A Galler, V Schuster, and W Kiess
J Kratzsch, A Deimel, A Galler, T Kapellen, A Klinghammer, and W Kiess
OBJECTIVE: We investigated whether or not serum levels of the soluble leptin receptor (sOB-R) and leptin are related to anthropometric and metabolic changes during pubertal development of children and adolescents with type 1 diabetes mellitus. DESIGN AND METHODS: Blood levels of sOB-R, leptin and HbA1C, as well as body-mass index (BMI), diabetes duration and daily insulin doses, were determined in 212 (97 girls; 115 boys) children with type 1 diabetes mellitus and compared with the sOB-R serum levels in 526 healthy children and adolescents. RESULTS: OB-R serum levels and parallel values of the molar ratio between sOB-R and leptin were significantly higher in children with diabetes than in normal children (P<0.05) in almost all investigated Tanner stages. Furthermore, in the entire group of patients, we demonstrated statistically significant correlations (P<0.02) between sOB-R and the duration of diabetes (r=0.30), HbA1c levels (r=0.32) and the insulin dose (r=0.18). Multiple-regression analysis revealed that HbA1c (12.4%), height (7.9%) and duration of diabetes (8.7%) contributed to 29% variance of sOB-R in diabetic children. CONCLUSIONS: Our data suggest that poor glycemic control in diabetes may lead to increased serum levels of sOB-R. This regulation of sOB-R appears to be independent of leptin, but may have an impact on leptin action. The consequently developing molar excess of sOB-R related to leptin could reduce leptin sensitivity and may, therefore, influence leptin-related anthropometric and metabolic abnormalities.
J Kratzsch, I Knerr, A Galler, T Kapellen, K Raile, A Körner, J Thiery, J Dötsch, and W Kiess
Objective: Type 1 diabetes mellitus (T1DM) leads to increased serum levels of the soluble leptin receptor (sOB-R) by an as yet unknown cellular mechanism. The aim of our study was to investigate potential metabolic factors that may be associated with the induction of the sOB-R release from its membrane receptor.
Materials and methods: Twenty-five children (aged between 1.5 and 17.0 years) were studied at the onset of T1DM. Blood samples were collected before (n = 25), during the first 18 h (mean ± S.D. 11.1 ± 4.3 h, n = 16) and 92 h (47.5 ± 22.5 h; n = 14) after beginning insulin therapy. Serum sOB-R and leptin levels were determined by in-house immunoassays.
Results: The sOBR-level and the molar sOB-R/leptin ratio were significantly higher before than after starting insulin treatment (P < 0.05). In contrast, leptin levels were significantly lower (P < 0.05) before insulin therapy. The correlation between sOB-R and blood glucose (r = 0.49; P < 0.05), as well as sOB-R with parameters of ketoacidosis, such as pH (r = −0.72), base excess (r = −0.70), and bicarbonate (r = −0.69) (P < 0.0001) at diagnosis of T1DM remained significant during the first 18 h of insulin treatment. Multiple regression analysis revealed that base excess predicted 41.0% (P < 0.001), age 16.4% (P < 0.05), and height SDS 13.9% (P < 0.01) of the sOB-R variance.
Conclusions: Metabolic decompensation in children with new onset T1DM is associated with dramatic changes of the leptin axis; serum levels of sOB-R are elevated and of leptin are reduced. The molar excess of sOB-R over leptin (median 11.3) in this condition may contribute to leptin insensitivity. Upregulation of the soluble leptin receptor appears to be a basic mechanism to compensate for intracellular substrate deficiency and energy-deprivation state.