Citations

Background: Viral myocarditis presents a significant burden of disease, particularly among children and young adults. However, clinical guidelines and treatment strategies for pediatric patients are derived from those for adult patients due to a lack of pediatric data. Current animal models of viral myocarditis use adult mice, so conclusions from these models cannot necessarily be extrapolated to the pediatric population. We sought to develop a juvenile mouse model of myocarditis to examine differences between these two distinct clinical populations. Methods: Male and female BALB/c 3-4-week-old 'juvenile' and 8-week-old 'adult' mice were infected intraperitoneally with 103 PFU of heart-passaged coxsackievirus B3. Sera was used to evaluate testosterone and estradiol levels. Cardiac histological evaluations included overall inflammation, fibrosis, and specific cell-type infiltration. RNA was extracted from cardiac tissue and evaluated for changes in gene expression of cell-type markers, complement components, and NLRP3 inflammasome components. Results: Juvenile mice exhibited more severe inflammation than adult mice but no sex differences in overall inflammation. Juvenile mice demonstrated increased infiltration of CD11b+ cells, F4/80+ cells, and CD3+ T-cells vs. adults. Inflammasome genes NLRP3 and caspase-1 were significantly increased in juvenile compared with adult myocarditis. Conclusions: This paper is the first to describe a juvenile mouse model of coxsackievirus B3 myocarditis and provides a direct comparison to a translational adult mouse model. Juvenile mice had greater cardiac inflammation than adults. This model replicates clinical populations and provides a valuable tool to study age as a factor in the pathogenesis of myocarditis.

Stem cell-derived β (SC-β) cells are a promising therapy for type 1 diabetes (T1D), but their long-term efficacy is limited by immune-mediated graft rejection. Platelet-derived exosome product (PEP) has emerged as a novel immunomodulatory agent, although its effect on SC-β cell xenograft rejection remains unclear. Here, we evaluated PEP in stimulated human peripheral blood mononuclear cells (PBMCs) and in an immunocompetent mouse model of SC-β cell transplantation under the kidney capsule. Immune-related gene expression was assessed by quantitative PCR, immune cell infiltration by immunofluorescence, and graft function by circulating human insulin. In vitro, PEP reduced NK-cell-associated gene expression, including NK1.1, EOMES, and KLRK1, and increased IL-10 expression. In vivo, untreated SC-β cell xenografts showed progressive immune infiltration and loss of detectable human insulin by day 14, whereas PEP-treated grafts retained detectable insulin through day 14 across co-transplantation, pretreatment, and systemic administration strategies. PEP co-transplantation delayed, but did not prevent, xenograft rejection, with graft loss observed by day 21. This delay was associated with reduced NK1.1+ cell infiltration and lower expression of selected inflammatory and rejection-associated markers, including NK1.1, Nos2, and Nlrp3. These findings suggest that PEP modulates graft-associated immune responses and may serve as an adjunct immunomodulatory strategy for stem cell-based therapies for type 1 diabetes. Further studies are needed to evaluate sustained graft durability, safety, and translational efficacy.

Abstract Background Radiation-induced heart disease (RIHD) may develop months to years following radiation therapy for cancers near the heart such as lung or breast cancer. Several mouse models of RIHD exist to study the pathogenesis of disease, but to our knowledge no studies have examined whether sex differences exist in RIHD in mice. Methods Female and male BALB/cJ mice received one whole heart dose of 22 Gray (Gy) radiation via a C5 collimator vs. sham controls that received 0 Gy, anesthesia and were placed in the X-ray machine for the same length of time. Mechanisms of cardiotoxicity were examined at 24 h (innate cardiotoxicity), day 10 (acute cardiotoxicity) and day 35 (chronic cardiotoxicity) post irradiation. Results Females and males developed dsDNA breaks from radiation at day 10 but females had more damage than males ( p < 0.001). Vessel area and cardiac hypertrophy were increased by radiation at day 10 and 35 but were higher in males than females at day 35 ( p < 0.001, p = 0.001, respectively). Bulk RNA sequencing of the heart at day 10 revealed that females and males developed similar gene pathway responses to radiation by upregulating cellular repair pathways and downregulated mitochondrial function. However, females upregulated the master regulator of mitochondrial function, Pgc1α ( p = 0.0001), suggesting improved mitochondrial repair in females. By day 35, males developed heart failure with reduced ejection fraction (HFrEF), inflammatory dilated cardiomyopathy (iDCM) and fibrosis while females developed heart failure with preserved ejection fraction (HFpEF) without inflammation or fibrosis. Conclusions We observed sex differences in nearly every cardiac parameter that we examined following radiation exposure. BALB/c males exposed to 22 Gy radiation developed HFrEF and iDCM by day 35 while females developed HFpEF. Further research is needed to better understand mechanisms driving sex differences in RIHD using translational animal models.

