Interrogation of the infarcted and salvaged myocardium using multi-parametric mapping cardiovascular magnetic resonance in reperfused ST-segment elevation myocardial infarction patients

We used multi-parametric cardiovascular magnetic resonance (CMR) mapping to interrogate the myocardium following ST-segment elevation myocardial infarction (STEMI). Forty-eight STEMI patients underwent CMR at 4 ± 2 days. One matching short-axis slice of native T1 map, T2 map, late gadolinium enhancement (LGE), and automated extracellular volume fraction (ECV) maps per patient were analyzed. Manual regions-of-interest were drawn within the infarcted, the salvaged and the remote myocardium. A subgroup analysis was performed in those without MVO and with ≤75% transmural extent of infarct. For the whole cohort, T1, T2 and ECV in both the infarcted and the salvaged myocardium were significantly higher than in the remote myocardium. T1 and T2 could not differentiate between the salvaged and the infarcted myocardium, but ECV was significantly higher in the latter. In the subgroup analysis of 15 patients, similar findings were observed for T1 and T2. However, there was only a trend towards ECV_salvage being higher than ECV_remote. In the clinical setting, current native T1 and T2 methods with the specific voxel sizes at 1.5 T could not differentiate between the infarcted and salvaged myocardium, whereas ECV could differentiate between the two. ECV was also higher in the salvaged myocardium when compared to the remote myocardium.

Differential regulation of pro-inflammatory cytokine expression by MAP kinases in macrophages in response to intestinal parasite infection (MPF3P.816)

Blastocystis is a common enteric parasite that is associated with inflammatory bowel disease. However, the pathogenic status of Blastocystis remains unclear. In this study, we found that Blastocystis induced expression of pro-inflammatory cytokines including IL-1β, IL-6 and TNF-α in murine colon and macrophages. We showed that Blastocystis also induced the activation of the three major groups of MAP kinases (ERK, JNK, and p38) in macrophages. The use of MAPK-specific inhibitors in this study demonstrated differential regulation of pro-inflammatory cytokines in macrophages by MAPKs in response to Blastocystis. We found that ERK activation is important for the expression IL-6 and TNF-α at both mRNA and protein levels and the mRNA expression of IL-1β in response to Blastocystis stimulation. Inhibition of JNK significantly suppressed all three pro-inflammatory cytokines at both mRNA and protein levels. p38 inhibition only suppressed IL-6 secretion but not IL-1β and TNF-α. Furthermore, we found that serine proteases from Blastocystis are important for the activation of MAPKs and cytokine expression in macrophages. Our study demonstrated for the first time that Blastocystis could induce the expression of various pro-inflammatory cytokines via activation of MAP kinases, and infection with Blastocystis may contribute to the pathogenesis of inflammatory intestinal diseases through the activation of inflammatory pathways in host immune cells such as macrophages.