ArticleLiterature Review

L-Glycine: a novel antiinflammatory, immunomodulatory, and cytoprotective agent

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Abstract

In recent years, evidence has mounted in favor of the antiinflammatory, immunomodulatory and cytoprotective effects of the simplest amino acid L-glycine. This article will focus on the recent findings about the responsible mechanisms of protection and review the beneficial effects of glycine in different disease states. Glycine protects against shock caused by hemorrhage, endotoxin and sepsis, prevents ischemia/reperfusion and cold storage/reperfusion injury to a variety of tissues and organs including liver, kidney, heart, intestine and skeletal muscle, and diminishes liver and renal injury caused by hepatic and renal toxicants and drugs. Glycine also protects against peptidoglycan polysaccharide-induced arthritis and inhibits gastric secretion and protects the gastric mucosa against chemically and stress-induced ulcers. Glycine appears to exert several protective effects, including antiinflammatory, immunomodulatory and direct cytoprotective actions. Glycine acts on inflammatory cells such as macrophages to suppress activation of transcription factors and the formation of free radicals and inflammatory cytokines. In the plasma membrane, glycine appears to activate a chloride channel that stabilizes or hyperpolarizes the plasma membrane potential. As a consequence, agonist-induced opening of L-type voltage-dependent calcium channels and the resulting increases in intracellular calcium ions are suppressed, which may account for the immunomodulatory and antiinflammatory effects of glycine. Lastly, glycine blocks the opening of relatively non-specific pores in the plasma membrane that occurs as the penultimate event leading to necrotic cell death. Multiple protective effects make glycine a promising treatment strategy for inflammatory diseases.

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... Recent studies reported of the critical roles of glycine (Gly) as anti-inflammatory, immunomodulatory and cytoprotective agents [1]. It has been experimentally shown that glycine could help treat many diseases like ischemia-reperfusion injury [2][3][4], hepatic fibrosis [5], shock [6][7][8][9], arthritis [10], transplantation [11][12][13], tumor [14][15][16][17][18], alcoholic hepatitis [19] and drug toxicity [20,21]. ...
... Dietary glycine has also shown critical roles in cancer treatment by inhibiting cell proliferation via WY-14, 643 known as a peroxisomal proliferator [18]. It probably blocks the activation of kB cells and inhibits tumor growth of the implanted B16 melanoma cells where all these results indicate a general anticancer characteristic of glycine [1,18]. ...
... Furthermore, glycine treatment of subjects with monocytes helps reduce the generation of proinflammatory cytokines like tumor necrosis factor (TNF-α) and enhances the generation of anti-inflammatory cytokine IL-10 showing the anti-inflammatory property of glycine [1,22]. Ikejima et al. indicated TNF-α production in cultured Kupffer cells due to a significant decrease of lipopolysaccharide (LPS) by glycine [59]. ...
Article
The adsorption behavior of the amino acid, glycine (Gly), via the carboxyl, hydroxyl, and amino groups onto the surfaces of Al12N12 and Al16N16 fullerene-like cages were computationally evaluated by the combination of density functional theory (DFT) and molecular docking studies. It was found that Gly can chemically bond with the Al12N12 and Al16N16 fullerene-like cages as its amino group being more favorable to interact with the aluminum atoms of the adsorbents compared to carboxyl and hydroxyl groups. Oxygen and carbon doping were reported to reduce steric hindrance for Glycine interaction at Al site of Al12ON11/Gly and Al12CN11/Gly complexes. Interaction was further enhanced by oxygen doping due to its greater electron withdrawing effect. Herein, the Al12ON11/Gly complex where two carbonyl groups of Gly are bonded to the aluminum atoms of the Al12N12 fullerene-like cage is the most stable interaction configuration showing ΔadsH and ΔadsGvalues of -81.74 kcal/mol and -66.21 kcal/mol, respectively. Computational studies also revealed the frequency shifts that occurred due to the interaction process. Molecular docking analysis revealed that the Al12N12/Gly (-11.7 kcal/mol) and the Al12ON11/Gly (-9.2 kcal/mol) complexes have a good binding affinity with protein tumor necrosis factor alpha (TNF-α). TNF-α was implicated as a key cytokine in various diseases, and it has been a validated therapeutic target for the treatment of rheumatoid arthritis. These results suggest that the Al12N12/Gly complex in comparison with the Al16N16/Gly, Al12ON11/Gly, and the Al12CN11/Gly complexes could be efficient inhibitors of TNF-α.
... Glycine is a non-essential amino acid and is often considered biologically neutral. However, studies have shown that Lglycine has effective anti-inflammatory, immunomodulatory and cytoprotective properties (45). The underlying mechanisms responsible for the protective effects of glycine are not completely clear, but may include suppression of calcium signaling, inhibition of inflammatory cell activation and decreased formation of free radicals and other toxic compounds (45). ...
... However, studies have shown that Lglycine has effective anti-inflammatory, immunomodulatory and cytoprotective properties (45). The underlying mechanisms responsible for the protective effects of glycine are not completely clear, but may include suppression of calcium signaling, inhibition of inflammatory cell activation and decreased formation of free radicals and other toxic compounds (45). In addition, dietary glycine was also reported to inhibit the growth of certain types of tumors, such as liver tumors (46) and melanoma tumors (47). ...
Article
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Cancer cachexia is a complex metabolic syndrome characterized by involuntary skeletal muscle loss and is associated with poor clinical outcome, decreased survival and negatively influences cancer therapy. No curative treatments are available for cancer cachexia, but nutritional intervention is recommended as a cornerstone of multimodal therapy. Optimal nutritional care is pivotal in the treatment of cancer cachexia, and the effects of nutrients may extend beyond provision of adequate energy uptake, targeting different mechanisms or metabolic pathways that are affected or deregulated by cachexia. The evidence to support this notion derived from nutritional intervention studies in experimental models of cancer cachexia is systematically discussed in this review. Moreover, experimental variables and readout parameters to determine skeletal muscle wasting and cachexia are methodologically evaluated to allow critical comparison of similar studies. Single- and multinutrient intervention studies including qualitative modulation of dietary protein, dietary fat, and supplementation with specific nutrients, such as carnitine and creatine, were reviewed for their efficacy to counteract muscle mass loss and its underlying mechanisms in experimental cancer cachexia. Numerous studies showed favorable effects on impaired protein turnover and related metabolic abnormalities of nutritional supplementation in parallel with a beneficial impact on cancer-induced muscle wasting. The combination of high quality nutrients in a multitargeted, multinutrient approach appears specifically promising, preferentially as a multimodal intervention, although more studies investigating the optimal quantity and combination of nutrients are needed. During the review process, a wide variation in timing, duration, dosing, and route of supplementation, as well as a wide variation in animal models were observed. Better standardization in dietary design, and the development of experimental models that better recapitulate the etiology of human cachexia, will further facilitate successful translation of experimentally-based multinutrient, multimodal interventions into clinical practice.
... Glycine has been shown to attenuate inflammatory response [18], and has a cytoprotective property [19]. This metabolite was increased in patients with sepsis [10]. ...
... Despite its promising benefits, limited clinical study is available. Therefore, its protective mechanism and safety dose remain to be elucidated [19]. ...
Article
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A disruption of several metabolic pathways in critically ill patients with sepsis indicates that metabolomics might be used as a more precise tool for sepsis and septic shock when compared with the conventional biomarkers. This article provides information regarding metabolomics studies in sepsis and septic shock patients. It has been shown that a variety of metabolomic pathways are altered in sepsis and septic shock, including amino acid metabolism, fatty acid oxidation, phospholipid metabolism, glycolysis, and tricarboxylic acid cycle. Based upon this comprehensive review, here, we demonstrate that metabolomics is about to change the world of sepsis biomarkers, not only for its utilization in sepsis diagnosis, but also for prognosticating and monitoring the therapeutic response. Additionally, the future direction regarding the establishment of studies integrating metabolomics with other molecular modalities and studies identifying the relationships between metabolomic profiles and clinical characteristics to address clinical application are discussed in this article. All of the information from this review indicates the important impact of metabolomics as a tool for diagnosis, monitoring therapeutic response, and prognostic assessment of sepsis and septic shock. These findings also encourage further clinical investigations to warrant its use in routine clinical settings.
... Glycine is a substrate for the production of glutathione, heme and creatine and, therefore, plays a role in overall antioxidant defence and metabolism. Glycine administration also modulates homeostasis by activating glycine-gated chloride channels in inflammatory cells, thereby effectively reducing [Ca 2+ ] i cytokine production, and whole-body (systemic) inflammation in several models (Zhong et al. 2003). Because inflammation plays a key role in the aetiology of many muscle-wasting conditions, we have tested the hypothesis that glycine supplementation represents a simple, safe and promising nutritional intervention for tackling skeletalmuscle wasting in many diseases and conditions. ...
Article
Nature’s paradox in skeletal muscle describes the seemingly mutually exclusive relationship between muscle fibre size and oxidative capacity. In mammals, there is a constraint on the size at which mitochondria-rich, high O2-dependent oxidative fibres can attain before they become anoxic or adapt to a glycolytic phenotype, being less reliant on O2. This implies that a muscle fibre can hypertrophy at the expense of its endurance capacity. Adaptations to activity (exercise) generally obey this relationship, with optimal muscle endurance generally being linked to an enhanced proportion of small, slow oxidative fibres and muscle strength (force and/or power) being linked to an enhanced proportion of large, fast glycolytic fibres. This relationship generally constrains not only the physiological limits of performance (e.g. speed and endurance), but also the capacity to manipulate muscle attributes such as fibre size and composition, with important relevance to the livestock and aquaculture industries for producing specific muscle traits such as (flesh) quality, texture and taste. Highly glycolytic (white) muscles have different traits than do highly oxidative (red) muscles and so the ability to manipulate muscle attributes to produce flesh with specific traits has important implications for optimising meat production and quality. Understanding the biological regulation of muscle size, and phenotype and the capacity to manipulate signalling pathways to produce specific attributes, has important implications for promoting ethically sustainable and profitable commercial livestock and aquaculture practices and for developing alternative food sources, including ‘laboratory meat’ or ‘clean meat’. This review describes the exciting potential of manipulating muscle attributes relevant to animal production, through traditional nutritional and pharmacological approaches and through viral-mediated strategies that could theoretically push the limits of muscle fibre growth, adaptation and plasticity.
... Serine acts as a key substance in purine biosynthesis and one-carbon metabolic cycles, and alleviates oxidative stress via supporting glutathione synthesis and methionine cycle (Zhou et al., 2017). Glycine is a cytoprotective agent that scavenges intracellular ROS, inhibits increased intracellular calcium and stabilizes the plasma membrane (Zhong et al., 2003). Glycine, serine and threonine metabolism has been known as biomarker pathway in amphibians after exposure ATR (Snyder et al., 2017). ...
