Plasma Soluble Suppression of Tumorigenicity-2 Associates with Ventilator Liberation in Acute Hypoxemic Respiratory Failure

Serial laboratory biomarkers are associated with ICU outcomes in patients hospitalized with COVID-19

BACKGROUND

Clinical utility of routinely measured serial biomarkers in predicting escalation of inpatient care intensity and mortality among hospitalized patients with COVID-19 remains unknown.

METHODS

This retrospective cohort study included patients with COVID-19 who admitted to the Massachusetts General Hospital between March and June 2020 and January to March 2021. White blood cell (WBC) count, platelet count, C-reactive protein (CRP), and D-dimer values were measured on days 1, 3, and 7 of admission. Clinical outcomes include 30- and 60-day morality, ICU transfer, and overall survival (OS) over a follow-up period of 90 days. The association between serial biomarkers and outcomes were assessed using multivariable logistic regression and Cox proportional hazards models.

MEASUREMENTS AND MAIN RESULTS

Of the 456 patients hospitalized with COVID-19, 199 (43.6%) were ICU, 179 (39.3%) were medical floor, and 78 (17.1%) were initially admitted to the medical floor and then transferred to the ICU. In adjusted analyses, each unit increase in the slope of CRP was associated with a 42% higher odds of ICU transfer after controlling for the initial admission level (OR = 1.42, 95% CI: 1.25-1.65, P < 0.001). Including serial change in CRP levels from initial level on admission achieved the greatest predictive accuracy for ICU transfer (AUC = 0.72, 95% CI: 0.64-0.79).

CONCLUSIONS

Serial change in CRP levels from admission is associated with escalations of inpatient care intensity and mortality among hospitalized patients with COVID-19.

Predictive Value of GDF-15 and sST2 for Pulmonary Hypertension in Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Objective

To confirm whether growth differentiation factor-15 (GDF-15) and soluble suppression of tumorigenicity 2 (sST2) are indicators of pulmonary hypertension in acute exacerbation of chronic obstructive pulmonary disease (AECOPD-PH).

Methods

All patients admitted to the hospital with AECOPD between July 2020 and October 2021 were enrolled. The patients were then categorized into AECOPD and AECOPD-PH groups according to PH probability, and the differences in GDF-15 and sST2 serum levels in the AECOPD and AECOPD-PH groups were compared. Correlation analysis was carried out to explore the association between GDF-15 and sST2 serum levels and the length of hospital stay of patients with AECOPD-PH. Receiver operating characteristic curve analysis was used to assess the clinical significance of GDF-15 and sST2 in predicting patients with AECOPD-PH.

Results

Included in this study were 126 patients with AECOPD, including 69 with AECOPD and 57 with AECOPD-PH. The serum levels of GDF-15 and sST2 in the AECOPD-PH group were significantly higher than those in the AECOPD group (P < 0.05). There was no significant correlation between the length of hospital stay in AECOPD-PH patients and GDF-15 and sST2 serum levels (P > 0.05). The area under the curves of GDF-15, sST2, and GDF-15 + sST2 for predicting AECOPD-PH and AECOPD-PH patients with poor prognosis were >0.60 and 0.70, respectively. The optimal cutoff values of GDF-15 and sST2 for predicting AECOPD-PH were 1125.33 pg/mL and 80.68 ng/mL and 1309.72 pg/mL and 59.10 ng/mL for predicting AECOPD-PH patients with poor prognosis, respectively.

Conclusion

GDF-15 and sST2 levels may be useful in the prediction of AECOPD-PH.

Analytical performances of a new rapid assay of soluble ST2 for cardiac and inflammatory diseases and establishment of the reference intervals for children and adolescence in China

Background

sST2 has emerged as a potential disease biomarker of cardiac and inflammatory diseases in pediatrics. This study aimed to evaluate the performance of the new Pylon sST2 assay and establish the reference intervals of sST2 in children and adolescence in China.

Methods

The experiments on precision, linearity, effects of interferents and sample stability were carried out to evaluate the analytical performances. A total of 240 healthy participants, aged from 2 to 17 years were enrolled. The nonparametric method was used to calculate the age- and sex-specified reference intervals. sST2 levels were measured in children with different diseases to evaluate the assay's diagnostic performance.

