The Role Of Peripheral Blood Monocytes And Thromboxane Synthase In Glucose Metabolism Dysfunction

OBJECTIVE To investigate the role of peripheral blood monocytes in the process of improving glucose metabolism dysfunction by gliclazide-modified release?gliclazide MR?,and the role of thromboxane synthase?Tbxas?in obesity,adipose tissue,and the relationship with glucose metabolism dysfunction.METHODS A total of 108 newly diagnosed diabetes patients by oral glucose tolerance test?OGTT?with no history of antihyperglycemia medication were treated with gliclazide MR for 16 weeks after baseline assessment,and underwent follow-up at weeks 2,4,8,12,and 16.The fasting plasma glucose?FPG?,fasting insulin?FINS?,HbA1c,GA,blood routine test,2-h plasma glucose and insulin levels et al were determined at baseline and week 16.Homeostasis model assessment of?-cell function?HOMA-??,insulin resistance index?HOMA-IR?,and body mass index?BMI?were calculated.Arginine stimulation tests were conducted under fasting conditions to evaluate potential?-cell function.The fasting and 2-h glucose were measured at week 2,4,8,12.The potassium inwardly-rectifying channel,subfamily J,member 11?KCNJ11?E23K was genotyped with restriction fragment length polymorphism?RFLP?in all patients.The effects of gliclazide MR treatment in different genotypes were compared.The peripheral blood cells,HOMA-IR,HOMA-?and acute insulin response at baseline and week 16 were compared,as well as the their relationship.Moreover,visceral?omental??n=25?and subcutaneous?n=25?adipose tissues were obtained from patients who underwent intra-abdominal surgery at University of Maryland Medical Center,including normal group,obesity group and diabetes group.TBXAS expression in adipose tissue between different group and its relationship with BMI were determined.The mouse 3T3-L1 fibroblasts,RAW264.7macrophage cell line,and primary macrophages obtained from the peritoneal lavage of C57BL/6J mice were cultured,and simulated with different inflammatory factors.Total RNA were isolated and subjected to quantitative real-time PCR analysis for the expression of Tbxas and Tbxa2r.Male wild-type?WT?,leptin-deficient obese?ob/ob?,Tbxas^+/-mice?all on a C57BL/6J genetic background?were consumed standard chow diet.Tbxas^-/-KO mice and Tbxas^+/+WT littermate controls were generated by crossing the Tbxas^+/-heterozygous breeding pairs.Four-week-old C57BL/6J male mice,or Tbxas WT and KO mice were placed on a high-fat diet or an isocaloric-matched low-fat diet.The indexes of test in Tbxas KO mice and Tbxas WT mice were as follows:metabolic markers,insulin sensitivity in peripheral tissue,whole-body inflammatory factors,different kinds markers in adipose tissue,histological analysis of adipose tissue et al.The data were analyzed with SPSS20.0 and GraphPad Prism software.RESULTS 1.At baseline,patients with KK displayed higher blood glucose and lower serum insulin levels after oral glucose compared with EE and EK?all P<0.05?.During the treatment,individuals with KK exhibited lower fasting glucose levels,and more likely to attain the standard fasting glucose level(P_log-rank=0.028)than the E allele carriers.At week 16,patients with a greater number of 23K showed larger augmentations in?acute insulin response,and patients with KK had higher variance in the changes in fasting insulin and?HOMA-?compared with EK.2.Only monocytes among differential peripheral leukocyte obviously decreased.Peripheral monocytes level on baseline was positively correlated with waist.The abdominal obesity patients showed larger augmentations in?monocytes and?acute insulin secretion.There were significant positive correlation between?monocytes and?acute insulin secretion.The correlation disappeared after adjusting for age,waist and doseage at baseline.3.Thromboxane synthase can be produced by activated monocyte-macrophage system.The expression levels of Tbxas and Tbxa2r in visceral?epididymal?white adipose tissue were markedly upregulated in both genetic?leptin-deficient ob/ob?and diet-induced obese?DIO?mouse models.The expression level of TBXAS in visceral adipose tissue was significantly higher in obese and diabetic humans.Most of the Tbxas and Tbxa2r transcripts found in the adipose tissue were produced by stromal vascular fraction?SVF?rather than adipocytes.The expression of Tbxas and Tbxa2r were significantly upregulated in macrophages stimulated with inflammatory factors,but not in 3T3-L1 adipocytes.Mice lacking Tbxas had similar weight gain,food intake,and energy expenditure.Loss of Tbxas,however,markedly enhanced insulin sensitivity in mice fed a low-fat diet.Improvement in glucose homeostasis was correlated with the upregulated expression of multiple secreted metabolic regulators?Ctrp3,Ctrp9,and Ctrp12?in the subcutaneous fat depot.Following a challenge with a high-fat diet,Tbxas deficiency led to attenuated adipose tissue fibrosis and reduced circulating IL-6 levels without affecting adipose tissue macrophages;these changes,however,were not sufficient to improve whole-body insulin action.CONCLUSIONS In Chinese newly diagnosed patients with type 2 diabetes,KCNJ11 E23K polymorphism has impact on the effect of gliclazide by affecting islet?cell function.Waist impacts the change of peripheral blood monocytes after gliclazide treatment,and peripheral blood monocytes involve in influencing effect of gliclazide.Tbxas expressed by activated monocyte-macrophage system is related to obesity and hyperglycemia.Inhibiting Tbxas can modulate peripheral tissue insulin sensitivity and adipose tissue fibrosis,and improve glucose metabolic homeostasis.