Article
The widespread use of the herbicides Atrazine (ATR) has been raised attention due to its ubiquitous occurrence in the environment. As an endocrine disruptor, ATR causes reproductive, immune, nervous system toxicity in biota. In this study, we aimed to investigate metabolic profile characteristics and potential metabolic biomarker that reflects specific damage in toxic effect after ATR exposure. Hence, a metabolomics study was performed to determine the significantly affected metabolites and the reproduction and locomotion of C. elegans were investigated. Mediation analysis was used to evaluate the mediating effect of metabolites on association between ATR exposure and toxic effect. ATR (≥0.04 mg/L) caused the significant dose dependent reduction of brood size and locomotion behavior, however, the body length and width were significantly decreased only in 40 mg/L group. These results suggesting that brood size, head thrashes and body bends are more sensitive indictor to assessment ATR toxicity in C. elegans. Meanwhile, metabolomics analysis revealed that ATR exposure can induce metabolic profiles significant alterations in C. elegans. We found that 9 metabolites significantly increased and 18 metabolites significantly decreased, such as phosphatidylcholine, GMP, CDP-choline, neopterin etc. Those alteration of metabolites were mainly involved in the pathways: glycerophospholipid metabolism, glycolysis/gluconeogenesis, folate biosynthesis, glycine, serine and threoninemetabolism, pyrimidine and purine metabolism. Overall, these changes are signs of possible oxidative stress and ATP synthesis disruption modification. Mediation analysis showed a significant indirect effect of ATR exposure on brood size, via 7,8-dihydroneopterin 2′,3′-cyclic-p, and phosphatidylcholine might mediate association between ATR exposure and body bends, suggesting that 7,8-dihydroneopterin 2′,3′-cyclic-p and phosphatidylcholine might be potentially specificity marker for brood size and body bend respectively. This preliminary analysis investigates metabolic characteristics in C. elegans after ATR exposure, helping to understand the pathways involved in the response to ATR exposure and provide potential biomarkers for the safety evaluation of ATR.
... It also binds to glycine receptors in adult CNS for inhabitant post-synaptic neurons (Zhao et al. 2018). Previous researchers have documented neuroprotective effects of glycine in anoxia, ischemic reperfusion, hypoxia and reactive oxygen species (ROS) (Liu et al. 2007;Yang et al. 2000;Zhong et al. 2003). In addition to that, glycine is a major nonessential amino acid that has several roles in human immunity, metabolism, survival, development, and cytoprotection systems (Lu et al. 2017). ...
Article
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Phononic crystals (PnCs) provide an innovative platform for sensing biomaterials. In this work, we introduce a defective 1D-PnC from lead-epoxy multilayer with a central defect layer filled with glycine. The transmission spectra of the incident acoustic wave are calculated numerically by the transfer matrix method. The working principle of this sensor is to sense how much change occurs in the concentration of glycine. Any change in glycine concentration affects the acoustic properties of glycine directly. Thereby the central resonance frequency in the transmission spectrum shifted. In this study, we firstly made optimization for the type of the structure (symmetric/asymmetric), the number of periods, the glycine layer thickness, and glycine concentration to get the best sensor performance. The proposed sensor provided high sensitivity (S = 969.973 kHz) over just a molar ratio range 0–0.383 mol/L. Moreover, we calculated other performance parameters such as the quality factor, which reached a maximum value of 13,497, sensor resolution of 3.49 × 105 Hz, and figure of merit of 4.2. Based on the obtained results, this sensor has many merits such as it is designed from low cost materials, the ease of fabrication, high sensitivity, and absence of any electronic component in its design.
... The reason for that may not be fully understood yet. Nevertheless, one may speculate that the repeated application of glycine powder may to some extent induce an anti-inflammatory and cytoprotective effect (Tsang et al., 2018;Zhong et al., 2003). ...
Article
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Aim: Glycine powder air polishing (GPAP) procedure has become popular. Aim of the analysis was to compare the clinical outcomes during supportive periodontal therapy (SPT) of subgingival application of GPAP with those using sole conventional mechanical debridement (SC). Material and methods: Over a median SPT period of 5.3 years (re-evaluation through last observation), the GPAP-cohort (n=263) received supra-and subgingival biofilm removal with GPAP. Supragingival calculus was removed using curets and sonic scalers here. Patients in the SC-cohort (n=264) were treated with sonic scalers, curets and rubber cup polishing only. Changes in i.e. pocket probing depth (PPD) and furcation involvement were assessed retrospectively. A bootstrapping equivalence testing method in line with the principle of the two one-sided tests (TOST) procedure was used to compare clinical outcomes. Results: The GPAP procedure was statistically equivalent to SC regarding the number of sites with stable PPDs (83.3%; IQR 68.8%, 91.0% vs. 84.0%; IQR 77.8%, 90.0%). However, in the GPAP-cohort, a trend towards deterioration in furcation status (no equivalence) was noted. Conclusions: In periodontal maintenance, the use of GPAP instead of mechanical plaque removal does not improve the clinical outcome. It seems to be contraindicated to treat furcation defects with GPAP only. Keywords: equivalence test; low abrasive air polishing; supportive periodontal therapy.
... Glycine is often considered biologically neutral and has even been used as an isonitrogenous control in amino acid supplementation studies. However, glycine is an anti-inflammatory amino acid which effectively blocks inflammatory cell activation 17 . Increased circulating glycine concentrations activate glycine-gated Cl − channels in inflammatory cells, such as macrophages 18 , and thereby blunt pro-inflammatory cytokine production 19 . ...
Article
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Duchenne muscular dystrophy (DMD) is an X-linked genetic disease characterized by progressive muscle wasting and weakness and premature death. Glucocorticoids (e.g. prednisolone) remain the only drugs with a favorable impact on DMD patients, but not without side effects. We have demonstrated that glycine preserves muscle in various wasting models. Since glycine effectively suppresses the activity of pro-inflammatory macrophages, we investigated the potential of glycine treatment to ameliorate the dystrophic pathology. Dystrophic mdx and dystrophin-utrophin null (dko) mice were treated with glycine or L-alanine (amino acid control) for up to 15 weeks and voluntary running distance (a quality of life marker and strong correlate of lifespan in dko mice) and muscle morphology were assessed. Glycine increased voluntary running distance in mdx mice by 90% (P < 0.05) after 2 weeks and by 60% (P < 0.01) in dko mice co-treated with prednisolone over an 8 week treatment period. Glycine treatment attenuated fibrotic deposition in the diaphragm by 28% (P < 0.05) after 10 weeks in mdx mice and by 22% (P < 0.02) after 14 weeks in dko mice. Glycine treatment augmented the prednisolone-induced reduction in fibrosis in diaphragm muscles of dko mice (23%, P < 0.05) after 8 weeks. Our findings provide strong evidence that glycine supplementation may be a safe, simple and effective adjuvant for improving the efficacy of prednisolone treatment and improving the quality of life for DMD patients.
... Gly exerts protective effects, including immunomodulatory, anti-inflammatory, and direct cytoprotective actions. Gly suppresses free radical formation, transcription factor activation, and inflammatory cytokines by acting on inflammatory cells such as macrophages (243). In a rat model, it was found that intraperitoneal administration of Gly (0.5 mg/g body weight) reduces cardiac ischemia/reperfusion injury and myocardial apoptosis, with the ischemic area significantly decreased (244). ...
Article
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Cardiovascular disease is the leading global health concern and responsible for more deaths worldwide than any other type of disorder. Atherosclerosis is a chronic inflammatory disease in the arterial wall, which underpins several types of cardiovascular disease. It has emerged that a strong relationship exists between alterations in amino acid (AA) metabolism and the development of atherosclerosis. Recent studies have reported positive correlations between levels of branched-chain amino acids (BCAAs) such as leucine, valine, and isoleucine in plasma and the occurrence of metabolic disturbances. Elevated serum levels of BCAAs indicate a high cardiometabolic risk. Thus, BCAAs may also impact atherosclerosis prevention and offer a novel therapeutic strategy for specific individuals at risk of coronary events. The metabolism of AAs, such as L-arginine, homoarginine, and L-tryptophan, is recognized as a critical regulator of vascular homeostasis. Dietary intake of homoarginine, taurine, and glycine can improve atherosclerosis by endothelium remodeling. Available data also suggest that the regulation of AA metabolism by indoleamine 2,3-dioxygenase (IDO) and arginases 1 and 2 are mediated through various immunological signals and that immunosuppressive AA metabolizing enzymes are promising therapeutic targets against atherosclerosis. Further clinical studies and basic studies that make use of animal models are required. Here we review recent data examining links between AA metabolism and the development of atherosclerosis.
... Glycine directly scavenges radicals (Fang et al. 2002) and can be used to produce glutathione, a strong antioxidant (Hall 1998). Glycine mediates its immunomodulatory effects through its glycine receptor (glycine-gated chloride channels), with which it controls intracellular Ca 2+ concentration, and suppresses activation of transcription factors, with consequent regulation of inflammatory cytokine and ROS production (Wang et al. 2013;Zhong et al. 2003). Accumulation of proline may be indicative of poly (I:C)-induced collagen degradation, to facilitate proline-based electron production to generate adenosine triphosphate (ATP) for survival under stressful conditions (Phang et al. 2010). ...
Article
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Poly (I:C) is a viral pathogen-associated molecular pattern (PAMP) and a synthetic dsRNA analogue, which orchestrates antiviral responses through well conserved toll-like receptor 3 (tlr3), retinoic acid inducible gene I (RIG-1) like receptors (RLRs) and class A scavenger receptors (SR-As). This study investigated the effect of poly (I:C) in vivo on Chinook salmon (Oncorhynchus tshawytscha) haematology, innate immunity, serum and liver metabolite profiles, and lymphoid tissue cytokine transcript expression, over a 5-day period post-exposure. Poly (I:C) significantly enhanced differential mono-cyte and neutrophil counts, and reactive oxygen species (ROS) production in peripheral blood mononuclear cells (PBMCs). GC-MS-based metabolomics revealed that poly (I:C) significantly altered 23 liver and 13 serum metabolic features. Liver and serum metab-olites involved in branched chain amino acid (BCAA) metabolism significantly increased at day 1 and returned to baseline by day 5; the citric acid cycle and ROS regulation were altered. Also, liver and serum metabolites involved in glycolysis were persistently depleted from day 1 to day 5. Liver metabolites involved in phospholipid metabolism increased at day 4 to 5 and decreased from day 2 to 4 in serum. At the molecular level, poly (I:C) upregulated antiviral ifnγ and Mx1, and anti-inflammatory il-10 in fish lymphoid tissues, which normalised to baseline by day 5. Overall, poly (I:C) induced innate and adaptive immune responses through multiple mechanisms and different levels in teleost O. tshawytscha. Findings may aid design and development of amelioration strategies against viral pathogens via metabolome reprograming. Targeted studies are recommended into identified pathways and survival biomarkers.
... Glycine is a simple amino acid with known biological activity. Experimental studies show that glycine reduces human and rat platelet aggregation in vitro [16], improves microcirculation [17], has antioxidative effects [18,19] as well as anti-inflammatory, immunomodulatory, and direct cytoprotective properties [20]. Moreover, glycine was shown to have anti-tumorigenic properties in a previously described animal model of CRLM induced by CC531 cells [21]. ...
Article
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Introduction: FOLFOX chemotherapy (CTx) is used for the treatment of colorectal liver metastasis (CRLM). Side effects include rare cardiotoxicity, which may limit the application of FOLFOX. Currently, there is no effective strategy to prevent FOLFOX-induced cardiotoxicity. Glycine has been shown to protect livers from CTx-induced injury and oxidative stress, and it reduces platelet aggregation and improves microperfusion. This study tested the hypothesis of glycine being cardioprotective in a rat model of FOLFOX in combination with CRLM. Materials and methods: The effect of glycine was tested in vitro on human cardiac myocytes (HCMs). To test glycine in vivo Wag/Rij rats with induced CRLM were treated with FOLFOX ±5% dietary glycine. Left ventricle ejection fraction (LVEF), myocardial fibrosis, and apoptosis, also heart fatty acid binding protein (h-FABP) and brain natriuretic peptide levels were monitored. PCR analysis for Collagen type I, II, and brain natriuretic peptide (BNP) in the heart muscle was performed. Results: In vitro glycine had no effect on HCM cell viability. Treatment with FOLFOX resulted in a significant increase of h-FABP levels, increased myocardial fibrosis, and apoptosis as well as increased expression of type I Collagen. Furthermore, FOLFOX caused a decrease of LVEF by 10% (p = 0.028). Dietary glycine prevented FOLFOX-induced myocardial injury by preserving the LVEF and reducing the levels of fibrosis (p = 0.012) and apoptosis (p = 0.015) in vivo. Conclusions: Data presented here demonstrate for the first time that dietary glycine protects the heart against FOLFOX-induced injury during treatment for CRLM.
