Metformin as a geroprotector: experimental and clinical evidence

Targeting cellular senescence in kidney diseases and aging: A focus on mesenchymal stem cells and their paracrine factors

Cellular senescence is a phenomenon distinguished by the halting of cellular division, typically triggered by DNA injury or numerous stress-inducing factors. Cellular senescence is implicated in various pathological and physiological processes and is a hallmark of aging. The presence of accumulated senescent cells, whether transiently (acute senescence) or persistently (chronic senescence) plays a dual role in various conditions such as natural kidney aging and different kidney disorders. Elevations in senescent cells and senescence-associated secretory phenotype (SASP) levels correlate with decreased kidney function, kidney ailments, and age-related conditions. Strategies involving senotherapeutic agents like senolytics, senomorphics, and senoinflammation have been devised to specifically target senescent cells. Mesenchymal stem cells (MSCs) and their secreted factors may also offer alternative approaches for anti-senescence interventions. The MSC-derived secretome compromises significant therapeutic benefits in kidney diseases by facilitating tissue repair via anti-inflammatory, anti-fibrosis, anti-apoptotic, and pro-angiogenesis effects, thereby improving kidney function and mitigating disease progression. Moreover, by promoting the clearance of senescent cells or modulating their secretory profiles, MSCs could potentially reverse some age-related declines in kidney function.This review article intends to shed light on the present discoveries concerning the role of cellular senescence in kidney aging and diseases. Furthermore, it outlines the role of senotherapeutics utilized to alleviate kidney damage and aging. It also highlights the possible impact of MSCs secretome on mitigating kidney injury and prolonging lifespan across various models of kidney diseases as a novel senotherapy.

Dietary sucrose determines the regulatory activity of lithium on gene expression and lifespan in Drosophila melanogaster

The amount of dietary sugars and the administration of lithium both impact the lifespan of the fruit fly Drosophila melanogaster. It is noteworthy that lithium is attributed with insulin-like activity as it stimulates protein kinase B/Akt and suppresses the activity of glycogen synthase kinase-3 (GSK-3). However, its interaction with dietary sugar has largely remained unexplored. Therefore, we investigated the effects of lithium supplementation on known lithium-sensitive parameters in fruit flies, such as lifespan, body composition, GSK-3 phosphorylation, and the transcriptome, while varying the dietary sugar concentration. For all these parameters, we observed that the efficacy of lithium was significantly influenced by the sucrose content in the diet. Overall, we found that lithium was most effective in enhancing longevity and altering body composition when added to a low-sucrose diet. Whole-body RNA sequencing revealed a remarkably similar transcriptional response when either increasing dietary sucrose from 1% to 10% or adding 1 mM LiCl to a 1% sucrose diet, characterized by a substantial overlap of nearly 500 differentially expressed genes. Hence, dietary sugar supply is suggested as a key factor in understanding lithium bioactivity, which could hold relevance for its therapeutic applications.

Human trials exploring anti-aging medicines

Here, we summarize the current knowledge on eight promising drugs and natural compounds that have been tested in the clinic: metformin, NAD+ precursors, glucagon-like peptide-1 receptor agonists, TORC1 inhibitors, spermidine, senolytics, probiotics, and anti-inflammatories. Multiple clinical trials have commenced to evaluate the efficacy of such agents against age-associated diseases including diabetes, cardiovascular disease, cancer, and neurodegenerative diseases. There are reasonable expectations that drugs able to decelerate or reverse aging processes will also exert broad disease-preventing or -attenuating effects. Hence, the outcome of past, ongoing, and future disease-specific trials may pave the way to the development of new anti-aging medicines. Drugs approved for specific disease indications may subsequently be repurposed for the treatment of organism-wide aging consequences.

Estimating Type 2 Diabetes Prevalence: A Model of Drug Consumption Data

Observational, cross-sectional prevalence studies are costly and time-consuming. The development of indirect methods estimating prevalence used to obtain faster, less-expensive, and more robust results would be an advantage for several healthcare applications. This study aimed to use the drug dispensing data from community pharmacies to estimate the prevalence of Type 2 Diabetes mellitus (T2DM) in the Portuguese population. A cross-sectional study was conducted using a database of dispensed medicines with an indication for Diabetes mellitus in 2018 and 2021, stratified by geographic region. The methodology was based on a sequential method of acquiring prevalence estimates obtained through exposure to medicines using the daily doses defined per thousand inhabitants per day and adjusted to the rate of adherence to therapy, prescription patterns, and concomitance of antidiabetic drugs. The estimated overall T2DM prevalence in 2018 was 13.9%, and it was 14.2% for 2021. The results show the increased consumption of antidiabetic drugs, with fixed-dose combination antidiabetics and new antidiabetics being particularly important in 2021. This work allowed for the development of a model to obtain the estimated prevalence of T2DM based on drug consumption, using a simple, fast, and robust method that is in line with the available evidence. However, with the recent expanding indications for new antidiabetics, the inclusion of further data in the model needs to be studied.

Frailty in end-stage liver disease: Understanding pathophysiology, tools for assessment, and strategies for management

Frailty and sarcopenia are frequently observed in patients with end-stage liver disease. Frailty is a complex condition that arises from deteriorations across various physiological systems, including the musculoskeletal, cardiovascular, and immune systems, resulting in a reduced ability of the body to withstand stressors. This condition is associated with declined resilience and increased vulnerability to negative outcomes, including disability, hospitalization, and mortality. In cirrhotic patients, frailty is influenced by multiple factors, such as hyperammonemia, hormonal imbalance, malnutrition, ascites, hepatic encephalopathy, and alcohol intake. Assessing frailty is crucial in predicting morbidity and mortality in cirrhotic patients. It can aid in making critical decisions regarding patients' eligibility for critical care and transplantation. This, in turn, can guide the development of an individualized treatment plan for each patient with cirrhosis, with a focus on prioritizing exercise, proper nutrition, and appropriate treatment of hepatic complications as the primary lines of treatment. In this review, we aim to explore the topic of frailty in liver diseases, with a particular emphasis on pathophysiology, clinical assessment, and discuss strategies for preventing frailty through effective treatment of hepatic complications. Furthermore, we explore novel assessment and management strategies that have emerged in recent years, including the use of wearable technology and telemedicine.

Metformin protects fibroblasts from patients with GNE myopathy by restoring autophagic flux via an AMPK/mTOR-independent pathway

UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) myopathy is an autosomal recessive disease characterized by rimmed vacuoles (RVs). Previous studies have shown that metformin protects against several neuromuscular disorders. In the present study, we summarize the clinical features of three GNE patients with the p.D207V mutation. The pathogenesis of GNE myopathy is described, and the significance of metformin in this disease is observed. Skin biopsy-derived fibroblasts from patients with GNE myopathy, carrying a D207V mutation in GNE, were cultured. GNE fibroblasts and control fibroblasts were treated under normal culture conditions, serum starvation conditions, or serum starvation + metformin conditions. Histopathological and immunohistochemical analyses of muscle samples showed that autophagy was involved in the formation of RVs in the muscle of patients. Starved GNE fibroblasts showed decreased autophagy-related proteins and impaired autophagic flow (p < 0.05). The mRFP-GFP-LC3 assay showed that the fusion of autophagosomes with lysosomes was partially blocked in GNE cells. Notably, metformin treatment upregulated the expression of autophagy proteins, increased the number of autolysosomes (p < 0.001), and influenced the viability of GNE cells (p < 0.001). Furthermore, adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and phosphorylated (p)-AMPK expression levels were upregulated in serum-starved GNE fibroblasts, while the mammalian target of rapamycin (mTOR) and p-mTOR expression levels were downregulated in both groups. Metformin treatment inhibited the AMPK-mTOR signaling pathway. Our results suggest that metformin plays a protective role in the GNE fibroblast by restoring autophagic flux and through the AMPK/mTOR-independent pathway.

