thromboplastin and Diabetic-Retinopathy

Early growth response-1 (Egr-1) protein upregulation is reported in diabetes and vascular disorders. This study aims at deciphering its role in hyperglycemia induced changes of retinal endothelium. Human retinal endothelial cells (hRECs) were exposed to hyperglycemia (25mM) and normoglycemia (5.5mM). Gene silencing was done using siRNA against Egr-1. Transcript and protein level analysis of Egr-1 and gene targets were done using qPCR and immunoblotting respectively in hRECs, diabetic and nondiabetic human retina and immunofluorescence for localization in retinal sections. Hyperglycemia induced Egr-1 and vascular endothelial growth factor-A (VEGF-A) but not pigment epithelium derived factor (PEDF) in hRECs. Expression of Egr-1 repressor NGFI-A binding protein-2 (NAB-2) was unaltered. Egr-1 downstream gene targets, tissue factor (TF) and intercellular adhesion molecule-1 (ICAM-1) expression were increased in hRECs which was reduced by Egr-1 silencing in hyperglycemia. Diabetic retina, showed an increase in Egr-1, VEGF-A and gene target TF, ICAM-1 but not NAB-2 and PEDF similar to the changes seen in hyperglycemic hRECs. Hyperglycemic induction of Egr-1 and absence of NAB-2 repression in retinal endothelium, up-regulates downstream genes involved in pro-thrombotic and pro-inflammatory pathways linking Egr-1 in diabetes mediated vascular aberration of retina.

Topics: Cells, Cultured; Diabetic Retinopathy; Early Growth Response Protein 1; Endothelial Cells; Eye Proteins; Glucose; Humans; Hyperglycemia; Intercellular Adhesion Molecule-1; Nerve Growth Factors; Repressor Proteins; Retinal Vessels; Serpins; Signal Transduction; Thromboplastin; Up-Regulation; Vascular Endothelial Growth Factor A

Type 2 diabetes mellitus (T2DM) is associated with increased coagulability and vascular complications. Circulating microparticles (MPs) are involved in thrombosis, inflammation, and angiogenesis. However, the role of MPs in T2DM vascular complications is unclear. We characterised the cell origin and pro-coagulant profiles of MPs obtained from 41 healthy controls and 123 T2DM patients with coronary artery disease, retinopathy and foot ulcers. The effects of MPs on endothelial cell coagulability and tube formation were evaluated. Patients with severe diabetic foot ulcers expressed the highest levels of MPs originated from platelet and endothelial cells and negatively-charged phospholipid-bearing MPs. MP coagulability, calculated from MP tissue factor (TF) and TF pathway inhibitor (TFPI) ratio, was low in healthy controls and in diabetic retinopathy patients (<0.7) but high in patients with coronary artery disease and foot ulcers (>1.8, p≥0.002). MPs of all T2DM patients induced a more than two-fold increase in endothelial cell TF (antigen and gene expression) but did not affect TFPI levels. Tube networks were longest and most stable in endothelial cells that were incubated with MPs of healthy controls, whereas no tube formation occurred in MPs of diabetic patients with coronary artery disease. MPs of diabetic retinopathy and diabetic foot ulcer patients induced branched tube networks that were unstable and collapsed over time. This study demonstrates that MP characteristics are related to the specific type of vascular complications and may serve as a bio-marker for the pro- coagulant state and vascular pathology in patients with T2DM.

Topics: Aged; Blood Coagulation; Case-Control Studies; Cell-Derived Microparticles; Coronary Artery Disease; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Foot; Diabetic Retinopathy; Endothelial Cells; Female; Gene Expression; Humans; Lipoproteins; Male; Middle Aged; Neovascularization, Pathologic; Platelet Activation; Thromboplastin

