Benefits of Metformin in Attenuating the Hallmarks of Aging

Extinguishing the flames of inflammation: retardant effect of chlorquinaldol on NLRP3-driven diseases

BACKGROUND

NLRP3 inflammasome immoderate activation results in the occurrence of various inflammatory diseases, but the clinic medications targeting NLRP3 inflammasome are still not available currently. The strategy of drug repurposing can reorient the direction of therapy, which is an indispensable method of drug research. In this study, an antimicrobial agent chlorquinaldol (CQ) was conducted to assess the effect on NLRP3 inflammasome and novel clinical value on NLRP3-driven diseases.

METHODS

The effect of CQ on NLRP3 inflammasome activation and pyroptosis was studied in mouse and human macrophages. ASC oligomerization, intracellular potassium, reactive oxygen species production, and NLRP3-ASC interaction were used to evaluate the suppression mechanism of CQ on inflammasome activation. Finally, the ameliorative effects of CQ in the model of LPS-induced peritonitis, dextran sodium sulfate (DSS)-induced colitis, and monosodium urate (MSU)-induced gouty arthritis were evaluated in vivo.

RESULTS

CQ is a highly powerful NLRP3 inhibitor that has feeble impact on the NLRC4 or AIM2 inflammasome activation in mouse and human macrophages. Further study indicated that CQ exhibits its suppression effect on NLRP3 inflammasome by blocking NLRP3-ASC interaction and hydroxyl on the benzene ring is vital for the assembly and activation of NLRP3 inflammasome. Furthermore, in vivo experiments demonstrated that administration of CQ has outstanding therapeutic action on LPS-induced peritonitis, DSS-induced colitis, and MSU-induced gouty inflammation in mice.

CONCLUSIONS

Collectively, the current study discoveries the antimicrobial agent CQ as a potentially specific NLRP3 inhibitor, and its use provides a feasible therapeutic approach for the treatment of NLRP3-driven diseases.

Metformin and fibromyalgia pathophysiology: current insights and promising future therapeutic strategies

Fibromyalgia (FM) is a complex, chronic pain syndrome characterized by widespread musculoskeletal pain, fatigue, and cognitive disturbances. Despite its prevalence, the pathophysiology of FM remains poorly understood, with current treatments often providing limited relief. Recent studies have suggested that metformin, a widely used antidiabetic drug, may have potential therapeutic benefits for chronic pain conditions, including FM. This review aims to provide current insights into the role of metformin in FM pathophysiology, focusing on its neurotransmitter-modulating and anti-inflammatory effects. Metformin has been shown to mitigate neuroinflammation, protect neural tissues, and modulate key neurotransmitters involved in pain and mood regulation. These effects are particularly evident in animal models, where metformin has been observed to reduce pain sensitivity, improve mood-related behaviors, and decrease levels of pro-inflammatory cytokines like interleukin 1-beta (IL-1β). Additionally, the ability of metformin to influence serotonin, norepinephrine, and glutamate levels suggests a potential mechanism for its analgesic and mood-stabilizing effects. However, the current evidence is largely preclinical, and further research is needed to confirm these findings in human studies. This review aims to encourage researchers to explore the association between metformin and FM more deeply, with the hope of uncovering new therapeutic strategies that could offer relief to FM patients.

Proteostasis disruption and senescence in Alzheimer's disease pathways to neurodegeneration

Alzheimer's Disease (AD) is a progressive neurological disease associated with behavioral abnormalities, memory loss, and cognitive impairment that cause major causes of dementia in the elderly. The pathogenetic processes cause complex effects on brain function and AD progression. The proper protein homeostasis, or proteostasis, is critical for cell health. AD causes the buildup of misfolded proteins, particularly tau and amyloid-beta, to break down proteostasis, such aggregates are toxic to neurons and play a critical role in AD pathogenesis. The rise of cellular senescence is accompanied by aging, marked by irreversible cell cycle arrest and the release of pro-inflammatory proteins. Senescent cell build-up in the brains of AD patients exacerbates neuroinflammation and neuronal degeneration. These cells senescence-associated secretory phenotype (SASP) also disturbs the brain environment. When proteostasis failure and cellular senescence coalesce, a cycle is generated that compounds each other. While senescent cells contribute to proteostasis breakdown through inflammatory and degradative processes, misfolded proteins induce cellular stress and senescence. The principal aspects of the neurodegenerative processes in AD are the interaction of cellular senescence and proteostasis failure. This review explores the interconnected roles of proteostasis disruption and cellular senescence in the pathways leading to neurodegeneration in AD.

The mechanisms, hallmarks, and therapies for brain aging and age-related dementia

Age-related cognitive decline and dementia are significant manifestations of brain aging. As the elderly population grows rapidly, the health and socio-economic impacts of cognitive dysfunction have become increasingly significant. Although clinical treatment of dementia has faced considerable challenges over the past few decades, with limited breakthroughs in slowing its progression, there has been substantial progress in understanding the molecular mechanisms and hallmarks of age-related dementia (ARD). This progress brings new hope for the intervention and treatment of this disease. In this review, we categorize the latest findings in ARD biomarkers into four stages based on disease progression: Healthy brain, pre-clinical, mild cognitive impairment, and dementia. We then systematically summarize the most promising therapeutic approaches to prevent or slow ARD at four levels: Genome and epigenome, organelle, cell, and organ and organism. We emphasize the importance of early prevention and detection, along with the implementation of combined treatments as multimodal intervention strategies, to address brain aging and ARD in the future.

The ellagitannin metabolite urolithin C attenuated cognitive impairment by inhibiting neuroinflammation via downregulation of MAPK/NF-kB signaling pathways in aging mice

The current study aimed to evaluate the preventive effects of urolithin C (Uro C), a gut microbial metabolite of ellagitannins on D-galactose (D-gal)-induced brain damage during the aging process and to elucidate the underlying mechanisms. In our study, the protective effect of Uro C on D-gal-induced BV2 microglia cell-mediated neuroinflammation damage in primary cortical neurons in vitro was confirmed. The results in an aging model in vivo induced by D-gal demonstrated that Uro C prevented D-gal-induced memory impairment, long-term potentiation (LTP) damage, and synaptic dysfunction through behavioral, electrophysiological, and histological examinations. Additionally, amyloidogenesis was observed in the central nervous system. The findings indicated that Uro C exhibited a preventive effect on the D-gal-induced elevation of β-amyloid (1-42 specific) (Aβ1-42) accumulation, APP levels, ABCE1 levels, and the equilibrium of the cholinergic system in the aging mouse brain. Moreover, Uro C demonstrated downregulation of D-gal-induced glial overactivation through inhibition of the MAPK/NF-kB pathway. This resulted in the regulation of inflammatory mediators and cytokines, including iNOS, IL-6, IL-1β, and TNF-ɑ, in the mouse brain and BV2 microglial cells. Taken together, our results suggested that Uro C treatment could effectively mitigate the D-gal-induced memory impairment and amyloidogenesis, and the underlying mechanism might be tightly related to the improvement of neuroinflammation by suppressing the MAPK/NF-kB pathway, indicating Uro C might be an alternative and promising agent for the treatment of aging and age-associated brain diseases.