Extended-release metformin improves cognitive impairment in frail older women with hypertension and diabetes: preliminary results from the LEOPARDESS Study

BACKGROUND

Women have a high risk of frailty independently of age and menopause state. Diabetes and hypertension increase the risk of frailty and cognitive impairment. Metformin has been employed in post-menopausal women and some reports have shown encouraging effects in terms of attenuated frailty. However, the impact on cognitive performance of a recently introduced extended-release formulation of metformin has never been explored.

METHODS

We studied consecutive frail hypertensive and diabetic older women presenting at the ASL (local health authority of the Italian Ministry of Health) Avellino, Italy, from June 2021 to August 2022, who were treated or not with extended-release metformin. We included a control group of frail older males with diabetes and hypertension treated with extended-release metformin and a control group of frail older women with diabetes and hypertension treated with regular metformin.

RESULTS

A total of 145 patients successfully completed the study. At the end of the 6-month follow-up, we observed a significantly different cognitive performance compared to baseline in the group of frail women treated with extended-release metformin (p: 0.007). Then, we compared the follow-up groups and we observed significant differences between frail women treated vs. untreated (p: 0.041), between treated frail women and treated frail men (p: 0.016), and between women treated with extended-release metformin vs. women treated with regular metformin (p: 0.048). We confirmed the crucial role of extended-release metformin applying a multivariable logistic analysis to adjust for potential confounders.

CONCLUSIONS

We evidenced, for the first time to the best of our knowledge, the favorable effects on cognitive impairment of extended-release metformin in frail women with diabetes and hypertension.

Changing ROS, NAD and AMP: A path to longevity via mitochondrial therapeutics

Lifespan of many organisms, from unicellular yeast to extremely complex human organism, strongly depends on the genetic background and environmental factors. Being among most influential target energy metabolism is affected by macronutrients, their caloric values, and peculiarities of catabolism. Mitochondria are central organelles that respond for energy metabolism in eukaryotic cells. Mitochondria generate reactive oxygen species (ROS), which are lifespan modifying metabolites and a kind of biological clock. Oxidized nicotinamide adenine dinucleotide (NAD⁺) and adenosine monophosphate (AMP) are important metabolic intermediates and molecules that trigger or inhibit several signaling pathways involved in gene silencing, nutrient allocation, and cell regeneration and programmed death. A part of NAD⁺ and AMP metabolism is tied to mitochondria. Using substances that able to target mitochondria, as well as allotopic expression of specific enzymes, are envisioned to be innovative approaches to prolong lifespan by modulation of ROS, NAD⁺, and AMP levels. Among substances, an anti-diabetic drug metformin is believed to increase NAD⁺ and AMP levels, indirectly influencing histone deacetylases, involved in gene silencing, and AMP-activated protein kinase, an energy sensor of cells. Mitochondrially targeted derivatives of ubiquinone were found to interact with ROS. A mitochondrially targeted non-proton-pumping NADH dehydrogenase may influence both ROS and NAD⁺ levels. Chapter describes putative how mitochondria-targeted drugs and NADH dehydrogenase extend lifespan, perspectives of creating drugs with similar properties and their usage as senotherapeutic pills are discussed in the chapter.

Metformin Use Is Associated With Lower Mortality in Veterans With Diabetes Hospitalized With Pneumonia

BACKGROUND

Recent studies suggest that metformin use may be associated with improved infectious disease-related outcomes, whereas other papers suggest potentially worse outcomes in serious bacterial infections. Our purpose was to examine the association of prior outpatient prescription of metformin on 30- and 90-day mortality for older veterans with pre-existing diabetes hospitalized with pneumonia.

METHODS

We conducted a retrospective cohort study using national Department of Veterans Affairs data of patients ≥65 years with a prior history of diabetes who were hospitalized with pneumonia over a 10-year period (fiscal years 2002-2012.) For our primary analysis, we created a propensity score and matched metformin users to nonusers 1:1.

RESULTS

We identified 34 759 patients who met the inclusion criteria, 20.3% of whom were prescribed metformin. Unadjusted 30-day mortality was 9.6% for those who received metformin versus 13.9% in nonusers (P < .003), and 90-day mortality was 15.8% for those who received metformin versus 23.0% for nonusers (P < .0001). For the propensity score model, we matched 6899 metformin users to 6899 nonusers. After propensity matching, both 30-day (relative risk [RR]: .86; 95% confidence interval [CI]: .78-.95) and 90-day (RR: .85; 95% CI: .79-.92) mortality was significantly lower for metformin users.

CONCLUSIONS

Prior receipt of metformin was associated with significantly lower mortality after adjusting for potential confounders. Additional research is needed to examine the safety and potential benefits of metformin use in patients with respiratory infections.

The function, mechanisms, and clinical applications of metformin: potential drug, unlimited potentials

Metformin has been used clinically for more than 60 years. As time goes by, more and more miraculous effects of metformin beyond the clinic have been discovered and discussed. In addition to the clinically approved hypoglycemic effect, it also has a positive metabolic regulation effect on the human body that cannot be ignored. Such as anti-cancer, anti-aging, brain repair, cardiovascular protection, gastrointestinal regulation, hair growth and inhibition of thyroid nodules, and other nonclinical effects. Metformin affects almost the entire body in the situation taking it over a long period, and the preventive effects of metformin in addition to treating diabetes are also beginning to be recommended in some guidelines. This review is mainly composed of four parts: the development history of metformin, the progress of clinical efficacy, the nonclinical efficacy of metformin, and the consideration and prospect of its application.

An Examination of Whether Diabetes Control and Treatments Are Associated With Change in Frailty Index Across 8 Years: An Ancillary Exploratory Study From the Action for Health in Diabetes (Look AHEAD) Trial

OBJECTIVE

The aim of this study was to describe cross-sectional and longitudinal associations between glycated hemoglobin (HbA1c) levels and strategies to control type 2 diabetes with baseline levels and 8-year changes in a deficit accumulation frailty index (FI), a commonly used marker of biological aging.

RESEARCH DESIGN AND METHODS

We conducted exploratory analyses from 4,169 participants, aged 45-76 years, who were followed in the Action for Health in Diabetes (Look AHEAD) randomized controlled clinical trial, pooling data across intervention groups. We related baseline and 8-year levels of HbA1c with FI scores using analyses of variance and covariance. Associations between 8-year changes in FI and the use of diabetes medication classes and weight changes were assessed with control for HbA1c levels. Inverse probability weighting was used to assess bias associated with differential follow-up.

RESULTS

Baseline and average HbA1c levels over time of <7%, as compared with ≥8%, were associated with less increase in FI scores over 8 years (both P ≤ 0.002). After adjustment for HbA1c, use of metformin and weight loss >5% were independently associated with slower increases in frailty.

