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Plasma levels of endothelin-1 and thrombomodulin in burn patients
Copyright
0 1996 Elsevier
Burns Vol. 22,. No. 8, pp. 594-597, 1996 Science Ltd for ISBI. Ali rights reserved Printed in Great Britain '1305-4179/96
ELSEVIER
PII: SO30541
79(96)00063-O
levels of endothelin-I in burn patients H. Nakae’,
Plasma concentrations of endothelin-1 (ET-l) and tkrombomodulin (TM) were determined in patients with burns to examine their relation to tke severity of illness. Tumor necrosis factor-a (TN&) was also measured, and its relationship to ET-l and TM determined. Twenty-three burn patients were evaluated, who had a total burn surfacearea (TBSA) of at least 20 per cent. ET-l was measured by radioimmunoassay (RIA). TM and TN.&z were measured by enzyme-linked immunosorbenf assay (ELISA). Both the ET-1 and TM concentrations were significantly higher in the patients wko developed sepsis than in those who did not and in the patients who eventually died than in those who survived. Maximum plasma concentrations of ET-l and TM were signiJicantly correlated with the acute physiological and chronic health evaluation 11 score. There was also a significant correlation between the plasma levels of TNF-a and both ET-1 and TM. ET-l and TM closely reflect the severity of illness in patients with burns in the infectious stage; TNT-a may be involved in the production of ET-:! and TM. Copyright 0 1996 Elsevier Science Ltd for ISBI.
Burns, Vol. 22, No. 8,594~.597,1996
Introductian Endothelin-1 (ET-l), a vasoconstrictive peptide, was first found as a secretion product of cultured swine vascular endothelial cells, has a variety of biological activities in addition to vasoconstriction1-4. Thrombomodulin (TM), a protein found in the membrane of the vascular endothelial cell, is a thrombin receptor and, when activated, exerts an antithrombotic effecP Endotoxins and cytokines stimulate the vascular endothelial cells to produce ET-1 and TM9-I’. Blood concentrations of ET-1 and TM are also increased in patients with disseminated intravascular coagulation (DIC)12-1j. A correlation between endotoxin, tumor necrosis factor-a (TNF-c() and the pathological condition of patients with burns has been previously described16-18. In this study, the relationship of ET-1 and TM to burn severity and TNF-a was examined.
Informed obtained
and thrombomodulin
S. Endo’, K. Inada”, Y. Yamadal, ‘T. Takakuwa’
‘Critical Care and Emergencv Center and ZDenartment I Ywate Life Science Insti&te,‘Morioka, Japan
Materials
$15.00+0.00
and methods consent for participation in this study was from the patients or their families, The
of Bacteriology,
and M. Yoshida” Iwate Medical
University
and
study was approved by the Ethics Committee of Iwate Medical University. Twenty-three patients, who had burns over dt least 20 per cent of their body surface and who survived more than 1 week after sustaining the burns, were studied. There were 10 men and 13 women, age range 19-76 years (mean 52.0 k7.6 years). The total burn surface area (TBSA) ranged from 22 to 98 per cent (50.2 +20.4 per cent). Of the 23 patients, 13 survived and 10 eventually died. Fifteen patients developed sepsis during the course of their illness. Serial blood sampling was begun immediately after burns were sustained and was continued until the syrnptoms improved or the patient died. For the ET-1 and TM assays, blood was collected in a trasilol-containing ethylendiaminetetraacetic acid (EDTA) tube and immediately centrifuged at 3000 rprn for 15 min at 4°C to obtain plasma. The plasma was stored at -80°C until assayed. Plasma levels of ET-1 were measured by radioimmunoassay (RIA)19. The normal range was 1.45-3.03 pg/ml. TM levels were determined by enzyme-linked immunosorbent assay (ELISA) (Fuji Pharmaceutical Corp., Tokyo, Japan)2O. A level of 4.5 q/ml or less was regarded as normal. TNF-a levels were also determined by ELISA (Medogenix, Fleurus, Belgium). The limit of detection was 3 pg/ml. The acute physiology and chronic health evaluation II score (APACHE II score)21 was used as an index of the severity of the illness. Data were expressed as mean ) standard deviation. Differences were analysed with. the unpaired Wilcoxon test. Pearson’s formula was used to evaluate correlations. P values CO.05 were considered to be statistically significant.
