Pharmacodynamic of cilostazol for anti-altitude hypoxia

OBJECTIVES

The plateau environment is characterized by low oxygen partial pressure, leading to the reduction of oxygen carrying capacity in alveoli and the reduction of available oxygen in tissues, and thus causing tissue damage. Cilostazol is a phosphodiesterase III inhibitor that has been reported to increase the oxygen release of hemoglobin (Hb) in tissues. This study aims to explore the anti-hypoxic activity of cilostazol and its anti-hypoxic effect.

METHODS

A total of 40 male BALB/C mice were randomly divided into a low-dose cilostazol (6.5 mg/kg) group, a medium-dose (13 mg/kg) group, a high-dose (26 mg/kg) group, and a control group. The atmospheric airtight hypoxia experiment was used to investigate the anti-hypoxic activity of cilostazol and to screen the optimal dosage. Twenty-four male Wistar rats were randomly divided into a normoxia control group, a hypoxia model group, an acetazolamide (22.33 mg/kg) group, and a cilostazol (9 mg/kg) group. After 3 days of hypoxia in the 4 010 m high altitude, blood from the abdominal aorta was collected to determine blood gas indicators, the levels of IL-6 and TNF-α in plasma were determined by enzyme-linked immunosorbent assay, and the levels of malondialdehyde (MDA), superoxide dismutase (SOD), and glutataione (GSH) were measured. The degree of pathological damage for rat tissues was observed with HE staining.

RESULTS

Compared with the control group, the survival time of mice in the low, medium, and high dose group of cilostazol was significantly prolonged, and the survival time of mice in the medium dose group was the longest, with an extension rate at 29.34%, so the medium dose was the best dose. Compared with the hypoxia model group, the P50 (oxygen partial pressure at Hb oxygen saturation of 50%) value of rats in the cilostazol group was significantly increased by 1.03%; Hb and Hct were significantly reduced by 8.46% and 8.43%, and the levels of IL-6 and TNF-α in plasma were reduced by 50.65% and 30.77%. The MDA contents in heart, brain, lung, liver, and kidney tissues were reduced by 37.12%, 29.55%, 25.00%, 39.34%, and 21.47%, respectively. The SOD activities were increased by 94.93%, 9.14%, 9.42%, 13.29%, and 20.80%, respectively. The GSH contents were increased by 95.24%, 28.62%, 28.57%, 20.80%, and 44.00%, respectively. The results of HE staining showed that compared with the hypoxia model group, cilostazol significantly improved the damage of heart, lung, and kidney tissues in rats after hypoxia.

CONCLUSIONS

Cilostazol can significantly improve the oxidative stress and inflammatory reaction caused by rapid altitude hypoxia, and it has a significant protective effect on tissue damage caused by hypoxia, suggesting that it has obvious anti-hypoxic activity.

TLR4/NF-κB/TNFα and cAMP/SIRT1 signaling cascade involved in mediating the dose-dependent effect of cilostazol in ovarian ischemia reperfusion-induced injury

BACKGROUND

One of the most dangerous gynecological emergencies is ovarian ischemia that commonly occurs during surgical manipulation or presence of ovarian masses.

OBJECTIVES

finding new therapies to prevent the associated harmful effects of ischemia/reperfusion-induced damage is still a critical need. For the first time, we aimed to evaluate the possible role of phosphodiesterase (PDE) 3 A inhibitor (PDEI), cilostazol (CLZ) in the treatment of ovarian ischemia reperfusion induced damage (OIR).

METHODS

Rats were divided into five groups; sham, OIR group; CLZ (5, 10, 20 mg/kg) was given orally with induced OIR. Different biochemical parameters were detected such as total anti-oxidant capacity (TAC), reduced glutathione (GSH), malondialdehyde (MDA), cyclic adenosine monophosphate (cAMP), sirtuin1 (SIRT1), toll like receptor 4 (TLR4), nuclear factor kappa b (NF-κB) and tumor necrosis factor alpha (TNFα). In addition, histopathological features, ovarian weight changes and casapse3 immunoexpression were detected.

RESULTS

Data revealed significant increase in ovarian weight changes, MDA, TLR4, TNFα, NF-κB and caspase 3 expressions in OIR induced group. Moreover, OIR group had histopathological features of ovarian damage with depletion of cAMP, SIRT1, TAC and GSH.

CONCLUSION

CLZ could ameliorate OIR-induced damage due to PDE inhibition, anti-oxidant, anti-inflammatory and anti-apoptotic properties with modulation of TLR4/NF-κB/TNFα and cAMP/SIRT1 signaling pathways.

Cilostazol combined with P2Y12 receptor inhibitors: A substitute antiplatelet regimen for aspirin-intolerant patients undergoing percutaneous coronary stent implantation

Background

Cilostazol combined with P2Y₁₂ receptor inhibitor has been used as a substitute regimen for aspirin‐intolerant patients undergoing percutaneous coronary stent implantation on a small scale. Its exact impact on platelet functions and clinical benefits of aspirin‐intolerant patients is unknown.

