IL-6/gp130 signaling in CD4+ T cells drives the pathogenesis of pulmonary hypertension.

Pulmonary arterial hypertension (PAH) is characterized by stenosis and occlusions of small pulmonary arteries, leading to elevated pulmonary arterial pressure and right heart failure. Although accumulating evidence shows the importance of interleukin (IL)-6 in the pathogenesis of PAH, the target cells of IL-6 are poorly understood. Using mice harboring the floxed allele of gp130, a subunit of the IL-6 receptor, we found substantial Cre recombination in all hematopoietic cell lineages from the primitive hematopoietic stem cell level in SM22α-Cre mice. We also revealed that a CD4+ cell-specific gp130 deletion ameliorated the phenotype of hypoxia-induced pulmonary hypertension in mice. Disruption of IL-6 signaling via deletion of gp130 in CD4+ T cells inhibited phosphorylation of signal transducer and activator of transcription 3 (STAT3) and suppressed the hypoxia-induced increase in T helper 17 cells. To further examine the role of IL-6/gp130 signaling in more severe PH models, we developed Il6 knockout (KO) rats using the CRISPR/Cas9 system and showed that IL-6 deficiency could improve the pathophysiology in hypoxia-, monocrotaline-, and Sugen5416/hypoxia (SuHx)-induced rat PH models. Phosphorylation of STAT3 in CD4+ cells was also observed around the vascular lesions in the lungs of the SuHx rat model, but not in Il6 KO rats. Blockade of IL-6 signaling had an additive effect on conventional PAH therapeutics, such as endothelin receptor antagonist (macitentan) and soluble guanylyl cyclase stimulator (BAY41-2272). These findings suggest that IL-6/gp130 signaling in CD4+ cells plays a critical role in the pathogenesis of PAH.

Can right ventricular endomyocardial biopsy predict left ventricular fibrosis beforehand in dilated cardiomyopathy?

AIMS: Myocardial fibrosis of the left ventricle (LV) is a prognostic factor in dilated cardiomyopathy (DCM). This study aims to evaluate whether fibrosis of right ventricular (RV) endomyocardial biopsy (EMB) can predict the degree of LV fibrosis beforehand in DCM. METHODS AND RESULTS: Fibrosis extent in 70 RV-EMB specimens of DCM diagnosis was compared with that in the whole cross-sectional LV of excised hearts in the same patients (52 explanted hearts for transplant and 18 autopsied hearts). The median interval between biopsy and excision was 4.1 (0.13-19.3) years. The fibrosis area ratio of the EMBs and excised hearts were evaluated via image analysis. The distribution of cardiovascular magnetic resonance-late gadolinium enhancement (LGE) in the intraventricular septum was classified into four quartile categories. The fibrosis area ratio in RV-EMB correlated significantly with that in the short-axis cut of the LV of excised hearts (r = 0.82, P < 0.0001) and with a diffuse pattern of LGE (r = 0.71, P = 0.003). In a multivariate model, after adjusting for the interval between biopsy performance and heart excision, the fibrosis area ratio in RV-EMB was associated with that in LV-excised heart (regression coefficient, 0.82; 95% confidence interval, 0.68-0.95; P < 0.0001). CONCLUSIONS: The fibrosis observed in RV-EMB positively correlated with the extent of fibrosis in the LV of excised hearts in patients with DCM. The study findings may help predict LV fibrosis, considered a prognostic factor of DCM through relatively accessible biopsy techniques.

Tenascin-C as a potential marker for immunohistopathology of doxorubicin-induced cardiomyopathy.

Aims: Doxorubicin is used in classical chemotherapy for several cancer types. Doxorubicin-induced cardiomyopathy (DOX-CM) is a critical issue among cancer patients. However, differentiating the diagnosis of DOX-CM from that of other cardiomyopathies is difficult. Therefore, in this study, we aimed to determine novel histopathological characteristics to diagnose DOX-CM. Methods and results: Twelve consecutive patients with DOX-CM who underwent cardiac histopathological examination in two medical centres were included. Twelve patients with dilated cardiomyopathy, who were matched with DOX-CM patients in terms of age, sex, and left ventricular ejection fraction, formed the control group. Another control group comprised five consecutive patients with cancer therapy-related cardiac dysfunction induced by tyrosine kinase inhibitors or vascular endothelial growth factor inhibitors were the controls. The positive area of tenascin-C, number of infiltrating macrophages, and presence of p62- and ubiquitin-positive cardiomyocytes were evaluated. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were used for in vitro investigation. The myocardium exhibited significantly greater tenascin-C-positive area and macrophage number in the DOX-CM group than in the control groups (P < 0.01). The tenascin-C-positive area correlated with the number of both CD68- and CD163-positive cells (r = 0.748 and r = 0.656, respectively). Immunostaining for p62 was positive in 10 (83%) patients with DOX-CM. Furthermore, western blotting analysis revealed significant increase in tenascin-C levels in hiPSC-CMs upon doxorubicin treatment (P < 0.05). Conclusion: The combined histopathological assessment for tenascin-C, macrophages, and p62/ubiquitin may serve as a novel tool for the diagnosis of DOX-CM. Doxorubicin may directly affect the expression of tenascin-C in the myocardium.

