Wound Bed Preparation: Correction of Cellular Dysfunction

Without a healthy wound bed, most wound care products are ineffective. In order to create a healthy wound bed, there are five steps required. The first three steps in wound bed preparation are the restoration of the bacterial balance, the elimination of nonviable tissue, and providing a moist environment/maintaining moisture balance.

 

The fourth step is what we are going to focus on right now–the correction of cellular dysfunction. (The final step is the restoration of biochemical balance, which we will discuss in the final post in this series.)

 

Cells play a key role in wound healing

Cells play a key role in angiogenesis (new blood vessel formation), as well as adhesion, migration, proliferation, and capillary bed formation. Keratinocytes are key cells involved in restoring the epidermal skin layer. In chronic wounds, these keratinocytes don’t lose their nuclei, thus they are incapable of normal cellular migration over the wound bed. (On the flip side, sometimes hyperproliferation of keratinocytes occurs, which is when the cells reproduce rampantly, resulting in a thick layer of cells at the wound margin.)

 

What happens to the wound environment in chronic wounds?

 

In chronic wounds, the environment is typically proinflammatory and full of high levels of cytokines and matrix metalloproteinases. In addition, this proinflammatory environment is lacking the tissue inhibitors of metalloproteinases. This out-of-balance state impairs the normal progression of wound healing and closure.

 

Chronic wounds are slow to heal, thanks to cells that become senescent (think lazy, old, unresponsive, unable to divide). When cells are senescent, they are also unresponsive to cytokines (protein messengers) and growth factors. Because these cells are unresponsive, chronic wounds are often inflamed, slow to close, and secrete excessive wound fluid, all of which in turn results in cellular senescence. When wound edge migration is slow or nonexistent, it stops the normal programmed cellular death within fibroblasts and keratinocytes. In other words, it’s a vicious cycle.

 

Systemic factors often exacerbate chronic wounds

Often, chronic wounds are exacerbated by underlying patient physiological issues, including diabetes, vascular insufficiency, ischemia, and nutritional deficiencies. When cells are unresponsive, the use of topical growth factors is often unsuccessful, as the underlying cellular dysfunction is what needs to be addressed.

 

The extracellular matrix plays a role in wound healing

The extracellular matrix (ECM), a structure that surrounds and supports cells, contains specialized proteins and molecular signals that are used to control the cell’s shape, migration, proliferation, differentiation, and overall survival.

 

Collagen is a component of the ECM, because it’s an important connective protein and structural component within cells. Collagen helps with clotting factors, promoting granulation and epithelialization, and forming a stronger tissue base for remodeling. Collagen is also a key component in products used for wound healing, as it assists in cell differentiation, cell behavior, cell migration, proliferation, and synthesis of a number of proteins, including collagen itself.

 

Wound dressings can promote healing in chronic wounds

Recent research has indicated the use of collagen can stimulate proliferation, migration, and the synthesis of new proteins in a chronic wound, and that adding collagen (or specifically configured denatured collagen) to wound dressings can target the nonadvancing wound edge and help promote wound closure.

 

Such a dressing should absorb exudate, be non-adherent to the wound bed, act as a depot for cells and proteins that help in wound closure, and contain topical antibacterial agents to maintain bacterial balance. To learn more about advanced wound products that can assist in wound bed preperation, consider taking one of the courses offered by WoundEducators.com

 

Register today and begin an exciting career as a certified wound specialist.

 

Sources

Elizabeth A. Ayello, PhD, RN, ACNS-BC, ETN, FAPWCA, FAAN (2009). The TIME Principles of Wound Bed Preparation. Retrieved April 15 from www.woundcarejournal.com.

 

Frank DiCosmo, PhD (2009). Edge Effect: The Role of Collagen in Wound Healing. Retrieved April 17 from www.woundcarejournal.com.

 

Chuck Gokoo, MD, CMO CWS, FACCWSa (2009). A Primer on Wound Bed Preparation. Journal of the American College of Certified Wound Specialists. 1, 35–39.

 

Kathryn Vowden RGN, DPSN(TV) & Peter Vowden MD, FRCS (2002). Wound Bed Preparation. Retrieved April 14 from www.worldwidewounds.com.