Hypothesis

Cilostazol combined with P2Y₁₂ receptor inhibitors could be used as a substitute antiplatelet regimen for aspirin‐intolerant patients undergoing percutaneous coronary stent implantation.

Methods

In this multicenter prospective cohort trial, patients undergoing elective percutaneous coronary stent implantation were assigned to the cilostazol group (cilostazol plus P2Y₁₂ receptor inhibitors), based on aspirin intolerance criteria, or the aspirin group (aspirin plus P2Y₁₂ receptor inhibitors). Platelet PAC‐1, CD62p, and vasodilator‐stimulated phosphoprotein phosphorylation (VASP‐P) were detected by flow cytometry. The primary endpoints were major adverse cardiovascular and cerebrovascular events (MACCE) including all‐cause death, acute myocardial infarction, emerging arrhythmia, nonfatal stroke, and heart failure. The secondary endpoints were the Bleeding Academic Research Consortium (BARC) bleeding events.

Results

One hundred and fifty‐four aspirin‐intolerant percutaneous coronary stent implantation patients and 154 matched aspirin‐tolerant patients from a total of 2059 percutaneous coronary stent implantation patients were enrolled. The relative activation level of PAC‐1, CD62p, and platelet reaction index reflected by the VASP‐P test were similar in the two groups (p > .05). After 12 months of follow‐up, the incidence of all‐cause death was 1.9% in the cilostazol group and 1.3% in the aspirin group (risk ratio [RR], 1.500; 95% confidence interval [CI], 0.254–8.852; p = 1.000); the incidence of acute myocardial infarction was 0.6% in the cilostazol group and 1.3% in the aspirin group (RR, 0.500; 95% CI, 0.046–5.457; p = 1.000). No significant difference was seen in other MACCE events, or in any types of BARC bleeding events.

Conclusions

Cilostazol combined with P2Y₁₂ inhibitors was not inferior to aspirin‐based standard therapy and could be used as a reasonable substitute antiplatelet regimen for aspirin‐intolerant patients undergoing percutaneous coronary stent implantation, but again with limitations, which required a larger sample and longer follow‐up to confirm its efficacy.

Our Efforts for Ideal Stroke Prevention and Treatment in Japan

In the present short review for the Sherman Award, Dr Yamaguchi introduces studies at the National Cerebral and Cardiovascular Center, Osaka, which included development of intravenous thrombolysis using low-dose alteplase that was officially approved in Japan, long-term dual antiplatelet therapy using cilostazol together with aspirin or clopidogrel, and others. He also discusses efforts to ensure the passage of the "Stroke and Cardiovascular Disease Control Act," the aims of which are better primary prevention, better acute treatment, rehabilitation, and secondary prevention of stroke for people living in Japan.

Effects of Cilostazol and Isosorbide Mononitrate on Cerebral Hemodynamics in the LACI-1 Randomized Controlled Trial

Supplemental Digital Content is available in the text.

Cerebral small vessel disease—a major cause of stroke and dementia—is associated with cerebrovascular dysfunction. We investigated whether short-term isosorbide mononitrate (ISMN) and cilostazol, alone or in combination, improved magnetic resonance imaging–measured cerebrovascular function in patients with lacunar ischemic stroke.

Double-blind, randomized, placebo-controlled pilot study of the phosphodiesterase-3 inhibitor cilostazol as an adjunctive to antidepressants in patients with major depressive disorder

AIMS

Cilostazol (CLS) has shown antidepressant effect in cardiovascular patients, post-stroke depression, and animal models through its neurotrophic and antiinflammatory activities. Consequently, we aimed to investigate its safety and efficacy in patients with MDD by conducting double-blind, randomized, placebo-controlled pilot study.

METHODS

80 participants with MDD (DSM-IV criteria) and Hamilton Depression Rating Scale (HDRS) score >20 were treated with CLS 50 mg or placebo twice daily plus escitalopram (ESC) 20 mg once daily for six weeks. Patients were evaluated by HDRS scores (weeks 0, 2, 4, and 6). Serum levels of CREB1, BDNF, 5-HT, TNF-α, NF- κB, and FAM19A5 were assessed pre- and post-treatment.

RESULTS

Co-administration of CLS had markedly decreased HDRS score at all-time points compared to the placebo group (p < 0.001). Early improvement, response, and remission rates after 6 weeks were significantly higher in the CLS group (90%, 90%, 80%, respectively) than in the placebo group (25%, 65%, 50% respectively) (p < 0.001). Moreover, the CLS group was superior to the placebo group in modulation of the measured neurotrophic and inflammatory biomarkers.

