Development of personalized skin treatment in medicine and skin care may benefit from simple and accurate evaluation of the fraction of senescent skin fibroblasts that lost their proliferative capacity. We examined whether enriched analysis of colonies formed by primary human skin fibroblasts, a simple and widely available cellular assay, could reveal correlations with the fraction of senescent cells in heterogenic cell population. We measured fractions of senescence associated β-galactosidase (SA-βgal) positive cells in either mass cultures or colonies of various morphological types (dense, mixed and diffuse) formed by skin fibroblasts from 10 human donors. Although the donors were chosen to be within the same age group (33-54 years), the colony forming efficiency of their fibroblasts (ECO-f) and the percentage of dense, mixed and diffuse colonies varied greatly among the donors. We showed, for the first time, that the SA-βgal positive fraction was the largest in diffuse colonies, confirming that they originated from cells with the least proliferative capacity. The percentage of diffuse colonies was also found to correlate with the SA-βgal positive cells in mass culture. Using Ki67 as a cell proliferation marker, we further demonstrated a strong inverse correlation (r=−0.85, p=0.02) between the percentage of diffuse colonies and the fraction of Ki67+ cells. Moreover, a significant inverse correlation (r=−0.94, p=0.0001) between the percentage of diffuse colonies and ECO-f was found. Our data indicate that quantification of a fraction of diffuse colonies may provide a simple and useful method to evaluate the extent of cellular senescence in human skin fibroblasts.

Biocompatible ceramic fillers are capable of sustaining bone formation in the proper environment. The major drawback of these scaffolding materials is the absence of osteoinductivity. To overcome this limitation, bioengineered scaffolds combine osteoconductive components (biomaterials) with osteogenic features such as cells and growth factors. The bone marrow mesenchymal stromal cells (BMMSCs) and the β-tricalcium phosphate (β-TCP) are well-known and characterized in this regard. The present study was conducted to compare the properties of novel octacalcium phosphate ceramic (OCP) granules with β-TCP (Cerasorb(®)), gingiva-derived mesenchymal stromal cells (GMSCs) properties with the BMMSCs and osteogenic and angiogenic properties of a bioengineered composite based on OCP granules and the GMSCs. This study demonstrates that GMSCs and BMMSСs have a similar osteogenic capacity. The usage of OCP ceramic granules in combination with BMMSCs/GMSCs significantly affects the osteo- and angiogenesis in bone grafts of ectopic models.

Skin aging is a multi-factorial process that affects nearly every aspect of skin biology and function. The processes developing in the skin during aging are based on fundamental molecular mechanisms associated with fibroblasts, the main cellular population of the dermis. It has been revealed that the amount of fibroblasts decreases markedly with age and their functional activity is also reduced. This inevitably leads to a decrease in the regenerative abilities of the skin and the progression of its aging. In this review we consider the mechanisms underlying these processes, mainly the changes observed with age in the stem/progenitor cells that constitute the fibroblastic differon of the dermis and form their microenvironment (niches). These changes lead to the depletion of stem cells, which, in turn, leads to a decrease in the number of differentiated (mature) dermal fibroblasts responsible for the production of the dermal extracellular matrix and its remodeling. We also describe in detail DNA damages, their cellular and systemic consequences, molecular mechanisms of DNA damage response, and also the role of fibroblast senescence in skin aging.

