Increased levels of Dickkopf-1 are indicative of Wnt/β-catenin downregulation and lower osteoblast signaling in children and adolescents with type 1 diabetes mellitus, contributing to lower bone mineral density

Higher levels of Dickkopf-1, which is an inhibitor of Wnt/beta-catenin bone metabolic pathway, could be indicative of downregulated Wnt system, with possible lower osteoblast activation and higher osteoclast signaling in type 1 diabetes mellitus children and adolescents. Dickkopf-1 could significantly contribute to diabetes osteopathy. Increased fracture risk and elevated Dickkopf-1 levels, which is an inhibitor of Wnt/beta-catenin bone metabolic pathway, have been documented in adult patients with type 2 diabetes mellitus (T2D), while no relevant data exist on childhood type 1 diabetes (T1D). Our aim was to study plasma Dickkopf-1 distribution in children and adolescents with T1D and to correlate Dickkopf-1 with metabolic bone markers and bone mineral density (BMD). We evaluated 40 children and adolescents with T1D (mean +/- SD age 13.04 +/- 3.53 years, T1D duration 5.15 +/- 3.33 years) and 40 healthy age-matched and gender-matched controls (age 12.99 +/- 3.3 years). Dickkopf-1 and bone metabolic markers were measured, while total body and lumbar spine BMD were evaluated with dual-energy X-ray absorptiometry (DXA). Dickkopf-1 demonstrated a Gaussian distribution, with higher levels in T1D patients (13.56 +/- 5.34 vs 11.35 +/- 3.76 pmol/L, p = 0.024). Higher values were found in boys and in prepubertal children. Dickkopf-1 correlated positively with osteoprotegerin and fasting glucose in patients, while positive correlation with sclerostin and total soluble receptor activator of nuclear factor-kappaB ligand (s-RANKL) was found in controls. Positive correlations with C-telopeptide cross-links (CTX), osteocalcin, alkaline phosphatase, phosphate, and insulin-like growth factor 1 (IGF1) were documented in both groups. Lumbar spine Z-score was positively associated with Dickkopf-1 in controls, while a negative trend was found in patients. Higher levels of Dickkopf-1 could indicate a downregulated Wnt/beta-catenin system with possible lower osteoblast activation and higher osteoclast signaling in T1D children and adolescents. Dickkopf-1 could possibly be a significant contributor of T1D osteopathy. Future therapies could focus on Wnt/beta-catenin metabolic pathway.