Context: Leptin might be more important as a starvation hormone than as a satiety signal. The role of the soluble leptin receptor (sOB-R) and its regulation in children with protein-energy-malnutrition (PEM) is poorly understood.

Design: We elucidated the effect of intensive nutritional support on the leptin axis in 26 severely malnourished toddlers who received infant milk based formula for two weeks via continuous enteral tube feeding followed by two weeks "ad libitum" feeding. Serum levels of leptin, sOB-R, IGF-I, and IGF-binding protein 3 (IGFBP-3) as well as anthropometric measurements were determined at the beginning of the study and at 2 week intervals. The control group consisted of 13 well-nourished children.

Results: The following were changes in the PEM toddlers after the nutritional support: Leptin increased significantly (P < 0.001) reaching 166% of levels observed in control group. sOB-R decreased significantly (P < 0.001), and a 142-fold molar excess of sOB-R over leptin was found. There were significant correlations between leptin and IGF-I after 2 weeks and IGFBP-3 during the whole study. sOB-R was not correlated with any anthropometric data, whereas IGF-I was a predictor of sOB-R variance in the PEM toddlers (19.9%, P = 0.022).

Conclusion: It can be concluded, that sOB-R was a modulatory effect on leptin in PEM children during nutritional recovery and participates in their adaptive survival mechanisms. Leptin and the molar excess of sOB-R over leptin are better biomarkers of nutritional status than IGF-I in PEM children during nutritional recovery.