Citations

Autoimmune diseases are a leading cause of disability worldwide. Most autoimmune diseases occur more often in women than men, with rheumatic autoimmune diseases being among those most highly expressed in women. Several key factors, identified mainly in animal models and cell culture experiments, are important in increasing autoimmune disease in females. These include sex hormones, immune genes including those found on the X chromosome, sex-specific epigenetic effects on genes by estrogen and the environment, and regulation of genes and messenger RNA by microRNAs found in extracellular vesicles. Evidence is also emerging that viruses as well as drugs or toxins that damage mitochondria may contribute to increased levels of autoantibodies against nuclear and mitochondrial antigens, which are common in many autoimmune diseases. The purpose of this Review is to summarize our current understanding of mechanisms that may determine sex differences in autoimmune disease.

Abstract Background Myocarditis is an inflammation of the heart muscle most often caused by an immune response to viral infections. Sex differences in the immune response during myocarditis have been well described but upstream mechanisms in the heart that might influence sex differences in disease are not completely understood. Methods Male and female BALB/c wild type mice received an intraperitoneal injection of heart-passaged coxsackievirus B3 (CVB3) or vehicle control. Bulk-tissue RNA-sequencing was conducted to better understand sex differences in CVB3 myocarditis. We performed enrichment analysis to understand sex differences in the transcriptional landscape of myocarditis and identify candidate transcription factors that might drive sex differences in myocarditis. Results The hearts of male and female mice with myocarditis were significantly enriched for pathways related to an innate and adaptive immune response compared to uninfected controls. When comparing females to males with myocarditis, males were enriched for inflammatory pathways and gene changes that suggested worse mitochondrial transcriptional support (e.g., mitochondrial electron transport genes). In contrast, females were enriched for pathways related to mitochondrial respiration and bioenergetics, which were confirmed by higher transcript levels of master regulators of mitochondrial function including peroxisome proliferator-activated receptor gamma coactivator 1 (PGC1α), nuclear respiratory factor 1 (NRF1) and estrogen-related receptor alpha (ERRα). TRANSFAC analysis identified ERRa as a transcription factor that may mediate sex differences in mitochondrial function during myocarditis. Conclusions Master regulators of mitochondrial function were elevated in females with myocarditis compared to males and may promote sex differences in mitochondrial respiratory transcript expression during viral myocarditis resulting in less severe myocarditis in females following viral infection.

Viral myocarditis is an inflammatory cardiomyopathy with no pharmacologic agent currently able to quell the immune mechanisms that damage the heart in their inflammatory crossfire to quell infections, without risk of immunocompromise. Sex differences are well known in inflammatory and/or infectious diseases. Females display more efficient, anti-inflammatory responses to external threats like viruses, while males launch a pro-inflammatory defensive response. Myocarditis is a classic case of an infectious, inflammatory disease being more frequent and more severe in men, while pre-menopausal women are most protected. Extracellular vesicles are biocompatible, highly abundant, stable messaging carriers with no transformative risk, and hold great promise as therapeutics due to their functional cargo. As EVs are soluble mediators of the conversations between cells, we seek to redirect protective anti-inflammatory messaging from pre-menopausal women to male mice, using a highly translational model of murine myocarditis. We derive EVs from omental fat, repurposing this source to derive a purified, therapeutic component. Our results show robust immune system control, with EV treatments effectively attenuating pro-inflammatory inflammasome and complement markers, while leaving regulatory components like M2b macrophages and complement component CR1 unchanged. Treated mice are healthier during acute disease and demonstrate better heart function than control mice, despite being a strain susceptible to myocarditis and subsequent dilated cardiomyopathy. Tests using EVs from similarly aged men do not demonstrate this anti-inflammatory capacity. Proteomic and RNA-sequencing content comparisons of these EVs from these two donor groups reveal important proteins and regulatory micro RNAs. Our data suggest that EVs from fat may be a novel anti-inflammatory treatment for viral myocarditis, however individual donors show varying therapeutic capacity, with EV content heavily influenced by sex and age. This study not only addresses a major therapeutic gap in the myocarditis field, but also provides functional and -omic based comparisons of EVs from donors differing only by sex, to test if female cardioprotection from myocarditis is transferrable.

