Effect of cilostazol on vasomotor reactivity in patients with vasospastic angina pectoris

Long-acting cilostazol versus isosorbide mononitrate for patients with vasospastic angina: a randomized controlled trial

BACKGROUND

Cilostazol has a vasodilatory function that may be beneficial for patients with vasospastic angina (VSA). We conducted a randomized, open-label, controlled trial to compare the efficacy and safety of long-acting cilostazol and isosorbide mononitrate (ISMN) for VSA.

METHODS

The study included patients with confirmed VSA between September 2019 and May 2021. Participants were randomly assigned to receive long-acting cilostazol (test group, 200 mg once daily) or conventional ISMN therapy (control group, 20 mg twice daily) for 4 weeks. The clinical efficacy and safety were evaluated using weekly questionnaires.

RESULTS

Forty patients were enrolled in the study (long-acting cilostazol, n  = 20; ISMN, n  = 20). Baseline characteristics were balanced between the two groups. Long acting cilostazol showed better angina symptom control within the first week compared to ISMN [reduction of pain intensity score, 6.0 (4.0-8.0) vs. 4.0 (1.0-5.0), P  = 0.005; frequency of angina symptom, 0 (0-2.0) vs. 2.0 (0-3.0), P  = 0.027, respectively]. The rate of neurological adverse reactions was lower in the cilostazol group than in the ISMN group (headache or dizziness, 40 vs. 85%, P  = 0.009; headache, 30 vs. 70%, P  = 0.027).

CONCLUSION

Long-acting cilostazol provided comparable control of angina and fewer adverse neurologic reactions within 4 weeks compared to ISMN. Long-acting cilostazol provides more intensive control of angina within 1 week, suggesting that it may be an initial choice for the treatment of VSA.

The Role of Cilostazol, a Phosphodiesterase-3 Inhibitor, in the Development of Atherosclerosis and Vascular Biology: A Review with Meta-Analysis

Atherosclerotic cardiovascular disease (ASCVD) stands as the leading global cause of mortality. Addressing this vital and pervasive condition requires a multifaceted approach, in which antiplatelet intervention plays a pivotal role, together with antihypertensive, antidiabetic, and lipid-lowering therapies. Among the antiplatelet agents available currently, cilostazol, a phosphodiesterase-3 inhibitor, offers a spectrum of pharmacological effects. These encompass vasodilation, the impediment of platelet activation and aggregation, thrombosis inhibition, limb blood flow augmentation, lipid profile enhancement through triglyceride reduction and high-density lipoprotein cholesterol elevation, and the suppression of vascular smooth muscle cell proliferation. However, the role of cilostazol has not been clearly documented in many guidelines for ASCVD. We comprehensively reviewed the cardiovascular effects of cilostazol within randomized clinical trials that compared it to control or active agents and involved individuals with previous coronary artery disease or stroke, as well as those with no previous history of such conditions. Our approach demonstrated that the administration of cilostazol effectively reduced adverse cardiovascular events, although there was less evidence regarding its impact on myocardial infarction. Most studies have consistently reported its favorable effects in reducing intermittent claudication and enhancing ambulatory capacity in patients with peripheral arterial disease. Furthermore, cilostazol has shown promise in mitigating restenosis following coronary stent implantation in patients with acute coronary syndrome. While research from more diverse regions is still needed, our findings shed light on the broader implications of cilostazol in the context of atherosclerosis and vascular biology, particularly for individuals at high risk of ASCVD.

Pharmacotherapy in patients with vasomotor disorders

Background

Anginal symptoms in patients with non-obstructive coronary artery disease are frequently related to vasomotor disorders of the coronary circulation. Although frequently overlooked, a distinct diagnosis of different vasomotor disorders can be made by intracoronary function testing. Early detection and treatment seems beneficial, but little evidence is available for the medical treatment of these disorders. Nevertheless, there are several pharmacotherapeutic options available to treat these patients and improve quality of life.

