Prealbumina, precalicreína e protrombina na forma hepatesplênica da esquistossomose: catabolismo aumentado de proteínas da coagulação?.

Rev. Inst. Med. n'op. Sã.o Paulo 26(5) :237 -240, setembro. outubro, 1984

PREALBUMIN, PREKALLIKREIN ANÐ PROTHROMBIN IN HEPATOSPTEN¡C

scHlsrosoMlASlsr INGREASED TURNOVER

oF

THE

cLorilNG

pRorElNs? (*)

Nora MANOUKIAN anil Durual R. BORGES

SUMMARY

Prealbumin, prekallikrein and prothrombin were evaluated

in

20 patients

with the hepatosplenic form

of

schistosorrriasis and

in

18 subjects

of a

control

group. lüith

the prealbumin concentration values obtained

in

the latter group

a reference interva! (0.5

_-

99.5t/o)

of

g7

to

389 mgll, ,was calculated and plasma

levels below 97 mg/L assessed

in

2

patienis

a

deficiency

in

hepatic synthetic

capacity. Mean (

i

SEM) prealbumin _{concentration}

in

_{the 18 remaining patients} (232

-r

13 mS/L)

did

not differ

(p >

0.05)

from

that

of

the controt group l.243

L

11

mg/L).

Otherwise tt:ese 18 patients had both mean plasma prekallikrein (34

Í

1.3 pKat/L) and prothrombin-antigen (81

j

3 mg/L) concentrations lower

(p

_<

0.01) than those of the control group (40 +-

_t.4

_{rÃ<a,t/L and 100}

_È

_{3 mg/L,}

respectively). The present findings do

not

necessarily rule

out

the possibility that prekallikrein and prothromb'in may asses a minjmal hepato-cellular damage

earlier than prealbumin;

but,

since

the latter

protein have

a

shorter half-life

than the formers and

is

a reliable index

of

hepatic synthetic capacity, the pre-sent report supports the

_{ffiothesis of}

an increased turnover of clottirìg proteins

in

some patients with the hepatosplenic form

of

schistosomiasis.

UDC 616.995.122

Schistosomiasis is prevalent in large world

areas affecting 200 million persons;

in

Brazil, S. mansoni affects about 10 m,illion persons (ca

ß%

of. the Brazilian population). Abnormal

la-boratory clotting tests are frequently observed among patients _with the hepatosplenic form of

the parasitosis althcugh hepatocellular function remains good

14.

The importance

of

unders-tanding these clotting alterations is clear when

we consider that the main cause

of

death is

bleeding (hematemesis _{and/or melena which}

follows

gastro esoph4geal varices rupture); ciottlng laboratory abnormalities may even pre-clude,

in

these patients, necessaqy propedeutic and,/or surgical procedures.

TNTRODUCTION

(*) Wo¡k carried out at the Dept. Medicine, Division castroenterology, Escola Paulista de Medicina, SP and

sup-ported in part by fellowship from CAPES ând g¡ant from Conselho Nâcionat de Desenvolvimento CientÍfico _- CNPq, Brazil. Address for reprints: D. R'. Borges, C.P. 20239, 01000 _- São paulo, Sp, Brazi1

237

In

schistosomiasis the clotting defects have been assigned either

to

impaired rates of

pro-tein s¡mthesis

by

the liver and/or

to

localized

consumption coagulopatþy. Improvement, in

some patients,

_of

_{clotting tests} after heparin

administration or splenectomy supports the hy-pothesis

_that

consumption

of

clotting factors may occur in an anatomically and hemodynami.

cally altered spleno-portal venous systems 7.

Chronic

consumption coagulopathy has

been described

in

other diseases accompanied

b'y splenonregaly 6 as

well

as

in

liver

cirrho.

sis

16. But

the

role

o{

these

two

variables (synthesis and turnover of clotting proteins) in

schistosomiasis patients has not yet loeen

MANOIIKIAN, N. & BORGES, Ð. R. _- Prealbumin, prekâllikrein and prothrombin in hepatosplenic schistosomiasis:

increa-sed turnover of the clotting proteins? Rev. Inst. Med. trop. São Paulo 261237-240, 1984.

In

this

paper we have compared plasma

levels

of

two

clotting proteins (prekallikrein .and prothrombin) 'with those

of

prealbumin looth in sclristosomiasis patients and in subjects

of

a

control group; prothrombin

time

(PI), activated partial thromboplastin

time

(APTT)

and albumin were also assayed. Prealbumin was selected because

it

is a true index of liver

function e.

M.{TERIAL AND METIIOÐS

Thirty eight adults were studied: 20

ambu-latory patients with the compensated form of hepatosplenic schistosomiasis

and

18 healthy subjects from the same social-economical class as the diseased ones. The diagnosis of the

pa-rasitosis was confirmed

by

the finding

of

S. mansoni ova in feces andlor rectal mucosa; all patients had enlarged spleen

(at

least

5

cm

from the

left

costal

border).

