Substance P blocks ovariectomy-induced bone loss by modulating inflammation and potentiating stem cell function.

Area of Science:

• Bone Biology and Disease
• Immunology
• Regenerative Medicine

Background:

• Osteoporosis is an age-related bone disease characterized by excessive bone resorption and chronic inflammation.
• T helper 17 (Th17) cells, via IL-17 secretion, are key drivers of bone loss in osteoporosis.
• Substance P (SP) exhibits anti-inflammatory properties and promotes stem cell niche restoration.

Purpose of the Study:

• To investigate the therapeutic potential of systemically administered Substance P (SP) in ovariectomy (OVX)-induced osteoporosis.
• To evaluate SP's effects on bone microarchitecture, mineral density, inflammation, and stem cell function in an osteoporosis model.

Main Methods:

• Ovariectomy (OVX) was performed to induce osteoporosis in a preclinical model.
• Systemic injection of Substance P (SP) was administered to OVX-induced osteoporotic subjects.
• Analyses included bone microarchitecture, mineral density, immune cell profiling (Treg, Th17), and bone marrow stem cell (BMSC) function.

Main Results:

• SP treatment significantly prevented OVX-induced bone loss, preserving bone microarchitecture and mineral density.
• SP ameliorated chronic inflammation by promoting regulatory T (Treg) cell polarization and inhibiting osteoclastogenic Th17 cell development.
• SP rejuvenated bone marrow stem cells (BMSCs), enhancing their repopulation and osteogenic differentiation capacity.

Conclusions:

• Systemic Substance P (SP) administration is a promising therapeutic strategy for blocking osteoporosis progression.
• SP demonstrates efficacy in treating chronic inflammatory diseases associated with stem cell dysfunction.
• SP's dual action on immune modulation and stem cell regeneration highlights its broad therapeutic potential.