Polyamines in human and animal milk

Gut metabolic changes during pregnancy reveal the importance of gastrointestinal region in sample collection

INTRODUCTION

Studies of gastrointestinal physiology and the gut microbiome often consider the influence of intestinal region on experimental endpoints. However, this same consideration is not often applied to the gut metabolome. Understanding the contribution of gut regionality may be critically important to the rapidly changing metabolic environments, such as during pregnancy.

OBJECTIVES

We sought to characterize the difference in the gut metabolome in pregnant mice stratified by region-comparing the small intestine, cecum, and feces. Pre-pregnancy feces were collected to understand the influence of pregnancy on the fecal metabolome.

METHODS

Feces were collected from CD-1 female mice before breeding. On gestation day (GD) 18, gut contents were collected from the small intestine, cecum, and descending colon. Metabolites were analyzed with LC-MS/MS using the Biocrates MetaboINDICATOR™ MxP® Quant 500 kit.

RESULTS

Of the 104 small molecule metabolites meeting analysis criteria, we found that 84 (81%) were differentially abundant based on gut region. The most significant regional comparison observed was between the cecum and small intestines, with 52 (50%) differentially abundant metabolites. Pregnancy itself altered 41 (39.4%) fecal small molecule metabolites.

CONCLUSIONS

The regional variation observed in the gut metabolome are likely due to the microbial and physiological differences between the different parts of the intestines. Additionally, pregnancy impacts the fecal metabolome, which may be due to evolving needs of both the dam and fetus.

Submerged and Solid-State Fermentation of Spirulina with Lactic Acid Bacteria Strains: Antimicrobial Properties and the Formation of Bioactive Compounds of Protein Origin

The aim of this study was to investigate the changes in bioactive compounds (L-glutamic acid (L-Glu), gamma-aminobutyric acid (GABA) and biogenic amines (BAs)) during the submerged (SMF) and solid-state (SSF) fermentation of Spirulina with lactobacilli strains (Lacticaseibacillus paracasei No. 244; Levilactobacillus brevis No. 173; Leuconostoc mesenteroides No. 225; Liquorilactobacillus uvarum No. 245). The antimicrobial properties of the untreated and fermented Spirulina against a variety of pathogenic and opportunistic strains were tested. The highest concentrations of L-Glu (3841 mg/kg) and GABA (2396 mg/kg) were found after 48 h of SSF with No. 173 and No. 244 strains, respectively. The LAB strain used for biotreatment and the process conditions, as well as the interaction of these factors, had statistically significant effects on the GABA concentration in Spirulina (p ≤ 0.001, p = 0.019 and p = 0.011, respectively). In all cases, the SSF of Spirulina had a higher total BA content than SMF. Most of the fermented Spirulina showed exceptional antimicrobial activity against Staphylococcus aureus but not against the other pathogenic bacteria. The ratios of BA/GABA and BA/L-Glu ranged from 0.5 to 62 and from 0.31 to 10.7, respectively. The GABA content was correlated with putrescine, cadaverine, histamine, tyramine, spermidine and spermine contents. The L-glutamic acid concentration showed positive moderate correlations with tryptamine, putrescine, spermidine and spermine. To summarize, while high concentrations of desirable compounds are formed during fermentation, the formation of non-desirable compounds (BAs) must also be considered due to the similar mechanism of their synthesis as well as the possibility of obtaining high concentrations in the end products.

Differences in Polyamine Content between Human Milk and Infant Formulas

Human milk is the gold standard for nutrition during the first months of life, but when breastfeeding is not possible, it may be replaced by infant formulas, either partially or totally. Polyamines, which play an important role in intestinal maturation and the development of the immune system, are found both in human milk and infant formulas, the first exogenous source of these compounds for the newborn. The aim of this study was to evaluate the occurrence and evolution of polyamines in human milk during the first semester of lactation and to compare the polyamine content with that of infant formulas. In total, 30 samples of human milk provided by six mothers during the first five months of lactation as well as 15 different types of infant formulas were analyzed using UHPLC-FL. Polyamines were detected in all human milk samples but with great variation among mothers. Spermidine and spermine levels tended to decrease during the lactation period, while putrescine remained practically unchanged. Considerable differences were observed in the polyamine contents and profiles between human milk and infant formulas, with concentrations being up to 30 times lower in the latter. The predominant polyamines in human milk were spermidine and spermine, and putrescine in infant formulas.

Activation of whole body by high levels of polyamine intake in rats

Polyamines are important to the survival and activation of organs and tissues via a homeostatic cell-metabolic process, and the polyamine content in cytoplasm decreases with aging. Decreases in cellular polyamine have been known to augment mutagenesis and cell death. Thus, supplementary polyamine in food is important to the prevention of aging. Here we show the anti-aging effects of oral intake of polyamine using luciferase-transgenic rats. Healthy rats, 10–12 weeks old, were given foods containing 0.01% and 0.1% (w/w) of polyamine, as compared a control food without polyamine, for 4 weeks. Using a bioimaging system, the photon intensities seen in the whole bodies and livers of rats consuming 0.1% of polyamine in food were stronger than those in rats consuming 0.01% and 0% of polyamine. However, there were no differences between groups in other characteristics, such as liver damage and body weight. In conclusion, we found that polyamine intake can activate cells throughout the whole body, providing an anti-aging effect.

Influence of Breastfeeding Factors on Polyamine Content in Human Milk

The polyamine content of human breast milk, which is the first exogenous source of polyamines for the newborn, can be affected by several factors associated with the mother, the infant, or breastfeeding itself. The aim of this study was to evaluate the influence of different breastfeeding factors on the polyamines found in human milk. For this study, a cohort of 83 mothers was considered for up to 4 months, and a subgroup of 33 mothers were followed during the first six months of breastfeeding. Two breast milk samples were collected at each sampling point (foremilk and hindmilk) and the polyamine content was determined by UHPLC-FL. Polyamine levels varied considerably between the mothers and tended to decrease over time. Putrescine was the minor polyamine, whereas spermidine and spermine contents were very similar. The concentrations of the three polyamines were significantly higher in hindmilk than foremilk (p < 0.001). Spermidine and spermine levels decreased significantly through the lactation progress (p < 0.05). Finally, slightly higher levels of polyamines were observed in the milk of mothers providing partial, rather than full, breastfeeding, although the differences were not significant. The polyamine content in human milk was found to change during a single feed (foremilk versus hindmilk) and as lactation progressed, mainly in response to the specific circumstances of the newborn.

