Overview of Polyamines as Nutrients for Human Healthy Long Life and Effect of Increased Polyamine Intake on DNA Methylation

Polyamine metabolism and anti-tumor immunity

Growing attention has been directed toward the critical role of polyamines in the tumor microenvironment and immune regulation. Polyamines, primarily comprising putrescine, spermidine, and spermine, are tightly regulated through coordinated biosynthesis, catabolism, and transport, with distinct metabolic patterns between normal and cancerous tissues. Emerging evidence highlights the pivotal role of polyamine metabolism in tumor initiation, progression, and metastasis. This review aims to elucidate the differences in polyamine biosynthesis, transport, and catabolism between normal and cancerous tissues, as well as the associated alterations in tumor epigenetic modifications and resistance to immune checkpoint blockade driven by polyamine metabolism. Polyamine metabolism influences both tumor cells and the tumor microenvironment by modulating immune cell phenotypes-shifting them towards either tumor suppression or immune evasion within the tumor immune microenvironment. Additionally, polyamine metabolism impacts immunotherapy through its regulation of key enzymes. This review also explores potential therapeutic targets and summarizes the roles of polyamine inhibitors in combination with immunotherapy for cancer treatment, offering a novel perspective on therapeutic strategies.

AZIN1 level is increased in medulloblastoma and correlates with c-Myc activity and tumor phenotype

BACKGROUND

AZIN1 is a cell cycle regulator that is upregulated in a variety of cancers. AZIN1 overexpression can induce a more aggressive tumor phenotype via increased binding and resultant inhibition of antizyme. Antizyme is a protein that normally functions as an anti-tumor regulator that facilitates the deactivation of several growth-promoting proteins including c-Myc. MYC plays a critical role in medulloblastoma pathogenesis. Its amplification serves as a defining characteristic of group 3 medulloblastomas, associated with the most aggressive clinical course, greater frequency of metastases, and shorter survival times.

METHODS

Medulloblastoma tissues (68 TMA, and 45 fresh tissues, and 31 controls) were stained (fluorescence and immunohistochemical) for AZIN1. Western blotting and ELISA were used to detect the AZIN1 level. Phenotypically aggressive cellular features were measured by increased invasion, colony formation and proliferation. CRISPR-Cas9-mediated AZIN1 knocked-out cells were orthotopically implanted in the cerebellum of nude mice (n = 8/group) with a stereotactic frame. Tumor growth was monitored using the In Vivo Imaging System (IVIS).

RESULTS

Here, we investigated the role of AZIN1 expression in medulloblastoma. We found that overexpression of AZIN1 in medulloblastoma cells induces phenotypically aggressive features. Conducting in vivo studies we found that knocking-out AZIN1 in tumors corresponds with reduced tumor progression and prolonged survival. Clinical specimens are revealing that AZIN1 is highly expressed and directly correlates with MYC amplification status in patients.

CONCLUSION

These data implicate AZIN1 as a putative regulator of medulloblastoma pathogenesis and suggest that it may have clinical application as both a biomarker and novel therapeutic target.

Dietary intake of polyamines in a Spanish adult population: Age-dependent correlation with Healthy Eating Index and Dietary Inflammatory Index scores

OBJECTIVES

A healthy and balanced diet is crucial to maintaining optimal health. Understanding the benefits of different food components is essential. The polyamine spermidine is linked to age-related disease protection, but daily intakes and whether these vary with age are unknown. This study aimed to determine polyamine intake in a Mediterranean diet population and its association with participants' age and Healthy Eating Index (HEI) and Dietary Inflammatory Index (DII) scores.

METHODS

A database was created with references concerning polyamine content in foods to determine the daily intake of foods frequently consumed by 203 participants (84 males and 119 females), ages 18 to 90 y, using a nutritional survey (VioScreen) that includes HEI and DII scores.

RESULTS

The participants' characteristics were as reported in the corresponding 2020 Spanish nutritional survey. Two-thirds demonstrated moderate to high adherence to the Mediterranean diet. The mean HEI score was 74.45 (out of 100), and the mean DII was -1.94 (anti-inflammatory). The median intake of polyamines was 45.59 mg/d/person (mean, 46.89 mg/d/person, 410.57 µmol/d/person), without sex differences. After normalizing the intake per kilocalorie, the Kruskal-Wallis test showed significant differences among age groups for total polyamines ingested, putrescine, and spermidine. The intake of putrescine and spermidine was significantly higher in the 60 to 69 age group compared with the 24 to 59 and 18 to 23 age groups, respectively. HEI scores were positively correlated with polyamine intake, whereas DII scores were negatively correlated.

CONCLUSIONS

Polyamine intake was higher than reported in other populations, did not decrease based on age, and was associated with healthy eating and anti-inflammatory foods.

Arginine metabolism is a biomarker of red blood cell and human aging

Increasing global life expectancy motivates investigations of molecular mechanisms of aging and age-related diseases. This study examines age-associated changes in red blood cells (RBCs), the most numerous host cell in humans. Four cohorts, including healthy individuals and patients with sickle cell disease, were analyzed to define age-dependent changes in RBC metabolism. Over 15,700 specimens from 13,757 humans were examined, a major expansion over previous studies of RBCs in aging. Multi-omics approaches identified chronological age-related alterations in the arginine pathway with increased arginine utilization in RBCs from older individuals. These changes were consistent across healthy and sickle cell disease cohorts and were influenced by genetic variation, sex, and body mass index. Integrating multi-omics data and metabolite quantitative trait loci (mQTL) in humans and 525 diversity outbred mice functionally linked metabolism of arginine during RBC storage to increased vesiculation-a hallmark of RBC aging-and lower post-transfusion hemoglobin increments. Thus, arginine metabolism is a biomarker of RBC and organismal aging, suggesting potential new targets for addressing sequelae of aging.

