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Plasma leptin in infants: relations to birth weight and weight loss
G Marchini1, G Fried, E Ostlund
1Department of Woman and Child Health, Karolinska Institute, Karolinska Hospital, Stockholm, Sweden.
Insights
Infant plasma leptin levels correlate with birth weight and adipose tissue. Leptin levels decrease with normal neonatal weight loss, indicating its relation to nutritional status from fetal development through infancy.
Area of Science:
- Endocrinology
- Neonatal Physiology
- Nutritional Science
Background:
- Leptin, a hormone from adipose tissue, regulates body weight.
- Leptin levels are elevated in obesity and reduced after fasting in adults.
- This study explored leptin's role in infant birth weight and neonatal weight changes.
Purpose of the Study:
- To investigate the relationship between plasma leptin levels and infant birth weight.
- To determine if plasma leptin levels decrease with physiological neonatal weight loss.
Main Methods:
- Plasma leptin levels were measured in cord blood of infants categorized as large (LGA), small (SGA), and appropriate (AGA) for gestational age.
- Leptin levels were also assessed in exclusively breastfed AGA infants during the first four postnatal days.
- Radioimmunoassay was used to quantify plasma leptin concentrations.
Main Results:
- Cord blood leptin levels were higher in LGA infants and lower in SGA infants compared to AGA infants.
- A positive correlation was observed between cord blood leptin levels and infant birth weight (r=0.76) and BMI (r=0.63).
- A 3-6% physiological weight reduction in the first four days postpartum was associated with a 26% decrease in plasma leptin.
Conclusions:
- Plasma leptin levels are strongly linked to adipose tissue mass in newborns.
- Leptin levels decrease with initial physiological weight loss in neonates.
- These findings suggest leptin reflects nutritional status during fetal and neonatal periods.
Background:
The hormone leptin, produced in the adipose tissue, is involved in the regulation of body weight. The release of the hormone is increased in obese adults and decreased after fasting in human adults. This study investigated whether the plasma leptin level was related to the infant's birth weight and whether the level was reduced in connection with the physiological weight loss during the neonatal period.
Methods:
We measured the plasma leptin level in cord blood from infants who were large for gestational age (LGA) (n = 15), small for gestational age (SGA) (n = 16), and appropriate for gestational age (AGA) (n = 38). AGA infants (n = 120), who were exclusively breastfed, were also studied during their first 4 postnatal days in a cross-sectional method. One blood sample was collected before breastfeeding from each infant. Plasma leptin concentrations were determined by radioimmunoassay.
Results:
The median (range) concentration of leptin from cord blood was increased in LGA infants and decreased in SGA infants compared with the level in AGA infants. There was a positive correlation between the log of the plasma leptin level in cord blood and both the infant's birth weight (r = 0.76; n = 69) and the body mass index (r = 0.63; n = 69). The normal 3% to 6% weight reduction that occurs during the first 4 postnatal days was associated with a 26% decrease in the plasma leptin level in healthy breastfed infants.
Conclusions:
The plasma leptin level is highly correlated to the size of adipose tissue mass and decreases in connection with the initial physiological weight loss in newborn infants. These data provide evidence that leptin is highly related to the nutritional status already during the fetal and neonatal periods.