CONCLUSION

CLS is safe and effective short-term adjunctive therapy in patients with MDD with no other comorbid conditions. Trial registration ID:NCT04069819.

A Systematic Approach to the Development of Cilostazol Nanosuspension by Liquid Antisolvent Precipitation (LASP) and Its Combination with Ultrasound

Nanosizing is an approach to improve the dissolution rate of poorly soluble drugs. The first aim of this work was to develop nanosuspension of cilostazol with liquid antisolvent precipitation (LASP) and its combination with ultrasound. Second, to systematically study the effect of bottom-up processing factors on precipitated particles’ size and identify the optimal settings for the best reduction. After solvent and stabilizer screening, in-depth process characterization and optimization was performed using Design of Experiments. The work discusses the influence of critical factors found with statistical analysis: feed concentration, stabilizer amount, stirring speed and ultrasound energy governed by time and amplitude. LASP alone only generated particle size of a few microns, but combination with ultrasound was successful in nanosizing (d10 = 0.06, d50 = 0.33, d90 = 1.45 µm). Micro- and nanosuspension’s stability, particle morphology and solid state were studied. Nanosuspension displayed higher apparent solubility than equilibrium and superior dissolution rate over coarse cilostazol and microsuspension. A bottom-up method of precipitation-sonication was demonstrated to be a successful approach to improve the dissolution characteristics of poorly soluble, BCS class II drug cilostazol by reducing its particle size below micron scale, while retaining nanosuspension stability and unchanged crystalline form.

Cilostazol Versus Aspirin on White Matter Changes in Cerebral Small Vessel Disease: A Randomized Controlled Trial

BACKGROUND AND PURPOSE

Cerebral small vessel disease is characterized by progressive cerebral white matter changes (WMCs). This study aimed to compare the effects of cilostazol and aspirin on changes in WMC volume in patients with cerebral small vessel disease.

METHODS

In a multicenter, double-blind, randomized controlled trial, participants with moderate or severe WMCs and at least one lacunar infarction detected on brain magnetic resonance imaging were randomly assigned to the cilostazol and aspirin groups in a 1:1 ratio. Cilostazol slow release (200 mg) or aspirin (100 mg) capsules were administered once daily for 2 years. The primary outcome was the change in WMC volume on magnetic resonance images from baseline to 2 years. Secondary imaging outcomes include changes in the number of lacunes or cerebral microbleeds, fractional anisotropy, and mean diffusivity on diffusion tensor images, and brain atrophy. Secondary clinical outcomes include all ischemic strokes, all ischemic vascular events, and changes in cognition, motor function, mood, urinary symptoms, and disability.

RESULTS

Between July 2013 and August 2016, 256 participants were randomly assigned to the cilostazol (n=127) and aspirin (n=129) groups. Over 2 years, the percentage of WMC volume to total WM volume and the percentage of WMC volume to intracranial volume increased in both groups, but neither analysis showed significant differences between the groups. The peak height of the mean diffusivity histogram in normal-appearing WMs was significantly reduced in the aspirin group compared with the cilostazol group. Cilostazol significantly reduced the risk of ischemic vascular event compared with aspirin (0.5 versus 4.5 cases per 100 person-years; hazard ratio, 0.11 [95% CI, 0.02-0.89]).

CONCLUSIONS

There was no significant difference between the effects of cilostazol and aspirin on WMC progression in patients with cerebral small vessel disease. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01932203.

Impact of Cilostazol Pharmacokinetics on the Development of Cardiovascular Side Effects in Patients with Cerebral Infarction

This study investigated the impact of polymorphisms of metabolic enzymes on plasma concentrations of cilostazol and its metabolites, and the influence of the plasma concentrations and polymorphisms on the cardiovascular side effects in 30 patients with cerebral infarction. Plasma concentrations of cilostazol and its active metabolites, and CYP3A5*3 and CYP2C19*2 and *3 genotypes were determined. The median plasma concentration/dose ratio of OPC-13213, an active metabolite by CYP3A5 and CYP2C19, was slightly higher and the median plasma concentration rate of cilostazol to OPC-13015, another active metabolite by CYP3A4, was significantly lower in CYP3A5*1 carriers than in *1 non-carriers (p = 0.082 and p = 0.002, respectively). The CYP2C19 genotype did not affect the pharmacokinetics of cilostazol. A correlation was observed between changes in pulse rate from the baseline and plasma concentrations of cilostazol (R = 0.539, p = 0.002), OPC-13015 (R = 0.396, p = 0.030) and OPC-13213 (R = 0.383, p = 0.037). A multiple regression model, consisting of factors of the plasma concentration of OPC-13015, levels of blood urea nitrogen, and pulse rate at the start of the therapy explained 55.5% of the interindividual variability of the changes in pulse rate. These results suggest that plasma concentrations of cilostazol and its metabolites are affected by CYP3A5 genotypes, and plasma concentration of OPC-13015, blood urea nitrogen, and pulse rate at the start of therapy may be predictive markers of cardiovascular side effects of cilostazol in patients with cerebral infarction.

