Showing papers on "Agmatine published in 2022"

Putrescine and Its Metabolic Precursor Arginine Promote Biofilm and c-di-GMP Synthesis in Pseudomonas aeruginosa

Abstract: Pseudomonas aeruginosa, an opportunistic bacterial pathogen, can synthesize and catabolize several small cationic molecules known as polyamines. In several clades of bacteria, polyamines regulate biofilm formation, a lifestyle-switching process that confers resistance to environmental stress. The polyamine putrescine and its biosynthetic precursors, l-arginine and agmatine, promote biofilm formation in Pseudomonas spp. However, it remains unclear whether the effect is a direct effect of polyamines or occurs through a metabolic derivative. Here, we used a genetic approach to demonstrate that putrescine accumulation, either through disruption of the spermidine biosynthesis pathway or the catabolic putrescine aminotransferase pathway, promoted biofilm formation in P. aeruginosa. Consistent with this observation, exogenous putrescine robustly induced biofilm formation in P. aeruginosa that was dependent on putrescine uptake and biosynthesis pathways. Additionally, we show that l-arginine, the biosynthetic precursor of putrescine, also promoted biofilm formation but did so by a mechanism independent of putrescine or agmatine conversion. We found that both putrescine and l-arginine induced a significant increase in the intracellular level of bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) (c-di-GMP), a bacterial second messenger widely found in Proteobacteria that upregulates biofilm formation. Collectively these data show that putrescine and its metabolic precursor, arginine, promote biofilm and c-di-GMP synthesis in P. aeruginosa. IMPORTANCE Biofilm formation allows bacteria to physically attach to a surface, confer tolerance to antimicrobial agents, and promote resistance to host immune responses. As a result, the regulation of biofilm formation is often crucial for bacterial pathogens to establish chronic infections. A primary mechanism of biofilm promotion in bacteria is the molecule c-di-GMP, which promotes biofilm formation. The level of c-di-GMP is tightly regulated by bacterial enzymes. In this study, we found that putrescine, a small molecule ubiquitously found in eukaryotic cells, robustly enhances P. aeruginosa biofilm and c-di-GMP. We propose that P. aeruginosa may sense putrescine as a host-associated signal that triggers a lifestyle switch that favors chronic infection.

Plasma Polyamine Biomarker Panels: Agmatine in Support of Prostate Cancer Diagnosis

Abstract: Prostate cancer is the most frequent malignant tumour among males (19%), often clinically silent and of difficult prognosis. Although several studies have highlighted the diagnostic and prognostic role of circulating biomarkers, such as PSA, their measurement does not necessarily allow the detection of the disease. Within this context, many authors suggest that the evaluation of circulating polyamines could represent a valuable tool, although several analytical problems still counteract their clinical practice. In particular, agmatine seems particularly intriguing, being a potential inhibitor of polyamines commonly derived from arginine. The aim of the present work was to evaluate the potential role of agmatine as a suitable biomarker for the identification of different classes of patients with prostate cancer (PC). For this reason, three groups of human patients—benign prostatic hyperplasia (BPH), precancerous lesion (PL), and prostate cancer (PC)—were recruited from a cohort of patients with suspected prostate cancer (n = 170), and obtained plasma was tested using the LC-HRMS method. Statistics on the receiver operating characteristics curve (ROC), and multivariate analysis were used to examine the predictive value of markers for discrimination among the three patient groups. Statistical analysis models revealed good discrimination using polyamine levels to distinguish the three classes of patients. AUC above 0.8, sensitivity ranging from 67% to 89%, specificity ranging from 74% to 89% and accuracy from 73% to 86%, considering the validation set, were achieved. Agmatine plasma levels were measured in PC (39.9 ± 12.06 ng/mL), BPH (77.62 ± 15.05 ng/mL), and PL (53.31 ± 15.27 ng/mL) patients. ROC analysis of the agmatine panel showed an AUC of 0.959 and p ≤ 0.001. These results could represent a future tool able to discriminate patients belonging to the three different clinical groups.

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

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

The memory modulatory effect of agmatine in passive avoidance task coincides with alterations of hippocampal CaMKII-α and ERK signaling in mice.

