Are Fibrocytes Present in Pediatric Burn Wounds?

Abstract

Objective of the study is to investigate for the presence of fibrocytes, a leucocyte found at sites of injury with fibroblast-like properties, within pediatric burn wounds. Seventy 3 mm punch biopsies were taken from 53 burn wounds in 33 children between 7 months and 15 years of age at the time of planned operative debridement and grafting. After fixation and sectioning, immunohistochemistry (IHC) staining was performed for CD34, pro-collagen I, alpha smooth muscle actin, transforming growth factor beta1 and Leucocyte Specific Protein-1 (LSP-1). The presence of fibrocytes was confirmed by double immunofluorescence staining with antibodies to CD34 or LSP-1 with pro-collagen I. CD34 positive cells were present in all burn wound biopsies. Using IHC staining, in 18 patients cells positive for CD34 and pro-collagen I were identified; in 17 patients, cells positive for CD34 and alphaSMA and in 17 patients also cells positive for LSP-1 and pro-collagen I. Double immunofluorescence for CD34/pro-collagen I and LSP-1/pro-collagen I confirmed the presence of fibrocytes in specimens from 17 of 18 patients positive for these markers on IHC. Of the 17 patients whose burn wounds were complicated by hypertrophic scarring, fibrocytes were identified in 88% (n = 15) compared with 18% of those without hypertrophic scarring (P < .001). This study represents the first report of the presence of fibrocytes in acute pediatric burn wounds. These cells appear to be involved in the local response to burn wound injury and may correlate with the later development of hypertrophic burn wound scarring.

Monocyte M1/M2 profile is altered in paediatric burn patients with hypertrophic scarring

“…That circulating fibrocytes were low in all groups and did not differ between controls and burn groups, or between HTS and NoHTS groups, was surprising in light of evidence linking tissue fibrocyte proportions to burns and scarring. Our own observations revealed that fibrocyte presence was higher in paediatric HTS tissue samples than NoHTS samples 9 and others have shown the same in adult HTS. 10 We propose that changes in the circulation are more subtle than that in the tissue.…”

“…A related monocyte‐derived cell type, fibrocytes, is likewise associated with HTS. Work by our group and others shows higher fibrocyte numbers in HTS tissue compared to non‐HTS tissue after burns 9,10 …”

“…Work by our group and others shows higher fibrocyte numbers in HTS tissue compared to non-HTS tissue after burns. 9,10 While dynamics of macrophages and fibrocytes within the skin after wounding may give insight into scarring outcome, obtaining biopsies as a means of predicting healing is not feasible in children. Their precursors, circulating monocytes, in contrast are readily accessible and may provide insight into healing.…”

The biology of burn injury

“…Another recent study concluded that fibrocytes are present in abundance in acute burn wounds, and these cells appear to be involved in the local response to burn wound and may correlate with the later development of hypertrophic burn wound scarring. This might be very important in the future to predict those who will develop hypertrophic scar (15). A potential promising new approach for wound healing and treatment involves the use of stem cells for skin regeneration.…”

First Identification of Resident and Circulating Fibrocytes in Dupuytren’s Disease Shown to Be Inhibited by Serum Amyloid P and Xiapex

“…Fibrocytes have been previously studied in hypertrophic scarring; another form of fibroproliferative dermal wound healing. Yang et al showed a twofold increase in fibrocytes in the hypertrophic scar of burn patients compared with normal skin and mature skin scars, and further work revealed the number of fibrocytes correlated with burn severity [25]–[27]. We have recently shown the presence of fibrocytes in keloid disease tissue on the basis of combination of inflammatory markers [28].…”