Dapagliflozin Alleviates Myocardial Inflammation by Regulating the Macrophage Polarization and Stat3-related Pathways in Coxsackie Virus B3-induced Acute Viral Myocarditis

Viral myocarditis (VMC), which is most prevalently caused by Coxsackievirus B3 (CVB3) infection, is a serious clinical condition characterized by cardiac inflammation. Dapagliflozin, a kind of sodium glucose co-transporters 2(SGLT-2) inhibitor, exhibited protective effects on plenty of inflammatory diseases, while its effect on viral myocarditis has not been studied. Recently we found the protective effect of dapagliflozin on VMC. After CVB3 infection, dapagliflozin were given orally to Balb/c male mice for 8 days and then the severity of myocarditis was assessed. Our results indicated that dapagliflozin significantly alleviated the severity of viral myocarditis, elevated the survival rate, and ameliorated cardiac function. Besides, dapagliflozin can decrease the level of proinflammatory cytokines included IL-1β, IL-6, TNF-α. Furthermore, dapagliflozin can inhibit macrophages differentiate to classically activated macrophages (M1) in cardiac tissue and activate the Stat3 signal pathway which is reported to promote polarization of the alternatively activated macrophage (M2). In conclusion, our study demonstrates that dapagliflozin alleviates myocardial inflammation by regulating the macrophage polarization and Stat3-related pathways in coxsackie virus B3-induced acute viral myocarditis.

Fulminant Myocarditis Following COVID-19 Vaccination: A Case Report

Background The BNT162b2 vaccine received emergency use authorization from the U.S. Food and Drug Administration for the prevention of severe COVID-19 infection. We report a case of biopsy and MRI-proven severe myocarditis that developed in a previously healthy individual within days of receiving the first dose of the BNT162b2 COVID-19 vaccine. Case Summary An 80-year-old female with no significant cardiac history presented with cardiogenic shock and biopsy-proven fulminant myocarditis within 12 days of receiving the BNT162b2 COVID-19 vaccine. She required temporary mechanical circulatory support, inotropic agents and high-dose steroids for stabilization and management. Ultimately her cardiac function recovered, and she was discharged in stable condition after 2 weeks of hospitalization. A repeat cardiac MRI 3 months after her initial presentation demonstrated stable biventricular function and continued improvement in myocardial inflammation. Discussion Fulminant myocarditis is a rare complication of vaccination. Clinicians should stay vigilant to recognize this rare, but potentially deadly complication. Due to the high morbidity and mortality associated with COVID-19 infection, the clinical benefits of the BNT162b2 vaccine greatly outweighs the risks of complications.

Dangshen Erling Decoction Ameliorates Myocardial Hypertrophy via Inhibiting Myocardial Inflammation

Myocardial hypertrophy plays an essential role in the structural remodeling of the heart and the progression to heart failure (HF). There is an urgent need to understand the mechanisms underlying cardiac hypertrophy and to develop treatments for early intervention. Dangshen Erling decoction (DSELD) is a clinically used formula in Chinese medicine for treating coronary heart disease in patients with HF. However, the mechanism by which DSELD produces its cardioprotective effects remains largely unknown. This study explored the effects of DSELD on myocardial hypotrophy both in vitro and in vivo. In vitro studies indicated that DSELD significantly (p < 0.05) reduced the cross-sectional area of the myocardium and reduced elevated lactate dehydrogenase (LDH), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 levels in the induced H9C2 cell model to study inflammation. In vivo experiments revealed that DSELD restores cardiac function and significantly reduces myocardial fibrosis in isoproterenol (ISO)-induced HF mouse model (p < 0.05). In addition, DSELD downregulated the expression of several inflammatory cytokines, such as granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte CSF (G-CSF), IL-1α, IL-1β, IL-3, IL-5, IL-7, IL-12, IL-13, and TNF-α in HF (p < 0.05). Further analysis of the cardiac tissue demonstrated that DSELD produces its anti-inflammatory effects via the Toll-like receptor (TLR)4 signaling pathway. The expression of TLR4 downstream proteins such as matrix metalloproteinase-9 (MMP9) and myeloid differentiation factor-88 (MyD88) was among the regulated targets. In conclusion, these observations suggest that DSELD exerts antihypertrophic effects by alleviating the inflammatory injury via the TLR4 signaling pathway in HF and thus holds promising therapeutic potentials.

