Targeting matrix metalloproteinase activity and expression for the treatment of viral myocarditis

Infectious agents including viruses can infect the heart muscle, resulting in the development of heart inflammation called myocarditis. Chronic myocarditis can lead to dilated cardiomyopathy (DCM). DCM develops from the extensive extracellular matrix (ECM) remodeling caused by myocarditis and may result in heart failure. Epidemiological data for viral myocarditis has long suggested a worse pathology in males, with more recent data demonstrating sex-dependent pathogenesis in DCM as well. Matrix metalloproteinases (MMPs), long known modulators of the extracellular matrix, have important roles in mediating heart inflammation and remodeling during disease and in convalescence. This ability of MMPs to control both the inflammatory response and ECM remodeling during myocarditis makes them potential drug targets. In this review, we analyze the role of MMPs in mediating myocarditis/DCM disease progression, their sex-dependent expression, and their potential as drug targets during viral myocarditis and DCM.

A fatal case of acute myocardial infarction following the improvement of influenza A(H1N1)pdm2009-related acute myocarditis

A 52-year-old Indian man was hospitalized due to dyspnea and a high fever caused by influenza A(H1N1)pdm2009. Elevated cardiac enzymes, a chest X-ray showing bilateral infiltrative shadows, cardiomegaly and pleural effusion and echocardiography indicating diffuse hypokinesis of the left ventricle suggested cardiac failure due to acute myocarditis. Owing to the administration of combined modality therapy, including steroids and intravenous γ-globulin, the patient's clinical symptoms of influenza completely resolved. However, he suddenly complained of epigastric pain due to acute myocardial infarction and died. This report is an educational case, the results of which suggest that greater attention should be paid to the potential for myocardial infarction even after an influenza virus infection is found to improve.

Inhibition of Coxsackievirus-associated dystrophin cleavage prevents cardiomyopathy

Heart failure in children and adults is often the consequence of myocarditis associated with Coxsackievirus (CV) infection. Upon CV infection, enteroviral protease 2A cleaves a small number of host proteins including dystrophin, which links actin filaments to the plasma membrane of muscle fiber cells (sarcolemma). It is unknown whether protease 2A-mediated cleavage of dystrophin and subsequent disruption of the sarcolemma play a role in CV-mediated myocarditis. We generated knockin mice harboring a mutation at the protease 2A cleavage site of the dystrophin gene, which prevents dystrophin cleavage following CV infection. Compared with wild-type mice, we found that mice expressing cleavage-resistant dystrophin had a decrease in sarcolemmal disruption and cardiac virus titer following CV infection. In addition, cleavage-resistant dystrophin inhibited the cardiomyopathy induced by cardiomyocyte-restricted expression of the CV protease 2A transgene. These findings indicate that protease 2A-mediated cleavage of dystrophin is critical for viral propagation, enteroviral-mediated cytopathic effects, and the development of cardiomyopathy.

Corticosteroids for viral myocarditis

BACKGROUND

Myocarditis is defined as inflammation of the myocardium accompanied by myocellular necrosis. Experimental evidence suggests that autoimmune mechanisms follow viral infection, resulting in inflammation and necrosis in the myocardium. However, the use of corticosteroids as immunosuppressives for this condition remains controversial.

OBJECTIVES

The existing review was updated. The primary objective of this review is to assess the beneficial and harmful effects of treating acute or chronic viral myocarditis with corticosteroids. The secondary objective is to determine the best dose regimen.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 7 of 12, 2012) on The Cochrane Library, MEDLINE OVID (1946 to July Week 2, 2012), EMBASE OVID (1980 to Week 29, 2012), BIOSIS Previews (1969 to 20 July 2012), ISI Web of Science (1970 to 20th July, 2012), and LILACS (from its inception to 25 July, 2012) , Chinese Biomed Database, CNKI and WANFANG Databases (from their inception to 31 December 2012). We applied no language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of corticosteroids for viral myocarditis compared with no intervention, placebo, supportive therapy, antiviral agents therapy or conventional therapy, including trials of corticosteroids plus other treatment versus other treatment alone, irrespective of blinding, publication status, or language.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently. Results were presented as risk ratios (RRs) and mean differences (MDs), both with 95% confidence intervals (CIs).

MAIN RESULTS

Eight RCTs (with 719 participants) were included in this update. The trials were small in size and methodological quality was poor. Viral detection was performed in 38% of participants, among whom 56% had positive results. Mortality between corticosteroids and control groups was non-significant (RR, 0.93, 95% CI 0.70 to 1.24). At 1 to 3 months follow-up, left ventricular ejection fraction (LVEF) was higher in the corticosteroids group compared to the control group (MD 7.36%, 95% CI 4.94 to 9.79), but there was substantial heterogeneity. Benefits were observed in LVEF in two trials with 200 children given corticosteroids (MD 9.00%, 95% CI 7.48 to 10.52). New York Heart Association (NYHA) class and left ventricular end-stage systole diameter (LVESD) were not affected. Creatine phosphokinase (CPK) (MD -104.00 U/L, 95% CI -115.18 to -92.82), Isoenzyme of creatine phosphate MB (CKMB) (MD 10.35 U/L, 95% CI 8.92 to 11.78), were reduced in the corticosteroids group compared to the control group, although the evidence is limited to small participant numbers. There were insufficient data on adverse events.

AUTHORS' CONCLUSIONS

For people diagnosed with viral myocarditis and low LVEF, corticosteroids do not reduce mortality. They may improve cardiac function but the trials were of low quality and small size so this finding must be regarded as uncertain. High-quality, large-scale RCTs should be careful designed to determine the role of corticosteroid treatment for viral myocarditis. Adverse events should also be carefully evaluated.

Acute right ventricular myocarditis presenting with chest pain and syncope

Myocarditis is assumed to involve both ventricles equally. Right ventricular predominant involvement is rarely described. A case of acute viral right ventricular myocarditis presenting with chest pain and syncope, grade 3 atrioventricular block, right ventricular dilatation and free wall hypokinesia is reported. Cardiac MRI showed late enhancement of the right ventricular free wall without involvement of the left ventricle. Anti-Coxsackie A9 virus neutralising IgM-type antibodies titre was elevated. This case emphasises that manifestations of myocarditis can be limited to the right ventricle and should be considered in the differential diagnosis of right ventricular enlargement.

In vitro and in vivo studies of the inhibitory effects of emodin isolated from Polygonum cuspidatum on Coxsakievirus B₄

The lack of effective therapeutics for Coxsackievirus B₄ (CVB₄) infection underscores the importance of finding novel antiviral compounds. Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is one of the natural anthraquinone derivatives obtained from the root and rhizome of Polygonum cuspidatum. In the present study, the possibility of using emodin as a potential antiviral to treat CVB₄ infection was explored in vitro and in mice. Emodin reduced CVB₄ entry and replication on Hep-2 cells in a concentration- and time-dependent manner, with a 50% effective concentration (EC₅₀) of 12.06 μM and selectivity index (SI) of 5.08, respectively. The inhibitory effect of emodin for CVB₄ entry and replication was further confirmed by a quantitative real time PCR (qPCR) assay. The results further showed that the mice orally treated with different dosages of emodin displayed a dose dependent increase of survival rate, body weight and prolonged mean time of death (MTD), accompanied by significantly decreased myocardial virus titers and pathologic scores/lesions. Moreover, emodin could inhibit CVB₄-induced apoptosis in vitro and in vivo. Our results indicated that emodin could be used as potential antiviral in the post-exposure prophylaxis for CVB₄ infection.

Herbal medicines for viral myocarditis

BACKGROUND

Herbal medicines are used as treatment for viral diseases such as viral myocarditis, and numerous clinical trials have been conducted to investigate their efficacy. Despite this wealth of evidence, the role of herbal medicines in the treatment of viral myocarditis has yet to be established. This is an update of a review published in 2012.

