Yoshifuji, Ayumi



School of Medicine, Department of Infectious Diseases (Shinanomachi)


Senior Assistant Professor (Non-tenured)/Assistant Professor (Non-tenured)


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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

    ISSN  13421751

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    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 2022.12

    ISSN  00221767

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    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.

  • 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 )  2022.12

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    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.

  • Ceftazidime encephalopathy developed without the elevation of cerebrospinal fluid concentration of ceftazidime: A case report of two cases

    Toda M., Yoshifuji A., Hosoya K., Taguchi K., Komatsu M., Kobayashi E., Fujii K., Kato A., Hasegawa N., Matsumoto K., Ryuzaki M.

    Journal of Infection and Chemotherapy (Journal of Infection and Chemotherapy)  28 ( 12 ) 1667 - 1671 2022.12

    ISSN  1341321X

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    Background: Ceftazidime encephalopathy is reported to be caused by the repeated administration of ceftazidime in patients with renal impairment because of the high serum concentration of ceftazidime. Ceftazidime encephalopathy has been considered to be caused by the elevation of the cerebrospinal fluid (CSF) concentration. However, as no reports have measured CSF concentrations, the relationship with ceftazidime encephalopathy and CSF concentration has not been clarified. Case presentation: Case 1: An 80-year-old Japanese man under a combination therapy with peritoneal dialysis and hemodialysis, who had been treated for a cellulitis with ceftazidime, developed altered consciousness and was diagnosed as ceftazidime encephalopathy. His serum concentration of ceftazidime was elevated, but CSF concentration was only under 0.1 μg/mL. Case 2: An 88-year-old Japanese man with chronic kidney disease, who had been treated for a urinary tract infection with ceftazidime, developed altered consciousness and was diagnosed as ceftazidime encephalopathy. His serum concentration of ceftazidime was elevated, but CSF concentration was within the therapeutic range. However, his serum and CSF concentration of quinolinic acid was markedly increased. Conclusions: Patients with renal failure are more likely to develop ceftazidime encephalopathy. We need to pay attention to the dosage of ceftazidime and to the appearance of neurological symptoms. Ceftazidime encephalopathy was considered to be caused by the high CSF concentration, but it could be caused by quinolinic acid as neurotoxic substance.

  • Committee report: Questionnaire survey on the treatment of COVID-19 in patients receiving dialysis therapy

    Yoshifuji A., Ryuzaki M., Uehara Y., Ohmagari N., Kawai T., Kanno Y., Kikuchi K., Kon H., Sakai K., 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 )  2022.12

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    Background: Patients with coronavirus disease 2019 (COVID-19) who receive dialysis therapy develop more severe disease and have a poorer prognosis than patients who do not. Although various data on the treatment of patients not receiving dialysis therapy have been reported, clinical practice for patients on dialysis is challenging as data is limited. The Infection Control Committee of the Japanese Society for Dialysis Therapy decided to clarify the status of treatment in COVID-19 patients on dialysis. Methods: A questionnaire survey of 105 centers that had treated at least five COVID-19 patients on dialysis was conducted in August 2021. Results: Sixty-six centers (62.9%) responded to the questionnaire. Antivirals were administered in 27.7% of facilities treating mild disease (most patients received favipiravir) and 66.7% of facilities treating moderate disease (most patients with moderate or more severe conditions received remdesivir). Whether and how remdesivir is administered varies between centers. Steroids were initiated most frequently in moderate II disease (50.8%), while 43.1% of the facilities initiated steroids in mild or moderate I disease. The type of steroid, dose, and the duration of administration were generally consistent, with most facilities administering dexamethasone 6 mg orally or 6.6 mg intravenously for 10 days. Steroid pulse therapy was administered in 48.5% of the facilities, and tocilizumab was administered in 25.8% of the facilities, mainly to patients on ventilators or equivalent medications, or to the cases of exacerbations. Furthermore, some facilities used a polymethylmethacrylate membrane during dialysis, nafamostat as an anticoagulant, and continuous hemodiafiltration in severe cases. There was limited experience of polymyxin B-immobilized fiber column-direct hemoperfusion and extracorporeal membrane oxygenation. The discharge criteria for patients receiving dialysis therapy were longer than those set by the Ministry of Health, Labor and Welfare in 22.7% of the facilities. Conclusions: Our survey revealed a variety of treatment practices in each facility. Further evidence and innovations are required to improve the prognosis of patients with COVID-19 receiving dialysis therapy.

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