Effect of Antioxidants on the Fibroblast Replicative Lifespan In Vitro

Progress in the Development of Stem Cell-Derived Cell-Free Therapies for Skin Aging

Introduction

The skin is a vital organ as the body's largest barrier, but its function declines with aging. Therefore, research into effective regeneration treatments must continue to advance. Stem cell transplantation, a cell-based therapy, has become a popular skin-aging treatment, although it comes with drawbacks like host immune reactions. Stem cell-derived cell-free therapies have emerged as an alternative, backed by promising preclinical findings. Stem cell secretomes and extracellular vesicles (EVs) are the key components in cell-free therapy from stem cells. However, comprehensive reviews on the mechanisms of such treatments for skin aging are still limited.

Purpose

This review discusses stem cell-derived cell-free therapy's potential mechanisms of action related to skin aging prevention by identifying specific molecular targets suitable for the interventions.

Methods

A search identified 27 relevant in vitro studies on stem cell-derived cell-free therapy interventions in skin aging model cells without restricting publication years using PubMed, Scopus, and Google Scholar.

Results

Stem cell-derived cell-free therapy can prevent skin aging through various mechanisms, such as (1) involvement of multiple regenerative pathways [NFkb, AP-1, MAPK, P-AKT, NRF2, SIRT-1]; (2) oxidative stress regulation [by reducing oxidants (HO-1, NQO1) and enhancing antioxidants (SOD1, CAT, GP, FRAP)]; (3) preventing ECM degradation [by increasing elastin, collagen, HA, TIMP, and reducing MMP]; (4) regulating cell activity [by reducing cell senescence (SA-β-gal), apoptosis, and cell cycle arrest (P53, P12, P16); and enhancing autophagy, cell migration, and cell proliferation (Ki67)] (5) Regulating the inflammatory pathway [by reducing IL-6, IL-1, TNF-⍺, and increasing TGF-β]. Several clinical trials have also revealed improvements in wrinkles, elasticity, hydration, pores, and pigmentation.

Conclusion

Stem cell-derived cell-free therapy is a potential novel treatment for skin aging by cell rejuvenation through various molecular mechanisms.

Preventive Effect of Nuciferine on H2O2-Induced Fibroblast Senescence and Pro-Inflammatory Cytokine Gene Expression

Human dermal fibroblasts play an important role in skin homeostasis by producing and degrading extracellular matrix components. They have more replicative senescence when exposed to environmental and oxidative insults, resulting in human skin aging. However, this phenomenon can be mitigated by antioxidant phytochemicals. The aim of the present study was to investigate the potential of nuciferine (an alkaloid from Nelumbo nucifera leaf) in preventing stress-induced fibroblast senescence by using a hydrogen-peroxide (H₂O₂)-induced senescence model. We found that H₂O₂ treatment resulted in a significant increase in senescence-associated β-galactosidase (SA-β-gal)-positive cells. Nuciferine-treated cells, however, showed a reduction in senescent phenotype. Furthermore, we observed the key molecular markers including the senescence-associated secretory phenotype (SASP) and cell cycle regulators. The mRNA levels of CXCL1, CXCL2, IL-6, and IL-8 (pro-inflammatory cytokines) reduced significantly in nuciferine-treated cells. The extracellular IL-6 and IL-8 levels were also decreased in treated cells, whereas the key cell cycle regulators (p16 and p21) were markedly affected by nuciferine at the highest concentration. The results of the present study clearly show that the preventive activity of nuciferine against H₂O₂-induced senescence in dermal fibroblasts is fundamental and promising for further applications in anti-aging product research and development.

In Vitro Determination of the Skin Anti-Aging Potential of Four-Component Plant-Based Ingredient

The beauty industry is actively searching for solutions to prevent skin aging. Some of the crucial elements protecting cells from the aging process are telomere shortening, telomerase expression, cell senescence, and homeostasis of the redox system. Modification of these factors using natural antioxidants is an appealing way to support healthy skin aging. Therefore, in this study, we sought to investigate the antiaging efficacy of a specific combination of four botanical extracts (pomegranate, sweet orange, Cistanche and Centella asiatica) with proven antioxidant properties. To this end, normal human dermal fibroblasts were used as a cell model and the following studies were performed: cell proliferation was established by means of the MTT assay and the intracellular ROS levels in stress-induced premature senescence fibroblasts; telomere length measurement was performed under standard cell culture conditions using qPCR and under oxidative stress conditions using a variation of the Q-FISH technique; telomerase activity was examined by means of Q-TRAP; and AGE quantification was completed by means of ELISA assay in UV-irradiated fibroblasts. As a result, the botanical blend significantly reversed the H2O2-induced decrease in cell viability and reduced H2O2-induced ROS. Additionally, the presence of the botanical ingredient reduced the telomere shortening rate in both stressed and non-stressed replicating fibroblasts, and under oxidative stress conditions, the fibroblasts presented a higher median and 20th percentile telomere length, as well as a lower percentage of short telomeres (<3 Kbp) compared with untreated fibroblasts. Furthermore, the ingredient transiently increased relative telomerase activity after 24 h and prevented the accumulation of UVR-induced glycated species. The results support the potential use of this four-component plant-based ingredient as an antiaging agent.

