[Predictive value of D-dimer for deep venous thrombosis of lower extremity in adult burn patients].

Objective: To investigate the predictive value of D-dimer for deep venous thrombosis (DVT) of lower extremity in adult burn patients. Methods: A retrospective case series study was conducted. The clinical data of 3 861 adult burn patients who met the inclusion criteria and were admitted to the Department of Burns of Zhengzhou First People's Hospital from January 1, 2015 to December 31, 2019 were collected. The patients were divided into DVT group (n=77) and non-DVT group (n=3 784) according to whether DVT of lower extremity occurred during hospitalization or not. Data of patients in the two groups were collected and compared, including the gender, age, total burn area, D-dimer level, with lower limb burn and inhalation injury or not on admission, with sepsis/septic shock, femoral vein indwelling central venous catheter (CVC), history of surgery, and infusion of concentrated red blood cells or not during hospitalization. Data were statistically analyzed with independent sample t test, Mann-Whitney U test, and chi-square test. The indicators with statistically significant differences between the two groups were analyzed with multivariate logistic regression analysis to screen the independent risk factors for DVT of lower extremity in 3 861 adult burn patients. The receiver operating characteristic (ROC) curve of the independent risk factors predicting DVT of lower extremity in 3 861 adult burn patients were drawn, and the area under the curve (AUC), the optimal threshold value, and the sensitivity and specificity under the optimal threshold value were calculated. The quality of the AUC was compared by Delong test, and the sensitivity and specificity under the optimal threshold value were compared using chi-square test. Results: There were no statistically significant differences in gender, occurrence of sepsis/septic shock or history of surgery during hospitalization between patients in the two groups (P>0.05), while there were statistically significant differences in age, total burn area, D-dimer level, lower limb burn and inhalation injury on admission, and femoral vein indwelling CVC and infusion of concentrated red blood cells during hospitalization between patients in the two groups (t=-8.17, with Z values of -5.04 and -10.83, respectively, χ2 values of 21.83, 5.37, 7.75, and 4.52, respectively, P<0.05 or P<0.01). Multivariate logistic regression analysis showed that age, total burn area, and D-dimer level were the independent risk factors for DVT of lower extremity in 3 861 adult burn patients (with odds ratios of 1.05, 1.02, and 1.14, respectively, 95% confidence intervals of 1.04-1.06, 1.00-1.03, and 1.10-1.20, respectively, P<0.05 or P<0.01). The AUCs of ROC of age, total burn area, and D-dimer level for predicting DVT of lower extremity in 3 861 adult burn patients were 0.74, 0.67, and 0.86, respectively (with 95% confidence intervals of 0.68-0.80, 0.60-0.74, and 0.83-0.89, respectively, P values<0.01), the optimal threshold values were 50.5 years old, 10.5% total body surface area, and 1.845 mg/L, respectively, the sensitivity under the optimal threshold values were 71.4%, 70.1%, and 87.0%, respectively, and the specificity under the optimal threshold values were 66.8%, 67.2%, and 72.9%, respectively. The AUC quality and sensitivity and specificity under the optimal threshold value of D-dimer level were significantly better than those of age (z=3.29, with χ2 values of 284.91 and 34.25, respectively, P<0.01) and total burn area (z=4.98, with χ2 values of 326.79 and 29.88, respectively, P<0.01), while the AUC quality and sensitivity and specificity under the optimal threshold values were similar between age and total burn area (P>0.05). Conclusions: D-dimer level is an independent risk factor for DVT of lower extremity in adult burn patients, its AUC quality and sensitivity and specificity under the optimal threshold value are better than those of age and total burn area, and it has good predictive value for DVT of lower extremity in adult burn patients.

Silymarin/curcumin loaded albumin nanoparticles coated by chitosan as muco-inhalable delivery system observing anti-inflammatory and anti COVID-19 characterizations in oleic acid triggered lung injury and in vitro COVID-19 experiment.

Respiratory infected by COVID-19 represents a major global health problem at moment even after recovery from virus corona. Since, the lung lesions for infected patients are still sufferings from acute respiratory distress syndrome including alveolar septal edema, pneumonia, hyperplasia, and hyaline membranes Therefore, there is an urgent need to identify additional candidates having ability to overcome inflammatory process and can enhance efficacy in the treatment of COVID-19. The polypenolic extracts were integrated into moeties of bovine serum albumin (BSA) and then were coated by chitosan as a mucoadhesion polymer. The results of interleukin-6, and c-reactive protein showed significant reduction in group treated by Encap. SIL + CUR (64 ± 0.8 Pg/µL & 6 ± 0.5 µg/µL) compared to group treated by Cham. + CUR (102 ± 0.8 Pg/µL & 7 ± 0.5 µg/µL) respectively and free capsules (with no any drug inside) (148 ± 0.6 Pg/µL & 10 ± 0.6 µg/µL) respectively. Histopathology profile was improved completely. Additionally, encapsulating silymarin showed anti-viral activity in vitro COVID-19 experiment. It can be summarized that muco-inhalable delivery system (MIDS) loaded by silymarin can be used to overcome inflammation induced by oleic acid and to overcome COVID-19.

