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1.
Clin Auton Res ; 33(6): 767-775, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37943335

RESUMO

PURPOSE: Acute decompensated heart failure (ADHF) is associated with inflammation, oxidative stress, and excess sympathetic drive. It is unknown whether neuromodulation would improve inflammation and oxidative stress in acute heart failure. We, therefore, performed this proof-of-concept study to evaluate the effects of neuromodulation using noninvasive low-level tragus stimulation on inflammation and oxidative stress in ADHF. METHODS: Nineteen patients with ejection fraction < 40% were randomized to neuromodulation 4 h twice daily (6-10 a.m. and 6-10 p.m.) (n = 8) or sham stimulation (n = 11) during hospital admission. All patients received standard-of-care treatment. Blood samples were collected at admission and discharge. Serum cytokines were assayed using standard immunosorbent techniques. Reactive oxygen species inducibility from cultured coronary endothelial cells exposed to patient sera was determined using a dihydrodichlorofluorescein probe test (expressed as fluorescein units). RESULTS: Compared to sham stimulation, neuromodulation was associated with a significant reduction of circulating serum interleukin-6 levels (-78% vs. -9%; p = 0.012). Similarly, neuromodulation led to a reduction of endothelial cell oxidative stress in the neuromodulation group (1363 units to 978 units, p = 0.003) compared to sham stimulation (1146 units to 1083 units, p = 0.094). No significant differences in heart rate, blood pressure, or renal function were noted between the two groups. CONCLUSION: In this proof-of-concept pilot study, in acute decompensated heart failure, neuromodulation was feasible and safe and was associated with a reduction in systemic inflammation and attenuation of coronary endothelial cellular oxidative stress. CLINICAL TRIAL REGISTRATION: NCT02898181.


Assuntos
Células Endoteliais , Insuficiência Cardíaca , Humanos , Projetos Piloto , Insuficiência Cardíaca/terapia , Inflamação/terapia , Estresse Oxidativo
2.
J Infect Dis ; 218(2): 324-335, 2018 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-29236994

RESUMO

Acute rheumatic fever and rheumatic heart disease (ARF/RHD) have long been described as autoimmune sequelae of Streptococcus pyogenes or group A streptococcal (GAS) infection. Both antibody and T-cell responses against immunodominant GAS virulence factors, including M protein, cross-react with host tissue proteins, triggering an inflammatory response leading to permanent heart damage. However, in some ARF/RHD-endemic regions, throat carriage of GAS is low. Because Streptococcus dysgalactiae subspecies equisimilis organisms, also known as ß-hemolytic group C streptococci and group G streptococci (GGS), also express M protein, we postulated that streptococci other than GAS may have the potential to initiate or exacerbate ARF/RHD. Using a model initially developed to investigate the uniquely human disease of ARF/RHD, we have discovered that GGS causes interleukin 17A/interferon γ-induced myocarditis and valvulitis, hallmarks of ARF/RHD. Remarkably the histological, immunological, and functional changes in the hearts of rats exposed to GGS are identical to those exposed to GAS. Furthermore, antibody cross-reactivity to cardiac myosin was comparable in both GGS- and GAS-exposed animals, providing additional evidence that GGS can induce and/or exacerbate ARF/RHD.


Assuntos
Doenças Autoimunes/etiologia , Interferon gama/metabolismo , Interleucina-17/metabolismo , Cardiopatia Reumática/etiologia , Infecções Estreptocócicas/patologia , Streptococcus/imunologia , Animais , Antígenos de Bactérias/imunologia , Doenças Autoimunes/microbiologia , Doenças Autoimunes/fisiopatologia , Proteínas da Membrana Bacteriana Externa/imunologia , Proteínas de Transporte/imunologia , Modelos Animais de Doenças , Feminino , Doenças das Valvas Cardíacas/etiologia , Doenças das Valvas Cardíacas/microbiologia , Doenças das Valvas Cardíacas/fisiopatologia , Miocardite/etiologia , Miocardite/microbiologia , Miocardite/fisiopatologia , Ratos Endogâmicos Lew , Cardiopatia Reumática/microbiologia , Cardiopatia Reumática/fisiopatologia , Streptococcus/patogenicidade
3.
J Card Fail ; 22(7): 520-8, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26941007