CONCLUSIONS

Lower HbA1c levels among individuals with diabetes are associated with slower biological aging as captured by a deficit accumulation FI. Strategies to control diabetes through weight loss or metformin use may also slow aging.

The Pathogenetic Basis of the Action of Bempedoic Acid

The modern cardiology has a wide range of medications which affect various pathogenetic links of atherosclerosis, but even the best of them still obtain disadvantages causing intolerance and medicine discontinuation. The development of new hypolipidemic medications will allow not only to introduce alternative therapies into the cardiology practice, but also to completely execute the strategy of residual risk reduction by utilizing rational combinations of medications. One of such alternatives could be bempedoic acid, which can have a positive effect on a number of endpoints as the results of third phase trials have shown. These effects are also confirmed in Mendelian randomization studies. The mechanism of action of bempedoic acid is presumably associated with inhibition of the activity of ATP citrate lyase – the enzyme responsible for the breakdown of citrate into acetyl-CoA and oxaloacetate. Acetyl-CoA, in turn, is used by the cell to synthesize cholesterol and fatty acids. Thus, bempedoic acid affects in the same metabolic pathway as statins, but at an earlier stage. According to this, it is possible that medications of these classes will have similar side effects and pleiotropic effects associated with modulation of the mevalonic pathway, such as prenylation regulatory proteins (small GTPases) or reduction of coenzyme Q synthesis. However, there are also some specific features of the pharmacodynamics and pharmacokinetics of bempedoic acid to be considered. In particular, once entered the body, it must be activated via esterification by very long-chain acyl-CoA synthetase-1. The enzyme isoform required for this process is expressed in a tissue-specific manner and, for example, is absent in skeletal myocytes. In addition, citrate, oxaloacetate, and acetyl-CoA are important regulators of many intracellular processes: metabolism, growth and proliferation, mechanotransduction, posttranslational modifications of histones and other proteins. The levels of all three substances are altered by bempedoic acid, although no firm conclusions about the effects of these changes can be drawn at this time. The mentioned features probably have a significant impact on the clinical profile of bempedoic acid and underlie the differences from statins already observed in third phase trials, including, for example, a reduced risk of the onset or worsening of diabetes mellitus while taking bempedoic acid.

Effects of hypoglycaemic therapy on frailty: a multi-dimensional perspective

INTRODUCTION

The prevalence of diabetes is increasing in older people. With increasing age, frailty emerges as a new complication leading to disability. Frailty does not only include physical dysfunction but also involves negative impact on cognition and mood. Triad of impairments (TOI) is a new concept that includes physical frailty, dementia and depression to reflect the wider spectrum of frailty.

AREAS COVERED

Little is known about effects of hypoglycaemic agents on frailty syndrome. A literature search was performed on studies, which reported effects of hypoglycaemic agents on the component of the TOI.

EXPERT OPINION

It appears that most hypoglycaemic agents have some effects on frailty, although the results of clinical studies are inconsistent. Metformin seems to have a consistent and a positive effect on physical frailty. Its effects on cognitive function, however, are inconclusive but tend to be positive. Metformin appeared to improve depressive symptoms. Other agents such as incretins, thiazolidinediones, and sodium glucose transporter-2 inhibitors have some positive effects on cognition and depression. Sulfonylureas, glinides, or insulin have either negative or neutral effects on TOI components. The negative effects of insulin could be partially explained by the negative psychological factors and the frequent episodes of hypoglycemia associated with such therapy.

Senotherapeutics for mesenchymal stem cell senescence and rejuvenation

Mesenchymal stem cells (MSCs) are susceptible to replicative senescence and senescence-associated functional decline, which hampers their use in regenerative medicine. Senotherapeutics are drugs that target cellular senescence through senolytic and senomorphic functions to induce apoptosis and suppress chronic inflammation caused by the senescence-associated secreted phenotype (SASP), respectively. Therefore, senotherapeutics could delay aging-associated degeneration. They could also be used to eliminate senescent MSCs during in vitro expansion or bioprocessing for transplantation. In this review, we discuss the role of senotherapeutics in MSC senescence, rejuvenation, and transplantation, with examples of some tested compounds in vitro. The prospects, challenges, and the way forward in clinical applications of senotherapeutics in cell-based therapeutics are also discussed.

Exploration of Residual Confounding in Analyses of Associations of Metformin Use and Outcomes in Adults With Type 2 Diabetes

IMPORTANCE

Metformin is often used as a first-line therapy for type 2 diabetes; however, frequent discontinuation with reduced kidney function and increased disease severity indicates that a comparison with any other group (eg, nonusers or insulin users) must address significant residual confounding concerns.

OBJECTIVES

To examine the potential for residual confounding in a commonly used observational study design applied to metformin and to propose a more robust study design for future observational studies of metformin.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study with a prevalent user design was conducted using an administrative claims database for Medicare Advantage beneficiaries in the US. Participants were categorized into 2 distinct cohorts: 404 458 individuals with type 2 diabetes and 81 791 individuals with prediabetes. Clinical history was observed in 2018, and end points were observed in 2019. Statistical analyses were conducted between May and December 2021.

EXPOSURES

Prevalent use (recent prescription and history of use on at least 90 of the preceding 365 days) of metformin or insulin but not both at the start of the observation period.

MAIN OUTCOMES AND MEASURES

Total inpatient admission days in 2019 and total medical spending (excluding prescription drugs) in 2019. Each of these measures was treated as a binary outcome (0 vs >0 inpatient days and top 10% vs bottom 90% of medical spending).

RESULTS

The study included 404 458 adults with type 2 diabetes (mean [SD] age, 74.5 [7.5] years; 52.7% female). A strong metformin effect estimate was associated with reduced inpatient admissions (odds ratio, 0.60; 95% CI, 0.58-0.62) and reduced medical expenditures (odds ratio, 0.57; 95% CI, 0.55-0.60). However, implementation of additional robust design features (negative control outcomes and a complementary cohort) revealed that the estimated beneficial effect was attributable to residual confounding associated with individuals' overall health, not metformin itself.

CONCLUSIONS AND RELEVANCE

These findings suggest that common observational study designs for studies of metformin in a type 2 diabetes population are at risk for consequential residual confounding. By performing 2 additional validation checks, the study design proposed here exposes residual confounding that nullifies the initially favorable claim derived from a common study design.

Therapeutic Antiaging Strategies

Aging constitutes progressive physiological changes in an organism. These changes alter the normal biological functions, such as the ability to manage metabolic stress, and eventually lead to cellular senescence. The process itself is characterized by nine hallmarks: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication. These hallmarks are risk factors for pathologies, such as cardiovascular diseases, neurodegenerative diseases, and cancer. Emerging evidence has been focused on examining the genetic pathways and biological processes in organisms surrounding these nine hallmarks. From here, the therapeutic approaches can be addressed in hopes of slowing the progression of aging. In this review, data have been collected on the hallmarks and their relative contributions to aging and supplemented with in vitro and in vivo antiaging research experiments. It is the intention of this article to highlight the most important antiaging strategies that researchers have proposed, including preventive measures, systemic therapeutic agents, and invasive procedures, that will promote healthy aging and increase human life expectancy with decreased side effects.

