Growth factors and adipocytokines in prepubertal children born small for gestational age: relation to insulin resistance.

OBJECTIVE: The aim of this study was to test whether being born small for gestational age (SGA) has an impact on adiponectin and leptin levels and the IGF system in relation to insulin sensitivity, taking into consideration the severity of growth restriction. RESEARCH DESIGN AND METHODS: Serum levels of adiponectin, leptin, fasting glucose, fasting insulin (I(F)), the homeostasis model assessment insulin resistance index (HOMA-IR), IGF-1, free IGF-1, IGF-binding protein (IGFBP)-1 and -3, total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides were evaluated in 57 children at age 4-10 years. Of these, 32 had been born appropriate size for gestational age (AGA) and 25 SGA (14 in the <3rd percentile and 11 in the 3rd-10th percentile). RESULTS; The SGA 3rd-10th percentile children were already insulin resistant at prepubertal age (I(F) 39.6 +/- 16.8 vs. 27 +/- 12 pmol/l, P < 0.01, and HOMA-IR 1.4 +/- 0.6 vs. 0.95 +/- 0.42 in SGA vs. AGA children, P < 0.05). Their IGF-1 and IGFBP-3 concentrations were significantly lower than those in AGA children (160.4 +/- 66.2 vs. 207 +/- 66.8 microg/l, P < 0.05 and 2.3 +/- 0.4 vs. 3.51 +/- 1.21 mg/l in SGA vs. AGA children, P < 0.01). The SGA <3rd percentile children had higher adiponectin (15.6 +/- 5.7 mg/l, P < 0.05) and IGFBP-1 levels (113.5 +/- 33.9 microg/l, P < 0.05) than AGA children (11.3 +/- 6.6 mg/l and 90.8 +/- 24.2 microg/l, respectively) and lower IGF-1 and IGFBP-3 concentrations (162.6 +/- 68.4 microg/l, P < 0.05 and 2.4 +/- 0.7 mg/l, P < 0.01). They also had significantly lower waist circumference (P < 0.05). Leptin levels did not differ among groups, but an inverse correlation with IGFBP-1 (r = -0.55, P < 0.01) was found in the pooled SGA group. CONCLUSIONS: Intrauterine growth restriction appears to affect the IGF axis at prepubertal age, and its severity plays a role in insulin sensitivity.

Breastfeeding and vitamin D status in Greece during the first 6 months of life.

UNLABELLED: Since no foods are vitamin D supplemented in Greece, vitamin D status was assessed in mothers at birth and their infants up to the first 6 months of life, while they were exclusively breast-fed. This was a prospective study. Full-terms (n =35) born during the summer-autumn months and their mothers were assigned to the summer group and the remainder (n =31) to the winter group. One week after birth, serum 25-hydroxyvitamin D (25OHD) was significantly lower in the winter-born than in the summer-born neonates (6.7+/-0.7 vs. 10.1+/-0.9 ng/ml, P <0.01). The respective levels of parathyroid hormone (iPTH) were 64.9+/-13.4 and 33.9+/-4.4 pg/ml (P <0.01). The mothers had serum 25OHD levels of 10.8+/-1.0 ng/ml and iPTH levels of 15.2+/-3.5 pg/ml in the winter and 12.9+/-1.3 ng/ml and 24.8+/-4.8 pg/ml in the summer. During the 6-month follow-up, a steady increase in circulating 25OHD (up to 19.4+/-2.8 ng/ml, P <0.0001) and a decrease in iPTH (to 26.8+/-3.5 pg/ml, P =0.10) were observed in the infants born in the winter. In the summer-born infants, serum 25OHD did not change but iPTH had increased significantly by the 3rd month (59.4+/-21.8, P <0.05). Serum calcium (Ca) increased within normal limits during the study period in both groups. Serum phosphorus (Pi) started higher in the winter group (7.43+/-0.38 vs. 6.27+/-0.23 mg/dl, P <0.01) but thereafter, it was similar in both groups. Total alkaline phosphatase (ALP) increased in both groups during the study (164+/-15 vs. 219+/-17 IU/l, P <0.05 and 189+/-14 vs. 288+/-35 IU/l, P <0.001, respectively). Serum osteocalcin (OC) decreased in the winter-born neonates (32.0+/-3.4 vs. 21.5+/-3.4 ng/ml, P <0.05) and did not change in the summer group (28.9+/-3.5 vs. 26.5+/-2.8 ng/ml). CONCLUSION: Neonates who are breast-fed exclusively during the first 6 months of life are in need of vitamin D supplementation irrespective of the season even in a sunny country like Greece where foods are not supplemented.

Acute effects of gentamicin on urinary electrolyte excretion in neonates.

It has recently been shown that a single dose of gentamicin causes immediate and transient calcium and magnesium renal wasting in adults. The aim of this study was to determine the acute effect of gentamicin administration on renal electrolyte handling in preterm and full-term neonates. Twenty-three neonates treated with gentamicin for suspected infection were enrolled in the study. Serum and 3-h urine electrolytes were measured before and immediately after gentamicin infusion on the 1st, 3rd, 4th, and 7th day of treatment. Serum gentamicin levels were monitored. Gentamicin caused a statistically significant post-infusion increase in fractional excretion of sodium and magnesium and in the urine calcium to urine creatinine ratio. Potassium and phosphate fractional excretion remained unchanged. The disturbances in electrolyte excretion were observed in full-term as well as in preterm neonates. Serum electrolyte levels remained unchanged. In conclusion, therapeutic doses of gentamicin result in urinary loss of sodium, calcium, and magnesium in neonates immediately after the infusion of the drug. These electrolyte changes may be of clinical importance, especially for sick preterm neonates.

Renal function and effect of aminoglycoside therapy during the first ten days of life.

The effect of aminoglycoside administration on kidney functional maturation was evaluated in groups of 30 preterm and 30 fullterm infants who were treated for 7 days because of suspected infection. One of three different aminoglycosides was administered to each subgroup of ten preterm and ten fullterm infants. Changes in tubular function in groups of ten preterm and ten fullterm infants who were not given antibiotics were also compared. The mean gestational age for preterm infants from 32.5 to 33.6 weeks and for fullterm infants between 39.2 and 39.5 weeks. The renal tubular function was assessed by examining the fractional excretion of sodium (FENa), potassium (FEK), phosphorus (FEP), magnesium (FEMg) and uric acid (FEUA) as well as by the urinary excretion of calcium as the calcium/creatinine (UCa/UCr) ratio. Gentamicin affected the normal plasma creatinine (PCr) decline in both treated groups (fullterm and preterm). Disturbances in FENa and UCa/UCr were more pronounced in treated preterm than in fullterm infants especially after netilmicin and gentamicin administration. FEMg was significantly affected in preterm infants treated with gentamicin. The findings of this study indicate that the effect of aminoglycosides on tubular function is dependent upon kidney maturity and the type of the aminoglycoside used for therapy.