From each

indi-vidual venous citrated blood was collected by

a

double-syringe technique:

after

2

to

4

ml of blood have been drawn with the first syrin-ge,

it

was removed leaving the needle in place;

the second plastic syringe was then attaohed to the needle and the speoimen collected. The

contents

of

the latter

syringe 'was presumed

to be free of tissue factors that may contami-nate specimens during venipuncture 11. After a

room-temperature centrifugation plasma was assayed

for

IÍ1, APTT, prekallikrein and

albu-min; plasma aliquots were stored

at

-20"C for

ulterior assay of prealbumin and

prothrombin-anti,gen. Prothrombin time was measured by a one-stage technique using human brain throm-boplastin prepared as described by POLLER &

THOMSON 13; _{APTT was performed using}

Ac-tivated Thrombofax

from

Ortho Diagnostics;

Iesults

of

these

two

clottÍng assays "\üere ex-pressed as a ratio (subject _{time: normal time).}

Albumin was determined by densitometry after cellulose acetate gel electrophoresis.

Prealbu-min

and prothromloin-antigen were measured by radial immunodiffusion tz _using plates

M-Par-tigen

from

Behring Institute (W. Germany).

Plasma prekallikrein was activated

by

a

100

mgll, solution

of

dextran-sulphate (Mr 500 000, Pharmacia, Sweden)

in

70Vo acetone and the

kallikrein amidolytic activity was measured 1

on the chromogenic substrate 52302 (H-D-Pro-Phe-ArgpNA)

from

Kabi Diagnostica, Sweden.

238

Mean values were compared

by

Students

"t"

test.

RESUT,TS

\üith

the

prealbumin values obtained in

the control group (Table

I)

a

reference

inter-val (0.5

-

99.5Vo)

of

97

to

389 mgll,'was cal.

culated. In two schistosomiasis patients (No. ?

and

15, Table

II)

prealbumin plasma levels

lotwer than 97 mg/L were interpreted as the

result of impaired rate of protein gynthesis by

a

diseased

liver;

these

two

patients had also the lowest levels of prekallikrein and

prothrorn-bin

antigen (Table

II)

and

were excluded when means showed in Table

I

were calculated.

'fhe remaining 18 schistoso niasis patients had

similiar

(p

those of the control group (Table

I);

in

these 18 patients the mean (

i

SEM) albumin _level (44

i

0.6 g/L), PT ratio (1.14

-f

0.03) ând APTT

ratio

(1.08

-f

0.03)

did not

differ (p

>

0.05)

from those of the control group (46

L I

g,/L,

1.08

t

0.02

and

1.03

I

0.02 respectively). Other¡wise both mean prekallikrein and mean prothrombin-a.ntigen levels were

lower

(p (

0.01)

in

the schistosomiasis group ,when

com-pared

with

the

control one (Tab

_e

I).

One schistosomiasis patient (No. 17, Table

II)

with

a

plasma prealbumin concentration

on$

mar-g,inaly "normal", i.e., inside the reference

inter-val adopted, must be considered

a

borderline case.

T¡,BLE I

Mem (+ SEM) values of prealbumin, prekallí-krein and

prothrombin-antigen in the 2 studied groups Group Prealbumin Prekallikrein Prothrombin-antigen

mC/L ßKat/L mg/L

Controi

(818) 243 ! lL

Schistoso-miasis 232 + LB

(n:18)

"t" 0.61

p >O.05

DISCUSSION

The schistosomiasis coagulopathy may be

attributed

to

at least two variables: decreased synthesis rate and íncreased turnover

of

clott-ing proteins.

In

order

to

distinguish between

40 + L.4

34 + 1.3

2.92 <0.01

100È3

81 È3

o.+Ð

MANoUKIAN, _{sed turnover} N' & BoRGES, D' R,. _- Prealbumin, prekallikrein and. prothrombin in hepatosplenic schistosomiasis: incroa. of the crotting proteins? Rev. rnsú. Med. trop. são paulo z6tzg7-24o, L}B .

TABLE II

Prealbumin. prekallilrein and prothrombin-antigen in the schistosomiasis group

Patient No. Prealbumin P¡ekallikrein p¡othrombin-anttgen m'e/L pÏ<at/L mg/L

I t

5

6 7

I

10

11 L2 13 74 15 16

77

18 19

20

198

198

275 zoc 226

87

285 236 236 245

339

295 226

94

172

IIb

265

772

181

28 34 47

32 36 14

36 36 28 44 37 36

18

39 32

4L

¿c 23

noreactive protein _but not its coagulant activi_

ty

we could

not

evaluate a possible impaired

car oxylation as had been previously fo;r.rnd. in other liver diseases 2.

A. normal prealbumin plasma level

of

the schistosomiasis group ,was

_in

_{variance with}

decreased prekallikrein and prothrombin

con-centrations. Measurement

_of

circulating 1evels

of prothrombin antigen

is

an excellent indica_

tion

of

hepatic s¡mthetic capacity

s;

although we cannot rule out the _{possibility that this} clot_

ting protein may asses a minimal hepato_cellu_

lar

damage earlier than prealbumin. there are

no reason

to

suppose that prealburnin synthe_

sis may be selectively preserved

in

schistoso-miasis

patients.

