The Achilles' heel of senescent cells: from transcriptome to senolytic drugs

Clearance of senescent vascular smooth muscle cells retards aging-related restenosis following bioresorbable scaffolds implantation

In contrast to bioinert metal stents, the degradation of bioresorbable scaffolds (BRS) induces complex mechanical changes and accumulation of degradation products, potentially leading to adverse events following implantation into stenotic arteries. Atherosclerosis (AS) is a typical age-related disease, plaque formation and changes in vascular mechanical properties can significantly affect the process of restenosis and vascular repair after BRS implantation. The aging of vascular smooth muscle cells (VSMCs) is earlier than that of endothelial cells (ECs) and plays a decisive role in the mechanical properties of blood vessels. This study investigated the impact of senescent VSMCs (s-VSMCs) on the effectiveness of 3-D printed poly-l-lactide BRS implanted in the aged abdominal aortas of Sprague-Dawley rats over a 6-month period. Synthetic phenotype switch of s-VSMCs contribute to aging-related in-stent restenosis (ISR) and hinder neointima recovery, by reducing positive remodeling and impeding the neointima recovery of ECs. Further analysis indicated that the regulation of ECs was influenced by mechanoresponsive miRNAs and increased stiffness induced by s-VSMCs. To effectively eliminate s-VSMCs and accelerate vascular repair, two types of senolytic-coated BRS were developed and tested with ABT-263 and young plasma-derived exosomes. These results highlight the critical role of s-VSMCs in increasing aging-related ISR and delaying intima recovery following BRS implantation. The senolytic coatings, with their ability to clear senescent cells, promoted vascular repair. This study offers valuable insights for potential mechanisms responsible for the elevated ISR risks associated with BRS in aged aortas and the development of advanced BRS coatings.

Aging microvasculature: Effects on immune cell trafficking and inflammatory diseases

Leukocyte recruitment to sites of inflammation is vital for orchestrating an effective immune response. Key to this process is the ability of leukocytes to migrate through venular walls, engaging in sequential interactions with endothelial cells, pericytes, and the venular basement membrane. The aging process exerts profound effects on the molecular and functional properties of the vasculature, thereby influencing the profile and dynamics of leukocyte trafficking during inflammation. In this review, by focusing mainly on neutrophils, we summarize key examples of how the aged microvasculature and perivascular stroma cells promote dysregulated leukocyte-venular wall interactions and present the associated molecular mechanisms. Additionally, we discuss the functional implications of such aberrant leukocyte behavior to age-related and chronic inflammatory pathologies.

Exercise alleviates osteoporosis by regulating the secretion of the Senescent Associated Secretory Phenotype

As the elderly population grows, the number of patients with metabolic bone diseases such as osteoporosis has increased sharply, posing a significant threat to public health and social economics. Although pharmacological therapies for osteoporosis demonstrate therapeutic benefits, their prolonged use is associated with varying degrees of adverse effects. As a non-pharmacological intervention, exercise is widely recognized for its cost-effectiveness, safety, and lack of toxic side effects, making it a recommended treatment for osteoporosis prevention and management. Previous studies have demonstrated that exercise can improve metabolic bone diseases by modulating the Senescent Associated Secretory Phenotype (SASP). However, the mechanisms through which exercise influences SASP remain unclear. Therefore, this review aims to summarize the effects of exercise on SASP and elucidate the specific mechanisms by which exercise regulates SASP to alleviate osteoporosis, providing a theoretical basis for osteoporosis through exercise and developing targeted therapies.

The context-dependent effect of cellular senescence: From embryogenesis and wound healing to aging

Aging is characterized by a steady loss of physiological integrity, leading to impaired function and increased vulnerability to death. Cell senescence is a biological process that progresses with aging and is believed to be a key driver of age-related diseases. Senescence, a hallmark of aging, also demonstrates its beneficial physiological aspects as an anti-cancer, pro-regenerative, homeostatic, and developmental mechanism. A transitory response in which the senescent cells are quickly formed and cleared may promote tissue regeneration and organismal fitness. At the same time, senescence-related secretory phenotypes associated with extended senescence can have devastating effects. The fact that the interaction between senescent cells and their surroundings is very context-dependent may also help to explain this seemingly opposing pleiotropic function. Further, mitochondrial dysfunction is an often-unappreciated hallmark of cellular senescence and figures prominently in multiple feedback loops that induce and maintain the senescent phenotype. This review summarizes the mechanism of cellular senescence and the significance of acute senescence. We concisely introduced the context-dependent role of senescent cells and SASP, aspects of mitochondrial biology altered in the senescent cells, and their impact on the senescent phenotype. Finally, we conclude with recent therapeutic advancements targeting cellular senescence, focusing on acute injuries and age-associated diseases. Collectively, these insights provide a future roadmap for the role of senescence in organismal fitness and life span extension.

Senolytic treatment alleviates cochlear senescence and delays age-related hearing loss in C57BL/6J mice

BACKGROUND

Age-related hearing loss (ARHL) is a prevalent sensory deficit that significantly affects quality of life in older individuals. Cellular senescence contributes to various age-related degenerative disorders. However, its effect on ARHL remains unclear.

PURPOSE

The aim of this study was to explore the therapeutic potential of senolytics in attenuating cochlear senescence and delaying the progression of ARHL.

METHODS

The senolytic drugs dasatinib and quercetin (D + Q) were used to target senescent cells at different stages of ARHL in C57BL/6J mice. The impact of D + Q treatment on ARHL progression and cochlear degeneration was also assessed. Additionally, the protective effects of D + Q treatment were evaluated in HEI-OC1 auditory cells and cochlear explants. Transcriptomic analysis was conducted on cochlear explants subjected to different treatments.

RESULTS

D + Q treatment at an early stage of ARHL significantly delayed ARHL progression and alleviated cochlear degeneration in male and female C57BL/6J mice. Treatment of mice with normal hearing also mitigated age-related hair cell loss. In HEI-OC1 auditory cells, D + Q treatment exerted protective effects by alleviating the senescence-associated secretory phenotype (SASP). Transcriptomic analysis of cochlear explants revealed that downregulation of inflammatory cytokines and chemokines was involved in the beneficial effects of D + Q treatment against cellular senescence. Mechanistically, D + Q treatment alleviated hair cell senescence via binding to NF-κB and inhibiting its activity.

CONCLUSION

Senolytics may offer a novel therapeutic strategy for attenuating cochlear senescence and slowing the progression of ARHL.

Current strategies for senescence treatment: Focused on theranostic performance of nanomaterials

Age-related diseases imposed heavy burdens to the healthcare systems globally, while cell senescence served as one fundamental molecular/cellular basis for these diseases. How to tackle the senescence-relevant problems is a hotspot for biomedical research. In this review article, the hallmarks and molecular pathways of cell senescence were firstly discussed, followed by the introduction of the current anti-senescence strategies, including senolytics and senomorphics. With suitable physical or chemical properties, multiple types of nanomaterials were used successfully in senescence therapeutics, as well as senescence detection. Based on the accumulating knowledges for senescence, the rules of how to use these nanoplatforms more efficiently against senescence were also summarized, including but not limited to surface modification, material-cargo interactions, factor responsiveness etc. The comparison of these "senescence-selective" nanoplatforms to other treatment options (prodrugs, ADCs, PROTACs, CART etc.) was also given. Learning from the past, nanotechnology can add more choice for treating age-related diseases, and provide more (diagnostic) information to further our understanding of senescence process.

Molecular signatures of cellular senescence in cancer: a critical review of prognostic implications and therapeutic opportunities

Cellular senescence is a state of permanent loss of proliferative capacity. Therefore, cells that reach a senescent state prevent tumor initiation, acting as an anti-tumor mechanism. However, despite not being proliferative, senescent cells have high secretory activity, constituting the Senescence-Associated Secretory Phenotype (SASP). SASP includes thousands of soluble molecules and extracellular vesicles, through which senescent cells can affect other cells and the extracellular matrix. In advanced tumors, the enrichment of senescent cells can have anti- or pro-tumor effects depending on features like SASP composition, tumor microenvironment (TME) composition, the anatomic site, histopathologic characteristics of malignancy, and tumor molecular background. We reviewed the studies assessing the impact of the senescence status, measured by mRNA or lncRNA molecular signatures, in the prognosis and other clinically relevant information in cancer, including anti-tumor immunity and response to therapy. We discussed the pros and cons of different strategies to define those molecular signatures and the main limitations of the studies. Finally, we also raised clinical challenges regarding the crossroad between cellular senescence and cancer prognosis, including some therapeutic opportunities in the field.

