Effect of cilostazol on impaired vasodilatory response of the brachial artery to ischemia in smokers

Can Serum Endocan Levels be Used as an Early Prognostic Marker for Endothelial Dysfunction in COVID-19?

In this study, we aimed to investigate whether degree of pneumonia and COVID-19 prognosis are associated with serum endocan levels at the early stage, when vascular damage has started. Patients between the ages of 18-85 years who were hospitalized and followed up with a diagnosis of COVID-19 were included in the study. A total of 80 patients were divided into 2 groups as mild/moderate pneumonia and severe pneumonia. Serum endocan levels were measured on the 8th day from the onset of symptoms in all patients. Of the 80 patients included in the study, 56.3% were female and 43.8% were male. There was no significant relationship between serum endocan levels and degree of pneumonia (P = .220) and prognosis of the disease (P = .761). The correlation analysis indicated a weak positive correlation between serum endocan levels and lactate level in venous blood gas (r = .270; P = .037). During the 28-day follow-up, the mortality rate was 3.75%. It was determined that the serum endocan levels was not associated with the degree of pneumonia and was not an early prognostic marker for COVID-19.

Ameliorative role of rolipram, PDE-4 inhibitor, against sodium arsenite-induced vascular dementia in rats

Arsenic exposure to the population leads to serious health problems like neurotoxicity, nephrotoxicity, and cardiovascular abnormality. In the present study, the work has been commenced to discover the prospect of rolipram a phosphodiestrase-4 (PDE-4) inhibitor against sodium arsenite (SA)-induced vascular endothelial dysfunction (EnDF) leading to dementia in rats. Wistar rats were treated with SA (5 mg/kg body weight/day orally) for 44 days for induction of vascular EnDF and dementia. Learning and memory were evaluated using Morris water maze (MWM) test. Vascular EnDF was evaluated using aortic ring preparation. Various biochemical parameters were also evaluated like brain oxidative stress (viz. reduced glutathione and thiobarbituric acid reactive substances level), serum nitrite/nitrate activity, acetylcholinesterase activity, and inflammatory markers (viz. neutrophil infiltration in brain and myeloperoxidase). SA-treated rats showed poor performance in water maze trials indicating attenuated memory and ability to learn with significant rise (p < 0.05) in brain acetylcholinesterase activity, brain oxidative stress, neutrophil count, and significant decrease (p < 0.05) in serum nitrite/nitrate levels and vascular endothelial functions. Rolipram (PDE-4 inhibitor) treatment (0.03 mg/kg and 0.06 mg/kg body weight, intraperitoneally daily for 14 days) significantly improved memory and learning abilities, and restored various biochemical parameters and EnDF. It is concluded that PDE-4 modulator may be considered the prospective target for the treatment of SA-induced vascular EnDF and related dementia.

Update on Cilostazol: A Critical Review of Its Antithrombotic and Cardiovascular Actions and Its Clinical Applications

Cilostazol, a phosphodiesterase III inhibitor, has vasodilating and antiplatelet properties with a low rate of bleeding complications. It has been used over the past 25 years for improving intermittent claudication in patients with peripheral artery disease (PAD). Cilostazol also has demonstrated efficacy in patients undergoing percutaneous revascularization procedures for both PAD and coronary artery disease. In addition to its antithrombotic and vasodilating actions, cilostazol also inhibits vascular smooth muscle cell proliferation via phosphodiesterase III inhibition, thus mitigating restenosis. Accumulated evidence has shown that cilostazol, due to its "pleiotropic" effects, is a useful, albeit underutilized, agent for both coronary artery disease and PAD. It is also potentially useful after ischemic stroke and is an alternative in those who are allergic or intolerant to classical antithrombotic agents (eg, aspirin or clopidogrel). These issues are herein reviewed together with the pharmacology and pharmacodynamics of cilostazol. Large studies and meta-analyses are presented and evaluated. Current guidelines are also discussed, and the spectrum of cilostazol's actions and therapeutic applications are illustrated.

