Pathogenesis of coxsackievirus B3-induced myocarditis: role of macrophage migration inhibitory factor / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

Association between myocardial calpain activation and apoptosis in lipopolysaccharide-induced septic mouse model / 中华心血管病杂志

<p><b>OBJECTIVE</b>in septic mice, myocardial calpain was activated and induced caspase-3 activation, the association between calpain activation and apoptosis was explored in this experiment.</p><p><b>METHODS</b>in in vivo model, adult C57 mice were injected with lipopolysaccharide (LPS, 4 mg/kg, i.p.) to induce sepsis. Myocardial calpain and caspase-3 activities, protein levels of calpain-1, calpain-2, calpastatin, Bcl-2 and Bid were detected by Western blot analysis and myocardial apoptosis was detected by TUNEL, myocardiac function was evaluated by Langendorff system. In in vitro model, adult rat cardiomyocytes were incubated with LPS (1 microg/ml) or co-incubated with calpain inhibitor-III (10 micromol/L), calpain activity, caspase-3 activity, protein levels of Bcl-2 and Bid, and cardiomyocyte apoptosis were detected.</p><p><b>RESULTS</b>in septic mice, myocardial calpain and caspase-3 activity were increased up to 2.7- and 1.8-folds, respectively. Both calpain inhibitor-III and PD150606 significantly attenuated the increase of caspase-3 activity. Myocardial protein levels of calpain-1, calpain-2, calpastatin, Bcl-2 and Bid were similar between control and septic mice, and no cleavage of both Bcl-2 and Bid was found in septic mice. Calpain inhibitor-III significantly improved myocardial function in septic mice. In in vitro model, calpain and caspase-3 activities were increased after 4 h LPS treatment, co-treatment with calpain inhibitor-III prevented caspase-3 activity increase, protein Bcl-2 and Bid were similar between normal cardiomyocytes and LPS-treated cardiomyocytes. Cardiomyocyte apoptosis was similar in in vivo and in vitro septic models.</p><p><b>CONCLUSION</b>myocardial calpain activity is increased in LPS induced septic mice, subsequent caspase-3 activation may contribute to myocardial dysfunction in septic mice without aggravating myocardial apoptosis and Bcl-2 and Bid are not involved on calpain induced caspase-3 activation in our model.</p>

Association between expression of chromogranin A and myocardial fibrosis in patients with dilated cardiomyopathy / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the possible correlation between expression of chromogranin A (CGA) and myocardial fibrosis and investigate the potential role of CGA in the development of myocardial fibrosis in patients with dilated cardiomyopathy (DCM).</p><p><b>METHODS</b>Surgical myocardial specimen from 10 DCM patients underwent successful orthotopic cardiac transplantation, and 3 normal myocardial specimen from brain-dead organ donors were obtained. CGA-mRNA, COLI-mRNA, COLIII-mRNA and ADAMTS-1-mRNA were analyzed by real-time PCR. The location and expression of CGA were assessed by immunohistochemistry(INH)with anti-CGA antibody. The collagen specific picrosirius red staining was applied on transversal myocardial slides and the collagen volume fraction (CVF) was calculated. The correlation between CGA and CVF was analyzed.</p><p><b>RESULTS</b>Cytoplasmic expression of CGA assessed by INH showed large amount of strong positive granules densely arranged in the epicardial and endocardial myocardiocytes in DCM specimen while there was only few sparse granules in the normal myocardium (P < 0.05). CVF was significantly higher in DCM myocardial specimen than that in normal specimen (P < 0.001). CGA-mRNA was significantly correlated with COLI-mRNA (r = 0.729), COLIII-mRNA (r = 0.95) and ADAMTS-1-mRNA (r = 0.665, all P < 0.05). Moreover, collagen deposition location was almost identical with the strong positive expression location of CGA.</p><p><b>CONCLUSION</b>We demonstrated for the first time that the deposition of CGA was related with the myocardial fibrosis in DCM heart, therefore, CGA might play an important role by influencing myocardial remodeling and fibrosis in DCM patients.</p>

