Comparative safety profile of bivalent and original COVID-19 mRNA vaccines regarding myocarditis/pericarditis: A pharmacovigilance study.

OBJECTIVES: Bivalent COVID-19 mRNA vaccines, which contain two different components, were authorized to provide protection against both the original strain of SARS-CoV-2 and the Omicron variant as a measure to address the COVID-19 pandemic. Concerns regarding the risk of myocarditis/pericarditis associated with bivalent vaccination have been raised due to the observed superior neutralizing antibody responses. This study aimed to investigate the risk of myocarditis/pericarditis following bivalent COVID-19 mRNA vaccination compared to monovalent vaccination. METHODS: The CDC COVID Data Tracker and the Vaccines Adverse Event Reporting System (VAERS) were analyzed between December 13, 2020 to March 8, 2023. Reporting rates were determined by dividing the number of myocarditis/pericarditis cases by the total number of vaccine doses administered. Disproportionality patterns regarding myocarditis/pericarditis were evaluated for various COVID-19 mRNA vaccinations using reporting odds ratios (RORs). RESULTS: The reporting rate for myocarditis/pericarditis following original monovalent COVID-19 mRNA vaccination was 6.91 (95 % confidence interval [95 %CI] 6.71-7.12) per million doses, while the reporting rate for bivalent vaccination was significantly lower (1.24, 95%CI 0.96-1.58). Disproportionality analysis revealed a higher reporting of myocarditis/pericarditis following original vaccination with a ROR of 2.21 (95 %CI 2.00-2.43), while bivalent COVID-19 mRNA vaccination was associated with fewer reports of myocarditis/pericarditis (ROR 0.57, 95 %CI 0.45-0.72). Sub-analyses based on symptoms, sex, age and manufacturer further supported these findings. CONCLUSION: This population-based study provides evidence that bivalent COVID-19 mRNA vaccination is not associated with risk of myocarditis/pericarditis. These findings provide important insights into the safety profile of bivalent COVID-19 mRNA vaccines and support their continued use as updated boosters.

MG53 protects against Coxsackievirus B3-induced acute viral myocarditis in mice by inhibiting NLRP3 inflammasome-mediated pyroptosis via the NF-κB signaling pathway.

Pyroptosis, a novel programmed cell death mediated by NOD-like receptor protein 3 (NLRP3) inflammasome, is a critical pathogenic process in acute viral myocarditis (AVMC). Mitsugumin 53 (MG53) is predominantly expressed in myocardial tissues and has been reported to exert cardioprotective effects through multiple pathways. Herein, we aimed to investigate the biological function of MG53 in AVMC and its underlying regulatory mechanism in pyroptosis. BALB/c mice and HL-1 cells were infected with Coxsackievirus B3 (CVB3) to establish animal and cellular models of AVMC. As inflammation progressed in the myocardium, we found a progressive decrease in myocardial MG53 expression, accompanied by a significant enhancement of cardiomyocyte pyroptosis. MG53 overexpression significantly alleviated myocardial inflammation, apoptosis, fibrosis, and mitochondrial damage, thereby improving cardiac dysfunction in AVMC mice. Moreover, MG53 overexpression inhibited NLRP3 inflammasome-mediated pyroptosis, reduced pro-inflammatory cytokines (IL-1ß/18) release, and suppressed NF-κB signaling pathway activation both in vivo and in vitro. Conversely, MG53 knockdown reduced cell viability, facilitated cell pyroptosis, and increased pro-inflammatory cytokines release in CVB3-infected HL-1 cells by promoting NF-κB activation. These effects were partially reversed by applying the NF-κB inhibitor BAY 11-7082. In conclusion, our results suggest that MG53 acts as a negative regulator of NLRP3 inflammasome-mediated pyroptosis in CVB3-induced AVMC, partially by inhibiting the NF-κB signaling pathway. MG53 is a promising candidate for clinical applications in AVMC treatment.

Aerobic Exercise Attenuates Pressure Overload-Induced Myocardial Remodeling and Myocardial Inflammation via Upregulating miR-574-3p in Mice.

