Statins inhibit Rho kinase activity in patients with atherosclerosis.
ABSTRACT In addition to inhibiting cholesterol synthesis, statins (HMG-CoA reductase inhibitors) decrease the formation of isoprenoid intermediates required for the activation of key signaling pathways, including Rho/Rho kinase (ROCK). In experimental settings, statins inhibit ROCK and reverse vascular dysfunctions in atherosclerosis, independent of cholesterol reduction. It is not known whether statins inhibit ROCK activity in humans with atherosclerosis.
We investigated 35 patients with stable atherosclerosis in a randomized, double-blind study comparing treatment with high-dose (80mg/d) or low-dose (10mg/d) atorvastatin to placebo for 28 days. Blood samples for leukocyte ROCK activity, fasting lipids, and high-sensitivity C-reactive protein (hs-CRP) were obtained on days 0, 7, 14, and 28 after randomization and change over time with the two statin treatments relative to placebo was examined.
Atorvastatin 80mg/d reduced ROCK activity (p=0.002 vs. placebo). This decline was rapid and significant within 2 weeks of treatment. The inhibition of ROCK by atorvastatin (80mg/d) remained significant even after controlling for changes in low-density lipoprotein cholesterol (LDL-C) and triglycerides (p=0.01). Furthermore, there was no correlation between changes in ROCK activity and changes in LDL-C (r=0.2, p=0.25) or triglycerides (r=0.1, p=0.55). There was a modest correlation between ROCK inhibition and change in hs-CRP among patients randomized to atorvastatin 80mg/d (r=0.6, p=0.07).
These first-in-man findings demonstrate that high-dose atorvastatin rapidly inhibits the pro-atherogenic Rho/ROCK pathway, independent of cholesterol reduction. This inhibition may contribute to the clinical benefits of statins. Rho/ROCK may provide a useful therapeutic target in patients with atherosclerosis.
- [show abstract] [hide abstract]
ABSTRACT: The mevalonate pathway produces isoprenoids that are vital for diverse cellular functions, ranging from cholesterol synthesis to growth control. Several mechanisms for feedback regulation of low-density-lipoprotein receptors and of two enzymes involved in mevalonate biosynthesis ensure the production of sufficient mevalonate for several end-products. Manipulation of this regulatory system could be useful in treating certain forms of cancer as well as heart disease.Nature 03/1990; 343(6257):425-30. · 38.60 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: We sought to determine whether Rho kinase (ROCK) activity is increased in a Taiwanese population with metabolic syndrome (MetS). Recent studies suggest that ROCK may be involved in the pathogenesis of MetS, but clinical studies linking ROCK with MetS are lacking. We studied 40 Taiwanese subjects (60% men, mean age 55.5 +/- 5.6 years) who were diagnosed with MetS with National Cholesterol Educational Program Adult Treatment Panel III criteria and 40 age- and gender-matched control subjects. Subject demographics were recorded, and blood samples were obtained. Compared with control subjects, ROCK activity, as determined by phosphorylation of myosin binding subunit (MBS) in leukocytes, was greater in MetS subjects (mean phospho-MBS/MBS ratio 0.46 vs. 0.35, p = 0.002). A cutoff value for ROCK activity of 0.39 predicted the presence of MetS with specificity and sensitivity rates of 70%. Plasma high-sensitivity C-reactive protein was greater (5.5 mg/l, 95% confidence interval [CI] 3.1 to 7.2 mg/l vs. 2.8 mg/l, 95% CI 1.1 to 3.9 mg/l, p = 0.01) and adiponectin was lower (4.9 microg/ml, 95% CI 3.2 to 6.1 microg/ml vs. 5.9 microg/ml, 95% CI 4.2 to 7.5 microg/ml, p = 0.01) in MetS subjects compared with control subjects, but plasma levels of interleukin-6 and tumor necrosis factor-alpha were not different (p > 0.05 for both). Body mass index, waist circumference, fasting glucose, high-sensitivity C-reactive protein, and triglyceride levels were associated with increased levels of ROCK activity. The risk of