Inhibition of coxsackievirus infection in cardiomyocytes by small dsRNA targeting its cognate coxsackievirus adenovirus receptor.

Background & objectives: Coxsackievirus B (CVB), a member of human Enterovirus group, is the most common cause of viral myocarditis. Coxsackievirus adenovirus receptor (CAR) is identified as a key determinant for the entry of CVB in the target cells. Thus, blockade of receptor by RNA interference (RNAi) may inhibit the entry and pathogenesis of CVB in cardiac cells. The present study was aimed to determine the effect of CAR small dsRNA (siRNA) on coxsackieviral load and CAR expression in coxsackievirus-infected cardiomyocytes. Methods: Transfection efficiency in rat cardiomyocytes (H9c2) was determined by the fluorescent microscopy and flow cytometry. CAR siRNA dose was optimized based on cell viability and relative CAR messenger RNA (mRNA) expression. Cardiomyocytes were transfected with CAR siRNA followed by infection with 100 multiplicity of infection of CVB, which were harvested after 24, 48 and 72 h post-infection (p.i.). RNA was extracted for relative CAR mRNA expression. Cells were freeze-thawed thrice for estimating coxsackieviral load. Results: The efficiency of transfection was optimized to be >80 per cent and CAR siRNA dose of 60 pmol was standardized. The knockdown of CAR by siRNA decreased its expression twice the expression in normal cardiomyocytes after 24 h p.i. of CVB. The treatment with CAR siRNA resulted in significant two log reduction of CVB load in cardiomyocytes infected with CVB at 24 h p.i. and retained till 72 h p.i. Interpretation & conclusions: The inhibition of CAR by siRNA was found to be effective against CVB in cardiomyocytes. However, this treatment strategy has to be evaluated in vivo to develop a new treatment strategy for patients suffering with viral myocarditis.

Role of coxsackievirus and adenovirus receptor (CAR) expression and viral load of adenovirus and enterovirus in patients with dilated cardiomyopathy.

Enteroviruses (EVs) and adenoviruses (AdVs) are two important etiological agents of viral myocarditis and dilated cardiomyopathy (DCM). Both these viruses share a common receptor, the coxsackievirus and adenovirus receptor (CAR), for their infection. However, the role of viral load and CAR expression in disease severity has not yet been completely elucidated. The present study aimed to determine viral load of EV and AdV in DCM patients and correlate them with the level of CAR expression in these patients. Sixty-three DCM cases and 30 controls, each of whom died of heart disease other than DCM and non-cardiac disease respectively, were included. Viral load was determined by TaqMan real-time PCR using primers and probes specific for the AdV hexon gene and the 5'UTR region of EV. The CAR mRNA level was semi-quantitated by RT-PCR, and antigen expression was studied by immunohistochemistry. A significantly high AdV load (p < 0.05) and CAR expression (p < 0.05) were observed in DCM cases versus controls, whereas the EV load showed no significant difference. The data suggests a clinical threshold of 128 AdV copies/500 ng of DNA for DCM, with 66.7 % sensitivity and 65 % specificity. A positive correlation between AdV load and CAR expression (p < 0.001) was also observed in DCM cases. The high adenoviral load and increased CAR expression in DCM and their association with adverse disease outcome indicates role of both virus and receptor in disease pathogenesis. Thus, the need for targeting both the virus and the receptor for treatment of viral myocarditis and early DCM requires further confirmation with larger studies.

Clinical applicability of various dengue diagnostic tests in resource-limited endemic settings.

INTRODUCTION: Dengue is one of the most important arboviral infections caused by one of the four dengue serotypes, 1-4. OBJECTIVE: To study the applicability of different diagnostic methods in diagnosis of dengue viral infection. MATERIALS AND METHODS: A total of 2101 blood samples were collected for confirmation of dengue viral infection. All the samples were tested by dengue-specific IgM ELISA, of which 111 were also tested for NS1 antigen detection and 27 acute samples (≤5 days) were further subjected for viral RNA detection by RT-PCR and isolation in C6/36 cell line. To detect the sensitivity of NS1 antigen for different dengue virus serotypes, four dengue serotype 1 and 12 dengue 3 were subjected for the NS1 antigen assay. RESULTS: Most common age group affected was 16-45 years, with male to female ratio of 2.8:1. During first 3 days of illness virus isolation and RT-PCR were the most sensitive (83%) followed by NS1 antigen detection (75%) and IgM detection (37.5%). The positivity of IgM detection was found to be significantly higher as compared to NS1 detection during 4 to 5 days and also after 5 days of illness (P < 0.05). Dengue serotypes 1 and 3 were found to be co-circulated, dengue 1 being the predominant serotype. CONCLUSION: Virus isolation and RT-PCR were the most sensitive tests during the early period of illness whereas beyond third day, IgM antibody detection was found to be the most sensitive method of dengue diagnosis.

