Rheumatic fever

Substance P receptor antagonism: a potential novel treatment option for viral-myocarditis

Viral-myocarditis is an important cause of heart failure for which no specific treatment is available. We previously showed the neuropeptide substance P (SP) is associated with the pathogenesis of murine myocarditis caused by encephalomyocarditis virus (EMCV). The current studies determined if pharmacological inhibition of SP-signaling via its high affinity receptor, NK1R and downstream G-protein, Ras homolog gene family, member-A (RhoA), will be beneficial in viral-myocarditis. Aprepitant (1.2 mg/kg), a SP-receptor antagonist, or fasudil (10 mg/kg), a RhoA inhibitor, or saline control was administered daily to mice orally for 3 days, prior to, or 5 days following, intraperitoneal infection with and without 50 PFU of EMCV, following which disease assessment studies, including echocardiogram and cardiac Doppler were performed in day 14 after infection. Pretreatment and posttreatment with aprepitant significantly reduced mortality, heart and cardiomyocyte size, and cardiac viral RNA levels (P < 0.05 all, ANOVA). Only aprepitant pretreatment improved heart functions; it significantly decreased end systolic diameter, improved fractional shortening, and increased peak aortic flow velocity (P < 0.05 all, ANOVA). Pre- or posttreatment with fasudil did not significantly impact disease manifestations. These findings indicate that SP contributes to cardiac-remodeling and dysfunction following ECMV infection via its high affinity receptor, but not through the Rho-A pathway. These studies suggest that SP-receptor antagonism may be a novel therapeutic-option for patients with viral-myocarditis.

Cutting edge issues in rheumatic fever

Although the incidence of acute rheumatic fever and rheumatic heart disease has decreased significantly in regions of the world where antibiotics are easily accessible, there remains a high incidence in developing nations as well as in certain regions where there is a high incidence of genetic susceptibility. These diseases are a function of poverty, low socioeconomic status, and barriers to healthcare access, and it is in the developing world that a comprehensive prevention program is most critically needed. Development of group A streptococcal vaccines has been under investigation since the 1960s and 50 years later, we still have no vaccine. Factors that contribute to this lack of success include a potential risk for developing vaccine-induced rheumatic heart disease, as well as difficulties in covering the many serological subtypes of M protein, a virulence factor found on the surface of the bacterium. Yet, development of a successful vaccine program for prevention of group A streptococcal infection still offers the best chance for eradication of rheumatic fever in the twenty-first century. Other useful approaches include continuation of primary and secondary prevention with antibiotics and implementation of health care policies that provide patients with easy access to antibiotics. Improved living conditions and better hygiene are also critical to the prevention of the spread of group A streptococcus, especially in impoverished regions of the world. The purpose of this article is to discuss current and recent developments in the diagnosis, pathogenesis, and management of rheumatic fever and rheumatic heart disease.

Native Cardiac Valve Pathology

Anatomy of the native cardiac valves, reasons for surgical excision and examination, and a summary of the gross examination and documentation are presented. Aortic stenosis, aortic valve regurgitation, tricuspid and pulmonary valve pathology, mitral stenosis, and mitral insufficiency are each presented with an overview, focused anatomy, and discussion of pathologic diagnosis by gross examination and histology.

Inflammatory regulation of valvular remodeling: the good(?), the bad, and the ugly

Heart valve disease is unique in that it affects both the very young and very old, and does not discriminate by financial affluence, social stratus, or global location. Research over the past decade has transformed our understanding of heart valve cell biology, yet still more remains unclear regarding how these cells respond and adapt to their local microenvironment. Recent studies have identified inflammatory signaling at nearly every point in the life cycle of heart valves, yet its role at each stage is unclear. While the vast majority of evidence points to inflammation as mediating pathological valve remodeling and eventual destruction, some studies suggest inflammation may provide key signals guiding transient adaptive remodeling. Though the mechanisms are far from clear, inflammatory signaling may be a previously unrecognized ally in the quest for controlled rapid tissue remodeling, a key requirement for regenerative medicine approaches for heart valve disease. This paper summarizes the current state of knowledge regarding inflammatory mediation of heart valve remodeling and suggests key questions moving forward.

Henoch-Schönlein purpura complicated by cardiac involvement: case report and review of the literature

Involvement of the kidneys in Henoch-Schönlein purpura (HSP) occurs in approximately 50% of patients with HSP, with varying severity. In general, disease outcome is favorable for adolescents. However, severe courses with vasculitis impairing multiple organ systems in addition to the kidney, including brain, heart, and intestine, may occur. This involvement, often manifesting more subtly, requires alertness for diagnosis and escalation of immunosuppressive therapy for treatment. We report a case of severe HSP nephritis with cardiac involvement in a young man. Cardiac involvement was noted initially on an electrocardiogram and visualized by using cardiac magnetic resonance imaging. HSP remission was induced with aggressive cytotoxic therapy, consisting of cyclophosphamide (750 mg/m(2) every 4 weeks) in addition to high-dose prednisolone. The case presentation is followed by a review of the literature for manifestations, treatments, and outcomes in patients with HSP complicated by cardiac involvement.