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.

Dual Antiplatelet Therapy Using Cilostazol in Patients With Stroke and Intracranial Arterial Stenosis

Background Long-term benefit of dual antiplatelet therapy (DAPT) over single antiplatelet therapy (SAPT) for the prevention of recurrent stroke has not been established in patients with intracranial arterial stenosis. We compared the efficacy and safety of DAPT with cilostazol and clopidogrel or aspirin to those of SAPT with clopidogrel or aspirin in patients with intracranial arterial stenosis, who were recruited to the Cilostazol Stroke Prevention Study for Antiplatelet Combination trial, a randomized controlled trial in high-risk Japanese patients with ischemic stroke. Methods and Results We compared the vascular and hemorrhagic events between DAPT and SAPT in patients with ischemic stroke and symptomatic or asymptomatic intracranial arterial stenosis of at least 50% in a major intracranial artery. Patients were placed in two groups: 275 were assigned to receive DAPT and 272 patients SAPT. The risks of ischemic stroke (hazard ratio [HR], 0.47; 95% CI, 0.23-0.95); and composite of stroke, myocardial infarction, and vascular death (HR, 0.48; 95% CI, 0.26-0.91) were lower in DAPT than SAPT, whereas the risk of severe or life-threatening bleeding (HR, 0.72; 95% CI, 0.12-4.30) did not differ between the 2 treatment groups. Conclusions DAPT using cilostazol was superior to SAPT with clopidogrel or aspirin for the prevention of recurrent stroke and vascular events without increasing bleeding risk among patients with intracranial arterial stenosis after stroke. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01995370.

Cilostazol attenuated prenatal valproic acid-induced behavioural and biochemical deficits in a rat model of autism spectrum disorder

OBJECTIVES

Autism spectrum disorder (ASD) is categorized as a neurodevelopmental disorder, presenting with a variety of aetiological and phenotypical features. Inhibiting the enzyme phosphodiesterase-3 (PDE3) with cilostazol is known to produce beneficial effects in several brain disorders. The pharmacological outcome of cilostazol administration was investigated in prenatal valproic acid (VPA)-induced ASD deficits in albino Wistar rats.

METHODS

Cilostazol was administered in two doses (30/60 mg/kg) to male rats born of females administered with VPA on gestational day 12. Behavioural assays on locomotion (open field), social interaction, repetitive behaviour (y-maze) and anxiety (elevated plus maze) were performed in all groups. Further, biochemical assessments of markers associated with neuronal function (BDNF, pCREB), inflammation (TNF-α, IL-6, IL-10) and oxidative stress were carried out in frontal cortex, hippocampus, striatum and cerebellum.

KEY FINDINGS

The cilostazol regimen, attenuated prenatal VPA exposure associated hyperlocomotion, social interaction deficits, repetitive behavior, and anxiety. Further, biochemical markers such as BDNF, pCREB, IL-10 and GSH were found to be significantly increased contrary to markers such as TNF-α, IL-6 and TBARS in the assessed brain regions.

CONCLUSIONS

Cilostazol rectified core behavioural traits while producing significant changes to biochemistry in the brain, suggesting benefits of cilostazol administration in experimental models of ASD.

Intensified antiplatelet therapy in patients after percutaneous coronary intervention with high on-treatment platelet reactivity: the OPTImal Management of Antithrombotic Agents (OPTIMA)-2 Trial

High on-treatment platelet reactivity (HOPR) is associated with increased risk of cardiovascular events in patients undergoing percutaneous coronary intervention (PCI). We randomised post-PCI patients with HOPR after 5 days of standard dual antiplatelet therapy (DAPT) to intensified therapy with aspirin 100 mg once daily in combination with either clopidogrel 150 mg once daily, clopidogrel 75 mg once daily plus cilostazol 100 mg twice daily, ticagrelor 90 mg twice daily, or standard therapy with clopidogrel 75 mg once daily (STD) for 1 month, after which all patients were switched to standard DAPT for a further 11 months. The primary outcome was residual HOPR rate at 1 month. We screened 1724 patients with light transmission aggregation studies and randomised 434 with HOPR. At 1 month the proportion of patients with persistent HOPR was significantly lower in the intensified therapy groups compared with STD group. Compared to the group receiving STD therapy, those receiving intensified therapy had significantly lower rate of major adverse cardiovascular events (MACE) at both 1 month and 12 months with no significant increase in bleeding. In patients with post-PCI HOPR, 1 month of intensified antiplatelet therapy provides greater platelet inhibition and improves outcomes without increasing bleeding. Clinical Trial Registration URL: http://www.clinicaltrials.gov; Unique Identifier: NCT01955200.

