Potential of Naturally Derived Compounds in Telomerase and Telomere Modulation in Skin Senescence and Aging

Quercetin Intake and Absolute Telomere Length in Patients with Type 2 Diabetes Mellitus: Novel Findings from a Randomized Controlled Before-and-After Study

Telomeres, the protective chromosomal ends, progressively shorten and potentially are implicated in the pathogenesis of age-related diseases. In type 2 diabetes (T2DM), telomere shortening may play an important role, but the whole 'picture' remains limited. From a therapeutic perspective, the phytonutrient quercetin appears to be clinically effective and safe for patients with T2DM. Considering the above, we aimed to examine whether quercetin could interfere with telomere length (TL) dynamics. One hundred patients with T2DM on non-insulin medications registered within a primary healthcare facility were stratified by age and sex and randomly assigned to either standard care or standard care plus quercetin (500 mg/day) for 12 weeks, succeeded by an 8-week washout period and another 12 weeks of supplementation. Of the 88 patients completing the trial, 82 consented to blood sampling for TL measurements. Health assessments and whole blood absolute TL measurements using quantitative polymerase chain reaction (qPCR) were conducted at baseline and study end, and the findings of this subcohort are presented. Quercetin supplementation was associated with a significant increase in mean TL (odds ratio ≥ 2.44; p < 0.05) with a strengthened association after full adjustment for potential confounders through multiple logistic regression analysis (odds ratio = 3.48; p = 0.026), suggesting it as a potentially promising supplementation option. Further studies are needed to confirm this finding, elucidating the underlying molecular mechanisms of quercetin.

Exploring the Geroprotective Potential of Nutraceuticals

Aging is the result of the accumulation of a wide variety of molecular and cellular damages over time, meaning that "the more damage we accumulate, the higher the possibility to develop age-related diseases". Therefore, to reduce the incidence of such diseases and improve human health, it becomes important to find ways to combat such damage. In this sense, geroprotectors have been suggested as molecules that could slow down or prevent age-related diseases. On the other hand, nutraceuticals are another set of compounds that align with the need to prevent diseases and promote health since they are biologically active molecules (occurring naturally in food) that, apart from having a nutritional role, have preventive properties, such as antioxidant, anti-inflammatory and antitumoral, just to mention a few. Therefore, in the present review using the specialized databases Scopus and PubMed we collected information from articles published from 2010 to 2023 in order to describe the role of nutraceuticals during the aging process and, given their role in targeting the hallmarks of aging, we suggest that they are potential geroprotectors that could be consumed as part of our regular diet or administered additionally as nutritional supplements.

Anti-Aging Effects of Flavonoids from Plant Extracts

Aging is a natural and irreversible process, affecting living organisms by negatively impacting the tissues' and cells' morphology and functionality and consequently being responsible for aging-related diseases. Taking into account the actual preoccupations of both consumers and researchers, healthy anti-aging alternatives are being intensively studied in order to address such concerns. Due to their functional features, plant flavonoids can be considered valuable nutraceuticals. This paper highlights the possibilities to use flavonoids extracted from various plants for their anti-aging potential on the skin, brain, and heart. Moreover, their anticarcinogenic, anti-inflammatory, and anti-diabetic properties are summarized, along with the senescence-associated mechanisms. Both the nutraceutical and cosmeceutical fields are continuously developing and flavonoids originating from plants are promising candidates to obtain such products. Thus, the bioactive compounds' extraction and their subsequent involvement in innovative product manufacturing must be carefully performed while being aware of the various intrinsic and extrinsic factors that may affect the phytochemicals' structures, bioavailability, and health effects.

A novel nutraceutical formulation increases telomere length and activates telomerase activity in middle‑aged rats

Telomeres are major contributors to cell fate and aging through their involvement in cell cycle arrest and senescence. The accelerated attrition of telomeres is associated with aging‑related diseases, and agents able to maintain telomere length (TL) through telomerase activation may serve as potential treatment strategies. The aim of the present study was to assess the potency of a novel telomerase activator on TL and telomerase activity in vivo. The administration of a nutraceutical formulation containing Centella asiatica extract, vitamin C, zinc and vitamin D3 in 18‑month‑old rats for a period of 3 months reduced the telomere shortening rate at the lower supplement dose and increased mean the TL at the higher dose, compared to pre‑treatment levels. TL was determined using the Q‑FISH method in peripheral blood mononuclear cells collected from the tail vein of the rats and cultured with RPMI‑1640 medium. In both cases, TLs were significantly longer compared to the untreated controls (P≤0.001). In addition, telomerase activity was increased in the peripheral blood mononuclear cells of both treatment groups. On the whole, the present study demonstrates that the nutraceutical formulation can maintain or even increase TL and telomerase activity in middle‑aged rats, indicating a potential role of this formula in the prevention and treatment of aging‑related diseases.