Life course traumas and cardiovascular disease-the mediating role of accelerated aging

The complex relationship between life course traumas and cardiovascular disease (CVD) and the underpinning pathways are poorly understood. We aimed to (1) examine the associations of three separate assessments including childhood, adulthood (after 16 years of age), and lifetime traumas (childhood or adulthood) with CVD; (2) examine the associations between diverse life course traumatic profiles and CVD; and (3) examine the extent to which PhenoAge, a well-developed phenotypic aging measure, mediated these associations. Using data from 104,939 participants from the UK Biobank, we demonstrate that subgroups of childhood, adulthood, and lifetime traumas were associated with CVD. Furthermore, life course traumatic profiles were significantly associated with CVD. For instance, compared with the subgroup experiencing nonsevere traumas across life course, those who experienced nonsevere childhood and severe adulthood traumas, severe childhood and nonsevere adulthood traumas, or severe traumas across life course had significantly higher odds of CVD (odds ratios: 1.07-1.33). Formal mediation analyses suggested that phenotypic aging partially mediated the above associations. These findings suggest a potential pathway from life course traumas to CVD through phenotypic aging, and underscore the importance of policy programs targeting traumas over the life course in ameliorating inequalities in cardiovascular health.

The interaction between cellular senescence and chronic kidney disease as a therapeutic opportunity

Chronic kidney disease (CKD) is an increasingly serious public health problem in the world, but the effective therapeutic approach is quite limited at present. Cellular senescence is characterized by the irreversible cell cycle arrest, senescence-associated secretory phenotype (SASP) and senescent cell anti-apoptotic pathways (SCAPs). Renal senescence shares many similarities with CKD, including etiology, mechanism, pathological change, phenotype and outcome, however, it is difficult to judge whether renal senescence is a trigger or a consequence of CKD, since there is a complex correlation between them. A variety of cellular signaling mechanisms are involved in their interactive association, which provides new potential targets for the intervention of CKD, and then extends the researches on senotherapy. Our review summarizes the common features of renal senescence and CKD, the interaction between them, the strategies of senotherapy, and the open questions for future research.

Management of Type 2 Diabetes Mellitus in Elderly Patients with Frailty and/or Sarcopenia

The life expectancy of the population is increasing worldwide due to improvements in the prevention, diagnosis, and treatment of diseases. This favors a higher prevalence of type 2 diabetes mellitus (T2DM) in the elderly. Sarcopenia and frailty are also frequently present in aging. These three entities share common mechanisms such as insulin resistance, chronic inflammation, and mitochondrial dysfunction. The coexistence of these situations worsens the prognosis of elderly patients. In this paper, we review the main measures for the prevention and management of sarcopenia and/or frailty in elderly patients with T2DM.

Modulation of Reactive Oxygen Species Homeostasis as a Pleiotropic Effect of Commonly Used Drugs

Age-associated diseases represent a growing burden for global health systems in our aging society. Consequently, we urgently need innovative strategies to counteract these pathological disturbances. Overwhelming generation of reactive oxygen species (ROS) is associated with age-related damage, leading to cellular dysfunction and, ultimately, diseases. However, low-dose ROS act as crucial signaling molecules and inducers of a vaccination-like response to boost antioxidant defense mechanisms, known as mitohormesis. Consequently, modulation of ROS homeostasis by nutrition, exercise, or pharmacological interventions is critical in aging. Numerous nutrients and approved drugs exhibit pleiotropic effects on ROS homeostasis. In the current review, we provide an overview of drugs affecting ROS generation and ROS detoxification and evaluate the potential of these effects to counteract the development and progression of age-related diseases. In case of inflammation-related dysfunctions, cardiovascular- and neurodegenerative diseases, it might be essential to strengthen antioxidant defense mechanisms in advance by low ROS level rises to boost the individual ROS defense mechanisms. In contrast, induction of overwhelming ROS production might be helpful to fight pathogens and kill cancer cells. While we outline the potential of ROS manipulation to counteract age-related dysfunction and diseases, we also raise the question about the proper intervention time and dosage.

The influence of SLC22A3 rs543159 and rs1317652 genetic variants on metformin therapeutic efficacy in newly diagnosed patients with type 2 diabetes mellitus: 25 weeks follow-up study

BACKGROUND AND AIMS

Among anti-diabetic medications, metformin has been proven to be the preferred initial pharmacologic agent for type 2 diabetes mellitus (T2DM) treatment. Despite its safety and efficacy, the response to metformin varies between individuals. Genetic variations, especially within genes involved in pharmacokinetics and pharmacodynamics of metformin (e.g SLC22A3), have been suggested to be responsible for the observed inter-individual differences. By considering the undeniable role of organic cation transporter 3 in hepatic uptake of metformin, this study was aimed to investigate the association of rs543159 and rs1317652 variants in SLC22A3 gene with response to metformin monotherapy in newly diagnosed patients with T2DM.

METHODS

The study included 200 T2DM patients who received metformin monotherapy for 25 weeks. The patients were classified into 2 groups according to their HbA1c values: the responders (reduction in HbA1c levels by at least 1% after 25 weeks treatment with metformin) and non-responders (less than 1% reduction in HbA1c levels after 25 weeks treatment with metformin). We used tetra ARMS-PCR method to determine genotypes of the target variants.

RESULTS

For the rs543159, CA and AA genotypes were more frequent in responders as compared to non-responders (OR = 2.48; 95% CI = 1.28-4.78, P-value = 0.0057) under the dominant model. In case of rs1317652 CC and CT genotypes were more frequent in metformin responders as compared to non-responder group (OR = 2.49; 95% CI = 1.32-4.70, P-value = 0.0043) under the dominant model. Parameters such as fasting blood sugar (FBS), HbA1c, and total cholesterol (TC) levels were significantly lower in the responder group after 25 weeks of metformin monotherapy. Moreover, according to the result of multiple linear regression rs543159 and base line HbA1c values are significantly associated with response to metformin monotherapy.

CONCLUSION

Our results suggested that rs543159 and rs1317652 in SLC22A3 gene might be associated with variability in response to metformin therapy in T2DM patients.

Propensity Score Matching to Determine the Impact of Metformin on All-Cause Mortality in Older Veterans with Diabetes Mellitus

OBJECTIVES

To determine whether metformin is associated with reduced all-cause mortality in older adults with diabetes mellitus as compared with insulin or sulfonylureas, and to evaluate whether the metformin cumulative exposure followed a dose-response relation.

METHODS

Retrospective cohort study with propensity score matching in veterans 65 years old and older with diabetes mellitus. Patients who had new prescriptions for metformin were matched for demographic and clinical factors with patients receiving new prescriptions for insulin or sulfonylureas using propensity score matching. All-cause mortality risks were compared between metformin and insulin/sulfonylureas using multivariate Cox regression models. A similar approach was used for tertiles of cumulative metformin doses.

RESULTS

A sample of 174 veterans taking metformin was matched with 174 who took insulin/sulfonylureas. Most patients were men (97.4%), White (80.45%), and their mean ± standard deviation age was 69.15 ± 7.65 years. Metformin exposure was associated with reduced risk of all-cause mortality (hazard ratio 0.57, 95% confidence interval 0.39-0.84, P = 0.005). The upper tertile of cumulative metformin exposure was associated with lower all-cause mortality in the fully adjusted model (hazard ratio 0.28, 95% confidence interval 0.10-0.77, P = 0.013).