Abstract: Agmatine is a polyamine suggested to act as a supposed neurotransmitter in the brain. Evidence has indicated that acute agmatine administration might modulate memory. The present study aimed to investigate the effect of repeated agmatine treatment on passive avoidance memory, hippocampal calcium-calmodulin-dependent protein kinase II-alpha (CaMKII-α), and Extracellular Signal-Regulated Kinase (ERK) signaling pathways in naive mice. Adult male NMRI mice were treated with agmatine (10, 20, 30, 40, and 80 mg/kg/ip) or saline for 11 days. Acquisition and retention tests of passive avoidance memory were performed on days 10 and 11, respectively. Following the memory retention test, the hippocampi were assessed for the levels of CaMKII-α and ERK using the western blotting technique. The results revealed the dose-dependent effect of agmatine on the passive avoidance memory. Accordingly, the memory was impaired in lower doses, but was improved in higher ones. Agmatine in none of the doses affected the nociception of the mice in tail-flick test. Furthermore, agmatine increased the phosphorylation of CaMKII-α and ERK in the hippocampus at memory enhancing doses, while ERK phosphorylation decreased following the impairing doses of agmatine. Thus, the dose-dependent effect of agmatine on memory might be related to its modulatory effect on CaMKII-α and ERK signal transduction, eventually regulating the memory process.

Agmatine Mitigates Inflammation-Related Oxidative Stress in BV-2 Cells by Inducing a Pre-Adaptive Response

Abstract: Neuroinflammation and microglial activation, common components of most neurodegenerative diseases, can be imitated in vitro by challenging microglia cells with Lps. We here aimed to evaluate the effects of agmatine pretreatment on Lps-induced oxidative stress in a mouse microglial BV-2 cell line. Our findings show that agmatine suppresses nitrosative and oxidative burst in Lps-stimulated microglia by reducing iNOS and XO activity and decreasing O2− levels, arresting lipid peroxidation, increasing total glutathione content, and preserving GR and CAT activity. In accordance with these results, agmatine suppresses inflammatory NF-kB, and stimulates antioxidant Nrf2 pathway, resulting in decreased TNF, IL-1 beta, and IL-6 release, and reduced iNOS and COX-2 levels. Together with increased ARG1, CD206 and HO-1 levels, our results imply that, in inflammatory conditions, agmatine pushes microglia towards an anti-inflammatory phenotype. Interestingly, we also discovered that agmatine alone increases lipid peroxidation end product levels, induces Nrf2 activation, increases total glutathione content, and GPx activity. Thus, we hypothesize that some of the effects of agmatine, observed in activated microglia, may be mediated by induced oxidative stress and adaptive response, prior to Lps stimulation.

Facile Amidation of Non-Protected Hydroxycinnamic Acids for the Synthesis of Natural Phenol Amides

Abstract: Phenol amides are bioactive compounds naturally present in many plants. This class of compounds is known for antioxidant, anti-inflammatory, and anticancer activities. To better understand the reactivity and structure–bioactivity relationships of phenol amides, a large set of structurally diverse pure compounds are needed, however purification from plants is inefficient and laborious. Existing syntheses require multiple steps, including protection of functional groups and are generally overly complicated and only suitable for specific combinations of hydroxycinnamic acid and amine. Thus, to facilitate further studies on these promising compounds, we aimed to develop a facile general synthetic route to obtain phenol amides with a wide structural diversity. The result is a protocol for straightforward one-pot synthesis of phenol amides at room temperature within 25 h using equimolar amounts of N,N′-dicyclohexylcarbodiimide (DCC), amine, hydroxycinnamic acid, and sodium bicarbonate in aqueous acetone. Eight structurally diverse phenol amides were synthesized and fully chemically characterized. The facile synthetic route described in this work is suitable for a wide variety of biologically relevant phenol amides, consisting of different hydroxycinnamic acid subunits (coumaric acid, ferulic acid, and sinapic acid) and amine subunits (agmatine, anthranilic acid, putrescine, serotonin, tyramine, and tryptamine) with yields ranging between 14% and 24%.

