Effect of nitrite on endothelial function in isolated lung

Efficacy of terpenoids in attenuating pulmonary edema in acute lung injury: A meta-analysis of animal studies

Background: The clinical efficiency of terpenoids in treating human acute lung injury (ALI) is yet to be determined. The lipopolysaccharide-induced rat model of ALI is a well-established and widely used experimental model for studying terpenoids’ effects on ALI. Using a systematic review and meta-analysis, the therapeutic efficiency of terpenoid administration on the lung wet-to-dry weight ratio in rats was investigated.

Methods: Using the Cochrane Library, Embase, and PubMed databases, a comprehensive literature search for studies evaluating the therapeutic efficacy of terpenoids on ALI in rats was conducted. The lung wet-to-dry weight ratio was extracted as the main outcome. The quality of the included studies was assessed using the Systematic Review Center for Laboratory Animal Experimentation’s risk of bias tool.

Results: In total, 16 studies were included in this meta-analysis. In general, terpenoids significantly lowered the lung wet-to-dry weight ratio when compared with the control vehicle (p = 0.0002; standardized mean difference (SMD): −0.16; 95% confidence interval (CI): −0.24, −0.08). Subgroup analysis revealed that low dose (≤10 μmol/kg) (p < 0.0001; SMD: −0.68; 95% CI: −1.02, −0.34), intraperitoneal injection (p = 0.0002; SMD: −0.43; 95% CI: −0.66, −0.20), diterpenoid (p = 0.004; SMD: −0.13; 95% CI: −0.23, −0.04), and triterpenoid (p = 0.04; SMD: −0.28; 95% CI: −0.54, −0.01) significantly lowered the lung wet-to-dry weight ratio when compared with the control vehicle.

Conclusion: A low dose of diterpenoid and triterpenoid administered intraperitoneally is effective in alleviating ALI. This systematic review and meta-analysis provides a valuable mirror for clinical research aiming at the advancement of terpenoids for preventive and therapeutic use.

Systematic Review Registration: CRD42022326779

Higher urine nitric oxide is associated with improved outcomes in patients with acute lung injury

RATIONALE

Nitrogen oxide (NO) species are markers for oxidative stress that may be pathogenic in acute lung injury (ALI).

OBJECTIVES

We tested two hypotheses in patients with ALI: (1) higher levels of urine NO would be associated with worse clinical outcomes, and (2) ventilation with lower VT would reduce urine NO as a result of less stretch injury.

METHODS

Urine NO levels were measured by chemiluminescence in 566 patients enrolled in the National Heart Lung and Blood Institute Acute Respiratory Distress Syndrome Network trial of 6 ml/kg versus 12 ml/kg VT ventilation. The data were expressed corrected and uncorrected for urine creatinine (Cr).

RESULTS

Higher baseline levels of urine NO to Cr were associated with lower mortality (odds ratio, 0.43 per log(10) increase in the ratio), more ventilator-free days (mean increase, 1.9 d), and more organ-failure-free days (mean increase, 2.3 d) on multivariate analysis (p < 0.05 for all analyses). Similar results were obtained using urine NO alone. NO to Cr levels were higher on Day 3 in the 6 ml/kg than in the 12 ml/kg VT group (p = 0.04).

CONCLUSIONS

Contrary to our hypothesis, higher urine NO was associated with improved outcomes in ALI at baseline and after treatment with the 6 ml/kg VT strategy. Higher endogenous NO may reflect less severe lung injury and better preservation of the pulmonary and systemic endothelium or may serve a protective function in patients with ALI.