CONCLUSIONS

This propensity matching study shows that metformin exposure is associated with a lower risk of all-cause mortality. Higher metformin cumulative exposure seems to reduce the risk of all-cause mortality in older veterans with diabetes mellitus.

Development and Validation of a New Simple Functional Score in the Older Chinese Population

Background

Existing aging metrics incorporating cognitive and physical function are often not feasible for application in research and clinical practice. Therefore, this study aimed to develop and validate a new simple functional score based on self-reported cognitive and physical function in the older Chinese population.

Methods

The development sample included 3,929 older adults aged 60-95 years from the China Health and Retirement Longitudinal Study (CHARLS). The validation sample included 1,345 older adults aged 60-87 years from the Rugao Longitudinal Aging study (RLAS). Logistic regression models and receiver operating characteristic curves were used to examine the associations of the new functional score with all-cause mortality risk.

Results

Six items were selected to construct the new functional score in CHARLS. This functional score was associated with all-cause mortality risk, with an adjusted odds ratio of 1.10 (95% confidence interval = 1.07, 1.13). This functional score presented additional predictive utility beyond age and sex, as demonstrated by the significantly increased C-statistic, integrated discrimination improvement (IDI), and continuous net reclassification improvement (NRI) (all P < 0.001). Furthermore, this functional score was further validated in RLAS, such that adding the new functional score to a model of age and sex improved all-cause mortality risk discrimination (IDI = 0.036, P < 0.001; NRI = 0.485, P < 0.001). To facilitate the quick screening of the older population with deteriorations in cognitive and physical function, we introduced a publicly available online tool designed for this new functional score.

Conclusions

A new functional score based on six self-reported items was developed and validated in the older Chinese population, and was demonstrated to be a simple and practical tool to assess functional deterioration, showing good feasibility, and performance.

Autophagy and the hallmarks of aging

Autophagy, an essential cellular process that mediates degradation of proteins and organelles in lysosomes, has been tightly linked to cellular quality control for its role as part of the proteostasis network. The current interest in identifying the cellular and molecular determinants of aging, has highlighted the important contribution of malfunctioning of autophagy with age to the loss of proteostasis that characterizes all old organisms. However, the diversity of cellular functions of the different types of autophagy and the often reciprocal interactions of autophagy with other determinants of aging, is placing autophagy at the center of the aging process. In this work, we summarize evidence for the contribution of autophagy to health- and lifespan and provide examples of the bidirectional interplay between autophagic pathways and several of the so-called hallmarks of aging. This central role of autophagy in aging, and the dependence on autophagy of many geroprotective interventions, has motivated a search for direct modulators of autophagy that could be used to slow aging and extend healthspan. Here, we review some of those ongoing therapeutic efforts and comment on the potential of targeting autophagy in aging.

Metformin-enhances resilience via hormesis

The present paper demonstrates that metformin (MF) induced a broad spectrum of hormetic biphasic dose responses in a wide range of experimental studies, affecting multiple organ systems, cell types, and endpoints enhancing resilience to chemical stresses in preconditioning and co-current exposure protocols. Detailed mechanistic evaluations indicate that MF-induced hormetic-adaptive responses are mediated often via the activation of adenosine monophosphate-activated kinase (AMPK) protein and its subsequent upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2). Hormesis-induced protective responses by MF are largely mediated via a vast and highly integrated anti-inflammatory molecular network that enhances longevity and delays the onset and slows the progression of neurodegenerative and other chronic diseases.

Adverse Effects of Metformin From Diabetes to COVID-19, Cancer, Neurodegenerative Diseases, and Aging: Is VDAC1 a Common Target?

Metformin has been used for treating diabetes mellitus since the late 1950s. In addition to its antihyperglycemic activity, it was shown to be a potential drug candidate for treating a range of other diseases that include various cancers, cardiovascular diseases, diabetic kidney disease, neurodegenerative diseases, renal diseases, obesity, inflammation, COVID-19 in diabetic patients, and aging. In this review, we focus on the important aspects of mitochondrial dysfunction in energy metabolism and cell death with their gatekeeper VDAC1 (voltage-dependent anion channel 1) as a possible metformin target, and summarize metformin's effects in several diseases and gut microbiota. We question how the same drug can act on diseases with opposite characteristics, such as increasing apoptotic cell death in cancer, while inhibiting it in neurodegenerative diseases. Interestingly, metformin's adverse effects in many diseases all show VDAC1 involvement, suggesting that it is a common factor in metformin-affecting diseases. The findings that metformin has an opposite effect on various diseases are consistent with the fact that VDAC1 controls cell life and death, supporting the idea that it is a target for metformin.

Rescuing Immunosenescence via Non-Specific Vaccination

Discrepancies in lifespan and healthy-life span are predisposing populations to an increasing burden of age-related disease. Accumulating evidence implicates aging of the immune system, termed immunosenescence, in the pathogenesis of multiple age-related diseases. Moreover, immune dysregulation in the elderly increases vulnerability to infection and dampens pathogen-specific immune responses following vaccination. The health challenges manifesting from these age related deficits have been dramatically exemplified by the current SARS-CoV-2 pandemic. Approaches to either attenuate or reverse functional markers of immunosenescence are therefore urgently needed. Recent evidence suggests systemic immunomodulation via non-specific vaccination with live-attenuated vaccines may be a promising avenue to at least reduce aged population vulnerability to viral infection. This short review describes current understanding of immunosenescence, the historical and mechanistic basis of vaccine-mediated immunomodulation, and the outstanding questions and challenges required for broad adoption.

Autophagy Modulators in Cancer Therapy

Autophagy is a process of self-degradation that plays an important role in removing damaged proteins, organelles or cellular fragments from the cell. Under stressful conditions such as hypoxia, nutrient deficiency or chemotherapy, this process can also become the strategy for cell survival. Autophagy can be nonselective or selective in removing specific organelles, ribosomes, and protein aggregates, although the complete mechanisms that regulate aspects of selective autophagy are not fully understood. This review summarizes the most recent research into understanding the different types and mechanisms of autophagy. The relationship between apoptosis and autophagy on the level of molecular regulation of the expression of selected proteins such as p53, Bcl-2/Beclin 1, p62, Atg proteins, and caspases was discussed. Intensive studies have revealed a whole range of novel compounds with an anticancer activity that inhibit or activate regulatory pathways involved in autophagy. We focused on the presentation of compounds strongly affecting the autophagy process, with particular emphasis on those that are undergoing clinical and preclinical cancer research. Moreover, the target points, adverse effects and therapeutic schemes of autophagy inhibitors and activators are presented.

