The free radical theory of aging matures

Oral subchronic toxicity study and genetic toxicity evaluation of mitoquinone mesylate

Mitochondrial dysfunction and excessive reactive oxygen species production contributes to the pathophysiology of aging. Coenzyme Q10 is thought to protect mitochondria from oxidative damage; thus, mitoquinone was developed as mitochondria-targeted analogue with similar antioxidant activity. Mitoquinone is the oxidized form of mitoquinol. Mitoquinone/mitoquinol mesylate has been proposed as a food ingredient. As part of the safety analysis, we performed genotoxicity assays and a 39-week toxicity study to determine overall toxicity potential. Mitoquinone mesylate showed no evidence of genotoxic potential in two in vitro assays, bacterial reverse mutation and human lymphocyte chromosome aberration, nor in the in vivo micronucleus test in rats. In the 39-week study in dogs, there were no findings observed, which were considered to represent adverse systemic toxicity; therefore, the high dose level (40 mg/kg/day) was considered the NOAEL. The principal findings in this study were fecal disturbances and vomiting. These findings were considered to be due to a local, possibly irritant effect of the test substance on the gastrointestinal tract and were not considered adverse as there were no impacts on clinical or histopathology. This highest dose exceeds the expected daily human intake more than 100-fold. Data from well-designed clinical trials actively collecting safety endpoints corroborate that 20 mg/day can be safely consumed and is not likely to result in significant gastrointestinal complaints. These results support the conclusion that the use of mitoquinone/mitoquinol mesylate as a food ingredient is safe.

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.

The structure elucidation, anti-aging and hypoglycemic effects of an O-acetyl mannoglucan from the bulbs of Lanzhou lily

An O-acetyl mannoglucan (BHP-1) from Lanzhou lily bulbs was structurally elucidated using partial acid hydrolysis, GC-MS, and 2D NMR techniques (COSY, NOESY, HSQC and HMBC) built on prior research, revealing a backbone of -α-D-(1 → 4)-Glcp-β-D-(1 → 4)-Manp- with the most potential side chains -α-D-(1 → 4)-Glcp-β-D-(1 → 4)-Manp-α-D-(1 → 4)-Glcp-α-D-(1 → Glcp- and -α-D-(1 → 4)-Glcp-β-D-(1 → 4)-Manp-α-D-(1 → Glcp-, attached to O-2 and O-3 of glucose and mannose residues, and featuring O-acetyl groups at O-2 or O-3 position of mannose. The terminal residue was α-D-(1 → Glcp. BHP-1 demonstrated anti-aging and hypoglycemic effects, as assessed by C. elegans model and glycolytic enzyme effect in vitro, respectively. The results showed that BHP-1 dose-dependently prolonged lifespan of C. elegans by 33 % at 4 mg/mL under normal conditions, with greater extensions under thermal and oxidative stress (50 % and 80 % increases, respectively, p < 0.05), which were attributed to enhanced antioxidant enzymes (SOD and CAT) and lowered MDA levels of C. elegans. Additionally, BHP-1 exhibited remarkable inhibition on α-glucosidase (93 %) and moderate inhibition on α-amylase (53 %) at 4 mg/mL, with competitive inhibition of α-glucosidase and mixed non-competitive inhibition of α-amylase, respectively. These potential effects might be linked to BHP-1's diverse sugar linkages, higher content of Glc, and certain O-acetyl contents.

Superoxide signal orchestrates tetrathiomolybdate-induced longevity via ARGK-1 in Caenorhabditis elegans

PURPOSE

While reactive oxygen species (ROS) have been identified as key redox signaling agents contributing to aging process, which and how specific oxidants trigger healthy longevity remain unclear. This paper aimed to explore the precise role and signaling mechanism of superoxide (O2•-) in health and longevity.

METHODS

A tool for precise regulation of O2•- levels in vivo was developed based on the inhibition of superoxide dismutase 1 (SOD1) by tetrathiomolybdate (TM) in Caenorhabditis elegans (C. elegans). Then, we examined the effects of TM on lifespan, reproduction, lipofuscin accumulation, mobility, and stress resistance. Finally, the signaling mechanism for longevity induced by TM-O2•- was screened by transcriptome analysis and tested in sod-1 and argk-1 RNAi strains, sod-2, sod-3, and daf-16 mutants.

RESULTS

TM promoted longevity in C. elegans with a concomitant extension of healthy lifespan as indicated by increasing fertility and mobility and reducing lipofuscin accumulation, as well as enhanced resistance to different abiotic stresses. Mechanically, TM could precisely regulate O2•- levels in nematodes via modulating SOD1 activity. An O2•- scavenger Mn(III)TBAP abolished TM-induced lifespan extension, while an O2•- generator paraquat at low concentration mimicked the life prolongation effects. The longevity in TM-treated worms was abolished by sod-1 RNAi but was not affected in sod-2 or sod-3 mutants. Further transcriptome analysis revealed arginine kinase ARGK-1 and its downstream insulin/insulin-like growth factor 1 signaling (IIS) as potential effectors for TM-O2•‾-induced longevity, and argk-1 RNAi or daf-16 mutant nullified the longevity.

CONCLUSIONS

These findings indicate that it is feasible to precisely control specific oxidant in vivo and O2•- orchestrates TM-induced health and longevity in C. elegans via ARGK-1-IIS axis.

Apoptosis and Oxidative Stress in Human Intestinal Epithelial Caco-2 Cells Caused by Marine Phycotoxin Azaspiracid-2

When humans consume seafood contaminated by lipophilic polyether phycotoxins, such as azaspiracids (AZAs), the toxins are mainly leached and absorbed in the small intestine, potentially causing intestinal damage. In this study, human intestinal epithelial Caco-2 cells were used to investigate the adverse effects of azaspiracid-2 (AZA-2) on human intestinal epithelial cells. Cell viability, apoptosis, oxidative damage and mitochondrial ultrastructure were investigated, and ribonucleic acid sequence (RNA-seq) analysis was applied to explore the potential mechanisms of AZA-2 toxicity to Caco-2 cells. Results showed that AZA-2 significantly reduced the proliferation of Caco-2 cells in a concentration-dependent response, and the 48 h EC50 of AZA-2 was 12.65 nmol L-1. AZA-2 can induce apoptosis in Caco-2 cells in a dose-dependent manner. Visible mitochondrial swelling, cristae disintegration, membrane rupture and autophagy were observed in Caco-2 cells exposed to AZA-2. Reactive oxygen species (ROS) and malondialdehyde (MDA) content were significantly increased in Caco-2 cells after 48 h of exposure to 1 and 10 nmol L-1 of AZA-2. Transcriptome analysis showed that KEGG pathways related to cellular oxidative damage and lipid metabolism were affected, mainly including mitophagy, oxidative phosphorylation, cholesterol metabolism, vitamin digestion and absorption, bile secretion and the peroxisome proliferator-activated receptor signaling pathway. The cytotoxic effects of AZA-2 on Caco-2 cells may be associated with ROS-mediated autophagy and apoptosis in mitochondrial cells. Results of this study improve understanding of the cytotoxicity and molecular mechanisms of AZA-2 on Caco-2 cells, which is significant for protecting human health.

The Fungicide Ipconazole Can Activate Mediators of Cellular Damage in Rat Brain Regions

This study aimed to investigate the toxicity of the fungicide ipconazole on oxidative status, cell death and inflammasome complex activation in the hypothalamus, cerebral cortex, striatum and hippocampus of rats. Female albino rats were randomly divided into a control group and four groups treated with ipconazole at doses of 1, 5, 10 and 20 mg/kg b.w., administered for six days. Ipconazole significantly increased MDA and ROS levels in all brain regions studied, while reducing catalase enzyme activity. The molecular expression of cell death-related genes (AKT1, APAF1, BNIP3, CASP3 and BAX) and the inflammasome complex (CASP1, IL1β, IL6, NLRP3, NFĸB and TNFα) was also assessed, showing increased expression in at least one brain region. The findings demonstrate that ipconazole induces central nervous system toxicity in mammals, highlighting its potential role as a risk factor in the development of neurodegenerative disorders in individuals exposed to this contaminant.

Full-length direct RNA sequencing uncovers stress-granule dependent RNA decay upon cellular stress

Cells react to stress by triggering response pathways, leading to extensive alterations in the transcriptome to restore cellular homeostasis. The role of RNA metabolism in shaping the cellular response to stress is vital, yet the global changes in RNA stability under these conditions remain unclear. In this work, we employ direct RNA sequencing with nanopores, enhanced by 5' end adaptor ligation, to comprehensively interrogate the human transcriptome at single-molecule and nucleotide resolution. By developing a statistical framework to identify robust RNA length variations in nanopore data, we find that cellular stress induces prevalent 5' end RNA decay that is coupled to translation and ribosome occupancy. Unlike typical RNA decay models in normal conditions, we show that stress-induced RNA decay is dependent on XRN1 but does not depend on deadenylation or decapping. We observed that RNAs undergoing decay are predominantly enriched in the stress granule transcriptome while inhibition of stress granule formation via genetic ablation of G3BP1 and G3BP2 rescues RNA length. Our findings reveal RNA decay as a key determinant of RNA metabolism upon cellular stress and dependent on stress-granule formation.

