Dietary spermidine and spermine participate in the maturation of galactosyltransferase activity and glycoprotein galactosylation in rat small intestine

Age-Related Mucus Barrier Dysfunction in Mice Is Related to the Changes in Muc2 Mucin in the Colon

During aging, the protective function of mucus barrier is significantly reduced among which changes in colonic mucus barrier function received the most attention. Additionally, the incidence of colon-related diseases increases significantly in adulthood, posing a threat to the health of the elderly. However, the specific changes in colonic mucus barrier with aging and the underlying mechanisms have not been fully elucidated. To understand the effects of aging on the colonic mucus barrier, changes in the colonic mucus layer were evaluated in mice aged 2, 12, 18, and 24 months. Microbial invasion, thickness, and structure of colonic mucus in mice at different months of age were analyzed by in situ hybridization fluorescence staining, AB/PAS staining, and cryo-scanning electron microscopy. Results showed that the aged colon exhibited intestinal mucus barrier dys-function and altered mucus properties. During aging, microorganisms invaded the mucus layer to reach epithelial cells. Compared with young mice, the thickness of mucus layer in aged mice in-creased by 11.66 μm. And the contents of the main components and glycosylation structure of colon changed. Among them, the proportion of goblet cells decreased significantly in older mice, and the expression of spdef genes that regulate goblet cell differentiation decreased. Further, the expression of key enzymes involved in mucin core structure formation and glycan modification also changed with aging. The expression of core 1 β1,3-galactosyltransferase (C1GalT1) which is the key enzyme forming the main core structure increased by one time, while core 2 β1,6 N-acetylglucosaminyltransferase (C2GnT) and core 3 β1,3 N-acetylglucosaminyltransferase (C3GnT) decreased 2 to 6- and 2-fold, respectively. Also, the expression of sialyltransferase, one of the mucin-glycan modifying enzymes, was decreased by 1-fold. Overall, our results indicate that the goblet cells/glycosyltransferase/O-glycan axis plays an important role in maintaining the physicochemical properties of colonic mucus and the stability of intestinal environment.

Exogenous Polyamines Influence In Vitro Microbial Adhesion to Human Mucus According to the Age of Mucus Donor

Adhesion to intestinal mucus is the first step for microbiota colonization in early life. Polyamines are polycations with important physiological functions in both procaryotic and eucaryotic cells. However, their role in intestinal mucus adhesion is not known. The objective of the present study was to evaluate whether exogenous polyamines (putrescine, spermidine, spermine, and their combination) would alter the adhesive properties of Lacticaseibacillus rhamnosus GG (LGG), Bifidobacterium animalis subs. lactis Bb12, Cronobacter sakazakii, and Escherichia coli. Human intestinal mucus was isolated from healthy infants (0-6-month-old and 6-12-month-old) and healthy adults (25-52 years old). Spermidine significantly increased Bb12 adhesion (p < 0.05) in the mucus of infants (0-6 months) but reduced the adhesion of LGG in adult mucus (p < 0.05) with no significant effect in any of the infant groups. Spermine was more effective than polyamine combinations in reducing C. sakazakii (p < 0.05) adhesion in early infant mucus (0-6 months). The adhesion ability of E. coli remained unaffected by exogenous polyamines at any age in the concentrations tested. Our data suggest that polyamines may modulate the bacterial adhesion to mucus depending on the bacterial strain and depending at what age the mucus has been generated.

Microbial Metabolites Determine Host Health and the Status of Some Diseases

The gastrointestinal (GI) tract is a highly complex organ composed of the intestinal epithelium layer, intestinal microbiota, and local immune system. Intestinal microbiota residing in the GI tract engages in a mutualistic relationship with the host. Different sections of the GI tract contain distinct proportions of the intestinal microbiota, resulting in the presence of unique bacterial products in each GI section. The intestinal microbiota converts ingested nutrients into metabolites that target either the intestinal microbiota population or host cells. Metabolites act as messengers of information between the intestinal microbiota and host cells. The intestinal microbiota composition and resulting metabolites thus impact host development, health, and pathogenesis. Many recent studies have focused on modulation of the gut microbiota and their metabolites to improve host health and prevent or treat diseases. In this review, we focus on the production of microbial metabolites, their biological impact on the intestinal microbiota composition and host cells, and the effect of microbial metabolites that contribute to improvements in inflammatory bowel diseases and metabolic diseases. Understanding the role of microbial metabolites in protection against disease might offer an intriguing approach to regulate disease.

Spermine: new insights into the intestinal development and serum antioxidant status of suckling piglets

The present work aimed at investigating the effects of spermine supplementation and extended spermine administration on the intestinal morphology, enzyme activity, and serum antioxidant capacity of suckling piglets.