AbstractPatients with viral myocarditis are at risk of sudden death and may progress to dilated cardiomyopathy (DCM). Currently, no disease‐specific therapies exist to treat viral myocarditis. Here it is examined whether reconstituted, lyophilized extracellular vesicles (EVs) from platelets from healthy men and women reduce acute or chronic myocarditis in male mice. Human‐platelet‐derived EVs (PEV) do not cause toxicity, damage, or inflammation in naïve mice. PEV administered during the innate immune response significantly reduces myocarditis with fewer epidermal growth factor (EGF)‐like module‐containing mucin‐like hormone receptor‐like 1 (F4/80) macrophages, T cells (cluster of differentiation molecules 4 and 8, CD4 and CD8), and mast cells, and improved cardiac function. Innate immune mediators known to increase myocarditis are decreased by innate PEV treatment including Toll‐like receptor (TLR)4 and complement. PEV also significantly reduces perivascular fibrosis and remodeling including interleukin 1 beta (IL‐1β), transforming growth factor‐beta 1, matrix metalloproteinase, collagen genes, and mast cell degranulation. PEV given at days 7–9 after infection reduces myocarditis and improves cardiac function. MicroRNA (miR) sequencing reveals that PEV contains miRs that decrease viral replication, TLR4 signaling, and T‐cell activation. These data show that EVs from the platelets of healthy individuals can significantly reduce myocarditis and improve cardiac function.

ObjectiveThe aim was to study laryngological complaints in patients with hypermobile Ehlers‐Danlos syndrome (hEDS) or hypermobility spectrum disorders (HSD).MethodsA total of 363 patients met inclusion for the study by completing questions related to voice, upper airway, and swallowing between July 7, 2020 and July 13, 2022. Demographic data, voice‐related questions, and hypermobility diagnosis were analyzed retrospectively. From those, 289 patients were diagnosed with hEDS or HSD with 74 that did not meet the diagnostic criteria for either diagnosis serving as controls.ResultsThere were no statistically significant differences between patients with hEDS and HSD regarding Voice Handicap Index (VHI‐10) scores, voice, upper airway, or swallow complaints. However, more hEDS/HSD patients answered positively to the laryngeal dysfunction question versus controls (p = 0.031). 22.5% of hEDS/HSD patients (n = 65) reported hoarseness, of which 52.3% reported hoarseness >2 days/month. 33.9% (n = 98) with hEDS/HSD reported symptoms of dysphagia, and 27.0% (n = 78) reported laryngeal dysfunction symptoms. Controls demonstrated 20.3% prevalence of hoarseness, of which 46.7% reported hoarseness >2 days/month. 24.3% of controls had dysphagia and 14.9% laryngeal dysfunction symptoms. Of the 363 patients, VHI‐10 scores >11 were more likely in patients reporting >2 days of hoarseness/month (p = 0.001) versus those with <2 days of hoarseness/month. There was an increased prevalence of voice, upper airway, and dysphagia symptoms in hEDS/HSD patients compared with previously reported prevalence data in the general population.ConclusionA significant proportion of patients diagnosed with hypermobility due to hEDS or HSD were found to have voice, upper airway, and dysphagia symptoms. These rates are higher than those previously reported in the general population.Level of Evidence3 Laryngoscope, 134:773–778, 2024

