thromboplastin and Insulin-Resistance

Clinical and epidemiological studies support a connection between obesity and thrombosis, involving elevated expression of the prothrombotic molecules plasminogen activator inhibitor-1 and tissue factor (TF) and increased platelet activation. Cardiovascular diseases and metabolic syndrome-associated disorders, including obesity, insulin resistance, type 2 diabetes, and hepatic steatosis, involve inflammation elicited by infiltration and activation of immune cells, particularly macrophages, into adipose tissue. Although TF has been clearly linked to a procoagulant state in obesity, emerging genetic and pharmacologic evidence indicate that TF signaling via G protein-coupled protease-activated receptors (PAR2, PAR1) additionally drives multiple aspects of the metabolic syndrome. TF-PAR2 signaling in adipocytes contributes to diet-induced obesity by decreasing metabolism and energy expenditure, whereas TF-PAR2 signaling in hematopoietic and myeloid cells drives adipose tissue inflammation, hepatic steatosis, and insulin resistance. TF-initiated coagulation leading to thrombin-PAR1 signaling also contributes to diet-induced hepatic steatosis and inflammation in certain models. Thus, in obese patients, clinical markers of a prothrombotic state may indicate a risk for the development of complications of the metabolic syndrome. Furthermore, TF-induced signaling could provide new therapeutic targets for drug development at the intersection between obesity, inflammation, and thrombosis.

Topics: Adipocytes; Adipose Tissue; Animals; Cardiovascular Diseases; Gene Expression Regulation; Humans; Inflammation; Insulin Resistance; Macrophages; Metabolic Syndrome; Mice; Mice, Obese; Models, Biological; Obesity; Plasminogen Activator Inhibitor 1; Receptor, PAR-1; Receptor, PAR-2; Risk Factors; Signal Transduction; T-Lymphocytes, Regulatory; Thrombophilia; Thromboplastin; Thrombosis

To determine the utility of estimated glucose disposal rate (eGDR) as a candidate biomarker for thrombotic biomarkers in patients with type 1 diabetes (T1D).. We reanalysed baseline pretreatment data in a subset of patients with T1D from two previous RCTs, consisting of a panel of thrombotic markers, including fibrinogen, tissue factor (TF) activity, and plasminogen-activator inhibitor (PAI)-1, and TNFα, and clinical factors (age, T1D duration, HbA1c, insulin requirements, BMI, blood pressure, and eGDR). We employed univariate linear regression models to investigate associations between clinical parameters and eGDR with thrombotic biomarkers.. Thirty-two patients were included [mean ± SD age 31 ± 7 years, HbA1c of 58 ± 9 mmol/mol (7.5 ± 0.8%), eGDR 7.73 ± 2.61]. eGDR negatively associated with fibrinogen (P < 0.001), PAI-1 concentrations (P = 0.005), and TF activity (P = 0.020), but not TNFα levels (P = 0.881). We identified 2 clusters of patients displaying significantly different characteristics; 56% (n = 18) were categorised as 'higher-risk', eliciting significantly higher fibrinogen (+ 1514 ± 594 μg/mL; P < 0.001), TF activity (+ 59.23 ± 9.42 pmol/mL; P < 0.001), and PAI-1 (+ 8.48 ± 1.58 pmol/dL; P < 0.001), HbA1c concentrations (+ 14.20 ± 1.04 mmol/mol; P < 0.001), age (+ 7 ± 3 years; P < 0.001), duration of diabetes (15 ± 2 years; P < 0.001), BMI (+ 7.66 ± 2.61 kg/m. Compared to BMI and insulin requirements, classical surrogates of insulin resistance, eGDR is a suitable and superior thrombotic risk indicator in T1D.. ISRCTN4081115; registered 27 June 2017.

Topics: Adult; Biomarkers; Blood Coagulation; Blood Glucose; Body Mass Index; Cluster Analysis; Diabetes Mellitus, Type 1; Female; Fibrinogen; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Male; Plasminogen Activator Inhibitor 1; Platelet Aggregation; Risk Assessment; Thromboplastin; Thrombosis

Adipocyte development and differentiation have an important role in the aetiology of obesity and its co-morbidities

Topics: Adipocytes; Adipogenesis; Animals; Diabetes Mellitus, Type 2; Female; Gene Expression Profiling; Humans; Insulin Resistance; Male; Mice; Paracrine Communication; Single-Cell Analysis; Stem Cells; Stromal Cells; Subcutaneous Fat; Thromboplastin

Failure to inhibit hepatic gluconeogenesis is a major mechanism contributing to fasting hyperglycemia in type 2 diabetes and, along with steatosis, is the hallmark of hepatic insulin resistance. Obesity is associated with chronic inflammation in multiple tissues, and hepatic inflammation is mechanistically linked to both steatosis and hepatic insulin resistance. Here, we delineate a role for coagulation signaling via tissue factor (TF) and proteinase-activated receptor 2 (PAR2) in obesity-mediated hepatic inflammation, steatosis, and gluconeogenesis. In diet-induced obese mice, TF tail signaling independent of PAR2 drives CD11b(+)CD11c(+) hepatic macrophage recruitment, and TF-PAR2 signaling contributes to the accumulation of hepatic CD8(+) T cells. Transcripts of key pathways of gluconeogenesis, lipogenesis, and inflammatory cytokines were reduced in high-fat diet-fed mice that lack the cytoplasmic domain of TF (F3) (TF(ΔCT)) or that are deficient in PAR2 (F2rl1), as well as by pharmacological inhibition of TF-PAR2 signaling in diet-induced obese mice. These gluconeogenic, lipogenic, and inflammatory pathway transcripts were similarly reduced in response to genetic ablation or pharmacological inhibition of TF-PAR2 signaling in hematopoietic cells and were mechanistically associated with activation of AMP-activated protein kinase (AMPK). These findings indicate that hematopoietic TF-PAR2 signaling plays a pivotal role in the hepatic inflammatory responses, steatosis, and hepatic insulin resistance that lead to systemic insulin resistance and type 2 diabetes in obesity.