... In both rodent studies, glycine administration was also associated with weight loss, but only in females. Glycine has also been reported to have anticancer and antiinflammatory effects in rodents [336][337][338] . In limited human clinical studies, glycine supplementation may have been protective in the context of metabolic diseases 337,339 , although larger studies are needed. ...
Article
Although death is inevitable, individuals have long sought to alter the course of the ageing process. Indeed, ageing has proved to be modifiable; by intervening in biological systems, such as nutrient sensing, cellular senescence, the systemic environment and the gut microbiome, phenotypes of ageing can be slowed sufficiently to mitigate age-related functional decline. These interventions can also delay the onset of many disabling, chronic diseases, including cancer, cardiovascular disease and neurodegeneration, in animal models. Here, we examine the most promising interventions to slow ageing and group them into two tiers based on the robustness of the preclinical, and some clinical, results, in which the top tier includes rapamycin, senolytics, metformin, acarbose, spermidine, NAD⁺ enhancers and lithium. We then focus on the potential of the interventions and the feasibility of conducting clinical trials with these agents, with the overall aim of maintaining health for longer before the end of life.
... Glycine, a common non-essential amino acid, in addition to its role in protein biosynthesis is the participant of numerous metabolic pathways including purine, creatine, heme and glutathione biosynthesis 41 . Thus, the depletion of glycine could be the cause of several secondary effects on metabolism such as the decrease in glutathione, lower availability of ascorbate, impaired mitochondrial lipid metabolism, oxidative stress, and less efficient remediation of toxic products [43][44][45][46][47][48] . Glycine is also a donor of one-carbon groups to the mitochondrial folate metabolism, through the glycine cleavage system 49,50 . ...
Article
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ALDH1L1 (10-formyltetrahydrofolate dehydrogenase), an enzyme of folate metabolism highly expressed in liver, metabolizes 10-formyltetrahydrofolate to produce tetrahydrofolate (THF). This reaction might have a regulatory function towards reduced folate pools, de novo purine biosynthesis, and the flux of folate-bound methyl groups. To understand the role of the enzyme in cellular metabolism, Aldh1l1−/− mice were generated using an ES cell clone (C57BL/6N background) from KOMP repository. Though Aldh1l1−/− mice were viable and did not have an apparent phenotype, metabolomic analysis indicated that they had metabolic signs of folate deficiency. Specifically, the intermediate of the histidine degradation pathway and a marker of folate deficiency, formiminoglutamate, was increased more than 15-fold in livers of Aldh1l1−/− mice. At the same time, blood folate levels were not changed and the total folate pool in the liver was decreased by only 20%. A two-fold decrease in glycine and a strong drop in glycine conjugates, a likely result of glycine shortage, were also observed in Aldh1l1−/− mice. Our study indicates that in the absence of ALDH1L1 enzyme, 10-formyl-THF cannot be efficiently metabolized in the liver. This leads to the decrease in THF causing reduced generation of glycine from serine and impaired histidine degradation, two pathways strictly dependent on THF.
... [12][13][14][15] In particular, glycine supplementation was indicated to protect muscles in different muscle-wasting models such as cancer cachexia, sepsis, and reduced caloric intake. 6,16,17 Earlier studies also demonstrated that dietary supplementation of glycine to DMD patients provided beneficial effect on their physical activities, although the overall effect is limited. 18 However, an interesting observation from earlier clinical studies was that glycine is more beneficial for children than adult patients, 18 implying that glycine might play other roles. ...
Article
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The need to distribute therapy evenly systemically throughout the large muscle volume within the body makes Duchenne muscular dystrophy (DMD) therapy a challenge. Cell and exon-skipping therapies are promising but have limited effects, thus enhancing their therapeutic potency is of paramount importance to increase the accessibility of these therapies to DMD patients. Here we demonstrate that co-administered glycine improves phosphorodiamidate morpholino oligomer (PMO) potency in mdx mice with marked functional improvement and up to 50-fold increase of dystrophin in abdominal muscles compared to PMO in saline. Glycine boosts satellite cell proliferation and muscle regeneration by increasing activation of mammalian target of rapamycin complex 1 (mTORC1) and replenishing the one-carbon unit pool. The expanded regenerating myofiber population then results in increased PMO uptakes. Glycine also augments the transplantation efficiency of exogenous satellite cells and primary myoblasts in mdx mice. Our data provide evidence that glycine enhances satellite cell proliferation, cell transplantation and oligonucleotide efficacy in mdx mice, and thus has therapeutic utility for cell therapy and drug delivery in muscle wasting diseases.
... Age also influenced higher serum abundance of glycine and dimethyl aminomalonic acid in 3-year-old than 5-year-old fish. Glycine is known to promote immunity, antioxidant capacity and protein biosynthesis and lipid metabolism (Wang et al., 2013;Zhong et al., 2003). ...
Preprint
This study characterised selected peripheral blood (PB) haematological parameters, liver, serum and muscle metabolic features in three‐ and five‐year old male and female giant kokopu (Galaxias argenteus) broodstock reared indoor at 16°C. Sex and age did not affect PB total cell count, and haematocrit values. However, higher erythrocytes in five‐year old fish, elevated thrombocyte and lymphocyte counts in three‐year old fish indicate age‐specific cellular regulation. Higher thrombocyte counts in female fish suggest sex‐specific regulation. At a metabolic level, liver abundance for long chain saturated fatty acids were higher in males, while females had elevated levels of polyunsaturated fatty acids. Essential and non‐essential amino acids in liver and serum were also elevated in females compared to males. These findings suggest differential allocation of fatty acids and amino acids to reflect requirements for gonadal, development and provisioning. Similarly, age significantly resulted in higher liver and serum abundances of some non‐essential amino acids in three‐year olds compared to five‐year old fish, suggesting higher metabolism in younger fish. Overall, results enhance our understanding of sex‐ and age‐based differences in fish haematology, muscle, liver, and serum metabolite profiles in healthy G. argenteus. Future studies should carefully consider potential age‐ and sex‐specific differences in metabolic responses. This article is protected by copyright. All rights reserved.
... Functions of Gly include protein synthesis, bile acid conjugation, purine synthesis, and heme synthesis (Wang wt al., 2013). With relation to immune cells, Gly is needed for Gly-gated chloride channels in leukocytes and macrophages; activation of these channels by Gly reduces cellular calcium, which is needed for the production of cytokines and superoxide, leading to potential anti-inflammatory effects (Zhong et al., 2003). Its need for purine synthesis also underscores the importance of Gly for promoting cell proliferation and differentiation. ...
Article
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Dairy cattle undergo a number of metabolic, endocrine, physiologic, and immune adaptations during the transition into lactation. Metabolically, the increase in mobilization of adipose depots as parturition approaches not only increases liver triacylglycerol accumulation, but also could trigger inflammation, oxidative stress, immune dysfunction, and reductions in liver function. The degree and length of time during which these systems remain out of balance could render cows more susceptible to disease, poor reproductive outcomes and less efficient. Thus, there continues to be interest on approaches that might synergistically help cows modulate metabolism and immune responses during the periparturient period. In the context of “immunometabolism”, varying the post-ruminal supply of micronutrients [e.g. B vitamins, folic acid, choline, trace minerals, amino acids (AA)] has been a focus of research. Classical studies in non-ruminants established a crucial role for Glu and Gln in immune cell metabolism and function. At the cellular level these AA along with essential (e.g. Met, His, Thr), semi-essential (Arg), and non-essential (Ser, Gly) AA not only interact through common biochemical pathways to help immune cells meet energy needs, but also are important for synthesis of nucleotides, antioxidants, and polyamines. From a nutritional standpoint, the 1-carbon metabolism pathway represents an example of an interconnected route through which AA could impact molecular events such as epigenetic regulation. An important “nutrient sensor” sensitive to AA supply is the mechanistic target of rapamycin (MTOR). Although MTOR has been primarily studied in the context of bovine milk protein synthesis, a growing body of literature in non-ruminants underscores its involvement in the immunometabolic response. The objective of this review is to provide an overview of immune system responses in the periparturient cow followed by more specific discussion of the immunometabolic role of specific AA. Available molecular data on immune cells and immune-responsive organs in dairy cows are discussed in the context of AA transport, cellular sensors, and signalling mechanisms that might impact responses to increases in the supply of specific AA. With nutritional management during the periparturient period continuing to be an active area of research, it is important to develop a systems understanding the potential immunometabolic role that dietary AA may play during this period.
... We therefore hypothesize that antioxidant effect observed probably involves the bioactive properties of LT components. Glycine is a component of glutathione and plays a protective role against oxidative damage by reducing cytokine production through the inhibition of Ca 2+ release [49]. Glutamine, another LT metabolite, can be converted to glutamate to reduce mitochondrial damage caused by ROS during sepsis. ...
... 66 Similar to glutamine, free glycine supplementation is also shown to reduce levels of proinflammatory cytokines and to increase levels of regulatory cytokines in several in vitro and in vivo immune models. [67][68][69] In addition, oral exposure to free glycine prevented the onset of CMA in mice, which was accompanied by a reduction in serum levels of IgG1 and IgG2a. 70 Based on these findings, it can be speculated that the immunomodulatory effects of glutamine and glycine contribute to the observed preventive effects of the AA diet on symptoms of CMA. ...
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Background: Amino acid-based formulas (AAFs) are used for the dietary management of cow's milk allergy (CMA). Whether AAFs have the potential to prevent the development and/or symptoms of CMA is not known. Objective: The present study evaluated the preventive effects of an amino acid (AA)-based diet on allergic sensitization and symptoms of CMA in mice and aimed to provide insight into the underlying mechanism. Methods: C3H/HeOuJ mice were sensitized with whey protein or with phosphate-buffered saline as sham-sensitized control. Starting 2 weeks before sensitization, mice were fed with either a protein-based diet or an AA-based diet with an AA composition based on that of the AAF Neocate, a commercially available AAF prescribed for the dietary management of CMA. Upon challenge, allergic symptoms, mast cell degranulation, whey-specific immunoglobulin levels, and FoxP3+ cell counts in jejunum sections were assessed. Results: Compared to mice fed with the protein-based diet, AA-fed mice had significantly lower acute allergic skin responses. Moreover, the AA-based diet prevented the whey-induced symptoms of anaphylaxis and drop in body temperature. Whereas the AA-based diet had no effect on the levels of serum IgE and mucosal mast cell protease-1 (mMCP-1), AA-fed mice had significantly lower serum IgG2a levels and tended to have lower IgG1 levels (P = .076). In addition, the AA-based diet prevented the whey-induced decrease in FoxP3+ cells. In sham-sensitized mice, no differences between the two diets were observed in any of the tested parameters. Conclusion: This study demonstrates that an AA-based diet can at least partially prevent allergic symptoms of CMA in mice. Differences in FoxP3+ cell counts and serum levels of IgG2a and IgG1 may suggest enhanced anti-inflammatory and tolerizing capacities in AA-fed mice. This, combined with the absence of effects in sham-sensitized mice indicates that AAFs for the prevention of food allergies may be an interesting concept that warrants further research.
... Increased levels of glycine after exposure could be due to intracellular ROS caused by NPs there by producing oxidative stress in cells. Glycine may also act as a cellular protection agent, scavenging ROS and also moderating enhanced intracellular calcium, and thereby stabilizing the plasma membrane and preventing tissue injury (Zhong et al. 2003). Planchon et al. 2017 studied the metabolomics alterations in E. coli after exposure to TiO 2 NPs under UV irradiation, and their results show that the metabolites related to growth and energy are significantly altered. ...
