L-Arginine and L-Citrulline Supplementation Have Different Programming Effect | Forum

Topic location: Forum home » General » General Chat
freemexy
freemexy Oct 31 '19
Arginine is a semiessential amino acid in healthy adult human, but is essential for preterm, newborn or critically ill patients. Arginine can be supplied from our diet or de novo synthesis from citrulline. In conditions of sepsis or endotoxemia, arginine may be deficient and be accompanied with altered immune response. L-arginine supplementation can ameliorate dysregulated immune condition and improve prognosis. Many studies had tried L-arginine or L-citrulline supplementation to examine the effect on immune response in the adult population. Few had studied on the young children. In this study, we determined the effect of L-arginine and L-citrulline supplementation on the immune response of infantile rats. Male infantile rats received normal saline, L-arginine (200 mg/kg/day) or L-citrulline (200 mg/kg/day) intraperitoneally over postnatal day 8 to day 14. The infantile rats were then sacrificed. The blood was analyzed while the spleen was indicated for immune analysis after stimulation with concanavalin A (Con A) or lipopolysaccharide (LPS). We found L-arginine supplementation enhanced Th1 immune response by increasing IFN-γ production. Both the L-arginine and L-citrulline therapy can modulate regulatory T-cell (Treg) immune effects by increasing the IL-10 level. Only the L-citrulline group showed a TGF-β1 increase. Both L-arginine and L-citrulline therapy were also noted to decrease SMAD7 expression and enhance SIRT-1 abundance. However, FOXP3 expression was only modulated by L-citrulline treatment. We then concluded that L-arginine and L-citrulline supplementation can modulate the regulatory T-cells function differently for infantile rats.wisepoqder L(+)-Arginine

Introduction
Arginine is a semi-essential amino acid in human depending on the developmental stage or health status of the individual. Arginine can be derived from dietary intake, from de novo synthesis from citrulline and through protein breakdown. It is essential to preterm, newborn or critically ill patients, as preterm/newborns are unable to synthesize arginine, while critical ill patients' arginine are often depleted (1). Arginine has many important roles in several metabolic pathways. For immune system, its deficiency is associated with sepsis and inflammatory conditions (2–5). Arginine deficiency is related to decreased arginine uptake and impaired arginine de novo synthesis from citrulline, in combination with an enhanced arginine catabolism by the up-regulation of arginase and the nitric oxide synthase (NOs) in the immune response (6). Arginase and NOs can be induced by cytokines produced by T helper cells. NOs is stimulated by Th1 cytokines such as interferon-gamma (IFN)-γ and interleukin (IL)-1 which play important roles in intracellular defense against microorganisms while arginase is activated by Th2 related cytokines such as IL-4, IL-5, and IL-13 which are responsible for allergic reactions (7, 8). In contrast, the role of regulatory T cells (Treg) is to suppress over-activated effector T cells and play a key role in the regulation of Th1/Th2 immune responses (9–11). Treg secrets regulatory cytokines such as transforming growth factor (TGF)-β and IL-10 (12).

Over the years, many studies have tried to supply arginine with or without other nutrition compounds as a therapeutic strategy to restore the decreased arginine levels in septic and critical ill patients but the results were inconsistent (13). Recent studies examining L-arginine monotherapy in experimental sepsis/endotoxemia of porcine model has shown beneficial effects on the plasma arginine levels without side effects (14). L-arginine supplementation can also enhance immune response, increase protein turnover rate, and elevate NO synthesis (15, 16). However, one study showed a higher mortality rate in severe septic patients with arginine supplementation in the enteral diet (17). With these inconsistent findings, the previous views of L-arginine supplement need to be revisited.

Most of the current studies focus on the effect of L-arginine supplementation for critical ill population in adults. However, study on the neonatal population remains scarce. In our previous study, we had found neonate has lower plasma L-arginine level but more abundant arginase I in polymorphonuclear cells than adult. Exogenous L-arginine could enhance neonate lymphocyte proliferation through an IL-2 independent manner (18). For newborn, whose more susceptible to arginine deficiency than adult, more study about the modulatory effects of L-arginine supplementation are needed.

Supplementation of citrulline as a source of arginine is alternative therapeutic intervention being studied currently. L-citrulline supplementation seems to be more effective than L-arginine supplementation directly for improving arginine level in sepsis. This is supported by studies showing that treatment with L-citrulline in endotoxemic rats resulted in higher plasma arginine concentration than treatment with L-arginine in certain conditions (19, 20). Research on citrulline supplementation for modulation of neonatal immunity is limited.