Endothelium as a Therapeutic Target in Diabetes Mellitus: From Basic Mechanisms to Clinical Practice

Endothelium plays an essential role in human homeostasis by regulating arterial blood pressure, distributing nutrients and hormones as well as providing a smooth surface that modulates coagulation, fibrinolysis and inflammation. Endothelial dysfunction is present in Diabetes Mellitus (DM) and contributes to the development and progression of macrovascular disease, while it is also associated with most of the microvascular complications such as diabetic retinopathy, nephropathy and neuropathy. Hyperglycemia, insulin resistance, hyperinsulinemia and dyslipidemia are the main factors involved in the pathogenesis of endothelial dysfunction. Regarding antidiabetic medication, metformin, gliclazide, pioglitazone, exenatide and dapagliflozin exert a beneficial effect on Endothelial Function (EF); glimepiride and glibenclamide, dipeptidyl peptidase-4 inhibitors and liraglutide have a neutral effect, while studies examining the effect of insulin analogues, empagliflozin and canagliflozin on EF are limited. In terms of lipid-lowering medication, statins improve EF in subjects with DM, while data from short-term trials suggest that fenofibrate improves EF; ezetimibe also improves EF but further studies are required in people with DM. The effect of acetylsalicylic acid on EF is dose-dependent and lower doses improve EF while higher ones do not. Clopidogrel improves EF, but more studies in subjects with DM are required. Furthermore, angiotensin- converting-enzyme inhibitors /angiotensin II receptor blockers improve EF. Phosphodiesterase type 5 inhibitors improve EF locally in the corpus cavernosum. Finally, cilostazol exerts favorable effect on EF, nevertheless, more data in people with DM are required.

Impaired Brachial Flow-Mediated Dilatation May Predict Symptomatic Intracranial Arterial Dissections

BACKGROUND AND PURPOSE

Spontaneous intracranial arterial dissections are characterized by the sudden disruption of the internal elastic lamina in the intracranial arteries. The purpose of our retrospective study was to investigate whether patients with nontraumatic intracranial arterial dissections had normal endothelial function.

METHODS

The study included symptomatic patients with nontraumatic intracranial arterial dissections who underwent an endothelial function test. Controls were selected from headache patients matched for sex and age. Endothelial function was assessed using flow-mediated dilatation. We investigated patients' ankle brachial index and pulse wave velocity to determine the degree of atherosclerosis. Patient characteristics, brachial flow-mediated dilatation, ankle brachial index, and pulse wave velocity were compared between the 2 groups.

RESULTS

During the study period, there were 22 patients with nontraumatic intracranial arterial dissections matched with 22 controls. Clinical characteristics were compared between the groups. Although there were no significant differences in ankle brachial index or pulse wave velocity between the 2 groups, patients with intracranial arterial dissections had lower flow-mediated dilatation values than controls (median flow-mediated dilatation, 3.95% in dissection patients versus 7.3% in controls, P = .0035). Brachial flow-mediated dilatation was impaired in symptomatic patients with nontraumatic intracranial arterial dissections despite the normal ankle brachial index and pulse wave velocity.

CONCLUSIONS

Impaired brachial flow-mediated dilatation is a probable predictor of intracranial arterial dissections.

Alpha-2-macroglobulin as a Promising Biological Marker of Endothelial Function

Aims: Alpha-2-macroglobulin (α₂MG) is thought to be associated with inflammatory reactions and procoagulant properties that might cause ischemic stroke. Endothelial dysfunction plays an important role in atherosclerosis development and in the occurrence of cardiovascular events. In this study, we investigated whether serum α₂MG levels, endothelial function, and endothelial progenitor cell (EPC) number were associated in patients with chronic stroke or cardiovascular risk factors.

Methods: Patients with a history of stroke or any established cardiovascular risk factors were enrolled in this study (n = 102; 69 men, 70.1 ± 9.2 years). Endothelial function was assessed by flow-mediated dilation (FMD). EPC numbers (CD34+/CD133+) were measured using flow cytometry (n = 91). Serum α₂MG levels were measured by nephelometry.

Results: Patients in the highest tertile of serum α₂MG levels were older (P = 0.019) and more frequently exhibited dyslipidemia (P = 0.021). Univariate-regression analysis revealed that increased α₂MG levels were negatively associated with FMD values (r = −0.25; P = 0.010), whereas increased EPC numbers were positively associated (r = 0.21; P = 0.044). Multivariate-regression analysis adjusted for male gender, hypertension, and severe white-matter lesions showed that serum α₂MG levels were independently associated with FMD values (standardized partial regression coefficient [β] −0.185; P = 0.033), although not significantly associated with EPC numbers.

Conclusion: Serum α₂MG levels might reflect endothelial dysfunction evaluated by FMD in patients with chronic stroke or cardiovascular risk factors.

