The Evolution of Wound Healing

Abstract

Man’s struggle to heal wounds is as old as history itself. As life forms evolved from single cell life to amphibian and finally mammal, the pristine ability to heal by regeneration was lost and thus repairs by inflammation and subsequent deposition of matrix protein (scar) evolved as the method of mammalian healing. This evolutionary change leading to scar (the deposition of collagen) seems to be the key to preventing regeneration. It is well known that when the point is reached on the ladder where regeneration on longer occurs, inflammation and collagen deposition are the difference. In fact, if one takes a form of life, which seems the first link between regeneration and scar formation and a collagen cross-linking inhibitor is fed to the animal, then regeneration will once again occur! If we could only bridge this gap, imagine how successful we could become in the management of diabetic wounds. Although uncertain regarding why this occurred in the evolutionary process, it is hypothesized that as mammals became sophisticated, they needed rapid healing to protect themselves from other predators and to eke out a physical survival in a very hostile environment. In early-recorded history, the Egyptians repaired wounds with primitive suture materials (such as insect claws) and used clean sheets on surgical fields to prevent “suppuration.”; The Greeks, led by Hippocrates, devised methods of treatment for primary wounds and chronic wounds. They used various gauze materials empirically which included wine, milk, honey, and other substances in open wounds similar to our treatment today. Today, one can assign scientific rationale to some of these ancient empirical choices. For example, the complex sugars of honey are known to suppress the growth of Gram-positive bacteria. Wine will suppress pseudomonas proliferation. Milk products may contain cytokines or serve as buffers to control wound pH. Although the ancients had no idea that pus was actually is made up of proteins and dead leukocytes, they understood that drainage of localized products of infection was a good sign (laudable pus). They understood that when signs opf inflammation could not be localized that death would inevitably follow. During the early Roman era, Celsius, unaware of the existence of bacteria, did recognize and describe the cardinal signs of clinical infection being (1) rubor—erythema, (2) tumor—swelling, (3) dolor—pain, and (4) calor—heat.