increased ROCK activity increased with the number of MetS components (p for trend <0.001). Rho kinase activity is increased in Taiwanese subjects with MetS and is associated with each component of MetS and markers of inflammation. These findings suggest that ROCK activity may be a novel serological marker of MetS.Journal of the American College of Cardiology 04/2007; 49(15):1619-24. · 14.09 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: To study whether vascular dysfunction in hypercholesterolaemia is reversible, we investigated patients without overt arterial disease who were taking maintenance treatment for hypercholesterolaemia. Medication was stopped for 2 weeks, reinstituted for 12 weeks, and again stopped for 6 weeks. During both maintenance treatment and the 12 weeks of step-up medication the lipid profile was improved but did not return to normal. Dose-response curves for serotonin-induced vasodilatation, an index of nitric oxide-dependent vasodilatation, showed a comparable and significant rightward shift after a medication-free period of 2 and 6 weeks compared with control subjects, indicating endothelial dysfunction, which was already maximum after 2 weeks. After 12 weeks of lipid-lowering medication, the difference in endothelial function between controls and patients had disappeared. Co-infusion of L-arginine, the substrate for nitric oxide synthase, returned the impaired serotonin response during hypercholesterolaemia to normal, but had no effect on this response in controls or in patients while on lipid-lowering medication. Neither endothelium-independent vasorelaxation, assessed by sodium nitroprusside infusion, nor vasoconstriction induced by the nitric oxide blocker L-NMMA, were different between controls and patients, whether the latter were on or off lipid-lowering medication. Our results show an L-arginine-sensitive, impaired nitric-oxide-mediated vascular relaxation of forearm resistance vessels in hypercholesterolaemia which is reproducible, and reversible after short-term lipid-lowering therapy. Demonstration of such changes in this readily accessible vascular bed will allow larger trials assessing vascular function during lipid-lowering therapy to be done.The Lancet 09/1995; 346(8973):467-71. · 39.06 Impact Factor
Atherosclerosis 205 (2009) 517–521
Contents lists available at ScienceDirect
journal homepage: www.elsevier.com/locate/atherosclerosis
Statins inhibit Rho kinase activity in patients with atherosclerosis
Anju Nohriaa, Adnan Prsica, Ping-Yen Liub, Ryuji Okamotoa, Mark A. Creagera, Andrew Selwyna,
James K. Liaoa, Peter Ganzc,∗
aCardiovascular Division, Brigham and Women’s Hospital, Boston, MA, USA
bCardiovascular Division, National Cheng Kung University Hospital/Cardiovascular Research Center,
National Cheng Kung University, Tainan, Taiwan
cCardiovascular Division, San Francisco General Hospital, 1001 Potrero Avenue, San Francisco, CA 94110, USA
a r t i c l ei n f o
Received 14 September 2008
Received in revised form 11 December 2008
Accepted 12 December 2008
Available online 24 December 2008
a b s t r a c t
Background: In addition to inhibiting cholesterol synthesis, statins (HMG-CoA reductase inhibitors)
decrease the formation of isoprenoid intermediates required for the activation of key signaling pathways,
including Rho/Rho kinase (ROCK). In experimental settings, statins inhibit ROCK and reverse vascular
dysfunctions in atherosclerosis, independent of cholesterol reduction. It is not known whether statins
inhibit ROCK activity in humans with atherosclerosis.
Methods: We investigated 35 patients with stable atherosclerosis in a randomized, double-blind study
comparing treatment with high-dose (80mg/d) or low-dose (10mg/d) atorvastatin to placebo for 28
days. Blood samples for leukocyte ROCK activity, fasting lipids, and high-sensitivity C-reactive protein
(hs-CRP) were obtained on days 0, 7, 14, and 28 after randomization and change over time with the two
statin treatments relative to placebo was examined.