Cilostazol improves endothelial function in acute cerebral ischemia patients: a double-blind placebo controlled trial with flow-mediated dilation technique

Background

In order to evaluate the impact of cilostazol on endothelial function, we compared the changes of flow-mediated dilation (FMD) between aspirin and cilostazol groups in patients with acute cerebral ischemia.

Methods

Patients presenting with acute cerebral ischemic events were randomly assigned into aspirin (n = 40) or cilostazol (n = 40) group in a double-blinded manner. FMD was measured at baseline (T0) and 90 days (T1). We measured L-arginine at baseline (a precursor of biologically active nitric oxides). Serious and non-serious adverse events were described.

Results

Despite no difference in the baseline FMD values (p = 0.363), there was a significant increase of FMD values in cilostazol group (7.9 ± 2.4 to 8.9 ± 2.3%, p = 0.001) and not in aspirin group (8.5 ± 2.6 to 9.3 ± 2.8%, p = 0.108). In the multiple regression analysis performed in cilostazol group, serum L–arginine levels were inversely correlated with FMD at T1 (ß = −0.050, SE: 0.012, p < 0.001) with age, total cholesterol levels, and C-reactive protein as confounders. While T0 FMD values in both aspirin and cilostazol groups did not show any correlation with serum L-arginine levels, the correlation is restored in the cilostazol group at T1 (r = 0.467, p = 0.007), while such is not shown in the aspirin group. There was no difference of serious adverse events between the two groups (p = 0.235). Adverse events were more common in the cilostazol group (35/40 vs. 25/40, p = 0.010), due to frequent headaches (14/40 vs. 3/30, p = 0.003) which was well tolerated.

Conclusion

Cilostazol improved endothelial function in acute cerebral ischemia patients. It also restored an inverse correlation between 3-month FMD and baseline L-arginine levels.

Trial registration

NCT03116269, 04/12/2017, retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12883-017-0950-y) contains supplementary material, which is available to authorized users.

The Effect of Cilostazol on Endothelial Function as Assessed by Flow-Mediated Dilation in Patients with Coronary Artery Disease

Aim: The vascular endothelium plays a key role in the pathophysiology of atherosclerosis. Flow-mediated dilation (FMD) is a novel way of assessing endothelial function. Cilostazol is a unique antiplatelet drug that also has the potential to improve endothelial function. The objective of this present study was to investigate the effects of cilosatzol on endothelial function as assessed by FMD.

Methods: Fifty-one patients with coronary artery disease (CAD) were assigned to one of two groups: the Cilostazol(+) group (with cilostazol) and Cilostazol(−) group (without cilostazol). In addition to conventional dual antiplatelet therapy with aspirin and clopidogrel/ticlopidine, the Cilostazol(+) group (n = 27) was also given cilostazol (100 mg/day). The Cilostazol(−) group (n = 24) did not receive cilostazol. FMD was assessed at enrollment and after 6–9 months.

Results: The FMD of both the Cilostazol(+) and Cilostazol(−) groups remained similar at 5.2 (interquartile range: 3.8–8.5) to 5.4 (interquartile range: 4.2–6.7) (P = 0.29) and 5.0 (interquartile range: 3.6–6.4) to 4.9 (interquartile range: 4.0–7.0) (P = 0.38), respectively. However, the diameters of the baseline and maximal brachial arteries tended to increase in the Cilostazol(−) group (baseline: 4.2 ± 0.7 to 4.4 ± 0.7, P = 0.18; maximal: 4.5 ± 0.7 to 4.6 ± 0.7 P = 0.22), whereas that of the Cilostazol(−) group tended to decrease (baseline: 4.1 ± 0.6 to 3.9 ± 0.5, P = 0.10; maximal: 4.3 ± 0.7 to 4.1 ± 0.5, P = 0.05). The rates of change in the baseline diameter (Cilostazol(+): 3.7 ± 9.8% vs. Cilostazol(−): −3.8 ± 12.2%, P = 0.03) and maximal diameter (Cilostazol(+): +3.1 ± 8.9% vs. Cilostazol(−): −4.4 ± 12.0%, P = 0.02) were significantly different.

Conclusion: Although cilostazol didn't affect the FMD, there was a significant difference in the rates of change in baseline and maximal brachial artery diameter. This may have a beneficial effect in patients with cardiovascular disease.