BACKGROUND: Exercise training can promote cardiac rehabilitation, thereby reducing cardiovascular disease mortality and hospitalization rates. MicroRNAs (miRs) are closely related to heart disease, among which miR-574-3p plays an important role in myocardial remodeling, but its role in exercise-mediated cardioprotection is still unclear. METHODS: A mouse myocardial hypertrophy model was established by transverse aortic coarctation, and a 4-week swimming exercise training was performed 1 week after the operation. After swimming training, echocardiography was used to evaluate cardiac function in mice, and histopathologic staining was used to detect cardiac hypertrophy, myocardial fibrosis, and cardiac inflammation. Quantitative real-time polymerase chain reaction was used to detect the expression levels of miR-574-3p and cardiac hypertrophy markers. Western blotting detected the IL-6 (interleukin-6)/JAK/STAT inflammatory signaling pathway. RESULTS: Echocardiography and histochemical staining found that aerobic exercise significantly improved pressure overload-induced myocardial hypertrophy (n=6), myocardial interstitial fibrosis (n=6), and cardiac inflammation (n=6). Quantitative real-time polymerase chain reaction detection showed that aerobic exercise upregulated the expression level of miR-574-3p (n=6). After specific knockdown of miR-574-3p in mouse hearts with adeno-associated virus 9 using cardiac troponin T promoter, we found that the protective effect of exercise training on the heart was significantly reversed. Echocardiography and histopathologic staining showed that inhibiting the expression of miR-574-3p could partially block the effects of aerobic exercise on cardiac function (n=6), cardiomyocyte cross-sectional area (n=6), and myocardial fibrosis (n=6). Western blotting and immunohistochemical staining showed that the inhibitory effects of aerobic exercise on the IL-6/JAK/STAT pathway and cardiac inflammation were partially abolished after miR-574-3p knockdown. Furthermore, we also found that miR-574-3p exerts cardioprotective effects in cardiomyocytes by targeting IL-6 (n=3). CONCLUSIONS: Aerobic exercise protects cardiac hypertrophy and inflammation induced by pressure overload by upregulating miR-574-3p and inhibiting the IL-6/JAK/STAT pathway.

Pre-treatment with galectin-1 attenuates lipopolysaccharide-induced myocarditis by regulating the Nrf2 pathway.

Galectin-1 (Gal-1), a member of a highly conserved family of animal lectins, plays a crucial role in controlling inflammation and neovascularization. However, the potential role of Gal-1 in preventing myocarditis remains uncertain. We aimed to explore the functions and mechanisms of Gal-1 in preventing myocarditis. In vivo, C57/BL6 mice were pre-treated with or without Gal-1 and then exposed to lipopolysaccharide (LPS) to induce myocarditis. Subsequently, cardiac function, histopathology, inflammation, oxidative stress, and apoptosis of myocardial tissues were detected. Following this, qRT-PCR and Western blotting were applied to measure iNOS, COX2, TXNIP, NLRP3 and Caspase-1 p10 expressions. In vitro, H9c2 cells pre-treated with different doses of Gal-1 were stimulated by LPS to induce myocarditis models. CCK8, flow cytometry and reactive oxygen species (ROS) assay were then employed to estimate cell viability, apoptosis and oxidative stress. Furthermore, Nrf2 and HO-1 protein expressions were evaluated by Western blotting in vivo and in vitro. The results showed that in vivo, Gal-1 pre-treatment not only moderately improved cardiac function and cardiomyocyte apoptosis, but also ameliorated myocardial inflammation and oxidative damage in mice with myocarditis. Furthermore, Gal-1 inhibited TXNIP-NLRP3 inflammasome activation. In vitro, Gal-1 pre-treatment prevented LPS-induced apoptosis, cell viability decrease and ROS generation. Notably, Gal-1 elevated HO-1, total Nrf2 and nuclear Nrf2 protein expressions both in vivo and in vitro. In conclusion, pre-treatment with Gal-1 exhibited cardioprotective effects in myocarditis via anti-inflammatory and antioxidant functions, and the mechanism may relate to the Nrf2 pathway, which offered new solid evidence for the use of Gal-1 in preventing myocarditis.

CCL17 Protects Against Viral Myocarditis by Suppressing the Recruitment of Regulatory T Cells.

