吉藤　歩 （ヨシフジ　アユミ）

Yoshifuji, Ayumi

写真a

所属（所属キャンパス）

医学部 感染症学教室 （信濃町）

職名

専任講師（有期）
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  • Canagliflozin protects the cardiovascular system through effects on the gut environment in non-diabetic nephrectomized rats

    Matsui A., Yoshifuji A., Irie J., Tajima T., Uchiyama K., Itoh T., Wakino S., Itoh H.

    Clinical and Experimental Nephrology （Clinical and Experimental Nephrology）  2023年

    ISSN  13421751

    　概要を見る

    Background: The gut produces toxins that contribute to the cardiovascular complications of chronic kidney disease. Canagliflozin, a sodium glucose cotransporter (SGLT) 2 inhibitor that is used as an anti-diabetic drug, has a weak inhibitory effect against SGLT1 and may affect the gut glucose concentration and environment. Methods: Here, we determined the effect of canagliflozin on the gut microbiota and the serum gut-derived uremic toxin concentrations in 5/6th nephrectomized (Nx) rats. Results: Canagliflozin increased the colonic glucose concentration and restored the number of Lactobacillus bacteria, which was low in Nx rats. In addition, the expression of tight junction proteins in the ascending colon was low in Nx rats, and this was partially restored by canagliflozin. Furthermore, the serum concentrations of gut-derived uremic toxins were significantly increased by Nx and reduced by canagliflozin. Finally, the wall of the thoracic aorta was thicker and there was more cardiac interstitial fibrosis in Nx rats, and these defects were ameliorated by canagliflozin. Conclusions: The increases in colonic glucose concentration, Lactobacillus numbers and tight junction protein expression, and the decreases in serum uremic toxin concentrations and cardiac interstitial fibrosis may have been caused by the inhibition of SGLT1 by canagliflozin because similar effects were not identified in tofogliflozin-treated rats.

  • Memory B Cells and Memory T Cells Induced by SARS-CoV-2 Booster Vaccination or Infection Show Different Dynamics and Responsiveness to the Omicron Variant

    Mise-Omata S., Ikeda M., Takeshita M., Uwamino Y., Wakui M., Arai T., Yoshifuji A., Murano K., Siomi H., Nakagawara K., Ohyagi M., Ando M., Hasegawa N., Saya H., Murata M., Fukunaga K., Namkoong H., Lu X., Yamasaki S., Yoshimura A.

    Journal of Immunology （Journal of Immunology）  209 （ 11 ） 2104 - 2113 2022年12月

    ISSN  00221767

    　概要を見る

    Although the immunological memory produced by BNT162b2 vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been well studied and established, further information using different racial cohorts is necessary to understand the overall immunological response to vaccination. We evaluated memory B and T cell responses to the severe acute respiratory syndrome coronavirus 2 spike protein before and after the third booster using a Japanese cohort. Although the Ab titer against the spike receptor-binding domain (RBD) decreased significantly 8 mo after the second vaccination, the number of memory B cells continued to increase, whereas the number of memory T cells decreased slowly. Memory B and T cells from unvaccinated infected patients showed similar kinetics. After the third vaccination, the Ab titer increased to the level of the second vaccination, and memory B cells increased at significantly higher levels before the booster, whereas memory T cells recovered close to the second vaccination levels. In memory T cells, the frequency of CXCR5+CXCR3+CCR62 circulating follicular Th1 was positively correlated with RBD-specific Ab-secreting B cells. For the response to variant RBDs, although 60-80% of memory B cells could bind to the omicron RBD, their avidity was low, whereas memory T cells show an equal response to the omicron spike. Thus, the persistent presence of memory B and T cells will quickly upregulate Ab production and T cell responses after omicron strain infection, which prevents severe illness and death due to coronavirus disease 2019.

  • Investigation for the efficacy of COVID-19 vaccine in Japanese CKD patients treated with hemodialysis

    Yoshifuji A., Toda M., Ryuzaki M., Kikuchi K., Kawai T., Sakai K., Oyama E., Koinuma M., Katayama K., Uehara Y., Ohmagari N., Kanno Y., Kon H., Shinoda T., Takano Y., Tanaka J., Hora K., Nakazawa Y., Hasegawa N., Hanafusa N., Hinoshita F., Morikane K., Wakino S., Nakamoto H., Takemoto Y.