Optimal blood pressure in patients with peripheral artery disease following endovascular therapy

This study examined the associations between blood pressure (BP) and event incidence to define optimal BP after endovascular therapy (EVT) in patients who underwent EVT. BP was monitored every 6 months for 5 years, and the patients were divided into two groups by average BP: ≥ 140/90 mmHg and < 140/90 mmHg. The association of BP with several events was examined. Although no significant differences in total mortality were observed between the groups, restenosis rates were significantly higher among patients who did not achieve target BP (36.2%) than among those who did (18.2%) (p < 0.01). The percentage of patients with glycosylated haemoglobin > 7.0% was significantly higher among those who did not achieve target BP in the restenosis group (42.9%) than in the other group (10.8%) (p < 0.01). In the restenosis group, there was a significantly higher percentage of patients taking metformin (p < 0.01) than in the other group. Metformin seemed to be administered to patients with more severe diabetes mellitus. In conclusion, it is important to manage hypertension and diabetes to prevent restenosis after EVT.

Cilostazol eliminates adverse smoking outcome in patients with drug-eluting stent implantation

BACKGROUND

The present study investigated whether cilostazol can eliminate adverse smoking outcome after percutaneous coronary intervention (PCI).

METHODS AND RESULTS

A total of 914 patients with successful drug-eluting stent (DES) implantation were randomly assigned to dual antiplatelet therapy (DAT; aspirin and clopidogrel, n=457) or to triple antiplatelet therapy (TAT; DAT with cilostazol, n=457). The effect of smoking on 2-year major adverse cardio/cerebrovascular events (MACCE) in both the TAT and DAT groups was evaluated. Total MACCE were not significantly different between the 2 anti-platelet regimens (9.8% in TAT vs. 11.4% in DAT groups, P=0.45), but the adverse effects of smoking on clinical outcome were different between DAT vs. TAT. Current smokers had a higher prevalence of MACCE than non-smokers in the DAT group (16.7% vs. 9.5%, P=0.04). In the TAT group, however, the adverse effect of smoking was abolished (9.2% vs. 10.1%, P=0.85). Regarding the effects of smoking on the antiplatelet effects of DAT or TAT, post-treatment platelet reactivity (in P2Y12 reaction units; PRU) in current smokers was not significantly lower than that in non-smokers in the DAT group, whereas, in the TAT group, it was significantly lower than that of non-smokers (189±88 vs. 216±89 PRU, P=0.01).

CONCLUSIONS

Adverse clinical effects of smoking may be eliminated by the addition of cilostazol to DAT after DES implantation. This may be due to the stimulation of cilostazol's antiplatelet effects by smoking.

Combined therapeutic effect of probucol and cilostazol on endothelial function in patients with silent cerebral lacunar infarcts and hypercholesterolemia: a preliminary study

OBJECTIVE

This study evaluated the efficacy of combined therapy with probucol and cilostazol on endothelial function in silent lacunar cerebral infarcts (SLCI) and mild hypercholesterolemia.

SUBJECTS AND METHODS

Flow-mediated vasodilatation (FMD) and nitroglycerin-induced vasodilatation (NMD) were measured before and after 4 weeks of combined therapy with probucol (500 mg/day) and cilostazol (200 mg/day) in 34 patients with a mean age of 72 ± 7 years (range 57-80 years) with SLCI, mild hypercholesterolemia (low-density lipoprotein cholesterol >100 mg/dl) and impaired endothelial function (FMD <6%). Patients were randomly allocated to one of the following two treatment groups: (1) aspirin (100 mg/day) with behavioral modifications, such as diet and/or exercise therapy (A group or control group, n = 17), and (2) probucol and cilostazol treatment (PC group, n = 17), also with behavioral modifications.

RESULTS

Although the baseline FMD was not different between the two treatment arms (2.7 ± 1.5 vs. 2.6 ± 1.5%, n.s.), the posttreatment FMD was significantly improved in the PC group (from 2.7 ± 1.5 to 3.5 ± 1.7%, p < 0.05) but not in the A group (from 2.6 ± 1.5 to 2.9 ± 1.4%, n.s.). No differences were observed between baseline and posttreatment NMD in either group. The effects of treatments on lipid profiles were more profound in the PC group.

CONCLUSION

Combined treatment with probucol and cilostazol resulted in subacute improvement in FMD/endothelial function in patients with SLCI with mild hypercholesterolemia. This combination therapy has the potential to reduce the risk of cardiovascular events via improvements in endothelial function and lipid profiles.

