Search

Background: The no-reflow (NR) phenomenon exists despite percutaneous coronary intervention (PCI), and is especially prevalent in diabetics. The causes(s) of NR are not fully elucidated, but may be associated with impaired residual platelet and inflammatory reactivity during dual-antiplatelet therapy., Objective: To assess the relationship between dual-antiplatelet therapy, NR and conventional biomarkers suggestive of platelet and inflammatory response in diabetics following ST-segment elevation myocardial infarction (STEMI) treated with PCI., Methods: Sixty diabetics with (n = 27) and without NR (n = 33) were prospectively enrolled. All patients were treated with clopidogrel and aspirin. Platelet and inflammatory biomarkers were assessed serially in the peripheral blood and right atrium before and after PCI and then at 24 h, 7 days and 30 days., Results: Arachidonic acid (AA)-induced platelet aggregation and the serum thromboxane B2 level before and after PCI (in the peripheral and right atrium blood) were significantly higher in the NR patients than in those with no NR. AA-induced aggregation >100 (AUC*min) before PCI predicted NR in diabetic patients with 96.2% sensitivity and 38.5% specificity (AUC 0.66; 95% CI 0.52-0.71; p = 0.029). There were no other correlations between NR and platelet reactivity (collagen, adenosine diphosphate, thrombin receptor agonist peptide-induced aggregation, vasodilator-stimulated phosphoprotein platelet reactivity index, soluble P-selectin, soluble CD40 ligand, platelet-derived growth factor AB and the level of platelet-monocyte aggregates) or between NR and inflammatory indices (i.e. high-sensitivity C-reactive protein, interleukin 6 and interleukin 10)., Conclusion: An inadequate response to aspirin, but not to clopidogrel, may be associated with the occurrence of the NR phenomenon in diabetics with STEMI who have been treated with primary PCI., (© 2015 S. Karger AG, Basel.)

The pulmonary surfactant is a complex mixture of lipids and proteins that is important for respiratory lung functions, which also provides the first line of innate immune defense. Pulmonary surfactant protein-A (SP-A) is a major surfactant component with immune functions with importance during Staphylococcus aureus infections that has been demonstrated in numerous studies. The current study showed that S. aureus can efficiently cleave the SP-A protein using its arsenal of proteolytic enzymes. This degradation appears to be mediated by cysteine proteases, in particular staphopain A (ScpA). The staphopain-mediated proteolysis of SP-A resulted in a decrease or complete abolishment of SP-A biological activity, including the promotion of S. aureus phagocytosis by neutrophils, aggregation of Gram-negative bacteria and bacterial cell adherence to epithelium. Significantly, ScpA has also efficiently degraded SP-A in complete bronchi-alveolar lavage fluid from human lungs. This indicates that staphopain activity in the lungs is resistant to protease inhibitors, thus suggesting that SP-A can be cleaved in vivo. Collectively, this study showed that the S. aureus protease ScpA is an important virulence factor that may impair innate immunity of the lungs., (Copyright © 2012 S. Karger AG, Basel.)