Evaluation of [68Ga]Ga-NODAGA-RGD for PET Imaging of Rat Autoimmune Myocarditis

The 68Gallium-labeled 1,4,7-triazacyclononane-1-glutaric acid-4,7-diacetic acid conjugated radiolabelled arginine-glycine-aspartic acid peptide ([68Ga]Ga-NODAGA-RGD) is a positron emission tomography (PET) tracer binding to cell surface receptor αvβ3 integrin that is upregulated during angiogenesis and inflammation. We studied whether αvβ3 targeting PET imaging can detect myocardial inflammation in a rat model of autoimmune myocarditis. To induce myocarditis, rats (n = 8) were immunized with porcine cardiac myosin in complete Freund's adjuvant on days 0 and 7. Control rats (n = 8) received Freund's adjuvant alone. On day 21, in vivo PET/CT imaging with [68Ga]Ga-NODAGA-RGD followed by ex vivo autoradiography and immunohistochemistry were carried out. Inflammatory lesions were detected histologically in the myocardium of 7 out of 8 immunized rats. In vivo PET images showed higher [68Ga]Ga-NODAGA-RGD accumulation in the myocardium of rats with inflammation than the non-inflamed myocardium of control rats (SUVmean 0.4 ± 0.1 vs. 0.1 ± 0.02; P = 0.00006). Ex vivo autoradiography and histology confirmed that [68Ga]Ga-NODAGA-RGD uptake co-localized with inflammatory lesions containing αvβ3 integrin-positive capillary-like structures. A non-specific [68Ga]Ga-DOTA-(RGE)2 tracer showed 76% lower uptake than [68Ga]Ga-NODAGA-RGD in the inflamed myocardium. Our results indicate that αvβ3 integrin-targeting [68Ga]Ga-NODAGA-RGD is a potential PET tracer for the specific detection of active inflammatory lesions in autoimmune myocarditis.

118 Undefined left ventricular arrhythmogenic cardiomyopathy: the value of genotyping and histological characterization

Aims Etiology identification and risk stratification represent major issues for patients presenting with undefined left ventricular arrhythmogenic cardiomyopathy (ULVACM). To investigate the role of genotyping and histology for ULVACM classification, management, and risk assessment. Methods and results We retrospectively analysed a multicentre cohort of patients (screened n = 1037) with ULVACM defined by ventricular arrhythmia (VA) onset, nonischaemic late gadolinium enhancement (LGE) limited to the LV, and no manifest dilated cardiomyopathy (LVEF ≥ 40%). We selected patients undergoing both next generation sequencing (NGS) genotyping and endomyocardial biopsy (EMB) for etiology definition. When feasible, immunosuppressive therapy (IST) was used to target active myocardial inflammation (AMI). The study endpoint was a composite of cardiac death, heart transplantation and malignant VAs (VT, VF, appropriate ICD treatment). The study cohort is composed by 135 ULVACM patients (age 43 ± 14 years, 63% males, LVEF 55 ± 7%). NGS identified pathogenic or likely-pathogenic variants (PVs/LPVs) consistent with ACM in 21 cases (16%), whereas EMB showed AMI in 78 patients (58%), including 13/21 PVs/LPVs + (62%). IST was started in 41/78 AMI patients (53%), including 9/13 PVs/LPVs + (69%). Twenty patients (15%) met the study endpoint by 12 months, and 36 (27%) by the end of the study (60 ± 27 months). Beyond malignant VT onset, AMI was the only predictor of events by 12 months (HR: 5.0, 95% CI: 1.4–18.1, P = 0.007). No prognostic role was found for PVs/LPVs, except for the subgroup (n = 77) with nonsustained VT onset. Among AMI patients, those treated by IST had a significantly lower occurrence of events, both by 12-months (1/41 vs. 16/37, P < 0.001) and later (HR: 0.05, 95% CI: 0.01–0.21, P < 0.001). Results were independently confirmed in PVs/LPVs+ and PVs/LPVs- cases. Excluding the IST population, the association of multiple factors among VT onset, PVs/LPVs, and AMI, resulted in an improved discrimination of arrhythmic risk profiles. Conclusions Despite its limited diagnostic yield, the combined genetic and histological workup substantially contributed into ULVACM prognostic assessment. Furthermore, EMB identified suitable candidates for IST, who showed better outcomes irrespectively of their genotype.