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This study investigated the metabolic response of E. coli after exposure to TiO2 and ZnO NPs under solar simulated irradiation. A total of 14 altered metabolites involved in two metabolic pathways were recognized using multivariate analysis. Polyamine, putrescine was elevated in ZnO-treated group, as an adaptation to oxidative stress in cells, whereas it was significantly reduced in TiO2-treated group. Glycine levels also were elevated in both the treatment groups, showing cellular protection in cells after exposure. In addition, glycine, serine, and threonine metabolism and arginine and proline metabolism were altered in ZnO and TiO2-treated groups respectively.
... γ-Glutamylglycine, which is the lead metabolite for a cluster that includes glycine, was inversely associated with both BMI and WC as well as CRP. Decreased levels of glycine, which has been extensively linked to inflammation (42), could influence this process through its effect on the antioxidant glutathione, which requires glycine for its synthesis, or by altering immune cell production of proinflammatory cytokines (43). However, the link between this amino acid and CRP appears to be mostly independent of adiposity because the association was only 15% attenuated when BMI was controlled for. ...
Article
Objective: This study was undertaken to identify metabolites associated with BMI and waist circumference (WC) in women and to determine whether these metabolites are associated with biomarkers of metabolic health. Methods: Untargeted metabolomic analysis was done on serum from 1,534 women. Metabolites associated with BMI and WC were identified using linear regression with a Bonferroni-corrected P value. Clustered blocks of these metabolites were then defined whose association with the anthropometric measures could be represented by a single metabolite. The association of these representative metabolites with biomarkers for diabetes and inflammation was then determined. Results: About one-third of 781 metabolites included in the analyses were associated with BMI and/or WC. Associations were found for some novel metabolites, including several sphingolipids, nucleotides, and modified fatty acids. Among metabolites most strongly inversely associated with BMI, the choline-containing plasmalogen (O-16:0/18:1) (β = -0.30, P = 6.62 × 10-32 ) was also inversely associated with c-peptide and positively associated with adiponectin. Adjustment for BMI attenuated the metabolite-biomarker associations more for hemoglobin A1c (> 100%) and c-peptide (58.8% to > 100%) than for C-reactive protein (10.5%-40.0%) and adiponectin (7.0%-30.4%). Conclusions: These results add to the list of metabolites associated with adiposity and indicate that some may influence processes that contribute to the development of obesity-related diseases.
... TGFβ can start the inflammatory path through ROS [61]. On the other hand, L-lysine prevents hyp-oxia, formation of free radicals, and activation of inflammatory cytokines through affecting inflammatory cells such as macrophages [62]. A study reported that L-lysine increased microglial M2 polarization and reduced inflammatory response in both in vitro and in vivo conditions, indicating its potential protective effects in the nervous system [25]. ...
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Introduction: Diabetic nephropathy is one of the leading causes of end-stage renal disease worldwide. Uncontrolled hyperglycemia and subsequent production of glycation end-products activate the paths which lead to diabetic nephropathy. The aim of this study was to assess the effects of L-lysine on antioxidant capacity, biochemical factors, kidney function, HSP70 level, and the expression of the TGFβ, VEGF, and RAGE genes in rats with streptozocin-induced diabetes mellitus. Methods: Thirty-two male Wistar rats were randomly allocated to four eight-rat groups, namely, a healthy group, a diabetic group treated with vehicle (DM + vehicle), a diabetic group treated with L-lysine (DM + Lys), and a healthy group treated with L-lysine (healthy + Lys). Rats in the DM + Lys and the healthy + Lys groups were treated with L-lysine 0.15%. The levels of fasting blood glucose, insulin, HbA1C, advanced glycation end-products (AGEs), lipid profile, serum creatinine, blood urea nitrogen, glomerular filtration rate, urine microalbumin, oxidative stress parameters, kidney histology and morphology, and TGFβ, VEGF, and RAGE gene expressions were assessed. Findings. An eight-week treatment with L-lysine significantly reduced the levels of fasting blood glucose, AGEs, kidney function parameters, oxidative stress parameters, lipid profile, and the TGFβ, VEGF, and RAGE gene expression and significantly increased the levels of serum insulin and tissue HSP70. Conclusion: Treatment with L-lysine seems to slow down the progression of diabetic nephropathy.
... Surprisingly, however, glycine's potential to promote intestinal health appears so far to have received little if any study. When improvement of intestinal barrier function is desired to counter systemic or hepatic inflammation, it is pertinent to note that supplemental glycine can act via its receptor to exert anti-inflammatory effects on a range of cell types, and that it also serves as a substrate for synthesis of the protective cellular antioxidant glutathione (31,32). ...
Article
Impairment of intestinal barrier function is linked to certain pathologies and to aging, and can be a cause of bacterial infections, systemic and hepatic inflammation, food allergies, and autoimmune disorders. The formation and maintenance of intestinal tight junctions is supported by glucagon-like peptide-2 (GLP-2), which via insulin-like growth factor I activity boosts phosphoinositide 3-kinase/Akt/mammalian target of rapamycin complex 1 (PI3K/Akt/mTORC1) signaling in enterocytes. 5'-AMP-activated protein kinase (AMPK) activity as well as estrogen receptor-β (ERβ) activity are also protective in this regard. Conversely, activation of mitogen-activated protein kinases (MAPKs) and cellular Src (c-Src) under inflammatory conditions can induce dissociation of tight junctions. Hence, nutraceuticals that promote GLP-2 secretion from L cells-effective pre/probiotics, glycine, and glutamine-as well as diets rich in soluble fiber or resistant starch, can support intestinal barrier function. AMPK activators-notably berberine and the butyric acid produced by health-promoting microflora-are also beneficial in this regard, as are soy isoflavones, which function as selective agonists for ERβ. The adverse impact of MAPK and c-Src overactivation on the intestinal barrier can be combatted with various antioxidant measures, including phycocyanobilin, phase 2-inducer nutraceuticals, and N-acetylcysteine. These considerations suggest that rationally designed functional foods or complex supplementation programs could have clinical potential for supporting and restoring healthful intestinal barrier function.
... Thus, exogenous supplementation could potentially satisfy this need, and oral glycine has been reported to increase serum glycine, as well as ameliorating cognitive and depressive symptoms [8,63]. However, despite its substantial protective effect [64], there is evidence that excessive glycine intake can lead to toxicity [65]. Therefore, identifying a glycine transport pathway disorder in the intestine and describing the relationships between intestinal glycine and depressive behavior could reveal diversified and safe approaches for the treatment of this symptom. ...
Article
Aims: To clarify the role of the gut-brain axis in depression. Main methods: We used the iTRAQ technique to identify differential proteins in the intestine of the rat model of chronic unpredictable mild stress (CUMS)-induced depression. Significant differential proteins were subjected to Gene Ontology (GO) functional annotations and KEGG pathway enrichment analysis. Key proteins were validated at the mRNA and protein levels. The levels of cytokines in the intestine, serum and hypothalamus were examined by ELISA. HPLC-UV was used to detect the levels of amino acids. Key findings: In the rat intestine, 349 differential proteins (209 downregulated, 140 upregulated) were identified. GO analysis indicated that "protein complex assembly" was the first-ranked biological process. SNARE complex components, including SNAP23, VAMP3 and VAMP8, were increased at the mRNA levels, while only VAMP3 and VAMP8 were also upregulated at the protein level. TNFα, IL6 and IL1β were upregulated in the CUMS rat intestine, while TNFα was decreased in the serum and hypothalamus. IL1β was decreased in the serum. "Protein digestion and absorption" was the most significantly enriched KEGG pathway, involving 5 differential proteins: SLC9A3, ANPEP, LAT1, ASCT2 and B0AT1. Glutamine, glycine and aspartic acid were perturbed in the CUMS rat intestine. Significance: Our findings suggest that CUMS enhances the adaptive immune response in the intestine through ER-phagosome pathway mediated by SNARE complex and disturb absorption of amino acids. It advances our understanding of the role of gut-brain axis in depression and provides a potential therapeutic target for the disease.
... Anti-inflammatory, immunomodulatory, and cytoprotective effects of glycine have each been linked to different intracellular signaling pathways [28]. We found that glycinebased powder activates the NF-kB pathway. ...
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Objectives Air-polishing has been used in the treatment of periodontitis and gingivitis for years. The introduction of low-abrasive powders has enabled the use of air-polishing devices for subgingival therapy. Within the last decade, a wide range of different low-abrasive powders for subgingival use has been established. In this study, the effects of a glycine powder and a trehalose powder on human gingival fibroblasts (HGF) were investigated. Methods HGF were derived from three systemically and periodontally healthy donors. After 24 h and 48 h of incubation time, mRNA levels, and after 48 h, protein levels of TNFα, IL-8, CCL2, and VEGF were determined. In addition, NF-κB p65 nuclear translocation and in vitro wound healing were assessed. Statistical analysis was performed by ANOVA and post hoc Dunnett’s and Tukey’s tests ( p < 0.05). Results Glycine powder significantly increased the expression of proinflammatory genes and showed exploitation of the NF-κB pathway, albeit trehalose powder hardly interfered with cell function and did not trigger the NF-κB pathway. In contrast to trehalose, glycine showed a significant inhibitory effect on the in vitro wound healing rate. Conclusion Subgingivally applicable powders for air-polishing devices can regulate cell viability and proliferation as well as cytokine expression. Our in vitro study suggests that the above powders may influence HGF via direct cell effects. Trehalose appears to be relatively inert compared to glycine powder.
... Glycine, the simplest protein-forming amino acid (NH 2 -CH 2 -COOH, MW = 75.067 g/mol), is relatively cheap with many impressive health benefits [32,33]. Because of the hydrogen in the glycine side chain, it may integrate both hydrophilic and hydrophobic environments inside the polypeptide chain which helps the contaminant adsorption in aquatic solution. ...
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In the present work the removal of organic pollutants from wastewater was studied using a computational simulation method. Two nanospherical porous boron nitride (BN) materials namely, B16N16 and B12N12, were selected as adsorbent and the removal mechanism and adsorption ability of pure and glycine functionalized boron nitride adsorbents (B16N16(Glycine)2/B12N12(Glycine)2) were comprehensively evaluated in removal of two different emerging contaminants. The sigma profile (or charge density) study along with the quantum chemical calculations (using Materials Studio software) were obtained and discussed to predict the contaminant removal process. In particular, the adsorption ability and possible changes in the spectroscopic and electronic properties (Frontier molecular orbital, energy gap (ΔEGAP), chemical softness (σ), hardness (η)) of the pure and functionalized BN adsorbents before and after adsorption processes were studied. It was found that both functionalized adsorbents (B16N16(Glycine)2 and B12N12(Glycine)2) had higher adsorption ability. Moreover, according to the quantum chemical calculations B16N16(Glycine)2 adsorbent showed higher chemical reactivity and adsorption ability compare to other studied adsorbents due to the formation of cage interactions between pollutants and amino acid glycine of BN. According to the outcomes, Functionalization of the nanospherical boron nitride materials with glycine led to improvement in the pollutants adsorption affinity.
... 35 Interestingly, glycine has been associated with broad anti-inflammatory properties, ischemia/reperfusion and thermic shock protection. 36 On the opposite, N-methylalanine was negatively correlated with active inflammation in patients with rheumatoid arthritis. 37 At last, inulobiose is an exogenous metabolite derived from inuline which is not reabsorbed after glomerular filtration. ...