NOX4-reactive oxygen species axis: critical regulators of bone health and metabolism

Bone marrow stromal cells (BMSCs) play a significant role in bone metabolism as they can differentiate into osteoblasts, bone marrow adipocytes (BMAds), and chondrocytes. BMSCs chronically exposed to nutrient overload undergo adipogenic programming, resulting in bone marrow adipose tissue (BMAT) formation. BMAT is a fat depot transcriptionally, metabolically, and morphologically distinct from peripheral adipose depots. Reactive oxygen species (ROS) are elevated in obesity and serve as important signals directing BMSC fate. ROS produced by the NADPH oxidase (NOX) family of enzymes, such as NOX4, may be responsible for driving BMSC adipogenesis at the expense of osteogenic differentiation. The dual nature of ROS as both cellular signaling mediators and contributors to oxidative stress complicates their effects on bone metabolism. This review discusses the complex interplay between ROS and BMSC differentiation in the context of metabolic bone diseases.Special attention is paid to the role of NOX4-ROS in regulating cellular processes within the bone marrow microenvironment and potential target in metabolic bone diseases.

Down-regulating the stress axis: Living in the present while preparing for the future

The measurement of glucocorticoid (GC) hormones provides us with a window into the stress physiology of vertebrates and the adaptative responses they use to cope with predictable and unpredictable changes in the environment. Baseline GCs inform us about the metabolic demands they are subject to at that point in their yearly life-history stage, whereas GC changes (often increases) in response to acute challenges inform us on their capacity to cope with more immediate environmental challenges. However, baseline GC levels and the kinetics of GC responses to acute stressors can vary substantially among and within species, depending on individual characteristics (age, sex, condition, life-history stage). In addition, a thorough understanding of the stress status of an animal requires moving beyond the measurement of GCs alone by focusing on downstream measures of metabolic activation, such as oxidative stress. Here, we evaluated the changes in blood cortisol and oxidative stress markers in wild adult Columbian ground squirrels (Urocitellus columbianus), following a 30-min capture-handling stress performed in mid-late June. Measurements were taken when males were post-reproductive and preparing for hibernation and adult females were weaning litters. We found three key results. First, the time-course of GC increase was markedly slower (by an order of magnitude) than what is currently reported in the literature for most species of mammals, birds and reptiles. Second, there were marked differences in the male and female response, linked to differences in life-history stage: females close to weaning had abolished GC responses, whereas post-reproductive males did not. Third, there were mild to moderate increases in oxidative damage and decreases in oxidative defenses in response to our short-term challenge, consistent with the idea that short-term acute metabolic activation may carry physiological costs. However, these changes were not correlated to the changes in GCs, a novel result suggesting a disconnect between the hormonal stress response and oxidative damage.

Multigenerational exposure to temperature influences mitochondrial oxygen fluxes in the Medaka fish (Oryzias latipes)

AIM

Thermal sensitivity of cellular metabolism is crucial for animal physiology and survival under climate change. Despite recent efforts, effects of multigenerational exposure to temperature on the metabolic functioning remain poorly understood. We aimed at determining whether multigenerational exposure to temperature modulate the mitochondrial respiratory response of Medaka fish.

METHODS

We conducted a multigenerational exposure with Medaka fish reared multiple generations at 20 and 30°C (COLD and WARM fish, respectively). We then measured the oxygen consumption of tail muscle at two assay temperatures (20 and 30°C). Mitochondrial function was determined as the respiration supporting ATP synthesis (OXPHOS) and the respiration required to offset proton leak (LEAK(Omy)) in a full factorial design (COLD-20°C; COLD-30°C; WARM-20°C; WARM-30°C).

RESULTS

We found that higher OXPHOS and LEAK fluxes at 30°C compared to 20°C assay temperature. At each assay temperature, WARM fish had lower tissue oxygen fluxes than COLD fish. Interestingly, we did not find significant differences in respiratory flux when mitochondria were assessed at the rearing temperature of the fish (i.e., COLD-20°C vs. WARM -30°C).

CONCLUSION

The lower OXPHOS and LEAK capacities in warm fish are likely the result of the multigenerational exposure to warm temperature. This is consistent with a modulatory response of mitochondrial capacity to compensate for potential detrimental effects of warming on metabolism. Finally, the absence of significant differences in respiratory fluxes between COLD-20°C and WARM-30°C fish likely reflects an optimal respiration flux when organisms adapt to their thermal conditions.

The Double-Edged Sword of Total Antioxidant Capacity: Clinical Significance and Personal Experience

Oxidative stress (OS) could be a condition underlying several human diseases, despite the physiological role of reactive oxygen species (oxidative eustress). Therefore, antioxidant compounds could represent a modulatory mechanism for maintaining a proper redox balance and redox signaling. When antioxidants are insufficient or overwhelmed, OS ensues, causing multiple damages at molecular, tissue, and cellular levels. This study focuses on the role of total antioxidant capacity (TAC) as a biomarker to be interpreted according to several clinical scenarios. After a brief description of various assay methods to elucidate terminology and physiopathological roles, we focus on the hormonal influence on TAC in blood plasma and other biological fluids, as different endocrine systems can modulate the antioxidant response. Furthermore, OS characterizes several endocrinopathies through different mechanisms: an inadequate antioxidant response to an increase in reducing equivalents (reductive distress) or a marked consumption of antioxidants (oxidative distress), which leads to low TAC values. An increased TAC could instead represent an adaptive mechanism, suggesting a situation of OS. Hence, the clinical context is fundamental for a correct interpretation of TAC. This review aims to provide the reader with a general overview of oxidative stress in several clinical examples of endocrine relevance, such as metabolic syndrome, non-thyroid illness syndrome, hypopituitarism, and infertility. Finally, the impact of dietary and surgical interventions on TAC in the model of metabolic syndrome is highlighted, along with personal experience.

Characterization of AICAR transformylase/IMP cyclohydrolase (ATIC) bifunctional enzyme from Candidatus Liberibacer asiaticus

The bifunctional enzyme, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase/inosine monophosphate (IMP) cyclohydrolase (ATIC) is involved in catalyzing penultimate and final steps of purine de novo biosynthetic pathway crucial for the survival of organisms. The present study reports the characterization of ATIC from Candidatus Liberibacer asiaticus (CLasATIC) along with the identification of potential inhibitor molecules and evaluation of cell proliferative activity. CLasATIC showed both the AICAR Transformylase (AICAR TFase) activity for substrates, 10-f-THF (Km, 146.6 μM and Vmax, 0.95 μmol/min/mg) and AICAR (Km, 34.81 μM and Vmax, 0.56 μmol/min/mg) and IMP cyclohydrolase (IMPCHase) activitiy (Km, 1.81 μM and Vmax, 2.87 μmol/min/mg). The optimum pH and temperature were also identified for the enzyme activity. In-silico study has been conducted to identify potential inhibitor molecules through virtual screening and MD simulations. Out of many compounds, HNBSA, diosbulbin A and lepidine D emerged as lead compounds, exhibiting higher binding energy and stability for CLasATIC than AICAR. ITC study reports higher binding affinities for HNBSA and diosbulbin A (Kd, 12.3 μM and 34.2 μM, respectively) compared to AICAR (Kd, 83.4 μM). Likewise, DSC studies showed enhanced thermal stability for CLasATIC in the presence of inhibitors. CD and Fluorescence studies revealed significant conformational changes in CLasATIC upon binding of the inhibitors. CLasATIC demonstrated potent cell proliferative, wound healing and ROS scavenging properties evaluated by cell-based bioassays using CHO cells. This study highlights CLasATIC as a promising drug target with potential inhibitors for managing CLas and its unique cell protective, wound-healing properties for future biotechnological applications.

PGC1-Alpha/Sirt3 Signaling Pathway Mediates the Anti-Pulmonary Fibrosis Effect of Hirudin by Inhibiting Fibroblast Senescence

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrotic lung disease for which there is a lack of effective pharmacological treatments. Hirudin, a natural peptide extracted from leeches, has been used for broad pharmacological purposes. In this study, we investigated the therapeutic effects of hirudin on IPF and its related mechanism of action. By constructing a mouse model of pulmonary fibrosis and treating it with hirudin in vivo, we found that hirudin exerted anti-fibrotic, anti-oxidative, and anti-fibroblast senescence effects. Moreover, using an in vitro model of stress-induced premature senescence in primary mouse lung fibroblasts and treating with hirudin, we observed inhibition of fibroblast senescence and upregulation of PGC1-alpha and Sirt3 expression. However, specific silencing of PGC1-alpha or Sirt3 suppressed the anti-fibroblast senescence effect of hirudin. Thus, the PGC1-alpha/Sirt3 pathway mediates the anti-fibroblast senescence effect of hirudin, potentially serving as a molecular mechanism underlying its anti-fibrosis and anti-oxidative stress effects exerted on the lungs.