Results The TBSA values in the surviving group (33.2 _+12.3%) were significantly lower than those in the non-surviving groups (65.9 -t 18.2%) (P = 0.0002). The TBSA value in patients with sepsis (59.1+ 18.8%) was significantly higher than the corresponding value (33.5 _+10.4%) in patients without sepsis (P = 0.0006). In the early stages after the burns were sustained, little increase was seen in the levels of ET-l or TM.
Nakae et al.: Plasma levels of endothelin-1
p-O.0422
I e
0
595
and thrombomodulin
15
.
. :. T
.
10 0.
-+
8 -
!
. .
i 8
n=23 r=0.8341 p<0.0001
5
sepsis (3
sepsis (+I (n=15)
(n::%)
iurvivors (n=l3)
Ncnsurvivors
Figure 3. Correlation and the accompanying
(n=lO)
Figure 1. The serum level of ET-1 in patients with and without sepsis and in surviving and non-surviving patients. Horizontal bars indicate mean values. Increases in ET-l (data not shown).
and TM were The average
triggered maximum
by infection
ET-1 level was 7.4k3.0 pg/ml in all patients. In patients with sepsis, the maximum ET-1 level was 8.4 + 3.0 pgknl, a value significantly higher than the 5.6 k2.0 pg/ml in those without sepsis (Figure 1). The maximum ET-1 level in the non-surviving group was 8.6k3.0 pg/ml, significantly higher than the 6.6 f2.8 pg/ml in the surviving group (Figure 1). The average maximum TM level was 6.6 +2.9 q/ml in all patients. The maximum TM levels in patients with and without sepsiswere 7.7) 2.7 rig/ml and 4.5 _+1.3 rig/ml, respectively (P = 0.0159) (Figure 2). The corresponding level in the surviving group was 5.6f2.3 @ml and in the non-surviving group, 7.9f2.9 @ml (P=O.O493) (Figure 2). The maximum ET-l level was significantly correlated with the maxi.mum TM level (r=0.8341; P
p=o.o493
p=o.o159
endothelin-
0
20
10
0
1 (pg/mL)
between the maximum TM levels.
ET-1 levels
with the TBSA value (r =0.6980; P=O.O002), and the maximum TM level with the TBSA value (u= 0.7752; P < 0.0001). There was a significant correlation between the maximum ET-l level and the “accompanying TNF-a level (Figure 4). A significant correlation was also found between the maximum TM level and the accompanying TNF-a level (Figt~re 5). The maximum TNF-c( level and the TBSA value were significantly correlated with each other (Y= 0.4268; P = 0.0423). The maximum APACHE II score averaged 25.4-L-7.5 in all patients. The ma,ximum APACHE II score was 22.2f6.6 in the surviving group and 29.5 &-6.8 in the non-surviving group, with the latter being significantly higher than the former (P=O.O178). In addition, the average maximum APACHE II score was 27.817.2 in patients with sepsis, significantly higher than the 20.9 i 6.0 in those without sepsis(P = 0.0337). There was a significant correlation between the maximum APACHE II score and the maximum ET-l level (r=0.6974; P= 0.0002) (Figure 6). The maximum APACHE II score was also significantly correlated with the maximum TM level (Y = 0.6779; P =0.0004) (Figure 7) and with the TBSA value (Y= 0.6799; P = 0.0004).
15
.
. ! -
t
0 . .
10
5
. p=O.O062
sepsis (-1 sepsis I+) (n=8) (n=l5)
Survivors (n=l3)
CXkSUViVOl
lb2
(n=lO)
Figure 2. The serum level of TM in the septic, non-septic, surviving and non-surviving patients. Horizontal bars indicate mean values.
lb3
TNF- a (wjnb) Figure 4. Correlation and the accompanying
between the maximum TNF-c( levels.
ET-l
levels
Burns: Vol. 22, No. 8,1996
596
50]
,
a
10 2
lb2
lb3
TNF-a Figure
.
n=23 r=0.5356 p=O.O084
l
r=0.6779
thrombomodulin
(pg/mL)
5. Correlation between the TM
5
10
1 13
(ng/mL)
7. Correlation between the TM levels and the accompanying APACHE II score. Figure
levels and the
accompanying T’NF-a levels.
