NormalNormal kidneykidney developmentdevelopmentinin medakamedaka fishfish

FedorovaFedorova SvetlanaSvetlanaLaboratory of Freshwater Fish StocksLaboratory of Freshwater Fish StocksBioscience and Biotechnology CenterBioscience and Biotechnology Center

Nagoya UniversityNagoya University

Part IPart I

General organization of kidneyGeneral organization of kidney

TotalTotal bodybody waterwater equalsequals approximatelyapproximately 60% 60% ofoftotaltotal bodybody weightweight inin youngyoung menmen,, aboutabout 50% 50% inin

youngyoung womenwomen, , andand lessless ininolderolder personspersons. . BabyBaby’’ss totaltotal bodybody waterwater isis betweenbetween

65% 65% andand 75%. 75%. InIn a 70a 70--kg kg manman,, inin goodgood conditionsconditions, , totaltotal bodybody

waterwater equalsequals 42 L42 Litersiters. . Water is always circulate in the body, it transport Water is always circulate in the body, it transport

chemicals and chemicals and ““foodfood”” to every part of our to every part of our organisms and take out the wastes.organisms and take out the wastes.

KidneyKidney: e: eitherither oneone ofof a a pairpair ofof organsorgans, , functioningfunctioning toto maintainmaintain properproper waterwaterandand electrolyteelectrolyte balancebalance, , regulateregulate acidacid--basebase concentrationconcentration, , andand filterfilter thethe bloodblood

ofof metabolicmetabolic wasteswastes, , whichwhich areare thenthen excretedexcreted asas urineurine..

TheThe excretoryexcretory systemssystems ofof vertebratesvertebratesconsistconsist ofof filtrationfiltration unitsunits thatthat allowallowsmallsmall moleculesmolecules fromfrom bloodblood toto passpassoutout intointo thethe urinaryurinary spacespace, , specialispecializzededtransportingtransporting cellscells thatthat selectivelyselectivelyrecoverrecover certaincertain solutessolutes andand returnreturnthemthem toto thethe bloodblood, , andand alsoalso recoverrecoverwaterwater inin manymany speciesspecies, , andand taketake urineurineoutout ofof thethe bodybody. . In humans In humans thethe totaltotal volumevolume ofof bloodbloodfilteredfiltered byby thethe kidneykidney isis aboutabout 180 180 LLitersiters /24 h/24 hoursours. . OnlyOnly aboutabout 1 1 toto 1.5 1.5 LLiteriter isis excretedexcreted asas urineurine ..

Basic Histology: text and atlas

General organization of the human kidneyGeneral organization of the human kidney

CortexCortex-- the outer part of the outer part of kidney, it consists of kidney, it consists of glomeruliglomeruli..MedullaMedulla-- part of kidney, part of kidney, where water and salts where water and salts reabsorptionreabsorption occurs.occurs.UreterUreter -- eithereither ofof a a pairpair ofofthickthick--walledwalled tubestubes thatthatcarrycarry urineurine fromfrom thethekidneykidney toto thethe urinaryurinarybladderbladder

Basic Histology: text and atlas

The functional units of the kidneysThe functional units of the kidneys-- nephronsnephrons, , glomerulusglomerulus, ,

proximal and distal tubulesproximal and distal tubules

NephronNephron--, , thethe functionalfunctional unitsunits ofofkidneykidney. . TheThe nephronnephron consistsconsists ofof threethreemajormajor componentscomponents: : thethe glomerulusglomerulus, , thethe renalrenal tubuletubule, , andand thethe collectingcollectingductduct. . GlomerulusGlomerulus isis responsibleresponsible forfor bloodbloodfiltrationfiltration ..Renal tubules (proximal and distal Renal tubules (proximal and distal tubules) tubules) extendextend fromfrom thethe glomerulusglomerulustoto itsits junctionjunction withwith thethe collectingcollecting ductduct..It It isis linedlined byby a a singlesingle layerlayer ofofepithelialepithelial cellscells thatthat functionfunction ininselectiveselective reabsorptionreabsorption ofof waterwater, , inorganicinorganic ionsions, , andand otherother moleculesmoleculesfromfrom thethe glomerularglomerular filtratefiltrate ..Collecting duct Collecting duct communicatescommunicates withwiththethe exteriorexterior andand servesserves asas thethe exitexitchannelchannel forfor thethe remainingremaining wastewasteproductsproducts. .