RESUMO

BACKGROUND: Host autoimmune activity in myocarditis has been proposed to play a role in development of cardiac disease, but evidence of autoimmunity and relationship to outcomes have not been evaluated in pediatric myocarditis. METHODS: We performed a multi-institutional study of children with clinical myocarditis. Newly diagnosed patients were followed for up to 12 months and previously diagnosed patients at a single follow-up for serum levels of autoantibodies to human cardiac myosin, beta-adrenergic receptors 1 and 2, muscarinic-2 receptors, and antibody-mediated protein kinase A (PKA) activation in heart cells in culture. Results were compared with those of healthy control children. RESULTS: Both previously diagnosed patient at follow-up (P = .0061) and newly diagnosed patients at presentation (P = .0127) had elevated cardiac myosin antibodies compared with control subjects. Antibody levels were not associated with recovery status at follow-up in either group. PKA activation was higher at presentation in the newly diagnosed patients who did not recovery normal function (P = .042). CONCLUSIONS: Children with myocarditis have evidence of autoantibodies against human cardiac myosin at diagnosis and follow-up compared with control subjects. Differences in antibody-mediated cell signaling may contribute to differences in patient outcomes, as suggested by elevated antibody-mediated PKA activation in heart cells by the serum from nonrecovered patients.


Assuntos
Autoanticorpos/imunologia , Autoimunidade , Miosinas Cardíacas/imunologia , Proteínas Quinases Dependentes de AMP Cíclico/imunologia , Miocardite/imunologia , Miócitos Cardíacos/imunologia , Autoanticorpos/sangue , Criança , Pré-Escolar , Proteínas Quinases Dependentes de AMP Cíclico/análise , Coração/diagnóstico por imagem , Coração/fisiopatologia , Humanos , Lactente , Miocardite/sangue , Miocardite/diagnóstico por imagem , Miócitos Cardíacos/química
4.
J Immunol ; 192(9): 4074-82, 2014 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-24670798

RESUMO

Structural congenital heart disease (CHD) has not previously been linked to autoimmunity. In our study, we developed an autoimmune model of structural CHD that resembles hypoplastic left heart syndrome (HLHS), a life-threatening CHD primarily affecting the left ventricle. Because cardiac myosin (CM) is a dominant autoantigen in autoimmune heart disease, we hypothesized that immunization with CM might lead to transplacental passage of maternal autoantibodies and a prenatal HLHS phenotype in exposed fetuses. Elevated anti-CM autoantibodies in maternal and fetal sera, as well as IgG reactivity in fetal myocardium, were correlated with structural CHD that included diminished left ventricular cavity dimensions in the affected progeny. Further, fetuses that developed a marked HLHS phenotype had elevated serum titers of anti-ß-adrenergic receptor Abs, as well as increased protein kinase A activity, suggesting a potential mechanism for the observed pathological changes. Our maternal-fetal model presents a new concept linking autoimmunity against CM and cardiomyocyte proliferation with cardinal features of HLHS. To our knowledge, this report shows the first evidence in support of a novel immune-mediated mechanism for pathogenesis of structural CHD that may have implications in its future diagnosis and treatment.


Assuntos
Autoimunidade/imunologia , Miosinas Cardíacas/imunologia , Síndrome do Coração Esquerdo Hipoplásico/imunologia , Animais , Autoanticorpos/imunologia , Western Blotting , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Cardiopatias Congênitas/imunologia , Cardiopatias Congênitas/patologia , Síndrome do Coração Esquerdo Hipoplásico/patologia , Imuno-Histoquímica , Ratos , Ratos Endogâmicos Lew
5.
J Immunol ; 191(11): 5524-41, 2013 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-24184556

RESUMO

How autoantibodies target the brain and lead to disease in disorders such as Sydenham chorea (SC) is not known. SC is characterized by autoantibodies against the brain and is the main neurologic manifestation of streptococcal-induced rheumatic fever. Previously, our novel SC-derived mAb 24.3.1 was found to recognize streptococcal and brain Ags. To investigate in vivo targets of human mAb 24.3.1, VH/VL genes were expressed in B cells of transgenic (Tg) mice as functional chimeric human VH 24.3.1-mouse C-region IgG1(a) autoantibody. Chimeric human-mouse IgG1(a) autoantibody colocalized with tyrosine hydroxylase in the basal ganglia within dopaminergic neurons in vivo in VH 24.3.1 Tg mice. Both human mAb 24.3.1 and IgG1(a) in Tg sera were found to react with human dopamine D2 receptor (D2R). Reactivity of chorea-derived mAb 24.3.1 or SC IgG with D2R was confirmed by dose-dependent inhibitory signaling of D2R as a potential consequence of targeting dopaminergic neurons, reaction with surface-exposed FLAG epitope-tagged D2R, and blocking of Ab reactivity by an extracellular D2R peptide. IgG from SC and a related subset of streptococcal-associated behavioral disorders called "pediatric autoimmune neuropsychiatric disorder associated with streptococci" (PANDAS) with small choreiform movements reacted in ELISA with D2R. Reaction with FLAG-tagged D2R distinguished SC from PANDAS, whereas sera from both SC and PANDAS induced inhibitory signaling of D2R on transfected cells comparably to dopamine. In this study, we define a mechanism by which the brain may be altered by Ab in movement and behavioral disorders.