Plasma S-Adenosylmethionine Is Associated with Lung Injury in COVID-19.

OBJECTIVE: S-Adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) are indicators of global transmethylation and may play an important role as markers of severity of COVID-19. METHODS: The levels of plasma SAM and SAH were determined in patients admitted with COVID-19 (n = 56, mean age = 61). Lung injury was identified by computed tomography (CT) in accordance with the CT0-4 classification. RESULTS: SAM was found to be a potential marker of lung damage risk in COVID-19 patients (SAM > 80 nM; CT3,4 vs. CT 0-2: relative ratio (RR) was 3.0; p = 0.0029). SAM/SAH > 6.0 was also found to be a marker of lung injury (CT2-4 vs. CT0,1: RR = 3.47, p = 0.0004). There was a negative association between SAM and glutathione level (ρ = -0.343, p = 0.011). Interleukin-6 (IL-6) levels were associated with SAM (ρ = 0.44, p = 0.01) and SAH (ρ = 0.534, p = 0.001) levels. CONCLUSIONS: A high SAM level and high methylation index are associated with the risk of lung injury in patients with COVID-19. The association of SAM with IL-6 and glutathione indicates an important role of transmethylation in the development of cytokine imbalance and oxidative stress in patients with COVID-19.

Serum Krebs von den Lungen-6 for Predicting the Severity of COVID-19 Lung Injury: A Systematic Review and Meta-Analysis.

Background: Lung injury is common in coronavirus disease 2019 (COVID-19) patients. The severity of lung injury appears to be reflected in serum Krebs von den Lungen-6 (KL-6), a glycoprotein expressed on type II alveolar epithelium. This study aims to assess the role of serum KL-6 in reflecting the severity of lung injury in COVID-19 patients. Methods: A systematic search was conducted in Scopus, PubMed, Wiley Online Library, and ProQuest. Articles were screened based on several eligibility criteria and assessed for study quality using Newcastle-Ottawa Scale. Results: This systematic review included four studies involving a total of 151 adult COVID-19 patients. Pooled analysis revealed that serum KL-6 was significantly higher in severe patients (SMD = 1.16; 95% CI = 0.69­1.63) with moderately high pooled sensitivity (79%; 95% CI = 61­91%) and specificity (86%; 95% CI = 72­95%). Conclusion: High serum KL-6 may depict more severe lung injury in COVID-19 patients with moderately high sensitivity and specificity.

Dexamethasone may improve severe COVID-19 via ameliorating endothelial injury and inflammation: A preliminary pilot study.

Dexamethasone provides benefits in patients with coronavirus disease 2019 (COVID-19), although data regarding immunological profiles and viral clearance are limited. This study aimed to evaluate for differences in biomarkers among patients with severe COVID-19 who did and did not receive dexamethasone. We measured plasma biomarkers of lung epithelial/endothelial injury and inflammation in 31 patients with severe COVID-19 and in 13 controls. Changes in biomarkers and clinical parameters were compared during the 7-day period among COVID-19 patients, and also according to dexamethasone use. Thirty-two patients with severe COVID-19 who received mechanical ventilation (n = 6), high-flow nasal cannula (n = 11), and supplemental oxygen (n = 15) were analyzed. Relative to controls, patients with severe COVID-19 had significantly higher concentrations of biomarkers related to glycocalyx shedding (endocan and syndecan-1), endothelial injury (von Willebrand factor), and inflammation (soluble receptor for advanced glycation end-products [sRAGE] and interleukin-6). The 7-day decreases in biomarkers of endothelial injury (angiopoietin-2 [Ang-2] and intercellular adhesion molecule-1 [ICAM-1]) and sRAGE, but not in the biomarker of lung epithelial injury (surfactant protein D), were correlated with decreases in C-reactive protein and radiologic score at day 7. Twenty patients (63%) received dexamethasone, and the dexamethasone and non-dexamethasone groups differed in terms of disease severity. However, dexamethasone was associated marginally with increased SpO2/FiO2 and significantly with decreases in C-reactive protein and radiologic score after adjusting for baseline imbalances. Furthermore, the dexamethasone group exhibited a significant decrease in the concentrations of Ang-2, ICAM-1, soluble form of the Tie2 receptor (a biomarker of glycocalyx shedding), and sRAGE. Both groups exhibited a clinically insignificant increase in the cycle threshold value. Severe COVID-19 may be characterized by more severe endothelial injury and inflammation, and less severe lung epithelial injury. There is a possibility that dexamethasone improved severe COVID-19 and related endothelial injury without delaying viral clearance.