Results

The repeatability and within-laboratory imprecision CVs of the assay were 6.0% and 7.6% at 19.5 ng/ml, and 3.1% and 5.9% at 289.8 ng/ml, respectively. The method showed linearity between 2.5 and 918.5 ng/ml. It was also noteworthy that the sST2 level was not affected in the presence of hemoglobin (2 mg/ml), triglyceride (30 mg/ml), bilirubin (0.3 mg/ml) and cholesterol (5 mg/ml). sST2 was found stable for 5 days at 4 °C in serum sample. The reference interval was determined as 2.1-21.0 ng/ml in general. No significant variation was observed by sex. However, sST2 increased constantly with age, especially in male. Increased sST2 was found in patients of systemic lupus erythematosus, sepsis, Crohn's diseases, respiratory failure and post cardiac surgery.

Conclusions

The Pylon sST2 assay showed good analytical performances. The reference intervals were established in children and adolescence and sST2 showed potential clinical values in several diseases in pediatrics.

Validating a Proteomic Signature of Severe COVID-19

COVID-19 is a heterogenous disease. Biomarker-based approaches may identify patients at risk for severe disease, who may be more likely to benefit from specific therapies. Our objective was to identify and validate a plasma protein signature for severe COVID-19.

DESIGN

Prospective observational cohort study.

SETTING

Two hospitals in the United States.

PATIENTS

One hundred sixty-seven hospitalized adults with COVID-19.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

We measured 713 plasma proteins in 167 hospitalized patients with COVID-19 using a high-throughput platform. We classified patients as nonsevere versus severe COVID-19, defined as the need for high-flow nasal cannula, mechanical ventilation, extracorporeal membrane oxygenation, or death, at study entry and in 7-day intervals thereafter. We compared proteins measured at baseline between these two groups by logistic regression adjusting for age, sex, symptom duration, and comorbidities. We used lead proteins from dysregulated pathways as inputs for elastic net logistic regression to identify a parsimonious signature of severe disease and validated this signature in an external COVID-19 dataset. We tested whether the association between corticosteroid use and mortality varied by protein signature. One hundred ninety-four proteins were associated with severe COVID-19 at the time of hospital admission. Pathway analysis identified multiple pathways associated with inflammatory response and tissue repair programs. Elastic net logistic regression yielded a 14-protein signature that discriminated 90-day mortality in an external cohort with an area under the receiver-operator characteristic curve of 0.92 (95% CI, 0.88-0.95). Classifying patients based on the predicted risk from the signature identified a heterogeneous response to treatment with corticosteroids (p = 0.006).

CONCLUSIONS

Inpatients with COVID-19 express heterogeneous patterns of plasma proteins. We propose a 14-protein signature of disease severity that may have value in developing precision medicine approaches for COVID-19 pneumonia.

Serum soluble suppression of tumorigenicity 2 as a novel inflammatory marker predicts the severity of acute pancreatitis

BACKGROUND

Acute pancreatitis (AP) is an inflammatory disease in which the regulatory pathway is complex and not well understood. Soluble suppression of tumorigenicity 2 (sST2) protein receptor functions as a decoy receptor for interleukin (IL)-33 to prevent IL-33/suppression of tumorigenicity 2L (ST2L)-pathway-mediated T helper (Th)2 immune responses.

AIM

To investigate the role of sST2 in AP.

METHODS

We assessed the association between sST2 and severity of AP in 123 patients enrolled in this study. The serum levels of sST2, C-reactive protein (CRP) and Th1- and Th2-related cytokines, including interferon (IFN)-γ, tumor necrosis factor (TNF)-α, IL-2, IL-4, IL-5 and IL-13, were measured by highly sensitive ELISA, and the severity of AP in patients was evaluated by the 2012 Atlanta Classification Criteria.

RESULTS

Serum sST2 levels were significantly increased in AP patients, and further, these levels were significantly elevated in severe AP (SAP) patients compared to moderately severe AP (MSAP) and mild AP (MAP) patients. Logistic regression showed sST2 was a predictor of SAP [odds ratio (OR): 1.003 (1.001–1.006), P = 0.000]. sST2 cutoff point was 1190 pg/mL, and sST2 above this cutoff was associated with SAP. sST2 was also a predictor of any organ failure and mortality during AP [OR: 1.006 (1.003–1.009), P = 0.000, OR: 1.002 (1.001–1.004), P = 0.012, respectively]. Additionally, the Th1-related cytokines IFN-γ and TNF-α in the SAP group were higher and the Th2-related cytokine IL-4 in the SAP group was significantly lower than those in MSAP and MAP groups.