The Involvement of Antioxidants in Cognitive Decline and Neurodegeneration: Mens Sana in Corpore Sano

With neurodegenerative disorders being on the rise, a great deal of research from multiple fields is being conducted in order to further knowledge and propose novel therapeutic interventions. Among these investigations, research on the role of antioxidants in contrasting cognitive decline is putting forward interesting and promising results. In this review, we aim to collect evidence that focused on the role of a variety of antioxidants and antioxidant-rich foods in improving or stabilizing cognitive functions, memory, and Alzheimer's disease, the most common neurodegenerative disorder. Specifically, we considered evidence collected on humans, either through longitudinal studies or randomized, placebo-controlled ones, which evaluated cognitive performance, memory abilities, or the progression level of neurodegeneration. Overall, despite a great deal of variety between study protocols, cohorts of participants involved, neuropsychological tests used, and investigated antioxidants, there is a solid trend that suggests that the properties of antioxidants may be helpful in hampering cognitive decline in older people. Thus, the help of future research that will further elucidate the role of antioxidants in neuroprotection will lead to the development of novel interventions that will take into account such findings to provide a more global approach to treating neurodegenerative disorders.

Mitophagy in relation to chronic inflammation/ROS in aging

Various assaults on mitochondria occur during the human aging process, contributing to mitochondrial dysfunction. This mitochondrial dysfunction is intricately connected with aging and diseases associated with it. In vivo, the accumulation of defective mitochondria can precipitate inflammatory and oxidative stress, thereby accelerating aging. Mitophagy, an essential selective autophagy process, plays a crucial role in managing mitochondrial quality control and homeostasis. It is a highly specialized mechanism that systematically removes damaged or impaired mitochondria from cells, ensuring their optimal functioning and survival. By engaging in mitophagy, cells are able to maintain a balanced and stable environment, free from the potentially harmful effects of dysfunctional mitochondria. An ever-growing body of research highlights the significance of mitophagy in both aging and age-related diseases. Nonetheless, the association between mitophagy and inflammation or oxidative stress induced by mitochondrial dysfunction remains ambiguous. We review the fundamental mechanisms of mitophagy in this paper, delve into its relationship with age-related stress, and propose suggestions for future research directions.

Immortalised murine R349P desmin knock-in myotubes exhibit a reduced proton leak and decreased ADP/ATP translocase levels in purified mitochondria

Desmin gene mutations cause myopathies and cardiomyopathies. Our previously characterised R349P desminopathy mice, which carry the ortholog of the common human desmin mutation R350P, showed marked alterations in mitochondrial morphology and function in muscle tissue. By isolating skeletal muscle myoblasts from offspring of R349P desminopathy and p53 knock-out mice, we established an immortalised cellular disease model. Heterozygous and homozygous R349P desmin knock-in and wild-type myoblasts could be well differentiated into multinucleated spontaneously contracting myotubes. The desminopathy myoblasts showed the characteristic disruption of the desmin cytoskeleton and desmin protein aggregation, and the desminopathy myotubes showed the characteristic myofibrillar irregularities. Long-term electrical pulse stimulation promoted myotube differentiation and markedly increased their spontaneous contraction rate. In both heterozygous and homozygous R349P desminopathy myotubes, this treatment restored a regular myofibrillar cross-striation pattern as seen in wild-type myotubes. High-resolution respirometry of mitochondria purified from myotubes by density gradient ultracentrifugation revealed normal oxidative phosphorylation capacity, but a significantly reduced proton leak in mitochondria from the homozygous R349P desmin knock-in cells. Consistent with a reduced proton flux across the inner mitochondrial membrane, our quantitative proteomic analysis of the purified mitochondria revealed significantly reduced levels of ADP/ATP translocases in the homozygous R349P desmin knock-in genotype. As this alteration was also detected in the soleus muscle of R349P desminopathy mice, which, in contrast to the mitochondria purified from cultured cells, showed a variety of other dysregulated mitochondrial proteins, we consider this finding to be an early step in the pathogenesis of secondary mitochondriopathy in desminopathy.

Senegenin Attenuates Pulmonary Fibrosis by Inhibiting Oxidative-Stress-Induced Epithelial Cell Senescence through Activation of the Sirt1/Pgc-1α Signaling Pathway

Idiopathic pulmonary fibrosis is a fatal interstitial lung disease for which effective drug therapies are lacking. Senegenin, an effective active compound from the traditional Chinese herb Polygala tenuifolia Willd, has been shown to have a wide range of pharmacological effects. In this study, we investigated the therapeutic effects of senegenin on pulmonary fibrosis and their associated mechanisms of action. We found that senegenin inhibited the senescence of epithelial cells and thus exerted anti-pulmonary-fibrosis effects by inhibiting oxidative stress. In addition, we found that senegenin promoted the expression of Sirt1 and Pgc-1α and that the antioxidative and antisenescent effects of senegenin were suppressed by specific silencing of the Sirt1 and Pgc-1α genes, respectively. Moreover, the senegenin-induced effects of antioxidation, antisenescence of epithelial cells, and antifibrosis were inhibited by treatment with Sirt1 inhibitors in vivo. Thus, the Sirt1/Pgc-1α pathway exerts its antifibrotic effect on lung fibrosis by mediating the antioxidative and antisenescent effects of senegenin.

Ultra-sensitive analysis of exhaled biomarkers in ozone-exposed mice via PAI-TOFMS assisted with machine learning algorithms

Ground-level ozone ranks sixth among common air pollutants. It worsens lung diseases like asthma, emphysema, and chronic bronchitis. Despite recent attention from researchers, the link between exhaled breath and ozone-induced injury remains poorly understood. This study aimed to identify novel exhaled biomarkers in ozone-exposed mice using ultra-sensitive photoinduced associative ionization time-of-flight mass spectrometry and machine learning. Distinct ion peaks for acetonitrile (m/z 42, 60, and 78), butyronitrile (m/z 70, 88, and 106), and hydrogen sulfide (m/z 35) were detected. Integration of tissue characteristics, oxidative stress-related mRNA expression, and exhaled breath condensate free-radical analysis enabled a comprehensive exploration of the relationship between ozone-induced biological responses and potential biomarkers. Under similar exposure levels, C57BL/6 mice exhibited pulmonary injury characterized by significant inflammation, oxidative stress, and cardiac damage. Notably, C57BL/6 mice showed free radical signals, indicating a distinct susceptibility profile. Immunodeficient non-obese diabetic Prkdc-/-/Il2rg-/- (NPI) mice exhibited minimal biological responses to pulmonary injury, with little impact on the heart. These findings suggest a divergence in ozone-induced damage pathways in the two mouse types, leading to alterations in exhaled biomarkers. Integrating biomarker discovery with comprehensive biopathological analysis forms a robust foundation for targeted interventions to manage health risks posed by ozone exposure.

Impact of aging on copper isotopic composition in the murine brain

Aging is the main risk factor for Alzheimer's disease (AD). AD is linked to alterations in metal homeostasis and changes in stable metal isotopic composition can occur, possibly allowing the latter to serve as relevant biomarkers for potential AD diagnosis. Copper stable isotopes are used to investigate changes in Cu homeostasis associated with various diseases. Prior work has shown that in AD mouse models, the accumulation of 63Cu in the brain is associated with the disease's progression. However, our understanding of how the normal aging process influences the brain's isotopic composition of copper remains limited. In order to determine the utility and predictive power of Cu isotopes in AD diagnostics, we aim-in this study-to develop a baseline trajectory of Cu isotopic composition in the normally aging mouse brain. We determined the copper concentration and isotopic composition in brains of 30 healthy mice (WT) ranging in age from 6 to 12 mo, and further incorporate prior data obtained for 3-mo-old healthy mice; this range approximately equates to 20-50 yr in human equivalency. A significant 65Cu enrichment has been observed in the 12-mo-old mice compared to the youngest group, concomitant with an increase in Cu concentration with age. Meanwhile, literature data for brains of AD mice display an enrichment in 63Cu isotope compared to WT. It is acutely important that this baseline enrichment in 65Cu is fully constrained and normalized against if any coherent diagnostic observations regarding 63Cu enrichment as a biomarker for AD are to be developed.