Tetrahydrobiopterin as a rheostat of cell resistance to oxidant injury

Tetrahydrobiopterin (BH4) deficiency is caused by genetic abnormalities that impair its biosynthesis and recycling, which trigger neurochemical, metabolic, and redox imbalances. Low BH4 levels are also associated with hypoxia, reperfusion reoxygenation, endothelial dysfunction, and other conditions that are not genetically determined. The exact cause of changes in BH4 in nongenetic disorders is not entirely understood, but a role for oxidant species has been implicated. The oxidation of BH4 generates several products, including 7,8-dihydrobiopterin (BH2), the accumulation of which is predicted in cells with low dihydrofolate reductase activity. The relative efficiency of oxidant species at causing variations in BH4/BH2 levels in cells furnished with several antioxidant enzymes has not yet been systematically analyzed. This study examined the quantitative changes of BH4/BH2 in cells challenged with several oxidants. We showed that BH2 is not a major product of treatments with hydrogen peroxide or RSL3, as indicated by the moderate effect of dihydrofolate reductase-inhibitor methotrexate on the accumulation of BH2. However, we found a net loss in BH4/BH2, suggesting that products other than BH2 were generated. These reactions were further examined in NOX4-expressing HEK cells producing hydrogen peroxide. These cells showed slightly decreased BH4/BH2 ratios compared with HEK wild-type cells, and, again, methotrexate treatment moderately increased BH2 levels. In contrast, peroxynitrite-producing RAW 264.7 cells showed dramatically decreased BH4 levels without BH2 accumulation. Following the activation of peroxynitrite production with PMA in lipopolysaccharide-treated cells, we also found a significant time-dependent decline in GTPCH-I protein levels. We conclude that hydrogen peroxide is the least effective oxidant species at decreasing intracellular BH4 levels, while peroxynitrite is highly effective by targeting GTPCH-I and BH4 directly. Moreover, we conclude that BH4/BH2 levels are not a determinant of RSL3 cytotoxicity.

"Enhancing polyamine enrichment from wheat germs: A study utilizing response surface methodology and liquid chromatography-mass spectrometry"

Wheat germ is one of the richest natural sources of polyamines, especially spermidine. Cell proliferation property of polyamines has given them inductive effects in the reduction of a variety of chronic diseases and fertility enhancement. Preparing a polyamine-rich extract powder from wheat germ for use in supplements is the aim of the present study. For the first time, the effects of three independent variables of clean-up replicate (A), extraction time (B), and solid-to-liquid ratio (C) on the response of total spermidine content (Y) were investigated using a central composite design optimizing polyamine enrichment. The optimal extraction conditions were 7 h, 3 clean-up replicates, and 1:4 solid to liquid ratio. This is the first production report of spermidine-enriched powder for encapsulation purposes. To obtain an acceptable rheological property, the polyamine-enriched extract was spray dried together with a selected group of excipients, among which glucose was evidenced as the best choice based on encapsulation properties.

Gut metagenomic features of frailty

This study investigates the relationship between frailty severity and gut microbiome characteristics in adults in Kazakhstan. We analyzed 158 participants across four frailty severity (mild to very severe) using metagenomic sequencing of stool samples. Frailty was significantly correlated with age, weight, and functional measures like walking speed and grip strength. Microbial diversity decreased significantly with increasing frailty. Beta diversity analysis revealed distinct clustering patterns based at phylum level. Taxonomically, we observed a significant inverse correlation between Firmicutes abundance and frailty. Classes like Clostridia and Erysipelotrichia decreased with frailty, while Bacteroidia and Actinobacteria increased. At the family level, Oscillospiraceae showed a positive correlation with frailty. Functionally, we identified significant correlations between frailty measures and specific metabolic pathways. The frailty index negatively correlated with pathways involved in cobalamin, arginine and molybdenum cofactor biosynthesis and positively correlated with folate biosynthesis. Physical performance measures strongly correlated with pathways related to nucleotide biosynthesis, and one-carbon metabolism. We propose these identified features may constitute a "frailty-associated metabolic signature" in the gut microbiome. This signature suggests multiple interconnected mechanisms through which the microbiome may influence frailty development, including modulation of inflammation, alterations in energy metabolism, and potential impacts on muscle function through microbial metabolites.

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

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

Controlled Cultivation Confers Rhodiola rosea Synergistic Activity on Muscle Cell Homeostasis, Metabolism and Antioxidant Defense in Primary Human Myoblasts

Rhodiola rosea L. is recognized for its adaptogenic properties and ability to promote muscle health, function and recovery from exercise. The plethora of biological effects of this plant is ascribed to the synergism existing among the molecules composing its phytocomplex. In this manuscript, we analyze the activity of a bioactive fraction extracted from Rhodiola rosea L. controlled cultivation. Biological assays were performed on human skeletal myoblasts and revealed that the extract is able to modulate in vitro expression of transcription factors, namely Pax7 and myoD, involved in muscle differentiation and recovery. The extract also promotes ROS scavenging, ATP production and mitochondrial respiration. Untargeted metabolomics further reveals that the mechanism underpinning the plant involves the synergistic interconnection between antioxidant enzymes and the folic/acid polyamine pathway. Finally, by examining the phytochemical profiles of the extract, we identify the specific combination of secondary plant metabolites contributing to muscle repair, recovery from stress and regeneration.

