Chemokine and inflammatory cytokine changes during chronic wound healing

Abstract

Wound healing is a complex process resulting from an interplay of processes including coagulation, inflammation, angiogenesis, and epithelialization. The chemokine family has been shown to contain members that are potent regulators of many of these pathways. Because we have previously shown that chemokines "pool" in biologic wound dressings, we studied the levels of CXC and CC chemokines, along with key inflammatory mediators, serially from a group of patients undergoing therapy for chronic venous leg ulcers. After 8 weeks, all patients had marked clinical healing of their ulcers (median 63.3% reduction in size) with two of 10 completely healed. Wound fluids extracted from dressings showed high levels of platelet factor-4 and interferon-gamma-inducible protein, with a trend toward increases in the ratio of the sums of the angiogenic versus angiostatic CXC chemokines (p = 0.082) in the tissues collected from the center of the ulcers during wound closure. Neutrophil-activating peptide-2 and interleukin-8 accounted for the most changes in wound fluid angiogenic chemokines, with significant differences both as compared with baseline levels and with patients' plasma level noted at various time points between weeks 0 and 8. The level of angiostatic chemokines, interferon-y inducible protein 10 and platelet-activating-4, fell most significantly between weeks 0 and 3 as compared with plasma levels. The observed shift toward angiogenic CXC chemokines suggests that effective healing in chronic venous insufficiency ulcers appears to "move" the ulcer bed toward a state more conducive to epithelialization,characteristic of the proliferative phase of wound healing. CC chemokines were also elevated at baseline in the wound fluid samples as compared with the patients' plasma levels. Macrophage inflammatory protein-1 (3 and regulated on activation, normal T expressed and secreted (RANTES) levels decreased with healing, whereas there were significant increases in the tissue levels of monocyte chemoattractant protein-1 and macrophage inflammatory protein-1 a over the first 4 weeks of therapy (p< or = 0.05 for both). Coincident with these changes was a steady increase in the ratio of interleukin-1 R/interleukin-1 receptor antagonist protein in the ulcer center tissues, which also correlated with healing (p < 0 .05) as compared with a decreasing ratio at the ulcer edge, and a biphasic response in the wound fluids. These findings suggest that advanced wound care techniques help move the ulcer from a chronic inflammatory state into one more characteristic of the late inflammatory/early proliferative phase of wound healing. Chemokines may play a critical role in the pathogenesis of chronic venous ulcers through their effects on angiogenesis and/or the progression of inflammatory reactions at the site of injury.

Chemokine Involvement in Fetal and Adult Wound Healing

“…They share 20-50% homology in amino acid sequence, 2,9 including the presence of cysteine residues in conserved locations that determine their shape. 10 They are classified into four families based on the number and positioning of the cysteine residues: C, CC, CXC, and the CX 3 C (Fig.…”

“…11 Members of the CXC group share two conserved cysteines separated by an amino acid. 9 The CXC family is further divided into two groups based on the presence of glutamic acid (E), leucine (L), and arginine (R) immediately before the first cysteine. This ELR + sequence is important for receptor selectivity and binding.…”

Wound Fluid Diagnostics in Diabetic Foot Ulcers

“…In the past, this particular technique has frequently been modified. Protocols describing the extraction of fluids directly from dressings have been reported multiple times (Fivenson et al 1997;Seah et al 2005). For example, wound exudate trapped in a foam dressing has been obtained by squeezing the dressing material through a syringe (Seah et al 2005).…”

Quantification of MSCs involved in wound healing: use of SIS to transfer MSCs to wound site and quantification of MSCs involved in skin wound healing

“…TNF-a and IL-1b are pro-inflammatory cytokines. IL-4 and IL-10 are anti-inflammatory cytokines (Bryan et al, 2005;Fivenson et al, 1997). Figure 5B shows the RNA expression levels of TNF-a and IL-1b peak on D3 for control and for SIS + MSCs on days 5 and 7, respectively, TNF-a and IL-1b of the SIS + MSCs were lower than those of control over 10 days.…”