Prolonged proliferation and delayed senescence of the adipose-derived stem cells grown on the electrospun composite nanofiber co-encapsulated with TiO2 nanoparticles and metformin-loaded mesoporous silica nanoparticles

This study was aimed to investigate the effects of the Poly-ε-Caprolactone/Gelatin nanofibers (PCL/GEL NFs) co-encapsulated with TiO₂ nanoparticles (nTiO₂) and metformin-loaded mesoporous silica nanoparticles (MET@MSNs) on prolonging the in vitro expansion of human adipose-derived stem cells (hADSCs) without inducing cellular senescence and aging. FTIR, BET, FE-SEM, and TEM were applied to characterize the fabricated MET@MSNs and electrospun composite NFs. The presence of inorganic particles, nTiO₂ and MSNs, in the scaffolds improved their mechanical properties and led to a more sustained release of MET with almost the lack of the initial burst release from nTiO₂/MET@MSNs-loaded NFs. The enhanced adhesion, metabolic activity, and proliferation rate of the hADSCs grown on nTiO₂/MET@MSNs-loaded NFs were demonstrated via FE-SEM images, MTT test and PicoGreen assay, respectively, over 28 days of culture. Furthermore, the irregular nanofibrillar structures and the impact of sustained release of MET led to a significant upregulation in the mRNA levels of autophagy (Atg-5, Atg-7, Atg-12, and Beclin-1) and stemness (Nanog3, Sox-2, and Oct-4) markers as well as a considerable down-regulation of p16^INK4A senescence marker. Further, the upregulation of hTERT, enhanced activity of telomerase, and increased telomere length were more pronounced in the hADSCs cultured on nTiO₂/MET@MSNs-loaded NFs as compared to other types of NFs. Overall, our findings demonstrated the potential of the fabricated nanocomposite platform for counteracting cellular senescence and achieving sufficient quantities of fresh hADSCs with preserved stemness for various stem cell-based regenerative medicine purposes.

The plasticity of ageing and the rediscovery of ground-state prevention

In this paper, I present an emerging explanatory framework about ageing and care. In particular, I focus on how, in contrast to most classical accounts of ageing, biomedicine today construes the ageing process as a modifiable trajectory. This framing turns ageing from a stage of inexorable decline into the focus of preventive strategies, harnessing the functional plasticity of the ageing organism. I illustrate this shift by focusing on studies of the demographic dynamics in human population, observations of ageing as an intraspecifically heterogenous phenotype, and the experimental manipulation of longevity, in both model organisms and humans. I suggest that such an explanatory framework about ageing creates the epistemological conditions for the rise of a peculiar form of prevention that does not aim to address a specific condition. Rather it seeks to stall the age-related accumulation of molecular damage and functional deficits, boosting individual resilience against age-related decline. I call this preventive paradigm "ground-state prevention." While new, ground-state prevention bears conceptual resemblance to forms of medical wisdom prominent in classic Galenic medicine, as well as in the Renaissance period.

Biguanides: Species with versatile therapeutic applications

Biguanides are compounds in which two guanidine moieties are fused to form a highly conjugated system. Biguanides are highly basic and hence they are available as salts mostly hydrochloride salts, these cationic species have been found to exhibit many therapeutic properties. This review covers the research and development carried out on biguanides and accounts the various therapeutic applications of drugs containing biguanide group-such as antimalarial, antidiabetic, antiviral, anticancer, antibacterial, antifungal, anti-tubercular, antifilarial, anti-HIV, as well as other biological activities. The aim of this review is to compile all the medicinal chemistry applications of this class of compounds so as to pave way for the accelerated efforts in finding the drug action mechanisms associated with this class of compounds. Importance has been given to the organic chemistry of these biguanide derivatives also.

Repurposing metformin to treat age-related neurodegenerative disorders and ischemic stroke

Aging is a risk factor for major central nervous system (CNS) disorders. More specifically, aging can be inked to neurodegenerative diseases (NDs) because of its deteriorating impact on neurovascular unit (NVU). Metformin, a first line FDA-approved anti-diabetic drug, has gained increasing interest among researchers for its role in improving aging-related neurodegenerative disorders. Additionally, numerous studies have illustrated metformin's role in ischemic stroke, a cerebrovascular disorder in which the NVU becomes dysfunctional which can lead to permanent life-threatening disabilities. Considering metformin's beneficial preclinical actions on various disorders, and the drug's role in alleviating severity of these conditions through involvement in commonly characterized cellular pathways, we discuss the potential of metformin as a suitable drug candidate for repurposing in CNS disorders.

The Current and Potential Therapeutic Use of Metformin-The Good Old Drug

Metformin, one of the oldest oral antidiabetic agents and still recommended by almost all current guidelines as the first-line treatment for type 2 diabetes mellitus (T2DM), has become the medication with steadily increasing potential therapeutic indications. A broad spectrum of experimental and clinical studies showed that metformin has a pleiotropic activity and favorable effect in different pathological conditions, including prediabetes, type 1 diabetes mellitus (T1DM) and gestational diabetes mellitus (GDM). Moreover, there are numerous studies, meta-analyses and population studies indicating that metformin is safe and well tolerated and may be associated with cardioprotective and nephroprotective effect. Recently, it has also been reported in some studies, but not all, that metformin, besides improvement of glucose homeostasis, may possibly reduce the risk of cancer development, inhibit the incidence of neurodegenerative disease and prolong the lifespan. This paper presents some arguments supporting the initiation of metformin in patients with newly diagnosed T2DM, especially those without cardiovascular risk factors or without established cardiovascular disease or advanced kidney insufficiency at the time of new guidelines favoring new drugs with pleotropic effects complimentary to glucose control. Moreover, it focuses on the potential beneficial effects of metformin in patients with T2DM and coexisting chronic diseases.

Metformin prevents brain injury after cardiopulmonary resuscitation by inhibiting the endoplasmic reticulum stress response and activating AMPK-mediated autophagy

BACKGROUND AND AIMS

The neurological damage caused by cardiac arrest (CA) can seriously affect quality of life. We investigated the effect of metformin pretreatment on brain injury and survival in a rat CA/cardiopulmonary resuscitation (CPR) model.

METHODS AND RESULTS

After 14 days of pretreatment with metformin, rats underwent 9 minutes of asphyxia CA/CPR. Survival was evaluated 7 days after restoration of spontaneous circulation; neurological deficit scale (NDS) score was evaluated at days 1, 3, and 7. Proteins related to the endoplasmic reticulum (ER) stress response and autophagy were measured using immunoblotting. Seven-day survival was significantly improved and NDS score was significantly improved in rats pretreated with metformin. Metformin enhanced AMPK-induced autophagy activation. AMPK and autophagy inhibitors removed the metformin neuroprotective effect. Although metformin inhibited the ER stress response, its inhibitory effect was weaker than 4-PBA.

CONCLUSION

In a CA/CPR rat model, 14-day pretreatment with metformin has a neuroprotective effect. This effect is closely related to the activation of AMPK-induced autophagy and inhibition of the ER stress response. Long-term use of metformin can reduce brain damage following CA/CPR.

