Regulatory T cells modulate postischemic neovascularization.

Area of Science:

• Immunology
• Vascular Biology
• Regenerative Medicine

Background:

• T lymphocytes, including CD4+ and CD8+ T cells, are crucial for post-ischemic neovascularization.
• Costimulatory pathways like B7/CD28 and CD40-CD40 ligand, along with regulatory T cells (Treg cells), influence T-cell activation and immune responses.
• CD28 signaling is vital for Treg cell generation and homeostasis, suggesting a role for Treg cells in immune suppression and T-cell balance.

Purpose of the Study:

• To investigate the hypothesis that Treg cell activation modulates the immunoinflammatory response to ischemic injury.
• To determine the effect of Treg cell modulation on post-ischemic neovascularization and blood vessel growth.

Main Methods:

• Induction of ischemia via femoral artery ligation in mice deficient in CD28, B7-1/2, or CD40.
• Assessment of post-ischemic inflammatory response, vessel growth, foot perfusion, and capillary density.
• Experimental Treg cell deletion using anti-CD25 treatment and adoptive transfer experiments in Rag1(-/-) mice.

Main Results:

• CD40 deficiency reduced inflammation and vessel growth; CD28 deficiency, characterized by fewer Treg cells, significantly enhanced neovascularization.
• Disruption of B7-1/2 signaling or Treg cell depletion markedly improved post-ischemic neovascularization.
• Conversely, enhancing Treg cell numbers in CD28-deficient mice reduced inflammation and neovascularization, confirming Treg cells' inhibitory role.

Conclusions:

• Regulatory T (Treg) cell activity plays a significant role in modulating the process of post-ischemic neovascularization.
• Targeting Treg cells represents a potential therapeutic strategy to enhance blood vessel repair following ischemic events.