Real-World Clinical Practice on Skin Rejuvenation Among Korean Board-Certified Dermatologists: Survey-Based Results

BACKGROUND

Skin rejuvenation has become an increasingly popular noninvasive approach to address age-related changes such as sagging, wrinkles, and skin laxity. Energy-based devices (EBDs) and injectables are widely used, but their application requires careful customization based on individual patient characteristics to optimize outcomes and minimize potential adverse effects.

OBJECTIVE

This study aimed to explore clinical practice patterns among board-certified dermatologists in South Korea, focusing on their strategies for tailoring skin rejuvenation treatments to individual patients, including the integration of EBDs, injectables, and senotherapeutics.

METHODS

A structured survey comprising 10 questions was administered to 13 experienced dermatologists specializing in skin rejuvenation. The survey covered treatment strategies for patients with varying facial fat volumes, pain management approaches, and the use of EBDs, injectables and senotherapeutics.

RESULTS

High-intensity focused ultrasound (HIFU) and radiofrequency (RF) were the most employed EBDs, often combined with injectables for enhanced outcomes. For patients with higher facial fat, HIFU and deoxycholic acid injections were preferred for contouring and tightening. For those with lower facial fat, biostimulatory agents such as poly-D, L-lactic acid and microneedle RF were favored to restore volume and elasticity. Pain management strategies included topical anesthetics and stepwise protocols. Although less commonly used, senotherapeutics were occasionally prescribed for specific conditions, such as melasma and extensive photoaging.

CONCLUSION

Dermatologists in South Korea employ a variety of patient-specific strategies for skin rejuvenation, combining various EBDs, injectables, and senotherapeutics. These findings highlight the importance of personalized treatment protocols and the need for further research to optimize treatment efficacy and safety.

Investigating the bidirectional interactions between senotherapeutic agents and human gut microbiota

Biological ageing is a time-dependent process that has implications for health and disease. Cellular senescence is a key driver in ageing and age-related diseases. Senotherapeutic agents have been shown to slow biological ageing by eliminating senescent mammalian cells. Given the increasing awareness of the gut microbiome in regulating human health, this study aimed to investigate the effects of senotherapeutic agents as pharmacological interventions on the human gut microbiota. In this study, the bidirectional effects of four senotherapeutic agents, quercetin, fisetin, dasatinib, and sirolimus, with the gut microbiota sourced from healthy human donors were investigated. The results revealed that quercetin was completely biotransformed by the gut microbiota within six hours, while dasatinib was the most stable of the four compounds. Additionally, metagenomic analysis confirmed that all four compounds increased the abundance of bacterial species associated with healthy ageing (e.g., Bacteroides fragilis, Bifidobacterium longum, and Veillonella parvula), and decreased the abundance of pathogenic bacteria primarily associated with age-related diseases (e.g., Enterococcus faecalis and Streptococcus spp.). The findings from this study provide a comprehensive understanding of the pharmacobiomics of senotherapeutic interventions, highlighting the potential of microbiome-targeted senolytics in promoting healthy ageing.

Immunosenescence in skeletal muscle: The role-play in cancer cachexia chessboard

With the increase in life expectancy, age-related conditions and diseases have become a widespread and relevant social burden. Among these, immunosenescence and cancer cachexia play a significant often intertwined role. Immunosenescence is the progressive aging decline of both the innate and adaptive immune systems leading to increased infection susceptibility, poor vaccination efficacy, autoimmune disease, and malignancies. Cancer cachexia affects elderly patients with cancer causing severe weight loss, muscle wasting, inflammation, and reduced response to therapies. Whereas the connections between immunosenescence and cancer cachexia have been raising attention, the molecular mechanisms still need to be completely elucidated. This review aims at providing the current knowledge about the interplay between immunosenescence, skeletal muscle, and cancer cachexia, analyzing the molecular pathways known so far to be involved. Finally, we highlight potential therapeutic strategies suited for elderly population aimed to block immunosenescence and to preserve muscle mass in cachexia, also presenting the analysis of the current state-of-the-art of related clinical trials.

Unraveling the functional and molecular interplay between cellular senescence and the unfolded protein response

Senescence is a complex cellular state that can be considered as a stress response phenotype. A decade ago, we suggested the intricate connections between unfolded protein response (UPR) signaling and the development of the senescent phenotype. Over the past ten years, significant advances have been made in understanding the multifaceted role of the UPR in regulating cellular senescence, highlighting its contribution to biological processes such as oxidative stress and autophagy. In this updated review, we expand these interconnections with the benefit of new insights, and we suggest that targeting specific components of the UPR could provide novel therapeutic strategies to mitigate the deleterious effects of senescence, with significant implications for age-related pathologies and geroscience.

Clinical application of mesenchymal stem cells in immunosenescence: a qualitative review of their potential and challenges

Aging leads to a gradual decline in immune function, termed immunosenescence, which significantly elevates the susceptibility to infections, cancers, and other aging-related diseases. Recent advancements have shed light on the molecular underpinnings of immune aging and pioneered novel therapeutic interventions to counteract its effects. Mesenchymal stem cells (MSCs)-a type of multipotent stromal cells with regenerative potential, low immunogenicity, and strong immunomodulatory properties-are increasingly recognized as a promising therapeutic option to reverse or alleviate immunosenescence-related dysfunction. This review systematically summarizes recent discoveries on how MSCs counteract immune aging, particularly their ability to rejuvenate aged immune cells and restore immune homeostasis. It also addresses key challenges, such as variations in MSC sources, donor variability, and the lack of standardized protocols, while proposing future directions to enhance therapeutic precision. Although preclinical and clinical studies highlight the potential of MSC-based strategies for delaying immunosenescence, critical issues remain unresolved, including long-term safety and efficacy, optimizing cell delivery systems, and elucidating context-specific mechanisms. Addressing these challenges will accelerate the development of MSC-based therapies to combat aging-associated immune decline.

Vascular senescence and aging: mechanisms, clinical implications, and therapeutic prospects

The aging vasculature is characterized by endothelial dysfunction, arterial stiffness, and increased susceptibility to vascular pathologies. Central to these changes is the process of cellular senescence, where endothelial and vascular smooth muscle cells lose their replicative and functional capacity and adopt a pro-inflammatory secretory phenotype. This review provides an overview of the key mechanisms underlying vascular senescence, including the p53/p21 and p16/Rb pathways, the senescence-associated secretory phenotype (SASP), and oxidative stress, examines its contribution to cardiovascular diseases in older adults, and highlights emerging therapeutic strategies aimed at delaying or reversing these age-related vascular changes. In vascular cells, DNA damage, oxidative stress, and chronic inflammation associated with aging converge to amplify senescence. Clinically, vascular senescence is linked with hypertension, atherosclerosis, and increased overall cardiovascular risk. Several interventions, ranging from senolytics to lifestyle factors, show promise in mitigating these changes; however, long-term studies are needed. Given that vascular senescence is a pivotal driver of cardiovascular pathology in aging, targeting senescent cells or their secretory phenotype may potentially offer new avenues for preventing or attenuating age-related vascular diseases. This review presents an updated and integrative overview of vascular senescence, connecting fundamental cellular mechanisms with their clinical manifestations and highlighting the most promising therapeutic interventions.