Telomeres and the Rate of Living: Linking Biological Clocks of Senescence

AbstractTwo prominent theories of aging, one based on telomere dynamics and the other on mass-specific energy flux, propose biological time clocks of senescence. The relationship between these two theories, and the biological clocks proposed by each, remains unclear. Here, we examine the relationships between telomere shortening rate, mass-specific metabolic rate, and lifespan among vertebrates (mammals, birds, fishes). Results show that telomere shortening rate increases linearly with mass-specific metabolic rate and decreases nonlinearly with increasing body mass in the same way as mass-specific metabolic rate. Results also show that both telomere shortening rate and mass-specific metabolic rate are similarly related to lifespan and that both strongly predict differences in lifespan, although the slopes of the relationships are less than linear. On average, then, telomeres shorten a fixed amount per unit of mass-specific energy flux. So the mitotic clock of telomere shortening and the energetics-based clock described by metabolic rate can be viewed as alternative measures of the same biological clock. These two processes may be linked, we speculate, through the process of cell division.

Effects of Medetomidine-Butorphanol and Medetomidine-Buprenorphine on Oxidative Stress and Vital Parameters in Dogs Undergoing Ovariohysterectomy

Oxidative stress (OS) is caused by an imbalance between the production of oxygen-containing free radicals and their elimination. General anesthesia increases the production of reactive oxygen species (ROS) and therefore causes oxidative stress. Our objective was to determine the effects of medetomidine-butorphanol (MEDBUT) and medetomidine-buprenorphine (MEDBUP) on oxidative stress and cardiorespiratory parameters in dogs undergoing ovariohysterectomy (OHE). Ten healthy female dogs were randomly assigned to two groups: the MEDBUT group (n = 5) received medetomidine and butorphanol, while the MEDBUP group (n = 5) received medetomidine and buprenorphine. OS was evaluated by measuring total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) during five different time points (from the administration of anesthetic drugs to 2 h after surgery). The observed vital cardiorespiratory parameters included heart rate (HR), respiratory rate (fR), noninvasive systolic (SAP) and diastolic (DAP) arterial blood pressures, oxygen saturation (SpO2), end-tidal CO2 (EtCO2), and body temperature (BT). Cardiorespiratory parameters were altered at a significantly greater degree in animals sedated with MEDBUT (p < 0.05). The administration of medetomidine-butorphanol was more likely to increase OS parameters, while medetomidine-buprenorphine showed decreased levels of oxidative stress throughout the study.

Mitochondrial fatty acid beta-oxidation: a possible therapeutic target for skeletal muscle lipotoxicity in peripheral artery disease myopathy

Peripheral artery disease (PAD) is an atherosclerotic disease impacting over 200 million individuals and the prevalence increases with age. PAD occurs when plaque builds up within the peripheral arteries, leading to reduced blood flow and oxygen supply to the outer extremities. Individuals who experience PAD suffer from ischemia, which is typically accompanied by significant damage to skeletal muscles. Additionally, this tissue damage affects mitochondria, causing them to become dysregulated and dysfunctional, resulting in decreased metabolic rates. As there is no known cure for PAD, researchers are exploring potential therapeutic targets by examining coexisting cardiovascular conditions and metabolic risk factors, such as the aging process. Among these comorbidities, type-two diabetes mellitus and obesity are particularly common in PAD cases. These conditions, along with aging itself, are associated with an elevated accumulation of ectopic lipids within skeletal muscles, similar to what is observed in PAD. Researchers have attempted to reduce excess lipid accumulation by increasing the rate of fatty acid beta oxidation. Manipulating acetyl coenzyme A carboxylase 2, a key regulatory protein of fatty acid beta oxidation, has been the primary focus of such research. When acetyl coenzyme A carboxylase 2 is inhibited, it interrupts the conversion of acetyl-CoA into malonyl-CoA, resulting in an increase in the rate of fatty acid beta oxidation. By utilizing samples from PAD patients and applying the pharmacological strategies developed for acetyl coenzyme A carboxylase 2 in diabetes and obesity to PAD, a potential new therapeutic avenue may emerge, offering hope for improved quality of life for individuals suffering from PAD.

The coupling between healthspan and lifespan in Caenorhabditis depends on complex interactions between compound intervention and genetic background

Aging is characterized by declining health that results in decreased cellular resilience and neuromuscular function. The relationship between lifespan and health, and the influence of genetic background on that relationship, has important implications in the development of pharmacological anti-aging interventions. Here we assessed swimming performance as well as survival under thermal and oxidative stress across a nematode genetic diversity test panel to evaluate health effects for three compounds previously studied in the Caenorhabditis Intervention Testing Program and thought to promote longevity in different ways - NP1 (nitrophenyl piperazine-containing compound 1), propyl gallate, and resveratrol. Overall, we find the relationships among median lifespan, oxidative stress resistance, thermotolerance, and mobility vigor to be complex. We show that oxidative stress resistance and thermotolerance vary with compound intervention, genetic background, and age. The effects of tested compounds on swimming locomotion, in contrast, are largely species-specific. In this study, thermotolerance, but not oxidative stress or swimming ability, correlates with lifespan. Notably, some compounds exert strong impact on some health measures without an equally strong impact on lifespan. Our results demonstrate the importance of assessing health and lifespan across genetic backgrounds in the effort to identify reproducible anti-aging interventions, with data underscoring how personalized treatments might be required to optimize health benefits.

Role of Oxidative Stress in Sensorineural Hearing Loss

Hearing is essential for communication, and its loss can cause a serious disruption to one's social life. Hearing loss is also recognized as a major risk factor for dementia; therefore, addressing hearing loss is a pressing global issue. Sensorineural hearing loss, the predominant type of hearing loss, is mainly due to damage to the inner ear along with a variety of pathologies including ischemia, noise, trauma, aging, and ototoxic drugs. In addition to genetic factors, oxidative stress has been identified as a common mechanism underlying several cochlear pathologies. The cochlea, which plays a major role in auditory function, requires high-energy metabolism and is, therefore, highly susceptible to oxidative stress, particularly in the mitochondria. Based on these pathological findings, the potential of antioxidants for the treatment of hearing loss has been demonstrated in several animal studies. However, results from human studies are insufficient, and future clinical trials are required. This review discusses the relationship between sensorineural hearing loss and reactive oxidative species (ROS), with particular emphasis on age-related hearing loss, noise-induced hearing loss, and ischemia-reperfusion injury. Based on these mechanisms, the current status and future perspectives of ROS-targeted therapy for sensorineural hearing loss are described.

Physical frailty trajectories in older stroke survivors: Findings from a national cohort study

BACKGROUND

Physical frailty (PF) is highly prevalent and associated with undesirable outcomes in stroke survivors aged 65 years or older. However, the long-term trajectories of PF are understudied in those older stroke survivors.

AIMS

To identify PF trajectories and relative predictors associated with the PF trajectories in older stroke survivors.

DESIGN

This is a secondary analysis of a population-based cohort study in the United States.

METHODS

Six hundred and sixty-three older stroke survivors from the National Health and Ageing Trends Study from 2015 to 2021 were included. PF was operationally assessed based on the Fried Frailty Phenotype. Trajectories were identified by group-based trajectory modelling. The associations between sociodemographic characteristics, clinical factors, symptoms, cognitive factors and PF trajectories were examined using the design-based logistic regression method.

RESULTS

Most older stroke survivors were 75 and older (63.32%), female (53.99%), white (80.54%) and partnered (50.64%). Two PF trajectory groups were identified (Group 1: low risk, robust; 49.47%; Group 2: high risk, deteriorating; 50.53%). Individuals were at a higher risk to be assigned to Group 2 if they were 75-84 years (adjusted odds ratio [aOR]: 2.16, 95% CI: 1.23-3.80) or 85+ years (aOR: 2.77, 95% CI: 1.52-5.04), had fair self-reported health (aOR: 2.78, 95% CI: 1.53-5.07) or poor self-reported health (aOR: 3.37, 95% CI: 1.51-7.52), had comorbidities (aOR: 8.44, 95% CI: 1.31-54.42), had breathing problems (aOR: 2.18, 95% CI: 1.18-4.02) and had balance problems (aOR: 1.70, 95% CI: 1.06-2.73).

CONCLUSION

PF trajectories in older stroke survivors were heterogeneous and were associated with age, self-rated health status, comorbidities, breathing problems and balance problems.

IMPLICATION TO CLINICAL PRACTICE

Early, routine, dynamic screening for stroke-related physical frailty (PF) and relative predictors might be beneficial for identifying the most vulnerable individuals. Our findings might help develop strategies to manage PF progression.

REPORTING METHOD

The reporting followed the STROBE guideline.