Methods & findings

We performed an extensive yet non-systematic literature search to explore available pharmacotherapeutic strategies for addressing vasomotor disorders in individuals experiencing angina and non-obstructive coronary artery disease. This article presents a comprehensive overview of therapeutic possibilities for patients exhibiting abnormal vasoconstriction (such as spasm) and abnormal vasodilation (like coronary microvascular dysfunction).

Conclusion

Treatment of vasomotor disorders can be very challenging, but a general treatment algorithm based on the existing evidence and the best available current practice is feasible.

Coronary Vasospastic Angina: A Review of the Pathogenesis, Diagnosis, and Management

Vasospastic angina (VSA) is an under-appreciated cause of chest pain. It is characterised by transient vasoconstriction of the coronary arteries and plays a significant role in the pathogenesis of stable angina and acute coronary syndromes. Complex mechanistic pathways characterised by endothelial dysfunction and smooth muscle hypercontractility lead to a broad spectrum of clinical manifestations ranging from recurrent angina to fatal arrhythmias. Invasive provocation testing using intracoronary acetylcholine or ergonovine is considered the current gold standard for diagnosis, but there is a wide variation in protocols amongst different institutions. Conventional pharmacological therapy relies on calcium channel blockers and nitrates; however, refractory VSA has limited options. This review evaluates the pathophysiology, diagnostic challenges, and management strategies for VSA. We believe global efforts to standardise diagnostic and therapeutic guidelines will improve the outcomes for affected patients.

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.

Treatment of coronary microvascular dysfunction

Contemporary data indicate that patients with signs and symptoms of ischaemia and non-obstructive coronary artery disease (INOCA) often have coronary microvascular dysfunction (CMD) with elevated risk for adverse outcomes. Coronary endothelial (constriction with acetylcholine) and/or microvascular (limited coronary flow reserve with adenosine) dysfunction are well-documented, and extensive non-obstructive atherosclerosis is often present. Despite these data, patients with INOCA currently remain under-treated, in part, because existing management guidelines do not address this large, mostly female population due to the absence of evidence-based data. Relatively small sample-sized, short-term pilot studies of symptomatic mostly women, with INOCA, using intense medical therapies targeting endothelial, microvascular, and/or atherosclerosis mechanisms suggest symptom, ischaemia, and coronary vascular functional improvement, however, randomized, controlled outcome trials testing treatment strategies have not been completed. We review evidence regarding CMD pharmacotherapy. Potent statins in combination with angiotensin-converting enzyme inhibitor (ACE-I) or receptor blockers if intolerant, at maximally tolerated doses appear to improve angina, stress testing, myocardial perfusion, coronary endothelial function, and microvascular function. The Coronary Microvascular Angina trial supports invasive diagnostic testing with stratified therapy as an approach to improve symptoms and quality of life. The WARRIOR trial is testing intense medical therapy of high-intensity statin, maximally tolerated ACE-I plus aspirin on longer-term outcomes to provide evidence for guidelines. Novel treatments and those under development appear promising as the basis for future trial planning.

Effects of açaí and cilostazol on skin microcirculation and viability of TRAM flaps in hamsters

BACKGROUND

Tissue necrosis caused by insufficient perfusion is a major complication in flap transfer. This study evaluated whether treatment with cilostazol or hydroalcoholic extract of seeds of Euterpe oleracea Mart. (açaí) protects the transverse rectus abdominis myocutaneous (TRAM) flap against ischemic damage in hamsters.

MATERIALS AND METHODS

Fifty-four hamsters were divided into three oral treatment groups: placebo, açaí, or cilostazol. Caudally based, unipedicled TRAM flaps were raised, sutured back, classified into four vascular zones (I-IV), and evaluated for tissue viability, capillary blood flow (CBF), perfused vessel density (PVD), and microvascular flow index (MFI) by orthogonal polarization spectral imaging at three time points: immediately postoperatively (IPO), 24 h postoperatively (24hPO), and 7 d postoperatively (7POD).