Abstract Myocarditis and valvulitis are inflammatory diseases affecting myocardium and heart valves. Myocarditis, a viral‐induced disease of myocardium, may lead to dilated cardiomyopathy and loss of heart function, and valvulitis leads to deformed heart valves and altered blood flow in rheumatic heart disease. Animal models recapitulating these diseases are important for understanding the human conditions. Cardiac myosin is a major autoantigen in heart tissue, and antibodies and T cells to cardiac myosin are evident in inflammatory heart diseases. This article is a practical guide to the induction and evaluation of experimental autoimmune myocarditis (EAM) in several mouse strains and the Lewis rat. Purification protocols for cardiac myosin and protocols for the induction of EAM by cardiac myosin and its myocarditis‐producing peptides, as well as coxsackievirus B3 (CVB3), are defined. Protocols for assessment of myocarditis and valvulitis in humans and animal models provide methods to define functional autoantibodies targeting cardiac myosin, β‐adrenergic, and muscarinic receptors, and their deposition in tissues. © 2026 Wiley Periodicals LLC. Basic Protocol 1 : Induction of EAM in mice by active immunization with cardiac myosin Alternate Protocol : Induction of EAM in mice by adoptive transfer of cardiac‐myosin‐stimulated T cells Basic Protocol 2 : Induction of EAM in rats by active immunization with cardiac myosin Support Protocol 1 : Purification of cardiac myosin Support Protocol 2 : Preparation of antigen/adjuvant emulsion by agitation for EAM induction in mice and rats Support Protocol 3 : Collection and histopathological assessment of mouse or rat hearts Support Protocol 4 : Immunostaining of rat heart tissue or cells for deposited antibody Basic Protocol 3 : Induction of myocarditis in mice by inoculation with coxsackievirus B3 (CVB3) from infectious cDNA clones Basic Protocol 4 : Induction of myocarditis and dilated cardiomyopathy in mice by inoculation with heart‐passaged coxsackievirus B3 (CVB3) Basic Protocol 5 : Induction of autoimmune valvular heart disease by inoculation with recombinant streptococcal M protein Basic Protocol 6 : Protein kinase A (PKA) assay of serum antibody signaling of the β‐adrenergic receptor with subsequent activation of PKA Basic Protocol 7 : Measurement of serum antibody titers against human cardiac myosin, human adrenergic β 1 and β 2 receptors, and muscarinic 2 receptor Basic Protocol 8 : Detection of antibodies against human cardiac myosin peptides in human serum

Abstract Background Wide-spread mast cell (MC)-associated symptoms and MC activation syndrome (MCAS) are often reported in patients with hypermobile Ehlers-Danlos syndrome (hEDS) and hypermobility spectrum disorders (HSD). The goal of this study was to develop a novel MC score based on 11 self-reported MC-related conditions with clinical and research utility to better understand MC symptoms in hEDS and HSD patients. Methods From November 1, 2019, to June 13, 2025, patients ( n =2,141) filled out an Intake Questionnaire at the Mayo Clinic Florida EDS Clinic that included 11 self-reported questions related to categories of MC-related conditions for a MC score ranging from 0/11 to 11/11. Based on the MC score distribution in hEDS and HSD patients, a MC score of 0-1 was considered a low MC score and ≥5 was considered a high MC score. Symptoms/comorbidities were compared between patients with high vs. low MC scores. Results From the 2,141 hEDS/HSD patients, 535 (25.0%) had a MC score ≥5 (Hi MC). MCAS-specific symptoms such as nausea and vomiting were reported more often in hEDS/HSD patients with a high vs. low MC score ( p <0.0001). Random clinical blood tryptase and urinary MC markers were not elevated in patients with high MC scores ( n =50/group), although high MC scores were found to significantly reduce urinary creatinine levels indicating that the protein used to normalize data was affected by MC activity. In contrast, random blood IgE, tryptase and major basic protein (MBP) by ELISA were increased in patients with high MC scores (e.g., IgE hEDS p =0.0004, HSD p =0.003). Of note, the percentage of patients reporting abuse or post-traumatic stress disorder was nearly doubled in patients with high vs. low MC scores (Abuse and PTSD: hEDS p < 0.0001; HSD p < 0.0001). Overall, 109/135 (80.7%) in hEDS and 129/135 (95.6%) in HSD reported more symptoms/comorbidities if they had a high MC score. Conclusions We found that hEDS/HSD patients with high MC scores self-reported more widespread symptoms/comorbidities and higher MC-related blood markers than patients with low MC scores indicating the utility of this tool to evaluate the level of widespread MC activity in hEDS, HSD and other patients.

