PREVENTION OF CADMIUM INDUCED

)

PREVENTION OF CADMIUM INDUCED

IM~UNOPA1HOLOGY

BYZINC IN. MICE

".

-St..lohn's

BY

."!C>'BadrulAlam'Chowdhury,M,B..B.S.

A thesissubmitted tothe School :of Graduate

/

.Stt1~iesIn partialfulfillmentofthe requirem~I.S_'of lh.Cdegreeof

n

Doctorof'P~ilosophy ~

FaculiY

ot

Medicine Menfotial-Vnivetsity ofNewfoundland'

April1988

Newfoundland

p;rllliaeion has been granted to the National Librafy of 'Ca na d a to ,a i c r o f i l m thh thesis and -t o lend'or lIell co?ies of the film.

""Th e author (copyright owner) has reserv·e,d .ot-'he.r publication rights,',and neither the ·t h e s i s' nor extensive extracts from'it

·'ma y,be printed or otherwise

.reproduced wit.hout hie/her

·wr it t e n permission.

,ISBN

. .

..

L'e.utorfea.tion e. ' t ' a.ecc'rd'e l la Bibl ioth!lque na tiona'le du Canada' de aicrofi,ll1er cet.te t.hbe et.·de-prater au de...ven~e(.deil: e:le';plai~e.du

filO

G '