Aging at the Crossroads of Organ Interactions: Implications for the Heart

Aging processes underlie common chronic cardiometabolic diseases such as heart failure and diabetes. Cross-organ/tissue interactions can accelerate aging through cellular senescence, tissue wasting, accelerated atherosclerosis, increased vascular stiffness, and reduction in blood flow, leading to organ remodeling and premature failure. This interorgan/tissue crosstalk can accelerate aging-related dysfunction through inflammation, senescence-associated secretome, and metabolic and mitochondrial changes resulting in increased oxidative stress, microvascular dysfunction, cellular reprogramming, and tissue fibrosis. This may also underscore the rising incidence and co-occurrence of multiorgan dysfunction in cardiometabolic aging in the population. Examples include interactions between the heart and the lungs, kidneys, liver, muscles, and brain, among others. However, this phenomenon can also present new translational opportunities for identifying diagnostic biomarkers to define early risks of multiorgan dysfunction, gain mechanistic insights, and help to design precision-directed therapeutic interventions. Indeed, this opens new opportunities for therapeutic development in targeting multiple organs simultaneously to disrupt the crosstalk-driven process of mutual disease acceleration. New therapeutic targets could provide synergistic benefits across multiple organ systems in the same at-risk patient. Ultimately, these approaches may together slow the aging process itself throughout the body. In the future, with patient-centered multisystem coordinated approaches, we can initiate a new paradigm of multiorgan early risk prediction and tailored intervention. With emerging tools including artificial intelligence-assisted risk profiling and novel preventive strategies (eg, RNA-based therapeutics), we may be able to mitigate multiorgan cardiometabolic dysfunction much earlier and, perhaps, even slow the aging process itself.

Anti-senescence therapies: a new concept to address cardiovascular disease

Accumulation of senescent cells is an increasingly recognized factor in the development and progression of cardiovascular (CV) disease (CVD). Senescent cells of different types display a pro-inflammatory and matrix remodelling molecular programme, known as the 'senescence-associated secretory phenotype' (SASP), which has roots in (epi)genetic changes. Multiple therapeutic options (senolytics, anti-SASP senomorphics, and epigenetic reprogramming) that delete or ameliorate cellular senescence have recently emerged. Some drugs routinely used in the clinics also have anti-senescence effects. However, multiple challenges hinder the application of novel anti-senescence therapeutics in the clinical setting. Understanding the biology of cellular senescence, advantages and pitfalls of anti-senescence treatments, and patients who can profit from these interventions is necessary to introduce this novel therapeutic modality into the clinics. We provide a guide through the molecular machinery of senescent cells, systematize anti-senescence treatments, and propose a pathway towards senescence-adapted clinical trial design to aid future efforts.

Advancing T-cell immunotherapy for cellular senescence and disease: Mechanisms, challenges, and clinical prospects

Cellular senescence is a complex biological process with a dual role in tissue homeostasis and aging-related pathologies. Accumulation of senescent cells promotes chronic inflammation, tissue dysfunction, age-related diseases, and tumor suppression. Recent advancements in immunotherapy have positioned T cell-based approaches as precision tools for the targeted clearance of senescent cells, offering a novel avenue for anti-aging interventions. This review explores the molecular mechanisms underlying cellular senescence, focusing on its immunogenic features and interactions with T cells, including T-cell activation, antigen recognition, modulation of tumor microenvironment (TME), and immune evasion strategies. Innovations such as chimeric antigen receptor (CAR)-T cells, immune checkpoint therapies, and SASP-neutralizing approaches are highlighted as breakthrough strategies for enhancing senescent cell eradication. The integration of multi-omics and artificial intelligence is further catalyzing the development of personalized therapies to amplify immune surveillance and tissue rejuvenation. Clinically, T cell-based interventions hold promise for mitigating age-related pathologies and extending healthspan, yet challenges remain in optimizing target specificity, countering immunosuppressive niches, and overcoming immune senescence in aging populations. This review synthesizes current advances and challenges, highlighting the potential of T cell immunotherapy as a cornerstone of anti-aging medicine and emphasizing the need for interdisciplinary innovation to translate preclinical findings into transformative therapies for aging and age-related diseases.

Bioorthogonally Activatable Photosensitizer for NIR Fluorescence Imaging-Guided Highly Selective Elimination of Senescent Tumor Cells and Chemotherapy Enhancement

Chemotherapy is a primary modality in cancer treatment, but it may induce cellular senescence, which in turn triggers the release of senescence-associated secretory phenotypes (SASPs) that promote tumor growth and metastasis. To selectively identify senescent cells and mitigate their negative impact on cancer therapy, herein, we have developed a β-galactosidase (β-Gal)-activated and self-immobilizing photosensitizer CyGF-DBCO-T. This photosensitizer can be selectively activated and fluorescently label proteins in situ within senescent cells, enabling near-infrared (NIR) fluorescence imaging-guided photodynamic therapy (PDT) for the precise ablation of these cells. First, we developed an activatable NIR fluorescent probe CyGF-N3 that can specifically in situ label senescent cells. Subsequently, DBCO-T with free radicals underwent a bioorthogonal click reaction with activated CyGF-N3 in senescent cells to generate the photosensitizer CyO-DBCO-T. Under light irradiation, CyO-DBCO-T generated singlet oxygen (1O2) in situ, thereby enabling precise PDT with fluorescence guidance and photoactivation. Both CyGF-N3 and DBCO-T were encapsulated in biotinylated liposomes (CyGF-N3@LIP-B and DBCO-T@LIP-B), which enhanced their water solubility, tumor targeting, and in vivo circulation time. This promoted the accumulation of the probes in senescent tumor cells, thus enabling intense fluorescence imaging of tumor senescence regions in mice and enhancing the efficacy of PDT. This dual-module strategy, guided by fluorescence imaging for PDT, has achieved selective identification and precise ablation of senescent tumor cells in a chemotherapy-induced senescence model, effectively alleviating chemotherapy resistance and suppressing tumor growth.

Intersection of Cardio-Oncology: An Overview of Radiation-Induced Heart Disease in the Context of Tumors

Radiation-induced heart disease (RIHD) is a prevalent cardiovascular complication of radiation therapy, with coronary heart disease being the most common manifestation. Clinical presentations of RIHD vary and may include conduction abnormalities, ischemic heart disease, cardiomyopathy, heart failure, and valvular damage. Even low doses of radiation significantly increase the risk of cardiovascular disease, often associated with severe stenosis detected via angiography. Radiation-induced damage to the cardiac endothelium triggers inflammatory responses and oxidative stress, which contribute to the progression of atherosclerosis. This study explores how radiation activates multiple signaling pathways through the generation of reactive oxygen species, resulting in vascular endothelial damage, cellular senescence, inflammatory responses, and DNA damage. It further examines the impact of radiation on vascular integrity and tight junction proteins, leading to increased vascular permeability and infiltration by inflammatory cells. From a clinical perspective, we emphasize the challenges posed by the coexistence of tumors in many patients with RIHD, as tumors complicate the microenvironment and may have mutually reinforcing interactions with radiation-induced damage. We also discuss various therapeutic strategies, including novel approaches targeting cellular senescence and immune responses, with a focus on the potential use of navitoclax and IL-6 (interleukin-6) inhibitors to prevent irreversible cardiomyocyte fibrosis and ongoing vascular damage. In conclusion, RIHD is a multifaceted disease involving complex biological processes and signaling pathways. Early intervention and targeted therapies are crucial for improving patient outcomes. Future research should prioritize uncovering the molecular mechanisms of RIHD and developing more effective therapeutic strategies.

The Antiaging Potential of Dietary Plant-Based Polyphenols: A Review on Their Role in Cellular Senescence Modulation

Aging is a complex biological process characterized by a progressive decline in physiological functions and an increased risk of chronic diseases. A key mechanism of this process is cellular senescence, the permanent arrest of the cell cycle in response to stress or damage, which contributes to the accumulation of dysfunctional cells in tissues. Recent research has highlighted the role of polyphenols, bioactive compounds present in numerous plant-based foods, in positively modulating these processes. Polyphenols exert antioxidant effects, regulate gene expression and improve mitochondrial function, helping to delay cellular aging and prevent age-related diseases. In addition, some polyphenols exhibit senolytic properties, selectively eliminating senescent cells and promoting tissue regeneration. This review summarizes the current evidence on the effects of polyphenols on aging and cellular senescence, exploring the underlying molecular mechanisms and discussing their potential in nutritional strategies aimed at promoting healthy aging.

