Human intestinal fatty acid binding protein: report of an assay with studies in normal volunteers and intestinal ischemia.
BACKGROUND
Human intestinal fatty acid binding protein (hIFABP) is a cytoplasmic protein of mature small intestinal epithelium. Work with the rat demonstrated that serum levels of IFABP correlated with early phases of intestinal mucosal injury. The aim of this study was to develop an assay for hIFABP and assess its usefulness as a marker for intestinal mucosal injury in human beings.


METHODS
Recombinant hIFABP (r-hIFABP) was used to produce rabbit anti-hIFABP. Specificity and avidity of binding were tested with immunoprecipitation and Scatchard analysis. r-hIFABP was labeled with 125I, and a competitive assay was developed. Urine and serum from normal volunteers and from patients with necrotizing enterocolitis (NEC), acute thromboembolic related intestinal ischemia, and systemic inflammatory response syndrome were tested for hIFABP.


RESULTS
Molecular weight was 10(-12) kd, limit of detection was 1.87 ng/ml, and no cross-reactivity occurred when tested against rat IFABP or human heart FABP. Mean levels of hIFABP (ng/ml) were controls (serum less than 1.87, urine less than 1.87), NEC (serum 14.7 ng/ml), intestinal ischemia (serum 50 ng/ml, urine 52.3 ng/ml), systemic inflammatory response syndrome (serum 5.3 ng/ml, urine 13.2 ng/ml).


CONCLUSIONS
This assay is quantitative for hIFABP in serum and urine. Results from both normal persons and those with various causes of intestinal ischemia parallel our previous findings in the rat. Preliminary findings suggest that hIFABP may serve as a diagnostic marker for early intestinal mucosal compromise and, in addition, that it should prove useful as a tool in developing rationale therapeutic regimens to treat these complex clinical problems.
Lieberman
J M
JM
Department of Organ Transplantation, Swedish Medical Center, Seattle, Wash. 98104, USA.
Sacchettini
J
J
Marks
C
C
Marks
W H
WH
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000918:Antibody Specificity; D001667:Binding, Competitive / Q000502:physiology; D001826:Body Fluids / Q000737:chemistry; D002352:Carrier Proteins / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D017091:Colitis, Ischemic / Q000378:metabolism*; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D006801:Humans; D007122:Immunoelectrophoresis; D007421:Intestine, Small / Q000098:blood supply / Q000737:chemistry / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D018996:Myelin P2 Protein / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D011817:Rabbits; D011863:Radioimmunoassay; D051381:Rats; D011994:Recombinant Proteins; D025521:Tumor Suppressor Proteins
D002352:Carrier Proteins; C107608:FABP7 protein, human; C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D007457:Iodine Radioisotopes; D018996:Myelin P2 Protein; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D025521:Tumor Suppressor Proteins