An increased mRNA expression of genes related to blood coagulation has been demonstrated in an experimental retinal detachment model but has not yet been confirmed in human clinical specimens. Tissue factor (TF), the initiating factor of blood coagulation, may be a determinant of the extent of tissue injury after rhegmatogenous retinal detachment (RRD). This study was conducted to determine whether subretinal fluid and vitreous fluid collected from patients with RRD have a procoagulant effect.. Calibrated thrombin generation (CAT) was used to investigate the thrombogenic properties of 28 subretinal fluids collected during scleral buckling surgery for RRD. Further, the thrombogenic properties of vitreous fluids from RRD (n = 12), macular pucker (n = 5), macular hole (n = 6), and proliferative diabetic retinopathy (n = 5) were compared with the properties of eye bank eyes (n = 11), which served as control specimens. The procoagulant activity of TF was determined with Western blot analysis.. The addition of subretinal fluid from all RRD patients (28/28, 100%) induced thrombin generation in normal and severely factor (F)XII-deficient plasma. Contrary to the subretinal fluid, the addition of vitreous fluids from various ocular disorders evoked very little thrombin generation in normal and severely FXII-deficient plasma (4/12, 33% RRD; 1/5, 20% macular pucker; 0/6, 0% macular hole; 0/5, 0% proliferative diabetic retinopathy; and 2/11, 18% eye bank eyes). The procoagulant activity in subretinal fluid was almost completely neutralized by antibodies against human TF. The presence of TF in subretinal fluid was confirmed by Western blot.. Subretinal fluid of patients with RRD induces high procoagulant activity, determined by measuring the level of tissue factor.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Blotting, Western; Body Fluids; Diabetic Retinopathy; Exudates and Transudates; Female; Humans; Macular Degeneration; Male; Middle Aged; Retinal Detachment; Retinal Perforations; Scleral Buckling; Thrombin; Thromboplastin; Vitreous Body; Young Adult

Patients with diabetes mellitus (DM) are associated with an increased risk of thrombosis, and are susceptible to a series of complications including nephropathy. It has also been known that plasma tissue factor (TF) antigen levels increase significantly in certain disease states. To investigate the clinical significance of an association with the various complications in patients with type 2 non-insulin-dependent DM (NIDDM), we measured the plasma levels of TF antigen in 63 patients (35 males and 28 females, mean age 60.8 yrs) with NIDDM and in 22 normal subjects (14 males and 8 females, mean age 56.0 yrs). The mean concentrations of TF were higher for patients with NIDDM (253.7 +/- 144.9 pg/ml) than in normal subjects (187.3 +/- 108.7 pg/ml with marginal statistical significance (p= 0.0530). The TF levels were higher for patients with a nephropathy than for patients without a nephropathy (p=0.0402). There was a significant positive correlation between levels of TF and BUN (r=0.84, p < 0.0001) or creatinine (r=0.93, p < 0.0001). However, TF levels were found to be similar for both groups with and without thrombosis, neuropathy, retinopathy, or infection. These results suggest that plasma TF antigen levels may be associated with nephropathy and they may reflect a renal dysfunction in NIDDM.

Topics: Biomarkers; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Diabetic Retinopathy; Female; Humans; Infections; Male; Middle Aged; Thromboplastin; Thrombosis

Tissue factor (TF) is a cellular initiator of the coagulation cascade and is upregulated by the major factors of diabetic angiopathy, TF might thus be one of the key molecules in diabetic retinopathy (DR).. To measure TF in diabetic eyes and evaluate its possible role in DR.. TF concentration in the aqueous humor of the eyes in 44 patients with diabetes and 35 age-matched control patients was evaluated by ELISA. The concentration of TF in aqueous humor (AH) was compared with the grade of DR. The concentration of TF in AH was also compared with duration of diabetes, renal function, and blood glucose control. The serum TF concentration in each group was also compared. The correlation between the serum TF and aqueous TF in each patient was analyzed. The effect of vascular endothelial growth factor (VEGF) on the TF activity of cultured bovine retinal endothelial cells was evaluated.. The mean TF concentration in AH was higher in patients with active proliferative DR (244.5 pg/ml) than in either those with non-proliferative DR (132.4 pg/ml, P<0.05) or the control patients (114.9 pg/ml, P<0.01). The serum TF concentration in active proliferative DR patients (348.3 pg/ml) was significantly higher than in either non-proliferative DR patients, (235.9 pg/ml, P<0.01) or in the controls (223.5 pg/ml, P<0.01). However, the TF concentration of AH was not significantly correlated to that of the serum in each patient. The TF concentration in AH closely correlated with the grade of DR and protein concentration. VEGF increased the biological activity of TF in vitro.. The origin of TF in AH, however, is still not clearly understood. Nonetheless, TF in AH directly reflects the severity of ocular diabetic change, and the present results indicate that TF indeed plays some role in the progression of DR.