Results: Atorvastatin 80mg/d reduced ROCK activity (p=0.002 vs. placebo). This decline was rapid and
significant within 2 weeks of treatment. The inhibition of ROCK by atorvastatin (80mg/d) remained sig-
(p=0.01). Furthermore, there was no correlation between changes in ROCK activity and changes in LDL-C
and change in hs-CRP among patients randomized to atorvastatin 80mg/d (r=0.6, p=0.07).
atherogenic Rho/ROCK pathway, independent of cholesterol reduction. This inhibition may contribute
to the clinical benefits of statins. Rho/ROCK may provide a useful therapeutic target in patients with
© 2008 Elsevier Ireland Ltd. All rights reserved.
3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reduc-
tase inhibitors (statins) are accepted first line agents for the
treatment of hyperlipidemia to reduce the risk of adverse car-
diovascular events. Statins lower serum cholesterol by inhibiting
HMG-CoA reductase, the rate-limiting enzyme in the mevalonate
pathway that is responsible for cholesterol synthesis . Meval-
such as farnesylpyrophosphate and geranylgeranylpyrophosphate
. These isoprenoid intermediates are important for membrane
translocation and activation of small guanosine triphosphate (GTP)
binding proteins, including Rho . Rho and its downstream effec-
∗Corresponding author. Tel.: +1 415 206 3024; fax: +1 415 206 8965.
E-mail address: email@example.com (P. Ganz).
tor, Rho kinase (ROCK), play an important role in regulating the
actin cytoskeleton and thereby affect intracellular transport, gene
transcription, and messenger RNA expression and stability . In
cultured cells and in animals, inhibition of Rho/ROCK by statins
exerts an anti-atherogenic effect that is independent of cholesterol
reduction. Yet in animals, the doses of statins reported to inhibit
Rho/ROCK in vivo are far higher (1–2 log units higher on a per kilo-
gram basis) than those employed in clinical practice , raising
doubt about the relevance of these findings to humans.
Development of an assay of ROCK activity [5,6] has permitted us
the Rho/ROCK pathway in subjects with atherosclerosis, (2) that
this inhibition occurs rapidly, (3) that it is particularly pronounced
with the intensive dosing of statins found to be advantageous in
recent clinical trials , and (4) that any inhibition of ROCK by
statins correlates with an anti-inflammatory effect (assessed by
high-sensitivity C-reactive protein).
0021-9150/$ – see front matter © 2008 Elsevier Ireland Ltd. All rights reserved.
A. Nohria et al. / Atherosclerosis 205 (2009) 517–521
2.1. Study subjects
The Human Research Committee at Brigham and Women’s
Hospital approved this study. We enrolled subjects with stable
atherosclerosis who met the modified NCEP ATP III guideline
criteria for initiation of statin therapy . A complete history,
physical examination, and laboratory evaluation was performed
for each subject. Atherosclerosis was defined by the presence of
≥50% stenosis in at least one coronary artery by cardiac catheter-
ization, prior myocardial infarction, prior revascularization, prior
thrombo-embolic stroke, or documented peripheral arterial dis-
ease. Exclusion criteria included an unstable coronary syndrome,
revascularization, or severe heart failure within 3 months of study
enrollment, malignancy, chronic inflammatory disease, chronic
infection, pregnancy, low-density lipoprotein cholesterol (LDL-C)
<2.6mmol/L (100mg/dL) off statin therapy, prior intolerance to
statins, liver transaminases >2 times normal, creatine phosphok-
inase >3 times normal, serum creatinine >3mg/dL, and reluctance
to discontinue statins for the duration of the study. Subjects were
throughout the study. All study blood samples were drawn after an
overnight fast, before subjects had taken their medications.
