Melanoblasts, the precursors to melanocytes, originate in the neural crest. Some melanoblasts can travel to the hair follicle and further differentiate into pigment melanin-producing melanocytes. Hair follicles contain a pool of undifferentiated melanocyte stem cells (MSCs), which are sources of differentiated melanocytes, and functional melanocytes exhist in the hair bulb. The volume, life, and activity of melanocytes in a hair follicle is closely related with the growth cycle of follicle. Appearance of gray hair gray results from incomplete MSCs maintenance.
Aging ; physiology ; Cell Differentiation ; Hair Follicle ; cytology ; physiology ; Humans ; Melanocytes ; physiology ; Stem Cells ; physiology

Bone marrow harvested by aspiration contains connective tissue progenitor cells which can be selectively isolated and induced to express bone phenotype in vitro. The osteoblastic progenitor can be estimated by counting the number of cells attach using the haemacytometer. This study was undertaken to test the hypothesis that human aging is associated with a significant change on the number of osteoblastic progenitors in the bone marrow. Bone marrow aspirates were harvested from 38 patients, 14 men (age 11-70) and 24 women (age 10-70) and cultured in F12: DMEM (1:1). In total 15 bone marrow samples have been isolated from patients above 40 years old (men/women) of age. Fourteen (93.3%) of this samples failed to proliferate. Only one (6.7%) bone marrow sample from a male patient, aged 59 years old was successfully cultured. Seventy percent (16/23) of the samples from patient below than 40 years old were successfully cultured. However, our observation on the survival rate for cells of different gender from patient below 40 years old does not indicate any significant difference. From this study, we conclude that the growth of bone marrow stromal cells possibly for bone engineering is better from bone marrow aspirates of younger patient.
Age Factors ; Bone Marrow Cells/*cytology ; Cell Aging/*physiology ; Cell Division/*physiology ; Cell Survival/physiology ; Mesenchymal Stem Cells/*cytology ; Osteoblasts/*cytology ; Sex Factors ; Stromal Cells/cytology ; *Tissue Engineering

Chronological aging is the leading risk factor for human diseases, while aging at the cellular level, namely cellular senescence, is the fundamental driving force of organismal aging. The impact of cellular senescence on various life processes, including normal physiology, organismal aging and the progress of various age-related pathologies, has been largely ignored for a long time. However, with recent advancement in relevant fields, cellular senescence has become the core of aging biology and geriatric medicine. Although senescent cells play important roles in physiological processes including tissue repair, wound healing, and embryonic development, they can also contribute to tissue dysfunction, organ degeneration and various pathological conditions during adulthood. Senescent cells exert paracrine effects on neighboring cells in tissue microenvironments by developing a senescence-associated secretory phenotype, thus maintaining long-term and active intercellular communications that ultimately results in multiple pathophysiological effects. This is regarded as one of the most important discoveries in life science of this century. Notably, selective elimination of senescent cells through inducing their apoptosis or specifically inhibiting the senescence-associated secretory phenotype has shown remarkable potential in preclinical and clinical interventions of aging and age-related diseases. This reinforces the belief that senescent cells are the key drug target to alleviate various aging syndromes. However, senescent cells exhibit heterogeneity in terms of form, function and tissue distribution, and even differ among species, which presents a challenge for the translation of significant research achievements to clinical practice in future. This article reviews and discusses the characteristics of senescent cells, current targeting strategies and future trends, providing useful and valuable references for the rapidly blooming aging biology and geriatric medicine.
Humans ; Adult ; Aged ; Cellular Senescence/genetics* ; Aging ; Apoptosis ; Cell Communication ; Wound Healing/physiology*

Estimating tooth age and skeletal age are the two primary methods in age estimation of forensic medicine. But they are often impacted with geographical environment, nutrition, habitation and ethenologic differences, so the accuracy will be reduced, especially to the adult. With the study of telomere, it is certain that the length of the telomere DNA can reflect the cell division and represent the cell lifespan, and it has some pertinence to the age of the donor, so to measure the length of telomere DNA is a new and valuable method for age estimation in the forensic medicine.
Adolescent ; Adult ; Aging/physiology* ; Blotting, Southern/methods* ; Cell Division/physiology* ; DNA/analysis* ; Forensic Medicine/methods* ; Humans ; Polymorphism, Restriction Fragment Length ; Telomere/physiology*

