Updated on 2025/03/18

写真a

 
HIRAIWA HIROAKI
 
Organization
Nagoya University Hospital Cardiology Assistant professor of hospital
Title
Assistant professor of hospital
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Degree 1

  1. 博士(医学) ( 2019.3   名古屋大学 ) 

Research Interests 4

  1. 心臓リハビリテーション

  2. 植込型左室補助人工心臓

  3. 体外式補助循環

  4. 重症心不全

Research Areas 1

  1. Life Science / Cardiology  / 臨床心不全

Research History 2

  1. Nagoya University   Department of Cardiology   Assistant professor of hospital

    2021.4

  2. Nagoya University   Department of Emergency and Critical Care Medicine   Assistant professor of hospital

    2019.4 - 2021.3

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    Country:Japan

Education 2

  1. Nagoya University   Graduate School of Medicine

    - 2019.3

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    Country: Japan

  2. Nagoya University   Graduate School of Medicine   Graduate School of Medicine

    - 2009.3

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    Country: Japan

Professional Memberships 10

  1. 日本移植学会

  2. 日本人工臓器学会

  3. 日本集中治療学会

  4. 日本心血管インターベンション治療学会

  5. 日本心臓リハビリテーション学会

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Papers 140

  1. Direct Visualization of External Outflow Graft Obstruction in Durable Left Ventricular Assist Device Using Transthoracic Echocardiography

    Shin Nagai, Shotaro Komeyama, Toru Kondo, Ryota Morimoto, Shingo Kazama, Hiroaki Hiraiwa, Takahiro Okumura, Tomo Yoshizumi, Masato Mutsuga, Toyoaki Murohara

    ASAIO Journal     2025.3

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

    DOI: 10.1097/MAT.0000000000002406

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  2. Usefulness of bicarbonate-based Impella purge solution in a patient with heparin-induced thrombocytopenia: the first case report of long-term management in Japan. Open Access

    Shin Nagai, Hiroaki Hiraiwa, Ryota Ito, Yuichiro Koyama, Kiyota Kondo, Shingo Kazama, Toru Kondo, Ryota Morimoto, Takahiro Okumura, Hideki Ito, Tomo Yoshizumi, Masato Mutsuga, Toyoaki Murohara

    Journal of artificial organs : the official journal of the Japanese Society for Artificial Organs   Vol. 28 ( 1 ) page: 83 - 89   2025.3

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

    Percutaneous mechanical circulatory support utilizing micro-axial flow pumps, such as the Impella group of devices, has become a life-saving technique in the treatment of refractory cardiogenic shock, with ever-increasing success rates. A 30-year-old man presented with acute decompensated heart failure and a severely reduced left ventricular ejection fraction (17%). Despite initial treatment with inotropic drugs and intra-aortic balloon pump support, his hemodynamic status remained unstable. Transition to Impella CP mechanical circulatory support was made on day 6 owing to persistently low systolic blood pressure. A significant decline in platelet count prompted suspicion of heparin-induced thrombocytopenia (HIT), later confirmed by positive platelet-activated anti-platelet factor 4/heparin antibody and a 4Ts score of 6 points. Argatroban was initially used as the purge solution, but owing to complications, a switch to Impella 5.0 and a bicarbonate-based purge solution (BBPS) was performed. Despite additional veno-arterial extracorporeal membrane oxygenation support on day 24, the patient, aiming for ventricular assist device treatment and heart transplantation, died from infection and multiple organ failure. Remarkably, the Impella CP continued functioning normally until the patient's demise, indicating stable Impella pump performance using BBPS. This case highlights the usefulness of BBPS as an alternative to conventional Impella heparin purge solution when HIT occurs.