In vitro senescence and senolytic functional assays

A detailed understanding of aging biology and the development of anti-aging therapeutic strategies remain imperative yet inherently challenging due to the protracted nature of aging. Cellular senescence arises naturally through replicative exhaustion and is accelerated by clinical treatments or environmental stressors. The accumulation of senescent cells-defined by a loss of mitogenic potential, resistance to apoptosis, and acquisition of a pro-inflammatory secretory phenotype-has been implicated as a key driver of chronic disease, tissue degeneration, and organismal aging. Recent studies have highlighted the therapeutic promise of senolytic drugs, which selectively eliminate senescent cells. Compelling results from preclinical animal studies and ongoing clinical trials underscore this potential. However, the clinical translation of senolytics requires further pharmacological validation to refine selectivity, minimize toxicity, and determine optimal dosing. Equally important is the evaluation of senolytics' potential to restore tissue structure and function by reducing the senescent cell burden. In vitro tissue culture models offer a powerful platform to advance these efforts. This review summarizes the current landscape of in vitro systems used for inducing cellular senescence-referred to as "senescence assays"-and for screening senolytic drugs-referred to as "senolytic assays". We conclude by discussing key challenges to improving mechanistic insight, predictive accuracy, and clinical relevance in senolytic drug development, as well as emerging applications of senolytic therapies.

Quercetin Reduces Vascular Senescence and Inflammation in Symptomatic Male but Not Female Coronary Artery Disease Patients

Recent studies suggest that vascular senescence and its associated inflammation fuel the inflammaging to favor atherogenesis; whether these pathways can be therapeutically targeted in coronary artery disease (CAD) patients remains unknown. In a randomized, double-blind trial, 97 patients (78 men) undergoing coronary artery bypass graft surgery were treated with either quercetin (500 mg twice daily, 47 patients) or placebo (50 patients) for two days pre-surgery through hospital discharge. Primary outcomes were reduced inflammation and improved endothelial function ex vivo. Exploratory analyses included plasma proteomics and single-nuclei RNA sequencing of internal thoracic artery (ITA) samples. Quercetin treatment showed a trend toward reduced C-reactive protein at discharge (p = 0.073) and differentially modulated circulating inflammatory protein expression between men and women, with a pro-inflammatory effect of quercetin in females. Endothelial acetylcholine-induced relaxation improved significantly with quercetin (p = 0.049), with effects in men (p = 0.043) but not in women (p = 0.852). ITA transcriptomics revealed the overexpression of senescence and inflammaging pathways in male vascular cells, which quercetin reversed. In female cells, quercetin had minimal endothelial benefit and increased inflammaging in fibroblasts. In male cells, a candidate target of quercetin involves interactions between the receptor PLAUR and its ligands PLAU and SERPINE1. Post-operative atrial fibrillation incidence was significantly lower with quercetin, representing 4% of the patients compared to 18% in the placebo group (p = 0.033). In conclusion, short-term quercetin treatment effectively targeted vascular senescence in male CAD patients, improving inflammatory and functional outcomes. However, these benefits were not observed in female patients. Trial Registration: https://clinicaltrials.gov, NCT04907253.

A Critical Appraisal of the Utility of Targeting Therapy-Induced Senescence for Cancer Treatment

Cancer chemotherapy and radiotherapy are rarely successful in eliminating the entire tumor population, often leaving behind a subpopulation of senescent cells that can contribute to disease recurrence. These senescent tumor cells also secrete various chemokines and cytokines that may be tumor promoting and immunosuppressive. Recognition of the deleterious impact of therapy-induced senescence has led to the preclinical development of senolytic compounds that eliminate senescent cells, representing a potential strategy to enhance the efficacy of conventional and targeted anticancer therapy. However, it remains uncertain whether this strategy can or will be translated to the clinic. This review provides a summary of the recent preclinical literature supporting the use of senolytics as an adjunct for cancer treatment, discusses the limitations associated with their use in the current preclinical models, and provides perspectives on the clinical development of senolytics in cancer treatment regimens. Overall, preclinical studies support the potential of senolytics to enhance efficacy and prolong the antitumor activity of current standard-of-care cancer therapies that promote senescence. However, further work is needed to develop optimal senolytic agents with the appropriate combination of properties for clinical testing, specifically, activity in the context of therapy-induced senescence with acceptable tolerability.

Gut microbiota-dependent increase in phenylacetic acid induces endothelial cell senescence during aging

Endothelial cell senescence is a key driver of cardiovascular aging, yet little is known about the mechanisms by which it is induced in vivo. Here we show that the gut bacterial metabolite phenylacetic acid (PAA) and its byproduct, phenylacetylglutamine (PAGln), are elevated in aged humans and mice. Metagenomic analyses reveal an age-related increase in PAA-producing microbial pathways, positively linked to the bacterium Clostridium sp. ASF356 (Clos). We demonstrate that colonization of young mice with Clos increases blood PAA levels and induces endothelial senescence and angiogenic incompetence. Mechanistically, we find that PAA triggers senescence through mitochondrial H2O2 production, exacerbating the senescence-associated secretory phenotype. By contrast, we demonstrate that fecal acetate levels are reduced with age, compromising its function as a Sirt1-dependent senomorphic, regulating proinflammatory secretion and redox homeostasis. These findings define PAA as a mediator of gut-vascular crosstalk in aging and identify sodium acetate as a potential microbiome-based senotherapy to promote healthy aging.

SGLT2 inhibitors as a novel senotherapeutic approach

Cellular senescence is the permanent cessation of cell proliferation and growth. Senescent cells accumulating in tissues and organs with aging contribute to many chronic diseases, mainly through the secretion of a pro-inflammatory senescence-associated secretory phenotype (SASP). Senotherapeutic (senolytic or senomorphic) strategies targeting senescent cells or/and their SASP are being developed to prolong healthy lifespan and treat age-related pathologies. Sodium-glucose co-transporter 2 (SGLT2) inhibitors are a new class of anti-diabetic drugs that promote the renal excretion of glucose, resulting in lower blood glucose levels. Beyond their glucose-lowering effects, SGLT2 inhibitors have demonstrated protective effects against cardiovascular and renal events. Moreover, SGLT2 inhibitors have recently been associated with the inhibition of cell senescence, making them a promising therapeutic approach for targeting senescence and aging. This review examines the latest research on the senotherapeutic potential of SGLT2 inhibitors.

Modulation of senescent Lepr+ skeletal stem cells via suppression of leptin-induced STAT3‒FGF7 axis activation alleviates abnormal subchondral bone remodeling and osteoarthritis progression

BACKGROUND

Recent studies have suggested that targeting senescent cells in joint tissues may alleviate osteoarthritis (OA) progression. However, this strategy encounters significant challenges, partially due to the high degree of cellular heterogeneity in osteoarthritic tissues. Moreover, little information is available on the role of skeletal stem cell (SSC) senescence, as compared to differentiated cells, in OA progression.

METHODS

In this study, single-cell RNA sequencing (scRNA-seq) on articular cartilages and subchondral bones of the knee joints of mice with post-traumatic osteoarthritis (PTOA) were performed. Further in vivo and in vitro studies were performed to reveal the role and mechanisims of senescent SSCs during the development of OA lesions and progression by microCT, pathological analysis, and functional gain and loss experiments. The one-way ANOVA was used in multiple group data analysis.

RESULTS

scRNA-seq and pathological data demonstrated that the leptin receptors (Lepr) positive SSCs underwent cellular senescence during OA progression. In addition, the leptin-Lepr signaling pathway induced signal transducer and activator of transcription 3 (STAT3) expression in SSCs, which consequently augmented the transcription of fibroblast growth factor 7 (FGF7). Further scRNA-seq and in vivo analyses revealed that FGF7 exacerbated abnormal bone remodeling in subchondral bones and OA progression by enhancing bone formation and suppressing bone resorption. In vitro analysis revealed that FGF7 induced the osteogenic differentiation of SSCs but inhibited osteoclastogenesis in a concentration-dependent manner.

CONCLUSIONS

In summary, our findings demonstrate that the leptin-Lepr signaling pathway promotes SSC senescence and exacerbates subchondral bone remodeling by activating the STAT3-FGF7 axis during OA progression, which may shed light on novel therapeutic strategies for OA.