Evaluation of digital thermal monitoring as a tool to assess perioperative vascular reactivity

AIM

The inflammatory response following tissue injury after major surgery is known to affect endothelial function and vascular reactivity. In this study we evaluated the utility of bedside Digital Thermal Monitoring (DTM) as a surrogate for evaluating vascular function in the postoperative period.

METHODS

Ischemia-induced reactive hyperemia variables were measured in sixty patients scheduled for major thoracic surgery using DTM (VENDYS 5000BC; Endothelix, Inc., Houston, TX, USA) at baseline and at 24, 48, 72 hours, and day 5 postoperatively. Furthermore, baseline DTM variables (TR, aTR and AUCTR) and postoperative kinetics of these variables were compared among patients with and without preoperative chemo-radiation and cardiovascular risk factors.

RESULTS

There were no significant differences in the DTM parameters measured at baseline and on each of the studied postoperative days. Compared to the baseline, the lowest measures of all variables were observed 24 hrs postoperatively and the highest measures of all variables were observed at 72 hrs. Patients with abdominal obesity and smoking had lower DTM values than the rest of the study group.

CONCLUSIONS

In our study, DTM as measured by the VENDYS 5000BC DTM system (Endothelix, Inc.) did not reveal significant changes in ischemia-induced reactive hyperemia (vascular reactivity) between the baseline and after surgery in the postoperative period. Patients with certain cardiovascular risk factors (abdominal obesity, smoking) had a significant lower DTM signal. Whether this novel non-invasive technique is able to serve as a perioperative diagnostic tool for patients in a clinical setting warrants further study.

Restenosis after stent implantation for superficial femoral artery disease in patients treated with cilostazol

BACKGROUND

Restenosis after endovascular treatment for superficial femoral artery (SFA) disease remains a significant clinical issue. We assessed whether cilostazol reduce restenosis after SFA stenting with self-expandable nitinol stent.

METHODS

The study was a multicenter, prospective maintained database, retrospective analysis. From April 2004 to December 2009, 861 consecutive patients (mean age 71 years, 71% male) who underwent successful stenting for de novo lesions were retrospectively identified. Of them, 492 received cilostazol (cilostazol(+)) and 369 did not receive cilostazol (cilostazol(-)) after procedure. Propensity-score analyses matched 281 cilostazol(+) with 281 cilostazol (-) group. Primary endpoint was binary restenosis rate. Secondary endpoints were reocclusion, all-cause mortality and limb salvage in patients with critical limb ischemia (CLI). Restenosis was defined as >2.4 of peak systolic velocity ratio by duplex.

RESULTS

Mean follow-up period was 25 months. According to analysis of matched pairs, binary restenosis rates were significantly lower (31.2% vs. 42.9% at 5-year, P = 0.02). In-stent re-occlusion rate tended to be lower in patients who received cilostazol (10.8% vs. 18.2% at 5-year, P = 0.09) compared with control. No significant difference of all-cause mortality (21.4% vs. 18.3% at 5-year, P = 0.84) and limb salvage rate in patients with CLI (86.2% vs. 78.5% at 5-year, P = 0.29) was found between both groups. After adjustment for prespecified risk factors, cilostazol was an independent negative predictor of restenosis. In subgroup analysis, male, age <75 years, claudicant patients, TASCII C/D, small vessels and poor runoff vessel was significantly lower in binary restenosis.

CONCLUSIONS

Cilostazol reduced restenosis after SFA stenting with self-expandable nitinol stent and it seems to be more effective in high-risk patients for restenosis.

Endothelial dysfunction in the smokers can be improved with oral cilostazol treatment

BACKGROUND

Smoking is one of well known environmental factors causing endothelial dysfunction and plays important role in the atherosclerosis. We investigated the effect of cilostazol could improve the endothelial dysfunction in smokers with the measurement of flow-mediated dilatation (FMD).

METHODS

We enrolled 10 normal healthy male persons and 20 male smokers without any known cardiovascular diseases. After measurement of baseline FMD, the participants were medicated with oral cilostazol 100 mg bid for two weeks. We checked the follow up FMD after two weeks and compared these values between two groups.

