KEIO RESEARCHERS INFORMATION SYSTEM

Academic Degrees 【 Display / hide 】

Academic Degrees 【 Display / hide 】

• 博士(獣医保健看護学), Nippon Veterinary and Life Science University, 2024.03

Papers 【 Display / hide 】

Papers 【 Display / hide 】

• Time series analysis of ex-vivo ischemia-reperfused heart using Q-space imaging

  Ichihara G., Hata J., Nakashima D., Daigo K., Sugai K., Iwasawa Y., Sano M., Nakamura M., Okano H., Sato K., Katsumata Y.

  Scientific Reports 15 ( 1 )  2025.12

  　View Summary

  In the evaluation of myocardial infarction, cardiac MRI remains problematic in terms of sensitivity and quantitativeness. Thus, we sought to delineate pathological microstructural alterations across temporal phases subsequent to myocardial ischemia–reperfusion (IR) injury utilizing q-space imaging (QSI), an advanced diffusion imaging methodology proficient in assessing the non-Gaussian diffusion patterns of molecules. Rats were subjected to IR injury, and infarct was evaluated at 2, 7, and 30 days via histopathological staining and MRI using a 9.4‐Tesla system. QSI was performed with gadolinium-enhanced T1-weighted imaging (T1WI) for comparative assessment. Correlation coefficients among images were computed at each level of the left ventricular short-axis cross-section to juxtapose the infarct dimensions and morphology. Axial diffusivity of the kurtosis maps at 2, 7, and 30 days revealed substantial correlations with the hyperintense areas noted on T1WI (R² = 0.885, 0.947, and 0.929, respectively). Furthermore, a strong correlation was noted with the transmural extent of infarction. Even in the absence of gadolinium contrast, the high-intensity regions delineated by QSI were concordant with the extent of pathological infarction (R² = 0.977). These findings highlight the capability of QSI in identifying pathological changes at the infarct site, independent of gadolinium contrast media and irrespective of the temporal phase subsequent to the IR onset.

  • Access to Document (DOI)

• A Pilot Study on the Effects of Sweet Potato Petiole and Leaf Powder on Gut Microbiota and Aging-Related Biomarkers in an Aged Microminipig Model

  Sugai K., Miyamoto Y., Sato T., Hakamata Y., Murakoshi T., Kobayashi S., Iwamoto S., Kobayashi E.

  Metabolites 15 ( 11 )  2025.11

  　View Summary

  Background/Objectives: Although many healthy foods are used for elderly humans, there are no suitable animal models to test them. We reared microminipigs (MMPs) for over 10 years, establishing aged MMP models. Using this aged preclinical model, we evaluated the effects of a polyphenol-rich diet without sacrificing the animals. Methods: A polyphenol-rich diet containing sweet potato petioles and leaves was administered to the aged MMPs daily for one month. Changes in fecal microbiota and aging-related cells in the peripheral blood before and after administration were assessed. Results: Administration of a diet containing sweet potato petiole and leaf resulted in increased abundance of the genera Muribaculaceae, Oscillibacter, and Desulfovibrio and a decreased abundance of the genus UCG-002 within the family Oscillospiraceae. Prediction of metabolic enzyme activity from microbiota composition identified 77 enzymes significantly altered after administration. KEGG Mapper analysis of these enzymes revealed their involvement in 27 pathways. Flow cytometry analysis of peripheral blood revealed no significant differences in the proportion of ß-galactosidase-positive cells in either group. In contrast, a significant increase in the number of Ki-67-positive cells was observed in some individuals in the treatment group. However, no significant differences in Ki-67 expression were detected after stimulation with anti-CD3/CD28 antibodies. Conclusions: We established an aged MMP model to evaluate the efficacy and safety of drugs and health foods in elderly humans. Using this model, sweet potato petioles and leaves were shown to have potential as candidate materials for future health food research.

  • Access to Document (DOI)

• Positive effects of single-nanosized oxygen nanobubble water on exercise tolerance: A randomized crossover trial

  Muramoto Y., Ishida N., Minaguchi E., Sugai K., Daigo K., Iwasawa Y., Ichihara G., Nagashima K., Sato Y., Sato K., Katsumata Y.

  Current Research in Physiology 8 2025.01

  　View Summary

  The effect of single-nanosized oxygen nanobubble water (NBO<inf>2</inf>W), an oxygen-enriched beverage, on exercise performance remains unclear. This double-blind, randomized, placebo-controlled crossover trial investigated whether NBO<inf>2</inf>W intake influences lactate threshold (LT), a key indicator of aerobic exercise performance. The participants (n = 20; age, 47.4 ± 5.0 years; female, 12) consumed either NBO<inf>2</inf>W or placebo water (PW) immediately followed by an incremental exercise test on an ergometer for symptom-limited exhaustion. During the test, the heart rate, respiratory gas analysis (VO<inf>2</inf> and VCO<inf>2</inf>), tissue oxygen index (TOI), and blood lactate level were continuously monitored. The first administered beverage was randomly selected, with both participants and investigators blinded to the beverages. A washout period of minimum seven days was implemented between the two tests. The mean peak VO<inf>2</inf> was 26.13 ± 5.05 mL/min/kg. Eighteen (90 %) participants exercised less than four times per week, indicating limited exercise habits. The average washout period was 9.7 ± 5.0 days. The work rate (WR) at LT was significantly higher after NBO<inf>2</inf>W intake than after PW intake (mean difference = 3.33 W, p = 0.03). The WR was not significantly different at peak VO<inf>2</inf> or at the onset of blood lactate accumulation. Furthermore, NBO<inf>2</inf>W intake significantly increased the lactate levels 5 min post-exercise (mean difference = 0.88, p = 0.01) and decreased the TOI (mean difference = −3.8, p = 0.01). Short-term NBO<inf>2</inf>W consumption in three doses, including that on the day before exercise, did not affect the peak exercise capacity, but improved the WR at LT.