The senotherapeutic potential of phytochemicals for age-related intestinal disease

During the last few decades, life expectancy has increased worldwide along with the prevalence of several age-related diseases. Among aging pathways, cellular senescence and chronic inflammation (or "inflammaging") appear to be connected to gut homeostasis and dysbiosis of the microbiome. Cellular senescence is a state of essentially irreversible cell cycle arrest that occurs in response to stress. Although senescent cells (SC) remain metabolically active, they do not proliferate and can secrete inflammatory and other factors comprising the senescence-associated secretory phenotype (SASP). Accumulation of SCs has been linked to onset of several age-related diseases, in the brain, bones, the gastrointestinal tract, and other organs and tissues. The gut microbiome undergoes substantial changes with aging and is tightly interconnected with either successful (healthy) aging or disease. Senotherapeutic drugs are compounds that can clear senescent cells or modulate the release of SASP factors and hence attenuate the impact of the senescence-associated pro-inflammatory state. Phytochemicals, phenolic compounds and terpenes, which have antioxidant and anti-inflammatory activities, could also be senotherapeutic given their ability to act upon senescence-linked cellular pathways. The aim of this review is to dissect links among the gut microbiome, cellular senescence, inflammaging, and disease, as well as to explore phytochemicals as potential senotherapeutics, focusing on their interactions with gut microbiota. Coordinated targeting of these inter-related processes might unveil new strategies for promoting healthy aging.

Roles of chromatin and genome instability in cellular senescence and their relevance to ageing and related diseases

Ageing is a complex biological process in which a gradual decline in physiological fitness increases susceptibility to diseases such as neurodegenerative disorders and cancer. Cellular senescence, a state of irreversible cell-growth arrest accompanied by functional deterioration, has emerged as a pivotal driver of ageing. In this Review, we discuss how heterochromatin loss, telomere attrition and DNA damage contribute to cellular senescence, ageing and age-related diseases by eliciting genome instability, innate immunity and inflammation. We also discuss how emerging therapeutic strategies could restore heterochromatin stability, maintain telomere integrity and boost the DNA repair capacity, and thus counteract cellular senescence and ageing-associated pathologies. Finally, we outline current research challenges and future directions aimed at better comprehending and delaying ageing.

Gut microbiota and healthy longevity

Recent progress on the underlying biological mechanisms of healthy longevity has propelled the field from elucidating genetic modification of healthy longevity hallmarks to defining mechanisms of gut microbiota influencing it. Importantly, the role of gut microbiota in the healthy longevity of the host may provide unprecedented opportunities to decipher the plasticity of lifespan on a natural evolutionary scale and shed light on using microbiota-targeted strategies to promote healthy aging and combat age-related diseases. This review investigates how gut microbiota affects healthy longevity, focusing on the mechanisms through which gut microbiota modulates it. Specifically, we focused on the ability of gut microbiota to enhance the intestinal barrier integrity, provide protection from inflammaging, ameliorate nutrientsensing pathways, optimize mitochondrial function, and improve defense against age-related diseases, thus participating in enhancing longevity and healthspan.

Geroprotective effects of GdVO4:Eu3 + nanoparticles, metformin and calorie restriction in male rats with accelerated aging induced by overnutrition in early postnatal ontogenesis

GdVO4:Eu3+ nanoparticles (OVNPs) have previously been shown to exhibit anti-aging effects in old rats.The accelerated aging model (overnutrition in early postnatal ontogenesis (POF)) was used to confirm the effect of OVNPs as a potential geroprotector. A comparative study of the effect of OVNPs, calorierestriction (CR) and CR-mimetic-metformin was carried out using a number of criteria: survival, prooxidant-antioxidant balance in the liver and blood, physiological parameters of male Wistar rats with accelerated aging. It was found that the survival of rats with POF was lower than that of control animals.It was found that the rate of superoxide radical formation and the content of lipid hydroperoxides in the mitochondria and microsomes of the liver and blood serum of rats with POF were higher, and the activities of glutathione peroxidases and the GSH content were significantly lower than in the control animals.It was also found that POF leads to perturbation of physiological parameters (body weight, liver weight, liver mass coefficient, body temperature and blood thyroxine concentration) characterizing the quality of life. Long-term use of OVNPs, CR or metformin in rats with accelerated aging normalized the imbalance of the prooxidant-antioxidant system, improved the physiological parameters, and increased the survival of these experimental animals. Moreover, the increase in survival was most pronounced with the use of CR and OVNPs. Considering our results andthe inadmissibility of long-term use of CR, it should be concluded that GdVO4:Eu3+ nanoparticles are promising for the development of agents that slow down the accelerated aging of an organism.

Mitochondrial calcium uptake declines during aging and is directly activated by oleuropein to boost energy metabolism and skeletal muscle performance

Mitochondrial calcium (mtCa2+) uptake via the mitochondrial calcium uniporter (MCU) couples calcium homeostasis and energy metabolism. mtCa2+ uptake via MCU is rate-limiting for mitochondrial activation during muscle contraction, but its pathophysiological role and therapeutic application remain largely uncharacterized. By profiling human muscle biopsies, patient-derived myotubes, and preclinical models, we discovered a conserved downregulation of mitochondrial calcium uniporter regulator 1 (MCUR1) during skeletal muscle aging that associates with human sarcopenia and impairs mtCa2+ uptake and mitochondrial respiration. Through a screen of 5,000 bioactive molecules, we identify the natural polyphenol oleuropein as a specific MCU activator that stimulates mitochondrial respiration via mitochondrial calcium uptake 1 (MICU1) binding. Oleuropein activates mtCa2+ uptake and energy metabolism to enhance endurance and reduce fatigue in young and aged mice but not in muscle-specific MCU knockout (KO) mice. Our work demonstrates that impaired mtCa2+ uptake contributes to mitochondrial dysfunction during aging and establishes oleuropein as a novel food-derived molecule that specifically targets MCU to stimulate mitochondrial bioenergetics and muscle performance.

Photothermal Nano-Immunotherapy Against Methicillin-Resistant Staphylococcus aureus (MRSA) Biofilm Infections

Methicillin-resistant Staphylococcus aureus (MRSA) biofilm infections are a prevalent type of biofilm-associated infection with a poor prognosis and antibiotic resistance. The senescence of immune cells in the immune microenvironment contributes to biofilm formation. In this study, Ti₃C₂ MXene-PVA nanosheets loaded with metformin (Met@TiC) are developed for the treatment of MRSA biofilm infections. Nanosheets utilize near-infrared light to induce photothermal effects and provide direct bactericidal activity against biofilm structures. Met, which is known for its anti-inflammatory and anti-senescence properties, modulates immune responses by revitalizing the function of senescent macrophages within the biofilm microenvironment, thereby enhancing their phagocytic and biofilm-eradicating capabilities. The efficacy of this nanoplatform both in vitro and in an MRSA biofilm infection mouse model, demonstrating its potential as a photothermal nanoimmunotherapy for combating MRSA biofilm infections is validated. In summary, the Met@TiC nanoplatform offers a significant alternative to clinical solutions for MRSA biofilm infections.

The Epistemic Policies of Anti-Ageing Medicines in the European Union

Anti-ageing medicines are products intended to extend lifespan and healthspan in humans that have a good potential use in public health policies. In the European Union, their development, production and consumption are dependent on regulatory science performed by the European Medicines Agency and its associated epistemic policies. They impose, among other things, an unfavourable burden of proof, a strict standard of proof and meta-methodological constrictions related to some theoretical issues. This results in a distribution of errors that tends to reduce false positives while increasing false negatives, leading to a set of social consequences that are generally accepted when the focus is placed on conventional medicines. However, when the same epistemic policies are applied to anti-ageing medicines, the distribution of errors is imbalanced, and undesirable outcomes like research discouragement and waiting time extensions appear. Three possible strategies that policymakers could implement to unblock the situation are presented for future reflection: the consideration of ageing as a disease, the application of methodological asymmetry and the use of biomarkers during clinical research.