2.2. Study design
The study was a randomized, double-blind, placebo-controlled,
three parallel-arms trial. Subjects who signed informed consent
and met the inclusion/exclusion criteria were asked to discon-
tinue statins for a minimum of 2 weeks. This period is sufficient to
restore the lipid profile to pre-statin treatment levels . Subjects
were then randomized to receive 1 month of low-dose atorvas-
Blood for leukocyte ROCK activity, fasting lipids, high-sensitivity
C-reactive protein (hs-CRP), and safety assessment was collected
on days 0, 7, 14, and 28 of randomized treatment. Subjects were
instructed to resume their routine lipid-lowering therapy upon
We randomized a total of 45 subjects in this study. Four sub-
jects were withdrawn on day 0 for LDL-C <2.6mmol/L (100mg/dL),
one subject was withdrawn on day 0 for creatine phosphokinase
>3 times normal, one subject withdrew consent after day 0, and
three additional subjects were withdrawn for acute cholecystitis,
elevation in liver enzymes on study drug, and medication non-
compliance. A total of 36 subjects completed the study and all
except one subject with diabetes but no documented evidence of
atherosclerosis were included in the analysis. Only one subject had
missing data on day 7.
2.3. Measurement of Rho kinase activity
ROCK activity was assayed in peripheral blood leukocytes as
the proportion of phospho-Thr853in the myosin binding subunit
(MBS) of myosin light chain phosphatase . Blood was collected
at room temperature in heparinized tubes (20U/mL) containing
10mM fasudil (Asahi Chemical Industry Co. Ltd., Japan). Fasudil
was added to inhibit ROCK activity, and hence further formation
of phospho-Thr853-MBS ex vivo . In our experience, there is no
appreciable dephosphorylation of phospho-Thr853-MBS at room
described previously [5,6]. The leukocyte pellet was suspended in
achieve 5×106cells/mL. Fixative solution (50% trichloroacetic acid
(Sigma Chemical, IL), 50mmol/L dichlorodiphenyltrichloroethane
(Sigma Chemical, IL), and protease inhibitors (Calbiochem, EMD
tion and the resulting precipitate was stored at −80◦C for Western
Western blot analysis was performed as described previously
 using rabbit anti-phospho-specific Thr853-MBS polyclonal anti-
body (generous gift of Dr. Ikebe, Worcester, MA) or rabbit anti-MBS
polyclonal antibody (Covance Laboratories, IN). NIH 3T3 cell lysates
were used as a positive control. Rho kinase activity was expressed
as the ratio of phosphorylation levels of myosin binding subunit (p-
MBS) in each sample per p-MBS in each positive control divided by
MBS in each sample per MBS in each positive control .
2.4. Measurement of lipids and high-sensitivity C-reactive protein
Fasting serum lipids (total and high-density lipoprotein choles-
terol (HDL-C) and triglycerides) were measured with an Olympus
AU400 analyzer using enzymatic methods. LDL-C was calcu-
lated according to the methods of Friedewald et al. . Serum
hs-CRP was quantified by latex-enhanced nephelometry on the
BNTMnephelometry system (Dade Behring, Deerfield, IL).
Atorvastatin (10mg and 80mg) was obtained from Pfizer, Inc.
(Morris Plains, NJ). The different strengths of atorvastatin and
placebo tablets were encapsulated and matched to facilitate blind-
investigational drug pharmacy at Brigham and Women’s Hospital.
2.6. Statistical analysis
Descriptive and experimental measures are expressed as
mean±SD or median (25th percentile, 75th percentile) as appro-
priate. Baseline characteristics were compared between the three
treatment groups using one-way ANOVA or the Kruskal–Wallis
test for continuous variables and Fisher’s exact test for discrete
variables. Triglycerides and hs-CRP were not normally distributed
and were log transformed for the regression analyses. The effect
of treatment by randomization subgroup on the average change
in dependent variables (ROCK activity, lipids, and hs-CRP) from
baseline over time was assessed using a random effects regres-
sion model for longitudinal data (PROC MIXED). We fit a repeated
measures model with a random effect for subject and fixed effects
for treatment, time, and their interaction. We controlled for base-
line ROCK activity, lipids, and hs-CRP in the longitudinal models
to account for any baseline differences in these parameters that
may not have been statistically significant because of the mod-
est sample size. Correlation between change in ROCK activity and
change in LDL-C, triglycerides, and hs-CRP from baseline to each
time point was assessed using Pearson’s and Spearman’s correla-
tion coefficients, as appropriate. All analyses were conducted using
SAS software (version 9.1). All statistical tests were two-sided, with
an alpha level of 0.05.