Background Viral myocarditis is characterized by leukocyte infiltration of the heart and cardiomyocyte death. We recently identified C-C chemokine ligand (CCL) 17 as a proinflammatory effector of C-C chemokine receptor 2-positive macrophages and dendritic cells that are recruited to the heart and contribute to adverse left ventricular remodeling following myocardial infarction and pressure overload. Methods and Results Mouse encephalomyocarditis virus was used to investigate the function of CCL17 in a viral myocarditis model. Ccl17Gfp reporter and knockout mice were used to identify the cell types that express CCL17 and delineate the functional importance of CCL17 in encephalomyocarditis virus clearance and myocardial inflammation. Cardiac CCL17 was expressed in C-C chemokine receptor 2-positive macrophages and dendritic cells following encephalomyocarditis virus infection. Colony-stimulating factor 2 (granulocyte-macrophage colony-stimulating factor) signaling was identified as a key regulator of CCL17 expression. Ccl17 deletion resulted in impaired encephalomyocarditis virus clearance, increased cardiomyocyte death, and higher mortality during infection early stage, and aggravated hypertrophy and fibrotic responses in infection long-term stage. An increased abundance of regulatory T cells was detected in the myocardium of injured Ccl17-deficient mice. Depletion of regulatory T cells in Ccl17-deficient mice abrogated the detrimental role of CCL17 deletion by restoring interferon signaling. Conclusions Collectively, these findings identify CCL17 as an important mediator of the host immune response during cardiac viral infection early stage and suggest that CCL17 targeted therapies should be avoided in acute viral myocarditis.

Exosome-based delivery of VP1 protein conferred enhanced resistance of mice to CVB3-induced viral myocarditis.

Coxsackievirus B3 (CVB3) is an important cause of viral myocarditis with no vaccine available in clinic. Herein we constructed an exosome-based anti-CVB3 vaccine (Exo-VP1), and compared its immunogenicity and immunoprotection with our previously reported recombinant VP1 protein (rVP1) vaccine. We found that compared with the 25 µg rVP1 vaccine, Exo-VP1 vaccine containing only 2 µg VP1 protein induced much stronger CVB3-specific T cell proliferation and CTL responses (with an increase of more than 70% and 40% respectively), and elicited greater splenic Th1/CTL associated cytokines (IFN-γ, TNF-α and IL-12). Furthermore, higher IgG levels with increased neutralizing titers and avidity were also evidenced in Exo-VP1 group. Consistently, Exo-VP1 group exhibited enhanced resistance to viral myocarditis than rVP1 vaccine, reflected by reduced cardiac viral loads, improved myocardial inflammation and an increased survival rate. Collectively, we reported that Exo-VP1 might present a more potent CVB3 vaccine candidate than rVP1 vaccine.

Neutrophil inhibition improves acute inflammation in a murine model of viral myocarditis.

AIMS: Viral myocarditis (VM) is an inflammatory pathology of the myocardium triggered by a viral infection that may cause sudden death or heart failure (HF), especially in the younger population. Current treatments only stabilize and improve cardiac function without resolving the underlying inflammatory cause. The factors that induce VM to progress to HF are still uncertain, but neutrophils have been increasingly associated with the negative evolution of cardiac pathologies. The present study investigates the contribution of neutrophils to VM disease progression in different ways. METHODS AND RESULTS: In a coxsackievirus B3- (CVB3) induced mouse model of VM, neutrophils and neutrophil extracellular traps (NETs) were prominent in the acute phase of VM as revealed by enzyme-linked immunosorbent assay analysis and immunostaining. Anti-Ly6G-mediated neutrophil blockade starting at model induction decreased cardiac necrosis and leucocyte infiltration, preventing monocyte and Ly6CHigh pro-inflammatory macrophage recruitment. Furthermore, genetic peptidylarginine deiminase 4-dependent NET blockade reduced cardiac damage and leucocyte recruitment, significantly decreasing cardiac monocyte and macrophage presence. Depleting neutrophils with anti-Ly6G antibodies at 7 days post-infection, after the acute phase, did not decrease cardiac inflammation. CONCLUSION: Collectively, these results indicate that the repression of neutrophils and the related NET response in the acute phase of VM improves the pathological phenotype by reducing cardiac inflammation.

Risk of adverse events after covid-19 in Danish children and adolescents and effectiveness of BNT162b2 in adolescents: cohort study.