PEDF, a pleiotropic WTC-LI biomarker: Machine learning biomarker identification and validation.

Biomarkers predict World Trade Center-Lung Injury (WTC-LI); however, there remains unaddressed multicollinearity in our serum cytokines, chemokines, and high-throughput platform datasets used to phenotype WTC-disease. To address this concern, we used automated, machine-learning, high-dimensional data pruning, and validated identified biomarkers. The parent cohort consisted of male, never-smoking firefighters with WTC-LI (FEV1, %Pred< lower limit of normal (LLN); n = 100) and controls (n = 127) and had their biomarkers assessed. Cases and controls (n = 15/group) underwent untargeted metabolomics, then feature selection performed on metabolites, cytokines, chemokines, and clinical data. Cytokines, chemokines, and clinical biomarkers were validated in the non-overlapping parent-cohort via binary logistic regression with 5-fold cross validation. Random forests of metabolites (n = 580), clinical biomarkers (n = 5), and previously assayed cytokines, chemokines (n = 106) identified that the top 5% of biomarkers important to class separation included pigment epithelium-derived factor (PEDF), macrophage derived chemokine (MDC), systolic blood pressure, macrophage inflammatory protein-4 (MIP-4), growth-regulated oncogene protein (GRO), monocyte chemoattractant protein-1 (MCP-1), apolipoprotein-AII (Apo-AII), cell membrane metabolites (sphingolipids, phospholipids), and branched-chain amino acids. Validated models via confounder-adjusted (age on 9/11, BMI, exposure, and pre-9/11 FEV1, %Pred) binary logistic regression had AUCROC [0.90(0.84-0.96)]. Decreased PEDF and MIP-4, and increased Apo-AII were associated with increased odds of WTC-LI. Increased GRO, MCP-1, and simultaneously decreased MDC were associated with decreased odds of WTC-LI. In conclusion, automated data pruning identified novel WTC-LI biomarkers; performance was validated in an independent cohort. One biomarker-PEDF, an antiangiogenic agent-is a novel, predictive biomarker of particulate-matter-related lung disease. Other biomarkers-GRO, MCP-1, MDC, MIP-4-reveal immune cell involvement in WTC-LI pathogenesis. Findings of our automated biomarker identification warrant further investigation into these potential pharmacotherapy targets.

Neuron-specific enolase serum levels in COVID-19 are related to the severity of lung injury.

The multifunctional role of neuron-specific enolase (NSE) in lung diseases is well established. As the lungs are greatly affected in COVID-19, we evaluated serum NSE levels in COVID-19 patients with and without dyspnea. In this study, we evaluated both SARS-CoV-2-infected and uninfected patients aged >18 years who were referred to hospitals in Catanzaro, Italy from March 30 to July 30, 2020. Epidemiological, clinical, and radiological characteristics, treatment, and outcome data were recorded and reviewed by a trained team of physicians. In total, 323 patients (178 men, 55.1% and 145 women, 44.9%) were enrolled; of these, 128 were COVID-19 patients (39.6%) and 195 were control patients (60.4%). Westergren's method was used to determine erythroid sedimentation rate. A chemiluminescence assay was used for measurement of interleukin-6, procalcitonin, C-reactive protein, and NSE. We detected significantly higher NSE values (P<0.05) in COVID-19 patients than in controls. Interestingly, within the COVID-19 group, we also observed a further significant increase in dyspnea (Dyspnea Scale and Exercise score: 8.2 ± 0.8; scores ranging from 0 to 10, with higher numbers indicating very severe shortness of breath). These data provide the background for further investigations into the potential role of NSE as a clinical marker of COVID-19 progression.

Calcitriol Attenuates HRV-Induced Respiratory Injury through the AMPK-mTOR-ER Stress Signaling Pathway.

