periodontal ligament stem cells; aging; proliferation; osteogenic differentiation Objective The aim of this study is to investigate the proliferation, differentiation and apoptosis of periodontal ligament stem cells...periodontal ligament stem cells; aging; proliferation; osteogenic differentiation Objective The aim of this study is to investigate the proliferation, differentiation and apoptosis of periodontal ligament stem cells （PDLSC） derived from different aged donors, and to evaluate the effects of aging on the biological characteristics of PDLSC. Methods Periodontal ligament tissues were obtained from 24 surgically extracted human premolars during orthodontics therapy. The specimens were divided into three groups according to the donor’s age. Group A： 18-20 years, group B： 30-35 years, group C： 45-50 years. PDLSC were isolated and cultured using a tissue-block-based enzymolytic method by limiting dilution assay. The colony forming efficiency of PDLSC for three experimental groups was determined. Senescence-Associated β-Galactosidase （SA-β-G） expression in the three groups was examined using β-galactosidase staining working solution. Cell cycle and apoptosis of the PDLSC were examined by the flow cytometry. Alkaline phosphatase （ALP） activity was evaluated by ALP staining. The expression of osteoplastic differentiation related genes Runt-related transcription factor-2 （Runx-2）, Collagen Type 1 （col-1）, and ALP of PDLSC were examined by quantitative real-time RT-PCR. Results The colony forming efficiency of PDLSC in Group A, B and C was 36.67%, 22.67% and 9.33%, respectively, which decreased with donors’ age （P〈0.05）. SA-β-G expression of the senescent PDLSC in group A, B and C were 4.14%, 16.39%, 50.38%, respectively （P〈0.05）. Cells in G2/S phase was 38.73%, 29.88%, 18.25% （P〈0.05）, and the apoptosis rate was 1.57%, 4.56%, 5.84% （P〈0.05）, in group A, B and C respectively. The ALP staining in the three groups decreased with the increase of donors’ ages, and the expression of Runx-2, col-1 and ALP decreased gradually from group A to group C （all P〈0.05）, which indicated the osteogenic differentiation capacity of PDLSC decreased while donor aging. Conclusion Human PDLSC could be successfully isolated from periodontal ligament tissues of different aged donors. However, the proliferation and osteogenic differentiation capacity of PDLSC decreased while donor aging.展开更多
Cognitive impairment is a consequence of the normal aging process that effects many species, including humans and rodent models. Decline in hippocampal memory function is especially prominent with age and often reduce...Cognitive impairment is a consequence of the normal aging process that effects many species, including humans and rodent models. Decline in hippocampal memory function is especially prominent with age and often reduces quality of life. As the aging population expands, the need for interventional strategies to prevent cognitive decline has become more pressing. Fortunately, several major lifestyle factors have proven effective at combating hippocampal aging, the most well-known of which are environmental enrichment and exercise. While the evidence supporting the beneficial nature of these factors is substantial, a less well-understood factor may also contribute to healthy cognitive aging: social engagement. We review the evidence supporting the role of social engagement in preserving hippocampal function in old age. In elderly humans, high levels of social engagement correlate with better hippocampal function, yet there is a dearth of work to indicate a causative role. Existing rodent literature is also limited but has begun to provide causative evidence and establish candidate mechanisms. Summed together, while many unanswered questions remain, it is clear that social engagement is a viable lifestyle factor for preserving cognitive function in old age. Social integration across the lifespan warrants more investigation and more appreciation when designing living circumstances for the elderly.展开更多
基金Supported by National Natural Science Foundation of China（51473175）, Science and Technology Nova Plan of Beijing City（Z141107001814101）.
文摘periodontal ligament stem cells; aging; proliferation; osteogenic differentiation Objective The aim of this study is to investigate the proliferation, differentiation and apoptosis of periodontal ligament stem cells （PDLSC） derived from different aged donors, and to evaluate the effects of aging on the biological characteristics of PDLSC. Methods Periodontal ligament tissues were obtained from 24 surgically extracted human premolars during orthodontics therapy. The specimens were divided into three groups according to the donor’s age. Group A： 18-20 years, group B： 30-35 years, group C： 45-50 years. PDLSC were isolated and cultured using a tissue-block-based enzymolytic method by limiting dilution assay. The colony forming efficiency of PDLSC for three experimental groups was determined. Senescence-Associated β-Galactosidase （SA-β-G） expression in the three groups was examined using β-galactosidase staining working solution. Cell cycle and apoptosis of the PDLSC were examined by the flow cytometry. Alkaline phosphatase （ALP） activity was evaluated by ALP staining. The expression of osteoplastic differentiation related genes Runt-related transcription factor-2 （Runx-2）, Collagen Type 1 （col-1）, and ALP of PDLSC were examined by quantitative real-time RT-PCR. Results The colony forming efficiency of PDLSC in Group A, B and C was 36.67%, 22.67% and 9.33%, respectively, which decreased with donors’ age （P〈0.05）. SA-β-G expression of the senescent PDLSC in group A, B and C were 4.14%, 16.39%, 50.38%, respectively （P〈0.05）. Cells in G2/S phase was 38.73%, 29.88%, 18.25% （P〈0.05）, and the apoptosis rate was 1.57%, 4.56%, 5.84% （P〈0.05）, in group A, B and C respectively. The ALP staining in the three groups decreased with the increase of donors’ ages, and the expression of Runx-2, col-1 and ALP decreased gradually from group A to group C （all P〈0.05）, which indicated the osteogenic differentiation capacity of PDLSC decreased while donor aging. Conclusion Human PDLSC could be successfully isolated from periodontal ligament tissues of different aged donors. However, the proliferation and osteogenic differentiation capacity of PDLSC decreased while donor aging.
基金partially supported by a R00 Pathway to Independence Award from NIH/NINDS(R00NS089938)(to EDK)
文摘Cognitive impairment is a consequence of the normal aging process that effects many species, including humans and rodent models. Decline in hippocampal memory function is especially prominent with age and often reduces quality of life. As the aging population expands, the need for interventional strategies to prevent cognitive decline has become more pressing. Fortunately, several major lifestyle factors have proven effective at combating hippocampal aging, the most well-known of which are environmental enrichment and exercise. While the evidence supporting the beneficial nature of these factors is substantial, a less well-understood factor may also contribute to healthy cognitive aging: social engagement. We review the evidence supporting the role of social engagement in preserving hippocampal function in old age. In elderly humans, high levels of social engagement correlate with better hippocampal function, yet there is a dearth of work to indicate a causative role. Existing rodent literature is also limited but has begun to provide causative evidence and establish candidate mechanisms. Summed together, while many unanswered questions remain, it is clear that social engagement is a viable lifestyle factor for preserving cognitive function in old age. Social integration across the lifespan warrants more investigation and more appreciation when designing living circumstances for the elderly.