L'a~ ~ur ~~itulaire,

^dU,

~~~t

d'e.u eur) ee r4 .. erve 1••

autres droit. d. ,publicationl ni:.l a th~.e ni de long.

extrait. de ce11e-ci ne dolvent. Atre.imprim6s',o u autreaentreproduit. eane 80n Il.utorisll.tic:n 6edte.~

O~315-4S089-4

<;admium¥an ubiquitous toxic metal to.w~icheveryone is~~.at low levels..It istoxic10 almostevery organ system of the bodyincl~dins the'immunesystem. In thisstudy..the ef£;ects of a rel~tiv.etylow dose of _.cadmium

o~

^{the immune systerhof.mice"}

~

^the

, ~ffects . 01 .~ .

^moderately.

large

~ose

^of'zinc

on(Cad~ium.induced immunOpalhO!~F~e

^*Idicd.

'SIx~

week oldt:S7BU6 male.m~~wereexposed'-I~SO.ppm~~dmiumJndrinking 'water for 3 weeks,.and.killed 0,'3'an_d 6

we~ks '

^a/lcr-.cessatlon. .

.edrnintstratlorr-vprevented -tbe"enhancement of antlbody-fcrml

~S'ponse. p~olir~iatiye · re~ponse,

^'of

SP1~en~:E

^{to'the-T' CCI\ ltogens:}

'phytohaemagglutinin_and concanavalinA tend: to be high'

F

^cad

iil~

•treated, mice'

an~' zi~c '

administration after, sure to

cad~ium

^{tended to.(}

lower it.'Thenumber,of CJ;>g+ cells int~espleen waslowerand the ratio of CD4+ to'CDS+cells,"'refleciing'th~'^,baiance.of.lmmuncreguletory T lymphocytes, was higher·in cadmium treated mice., Concurrent zinc adrOi~istratiori' prevented,the..alteration of,'T'cell subsets•.Suppressor cell ,aetivity-

t~n~~ _'

^{to be}

~~o.w.~

^in;cadmium

tre~t~:... .~i~

^•..

-Natural.Id~ler _~II '

activity'in.the spleenwaslowin'cadmium'treated mice.and ,concurrent zinc treatment'prevented the suppression.B:cell

co~nt ,

^In'_the

antibody.'-prOduction" by splenic Iymphocyte~

,:,:

··i....'."

iii" ~ p:--~

.timulatlonwas not altered·bycadmiumor zinctreatment.Cadmium and

'Il~DEXINGKEY WORDS: cadmium, zinc, collularimmunity

"

v,

Iv

ACKNOWLEDGEMENTS

I express'mydeep sense of gratitude to Dr. R.K. ch;ndra for

~ding

^{me the'oppor:t.unity-to'worki..}

~

this project-and

gi~ng

.;" 0- his_ \

'wise council, encouragement - and supPort"Qri,countless octaslo~s. Dr. .

Chancrehashe;n ex";edlngly

gener~u"

^.rithhi,\me,

an,~,h~ uns~ed'~; ", !

questions and arguments with patience, court'F~.',nd unraifi~g ',a,cod: humour.Dr:Chandra'sadvice andcritical cominentsformedB'veiy''useful {'art,of my'training.Than~-also_to'Of.J.K.Friel-andDr. K.M.Kutty for (.being availabl~ for discussionwheneverrct9~I{cd:._1can.never.rOi'~et- thoit readiness at

a Ir ,

times

to.

discuss problems,"anei provide,'encouraging

cotrnP~ntS~

^{I owe .8}veryt specal

int~lIectuBI ·debt.-to ~th · of _ them. ⁱ

^am'

_ _ _ _ - <>Ial,se-,-gratefttl-to:--Br;--R;F;----Borgman ofClemson-University,SouthCarollna:

for.

ini~iation

^{ofaproject oncadmium}

j mm~I'!~~OrlCitY

^{duringhissabbatiCal}

leave spent with.Dr.Ch~n~raat..Memorial Unive~i~yr-hich ~~bsequentl'y le.d.to this project and .for.'his,.he.lpfulsuggestions subsequently. Thanks . also to Dr.

c:.

Charles ~e of the..Department of MathematlClBnd Statistics of Memorial Unlversity' for .helping me with-It.atisti.cal methodol~iiesand'broadeningmy knowledge onsta~istical^concepts.

!'

'hank

th~,

Newfnundland

~ng" "'s~,, ' Fa'Ulty

^nf

Medicine~esearchand,Development Committee for'funding,thiJpr~Je(:t.

Needlessto saythat~myparticipationin this workwould 0.01have,been possible

witho~t,

^t.he,

fin~,~~ial

support which d,elped m,e'.10'.go

~hrou~ th~

graduate program-.'Fellowship.:support-was generously provided by the

Sc:h~~

_t' ^{of G-raau}_{, '}^{ate Studiesof the'}

Me~orlal

^{Unlvcrsi'tyof}

N~wfoundIBndt _

..

~~.

"-

andsupplemental financialaid was providedthroughthegrarits,-Qf Dr.R.IC.

. . > •

Chandra'andfrom the Facu ltyofMedicine asBursary support..

.,' . . . t

I also expressm~ ~ppreciationand.thankstothe members:and.staff

or

the MedicalAudio-VisualService, Department of Electron Microscopyand

.

,

.

^'

.~Department of Anatomy for cooperation-atvanousstagesof the project.I

"'~Jso ~nk

^all

~mbc'~

^or',

the .,~~un6io'gy

^group.fC?f

~aving'

^me

h~re

^and

allOwIng'me to:work'in this (sliilily.,My,specialthanks to Mr.Bing Au, who ~nt long,hours in'introducingme to various laboratory.techniques - and It.':l:nd.ing~

my

.sid~'whene~errequir~d;:

<' . ' Finally,I expressmy thanks

t o '

^my,wife Dr.Ma"riumParveenfqrthe

unden~~ing

and,

mo~1

support she has

sh~ ~uring

the''courseof'my .•graduate,work.

j UBLICATIO NS

..~vi

Much ofth~_~ork pres~ntjd_~n t~isthesishasbeenpublished or submitted forpublication.Thesepapersare : ,

'~I

' ' ,

\ ' I , " . " ' ' - - .

1. .~owdbury\BA,.Ch~nldra.RK..Trace Elen:entRe~ulation.of Im...munlty

~ndlnfectiO,\In:BranskiJ?,Dinari G, Rozen P, Walker-Smlth.JA,eds.

Pediatric

Gas..troenterh~ogy, .

^{Aspects of} immunology.and irtfectlons.

" ,, ) . ' '"

Front Gast~ln~st.Re~. Vol.13, pp.134-)47, Karger Publication, Basel,

Switzerland,1986\

t

^,r'

_'~

2 Chovidhury'~BA,ChandraR.K.Nutrition, Immunity andResistance tc".-

. ' . -\.1 .: .

Infection. In:~e~eYJ~land,ed.1986 A'Year InNutrilionalMediCine;

.:::,edn. PP,59-84" ~I'^U,' PUbliS~ing" ^{New Cannan,}co~~ecticut~^US,A.,

:. _ J

3. ChowdhuryBA,..Chatd;a RIC.'BiologiCaland Health Impljcatiens of' Toxic Heavy Metal

rd\\Esscn~iar

^{·I race EJement.}Interactions, Prog

F;

^Nu"::

1 987:1 \

:57.113"

4. Chowdhury BA,Friel,JK,~~ndra RK.Cadmlum,.induud rm.mun~p--., ethology isPrevented\by Zinc\~dmlnislration.in Mice.J Nutr1987;

117:1788-1794, .

\

1\ vii

S~

^{Chowdhury BA, Friel'IK.'Chandra RK..}Cadmium-induced Immunop-

~athol_ogy

^..is,

Pr~

^by

~c Ad~inistration i~

^{Mice.Abstract. Proe}

eon

Fed

Bini

Soc'1986;29:103.

. '6. ~~dhUry BA,.Chandra RK. Alter:alion

Dli ..

^Immune.F~ncti~~ in Cigarette.Smokers is Corrected byZinc Therapy.Abstract. J,AIDCol

~nlr

^{1987;6:44£ · .'}

. 1

. I ',

7...Chowdbary_SA,Chan~r~:~K.,~et~1 ~m~undsan~ Immun~\OxiCOlogy._' E(fects and ImmunotOxicd1ogical Biomonitoring,-In:Ernest Merian, ed.·

.".-4 MetAls and-;n-elr

ib~poundl

^{In the}

~D,Ylronment.

Oecurrenee,

An"a~~IS,

.-ndBiological Relevance.-VeH verlagsgesellschaff Weinheim; Federal Republidof

GeF~~' (SUb~itted.

^'1988).

.~

B. Ch~dhury SA, Chandra RIC.'~ffett...of Zinc Administration c8d~ium.induced Suppression of Natural-killer Cell Activity-in Mice.-

(Submitted;1988),

»: '

'!'t-. '#

I

"

...

l

j "

yiii

ABSTRACT •r-, ACKNOWLEDGEMENTs PUBUCATIONS, TABLEOF CONTENTS ,

vi

xiii

1:.

¹⁰

12' 19,

1

²

24

, \

25 29 29 31 33

: ~ ,

, ...

Interactions betweencadmium and zinc 1.1.

1.2.4. Effect of cadmiumon immuneresponses Zinc-an essential trace element

1.3.1.,

~O~gical run~ti.9ns

^ofzinc 1.3.2.' Zin,cand irylmunity • .

•Metallothlonein •

1.4.1. Physiologyand biochemistry of metallothion ein 1.4.2. Role of metallorhlonetn inmetalmetebolsrn. 1.2.

~, 'UST OFTABLES "

l ,

UST"OFFIGURES .. /. .

- /

USTOI1 ABBREVIATIONS':

,

' " ,

/

""

- ~ I' uriR~UCTIO~

Trace elements

!

.' . . .

Cadmiu~

^-a toxic heavy metal 1l2.1/ Sourceof

Cad~i:~ e~posure

1.2::1.. Metabolism'ofcadmi~m ^.'

/

-

.2.3. Toxic'effects of cadmium

.'

·3.

· 3.

·37.

•37

~...^;

43 ,43 44 44

45' 45 46

..\~.... 48

48 48

"

,

49

'50 .50

~O 51

...

Se~ndary^objectives

"," ''/

/

"Obl~ct~s

2.2.1. P~maryobjectives

. ,

Killing-of miceandc.ollectionoftis~u'es. LYmphocyte~,!fltsin'bl00d"thymu~"and"spleen .l.3.i.'·

~ym'ph.oCYte

count in-b109d,."

. :~

4.3.2. Isolation and

'cQU~t ~~:~i:~£, ~~~.es

^..

4 . 3 . t

^Isolation

~nd

^count

of,;~fe~;~ j~es

D!rect

an~' indi!ect

^splenic

PlaqUe-romrin~" ~J1 r~sponS6

4.4.1. . -ImmunIZationof mice 4.4.2.

Prepar~tion

_"0':"^,of.spleen_",~

cel~

_.

4.4.3: Prepar.alion:~or sh~~p.'red-bl~.'cel!solution ,'2.2.2.

2.2.

3.3. .Timeframe .

3.1,

CHAJ'TER4,~JITI[ODS^. 4.1. .Houslng andfee~ing

of

mice'

Experiment4 . be'l

\ IIAPTER2,AATIONALE

~D O BJECIlVES.

21. Retlonale

'3.2.

4.4.

~~4.2.. 4.3..

, .'"

' f'

~

CHAPTER 3. DESIGN

' /

OF THE STUDY

^.

. Etperil~C(htal\ groupsand treatment schedules

Setir"

~hexperim~nls

;" \ . "

,/"'"3;1.1,' Experiment1 S-:~3.2.2. Experiment2 3.2.3.' Experimen t3

,I '

' ,..J

I

~

..

^"

J

I: . )

4.4.4, Absorptionq[gUi~ea~pigcomplement ands"ntl-mQuse-lgGS1

'4.4.5. A$sayfor

~M 8'ntibod~ ~?iming

^{cells " ... .}

52 '

•4.4.6. Assay forlaG arfbodY'formingcells....,. 52

.

. ' . .

In.vitro stimulationofspl.ee~cells withmi~ogens

4.5.

.'.~.:

55 55 56.

57

·57

. ,

58⁵⁹

59 60 60 60 6k 61 64

64 ^'.~

64

6:8 (.

.

⁶⁸

68

-

." 68, 70 '--:' 4.5.1. Preparationof 'spleen cells

4.S~~ .Mitogen,:itim"ula,tion .. ..

Ass~y^ofsuppressor

cell

^ectiviry,

4.~.1 . Activatia~ of-s~ppre~sor ~IIS

4.6.2.-RespOndc!cells".

Pokeweedmitogenstimulated JgG productlou 4.8.3. Chromium release assay

4.9.1.-•.

~

Pokeweed mitogen

siimul~tion

^of

lY.JTIP~1S

·4.9.2.

~e.Jinked i,,:mu~~'Orbenl

^{assay . .}

.Autolmmure

'~ponse

^{in kidney . . . . .}

.

.

^" \

4.10.1. Preparation of kidney sections 4.10.

4.9.

4.10.2 Staining and

exa~inatiOli~

^{ofthesections..}

4.;1~

^.....

E1ec.tron"~'ic~l~r~

^{kidney' " . '}

4.12.. Tracee'eme~0alysil ^.' 4.6.

4.6.1. Suppressor cell,activity

"4.7:

'E~ume'ration ~f

B lymphocytesandTlymphocyte subsets in spleen

4.7.1. .Directimmunofluorescencestaining- 4;7.2. Inditectimmun~fluoresCencesiaining Naturalk:i1I~rcella~l~ty

·i.&l. Preparation of~ple~ic{'lymphocytes

4.8.2: Labelling'of-tat'getceils . .

.. .

;

. .

xi 4.13. Data handling and statisticalana lysis

CIIAPTER 5.RESULTS . s. i . Experiment 1

5.1.1. Generalhealthofmice 5.1.2. WeightOf,different organs

5.1.3. L~phocyt~..countsinblood,thymus and spleen

I 5.1.4. Direct plaque-formingcellresponse 5.1.5. Proliferativeresponseofspleen cells s.I:6. Autoimmuneresponsein k.idneys.

5.1.7. Electron-mi.croscopy of kidney 5.1.8.

,T~su;

cadmiumconcentrencn 5.2. Experiment2

S.2J . General.healthof mice . 5.2.2. Weight

and

IyTilpha;.cyte·counts in spleen 5.2.3. Indirectpleque-Icrmingcell response 5.3. Experiment3

5.3.1; General health of mice

,

5.3.2. . Weightand lymphocytecounts in spleen 5.3.3. T Iyrt1phocytesubsets in spleen 5.3.4. Suppressorcell'activity' 5.4; Experiment4

S 'll .

^Generalhealth of"mice • • • ', • S.

i. ..

welgh,t.IymPhOC)'t,e

a~~ ,B

^,cell;", n" in,spleen 5.4.. Natural killercell8etMty • \~'. .' .,.5.4.4; Pokeweed mitogen stimulated,lgGprOduction'

,:,.

71

72 72 72 7S 7S 83 83

} 86 86

ss

92 92 92 96 96 96 99 99 102 102 102 lOS IDS .109

xii

5.4.5, Uv~rtrace elementlevels 109

REFERENCES • CHAPTER 6.DISCUSSION .

Effectof cadmiumand~ncon kidneys Traceelementlevelsin liver " and kidneys

149 113 114 121 124 126 127 12~

130

"

^.134

147._ ...

tion "theobserveucn s

apyonimmunityamongsmoke rs '.•

Healthi Effectof-ri n

Su m mary and cpneluding_rem arks

~

Effectof cadmiumon immune responses Possiblemechanismsofcadmium immuno trndcity Effect.of' zinc'oncadmium-Inducedimmu nopathology

;Possiblemechanismsofcad mium-zinc interaction 6.1.

6.2.

6.3.

6.4.

65.

6.6.

\ 6.7-.

6.8.

69.

.: "

. .

^'

..

,

.,;.",'.:':; ..:.•.,"~,.;','::~ ::_~..._.::~!.,'..;.~ :.,;....r.........t,

f

r·./

r

xiii

LIST OF TABLES

1.1 Toxic Effects or Cadmium

J

¹³

4.1 Constituentsof Diel 47

4.2 ConstituentsofCulturc welJsinPlaquc-assay 53 4.3 Constitucnts or Culture wellsin Natural-killer CellAssay 63

J 5.1 Weight or Mice 73

5.2 Food Disappe arance; 74

5.3 Weight'or Liver • 76

5,4 Weig~t'or iadl;leys 77

5.5 Weightor Th)'Ruis 78

5.6 Weight of~pleen 79

5.7 Lymphocrtc'Countsin'BI~ 80

5.8 LymphocyteCountsinThymw 81

5.9 Lymph~eCounts in~pleen 82

5.10 Direct Plaque -r0f'!!'ing

Cell

Response

as

5.11 ProlirerativcResponse

or _~

⁸⁷

5.12 Cadmium Concentr8tioninthe Kidneys 90

5.13 CadmiumConceniration intheUver. 91

5.14 Weight of Mice 93

5.15 Food Disappearance.' 94

5.16 Weight and Lymphocyte Countsin Spleen'. 95

5.17 Indirect Pleque-fcrmlngCell Response 98

5.18 Weight of MIceand FoodDisap~rance 100

5.19 W~ightand LymphocyteCount"~Spleen 101

.. .-

;~:/;).;;';~~jur

^..

i~),;·:, . ':'~:. '".:

^.i'.:!.•

,;,}~",,"

^....._•

..:.-~:.~

^:..

~~,

^....

-~'.:-..:,::::

. )

dv

~.22 5.20

~.23 5.21

103 106 107

li'o

111 137

. 1~9~, . ,

14(>

." V

141 .J

6.1 Characteristics of the Study Population 6.2 Circulating Lymphocyte Profile

\.

6.3\.. Serum Upid Profile • 6.4 Trace ElementLevels in-Plasma

T·lymphocytcS~bsel5in the Spleen at 0 week Weight of Mice and Food Disappearance . Weighlo\LymPhocytean~.BCell.Count in Spleen Afllibody ProductionbyPokeweed-mitogenStimulated

Lymphocytes

r

5.24 Trace Element Concentrations in Liver at 0 week

.

''',.':-, ''

3.1 4.1 4.2 5.1

') L~ST OF FIGURES

Designof theExperi~ent

Haemolytic Plaques wi,th Antibody Producing Cells St~ndardCurve for ELISA.

IgMPlaques

40 54 67 84 5.2 ElectronMicroscopyof KidneySections

5.3 -IgO

P~.ques

^{- . •' \ . . . .}

""r." .

6.2, ;'Lymphocytc'Transformation Responseto'Concanavalin A 6.3 - Natural-Jdller

~.I!

^Activity

·I·~.

5.4 5.S

.6.1

~uppreuor

Cell AClivi'! .' . . . "

L ' .

Natural·killer Cell"Activity", ," . .e., , ', ' •

Lympliocyte

Tr~nsfonnation 'Respo!1se

^to

Phtoh~e

'gglu.tinin 104 108 142 143 144

(\

\ cadmium

cluster of differentiation Celsius

balanced saltsolution

cerbon-dioxtde concanavalinA chromium

",'0:

(

.

complement cholesterol

gum

I

high-densityIiP

o

^p

r O l l' . .

immunoglobulin kelvin kilogram

:::::~:

_nanogram

7::0,:,~~o/ romPI~x

natural-killer

-

^\

.

'.,i:.,. ,. • ". . d'i:. .." ":. . ..,, ^{.:c ,:,,;:,;,' ..•.• ;,} .;':;'·"<-;·"""·

copper

\= _ cysteine

enzyme-linkedi~munosorbeiltassay fluoresceinisothiocYanate'

LIST OF ABBREVIATIONS

BSS 'C C

"

Chi Cd

~': y CD

Cr

:.~-

, _~

ConA Cu

...

Cys

. .

ELISA FITC g HDL

19 /

K Kg LDL mg MHC ng NK

PBS PBS-T PFC PHA

SCA SRBC

xvii

phosphate-buffered saline phO!iPh~le-YUffercdsaline-Tween2~

pJ.aque.for ing cells c~o~aemagglutinin

RosewellPark .Memorial Institute suppressorcellactivity~

sheep red blood cells

CHAPTER 1

1',',

INTRODUCfION

--..

1.1.TRACE ELEMENTS

The bulk of living matter consists· of fiv

.

e elements,namely, carbon,

^.

hYdrogen, nitrogen; oxygen,and'sul~r. They'are present in tissues-in

·concentrauons':of grams per kilogr~mand theiraduU human require~en,ls

·are in the,range of,gr~msper dlty.!heinacrominer~ls's~iu~,potassium,

~lcium, magnesium, chlorine and 'phosphorus ;serve _as" ·structural