Discussion Inflammation in the burn patient is assumed to be most severe immediately after the injury. The inflammatory reaction is thought to be at a maximum when. TBSA is most pronounced. It was previously reported that endotoxin and TNF-x are not markedly elevated in the plasma of patients in the early stage of burns and that their concentrations are not correlated with TBSA’“,“. The present results revealed that ET-1 and TM were not markedly elevated, and that neither of them was correlated with TBSA. That is, plasma levels of ET-1 and TM appeared to be independent of the severity of inflammation in the early stages of injury. However, ET-1 and TM were significantly correlated with TRSA throughout the course of the disease, and their levels were significantly higher in the group with associated sepsis than in the group without sepsis. Plasma levels of ET-1 and TM were also significantly higher in the non-surviving group than in the surviving group, and ET-l and TM levels were significantly correlated with the APACHE II score. The chance of infection is thought to be at a maximum when burn size is most pronounced, and morbidity is most severe. ET-1 and TM could not
r =0.6974 p=o.o002 n=23
simply be sophisticated measurements of burn size, because they were not correlated with TBSA in the non-infection period. Thus, ET-I and TM levels appeared to closely parallel the degree of inflammation in the infection period and severity of morbidity related to burns. ET-1 is a vasoconstrictor peptide with other bioactivities and is believed to be involved in the onset of DIC when produced in excess by vascular endothelial cells’4,‘j. TM is a membrane protein that exerts an antithrombus activity on endothelial cells; elevated plasma levels of TM reflect the degree of endothelial cytotoxicity. Some reports have shown that endotoxins or cytokines, which are important in sepsis and septic shock, stimulate the vascular enidothelial cells to produce ET-1 and TM”“. In particular, the production of TM b:y endothelial cells is increased about 40 per cent by TNFP, most likely due to the release of TM from the cell membranes as a result of endothelial cytotoxicity of TNF-a. In this study, the level of TNF-m produced by infectious stimulation was significantly correlated with ET-1 and TM levels, suggesting that TNF-c( stimulates ET-1 and TM production by vascular endothelial cells. ET-1 and TM levels were significantly correlated, probably because levels of both factors closely parallel the severity of vascular cytotoxicity due to stimulation by TNF-a. In patients wh.o developed sepsis and multiple organ failure, levels of both ET-1 and TM also tended to be high, these high levels tended to be Iprolonged. These findings are consistent with reports by Asakura et al.12,15, The present findings suggest that ET-1 and TM are intimately involved in the developrnent of morbidity in the infection stage of burn patients, and that their concentrations closely parallel the severity of the pathology.
Acknowledgements 10-1, 0
10
endothelin-
20
1 (pg/mL)
Figure 6. Correlation between the maximum ET-1 levels and the accompanying APACHE JT score.
This research was supported, in part, by grants 01870116, 03670220 and 05770882 from the Ministry of Education, Science and Culture of Japan, from the Marumo Emergency Medicine Research Fund, and from the special research grants for the development
Nakae et al.: Plasma levels of endothelin-1
of characteristic education by School Prornotion Foundation.
and thrombomodulin
the Japan Private -
597 12 Asakura H, Jokaji H, Saito M et al. Plasma levels of soluble thrombomodulin increase in cases of disseminated intravascular coagulation with organ failure. Am J Hevzatol 1991; 38: 281.
References 1 Yanagisawa M, Kurihara H, Kimura S et al. A novel potent vasoconstrictor peptide produced by vascular endothelial cells. Nature 1988; 332: 411. 2 Miyauchi T, Yanagisawa M, Tomizawa T et al. Increased plasma concentrations of endothelin-1 and big endothelin-1 in acute myocardial infarction. Lutz& 1989; ii: 53. 3 Saito Y, Nakao K, Mukoyama M, Imura H. Increased plasma endothelin level in patients with essential hypertension. &’ Exgl J Med 1990; 322: 205. 4 Shichiri M, Hirata Y, Ando K et al. Plasma endothelin levels in hypertension and chronic renal failure. Hypevtensioll 1990; 15: 4-93. 5 Esmon CT, Owen WG. Identification of endothelial cell cofactor for thrombin-catalyzed activation of protein C. PYOC Nutl Acail Sci USA 1981; 78: 2249. 6 Suzuki K, Stenflo J, Dahlback B, Teodorsson G. Inactivation of human coagulation factor V by activated protein C. J Biot Ckem
1983; 258: 1914.