  • Access to Document (DOI)

• Angiotensin-converting gene and hypoxic exercise tolerance: A randomized crossover trial

  Muramoto Y., Momoi M., Nakashima D., Omae K., Sugai K., Daigo K., Iwasawa Y., Ichihara G., Okawara H., Sawada T., Kinoda A., Yamada Y., Kimura T., Sato K., Katsumata Y.

  International Journal of Sports Medicine 46 ( 4 ) 246 - 254 2025

  ISSN  01724622

  　View Summary

  Hypoxic training enhances endurance sports tolerance. However, individual responses vary due to physiological differences. This study investigated the relationship between genetic factors and exercise tolerance in hypoxic conditions. This randomized crossover study included 22 male university students (age 20.8±1.3 years, peak oxygen uptake 54.5±6.5 mL/min/kg). Incremental load tests were conducted to assess the symptomatic limit on separate days under normoxic and hypoxic conditions (oxygen concentration 15.4±0.8%) using an ergometer. The initial test environment was randomized. The peak oxygen uptake and blood lactate were monitored every minute, and Δ peak oxygen uptake (peak oxygen uptake under hypoxia - peak oxygen uptake under normoxia) was calculated. Sixteen genotypes linked to exercise tolerance (such as angiotensin-converting enzyme [ACE]) were examined. Peak oxygen uptake significantly decreased under hypoxia (p<0.01). Δ peak oxygen uptake varied among individuals (minimum: 0.7 and maximum: - 18.9). Among analyzed genetic polymorphisms, ACE-II genotypes showed significantly greater Δ peak oxygen uptake than ACE-ID/ACE-DD genotypes (p=0.02). ACE-II genotypes exhibited lower blood lactate elevation at peak exercise in normoxic (p=0.01) and hypoxic (p=0.03) conditions. Participants with the ACE-II genotype had lower lactate concentrations and greater reductions in peak oxygen uptake under hypoxic conditions. Optimizing hypoxic training requires individualized programs incorporating genetic analysis.

  • Access to Document (DOI)

• Inhibition of Scarb1 on Endothelial Cells Attenuates Pressure Overload-induced Heart Failure Progression

  Katsuki T., Kusumoto D., Akiba Y., Kimura M., Komuro J., Nakamura T., Hashimoto H., Kouka T., Sugai K., Katsumata Y., Miyasaka M., Suzuki Y., Kuramoto J., Kubota Y., Fukuda K., Yuasa S., Ieda M.

  Jacc Basic to Translational Science 10 ( 10 )  2025

  ISSN  2452302X

  　View Summary

  Inappropriate endothelial cell (EC) interactions contribute to heart failure; however, their precise mechanisms remain poorly understood. This study investigated EC-fibroblast interactions mediated by Scarb1 using single-cell RNA-sequencing analysis in a mouse heart failure model. ECs exhibited inflammatory and fibrotic gene expression, with Scarb1-mediated fibroblast-EC interactions driving disease progression. EC-specific Scarb1 knockout and systemic SCARB1 inhibition attenuated heart failure progression. In vitro and spatial omics analyses confirmed the role of SCARB1 in ECs and cell-cell interaction during heart failure progression. These findings highlight SCARB1 as a promising therapeutic target for EC-focused interventions.

  • Access to Document (DOI)

display all >>

Presentations 【 Display / hide 】

Presentations 【 Display / hide 】

• スナネズミの血液凝固不全の原因探索

  袴田陽二, 工藤香織, 小田朝陽, 鎌田由依, 菅井和久, 藤澤正彦

  第168回日本獣医学会学術集会, 

  2025.09

• 水素ガスによるアトピー性皮膚炎根治への挑戦

  舩川桜, 菅井和久, 田原海, 伊東可寛, 勝俣良紀

  第168回日本獣医学会学術集会, 

  2025.09

• アセトアミノフェン誘発性肝炎モデルにおけるグルタミナーゼ阻害薬の効果の検証

  藤澤正彦, 小田朝陽, 菅井和久, 袴田陽二

  第168回日本獣医学会学術集会, 

  2025.09

• CKD Models in Rats Created by Microsurgical Technique

  Sugai K, Fujisawa M, Katsumata Y, Kobayashi E, Hakamata Y.

  The 17th Congress of The International Society for Experimental Microsurgery, 

  2025.05

• サツマイモ葉柄部の一過性脳虚血スナネズミに対する神経細胞保護効果

  前田友香, 小田朝陽, 菅井和久, 藤澤正彦, 袴田陽二.

  第72回日本実験動物学会総会, 

  2025.05

display all >>