 |
 Previous Article | Next Article 
The Journal of Neuroscience, February 15, 1998, 18(4):1393-1398
Activated Protein C Reduces the Severity of Compression-Induced
Spinal Cord Injury in Rats by Inhibiting Activation of Leukocytes
Yuji
Taoka1, 3,
Kenji
Okajima1,
Mitsuhiro
Uchiba1,
Kazunori
Murakami1,
Naoaki
Harada1,
Masayoshi
Johno2, and
Masakuni
Naruo3
Departments of 1 Laboratory Medicine and
2 Dermatology, Kumamoto University School of Medicine,
Kumamoto, 860, Japan, and 3 Naruo Orthopedic Hospital,
Kumamoto, 860, Japan
 |
ABSTRACT |
Activated protein C (APC), an important inhibitor of the
coagulation system, has recently been shown to prevent tissue injury by
blocking the activation of leukocytes. To determine whether APC can
also prevent post-traumatic spinal cord injury (SCI), a condition in
which leukocytes play an important role, we tested the effects of APC
on SCI induced in rats by compression trauma. Administration of APC,
either before or after the induction of SCI, markedly reduced the motor
disturbances in these animals. In contrast, neither an inactive
derivative of activated factor X (DEGR-Xa), a selective inhibitor of
thrombin generation, nor active site-blocked APC (DIP-APC) reduced the
motor disturbances. Histological examination revealed that
intramedullary hemorrhages, observed 24 hr after trauma, were
significantly reduced in the animals administered APC. The increase in
the tissue level of tumor necrosis factor- (TNF-) and the
accumulation of neutrophils in the damaged segment of the spinal cord
were significantly inhibited in the animals that had received APC, but
these were not inhibited in those administered DIP-APC or DEGR-Xa. The
induction of leukocytopenia had the same effect as APC, in that it
significantly reduced motor disturbances, tissue levels of TNF-, and
neutrophil accumulation in the animals subjected to compressive SCI.
These findings suggest that in SCI, APC reduces motor disturbances
primarily by reducing the amount of TNF- at the site of injury, thus
inhibiting neutrophil accumulation and the resultant damage to the
endothelial cells.
Key words:
activated protein C; post-traumatic spinal cord injury; leukocytes; motor disturbances; TNF-; neutrophils
| |
INTRODUCTION |
Spinal cord injury (SCI) is a
serious condition that produces lifelong disabilities (Stover and Fine,
1987 ). Only limited therapeutic measures are currently available for
its treatment (Bracken et al., 1990). SCI induced by trauma is a
consequence of an initial physical insult that is followed by a
progressive injury process that involves various pathochemical events
that lead to tissue destruction (Young, 1988; Bracken et al., 1990). Therapeutic intervention for SCI should therefore be directed at
reducing or alleviating this secondary process. Although the mechanisms
are not fully understood, progressive vascular events, such as
ischemia/reperfusion-induced endothelial damage, are involved in this
process (Demopoulos et al., 1978; Means and Anderson, 1983; Xu et al.,
1990; Blight, 1992). We have demonstrated that activated neutrophils
are important in inducing the damage to endothelial cells observed in
SCI induced by trauma (Taoka et al., 1997a).
Activated protein C (APC) is an important physiological anticoagulant
that is generated from protein C by the action of the thrombin-thrombomodulin complex on the endothelial cells (Walker et
al., 1979). APC inactivates factors Va and VIIIa, thereby regulating the coagulation system (Walker et al., 1979; Esmon, 1992). APC is also
implicated in the regulation of the inflammatory process by its
inhibition of cytokine production by monocytes (Grey et al., 1993,
1994). We demonstrated previously that APC prevents the injury to
endothelial cells induced by activated leukocytes, primarily by
inhibiting the ability of monocytes to produce tumor necrosis
factor- (TNF-) (Murakami et al., 1996, 1997). Because TNF- is
a potent activator of neutrophils (Klebanoff et al., 1986), it is
possible that APC may also prevent the secondary effects of
trauma-induced SCI by inhibiting neutrophil activation. We therefore
evaluated the effects of APC in a rat model of compression-induced SCI.
| |
MATERIALS AND METHODS |
Reagents. APC was obtained from human
thrombin-activated protein C and purified by cation-exchange
chromatography as described previously (Katsu-ura et al., 1994).
Nitrogen mustard was obtained from Sigma (St. Louis, MO). All other
reagents used were of analytical grade.
