Molecular phenotypes of human parvovirus B19 in patients with myocarditis

AIM:To investigate molecular phenotypes of myocardial B19V-infection to determine the role of B19V in myocarditis and dilated cardiomyopathy(DCM).METHODS:Endomyocardial biopsies(EMBs) from 498 B19V-positive patients with myocarditis and DCMwere analyzed using molecular methods and functional experiments.EMBs were obtained from the University Hospitals of Greifswald and Tuebingen and additionally from 36 German cardiology centers.Control tissues were obtained at autopsy from 34 victims of accidents,crime or suicide.Identification of mononuclear cell infiltrates in EMBs was performed using immunohistological staining.Anti-B19V-IgM and anti-B19V-IgG were analyzed by enzyme-linked immunosorbent assay(ELISA).B19V viral loads were determined using in-house quantitative real-time polymerase chain reaction(PCR).For B19V-genotyping a new B19V-genotype-specific restriction fragment length polymorphism(RFLP)-PCR was established.B19V-genotyping was verified by direct DNAsequencing and sequences were aligned using BLAST and BioEdit software.B19V P6-promoter and HHV6-U94-transactivator constructs were generated for cell culture experiments.Transfection experiments were conducted using human endothelial cells 1.Luciferase reporter assays were performed to determine B19Vreplication activity.Statistical analysis and graphical representation were calculated using SPSS and Prism5 software.RESULTS:The prevalence of B19V was significantly more likely to be associated with inflammatory cardiomyopathy(iCMP) compared to uninflamed DCM(59.6% vs 35.3%)(P < 0.0001).The detection of B19V-mRNA replication intermediates proved that replication of B19V was present.RFLP-PCR assays showed that B19V-genotype 1(57.4%) and B19V-genotype 2(36.7%) were the most prevalent viral genotypes.B19V-genotype 2 was observed more frequently in EMBs with iCMP(65.0%) compared to DCM(35%)(P = 0.049).Although there was no significant difference in gender-specific B19V-loads,women were more frequently infected with B19V-genotype 2(44.6%) than men(36.0%)(P = 0.0448).Coinfection with B19V and other cardiotropic viruses was found in 19.2% of tissuesamples and was associated with higher B19V viral load compared to B19V-monoinfected tissue(P = 0.0012).The most frequent coinfecting virus was human herpes virus 6(HHV6,16.5%).B19V-coinfection with HHV6 showed higher B19V-loads compared to B19V-monoinfected EMBs(P = 0.0033),suggesting that HHV6 had transactivated B19V.In vitro experiments confirmed a 2.4-fold increased B19V P6-promoter activity by the HHV6 U94-transactivator.CONCLUSION:The finding of significantly increased B19V loads in patients with histologically proven cardiac inflammation suggests a crucial role of B19V-genotypes and reactivation of B19V-infection by HHV6-coinfection in B19V-associated iCMP.Our findings suggest that B19V-infection of the human heart can be a causative event for the development of an endothelial cell-mediated inflammatory disease and that this is related to both viral load and genotype.

Innate immune receptors in heart failure: Side effect or potential therapeutic target?

Heart failure(HF) is a leading cause of mortality and morbidity in western countries and occasions major expenses for public health systems. Although optimal medical treatment is widely available according to current guidelines, the prognosis of patients with HF is still poor. Despite the etiology of the disease, increased systemic or cardiac activation of the innate immune system is well documented in several types of HF. In some cases there is evidence of an association between innate immune activation and clinical outcome of patients with this disease. However, the few large trials conducted with the use of anti-inflammatory medication in HF have not revealed its benefits. Thus, greater understanding of the relationship between alteration in the immune system and development and progression of HF is urgently necessary: prior to designing therapeutic interventions that target pathological inflammatory processes in preventing harmful cardiac effects of immune modulatory therapy. In this regard, relatively recently discovered receptors of the innate immune system, i.e., namely toll-like receptors(TLRs) and nodlike receptors(NLRs)-are the focus of intense cardiovascular research. These receptors are main up-stream regulators of cytokine activation. This review will focus on current knowledge of the role of TLRs and NLRs, as well as on downstream cytokine activation, and will discuss potential therapeutic implications.

Is hepatic steatosis associated with left ventricular mass index increase in the general population?

AIM To investigate the association between hepatic steatosis and change in left ventricular mass index(LVMI) over five years, and examine whether systolic and diastolic blood pressures are mediators of the association between hepatic steatosis and LVMI using a general population sample.METHODS We analyzed data from the Study of Health in Pomerania. The study population comprised 1298individuals aged 45 to 81 years. Hepatic steatosis was defined as the presence of a hyperechogenic pattern of the liver together with elevated serum alanine transferase levels. Left ventricular mass was determined echocardiographically and indexed to height2.7. Path analyses were conducted to differentiate direct and indirect paths from hepatic steatosis to LVMI encompassing systolic and diastolic blood pressure as potential mediating variables.RESULTS Hepatic steatosis was a significant predictor for all measured echocardiographic characteristics at baseline. Path analyses revealed that the association of hepatic steatosis with LVMI change after five years was negligibly small(β =-0.12, s.e. = 0.21, P = 0.55). Systolic blood pressure at baseline was inversely associated with LVMI change(β =-0.09, s.e. = 0.03, P < 0.01), while no association between diastolic blood pressure at baseline and LVMI change was evident(β = 0.03, s.e. = 0.05, P = 0.56). The effect of the indirect path from hepatic steatosis to LVMI via systolic baseline blood pressure was small(β =-0.20, s.e. = 0.10, P = 0.07). No indirect effect was observed for the path via diastolic baseline blood pressure(β = 0.03, s.e. = 0.06, P = 0.60). Similar associations were observed in the subgroup of individuals not receiving beta-blockers, calcium channel blockers, or drugs acting on the reninangiotensin system.CONCLUSION Baseline associations between hepatic steatosis and LVMI do not extend to associations with LVMI change after five years. More studies are needed to study the longitudinal effects of hepatic steatosis on LVMI.