats were fed a high-fat diet for 24 weeks to induce diabetes. Diabetic rats showed increased glucose levels and elevated ROS generation in blood, but decreased insulin content in pancreatic ß-cells. In vitro, increased ROS levels in pancreatic NIT-1 cells exposed to high concentrations of glucose (33.3 mmol·L(-1)) were associated with elevated expression of NOX2. Importantly, decreased glucose-induced insulin expression and secretion in NIT-1 cells could be rescued via siRNA-mediated NOX2 reduction. Furthermore, high glucose concentrations led to apoptosis of ß-cells by activation of p38MAPK and p53, and dysfunction of ß-cells through phosphatase and tensih homolog (PTEN)-dependent Jun N-terminal kinase (JNK) activation and protein kinase B (AKT/PKB) inhibition, which induced the translocation of forkhead box O1 and pancreatic duodenal homeobox-1, followed by reduced insulin expression and secretion. In conclusion, NOX2-derived ROS could play a critical role in high glucose-induced ß-cell dysfunction through PTEN-dependent JNK activation and AKT inhibition.


Subject(s)
Glucose/pharmacology , Islets of Langerhans/drug effects , NADPH Oxidases/antagonists & inhibitors , Animals , Blood Glucose/analysis , Cell Line , Diabetes Mellitus, Experimental/enzymology , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Experimental/pathology , Insulin/metabolism , Islets of Langerhans/enzymology , Islets of Langerhans/pathology , Rats , Rats, Sprague-Dawley , Reactive Oxygen Species/metabolism
15.
J Biol Chem ; 285(44): 33718-26, 2010 Oct 29.
Article in English | MEDLINE | ID: mdl-20736162

ABSTRACT

It remains unclear how α-ketoisocaproate (KIC) and leucine are metabolized to stimulate insulin secretion. Mitochondrial BCATm (branched-chain aminotransferase) catalyzes reversible transamination of leucine and α-ketoglutarate to KIC and glutamate, the first step of leucine catabolism. We investigated the biochemical mechanisms of KIC and leucine-stimulated insulin secretion (KICSIS and LSIS, respectively) using BCATm(-/-) mice. In static incubation, BCATm disruption abolished insulin secretion by KIC, D,L-α-keto-ß-methylvalerate, and α-ketocaproate without altering stimulation by glucose, leucine, or α-ketoglutarate. Similarly, during pancreas perfusions in BCATm(-/-) mice, glucose and arginine stimulated insulin release, whereas KICSIS was largely abolished. During islet perifusions, KIC and 2 mM glutamine caused robust dose-dependent insulin secretion in BCATm(+/+) not BCATm(-/-) islets, whereas LSIS was unaffected. Consistently, in contrast to BCATm(+/+) islets, the increases of the ATP concentration and NADPH/NADP(+) ratio in response to KIC were largely blunted in BCATm(-/-) islets. Compared with nontreated islets, the combination of KIC/glutamine (10/2 mM) did not influence α-ketoglutarate concentrations but caused 120 and 33% increases in malate in BCATm(+/+) and BCATm(-/-) islets, respectively. Although leucine oxidation and KIC transamination were blocked in BCATm(-/-) islets, KIC oxidation was unaltered. These data indicate that KICSIS requires transamination of KIC and glutamate to leucine and α-ketoglutarate, respectively. LSIS does not require leucine catabolism and may be through leucine activation of glutamate dehydrogenase. Thus, KICSIS and LSIS occur by enhancing the metabolism of glutamine/glutamate to α-ketoglutarate, which, in turn, is metabolized to produce the intracellular signals such as ATP and NADPH for insulin secretion.


