Expression of interleukin-1alpha, interleukin-6, and basic fibroblast growth factor by cultured skin substitutes before and after grafting to full-thickness wounds in athymic mice.
OBJECTIVE
Cultured skin substitutes (CSSs), consisting of human keratinocytes and human fibroblasts attached to collagen-glycosaminoglycan substrates, have been demonstrated to cover wounds, and may release detectable quantities of growth factors that promote wound healing.


METHODS
Basic fibroblast growth factor (bFGF), interleukin-1alpha (IL-1alpha), and interleukin-6 (IL-6) were assayed by enzyme linked immunosorbent assay and immunohistochemistry in CSSs in vitro and at days 1, 3, 7, 14, and 21 after grafting to full-thickness wounds in athymic mice.


RESULTS
When isolated cells were tested, IL-1alpha was found to come primarily from the keratinocytes, whereas bFGF was from the fibroblasts. Combinations of both cell types in the CSSs resulted in a synergistic enhancement of IL-6 expression. Quantities of all three cytokines from CSSs were greater in vitro compared with in vivo levels at all time points after grafting. bFGF increased from day 1 to day 7, and then remained relatively constant until day 21. At day 3 maximal levels of IL-1alpha were observed. By day 7, IL-1alpha decreased to approximately 40% of maximal levels, and subsequently increased until day 21. IL-6 levels were highest at day 7 after grafting. All cytokines had reached elevated levels during the time of wound revascularization (days 3-7).


CONCLUSIONS
The sequence of cytokine synthesis in the wounds (i.e., rapid IL-1alpha increase followed by IL-6 expression) parallels serum levels reported after a septic challenge. These findings support the hypothesis that the wound is a source of systemic cytokines.
Goretsky
M J
MJ
Shriners Burns Institute, University of Cincinnati, Ohio 45229, USA.
Harriger
M D
MD
Supp
A P
AP
Greenhalgh
D G
DG
Boyce
S T
ST
D000818:Animals; D001704:Biopolymers; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D016222:Fibroblast Growth Factor 2 / Q000096:biosynthesis / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis / Q000378:metabolism*; D015850:Interleukin-6 / Q000096:biosynthesis / Q000378:metabolism*; D007633:Keratins / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D016038:Skin Transplantation; D017768:Skin, Artificial; D014945:Wound Healing / Q000502:physiology*
D001704:Biopolymers; D007375:Interleukin-1; D015850:Interleukin-6; D016222:Fibroblast Growth Factor 2; D007633:Keratins