Shigeki Aoki

Dr. Shigeki Aoki

orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

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

Representative Publications

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10 December 2019 in Scientific Reports
Verified
Journal Article
Open access
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RSReika Shiratori
Reika Shiratori
KFKenta Furuichi
Kenta Furuichi
MYMasashi Yamaguchi
Masashi Yamaguchi
NMNatsumi Miyazaki
Natsumi Miyazaki
HAHaruna Aoki
Haruna Aoki
SAShigeki Aoki
Shigeki Aoki
Most cancer cells rely on glycolysis to generate ATP, even when oxygen is available. However, merely inhibiting the glycolysis is insufficient for the eradication of cancer cells. One main reason for this is that cancer cells have the potential to adapt their metabolism to their environmental conditions. In this study, we investigated how cancer cells modify their intracellular metabolism when glycolysis is suppressed, using PANC-1 pancreatic cancer cells and two other solid tumor cell lines, A549 and HeLa. Our study revealed that glycolytically suppressed cells upregulated mitochondrial function and relied on oxidative phosphorylation (OXPHOS) to obtain the ATP necessary for their survival. Dynamic changes in intracellular metabolic profiles were also observed, reflected by the reduced levels of TCA cycle intermediates and elevated levels of most amino acids. Glutamine and glutamate were important for this metabolic reprogramming, as these were largely consumed by influx into the TCA cycle when the glycolytic pathway was suppressed. During the reprogramming process, activated autophagy was involved in modulating mitochondrial function. We conclude that upon glycolytic suppression in multiple types of tumor cells, intracellular energy metabolism is reprogrammed toward mitochondrial OXPHOS in an autophagy-dependent manner to ensure cellular survival.

8 December 2016 in American Journal of Neuroradiology
Verified
Journal Article
Open access
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AHAkifumi Hagiwara
Akifumi Hagiwara
MHM. Hori
M. Hori
KYKazumasa Yokoyama
Kazumasa Yokoyama
MTM.Y. Takemura
M.Y. Takemura
CAChristina Andica
Christina Andica
SAShigeki Aoki
Shigeki Aoki
BACKGROUND AND PURPOSE: Synthetic MR imaging enables the creation of various contrast-weighted images including double inversion recovery and phase-sensitive inversion recovery from a single MR imaging quantification scan. Here, we assessed whether synthetic MR imaging is suitable for detecting MS plaques. MATERIALS AND METHODS: Quantitative and conventional MR imaging data on 12 patients with MS were retrospectively analyzed. Synthetic T2-weighted, FLAIR, double inversion recovery, and phase-sensitive inversion recovery images were produced after quantification of T1 and T2 values and proton density. Double inversion recovery images were optimized for each patient by adjusting the TI. The number of visible plaques was determined by a radiologist for a set of these 4 types of synthetic MR images and a set of conventional T1-weighted inversion recovery, T2-weighted, and FLAIR images. Conventional 3D double inversion recovery and other available images were used as the criterion standard. The total acquisition time of synthetic MR imaging was 7 minutes 12 seconds and that of conventional MR imaging was 6 minutes 29 seconds The lesion-to-WM contrast and lesion-to-WM contrast-to-noise ratio were calculated and compared between synthetic and conventional double inversion recovery images. RESULTS: The total plaques detected by synthetic and conventional MR images were 157 and 139, respectively (P = .014). The lesion-to-WM contrast and contrast-to-noise ratio on synthetic double inversion recovery images were superior to those on conventional double inversion recovery images (P = .001 and < 0.001, respectively). CONCLUSIONS: Synthetic MR imaging enabled detection of more MS plaques than conventional MR imaging in a comparable acquisition time. The contrast for MS plaques on synthetic double inversion recovery images was better than on conventional double inversion recovery images.

10 January 2019 in American Journal of Neuroradiology
Verified
Journal Article
Open access
PDF file
AHAkifumi Hagiwara
Akifumi Hagiwara
YOY. Otsuka
Y. Otsuka
MHM. Hori
M. Hori
YTYasuhiko Tachibana
Yasuhiko Tachibana
KYKazumasa Yokoyama
Kazumasa Yokoyama
SAShigeki Aoki
Shigeki Aoki
BACKGROUND AND PURPOSE: Synthetic FLAIR images are of lower quality than conventional FLAIR images. Here, we aimed to improve the synthetic FLAIR image quality using deep learning with pixel-by-pixel translation through conditional generative adversarial network training. MATERIALS AND METHODS: Forty patients with MS were prospectively included and scanned (3T) to acquire synthetic MR imaging and conventional FLAIR images. Synthetic FLAIR images were created with the SyMRI software. Acquired data were divided into 30 training and 10 test datasets. A conditional generative adversarial network was trained to generate improved FLAIR images from raw synthetic MR imaging data using conventional FLAIR images as targets. The peak signal-to-noise ratio, normalized root mean square error, and the Dice index of MS lesion maps were calculated for synthetic and deep learning FLAIR images against conventional FLAIR images, respectively. Lesion conspicuity and the existence of artifacts were visually assessed. RESULTS: The peak signal-to-noise ratio and normalized root mean square error were significantly higher and lower, respectively, in generated-versus-synthetic FLAIR images in aggregate intracranial tissues and all tissue segments (all P < .001). The Dice index of lesion maps and visual lesion conspicuity were comparable between generated and synthetic FLAIR images (P = 1 and .59, respectively). Generated FLAIR images showed fewer granular artifacts (P = .003) and swelling artifacts (in all cases) than synthetic FLAIR images. CONCLUSIONS: Using deep learning, we improved the synthetic FLAIR image quality by generating FLAIR images that have contrast closer to that of conventional FLAIR images and fewer granular and swelling artifacts, while preserving the lesion contrast.