RESULTS

There was no statistical difference of baseline characteristics including age, body mass index, serum cholesterol profiles, serum glucose and high sensitive C-reactive protein between two groups. However, the control group showed significantly higher baseline endothelium-dependent dilatation (EDD) after reactive hyperemia (12.0 ± 4.5% in the control group vs. 8.0 ± 2.1% in the smoker group, p = 0.001). However, endothelium-independent dilatation (EID) after sublingual administration of nitroglycerin was similar between the two groups (13.6 ± 4.5% in the control group vs. 11.9 ± 4.9% in the smoker group, p = 0.681). Two of the smoker group were dropped out due to severe headache. After two weeks of cilostazol therapy, follow-up EDD were significantly increased in two groups (12.0 ± 4.5% to 16.1 ± 3.7%, p = 0.034 in the control group and 8.0 ± 2.1% to 12.2 ± 5.1%, p = 0.003 in the smoker group, respectively). However, follow up EID value was not significantly increased compared with baseline value in both groups (13.6 ± 4.5% to 16.1 ± 3.7%, p = 0.182 in the control group and 11.9 ± 4.9% to 13.7 ± 4.3%, p = 0.430 in the smoker group, respectively).

CONCLUSION

Oral cilostazol treatment significantly increased the vasodilatory response to reactive hyperemia in two groups. It can be used to improve endothelial function in the patients with endothelial dysfunction caused by cigarette smoking.

Cilostazol inhibits cytokine-induced tetrahydrobiopterin biosynthesis in human umbilical vein endothelial cells

AIMS

Cilostazol, a type III phosphodiesterase inhibitor, is utilized for the treatment of intermittent claudication and is considered to have the beneficial effects against the atherogenic process. In the present study, we examined the effects of cilostazol on BH(4) biosynthesis in HUVEC treated with a mixture of the pro-inflammatory cytokines IFN-γ and TNF-α.

METHODS

Isolated HUVECs were grown to confluence and treated with IFN-γ (300 units/mL) and TNF-α (300 units/mL) for 16 h in order to stimulate BH(4) biosynthesis. The BH(4) levels were measured by HPLC. The mRNA expression of GTP cyclohydrolase I (GTPCH), the rate-limiting enzyme of BH(4) biosynthesis, and GTPCH feedback regulatory protein (GFRP) were quantified by real-time PCR. The GTPCH protein expression was assessed by western blot analysis.

RESULTS

Cilostazol significantly reduced the BH(4) levels in cytokine-stimulated HUVEC. Cilostazol produced a concomitant increase in the cAMP levels in HUVEC. Cilostazol decreased the GTPCH activity as well as the expression of GTPCH mRNA and protein. 8-bromo-cAMP (8Br-cAMP), a cell-permeable cAMP analogue, did not reproduce the effects of cilostazol. Cilostazol did not affect the cytokine-induced inhibition of GFRP mRNA expression.

CONCLUSIONS

We conclude that cilostazol inhibited cytokine-stimulated BH(4) biosynthesis via a cAMP-independent mechanism in HUVEC. Our data indicate that cilostazol reduced GTPCH activity and did so by suppressing the GTPCH protein levels.

A pooled analysis of the durability and predictors of treatment response of cilostazol in patients with intermittent claudication

Pharmacologic therapy for intermittent claudication in patients with peripheral artery disease (PAD) is limited. We aimed to determine the durability of cilostazol treatment response over time, treatment effects in various subpopulations, and long-term safety. This analysis pooled original data from nine randomized, controlled trials evaluating cilostazol in intermittent claudication, including 1258 subjects treated with cilostazol 100 mg bid. Analysis of covariance was used to compare differences in walking distance, and a pooled random-effects weighted mean difference in maximal walking distance (MWD) was determined. Temporal effects were analyzed by compiling data at 4-week intervals in studies of 24 weeks in duration. Cilostazol was associated with a 50.7% improvement from baseline in MWD compared with placebo (24.3%), with an absolute improvement of 42.1 meters greater than the improvement with placebo (p < 0.001) over a mean follow-up period of 20.4 weeks. Continued increases were demonstrated over the 24-week treatment period. These benefits were seen in all subgroups, after stratifying by age, sex, smoking status, duration of PAD, diabetes, hypertension, prior myocardial infarction, or beta-blocker use. Cilostazol did not increase the risk of all-cause mortality (RR 0.95 [0.68-1.35]). In conclusion, treatment with cilostazol achieves benefits in walking distance that are sustained at 24 weeks and observed irrespective of baseline clinical characteristics. Cilostazol demonstrated no increased risk of all-cause mortality.

Anti-inflammatory role of cilostazol in vascular smooth muscle cells in vitro and in vivo

AIM

Cilostazol is a selective inhibitor of phosphodiesterase 3, by which it increases intracellular cAMP and activates protein kinase A, thereby inhibiting platelet aggregation and inducing peripheral vasodilation. We investigated whether cilostazol might prevent nuclear factor (NF)-kappaB activation by activating AMP-activated protein kinase (AMPK) in vascular smooth muscle cells (VSMC).

