Spermine protects aluminium chloride and iron-induced neurotoxicity in rat model of Alzheimer's disease via attenuation of tau phosphorylation, Amyloid-β (1-42) and NF-κB pathway

Alzheimer's disease (AD) is the most prevalent type of dementia, characterized by a gradual decline in cognitive and memory functions of the aged peoples. Long-term exposure to heavy metals (aluminium and iron) cause neurotoxicity by amyloid plaques accumulation, tau phosphorylation, increased oxidative stress, neuroinflammation, and cholinergic neurons degeneration, contributes to the development of AD-like symptoms. The present research work is designed to investigate the neuroprotective effect of spermine in aluminium chloride (AlCl₃), and iron (Fe) induced AD-like symptoms in rats. Rats were administered of AlCl₃ (100 mg/kg p.o.) alone and in combination with iron (120 μg/g, p.o.) for 28 days. Spermine (5 and 10 mg/kg) through intraperitoneal (i.p.) route was given for 14 days. The recognition and spatial memory impairment were tasted using Morris water maze (MWM), actophotometer, and Novel Object Recognition test (NORT). All the rats were sacrificed on day 29, brains were isolated, and tissue homogenate was used for neuroinflammatory, biochemical, neurotransmitters, metals concentration, and nuclear factor-kappa B (NF-κB) analysis. In the present study, AlCl₃ and iron administration elevated oxidative stress, cytokines release, dysbalanced neurotransmitters concentration, and biochemical changes. Rats treated with spermine dose-dependently improved the recognition and spatial memory, attenuated proinflammatory cytokine release, and restored neurotransmitters concentration and antioxidant enzymes. Spermine also mitigated the increased beta-amyloid (Aβ42), with downregulation of tau phosphorylation. Furthermore, spermine augmented the hippocampal levels of B cell leukaemia/lymphoma-2 (Bcl-2), diminished nuclear factor-kappa B (NF-κB) and caspase-3 (casp-3) expression. Moreover, spermine exhibited the neuroprotective effect through anti-inflammatory, antioxidant, neurotransmitters restoration, anti-apoptotic Aβ42 concentration.

Aspirin enhances sensitization to the egg-white allergen ovalbumin in rats

Enhancement of oral absorption of food allergens by non-steroidal anti-inflammatory drugs (NSAIDs), especially aspirin, is considered an exacerbating factor in the development of food allergies. In this study, we examined the effect of aspirin on oral sensitization to and absorption of the egg-white allergen ovalbumin (OVA) in rats. The absorption of OVA was evaluated by measuring the plasma concentration of OVA after oral administration by gavage. To evaluate oral sensitization to OVA, plasma levels of immunoglobulin (Ig) E and IgG₁ antibodies (Abs) specific to OVA were determined by enzyme-linked immunosorbent assay after initiation of sensitization. High-dose aspirin (30 mg/kg) increased oral OVA absorption and plasma levels of OVA-specific IgE and IgG₁ Abs compared with those observed in vehicle-treated rats. In contrast, low-dose aspirin (3 mg/kg) exerted no changes in either absorption or sensitization. Spermine, an absorption enhancer, increased the oral absorption of OVA to nearly the same extent as high-dose aspirin, whereas the plasma levels of OVA-specific IgE and IgG₁ Abs exhibited no significant differences between spermine- and vehicle-treated rats. Among the NSAIDs, diclofenac and indomethacin increased sensitization to OVA, similar to high-dose aspirin, but meloxicam exerted no effects on Ab levels. In conclusion, we showed that high-dose aspirin enhanced oral sensitization to OVA. Our study suggests that enhanced oral sensitization to OVA cannot be ascribed to increased absorption of OVA from the intestinal tract. Although the mechanisms underlying this enhancement of sensitization are still controversial, our study suggests that modification of cytokine production due to impairment of the intestinal barrier function and inhibition of cyclooxygenase-1 activity by aspirin may be involved.

Suppression of Tobacco Carcinogen-Induced Lung Tumorigenesis by Aerosol-Delivered Glycerol Propoxylate Triacrylate-Spermine Copolymer/Short Hairpin Rab25 RNA Complexes in Female A/J Mice

BACKGROUND

Rab25, a member of Rab family of small guanosine triphosphatase, is associated with progression of various types of human cancers, including lung cancer, the leading cause of cancer-associated deaths around the globe.

METHODS

In this study, we report the gene therapeutic effect of short hairpin Rab25 RNA (shRab25) on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in female A/J mice. Initially, mice (6 weeks old) were injected with single dose of NNK (2 mg/0.1 mL saline/mouse) by intraperitoneal injection to induce the tumor. Eight weeks later, shRab25 was complexed with glycerol propoxylate triacrylate-spermine (GPT-SPE) copolymer and delivered into tobacco-induced lung cancer models through a nose-only inhalation system twice a week for 2 months.

RESULTS

GPT-SPE/shRab25 largely decreased the tobacco-induced tumor numbers and tumor volume in the lungs compared to GPT-SPE- or GPT-SPE/shScr-delivered groups. Remarkably, aerosol-delivered GPT-SPE/shRab25 significantly decreased the expression level of Rab25 and other prominent apoptosis-related proteins in female A/J mice. The apoptosis in these mice was determined by detecting the expression level of Bcl-2, proliferating cell nuclear antigen, Bax, and further confirmed by TUNEL assay.

CONCLUSIONS

Our results strongly confirm the tumorigenic role of Rab25 in tobacco carcinogen-induced lung cancer and hence demonstrate aerosol delivery of shRab25 as a therapeutic target for lung cancer treatment.

Self-immolative nanoparticles for simultaneous delivery of microRNA and targeting of polyamine metabolism in combination cancer therapy

Combination of anticancer drugs with therapeutic microRNA (miRNA) has emerged as a promising anticancer strategy. However, the promise is hampered by a lack of desirable delivery systems. We report on the development of self-immolative nanoparticles capable of simultaneously delivering miR-34a mimic and targeting dysregulated polyamine metabolism in cancer. The nanoparticles were prepared from a biodegradable polycationic prodrug, named DSS-BEN, which was synthesized from a polyamine analog N1,N11-bisethylnorspermine (BENSpm). The nanoparticles were selectively disassembled in the cytoplasm where they released miRNA. Glutathione (GSH)-induced degradation of self-immolative linkers released BENSpm from the DSS-BEN polymers. MiR-34a mimic was effectively delivered to cancer cells as evidenced by upregulation of intracellular miR-34a and downregulation of Bcl-2 as one of the downstream targets of miR-34a. Intracellular BENSpm generated from the degraded nanoparticles induced the expression of rate-limiting enzymes in polyamine catabolism (SMOX, SSAT) and depleted cellular natural polyamines. Simultaneous regulation of polyamine metabolism and miR-34a expression by DSS-BEN/miR-34a not only enhanced cancer cell killing in cultured human colon cancer cells, but also improved antitumor activity in vivo. The reported findings validate the self-immolative nanoparticles as delivery vectors of therapeutic miRNA capable of simultaneously targeting dysregulated polyamine metabolism in cancer, thereby providing an elegant and efficient approach to combination nanomedicines.

Neuroprotective effects of Kukoamine A against cerebral ischemia via antioxidant and inactivation of apoptosis pathway

Kukoamine A (KuA) is a bioactive compound, which is known for a hypotensive effect. Recent studies have shown that KuA has anti-oxidative effect and anti-apoptosis stress in vitro. However, its neuroprotective effect in rats with cerebral ischemia is still unclear. In the study, we investigated whether KuA could attenuate cerebral ischemia induced by permanent middle cerebral artery occlusion (pMCAO) in rats. Results revealed that KuA could significantly reduce infarct volume both pre-treatment and post-treatment, and increase corresponding Garcia neurological scores. Acute KuA postconditioning not only significantly reduced cerebral infarct volume, brain water content and improved neurological deficit scores, but also decreased the number of TUNEL-positive cells. Moreover, it markedly increased the activities of Cu/Zn-SOD and Mn-SOD, reduced levels of MDA and H₂O_2. Increased expressions of caspase-3, cytochrome c and the ratio of Bax/Bcl-2 were significantly alleviated with KuA treatment. These findings demonstrated that KuA was able to protect the brain against injury induced by pMCAO via mitochondria mediated apoptosis signaling pathway.