Subject(s)
Keto Acids/chemistry , Leucine/chemistry , Mitochondria/enzymology , Transaminases/genetics , Adenosine Triphosphate/chemistry , Animals , Female , Glucose/chemistry , Glucose/metabolism , Glutamine/chemistry , Insulin/metabolism , Insulin Secretion , Islets of Langerhans/cytology , Ketoglutaric Acids/chemistry , Mice , Mice, Transgenic , Oxygen/chemistry , Transaminases/metabolism
16.
J Appl Physiol (1985) ; 108(4): 941-9, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20133434

ABSTRACT

Exercise enhances branched-chain amino acid (BCAA) catabolism, and BCAA supplementation influences exercise metabolism. However, it remains controversial whether BCAA supplementation improves exercise endurance, and unknown whether the exercise endurance effect of BCAA supplementation requires catabolism of these amino acids. Therefore, we examined exercise capacity and intermediary metabolism in skeletal muscle of knockout (KO) mice of mitochondrial branched-chain aminotransferase (BCATm), which catalyzes the first step of BCAA catabolism. We found that BCATm KO mice were exercise intolerant with markedly decreased endurance to exhaustion. Their plasma lactate and lactate-to-pyruvate ratio in skeletal muscle during exercise and lactate release from hindlimb perfused with high concentrations of insulin and glucose were significantly higher in KO than wild-type (WT) mice. Plasma and muscle ammonia concentrations were also markedly higher in KO than WT mice during a brief bout of exercise. BCATm KO mice exhibited 43-79% declines in the muscle concentration of alanine, glutamine, aspartate, and glutamate at rest and during exercise. In response to exercise, the increments in muscle malate and alpha-ketoglutarate were greater in KO than WT mice. While muscle ATP concentration tended to be lower, muscle IMP concentration was sevenfold higher in KO compared with WT mice after a brief bout of exercise, suggesting elevated ammonia in KO is derived from the purine nucleotide cycle. These data suggest that disruption of BCAA transamination causes impaired malate/aspartate shuttle, thereby resulting in decreased alanine and glutamine formation, as well as increases in lactate-to-pyruvate ratio and ammonia in skeletal muscle. Thus BCAA metabolism may regulate exercise capacity in mice.


Subject(s)
Amino Acids, Branched-Chain/metabolism , Exercise Tolerance/physiology , Muscle, Skeletal/metabolism , Physical Conditioning, Animal/physiology , Transaminases/metabolism , Amino Acids, Branched-Chain/pharmacology , Ammonia/metabolism , Animals , Aspartic Acid/metabolism , Blood Glucose/analysis , Exercise Test , Exercise Tolerance/drug effects , Glucose/pharmacology , Insulin/pharmacology , Ketoglutaric Acids/metabolism , Lactic Acid/metabolism , Male , Maleates/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , Muscle, Skeletal/drug effects , Muscle, Skeletal/ultrastructure , Physical Exertion/drug effects , Physical Exertion/physiology , Transaminases/deficiency
17.
FEBS Lett ; 584(5): 995-1000, 2010 Mar 05.
Article in English | MEDLINE | ID: mdl-20102709

ABSTRACT

TNF-alpha-induced insulin resistance is associated with generation of reactive oxygen species (ROS). This study aims at defining the link between ROS production and hepatic insulin resistance. Treatment with TNF-alpha increased ROS generation through activating NADPH oxidase 3 (NOX3) in HepG2 hepatocytes. Down-regulation of NOX3 using siRNA prevented TNF-alpha-induced decrease of cellular glycogen. In the cells treated with TNF-alpha, there were NOX3-dependent activation of JNK, inhibition of IRS1 and phosphorylation of AKT/PKB and GSK. In conclusion, the effects of TNF-alpha on hepatic insulin resistance appear to be, at least in part, mediated by NOX3-derived ROS through a JNK pathway.


