Oxidative modification of fibrinogen is associated with altered function and structure in the subacute phase of myocardial infarction.
OBJECTIVE
Among plasma proteins, fibrinogen represents a major target of oxidative modifications. In patients with post-acute myocardial infarction (6 months after the acute event), fibrinogen oxidation-induced carbonyls and fibrinogen function were estimated using in vitro and ex vivo approaches. Fibrinogen structural features and clot architecture were also explored.


RESULTS
In 39 patients with post-acute myocardial infarction and 28 age-, sex-, and risk factor-matched controls, oxidative stress markers (in plasma and in purified fibrinogen fractions), thrombin-catalyzed fibrin polymerization, and plasmin-induced fibrin lysis were estimated. Circular dichroism spectra of purified fibrinogen extracts, electron microscopy, and differential interference contrast microscopy analyses of fibrin clots were also performed. Marked signs of oxidative stress in plasma (P<0.01 versus controls) and, correspondingly, an increased extent of fibrinogen carbonylation (3.5-fold over control values; P<0.01 versus controls) were observed in patients. Furthermore, fibrinogen fractions purified from patients exhibited significantly reduced clotting ability and decreased susceptibility to plasmin-induced lysis (P<0.01 versus controls). Alterations in fibrinogen secondary structure, as suggested by circular dichroism spectroscopy, and in fibrin clot architecture, as analyzed by electron and differential interference contrast microscopy, were also identified.


CONCLUSIONS
Here, we report for the first time that patients with post-acute myocardial infarction present with an overall imbalance in redox status and marked fibrinogen carbonylation associated with altered fibrinogen function, thus suggesting a role for carbonylation as a direct mechanism of fibrinogen function. The observed features occur along with modifications in protein structure and in clot architecture.
From the Department of Experimental and Clinical Biomedical Sciences (M.B., G.B., N.T., C.F.), Department of Clinical and Experimental Medicine, Thrombosis Centre (R.M., A.M.G., B.G., G.F.G., R.A.), and Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, Research Unit of Histology and Embryology (D.B.), University of Florence, Florence, Italy; and Don Carlo Gnocchi Foundation, Florence, Italy (A.M.G., G.F.G.).
Matteo
M
Becatti
From the Department of Experimental and Clinical Biomedical Sciences (M.B., G.B., N.T., C.F.), Department of Clinical and Experimental Medicine, Thrombosis Centre (R.M., A.M.G., B.G., G.F.G., R.A.), and Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, Research Unit of Histology and Embryology (D.B.), University of Florence, Florence, Italy; and Don Carlo Gnocchi Foundation, Florence, Italy (A.M.G., G.F.G.).
Rossella
R
Marcucci
From the Department of Experimental and Clinical Biomedical Sciences (M.B., G.B., N.T., C.F.), Department of Clinical and Experimental Medicine, Thrombosis Centre (R.M., A.M.G., B.G., G.F.G., R.A.), and Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, Research Unit of Histology and Embryology (D.B.), University of Florence, Florence, Italy; and Don Carlo Gnocchi Foundation, Florence, Italy (A.M.G., G.F.G.).
Giulia
G
Bruschi
From the Department of Experimental and Clinical Biomedical Sciences (M.B., G.B., N.T., C.F.), Department of Clinical and Experimental Medicine, Thrombosis Centre (R.M., A.M.G., B.G., G.F.G., R.A.), and Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, Research Unit of Histology and Embryology (D.B.), University of Florence, Florence, Italy; and Don Carlo Gnocchi Foundation, Florence, Italy (A.M.G., G.F.G.).
Niccolò
N
Taddei
From the Department of Experimental and Clinical Biomedical Sciences (M.B., G.B., N.T., C.F.), Department of Clinical and Experimental Medicine, Thrombosis Centre (R.M., A.M.G., B.G., G.F.G., R.A.), and Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, Research Unit of Histology and Embryology (D.B.), University of Florence, Florence, Italy; and Don Carlo Gnocchi Foundation, Florence, Italy (A.M.G., G.F.G.).
Daniele
D
Bani
From the Department of Experimental and Clinical Biomedical Sciences (M.B., G.B., N.T., C.F.), Department of Clinical and Experimental Medicine, Thrombosis Centre (R.M., A.M.G., B.G., G.F.G., R.A.), and Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, Research Unit of Histology and Embryology (D.B.), University of Florence, Florence, Italy; and Don Carlo Gnocchi Foundation, Florence, Italy (A.M.G., G.F.G.).
Anna Maria
AM
Gori
From the Department of Experimental and Clinical Biomedical Sciences (M.B., G.B., N.T., C.F.), Department of Clinical and Experimental Medicine, Thrombosis Centre (R.M., A.M.G., B.G., G.F.G., R.A.), and Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, Research Unit of Histology and Embryology (D.B.), University of Florence, Florence, Italy; and Don Carlo Gnocchi Foundation, Florence, Italy (A.M.G., G.F.G.).
Betti
B
Giusti
From the Department of Experimental and Clinical Biomedical Sciences (M.B., G.B., N.T., C.F.), Department of Clinical and Experimental Medicine, Thrombosis Centre (R.M., A.M.G., B.G., G.F.G., R.A.), and Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, Research Unit of Histology and Embryology (D.B.), University of Florence, Florence, Italy; and Don Carlo Gnocchi Foundation, Florence, Italy (A.M.G., G.F.G.).
Gian Franco
GF
Gensini
From the Department of Experimental and Clinical Biomedical Sciences (M.B., G.B., N.T., C.F.), Department of Clinical and Experimental Medicine, Thrombosis Centre (R.M., A.M.G., B.G., G.F.G., R.A.), and Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, Research Unit of Histology and Embryology (D.B.), University of Florence, Florence, Italy; and Don Carlo Gnocchi Foundation, Florence, Italy (A.M.G., G.F.G.).
Rosanna
R
Abbate
From the Department of Experimental and Clinical Biomedical Sciences (M.B., G.B., N.T., C.F.), Department of Clinical and Experimental Medicine, Thrombosis Centre (R.M., A.M.G., B.G., G.F.G., R.A.), and Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, Research Unit of Histology and Embryology (D.B.), University of Florence, Florence, Italy; and Don Carlo Gnocchi Foundation, Florence, Italy (A.M.G., G.F.G.). claudia.fiorillo@unifi.it.
Claudia
C
Fiorillo
D000368:Aged; D001777:Blood Coagulation; D016022:Case-Control Studies; D002942:Circular Dichroism; D005260:Female; D005340:Fibrinogen / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D005342:Fibrinolysis; D006801:Humans; D008297:Male; D046529:Microscopy, Electron, Transmission; D008857:Microscopy, Interference; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D062645:Percutaneous Coronary Intervention; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D050050:Protein Carbonylation; D017433:Protein Structure, Secondary; D013329:Structure-Activity Relationship; D013997:Time Factors
D010975:Platelet Aggregation Inhibitors; D005340:Fibrinogen
fibrinogen; myocardial infarction; oxidative stress