Serum sphingolipids and inflammatory mediators in adolescents at risk for metabolic syndrome.

The purpose of this study was to determine low-grade inflammation associated with obesity that is mediated partially by TNF-α, an adipocytokine which stimulates sphingomyelinase activity in adipocytes. Circulating ceramide (Cer) and sphingosine 1-phosphate (S1P) are elevated in genetically obese (ob/ob) mice. We aimed to determine whether serum sphingolipid concentrations correlate with measures of obesity, insulin resistance, and lipid profiles in overweight versus lean adolescents. This cross-sectional study recruited 30 healthy overweight (body mass index, BMI ≥ 85%) and 15 lean (BMI 10-84%) adolescents. Anthropometric measurements and fasting blood samples were collected at one clinic visit. Serum glucose, insulin, and fasting lipid profiles were measured. Serum adipocytokine concentrations were measured by ELISA or colorimetric assay and sphingolipids were measured by HPLC-mass spectrometry. Between group differences in serum sphingolipid concentrations were assessed. Correlations between sphingolipid concentrations and (i) body mass index, (ii) calculated homeostasis model assessment of insulin resistance (HOMA-IR), (iii) adipocytokines, and (iv) lipoproteins were determined. The results showed that significant differences in HOMA-IR (4.5 ± 3.2 vs. 1.2 ± 0.7), free fatty acids (0.8 ± 0.3 mmol/l vs. 0.4 ± 0.3 mmol/l), and adiponectin (6.4 ± 3.8 vs. 12.6 ± 9.9 µg/ml) were seen between groups (overweight vs. lean). There were significant correlations between Cer and TNF-α (r = 0.429), S1P and TNF-α (r = 0.288), Cer and adiponectin (r = 0.321), Cer:S1P and adiponectin (r = 0.324), Cer and HOMA-IR (r = 0.307), and Cer:S1P and LDL cholesterol (r = 0.453); these associations persisted after adjustment for BMI Z-score, sex, and Tanner stage. We concluded that elevated sphingolipid concentrations correlate with TNF-α, adiponectin, lipoprotein profiles, and HOMA-IR. Ceramide is associated with atherogenic lipid profiles and the development of insulin resistance in obese adolescents, similar to adults.

The effect of iron therapy on the growth of iron-replete and iron-deplete children.

This prospective, double-blind, placebo-controlled trial was designed to study the effect of iron therapy on the growth of iron-replete and iron-deficient children, and to study the change in iron status in iron-deficient children with iron therapy. One hundred and fifty children (aged 6-24 months) were included in the study. After an informed written consent, 100 healthy children, who were iron replete (group I) according to preset criteria, were randomly allocated to receive iron supplements 2 ng/kg/day (group IA) or placebo (group IB). Fifty iron-deficient children (group II) were administered iron syrup 6 mg/kg/day. Growth parameters (weight, length and head-circumference) and hematological parameters were studied for 4 months. Iron therapy, as compared with placebo, produced a significant improvement of mean monthly weight gain (p < 0.001) and linear growth (p < 0.001) in the iron-deficient children. However, it significantly decreased the weight gain (p < 0.001) and linear growth (p < 0.001) of iron-replete children. Caution should therefore be exercised while supplementing iron to children with apparently normal growth and when the iron status of the child is not known.

Current trends in microbial steroid biotransformation.

Microbial transformations of various steroids are reviewed. Developmental studies on immobilization of microbial cells, techniques for selective transformation and better yields of desired metabolites are highlighted. The present position of microbial biotechnology in the steroid drug industry and the future prospects are discussed. Various steroid substrates, their metabolites and the micro-organisms used for the transformations are compiled covering the literature for the period late 1987-mid 1992.