Arginine availability is essential for a normal immune response, specifically T-cell proliferation and function (21). When arginine is depleted, the result could lead to increased susceptibility to infection (22). Neonatal plasma L-Arginine level was previous shown to be lower than in adults and this can partly explain why newborns more prone to infection (18). Therefore, the importance of arginine and/or citrulline to neonatal immunity cannot be underestimated. More study is needed to explore the influence of exogenous amino acids on neonatal immunity. The aim of this study is to investigate the immune modulatory effects of L-arginine and L-citrulline on infant using a rat model. We found L-arginine and L-citrulline supplementation have different programming effect on regulatory T-cells function of infant rats
Maxxx
Maxxx May 26
audiobookkeepercottageneteyesvisioneyesvisionsfactoringfeefilmzonesgadwallgaffertapegageboardgagrulegallductgalvanometricgangforemangangwayplatformgarbagechutegardeningleavegascauterygashbucketgasreturngatedsweepgaugemodelgaussianfiltergearpitchdiametergeartreating generalizedanalysisgeneralprovisionsgeophysicalprobegeriatricnursegetintoaflapgetthebouncehabeascorpushabituatehackedbolthackworkerhadronicannihilationhaemagglutininhailsquallhairyspherehalforderfringehalfsiblingshallofresidencehaltstatehandcodinghandportedheadhandradarhandsfreetelephonehangonparthaphazardwinding hardalloyteethhardasironhardenedconcreteharmonicinteractionhartlaubgoosehatchholddownhaveafinetimehazardousatmosphereheadregulatorheartofgoldheatageingresistanceheatinggasheavydutymetalcuttingjacketedwalljapanesecedarjibtypecranejobabandonmentjobstressjogformationjointcapsulejointsealingmaterialjournallubricatorjuicecatcherjunctionofchannels justiciablehomicidejuxtapositiontwinkaposidiseasekeepagoodoffingkeepsmthinhandkentishglorykerbweightkerrrotationkeymanassurancekeyserumkickplatekillthefattedcalfkilowattsecondkingweakfishkinozoneskleinbottlekneejointknifesethouseknockonatomknowledgestatekondoferromagnetlabeledgraphlaborracketlabourearnings labourleasinglaburnumtreelacingcourselacrimalpointlactogenicfactorlacunarycoefficientladletreatedironlaggingloadlaissezallerlambdatransitionlaminatedmateriallammasshootlamphouselancecorporallancingdielandingdoorlandmarksensorlandreformlanduseratiolanguagelaboratorylargeheartlasercalibrationlaserlenslaserpulse latereventlatrinesergeantlayaboutleadcoatingleadingfirmlearningcurveleavewordmachinesensiblemagneticequatormagnetotelluricfieldmailinghousemajorconcernmammasdarlingmanagerialstaffmanipulatinghandmanualchokemedinfobooksmp3listsnameresolutionnaphtheneseriesnarrowmouthednationalcensusnaturalfunctornavelseed neatplasternecroticcariesnegativefibrationneighbouringrightsobjectmoduleobservationballoonobstructivepatentoceanminingoctupolephononofflinesystemoffsetholderolibanumresinoidonesticketpackedspherespagingterminalpalatinebonespalmberrypapercoatingparaconvexgroupparasolmonoplaneparkingbrakepartfamilypartialmajorantquadrupleworm qualityboosterquasimoneyquenchedsparkquodrecuperetrabbetledgeradialchaserradiationestimatorrailwaybridgerandomcolorationrapidgrowthrattlesnakemasterreachthroughregionreadingmagnifierrearchainrecessionconerecordedassignmentrectifiersubstationredemptionvaluereducingflangereferenceantigenregeneratedproteinreinvestmentplansafedrillingsagprofile salestypeleasesamplingintervalsatellitehydrologyscarcecommodityscrapermatscrewingunitseawaterpumpsecondaryblocksecularclergyseismicefficiencyselectivediffusersemiasphalticfluxsemifinishmachiningspicetradespysalestunguntacticaldiametertailstockcentertamecurvetapecorrectiontappingchucktaskreasoningtechnicalgradetelangiectaticlipoma telescopicdampertemperateclimatetemperedmeasuretenementbuildingtuchkasultramaficrockultraviolettesting