OBJECTIVES: To assess the risk of acute and post-acute adverse events after SARS-CoV-2 infection in children and adolescents in Denmark and to evaluate the real world effectiveness of the BNT162b2 mRNA vaccine (Pfizer-BioNTech) among adolescents. DESIGN: Cohort study. SETTING: Nationwide Danish healthcare registers. PARTICIPANTS: All Danish people younger than 18 years who were either tested for SARS-CoV-2 using reverse transcriptase polymerase chain reaction (RT-PCR) or vaccinated with BNT162b2 to 1 October 2021. MAIN OUTCOME MEASURES: Risk of hospital admissions (any hospital contact of ≥12 hours); intensive care unit (ICU) admissions; serious complications, including multisystem inflammatory syndrome in children (MIS-C), myocarditis, and neuroimmune disorders; and initiating drug treatment and health service use up to six months after being tested. Vaccine effectiveness in vaccine recipients compared with unvaccinated peers was evaluated as one minus the risk ratio at 20 days after the first dose and 60 days after the second dose. RESULTS: Of 991 682 children and adolescents tested for SARS-CoV-2 using RT-PCR in Denmark, 74 611 (7.5%) were positive. The risk of hospital admission with any variant for ≥12 hours was 0.49% (95% confidence interval 0.44% to 0.54%; 361/74 350), and 0.01% (0.01% to 0.03%; 10/73 187) of participants were admitted to an ICU within 30 days of testing positive. The risk of MIS-C within two months of SARS-CoV-2 infection was 0.05% (0.03% to 0.06%; 32/70 666), whereas no participants had myocarditis outside of MIS-C or encephalitis and fewer than five had Guillain-Barré syndrome. In the post-acute phase (1-6 months after infection), participants who tested positive for SARS-CoV-2 showed a 1.08-fold (95% confidence interval 1.06-fold to 1.10-fold) increase in rate of contacts with general practitioners compared with a reference cohort sampled among all children tested for SARS-CoV-2 during the study period. Overall, 278 649 adolescents received BNT162b2. Compared with unvaccinated adolescents, the estimated vaccine effectiveness among 229 799 adolescents vaccinated with one dose was 62% (95% confidence interval 59% to 65%) after 20 days, and among 175 176 vaccinated with two doses was 93% (92% to 94%) after 60 days during a period when delta was the dominant variant. CONCLUSIONS: The absolute risks of adverse events after SARS-CoV-2 infection were generally low in Danish children and adolescents, although MIS-C occurred in 0.05% (32/70 666) of participants with RT-PCR confirmed SARS-CoV-2 infection. In adjusted analyses, rates of general practitioner visits were slightly increased in SARS-CoV-2 positive children and adolescents, which could indicate persisting symptoms. BNT162b2 appeared to be effective in reducing the risk of SARS-CoV-2 infection with the delta variant in adolescents.

2-undecanone protects against fine particles-induced heart inflammation via modulating Nrf2/HO-1 and NF-κB pathways.

Exposure to air pollution has been closely associated with some cardiovascular disease. One of the mechanisms of PM2.5 -mediated heart injury may be to promote inflammation. We aim to investigate whether the main extract of Houttuynia cordata, 2-undecanone, can prevent the inflammation caused by PM2.5 , and to reveal the underlying mechanisms. The results showed that PM2.5 increased the expression of certain inflammatory cytokines, and caused oxidative damage in BALB/c mice and H9C2 cells. Supplementation with 2-undecanone attenuated this PM2.5 -induced inflammatory injury and oxidative damage. Further, we elucidated that the protective effect of 2-undecanone may be associated with NF-κB and Nrf2/HO-1 pathways. The NF-κB pathway was distinctly activated after treated by PM2.5 , which can be blocked by 2-undecanone, accompanied by increasing Nrf2 and HO-1 levels. To figure out the relationship between NF-κB and Nrf2/HO-1 pathways, we knocked down Nrf2 gene. NF-κB pathway proteins and downstream inflammatory cytokines were significantly increased after treatment with PM2.5 , while 2-undecanone could decrease expression of these proteins. In conclusion, it is possible that 2-undecanone can induce the expression of the antioxidant enzyme HO-1 by activating Nrf2, thereby reducing NF-κB pathway and inflammatory damage of mouse myocardium caused by PM2.5 exposure.

Sports, Myocarditis and COVID-19: Diagnostics, Prevention and Return-to-play Strategies.