Metabolomic strategy for the detection of metabolic effects of spermine supplementation in weaned rats

The purpose of this study is to examine the effects of spermine supplementation on weaned rat metabolism. A metabolomic strategy employing high-resolution (1)H NMR spectroscopy and multivariate data analysis was used to investigate rat biological responses to spermine ingestion. Rats received intragastric administration of either 0.2 or 0.4 μmol/g body weight of spermine or saline for 3 days. Plasma samples taken 48 h after the last spermine ingestion were analyzed. Spermine supplementation significantly increased the plasma levels of 1-methylhistidine, 3-hydroxybutyrate, alanine, glutamate, glycerolphosphocholine, phosphorylcholine, myo-inositol, phenylalanine, lysine, glutamine, trimethylanine, tyrosine, valine, formate, glucose, and lipids. These results suggest that spermine ingestion can alter common systemic metabolic processes, including cell membrane metabolism, lipid metabolism, glucose-alanine cycle metabolism, amino acid metabolism, and gut microbiota metabolism. This study also shows the important role of spermine administration in modulating the metabolism of weaned rats.

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.

Sialic acid is an essential nutrient for brain development and cognition

The rapid growth of infant brains places an exceptionally high demand on the supply of nutrients from the diet, particularly for preterm infants. Sialic acid (Sia) is an essential component of brain gangliosides and the polysialic acid (polySia) chains that modify neural cell adhesion molecules (NCAM). Sia levels are high in human breast milk, predominately as N-acetylneuraminic acid (Neu5Ac). In contrast, infant formulas contain a low level of Sia consisting of both Neu5Ac and N-glycolylneuraminic acid (Neu5Gc). Neu5Gc is implicated in some human inflammatory diseases. Brain gangliosides and polysialylated NCAM play crucial roles in cell-to-cell interactions, neuronal outgrowth, modifying synaptic connectivity, and memory formation. In piglets, a diet rich in Sia increases the level of brain Sia and the expression of two learning-related genes and enhances learning and memory. The purpose of this review is to summarize the evidence showing the importance of dietary Sia as an essential nutrient for brain development and cognition.

Composition of the non-protein nitrogen fraction of goat whole milk powder and goat milk-based infant and follow-on formulae

The non-protein nitrogen fraction of goat whole milk powder and of infant and follow-on formulae made from goat milk was characterized and compared with cow milk powder and formulae. Goat milk infant formula contained 10% non-protein nitrogen, expressed as a proportion of total nitrogen, compared with 7.1% for cow milk formula. Goat follow-on formula contained 9.3% and cow 7.4% non-protein nitrogen. Urea, at 30%, was quantitatively the most abundant component of the non-protein nitrogen fraction of goat milk and formulae, followed by free amino acids at 7%. Taurine, glycine and glutamic acid were the most abundant free amino acids in goat milk powders. Goat milk infant formula contained 4 mg/100 ml total nucleotide monophosphates, all derived from the goat milk itself. Goat milk has a very different profile of the non-protein nitrogen fraction to cow milk, with several constituents such as nucleotides at concentrations approaching those in human breast milk.

Polyamine homeostasis in arginase knockout mice

The role of ornithine decarboxylase (ODC) in polyamine metabolism has long been established, but the exact source of ornithine has always been unclear. The arginase enzymes are capable of producing ornithine for the production of polyamines and may hold important regulatory functions in the maintenance of this pathway. Utilizing our unique set of arginase single and double knockout mice, we analyzed polyamine levels in the livers, brains, kidneys, and small intestines of the mice at 2 wk of age, the latest timepoint at which all of them are still alive, to determine whether tissue polyamine levels were altered in response to a disruption of arginase I (AI) and II (AII) enzymatic activity. Whereas putrescine was minimally increased in the liver and kidneys from the AII knockout mice, spermidine and spermine were maintained. ODC activity was not greatly altered in the knockout animals and did not correlate with the fluctuations in putrescine. mRNA levels of ornithine aminotransferase (OAT), antizyme 1 (AZ1), and spermidine/spermine-N(1)-acetyltransferase (SSAT) were also measured and only minor alterations were seen, most notably an increase in OAT expression seen in the liver of AI knockout and double knockout mice. It appears that putrescine catabolism may be affected in the liver when AI is disrupted and ornithine levels are highly reduced. These results suggest that endogenous arginase-derived ornithine may not directly contribute to polyamine homeostasis in mice. Alternate sources such as diet may provide sufficient polyamines for maintenance in mammalian tissues.

Modulation of indomethacin-induced gastric injury by spermine and taurine in rats

This study investigated the involvement of neutrophil infiltration, nitric oxide (NO) generation, and oxidative stress in indomethacin-induced ulcer and the possible gastroprotective potentials of spermine and taurine, known for their tissue regenerating and antioxidant effects, respectively. Male Wistar albino rats (180-220 g) were allocated into a normal control group, ulcer control group (received a single dose of indomethacin 40 mg-kg p.o.), and two ulcer groups pretreated with spermine (150 mg-kg p.o. 1 h before ulcer induction) and taurine (250 mg-kg i.p. for three consecutive days before ulcer induction). The animals were killed 6 h after indomethacin administration, and the gastric juice, serum, and mucosal tissue were used for gastric injury evaluation. Both modulators significantly ameliorated the indomethacin-induced gastric lesions in glandular mucosa. Notably, spermine exhibited the most pronounced effect as manifested by great reduction in the gastric ulcer index, normalization of the elevated gastric acidity, and triggering of mucin production. Spermine and taurine were able to decrease the elevated levels of gastric myeloperoxidase, conjugated diene, and serum NO. However, the lowered tissue NO content was markedly elevated only by taurine. The antioxidant action of taurine was illustrated by restoration of the depressed content of glutathione, normalization of the inhibited activities of glutathione reductase, and superoxide dismutase. These results suggest that spermine and taurine confer significant gastroprotection against indomethacin-induced gastric injury with the priority of spermine.

