Introduction

Collagen is a natural fibrous protein of the extracellular matrix.¹ It contains three proteins wrapped around each other to form a triple-helix structure.² Collagen is a biocompatible structural protein that is ideal for tissue engineering and regenerative purposes.³

Actions and Benefits of Collagen Dressings in Wound Healing

Collagen fibers influence a cellular response regulated by integrin; this is achieved through the biological process of fibrillogenesis. Fibrillogenesis comprises collagen network formation and interaction within the cellular level. The fibers cross-link to stabilize and sustain bioactivity and bioavailability.² Fibroblasts enhance the structure support and protein scaffolds of the extracellular matrix.⁴

Collagen-based biomaterials stimulate specific cells, such as macrophages and fibroblasts, that positively impact wound healing. These materials can provide moisture or absorption, depending on the delivery system.⁵ Rather than attempting to control the wound’s macroenvironment as other dressings do, collagen dressings target specific defects in the chronic wound healing environment and promote healing at the biochemical level by manipulating wound biochemistry. They correct imbalances in the wound microenvironment.⁵ Collagen dressings impact all phases of wound healing, including⁴:

• Hemostasis: After an injury, the interaction between broken collagen and platelets leads to activation of the clotting cascade.
• Inflammation: Proteases break the collagen into small fragments, a process that stimulates the migration of inflammatory cells to the wound bed.
• Proliferation: Fibroblasts deposit endogenous collagen; vascular endothelial cells form granulation cells, and keratinocytes aid re-epithelialization.
• Remodeling: Collagen fibers mature, rearrange, and align to create a bridge between the borders of the damaged tissue.

Collagen Products Available for Wound Care

There are 16 types of collagen found naturally, although the types most frequently used for collagen dressings are type 1 and a combination of type 1 and denatured collagen. Type 1 collagen accounts for approximately 80% to 90% of the body’s collagen and provides structure to skin, bones, tendons, connective tissue, and teeth.⁶ Many of the collagen products available contain bovine, ovine, equine, avian, piscine, or porcine collagen that has been treated to make it non-antigenic.³

Oxidized regenerated cellulose, a plant-based material, can be combined with collagen to produce a dressing that is capable of binding to and protecting growth factors by binding and inactivating matrix metalloproteinases in the wound environment.⁵ Various collagen technologies have been paired with additional ingredients such as alginate, hydrogel, silver, polyhexamethlene biguanide (PHMB), carboxymethyl cellulose (CMC), and ethylenediaminetetraacetic acid (EDTA).⁷

Numerous different collagen dressings are available. These dressings may use different carriers and combine agents, such as gels, pastes, polymers, and oxidized regenerated cellulose. Collagen may vary in type and source, and some types are combined with silver to enhance bioburden management further.⁵ During manufacturing, the integrity of collagen can be altered or destroyed. Denatured collagen, or that which has lost its triple-helical formation, does not easily interact with host tissue, and fibroblasts may not migrate significantly.⁴ Ideally, collagen dressings work best when⁴

• Their native structure is intact rather than denatured, altered, or cross-linked.
• They contain the highest amount of collagen content.
• Are composed solely or primarily of type 1 collagen.

Conclusion

When choosing a collagen dressing, it’s crucial to consider cost, the type of collagen it contains, the way the dressing has been manufactured, and how it provides a reduction of proteolytic enzymes and a scaffold for healing. It’s also essential to understand the unique needs of the wound itself. These dressings may additionally provide anti-infective, anti-inflammatory, antifibrotic, and analgesic properties, depending on the unique wound characteristics.⁵

References

1. Kathula RP, Rekha B, Kathula H. Comparative study between collagen dressings with non-collagen dressings on clean surgical wounds. IAIM. 2020;7(10):5-8.
2. Wu S, Applewhite AJ, Niezgoda J, et al. Oxidixed regenerated cellulose/collagen dressings: review of evidence and recommendations. Adv Skin Wound Care. 2017;30(11(Suppl 1):S1-S18.
3. Naomi R, Fauzi MB. Cellulose/collagen dressings for diabetic foot ulcer: a review. Pharmaceutics. 2020;12(9):881. doi: 10.3390/pharmaceutics12090881.
4. Sherman R. Are all collagen dressings the same? Knowing the difference makes all the difference. 2019. https://www.biologiq.nl/wp-content/uploads/2019/08/Are-all-collagen-dre…. Accessed December 20, 2020.
5. Fleck CA, Simman R. Modern collagen wound dressings: function and purpose. J Am Col Certif Wound Spec. 2011;2(3):50-54..
6. Lodish H, Berk A, Zipursky SL, et al. Collagen: the fibrous proteins of the matrix. In: Molecular Cell Biology. 4th ed. New York, NY: W.H. Freeman; 2000. https://www.ncbi.nlm.nih.gov/books/NBK21582/. Accessed January 5, 2021.
7. What you need to know about collagen wound dressings. 2017. https://woundcareadvisor.com/what-you-need-to-know-about-collagen-wound…. Accessed January 19, 2020.