27 October 2016 in American Journal of Neuroradiology
Verified
Journal Article
Open access
PDF file
AHAkifumi Hagiwara
Akifumi Hagiwara
MHM. Hori
M. Hori
KYKazumasa Yokoyama
Kazumasa Yokoyama
MTM.Y. Takemura
M.Y. Takemura
CAChristina Andica
Christina Andica
SAShigeki Aoki
Shigeki Aoki
BACKGROUND AND PURPOSE: T1 and T2 values and proton density can now be quantified on the basis of a single MR acquisition. The myelin and edema in a voxel can also be estimated from these values. The purpose of this study was to evaluate a multiparametric quantitative MR imaging model that assesses myelin and edema for characterizing plaques, periplaque white matter, and normal-appearing white matter in patients with MS. MATERIALS AND METHODS: We examined 3T quantitative MR imaging data from 21 patients with MS. The myelin partial volume, excess parenchymal water partial volume, the inverse of T1 and transverse T2 relaxation times (R1, R2), and proton density were compared among plaques, periplaque white matter, and normal-appearing white matter. RESULTS: All metrics differed significantly across the 3 groups (P < .001). Those in plaques differed most from those in normal-appearing white matter. The percentage changes of the metrics in plaques and periplaque white matter relative to normal-appearing white matter were significantly more different from zero for myelin partial volume (mean, −61.59 ± 20.28% [plaque relative to normal-appearing white matter], and mean, −10.51 ± 11.41% [periplaque white matter relative to normal-appearing white matter]), and excess parenchymal water partial volume (13.82 × 103 ± 49.47 × 103% and 51.33 × 102 ± 155.31 × 102%) than for R1 (−35.23 ± 13.93% and −6.08 ± 8.66%), R2 (−21.06 ± 11.39% and −4.79 ± 6.79%), and proton density (23.37 ± 10.30% and 3.37 ± 4.24%). CONCLUSIONS: Multiparametric quantitative MR imaging captures white matter damage in MS. Myelin partial volume and excess parenchymal water partial volume are more sensitive to the MS disease process than R1, R2, and proton density.

14 August 2024 in British Journal of Dermatology
Verified
Journal Article
Open access
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NHNatsumi Hama
Natsumi Hama
SAShigeki Aoki
Shigeki Aoki
CCChun-Bing Chen
Chun-Bing Chen
AHAkito Hasegawa
Akito Hasegawa
YOYouichi Ogawa
Youichi Ogawa
RARiichiro Abe
Riichiro Abe
Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) represent a severe spectrum of rare mucocutaneous reactions that are primarily drug-induced and characterized by significant morbidity and mortality. These conditions manifest in extensive skin detachment, distinguishing them from other generalized skin eruptions. The rarity and severity of SJS/TEN underscore the importance of accurate diagnostic criteria and effective treatments, which are currently lacking consensus. This review proposes new diagnostic criteria to improve specificity and global applicability. Recent advances in understanding the immunopathogenesis of SJS/TEN are explored, emphasizing the role of drug-specific T-cell responses and human leucocyte antigen polymorphisms in disease onset. The review also addresses current therapeutic approaches, including controversies surrounding the use of immunosuppressive agents and the emerging role of tumour necrosis factor-α inhibitors. Novel therapeutic strategies targeting specific pathogenic mechanisms, such as necroptosis and specific immune cell pathways, are discussed. Furthermore, the development of new drugs based on these insights, including targeted monoclonal antibodies and inhibitors, are examined. The review concludes by advocating for more robust and coordinated efforts across multidisciplinary medical fields to develop effective treatments and diagnostic tools for SJS/TEN, with the aim of improving patient outcomes and understanding the disease and its mechanisms.

25 September 2018 in Oncotarget
Verified
Journal Article
Open access
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KAKaori Aoto
Kaori Aoto
KIKousei Ito
Kousei Ito
SAShigeki Aoki
Shigeki Aoki
Complex formation between platelet-derived growth factor receptor and transforming growth factor receptor regulates the differentiation of mesenchymal stem cells into cancer-associated fibroblasts Complex formation between platelet-derived growth factor receptor β and transforming growth factor β receptor regulates the differentiation of mesenchymal stem cells into cancer-associated fibroblasts