Background Hypermobile Ehlers–Danlos syndrome (hEDS) and hypermobility spectrum disorders (HSDs) are heritable connective tissue disorders characterized by widespread fragile soft connective tissue affecting the skin, ligaments, joints, vasculature, and internal organs. Although hEDS and HSD are autosomal-dominant conditions and would be expected to display a 1:1 sex ratio, studies report higher prevalence in women. Objectives The purpose of this exploratory study was to determine whether self-reported sexual problems differed between females and males diagnosed with hEDS or HSD compared with controls with chronic pain but no hypermobility. Methods In this exploratory retrospective study, we examined 1,407 patients diagnosed with hEDS or HSD according to the 2017 diagnostic criteria for eight indicators of sexual problems based on a validated screening tool. Results Patients in each diagnosis primarily self-reported as White, non-Hispanic females (90%). Of the 1,407 patients who attended the EDS Clinic, 976 (69%) were diagnosed with HSD, 240 (17%) with hEDS, and 191 (14%) were chronic pain controls with neither diagnosis. For HSD, 937 (96%) were females vs. 39 (4%) males (24:1 females to males), while for hEDS, 210 (88%) were females vs. 30 (13%) males (7:1 females to males), and controls were 165 (86%) females vs. 26 (14%) males (6:1 females to males). Females with hEDS reported significantly higher rates of sexual issues than chronic pain controls, including sexual problems (69%, p = 0.018), problems with sexual interest (41%, p = 0.023), sexual pain (45%, p = 0.006), and orgasm difficulty (34%, p = 0.022) compared with males with hEDS or males or females with HSD. In contrast, males diagnosed with hEDS did not report any sexual problems over controls, and males and females diagnosed with HSD reported only one issue—more problems with sexual interest—compared with controls (females p = 0.019, males p = 0.018). However, the small number of males in this study limits conclusions that can be drawn for them. Conclusions This study is unique because we examine sex differences in sexual problems in patients with hEDS and HSD. Our findings indicate a higher percentage of sexual problems in females with hEDS than chronic pain controls without hypermobility, but this was not observed for females with HSD.

Background/Objective: It remains unknown whether patients with the more common forms of hypermobility carry an elevated risk for the development of intracranial/cervical artery abnormalities. The objective of this study was to determine the prevalence of unruptured intracranial aneurysms, spontaneous cervical artery dissections, and fibromuscular dysplasia in patients with hypermobile Ehlers–Danlos Syndrome (hEDS) and hypermobility spectrum disorders (HSD) who presented to an academic headache clinic. Methods: This is a retrospective cohort study. We used an electronic medical record to look for all patients seen at the Mayo Clinic Florida Headache Center and EDS Clinic between 2019 and 2025 with a diagnosis of hEDS or HSD and neuroimaging of both the intracranial and cervical arteries. Results: There were 103 patients who met the inclusion criteria. There was no statistically significant difference between hEDS and HSD patients in developing cerebral/cervical arterial anomalies. Of the sample, 95% of the hypermobile patients with abnormal neuroimaging also had migraine. A total of eleven (10.7%) patients (hEDS + HSD) were diagnosed with unruptured intracranial aneurysms. Trends included age less than 50 years, small aneurysms in the anterior circulation, and having migraine with aura. Five (4.8%) patients were diagnosed with spontaneous cervical artery dissection with trends for HSD, over the age of 50 years, vertebral artery involvement and a history of migraine without aura. Six (5.8%) patients were diagnosed with fibromuscular dysplasia with trends for HSD, over the age of 50 years, carotid artery involvement and a history of migraine with aura. Conclusions: This is the first study to identify that patients with the more common type of EDS, HSD and hEDS, and a possible concomitant history of migraine have a heightened risk for the development of unruptured intracranial aneurysms, spontaneous cervical artery dissections, and fibromuscular dysplasia. Our findings suggest the need for targeted screening with intracranial and extracranial arterial imaging for this unique patient population.