RESULTS

Comparing to placebo, açaí increased PVD at IPO and açaí and cilostazol increased CBF and PVD at 24hPO in zone I; cilostazol increased CBF, PVD, and MFI at IPO, and CBF at 24hPO in zone II; açaí and cilostazol increased CBF at all time points and PVD and MFI at IPO and 24hPO in zone III; cilostazol increased CBF at IPO and 7POD, açaí increased CBF at 7POD, and both increased PVD and MFI at all time points in zone IV; and açaí and cilostazol increased the percentage of viable area in zones III and IV.

CONCLUSIONS

Açaí and cilostazol treatments had a protective effect against ischemic damage to TRAM flaps in hamsters, improving microvascular blood flow and increasing the survival of flap zones contralateral to the vascular pedicle (zones III and IV).

Cilostazol Prevents Atrial Structural Remodeling through the MEK/ERK Pathway in a Canine Model of Atrial Tachycardia

OBJECTIVES

Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice. Atrial structural remodeling (ASR), particularly atrial fibrosis, is an important contributor to the AF substrate. This study aimed to investigate the preventive effects of the phosphodiesterase 3 inhibitor cilostazol on ASR and its potential molecular mechanisms in a canine model of rapid atrial pacing (RAP).

METHODS

Thirty dogs were assigned to sham (Sham), paced/ no treatment (Paced) and paced + cilostazol 5 mg/kg/day (Paced + cilo) groups, with 10 dogs in each group. RAP at 500 beats/min was maintained for 2 weeks, while the Sham group was instrumented without pacing. Cilostazol was provided orally during pacing. Western blotting, RT-PCR and pathology were used to assess ASR.

RESULTS

Cilostazol attenuated atrial interstitial fibrosis and structural remodeling in canines with RAP. MEK/ERK transduction pathway gene expression was upregulated in the Paced group compared with the Sham group. Cilostazol markedly alleviated these changes in the MEK/ERK pathway. Transforming growth factor-β1 protein expression in the Paced group was significantly higher than in the Sham group (p < 0.01), and was significantly reduced by cilostazol (p < 0.01).

CONCLUSIONS

Our findings suggest that cilostazol is beneficial for prevention and treatment in atrial tachycardia-induced ASR in a canine model of RAP.

Cilostazol does not improve peripheral arterial disease-linked oxidative stress

AIM

Cilostazol is a drug widely used to treat peripheral arterial disease (PAD) in patients with advanced atherosclerosis. It is an inhibitor of platelet aggregation and causes arterial vasodilatation. It has been speculated that cilostazol might act to improve oxidative stress in these patients.

METHODS

We analyzed 25 patients with demonstrated lower limb peripheral arterial disease to determine whether lipid peroxidation (LPO) or total antioxidant capacity (TAC) were modified after 6 months of cilostazol treatment (postintervention phase) with respect to the basal phase.

RESULTS

Analysis of plasma samples determined that LPO levels decreased significantly over the postintervention phase (26±15 vs. 11±7 pM, P=0.0003). However, when TAC levels were analyzed, no significant differences were observed (0.80±0.21 vs. 0.85±0.17 mM, P=0.42). Under basal conditions, LPO showed a positive correlation to treatment as judged by the ankle-brachial index (r=0.800, P=0.002) as well as uric acid (r=0.508, P=0.03) and CRP (r=0.481, P=0.05) levels. In contrast, TAC negatively correlated with triglycerides (r=-0.879, P<0.0001) and microalbuminuria (r=-0.868, P<0.0001). In the postintervention phase, TAC negatively correlated with HbA1c (r=-0.570, P=0.02) and triglycerides (r=-0.864, P<0.0001).