Implication of the polyamines in the neurotoxic effects ofN-methyl-D-aspartate

N-Methyl-D-aspartate (NMDA) receptor activation selectively releases the polyamines spermine and spermidine from the rat striatum in vivo. The intrastriatal injection of spermine or spermidine is neurotoxic, but this toxicity is not blocked by MK-801 and unlikely to be mediated via the NMDA receptor. The neurotoxic effects of intrastriatally injected NMDA can, however, be reduced by polyamine synthesis inhibition with difluoromethylornithine. Alterations in polyamine metabolism in the ischaemic brain, although perhaps induced by NMDA receptor activation, may contribute to ischaemic cell loss via NMDA-independent mechanisms, possibly related to the diverse effects of polyamines on calcium homoeostasis and channel function.

Functionalized magnetic dextran-spermine nanocarriers for targeted delivery of doxorubicin to breast cancer cells

In recent decades, targeted drug delivery systems for breast cancer treatment emerged as an ideal alternative and promising solution to reduce systemic side effects of chemotherapeutic agents. In this study, the preparation and characterization of cationic doxorubicin (DOX) loaded magnetic dextran-spermine (DEX-SP) nanocarriers (DEX-SP-DOX) by ionic gelation were fully investigated. Then, anti-HER2 as a monoclonal antibody (mAb) and targeting ligand was conjugated via EDC/NHS reagents. The binding was confirmed by Bradford assay and further assessments were carried out by size and zeta potential measurements. Cytotoxicity effect and internalization of magnetic nanocarriers were assessed by MTT and Prussian blue assays and transmission electron microscopy (TEM), respectively. DLS measurements indicated that the size of nanocarriers increased from 62 to 84 nm by conjugation of anti-HER2 to them. The in vitro release of DOX from mAb conjugated magnetic nanocarriers at pHs 5 and 7.4 was found to be 85 and 55.5%, respectively. The MTT and Prussian blue assays demonstrated enhanced and selective uptake of DEX-SP-DOX-mAb by SKBR cell (HER2 overexpressed cells) in comparison with unconjugated nanocarriers due to higher cellular binding. The TEM result also confirmed cellular internalization of DEX-SP-DOX-mAb magnetic nanocarriers. These results are very promising for targeted delivery of DOX to HER2 positive breast cancer cells.

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.

Safety profile of dextran-spermine gene delivery vector in mouse lungs

A nano-sized polymer, dextran-spermine (D-SPM), was shown to have the capacity to deliver gene to the lung of mouse via intranasal route. In this study, assessments on the safety profile of D-SPM were performed to complement the gene expression results. African green monkey kidney fibroblast (COS-7) and human adenocarcinoma breast (MCF-7) cells transfected with D-SPM/pDNA showed massive reduction in the number of viable cells. As for in vivo study, elevated level of neutrophils was observed, despite the minimal level of pro-inflammatory cytokines (TNF-alpha, IL-12, IFN-gamma) detected in the bronchoalveolar lavage fluid (BALF) of mice treated with the D-SPM/pDNA complexes. Histology profile examinations of the lungs showed mild inflammatory responses, with inflamed areas overlap with healthy areas. Although reduction of mice weight was seen at day 1 post administration, the mice did not show any sign of abnormal behavior or physical appearance. Biodistribution study was performed to determine the ability of the D-SPM/pDNA complexes to infiltrate to other non-intended organs. The result showed that the D-SPM/pDNA complexes were only localized at the lung and no gene expression was detected in other organs or blood. In short, these results indicate that the D-SPM/pDNA exhibited mild toxicity in the mouse lungs.

The role of the polyamine catabolic enzymes SSAT and SMO in the synergistic effects of standard chemotherapeutic agents with a polyamine analogue in human breast cancer cell lines

INTRODUCTION

Polyamine analogues have demonstrated significant activity against human breast cancer cell lines as single agents as well as in combination with other cytotoxic drugs. This study evaluates the ability of a polyamine analogue N (1),N (11)-bis(ethyl)norspermine (BENSpm) to synergize with six standard chemotherapeutic agents, 5-fluorouracil (FU), fluorodeoxyuridine, cis-diaminechloroplatinum(II) (C-DDP), paclitaxel, docetaxel, and vinorelbine.

MATERIALS AND METHODS

Four human breast cancer cell lines (MDA-MB-231, MCF-7, Hs578t, and T47D) and one immortalized, non-tumorigenic mammary epithelial cell line (MCF-10A) were used for in vitro combination studies with BENSpm and cytotoxic drugs. Xenograft mice models generated with MDA-MB-231 cells were used for in vivo studies with BENSpm and paclitaxel.

RESULTS AND CONCLUSION

BENSpm exhibited synergistic inhibitory effect on cell proliferation in combination with 5-FU or paclitaxel in human breast cancer cell lines (MDA-MB-231 and MCF-7) and was either antagonistic or less effective in the non-tumorigenic MCF-10A cell line. Synergism was highest with 120 h concomitant treatment or pre-treatment with BENSpm for 24 h followed by concomitant treatment for 96 additional hours. Since the cytotoxic effects of many polyamine analogues and cytotoxic agents are believed to act, in part, through induction of the polyamine catabolic enzymes SSAT and SMO, the role of these enzymes on synergistic response was evaluated in MDA-MB-231 and MCF-7 treated with BENSpm and 5-FU or paclitaxel. Combination treatments of BENSpm with 5-FU or paclitaxel resulted in induction of SSAT mRNA and activity in both cell lines compared to either drug alone, while SMO mRNA and activity were increased only in MDA-MB-231 cells. Induction was greater with BENSpm/paclitaxel combination than BENSpm/5-FU. Further, RNAi studies demonstrated that both SSAT and SMO play a significant role in the response of MDA-MB-231 cells to treatment with BENSpm and 5-FU or paclitaxel. In MCF-7 cells, only SSAT appears to be involved in the response to these treatments. In an effort to translate combination studies from in vitro to in vivo, and to form a basis for clinical setting, the in vivo therapeutic efficacy of BENSpm alone and in combination with paclitaxel on tumor regression was evaluated in xenograft mice models generated with MDA-MB-231 cells. Intraperitoneal exposure to BENSpm or taxol singly and in combination for 4 weeks resulted in significant inhibition in tumor growth. These findings help elucidate the mechanisms involved in synergistic drug response and support combinations of polyamine analogues with chemotherapeutic agents which could potentially be used in the treatment of breast cancer.

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.

Novel oral absorption system containing polyamines and bile salts enhances drug transport via both transcellular and paracellular pathways across Caco-2 cell monolayers

The combinatorial use of spermine (SPM), a typical polyamine, and sodium taurocholate (STC), a typical bile salt, was found to be a promising safe preparation for improving the oral absorption of poorly water-soluble and/or poorly absorbable drug in our previous studies utilizing rats and dogs. To clarify the mechanisms behind the synergistic enhancement effect of the polyamine and bile salt, the transport of rebamipide, which is classified into Biopharmaceutics Classification System Class IV, was investigated in Caco-2 cell monolayers. The synergistic enhancement of rebamipide transport by SPM and STC was certainly observed in Caco-2 cells as well, while the separate use of either SPM or STC did not significantly improve the transport of rebamipide. The combinatorial use of SPM and STC significantly decreased the transepithelial electrical resistance (TEER) in Caco-2 cell monolayers, suggesting that the opening of paracellular pathway. On the other hand, it was also confirmed that the decrease in TEER was transient and reversible after removal of SPM and STC and that cell viability was maintained. Voltage-clamp study clearly showed that their combinatorial use improved rebamipide transport via both paracellular and transcellular pathways, and that the contribution of transcellular route could be larger than paracellular route.