OBJECTIVES

To assess the benefits and harms of herbal medicines on clinical (e.g. mortality, incidence of complications) and indirect outcomes (e.g. cardiac function, biochemical response) in patients with viral myocarditis, irrespective of the patients' age, gender or type (including acute and chronic viral myocarditis).

SEARCH METHODS

We searched CENTRAL (2013, Issue 1) on The Cochrane Library, MEDLINE (Ovid, 1946 to January Week 4 2013), EMBASE (Ovid, 1980 to 2013 Week 04) and LILACS (Bireme) on 1 February 2013. We previously searched The Chinese Biomedical Database (1979 to 2011), China National Knowledge Infrastructure (1979 to 2011), Chinese VIP Information (1989 to 2011), Chinese Academic Conference Papers Database and Chinese Dissertation Database (1980 to 2011), AMED (June 2011) and the Cochrane Complementary Medicine Field Trials Register (June 2011). We handsearched Chinese journals and conference proceedings. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials of herbal medicines (with a minimum duration of seven days of treatment) compared with placebo, no intervention, or conventional interventions were included. Trials of herbal medicine plus a conventional drug versus the drug alone were also included. We included only trials that reported an adequate description of allocation sequence generation.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and evaluated trial quality. Information on adverse effects was collected from the trial reports.

MAIN RESULTS

We did not identify any new trials with the updated search in February 2013. The 2011 update of this review included twenty randomised controlled trials involving 2177 people. All the trials were conducted and published in China. The controls included anti-arrhythmic drugs, corticosteroids, and antiviral therapies such as ribavirin or interferon. Combining the risk of bias for random sequence generation, allocation concealment, selective reporting, and incomplete outcome data, we assessed the included trials as being at a high risk of bias. Thirteen different herbal medicines were tested in the included trials. One of the trials reported outcomes on mortality. The trials reported electrocardiogram results, levels of myocardial enzymes, cardiac function, and adverse effects.Compared with supportive therapy, Astragalus membranaceus injection did not show a significant reduction in the number of patients that died of cardiac failure.A meta-analysis showed a significant effect ofAstragalus membranaceus injection plus supportive therapy on the number of participants with an abnormal electrocardiogram (RR 0.28, 95% CI 0.13 to 0.61), ST-T changes (RR 0.72, 95% CI 0.54 to 0.95), creatine phosphate kinase (CPK) levels (MD -21.54, 95% CI -33.80 to -9.28), and lactate dehydrogenase (LDH) levels (MD -30.33, 95% CI -46.78 to -13.88).Shengmai injection plus supportive therapy showed a significant effect on the number of patients with an abnormal electrocardiogram (RR 0.11, 95% CI 0.01 to 0.86), CPK levels (MD -103.90, 95% CI -114.97 to -92.83), LDH levels (MD -34.60, 95% CI -51.25 to -17.95), and on myocardial enzyme CK-MB levels (MD -10.87, 95% CI -14.50 to -7.24). Shengmai decoction plus supportive therapy showed a significant effect on improving quality of life measured by the SF-36 (MD 40.20, 95% CI 18.13 to 62.27) compared to supportive therapy. Data on adverse events were only available from six of the included trials and no serious adverse effects were reported.

AUTHORS' CONCLUSIONS

Since no new trials were identified in the updated search in 2013, the conclusions remain the same as they were in 2012. There is no evidence of benefit of herbal medicine on all cause mortality. Some herbal medicines may lead to improvement of ventricular premature beat, electrocardiogram, levels of myocardial enzymes, and cardiac function in viral myocarditis. However, these findings should be interpreted with care, due to the risk of bias of the included studies, small sample size, and limited number of trials on individual herbs. Further robust trials are needed to explore the use of herbal medicines for viral myocarditis.

In vivo delivery of adenoviral vector containing interleukin-17 receptor a reduces cardiac remodeling and improves myocardial function in viral myocarditis leading to dilated cardiomyopathy

Th17 cells have been implicated in the pathogenesis of myocarditis. Interleukin (IL)-17A produced by Th17 cells is dispensable for viral myocarditis but essential for the progression to dilated cardiomyopathy (DCM). This study investigated whether the adenoviral transfer of the IL-17 receptor A reduces myocardial remodeling and dysfunction in viral myocarditis leading to DCM. In a mouse model of Coxsackievirus B3 (CVB3)-induced chronic myocarditis, the delivery of the adenovirus-containing IL-17 receptor A (Ad-IL17RA:Fc) reduced IL-17A production and decreased the number of Th17 cells in the spleen and heart, leading to the down-regulation of systemic TNF-α and IL-6 production. Cardiac function improved significantly in the Ad-IL17R:Fc- compared with the Ad-null-treated mice 3 months after the first CVB3 infection. Ad-IL17R:Fc reduced the left ventricle dilation and decreased the mortality in viral myocarditis, leading to DCM (56% in the Ad-IL17R:Fc versus 76% in the Ad-null group). The protective effects of Ad-IL17R-Fc on remodeling correlated with the attenuation of myocardial collagen deposition and the reduction of fibroblasts in CVB3-infected hearts, which was accompanied by the down-regulation of A distintegrin and metalloprotease with thrombospondin type 1 motifs (ADAMTS-1), Matrix metalloproteinase-2(MMP-2), and collagen subtypes I and III in the heart. Moreover, in cultured cardiac fibroblasts, IL-17A induced the expression of ADAMTS-1, MMP-2, and collagen subtypes I and III and increased the proliferation of fibroblasts. We determined that the delivery of IL-17-RA:Fc reduces cardiac remodeling, improves function, and decreases mortality in viral myocarditis leading to DCM, possibly by suppressing fibrosis. Therefore, the adenoviral transfer of the IL-17 receptor A may represent an alternative therapy for chronic viral myocarditis and its progression to DCM.

Protective effects of losartan in mice with chronic viral myocarditis induced by coxsackievirus B3

AIM

To investigate whether losartan has protective effects in mice with chronic viral myocarditis induced by coxsackievirus B3 (CVB3).

MAIN METHODS

Thirty two male Balb/c mice were intraperitoneally injected with CVB3 (10×TCID50) to induce chronic viral myocarditis (CVM). Losartan at 12.5mg/kg (n=16) or normal saline (n=16) were orally administered daily for 28 days to these mice. Uninfected mice (n=6) were used as controls. On day 29, all mice underwent anesthesia and echocardiography prior to sacrifice. Serum IL-17, IL-4, IFN-γ and TNF-α levels were measured by enzyme-linked immunosorbent assay, and cardiac tissues were histologically examined after hematoxylin & eosin staining. In addition, the effect of losartan on the virus titers in primary cultured neonatal rat cardiomyocytes infected with CVB3 was measured on Hep-2 cells at 72 h post infection.

KEY FINDINGS

Mice infected with CBV3 had significantly increased mortality, heart/body weight ratios, necrosis and inflammatory scores and decreased cardiac ejection fractions, compared with the controls (all P<0.05). Losartan significantly decreased mortality from 40.0% to 12.5%, heart/body weight ratios from 7.08 ± 2.17 to 4.15 ± 0.99, and necrosis and inflammatory scores from 3.33 ± 0.50 to 2.50 ± 0.65 (all P<0.05), and increased ejection fractions from 55.80 ± 9.25 to 72.31 ± 12.15 (P<0.05). Losartan significantly enhanced IL-4, and decreased IFN-γ, TNF-α and IL-17 (all P<0.05). In the in vitro experiment, losartan had no influence on virus titers.

SIGNIFICANCE

Losartan protects mice against CVB3-induced CVM, most likely through upregulating Th2 responses, and down-regulating Th1 and Th17 responses.

[Myocardial expression of Spry1 and MAPK proteins of viral myocarditis]

OBJECTIVE

To discuss the myocardial expression of Spry1 and MAPK proteins of viral myocarditis (VMC), to reveal its mechanism of sudden death, and to provide guides for forensic identification of sudden cardiac death.