CONCLUSIONS

Our data indicate that cilostazol treatment does not improve oxidative stress in PAD patients after 6 months of treatment. However, lipid peroxidation and total antioxidant capacity were affected by cilostrazol treatment, which could be related to altered reactive oxygen species production. Further research may be needed to determine the critical dose of cilostazol to clarify the protective role of this drug in PAD.

Cilostazol ameliorates atrial ionic remodeling in long-term rapid atrial pacing dogs

Objective:

Ionic remodeling has a close correlation with the occurrence of atrial fibrillation (AF). Atrial tachypacing remodeling is associated with characteristic ionic remodeling. The purpose of this study was to assess the efficacy of cilostazol, an oral phosphodiesterase 3 inhibitor, for preventing atrial ionic remodeling in long-term rapid atrial pacing (RAP) dogs.

Methods:

We use the methods of patch-clamp and molecular biology to investigate the effect of cilostazol on ion channel and channel gene expression in long-term RAP dogs. Twenty-one dogs were randomly assigned to sham, control paced, and paced+cilostazol (5 mg/kg/d, cilo) groups, with 7 dogs in each group. The sham group was instrumented with a pacemaker but without pacing. RAP at 500 beats/min was maintained for 2 weeks in the paced and cilo groups. During the pacing, cilostazol was given orally in the cilo group. Whole-cell patch-clamp technique was used to record atrial L-type Ca²+ (I_CaL) and fast sodium channel (I_Na) ionic currents. Western blot and RT-PCR were applied to estimate the gene expression of the I_CaLa) 1C (Cav1.2) and I_Nav1.5a) Nav1.5a) subunits. Statistical analysis was performed using SPSS 13.0.

Results:

The density of I_CaL and I_Na currents (pA/pF) was significantly reduced in the paced group (I_CaL: -6.55±1.42 vs. -4.46±0.59 pA/pF; I_Na: -48.24±10.54 vs. -30.48±5.20 pA/pF, p<0.01). The paced+cilo group could not increase the density of I_CaL currents (I_CaL: -4.37±1.25 pA/pF, p>0.05], while the I_Na currents were recovered (-44.54±12.65 pA/pF, p<0.01) compared with the paced group. The mRNA and protein expression levels of Cav1.2 and Nav1.5a were apparently down-regulated in the paced group (p<0.01), but after cilostazol treatment, both of these subunits were up-regulated significantly (p<0.01).

Conclusion:

Cilostazol may have protective effects on RAP-induced atrial ionic remodeling.

Phosphodiesterase-3 inhibitor (cilostazol) attenuates oxidative stress-induced mitochondrial dysfunction in the heart

Background

Cilostazol is a type 3 phosphodiesterase inhibitor which has been previously demonstrated to prevent the occurrence of tachyarrhythmia and improve defibrillation efficacy. However, the mechanism for this beneficial effect is still unclear. Since cardiac mitochondria have been shown to play a crucial role in fatal cardiac arrhythmias and that oxidative stress is one of the main contributors to arrhythmia generation, we tested the effects of cilostazol on cardiac mitochondria under severe oxidative stress.

Methods

Mitochondria were isolated from rat hearts and treated with H₂O₂ to induce oxidative stress. Cilostazol, at various concentrations, was used to study its protective effects. Pharmacological interventions, including a mitochondrial permeability transition pore (mPTP) blocker, cyclosporine A (CsA), and an inner membrane anion channel (IMAC) blocker, 4′-chlorodiazepam (CDP), were used to investigate the mechanistic role of cilostazol on cardiac mitochondria. Cardiac mitochondrial reactive oxygen species (ROS) production, mitochondrial membrane potential change and mitochondrial swelling were determined as indicators of cardiac mitochondrial function.

Results

Cilostazol preserved cardiac mitochondrial function when exposed to oxidative stress by preventing mitochondrial depolarization, mitochondrial swelling, and decreasing ROS production.

Conclusions

Our findings suggest that cardioprotective effects of cilostazol reported previously could be due to its prevention of cardiac mitochondrial dysfunction caused by severe oxidative stress.

