[Decreased stimulation of hyaluronic acid synthesis by PDGF, IGF-I or serum in the aging process of skin fibroblasts in vitro].
Human skin fibroblasts of phase II ("young" cells derived from populations with a low population doubling level) and of phase III ("old" cells from populations, which were approx. 2 population doublings before the last possible subculture) were kept under subconfluent conditions in a defined serum-free medium. Thereby the cells are in a non-proliferative "quiescent" state. Glycosaminoglycan (GAG)- and especially hyaluronan (HA)-synthesis and release into the medium were investigated by the incorporation rate of 14C-glucosamine. About 95% of the synthesized (48 h) GAGs and HA were medium-released and 5% cell-bound. HA synthesis rate of phase III-cultures was significantly reduced, as compared with phase II-cultures. Stimulation of HA-synthesis of phase III-cells--in comparison with phase II-cells--by serum, PDGF or IGF-I was strongly reduced. While HA-synthesis of phase II-cells was maximally stimulated by 5% FCS or 20 ng/ml PDGF, phase III-cells dit not exhibit a saturation kinetics up to 20% FCS or 60 ng/ml PDGF. The strongly reduced HA-synthesis rate of phase III-cells--compared with phase II-cells--in the non-stimulated quiescent state as well as after stimulation by PDGF, IGF-I or serum might be considered as a biomarker of in vitro (and in vivo?) ageing.
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Institut für Physiologische Chemie, Philipps-Universität Marburg, Germany.
Freudenstein
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D000328:Adult; D001798:Blood Proteins / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D002460:Cell Line; D016922:Cellular Senescence / Q000502:physiology*; D003470:Culture Media; D005347:Fibroblasts / Q000166:cytology; D006801:Humans; D006820:Hyaluronic Acid / Q000096:biosynthesis*; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D008297:Male; D010982:Platelet-Derived Growth Factor / Q000502:physiology*
D001798:Blood Proteins; D003470:Culture Media; D010982:Platelet-Derived Growth Factor; D007334:Insulin-Like Growth Factor I; D006820:Hyaluronic Acid
Verminderte Stimulierbarkeit der Hyaluronsäuresynthese durch PDGF, IGF-I oder Serum in der Alterungsphase von Hautfibroblasten in vitro.