Preparation of dansyl glutamyl-glycyl-arginyl chloromethyl
ketone-treated factor Xa. Factor X, purified from human plasma and
activated with Russell's viper venom (Bajaj et al., 1981), was
inactivated by incubation with a 20-fold molar excess of dansyl glutamyl-glycyl-arginyl chloromethyl ketone (DEGR) for 30 min at
25°C, after which the mixture was subjected to extensive dialysis against a solution containing 20 mM Tris-HCl, pH 7.4, and
100 mM NaCl. DEGR-treated factor Xa (DEGR-Xa) has been
shown to selectively inhibit thrombin generation by competing with
intact factor Xa for prothrombinase complex formation (Nesheim et al.,
1981).
Preparation of diisopropyl fluorophosphate-treated APC
(DIP-APC). APC was inactivated with DIP (Sigma) by incubating APC
(1 mg/ml) with 19 mmol/l of DIP in PBS, pH 7.4, for 2 hr and dialyzing it extensively against the same buffer (Grey et al., 1994). The effectiveness of inactivation was monitored amidolytically by measuring
the rate of hydrolysis of the chromogenic substrate S-2366 (Chromogenix
AB, Stockholm, Sweden) at 405 nm. The amount of APC activity remaining
was <1%.
Animal model of spinal cord injury. The study protocol was
approved by the Kumamoto University Animal Care and Use Committee. The
care and handling of the animals were conducted in accordance with the
guidelines of the National Institutes of Health. Under pentobarbital
anesthesia (45 mg/kg, i.p.) (Abbott Laboratories, North Chicago, IL),
adult pathogen-free male Wistar rats (Nihon SLC, Hamamatsu, Japan),
weighing 300-350 gm, were subjected to laminectomy using a surgical
airtome at the level of the 12th thoracic vertebra (Th12). Spinal cord
injury (SCI) was induced by applying a 20 gm weight extradurally to the
spinal cord at Th12 for 20 min as described previously (Taoka et al.,
1997a,b). This technique causes paralysis of the lower extremities in a reproducible manner (Taoka et al., 1995; Hamada et al., 1996). Laminectomy alone was performed as a sham operation. APC (100 µg/kg)
was administered intravenously to rats 30 min before (pretreatment group) or after (post-treatment group) the compressive trauma. DIP-APC
(100 µg/kg) and DEGR-Xa (10 mg/kg) were administered intravenously 30 min before trauma. The control and leukocytopenic animals received saline instead of anticoagulants or other drugs.
Grading of motor disturbance. The motor function of rats was
assessed in a blind manner using the the inclined-plane test (Rivlin
and Tator, 1977) and footprint analysis (Kunkel-Bagden and Bregman,
1993). In the inclined-plane test, recovery from motor disturbance was
assessed before, and again at 1, 7, 14, and 21 d after the
compression. We recorded the maximum inclination of the plane on which
the rats could maintain themselves for 5 sec without falling.
Footprint analysis was performed before and 3 weeks after the
compression injury, as illustrated in Figure
1. The hindpaws were wetted, and the
animals were made to walk on paper coated with bromophenol blue (Wako
Pure Chemical Industries) dissolved in acetone. The base of support was
determined by measuring the distance between the central pads of the
hindpaws (DBF). The stride lengths of the right and left hindpaws (RSL
and LSL) were measured in two consecutive prints.
View larger version (11K):
[in this window]
[in a new window]
|
Figure 1.
Footprint analysis. The base of support
(DBF) and right and left stride lengths
(RSL and LSL) were measured from
footprints.
|
|
Histological examination of the spinal cord. Rats were
killed at random 24 hr after compressive SCI. They were perfused
transcardially with 10% formaldehyde in a phosphate-buffered solution; ~ 1 cm of the spinal cord at Th12 was removed immediately and
immersed overnight in the same solution. Transverse, semi-serial
sections of 5 µm thickness were prepared and embedded in paraffin.
These sections were subsequently stained with hematoxylin and eosin. The samples were assessed by a pathologist who had no knowledge of any
animal's group.