Human rhinovirus (HRV) infection is one of the main causes of respiratory injury. Recently, calcitriol has been reported to have protective effect against respiratory infections. In this paper, we aimed to explore the effects and mechanisms of calcitriol on HRV-induced respiratory infection. Participants including pediatric patients diagnosed with HRV-induced respiratory infection (n = 50) and paired healthy controls (n = 40) were recruited at the Weifang People's Hospital between May 2019 and May 2020. The serum 25(OH)D3 level was measured in participants using ELISA kit. The HRV-induced respiratory infection model in human nasal mucosal epithelial cells (hNECs) was adapted, in vitro. HRV infection was measured by real-time PCR analysis of HRV expression. After HRV infection and treatment with calcitriol, the changes of cell viability were detected by MTT assay, the expression of ER stress-induced apoptosis and AMPK-mTOR related proteins by western blot, and the cell apoptosis by flow cytometry assay. In order to confirm whether AMPK-mTOR signal pathway was involved in the ER stress-induced apoptosis of hNECs, cells were pretreated with compound C which was a AMPK inhibitor. The 25-(OH)D3 concentration in serum collected in HRV-infected children was lower than that in controls. In vitro experiments showed that HRV infection decreased cell viability, and this effect was reversed when treated with calcitriol. Additionally, HRV increased levels of apoptosis and ER stress markers (including cleaved-caspase3, Bax, CHOP, nATF6, and BiP), while calcitriol significantly reversed these effects. Furthermore, calcitriol played a protective role by increasing p-AMPK and decreasing p-mTOR level. However, the protective effects of calcitriol could be abolished by compound C. Calcitriol protected HRV-infected hNECs by inhibiting the ER stress-induced apoptosis through the AMPK-mTOR signaling pathway. These protective effects of calcitriol against HRV-induced respiratory infection may provide an experimental basis for the clinical application.

Pulmonary and vascular effects of acute ozone exposure in diabetic rats fed an atherogenic diet.

Air pollutants may increase risk for cardiopulmonary disease, particularly in susceptible populations with metabolic stressors such as diabetes and unhealthy diet. We investigated effects of inhaled ozone exposure and high-cholesterol diet (HCD) in healthy Wistar and Wistar-derived Goto-Kakizaki (GK) rats, a non-obese model of type 2 diabetes. Male rats (4-week old) were fed normal diet (ND) or HCD for 12 weeks and then exposed to filtered air or 1.0 ppm ozone (6 h/day) for 1 or 2 days. We examined pulmonary, vascular, hematology, and inflammatory responses after each exposure plus an 18-h recovery period. In both strains, ozone induced acute bronchiolar epithelial necrosis and inflammation on histopathology and pulmonary protein leakage and neutrophilia; the protein leakage was more rapid and persistent in GK compared to Wistar rats. Ozone also decreased lymphocytes after day 1 in both strains consuming ND (~50%), while HCD increased circulating leukocytes. Ozone increased plasma thrombin/antithrombin complexes and platelet disaggregation in Wistar rats on HCD and exacerbated diet effects on serum IFN-γ, IL-6, KC-GRO, IL-13, and TNF-α, which were higher with HCD (Wistar>GK). Ex vivo aortic contractility to phenylephrine was lower in GK versus Wistar rats at baseline(~30%); ozone enhanced this effect in Wistar rats on ND. GK rats on HCD had higher aortic e-NOS and tPA expression compared to Wistar rats. Ozone increased e-NOS in GK rats on ND (~3-fold) and Wistar rats on HCD (~2-fold). These findings demonstrate ways in which underlying diabetes and HCD may exacerbate pulmonary, systemic, and vascular effects of inhaled pollutants.

Markers of endothelial and epithelial pulmonary injury in mechanically ventilated COVID-19 ICU patients.