Persistence of human parvovirus B19 in tissues from adult individuals: a comparison with serostatus and its clinical utility.

Human parvovirus B19 (PVB19) is linked to variety of diseases, including erythema infectiosum, transient aplastic crisis, fetal hydrops, cardiomyopathy and, recently, hepatitis and arthritis. Persistence of PVB19 in asymptomatic individuals has been reported in skin, synovium, myocardium and bone marrow. A higher level of PVB19 DNA has been observed in various tissues from cases of disease than in controls. Simultaneously, equal detection of PVB19 DNA has been shown in both cases and controls. Thus, it has become fundamental to study PVB19 DNA persistence in tissues that are unaffected by disease. This will help to better understand PVB19 DNA persistence in symptomatic and asymptomatic individuals and its possible pathogenic role in various diseases. A total of 70 adult autopsies were included and divided into seropositive (SP) and seronegative (SN) groups based on PVB19 IgG. Nested PCR for PVB19 DNA was carried out in myocardium, liver, kidney, and bone marrow. Of the 70 patients, 60% belonged to the SP group and 40% to the SN group. Seropositivity ranged from 50% in the 12 to 20 year old group to 66.7% in the 61 to 80 year old group. The viral genome was detected in 34.3% of myocardium, 20% of bone marrow, 10% of kidney and 8.6% of liver samples. There was no significant difference in the persistence rates between the SP and SN groups. The persistence of PVB19 DNA in various tissues ranged from 8.3% to 36% in the SP group and 10% to 30% in the SN group. The persistence of PVB19 DNA in all the tissues was low, and PVB19 serostatus had no influence on the persistence of PVB19 DNA.

Disseminated coxsackievirus B fulminant myocarditis in an immunocompetent adult: a case report: case of disseminated coxsackievirus myocarditis.

Coxsackieviral myocarditis is associated with systemic involvement in neonates; however, fulminant coxsackieviral myocarditis is rare in adults, and its dissemination with fatal myocarditis involving kidneys, liver, and adrenal is further rarely reported. We report a case of fulminant myocarditis along with dissemination of coxsackievirus, which was clinically unrecognized.

Genotyping and subtyping of mumps virus isolates from the Indian subcontinent.

Mumps is a vaccine-preventable disease that usually occurs as a self-limiting parotitis, but it can also lead to several life-threatening complications, including pancreatitis, meningitis, and encephalitis. The molecular epidemiology of the virus is poorly understood. The present study describes an outbreak of mumps virus infection in Punjab, India. The etiology was confirmed by serology and RNA detection to be mumps virus in 72 % of the cases and 50 % of contacts. This study, for the first time, revealed the mumps virus genotypes circulating in the Indian subcontinent as subtype G2 of genotype G.

Ribonucleic acid extraction from archival formalin fixed paraffin embedded myocardial tissues for gene expression and pathogen detection.

INTRODUCTION: Archival tissue samples preserved in formalin are a great source of treasure for biomedical research and diagnostics. Formalin, though is a good preservative, causes the modification of nucleic acid limiting the application of fixed tissues. The present study evaluated three methods of RNA extraction for constitutive gene expression and pathogen detection. MATERIAL AND METHODS: Sixteen archival formalin-fixed paraffin-embedded (FFPE) myocardial tissues were subjected to RNA extraction by Trizol, SDS, and RNeasy FFPE kit followed by RT-PCR and Taqman Real-Time PCR to study the expression of housekeeping genes. RESULTS: RNA was extracted from all 16 myocardial tissues (100%) by RNeasy FFPE kit, as compared to 14/16 by Trizol and 8/10 by SDS methods. The expression of Glyceraldehyde-3-phosphate dehydrogenase (GAPDH)was observed in RNA extracted by RNeasy FFPE kit and Trizol. High yield of RNA was obtained by RNeasy FFPE kit than Trizol (P = 0.002) and SDS(P = 0.012). Of the three methods, RNeasy FFPE kit was evaluated for Enterovirus RNA detection in 16 other histopathologically confirmed FFPE tissues of dilated cardiomyopathy (DCM) cases and Enterovirus genome was detected in 4/16 (25%) FFPE tissues of DCM cases. The enteroviral sequences of the viral isolates revealed 99% homology with Human coxsackievirus B5. CONCLUSION: The Qiagen RNeasy FFPE kit resulted in significantly high reproducibility of RNA from FFPE myocardial tissues, which are suitable for amplification by Taq-Man Real-Time and RT-PCR. Thus, the results show that these FFPE tissues can be used for gene expression, pathogen detection, and epidemiological studies.

