Polyamines in foods: development of a food database

Biogenic amines as an indicator of rye leaven quality during production and storage

Rye leaven, the basic constituent of sour rye soup ('żurek' or white borsch), was obtained through three methods of initiating lacto-fermentation of rye flour. Optimal concentrations of NaCl (1.5%) and garlic (0.5%) were selected by utilizing the response surface methodology. During the production and storage of leaven at 10 °C and 20 °C, the secalin proteins of rye flour degraded significantly and the concentration of free amino acids increased, making the rye leaven an environment potentially conducive to the formation of biogenic amines. Putrescine (max. conc: 116.7 mg kg-1) and tyramine (max. conc: 63.4 mg kg-1) were the amines that occurred in the largest amounts in the leavens. The final concentration of histamine (after 150 days of storage) did not exceed 22 mg kg-1. Regardless of the method of initiation of fermentation, the products that contained fewer biogenic amines better retained their sensory characteristics (r ≤ -0.89, p < 0.05) and had a higher number of lactic acid bacteria (r ≤ -0.66, p < 0.05).

The potential impact of a vegetarian diet on glaucoma

Treatment of primary open-angle glaucoma has centered on the lowering of intraocular pressure that damages the optic nerve; however, this strategy is not uniformly successful, especially in normal tension glaucoma, and there is interest in antioxidant, anti-inflammatory, and other neuroprotective strategies. Vegetarian diets are known to be rich in antioxidant and anti-inflammatory components and have a number of established health benefits. Thus, it would be reasonable to assume that vegetarian diets would be beneficial in glaucoma, but this approach has not been well studied. We examine the possible role of vegetarian diets and their components in the incidence and progression of glaucoma.

Nutrigenomics of inward rectifier potassium channels

Inwardly rectifying potassium (Kir) channels play a key role in maintaining the resting membrane potential and supporting potassium homeostasis. There are many variants of Kir channels, which are usually tetramers in which the main subunit has two trans-membrane helices attached to two N- and C-terminal cytoplasmic tails with a pore-forming loop in between that contains the selectivity filter. These channels have domains that are strongly modulated by molecules present in nutrients found in different diets, such as phosphoinositols, polyamines and Mg²⁺. These molecules can impact these channels directly or indirectly, either allosterically by modulation of enzymes or via the regulation of channel expression. A particular type of these channels is coupled to cell metabolism and inhibited by ATP (KATP channels, essential for insulin release and for the pathogenesis of metabolic diseases like diabetes mellitus). Genomic changes in Kir channels have a significant impact on metabolism, such as conditioning the nutrients and electrolytes that an individual can take. Thus, the nutrigenomics of ion channels is an important emerging field in which we are attempting to understand how nutrients and diets can affect the activity and expression of ion channels and how genomic changes in such channels may be the basis for pathological conditions that limit nutrition and electrolyte intake. In this contribution we briefly review Kir channels, discuss their nutrigenomics, characterize how different components in the diet affect their function and expression, and suggest how their genomic changes lead to pathological phenotypes that affect diet and electrolyte intake.

High-Dose Spermidine Supplementation Does Not Increase Spermidine Levels in Blood Plasma and Saliva of Healthy Adults: A Randomized Placebo-Controlled Pharmacokinetic and Metabolomic Study

(1) Background: Spermidine is a biogenic polyamine that plays a crucial role in mammalian metabolism. As spermidine levels decline with age, spermidine supplementation is suggested to prevent or delay age-related diseases. However, valid pharmacokinetic data regarding spermidine remains lacking. Therefore, for the first time, the present study investigated the pharmacokinetics of oral spermidine supplementation. (2) Methods: This study was designed as a randomized, placebo-controlled, triple-blinded, two-armed crossover trial with two 5-day intervention phases separated by a washout phase of 9 days. In 12 healthy volunteers, 15 mg/d of spermidine was administered orally, and blood and saliva samples were taken. Spermidine, spermine, and putrescine were quantified by liquid chromatography-mass spectrometry (LC-MS/MS). The plasma metabolome was investigated using nuclear magnetic resonance (NMR) metabolomics. (3) Results: Compared with a placebo, spermidine supplementation significantly increased spermine levels in the plasma, but it did not affect spermidine or putrescine levels. No effect on salivary polyamine concentrations was observed. (4) Conclusions: This study's results suggest that dietary spermidine is presystemically converted into spermine, which then enters systemic circulation. Presumably, the in vitro and clinical effects of spermidine are at least in part attributable to its metabolite, spermine. It is rather unlikely that spermidine supplements with doses <15 mg/d exert any short-term effects.

Mechanisms of spermidine-induced autophagy and geroprotection

Aging involves the systemic deterioration of all known cell types in most eukaryotes. Several recently discovered compounds that extend the healthspan and lifespan of model organisms decelerate pathways that govern the aging process. Among these geroprotectors, spermidine, a natural polyamine ubiquitously found in organisms from all kingdoms, prolongs the lifespan of fungi, nematodes, insects and rodents. In mice, it also postpones the manifestation of various age-associated disorders such as cardiovascular disease and neurodegeneration. The specific features of spermidine, including its presence in common food items, make it an interesting candidate for translational aging research. Here, we review novel insights into the geroprotective mode of action of spermidine at the molecular level, as we discuss strategies for elucidating its clinical potential.

Potential Diets to Improve Mitochondrial Activity in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease, the pathogenesis of which is based on alternations in the mitochondria of motor neurons, causing their progressive death. A growing body of evidence shows that more efficient mitophagy could prevent and/or treat this disorder by suppressing mitochondrial dysfunction-induced oxidative stress and inflammation. Mitophagy has been considered one of the main mechanisms responsible for mitochondrial quality control. Since ALS is characterized by enormous oxidative stress, several edible phytochemicals that can activate mitophagy to remove damaged mitochondria could be considered a promising option to treat ALS by providing neuroprotection. Therefore, it is of great significance to explore the mechanisms of mitophagy in ALS and to understand the effects and/or molecular mechanisms of phytochemical action, which could translate into a treatment for neurodegenerative diseases, including ALS.

A Synthetic Biosensor for Detecting Putrescine in Beef Samples

Biogenic amines (BAs) are toxicological risks present in many food products. Putrescine is the most common foodborne BA and is frequently used as a quality control marker. Currently, there is a lack of regulation concerning safe putrescine limits in food as well as outdated food handling practices leading to unnecessary putrescine intake. Conventional methods used to evaluate BAs in food are generally time-consuming and resource-heavy with few options for on-site analysis. In response to this challenge, we have developed a transcription factor-based biosensor for the quantification of putrescine in beef samples. In this work, we use a naturally occurring putrescine responsive repressor-operator pair (PuuR-puuO) native to Escherichia coli. Moreover, we demonstrate the use of the cell-free putrescine biosensor on a paper-based device that enables rapid low-cost detection of putrescine in beef samples stored at different temperatures. The results presented demonstrate the potential role of using paper-based biosensors for on-site testing, particularly as an index for determining meat product stability and quality.

Changes in Biogenic Amines of Two Table Grapes (cv. Bronx Seedless and Italia) during Berry Development and Ripening

Bronx Seedless and Italia (Vitis vinifera L.) are a variety preferred by consumers owing to their exciting flavour and widely cultivated in Aegean Region in Turkey. The aim was to identify the biogenic amines of these table grapes during berry ripeness. The biogenic amines were analyzed by HPLC in six different berry phenological stages. Italia grapes presented lower biogenic amine content than Bronx Seedless table grapes. The concentration of most of the biogenic amines analyzed linearly raised from the beginning of berry touch to when berries ripen for harvest stages. The most common biogenic amines in grape varieties were putrescine, followed by histamine, agmatine, and tyramine. There was also a positive correlation between all biogenic amines of the two grape varieties. The weakest correlation was found between spermine and cadaverine, whereas the strongest correlation was found among dopamine, trimethylamine, norepinephrine, tyramine, and histamine amines. The present study is the first report of a synthesis study regarding the effect of B.A.s on quality characteristics throughout berry ripeness in grape varieties containing foxy and muscat tastes. The concentration and composition of biogenic amines identified for both varieties might provide helpful information regarding human health and the vintage.