Salem HH:, Maruyama I, Ishii H, Majerus PW. Isolation and characteri.zation of thr.ombomodulin from human placenta. J Biol Ckeliz 1984; 259: 12246. 8 Maruyama I, Bell CE, Majerus PW. Thrombomodulin is found on endothelium of arteries, veins, capillaries, and lymphatics, and on syncytiotrophoblast of human placenta. J Cell Biol 1985; 101: 363. 9 Sugiura M, Inagami T, Kon V. Endotoxin stimul.ates endothelin-release in vivo and in vitro as determined by radioimmunoassay. Biockem Biopkys Res Conmun 1989; 161: 7
1220.
10 Morel DR, Lacroix JR, Hemsen A, Steing DA, Pittet JF, Lundberg JM. Increased plasma and pulmonary lymph !evels of endothelin during endotoxin shock. Ew J Pkurmacol
1989; 167: 427.
11 Yoshizumi M, Kurahara M, Morita T. Interleukin-1 increases the production of endothelin-1 by cultured endothelial cells. Biockem Biopkys Res Conzmu~~ 1990; 166: 324.
Wada H, Ohiwa M, Kaneko T et al. Plasma thrombomodulin as a marker of vascular disorders in thrombotic thrombocytopenic purpura and disseminated intravascular coagulation. Am J Henzatol 1992; 39: 20. 14 Ishibashi M, Saito K, Watanabe K, Uesugi S, Furue H. Plasma endothelin-1 levels in patients with disseminated intravascular coagulation. N Erz@ J Med 1991; 324: 1516. 15 Asakura H, Jokaji H, Uotani C et al. Role of endothelin in disseminated intravascular coagulation. Am J Hemat 1992; 13
41: 71. 16
Endo S, Inada K, Kikuchi M et al. Are plasma endotoxin levels related to burn size and prognosis? Burns 1992; 18:
17
Endo S, Inada K, Yamada Y et al. Plasma tumor necrosis factor-r (TNF-r) levels in patients with burns. Burns 1993;
486.
19: 124.
18 Nakae H, Endo S, Inada K et al. Plasma concentrations of type II phospholipase A,, and eicosanoids in patients with burns. Bums 1995; 21: 422. 19 Ando K, Hirata Y, Shichiri M, Marumo F. Presence of immunoreactive endothelin in. human plasma. FEBS Lett 1989;
245: 164.
Kodama S, Uchijima E, Nagai M e: al. One-step sandwich enzyme immunoassay for soluble human thrombomodulin using monoclonal antibodies. Clin Ckim Acta 1990; 192: 191. 21 Kanus WA, Draper EA, WAgner DP, Zimmerman JE. APACHE II: a severity of disease classification. Cvit Care Med 1985; 818. 22 Bevilacqua Ml?, Pober JS, Majeau GR et al. Recombinant tumor necrosis factor induces procoagulant activity in cultured human vascular endothelium: characterization and comparison with the actions of interleukin-1. Proc Nat1 Acad Sci USA 1986; 83: 4533. 20
Paper accepted 24 May 1996. Correspondence should be addressed to: Hajime Nakae, Critical Care and Emergency Center, Iwate Medical University, 19-1 Uchimaru, Morioka 020, Japan.
0 1996 Elsevier
Burns Vol. 22,. No. 8, pp. 594-597, 1996 Science Ltd for ISBI. Ali rights reserved Printed in Great Britain '1305-4179/96
ELSEVIER
PII: SO30541
79(96)00063-O
levels of endothelin-I in burn patients H. Nakae’,
Plasma concentrations of endothelin-1 (ET-l) and tkrombomodulin (TM) were determined in patients with burns to examine their relation to tke severity of illness. Tumor necrosis factor-a (TN&) was also measured, and its relationship to ET-l and TM determined. Twenty-three burn patients were evaluated, who had a total burn surfacearea (TBSA) of at least 20 per cent. ET-l was measured by radioimmunoassay (RIA). TM and TN.&z were measured by enzyme-linked immunosorbenf assay (ELISA). Both the ET-1 and TM concentrations were significantly higher in the patients wko developed sepsis than in those who did not and in the patients who eventually died than in those who survived. Maximum plasma concentrations of ET-l and TM were signiJicantly correlated with the acute physiological and chronic health evaluation 11 score. There was also a significant correlation between the plasma levels of TNF-a and both ET-1 and TM. ET-l and TM closely reflect the severity of illness in patients with burns in the infectious stage; TNT-a may be involved in the production of ET-:! and TM. Copyright 0 1996 Elsevier Science Ltd for ISBI.