~~~!1e~~

^__

o~ ti~!J~

^or

~ co~stituenls t.Pf

^{-,Ihlt·body.}

..,,....~"'"'._~.c...,..;

co'nc!ntrationin living, tissue and adulthu~anrequirements are somewhat lower than the bulkelem~nts,·but still canbeexpressed as grams per. kilogr~m'and grams'or fractions of a'gram.per.day.The bulk'elements and macromin~ra1s arc essential for the functiono~all. cells and the organism.;»

·'as a ~hole. The remaining e1cme~ls of the: periodl~ table-that'~u.~

naturallyinth~ living·tlssues are,-present in much lower cqnceniratlons.

Earlier analyt~cal.. methods were unable.. to determine their precise concentration, hence they,were of~n.described as.~rr}ng^'in "traCCl;~

and.

yg .

tenn "trace.element"arose,to tknote them. Although present-dey

·techniques"can.virtuaity estimate all'elements in biological rnatc;rial'.wl~

·~cat a~l1racy, the.term'."tra~'element" is ~UII,retained'In Ilte~ature largely-because it,~ hall~dbytime and tradition. Nevertheless the tenn docs provi~ a descriptive-:,classi~cation for a group of elemenbwhOle

"\c

c.,~

'/:'.1

..

^~"

.

^'

~':','

very,maD and expressed in terms of milligrams ormicrogr&mJper

~m

^(Mertz,1981;Mcrtz. 1986).

hormones,cobaltls.theessential metal.in'.vitaminB,J2~chromiumacts'as a cofactor Cor'f~uliR.'eine.is,an essentia l roCactor.in ma ny.metalloenzymes. andcopperb,a

key

regulatorofIysyloxidaSeactivity.,~I'raceelements ere ,:requJrcd'in..'an

' opti~um

^levelfo; their'.function.

, Deficien~

^{will,resultin;}

, pie, iron is.an.essential''compo~ent.~r the.oxygen ~ng..protein .( haemoglobin,. i.odine is essential for,-CunctloI!aJ, activ,ity .of thyroid T~c1cments. which include all thc naturally ~g'elements o:~pt th~ bu~ element and Duu;rominuals.canbe classified into ~ CategOries:,6nt..~

'''':i?

proven_esscnt~ity; second,~ose for which

'p~oofof-essentiality'.does··net cxist_(1'4ertz, J986).The'essentialityof a

tr~ce el~~nt

^,.b-·.

jUdg~d

^{by-,.the cn,tenon 'that its}

def1ciet.t,.J~ntak~

-con!~tently.resulu:In' imPainn.ent of a function-which is'prevented or, corrected.by

IUPPle~en!-Btioh ~th , ph~iological. ~eve~~

^{of the-particular,}

element and not

bi· ·

others.,By.th is criterion chromium",cobalt. copper,

. ' ~, : .. "

.

^" " '., . "

'"'

^,

f1~orine,.iodin~•.•iron. man~anese, ~~Jybdfnum, selenium and zinc\are . . .accepted"asessentialat present, even.thau~

a ll

^ofthese donot'presenta r>.,_- practical'-nutritional prob lem to

hu~ans.~~- additi~n,

^'arsenic,

: niCk~~

.,ilioon, tin.