High-level production of the agmatine in engineered Corynebacterium crenatum with the inhibition-releasing arginine decarboxylase

Abstract: Agmatine is a member of biogenic amines and is an important medicine which is widely used to regulate body balance and neuroprotective effects. At present, the industrial production of agmatine mainly depends on the chemical method, but it is often accompanied by problems including cumbersome processes, harsh reaction conditions, toxic substances production and heavy environmental pollution. Therefore, to tackle the above issues, arginine decarboxylase was overexpressed heterologously and rationally designed in Corynebacterium crenatum to produce agmatine from glucose by one-step fermentation.In this study, we report the development in the Generally Regarded as Safe (GRAS) L-arginine-overproducing C. crenatum for high-titer agmatine biosynthesis through overexpressing arginine decarboxylase based on metabolic engineering. Then, arginine decarboxylase was mutated to release feedback inhibition and improve catalytic activity. Subsequently, the specific enzyme activity and half-inhibitory concentration of I534D mutant were increased 35.7% and 48.1%, respectively. The agmatine production of the whole-cell bioconversion with AGM3 was increased by 19.3% than the AGM2. Finally, 45.26 g/L agmatine with the yield of 0.31 g/g glucose was achieved by one-step fermentation of the engineered C. crenatum with overexpression of speAI534D.The engineered C. crenatum strain AGM3 in this work was proved as an efficient microbial cell factory for the industrial fermentative production of agmatine. Based on the insights from this work, further producing other valuable biochemicals derived from L-arginine by Corynebacterium crenatum is feasible.

Aspalathus linearis (Rooibos) and Agmatine May Act Synergistically to Beneficially Modulate Intestinal Tight Junction Integrity and Inflammatory Profile

Abstract: In order to promote gastrointestinal health, significant increases in the prevalence of gastrointestinal disorders should be paralleled by similar surges in therapeutics research. Nutraceutical interventions may play a significant role in patient management. The current study aimed to determine the potential of Aspalathus linearis (rooibos) to prevent gastrointestinal dysregulation resulting from high-dose trace-amine (TA) exposure. Considering the substantial female bias in functional gastrointestinal disorders, and the suggested phytoestrogenicity of rooibos, the study design allowed for a comparison between the effects of an ethanol extract of green rooibos and 17β-estradiol (E2). High levels of ρ-tyramine (TYR) and agmatine (AGM), but not β-phenethylamine (PEA) or tryptamine (TRP), resulted in prostaglandin E2 (PGE2) hypersecretion, increased tight-junction protein (TJP; occludin and ZO-1) secretion and (dissimilarly) disrupted the TJP cellular distribution profile. Modulating benefits of rooibos and E2 were TA-specific. Rooibos pre-treatment generally reduced IL-8 secretion across all TA conditions and prevented PGE2 hypersecretion after exposure to both TYR and AGM, but was only able to normalise TJP levels and the distribution profile in AGM-exposed cells. In contrast, E2 pre-treatment prevented only TYR-associated PGE2 hypersecretion and TJP dysregulation. Together, the data suggest that the antioxidant and anti-inflammatory effects of rooibos, rather than phytoestrogenicity, affect benefits illustrated for rooibos.

Thermogenic formation of biogenic amines during commercial coffee roasting processes

Abstract: This work shows the influences of free amino acids on the formation of related biogenic amines by thermal decarboxylation in an entire commercial roasting process. Two different C. arabica bean samples were investigated, which differed in terms of origin, variety, altitude and post-harvest process. The formation and degradation pattern of investigated amino acids and biogenic amines was comparable in both different bean samples. For the first time, the intermediate and thermogenic driven formation of histamine and agmatine were shown in the roasting process. Agmatine was formed in two different intensities. Histidine degradation and histamine formation showed molar conversion rates of 90% (Brazilian sample, semi-washed) and 95.6% (Kenyan sample, wet processed), whereas arginine was decarboxylated to agmatine in two steps, with rates of I: 23.5% and 29.8%, and II: 47.3% and 46.6%, respectively. No significant formation of putrescine, ethylamine, ethanolamine, tyramine, tryptamine, cadaverine, phenylethylamine, octopamine and ornithine could be found. The comparison to lab-scale roasting trials in the past offered varying results in regard to the changes of spermidine and histamine in the commercial batches of this study.