Viral infections are a leading cause of myocarditis and pericarditis worldwide, conditions that frequently coexist. Myocarditis and pericarditis were some of the early comorbidities associated with SARS-CoV-2 infection and COVID-19. Many epidemiologic studies have been conducted since that time concluding that SARS-CoV-2 increased the incidence of myocarditis/pericarditis at least 15× over pre-COVID levels although the condition remains rare. The incidence of myocarditis pre-COVID was reported at 1 to 10 cases/100 000 individuals and with COVID ranging from 150 to 4000 cases/100 000 individuals. Before COVID-19, some vaccines were reported to cause myocarditis and pericarditis in rare cases, but the use of novel mRNA platforms led to a higher number of reported cases than with previous platforms providing new insight into potential pathogenic mechanisms. The incidence of COVID-19 vaccine-associated myocarditis/pericarditis covers a large range depending on the vaccine platform, age, and sex examined. Importantly, the findings highlight that myocarditis occurs predominantly in male patients aged 12 to 40 years regardless of whether the cause was due to a virus-like SARS-CoV-2 or associated with a vaccine—a demographic that has been reported before COVID-19. This review discusses findings from COVID-19 and COVID-19 vaccine-associated myocarditis and pericarditis considering the known symptoms, diagnosis, management, treatment, and pathogenesis of disease that has been gleaned from clinical research and animal models. Sex differences in the immune response to COVID-19 are discussed, and theories for how mRNA vaccines could lead to myocarditis/pericarditis are proposed. Additionally, gaps in our understanding that need further research are raised.

Abstract The immunopathogenesis of autoimmune myocarditis and dilated cardiomyopathy (DCM) in humans is unpredictable and pathogenic mechanisms undefined. The aim was to investigate potential autoimmune mechanisms in human autoimmune myocarditis and heart failure. Our evidence for a Th17 immunophenotype in human myocarditis/DCM(n=40) included reduced CD4+CD25+FoxP3+ Tregulatory cells(0.0006), elevated Th17 cells(0.0008) and increased Th17-promoting cytokines(IL-6 and TGF-beta). Th1(IFNγ+) cells were not significantly elevated(p=0.7184). IL-6(&lt;0.0001), TGF-beta(0.0001), IL-23(0.0003), and GM-CSF+ T cells(0.0006) were significantly elevated. IL-17A+ cells were prevalent in biopsies from human myocarditis, non-recovery associated with persistence of IL-17A cytokines and heart failure associated with elevated Th17 cells in peripheral blood. To identify a potential mechanism to promote a Th17 pro-inflammatory pathogenesis in the heart, novel TLR ligands of human cardiac myosin (HCM) (peptides S2-16 and S2-28) promoted myocarditic PBMCs/CD14+ monocytes to produce Th17 cytokines(IL-23 p=0.0289; IL-6,TGF-beta p&lt;0.0001). TLR ligand stimulation of PBMCs/ monocytes was abrogated by antibodies blocking TLR2, IL-6, IL-17A/23, and GM-CSF. Our translational study suggested human myocarditis/DCM may be controlled by a Th17 phenotype including reduced Treg, elevated Th17 cells, and pro-inflammatory and pro-fibrotic Th17 cytokines triggered by cardiac myosin TLR ligands potentially released from heart.

Abstract An estimated 1 billion people worldwide have deficient or insufficient levels of vitamin D (VitD), while roughly 25% of individuals in the US are reported to have inadequate VitD levels. Considerable evidence indicates that VitD deficiency is associated with an increased risk of cardiovascular disease (CVD), yet it remains unclear whether low VitD is simply a biomarker of CVD or has a true pathologic role. The role of VitD deficiency in the pathogenesis of inflammatory myocarditis is unknown- a disease that is higher in men. We found that only 20% of myocarditis patients had low VitD levels. When we examined VitD receptor (VDR) deficient mice in a model of viral myocarditis, we found that VDR decreased myocarditis in females (p=0.007) but increased inflammation in males (p=0.006). Examination of cytokines in the heart found that VDR-/- male mice had significantly reduced IFN-γ and IL-1β and increased IL-17A, but no significant differences were found in females. Comparison of microarray data during myocarditis to published VitD response element genes revealed around 200 genes associated with proinflammatory (e.g. caspase-1) and profibrotic (e.g. TGF-β1, MMP) responses were increased in WT male mice, which was confirmed by qRT-PCR in VDR-/- mice. Our data confirms that VitD through the VDR promotes myocardial inflammation in males, providing a mechanism for how low VitD levels in men increase myocarditis. This work was funded by NIH R01 HL087033 and HL111938.