Breast Milk: A Source of Functional Compounds with Potential Application in Nutrition and Therapy

Breast milk is an unbeatable food that covers all the nutritional requirements of an infant in its different stages of growth up to six months after birth. In addition, breastfeeding benefits both maternal and child health. Increasing knowledge has been acquired regarding the composition of breast milk. Epidemiological studies and epigenetics allow us to understand the possible lifelong effects of breastfeeding. In this review we have compiled some of the components with clear functional activity that are present in human milk and the processes through which they promote infant development and maturation as well as modulate immunity. Milk fat globule membrane, proteins, oligosaccharides, growth factors, milk exosomes, or microorganisms are functional components to use in infant formulas, any other food products, nutritional supplements, nutraceuticals, or even for the development of new clinical therapies. The clinical evaluation of these compounds and their commercial exploitation are limited by the difficulty of isolating and producing them on an adequate scale. In this work we focus on the compounds produced using milk components from other species such as bovine, transgenic cattle capable of expressing components of human breast milk or microbial culture engineering.

The Impact of Plant-Based Non-Dairy Alternative Milk on the Dairy Industry

Vegetarians have claimed and actively promoted the advantages of plant-based alternative milks as the best option for human nutrition and health, compared to the natural dairy milk. However, numerous scientific evidences and reports have demonstrated that the natural milk possesses more beneficial nutrients and bioactive components than artificially manufactured plant-derived milks. The biochemical and nutritional advantages and functionalities of natural dairy milk cannot be replaced by man-made or crafted plant-based beverage products. On the other hand, the tremendous increase in production and consumption of the plant-based alternative milks in recent years has led a serious business downturn in traditional roles and stability of the dairy industry, especially in the major dairy producing Western countries. Although plant-based milk alternatives may have some benefits on nutrition and health of certain consumers, the plant-derived alternative milks may not overshadow the true values of natural milk. Milk is not a high fat and high cholesterol food as animal meat products. Unlike plant-based alternative milks, natural milk contains many bioactive as well as antiappetizing peptides, which can reduce body weight. It has proven that taking low-fat, cultured and lactase treated milk and dairy products with other diversified nutritionally balanced diets have been shown to be healthier dietary option than plant-based milk/foods alone.

Nutritional Aspects of Spermidine

Natural polyamines (spermidine and spermine) are small, positively charged molecules that are ubiquitously found within organisms and cells. They exert numerous (intra)cellular functions and have been implicated to protect against several age-related diseases. Although polyamine levels decline in a complex age-dependent, tissue-, and cell type–specific manner, they are maintained in healthy nonagenarians and centenarians. Increased polyamine levels, including through enhanced dietary intake, have been consistently linked to improved health and reduced overall mortality. In preclinical models, dietary supplementation with spermidine prolongs life span and health span. In this review, we highlight salient aspects of nutritional polyamine intake and summarize the current knowledge of organismal and cellular uptake and distribution of dietary (and gastrointestinal) polyamines and their impact on human health. We further summarize clinical and epidemiological studies of dietary polyamines.

Poly(3-hydroxybutyrate)/poly(amine)-coated nickel oxide nanoparticles for norfloxacin delivery: antibacterial and cytotoxicity efficiency

Sustained release dosage forms enable prolonged and continuous release of a drug in the gastrointestinal tract for medication characterized by a short half lifetime. In this study, the effect of blending polyamine on poly(3-hydroxybutyrate) (PHB) as a carrier for norfloxacin (NF) was studied. The prepared blend was mixed with different amounts of NiO nanoparticles and characterized using FTIR analysis, X-ray diffraction analysis, thermogravimetric analysis, dynamic light scattering, transmission electron microscopy and scanning electron microscopy. It was found that the drug released from the nanocomposite has a slow rate in comparison with NiO, PHB, and PHB/polyamine blend. The highest ratio of NiO content to the matrix (highest NF loading), leads to a slower rate of drug release. The release from the nanocomposites showed a faster rate at pH = 2 than that at pH = 7.4. The mechanisms of NF adsorption and release were studied on PHB/polyamine-3% NiO nanocomposite. In addition, the antimicrobial efficacy of nanocomposites loaded with the drug was determined and compared with the free drug. Inclusion of NiO into PHB/polyamine showed a higher efficacy against Streptococcus pyogenes and Pseudomonas aeruginosa than the free NF. Moreover, the cytotoxicity of PHB/polyamine-3% NiO against HePG-2 cells was investigated and compared with PHB and PHB/polyamine loaded with the drug. The most efficient IC50 was found for NF@PHB/polyamine-3% NiO (29.67 μg mL-1). No effect on cell proliferation against the normal human cell line (WISH) was observed and IC50 was detected to be 44.95 and 70 μg mL-1 for NiO nanoparticles and the PHB/polyamine-3% NiO nanocomposite, respectively indicating a selectivity of action towards tumor cells coupled with a lack of cytotoxicity towards normal cells.

A sensitive and high-throughput fluorescent method for determination of oxidase activities in human, bovine, goat and camel milk

Milk oxidases are an integral part of milk immune system, and good indicators for milk thermal history. Current assay methods for milk oxidases are either insensitive, tedious or not cost-effective. In this study, a high-throughput fluorescence assay method for determination of xanthine oxidase (XO) and polyamine oxidase (PAO) activities in milk samples was developed. The hydrogen peroxide generated by XO catalysed oxidation of hypoxanthine, and PAO catalysed oxidation of spermine, was coupled to horseradish peroxidase conversion of Amplex® Red (1-(3,7-dihydroxyphenoxazin-10-yl)ethanone) to the fluorescent product resorufin. The assay was highly sensitive, with limits of detection of activity in milk being 3 × 10^-7 and 7 × 10^-7 U/mL for XO and PAO, respectively. Intra-run and inter-run results showed good assay repeatability and reproducibility. The assay was successfully applied to survey the XO and PAO activities in human, bovine, goat and camel milk samples, and it can be readily adapted for measurements of other oxidase activities.

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.