    DOI: 10.1007/s10047-024-01452-0

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  3. Ability of dynamic chest radiography to identify left ventricular systolic dysfunction in heart failure. International journal

    Hiroaki Hiraiwa, Shin Nagai, Ryota Ito, Kiyota Kondo, Shingo Kazama, Toru Kondo, Shiro Adachi, Kenji Furusawa, Akihito Tanaka, Ryota Morimoto, Takahiro Okumura, Toyoaki Murohara

    The international journal of cardiovascular imaging   Vol. 41 ( 3 ) page: 507 - 521   2025.3

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    Dynamic chest radiography (DCR) can estimate haemodynamic parameters in heart failure (HF). However, no studies have evaluated its ability to determine cardiac systolic function in HF. This experimental study investigates the correlation between left ventricular (LV) ejection fraction (LVEF) and DCR image parameters in HF. Ninety-one patients with acute HF (median age, 58 years; males, 75%) (cardiologist diagnosis using the Framingham criteria) underwent DCR and transthoracic echocardiography after treatment for the uncompensated phase of HF. The LV apex pixel value (PV) change was measured by DCR. Correlations between the PV change and LVEF, as well as sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of DCR, were evaluated. LVEF and LV apex PV change were correlated in all patients (R = 0.428, P < 0.001) and in patients with LVEF < 50% (n = 38; R = 0.355, P = 0.029), < 40% (n = 31; R = 0.343, P = 0.059), and < 30% (n = 23; R = 0.321, P = 0.135). There was no significant correlation for patients with LVEF ≥ 50% (n = 53; R = - 0.004, P = 0.980). The LV apex PV change rate cutoff values for identifying LVEF < 50%, < 40%, and < 30% were 9.3% (AUC: 0.761, sensitivity: 0.698, specificity: 0.789, P < 0.001), 5.5% (AUC: 0.765, sensitivity: 0.883, specificity: 0.645, P < 0.001), and 5.5% (AUC: 0.767, sensitivity: 0.838, specificity: 0.696, P < 0.001), respectively. DCR may be useful to identify LV systolic dysfunction based on LVEF in acute HF.

    DOI: 10.1007/s10554-025-03332-x

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  4. Preliminary Efficacy and Safety Analysis of Tafamidis in Post-Liver Transplant Patients with Hereditary Transthyretin Cardiac Amyloidosis. International journal

    Takahiro Okumura, Kenji Furusawa, Ryota Ito, Hiroaki Hiraiwa, Toyoaki Murohara

    Archives of medical research   Vol. 56 ( 1 ) page: 103083 - 103083   2025.1

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    Hereditary transthyretin cardiac amyloidosis (ATTRv-CA) after liver transplantation remains challenging to treat due to residual amyloid deposits in extrahepatic organs, including the heart. Tafamidis, a transthyretin tetramer stabilizer, has shown promise in the treatment of ATTRv-CA; however, its efficacy and safety after liver transplantation are uncertain. In this preliminary retrospective review, we assessed the efficacy and safety of tafamidis (80 mg) in three ATTRv-CA cases after liver transplantation. Following one year of treatment, all patients experienced improvement in dyspnea, New York Heart Association functional class, brain natriuretic peptide levels, and cardiac troponin T levels. No significant changes in echocardiographic parameters were observed. Notably, no cardiovascular or drug-related adverse events occurred during treatment. Our findings suggest that tafamidis may benefit post-liver transplant patients with ATTRv-CA and warrant further investigation through randomized controlled trials with larger cohorts. This study highlights a potential therapeutic avenue for the management of cardiovascular involvement in this challenging patient population.

    DOI: 10.1016/j.arcmed.2024.103083

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  5. Predicting survival after Impella implantation in patients with cardiogenic shock: The J-PVAD risk score. International journal Open Access

    Toru Kondo, Tomo Yoshizumi, Ryota Morimoto, Takahiro Imaizumi, Shingo Kazama, Hiroaki Hiraiwa, Takahiro Okumura, Toyoaki Murohara, Masato Mutsuga

