AGE-RELATED DIFFERENCES IN THE TEMPORAL AND SPATIAL REGULATION OF MATRIX METALLOPROTEINASES (MMPS) IN NORMAL SKIN AND ACUTE CUTANEOUS WOUNDS OF HEALTHY HUMANS
Gs. Ashcroft et al., AGE-RELATED DIFFERENCES IN THE TEMPORAL AND SPATIAL REGULATION OF MATRIX METALLOPROTEINASES (MMPS) IN NORMAL SKIN AND ACUTE CUTANEOUS WOUNDS OF HEALTHY HUMANS, Cell and tissue research, 290(3), 1997, pp. 581-591
Despite the association of increasing age with chronic wound-healing d
isorders and an impaired rate of healing of acute cutaneous wounds, th
e role of matrix metalloproteinases (MMPs) is unknown. To determine th
e spatial and temporal patterns and activities of MMP-1, -2, -3 and -9
, 132 healthy humans aged between 19 and 96 years underwent 4-mm punch
biopsies followed by wound excision between day 1 and day 180 postwou
nding. Wounds showed an age-related increase in MMP-2 and MMP-9 immuno
staining from day 3; this was associated with degradation of gelatin a
s shown by zymograms and with increased proteinase activity as shown b
y azocoll assays. Distinct spatial localisations for each MMP were obs
erved: MMP-2 was found in epidermal structures; MMP-9 was observed in
inflammatory cells up to day 21; MMP-1 was localised to keratinocytes
at the wound margin. Normal old skin showed pro-MMP-2 bands on zymogra
phy and increased MMP-2 immunostaining. These results indicate that: (
1) intrinsic ageing is associated with the up-regulation of MMPs previ
ously associated with chronic wound healing; (2) wound-tissue proteina
ses are essentially active up to day 21 postwounding; and (3) intrinsi
c ageing may predispose to tissue breakdown disorders because of MMP-2
up-regulation in normal skin.