微生態(tài)制劑的研制與應(yīng)用

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微生態(tài)制劑的定義和類型

微生態(tài)制劑是在微生態(tài)學(xué)理論的指導(dǎo)下，調(diào)整生態(tài)失調(diào)（microdysbiosis）保持微生態(tài)平衡（microeubiosis），提高宿主（人、動(dòng)植物）健康水平或增進(jìn)健康佳態(tài)（wellbeing）的生理性活菌制品（微生物）及其代謝產(chǎn)物以及促進(jìn)這些生理菌群生長(zhǎng)繁殖的物質(zhì)制品。目前國(guó)際上已將其分成3個(gè)類型:益生菌（Probiotics）益生元（Prebiotics）合生素（Synbiotics）

益生菌，又稱益生素，是指投入后通過改善宿主腸道菌群生態(tài)平衡而發(fā)揮有益作用，達(dá)到提高宿主（人和動(dòng)物）健康水平和健康佳態(tài)的活菌制劑及其代謝產(chǎn)物。其基本指導(dǎo)思想是用人或動(dòng)物正常生理菌群（normalmicrobiota）的成員，經(jīng)過選種和人工繁殖，通過各種途徑和劑型制成活菌制劑，然后再以投入方式使其回到原來環(huán)境，發(fā)揮自然的生理作用。目前應(yīng)用于人體的益生菌有雙歧桿菌、乳桿菌、腸球菌、大腸桿菌、枯草桿菌、蠟樣芽腸桿菌、地衣芽胞桿菌、丁酸梭菌和酵母菌等。Probioticsaredefinedviablemicroorganisms,sufficientamountsofwhichreachtheintestineinanactivestateandthusexertpositivehealtheffectsProbioticfoods

containlivingprobioticmicroorganismsinanadequatematrixandinsufficientconcentration,sothataftertheiringestion,thepostulatedeffectisobtained,andisbeyondthatofusualnutrientsuppliers.Theterm“probiotics”wascreatedinthe1950susedin1965forlivebacteriaandsporesasanimalfeedsupplementsthatshouldhelplimitingtheuseofantibioticsinanimalhusbandry.Thefirstgenerallyaccepteddefinitionwasgivenin1989:aprobioticis“alivemicrobialfeedsupplementwhichbeneficiallyaffectsthehostanimalbyimprovingitsintestinalmicrobialbalance”.Pharmaceuticalproductswithlivebacteriahavealsobeenonthemarketforalongtime,althoughnotlabeledas“probiotic”,andforyearswithoutasufficientproofofefficiency.HealthClaimsforProbiotics

Compositionandeffectsofprobioticfoodsandtheirdetectionmethodsneedtobeclearlydefined.1.Aprimaryprerequisiteisthatsuchfoodsbehealthyandsafe,andfreeofpathogenicandtoxiceffects.2.Postulatedhealtheffectshavetobeprovenbyclinicalstudiesinhumans.Invitrostudiesandanimalexperimentalanalysesonlygiveindicationstopossiblehealthrelevanteffects.Theymaybeusefulforidentifyingmechanismsofaction,orforthesearchfornewprobiotics.3.Clinicalstudiesshouldfollowclearlydefinedstudygoalsandarandomized,double-blindandplacebocontrolleddesign.Theirresultsshouldbeconfirmedbyindependentresearchteams,anddocumentedinpeerreviewedscientificjournalsandbedocumentedaccordingtotherulesof“goodclinicalpractice”(GCP).4.Asevencloselyrelatedbacteriastrainsofthesamespeciesmayhavedifferentphysiologicaleffects,proofsforhealtheffectsareonlyvalidforthe(probiotic)bacteriastrainwithwhichthestudyhadbeenperformed.