Cilostazol Induces eNOS and TM Expression via Activation with Sirtuin 1/Krüppel-like Factor 2 Pathway in Endothelial Cells

Cilostazol was suggested to be beneficial to retard in-stent atherosclerosis and prevent stent thrombosis. However, the mechanisms responsible for the beneficial effects of cilostazol are not fully understood. In this study, we attempted to verify the mechanism of the antithrombotic effect of cilostazol. Human umbilical vein endothelial cells (HUVECs) were cultured with various concentrations of cilostazol to verify its impact on endothelial cells. KLF2, silent information regulator transcript-1 (SIRT1), endothelial nitric oxide synthase (eNOS), and endothelial thrombomodulin (TM) expression levels were examined. We found cilostazol significantly activated KLF2 expression and KLF2-related endothelial function, including eNOS activation, Nitric oxide (NO) production, and TM secretion. The activation was regulated by SIRT1, which was also stimulated by cilostazol. These findings suggest that cilostazol may be capable of an antithrombotic and vasculoprotective effect in endothelial cells.

Dual Antiplatelet Therapy Using Cilostazol With Aspirin or Clopidogrel: Subanalysis of the CSPS.com Trial

Supplemental Digital Content is available in the text.

Background and Purpose:

Although dual antiplatelet therapy (DAPT) with aspirin and clopidogrel reduces the recurrence of ischemic stroke while significantly increasing the bleeding events compared with monotherapy, the CSPS.com trial (Cilostazol Stroke Prevention Study combination) showed that DAPT using cilostazol was more effective without the bleeding risk. In the CSPS.com trial, aspirin or clopidogrel was used as the underlying antiplatelet drug. The effectiveness and safety of each combination were examined and clarified.

Methods:

In the CSPS.com trial, a multicenter, open-label, randomized controlled study, patients with high-risk, noncardioembolic ischemic stroke 8 to 180 days after onset treated with aspirin or clopidogrel alone at the discretion of the physician in charge were recruited. Patients were randomly assigned to receive either monotherapy or DAPT using cilostazol and followed for 0.5 to 3.5 years. The primary efficacy outcome was first recurrence of ischemic stroke. The safety outcome was severe or life-threatening bleeding. The analysis was based on the underlying antiplatelet agents.

Results:

A total of 763 patients taking aspirin and 1116 taking clopidogrel were included in the intention-to-treat analysis. Although the clopidogrel group had more risk factors than the aspirin group, the primary efficacy outcome and safety outcome did not differ significantly between the 2 groups. In the aspirin group, the primary efficacy outcome and safety outcome did not differ significantly between the DAPT group and the aspirin-monotherapy group. In the clopidogrel group, the primary end point occurred at a rate of 2.31 per 100 patient-years in the DAPT group and 5.19 per 100 patient-years in the clopidogrel-monotherapy group (hazard ratio, 0.447 [95% CI, 0.258–0.774]). Safety outcome did not differ significantly between groups (0.51 per 100 patient-years versus 0.71 per 100 patient-years, respectively; hazard ratio, 0.730 [95% CI, 0.206–2.588]).

Conclusions:

The combination of cilostazol and clopidogrel significantly reduced the recurrence of ischemic stroke without increasing the bleeding risk in noncardioembolic, high-risk patients.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01995370. URL: https://www.umin.ac.jp/ctr/; Unique identifier: UMIN000012180.

The Protective Effect of Cilostazol in Genotoxicity Induced by Methotrexate in Human Cultured Lymphocytes

BACKGROUND

Methotrexate is an antagonist of folic acid that has been shown to be genotoxic to healthy body cells via induction of oxidative stress. Cilostazol is a phosphodiesterase III inhibitor and a potent antioxidant drug.

OBJECTIVE

To evaluate the potential protective effect of cilostazol on methotrexate genotoxicity.

METHODS

The genotoxic effect of methotrexate by measuring the frequency of chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs) in human cultured lymphocytes was studied.

RESULTS

Methotrexate significantly increased the frequency of CAs and SCEs (p < 0.0001) as compared to control cultures. This chromosomal damage induced by methotrexate was considerably decreased by pretreatment of the cells with cilostazol (P < 0.01). Moreover, the results showed that methotrexate resulted in a notable reduction (P < 0.01) in cells kinetic parameters, the mitotic index (MI) and the proliferative index (PI). Similarly, cilostazol significantly reduced the mitotic index, which could be related to the anti-proliferative effect (P < 0.01).

CONCLUSION

Methotrexate is genotoxic, and cilostazol could prevent the methotrexate-induced chromosomal damage with no modulation of methotrexate-induced cytotoxicity.