Assuntos
Coreia/imunologia , Neurônios Dopaminérgicos/metabolismo , Receptores de Dopamina D2/metabolismo , Febre Reumática/imunologia , Infecções Estreptocócicas/imunologia , Animais , Antígenos de Bactérias/imunologia , Autoanticorpos/genética , Autoanticorpos/metabolismo , Gânglios da Base/patologia , Criança , Coreia/etiologia , Reações Cruzadas , Dopamina/metabolismo , Neurônios Dopaminérgicos/imunologia , Gangliosídeo G(M1)/análogos & derivados , Gangliosídeo G(M1)/imunologia , Células HEK293 , Humanos , Imunoglobulina G/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptores de Dopamina D2/genética , Proteínas Recombinantes de Fusão/genética , Febre Reumática/etiologia , Transdução de Sinais , Infecções Estreptocócicas/complicações , Transgenes/genética
7.
J Biol Chem ; 288(42): 30734-30741, 2013 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-24043632

RESUMO

Functional autoantibodies to the autonomic receptors are increasingly recognized in the pathophysiology of cardiovascular diseases. To date, no human activating monoclonal autoantibodies to these receptors have been available. In this study, we describe for the first time a ß2-adrenergic receptor (ß2AR)-activating monoclonal autoantibody (C5F2) produced from the lymphocytes of a patient with idiopathic postural hypotension. C5F2, an IgG3 isotype, recognizes an epitope in the N terminus of the second extracellular loop (ECL2) of ß2AR. Surface plasmon resonance analysis revealed high binding affinity for the ß2AR ECL2 peptide. Immunoblotting and immunofluorescence demonstrated specific binding to ß2AR in H9c2 cardiomyocytes, CHO cells expressing human ß2AR, and rat aorta. C5F2 stimulated cyclic AMP production in ß2AR-transfected CHO cells and induced potent dilation of isolated rat cremaster arterioles, both of which were specifically blocked by the ß2AR-selective antagonist ICI-118551 and by the ß2AR ECL2 peptide. This monoclonal antibody demonstrated sufficient activity to produce postural hypotension in its host. Its availability provides a unique opportunity to identify previously unrecognized causes and new pharmacological management of postural hypotension and other cardiovascular diseases.


Assuntos
Anticorpos Monoclonais/imunologia , Autoanticorpos/imunologia , Hipotensão Ortostática/imunologia , Hipotensão Ortostática/fisiopatologia , Imunoglobulina G/imunologia , Receptores Adrenérgicos beta 2/imunologia , Vasodilatadores/imunologia , Antagonistas Adrenérgicos beta/farmacologia , Animais , Anticorpos Monoclonais/sangue , Anticorpos Monoclonais/farmacologia , Aorta/imunologia , Aorta/metabolismo , Aorta/patologia , Aorta/fisiopatologia , Arteríolas/metabolismo , Arteríolas/patologia , Arteríolas/fisiopatologia , Autoanticorpos/sangue , Autoanticorpos/farmacologia , Células CHO , Cricetinae , Cricetulus , Humanos , Hipotensão Ortostática/sangue , Hipotensão Ortostática/genética , Hipotensão Ortostática/patologia , Imunoglobulina G/sangue , Imunoglobulina G/farmacologia , Masculino , Miócitos Cardíacos/imunologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Peptídeos/imunologia , Peptídeos/farmacologia , Propanolaminas/farmacologia , Ratos , Receptores Adrenérgicos beta 2/sangue , Receptores Adrenérgicos beta 2/genética , Ressonância de Plasmônio de Superfície , Vasodilatadores/sangue , Vasodilatadores/farmacologia
8.
Am J Physiol Heart Circ Physiol ; 306(3): H422-8, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24271491