    European journal of heart failure   Vol. 27 ( 1 ) page: 51 - 59   2025.1

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    AIMS: Impella has become a new option for mechanical circulatory support in patients with cardiogenic shock (CS); however, prognostic models for patients after Impella are lacking. We aimed to identify the factors that predict in-hospital mortality in patients with CS requiring Impella and develop a new risk prediction model. METHODS AND RESULTS: We utilized the J-PVAD registry, which includes all cases where Impella was implanted in Japan. Two-thirds of the patients in the J-PVAD registry were randomly assigned to the derivation cohort (n = 1701), and the other third was assigned to the validation cohort (n = 850). A backward stepwise logistic regression model was developed to identify factors associated with in-hospital mortality. In the derivation cohort, 956 patients were discharged alive, and 745 patients (43.8%) died during hospitalization. Among 29 candidate variables, 12 were independently associated with in-hospital mortality and were applied as components of the risk model, including age, sex, body mass index, fulminant myocarditis aetiology, cardiac arrest in hospital, baseline veno-arterial extracorporeal membrane oxygenation use, mean arterial pressure, lactate, lactate dehydrogenase, total bilirubin, creatinine, and albumin levels. The comparison of predicted and observed in-hospital mortality according to the 7th quantiles using the J-PVAD risk score showed good calibration. The area under the curve for the J-PVAD risk score was 0.76 (95% confidence interval 0.73-0.78). In the validation cohort, the J-PVAD risk score showed good calibration and discrimination ability. CONCLUSIONS: The J-PVAD risk score can be calculated using variables easily obtained in routine clinical practice. It helps the accurate stratification of mortality risk and facilitates clinical decision-making.

    DOI: 10.1002/ejhf.3471

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Books 1

  1. 特集 エキスパートに学ぶ 最新の循環器治療薬の使い方 知っておくべき10種類の循環器治療薬と治療法 心不全に対する新規治療薬 4-HCNチャネル遮断薬 コララン Reviewed

    奥村 貴裕, 荒木 孝, 平岩 宏章( Role: Joint author)

    medicina  2021.1 

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    Language:Japanese Book type:Textbook, survey, introduction

    DOI: 10.11477/mf.1402227378

MISC 18

  1. Dilated cardiomyopathy with anti-mitochondrial M2 antibody: A case series.

    Kazama S, Kondo T, Ito R, Kimura Y, Kuwayama T, Hiraiwa H, Morimoto R, Okumura T, Murohara T

    Journal of cardiology cases   Vol. 28 ( 1 ) page: 11 - 15   2023.7

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    Language:English   Publisher:Journal of Cardiology Cases  

    Patients with dilated cardiomyopathy (DCM) sometimes show anti-mitochondrial M2 antibody (AMA-M2) positivity. We aimed to compare the characteristics of DCM cases with and without AMA-M2, and to describe cases of DCM with AMA-M2 positivity. A total of 84 patients with DCM were analyzed. Six patients (7.1 %) were positive for AMA-M2. Of these six patients, five (83.3 %) had primary biliary cirrhosis (PBC) and four (66.7 %) had myositis. Patients with AMA-M2 positivity had more atrial fibrillation and more premature ventricular contractions than those without. Left and right atrial longitudinal dimensions were larger in patients with AMA positivity (left atrium, 65.9 mm vs. 54.7 mm, p = 0.02; right atrium, 57.0 mm vs. 46.1 mm, p = 0.02). Of the six patients with AMA-M2 positivity, three underwent cardiac resynchronization therapy with defibrillator implantation and three required catheter ablation treatment. Steroids were used in three patients. One patient died of unresolved lethal arrhythmia and another required re-hospitalization for heart failure; the remaining four patients did not have adverse events. Patients with DCM with AMA-M2 positivity had a higher affinity for PBC and myositis than those without, and are characterized by atrial enlargement and arrhythmias. Learning objective: Patients with dilated cardiomyopathy sometimes exhibit anti-mitochondrial M2 antibody positivity. These patients are at higher risk for primary biliary cirrhosis and inflammatory myositis, and their cardiac disorders are characterized by atrial enlargement and various arrhythmias. The course of the disease up to the time of diagnosis and after steroid use varies, and the prognosis is poor in advanced cases.

    DOI: 10.1016/j.jccase.2023.02.021

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  2. Contractile pericarditis-like hemodynamics in dilated-phase hypertrophic cardiomyopathy with giant atrium.