A randomised, multicentre, double blind, placebo controlled trial to evaluate the efficacy and safety of cilostazol in patients with vasospastic angina

OBJECTIVES

We conducted a randomised, double blind, placebo controlled trial to assess the efficacy and safety of cilostazol, a selective inhibitor of phosphodiesterase 3, in patients with vasospastic angina (VSA).

BACKGROUND

Cilostazol has been shown to induce vascular dilatation, but its efficacy in patients with VSA is unknown.

METHODS

Between October 2011 and July 2012, 50 patients with confirmed VSA who had ≥1 angina episodes/week despite amlodipine therapy (5 mg/day) were randomly assigned to receive either cilostazol (up to 200 mg/day) or placebo for 4 weeks. All patients were given diaries to record the frequency and severity of chest pain (0-10 grading). The primary endpoint was the relative reduction of the weekly incidence of chest pain.

RESULTS

Baseline characteristics were similar between the two groups. Among 49 evaluable patients (25 in the cilostazol group, 24 in the placebo group), the primary endpoint was significantly greater in the cilostazol group compared with the placebo group (-66.5±88.6% vs -17.6±140.1%, respectively, p=0.009). The secondary endpoints, including a change in the frequency of chest pain (-3.7±0.5 vs -1.9±0.6, respectively, p=0.029), a change in the chest pain severity scale (-2.8±0.4 vs -1.1±0.4, respectively, p=0.003), and the proportion of chest pain-free patients (76.0% vs 33.3%, respectively, p=0.003) also significantly favoured cilostazol. Headache was the most common adverse event in both groups (40.0% vs 20.8%, respectively, p=0.217).

CONCLUSIONS

Cilostazol is an effective therapy for patients with VSA uncontrolled by conventional amlodipine therapy, and has no serious side effects.

TRIAL REGISTRATION NUMBER

NCT01444885.

Efficacy of cilostazol on uncontrolled coronary vasospastic angina: a pilot study

BACKGROUND

Although an angina attack by vasospastic angina (VSA) can usually be relieved or controlled with nitrates and calcium channel blockers (CCBs), there are some patients who cannot be controlled even by higher doses and combinations of these drugs. Cilostazol is a selective inhibitor of phosphodiesterase 3 that increases intracellular cyclic adenosine monophosphate (cAMP) contents. A stimulation of cAMP signal transduction increases coronary nitric oxide production. We examined whether cilostazol improved angina symptoms in patients with VSA uncontrolled by conventional treatment.

METHODS

This study was conducted in a prospective, multicenter, nonrandomized manner. The subject consisted of 21 patients (13 men, 57 ± 9 year-old) who were diagnosed with VSA and had at least two angina attacks during the past 1 week despite of conventional medications such as CCBs and/or nitrates. They took cilostazol 100 mg twice daily for 2 weeks in addition to the conventional medications. The patients recorded the frequency of angina attack and wrote down the numeric rating scale of a "severity of angina attack" while taking conventional medications and cilostazol for 2 weeks, and also recorded an averaged scale or total number of event during the last week at the time of the assessment. Using the Wilcoxon rank-sum test, we compared the changes in the scores of frequency and severity of angina attack before and after adding cilostazol to the conventional medications.

RESULTS

After adding cilostazol to the conventional medications, there were 78.9% relative reduction of the score of angina intensity and 73.5% of angina frequency (P < 0.001). There were four patients (19%) who were forced to stop cilostazol due to headache as an adverse event.

CONCLUSIONS

Cilostazol appears to be an effective therapy in VSA uncontrolled with conventional medical treatment. A further prospective, randomized, placebo-controlled study will be needed to validate this result.