~

vanadium are often included

in

^{the esse}

nti~

^trace

el~meni

^.

groupas

~~fid;;;q,

^{Symp toms---.h8,!O}

~rel1

^{bunreponedfor.them.but'the\.}

...,ite.,ndinodeof eeticn of

ti.':~';e~no;

..ytt clearly defined .

•

(Me~

^;981;

Menz,I986~ .

^{. ..}

- ~' .

^{\ '.'}

.

^{. ' .}

_~

Most, ~f ^{the eisential.tra ce}'ele ments"

act '

pri~anly ^as s~ctural ^{.\ . .-} components.or catalYsts in large molecules,hormones!

~'nd

^{enzymes.'Fo; \}

\ .

~ "

. ... .

'··~:;".:~t.

^'"..

~·~.v.~~~i·~:~~:~,.~i>oi:~i;) '(;i~~:.,.

,I",,;,b...i.'.::-

~

^-.:..""

":":";,:;,.~""

^{•., ••}

,;".~~'~

^....,,,.,...

~,.;

:;.i.•:....,.;;:

..~

c

suooPt~mal funct~isea~ \~d

^{inextreme death"Similarly,'excess}

intak~will cause toxicity and\can have a'fatal outcome.All essential trace elements thus have a bell-Shaped dose response curve, the kurtosisof which varies.For some, like\selenium, difference between optimum tissue' level !U'd'toxic level isver;. nerrcw; while for othert,'like zinc.it'is \ _

. . I '

relative~.r~' In tihebio~ogicalsystem\,"Optimum concen~~tio.ns of. trace elements are·'.,-.

main~ained by\ _~.series '..p~ regulato~ .~echanlsms

^like

absorption,.distribution, metabolism and'etcr~tlon.

Some

proteins are.also involved'm the.·m

eta~U;in Ji

^trace

elemeo~; "Uk~

transferrin forlroo, ceruloplasmin for

~.p~i, .:.~nd.\ metall~~IOn~in

',"for-

h~a~ '

^{tetalS.cadmium,}

zinc,.copper and~.thers~.".Althor~h t~efunction of allth~se prot,elns'are'.

.~otprecisely~own,mosta~~\as\carriers orb~ffersaglli(lsJ excess, Among the'second grouplof trace elements, for which no css ntiel function

has~~n

^described

i~" ran,

^{some areof}importance due't their prm:~O'toxicities. Lead,.cadmiu1'and mercury are Important examples'of tl).isgroup,.A lthoughall tr.ace'!e~ei~ts,.incl,udingjhe essential ,elemen~,_ have inherent properties of toxiC,itt:ovhen..present inexcess; lead, cadmium and

,, ~erCury

^serve"

n~

^.

eSsentia~ 1~IOgi~I ' f~nction,

^{.they are'}·eumula'tlve !"l

"poisons and~re.,^toxic'ever .!It\low··do.~es. ^Their p.~ma~ .^Importanceto biologists'is due to Illeir toxicity. Ideally none of these.toxle metaIJ shouldbepresentinthe~iSSUes.:but due tovindustrial activity a1id'human

'I habits,' all.,orga.nismsare, C4?ns~ntly,exposed-,....,to these .elemeats,and

\accumulate a.ccraidereble amount:0 ['them in't~e tissues, Toxic,heavY

\me tals arc brought up from the,'e'ai1h'scrust for

i~d~strlal

^';'Ieand uioolly

\ . .

^•..

ve~,little ofI~em arc recycled. :l;hust~eJr lev,eJ In,:the ~nvfroilJ~entiJ

grad~,In~ea.tng, also are the, levell In human'and animal;tiHue.

;1' . _•

(Na tionalAcademyorSciences, 197 8).

This

isparticularly true forlead and

I

~dmi~m.

^{··TIle.potent ial}

toxiciti~ s > ^1~1s

^{ofthese·. e nts to'which -}

the general population,ia inadvert,rltly espesed

~

^{thus of} considerable/

.. - - . ' !

PUblic...healthImportance. ' . /

Among many functions of tra ce clements, recent studies have also

dem~mst~ed

their importa nce in.the

~egulatlon or immu~c Jun~,~ns

^ind

host detensemechanisms.Th.~.irnpetus to.the st~dYof trace element! and i,~m\lnitywasgen erat e d from stud iesdemonsir atlng ~~~stent.Impairmen t-

.·" :1"

" ,I

I

i I

: ( . ;' ~drl .an~,: Dayt~\:l.~),.~-' H~r~_.'.1n . "m~i ,·.-or ^"

i,' ' ; Immunol~ty,

^•

~"I h:~ ' .

" " 0' .he

r

^{rente,roJ,.mode of}

:",mm~"'tI<>?

i:::,

,h :

_~~>'

^;"

"" ;L..:\,:" .:",JL.",;.~,~.:,.,;,, • ." , .. \,~_ '~' ~>',IO.",,,,,"i.: ' -" i~

'J

d f ^{; t .}

^{~i'i~uQe functions'inchildre n ~uffering from gross'}undernu trn io n, like

f i

proteln-energy malnutritIOn, in ~hiCh" ^{not 6DIy-'sup ply.}ofprotei~.;;;"~'

~.:. tlll~ries^are.defiden~biltalsO,bodysto res-cr most vitaminsand ~ntial. ^.

~~:~.

^{trace elemene are leu than''adequate (Chandra. 1972;'-}

Otowdh~ry ~~ .

> ~ , . Cband~

^{Ch.nd"1988), . ' '-}

~

^{'" The}...!,opK:\t...trace clements and

imni~nity ~

^{been'"the subJect of}

. ^{. . " .,}

^'

~~. . seve~1workshops.'reviews_andm~~phs(Olaoon. and Dayto n, 1982; "

1_ . Beise~1982i Olowdhuf)'Bnd_Chand ra, 1986b, Chandra,1987). !he esscntml t~; ^{trace.elements,} p~CUlarJ). ZinC. _{~n, '}coppCr and_,sele~ium ^arc'now {~. eitablls hed critical{actors'in the generation.maintena nceandarr(pliflC8.tion

~:.: ^or.Immune :~.po~

'.

D'efic~eneles o~.thC~..'elements_r~duces^_the ~Ilular

.~~ Imm une function'.both Inman an d labo ratory':a,nlmals and-Increases. the v, suscept ibility'10

'infe~tlon

^{"and other"}

Im~unOI~g1callY:"

^{mediated'd iseasC5.'}

," Among.the

non-e!.\en~I~I,

^trace

~et8ls",j' 1C8~ ' Cadmlu~ "

^{and mer cury}

h~~e .

- ~"'-'

been shown to be Immuno toxic in experime ntal animals (Kolle r, 1980;

has been used which is of relatively little significanceto possible huma n toxiclty.,.yevenheless., these studies show that toxic met als also affect

...:".:0' I

immun~ponsesthat are of potential health significance. '

,~~

Oneimportant aspect that has emerged from recent

. ^.

stuF!les on trace^. el~men~ is the existence~"Interactlons among them.·Trace elemen ts interact,between themse lves a\d a.lso withother dietary eleme n ~s. The", topic hJ"beenreviewed recen tly,'(TheTa.sk.Group on MetalInte ractjo n, 19~8j Levander)~nd 'Che ng, 1980; .AbdUlla,.Nair'8n~ Cha~dra, 1985j·.· "

Ch~dhUry~.Cha~drs" ^1981). However 'the effects..snd impli~ionll of~ this phenome non on immune funct ions has nct:been studied. On,the

. ^\

J

t;"'Jr,-~' premise that essential.trace eleme nts have importa nt immun o regulato ry

effe~~ ,and the known toxic'ele ments are 'also toxic to the Immune sjstem..del"oostmtion of such interaction'among these two gr? ups of elemen~/~ould^{7"beofbasic andapplie d}signi~.

Cadmium and zinc.,are twoi~portant members of the element groups.They both,belong. to group 118 oftheperiodic ta ble and

, .

^-'

. .

thus have manyphysicala~d ehemical ~mi1arities..They are ~sual1yfound togeth er in nature andalso -tn biological tiSlluCS:'where they com pete for .binding sites,in ligands like meralloeneymes and the heavy, .metal,bingin g protein metallothlonein.Thus they form,an interesti ng_toxiC".and..essential trace

e~7~t

psi;^{in the}

b'iOlogi~1

^.

sysi~m.

^In.the

sUb5~quen; lection~

^of

this chapte r,'salient featu res of ~dmi~m end zincwillbe discuss edv.:i(~,' particular emphasis.on'the immune',system effects.'Metallothionel n, which is involved in themetabolism ofbothcadmium an~ zinc,will be'•.brJefly'.