Modeling of TDP-43 proteinopathy by chronic oxidative stress identifies rapamycin as beneficial in ALS patient-derived 2D and 3D iPSC models

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disorder characterized neuropathologically by TDP-43 proteinopathy with loss of TDP-43 nuclear splicing activity and formation of cytoplasmic TDP-43 aggregates. The lack of suitable experimental models of TDP-43 proteinopathy has hampered the discovery of effective therapies. We already showed that chronic and mild oxidative insult by sodium arsenite (ARS) triggered TDP-43 cytoplasmic aggregation and stress granules (SGs) formation in ALS patient-derived fibroblasts and motor neurons differentiated from induced pluripotent stem cells (iPSC-MNs). However, whether this insult induces a reduction of TDP-43 splicing activity in the nucleus, thus recapitulating both gain and loss of function pathomechanisms, still remains to be determined. In this study we first showed that chronic ARS in human neuroblastoma cells triggered TDP-43 cytoplasmic mislocalization, SGs formation and defective splicing of TDP-43 target genes UNC13A and POLDIP3 as functional readouts of TDP-43 proteinopathy. Additionally, a dysregulation of autophagy and senescence markers was observed in this condition. In a preliminary drug screening approach with autophagy-promoting drugs, namely rapamycin, lithium carbonate and metformin, only rapamycin prevented ARS-induced loss of TDP-43 splicing activity. We then demonstrated that, in addition to TDP-43 cytoplasmic aggregation, chronic ARS triggered TDP-43 loss of splicing activity also in ALS patient-derived primary fibroblasts and iPSC-MNs and that rapamycin was beneficial to reduce these TDP-43 pathological features. By switching to a neuro-glial 3D in vitro model, we observed that treatment of ALS iPSC-brain organoids with chronic ARS also induced a defective TDP-43 splicing activity which was prevented by rapamycin. Collectively, we established different human cell models of TDP-43 proteinopathy which recapitulate TDP-43 gain and loss of function, prevented by rapamycin administration. Human neuroblastoma cells and patient-derived fibroblasts and 2D- and 3D-iPSC models exposed to chronic oxidative stress represent therefore suitable in vitro platforms for future drug screening approaches in ALS.

The Quest for Eternal Youth: Hallmarks of Aging and Rejuvenating Therapeutic Strategies

The impressive achievements made in the last century in extending the lifespan have led to a significant growth rate of elderly individuals in populations across the world and an exponential increase in the incidence of age-related conditions such as cardiovascular diseases, diabetes mellitus type 2, and neurodegenerative diseases. To date, geroscientists have identified 12 hallmarks of aging (genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, impaired macroautophagy, mitochondrial dysfunction, impaired nutrient sensing, cellular senescence, stem cell exhaustion, defective intercellular communication, chronic inflammation, and gut dysbiosis), intricately linked among each other, which can be targeted with senolytic or senomorphic drugs, as well as with more aggressive approaches such as cell-based therapies. To date, side effects seriously limit the use of these drugs. However, since rejuvenation is a dream of mankind, future research is expected to improve the tolerability of the available drugs and highlight novel strategies. In the meantime, the medical community, healthcare providers, and society should decide when to start these treatments and how to tailor them individually.

Autophagy in Muscle Regeneration: Mechanisms, Targets, and Therapeutic Perspective

Autophagy maintains the stability of eukaryotic cells by degrading unwanted components and recycling nutrients and plays a pivotal role in muscle regeneration by regulating the quiescence, activation, and differentiation of satellite cells. Effective muscle regeneration is vital for maintaining muscle health and homeostasis. However, under certain disease conditions, such as aging, muscle regeneration can fail due to dysfunctional satellite cells. Dysregulated autophagy may limit satellite cell self-renewal, hinder differentiation, and increase susceptibility to apoptosis, thereby impeding muscle regeneration. This review explores the critical role of autophagy in muscle regeneration, emphasizing its interplay with apoptosis and recent advances in autophagy research related to diseases characterized by impaired muscle regeneration. Additionally, we discuss new approaches involving autophagy regulation to promote macrophage polarization, enhancing muscle regeneration. We suggest that utilizing cell therapy and biomaterials to modulate autophagy could be a promising strategy for supporting muscle regeneration. We hope that this review will provide new insights into the treatment of muscle diseases and promote muscle regeneration.

Inflammation unites diverse acute and chronic diseases

BACKGROUND

Inflammation and immunity contribute pivotally to diverse acute and chronic diseases. Inflammatory pathways have become increasingly targets for therapy. Yet, despite substantial similarity in mechanisms and pathways, the scientific, medical, pharma and biotechnology sectors have generally focused programs finely on a single disease entity or organ system. This insularity may impede progress in innovation and the harnessing of powerful new insights into inflammation biology ripe for clinical translation.

METHODS

A multidisciplinary thinktank reviewed highlights how inflammation contributes to diverse diseases, disturbed homeostasis, ageing and impaired healthspan. We explored how common inflammatory and immune mechanisms that operate in key conditions in their respective domains. This consensus review highlights the high degree of commonality of inflammatory mechanisms in a diverse array of conditions that together contribute a major part of the global burden of morbidity and mortality and present an enormous challenge to public health and drain on resources.

RESULTS

We demonstrate how that shared inflammatory mechanisms unite many seemingly disparate diseases, both acute and chronic. The examples of infection, cardiovascular conditions, pulmonary diseases, rheumatological disorders, dementia, cancer and ageing illustrate the overlapping pathogenesis. We outline opportunities to synergize, reduce duplication and consolidate efforts of the clinical, research and pharmaceutical communities. Enhanced recognition of these commonalties should promote cross-fertilization and hasten progress in this rapidly moving domain.

CONCLUSIONS

Greater appreciation of the shared mechanisms should simplify understanding seemingly disparate diseases for clinicians and help them to recognize inflammation as a therapeutic target which the development of novel therapies is rendering actionable.

TNFSF14+ natural killer cells prevent spontaneous abortion by restricting leucine-mediated decidual stromal cell senescence

In preparation for a potential pregnancy, the endometrium of the uterus changes into a temporary structure called the decidua. Senescent decidual stromal cells (DSCs) are enriched in the decidua during decidualization, but the underlying mechanisms of this process remain unclear. Here, we performed single-cell RNA transcriptomics on ESCs and DSCs and found that cell senescence during decidualization is accompanied by increased levels of the branched-chain amino acid (BCAA) transporter SLC3A2. Depletion of leucine, one of the branched-chain amino acids, from cultured media decreased senescence, while high leucine diet resulted in increased senescence and high rates of embryo loss in mice. BCAAs induced senescence in DSCs via the p38 MAPK pathway. In contrast, TNFSF14+ decidual natural killer (dNK) cells were found to inhibit DSC senescence by interacting with its ligand TNFRSF14. As in mice fed high-leucine diets, both mice with NK cell depletion and Tnfrsf14-deficient mice with excessive uterine senescence experienced adverse pregnancy outcomes. Further, we found excessive uterine senescence, SLC3A2-mediated BCAA intake, and insufficient TNFRSF14 expression in the decidua of patients with recurrent spontaneous abortion. In summary, this study suggests that dNK cells maintain senescence homeostasis of DSCs via TNFSF14/TNFRSF14, providing a potential therapeutic strategy to prevent DSC senescence-associated spontaneous abortion.