Differential impact of cilostazol on restenosis according to implanted stent type (from a pooled analysis of three DECLARE randomized trials)

Even in the drug-eluting stent era, restenosis has remained an unresolved issue, particularly in the treatment of complex coronary lesions. In this study, patient-level data from 3 randomized trials (Drug-Eluting Stenting Followed by Cilostazol Treatment Reduces Late Restenosis in Patients With Diabetes Mellitus [DECLARE-DIABETES] and Drug-Eluting Stenting Followed by Cilostazol Treatment Reduces Late Restenosis in Patients With Long Native Coronary Lesions [DECLARE-LONG] I and II) were pooled to estimate the differential antirestenotic efficacy of add-on cilostazol according to the implanted drug-eluting stent in patients at high risk for restenosis. A total of 1,399 patients underwent sirolimus-eluting stent (SES; n = 450), paclitaxel-eluting stent (n = 450), and zotarolimus-eluting stent (n = 499) implantation and received triple-antiplatelet therapy (TAT; aspirin, clopidogrel, and cilostazol, n = 700) and dual-antiplatelet therapy (aspirin and clopidogrel, n = 699). Randomization of antiplatelet regimen was stratified by stent type. In-stent late loss after TAT was significantly lower than that after dual-antiplatelet therapy, regardless of implanted stent type. However, the incidence of in-segment restenosis after TAT was significantly lower with SES (0.5% vs 6.7%, p = 0.014) and zotarolimus-eluting stent (12.2% vs 20.0%, p = 0.028) implantation but not paclitaxel-eluting stent implantation (14.4% vs 20.0%, p = 0.244). A significant interaction was present between stent type and antiplatelet regimen for the risk for in-segment restenosis (p = 0.004). Post hoc analysis using bootstrap resampling methods showed that the relative risk reduction for in-segment restenosis after TAT was most prominent with SES implantation. In conclusion, add-on cilostazol effectively reduced restenosis in patients at high risk for restenosis, particularly in those receiving SES, suggesting the sustainable utility of add-on cilostazol therapy in newer generation drug-eluting stents with comparable efficacy with that of SES.

Effects of cilostazol in the heart

Cilostazol is a selective phosphodiesterase 3 (PDE3) inhibitor approved by the Food and Drug Administration for treatment of intermittent claudication. It has also been used in bradyarrhythmic patients to increase heart rates. Recently, cilostazol has been shown to prevent ventricular fibrillation in patients with Brugada syndrome. Cilostazol is hypothesized to suppress transient outward potassium (Ito) current and increase inward calcium current, thus, maintaining the dome (phase 2) of action potential, decreasing transmural dispersion of repolarization and preventing ventricular fibrillation. Although many PDE3 inhibitors have been shown to increase cardiac arrhythmia in heart failure, cilostazol has presented effects that are different from other PDE3 inhibitors, especially adenosine uptake inhibition. Owing to this effect, cilostazol could be an effective cardioprotective drug, with its beneficial effects in preventing arrhythmia. In this review, the cardiac electrophysiological effects of cilostazol are presented and its possible cardioprotective effects, particularly in preventing ventricular fibrillation, are discussed, with emphasis on the need to further verify its clinical benefits.

Mammalian Cyclic Nucleotide Phosphodiesterases: Molecular Mechanisms and Physiological Functions

The superfamily of cyclic nucleotide (cN) phosphodiesterases (PDEs) is comprised of 11 families of enzymes. PDEs break down cAMP and/or cGMP and are major determinants of cellular cN levels and, consequently, the actions of cN-signaling pathways. PDEs exhibit a range of catalytic efficiencies for breakdown of cAMP and/or cGMP and are regulated by myriad processes including phosphorylation, cN binding to allosteric GAF domains, changes in expression levels, interaction with regulatory or anchoring proteins, and reversible translocation among subcellular compartments. Selective PDE inhibitors are currently in clinical use for treatment of erectile dysfunction, pulmonary hypertension, intermittent claudication, and chronic pulmonary obstructive disease; many new inhibitors are being developed for treatment of these and other maladies. Recently reported x-ray crystallographic structures have defined features that provide for specificity for cAMP or cGMP in PDE catalytic sites or their GAF domains, as well as mechanisms involved in catalysis, oligomerization, autoinhibition, and interactions with inhibitors. In addition, major advances have been made in understanding the physiological impact and the biochemical basis for selective localization and/or recruitment of specific PDE isoenzymes to particular subcellular compartments. The many recent advances in understanding PDE structures, functions, and physiological actions are discussed in this review.

