The Wound Healing Cascade
The Healing Cascade is a balancing act. In a normal wound, regulatory proteins, cells and an extracellular matrix (ECM) direct the orderly and timely process of wound healing. Chronic wounds are wounds that fail to progress in the healing cascade within 30 days. Chronic wounds are unbalanced, making it difficult to progress past the inflammatory phase to the proliferative phase of wound healing. Chronic wounds may need an advanced intervention to restore balance and facilitate the normalization of the healing process.
Normal Wounds
hemostasis
INFLAMMATION
- Secretion of immunomodulatory cytokines and chemokines
- Clearance of debris and bacteria
- Infiltration of inflammatory cells
PROLIFERATION
- Cellular migration
- ECM deposition
- New blood vessel formation
REMODELING
- Wound contraction
- Scare tissue formation
- Restoration of tensile strength
In a normal wound, there is an orderly and timely process of wound healing. The initial phase of wound healing is hemostasis. Within the first few days, a normal wound will move into the inflammation phase. During this phase immunomodulatory cytokines and chemokines are secreted, debris and bacteria are cleared, blood begins to flow, and fibroblasts are signaled. As the wound moves into the proliferation phase, granulation tissue forms, angiogenesis begins, cytokines decrease, fibroblasts increase, and epithelialization begins. The final phase is remodeling. During this phase the wound contracts, scar tissue is formed, and the tissue begins to strengthen.
Chronic Wounds
CHRONIC INFLAMMATION
- Persistent infection, biofilm
- Elevated inflammatory cytokines and chemokines
- Unresponsive cells
In a chronic wound, the wound can’t move past the inflammatory phase. Biofilm persists and there is an excess in pro-inflammatory proteins and MMPs compared to protease inhibitors. Growth factors are unresponsive or provide weak signals.
Chronic Wound Healing
post debridement
advanced intervention introduced to reblance the wound environment
Intervention, including debridement, should rebalance mediators and factors and move the wound past the inflammatory phase towards closure.