Biogenic amines profile and concentration in commercial milks for infants and young children

Commercial milks for infants and young children (CMIYC) received much attention during last years for their impact on the nutritional status, health and development of the new-born and babies. Among possible contaminants contained in these foods, biogenic amines (BAs) have rarely been determined although they can exert toxic effects in humans if ingested at high concentrations. Spermine, spermidine, putrescine, histamine, tyramine, β-phenylethylamine and cadaverine have been quantified in CMIYC samples by LC-UV after derivatisation with dansyl-chloride. Once optimised in terms of linearity (R² ≥ 0.989), recovery percentages (92.9-97.3), LOD (0.2-0.4 μg g^-1 or 0.03-0.05 μg mL^-1 depending on the samples), LOQ (0.5-1.0 μg g^-1 and 0.08-0.13 μg mL^-1 depending on the samples) and repeatability (0.1-0.2 intra-day; 0.2-0.4 inter-day), the method has been applied to real samples. Very low total BAs concentrations have been found in reconstituted (1.18-3.12 mg L^-1) and liquid milks (0.33-2.30 mg L^-1), with different biogenic amine profiles and distributions. A risk assessment based on the available information regarding Acute Reference Doses of histamine and tyramine, as well as the application of common Biogenic Amine Indexes, showed that none of the analysed samples represented a possible risk for babies, also considering a worst case evaluation. These findings confirmed the strict safety and quality protocols adopted during the production of CMIYC. Chemical compounds studied in this article: Ammonium chloride (PubChem CID: 25517); Cadaverine hydrochloride (PubChem CID: 5351467); Hydrochloridric acid (PubChem CID: 313); Histamine dihydrochloride (PubChem CID: 5818); Phenylethylamine hydrochloride (PubChem CID: 9075); Putrescine dihydrochloride (PubChem CID: 9532); Sodium hydroxide (PubChem CID: 14798); Spermine tetrahydrochloride (PubChem CID: 1103); Spermidine trihydrochloride (PubChem CID: 1102); Tyramine hydrochloride (PubChem CID: 66449).

Chemistry of Human Breast Milk-A Comprehensive Review of the Composition and Role of Milk Metabolites in Child Development

Early nutrition has an enormous influence on a child's physiological function, immune system maturation, and cognitive development. Human breast milk (HBM) is recognized as the gold standard for human infant nutrition. According to a WHO report, breastfeeding is considered as an unequaled way of providing ideal food to the infant, which is required for his healthy growth and development. HBM contains various macronutrients (carbohydrates, proteins, lipids, and vitamins) as well as numerous bioactive compounds and interactive elements (growth factors, hormones, cytokines, chemokines, and antimicrobial compounds. The aim of this review is to summarize and discuss the current knowledge about metabolites, which are the least understood components of HBM, and their potential role in infant development. We focus on small metabolites (<1500 Da) and characterize the chemical structure and biological function of polar metabolites such as human milk oligosaccharides, nonprotein molecules containing nitrogen (creatine, amino acids, nucleotides, polyamines), and nonpolar lipids. We believe that this manuscript will provide a comprehensive insight into a HBM metabolite composition, chemical structure, and their role in a child's early life nutrition.

Development of Tyrosine Decarboxylase-Negative Strains of Lactobacillus curvatus by Classical Strain Improvement

Biogenic amines have been widely studied because of their potential toxicity in fermented foods. Several lactic acid bacteria have the potential to decarboxylate the amino acid tyrosine to tyramine. In this work, we identified two strains of Lactobacillus curvatus, Lbc1 and Lbc2, endowed with the ability to produce tyramine, a metabolic feature that limits their application in starter cultures for fermented meat. To overcome this limitation, we set out to eliminate tyramine production from L. curvatus strains by using classical strain improvement. About 4,000 mutant isolates of both strains were screened using a colorimetric method, and then potential tyrosine decarboxylase-negative mutants were selected. Firm identification of loss-of-function mutants was performed by analytical determination of tyrosine and tyramine in cultivation medium. Of the 8,000 mutants screened, only one mutant of Lbc1 and two mutants of Lbc2 had completely lost the potential to produce tyramine. Subsequently, one tyrosine decarboxylase-negative mutant of both Lbc1 and Lbc2 was characterized in more detail. DNA sequencing of the Lbc1 mutant tdcA gene disclosed two missense mutations in the promoter distal part of the coding sequence. These two mutations result in two amino acid changes in the encoded tyrosine decarboxylase, Pro87Thr and Ser130Leu, presumably inactivating the enzyme activity. The DNA sequence of the other characterized mutant, derived from strain Lbc2, showed that insertion of a 6-bp fragment at nucleotide position 1348 in the tdc gene is presumably the factor leading to loss of activity. With the successful elimination of the undesirable tyramine-producing phenotype without the use of recombinant DNA technology, these developed L. curvatus mutant strains can be safely used in the dairy industry or in the manufacture of various food products.

Spermidine Protects against Oxidative Stress in Inflammation Models Using Macrophages and Zebrafish

Spermidine is a naturally occurring polyamine compound that has recently emerged with anti-aging properties and suppresses inflammation and oxidation. However, its mechanisms of action on anti-inflammatory and antioxidant effects have not been fully elucidated. In this study, the potential of spermidine for reducing pro-inflammatory and oxidative effects in lipopolysaccharide (LPS)-stimulated macrophages and zebrafish was explored. Our data indicate that spermidine significantly inhibited the production of pro-inflammatory mediators such as nitric oxide (NO) and prostaglandin E₂ (PGE₂), and cytokines including tumor necrosis factor-α and interleukin-1β in RAW 264.7 macrophages without any significant cytotoxicity. The protective effects of spermidine accompanied by a marked suppression in their regulatory gene expression at the transcription levels. Spermidine also attenuated the nuclear translocation of NF-κB p65 subunit and reduced LPS-induced intracellular accumulation of reactive oxygen species (ROS) in RAW 264.7 macrophages. Moreover, spermidine prevented the LPS-induced NO production and ROS accumulation in zebrafish larvae and was found to be associated with a diminished recruitment of neutrophils and macrophages. Although more work is needed to fully understand the critical role of spermidine on the inhibition of inflammation-associated migration of immune cells, our findings clearly demonstrate that spermidine may be a potential therapeutic intervention for the treatment of inflammatory and oxidative disorders.

Plasticizing Effects of Polyamines in Protein-Based Films

Zeta potential and nanoparticle size were determined on film forming solutions of native and heat-denatured proteins of bitter vetch as a function of pH and of different concentrations of the polyamines spermidine and spermine, both in the absence and presence of the plasticizer glycerol. Our results showed that both polyamines decreased the negative zeta potential of all samples under pH 8.0 as a consequence of their ionic interaction with proteins. At the same time, they enhanced the dimension of nanoparticles under pH 8.0 as a result of macromolecular aggregations. By using native protein solutions, handleable films were obtained only from samples containing either a minimum of 33 mM glycerol or 4 mM spermidine, or both compounds together at lower glycerol concentrations. However, 2 mM spermidine was sufficient to obtain handleable film by using heat-treated samples without glycerol. Conversely, brittle materials were obtained by spermine alone, thus indicating that only spermidine was able to act as an ionic plasticizer. Lastly, both polyamines, mainly spermine, were found able to act as “glycerol-like” plasticizers at concentrations higher than 5 mM under experimental conditions at which their amino groups are undissociated. Our findings open new perspectives in obtaining protein-based films by using aliphatic polycations as components.

