Takumi Imai

Dr. Takumi Imai

orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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6 March 2017 in Osteoporosis International
Verified
Journal Article
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TITakumi Imai
Takumi Imai
FGfor the A-TOP (Adequate Treatment of Osteoporosis) Research Group
for the A-TOP (Adequate Treatment of Osteoporosis) Research Group
STS. Tanaka
S. Tanaka
KKKoji Kawakami
Koji Kawakami
TMT. Miyazaki
T. Miyazaki
MSMasataka Shiraki
Masataka Shiraki

1 October 2023 in Hypertension
Verified
Journal Article
Closed access
HTHirofumi Tomiyama
Hirofumi Tomiyama
TITakumi Imai
Takumi Imai
KSKazuki Shiina
Kazuki Shiina
YHYukihito Higashi
Yukihito Higashi
HNHiroki Nakano
Hiroki Nakano
TCTaishiro Chikamori
Taishiro Chikamori
Background: Although some cardiovascular risk factors (CVRFs) are known to be associated with increased arterial stiffness, increased arterial stiffness does not mediate the cardiovascular risk associated with all CVRFs. Here, based on long-term repeated-measurement data, we examined the association of the lifelong status of each CVRF with the rate of progression of arterial stiffness. Methods: We utilized the data from annual health checkups with the brachial-ankle pulse wave velocity measurements over a 16-year period in middle-aged Japanese occupational cohort. Results: Totally, 29 090 brachial-ankle pulse wave velocity data were obtained during the follow-up of 3763 subjects ranging in age from around 30 to 70 years. Smoking, heavy alcohol intake, hypertension, diabetes, hypertriglyceridemia, and hyperuricemia were independently associated with the fast progression of arterial stiffness. Also, lower values in nondisease range in blood pressure, glycosylated hemoglobin A1c, triglyceride, and uric acid were independently associated with the slow progression of arterial stiffness. For body mass index and low-density lipoprotein cholesterol, no clear associations with the progression of arterial stiffness were observed. Conclusions: The present prospective study provided more robust epidemiological evidence for the heterogeneity of the significance of contribution of lifelong status of each CVRF to the slow and fast rate of progression of arterial stiffness. These findings suggest the important need to examine, in further studies, the effects of global early interventions to control the levels of the culprit CVRFs, even from middle age, not only to prevent a fast progression of the arterial stiffness but also to maintain a relatively slow progression of arterial stiffness.

31 July 2023 in Cardiovascular Diabetology
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Journal Article
Open access
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ATAtsushi Tanaka
Atsushi Tanaka
HSHirotaka Shibata
Hirotaka Shibata
TITakumi Imai
Takumi Imai
HYHisako Yoshida
Hisako Yoshida
MMMotoaki Miyazono
Motoaki Miyazono
TIthe FIVE-STAR trial investigators
the FIVE-STAR trial investigators
Background: The overactivation of mineralocorticoid receptor (MR) plays a key pathological role in the progression of cardiovascular and renal diseases by promoting pro-inflammatory and pro-fibrotic signaling. Recently, it has been found that finerenone, a novel nonsteroidal selective MR antagonist, can robustly improve cardiorenal outcomes in patients with type 2 diabetes (T2D) and a wide spectrum of chronic kidney disease (CKD). However, the mechanisms underlying the cardiorenal benefits of finerenone are poorly understood. Further, whether the clinical benefits are mediated by an improvement in vascular stiffness is not confirmed. Therefore, the current study aims to evaluate the effects of finerenone on vascular stiffness as assessed using cardio ankle vascular index (CAVI) and relevant cardiorenal biomarkers in patients with T2D and CKD. Methods: The Effects of Finerenone on Vascular Stiffness and Cardiorenal Biomarkers in Type 2 Diabetes and Chronic Kidney Disease (FIVE-STAR) is an ongoing, investigator-initiated, multicenter, prospective, placebo-controlled, double-blind, randomized clinical trial in Japan. Its target sample size is 100 subjects. Recruitment will be performed from September 2023 to July 2024. After obtaining informed consent, eligible participants with T2D and CKD (25 mL/min/1.73 m2 ≤ estimated glomerular filtration ratio [eGFR] < 90 mL/min/1.73 m2 and 30 mg/g Cr ≤ urinary albumin-to-creatinine ratio [UACR] < 3500 mg/g Cr) will be equally randomized to receive 24-week treatment with either finerenone (starting dose at 10 mg once daily in participants with a baseline eGFR < 60 mL/min/1.73 m2 or at 20 mg once daily in those with a baseline eGFR ≥ 60 mL/min/1.73 m2) or dose-matched placebo. The primary endpoint is the change from baseline in CAVI at 24 weeks. The secondary endpoints are changes from baseline in UACR at 12 and 24 weeks and relevant serum and urinary biomarkers at 24 weeks. As an exploratory endpoint, proteomic analysis using the Olink® Target 96 panels will be also performed. Discussion: FIVE-STAR is the first trial evaluating the therapeutic impact of finerenone on vascular stiffness and relevant cardiorenal biomarkers in patients with T2D and CKD. This study will provide mechanistic insights on the clinical benefits of finerenone based on recent cardiovascular and renal outcome trials. Trial registration Unique Trial Number, NCT05887817 (https://clinicaltrials.gov/ct2/show/NCT05887817) and jRCTs021230011 (https://jrct.niph.go.jp/latest-detail/jRCTs021230011).