Intrathecal infusion of a Ca(2+)-permeable AMPA channel blocker slows loss of both motor neurons and of the astrocyte glutamate transporter, GLT-1 in a mutant SOD1 rat model of ALS

Elevated extracellular glutamate, resulting from a loss of astrocytic glutamate transport capacity, may contribute to excitotoxic motor neuron (MN) damage in ALS. Accounting for their high excitotoxic vulnerability, MNs possess large numbers of unusual Ca(2+)-permeable AMPA channels (Ca-AMPA channels), the activation of which triggers mitochondrial Ca(2+) overload and strong reactive oxygen species (ROS) generation. However, the causes of the astrocytic glutamate transport loss remain unexplained. To assess the role of Ca-AMPA channels on the evolution of pathology in vivo, we have examined effects of prolonged intrathecal infusion of the Ca-AMPA channel blocker, 1-naphthyl acetylspermine (NAS), in G93A transgenic rat models of ALS. In wild-type animals, immunoreactivity for the astrocytic glutamate transporter, GLT-1, was particularly strong around ventral horn MNs. However, a marked loss of ventral horn GLT-1 was observed, along with substantial MN damage, prior to onset of symptoms (90-100 days) in the G93A rats. Conversely, labeling with the oxidative marker, nitrotyrosine, was increased in the neuropil surrounding MNs in the transgenic animals. Compared to sham-treated G93A animals, 30-day NAS infusions (starting at 67+/-2 days of age) markedly diminished the loss of both MNs and of astrocytic GLT-1 labeling. These observations are compatible with the hypothesis that activation of Ca-AMPA channels on MNs contributes, likely in part through oxidative mechanisms, to loss of glutamate transporter in surrounding astrocytes.

[Dextran-spermine polycation as a vector for gene transfection in vitro]

This work reports the properties of dextran-spermine polycation (DSP) as a gene vector and its gene transfection efficiency in vitro. Oxidized dextran was reacted by reductive amination with spermine to obtain DSP, the resulted polycation was then incubated with plasmid pEGFP to form polyplexes by electrostatic interactions. DSP formed stable polyplexes when the weight ratio (DSP/DNA) varied from 4 : 1 to 20 : 1. The particle size and zeta potential of polyplexes were in the range of 162.6 - 187.9 nm and increased from + 8.45 mV to + 39.6 mV, respectively. DSP could effectively protect condensed DNA from DNase I degradation, and it showed strong buffering capacity in a certain pH range. The highest yields of transfection efficiency were found to be as high as Lipofectamine 2000 when the polyplexes were transfected to SMMC-7721 and BHK-21 cells at the weight ratio of 8 : 1. This research indicates that dextran-spermine polycation is a highly active gene vector in vitro.

Development of a polyamine database for assessing dietary intake

Reducing the concentration of polyamines (spermine, spermidine, and putrescine) in the body pool may slow the cancer process. Because dietary spermine, spermidine, and putrescine contribute to the body pool of polyamines, quantifying them in the diet is important. Limited information about polyamine content of food is available, especially for diets in the United States. This brief report describes the development of a polyamine database linked to the Fred Hutchinson Cancer Center food frequency questionnaire (FFQ). Values for spermine, spermidine, and putrescine were calculated and reported per serving size (nmol/serving). Of the foods from the database that were evaluated, fresh and frozen corn contain the highest levels of putrescine (560,000 nmol/serving and 902,880 nmol/serving) and spermidine (137,682 nmol/serving and 221,111 nmol/serving), and green pea soup contains the highest concentration of spermine (36,988 nmol/serving). The polyamine database and FFQ were tested with a convenience sample (n=165). Average daily polyamine intakes from the sample were: 159,133 nmol/day putrescine, 54,697 nmol/day spermidine, and 35,698 nmol/day spermine. Orange and grapefruit juices contributed the greatest amount of putrescine (44,441 nmol/day) to the diet. Green peas contributed the greatest amount of spermidine (3,283 nmol/day) and ground meat contributed the greatest amount of spermine (2,186 nmol/day). Development of this database linked to an FFQ provides a means of estimating polyamine intake and contributes to investigations relating polyamines to cancer.

Dose-Dependent Effects of a Nitric Oxide Donor in a Rat Flap Model

Previous studies have proven the effectiveness of nitric oxide (NO) donors to enhance flap survival in experimental models. The purpose of this study was to determine the ideal dose of the NO donor spermine/nitric oxide complex (Sper/NO) with respect to flap survival and hemodynamic side effects. Additionally, the influence of the type of application (systemically versus intra-arterial into the flap artery) was observed.Seventy-two male Wistar rats were divided into 9 experimental groups. An extended epigastric adipocutaneous flap (6 x 10 cm) based on the left superficial epigastric artery and vein was raised in each animal. The average percentage of flap necrosis was 69.8% in the control group with ischemia and 29.8% in the non ischemic controls. The average necrosis areas in the 3 groups after preischemic intravenous (i.v.) application of Sper/NO (250, 500, and 750 nmol/kg body weight) were 63.5%, 33.8%, and 38.4%, respectively. The application of similar doses into the flap artery resulted in 63.5%, 72.3%, and 64.3% flap necrosis; 52.7% average flap loss was observed in an additional group receiving Sper/NO adjusted to flap weight (500 nmol/kg flap weight). Only the intravenous application of 500 and 750 nmol/kg resulted in a significant reduction of flap necrosis compared with the ischemic controls (P < 0.01). The drop in mean arterial pressure was less after i.v. application of 500 nmol/kg Sper/NO compared with 750 nmol. Our data show that the preischemic intravenous application of 500 nmol/kg Sper/NO achieved the best results with acceptable side effects. A dose of 250 nmol/kg i.v., as well as the application of Sper/NO into the flap artery, was demonstrated to be ineffective.

Expression profile of plasmid DNA by spermine derivatives of pullulan with different extents of spermine introduced

The objective of this study is to prepare a novel gene carrier from pullulan, a polysaccharide with an inherent affinity for the liver, and evaluate the feasibility in gene transfection. Various amounts of spermine were chemically introduced into pullulan with molecular weights of 22,800, 47,300, and 112,000 to prepare cationized pullulan derivatives with different percentages of spermine introduced. Each cationized pullulan derivative was complexed with a plasmid DNA at various ratios and applied to HepG2 cells for in vitro gene transfection. The level of gene expression depended on the percent spermine introduced of cationized pullulan derivatives and the molecular weight of pullulan. However, when compared at the complexation molar ratio of pullulan derivative to the plasmid DNA, the expression level became maximum around the ratio of 10(2), irrespective of the pullulan molecular weight. Pre-treatment of cells with asialofetuin of asialoglycoprotein receptor ligand decreased the level of gene expression by the complexes. The cationized pullulan derivative with an appropriate physicochemical character is a promising non-viral carrier which promotes the receptor-mediated internalization of plasmid DNA and consequently enhances the expression level.

Characterization and in vivo performance of dextran-spermine polyplexes and DOTAP/cholesterol lipoplexes administered locally and systemically

In this study, we compared two systems which can be applied for transfection in vitro and in vivo: polyplexes based on the polymer dextran-spermine (D-SPM) and lipoplexes based on 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/cholesterol. The carriers differ in (1) solubility in aqueous media, (2) source of the positive charges (quaternary amines for DOTAP and primary plus secondary amines for D-SPM), (3) electrostatics, i.e., for lipid and polymer, respectively: zeta-potential (81.0 and 48.1 mV), surface potential (180 and 92 mV), and surface pH (10.47 and 8.97), and (4) charge distribution (ordered versus non-ordered). The stability of the complex upon interaction with serum proteins was studied by means of fluorescence resonance energy transfer (FRET) between rhodamine-labeled cationic carriers and fluorescein-labeled DNA. Addition of serum increases the lipid-DNA average distance and decreases the polymer-DNA distance. However, FRET efficiency indicates that serum proteins do not induce a major DNA dissociation for either polyplexes or lipoplexes. Comparing the biodistribution of rhodamine-labeled complexes and the transgene expression after intravenous (i.v.), intramuscular (i.m.), and intranasal (i.n.) administration, we found that local administration of lipoplexes resulted in the lipoplexes remaining at the site of injection, whereas the polyplexes showed systemic distribution, accompanied by transgene expression in lungs and liver. It is suggested that the high water-solubility of the polymer combined with its lower positive charge (compared to DOTAP), which makes its association with the cells at the site of injection weaker, enables the polymer to reach and transfect distant organs through the blood stream. Using chemically modified D-SPM, we demonstrated the importance of high density of positive charges and a sufficient level of secondary amines for achieving efficient transgene expression in vivo.

