Single-cell RNA sequencing reveals the altered innate immunity in immune checkpoint inhibitor-related myocarditis.

Myocarditis has emerged as a rare but lethal immune checkpoint inhibitor (ICI)-associated toxicity. However, the exact mechanism and the specific therapeutic targets remain underexplored. In this study, we aim to characterise the transcriptomic profiles based on single-cell RNA sequencing from ICI-related myocarditis. Peripheral blood mononuclear cell (PBMC) samples were collected from four groups for single-cell RNA sequencing: (1) patients with newly diagnosed lung squamous cell carcinoma before treatment (Control Group); (2) patients with lung squamous cell carcinoma with PD-1 inhibitor therapy who did not develop myocarditis (PD-1 Group); (3) patients during fulminant ICI-related myocarditis onset (Myocarditis Group); and (4) Patients with fulminant ICI-related myocarditis during disease remission (Recovery Group). Subcluster determination, functional analysis, single-cell trajectory and cell-cell interaction analysis were performed after scRNA-seq. Bulk-RNA sequencing was performed for further validation. Our results revealed the diversity of cellular populations in ICI-related myocarditis, marked by their distinct transcriptional profiles and biological functions. Monocytes, NKs as well as B cells contribute to the regulation of innate immunity and inflammation in ICI-related myocarditis. With integrated analysis of scRNA-seq and bulk sequencing, we identified S100A protein family as a potential serum marker for ICI-related myocarditis. Our study has created a cell atlas of PBMC during ICI-related myocarditis, which would shed light on the pathophysiological mechanism and potential therapeutic targets of ICI-related myocarditis in continuous exploration.

Increased circulating uric acid aggravates heart failure via impaired fatty acid metabolism.

BACKGROUND: Increased circulating uric acid (UA) concentration may disrupt cardiac function in heart failure patients, but the specific mechanism remains unclear. Here, we postulate that hyperuremia induces sterol regulatory element binding protein 1 (SREBP1), which in turn activate hepatic fatty acid biosynthesis response, leading to cardiac dysfunction. METHODS AND RESULTS: Increased circulating uric acid was observed in heart failure patients and inversely correlated to cardiac function. Besides, uric acid correlated to circulating lipids profile based on metabolomics in heart failure patients. Using cultured human hepatoellular carcinomas (HepG2) and Tg(myl7:egfp) zebrafish, we demonstrated that UA regulated fatty acid synthase (FASN) via SREBP1 signaling pathway, leading to FFA accumulation and impaired energy metabolism, which could be rescued via SREBP1 knockdown. In ISO treated zebrafish, UA aggravated heart failure via increased cardiovascular cavity size, decreased heart beats, pericardial edema and long-stretched heart deformation. CONCLUSIONS: Our findings suggest that UA-SREBP1-FASN signaling exacerbates cardiac dysfunction during FFA accumulation. Identification of this mechanism may help in treatment and prevention of heart failure.

Case Report: Acute Myocarditis Due to PD-L1 Inhibitor Durvalumab Monotherapy in a Patient With Lung Squamous Cell Carcinoma.

Background: Durvalumab, as a PD-L1 inhibitor, is commonly used for the treatment of various cancers. Adverse events associated with the therapy include hepatitis, nephritis, dermatitis, and myocarditis. Especially, myocarditis as an adverse event after PD-L1 inhibitor therapy is characterized for its low incidence and high mortality. Case Summary: Here we present a rare case of a 67-year-old male with lung squamous cell carcinoma complicated with empyema who experienced myocarditis after only PD-L1 inhibitor durvalumab monotherapy. He presented with markedly decrease left ventricular ejection fraction, elevated Natriuretic peptide BNP, Troponin T, Troponin I, ESR, CRP and interleukin-6. The electrocardiogram showed sinus tachycardia, low voltage of limb leads, T wave inversion in anterior waves and V1-V3 QS type. Myocardial injury occurred in a short period and quickly returned to normal after glucocorticoids therapy. Conclusion: This case report is of clinical value for the treatment of PD-L1 related myocarditis.

Cardiotoxicity Related to Immune Checkpoint Inhibitors: A Real-World Retrospective Analysis.