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Background Operational tolerance is the holy grail in solid organ transplantation. Previous reports showed that the urinary compartment of operationally tolerant recipients harbor a specific and unique profile. We hypothesized that spontaneous tolerant kidney transplanted recipients (KTR) would have a specific urinary metabolomic profile associated to operational tolerance. Methods We performed metabolomic profiling on urine samples from healthy volunteers, stable KTR under standard and minimal immunosuppression and spontaneous tolerant KTR using liquid chromatography in tandem with mass spectrometry. Supervised and unsupervised multivariate computational analyses were used to highlight urinary metabolomic profile and metabolite identification thanks to workflow4metabolomic platform. Findings The urinary metabolome was composed of approximately 2700 metabolites. Raw unsupervised clustering allowed us to separate healthy volunteers and tolerant KTR from others. We confirmed by two methods a specific urinary metabolomic signature in tolerant KTR mainly driven by kynurenic acid independent of immunosuppressive drugs, serum creatinine and gender. Interpretation Kynurenic acid and tryptamine enrichment allowed the identification of putative pathways and metabolites associated with operational tolerance like IDO, GRP35 and AhR and indole alkaloids. Funding This study was supported by the ANR, IRSRPL and CHU de Nantes.
... In addition to the role of glycine in the CNS as an inhibitory neurotransmitter, glycine has a regulatory role in the periphery and adjusts glucose homeostasis via insulin secretion and other pathways. Through ligandgated chloride channels in macrophages and leukocytes, glycine modulates intracellular calcium concentration and thereby has important roles in regulating immune function, generating superoxide and the production of cytokines [7]. Glycine also acts as a co-ligand for N-methyl-d-aspartate (NMDA) glutamate receptors. ...
Article
PurposeGlycine is the simplest and major amino acid in humans. It is mainly generated in the liver and kidney and is used to produce collagen, creatine, glucose and purine. It is also involved in immune function, anti-inflammatory processes and anti-oxidation reactions. Here, we reviewed the current evidence supporting the role of glycine in the development and treatment of metabolic syndrome components.Methods We searched Scopus, PubMed and EMBASE databases for papers concerning glycine and metabolic syndrome.ResultsAvailable evidence shows that the amount of glycine synthesized in vivo is insufficient to meet metabolic demands in these species. Plasma glycine levels are lower in subjects with metabolic syndrome than in healthy individuals. Interventions such as lifestyle modification, exercise, weight loss, or drugs that improve manifestations of metabolic syndrome remarkably increase circulating glycine concentrations.Conclusion Glycine supplementation improves various components of metabolic syndrome including diabetes, obesity, hyperlipidemia and hypertension. In the future, the use of glycine may have a significant clinical impact on the treatment of patients with metabolic syndrome.
... Within the two smaller clusters protein tyrosine phosphatase sigma (PTPRS) is expressed in dendritic cells and has been shown to regulate interferon (Bunin et al., 2015) while both UNC5A and DSCAML1 are receptors that belong to the immunoglobin family (Lai Wing Sun et al., 2011;Ly et al., 2008). SLC6A9 is a glycine transporter and glycine is important in immune modulation (Zhong et al., 2003) as well as an inhibitory neurotransmitter in the central nervous system (Legendre, 2001;Umeda et al., 2019). ...
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Exposure to violence (ETV) has been linked to epigenomics mechanisms such as DNA methylation (DNAm). We used epigenetic profiling of blood collected from 32 African American young adult males who lived in Washington DC to determine if changes in DNAm at CpG sites affiliated with nervous and immune system were associated with exposure to violence. Pathway analysis of differentially methylated regions comparing high and low ETV groups revealed an enrichment of gene sets annotated to nervous system and immune ontologies. Many of these genes are known to interact with each other which suggests DNAm alters gene function in the nervous and immune system in response to ETV. Using data from a unique age group, young African American adult males, we provide evidence that lifetime ETV could impact DNA methylation in genes impacted at Central Nervous System and Immune Function sites. Method Methylation analysis was performed on DNA collected from the blood of participants classified with either high or low lifetime ETV. Illumina®MethylationEPIC Beadchips (∼850k CpG sites) were processed on the iScan System to examine whole-genome methylation differences. Differentially methylated CpG-sites between high (n=19) and low (n=13) groups were identified using linear regression with violence and substance abuse as model covariates. Gene ontology analysis was used to identify enrichment categories from probes annotated to the nearest gene. Results A total of 595 probes (279 hypermethylated; 316 hypomethylated) annotated to 383 genes were considered differentially methylated in association with ETV. Males with high ETV showed elevated methylation in several signaling pathways were most impacted at Central Nervous System and Immune Function sites. Eight candidate genes were identified that play important biological roles in stress response to violence with HDAC4 (10%), NR4A3 (11%), NR4A2 (12%), DSCAML1(12%), and ELAVL3 (13%) exhibiting higher levels in the low ETV group and DLGAP1 (10%), SHANK2 (10%), and NRG1(11%) having increased methylation in the high ETV group. These findings suggest that individuals subjected to high ETV may be at risk for poor health outcomes that have not been reported previously.
... Other amino acids are absorbed by the small intestines and arrive in the liver via the portal vein (Hou et al., 2020). Synthesis of tyrosine, precursor for the synthesis of catecholamine neurotransmitters Fernstrom and Fernstrom, 2007;Matthews, 2007 Tryptophan Serotonin and melatonin synthesis, kynurenine pathway Stavrum et al., 2013 Tyrosine Precursor for the synthesis of catecholamine neurotransmitters and thyroid hormones Levine and Conn, 1967 Branched-chain amino acids Isoleucine Improvement of insulin resistance and immune function Doi et al., 2007;Gu et al., 2019 Leucine Regulation of protein turn-over, inhibition of proteolysis Wu, 2009;Duan et al., 2016 Valine Improvement of immune function, contribution of de novo lipogenesis of odd-chained fatty acids Regulation of immune function, ammonia detoxification Li et al., 2007;Wu et al., 2009 Aspartate Substrate in urea cycle and nucleotide synthesis, activation of NMDA receptors, Wu, 2009;Zhu et al., 2017 Cysteine Synthesis of anti-oxidants, crucial role in protein structure and protein-folding pathways Brosnan and Brosnan, 2006b;Colovic et al., 2018 Glutamate Excitatory neurotransmitter, ammonia assimilation He et al., 2010;Zhou and Danbolt, 2014 Glutamine Substrate in urea cycle, for gluconeogenesis and nucleotide synthesis, energy substrate for cells of the immune system; regulating the proliferation and activation of hepatic stellate cells Newsholme et al., 2003;Li et al., 2017;Zhu et al., 2017 Glycine Inhibitory neurotransmitter, anti-oxidant, regulates production of cytokines and immune function Brosnan, 2001;Fang et al., 2002;Zhong et al., 2003 Histidine Hemoglobin structure and function, modulation angiogenesis, cell adhesion and migration, complement activation, immune complex clearance and phagocytosis of apoptotic cells Proline Protein metabolism, collagen structure and function, wound healing, anti-oxidant reactions, immune function Wu, 2009;Wu et al., 2011 Serine Protein phosphorylation, nucleotide synthesis, one-carbon unit metabolism Wu, 2009 Threonine Immune function, synthesis of mucin protein required for intestinal integrity Wu, 2009;Mao et al., 2011 ...
... Notably, we found that Gly supplementation significantly abolished upregulated mRNA levels of pro-inflammatory cytokines and chemokines in the jejunum and colon tissues, as well as inflammatory cell infiltration in the colon induced by LPS, confirming an anti-inflammatory role of Gly. Gly has long been categorized as an anti-inflammatory agent (Zhong et al. 2003), by binding to the Gly receptor in immune cells, blocking the increase of intracellular calcium (Van den Eynden et al. 2009). More studies are needed to explore whether this effect is involved in our study. ...
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Intestinal dysfunction is commonly observed in humans and animals. Glycine (Gly) is a functional amino acid with anti-inflammatory and anti-apoptotic properties. The objective of this study was to test the protective effects of Gly against lipopolysaccharide (LPS)-induced intestinal injury. 28 C57BL/6 mice with a body weight (BW) of 18 ± 2 g were randomly assigned into four groups: CON (control), GLY (orally administered Gly, 5 g/kg BW/day for 6 days), LPS (5 mg/kg BW on day 7, i. p.), and GLY + LPS (Gly pretreatment and LPS administration). Histological alterations, inflammatory responses, epithelial cell apoptosis, and changes of the intestinal microbiota were analyzed. Results showed that, compared with the CON group, mice in the LPS treatment group showed decreased villus height, increased crypt depth, and decreased ratio of villus height to crypt depth, which were significantly attenuated by Gly. Neither LPS nor Gly treatment altered morphology of the distal colon tissues. LPS increased the apoptosis of jejunum and colon epithelial cells and protein abundance of cleaved caspase3 in the jejunum, which were markedly abrogated by Gly. LPS also elevated the mRNA levels of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MYD88), pro-inflammatory cytokines, and chemokines in the jejunum and colon. These alterations were significantly suppressed by Gly. In addition, Gly supplementation attenuated infiltration of CD4+, CD8+ T-lymphocytes, CD11b+ and F4/80+ macrophages in the colon. Furthermore, Gly increased the relative abundance of Mucispirillum, Lachnospiraceae-NK4A136-group, Anaerotruncus, Faecalibaculum, Ruminococcaceae-UCG-014, and decreased the abundance of Bacteroides at genus level. Supplementation with Gly might be a nutritional strategy to ameliorate LPS-induced intestinal injury in mice.
... Age also influenced higher serum abundance of glycine and dimethyl aminomalonic acid in 3-year-old than 5-year-old fish. Glycine is known to promote immunity, antioxidant capacity and protein biosynthesis and lipid metabolism (Wang et al., 2013;Zhong et al., 2003). ...
Article
This study characterised selected peripheral blood (PB) haematological parameters, liver, serum and muscle metabolic features in three‐ and five‐year old male and female giant kokopu (Galaxias argenteus) broodstock reared indoor at 16°C. Sex and age did not affect PB total cell count, and haematocrit values. However, higher erythrocytes in five‐year old fish, elevated thrombocyte and lymphocyte counts in three‐year old fish indicate age‐specific cellular regulation. Higher thrombocyte counts in female fish suggest sex‐specific regulation. At a metabolic level, liver abundance for long chain saturated fatty acids were higher in males, while females had elevated levels of polyunsaturated fatty acids. Essential and non‐essential amino acids in liver and serum were also elevated in females compared to males. These findings suggest differential allocation of fatty acids and amino acids to reflect requirements for gonadal, development and provisioning. Similarly, age significantly resulted in higher liver and serum abundances of some non‐essential amino acids in three‐year olds compared to five‐year old fish, suggesting higher metabolism in younger fish. Overall, results enhance our understanding of sex‐ and age‐based differences in fish haematology, muscle, liver, and serum metabolite profiles in healthy G. argenteus. Future studies should carefully consider potential age‐ and sex‐specific differences in metabolic responses.