METHODS

Thirty Balb/c male mice were randomly divided into VMC group and control group, inoculated intraperitoneally with Coxsackievirus B3 and Eagel's solution, respectively. After the mice were sacrificed, the cardiac tissues of the mice were taken to proceed regular pathological examination. The changes of Spry1 protein, Spry1 mRNA and MAPK protein were detected by immunohistochemistry, Western blotting and real-time PCR.

RESULTS

Under light microscope, the pathologic changes included myocardial interstitial edema, inflammatory cells infiltration, myocardial necrosis, and focal and patchy necrosis of myocardial fiber in VMC group. The expression of Spry1 protein in VMC group was lower than that in control group (P < 0.05). There was slightly decreased expression of Spry1 of the mRNA level in VMC group (P > 0.05). But the MAPK protein expression in VMC group was higher than that in control group (P < 0.05).

CONCLUSION

The pathway of MAPK/ERK involving Spry1 protein accelerates the expression of collagen, which may contribute to arrhythmia, heart failure and even sudden cardiac death.

IL-22 exacerbates the severity of CVB3-induced acute viral myocarditis in IL-17A-deficient mice

Interleukin (IL)-22 has either proinflammatory or tissue‑protective properties, depending on the nature of the affected tissue and the local cytokine milieu, including the presence or absence of IL-17A co-expression. We have previously demonstrated that IL-22 has critical anti-inflammatory and antiviral roles in mice with coxsackievirus B3 (CVB3)‑induced acute viral myocarditis (AVMC) in the presence of IL-17A. However, whether IL-17A determines the function of IL-22 in AVMC remains unknown. Therefore, the present study, in continuation of our previous investigations, aimed to determine whether IL-22 plays a distinctly different role in the absence of IL-17A in AVMC by using IL-17A-deficient mice. Results demonstrated that the neutralization of IL-22 in IL-17A‑deficient mice alleviated the severity of myocarditis. This was demonstrated by the lower pathological scores of heart sections and ratios of heart weight/body weight (HW/BW), reduced production of activator of transcription 3 (STAT3) and proinflammatory cytokines TNF-α and IL-6, followed by increased viral replication and decreased levels of the antiviral cytokine IFN-γ. Furthermore, the correlation between cardiac CVB3 RNA and IL-22 mRNA or IFN-γ mRNA was negative. In conclusion, IL-22 exacerbated the severity of AVMC and restrained viral replication in the absence of IL-17A. Spleen lymphocytes cultured with recombinant IL-17 (rIL-17) increased the production of IL-22. Combined with our previous data, these results indicate that IL-17A is not involved in regulating the antiviral role, however, may mediate the tissue-protective versus pathogenic properties of IL-22 in CVB3-induced AVMC in mice.

Acute viral myocarditis: current concepts in diagnosis and treatment

Acute myocarditis is one of the most challenging diseases to diagnose and treat in cardiology. The true incidence of the disease is unknown. Viral infection is the most common etiology. Modern techniques have improved the ability to diagnose specific viral pathogens in the myocardium. Currently, parvovirus B19 and adenoviruses are most frequently identified in endomyocardial biopsies. Most patients will recover without sequelae, but a subset of patients will progress to chronic inflammatory and dilated cardiomyopathy. The pathogenesis includes direct viral myocardial damage as well as autoimmune reaction against cardiac epitopes. The clinical manifestations of acute myocarditis vary widely--from asymptomatic changes on electrocardiogram to fulminant heart failure, arrhythmias and sudden cardiac death. Magnetic resonance imaging is emerging as an important tool for the diagnosis and follow-up of patients, and for guidance of endomyocardial biopsy. In the setting of acute myocarditis endomyocardial biopsy is required for the evaluation of patients with a clinical scenario suggestive of giant cell myocarditis and of those who deteriorate despite supportive treatment. Treatment of acute myocarditis is still mainly supportive, except for giant cell myocarditis where immunotherapy has been shown to improve survival. Immunotherapy and specific antiviral treatment have yet to demonstrate definitive clinical efficacy in ongoing clinical trials. This review will focus on the clinical manifestations, the diagnostic approach to the patient with clinically suspected acute myocarditis, and an evidence-based treatment strategy for the acute and chronic form of the disease.

Shenqi fuzheng injection improves cvb3-induced myocarditis via inhibiting traf6 expression

Viral myocarditis is a main cause of heart failure in young adults, which characterized by cardiac inflammation and caused by Coxsackievirus B3 (CVB3) infection. However, efficient therapies targeting inflammation and inflammatory response pathway are still elusive. Shenqi Fuzheng injection (SQFZI) is extensively applied in the cardiovascular diseases. But whether SQFZI may affect cardiac inflammation during acute viral myocarditis remains to be elucidated. The purpose of the present study was to investigate the potential protective effect of SQFZI on CVB3-induced myocarditis. Total of 120 mice were intraperitoneally inoculated with CVB3 to establish acute viral myocarditis model. For the CVB3-infected mice model, the body weight, mortality was observed. RT-PCR, western blot and immunohistochemistry methods were selected to detect the TRAF6 expression in myocardial tissues. We found that the expression of TRAF6 mRNA and protein were markedly and persistently increased during the progression of CVB3-induced myocarditis. The serum enzymes activity, including CK, CK-MB, LDH, AST, were also enhanced in CVB3-induced myocardial tissues. Notably, injection with SQFZI remarkably reduced CVB3-induced TRAF6 production and alleviated the severity of myocarditis. This study demonstrates the protective role of SQFZI against CVB3-induced myocarditis, which may explore a new therapeutic strategy for the treatment of viral myocarditis.

Genetic variation in Norwegian piscine myocarditis virus in Atlantic salmon, Salmo salar L

Cardiomyopathy syndrome (CMS) in Atlantic salmon, Salmo salar L., is a severe cardiac disease characterized by a necrotizing myocarditis involving the atrium and the spongious part of the ventricle. The disease is caused by piscine myocarditis virus (PMCV), a double-stranded RNA virus likely belonging to the family Totiviridae. The objective of this study was to evaluate the genetic variation in Norwegian PMCV isolates focusing on the putative structural proteins encoded by open reading frames (ORFs) 1 and 3. The virus isolates were sampled from a total of 36 farms along the Norwegian coastline. This study represents the first investigation of PMCV genome variation and shows that Norwegian isolates are highly similar, with the most divergent isolates sharing 98.6% nucleotide identity. Interestingly, amino acid sequence diversity within ORF3 is approximately threefold higher than for ORF1. While phylogenetic analysis based on concatenated nucleotide data covering ORF1 and ORF3 revealed four main clusters, the maximum sequence variation of 1.4% at the nucleotide level suggests that all Norwegian isolates belong to a single genogroup. Substantial sequence variation within farms was also observed, which may complicate future molecular epidemiological investigations. The genetic homogeneity among the Norwegian isolates might facilitate development of both diagnostic tools and an efficient vaccine against CMS in the future.

Dengue myocarditis in Singapore: two case reports

The authors report two cases of complicated dengue viral infection with acute myocarditis involving young male adults, of which one was fatal. The first case presented with typical signs of myocardial disease: chest pain and diaphoresis with myocardial depression in the electrocardiograph. The second case deteriorated rapidly and demised within the first day of admission. Histology of the heart muscles showed multiple small foci of myocyte necrosis surrounded by lymphocytes, in keeping with viral myocarditis. Both cases fulfilled the World Health Organization (WHO) diagnosis of probable dengue: the first case had positive dengue serology, both IgM and IgG at day six of illness, and the second case was polymerase chain reaction (PCR) positive for dengue and identified as serotype 2. Despite the severe outcome, both cases did not completely fulfil the criteria for dengue haemorrhagic fever (DHF). Although severe cardiac impairment is not commonly reported in dengue infection, it can be life threatening.