RESUMO

Previous studies demonstrated burst pacing and intravenous infusion of ACh induced sustained atrial tachycardia when rabbits were immunized to produce ß2-adrenergic receptor (ß2AR)-activating autoantibodies. The objective of this study was to examine the arrhythmogenic effect of ß1-adrenergic receptor (ß1AR)-activating autoantibodies in the rabbit. Eight New Zealand white rabbits were immunized with a ß1AR second extracellular loop peptide to raise ß1AR antibody titers. A catheter-based electrophysiological study was performed on anesthetized rabbits before and after immunization. Arrhythmia occurrence was determined in response to burst pacing before and after ACh infusion in incremental concentrations of 10 µM, 100 µM, and 1 mM. The baseline sinus heart rate before and after immunization averaged 149 ± 17 per min and 169 ± 16 per min, respectively (P < 0.05). In the preimmune studies, there were five sustained (≥10 s) arrhythmias in 32 induction attempts, which occurred in only four of eight rabbits. In the postimmune studies, there were 22 sustained arrhythmias in 32 induction attempts, which occurred in all eight rabbits (P < 0.0001 for the independent effect of immunization). Of the 22 sustained arrhythmias postimmunization, 15 were sinus tachycardia compared with only two before immunization (P < 0.01 for the independent effect of immunization). Postimmune (but not preimmune) rabbit sera demonstrated specific binding to ß1AR and induced significant ß1AR activation in transfected cells in vitro. No cross-reactivity with ß2AR was observed. In conclusion, in contrast with rabbits with ß2AR-activating autoantibodies that demonstrate predominantly atrial tachycardias, enhanced autoantibody activation of ß1AR in the rabbit leads to tachyarrhythmias mainly in the form of sustained sinus tachycardia.


Assuntos
Arritmias Cardíacas/imunologia , Autoanticorpos/metabolismo , Receptores Adrenérgicos beta 1/imunologia , Acetilcolina/farmacologia , Animais , Arritmias Cardíacas/metabolismo , Autoanticorpos/imunologia , Frequência Cardíaca , Coelhos , Receptores Adrenérgicos beta 1/metabolismo
9.
Brain Behav Immun ; 38: 249-62, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24561489

RESUMO

Group A ß-hemolytic streptococcal (GAS) infection is associated with a spectrum of neuropsychiatric disorders. The leading hypothesis regarding this association proposes that a GAS infection induces the production of auto-antibodies, which cross-react with neuronal determinants in the brain through the process of molecular mimicry. We have recently shown that exposure of rats to GAS antigen leads to the production of anti-neuronal antibodies concomitant with the development of behavioral alterations. The present study tested the causal role of the antibodies by assessing the behavior of naïve rats following passive transfer of purified antibodies from GAS-exposed rats. Immunoglobulin G (IgG) purified from the sera of GAS-exposed rats was infused directly into the striatum of naïve rats over a 21-day period. Their behavior in the induced-grooming, marble burying, food manipulation and beam walking assays was compared to that of naïve rats infused with IgG purified from adjuvant-exposed rats as well as of naïve rats. The pattern of in vivo antibody deposition in rat brain was evaluated using immunofluorescence and colocalization. Infusion of IgG from GAS-exposed rats to naïve rats led to behavioral and motor alterations partially mimicking those seen in GAS-exposed rats. IgG from GAS-exposed rats reacted with D1 and D2 dopamine receptors and 5HT-2A and 5HT-2C serotonin receptors in vitro. In vivo, IgG deposits in the striatum of infused rats colocalized with specific brain proteins such as dopamine receptors, the serotonin transporter and other neuronal proteins. Our results demonstrate the potential pathogenic role of autoantibodies produced following exposure to GAS in the induction of behavioral and motor alterations, and support a causal role for autoantibodies in GAS-related neuropsychiatric disorders.


Assuntos
Corpo Estriado/imunologia , Imunoglobulina G/imunologia , Streptococcus pyogenes/imunologia , Animais , Comportamento Animal , Corpo Estriado/metabolismo , Masculino , Atividade Motora , Ratos , Ratos Endogâmicos Lew , Receptores Dopaminérgicos/metabolismo , Receptores de Serotonina/metabolismo
10.
Infect Dis Obstet Gynecol ; 2014: 639141, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25210420

RESUMO

OBJECTIVES: To report the pharyngeal colonization rate of ß-hemolytic streptococci and changes in the value of antistreptolysin O (ASO) and anti-DNase B serology titers during pregnancy. METHODS: Healthy pregnant women were recruited and blood was drawn in each trimester. The upper limit of normal (ULN) values for ASO and anti-DNase B was calculated for each trimester. Throat swabs were collected for culture and positive cultures were further assessed for the identification of serogroup of the isolated ß-hemolytic streptococcus. RESULTS: Out of a total of 126 pregnant women, 34.1% had positive throat cultures. Group C and group G strains were isolated in 18.2% of throat cultures while group F was detected in 13.5% of cases. The rate of colonization with GAS was 1.6%. There was an overall drop in ASO titer during pregnancy while anti-DNase B titers remained relatively unchanged. ULN values of 164(IU), 157(IU), and 156(IU) were calculated for ASO at the first, second, and third trimesters, respectively. Based on the ULN values, 28.6% of patients had recent streptococcal exposure. CONCLUSIONS: These results show that pregnant women act as a reservoir for spreading potentially immunogenic (groups C and G) and disease producing (group F) virulent strains of streptococci.


