Details of a Researcher - WAKI Hironori

WAKI Hironori

写真a

Affiliation	Graduate School of Medicine Doctorial Course in Medicine Bioregulatory Medicine Department of Metabolism and Endocrinology
Mail Address

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Research Interests 【 display / non-display 】

遺伝子
脂肪細胞
内分泌
代謝
糖尿病

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Graduating School 【 display / non-display 】

　

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1997.03

The University of Tokyo Faculty of Medicine Graduated

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Graduate School 【 display / non-display 】

　

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2003.03

The University of Tokyo Graduate School, Division of Medicine Doctor's Course Completed

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Campus Career 【 display / non-display 】

2021.06

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Now

Akita University Graduate School of Medicine Doctorial Course in Medicine Bioregulatory Medicine Department of Metabolism and Endocrinology Professor

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External Career 【 display / non-display 】

2019.09

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2021.05

Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo Associate Professor
2018.11

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2019.08

Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo Lecturer
2016.09

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2018.10

Department of Molecular Sciences on Diabetes, Graduate School of Medicine, the University of Tokyo Project Associate Professor

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Research Areas 【 display / non-display 】

Life Science / Molecular biology / Molecular biology
Life Science / Nutrition science and health science
Life Science / Cell biology / Cellular biology
Life Science / Genetics / Genomics
Life Science / Metabolism and endocrinology / Diabetes and Metabolic Diseases

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Research Achievements 【 display / non-display 】

◆Original paper【 display / non-display 】

Digital Intervention Increasing Sleep Duration Among People With Type 2 Diabetes: Pilot Randomized Controlled Trial.

Ryohei Nakada, Daniel R Lane, Shuya Iwata, Akihiro Isogawa, Masao Toyoda, Hideaki Sawaki, Takashi Murata, Shinichi Kajino, Hironori Waki, Shunsuke Kato, Tomoya Kawaguchi, Yushi Hirota, Shuichiro Saito, Seiji Nishikage, Kazuki Yokota, Yuya Tsurutani, Atsuhito Tone, Kengo Miyoshi, Toshimasa Yamauchi, Masaomi Nangaku, Kayo Waki

Journal of diabetes science and technology 19322968261445108 - 19322968261445108 2026.05 [Refereed]

Research paper (journal)

INTRODUCTION AND OBJECTIVE: Short sleep duration is associated with worse hemoglobin A1c (HbA1c), and treatment guidelines recommend sufficient sleep duration. However, it is unclear whether extending sleep duration of short-sleeping people with type 2 diabetes causes improved HbA1c. We aimed to assess the effect on HbA1c of increasing sleep duration. METHODS: We developed a personalized digital intervention based on the theory of planned behavior and conducted a single-blind, two-arm randomized controlled trial with 70 short-sleeping (≤6 hours) people with type 2 diabetes in Japan. Both arms measured sleep duration using an actigraph and a sleep diary. The intervention group received bedtime advancement support, including achievable bedtime goal setting and feedback. The primary outcome was between-arm difference in HbA1c change after 12 weeks. RESULTS: The baseline average sleep duration and HbA1c were 5.96 ± 1.26 (hours) and 8.30 ± 0.91 (%) in the intervention group, and 5.94 ± 0.96 (hours) and 8.09 ± 0.51 (%) in the control group, respectively. Sleep duration improved with statistical significance (between-arm difference in change: 32.8 minutes, P = .0042). However, HbA1c did not reduce significantly (between-arm difference in change: -0.11%, P = .51), and increases in sleep duration were not significantly associated with HbA1c reduction (P = .69). CONCLUSION: In this randomized trial, an average sleep extension of approximately 30 minutes over 12 weeks did not result in a significant improvement in HbA1c among short-sleeping adults with type 2 diabetes. Further studies with larger sample sizes and greater sleep extension are warranted.

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Assay-Specific Diagnostic Thresholds for Adrenal Insufficiency: A Retrospective Comparison of Monoclonal Cortisol Measurements Using Roche Elecsys Cortisol II and Tosoh AIA-CL2400

Shunsuke Kato, Hana Akanuma, Mitsuhiko Nara, Takehiro Sato, Tsukasa Morii, Hiroki Fujita, Hironori Waki

Cureus 18 ( 4 ) e107059 2026.04 [Refereed]

Research paper (journal)

Decoding the Adipocyte Epigenome: Differentiation, Metabolic Memory, and Obesity.

Shunsuke Kato, Hironori Waki

Journal of obesity & metabolic syndrome 34 ( 4 ) 378 - 393 2025.10 [Refereed] [Invited]

Research paper (journal)

Adipocytes play a central role in energy balance by integrating lipid storage, thermogenesis, and endocrine regulation. Their diversity-comprising white, brown, and beige adipocytes-emerges through tightly coordinated transcriptional and epigenetic programs. In addition to transcription factors, epigenetic mechanisms such as DNA methylation and histone modifications mediated by acetyltransferases, methyltransferases, and demethylases shape the chromatin states that govern adipocyte differentiation and function. The concept of metabolic memory refers to the long-lasting imprint that environmental and nutritional cues make on cells and tissues; it can facilitate rapid adaptation to subsequent challenges but also predispose organisms to metabolic dysfunction and related complications. Recent technological advances have revealed that cold exposure and obesity leave epigenomic marks on adipocytes, providing mechanistic insights into how metabolic memory is encoded. This review highlights the fundamental principles of the adipose tissue epigenome, the regulation of adipocyte identity, and how epigenomic memory links environmental history to long-term metabolic health.