Effects of a sperminated gelatin on the nasal absorption of insulin

The effects of a sperminated gelatin (SG), which was prepared as a candidate absorption enhancer by the addition of spermine to gelatin, on the nasal absorption of insulin, were examined in rats. The AUC of immuno-reactive insulin levels in the plasma after nasal administration of insulin were increased 5.3-fold by addition of 0.2% SG, and the plasma glucose levels fell in a manner dependent on the insulin levels. In Calu-3 cell monolayer permeation experiments, SG showed significant enhancing effects on 5(6)-carboxyfluorescein (CF), FITC-dextran (MW 4400, FD4) and insulin. Evaluation of the tight junctions in the Calu-3 cell monolayers based on the Renkin molecular sieving function suggests that the pore occupancy/length ratio of the permeation pathways for water-soluble molecules in the tight junctions increases, while the equivalent cylindrical pore radius is not changed by SG treatment. SG may transform the true tight junctions, which act as a barrier for water-soluble molecules, into pathways for CF and FD4 to increase their number. SG is a good candidate for a safe absorption enhancer to produce a slight modification of the permeability of the paracellular pathway of mucosal membranes, while retaining the sieving property of the epithelial membranes.

Dendrons with spermine surface groups as potential building blocks for nonviral vectors in gene therapy

This paper investigates a series of dendrons based on the Newkome dendritic scaffold that displays a naturally occurring polyamine (spermine) on their surface. These dendrons have previously been shown to interact with DNA in a generation dependent manner with the more highly branched dendrons exhibiting a strong multivalency effect for the spermine surface groups. In this paper, we investigate the ability of these dendrons to transfect DNA into cells (human breast carcinoma cells, MDA-MB-231, and murine myoblast cells, C2C12) as determined by the luciferase assay. Although the dendrons are unable to transfect DNA in their own right, they are capable of delivering DNA in vitro when administered with chloroquine, which assists with escape from endocytic vesicles. The cytotoxicity of the dendrons was determined using the XTT assay, and it was shown that the dendrons were nontoxic either alone or in the presence of DNA. However, when administered with DNA and chloroquine, the most highly branched dendron did exhibit some cytotoxicity. This paper elucidates the relationship between in vitro transfection efficiency and toxicity. While transfection efficiencies are modest, the low toxicity of the dendrons, both in their own right, and in the presence of DNA, provides encouragement that this type of building block, which has a relatively high affinity for DNA, will provide a useful starting point for the further synthetic development of more effective gene transfection agents.

Effects of divalent cations and spermine on the K+ channel TASK-3 and on the outward current in thalamic neurons

The potassium channels TASK-1 and TASK-3 show high sequence homology but differ in their sensitivity to extracellular divalent cations. Heterologous expression in HEK293 cells showed that the single-channel conductance of TASK-3 increased approximately four-fold after removal of external divalent cations, whereas the conductance of TASK-1 was unaffected. Replacing the glutamate at position 70 of TASK-3 by a lysine or arginine residue abolished the sensitivity to divalent cations. The reverse mutation in TASK-1 (K70E) induced sensitivity to divalent cations. The organic polycations spermine and ruthenium red modulated the conductance of TASK-3 in a similar way as Ca2+ or Mg2+. Our data suggest that these effects were mediated by shielding of the negative charges in the extracellular loops of TASK-3. Whole-cell currents carried by TASK-3 channels were inhibited by spermine and ruthenium red even in the presence of external divalent cations. These data suggest that, in addition to their effect on single-channel conductance, spermine and ruthenium red decreased the open probability of TASK-3 channels, probably by binding to residue E70. The standing outward current in thalamocortical relay neurons, which is largely carried by TASK channels, was also inhibited by divalent cations and spermine. Using the differential sensitivity of TASK-1 and TASK-3 to divalent cations and spermine we found that about 20% of the standing outward current in thalamocortical relay neurons flows through TASK-3 channels. We conclude from our results that inhibition of TASK-3 channels may contribute to the neuromodulatory effect of spermine released from neurons during repetitive activity or during hypoxia.

Novel oral formulation safely improving intestinal absorption of poorly absorbable drugs: Utilization of polyamines and bile acids

In order to develop a novel oral formulation that can safely improve the intestinal absorption of poorly absorbable drugs, polyamines such as spermine (SPM) and spermidine (SPD) was examined as an absorption enhancing adjuvant in rats. The absorption of rebamipide, classified into BCS Class IV, from colon was significantly improved by SPM or SPD, and the enhancing ability of SPM was larger than that of SPD. As a possible mixing and/or interaction of polyamines with bile acids were expected, the combinatorial use of sodium taurocholate (STC) with polyamines was also examined. The absorption of rebamipide was drastically improved by the combinatorial use of SPM or SPD with STC. As STC itself did not enhance the absorption of rebamipide so much, it was considered that polyamines and STC had a synergistic enhancing effect. In-vivo oral absorption study was also performed to investigate the effectiveness and safety of polyamines and their combinatorial use with STC in rats. Although the enhancing effect slightly attenuated comparing with the in-situ loop study, the absorption of rebamipide was significantly improved and the combinatorial use of 10 mM SPM with 25 mM STC showed the largest enhancing effect. Histopathological studies clearly showed that any significant change in stomach and duodenum was not caused by SPM (10 mM), SPD (10 mM) or their combinatorial use with STC (25 mM) at 1.5 or 8.0 h after oral administration. Taken all together, polyamines, especially SPM, and its combinatorial use with STC could improve the absorption of poorly absorbable drugs without any significant changes in gastrointestinal tract after oral administration in rats.

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.

Modulation of intestinal urea cycle by dietary spermine in suckling rat

Argininosuccinate synthetase, an ubiquitous enzyme in mammals, catalyses the formation of argininosuccinate, the precursor of arginine. Arginine is recognised as an essential amino acid in foetuses and neonates, but also as a conditionally essential amino acid in adults. Argininosuccinate synthetase is initially expressed in enterocytes during the developmental period, it disappeared from this organ then appeared in the kidneys. Although the importance of both intestinal and renal argininosuccinate synthetases has been recognised for a long time, nutrients have not yet been identified as inducers of the gene expression. In the context of a proteomic screening of intestinal modifications induced by dietary spermine in suckling rats, we showed that argininosuccinate synthetase and carbamoyl phosphate synthase disappeared from enterocytes after this treatment. The disappearance of argininosuccinate synthetase in small intestine was confirmed by immunodetection. Expression of carbamoyl phosphate synthase and argininosuccinate synthetase coding genes decreased also after spermine administration. Expression of other urea cycle enzyme coding genes was modulated by spermine administration: argininosuccinate lyase decreased and arginase increased. Our results fit with the developmental variation of argininosuccinate synthetase and carbamoyl phosphate synthase. Modulation of the gene expression for several urea cycle enzymes suggests a coordination between all the pathway steps and switch toward polyamine (or proline and glutamate) biosynthesis from ornithine.

The pre-ischaemic neuroprotective effects of N1-dansyl-spermine in a transient focal cerebral ischaemia model in mice

The pre-ischaemic neuroprotective potential of a novel polyamine/NMDA antagonist N1-dansyl-spermine (1-5 mg kg(-1)) was studied in a transient focal cerebral ischaemia model in mice in comparison to a reference compound, MK-801 (1 or 3 mg kg(-1)). The intraluminal suture transient middle cerebral artery occlusion (MCAO) model was used. N1-dansyl-spermine and MK-801 were administered (i.p.) 30 min prior to ischaemia. A range of histological and behavioural assessments was employed. N1-dansyl-spermine had a comparable effect to MK-801 at reducing the percentage hemisphere lesion volume (%HLV) at the doses tested. Furthermore, N1-dansyl-spermine reduced the ischaemic brain oedema, which MK-801 did not. N1-dansyl-spermine significantly reversed the decrease of locomotor activity (LMA) caused by the MCAO and showed a significant effect at improving the rotarod performance impaired by MCAO. In contrast, MK-801 had no beneficial effect on sensorimotor function and even worsened the LMA. These results clearly demonstrate the pre-ischaemic neuroprotective effect of N1-dansyl-spermine in a transient focal cerebral ischaemia model.