Assuntos
Portador Sadio/microbiologia , Faringite/microbiologia , Complicações Infecciosas na Gravidez/microbiologia , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/isolamento & purificação , Adulto , Portador Sadio/epidemiologia , Feminino , Humanos , Faringite/epidemiologia , Faringe/microbiologia , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Infecções Estreptocócicas/epidemiologia , Estados Unidos/epidemiologia , Adulto Jovem
11.
JCI Insight ; 2024 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-39325550

RESUMO

Despite growing recognition, neuropsychiatric diseases associated with infections are a major unsolved problem worldwide. Group A streptococcal (GAS) infections can cause autoimmune sequelae characterized by movement disorders, such as Sydenham chorea (SC), and neuropsychiatric disorders. The molecular mechanisms underlying these diseases are not fully understood. Our previous work demonstrates that autoantibodies (AAbs) can target dopaminergic neurons and increase dopamine receptor D2 (D2R) signaling. However, AAb influence on dopamine receptor D1 (D1R) activity is underexplored. We found evidence that suggests GAS-induced cross-reactive AAbs promote autoimmune encephalitis of the basal ganglia (BGE), a region of high dopamine receptor density. Here, we report a new mechanism whereby neuropsychiatric syndromes are distinguished from movement disorders by differences in D1R and D2R AAb titers, signaling, receiver operating characteristic (ROC) curves, and immunoreactivity with D1R and D2R autoreactive epitopes. D1R AAb signaling was observed through patient serum AAbs and novel patient-derived mAbs, which induced both D1R G protein- and -arrestin transduced signals. Furthermore, patient AAbs and mAbs enhanced D1R signaling mechanisms mediated by the neurotransmitter dopamine. Our findings suggest that AAb-mediated D1R signaling may contribute to the pathogenesis of neuropsychiatric sequelae and inform new options for diagnosis and treatment of GAS sequelae and related disorders. .

12.
J Immunol ; 187(2): 1023-30, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21677143

RESUMO

Chronic allograft vasculopathy (CAV) contributes to heart transplant failure, yet its pathogenesis is incompletely understood. Although cellular and humoral alloimmunity are accepted pathogenic mediators, animal models suggest that T cells and Abs reactive to graft-expressed autoantigens, including cardiac myosin (CM), could participate. To test the relationship between CAV and anti-CM autoimmunity in humans, we performed a cross-sectional study of 72 heart transplant recipients: 40 with CAV and 32 without. Sera from 65% of patients with CAV contained anti-CM Abs, whereas <10% contained Abs to other autoantigens (p < 0.05), and only 18% contained anti-HLA Abs (p < 0.05 versus anti-CM). In contrast, 13% of sera from patients without CAV contained anti-CM Abs (p < 0.05; odds ratio [OR], associating CAV with anti-CM Ab = 13, 95% confidence interval [CI] 3.79-44.6). Multivariable analysis confirmed the association to be independent of time posttransplant and the presence of anti-HLA Abs (OR = 28, 95% CI 5.77-133.56). PBMCs from patients with CAV responded more frequently to, and to a broader array of, CM-derived peptides than those without CAV (p = 0.01). Detection of either CM-peptide-reactive T cells or anti-CM Abs was highly and independently indicative of CAV (OR = 45, 95% CI 4.04-500.69). Our data suggest detection of anti-CM immunity could be used as a biomarker for outcome in heart transplantation recipients and support the need for further studies to assess whether anti-CM immunity is a pathogenic mediator of CAV.


