Granulation Tissue

Granulation tissue is the provisional repair tissue filling an open wound defect during the proliferative phase, typically appearing from around day three to five. Its name comes from the granular look of the wound bed, which is the cut ends of dense capillary loops. Histologically it mixes proliferating fibroblasts and myofibroblasts, abundant macrophages and new vessels in a loose matrix of fibrin, fibronectin, hyaluronan and disproportionately type III collagen. Epithelium cannot cross a defect without it: keratinocytes advance over the granulation surface while myofibroblasts pull the margins together underneath.

Its appearance is diagnostic in wound care. Pale, dusky or absent granulation points to inadequate perfusion, high bacterial bioburden or biofilm, none of which a topical growth factor corrects. The one growth factor product approved to stimulate it, becaplermin, a recombinant PDGF-BB gel approved in 1997 for diabetic foot ulcers, shows the tradeoff: a boxed warning for increased cancer mortality with repeated tube use was added in 2008 after post-marketing analysis.

For evidence purposes granulation is a process measure, not an outcome. What matters is complete closure, time to closure, and recurrence or amputation rates. A wound that granulates well and does not epithelialise has not healed.

The error that shows up constantly is the before-and-after wound photograph. Granulation appearance improves markedly with debridement, offloading, moisture balance and infection control, all of which normally happen alongside whatever product is credited, and photographic assessment is sensitive to lighting, angle and wound preparation. Uncontrolled photographic series are the main evidence offered for topical repair peptides, and they cannot separate the compound from the dressing change.