Polyamine-vectored iron chelators: the role of charge

The utility of polyamines as vectors for the intracellular transport of iron chelators is further described. Consistent with earlier results with polyamine analogues, these studies underscore the importance of charge in the design of polyamine-vectored chelators. Four polyamine conjugates are synthesized, two of terephthalic acid [N(1)-(4-carboxy)benzoylspermine (7) and its methyl ester (6)] and two of (S)-2-(2,4-dihydroxyphenyl)-4,5-dihydro-4-methyl-4-thiazolecarboxylic acid [(S)-4'-(HO)-DADFT] [(S)-4,5-dihydro-2-[2-hydroxy-4-(12-amino-5,9-diazadodecyl-oxy)phenyl]-4-methyl-4-thiazolecarboxylic acid (10) and its ethyl ester (9)]. These four molecules were evaluated in murine leukemia L1210 cells for their impact on cell proliferation (48- and 96-h IC(50) values), their ability to compete with spermidine for the polyamine transport apparatus (K(i)), and their intracellular accumulation. The data revealed that when neutral molecules (cargo fragments) were fixed to the polyamine vector, the conjugates competed well with spermidine for transport and were accumulated intracellularly to millimolar levels. However, this was not the case when the cargo fragments were negatively charged. Metabolic studies of the polyamine-vectored (S)-4'-(HO)-DADFTs in rodents indicated that not only did the expected deaminopropylation step occur, but also a surprisingly high level of oxidative deamination at the terminal primary nitrogens took place. Finally, the iron-clearing efficiency of the (S)-4'-(HO)-DADFT conjugates was determined in a bile-duct-cannulated rodent model. Attaching the ligand to a polyamine vector had a profound effect on increasing the iron-clearing efficiency of this chelator relative to its parent drug.

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.

Effects ofN1,N13-Diethylnorspermine (DENSPM) and X-Radiation Treatment on Human Colorectal Tumor Clones with Varying X-Radiation and Drug Responses

This study was designed to examine the effects of treatment with N1, N13-diethylnorspermine (DENSPM), a spermine analog, and X radiation on survival and on the polyamine and spermidine/spermine N1-acetyltransferase (SSAT) levels in closely related human colorectal tumor (HCT116) clones exhibiting a wide range of X-radiation and drug responses. After treatment with DENSPM and X radiation, clonogenic cell survival was measured. SSAT protein levels were measured by Western blot analysis and SSAT enzymatic activities by the conversion of [1-14C]acetyl-CoA into [1-14C]acetylspermidine. Polyamine [i.e. putrescine (PUT), spermine (SPM) and spermidine (SPD)] levels were measured with high-performance liquid chromatography. DENSPM enhanced the efficacy of radiation treatment in HCT116, HCT116-Clone2 (a radiation-resistant clone) and HCT116-Clone10 (a clone with similar X-radiation response as the parental HCT116 cells) but not in HCT116-CloneK (an X-radiation-sensitive but relatively drug-resistant clone). Treatment with DENSPM without X radiation caused the most significant increase in SSAT activity (approximately 22-fold) and an almost complete depletion of SPD levels in HCT116-CloneK. Our results suggest that (a) the lack of sensitization of X-radiation treatment by DENSPM in HCT116-CloneK was likely due to the prior depletion of SPD levels by DENSPM alone, (b) natural polyamine contents and/or inducibility of SSAT may be important factors influencing cellular response to combined X-radiation and DENSPM treatments, and (c) more importantly, there may be a potentially novel role for combining polyamine analogs such as DENSPM with X rays.

Uptake of putrescine and spermidine by Gap1p on the plasma membrane in Saccharomyces cerevisiae

It has been reported that Gap1p on the plasma membrane of Saccharomyces cerevisiae can catalyze the uptake of many kinds of amino acids. In the present study, we found that Gap1p also catalyzed the uptake of putrescine and spermidine, but not spermine. The Km and Vmax values for putrescine and spermidine were 390 and 21 microM, and 4.6 and 0.59 nmol/min/mg protein, respectively. The uptake of putrescine was strongly inhibited by basic amino acids, lysine, arginine, and histidine, whose Ki values were 25-35 microM. Thus, it is deduced that spermidine and basic amino acids have almost the same affinity for Gap1p. When the concentrations of amino acids in the medium were reduced to one-third and 0.5 mM putrescine or 0.1 mM spermidine was added to the medium, accumulation of putrescine or spermidine by Gap1p was observed. Furthermore, when yeast was transformed with the GAP1 gene and cultured in the presence of 60 mM putrescine, cell growth was inhibited through overaccumulation of putrescine. GAP1 mRNA was found to be induced by polyamines. This is the first report of the identification, at a molecular level, of a polyamine uptake protein on the plasma membrane in eukaryotes.

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.

Control of Spermidine and Spermine Levels in Rat Tissues by trans-4-Methylcyclohexylamine, a Spermidine-Synthase Inhibitor

In rat tissues, a decrease in spermidine, accompanied by an increase in spermine was induced by the oral administration (once daily for either 1 week or 1 month) of trans-4-methylcyclohexylamine (4MCHA), a spermidine synthase inhibitor. This is similar to the changes observed in polyamine content when cell growth is arrested. The body-weight gain of the rats tended to decrease with increasing doses of 4MCHA. A decrease in spermidine, combined with a moderate increase in spermine, was observed dose-dependently in all of the tissues tested, with a relatively fast clearance of 4MCHA. Manipulating the polyamine content of tissues, by daily administration of 100 mumol 4MCHA for 1 week, made it possible to estimate the effects of simultaneously added spermidine or spermine on endogenous polyamine contents. The altered polyamine levels, obtained after daily administration for 1 week, were maintained during the extended 1-month period, with growth-dependent alteration. The results show it is possible to produce experimental rats with a higher spermine:spermidine ratio than control rats to investigate the physiological significance of spermidine downregulation and spermine upregulation in vivo.

A Polysaccharide Carrier for Immunostimulatory CpG DNAs To Enhance Cytokine Secretion‖

A beta-(1 --> 3)-d-glucan schizophyllan (SPG) forms a stoichiometric complex with some polynucleotides. This communication describes our attempt to apply the SPG complex to deliver CpG DNA to endosomes to enhance cytokine secretion. To increase cellular uptake, we introduced spermine, arginine-glycine-aspartic acid tripeptide, octaarginine, or cholesterol to the SPG side chain. The chemically modified SPG showed essentially no cytotoxicity. When CpG DNA complex made therefrom was exposed to macrophages, dramatic enhancement in the cytokine secretion was observed. It increased 5-10 times from the naked dose and 100 times from the background. This performance promises that SPG can be an excellent carrier for CpG DNA.

Short-term effects of spermine ingestion on the small intestine: a comparison of suckling and weaned rats

We have previously shown that spermine, shortly after its ingestion, can induce the alteration of the morphology of the small intestine of suckling rats. It was proposed that this alteration is due to polyamine accumulation inside the epithelial cells. This could also be related to the fact that the intestine of the suckling rat is in an immature state. To shed light on this issue, disaccharidase and alkaline phosphatase activity assays, protein, DNA and RNA content measurements and polyamine concentration analysis were performed on the small intestine of suckling and weaned Wistar rats treated with spermine. Spermine did not induce the same intestinal alterations in weaned rats compared to suckling animals. Indeed, in sucklings, spermine administration induced a decrease of the protein, DNA, putrescine and spermidine intestinal content, suggesting a cell loss. The cell loss impaired the activity of intestinal enzymes: lactase, maltase and alkaline phosphatase. In weaned rats, the same treatment did not alter these parameters. Exogenous spermine by itself is not sufficient to induce the alterations described here and previously. The maturity degree of the small intestine could be the basis of this process.

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

OBJECTIVES

Polyamines are of great importance in biologic processes such as cell proliferation and differentiation. The ingestion of spermidine or spermine by suckling rats induces the precocious maturation of the small intestine. In a previous article, the authors hypothesized that this phenomenon could be mediated by interleukins. This work was performed to examine the role of IL-1, IL-2, and tumor necrosis factor (TNF)- alpha in the spermine-induced maturation of the small intestine.

METHODS

Wistar suckling rats were treated with spermine, FR167653 (inhibitor of IL-1beta/TNF-alpha production), IL-1beta/TNF-alpha neutralizing antibodies, lipopolysaccharide, or IL-2. Intestinal disaccharidase-specific activities, polyamine content, and IL-2 plasma concentration were analyzed. Comparisons were made with untreated control animals.

RESULTS

Spermine-induced maturation of the small intestine was decreased by FR167653 but not by the neutralizing antibodies. Lipopolysaccharide injection induced an increase in disaccharidase-specific activity. IL-2 induced a decrease of the intestinal lactase-specific activity. Spermine administration led to a similar decrease of lactase activity and to an increase of IL-2 plasma concentration.

CONCLUSIONS

The authors conclude that IL-1beta and TNF-alpha are involved in the spermine effects on maltase- and sucrase-specific activities and suggest that IL-2 is involved in the spermine-induced decrease of lactase activity.

