Compensatory lymphangiogenesis is required for edema resolution in zebrafish

Area of Science:

• Vascular Biology
• Regenerative Medicine
• Fluid Homeostasis

Background:

• Edema, or interstitial fluid accumulation, complicates healing.
• Lymphangiogenesis is vital for edema clearance, but its dynamics during tissue repair are poorly understood.
• Observing lymphangiogenesis in real-time during tissue repair in animal models is challenging.

Purpose of the Study:

• To investigate the dynamic changes in lymphangiogenesis during edema resolution.
• To explore the mechanisms of compensatory lymphatic activation.
• To establish a novel in vivo model for studying lymphangiogenesis during tissue repair.

Main Methods:

• Zebrafish larvae were subjected to osmotic stress to induce edema.
• Intravital imaging of vascular transgenic larvae was used to observe lymphatic vessel remodeling.
• Translating ribosome affinity purification (TRAP) analyzed the translatome of lymphatic and venous endothelial cells in vivo.

Main Results:

• Significant lymphatic vessel remodeling and increased lymphatic endothelial progenitor cells were observed during edema recovery.
• Active lymphangiogenesis, characterized by sustained expansion and remodeling of primary lymphatics, occurred during the recovery phase.
• Upregulation of pro-lymphangiogenic genes, including vegfr2 and vegfr3, was identified in lymphatic endothelial cells.

Conclusions:

• Compensatory lymphangiogenesis plays a critical role in edema fluid clearance and tissue recovery.
• Inhibition of lymphangiogenesis impaired edema resolution.
• The study provides a new model for in vivo imaging of lymphangiogenesis and a novel approach to investigate lymphatic activation.