Biogenic amines in Zamorano cheese: factors involved in their accumulation

BACKGROUND

Ripened cheese is among fermented food the most often associated with food poisoning from biogenic amines. The influence of ripening time, heat treatment of milk and the effect of using milk from a different ewe breed on the biogenic amine (BA) content of Zamorano cheese was studied by high-performance liquid chromatography. Physicochemical, proteolytic and microbiological parameters were also studied.

RESULTS

BA content increased significantly during ripening and their final values were around 400 mg kg(-1). Cheeses elaborated with raw milk duplicated the concentration of BA relative to those elaborated with pasteurized milk (72 °C for 20 s). The average levels of putrescine, spermine and tyramine were higher in cheeses made with a greater proportion of milk from Churra breed. Significant differences in microbial counts and nitrogen soluble in 5% phosphotungstic acid were observed between the different batches.

CONCLUSION

Ripening time and heat treatment applied to milk were the factors that exercised the greatest influence upon the concentration of BA in Zamorano cheese.

The effects of polyamines on human colonic mucosal function

Electrogenic ion transport in human colon is a surrogate marker for colonic mucosal function, and may be manipulated by a variety of hormonal, neural, immune and paracrine mediators. Polyamines are present in vast quantities in the colonic lumen and appear to be integral to cellular function. This study explores some of the mechanisms of polyamine action on colonic tissue through study of their effects on differential secretory pathways, as well as examining their actions on intracellular cAMP and Ca(2+) accumulation. Human colonic mucosa was mounted in Ussing chambers and treated with polyamines (spermine, spermidine and putrescine) with changes in ion transport recorded. In separate experiments colonic crypts were treated with polyamines and intracellular cAMP levels determined by ELISA and intracellular calcium concentrations were quantified by fluorescent imaging. Polyamines at physiological concentrations (1mM) exert no effects on basal mucosal chloride secretion or transepithelial electrical resistance. Polyamines inhibit electrogenic ion secretion as stimulated by forskolin (cAMP-mediated), but not carbachol (Ach-mediated). All the polyamines used in this study inhibited intracellular cAMP accumulation, according to potency (spermine>spermidine>putrescine). Spermine increased intracellular Ca(2+) in a PKC-dependent manner, likely due to its effects on the extracellular calcium-sensing receptor (CaSR). Polyamines act to prevent cAMP-mediated Cl(-) hypersecretion in the colon, acting through CaSR to inhibit PKC-mediated [Ca(2+)]i release from intracellular stores.

Resembling breast milk: influence of polyamine-supplemented formula on neonatal BALB/cOlaHsd mouse microbiota

Infant microbiota is influenced by numerous factors, such as delivery mode, environment, prematurity and diet (breast milk or formula). In addition to its nutritional value, breast milk contains bioactive substances that drive microbial colonisation and support immune system development, which are usually not present in infant formulas. Among these substances, polyamines have been described to be essential for intestinal and immune functions in newborns. However, their effect on the establishment of microbiota remains unclear. Therefore, the aim of the present study was to ascertain whether an infant formula supplemented with polyamines has an impact on microbial colonisation by modifying it to resemble that in breast-fed neonatal BALB/c mice. In a 4 d intervention, a total of sixty pups (14 d old) were randomly assigned to the following groups: (1) breast-fed group; (2) non-enriched infant formula-fed group; (3) three different groups fed an infant formula enriched with increasing concentrations of polyamines (mixture of putrescine, spermidine and spermine), following the proportions found in human milk. Microbial composition in the contents of the oral cavity, stomach and small and large intestines was analysed by quantitative PCR targeted at fourteen bacterial genera and species. Significantly different (P< 0·05) microbial colonisation patterns were observed in the entire gastrointestinal tract of the breast-fed and formula-fed mice. In addition, our findings demonstrate that supplementation of polyamines regulates the amounts of total bacteria,Akkermansia muciniphila,Lactobacillus,Bifidobacterium,Bacteroides–PrevotellaandClostridiumgroups to levels found in the breast-fed group. Such an effect requires further investigation in human infants, as supplementation of an infant formula with polyamines might contribute to healthy gastrointestinal tract development.

Polyamine levels in breast milk are associated with mothers' dietary intake and are higher in preterm than full-term human milk and formulas

BACKGROUND

Polyamine intake from milk is considered essential for post-natal maturation of the immune system and small intestine. The present study aimed to determine polyamine content in human milk after preterm delivery and the association with mothers' dietary intake. In comparison, the polyamine levels were compared with those in term breast milk and some corresponding formulas.

METHODS

Transitional breast milk was collected from 40 mothers delivering after 24-36 weeks of gestation, and from 12 mothers delivering after full term. Food intake was assessed in mothers delivering preterm babies using a 3-day diary. Polyamines were analysed by high-performance liquid chromatography.

RESULTS

The dietary intake of polyamines was significantly associated with breast milk content but weaker for spermine than for spermidine and putrescine. Total polyamine level was higher in preterm than term milk and lower in the corresponding formulas. Putrescine, spermidine and spermine contents [mean (SEM)] in preterm milk were 165.6 (25), 615.5 (80) and 167.7 (16) nmol dL⁻¹, respectively, with the levels of putrescine and spermidine being 50% and 25% higher than in term milk. The content of spermine did not differ.

CONCLUSIONS

Dietary intake of polyamines has an impact on the content in breast milk. The difference between human milk after preterm and term delivery might be considered when using donor human milk for preterm infants. The corresponding formulas had lower contents. Further studies are important for determining the relationship between tissue growth and maturation and optimal intake.