Subject(s)
Glycogen/metabolism , Hepatocytes/metabolism , JNK Mitogen-Activated Protein Kinases/metabolism , Membrane Proteins/metabolism , NADPH Oxidases/metabolism , Reactive Oxygen Species/metabolism , Blotting, Western , Cell Line, Tumor , Fluorescent Antibody Technique , Hepatocytes/drug effects , Humans , Immunohistochemistry , Insulin Resistance/genetics , Insulin Resistance/physiology , Membrane Proteins/genetics , NADPH Oxidases/genetics , RNA, Small Interfering , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/drug effects , Tumor Necrosis Factor-alpha/pharmacology
18.
Zhonghua Yi Xue Za Zhi ; 88(6): 374-7, 2008 Feb 05.
Article in Chinese | MEDLINE | ID: mdl-18581888

ABSTRACT

OBJECTIVE: To investigate the effects of intervention against glucotoxicity on improvement of the function and pathological changes of islet beta and alpha cells. METHODS: Thirty-six male Sprague Dawley rats were randomly divided into four equal groups: normal control (NC) group, fed with standard chow, high-fat (HF) group, fed with extra high-fat chow; diabetes mellitus (DM) control group, fed with high-fat chow for 8 weeks followed by 30 mg/kg streptozotocin injection to establish DM models; and insulin (INS) group, treated with subcutaneous injection of long-acting insulin (glargine, 0.5 U x kg(-1) x d(-1)) for 4 weeks after the establishment of DM models. 48 h, 2 weeks, and 4 weeks after the STZ injection to the 2 DM groups oral glucose tolerance test (OGTT) was performed to all rats. Peripheral blood samples were collected from the caudal vein. Serum insulin level was assayed by radioimmunoassay. Total serum cholesterol (TC) and triglyceride (TG) were measured by enzyme-colorimetric method. By the end of experiment the rats were killed with their pancreases taken out. Immunohistochemistry was used to observe the morphological changes of the islet beta and alpha cells. Beta cell and alpha cell masses were calculated by the proportions of positive area in the islet. Proinsulin mRNA level was detected by RT-PCR. Insulin protein content in islets was detected by Western blotting. RESULTS: Four weeks after the insulin intervention against glucotoxicity, the fasting blood glucose and blood glucose 2 h after sugar-taking of the INS group were both significantly lower than those of the DM group (both P < 0.01). The relative beta cell mass of the INS group was 0.38 +/- 0.08, significantly bigger, 2.45 times, that of the DM group (0.11 +/- 0.05, P < 0.01). The relative alpha cells mass in islets of the INS group was 0.16 +/- 0.04, significantly lower, by 43%, than that of the DM group (0.28 +/- 0.15, P < 0.01). The insulin contents in beta cells of the INS group was 0.58 +/- 0.03, significantly higher, by 70.6%, than that of the DM group (0.34 +/- 0.14, P < 0.01). The proinsulin mRNA level of the INS group was 1.52 +/- 0.14, significantly higher, by 20.6%, than that of the DM group. CONCLUSION: The morphology of islet beta, alpha cells in diabetic rats was improved by four weeks of Intervention against glucotoxicity improves the pathology of islet beta and alpha cells in diabetic and insulin synthesis.


Subject(s)
Diabetes Mellitus, Experimental/physiopathology , Glucose/toxicity , Islets of Langerhans/drug effects , Animals , Blood Glucose/metabolism , Blotting, Western , Cholesterol/blood , Colorimetry/methods , Diabetes Mellitus, Experimental/blood , Diabetes Mellitus, Experimental/chemically induced , Dietary Fats , Glucose Clamp Technique , Insulin/blood , Insulin/metabolism , Insulin Resistance , Islets of Langerhans/metabolism , Islets of Langerhans/pathology , Male , Proinsulin/genetics , Proinsulin/metabolism , Radioimmunoassay , Rats , Rats, Sprague-Dawley , Reverse Transcriptase Polymerase Chain Reaction , Triglycerides/blood
19.
Zhonghua Yi Xue Za Zhi ; 87(26): 1817-20, 2007 Jul 10.
Article in Chinese | MEDLINE | ID: mdl-17922989