Thermogenic formation of biogenic amines during commercial coffee roasting processes

Abstract: This work shows the influences of free amino acids on the formation of related biogenic amines by thermal decarboxylation in an entire commercial roasting process. Two different C. arabica bean samples were investigated, which differed in terms of origin, variety, altitude and post-harvest process. The formation and degradation pattern of investigated amino acids and biogenic amines was comparable in both different bean samples. For the first time, the intermediate and thermogenic driven formation of histamine and agmatine were shown in the roasting process. Agmatine was formed in two different intensities. Histidine degradation and histamine formation showed molar conversion rates of 90% (Brazilian sample, semi-washed) and 95.6% (Kenyan sample, wet processed), whereas arginine was decarboxylated to agmatine in two steps, with rates of I: 23.5% and 29.8%, and II: 47.3% and 46.6%, respectively. No significant formation of putrescine, ethylamine, ethanolamine, tyramine, tryptamine, cadaverine, phenylethylamine, octopamine and ornithine could be found. The comparison to lab-scale roasting trials in the past offered varying results in regard to the changes of spermidine and histamine in the commercial batches of this study.

Exogenous application of agmatine improves water stress and salinity stress tolerance in turnip (Brassica rapa L.)

Abstract: This study was carried out to determine the consequence of foliar application of agmatine (0 and 0.5 mM), on growth, physiological and biochemical traits, and yield of turnip (Brassica rapa L.) plants grown under water stress or salt stress conditions. The effect of three irrigation regimes (100%, 80% and 40% of field capacity) and three salt concentrations (0, 100 and 200 mM NaCl) on turnip plants grown in pots under greenhouse conditions were studied. Water deficit developed at 40% Field capacity (FC) and salinity stress, especially at 200 mM, resulted in significant decreases in all growth parameters when compared to control plants (100% FC) including root length and diameter as well as shoot weights per plant. Water stress and high salt stress negatively affected most physiological and biochemical characteristics such as total chlorophyll, photosynthetic rate, stomatal conductance, and transpiration rate. Water use efficiency (WUE) increased under 80% FC or 100 mM NaCl. Antioxidant enzymes activity, catalase and peroxidase and glutathione reductase, increased with water stress and salt stress. Foliar application of agmatine seemed to alleviate the adverse effects of water stress and salt stress on turnip. Alleviating harmful effects of salt stress and enhancing water stress tolerance by agmatine was associated with improving leaf gas exchange, antioxidant enzymes and protein profile.

Alkaline Stress Causes Changes in Polyamine Biosynthesis in Thermus thermophilus

Abstract: An extreme thermophile, Thermus thermophilus, produces 16 different polyamines including long-chain and branched-chain polyamines. The composition and content of polyamines in the thermophile cells change not only with growth temperature but also with pH changes. In particular, cell growth decreased greatly at alkaline medium together with significant changes in the composition and content of polyamines. The amounts of tetraamines (spermine and its homologs) markedly decreased at alkaline pH. Thus, we knocked out the speE gene, which is involved in the biosynthesis of tetraamines, and changes of composition of polyamines with pH changes in the mutant cells were studied. Cell growth in the ΔspeE strain was decreased compared with that of the wild-type strain for all pHs, suggesting that tetraamines are important for cell proliferation. Interestingly, the amount of spermidine decreased and that of putrescine increased in wild-type cells at elevated pH, although T. thermophilus lacks a putrescine synthesizing pathway. In addition, polyamines possessing a diaminobutane moiety, such as spermine, decreased greatly at high pH. We assessed whether the speB gene encoding aminopropylagmatine ureohydrolase (TtSpeB) is directly involved in the synthesis of putrescine. The catalytic assay of the purified enzyme indicated that TtSpeB accepts agmatine as its substrate and produces putrescine due to the change in substrate specificity at high pH. These results suggest that pH stress was exacerbated upon intracellular depletion of polyamines possessing a diaminobutane moiety induced by unusual changes in polyamine biosynthesis under high pH conditions.