Skin is the largest organ in human system and plays a vital role as a barrier against environment and pathogens. Skin regeneration is important in tissue engineering especially in cases of chronic wounds. With the tissue engineering technology, these skins equivalent have been use clinically to repair burns and wounds. Consented redundant skin samples were obtained from patients aged 9 to 65 years old. Skin samples were digested with dispase, thus separating the epidermis and the dermis layer. The epidermis layer was trypsinized and cultured in DKSFM in 6-well plate at 37 degrees C and 5% CO2. Once confluent, the culture were trypsinized and the cells were pooled. Cells were counted using haemacytometer. Doubling time and viability were calculated and analysed. From the result, we conclude that doubling time and viability of in vitro keratinocytes cultured in DKSFM media is not age dependant.
Age Factors ; Burns/physiopathology ; Burns/*therapy ; Cell Aging/*physiology ; Cell Division/physiology ; Cell Survival/physiology ; Chronic Disease ; Keratinocytes/*cytology ; *Skin Transplantation ; Statistics ; Tissue Engineering/*methods ; Wound Healing/physiology ; Wounds and Injuries/physiopathology ; Wounds and Injuries/*therapy

Telomeres serve a critical role in maintenance of genomic stability in all eukaryotes, from yeast to human. The maintenance of telomeres is achieved by the telomerase complex, which is largely composed of telomerase reverse transcriptase (TERT) and telomerase RNA component (TERC). A variety of mouse models have provided valuable insights into the relationship between the telomerase complex and telomere dysfunction at the organismal level and helped understand their biological significance in human. Recently, in addition to its role in maintenance of the telomeres, novel functions of the telomerase complex have been emerging. In this review, studies of all gene-targeted or transgenic mouse models so far generated for telomerase and telomere biology are comprehensively described, and potential novel functions of telomerase are briefly discussed
Animals ; Cell Aging/*physiology ; Mice ; Mice, Knockout ; Mice, Transgenic ; Models, Animal ; RNA/*metabolism ; Telomerase/*metabolism ; Telomere/*metabolism

To determine the role of placenta cells allogeneic graft in mammalian longevity, the 15-month-old female BALB/c mice (n = 50) were divided into Control group (A), Short-term transplanted group (B) and Long-term transplanted many times group (C). Their placentae (at 18 days of gestation) were taken out and ground with 50-eye cell grit, and the cells were intraperitoneally injected into the mice of B group and C group three times at intervals of 10 days; then the cells were transplanted into the mice of C group many times till the time of death. The mice were evaluated by use of ultrasound-cardiogram; autopsy; score of cardia, spleen, skin, lung, kidney; histopathology; serum total superoxide dismutase activity, serum maleic dialdehyde content, and serum glutathione peroxidase activity. The long-term surviving stem cells were found to be located in many organ tissues of B and C groups' mice with in situ Y chromosomal hybridization dyeing. Median life span of B group mice was 1.7 times that of A group's after transplantation, but there was no statistically significant difference between B group and C group. Three months after transplantation, in B group, the pathological developments of significant skin, cardia, lung, and kidney were delayed; the retrogradation of heart function was attenuated; the data on heart mass index (mass of heart/mass of body), left ventricular mass and serum Maleic Dialdehyde content, and on spleen mass index (mass of spleen/mass of body), left ventricular diastolic volume, serum Total Superoxide Dismutase activity and serum Glutathione Peroxidase activity, were all in a direction favourable to B group (P < 0.05). These results were in line with the hypothesis, i. e. longevity can be enhanced to some extent by transplantation of placenta cells.
Aging ; physiology ; Animals ; Cell Transplantation ; methods ; Female ; Mice ; Mice, Inbred BALB C ; Placenta ; cytology ; Pregnancy ; Random Allocation

