Masahiro Yamazaki

Dr. Masahiro Yamazaki


Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

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

Representative Publications

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22 October 2021 in Nutrients
Verified
Journal Article
Open access
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TFTakahashi Fuyuko
Takahashi Fuyuko
Yoshitaka HashimotoYoshitaka Hashimoto
Yoshitaka Hashimoto
AKAyumi Kaji
Ayumi Kaji
RSRyosuke Sakai
Ryosuke Sakai
YKYuka Kawate
Yuka Kawate
Michiaki FukuiMichiaki Fukui
Michiaki Fukui
The aim of this cross-sectional study was to examine the association between the geriatric nutritional risk index (GNRI) and the prevalence of sarcopenia in people with type 2 diabetes (T2DM). Having both low handgrip strength (<28 kg for men and <18 kg for women) and low skeletal muscle mass index (<7.0 kg/m2 for men and <5.7 kg/m2 for women) was diagnosed as sarcopenia. GNRI was estimated by the formula as below: GNRI = (1.489 × serum albumin level [g/L]) + (41.7 × [current body weight (kg)/ideal body weight (kg)]). Participants were dichotomized on the basis of their GNRI scores (GNRI < 98, low; or GNRI ≥ 98, high). Among 526 people (301 men and 225 women) with T2DM, the proportions of participants with sarcopenia and low GNRI were 12.7% (n = 67/526) and 5.1% (n = 27/526), respectively. The proportion of sarcopenia in participants with low-GNRI was higher than that with high GNRI (44.4% [n = 12/27] vs. 11.0% [n = 55/499], p < 0.001). The GNRI showed positive correlations with handgrip strength (r = 0.232, p < 0.001) and skeletal muscle mass index (r = 0.514, p < 0.001). Moreover, low GNRI was related to the prevalence of sarcopenia (adjusted odds ratio, 4.88 [95% confidence interval: 1.88–12.7], p = 0.001). The GNRI, as a continuous variable, was also related to the prevalence of sarcopenia (adjusted odds ratio, 0.89 [95% confidence interval: 0.86–0.93], p < 0.001). The present study revealed that low GNRI was related to the prevalence of sarcopenia.

Verified
Journal Article
Open access
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RKRena Kawano
Rena Kawano
TOTakuro Okamura
Takuro Okamura
Yoshitaka HashimotoYoshitaka Hashimoto
Yoshitaka Hashimoto
SMSaori Majima
Saori Majima
TSTakafumi Senmaru
Takafumi Senmaru
Michiaki FukuiMichiaki Fukui
Michiaki Fukui
Background: Erythritol, a sugar alcohol, is widely used as a substitute for sugar in diets for patients with diabetes or obesity. Methods: In this study, we aimed to investigate the effects of erythritol on metabolic disorders induced by a high-fat diet in C57BL/6J mice, while focusing on changes in innate immunity. Results: Mice that were fed a high-fat diet and administered water containing 5% erythritol (Ery group) had markedly lower body weight, improved glucose tolerance, and markedly higher energy expenditure than the control mice (Ctrl group) (n = 6). Furthermore, compared with the Ctrl group, the Ery group had lesser fat deposition in the liver, smaller adipocytes, and significantly better inflammatory findings in the small intestine. The concentrations of short-chain fatty acids (SCFAs), such as acetic acid, propanoic acid, and butanoic acid, in the serum, feces, and white adipose tissue of the Ery group were markedly higher than those in the Ctrl group. In flow cytometry experiments, group 3 innate lymphoid cell (ILC3) counts in the lamina propria of the small intestine and ILC2 counts in the white adipose tissue of the Ery group were markedly higher than those in the Ctrl group. Quantitative real-time reverse transcription polymerase chain reaction analyses showed that the Il-22 expression in the small intestine of the Ery group was markedly higher than that in the Ctrl group. Conclusions: Erythritol markedly decreased metabolic disorders such as diet-induced obesity, glucose intolerance, dyslipidemia, and fat accumulation in the mouse liver by increasing SCFAs and modulating innate immunity.

11 September 2020 in Life
Verified
Journal Article
Open access
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HNHanako Nakajima
Hanako Nakajima
FTfumie takewaki
fumie takewaki
Yoshitaka HashimotoYoshitaka Hashimoto
Yoshitaka Hashimoto
SKShizuo Kajiyama
Shizuo Kajiyama
SMSaori Majima
Saori Majima
Michiaki FukuiMichiaki Fukui
Michiaki Fukui
Metformin is reported to affect human gut microbiota; however, the nature of this association in Japanese patients with type 2 diabetes mellitus (T2DM) is unknown. We enrolled 31 patients with T2DM who took metformin for the first time in this study. We compared them before and after four weeks of taking metformin. Fecal samples were collected and 16S rDNA sequences were performed to identify the gut microbiota. Blood samples and Gastrointestinal Symptom Rating Scale (GSRS) questionnaire results, denoting gastro-intestinal symptoms, were also collected. In the whole-group analysis, no significant differences were found at the phylum level. In a subgroup of 21 patients that excluding those using medications affecting gut microbiota, there was a significant decrease of the phylum Firmicutes (p = 0.042) and of the ratio of the Firmicutes and Bacteroidetes abundances (p = 0.04) after taking metformin. Changes in abdominal pain (r = −0.56, p = 0.008) and regurgitation (r = −0.53, p = 0.01) were associated with Parabacteroides. Despite there being no direct association with abdominal symptoms, our study revealed that the composition of gut microbiota in Japanese individuals with T2DM partially changed after starting metformin.

