TATSUYA MIKAMI

Dr. TATSUYA MIKAMI

orcid

Research Focus & Metrics

Academic Career Length

26Years (2001-Present)

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

Representative Publications

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4 August 2021 in Brain Sciences
Verified
Journal Article
Open access
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NONaoki Ozato
Naoki Ozato
SSShinichiro Saito
Shinichiro Saito
TYTohru Yamaguchi
Tohru Yamaguchi
MKMitsuhiro Katashima
Mitsuhiro Katashima
MMMina Misawa
Mina Misawa
SNShigeyuki Nakaji
Shigeyuki Nakaji
Visceral fat accumulation is an independent risk factor for cardiovascular disease and mortality. Visceral fat is a causal risk factor for hypertension and type 2 diabetes, which was reported as one of the risk factors for dementia. Visceral fat areas (VFA) might be clinically important to prevent dementia; however, the association between VFA and cognitive function in the elderly remains unknown. We aimed to evaluate the association between brain structural abnormalities using magnetic resonance imaging (MRI) and VFA, and the association between cognitive function and VFA, in the elderly. A total of 2364 healthy individuals were enrolled, and we excluded those diagnosed with dementia. Participants were divided into a high-VFA and a low-VFA group based on median VFA. The high-VFA group had significantly lower cognitive function than the low-VFA group (p = 0.025), after adjustment for related factors using a linear regression model. Regarding brain structure in MRI, VFA remained significantly associated with white matter lesions (odds ratio (OR), 1.90; 95% confidence interval (1.33–2.70); adjusted p < 0.001) and perivascular space (OR, 1.28; 95% confidence interval (1.02–1.61); adjusted p = 0.033). Further follow-up studies are needed, but reducing visceral fat might be important, not only to prevent cardiovascular disease but also to prevent dementia.

18 June 2021 in Journal of Gastroenterology
Verified
Journal Article
Closed access
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TMTamotsu Matsuhashi
Tamotsu Matsuhashi
WHWaku Hatta
Waku Hatta
THTakuto Hikichi
Takuto Hikichi
SFSho Fukuda
Sho Fukuda
TMTATSUYA MIKAMI
TATSUYA MIKAMI
KIKatsunori Iijima
Katsunori Iijima

16 July 2022 in Allergology International
Verified
Journal Article
Open access
TYTaimu Yamaguchi
Taimu Yamaguchi
ANAyami Nomura
Ayami Nomura
AMAtsushi Matsubara
Atsushi Matsubara
THTakayoshi Hisada
Takayoshi Hisada
YTYoshinori Tamada
Yoshinori Tamada
MIMizuri Ishida
Mizuri Ishida
Decreased gut microbiota diversity is associated with gut dysbiosis and causes various diseases, including allergic diseases. We investigated the relationship between gut microbial diversity and sensitization to major inhaled allergens. Furthermore, the relationship of allergic symptom onset with bacterial composition in sensitized individuals was investigated. This study included 1092 local residents who had participated in the Iwaki Health Promotion Project in 2016. Blood samples were analyzed to ascertain specific IgE levels against major inhaled allergens (JCP, HD1, Grass-mix, Weed-mix). Nasal symptoms were estimated by questionnaires. Fecal samples were analyzed for bacterial 16S rRNA using next generation sequencing. The diversity index (α-diversity, β-diversity) and the composition of gut microbes in phylum/order levels were compared between patients sensitized or unsensitized to allergen, and symptomatic and asymptomatic groups. Some α-diversity metrics were significantly decreased in patients who were sensitized to any/all four allergens compared with the unsensitized group. β-diversity differed significantly between those unsensitized and sensitized to all allergens (aged 20-49 years), and between those unsensitized and sensitized to any/all four allergens (aged ≥50 years). The relative abundance of Bacteroidales was significantly lower in the unsensitized than in the sensitized group. The composition and diversity of gut microbiota were similar between the symptomatic and asymptomatic groups. Our results suggest that lack of diversity in gut microbiota has an effect on sensitization to allergens. Bacteroidales in order level may affect sensitization; however, the onset of allergy symptoms was not significantly associated with bacterial composition and diversity.

7 August 2022 in Metabolites
Verified
Journal Article
Open access
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MTMasaya Tsubokawa
Masaya Tsubokawa
MNMiyuki Nishimura
Miyuki Nishimura
TMTATSUYA MIKAMI
TATSUYA MIKAMI
MIMizuri Ishida
Mizuri Ishida
THTakayoshi Hisada
Takayoshi Hisada
YTYoshinori Tamada
Yoshinori Tamada
The gut microbiota has become a significant factor associated with health and disease. Although many studies have reported the implications of changes in the gut microbiota on cardiovascular diseases, there are no reports on the relationship between heart rate variability (HRV) and the gut microbiota. Therefore, we investigated the association between gut microbiota abundance and HRV parameters in this cross-sectional study of the general Japanese population. This study included 950 participants of the Iwaki Health Promotion Project who underwent a medical examination in 2019 that included HRV and gut microbiota measurements. At the genus level, multivariate regression analysis showed that higher gut microbial diversity was associated with a higher standard deviation of RR intervals (SDNN). Moreover, a higher SDNN was associated with a higher relative count of Lachnospiraceae incertae sedis. L. incertae sedis abundance was associated with higher HRV parameters such as SDNN, coefficient of variation of RR intervals, low-frequency component power (LF)/high-frequency component power, and LF. In the general Japanese population, higher gut microbial diversity and L. incertae sedis abundance were associated with higher HRV parameters.

