Wound exudates are considered liquid biopsies of wounds and contain the pathogenic drivers of chronicity. Previous studies have shown elevated levels of pro-inflammatory cytokines and proteases in chronic wound exudates.
We obtained 78 wound exudates harvested by negative pressure therapy and compared their levels of 16 cytokines and chemokines, 11 growth factors, 8 metalloproteinases, determined by multiplex analysis, and their enzyme activities of myeloperoxidase, elastase and metalloproteinase. The wounds included healing and non-healing venous, arterial, pressure and diabetic ulcers as well as healing surgical wounds.
Hepatocyte growth factor, the cytokines IL-1 alpha, IL-1 beta, TNF-alpha and CXCL10 as well as metalloproteinases 1, 2, 3, 8, 9, and 12 were elevated in wound exudates of non-healing wounds. Enzyme activities were also increased in non-healing wounds. However, due to the large patient-to-patient variability of these data, the numerical values of any of these parameters do not permit the distinction between healing and non-healing wound phenotypes in individual patients. Only the analysis of consecutive samples of the same patient allowed the detection of differences corresponding to the healing process.
In conclusion, wound exudate levels of cytokines, proteases and growth factors are insufficient to distinguish between healing and non-healing wounds.

Comparative analysis of cytokines, proteases and growth factors in human wound exudates obtained by vacuum therapy