High glucose concentrations alter the biomineralization process in human osteoblastic cells

Area of Science:

• Endocrinology
• Bone Biology
• Cell Biology

Background:

• Diabetes mellitus (DM) is linked to bone complications like osteopenia and osteoporosis.
• Chronic inflammation, often associated with DM, contributes to bone resorption and insulin resistance.
• The precise mechanisms of bone complications in DM remain unclear, with conflicting data on glucose effects on osteoblasts.

Purpose of the Study:

• To investigate the impact of high glucose concentrations on biomineralization and inflammation markers in a human osteoblastic cell line.
• To elucidate the effects of hyperglycemia on osteoblast function and inflammatory pathways relevant to bone health.

Main Methods:

• Human osteoblastic cells were exposed to physiological (5.5 mM) and high glucose concentrations (up to 24 mM).
• Evaluated biomineralization quantity and quality (calcium deposits).
• Assessed mRNA expression of bone-related proteins (osteocalcin, bone sialoprotein, Runx2), RANKL/OPG, cytokines (IL1, IL6, IL8, IL10, MCP-1, TNF alpha), and toll-like receptors (TLR-2, -3, -4, -9).

Main Results:

• High glucose (12 mM and 24 mM) altered biomineralization, increasing mineralization quantity but diminishing quality.
• Elevated glucose led to increased RANKL and decreased OPG mRNA expression.
• Increased expression of osteocalcin, bone sialoprotein, Runx2, and inflammatory cytokines (IL1beta, IL6, IL8, MCP-1, IL10) was observed.
• High glucose and osmotic stress induced overexpression of TLR-2, -3, -4, and -9 in osteoblastic cells.

Conclusions:

• Hyperglycemia in diabetes mellitus adversely affects osteoblast biomineralization and promotes a pro-resorptive bone environment.
• Increased inflammatory cytokine expression and TLR activation suggest a role for inflammation and osmotic stress in diabetes-related bone pathology.
• These findings highlight potential mechanisms linking diabetes to bone loss and periodontal disease.