Aging and metabolic dysfunction-associated steatotic liver disease: a bidirectional relationship

In recent years, aging and cellular senescence have triggered an increased interest in corresponding research fields. Evidence shows that the complex aging process is involved in the development of many chronic liver diseases, such as metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH). In fact, aging has a tremendous effect on the liver, leading to a gradual decline in the metabolism, detoxification and immune functions of the liver, which in turn increases the risk of liver disease. These changes can be based on the aging of liver cells (hepatocytes, liver sinusoidal endothelial cells, hepatic stellate cells, and Kupffer cells). Similarly, patients with liver diseases exhibit increases in the aging phenotype and aging cells, often manifesting as faster physical functional decline, which is closely related to the promoting effect of liver disease on aging. This review summarizes the interplay between MASLD/MASH development and aging, aiming to reveal the complex relationships that exacerbate one another. Moreover, the corresponding schemes for delaying aging or treating diseases are discussed to provide a basis for the development of effective prevention and treatment strategies in the future.

Targeting signaling pathways in neurodegenerative diseases: Quercetin's cellular and molecular mechanisms for neuroprotection

BACKGROUND

Neurodegenerative diseases (NDs), including Alzheimer's disease, Parkinson's disease, and Huntington's disease, are complex and challenging due to their intricate pathophysiology and limited treatment options.

METHODS

This review systematically sourced articles related to neurodegenerative diseases, neurodegeneration, quercetin, and clinical studies from primary medical databases, including Scopus, PubMed, and Web of Science.

RESULTS

Recent studies have included quercetin to impact the cellular and molecular pathways involved in neurodegeneration. Quercetin, a flavonoid abundant in vegetables and fruits, is gaining attention for its antioxidant, anti-inflammatory, and antiapoptotic properties. It regulates signaling pathways such as nuclear factor-κB (NF-κB), sirtuins, and phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt). These pathways are essential for cellular survival, inflammation regulation, and apoptosis. Preclinical and clinical studies have shown that quercetin improves symptoms and pathology in neurodegenerative models, indicating promising outcomes.

CONCLUSIONS

The study explores the potential of incorporating laboratory research into practical medical treatment, focusing on quercetin's neuroprotective effects on NDs and its optimal dosage.

Characterization of Human Senescent Cell Biomarkers for Clinical Trials

There is an increasing need for biomarkers of senescent cell burden to facilitate the selection of participants for clinical trials. p16Ink4a is encoded by the CDKN2A locus, which produces five variant transcripts in humans, two of which encode homologous p16 proteins: p16Inka4a, encoded by p16_variant 1, and p16ɣ, encoded by p16_variant 5. While distinct quantitative polymerase chain reaction primers can be designed for p16_variant 5, primers for p16_variant 1 also measure p16_variant 5 (p16_variant 1 + 5). In a recent clinical trial evaluating the effects of the senolytic combination, dasatinib + quercetin (D + Q), on bone metabolism in postmenopausal women, we found that women in the highest tertile for T-cell expression of p16_variant 5 had the most robust skeletal responses to D + Q. Importantly, the assessment of p16_variant 5 was more predictive of these responses than p16_variant 1 + 5. Here, we demonstrate that in vitro, p16_variant 1 + 5 increased rapidly (Week 1) following the induction of DNA damage, whereas p16_variant 5 increased later (Week 4), suggesting that p16_variant 5 becomes detectable only when the abundance of senescent cells reaches some threshold. Further analysis identified a SASP panel in plasma that performed as well in identifying postmenopausal women with a positive skeletal response to D + Q. Collectively, our findings provide further support for the T-cell p16_variant 5 assay as a biomarker for selecting participants in clinical trials of senolytic interventions. In addition, our data indicate that correlated plasma SASP markers could be used in lieu of the more technically challenging T-cell p16 assay. Trial Registration: ClinicalTrials.gov identifier: NCT04313634.

Senescence profiling of monoclonal gammopathies reveals paracrine senescence as a crucial defense against disease progression

Multiple myeloma (MM) is a plasma cell (PC) malignancy that is preceded by monoclonal gammopathy of undetermined significance (MGUS) and/or smoldering multiple myeloma (SMM). MGUS and SMM PCs exhibit the same primary oncogenic abnormalities as MM but lack the end-organ damage that defines proliferative disease, suggesting that clonal PCs in these precursor conditions could exhibit senescence or senescence-like growth arrest. Herein we identified monoclonal gammopathy patient-derived PCs that exhibit senescence features and found that senescent PCs were significantly increased in MGUS patients compared to SMM or MM. Spatial analysis of senescent PCs in stable MGUS and SMM patient biopsies demonstrated the activation of local paracrine senescence in the bone marrow microenvironment. Stable MGUS and SMM patients also exhibited disease-specific senescence-associated secretory phenotype (SASP) signatures that significantly correlated with PC burden and clonal antibody. In contrast, progressing MGUS, SMM, and new MM patients lacked local paracrine senescence responses and robust activation of disease specific SASP signatures. Overall, these data suggest that failure to activate tumor-specific paracrine senescence responses is key to disease progression in monoclonal gammopathies.

Oleracein E Rejuvenates Senescent Hippocampal NSCs by Inhibiting the ERK1/2-mTOR Axis to Improve Cognitive Dysfunction in Vascular Dementia

Vascular dementia (VD) is one of the most prevalent forms of dementia, yet effective treatments remain limited. Our previous research identified hippocampal neural stem cells (hNSCs) senescence as a key contributor to VD progression and suggested that reducing hNSC senescence could help reverse cognitive impairment. In this study, we investigated whether Oleracein E (OE), a phenolic antioxidant alkaloid, could alleviate hNSC senescence and improve cognitive function in VD. Using a two-vessel occlusion mouse model of VD, we found that OE treatment significantly reduced hNSCs senescence, restored proliferation and neuronal differentiation capacities, and improved cognitive performance. Mechanistically, OE exerted its effects by inhibiting ERK1/2 phosphorylation and suppressing mTOR activation. Furthermore, pharmacological activation of mTOR with MHY1485 partially abolished the antisenescence effects of OE in hNSCs. These findings suggest that OE may counteract senescence-related neurogenesis dysfunction and cognitive decline in VD, highlighting its potential as a therapeutic intervention.

Low-Intensity Pulsed Ultrasound Treatment Selectively Stimulates Senescent Cells to Promote SASP Factors for Immune Cell Recruitment

As emerging therapeutic strategies for aging and age-associated diseases, various biochemical approaches have been developed to selectively remove senescent cells, but how physical stimulus influences senescent cells and its possible application in senolytic therapy has not been reported yet. Here we developed a physical method to selectively stimulate senescent cells via low-intensity pulsed ultrasound (LIPUS) treatment. LIPUS stimulation did not affect the cell cycle, but selectively enhanced secretion of specific cytokines in senescent cells, known as the senescence-associated secretory phenotype (SASP), resulting in enhanced migration of monocytes/macrophages and upregulation of phagocytosis of senescent cells by M1 macrophage. We found that LIPUS stimulation selectively perturbed the cellular membrane structure in senescent cells, which led to activation of the intracellular reactive oxygen species-dependent p38-NF-κB signaling pathway. Using a UV-induced skin aging mouse model, we confirmed enhanced macrophage infiltration followed by reduced senescent cells after LIPUS treatment. Due to the advantages of ultrasound treatment, such as non-invasiveness, deep penetration capability, and easy application in clinical settings, we expect that our method can be applied to treat various senescence-associated diseases or combined with other established biochemical therapies to enhance efficacy.

A new clinical age of aging research

Aging is a major risk factor for a variety of diseases, thus, translation of aging research into practical applications is driven by the unmet need for existing clinical therapeutic options. Basic and translational research efforts are converging at a critical stage, yielding insights into how fundamental aging mechanisms are used to identify promising geroprotectors or therapeutics. This review highlights several research areas from a clinical perspective, including senescent cell targeting, alleviation of inflammaging, and optimization of metabolism with endogenous metabolites or precursors. Refining our understanding of these key areas, especially from the clinical angle, may help us to better understand and attenuate aging processes and improve overall health outcomes.