Abstract Background: Although hypermobile Ehlers-Danlos syndrome (hEDS) and hypermobility spectrum disorders (HSD) are inherited disorders expected to display a 1:1 sex ratio, most studies report a strong female dominance. This study analyzed sex differences in 122 self-reported symptoms and comorbidities in patients diagnosed with hEDS or HSD using the 2017 criteria. Methods: Self-reported data was obtained from November 1, 2019, to April 25, 2025, ( n =2,451) from an Intake Questionnaire of adult (≤18 years old) patients diagnosed with hEDS or HSD at the EDS Clinic at Mayo Clinic Florida and analyzed by sex. Results: We found that 90.6% ( n =575) of hEDS patients were female and 9.4% ( n =60) were male, with a sex ratio of 9.6:1 female-to-male, while 95.2% ( n =1,728) of HSD patients were female and 4.8% ( n =88) were male, with a sex ratio of 19.6:1 female-to-male. Females were older than males: hEDS 35 vs. 28 years of age ( p <0.001), HSD 34 vs. 31 years of age ( p =0.004). Overall, females self-reported more symptoms/comorbidities than males: hEDS 31/122 (25.4%), HSD 59/122 (48.4%). In contrast, only 5/122 (4.1%) symptoms/comorbidities were self-reported more often in males including attention deficit disorder/attention deficit hyperactivity disorder, delay in developmental milestones, snoring, autism spectrum disorder, and obstructive sleep apnea. Females with HSD had more mast cell-related symptoms (i.e., hives p <0.001) which were reflected in higher mast cell scores than males ( p <0.001). Patients with higher mast cell scores also had higher serum levels of total IgE ( p =0.029). More females with HSD were diagnosed with fibromyalgia ( p <0.001) and reported symptoms associated with autonomic dysfunction than males. Aside from abuse, which was higher in females (hEDS p =0.039, HSD p <0.001), few sex differences were reported for psychological symptoms/comorbidities. In support for the idea that elevated mast cell activity in females may lead to extracellular matrix remodeling that promotes hypermobility, females with hEDS/HSD had greater serum collagen-4α1 ( p <0.0001) and fibronectin ( p =0.015) than males by ELISA. Conclusions: Females with hEDS and HSD report a higher burden of symptoms/comorbidities than males, providing a possible explanation for fewer males being reported in demographic data. Sex differences in symptoms/comorbidities may reflect sex differences in pathogenic drivers of disease.

Coxsackievirus B3 (CVB3) is a picornavirus that causes systemic inflammatory diseases including myocarditis, pericarditis, pancreatitis, and meningoencephalitis. We have previously reported that CVB3 induces mitochondrial fission and mitophagy while inhibiting lysosomal degradation by blocking autophagosome-lysosome fusion. This promotes the release of virus-laden mitophagosomes from host cells as infectious extracellular vesicles (EVs), enabling non-lytic viral egress. Transient receptor potential vanilloid 1 (TRPV1), a heat and capsaicin-sensitive cation channel, regulates mitochondrial dynamics by inducing mitochondrial membrane depolarization and fission. In this study, we found that TRPV1 activation by capsaicin dramatically enhances CVB3 egress from host cells via EVs. Released EVs revealed increased levels of viral capsid protein VP1, mitochondrial protein TOM70, and fission protein phospho-DRP1. Moreover, these EVs were enriched in heat shock protein HSP70, suggesting its role in facilitating infectious EV release from cells. Furthermore, TRPV1 inhibition with capsazepine and SB-366791 significantly reduced viral infection in vitro. Our in vivo studies also found that SB-366791 significantly mitigates pancreatic damage and reduces viral titers in a mouse model of CVB3 pancreatitis. Given the lack of understanding regarding factors that contribute to diverse clinical manifestations of CVB3, our study highlights capsaicin and TRPV1 as potential exacerbating factors that facilitate CVB3 dissemination via mitophagy-derived EVs.