Investigating associations between milk metabolite profiles and milk traits of Holstein cows

In the field of dairy cattle research, it is of great interest to improve the detection and prevention of diseases (e.g., mastitis and ketosis) and monitor specific traits related to the state of health and management. During the standard milk performance test, traditional milk traits are monitored, and quality and quantity are screened. In addition to the standard test, it is also now possible to analyze milk metabolites in a high-throughput manner and to consider them in connection with milk traits to identify functionally important metabolites that can also serve as biomarker candidates. We present a study in which 190 milk metabolites and 14 milk traits of 1,305 Holstein cows on 18 commercial farms were investigated to characterize interrelations of milk metabolites between each other, to milk traits from the milk standard performance test, and to influencing factors such as farm and sire effect (half-sib structure). The effect of influencing factors (e.g., farm) varied among metabolites and traditional milk traits. The investigations of associations between metabolites and milk traits revealed groups of metabolites that show, for example, positive correlations to protein and casein, and negative correlations to lactose and pH. On the other hand, groups of metabolites jointly associated with the investigated milk traits can be identified and functionally discussed. To enable a multivariate investigation, 2 machine learning methods were applied to detect important metabolites that are highly correlated with the investigated traditional milk traits. For somatic cell score, uracil, lactic acid, and 9 other important metabolites were detected. Lactic acid has already been proposed as a biomarker candidate for mastitis in the recent literature. In conclusion, we found sets of metabolites eligible to predict milk traits, enabling the analysis of milk traits from a metabolic perspective and discussion of the possible functional background for some of the detected associations.

Integrating milk metabolite profile information for the prediction of traditional milk traits based on SNP information for Holstein cows

In this study the benefit of metabolome level analysis for the prediction of genetic value of three traditional milk traits was investigated. Our proposed approach consists of three steps: First, milk metabolite profiles are used to predict three traditional milk traits of 1,305 Holstein cows. Two regression methods, both enabling variable selection, are applied to identify important milk metabolites in this step. Second, the prediction of these important milk metabolite from single nucleotide polymorphisms (SNPs) enables the detection of SNPs with significant genetic effects. Finally, these SNPs are used to predict milk traits. The observed precision of predicted genetic values was compared to the results observed for the classical genotype-phenotype prediction using all SNPs or a reduced SNP subset (reduced classical approach). To enable a comparison between SNP subsets, a special invariable evaluation design was implemented. SNPs close to or within known quantitative trait loci (QTL) were determined. This enabled us to determine if detected important SNP subsets were enriched in these regions. The results show that our approach can lead to genetic value prediction, but requires less than 1% of the total amount of (40,317) SNPs., significantly more important SNPs in known QTL regions were detected using our approach compared to the reduced classical approach. Concluding, our approach allows a deeper insight into the associations between the different levels of the genotype-phenotype map (genotype-metabolome, metabolome-phenotype, genotype-phenotype).

Lower polyamine levels in breast milk of obese mothers compared to mothers with normal body weight

BACKGROUND

Obesity is associated with risks for mother and infant, and the mothers' dietary habits influence breast milk composition. Polyamines are secreted in breast milk and are essential for the regulation of intestinal and immune function in newborns and infants. The present study aimed to investigate the level of polyamines in human milk obtained from obese and normal weight mothers at different times of lactation.

METHODS

Breast milk from 50 mothers was obtained at day 3, and at 1 and 2 months after delivery. The mothers had normal body weight [body mass index (BMI) < 25 kg m(-2) ] or were obese (BMI > 30 kg/m(2) ). A subgroup of obese mothers participated in a weight reduction programme during pregnancy. Polyamines were analysed using high-performance liquid chromatography.

RESULTS

The total polyamine content was significantly lower at all times in breast milk from obese mothers compared to milk from controls. Spermine levels did not differ between groups at any time in contrast to the levels of putrescine and spermidine. Putrescine concentrations were highest on day 3 and spermidine and spermine were highest at 1 month of lactation. The obese mothers, who received dietary advice during pregnancy based on the Nordic Nutrition Recommendations, had higher concentrations of putrescine and spermidine in their milk than the obese mothers without any intervention.

CONCLUSIONS

Polyamine concentrations were lower in breast milk from obese mothers compared to mothers with a normal weight. General dietary intervention in obese mothers increased the polyamine levels, suggesting that the low levels in obesity were at least partly associated with food habits. However, the consistency of spermine suggests a special metabolic function of this polyamine.

Natural polyamine inhibits mouse skin inflammation and macrophage activation

OBJECTIVE

Natural polyamines are some of the most abundant polycationic molecules in eukaryotic cells, regulating gene expression. Polyamines have been reported to possess anti-inflammatory activities in many model inflammation systems. However, there is no report on their role in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced dermal edema.

METHODS

Mouse ear edema was induced by TPA. Edema biopsies were investigated using H&E staining. Levels of nitric oxide (NO) were determined using the Griess reaction. Tumor necrosis factor α (TNFα) and interleukin (IL)-1β levels in cell supernatants were measured by TNFα and IL-1β ELISA kits.

RESULTS

Spermidine and spermine caused significant decreases in ear thickness, water content, and neutrophil infiltrations in comparison with negative control (p < 0.05). External polyamines reduced the levels of inflammatory mediators such as NO, TNFα, and IL-1β in lipopolysaccharide (LPS)-stimulated RAW264.7 murine macrophages. Spermine had a higher inhibitory effect on the production of cytokines such as IL-1β and TNFα in LPS-stimulated murine macrophages compared to other polyamines.

CONCLUSION

Our findings clearly demonstrated that polyamines are involved in the anti-inflammatory effect by reducing dermal edema thickness and other inflammatory mediators like NO and cytokines in a dose-dependent manner.

Polyamines in human breast milk for preterm and term infants

Maternal milk is the first source of exogenous polyamines for the newborn. Polyamines modulate gut maturation in neonates, but no studies are available on polyamine concentration in human milk of preterm babies, even though they could be important for their immature gut. The present study aimed to determine polyamine concentration in human breast milk of mothers with preterm or term infants during the first month of lactation. Human milk samples were obtained during the first month of lactation from twenty-seven mothers with preterm babies and twelve mothers with babies born at term. The polyamine concentration in human milk was quantified by HPLC. During the first month of lactation, the total polyamine concentration was significantly higher in preterm milk than in term milk samples (7590 (sd 4990) v. 4660 (sd 4830) nmol/l, respectively (P =0·034)), as well as individual polyamine concentrations. Polyamine concentration in mature milk for preterm babies was significantly higher than that in mature milk for babies at term, and a similar trend was observed in colostrum and transition human milk. The spermidine/spermine ratio was higher in transition milk in preterm v. term samples, while in mature milk, the ratio was significantly lower in preterm than in term babies. In conclusion, the polyamine concentration was significantly higher in human milk for preterm than for term infants. This and the different spermidine/spermine ratios could influence the gut development of premature babies.

