Effect of Human Milk Fortifier on the Immunodetection and Molecular Mass Profile of Transforming Growth Factor-Alpha

Abstract

Objective: To determine if the addition of human milk fortifier (HMF) affects the distribution, immunoreactivity, or molecular mass profile of transforming growth factor-α (TGF-α) within 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-α concentration was measured via radioimmunoassay in whole milk and its aqueous and fat fractions ± HMF. TGF-α molecular mass profiles of the samples (v/v) were measured via Western blotting. Results: TGF-α concentration (mean ± SD) in fortified whole milk (15.7 ± 7.1 pg/100 μl) vs. nonfortified whole milk (14.8 ± 8.0 pg/100 μl) and in the aqueous fraction of fortified (14.0 ± 2.7 pg/100 μl) vs. nonfortified (14.0 ± 3.5 pg/100 μl) did not differ statistically. There was, however, a marked decrease in the concentration of TGF-α in the fat fraction of fortified (30.6 ± 2.8 pg/100 μl) vs. nonfortified (98.0 ± 6.9 pg/100 μl) milk samples. Western blot for TGF-α 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 band, 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-α concentration and molecular mass profile. What effect this alteration in human milk biochemistry has on neonatal gut function remains unknown.

Host Factors in Amniotic Fluid and Breast Milk that Contribute to Gut Maturation

“…Mixing human milk with solutions of varying osmolality and protein concentration does not affect leukocyte viability or phagocytosis; however, what effect these solutions have on the macrophage state of activation and secretion of bioactive substances is not known. Adding cow milk-based fortifier to human milk does decrease the immunodetection of TGFα [145], and thus, there may be changes in the bioavailability of certain growth factors in vivo that have subtle but significant effects on gut function.…”