influence of aging on biological properties of periodontal ligament cells the majority of patients eligible for periodontal regenerative therapies are aged subjects since periodontal ligament cells pdlc are essential for periodontal regeneration the aim of the present study was to determine the effect of cellular aging on pdlc including genes associated with extracellular matrix metabolism and growthassociated factors pdlc cultures were obtained from subjects aged 15 to 20 years and subjects aged more than 60 years proliferation cell viability mineralization assays and mrna levels were assessed for type i and iii collagen plateletderived growth factor pdgf1 basic fibroblast growth factor bfgf metalloproteinase mmp2 and8 and tissue inhibitor of metalloproteinases timp1 and2 data analysis demonstrated that aging negatively influenced cell proliferation and mineral nodule formation p 005 in addition mrna levels for type i and iii collagen were significantly lower in aged cells p 005 whereas mmp2 and8 and timp1 mrna levels were higher p 005 within the limits of the present study data analysis suggests that aging modulates important biological properties of periodontal ligament cells diminishes the potential for mineral nodule formation and favors extracellular matrix degradation