title: Histological increase in inflammatory infiltrate in sun-exposed skin of female subjects: the possible involvement of matrix metalloproteinase-1 produced by inflammatory infiltrate on collagen degradation.
abstract: 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.
authors.affiliation: Biological Science Laboratories, Kao Corporation, Tochigi, Japan. 388831@kastanet.kao.co.jp
authors.forename: T
authors.initials: T
authors.lastname: Hase
authors.forename: K
authors.initials: K
authors.lastname: Shinta
authors.forename: T
authors.initials: T
authors.lastname: Murase
authors.forename: I
authors.initials: I
authors.lastname: Tokimitsu
authors.forename: M
authors.initials: M
authors.lastname: Hattori
authors.forename: R
authors.initials: R
authors.lastname: Takimoto
authors.forename: R
authors.initials: R
authors.lastname: Tsuboi
authors.forename: H
authors.initials: H
authors.lastname: Ogawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003094:Collagen / Q000378:metabolism*; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D007223:Infant; D020781:Matrix Metalloproteinase 1 / Q000502:physiology; D008875:Middle Aged; D011832:Radiation Injuries / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D012867:Skin / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D015595:Skin Aging / Q000276:immunology / Q000473:pathology* / Q000502:physiology; D013472:Sunlight / Q000009:adverse effects*; D016176:T-Lymphocyte Subsets / Q000201:enzymology / Q000473:pathology
chemical_list: D003094:Collagen; D020781:Matrix Metalloproteinase 1