[Pharmacokinetics/Pharmacodynamic Analysis to Link Pharmacokinetics to Efficacy and Drug Interaction of Alzheimer's Disease Drugs]

In recent years, the number of patients with Alzheimer's type dementia continues to increase year by year. As a first-line drug, cholinesterase inhibitor is used. There is a close relationship between the time course of the drug plasma concentration (pharmacokinetics; PK) and the time course of its effects and side effects (pharmacodynamics; PD). However, the relationship between PK and PD is not simply that plasma concentrations are proportional to the effects. The effect is expressed through the characteristics of various pharmacokinetic processes. Therefore, it is important to investigate the transition of effects accompanying its pharmacokinetics. We conducted a fundamental PK/PD analysis using donepezil. Time course of acetylcholine in the hippocampus was investigated with relation to its PK after donepezil administration using rats. The PK and PD characteristics of the drug, including its active metabolite, were investigated. Additionally, Alzheimer's type dementia drugs are often given in combination with antiplatelet drugs such as cilostazol. It is reported that donepezil and cilostazol interact clinically, partly due to inhibition in the efflux transporters in certain tissues. There are various transporters in the body, and interactions through them may cause unexpected changes in the effects. So, it is important to calculate the correlation between the donepezil level in plasma and tissues after their combined administration. From the PK/PD point of view, the results of this study will provide insight into the time course of effects and the characteristics of drug-drug interaction in clinical practice.

Conversion from cilostazol to OPC-13015 linked to mitigation of cognitive impairment

INTRODUCTION

Cilostazol may be a novel therapeutic agent for Alzheimer's disease. Its metabolite, OPC-13015, has a stronger inhibitory effect on type 3 phosphodiesterase than cilostazol.

METHODS

We prospectively enrolled patients with mild cognitive impairment to whom cilostazol was newly prescribed. Patients underwent the Montreal Cognitive Assessment (MoCA) twice, at a 6-month interval. Plasma cilostazol, OPC-13015, OPC-13213, and OPC-13217 concentrations were determined using liquid chromatography-tandem mass spectrometry.

RESULTS

MoCA score changes from baseline to the 6-month visit were positively correlated with ratios of OPC-13015 to cilostazol and total metabolites (n = 19, P = .005). Patients with higher ratios of OPC-13015 (≥0.18, median value; n = 10) had significantly higher MoCA scores (P = .036) than patients with lower ratios (the ratio <0.18, n = 9). The absolute value of OPC-13015 concentration in blood was also higher in patients with preserved cognitive function (P = .033).

DISCUSSION

Blood OPC-13015 levels may be a predictive biomarker of cilostazol treatment for Alzheimer's disease.

Repurposing Cilostazol for Raynaud's Phenomenon

Raynaud 's Phenomenon (RP) results from exaggerated cold-induced vasoconstriction. RP patients suffer from vasospastic attacks and compromised digital blood perfusion leading to a triple color change at the level the fingers. Severe RP may cause ulcers and threaten tissue viability. Many drugs have been used to alleviate the symptoms of RP. These include calcium-channel blockers, cGMP-specific phosphodiesterase type 5 inhibitors, prostacyclin analogs, and angiotensin receptor blockers. Despite their variety, these drugs do not treat RP but rather alleviate its symptoms. To date, no drug for RP has been yet approved by the U.S Food and Drugs Administration. Cilostazol is a selective inhibitor of phosphodiesterase-III, originally prescribed to treat intermittent claudication. Owing to its antiplatelet and vasodilating properties, cilostazol is being repurposed as a potential drug for RP. This review focuses on the different lines of action of cilostazol serving to enhance blood perfusion in RP patients.

A new simple method for quantification of cilostazol and its active metabolite in human plasma by LC-MS/MS: Application to pharmacokinetics of cilostazol associated with CYP genotypes in healthy Chinese population

A simple, sensitive, and fully automated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous quantification of cilostazol (CIL) and its active metabolite, 3,4-dehydro cilostazol (CIL-M), in human plasma. Plasma samples were processed by protein precipitation in 2 mL 96-deep-well plates, and all liquid transfer steps were performed through robotic liquid handling workstation, enabling the whole procedure fast, compared to the reported methods. Separation of analytes was successfully achieved on a UPLC BEH C₁₈ column (2.1 × 100 mm, 1.7 μm) with mobile phase A (5 mM ammonium formate containing 0.1% formic acid) and mobile phase B (methanol) at a flow rate of 0.30 mL min^-1 . The total run time was 3.5 min per sample. Mass spectrometric detection was conducted by electrospray ion source in positive ion multiple reaction monitoring mode. Calibration curves were linear over the concentration range of 1.0-800 ng·mL^-1 for CIL and 0.05-400 ng·mL^-1 for CIL-M. The coefficient of variation for the assay's precision was 12.3%, and the accuracy was 88.8-99.8%. It was fully validated and successfully applied to assess the influence of CYP genotypes on the pharmacokinetics of CIL after oral administration of 50 mg tablet formulations of CIL to healthy Chinese volunteers. The results suggest that, in Chinese population, the genotype of CYP3A5 affects the plasma exposure of CIL.