A systematic exploration reveals the potential of spermidine for hypopigmentation treatment through the stabilization of melanogenesis-associated proteins

Spermidine (SPD), a polyamine naturally present in living organisms, is known to prolong the lifespan of animals. In this study, the role of SPD in melanogenesis was investigated, showing potential as a pigmenting agent. SPD treatment increased melanin production in melanocytes in a dose dependent manner. Computational analysis with RNA-sequencing data revealed the alteration of protein degradation by SPD treatment without changes in the expressions of melanogenesis-related genes. Indeed, SPD treatment significantly increased the stabilities of tyrosinase-related protein (TRP)-1 and -2 while inhibiting ubiquitination, which was confirmed by treatment of proteasome inhibitor MG132. Inhibition of protein synthesis by cycloheximide (CHX) showed that SPD treatment increased the resistance of TRP-1 and TRP-2 to protein degradation. To identify the proteins involved in SPD transportation in melanocytes, the expression of several solute carrier (SLC) membrane transporters was assessed and, among 27 transporter genes, SLC3A2, SLC7A1, SLC18B1, and SLC22A18 were highly expressed, implying they are putative SPD transporters in melanocytes. Furthermore, SLC7A1 and SLC22A18 were downregulated by SPD treatment, indicating their active involvement in polyamine homeostasis. Finally, we applied SPD to a human skin equivalent and observed elevated melanin production. Our results identify SPD as a potential natural product to alleviate hypopigmentation.

Antiaging agents: safe interventions to slow aging and healthy life span extension

Human longevity has increased dramatically during the past century. More than 20% of the 9 billion population of the world will exceed the age of 60 in 2050. Since the last three decades, some interventions and many preclinical studies have been found to show slowing aging and increasing the healthy lifespan of organisms from yeast, flies, rodents to nonhuman primates. The interventions are classified into two groups: lifestyle modifications and pharmacological/genetic manipulations. Some genetic pathways have been characterized to have a specific role in controlling aging and lifespan. Thus, all genes in the pathways are potential antiaging targets. Currently, many antiaging compounds target the calorie-restriction mimetic, autophagy induction, and putative enhancement of cell regeneration, epigenetic modulation of gene activity such as inhibition of histone deacetylases and DNA methyltransferases, are under development. It appears evident that the exploration of new targets for these antiaging agents based on biogerontological research provides an incredible opportunity for the healthcare and pharmaceutical industries. The present review focus on the properties of slow aging and healthy life span extension of natural products from various biological resources, endogenous substances, drugs, and synthetic compounds, as well as the mechanisms of targets for antiaging evaluation. These bioactive compounds that could benefit healthy aging and the potential role of life span extension are discussed.

Safety and Quality of Canned Sardines after Opening: A Shelf-Stability Study

This study aimed to define the shelf life of canned sardines after opening to increase consumer awareness of their quality and safety and reduce food waste. For this purpose, canned sardines (Sardina pilchardus) packed with different sauces were opened and stored at 4 °C for 7 days. Microbiological, sensorial, physical and chemical stability was monitored daily by standard methodologies. Results show that the overall quality and safety are highly dependent on the sauce type. To preserve their full quality, sardines in brine and in vegetable oil should be consumed up to 1 day after opening, while sardines in tomato sauce were stable for up to 3 days, although none were considered nonedible up to the 7th day. Many parameters demonstrated statistical differences and correlations with storage, although they were not as decisive as sensory evaluation. This integrated approach should be adopted by the food industry and regulating authorities to provide information to consumers regarding the quality and safety of handled goods.

Unique Chemistry, Intake, and Metabolism of Polyamines in the Central Nervous System (CNS) and Its Body

Polyamines (PAs) are small, versatile molecules with two or more nitrogen-containing positively charged groups and provide widespread biological functions. Most of these aspects are well known and covered by quite a number of excellent surveys. Here, the present review includes novel aspects and questions: (1) It summarizes the role of most natural and some important synthetic PAs. (2) It depicts PA uptake from nutrition and bacterial production in the intestinal system following loss of PAs via defecation. (3) It highlights the discrepancy between the high concentrations of PAs in the gut lumen and their low concentration in the blood plasma and cerebrospinal fluid, while concentrations in cellular cytoplasm are much higher. (4) The present review provides a novel and complete scheme for the biosynthesis of Pas, including glycine, glutamate, proline and others as PA precursors, and provides a hypothesis that the agmatine pathway may rescue putrescine production when ODC knockout seems to be lethal (solving the apparent contradiction in the literature). (5) It summarizes novel data on PA transport in brain glial cells explaining why these cells but not neurons preferentially accumulate PAs. (6) Finally, it provides a novel and complete scheme for PA interconversion, including hypusine, putreanine, and GABA (unique gliotransmitter) as end-products. Altogether, this review can serve as an updated contribution to understanding the PA mystery.

Docosahexaenoic Acid-Enhanced Autophagic Flux Improves Cardiac Dysfunction after Myocardial Infarction by Targeting the AMPK/mTOR Signaling Pathway

Background and Purpose. Docosahexaenoic acid (DHA) is a type of polyunsaturated fatty acid enriched in cod liver oil and seaweed. It is necessary for the human body and has important functions, such as antioxidation and antiatherosclerosis activities. Long-term oral administration of DHA or the use of DHA at the initial stage of ischemia can increase the level of autophagy and exert a protective effect on neurological functions related to cerebral infarction. However, the effect of DHA on myocardial injury and cardiac insufficiency after myocardial infarction (MI) is unknown. This study was aimed at exploring whether DHA plays a protective role in AMI and its specific molecular mechanism. Experimental Method. In vitro cardiomyocyte hypoxia and in vivo MI injury models were used to determine the role of DHA in MI. Hypoxic injury induced damage in cultured neonatal mouse cardiomyocytes (NMCs). The C57BL/6J mouse MI model was established by permanent ligation of the left anterior descending branch. Main Results. DHA improved the cardiomyocyte viability of NMCs induced by hypoxia injury and reduced cell necrosis. DHA reduced infarct size, improved heart function, and reduced the degree of myocardial fibrosis in mice after MI. In addition, DHA enhanced autophagy flux and reduced apoptosis in vitro and in vivo. In addition, we found that chloroquine, an autophagy inhibitor, blocked the protective effect of DHA on cardiomyocyte apoptosis and cardiac dysfunction, indicating that DHA exerts cardioprotective effects in part by promoting autophagy flux. We also observed that DHA enhanced autophagy flux by activating the AMPK/mTOR signaling pathway. Conclusions and Significance. In conclusion, our findings indicate for the first time that DHA improves MI-induced cardiac dysfunction by promoting AMPK/mTOR-mediated autophagic flux.

Vaginal microbiota of American Indian women and associations with measures of psychosocial stress

Molecular-bacterial vaginosis (BV) is characterized by low levels of vaginal Lactobacillus species and is associated with higher risk of sexually transmitted infections (STI). Perceived psychosocial stress is associated with increased severity and persistence of infections, including STIs. American Indians have the highest rates of stress and high rates of STIs. The prevalence of molecular-BV among American Indian women is unknown. We sought to evaluate measures of psychosocial stress, such as historic loss (a multigenerational factor involving slavery, forced removal from one's land, legally ratified race-based segregation, and contemporary discrimination) and their association with the vaginal microbiota and specific metabolites associated with BV, in 70 Northwestern Plains American Indian women. Demographics, perceived psychosocial stressors, sexual practices, and known BV risk factors were assessed using a modified version of the American Indian Service Utilization, Psychiatric Epidemiology, Risk and Protective Factors Project survey. Self-collected mid-vaginal swabs were profiled for bacterial composition by 16S rRNA gene amplicon sequencing and metabolites quantified by targeted liquid-chromatography mass spectrometry. Sixty-six percent of the participants were classified as having molecular-BV, with the rest being either dominated by L. crispatus (10%) or L. iners (24%). High levels of lifetime trauma were associated with higher odds of having molecular-BV (adjusted Odds Ratio (aOR): 2.5, 95% Credible Interval (CrI): 1.1-5.3). Measures of psychosocial stress, including historic loss and historic loss associated symptoms, were significantly associated with lifestyle and behavioral practices. Higher scores of lifetime trauma were associated with increased concentrations of spermine (aFC: 3.3, 95% CrI: 1.2-9.2). Historic loss associated symptoms and biogenic amines were the major correlates of molecular-BV. Historical loss associated symptoms and lifetime trauma are potentially important underlying factors associated with BV.

