Fibronectin as an Immunohistochemical Marker for Postmortem Diagnosis of Myocardial Infarction

             http://www.mathewsopenaccess.com/immunology-allergy-current-issue.html

Acute myocardial infarction is sometimes a diagnostic dilemma in forensic pathology. Our aim is to evaluate the efficacy of fibronectin by immunohistochemical methods for diagnosis of early myocardial infarction in heart autopsies.Three groups of cases selected from autopsied hearts submitted to the pathology department of legal medicine organization of Iran during years 2004-2007 which included 15 cases of definite myocardial infarction (positive control group), 18 cases of noncardiac death (negative control group) and 26 cases suspicious of myocardial infarction based on clinical presentation just before death, presence of marked stenosis in at least one major coronary artery and exclusion of other causes of death (suspicious group). Fibronectin staining was performed on sections prepared from all of the cases. With our proposed cut off value for fibronectin staining the sensitivity and specificity of this marker are 93.3% and 94.4%, respectively. This marker could also support the occurrence of myocardial infarction in 42% of our suspicious cases.We conclude that in spite of usefulness of this marker for detection of myocardial infarction, the results should be interpreted with caution.

Diagnosis of acute myocardial infarction is a challenging issue in forensic pathology. In autopsied hearts macroscopic findings of myocardial infarction accompanied by microscopic confirmation are the gold standards for diagnosis. However, the development of these changes requires time and in real practice we rarely are fortunate enough to see the typical cases. In most instances nothing other than significant narrowing of coronary arteries is found in favor of myocardial infarction. Use of an ancillary method is highly advocated in these situations. Application of triphenyltetrazolium chloride to the fresh myocardium, electron microscopy and some immunohistochemical markers including myoglobin, fatty acid binding protein (FABP), troponin, desmin, fibronectin, fibrinogen, C5b-9 and vascular endothelial growth factor (VEGF) are among many different diagnostic methods which have been used to address this diagnostic dilemma. The electron microscopy is not available in every pathology laboratory and requires comprehensive expertise. The triphenyltetrazolium chloride method requires fresh tissue and a great deal of suspicion at the time of autopsy. The immunohistochemical studies are, however, promising alternatives. The aim of the current study is to evaluate the diagnostic power of one of these immunohistochemical markers, the fibronectin, in suspicious cases of myocardial infarction.

Fibronectin as an Immunohistochemical Marker for Postmortem Diagnosis of Myocardial Infarction

                http://mathewsopenaccess.com/immunology-allergy-current-issue.html

Acute myocardial infarction is sometimes a diagnostic dilemma in forensic pathology. Our aim is to evaluate the efficacy of fibronectin by immunohistochemical methods for diagnosis of early myocardial infarction in heart autopsies.Three groups of cases selected from autopsied hearts submitted to the pathology department of legal medicine organization of Iran during years 2004-2007 which included 15 cases of definite myocardial infarction (positive control group), 18 cases of noncardiac death (negative control group) and 26 cases suspicious of myocardial infarction based on clinical presentation just before death, presence of marked stenosis in at least one major coronary artery and exclusion of other causes of death (suspicious group). Fibronectin staining was performed on sections prepared from all of the cases. With our proposed cut off value for fibronectin staining the sensitivity and specificity of this marker are 93.3% and 94.4%, respectively. This marker could also support the occurrence of myocardial infarction in 42% of our suspicious cases.We conclude that in spite of usefulness of this marker for detection of myocardial infarction, the results should be interpreted with caution. 

Diagnosis of acute myocardial infarction is a challenging issue in forensic pathology. In autopsied hearts macroscopic findings of myocardial infarction accompanied by microscopic confirmation are the gold standards for diagnosis. However, the development of these changes requires time and in real practice we rarely are fortunate enough to see the typical cases. In most instances nothing other than significant narrowing of coronary arteries is found in favor of myocardial infarction. Use of an ancillary method is highly advocated in these situations. Application of triphenyltetrazolium chloride to the fresh myocardium, electron microscopy and some immunohistochemical markers including myoglobin, fatty acid binding protein (FABP), troponin, desmin, fibronectin, fibrinogen, C5b-9 and vascular endothelial growth factor (VEGF) are among many different diagnostic methods which have been used to address this diagnostic dilemma. The electron microscopy is not available in every pathology laboratory and requires comprehensive expertise. The triphenyltetrazolium chloride method requires fresh tissue and a great deal of suspicion at the time of autopsy. The immunohistochemical studies are, however, promising alternatives. The aim of the current study is to evaluate the diagnostic power of one of these immunohistochemical markers, the fibronectin, in suspicious cases of myocardial infarction.

The autopsied hearts were fixed in 10% formalin and tissue sections processed routinely. The processed sections were embedded in paraffin block and from which 4 micrometerthick slide sections were prepared and transferred to sialinized microscopic slides. The slide sections incubated for one hour in 60˚C and then deparaffinized in two changes of xylene each for 5 minutes. Then the endogenous peroxidase activity was blocked by incubation for 15 minutes using 3% hydrogen peroxide in methanol. After washing with Tris-buffered saline (TBS), the slides were incubated for 35 minutes by the primary antibody (1/1000 dilution of a proprietary Rabbit anti human fibronectin, monoclonal antibody, Dakocytomation, Denmark). Next the unbound antibody was washed away by floating the slides in three changes of TBS, three minutes each. Finally, the potentially bounded antibodies were developed and detected by LSAB2 System-HRP detection kit (Dakocytomation, Denmark) according to the manufacturer’s instructions.