Enhancing lipid peroxidation via radical chain transfer reaction for MRI guided and effective cancer therapy in mice

Lipid peroxidation (LPO), the process of membrane lipid oxidation, is a potential new form of cell death for cancer treatment. However, the radical chain reaction involved in LPO is comprised of the initiation, propagation (the slowest step), and termination stages, limiting its effectiveness in vivo. To address this limitation, we introduce the radical chain transfer reaction into the LPO process to target the propagation step and overcome the sluggish rate of lipid peroxidation, thereby promoting endogenous lipid peroxidation and enhancing therapeutic outcomes. Firstly, radical chain transfer agent (CTA-1)/Fe nanoparticles (CTA-Fe NPs-1) was synthesized. Notably, CTA-1 convert low activity peroxyl radicals (ROO·) into high activity alkoxyl radicals (RO·), creating the cycle of free radical oxidation and increasing the propagation of lipid peroxidation. Additionally, CTA-1/Fe ions enhance reactive oxygen species (ROS) generation, consume glutathione (GSH), and thereby inactivate GPX-4, promoting the initiation stage and reducing termination of free radical reaction. CTA-Fe NPs-1 induce a higher level of peroxidation of polyunsaturated fatty acids in lipid membranes, leading to highly effective treatment in cancer cells. In addition, CTA-Fe NPs-1 could be enriched in tumors inducing potent tumor inhibition and exhibit activatable T1-MRI contrast of magnetic resonance imaging (MRI). In summary, CTA-Fe NPs-1 can enhance intracellular lipid peroxidation by accelerating initiation, propagation, and inhibiting termination step, promoting the cycle of free radical reaction, resulting in effective anticancer outcomes in tumor-bearing mice.

SKN-1/NRF2 upregulation by vitamin A is conserved from nematodes to mammals and is critical for lifespan extension in Caenorhabditis elegans

Vitamin A (VA) is a micronutrient essential for the physiology of many organisms, but its role in longevity and age-related diseases remains unclear. In this work, we used Caenorhabditis elegans to study the impact of various bioactive compounds on lifespan. We demonstrate that VA extends lifespan and reduces lipofuscin and fat accumulation while increasing resistance to heat and oxidative stress. This resistance can be attributed to high levels of detoxifying enzymes called glutathione S-transferases, induced by the transcription factor skinhead-1 (SKN-1). Notably, VA upregulated the transcript levels of skn-1 or its mammalian ortholog NRF2 in both C. elegans, human cells, and liver tissues of mice. Moreover, the loss-of-function genetic models demonstrated a critical involvement of the SKN-1 pathway in longevity extension by VA. Our study thus provides novel insights into the molecular mechanism of anti-aging and anti-oxidative effects of VA, suggesting that this micronutrient could be used for the prevention and/or treatment of age-related disorders.

Cardiovascular benefits of SGLT2 inhibitors and GLP-1 receptor agonists through effects on mitochondrial function and oxidative stress

Overloaded glucose levels in several metabolic diseases such as type 2 diabetes (T2D) can lead to mitochondrial dysfunction and enhanced production of reactive oxygen species (ROS). Oxidative stress and altered mitochondrial homeostasis, particularly in the cardiovascular system, contribute to the development of chronic comorbidities of diabetes. Diabetes-associated hyperglycemia and dyslipidemia can directly damage vascular vessels and lead to coronary artery disease or stroke, and indirectly damage other organs and lead to kidney dysfunction, known as diabetic nephropathy. The new diabetes treatments include Na+-glucose cotransporter 2 inhibitors (iSGLT2) and glucagon-like 1 peptide receptor agonists (GLP-1RA), among others. The iSGLT2 are oral anti-diabetic drugs, whereas GLP-1RA are preferably administered through subcutaneous injection, even though GLP-1RA oral formulations have recently become available. Both therapies are known to improve both carbohydrate and lipid metabolism, as well as to improve cardiovascular and cardiorenal outcomes in diabetic patients. In this review, we present an overview of current knowledge on the relationship between oxidative stress, mitochondrial dysfunction, and cardiovascular therapeutic benefits of iSGLT2 and GLP-1RA. We explore the benefits, limits and common features of the treatments and remark how both are an interesting target in the prevention of obesity, T2D and cardiovascular diseases, and emphasize the lack of a complete understanding of the underlying mechanism of action.

Role of Oxygen and Its Radicals in Peripheral Nerve Regeneration: From Hypoxia to Physoxia to Hyperoxia

Oxygen is compulsory for mitochondrial function and energy supply, but it has numerous more nuanced roles. The different roles of oxygen in peripheral nerve regeneration range from energy supply, inflammation, phagocytosis, and oxidative cell destruction in the context of reperfusion injury to crucial redox signaling cascades that are necessary for effective axonal outgrowth. A fine balance between reactive oxygen species production and antioxidant activity draws the line between physiological and pathological nerve regeneration. There is compelling evidence that redox signaling mediated by the Nox family of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases plays an important role in peripheral nerve regeneration. Further research is needed to better characterize the role of Nox in physiological and pathological circumstances, but the available data suggest that the modulation of Nox activity fosters great therapeutic potential. One of the promising approaches to enhance nerve regeneration by modulating the redox environment is hyperbaric oxygen therapy. In this review, we highlight the influence of various oxygenation states, i.e., hypoxia, physoxia, and hyperoxia, on peripheral nerve repair and regeneration. We summarize the currently available data and knowledge on the effectiveness of using hyperbaric oxygen therapy to treat nerve injuries and discuss future directions.

Effect of 7-ketocholesterol incorporation on substrate binding affinity and turnover rate of the organic cation transporter 2 (OCT2)

The organic cation transporter 2 (OCT2) is pivotal in the renal elimination of several positively charged molecules. OCT2 mode of transport is profoundly influenced by the level of membrane cholesterol. The aim of this study was to investigate the effect of oxidized cholesterol on OCT2 transport activity in human embryonic kidney 293 cells stably transfected with OCT2 (OCT2-HEK293) and in primary renal proximal tubular epithelial cells (RPTEC). Cholesterol was exchanged with 7-ketocholesterol, the main product of cholesterol auto-oxidation, by exposing cells to sterol-saturated methyl-β-cyclodextrin (mβcd). After a 30 min-exposure, approximately 50% of the endogenous cholesterol was replaced by 7-ketocholesterol without significant changes in total sterol level. In the presence of 7-ketocholesterol, [3H]1-methyl-4-phenylpyridinium (MPP+) uptake was significantly reduced in both cell lines. 7-ketocholesterol incorporation did not affect lipid raft integrity, nor OCT2 surface expression and spatial organization. The inhibitory effect of 7-ketocholesterol on MPP+ uptake was abolished by the presence of MPP+ in the trans-compartment. In the presence of 7-ketocholesterol, both Kt and Vmax of MPP+ influx decreased. Molecular docking using OCT2 structure in outward occluded conformation showed overlapping poses and similar binding energies between cholesterol and 7-ketocholesterol. The thermal stability of OCT2 was not changed when cholesterol was replaced with 7-ketocholesterol. We conclude that 7-ketocholesterol confers a higher rigidity to the carrier by reducing its conformational entropy, arguably as a result of changes in plasma membrane physical properties, thereby facilitating the achievement of a higher affinity state at the expense of the mobility and overall cycling rate of the transporter.

Distinguishing between driver and passenger mechanisms of aging

Understanding why we age is a long-standing question, and many mechanistic theories of aging have been proposed. Owing to limitations in studying the aging process, including a lack of adequate quantitative measurements, its mechanistic basis remains a subject of debate. Here, I explore theories of aging from the perspective of causal relationships. Many aging-related changes have been observed and touted as drivers of aging, including molecular changes in the genome, telomeres, mitochondria, epigenome and proteins and cellular changes affecting stem cells, the immune system and senescent cell buildup. Determining which changes are drivers and not passengers of aging remains a challenge, however, and I discuss how animal models and human genetic studies have been used empirically to infer causality. Overall, our understanding of the drivers of human aging is still inadequate; yet with a global aging population, elucidating the causes of aging has the potential to revolutionize biomedical research.

Growth and longevity modulation through larval environment mediate immunosenescence and immune strategy of Tenebrio molitor

BACKGROUND

The Disposable Soma Theory of aging suggests a trade-off between energy allocation for growth, reproduction and somatic maintenance, including immunity. While trade-offs between reproduction and immunity are well documented, those involving growth remain under-explored. Rapid growth might deplete resources, reducing investment in maintenance, potentially leading to earlier or faster senescence and a shorter lifespan. However, rapid growth could limit exposure to parasitism before reaching adulthood, decreasing immunity needs. The insect immunity's components (cellular, enzymatic, and antibacterial) vary in cost, effectiveness, and duration. Despite overall immunity decline (immunosenescence), its components seem to age differently. We hypothesize that investment in these immune components is adjusted based on the resource cost of growth, longevity, and the associated risk of parasitism.