Impact of probiotic feeding during weaning on the serum lipid profile and plasma metabolome in infants

The gut microbiome interacts with the host in the metabolic response to diet, and early microbial aberrancies may be linked to the development of obesity and metabolic disorders later in life. Probiotics have been proposed to affect metabolic programming and blood lipid levels, although studies are lacking in infants. Here, we report on the lipid profile and global metabolic response following daily feeding of probiotics during weaning. A total of 179 healthy, term infants were randomised to daily intake of cereals with (n89) or without (n90) the addition ofLactobacillus paracaseissp.paracaseiF19 (LF19) 108colony-forming units per serving from 4 to 13 months of age. Weight, length and skinfold thickness were monitored. Venous blood was drawn at 5·5 and 13 months of age for analysis of the serum lipid profile. In a subsample, randomly selected from each group, GC-time-of-flight/MS was used to metabolically characterise plasma samples from thirty-seven infants. A combination of multi- and univariate analysis was applied to reveal differences related to LF19 treatment based on 228 putative metabolites, of which ninety-nine were identified or classified. We observed no effects of probiotic feeding on anthropometrics or the serum lipid profile. However, we detected significantly lower levels of palmitoleic acid (16 : 1) (P< 0·05) and significantly higher levels of putrescine (P< 0·01) in LF19-treated infants. Palmitoleic acid is a major MUFA strongly linked to visceral obesity, while putrescine is a polyamine with importance for gut integrity. Whether the observed differences will have long-term health consequences are being followed.

Radiation protection following nuclear power accidents: a survey of putative mechanisms involved in the radioprotective actions of taurine during and after radiation exposure

There are several animal experiments showing that high doses of ionizing radiation lead to strongly enhanced leakage of taurine from damaged cells into the extracellular fluid, followed by enhanced urinary excretion. This radiation-induced taurine depletion can itself have various harmful effects (as will also be the case when taurine depletion is due to other causes, such as alcohol abuse or cancer therapy with cytotoxic drugs), but taurine supplementation has been shown to have radioprotective effects apparently going beyond what might be expected just as a consequence of correcting the harmful consequences of taurine deficiency per se. The mechanisms accounting for the radioprotective effects of taurine are, however, very incompletely understood. In this article an attempt is made to survey various mechanisms that potentially might be involved as parts of the explanation for the overall beneficial effect of high levels of taurine that has been found in experiments with animals or isolated cells exposed to high doses of ionizing radiation. It is proposed that taurine may have radioprotective effects by a combination of several mechanisms: (1) during the exposure to ionizing radiation by functioning as an antioxidant, but perhaps more because it counteracts the prooxidant catalytic effect of iron rather than functioning as an important scavenger of harmful molecules itself, (2) after the ionizing radiation exposure by helping to reduce the intensity of the post-traumatic inflammatory response, and thus reducing the extent of tissue damage that develops because of severe inflammation rather than as a direct effect of the ionizing radiation per se, (3) by functioning as a growth factor helping to enhance the growth rate of leukocytes and leukocyte progenitor cells and perhaps also of other rapidly proliferating cell types, such as enterocyte progenitor cells, which may be important for immunological recovery and perhaps also for rapid repair of various damaged tissues, especially in the intestines, and (4) by functioning as an antifibrogenic agent. A detailed discussion is given of possible mechanisms involved both in the antioxidant effects of taurine, in its anti-inflammatory effects and in its role as a growth factor for leukocytes and nerve cells, which might be closely related to its role as an osmolyte important for cellular volume regulation because of the close connection between cell volume regulation and the regulation of protein synthesis as well as cellular protein degradation. While taurine supplementation alone would be expected to exert a therapeutic effect far better than negligible in patients that have been exposed to high doses of ionizing radiation, it may on theoretical grounds be expected that much better results may be obtained by using taurine as part of a multifactorial treatment strategy, where it may interact synergistically with several other nutrients, hormones or other drugs for optimizing antioxidant protection and minimizing harmful posttraumatic inflammatory reactions, while using other nutrients to optimize DNA and tissue repair processes, and using a combination of good diet, immunostimulatory hormones and perhaps other nontoxic immunostimulants (such as beta-glucans) for optimizing the recovery of antiviral and antibacterial immune functions. Similar multifactorial treatment strategies may presumably be helpful in several other disease situations (including severe infectious diseases and severe asthma) as well as for treatment of acute intoxications or acute injuries (both mechanical ones and severe burns) where severely enhanced oxidative and/or nitrative stress and/or too much secretion of vasodilatory neuropeptides from C-fibres are important parts of the pathogenetic mechanisms that may lead to the death of the patient. Some case histories (with discussion of some of those mechanisms that may have been responsible for the observed therapeutic outcome) are given for illustration of the likely validity of these concepts and their relevance both for treatment of severe infections and non-infectious inflammatory diseases such as asthma and rheumatoid arthritis.

Polyamines: total daily intake in adolescents compared to the intake estimated from the Swedish Nutrition Recommendations Objectified (SNO)

BACKGROUND

Dietary polyamines have been shown to give a significant contribution to the body pool of polyamines. Knowing the levels of polyamines (putrescine, spermidine, and spermine) in different foods and the contribution of daily food choice to polyamine intake is of interest, due to the association of these bioactive amines to health and disease.

OBJECTIVE

To estimate polyamine intake and food contribution to this intake in adolescents compared to a diet fulfilling the Swedish Nutrition Recommendations.

DESIGN

A cross-sectional study of dietary intake in adolescents and an 'ideal diet' (Swedish nutrition recommendations objectified [SNO]) list of foods was used to compute polyamine intake using a database of polyamine contents of foods. For polyamine intake estimation, 7-day weighed food records collected from 93 adolescents were entered into dietetic software (Dietist XP) including data on polyamine contents of foods. The content of polyamines in foods recommended according to SNO was entered in the same way.

RESULTS

The adolescents' mean daily polyamine intake was 316±170 µmol/day, while the calculated contribution according to SNO was considerably higher with an average polyamine intake of 541 µmol/day. In both adolescent's intake and SNO, fruits contributed to almost half of the total polyamine intake. The reason why the intake among the adolescents was lower than the one calculated from SNO was mainly due to the low vegetable consumption in the adolescents group.