Apoptotic priming in senescence predicts specific senolysis by quantitative analysis of mitochondrial dependencies

Cellular senescence contributes to a variety of pathologies associated with aging and is implicated as a cellular state in which cancer cells can survive treatment. Reported senolytic drug treatments act through varying molecular mechanisms, but heterogeneous efficacy across the diverse contexts of cellular senescence indicates a need for predictive biomarkers of senolytic activity. Using multi-parametric analyses of commonly reported molecular features of the senescent phenotype, we assayed a variety of models, including malignant and nonmalignant cells, using several triggers of senescence induction and found little univariate predictive power of these traditional senescence markers to identify senolytic drug sensitivity. We sought to identify novel drug targets in senescent cells that were insensitive to frequently implemented senolytic therapies, such as Navitoclax (ABT-263), using quantitative mass spectrometry to measure changes in the senescent proteome, compared to cells which acquire an acute sensitivity to ABT-263 with senescence induction. Inhibition of the antioxidant GPX4 or the Bcl-2 family member MCL-1 using small molecule compounds in combination with ABT-263 significantly increased the induction of apoptosis in some, but not all, previously insensitive senescent cells. We then asked if we could use BH3 profiling to measure differences in mitochondrial apoptotic priming in these models of cellular senescence and predict sensitivity to the senolytics ABT-263 or the combination of dasatinib and quercetin (D + Q). We found, despite being significantly less primed for apoptosis overall, the dependence of senescent mitochondria on BCL-XL was significantly correlated to senescent cell killing by both ABT-263 and D + Q, despite no significant changes in the gene or protein expression of BCL-XL. However, our data caution against broad classification of drugs as globally senolytic and instead provide impetus for context-specific senolytic targets and propose BH3 profiling as an effective predictive biomarker.

Cdkn1a silencing restores myoblast differentiation by inducing selective apoptosis in senescent cells

BACKGROUND

Sarcopenia, characterized by a progressive loss of skeletal muscle mass and function, is associated with the accumulation of senescent muscle stem cells, which impair muscle regeneration and contributes to the decline in muscle health. Cdkn1a, which encodes p21, is a well-known marker of cellular senescence. However, it remains unclear whether p21 inhibition eliminates senescent myoblasts and restores the differentiation capacity.

METHODS

We performed transcriptomic analysis to identify genes related to aging-induced sarcopenia using 21 month-old Sprague-Dawley rats. To investigate the specific role of Cdkn1a gene in muscle aging, we used an in vitro model of ceramide-induced senescence in myoblasts, which was verified by the upregulation of p21 and increased senescence-associated beta-galactosidase (SA-β-gal) staining. To inhibit p21, we treated myoblasts with small interfering RNA (siRNA) targeting Cdkn1a. Using fluorescence-activated cell sorting, we separated subpopulations of cells with high or low caspase 3/7 activity. Protein expression related to myogenesis, muscle atrophy, protein synthesis, and apoptosis were quantified by western blotting.

RESULTS

In our transcriptomic analysis, we identified Cdkn1a as an upregulated gene in both the soleus and white gastrocnemius muscles of aged rats, among 36 commonly upregulated genes. The upregulation of Cdkn1a appears to be linked to mitochondrial dysfunction and cellular senescence, underscoring its significance in sarcopenia pathogenesis. C2-ceramide treatment effectively induced senescence, as evidenced by increased p21 expression, enhanced SA-β-gal staining, decreased myogenesis, and increased apoptosis. Knockdown of p21 in ceramide-treated myoblasts significantly reduced SA-β-gal-positive cells, restored cell proliferation, reduced the expression of senescence-associated cytokines (i.e., interleukin (IL)-6 and tumor necrosis factor (TNF)-α), and selectively induced apoptosis in the senescent cell population, demonstrating a senolytic effect. Notably, p21 inhibition also improved differentiation of myoblasts into myotubes, as indicated by increased myosin heavy chain expression and improvements in myotube diameter and fusion index.

CONCLUSIONS

Our data suggest that p21 inhibition selectively eliminates senescent cells while simultaneously enhancing the regenerative capacity of healthy myoblasts, which may combine to improve muscle regeneration and promote myogenesis, ultimately improving muscle health and function in aged individuals.

Senolytic therapy reduces inflammation in epithelial cells from COPD patients and in smoke-exposure mice

Introduction

Chronic obstructive pulmonary disease (COPD) is a disease of accelerated lung aging, with increased numbers of senescent cells found within the COPD Lung. Senescent cells may drive pathology by causing defective tissue repair and driving chronic inflammation via the release of inflammatory mediators known as the senescence-associated secretory phenotype (SASP). Senolytics are a new class of drugs that selectively remove senescent cells but have not previously been studied in COPD. We examined whether senescent cells are maintained during differentiation of COPD airway epithelial cells at the air-liquid interface and examined the role of the senolytic combination of dasatinib and quercetin on these cells and in a smoke-exposure mouse model.

Methods

Non-smoker and COPD bronchial epithelial cells were differentiated at air-liquid interface (ALI). Senescence markers (p16INKA and p21WAF1) were determined using Western blotting and SASP factors via Olink proteomics and Meso Scale Diagnostics (MSD). Cells and 11 days cigarette smoke (CS)-exposed mice were treated with the senolytic cocktail of dasatinib and quercetin (D + Q).

Results

Increased senescence markers were maintained in COPD ALI epithelium when differentiated at air-liquid interface, and treatment with D + Q reduced senescence markers, proteases, and Th2 cytokines. Therapeutic oral treatment of D + Q to CS-exposed mice reduced senescence burden while reducing inflammatory cell infiltrates and mouse CXCL1.

Conclusion

COPD subjects show increased airway epithelial senescence, and these cells can be cleared therapeutically using the senolytic cocktail of D + Q, reducing broad-spectrum pulmonary inflammation in vitro and in vivo.

Identification of Nitric Oxide Donating Dasatinib Derivatives with Intraocular Pressure Lowering and Senolytic Activities

Based on two major risk factors of glaucoma, elevated intraocular pressure (IOP) and senescence, two new series of nitric oxide (NO) donating dasatinib derivatives 1a-f, 2a-f were designed, synthesized, and biologically evaluated. The results demonstrated that the most active compound 2e effectively released NO and increased the concentration of 3',5'-cyclic guanosine monophosphate in human trabecular meshwork cells, as well as maintained senolytic activity. Topical administration of 2e in chronic ocular hypertension (COHT) glaucoma mice not only significantly eliminated senescent cells in retina but also exhibited potent retinal ganglion cells (RGCs) surviving, IOP lowering, and visual function protection activities, which were superior to those of dasatinib. Compared with younger adult mice, aged COHT mice resulted in more severe RGCs loss, while 2e demonstrated a greater capacity to improve RGCs survival. Our findings show that dual IOP lowering and senolytic functions could be a promising therapeutic strategy for glaucoma, particularly in older patients.

Evaluation of exploratory fluid biomarkers from a phase 1 senolytic trial in mild Alzheimer's disease

Senescent cell accumulation contributes to the progression of age-related disorders including Alzheimer's disease (AD). Clinical trials focused on cellular senescence are in early stages and have yet to establish reliable outcome measures reflecting senescent cell burden or response to senolytics, therapeutics that clear senescent cells. Results from the first open-label trial of senolytics, dasatinib plus quercetin (D ​+ ​Q), in older adults (N ​= ​5) with early AD demonstrated central nervous system penetration of dasatinib and favorable safety and tolerability. Herein, we present exploratory analyses of senescence and AD-associated analytes in blood, cerebrospinal fluid (CSF) and urine from this study in effort to guide biomarker development for future senolytic trials. Immunoassays, mass spectrometry and transcriptomics were performed and changes in analyte levels were assessed from baseline to post-treatment using paired t-tests. Targeted cytokine and chemokine analyses revealed increases in plasma fractalkine and MMP-7 and CSF IL-6 from baseline to post-treatment. Mass spectrometry indicated stable levels of amyloid β and tau proteins in CSF, unchanged urinary metabolites, and modest treatment-associated lipid profile changes. Targeted transcriptomic analysis of peripheral blood mononuclear cells indicated downregulation of inflammatory genes including FOS, FOSB, IL1β, IL8, JUN, JUNB, PTGS2. The levels and treatment responses of the analytes identified here may help inform trial design and outcomes for senolytic studies. Independent validation will be necessary to develop standardized biomarker panels across senolytic trials for AD. ClinicalTrials.gov: NCT04063124.