The impact of short-lived controls on the interpretation of lifespan experiments and progress in geroscience - Through the lens of the "900-day rule"

Although lifespan extension remains the gold standard for assessing interventions proposed to impact the biology of aging, there are important limitations to this approach. Our reanalysis of lifespan studies from multiple sources suggests that short lifespans in the control group exaggerate the relative efficacy of putative longevity interventions. Results may be exaggerated due to statistical effects (e.g. regression to the mean) or other factors. Moreover, due to the high cost and long timeframes of mouse studies, it is rare that a particular longevity intervention will be independently replicated by multiple groups. To facilitate identification of successful interventions, we propose an alternative approach particularly suitable for well-characterized inbred and HET3 mice. In our opinion, the level of confidence we can have in an intervention is proportional to the degree of lifespan extension above the strain- and species-specific upper limit of lifespan, which we can estimate from comparison to historical controls. In the absence of independent replication, a putative mouse longevity intervention should only be considered with high confidence when control median lifespans are close to 900 days or if the final lifespan of the treated group is considerably above 900 days. Using this "900-day rule" we identified several candidate interventions from the literature that merit follow-up studies.

The Health Costs of Cost Sharing

What happens when patients suddenly stop their medications? We study the health consequences of drug interruptions caused by large, abrupt, and arbitrary changes in price. Medicare's prescription drug benefit as-if-randomly assigns 65-year-olds a drug budget as a function of their birth month, beyond which out-of-pocket costs suddenly increase. Those facing smaller budgets consume fewer drugs and die more: mortality increases 0.0164 percentage points per month (13.9%) for each $100 per month budget decrease (24.4%). This estimate is robust to a range of falsification checks and lies in the 97.8th percentile of 544 placebo estimates from similar populations that lack the same idiosyncratic budget policy. Several facts help make sense of this large effect. First, patients stop taking drugs that are both high value and suspected to cause life-threatening withdrawal syndromes when stopped. Second, using machine learning, we identify patients at the highest risk of drug-preventable adverse events. Contrary to the predictions of standard economic models, high-risk patients (e.g., those most likely to have a heart attack) cut back more than low-risk patients on exactly those drugs that would benefit them the most (e.g., statins). Finally, patients appear unaware of these risks. In a survey of 65-year-olds, only one-third believe that stopping their drugs for up to a month could have any serious consequences. We conclude that far from curbing waste, cost sharing is itself highly inefficient, resulting in missed opportunities to buy health at very low cost ($11,321 per life-year).

Targeting senescent cells in atherosclerosis: Pathways to novel therapies

Targeting senescent cells has recently emerged as a promising strategy for treating age-related diseases, such as atherosclerosis, which significantly contributes to global cardiovascular morbidity and mortality. This review elucidates the role of senescent cells in the development of atherosclerosis, including persistently damaging DNA, inducing oxidative stress and secreting pro-inflammatory factors known as the senescence-associated secretory phenotype. Therapeutic approaches targeting senescent cells to mitigate atherosclerosis are summarized in this review, which include the development of senotherapeutics and immunotherapies. These therapies are designed to either remove these cells or suppress their deleterious effects. These emerging therapies hold potential to decelerate or even alleviate the progression of AS, paving the way for new avenues in cardiovascular research and treatment.

Metformin restores autophagic flux and mitochondrial function in late passage myoblast to impede age-related muscle loss

Sarcopenia, which refers to age-related muscle loss, presents a significant challenge for the aging population. Age-related changes that contribute to sarcopenia include cellular senescence, decreased muscle stem cell number and regenerative capacity, impaired autophagy, and mitochondrial dysfunction. Metformin, an anti-diabetic agent, activates AMP-activated protein kinase (AMPK) and affects various cellular processes in addition to reducing hepatic gluconeogenesis, lowering blood glucose levels, and improving insulin resistance. However, its effect on skeletal muscle cells remains unclear. This study aimed to investigate the effects of metformin on age-related muscle loss using a late passage C2C12 cell model. The results demonstrated that metformin alleviated hallmarks of cellular senescence, including SA-β-gal activity and p21 overexpression. Moreover, treatment with pharmacological concentrations of metformin restored the reduced differentiation capacity in late passage cells, evident through increased myotube formation ability and enhanced expression of myogenic differentiation markers such as MyoD, MyoG, and MHC. These effects of metformin were attributed to enhanced autophagic activity, normalization of mitochondrial membrane potential, and improved mitochondrial respiratory capacity. These results suggest that pharmacological concentrations of metformin alleviate the hallmarks of cellular senescence, restore differentiation capacity, and improve autophagic flux and mitochondrial function. These findings support the potential use of metformin for the treatment of sarcopenia.

Immune therapeutic strategies for the senescent tumor microenvironment

Senescent cells can either to promote immunosuppressive tumor microenvironment or facilitate immune surveillance. Despite the revolutionary impact of cancer immunotherapy, durable responses in solid tumors, particularly in advanced stages, remain limited. Recent studies have shed light on the influence of senescent status within the tumor microenvironment (TME) on therapy resistance and major efforts are needed to overcome these challenges. This review summarizes recent advancements in targeting cellular senescence, with a particular focus on immunomodulatory approaches on the hallmarks of cellular senescence.

Cell senescence in cardiometabolic diseases

Cellular senescence has been implicated in many age-related pathologies including atherosclerosis, heart failure, age-related cardiac remodeling, diabetic cardiomyopathy and the metabolic syndrome. Here, we will review the characteristics of senescent cells and their endogenous regulators, and summarize the metabolic stressors that induce cell senescence. We will discuss the evidence of cell senescence in the onset and progression of several cardiometabolic diseases and the therapeutic potential of anti-senescence therapies.

Unraveling aging from transcriptomics

Research into aging constitutes a pivotal endeavor aimed at elucidating the underlying biological mechanisms governing aging and age-associated diseases, as well as promoting healthy longevity. Recent advances in transcriptomic technologies, such as bulk RNA sequencing (RNA-seq), single-cell transcriptomics, and spatial transcriptomics, have revolutionized our ability to study aging at unprecedented resolution and scale. These technologies present novel opportunities for the discovery of biomarkers, elucidation of molecular pathways, and development of targeted therapeutic strategies for age-related disorders. This review surveys recent breakthroughs in different types of transcripts on aging, such as mRNA, long noncoding (lnc)RNA, tRNA, and miRNA, highlighting key findings and discussing their potential implications for future studies in this field.

Gut aging: A wane from the normal to repercussion and gerotherapeutic strategies

Globally, age-related diseases represent a significant public health concern among the elderly population. In aging, healthy organs and tissues undergo structural and functional changes that put the aged adults at risk of diseases. Some of the age-related diseases include cancer, atherosclerosis, brain disorders, muscle atrophy (sarcopenia), gastrointestinal (GIT) disorders, etc. In organs, a decline in stem cell function is the starting point of many conditions and is extremely important in GIT disorder development. Many studies have established that aging affects stem cells and their surrounding supportive niche components. Although there is a significant advancement in treating intestinal aging, the rising elderly population coupled with a higher occurrence of chronic gut ailments necessitates more effective therapeutic approaches to preserve gut health. Notable therapeutic strategies such as Western medicine, traditional Chinese medicine, and other health-promotion interventions have been reported in several studies to hold promise in mitigating age-related gut disorders. This review highlights findings across various facets of gut aging with a focus on aging-associated changes of intestinal stem cells and their niche components, thus a deviation from the normal to repercussion, as well as essential therapeutic strategies to mitigate intestinal aging.

Aging in chronic lung disease: Will anti-aging therapy be the key to the cure?