Network Meta-Analysis Comparing the Outcomes of Treatments for Intermittent Claudication Tested in Randomized Controlled Trials

Background No network meta-analysis has considered the relative efficacy of cilostazol, home exercise therapy, supervised exercise therapy (SET), endovascular revascularization (ER), and ER plus SET (ER+SET) in improving maximum walking distance (MWD) over short- (<1 year), moderate- (1 to <2 years), and long-term (≥2 years) follow-up in people with intermittent claudication. Methods and Results A systematic literature search was performed to identify randomized controlled trials testing 1 or more of these 5 treatments according to Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. The primary outcome was improvement in MWD assessed by a standardized treadmill test. Secondary outcomes were adverse events and health-related quality of life. Network meta-analysis was performed using the gemtc R statistical package. The Cochrane collaborative tool was used to assess risk of bias. Forty-six trials involving 4256 patients were included. At short-term follow-up, home exercise therapy (mean difference [MD], 89.4 m; 95% credible interval [CrI], 20.9-157.7), SET (MD, 186.8 m; 95% CrI, 136.4-237.6), and ER+SET (MD, 326.3 m; 95% CrI, 222.6-430.6), but not ER (MD, 82.5 m; 95% CrI, -2.4 to 168.2) and cilostazol (MD, 71.1 m; 95% CrI, -24.6 to 167.9), significantly improved MWD (in meters) compared with controls. At moderate-term follow-up, SET (MD, 201.1; 95% CrI, 89.8-318.3) and ER+SET (MD, 368.5; 95% CrI, 195.3-546.9), but not home exercise therapy (MD, 99.4; 95% CrI, -174.0 to 374.9) or ER (MD, 84.2; 95% CrI, -35.3 to 206.4), significantly improved MWD (in meters) compared to controls. At long-term follow-up, none of the tested treatments significantly improved MWD compared to controls. Adverse events and quality of life were reported inconsistently and could not be meta-analyzed. Risk of bias was low, moderate, and high in 4, 24, and 18 trials respectively. Conclusions This network meta-analysis suggested that SET and ER+SET are effective at improving MWD over the moderate term (<2 year) but not beyond this. Durable treatments for intermittent claudication are needed.

Transdermal System Based on Solid Cilostazol Nanoparticles Attenuates Ischemia/Reperfusion-Induced Brain Injury in Mice

Cilostazol (CIL) exerted a protective effect by promoting blood-brain barrier integrity as well as improving the status of neurological dysfunctions following cerebral ischemia/reperfusion (I/R) injury. We attempted to design a 0.5% CIL carbopol gel using solid nanoparticles (CIL-Ngel), and then investigated the relationships between energy-dependent endocytosis and the skin penetration of CIL-Ngel in this study. In addition, we evaluated whether the CIL-Ngel attenuated I/R-induced brain injury in a middle cerebral artery occlusion (MCAO)/reperfusion model mouse. The particle size of CIL was decreased using a bead mill, and the CIL particles (14.9 × 10¹⁴ particles/0.3 g) in the CIL-Ngel were approximately 50-180 nm. The release of CIL in the CIL-Ngel was higher than that in gel containing CIL powder (CIL-Mgel), and the CIL particles were released from the CIL-Ngel as nanoparticles. In addition, the percutaneous absorption of CIL from the CIL-Ngel was higher in comparison with that from CIL-Mgel, and clathrin-dependent endocytosis and caveolae-dependent endocytosis were related to the enhanced skin penetration of CIL-NPs. In the traditional (oral administration of CIL powder, 3 mg/kg) and transdermal administration (CIL-Ngel, 0.3 g) for 3 days (once a day), the area under the plasma CIL concentration-time curves (AUC) was similar, although the CIL supplied to the blood by the CIL-Ngel was more sustained than that via oral administration of CIL powder. Furthermore, the CIL-Ngel attenuated the ischemic stroke. In conclusion, we designed a gel using solid CIL-NPs, and we showed that the sustained release of CIL by CIL-Ngel provided an effective treatment for ischemic stroke in MCAO/reperfusion model mice. These findings induce the possibilities of developing novel applications of CIL solid nanoparticles.

[Randomized study of tolerability, safety and efficacy of Pletax in intermittent claudication]

AIM

This study was aimed at assessing tolerability, safety and therapeutic efficacy of Pletax® (cilostazol) compared with Trental® (pentoxifylline) in patients with moderate-to-severe intermittent claudication.

