Point: Should paralytic agents be routinely used in severe ARDS? Yes

MMP3 in Severe COVID-19: A Biomarker or Therapeutic Target?

Identifying novel therapies is a critical need in the treatment of coronavirus disease-19 (COVID-19) and acute respiratory distress syndrome (ARDS). Stromelysin-1, also known as matrixmetalloproteinase 3 (MMP3), has been investigated as a diagnostic biomarker and a potential pharmacological target. Here, we discuss the recent findings of Gelzo et al. in the context of additional MMP3 investigations to delineate its exact role in diagnosis, prognostication, and phenotyping, in addition to its promising role as a therapeutic target in COVID-19-associated respiratory failure.

Cisatracurium attenuates LPS-induced modulation of MMP3 and junctional protein expression in human microvascular endothelial cells

Acute respiratory distress syndrome (ARDS) is a life-threatening form of acute lung injury (ALI) associated with hypoxemic lung damage and inflammation. Matrix metalloproteinase protein-3 (MMP3 or Stromelysin-1) is known to promote vascular injury in ALI/ARDS. Cisatracurium, a nicotinic neuromuscular blocker, is used in ARDS patients to decrease mechanical ventilator dyssynchrony, increase oxygenation, and improve mortality. However, the magnitude and the underlying mechanisms of these potential benefits of cisatracurium remains unclear. We investigated the effect of cisatracurium on lipopolysaccharide-induced MMP3 expression in human microvascular endothelial cells. In our results, cisatracurium treatment significantly decreased LPS-induced MMP3 expression and increased expression of cell junction proteins such as vascular endothelial cadherin (VE-cadherin) and claudin-5.

Double-blind, placebo-controlled pilot randomized trial of methylprednisolone infusion in pediatric acute respiratory distress syndrome

OBJECTIVE

Low-dose methylprednisolone therapy in adults with early acute respiratory distress syndrome reduces systemic inflammation, duration of mechanical ventilation, and ICU length of stay. We report a pilot randomized trial of glucocorticoid treatment in early pediatric acute respiratory distress syndrome.

DESIGN

Double-blind, placebo-controlled randomized clinical trial.

SETTING

Le Bonheur Children's Hospital, Memphis, TN.

PATIENTS

Children (0-18 yr) with acute respiratory distress syndrome undergoing mechanical ventilation.

INTERVENTIONS

Patients were randomly assigned to steroid or placebo groups within 72 hours of intubation. IV methylprednisolone administered as loading dose (2 mg/kg) and continuous infusions (1 mg/kg/d) on days 1-7 and then tapered over days 8-14. Both groups were ventilated according to the Acute Respiratory Distress Syndrome Network protocol modified for children. Daily surveillance was performed for adverse effects.

MEASUREMENTS AND MAIN RESULTS

Thirty-five patients were randomized to the steroid (n = 17, no death) and placebo groups (n = 18, two deaths). No differences occurred in length of mechanical ventilation, ICU stay, hospital stay, or mortality between the two groups. At baseline, higher plateau pressures (p = 0.006) and lower Pediatric Logistic Organ Dysfunction scores (p = 0.04) occurred in the steroid group; other characteristics were similar. Despite higher plateau pressures on days 1 (p = 0.006) and 2 (p = 0.025) due to poorer lung compliance in the steroid group, they had lower PaCO2 values on days 2 (p = 0.009) and 3 (p = 0.014), higher pH values on day 2 (p = 0.018), and higher PaO2/FIO2 ratios on days 8 (p = 0.047) and 9 (p = 0.002) compared with the placebo group. Fewer patients in the steroid group required treatment for postextubation stridor (p = 0.04) or supplemental oxygen at ICU transfer (p = 0.012). Steroid therapy was not associated with detectable adverse effects.

CONCLUSION

This study demonstrates the feasibility of administering low-dose glucocorticoid therapy and measuring clinically relevant outcomes in pediatric acute respiratory distress syndrome. Changes in oxygenation and/or ventilation are consistent with early acute respiratory distress syndrome pathophysiology and results of similar clinical trials in adults. We propose and design a larger randomized trial to define the role of glucocorticoid therapy in pediatric acute respiratory distress syndrome.