Chronic lung disease is the third leading cause of death globally, imposing huge burden of death, disability and healthcare costs. However, traditional pharmacotherapy has relatively limited effects in improving the cure rate and reducing the mortality of chronic lung disease. Thus, new treatments are urgently needed for the prevention and treatment of chronic lung disease. It is particularly noteworthy that, multiple aging-related phenotypes were involved in the occurrence and development of chronic lung disease, such as blocked proliferation, telomere attrition, mitochondrial dysfunction, epigenetic alterations, altered nutrient perception, stem cell exhaustion, chronic inflammation, etc. Consequently, senescent cells induce a series of pathological changes in the lung, such as immune dysfunction, airway remodeling, oxidative stress and regenerative dysfunction, which is a critical issue that needs special attention in chronic lung diseases. Therefore, anti-aging interventions may bring new insights into the treatment of chronic lung diseases. In this review, we elaborate the involvement of aging in chronic lung disease and further discuss the application and prospects of anti-aging therapy.

Quantitative NMR Analysis of Marine Macroalgae for AGE Inhibition by Methylglyoxal Scavenging

Reactive carbonyl species (RCS) induce a fundamental form of biological stress that has driven the evolution of diverse mechanisms for minimizing its impact on organismal health. The complications that accompany uncontrolled hyperglycemia exemplify the health implications when RCS stress exceeds the body's capacity to prevent the excessive formation of advanced glycation end-products. Presented here is a novel quantitative NMR (qNMR) technique for evaluating scavengers of the prominent sugar-derived carbonyl methylglyoxal (MGO). This tool was employed to screen the chemical diversity of marine macroalgae extracts, with a focus on species that have a history of consumption by the World's healthiest populations and are subject to global scale aquacultural production. Fucus vesiculosus demonstrated the highest capacity for inhibiting glycation and scavenging MGO. Additionally, the Chondrus cripsus, Gracilaria vermiculophyla, and Gracilaria tikvahiae extracts had a high capacity for scavenging MGO, representing the first report of this activity. This new qNMR methodology presented is highly applicable for screening extracts and compounds from diverse sources, and the results highlight the potential of macroalgae extracts to be employed as RCS and AGE targeting therapeutics and food additives.

Sedentary Lifestyles and a Hypercaloric Diets During Middle Age, are Binomial Conducive to Fatal Progression, That is Counteracted by the Hormetic Treatment of Exercise, Metformin, and Tert-Butyl Hydroquinone: An Analysis of Female Middle-Aged Rat Liver Mitochondria

The world's population continuous to shift towards older, less active and more sedentary lifestyles especially during middle age. In addition consumption of high-caloric diets, increases the risk of metabolic and cardiovascular afflictions. Developing clinical strategies to mitigate those health complications represent a difficult challenge. Our group has previously shown that combining metformin (MTF) and tert-butyl hydroquinone (tBHQ) treatments, in addition to exercise, partially prevents liver damage associated with obesity. Hence, we evaluated the role of exercise in combination with MTF and tBHQ (triple-treatment) to counteract mitochondrial damage in the liver from obese middle-aged female rats. Animals were fed a high-fat diet (HFD) starting at 21 days till 15 months of age. The treated groups performed a Fartlek-type exercise 5 days/week for 30 min/session. MTF and tBHQ were administered at a dose of 250 mg/kg/day, and 10 mg/kg/day, respectively, for 7 days/month from 10 to 15 months of age. Triple-treatment therapeutic approach promoted animal survival, and increased AMPK and PGC1α expression. Treatments increased mitochondrial ATP synthesis and OXPHOS complexes activities, recovered membrane potential, and decreased ROS production. In summary, exercise in combination with intermittent tBHQ and MTF treatments proved to be an excellent intervention to prevent mitochondrial damage caused by HFD.

Targeting organ-specific mitochondrial dysfunction to improve biological aging

In an aging society, unveiling new anti-aging strategies to prevent and combat aging-related diseases is of utmost importance. Mitochondria are the primary ATP production sites and key regulators of programmed cell death. Consequently, these highly dynamic organelles play a central role in maintaining tissue function, and mitochondrial dysfunction is a pivotal factor in the progressive age-related decline in cellular homeostasis and organ function. The current review examines recent advances in understanding the interplay between mitochondrial dysfunction and organ-specific aging. Thereby, we dissect molecular mechanisms underlying mitochondrial impairment associated with the deterioration of organ function, exploring the role of mitochondrial DNA, reactive oxygen species homeostasis, metabolic activity, damage-associated molecular patterns, biogenesis, turnover, and dynamics. We also highlight emerging therapeutic strategies in preclinical and clinical tests that are supposed to rejuvenate mitochondrial function, such as antioxidants, mitochondrial biogenesis stimulators, and modulators of mitochondrial turnover and dynamics. Furthermore, we discuss potential benefits and challenges associated with the use of these interventions, emphasizing the need for organ-specific approaches given the unique mitochondrial characteristics of different tissues. In conclusion, this review highlights the therapeutic potential of addressing mitochondrial dysfunction to mitigate organ-specific aging, focusing on the skin, liver, lung, brain, skeletal muscle, and lung, as well as on the reproductive, immune, and cardiovascular systems. Based on a comprehensive understanding of the multifaceted roles of mitochondria, innovative therapeutic strategies may be developed and optimized to combat biological aging and promote healthy aging across diverse organ systems.

Metformin facilitates viral reservoir reactivation and their recognition by anti-HIV-1 envelope antibodies

The mechanistic target of rapamycin (mTOR) positively regulates multiple steps of the HIV-1 replication cycle. We previously reported that a 12-week supplementation of antiretroviral therapy (ART) with metformin, an indirect mTOR inhibitor used in type-2 diabetes treatment, reduced mTOR activation and HIV transcription in colon-infiltrating CD4+ T cells, together with systemic inflammation in nondiabetic people with HIV-1 (PWH). Herein, we investigated the antiviral mechanisms of metformin. In a viral outgrowth assay performed with CD4+ T cells from ART-treated PWH, and upon infection in vitro with replication-competent and VSV-G-pseudotyped HIV-1, metformin decreased virion release, but increased the frequency of productively infected CD4lowHIV-p24+ T cells. These observations coincided with increased BST2/tetherin (HIV release inhibitor) and Bcl-2 (pro-survival factor) expression, and improved recognition of productively infected T cells by HIV-1 envelope antibodies. Thus, metformin exerts pleiotropic effects on post-integration steps of the HIV-1 replication cycle and may be used to accelerate viral reservoir decay in ART-treated PWH.

The direct targets of metformin in diabetes and beyond

Metformin, an oral antihyperglycemic drug that has been in use for over 60 years, remains a first-line therapy for type 2 diabetes (T2D). Numerous studies have suggested that metformin promotes health benefits beyond T2D management, including weight loss, cancer prevention and treatment, and anti-aging, through several proposed mechanistic targets. Here we discuss the established effects of metformin and the progress made in identifying its direct targets. Additionally, we emphasize the importance of elucidating the structural bases of the drug and its direct targets. Ultimately, this review aims to highlight the current state of knowledge regarding metformin and its related emerging discoveries, while also outlining critical future research directions.

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.