Aprerequisiteforunambiguousstudyresultsarebacteriastrains,clearlydefinedwithmodernmolecularbiologicaldetectionmethods.Astrainallocationbasedonphenotypicalcharacteristicsonlyisgenerallynotsufficient.5.Theextenttowhichtheintakeofprobioticmicroorganismsleadstothedesiredhealtheffectdoesnotonlydependontheirabsolutenumbersintheingestedproduct,butalsoonitscompositionandphysicalstate.Thisalsomeansthat,usingaprobioticbacteriastrainindifferentmatricesortogetherwithdifferentprobioticbacteria,thepostulatedeffectshouldbeidentifiedforeachcombination.6.Theeffectivenessofaprobioticandthereforethelowestconcentrationofprobioticmicroorganismsintheproductfromwhichahealtheffectmaystillbeexpected,dependsonthekindofprobioticmicroorganism,theclaimedeffect,thedurationofapplication,thefoodmatrix,and,lastbutnotleast,thetargetgroup.Often108–109probioticbacteriaperdayarementionedastheminimumamountforprobioticeffects.Aprobioticproductshouldguaranteetheingestionofthatnumberofprobioticmicroorganismsattheendofitsshelflife,whichwasusedinthestudiessubstantiatingitshealtheffect7.Probioticeffectsaretargetspecific.Theeffectofprobioticmicroorganismsonstudyparticipantsmayvarywithage,healthandgender,diet,residenceandenvironment,e.g.ruralorurbanetc.Therearedifferenceswithrespecttomaturityorefficiencyoftheimmunesystemtothepredominantmicrofloraand/ortohygienestandards.Thishastheconsequencethatresultsfromstudiesinchildren/agedsubjects,indiseasedpeopleorfromtheThirdWorldcannotbetransferredwithoutfurtherexaminationtoadults,healthypeopleorpeoplefromindustrializedcountries,respectively.Ontheotherhandthismeans—particularlyinthecaseofsmallexperimentalgroupsand/orasmallnumberofstudies—thatinconsistentresultsdonotnecessarilycastdoubtontheinvestigatedprobioticeffect,butmorelikelyonitstransferabilityfromtheparticipantsofasuccessfulstudytothegeneralpopulation.“morestudiesarenecessarytofindoutwhichsectionofthepopulationmayprofitfromaprobioticandunderwhichconditions”.Selectioncriteria.

?Safeforhumans,i.e.freeofpathogenicandtoxiceffects.?Originfromtheintestinaltractofhealthypersons,assuchmicroorganismsareregardedsafeforhumansandbestadaptedtotheecosystemofthegut.?Tolerancetogastricandbileacidaswellassufficientresistanceagainstdigestiveenzymesenablethesurvivalduringthepassagethroughstomachandupperintestinaltract,andhavehealth-promotingeffectsinthegut.AsthedecreaseinpHoftheingestedfoodinthestomachislowduetothebuffercapacityofthegastricacid,resistanceagainstgastricacidislesscriticalthantoleranceofthebacteriatobileacidanddigestiveenzymesinthesmallbowel.?Detectionofparametersenablinga(positive)influenceontheintestinalfloralikeadhesiontointestinalepithelialcells,survivalandreproducingcapacityinthehumanlargeintestine,orproductionofantimicrobialsubstances.Theeffectsofprobioticsmaybeclassifiedinthreemodesofaction(i)Probioticsmightbeabletomodulatethehost’sdefencesincludingtheinnateaswellastheacquiredimmunesystem.Thismodeofactionismostlikelyimportantforthepreventionandtherapyofinfectiousdiseasesbutalsoforthetreatmentof(chronic)inflammationofthedigestivetractorpartsthereof.Inaddition,thisprobioticactioncouldbeimportantfortheeradicationofneoplastichostcells.(ii)Probioticscanalsohaveadirecteffectonothermicroorganisms,commensaland/orpathogenicones.Thisprincipleisinmanycasesofimportanceforthepreventionandtherapyofinfectionsandrestorationofthemicrobialequilibriuminthegut.(iii)Finally,probioticeffectsmaybebasedonactionsaffectingmicrobialproductsliketoxins,hostproductse.g.bilesaltsandfoodingredients.Suchactionsmayresultininactivationoftoxinsanddetoxificationofhostandfoodcomponentsinthegut.ImmunemodulationProbioticscaninfluencetheimmunesystembyproductslikemetabolites,cellwallcomponentsandDNA.Obviously,immunemodulatoryeffectsmightbeevenachievedwithdeadprobioticbacteriaorjustprobiotics-derivedcomponentslikepeptidoglycanfragmentsorDNA.ProbioticproductsarerecognizedbyhostcellsThemaintargetcellsinthatcontextarethereforegutepithelialandgut-associatedimmunecells.Theinteractionofprobioticswithhost(epithelial)cellsbyadhesionitselfmightalreadytriggerasignallingcascadeleadingtoimmunemodulation.Releaseofsolublefactorscantriggersignallingcascadesinimmunecellsorinepithelialcellswhichsubsequentlyaffectimmunecells.However,probioticandcommensalbacterialadherencetogutepithelialcellsinvivohasnotbeendemonstrated.Rather,suchbacteriaadherejusttoandinvadetheoutermucuslayerbutdonotreachtheepithelialcellsthemselvesTheuptakeandtranscytosisofbacteriaisdonebyM-cells,andpassthemdowntodendriticcells(DCs)inthesubepithelialdomeregion.DirectcontactbetweenprobioticsandhostcellsinthegutoccursbyinternalizationofbacteriabyDCswhicharelocalizedbelowtheepithelialcells(nonM-cells)TeichoicacidofL.plantarumisinvolvedintheanti-inflammatoryactivityofthisprobiotic.TheeffectsobservedwereclearlyTLR-2dependent.However,probioticsarealsoabletoprotecttheintegrityofthemucosalgutbarrieragainstthedestructiveactionofenteropatho-genicEscherichiacoliinaTLR-independentway.Adirectanti-nflammatoryeffectofEcNonhumangutepithelialcells(HCT15)couldonlybedemonstratedforlivebacteriabutwithoutdirectcontact.RatherasecretedfactormediatedthiseffectbysuppressingtheTNFa-inducedIL-8transactivationbyamechanismindependentofNF-kBinhibition