RESULTS

We tested this hypothesis using the mealworm beetle, Tenebrio molitor as our experimental subject. By manipulating the larval environment, including three different temperatures and three relative humidity levels, we achieved a wide range of growth durations and longevities. Our main focus was on the relationship between growth duration, longevity, and specific immune components: hemocyte count, phenoloxidase activity, and antibacterial activity. We measured these immune parameters both before and after exposing the individuals to a standard bacterial immune challenge, enabling us to assess immune responses. These measurements were taken in both young and older adult beetles. Upon altering growth duration and longevity by modifying larval temperature, we observed a more pronounced investment in cellular and antibacterial defenses among individuals with slow growth and extended lifespans. Intriguingly, slower-growing and long-lived beetles exhibited reduced enzymatic activity. Similar results were found when manipulating larval growth duration and adult longevity through variations in relative humidity, with a particular focus on antibacterial activity.

CONCLUSION

The impact of growth manipulation on immune senescence varies by the specific immune parameter under consideration. Yet, in slow-growing T. molitor, a clear decline in cellular and antibacterial immune responses with age was observed. This decline can be linked to their initially stronger immune response in early life. Furthermore, our study suggests an immune strategy favoring enhanced antibacterial activity among slow-growing and long-lived T. molitor individuals.

Association of dietary inflammatory potential, dietary oxidative balance score and biological aging

BACKGROUND & AIMS

The interaction between diet, inflammation, and oxidative stress significantly influences aging, but the available evidence has been limited. We evaluated potential associations of dietary inflammatory index (DII), dietary oxidative balance score (DOBS), and measures of biological aging.

METHODS

This cross-sectional study was performed among 8839 individuals from NHANES 2003-2014. DII and DOBS were determined by aggregating data from 26 to 17 a priori selected dietary components. Biological aging metrics included homeostatic dysregulation (HD), Klemera-Doubal method (KDM), phenotypic age (PA), and allostatic load (AL). Binomial logistic regression models and multivariate linear regression models were conducted.

RESULTS

The associations of dietary inflammation and oxidative stress potential and biological aging metrics were significant among American adults nationwide. Consuming foods with higher DII was significantly associated with accelerated HD 1.26 (1.10, 1.44), KDM 1.24 (1.06, 1.45), and PA 1.54 (1.33, 1.78). Compared with the lowest DOBS, the hazard ratios of accelerated HD, KDM, PA, and AL were 0.74 (0.64, 0.86), 0.80 (0.70, 0.92), 0.61 (0.52, 0.72) and 0.78 (0.63, 0.97), respectively. The adverse effects of pro-inflammatory and pro-oxidative diets on accelerated HD, KDM, and PA were 1.39 (1.18, 1.62), 1.28 (1.08, 1.51), and 1.76 (1.47, 2.10). Serum AST/ALT ratio and globulin were implicated in and mediate the aging effects.

CONCLUSIONS

Higher DII and/or lower DOBS are associated with higher markers of biological aging. Our research elucidates that diets may mitigate biological aging resulting from inflammation and/or oxidative stress.

The Preparation and Effects of Organic-Inorganic Antioxidative Biomaterials for Bone Repair

Reactive oxygen species (ROS) has great influence in many physiological or pathological processes in organisms. In the site of bone defects, the overproduced ROS significantly affects the dynamic balance process of bone regeneration. Many antioxidative organic and inorganic antioxidants showed good osteogenic ability, which has been widely used for bone repair. It is of great significance to summarize the antioxidative bone repair materials (ABRMs) to provide guidance for the future design and preparation of osteogenic materials with antioxidative function. Here, this review introduced the major research direction of ABRM at present in nanoscale, 2-dimensional coating, and 3-dimensional scaffolds. Moreover, the referring main active substances and antioxidative properties were classified, and the positive roles of antioxidative materials for bone repair have also been clearly summarized in signaling pathways, antioxidant enzymes, cellular responses and animal levels.

ROS-scavenging materials for skin wound healing: advancements and applications

The intricate healing process of skin wounds includes a variety of cellular and molecular events. Wound healing heavily relies on reactive oxygen species (ROS), which are essential for controlling various processes, including inflammation, cell growth, angiogenesis, granulation, and the formation of extracellular matrix. Nevertheless, an overabundance of reactive oxygen species (ROS) caused by extended oxidative pressure may result in the postponement or failure of wound healing. It is crucial to comprehend the function of reactive oxygen species (ROS) and create biomaterials that efficiently eliminate ROS to enhance the healing process of skin wounds. In this study, a thorough examination is presented on the role of reactive oxygen species (ROS) in the process of wound healing, along with an exploration of the existing knowledge regarding biomaterials employed for ROS elimination. In addition, the article covers different techniques and substances used in the management of skin wound. The future prospects and clinical applications of enhanced biomaterials are also emphasized, highlighting the potential of biomaterials that scavenge active oxygen to promote skin repair. This article seeks to enhance the understanding of the complex processes of ROS in the healing of wounds and the application of ROS-scavenging materials. Its objective is to create novel strategies for effective treatment skin wounds.

Pharmacological modulation of vascular ageing: A review from VascAgeNet

Vascular ageing, characterized by structural and functional changes in blood vessels of which arterial stiffness and endothelial dysfunction are key components, is associated with increased risk of cardiovascular and other age-related diseases. As the global population continues to age, understanding the underlying mechanisms and developing effective therapeutic interventions to mitigate vascular ageing becomes crucial for improving cardiovascular health outcomes. Therefore, this review provides an overview of the current knowledge on pharmacological modulation of vascular ageing, highlighting key strategies and promising therapeutic targets. Several molecular pathways have been identified as central players in vascular ageing, including oxidative stress and inflammation, the renin-angiotensin-aldosterone system, cellular senescence, macroautophagy, extracellular matrix remodelling, calcification, and gasotransmitter-related signalling. Pharmacological and dietary interventions targeting these pathways have shown potential in ameliorating age-related vascular changes. Nevertheless, the development and application of drugs targeting vascular ageing is complicated by various inherent challenges and limitations, such as certain preclinical methodological considerations, interactions with exercise training and sex/gender-related differences, which should be taken into account. Overall, pharmacological modulation of endothelial dysfunction and arterial stiffness as hallmarks of vascular ageing, holds great promise for improving cardiovascular health in the ageing population. Nonetheless, further research is needed to fully elucidate the underlying mechanisms and optimize the efficacy and safety of these interventions for clinical translation.

Extracts and Scirpusin B from Recycled Seeds and Rinds of Passion Fruits (Passiflora edulis var. Tainung No. 1) Exhibit Improved Functions in Scopolamine-Induced Impaired-Memory ICR Mice

In this paper, the seeds and rinds of passion fruit, which are the agricultural waste of juice processing, were recycled to investigate their biological activities for sustainable use. De-oiled seed powders (S) were successively extracted by refluxing 95% ethanol (95E), 50E, and hot water (HW), respectively, to obtain S-95EE, S-50EE, and S-HWE. Dried rind powders were successively extracted by refluxing HW and 95E to obtain rind-HWE and rind-95EE, respectively. S-50EE and S-95EE showed the most potent extracts, such as anti-amyloid-β1-42 aggregations and anti-acetylcholinesterase inhibitors, and they exhibited neuroprotective activities against amyloid-β25-35-treated or H2O2-treated SH-SY5Y cells. Scirpusin B and piceatannol were identified in S-95EE, S-50EE, and rind-HWE, and they showed anti-acetylcholinesterase activity at 50% inhibitory concentrations of 62.9 and 258.9 μM, respectively. Daily pretreatments of de-oiled seed powders and rind-HWE (600 mg/kg), S-95EE, and S-50EE (250 mg/kg) or scirpusin B (40 mg/kg) for 7 days resulted in improved learning behavior in passive avoidance tests and had significant differences (p < 0.05) compared with those of the control in scopolamine-induced ICR mice. The seeds and rinds of passion fruit will be recycled as materials for the development of functional foods, promoting neuroprotection and delaying the onset of cognitive dysfunctions.

The Ethanolic Extract of Lycium ruthenicum Ameliorates Age-Related Physiological Damage in Mice

Aging and age-related diseases are important study topics due to their associations with progressive physiological damage to genes, cells, tissues, and the entire organism, which ultimately affects the functional efficiency of organs. Lycium ruthenicum Murr. is a functional food that is known for its high contents of anthocyanins and spermidines, both of which have been demonstrated to have positive effects on anti-aging activity and anti-oxidation. In this study, we used HPLC-MS to analyze the constituents of L. ruthenicum Murr. Extract (LRM) and investigated their potential mechanism for exerting antioxidative effects in D-galactose (D-Gal) aging model mice. LRM (25 mg/kg, 50 mg/kg, and 100 mg/kg) improved cognitive function in D-Gal-treated mice, as shown by reduced escape latencies and increased platform crossings in behavioral tests. We measured the contents of lipid peroxidation (LPO) and malondialdehyde (MDA) and the enzyme activities of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in mice serum and brain after 6 weeks of D-Gal treatment. LRM decreased the contents of LPO and MDA and increased the enzyme activities of SOD and GSH-Px, indicating the protection effect of LRM against D-Gal-induced oxidative stress. Additionally, LRM can inhibit oxidative stress in cells by reducing intracellular ROS levels and restoring mitochondrial membrane potential, thereby inhibiting paraquat (PQ)-induced cellular senescence and delaying cell aging. Therefore, LRM has the potential to be a healthcare product for the treatment of age-related diseases.