Basic Histology: text and atlas

Urea concentrationUrea concentration

Atlas of Kidney Diseases

Renal corpuscle Renal corpuscle -- glomerulusglomerulus

glomerulusglomerulus -- a a smallsmallgroupgroup ofof capillariescapillaries , , covered by special covered by special cells, cells, podocytespodocytes; ; glomeruliglomeruli filterfilter bloodbloodduringduring urineurine formationformation

Basic Histology: text and atlas

PodocytesPodocytes

GlomerularGlomerular capillary capillary is highly fenestrated.is highly fenestrated.Capillary is covered Capillary is covered by by podocytespodocytes ––special cells that have special cells that have many many ““legslegs””. Urea . Urea filtration filtration ocursocursbetween between podocytepodocyte““legslegs””

Basic Histology: text and atlas

Types of kidneys.Types of kidneys.

There are 3 types of kidneys: There are 3 types of kidneys: pronephrospronephros, , mesonephrosmesonephros and and metanephrosmetanephros..ThisThis terminologyterminology cancan bebe confusingconfusing, , butbutyouyou shouldshould bebe ableable toto keepkeep thethe orderorder ofofformationformation straightstraight ifif youyou rememberremember thatthat propromeansmeans ""firstfirst", ", mesmes meansmeans ""intermediateintermediate" " andand metameta meansmeans ""beyondbeyond" " oror ""laterlater". ".

PronephrosPronephros -- most primitive of the three vertebrate kidneys, active in the amost primitive of the three vertebrate kidneys, active in the adults dults of some primitive fish (lampreys and hagfish), the embryos of moof some primitive fish (lampreys and hagfish), the embryos of more advanced re advanced fish, and the larvae of amphibians. It is a paired organ consistfish, and the larvae of amphibians. It is a paired organ consisting of a series of ing of a series of

nephronsnephrons that filter urine.that filter urine.

TneTne zebrafishzebrafish pronephrospronephros. . (A) Diagram ofthe larval pronephros at 72 hours postfertilization.

(B) Special stainig of a 84 hours embryoshows the anatomy of the pronephros. Pt –pronephric tubules, PD – pronephric duct.

Development. 1998. 125(23):4655-67

MesonephrosMesonephros -- permanent kidney of amphibians and most fish, developing permanent kidney of amphibians and most fish, developing

posterior to and replacing the posterior to and replacing the pronephrospronephros of the embryonic and larval stages. It is a of the embryonic and larval stages. It is a

paired organ consisting of a set of paired organ consisting of a set of nephronsnephrons having capsules, that filter blood from having capsules, that filter blood from

the the glomerulusglomerulus and tubules, whose cells reabsorb water and nutrients and secreand tubules, whose cells reabsorb water and nutrients and secrete te

nitrogenous wastes.nitrogenous wastes.

MetanephrosMetanephros -- permanent kidney in reptiles, birds, and mammals, developing by permanent kidney in reptiles, birds, and mammals, developing by

the 10th week in human embryos and replacing the embryonic structhe 10th week in human embryos and replacing the embryonic structure called the ture called the

mesonephrosmesonephros. During their development, mammalians go through all types of . During their development, mammalians go through all types of

kidney: kidney:

pronephrospronephros is generated first, then it degenerated and is generated first, then it degenerated and mesonephrosmesonephros is formed. Only is formed. Only

after that after that metanephrosmetanephros will replaced will replaced mesonephrosmesonephros

Part II: Kidney in Part II: Kidney in medakamedaka fishfish

ModelModel organismsorganisms, , includingincluding thethemedakamedaka, , allowallow forfor experimentalexperimentalanalysisanalysis ofof kidneykidney functionfunction andand thethedetaileddetailed characterizationcharacterization ofof diseasediseaseprocessesprocesses ..

In the In the medakamedaka fish, kidney development progresses from the simple fish, kidney development progresses from the simple pronephrospronephros to the more complex to the more complex mesonephrosmesonephros

PronephrosPronephros in in medakamedaka fish:fish:

InIn medakamedaka, , thethe functionalfunctional pronephrospronephros consistsconsists ofof onlyonly twotwo nephronsnephrons withwith

glomeruliglomeruli fusedfused

MedakaMedaka embryo of 1 day of embryo of 1 day of development. Special staining development. Special staining reveals place of future reveals place of future pronephrospronephros. Photo: R. . Photo: R. Miyamoto.Miyamoto.

22--days old days old medakamedaka embryo. embryo. PronephricPronephric kidney begins to kidney begins to develop on the second day of develop on the second day of embryogenesisembryogenesis... Photo: R. . Photo: R. MiyamotoMiyamoto

MedakaMedaka’’ss pronephrospronephrosPronephrosPronephros is mostly formed is mostly formed on the 4th day of embryo on the 4th day of embryo development, and finally development, and finally formed on the 5th day. formed on the 5th day.

