Faculty Profiles - FURUHASHI Kazuhiro

Prognosis of microscopic polyangiitis is well predictable in the first 2 weeks of treatment Reviewed

Owaki, A; Tanaka, A; Furuhashi, K; Watanabe, Y; Koshi-Ito, E; Imaizumi, T; Maruyama, S

CLINICAL AND EXPERIMENTAL NEPHROLOGY Vol. 28 ( 7 ) page： 701 - 706 2024.7

Language：English Publisher：Clinical and Experimental Nephrology

Background: Kidney and life outcomes remain unsatisfactory in patients with microscopic polyangiitis (MPA). Appropriate treatment intensity must be provided to the appropriate patients. To identify severe cases early, we investigated the factors related to kidney and life outcomes. Methods: We included patients diagnosed with MPA based on myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) positivity and kidney histopathology results after kidney biopsies between January 1, 2021, and May 11, 2023, at 10 affiliated centers, including our hospital. Death, maintenance dialysis, and estimated glomerular filtration rate (eGFR) < 15 after 6 months of treatment were defined as poor prognosis groups, and factors associated with these conditions were investigated. Results: We included 84 (36 men and 48 women) patients in this study. Median age was 73.8 (interquartile range: 71–81) years. After 6 months of treatment, the proportion of patients in the poor prognosis group was 16.7 %, with a mortality of 7.1 % and a poor kidney prognosis rate of 9.5 %. Area under the receiver operating characteristic curve showed that eGFR at 2 weeks had a comparable prognostic performance equal as eGFR at 4 weeks (area under the curve: 0.875 and 0.896, respectively). After adjustment by various factors, eGFR at 2 weeks was related with prognosis significantly (p = 0.031). Conclusion: Kidney function 2 weeks after the start of treatment for MPA can predict prognosis.

DOI： 10.1007/s10157-024-02522-6

Safety and Tolerability of adipose-derived mesenchymal stem cell "ADR-001" in the treatment of immunoglobulin A nephropathy Reviewed

Maruyama, S; Tanaka, A; Furuhashi, K; Fujieda, K; Maeda, K; Mimura, T; Saka, Y; Naruse, T; Ishimoto, T; Kosugi, T

NEPHROLOGY DIALYSIS TRANSPLANTATION Vol. 39 page： I740 - I740 2024.5

Proliferative glomerulonephritis with monoclonal immunoglobulin deposits and atypical pathological findings treated with corticosteroid and rituximab Reviewed

Mori, M; Tanaka, A; Maeda, K; Saito, S; Furuhashi, K; Maruyama, S

CEN CASE REPORTS Vol. 13 ( 2 ) page： 128 - 134 2024.4

Language：English Publisher：CEN Case Reports

A 16-year-old girl with fever that appeared after taking the second COVID-19 vaccine presented to the clinic with a serum creatinine of 0.89 mg/dL and C-reactive protein of 6.9 mg/dL. She had proteinuria and microscopic hematuria, with slowly worsening kidney function. Her kidney biopsy showed fibrocellular crescents in seven of nine glomeruli that were observed under light microscopy. Another glomerulus showed endocapillary hypercellularity and mesangial cell proliferation. Electron-dense deposits were significant in the mesangial area, with monoclonal IgG1-κ and C3 deposition by immunofluorescence. The patient was diagnosed with proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) and atypical pathological finding of diffuse crescent formation. The treatment regimen for PGNMID has not yet been established, and the appropriate duration of treatment is unknown. In our case, considering that rituximab acts by binding to CD20 on the surface of B cells through its crystallizable fragment, it was administered in addition to prednisolone, which successfully decreased the proteinuria over time.