We are all aging, and here's why

Here, through this review, we aim to serve this purpose by first discussing the statistics and aging demographics, including the life expectancy of the world and India, along with the gender life expectancy gap observed throughout the world, followed by explaining the hallmarks and integral causes of aging, along with the role played by senescent cells in controlling inflammation and the effect of senescence associated secretory phenotype on longevity. A few of the molecular pathways which are crucial in modulating the process of aging, such as the nutrient‐sensing mTOR pathway, insulin signaling, Nrf2, FOXO, PI3‐Akt, Sirtuins, and AMPK, and their effects are also covered in paramount detail. A diverse number of ingenious research methodologies are used in the modern era of longevity exploration. We have attempted to cover these methods under the umbrella of three broad categories: in vitro, in vivo, and in silico techniques. The drugs developed to attenuate the aging process, such as rapamycin, metformin, resveratrol, etc. and their interactions with the above‐mentioned molecular pathways along with their toxicity have also been reviewed in detail.

The Role of Antioxidants in the Interplay between Oxidative Stress and Senescence

Cellular senescence is an irreversible state of cell cycle arrest occurring in response to stressful stimuli, such as telomere attrition, DNA damage, reactive oxygen species, and oncogenic proteins. Although beneficial and protective in several physiological processes, an excessive senescent cell burden has been involved in various pathological conditions including aging, tissue dysfunction and chronic diseases. Oxidative stress (OS) can drive senescence due to a loss of balance between pro-oxidant stimuli and antioxidant defences. Therefore, the identification and characterization of antioxidant compounds capable of preventing or counteracting the senescent phenotype is of major interest. However, despite the considerable number of studies, a comprehensive overview of the main antioxidant molecules capable of counteracting OS-induced senescence is still lacking. Here, besides a brief description of the molecular mechanisms implicated in OS-mediated aging, we review and discuss the role of enzymes, mitochondria-targeting compounds, vitamins, carotenoids, organosulfur compounds, nitrogen non-protein molecules, minerals, flavonoids, and non-flavonoids as antioxidant compounds with an anti-aging potential, therefore offering insights into innovative lifespan-extending approaches.

The Feasibility of Utilizing Cultured Cordyceps militaris Residues in Cosmetics: Biological Activity Assessment of Their Crude Extracts

Solid-based residues (SBRs) left from harvesting the fruiting bodies of cultured Cordyceps mushrooms are a challenge to sustainability. Therefore, in this study, the SBRs from the cultivation of Cordyceps militaris (C. militaris) via solid-state fermentation (SSF) were employed to prepare crude extracts, with the aim of considering their possible use in cosmetics. The SBRs obtained from cultivation with solid media containing defatted rice bran mixed with barley, white rice, Riceberry rice, and wheat were named SBR-B, SBR-R, SBR-Rb, and SRB-W, respectively. They were extracted with solvents of differing polarity and then evaluated for their total phenolic content (TPC), total flavonoid content (TFC), and total carbohydrate content (TCC). In addition, antioxidant and tyrosinase inhibitory activities, photoprotection, and cytotoxicity were also assessed. The results revealed that the total bioactive contents and biological capacities of crude SBR extracts were significantly influenced by the types of SBR and extraction solvent (p < 0.05). The SBR-B extracted with hot water exhibited the highest antioxidant activity (66.62 ± 2.10, 212.00 ± 3.43, and 101.62 ± 4.42 mg TEAC/g extract) when assayed by DPPH, ABTS, and FRAP methods, respectively, whereas tyrosinase inhibitory activity (51.13 ± 1.11 mg KAE/g extract) with 90.43 ± 1.96% inhibition at 1 mg/mL was excellently achieved by SBR-Rb extracted by 50% (v/v) ethanol. Correlations between bioactive contents in the crude extracts and their biological activities were mostly proven at a strong level (p < 0.01). The capability of the crude extracts to absorb UV over the range of 290–330 nm disclosed their potential roles as natural UV absorbers and boosters. Cytotoxicity analysis using fibroblast cell lines tested with hot water and 50% (v/v) ethanolic SBR extracts demonstrated safe use within a concentration range of 0.001–10 mg/mL. Interestingly, their fibroblast proliferative capacity, indicating anti-aging properties, was highly promoted. The chemical composition analyzed via LC–MS/MS techniques showed that seven phenolic acids and four flavonoids were identified in the crude SBR extracts. Furthermore, the other compounds present included nucleosides, nucleobases, amino acids, sugars, phospholipids, alkaloids, organic acids, vitamins, and peptides. Therefore, it is emphasized that SBRs from C. militaris can be a prospective source for preparing crude extracts employed in cosmetics. Lastly, they could be further utilized as multifunctional ingredients in cosmetics and cosmeceuticals.