Photo: R. MiyamotoPhoto: R. Miyamoto

MesonephrosMesonephros..First First mesonephricmesonephric glomerulusglomerulusappears approximately on 5th appears approximately on 5th day after fish hatching. day after fish hatching. Photo: R. MiyamotoPhoto: R. Miyamoto

GlomerulogenesisGlomerulogenesis in in medakamedakais continued during is continued during ““babybaby””stage . Photo: R. stage . Photo: R. Miyamoto

Pronephricglomeruli

Mesonephric glomeruli

Fry of 5 days old

Mesonephricglomeruli

Fry of 10 days old

Miyamoto

Kidney in adult Kidney in adult medakamedaka

The normal kidney in adult medaka consists of two parts, which are located separately

Each adult medaka kidney consists of approximately 250 glomeruli, which are uniformly distributed through whole kidney length .3-dimentional reconstruction.

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50

100

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200

250

1 2 3 4 5 months

femalemale

Glomerulogenesis in medaka is continued during fry stage and early adulthood. The most glomeruli had

generated to the age of 3-month old.

Glomeruli size is increased during all fish life

Human kidney diseasesHuman kidney diseases

One of the most common human genetic diseases is polycystic kidneydisease (PKD), which affects 1 in 1000 individuals. Kidney cysts are theresult of grossly expanded kidney tubule transportPolycystic kidney disease (PKD) leads to massive kidney enlargement by the cystic dilation of renal tubules and chronic renal failure.The picture of patient with PKD. It is evident that the morphology of left kidney is grossly abnormal. What is more striking, is the enlarged leftkidney that clearly demonstrates cysts (outlined by arrows) In some cases renal transplantation can save these patients' lives.

MedakaMedaka model of human kidney diseasesmodel of human kidney diseases

AlthoughAlthough simplesimple inin formform, , thethe medakamedaka’’sskidney kidney isis composedcomposed ofof cellcell typestypes thatthat arearetypicaltypical ofof human human kidneyskidneys, , includingincludingfenestratedfenestrated capillarycapillary,, podocytespodocytes,, andandpolarizedpolarized tubulartubular epithelialepithelial cellscells..Model organisms, including the medaka, allow for experimental analysis of kidneyfunction and the detailed characterizationof disease processes

MedakaMedaka polycisticpolycistic kidney diseasekidney diseaseMedaka polycistic mutant (PC) was found as a naturally occurred mutant in 1975. It was collected by Tomita and then maintained in the laboratory. Medaka pc mutant develops a kidney disorder in the mesonephros.External appearance of pc mutant.(A and B) normal. (C and D) pcmutant . (E and F) See-through madaka stock. (G and H) pc see-through medakastock. Arrows indicate the range ofthe cystic kidney. The bar represents5 mm, which is applied to all panels. Abbreviations are: ab, air bladder; b, brain; g, gill; h, heart; i, intestine; k, kidney; l, liver; s, spleen; sp, spinalcord.

Kidney Int. 2005 Jul;68(1):23-34

Normal kidney section

Polycystic kidney section

cysts

Kidney Int. 2005 Jul;68(1):23-34

ConclusionsConclusions

Despite some differences in organ morphology between the human and medaka kidneys, many parallels exist at the cellular and molecular levels that can be exploited to further our understanding of kidney development and disease.The same mechanisms and cell types are used in the development and function of both medaka and human kidneys. Many hereditary kidney diseases are common for medaka fish and humans.The medaka presents a useful model for studies of kidney development and disease.

References:References:

Mochizuki E, Fukuta K, Tada T, Harada T, Watanabe N, Matsuo S, Hashimoto H, Ozato K, Wakamatsu Y. Fish mesonephric model of polycystic kidney disease inmedaka (Oryzias latipes) pc mutant.Kidney Int. 2005 Jul;68(1):23-34 Drummond IA, Majumdar A, Hentschel H, Elger M, Solnica-Krezel L, Schier AF, Neuhauss SC, Stemple DL, Zwartkruis F, Rangini Z, Driever W, Fishman MC. Earlydevelopment of the zebrafish pronephros and analysis of mutations affectingpronephric function.Development. 1998 Dec;125(23):4655-67 Atlas of Kidney Diseases // Edited by Tomas Berl and Joseph V. BonventreFedorova S., Hashimoto H., Ozato K., Wakamatsu Y. Three-dimentionalreconstruction of the adult kidney development and nephrogenesis in Oryzias latipes. CDB Symposium "Origin and Development of the Vertebrate Traits". 2005.( Kobe, Japan, April 11-13)Basic Histology: text and atlas. 10th Edition. McGraw-Hill. 2000