Metformin modulates mitochondrial autophagy in renal tubular epithelial injury induced by high glucose via the Keap1/Nrf2 pathway

The current study aimed to explore the role and underpinning molecular mechanisms of metformin in renal cellular injury induced by high glucose levels. Male C57BL/KsJ (db/db) and (db/m +) mice were utilized in this study. The experimental group was administered 1 mg/mL of metformin through drinking water. Renal tissues were harvested for hematoxylin and eosin (HE) staining, superoxide dismutase (SOD) activity detection, biochemical indices analysis, Western blotting, and qRT-PCR. HK-2 cells were utilized for Nrf2 siRNA transfection and to establish a high level of glucose-induced cell models. Metformin was administered at a concentration of 1 mmol/L in the experimental group. Cellular viability was assessed using CCK-8, whereas acridine orange (AO) staining and LC3-mitotracker co-localization staining were employed to evaluate autophagy. The expression of Nrf2, P21, LC3, PTEN-induced putative kinase 1 (PINK1), translocase of outer mitochondrial membrane 20 (TOMM20), and Kelch-like ECH-associated protein 1 (Keap1) were determined through Western blotting and qRT-PCR. Metformin mitigated renal tissue inflammatory damage in diabetic mice, as indicated by upregulated expression of Nrf2, PINK1, LC3, and TOMM20, and downregulated expression of Keap1 and P21. High level of glucose treatment in HK-2 cells resulted in decreased autophagy, and reduced expression of Nrf2, PINK1, LC3, and TOMM20 alongside elevated the expression of Keap1 and P21. Notably, metformin treatment partially counteracted these effects. Nrf2 knockdown intensified these phenomena in the high level of glucose-induced model. Protein-protein interaction network analysis indicated that Nrf2 could regulate the majority autophagy-related proteins via Keap1. Metformin modulates mitochondrial autophagy in high glucose-induced renal tubular epithelial senescence via the Keap1/Nrf2 pathway.

Telomere stabilization by metformin mitigates the progression of atherosclerosis via the AMPK-dependent p-PGC-1α pathway

Telomere dysfunction is a well-known molecular trigger of senescence and has been associated with various age-related diseases, including atherosclerosis. However, the mechanisms involved have not yet been elucidated, and the extent to which telomeres contribute to atherosclerosis is unknown. Therefore, we investigated the mechanism of metformin-induced telomere stabilization and the ability of metformin to inhibit vascular smooth muscle cell (VSMC) senescence caused by advanced atherosclerosis. The present study revealed that metformin inhibited the phenotypes of atherosclerosis and senescence in VSMCs. Metformin increased the phosphorylation of AMPK-dependent PGC-1α and thus increased telomerase activity and the protein level of TERT in OA-treated VSMCs. Mechanistically, the phosphorylation of AMPK and PGC-1α by metformin not only enhanced telomere function but also increased the protein level of TERT, whereas TERT knockdown accelerated the development of atherosclerosis and senescent phenotypes in OA-treated VSMCs regardless of metformin treatment. Furthermore, the in vivo results showed that metformin attenuated the formation of atherosclerotic plaque markers in the aortas of HFD-fed ApoE KO mice. Although metformin did not reduce plaque size, it inhibited the phosphorylation of the AMPK/PGC-1α/TERT signaling cascade, which is associated with the maintenance and progression of plaque formation, in HFD-fed ApoE KO mice. Accordingly, metformin inhibited atherosclerosis-associated phenotypes in vitro and in vivo. These observations show that the enhancement of telomere function by metformin is involved in specific signaling pathways during the progression of atherosclerosis. These findings suggest that telomere stabilization by metformin via the AMPK/p-PGC-1α pathway might provide a strategy for developing therapeutics against vascular diseases such as atherosclerosis.

Hypothalamic circuits and aging: keeping the circadian clock updated

Over the past century, age-related diseases, such as cancer, type-2 diabetes, obesity, and mental illness, have shown a significant increase, negatively impacting overall quality of life. Studies on aged animal models have unveiled a progressive discoordination at multiple regulatory levels, including transcriptional, translational, and post-translational processes, resulting from cellular stress and circadian derangements. The circadian clock emerges as a key regulator, sustaining physiological homeostasis and promoting healthy aging through timely molecular coordination of pivotal cellular processes, such as stem-cell function, cellular stress responses, and inter-tissue communication, which become disrupted during aging. Given the crucial role of hypothalamic circuits in regulating organismal physiology, metabolic control, sleep homeostasis, and circadian rhythms, and their dependence on these processes, strategies aimed at enhancing hypothalamic and circadian function, including pharmacological and non-pharmacological approaches, offer systemic benefits for healthy aging. Intranasal brain-directed drug administration represents a promising avenue for effectively targeting specific brain regions, like the hypothalamus, while reducing side effects associated with systemic drug delivery, thereby presenting new therapeutic possibilities for diverse age-related conditions.

A Pragmatic Approach to Introducing Translational Geroscience Into the Clinic: A Paradigm Based on the Incremental Progression of Aging-Related Clinical Research

Geroscience posits that molecular drivers underlie the aging process. Gerotherapeutics entail strategies to counter molecular drivers of aging to reduce the chronic diseases and geriatric syndromes they trigger. Although the concept of gerotherapeutics for prevention has generated much excitement, the implications of prescribing potentially harmful medications to older adults who are "healthy" have been associated with many delays. Concerns regarding safety and valid endpoints have contributed to holdups. In contrast, it has been relatively easier to implement trials of medications with gerotherapeutic properties as novel approaches to remedy disease. In these applications, the risks of the medications are easier to justify when therapeutic benefits are perceived as outweighing the harms of the disease. Likewise, metrics of effective disease treatments are often seen as more reliable and quantifiable than metrics of health prolongation. Overall, clarifying geroscience mechanisms in disease therapeutic applications provides key opportunities to advance translational geroscience, especially as preventive geroscience trials are often encumbered. In this review, gerotherapeutic benefits of canakinumab, cholchicine, and zoledronic acid as parts of disease management are considered. Longevity Clinics and other opportunities to advance translational geroscience as parts of contemporary care are also discussed.

Transplantation of astrocyte-derived mitochondria into injured astrocytes has a protective effect following stretch injury

Traumatic brain injury (TBI) is a global public-health problem. Astrocytes, and their mitochondria, are important factors in the pathogenesis of TBI-induced secondary injury. Mitochondria extracted from healthy tissues and then transplanted have shown promise in models of a variety of diseases. However, the effect on recipient astrocytes is unclear. Here, we isolated primary astrocytes from newborn C57BL/6 mice, one portion of which was used to isolate mitochondria, and another was subjected to stretch injury (SI) followed by transplantation of the isolated mitochondria. After incubation for 12 h, cell viability, mitochondrial dysfunction, calcium overload, redox stress, inflammatory response, and apoptosis were improved. Live-cell imaging showed that the transplanted mitochondria were incorporated into injured astrocytes and fused with their mitochondrial networks, which was in accordance with the changes in the expression levels of markers of mitochondrial dynamics. The astrocytic IKK/NF-κB pathway was decelerated whereas the AMPK/PGC-1α pathway was accelerated by transplantation. Together, these results indicate that exogenous mitochondria from untreated astrocytes can be incorporated into injured astrocytes and fuse with their mitochondrial networks, improving cell viability by ameliorating mitochondrial dysfunction, redox stress, calcium overload, and inflammation.

Metformin and its potential influence on cell fate decision between apoptosis and senescence in cancer, with a special emphasis on glioblastoma

Despite reaching enormous achievements in therapeutic approaches worldwide, GBM still remains the most incurable malignancy among various cancers. It emphasizes the necessity of adjuvant therapies from the perspectives of both patients and healthcare providers. Therefore, most emerging studies have focused on various complementary and adjuvant therapies. Among them, metabolic therapy has received special attention, and metformin has been considered as a treatment in various types of cancer, including GBM. It is clearly evident that reaching efficient approaches without a comprehensive evaluation of the key mechanisms is not possible. Among the studied mechanisms, one of the more challenging ones is the effect of metformin on apoptosis and senescence. Moreover, metformin is well known as an insulin sensitizer. However, if insulin signaling is facilitated in the tumor microenvironment, it may result in tumor growth. Therefore, to partially resolve some paradoxical issues, we conducted a narrative review of related studies to address the following questions as comprehensively as possible: 1) Does the improvement of cellular insulin function resulting from metformin have detrimental or beneficial effects on GBM cells? 2) If these effects are detrimental to GBM cells, which is more important: apoptosis or senescence? 3) What determines the cellular decision between apoptosis and senescence?