BACKGROUND: Biomarkers can be used to detect the presence of endothelial and/or alveolar epithelial injuries in case of ARDS. Angiopoietin-2 (Ang-2), soluble intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion protein-1 (VCAM-1), P-selectin and E-selectin are biomarkers of endothelial injury, whereas the receptor for advanced glycation end-products (RAGE) reflects alveolar epithelial injury. The aims of this study were to evaluate whether the plasma concentration of the above-mentioned biomarkers was different 1) in survivors and non-survivors of COVID-19-related ARDS and 2) in COVID-19-related and classical ARDS. METHODS: This prospective study was performed in two COVID-19-dedicated Intensive Care Units (ICU) and one non-COVID-19 ICU at Ferrara University Hospital. A cohort of 31 mechanically ventilated patients with COVID-19 ARDS and a cohort of 11 patients with classical ARDS were enrolled. Ang-2, ICAM-1, VCAM-1, P-selectin, E-selectin and RAGE were determined with a bead-based multiplex immunoassay at three time points: inclusion in the study (T1), after 7 ± 2 days (T2) and 14 ± 2 days (T3). The primary outcome was to evaluate the plasma trend of the biomarker levels in survivors and non-survivors. The secondary outcome was to evaluate the differences in respiratory mechanics variables and gas exchanges between survivors and non-survivors. Furthermore, we compared the plasma levels of the biomarkers at T1 in patients with COVID-19-related ARDS and classical ARDS. RESULTS: In COVID-19-related ARDS, the plasma levels of Ang-2 and ICAM-1 at T1 were statistically higher in non-survivors than survivors, (p = 0.04 and p = 0.03, respectively), whereas those of P-selectin, E-selectin and RAGE did not differ. Ang-2 and ICAM-1 at T1 were predictors of mortality (AUROC 0.650 and 0.717, respectively). At T1, RAGE and P-selectin levels were higher in classical ARDS than in COVID-19-related ARDS. Ang-2, ICAM-1 and E-selectin were lower in classical ARDS than in COVID-19-related ARDS (all p < 0.001). CONCLUSIONS: COVID-19 ARDS is characterized by an early pulmonary endothelial injury, as detected by Ang-2 and ICAM-1. COVID-19 ARDS and classical ARDS exhibited a different expression of biomarkers, suggesting different pathological pathways. Trial registration NCT04343053 , Date of registration: April 13, 2020.

Prognostic roles of KL-6 in disease severity and lung injury in COVID-19 patients: A longitudinal retrospective analysis.

To investigate the dynamic changes of Krebs von den Lungen-6 (KL-6) among patients with coronavirus disease 2019 (COVID-19) and the role of KL-6 as a noninvasive biomarker for predicting long-term lung injury, the clinical information and laboratory tests of 166 COVID-19 patients were collected, and a correlation analysis between KL-6 and other parameters was conducted. There were 17 (10.2%, 17/166) severe/critical and 149 (89.8%, 149/166) mild COVID-19 patients in our cohort. Serum KL-6 was significantly higher in severe/critical COVID-19 patients than in mild patients (median 898.0 vs. 451.2 U/ml, p < .001). KL-6 was next confirmed to be a sensitive and specific biomarker for distinguishing mild and severe/critical patients and correlate to computed tomography lung lesions areas. Serum KL-6 concentration during the follow-up period (>100 days postonset) was well correlated to those concentrations within 10 days postonset (Pearson r = .867, p < .001), indicating the prognostic value of KL-6 levels in predicting lung injury after discharge. Finally, elevated KL-6 was found to be significantly correlated to coagulation disorders, and T cells subsets dysfunctions. In summary, serum KL-6 is a biomarker for assessing COVID-19 severity and predicting the prognosis of lung injury of discharged patients.

Longitudinal clinical and radiographic evaluation reveals interleukin-6 as an indicator of persistent pulmonary injury in COVID-19.

Rationale: Previous studies of coronavirus disease 2019 (COVID-19) were mainly focused on cross-sectional analysis. In this study, we sought to evaluate the dynamic changes of immunological and radiographic features, and the association with the outcome of pulmonary lesions in COVID-19 patients. Methods: Peripheral blood samples and radiographic data were collected longitudinally for up to 8 weeks from 158 laboratory-confirmed COVID-19 patients. The chest computed tomography (CT) scans were scored based on a semi-quantification assessment according to the extent of pulmonary abnormalities; the temporal change of the immunological and radiographic features was analyzed. Results: Compared with mild and moderate patients, severe patients had significantly decreased counts of lymphocytes, CD4+ T cells, CD8+ T cells, and CD19+ B cells but dramatically elevated counts of neutrophils and levels of interleukin (IL)-6. Sequential monitoring showed a sustained increase in lymphocytes counts and significantly decreased levels of IL-6 in severe patients during the disease course. Notably, patients with persistent pulmonary lesions (CT score ≥ 5 in week 8) showed high levels of IL-6 during the follow-up period, compared with those with recovery lesions (CT score < 5 in week 8). More importantly, the peak expression of IL-6 prior to the aggravated lung injury was mainly found in patients with persistent lesions, and multivariate analysis showed that IL-6 level upon admission was an independent factor associated with the persistent pulmonary injury. Conclusion: Prolonged elevation of IL-6 is associated with persistent pulmonary lesions in COVID-19 patients. Sequential monitoring and timely intervention of IL-6 may favor the clinical management of COVID-19.