The effects of metformin on autophagy

Metformin is the first-line option for treating newly diagnosed diabetic patients and also involved in other pharmacological actions, including antitumor effect, anti-aging effect, polycystic ovarian syndrome prevention, cardiovascular action, and neuroprotective effect, etc. However, the mechanisms of metformin actions were not fully illuminated. Recently, increasing researches showed that autophagy is a vital medium of metformin playing pharmacological actions. Nevertheless, results on the effects of metformin on autophagy were inconsistent. Apart from few clinical evidences, more data focused on kinds of no-clinical models. First, many studies showed that metformin could induce autophagy via a number of signaling pathways, including AMPK-related signaling pathways (e.g. AMPK/mTOR, AMPK/CEBPD, MiTF/TFE, AMPK/ULK1, and AMPK/miR-221), Redd1/mTOR, STAT, SIRT, Na⁺/H⁺ exchangers, MAPK/ERK, PK2/PKR/AKT/ GSK3β, and TRIB3. Secondly, some signaling pathways were involved in the process of metformin inhibiting autophagy, such as AMPK-related signaling pathways (AMPK/NF-κB and other undetermined AMPK-related signaling pathways), Hedgehog, miR-570-3p, miR-142-3p, and MiR-3127-5p. Thirdly, two types of signaling pathways including PI3K/AKT/mTOR and endoplasmic reticulum (ER) stress could bidirectionally impact the effectiveness of metformin on autophagy. Finally, multiple signal pathways were reviewed collectively in terms of affecting the effectiveness of metformin on autophagy. The pharmacological effects of metformin combining its actions on autophagy were also discussed. It would help better apply metformin to treat diseases in term of mediating autophagy.

The Mitochondrial Permeability Transition: Nexus of Aging, Disease and Longevity

The activity of the mitochondrial permeability transition pore, mPTP, a highly regulated multi-component mega-channel, is enhanced in aging and in aging-driven degenerative diseases. mPTP activity accelerates aging by releasing large amounts of cell-damaging reactive oxygen species, Ca²⁺ and NAD⁺. The various pathways that control the channel activity, directly or indirectly, can therefore either inhibit or accelerate aging or retard or enhance the progression of aging-driven degenerative diseases and determine lifespan and healthspan. Autophagy, a catabolic process that removes and digests damaged proteins and organelles, protects the cell against aging and disease. However, the protective effect of autophagy depends on mTORC2/SKG1 inhibition of mPTP. Autophagy is inhibited in aging cells. Mitophagy, a specialized form of autophagy, which retards aging by removing mitochondrial fragments with activated mPTP, is also inhibited in aging cells, and this inhibition leads to increased mPTP activation, which is a major contributor to neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. The increased activity of mPTP in aging turns autophagy/mitophagy into a destructive process leading to cell aging and death. Several drugs and lifestyle modifications that enhance healthspan and lifespan enhance autophagy and inhibit the activation of mPTP. Therefore, elucidating the intricate connections between pathways that activate and inhibit mPTP, in the context of aging and degenerative diseases, could enhance the discovery of new drugs and lifestyle modifications that slow aging and degenerative disease.

Aspirin as a Potential Geroprotector: Experimental Data and Clinical Evidence

Aging is a biological process with effects at the molecular, cellular, tissue, organ, system, and organismal levels and is characterized by decline in physical function and higher risks of age-related diseases. The use of anti-aging drugs for disease prevention has become a high priority for science and is a new biomedicine trend. Geroprotectors are compounds which slow aging and increase lifespan of the organism in question. The common painkiller aspirin, a member of the non-steroidal anti-inflammatory drug (NSAID) family, is one of the potential geroprotective agents. Aspirin is often used in treatment of mild to moderate pain. It has anti-inflammatory and anti-pyretic properties and acts as an inhibitor of cyclooxygenase which results in inhibition of prostaglandin. Acetylsalicylic acid as an active compound of aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. Aspirin has shown life-extending effects in numerous model organisms. This chapter reviews the evidence for clinical efficacy of aspirin including cardiovascular disease prevention, anti-cancer effects, and improvement of cognitive function. However, there are some limitations of these therapies, including the risk of excessive bleeding. We have also summarized numerous experimental and analytical data that support health and longevity benefits of aspirin treatment by affecting pro-longevity pathways.

Decline in biological resilience as key manifestation of aging: Potential mechanisms and role in health and longevity

Decline in biological resilience (ability to recover) is a key manifestation of aging that contributes to increase in vulnerability to death with age eventually limiting longevity even in people without major chronic diseases. Understanding the mechanisms of this decline is essential for developing efficient anti-aging and pro-longevity interventions. In this paper we discuss: a) mechanisms of the decline in resilience with age, and aging components that contribute to this decline, including depletion of body reserves, imperfect repair mechanisms, and slowdown of physiological processes and responses with age; b) anti-aging interventions that may improve resilience or attenuate its decline; c) biomarkers of resilience available in human and experimental studies; and d) genetic factors that could influence resilience. There are open questions about optimal anti-aging interventions that would oppose the decline in resilience along with extending longevity limits. However, the area develops quickly, and prospects are exciting.

Repurposing drugs to fight aging: The difficult path from bench to bedside

The steady rise in life expectancy occurred across all developed countries during the last century. This demographic trend is, however, not accompanied by the same healthspan extension. This is since aging is the main risk factor for all age-associated pathological conditions. Therefore, slowing the rate of aging is suggested to be more efficient in preventing or delaying age-related diseases than treat them one by one, which is the common approach in a current pharmacological disease-oriented paradigm. To date, a variety of medications designed to treat particular pathological conditions have been shown to exhibit pro-longevity effects in different experimental models. Among them, there are many commonly used prescription and over-the-counter pharmaceuticals such as metformin, rapamycin, aspirin, statins, melatonin, vitamin antioxidants, etc. All of them are being increasingly investigated in preclinical and clinical trials with the aim of determine whether they have potential for extension of human healthspan. The results from these trials are frequently inconclusive and fall short of initial expectations, suggesting that innovative research ideas and additional translational steps are required to overcome obstacles for implementation of such approaches in clinical practice. In this review, recent advances and challenges in the field of repurposing widely used conventional pharmaceuticals to target the aging process are summarized and discussed.

Effects of inflammatory and anti-inflammatory environments on the macrophage mitochondrial function

Mitochondrial response to inflammation is crucial in the metabolic adaptation to infection. This study aimed to explore the mitochondrial response under inflammatory and anti-inflammatory environments, with a focus on the tricarboxylic acid (TCA) cycle. Expression levels of key TCA cycle enzymes and the autophagy-related protein light chain 3b (LC3b) were determined in raw 264.7 cells treated with lipopolysaccharide (LPS) and metformin (Met). Additionally, reactive oxygen species (ROS) levels and mitochondrial membrane potential were assessed using flow cytometry. Moreover, 8-week-old C57BL/6J mice were intraperitoneally injected with LPS and Met to assess the mitochondrial response in vivo. Upon LPS stimulation, the expression of key TCA enzymes, including citrate synthase, α-ketoglutarate dehydrogenase, and isocitrate dehydrogenase 2, and the mitochondrial membrane potential decreased, whereas the levels of LC3b and ROS increased. However, treatment with Met inhibited the reduction of LPS-induced enzyme levels as well as the elevation of LC3b and ROS levels. In conclusion, the mitochondrial TCA cycle is affected by the inflammatory environment, and the LPS-induced effects can be reversed by Met treatment.