Identifying polyamine related biomarkers in diagnosis and treatment of ulcerative colitis by integrating bulk and single-cell sequencing data

Ulcerative colitis (UC) is a chronic inflammatory disorder of the colon, and its pathogenesis remains unclear. Polyamine metabolic enzymes play a crucial role in UC. In this study, we aimed to identify pivotal polyamine-related genes (PRGs) and explore the underlying mechanism between PRGs and the disease status and therapeutic response of UC. We analyzed mRNA-sequencing data and clinical information of UC patients from the GEO database and identified NNMT, PTGS2, TRIM22, TGM2, and PPARG as key PRGs associated with active UC using differential expression analysis and weighted gene co-expression network analysis (WCGNA). Receiver operator characteristic curve (ROC) analysis confirmed the accuracy of these key genes in UC and colitis-associated colon cancer (CAC) diagnosis, and we validated their relationship with therapeutic response in external verification sets. Additionally, single-cell analysis revealed that the key PRGs were specific to certain immune cell types, emphasizing the vital role of intestinal tissue stem cells in active UC. The results were validated in vitro and in vivo experiments, including the colitis mice model and CAC mice model. In conclusion, these key PRGs effectively predict the progression of UC patients and could serve as new pharmacological biomarkers for the therapeutic response of UC.

The Spermine Oxidase/Spermine Axis Coordinates ATG5-Mediated Autophagy to Orchestrate Renal Senescence and Fibrosis

Decreased plasma spermine levels are associated with kidney dysfunction. However, the role of spermine in kidney disease remains largely unknown. Herein, it is demonstrated that spermine oxidase (SMOX), a key enzyme governing polyamine metabolism, is predominantly induced in tubular epithelium of human and mouse fibrotic kidneys, alongside a reduction in renal spermine content in mice. Moreover, renal SMOX expression is positively correlated with kidney fibrosis and function decline in patients with chronic kidney disease. Importantly, supplementation with exogenous spermine or genetically deficient SMOX markedly improves autophagy, reduces senescence, and attenuates fibrosis in mouse kidneys. Further, downregulation of ATG5, a critical component of autophagy, in tubular epithelial cells enhances SMOX expression and reduces spermine in TGF-β1-induced fibrogenesis in vitro and kidney fibrosis in vivo. Mechanically, ATG5 readily interacts with SMOX under physiological conditions and in TGF-β1-induced fibrogenic responses to preserve cellular spermine levels. Collectively, the findings suggest SMOX/spermine axis is a potential novel therapy to antagonize renal fibrosis, possibly by coordinating autophagy and suppressing senescence.

The selective extraction of dietary polyamines from chicken breast using the application of a lab-on-a-chip electromembrane and dispersive liquid-liquid microextraction followed by gas chromatography-mass spectrometry

Excessive dietary polyamines (PAs), including putrescine (PUT), spermine (SPM), and spermidine (SPD), have become a worldwide concern due to their carcinogenicity and reduced shelf life. A modern miniaturized on-chip electromembrane extraction (EME) has been applied to extract these compounds from chicken breast samples. This method is based fundamentally on ionic compounds' electrostatic attraction, diffusion, and solubility in the acceptor phase. The chemical structure of polyamines enables their efficient extraction using an electric driving force on a microchip device. HCl solution (0.1 mol L-1) was applied as an aqueous acceptor solvent. Dispersive liquid-liquid microextraction was performed after EME to facilitate joining three-phase EME to GC-MS and improve the merit figures. The total ranges of 3.77-7.89 μg g-1, 3.48-7.02 μg g-1, and 0.78-2.20 μg g-1 were acquired as PUT, SPM and SPD concentrations in chicken breast, respectively. The results demonstrate that the level of PAs in fresh chicken breast samples is not concerning, but it may reduce the quality of chicken meat over time. This novel analytical technique has several advantages: high recovery, substantial quickness, remarkable selectivity, and good enrichment factors. This emerging method could be generalized to other studies to analyze different foodstuffs.

The potential of short-chain fatty acid epigenetic regulation in chronic low-grade inflammation and obesity

Obesity and chronic low-grade inflammation, often occurring together, significantly contribute to severe metabolic and inflammatory conditions like type 2 diabetes (T2D), cardiovascular disease (CVD), and cancer. A key player is elevated levels of gut dysbiosis-associated lipopolysaccharide (LPS), which disrupts metabolic and immune signaling leading to metabolic endotoxemia, while short-chain fatty acids (SCFAs) beneficially regulate these processes during homeostasis. SCFAs not only safeguard the gut barrier but also exert metabolic and immunomodulatory effects via G protein-coupled receptor binding and epigenetic regulation. SCFAs are emerging as potential agents to counteract dysbiosis-induced epigenetic changes, specifically targeting metabolic and inflammatory genes through DNA methylation, histone acetylation, microRNAs (miRNAs), and long non-coding RNAs (lncRNAs). To assess whether SCFAs can effectively interrupt the detrimental cascade of obesity and inflammation, this review aims to provide a comprehensive overview of the current evidence for their clinical application. The review emphasizes factors influencing SCFA production, the intricate connections between metabolism, the immune system, and the gut microbiome, and the epigenetic mechanisms regulated by SCFAs that impact metabolism and the immune system.

Polyamine Catabolism and Its Role in Renal Injury and Fibrosis in Mice Subjected to Repeated Low-Dose Cisplatin Treatment

Cisplatin, a chemotherapeutic agent, can cause nephrotoxic and ototoxic injuries. Using a mouse model of repeated low dose cisplatin (RLDC), we compared the kidneys of cisplatin- and vehicle-treated mice on days 3 (early injury phase) and 35 (late injury/recovery phase) after the final treatment. RNA-seq analyses revealed increases in the expression of markers of kidney injury (e.g., lipocalin 2 and kidney injury molecule 1) and fibrosis (e.g., collagen 1, fibronectin, and vimentin 1) in RLDC mice. In addition, we observed increased expression of polyamine catabolic enzymes (spermidine/spermine N1-acetyltransferase, Sat1, and spermine oxidase, Smox) and decreased expression of ornithine decarboxylase (Odc1), a rate-limiting enzyme in polyamine synthesis in mice subjected to RLDC. Upon confirmation of the RNA-seq results, we tested the hypothesis that enhanced polyamine catabolism contributes to the onset of renal injury and development of fibrosis. To test our hypothesis, we compared the severity of RLDC-induced renal injury and fibrosis in wildtype (WT), Sat1-KO, and Smox-KO mice. Our results suggest that the ablation of polyamine catabolic enzymes reduces the severity of renal injury and that modulation of the activity of these enzymes may protect against kidney damage and fibrosis caused by cisplatin treatment.