Clinical spectrum of dengue fever in a tertiary care centre with particular reference to atypical presentation in the 2012 outbreak in Kolkata

During the summer of 2012, dengue fever epidemic has emerged in Kolkata and spread throughout West Bengal. During the epidemic period, wide spectrum of atypical presentations of dengue fever has been observed. Here, in this study, the spectrum of dengue fever was analysed in 300 patients who were found to have dengue serology positive (NS1, IgM, IgG). The study was done in the department of medicine, RG Kar Medical College, Kolkata. The patients were classified according to age, gender, duration of symptoms on admission, associated comorbidities and coinfections, complications that developed after admission, the final outcome and duration till death after symptoms developed. The dengue fever cases started to appear from April but it attained its peak during August-September this year. All ages were affected but the brunt was borne maximally by those between 15 and 40 years. Females were more affected than males. It may be concluded from the study that 30% had no complications while 70% cases developed complications, 4% cases had underlying comorbidities and coinfections, 68% developed thrombocytopenia and other haemorrhagic features, 55% serositis, 25% acalculous cholecystitis, 20% myocarditis, 15% pancreatitis, 5% had central nervous system involvement, 0.66% rhabdomyolysis and myositis, 0.33% secondary vasculitis and death occurred in 3% cases. More number of patients were having multiple and atypical complications requiring hospitalisation. Mortality was more common in patients with associated comorbidities and coinfection. Awareness, early treatment with aggressive fluid replacement therapy with close monitoring, supportive management andpatient education showed promising results.

Herbal medicines for viral myocarditis

BACKGROUND

Herbal medicines are being used as a treatment for viral diseases such as viral myocarditis and numerous clinical trials have been conducted to investigate their efficacy. Despite this wealth of evidence, the role of herbal medicines in the treatment of viral myocarditis is yet to be established. This is an update of the review published in 2010.

OBJECTIVES

To assess the effects of herbal medicines on clinical (for example mortality, incidence of complications) and indirect outcomes (for example cardiac function, biochemical response) in patients with viral myocarditis.

SEARCH METHODS

We searched CENTRAL (The Cochrane Library 2011, Issue 2), MEDLINE (January 1966 to June 2011), EMBASE (January 1998 to June 2011), Chinese Biomedical Database (1979 to 2011), China National Knowledge Infrastructure (1979 to 2011), Chinese VIP Information (1989 to 2011), Chinese Academic Conference Papers Database and Chinese Dissertation Database (1980 to 2011), AMED (June 2011), LILACS (June 2011), and the Cochrane Complementary Medicine Field Trials Register. We handsearched Chinese journals and conference proceedings. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials of herbal medicines (with a minimum of seven days treatment duration) compared with placebo, no intervention, or conventional interventions were included. Trials of herbal medicine plus conventional drug versus drug alone were also included. Only trials that reported an adequate description of allocation sequence generation were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and evaluated trial quality. Adverse effects information was collected from the trials.

MAIN RESULTS

Twenty randomised controlled trials involving 2177 people were included. All trials were conducted and published in China. The controls included anti-arrhythmic drugs, corticosteroids, and antiviral therapies such as ribavirin or interferon. Combining the risk of bias on random sequence generation, allocation concealment, selective reporting, and incomplete outcome data, the included trials were assessed to be at high risk of bias. Thirteen different herbal medicines were tested in the included trials. None of the trials reported outcomes on mortality. The trials reported electrocardiogram results, level of myocardial enzymes, cardiac function, and adverse effects.A meta-analysis showed a significant effect of Astragalus membranaceus injection plus supportive therapy on the number of patients with an abnormal electrocardiogram (RR 0.28, 95% CI 0.13 to 0.61), ST-T changes (RR 0.72, 95% CI 0.54 to 0.95), creatine phosphate kinase (CPK) levels (MD -21.54, 95% CI -33.80 to -9.28), and lactate dehydrogenase (LDH) levels (MD -30.33, 95% CI -46.78 to -13.88).Shengmai injection plus supportive therapy showed a significant effect on the number of patients with an abnormal electrocardiogram (RR 0.11, 95% CI 0.01 to 0.86), CPK levels (MD -103.90, 95% CI -114.97 to -92.83), LDH levels (MD -34.60, 95% CI -51.25 to -17.95), and on myocardial enzyme CK-MB levels (MD -10.87, 95% CI -14.50 to -7.24). Shengmai decoction plus supportive therapy showed a significant effect on improving quality of life measured by the SF-36 (MD 40.20, 95% CI 18.13 to 62.27) compared to supportive therapy. Data on adverse events were only available from six of the included trials and no serious adverse effects were reported.

AUTHORS' CONCLUSIONS

Some herbal medicines may lead to improvement of ventricular premature beat, electrocardiogram, level of myocardial enzymes, and cardiac function in viral myocarditis. However, these findings should be interpreted with care due to the high risk of bias of the included studies, small sample size, and limited number of trials on individual herbs. Further robust trials are needed to explore the use of herbal medicines in viral myocarditis.

[Inhibition of virus infection in coxsackievirus-induced myocarditis model by RNA interference]

To evaluate the effects of lentivirus-delivered short hairpin RNA (shRNA) on CVB3 infection in an animal model by RNA interference technique, we constructed a recombinant lentivirus expressing shRNA-3753 against the viral genome region 3753-3771, then transduced Lenti-sh3753 into mice infected with CVB3. We evaluated the antiviral ability of lenti-sh3753 by cytopathic effect (CPE), viral plaque assay and histological analysis of mice hearts. The results showed that Lenti-sh3753 exhibited a significant protective effect on cell viability and reduction of viral titers in supernatant of cell culture by specific inhibition on viral replication. Lenti-sh3753 also prolonged the mice survival and limited the viral production in mice hearts. These data proposed that Lenti-sh3753 can effectively inhibit CVB3 infection in a coxsackievirus-induced myocarditis model, suggesting its potential role in prevention and therapy of viral diseases.

The prostacyclin agonist iloprost aggravates fibrosis and enhances viral replication in enteroviral myocarditis by modulation of ERK signaling and increase of iNOS expression

Enteroviruses, such as coxsackieviruses of group B (CVB), are able to induce a chronic inflammation of the myocardium, which may finally lead to the loss of functional tissue, remodeling processes and the development of fibrosis, thus affecting the proper contractile function of the heart. In other fibrotic diseases like scleroderma, the prostacyclin agonist iloprost was found to inhibit the extracellular signal-regulated kinase (ERK, p44/42 MAPK), a mitogen-activated protein kinase, and consecutively, the expression of the profibrotic cytokine connective tissue growth factor (CTGF), thereby preventing the development of fibrosis. As CTGF was found to mediate fibrosis in chronic CVB3 myocarditis as well, we evaluated whether the in vivo application of iloprost is capable to reduce the development of ERK/CTGF-mediated fibrosis in enteroviral myocarditis. Unexpectedly, the application of iloprost resulted in a prolonged myocardial inflammation and an aggravated fibrosis and failed to reduce activation of ERK and expression of CTGF at later stages of the disease. In addition, viral replication was found to be increased in iloprost-treated mice. Notably, the expression of cardiac inducible nitric oxide synthase (iNOS), which is known to aggravate myocardial damage in CVB3-infected mice, was strongly enhanced by iloprost. Using cultivated bone marrow macrophages (BMM), we confirmed these results, proving that iloprost potentiates the expression of iNOS mRNA and protein in CVB3-infected and IFN-gamma stimulated BMM. In conclusion, these results suggest a critical reflection of the clinical use of iloprost, especially in patients possibly suffering from an enteroviral myocarditis.

Update on coxsackievirus B3 myocarditis

PURPOSE OF REVIEW

To present recent findings on the pathogenesis of coxsackievirus B3 (CVB3) myocarditis based on animal models, with a focus on the role of T helper (Th) immune responses in disease progression.