Aging of craniofacial skeleton significantly impairs the repair and regeneration of trauma-induced bony defects, and complicates dental treatment outcomes. Age-related alveolar bone loss could be attributed to decreased progenitor pool through senescence, imbalance in bone metabolism and bone-fat ratio. Mesenchymal stem cells isolated from oral bones (OMSCs) have distinct lineage propensities and characteristics compared to MSCs from long bones, and are more suited for craniofacial regeneration. However, the effect of epigenetic modifications regulating OMSC differentiation and senescence in aging has not yet been investigated. In this study, we found that the histone demethylase KDM4B plays an essential role in regulating the osteogenesis of OMSCs and oral bone aging. Loss of KDM4B in OMSCs leads to inhibition of osteogenesis. Moreover, KDM4B loss promoted adipogenesis and OMSC senescence which further impairs bone-fat balance in the mandible. Together, our data suggest that KDM4B may underpin the molecular mechanisms of OMSC fate determination and alveolar bone homeostasis in skeletal aging, and present as a promising therapeutic target for addressing craniofacial skeletal defects associated with age-related deteriorations.
Aging ; Cell Differentiation ; Facial Bones/physiology* ; Humans ; Jumonji Domain-Containing Histone Demethylases/genetics* ; Mesenchymal Stem Cells/cytology* ; Osteogenesis ; Osteoporosis

To determine the role of allogeneil graft of mesenchymal stem cells in mammalian longevity, mesenchymal stem cells were isolated from BALB/c mouse uterine-incision delivery fetus by two successive density gradient centrifugations, and then were purified and amplified by adherent culture. Identified P1 mesenchymal stem cells were injected (i.v.) through vena caudalis into the 15-month-old female BALB/c mice three times. The mice were evaluated with ultrasoundcardiogram, autopsy, score of cardiac, skin, lung, kidney, colon histopathology and serum total superoxide dismutase activity, maleic dialdehyde content, glutathione peroxidase activity. The results showed that after transplantation, the long-term surviving stem cells were found to be located in many organ tissues with in situ Y chromosomal hybridization dyeing. Median life span was increased in these animals after transplantation. Skin, cardiac, lung, kidney and colon pathology development were delayed. The retrogradation of heart function was attenuated, the increase of heart mass index (the mass of heart/the mass of the body), and serum maleic dialdehyde content, the decrease of spleen mass index (the mass of spleen/the mass of the body), serum total superoxide dismutase activity and glutathione peroxidase activity were reduced three months after transplantation (all P<0.05). These results support the idea that longevity can be enhanced by transplantation of mesenchymal stem cells and reinforce the hypothesis of mesenchymal stem cell as antiager.
Aging ; physiology ; Animals ; Female ; Fetal Stem Cells ; transplantation ; Longevity ; physiology ; Mesenchymal Stem Cell Transplantation ; Mice ; Mice, Inbred BALB C ; Random Allocation

The gradual loss of telomeric DNA can contribute to replicative senescence and thus, having longer telomeric DNA is generally considered to provide a longer lifespan. Maintenance and stabilization of telomeric DNA is assisted by binding of multiple DNA-binding proteins, including those involved in double strand break (DSB) repair. We reasoned that declining DSB repair capacity and increased telomere shortening in aged individuals may be associated with decreased expression of DSB repair proteins capable of telomere binding. Our data presented here show that among the DSB repair proteins tested, only the expression of Ku70 and Mre11 showed statistically significant age-dependent changes in human lymphocytes. Furthermore, we found that expressions of Ku70 and Mre11 are statistically correlated, which indicate that the function of Ku70 and Mre11 may be related. All the other DSB repair proteins tested, Sir2, TRF1 and Ku80, did not show any significant differences upon aging. In line with these data, people who live in the regional community (longevity group), which was found to have statistically longer average life span than the rest area, shows higher level of Ku70 expression than those living in the neighboring control community. Taken together, our data show, for the first time, that Ku70 and Mre11 may represent new biomarkers for aging and further suggest that maintenance of higher expression of Ku70 and Mre11 may be responsible for keeping longer life span observed in the longevity group.
Telomere/genetics ; Middle Aged ; Longevity ; Humans ; DNA-Binding Proteins/*metabolism ; DNA Repair/*genetics ; DNA/genetics ; Cell Aging/*physiology ; CD4-Positive T-Lymphocytes/metabolism ; Antigens, Nuclear/*metabolism ; Aging/*physiology ; Aged, 80 and over ; Aged ; Adult