Effects of imidazoline agents in a rat conditioned place preference model of addiction

Abstract: Agmatine (AG), idazoxan (IDZ), and efaroxan (EFR) are imidazoline receptor ligands with beneficial effects in central nervous system disorders. The present study aimed to evaluate the interaction between AG, IDZ, and EFR with an opiate, tramadol (TR), in a conditioned place preference (CPP) paradigm. In the experiment, we used five groups with 8 adult male Wistar rats each. During the condition session, on days 2, 4, 6, and 8, the rats received the drugs (saline, or TR, or IDZ and TR, or EFR and TR, or AG and TR) and were placed in their least preferred compartment. On days 1, 3, 5, and 7, the rats received saline in the preferred compartment. In the preconditioning, the preferred compartment was determined. In the postconditioning, the preference for one of the compartments was reevaluated. TR increased the time spent in the non-preferred compartment. AG decreased time spent in the TR-paired compartment. EFR, more than IDZ, reduced the time spent in the TR-paired compartment, but without statistical significance. AG reversed the TR-induced CPP, while EFR and IDZ only decreased the time spent in the TR-paired compartment, without statistical significance.

Effects of imidazoline agents in a rat conditioned place preference model of addiction

Abstract: Agmatine (AG), idazoxan (IDZ), and efaroxan (EFR) are imidazoline receptor ligands with beneficial effects in central nervous system disorders. The present study aimed to evaluate the interaction between AG, IDZ, and EFR with an opiate, tramadol (TR), in a conditioned place preference (CPP) paradigm. In the experiment, we used five groups with 8 adult male Wistar rats each. During the condition session, on days 2, 4, 6, and 8, the rats received the drugs (saline, or TR, or IDZ and TR, or EFR and TR, or AG and TR) and were placed in their least preferred compartment. On days 1, 3, 5, and 7, the rats received saline in the preferred compartment. In the preconditioning, the preferred compartment was determined. In the postconditioning, the preference for one of the compartments was reevaluated. TR increased the time spent in the non-preferred compartment. AG decreased time spent in the TR-paired compartment. EFR, more than IDZ, reduced the time spent in the TR-paired compartment, but without statistical significance. AG reversed the TR-induced CPP, while EFR and IDZ only decreased the time spent in the TR-paired compartment, without statistical significance.

Is there a rendezvous for SARS-CoV-2 and Agmatine?

Abstract: The catastrophe of the ongoing COVID-19 pandemic is caused by Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2). The respiratory system appears to be ground zero in the majority of the patients. However, many other organs can get infected by cytokines, chemokines and other mediators released in response to the presence of the virus. The neurotropism by the SARS-CoV-2 is established beyond doubt. In addition to non-specific symptoms, the symptoms specific to central and/or peripheral nervous system diseases as well as neuromuscular diseases have been observed in numerous clinical cases. These observations and the experiences with other coronavirus infections earlier and flu pandemics raise concerns not only about the neurological effects in active disease but also about the long-term effects generated by the infection, immune and inflammatory functions. The knowledge of biological actions of agmatine in the backdrop of physiological events instigated by invading SARS-CoV-2 and host’s response, especially in neural events, focuses on the possible overlaps of biomolecular pathways at a number of instances. This is not surprising since the factors stimulated during SARS-CoV-2 infection are the disease-generating neuroinflammatory components altered by agmatine. Hence, we hypothesize the possible beneficial role of agmatine in SARS-CoV-2 infection. Based on a narrative review of the literature, agmatine can be proposed as a plausible beneficial candidate for supporting treatment of SARS-CoV-2 infection and for addressing post-infection neurological complications.