METHODS AND RESULTS

Cilostazol was observed to activate AMPK, as well as its downstream target, acetyl-CoA carboxylase, in rat VSMC. Phosphorylation of AMPK with cilostazol was not affected by co-treatment with an adenylate cyclase inhibitor, SQ 22536. Furthermore, a cell-permeable cyclic AMP analog, pCTP-cAMP, did not influence cilostazol-induced AMPK phosphorylation. These findings suggest that cilostazol-induced AMPK activation occurs through a signalling pathway independent of cyclic AMP. Cilostazol dose-dependently inhibited LPS-induced NF-kappaB activation in the present study. It was also observed to inhibit LPS-induced iNOS gene promoter activity and iNOS gene expression, resulting in markedly reduced NO production. An AMPK inhibitor compound C or siRNA for AMPK attenuated the observed cilostazol-induced inhibition of NF-kappaB activation by LPS. Ingestion of cilostazol inhibited NF-kappaB activation, as well as the induction of iNOS mRNA and protein expression, within the aortas of LPS-treated rats.

CONCLUSION

In light of these findings, we suggest that cilostazol might attenuate cytokine-induced expression of the iNOS gene by inhibiting NF-kappaB following AMPK activation in VSMC.

The endothelium and vascular inflammation in diabetes

The endothelium releases multiple mediators, not only regulators of vasomotor function but also important physiological and pathophysiological inflammatory mediators. Endothelial dysfunction is caused by chronic exposure to various stressors such as oxidative stress and modified low-density lipoprotein (LDL) cholesterol, resulting in impaired nitric oxide (NO) production and chronic inflammation. Biomechanical forces on the endothelium, including low shear stress from disturbed blood flow and hypertension, are also important causes of endothelial dysfunction. These processes seem to be augmented in patients with diabetes. In states of insulin resistance and in type 2 diabetes insulin signalling is impaired. Increased vascular inflammation, including enhanced expression of interleukin- 6 (IL-6), vascular cellular adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein (MCP- 1) are observed, as is a marked decrease in NO bioavailability. Furthermore, hyperglycaemia leads to increased formation of advanced glycation end products (AGE), which quench NO and impair endothelial function. In summary, during the development of diabetes a number of biochemical and mechanical factors converge on the endothelium, resulting in endothelial dysfunction and vascular inflammation. In the presence of insulin resistance, these processes are potentiated and they provide a basis for the macrovascular disease seen in diabetes.

Cerebrovascular Effects of Cilostazol in Patients With Atherosclerotic Disease

BACKGROUND

Cilostazol is a potent selective inhibitor of phosphodiesterase-3 of proven efficacy in intermittent claudication. It has antiplatelet effect and produces vasodilatation in several vascular territories. This drug has been approved in some countries for the prevention of recurrence of cerebral infarction. Limited data in patients with cerebral infarcts suggest improvement in cerebral blood flow. Dilatation of cerebral vessels with carbon-dioxide challenge can be assessed by transcranial Doppler technique. The percentage increase in blood flow velocity is called cerebral vasomotor reactivity (CVR).

OBJECTIVE

In this investigation we sought to measure CVR before and after oral administration of cilostazol.

METHODS

We studied patients with risk factors for atherosclerosis before they received cilostazol (100 mg twice daily) for intermittent claudication. CVR was assessed by measuring bilateral middle cerebral artery blood flow velocity during normoventilation and after 3 minutes of breathing 8% carbon dioxide. One average value was obtained from each patient. CVR was measured the day before cilostazol first dose, at 1 month, and 3 to 6 months later.

RESULTS

We examined 9 patients (8 men and 1 woman) aged 67.6 +/- 8.4 years. All patients had hypertension, 5 had diabetes, 4 were smokers, 5 had high cholesterol levels, and 4 had coronary artery disease. CVR was 54.4 +/- 14.4% at baseline, and increased to 64.2 +/- 18.6% after 1 month (P < .05) and to 67.1 +/- 13.3% at 3 to 6 months later (P < .01).

CONCLUSION

Our findings suggest that cilostazol increases CVR in patients with atherosclerotic disease.