RECENT FINDINGS

Acute CVB3 myocarditis is known to be increased by Th1 immune responses, but recent findings indicate that Th1-type immunity protects against acute myocarditis by reducing viral replication and prevents the progression to chronic myocarditis and dilated cardiomyopathy (DCM) by inhibiting Th2 responses. Th2 responses reduce acute myocarditis by inhibiting Th1 responses via regulatory T cells and anti-inflammatory cytokines, but can be deleterious when they induce acute cardiac remodeling leading to chronic myocarditis/DCM. Th2-skewed immune responses allow resistant strains of mice to progress from myocarditis to DCM. In contrast, Th17 responses are elevated during acute and chronic myocarditis and have been found to contribute to cardiac remodeling and DCM.

SUMMARY

Recent data indicate that elevated Th2 and Th17 responses during acute CVB3 myocarditis are critical for the progression from myocarditis to DCM and heart failure because of their ability to induce cardiac remodeling. Th1 responses protect against CVB3 myocarditis by inhibiting Th2 responses and viral replication, but increase acute inflammation.

Comparison of effects of ivabradine versus carvedilol in murine model with the Coxsackievirus B3-induced viral myocarditis

BACKGROUND

Elevated heart rate is associated with increased cardiovascular morbidity. The selective I(f) current inhibitor ivabradine reduces heart rate without affecting cardiac contractility, and has been shown to be cardioprotective in the failing heart. Ivabradine also exerts some of its beneficial effects by decreasing cardiac proinflammatory cytokines and inhibiting peroxidants and collagen accumulation in atherosclerosis or congestive heart failure. However, the effects of ivabradine in the setting of acute viral myocarditis and on the cytokines, oxidative stress and cardiomyocyte apoptosis have not been investigated.

METHODOLOGY/PRINCIPAL FINDINGS

The study was designed to compare the effects of ivabradine and carvedilol in acute viral myocarditis. In a coxsackievirus B3 murine myocarditis model (Balb/c), effects of ivabradine and carvedilol (a nonselective β-adrenoceptor antagonist) on myocardial histopathological changes, cardiac function, plasma noradrenaline, cytokine levels, cardiomyocyte apoptosis, malondialdehyde and superoxide dismutase contents were studied. Both ivabradine and carvedilol similarly and significantly reduced heart rate, attenuated myocardial lesions and improved the impairment of left ventricular function. In addition, ivabradine treatment as well as carvedilol treatment showed significant effects on altered myocardial cytokines with a decrease in the amount of plasma noradrenaline. The increased myocardial MCP-1, IL-6, and TNF-α. in the infected mice was significantly attenuated in the ivabradine treatment group. Only carvedilol had significant anti-oxidative and anti-apoptoic effects in coxsackievirus B3-infected mice.

CONCLUSIONS/SIGNIFICANCE

These results show that the protective effects of heart rate reduction with ivabradine and carvedilol observed in the acute phase of coxsackievirus B3 murine myocarditis may be due not only to the heart rate reduction itself but also to the downregulation of inflammatory cytokines.

Atlantic salmon reovirus infection causes a CD8 T cell myocarditis in Atlantic salmon (Salmo salar L.)

Heart and skeletal inflammation (HSMI) of farmed Atlantic salmon (Salmo salar L.) is a disease characterized by a chronic myocarditis involving the epicardium and the compact and spongious part of the heart ventricle. Chronic myositis of the red skeletal muscle is also a typical finding of HSMI. Piscine reovirus (PRV) has been detected by real-time PCR from farmed and wild salmon with and without typical changes of HSMI and thus the causal relationship between presence of virus and the disease has not been fully determined. In this study we show that the Atlantic salmon reovirus (ASRV), identical to PRV, can be passaged in GF-1 cells and experimental challenge of naïve Atlantic salmon with cell culture passaged reovirus results in cardiac and skeletal muscle pathology typical of HSMI with onset of pathology from 6 weeks, peaking by 9 weeks post challenge. ASRV replicates in heart tissue and the peak level of virus replication coincides with peak of heart lesions. We further demonstrate mRNA transcript assessment and in situ characterization that challenged fish develop a CD8+ T cell myocarditis.

Acute viral myopericarditis presenting as a transient effusive-constrictive pericarditis caused by coinfection with coxsackieviruses A4 and B3

Acute myopericarditis is usually caused by viral infections, and the most common cause of viral myopericarditis is coxsackieviruses. Diagnosis of myopericarditis is made based on clinical manifestations of myocardial (such as myocardial dysfunction and elevated serum cardiac enzyme levels) and pericardial (such as inflammatory pericardial effusion) involvement. Although endomyocardial biopsy is the gold standard for the confirmation of viral infection, serologic tests can be helpful. Conservative management is the mainstay of treatment in acute myopericarditis. We report here a case of a 24-year-old man with acute myopericarditis who presented with transient effusive-constrictive pericarditis. Echocardiography showed transient pericardial effusion with constrictive physiology and global regional wall motion abnormalities of the left ventricle. The patient also had an elevated serum troponin I level. A computed tomogram of the chest showed pericardial and pleural effusion, which resolved after 2 weeks of supportive treatment. Serologic testing revealed coxsackievirus A4 and B3 coinfection. The patient received conservative medical treatment, including nonsteroidal anti-inflammatory drugs, and he recovered completely with no complications.

Myopericarditis during a primary Epstein-Barr virus infection in an otherwise healthy young adult. An unusual and insidious complication. Case report and a 60-year literature review

An otherwise healthy young man had infectious mononucleosis detected after an atypical clinical onset, including myocarditis and pericarditis. Our patient slowly but completely recovered from his cardiac complications after the course of his primary Epstein-Barr infection, as shown by periodical electrocardiographic and ultrasonographic studies, and a simple treatment with aspirin alone. Our case report is briefly reported, and discussed with regard to the existing literature, which has recorded such complications since the mid 1940s.

[Relationship between endothelial-to-mesenchymal transition and cardiac fibrosis in acute viral myocarditis]

OBJECTIVE

To investigate the relationship between endothelial-to-mesenchymal transition (EndMT) and myocardial fibrosis in acute viral myocarditis (VMC).

METHODS

Twenty-eight Balb/c mice were randomized into 3 groups: control group (n=8), VMC group(n=10) and intervention group(n=10). Mice in VMC and intervention groups were injected intraperitoneally(i.p) with single dose of coxsackievirus B3, mice in control group were injected with equal amount of viral-free vehicle. In the following day, mice in control and VMC groups were injected i.p with 0.1 ml of saline and intervention group with 0.1 ml of recombinant human bone morphogenetic protein 7(rh-BMP7) at a concentration of 300 μg/kg. The mice hearts were harvested after 7 d, cardiac collagen volume fraction (CVF) was calculated on picrosirius red-stained sections. mRNA and protein expression of TGF-β1, CD31, VE-cadherin, fibroblast special protein 1 (FSP-1) and α-smooth muscle actin (α-SMA) and collagen 1α1 in myocardiac tissues were detected by real-time RT-PCR and Western blot analysis, respectively.

RESULTS

Compared to controls, overt fibrosis was presented in necrotic area of myocardium in VMC group. Meanwhile, marked increase of TGF-β1 expression accompanied with EndMT characterized by loss of endothelial phenotype (decreased expression of CD31 and VE-cadherin), gain of mesenchymal proteins (overexpression of FSP-1 and α-SMA) and increased synthesis of collagen was also demonstrated. Both EndMT and cardiac fibrosis were simultaneously reversed by TGF-β1 inhibition.

CONCLUSION

EndMT is involved in cardiac fibrosis in acute viral myocarditis, TGF-β1 might be a main mediator.

[Role of triggering receptor expressed on myeloid cells-1 on coxsackievirus B3-induced inflammation and cardiomyocyte injury]

OBJECTIVE

To determine the expression of TREM-1 (triggering receptor expressed on myeloid cells-1) in macrophages after coxsackievirus B3 (CVB3) infection and the cardiomyocytes viability after culturing with supernatant of macrophages in the absence and presence of TREM-1 inhibitor LP-17 to explore if TREM-1 is involved in the pathogenesis of CVB3 infection induced inflammation and cardiomyocytes injury.