Synergistic antitumor efficacy of gemcitabine and cisplatin to induce ferroptosis in pancreatic ductal adenocarcinoma via Sp1-SAT1-polyamine metabolism pathway

PURPOSE

The combination of cisplatin and gemcitabine-based chemotherapy has been recommended as a preferred regimen for pancreatic ductal adenocarcinoma (PDAC) patients with germline-based mutations. However, the underlying mechanism remains poorly elucidated. Therefore, our study aimed to explore the mechanistic basis of the cell-killing activity of gemcitabine plus cisplatin and identify potential therapeutic targets.

METHODS

First, we explored the synergistic cytotoxic effects of gemcitabine and cisplatin on PDAC through in vitro and in vivo experiments. Then, we investigated ferroptosis-related biomarkers, to assess the impact of the combination therapy on ferroptosis. Using bioinformatics methods, we identified SAT1 as a potential key mediator of ferroptosis induced by gemcitabine and cisplatin. We tested the polyamine levels in PDAC cells by LC-MS after overexpressed or knocked down SAT1, and explored the role of polyamines in ferroptosis using exogenous supplementation. Finally, we explored the regulatory effect of Sp1 on SAT1 through ChIP-qPCR and dual-luciferase reporter assay.

RESULTS

Gemcitabine plus cisplatin enhanced cell death and induced ferroptosis in PDAC. This combination upregulated SAT1 transcription by inhibiting Sp1. SAT1 activation promoted the catabolism of spermine and spermidine, leading to iron accumulation and lipid peroxide generation, ultimately resulting in ferroptosis.

CONCLUSIONS

In summary, our findings suggested the gemcitabine and cisplatin combination therapy induced ferroptosis in a GSH-independent manner in PDAC. The combined treatment inhibited Sp1 and upregulated SAT1 transcription, leading to the breakdown of spermine and spermidine. Therefore, targeting SAT1-induced polyamine metabolism may represent a promising therapeutic strategy for PDAC.

A toxicological assessment of spermidine trihydrochloride produced using an engineered strain of Saccharomyces cerevisiae

Spermidine is a polyamine consumed in the diet, endogenously biosynthesized in most cells, and produced by the intestinal microbiome. A variety of foods contribute to intake of spermidine along with other polyamines. Spermidine trihydrochloride (spermidine-3HCl) of high purity can be produced using an engineered strain of Saccharomyces cerevisiae. Spermidine has a demonstrated history of safe use in the diet; however, limited information is available in the public literature to assess the potential toxicity of spermidine-3HCl. To support a safety assessment for this spermidine-3HCl as a dietary source of spermidine, authoritative guideline and good laboratory practice (GLP) compliant in vitro genotoxicity assays (bacterial reverse mutation and mammalian micronucleus assays) and a 90-day oral (dietary) toxicity study in rats were conducted with spermidine-3HCl. Spermidine-3HCl was non-genotoxic in the in vitro assays, and no adverse effects were reported in the 90-day oral toxicity study up to the highest dose tested, 12500 ppm, equivalent to 728 mg/kg bw/day for males and 829 mg/kg bw/day for females. The subchronic no observed adverse effect level (NOAEL) is 728 mg/kg bw/day.

Cross-sectional analysis of healthy individuals across decades: Aging signatures across multiple physiological compartments

The study of age-related biomarkers from different biofluids and tissues within the same individual might provide a more comprehensive understanding of age-related changes within and between compartments as these changes are likely highly interconnected. Understanding age-related differences by compartments may shed light on the mechanism of their reciprocal interactions, which may contribute to the phenotypic manifestations of aging. To study such possible interactions, we carried out a targeted metabolomic analysis of plasma, skeletal muscle, and urine collected from healthy participants, age 22-92 years, and identified 92, 34, and 35 age-associated metabolites, respectively. The metabolic pathways that were identified across compartments included inflammation and cellular senescence, microbial metabolism, mitochondrial health, sphingolipid metabolism, lysosomal membrane permeabilization, vascular aging, and kidney function.

Anonna crassiflora suppresses colonic carcinogenesis through its antioxidant effects, bioactive amines, and phenol content in rats

Marolo (Annona crassiflora) is an underutilized Brazilian Cerrado fruit with few reports in the literature about its bioactive compounds and functional properties. In this context, the chemoprevention against the carcinogen 1,2-dimethylhydrazine (DMH)-induced pre-neoplastic lesions in Wistar rat colon was investigated and correlated with marolo's antioxidant activity and the contents of phenolic compounds and bioactive amines. Total phenolic compounds (TPC) and total flavonoids compounds (TFC) were determined in the marolo pulp extract by spectrophotometric and Ultra-Performance Liquid Chromatography and diode array detection (UPLC-DAD) analysis. Free bioactive amines were determined by High Performance Liquid Chromatography and fluorescence detection (HPLC-FLD) after post column derivatization with o-phthalaldehyde. In addition, the in vitro antioxidant activity was determined by DPPH, and ABTS. Wistar rats were treated orally with marolo pulp at 0.7, 1.4 and 2.8 g/kg body weight (bw)/day added to a standard ration. Four subcutaneous injections of DMH (40 mg/kg bw) were used to induce a pre-neoplastic lesion that was assessed by the aberrant crypt foci (ACF) assay. The marolo pulp (fresh weigh) showed high content of total phenolic compounds (9.16 mg GAE/g), with predominance of chlorogenic acid (1.86 µg/g) and epicatechin (0.99 µg/g), and total flavonoids (7.26 mg CE/g), ∼85 % of the TPC. The marolo pulp had significant contents of tyramine (31.97 mg/kg), putrescine (20.65 mg/kg), and spermidine (6.32 mg/kg). The marolo pulp inhibited (p < 0.05) pre-neoplastic lesions induced by DMH administration at the all concentrations tested. These findings indicate that marolo pulp has a colon carcinogenesis chemopreventive effect, which could be due to, at least in parts, its antioxidant action associated with its phenolics and flavonoids content as well of spermidine.