Myocarditis is an umbrella term for non-ischemic myocardial inflammation and remains a leading cause of sudden cardiac death in active individuals and athletes. Accurate diagnosing is challenging and diseases could often remain undetected. In the majority of cases, acute myocarditis resolves favourably. However, a relevant proportion of patients may have an increased risk of prognostically relevant cardiac arrhythmias and/or the development and progression of maladaptive myocardial remodelling (dilated cardiomyopathy). This review provides current knowledge on myocarditis and sports with special regard to the COVID-19 pandemic. Possible causes, common symptoms and proposed diagnostics are summarized. The relevance of temporary avoidance of intensive sports activities for both the prevention and therapy of acute myocarditis is discussed. Risk stratification, specific return-to-play recommendations and proposed follow-up diagnostics (also after COVID-19 infection) are presented.

Rosuvastatin exerts cardioprotective effect in lipopolysaccharide-mediated injury of cardiomyocytes in an MG53-dependent manner.

BACKGROUND: Myocarditis is a cardiomyopathy associated with the inflammatory response. Rosuvastatin (RS) demonstrates cardioprotective effect in the clinical setting, although its cellular and molecular mechanisms in ameliorating myocarditis are largely unknown. MG53 (muscle-specific E3 ligase Mitsugumin 53), a newly identified striated muscle-specific protein, is involved in skeletal muscle membrane repair. We aimed to explore whether RS mediated the repair of cardiomyocytes in an MG53-dependent manner. METHODS: The RS-induced upregulation of MG53 was determined using RT-qPCR and western blotting. A lipopolysaccharide (LPS)-induced cell inflammatory model was constructed using rat cardiac muscle cell H9C2. Inflammatory injury was evaluated according to the alterations of cell viability, mitochondrial membrane potential, cell apoptosis, and expression of pro-inflammatory cytokines (interleukin-1ß, interleukin-6, tumor necrosis factor-α, and monocyte chemoattractant protein-1). Small interfering RNAs (siRNAs) were used to silence MG53. The cardioprotective effect of RS and the inhibition of this protection by MG53 silence were evaluated in the forementioned in vitro model. The underlying mechanism was finally investigated using western blotting to detected the expressions of apoptotic markers (Bcl-2, Bax, Cleaved caspase-9, Cleaved caspase-3), cell cycle regulatory factors (Cyclin A, Cyclin E1, Cyclin D1, CDK2), and components involved in NF-κB signaling pathway (p-IκBa, Iκba, p-p65, p65). RESULTS: RS ameliorated LPS-induced inflammatory injury. RS upregulated the expression of MG53. MG53 was crucial for the RS-mediated repair response in vitro. Ablation of MG53 inhibited the RS-mediated protective effect. Furthermore, RS and MG53 interact in multiple signaling pathways to modulate recovery. CONCLUSION: RS exerts cardioprotective effect in an MG53-dependent manner. MG53 may serve as a novel drug target for myocarditis treatment.

Colchicine prevents disease progression in viral myocarditis via modulating the NLRP3 inflammasome in the cardiosplenic axis.