A Novel Biochemical Study of Anti-Dermal Fibroblast Replicative Senescence Potential of Panax Notoginseng Oligosaccharides

Dermal fibroblast replicative senescence that often occurs in aging skin is characterized by loss of cell proliferative capacity, cell cycle arrest, decreased cell elongation, and decreased synthesis of dermal extracellular matrix (ECM) components. Although Panax notoginseng is known for its effectiveness in alleviating many age-related degenerative diseases, few studies have evaluated P. notoginseng components for efficacy or mechanisms of action in delaying cell replicative senescence. In this study, P. notoginseng oligosaccharides (PNO) were isolated using a stepwise purification procedure involving water extraction and alcohol precipitation followed by DEAE Sepharose Fast Flow column chromatography, preparative high performance liquid chromatography, and size-exclusion chromatography. Monosaccharides detected in PNO constituents included mannose, galactose, and sorbitose in relative molar proportions of 14.2:12.3:1, respectively, aligning with PNO absorption spectrum results resembling typical known spectra for sugars. In vitro, PNO treatment of replicative senescent NIH-3T3 fibroblasts significantly promoted cell vitality, inhibited SA-β-galactosidase (SA-β-Gal) activity, and reduced p16 and p21 protein-level expression. Moreover, PNO treatment of senescent fibroblasts led to a lower proportion of G1 phase cells and higher proportion of S phase cells, while also inducing aging NIH-3T3 cells to migrate and synthesize collagen-I (CoL-I). Mechanistically, PNO treatment up-regulated expression of proliferating cell nuclear antigen (PCNA), cyclin E, cyclin D1, and cyclin-dependent kinase 4 (CDK4) proteins and promoted phosphorylation of MEK, p38, and ERK1/2 to trigger cell cycle progression. Additionally, PNO treatment also up-regulated protein-level expression of TGF-β1 and levels of p-Smad2/3, p-FAK, and p-Pax to trigger CoL-I synthesis and cell migration. Taken together, these findings demonstrate that oligosaccharides purified from P. notoginseng could reverse fibroblast replicative senescence by promoting fibroblast cell proliferation, migration, and CoL-I production.

4′,7-Isoflavandiol (Equol) Enhances Human Dermal Fibroblast Renewal and Has Effects Similar to 17β-Estradiol in Stimulating Collagen and Elastin Expression. Cell Cycle and RT-PCR Analysis without Phenol Red

Polyphenols have general health benefits including anti-photoaging influences to counter the negative effects of ultra-violet (UV) rays from solar light (via the generation of reactive oxygen species (ROS) and oxidative stress (OS)), which leads to the stimulation of matrix metalloproteinases (MMPs) that break down collagen and elastin. The changes in elastin and collagen represent major factors in dermal aging along with a decrease in skin fibroblast number and function. The purpose of this study was to determine the influence of a polyphenolic molecule, 4′,7-Isoflavandiol (Equol) at 10 nM on: (1) fibroblast number and function via cell cycle testing (including apoptosis) and collagen protein expression (types I and III) using long-term (eight-week) 3D human fibroblast cultures by intracellular fluorescent-activated cell sorting (FACS) analysis, and (2) quantifying elastin gene expression levels in short-term (four day) cultures using human monolayer fibroblasts by RT-PCR. In both in vitro testing methods, the presence of phenol red (tissue culture indicator) interfered with the parameter results. Therefore, all experiments were performed without phenol red. Using FACS analysis in the long-term 3D cultures exposure to 10 nM of equol for four days significantly increased the percentage of cycling fibroblasts (rejuvenation) above vehicle control (dimethyl sulfoxide (DMSO)) or 17β-estradiol levels, while apoptosis was not altered by any treatment. In addition, in the long-term cultures, collagen levels were significantly increased in the equol and 17β-estradiol treatments above vehicle control values. In short-term cultures, 10 nM of equol or 17β-estradiol significantly increased elastin gene expression levels above vehicle control values. In summary: (a) phenol red may interfere with tissue culture parameter results and (b) the polyphenolic equol compound, derived from plants, may provide protection against photoaging in cosmetic formulations by stimulating collagen, elastin, and enhancing fibroblast renewal.