Expression of coxsackievirus and adenovirus receptor and its cellular localization in myocardial tissues of dilated cardiomyopathy.

BACKGROUND: Myocarditis and dilated cardiomyopathy (DCM) are common causes of morbidity and mortality in children and adults. Recently, the human coxsackievirus and adenovirus receptor (CAR), a common receptor for coxsackieviruses and adenoviruses, was discovered and its increased expression has been reported in patients with DCM and myocarditis. OBJECTIVE: To measure the expression of CAR in myocardial tissues of patients with DCM and its cellular localization in DCM cases. METHODS: Formalin-fixed myocardial tissues collected during autopsy from 26 cases of DCM, and 20 cases each of noncardiac disease and cardiac disease other than DCM were included as the test group, and control groups A and B, respectively. Expression of CAR was studied using immunohistochemical staining of myocardial tissue with a CAR-specific rabbit polyclonal antibody. CAR messenger RNA was semiquantified by reverse transcription polymerase chain reaction followed by agarose gel analysis and measurement of band intensity. RESULTS: CAR positivity in DCM cases was found to be 96% (25 of 26) compared with 30% in control group A and 40% in control group B. CAR was found to be expressed in myocytes, endothelial and interstitial cells; however, positivity in myocytes was significantly higher than in other cells in all groups. The site of CAR expression was predominantly the sarcolemma along with cytoplasm in cardiomyocytes. CONCLUSIONS: The present study highlighted the increased expression of CAR in DCM cases, with localization in myocytes and endothelial cells.

Utility of multiplex reverse transcriptase-polymerase chain reaction for diagnosis and serotypic characterization of dengue and chikungunya viruses in clinical samples.

The reemergence of chikungunya virus (CHIKV) has compounded the already existing dengue problem because of clinical similarities and common vector, demanding the need for a rapid and specific diagnosis. Thus, dengue chikungunya multiplex reverse transcriptase-polymerase chain reaction (DCmRT-PCR) was developed and validated for simultaneous detection of dengue and chikungunya viral infections and its utility in virus serotyping. Blood samples from 97 suspected dengue and chikungunya cases and 10 healthy controls were subjected to dengue and chikungunya conventional RT-PCR and DCmRT-PCR. Thirty-one of 97 samples were positive for dengue or chikungunya viral RNA by RT-PCR and DCmRT-PCR with 100% concordance. DCmRT-PCR products were cycle sequenced. Seven dengue virus strains were clustered within genotype III of DENV-3 and 4 within genotype III of DENV-1, whereas chikungunya sequences were clustered within the Central/East African genotype. DCmRT-PCR was found to be a potential rapid test for simultaneous detection of dengue and CHIKV in clinical samples along with dengue serotyping.

Clinical applicability of single-tube multiplex reverse-transcriptase PCR in dengue virus diagnosis and serotyping.

This study has evaluated the clinical applicability of a single-tube multiplex RT-PCR as compared with a two-step nested RT-PCR for the diagnosis as well as serotyping of dengue virus in patient's samples. Seventy-six acute phase blood samples collected from clinically suspected dengue patients during the 2008 outbreak were subjected to two-step nested RT-PCR and single-tube multiplex RT-PCR for dengue diagnosis and serotyping. Of the 76 samples, 17 (22.4%) were positive for dengue viral RNA. Single dengue virus infection was found in 16 cases and 1 had concurrent infection with two serotypes (3&1). Dengue serotype 3 was the predominant serotype (70.5%), followed by serotype 1 (23.5%). Single-tube multiplex PCR had concordant result with that of two-step nested RT-PCR including the one with concomitant infection. This study reveals the predominance of dengue serotype 3 in North India in addition to the co-circulation of multiple serotypes and concomitant infection. The rapid and accurate diagnostic capability of single-tube multiplex RT-PCR used in the study appears to be promising enough to be commonly used for dengue viral detection as well as serotyping.