AIM: The acute phase of a coxsackievirus 3 (CVB3)-induced myocarditis involves direct toxic cardiac effects and the systemic activation of the immune system, including the cardiosplenic axis. Consequently, the nucleotide-binding oligomerization domain-like receptor pyrin domain-containing-3 (NLRP3) inflammasome pathway is activated, which plays a role in disease pathogenesis and progression. The anti-inflammatory drug colchicine exerts its effects, in part, via reducing NLRP3 activity, and has been shown to improve several cardiac diseases, including acute coronary syndrome and pericarditis. The aim of the present study was to evaluate the potential of colchicine to improve experimental CVB3-induced myocarditis. METHODS AND RESULTS: C57BL6/j mice were intraperitoneally injected with 1 × 105 plaque forming units of CVB3. After 24 h, mice were treated with colchicine (5 µmol/kg body weight) or phosphate-buffered saline (PBS) via oral gavage (p.o.). Seven days post infection, cardiac function was haemodynamically characterized via conductance catheter measurements. Blood, the left ventricle (LV) and spleen were harvested for subsequent analyses. In vitro experiments on LV-derived fibroblasts (FB) and HL-1 cells were performed to further evaluate the anti-(fibro)inflammatory and anti-apoptotic effects of colchicine via gene expression analysis, Sirius Red assay, and flow cytometry. CVB3 + colchicine mice displayed improved LV function compared with CVB3 + PBS mice, paralleled by a 4.7-fold (P < 0.01) and 1.7-fold (P < 0.001) reduction in LV CVB3 gene expression and cardiac troponin-I levels in the serum, respectively. Evaluation of components of the NLRP3 inflammasome revealed an increased percentage of apoptosis-associated speck-like protein containing a CARD domain (ASC)-expressing, caspase-1-expressing, and interleukin-1ß-expressing cells in the myocardium and in the spleen of CVB3 + PBS vs. control mice, which was reduced in CVB3 + colchicine compared with CVB3 + PBS mice. This was accompanied by 1.4-fold (P < 0.0001), 1.7-fold (P < 0.0001), and 1.7-fold (P < 0.0001) lower numbers of cardiac dendritic cells, natural killer cells, and macrophages, respectively, in CVB3 + colchicine compared with CVB3 + PBS mice. A 1.9-fold (P < 0.05) and 4.6-fold (P < 0.001) reduced cardiac gene expression of the fibrotic markers, Col1a1 and lysyl oxidase, respectively, was detected in CVB3 + colchicine mice compared with CVB3 + PBS animals, and reflected by a 2.2-fold (P < 0.05) decreased Collagen I/III protein ratio. Colchicine further reduced Col3a1 mRNA and collagen protein expression in CVB3-infected FB and lowered apoptosis and viral progeny release in CVB3-infected HL-1 cells. In both CVB3 FB and HL-1 cells, colchicine down-regulated the NLRP3 inflammasome-related components ASC, caspase-1, and IL-1ß. CONCLUSIONS: Colchicine improves LV function in CVB3-induced myocarditis, involving a decrease in cardiac and splenic NLRP3 inflammasome activity, without exacerbation of CVB3 load.

Protective role of nutraceuticals against myocarditis.

Myocarditis is an inflammatory disease of the myocardium that mostly affects young adults. The disease is commonly caused by viral infection, medications, autoimmune disorders, and inflammatory conditions. Nearly 50% of the cases of myocarditis are due to post-viral immune response in a setting of an identifiable or non-identifiable infection. The clinical manifestation is nonspecific ranging from asymptomatic courses to sudden death in infants and young patients. This review describes the properties of phytochemicals as plant-derived active ingredients which can be used in the prevention and treatment of myocarditis and its associated risk factors. Meanwhile, it has illustrated epidemiological analyses, mechanism of action, and the metabolism of phytochemicals in animal and human clinical trials. We also mentioned the precise mechanism of action by which phytochemicals elicit their anti-viral, anti-inflammatory, antioxidant, and immunomodulatory effects and how they regulate signal transduction pathways. Nevertheless, comprehensive clinical trials are required to study the properties of phytochemicals in vivo, in vitro, and in silico for a proper management of myocarditis. Our findings indicate that phytochemicals function as potent adjunctive therapeutic drugs in myocarditis and its related complications.

An Albumin-Binding Domain Peptide Confers Enhanced Immunoprotection Against Viral Myocarditis by CVB3 VP1 Vaccine.

Coxsackievirus B3 (CVB3)-induced viral myocarditis is a common clinical cardiovascular disease without effective available vaccine. In this study, we tried to potentiate the immunoprotection efficacy of our previous CVB3-specific VP1 protein vaccine by introducing a streptococcal protein G-derived, draining lymph nodes (dLNs)-targeting albumin-binding domain (ABD) peptide. We found that compared with the original VP1 vaccine, ABD-fused VP1 (ABD-VP1) vaccine gained the new ability to efficiently bind murine albumin both in vitro and in vivo, possessed a much longer serum half-life in serum and exhibited more abundance in the dLNs after immunization. Accordingly, ABD-VP1 immunization not only significantly facilitated the enrichment and maturation of dendritic cells (DCs), induced higher percentages of IFN-γ+ CD8 + cells in the dLNs, but also robustly promoted VP1-induced T cell proliferation and cytotoxic T lymphocyte (CTL) responses in the spleens. More importantly, ABD-VP1 also elicited higher percentages of protective CD44hi CD62Lhi memory T cells in dLNs and spleens. Consequently, obvious protective effect against viral myocarditis was conferred by ABD-VP1 vaccine compared to the VP1 vaccine, reflected by the less body weight loss, improved cardiac function, alleviated cardiac histomorphological changes and an increased 28-day survival rate. Our results indicated that the ABD might be a promising immune-enhancing regime for vaccine design and development.