METHODS

TREM-1 mRNA and TREM-1 and DAP-12 protein expression in macrophages were detected by Real-time PCR at 0, 1, 4, 8 and 12 h and by Western blot at 0, 16, 24 and 48 h post CVB3 infection. TNF-α secretion of macrophages was measure by ELISA, vitality and the apoptosis degree of cardiomyocytes was assessed by CCK8 and Annexin V-FITC after the cardiomyocytes were cultured with the supernatant of macrophages in normal control group, CVB3 infection group and LP-17 pretreated CVB3 infection group.

RESULTS

TREM-1 mRNA expression was significantly upregulated at 4, 8, and 12 h (peaked at 8 h) and TREM-1 protein expression was significantly upregulated at 16 and 24 h and returned to baseline level at 48 h after CVB3 infection. The protein expression of DAP-12, a direct downstream signaling molecule of TREM-1, also significantly increased at 24 and 48 h post CVB3 infection (P < 0.01). Level of macrophages secreted TNF-α post CVB3 infection was significantly reduced in LP-17 pretreated cells (P < 0.01), LP-17 pretreatment also significantly improved viability and significantly reduced apoptosis of cardiomyocytes cultured with supernatant of CVB3 infected macrophages (P < 0.01).

CONCLUSION

TREM-1 might be an important mediator post CVB3 infection and a major player on inducing excess macrophages-related inflammation and resulting in an indirect injury to cardiomyocytes.

[Item selection analysis based on quality of life scale in patients with viral myocarditis]

OBJECTIVE

To further select the items based on the pre-test version of quality of life scale in patients with viral myocarditis.

METHODS

Totally 100 patients with viral myocarditis were enrolled in this study. Methodologies including frequency distribution, discrete trend, t-test, Cronbach's α coefficient, correlation coefficient and factor analysis were applied to select items from different perspectives.

RESULTS

A total of 17 items were selected by frequency distribution method from the perspective of central tendency, 15 items were selected by discrete trend method from the perspective of sensitivity, 16 items were selected by t-test method from the perspective of sensitivity and discrimination, 16 items were selected by Cronbach's α coefficient method from the perspective of internal consistency, 12 items were selected by correlation coefficient method from the perspective of representation and independence, and 18 items were selected by factor analysis method from the perspective of representation.

CONCLUSION

Item selection of quality of life scale in patients with viral myocarditis was successfully conducted based on the clinical epidemiological data using a variety of statistical methods.

Green fluorescent protein (GFP) color reporter gene visualizes parvovirus B19 non-structural segment 1 (NS1) transfected endothelial modification

Background

Human Parvovirus B19 (PVB19) has been associated with myocarditis putative due to endothelial infection. Whether PVB19 infects endothelial cells and causes a modification of endothelial function and inflammation and, thus, disturbance of microcirculation has not been elucidated and could not be visualized so far.

Methods and Findings

To examine the PVB19-induced endothelial modification, we used green fluorescent protein (GFP) color reporter gene in the non-structural segment 1 (NS1) of PVB19. NS1-GFP-PVB19 or GFP plasmid as control were transfected in an endothelial-like cell line (ECV304). The endothelial surface expression of intercellular-adhesion molecule-1 (CD54/ICAM-1) and extracellular matrix metalloproteinase inducer (EMMPRIN/CD147) were evaluated by flow cytometry after NS-1-GFP or control-GFP transfection. To evaluate platelet adhesion on NS-1 transfected ECs, we performed a dynamic adhesion assay (flow chamber). NS-1 transfection causes endothelial activation and enhanced expression of ICAM-1 (CD54: mean±standard deviation: NS1-GFP vs. control-GFP: 85.3±11.2 vs. 61.6±8.1; P<0.05) and induces endothelial expression of EMMPRIN/CD147 (CD147: mean±SEM: NS1-GFP vs. control-GFP: 114±15.3 vs. 80±0.91; P<0.05) compared to control-GFP transfected cells. Dynamic adhesion assays showed that adhesion of platelets is significantly enhanced on NS1 transfected ECs when compared to control-GFP (P<0.05). The transfection of ECs was verified simultaneously through flow cytometry, immunofluorescence microscopy and polymerase chain reaction (PCR) analysis.

Conclusions

GFP color reporter gene shows transfection of ECs and may help to visualize NS1-PVB19 induced endothelial activation and platelet adhesion as well as an enhanced monocyte adhesion directly, providing in vitro evidence of possible microcirculatory dysfunction in PVB19-induced myocarditis and, thus, myocardial tissue damage.

Cyclophilin A affects inflammation, virus elimination and myocardial fibrosis in coxsackievirus B3-induced myocarditis

Extracellular cyclophilin A (CyPA) and its receptor Extracellular Matrix Metalloproteinase Inducer (EMMPRIN, CD147) modulate inflammatory processes beyond metalloproteinase (MMP) activity. Recently, we have shown that CyPA and CD147 are upregulated in patients with inflammatory cardiomyopathy. Here we investigate the role of CyPA and CD147 in murine coxsackievirus B3 (CVB3)-induced myocarditis. CVB3-infected CyPA(-/-) mice (129S6/SvEv) revealed a significantly reduced T-cell and macrophage recruitment at 8 days p.i. compared to wild-type mice. In A.BY/SnJ mice, treatment with the cyclophilin-inhibitor NIM811 was associated with a reduction of inflammatory lesions and MMP-9 expression but with enhanced virus replication 8 days p.i. At 28 days p.i. the extent of lesion areas was not affected bei NIM811, whereas the collagen content was reduced. Initiation of NIM811-treatment on day 12 (after an effective virus defense) resulted in an even more pronounced reduction of myocardial fibrosis. In conclusion, in CVB3-induced myocarditis CyPA is important for macrophage and T cell recruitment and effective virus defense and may represent a pharmacological target to modulate myocardial remodeling in myocarditis.

Antiviral activity of coxsackievirus B3 3C protease inhibitor in experimental murine myocarditis

BACKGROUND

We investigated the efficacy of a 3C protease inhibitor (3CPI) in a murine coxsackievirus B3 (CVB3) myocarditis model. CVB3 is a primary cause of viral myocarditis. The CVB3 genome encodes a single polyprotein that undergoes a series of proteolytic events to produce several viral proteins. Most of this proteolysis is catalyzed by the 3C protease (3CP).

METHODS AND RESULTS

By way of a micro-osmotic pump, each mouse received 50 mM 3CPI in 100 μL of 100% dimethyl sulfoxide (DMSO) during a 72-hour period. On the day of pump implantation, mice (n = 40) were infected intraperitoneally with 10(6) plaque-forming units of CVB3. For the infected controls (n = 50), the pump was filled with 100% DMSO without 3CPI. The 3-week survival rate of 3CPI-treated mice was significantly higher than that of controls (90% vs 22%; P < .01). Myocardial inflammation, viral titers, and viral RNA levels were also reduced significantly in the 3CPI-treated group compared with these measures in the controls.

CONCLUSIONS

The protein-based drug 3CPI inhibited the activity of 3CP of CVB3, significantly inhibited viral proliferation, and attenuated myocardial inflammations, subsequent fibrosis, and CVB3-induced mortality in vivo. Thus, this CVB3 3CPI has the potential to be a novel therapeutic agent for the treatment of acute viral myocarditis during the viremic phase.

Pathogenesis of coxsackievirus B3-induced myocarditis: role of macrophage migration inhibitory factor

BACKGROUND

Macrophage migration inhibitory factor (MIF) is an upstream regulator in immune and inflammatory responses. However, its role in viral myocarditis remains unknown. In this study, we investigated the role of the MIF in coxsackievirus B3 (CVB3)-induced myocarditis.

