title: Concentrations of thioredoxin, a redox-regulating protein, in umbilical cord blood and breast milk.
abstract: Growing evidence indicates that oxidative stress occurs during the fetal-to-neonatal transition. Such stress plays an important role in the pathogenesis of many neonatal diseases. Thioredoxin (TRX), a redox-regulating protein with antioxidant activity, is induced in various cells against oxidative stress and is secreted extracellularly. This study was undertaken to examine the clinical and biological importance of TRX in the perinatal setting. We measured concentrations of TRX in umbilical cord blood and breast milk using a sandwich ELISA. Our study demonstrated that concentrations of TRX in umbilical cord blood were six to seven times higher than those in blood of healthy adults. This study also showed that umbilical concentrations of TRX were correlated significantly with the extent of prematurity of the newborn, and that they were elevated significantly in newborns of mothers with preeclampsia compared to those of mothers without preeclampsia. In contrast, concentrations of coenzyme Q(10) and vitamin E in umbilical blood were lower than adult blood levels. Breast milk concentrations of TRX during the early postpartum period were seven to eight times higher than those in blood of lactating women. Those of the coenzyme Q(10) were lower than adult blood levels, while those of vitamin E were comparable to adult blood levels. Our findings suggest that the systemic release of TRX is enhanced at birth, and that early breast milk is a rich source of this protein. Consequent high levels of TRX in newborns may provide a unique protective mechanism that allows the maintenance of redox balance during the fetal-to-neonatal transition.
authors.affiliation: Department of Pediatrics, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Todoroki
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Tsukahara
authors.forename: Yusei
authors.initials: Y
authors.lastname: Ohshima
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Shukunami
authors.forename: Koji
authors.initials: K
authors.lastname: Nishijima
authors.forename: Fumikazu
authors.initials: F
authors.lastname: Kotsuji
authors.forename: Atsuko
authors.initials: A
authors.lastname: Hata
authors.forename: Kenkou
authors.initials: K
authors.lastname: Kasuga
authors.forename: Kyouichi
authors.initials: K
authors.lastname: Sekine
authors.forename: Hajime
authors.initials: H
authors.lastname: Nakamura
authors.forename: Junji
authors.initials: J
authors.lastname: Yodoi
authors.forename: Mitsufumi
authors.initials: M
authors.lastname: Mayumi
mesh_terms: D000328:Adult; D003067:Coenzymes; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D005333:Fetus / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000378:metabolism; D008297:Male; D008895:Milk, Human / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011225:Pre-Eclampsia / Q000378:metabolism; D011247:Pregnancy; D013879:Thioredoxins / Q000378:metabolism*; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000378:metabolism; D014810:Vitamin E / Q000378:metabolism
chemical_list: D003067:Coenzymes; D014451:Ubiquinone; D014810:Vitamin E; D013879:Thioredoxins; C024989:coenzyme Q10