Cationic corticosteroid for nonviral gene delivery

Delivery of plasmid DNA for gene therapy often provokes an inflammatory response that reduces transgene expression. Cationic lipids for lipofection lack pharmacological activity despite the hydrophobicity of many drug candidates that could be exploited. We report a one-step synthesis of a water-soluble, dexamethasone-spermine (DS) cationic lipid that has potent gene transfer capability in confluent endothelial cells when used with the neutral lipid, dioleoylphosphatidylethanolamine (DOPE). In contrast, unconjugated mixtures of dexamethasone, spermine, and/or DOPE have essentially no gene transfer activity. DS retains partial corticosteroid character as quantified by the rapid translocation of glucocorticoid receptor to the nucleus and by dose-dependent transactivation from a glucocorticoid response element. DS has anti-inflammatory activity in vivo in the mouse thioglycollate model of inflammation. In a mouse lung model, DS:DOPE resulted in significantly less interferon-gamma production at Day 1 and elevated transgene expression at Days 1 and 7 postintranasal instillation compared to DC-Chol:DOPE (sterol:DOPE:phosphate molar ratio of 1:1:1). Cationic pharmacophores such as DS represent a new approach to gene delivery and localized therapy.

Extracellular polyamines regulate fluid secretion in rat colonic crypts via the extracellular calcium-sensing receptor

BACKGROUND AND AIMS

Polyamines are essential for the normal postnatal development, maintenance, and function of gastrointestinal epithelia. The extracellular Ca(2+) (Ca(2+)(o)/nutrient)-sensing receptor is expressed on both luminal and basolateral membranes of colonocytes, and, in other cell systems, this receptor has been shown to respond to polyamines. Thus, the Ca(2+)-sensing receptor could provide a mechanism for modulation of colonocyte function by dietary and systemic extracellular polyamines. In the present study, we investigated the interaction of polyamines, particularly spermine, and extracellular Ca(2+) on second messenger generation by, and on function of, rat distal colonic crypts.

METHODS

Calcium-sensing receptor activation was assessed in colonic epithelial cells and intact crypts freshly isolated from distal colon by monitoring intracellular IP(3) and Ca(2+) accumulation using radioimmunoassay and Fluo-3 fluorometry, respectively. Interactions of extracellular Ca(2+) and spermine on regulation of both basal and forskolin-stimulated fluid transport were measured in crypts microperfused in vitro.

RESULTS

Polyamine (spermine > spermidine > putrescine)-mediated enhancement of intracellular D-myo-inositol 1,4,5-trisphosphate (IP(3)) and Ca(2+) accumulation required extracellular Ca(2+), and the EC(50) for extracellular Ca(2+)-mediated activation of the calcium-sensing receptor was reduced by polyamines. Extracellular spermine modulated both basal and forskolin-stimulated fluid secretion in perfused colonic crypts, and the EC(50) for spermine-induced reduction in forskolin-stimulated fluid secretion was inversely dependent on extracellular Ca(2+) (Ca(2+)(o)).

CONCLUSIONS

The interactions of extracellular Ca(2+) and polyamines on second messenger accumulation and fluid secretion support a role for the luminal and basolateral calcium-sensing receptors in mediating some of the effects of polyamines on distal colonic epithelial cells.

Rapid absorption of luminal polyamines in a rat small intestine ex vivo model

BACKGROUND AND AIM

Not only biosynthesis, but also uptake from the intestinal lumen, are important polyamine sources. However, there has been no information regarding dynamic polyamine transport in the small intestine. We evaluated polyamine uptake from the small intestine using a rat ex vivo model.

METHODS

The organ block consisting of the small intestine and blood vessels was used. The isolated small intestine was placed in a warmed saline bath and perfused in a non-circulating manner via the superior mesenteric artery. Radio-labeled putrescine, spermidine or spermine (7.4 x 104 Bq), with 1.0 mL of phosphate buffer saline (pH 7.4) was instilled into the jejunal lumen for 1 min. Blood samples from the portal vein were collected and sample radioactivity was determined. In another experiment, an immunohistochemical study of polyamine was performed.

RESULTS

After 14C-polyamine instillation, radioactivity in the portal vein samples immediately increased and then decreased gradually. The absorptive pattern did not differ among the three polyamines. The recovery rates from radioactivity at the portal vein among the three polyamines were approximately 61-76% during the initial 10 min after the administration of 14C-polyamine, and were not different from each other. Aminoguanidine, which inhibits putrescine degradation, significantly suppressed initial putrescine uptake and recovery percentage. The intraluminal administration of spermine caused an increase in the immunoreactivity of the spermine antibody in the intestinal villi.

CONCLUSION

Luminal polyamines were rapidly absorbed by the intestinal mucosa and then subsequently transferred into the portal vein using a rat ex vivo model. The prior administration of aminoguanidine significantly inhibited initial putrescine transport into the portal vein.

Antioxidant effect of polyamines on erythrocyte cell membrane lipoperoxidation after free-radical damage

This in vitro study determined the effect of three doses each (100, 500 and 1000 microm) of putrescine, spermidine and spermine on malondialdehyde (MDA) release in red blood cells (RBCs) from healthy individuals after hydrogen peroxide stimulation (10 mM). Twenty-two volunteers, 9 males and 13 females, aged 41.5 +/- 16.4 years, were studied. MDA was measured by thiobarbituric reaction (TBARs) and the results were calculated using epsilon = 1.56 x 10(5). The analysis of variance (ANOVA) demonstrated a statistically significant overall decrease in MDA release in the polyamine-exposed cells (p < 0.0001) when compared with unexposed cells. Individual analysis of each polyamine separately showed a 52% decrease in MDA release with added spermine and a 39.5% decrease with added spermidine (p < 0.001). No evaluable effect was found for putrescine. There was no correlation between the effect produced and the three doses of spermidine or spermine added, indicating a non dose-dependent action.

Reduction of Postoperative Adhesions by N,O-Carboxymethylchitosan and Spermine NONOate in Rats

BACKGROUND

Postsurgical adhesions can occur following virtually all types of surgery, resulting in serious clinical complications. Therefore, prevention of adhesions is an important goal of surgical practice. A rat uterine horn model was used to investigate the efficacy of N,O-carboxymethylchitosan (NOCC) and spermine NONOate (SPER/NO) alone and in combination in preventing adhesion formation.

METHODS

Sixty Wistar albino rats underwent bilateral uterine horn injury with a unipolar cautery. Study groups were as follows: (i) control group, no adjuvant therapy; and those with adjuvant applied, (ii) normal saline group, 2 ml of normal saline was given; (iii) NOCC group, 2 ml of 2% NOCC gel was given; (iv) SPER/NO group, 2 ml of SPER/NO (0.5 mg/ml) was given, and (v) NOCC plus SPER/NO group, 2 ml of 2% NOCC gel including SPER/NO (0.5 mg/ml) was given. After 14 days, all animals were euthanatized, and a standard adhesion scoring system including extent and severity scores was applied by a blinded examiner.

RESULTS

The extent score in NOCC plus SPER/NO group was significantly lower than those of control and normal saline groups (p < 0.05). The extent score in NOCC group was significantly lower than that of normal saline group (p < 0.05). The extent score in NOCC plus SPER/NO group was significantly lower than that of SPER/NO group (p < 0.05). The severity score was significantly lower in NOCC plus SPER/NO and NOCC groups than that of control group (p < 0.05). The severity score was significantly lower in NOCC plus SPER/NO group than that of SPER/NO group (p < 0.05).

CONCLUSIONS

Postoperative administration of NOCC gel and SPER/NO alone and especially in combination to the site of peritoneal injury reduces the formation of adhesions in the rat uterine horn model.