Assuntos
Miosinas Cardíacas/imunologia , Endotélio Vascular/imunologia , Endotélio Vascular/patologia , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/patologia , Transplante de Coração/imunologia , Transplante de Coração/patologia , Idoso , Sequência de Aminoácidos , Animais , Autoanticorpos/biossíntese , Biomarcadores/sangue , Doença Crônica , Complemento C4b/imunologia , Estudos Transversais , Endotélio Vascular/metabolismo , Feminino , Rejeição de Enxerto/diagnóstico , Antígenos HLA/imunologia , Humanos , Macrófagos/imunologia , Macrófagos/patologia , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Infiltração de Neutrófilos/imunologia , Fragmentos de Peptídeos/imunologia , Projetos Piloto , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Subpopulações de Linfócitos T/patologia
13.
Vaccines (Basel) ; 11(9)2023 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-37766180

RESUMO

Group A streptococcus (GAS) is a global pathogen associated with significant morbidity and mortality for which there is currently no licensed vaccine. Vaccine development has been slow, mostly due to safety concerns regarding streptococcal antigens associated with autoimmunity and related complications. For a GAS vaccine to be safe, it must be ensured that the antigens used in the vaccine do not elicit an antibody response that can cross-react with host tissues. In this study, we evaluated the safety of our GAS vaccine candidate called VaxiStrep in New Zealand White rabbits. VaxiStrep is a recombinant fusion protein comprised of streptococcal pyrogenic exotoxin A (SpeA) and exotoxin B (SpeB), also known as erythrogenic toxins, adsorbed to an aluminum adjuvant. The vaccine elicited a robust immune response against the two toxins in the rabbits without any adverse events or toxicity. No signs of autoimmune pathology were detected in the rabbits' brains, hearts, and kidneys via immunohistochemistry, and serum antibodies did not cross-react with cardiac or neuronal tissue proteins associated with rheumatic heart disease or Sydenham chorea (SC). This study further confirms that VaxiStrep does not elicit autoantibodies and is safe to be tested in a first-in-human trial.

14.
Res Sq ; 2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37790298

RESUMO

Purpose: Acute decompensated heart failure is associated with inflammation, oxidative stress, and excess sympathetic drive. It is unknown if neuromodulation would improve inflammation and oxidative stress in acute heart failure. We, therefore, performed this proof-of-concept study to evaluate the effects of neuromodulation using noninvasive low-level Tragus stimulation on inflammation and oxidative stress in ADHF. Methods: 19 patients with ejection fraction < 40% were randomized to neuromodulation- 4 hours twice daily (6 AM-10 AM and 6 PM-10 PM) (n = 8) or sham stimulation (n = 11) during hospital admission. All patients received standard-of-care treatment. Blood samples were collected at admission and discharge. Serum cytokines were assayed using standard immunosorbent techniques. Reactive oxygen species inducibility from cultured coronary endothelial cells exposed to patient sera was determined using dihydrodichlorofluorescein probe test (expressed as fluorescein units). Results: Compared to sham stimulation, neuromodulation was associated with a significant reduction of circulating serum Interleukin-6 levels (-78% vs -9%; p = 0.012). Similarly, neuromodulation led to reduction of endothelial cell oxidative stress, in the neuromodulation group (1363 units to 978 units, p = 0.003) compared to sham stimulation (1146 units to 1083 units, p = 0.094). No significant difference in heart rate, blood pressure or renal function were noted between the two groups. Conclusion: In this proof-of-concept pilot study, in acute systolic heart failure, neuromodulation was feasible and safe and was associated with a reduction in systemic inflammation and attenuation of cellular oxidative stress. Clinical trial: NCT02898181.

16.
BMJ Glob Health ; 8(Suppl 9)2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37914183

RESUMO

Secondary prevention of acute rheumatic fever (ARF) and rheumatic heart disease (RHD) involves continuous antimicrobial prophylaxis among affected individuals and is recognised as a cornerstone of public health programmes that address these conditions. However, several important scientific issues around the secondary prevention paradigm remain unresolved. This report details research priorities for secondary prevention that were developed as part of a workshop convened by the US National Heart, Lung, and Blood Institute in November 2021. These span basic, translational, clinical and population science research disciplines and are built on four pillars. First, we need a better understanding of RHD epidemiology to guide programmes, policies, and clinical and public health practice. Second, we need better strategies to find and diagnose people affected by ARF and RHD. Third, we urgently need better tools to manage acute RF and slow the progression of RHD. Fourth, new and existing technologies for these conditions need to be better integrated into healthcare systems. We intend for this document to be a reference point for research organisations and research sponsors interested in contributing to the growing scientific community focused on RHD prevention and control.