Acyl-caged rhodamines: photo-controlled and self-calibrated generation of acetyl radicals for neural function recovery in early AD mice

The biological function of radicals is a broad continuum from signaling to killing. Yet, biomedical exploitation of radicals is largely restricted to the theme of healing-by-killing. To explore their potential in healing-by-signaling, robust radical generation methods are warranted. Acyl radicals are endogenous, exhibit facile chemistry and elicit matrix-dependent biological outcomes. Their implications in health and disease remain untapped, primarily due to the lack of a robust generation method with spatiotemporal specificity. Fusing the Norrish chemistry into the xanthene scaffold, we developed a novel general and modular molecular design strategy for photo-triggered generation of acyl radicals, i.e., acyl-caged rhodamine (ACR). A notable feature of ACR is the simultaneous release of a fluorescent probe for cell redox homeostasis allowing real-time monitoring of the biological outcome of acyl radicals. With a donor of the endogenous acetyl radical (ACR575a), we showcased its capability in precise and continuous modulation of the cell redox homeostasis from signaling to stress, and induction of a local oxidative burst to promote differentiation of neural stem cells (NSCs). Upon intracerebral-injection of ACR575a and subsequent fiber-optical activation, early AD mice exhibited enhanced differentiation of NSCs toward neurons, reduced formation of Aβ plaques, and significantly improved cognitive abilities, including learning and memory.

From reactive species to disease development: Effect of oxidants and antioxidants on the cellular biomarkers

The influence of modern lifestyle, diet, exposure to chemicals such as phytosanitary substances, together with sedentary lifestyles and lack of exercise play an important role in inducing reactive stress (RS) and disease. The imbalance in the production and scavenging of free radicals and the induction of RS (oxidative, nitrosative, and halogenative) plays an essential role in the etiology of various chronic pathologies, such as cardiovascular diseases, diabetes, neurodegenerative diseases, and cancer. The implication of free radicals and reactive species injury in metabolic disturbances and the onset of many diseases have been accumulating for several decades, and are now accepted as a major cause of many chronic diseases. Exposure to elevated levels of free radicals can cause molecular structural impact on proteins, lipids, and DNA, as well as functional alteration of enzyme homeostasis, leading to aberrations in gene expression. Endogenous depletion of antioxidant enzymes can be mitigated using exogenous antioxidants. The current interest in the use of exogenous antioxidants as adjunctive agents for the treatment of human diseases allows a better understanding of these diseases, facilitating the development of new therapeutic agents with antioxidant activity to improve the treatment of various diseases. Here we examine the role that RS play in the initiation of disease and in the reactivity of free radicals and RS in organic and inorganic cellular components.

Age-related flexibility of energetic metabolism in the honey bee Apis mellifera

The mechanisms that underpin aging are still elusive. In this study, we suggest that the ability of mitochondria to oxidize different substrates, which is known as metabolic flexibility, is involved in this process. To verify our hypothesis, we used honey bees (Apis mellifera carnica) at different ages, to assess mitochondrial oxygen consumption and enzymatic activities of key enzymes of the energetic metabolism as well as ATP5A1 content (subunit of ATP synthase) and adenylic energy charge (AEC). We also measured mRNA abundance of genes involved in mitochondrial functions and the antioxidant system. Our results demonstrated that mitochondrial respiration increased with age and favored respiration through complexes I and II of the electron transport system (ETS) while glycerol-3-phosphate (G3P) oxidation was relatively decreased. In addition, glycolytic, tricarboxylic acid cycle and ETS enzymatic activities increased, which was associated with higher ATP5A1 content and AEC. Furthermore, we detected an early decrease in the mRNA abundance of subunits of NADH ubiquinone oxidoreductase subunit B2 (NDUFB2, complex I), mitochondrial cytochrome b (CYTB, complex III) of the ETS as well as superoxide dismutase 1 and a later decrease for vitellogenin, catalase and mitochondrial cytochrome c oxidase subunit 1 (COX1, complex IV). Thus, our study suggests that the energetic metabolism is optimized with aging in honey bees, mainly through quantitative and qualitative mitochondrial changes, rather than showing signs of senescence. Moreover, aging modulated metabolic flexibility, which might reflect an underpinning mechanism that explains lifespan disparities between the different castes of worker bees.

Metabolic regulation reduces the oxidative damage of arid lizards in response to moderate heat events

Climate warming poses a significant threat to species worldwide, particularly those inhabiting arid and semi-arid regions where extreme temperatures are increasingly prevalent. However, empirical studies investigating how moderate heat events affect the physiological processes of arid and semi-arid animals are largely scarce. To address this knowledge gap, we used an arid and semi-arid lizard species (Phrynocephalus przewalskii) as a study system. We manipulated thermal environments to simulate moderate heat events (43.5 ± 0.3°C during the heating period) for lizards and examined physiological and biochemical traits related to survival, metabolism, locomotion, oxidative stress, and telomere length. We found that the body condition and survival of the lizards were not significantly affected by moderate heat events, despite an increase in body temperature and a decrease in locomotion at high test temperatures were detected. Mechanistically, we found that the lizards exhibited down-regulated metabolic rates and enhanced activities of antioxidative enzymes, resulting in reduced oxidative damage and stable telomere length under moderate heat events. Based on these findings, which indicated a beneficial regulation of fitness by physiological and biochemical processes, we inferred that moderate heat events did not have a detrimental effect on the toad-headed agama, P. przewalskii. Overall, our research contributes to understanding the impacts of moderate heat events on arid and semi-arid species and highlights the adaptive responses and resilience exhibited by the toad-headed agama in the face of climate warming.

Exercise training upregulates intracellular nicotinamide phosphoribosyltransferase expression in humans: a systematic review with meta-analysis

Objective

Aging is associated with decreased nicotinamide adenine dinucleotide (NAD) levels, which in turn cause dysfunctional mitochondria and indirectly affect a myriad of diseases. Intracellular nicotinamide phosphoribosyltransferase (iNAMPT) serves as a central rate-limiting enzyme in NAD synthesis, making it an indispensable health mediator. This meta-analysis examined the effect of exercise training on the expression of iNAMPT in humans.

Methods

We searched PubMed, Scopus, ClinicalTrials.gov, and the International Clinical Trials Registry Platform for studies published between the inception of the database and July 5, 2023. Using the common-effect model, evidence for the change in iNAMPT following exercise training was synthesized as Cohen's d.

Results

The search yielded five eligible studies. The overall effect size is 0.81, with a 95% confidence interval of 0.55 to 1.07. Therefore, a random adult will have a 71.7% probability that iNAMPT will be up-regulated following exercise training. In general, exercise training resulted in a 1.46-fold increase in iNAMPT. Our probability statistics indicate that subgroups of interest may differ practically. Specifically, there is a 79.3% probability of increased iNAMPT in men, compared to a 69.0% probability in the overall population; young adults have a 75.6% probability of having an increased iNAMPT, whereas aged adults have a 68.7% probability; and, iNAMPT has a 75.1% probability increase after aerobic exercise and a 66.4% probability increase after resistance exercise.

Conclusion

Exercise training is effective for increasing iNAMPT levels in skeletal muscles. This essential enzyme regulates not only cellular energetics but also healthspan. Therefore, exercise should be promoted as a natural slow-aging lifestyle.

The Role of Melatonin to Ameliorate Oxidative Stress in Sperm Cells

It is widely accepted that oxidative stress (OS) coming from a wide variety of causes has detrimental effects on male fertility. Antioxidants could have a significant role in the treatment of male infertility, and the current systematic review on the role of melatonin to ameliorate OS clearly shows that improvement of semen parameters follows melatonin supplementation. Although melatonin has considerable promise, further studies are needed to clarify its ability to preserve or restore semen quality under stress conditions in varied species. The present review examines the actions of melatonin via receptor subtypes and its function in the context of OS across male vertebrates.

Arthrospira platensis Nanoparticles Mitigate Aging-Related Oxidative Injured Brain Induced by D-galactose in Rats Through Antioxidants, Anti-Inflammatory, and MAPK Pathways

Background

Loss of normal function is an inevitable effect of aging. Several factors contribute to the aging process, including cellular senescence and oxidative stress.