Assay of myeloperoxidase activity. The extent of leukocyte
infiltration was assessed by measurement of myeloperoxidase (MPO) activity (Lundberg and Arfors, 1983) using a modification of a method described previously (Xu et al., 1990). Within 1 hr after the
rats were killed, sections of ~1 cm were dissected from the Th12
region, removed, and placed in ice-cold 0.9% NaCl bath. A 10%
(wt/vol) tissue homogenate was mixed with a 20 mM phosphate buffer, pH 6.0, containing 0.5% hexadecyltrimethyl ammonium bromide (Sigma) and sonicated for 30 sec. After centrifugation (4500 × g at 4°C for 20 min), 0.1 ml of supernatant was added to
0.6 ml of 0.1 M phosphate buffer, pH 6.0, containing 1.25 mg/ml o-dianisidine and 0.05% H2O2. After 5 min, the change in absorbance at 460 nm was measured
spectrophotometrically (DU-54, Beckman, Irvine, CA), and the MPO
activity in each sample was calculated using a standard curve for
purified MPO (Sigma).
Assay of TNF-. The level of TNF- in spinal cord tissue
was determined before and 1, 2, 3, 4, 6, 12, and 24 hr after SCI according to the methods described by Murakami et al. (1997). Briefly,
within 1 hr after the rats were killed, sections from the Th12 region
measuring ~1 cm were dissected, removed, and placed in ice-cold 0.9%
NaCl. A 20% (wt/vol) tissue homogenate was mixed with a 0.1 M phosphate buffer, pH 7.4, sonicated for 30 sec, and centrifuged at 4500 × g for 20 min at 4°C. The
concentration of TNF- in the supernatant was determined using an
enzyme-linked immunosorbent assay (ELISA) kit for rat TNF- (Genzyme
Corporation, Cambridge, MA). Results are expressed as picograms of
TNF- per gram of tissue.
Induction of leukocytopenia by nitrogen mustard. Rats were
made leukocytopenic by the intravenous injection of nitrogen mustard (NM) (Müller-Berghaus and Eckhart, 1975). Because the dose of NM
of 1.75 mg/kg administered in an earlier study had caused death in all
rats within 10 d of laminectomy, probably as a result of infection
(Taoka et al., 1997b), we now administered an intravenous dose of 1.0 mg/kg. This dose caused no deaths for 3 weeks after SCI. NM or 0.9%
NaCl was administered intravenously to rats 2 d before induction
of SCI. The circulating leukocyte count on day 0 was 9375 ± 1365/µl (n = 10) in controls and 3350 ± 230/µl in NM-treated rats (n = 10)
(p < 0.01). In differential leukocyte counts
made on peripheral blood smears, the number of neutrophils counts on
day 0 was 1298 ± 428/µl in controls and 733 ± 112/µl in
NM-treated rats (p < 0.01), and the number of
monocytes was 539 ± 286/µl in controls and 182 ± 38/µl
in NM-treated animals (p < 0.01).
Statistical analysis. Data are presented as the mean ± SD. Circulating leukocyte counts were compared using Student's
t test. Statistical comparisons of the mean degrees in the
inclined-plane test, mean distance between feet, mean stride length,
mean MPO activity, and the mean TNF- level between groups used the
ANOVA and Scheffe's post hoc test. A level of
p < 0.05 was defined as statistically significant.
| |
RESULTS |
Effect of APC on SCI induced by compression trauma
As reported previously (Hamada et al., 1996), we found that when
evaluated by the inclined-plane test, motor disturbances were increased
within 24 hr of the compressive SCI. After 24 hr, the neurological
scores were significantly higher in the rats treated with APC before
the induction of SCI versus that of the controls (Figs.
2, 3). From
1 to 21 d after the induction of SCI, the angle of the inclined
plane was significantly higher in the rats pretreated with APC than in
the controls (Fig. 2).
View larger version (17K):
[in this window]
[in a new window]
|
Figure 2.
Temporal effect of pretreatment with APC on motor
disturbances after compressive SCI. Spinal cord injury was induced by
applying a 20 gm weight for 20 min at Th12, and motor disturbances of
the hindlimbs were evaluated after SCI using an inclined-plane test. APC (100 µg/kg) or buffer (as a control) was administered
intravenously 30 min before injury. Closed circles,
Traumatized animals; open circles, APC-treated animals.
Mean ± SD of 10 experiments. *p < 0.01 versus traumatized animals.
|
|
View larger version (20K):
[in this window]
[in a new window]
|
Figure 3.
Effects of APC, DEGR-Xa, NM-induced
leukocytopenia, and DIP-APC on motor disturbances 1 d after
induction of SCI as determined by an inclined-plane test. Motor
disturbances of the hindlimbs were evaluated 1 d later using an
inclined-plane test. APC (100 µg/kg), DIP-APC (100 µg/kg), DEGR-Xa
(10 mg/kg), or buffer (as a control) was administered intravenously 30 min before injury, or APC was administered 30 min after injury.
