and H-FABP in acute ischaemic stroke and suggested that these
In the brain and intestine, brain-type fatty acid protein (B-FABP) and intestine-type fatty acid protein (I- FABP) are tissue-specific, but H-FABP and L-FABP are co- expressed.1
They may represent promising tools to improve patient care after kidney transplantation.38 Teratani et al.2 also reported that B-FABP is a sensitive marker for renal cell carcinoma (RCC).
They reported that B-FABP was expressed in carcinoma tissue, but not in the noncancerous parts of the kidney samples resected from patients with RCC.
The brain contains both H-FABP and B-FABP in specific regions.40,41 B-FABP and H-FABP are new potential markers for the detection of brain injury.1 Pelsers et al.42 have shown elevated serum levels of B-FABP and H-FABP in traumatic brain injury.
In line with our results, data from previous studies have shown that several members of the FABP family, including H-FABP (33), L-FABP (34), intestine-type FABP (I-FABP) (35), and brain-type FABP (B-FABP) (36), are present in the human bloodstream, presumably being released from the cells via direct diffusion.
 Nonstandard abbreviations: A-, H-, L-, E-, I-, and B-FABP, adipocyte, heart-type, liver-type, keratinocyte, intestine-type, and brain-type fatty acid-binding protein, respectively; apo E, apolipoprotein E; 2-DE, 2-dimensional gel electrophoresis; MS/MS, tandem mass spectrometry; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; BMI, body mass index; and HOMA, homeostasis model assessment.
B-FABP and H-FABP are members of a family of nine distinct FABP types, each named after the tissue in which it was first detected (16).
The aim of our study was to investigate the tissue distribution and concentrations of B-FABP and H-FABP in human brain and to study the potential of these proteins as serum markers for the detection of brain injury in patients.
To determine the biological variation for circulating B-FABP and to establish a reference interval, we obtained plasma samples (EDTA) from 80 healthy individuals (40 males and 40 females; age ranges, 21-30, 31-40, 41-50, 51-60, and 61-70 years; n = 8 for each group) visiting the blood bank of Litige to study the influence of age and gender, and from another 12 healthy individuals (citrated plasma; 6 males and 6 females; age range, 19-27 years) from the Maastricht University student population to study the influence of circadian rhythm (21).
Production of recombinant B-FABP and antibodies against B-FABP.
To test the specificity and cross-reactivity of the antibodies used in the ELISA, we subjected samples containing B- and H-FABP (both 1 [micro]g and 10 [micro]g in each case) to 13.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, blotted the gels on a HyBond nitrocellulose membrane (Amersham Biosciences), and detected the FABPs with purified polyclonal antibodies against B-FABP and with monoclonal antibodies against H-FABP (67D3 and 66E2 as capture and detector antibodies, respectively, in the H-FABP ELISA; HyCult Biotechnology) (23,24).