The role of pre-ischaemic application of the nitric oxide donor spermine/nitric oxide complex in enhancing flap survival in a rat model

Spermine/nitric oxide complex (Sper/NO) is a new nitric oxide (NO) donor with a long half-life providing controlled biological release of NO in vivo. The purpose of this study was to determine whether flap survival could be improved by pre-ischaemic or post-ischaemic intravenous administration of Sper/NO. We divided 37 male Wistar rats into four experimental groups. An extended epigastric adipocutaneous flap was raised in each animal. The mean area of flap necrosis was assessed for all groups on the fifth postoperative day, using planimetry software. The average area of flap necrosis was mean +/- s.d. = 68.2%+/-18.1% in the control group, and 29.7% +/- 13.3% in the non-ischaemic controls. The group with pre-ischaemic application of Sper/NO demonstrated an average flap necrosis of mean+/-s.d. = 11.2%+/-5.9%, whereas this increased to 59.2%+/-14.4% in the group receiving Sper/NO 5 min prior to reperfusion. The group with pre-ischaemic application of Sper/NO showed a significantly lower area of flap necrosis than either of the control groups or the group receiving Sper/NO just prior to reperfusion (P < 0.05). The group receiving Sper/NO just prior to reperfusion demonstrated a significantly higher mean area of flap necrosis than the non-ischaemic controls (P < 0.05), but did not differ significantly from the control group. Our data show that pharmacological preconditioning and enhancement of flap survival can be achieved by intravenous administration of Sper/NO. The application of Sper/NO at the end of the ischaemia period or in the early reperfusion period provides no protection against ischaemia-reperfusion injury.

Appetite suppression and weight reduction by a centrally active aminosterol

The rise in obesity and its complications has generated enormous interest in the regulation of feeding and body weight. We show that a spermine metabolite of cholesterol (MSI-1436) decreases body weight, specifically fat, by suppressing feeding and preventing the reduction in energy expenditure, hormonal changes, and patterns of neuropeptide expression normally associated with weight loss. MSI-1436 enters the brain after peripheral injection and is more potent when injected into the cerebral ventricle (intracerebroventricular [ICV]). Systemic or ICV MSI-1436 administration induced similar patterns of Fos immunoreactivity in the brain, especially the paraventricular hypothalamic nucleus (PVN). This brain region integrates neural signals from hypothalamic and brain stem nuclei and regulates feeding behavior, autonomic function, and neuroendocrine function. Microinjection of MSI-1436 into the PVN potently suppressed feeding and reduced body weight for several days. Unlike caloric restriction, MSI-1436 decreased mRNA levels of agouti-related peptide and neuropeptide Y in the hypothalamus. These findings indicate that MSI-1436 acts in the brain to regulate food intake and energy expenditure, likely through suppression of orexigenic hypothalamic pathways.

Effects of acetylcholine and spermineNONOate on erythrocyte hemorheologic and oxygen carrying properties

PURPOSE OF THE STUDY

To determine the effects of acetylcholine and spermineNONOate--a NO donor--on RBC membrane and oxygen carrying properties.

MATERIAL AND METHODS

Aliquots of venous blood from eleven healthy subjects were incubated with ACh 10(-3) M, ACh 10(-5) M, spermineNONOate 10(-5) M and spermineNONOate 10(-4) M. The following parameters were determined: erythrocyte aggregation and deformability, hematocrit, plasma pH, osmolality, K(+), Na(+), Ca(2+) concentrations, hemoglobin, oxyhemoglobin, carboxyhemoglobin and methemoglobin concentrations, oxygen saturation of hemoglobin, oxygen and carbon dioxide partial pressures and p50.

RESULTS

In presence of ACh there is an increase of erythrocyte deformability, decrease of erythrocyte aggregation, plasma pH, K(+) and Na(+) concentration, increase of Ca(2+) concentration and p50. In presence of spermineNONOate there is an increase of erythrocyte deformability, plasma pH, decrease of Na(+) and Ca(2+) concentration, increase of metHb concentration and decrease of p50.

CONCLUSION

Acetylcholine and spermineNONOate are able to induce changes on RBC membrane and oxygen carrying properties.

Polyamine participation in the maturation of glycoprotein fucosylation, but not sialylation, in rat small intestine

The aim of this study was to determine the role of polyamines in the diet-related maturation of the intestinal glycoprotein glycosylation during postnatal development in the rat. The activity of alpha-2,6-sialyltransferase and the sialylated forms of glycoproteins in the intestinal brush-border membranes were found to decrease considerably after weaning, in parallel with the intestinal level of putrescine. By contrast, the activity of alpha-1,2-fucosyltransferases, the mRNA levels for two alpha-1,2-fucosyltransferase genes, FTA and FTB, and the fucosylated forms of glycoproteins all increased after weaning, in parallel with the levels of spermidine and spermine. These results suggest a possible role of polyamines in the evolution of glycosylation. The treatment of suckling rats with spermidine or spermine reproduced the high intestinal levels of these polyamines corresponding to those normally found after weaning. After these treatments, a rise in the activity of the alpha-1,2-fucosyltransferase was observed, associated with a fall in alpha-L-fucosidase activity. The alpha-1,2-fucosyltransferase FTB gene was found to be regulated at the transcriptional level, but not by its inhibitor, fuctinin. The result of these variations was the precocious appearance of several alpha-1,2-fucoproteins, which are normally found in brush-border membranes after weaning. The treatment of suckling rats with putrescine, which induced only a transitory rise in intestinal putrescine, had a similar but weaker effect on the fucosylation process than spermidine or spermine, and treatment with ornithine was ineffective. alpha-2,6-Sialylation was not affected by any of the treatments. Spermidine and spermine turned out to be more effective than putrescine for intestinal glycoprotein fucosylation, but did not affect their sialylation. Spermidine and spermine, whose intestinal levels where found to increase at weaning time, may have been partly responsible for the natural evolution of the intestinal glycoprotein fucosylation that occurred during this period.

Polyamine effects on human myometrial contractility

OBJECTIVE

This study was undertaken to investigate the effects of the polyamine spermine on human uterine contractility.

STUDY DESIGN

Under physiologic conditions, an isometric tension recording was performed in isolated myometrial strips from biopsy specimens obtained at elective cesarean delivery (n = 24 specimens) and from premenopausal hysterectomy specimens (n = 6 specimens). The effects of spermine (1 micromol/L-10 mmol/L in cumulative doses) on spontaneous, agonist-induced myometrial contractions were measured, and dose response curves were constructed. The pD(2) (-log EC(50)) values and the maximal inhibition values achieved were compared for spontaneous and agonist-induced contractions.

RESULTS

Spermine exerted a potent relaxant effect on all spontaneous and agonist-induced myometrial contractions, with mean maximal inhibition values between 62.8% +/- 4.3% and 91.4% +/- 1.8% and pD(2) values between 2.66 +/- 0.23 and 4.01 +/- 0.20. Its inhibitory effect varied significantly with different contraction types (pD(2), P <.05; mean maximal inhibition, P <.001), and it was least potent on BAY K 8644-elicited contractions (pD(2), P <.05; mean maximal inhibition, P <.01).

CONCLUSION

The polyamine spermine exerts a potent relaxant effect on human uterine tissue. This effect appears to be mediated, at least partially, by calcium antagonism. Polyamines may play a role in the maintenance of uterine quiescence during pregnancy.

Hypertension in normotensive and hypertensive rats by spermine ingestion

Polyamines (putrescine, spermidine and spermine) play an important role in the development of hypertension and in the expression of atrial natriuretic peptide (ANP), a cardiac hormone involved in the regulation of blood pressure. Wistar Kyoto normotensive (WKY) and spontaneously hypertensive rats (SHR) were given spermine in drinking water (0.5%) for 15 days. The spermine intake elevated the blood pressures of both SHR and WKY rats and reduced the expression of ANP (Northern blotting) in the ventricles. ANP levels in the plasma determined by enzyme immunoassay (EIA) showed no changes in the levels of plasma ANP after spermine intake. An analysis of polyamines by high-pressure liquid chromatography showed that the levels of spermine and spermidine were elevated in SHR hearts. It was in SHR hearts alone that spermine intake was associated with increases in the levels of putrescine. The results suggest that spermine-induced increases in blood pressure may involve mechanisms other than ANP.