Leukocytes were depleted by administration of nitrogen mustard (NM).
Mean ± SD of 10 experiments. *p < 0.05 versus
Trauma.
|
|
The administration of APC after trauma also significantly improved the
motor function of rats. Whether evaluated by the inclined-plane test
(Figs. 3, 4A) or
footprint analysis (Fig. 4B,C), the neurological scores 1 and 21 d after the induction of SCI were higher in the rats administered APC post-traumatically than in controls.
View larger version (27K):
[in this window]
[in a new window]
|
Figure 4.
Effects of APC, DEGR-Xa, NM-induced
leukocytopenia, and DIP-APC on motor disturbances 21 d after
induction of SCI as determined by an inclined-plane test and footprint
analysis. Motor disturbances of the hindlimbs were evaluated 21 d
after induction of SCI using the inclined-plane test and footprint
analysis. Concentrations of APC, DEGR-Xa, NM, and DIP-APC were as in
Figure 3. Mean ± SD of 10 experiments. *p < 0.01 versus Trauma.
|
|
In contrast to APC, neither DEGR-Xa (a selective inhibitor of thrombin
generation) nor DIP-APC (active site-blocked APC) had any effect on the
motor function of rats 1 and 21 d after the injury to the spinal
cord (Figs. 3, 4).
Histological observations
Histological examination of the traumatized spinal cord 24 hr
after the induction of SCI showed the presence of intramedullary hemorrhages in control animals (Fig. 5).
These hemorrhages were observed more often in the gray than in the
white matter. In contrast, there was markedly less hemorrhage in the
animals that had received APC before trauma (Fig. 5). Neither DEGR-Xa
nor DIP-APC prevented hemorrhagic changes in the injured spinal cord
(data not shown).
View larger version (84K):
[in this window]
[in a new window]
|
Figure 5.
Histology of (A) an intact
spinal cord section and in traumatized spinal cord sections from the
level of the 12th thoracic vertebra in rats that received
(B) saline or (C) APC
(150×, hematoxylin and eosin). Five animals in each group were
examined; typical results are shown.
|
|
Effect of APC on increase in MPO activity induced by trauma
The accumulation of neutrophils at the traumatized spinal cord
tissue was evaluated by measuring MPO activity 3 hr after the induction
of compressive trauma. The increase in MPO activity, observed in
traumatized animals versus sham-operated rats, was inhibited
significantly in the spinal cord of animals that received APC 30 min
before trauma (Fig.
6A). The administration
of DEGR-Xa or DIP-APC did not inhibit this increased MPO activity (Fig.
6A).
View larger version (26K):
[in this window]
[in a new window]
|
Figure 6.
Effects of APC, DEGR-Xa, NM-induced
leukocytopenia, and DIP-APC on (A) MPO activity
and (B) TNF- levels in traumatized spinal cord. MPO activity and TNF- level at Th12 were measured 3 or 4 hr
after compressive trauma or a sham-operation, respectively. Mean ± SD of five experiments.  p < 0.05 versus
Trauma; *p < 0.01 versus
Trauma.
|
|
Effects of APC and nitrogen mustard-induced leukocytopenia on
increased TNF- in injured segment of spinal cord
After the induction of SCI at Th12, we measured the level of
TNF- in this segment over time. The tissue level of TNF-
increased significantly within 1 hr and peaked at 4 hr (Fig.
7). The tissue level of TNF- 1-6 hr
after trauma significantly exceeded that of sham-operated animals (Fig.
7).
View larger version (15K):
[in this window]
[in a new window]
|
Figure 7.
Changes in TNF- level at Th12 over time after
compressive trauma or a sham-operation. TNF- levels at Th12 were
measured before and after the induction of compressive trauma or
sham-operation. Closed circles, Traumatized animals;
open circles, sham-operated animals. Mean ± SD of
five experiments. p < 0.05 versus sham-operated group; *p < 0.01 versus sham-operated group.
|
|
When we evaluated the effect of APC on tissue levels of TNF- 4 hr
after induction of trauma, we found that APC significantly inhibited
the compression-induced increases in TNF- (Fig.
6B). The animals administered nitrogen mustard to
induce leukocytopenia also showed greatly reduced levels of TNF-
(Fig. 6B). In contrast, neither DEGR-Xa nor DIP-APC
had any effect on TNF- level in animals with SCI (Fig.
