Spermine-induced maturation in wistar rat intestine: a cytokine-dependent mechanism

Oral Spermine Supplementation in Gestated Rabbit: A Study on Villi Height of Immature Intestines

Introduction: Immature intestines are the major problem in prematurity. Postnatal oral spermine has been shown in studies to improve intestinal maturation in rats and piglets. This study aimed to find out the efficacy of spermine in rabbits during gestation. Method: An experimental study was done in an unblinded, randomized manner on those treated with and without spermine administration. A morphological examination of hematoxylin-eosin-stained villi was performed under a light microscope with a focus on villi height. Data were subjected to analysis. Results: The median of the spermine-treated group was found to be higher at 24, 26, and 28 days than the non-spermine group, but was not significantly different. Conclusion: Oral spermine supplementation during gestation might improve intestinal villi height in immature rabbit intestines.

Maturation of the Intestinal Epithelial Barrier in Neonatal Rats Coincides with Decreased FcRn Expression, Replacement of Vacuolated Enterocytes and Changed Blimp-1 Expression

BACKGROUND

The intestinal barrier is immature in newborn mammals allowing for transfer of bioactive macromolecules, e.g. protecting antibodies, from mother's milk to the blood circulation and in neonatal rodents lasts until weaning. This passage involves the neonatal-Fc-receptor (FcRn) binding IgG in the proximal and highly endocytic vacuolated enterocytes in the distal immature small intestine (SI). Recent studies have suggested an involvement of the transcription factor B-lymphocyte-induced maturation-protein-1 (Blimp-1) in the regulation of SI maturation in mice. Hence, the objective of the present study was to monitor the development of the intestinal barrier function, in relation to Blimp-1 expression during both natural and precociously induced intestinal maturation in rats.

RESULTS

During the suckling period IgG plasma levels increased, while after gut closure it temporarily decreased. This corresponded to a high expression of FcRn in the proximal SI epithelium and the presence of vacuolated enterocytes in the distal SI. The immature foetal-type epithelium was replaced after weaning or induced precocious maturation, by an adult-type epithelium with FcRnneg cells in the proximal and by non-vacuolated enterocytes in the distal SI. In parallel to this epithelial shift, Blimp-1 expression decreased in the distal SI.

CONCLUSION

The switch from foetal- to adult-type epithelium, with decreased proximal expression of FcRn and distal replacement of vacuolated enterocytes, was concurrent in the two SI regions and could be used for monitoring SI maturation in the rat. The changes in expression of Blimp-1 in the distal SI epithelium followed the maturation pattern.

Nutrimetabolomic analysis provides new insights into spermine-induced ileum-system alterations for suckling rats

This study aimed to investigate the effects of spermine supplementation on the ileum metabolism of suckling 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.

Immune suppression by cyclosporin A inhibits phytohemagglutinin-induced precocious gut maturation in suckling rats

OBJECTIVES

Enteral exposure to the lectin phytohemagglutinin (PHA) provokes precocious gut maturation in suckling rats coinciding with an early expansion of intestinal mucosal T and B lymphocytes. Here, the role of the immune system in neonatal gut growth and maturation was further studied.

MATERIALS AND METHODS

The effects of immunosuppression by cyclosporine A (CyA), 7.5 microg/g of body weight, injected 12 hours before and then daily after the intragastric gavage of PHA, 100 microg/g body weight, to 14-day-old suckling rats were studied after 4 and 12 hours and later after 72 hours.

RESULTS

At 4 hours after PHA feeding, an early rapid increase in the intestinal levels of the proinflammatory cytokines interleukin-6, interleukin-1beta, and tumor necrosis factor was obtained, and the CyA treatment did not prevent the temporary PHA-induced intestinal disturbance seen at 12 hours. Later, at 72 hours after PHA gavage the CyA treatment significantly counteracted the PHA-induced gut changes with a decrease in small intestinal growth, a delay in the appearance of adult-phenotype enterocytes in the distal small intestinal, and total inhibition of the PHA-induced pancreas development. Additionally, the increase in plasma level of the acute phase protein, haptoglobin, after PHA feeding was dampened by CyA.

CONCLUSIONS

The results indicate that proinflammatory cytokines are involved in the early recruitment of lymphocytes to the gut after PHA challenge, and that the ensuing precocious gut maturation is dependent on activation of the immune system, presumably T cells, in suckling rats.

Influence of breast milk polyamines on suckling rat immune system maturation

The aim of this study was to ascertain whether the supplementation of polyamines present in breast milk, i.e. spermine (SPM) and spermidine (SPD), influenced the post-natal maturation of the systemic and intestinal immune system in rats. From birth, pups daily received SPM or SPD. At 5, 11 and 18 days old, small intestine intraepithelial lymphocytes (IEL), lamina propria lymphocytes (LPL) and splenocytes were phenotypically characterized. SPM and, less evidently, SPD accelerated the maturation of CD8+ IEL, and enhanced the presence of intraepithelial NK cells and IEL related with specific immune responses on the proximal and distal small intestine, respectively. Polyamines increased the percentage of more mature CD4+ LPL and enhanced the early presence of splenic B cells and, later, that of NK cells. However, no effect on Ig-secretory function was detected. These results suggest that breast milk polyamines improve the maturation of the rat intestinal and systemic immune system.

