Antiviral and myocyte protective effects of IL-28A in coxsackievirus B3-induced myocarditis

Objective: This study aimed to investigate whether interleukin-28A (IL-28A) plays a role in murine myocarditis induced by coxsackievirus B3 (CVB3), and to explore its possible mechanism involved. Methods: Male BALB/c mice both infected and not infected by CVB3 were randomly divided into four groups (n = 40), untreated or treated with different doses of IL-28A for 4 days, and then sacrificed on days 4 and 7 post-infection. The heart samples were collected for histopathologic examination. Cardiac viral load was determined by a plaque assay. Additionally, immunoblot analysis, TUNEL assay, and immunohistochemistry were performed to examine the expression of signal transducer, activator of transcription 1 and 2 (STAT1 and STAT2), CVB3-induced apoptosis and the expression of Bcl-2, BAX and Caspase-3. Results: Compared to uninfected mice, the CVB3 infected mice exhibited higher mortality rate (p < 0.001), apparent inflammation and myocardial lesion (p < 0.01), and higher cardiac viral load (p < 0.01). After CVB3 infection, IL-28A treated mice presented no death (p < 0.001), reduced inflammation and myocardial lesion (p < 0.01), and lower viral load (p < 0.01) compared to untreated mice. Besides, treatment with IL-28A markedly increased the expressions of STAT1 and STAT2, and inhibited CVB3-induced apoptosis in myocardial cells with increased ratio of Bcl-2/BAX. Conclusion: The antiviral and myocyte protective effects of IL-28A in CVB3-inducedmyocarditis are regulated by STAT1 and STAT2. .

El corazón endocrino y el proceso inflamatorio / [The endocrine heart and inflammation].

The endocrine heart produces the polypeptide hormones Atrial Natriuretic Factor (ANF or ANP) and Brain Natriuretic Peptide (BNP). Through the peripheral actions of these hormones the heart contributes to the regulation of the cardiac preload and afterload. More recently, new functions for these hormones have been described including the modulation of the immune response. Plasma levels of BNP but not those of ANF, increase following an acute rejection episode of a cardiac allotransplant but return to levels pre-rejection with successful treatment. This observation constitutes the first observation leading to characterizing the interactions of BNP with the immune response. Several other pathologies with an inflammatory component are now known to be associated with an increase in the production of BNP. Such an increase is due to an increase in the transcriptional activity of the BNP gene induced by cytokines and related substances. In vitro investigations have shown that an increase in BNP directly modulates immunological activity. Inflammation and hemodynamic changes co-exist in several cardiovascular diseases and therefore it may be beneficial to measure circulating levels of both ANF and BNP as biomarkers of changes in intravascular volume and of changes in intravascular volume plus inflammation, respectively. Changes in plasma ANF, that are relatively larger than those of BNP, might be an indication of hemodynamic deterioration while important changes in circulating BNP could indicate a worsening of the inflammatory process.

Absence of Fas-L aggravates renal injury in acute Trypanosoma cruzi infection

Trypanosoma cruzi infection induces diverse alterations in immunocompetent cells and organs, myocarditis and congestive heart failure. However, the physiological network of disturbances imposed by the infection has not been addressed thoroughly. Regarding myocarditis induced by the infection, we observed in our previous work that Fas-L-/- mice (gld/gld) have very mild inflammatory infiltration when compared to BALB/c mice. However, all mice from both lineages die in the early acute phase. Therefore, in this work we studied the physiological connection relating arterial pressure, renal function/damage and cardiac insufficiency as causes of death. Our results show that a broader set of dysfunctions that could be classified as a cardio/anaemic/renal syndrome is more likely responsible for cardiac failure and death in both lineages. However, gld/gld mice had very early glomerular deposition of IgM and a more intense renal inflammatory response with reduced renal filtration, which is probably responsible for the premature death in the absence of significant myocarditis in gld/gld.

CC-chemokine receptors: a potential therapeutic target for Trypanosoma cruzi-elicited myocarditis

The comprehension of the pathogenesis of Trypanosoma cruzi-elicited myocarditis is crucial to delineate new therapeutic strategies aiming to ameliorate the inflammation that leads to heart dysfunction, without hampering parasite control. The augmented expression of CCL5/RANTES and CCL3/MIP-1alpha, and their receptor CCR5, in the heart of T. cruzi-infected mice suggests a role for CC-chemokines and their receptors in the pathogenesis of T. cruzi-elicited myocarditis. Herein, we discuss our recent results using a CC-chemokine receptor inhibitor (Met-RANTES), showing the participation of CC-chemokines in T. cruzi infection and unraveling CC-chemokine receptors as an attractive therapeutic target for further evaluation in Chagas disease.