DOI： 10.1007/s13730-023-00813-7

Mortality and hyperkalaemia-associated hospitalisation in patients with chronic kidney disease: comparison of sodium zirconium cyclosilicate and sodium/calcium polystyrene sulfonate Reviewed

Onogi, C; Watanabe, Y; Tanaka, A; Furuhashi, K; Maruyama, S

CLINICAL KIDNEY JOURNAL Vol. 17 ( 2 ) page： sfae021 2024.2

Language：English Publisher：Clinical Kidney Journal

Background. Sodium zirconium cyclosilicate( SZC) , a novel drug used for treating hyperkalaemia, is effective in reducing serum potassium levels. The effects of potassium adsorbents on the mortality and hyperkalaemia-associated hospitalisation rates remain unclear. We aimed to examine how mortality and hyperkalaemia-associated hospitalisation rates vary with usage of various potassium adsorbents. Methods. This retrospective study used patients' data between April 2008 and August 2021 obtained from a large-scale Japanese medical claims database. Consecutive patients with chronic kidney disease( CKD) prescribed potassium adsorbents were enrolled and divided into three groups according to the adsorbent type [SZC, calcium polystyrene sulfonate( CPS) , and sodium polystyrene sulfonate( SPS) ] and were observed for 1 year. The primary outcome was a composite of mortality and hyperkalaemia-associated hospitalisation. Results. In total, 234, 54 183, and 18 692 patients were prescribed SZC, CPS, and SPS, respectively. The SZC group showed a higher event-free survival rate than the other two groups. The hazard ratio for the primary outcome in the CPS and SPS groups was similar in the analyses of the subgroups of patients who did not receive renal replacement therapy and those who received haemodialysis. The SZC group had a higher renin-angiotensin-aldosterone system inhibitors( RAASi) continuation rate compared to CPS and SPS groups, the difference being especially significant for SPS. Conclusions. This real-world study demonstrated the therapeutic effect of SZC in reducing mortality and hyperkalaemia-associated hospitalisations. The high RAASi continuation rate in the SZC group might be a contributing factor for improvement of the primary outcome.

DOI： 10.1093/ckj/sfae021

Establishment of an adverse effect prevention protocol on plasma exchange using fresh frozen plasma prior to ABO-incompatible living donor kidney transplantation at our hospital Reviewed

Akihito Tanaka, Yu Watanabe, Kazuhiro Furuhashi, Shoji Saito, Yoshinari Yasuda, Tomoki Kosugi, Yuta Sano, Masashi Kato, Shoichi Maruyama

Therapeutic Apheresis and Dialysis Vol. 28 ( 1 ) page： 152 - 157 2024.2

Language：English Publishing type：Research paper (scientific journal)

Introduction: Simple plasma exchange (PE) with fresh-frozen plasma replacement allows antibody removal for ABO-incompatible living donor kidney transplantation, but is associated with a high incidence of allergic reactions. We developed, implemented, and evaluated a protocol for safe preoperative PE. Methods: The protocol comprised pretreatment (125 mg methylprednisolone infusion, 400 mg acetaminophen and 30 mg diphenhydramine orally) with a replacement fluid rate < 20 mL/min. Allergic reaction incidence was investigated in controls who underwent ABO-incompatible living donor kidney transplantation between 2016 and March 2020 (group C) and patients who underwent the protocol and procedure between April 2020 and February 2023 (group N). Results: Ten (group C) and 19 (group N) patients performed 11 and 30 sessions of PE, respectively. Allergic reactions occurred in 81.8% and 36.7% (p = 0.014), respectively, with an odds ratio of the protocol was 0.056 (95% CI 0.0059–0.5380, P = 0.013). Conclusion: Our protocol resulted in a significantly lower incidence of allergic reactions.