Accumulation and Transformation of Biogenic Amines and Gamma-Aminobutyric Acid (GABA) in Chickpea Sourdough

In general, sourdough fermentation leads to an improvement in the technological, nutritional, and sensory properties of bakery products. The use of non-conventional flours with a specific autochthonous microbiota may lead to the formation of secondary metabolites, which may even have undesirable physiological and toxicological effects. Chickpea flours from different suppliers have been used to produce sourdoughs by spontaneous and inoculated fermentations. The content of nutritionally undesirable biogenic amines (BA) and beneficial gamma-aminobutyric acid (GABA) was determined by chromatography. Fenugreek sprouts, which are a rich source of amine oxidases, were used to reduce the BA content in the sourdoughs. Spontaneous fermentation resulted in a high accumulation of cadaverine, putrescine, and tyramine for certain flours. The use of commercial starter cultures was not effective in reducing the accumulation of BA in all sourdoughs. The addition of fenugreek sprouts to the suspension of sourdough with pH raised to 6.5 resulted in a significant reduction in BA contents. Enzymatic oxidation was less efficient during kneading. Baking resulted in only a partial degradation of BA and GABA in the crust and not in the crumb. Therefore, it could be suggested to give more importance to the control of sourdough fermentation with regard to the formation of nutritionally undesirable BA and to exploit the possibilities of their degradation.

Oral Spermidine Targets Brown Fat and Skeletal Muscle to Mitigate Diet-Induced Obesity and Metabolic Disorders

INTRODUCTION

Obesity causes many life-threatening diseases. It is important to develop effective approaches for obesity treatment. Oral supplementation with spermidine retards age-related processes, but its influences on obesity and various metabolic tissues remain largely unknow. This study aims to investigate the effects of oral spermidine on brown adipose tissue (BAT) and skeletal muscle as well as its roles in counteracting obesity and metabolic disorders.

METHODS AND RESULTS

Spermidine is orally administrated into high-fat diet (HFD)-fed mice. The weight gain, insulin resistance, and hepatic steatosis are attenuated by oral spermidine in HFD-fed mice, accompanied by an alleviation of white adipose tissue inflammation. Oral spermidine promotes BAT activation and metabolic adaptation of skeletal muscle in HFD-fed mice, evidenced by UCP-1 induction and CREB activation in both tissues. Notably, oral spermidine upregulates tyrosine hydroxylase in hypothalamus of HFD-fed mice; spermidine treatment increases tyrosine hydroxylase expression and norepinephrine production in neurocytes, which leads to CREB activation and UCP-1 induction in brown adipocytes and myotubes. Spermidine also directly promotes UCP-1 and PGC-1α expression in brown adipocytes and myotubes.

CONCLUSION

Spermidine serves as an oral supplement to attenuate obesity and metabolic disorders through hypothalamus-dependent or -independent BAT activation and skeletal muscle adaptation.

Natural Contaminants in Wines: Determination of Biogenic Amines by Chromatographic Techniques

Biogenic amines (BAs) are natural contaminants of wine that originate from decarboxylase microorganisms involved in fermentation processes. The primary relevance of biogenic amines in food could have both toxic effects on consumers’ health (i.e., allergic reactions, nausea, tremors, etc.), if present at high concentrations, and concurrently it can be considered as a remarkable indicator of quality and/or freshness. Therefore, the presence of nine biogenic amines [Tryptamine (TRP), ß-phenylethylamine (ß-PEA), putrescine (PUT), cadaverine (CAD), histamine (HIS), serotonin (SER), tyramine (TYR), spermidine (SPD), and spermine (SPM)] was investigated in red and white wine samples, which differed in the winemaking processes. The qualitative-quantitative determination of BAs was carried out by chromatographic methods (HPLC-UV/Vis and LC-ESI-MS). The analysis showed that both winemaking processes had all the nine BAs considered in the study at different amounts. Data showed that red wines had a higher concentration of PUT (10.52 mg L⁻¹), TYR (7.57 mg L⁻¹), and HIS (6.5 mg L⁻¹), the BAs most involved in food poisoning, compared to white wines, probably related to the different type of fermentation (alcoholic and malolactic).

Caloric Restriction Mimetics in Nutrition and Clinical Trials

The human diet and dietary patterns are closely linked to the health status. High-calorie Western-style diets have increasingly come under scrutiny as their caloric load and composition contribute to the development of non-communicable diseases, such as diabetes, cancer, obesity, and cardiovascular disorders. On the other hand, calorie-reduced and health-promoting diets have shown promising results in maintaining health and reducing disease burden throughout aging. More recently, pharmacological Caloric Restriction Mimetics (CRMs) have gained interest of the public and scientific community as promising candidates that mimic some of the myriad of effects induced by caloric restriction. Importantly, many of the CRM candidates activate autophagy, prolong life- and healthspan in model organisms and ameliorate diverse disease symptoms without the need to cut calories. Among others, glycolytic inhibitors (e.g., D-allulose, D-glucosamine), hydroxycitric acid, NAD+ precursors, polyamines (e.g., spermidine), polyphenols (e.g., resveratrol, dimethoxychalcones, curcumin, EGCG, quercetin) and salicylic acid qualify as CRM candidates, which are naturally available via foods and beverages. However, it is yet unclear how these bioactive substances contribute to the benefits of healthy diets. In this review, we thus discuss dietary sources, availability and intake levels of dietary CRMs. Finally, since translational research on CRMs has entered the clinical stage, we provide a summary of their effects in clinical trials.

Spermidine and spermine exert protective effects within the lung

Asthma is a heterologous disease that is influenced by complex interactions between multiple environmental exposures, metabolism, and host immunoregulatory processes. Specific metabolites are increasingly recognized to influence respiratory inflammation. However, the role of protein-derived metabolites in regulating inflammatory responses in the lung are poorly described. The aims of the present study were to quantify polyamine levels in bronchoalveolar lavages (BALs) from healthy volunteers and asthma patients, and to evaluate the impact of each polyamine on inflammatory responses using in vitro models and in a house dust mite (HDM)-induced respiratory allergy model. Spermidine levels were decreased, while cadaverine levels were increased in BALs from asthma patients compared to healthy controls, using Ultra Performance Liquid Chromatography (UPLC). Both spermine and spermidine inhibit lipopolysaccharide (LPS)-induced cytokine secretion from human peripheral blood mononuclear cells (PBMCs) and dendritic cells (DCs) in vitro. In addition, oral gavage with spermine or spermidine modulate HDM-induced cell infiltration, cytokine secretion, and epithelial cell tight junction expression in murine models. Spermidine also reduces airway hyper-responsiveness. These results suggest that modulation of polyamine metabolism, in particular spermidine, is associated with respiratory inflammation and these molecules and pathways should be further explored as biomarkers of disease and potential targets for novel therapies.

Natural compounds modulate the autophagy with potential implication of stroke

Stroke is considered a leading cause of mortality and neurological disability, which puts a huge burden on individuals and the community. To date, effective therapy for stroke has been limited by its complex pathological mechanisms. Autophagy refers to an intracellular degrading process with the involvement of lysosomes. Autophagy plays a critical role in maintaining the homeostasis and survival of cells by eliminating damaged or non-essential cellular constituents. Increasing evidence support that autophagy protects neuronal cells from ischemic injury. However, under certain circumstances, autophagy activation induces cell death and aggravates ischemic brain injury. Diverse naturally derived compounds have been found to modulate autophagy and exert neuroprotection against stroke. In the present work, we have reviewed recent advances in naturally derived compounds that regulate autophagy and discussed their potential application in stroke treatment.