Polyamine metabolite spermidine rejuvenates oocyte quality by enhancing mitophagy during female reproductive aging

Advanced age is a primary risk factor for female infertility due to reduced ovarian reserve and declining oocyte quality. However, as an important contributing factor, the role of metabolic regulation during reproductive aging is poorly understood. Here, we applied untargeted metabolomics to identify spermidine as a critical metabolite in ovaries to protect oocytes against aging. In particular, we found that the spermidine level was reduced in ovaries of aged mice and that supplementation with spermidine promoted follicle development, oocyte maturation, early embryonic development and female fertility of aged mice. By microtranscriptomic analysis, we further discovered that spermidine-induced recovery of oocyte quality was mediated by enhancement of mitophagy activity and mitochondrial function in aged mice, and this mechanism of action was conserved in porcine oocytes under oxidative stress. Altogether, our findings suggest that spermidine supplementation could represent a therapeutic strategy to ameliorate oocyte quality and reproductive outcome in cis-gender women and other persons trying to conceive at an advanced age. Future work is needed to test whether this approach can be safely and effectively translated to humans.

Spermidine suppresses oxidative stress and ferroptosis by Nrf2/HO-1/GPX4 and Akt/FHC/ACSL4 pathway to alleviate ovarian damage

AIMS

Oxidative stress is considered to be one of the culprits of ovarian dysfunction. Spermidine (SPD) is a natural aliphatic polyamine that is widely present in living organisms and has been shown to exert preventive effects on various ageing-related diseases. This study seeks to investigate the potential preventive and protective effects of SPD on ovarian oxidative damage.

MAIN METHODS

Ovarian oxidative stress model in C57BL/6 mice was established by 3-nitropropionic acid. Female mice were administrated 10 mg/kg or 15 mg/kg SPD. The estrous cycle, serum hormone levels and mating test were measured to evaluate ovarian function. Follicle counts and AMH levels to assess ovarian reserve. Masson's trichrome to assess ovarian fibrosis. TUNEL analysis to evaluate follicular granulosa cells (GCs) apoptosis. Oxidative stress and autophagy indicators (Nrf2, HO-1, GPX4, LC3B, P62) were measured in vivo and in vitro. RNA-sequencing was performed on SPD-treated GC to study the effects of SPD on Akt and FHC/ACSL4 signaling.

KEY FINDINGS

SPD supplementation improved ovarian endocrine function and reproductive capacity in oxidative stress mice. SPD regularized the estrous cycle and alleviated oxidative stress. Furthermore, SPD increased the ovarian reserve, reducing GC apoptosis by activating the Nrf2/HO-1/GPX4 pathway. RNA-sequencing showed that SPD induced 230 genes changes in porcine GC, which were mainly involved in oocyte meiosis, arginine biosynthesis and glutathione metabolism pathways. SPD attenuated H2O2-induced ferroptosis by regulating Akt/FHC/ACSL4 signaling.

SIGNIFICANCE

SPD alleviates oxidative stress and ferroptosis by regulating the Nrf2/HO-1/GPX4 and Akt/FHC/ACSL4 pathway, which may be a novel potential strategy to protect ovarian oxidative damage.

Changes in Whole Blood Polyamine Levels and Their Background in Age-Related Diseases and Healthy Longevity

The relationship between polyamines and healthy longevity has received much attention in recent years. However, conducting research without understanding the properties of polyamines can lead to unexpected pitfalls. The most fundamental consideration in conducting polyamine studies is that bovine serum used for cell culture contains bovine serum amine oxidase. Bovine serum amine oxidase, which is not inactivated by heat treatment, breaks down spermine and spermidine to produce the highly toxic aldehyde acrolein, which causes cell damage and activates autophagy. However, no such enzyme activity has been found in humans. Polyamine catabolism does not produce toxic aldehydes under normal conditions, but inflammation and some pathogens provoke an inducible enzyme, spermine oxidase, which only breaks down spermine to produce acrolein, resulting in cytotoxicity and the activation of autophagy. Therefore, spermine oxidase activation reduces spermine concentration and the ratio of spermine to spermidine, a feature recently reported in patients with age-related diseases. Spermine, which is increased by a long-term, continuous high polyamine diet, suppresses aberrant gene methylation and the pro-inflammatory status that progress with age and are strongly associated with the development of several age-related diseases and senescence. Changes in spermine concentration and the spermine/spermidine ratio should be considered as indicators of human health status.

Arginine Is a Novel Drug Target for Arginine Decarboxylase in Human Colorectal Cancer Cells

Colorectal cancer (CRC) has been proven to be highly reliant on arginine availability. Limiting arginine-rich foods or treating patients with arginine-depleting enzymes arginine deiminase (ADI) or arginase can suppress colon cancer. However, arginase and ADI are not the best drug candidates for CRC. Ornithine, the product of arginase, can enhance the supply of polyamine, which favors CRC cell growth, while citrulline, the product of ADI, faces the problem of arginine recycling due to the overexpression of argininosuccinate synthetase (ASS). Biosynthetic arginine decarboxylase (ADC), an enzyme that catalyzes the conversion of arginine to agmatine and carbon dioxide, may be a better choice as it combines both arginine depletion and suppression of intracellular polyamine synthesis via its product agmatine. ADC has anti-tumor potential yet has received much less attention than the other two arginine-depleting enzymes. In order to gain a better understanding of ADC, the preparation and the anti-cancer properties of this enzyme were explored in this study. When tested in vitro, ADC inhibited the proliferation of three colorectal cancer cell lines regardless of their ASS cellular expression. In contrast, ADC had a lesser cytotoxic effect on the human foreskin fibroblasts and rat primary hepatocytes. Further in vitro studies revealed that ADC induced S and G2/M phase cell-cycle arrest and apoptosis in HCT116 and LoVo cells. ADC-induced apoptosis in HCT116 cells followed the mitochondrial apoptotic pathway and was caspase-3-dependent. With all results obtained, we suggest that arginine is a potential target for treating colorectal cancer with ADC, and the anti-cancer properties of ADC should be more deeply investigated in the future.

