Histological Assessments

Cellular Profile of Wound Tissue

Under normal “uncompromised” circumstances skin wounds are “seen” to progress through the stages of inflammation, new tissue formation and new tissue remodelling - which results in the formation of scar tissue (a virtually avascular & acellular tissue functionally and aesthetically inferior to normal skin).

The cellular profile of wound tissue changes with time after injury.

Initially, inflammatory cells that are responsible for clearing wound site debris (such as neutrophils and monocyte-macrophages) predominate; later as the wound heals (matures) proliferative cells which are responsible for the generation of replacement tissues (i.e. fibroblasts & endothelial cells) predominate.

Consequently, the cellular profile of a wound can be used to describe its maturity. Wound tissues with a relatively high proportion of inflammatory cells are considered less mature (less advanced) than similar tissues containing relatively few inflammatory cells.

The relative contribution of inflammatory cells (neutrophils & monocyte-macrophages) and proliferative cells (fibroblasts & endothelial cells) to wound cellularity—at a given point in time after injury and treatment — allows the impact of an investigational agent on wound progression to be determined.

Cell specific histological staining techniques are used to label and measure the involvement of specific cellular lineages (see below).

Scar Assessment

Scar Tissue Analysis is performed using our in house Cica Scar Analysis System (C-SAS)

C-SAS generates data describing the directionality of collagen bundles within scar dermal tissue.

The output generated by C-SAS describes the directionality of collagenous structures in twelve 15° segments (see graphic).

Scar tissue is composed of a collagen bundles largely orientated parallel to the surface of the skin; whereas, normal skin has a more multi-directional structure.

Severe scars have more horizontally-orientated structures; less severe scars display a greater variation in directionality.

Routine H&E staining of a diabetic wound showing histological planimetry measurements:

a) Granulation tissue depth

b) Epithelial coverage

c) Open wound

d) Wound width measurement

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