人体细胞和肠道微生物数量,比例课件

对人体细胞和微生物数量的改进估计RonSender1.OriginofprevalentclaimsintheliteratureonthenumberofbacterialcellsInhumans为什么大家会普遍认为肠道微生物数量是人体细胞的十倍，本文作者对文献进行了追溯，结果显示1977年Savage,annu,Rev.Microbiol引用超过一千。而它的计算基础是胃肠道容积为1L，肠道微生物浓度为1011/g.2.Distributionofbacteriaindifferenthumanorgans不同部位的微生物数量相差很大，由上表可知，人体微生物约90%都集中在结肠。所以作者统计了不同文献的结肠微生物浓度，平均值为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).作者对人体的细胞数量进行了重新估计，84%为红