ABSTRACT

OBJECTIVE: To investigate the differences on the diabetic foot problems and its risk factors in south and north of China. METHODS: Patients with foot problems were surveyed from January 1 to December 31, 2004 in 14 teaching hospitals located in different cities in China, including demographic data, present and past history of the foot problems and peripheral artery disease (PAD), the classification of the foot ulcers based on the Wagner' system, control of the hyperglycemia and lipids disorder, medical cost in hospital and the diabetic complications. All the patients were divided into two groups due to their geographical data, south and north. RESULTS: There were 285 and 349 patients for the group south and group north. No significant differences were found for duration of diabetes or foot problems, fasting or post-meal glucose, total cholesterol, triglycerides, HDL-C, and the numbers of patients with smoke, hypertension, nephropathy or neuropathy between the two groups. There were significant differences for the age (70 yrs vs 66 yrs), percentage of the patients with average person income with over RMB 1000 per month (57.7% vs 45.6%), coronary heart disease (42.6% vs 61.0%) and retinopathy (35.7% vs 49.5%), HbA1c (7.90% vs 8.80 %), LDL-C (2.75 mmol/L vs 2.98 mmol/L), WBC (6.70 x 10(9) vs 7.40 x 10(9)/L), HCT (0.37 vs 0.38), creatinine (87 micromol/L vs 76 micromol/L) and uric acid (333 mmol/L vs 271 mmol/L), and amputation rate (2.6% vs 9.7%) between south and north groups. Logistic analysis showed that severity of the foot problems was associated with ABI and WBC in south group, and with ABI, PLT and HCT in north group. CONCLUSION: Diabetic foot problems were more severe, with more risk factors and with more medical cost in north patients.


Subject(s)
Diabetes Mellitus, Type 2/epidemiology , Diabetic Foot/epidemiology , Age Factors , Aged , China/epidemiology , Diabetes Mellitus, Type 2/complications , Diabetic Foot/etiology , Humans , Middle Aged , Risk Factors
20.
Zhonghua Yi Xue Za Zhi ; 87(18): 1241-4, 2007 May 15.
Article in Chinese | MEDLINE | ID: mdl-17686256

ABSTRACT

OBJECTIVE: To investigate the characteristics of diabetic foot with neuropathy and its related factors. METHODS: 530 out- and in-patients in 14 grade A class 3 comprehensive hospitals in China with foot problems were surveyed. 337 of the 500 patients (63.58%) suffered from neuropathy, 172 (32.45%) with diabetic foot with simple neuropathy and 165 (31.13%) with simple neuropathy combined with peripheral artery disease (PAD). 193 of the 500 patients (36.42%) suffered from peripheral artery disease (PAD). 77.7% of ulcer were caused by physical factors. Questionnaire survey was conducted to collect the demographic data, present and past history, history of the hyperglycemia and lipid disorders, classification and phases of the foot ulcers based on Wagner' system and Texas system, characteristics of neuropathy and other diabetic complications, and relative risk factors. Detailed physical examination was performed, including 10 g nylon filament sensation examination. RESULTS: The duration of diabetic foot of the patients with simple neuropathy was 3 (1, 60) months, significantly shorter than that of the diabetic foot patients with PAD [5 (1, 96) months, P < 0.001]. The Wagner degree of ulcer was related to the duration of diabetes, economic income, foot deformity, nerve reflection, diapason vibration sensation of foot, sensation point of 10 g nylon filament, ankle/brachial index (ABI), foot artery pulse, fasting blood sugar (FBS) and glycated hemoglobin (HbA1c). Stepwise regression analysis revealed that ABI of left posterior tibial artery, vibration detection threshold and economic income were the most significant influencing factors of the degree of ulcer. CONCLUSION: Neuropathy ulcer is common in diabetic foot patients. The prognosis of healing in diabetic foot with neuropathy is prior to that of diabetic foot with PAD. The neuropathy and PAD of foot influence each other and aggravate the condition of diabetic foot. The examinations of diapason vibration sensation of foot, sensation point of 10 g nylon filament, and Achilles tendon reflex are simple and practical, and are worth recommending.


Subject(s)
Diabetic Foot/epidemiology , Diabetic Neuropathies/epidemiology , Aged , China/epidemiology , Diabetic Angiopathies/diagnosis , Diabetic Angiopathies/epidemiology , Diabetic Foot/diagnosis , Diabetic Neuropathies/diagnosis , Female , Humans , Male , Middle Aged , Regression Analysis , Surveys and Questionnaires
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