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Activation of various isoforms of NADPH oxidase contributes to the pathogenesis of asthma at multiple levels: promoting hypercontractility, hypertrophy, and proliferation of airway smooth muscle; enabling lung influx of eosinophils via VCAM-1; and mediating allergen-induced mast cell activation. Free bilirubin, which functions physiologically within cells as a feedback inhibitor of NADPH oxidase complexes, has been shown to have a favorable impact on each of these phases of asthma pathogenesis. The spirulina chromophore phycocyanobilin (PhyCB), a homolog of bilirubin's precursor biliverdin, can mimic the inhibitory impact of biliverdin/bilirubin on NADPH oxidase activity, and spirulina's versatile and profound anti-inflammatory activity in rodent studies suggests that PhyCB may have potential as a clinical inhibitor of NADPH oxidase. Hence, spirulina or PhyCB-enriched spirulina extracts merit clinical evaluation in asthma. Promoting biosynthesis of glutathione and increasing the expression and activity of various antioxidant enzymes - as by supplementing with N-acetylcysteine, Phase 2 inducers (eg, lipoic acid), selenium, and zinc - may also blunt the contribution of oxidative stress to asthma pathogenesis. Nitric oxide (NO) and hydrogen sulfide (H2S) work in various ways to oppose pathogenic mechanisms in asthma; supplemental citrulline and high-dose folate may aid NO synthesis, high-dose biotin may mimic and possibly potentiate NO's activating impact on soluble guanylate cyclase, and NAC and taurine may boost H2S synthesis. The amino acid glycine has a hyperpolarizing effect on airway smooth muscle that is bronchodilatory. Insuring optimal intracellular levels of magnesium may modestly blunt the stimulatory impact of intracellular free calcium on bronchoconstriction. Nutraceutical regimens or functional foods incorporating at least several of these agents may have utility as nutraceutical adjuvants to standard clinical management of asthma.
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The neurotransmitter levels of representatives from five different diagnosis groups were tested before and after participation in the MNRI®—Masgutova Neurosensorimotor Reflex Intervention. The purpose of this study was to ascertain neurological impact on (1) Developmental disorders, (2) Anxiety disorders/OCD (Obsessive Compulsive Disorder), PTSD (Post-Traumatic Stress disorder), (3) Palsy/Seizure disorders, (4) ADD/ADHD (Attention Deficit Disorder/Attention Deficit Disorder Hyperactive Disorder), and (5) ASD (Autism Spectrum Disorder) disorders. Each participant had a form of neurological dysregulation and typical symptoms respective to their diagnosis. These diagnoses have a severe negative impact on the quality of life, immunity, stress coping, cognitive skills, and social assimilation. This study showed a trend towards optimization and normalization of neurological and immunological functioning, thus supporting the claim that the MNRI method is an effective non-pharmacological neuromodulation treatment of neurological disorders. The effects of MNRI on inflammation have not yet been assessed. The resulting post-MNRI changes in participants’ neurotransmitters show significant adjustments in the regulation of the neurotransmitter resulting in being calmer, a decrease of hypervigilance, an increase in stress resilience, behavioral and emotional regulation improvements, a more positive emotional state, and greater control of cognitive processes. In this paper, we demonstrate that the MNRI approach is an intervention that reduces inflammation. It is also likely to reduce oxidative stress and encourage homeostasis of excitatory neurotransmitters. MNRI may facilitate neurodevelopment, build stress resiliency, neuroplasticity, and optimal learning opportunity. There have been no reported side effects of MNRI treatments.
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Background Glycine is a dietary non-essential amino acid that is low in obesity and increases following bariatric surgery. However, the exact mechanism responsible remains unclear and it is unknown whether hypoglycinemia is a cause or consequence of insulin resistance. Objective Using multiple isotopically labeled tracers, we aimed to determine the underlying kinetic changes responsible for hypoglycinemia in obesity by: 1) Comparing glycine kinetics between participants with morbid obesity (BMI ≥ 32.5 kg/m ² ) to those with healthy weight (BMI < 25 kg/m ² ), and 2) Comparing glycine kinetic changes in participants with morbid obesity after bariatric surgery. Methods [1,2- ¹³ C 2 ] glycine, [2,3,3- ² H 3 ] serine, and [ ² H 5 ] phenylalanine were infused to compare the glycine kinetic parameters between 21 participants with morbid obesity and 21 controls with healthy weight. Participants with morbid obesity then underwent bariatric surgery and 17 were re-studied 6 months later. Data were analyzed by non-parametric methods and presented as median (interquartile range). Results Compared to controls, participants with morbid obesity had significantly lower plasma glycine concentrations at 163 (153-171) vs. 201 (172-227) µmol/L and significantly reduced de novo glycine synthesis rate at 86.2 (64.5-111) vs.124 (103-159) µmol·kg LBM ⁻¹ ·h ¹ , p < 0.001. Following surgery, body weight and insulin resistance decreased and this was accompanied by significant increases in plasma glycine concentration to 210 (191-243) µmol/L as well as the de novo glycine synthesis rate to 127 (98.3-133) µmol·kg LBM ⁻¹ ·h ⁻¹ , p < 0.001 vs. baseline. Conclusion Hypoglycinemia in participants with morbid obesity was associated with impaired de novo glycine synthesis. The increase in plasma glycine concentration and de novo glycine synthesis plus the marked improvement in insulin resistance after bariatric surgery suggest that hypoglycinemia may be secondary to impaired glycine synthesis because of obesity-induced insulin resistance. Clinical Trial Registration [ https://tinyurl.com/6wfj7yss ], identifier [NCT04660513].
Chapter
Periodontitis is a major public health problem, that can have local and systemic consequences ranging from tooth loss to the aggravation of other chronic diseases. The consequences of which have an impact on patient's overall general health and quality of life. Periodontal treatments include a large range of techniques and concepts from plaque control to periodontal debridement, surgery and regeneration. Regardless of the treatment proposed, it always begins with the same first essential simple step that is etiological therapy which includes oral hygiene management and the control of periodontal risk factors. The aim of this first step, presented in this chapter, consists mainly in reducing oral bacterial load and inflammation by the means of daily oral hygiene methods and sub-gingival biofilm disruption. Although understanding of the pathogenesis and molecular and cellular mechanisms involved in periodontitis has increased, treatment wise, non-surgical debridement remains the keystone of every periodontal treatment and supportive periodontal therapy. Once risk factors are monitored and plaque control mastered by the patient, root instrumentation can be performed with hand or power-driven instruments. However effective, sub-gingival biofilm disruption has some limits and can be improved with adjunctive therapies such as antiseptics, antibiotics, air polishing or other emerging devices and therapies. Unfortunately, the lack of clear clinical guidelines, concerning these adjunctive therapies, still remains, thus pointing out the necessity of more standardized clinical studies. Also, if some patients can return to a healthy periodontal state, most periodontal patients will remain at periodontal risk for life. Proper assessment of the patient's periodontal risk will help establish correct monitoring of patients successfully treated for their periodontal disease.
Article
Background Glycine is a proteogenic amino acid that is required for numerous metabolic pathways, including purine, creatine, heme and glutathione biosynthesis. Glycine formation from serine, catalyzed by serine hydroxy methyltransferase, is the major source of this amino acid in humans. Our previous studies in a mouse model have shown a crucial role for the10-formyltetrahydrofolate dehydrogenase (ALDH1L1) enzyme in serine to glycine conversion. Objectives To determine the genomic influence on serine-glycine ratio in 803 Hispanic children from 319 families of the Viva La Familia cohort. Methods We performed a genome-wide association analysis for plasma serine, glycine, and serine-glycine ratio in SOLAR while accounting for non-independence among family members. Results All three parameters were significantly heritable [h2 = 0.22–0.78, P < 0.004]. The strongest associations for serine-glycine ratio were with single nucleotide polymorphisms (SNPs) in ALDH1L1 and glycine decarboxylase (GLDC) and for glycine with GLDC [P < 3.5 × 10–8, effect sizes: 0.03–0.07]. No significant associations were found for serine. We also conducted a targeted genetic analysis with ALDH1L1 exonic SNPs and found significant association between serine-glycine ratio and rs2886059 [β (SE) = 0.68 (0.25), P = 0.006] and rs3796191 [β (SE) = 0.25 (0.08), P = 0.003], and glycine and rs3796191 [β (SE) = –0.08 (0.02), P = 0.0004]. These exonic SNPs were further associated with metabolic disease risk factors, mainly adiposity measures [P < 0.006]. Significant genetic and phenotypic correlations were found for glycine and serine-glycine ratio with metabolic disease risk factors including adiposity, insulin sensitivity and inflammation-related phenotypes [ρg = –0.37 to 0.35, P < 0.03, ρp = –0.19 to 0.13, P < 0.006]. The significant genetic correlations indicate shared genetic effects among glycine, serine-glycine ratio, and adiposity and insulin sensitivity phenotypes. Conclusions Our study suggests that ALDH1L1 and GLDC SNPs influence serine to glycine ratio and metabolic disease risk.
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Two cDNAs encoding variants (alpha 1 and alpha 2) of the strychnine binding subunit of the inhibitory glycine receptor (GlyR) were isolated from a human fetal brain cDNA library. The predicted amino acid sequences exhibit approximately 99% and approximately 76% identity to the previously characterized rat 48 kd polypeptide. Heterologous expression of the human alpha 1 and alpha 2 subunits in Xenopus oocytes resulted in the formation of glycine-gated strychnine-sensitive chloride channels, indicating that both polypeptides can form functional GlyRs. Using a panel of rodent-human hybrid cell lines, the gene encoding alpha 2 was mapped to the short arm (Xp21.2-p22.1) of the human X chromosome. In contrast, the alpha 1 subunit gene is autosomally located. These data indicate molecular heterogeneity of the human GlyR at the level of alpha subunit genes.
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Two different isoforms of the inhibitory glycine receptor were identified during postnatal development of rat spinal cord. A neonatal form characterized by low strychnine binding affinity, altered antigenicity, and a ligand binding subunit differing in mol. wt (49 kd) from that of the adult receptor (48 kd) predominates at birth (70% of the total receptor protein). Separation from the adult form could be achieved by either use of a selective antibody or glycine gradient elution of 2-aminostrychnine affinity columns. Both isoforms co-purify with the mol. wt 93 kd peripheral membrane protein of the postsynaptic glycine receptor complex.
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Glycine, strychnine and certain chloride channel blockers were reported to protect cells against lethal cell injury. These effects have been attributed to interactions with membrane proteins related to CNS glycine gated chloride channel receptors. We have investigated the pharmacology of these actions. Madin-Darby canine kidney (MDCK) epithelial cells were depleted of adenosine triphosphate (ATP) by incubation in glucose free medium containing a mitochondrial uncoupler. Medium Ca2+ was adjusted to 100 nM in the presence of an ionophore such that intracellular Ca2+ did not increase, and Ca(2+)-related injury mechanisms were inhibited. This permitted more sensitive quantitation of protection against cell injury attributable to glycine or other agents whose actions might be related to those of the amino acid. Two classes of compounds showed cytoprotective activity in this system: (1) ligands at chloride channel receptors, such as glycine, strychnine and avermectin B1a; (2) chloride channel blockers, including cyanotriphenylboron and niflumic acid, both of which are known to bind to channel domains of CNS glycine receptors. Morphological and functional studies showed that the compounds preserved plasma membrane integrity, but permitted cell swelling. Substitution of medium chloride by gluconate, or chloride salts by sucrose, did not substantially modify lethal damage or its prevention by glycine or other drugs. The compounds did not modify ATP declines. At least for some compounds, cytoprotection appeared to be specific to structural features on the molecules. These observations are consistent with the hypothesis that a plasma membrane protein related to glycine-gated chloride channel receptors plays a significant role in cell injury, but indicate that the mechanisms of injury and protection by compounds active in this system are not related to chloride fluxes.
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1. 1. Strychnine and a series of related compounds, known to depress the postsynaptic inhibition of spinal motoneurones, were applied electrophoretically to motoneurones located within lumbar segments of cats anaesthetised with pentobarbital sodium. 2. 2. Difficulty was encountered in controlling the efflux of these agents from the drug-containing outer barrel of co-axial electrodes. Nevertheless the agents clearly depressed the hyperpolarizing inhibitory potentials which were evoked by a variety of afferent impulses and recorded by intracellular electrodes. 3. 3. The membrane potentials and excitatory postsynaptic potentials of motoneurones were not affected by concentrations of these compounds sufficient to abolish inhibitory post-synaptic potentials.