Metabolomics in aging research: aging markers from organs

Metabolism plays an important role in regulating aging at several levels, and metabolic reprogramming is the main driving force of aging. Due to the different metabolic needs of different tissues, the change trend of metabolites during aging in different organs and the influence of different levels of metabolites on organ function are also different, which makes the relationship between the change of metabolite level and aging more complex. However, not all of these changes lead to aging. The development of metabonomics research has opened a door for people to understand the overall changes in the metabolic level in the aging process of organisms. The omics-based "aging clock" of organisms has been established at the level of gene, protein and epigenetic modifications, but there is still no systematic summary at the level of metabolism. Here, we reviewed the relevant research published in the last decade on aging and organ metabolomic changes, discussed several metabolites with high repetition rate, and explained their role in vivo, hoping to find a group of metabolites that can be used as metabolic markers of aging. This information should provide valuable information for future diagnosis or clinical intervention of aging and age-related diseases.

Age-associated polyamines in peripheral blood cells and plasma in 20 to 70 years of age subjects

Dietary polyamines have been associated with slowing ageing processes and various pathologies, raising the importance of establishing reference values at different ages throughout life. This study aimed to analyse age-dependent variations in polyamine content using peripheral blood cells and plasma in a healthy and homogeneous population. Peripheral blood of 193 volunteers of both sexes (20-70 years), selected by convenience, was processed to separate cells and plasma. A pre-column derivatization method was used to determine the amines by HPLC (nmol or pmol/mg protein or nmol/ml) to analyse their association with the age (continuous or ordinal in decades) of the subjects. Putrescine and spermine weakly declined significantly in mononuclear cells with age. In erythrocytes and plasma, putrescine showed an evident decrease in the 60-70-year-old group compared to the rest. The ratios between polyamines, mainly in erythrocytes, decreased in the 60-70 years age group and increased the ratio of putrescine in mononuclear cells/erythrocytes. The ratio of putrescine in mononuclear cells/erythrocytes was higher in the 60-70-year-old age group than in the rest. In a sample of subjects (20-29 vs. 60-70 years), whole blood polyamines were not significantly different when differences existed in erythrocytes. Polyamine homeostasis in blood cells and plasma changed with age. Putrescine declined in mononuclear cells and decreased in erythrocytes and plasma in the decade of the 60 s. Further studies should establish an age-dependent phenotype and whether polyamines' supplementation could restore the decreased values and be associated with long-term overall biological benefits.

Polyamines and Physical Activity in Musculoskeletal Diseases: A Potential Therapeutic Challenge

Autophagy dysregulation is commonplace in the pathogenesis of several invalidating diseases, such as musculoskeletal diseases. Polyamines, as spermidine and spermine, are small aliphatic cations essential for cell growth and differentiation, with multiple antioxidant, anti-inflammatory, and anti-apoptotic effects. Remarkably, they are emerging as natural autophagy regulators with strong anti-aging effects. Polyamine levels were significantly altered in the skeletal muscles of aged animals. Therefore, supplementation of spermine and spermidine may be important to prevent or treat muscle atrophy. Recent in vitro and in vivo experimental studies indicate that spermidine reverses dysfunctional autophagy and stimulates mitophagy in muscles and heart, preventing senescence. Physical exercise, as polyamines, regulates skeletal muscle mass inducing proper autophagy and mitophagy. This narrative review focuses on the latest evidence regarding the efficacy of polyamines and exercise as autophagy inducers, alone or coupled, in alleviating sarcopenia and aging-dependent musculoskeletal diseases. A comprehensive description of overall autophagic steps in muscle, polyamine metabolic pathways, and effects of the role of autophagy inducers played by both polyamines and exercise has been presented. Although literature shows few data in regard to this controversial topic, interesting effects on muscle atrophy in murine models have emerged when the two "autophagy-inducers" were combined. We hope these findings, with caution, can encourage researchers to continue investigating in this direction. In particular, if these novel insights could be confirmed in further in vivo and clinical studies, and the two synergic treatments could be optimized in terms of dose and duration, then polyamine supplementation and physical exercise might have a clinical potential in sarcopenia, and more importantly, implications for a healthy lifestyle in the elderly population.

Carrier-Mediated Process of Putrescine Elimination at the Rat Blood-Retinal Barrier

Putrescine is a bioactive polyamine. Its retinal concentration is strictly controlled to maintain a healthy sense of vision. The present study investigated putrescine transport at the blood-retinal barrier (BRB) to gain a better understanding of the mechanisms of putrescine regulation in the retina. Our microdialysis study showed that the elimination rate constant during the terminal phase was significantly greater (1.90-fold) than that of [¹⁴C]D-mannitol, which is a bulk flow marker. The difference in the apparent elimination rate constants of [³H]putrescine and [¹⁴C]D-mannitol was significantly decreased by unlabeled putrescine and spermine, suggesting active putrescine transport from the retina to the blood across the BRB. Our study using model cell lines of the inner and outer BRB showed that [³H]putrescine transport was time-, temperature-, and concentration-dependent, suggesting the involvement of carrier-mediated processes in putrescine transport at the inner and outer BRB. [³H]Putrescine transport was significantly reduced under Na⁺-free, Cl^--free, and K⁺-replacement conditions, and attenuated by polyamines or organic cations such as choline, a choline transporter-like protein (CTL) substrate. Rat CTL1 cRNA-injected oocytes exhibited marked alterations in [³H]putrescine uptake, and CTL1 knockdown significantly reduced [³H]putrescine uptake in model cell lines, suggesting the possible participation of CTL1 in putrescine transport at the BRB.