..,

·:,; ".,',

" '.

"'-:~"'"

, :.'>-

discussed . and.theknowninter aclions betweencadmiu mandzincwillalso bediscus sed.

1.%.CADMIUM • A TOXICREA VY METAL

"

.,Ca d mium is an ubiquitous elem e nt to which ,~ve ryone is'consta ntly espo eed'ata low.jev el. At birth cadmiumisvirtuallyabsentfrom.tissue s, '.butit is gradua,llyacquired from the:"e nvironment,so'.thatinalifet ime an ecerege personl~ving,in.ll:J1i'ndustrlal:,society,acCu mulates"about 15 to 30

~g ~f cadmi~m

^in"his'

,~y ·(~;iberg,

^piscaior,

N~rd~i'

^and

~j:lIstrom.

^.;."..

~

^"

1.974). ~~~?~gh th~e.-acute l(;lldcity of cad~iu~'op, .the lung 'and gastroi,:,te stinal tract hasbeen. known for ~ere.'century.(Whee ler.'1876) , itwasonly in

1950·~ . t~.t· 'th~' d~!18er ~f

^{ch ro nic}

expos~;e t~

^{cadm iumwas}

appreciat ed , !n1942 Nicaud, ~Ii«e"a~d,'^Grcs ~in ^France ~~P?4ed"ilJ) unusual numberofcases of osteo po ro sis associated with'an impairmentof' general .l;lealu\1

:.i.n

an

alkali~~attery

^{facto ry workers}

~~d s~ggested

cad miu m

t~

^{pe"lhCcausa tive}

, age~t ' ,"<Fn1>erg et . ~I..

^{1974): A few}

~e~rs

later( In Sweden, Fnberg'"(1948,'

'i9~0) conductecf'~ '8 ~uJvey o~ worker~­

exposed

to··.cadnii~~~de

^{dust in',}

a~

electri cal'

b81~~ry Pl ant. "~nd

^fOl!Jld.8.

high'.numbCr 'of'cases C!f lung''and kidney

"~a~ag~ ~~ar~ct~rized ' by<.

cm~hysem.~nd

^low

molecul~~ ~t

^'.prote incrie

:rcsPc:~t~e,y. ,~~hiCe,

^then,

mllnysir~:lllar !nvestig~~S)ns performed in"several'cOuntri.es ha*}~nfirtJ:l~

the' danger ,of ,chronic,.long.;term: cadmium "exposure, end

cadm~m

recognized as a seriow occupational•healt h' hazard

..

:~",',

t

The greatestconce rnov~rcadmium pollution'wastrigger~dby reports from' Japan which showed"th~t.chronic cadmium poisonin:g was-not res tricted,to .indlistrial workers'only, but ';8n constitute a'hcalt~hazard to

I

the genera l population as'well..A larg~.pop ulalion grou~'-^{in Japa n"was,} exposed to cad miumbyconta tni!,ationof food and water-thro ugh a mine.

Thetotal dailyintake ofcadmi~m^{was about}~en.foldgreet er- than thatin ._~^.:~' mostpa rts or the world. In'so me areas theexposurewashigh'~nougb^to cause an epide mic

of

severe bonedisea se- the/Iai·itaidiu Qse.(Frib erg et:

.al.,.1974) .·Anotht:rcaseof

'CBd~iU~

^exposure

amon;'th~ 'genCr~I'''p6pulatlon'

occ~rred

^{in'a ,:i1lage}

i~ 'Englan~" TIil::

^{-source of}

cont~ination

^{was food}

grown inan oldzinc-mitlil}8area.The level ctexposur:ewascomparoble"to,

- - 'O' - ...

that of Japan, liver .cadmium.le~lswere highin the expose d' populatl

A ,:,

an dsome evidenceof kidney damage was ~oted, ~utnone devejcped the typical features ofltai·itai difeasl!'(Carrothers anq Smith, 1979; Inskip,

1 1.

'Bera l'and McDowall,19&2). ' ," .'

~\y , ^{~dmium h as n~}

^dsentlal-biologica l

fu~c~n. A1thO~gh.

^bnepreliminary . Com~unicatiQn has'repo rted agtowt~supporting.effe ct of~odmiu m i~ts

(SChwarz, 'and Spallhol z, )976), there are )~o confirmatory repo rts

\

. . , .

subs tantiating this finding. So at,present all evidencc Indicate that

ca~;"ium

is'o!,1$>'a toxjc·element.and its ,presen ce in tells

m'u~t

be regarded as somethi ng tobemir!.lmized.

".-.

environme nt: Industrial processes

.

that use cad~lum include~ctroptatlng,

&.

and general bpth in the indulitrlBI

\ .'

".

,

fabrication of alloys and solders, manu factur e of paints where.cadmium aalts are used as pigments.andplast icswhere it isused as a stabilizer,

and.in manufacture of cadmium-nickel batteries (Bernard andLauwcrys,

1986).Certain'

oth~r

industrial.?processes,

lik~

^produc.tion

~f

^cadmiumand

its com.pounds, smelting and refining ' of~nc and lead ores, recovery of scrap:netal, combustion ofcoalandoil,and disposal ofsewage'and sludge and of waste'plastics produ ces ~dmium ^{as a} byprod uct (Webb, 197.5).

Workersin both types of industriesare at potential dllnger.of inhaling large amounts of cadmium" as ~he'processes involved emit cadmium part icles andincreaseitslevel in theair.

, ' I

Fo.tthe g~ner8.1: POPulati~n, cadmium iFosure occurs mainly thr:ough food..However..cigarcJte"olsmokecon tainsa'significa nt amo untofcadmium, and thus in heavy smokers this is an importa nt additional source of.

,cadmium. Drinking.'WDI~r.an~ ambient air usuapy contain very little

ca~mi\lm, and contri1;lUtl9,l] to total body burden of cadmium from these sources'areinsignificant

Vol~nic activity and.erostcn of land has cont,aminated the earth 's environment,'and

pollut~d ,

its foodsupply with

cacfmiu~

sincethc beginning of Iiic; but it.is,0~1yin the )a,st thr~'^decades'that cadm ium has bien.

"givenaserious'considerationisa'foodcontaminant.As"theindustrialuse

.

^' " "

of cadr.niumincrea sed over the,past thirty years" so did its level

i ?

the

~'~~nvironment~nd.oonseque~tJy^{irrthe food,chain(FOX:} ~979;.^Ryan,Pahren . ~Lucas,.1982). Several studies ,havc been conducted to ~timate the.

,""avenaedally cadmfuminta kefrom food.,The values are extremely variable

depe~ ~~s ,,,

^{on t)le} geographical region, dieta ry habit and source 'Of

r.

contamination. Some foods like oysters.kidneyand liver are known to contain amounts of,cadmium consi~erabiyhigher thnn most other foods.

DietS rich in these foods mayconsi~er8bly_increase the cadmium intake (Mahaffey, Cornellussen, Jelinek and Fiorino. 1975). The reported dally inta~cof cadmium from various countriesshowsvalues of 10 • 51~g/day for the United States. 10•20 p,Flday for the,UnitedKingdom,11 • 18 wI/day.forSweden,15 p.g/day r lJelgium and 20-70 lJ.g/day for Japan (Buchct, Lauwerys, Vandev rde and Pycke 1983; Page, :El·Amarny and Chang, 1986).

F~r

^Cans:a.t' average daily.intake ha; been reported

to

be 67

p.~_ (Kb~atri~k

^and,

Co.ffin,

19?4).'It has been,estimated that cadmium intake of.~39Q p.Yda~ far 50 yearsby'a healthy 70.K~'man would result dn kidney damage (FoX; 1?83).Thusitcan be derived.t~atthe. current d!etary·cadmiumcon~ent ~fnormal people' providesa safety margin of only 4 to 20 fold.

Various studies have documented theImportance of cigarette'smoking as a source of cadmium.An~lysis ~fnecropsy material'from smokers ,show .';;

a higher body burden o.f'cadm:iu~in smokers ascomparedI~ nOt1.smo~ers^. (Lewis,!usko, Coughlin andHerta, 1912j Hahn, Ewers, Jermann,fr~ier, Brockhaus andSchlipkcter, 1987).The amount of tetained cadmiumis also

,

.

