Human heart fatty-acid binding

T. M. O Regan, M. Pravda, C.K. O Sullivan and G.G. Guilbault, Development of a disposable immunosensor for the detection of human heart fatty-acid binding protein in human whole blood using screen-printed carbon electrodes, Talanta, 57 (2002) 501-510. 

Two immunosensors developed by O Regan et al. [89,90] have demonstrated their usefulness for the early assessment of acute myocardial infarction (AMI). Human heart fatty-acid binding protein (H-FABP) is a biochemical marker for the early assessment of AMI. The authors constructed an amperometric immunosensor for the rapid detection of H-FABP in whole blood. The sensor is based on a one-step, direct sandwich assay in which the analyte and an alkaline phosphatase (AP) labelled antibody are simultaneously added to the immobilized primary antibody, using two distinct monoclonal mouse anti-human H-FABP antibodies. The substrate p-amino-phenyl phosphate is converted to p-aminophenol by AP, and the current generated by its subsequent oxidation at +300 mV vs. Ag/AgCl is measured. The total assay time is 50 min, and the standard curve was linear between 4 and 250 ng ml . The intra- and inter-assay coefficients of variation were below 9%. No cross-reactivity of the antibodies was found with other early cardiac markers, and endogenous substances in whole blood did not have an... 

Although there are published antibody-based methods for many of the kidney-specific proteins listed above, antibodies are not commercially available currently for many of them (specifically, KIM-1, CYR-61 and Pap Al). Where the antibodies are readily available, cross-reactivity across species has not always been established (these have in general been used only in human and/or rat). Heart and kidney specific isoforms of fatty acid binding protein exist that may cross-react in some species with the LFBP antibodies additionally, a-2 x-globulin, a normal component of male rat urine, is homologous to K-FABP and may cross-react with the antibodies to LFBP (for reviews see Emeigh Hart, 2005, Emeigh Hart and Kinter 2005). 

Fatty acid binding protein (FABP3) is a cytosolic protein recently reported to be more sensitive for detection of cardiac injury in humans with myocardial infarct or congestive heart failure (Mion et al. 2007 Niizeki et al. 2007). Flowever, FABP3 is also found, although in much lower concentrations, in muscle, brain, and kidney. As for CK and LD, its occurrence in skeletal muscle substantially diminishes its value as a cardiac biomarker because of the higher and variable background of mild skeletal muscle injury in laboratory animals. Its use as a cardiac biomarker would require exclusion of muscle injury and renal disease. 

Maatman RG, van de Westerlo EM, van Kuppevelt TH, Veerkamp JH. (1992) Molecular identification of the hver- and the heart-type fatty acid-binding proteins in human and rat kidney. Use of the reverse transcriptase polymerase chain reaction. Biochem J. 288(Pt l) 285-290. 

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