3.1. Baseline characteristics
Subjects in all three treatment arms were well-matched for age,
gender, race, cardiac risk factors, and medications (Table 1).
3.2. Effect of statin therapy on Rho kinase activity
Baseline ROCK activity did not differ significantly between the
3 treatment groups (Table 1). Nonetheless, we controlled for base-
line ROCK activity in the longitudinal analyses due to differences
A. Nohria et al. / Atherosclerosis 205 (2009) 517–521
Characteristic Placebo (n=14) Atorvastatin 10mg (n=10) Atorvastatin 80mg (n=11)
Male, n (%)
Caucasian, n (%)
Hypertension, n (%)
Diabetes, n (%)
Smoker, n (%)
Aspirin, n (%)
Beta-blocker, n (%)
Statin, n (%)
HDL cholesterol (mmol/L)
LDL cholesterol (mmol/L)
High-sensitivity CRP (mg/L)
Rho kinase activity
2.5 [1.3, 3.0]
1.8 [1.0, 6.4]
2.4 [1.2, 2.8]
2.3 [0.9, 4.3]
1.5 [1.3, 2.9]
1.2 [0.5, 5.2]
There are no statistically significant differences between the treatment groups. Data are presented as mean±SD or median [25th, 75th percentile].
that may have been present but were not statistically apparent due
to the modest sample size. ROCK activity did not change over time
in subjects randomized to placebo (p=0.29 vs. baseline) and only
trended to decline with atorvastatin 10mg/d (p=0.10 vs. placebo)
(Fig. 1). Atorvastatin 80mg/d decreased ROCK activity over time
(p=0.02) and this reduction was highly significant compared to
placebo (p=0.002) (Fig. 1). The time course of ROCK inhibition by
high-dose atorvastatin (Fig. 1) revealed a rapid reduction in ROCK
activity, becoming statistically significant within 14 days of treat-
ment (change from baseline relative to placebo at day 7, p=0.06;
day 14, p=0.04; and day 28, p=0.003). Representative Western
blots depicting the change in ROCK activity over time are shown in
3.3. Effect of statin therapy on lipids
Subjects in all three treatment groups had similar lipid profiles
eter during the study period in subjects randomized to placebo
(see Supplementary data). The stable lipid concentrations in the
placebo arm indicate that the 2-week statin washout was sufficient
to re-establish baseline levels. As expected, both doses of ator-
vastatin reduced total cholesterol and LDL-C compared to placebo
(p<0.0001), with the high-dose (80mg/d) being more effective
atorvastatin, reduced triglycerides relative to placebo (p=0.0002).
Neither dose of atorvastatin changed HDL-C compared to
Fig. 1. Effect of statins on Rho kinase activity. Results are expressed as mean±SE.
binding subunit of myosin light chain phosphatase (pThr853-MBS) relative to stain-
ing of total myosin binding subunit of myosin light chain phosphatase (MBS). All
comparisons control for baseline ROCK activity.
3.4. Effect of statin therapy on high-sensitivity C-reactive protein
High-sensitivity CRP levels were similar at baseline in all
three treatment groups (Table 1). Hs-CRP levels did not change
significantly from baseline within any treatment group (see
Supplementary data). However, the trend over time in subjects
treated with atorvastatin 80mg/d showed a significant decline in
hs-CRP compared to those treated with placebo (p=0.02) or ator-
vastatin 10mg/d (p=0.04).