CONCLUSIONS

The average daily total polyamine intake was similar to that previously reported in Europe. With an 'ideal' diet according to Swedish nutrition recommendations, the intake of this bioactive non-nutrient would be higher than that reported by our adolescents and also higher than that previously reported from Europe.

Polyamines in foods: development of a food database

BACKGROUND

Knowing the levels of polyamines (putrescine, spermidine, and spermine) in different foods is of interest due to the association of these bioactive nutrients to health and diseases. There is a lack of relevant information on their contents in foods.

OBJECTIVE

To develop a food polyamine database from published data by which polyamine intake and food contribution to this intake can be estimated, and to determine the levels of polyamines in Swedish dairy products.

DESIGN

Extensive literature search and laboratory analysis of selected Swedish dairy products. Polyamine contents in foods were collected using an extensive literature search of databases. Polyamines in different types of Swedish dairy products (milk with different fat percentages, yogurt, cheeses, and sour milk) were determined using high performance liquid chromatography (HPLC) equipped with a UV detector.

RESULTS

Fruits and cheese were the highest sources of putrescine, while vegetables and meat products were found to be rich in spermidine and spermine, respectively. The content of polyamines in cheese varied considerably between studies. In analyzed Swedish dairy products, matured cheese had the highest total polyamine contents with values of 52.3, 1.2, and 2.6 mg/kg for putrescine, spermidine, and spermine, respectively. Low fat milk had higher putrescine and spermidine, 1.2 and 1.0 mg/kg, respectively, than the other types of milk.

CONCLUSIONS

The database aids other researchers in their quest for information regarding polyamine intake from foods. Connecting the polyamine contents in food with the Swedish Food Database allows for estimation of polyamine contents per portion.

High performance liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometry for sensitive determination of bioactive amines in donkey milk

In the present study we report on the optimization and validation of a sensitive high performance liquid chromatography atmospheric pressure chemical ionization mass spectrometry (HPLC-APCI-MS) method for the determination of 8 bioactive amines (histamine, tyramine, tryptamine, 2-phenylethylamine, cadaverine, putrescine, spermidine and spermine) in donkey milk samples. The method involves donkey milk pre-treatment to remove proteins and pre-column dansylation of the amines. HPLC in reversed phase mode has been used for bioactive amines separation and the operating condition of the APCI-MS system proved to be powerful and very efficient for peak assignment. The separation was accomplished in a short time with an excellent resolution for all the amine peaks. Quantification was carried out by monitoring the characteristic [M+H](+) ion of each amine derivative. The method sensitivity, linearity and repeatability were assayed with satisfactory results. The detection limits of the analysed amines ranged from 0.5 microg L(-1) to 15 microg L(-1); the highest LOD was for spermine. Also remarkably good recovery values were obtained; at the lowest spiking level (1 microg L(-1)) the percent mean recoveries ranged from 77.7 to 109.7. Furthermore, as the investigations relate to a complex matrix as donkey milk, suitable studies on matrix effect were performed. Finally, the developed and validated method was applied to analyse 13 donkey milk samples. Among the identified bioactive amines, putrescine, spermine and spermidine proved to be the main amines in donkey milk. Their concentration levels in the present study were lower than the values determined in mature human, cow and sow milk.

Modulation of fecal polyamines by viewing humorous films in patients with atopic dermatitis

BACKGROUND/OBJECTIVE

Alteration of intestinal flora was involved in the pathogenesis of atopic dermatitis. Patients with atopic dermatitis were less colonized with Lactobacilli or Bifidobacterium, whereas they were more colonized with Staphylococcus aureus or Enterobacteria. Consequently, fecal levels of bacterial metabolite (polyamines) were reduced. In contrast, stress also induced intestinal mucosal dysfunction against bacteria and impaired intestinal barrier function. We studied the effect of relaxation by viewing humorous films on fecal flora and fecal levels of polyamines.

METHODS

Twenty-four healthy individuals and 24 patients with atopic dermatitis either viewed seven control nonhumorous films or seven humorous films sequentially for 7 days. Before and after viewing, feces were obtained, and fecal flora and fecal levels of polyamines were assessed.

RESULTS

Neither viewing humorous films nor viewing control nonhumorous films had any effect on healthy individuals. In contrast, viewing humorous films (i) increased colonization with lactobacilli and bifidobacterium, (ii) decreased colonization with S. aureus and Enterobacteria, and (iii) increased fecal levels of polyamines; whereas viewing control nonhumorous films failed to do so in patients with atopic dermatitis.

CONCLUSION

Viewing humorous films may modulate fecal levels of polyamines by restoring intestinal flora in atopic dermatitis.

Polyamines and the intestinal tract

Owing to their high turnover, the intestinal mucosal cells have a particularly high requirement for polyamines. Therefore, they are an excellent charcol for the study of polyamine function in rapid physiological growth and differentiation. After a cursory introduction to the major aspects of polyamine metabolism, regulation, and mode of action, we discuss the contribution of the polyamines to the maintenance of normal gut function, the maturation of the intestinal mucosa, and its repair after injuries. Repletion of cellular polyamine pools with (D,L)-2-(difluoromethyl)ornithine has considerably improved our understanding of how the polyamines are involved in the regulation of normal and neoplastic growth. Unfortunately, the attempts to exploit polyamine metabolism as a cancer therapeutic target have not yet been successful. However, the selective inactivation of ornithine decarboxylase appears to be a promising chemopreventive method in familial adenomatous polyposis. Presumably, it relies on the fact that ornithine decarboxylase is a critical regulator of the proliferative response of the protooncogene c-myc, but not of its apoptotic response.

Maternal milk contains antimicrobial factors that protect young rabbits from enteropathogenic Escherichia coli infection

Enteropathogenic Escherichia coli (EPEC) colibacillosis represents a major cause of lethal diarrhea in young children in developing countries. EPEC strains also infect numerous mammal species and represent a major economical problem in rabbit industry. Protection against this pathogen is a challenging goal both in humans and in other mammal species. Despite a good knowledge of the pathogenicity mechanisms of EPEC, the intrinsic and environmental factors that control the expression of EPEC virulence in mammals remain unknown. For instance, the exacerbated sensitivity of young mammals to EPEC infection is still unexplained. Our goal was to investigate if age or other factors, like milk consumption, could be determinants that trigger the disease. We used rabbits as an animal model to study the role of milk in the sensitivity to an EPEC infection. Weaned and suckling rabbits were orally inoculated with EPEC strain E22 (O103:H2:K-) at 28 days of age, and the evolution of the disease was investigated in the two groups. In addition, in order to better characterize the interactions between milk and EPEC, we determined in vitro bacterial growth and the abilities of EPEC cells to adhere to epithelial cells in the presence of milk. Our results demonstrate a protective role of milk in vivo in association with in vitro antibacterial activity. These effects are independent of the presence of specific anti-EPEC antibodies.