^{" , "} ' \ '.~

directly proport,ional10 the numbef of cigarettes',s.h~ked. ByIn vivo measurement,·thelot~1body burden of cadmium was seen tobedoublei~

smoke'f. as,comparedto non-smoke~ (Ellis, Vartsky, Zanzi, CohnBnd Yasamura,-1979). in pregnant women who smoked, cadmium",levels were -,elevatedin theirblood, as also'In theplacenta and fetal:blood (Kuhnert, KUh~~rt".Botto~.and Erhard, 1~82). In a recent survey,bl~cadmium levelwas'seen to.beincreased in smokers with a'dose-effect relatlonihlp

,'>

~

.'

10

to the number of cigarettes smoked per day:Even ex-smokers had higher blood cadmium levels (Moreau" Lellouch, Juguet, Festy,Orssaud and paude,

1983). .

1.2.2.Metabolism orcadmium"

The principal features of cadmium metabolismare its long biological

~alf-lif~ and interaction with other nutrients, particularly zinc. The long half-life"'is due to the.Jack of anyhom~ostatic control mechanis~sthat

can.deal with the increasing intake of cadmium ~th age. The only

protection the mammalian,system offers against cadmium is through the synthesis of the.jntracetlularmetal-bindingprotein metallotbionein."

The main routes ~f ^{cadmium entry into the body the} gastrointestinal tract and the lung. Virtually the total amount of cadmium present in thebodyenters through thesetwoorgans.

Very little quantitative data are.available on th~ absorption of cadmium in~an.Most values arebas~d.on the analysis of human autopsy m~lerials-endestimates of dietary intake.These Ii,ued"human 'dataand supportive animal experiments -indlcateth~tthe gas~roiniestina! absorption of cadmium is very low, l!l1d isgeJler~l1ybetween 3 and 8 percent of the

