From:  Impaired cytokines in diabetes and diabetic foot ulcers: mechanisms and prospects

 Role of various cytokines in the pathogenesis of diabetic foot ulcers.

Cytokine/PathwayMolecular and cellular effectsMechanism
IL-6, IL-1β, TNF-α, IL-8 [43]Prolongs inflammation, decreases angiogenesis, and alters ECM remodeling. Persistent inflammation, disruption of normal healing.Pro-M1 activation (promotes inflammation).
TNF-α (↑), IL-10 (↓) [42]Imbalance leads to innate immune defects.
IL-10 secreted from Treg cells plays a role in M2 activation.
Defective transition, prolonged M1 phase, little to no M2 involvement.
Imbalance prevents the M2 pathway from becoming activated and prolongs M1 activation.
NF-κB [44]Master-regulatory Inflammatory pathway.
Activation leads to increased TNF-α secretion.
Prolonged inflammation and ECM degradation.
Activated by hyperglycemia, AGEs, and oxidative stress.
Upregulates TNF-α, IL-1β, IL-6, and MMPs.
IFN-γ [45]Prolongs inflammation
Impaired wound healing
Stimulates TNF-α and IL-1β by
Macrophages.
IFN-α/β [45]Type I interferons are linked to impaired healing.
Reduced angiogenesis and delayed granuloma formation.
Suppresses VEGF limits vascularization.
IFN-κ [46]Promotes wound repair when restored.
Accelerates closure in preclinical models.
Enhances re-epithelialization and collagen organization.
IL-6, IL-1β, TNF-α [43]Inflammatory mediators linked to chronicity.
Restores normal inflammatory timing and reduces chronic inflammation.
Prolonged cytokine peaks; NPWT shifts peak earlier.
TNF-α, IL-β, IL-6 [43]ChronicM1 activation, inflammation, and delayed healing.Persistent elevation leads to ECM degradation and a repair block.
IL-10, TGF-β, IGF-1 [44]M2-associated markers: impaired angiogenesis, repair, and Treg promotion.Suppressed in DFUs.

AGEs: advanced glycation end products; DFUs: diabetic foot ulcers; ECM: extracellular matrix; IFN: interferon; IGF: insulin-like growth factor; IL: interleukin; MMPs: matrix metalloproteinases; NPWT: negative pressure wound therapy; TGF: transforming growth factor; TNF: tumor necrosis factor; VEGF: vascular endothelial growth factor.