Plasma midkine concentrations in healthy children, children with increased and decreased adiposity, and children with short stature.

BackgroundMidkine (MDK), one of the heparin-binding growth factors, is highly expressed in multiple organs during embryogenesis. Plasma concentrations have been reported to be elevated in patients with a variety of malignancies, in adults with obesity, and in children with short stature, diabetes, and obesity. However, the concentrations in healthy children and their relationships to age, nutrition, and linear growth have not been well studied.Subjects and methodsPlasma MDK was measured by immunoassay in 222 healthy, normal-weight children (age 0-18 yrs, 101 boys), 206 healthy adults (age 18-91 yrs, 60 males), 61 children with BMI ≥ 95th percentile (age 4-18 yrs, 20 boys), 20 girls and young women with anorexia nervosa (age 14-23 yrs), and 75 children with idiopathic short stature (age 3-18 yrs, 42 boys). Body fat was evaluated by dual-energy X-ray absorptiometry (DXA) in a subset of subjects. The associations of MDK with age, sex, adiposity, race/ethnicity and stature were evaluated.ResultsIn healthy children, plasma MDK concentrations declined with age (r = -0.54, P ConclusionsIn healthy children, plasma MDK concentrations declined with age and were not significantly associated with sex, adiposity, or stature-for-age. These findings provide useful reference data for studies of plasma MDK in children with malignancies and other pathological conditions