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There is a great deal of interest in the understanding of possible age-related changes in Mesenchymal Stem Cells in view of their use for regenerative medicine applications. Given to the outmost standing of periosteum in bone biology and to probe data for a cell-based therapy promoting graft osseointegration in the elderly, we tried to identify specific aging markers or pattern of expression in human periosteal precursor cells. Immunohistochemical detection of Ki67 and p53, Nitric Oxide production and qRT- PCR of a selected gene panel for osteoblastic differentiation, bone remodeling and stemness were evaluated. We confirmed that both Ki67 and p53 are noteworthy indicators of senescence in human periosteal precursor cells and their expression significantly correlate with cell NO production. Moreover, cell age affects genes involved in bone remodeling, with a significant increase in interleukin-6 mRNA expression and receptor activator of nuclear factor kappa-B ligand/osteoprotegerin ratio. The analysis of mRNAs of genes involved in pluripotency regulation and self-renewal of stem cells, evidenced changes at least in part related to bone remodeling. We believe that this is the first study taking on age-related changes in human periosteal precursor cells, and paving the way toward new regenerative medicine strategies in bone aging and/or bone metabolic diseases.

The aim of the present study was to investigate if aging is associated with platelet membrane modifications possibly related with cellular activation and hyperaggregability and if platelets from centenarians show different properties which might play a role in successful aging and longevity. Platelet plasma membranes were obtained from 60 healthy subjects, divided into four groups according to the age range: (1) 21-39 years; (2) 40-59 years; (3) 60-79 years; (4) centenarians (>/=100 years). Both centenarians and control subjects were submitted to the following inclusion criteria: liver, kidney, and thyroid function tests within the normal range; absence of history of diabetes, hypertension or coronary heart disease; no signs of edema or dehydration; no drug or vitamin supplement in the 4 weeks before the study; absence of Alzheimer's disease or secondary dementia. The following determinations were performed: lipid peroxide levels (Lp) evaluated by the measurement of thiobarbituric acid (TBA) reactivity, fluidity studied by the fluorescence anisotropy of the probe 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH), Na(+)/K(+)-ATPase activity measured by the method of Kitao and Hattori, and sialic acid (SA) content evaluated by the periodate-thiobarbituric acid method. Centenarians showed: (i) Lp concentrations lower than elderly subjects; (ii) increased Na(+)/K(+)-ATPase activity compared with adult and elderly subjects; (iii) higher TMA-DPH anisotropy than elderly subjects; (iv) SA content similar to the young and adult groups.The present work found deep platelet membrane modifications in centenarians compared with elderly subjects. These changes are likely associated with a decreased platelet activation and therefore might exert a protective role against cardiovascular accidents, as platelet activation is a key event in the initiation and progression of arteriosclerosis.

The plasma membrane composition affects intracellular processes and the cellular susceptibility to free radical attack, which has been associated with the impairment of cellular functions occurring during senescence. The study of the modifications of the plasma membrane in centenarians might elucidate the biological mechanisms at the basis of longevity and successful aging. The work was performed in 190 subjects, divided into five groups according to the age range: (1) 21-40 years (n=25); (2) 41-60 years (n=30); (3) 61-80 years (n=30); (4) 81-99 years (n=50); and (5) centenarians (> or = 100 years) (n=55). The following determinations were performed on erythrocyte membranes: (i) the lipid peroxide level (Lp) evaluated as malondialdehyde content; (ii) susceptibility to in vitro oxidation evaluated as difference in the content of thiobarbituric acid-reactive substances before and after phenylhydrazine addition; (iii) unsaturated/saturated fatty acid ratio and individual polyunsaturated fatty acid composition measured by gas chromatography; and (iv) fluidity studied by means of the anisotropy of the probe 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH). Erythrocyte membranes from centenarians showed: (i) decreased basal lipid peroxide levels and reduced susceptibility to peroxidation in comparison with elderly subjects; (ii) increased unsaturated/saturated fatty acid ratio in comparison with every other age group; (iii) higher levels of eicosapentaenoic and docosahexaenoic acid and reduced content of linoleic and arachidonic acid in comparison with elderly subjects; and (iv) decreased anisotropy of TMA-DPH, i.e. higher fluidity compared with all the other age groups. In conclusion, the present work demonstrates that erythrocyte membranes from centenarians show some distinct features in comparison with elderly subjects that might act in a protective way against injuries.

Human whole saliva contains a number of antimicrobial agents, and lysozyme, lactoferrin, secretory IgA and peroxidase are among the best known. Peroxidase catalyzes a reaction involved in the inhibition of bacterial growth and metabolism, and the prevention of hydrogen peroxide accumulation, thus protecting proteins from the action of oxygen and reactive oxygen species (ROS). To better understand the role played by the oxidative stress in the aging process, we studied the relationship between total protein content, peroxidase activity, malondialdehyde (MDA) and nitric oxide (NO) content of human unstimulated whole saliva in 169 healthy subjects subdivided into groups according to age. Our results show a significant decrease in peroxidase activity with age. Moreover, the increase in saliva lipid peroxide levels indicates an enhanced free radical production that may contribute to tissue damage. On the other hand, findings concerning human unstimulated whole saliva NO content showed a significant increase in elderly subjects, suggesting that an enhanced NO production might depend on a stimulation of leukocyte-inducible NO synthase (i-NOS) activity. Our results suggest that during aging the oral tissues may become more susceptible to environmental factors due to a modification in the balance between different antimicrobial agents.

The aim of this study was to evaluate changes in the concentration of certain components of human unstimulated whole saliva during aging, in order to better understand the role played by aging in oral health. In particular, we studied total protein concentration, alpha-amylase activity, sialic acid content and calcium and phosphorus concentrations in 100 healthy subjects of both genders, aged between 10 and 80 years, who were subdivided into four groups according to their age: 10-25 years, 26-40 years, 41-65 years, and 66-80 years. Other than sialic acid, the concentrations of the components studied were not affected by age. There was a significant negative correlation between sialic acid content and age. Our data indicate the presence of a decreased submandibular/sublingual function with aging, thus suggesting the possibility of a concomitant reduction in the modulating action of unstimulated whole saliva on the oral flora.

Sialic acid (SA) content and Na+/K+-ATPase activity of red blood cell (RBC) membranes were studied in 26 normoalbuminuric patients with insulin-dependent diabetes mellitus (IDDM), 25 normoalbuminuric patients with non-insulin-dependent diabetes mellitus (NIDDM), and 40 healthy nondiabetic subjects with a negative family history for diabetes. A decrease in RBC membrane SA content and Na+/K+-ATPase activity was observed in older control subjects compared with younger controls. A significant correlation between age, Na+/K+-ATPase activity, and SA content was also found. No difference was observed in RBC membrane SA content between IDDM and NIDDM subjects, but Na+/K+-ATPase activity was significantly lower in IDDM patients. SA content was increased in NIDDM subjects compared with healthy subjects of similar age, whereas Na+/K+-ATPase activity was significantly lower in both IDDM and NIDDM subjects compared with controls. In NIDDM, Na+/K+-ATPase activity was significantly correlated with age, whereas both Na+/K+-ATPase activity and SA content were significantly correlated in IDDM and NIDDM patients. Hemoglobin A1c, (HbA1c) levels did not show any significant correlation either with Na+/K+-ATPase or with SA content in diabetic patients. The modified SA content and Na+/K+-ATPase activity in elderly subjects described in the present study indicate a similar behavior of the erythrocyte membrane during both RBC senescence and aging of subjects.