As

a

matter

of

fact the 2,8 days of prothrombin _{loiologic half-life ls ,is} lon-ger than the 1,9 days of prealbumin haü-life s. Prekallikrein half-life is supposed to be around 36 h in rats 3 _{but there are no human data} avai-lable. These facts may altogether indicate that

in

schistosomiasis patients _with vrell preserved

hepatic synthetic capacity a decreased.

concen-tration of a clotting protein is secondary to an increased

turnover.

Such

a

situation had al-ready been descriloed

in

cirrhosis 4 _{where liver}

functions are not as well preserved as in

schis-tosomiasis. We can conclude

by

stating that,

facing the "dilemma" decreased synthesis

ver-sus increased turnover

of

clotting proteins in

schistosomiasis:

a)

global clotting tests may not be useful; and

b)

prealbumin as well as individual clotting proteins must be evaluated.

The

correct interpretation

of

laboratory

clotting tests in patients with the hepatosplenic

form of

schistosomiasis

is

fundamental when

propedeutic anðJor surgical decisions must be made.

Unfortunately the evaluation of isolated

cli-nical cases

will

seldon

be

simple, mainly in

borderline cases (as exemplified by patient 1?, Table

II)

and in patients with moderate to se-vere degree of undernutrition, a situation

com-monþ found

in

countries where schistosomia.

sis is prevalent.

RESUMO

Prealbumina, precalicreína

e

protrombina na

torma hepatesplênica da esquistossomose:

ca-239

60 ?0 84 94 74 84

51

89 '14 89 79 o7 92 83

94 58 83 88 66

the effects of these two variables on

a

group

of patients _{with the hepatosplenic form of the} parasitose, _{albumin, prealbumin, prekallikrein}

and prothrombin were assessed. prekallikrein

acts

at

the very

initial

(contact) phase when

the

intrinsic clotting pathway

_is

activated 8

while prothrombin _acts

_at

_{the final}

_{step of} the coagulation cascad.e; prealbumin, obviously

not part

of

the clotting system,

is a

sensitive

index

of

hepatic gynthetic capacitye.

In

two

patients (No. ? and 15, Table

II)

an impaired synthesis _{was then admitted.. Although a nor_}

mal prealbumin plasma level indicates a nor_

mal rate

of

protein synthesis

by

the

liver

a

decreased plasma level _{may reflect either} im_

paired synthesis

or a

poor nutritional condi-tion 10. _{Ar¡yway data from these 2 patients were} not included ,in the means showed in Table I.

The remaining 18 patients had ,'normal"

preal-bumin and alpreal-bumin plasma concentrations, i.e,

they do not differ from the control group; pT

and APTT mean values were also "normal" in

these 18 patients.

It

must be emphazised that global clotting tests are not sensitive to minor

deficiencies

o

clotting factors; indeed

prekalli-krein and prothromloin mean values were only

L5% and I90/o respectiveþ lower

than

those

found

in

the control group, although these d.if-ferences are statistically sj,gnificant

(p

_<

0.01).

immu-M.q,NOI'KIAN, N. & BORGES, D. R. _- Prealbumin, prekallikrein and prothrombin in hepatosplenic schistosomiasis: increa-sed tuÌnover of the clotting proteins? Rev. fnsú. Med, úrop. São Paulo 26t237-240, 7984,

tabolismo aurnentado de proteínas da coagulação?

No

plasma

de

20 doentes portadores da

forma hepatesplênica da esquistossomose man-sônica, assim como

no

de 18 indivíduos

nor-mais,

foram

avaliados pré-alburnina,

precali-creína (atividade amidolítica)

e

protrombina-antígeno. Os valores da concentraçáo

plasmá-tica de pré-albumina obtidos no grupo controle

permibiram que se estabelecesse

um

intervalo

de referência (0,5

_-

99,50/o) de 9?

_-

389 mgll. Valores anormalmente diminuidos de

pré-albu-mina encontrados em 2 dos doentes indicaram nestes uma disfunção hepatocÍtica de síntese protêica.

Nos 18 doentes restantes a média da

pré-albumina (¿32

t

₁₃

_mgll)

não diferiu

(p

>

0,05) da do grupo controle {243

!

11 mgll)

en-quanto as médias da atividade de

pré-calicrei-na

(34

t I

pKat/l) e protrombina (81

i

3'0

mg/l)

estavam significativamente diminuídos

no grupo de esquistossomóticos 1p

q

0,01). Estes dados não excluem a possibilidade da

pré-calicreina

ou

da protrombinâ-antígeno

se-rem marcadores de síntese protêica pelo

hepa-tócito mais sensÍveis que

a

pré-albumina; se

entretanto

a

concentraçáo plasmática normal

desta proteína indicar preservaçáo desta fun-ção, a diminuiçáo de fatores de coagulação

po-derá ser secundária

a

um

"turnover"

aumen-tado dos fatores de coagulaçáo na forma hepa' tesplênica da esquistossomose.

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74

t5