PATIENTS AND METHODS

The study included a total of one hundred 40-to-65-year-old patients presenting with confirmed diagnosis of moderate-to-severe intermittent claudication. Depending on the therapeutic regimen, the patients were divided into two groups. Group 1: 50 patients orally took Pletax® (cilostazol) at a dose of 100 mg twice daily 30 minutes before meals or 2 hours after meals together with conventional therapy. Group 2: 50 patients took oral Trental® (pentoxifylline) in a dose of 400 mg 3 times daily 30 minutes before meals or 2 hours after meals along with conventional therapy. The duration of the follow up period amounted to 24 weeks for both groups. The treadmill test was carried out at room temperature, with the running track tilt angle of 0° at a speed of 3 km/h. The primary parameters of efficacy were as follows: the dynamics of the minimal walking distance (a distance walked by the patient until the appearance of pain in the extremity) and dynamics of the maximal walking distance (a distance walked by the patients until full stop due to pain in the extremity).

RESULTS

Analysing efficacy demonstrated higher results of Pletax® compared with Trental®. The obtained findings suggested that Pletax® showed a significant clinical effect as soon as at 2 weeks, followed by advantage during the whole period of follow up. Analysing the parameters of the minimal and maximal walking distances in the group of patients taking Pletax® demonstrated clear superiority over the Trental® group as soon as by week 2 of administration, which preserved during the whole follow-up period. The minimal pain-free walking distance in the Pletax group at baseline amounted to 92.9±83.4 m (Trental group - 92.3±78.4; p=0.3), followed by an increase at week 8 to 126±115 m (Trental group - 116±96.3; p=0.51), at week 16 to 136±116 m (Trental group - 118±95.5; p=0.04), at week 24 to 149±126 b (Trental group - 127±98.9; p=0.01). At the same time, the effect of Pletax® and Trental® on the secondary parameter of efficacy, i.e., the ankle-brachial index was comparable: at baseline - 0.472 and 0.482 (p=0.28), at 2 weeks - 0.48 and 0.483 (p=031), at 8 weeks - 0.49 and 0.485 (p=0.74), at 16 weeks - 0.494 and 0.492 (p=0.2), at 24 weeks - 0.501 and 0.496 (p=0.45).

CONCLUSION

The obtained findings demonstrated advantages of Pletax® over Trental®, manifesting themselves in the achievement of the highest parameters by such criteria as the minimal and maximal walking distance. High safety and efficacy of Pletax® were confirmed by low frequency of unfavourable events during therapy.

Antiplatelet Therapy in the Secondary Prevention of Non-cardioembolic Ischemic Stroke and Transient Ischemic Attack: A Mini-Review

The aim of this mini-review is to discuss the main antiplatelet agents that have been successfully used in the secondary prevention of non-cardioembolic ischemic stroke and transient ischemic attacks (TIA). The methodology is based on a literature review of available peer-reviewed English studies listed in PubMed. The findings reveal that aspirin remains a reliable antiplatelet agent in the secondary prevention of acute non-cardioembolic ischemic stroke and TIA. Nevertheless, currently, there are also other agents, i.e., ticagrelor, clopidogrel, and cilostazol, that can be applied. In addition, the results indicate that time is significant not only in severe stroke but also in non-severe stroke and TIA, which suggests that antiplatelet therapy should be applied within 24 h after the first symptoms because early treatment can lead to an improvement in neurological outcomes and reduce the chance of an early subsequent stroke.

Association of Antiplatelet Therapy, Including Cilostazol, With Improved Survival in Patients With Moyamoya Disease in a Nationwide Study

Background

Although antiplatelet agents are frequently prescribed in moyamoya disease in routine clinical practice, there are no large‐scale epidemiologic trials or randomized trial evidence to support their use in patients with moyamoya disease.

Methods and Results

Using the Korean National Health Insurance Service database, patients diagnosed with moyamoya disease between 2002 and 2016 were followed up for up to 14 years to assess, using time‐dependent Cox regression in all patients and in a propensity score–matched cohort, the association of antiplatelet therapy and individual antiplatelet agents with survival. Among 25 978 patients with newly diagnosed moyamoya disease, mean age was 37.6±19.9 years, 61.6% were women, and total follow‐up was 163 347 person‐years. Among 9154 patients who were prescribed antiplatelet agents at least once during the follow‐up period, the proportion prescribed cilostazol gradually increased from 5.5% in 2002 to 56.0% in 2016. Any antiplatelet use was associated with reduced risk of death (hazard ratio, 0.77; 95% CI, 0.70–0.84) in a multivariate model. Among individual antiplatelet agents, cilostazol was associated with greater reduction in mortality than the 5 other antiplatelet regimens. Subgroup analysis, according to the age group and history of ischemic stroke, and sensitivity analysis, using propensity score–matched analysis, revealed consistent results.

Conclusions

Antiplatelet therapy is associated with substantial improvement in survival in patients with moyamoya disease, and cilostazol is associated with greater survival benefit compared with other antiplatelet regimens. These results provisionally support the use of antiplatelet therapy in patients with moyamoya disease and the conduct of confirmatory randomized controlled trials.