Nutrients and Pathways that Regulate Health Span and Life Span

Both life span and health span are influenced by genetic, environmental and lifestyle factors. With the genetic influence on human life span estimated to be about 20–25%, epigenetic changes play an important role in modulating individual health status and aging. Thus, a main part of life expectance and healthy aging is determined by dietary habits and nutritional factors. Excessive or restricted food consumption have direct effects on health status. Moreover, some dietary interventions including a reduced intake of dietary calories without malnutrition, or a restriction of specific dietary component may promote health benefits and decrease the incidence of aging-related comorbidities, thus representing intriguing potential approaches to improve healthy aging. However, the relationship between nutrition, health and aging is still not fully understood as well as the mechanisms by which nutrients and nutritional status may affect health span and longevity in model organisms. The broad effect of different nutritional conditions on health span and longevity occurs through multiple mechanisms that involve evolutionary conserved nutrient-sensing pathways in tissues and organs. These pathways interacting each other include the evolutionary conserved key regulators mammalian target of rapamycin, AMP-activated protein kinase, insulin/insulin-like growth factor 1 pathway and sirtuins. In this review we provide a summary of the main molecular mechanisms by which different nutritional conditions, i.e., specific nutrient abundance or restriction, may affect health span and life span.

The role of autophagy in abdominal aortic aneurysm: protective but dysfunctional

Autophagy, an evolutionarily conserved mechanism that promotes cell survival by recycling nutrients and degrading long-lived proteins and dysfunctional organelles, is an important defense mechanism, and its attenuation has been well documented in senescence and aging-related diseases. Abdominal aortic aneurysm (AAA), a well-known aging-related disease, has been defined as a chronic degenerative process in the abdominal aortic wall; however, the complete mechanism is unknown, and a clinical treatment is lacking. Accumulating evidence has recently revealed that numerous drugs that can induce autophagy are effective in the treatment of AAA. The purpose of this systematic review was to focus on the cross-talk between autophagy and high-risk factors and the potential pathogenesis of AAA to understand not only the host defense and pathogenesis but also potential treatments.

Gerobiotics: probiotics targeting fundamental aging processes

Aging is recognized as a common risk factor for many chronic diseases and functional decline. The newly emerging field of geroscience is an interdisciplinary field that aims to understand the molecular and cellular mechanisms of aging. Several fundamental biological processes have been proposed as hallmarks of aging. The proposition of the geroscience hypothesis is that targeting holistically these highly integrated hallmarks could be an effective approach to preventing the pathogenesis of age-related diseases jointly, thereby improving the health span of most individuals. There is a growing awareness concerning the benefits of the prophylactic use of probiotics in maintaining health and improving quality of life in the elderly population. In view of the rapid progress in geroscience research, a new emphasis on geroscience-based probiotics is in high demand, and such probiotics require extensive preclinical and clinical research to support their functional efficacy. Here we propose a new term, "gerobiotics", to define those probiotic strains and their derived postbiotics and para-probiotics that are able to beneficially attenuate the fundamental mechanisms of aging, reduce physiological aging processes, and thereby expand the health span of the host. We provide a thorough discussion of why the coining of a new term is warranted instead of just referring to these probiotics as anti-aging probiotics or with other similar terms. In this review, we highlight the needs and importance of the new field of gerobiotics, past and currently on-going research and development in the field, biomarkers for potential targets, and recommended steps for the development of gerobiotic products. Use of gerobiotics could be a promising intervention strategy to improve health span and longevity of humans in the future.

Targeting Aging Pathways in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) has become a global epidemic and is the third leading cause of death worldwide. COPD is characterized by chronic airway inflammation, loss of alveolar-capillary units, and progressive decline in lung function. Major risk factors for COPD are cigarette smoking and aging. COPD-associated pathomechanisms include multiple aging pathways such as telomere attrition, epigenetic alterations, altered nutrient sensing, mitochondrial dysfunction, cell senescence, stem cell exhaustion and chronic inflammation. In this review, we will highlight the current literature that focuses on the role of age and aging-associated signaling pathways as well as their impact on current treatment strategies in the pathogenesis of COPD. Furthermore, we will discuss established and experimental COPD treatments including senolytic and anti-aging therapies and their potential use as novel treatment strategies in COPD.

Benefits of Metformin in Attenuating the Hallmarks of Aging

Biological aging involves an interplay of conserved and targetable molecular mechanisms, summarized as the hallmarks of aging. Metformin, a biguanide that combats age-related disorders and improves health span, is the first drug to be tested for its age-targeting effects in the large clinical trial-TAME (targeting aging by metformin). This review focuses on metformin's mechanisms in attenuating hallmarks of aging and their interconnectivity, by improving nutrient sensing, enhancing autophagy and intercellular communication, protecting against macromolecular damage, delaying stem cell aging, modulating mitochondrial function, regulating transcription, and lowering telomere attrition and senescence. These characteristics make metformin an attractive gerotherapeutic to translate to human trials.

Mutations in genes cnc or dKeap1 modulate stress resistance and metabolic processes in Drosophila melanogaster

The transcription factor Nrf2 and its negative regulator Keap1 play important roles in the maintenance of redox homeostasis in animal cells. Nrf2 activates defenses against oxidative stress and xenobiotics. Homologs of Nrf2 and Keap1 are present in Drosophila melanogaster (CncC and dKeap1, respectively). The aim of this study was to explore effects of CncC deficiency (due to mutation in the cnc gene) or enhanced activity (due to mutation in the dKeap1 gene) on redox status and energy metabolism of young adult flies in relation to behavioral traits and resistance to a number of stressors. Deficiency in either CncC or dKeap1 delayed pupation and increased climbing activity and heat stress resistance in 2-day-old adult flies. Males and females of the ∆keap1 line shared some similarities such as elevated antioxidant defense as well as lower triacylglyceride and higher glucose levels. Males of the ∆keap1 line also had a higher activity of hexokinase, whereas ∆keap1 females showed higher glycogen levels and lower values of respiratory control and ATP production than flies of the control line. Mutation of cnc gene in allele cnc^EY08884 caused by insertion of P{EPgy2} transposon in cnc promotor did not affect significantly the levels of metabolites and redox parameters, and even activated some components of antioxidant defense. These data suggest that the mutation can be hypomorphic as well as CncC protein can be dispensable for adult fruit flies under physiological conditions. In females, CncC mutation led to lower mitochondrial respiration, higher hexokinase activity and higher fecundity as compared with the control line. Either CncC activation or its deficiency affected stress resistance of flies.

Is There an Association Between Metformin Exposure and Frailty?

Frailty is a state of vulnerability to stressors resulting in higher morbidity, mortality, and utilization in older adults. Frailty and type 2 diabetes mellitus share similar pathophysiological mechanisms which metformin may target. The purpose of this study was to determine whether exposure to metformin is associated with frailty in veterans. This is a cross-sectional study of veterans 65 years and older with type 2 diabetes who were screened for frailty between January 2016 and August 2017. We constructed a 44-item Frailty Index including multiple variables using a deficit accumulation framework. After adjustment for covariates, the association was calculated using binomial logistic regression models with frailty status as the outcome variable, and metformin exposure as the independent variable. Patients were 98.3% male and 56.7% White with a mean age of 72.9 (SD = 6.8) years. The proportion of robust, prefrail and frail patients was 2.9% (n = 22), 46.7 % (n = 356) and 50.5% (n = 385), respectively. In binomial logistic regression, exposure to metformin was associated with lower risk for frailty, adjusted odds ratio (OR) = .55 (95% confidence interval [CI] = .39–.77), p ≤ .001. This study shows that exposure to metformin was associated with lower risk for frailty in community-dwelling veterans.