Whole Blood Spermine/Spermidine Ratio as a New Indicator of Sarcopenia Status in Older Adults

Early diagnosis and therapeutic intervention improve the quality of life and prognosis of patients with sarcopenia. The natural polyamines spermine and spermidine are involved in many physiological activities. Therefore, we investigated blood polyamine levels as a potential biomarker for sarcopenia. Subjects were Japanese patients >70 years of age who visited outpatient clinics or resided in nursing homes. Sarcopenia was determined based on muscle mass, muscle strength, and physical performance according to the criteria of the Asian Working Group for Sarcopenia (2019). The analysis included 182 patients (male: 38%, age: 83 [76-90] years). Spermidine levels were higher (p = 0.002) and the spermine/spermidine ratio was lower (p < 0.001) in the sarcopenia group than in the non-sarcopenia group. Polyamine concentration analysis showed that the odds ratios for age and spermidine changed in parallel with sarcopenia progression, and the odds ratio for the spermine/spermidine ratio changed inversely with the degree of sarcopenia progression. Additionally, when the odds ratio was analyzed with spermine/spermidine instead of polyamine concentrations, only for spermine/spermidine, the odds ratio values varied in parallel with the progression of sarcopenia. Based on the present data, we believe that the blood spermine/spermidine ratio may be a diagnostic indicator of risk for sarcopenia.

Association of spermidine plasma levels with brain aging in a population-based study

INTRODUCTION

Supplementation with spermidine may support healthy aging, but elevated spermidine tissue levels were shown to be an indicator of Alzheimer's disease (AD).

METHODS

Data from 659 participants (age range: 21-81 years) of the population-based Study of Health in Pomerania TREND were included. We investigated the association between spermidine plasma levels and markers of brain aging (hippocampal volume, AD score, global cortical thickness [CT], and white matter hyperintensities [WMH]).

RESULTS

Higher spermidine levels were significantly associated with lower hippocampal volume (ß = -0.076; 95% confidence interval [CI]: -0.13 to -0.02; q = 0.026), higher AD score (ß = 0.118; 95% CI: 0.05 to 0.19; q = 0.006), lower global CT (ß = -0.104; 95% CI: -0.17 to -0.04; q = 0.014), but not WMH volume. Sensitivity analysis revealed no substantial changes after excluding participants with cancer, depression, or hemolysis.

DISCUSSION

Elevated spermidine plasma levels are associated with advanced brain aging and might serve as potential early biomarker for AD and vascular brain pathology.

Nutritional Factors: Benefits in Glaucoma and Ophthalmologic Pathologies

Glaucoma is a chronic optic neuropathy that can lead to irreversible functional and morphological damage if left untreated. The gold standard therapeutic approaches in managing patients with glaucoma and limiting progression include local drops, laser, and/or surgery, which are all geared at reducing intraocular pressure (IOP). Nutrients, antioxidants, vitamins, organic compounds, and micronutrients have been gaining increasing interest in the past decade as integrative IOP-independent strategies to delay or halt glaucomatous retinal ganglion cell degeneration. In our minireview, we examine the various nutrients and compounds proposed in the current literature for the management of ophthalmology diseases, especially for glaucoma. With respect to each substance considered, this minireview reports the molecular and biological characteristics, neuroprotective activities, antioxidant properties, beneficial mechanisms, and clinical studies published in the past decade in the field of general medicine. This study highlights the potential benefits of these substances in glaucoma and other ophthalmologic pathologies. Nutritional supplementation can thus be useful as integrative IOP-independent strategies in the management of glaucoma and in other ophthalmologic pathologies. Large multicenter clinical trials based on functional and morphologic data collected over long follow-up periods in patients with IOP-independent treatments can pave the way for alternative and/or coadjutant therapeutic options in the management of glaucoma and other ocular pathologies.

Epigenetic modifiers as game changers for healthy ageing

Epigenetic alterations during ageing are manifested with altered gene expression linking it to lifespan regulation, genetic instability, and diseases. Diet and epigenetic modifiers exert a profound effect on the lifespan of an organism by modulating the epigenetic marks. However, our understanding of the multifactorial nature of the epigenetic process during ageing and the onset of disease conditions as well as its reversal by epidrugs, diet, or environmental factors is still mystifying. This review covers the key findings in epigenetics related to ageing and age-related diseases. Further, it holds a discussion about the epigenetic clocks and their implications in various age-related disease conditions including cancer. Although, epigenetics is a reversible process how fast the epigenetic alterations can revert to normal is an intriguing question. Therefore, this paper touches on the possibility of utilizing nutrition and MSCs secretome to accelerate the epigenetic reversal and emphasizes the identification of new therapeutic epigenetic modifiers to counter epigenetic alteration during ageing.

Spermidine dietary supplementation and polyamines level in reference to survival and lifespan of honey bees

Honey bee health has been an important and ongoing topic in recent years. Honey bee is also an important model organism for aging studies. Polyamines, putrescine, spermidine and spermine, are ubiquitous polycations, involved in a wide range of cellular processes such as cell growth, gene regulation, immunity, and regulation of lifespan. Spermidine, named longevity elixir, has been most analysed in the context of aging. One of the several proposed mechanisms behind spermidine actions is antioxidative activity. In present study we showed that dietary spermidine supplementation: (a) improved survival, (b) increased the average lifespan, (c) influenced the content of endogenous polyamines by increasing the level of putrescine and spermidine and decreasing the level of spermine, (d) reduced oxidative stress (MDA level), (e) increased the antioxidant capacity of the organism (FRAP), (f) increased relative gene expression of five genes involved in polyamine metabolism, and (g) upregulated vitellogenin gene in honey bees. To our knowledge, this is the first study on honey bee polyamine levels in reference to their longevity. These results provide important information on possible strategies for improving honey bee health by introducing spermidine into their diet. Here, we offer spermidine concentrations that could be considered for that purpose.

