Close negative correlation of local and circulating Dickkopf-1 and Sclerostin levels during human fracture healing

Area of Science:

• Orthopedics
• Endocrinology
• Regenerative Medicine

Background:

• Wnt signaling is crucial for fracture healing, but human data is limited.
• Existing research primarily uses rodent models, necessitating human-specific investigations.
• Dickkopf-1 (DKK1) and sclerostin (SOST) are key regulators of Wnt signaling.

Purpose of the Study:

• To investigate local and circulating levels of DKK1 and SOST in patients undergoing fracture healing.
• To explore the association between DKK1 and SOST during the healing process.
• To identify factors influencing DKK1 and SOST levels and their relation to fracture non-union.

Main Methods:

• Enzyme-linked immunosorbent assay (ELISA) was used to measure DKK1 and SOST concentrations.
• Measurements were taken at the fracture site and in circulation in 69 patients.
• Patient-related factors like age, smoking, diabetes, and sex were recorded.

Main Results:

• DKK1 and SOST exhibited a significant inverse correlation throughout fracture healing.
• DKK1 levels decreased, while SOST levels increased immediately post-trauma.
• Postoperatively, DKK1 peaked at week 2 and SOST at week 8.
• Age and smoking affected DKK1/SOST balance; diabetes and sex did not.
• Elevated SOST without DKK1 decrease correlated with non-union in younger patients (<50 years).

Conclusions:

• DKK1 and SOST show rapid, inverse dynamics locally and systemically, highlighting their critical role in human fracture healing.
• Immediate compensatory feedback mechanisms between DKK1 and SOST are evident.
• Dual blockade of DKK1 and SOST may enhance Wnt-targeted therapies for fracture healing.