Co-administration of Luteolin mitigated toxicity in rats' lungs associated with doxorubicin treatment.

Doxorubicin (DOX), is a drug against lung malignancies with undesirable side effect including oxidative, inflammatory and apoptotic effects. Luteolin (LUT), present in fruits and vegetables is pharmacologically active against oxido-inflammatory and apoptotic responses. The present study examined the effect of LUT on DOX-induced lungs and blood dysfunction in Wistars rat (sex: male; 10 weeks old, 160 ± 5 g). Randomly grouped (n = 10) rats were treated as follows: control, LUT alone (100 mg/kg; per os), DOX (2 mg/kg; i. p), and co-treated rats with LUT (50 or 100 mg/kg) and DOX for two consecutive weeks. DOX alone adversely altered the final body and relative organ weights, red and white blood cell and platelet counts. DOX significantly (p > 0.05) reduced lungs antioxidant capacity, and anti-inflammatory cytokines; increased biomarkers of oxidative stress, caspase-3 activity, and pro-inflammatory cytokine. Morphological damages accompanied these biochemical alterations in the lung of experimental rats. Co-treatment with LUT, dose-dependently reversed DOX-mediated changes in rats' survival, toxic responses, and diminished oxidative stress in rat's lungs. Furthermore, co-treatment with LUT resulted in the reduction of pro-inflammatory cytokines and apoptotic biomarkers, increased red and white blood cell, platelet counts and abated pathological injuries in rat lungs treated with DOX alone. In essence, our findings indicate that LUT dose-dependently mitigated DOX-induced toxicities in the lungs and haematopoietic systems. Supplementation of patients on DOX-chemotherapy with phytochemicals exhibiting antioxidant activities, specifically LUT, could circumvent the onset of unintended toxic responses in the lungs and haematopoietic system exposed to DOX.

Lung injury induced by pyrrolizidine alkaloids depends on metabolism by hepatic cytochrome P450s and blood transport of reactive metabolites.

Pyrrolizidine alkaloids (PAs) are common phytotoxins with both hepatotoxicity and pneumotoxicity. Hepatic cytochrome P450 enzymes are known to bioactivate PAs into reactive metabolites, which can interact with proteins to form pyrrole-protein adducts and cause intrahepatic cytotoxicity. However, the metabolic and initiation biochemical mechanisms underlying PA-induced pneumotoxicity remain unclear. To investigate the in vivo metabolism basis for PA-induced lung injury, this study used mice with conditional deletion of the cytochrome P450 reductase (Cpr) gene and resultant tissue-selective ablation of microsomal P450 enzyme activities. After oral exposure to monocrotaline (MCT), a pneumotoxic PA widely used to establish animal lung injury models, liver-specific Cpr-null (LCN) mice, but not extrahepatic Cpr-low (xh-CL) mice, had significantly lower level of pyrrole-protein adducts in the serum, liver and lungs compared with wild-type (WT) mice. While MCT-exposed LCN mice had significantly higher blood concentration of intact MCT, compared to MCT-exposed WT or xh-CL mice. Consistent with the MCT in vivo bioactivation data, MCT-induced lung injury, represented by vasculature damage, in WT and xh-CL mice but not LCN mice. Furthermore, reactive metabolites of MCT were confirmed to exist in the blood efflux from the hepatic veins of MCT-exposed rats. Our results provide the first mode-of-action evidence that hepatic P450s are essential for the bioactivation of MCT, and blood circulating reactive metabolites of MCT to the lung causes pneumotoxicity. Collectively, this study presents the scientific basis for the application of MCT in animal lung injury models, and more importantly, warrants public awareness and further investigations of lung diseases associated with exposure to not only MCT but also different PAs.

Noninvasive SpO2/FiO2 ratio as surrogate for PaO2/FiO2 ratio during simulated prolonged field care and ground and high-altitude evacuation.

