Biochemistry

The biochemistry of keloid scars is marked by the following features:

• collagen metabolism:
  • increased collagen turnover
  • increased activity of the synthetic enzymes lysyl oxidase and prolyl-4-hydroxylase
  • increased collagen mRNA expression
  • active keloids synthesise collagen at a rate of 20 times that of normal skin and 3 times that of hypertrophic scars(1)
  • type I and type III collagen synthesis is increased, but the former is increased to a relatively greater extent
  • reduced breakdown of collagen as suggested by the accumulation of collagenase inhibitors alpha-1-antitrypsin and alpha-2-macroglobulin
• increased metabolic rate as suggested by a rise in the activity of enzymes of the glycolytic and TCA pathways

Ref:

(1) Craig RDP, Schofield JD, Jackson JS. Europ J Clin Invest (1975); 5: 69-72.