High serum leptin levels in infancy can potentially predict obesity in childhood, especially in formula-fed infants.

AIM: To investigate serum leptin levels in breast-fed and formula-fed infants in infancy and their possible relationship to body mass index (BMI) in childhood. METHODS: We enrolled 237 healthy term infants between September 2000 and April 2004 and tested their serum leptin levels, took anthropometric measurements and calculated BMI. A follow-up study was carried out to evaluate the BMI of 89 of these infants in childhood, in relation to their serum leptin levels in infancy, at a median (interquartile range) age of 8.8 years (7.8-10.2). The statistical significance of this multivariate analysis was set at p < 0.05. RESULTS: Breast-fed infants had significantly higher serum leptin levels than formula-fed ones (p < 0.05). Children who were formula-fed in infancy had a significantly higher BMI, at follow-up, than those who were breast-fed (p < 0.001). Furthermore, we identified a leptin cut-off value of 2.7 ng/mL, below which infants had a higher BMI in childhood. CONCLUSION: A higher leptin level in infancy may be inversely associated with BMI in childhood, suggesting that this hormone in infancy is a potential predictor of obesity in later life. Further investigation is required to be conclusive and to confirm our empirical evidence.

Evaluation of leptin in breast milk, lactating mothers and their infants.

BACKGROUND/OBJECTIVES: Leptin is present in human milk, but it is not clear what the relationship between breast milk (BM) leptin levels and maternal and infant serum leptin concentrations is. The objective of this study was to evaluate the leptin concentration in BM and to investigate its relationship with infants' and mothers' anthropometric parameters and with serum leptin concentration in breast-fed (BF) infants and lactating mothers. SUBJECTS/METHODS: We enrolled 36 adequate for gestational age healthy, exclusively BF, term infants aged <6 months. Leptin concentration in serum and BM was determined by radioimmunoassay (RIA) test (human-leptin-RIA-sensitive, Mediagnost). Infants' and mothers' weights, lengths and body mass indexes (BMI) were measured. RESULTS: The median leptin concentration was 3.42 ng/ml (interquartile range (IR): 2.65) in BF infants' serum, 3.02 ng/ml (IR: 2.85) in mothers' serum (n=17) and 0.51 ng/ml (IR: 0.34) in BM (n=24). BM leptin concentrations were significantly lower than serum BF infant (P<0.001) and maternal (P<0.001) leptin levels. Infant serum leptin concentration correlated positively with infant weight (r=0.437, P=0.008) and BMI (r=0.561, P=0.004). Mother serum leptin levels correlated positively with weight (r=0.755, P<0.001) and BMI (r=0.661, P=0.007). No correlations were found between BM leptin and serum leptin concentrations in BF infants and mothers. CONCLUSIONS: We confirmed the presence of leptin in BM at a lower concentration than that found in infant and lactating mother serum. We observed a positive correlation between serum leptin levels in BF infants and their growth parameters.

[Mycoplasma pneumoniae is not a respiratory pathogen only: two case reports of ''atypical'' clinical presentations]. / Il Mycoplasma pneumoniae non è solo un patogeno respiratorio: presentazione di due casi con manifestazioni ''atipiche''.

Mycoplasma pneumoniae is a common intracellular pathogen, which is responsible for infections of the respiratory tract, particularly in patients between 5 and 30 years of age. Nevertheless, there is increasing evidence that Mycoplasma pneumoniae plays a role in determining clinical presentations different from the respiratory ones. Among extra pulmonary complications skin eruptions are more frequent than others, even with severe clinical features such as Stevens Johnson syndrome. It is important to note that dermatological involvement can occur before, during or after the appearance of respiratory symptoms or without them. We report two patients whose onset of symptoms was not a respiratory tract disease, as usual in Mycoplasma pneumoniae infections, but prolonged and high grade fever with a relevant skin involvement pointing out the importance of researching Mycoplasma pneumoniae in the pathogenesis of peculiar clinical features. The first patient is a 4-year-old boy with signs of Stevens Johnson syndrome while the second patient is a 16-year-old girl with red-purple maculae on both legs and arms; in both cases we detected Mycoplasma IgM antibodies as a part of differential diagnosis. We discuss below the immunological mechanism by which Mycoplasma pneumoniae can determine the clinical features shown by our patients.

Ghrelin, motilin, insulin concentration in healthy infants in the first months of life: relation to fasting time and anthropometry.

AIMS: This study aimed to investigate: (i) the relation between fasting time and serum ghrelin, motilin and insulin concentrations and (ii) the correlations between these hormones and anthropometrical parameters of infants in the first 18 months of life. PATIENT AND METHODS: A cross-sectional study on 62 term infants was performed. Blood samples for hormonal assay were obtained at least 1 h after feeding. Weight, length and head circumference were recorded. Plasma ghrelin, motilin and insulin concentrations were determined by radioimmunoassay. RESULTS: Ghrelin and motilin had a significant direct correlation with fasting time (r = 0.447; P < 0.001 and r = 0.36; P = 0.004, respectively). We observed a negative influence of insulin on ghrelin levels (beta = -0.32; P = 0.036). Plasma ghrelin levels correlated significantly with age (r = 0.45, P < 0.001), weight (r = 0.31, P = 0.013), head circumference (r = 0.35, P = 0.006) and length (r = 0.39, P = 0.001). A significant correlation emerged between motilin and age (r = 0.45, P < 0.001), weight (r = 0.43, P = 0.001), head circumference (r = 0.47, P < 0.001) and length (r = 0.48, P < 0.001). CONCLUSIONS: Fasting influence on serum ghrelin concentration confirms the role of this hormone as a physiological meal initiator also in infancy. The correlation between ghrelin, anthropometrical parameters and age supports the hypothesis that this hormone could exert an important influence on growth in the first months of life. Considering motilin, age and weight might play a role in determining its secretion; motilin could be considered one of the numerous factors involved in long-term regulation of energy balance.

Serum ghrelin concentration and weight gain in healthy term infants in the first year of life.

OBJECTIVES: Ghrelin, a recently discovered hormone mainly secreted by the stomach, has several metabolic functions including regulation of food intake, energy homeostasis and body weight. There are few studies on this hormone in healthy infants during the first year of life. The aim of this study was to examine the correlations between ghrelin and weight gain in healthy term infants in the first year of life. METHODS: 104 healthy term infants aged 0 to 12 months were included in a cross-sectional study. Anthropometric measurements were assessed and mean weight gain was calculated. Serum ghrelin concentrations have been determined at least 3 hours after feeding by radioimmunoassay test. RESULTS: Ghrelin concentrations were correlated negatively to weight gain (r=-0.302; P=0.003) and positively to age (r = 0.412; P < 0.001), weight (r = 0.374; P < 0.001) and length (r=0.387; P<0.001). In breastfed infants a statistically significant negative correlation between ghrelin concentration and infant weight gain (r=-0.407; P=0.001) was observed, whereas in formula-fed infants this correlation was not statistically significant (r=-0.067; P=0.719). CONCLUSIONS: The negative correlation observed between ghrelin concentration and infant weight gain suggests that ghrelin might also play a role in the regulation of body weight in healthy infants with a physiologic energy balance. Further studies are needed to clarify how ghrelin might be involved in both short-term and long-term energy balance.