Agmatine alleviates cisplatin-induced ototoxicity by activating PI3K/AKT signaling pathway

Abstract: Cisplatin-induced ototoxicity can be partially attributed to excessive reactive oxygen species (ROS) production, and agmatine is well-known for the activation of the phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT) pathway to inhibit ROS production. Whether agmatine could be used to alleviate cisplatin-induced ototoxicity is investigated. Cisplatin-exposed House Ear Institute-Organ of Corti 1 (HEI-OC1) cells and cochlear explants showed increased ROS production detected by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining and decreased cell viability detected by Cell Counting Kit-8 (CCK-8) or Myosin 7a staining, which could be reversed by the agmatine pretreatment. Cisplatin intraperitoneally injected C57BL/6 mice demonstrated damaged auditory function as indicated by distortion products otoacoustic emissions (DPOAEs) and auditory brainstem response (ABR) assays, and trans-tympanically administrated agmatine in the left ears could partly prevent the auditory function loss. Mechanistically, downregulated B-cell lymphoma 2 (Bcl-2) expression, upregulated Bcl2-associated x (Bax) expression, and diminished p-PI3K and p-AKT expression were detected in cisplatin-exposed HEI-OC1 cells and cochlear explants, which could be prevented by the pretreatment with agmatine. Our investigation demonstrates that agmatine pretreatment could alleviate cisplatin-induced ototoxicity with the activation of PI3K/AKT signaling pathway.

New Insights into the Determinants of Specificity in Human Type I Arginase: Generation of a Mutant That Is Only Active with Agmatine as Substrate

Abstract: Arginase catalyzes the hydrolysis of L-arginine into L-ornithine and urea. This enzyme has several analogies with agmatinase, which catalyzes the hydrolysis of agmatine into putrescine and urea. However, this contrasts with the highlighted specificity that each one presents for their respective substrate. A comparison of available crystal structures for arginases reveals an important difference in the extension of two loops located in the entrance of the active site. The first, denominated loop A (I129-L140) contains the residues that interact with the alpha carboxyl group or arginine of arginase, and the loop B (D181-P184) contains the residues that interact with the alpha amino group of arginine. In this work, to determine the importance of these loops in the specificity of arginase, single, double, and triple arginase mutants in these loops were constructed, as well as chimeras between type I human arginase and E. coli agmatinase. In previous studies, the substitution of N130D in arginase (in loop A) generated a species capable of hydrolyzing arginine and agmatine. Now, the specificity of arginase is completely altered, generating a chimeric species that is only active with agmatine as a substrate, by substituting I129T, N130Y, and T131A together with the elimination of residues P132, L133, and T134. In addition, Quantum Mechanic/Molecular Mechanic (QM/MM) calculations were carried out to study the accommodation of the substrates in in the active site of this chimera. With these results it is concluded that this loop is decisive to discriminate the type of substrate susceptible to be hydrolyzed by arginase. Evidence was also obtained to define the loop B as a structural determinant for substrate affinity. Concretely, the double mutation D181T and V182E generate an enzyme with an essentially unaltered kcat value, but with a significantly increased Km value for arginine and a significant decrease in affinity for its product ornithine.

Bioactive amines in ingredients and feeds of broilers and storage effects on their levels

Abstract: To quantify amines in ingredients and in different types of feed and to verify spermine inclusion influence in polyamine levels at storage of experimental diets of broiler, ingredients to formulate diets and commercial starting and growth feeds and were purchased. Spermidine, spermine, putrescine, cadaverine, agmatine, tyramine and histamine were detected by ion pair high performance liquid chromatography in ingredients, commercial diets, control and 0.06 and 012% spermine included formulations. Bioactive amines levels were analysed weekly to initial and growth diets, respectively until 21st and 49th days of storage at 26 ± 3°C and 72% relative humidity. All amines were detected in commercial feed. Spermidine and spermine predominate in soybean, wheat and corn, and tyramine in meat and bone meal. To initial diets averages of cadaverine reduced significantly in day 21, except for 0.06% spermine inclusion; agmatine decreased (p<0.05) in times, except for 0.12% spermine inclusion; spermidine were smaller (p<0.05) at 14 and 21 days and increased significantly with the level of inclusion. In growth diets cadaverine oscillated (p<0.05) between 0.35 at 28 days in control and 1.15 mg.100g-1 in 0.06% spermine inclusion at 49 days. Agmatine were 0.36 to 0.91 mg.100g-1 in control; spermidine vary significantly at 7 days in control and in 0.12% spermine inclusion at 28 days; spermine vary from 1.33 at 42 days to control to 72.55 mg.100g-1 at 7 days in 0.12% spermine inclusion. Polyamine levels were low in ingredients, commercial feed and initial and growth experimental formulations even when stored for 21 or 49 days.