Hallmarks of Skin Aging: Update

Aging is defined as impaired physiological integrity, decreased function, increased susceptibility to external risk factors and various diseases. Skin, the largest organ in our body, may become more vulnerable to insult as time goes by and behave as aged skin. Here, we systemically reviewed three categories including seven hallmarks of skin aging. These hallmarks including genomic instability and telomere attrition, epigenetic alterations and loss of proteostasis, deregulated nutrient-sensing, mitochondrial damage and dysfunction, cellular senescence, stem cell exhaustion/dysregulation, and altered intercellular communication. These seven hallmarks can generally be divided into three categories including (i) causes of damages as primary hallmarks in skin aging; (ii) responses to damage as antagonistic hallmarks in skin aging; and (iii) culprits of the phenotype as integrative hallmarks in skin aging.

Fisetin alleviates cellular senescence through PTEN mediated inhibition of PKCδ-NOX1 pathway in vascular smooth muscle cells

Reactive oxygen species (ROS) are a key risk factor of cellular senescence and age-related diseases, and protein kinase C (PKC) has been shown to activate NADPH oxidases (NOXs), which generate ROS. Although PKC activation induces oxidative stress, leading to the cellular dysfunction in various cell types, the correlation between PKC and senescence has not been reported in vascular smooth muscle cell (VSMC). Several studies have indicated cellular senescence is accompanied by phosphatase and tensin homolog (PTEN) loss and that an interaction exists between PTEN and PKC. Therefore, we aimed to determine whether PTEN and PKC are associated with VSMC senescence and to investigate the mechanism involved. We found hydrogen peroxide (H₂O₂) decreased PTEN expression and increased PKCδ phosphorylation. Moreover, H₂O₂ upregulated the NOX1 subunits, p22^phox and p47^phox, and induced VSMC senescence via p53-p21 signaling pathway. We identified PKCδ activation contributed to VSMC senescence through activation of NOX1 and ROS production. However, fisetin inhibited cellular senescence induced by the PTEN-PKCδ-NOX1-ROS signaling pathway, and this anti-aging effect was attributed to reduced ROS production caused by suppressing NOX1 activation. These results suggest that the PTEN-PCKδ signaling pathway is directly related to senescence via NOX1 activation and that the downregulation of PKCδ by flavonoids provides a potential means of treating age-associated diseases.

Potent telomerase activators from a novel sapogenin via biotransformation utilizing Camarosporium laburnicola, an endophytic fungus

BACKGROUND

Cycloartane-type triterpenoids possess important biological activities, including immunostimulant, wound healing, and telomerase activation. Biotransformation is one of the derivatization strategies of natural products to improve their bioactivities. Endophytic fungi have attracted attention in biotransformation studies because of their ability to perform modifications in complex structures with a high degree of stereospecificity.

RESULTS

This study focuses on biotransformation studies on cyclocephagenol (1), a novel cycloartane-type sapogenin from Astragalus species, and its 12-hydroxy derivatives (2 and 3) to obtain new telomerase activators. Since the hTERT protein levels of cyclocephagenol (1) and its 12-hydroxy derivatives (2 and 3) on HEKn cells were found to be notable, biotransformation studies were carried out on cyclocephagenol and its 12-hydroxy derivatives using Camarosporium laburnicola, an endophytic fungus isolated from Astragalus angustifolius. Later, immunoblotting and PCR-based ELISA assay were used to screen starting compounds and biotransformation products for their effects on hTERT protein levels and telomerase activation. All compounds showed improved telomerase activation compared to the control group.

CONCLUSIONS

As a result of biotransformation studies, seven new metabolites were obtained and characterized, verifying the potential of C. laburnicola as a biocatalyst. Additionally, the bioactivity results showed that this endophytic biocatalyst is unique in transforming the metabolites of its host to afford potent telomerase activators.