Precocious gut maturation and immune cell expansion by single dose feeding the lectin phytohaemagglutinin to suckling rats

The dietary lectin phytohaemagglutinin (PHA) induces gut growth and precocious maturation in suckling rats after mucosal binding. The present study investigated the dose range in which PHA provokes gut maturation and if it coincided with immune activation. Suckling rats, aged 14 d, were orogastrically fed a single increasing dose of PHA: 0 (control), 2, 10, 50 or 250 microg/g body weight (BW) in saline. The effect on gut, lymphoid organs and appearance of CD3+ (T-lymphocyte) and CD19+ (B-lymphocyte) cells in the small-intestinal mucosa was studied at 12 h (acute) and 3 d (late phase) after treatment. The low PHA doses (2 and 10 microg/g BW) induced intestinal hyperplasia without mucosal disarrangement but did not provoke gut maturation. Only the high PHA doses (50 and 250 microg/g BW) temporarily disturbed the intestinal mucosa with villi shortening and decrease in disaccharidase activities, and later after 3 d provoked precocious maturation, resulting in an increase in maltase and sucrase activities and decrease in lactase activity and disappearance of the fetal vacuolated enterocytes in the distal small intestine. Exposure to the high, but not to the low, PHA doses increased the number of mucosal CD19+ and CD3+ cells in the small intestine after 12 h, a finding also observed in untreated weaned rats aged 21-28 d. In conclusion, there was a dose-related effect of PHA on gastrointestinal growth and precocious maturation that coincided with a rapid expansion of mucosal B- and T-lymphocytes, indicating a possible involvement of the immune system in this process.

Antioxidative properties of human milk and spermine are not related to expression of Hsp 70

AIM

Heat shock proteins (Hsps) have been detected in various tissues, including those in the intestines, and play a role in cellular protection. Polyamines, such as spermine (SPM), are found in human milk (HM) and act as antioxidants. We hypothesized that the antioxidative property of SPM is related to the expression of Hsp and examined this relationship in an intestinal epithelial cell (IEC) line.

METHOD

(i) Confluent IEC-6 cells were exposed to mild heat shock (43 degrees C, 1 h) and then allowed to recover at 37 degrees C for 24 h. Hydrogen peroxide (H(2)O(2)) was applied to induce oxidative stress and cell viability was evaluated. (ii) Cells were exposed to mild heat shock or pre-incubated with HM or pre-incubated with 5 microM SPM for 24 h. Hsp70 expression in IEC-6 cells was analysed by Western blot.

RESULTS

The survival rate of cells treated with mild heat shock after H(2)O(2) challenge was significantly higher than that of non-pretreated cells. Western blot analysis demonstrated that Hsp70 was expressed in IEC-6 cells treated with mild heat shock but not in IEC-6 cells pre-incubated with HM or 5 microM SPM.

CONCLUSION

Mild heat shock treatment induces Hsp70, which acts as an antioxidant in IEC-6 cells, but HM or SPM does not induce Hsp70 in this system.

Amine free crystal structure: the crystal structure of d(CGCGCG)2 and methylamine complex crystal

We succeeded in the crystallization of d(CGCGCG)2 and methylamine Complex. The crystal was clear and of sufficient size to collect the X-ray crystallographic data up to 1.0 A resolution using synchrotron radiation. As a result of X-ray crystallographic analysis of 2Fo-Fc map was much clear and easily traced. It is the first time monoamine co-crystallizes with d(CGCGCG)2. However, methylamine was not found from the complex crystal of d(CGCGCG)2 and methylamine. Five Mg ions were found around d(CGCGCG)2 molecules. These Mg ions neutralized the anion of 10 values of the phosphate group of DNA with five Mg2+. DNA stabilized only by a metallic ion and there is no example of analyzing the X-ray crystal structure like this. Mg ion stabilizes the conformation of Z-DNA. To use monoamine for crystallization of DNA, we found that we can get only d(CGCGCG)2 and Mg cation crystal. Only Mg cation can stabilize the conformation of Z-DNA. The method of using the monoamine for the crystallization of DNA can be applied to the crystallization of DNA of long chain of length in the future like this.

Enterally but Not Parenterally Administered Phaseolus vulgaris Lectin Induces Growth and Precocious Maturation of the Gut in Suckling Rats

BACKGROUND

The lectin, phytohemagglutinin (PHA) has been shown to induce growth and functional maturation of the gastrointestinal (GI) tract in suckling rats.