Fisetin Clears Senescent Cells Through the Pi3k-Akt-Bcl-2/Bcl-xl Pathway to Alleviate Diabetic Aortic Aging

Vascular aging is a major contributor to age-related cardiovascular diseases (CVDs) and type 2 diabetes mellitus (T2DM) induced early arterial aging and excessive senescent cells (SCs) burden in vessels. Inhibiting cellular senescence or eliminating SCs could effectively improve aging-related CVDs. Fisetin, a flavonoid extracted from cotinus coggygria scop, has shown potential in alleviating aging by clearing SCs. This study investigated the unexplored mechanisms and efficacy of fisetin in alleviating T2DM-related aortic aging. The T2DM mouse model was induced using a high-fat diet and low-dose streptozotocin injection. Chronic fisetin treatment's protective effects against aortic aging were assessed via senescence-associated beta-galactosidase (SA-β-Gal) staining, histopathology, and vasomotor function. RNA-sequencing and western blotting identified relevant signaling pathways and protein expression. Fisetin's effects on SCs and senescence-associated secretory phenotype (SASP) factors were evaluated through cell viability, apoptosis, and co-culture assays. Docking simulations suggested fisetin as a potential Phosphoinositide 3-kinase (Pi3k) inhibitor. In vivo, chronic fisetin treatment reduced aortic SCs burden, alleviating T2DM-related and natural aortic aging. In vitro, fisetin selectively induced apoptosis of senescent endothelial cells via regulating the Pi3k-Protein Kinase B (Akt)-B-cell lymphoma (Bcl)-2/Bcl-xl pathway and suppressed SASP and its detrimental effects. Furthermore, fisetin combined with metformin therapy showed superior anti-aging effects on T2DM-related aortic aging compared to metformin monotherapy. In conclusion, chronic fisetin treatment alleviates T2DM-related aortic aging via clearing the SCs burden and abrogating the SASP factors. Fisetin combined with metformin therapy might be a potential therapeutic strategy for T2DM-related CVDs.

Glutaminase-responsive nano-carrier for precise rejuvenation of senescent cells by restoring autophagy in chronic kidney disease treatment

Cellular senescence disrupts tissue homeostasis and diminishes physiological integrity, leading to the accumulation of senescent cells (SCs) in multiple senescence-associated diseases such as chronic kidney disease (CKD). Treatment of SCs has been approved to be a feasible approach to these diseases. However, curing SCs in different cell types remains challenging. In this study, we leveraged the high expression of glutaminase (GLS) in SCs to develop a drug delivery system utilizing γ-poly glutamic acid (γ-PGA) conjugated with octadecylamine (ODA) to encapsulate rapamycin (RP), resulting in a GLS-responsive drug delivery system, designated as RPPO. In a model of drug induced senescence, the γ-PGA component of RPPO was degraded by cellular GLS, facilitating the release of encapsulated RP and rejuvenating SCs by restoring the autophagic capacity. Additionally, in a model of CKD in mice, RPPO enhanced recovery by rejuvenating SCs, reducing fibrosis, and alleviating inflammation. Thus, this senescent cell-responsive drug delivery system presents a novel approach for the treatment of CKD.

Attenuation of Cellular Senescence and Improvement of Osteogenic Differentiation Capacity of Human Liver Stem Cells Using Specific Senomorphic and Senolytic Agents

Expansion of adult stem cells in culture increases the percent of senescent cells, reduces their differentiation capacity and limits their clinical use. Here, we investigated whether treatment with certain senotherapeutic drugs would reduce the accumulation of senescent cells during expansion of human liver stem cells (HLSCs) while maintaining their differentiation capacity. Our results demonstrate that chronic treatment with the senomorphic XJB-5-131 or the senolytics cocktail D + Q reduced the number of senescent cells and significantly reduced the expression of senescence-associated genes and several inflammatory SASP factors in later passage HLSCs. Additionally, treatment with XJB-5-131 and D + Q improved the capacity of HLSCs to undergo osteogenic differentiation following extensive in vitro expansion. Overall, our data demonstrate that treatment with XJB-5-13 or D + Q results in a reduction in the percentage of replication-induced senescent HLSCs and likely other types of adult stem cells and improve the potential therapeutic use of later passage human stem cells.

A bibliometric and visual analysis of the impact of senescence on tumor immunotherapy

Background

Recently, many studies have focused on the relationship between senescence and immunotherapy in cancer treatment. However, relatively few studies have examined the intrinsic links between the three. Whether these studies can act synergistically in the fight against cancer and the specific links between them are still unclear.

Methods

We extracted, quantified, and visualized data from the literature (n = 2396) for the period 2004-2023 after rigorous quality control using citespace, GraphPad Prism, the R software package, and VOSviewer.

Results

Linear fit analyses were generated to predict the number of annual publications and citations as a function of the top-performing authors, journals, countries, and affiliations academically over the past two decades such as Weiwei, Aging-us, China, and the UT MD Anderson Cancer Center. Vosviewer-based hierarchical clustering further categorized study characteristics into six clusters, including two major clusters of immunotherapy research, immunosenescence-related research factors, and timeline distributions suggesting that cellular senescence and tumor progression is a relatively new research cluster that warrants further exploration and development. Study characterization bursts and linear regression analyses further confirmed these findings and revealed other important results, such as aging (a = 1.964, R² = 0.6803) and immunotherapy (a = 16.38, R² = 0.8812). Furthermore, gene frequency analysis in this study revealed the most abundant gene, APOE, and SIRT1-7 proteins.

Conclusion

The combination of aging therapies with tumor immunotherapies is currently in its preliminary stages. Although senescence has the greatest impact on ICB therapies, mechanistic investigations, and drug development for APOE and sirt1-7 (Sirtuins family) targets may be the key to combining senescence therapies with immunotherapies in the treatment of tumors.

Identification of markers for neurescence through transcriptomic profiling of postmortem human brains

Neuronal senescence (i.e., neurescent) is an important hallmark of aging and neurodegeneration, but it remains poorly characterized in the human brain due to the lack of reliable markers. This study aimed to identify neurescent markers based on single-nucleus transcriptome data from postmortem human prefrontal cortex. Using an eigengene approach, we integrated three gene panels: a) SenMayo, b) Canonical Senescence Pathway (CSP), and c) Senescence Initiating Pathway (SIP), to identify neurescent signatures. We found that paired markers outperform single markers; for instance, by combining CDKN2D and ETS2 in a decision tree, a high accuracy of 99% and perfect specificity (100%) were achieved in distinguishing neurescent. Differential expression analyses identified 324 genes that are overexpressed in neurescent. These genes showed significant associations with important neurodegeneration-related pathways including Alzheimer's disease, Parkinson's disease, and Huntington's disease. Interestingly, several of these overexpressed genes are linked to mitochondrial dysfunction and cytoskeletal dysregulation. These findings provide valuable insights into the complexities of neurescent, emphasizing the need for further exploration of histologically viable markers and validation in broader datasets.

Is Senolytic Therapy in Cardiovascular Diseases Ready for Translation to Clinics?

Aging is a predominant risk factor for cardiovascular diseases. There is evidence demonstrating that senescent cells not only play a significant role in organism aging but also contribute to the pathogenesis of cardiovascular diseases in younger ages. Encouraged by recent findings that the elimination of senescent cells by pharmacogenetic tools could slow down and even reverse organism aging in animal models, senolytic drugs have been developed, and the translation of results from basic research to clinical settings has been initiated. Because numerous studies in the literature show beneficial therapeutic effects of targeting senescent cells in cardiomyopathies associated with aging and ischemia/reperfusion and in atherosclerotic vascular disease, senolytic drugs are considered the next generation of therapies for cardiovascular disorders. However, recent studies have reported controversial results or detrimental effects caused by senolytic therapeutic approaches, including worsening of cardiac dysfunction, instability of atherosclerotic plaques, and even an increase in mortality in animal models, which challenges the translation of senolytic therapy into the clinical practice. This brief review article will focus on (1) analyzing and discussing the beneficial and detrimental effects of senolytic therapeutic approaches in cardiovascular diseases and cardiovascular aging and (2) future research directions and questions that are essential to understand the controversies and to translate preclinical results of senolytic therapies into clinical practice.