6B).
| |
DISCUSSION |
We observed that APC significantly reduced the deleterious effects
of SCI in rats. When administered before or after the induction of
trauma, APC reduced the number of intramedullary hemorrhages as well as
the severity of motor disturbances. Although the motor disturbances
evaluated by using the inclined-plane test were not completely
recovered 42 d after trauma, those in animals given APC before or
after the trauma were recovered 35 d after trauma (data not
shown), suggesting that APC might promote the functional recovery of
the motor disturbances in this animal model of spinal cord injury.
Because APC inhibited at the active site (DIP-APC) and a selective
inhibitor of thrombin generation (DEGR-Xa) had no effect, our results
with APC suggest that the efficacy of this protein may not be mediated
by inhibition of thrombin generation. However, this observation does
not exclude the possibility that APC may attenuate the spinal cord
injury by inactivation of factor Va/VIIIa.
The accumulation of neutrophils in traumatized segments of the spinal
cord as reflected by tissue MPO activity was also significantly inhibited in animals treated with APC. The leukocytopenia induced by NM
markedly reduced the motor disturbances as well as accumulation of
neutrophils in traumatized spinal cord tissue, suggesting that the
accumulation of neutrophils may not be an effect but rather may be a
cause of the motor disturbances observed after SCI induced by
compression trauma. Because DIP-APC did not prevent the accumulation of
neutrophils at the injured site, the inhibition of neutrophil accumulation by APC may also be mediated by its serine protease activity. This is consistent with our previous observation that APC
prevents endotoxin-induced lung injury by inhibiting the accumulation of neutrophils, and that this effect is also dependent on the serine
protease activity of APC (Murakami et al., 1996, 1997).
Although we observed the accumulation of neutrophils at the traumatized
site, we found no histological evidence of their infiltration into the
tissue of the injured spinal cord (Taoka et al., 1997a). This suggests
that neutrophils may accumulate at the endothelial surface, where they
may damage the endothelial cells by releasing a wide variety of
inflammatory mediators such as granulocyte elastase and oxygen free
radicals (Harlan, 1987; Carlos and Harlan, 1994). Indeed, our
preliminary study indicates that L-658,758, a specific granulocyte
elastase inhibitor (Zimmerman and Granger, 1990), prevents the SCI
induced by compressive trauma in this animal model (our unpublished
data).
Our results strongly suggest that the production of TNF- at the site
of SCI is implicated in the secondary damage to tissue in SCI. We found
that the level of this protein in the traumatized spinal cord tissue
was significantly increased after compressive trauma, with a peak seen
after 4 hr. These results are consistent with those of other
researchers. For example, Wang et al. (1996) showed the presence of
TNF- at the sites of traumatic spinal cord lesions but did not
detect this factor in cerebrospinal fluid or in serum. In addition,
Yakovlev and Faden (1994) demonstrated that spinal cord impact in rats
caused an elevation of TNF- mRNA levels at the site of trauma 30 min
after the injury; the severity of injury was proportional to the level
of the TNF- message. Our additional observation, that leukocytopenic
rats in which the level of TNF- was not increased at the site of
trauma exhibited a significant reduction in motor disturbances,
indicates that increased levels of TNF- at the site of injury may be
a cause, rather than an effect, of the SCI induced by compressive
trauma.
TNF- contributes to the tissue injury induced by neutrophils by
directly activating them (Klebanoff et al., 1986), as well as by
increasing the expression of such molecules as E-selectin, which cause
the activated neutrophils to adhere to the surface of the endothelial
cells (Mulligan et al., 1991). We have also shown that the inhibition
of neutrophil adhesion to the endothelial cell surface markedly reduces
the severity of the SCI induced by compressive trauma (Taoka et al.,
1997a). These observations indicate that the interaction of activated
neutrophils with the surface of the endothelial cells is important in
the secondary tissue damage that occurs after SCI. Because no increase
in the level of TNF- induced by SCI was found in the animals that
had received APC, this suggests that APC may inhibit the accumulation of neutrophils at the site of the traumatic spinal cord injury primarily by inhibiting TNF- production. This is supported by our
earlier findings; i.e., that APC also inhibits the in vivo and in vitro production of TNF- by monocytes, that this
activity depends on the serine protease activity of APC, and that APC
does not directly inhibit the neutrophils (Murakami et al., 1997).
