人體細(xì)胞和腸道微生物數(shù)量,比例課件

對人體細(xì)胞和微生物數(shù)量的改進(jìn)估計(jì)RonSender1.OriginofprevalentclaimsintheliteratureonthenumberofbacterialcellsInhumans為什么大家會普遍認(rèn)為腸道微生物數(shù)量是人體細(xì)胞的十倍，本文作者對文獻(xiàn)進(jìn)行了追溯，結(jié)果顯示1977年Savage,annu,Rev.Microbiol引用超過一千。而它的計(jì)算基礎(chǔ)是胃腸道容積為1L，腸道微生物濃度為1011/g.2.Distributionofbacteriaindifferenthumanorgans不同部位的微生物數(shù)量相差很大，由上表可知，人體微生物約90%都集中在結(jié)腸。所以作者統(tǒng)計(jì)了不同文獻(xiàn)的結(jié)腸微生物濃度，平均值為0.92*1011/g.3.Concentrationofbacteriainthecolon5.UpdatedinventoryofhumancellsinthebodyWefocusonthesixcelltypesthatwererecentlyidentified(Bianconietal.,2013)tocomprise97%ofthehumancellcount:redbloodcellaccountingfor70%),glialcells(8%),endothelialcells(7%),dermafibroblasts(5%),platelets(4%)andbonemarrowcells(2%).Theother50celltypesaccountfortheremaining3%.5.Updatedinventoryofhumancellsinthebodyglialcells:Thenumberofglialcellswaspreviouslyreportedas3·1012(Bianconietal.,2013)estimateisbaseda10:1ratiobetweenglialllsandneuronsinthebrain.However,arecentanalysis(Azevedoetal.,2009)revisitsthisvalueandafteranalyzingthevariationinbetweenbrainregionsconcludesthattheratioiscloseto1:1.Thestudyconcludesthatthereare8.5·1010glialcells(CV11%)inthebrainandasimilarnumberofneuronsandsoweusethesevalueshere.5.Updatedinventoryofhumancellsinthebodydermalfibroblast:Thenumberofdermalfibroblastwaspreviouslyestimatedtobe1.85·1012(Bianconietal.,2013),basedonmultiplyingthetotalsurfaceareaofthehumanbody(SA=1.85m2(Herman,2007))byanarealdensityofdermalfibroblasts(RandolphandSimon,1998).Thedermisiscomposedoftwomainlayers:papillarydermis(about10%ofthedermisthickness)andreticulardermis(theother90%)(McGrathetal.,2004).2.6?1010cells.5.Updatedinventoryofhumancellsinthebody6.MasscenteredapproachassanitycheckforcellcountForareferencemanmassof70kg,25%isextracellularfluid(Shenetal.,2007),another7%isextra-cellularsolids(Shenetal.,2007),thusweneedtoaccountfor≈47kgofcellmass(includingfat).作者對人體的細(xì)胞數(shù)量進(jìn)行了重新估計(jì)，84%為紅