Healing and Tissue Repair: Growth Factors and Cytokines

Tissue repair is a complex biological process involving various cellular and molecular mechanisms that restore tissue integrity after injury.

Role of Growth Factors

Growth factors are signaling molecules essential for cellular proliferation and differentiation during tissue repair. Key examples include:

• Platelet-Derived Growth Factor (PDGF) – Stimulates fibroblast growth and collagen production.
• Epidermal Growth Factor (EGF) – Promotes epithelial cell migration and mitosis.
• Transforming Growth Factor-Beta (TGF-β) – Modulates inflammation and fibrosis.

Cytokines and Their Functions

Cytokines mediate inflammation and immune responses critical for tissue repair. Some important cytokines include:

• Interleukin-1 (IL-1) – Initiates inflammation and recruits immune cells.
• Tumor Necrosis Factor-Alpha (TNF-α) – Regulates apoptotic pathways and immune responses.
• Interferons (IFNs) – Assist in cellular antiviral defense and immune regulation.

Phases of Tissue Repair

The healing process occurs in three distinct phases:

1. Inflammatory Phase – Involves clot formation and immune cell activation.
2. Proliferative Phase – Fibroblast proliferation, angiogenesis, and extracellular matrix deposition.
3. Remodeling Phase – Collagen organization and wound contraction.

Conclusion

Understanding the role of growth factors and cytokines in tissue repair enhances therapeutic strategies for improved healing outcomes.