A 5-year survivor of endarterectomy for sclerosing undifferentiated intimal sarcoma of the pulmonary artery: Importance of clinical suspicion and careful histologic evaluation.

We present a diagnostically challenging case of intimal sarcoma of the pulmonary artery (PA) due to the histologic finding of a sclerosing appearance with no appreciable spindle/pleomorphic cell proliferation. Initial endarterectomy specimens were composed of sclerosing extracellular matrix with a few bland cells, some recanalization, and fibrin thrombi, impeding the confirmation of intimal sarcoma as these findings were also consistent with chronic thromboembolic pulmonary hypertension. However, the patient experienced recurrence 5 years later, and the second endarterectomy specimens revealed more firm and solid mass and the proliferation of atypical spindle/pleomorphic cells within a myxomatous matrix in the distal PA, leading to the definitive diagnosis of undifferentiated intimal sarcoma of the PA. The archival specimens from the endarterectomy confirmed intense MDM2 expression by immunohistochemistry, suggesting its role as a potential diagnostic marker for intimal sarcoma. This case highlights that prominent sclerosing extracellular matrix with very few atypical cells should raise the possibility of intimal sarcoma of the PA and that high index of suspicion, generous sampling, and ancillary tests are critical for accurate diagnosis. In this case, the tumor was incidentally removed by endarterectomy, resulting in 5 years of survival.

Pulmonary veno-occlusive disease after respiratory syncytial virus infection in a post hematopoietic stem cell transplantation patient.

Background: Pulmonary veno-occlusive disease (PVOD) is a rare but fatal complication of hematopoietic stem cell transplantation (HSCT). Although literature on PVOD post-HSCT is scarce, a recent study has indicated that this condition may be underestimated. Respiratory syncytial virus (RSV) is a common respiratory pathogen that causes common cold in healthy individuals but may lead to severe lower respiratory infection accompanied by respiratory distress in infants and immunocompromised individuals, such as post-HSCT patients. However, little is known about the relationship between PVOD and RSV infections. Case report: A 4-year-old boy was diagnosed with metastatic neuroblastoma and underwent intensive chemotherapy, autologous HSCT, and allogeneic cord blood transplantation (CBT). He experienced PVOD on day 194 following CBT after displaying upper respiratory symptoms and positive RSV antigen test results approximately one month prior. Pathological examination of a lung biopsy specimen revealed lung injury suspected to be associated with viral infection in addition to PVOD-related findings, suggesting that RSV infection might have contributed to the onset of PVOD. Conclusions: The patient's clinical history and histological findings indicated that RSV could have triggered the development of PVOD under potential endothelial damage caused by HSCT and other prior treatments. Common respiratory viral infections, such as RSV infection, may evoke the development of PVOD.

Transthyretin derived amyloid deposits in the atrium and the aortic valve: insights from multimodality evaluations and mid-term follow up.

BACKGROUND: Recent studies have reported atrial involvement and coexistence of aortic stenosis in transthyretin (ATTR) cardiac amyloidosis (CA). However, pathological reports of extraventricular ATTR amyloid deposits in atrial structures or heart valves are limited, and the clinical implications of ATTR amyloid deposits outside the ventricles are not fully elucidated. CASE PRESENTATION: We report 3 cases of extraventricular ATTR amyloid deposits confirmed in surgically resected aortic valves and left atrial structures, all of which were unlikely to have significant ATTR amyloidosis infiltrating the ventricles as determined by multimodality evaluation including 99mtechnetium-pyrophosphate scintigraphy, cardiac magnetic resonance, endomyocardial biopsy and their mid-term clinical course up to 5 years. These findings suggested that these were extraventricular ATTR amyloid deposits localized in the aortic valve and the left atrium. CONCLUSIONS: While long-term observation is required to fully clarify whether these extraventricular ATTR amyloid deposits are truly localized outside the ventricles or are early stages of ATTR-CA infiltrating the ventricles, our 3 cases with multimodality evaluations and mid-term follow up suggest the existence of extraventricular ATTR amyloid deposits localized in the aortic valve and left atrial structures.

