Adiponectin and brain natriuretic peptide relationship in newborns, infants and children

Purpose: Adiponectin (ADN), a cytokine secreted mainly by adipose tissue, regulates lipid and glucose metabolism, affects foetal development, exerts anti-inflammatory and anti-atherogenic effects. Besides the role as biomarker of cardiac function, brain natriuretic peptide (BNP) regulates ADN production by human adipocytes and a positive correlation between ADN and BNP levels was found in different patho-physiological conditions. In order to clarify the underlying mechanisms, we aimed at evaluating the relationships between ADN and BNP in children, known to have higher levels of BNP compared to adults. Methods: Plasma ADN and BNP was measured in 81 apparently healthy children divided into: 31 newborns (0-3 days), 22 neonates (3-30 days), 20 infants (1-12 months) and 8 infants (1-12 years). Blood was collected from healthy newborns and infants who underwent routine screening for genetic disorder (for newborns) or an endocrine work-up (for infants). All newborns were delivered at term and presented at birth with body weight ranging from 2.5-4.1 kg and an Apgar score>=8. A group of 33 healthy adult subjects (25-60 years) was also studied. Plasma ADN was measured by a specific ELISA and BNP by a fully automated Access platform. Results: ADN levels were two or thee fold higher in neonates than adults, showing the highest levels in 1 month of life [newborns 3 days of life: 27.55 mg/mL (18.26-34.44), median, 25°-75° percentiles; neonates 1 month: 28.27 mg/mL (20.39-40.33)], with a progressive decline in the next months/years [infants up to 1 year: 22.16 mg/mL (14.65-37.38); infant, ranging from 1 to 12 years: 12.92 mg/mL (8.95-20.56); adults: 6.13 mg/mL (4.73-8.13)] (p<0.001 newborns, neonates and infants up to 1 years vs. all other groups). BNP was significantly higher in the group of newborns up 3 days of life [175 pg/mL (131-289)], compared with the other groups (p<0.0001). In children, ADN levels were positively related to birthweight (Sperman's rho=0.420, p=0.006) and to BNP (Sperman's rho=0.312, p=0.011). Conclusion: Circulating ADN and BNP were higher in newborns than in adults, decreasing progressively with the age. The positive correlation between ADN and BNP in healthy children, known to have a different distribution of fat mass, appears to confirm their relationship found in the adults.