Received on November 1, 2005
Accepted on July 3, 2006

Endocrinology and Metabolism

Adiponectin, Adipocyte Fatty Acid Binding Protein, and Epidermal Fatty Acid Binding Protein: Proteins Newly Identified in Human Breast Milk

Jií Bronsk ¹, Michal Karpíek ², Eva Bronská ³, Marta Pechová ⁴, Barbora Janíková ⁵, Hana Kotolová ², David Stejskal ⁶, Richard Pra ⁴, Jií Nevoral ⁷

¹ Pediatric Gastroenterology Unit, Pediatric Clinic, 2nd Medical Faculty, Charles University and University Hospital Motol, Prague, Czech Republic, and Department of Clinical Biochemistry and Pathobiochemistry, 2nd Medical Faculty, Charles University and University Hospital Motol, Prague, Czech Republic
² Department of Human Pharmacology and Toxicology, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic
³ National Institute of Public Health and 3rd Medical Faculty, Charles University and University Hospital Bulovka, Prague, Czech Republic
⁴ Department of Clinical Biochemistry and Pathobiochemistry, 2nd Medical Faculty, Charles University and University Hospital Motol, Prague, Czech Republic
⁵ Department of Neonatology, 2nd Medical Faculty, Charles University and University Hospital Motol, Prague, Czech Republic
⁶ Department of Laboratory Medicine, Hospital ternberk, ternberk, Czech Republic
⁷ Pediatric Gastroenterology Unit, Pediatric Clinic, 2nd Medical Faculty, Charles University and University Hospital Motol, Prague, Czech Republic

Background: Breastfeeding may protect children from developing metabolic syndrome and other diseases later in life. We investigated novel proteins in human breast milk that might play a role in this process.

Methods: We used ELISA to measure adiponectin, adipocyte and epidermal fatty acid binding proteins (AFABP, EFABP) and leptin concentrations in human breast milk obtained from 59 mothers 48 h after initiation of lactation. Using a questionnaire and medical reports, we collected information about the mothers and newborns.

Results: Mean (SE) adiponectin concentrations in breast milk were 13.7 (0.8), range 3.9-30.4 µg/L; AFABP concentrations 26.7 (4.4), range 1.2-137.0 µg/L; EFABP concentrations 18.1 (1.4), range 0.8-47.0 µg/L; and leptin concentrations 0.50 (0.05), range 0-1.37 µg/L. We found a significant correlation between AFABP and EFABP concentrations (r = 0.593, P <0.0001). Maternal EFABP concentrations were significantly higher in mothers who delivered boys than in those who delivered girls [21.7 (2.3) vs 15.4 (1.7) ug/L, P = 0.028] and correlated with newborn birth weight (r = 0.266, P = 0.045). Maternal leptin correlated with body weight before pregnancy (r = 0.272, P = 0.043) and at delivery (r = 0.370, P = 0.005), body mass index before pregnancy (r = 0.397, P = 0.003) and at delivery (r = 0.498, P <0.0001), body weight gain during pregnancy (r = 0.267, P = 0.047), and newborn gestational age (r = 0.266, P = 0.048). Leptin was significantly lower in mothers who delivered preterm vs term babies [0.30 (0.09) vs 0.60 (0.05) ug/L, P = 0.026].

Conclusions: Concentrations of adiponectin, AFABP, and EFABP in human breast milk are related to nutritional variables of mothers and newborns and thus may play a role in the protective effects of breastfeeding.