Low-Dose Phosphodiesterase III Inhibitor Reduces the Vascular Amyloid Burden in Amyloid-β Protein Precursor Transgenic Mice

Efficacy and Safety of Cilostazol in Mild Cognitive Impairment: A Randomized Clinical Trial

Importance

Recent evidence indicates the efficacy of β-amyloid immunotherapy for the treatment of Alzheimer disease, highlighting the need to promote β-amyloid removal from the brain. Cilostazol, a selective type 3 phosphodiesterase inhibitor, promotes such clearance by facilitating intramural periarterial drainage.

Objective

To determine the safety and efficacy of cilostazol in mild cognitive impairment.

Design, Setting, and Participants

The COMCID trial (A Trial of Cilostazol for Prevention of Conversion from Mild Cognitive Impairment to Dementia) was an investigator-initiated, double-blind, phase 2 randomized clinical trial. Adult participants were registered between May 25, 2015, and March 31, 2018, and received placebo or cilostazol for up to 96 weeks. Participants were treated in the National Cerebral and Cardiovascular Center and 14 other regional core hospitals in Japan. Patients with mild cognitive impairment with Mini-Mental State Examination (MMSE) scores of 22 to 28 points (on a scale of 0 to 30, with lower scores indicating greater cognitive impairment) and Clinical Dementia Rating scores of 0.5 points (on a scale of 0, 0.5, 1, 2, and 3, with higher scores indicating more severe dementia) were enrolled. The data were analyzed from May 1, 2020, to December 1, 2020.

Interventions

The participants were treated with placebo, 1 tablet twice daily, or cilostazol, 50 mg twice daily, for up to 96 weeks.

Main Outcomes and Measures

The primary end point was the change in the total MMSE score from baseline to the final observation. Safety analyses included all adverse events.

Results

The full analysis set included 159 patients (66 [41.5%] male; mean [SD] age, 75.6 [5.2] years) who received placebo or cilostazol at least once. There was no statistically significant difference between the placebo and cilostazol groups for the primary outcome. The least-squares mean (SE) changes in the MMSE scores among patients receiving placebo were -0.1 (0.3) at the 24-week visit, -0.8 (0.3) at 48 weeks, -1.2 (0.4) at 72 weeks, and -1.3 (0.4) at 96 weeks. Among those receiving cilostazol, the least-squares mean (SE) changes in MMSE scores were -0.6 (0.3) at 24 weeks, -1.0 (0.3) at 48 weeks, -1.1 (0.4) at 72 weeks, and -1.8 (0.4) at 96 weeks. Two patients (2.5%) in the placebo group and 3 patients (3.8%) in the cilostazol group withdrew owing to adverse effects. There was 1 case of subdural hematoma in the cilostazol group, which may have been related to the cilostazol treatment; the patient was successfully treated surgically.

Conclusions and Relevance

In this randomized clinical trial, cilostazol was well tolerated, although it did not prevent cognitive decline. The efficacy of cilostazol should be tested in future trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT02491268.

Amyloid-β: Structure, Function, and Pathophysiological Significance in Neurodegenerative Diseases

The rate of dementia continues to increase worldwide; however, there currently exist no therapeutic strategies for this condition [...]

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.

The association between toxic pesticide environmental exposure and Alzheimer's disease: A scientometric and visualization analysis

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. The association between environmental factors (e.g., pesticide) and AD has attracted considerable attention. However, no systematic analysis has been performed and make it difficult to provide deeper insights of AD correlated with pesticide exposure. Hence, this study utilized a bibliometric and visual approach that included map collaborations, co-citations, and keywords, to identifying the knowledge structure, hot topics and the research trends based on 372 publications from the Web of Science Core Collection and PubMed databases. The results showed that 116 institutions from 52 countries published articles in this field. The United States and Israel played a leading role with numerous publications in related journals, as well as prolific institutions and authors, respectively. Three hot topics in pesticide-induced AD were recognized based on co-occurrence keywords detection, including acetylcholinesterase (AChE) inhibitor, oxidative stress, and AChE. Moreover, analysis of keywords burst suggests that some potential molecular mechanisms and therapy targets of pesticide-induced AD, especially for mitochondrial dysfunction and monoamine oxidase-B (MAO-B) that catalyzes the oxidative deamination and causes oxidative stress, are emerging trends. In addition, the study of various pesticides and the assessment method of pesticide exposure will step forward as well. To the best of our knowledge, this study is the first to specifically visualize the relationship between AD and pesticide exposure and to predict potential future research directions.

[Trends and challenges in clinical research on cerebral small vessel disease, with a particular emphasis on type-1 small vessel disease]

Cerebral small vessel disease (SVD) is defined as difficulty maintaining efficient microcirculation, metabolism, and neural networks caused by degeneration of small vessels of the brain, as well as cognitive or physical dysfunction caused by this difficulty. The most common SVD (i.e., type 1 SVD), which is driven by hypertensive arteriopathy, appears to be more prevalent in people with East Asian ethnicity than in Whites. Recent attention has been paid to a SVD scoring system using major MRI markers of SVD in an attempt to comprehensively semi-quantify the SVD burden in the brain. This concept raised a new question: "Is there a practical threshold for the comprehensive SVD score?" The development of computational methods to assess SVD imaging markers could answer this question, and may help identify the optimal intervention for patients with type 1 SVD to prevent stroke and dementia.