The Relevance of Telomerase and Telomere-Associated Proteins in B-Acute Lymphoblastic Leukemia

Telomeres and telomerase are closely linked to uncontrolled cellular proliferation, immortalization and carcinogenesis. Telomerase has been largely studied in the context of cancer, including leukemias. Deregulation of human telomerase gene hTERT is a well-established step in leukemia development. B-acute lymphoblastic leukemia (B-ALL) recovery rates exceed 90% in children; however, the relapse rate is around 20% among treated patients, and 10% of these are still incurable. This review highlights the biological and clinical relevance of telomerase for B-ALL and the implications of its canonical and non-canonical action on signaling pathways in the context of disease and treatment. The physiological role of telomerase in lymphocytes makes the study of its biomarker potential a great challenge. Nevertheless, many works have demonstrated that high telomerase activity or hTERT expression, as well as short telomeres, correlate with poor prognosis in B-ALL. Telomerase and related proteins have been proven to be promising pharmacological targets. Likewise, combined therapy with telomerase inhibitors may turn out to be an alternative strategy for B-ALL.

Skin Ageing: A Progressive, Multi-Factorial Condition Demanding an Integrated, Multilayer-Targeted Remedy

Of the human organs, skin is the most visible one that displays the manifestations of ageing. It has a very intricate microanatomical structure and performs several key physiological functions. The pathophysiology of cutaneous ageing is characterized by deterioration of structural stability and functional integrity, implying a continuous reduction in maximal function and reserve capacity, as a result of the accumulating damage due to both intrinsic and extrinsic factors. Elimination of unfavorable expressions associated with facial and cutaneous ageing is the key patient demand in aesthetic dermatology. Even though the progress has been made in nonsurgical therapies like fillers and lasers, non-invasive interventions by using skin care products designed for rejuvenation at an early stage are the most popular and accessible solution among people. In this review, we have scrutinized the ageing-associated cutaneous changes at molecular, cellular and tissue levels. To optimize the ageing process towards a healthy skin, we propose an integrated, multilayer-targeted intervention, which involves both topical application of anti-ageing formulations from outside and oral supplementation from inside. Additionally, several promising naturally derived ingredients are reviewed from an anti-aging perspective. Most of them possess various bioactivities and may contribute to the development of the mentioned anti-ageing remedy.

The Role and Mechanism of Polysaccharides in Anti-Aging

The elderly proportion of the population is gradually increasing, which poses a great burden to society, the economy, and the medical field. Aging is a physiological process involving multiple organs and numerous reactions, and therefore it is not easily explained or defined. At present, a growing number of studies are focused on the mechanisms of aging and potential strategies to delay aging. Some clinical drugs have been demonstrated to have anti-aging effects; however, many still have deficits with respect to safety and long-term use. Polysaccharides are natural and efficient biological macromolecules that act as antioxidants, anti-inflammatories, and immune regulators. Not surprisingly, these molecules have recently gained attention for their potential use in anti-aging therapies. In fact, multiple polysaccharides have been found to have excellent anti-aging effects in different animal models including Caenorhabditis elegans, Drosophila melanogaster, and mice. The anti-aging qualities of polysaccharides have been linked to several mechanisms, such as improved antioxidant capacity, regulation of age-related gene expression, and improved immune function. Here, we summarize the current findings from research related to anti-aging polysaccharides based on various models, with a focus on the main anti-aging mechanisms of oxidative damage, age-related genes and pathways, immune modulation, and telomere attrition. This review aims to provide a reference for further research on anti-aging polysaccharides.

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.

On the Potential Role of the Antioxidant Couple Vitamin E/Selenium Taken by the Oral Route in Skin and Hair Health

The relationship between oxidative stress and skin aging/disorders is well established. Many topical and oral antioxidants (vitamins C and E, carotenoids, polyphenols) have been proposed to protect the skin against the deleterious effect induced by increased reactive oxygen species production, particularly in the context of sun exposure. In this review, we focused on the combination of vitamin E and selenium taken in supplements since both molecules act in synergy either by non-enzymatic and enzymatic pathways to eliminate skin lipids peroxides, which are strongly implicated in skin and hair disorders.