Inflammatory cardiac valvulitis in TAX1BP1-deficient mice through selective NF-kappaB activation

Nuclear factor kappa B (NF-kappaB) is a key mediator of inflammation. Unchecked NF-kappaB signalling can engender autoimmune pathologies and cancers. Here, we show that Tax1-binding protein 1 (TAX1BP1) is a negative regulator of TNF-alpha- and IL-1beta-induced NF-kappaB activation and that binding to mono- and polyubiquitin by a ubiquitin-binding Zn finger domain in TAX1BP1 is needed for TRAF6 association and NF-kappaB inhibition. Mice genetically knocked out for TAX1BP1 are born normal, but develop age-dependent inflammatory cardiac valvulitis, die prematurely, and are hypersensitive to low doses of TNF-alpha and IL-1beta. TAX1BP1-/- cells are more highly activated for NF-kappaB than control cells when stimulated with TNF-alpha or IL-1beta. Mechanistically, TAX1BP1 acts in NF-kappaB signalling as an essential adaptor between A20 and its targets.

Pathology of inflammatory native valvular heart disease

Rheumatic disease is an important cause of inflammatory native heart valve disease. However, with increased understanding of the pathoetiology of valve disease and valve injury, it is evident that inflammation may play a role in many valve disorders. We are only beginning to understand these complex processes. With increasing knowledge that many of these processes are active, there may be opportunity for intervention or even prevention.

Hypoplastic left heart syndrome: Rheumatic heart disease of the fetus?

Hypoplastic left heart syndrome (HLHS) accounts for nearly 25% of deaths among neonates with congenital heart disease. The essential feature of HLHS is a small left ventricle (LV) incapable of supporting the circulation. The etiology of HLHS is unknown. A hypothesis is proposed implicating an immune mechanism involving maternal antibodies produced in response to pharyngitis caused by group A beta-hemolytic streptococci (GABHS) ("strep throat"). After crossing the placenta, the antibodies injure the developing fetal heart, leading to HLHS either because of direct injury to the LV or secondary to reduced blood flow through affected aortic and mitral valves. Analogy is drawn to rheumatic heart disease (RHD), a known sequela of strep throat. In RHD a misdirected immune response originally intended for GABHS leads to cardiac injury through "molecular mimicry"; the normal heart antigens supposedly mimic the GABHS antigens. A similar pathogenesis is proposed for HLHS and related heart defects. HLHS may represent an extreme form of injury, while a milder insult may present as only mild aortic stenosis or a bicuspid aortic valve, conditions with wide prevalence among the general population. The injury may indeed superimpose on many other congenital heart defects, leading to a variable presentation of these other diseases. Beside remarkable likenesses between HLHS and RHD, the hypothesis is also supported by increasing evidence for the role of deleterious transplacental antibodies in the pathogenesis of other fetal diseases. Implications for other congenital heart diseases and the broader picture of global public health are discussed.

Henoch-Schönlein purpura: a case with atypical presentation

We report on a case of Henoch-Schönlein purpura (HSP) with pulmonary hemorrhage and severe renal involvement. The patient also had active carditis related to acute rheumatic fever. He died despite intensive treatment. Regarding this case, we discuss the pathogenesis and clinical findings of pulmonary hemorrhage and active carditis in HSP.

Antibiotics for the primary prevention of acute rheumatic fever: a meta-analysis

BACKGROUND

Rheumatic fever continues to put a significant burden on the health of low socio-economic populations in low and middle-income countries despite the near disappearance of the disease in the developed world over the past century. Antibiotics have long been thought of as an effective method for preventing the onset of acute rheumatic fever following a Group-A streptococcal (GAS) throat infection; however, their use has not been widely adopted in developing countries for the treatment of sore throats. We have used the tools of systematic review and meta-analysis to quantify the effectiveness of antibiotic treatment for sore throat, with symptoms suggestive of group A streptococcal (GAS) infection, for the primary prevention of acute rheumatic fever.

METHODS

Trials were identified through a systematic search of titles and abstracts found in the Cochrane Central Register of Controlled Trials (Cochrane Library Issue 4, 2003), MEDLINE (1966-2003), EMBASE (1966-2003), and the reference lists of identified studies. The selection criteria included randomised or quasi-randomised controlled trials comparing the effectiveness of antibiotics versus no antibiotics for the prevention of rheumatic fever in patients presenting with a sore throat, with or without confirmation of GAS infection, and no history of rheumatic fever.

