Early cardiac injury in acute respiratory distress syndrome: comparison of two experimental models

The clinical effectiveness of sivelestat in treating sepsis patients with both acute respiratory distress syndrome and septic cardiomyopathy

BACKGROUND

We aimed to assess the efficacy of the neutrophil elastase inhibitor, sivelestat, in the treatment of sepsis-induced acute respiratory distress syndrome (ARDS) and septic cardiomyopathy (SCM).

METHODS

Between January 2019 and December 2021, we conducted a randomized trial on patients who had been diagnosed with sepsis-induced acute respiratory distress syndrome (ARDS) and septic cardiomyopathy (SCM) at Wuhan Union Hospital. The patients were divided into two groups by random envelop method, the Sivelestat group and the Control group. We measured the serum concentrations of Interleukin (IL)-6, IL-8, Tumor necrosis factor-α (TNF-α), and High-mobility group box 1 (HMGB1) at five time points, which were the baseline, 12 h, 24 h, 48 h, and 72 h after admission to the ICU. We evaluated the cardiac function by sonography and the heart rate variability (HRV) with 24-hour Holter recording between the time of admission to the intensive care unit (ICU) and 72 h after Sivelestat treatment.

RESULTS

From January 2019 to December 2021, a total of 70 patients were included in this study. The levels of IL-6, IL-8, and TNF-α were significantly lower in the Sivelestat group at different time points (12 h, 24 h, 48 h, and 72 h). HMGB1 levels were significantly lower at 72 h after Sivelestat treatment (19.46 ± 2.63pg/mL vs. 21.20 ± 2.03pg/mL, P = 0.003). The stroke volume (SV), tricuspid annular plane systolic excursion (TAPSE), early to late diastolic transmitral flow velocity (E/A), early (e') and late (a') diastoles were significantly low in the Control group compared with the Sivelestat group. Tei index was high in the Control group compared with the Sivelestat group (0.60 ± 0.08 vs. 0.56 ± 0.07, P = 0.029). The result of HRV showed significant differences in standard deviation of normal-to-normal intervals (SDNN), low frequency (LF), and LF/HF (high frequency) between the two groups.

CONCLUSIONS

Sivelestat can significantly reduce the levels of serum inflammatory factors, improve cardiac function, and reduce heart rate variability in patients with Sepsis-induced ARDS and SCM.

Efficacy of surfactant therapy of ARDS induced by hydrochloric acid aspiration followed by ventilator-induced lung injury - an animal study

The development of acute respiratory distress syndrome (ARDS) is known to be independently attributable to aspiration-induced lung injury. Mechanical ventilation as a high pressure/volume support to maintain sufficient oxygenation of a patient could initiate ventilator-induced lung injury (VILI) and thus contribute to lung damage. Although these phenomena are rare in the clinic, they could serve as the severe experimental model of alveolar-capillary membrane deterioration. Lung collapse, diffuse inflammation, alveolar epithelial and endothelial damage, leakage of fluid into the alveoli, and subsequent inactivation of pulmonary surfactant, leading to respiratory failure. Therefore, exogenous surfactant could be considered as a therapy to restore lung function in experimental ARDS. This study aimed to investigate the effect of modified porcine surfactant in animal model of severe ARDS (P/F ratio </=13.3 kPa) induced by intratracheal instillation of hydrochloric acid (HCl, 3 ml/kg, pH 1.25) followed by VILI (V(T) 20 ml/kg). Adult rabbits were divided into three groups: untreated ARDS, model treated with a bolus of poractant alfa (Curosurf®, 2.5 ml/kg, 80 mg phospholipids/ml), and healthy ventilated animals (saline), which were oxygen-ventilated for an additional 4 h. The lung function parameters, histological appearance, degree of lung edema and levels of inflammatory and oxidative markers in plasma were evaluated. Whereas surfactant therapy with poractant alfa improved lung function, attenuated inflammation and lung edema, and partially regenerated significant changes in lung architecture compared to untreated controls. This study indicates a potential of exogenous surfactant preparation in the treatment of experimental ARDS.

Fundamentals of vaping-associated pulmonary injury leading to severe respiratory distress

Vaping of flavored liquids has been touted as safe alternative to traditional cigarette smoking with decreased health risks. The popularity of vaping has dramatically increased over the last decade, particularly among teenagers who incorporate vaping into their daily life as a social activity. Despite widespread and increasing adoption of vaping among young adults, there is little information on long-term consequences of vaping and potential health risks. This study demonstrates vaping-induced pulmonary injury using commercial JUUL pens with flavored vape juice using an inhalation exposure murine model. Profound pathological changes to upper airway, lung tissue architecture, and cellular structure are evident within 9 wk of exposure. Marked histologic changes include increased parenchyma tissue density, cellular infiltrates proximal to airway passages, alveolar rarefaction, increased collagen deposition, and bronchial thickening with elastin fiber disruption. Transcriptional reprogramming includes significant changes to gene families coding for xenobiotic response, glycerolipid metabolic processes, and oxidative stress. Cardiac systemic output is moderately but significantly impaired with pulmonary side ventricular chamber enlargement. This vaping-induced pulmonary injury model demonstrates mechanistic underpinnings of vaping-related pathologic injury.