Determination of alpha1-proteinase inhibitor by a new enzyme linked immunosorbant assay in feces, serum and an enterocyte-like cell line.
Although alpha(1)-proteinase inhibitor (alpha(1)-PI), the main serine proteinase inhibitor in human plasma, is predominantly liver-derived, the proof of fecal alpha(1)-PI is a maker for intestinal protein loss. Furthermore, alpha(1)-PI is synthesized locally by human intestinal epithelial cell lines (e. g. Caco-2). Therefore, we investigated the diagnostic value of a new enzyme-linked immunosorbent assay (ELISA) to detect alpha(1)-PI in serum, feces, and Caco-2 supernatants in comparison with radial immunodiffusion (RID). alpha(1)-PI concentrations assessed by ELISA were on an average 30 % higher than those measured by RID. Only the ELISA system detected alpha(1)-PI in supernatants of Caco-2 cells. Our data imply first that this ELISA system is more sensitive to assess alpha(1)-PI than other methods, and second that it obviously determines locally synthesized alpha(1)-PI which can not be liver-derived. However, further examinations are necessary to distinguish between enterocyte-derived or systemic alpha(1)-PI and its diagnostic relevance in bowel disease.
Faust
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2nd Department of Internal Medicine, Johann Wolfgang Goethe University, Frankfurt/Main, Germany. J.Stein@em.uni-frankfurt.de
Spirchez
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Armbruster
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Stein
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D000293:Adolescent; D000328:Adult; D000368:Aged; D018938:Caco-2 Cells; D002648:Child; D003937:Diagnosis, Differential; D020895:Enterocytes / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D005779:Immunodiffusion; D008286:Malabsorption Syndromes / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D000515:alpha 1-Antitrypsin / Q000032:analysis*
D000515:alpha 1-Antitrypsin