COVID-19-associated myocardial injury: A case report.

Coronavirus disease 2019 (COVID-19) is often accompanied by pneumonia and can be fatal. We report a case of COVID-19-associated myocardial injury mimicking fulminant myocarditis. Endomyocardial biopsy revealed numerous von Willebrand factor-rich microthrombi with small myocardial necrotic areas, complement deposits in small vessels/microthrombi, and macrophage-predominant interstitial infiltration. These findings, distinct from those of typical lymphocytic myocarditis, show diffuse endothelial injury, complement activation, and activated macrophages as characteristic features of COVID-19-associated pathogenesis. Dysregulated serum cytokine profiles predicting severe/critical COVID-19-associated myocardial injury were also determined. This case emphasizes the occurrence of fatal cardiac manifestation with microthrombotic injury in the early stage of COVID-19.

Multimodality assessments of wild-type transthyretin cardiac amyloidosis with no ventricular hypertrophy.

While patients with transthyretin cardiac amyloidosis (ATTR-CA) typically present with concentric or asymmetric hypertrophy, a small percentage of ATTR-CA is known to present with 'atypical' cardiac morphologies such as eccentric hypertrophy or even no hypertrophy. However, detailed report of multimodality assessments of ATTR-CA with no ventricular hypertrophy is lacking. Herein, we report detailed multimodality assessments of an 81-year-old Japanese woman with heart failure and history of carpal tunnel syndrome and lumbar canal stenosis, presenting no ventricular hypertrophy and negative 99m technetium-pyrophosphate scintigraphy, who was eventually diagnosed as having wild-type ATTR-CA. Our case highlights the role of multimodality assessments for early diagnosis of ATTR-CA in patients with atypical cardiac morphologies and also emphasizes the limitations of bone scintigraphy and the importance of considering ATTR-CA in patients with non-cardiac manifestations of ATTR amyloidosis.

Early vascular responses to abluminal biodegradable polymer-coated versus circumferential durable polymer-coated newer-generation drug-eluting stents in humans: a pathological study.

BACKGROUND: Recent clinical studies are testing strategies for short (1-3 months) dual antiplatelet therapy following newer-generation drug-eluting stent (DES) placement. However, detailed biological responses to newer-generation DES remain unknown in humans. AIMS: We sought to evaluate early pathologic responses to abluminal biodegradable polymer-coated (BP-) DES compared with circumferential durable polymer-coated (DP-) DES in human autopsy cases. METHODS: The study included 38 coronary lesions with newer-generation DES implanted for <90 days (DP-DES=24, BP-DES=14) in 26 autopsy cases. The degree of strut coverage was defined as follows: grade 0 (bare), grade 1 (with fibrin or tissues/cells without endothelium), grade 2 (with single-layered endothelium), and grade 3 (with endothelium and underlying smooth muscle cell layers). RESULTS:  The duration following implantation was similar in DP- and BP-DES (median=20 vs 17 days). A total of 2,022 struts (DP-DES=1,297, BP-DES=725) were pathologically analysed. Focal grade 2 coverage was observed as early as 5 days after the implantation in both stents. The multilevel mixed-effects ordered logistic regression model demonstrated that BP-DES exhibited greater strut coverage compared with DP-DES (odds ratio [OR]: 3.64, 95% confidence interval [CI]: 1.37-9.67; p=0.009), which remained significant after adjustment for the duration following implantation and underlying tissue characteristics (OR: 2.74, 95% CI: 1.10-6.80; p=0.030). The predictive probability of grade 2 and 3 coverage was comparably limited at 30 days (DP-DES=17.1%, BP-DES=28.7%) and increased at 90 days (DP-DES=76.5%, BP-DES=86.6%). Both stents showed low inflammation and a similar degree of fibrin deposition. CONCLUSIONS: Single-layered endothelial coverage begins in the days after newer-generation DES placement, and BP-DES potentially exhibit faster strut coverage with smooth muscle cell infiltration than DP-DES in humans. Nevertheless, vessel healing remains suboptimal in both stents at 30 days.