Compartmentation of Putrescine Synthesis in Plants

Abstract: Three plant pathways for the synthesis of putrescine have been described to date. These are the synthesis of putrescine from ornithine, by ornithine decarboxylase (ODC); and the synthesis of putrescine from arginine by arginine decarboxylase, agmatine iminohydrolase (AIH) and N-carbamoylputrescine amidohydrolase (NLP1); or arginine decarboxylase and agmatinase. Several enzymes associated with putrescine synthesis have yet to be localized. Here we showed that ODC in soybeans and rice was localized to the ER. In rice, agmatinase is localized to the mitochondria. In A. thaliana there are five isoforms of AIH and three isoforms of NLP1. Stable GFP-tagged transformants of the longest isoforms of AIH and NLP1 showed that both proteins were localized to the ER in leaves and roots of A. thaliana. Four of the isoforms of AIH and all of the isoforms of NLP1 were localized to the ER. However, AIH1.4 was localized to both the ER and the chloroplast. Combining these results with other published data, reveal that putrescine synthesis is excluded from the cytoplasm and is spatially localized to the chloroplast, ER and likely the mitochondria. Synthesis of putrescine in the ER may facilitate cell to cell transport via plasmodesmata, or secretion via vesicles. Differential expression of these pathways may enable putrescine-mediated activation of hormone-responsive genes.

Agmatine Administration Effects on Equine Gastric Ulceration and Lameness

Abstract: Osteoarthritis (OA) accounts for up to 60% of equine lameness. Agmatine, a decarboxylated arginine, may be a viable option for OA management, based on reports of its analgesic properties. Six adult thoroughbred horses, with lameness attributable to thoracic limb OA, received either daily oral phenylbutazone (6.6 mg/kg), agmatine sulfate (25 mg/kg) or a control for 30 days, with 21-day washout periods between treatments. Subjective lameness, thoracic limb ground reaction forces (GRF), plasma agmatine and agmatine metabolite levels were evaluated using an established rubric, a force platform, and mass spectrometry, respectively, before, during and after each treatment period. Gastric ulceration and plasma chemistries were evaluated before and after treatments. Braking GRFs were greater after 14 and 29 days of agmatine compared to phenylbutazone administration. After 14 days of phenylbutazone administration, vertical GRFs were greater than for agmatine or the control. Glandular mucosal ulcer scores were lower after agmatine than phenylbutazone administration. Agmatine plasma levels peaked between 30 and 60 min and were largely undetectable by 24 h after oral administration. In contrast, plasma citric acid levels increased throughout agmatine administration, representing a shift in the metabolomic profile. Agmatine may be a viable option to improve thoracic limb GRFs while reducing the risk of glandular gastric ulceration in horses with OA.

Protective Effect of Agmatine Against Cisplatin- Induced Cellular Apoptosis in an Auditory Cell Line.

Abstract: BACKGROUND The aims of this study were to evaluate the protective effects of agmatine against cisplatin-induced cellular apoptosis in an audi- tory cell line and to prove the protective mechanism of agmatine. METHODS The House Ear Institute-Organ of Corti 1 cells were co-treated with agmatine at different concentrations and 15 μM of cisplatin for 48 hours. Cell viability and proliferation were measured. Annexin V-fluorescein isothiocyanate /propidium iodide staining was performed to analyze apoptosis. The levels of intracellular reactive oxygen species were measured using flow cytometry. The expression of BCL2-associated X protein and the enzymatic activity of caspase-3 was measured to examine the pathway of apoptosis induction. RESULTS In normal conditions, the maximal protective effect occurred with 10 mM of agmatine. However, in the presence of cisplatin, the maximal protective effect was observed from 8 mM of agmatine. Thus, 8 mM was chosen as the ideal agmatine concentration for the analysis of protective effects against cisplatin-induced cytotoxicity. Agmatine exerted a significant protective effect against 15 μM of cisplatin when applied for 48 hours and reduced the proportion of necrotic and late apoptotic cells. Agmatine did not significantly reduce the cisplatin-induced increase in reactive oxygen species but decreased the expression of BCL2-associated X protein and the activity of caspase-3. CONCLUSION Agmatine protected against cisplatin-induced cellular apoptosis in an auditory cell line. These effects were mediated by the pro- tection of mitochondrial function and inhibition of apoptosis.

