Role of Collagen

What is Collagen?

Collagen is the most prevalent protein in the human body and provides strength and structure to the tissues. There are at least 29 distinct types of collagen, each with its own unique molecular form and type specific purposes. Collagen, in its proper molecular form specific to skin tissue with self-assembling capabilities, has benefited the human skin tissue healing. Collagen type I, III, and V are the most important for wound healing.

Collagen at molecular level:

·         Collagen fiber bundles are arranged specific to tissue function in the skin, where they provide support. These fibers are in turn made of smaller units called fibrils.                   

·         The collagen fibrils are made of a repeating pattern of collagen molecules. Gaps and overlapping region between the molecules are specific, where overlapping of molecules takes place in the gaps as shown below:

·         Molecules consist of three helical amino acid chains with a characteristic Gly-X-Y repeat unit

·         These helical chains intertwine to form a super helix 

·         Molecules have non-helical ends

·         The non-helical regions form cross-links with other collagen molecules

What is the role of collagen in wound healing?

The living body is like a complicated computer software program. Whenever there is injury to the skin tissue, the body is programmed to respond to such a wound with a series of complex sequential cellular and vascular activities. The sequential wound healing activity stages are:

1.                Hemostasis (Blood Clotting):           

Platelets aggregate within a few minutes post-injury at the injury site to form a fibrin clot which helps to control bleeding. This phase is called hemostasis. Collagen is an integral part of the clotting mechanism. It participates in platelet activation, factor intrinsic and extrinsic clotting cascade, and is also a cofactor for thrombosis.

2.                 The Reactive or Inflammatory Stage: 

This is also known as “The Stuck Stage”.  In this stage, bacteria and debris are removed and factors are released that cause the migration and division of cells involved in the proliferative or regenerative phase. Moreover, MMP’s are released, which are a part of the inflammatory cells that give rise to elevated levels of proteases or degrading proteins. These MMPs then help in degrading the extra-cellular matrix components, growth factors, and receptors that are essential for healing.

3.                 Regeneration:

This phase leads to the formation of a tissue template. It promotes replication, adhesion, and maturation of fibroblasts. In this phase, the tissue regains structural integrity and develops binding sites for epithelial cells. This is where collagen plays an important role in bridging with the epithelial cells and cellular proliferation atop the wound bed, thereby leading to granular tissue formation.

4.                 Re-modeling stage:

During this stage, collagen is realigned and remodeled along the tension lines to increase the tensile strength of the tissue. In this phase, collagen plays an important role in structural organization, acceleration of the reconstruction of tissues, and reduction in contracture and scarring. The tissue is hence able to regain its original integrity.

Throughout these phases of healing, collagen performs the following functions in wound healing:

·         Guiding Function:

 Collagen fibers serve to guide fibroblasts. Fibroblasts migrate along a connective tissue matrix. 

·         Chemotactic Properties:

 The large surface area available on collagen fibers can attract fibrogenic cells which help in healing.

·         Nucleation:

Collagen, in the presence of certain neutral salt molecules, can act as a nucleating agent causing formation of fibrillar structures. A collagen wound dressing

 might serve as a guide for orienting new collagen deposition and capillary growth.

·         Hemostatic properties:

Blood platelets interact with the collagen to make a hemostatic plug. For healing to occur the body must deliver an adequate amount of the proper resources to sustain the complex sequence of cellular activity present in the wound bed.

Whenever adequate resources are not being delivered to the wound bed, or there is wound bed interference with cellular activity, the complex sequential wound healing process can be severely hindered or the wound will refuse to close.  Some of the major causes of wound bed interference with cellular activity are:

• Improper moisture content.

• Inadequate delivery of oxygen (pH needs to be in the range 5.5-6)

• Infection (needs to be less than 100,000 organisms per gram of tissue).

• Other factors hindering wound healing are genetic or immune disorders, vascular insufficiency, infection, or nutrition.          

Caregivers should consider hindering factors when assessing their patients, just as they would document medications or products that may interfere with the body’s natural cellular activity or trigger an autoimmune reaction. With such factors involved infections and complications can arise in the body at any time and a wound bed is at risk if left exposed.  Unclosed wounds can critically compromise a diabetic patient’s health because the area can become a conduit for septicemia (blood poisoning). 

Collagen is one of the body’s key natural resources and a component of skin tissue that can benefit all stages of the wound healing process.  When collagen is made available to the wound bed, closure can occur. Wound deterioration, followed sometimes by procedures such as amputation, can thus be avoided.

 What makes Type I collagen so essential?

It is necessary for every phase of wound healing. It acts as a conductor, directing the entrances and exits of each performer in the wound healing process. Without collagen, wounds will not heal. If the body has difficulty supplying its own collagen to the wound site, it often leads to delayed healing or chronic wounds. That’s when a collagen product, like Medifil™ II Particles or SkinTemp™ II sheets, can help make a difference by initiating the wound healing process.