·intake (Perry,-Thind and Perry,1~6).Cadmium is absorbed by a process of passive diffusion in.the duodenum,;jejunum and il~um (Sahagian,' Herdlng-Berlow and,.Perry1966;~f1agian, Harding-Barlow and Perry 1967).

~~~~._Intestine, ; cad~ium con~~trates in '~

^'epitheliai

,~lls

and much of _~tis subsequently lost when",the cells are shed from.thevilli.However, the observation of enteropathy in'/Iol-ilal dis~ase patients (Murata,") Iirono,

·';~ '.\';

11

Saeki and Nakagawa, 1969)andin experimental animals fed large doses of cadmium'(Richa~n.: Fox and.Fry, 1974) suggest that when cadmium concenua tio." in the.Yllli crosses8 critical level.jhe cells and a substantial amountof cadmium may enter thebody.

damaged

Absorption 9f cadmium.from the lungis,much_~igher,ascompared to the gastroint estinal tract.The rate of absorp tion depends on thr." size and molecular,Iorm of thert5pi~ableparticlesofcad~ium.'J?lc form~scnt l~

cigarette smoke is usually more.completely absorbed than those from industrialsources.'One modo!base'd'onhuman autopsystudy estimatesthat 50percentof'inhaled cadmiumfro mcigarette smok!': is absorbed(Ellnder, Kjellstrom..Friberg, Und ~nd Llnnman, 1976). In non-smokers, inhalation contnbu tesvery.little.cadmiumto thebody.The8~~orbcd fraction.isalso conside?a bly Ie$;'for other resj:>irabresources.Generallyabout2S percent of cadmiuminhaled inambient airisdeposited inthe lower

re~pira~or/

tract.and about,13 to 19 percentof the inhaled cadmium isabsorbed (FnOe'l! etel.,1974).

Nter absorptio n cadmium is transported in blood. The mode. of cadmiumtransport in bloodisunlmowri. but iI is'thought that cadmiumis

~nsported in'pl~ma bound ~o'~ molecular,weightproteip(s) an'd'in erythrocytesboundto haemoglobin and other protein(s)(Nordberg,Piscator and Nordberg," 1971). Animal studiesindicate thatfreshly absorbedcadmium isfirst taken up by the liverand incorporated into metallothioneln.This

cadmjum-melail~;hlonein ~mpIU'

^is then slowly.

relea~d

^fntoblood

~nd

takenupbyother tls.sues, particularly'kidn~(Kellial."1986). In tinue. , cadmium is,~gain boundhito metallolhionein,Which.keep" the metalIn a

"~.'"," ;,' "

12

non-ionic fonn that is eon-tcdc, Kidneys.(or some unknown reason ' produce thehighest'a mount of~mctallothioncin andconce ntrate.the largest amount of cadmium: Uvcr also concentrates a considerable amount of cadm~m. but theamountis.generallymuchlower than kidneys. However.

due'to its larger weight theliver contains a signif'icantfractionof the

to tal'body burden. In kidneys. a cacmfum.gradient occurs with the concentrat ion,in the outer'

Cortex

being'twice that in the medulla .(Uvingst~n.

1 m ).

Cadmi~m_once stored intissues.isr':,leasedvery slowly. Its biological half·Ufe-hasbeen calculefed tobe.5-10yearsin the liver and1~3.3.yeers -fn th'e-

kidri~ ~jcJl5trom.

^1971;

F~~rg

^etaL,

i974)~ V~ry ~ma11 a~ounts

, " A ' . '

or eadmium are norma~_excretedfrom the"bqdy.The principal route~f cxcr~lIon^isthe urine andinnormalman theurinecadmium-'concentration

'varies~m <.Q.5 to2p.glliter.The'I~cl ^ishigher insmokers-than in

non.smo1r:~n. AIsOwith inaessing age., as tissue'cadmium levels.increase,

. '

the urinary output of cadmium also lncreeses, Thus'normally unnary cadmium leveb

\e~t

^the

tot~

^{bodyburden_of the metal}(Kos.tial,·1986),

.

^{\ . . "} ' . ~ -

However,;henre;w da~ge.occun dueto.~ryhi~ kid~ey_~miu~..~d, _~, theexcretion'Increases..d~atieallyand mayreach valuesover100Wp day (Hallenbe ck,1986).

1.2.3.ToxIc efl'ecta or cadmium

"Cadmium

_.

;, tOld.'to,<inuallyevery system'

_.

of the body.

·~.n;~e< I'

.

.

^\,

information exists on the toxiceffects

or

cadmium, however, for obvious :

. .-. .. . . . , .

.

~easons-most

or

tbedata are from'animal studies.Table1.1summa rizes the.

Ii

Toxic Effects of.Cadmium

Type ,Effet ts

Acute Gastroenteritis

Bronchitisand pulmonaryedema

R~productiv~ystem

^effect•

> )

Chronic Renal'damageandproteinuria 11a~7i1aidisease

Chronic obstructivelung disease Essential"hypertension • Carcinoma oflung and prostate• Teratogenesis•

Immunotoxicity •

"~sionally-Mildane~ia, Yellow coloration of teeth, Nasalmua: salulceration, Anosmia,Live'r.damage

• InconclusiVeeVidenceofoccurrenceinman

Nordbergel/:~.I.;'1973 Friberg et 81.;..1974 Parizek;19S6.

&

1983

Pis~tor1 1986 Friberg'et. aI.,'1974"

Stanescuetel.,1977

.xcop er al.,1982

Thunetal.,1985 Machemer et aI.,1981 Koller,1980 • .Borgmanet al.,1986

Bemerd.etaI.,1986

""~

man~estationsof.

aCylC

and chroniccadmium toxicity. In this ~ction the major featuret ofJdmium toxicityare discussed.whileinthe nextsection (1.2.4) the present sta tc.of knowledge on the immune systemeffect.s of cadmiumisreviewed.

. ..:. Acute cadmium'~isoning^israre in.man..Massive-oral

Md

respiratory cadmium exposure hu bee~. reported' foD,owing ingest ion of f~

contaminated bycadnlium.pJatedutensils.(Nord berg, Siorach and Stenstrom 1913) and

rro~ ,

^{inh'BlatJon,:'of}

'~dmium

conta ining 'fumes' in

jndustrl~s '(Be~a'fd an~ LaUwc~~

1986)."

Symp~~~

^of'oral cadmium exposure v.:cre .

~~stly ~'rerer~ble

^to',

th~ .-:~~~~ '~~~Oi~teSl~nal t~act;

^'and

i~~uded_nause"a:

vomiting. diarrhoea,"abdominal"cramps and rarely.shock due todehydration.

Inhaladonof'cadmium

£Umes.

which'-~n~r'^inindustrieswhere cadmium isheated toiivel)'high"tem~rature.multinginthe prod~~on of toxic

·cadmium..oxide fu~es.· 'cit~..b~nchial··.and pUlmo~iuy' irritation and

sometimes fatal

'Putn~nlU)'

^...edema

(S~~

^{Veriter, Frans,-Goncettc,}

R~1s,

^{Lauwerys'andBrasleur.:}'1977). Labora tory.

anima~

^{exposedtolarge}

. .

^{' "}

.

doses of cadmium by oral or inhal~tion route also show similar manifestations,

~~I

^for':some_

Unknown

reasons rodents

tol~rate

^large

.,dOSesof ora!_C8dmi~mWiihoutgastrointestinalrea~tio~(Kostia l,1986).

-e, Fol1~ns·parenterai administration ,of large doses of cadmium to

". ... • -. . ,• i- •

animals,'reproductive system effects are most.prominent. In.'male rats,8.

" . ,

single large dose of"cadmium by.injection characteristically causes

. . I •

heemorthegicnecrosa. of tho testis'(parizek and zahor, 195~.',The necrosis 'iscaused bY'interference'with':'testicul~u ^{blOOdsupply:by}.~d~lum ^(Gunn, GouM"and

~(ie~n,

^1963a).'Testicular necrosiscan also

be ind~d ·~

' , ',

-:

J.

ISv

relatively low doses that do not damage other organs. In female reu, cadmium injection causes hyperemiapi the ovary.~tresia.ott the follicles_

'and features similat; to toxemiao~pregnancy(Par~ek.1983). The cause-of

this predominant involvement of the reproductive organs is not known. In )

h~S,

^no

~effects'"

^on

reproduetive~r8ans

^have

b~n

^{reported,but it is}

hypothesized th~tcadmiu.m.may playa'role in th~ devetopmen.~ of pr~gnancrinducedhypertension (Chisolm.andHandorr,1985).

.

. . . .

^\

1.!nlike acutecad~i~.m toxi~ity.ihlonic,cadmium,toxicity is relatively more com~on. In cadmium e~~ur\all tissue!.·a~uire the metal,but kidne~.c~~Centrate .the high~st ~~otin\and renal damage is the maJor. featu~e.ofcadmium poISoning.Even!'lfte~reSPiratOryexpcsjire,.ki~~ ar~

ultimately.involve~. ^{al.though lung is th first} or~<affected. PrOximal, tubular cells.are typically damaged In chro ic cadmium toxicity resulting'in a Fenconi

~

proteinuria

charact~rized b~\

^{loss of}

Jow.~olecular

^'weight

proteins like .ai-microglobulin, retinol-binding:"protein and

I~zyme;

^and

amino

aci~,

glucose and phosphate [Plscator,

\ 986). In

cadmium exposed

.

\ ~

.workers,increased urinary excretion of high molecular-weight,proteins like albumin,

g~mma.giob'lin.

^{and 'tran!'err;na,e}

Ofte~~delected

as an Isolated findi~g.or inass~iation with low molecular wei

\t

proteinuria,(Bernard,. Bucher, Roels, Masson and Lauwerys, 1979; Buchet, Roels. Bernard and' Lauwerys, 1980). The loss

~f

^{high' molecular}

we~t

^{proteins probably'}

results from an increased glomerular penneabilitY together with,decreased tubular reabsorption (Lauwerys,'B'emard, Roels.vBucbet and Viau;.1984).'.

. ," . , '

---...

"

Renal dysfunctiontyp!~~1I1y OCCltrSwhen the average-cortical concentration reaches 200 to-300 Mfg wei welgJtt,t~e^{'.amount,varia} depending on the

~Of,~mium compound and.rapidity ofadmlnlstrat.i~;~:_(EIIls,Mor~Ti,

. . , . otherwise~ptoma~t; is-'a topic.of,deb~te.However,tubular.dysfunction, o~ce esta~hed,

!s.

irreve~ibleand Usuallyprogressive; thus it isusually accepted ~ an,e'arlysignof cadmium toxicity(Lauwerys and Bernard, 1986).'Recent stUdies in indUstrially exposed workers show that tubular

.

. ^.

^{.' '.}

~~etioneven appeArs at exposure levelsthat ar:, currently a~pted/as

(-

16

ZBnzi,Yu.u"~~,._va_rukyand Cohn, 1981;Reels,Lauwe~and Dardenne, .J983;4'iiCator,1986).The precise mechanism ofcadmium nephrotoxicity is not known. Nonn ally, cadmium-metallothloneln complex released from the liver into the .blood is freely filtered- through the glomeruli 81;1d Jubsequent lytaken up bythe proximaltubular cells.bypinocytosis.Inside thetubular cellscadmiumisboundto newly formedmetallothionein.Ithas t been suggested -that kidney damage isprevented85 long"as tubular cells.

""-prodU~ enOugh" 'mct~lothionei~: '

^beyondthat

th~.

^{'cells atedamagedby000-'}

'mctallothlonein·bound' ·cadmium,ion,and lawmolecularweightproteins that.

\, ,~ -- .' -

..

arc norma'lI~reabsorbed_byp~maltubular'~Ilsbegln.10appe.ar

i n

"urine .(Fnocrg;,'i984). It hal also beenproposedthat the-.iubulai epithelialcell membranes maybedamaged during\theprocess.ofeadmium-meta llothionein

. ,.. ./' . ..

complex .absorption from the tubular ,lumen, and the cadmium- metallothioneincomplexitself maydamagethetubular cells in·additil?nto frecionk:'cil.d~ium{Kostial, ,1986;Suzuki

,

and Cberian,1987).The immune system.~as also been imp.Heated in the pathogenesis_-of cadmium ne Ph rot,ojlcity. In .cadmium treated. animals Immune complex ,glOOl:erulrePhrjtis,(JoSh~ Dwivedi, p~n .·~nd HOlscher,.1981) ap.d ,

C.i~CU.^{It t8} antl.g1~m~ru. ^{lar..bas.ement m.}e.mbraneantibod.Ies_..(Be~ard.

Lauwc Gengoux, Mahteu,-Fcida rt,D~ctand Weeni ng,19841.have beel;l .detee,ed, The health'

impUeatio~

^{of low-molecular} proteinuria, which is

17

normal (verschcor, Herber, Hemmen, Wibowo and Jakubowski, Troj~nowska, Kowalska, Gondek, Sta~ki, Jajte, 1987).

Bone leslolU characterized by osteomalacia, osteoporosis, and spo nta neous fractures are usually late manifestations of severe cadmium poisoning. Itaj-iJai disease was an extreme.manifestation of cadmium- induced osteomali;cia.·'Typ icalI features were bone pain, 'difficulty. .in walking, and s~ntaneoUJ fr~ure. The disease..,typically affect~d-mlddle- aged multiparous women (Fri~rg e(~1.•.1974). Since cO,Deenllation oJ

~dmiumin the bone docsnot increase even'at II.highbodyburden, and cadmium is not known to'haVeanydirect effect on bon~^-the eff~ct^of cadmium..on bone in /tai-iJai disease peuents was probably secondary 10'

~renal tubular,dysfhtipn with increased ufina'ry.loss of calcium BDd phosphate.along With decreased dietary intake of protein ond~Iciumand increased 10M due toprc8Jl.ancl~s.

Cadmium,has also been linked to other diseases. like.essential hypertension and carcinoma of the lung and prostate.'Th e hypothesis of a ,, ~ link between cadmium. and hypertension was based_on theobservati~n"that

.several anti-hypertensive drugs show increased'binding 10 som~ transition

elements .like cadmium. ~pperand zinc. Of these,'cadmium received most attention due to its affinity-for the kidneys,the organ recognized-for_its role'

in

conlTqlling blood pressure (Perry, 1!r72).R~t^studies ~Iearly^Indicate that cadmium at a dose range of 0.1'to 20ppm in dj.!n~ng^{water can} produce elevation'of systolic and,.dias~Oli-c ^blood pre"~~ ^{while dose.}

above this r.a,ogede~eBsel the blood pr~"ure(Perry,': Erloo.er·and Perry,

1977; Peny, Brlahger andl~rry, 1979;Koop~Gtonek,Perry,Erlanger and .Pe~ 1~)".,·~spite of clear evidence,in animal: thereisno'directproof of an assdciation between cadmium and hypertension in .bumans.In ~n

~endemic: areaof high-cedm lum exposure in Japan;examination ofa very large,sample'ofthe''population didnot reveal anyrelationship of blood pressure,with t.hedegree of pollution (Shlgematsu,Mtnowa, Yoshida and Miyamoto,1979).

'

,The

interest In cadmium possible'qrcin~en generated

b y

some earl)' epidemlologicill Studies'shoWing' an increased im:ide'nce-of

~ ,

" . '"

pro~tatic:and.lung,cancer _in occupationally ~d workers,C)Gpl~ng.

waterhouse,1967;Le~en,lCe, Wagoner ,snd; Blejer•.1976).But in'm,ostoC' these studiesthe number ofo~;n..ed caseswere toosmalltopermit 8 finn con~lu~I.On,.and oft~n the,_possible ef!eets of cocarclnogens.like tobaccoand other Industrialchemical~werenot considered. However,'in ratsand mice, cadmiumsiv7nbyinjectionor at a large0~1^{dose for a} tong pedod vproduceslnte~titial cell.tumour in the testesor sarcoma at the site of injection(Haddow,Roe, D~kesand -Mitchley,'1964;.Bernhard, Vogel and'Loser,'1987). Also prolonged inhalation ofcadmium'Chloride/\, /'fumes at~tire'17veiS within 'the current'occupational limits has been / ' demonstrated to cause a - dose~~_pcndent.increase inlung cancer in'rats ..\ (Takeneke,-OI~ligeS, ^Konig,Hochr~iner^and OberdC:~ter.:1983). ^{In contrast .}

'to dennr-weanim.al

studic~

_. ^results

fro~

_. human sJudles_

,

^...

~re Inco~c1usive. A '

recent report"of a s~udy in which a large cohortof,industrially exeosed workers~.e~,~ined, a d~finlte:'incre~c in'lungcan~r wa~o~served (Thun, Schnorr,Sm.i~l,\H81peritiand Lemen, 1985).HOWever, in another almilar study,nc'association

'betwe:~n ' ~dmi~m

^{and . found}

19

(Sorahan,1~87).Thus the~iationof cadmiumBnd.humanmallgn~ncles is notyet~establishet'"'"but theevidencestronglysuggests that c"admlumis a carcinogen.

Other toxic effe.cts oftenaunbuted to cadmium,incJude teratogenicity and embryotoxicity (Machemer and Lorke,.1981;.Machemer and

Lorke, - -

1981). Cadmium has also been reported to'cause mild,anemia, yellow

• I . - •

colorationofteeth,anosmia,ulceration ofnasal' mucosa and signso~ liver damage (BernardandLauwerys,1986).

1.1.4. Effect or cadmium.~nImmune responses

Th~effects ofcadmiumcompoundsonthe Immune system bave been studied eXtensiVely in dj~erent animal species in recent years and the topic has been",reviewed (Koller, 1980; Exonand Koller.1986).rCadmium has been shown to significantly affect the immune responses, however a review of the literature- reveals mpny inconsistencies. The antibody response and cell-mediatedimmunity have been.shown to be bothenhanced and suppressed following cadmiumtreatment,The ~ffect varies dependi,ng 'on the dose,·,duration and route of cadmium treatment, temporal relationshipbetween cadmiumtreatment and administration ofantigen and

,the species of animaltested;·Thisisnotunexpectedas cadmiumabsorption

fromdifferentsites is known' tov~rY·'andthe effect of'a'toxic elementon an intricatelycontrolledsystemlike theimmune s)'item wouldbeexpected to bedose dependent.

Althoughthe results'

of

different studiesere ambiguous,cadmium generallyimmunostippressive(Koller,1980),Primaryond secondary Immune

. \

<, '. responses against heterologous antigens'a~e suppressedin rats and mice treated 'with large oral doses-of300 ppm cadmium,in drlnldn.8water for 10 weeks.(Kotler, Exoo and Roan. 1975) or by_cadmium i\njection [Bozelka,"

Burkholder and Chang, '1978; Shippee. Burgess,.Ctaverra, DiCapua'and

. "" .

'.

Stake, 1983) or inhalation (Graham, Miller, Daniels, Payne and Gardner, 1978; Knystyniak, Fournier, Trottier, Nadeauand"Chevalier, 1987). In contrast,low.oral

d~s

^{of'25or'Soppm}

ca~mium i~ 'drin~g

'water has' been reported to have no effect,.on.'primary antibody forming,cells (Muller,. Oi1lert. Krause, Jautzke; Gross arid Diaman\slejn~-

i979;

Wesc~nberg and

.Wesenberg, )983),'or to" increase (Malave and DeRuffino, 1984) or to

de~.r~ase (Blakley, 1985;regman,Au and ~andra,1986)'the~r'numbe~:

Also parenteral administration of 0.15.mg of cadmium in mice before antigen challenge increases IgM andfgGantib~y.production (Koller, Exon and Roan, 1976)."but at doses of"1.8 mg/kg body w~ig~t suppresses antibody responsed~e to direct inacnvation of B~lIs (t::ujimalO, 1985).' Cadmium-Jnjection initiated 7 days.before antigen.administ~tionsuppresses anti~ synthe'sis., b~t it enhances the'responsewhen initiated 14-days., earlier(Jones,Williams andJones,1971).

·Other data

su~est

^that

~llular

^'immu,ne

functi~'ms .

^are

~also

affected' by cadmium; Delayed cutaneous hypersensitivity!caction which is a classical in vivot~t for cell-mediated immunitY'is impaired

bY

cadmium inmice\ .(Muller et at., 1979).However, theiii;vurotests.of cell-mediated immunity

. .. . "

. .

^{" \...}

-

.dc not show, ~nif~~.effects f~l1owi~g cadmirm exposurec Lymphocyte tra~f~rmation in'viJro.tomit~gens,.like p~~tohaem!lgglutinin (l?HA);

concan~valin ^{A.(Con A)-}a_~~ po~eweed'^mjl,eri.(P~) ^isBeOm~o~ly^.

t:-~

emp10rcd \fS8Y,of' cell-mediated}mmunity: The plantlectlns PHA and,Con'

l : ~ ..\

',; '. 1 i!i':';':" .':'''.'';';:'i L,''> • . ; 'c':>.' ;:;';:;..'.'.. ':;C' : . :, kv , .,""".,..:, .:

i •.;,:".:...

~ :'

r:

\

,21

A acnvate T cells;and PWM.activates both T andB

c~ls.

^{In somestudies,}

lymphOcytes frommice andratsexposed tocadmium have been shown to haveincreased

re~po'lise<lto ~

cellmrtogens(Muller-'C1t·al.,1979;

'M~lave. ;nd.·

DeRuffino1984).whereasin ethersno change (WesenbergariC!.Wesenberg,

. 1~~ ,'

^{; Blakley,}

1~8S,)

^ora,

d~re~se

^{(GaJJSkiand S,harms,1978) In.respo.nse.}

has been.observed.,B cell responses re general,lyincreasedIn .cadmium treated animals (Muller:et.al.,:1979; Koller,'Roan and'Kerlcvlie't, 1979;

Blakley, l?8s),These

contlicti~,,8'

^{repo inalcate that}

~dmluin

^can'impair

" '

some parametersofthe immuneresponse whileaugmentjngothers, ' ,

Oth~; i~~UO"

^.cell,