The cell clone ecology hypothesis and the cell fusion model of cancer progression and metastasis (II): three pathways for spontaneous cell-cell fusion and escape from the intercellular matrix

The two-stage initiation-progression model of cancer is widely accepted. Initiation appears to result most often from accumulation of damage to the DNA expressed as multiple mutations in the phenotype. Unsymmetrical chromosome segregation during mitosis of normal or mutated cells produces aneuploid cells and also contributes to the evolution of neoplasia. However, it has been pointed out (Parris GE. Med Hypotheses 2005;65:993-4 and 2006;66:76-83) that DNA damage and loss of chromosomes are much more likely to lead the mutant clones of cells to extinction than to successful expansion (e.g., an example of Muller's Ratchet). It was argued that aneuploid neoplasia represent new parasite species that successfully evolve to devour their hosts by incorporating sex-like redistribution of chromosomes through spontaneous or virus-catalyzed cell-cell fusion into their life-cycle. Spontaneous cell-cell fusion is generally blocked by the intercellular matrix to which the cells are bound via surface adhesion molecules (frequently glycoproteins, e.g., CD44). In order for progression of matrix-contained neoplasia toward clinically significant cancer to occur, the parasite cells must escape from the matrix and fuse. Release from the matrix also allows the parasite cells to invade adjacent tissues and metastasize to remote locations. Both invasion and metastasis likely involve fusion of the migrating parasite cells with fusion-prone blast cells. There are at least three pathways through which parasite cells can be liberated from the confining matrix: (i) Their adhesion molecules may be modified (e.g., by hyper-glycosylation) so that they can no longer grip the matrix. (ii) Their adhesion molecules or matrix may be saturated with other ligands (e.g., polyamines). (iii) Their adhesion molecules may be cleaved from the cell surface or the matrix itself may be cleaved (e.g., by MMPs or ADAMs). It is hypothesized that mobilization of parasite cells and cell-cell fusion go hand-in-hand in the progression of neoplasia to clinically significant cancer through invasion and metastasis. The latency between tumor recognition and exposure to mutagens and the increased incidence of cancer with age can probably be related to slow breakdown of the intercellular matrix that provides a barrier to cell-cell fusion.

Differential effect of dietary spermine on alkaline phosphatase activity in jejunum and ileum of unweaned rats

Spermine is a low molecular weight polyamine involved in the postnatal maturation of the gut. When it is administered orally to suckling rats it induces the maturation of their spleen, liver, pancreas, and small intestine. We showed that this polyamine modulates differently the activity of alkaline phosphatase in jejunum and ileum in suckling rat. In 14-day-old rat which had received spermine orally for 3 days, once daily, an increase of alkaline phosphatase activity in the jejunum and a decrease of this activity in the ileum was observed. Alkaline phosphatase was located at the bottom of the villus in the control jejunum and in the whole length of the villus in spermine-treated rats. On the contrary, in ileum of controls, this enzyme was present in the whole length of the villus but disappeared in the spermine-treated animals. An enzyme mass shift was observed in the small intestine after spermine administration. Spermine administration did not change the expression of genes coding for alkaline phosphatase, suggesting a post-transcriptional modification.

Regulation of the intestinal glycoprotein glycosylation during postnatal development: role of hormonal and nutritional factors

This review focuses on the regulation of the glycoprotein glycosylation process in small intestine and colon during postnatal development. Glycoproteins play a prominent part in intestine as mucins secreted by the goblet cells and as molecules of biological interest largely present in the microvillus membrane of the enterocytes (digestive enzymes, transporters). The age-related changes in the intestinal glycosylation control the quality of glycan chains of glycoproteins. Postnatal maturation is observed at all stages of the glycoprotein glycosylation. But it is essentially characterised in the external glycosylation by a shift from sialylation to fucosylation depending on the transcriptional regulation of the corresponding glycosyltransferases, but also on coordinate changes in the activities of glycosyltransferases and of their regulatory proteins, in nucleotide-sugar bioavailability and in product degradation by oxidases. Many factors have been evoked to trigger these changes, among which are hormonal (glucocorticoids, insulin) and dietary factors. Changes in the structure of the glycoprotein glycans might be important for the transport, the barrier function, the implantation of the immune defences and of the microflora and even probably for the biological activity of some digestive enzymes.