Idiopathic carotid and coronary vasospasm: a new syndrome?

We present the first case of cerebral infarction due to idiopathic reversible vasospasm of the extracranial internal carotid artery without headache or identifiable cause in a patient who subsequently suffered acute myocardial infarction due to vasospasm of the coronary artery.

Effects of cilostazol and pentoxifylline on forearm reactive hyperemia response, lipid profile, oxidative stress, and inflammatory markers in patients with intermittent claudication

Peripheral arterial disease may lead to lower limb claudication and increased risk of systemic vascular dysfunction. In this article, the authors have investigated the peripheral vascular dysfunction evaluating forearm blood flow using venous occlusion plethysmography, lipid profile, and C-reactive protein in 60 patients with moderate intermittent claudication treated during 20 weeks with placebo (n = 16), cilostazol (200 mg/d; n = 17), or pentoxifylline (1200 mg/d; n = 15) in a randomized double-blinded clinical trial, taking into account smoking. Forearm blood flow after reactive hyperemia response (FBF(h) ) or oral nitroglycerine spray to evaluate endothelial-dependent and endothelial-independent vasodilation, respectively, pain-free and maximal walking distance, levels of C-reactive protein, triglycerides, cholesterol, low-density lipoprotein, and high-density lipoprotein-cholesterol in plasma were determined. The results showed that there was an improvement in the high-density lipoprotein-cholesterol, pain-free and maximal walking distance, and FBF(h) independent of treatment in nonsmoking patients. Cilostazol increased high-density lipoprotein-cholesterol level, maximal walking distance, and FBF(h), whereas pentoxifylline reduced C-reactive protein level and increased maximal walking distance in total and nonsmoking groups. No treatment was effective in smokers.

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.

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.

Effects of cilostazol in patients with Raynaud's syndrome

Raynaud's syndrome (RS), which is characterized by recurrent episodes of vasospasm with exposure to cold, may occur alone (primary RS) or in association with connective tissue diseases or other underlying conditions (secondary RS). We investigated the effect of cilostazol on vessel wall responses in RS. Patients were diagnosed (primary or secondary RS associated with connective tissue diseases) and randomized to placebo or cilostazol 100 mg twice daily for 6 weeks in a double-blind manner. Brachial artery vasoreactivity, laser Doppler fluxmetry, and cold pressor testing (CPT) were performed at study initiation and completion. Symptoms were assessed using standardized questionnaires. Forty subjects completed the study (19 with primary RS and 21 with secondary RS). Cilostazol significantly increased the mean brachial artery diameter at 6 weeks (primary RS, p = 0.006; secondary RS, p = 0.06). There was no change in median flow-mediated dilation (FMD) with cilostazol in primary RS (25th, 75th percentiles) (4.06% [2.5, 6.1] to -0.77% [-2.4, 3.4] or secondary RS (2.2% [0.05, 6.3] to 2.95% [1.7, 7.4]). There were no changes in nitroglycerin-mediated dilation or microvascular flow indexes in either cohort. In patients with primary RS, cilostazol treatment yielded a positive change in the slope of brachial responsiveness to CPT (increase of 0.32 mm/min; p = 0.002 vs placebo). Cilostazol treatment remained significantly associated with increased brachial artery diameter when controlling for baseline values (p = 0.018). Cilostazol increased conduit vessel diameter in patients with primary and secondary RS, with a favorable impact on conduit vessel responsiveness to cold in patients with primary RS without affecting microvascular flow or symptoms.