ISSN:
1365-2133
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
To investigate morphological changes occurring during cutaneous photoageing, a correlation between the number of infiltrating cells in the dermis and the degree of collagen damage was examined using sections from clinically normal chronically sun-exposed and sun-protected skin of Japanese female subjects. Haematoxylin and eosin-stained sections from 134 sun-exposed (subjects aged 3–82 years) and 73 sun-protected (subjects aged 1–86 years) areas demonstrated a predominant lymphoid cell and to a lesser extent histiocyte infiltration. The mean ± SD number of lymphoid cells and histiocytes in the sun-exposed skin sections (427·0 ± 192·2 and 147·8 ± 83·3 cells/mm2, respectively) was significantly higher than in the sun-protected skin sections (292·6 ± 98·3 and 125·9 ± 59·0 cells/mm2, respectively) (P 〈 0·001 and P 〈 0·05, respectively), and the number of lymphoid cells in the sun-exposed skin sections increased significantly with age up to 50 years (r = 0·400, P 〈 0·001). Sun-exposed skin sections with severe collagen degeneration had a significantly higher number of lymphoid cells than those with slightly degenerated collagen (mean 626·3 vs. 482·4 cells/mm2, P 〈 0·01). The mean count of mast cells in sun-exposed skin was 202·0 cells/mm2; this did not vary with the age of the subjects or the level of collagen damage. Immunohistochemical studies using 24 frozen sections identified most of the lymphoid cells infiltrating sun-exposed skin as memory T lymphocytes (CD3+, CD4+ and CD45RO+). The number of cells which displayed immunoreactivity to matrix metalloproteinase (MMP)-1 in the sun-exposed skin sections was significantly higher than in the sun-protected skin sections (mean 170·2 vs. 113·6 cells/mm2, P 〈 0·05). Among these cells were observed CD3 and MMP-1 double-stained T lymphocytes, and T lymphocytes contacting MMP-1-positive cells. These morphological observations suggest that T lymphocytes infiltrating photodamaged skin may play a part in the degeneration and reduction of collagen through MMP-1 activity.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1365-2133.2000.03296.x
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