RESULTS

Ten trials (n = 7665) were eligible for inclusion in this review. The methodological quality of the studies, in general, was poor. All of the included trials were conducted during the period of 1950 and 1961 and in 8 of the 10 trials the study population consisted of young adult males living on United States military bases. Fixed effects, meta-analysis revealed an overall protective effect for the use of antibiotics against acute rheumatic fever of 70% (RR = 0.32; 95% CI = 0.21-0.48). The absolute risk reduction was 1.67% with an NNT of 53. When meta-analysis was restricted to include only trials evaluating penicillin, a protective effect of 80% was found (Fixed effect RR = 0.20, 95% CI = 0.11-0.36) with an NNT of 60. The marginal cost of preventing one case of rheumatic fever by a single intramuscular injection of penicillin is approximately USD 46 in South Africa.

CONCLUSION

Antibiotics appear to be effective in reducing the incidence of acute rheumatic fever following an episode of suspected GAS pharyngitis. This effect may be achieved at relatively low cost if a single intramuscular penicillin injection is administered.

Rheumatic fever and rheumatic heart disease: clinical profile of 550 cases in India

BACKGROUND

The aims and objectives of this paper were to analyze the clinical presentation of children with rheumatic fever (RF) and rheumatic heart disease (RHD), to determine the cardiac sequel of RF and valvular affection due to RF, and to study clinical manifestations in recurrences of RF.

METHODS

Our study, a retrospective analysis, was conducted at a tertiary-care teaching hospital with specialty follow-up clinic for patients with RF/RHD. This retrospective study was conducted to include a period of 31 years (from January 1971 through December 2001). Pre-completed case protocols of patients with RF/RHD were analyzed to record the following information: demographic data; clinical features on admission/presentation; relevant investigations; recurrences; cardiac valvular affection, and outcome. Modified Jones' criteria were used for diagnosis of RF.

RESULTS

The study included 550 patients. Mean age of presentation was 9.62 years and sex ratio was 1.15:1 favoring males. A total of 250 patients presented with initial/first attack of RF. Arthritis and carditis were seen in 169 (67.6%) and 105 cases (42%), respectively. Chorea was seen in 47 cases (18.8%) and erythema marginatum, in four. A total of 224 patients presented with recurrence of RF (with pre-existing RHD). Arthritis and carditis were seen in 109 (48.66%) and 178 cases (79.46%), respectively, in these patients; 76 cases presented with chronic RHD. Mitral regurgitation was the most common cardiac valvular lesion observed (150 cases) followed by a combination of mitral stenosis and mitral regurgitation (98 cases). Congestive cardiac failure was seen in 201 cases (36.54%) and infective endocarditis in 30 (5.45%). 2-D echocardiography and/or color Doppler was performed in 201 patients (36.54%). Average duration of follow-up was 3.19 years; 74.72% of cases were lost to follow-up. Benzathine penicillin prophylaxis was regular in 42.18% cases. Positive family history of RF/RHD was present in 2% of cases. Twenty three patients (4.18%) died.

CONCLUSIONS

Arthritis was the most common manifestation in the initial attack of RF, while carditis was the most common manifestation in patients presenting with rheumatic recurrences (with pre-existing RHD) and mitral regurgitation was the most common valvular lesion. Rate of patient dropout from penicillin prophylaxis was high. Clinical manifestations in initial/first attack of RF have not significantly changed in the last 31 years.

Self epitopes shared between human skeletal myosin and Streptococcus pyogenes M5 protein are targets of immune responses in active juvenile dermatomyositis

OBJECTIVE

To identify self T cell epitopes associated with proinflammatory immune responses and clinically active juvenile dermatomyositis (juvenile DM). The target of our search for relevant epitopes was represented by amino acid sequences shared between human skeletal myosin and Streptococcus pyogenes M5 protein. The long-term objective of the project is to identify suitable targets for immunotherapy of the disease.

METHODS

We used computerized algorithms to identify putative agretopes on both the human myosin and Streptococcus M5 proteins. Direct binding assays for homolog peptides were used to confirm such predictions. Antigenicity and functional cross-reactivity were evaluated by cytotoxicity assays and by measurement of cytokine levels. Specific T cells were isolated by T cell capture, and T cell receptor (TCR) V(beta) gene usage was identified by reverse transcriptase-polymerase chain reaction.

RESULTS

We identified peptides that are targets of disease-specific cytotoxic T cell responses. T cell reactivity against the self peptides correlates with clinical signs of early, active myositis. Such reactivity is accompanied by production of proinflammatory cytokines, which may contribute to the damage. T cell cross-recognition of bacterial and human homologs was shown functionally as well as by sorting peptide-specific T cells and identifying oligoclonal and largely overlapping TCR V(beta) gene usage.

CONCLUSION

These findings represent the first identification of a self epitope in juvenile DM, providing a potential candidate for antigen-specific immune therapy.