Figure 2.

Chronic wound healing. In chronic wounds there is increased reactive oxygen species production and interruption of nitric oxide synthase, leading to ischemia and nerve cell damage. There is also reduction of progenitor cells influx, proliferation, and release of growth factors, accompanied by a chronic inflammatory state and impaired new vessel formation. There is also a delay in the production of chemokines, increased of cytokines and abnormal activation of macrophages. In addition, chronic wounds often suffer the damaging effects of microbes that can form thick biofilms, which increase wound adhesion, immune deficiency, and local resistance to antibiotics. Color images are available online.