Effect of astragaloside on myocardial fibrosis in chronic myocarditis / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To investigate the effect of astragaloside (Astr), one of the active components of the Chinese medical herb Astragulus membranaceus, on cardiac fibrosis in chronic myocarditis and its relevant mechanisms.</p><p><b>METHODS</b>Eighty mice were randomized into 3 groups, the control group (n=20), the model group (n=30) and the Astr group (n=30). Mice in the model group and the Astr group were monthly intraperitoneally inoculated with CVB3, but to the control group equal amount of culture fluid was given instead. Mice in the control and the model group were fed with drinking water while those in the Astr group with drinking water containing Astr-sodium carboxymethycellulose at a concentration of 300 mg/L. All the survived mice were sacrificed 3 months later. Heart tissue of mice was stained by picrosirius red for calculating collagen volume fraction (CVF) with an automatic image analysis system. Expressions of transforming growth factor beta1 (TGF-beta1), platelet derived growth factor (PDGF), matrix metalloproteinase 1 (MMP-1), tissue inhibitor of metalloproteinase 1 (TIMP-1), MMP-13 and MMP-14 in heart tissue were detected by Western blot analysis.</p><p><b>RESULTS</b>As compared with the model group, in the Astr group, the mortality and CVF were significantly lower (53.3% vs. 23.3%, chi2 = 4.23, P < 0.05), and (17.4 +/- 1.2% vs. 8.6 +/- 0.9%, chi2 = 5.38, P < 0.05), respectively. As compared with the control group, Western blot analysis showed that expression of TGF-beta1 was decreased, MMP-1 and TIMP-1 were down-regulated, while expressions of MMP-13 and MMP-14 were up-regulated after Astr treatment.</p><p><b>CONCLUSION</b>Astr could lower the mortality and alleviate the myocardial fibrosis of mice with chronic myocarditis. Its antifibrotic effect might be realized by way of inhibiting TGF-beta1 expression and up-regulating the expressions of MMP-13 and MMP-14 in the heart tissues.</p>

Upregulating the expression of angiogenesis-related genes by transplanting autologous mononuclear bone marrow cells into myocardial infarction scar and the periphery / 中华心血管病杂志

<p><b>OBJECTIVE</b>To detect the regulation of angiogenic genes involved in the processes of collateral development.</p><p><b>METHODS</b>Myocardial infarction (MI) scar was induced by cryoinjury in New Zealand rabbits. Four weeks after MI, 24 hours before cell transplantation, bone marrow was aspirated from the right thigh bone and mononuclear bone marrow cells (BMCs) were isolated by Ficoll density gradient centrifugation. Then the mononuclear BMCs (n = 8) or IMDM culture medium (n = 8) were transplanted into infarction scar and the periphery. Four weeks after mononuclear BMCs transplantation, DNA microarray analysis was performed to detect the regulation of angiogenesis-related genes in infarction scar and the periphery. And the differences of angiogenic genes expression were compared among several important growth factors by Western blot.</p><p><b>RESULTS</b>DNA microarray analysis showed the detail regulation of genes involved in the angiogenic processes. There were 15 genes upregulated over 3 times in the infarction scar. In addition, we also found more genes are involved in the process of angiogenesis in its periphery than in the infarction scar (40 genes vs. 15 genes). Western bolt analysis further demonstrated that mononuclear BMCs transplantation was capable of increasing the levels of VEGF, FGF and Angiopoietin-I expression in the infarction scar and its periphery, compared with the control group, P < 0.05.</p><p><b>CONCLUSION</b>These findings indicate that the natural angiogenic processes leading to collateral development are extremely complex, since many kinds of bone marrow-derived growth factors involved in the processes after mononuclear BMCs transplantation into infarction sites.</p>

Microarray analysis of extracellular matrix genes expression in myocardium of mouse with Coxsackie virus B3 myocarditis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Extracellular matrix (ECM) orchestrates cell behaviour including growth, death, apoptosis, adhesion, migration, and invasion by activating several signalling pathways. Certain components of ECM, such as integrins, may act as receptors or co-receptors of enterovirus. ECM-activated gene expressions in myocardium of viral heart disease including myocarditis and partial cardiomyopathy remain elusive. This study was to investigate the expression of ECM-activated genes in myocardium of mouse with viral myocarditis.</p><p><b>METHODS</b>BALB/c mice were infected with Coxsackie virus B3 (CVB3) to establish an animal model of myocarditis. Uninfected mice were also prepared and served as controls. Specific mRNA expression pattern in myocarditic mouse heart was analysed by an in-house cDNA microarray containing 8,192 genes. Overexpressed ECM genes were selected and subsequently confirmed by Northern blot analysis.</p><p><b>RESULTS</b>Nine ECM genes were isolated, from the array of 8,192 genes, as overexpressed genes in hearts of myocarditic mice in comparison with controls. Subsequent Northern blot analysis confirmed that four of the nine genes were highly expressed. Expression of these four genes, Fin15, ILk, Lamr1 and ADAMTS-1, has not been reported previously to be induced by Coxsackie virus.</p><p><b>CONCLUSION</b>CVB3-induced myocarditis is associated with gene expression profiles of certain ECM components.</p>