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Impact of Tirzepatide on diet-related quality of life and treatment satisfaction in people with type 2 diabetes mellitus: a retrospective cross-sectional study.

Shunsuke Kato, Ayaka Kokita, Hana Akanuma, Shogo Iwamura, Yuya Takahashi, Ryota Kusumi, Sakiko Abe, Kana Sasaki, Hitomi Otomo, Sayaka Ando, Mitsuhiko Nara, Aiko Nara, Takenobu Tadika, Tatsunori Shimizu, Takehiro Sato, Tsukasa Morii, Hiroki Fujita, Daisuke Matsuda, Hironori Waki

Diabetes research and clinical practice 229 112913 - 112913 2025.09 [Refereed]

Research paper (journal)

AIMS: To explore how Tirzepatide (TZP) treatment influences diet-related quality of life (QoL) and thus treatment satisfaction. METHODS: This retrospective observational study analyzed 95 people with type 2 diabetes mellitus treated with TZP. We evaluated measurements before and after TZP treatment for clinical parameters (including BMI and HbA1c) and, via validated questionnaires, patient-reported treatment satisfaction and diet-related QoL (including the Diabetes Diet-Related Quality of Life-Revised 9 (DDRQOL-R-9)). We used Spearman correlations and multiple regression analyses to identify predictors of treatment satisfaction. RESULTS: TZP treatment led to significant reduction of median (7.4 % to 6.4 %) and body weight (77.2 kg to 70.6 kg). Median diet-related QoL, specifically the "perceived merits of dietary therapy", increased from 58.3 [IQR 50.0, 75.0] to 67.7 [50.0, 83.3] (p < 0.01). Multiple regression analysis identified changes in BMI (standardized β =  - 0.21, p = 0.030) and changes in diet-related QoL "perceived merits of dietary therapy" (β = 0.23, p = 0.019) as independent predictors of DTSQs scores post-TZP treatment. CONCLUSION: Despite TZP's appetite-suppressing effects, diet-related QoL, particularly the "perceived merits of dietary therapy", significantly increased with treatment, serving as an independent and substantial contributor to patient satisfaction, comparable to the impact of body weight reduction. (195 words).

DOI PubMed

Efficacy of a Personalized Mobile Health Intervention (BedTime) to Increase Sleep Duration Among Short-Sleeping Patients With Type 2 Diabetes: Protocol for a Pilot Randomized Controlled Trial.

Yuki Ban, Kayo Waki, Ryohei Nakada, Akihiro Isogawa, Kengo Miyoshi, Hironori Waki, Shunsuke Kato, Hideaki Sawaki, Takashi Murata, Yushi Hirota, Shuichiro Saito, Seiji Nishikage, Atsuhito Tone, Mayumi Seno, Masao Toyoda, Shinichi Kajino, Kazuki Yokota, Yuya Tsurutani, Toshimasa Yamauchi, Masaomi Nangaku, Kazuhiko Ohe

JMIR research protocols 14 e64023 2025.04

Research paper (journal)

BACKGROUND: A strong association exists between sleep duration and glycemic control in patients with type 2 diabetes (T2D), yet convincing evidence of a causal link remains lacking. Improving sleep is increasingly emphasized in clinical T2D treatment guidance, highlighting the need for effective, scalable sleep interventions that can affordably serve large populations through mobile health (mHealth). OBJECTIVE: This study aims to pilot an intervention that extends sleep duration by modifying bedtime behavior, assessing its efficacy among short-sleeping (≤6 hours per night) patients with T2D, and establishing robust evidence that extending sleep improves glycemic control. METHODS: This randomized, single-blinded, multicenter study targets 70 patients with T2D from 9 institutions in Japan over a 12-week intervention period. The sleep extension intervention, BedTime, is developed using the Theory of Planned Behavior (TPB) and focuses on TPB's constructs of perceived and actual behavioral control (ABC). The pilot intervention combines wearable actigraphy devices with SMS text messaging managed by human operators. Both the intervention and control groups will use an actigraphy device to record bedtime, sleep duration, and step count, while time in bed (TIB) will be assessed via sleep diaries. In addition, the intervention group will receive weekly bedtime goals, daily feedback on their bedtime performance relative to those goals, identify personal barriers to an earlier bedtime, and select strategies to overcome these barriers. The 12-week intervention period will be followed by a 12-week observational period to assess the sustainability of the intervention's effects. The primary outcome is the between-group difference in the change in hemoglobin A1c (HbA1c) at 12 weeks. Secondary outcomes include other health measures, sleep metrics (bedtime, TIB, sleep duration, total sleep time, and sleep quality), behavioral changes, and assessments of the intervention's usability. The trial commenced on February 8, 2024, and is expected to conclude in February 2025. RESULTS: Patient recruitment ended on August 29, 2024, with 70 participants enrolled. The intervention period concluded on December 6, 2024, and the observation period ended on February 26, 2025, with 70 participants completing the observation period. The data analysis is currently underway, and results are expected to be published in July 2025. CONCLUSIONS: This trial will provide important evidence on the causal link between increased sleep duration and improved glycemic control in short-sleeping patients with T2D. It will also evaluate the efficacy of our bedtime behavior change intervention in extending sleep duration, initially piloted with human operators, with the goal of future implementation via an mHealth smartphone app. If proven effective, this intervention could be a key step toward integrating sleep-focused mHealth into the standard treatment for patients with T2D in Japan. TRIAL REGISTRATION: Japan Registry of Clinical Trials jRCT1030230650; https://jrct.niph.go.jp/latest-detail/jRCT1030230650. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/64023.

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