The Role of Telomerase in Breast Cancer's Response to Therapy

Currently, breast cancer appears to be the most widespread cancer in the world and the most common cause of cancer deaths. This specific type of cancer affects women in both developed and developing countries. Prevention and early diagnosis are very important factors for good prognosis. A characteristic feature of cancer cells is the ability of unlimited cell division, which makes them immortal. Telomeres, which are shortened with each cell division in normal cells, are rebuilt in cancer cells by the enzyme telomerase, which is expressed in more than 85% of cancers (up to 100% of adenocarcinomas, including breast cancer). Telomerase may have different functions that are related to telomeres or unrelated. It has been shown that high activity of the enzyme in cancer cells is associated with poor cell sensitivity to therapies. Therefore, telomerase has become a potential target for cancer therapies. The low efficacy of therapies has resulted in the search for new combined and more effective therapeutic methods, including the involvement of telomerase inhibitors and telomerase-targeted immunotherapy.

Potential of Hibiscus sabdariffa L. and Hibiscus Acid to Reverse Skin Aging

Hibiscus sabdariffa L. (HS) has a long history of edible and medicinal uses. In this study, the biological activities of the extracts, chromatographic fractions, and hibiscus acid obtained from HS were evaluated for their potential bioactivities. Their ability to promote extracellular matrix synthesis in skin fibroblasts was evaluated by enzyme-linked immunosorbent assays. Their anti-inflammatory activity was evaluated in a nitric oxide (NO)–Griess inflammatory experiment. Furthermore, hibiscus acid was found to have a strong anti-oxidative stress effect through the establishment of an oxidative stress model induced by hydrogen peroxide. Several assays indicated that hibiscus acid treatment can effectively reduce extracellular adenosine triphosphate (ATP) secretion and carbonyl protein production, as well as maintain a high level of reduced/oxidized glutathione (GSH/GSSG) in skin cells, thus providing a possible mechanism by which hibiscus acid can counter antioxidative stress. The present study is the first to explore the reversing skin aging potential and the contributory component of HS.

Quercetin promotes cutaneous wound healing in mice through Wnt/β-catenin signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Oxytropis falcata Bunge is a legume distributed in Northwest China, which is mainly used to treat knife wounds and inflammation. Quercetin is a bioactive flavonoid in O. falcata and becomes a promising healing compound for its angiogenic and anti-inflammatory activities. However, the healing mechanism of quercetin in cutaneous wound remains elusive.

AIM OF THE STUDY

The purpose of this study was to evaluate the healing effect of quercetin on cutaneous wound models in vivo and in vitro, and to reveal the Wnt/β-catenin pathway and Telomerase reverse transcriptase (TERT) involved mechanisms.

MATERIALS AND METHODS

The effects of quercetin on the proliferation and migration of 4 kinds of skin cells were determined by CCK-8 and scratch assay. The wound-healing capacity of quercetin was evaluated in cutaneous wound model of C57BL/6 mice and the wound healing degree was observed by histological staining. The expressions of inflammatory factors, growth factors and the related proteins were detected via Western blot and RT-qPCR analyses. The molecular docking was adopted to evaluate the binding ability of quercetin and TERT.

RESULTS

Quercetin could promote both proliferation and migration of fibroblasts, and enhance cutaneous wound healing capacity in mice. Compared to the control group, the wound healing rates in low (1.5 mg/mL), medium (3.0 mg/mL) and high dose (6.0 mg/mL) quercetin groups reached 94.67%, 97.31% and 98.42%, respectively. Moreover, the dermal structure in quercetin treated mice restored normal and the content of collagen fiber became abundant after administration. The levels of inflammatory factors, including tumor necrosis factor-α, interleukin-1β and interleukin-6 were significantly reduced after quercetin administration. Among which, the level of IL-1β in cutaneous wound was 0.007 times higher than that of the control group when treated with quercetin of high dose (6.0 mg/mL). The improved level of GSH in quercetin treated cutaneous wounds also indicated its higher antioxidant ability. In addition, dose-dependent positive associations were found in the expression levels of vascular endothelial growth factor, fibroblast growth factor and alpha smooth muscle actin in quercetin treated cutaneous wounds. The significantly upregulated protein levels of Wnt and β-catenin further indicated the important role of quercetin in promoting wound healing in mice. According to molecular docking analysis, the formed hydrogen bonds between quercetin and Ala195, Gln308, Asn369 and Lys372 residues of TERT also indicated the indispensable role of TERT in improving wound healing capacity.

CONCLUSION

Quercetin effectively promoted cutaneous wound healing by enhancing the proliferation and migration of fibroblasts, as well as inhibiting inflammation and increasing the expression of growth factors in mice via Wnt/β-catenin signaling pathway and TERT. It provides a basis for a more thorough understanding of mechanism of action of O. falcata Bunge in the treatment of knife wounds and burns.