DOI： 10.1111/1744-9987.14071

Meflin is a marker of pancreatic stellate cells involved in fibrosis and epithelial regeneration in the pancreas Reviewed

Ando, R; Shiraki, Y; Miyai, Y; Shimizu, H; Furuhashi, K; Minatoguchi, S; Kato, K; Kato, A; Iida, T; Mizutani, Y; Ito, K; Asai, N; Mii, S; Esaki, N; Takahashi, M; Enomoto, A

JOURNAL OF PATHOLOGY Vol. 262 ( 1 ) page： 61 - 75 2024.1

Language：English Publisher：Journal of Pathology

Pancreatic stellate cells (PSCs) are stromal cells in the pancreas that play an important role in pancreatic pathology. In chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC), PSCs are known to get activated to form myofibroblasts or cancer-associated fibroblasts (CAFs) that promote stromal fibroinflammatory reactions. However, previous studies on PSCs were mainly based on the findings obtained using ex vivo expanded PSCs, with few studies that addressed the significance of in situ tissue-resident PSCs using animal models. Their contributions to fibrotic reactions in CP and PDAC are also lesser-known. These limitations in our understanding of PSC biology have been attributed to the lack of specific molecular markers of PSCs. Herein, we established Meflin (Islr), a glycosylphosphatidylinositol-anchored membrane protein, as a PSC-specific marker in both mouse and human by using human pancreatic tissue samples and Meflin reporter mice. Meflin-positive (Meflin+) cells contain lipid droplets and express the conventional PSC marker Desmin in normal mouse pancreas, with some cells also positive for Gli1, the marker of pancreatic tissue-resident fibroblasts. Three-dimensional analysis of the cleared pancreas of Meflin reporter mice showed that Meflin+ PSCs have long and thin cytoplasmic protrusions, and are localised on the abluminal side of vessels in the normal pancreas. Lineage tracing experiments revealed that Meflin+ PSCs constitute one of the origins of fibroblasts and CAFs in CP and PDAC, respectively. In these diseases, Meflin+ PSC-derived fibroblasts showed a distinctive morphology and distribution from Meflin+ PSCs in the normal pancreas. Furthermore, we showed that the genetic depletion of Meflin+ PSCs accelerated fibrosis and attenuated epithelial regeneration and stromal R-spondin 3 expression, thereby implying that Meflin+ PSCs and their lineage cells may support tissue recovery and Wnt/R-spondin signalling after pancreatic injury and PDAC development. Together, these data indicate that Meflin may be a marker specific to tissue-resident PSCs and useful for studying their biology in both health and disease. © 2023 The Pathological Society of Great Britain and Ireland.

DOI： 10.1002/path.6211

Current status of low-density lipoprotein apheresis treatment for patients with peripheral artery disease and chronic kidney disease in Japanese clinical database Reviewed

Watanabe, Y; Tanaka, A; Furuhashi, K; Maruyama, S

THERAPEUTIC APHERESIS AND DIALYSIS Vol. 27 ( 6 ) page： 1000 - 1009 2023.12

Language：English Publisher：Therapeutic Apheresis and Dialysis

Introduction: Patients with peripheral arterial disease (PAD) have a poorer prognosis than those without PAD. PAD complications worsen the prognosis of patients with chronic kidney disease (CKD), especially those on maintenance dialysis. Although low-density lipoprotein apheresis (LDL-A) is expected to be effective in treating severe PAD, there are no large-scale reports on the prognosis of patients undergoing LDL-A. Methods: We obtained a clinical database from April 2008 to August 2021 and selected 924 238 patients with CKD. We selected patients with disease codes of lower limb arteriosclerosis obliterans, arteriosclerosis obliterans, and critical limb ischemia or foot ulcer. Patients who were prescribed antithrombotic medications were included. Patients who used steroids were excluded. Among these patients, those undergoing blood purification considered LDL-A were selected, and their current status was investigated. Results: We included 147 patients (113 males and 34 females). The mean patient age was 70 ± 10 years. Diabetes mellitus was present in 86%, ischemic heart disease in 34%, and stroke in 48%. Maintenance dialysis patients accounted for 86% of the patients. Statins were administered to 40% of the patients, and bypass surgery was performed in 2.7%. The median observation period was 812 days, and the mortality rate was 41%. Conclusion: LDL-A was performed in a small population of patients with CKD with the most severe form of PAD. The prognosis for these patients is extremely poor. Therefore, strategies to improve prognosis are important.

