Substance P-Mediated Vascular Protection Ameliorates Bone Loss

Area of Science:

• Endocrinology and Bone Biology
• Vascular Biology and Angiogenesis
• Neuropeptide Signaling

Background:

• Estrogen deficiency, induced by ovariectomy (OVX), leads to bone loss through pathological cellular events.
• Type H vasculature is crucial for bone healing, and its density is reduced in OVX-induced estrogen deficiency.
• Oxidative stress and endothelial dysfunction are early consequences of estrogen deficiency, impairing vascular function and promoting bone loss.

Purpose of the Study:

• To investigate the preventive effects of systemically administered Substance P (SP) on OVX-induced vascular loss and osteoporosis.
• To determine if SP can counteract the negative effects of estrogen deficiency on bone vasculature and density.

Main Methods:

• Ovariectomy (OVX) was performed on rats to induce estrogen deficiency.
• Substance P (SP) was administered systemically to OVX rats twice weekly for 4 weeks post-OVX.
• Evaluated changes in antioxidant enzyme activity, type H vessel density, nitric oxide levels, angiogenic factors, and bone density.

Main Results:

• OVX rats exhibited decreased antioxidant activity, reduced type H vessels, and lower angiogenic factors in bone marrow, leading to inflammation and bone loss.
• SP pretreatment prevented the loss of type H vessels in OVX rats.
• SP administration increased nitric oxide levels and sustained angiogenic factors, effectively inhibiting bone density reduction.

Conclusions:

• Early systemic administration of Substance P (SP) can prevent osteoporosis development following estrogen deficiency.
• SP protects bone vasculature by modulating oxidative stress and maintaining angiogenic potential during the early stages of estrogen deficiency.
• SP represents a potential therapeutic strategy for mitigating bone loss associated with estrogen deficiency.