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) 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-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 microl) vs. nonfortified whole milk (14.8 +/- 8.0 pg/100 microl) and in the aqueous fraction of fortified (14.0 +/- 2.7 pg/100 microl) vs. nonfortified (14.0 +/- 3.5 pg/100 microl) 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 microl) vs. nonfortified (98.0 +/- 6.9 pg/100 microl) 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 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-alpha concentration and molecular mass profile. What effect this alteration in human milk biochemistry has on neonatal gut function remains unknown.
Lessaris
K J
KJ
Human Lactation Research and Education Center, Department of Pediatrics, Division of Neonatology, Children's Hospital, Medical University of South Carolina, Charleston 29425, USA.
Forsythe
D W
DW
Wagner
C L
CL
D000818:Animals; D015153:Blotting, Western; D005260:Female; D005527:Food, Fortified; D006801:Humans; D007774:Lactation; D008895:Milk, Human / Q000737:chemistry*; D008970:Molecular Weight; D011863:Radioimmunoassay; D016211:Transforming Growth Factor alpha / Q000032:analysis* / Q000737:chemistry*
D016211:Transforming Growth Factor alpha