The skin is a tissue with exceptional properties: mechanical protection, shock absorption, waterproof barrier, sensory function, etc.
Even the slightest damage to the skin caused by injury, burns or surgical incisions can seriously harm the body, so repair is essential.

What are the main stages of healing?

The healing process is complex and not fully understood. However, there are three phases that are more or less related: the inflammatory phase, the proliferation phase, and the tissue remodelling phase.

  • The first phase involves various actors, mainly molecules secreted by several types of cells such as thrombocytes, macrophages and lymphocytes. Skin lesions affect blood vessels, causing bleeding. Platelets form a clot, quickly restoring the skin’s integrity.
  • The second phase involves the formation of new tissue at the site of the wound. The blood clot retracts and collagen-rich tissue appears, invading numerous capillaries. This tissue contains cells responsible for secreting the new components of the skin to be rebuilt, such as collagen (1). In normal skin, type I collagen and type III collagen constitute 80% and 10% of the total collagen present, respectively. In the case of a skin lesion, this ratio is reversed: skin cells mainly synthesise type III collagen (2).
  • The third phase, known as remodelling, determines the final appearance of the scar. It begins when the granulation tissue starts to regress. On average, around the 20th day, the wound closes but remains extremely fragile: the scar’s resistance to stretching is only about 25% of that of normal skin (3). Fibronectin and hyaluronic acid enable the production of a matrix that is more resistant to tensile forces, based on collagen and elastic fibres. This resistance reaches up to 70%. However, scars remain less resistant and less elastic than normal skin due to a less organised matrix and a lack of elastin. During this phase, which can be very long, type III collagen is gradually broken down and replaced by type I collagen, which is more resistant.

How can we heal properly?

Accelerating wound healing and helping new tissue to reorganise quickly is a challenge in medicine, particularly in surgery. This seems all the more pressing when it comes to cosmetic surgery.

  • The importance of nutrition

We already know that an overall unbalanced diet, deficiencies in protein, vitamins and minerals such as iron, obesity and diabetes have a negative impact on healing.

  • Use of collagen

Studies (4) have shown that when wounds in rats were treated with collagen dressings, inflammation was reduced and epithelialisation and healing were accelerated.
In around 20 patients, collagen gel was used on severe leg ulcers that were resistant to conventional treatment methods. Complete healing was achieved in 16 out of 20 cases after a period of 8 to 60 days (5).
Collagen is an essential component of the skin which, when used as a wound treatment, stimulates and recruits immune cells and fibroblasts, etc., thereby promoting healing (6). This wound care therapy provides a targeted approach to the treatment of non-healing wounds by addressing specific molecular defects in healing.

  • The physiological processes of scar healing

Wound healing involves the coordinated interaction of a variety of physiological processes involving bleeding, inflammation, repair cells migrating to and proliferating in the injured area, revascularisation occurring, epithelial continuity being restored, and collagen and other matrix components being synthesised. It is then that wound contraction occurs, and the wound transforms (7). These various functions involved in the healing process are all orchestrated by cytokines and other mediators of cell function.
A study (9) of vitamin C in wound healing in guinea pigs shows the importance of collagen precursors in the first phase of wound healing and that when there is a protein deficiency, there is a lack of building materials, but if there is a deficiency of ascorbic acid (vitamin C), there is a failure to utilise them.

  • Healing problems

In cosmetic surgery, the quality of healing is an important factor. However, it is relative to each individual and unknown.
In addition, some of these operations are performed at an age when skin cells renew themselves more slowly. As the skin loses its elasticity and collagen, it appears less hydrated and more wrinkled. Scars can become red and swollen and be a source of physical and psychological distress. They often require specific, lengthy treatments.
In the case of enlarged scars, scar revision may even be considered, although this is less invasive than the initial procedure.

What supplements are essential?

In Kenji Sato’s study (10), it was demonstrated that ingesting collagen protein hydrolysates has beneficial effects, especially since collagen, an integral part of the skin, plays a key role in the healing process. Its action is enhanced when combined with vitamin C and hyaluronic acid.
Combined with a healthy and varied diet, supplementation with bioavailable collagen can therefore promote physiological healing and restore the integrity of the body’s protective layer.

This report was produced with the expertise of Dr Jo Fontaine, a specialist in nutrition and nutritional supplements with degrees in micro-nutrition, phytotherapy and chronobiology.

Références
  1. Pilcher, B.K., et al., The activity of collagenase-1 is required for keratinocyte migration on a type I collagen matrix. J Cell Biol., 1997. 137(6): p. 1445-57.
  2. Abercrombie M, Flint MH, James DW. (1956) Wound contraction in relation to collagen formation in scurvy-afflicted guinea pigs. J Embryol Exp Morphol 4:167-75.
  3. Lawrence, W.T., Physiology of the acute wound. Clin Plast Surg., 1998. 25(3): pp. 321-40.
  4. Jingjing Chen, Kaili Gao, Shu Liu, Shujun Wang, Jeevithan Elango, Bin Bao, Jun Dong, Ning Liu, Wenhui Wu Fish Collagen Surgical Compress Repairing Characteristics on Wound Healing Process In Vivo
  5. F Daniel, C Foix, R Zaegel; Collagen: physiological approach to skin healing. Its application to the practical treatment of leg ulcers (author’s translation)
  6. Penelope J Kallis, Adam J Friedman PMID: 29601617 Collagen Powder in Wound Healing
  7. W T Lawrence; Physiology of the acute wound
  8. S Trainotti, M Scheithauer PMID: 28695413 DOI: 1007/s00106-017-0381-5 Process, disturbances and improvements of wound healing
  9. Dunphy, J. E.; Udupa, K. N.; Edwards, L. C. Author Affiliation: Dept. Surg., Harvard Med. Sch., Boston, Mass. Journal article: Annals of Surgery 1956 Vol.144 pp.304-316. Wound healing: a new perspective with particular reference to ascorbic acid deficiency.
  10. Kenji Sato 1 PMID: 29114654 DOI: 10.1039/c7fo01275f Food Funct. 13 December 2017;8(12):4325-4330. The presence of food-derived collagen peptides in human body structure and biological activity