7 July 2023 in Diabetology & Metabolic Syndrome
Verified
Journal Article
Open access
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ATAtsushi Tanaka
Atsushi Tanaka
TITakumi Imai
Takumi Imai
STShigeru Toyoda
Shigeru Toyoda
KSKazuhiro Sugimoto
Kazuhiro Sugimoto
RYRuka Yoshida
Ruka Yoshida
TIthe PROTECT Investigators
the PROTECT Investigators
Backgrounds/Aim: Recent studies have shown that the addition of sodium-glucose co-transporter 2 (SGLT2) inhibitors gradually reduces the estimated fluid volume parameters in a broad range of patient populations, suggesting that this mediates the clinical benefits of SGLT2 inhibitors in preventing heart failure. Here, we sought to examine the long-term (24 months) effect of the SGLT2 inhibitor ipragliflozin on the estimated fluid volume parameters in patients with type 2 diabetes mellitus (T2DM).Methods: In this prespecified sub-analysis of the PROTECT (Prevention of Atherosclerosis by SGLT2 Inhibitor: Multicenter, Randomized Controlled Study) trial, which was an investigator-initiated, multicenter, prospective, randomized, open-label, clinical trial primarily designed to evaluate the effect of ipragliflozin treatment administered for 24 months on carotid atherosclerosis in patients with T2DM, we evaluated serial changes in estimated plasma volume (ePV, %) calculated using the Straus formula and estimated extracellular volume (eEV, mL) calculated by the body surface area by 24 months following the initiation of 50-mg ipragliflozin once daily and compared them with those following standard care for T2DM (non-SGLT2 inhibitor use).Results: This sub-analysis included 464 patients (ipragliflozin,n = 232; control,n = 232), a full analysis set of the PROTECT trial. In an analysis using mixed-effects models for repeated measures, relative to the control group, ipragliflozin significantly reduced ePV by − 10.29% (95% confidence interval [CI] − 12.47% to − 8.11%;P < 0.001) at 12 months and − 10.76% (95% CI − 12.86% to − 8.67%;P < 0.001) at 24 months. Additionally, ipragliflozin significantly reduced eEV by − 190.44 mL (95% CI − 249.09 to − 131.79 mL;P < 0.001) at 12 months and − 176.90 mL (95% CI − 233.36 to − 120.44 mL;P < 0.001) at 24 months. The effects of ipragliflozin on these parameters over 24 months were mostly consistent across various patient clinical characteristics.Conclusions: This prespecified sub-analysis from the PROTECT trial demonstrated that ipragliflozin treatment, compared with the standard care for T2DM, reduced two types of estimated fluid volume parameters in patients with T2DM, and the effect was maintained for 24 months. Our findings suggest that SGLT2 inhibitor treatment regulates clinical parameters incorporated into the calculating formulas analyzed and consequently fluid volume status for the long-term, and this may be at least partly associated with clinical benefits from chronic use of SGLT2 inhibitors.Trial registrationJapan Registry of Clinical Trials, ID jRCT1071220089

27 November 2023 in Vaccines
Verified
Journal Article
Open access
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TKTakenao Koseki
Takenao Koseki
MTMayumi Teramachi
Mayumi Teramachi
MKMinako Koga
Minako Koga
MKMinoru S. H. Ko
Minoru S. H. Ko
TATomokazu Amano
Tomokazu Amano
YDYohei Doi
Yohei Doi
MRNA vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have played a key role in reducing morbidity and mortality from coronavirus disease 2019 (COVID-19). We conducted a double-blind, placebo-controlled phase I/II trial to evaluate the safety, tolerability, and immunogenicity of EXG-5003, a two-dose, controllable self-replicating RNA vaccine against SARS-CoV-2. EXG-5003 encodes the receptor binding domain (RBD) of SARS-CoV-2 and was administered intradermally without lipid nanoparticles (LNPs). The participants were followed for 12 months. Forty healthy participants were enrolled in Cohort 1 (5 µg per dose, n = 16; placebo, n = 4) and Cohort 2 (25 µg per dose, n = 16; placebo, n = 4). No safety concerns were observed with EXG-5003 administration. SARS-CoV-2 RBD antibody titers and neutralizing antibody titers were not elevated in either cohort. Elicitation of antigen-specific cellular immunity was observed in the EXG-5003 recipients in Cohort 2. At the 12-month follow-up, participants who had received an approved mRNA vaccine (BNT162b2 or mRNA-1273) >1 month after receiving the second dose of EXG-5003 showed higher cellular responses compared with equivalently vaccinated participants in the placebo group. The findings suggest a priming effect of EXG-5003 on the long-term cellular immunity of approved SARS-CoV-2 mRNA vaccines.