Fatty acid-binding proteins (FABPs) are a group of small (12-15 kDa) cytoplasmic proteins that are abundant in tissues with active fatty acid metabolism. They participate in the intracellular transportation of long-chain fatty acids. The heart-type FABP (H-FABP) is composed of 132 amino acids and it is one of the most abundant proteins in the myocardial tissue that constitutes 5-15% of the cytoplasmic proteins in the human heart.
H-FABP in diagnostics
H-FABP is one of the early markers of acute coronary syndrome. Its specificity is much higher than that of myoglobin, which is another early marker of cardiac injury (1). Following an acute cardiac event, the level of H-FABP rapidly increases in the blood. It can be detected much earlier than cardiac troponins, which are the most specific biomarkers of myocardial infarction. H-FABP concentration peaks within six hours and returns back to normal after 12-24 hours. Following this it loses its clinical value.
H-FABP can provide valuable information to support the diagnosis of patients suspected of having an acute cardiac event. H-FABP alone is not sufficiently specific as a marker for cardiac injuries since it is also expressed in other tissues besides the heart. Furthermore, its diagnostic window is not as wide as that of troponins, for example. However, as part of a multi-marker panel, H-FABP brings additional value in terms of supporting clinical diagnostics decisions. It is applied in emergency triage of patients with acute coronary syndromes (2). H-FABP measurements could also be used to identify patients with a low risk of acute myocardial infarction (AMI) and consequently accelerate their discharge from hospital (3).
H-FABP has also been identified as a biomarker that is useful in regard to the prediction of adverse prognosis in patients with pulmonary embolism. European Society of Cardiology guidelines on the diagnosis and management of acute pulmonary embolism (4) list H-FABP as one of the biomarkers that could be used for risk stratification in confirmed pulmonary embolism cases.