The metabolic role of spermidine in obesity: Evidence from cells to community

Spermidine is a natural polyamine existing in all living cells known to play an important role in cellular functions. Recently, several studies have reported the effect of alterations in the spermidine pool on metabolic pathways. It has been shown that activation of spermidine/spermine N-1-acetyl-transferase (SSAT), the rate-limiting enzyme in polyamine catabolism, improved glucose and lipid metabolism. In addition, spermidine supplementation has been shown to protect against diet-induced obesity in animal models. However, some clinical studies demonstrated that polyamine levels are increased in childhood obesity and metabolic syndrome patients with type 2 diabetes (T2DM), while polyamine-rich food is associated with a lower incidence of cardiovascular disease (CVD). Therefore, this review aims to summarize and discuss the evidence from in vitro, in vivo and clinical studies on the possible roles of spermidine on metabolic pathways under physiological and obese conditions. All consistent and inconsistent findings are discussed and further studies aiming to fill any gaps in the knowledge are proposed.

Polyamines: Functions, Metabolism, and Role in Human Disease Management

Putrescine, spermine, and spermidine are the important polyamines (PAs), found in all living organisms. PAs are formed by the decarboxylation of amino acids, and they facilitate cell growth and development via different cellular responses. PAs are the integrated part of the cellular and genetic metabolism and help in transcription, translation, signaling, and post-translational modifications. At the cellular level, PA concentration may influence the condition of various diseases in the body. For instance, a high PA level is detrimental to patients suffering from aging, cognitive impairment, and cancer. The levels of PAs decline with age in humans, which is associated with different health disorders. On the other hand, PAs reduce the risk of many cardiovascular diseases and increase longevity, when taken in an optimum quantity. Therefore, a controlled diet is an easy way to maintain the level of PAs in the body. Based on the nutritional intake of PAs, healthy cell functioning can be maintained. Moreover, several diseases can also be controlled to a higher extend via maintaining the metabolism of PAs. The present review discusses the types, important functions, and metabolism of PAs in humans. It also highlights the nutritional role of PAs in the prevention of various diseases.

Kokumi taste perception is functional in a model carnivore, the domestic cat (Felis catus)

Kokumi taste is a well-accepted and characterised taste modality and is described as a sensation of enhancement of sweet, salty, and umami tastes. The Calcium Sensing Receptor (CaSR) has been designated as the putative kokumi taste receptor for humans, and a number of kokumi-active ligands of CaSR have been discovered recently with activity confirmed both in vivo and in vitro. Domestic cats (Felis catus) are obligate carnivores and accordingly, their diet is abundant in proteins, peptides, and amino acids. We hypothesised that CaSR is a key taste receptor for carnivores, due to its role in the detection of different peptides and amino acids in other species. Using in silico, in vitro and in vivo approaches, here we compare human CaSR to that of a model carnivore, the domestic cat. We found broad similarities in ligand specificity, but differences in taste sensitivity between the two species. Indeed our in vivo data shows that cats are sensitive to CaCl₂ as a kokumi compound, but don't show this same activity with Glutathione, whereas for humans the reverse is true. Collectively, our data suggest that kokumi is an important taste modality for carnivores that drives the palatability of meat-derived compounds such as amino acids and peptides, and that there are differences in the perception of kokumi taste between carnivores and omnivores.

Effects of "fresh mechanically deboned meat" inclusion on nutritional value, palatability, shelf-life microbiological risk and digestibility in dry dog food

Fresh mechanically deboned meat (MDM) is usually claimed as high-quality ingredient on dry pet food recipes and this aspect may positively influence consumer choice. It is important to determine the scientifically sustainability of this claim and to assess the microbiological safety of MDM inclusion in dry pet food. Objectives were: 1) to evaluate the effect of inclusion of MDM in dry dog food on fatty acid profile and in vivo and in vitro digestibility, proposing a new system (Daisy^II Incubator) to measure the in vitro digestibility for dogs; 2) to compare palatability of dry dog food containing MDM with dry dog food in which meat by-products (MBP) are the only animal protein sources; 3) to determine, whether or not, the inclusion of that ingredient changes the microbiology and the storage quality. Results indicated that MDM product was characterized by significant higher nutritional value in terms of fatty acids profile, in vitro digestibility (HV-IVD method) and lower palatability than the MBP product. Microbiological risk assessment showed no microbiological hazards for either product. After 6-months storage, the total mesophilic bacterial count ranged between 1.77 and 2.09 log CFU/g feed, while polyamine values were higher in the MDM (0.37 g/kg) than in the MBP (0.27 g/kg). The Daisy^II Incubator was found to be a valid instrument for studying in vitro digestibility also for dogs, providing data simply, quickly, with less variability and costs than in vivo trials. In conclusion, MDM inclusion in dry dog food is microbiologically safe and it can improve its nutritional quality, at the expense of a reduced palatability. The higher polyamine levels fount in MDM-enriched petfood after 6-months storage, however, may represent a possible hazard, and further studies are still warranted.

Spermidine Prevents Ethanol and Lipopolysaccharide-Induced Hepatic Injury in Mice

To date, there is no effective treatment for alcoholic liver disease, despite its prevalence world-wide. Because alcohol consumption is associated with oxidative stress-induced liver injury and pro-inflammatory responses, naturally occurring antioxidants and/or anti-inflammatories may be potential therapeutics. Spermidine is an abundant, ubiquitous polyamine that has been found to display strong antioxidant and anti-inflammatory properties. To further investigate whether spermidine is an effective intervention for alcohol-induced liver disease, we examined its hepatoprotective properties using a two-hit, chronic ethanol and acute lipopolysaccharide (LPS)-induced mouse model of liver injury. We determined that spermidine administration prevented ethanol and LPS-induced increases in liver injury using plasma ALT as a readout. Furthermore, histological analysis of tissue from control and treated animals revealed that the pathology associated with ethanol and LPS treatment was prevented in mice additionally treated with spermidine. As predicted, spermidine also prevented ethanol and LPS-induced oxidative stress by decreasing the levels of both reactive oxygen species (ROS) and lipid peroxidation. We further determined that spermidine treatment prevented the nuclear translocation of nuclear factor κB (NFκB) by blocking the phosphorylation of the inhibitory protein, IκB, thereby preventing expression of pro-inflammatory cytokines. Finally, by measuring expression of known markers of hepatic stellate cell activation and monitoring collagen deposition, we observed that spermidine also prevented alcohol and LPS-induced hepatic fibrosis. Together, our results indicate that spermidine is an antioxidant thereby conferring anti-inflammatory and anti-fibrotic effects associated with alcoholic liver injury.

Merging Heat Stress Tolerance and Health-Promoting Properties: The Effects of Exogenous Arginine in Cauliflower (Brassica oleracea var. botrytis L.)

In the last decades, cauliflower consumption has increased due to its observed beneficial effects on human health, especially on chronic diseases. Furthermore, the use of arginine has been shown to improve the heat stress tolerance of plants by increasing the polyamine content. Thus, we aimed to investigate the effects of the exogenous application of arginine on the physical and chemical quality parameters of cauliflower florets under heat stress. For this, we applied two concentrations of arginine (1 and 4 mM) to the leaves of cauliflower (Brassica oleracea var. botrytis L.) plants grown in three different temperatures (ambient, elevated, and extreme). Our data show that potassium and phosphate, as well as iron were the most abundant macro- and micronutrients, respectively. The combination of high temperature and exogenous application of arginine increased the antioxidant activity, total content of phenolic compounds, polyamines, and proteins. The data presented herein indicate that the combination of an adequate heat stress and the appropriate foliar arginine treatment may be a useful strategy that could be used to increase the number of valuable plant compounds in our diet.