Senescent cell reduction does not improve recovery in mice under experimental autoimmune encephalomyelitis (EAE) induced demyelination

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by immune cell-driven demyelination and progressive neurodegeneration. Senescent cells (SCs) have recently been observed in chronic MS lesions indicating their possible involvement in disease progression. However, the role of SCs and the potential therapeutic benefit of their reduction through senolytic therapy remains to be determined in experimental autoimmune encephalomyelitis (EAE), a widely used preclinical model of MS. Here, we show that senescent-like myeloid cells accumulate in the spinal cord parenchyma and meninges in mice after myelin oligodendrocyte glycoprotein (MOG33-55) EAE induction. Treatment with the senolytic cocktail, Dasatinib and Quercetin (DQ), effectively reduces the senescent-like myeloid cells, but this does not translate into improved clinical outcomes in EAE mice. Increasing DQ dosage or using INK-ATTAC transgenic mice also failed to ameliorate EAE severity. Additionally, histopathological analysis shows no significant differences in demyelination or axonal degeneration between treated and control groups. Our findings indicate that senescent-like myeloid cells are present in an immune-mediated demyelinating model of MS and can be reduced through senolytic therapy with Dasatinib and Quercetin. However, their reduction through DQ does not significantly impact inflammation or recovery, suggesting that the therapeutic potential of senolytics as disease-modifying drugs in MS may be limited.

Regulation of cellular senescence in tumor progression and therapeutic targeting: mechanisms and pathways

Cellular senescence, a stable state of cell cycle arrest induced by various stressors or genomic damage, is recognized as a hallmark of cancer. It exerts a context-dependent dual role in cancer initiation and progression, functioning as a tumor suppressor and promoter. The complexity of senescence in cancer arises from its mechanistic diversity, potential reversibility, and heterogeneity. A key mediator of these effects is the senescence-associated secretory phenotype (SASP), a repertoire of bioactive molecules that influence tumor microenvironment (TME) remodeling, modulate cancer cell behavior, and contribute to therapeutic resistance. Given its intricate role in cancer biology, senescence presents both challenges and opportunities for therapeutic intervention. Strategies targeting senescence pathways, including senescence-inducing therapies and senolytic approaches, offer promising avenues for cancer treatment. This review provides a comprehensive analysis of the regulatory mechanisms governing cellular senescence in tumors. We also discuss emerging strategies to modulate senescence, highlighting novel therapeutic opportunities. A deeper understanding of these processes is essential for developing precision therapies and improving clinical outcomes.

Endothelial dysfunction in the aging kidney

Global population aging is an escalating challenge in modern society, especially as it impairs the function of multiple organs and increases the burden of age-related diseases. The kidneys, in particular, experience function decline, reduced regenerative capacity, and increased susceptibility to injury as they age. As a result, the prevalence of chronic kidney disease (CKD) rises with aging, further contributing to the growing health burden in older populations. One of the key factors in this process is the dysfunction of specialized renal endothelial cells (RECs), which are essential for maintaining kidney health by regulating blood flow and supporting filtration, solute and water reabsorption, and vascular integrity. As the kidneys age, REC dysfunction drives vascular and microenvironmental changes, contributing to the overall decline in kidney function. In this review, we outline the structural and functional effects of aging on the kidney's macrovascular and microvascular compartments and provide a phenotypic description of the aged endothelium. We particularly focus on the molecular and metabolic rewiring driving and sustaining growth-arrested EC senescence phenotype. We finally give an overview of senotherapies acting on ECs, especially of those modulating metabolism. Given that the pathophysiological processes underlying kidney aging largely overlap with those observed in CKD, REC rejuvenation could also benefit patients with CKD. Moreover, such interventions may hold promise in improving the outcomes of aged kidney transplants. Hence, advancing our understanding of REC and kidney aging will create opportunities for innovations that could improve outcomes for both elderly individuals and patients with CKD.

Senescent brain cell types in Alzheimer's disease: Pathological mechanisms and therapeutic opportunities

Cellular senescence is a cell state triggered by programmed physiological processes or cellular stress responses. Stress-induced senescent cells often acquire pathogenic traits, including a toxic secretome and resistance to apoptosis. When pathogenic senescent cells form faster than they are cleared by the immune system, they accumulate in tissues throughout the body and contribute to age-related diseases, including neurodegeneration. This review highlights evidence of pathogenic senescent cells in the brain and their role in Alzheimer's disease (AD), the leading cause of dementia in older adults. We also discuss the progress and challenges of senotherapies, pharmacological strategies to clear senescent cells or mitigate their toxic effects, which hold promise as interventions for AD and related dementias (ADRD).

Depletion of senescent cells improves surgery-induced neuroinflammation in aged mice

Aging has been identified as a leading risk factor for many diseases, including neurodegenerative disorders. While cellular senescence has been linked to age-related neurodegenerative conditions, its involvement in peripheral stress-associated brain disorders is just beginning to be explored. In this study, we investigated the impact of senescent cells on peripheral stress-induced neuroinflammation using orthopedic surgery as a model. Our results demonstrate an increased accumulation of senescent cells and neuroinflammation in the aged mouse hippocampus following surgery. Intermittent treatment of the mice with the senolytic drugs dasatinib and quercetin (D/Q) showed a significant reduction in surgery-induced senescent cell burden. This reduction in senescent cell accumulation was correlated with reduced surgery-induced neuroinflammation, as evidenced by decreased glial cell activity. Consistent with these observations, we also observed reduced levels of proinflammatory senescence-associated secretory phenotype factors in circulation, following fracture surgery, in mice treated with D/Q. Overall, our findings underscore the pivotal role of cellular senescence in surgery-induced neuroinflammation and highlight the therapeutic potential of eliminating senescent cells as a potential strategy to manage peripheral stress-induced neuroinflammatory conditions.

"Thin endometrium" at single-cell resolution

Thin endometrium is defined as an endometrial thickness of less than 7 mm in the midluteal phase of the menstrual cycle, a condition often seen in women of childbearing age with a history of uterine trauma, such as dilation and curettage or intrauterine adhesion separation. This inadequate thickness poses a substantial threat to endometrial receptivity and subsequent pregnancy, particularly during infertility treatments. Despite efforts to stimulate endometrial growth through agents such as high doses of estrogen, improvements in both endometrial thickness and pregnancy rates have been marginal. Consequently, it is referred to as "unresponsive endometrium or refractory thin endometrium." To explore novel therapeutic avenues, a deeper understanding of the underlying mechanisms is urgently needed. In this review, we examine recent single-cell sequencing studies that have identified key alterations in cell populations, signaling pathways, and cell-cell communication in the endometrium during the late proliferative phase, comparing normal endometrium and thin endometrium following uterine injuries. Evidence suggests that endometrial injury acted as a primary contributor, initiating an accelerated aging process across diverse cell types and establishing an environment characterized by immune incompetence and dysfunction. Senescence, a consequence of this injury, may impede endometrial proliferation, disrupt vascular development, and lead to fibrosis, creating a milieu of abnormal receptivity-a critical downstream event associated with implantation failure and infertility. Addressing these identified challenges necessitates advancing research to comprehend and target the key factors contributing to thin endometrium, a crucial step for clinical translation.

Comparative Analysis of the Therapeutic Potential of Extracellular Vesicles Secreted by Aged and Young Bone Marrow-Derived Mesenchymal Stem Cells in Osteoarthritis Pathogenesis

Osteoarthritis (OA), a joint disease, burdens global healthcare due to aging and obesity. Recent studies show that extracellular vesicles (EVs) from bone marrow-derived mesenchymal stem cells (BMSCs) contribute to joint homeostasis and OA management. However, the impact of donor age on BMSC-derived EV efficacy remains underexplored. In this study, we investigated EV efficacy from young BMSCs (2-month-old) in mitigating OA, contrasting them with EVs from aged BMSCs (27-month-old). The study used destabilisation of the medial meniscus (DMM) surgery on mouse knee joints to induce accelerated OA. Cartilage degeneration markers and senescence markers' expression levels were investigated in response to EV treatment. The therapeutic impact of EVs on chondrocytes under inflammatory responses was also evaluated. Despite having similar morphologies, EVs from young BMSCs markedly decreased senescence and improved chondroprotection by activating the PTEN pathway while simultaneously suppressing the upregulation of the PI3K/AKT pathways, proving to be more effective than those from older BMSCs in vitro. Furthermore, intraperitoneal injections of EVs from young donors significantly mitigated OA progression by preserving cartilage and reducing synovitis in a surgical OA model using DMM in mice. These findings highlight that donor age as a critical determinant in the therapeutic potential of BMSC-derived EVs for clinical use in OA treatment.