METHODS

Mice were randomized into two groups receiving either Eagle's minimal essential medium (EMEM, control group) or virus solution (infected group). Subsets of mice in the infected group were sacrificed on days 3, 7, 14 and 28 after inoculation. Expression of MIF was detected using an enzyme-linked immunosorbent assay (ELISA), reverse transcription polymerase chain reaction and immunohistochemistry. A neutralizing antibody (Ab) to MIF was injected intraperitoneally from day 0 to 7 after inoculation. Disease severity was estimated by histopathology of the heart and by the heart weight to body weight ratio, and the interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α) in the myocardium were measured by ELISA on day 14.

RESULTS

The serum MIF concentration and expression levels of myocardial MIF mRNA and protein were significantly elevated in mice on days 7 and 14 post-infection. The survival rate was markedly higher and disease severity was obviously less in mice treated with anti-MIF Ab. Furthermore, MIF blockade significantly decreased the IL-1β and TNF-α in the myocarditic heart.

CONCLUSION

These results demonstrate that MIF is an important naturally occurring inflammatory cytokine in CVB3-induced myocarditis, and anti-MIF Ab may lessen the inflammatory response.

Human cardiac-derived adherent proliferating cells reduce murine acute Coxsackievirus B3-induced myocarditis

Background

Under conventional heart failure therapy, inflammatory cardiomyopathy typically has a progressive course, indicating a need for alternative therapeutic strategies to improve long-term outcomes. We recently isolated and identified novel cardiac-derived cells from human cardiac biopsies: cardiac-derived adherent proliferating cells (CAPs). They have similarities with mesenchymal stromal cells, which are known for their anti-apoptotic and immunomodulatory properties. We explored whether CAPs application could be a novel strategy to improve acute Coxsackievirus B3 (CVB3)-induced myocarditis.

Methodology/Principal Findings

To evaluate the safety of our approach, we first analyzed the expression of the coxsackie- and adenovirus receptor (CAR) and the co-receptor CD55 on CAPs, which are both required for effective CVB3 infectivity. We could demonstrate that CAPs only minimally express both receptors, which translates to minimal CVB3 copy numbers, and without viral particle release after CVB3 infection. Co-culture of CAPs with CVB3-infected HL-1 cardiomyocytes resulted in a reduction of CVB3-induced HL-1 apoptosis and viral progeny release. In addition, CAPs reduced CD4 and CD8 T cell proliferation. All CAPs-mediated protective effects were nitric oxide- and interleukin-10-dependent and required interferon-γ. In an acute murine model of CVB3-induced myocarditis, application of CAPs led to a decrease of cardiac apoptosis, cardiac CVB3 viral load and improved left ventricular contractility parameters. This was associated with a decline in cardiac mononuclear cell activity, an increase in T regulatory cells and T cell apoptosis, and an increase in left ventricular interleukin-10 and interferon-γ mRNA expression.

Conclusions

We conclude that CAPs are a unique type of cardiac-derived cells and promising tools to improve acute CVB3-induced myocarditis.

A report of 2 cases of myopericarditis after Vaccinia virus (smallpox) immunization

BACKGROUND

To counter the possibility of smallpox being used as a biological weapon, in 2002 the US government restarted a smallpox vaccination campaign. Myopericarditis is a possible cardiac complication of smallpox vaccination. We report 2 cases of vaccine-associated myopericarditis in military recruits who were treated at our facility. Chest pain, shortness of breath, and electrocardiographic changes of pericarditis, with a recent history of smallpox vaccination, were useful in making the diagnosis of probable post-vaccinial myopericarditis. Nonsteroidal, anti-inflammatory drugs (NSAIDs) were used to manage myopericarditis. Both patients had complete resolution of symptoms and electrocardiographic changes and subsequently returned to active duty.

CONCLUSION

Myopericarditis should be suspected when patients with recent history of smallpox vaccination present with chest pain or shortness of breath. Nonsteroidal anti-inflammatory drugs are useful in the management of post-vaccinial myopericarditis.

[Alteration of interleukin-17/interferon-γ double positive cells in mice with Coxsackie virus induced myocarditis]

OBJECTIVE

To observe the alteration of interleukin-17 and interferon-γ double positive cells (IL-17(+)/IFN-γ(+) cells) in mice with coxsackie virus B3 (CVB3) induced acute viral myocarditis (VMC).

METHODS

VMC was induced in male Balb/c mice by peritoneal injection of CVB3. Control mice received PBS injection. At 0, 1, 2, 3, 4 and 6 weeks after injection, pathological scores were determined on hematoxylin-eosin stained heart sections and flow cytometric analysis was performed to evaluate the percent of IL-17(+)/IFN-γ(+) cells among CD4(+) T cells.

RESULTS

Compared to control mice, the pathological scores of VMC mice were higher on CVB3 infection week 1 (1.8 ± 0.5), peaked on week 2 (2.8 ± 0.5) and declined thereafter. However, the proportion of IL-17(+)/IFN-γ(+) cells remained steadily at a low level throughout the observation period and was similar between VMC and control mice.

CONCLUSIONS

Our data shows that IL-17(+)/IFN-γ(+) cells might not be involved in the inflammation process of CVB3 induced VMC mice model.

Cardiac-related varicella mortality in childhood: a literature review with clinical experience

Among unvaccinated populations, primary varicella zoster virus (VZV) infection results in a minor childhood illness for the majority of individuals. Mortality is rare, and fatalities associated with cardiac complications are exceptional. In a population where routine VZV vaccination is not practised, we report a death in a previously healthy child secondary to VZV myocarditis. A literature review of cardiac-related VZV mortality in childhood is included. This identified a further 13 cases where death was associated with or attributable to, direct involvement of the myocardium or conducting system with what is frequently considered a benign childhood illness.

Shortness of breath in a CF patient: not always the chest

The authors report the case of an adult with cystic fibrosis (CF) presenting with an episode of acute shortness of breath during an inpatient stay for infective exacerbation of CF. The treatment of bronchodilators and steroids for presumed airways disease was not effective and on review of the chest x-ray, it showed some evidence of pulmonary oedema. An echo showed a dilated left ventricle and globally reduced function. Serology came back positive for enterovirus which was in keeping with a diagnosis of myocarditis.

[Myocardial morphological changes in atrial fibrillation]

Hearts of 21 died patients with ischemic heart disease (IHD) have been studied by histlological and morphometrical methods. The atrial auricles derived after operation of 66 patients with heart diseases and IHD have been researched by automatic semiquantitative and immunohistochemical techniques. In general atrial fibrillation (AF) has been evident in chronic myocarditis probably conditioned by viral infections. In quantity of observations enterovirus and parvovirus B19 antigens have been found out in myocardium. In 18% studied myocardium antigen of adenovirus has been established. The result of myocarditis has been fibrosis and adiposis. In myocardium of patients with AF diffuse amyloidosis has been abundant. Amyloid depots have been established in perimuscular stroma, under endocardium, in vascular walls and cardiac hystiocyte. The group of patients with paroxysmal AF has differed from the group of stable AF by fibrosis degree.

Inflammatory skin and bowel disease linked to ADAM17 deletion

We performed genetic and immunohistochemical studies in a sister and brother with autosomal recessive neonatal inflammatory skin and bowel lesions. The girl died suddenly at 12 years of age from parvovirus B19-associated myocarditis; her brother had mild cardiomyopathy. We identified a loss-of-function mutation in ADAM17, which encodes a disintegrin and metalloproteinase 17 (also called tumor necrosis factor α [TNF-α]-converting enzyme, or TACE), as the probable cause of this syndrome. Peripheral-blood mononuclear cells (PBMCs) obtained from the brother at 17 years of age showed high levels of lipopolysaccharide-induced production of interleukin-1β and interleukin-6 but impaired release of TNF-α. Despite repeated skin infections, this young man has led a relatively normal life. (Funded by Barts and the London Charity and the European Commission Seventh Framework Programme.).