Curcumin analogue C66 attenuates obesity-induced myocardial injury by inhibiting JNK-mediated inflammation.

Obesity has been recognized as a major risk factor for the development of chronic cardiomyopathy, which is associated with increased cardiac inflammation, fibrosis, and apoptosis. We previously developed an anti-inflammatory compound C66, which prevented inflammatory diabetic complications via targeting JNK. In the present study, we have tested the hypothesis that C66 could prevent obesity-induced cardiomyopathy by suppressing JNK-mediated inflammation. High-fat diet (HFD)-induced obesity mouse model and palmitic acid (PA)-challenged H9c2 cells were used to develop inflammatory cardiomyopathy and evaluate the protective effects of C66. Our data demonstrate a protective effect of C66 against obesity-induced cardiac inflammation, cardiac hypertrophy, fibrosis, and dysfunction, overall providing cardio-protection. C66 administration attenuates HFD-induced myocardial inflammation by inhibiting NF-κB and JNK activation in mouse hearts. In vitro, C66 prevents PA-induced myocardial injury and apoptosis in H9c2 cells, accompanied with inhibition against PA-induced JNK/NF-κB activation and inflammation. The protective effect of C66 is attributed to its potential to inhibit JNK activation, which led to reduced pro-inflammatory cytokine production and reduced apoptosis in cardiomyocytes both in vitro and in vivo. In summary, C66 provides significant protection against obesity-induced cardiac dysfunction, mainly by inhibiting JNK activation and JNK-mediated inflammation. Our data indicate that inhibition of JNK is able to provide significant protection against obesity-induced cardiac dysfunction.

[Cardiotoxicity of Anti-PD-L1 Antibody and the Effect of Levothyroxine 
in Attenuating the Related Mortality in Mice].

BACKGROUND: Immune checkpoint inhibitors (ICIs) such as antibodies against programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1), have shown remarkable efficacies in many subtypes of cancers. However, ICIs may also cause severe immune-related adverse events in the recipient patients. Recently, ICI-associated myocarditis have been reported in hundreds of patients worldwide, with a mortality rate of approximately 50% in these cases. This study aims to recapitulate the cardiotoxicity and explore the detoxicifying approaches to attenuate mortality caused by PD-1/PD-L1 inhibitors in healthy mice. METHODS: Six to eight-week-old C57BL/6 mice were inoculated with anti-PD-1 antibody (12.5 µg/g every 5 days for 6 injections), anti-PD-L1 antibody (10 µg/g once a week for 6 weeks), anti-PD-L1 antibody (with the same dosage described above) in combination with levothyroxine (0.25 µg/g, intraperitoneally injected half an hour before anti-PD-L1 antibody injection), or isotype control immunoglobulin IgG (10 µg/g once a week for 6 weeks). The ejection function of the hearts was detected by echocardiography, body temperature and blood pressure were detected by Mouse MonitorTM and non-invassive blood pressure minotor, and serum free thyroxine concentration was detected by The enzyme linked immunosorbent assay (ELISA). RESULTS: PD-L1 was expressed at different levels by the cardiomyocytes of the mice. The isotype control immunoglobulin and anti-PD-1 antibody did not cause death of the mice. The 12 mice receiving 3-6 injections of anti-PD-L1 antibody showed a significant increase in the heart-to-tibial ratio and cardiomyoctye degeneration, hyalinization and extravascular inflammatory cell infiltration. In addition, the serum thyroxine was mardedly decreased to 1/3 of that in the control group mice, and the blood pressure and body temperature were abnormally decreased in mice upon treatment with PD-L1 blockade. Eight of the 12 (66.7%) mice died from multiple intravenous injection of anti-PD-L1 antibody.Intraperitoneal injection of levothyroxine 30 min before the injection of anti-PD-L1 antibody significantly attenuated the mortality rate of the anti-PD-L1 antibody-treated mice. CONCLUSIONS: The anti-PD-L1 antibody is cardiotoxic and lethal, and levothyroxine is able to rescue the mice from this immune checkpoint inhibitor-caused mortality.