    Morimoto R, Ito R, Araki T, Mizutani T, Kimura Y, Kazama S, Oishi H, Kuwayama T, Sugiura Y, Hiraiwa H, Kondo T, Okumura T, Kobayashi K, Mutsuga M, Murohara T

    Journal of cardiology cases   Vol. 27 ( 5 ) page: 199 - 202   2023.5

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    A 47-year-old man with dilated-phase hypertrophic cardiomyopathy was admitted to the hospital with worsening heart failure. As the enlarged atrium caused a constrictive pericarditis-like hemodynamic condition, atrial wall resection and tricuspid valvuloplasty were performed. Postoperatively, pulmonary artery pressure rose due to increased preload; however, the rise in pulmonary artery wedge pressure was restrained, and the cardiac output significantly improved. When the pericardium is extremely stretched due to atrial enlargement, it can lead to an elevation of intrapericardial pressure, and both atrial volume reduction and tricuspid valve plasty could lead to increased compliance and contribute to hemodynamic improvement. Learning objective: Atrial wall resection for massive atrial enlargement and tricuspid annuloplasty in patients with diastolic-phase hypertrophic cardiomyopathy effectively relieves unstable hemodynamics.

    DOI: 10.1016/j.jccase.2023.01.005

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  3. Cardiac Rehabilitation in Severe Heart Failure Patients with Impella 5.0 Support via the Subclavian Artery Approach Prior to Left Ventricular Assist Device Implantation.

    Shimizu M, Hiraiwa H, Tanaka S, Tsuchikawa Y, Ito R, Kazama S, Kimura Y, Araki T, Mizutani T, Oishi H, Kuwayama T, Kondo T, Morimoto R, Okumura T, Ito H, Yoshizumi T, Mutsuga M, Usui A, Murohara T

    Journal of personalized medicine   Vol. 13 ( 4 )   2023.4

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    Impella 5.0 circulatory support via subclavian artery (SA) access may be a safe approach for patients undergoing cardiac rehabilitation (CR). In this case series, we retrospectively analyzed the demographic characteristics, physical function, and CR data of six patients who underwent Impella 5.0 implantation via the SA prior to left ventricular assist device (LVAD) implantation between October 2013 and June 2021. The median age was 48 years, and one patient was female. Grip strength was maintained or increased in all patients before LVAD implantation (pre-LVAD) compared to after Impella 5.0 implantation. The pre-LVAD knee extension isometric strength (KEIS) was less than 0.46 kgf/kg in two patients and more than 0.46 kgf/kg in three patients (unavailable KEIS data, n = 1). With Impella 5.0 implantation, two patients could ambulate, one could stand, two could sit on the edge of the bed, and one remained in bed. One patient lost consciousness during CR due to decreased Impella flow. There were no other serious adverse events. Impella 5.0 implantation via the SA allows mobilization, including ambulation, prior to LVAD implantation, and CR can be performed relatively safely.

    DOI: 10.3390/jpm13040630

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  4. A Case of Systemic Capillary Leak Syndrome With Severe Cardiac Dysfunction After mRNA Vaccination for COVID-19.

    Araki T, Morimoto R, Ito R, Mizutani T, Kimura Y, Kazama S, Oishi H, Kuwayama T, Hiraiwa H, Kondo T, Okumura T, Murohara T

    CJC open   Vol. 4 ( 7 ) page: 656 - 659   2022.7

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    A 53-year-old woman with no significant medical history developed cardiogenic shock 4 days after receiving the second dose of the COVID-19 mRNA vaccine (BNT162b2, Pfizer/BioNtech). The patient required extracorporeal membrane oxygenation and an Impella device. Based on significant hemoconcentration, decreased plasma protein levels, and pathologic findings in myocardial specimens, the patient was diagnosed with vaccination-induced fulminant systemic capillary leak syndrome (SCLS) with severe cardiac dysfunction. This case highlights that SCLS can occur after COVID-19 mRNA vaccination and may be associated with cardiac dysfunction. In patients with cardiogenic shock, hemoconcentration, and hypoalbuminemia after vaccination, SCLS should be considered.