DOI： 10.1111/1744-9987.14046

Mesenchymal stem/stromal cells generated from induced pluripotent stem cells are highly resistant to senescence Reviewed

Aoi, T; Tanaka, A; Furuhashi, K; Ikeya, M; Shimizu, A; Arioka, Y; Kushima, I; Ozaki, N; Maruyama, S

NAGOYA JOURNAL OF MEDICAL SCIENCE Vol. 85 ( 4 ) page： 682 - 690 2023.11

Language：English Publisher：Nagoya Journal of Medical Science

The use of mesenchymal stem/stromal cells (MSCs) has attracted attention in the field of regenerative medicine based on their anti-inflammatory and tissue repair-promoting effects. Bone marrow is widely used as a source of MSCs; however, the performance of bone marrow (BM)-MSCs deteriorates as the cells age along with cell passaging. Recently, it has been reported that MSCs can be generated from induced pluripotent stem cells (iPSCs), which is expected to represent a new source of MSCs. However, few studies have investigated aging in iPSC-derived MSCs (iMSCs) and their functions. In this study, we investigated whether iMSCs overcome cellular senescence compared to that in BM-MSCs. Cellular senescence was quantitatively evaluated by staining iMSCs and BM-MSCs with fluorescein di-b-D-galactopyranoside (FDG) and following flow cytometer analysis. The hepatocyte growth factor (HGF) concentration in the culture supernatant was also measured as a factor in the therapeutic efficacy of nephritis. The iMSCs did not reach their proliferation limit and their morphology did not change even after 10 passages. The FDG positivity of BM-MSCs increased with passaging, whereas that in iMSCs did not increase. The HGF concentration increased with passaging in iMSCs. In conclusion, our results suggest that iMSCs may be less susceptible to senescence than BM-MSCs and may be used in clinical applications.

DOI： 10.18999/nagjms.85.4.682

生体腎移植後にCOVID-19に罹患し、遅発性に重症肺炎を合併した1例

COVID-19罹患後,遅発性に重症肺炎を合併した生体腎移植レシピエントの1例

田中章仁, 齋藤尚二, 古橋和拡, 安田宜成, 佐野優太, 加藤真史, 丸山彰一

日本腎臓学会誌 Vol. 65 ( 6-W ) page： 792 - 792 2023.9

田中章仁, 齋藤尚二, 古橋和拡, 安田宜成, 佐野優太, 加藤真史, 丸山彰一

移植 Vol. 58 ( 総会臨時 ) page： 270 - 270 2023.9

TOPICS 腎臓内科学脂肪由来間葉系幹細胞による重症腎炎改善メカニズムの解明 Invited

古橋和拡, 田中章仁, 丸山彰一

医学のあゆみ Vol. 285 ( 8 ) page： 755 - 756 2023.5

Prognosis and incidence of infections in chronic kidney disease patients with membranous nephropathy enrolled in a large Japanese clinical claims database Reviewed