    Renal Replacement Therapy （Renal Replacement Therapy）  8 （ 1 ）  2022年12月

    　概要を見る

    Background: Dialysis patients are predisposed to severe disease and have a high mortality rate in coronavirus disease 2019 (COVID-19) due to their comorbidities and immunocompromised conditions. Therefore, dialysis patients should be prioritized for vaccination. This study aimed to examine how long the effects of the vaccine are maintained and what factors affect antibody titers. Methods: Hemodialysis patients (HD group) and age- and sex-matched non-dialysis individuals (Control group), receiving two doses of BNT162b2 vaccine, were recruited through the Japanese Society for Dialysis Therapy (JSDT) Web site in July 2021. Anti-SARS-CoV-2 immunoglobulin (IgG) (SARS-CoV-2 IgG titers) was measured before vaccination, 3 weeks after the first vaccination, 2 weeks after the second vaccination, and 3 months after the second vaccination, and was compared between Control group and HD group. Factors affecting SARS-CoV-2 IgG titers were also examined using multivariable regression analysis and stepwise regression analysis (least AIC). In addition, we compared adverse reactions in Control and HD groups and examined the relationship between adverse reactions and SARS-CoV-2 IgG titers. Results: Our study enrolled 123 participants in the Control group (62.6% men, median age 67.0 years) and 206 patients in the HD group (64.1% men, median age 66.4 years). HD group had significantly lower SARS-CoV-2 IgG titers at 3 weeks after the first vaccination (p < 0.0001), 2 weeks after second vaccination (p = 0.0002), and 3 months after the second vaccination (p = 0.045) than Control group. However, the reduction rate of SARS-CoV-2 IgG titers between 2 weeks and 3 months after the second vaccination was significantly smaller in HD group than in Control (p = 0.048). Stepwise regression analysis revealed that dialysis time was identified as the significant independent factors for SARS-CoV-2 IgG titers at 2 weeks after the second vaccination in HD group (p = 0.002) and longer dialysis time resulted in higher maximum antibody titers. The incidences of fever and nausea after the second vaccination were significantly higher in the HD group (p = 0.039 and p = 0.020). Antibody titers in those with fever were significantly higher than those without fever in both groups (HD: p = 0.0383, Control: p = 0.0096). Conclusion: HD patients had significantly lower antibody titers than age- and sex-matched non-dialysis individuals over 3 months after vaccination. Dialysis time was identified as a factor affecting SARS-CoV-2 IgG titers in HD group, with longer dialysis time resulting in higher maximum SARS-CoV-2 IgG titers.

  • Patients with hemodialysis-induced hypoxemia had a poor prognosis of COVID-19

    Toda M., Yoshifuji A., Fujii K., Komatsu M., Kato A., Tamura I., Sugi W., Ryuzaki M.

    Renal Replacement Therapy （Renal Replacement Therapy）  8 （ 1 ）  2022年12月

    　概要を見る

    Background: We experienced that some hemodialysis (HD) patients with coronavirus disease 2019 (COVID-19) exacerbated hypoxemia during HD. Though HD-induced hypoxemia has been reported, there have been no reports of HD-induced hypoxemia in patients with COVID-19 and its effect on prognosis of COVID-19. Methods: Eleven HD patients admitted with COVID-19 from August 2020 to April 2021 were classified into the patients whose oxygen demand increased by more than 3 L/min with mask during HD (worsened group, n = 5) and others (not-worsened group, n = 6). The background, laboratory findings, severity of COVID-19 and prognosis were compared between the two groups. In addition, blood gases were measured before and after dialysis among HD patients admitted with COVID-19 on April 2021 (n = 3). Results: There were no significant differences in backgrounds, except for a higher proportion of diabetes mellitus in worsened group (p = 0.04). Although laboratory findings were not significantly different on admission day, albumin and LDH levels 7 days after admission were significantly lower and higher in worsened group, respectively (p = 0.03 and < 0.01). The severity of COVID-19 and survival rate were significantly worse in worsened group (p = 0.01 and 0.03). The alveolar-arterial oxygen pressure difference (Aa-DO2) opened during HD in a patient with HD-induced hypoxemia, but did not open in patients without HD-induced hypoxemia. Conclusions: There is a close relationship among HD-induced hypoxemia and poor prognosis of COVID-19. The HD-induced hypoxemia of patients with COVID-19 may be caused by ventilation/perfusion mismatching.

  • The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force

    Wang Q.S., Edahiro R., Namkoong H., Hasegawa T., Shirai Y., Sonehara K., Tanaka H., Lee H., Saiki R., Hyugaji T., Shimizu E., Katayama K., Kanai M., Naito T., Sasa N., Yamamoto K., Kato Y., Morita T., Takahashi K., Harada N., Naito T., Hiki M., Matsushita Y., Takagi H., Ichikawa M., Nakamura A., Harada S., Sandhu Y., Kabata H., Masaki K., Kamata H., Ikemura S., Chubachi S., Okamori S., Terai H., Morita A., Asakura T., Sasaki J., Morisaki H., Uwamino Y., Nanki K., Uchida S., Uno S., Nishimura T., Ishiguro T., Isono T., Shibata S., Matsui Y., Hosoda C., Takano K., Nishida T., Kobayashi Y., Takaku Y., Takayanagi N., Ueda S., Tada A., Miyawaki M., Yamamoto M., Yoshida E., Hayashi R., Nagasaka T., Arai S., Kaneko Y., Sasaki K., Tagaya E., Kawana M., Arimura K., Takahashi K., Anzai T., Ito S., Endo A., Uchimura Y., Miyazaki Y., Honda T., Tateishi T., Tohda S., Ichimura N., Sonobe K., Sassa C.T., Nakajima J., Nakano Y., Nakajima Y., Anan R., Arai R., Kurihara Y., Harada Y., Nishio K., Ueda T., Azuma M., Saito R., Sado T., Miyazaki Y., Sato R., Haruta Y., Nagasaki T., Yasui Y., Hasegawa Y., Mutoh Y., Kimura T., Sato T.

    Nature Communications （Nature Communications）  13 （ 1 ）  2022年12月

    　概要を見る

    Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection.

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  • 先端医科学研究

    2025年度

  • 臨床病態学

    2025年度

  • 感染症学

    2025年度

  • 身体の構造と機能

    2025年度

  • 先端医科学研究

    2024年度

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