Early Plasma Matrix Metalloproteinase Profiles. A Novel Pathway in Pediatric Acute Respiratory Distress Syndrome

RATIONALE

MMPs (Matrix metalloproteinases) and their endogenous tissue inhibitors may contribute to lung injury through extracellular matrix degradation and modulation of inflammation and fibrosis.

OBJECTIVES

To test for an association between MMP pathway proteins and inflammation, endothelial dysfunction, and clinical outcomes.

METHODS

We measured MMPs in plasma collected on acute respiratory distress syndrome (ARDS) Day 1 from 235 children at five hospitals between 2008 and 2017. We used latent class analysis to identify patients with distinct MMP profiles and then associated those profiles with markers of inflammation (IL-1RA, -6, -8, -10, and -18; macrophage inflammatory protein-1α and -1β; tumor necrosis factor-α and -R2), endothelial injury (angiopoietin-2, von Willebrand factor, soluble thrombomodulin), impaired oxygenation (PaO2/FiO2 [P/F] ratio, oxygenation index), morbidity, and mortality.

MEASUREMENTS AND MAIN RESULTS

In geographically distinct derivation and validation cohorts, approximately one-third of patients demonstrated an MMP profile characterized by elevated MMP-1, -2, -3, -7, and -8 and tissue inhibitor of metalloproteinase-1 and -2; and depressed active and total MMP-9. This MMP profile was associated with multiple markers of inflammation, endothelial injury, and impaired oxygenation on Day 1 of ARDS, and conferred fourfold increased odds of mortality or severe morbidity independent of the P/F ratio and other confounders (95% confidence interval, 2.1-7.6; P < 0.001). Logistic regression using both the P/F ratio and MMP profiles was superior to the P/F ratio alone in prognosticating mortality or severe morbidity (area under the receiver operating characteristic curve, 0.75; 95% confidence interval, 0.68-0.82 vs. area under the receiver operating characteristic curve, 0.66; 95% confidence interval, 0.58-0.73; P = 0.009).

CONCLUSIONS

Pediatric patients with ARDS have specific plasma MMP profiles associated with inflammation, endothelial injury, morbidity, and mortality. MMPs may play a role in the pathobiology of children with ARDS.

Ciclopirox prevents peroxynitrite toxicity in astrocytes by maintaining their mitochondrial function: a novel mechanism for cytoprotection by ciclopirox

Previously we have reported that astrocytes deprived of glucose were highly vulnerable to peroxynitrite (Choi and Kim, J. Neurosci. Res. 54 (1998) 870; Neurosci. Lett. 256 (1988) 109; Ju et al., J. Neurochem. 74 (2000) 1989). Here we report that ciclopirox, which is clinically used as an anti-fungal agent, completely prevents the increased death in glucose-deprived astrocytes exposed to 3-morpholinosydnonimine (SIN-1, a peroxynitrite-releasing reagent). The increased vulnerability was in good correlation with the peroxynitrite-evoked decrease of mitochondrial transmembrane potential (MTP) in astrocytes. A simultaneous exposure to glucose deprivation and SIN-1 rapidly depolarized MTP and depleted ATP in astrocytes. Inclusion of ciclopirox initially increased the MTP, maintained it high, and blocked the ATP depletion in glucose-deprived SIN-1-treated astrocytes. However, ciclopirox did not prevent the depletion of reduced glutathione in glucose-deprived SIN-1-treated astrocytes. Consistently, ciclopirox did not scavenge various kinds of oxidants including peroxynitrite, nitric oxide, superoxide anion, hydrogen peroxide and hydroxyl radical. Ciclopirox has been experimentally used as a cell cycle G1/S phase transition blocker (Hoffman et al., Cytometry 12 (1991) 26). Flow cytometry analysis, however, showed that the cytoprotective effect of ciclopirox was not attributed to its inhibition of the cell cycle progression. The present results indicate that ciclopirox protects astrocytes from peroxynitrite cytotoxicity by attenuating peroxynitrite-induced mitochondrial dysfunction.