BACKGROUND: Diagnosis of lung injury requires invasive blood draws to measure oxygen tension in blood. This capability is nonexistent in austere settings and during prolonged field care (PFC), that is, medical care characterized by inability to evacuate casualties from the point of injury for up to 72 hours. We analyzed pulse-oximeter-derived noninvasive SpO2 and assessed the SpO2/FiO2 ratio (SFR) as a surrogate for the PaO2/FiO2 ratio (PFR), an accepted marker of lung function. We hypothesized that SFR is a suitable surrogate for PFR in a data set from animal models of combat-relevant trauma, PFC, and aeromedical evacuation. METHODS: Data from anesthetized swine (N = 30) subjected to combat relevant trauma, resuscitation, and critical care interventions were analyzed. Pairwise correlations and Bland-Altman and regression analyses were performed to compare PFR and SFR, based on averaged SpO2 values obtained from two monitoring devices. RESULTS: We performed 683 pairwise correlations. SpO2/FiO2 ratio was numerically higher than PFR with a 313 cutoff values for acute respiratory distress syndrome (ARDS) (PFR ≥300). Sensitivity/specificity for detection of mild ARDS was 75%/73% with a 200 to 300 PFR range corresponding to 252 to 312 SFR range. For moderate ARDS, sensitivity/specificity was 61%/93% with a 100 to 200 PFR range corresponding to 191 to 251 SFR range. For severe ARDS, sensitivity/specificity was 49%/97% with a 0 to 100 PFR range corresponding to 0 to 190 SFR range. For all groups, areas under the receiver operating characteristic curves ranged from 0.76 to 0.98. CONCLUSION: SpO2/FiO2 ratio is a useful surrogate for PFR when arterial blood gas testing is not available during dynamically changing physiologic conditions, for example, during austere conditions, PFC, or aeromedical evacuation, and may permit early detection of casualties in need of lung-specific life-saving interventions. Studies in critically ill humans are warranted.

Association between cytokine profiles and lung injury in COVID-19 pneumonia.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a new respiratory and systemic disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The purpose of the present study was to investigate the association between cytokine profiles and lung injury in COVID-19 pneumonia. METHODS: This retrospective study was conducted in COVID-19 patients. Demographic characteristics, symptoms, signs, underlying diseases, and laboratory data were collected. The patients were divided into COVID-19 with pneumonia and without pneumonia. CT severity score and PaO2/FiO2 ratio were used to assess lung injury. RESULTS: 106 patients with 12 COVID-19 without pneumonia and 94 COVID-19 with pneumonia were included. Compared with COVID-19 without pneumonia, COVID-19 with pneumonia had significantly higher serum interleukin (IL)-2R, IL-6, and tumor necrosis factor (TNF)-α. Correlation analysis showed that CT severity score and PaO2/FiO2 were significantly correlated with age, presence of any coexisting disorder, lymphocyte count, procalcitonin, IL-2R, and IL-6. In multivariate analysis, log IL6 was the only independent explanatory variables for CT severity score (ß = 0.397, p < 0.001) and PaO2/FiO2 (ß = - 0.434, p = 0.003). CONCLUSIONS: Elevation of circulating cytokines was significantly associated with presence of pneumonia in COVID-19 and the severity of lung injury in COVID-19 pneumonia. Circulating IL-6 independently predicted the severity of lung injury in COVID-19 pneumonia.

Prothrombin is a binding partner of the human receptor of advanced glycation end products.

The receptor for advanced glycation end products (RAGE) plays a key role in mammal physiology and in the etiology and progression of inflammatory and oxidative stress-based diseases. In adults, RAGE expression is normally high only in the lung where the protein concentrates in the basal membrane of alveolar Type I epithelial cells. In diseases, RAGE levels increase in the affected tissues and sustain chronic inflammation. RAGE exists as a membrane glycoprotein with an ectodomain, a transmembrane helix, and a short carboxyl-terminal tail, or as a soluble ectodomain that acts as a decoy receptor (sRAGE). VC1 domain is responsible for binding to the majority of RAGE ligands including advanced glycation end products (AGEs), S100 proteins, and HMGB1. To ascertain whether other ligands exist, we analyzed by MS the material pulled down by VC1 from human plasma. Twenty of 295 identified proteins were selected and associated to coagulation and complement processes and to extracellular matrix. Four of them contained a γ-carboxyl glutamic acid (Gla) domain, a calcium-binding module, and prothrombin (PT) was the most abundant. Using MicroScale thermophoresis, we quantified the interaction of PT with VC1 and sRAGE in the absence or presence of calcium that acted as a competitor. PT devoid of the Gla domain (PT des-Gla) did not bind to sRAGE, providing further evidence that the Gla domain is critical for the interaction. Finally, the presence of VC1 delayed plasma clotting in a dose-dependent manner. We propose that RAGE is involved in modulating blood coagulation presumably in conditions of lung injury.

Netrin-1 reduces lung ischemia-reperfusion injury by increasing the proportion of regulatory T cells.