8 February 2016 in Journal of Sleep Research
Verified
Journal Article
Open access
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MKMayuko Kadono
Mayuko Kadono
NNNaoko Nakanishi
Naoko Nakanishi
MYMasahiro Yamazaki
Masahiro Yamazaki
GHGoji Hasegawa
Goji Hasegawa
NNNaoto Nakamura
Naoto Nakamura
Michiaki FukuiMichiaki Fukui
Michiaki Fukui
Summary: Disruptions to sleep and circadian rhythms have now been recognized as common comorbidities in patients with medical illnesses. We aimed to determine if the diurnal rhythms for rest and activity were disrupted in parallel with the development of diabetic complications. Ninety outpatients in our diabetes clinic who had a body mass index <25 kg m2 wore an actigraph for 7 consecutive days (42 men; mean age 68.7 ± 8.2 years). Patients with neuropsychiatric diseases, liver cirrhosis, renal failure, chronic obstructive pulmonary disease or blindness, or those who performed shiftwork were excluded. We grouped the actigraph recordings into 1‐h periods and counted the number of minutes that showed activity. Stepwise regression analysis showed an association between a diabetic clinical background and measurements of circadian rhythms such as daytime activity, night‐time activity, phase, interdaily stability, intradaily variability and relative amplitude. Higher age, body mass index, total cholesterol levels and insulin usage were associated with lower daytime activity and higher intradaily variability, whereas higher haemoglobin A1c levels and the presence of neuropathy were associated with greater daytime activity. The presence of proliferative retinopathy and increased levels of microalbuminuria were associated with higher intradaily variability and lower interdaily stability and amplitude. The presence of cardiovascular disease was associated with advanced phase, whereas painful neuropathy was associated with delayed phase. Our study demonstrated that different diabetic complications were associated independently with a variety of alterations in the circadian rest and activity rhythms. Our findings have provided novel insights that may be helpful in developing interventions for sleep–wake disorders associated with diabetes.

19 June 2021 in Nutrients
Verified
Journal Article
Open access
PDF file
FTfumie takewaki
fumie takewaki
HNHanako Nakajima
Hanako Nakajima
DTDaiki Takewaki
Daiki Takewaki
Yoshitaka HashimotoYoshitaka Hashimoto
Yoshitaka Hashimoto
SMSaori Majima
Saori Majima
Michiaki FukuiMichiaki Fukui
Michiaki Fukui
The aim of this research was to reveal the characteristics of gut microbiome altered by acarbose intervention in Japanese patients with type 2 diabetes (T2D) and its possible association with habitual dietary intake. Eighteen patients with T2D were administered acarbose for four weeks. The abundances of two major phyla, namely Actinobacteria and Bacteroidetes, were reciprocally changed accompanied by the acarbose intervention. There were also significant changes in the abundances of ten genera, including the greater abundance of Bifidobacterium, Eubacterium, and Lactobacillus and the lower abundance of Bacteroides in the group after the intervention than that before the intervention. Hierarchical clustering of habitual dietary intake was performed based on the pattern of changes in the gut microbiota and were classified into distinct three clusters. Cluster I consisted of sucrose, cluster II mainly included fat intake, and cluster III mainly included carbohydrate intake. Moreover, the amount of change in Faecalibacterium was positively correlated with the intake of rice, but negatively correlated with the intake of bread. The intake of potato was negatively correlated with the amount of change in Akkermansia and Subdoligranulum. Acarbose altered the composition of gut microbiome in Japanese patients with T2D, which might be linked to the habitual dietary intake.

5 May 2014 in Diabetology & Metabolic Syndrome
Verified
Journal Article
Open access
PDF file
MYMasahiro Yamazaki
Masahiro Yamazaki
GHGoji Hasegawa
Goji Hasegawa
SMSaori Majima
Saori Majima
KMKazuteru Mitsuhashi
Kazuteru Mitsuhashi
TFTakuya Fukuda
Takuya Fukuda
NNNaoto Nakamura
Naoto Nakamura
Hemoglobin A1c is the main treatment target for patients with type 2 diabetes. It has also been shown recently that postprandial glucose and daily glucose fluctuations affect the progression of diabetic complications and atherosclerotic damages. Continuous glucose monitoring was performed in patients with type 2 diabetes to evaluate the efficacy of repaglinide vs. glimepiride on postprandial glucose spikes and fluctuations. A total of 10 Japanese patients with type 2 diabetes treated with glimepiride monotherapy were enrolled. After observation period for 8 weeks, glimepiride was changed to repaglinide. Continuous glucose monitoring was performed whilst consuming calorie-restricted diets for two days at baseline and at the end of the 12-week trial. Blood and urine samples were collected for measurement of glucose control parameters and inflammatory and oxidative stress markers on the last day of taking either glimepiride or repaglinide. Nine patients completed the trial. Although the glucose control parameters were not significantly different between glimepiride and repaglinide, the mean amplitude of glycemic excursions measured by continuous glucose monitoring was significantly reduced by changing treatment from glimepiride to repaglinide. The levels of plasminogen activator inhibitor-1, high sensitivity C-reactive protein, and urinary 8-hydoroxydeoxyguanosine were reduced significantly by repaglinide treatment. These results suggest that repaglinide may decrease the risk of cardiovascular disease in type 2 diabetes by minimizing glucose fluctuations thereby reducing inflammation and oxidative stress.