Polyamines as clinical laboratory tools

Since their discovery by Antoni van Leeuwenhoek in 1678 until the recent development of transgenic mice expressing proteins altering polyamine levels in a tissue-specific manner, polyamines have been the object of intense research efforts which have shed light on several biological and pathological processes. From the discovery of a particular form of proteasome regulation of the catabolism of the key regulatory enzyme in their synthetic pathway, to the experimental cancer treatment or prevention with polyamine antagonists or inhibitors of the latter enzyme, a whole spectrum of interests can be revealed. Still, many aspects of their functions remain elusive and difficulties inherent in their analysis, which relies on sophisticated high-performance liquid chromatographic (HPLC) methods, and the lack of standardization; have hampered the transit from the research realm to the standard clinical laboratory domain. Their assay in biological fluids has been used for cancer diagnosis and for monitoring anticancer treatment. In this article, we attempt to provide an overview of polyamine structure, nutritional value, metabolism, and physiological roles. Next, we will summarize the main analytical methods on which we count, and finally we will address their role in diagnosis of cancer as well their proposed role as antioxidant and antiglycation agents.

Immunomodulatory action of spermine and spermidine on NR8383 macrophage line in various culture conditions

We examined the effect of spermine (SPM) and spermidine (SPD) on tumor necrosis factor (TNF)alpha and monocyte chemoattractant protein-1 (MCP-1) secretion from macrophages in various culture conditions, including several protocols of polyamines addition and media supplemented with 0, 1 or 15% fetal bovine serum. TNFalpha secretion was inhibited by SPM or SPD added 18h before stimulation in a concentration-dependent manner. Their effect was directly related to the presence of FBS. When SPM or SPD was added simultaneously to the stimulus, the TNFalpha secretion inhibition was higher than that obtained after pre-treatment. In this case, the effect was inversely proportional to the presence of FBS. The addition of polyamines also inhibited the secretion of MCP-1 in NR8383 cells. We conclude that SPM and SPD inhibited the secretion of inflammatory cytokines TNFalpha and MCP-1 in different ways, depending on culture conditions. In any case, SPM was more effective than SPD.

Capillary gas chromatographic determination of spermidine in diet integrators

Biogenic polyamines, among which is spermidine (SPD, NH2-(CH2)4-NH-(CH2)3-NH2), are ubiquitous polycationic molecules that have a definitive role in many biological processes, such as nucleic acid metabolism, protein synthesis and cell growth. SPD is present in diet integrators because it seems to favour the hair growth. This work describes a capillary gas chromatographic (CGC) method for the quantitative determination of SPD in diet integrators using cadaverine internal standard (IS), a methyl siliconic capillary column and flame-ionization detector (FID). Diet tablets, containing SPD, are pulverized; an aliquot of powder is treated with an alkaline aqueous solution and added with IS. The suspension is extracted with diethyl ether containing ethyl chloroformate (ECF). The ether extracts, evaporated to dryness and reconstituted in ethyl acetate were analyzed in CGC/FID. Derivatives of polyamines with ECF were characterized in CGC/MS too. Validation has considered specificity, linearity, precision and accuracy of analytical method; this parameters are valid for the quantitative determination of SPD in diet integrators.

Immunostimulatory potential of beta-lactoglobulin preparations: effects caused by endotoxin contamination

BACKGROUND

The immunomodulating potential residing in cow's milk proteins is currently receiving increasing attention because of growing interest in functional foods and the complex problem of cow's milk allergy. One of the major cow's milk allergens, whey protein beta-lactoglobulin, has previously been shown to mediate cellular activation in both human and murine immune cells.

OBJECTIVE

We examined the response to different beta-lactoglobulin preparations in naive immune cells.

METHODS

Splenocytes and cells from mesenteric lymph nodes derived from BALB/c mice bred and maintained on a milk-free diet were cultured in vitro with different beta-lactoglobulin preparations. Cell proliferation, cytokine production, and increases in intracellular glutathione were used as cellular activation markers. Moreover, the effect of beta-lactoglobulin on cytokine production in murine bone-marrow-derived dendritic cells was examined.

RESULTS

We observed that some commercial beta-lactoglobulin preparations induced pronounced proliferation of both spleen cells and cells from mesenteric lymph nodes; production of TNF-alpha, IL-6, IL-1beta, and IL-10; and an increased level of intracellular glutathione in spleen cell cultures. Furthermore, TNF-alpha, IL-6, IL-1beta, and IL-10 production was induced in murine bone-marrow-derived dendritic cells. Purification of beta-lactoglobulin from raw milk using nondenaturating conditions, however, revealed that the beta-lactoglobulin per se did not possess the immunomodulatory activity. Eventually, the immunostimulatory effect was found to be caused by endotoxin contamination.

CONCLUSION

These results identify endotoxin as the main immunostimulatory component present in some commercial beta-lactoglobulin preparations. Moreover, the present study makes it evident that immunomodulatory effects attributed to beta-lactoglobulin need to be reassessed.

3-Aminopropanal is a lysosomotropic aldehyde that causes oxidative stress and apoptosis by rupturing lysosomes

During cerebral ischemia and following trauma, potent cytotoxic polyamine-derived aminoaldehydes form, diffuse, and damage adjacent tissues not directly subjected to the initial insult. One such aldehyde is 3-aminopropanal (3-AP). The mechanisms by which such a small aldehydic compound is excessively cytotoxic have been unclear until recently when we showed that 3-AP, having the structure of a weak lysosomotropic base, concentrates within the acidic vacuolar compartment and causes lysosomal rupture that, in turn, induces caspase activation and apoptotic cell death. Here, using cultured J774 cells and 3-AP as a way to selectively burst lysosomes, we show that moderate lysosomal rupture induces a transient wave of oxidative stress. The start of this oxidative stress period is concomitant with a short period of enhanced mitochondrial membrane potential that later fades and is replaced by a decreased potential before the oxidative stress diminishes. The result of the study suggests that oxidative stress, which has often been described during apoptosis induced by agonists other than oxidative stress per se, may be a consequence of lysosomal rupture with direct and/or indirect effects on mitochondrial respiration and electron transport causing a period of passing enhanced formation of reactive oxygen species.