Plasma soluble α-klotho protein levels in premature and term neonates: correlations with growth and metabolic parameters.
OBJECTIVE
α-Klotho (α-KL), a protein with antiaging properties, regulates phosphate, calcium, and bone metabolism, induces resistance to oxidative stress, and may participate in insulin signaling. The role of α-KL in neonates, known to be prone to metabolic disturbances and oxidative stress, is not known. The aim of this study was to evaluate circulating soluble α-KL concentrations in preterm and full-term neonates and unravel possible correlations with growth, metabolism, and indices of oxidative stress.


METHODS
Prospective study.


METHODS
Plasma-soluble α-KL levels were determined by specific ELISA in 50 healthy neonates (25 preterm, mean (s.d.) gestational age (GA) 33.7 (1.1) weeks, and 25 full-term infants) at days 14 and 28 of life. Associations of α-KL with anthropometric, metabolic parameters, and indices of oxidative stress were examined.


RESULTS
α-KL levels were significantly higher in full-term than in preterm infants at both days 14 (1099 (480) pg/ml vs 884 (239) pg/ml respectively; P<0.05) and 28 (1277 (444) pg/ml vs 983 (264) pg/ml respectively; P<0.01). In both preterm and full-term infants, α-KL levels increased significantly from day 14 to 28 of life (P<0.001). Circulating α-KL concentrations correlated with GA (β=0.32, P=0.001), body weight (β=0.34, P=0.001), body length (β=0.33, P=0.001), 1,25-dihydroxy-vitamin D level (β=0.24, P<0.05), and malondialdehyde level (β=0.20, P<0.05) but not with glucose, insulin, or homeostasis model assessment index of insulin resistance values.


CONCLUSIONS
Soluble α-KL levels rise as GA and postnatal age advance in neonates and may have an impact on vitamin D metabolism and oxidative stress. Whether α-KL may have a role in the regulation of infants' growth should be further studied.
First Department of Pediatrics, Athens University Medical School, Athens, Greece. siahan@med.uoa.gr
Tania
T
Siahanidou
Maria
M
Garatzioti
Christina
C
Lazaropoulou
Georgia
G
Kourlaba
Ioannis
I
Papassotiriou
Tomoshige
T
Kino
Akihiro
A
Imura
Yo-ichi
Y
Nabeshima
George
G
Chrousos
D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D002657:Child Development / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005966:Glucuronidase / Q000097:blood*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood* / Q000254:growth & development*; D000090265:Klotho Proteins; D008297:Male; D018384:Oxidative Stress / Q000502:physiology*
D015415:Biomarkers; D005966:Glucuronidase; D000090265:Klotho Proteins