3.5. Lipid levels and Rho kinase activity
To test the hypothesis that ROCK inhibition by atorvastatin is
independent of lipid-lowering, we controlled for changes in both
LDL-C and triglycerides in the longitudinal model. The effect of
treatment on ROCK activity remained significant after controlling
for change in LDL-C (atorvastatin 80mg/d vs. placebo, p=0.004),
change in triglycerides (atorvastatin 80mg/d vs. placebo, p=0.02),
and reductions in both LDL-C and triglycerides simultaneously
(atorvastatin 80mg/d vs. placebo, p=0.01). Furthermore, there was
no correlation between change in ROCK activity and change in LDL-
C or change in triglycerides at any time point during the study or
with either statin dose (Fig. 3).
3.6. Rho kinase activity and high-sensitivity C-reactive protein
To examine whether ROCK inhibition contributes to the anti-
inflammatory effects of statin therapy, we correlated the change
in ROCK activity with change in hs-CRP levels at each time point
in the study. For the study population as a whole, there was no
correlation between ROCK inhibition and change in hs-CRP at any
time point during the study. However, among those randomized
to atorvastatin 80mg/d, there was a modest correlation between
ROCK inhibition and reduction in hs-CRP after 1 month of ther-
Fig. 2. Western blot analyses of Rho kinase activity. Shown are representa-
tive blots of ROCK activity (p-MBS/t-MBS) over time in patients randomized to
placebo, atorvastatin 10mg/d, and atorvastatin 80mg/d, respectively. D=day, p-
MBS=phosphorylated MBS, and t-MBS=total MBS.
A. Nohria et al. / Atherosclerosis 205 (2009) 517–521
Fig. 3. Correlation of reduction in Rho kinase activity with reduction in lipid param-
eters. For the entire cohort of 35 patients, there was no correlation between change
in ROCK activity and change in LDL cholesterol (Panel A) or change in triglycerides
(Panel B) at any time point during the study. The scatter-plot depicts the correlation
in the change from day 28 to baseline for all parameters.
Fig. 4. Correlation of change in Rho kinase activity with change in hs-CRP. For the
B). The scatter-plot depicts the correlation in the change from day 28 to baseline.
apy (r=0.6, p=0.07) (Fig. 4). Furthermore, there was no correlation
between change in LDL-C and hs-CRP levels throughout the study.
statins inhibit the pro-atherogenic Rho/ROCK pathway in vivo, in a
dose- and time-dependent manner. While both low (10mg/d) and
intensive (80mg/d) dose atorvastatin lowered serum cholesterol,
only the intensive dose achieved significant ROCK inhibition rel-
ative to placebo. This inhibition was significant within 2 weeks of
icant even after controlling for changes in LDL-C and triglycerides.
Inhibition of ROCK in patients on atorvastatin 80mg/d correlated
modestly with a reduction in C-reactive protein. Accordingly, these
data demonstrate that clinically approved doses of statins, and in
particular intensive doses, inhibit ROCK activity in humans with
anism elucidated in animal studies, may provide the mechanistic
underpinning for the rapid clinical benefits of statin therapy that
are independent of lipid-lowering and potentially related to an
anti-inflammatory effect manifest by a reduction in hs-CRP.
4.1. Lipid-independent actions of statins
Evidence for the lipid-independent “pleiotropic” effects of
statins derives partly from statistical analyses of clinical tri-
als demonstrating that improved outcomes correlate as much
with anti-inflammatory actions of statins as with LDL-C low-
ering [11–13]. Furthermore, when similar reductions in LDL-C
are achieved, only statins but not ezetimibe, a drug that lowers
LDL-C without inhibiting HMG-CoA reductase, reverse endothelial
dysfunction , reduce platelet reactivity , and inhibit pro-
inflammatory cytokines .