Spermidine endows macrophages anti-inflammatory properties by inducing mitochondrial superoxide-dependent AMPK activation, Hif-1α upregulation and autophagy

Distinct metabolic programs, either energy-consuming anabolism or energy-generating catabolism, were required for different biological functions. Macrophages can adopt different immune phenotypes in response to various cues and exhibit anti- or pro-inflammatory properties relying on catabolic pathways associated with oxidative phosphorylation (OXPHOS) or glycolysis. Spermidine, a natural polyamine, has been reported to regulate inflammation through inducing anti-inflammatory (M2) macrophages. However, the underlying mechanisms remain elusive. We show here that the M2-polarization induced by spermidine is mediated by mitochondrial reactive oxygen species (mtROS). The levels of mitochondrial superoxide and H₂O₂ were markedly elevated by spermidine. Mechanistically, mtROS were found to activate AMP-activated protein kinase (AMPK), which in turn enhanced mitochondrial function. Furthermore, hypoxia-inducible factor-1α (Hif-1α) was upregulated by the AMPK activation and mtROS and was required for the expression of anti-inflammatory genes and induction of autophagy. Consistent with previous report that autophagy is required for the M2 polarization, we found that the M2 polarization induced by spermidine was also mediated by increased autophagy. The macrophages treated with spermidine in vitro were found to ameliorate Dextran Sulfate Sodium (DSS)-induced inflammatory bowel disease (IBD) in mice. Thus, spermidine can elicit an anti-inflammatory program driven by mtROS-dependent AMPK activation, Hif-1α stabilization and autophagy induction in macrophages. Our studies revealed a critical role of mtROS in shaping macrophages into M2-like phenotype and provided novel information for management of inflammatory disease by spermidine.

Antimicrobial, Antioxidant, Sensory Properties, and Emotions Induced for the Consumers of Nutraceutical Beverages Developed from Technological Functionalised Food Industry By-Products

This study aims to develop nutraceutical beverages containing food processing by-products in their formulation, and determine the opinion of consumers. This is done by testing whether they know that the main ingredients of the product are by-products, performing an overall acceptability test of the developed beverages, and evaluating the emotions induced by the newly developed beverages for consumers. The main ingredients used for the preparation of added-value beverages were fermented milk permeate (containing galactooligosaccharides), extruded and fermented wheat bran (WB) (containing ≥6.0 log₁₀ CFU g⁻¹ viable antimicrobial properties showing lactic acid bacteria (LAB) strains), and different fruit/berry by-products (FBB) (as a source of compounds showing antioxidant properties). The definition of the quantities of bioactive ingredients was based on the overall acceptability of the prepared beverages, as well as on emotions induced in consumers by the tested beverages. Functional properties of the developed beverages were proofed by the evaluation of their antimicrobial and antioxidant properties, as well as viable LAB count during storage. Desirable changes in extruded and fermented WB were obtained: Fermentation reduced sugar concentration and pH in samples with predominant lactic acid isomer L(+). In addition, the viable LAB count in the substrate was higher than 6.0 log₁₀ CFU g⁻¹, and no enterobacteria remained. By comparing the overall acceptability of the beverages enriched with WB, the highest overall acceptability was shown for the samples prepared with 10 g of the extruded and fermented WB (7.9 points). FBB showed desirable antimicrobial activity: Shepherd inhibited—2, sea buckthorn—3, blueberries—5, and raspberries—7 pathogens from the 10 tested. Comparing different beverage groups prepared with different types of FBB, in most cases (except sea buckthorn), by increasing FBB content the beverages overall acceptability was increased, and the highest score (on average, 9.5 points) was obtained for the samples prepared with 5.0 and 7.5 g of blueberries FBB. Moreover, a very strong positive correlation (r = 0.8525) was found between overall acceptability and emotion “happy” induced in consumers by the prepared beverages enriched with extruded and fermented WB and FBB. By comparing the samples prepared with the addition of WB with samples prepared with WB and FBB, it was observed that most FBB increased total phenolic compounds (TPC) content (on average, by 9.0%), except in the case of samples prepared with sea buckthorn. A very high positive correlation (r = 0.9919) was established between TPC and antioxidant activity. Finally, it can be stated that the newly developed nutraceutical beverages were acceptable for consumers, induced positive emotions, and possessed desirable antimicrobial and antioxidant properties, while being prepared in a sustainable and environmentally friendly manner.

Gut-Derived Protein-Bound Uremic Toxins

Chronic kidney disease (CKD) afflicts more than 500 million people worldwide and is one of the fastest growing global causes of mortality. When glomerular filtration rate begins to fall, uremic toxins accumulate in the serum and significantly increase the risk of death from cardiovascular disease and other causes. Several of the most harmful uremic toxins are produced by the gut microbiota. Furthermore, many such toxins are protein-bound and are therefore recalcitrant to removal by dialysis. We review the derivation and pathological mechanisms of gut-derived, protein-bound uremic toxins (PBUTs). We further outline the emerging relationship between kidney disease and gut dysbiosis, including the bacterial taxa altered, the regulation of microbial uremic toxin-producing genes, and their downstream physiological and neurological consequences. Finally, we discuss gut-targeted therapeutic strategies employed to reduce PBUTs. We conclude that targeting the gut microbiota is a promising approach for the treatment of CKD by blocking the serum accumulation of PBUTs that cannot be eliminated by dialysis.

mRNA expression of ageing-associated genes in calorie reduction is subject to donor variability and can be induced by calorie restriction mimetics

BACKGROUND

Finding ways to a healthier ageing are increasingly becoming the focus of geriatric research. One way to accomplish this could be calorie restriction, as this is known to positively influence the ageing of model organisms.

AIM

The aim of this study was to investigate the influence of calorie reduction (F. X. Mayr therapy) and of the calorie restriction mimetics resveratrol and spermidine on the expression of ageing-associated genes.

METHODS

mRNA expression in peripheral blood mononuclear cells (PBMCs) of 18 participants taking part in an F. X. Mayr therapy was analysed. The PBMCs of one additional participant were treated ex vivo with spermidine or resveratrol. mRNA expression of SIRT1, SIRT3, FOXO3 and SOD2 was determined for these two calorie restriction mimetics. For the F. X. Mayr therapy samples, mRNA of XPA was analysed additionally.

RESULTS

mRNA expression of the ageing-associated genes showed a distinct donor variation during F. X. Mayr therapy, with a significant increase in mRNA expression of SIRT1. Expression of XPA was similar to SIRT1, with a significant correlation at the last time point tested. Spermidine treatment of PBMCs resulted in a significantly increased expression of all genes tested, whereas resveratrol treatment caused a significant increase of SIRT3, FOXO3 and SOD2 mRNA expression.

CONCLUSIONS

By increasing SIRT1 and XPA mRNA expression, calorie reduction in the form of F. X. Mayr therapy could contribute to a healthier ageing; however, the donor variability observed showed that not everyone benefited from this. Calorie restriction mimetics may be an option for promote healthier ageing for those who do not benefit from calorie reduction.

The Role of the Microbiome in Food Allergy: A Review

Food allergies are common and estimated to affect 8% of children and 11% of adults in the United States. They pose a significant burden—physical, economic and social—to those affected. There is currently no available cure for food allergies. Emerging evidence suggests that the microbiome contributes to the development and manifestations of atopic disease. According to the hygiene hypothesis, children growing up with older siblings have a lower incidence of allergic disease compared with children from smaller families, due to their early exposure to microbes in the home. Research has also demonstrated that certain environmental exposures, such as a farming environment, during early life are associated with a diverse bacterial experience and reduced risk of allergic sensitization. Dysregulation in the homeostatic interaction between the host and the microbiome or gut dysbiosis appears to precede the development of food allergy, and the timing of such dysbiosis is critical. The microbiome affects food tolerance via the secretion of microbial metabolites (e.g., short chain fatty acids) and the expression of microbial cellular components. Understanding the biology of the microbiome and how it interacts with the host to maintain gut homeostasis is helpful in developing smarter therapeutic approaches. There are ongoing trials evaluating the benefits of probiotics and prebiotics, for the prevention and treatment of atopic diseases to correct the dysbiosis. However, the routine use of probiotics as an intervention for preventing allergic disease is not currently recommended. A new approach in microbial intervention is to attempt a more general modification of the gut microbiome, such as with fecal microbiota transplantation. Developing targeted bacterial therapies for food allergy may be promising for both the treatment and prevention of food allergy. Similarly, fecal microbiota transplantation is being explored as a potentially beneficial interventional approach. Overall, targeted bacterial therapies for food allergy may be promising for both the treatment and prevention of food allergy.