~~~' ^{the ,} J~~~,ge,

^and polymorphonuclear ..

leukocytes are

~~ ~dve'~elY a~~cted f~

^{cadmium. Phagocyticcapacityo£,}

these cells is reduced (Leese,

~i1kwO~h

^and Warringto'n, 1978).·

.:~acrOphageS

^from

cadmi~m

^{··trested!animals}

pro~uce

^{less macrophage}

~

, migration inhibitor"faeeor, 8 Iymphokne (Kiremidjian&humacher, Stotzky, "

,. Likhite,Schwartz

~nd Dic~tein: 1~,ljll , ~re sl~ggisti

in movement

a~d

^less

responsive to macrophage migraton. inhibitor factor (Kiremidjian.

Schumacher,

"~totzky, '

^Dickstein

,.an~

^Schwartz, '1981):"

'AlSO~

^cadmium

treatment.inhfbin"the'ability o~ i~I-"".:acrophages to destroy

"?"

~11s in vitro(Nelson, Kiremidjian humacher and Stotzky; 1982), In

• addition,.large doses

~f cadrniu.~

^r

a~icts, lh~ ma,tu~tion

^o£lymph,oid cells and resultsinan increase inlargei~maturecelltypes (Ohsawa and KawaJ~

. \1981;,~ B~;c~iel., ~~dle~;.

^{Cameron,pi,ner,Urn,}

E ,Il~S. 'an~

stewart"

198;)"

A>

a result of..g~ner~lized immun~upp ssion, ca~~jum,treated ~~lmal.show increased susceptibilityjobacterial, viral and protozoal infection (Cook, 'H.offmann :md

D;~O'

^19(5.;Gaine

r~ 1~7; ~~n.

^{Patton.8.ndKoller,1979;}

,Bxcn,.~lIerand Kerkvliet,1979~,Jr~~~en~ ~£,~ncer ~.also IncrcaedIn

\, .,