Urinary levels of pyridinoline and deoxypyridinoline and bone mineral density in children with type 1 diabetes mellitus

Investigation of the relationship between serum sclerostin and dickkopf-1 protein levels with bone turnover in children and adolescents with type-1 diabetes mellitus

OBJECTIVES

Diabetes mellitus (DM) is widely known to have a detrimental effect on bone health and is associated with increased fracture risk. Recently, the Wnt/beta-catenin signaling pathway and its inhibitors sclerostin and dickkopf-1 (Dkk-1) were found to be involved in the control of bone mass. The present study aimed to measure serum sclerostin and Dkk-1 protein levels in children and adolescents with type-1 DM and compare with other bone turnover markers and bone mineral density (BMD).

METHODS

This study was performed on 40 children and adolescents with type-I DM and 40 healthy children and adolescents. Anthropometric measurements and pubertal examination were done. In addition to laboratory analysis, dickkopf-1, sclerostin, cross-linked N-telopeptides of type I collagen (NTx), bone alkaline phosphatase (bALP), and osteocalcin levels were studied. BMD of the participants was measured by calcaneus ultrasonography.

RESULTS

Dickkopf-1 levels of the children and adolescents with type-1 DM were significantly higher, vitamin D, NTx, osteocalcin, and phosphorus levels were significantly lower than those of the controls (p<0.001). Fasting blood glucose, HbA1c, and insulin were significantly higher in the type 1 DM group (p<0.01).

CONCLUSIONS

Both bone remodeling and its compensatory mechanism bone loss are lower in children and adolescents with type-1 DM than in the controls. Also, higher levels of Dkk-1 play a role in decreased bone turnover in these patients. Since Dkk-1 and sclerostin seem to take a role in treating metabolic bone diseases in the future, we believe that our findings are significant in this respective.

Relationship between bone turnover markers and oxidative stress in children with type 1 diabetes mellitus

BACKGROUND

Oxidative stress in children with type 1 DM (T1DM) may negatively affect the bone.

METHODS

This study included 40 children with T1DM as the patient group and 40 healthy children of matched age and sex as the control group. Plasma alkaline phosphatase, procollagen type-1 amino-terminal propeptide (P1NP), and urinary deoxypyridinoline (DPD) were measured to assess bone turnover. Glutathione, superoxide dismutase (SOD), and malondialdehyde (MDA) were measured to assess oxidative stress.

RESULTS

Patients with T1DM had a significantly lower P1NP level but a significantly higher urinary DPD level compared to the control group. Moreover, there were significantly lower glutathione and SOD levels with significantly higher MDA levels in patients with T1DM. We found a significant positive correlation between P1NP level and both glutathione and SOD levels but a significant negative correlation between P1NP and MDA in patients with T1DM. There was a significant negative correlation between DPD levels and both glutathione and SOD levels and a significant positive correlation between DPD and MDA. Moreover, glutathione was a significant predictor for both P1NP and DPD levels, while MDA was a significant predictor for P1NP levels.

CONCLUSIONS

There is an association between oxidative stress and bone turnover markers in children with T1DM.

IMPACT

Oxidative stress can negatively affect bone but the exact relationship between oxidative stress and bone turnover in T1DM has not been previously studied in pediatrics. For the best of our knowledge, our study was the first to assess the relationship between oxidative stress and bone turnover in children with T1DM. We revealed that increased oxidative stress in children and adolescents with T1DM may be involved in the impairment of bone turnover process, so treatment strategies toward better glycemic control and decreasing oxidative stress may be beneficial in preventing and treating diabetic bone disease in these children.

Impact of Type 1 Diabetes Mellitus on Skeletal Integrity and Strength in Adolescents as Assessed by HRpQCT

Adults with type 1 diabetes mellitus (T1DM) are at risk of premature osteoporosis and fractures. The onset of T1DM typically starts during childhood and adolescence. Thus, the effects of DM on the skeleton may be established during this period. Studies in children with T1DM primarily use DXA with conflicting results. We present the first study in adolescents assessing the impact of T1DM on skeletal microstructure and strength using HRpQCT. We recruited 22 patients aged 12 to 16 years with T1DM who were matched by age, gender, and pubertal stage with healthy controls. Paired t tests were applied to assess differences in cortical and trabecular microarchitecture measurements from HRpQCT, and skeletal strength from HRpQCT-derived microfinite element analysis. Subtotal body, lumbar, and pelvic parameters were assessed using DXA. There was no significant difference in subtotal body, lumbar spine, and pelvic BMD between T1DM and control pairs. However, tibial trabecular thickness was lower (-0.005 mm; 95% CI, -0.01 to -0.001; p = 0.029) and trabecular loading was lower at the distal radius (ratio of the load taken by the trabecular bone in relation to the total load at the distal end (Tb.F/TF) distal: -6.2; 95% CI, -12.4 to -0.03; p = 0.049), and distal and proximal tibia (Tb.F/TF distal: -5.2, 95% CI, -9.2 to -1.2; p = 0.013; and Tb.F/TF proximal: -5.0, 95% CI, -9.8 to -0.1; p = 0.047) in T1DM patients. A subanalysis of radial data of participants with duration of T1DM of at least 2 years and their matched controls demonstrated a reduced trabecular bone number (-0.15, 95% CI, -0.26 to -0.04; p = 0.012), increased trabecular separation (0.041 mm, 95% CI, 0.009-0.072; p = 0.015), an increased trabecular inhomogeneity (0.018, 95% CI, 0.003-0.034; p = 0.021). Regression models demonstrated a reduction in tibial stiffness (-0.877 kN/mm; p = 0.03) and tibial failure load (-0.044 kN; p = 0.03) with higher HbA1C. Thus, in adolescents with T1DM, detrimental changes are seen in tibial and radial microarchitecture and tibial and radial strength before changes in DXA occur and may result from poor diabetic control. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.