Regulating T-cell differentiation through the polyamine spermidine

BACKGROUND

The cross-talk between the host and its microbiota plays a key role in the promotion of health. The production of metabolites such as polyamines by intestinal-resident bacteria is part of this symbiosis shaping host immunity. The polyamines putrescine, spermine, and spermidine are abundant within the gastrointestinal tract and might substantially contribute to gut immunity.

OBJECTIVE

We aimed to characterize the polyamine spermidine as a modulator of T-cell differentiation and function.

METHODS

Naive T cells were isolated from wild-type mice or cord blood from healthy donors and submitted to polarizing cytokines, with and without spermidine treatment, to evaluate CD4⁺ T-cell differentiation in vitro. Moreover, mice were subjected to oral supplementation of spermidine, or its precursor l-arginine, to assess the frequency and total numbers of regulatory T (Treg) cells in vivo.

RESULTS

Spermidine modulates CD4⁺ T-cell differentiation in vitro, preferentially committing naive T cells to a regulatory phenotype. After spermidine treatment, activated T cells lacking the autophagy gene Atg5 fail to upregulate Foxp3 to the same extent as wild-type cells. These results indicate that spermidine's polarizing effect requires an intact autophagic machinery. Furthermore, dietary supplementation with spermidine promotes homeostatic differentiation of Treg cells within the gut and reduces pathology in a model of T-cell transfer-induced colitis.

CONCLUSION

Altogether, our results highlight the beneficial effects of spermidine, or l-arginine, on gut immunity by promoting Treg cell development.

Effect of a lifestyle intervention program with energy-restricted Mediterranean diet and exercise on the serum polyamine metabolome in individuals at high cardiovascular disease risk: a randomized clinical trial

BACKGROUND

Many food items included in the Mediterranean diet (MedDiet) are rich in polyamines, small aliphatic amines with potential cardioprotective effects. The consumption of a MedDiet could increase polyamine concentrations. Based on experimental models, polyamine concentrations may be also influenced by physical activity (PA).

OBJECTIVES

We aimed to evaluate whether an intervention based on an energy-restricted MedDiet (er-MedDiet) and PA promotion, in comparison with an energy-unrestricted MedDiet and traditional health care, influences the serum pattern of polyamines and related metabolites in subjects at high risk of cardiovascular disease (CVD).

METHODS

This was a substudy from the PREDIMED-Plus trial, an ongoing randomized clinical trial including 6874 participants allocated either to an intensive weight-loss lifestyle intervention based on er-MedDiet, PA promotion, and behavioral support (er-MedDiet + PA group), or to an energy-unrestricted MedDiet and traditional health care group (MedDiet group). A total of 75 patients (n = 38, er-MedDiet + PA group; n = 37, MedDiet group) were included in this study. Serum concentrations of arginine, ornithine, polyamines, and acetyl polyamines at baseline and 26 wk of intervention were measured by an ultra-high-performance LC-tandem MS platform.

RESULTS

At week 26, study groups had similar adherence to the MedDiet but patients randomly assigned to the er-MedDiet + PA group showed significantly lower mean energy intake (-340.3 kcal/d; 95% CI: -567.3, -113.4 kcal/d; P = 0.004), higher mean PA (1290.6; 95% CI: 39.9, 2541.3 metabolic equivalent tasks · min/d; P = 0.043), and higher mean decrease in BMI (in kg/m2) (-1.3; 95% CI: -1.8, -0.6; P < 0.001) than the MedDiet group. However, no significant differences in serum polyamines or related metabolites were found between study groups after 26 wk of intervention and no significant between-group differences were found in glycated hemoglobin, HDL-cholesterol, or triglyceride concentrations.

CONCLUSIONS

In individuals at high CVD risk, an er-MedDiet with increased PA did not result in significant changes of serum concentrations of polyamines or related metabolites in comparison with an energy-unrestricted MedDiet and no increase in PA. This trial was registered at isrctn.com as ISRCTN89898870.

Dairy Intake in 2 American Adult Cohorts Associates with Novel and Known Targeted and Nontargeted Circulating Metabolites

BACKGROUND

The role of dairy in health can be elucidated by investigating circulating metabolites associated with intake.

OBJECTIVES

We sought to identify metabolites associated with quantity and type of dairy intake in the Framingham Heart Study Offspring and Third Generation (Gen3) cohorts.

METHODS

Dairy intake (total dairy, milk, cheese, yogurt, and cream/butter) was analyzed in relation to targeted (Offspring, n = 2205, 55.1 ± 9.8 y, 52% female, 217 signals; Gen3, n = 866, 40.5 ± 8.8 y, 54.9% female, 79 signals) and nontargeted metabolites (Gen3, ∼7031 signals) in a 2-step analysis including orthogonal projections to latent structures with discriminant analysis (OPLS-DA) in discovery subsets to identify metabolites distinguishing between high and low intake; and linear regression in confirmation subsets to assess putative associations, subsequently tested in the total samples. Previously reported associations were also investigated.

RESULTS

OPLS-DA in the Offspring targeted discovery subset resulted in a variable importance in projection (VIP) >1 of 65, 60, 58, 66, and 60 metabolites for total dairy, milk, cream/butter, cheese, and yogurt, respectively, of which 5, 3, 1, 6, and 4 metabolites, respectively, remained after confirmation. In the Gen3 targeted discovery subset, OPLS-DA resulted in a VIP >1 of 17, 15, 13, 7, and 6 metabolites for total dairy, milk, cream/butter, cheese, and yogurt, respectively. In the Gen3 nontargeted discovery subset, OPLS-DA resulted in a VIP >2 of 203, 503, 78, 186, and 206 metabolites, respectively. Combining targeted and nontargeted results in Gen3, significant associations of 7 (6 unannotated), 2, 12 (11 unannotated), 0, and 61 (all unannotated) metabolites, respectively, remained. Candidate identities of unannotated signals included fatty acids and food flavorings. Results supported relations previously reported for C14:0 sphingomyelin, and marginal associations for deoxycholates.

CONCLUSIONS

Dairy in 2 American adult cohorts associated with numerous circulating metabolites. Reports about diet-metabolite relations and confirmation of previous findings might be limited by specificity of dietary intake and breadth of measured metabolites.

Accumulation of Agmatine, Spermidine, and Spermine in Sprouts and Microgreens of Alfalfa, Fenugreek, Lentil, and Daikon Radish

Sprouts and microgreens are a rich source of various bioactive compounds. Seeds of lentil, fenugreek, alfalfa, and daikon radish seeds were germinated and the contents of the polyamines agmatine (AGM), putrescine (PUT), cadaverine (CAD), spermidine (SPD), and spermine (SPM) in ungerminated seeds, sprouts, and microgreens were determined. In general, sprouting led to the accumulation of the total polyamine content. The highest levels of AGM (5392 mg/kg) were found in alfalfa microgreens, PUT (1079 mg/kg) and CAD (3563 mg/kg) in fenugreek sprouts, SPD (579 mg/kg) in lentil microgreens, and SPM (922 mg/kg) in fenugreek microgreens. A large increase in CAD content was observed in all three legume sprouts. Conversely, the nutritionally beneficial polyamines AGM, SPD, and SPM were accumulated in microgreens, while their contents of CAD were significantly lower. In contrast, daikon radish sprouts exhibited a nutritionally better profile of polyamines than the microgreens. Freezing and thawing of legume sprouts resulted in significant degradation of CAD, PUT, and AGM by endogenous diamine oxidases. The enzymatic potential of fenugreek sprouts can be used to degrade exogenous PUT, CAD, and tyramine at pH values above 5.

