Does Aging Activate T-cells to Reduce Bone Mass and Quality?

Area of Science:

• Gerontology
• Immunology
• Bone Biology

Background:

• Bone mass and quality decline with age, increasing osteoporosis risk.
• Osteoporosis affects a third of men over 50 and half of postmenopausal women.
• Genetics and environmental factors influence age-related bone loss.

Purpose of the Study:

• Review recent studies on the etiology of age-dependent bone mass decline.
• Propose a mechanism integrating genetic and environmental factors in bone loss.
• Explore the role of immune system dysregulation in osteoporosis.

Main Methods:

• Review of recent scientific literature.
• Synthesis of data from animal models and human studies.
• Proposal of a novel mechanism involving T-cells and inflammation.

Main Results:

• Aging and menopause dysregulate the immune system, causing sterile low-grade inflammation (inflammaging).
• Inflammation mediates bone loss in both sexes.
• Senolytics improved bone mass in aged mice, suggesting potential therapeutic targets.

Conclusions:

• Aging activates senescent, proinflammatory T-cells, contributing to bone loss.
• Targeting senescent T-cells is a promising strategy for osteoporosis therapy.
• Inflammaging is a key mechanism in age- and estrogen-loss-dependent osteoporosis.