Background: Cardiotoxicity related to immune checkpoint inhibitors (ICIs) is a rare but potentially lethal. In ICI-associated adverse events, evidence of cardiotoxicity and clinical predictive factors related to ICI is lacking. Here, we aim to assess the incidence and predictive factors of cardiotoxicity related to ICIs in real-world practice. Objective: We retrospectively analyzed consecutive patients who received PD-1 or PD-L1 at the First Affiliated Hospital of Xi'an Jiaotong University. Clinical characteristics and cardiac lesion markers were collected both at baseline and during longitudinal follow-up from the Biobank database. Follow-up CKMB and NT-proBNP levels and ratios were then evaluated. Results: A total of 2,304 patients with either PD-1 or PDL-1 utilization between August 2018 and April 2021 were collected. The average age was 59.44 ± 11.45 among PD-1 inhibitor utilizer and 58.97 ± 12.16 among PDL-1 inhibitor utilizer. The baseline creatine kinase isoenzyme MB (CKMB) levels were 17 ± 19 U/L in PD-1 inhibitor users and 17 ± 23 U/L in PDL-1 inhibitor users. Majority of patients were male, with advanced stage cancer, and received ICIs as second-line therapy. The longitudinal change of cardiac enzymes and NT-pro BNP were collected. Cardiac lesion as defined by three times increase of CKMB happens in only minority of patients receiving ICIs therapy. It is also identified that increased CKMB happened in PD-1 inhibitor groups, but not PDL-1 inhibitor groups. Conclusion: We evaluated the profile of cardiotoxicities caused by ICIs based on real-world experience. The cardiac lesion markers are generally unaltered, but it appears that the increased CKMB happened in PD-1 inhibitor groups, but not PDL-1 inhibitor groups.

Association between Cystatin C and Cardiac Function in Acute Myocardial Infarction Patients: A Real-World Analysis.

Background: Acute myocardial infarction (AMI), as well as its long-term and short-term complications, is known to present with high morbidity and mortality. Cardiac function deterioration and ventricular remodelling after AMI are known to be correlated to worse long-term outcomes. However, the underlying mechanism remains elusive and there is a shortage of serum prediction markers. This study investigates the relationship between in-hospital Cystatin C (CysC) and cardiac function and subsequent prognosis among AMI patients. Research Design and Methods. We measured admission CysC and cardiac function parameters, including ejection fraction (EF) and pro-BNP value in 5956 patients diagnosed with AMI. Simple and multiregression analyses were performed to investigate the correlation between CysC and cardiac function in AMI patients. Major adverse cardiovascular events (MACE), cardiovascular, and all-cause mortality were documented, and 351 participants with high cystatin (≥1.09 mg/L) and 714 low cystatin (<1.09 mg/L) were investigated for survival analysis during a 48-month follow-up. Results: 5956 patients with AMI were enrolled in the initial observational analysis, and 1065 patients of the whole cohort were included in the follow-up survival analysis. The admission CysC level was found to be significantly positively correlated to the pro-BNP level (R square = 0.2142, 95% CI 4758 to 5265, p < 0.0001) and negatively correlated to the EF value (R square = 0.0095, 95% CI -3.503 to -1.605, p < 0.0001). Kaplan-Meier survival analysis revealed significantly increased MACE incidence (HR = 2.293, 95% CI 1.400 to 3.755, p < 0.0001), cardiovascular mortality (HR = 3.016, 95% CI 1.694 to 5.371, p = 0.0002), and all-cause mortality (HR = 3.424, 95% CI 2.010 to 5.835, p < 0.0001) in high-admission CysC cohort with AMI at the end of 4-year follow-up. Conclusions: Admission CysC is negatively correlated with cardiac function in AMI patients and acts as a novel predictor for MACE incidence in the whole population. Further studies are needed to investigate the specific mechanism of CysC in the cardiac function deterioration among AMI patients.

Exosomal microRNA-16-5p from macrophage exacerbates atherosclerosis via modulating mothers against decapentaplegic homolog 7.

OBJECTIVE: Studies have probed the function of microRNA (miR)-16-5p in the progression of atherosclerosis (AS), while the regulatory function of exosomal miR-16-5p from macrophage on AS remains largely unknown. This study commits to exploring the efficiency of exosomal miR-16-5p from macrophage on AS via modulating mothers against decapentaplegic homolog 7 (SMAD7). METHODS: Macrophages were cultured and transfected with miR-16-5p antagomir, then, the exosomes from macrophages were extracted. The AS mouse model was established, and miR-16-5p or SMAD7 expression in AS mice was detected. Thereafter, the effects of macrophage-derived exosomes, miR-16-5p or SMAD7 on serum inflammatory response, oxidative stress response, pathological changes and apoptosis in AS mice were observed by immunohistochemical and biochemical analysis. Finally, the binding relation between miR-16-5p and SMAD7 was examined. RESULTS: MiR-16-5p was elevated while SMAD7 was depleted in AS mice. Macrophage-derived exosomes aggravated AS progression via facilitating inflammatory response and oxidative stress, exacerbating pathological changes and increasing cell apoptosis in AS mice; while downregulation of miR-16-5p reversed the exacerbation of AS progression by macrophage-derived exosomes in AS mice. MiR-16-5p targeted SMAD7, and the down-regulated SMAD7 reversed the impacts of depleted miR-16-5p on AS progression. CONCLUSION: Exosomal miR-16-5p from macrophages aggravates AS progression via downregulating SMAD7 expression. This study provides novel therapeutic targets for AS treatment from the animal level.

Dysregulated Arginine Metabolism in Young Patients with Chronic Persistent Asthma and in Human Bronchial Epithelial Cells.