Matsuzaki, T; Watanabe, Y; Tanaka, A; Furuhashi, K; Saito, S; Maruyama, S

BMC NEPHROLOGY Vol. 24 ( 1 ) page： 126 2023.5

Language：English Publisher：BMC Nephrology

Background: The treatment of membranous nephropathy involves a combination of conservative approaches, steroids, and immunosuppressive agents. Infection is an adverse effect of these treatments and its incidence is a critical issue for patients with membranous nephropathy, as many of them are older adults. However, the incidence of infections remains unclear; hence, this study investigated this issue using data from a large Japanese clinical claims database. Methods: From a database of patients with chronic kidney disease (n = 924,238), those diagnosed with membranous nephropathy from April 2008 to August 2021 with a history of one or more prescriptions and undergoing medical care were included. Patients who had undergone kidney replacement therapy were excluded. Patients were divided into three groups based on their prescriptions after diagnosis: prednisolone(PSL), who received steroids; PSL + IS, who were prescribed steroids and immunosuppressive agents; and C, who were treated without steroid or immunosuppressive agent use. The primary outcome was death or the initiation of kidney replacement therapy. The secondary outcome was death or hospitalization due to infection. Infectious diseases such as sepsis, pneumonia, urinary tract infections, cellulitis, cytomegalovirus infection, colitis, or hepatitis were defined as infections. Hazard ratios were expressed using group C as a reference. Results: Of 1,642 patients, the incidence of the primary outcome occurred in 62/460 individuals in the PSL group, 81/635 individuals in the PSL + IS group, and 47/547 individuals in the C group. The Kaplan–Meier survival curve showed no significant differences (P = 0.088). The incidence of secondary outcomes occurred in 80/460 individuals, 102/635 individuals, and 37/547 individuals in the PSL, PSL + IS, and C groups, respectively. The incidence of secondary outcomes was significantly higher in the PSL group (hazard ratio [HR] 2.43 [95% confidence interval [CI] 1.64–3.62, P < 0.01]) and PSL + IS group (HR 2.23 [95% CI 1.51–3.30, P < 0.01]). Conclusions: The outcome of membranous nephropathy was not completely satisfactory. Patients who use steroids and immunosuppressive agents have a high incidence of infection and may require close monitoring during the course of treatment.High-efficacy treatment with a low incidence of infections is desirable. The significance of this study lies in the fact that the impressions of membranous nephropathy, which have been recognized as tacit knowledge, were quantified using a clinical database.

DOI： 10.1186/s12882-023-03190-6

腎移植後患者におけるSARS-CoV-2 mRNAワクチン2回接種後から3回接種後までの抗体価の変化

藤枝久美子, 田中章仁, 菊地良介, 高井奈美, 齋藤尚二, 安田宜成, 藤田高史, 加藤真史, 古橋和拡, 丸山彰一

日本腎臓学会誌 Vol. 65 ( 3 ) page： 285 - 285 2023.5

腎移植後患者におけるSARS-CoV-2 mRNAワクチン2回接種後から3回接種後までの抗体価の変化

藤枝久美子, 田中章仁, 菊地良介, 高井奈美, 齋藤尚二, 安田宜成, 藤田高史, 加藤真史, 古橋和拡, 丸山彰一

日本腎臓学会誌 Vol. 65 ( 3 ) page： 285 - 285 2023.5

Long non-coding RNA lnc-CHAF1B-3 promotes renal interstitial fibrosis by regulating EMT-related genes in renal proximal tubular cells. Reviewed International journal

Kentaro Imai, Takuji Ishimoto, Tomohito Doke, Toshiki Tsuboi, Yu Watanabe, Keisuke Katsushima, Miho Suzuki, Hideto Oishi, Kazuhiro Furuhashi, Yasuhiko Ito, Yutaka Kondo, Shoichi Maruyama

Molecular therapy. Nucleic acids Vol. 31 page： 139 - 150 2023.3

Language：English Publishing type：Research paper (scientific journal)