    DOI: 10.1016/j.cjco.2022.03.008

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  5. Recurrent fulminant non-rheumatic streptococcal myocarditis proven by endomyocardial biopsy and autopsy.

    Hiraiwa H, Morimoto R, Ando R, Ito R, Araki T, Mizutani T, Kazama S, Kimura Y, Oishi H, Kuwayama T, Yamaguchi S, Kondo T, Okumura T, Enomoto A, Murohara T

    Journal of cardiology cases   Vol. 26 ( 1 ) page: 62 - 65   2022.7

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    A 42-year-old man with a history of acute myocarditis after streptococcal pharyngitis developed recurrent fulminant myocarditis. Endomyocardial biopsy revealed myocyte degeneration, interstitial edema, and neutrophil infiltration. The patient's cardiac function deteriorated rapidly, and he died despite mechanical circulatory support. Autopsy revealed neutrophil infiltration, interstitial edema, and micro-abscesses containing masses of streptococci and neutrophilic phagocytosis within the myocardium. The patient did not meet the diagnostic criteria for acute rheumatic fever; thus, he was diagnosed with non-rheumatic streptococcal myocarditis. Non-rheumatic streptococcal myocarditis rarely recurs, but it can be fulminant upon recurrence. Learning objective: We report a rare case of recurrent fulminant non-rheumatic streptococcal myocarditis. Endomyocardial biopsy and autopsy revealed neutrophil infiltration and micro-abscesses containing bacterial masses of streptococci and neutrophilic phagocytosis in the myocardium. The patient did not meet the diagnostic criteria for acute rheumatic fever; thus, he was diagnosed with non-rheumatic streptococcal myocarditis. Non-rheumatic streptococcal myocarditis rarely recurs, but it can be fulminant upon recurrence.

    DOI: 10.1016/j.jccase.2022.02.004

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KAKENHI (Grants-in-Aid for Scientific Research) 2

  1. 心脾連関に注目した新しい心不全治療法の開発

    Grant number:21K16085  2021.4 - 2026.3

    日本学術振興会  科学研究費助成事業  若手研究

    平岩 宏章

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    Authorship:Principal investigator 

    Grant amount:\4680000 ( Direct Cost: \3600000 、 Indirect Cost:\1080000 )