Assuntos
Febre Reumática , Cardiopatia Reumática , Estados Unidos , Humanos , Febre Reumática/prevenção & controle , Febre Reumática/complicações , Febre Reumática/diagnóstico , Cardiopatia Reumática/prevenção & controle , Cardiopatia Reumática/diagnóstico , Prevenção Secundária , National Heart, Lung, and Blood Institute (U.S.) , Projetos de Pesquisa
17.
BMJ Glob Health ; 8(Suppl 9)2023 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-38164699

RESUMO

Streptococcus pyogenes, also known as group A streptococcus (StrepA), is a bacterium that causes a range of human diseases, including pharyngitis, impetigo, invasive infections, and post-infection immune sequelae such as rheumatic fever and rheumatic heart disease. StrepA infections cause some of the highest burden of disease and death in mostly young populations in low-resource settings. Despite decades of effort, there is still no licensed StrepA vaccine, which if developed, could be a cost-effective way to reduce the incidence of disease. Several challenges, including technical and regulatory hurdles, safety concerns and a lack of investment have hindered StrepA vaccine development. Barriers to developing a StrepA vaccine must be overcome in the future by prioritising key areas of research including greater understanding of StrepA immunobiology and autoimmunity risk, better animal models that mimic human disease, expanding the StrepA vaccine pipeline and supporting vaccine clinical trials. The development of a StrepA vaccine is a complex and challenging process that requires significant resources and investment. Given the global burden of StrepA infections and the potential for a vaccine to save lives and livelihoods, StrepA vaccine development is an area of research that deserves considerable support. This report summarises the findings of the Primordial Prevention Working Group-VAX, which was convened in November 2021 by the National Heart, Lung, and Blood Institute. The focus of this report is to identify research gaps within the current StrepA vaccine landscape and find opportunities and develop priorities to promote the rapid and successful advancement of StrepA vaccines.


Assuntos
Febre Reumática , Cardiopatia Reumática , Infecções Estreptocócicas , Vacinas Estreptocócicas , Animais , Humanos , Febre Reumática/prevenção & controle , Febre Reumática/tratamento farmacológico , Febre Reumática/epidemiologia , Cardiopatia Reumática/prevenção & controle , Cardiopatia Reumática/complicações , Cardiopatia Reumática/tratamento farmacológico , Infecções Estreptocócicas/prevenção & controle , Infecções Estreptocócicas/complicações , Infecções Estreptocócicas/epidemiologia , Streptococcus pyogenes , Vacinas Estreptocócicas/uso terapêutico , Pulmão
18.
BMJ Glob Health ; 8(Suppl 9)2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37914182

RESUMO

Although entirely preventable, rheumatic heart disease (RHD), a disease of poverty and social disadvantage resulting in high morbidity and mortality, remains an ever-present burden in low-income and middle-income countries (LMICs) and rural, remote, marginalised and disenfranchised populations within high-income countries. In late 2021, the National Heart, Lung, and Blood Institute convened a workshop to explore the current state of science, to identify basic science and clinical research priorities to support RHD eradication efforts worldwide. This was done through the inclusion of multidisciplinary global experts, including cardiovascular and non-cardiovascular specialists as well as health policy and health economics experts, many of whom also represented or closely worked with patient-family organisations and local governments. This report summarises findings from one of the four working groups, the Tertiary Prevention Working Group, that was charged with assessing the management of late complications of RHD, including surgical interventions for patients with RHD. Due to the high prevalence of RHD in LMICs, particular emphasis was made on gaining a better understanding of needs in the field from the perspectives of the patient, community, provider, health system and policy-maker. We outline priorities to support the development, and implementation of accessible, affordable and sustainable interventions in low-resource settings to manage RHD and related complications. These priorities and other interventions need to be adapted to and driven by local contexts and integrated into health systems to best meet the needs of local communities.


Assuntos
Cardiopatia Reumática , Estados Unidos , Humanos , Cardiopatia Reumática/epidemiologia , Cardiopatia Reumática/prevenção & controle , Prevenção Terciária , National Heart, Lung, and Blood Institute (U.S.)
19.
Curr Opin Rheumatol ; 24(4): 408-16, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22617826

