fibrin and 3-nitrotyrosine

We sought to investigate whether enhanced oxidation contributes to unfavorable fibrin clot properties in patients with diabetes.. We assessed plasma fibrin clot permeation (K s , a measure of the pore size in fibrin networks) and clot lysis time induced by recombinant tissue plasminogen activator (CLT) in 163 consecutive type 2 diabetic patients (92 men and 71 women) aged 65 ± 8.8 years with a mean glycated hemoglobin (HbA1c) of 6.8%. We also measured oxidative stress markers, including nitrotyrosine, the soluble form of receptor for advanced glycation end products (sRAGE), 8-iso-prostaglandin F2α (8-iso-PGF2α ), oxidized low-density lipoprotein (oxLDL), and advanced glycation end products (AGE).. There were inverse correlations between K s and nitrotyrosine, sRAGE, 8-iso-PGF2α , and oxLDL. CLT showed a positive correlation with oxLDL and nitrotyrosine but not with other oxidation markers. All these associations remained significant for K s after adjustment for fibrinogen, disease duration, and HbA1c (all P < 0.05), while oxLDL was the only independent predictor of CLT.. Our study shows that enhanced oxidative stress adversely affects plasma fibrin clot properties in type 2 diabetic patients, regardless of disease duration and glycemia control.

Topics: Aged; Aged, 80 and over; Blood Coagulation; Blood Glucose; Diabetes Mellitus, Type 2; Dinoprost; Female; Fibrin; Fibrinolysis; Glomerular Filtration Rate; Glycated Hemoglobin; Glycation End Products, Advanced; Humans; Kinetics; Lipoproteins, LDL; Male; Middle Aged; Oxidative Stress; Oxygen; Permeability; Receptor for Advanced Glycation End Products; Recombinant Proteins; Surveys and Questionnaires; Tissue Plasminogen Activator; Tyrosine

Apolipoprotein A-I (apoA-I), the major protein constituent within high-density lipoprotein (HDL), has been associated with antiatherogenic protection by mechanisms that include reverse cholesterol transport and antiinflammatory functions. To evaluate the proposed protective function of apoA-I, proteins modified by nitrating oxidants were evaluated in the aortic tissue and plasma of mice lacking the low-density lipoprotein receptor and apobec (LA) and LA mice with genetic deletion of apoA-I (LA-apoA-I(-/-)). The levels of nitrated proteins in aortic tissue quantified by liquid chromatography with online electrospray ionization tandem mass spectrometry (LC/ESI/MS/MS) were 6-fold higher in the LA-apoA-I(-/-) as compared with the LA mice. The quantitative analyses were corroborated by immunohistochemical and high-resolution immunoelectron microscopic evaluation of the lesions, which revealed abundant staining for nitrated proteins in the aortic root lesions of LA-apoA-I(-/-) as compared with the LA mice. Proteomic approaches based on affinity enrichment and site-specific adduct mapping identified unique specific protein targets for nitration in the plasma of LA-apoA-I(-/-) that were not present in the plasma of LA mice. In particular the nitration of fibrinogen was shown to accelerate fibrin clot formation. Another consequence of the augmented levels of nitrated proteins was the induction of humoral responses documented by the increased circulating immunoglobulins that recognize nitrotyrosine in LA-apoA-I(-/-) as compared with the LA mice. These data collectively support a protective function of apoA-I diminishing the burden of nitrative oxidants in these mice models of atherosclerosis.

Topics: Animals; Aorta; Apolipoprotein A-I; Atherosclerosis; Autoantibodies; Blood Coagulation; Blood Proteins; Cholesterol, HDL; Disease Models, Animal; Female; Fibrin; Fibrinogen; Immunohistochemistry; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Immunoelectron; Nitrogen; Oxidants; Proteomics; Tyrosine