4.2. Rho/Rho kinase pathway
In experimental studies, inhibition of Rho/ROCK has been impli-
cated as a potential mechanism for many of the lipid-independent
“pleiotropic” benefits of statins. By reducing mevalonate synthesis,
statins prevent the formation of isoprenoid intermediates required
for the membrane translocation and GTP binding activity of small
GTPases such as Rho, Ras, and Rac . Direct inhibition of Rho or
ROCK is anti-atherogenic by augmenting endothelial nitric oxide
synthesis , decreasing vascular smooth muscle cell contrac-
tion and proliferation , decreasing cytokine formation and
thrombogenicity of the vessel wall . Statins replicate these vas-
inhibit Rho/ROCK are far higher than those used by clinicians rais-
ing legitimate concerns about the relevance of these experimental
findings to practice . The development of a quantitative assay of
ROCK activity in our laboratory has facilitated investigations of this
pathway in humans [5,6].
4.3. Consequences of Rho kinase inhibition by statins in humans
In this study, atorvastatin 80mg/d inhibited ROCK activity by
approximately 49% compared to placebo. What might be the con-
sequences of this magnitude of ROCK inhibition? Previously, we
fasudil, and have observed improved brachial artery endothelial
function associated with 59% inhibition of ROCK activity . This
degree of ROCK inhibition was similar to that achieved in the
present study with atorvastatin 80mg/d. In the present study,
we found a modest correlation between ROCK inhibition and an
anti-inflammatory effect measured as reduction in hs-CRP (r=0.6,
esis that Rho/ROCK inhibition mediates the anti-inflammatory
effects of statins and potentially explains the clinical benefit
observed in the JUPITER study in patients with elevated CRP levels
treated with intensive statin therapy .
Due to the complexity of isolating leukocytes to measure ROCK
activity at several time points per patient, this study is of necessity
modest in size. Therefore, it is possible that we were inadequately
powered to detect a significant difference in ROCK inhibition
between low-dose atorvastatin and placebo.
A. Nohria et al. / Atherosclerosis 205 (2009) 517–521
ficult to separate. Previous studies have shown that oxidized LDL
and triglycerides promote ROCK activity [6,24]. Thus, it is likely
high-dose atorvastatin inhibited ROCK activity even when control-
ling for reductions in LDL-C and triglycerides. Future studies will
that does not inhibit HMG-CoA reductase, inhibits ROCK.
We have assessed ROCK activity in leukocytes as these cells are
readily accessible with a blood draw. It is possible that circulat-
ing leukocytes do not accurately represent ROCK activity within
the vessel wall. Yet, leukocytes are very relevant to studies of
atherosclerosis . Trafficking of leukocytes to sites of atheroscle-
rosis is controlled by their ROCK activity [18,26,27]. Atherosclerosis
is reduced in hypercholesterolemic mice whose bone marrows
have been replaced with bone marrows from genetically deficient
ROCK−/−mice . Deficiency of ROCK is associated with impaired
chemotaxis and trafficking of monocyte derived macrophages to
sites of injury and atherosclerosis [26,27].
Lastly, this paper did not assess the effect of statins on other
members of the Ras superfamily of small GTPases, including Ras,
Rac, and Cdc-42, that may also play a role in mediating the vascular
yses will assess the effect of statins on these GTPases as techniques
to assess their downstream effects in humans become available.
In conclusion, this is the first study to demonstrate that in
humans with atherosclerosis intensive treatment with statins
rapidly inhibits ROCK activity, at least in part, independent of
cholesterol reduction. The Rho/ROCK signal transduction pathway
rosis and normal lipid levels. The clinical relevance of Rho/ROCK
inhibition by statins or direct ROCK inhibitors deserves further
Sources of funding: This work was supported by grants from the
National Institutes of Health (HL052233 to J.K. Liao; PO1 HL-48743
Inc. (Morristown, NJ). P.Y. Liu is a recipient of a National Health
Research Institute grant from Taiwan. Dr. M.A. Creager is the Simon
C. Fireman scholar in Cardiovascular Medicine.
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