Topics: Adult; Aged; Aged, 80 and over; Aqueous Humor; Cells, Cultured; Diabetic Retinopathy; Disease Progression; Endothelial Growth Factors; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Female; Humans; Lymphokines; Male; Middle Aged; Retinal Vessels; Thromboplastin; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

There is overwhelming evidence that platelets from diabetic individuals are hyperreactive, not only when microvascular complications are apparent, but already at an early stage of the disease. There is still controversy about the question of whether primary hyperreactive platelets may contribute to the origin or progression of microangiopathy or whether diabetic platelet hyperfunctionality is just a logical consequence of a continuous low-grade activation of platelets by contact with a diseased microvascular wall. As a consequence of platelet activation, the outer layer of its phospholipid membrane is more procoagulant than in the quiescent state, stimulating thrombin formation in plasma. This platelet function is called platelet procoagulant activity. We studied platelet prothrombinase activity (PPA), a final pathway platelet procoagulant activity of type 1 diabetic platelets, and looked for an eventual correlation with microvascular disease (background retinopathy) and mean platelet volume (MPV). Stypven clotting times (SCTs), reflecting PPA expression, and MPV of citrated platelet-rich plasma (PRP), were measured in 21 patients with type 1 diabetes-10 with and 11 without background retinopathy-under clinically acceptable metabolic control and compared them to 20 disease-free voluntary controls. We also compared PPA expression and MPV in diabetic individuals with and without retinopathy. With the SCT, a selective test adapted for studying PPA in PRP, we found hyperexpression of PPA in all diabetic patients. We found no difference in MPV between diabetic and control PRP. Comparing patients with and without background retinopathy we found no significant difference in PPA expression. From these results, we suggest that the phospholipid surface of diabetic platelets, more than the surface of normal control platelets, stimulate the expression of PPA. This diabetic platelet coagulant anomaly was not related to an increased platelet mass (higher MPV) nor to the presence of microangiopathy. We conclude that PPA hyperexpression is associated with patients with type 1 diabetes, already occurring in an early stage of the disease, and not necessarily a consequence of early-stage microvascular disease, because the anomaly is also demonstrable, in the same degree, in patients with diabetes without microangiopathy.

Topics: Adult; Aged; Blood Coagulation; Blood Platelets; Diabetes Mellitus, Type 1; Diabetic Retinopathy; Female; Glycated Hemoglobin; Humans; Male; Middle Aged; Platelet Count; Reference Values; Thromboplastin

Patients with late diabetic complications have increased levels of parameters indicating activation of coagulation (Takakashi et al., 1989; Ceriello, 1993; Murakami et al., 1993; Kario et al., 1995; Shimizu et al., 1995; Yokoyama et al., 1996), endothelial cell damage (Jensen, 1989; Iwashima et al., 1990; Sernau et al., 1995; Gabath et al., 1996). TF is believed to activate the coagulation mechanism in patients with late complications of diabetes. We studied the TF antigen plasma levels in 72 patients with diabetes mellitus (36 type I, 36 type II) with respect to its relevance as a marker of microvascular diabetic complications. TF levels did not correlate with macrovascular disease, diabetes type or age. Sixty patients with decreased renal function not due to diabetes were studied for evaluation of the contribution of renal failure to TF antigen plasma levels. We did not find a significant correlation of TF with s-creatinine in non diabetic patients (r = 0.27, p > 0.05). However, TF levels were elevated in diabetic patients with microvascular disease. Patients with retinopathy had higher TF levels than without (0.30 ng/ml vs 0.11 ng/ml, p < 0.007). When patients were divided into subgroups according to the urine albumin concentration, TF antigen of patients without albuminuria (0.019 ng/ml, n = 25) did not differ from patients with microalbuminuria (0.095 ng/ml, n = 19 p > 0.05). However, TF levels were significantly higher in patients with macroalbuminuria (n = 28; 0.215 ng/ml, p < 0.005). Thus activation of coagulation in patients with microvascular complications of diabetes may be triggered by tissue factor.

Topics: Adult; Aged; Albuminuria; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Retinopathy; Enzyme-Linked Immunosorbent Assay; Female; Humans; Kidney Diseases; Male; Middle Aged; Thromboplastin

In 28 diabetics, classified into two groups according to the presence or absence of diabetic retinopathy, the following indices were examined: glycohemoglobin, factor VIII/von Willebrand, alpha-I-antitrypsin and alpha-2-macroglobulin. Factor VIII/von Willebrand and alpha-2-macroglobulin showed no changes in diabetes mellitus. Alpha-I-antitrypsin was statistically significantly decreased (p less than 0.05). Glycohemoglobin was significantly increased. No statistically significant differences were found between the two groups of diabetic patients (with and without retinopathy) studied for all indices examined.

Topics: Adult; Aged; alpha 1-Antitrypsin; alpha-Macroglobulins; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Retinopathy; Female; Glycated Hemoglobin; Humans; Male; Middle Aged; Thromboplastin; von Willebrand Factor

Topics: Antigens; Diabetic Retinopathy; Female; Humans; Male; Thrombelastography; Thromboplastin