Effect of human milk fortifier on the immunodetection and molecular mass profile of transforming growth factor-alpha

Objective: To determine if the addition of human milk fortifier (HMF) affects the distribution, immunoreactivity, or molecular mass profile of transforming growth factor alpha (TGF-alpha) with in the compartments of human milk. Methods: Fifteen milk samples were obtained, Each sample was divided into two aliquots; a powdered HMF was added to the first aliquot. TGF-alpha concentration was measured via radioimmunoassay in whole milk and its aqueous and fat fractions +/- HMF, TGF-alpha molecular mass profiles of the samples (v/v) were measured via Western blotting. Results: TGF-alpha concentration (mean +/- SD) in fortified whole milk (15.7 +/- 7.1 pg/100 mu l) vs, nonfortified whole milk (14.8 +/- 8.0 pg/100 mu l) and in the aqueous fraction of fortified (14.0 +/- 2.7 pg/100 mu l) vs, nonfortified (14.0 +/- 3.5 pg1100 mu l) did not differ statistically. There was, however, a marked decrease in the concentration of TGF-alpha in the fat fraction of fortified (30.6 +/- 2.8 pg/100 mu l) vs, nonfortified (98.0 +/- 6.9 pg/100 mu l) milk samples. Western blot for TGF-alpha in whole milk and its separated fractions revealed characteristic bands at 6.5, 12-16, 22, 26-30 and 46 kD, HMF alone and HMF with sodium taurocholate had a prominent band at 18 kD and fainter bands at 6.5, 26-30, and 46 kD, While whole and aqueous milk samples with HMF also consistently showed the 18-kD hand, in 8/15 fat fraction samples with HMF the 18-kD band was nondetectable and was only faintly detectable in the remaining 7/15 samples. Conclusions: It appears that HMF differentially alters the biochemical profile of human milk with regard to TGF-alpha concentration and molecular mass profile, What effect this alteration in human milk biochemistry has on neonatal gut function remains unknown, Copyright (C) 2000 S. Karger AG, Basel .