BACKGROUND: Recent metabolomics studies have found circulatory metabolism alterations in patients with asthma, indicating that altered metabolites played a significant role in asthma. However, the regulatory mechanisms in asthma, especially in young chronic persistent asthma remain underexplored. METHODS: In this study, a prospective cohort of 162 patients diagnosed of asthma admitted to the First Affiliated Hospital of Xi'an Jiaotong University from January 2018 to December 2019 was used to perform a nested case-control study. Among them, we included 30 patients with chronic persistent asthma between 20 to 35 years old; 30 health control with evenly distributed age and sex were then recruited. Nontargeted metabolomics was applied to identify serum metabolic profiles and altered metabolic pathways. RESULTS: In vitro, human bronchial epithelial cells (HBECs) line BEAS-2B with the addition of L-citrulline and/or asymmetric dimethylarginine (ADMA) model was utilized and the concentrations of nitric oxide (NO) metabolites were tested to evaluate the therapeutic potential of L-citrulline. The young patients with chronic persistent asthma displayed dysregulated serum metabolic profiles, especially enriched in arginine metabolism. The ratio of L-citrulline to ornithine is associated with blood eosinophil count. In vitro, adding L-citrulline could reverse ADMA-mediated reduction of NOx at lower L-arginine concentration (25 µM), but was ineffective in the higher L-arginine concentration (100 µM) media. CONCLUSIONS: The arginine metabolism balance is of vital importance during the pathogenesis and progression of chronic asthma. L-citrulline could be a powerful approach to restore airway NO production, potentially exhibiting therapeutic benefits among young patients with chronic asthma.

Long-chain noncoding RNA-GAS5/hsa-miR-138-5p attenuates high glucose-induced cardiomyocyte damage by targeting CYP11B2.

OBJECTIVE: Diabetic cardiomyopathy (DCM) is one of the complications experienced by patients with diabetes. In recent years, long noncoding RNAs (lncRNAs) have been investigated because of their role in the progression of various diseases, including DCM. The purpose of the present study was to explore the role of lncRNA GAS5 in high glucose (HG)-induced cardiomyocyte injury and apoptosis. MATERIALS AND METHODS: We constructed HG-induced AC16 cardiomyocytes and a streptozotocin (STZ)-induced rat diabetes model. GAS5 was overexpressed and knocked out at the cellular level, and GAS5 was knocked down by lentiviruses at the animal level to observe its effect on myocardial injury. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of GAS5. Cell proliferation and apoptosis after GAS5 knockout were detected by CCK-8, TUNEL, and flow cytometry assays. ELISA was used to detect the changes in myocardial enzyme content in cells and animal myocardial tissues during the action of GAS5 on myocardial injury. RESULTS: GAS5 expression was up-regulated in HG-treated AC16 cardiomyocytes and the rat diabetic myocardial injury model. The down-regulation of GAS5 could inhibit HG-induced myocardial damage. This work proved that the down-regulation of GAS5 could reverse cardiomyocyte injury and apoptosis by targeting miR-138 to down-regulate CYP11B2. CONCLUSION: We confirmed for the first time that the down-regulation of GAS5 could reverse CYP11B2 via the miR-138 axis to reverse HG-induced cardiomyocyte injury. This research might provide a new direction for explaining the developmental mechanism of DCM and potential targets for the treatment of myocardial injury.

Pu-erh Tea Ameliorates Atherosclerosis Associated with Promoting Macrophage Apoptosis by Reducing NF-κB Activation in ApoE Knockout Mice.

We explored whether pu-erh tea consumption ameliorates atherosclerosis and the possible mechanism for its effects in apolipoprotein E-deficient (ApoE-/-) mice. Our data showed that pu-erh tea consumption markedly reduced early fatty streak formation and the advanced fibrofatty plaque sizes. Additionally, the mean proportion of inflammatory macrophages in the plaque decreased, and the number of apoptotic macrophages increased significantly. NF-κB activity in peritoneal macrophages decreased by 75.6% compared to the controls, similar with the levels of IL-6, IL-12, and TNF-α expression. The tea extract increased the apoptosis of RAW264.7 cells by decreasing NF-κB activation and reducing the inflammatory cytokine expression. In conclusion, pu-erh tea ameliorates atherosclerosis progress by alleviating the chronic inflammatory state by reducing NF-κB activation and promoting macrophage apoptosis in atherosclerotic plaques.

Chest Pain after Aortic Valve Replacement: Rupture of Right Sinus of Valsalva Presenting as Myocardial Infarction.

BACKGROUND: A 47-year-old male presented with retrosternal chest pain, which had started 4 days previously and had become excruciating for the past 6 h. He had undergone mechanical aortic valve replacement surgery 4 months previously. INVESTIGATION: Electrocardiography, echocardiography, computed tomography-angiography of the aorta. DIAGNOSIS: Rupture of the right sinus of Valsalva and right coronary artery dissection. MANAGEMENT: The defect in the right coronary sinus was closed, and the dissection at the root of the right coronary artery was resected and the right coronary artery bypassed to the root of the aorta.