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L-2-oxothiazolidine-4-carboxylic acid (OTC) is a cysteine prodrug that maintains glutathione in tissues. Here, its effect on alcohol-induced liver injury in an enteral alcohol feeding model was investigated. Male Wistar rats were given control high-fat or ethanol containing diets enterally for 4 weeks. Treated rats received 500 mg/kg/d of dietary OTC. Ethanol delivery, weight gain, and the cyclic pattern of ethanol in the urine were not different between the OTC-ethanol and ethanol groups. After 4 weeks, serum aspartate transaminase (AST), necrosis and inflammation were elevated significantly by ethanol compared with appropriate high-fat controls, effects blocked by OTC. Moreover, ethanol elevated hepatic tumor necrosis factor alpha (TNF-alpha) messenger RNA (mRNA) and the nuclear transcription factor nuclear factor kappaB (NFkappaB) 2-3 fold. NFkappaB in isolated Kupffer cells was also increased by ethanol. These effects were all blocked by OTC treatment. Additionally, superoxide production was higher in Kupffer cells isolated from ethanol-treated rats, an effect blunted by OTC. OTC also increased circulating glutathione (GSH) levels about 2-fold; however, GSH levels were not affected by ethanol or OTC in livers from the groups studied. Surprisingly, GSH was elevated by ethanol and OTC treatment in isolated Kupffer cells about 2-fold. Moreover, GSH (Ki-10 micromol/L) and cysteinyl-glycine, but not oxidized glutathione (GSSG) or OTC, blunted the LPS-induced increase in calcium in isolated Kupffer cells, possibly by activating a glycine-gated chloride channel due to their structural similarity with glycine. Collectively, it is concluded that GSH is protective, in part, by increasing circulating GSH, which blunts activation of Kupffer cells via the glycine-gated chloride channel.
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mdash;: The goal of this study was to investigate whether prefeeding of glycine reduces the immunoinflammatory response, the degree of distant organ injury (liver), and/or the mortality rate in a two-hit model using intestinal ischemia/reperfusion and endotoxin (ET) challenge 6 h later in rats. The liver damage was greatest at 24 h after ET challenge and completely inhibited by glycine. The early systemic increase of the proinflammatory cytokines tumor necrosis factor-[alpha] (TNF-[alpha]) and interleukin (IL) -6 as well as the secretion of the antiinflammatory cytokine IL-10 was reduced by glycine. Tissue cytokine mRNA expression (TNF-[alpha], IL-1[beta], IL-10) was decreased in the lung and the liver but not in the mesenteric lymph node or ileum, in the glycine-fed group. However, glycine did not decrease the mortality rate. These results suggest that prefeeding of glycine reduces liver damage as well as the systemic and local (lung and liver) inflammatory response after intestinal ischemia/reperfusion and endotoxin challenge in rats. (C)2001The Shock Society
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Reactive molecules O−2, H2O2, and nitrogen monoxide (NO) are produced from macrophages following exposure to lipopolysaccharide (LPS) and involved in cellular signaling for gene expression. Experiments were carried out to determine whether these molecules regulate inducible nitric oxide synthase (iNOS) gene expression in RAW264.7 macrophages exposed to LPS. NO production was inhibited by the antioxidative enzymes catalase, horseradish peroxidase, and myeloperoxidase but not by superoxide dismutase (SOD). In contrast, the NO-producing activity of LPS-stimulated RAW264.7 cells was enhanced by the NO scavengers hemoglobin (Hb) and myoglobin. The antioxidant enzymes decreased levels of iNOS mRNA and protein in LPS-stimulated RAW264.7 cells, whereas the NOS inhibitor NG-monomethyl--argine as well as Hb increased the level of iNOS protein but not mRNA, indicating that NO inhibits iNOS protein expression. NF-κB was activated in LPS-stimulated RAW264.7 cells and the activation was significantly inhibited by antioxidant enzymes, but not by Hb. Similar results were obtained using LPS-stimulated rodent peritoneal macrophages. Extracellular O−2 generation by LPS-stimulated macrophages was suppressed by SOD, but not by antioxidative enzymes, while accumulation of intracellular reactive oxygen species was inhibited by antioxidative enzymes, but not by SOD. Exogenous H2O2 induced NF-κB activation in macrophages, which was inhibited by catalase and pyrroline dithiocarbamate (PDTC). H2O2 enhanced iNOS expression and NO production in peritoneal macrophages when added with interferon-γ, and the effect of H2O2 was inhibited by catalase and PDTC. These findings suggest that H2O2 production from LPS-stimulated macrophages participates in the upregulation of iNOS expression via NF-κB activation and that NO is a negative feedback inhibitor of iNOS protein expression.
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We investigated mechanisms underlying death of cultured rat liver sinusoidal endothelial cells exposed to chemical hypoxia with KCN (2.5 mmol/L) to simulate the adenosine triphosphate (ATP) depletion and reductive stress of anoxia. During chemical hypoxia, acidotic pH prevented cell death. Glucose (0.3-10 mmol/L) also prevented cell killing. Cytoprotection by glucose but not acidosis was associated with prevention of ATP depletion. After 4 hours of chemical hypoxia at pH 6.2 (simulated ischemia), rapid cell death occurred when pH was restored to pH 7.4 with or without washout of KCN (simulated reperfusion). This pH-dependent reperfusion injury (pH paradox) was prevented after KCN washout at pH 6.2. Glycine (0.3-3 mmol/L) also prevented the pH paradox, but glucose did not. The initial protection by acidotic pH and glycine during simulated reperfusion was lost when pH was later restored to 7.4 or glycine was subsequently removed. Mitochondria depolarized during chemical hypoxia. After washout of cyanide, mitochondrial membrane potential (delta psi) did not recover in cells that subsequently lost viability. Conversely, those cells that repolarized after cyanide washout did not subsequently lose viability. The actin cytoskeleton and focal adhesions became severely disrupted during chemical hypoxia at both pH 6.2 and 7.4 and did not recover after cyanide washout under any condition. Glucose during chemical hypoxia prevented cytoskeletal disruption. In conclusion, endothelial cell damage during simulated ischemia/reperfusion involves mitochondrial dysfunction, ATP depletion, and ATP-dependent cytoskeletal disruption. Glycine and acidotic pH prevented cell killing after reperfusion but did not reverse mitochondrial injury or the profound disruption to the cytoskeleton.
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Cultured human cells were transfected with cloned rat glycine receptor (GlyR) 48 kd subunit cDNA. In these cells glycine elicited large chloride currents (up to 1.5 nA), which were blocked by nanomolar concentrations of strychnine. However, no corresponding high-affinity binding of [3H]strychnine was detected in membrane preparations of the transfected cells. Analysis by monoclonal antibodies specific for the 48 kd subunit revealed high expression levels of this membrane protein. After solubilization, the 48 kd subunit behaved as a macromolecular complex when analyzed by sucrose density centrifugation. Approximately 50% of the solubilized complex bound specifically to a 2-aminostrychnine affinity column, indicating the existence of low-affinity antagonist binding sites on most of the expressed GlyR protein. Thus, the 48 kd strychnine binding subunit efficiently assembles into high molecular weight complexes, resembling the native spinal cord GlyR. However, formation of functional receptor channels of high affinity for strychnine occurs with low efficiency.
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Kupffer cells, the resident hepatic macrophages, are activated by calcium, but conclusive evidence that they contain voltage-dependent calcium channels has not been presented previously. In this study, the cytosolic free calcium concentration ([Ca2+]i) of cultured Kupffer cells was measured with the fluorescent Ca2+ indicator fura-2. Partial replacement of extracellular Na+ by K+ caused an increase in [Ca2+]i in a concentration-dependent manner (half-maximal effect at 81 mM K+), presumably due to membrane depolarization. At 65 mM K+, where there were minimal changes in [Ca2+]i, addition of the dihydropyridine-type calcium channel agonist BAY K 8644 (1 microM) caused a large increase in [Ca2+]i. Overall, the effect of BAY K 8644 (1 microM) was to shift the concentration-response curve for K+ to the left (half-maximal effect at 61 mM K+). Under depolarizing conditions (65 mM K+), BAY K 8644 increased [Ca2+]i in a concentration-dependent manner (half-maximal effect at approximately 400 nM BAY K 8644). Moreover, the dihydropyridine-type calcium channel blocker nitrendipine inhibited the BAY K 8644-induced increase in [Ca2+]i in a concentration-dependent manner (half-maximal inhibition with about 25 nM nitrendipine). When extracellular Ca2+ was omitted from the incubation medium, the increases in [Ca2+]i due to BAY K 8644 were prevented completely. In addition, an intracellular Ca2+ antagonist, 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate hydrochloride (200 microM), did not inhibit the BAY K 8644-sensitive, voltage-dependent increase in [Ca2+]i. Thus, these data collectively indicate that BAY K 8644 causes a transmembrane Ca2+ influx in Kupffer cells in a voltage-dependent manner, providing the first direct evidence that Kupffer cells contain L-type voltage-dependent Ca2+ channels.
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The transition metal iron is capable of catalyzing redox reactions between biomolecules and oxygen that would not occur if catalytically active iron were not present. Although these biological oxidations (which are known collectively as "oxidative stress") have been implicated in numerous toxicities, the exact role of the iron catalyst remains to be elucidated. This review focuses on our current understanding of the role of iron in oxidative stress, discussing biologically relevant sources, biochemical forms, and reaction mechanisms of iron as a catalyst of biomolecular oxidations. Specific toxicities in which alterations in normal iron metabolism is thought to overwhelm the body's antioxidant defense system are presented, and future treatment regimens involving novel antioxidant drugs are discussed.
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Blockade of phagocytosis and selective elimination of macrophages (m phi s) are generally accepted procedures for gaining knowledge about the function of m phi s in vivo. This study demonstrates that intravenous injection of gadolinium chloride (GdCl3) not only blocks phagocytosis by rat liver m phi s (Kupffer cells) but also selectively eliminates the large m phi s situated in the periportal zone of the liver acinus. Repopulation of m phi s starts at 4 days after injection. During repopulation, m phi s are less vulnerable to GdCl3. When repopulation is complete, the new m phi s show the same vulnerability as the original ones. Splenic m phi s are less vulnerable to GdCl3 because only some of the red pulp m phi s transiently disappear. The white pulp m phi s are not affected. Repopulation occurs sooner than in liver. These results indicate that administration of GdCl3 is a suitable approach to studying the in vivo function of large Kupffer cells.
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Kupffer cells are activated by calcium and release a variety of toxic mediators, including proteases. The purpose of these studies, therefore, was to determine if protease inhibitors and a calcium channel blocker could increase survival time in the rat model of orthotopic liver transplantation. Survival for 30 days was greater than 90% in this model when livers were stored for 1 hr in Ringer's solution (survival conditions)--however, grafts stored for 4 hr in Euro-Collins solution or 8 hr in University of Wisconsin (UW) solution survived postoperatively only 1.2 and 0.7 days, respectively (nonsurvival conditions). When livers were stored for 4 hr in Euro-Collins containing a cocktail of protease inhibitors (leupeptin, pepstatin A, phenylmethylsulfonyl fluoride, 20 ng/ml each; diisopropyl fluorophosphate, 100 microM) and subsequently transplanted, however, survival time was increased significantly to 11.5 days. Inclusion of a calcium channel blocker, nisoldipine (1.4 microM), in the protease inhibitor cocktail increased survival time to 23 days. Actually, nisoldipine alone increased survival time to 25 days. Nisoldipine alone also increased survival time in livers stored for 8 or 16 hr in UW solution to between 15 and 20 days. Serum transaminase levels reached peak values greater than 2400 U/L one day postoperatively in the nonsurvival groups, and liver injury assessed histologically was apparent. Under these conditions, pulmonary infiltration of inflammatory cells was observed in about 60% of the lungs examined and was associated with massive bleeding. Inclusion of the protease cocktail, nisoldipine, or both in the storage solutions decreased maximal SGOT levels and injury to both liver and lung significantly by about 50% postoperatively. Nisoldipine also decreased phagocytosis of carbon particles by the perfused liver 2- to 3-fold following storage under nonsurvival conditions (half-maximal effect = 0.3-0.4 microM nisoldipine). Moreover, nisoldipine improved hepatic microcirculation. It accelerated blood flow into the liver, as indexed by hemoglobin reflectance from the liver surface. These data support the hypothesis that Kupffer cells are activated early in the sequence of events that causes graft failure leading to endothelial cell-mediated alterations in the microcirculation. This work demonstrates clearly that dihydropyridine-type calcium channel blockers such as nisoldipine may be clinically useful in storage solutions for liver prior to transplantation.