Although the precise mechanism(s) by which APC inhibits the production
of TNF- has not been fully elucidated, our finding that DIP-APC did
not affect the level of TNF- at the site of trauma suggests that the
serine protease activity of APC may be important in the inhibition of
TNF- production. Grey et al. (1993, 1994) also reported that APC
suppresses the production of TNF- by LPS-stimulated monocytes by
inhibiting the coupling of LPS and CD14, but that DIP-APC did not
possess this activity. In contrast, however, Grinnell et al. (1994)
demonstrated that the inhibition of neutrophil accumulation by APC was
not related to the serine protease activity of APC, because the
carbohydrate moieties of APC reacted more with E-selectin than with the
sialyl Lewis X antigen of neutrophils. This possibility, however, seems
less likely in vivo, because we found that DIP-APC did not
reduce the accumulation of neutrophils at the traumatized site.
We have demonstrated that APC can lessen the severity of the SCI
induced by trauma by inhibiting the accumulation of neutrophils and the
production of TNF-. Because the administration of APC after the
injury was as effective as its administration before injury in
preventing the secondary effects of SCI, APC may have a potential for
clinical use in alleviating the effects of traumatic compression injury
to the spinal cord.
| |
FOOTNOTES |
Received Aug. 8, 1997; revised Nov. 26, 1997; accepted Dec. 2, 1997.
Correspondence should be addressed to Dr. Kenji Okajima, Department of
Laboratory Medicine, Kumamoto University School of Medicine, Honjo
1-1-1, Kumamoto 860, Japan.
| |
REFERENCES |
-
Bajaj SP,
Rapaport SI,
Prodanos CA
(1981)
A simplified procedure for purification of human prothrombin, factor IX and factor X.
Prep Biochem
11:397-412[ISI][Medline].
-
Blight AR
(1992)
Macrophages and inflammatory damage in spinal cord injury.
J Neurotrauma
9:S83-S91.
-
Bracken MB,
Shepard MJ,
Collins WF,
Holord TR,
Young W,
Baskin DS,
Eisenberg HM,
Flamm E,
Leo-Summers L,
Maroon J,
Maeshall LF,
Perot PL,
Piepmeier J,
Sonntag KH,
Wagner FC,
Wilberger JE,
Winn HR
(1990)
A randomized, controlled trial of methylprednisolone or naloxone in the treatment of acute spinal-cord injury.
New Engl J Med
322:1405-1411[Abstract].
-
Carlos TM,
Harlan JM
(1994)
Leukocyte-endothelial adhesion molecules.
Blood
84:2068-2101[Abstract/Free Full Text].
-
Demopoulos HB,
Yoder M,
Gutman EG,
Seligman ML,
Flamm ES,
Ransohoff J
(1978)
The fine structure of endothelial surfaces in the microcirculation of experimentally injured feline spinal cords.
Scan Electron Microsc
2:677-680.
-
Esmon CT
(1992)
The protein C anticoagulant pathway.
Arterioscler Thromb
12:135-145[Free Full Text].
-
Grey S,
Hau H,
Salem HH,
Hancock WW
(1993)
Selective effects of protein C on activation of human monocytes by lipopolysaccharide, interferon-g, or PMA: modulation of effects on CD11b and CD14 but not CD25 or CD54 induction.
Transplant Proc
25:2913-2914[ISI][Medline].
-
Grey ST,
Tsuchida A,
Hau H,
Orthner CL,
Salem HH,
Hancock WW
(1994)
Selective inhibitory effects of the anticoagulant activated protein C on the ponses of human mononuclear phagocytes to LPS, IFN-g, or phorbolester.
J Immunol
153:3664-3672[Abstract].
-
Grinnell BW,
Hermann RB,
Yan SB
(1994)
Human protein C inhibits selectin-mediated cell adhesion: role of unique fucosylated oligosaccharide.
Glycobiology
4:221-225[Abstract/Free Full Text].
-
Hamada Y,
Ikata T,
Katoh S,
Nakauchi K,
Niwa M,
Kawai Y,
Fukuzawa K
(1996)
Involvement of an intracellular adhesion molecule 1-dependent pathway in the pathogenesis of secondary changes after spinal cord injury in rats.
J Neurochem
66:1525-1531[ISI][Medline].
-
Harlan JM
(1987)
Consequences of leukocytes-vessel wall interactions in inflammatory and immune reactions.
Semin Thromb Hemost
13:425-433[ISI][Medline].