    心不全は未だ致死的な疾患の一つであり、個別化医療を含めた新規治療法の開発の社会的ニーズは非常に高い。
    近年、心不全において心臓と他臓器の連関が注目されているが、脾臓との連関(心脾連関)については未解明の部分が多い。一方、脾臓には様々な役割があるが、組織マクロファージを介した心脾連関に注目した先行研究はない。また、心不全における脾臓の生理学的な役割も十分解明されていない。
    本研究は、心不全における多臓器連関の中での脾臓の機能多様性や、病態との関連を明らかにし、さらには、心不全における新たなバイオマーカやモニタリングの開発や、心脾連関への介入を念頭においた新規の心不全治療法の開発を目指した研究である。
    本研究は、心不全における脾臓の未解明の役割、特に多臓器連関の中での脾臓の機能多様性を探索し検証することを目的としている。これまでに研究代表者は、左室補助人工心臓(LVAD)を要する重症心不全で、脾臓容積は増大し、LVAD不良による心不全増悪に伴い脾臓容積は速やかに減少することを報告し、重症心不全において脾臓は有効循環血漿量を調節している可能性を示した。また、脾臓容積はLVAD装着患者の拍出指数(Pulsatility Index)と関連し、自己心拍出量に寄与している可能性を示した。さらに、脾臓容積と運動耐容能の関連について検討した。運動耐容能指標である最高酸素摂取量(PeakVO2)に影響を与える因子の相関・因果関係を共分散構造解析(SEM)を用いて検討し、脾臓容積はLVAD装着患者の血中ヘモグロビンを介して、PeakVO2と関連することを示した。また、慢性心不全患者219人のデータを後ろ向きに解析し、脾臓容積と予後の関連について検討した。 患者集団は、年齢54歳、男性66%、NYHA3が9%、LVEF42%であった(中央値)。主要アウトカムは、複合心臓イベント(心臓死および心不全増悪入院)とした。結果、脾臓容積の中央値は、118.0mLであり。脾臓容積指数(SVI)は心拍出量および一回心拍出量と正の相関を示し、全身血管抵抗とは負の相関を示した。心イベント予測のための最適なSVIのカットオフ値は68.9 mL/m2であり、低SVI 群は高SVI群よりも、心イベントが多かった。ここまでのまとめとして、The cardiosplenic axis: the prognostic role of the spleen in heart failure と題したReview論文を報告した。現在、心不全における脾臓での髄外造血に注目した心臓、脾臓、骨髄の臓器連関について、検証中である。
    これまでに、心不全患者における脾臓容積と血行動態、運動耐容能、予後との関係を、臨床データを用いて検討した。その結果、特に心不全においては神経体液性因子および交感神経活動の活性化に伴い、その大きさを変化させ、構造的リモデリングを生じ、有効循環血漿量を調節している可能性が示唆された。すなわち心脾連関において、マクロの視点から脾臓の役割の一部を明らかにした。さらには、文献的考察から、脾臓から動員される免疫細胞やマクロファージが、心筋組織へ影響を与えることを示し、脾臓の機能的リモデリングの側面と合わせて、心脾連関の全体の概要についてレビューを行った。
    今後の研究内容として、引き続きミクロの視点から心脾連関のメカニズムについて検討する方針である。構造的リモデリングを生じた脾臓は機能的リモデリングを来し、脾臓からマクロファージや単球などの免疫細胞が血液中に放出される。脾臓由来の免疫細胞は、心臓に対して、心保護的な作用と逆の作用の両方を示す可能性がある。例えば、心臓固有のマクロファージと脾臓由来のマクロファージのバランスが心不全における慢性炎症の持続や線維化に影響を及ぼしている可能性がある。これらのメカニズムを、動物モデルを用いて検討していく予定である。さらには、近年、クローン性造血が心不全をはじめとする心血管疾患発症の病態に関与していることが報告されている。クローン性造血は、心筋の線維化を引き起こし、駆出率が維持された心不全(HFpEF)の病態を生じうる。HFpEFは高齢化と関連しているが、HFpEFに対する治療法はほとんど進歩していないのが現状である。このため、HFpEFにおける心臓、脾臓、さらには骨髄の臓器連関の概念について、免疫細胞の関与も含む髄外造血に焦点を当て、検証していく。また、脾臓がHFpEFの新たな治療ターゲットとなり得るかどうかも検証していく。

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  2. Development of novel treatment for fulminant myocarditis focusing on immune checkpoint molecules

    Grant number:19K23843  2019.8 - 2023.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Research Activity Start-up

    Hiraiwa Hiroaki

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    Authorship:Principal investigator 

    Grant amount:\1430000 ( Direct Cost: \1100000 、 Indirect Cost:\330000 )

    This study investigated the relationship between T cell markers and PD-L1 expression in myocardial tissue and the prognosis of patients with fulminant lymphocytic myocarditis (FM). We analyzed 16 FM patients and found that the number of CD8+ T cells and CD8+/CD4+ T cell ratio were significantly higher in the group with cardiac events (composite of cardiac death and left ventricular assist device implantation). Additionally, the number of FoxP3+ T cells was higher in the cardiac event group, and PD-L1 expression in myocardial cells was also higher in the same group. Kaplan-Meier survival analysis revealed that high CD8+ T cell count or high PD-L1 expression in the myocardium could be poor prognostic factors in FM. Combining the expression of CD8+ T cells and PD-L1 could potentially help stratify the risk of cardiac events in FM. This study provides new insights into the mechanism and prognosis of fatal FM, which could aid in the development of new treatment strategies in the future.

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