Morphological characteristics of cardiac myxoma causing embolism: a series of 40 years of experience at a single institute.

Systemic and cerebral embolisms are serious complications of associated with cardiac myxoma. Embolism risk reportedly depends on the gross and histological morphology. This study is aimed at analyzing the morphologic pattern of excised cardiac myxoma as a high-risk embolic cause. Between 1978 and April 2022, 116 surgical specimens of cardiac myxomas were recorded at the pathology department of our hospital. The tumors were classified into three types based on their macroscopic shapes and external morphology-round-smooth, irregular, and villous-to investigate the embolic complications. Of the 116 specimens, 106 macroscopic images of cardiac myxoma (89% were located in the left atrium) were prepared. Round-smooth types were found in 36 (34.0%) patients, irregular types in 32 (30.2%) patients, and the villous types in 38 (35.8%) patients. Multivariable analysis revealed that a villous external appearance was an independent predictor of embolic events (odds ratio: 8.7; 95% confidence interval: 2.4-42.1; p < 0.001). Villous external appearance of cardiac myxoma was associated with the highest risk of distal embolism.

A Case of Lung Cancer with Very-Late-Onset Immune Checkpoint Inhibitor-Related Myocarditis.

Immune checkpoint inhibitor (ICI)-related myocarditis has been reported to appear in the early phase after ICI initiation. Herein, we report the case of a 78-year-old man with non-small cell lung cancer. Pembrolizumab was introduced as first-line therapy. After 9 months, second-line therapy, including bevacizumab, was initiated. After another 7 months, echocardiography showed diffuse left ventricular dysfunction. Based on the histopathologic examination of the myocardium, the patient was diagnosed with ICI-related myocarditis. Initiation of prednisolone therapy improved cardiac function. This case of late-onset ICI-related myocarditis illustrates that endomyocardial biopsy can be useful in the differential diagnosis of cancer-related left ventricular dysfunction.

Il a été rapporté qu'une myocardite pouvait survenir peu après l'instauration d'un traitement par des inhibiteurs des points de contrôle immunitaire (ICI). Nous présentons le cas d'un homme de 78 ans atteint d'un cancer du poumon non à petites cellules. Le pembrolizumab a été administré comme traitement de première intention. Neuf mois plus tard, un traitement de deuxième intention par le bévacizumab a été instauré. Après sept autres mois, l'échocardiographie a montré une dysfonction ventriculaire gauche diffuse. À la suite des résultats de l'examen histopathologique du myocarde, une myocardite liée aux ICI a été diagnostiquée. L'instauration d'un traitement par la prednisolone a amélioré la fonction cardiaque du patient. Ce cas de myocardite tardive liée aux ICI montre l'utilité éventuelle de la biopsie de l'endomyocarde dans le diagnostic différentiel d'une dysfonction ventriculaire gauche liée au cancer.

Microthrombosis as a cause of fulminant myocarditis-like presentation with COVID-19 proven by endomyocardial biopsy.

Myocardial injury has been reported as a complication of COVID-19. Although several mechanisms have been proposed as its cause, they are mostly based on autopsy studies, We report a 49-year-old male with COVID-19-associated myocardial injury presented like fulminant myocarditis. We performed endomyocardial biopsy on day 2 and we confirmed the presence of microthrombosis histologically. He died on day 5 due to cardiogenic shock.

Crizotinib for ROS1-rearranged lung cancer and pulmonary tumor thrombotic microangiopathy under venoarterial extracorporeal membrane oxygenation.

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rapidly progressive subtype of pulmonary hypertension (PH) associated with impaired right ventricular adaptation and very poor prognosis in cancer, and its rapid progression makes antemortem diagnosis and treatment extremely difficult. We describe the case of a 35-year-old woman who developed severe PH with subsequent circulatory collapse. The patient was clinically diagnosed with PTTM induced by lung adenocarcinoma harboring the c-ros oncogene 1 (ROS1) rearrangement within 1-2 weeks, while hemodynamics were stabilized by rescue venoarterial extracorporeal membrane oxygenation support. Crizotinib, an oral tyrosine kinase inhibitor targeting anaplastic lymphoma kinase, MET, and ROS1 kinase domains dramatically resolved PH, resulting in more than 3 years of survival. Targeted gene-tailored therapy with mechanical support can improve survival in PTTM.