Lower Angiotensin I (A(1-10)) concentration was associated with ARDS survival (OR 0.36; 95% CI 0.18-0.72; p=0.004), while higher A(1-9) concentration also predicted survival.
Observational (n=39)
Do circulating renin angiotensin system (RAS) peptide levels predict survival in patients with ARDS?
Plasma levels of angiotensin I (A(1-10)) and A(1-9) and their ratio may serve as prognostic biomarkers for survival in ARDS patients.
Effect estimate: OR 0.36 (95% CI 0.18-0.72)
p-value: p=0.004
RATIONALE: We propose renin angiotensin system (RAS) peptides are critical in wound reparative processes such as in acute respiratory distress syndrome (ARDS). Their role in predicting clinical outcomes in ARDS has been unexplored; thus, we used a targeted metabolomics approach to investigate them as potential predictors of outcomes. METHODS: Thirty-nine ARDS patients were enrolled within 24 hours of ARDS diagnosis. Plasma RAS peptide levels were quantified at study entry and 24, 48 and 72 hours using a liquid chromatography-mass spectrometry based metabolomics assay. RAS peptide concentrations were compared between survivors and non-survivors, and were correlated with clinical and pulmonary measures. MEASUREMENTS AND MAIN RESULTS: Angiotensin I (Ang-I or A(1-10)) levels were significantly higher in non-survivors at study entry and 72 hours. ARDS survival was associated with lower A(1-10) concentration (OR 0.36, 95% CI 0.18-0.72, p = 0.004) but higher A(1-9) concentration (OR 2.24, 95% CI 1.15-4.39, p = 0.018), a biologically active metabolite of A(1-10) and an agonist of angiotensin II receptor type 2. Survivors had significantly higher median A(1-9)/A(1-10) and A(1-7)/A(1-10) ratios than the non-survivors (p = 0.001). Increased A(1-9)/A(1-10) ratio suggests that angiotensin converting enzyme II (ACE2) activity is higher in patients who survived their ARDS insult while an increase in A(1-7)/A(1-10) ratio suggests that ACE activity is also higher in survivors. CONCLUSION: A(1-10) accumulation and reduced A(1-9) concentration in the non-survivor group suggest that ACE2 activities may be reduced in patients succumbing to ARDS. Plasma levels of both A(1-10) and A(1-9) and their ratio may serve as useful biomarkers for prognosis in ARDS patients.
Reddy et al. (2019) conducted an observational in Acute Respiratory Distress Syndrome (ARDS) (n=39). Plasma RAS peptide levels vs. Survivors vs non-survivors was evaluated on ARDS survival (association with A(1-10) concentration) (OR 0.36, 95% CI 0.18-0.72, p=0.004). Lower Angiotensin I (A(1-10)) concentration was associated with ARDS survival (OR 0.36; 95% CI 0.18-0.72; p=0.004), while higher A(1-9) concentration also predicted survival.