Burns, Vol. 22, No. 8,594~.597,1996
Introductian Endothelin-1 (ET-l), a vasoconstrictive peptide, was first found as a secretion product of cultured swine vascular endothelial cells, has a variety of biological activities in addition to vasoconstriction1-4. Thrombomodulin (TM), a protein found in the membrane of the vascular endothelial cell, is a thrombin receptor and, when activated, exerts an antithrombotic effecP Endotoxins and cytokines stimulate the vascular endothelial cells to produce ET-1 and TM9-I’. Blood concentrations of ET-1 and TM are also increased in patients with disseminated intravascular coagulation (DIC)12-1j. A correlation between endotoxin, tumor necrosis factor-a (TNF-c() and the pathological condition of patients with burns has been previously described16-18. In this study, the relationship of ET-1 and TM to burn severity and TNF-a was examined.
Informed obtained
and thrombomodulin
S. Endo’, K. Inada”, Y. Yamadal, ‘T. Takakuwa’
‘Critical Care and Emergencv Center and ZDenartment I Ywate Life Science Insti&te,‘Morioka, Japan
Materials
$15.00+0.00
and methods consent for participation in this study was from the patients or their families, The
of Bacteriology,
and M. Yoshida” Iwate Medical
University
and
study was approved by the Ethics Committee of Iwate Medical University. Twenty-three patients, who had burns over dt least 20 per cent of their body surface and who survived more than 1 week after sustaining the burns, were studied. There were 10 men and 13 women, age range 19-76 years (mean 52.0 k7.6 years). The total burn surface area (TBSA) ranged from 22 to 98 per cent (50.2 +20.4 per cent). Of the 23 patients, 13 survived and 10 eventually died. Fifteen patients developed sepsis during the course of their illness. Serial blood sampling was begun immediately after burns were sustained and was continued until the syrnptoms improved or the patient died. For the ET-1 and TM assays, blood was collected in a trasilol-containing ethylendiaminetetraacetic acid (EDTA) tube and immediately centrifuged at 3000 rprn for 15 min at 4°C to obtain plasma. The plasma was stored at -80°C until assayed. Plasma levels of ET-1 were measured by radioimmunoassay (RIA)19. The normal range was 1.45-3.03 pg/ml. TM levels were determined by enzyme-linked immunosorbent assay (ELISA) (Fuji Pharmaceutical Corp., Tokyo, Japan)2O. A level of 4.5 q/ml or less was regarded as normal. TNF-a levels were also determined by ELISA (Medogenix, Fleurus, Belgium). The limit of detection was 3 pg/ml. The acute physiology and chronic health evaluation II score (APACHE II score)21 was used as an index of the severity of the illness. Data were expressed as mean ) standard deviation. Differences were analysed with. the unpaired Wilcoxon test. Pearson’s formula was used to evaluate correlations. P values CO.05 were considered to be statistically significant.
Results The TBSA values in the surviving group (33.2 _+12.3%) were significantly lower than those in the non-surviving groups (65.9 -t 18.2%) (P = 0.0002). The TBSA value in patients with sepsis (59.1+ 18.8%) was significantly higher than the corresponding value (33.5 _+10.4%) in patients without sepsis (P = 0.0006). In the early stages after the burns were sustained, little increase was seen in the levels of ET-l or TM.
Nakae et al.: Plasma levels of endothelin-1
p-O.0422
I e
0
595
and thrombomodulin
15
.
. :. T
.
10 0.
-+
8 -
!
. .
i 8
n=23 r=0.8341 p<0.0001
5
sepsis (3
sepsis (+I (n=15)
(n::%)
iurvivors (n=l3)
Ncnsurvivors
Figure 3. Correlation and the accompanying
(n=lO)
Figure 1. The serum level of ET-1 in patients with and without sepsis and in surviving and non-surviving patients. Horizontal bars indicate mean values. Increases in ET-l (data not shown).