CONCLUSION

sST2 may be used as a novel inflammatory marker in predicting AP severity and may regulate the function and differentiation of IL-33/ST2-mediated Th1 and Th2 Lymphocytes in AP homeostasis.

Plasma 1,3-β-d-glucan levels predict adverse clinical outcomes in critical illness

BACKGROUNDThe fungal cell wall constituent 1,3-β-d-glucan (BDG) is a pathogen-associated molecular pattern that can stimulate innate immunity. We hypothesized that BDG from colonizing fungi in critically ill patients may translocate into the systemic circulation and be associated with host inflammation and outcomes.METHODSWe enrolled 453 mechanically ventilated patients with acute respiratory failure (ARF) without invasive fungal infection and measured BDG, innate immunity, and epithelial permeability biomarkers in serially collected plasma samples.RESULTSCompared with healthy controls, patients with ARF had significantly higher BDG levels (median [IQR], 26 pg/mL [15-49 pg/mL], P < 0.001), whereas patients with ARF with high BDG levels (≥40 pg/mL, 31%) had higher odds for assignment to the prognostically adverse hyperinflammatory subphenotype (OR [CI], 2.88 [1.83-4.54], P < 0.001). Baseline BDG levels were predictive of fewer ventilator-free days and worse 30-day survival (adjusted P < 0.05). Integrative analyses of fungal colonization and epithelial barrier disruption suggested that BDG may translocate from either the lung or gut compartment. We validated the associations between plasma BDG and host inflammatory responses in 97 hospitalized patients with COVID-19.CONCLUSIONBDG measurements offered prognostic information in critically ill patients without fungal infections. Further research in the mechanisms of translocation and innate immunity recognition and stimulation may offer new therapeutic opportunities in critical illness.FUNDINGUniversity of Pittsburgh Clinical and Translational Science Institute, COVID-19 Pilot Award and NIH grants (K23 HL139987, U01 HL098962, P01 HL114453, R01 HL097376, K24 HL123342, U01 HL137159, R01 LM012087, K08HK144820, F32 HL142172, K23 GM122069).

Soluble Suppression of Tumorigenicity-2 Associates With Ventilator Dependence in Coronavirus Disease 2019 Respiratory Failure

Supplemental Digital Content is available in the text.

OBJECTIVES:

We hypothesize that elevated soluble suppression of tumorigenicity-2 concentrations, a marker of pulmonary epithelial injury, reflect ongoing lung injury in acute hypoxemic respiratory failure due to coronavirus disease 2019 and associate with continued ventilator dependence.

DESIGN:

We associated serial plasma soluble suppression of tumorigenicity-2 levels and markers of systemic inflammation including d-dimer, C-reactive protein, and erythrocyte sedimentation rate with 30-day mortality and ventilator dependence.

SETTING:

Adult medical ICUs and general medicine wards at an academic teaching hospital in Boston, MA.

PATIENTS:

Adult patients with severe acute respiratory syndrome coronavirus 2 infection and acute hypoxemic respiratory failure admitted to the ICU (n = 72) and non-ICU patients managed with supplemental oxygen (n = 77).

INTERVENTIONS:

Observational study from April 25 to June 25, 2020.

MEASUREMENTS AND MAIN RESULTS:

ICU patients had a higher baseline body mass index and median soluble suppression of tumorigenicity-2, d-dimer, and C-reactive protein concentrations compared with non-ICU patients. Among ICU patients, elevated baseline modified Sequential Organ Failure Assessment score and log (soluble suppression of tumorigenicity-2) were associated with 30-day mortality, whereas initial Pao₂/Fio₂ and markers of systemic inflammation were similar between groups. Only log (soluble suppression of tumorigenicity-2) associated with ventilator dependence over time, with the last measured log (soluble suppression of tumorigenicity-2) concentration obtained on ICU day 11.5 (interquartile range [7–17]) higher in patients who required reintubation or tracheostomy placement compared with patients who were successfully extubated (2.10 [1.89–2.26] vs 1.87 ng/mL [1.72–2.13 ng/mL]; p = 0.03). Last measured systemic inflammatory markers, modified Sequential Organ Failure Assessment score, and Pao₂/Fio₂ were not different between patients who were successfully extubated compared with those with continued ventilator dependence.

CONCLUSIONS:

Plasma soluble suppression of tumorigenicity-2 is a biomarker readily measured in blood that can provide dynamic information about the degree of a patient’s lung injury and real-time assessment of the likelihood of extubation success. Measures of systemic inflammation, illness severity, and oxygenation did not associate with ventilator outcomes.