9 February 2023 in Metabolites
Verified
Journal Article
Open access
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NFNobuo Fuke
Nobuo Fuke
TYTakahiro Yamashita
Takahiro Yamashita
SSSunao Shimizu
Sunao Shimizu
MMMai Matsumoto
Mai Matsumoto
KSKaori Sawada
Kaori Sawada
HSHiroyuki Suganuma
Hiroyuki Suganuma
The influx of intestinal bacteria-derived lipopolysaccharide (LPS) into the blood has attracted attention as a cause of diseases. The aim of this study is investigating the associations between the influx of LPS, dietary factors, gut microbiota, and health status in the general adult population. Food/nutrient intake, gut microbiota, health status and plasma LPS-binding protein (LBP; LPS exposure indicator) were measured in 896 residents (58.1% female, mean age 54.7 years) of the rural Iwaki district of Japan, and each correlation was analyzed. As the results, plasma LBP concentration correlated with physical (right/left arms’ muscle mass [β = −0.02, −0.03]), renal (plasma renin activity [β = 0.27], urine albumin creatinine ratio [β = 0.50]), adrenal cortical (cortisol [β = 0.14]), and thyroid function (free thyroxine [β = 0.05]), iron metabolism (serum iron [β = −0.14]), and markers of lifestyle-related diseases (all Qs < 0.20). Plasma LBP concentration were mainly negatively correlated with vegetables/their nutrients intake (all βs ≤ −0.004, Qs < 0.20). Plasma LBP concentration was positively correlated with the proportion of Prevotella (β = 0.32), Megamonas (β = 0.56), and Streptococcus (β = 0.65); and negatively correlated with Roseburia (β = −0.57) (all Qs < 0.20). Dietary factors correlated with plasma LBP concentration correlated with positively (all βs ≥ 0.07) or negatively (all βs ≤ −0.07) the proportion of these bacteria (all Qs < 0.20). Our results suggested that plasma LBP concentration in the Japanese general adult population was associated with various health issues, and that dietary habit was associated with plasma LBP concentration in relation to the intestinal bacteria.

1 September 2021 in Clinical and Translational Gastroenterology
Verified
Journal Article
Open access
MSMitsushige Sugimoto
Mitsushige Sugimoto
WHWaku Hatta
Waku Hatta
YTYosuke Tsuji
Yosuke Tsuji
TYToshiyuki Yoshio
Toshiyuki Yoshio
YYYohei Yabuuchi
Yohei Yabuuchi
Takashi KawaiTakashi Kawai
Takashi Kawai
INTRODUCTION: As the aging of people in a society advances, the number of elderly patients older than 80 years in Japan with gastric cancer continues to increase. Although delayed ulcer bleeding is a major adverse event after endoscopic submucosal dissection (ESD), little is known about characteristic risk factors for bleeding in elderly patients undergoing ESD. This study aimed to evaluate risk factors for delayed bleeding after ESD for gastric cancer in elderly patients older than 80 years. METHODS: We retrospectively evaluated the incidence of delayed bleeding after ESD in 10,320 patients with early-stage gastric cancer resected by ESD between November 2013 and January 2016 at 33 Japanese institutions and investigated risk factors for delayed bleeding in elderly patients older than 80 years. RESULTS: The incidence of delayed bleeding in elderly patients older than 80 years was 5.7% (95% confidence interval [CI]: 4.6%–6.9%, 95/1,675), which was significantly higher than that in nonelderly (older than 20 years and younger than 80 years) patients (4.5%, 4.1%–5.0%, 393/8,645). Predictive factors for ESD-associated bleeding differed between nonelderly and elderly patients. On multivariate analysis of predictive factors at the time of treatment, risk factors in elderly patients were hemodialysis (odds ratio: 4.591, 95% CI: 2.056–10.248, P < 0.001) and warfarin use (odds ratio: 4.783, 95% CI: 1.689–13.540, P = 0.003). DISCUSSION: This multicenter study found that the incidence of delayed bleeding after ESD in Japanese patients older than 80 years was high, especially in patients receiving hemodialysis and taking warfarin. Management of ESD to prevent delayed bleeding requires particular care in patients older than 80 years.