and TM were The average
triggered maximum
by infection
ET-1 level was 7.4k3.0 pg/ml in all patients. In patients with sepsis, the maximum ET-1 level was 8.4 + 3.0 pgknl, a value significantly higher than the 5.6 k2.0 pg/ml in those without sepsis (Figure 1). The maximum ET-1 level in the non-surviving group was 8.6k3.0 pg/ml, significantly higher than the 6.6 f2.8 pg/ml in the surviving group (Figure 1). The average maximum TM level was 6.6 +2.9 q/ml in all patients. The maximum TM levels in patients with and without sepsiswere 7.7) 2.7 rig/ml and 4.5 _+1.3 rig/ml, respectively (P = 0.0159) (Figure 2). The corresponding level in the surviving group was 5.6f2.3 @ml and in the non-surviving group, 7.9f2.9 @ml (P=O.O493) (Figure 2). The maximum ET-l level was significantly correlated with the maxi.mum TM level (r=0.8341; P
p=o.o493
p=o.o159
endothelin-
0
20
10
0
1 (pg/mL)
between the maximum TM levels.
ET-1 levels
with the TBSA value (r =0.6980; P=O.O002), and the maximum TM level with the TBSA value (u= 0.7752; P < 0.0001). There was a significant correlation between the maximum ET-l level and the “accompanying TNF-a level (Figure 4). A significant correlation was also found between the maximum TM level and the accompanying TNF-a level (Figt~re 5). The maximum TNF-c( level and the TBSA value were significantly correlated with each other (Y= 0.4268; P = 0.0423). The maximum APACHE II score averaged 25.4-L-7.5 in all patients. The ma,ximum APACHE II score was 22.2f6.6 in the surviving group and 29.5 &-6.8 in the non-surviving group, with the latter being significantly higher than the former (P=O.O178). In addition, the average maximum APACHE II score was 27.817.2 in patients with sepsis, significantly higher than the 20.9 i 6.0 in those without sepsis(P = 0.0337). There was a significant correlation between the maximum APACHE II score and the maximum ET-l level (r=0.6974; P= 0.0002) (Figure 6). The maximum APACHE II score was also significantly correlated with the maximum TM level (Y = 0.6779; P =0.0004) (Figure 7) and with the TBSA value (Y= 0.6799; P = 0.0004).
15
.
. ! -
t
0 . .
10
5
. p=O.O062
sepsis (-1 sepsis I+) (n=8) (n=l5)
Survivors (n=l3)
CXkSUViVOl
lb2
(n=lO)
Figure 2. The serum level of TM in the septic, non-septic, surviving and non-surviving patients. Horizontal bars indicate mean values.
lb3
TNF- a (wjnb) Figure 4. Correlation and the accompanying
between the maximum TNF-c( levels.
ET-l
levels
Burns: Vol. 22, No. 8,1996
596
50]
,
a
10 2
lb2
lb3
TNF-a Figure
.
n=23 r=0.5356 p=O.O084
l
r=0.6779
thrombomodulin
(pg/mL)
5. Correlation between the TM
5
10
1 13
(ng/mL)
7. Correlation between the TM levels and the accompanying APACHE II score. Figure
levels and the
accompanying T’NF-a levels.
Discussion Inflammation in the burn patient is assumed to be most severe immediately after the injury. The inflammatory reaction is thought to be at a maximum when. TBSA is most pronounced. It was previously reported that endotoxin and TNF-x are not markedly elevated in the plasma of patients in the early stage of burns and that their concentrations are not correlated with TBSA’“,“. The present results revealed that ET-1 and TM were not markedly elevated, and that neither of them was correlated with TBSA. That is, plasma levels of ET-1 and TM appeared to be independent of the severity of inflammation in the early stages of injury. However, ET-1 and TM were significantly correlated with TRSA throughout the course of the disease, and their levels were significantly higher in the group with associated sepsis than in the group without sepsis. Plasma levels of ET-1 and TM were also significantly higher in the non-surviving group than in the surviving group, and ET-l and TM levels were significantly correlated with the APACHE II score. The chance of infection is thought to be at a maximum when burn size is most pronounced, and morbidity is most severe. ET-1 and TM could not
r =0.6974 p=o.o002 n=23
simply be sophisticated measurements of burn size, because they were not correlated with TBSA in the non-infection period. Thus, ET-I and TM levels appeared to closely parallel the degree of inflammation in the infection period and severity of morbidity related to burns. ET-1 is a vasoconstrictor peptide with other bioactivities and is believed to be involved in the onset of DIC when produced in excess by vascular endothelial cells’4,‘j. TM is a membrane protein that exerts an antithrombus activity on endothelial cells; elevated plasma levels of TM reflect the degree of endothelial cytotoxicity. Some reports have shown that endotoxins or cytokines, which are important in sepsis and septic shock, stimulate the vascular enidothelial cells to produce ET-1 and TM”“. In particular, the production of TM b:y endothelial cells is increased about 40 per cent by TNFP, most likely due to the release of TM from the cell membranes as a result of endothelial cytotoxicity of TNF-a. In this study, the level of TNF-m produced by infectious stimulation was significantly correlated with ET-1 and TM levels, suggesting that TNF-c( stimulates ET-1 and TM production by vascular endothelial cells. ET-1 and TM levels were significantly correlated, probably because levels of both factors closely parallel the severity of vascular cytotoxicity due to stimulation by TNF-a. In patients wh.o developed sepsis and multiple organ failure, levels of both ET-1 and TM also tended to be high, these high levels tended to be Iprolonged. These findings are consistent with reports by Asakura et al.12,15, The present findings suggest that ET-1 and TM are intimately involved in the developrnent of morbidity in the infection stage of burn patients, and that their concentrations closely parallel the severity of the pathology.