Topics: AMP-Activated Protein Kinases; Animals; Diabetes Mellitus, Type 2; Fatty Liver; Gluconeogenesis; Hematopoietic Stem Cells; Hepatitis; Insulin Resistance; Mice; Mice, Knockout; Mice, Obese; Obesity; Receptor, PAR-2; Signal Transduction; Thromboplastin

Topics: Diabetes Mellitus, Type 2; Humans; Insulin Resistance; Monocytes; Thromboplastin

Tissue factor, the initiator of the coagulation cascade, mediates coagulation factor VIIa-dependent activation of protease-activated receptor 2 (PAR2). Here we delineate a role for this signaling pathway in obesity and its complications. Mice lacking PAR2 (F2rl1) or the cytoplasmic domain of tissue factor were protected from weight gain and insulin resistance induced by a high-fat diet. In hematopoietic cells, genetic ablation of tissue factor-PAR2 signaling reduced adipose tissue macrophage inflammation, and specific pharmacological inhibition of macrophage tissue factor signaling rapidly ameliorated insulin resistance. In contrast, nonhematopoietic cell tissue factor-VIIa-PAR2 signaling specifically promoted obesity. Mechanistically, adipocyte tissue factor cytoplasmic domain-dependent VIIa signaling suppressed Akt phosphorylation with concordant adverse transcriptional changes of key regulators of obesity and metabolism. Pharmacological blockade of adipocyte tissue factor in vivo reversed these effects of tissue factor-VIIa signaling and rapidly increased energy expenditure. Thus, inhibition of tissue factor signaling is a potential therapeutic avenue for improving impaired metabolism and insulin resistance in obesity.

Topics: Adipose Tissue; Animals; Bone Marrow Transplantation; Diet, High-Fat; Factor VIIa; Glucose; Inflammation; Insulin Resistance; Lipid Metabolism; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Obesity; Receptor, PAR-2; Signal Transduction; Thromboplastin; Transplantation Chimera

The metabolic syndrome (MetS) is a cluster of cardiovascular risk factors closely linked to inflammation and insulin resistance (IR). Tissue factor (TF) is an initiator of the extrinsic coagulation cascade and is expressed on peripheral blood monocytes and macrophages in atherosclerotic plaques. Monocytes are the principle cells capable of TF synthesis. Therefore, TF plays an important role in both thrombosis and atherosclerosis. Elevated levels of lipopolysaccharide (LPS), a strong stimulator of TF, have been observed in patients with MetS. No study has investigated the relationship between monocyte TF activity and inflammation, and IR in MetS.. Peripheral blood mononuclear cells (PBMCs) were collected from 40 normal subjects and 77 patients with MetS. Mononuclear cell TF procoagulant activity (MPCA) was measured with and without 100 pg/ml LPS stimulation using a 1-stage clotting assay and expressed as the mean +/- SD (mU TF/10(6) PBMCs). MPCA in MetS was significantly greater than in normal subjects (without LPS: 88.0+/-74.8 vs 52.6+/-9.8 mU TF/10(6) PBMCs, P<0.001; with LPS: 269.6+/-165.6 vs 158.6+/-42.8 mU TF/10(6) PBMCs, P<0.001). The LPS-stimulated log MPCA in MetS patients was significantly associated with homeostasis model assessment of IR (r=0.256, P=0.024) and log high-sensitivity C-reactive protein (r=0.332, P=0.003).. Upregulation of monocyte TF is significantly associated with low-grade inflammation and IR in MetS.

Topics: Aged; C-Reactive Protein; Chronic Disease; Disease Progression; Female; Homeostasis; Humans; In Vitro Techniques; Inflammation; Insulin Resistance; Lipopolysaccharides; Male; Metabolic Syndrome; Middle Aged; Monocytes; Risk Factors; Thromboplastin; Up-Regulation

Altered expression of proteins of the fibrinolytic and coagulation cascades in obesity may contribute to the cardiovascular risk associated with this condition. In spite of this, the zymogenic nature of some of the molecules and the presence of variable amounts of activators, inhibitors, and cofactors that alter their activity have made it difficult to accurately monitor changes in the activities of these proteins in tissues where they are synthesized. Thus, as a first approach to determine whether tissue factor (TF) expression is altered in obesity, this study examined changes in TF mRNA in various tissues from lean and obese (ob/ob and db/db) mice. TF gene expression was elevated in the brain, lung, kidney, heart, liver, and adipose tissues of both ob/ob and db/db mice compared with their lean counterparts. In situ hybridization analysis indicated that TF mRNA was elevated in bronchial epithelial cells in the lung, in myocytes in the heart, and in adventitial cells lining the arteries including the aortic wall. Obesity is associated with insulin resistance and hyperinsulinemia, and administration of insulin to lean mice induced TF mRNA in the kidney, brain, lung, and adipose tissue. These observations suggest that the hyperinsulinemia associated with insulin-resistant states, such as obesity and noninsulin-dependent diabetes mellitus, may induce local TF gene expression in multiple tissues. The elevated TF may contribute to the increased risk of atherothrombotic disease that accompanies these conditions.

Topics: Adipose Tissue; Animals; Brain Chemistry; Gene Expression Regulation; Hyperinsulinism; In Situ Hybridization; Insulin; Insulin Resistance; Kidney; Liver; Lung; Male; Mice; Mice, Inbred C57BL; Mice, Obese; Myocardium; Obesity; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Thromboplastin