Endothelial dysfunction and its role in diabetic vascular disease

When normal endothelial function is shifted to a pathological degree, the foundation is laid for possibly following diseases. This endothelial dysfunction is characterized by a proinflammatory state, reduced vasodilation, and a prothrombotic state. In the continuation this dysfunction is strongly associated cardiovascular morbidity and mortality. Endothelial dysfunction is markedly enhanced in type 2 diabetes providing a major pathophysiological cause for the massively increased cardiovascular risk of diabetic patients. Subsequently future therapeutic approaches for the treatment of diabetic cardiovascular disease should target the dysfunctional endothelium first.

Activation of endothelial nitric oxide synthase by cilostazol via a cAMP/protein kinase A- and phosphatidylinositol 3-kinase/Akt-dependent mechanism

We investigated the effect of cilostazol on nitric oxide (NO) production in human aortic endothelial cells (HAEC). Cilostazol increased NO production in a concentration-dependent manner, and NO production was also increased by other cyclic-AMP (cAMP)-elevating agents (forskolin, cilostamide, and rolipram). Cilostazol increased intracellular cAMP level, and that effect was enhanced in the presence of forskolin. In Western blot analysis, cilostazol increased phosphorylation of endothelial nitric oxide synthase (eNOS) at Ser(1177) and of Akt at Ser(473) and dephosphorylation of eNOS at Thr(495). Cilostazol's regulation of eNOS phosphorylation was reversed by protein kinase A inhibitor peptide (PKAI) and by LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor. Moreover, the cilostazol-induced increase in NO production was inhibited by PKAI, LY294002, and N(G)-nitro-l-arginine methyl ester hydrochloride (l-NAME), a NOS inhibitor. In an in vitro model of angiogenesis, cilostazol-enhanced endothelial tube formation, an effect that was completely attenuated by inhibitors of PKA, PI3K, and NOS. These results suggest that cilostazol induces NO production by eNOS activation via a cAMP/PKA- and PI3K/Akt-dependent mechanism and that this effect is involved in capillary-like tube formation in HAEC.

Cilostazol reduces target lesion revascularization after percutaneous transluminal angioplasty in the femoropopliteal artery

BACKGROUND

Although percutaneous transluminal angioplasty (PTA) is being widely used for the treatment of stenosis of peripheral arteries, the high in-stent restenosis rate (50-60%) in the femoropopliteal artery still remains an unsolved issue. Cilostazol is a unique antiplatelet drug that has vasodilatory effects and inhibits smooth muscle cell proliferation.

METHODS AND RESULTS

A total of 141 consecutive patients scheduled for PTA in the femoropopliteal artery between September 1999 and April 2004 were retrospectively analyzed for the use of cilostazol. Target lesion revascularization (TLR) was defined as repeated PTA in patients who had a recurrence of symptoms with diameter stenosis >50% by angiography. Patient and lesion characteristics were similar between the cilostazol (+) and cilostazol (-) groups. Use of other medications was similar between the groups, except for ticlopidine, which was more frequently used in the cilostazol (-) than in the cilostazol (+) group (15% vs 61%, p<0.01). TLR was significantly reduced in the cilostazol (+) group (12% [8/68] vs 32% [23/73], p<0.01).

CONCLUSIONS

Although this study was retrospective and nonrandomized, the results suggest that cilostazol reduces TLR after PTA in the femoropopliteal artery.

Recovery of platelet function after withdrawal of cilostazol administered orally for a long period

To clarify the recovery of platelet function after abrupt withdrawal of cilostazol, we studied platelet function and cilostazol concentration in elderly who received cilostazol, 100 mg twice a day (200 mg/day), for a long period. After interviewing the time of final cilostazol intake, platelet aggregability was determined with an aggregometer using four different concentrations of adenosine-5'-diphosphate as an inducer, which showed the grading curve (GC) type and platetet aggregatory threshold index (PATI). Serum cilostazol concentration was also determined by high-performance liquid chromatography. The GC type and PATI showed suppressed platelet function until 15 hours after withdrawal in half of patients. Bleeding time measured by the Simplate method was prolonged within 4 hours, but recovered by 12 hours after the withdrawal. Some serum cilostazol concentrations were still high 15 hours after withdrawal, while platelets were inhibited even in patients with low serum concentration of cilostazol. In the group receiving the drug for less than 6 months, PATI correlated with serum cilostazol concentration, but platelets in the long-term administration group (more than 48 months) were suppressed at the low serum cilostazol concentration. These findings indicated that platelet function recovered within 12-16 hours after withdrawal in these patients.