Renal interstitial fibrosis (RIF) is a common pathological manifestation of chronic kidney diseases. Epithelial-mesenchymal transition (EMT) of tubular epithelial cells is considered a major cause of RIF. Although long non-coding RNAs (lncRNAs) are reportedly involved in various pathophysiological processes, the roles and underlying molecular mechanisms of lncRNAs in the progression of RIF are poorly understood. In this study, we investigated the function of lncRNAs in RIF. Microarray assays showed that expression of the lncRNA lnc-CHAF1B-3 (also called claudin 14 antisense RNA 1) was significantly upregulated in human renal proximal tubular cells by both transforming growth factor-β1 (TGF-β1) and hypoxic stimulation, accompanied with increased expression of EMT-related genes. Knockdown of lnc-CHAF1B-3 significantly suppressed TGF-β1-induced upregulated expression of collagen type I alpha 1, cadherin-2, plasminogen activator inhibitor-1, snail family transcriptional repressor I (SNAI1) and SNAI2. Quantitative reverse transcriptase PCR analyses of paraffin-embedded kidney biopsy samples from IgA nephropathy patients revealed lnc-CHAF1B-3 expression was correlated positively with urinary protein levels and correlated negatively with estimated glomerular filtration rate. In situ hybridization demonstrated that lnc-CHAF1B-3 is expressed only in proximal tubules. These findings suggest lnc-CHAF1B-3 affects the progression of RIF by regulating EMT-related signaling. Thus, lnc-CHAF1B-3 is a potential target in the treatment of RIF.

DOI： 10.1016/j.omtn.2022.12.011

Assessment of Antibody-Titer Changes after Second and Third Severe Acute Respiratory Syndrome Coronavirus 2 mRNA Vaccination in Japanese Post-Kidney-Transplant Patients Reviewed

Fujieda, K; Tanaka, A; Kikuchi, R; Takai, N; Saito, S; Yasuda, Y; Fujita, T; Kato, M; Furuhashi, K; Maruyama, S

VACCINES Vol. 11 ( 1 ) 2023.1

Language：English Publisher：Vaccines

Post-renal-transplant patients have a relatively low antibody-acquisition rate following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccination. In this study, antibody titers were measured 5–6 months and 3 weeks to 3 months after the second and third SARS-CoV-2 mRNA vaccinations, respectively. Post-renal-transplant patients visiting our hospital who had received three SARS-CoV-2 mRNA vaccine doses were included in the study. SARS-CoV-2 immunoglobulin G antibody titers were measured three times: between 3 weeks and 3 months after the second vaccination, 5–6 months after the second vaccination, and between 3 weeks and 3 months after the third vaccination. A total of 62 (40 men and 22 women) were included, 44 of whom (71.0%) were antibody positive after their third vaccination. On comparing the antibody-acquired and antibody-non-acquired groups, body mass index (BMI, odds ratio [OR]: 1.44, 95% confidence interval [CI]: 1.07–1.93, p < 0.05) and the estimated glomerular filtration rate (eGFR, OR: 1.14, 95% CI: 1.06–1.24, p < 0.01) were associated with antibody acquisition. Therefore, in Japanese post-kidney-transplant patients, increases in the antibody-acquisition rate and absolute antibody titer after the third vaccination were observed, with BMI and eGFR associated with the antibody-acquisition rate.

DOI： 10.3390/vaccines11010134

重症患者の免疫・血栓学的プロファイルの異質性に着目した持続的腎代替療法の回路早期閉塞発生メカニズムの探索

加藤孝昭, 沖尚弥, 春日井大介, 古橋和拡

日本透析医学会雑誌 Vol. 56 ( 6 ) page： 251 - 252 2023

Systematic characterization of seed overlap microRNA cotargeting associated with lupus pathogenesis. Reviewed International journal

Hiroki Kitai, Noritoshi Kato, Koichi Ogami, Shintaro Komatsu, Yu Watanabe, Seiko Yoshino, Eri Koshi, Shoma Tsubota, Yoshio Funahashi, Takahiro Maeda, Kazuhiro Furuhashi, Takuji Ishimoto, Tomoki Kosugi, Shoichi Maruyama, Kenji Kadomatsu, Hiroshi I Suzuki