Positive Correlation between Relative Concentration of Spermine to Spermidine in Whole Blood and Skeletal Muscle Mass Index: A Possible Indicator of Sarcopenia and Prognosis of Hemodialysis Patients

Several mechanisms strictly regulate polyamine concentration, and blood polyamines are excreted in urine. This indicates polyamine accumulation in renal dysfunction, and studies have shown increased blood polyamine concentrations in patients with renal failure. Hemodialysis (HD) may compensate for polyamine excretion; however, little is known about polyamine excretion. We measured whole-blood polyamine levels in patients on HD and examined the relationship between polyamine concentrations and indicators associated with health status. Study participants were 59 hemodialysis patients (median age: 70.0 years) at Minami-Uonuma City Hospital and 26 healthy volunteers (median age: 44.5 years). Whole-blood spermidine levels were higher and spermine/spermidine ratio (SPM/SPD) was lower in hemodialysis patients. Hemodialysis showed SPD efflux into the dialysate; however, blood polyamine levels were not altered by hemodialysis and appeared to be minimally excreted. The skeletal muscle mass index (SMI), which was positively correlated with hand grip strength and serum albumin level, was positively correlated with SPM/SPD. Given that sarcopenia and low serum albumin levels are reported risk factors for poor prognosis in HD patients, whole blood SPM/SPD in hemodialysis patients may be a new indicator of the prognosis and health status of HD patients.

Expression of Polyamine Oxidase in Fibroblasts Induces MMP-1 and Decreases the Integrity of Extracellular Matrix

Polyamine oxidase (PAOX) (N¹-acetylpolyamine oxidase) is a major enzyme in the polyamine catabolism pathway that generates hydrogen peroxide. Hydrogen peroxide plays a crucial role in skin aging via extracellular matrix (ECM) degradation by increasing the matrix metalloproteinase-1 (MMP-1) levels. We analyzed the integrity of the ECM in foreskin fibroblasts using PAOX expression. PAOX increased the MMP-1 secretion and type Ι collagen degradation in 2D and 3D cultures of fibroblasts, respectively. Similarly, PAOX overexpression increased the messenger ribonucleic acid (mRNA) level of MMP-1. PAOX expression induced polyamine catabolism, decreased the spermine levels, and increased the putrescine levels. However, the exogenous polyamine treatment did not change the MMP-1 and type I collagen levels as much as PAOX expression. PAOX expression increased the reactive oxygen species (ROS) production in fibroblasts, and exogenous hydrogen peroxide increased both the ROS production and MMP-1 secretion. Furthermore, N-acetylcysteine, an antioxidant, reversed the PAOX-induced ROS production and MMP-1 secretion. PAOX induced the signaling pathways that activate activator protein-1 (AP-1) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which are important transcription factors for MMP-1 transactivation. We concluded that PAOX increased the ROS levels in fibroblasts, leading to an increase in MMP-1 expression. Therefore, we propose that PAOX is a potential target molecule in protecting the ECM integrity.

The influence of nutrition on intestinal disease with emphasis on coccidiosis

Ever since the poultry industry began to intensify early last century, coccidiosis has been a significant problem with which it has had to contend. Losses due to mortality and morbidity can be significant and before the advent of control agents there were several practices, some of which were nutritional, which were implemented to limit these losses. The development of coccidiostats reduced these problems considerably and as a result some of the more extreme intervention measures were no longer necessary. Modern day interpretation of what may have been happening with some of these early interventions provide interesting insights into what may be possible today should cocciodiostats be removed. More recent research has also indicated that the diet has a significant influence on the ability of poultry to resist and resolve an infection through direct and indirect effects on the pathogen, the immune system and on the litter. This paper reviews the role of dietary ingredients and nutrients on the pathogen to establish and the host to resist such an infection. There is clearly no panacea, but the combination of a few practices may reduce the overall challenge experienced by the poultry producer.

Helping the helpers: polyamines help maintain helper T-cell lineage fidelity

The awareness that polyamines play a critical role in immune system regulation and function is coming into focus as the biological systems and analytical tools necessary to evaluate their roles have become available. Puleston et al have recently demonstrated that polyamine metabolism plays a central role in helper T-cell lineage determination through the production of the translational cofactor hypusinated eIF5A and faithful epigenetic regulation through proper histone acetylation. Their findings add to the rapidly growing body of data implicating properly controlled polyamine metabolism as essential for a normally functioning immune system.

The Role of Polyamines in the Mechanisms of Cognitive Impairment

Abstract—As the population ages, age-related cognitive impairments are becoming an increasingly pressing problem. Currently, the role of polyamines (putrescine, spermidine, and spermine) in the pathogenesis of cognitive impairments of various origin is actively discussed. It was shown that the content of polyamines in the brain tissue decreases with age. Exogenous administration of polyamines makes it possible to avoid cognitive impairment and/or influence the pathogenetic processes associated with disease progression. There are 3 known ways that polyamines can enter the human body: food, synthesis by intestinal bacteria, and biosynthesis in the body. Currently, one of the most promising approaches to the prevention of cognitive impairment is the use of foods with a high content of polyamines, as well as the use of various probiotics that affect intestinal bacteria that synthesize polyamines. Since 2018, in a number of European countries projects have been launched aimed at evaluation of the impact of a diet high in polyamines on cognitive processes. The review, based on analysis of modern scientific literature and the authors' own data, presents material on the effect of polyamines on cognitive processes and the role of polyamines in the regulation of neurotransmitter processes, and discusses the role of polyamines in cognitive disorders in mental and neurological diseases.