Preadipocyte factor-1 is associated with marrow adiposity and bone mineral density in women with anorexia nervosa.

CONTEXT

Despite having low visceral and sc fat depots, women with anorexia nervosa (AN) have elevated marrow fat mass, which is inversely associated with bone mineral density (BMD). Adipocytes and osteoblasts differentiate from a common progenitor cell, the human mesenchymal stem cell. Therefore, understanding factors that regulate this differentiation process may provide insight into bone loss in AN.

OBJECTIVE

The objective of the study was to investigate the relationship between preadipocyte factor-1 (Pref-1), a member of the epidermal growth factor-like family of proteins and regulator of adipocyte and osteoblast differentiation, and fat depots and BMD in AN.

DESIGN

This was a cross-sectional study.

SETTING

The study was conducted at a clinical research center.

PATIENTS

Patients included 20 women with AN (26.8 +/- 1.5 yr) and 10 normal-weight controls (29.2 +/- 1.7 yr).

INTERVENTIONS

There were no interventions.

MAIN OUTCOMES MEASURE

Pref-1, leptin, IGF-I, IGF binding protein (IGF-BP)-2 and estradiol levels were measured. BMD of the spine and hip was measured by dual-energy x-ray absorptiometry. Marrow fat content of the L4 vertebra and femur was measured by (1)H-magnetic resonance spectroscopy.

RESULTS

Pref-1 levels were significantly higher in AN compared with controls (P = 0.01). There was a positive correlation between Pref-1 and marrow fat of the proximal femoral metaphysis (R = 0.50, P = 0.01) and an inverse association between leptin and L4 marrow fat (R = -0.45, P < 0.05). There was an inverse association between Pref-1 and BMD of both the anteroposterior spine and lateral spine (R = -0.54, P = 0.003; R = -0.44, P = 0.02, respectively).

CONCLUSIONS

Pref-1 is elevated in AN. Pref-1, IGF-I, IGF-BP2 and leptin are associated with marrow adiposity and BMD.