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Glycine (50, 100 and 300 mg/kg), administered daily for 10 days in rabbits challenged with typhoid 'H' antigen and sheep erythrocyte antigen, caused dose- dependent reduction of antibody titre. Inhibition of antibody titre observed with 300 mg/kg was comparable to immunosuppression observed with 1 mg/kg betamethasone.
Article
We designed studies to characterize metabolic aspects of the protective effects of glycine and glutathione against hypoxic proximal tubule cell injury b clarifying the relationship between protection and preservation of tubule cell adenosine triphosphate (ATP) and glutathione levels. The tubule preparation was glutatione depleted as isolated although some recovery occurred during incubation at 37 degrees C, and this recovery was enhanced by treatment with glutatione precursors. Increasing the duration of hypoxia from 30 minutes to 60 minutes produced increasingly extensive lethal tubule cell injury that was almost completely prevented, even at the 60-minute duration, by inclusion of either 2 mmol/L glutathione or 2 mmol/L glycine in the tubule incubation medium. Cell ATP levels decreased to the same extent and at the same rate in protected and unprotected hypoxic tubules. Glycine- and glutathione-protected tubules maintained higher cell glutathione levels than unprotected tubules at all durations of hypoxia studied. However, completely eliminating this increment of glutathione with either the gamma-glutamylcysteine synthetase inhibitor, buthionine sulfoximine, or the glutathione reductase inhibitor, 1,3-bis(2-chloroethyl)-1-nitrosourea, did not prevent protection. The data indicate that the striking protection against hypoxic injury to the isolated tubules provided by treatment with glycine or glutathione is independent of preservation of tubule cell ATP and glutathione levels, to the extent that difference of these levels can be discriminated in intact cells with present methods.
Article
Messenger RNAs isolated from adult or newborn rat spinal cord were fractionated in a sucrose gradient. The fractions were injected into Xenopus oocytes to determine their potencies for expression of glycine receptors (GlyRs), which were then examined electrophysiologically. The sedimentation profiles disclosed two classes of GlyR mRNAs, one heavy and the other light. The adult spinal cord was rich in heavy GlyR mRNA, whereas the light GlyR mRNA was more abundant in neonatal spinal cord and in adult cerebral cortex. Glycine receptors encoded by heavy and light mRNAs of adult spinal cord showed some electrophysiological differences. Thus there are two types of GlyRs encoded by mRNAs of different sizes, and the expression of these mRNAs is developmentally regulated. A tissue- and age-dependent distribution of heterogeneous GlyR mRNAs may imply diverse roles of the GlyRs in neuronal function in the central nervous system.
Article
The mechanism of hepatocarcinogenesis caused by peroxisome proliferators (PP) is poorly understood, making it difficult to predict the carcinogenicity of PP to rodents or other species. It has been suggested that the carcinogenic potential of individual PP in rodents is correlated with the degree of PP-induced hepatic peroxisome proliferation. To evaluate this possible correlation, di(2-ethylhexyl)phthalate (DEHP) at 1.2% and [4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio]acetic acid (Wy-14,643) at 0.1% were fed to male F-344 rats for up to 365 days and hepatocytic peroxisome proliferation and DNA replication were measured. All rats fed Wy-14,643 for 365 days had numerous grossly visible nodules in comparison to none in the livers of DEHP-fed or control rats. Despite this difference in the induction of tumors, both DEHP and Wy-14,643 increased the peroxisomal volume density 4- to 6-fold from 8 to 365 days of treatment. Peroxisomal beta-oxidation enzyme activities were increased 8-fold by both DEHP and Wy-14,643 after 18 days. At later time points (77 to 365 days), these enzyme activities were about 25% higher in livers of Wy-14,643- than DEHP-fed rats. DEHP or Wy-14,643 increased absolute liver weights 50 to 75% above controls after 18 to 365 days of feeding. Labeling of hepatocyte nuclei with a single injection of tritiated thymidine revealed a rapid burst in replicative DNA synthesis in both DEHP and Wy-14,643-fed rats, with a return to control levels by 4 days. Additional rats were implanted with 7-day osmotic pumps containing tritiated thymidine. With this more extended method of labeling a 5- to 10-fold increase in replicative DNA synthesis was observed in rats receiving Wy-14,643 for 39 to 365 days as compared to DEHP-fed rats or controls. In conclusion, when performed under conditions similar to the tumorigenicity studies, the degree of peroxisome proliferation correlated poorly with the relative hepatocarcinogenicity of DEHP and Wy-14,643. However, a strong correlation was observed between the relative hepatocarcinogenicity of DEHP and Wy-14,643 and the ability to induce a persistent increase in replicative DNA synthesis. These data emphasize the possible importance of cell replication in the mechanism of PP-induced hepatocarcinogenesis.
Article
Glycine receptors, as detected by glycine-displaceable [3H]strychnine binding, were solubilized from a membrane fraction of rat spinal cord by the non-ionic detergent Triton X-100. The solubilized material retained its high affinity for [3H]strychnine and exhibited the typical pharmacological properties of the membrane-bound glycine receptor. On sucrose density gradients, the solubilized receptor had a sedimentation coefficient of 8.3 +/- 0.4 S. Gel exclusion chromatography on Sepharose 6 B in the presence of phosphatidylcholine gave a Stokes radius of 7.3 +/- 0.3 nm.
Article
The inhibitory glycine receptor is a ligand-gated ion channel protein that occurs in different developmentally regulated isoforms in the mammalian central nervous system. Here, we have analyzed genomic clones covering the coding regions of the murine glycine receptor alpha 1 and alpha 2 subunit genes. Both genes contain eight intronic regions with precisely conserved boundaries. The same structure was also found for seven exons of a third homologous gene, alpha 4, identified during screening. The predicted alpha 4 polypeptide displays very high homology to the alpha 2 subunit. Like the alpha 2 gene, the alpha 4 gene maps to the mouse X chromosome. Our data indicate that the genomic organization of glycine receptor alpha subunit genes is conserved during evolution.
Article
In humans and experimental animals the presence of bacterial lipopolysaccharide (endotoxin, LPS) signals the presence of gram-negative bacteria. Recognition of LPS triggers gene induction by myeloid and nonmyeloid lineage cells. These inducible genes encode proteins that include cytokines, adhesive proteins, and enzymes that produce low molecular weight proinflammatory mediators. Together the products of these inducible genes upregulate host defense systems that participate in eliminating the bacterial infection. Unfortunately, these same mediators contribute to a serious human disease known as septic shock. Considerable progress has been made during the past decade in determining the sources, identities, and sequence of release of these mediators. In contrast, until recently, marked gaps in our knowledge existed regarding the identity of the LPS receptor and intracellular signaling pathways responsible for LPS-induced cell activation. The discovery in 1986 of a plasma protein termed LPS binding protein (LBP) led to the discovery of unanticipated mechanisms of LPS-induced cell activation. CD14 was found as a soluble serum protein or as a glycosylphosphatidylinositol (GPI)-anchored protein of myeloid lineage cells; it now occupies a key role in LPS-induced cell activation as we understand it today. Here we discuss how LBP enables LPS binding to CD14 and how complexes of LPS and soluble or GPI-anchored CD14 participate in cell activation. We also review the evidence supporting a model for a functional LPS receptor of myeloid cells, which is multimeric, comprised of GPI-anchored CD14 and a presently unidentified transmembrane protein that together bind LPS and initiate cell activation via kinase cascades.
Article
Multiple organ dysfunction syndrome (MODS), previously known as multiple organ failure, has emerged as the leading cause of mortality in surgical critical care. It is a syndrome of sequential and progressive organ dysfunction, associated with a sustained, massive inflammatory response that is often preceded by insults such as sepsis, hemorrhagic shock, inflammatory states such as pancreatitis, and tissue injury. Classically, organ involvement occurs in a predictable sequence, initially involving the lung, then the liver, then the gut, and other organs. With four organ system involvement, mortality approaches 100%. Once the process is initiated, MODS often progresses despite eradication of the inciting cause.
Article
Congenital myoclonus is a widespread neurologic disorder characterized by hyperexcitability, muscular spasticity and myoclonus associated with marked reduction in neural glycine binding sites. The recessive mouse mutation spastic (spa) is a prototype of inherited myoclonus. Here we show that defects in the gene encoding the beta-subunit of the glycine receptor (Glrb) underlie spa: Glrb maps to the same region of mouse chromosome 3 as spa, and Glrb mRNA is markedly reduced throughout brains of spa mice, most likely as a result of an insertional mutation of a 7.1 kilobase LINE-1 element within intron 6 of Glrb. These results provide evidence that Glrb is necessary for postsynaptic expression of glycine receptor complexes, and suggest Glrb as a candidate gene for inherited myoclonus in other species.
Article
The neutral amino acid glycine has been demonstrated to prevent cell death in numerous cell types exposed to a variety of toxic insults. Recently, the central nervous system (CNS) glycine antagonist strychnine was demonstrated to bind specifically to the plasma membrane of renal proximal tubules (RPT) and mimic glycine cytoprotection. Further, it has been demonstrated in RPT that glycine and strychnine block chloride influx in the late stages of cell injury. The aim of this study was to determine if the RPT cytoprotective site is related to neuronal glycine receptors. Only antagonists to the CNS strychnine-sensitive glycine receptor (strychnine, brucine), and not antagonists to the glycine modulatory site of the NMDA receptor (DCQX, 7-CKA, HA-966) or the GABAA receptor (bicuculline methiodide, picrotoxin), prevented mitochondrial inhibitor (antimycin A)-induced RPT cell death. Using immunoblot analysis, proteins corresponding to the 58 kDa beta-subunit of the strychnine-sensitive glycine receptor and the associated protein gephyrin were identified in rabbit kidney cortical membrane fractions and RPT. No protein corresponding to the 48 kDa alpha-subunit was identified. Thus, glycine and strychnine may exert their cytoprotective effects via a putative plasma membrane receptor that is related to the strychnine-sensitive glycine receptor found in the CNS.
Article
Homozygotic spasmodic (spd/spd) mice suffer from a motor disorder resembling poisoning by the glycine receptor antagonist strychnine. Here, a point mutation was identified in the glycine receptor alpha 1 subunit gene of the spasmodic mouse which predicts an alanine-to-serine exchange at position 52 of the mature polypeptide. Upon expression in Xenopus laevis oocytes, alpha 1A52S receptor channels displayed reduced responses to glycine, beta-alanine and taurine when compared to recombinant alpha 1 glycine receptors. As glycine receptor content in spinal cord and native molecular weight appeared unaltered, this suggests that the spasmodic phenotype results from an altered neurotransmitter sensitivity of the mutant alpha 1A52S subunit.