Pharmacological and biological antiviral therapeutics for cardiac coxsackievirus infections

Subtype B coxsackieviruses (CVB) represent the most commonly identified infectious agents associated with acute and chronic myocarditis, with CVB3 being the most common variant. Damage to the heart is induced both directly by virally mediated cell destruction and indirectly due to the immune and autoimmune processes reacting to virus infection. This review addresses antiviral therapeutics for cardiac coxsackievirus infections discovered over the last 25 years. One group represents pharmacologically active low molecular weight substances that inhibit virus uptake by binding to the virus capsid (e.g., pleconaril) or inactivate viral proteins (e.g., NO-metoprolol and ribavirin) or inhibit cellular proteins which are essential for viral replication (e.g., ubiquitination inhibitors). A second important group of substances are interferons. They have antiviral but also immunomodulating activities. The third and most recently discovered group includes biological and cellular therapeutics. Soluble receptor analogues (e.g., sCAR-Fc) bind to the virus capsid and block virus uptake. Small interfering RNAs, short hairpin RNAs and antisense oligonucleotides bind to and led to degradation of the viral RNA genome or cellular RNAs, thereby preventing their translation and viral replication. Most recently mesenchymal stem cell transplantation has been shown to possess antiviral activity in CVB3 infections. Taken together, a number of antiviral therapeutics has been developed for the treatment of myocardial CVB infection in recent years. In addition to low molecular weight inhibitors, biological therapeutics have become promising anti-viral agents.

[Experimental study on expression of connective tissue growth factor in viral myocarditis in mice]

OBJECTIVE

To study the expression of connective tissue growth factor (CTGF) in the myocardial tissue of mice with viral myocarditis (VMC).

METHOD

Balb/c mice were infected with coxsackie virus B3 (CVB3) to establish VMC model. The mice were divided into control group (n = 50) and VMC group (n = 50). on days 4, 7, 14 and 21 after infection, heart specimens of 8 mice were randomly taken and examined after HE staining for myocardial necrosis and cellular infiltration. The area of positive Masson stained myocardium collagen fibers was measured, and collagen volume fraction (CVF) was measured. Then the level of serum creatine phosphokinase-MB (CKMB) was determined. The levels of CTGF and TGF-β₁ were detected by streptavidin peroxidase immunoperoxidase technique. Expression of CTGF and TGF-β₁ were detected with reverse transcription-polymerase chain reaction (RT-PCR). At the same time, the correlations were analyzed.

RESULT

(1) The level of CKMB peaked on day 7, and decreased afterwards (455.45 ± 37.95, 606.95 ± 35.64, 573.62 ± 42.90, 308.60 ± 20.49, respectively, 4 - 21 d points), in which 4, 7, 14 d points, there was significant difference compared with control group (t = 6.144, 12.558, 11.182, respectively, P < 0.01). (2) CVF increased significantly on day 14 (8.22 ± 1.95, t = 4.486, P < 0.01) and day 21 (9.46 ± 1.87, t = 4.486, P < 0.01) in VMC group. (3) Measured by streptavidin peroxidase immunoperoxidase technique, the levels of CTGF (171.50 ± 10.25, 141.70 ± 10.863, 110.35 ± 11.051, 81.05 ± 10.190, respectively, 4 - 21 d points) and TGF-β₁ (184.90 ± 11.480, 150.25 ± 9.915, 103.50 ± 10.455, 84.15 ± 9.848, respectively, 4 - 21 d points) increased after day 4 in VMC (P < 0.01). (4) Measured by RT-PCR, the expression of CTGF mRNA and TGF-β₁ increased in VMC group, and the increase was enhanced with the disease development (P < 0.01). (5) The expression of CTGF and TGF-β₁ was positively linearly correlated (r = 0.987, P < 0.01), the expression of CTGF was negatively correlated with CVF (r = -0.901, P < 0.01), but the expression of CTGF was detected earlier than myocardial fibrosis.

CONCLUSION

The increase of CTGF expression was associated with the severity of myocardial fibrosis in VMC. These results suggest that abnormal expression of CTGF may take part in the development of fibrosis in VMC.

Impairment of immunoproteasome function by β5i/LMP7 subunit deficiency results in severe enterovirus myocarditis

Proteasomes recognize and degrade poly-ubiquitinylated proteins. In infectious disease, cells activated by interferons (IFNs) express three unique catalytic subunits β1i/LMP2, β2i/MECL-1 and β5i/LMP7 forming an alternative proteasome isoform, the immunoproteasome (IP). The in vivo function of IPs in pathogen-induced inflammation is still a matter of controversy. IPs were mainly associated with MHC class I antigen processing. However, recent findings pointed to a more general function of IPs in response to cytokine stress. Here, we report on the role of IPs in acute coxsackievirus B3 (CVB3) myocarditis reflecting one of the most common viral disease entities among young people. Despite identical viral load in both control and IP-deficient mice, IP-deficiency was associated with severe acute heart muscle injury reflected by large foci of inflammatory lesions and severe myocardial tissue damage. Exacerbation of acute heart muscle injury in this host was ascribed to disequilibrium in protein homeostasis in viral heart disease as indicated by the detection of increased proteotoxic stress in cytokine-challenged cardiomyocytes and inflammatory cells from IP-deficient mice. In fact, due to IP-dependent removal of poly-ubiquitinylated protein aggregates in the injured myocardium IPs protected CVB3-challenged mice from oxidant-protein damage. Impaired NFκB activation in IP-deficient cardiomyocytes and inflammatory cells and proteotoxic stress in combination with severe inflammation in CVB3-challenged hearts from IP-deficient mice potentiated apoptotic cell death in this host, thus exacerbating acute tissue damage. Adoptive T cell transfer studies in IP-deficient mice are in agreement with data pointing towards an effective CD8 T cell immune. This study therefore demonstrates that IP formation primarily protects the target organ of CVB3 infection from excessive inflammatory tissue damage in a virus-induced proinflammatory cytokine milieu.

Synergy of molecular and serological methods in minimally invasive diagnosis of enteroviral cardiac infection

Treatment of myocarditis and pericarditis can differ on the basis of aetiology: systemic or auto-immune disease can be positively influenced by corticoid therapy, whereas this kind of treatment can worsen the course of virus-induced disease. Therefore, the aetiological diagnosis is extremely important. The synergistic use of minimally invasive serological, IgG, IgM, IgA, and neutralizing titres, and RNA detection was evaluated on representative patients out of 238 suffering from cardiopathies. The results obtained for each case can yield reliable guidelines that rapidly highlight the presence of a viral aetiology so that an endomyocardial biopsy can be performed thus eliminating incorrect therapies. Thus, not only is this technique rapid, minimally invasive providing the clinician with decisive data, but it is cost effective for the health system.

Selenium deficiency contributes to the chronic myocarditis in coxsackievirus-infected mice

Both coxsackievirus B3 (CVB3) infection and selenium (Se) deficiency play a pivotal role in Keshan disease of the heart. The Se deficiency was known to contribute to the CVB3-induced myocarditis in acute and subacute phase of infection. However, its effect on the myocarditis in chronic phase of infection has not been examined yet. To address this question, we kept mice on a Se-replete or Se-deficient diet for 28 days, infected them intraperitoneally with CVB3 and maintaining previous diets, we examined them for next 90 days for several parameters indicative of the infection or disease. We found out that the mice on the Se-deficient diet exhibited a higher mortality, lower serum glutathione peroxidase (GPx) activity, evident histopathological changes indicative of myocarditis, and a higher level of viral RNA in the heart. Summing up, these data suggest that the Se-deficiency creates a chronic myocarditis-prone condition by fostering the active virus replication.

Acute fulminant myocarditis and the 2009 pandemic influenza A virus (H1N1)

The 2009 Pandemic Novel Influenza A [HIN1] resulted in mild disease mostly but severe cases and death were associated with pneumonia, respiratory failure and multi-organ failure. We present a case of severe disease with acute heart failure and arrhythmia due to fulminant myocarditis in a 50- year old obese man with diabetes mellitus.