-
Katsu-ura Y K,
Aoki H,
Tanabe M,
Funatsu A
(1994)
Characteristic effects of activated human protein C on tissue thromboplastin-induced disseminated intravascular coagulation in rabbits.
Thromb Res
76:353-357[ISI][Medline].
-
Klebanoff SJ,
Vadas MA,
Harlan JM
(1986)
Stimulation of neutrophils by tumor necrosis factor.
J Immunol
136:4220-4225[Abstract].
-
Kunkel-Bagden E,
Bregman BS
(1993)
Methods to assess the development and recovery of locomotor function after spinal cord injury in rats.
Exp Neurol
119:153-164[ISI][Medline].
-
Lundberg C,
Arfors K
(1983)
Polymorphonuclear leukocyte accumulation in inflammatory dermal sites as measured by 51Cr-labeled cells and myeloperoxidase.
Inflammation
7:247-255[ISI][Medline].
-
Means ED,
Anderson DK
(1983)
Neuronophagia by leukocytes in experimental spinal cord injury.
J Neuropathol Exp Neurol
42:707-719[ISI][Medline].
-
Müller-Berghaus G,
Eckhart T
(1975)
The role of granulocytes in the activation of intravascular coagulation and the precipitation of soluble fibrin by endotoxin.
Blood
45:631-641[Abstract/Free Full Text].
-
Mulligan MS,
Varani J,
Dame MK
(1991)
Role of endothelial-leukocyte adhesion molecule 1 (ELAM-1) in neutrophil-mediated lung injury in rats.
J Clin Invest
88:1396-1406.
-
Murakami K,
Okajima K,
Uchiba M,
Johno M,
Nakagaki T,
Okabe H,
Takatsuki K
(1996)
Activated protein C attenuates endotoxin-induced pulmonary vascular injury by inhibiting activated leukocytes in rats.
Blood
87:642-647[Abstract/Free Full Text].
-
Murakami K,
Okajima K,
Uchiba M,
Johno M,
Nakagaki T,
Okabe H,
Takatsuki K
(1997)
Activated protein C prevents LPS-induced pulmonary vascular injury by inhibiting cytokine production.
Am J Physiol
272:L197-L202[Abstract/Free Full Text].
-
Nesheim ME,
Kettner C,
Shaw E,
Mann KG
(1981)
Cofactor dependence of factor Xa incorporation into the prothrombinase complex.
J Biol Chem
256:6537-6540[Abstract/Free Full Text].
-
Rivlin AS,
Tator CH
(1977)
Objective clinical assessment of motor function after experimental spinal cord injury in the rat.
J Neurosurg
47:577-581[ISI][Medline].
-
Stover SL,
Fine PR
(1987)
The epidemiology and economics of spinal cord injury.
Paraplegia
24:225-228.
-
Taoka Y,
Naruo M,
Koyanabi E,
Urakado M,
Inoue M
(1995)
Superoxide radicals play important roles in the pathogenesis of spinal cord injury.
Paraplegia
33:450-453[ISI][Medline].
-
Taoka Y,
Okajima K,
Uchiba M,
Murakami K,
Kushimoto S,
Johno M,
Naruo M,
Okabe H,
Takatsuki K
(1997a)
Role of neutrophils in spinal cord injury in the rat.
Neuroscience
79:1177-1182[ISI][Medline].
-
Taoka Y,
Okajima K,
Uchiba M,
Murakami K,
Kushimoto S,
Johno M,
Naruo M,
Okabe H,
Takatsuki K
(1997b)
Reduction of spinal cord injury by administration of iloprost, a stable prostacyclin analog.
J Neurosurg
86:1007-1011[ISI][Medline].
-
Walker FJ,
Sexton PW,
Esmon CT
(1979)
The inhibition of blood coagulation by activated protein C through the selective inactivation of activated factor V.
Biochim Biophys Acta
571:333-342[Medline].
-
Wang CX,
Nuttin B,
Heremans H,
Gybels R
(1996)
Production of tumor necrosis factor in spinal cord following traumatic injury in rats.
J Neuroimmunol
89:151-156.
-
Xu J,
Hsu CY,
Liu TH,
Hogan EL,
Perot E,
Tai H
(1990)
Leukotriene B4 release and polymorphonuclear cell infiltration in spinal cord injury.
J Neurochem
55:907-912[ISI][Medline].
-
Yakovlev AG,
Faden AI
(1994)
Sequential expression of c-fos protooncogene, TNF-alpha, and dynorphin genes in spinal cord following experimental traumatic injury.