Farelerde Pentilenetetrazol ile İndüklenen Epilepsi Modelinde Agmatinin Etkilerinin ve Nitrik Oksitin Katkısının Araştırılması

Abstract: Objective: Agmatine is an endogenous cationic amin and have been reported several neurotherapeutic effects through α2-adrenoceptors, imidazoline binding sites, inhibition of NMDA receptors and nitric oxide (NO) synthase. NO was reported to act as a neuromodulator and neurotransmitter in central nervous system and has proconvulsant/anticonvulsant activities in convulsion models. We aimed to compare the anticonvulsant activities of agmatine, sodium valproate, gabapentin and phenytoin, and to investigate the role of NO in effects of drugs. Material and Methods: Epilepsy seizures were induced in swiss-albino mice by single dose injection of penthylenetetrazole (PTZ) (60 mg/kg). Myoclonic-jerk (MJ) and generalized tonic-clonic seizures (GTCS) of mice were recorded. Agmatine (10 mg/kg), sodium valproate (150 mg/kg), gabapentin (20 mg/kg) and phenytoin (20 mg/kg) alone or in combinations with N(G)-Nitro-L-arginine-methyl-ester (L-NAME, 5 mg/kg), the precursor of NO, L-arginine (L-Arg, 60 mg/kg) and non-specific NO synthase inhibitor, were injected intraperitoneally. Results: While agmatine and sodium valproate significantly prevented GTCS%, phenytoin and gabapentin did not prevent. L-Arg significantly reduced activity of agmatine on MJ%. Both L-Arg and L-NAME did not affect activity of phenytoin on MJ% and GTCS%. L-Arg did not change the activity of gabapentin on MJ% and GTCS%. L-NAME significantly increased activity of gabapentin on MJ% and GTCS%. Conclusion: This study suggested that NO may have a role on anticonvulsant activity of agmatine and gabapentin but not those of sodium valproate and phenytoin.

Effects of polyamine synthesis enzymes on angiogenesis and apoptosis during endometriosis

Abstract: Objectives: Since we assumed that endometriosis is a benign cell division disorder, our study was conducted to investigate the effects of the relationships between polyamine synthesis and angiogenesis in the formation of endometriosis. Material and methods: Thirty-five patients with endometriosis and 35 healthy female women were included in the study. The patient and the control groups were compared regarding the blood levels of agmatine, argininecarboxylase (ADC), ornithinecarboxylase (ODC), agmatinase, arginase, ornithine, and the vascular endothelial growth factor (VEGF). Results : There is a statistically significant difference between the patient and the control groups regarding the agmatinase, arginase and VEGF levels (higher in the patient group) (p < 0.05). There is no statistically significant difference between the patient and the control groups regarding the ODC, ornithine and the ADC levels (p > 0.05). There is a statistically significant difference between the patient and the control groups regarding the agmatine levels (higher in the control group) (p < 0.05). Conclusions: The increase in the serum levels of polyamine synthesis enzymes may contribute to the formation of endometriosis. It is anticipated that the study of the relationship between enzymes and molecules in the polyamine synthesis pathway and angiogenesis in patients with endometriosis will contribute to the literature.

NMDA Receptor Neuropharmacology: NMDA Receptor‐mediated Calcium Transients are Attenuated by Agmatine in Mouse Spinal Cord Dorsal Horn

Abstract: NMDA receptor (NMDAr) plays an important role in synaptic plasticity and one of the targets for chronic pain management is antagonism of the NMDA receptors (NMDAr). Agmatine is an endogenous aminoguanidine that preferentially antagonizes GluN2B‐containing NMDArs. Our previous studies showed that the intrathecal administration of agmatine, an endogenous aminoguanidine that selectively antagonizes GluN2B‐containing NMDArs, reverses the mechanical hypersensitivity without motor side effects. In this study, we demonstrated the spinal modulatory effect of agmatine and other NMDAr antagonists utilizing calcium imaging.