RESUMO

PURPOSE OF REVIEW: To give an overview of the current hypotheses of the pathogenesis of rheumatic fever and group A streptococcal autoimmune sequelae of the heart valve and brain. RECENT FINDINGS: Human monoclonal antibodies (mAbs) derived from rheumatic heart disease have provided evidence for crossreactive autoantibodies that target the dominant group A streptococcal epitope of the group A carbohydrate, N-acetyl-beta-D-glucosamine (GlcNAc), and heart valve endothelium, laminin and laminar basement membrane. T cells in peripheral blood and in rheumatic heart valves revealed the presence of T cells crossreactive with streptococcal M protein and cardiac myosin. For initiation of disease, evidence suggests a two-hit hypothesis for antibody attack on the valve endothelium with subsequent extravasation of T cells through activated endothelium into the valve to form granulomatous lesions and Aschoff bodies. Autoantibodies against the group A streptococcal carbohydrate epitope GlcNAc and cardiac myosin and its peptides appear during progression of rheumatic heart disease. However, autoantibodies against collagen that are not crossreactive may form because of the release of collagen from damaged valve or to responses to collagen bound in vitro by certain serotypes of streptococci. In Sydenham chorea, human mAbs derived from disease target the group A carbohydrate epitope GlcNAc and gangliosides and dopamine receptors found on the surface of neuronal cells in the brain. Human mAbs and autoantibodies in Sydenham chorea were found to signal neuronal cells and activate calcium calmodulin-dependent protein kinase II (CaMKII) in neuronal cells and recognize the intracellular protein biomarker tubulin. SUMMARY: To summarize, pathogenic mechanisms of crossreactive autoantibodies which target the valve in rheumatic heart disease and the neuronal cell in Sydenham chorea share a common streptococcal epitope GlcNAc and target intracellular biomarkers of disease including cardiac myosin in the myocardium and tubulin, a protein abundant in the brain. However, intracellular antigens are not believed to be the basis for disease. The theme of molecular mimicry in streptococcal autoimmune sequelae is the recognition of targeted intracellular biomarker antigens such as cardiac myosin and brain tubulin, while targeting extracellular membrane antigens such as laminin on the valve surface endothelium or lysoganglioside and dopamine receptors in the brain. Antibody binding to these cell surface antigens may lead to valve damage in rheumatic heart disease or neuropsychiatric behaviors and involuntary movements in Sydenham chorea.


Assuntos
Cardiopatia Reumática/imunologia , Streptococcus pyogenes/imunologia , Antígenos de Bactérias/imunologia , Autoanticorpos/imunologia , Autoimunidade , Coreia/imunologia , Coreia/microbiologia , Reações Cruzadas/imunologia , Humanos , Mimetismo Molecular/imunologia , Neurônios/imunologia
20.
Front Cardiovasc Med ; 9: 919700, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36815140

RESUMO

Antecedent group A streptococcal pharyngitis is a well-established cause of acute rheumatic fever (ARF) where rheumatic valvular heart disease (RHD) and Sydenham chorea (SC) are major manifestations. In ARF, crossreactive antibodies and T cells respond to streptococcal antigens, group A carbohydrate, N-acetyl-ß-D-glucosamine (GlcNAc), and M protein, respectively, and through molecular mimicry target heart and brain tissues. In this translational human study, we further address our hypothesis regarding specific pathogenic humoral and cellular immune mechanisms leading to streptococcal sequelae in a small pilot study. The aims of the study were to (1) better understand specific mechanisms of pathogenesis in ARF, (2) identify a potential early biomarker of ARF, (3) determine immunoglobulin G (IgG) subclasses directed against GlcNAc, the immunodominant epitope of the group A carbohydrate, by reaction of ARF serum IgG with GlcNAc, M protein, and human neuronal cells (SK-N-SH), and (4) determine IgG subclasses deposited on heart tissues from RHD. In 10 pediatric patients with RHD and 6 pediatric patients with SC, the serum IgG2 subclass reacted significantly with GlcNAc, and distinguished ARF from 7 pediatric patients with uncomplicated pharyngitis. Three pediatric patients who demonstrated only polymigrating arthritis, a major manifestation of ARF and part of the Jones criteria for diagnosis, lacked the elevated IgG2 subclass GlcNAc-specific reactivity. In SC, the GlcNAc-specific IgG2 subclass in cerebrospinal fluid (CSF) selectively targeted human neuronal cells as well as GlcNAc in the ELISA. In rheumatic carditis, the IgG2 subclass preferentially and strongly deposited in valve tissues (n = 4) despite elevated concentrations of IgG1 and IgG3 in RHD sera as detected by ELISA to group A streptococcal M protein. Although our human study of ARF includes a very small limited sample set, our novel research findings suggest a strong IgG2 autoantibody response against GlcNAc in RHD and SC, which targeted heart valves and neuronal cells. Cardiac IgG2 deposition was identified with an associated IL-17A/IFN-γ cooperative signature in RHD tissue which displayed both IgG2 deposition and cellular infiltrates demonstrating these cytokines simultaneously. GlcNAc-specific IgG2 may be an important autoantibody in initial stages of the pathogenesis of group A streptococcal sequelae, and future studies will determine if it can serve as a biomarker for risk of RHD and SC or early diagnosis of ARF.

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