Biogenic Amines in Alcohol-Free Beverages

Biogenic amines are ubiquitous bioactive compounds that are synthesized by living organisms and perform essential functions for their metabolism. In the human diet, their excessive intake can cause food poisoning. In food, especially in alcohol-free beverages, biogenic amines can be synthesized by enzymes, naturally present in raw materials, or by microorganisms, which may be naturally present in the matrix or be added during beverage transformation processes. For this reason, in alcohol-free beverages, biogenic amine amount can be considered, above a certain level, as undesired microorganism activity. Therefore, it is important to evaluate the biogenic amine profile of non-alcoholic beverages in order to monitor food quality and safety. Moreover, biogenic amines can be taken into account by industries in order to monitor production processes and products. This review article provides an overview on the biogenic amine profile of alcohol-free beverages (plant milk, nervine drinks, soft drinks, and fruit juices). Furthermore, the clinical and toxicological effects, the biogenic amines legislation, and biogenic amine synthesis have been evaluated in non-alcoholic beverages.

Identification of a Spermidine Synthase Gene from Soybean by Recombinant Expression, Transcriptional Verification, and Sequence Analysis

Spermidine possesses multiple healthy functions, and soybeans contain the most abundant spermidine. In this study, spermidine contents of soybeans from different varieties and production regions in China were evaluated, and a spermidine synthase gene (speE) was identified by recombinant expression, transcriptional verification, and sequence analysis. Spermidine contents of soybean samples from 18 varieties ranged 72.38-228.82 mg/kg, and those from 19 production regions ranged 134.64-242.32 mg/kg. The highest-spermidine sample GZ was used to clone four predicted speE genes. Expressing the gene speE5 improved the spermidine titer by 54% in Bacillus amyloliquefaciens, confirming that speE5 was involved in spermidine synthesis. Transcriptional verification was performed through a soybean germination model. Germination for 48 h led to a onefold increase of spermidine in samples SHX and HB, and corresponding speE5 transcriptional levels were improved by 26-fold and 18-fold, respectively, further verifying the function of speE5. Finally, the sequences of the speE5 gene and deduced amino acids were analyzed, and the conserved sites and catalysis mechanisms were presented. This study identified an active spermidine synthase gene from soybean for the first time, which provided an important gene resource for genetic breeding of spermidine-rich soybean or microbial cell factory.

The Polyamine Spermidine Modulates the Production of the Bacterial Genotoxin Colibactin

Colibactin-producing Escherichia coli strains are associated with cancerous and precancerous colorectal tissues and are suspected of promoting colorectal carcinogenesis. In this study, we describe a new interplay between the synthesis of the genotoxin colibactin and the polyamine spermidine. Polyamines are highly abundant in cancer tissue and are associated with cell proliferation. The need for spermidine in genotoxic activity provides a new perspective on the role of these metabolites in the pathogenicity of colibactin-producing E. coli strains in colorectal cancer.

Colibactin is a polyketide/nonribosomal peptide produced by Escherichia coli strains that harbor the pks island. This toxin induces DNA double-strand breaks and DNA interstrand cross-links in infected eukaryotic cells. Colibactin-producing strains are found associated with colorectal cancer biopsy specimens and promote intestinal tumor progression in various murine models. Polyamines are small polycationic molecules produced by both microorganisms and eukaryotic cells. Their levels are increased in malignancies, where they contribute to disease progression and metastasis. In this study, we demonstrated that the endogenous spermidine synthase SpeE is required for full genotoxic activity of colibactin-producing E. coli. Supplying spermidine in a ΔspeE pks⁺E. coli strain restored genotoxic activity. Spermidine is involved in the autotoxicity linked to colibactin and is required for direct damaging activity on DNA. The production of the colibactin prodrug motif is impaired in ΔspeE mutants. Therefore, we demonstrated that spermidine has a direct impact on colibactin synthesis.

IMPORTANCE Colibactin-producing Escherichia coli strains are associated with cancerous and precancerous colorectal tissues and are suspected of promoting colorectal carcinogenesis. In this study, we describe a new interplay between the synthesis of the genotoxin colibactin and the polyamine spermidine. Polyamines are highly abundant in cancer tissue and are associated with cell proliferation. The need for spermidine in genotoxic activity provides a new perspective on the role of these metabolites in the pathogenicity of colibactin-producing E. coli strains in colorectal cancer.

Spermidine-enhanced autophagic flux improves cardiac dysfunction following myocardial infarction by targeting the AMPK/mTOR signalling pathway

BACKGROUND AND PURPOSE

Spermidine, a natural polyamine, is abundant in mammalian cells and is involved in cell growth, proliferation, and regeneration. Recently, oral spermidine supplements were cardioprotective in age-related cardiac dysfunction, through enhancing autophagic flux. However, the effect of spermidine on myocardial injury and cardiac dysfunction following myocardial infarction (MI) remains unknown.

EXPERIMENTAL APPROACH

We determined the effects of spermidine in a model of MI, Sprague-Dawley rats with permanent ligation of the left anterior descending artery, and in cultured neonatal rat cardiomyocytes (NRCs) exposed to angiotensin II (Ang II). Cardiac function in vivo was assessed with echocardiography. In vivo and in vitro studies used histological and immunohistochemical techniques, along with western blots.

KEY RESULTS

Spermidine improved cardiomyocyte viability and decreased cell necrosis in NRCs treated with angiotensin II. In rats post-MI, spermidine reduced infarct size, improved cardiac function, and attenuated myocardial hypertrophy. Spermidine also suppressed the oxidative damage and inflammatory cytokines induced by MI. Moreover, spermidine enhanced autophagic flux and decreased apoptosis both in vitro and in vivo. The protective effects of spermidine on cardiomyocyte apoptosis and cardiac dysfunction were abolished by the autophagy inhibitor chloroquine, indicating that spermidine exerted cardioprotective effects at least partly through promoting autophagic flux, by activating the AMPK/mTOR signalling pathway.

CONCLUSIONS AND IMPLICATIONS

Our findings suggest that spermidine improved MI-induced cardiac dysfunction by promoting AMPK/mTOR-mediated autophagic flux.

Polyamines in Food

The polyamines spermine, spermidine, and putrescine are involved in various biological processes, notably in cell proliferation and differentiation, and also have antioxidant properties. Dietary polyamines have important implications in human health, mainly in the intestinal maturation and in the differentiation and development of immune system. The antioxidant and anti-inflammatory effect of polyamine can also play an important role in the prevention of chronic diseases such as cardiovascular diseases. In addition to endogenous synthesis, food is an important source of polyamines. Although there are no recommendations for polyamine daily intake, it is known that in stages of rapid cell growth (i.e., in the neonatal period), polyamine requirements are high. Additionally, de novo synthesis of polyamines tends to decrease with age, which is why their dietary sources acquire a greater importance in an aging population. Polyamine daily intake differs among to the available estimations, probably due to different dietary patterns and methodologies of data collection. Polyamines can be found in all types of foods in a wide range of concentrations. Spermidine and spermine are naturally present in food whereas putrescine could also have a microbial origin. The main polyamine in plant-based products is spermidine, whereas spermine content is generally higher in animal-derived foods. This article reviews the main implications of polyamines for human health, as well as their content in food and breast milk and infant formula. In addition, the estimated levels of polyamines intake in different populations are provided.