Acknowledgements 10-1, 0
10
endothelin-
20
1 (pg/mL)
Figure 6. Correlation between the maximum ET-1 levels and the accompanying APACHE JT score.
This research was supported, in part, by grants 01870116, 03670220 and 05770882 from the Ministry of Education, Science and Culture of Japan, from the Marumo Emergency Medicine Research Fund, and from the special research grants for the development
Nakae et al.: Plasma levels of endothelin-1
of characteristic education by School Prornotion Foundation.
and thrombomodulin
the Japan Private -
597 12 Asakura H, Jokaji H, Saito M et al. Plasma levels of soluble thrombomodulin increase in cases of disseminated intravascular coagulation with organ failure. Am J Hevzatol 1991; 38: 281.
References 1 Yanagisawa M, Kurihara H, Kimura S et al. A novel potent vasoconstrictor peptide produced by vascular endothelial cells. Nature 1988; 332: 411. 2 Miyauchi T, Yanagisawa M, Tomizawa T et al. Increased plasma concentrations of endothelin-1 and big endothelin-1 in acute myocardial infarction. Lutz& 1989; ii: 53. 3 Saito Y, Nakao K, Mukoyama M, Imura H. Increased plasma endothelin level in patients with essential hypertension. &’ Exgl J Med 1990; 322: 205. 4 Shichiri M, Hirata Y, Ando K et al. Plasma endothelin levels in hypertension and chronic renal failure. Hypevtensioll 1990; 15: 4-93. 5 Esmon CT, Owen WG. Identification of endothelial cell cofactor for thrombin-catalyzed activation of protein C. PYOC Nutl Acail Sci USA 1981; 78: 2249. 6 Suzuki K, Stenflo J, Dahlback B, Teodorsson G. Inactivation of human coagulation factor V by activated protein C. J Biot Ckem
1983; 258: 1914.
Salem HH:, Maruyama I, Ishii H, Majerus PW. Isolation and characteri.zation of thr.ombomodulin from human placenta. J Biol Ckeliz 1984; 259: 12246. 8 Maruyama I, Bell CE, Majerus PW. Thrombomodulin is found on endothelium of arteries, veins, capillaries, and lymphatics, and on syncytiotrophoblast of human placenta. J Cell Biol 1985; 101: 363. 9 Sugiura M, Inagami T, Kon V. Endotoxin stimul.ates endothelin-release in vivo and in vitro as determined by radioimmunoassay. Biockem Biopkys Res Conmun 1989; 161: 7
1220.
10 Morel DR, Lacroix JR, Hemsen A, Steing DA, Pittet JF, Lundberg JM. Increased plasma and pulmonary lymph !evels of endothelin during endotoxin shock. Ew J Pkurmacol
1989; 167: 427.
11 Yoshizumi M, Kurahara M, Morita T. Interleukin-1 increases the production of endothelin-1 by cultured endothelial cells. Biockem Biopkys Res Conzmu~~ 1990; 166: 324.
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Paper accepted 24 May 1996. Correspondence should be addressed to: Hajime Nakae, Critical Care and Emergency Center, Iwate Medical University, 19-1 Uchimaru, Morioka 020, Japan.