Someprobioticsareabletoaltercytokineproduc-tionbymodulatingcellularsignaltransduction.TheycaneitherblockdegradationoftheinhibitorIkBbyinhibitingtheubiquitinationofthisinhibitor,byinterferingwithproteasomefunctionorinfluencingRelAlocalisationviathereceptorg-dependentsignalcascadewhichinturnisactivatedthroughaperoxisomeproliferatorProbioticFood

FermentedMilkProductswithProbioticProperties-Yogurt-like,solidorliquidmilkproductscontaininglivingprobioticbacteriaarethemostpopularprobioticfoodstuffsProbioticCheeseOtherProbioticFoodandFoodIngredientsAlltheseproductshaveincommonthattheirproductionhasbeendescribedinthescientificorpatentliterature,butthattheyhavenotbeentestedinclinicaltrialsandthattheydidnotstayonthemarketforlong.IceCream,Sweets,VegetableFood,MeatProducts,DriedProbioticProducts,MicroencapsulatedProbiotics

Aprebioticwasfirstdefinedin1995as“anon-digestiblefoodingredientthatbeneficiallyaffectsthehostbyselectivelystimulatingthegrowthand/oractivityofoneoralimitednumberofbacteriainthecolon,andthusimproveshosthealth.”“Aprebioticisaselectivelyfermentedingredientthatallowsspecificchanges,bothinthecompositionand/oractivityinthegastrointestinalmicroflorathatconfersbenefitsuponhostwellbeingandhealth.”Accordingtothisdefinition,candidateprebioticsmustfulfillthefollowingcriteriawhicharetobeprovenbyinvitroand—finally—invivotests:?Non-digestibilityResistancetogastricacid,enzymaticdigestion,andintestinalabsorptionwasdemonstratedinvitroorinvivousinggerm-freeorantibiotictreatedrats,proctocolectomizedindividuals(ileostomypatientsandothermodelsmeasuringrecoveryofundigestedprebioticsinfeces,inthedistalileumorinsmallintestinaleffluent,respectively.?FermentationbytheintestinalmicrobiotaTheprebioticcanbeadmixedtofoodordrinkingwater,andtheanimalswillbesacrificedinpre-definedtimeintervalstocollectandanalyzegastrointestinalcontentsandfeces.Intestinalfermentationinhumanscanbeinvestigatedbymeasuringbreathhydrogenorfecalrecoveryoftheadministeredcarbohydrateafterasingleprebioticmeal.?Selectivestimulationofgrowthandactivityofintestinalbacteria.Theselectivityofthepromotionofmicrobialgrowthandfermentationactivitybyprebioticoligosaccharidesisdifficulttobeprovenbyinvitroex