Functionally different AMPA-type glutamate receptors in morphologically identified neurons in rat superficial superior colliculus

In the superficial superior colliculus, a center of sensory processing related to visual salience, glutamate is used as a major excitatory neurotransmitter. alpha-Amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type glutamate receptors include a Ca(2+)-impermeable, outwardly rectifying type (type I) and a Ca(2+)-permeable, inwardly rectifying type (type II). To study the contribution of these AMPA receptor subtypes to visual sensory processing in the superior colliculus, we investigated the expression of these two types of AMPA receptors in six morphologically identified subgroups of neurons in the superficial superior colliculus by whole-cell recording using slice preparations of young (17-23 days old) and adult (60-68 days old) rats. Both outwardly and inwardly rectifying current responses were observed to pressure applied 10 mM kainate, a non-desensitizing AMPA receptor agonist. These currents were completely abolished by the selective AMPA receptor antagonist 1-(4-aminophenyl)-3-methylcarbamyl-4-methyl-7,8-methylenedioxy-3,4-dihydro-5H-2,3-benzodiazepine (100 microM). The type II receptor antagonist spermine (1 mM) suppressed inwardly rectifying responses. The degree of inward rectification was correlated with the ratio of suppression by spermine, and inversely correlated with estimated Ca(2+) permeability, indicating that the degree of rectification reflects the relative amount of co-expressed type I and type II receptors. An inwardly rectifying and spermine-sensitive AMPA component of excitatory postsynaptic currents was observed, suggesting involvement of type II receptors in synaptic transmission. Morphological analysis revealed that a substantial population of horizontal cells in both young and adult rats (n=31/53 and 15/17, respectively) and all wide field multipolar cells in adult rats (n=6) showed inwardly rectifying AMPA receptor responses. From these results we suggest that type I and type II AMPA receptors are co-expressed with varying ratios in individual neurons in the rat superficial superior colliculus, and that type II receptors are abundantly expressed in most horizontal cells and wide field multipolar cells. Since these neurons are putatively GABAergic inhibitory neurons and have wide dendritic trees, type II receptors may contribute to the regulation of remote inhibitory interaction in the visual field map in the the superficial superior colliculus.

Phase 1 study of N1-N11-diethylnorspermine (DENSPM) administered TID for 6 days in patients with advanced malignancies

This was a dose escalation Phase 1 trial designed to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLT) of DENSPM.

METHODS

Adult patients with refractory solid tumors were treated with DENSPM administered by intravenous infusion in 100 ml of normal saline over 30 minutes. The daily dose of DENSPM was divided into three equal doses administered approximately every eight hours for six days. Courses were repeated every 28 days.

RESULTS

Twenty-eight patients were enrolled in the study. Dose levels of DENSPM explored were 25 mg/m2/day (3 patients), 50 mg/m2/day (9 patients), 60 mg/m2/day (5 patients), 75 mg/m2/day (6 patients), 94 mg/m2/day (3 patients) and 118 mg/m2/day (2 patients). The DLT for DENSPM was central nervous system toxicity characterized by aphasia, ataxia, dizziness, vertigo and slurred speech occurring at dose levels > or = 94 mg/m2/day, which was also the MTD.

SAFETY

The most frequent drug-related adverse events were asthenia (9 patients), injection site reaction (6 patients) and anemia (6 patients). One patient was removed from the study due to CNS toxicity. There were no treatment-related deaths. No trends were observed regarding hematologic toxicities, biochemical changes or changes in vital signs.

EFFICACY

Nineteen of the 28 patients enrolled in the study were assessed for response. No objective responses were observed. Five patients had stable disease as the best response to therapy.

CONCLUSIONS

Because the DLT was CNS and because of the relatively low doses that could be safely administered on this schedule as compared with a once-a-day schedule, this regimen was not recommended for Phase 2.

Intrathecally administered spermine produces the scratching, biting and licking behaviour in mice

Intrathecal (i.t.) administration of spermine (0.1-10000 fmol), an endogenous polyamine, produced the behavioural response mainly consisting of biting and/or licking of the hindpaw along with a slight hindlimb scratching directed toward the flank in mice, which peaked at 5-15 min and almost disappeared at 30 min after an injection. The behaviour induced by spermine (10 pmol) was dose-dependently inhibited by intraperitoneal injection of morphine (0.125-0.5 mg/kg). The characteristic behaviour was also inhibited dose-dependently by i.t. co-administration of ifenprodil (62.5-4000 pmol), a competitive antagonist of the polyamine recognition site on N-methyl-D-aspartate (NMDA) receptor ion-channel complex, and D(-)-2-amino-5-phosphonovaleric acid (D-APV) (0.5-2 nmol) and 3-((+/-)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) (7. 8-500 pmol), the competitive NMDA receptor antagonists, and (5R, 10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,b]cycloheptene-5, 10-imine hydrogen maleate (MK-801) (0.5-4 nmol), an NMDA ion-channel blocker, but not by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA receptor antagonist. Both (2S, 3S)-[cis-2-(diphenylmethyl)-N-[(2-methoxyphenyl)-methyl]-1-azabicy clo [2.2.2]octane-3-amine] (CP-96,345), a non-peptidic neurokinin-1 (NK-1) receptor antagonist, and CP-96,344, its inactive 2R,3R enantiomer, inhibited spermine-induced behavioural response in a dose-dependent manner. However, [Tyr(6), D-Phe(7), D-His(9)]-substance P(6-11) (sendide) and [D-Phe(7), D-His(9)]-substance P(6-11), the selective antagonists for NK-1 receptors, were without affecting spermine-induced behaviour. These results indicate that spermine-induced behaviour is mediated through the polyamine recognition site on NMDA receptor ion-channel complex without the involvement of substance P system in the mouse spinal cord.

Polymeric-based perivascular delivery of a nitric oxide donor inhibits intimal thickening after balloon denudation arterial injury: role of nuclear factor-kappaB

OBJECTIVES

To examine the effect of a polymeric-based periadventitial delivery of a nitric oxide (NO)-releasing diazeniumdiolate, spermine/NO (SPER/NO), on balloon injury-induced neointimal hyperplasia in rat ileofemoral arteries.

BACKGROUND

Reduced local bioavailability and adverse side effects limit systemic administration of NO to modulate vascular response to injury.

METHODS

A polylactic-polyglycolic acid polymeric matrix containing 2.5% SPER/NO (w/w) was applied around the injured arteries. Quantitative histomorphometry was performed at day 14, proliferating cell nuclear antigen (PCNA) immunohistochemistry at day 3 to assess effects on smooth muscle proliferation and electrophoretic mobility shift assay to evaluate effects on transcription factor, nuclear factor-kappaB (NF-kappaB).

RESULTS

Treatment with SPER/NO reduced the intimal area (0.011 +/- 0.009 vs. 0.035 +/- 0.006 mm2 control, p < 0.01) and the intima to media ratio (0.089 +/- 0.062 vs. 0.330 +/- 0.057 control, p < 0.005). Spermine/nitric oxide produced a profound inhibition of PCNA-positive cells (>75%, p < 0.005) and significantly suppressed the injury-induced activation of NF-kappaB. Vascular cyclic guanosine monophosphate (cGMP) levels were elevated after treatment with the SPER/NO (0.28 +/- 0.03 vs. 0.17 +/- 0.02 pmol/mg tissue control, p < 0.01). The inhibitory effects on neointimal proliferation were localized to the site of application of SPER/NO and were not associated with any changes in platelet aggregation or bleeding time. Neither SPER nor polymer alone had any significant effects on any of the variables examined.

CONCLUSIONS

Polymeric-based perivascular delivery of a NO donor produces a marked localized inhibition of neointimal proliferation in balloon-injured arteries. This phenomenon is associated with suppression of NF-kappaB activation and elevation of the vascular cGMP at the site of injury.

Specific inhibition of macrophage TNF-alpha expression by in vivo ribozyme treatment

The overproduction of the cytokine TNF-alpha is associated with inflammatory and autoimmune diseases. We have developed a means to block TNF-alpha production with ribozymes directed against TNF-alpha mRNA to selectively inhibit its production in vitro and in vivo. Following cationic lipid-mediated delivery to peritoneal murine macrophages in culture, anti-TNF-alpha ribozymes were more effective inhibitors of TNF-alpha secretion than catalytically inactive ribozyme controls. Inhibition of TNF-alpha secretion was proportional to the concentration of ribozyme administered, with an IC50 of approximately 10 nM. After i.p. injection of cationic lipid/ribozyme complexes, elicited macrophages accumulated approximately 6% of the administered ribozyme. The catalytically active ribozyme suppressed LPS-stimulated TNF-alpha secretion by approximately 50% relative to an inactive ribozyme control without inhibiting secretion of another proinflammatory cytokine produced by macrophages, IL-1alpha. Ribozyme-specific TNF-alpha mRNA degradation products were found among the mRNA extracted from macrophages following in vivo ribozyme treatment and ex vivo stimulation. Thus, catalytic ribozymes can accumulate in appropriate target cells in vivo; once in the target cell, ribozymes can be potent inhibitors of specific gene expression.