ESPE Abstracts

Background: Fibroblast growth factor 21 (FGF21) is a metabolic and growth regulator. The growth-promoting effect of GH in children with GH deficiency (GHD) depends on many factors. FGF21 concentration in and its interaction with growth deficiency and growth response to GH therapy in GHD was not examined.

Objective and hypotheses: To estimate the FGF21 concentration and its correlation with degree of growth deficiency and growth response in non-obese, prepubertal children with isolated GHD before (GHD before GH) and after 6 months of GH therapy (GHD after 6 m GH).

Method: The 32 (22 boys, 10 girls) children with GHD (mean height 117.9 cm, −2.77 S.D., mean BMI −0.75 S.D.), mean age 8.87 years. Control group (CG): 18 (11 boys, 9 girls) age matched healthy children (mean height 125.8 cm, −0.93 S.D., mean BMI −0.28 S.D.). Serum fasting FGF21 was measured in all and in GHD after 6 months (m). In GHD IGF1 was measured before and after 3 months (m) of GH therapy. GHD patients were divided into subgroups dependently on degree of growth deficiency before GH therapy: A < median height S.D. and B > median height S.D..

Results: The median concentration of FGF21 did not differ significantly between CG, GHD before GH and GHD after 6 m, however in CG it was lower than in GHD (94.1 vs 99.8 before GH and 133 pg/ml after 6 m GH). IGF1 was significantly higher after 3 m of GH than before GH (242 vs 116.4 ng/ml). FGF21 after 6 m correlated with height S.D. after 6 m: the higher FGF21 after 6 m the more profound growth deficiency (r=−0.50, P<0.05). Stepwise discriminant analysis showed that FGF21 and IGF1 are differentiating features between A and B subgroup (canonical factor: 0.49). In subgroup A FGF21 was higher than in subgroup B. FGF21 before GH was higher in subgroup A than in subgroup B with border significance (median 111 vs 84.5 pg/ml, P=0.07) while FGF21 in subgroup A after 6 m of GH was significantly higher (median 174.5 vs 94.1 pg/ml, P<0,05). IGF1 was significantly lower in group A than in B both before and after 3 months of GH therapy.

Conclusion: FGF21 has potential negative impact on stature growth in GHD children.