The impact of metformin on mortality in patients with type 2 diabetes mellitus: a prospective cohort study

BACKGROUND

Metformin, a widely used antihyperglycemic drug, has shown efficacy in treating type 2 diabetes mellitus (T2DM) and is associated with potential benefits beyond glycemic control. This study investigates the impact of metformin on mortality in T2DM patients using a prospective cohort design utilizing data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

In NHANES 1999-2014, a total of 5813 representative participants aged 20 and above with T2DM were included in the analysis. We utilized Kaplan-Meier survival curves and multivariate Cox regression analysis to investigate the impact of metformin on both all-cause mortality and cause-specific mortality among patients with T2DM.

RESULTS

Kaplan-Meier analysis showed a significant reduction in all-cause and cause-specific mortality in metformin users compared to non-users (p < 0.05). Multivariate Cox regression confirmed these findings, indicating that metformin use was associated with a 18% reduction in all-cause mortality (HR = 0.82, 95% CI = 0.73-0.92, p < 0.001) and 25% reduction in cardiovascular mortality (HR = 0.75, 95% CI = 0.60-0.94, p = 0.01).

CONCLUSION

Our results suggest that metformin significantly reduces all-cause and cardiovascular mortality in T2DM patients, highlighting its potential benefits beyond glycemic control. These results contribute to the existing literature by providing robust evidence from a large prospective cohort study. However, further research is needed to validate these findings and elucidate the underlying mechanisms controlling the effects of metformin on mortality outcomes in individuals with T2DM.

Cellular Senescence: The Driving Force of Musculoskeletal Diseases

The aging of the world population is closely associated with an increased prevalence of musculoskeletal disorders, such as osteoporosis, sarcopenia, and osteoarthritis, due to common genetic, endocrine, and mechanical risk factors. These conditions are characterized by degeneration of bone, muscle, and cartilage tissue, resulting in an increased risk of fractures and reduced mobility. Importantly, a crucial role in the pathophysiology of these diseases has been proposed for cellular senescence, a state of irreversible cell cycle arrest induced by factors such as DNA damage, telomere shortening, and mitochondrial dysfunction. In addition, senescent cells secrete pro-inflammatory molecules, called senescence-associated secretory phenotype (SASP), which can alter tissue homeostasis and promote disease progression. Undoubtedly, targeting senescent cells and their secretory profiles could promote the development of integrated strategies, including regular exercise and a balanced diet or the use of senolytics and senomorphs, to improve the quality of life of the aging population. Therefore, our review aimed to highlight the role of cellular senescence in age-related musculoskeletal diseases, summarizing the main underlying mechanisms and potential anti-senescence strategies for the treatment of osteoporosis, sarcopenia, and osteoarthritis.

METFORMIN: FROM DIABETES TO CANCER TO PROLONGATION OF LIFE

The metformin molecule dates back to over a century, but its clinical use started in the '50s. Since then, its use in diabetics has grown constantly, with over 150 million users today. The therapeutic profile also expanded, with improved understanding of novel mechanisms. Metformin has a major activity on insulin resistance, by acting on the insulin receptors and mitochondria, most likely by activation of the adenosine monophosphate-activated kinase. These and associated mechanisms lead to significant lipid lowering and body weight loss. An anti-cancer action has come up in recent years, with mechanisms partly dependent on the mitochondrial activity and also on phosphatidylinositol 3-kinase resistance occurring in some malignant tumors. The potential of metformin to raise life-length is the object of large ongoing studies and of several basic and clinical investigations. The present review article will attempt to investigate the basic mechanisms behind these diverse activities and the potential clinical benefits. Metformin may act on transcriptional activity by histone modification, DNA methylation and miRNAs. An activity on age-associated inflammation (inflammaging) may occur via activation of the nuclear factor erythroid 2 related factor and changes in gut microbiota. A senolytic activity, leading to reduction of cells with the senescent associated secretory phenotype, may be crucial in lifespan prolongation as well as in ancillary properties in age-associated diseases, such as Parkinson's disease. Telomere prolongation may be related to the activity on mitochondrial respiratory factor 1 and on peroxisome gamma proliferator coactivator 1-alpha. Very recent observations on the potential to act on the most severe neurological disorders, such as amyotrophic lateral sclerosis and frontotemporal dementia, have raised considerable hope.

Exploring the heterogeneous targets of metabolic aging at single-cell resolution

Our limited understanding of metabolic aging poses major challenges to comprehending the diverse cellular alterations that contribute to age-related decline, and to devising targeted interventions. This review provides insights into the heterogeneous nature of cellular metabolism during aging and its response to interventions, with a specific focus on cellular heterogeneity and its implications. By synthesizing recent findings using single-cell approaches, we explored the vulnerabilities of distinct cell types and key metabolic pathways. Delving into the cell type-specific alterations underlying the efficacy of systemic interventions, we also discuss the complexity of integrating single-cell data and advocate for leveraging computational tools and artificial intelligence to harness the full potential of these data, develop effective strategies against metabolic aging, and promote healthy aging.

Mechanisms of Senescence and Anti-Senescence Strategies in the Skin

The skin is the layer of tissue that covers the largest part of the body in vertebrates, and its main function is to act as a protective barrier against external environmental factors, such as microorganisms, ultraviolet light and mechanical damage. Due to its important function, investigating the factors that lead to skin aging and age-related diseases, as well as understanding the biology of this process, is of high importance. Indeed, it has been reported that several external and internal stressors contribute to skin aging, similar to the aging of other tissues. Moreover, during aging, senescent cells accumulate in the skin and express senescence-associated factors, which act in a paracrine manner on neighboring healthy cells and tissues. In this review, we will present the factors that lead to skin aging and cellular senescence, as well as ways to study senescence in vitro and in vivo. We will further discuss the adverse effects of the accumulation of chronic senescent cells and therapeutic agents and tools to selectively target and eliminate them.

Metformin Lysosomal Targeting: A Novel Aspect to Be Investigated for Metformin Repurposing in Neurodegenerative Diseases?

Metformin is a widely employed drug in type 2 diabetes. In addition to warranting good short- and long-term glycemic control, metformin displays many intriguing properties as protection against cardiovascular and neurodegenerative diseases, anti-tumorigenic and longevity promotion. In addition to being a low-cost drug, metformin is generally well tolerated. However, despite the enthusiastic drive to aliment these novel studies, many contradictory results suggest the importance of better elucidating the complexity of metformin action in different tissues/cells to establish its possible employment in neurodegenerative diseases. This review summarises recent data identifying lysosomal-dependent processes and lysosomal targets, such as endosomal Na+/H+ exchangers, presenilin enhancer 2 (PEN2), the lysosomal pathway leading to AMP-activated protein kinase (AMPK) activation, and the transcription factor EB (TFEB), modulated by metformin. Lysosomal dysfunctions resulting in autophagic and lysosomal acidification and biogenesis impairment appear to be hallmarks of many inherited and acquired neurodegenerative diseases. Lysosomes are not yet seen as a sort of cellular dump but are crucial in determining key signalling paths and processes involved in the clearance of aggregated proteins. Thus, the possibility of pharmacologically modulating them deserves great interest. Despite the potentiality of metformin in this context, many additional important issues, such as dosing, should be addressed in the future.