Mol Chem Neuropathol
23:179-190[ISI][Medline].
-
Young W
(1988)
Secondary CNS injury.
J Neurotrauma
5:219-221[Medline].
-
Zimmerman BJ,
Granger DN
(1990)
Reperfusion-induced leukocyte infiltration: role of elastase.
Am J Physiol
259:H390-H394[Abstract/Free Full Text].
Copyright © 1998 Society for Neuroscience 0270-6474/98/1841393-06$05.00/0
This article has been cited by other articles:
|
|
|
|
 
A. Mizutani, P. Enkhbaatar, A. Esechie, L. D. Traber, R. A. Cox, H. K. Hawkins, D. J. Deyo, K. Murakami, T. Noguchi, and D. L. Traber
Pulmonary changes in a mouse model of combined burn and smoke inhalation-induced injury
J Appl Physiol,
August 1, 2008;
105(2):
678 - 684.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
L. O. Mosnier, B. V. Zlokovic, and J. H. Griffin
The cytoprotective protein C pathway
Blood,
April 15, 2007;
109(8):
3161 - 3172.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Weijer, C. W. Wieland, S. Florquin, and T. van der Poll
A thrombomodulin mutation that impairs activated protein C generation results in uncontrolled lung inflammation during murine tuberculosis
Blood,
October 15, 2005;
106(8):
2761 - 2768.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Adrie, M. Monchi, I. Laurent, S. Um, S. B. Yan, M. Thuong, A. Cariou, J. Charpentier, and J. F. Dhainaut
Coagulopathy After Successful Cardiopulmonary Resuscitation Following Cardiac Arrest: Implication of the Protein C Anticoagulant Pathway
J. Am. Coll. Cardiol.,
July 5, 2005;
46(1):
21 - 28.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Uchiba, K. Okajima, Y. Oike, Y. Ito, K. Fukudome, H. Isobe, and T. Suda
Activated Protein C Induces Endothelial Cell Proliferation by Mitogen-Activated Protein Kinase Activation In Vitro and Angiogenesis In Vivo
Circ. Res.,
July 9, 2004;
95(1):
34 - 41.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. W. Rijneveld, S. Weijer, S. Florquin, C. T. Esmon, J. C. M. Meijers, P. Speelman, P. H. Reitsma, H. Ten Cate, and T. van der Poll
Thrombomodulin mutant mice with a strongly reduced capacity to generate activated protein C have an unaltered pulmonary immune response to respiratory pathogens and lipopolysaccharide
Blood,
March 1, 2004;
103(5):
1702 - 1709.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Levi, T. T Keller, E. van Gorp, and H. ten Cate
Infection and inflammation and the coagulation system
Cardiovasc Res,
October 15, 2003;
60(1):
26 - 39.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. T. Esmon
Coagulation and inflammation
Innate Immunity,
June 1, 2003;
9(3):
192 - 198.
[Abstract]
[PDF]
|
|
|
|
|
|
|
A. Mizutani, K. Okajima, M. Uchiba, H. Isobe, N. Harada, S. Mizutani, and T. Noguchi
Antithrombin reduces ischemia/reperfusion-induced renal injury in rats by inhibiting leukocyte activation through promotion of prostacyclin production
Blood,
April 15, 2003;
101(8):
3029 - 3036.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
H. Weiler, V. Lindner, B. Kerlin, B. H. Isermann, S. B. Hendrickson, B. C. Cooley, D. A. Meh, M. W. Mosesson, N. W. Shworak, M. J. Post, et al.
Characterization of a Mouse Model for Thrombomodulin Deficiency
Arterioscler. Thromb. Vasc. Biol.,
September 1, 2001;
21(9):
1531 - 1537.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Mizutani, K. Okajima, M. Uchiba, and T. Noguchi
Activated protein C reduces ischemia/reperfusion-induced renal injury in rats by inhibiting leukocyte activation
Blood,
June 15, 2000;
95(12):
3781 - 3787.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
F. B. Taylor Jr, D. J. Stearns-Kurosawa, S. Kurosawa, G. Ferrell, A. C. K. Chang, Z. Laszik, S. Kosanke, G. Peer, and C. T. Esmon
The endothelial cell protein C receptor aids in host defense against Escherichia coli sepsis
Blood,
March 1, 2000;
95(5):
1680 - 1686.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
Top
Abstract
Introduction
