Effect of Aging on Functional Changes of Periodontal Tissue Cells

Abstract

Although the severity of periodontal disease is known to be affected by age, functional changes of periodontal tissue cells during the aging process are not well characterized. It is important to define how cellular aging affects the progression of periodontal diseases associated with the aging process. In vitro aging of human gingival fibroblast (HGF) and periodontal ligament fibroblast (HPLF) cells was prepared by sequential subcultivations (5 to 6 passages as young, 18 to 20 passages as old). GFs were also prepared from gingiva of Down's syndrome patients and 60-week-old rats. Fetal rat calvarial osteoblasts were prepared by sequential digestion with collagenase. HGF and HPLF cells were treated with lipopolysaccharide (LPS) and cyclic tension force, respectively. Amounts of PGE2, interleukin (IL)-1 beta, IL-6, and plasminogen activator (PA) in conditioned media were measured. Total RNA was extracted, and mRNA expression was analyzed by reverse transcription polymerase chain reaction (RT-PCR). LPS-stimulated PGE2, IL-1 beta, IL-6, and PA production was increased in "old" HGF compared to younger cells. According to RT-PCR analysis, gene expression of COX-2, IL-1 beta, IL-6, and tissue type (t) PA was higher in old cells than in young cells. Cyclic tension force to HPLF also stimulated phenotypic and gene expression of IL-1 beta, PGE2 (COX-2 gene) and tPA. These findings suggest that aging in both HGF and HPLF may be an important factor in the severity of periodontal disease through higher production of inflammatory mediators in response to both LPS and mechanical stress. In addition, oxygen radical-treated fibronectin (FN) as substratum diminished bone nodule formation by osteoblasts when compared with intact FN. This finding suggests that FN plays an important role in Osteoblast activity and that FN damaged by oxygen radicals during the aging process may be related to less bone formation.

Effects of Human Ageing on Periodontal Tissues

“…There are phenotypic subpopulations of fibroblasts with different functions in the synthesis and maintenance of extracellular matrix constituents 10 . In vivo and in vitro studies have shown functional and structural alterations in fibroblasts associated with ageing 6,[11][12][13] . Gingival fibroblasts (GF) may be constantly affected by oral bacteria and their products, such as the lipopolysaccharides (LPS), present in their cell walls.…”

“…Gingival fibroblasts (GF) may be constantly affected by oral bacteria and their products, such as the lipopolysaccharides (LPS), present in their cell walls. The LPS induces GF to release some inflammatory cytokines such as prostaglandin E 2 (PGE 2 ), interleukin (IL)-1 , and plasminogen activator (PA) 6,14 . The influence of these inflammatory mediators on both GF and periodontal ligament fibroblasts (PLF) might account for the severity of periodontal disease 6 .…”

“…The LPS induces GF to release some inflammatory cytokines such as prostaglandin E 2 (PGE 2 ), interleukin (IL)-1 , and plasminogen activator (PA) 6,14 . The influence of these inflammatory mediators on both GF and periodontal ligament fibroblasts (PLF) might account for the severity of periodontal disease 6 . Quantitative differences in protein synthesis were found in young and old gingival fibroblasts in vitro.…”

“…These alterations must be understood to differentiate pathological conditions from the altered physiology of oral tissues resulting from ageing 5 . Some studies in humans and animals have demonstrated that alterations in periodontium dynamics occur with age 6,7 . In spite of the fact that the periodontal disease severity is known to be associated with age, functional changes in periodontal tissue cells during the ageing process have not been well characterized 8 .…”

“…In spite of the fact that the periodontal disease severity is known to be associated with age, functional changes in periodontal tissue cells during the ageing process have not been well characterized 8 . It is important to define how cellular ageing affects the progression of periodontal diseases associated with ageing 6 . The understanding of the influence of human aging in the dynamic of the inflammatory process in patients with periodontal disease may help in the treatment planning of these patients.…”