We assessed the effects of donor age on clonogenicity, proliferative potential, and spontaneous γH2AX foci in the proliferating (Ki67 +) and senescent (SA β-gal +) cultures of skin fibroblasts isolated from 34 donors of different age (23-82 years). Here, we demonstrated that neither the colony forming effectiveness of proliferating (Ki67+) fraction of the fibroblasts nor the average number of γH2AX foci of the same fraction does not depend on the age of the donor. The correlation between the number of γH2AX foci and the donor’s age was reliable in quiescent (Ki67-) cells. The average number of γH2AX foci in quiescent fibroblasts of donors older than 68 years was about two times higher than in the same cells of up to 30 years old donors. The number of γH2AX foci demonstrated a statistically significant positive correlation with the fraction of proliferating cells in fibroblast cultures. On average, proliferating cells have twice as many the γH2AX foci in comparison with the quiescent cells. Within a population of proliferating (Ki67+) cells, the degree of senescence correlated with a relative declining of constitutive γH2AX foci number, whereas in the population of quiescent (Ki67-) cells, it was proportional to augmenting the number of the γH2AX foci. Our data on a statistically significant (p=0.001) correlation between the age of the donor and the number of constitutive γH2AX foci in quiescent cells, could point out the ongoing DNA-damage response due in the maintenance of the senescent state of cells.

Difficulties related to the obtainment of stem/progenitor cells from skeletal muscle tissue make the search for new sources of myogenic cells highly relevant. Alveolar mucosa might be considered as a perspective candidate due to availability and high proliferative capacity of its cells. Human alveolar mucosa cells (AMC) were obtained from gingival biopsy samples collected from 10 healthy donors and cultured up to 10 passages. AMC matched the generally accepted multipotent mesenchymal stromal cells criteria and possess population doubling time, caryotype and immunophenotype stability during long-term cultivation. The single myogenic induction of primary cell cultures resulted in differentiation of AMC into multinucleated myotubes. The myogenic differentiation was associated with expression of skeletal muscle markers: skeletal myosin, skeletal actin, myogenin and MyoD1. Efficiency of myogenic differentiation in AMC cultures was similar to that in skeletal muscle cells. Furthermore, some of differentiated myotubes exhibited contractions in vitro. Our data confirms the sufficiently high myogenic potential and proliferative capacity of AMC and their ability to maintain in vitro proliferation-competent myogenic precursor cells regardless of the passage number.

Basic molecular mechanisms, associated with the main cell population of the dermis - fibroblasts - are the basis of skin aging. The number of functionally active fibroblasts in the skin and their biosynthetic activity decreases with age, thus enhancement of their cell density with synthetically active cells is accepted as a one of the most effective methods. The objective of the present study was to evaluate the safety and effectiveness of intradermal administration of autologous dermal fibroblasts in a year after treatment of 17 patients, aged 45-65 years. Results obtained with modern instrumental skin diagnostic methods (vacuum cutometry, optical profilometry, VISIA photometric analysis, etc.) demonstrate the safety and clinical effectiveness of dermal autofibroblast therapy: after transplantation, cultured autofibroblasts keep their biosynthetic activity and produce extracellular matrix for at least 12 months. As a result, remodelling of the dermis microstructures is observed, accompanied by a progressive increase of collagen content and thickness of the dermis (up to 62.5 ±6.7% in 12 months). This is clinically expressed by increase of skin elasticity (24.0 ±4.3% in periorbital area) and thickness of the skin, and by decrease in the number and depth of wrinkles (46 ±7% by the end of observation period). Copyright © 2014 John Wiley & Sons, Ltd.

Skin aging is a multi-factorial process that affects nearly every aspect of skin biology and function. With age, an impairment of structures, quality characteristics, and functions of the dermal extracellular matrix (ECM) occurs in the skin, which leads to disrupted functioning of dermal fibroblasts (DFs), the main cells supporting morphofunctional organization of the skin. The DF functioning directly depends on the state of the surrounding collagen matrix (CM). The intact collagen matrix ensures proper adhesion and mechanical tension in DFs, which allows these cells to maintain collagen homeostasis while ECM correctly regulates cellular processes. When the integrity of CM is destroyed, mechanotransduction is disrupted, which is accompanied by impairment of DF functioning and destruction of collagen homeostasis, thereby contributing to the progression of aging processes in skin tissues. This article considers in detail the processes of skin aging and associated changes in the skin layers, as well as the mechanisms of these processes at the molecular level.

No abstract