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IWATA Sachiko

    Graduate School of Medical Sciences Core Laboratory　Assistant Professor
Last Updated :2026/08/29

Researcher Information

J-Global ID

Research Interests

  • development   circadian rhythm   hypoxia-ischaemia   brain injury   newborn infant   

Research Areas

  • Humanities & social sciences / Early childhood education and childcare / Brain injury, environment and development of infant

Published Papers

MISC

Research Grants & Projects

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2026/04 -2031/03 
    Author : 岩田 欧介; 中川 志信; 岡村 尚昌; 永井 幸代; 岩田 幸子; 坂田 昌嗣; 横山 清子; 荒木 由布子; 諸隈 誠一
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2024/04 -2029/03 
    Author : 岩田 幸子; 津田 兼之介; 杉浦 真弓; 岩田 欧介; 横井 暁子; 横山 清子; 尾崎 康彦; 荒木 由布子; 古川 壽亮
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2024/04 -2027/03 
    Author : 横井 暁子; 井上 貴子; 加藤 丈典; 岩田 幸子
  • 日本学術振興会：科学研究費助成事業
    Date (from‐to) : 2024/04 -2027/03 
    Author : 加藤 晋; 永井 幸代; 岩田 幸子
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2021/04 -2024/03 
    Author : 岩田 幸子
     
    乳幼児の認知機能の発達は，早産やNICU入院に代表される新生児側の因子，母体精神疾・産後うつ・育児不安などの母体側の因子，そして，母児の相互作用に強い影響を受けることが知られている．本研究は，新生児の睡眠覚醒リズムの確立過程を，睡眠同期を中心にした母児間の相互作用を通じて多面的に観察し，両者の関係性が児の遠隔期の認知機能に影響を及ぼす影響を明らかにすることを目的としている． 研究初年度は，研究計画の確定，倫理委員会の承認，症例リクルートメントの開始を目標にしていたが，新型コロナウイルス感染症のアウトブレイクによる研究施設面会制限により，症例リクルートメント開始に至らなかった．その間，倫理審査及・プロトコル改定および確定・アクチグラフをはじめとする必要モニタリング機材の整備・研究協力者のトレーニングを進め，保護者の面会制限解除と共に研究が進められるように準備を整えた．幸いにも，２０２２年３月には，大半の臨床研究の再開が可能となり，研究２年度である２０２２年４月より症例リクルートメント開始予定としている． 関連研究として，過去に実施した１か月健診を受診する母子約１３００人の質問紙評価のデータベースから，児の夜間覚醒に対する母親の対処行動が母児の睡眠に与える影響についての解析を進め，Scientific Reports誌に投稿・掲載した（Kuroda et al. 2021 Sci Rep.）．また，本研究の前提となるアクチグラフによる睡眠評価の妥当性を，睡眠ポリグラフを用いて評価した研究の成果を，Journal of Sleep Research誌に掲載した（Unno et al. 2022 J Sleep Res.）.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2018/04 -2022/03 
    Author : Iwata Sachiko
     
    This study aimed to elucidate the influence of intrauterine growth restriction to the hypothalamus-pituitary-adrenal axis in hospitalised newborns. We demonstrated that 1. cortisol levels of small for gestational age (SGA) infants were higher soon after birth and paradoxically lower after two weeks compared to those in their peers without intrauterine growth restriction, 2. myelination assessed using quantitative MRI was more matured in SGA infants, 3. higher prevalence of the autistic spectrum disorder was noted in SGA infants, 4. cot-side probes for cerebral structure, cerebral function and biological rhythms were developed for the assessment of SGA infants and other high risk infants using the near-infrared time-resolved spectroscopy and actigraphy.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2015/04 -2019/03 
    Author : Iwata Sachiko
     
    Newborn infants hospitalised at a neonatal intensive care unit (24-40 weeks gestation) were studied using time-resolved near-infrared spectroscopy (TR-NIRS). Of 150 infants studied, association between light scattering within 7 days of birth and clinical variables were assessed, where Apgar scores, cord blood pH, gestational age and requirement for mechanical ventilation showed robust relationships with light scattering. When light scattering was assessed in newborn infants, who underwent TR-NIRS measurement at term-equivalent period, light scattering still depended on variables associated with maturation at birth (e.g. gestational age and birth weight), whereas post-natal nutritional status, such as body weight gain and days before oral/tube feeding >100ml/kg/d was identified as additional independent variable of light scattering. Taken together, reduced light scattering coefficient might be determined by maturation status at birth and transitional, growth status after birth.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2012/04 -2016/03 
    Author : Iwata Sachiko; IWATA Osuke
     
    It is largely unknown how foetal biological rhythms evolve into adult-type circadian rhythms, which are observed approximately 12 weeks of life. Using actigraphy and salivary biomarkers, we observed that diurnal rhythms, which mimic those of foetuses, can be observed even shortly after birth. In a large cohort of healthy one-month-old infants and their mothers, the infant’s nighttime sleep was dependent on both maternal life styles and intrinsic variables of the infant. Taken together, development of diurnal rhythms after birth is likely to be regulated by both extrinsic stimuli (e.g. maternal melatonin and lifestyle) and intrinsic programme (e.g. genetic factors).
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2009 -2011 
    Author : IWATA Sachiko; IWATA Osuke
     
    In a study which investigated the relationship between conventional brain MRI at term and the cognitive outcome at 9 years old in very preterm-born infants, significant correlations were observed between the white matter injury and cognitive, language and motor impairment. In another study using diffusion tensor imaging at term in 82 preterm infants, fractional anisotropy of the white matter was linearly correlated with the postconception age of the infant. Participants were also assessed for the neurodevelopmental outcome at 18 and 36 months of post-natal corrected age ; detailed relationships between background clinical variables during the neonatal period including nutrition and quantitative MRI markers and neurodevelopmental outcomes are currently under analysis.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2009 -2011 
    Author : IWATA Osuke; IWATA Sachiko; OKAMURA Hisayoshi; KANDA Hiroshi; OKADA Junichiro
     
    Newborn infants are vulnerable for seizures, which are generally resistant to anti-convulsants. In our current project, we developed a large animal model of neonatal seizure by titrating the depth of hypo-ventilation insult. To assess the seizure burden following the recovery from the insult, we developed a handy telemetry video EEG system with off-line amplitude-integrated EEG exchanger software, which enabled us to quantitate the frequency and the duration of seizures. Our model would be relevant to the clinical neonatal seizures following perinatal hypoxia-ischaemia, which could be used to assess the impact of the treatment on histopathological changes in the brain as well as to develop new pharmacological treatments.

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