OBJECTIVES

To investigate the effect of the administration route, and whether enteral exposure to PHA was necessary to induce functional maturation.

METHODS

Fourteen-day-old rats were daily administered PHA via orogastric feeding (0.05 mg PHA/g BW) or via subcutaneous injection (0.05 or 0.005 mg PHA/g BW) for 3 days, while the controls received saline orogastrically. At 17 days of age, organ weight, intestinal and pancreatic function, and plasma corticosterone levels were analyzed. Moreover, 14-days old pups receiving a single dose of PHA, enterally or parenterally, were sacrificed after 12 h and examined for organ PHA binding using immunohistochemistry.

RESULTS

Enteral PHA exposure resulted in PHA binding in the epithelial lining of the small intestine, increased gastrointestinal growth, reduced intestinal macromolecular absorption, altered the disaccharidase expression towards an adult-like pattern, and increased the pancreatic protein and trypsin contents. In contrast, parenteral PHA exposure (high dose) resulted in PHA-binding in extra-intestinal organs, increased liver and spleen weight, and decreased thymus weight. Moreover, the intestinal maltase activity increased moderately, and the transfer of BSA to blood plasma was partially reduced. Both PHA treatments led to elevated plasma corticosterone levels.

CONCLUSION

These results demonstrated that enteral exposure to PHA was necessary to induce the precocious maturation of the GI tract and the pancreas, while parenteral administration affects the extra-intestinal organs. Furthermore, the enteral effects were probably not mediated via a corticosteroid dependent pathway.

Intestinal effects of long-lasting spermine ingestion by suckling rats

Spermine ingestion induces the precocious maturation of the small intestine in suckling rats. Previous observations suggest that spermine-induced intestinal maturation is a two-step phenomenon. The first step is the elimination of immature enterocytes (4-10 h post spermine ingestion) and the second step is the replacement of previous immature cells by adult-type enterocytes (2-3 days post initial spermine administration). The spermine-induced maturation is reversible when spermine administration is stopped. This work was undertaken in order to check whether the extension of polyamine administration (for 3-7 days) after the appearance of spermine-induced maturation can retain the mature state of the small intestine. Our results indicate that extension of spermine administration does not prevent some parameters (sucrase and maltase specific activities) reverting to a typical 'immature' value while others remain at a typical 'mature' level (mucosal weight and lactase specific activity). Our results show that there are at least two different mechanisms in required for the control of spermine-induced maturation of the small intestine.

Effects of human milk and spermine on hydrogen peroxide-induced oxidative damage in IEC-6 cells

OBJECTIVE

Oxidative stress is intimately involved in the pathologic processes of serious diseases in the perinatal period. Human milk (HM) contains various bioactive substances, some of which are known as antioxidants, including polyamines such as spermine (SPM). We examined the antioxidative properties of HM and SPM in an intestinal epithelial cell line.

METHOD

Confluent Intestinal Epithelial Cells-6 (IEC-6) cells were preincubated with 100-fold dilutions of defatted HM, bovine milk, or three artificial milks for 24 hours, followed by hydrogen peroxide (H2O2) challenge (0.5 mM, 30 min) for oxidative stress. Cells were preincubated with either HM or increasing concentrations (within the range of HM) of SPM for 24 hours followed by an H2O2 challenge (0.25 mM, 30 min).

RESULTS

HM-treated cells showed the highest survival rate (50%) compared with no pretreatment (27%), bovine milk-treated (6%), or artificial formula-treated (13-16%) cells. Significantly higher survival rates were observed in the cells treated with HM (44.0%) and in those treated with 0.5, 1, or 5 microM of SPM (12.6, 13.1, or 22.2%, respectively) in comparison with the nontreated cells (7.0%).

CONCLUSION

Our results demonstrated that HM and SPM alleviated H2O2-induced oxidative damage in IEC-6 cells, whereas bovine milk and artificial formula did not show any antioxidative capacity. These results suggest that HM acts as an antioxidant in the gastrointestinal tract of infants and that SPM plays an important role in the antioxidative properties of HM.

Enhancement of lysozyme stability and activity by polyamines

Spermine, a low molecular weight polyamine, administered orally to suckling rats induces the maturation of the small intestine. In this organ, lysozyme is an important component of the innate immunity. In this report, we analysed the binding of spermine to lysozyme and its effect on thermal inactivation of the protein by spectroscopy techniques. The activity of the enzyme was analysed in presence of spermine by lysoplate technique. We studied the effects of spermine ingestion by suckling rats on intestinal lysozyme activity and gene expression. We reported that spermine binds to lysozyme and increases in vitro the thermal stability and the activity of the protein. When administered orally to suckling rats, spermine increases the lysozyme activity in jejunum, but not in ileum. This increase is not due to a modification of the gene expression. The observed effects lead us to postulate that spermine could be used in some mammals as a promoter of the innate immunity.

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.