Methods

We investigate how Arthrospira platensis Nanoparticles (NSP) protect against aging injury induced by d-galactose (D-gal) in the rat. So, we subcutaneously (S/C) injected D-gal at 200 mg/kg BW to see if Arthrospira platensis Nanoparticles (NSP) might protect against the oxidative changes generated by D-gal. NSP (0.5 mg/kg body weight once daily by gastric gavage) was given to all groups apart from the control and D-gal groups. The d-gal + NSP group was supplemented with 200 mg of D-gal per kg BW once a day and NSP 0.5 mg/kg BW given orally for 45 days. Biochemical, mRNA expression, and histological investigations of brain tissues were used to evaluate the oxidative alterations caused by d-gal and the protective role of NSP.

Results

Our data demonstrated that d-gal was causing significant reductions in relative brain and body weight with increased malondialdehyde (MDA) and redox oxygen species (ROS) levels and increases in serum creatine phosphokinase (CPK) and creatine phosphokinase isoenzyme BB (CPK-BB) with marked decreases in the level of antioxidant enzyme activity in the brain and acetylcholinesterase activity augmented with a phosphorylated H2A histone family member X (γ-H2AX) level increased. The D-gal group had considerably higher phosphorylated p38 mitogen-activated protein kinases (P38MAPK) and C-Jun N-terminal (JNK) kinases. The d-gal administration stimulates the apoptotic gene expression by downregulating the brain superoxide dismutase (SOD), catalase (CAT), and nuclear factor erythroid 2-related factor 2 (Nrf2). The NSP administration saved these parameters in the direction of the control. The brain histopathologic and immunohistochemistry analysis findings support our findings on NSP's protective role.

Conclusion

The NSP may be a promising natural protective compound that can prevent aging and preserve health.

The Role of Oxidative Stress in Multiple Exercise-Regulated Bone Homeostasis

Bone is a tissue that is active throughout the lifespan, and its physiological activities, such as growth, development, absorption, and formation, are always ongoing. All types of stimulation that occur in sports play an important role in regulating the physiological activities of bone. Here, we track the latest research progress locally and abroad, summarize the recent, relevant research results, and systematically summarize the effects of different types of exercise on bone mass, bone strength and bone metabolism. We found that different types of exercise have different effects on bone health due to their unique technical characteristics. Oxidative stress is an important mechanism mediating the exercise regulation of bone homeostasis. Excessive high-intensity exercise does not benefit bone health but induces a high level of oxidative stress in the body, which has a negative impact on bone tissue. Regular moderate exercise can improve the body's antioxidant defense ability, inhibit an excessive oxidative stress response, promote the positive balance of bone metabolism, delay age-related bone loss and deterioration of bone microstructures and have a prevention and treatment effect on osteoporosis caused by many factors. Based on the above findings, we provide evidence for the role of exercise in the prevention and treatment of bone diseases. This study provides a systematic basis for clinicians and professionals to reasonably formulate exercise prescriptions and provides exercise guidance for patients and the general public. This study also provides a reference for follow-up research.

Impact of Aging and Cellular Senescence in the Pathophysiology of Preeclampsia

The incidence of hypertensive disorders of pregnancy is increasing, which may be due to several factors, including an increased age at pregnancy and more comorbid health conditions during reproductive years. Preeclampsia, the most severe hypertensive disorder of pregnancy, has been associated with an increased risk of future disease, including cardiovascular and kidney diseases. Cellular senescence, the process of cell cycle arrest in response to many physiologic and maladaptive stimuli, may play an important role in the pathogenesis of preeclampsia and provide a mechanistic link to future disease. In this article, we will discuss the pathophysiology of preeclampsia, the many mechanisms of cellular senescence, evidence for the involvement of senescence in the development of preeclampsia, as well as evidence that cellular senescence may link preeclampsia to the risk of future disease. Lastly, we will explore how a better understanding of the role of cellular senescence in preeclampsia may lead to therapeutic trials. © 2023 American Physiological Society. Compr Physiol 13:5077-5114, 2023.

Low Antioxidant Glutathione Levels Lead to Longer Telomeres: A Sex-Specific Link to Longevity?

Telomeres are repetitive DNA sequences at the end of chromosomes that protect them from degradation. They have been the focus of intense research because short telomeres would predict accelerated ageing and reduced longevity in vertebrates. Oxidative stress is considered a physiological driver of the telomere shortening and, consequently, short lifespan. Among molecules fighting against oxidative stress, glutathione is involved in many antioxidant pathways. Literature supports that oxidative stress may trigger a compensatory "hormetic" response increasing glutathione levels and telomere length. Here, we tested the link between total glutathione concentration and telomere length in captive birds (zebra finches; Taeniopygia guttata). Total glutathione levels were experimentally decreased during birds' growth using a specific inhibitor of glutathione synthesis (buthionine sulfoximine; BSO). We monitored the birds' reproductive performance in an outdoor aviary during the first month of life, and their longevity for almost 9 years. Among control individuals, erythrocyte glutathione levels during development positively predicted erythrocyte telomere length in adulthood. However, BSO-treated females, but not males, showed longer telomeres than control females in adulthood. This counterintuitive finding suggests that females mounted a compensatory response. Such compensation agrees with precedent findings in the same population where the BSO treatment increased growth and adult body mass in females but not males. BSO did not influence longevity or reproductive output in any sex. However, early glutathione levels and adult telomere length interactively predicted longevity only among control females. Those females with "naturally" low (non-manipulated) glutathione levels at the nestling age but capable of producing longer telomeres in adulthood seem to live longer. The results suggest that the capability to mount a hormetic response triggered by low early glutathione levels can improve fitness via telomere length. Overall, the results may indicate a sex-specific link between glutathione and telomere values. Telomerase activity and sexual steroids (estrogens) are good candidates to explain the sex-biased mechanism underlying the early-life impact of oxidative stress on adult telomere length.

The Unfolded Protein Response: A Double-Edged Sword for Brain Health

Efficient brain function requires as much as 20% of the total oxygen intake to support normal neuronal cell function. This level of oxygen usage, however, leads to the generation of free radicals, and thus can lead to oxidative stress and potentially to age-related cognitive decay and even neurodegenerative diseases. The regulation of this system requires a complex monitoring network to maintain proper oxygen homeostasis. Furthermore, the high content of mitochondria in the brain has elevated glucose demands, and thus requires a normal redox balance. Maintaining this is mediated by adaptive stress response pathways that permit cells to survive oxidative stress and to minimize cellular damage. These stress pathways rely on the proper function of the endoplasmic reticulum (ER) and the activation of the unfolded protein response (UPR), a cellular pathway responsible for normal ER function and cell survival. Interestingly, the UPR has two opposing signaling pathways, one that promotes cell survival and one that induces apoptosis. In this narrative review, we discuss the opposing roles of the UPR signaling pathways and how a better understanding of these stress pathways could potentially allow for the development of effective strategies to prevent age-related cognitive decay as well as treat neurodegenerative diseases.

Age, sex, and apolipoprotein E isoform alter contextual fear learning, neuronal activation, and baseline DNA damage in the hippocampus

Age, female sex, and apolipoprotein E4 (E4) are risk factors to develop Alzheimer's disease (AD). There are three major human apoE isoforms: E2, E3, and E4. Compared to E3, E4 increases while E2 decreases AD risk. However, E2 is associated with increased risk and severity of post-traumatic stress disorder (PTSD). In cognitively healthy adults, E4 carriers have greater brain activation during learning and memory tasks in the absence of behavioral differences. Human apoE targeted replacement (TR) mice display differences in fear extinction that parallel human data: E2 mice show impaired extinction, mirroring heightened PTSD symptoms in E2 combat veterans. Recently, an adaptive role of DNA double strand breaks (DSBs) in immediate early gene expression (IEG) has been described. Age and disease synergistically increase DNA damage and decrease DNA repair. As the mechanisms underlying the relative risks of apoE, sex, and their interactions in aging are unclear, we used young (3 months) and middle-aged (12 months) male and female TR mice to investigate the influence of these factors on DSBs and IEGs at baseline and following contextual fear conditioning. We assessed brain-wide changes in neural activation following fear conditioning using whole-brain cFos imaging in young female TR mice. E4 mice froze more during fear conditioning and had lower cFos immunoreactivity across regions important for somatosensation and contextual encoding compared to E2 mice. E4 mice also showed altered co-activation compared to E3 mice, corresponding to human MRI and cognitive data, and indicating that there are differences in brain activity and connectivity at young ages independent of fear learning. There were increased DSB markers in middle-aged animals and alterations to cFos levels dependent on sex and isoform, as well. The increase in hippocampal DSB markers in middle-aged animals and female E4 mice may play a role in the risk for developing AD.