Spermidine Confers Liver Protection by Enhancing NRF2 Signaling Through a MAP1S-Mediated Noncanonical Mechanism

Spermidine (SPD), a naturally occurring polyamine, has been recognized as a caloric restriction mimetic that confers health benefits, presumably by inducing autophagy. Recent studies have reported that oral administration of SPD protects against liver fibrosis and hepatocarcinogenesis through activation of microtubule associated protein 1S (MAP1S)-mediated autophagy. Nuclear factor (erythroid-derived 2)-like 2 (NRF2) is a transcription factor that mediates cellular protection by maintaining the cell's redox, metabolic, and proteostatic balance. In this study, we demonstrate that SPD is a noncanonical NRF2 inducer, and that MAP1S is a component of this noncanonical pathway of NRF2 activation. Mechanistically, MAP1S induces NRF2 signaling through two parallel mechanisms, both resulting in NRF2 stabilization: (1) MAP1S competes with Kelch-like ECH-associated protein 1 (KEAP1) for NRF2 binding through an ETGE motif, and (2) MAP1S accelerates p62-dependent degradation of KEAP1 by the autophagy pathway. We further demonstrate that SPD confers liver protection by enhancing NRF2 signaling. The importance of both NRF2 and p62-dependent autophagy in SPD-mediated liver protection was confirmed using a carbon tetrachloride-induced liver fibrosis model in wild-type, Nrf2-/- , p62-/- and Nrf2-/- ;p62-/- mice, as the protective effect of SPD was significantly reduced in NRF2 or p62 single knockout mice, and completely abolished in the double knockout mice. Conclusion: Our results demonstrate the pivotal role of NRF2 in mediating the health benefit of SPD, particularly in the context of liver pathologies.

Nutrients’ and Antinutrients’ Seed Content in Common Bean (Phaseolus vulgaris L.) Lines Carrying Mutations Affecting Seed Composition

Lectins, phytic acid and condensed tannins exert major antinutritional effects in common bean when grains are consumed as a staple food. In addition, phaseolin, i.e., the major storage protein of the bean seed, is marginally digested when introduced in the raw form. Our breeding target was to adjust the nutrient/antinutrient balance of the bean seed for obtaining a plant food with improved nutritional value for human consumption. In this study, the seeds of twelve phytohaemagglutinin-E-free bean lines carrying the mutations low phytic acid, phytohaemagglutinin-L-free, α-Amylase inhibitors-free, phaseolin-free, and reduced amount of condensed tannins, introgressed and differently combined in seven genetic groups, were analyzed for their nutrient composition. Inedited characteristics, such as a strong positive correlation (+0.839**) between the genetic combination “Absence of phaseolin + Presence of the α-Amylase Inhibitors” and the amount of “accumulated iron and zinc”, were detected. Three lines carrying this genetic combination showed a much higher iron content than the baseline (+22.4%) and one of them in particular, achieved high level (+29.1%; 91.37 µg g−1) without any specific breeding intervention. If confirmed by scientific verification, the association of these genetic traits might be usefully exploited for raising iron and zinc seed content in a bean biofortification breeding program.

Changes in Polyamine Content in Rice Bran due to Fermentation with Aspergillus oryzae Analyzed by LC/ESI-MS/MS Combined with Derivatization

Many studies have demonstrated that the dietary supplementation of polyamines, especially spermidine (SPD), prevents age-related diseases. Rice bran is rich in polyamines and their amounts could be increased by fermentation with Aspergillus oryzae (A. oryzae). In this study, we developed a method for the determination of putrescine (PUT), SPD and spermine (SPM) in rice bran samples by liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) after derivatization with 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F). The derivatization improved the LC retention and ESI-MS/MS detectability of the polyamines, and consequently enabled precise and accurate quantification. Using this method, we found that the SPD content increased to 158% due to fermentation with A. oryzae, while the content of PUT and SPM decreased. SPD is known as the polyamine playing a central role in cell proliferation and growth, and therefore has health benefits. The fermented rice bran might be a good material for functional foods aimed at SPD supplementation.

A novel comprehensive paradigm for the etiopathogenesis of multiple sclerosis: therapeutic approaches and future perspectives on its treatment

It is well recognized that variation in the geographical distribution of prevalence of multiple sclerosis (MS) exists: increasing the latitude its prevalence increases as well, but the underlying causes of such dissimilarity still remained elusive as of today. Currently, the most accredited hypothesis is that the closer to the equator the more pronounced is the amount of sunlight which, in turn, increases the production of vitamin D. Cholecalciferol is indeed deficient in MS patients, but this factor does not explain by itself the etiopathogenesis of the disease. In the present study, to search for a pattern and provide a model of the disease's etiology consistent with this regional factor, as well with its changing ethnic, sex-ratio, lifestyle variations and the other unexplained aspects of MS, an extensive analysis of peer-reviewed literature and data was conducted. The arisen hypothesis was that, increasing the latitude, the factor that varies and can have the stronger effect on the human organism, is the continuous and ever-increasing diversity of the natural light-dark cycle. The consequent effort of the suprachiasmatic nucleus to entrain the organism's circadian rhythm affects the hypothalamic-pituitary-adrenal axis resulting in desynchronizing the central and peripheral circadian clocks and pathologizing the immunitary system. To verify such hypothesis, a theoretical framework of the etiopathogenesis, coherent with the gathered literature, was conceived and a demonstration to corroborate it was eventually devised and performed. The results underscored that people living in countries subjected to a further circadian disruptive factor, as daylight saving time, have a 6.35 times higher prevalence of MS than States placed on their same latitude that do not observe it, thus strongly supporting the hypothesis. As further reinforcement of the conclusions, it is worth mentioning that the levels of polyamines rise abruptly in autoimmune diseases. Moreover, among their numerous roles, these polycations participate to the regulation of the circadian clock so their sudden variation might disrupt it. Following these interesting findings, new perspectives in therapies are, therefore, proposed.

Dietary and Gut Microbiota Polyamines in Obesity- and Age-Related Diseases

The polyamines putrescine, spermidine, and spermine are widely distributed polycationic compounds essential for cellular functions. Intracellular polyamine pools are tightly regulated by a complex regulatory mechanism involving de novo biosynthesis, catabolism, and transport across the plasma membrane. In mammals, both the production of polyamines and their uptake from the extracellular space are controlled by a set of proteins named antizymes and antizyme inhibitors. Dysregulation of polyamine levels has been implicated in a variety of human pathologies, especially cancer. Additionally, decreases in the intracellular and circulating polyamine levels during aging have been reported. The differences in the polyamine content existing among tissues are mainly due to the endogenous polyamine metabolism. In addition, a part of the tissue polyamines has its origin in the diet or their production by the intestinal microbiome. Emerging evidence has suggested that exogenous polyamines (either orally administrated or synthetized by the gut microbiota) are able to induce longevity in mice, and that spermidine supplementation exerts cardioprotective effects in animal models. Furthermore, the administration of either spermidine or spermine has been shown to be effective for improving glucose homeostasis and insulin sensitivity and reducing adiposity and hepatic fat accumulation in diet-induced obesity mouse models. The exogenous addition of agmatine, a cationic molecule produced through arginine decarboxylation by bacteria and plants, also exerts significant effects on glucose metabolism in obese models, as well as cardioprotective effects. In this review, we will discuss some aspects of polyamine metabolism and transport, how diet can affect circulating and local polyamine levels, and how the modulation of either polyamine intake or polyamine production by gut microbiota can be used for potential therapeutic purposes.

Modulation of Autophagy for Controlling Immunity

Autophagy is an essential process that maintains physiological homeostasis by promoting the transfer of cytoplasmic constituents to autophagolysosomes for degradation. In immune cells, the autophagy pathway plays an additional role in facilitating proper immunological functions. Specifically, the autophagy pathway can participate in controlling key steps in innate and adaptive immunity. Accordingly, alterations in autophagy have been linked to inflammatory diseases and defective immune responses against pathogens. In this review, we discuss the various roles of autophagy signaling in coordinating immune responses and how these activities are connected to pathological conditions. We highlight the therapeutic potential of autophagy modulators that can impact immune responses and the mechanisms of action responsible.