OBJECTIVE: Inflammation is the primary mechanism of lung ischemia-reperfusion injury (LIRI) and neurologic factors can regulate inflammatory immune responses. Netrin-1 is an axonal guidance molecule, but whether Netrin-1 plays a role in LIRI remains unclear. METHODS: A mouse model of LIRI was established. Immunohistochemistry was used to detect expression of Netrin-1 and to enumerate macrophages and T cells in lung tissue. The proportion of regulatory T cells (Tregs) was assessed by flow cytometry. Levels of apoptosis were assessed by terminal deoxynucleotidyl transferase dUTP nick end staining. RESULTS: Numbers of macrophages and T cells in the lung tissues of mice with LIRI were elevated, while expression of netrin-1 was significantly decreased. Flow cytometry showed that the proportion of Tregs in mice with LIRI was significantly decreased. The proportion of Tregs among lymphocytes was positively correlated with netrin-1 expression. In vitro experiments showed that netrin-1 promoted an increase in Treg proportion through the A2b receptor. Animal experiments showed that netrin-1 could inhibit apoptosis and reduce T cell and macrophage infiltration by increasing the proportion of Tregs, ultimately reducing LIRI. Treg depletion using an anti-CD25 monoclonal antibody blocked the effects of netrin-1. CONCLUSION: Netrin-1 reduced LIRI by increasing the proportion of Tregs.

The development of various forms of lung injury with increasing tidal volume in normal rats.

Sixty-three, open-chest normal rats were subjected to mechanical ventilation (MV) with tidal volumes (VT) ranging from 7.5-39.5ml kg-1 and PEEP 2.3 cmH2O. Arterial blood gasses and pressure, and lung mechanics were measured during baseline ventilation (VT = 7.5ml kg-1) before and after test ventilation, when cytokine, von Willebrand factor (vWF), and albumin concentration in serum and broncho-alveolar lavage fluid (BALF), wet-to-dry weight ratio (W/D), and histologic injury scores were assessed. Elevation of W/D and serum vWF and cytokine concentration occurred with VT > 25ml kg-1. With VT > 30ml kg-1 cytokine and albumin concentration increased also in BALF, arterial oxygen tension decreased, lung mechanics and histology deteriorated, while W/D and vWF and cytokine concentration increased further. Hence, the initial manifestation of injurious MV consists of damage of extra-alveolar vessels leading to interstitial edema, as shown by elevated vWF and cytokine levels in serum but not in BALF. Failure of the endothelial-epithelial barrier occurs at higher stress-strain levels, with alveolar edema, small airway injury, and mechanical alterations.

Lung injury prediction scores: Clinical validation and C-reactive protein involvement in high risk patients.

OBJECTIVE: A study was made to validate two previously derived lung injury prediction scores (LIPS) for the prediction of acute respiratory distress syndrome (ARDS) in high risk intensive care patients, with the incorporation of C-reactive protein (CRP) for improving score accuracy. DESIGN: A prospective, observational cohort study was carried out. PATIENTS: A total of 200 patients with APACHE II score ≥15 and at least one ARDS risk factor upon ICU admission were included. INTERVENTIONS: Calculation of LIPS using formulas developed by Cartin-Ceba et al. (2009) and Trillo-Alvarez et al. (2011) (LIPS-2009 and LIPS-2011). C-reactive protein was measured upon admission (CRP-0) and after 48h (CRP-48). MAIN VARIABLES OF INTEREST: Independent variables: LIPS-2009, LIPS-2011 and CRP values. Dependent variable: development of ARDS. RESULTS: Eighty-eight patients (44%) developed ARDS after a median (Q1-Q3) of 2.5 (1.3-6.8) days. The LIPS-2009 and LIPS-2011 scores were 4 (3-6) and 5 (3.6-6.5) in ARDS patients compared to 2 (1-4) and 3.5 (1.5-4.5) in non-ARDS patients (p<0.001). CRP-48 was 96 (67.5-150.3)mg/L and 48 (24-96)mg/L in the two groups, respectively (p<0.001). ΔCRP (i.e., CRP-48 minus CRP-0) was significantly higher in the ARDS patients (p<0.001). The AUC was 0.740 and 0.738 for LIPS-2011 and LIPS-2009, respectively - the difference being nonsignificant (p=0.9, 0.9 and 0.8 for pairwise comparison of the different ROC curves). Integrating ΔCRP with LIPS-2011 using binary logistic regression analysis identified a new score (LIPS-N) with AUC 0.803, which was significantly higher than the AUC of LIPS-2011 (p=0.01). CONCLUSIONS: Both LIPS scores are equally effective in predicting ARDS in high risk ICU patients. Integrating the change in CRP within the score might improve its accuracy.