Early Life Interventions: Impact on Aging and Longevity

Across mammals, lifespans vary remarkably, spanning over a hundredfold difference. Comparative studies consistently reveal a strong inverse relationship between developmental pace and lifespan, hinting at the potential for early-life interventions (ELIs) to influence aging and lifespan trajectories. Focusing on postnatal interventions in mice, this review explores how ELIs influence development, lifespan, and the underlying mechanisms. Previous ELI studies have employed a diverse array of approaches, including dietary modifications, manipulations of the somatotropic axis, and various chemical treatments. Notably, these interventions have demonstrated significant impacts on aging and lifespan in mice. The underlying mechanisms likely involve pathways related to mitochondrial function, mTOR and AMPK signaling, cellular senescence, and epigenetic alterations. Interestingly, ELI studies may serve as valuable models for investigating the complex regulatory mechanisms of development and aging, particularly regarding the interplay among somatic growth, sexual maturation, and lifespan. In addition, prior research has highlighted the intricacies of experimental design and data interpretation. Factors such as timing, sex-specific effects, administration methods, and animal husbandry practices must be carefully considered to ensure the reliability and reproducibility of results, as well as rigorous interpretation. Addressing these factors is essential for advancing our understanding of how development, aging, and lifespan are regulated, potentially opening avenues for interventions that promote healthy aging.

Metformin enhances endogenous neural stem cells proliferation, neuronal differentiation, and inhibits ferroptosis through activating AMPK pathway after spinal cord injury

BACKGROUND

Inadequate nerve regeneration and an inhibitory local microenvironment are major obstacles to the repair of spinal cord injury (SCI). The activation and differentiation fate regulation of endogenous neural stem cells (NSCs) represent one of the most promising repair approaches. Metformin has been extensively studied for its antioxidative, anti-inflammatory, anti-aging, and autophagy-regulating properties in central nervous system diseases. However, the effects of metformin on endogenous NSCs remains to be elucidated.

METHODS

The proliferation and differentiation abilities of NSCs were evaluated using CCK-8 assay, EdU/Ki67 staining and immunofluorescence staining. Changes in the expression of key proteins related to ferroptosis in NSCs were detected using Western Blot and immunofluorescence staining. The levels of reactive oxygen species, glutathione and tissue iron were measured using corresponding assay kits. Changes in mitochondrial morphology and membrane potential were observed using transmission electron microscopy and JC-1 fluorescence probe. Locomotor function recovery after SCI in rats was assessed through BBB score, LSS score, CatWalk gait analysis, and electrophysiological testing. The expression of the AMPK pathway was examined using Western Blot.

RESULTS

Metformin promoted the proliferation and neuronal differentiation of NSCs both in vitro and in vivo. Furthermore, a ferroptosis model of NSCs using erastin treatment was established in vitro, and metformin treatment could reverse the changes in the expression of key ferroptosis-related proteins, increase glutathione synthesis, reduce reactive oxygen species production and improve mitochondrial membrane potential and morphology. Moreover, metformin administration improved locomotor function recovery and histological outcomes following SCI in rats. Notably, all the above beneficial effects of metformin were completely abolished upon addition of compound C, a specific inhibitor of AMP-activated protein kinase (AMPK).

CONCLUSION

Metformin, driven by canonical AMPK-dependent regulation, promotes proliferation and neuronal differentiation of endogenous NSCs while inhibiting ferroptosis, thereby facilitating recovery of locomotor function following SCI. Our study further elucidates the protective mechanism of metformin in SCI, providing new mechanistic insights for its candidacy as a therapeutic agent for SCI.

Crosstalk between the DNA damage response and cellular senescence drives aging and age-related diseases

Cellular senescence is a crucial process of irreversible cell-cycle arrest, in which cells remain alive, but permanently unable to proliferate in response to distinct types of stressors. Accumulating evidence suggests that DNA damage builds over time and triggers DNA damage response signaling, leading to cellular senescence. Cellular senescence serves as a platform for the perpetuation of inflammatory responses and is central to numerous age-related diseases. Defects in DNA repair genes or senescence can cause premature aging disease. Therapeutic approaches limiting DNA damage or senescence contribute to a rescued phenotype of longevity and neuroprotection, thus suggesting a mechanistic interaction between DNA damage and senescence. Here, we offer a unique perspective on the crosstalk between the DNA damage response pathway and senescence as well as their contribution to age-related diseases. We further summarize recent progress on the mechanisms and therapeutics of senescence, address existing challenges, and offering new insights and future directions in the senescence field.

Zwitterion-Lubricated Hydrogel Microspheres Encapsulated with Metformin Ameliorate Age-Associated Osteoarthritis

Chondrocyte senescence and reduced lubrication play pivotal roles in the pathogenesis of age-related osteoarthritis (OA). In the present study, highly lubricated and drug-loaded hydrogel microspheres are designed and fabricated through the radical polymerization of sulfobetaine (SB)-modified hyaluronic acid methacrylate using microfluidic technology. The copolymer contains a large number of SB and carboxyl groups that can provide a high degree of lubrication through hydration and form electrostatic loading interactions with metformin (Met@SBHA), producing a high drug load for anti-chondrocyte senescence. Mechanical, tribological, and drug release analyses demonstrated enhanced lubricative properties and prolonged drug dissemination of the Met@SBHA microspheres. RNA sequencing (RNA-seq) analysis, network pharmacology, and in vitro assays revealed the extraordinary capacity of Met@SBHA to combat chondrocyte senescence. Additionally, inducible nitric oxide synthase (iNOS) has been identified as a promising protein modulated by Met in senescent chondrocytes, thereby exerting a significant influence on the iNOS/ONOO-/P53 pathway. Notably, the intra-articular administration of Met@SBHA in aged mice ameliorated cartilage senescence and OA pathogenesis. Based on the findings of this study, Met@SBHA emerges as an innovative and promising strategy in tackling age-related OA serving the dual function of enhancing joint lubrication and mitigating cartilage senescence.

Metformin Treatment of Macrophages Increases Microvessel Growth in Three-Dimensional Hydrogel Coculture

The global population is aging rapidly, posing unprecedented challenges to health care systems. This study investigates the often-overlooked role of macrophages in microvascular dysfunction associated with aging. We use a three-dimensional in vitro hydrogel model to assess the effects of both age and metformin, an anti-aging therapeutic, on macrophage interactions with microvasculature. Metformin's broad cellular impact is a subject of significant interest, yet its precise mechanisms remain unclear. Our research reveals that metformin treatment enhances genetic pathways associated with macrophage-mediated support of angiogenesis, resulting in increased microvessel density. Of importance, monocyte chemoattractant protein-1 expression is upregulated with metformin treatment and positively correlated with microvascular volume, shedding light on a potential mechanism for metformin's promotion of macrophage support of vasculogenesis. This work not only uncovers metformin's impact on human macrophages but also supports its potential as an antiaging therapeutic, offering new avenues for combating age-related diseases.

Autophagy and metabolic aging: Current understanding and future applications

"Metabolic aging" refers to the gradual decline in cellular metabolic function across various tissues due to defective hormonal signaling, impaired nutrient sensing, mitochondrial dysfunction, replicative stress, and cellular senescence. While this process usually corresponds with chronological aging, the recent increase in metabolic diseases and cancers occurring at younger ages in humans suggests the premature onset of cellular fatigue and metabolic aging. Autophagy, a cellular housekeeping process facilitated by lysosomes, plays a crucial role in maintaining tissue rejuvenation and health. However, various environmental toxins, hormones, lifestyle changes, and nutrient imbalances can disrupt autophagy in humans. In this review, we explore the connection between autophagy and cellular metabolism, its regulation by extrinsic factors and its modulation to prevent the early onset of metabolic aging.