BMC biology Vol. 20 ( 1 ) page： 248 - 248 2022.11

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: Combinatorial gene regulation by multiple microRNAs (miRNAs) is widespread and closely spaced target sites often act cooperatively to achieve stronger repression ("neighborhood" miRNA cotargeting). While miRNA cotarget sites are suggested to be more conserved and implicated in developmental control, the pathological significance of miRNA cotargeting remains elusive. RESULTS: Here, we report the pathogenic impacts of combinatorial miRNA regulation on inflammation in systemic lupus erythematosus (SLE). In the SLE mouse model, we identified the downregulation of two miRNAs, miR-128 and miR-148a, by TLR7 stimulation in plasmacytoid dendritic cells. Functional analyses using human cell lines demonstrated that miR-128 and miR-148a additively target KLF4 via extensively overlapping target sites ("seed overlap" miRNA cotargeting) and suppress the inflammatory responses. At the transcriptome level, "seed overlap" miRNA cotargeting increases susceptibility to downregulation by two miRNAs, consistent with additive but not cooperative recruitment of two miRNAs. Systematic characterization further revealed that extensive "seed overlap" is a prevalent feature among broadly conserved miRNAs. Highly conserved target sites of broadly conserved miRNAs are largely divided into two classes-those conserved among eutherian mammals and from human to Coelacanth, and the latter, including KLF4-cotargeting sites, has a stronger association with both "seed overlap" and "neighborhood" miRNA cotargeting. Furthermore, a deeply conserved miRNA target class has a higher probability of haplo-insufficient genes. CONCLUSIONS: Our study collectively suggests the complexity of distinct modes of miRNA cotargeting and the importance of their perturbations in human diseases.

DOI： 10.1186/s12915-022-01447-4

Influence of COVID-19 on the 10-year carbon footprint of the Nagoya University Hospital and medical research centre Reviewed

Morooka, H; Yamamoto, T; Tanaka, A; Furuhashi, K; Miyagawa, Y; Maruyama, S

GLOBALIZATION AND HEALTH Vol. 18 ( 1 ) page： 92 2022.11

Language：English Publisher：Globalization and Health

Background:: Amidst the climate crisis, a key goal of the medical sector is to reduce its large carbon footprint. Although the Coronavirus disease 2019 (COVID-19) pandemic greatly impacted the medical sector, its influence on carbon footprints remains unknown. Therefore, the aim of this study was to evaluate changes in the carbon footprint of a university hospital with a medical research centre over the past 10 years. Methods:: Data on electricity, gas, and water usage, pharmaceutical and medical supply costs, and waste amounts were recorded for Nagoya University Hospital from April 2010 to March 2021. The relevant emission factors were obtained from the Japanese government and the overall monthly carbon footprint was reported according to the Greenhouse Gas Protocol. The effect of the COVID-19 pandemic on the carbon footprint was then compared for three types of emission sources. Moreover, a regression model was used to plot quadratic functions as approximate functions using monthly carbon emissions and monthly average external temperatures. Finally, the monthly carbon footprint was calculated per hospital admission. Results:: The overall carbon footprint of the hospital was 73,546 tCO2e in 2020, revealing an increase of 26.60% over the last 10 years. Carbon emissions from electricity consumption represented 26% of total emissions. The individual carbon footprints of pharmaceuticals, medical supplies, waste, and water usage also increased from 2010 to 2020. The overall monthly carbon footprint was positively correlated with the average monthly temperature (R2 = 0.7566, p < 0.001). Compared with 2019, the overall carbon footprint decreased by 2.19% in 2020. Moreover, the monthly carbon footprint per hospital admission increased significantly between 2018 (0.24 tCO2e/admission) and 2020 (0.26 tCO2e/admission) (p = 0.002). Conclusion:: The overall carbon footprint of the hospital generally increased over the last decade. During the COVID-19 epidemic in 2020, the carbon footprint decreased slightly, likely because of the reduced number of patients. However, the carbon footprint per admission increased, which was attributed to more complicated patient backgrounds because of the ageing population. Therefore, evaluation of carbon emissions in the medical sector is urgently required in order to act on the climate crisis as soon as possible.

DOI： 10.1186/s12992-022-00883-9