A two-hit model of sepsis plus hyperoxia causes lung permeability and inflammation

Mouse models of acute lung injury (ALI) have been instrumental for studies of the biologic underpinnings of lung inflammation and permeability, but murine models of sepsis generate minimal lung injury. Our goal was to create a murine sepsis model of ALI that reflects the inflammation, lung edema, histologic abnormalities and physiologic dysfunction that characterize ALI. Using a cecal slurry (CS) model of polymicrobial abdominal sepsis and exposure to hyperoxia (95%), we systematically varied timing and dose of the CS injection, fluids and antibiotics and dose of hyperoxia. We found that CS alone had a high mortality rate that was improved with the addition of antibiotics and fluids. Despite this, we did not see evidence of ALI as measured by bronchoalveolar lavage (BAL) cell count, total protein, CXCL-1 or by lung wet:dry weight ratio. Addition of hyperoxia (95% FiO2) to CS immediately after CS injection increased BAL cell counts and CXCL-1 and lung wet:dry weight ratio but was associated with 40% mortality. Splitting the hyperoxia treatment into two 12 hour exposures (0-12 hours24-36 hours) after CS injection increased survival to 75% and caused significant lung injury compared to CS alone as measured by increased BAL total cell count (92500 vs 240000, p=0.0004), BAL protein (71 vs 103 ug/ml, p=0.0030, and lung wet:dry weight ratio (4.5 vs 5.5 p=0.0005), and compared to sham as measured by increased BAL CXCL-1 (20 vs 2372 pg/ml, p<0.0001), and histologic lung injury score (1.9 vs 4.2, p=0.0077). Additionally, our final model showed evidence of lung epithelial (increased BAL and plasma RAGE) and endothelial (increased Syndecan-1 and sulfated glycosaminoglycans) injury. In conclusion, we have developed a clinically relevant mouse model of sepsis-induced ALI using IP injection of CS, antibiotics and fluids, and hyperoxia. This clinically relevant model can be used for future studies of sepsis-induced ALI.

Sishen Pill Maintained Colonic Mucosal Barrier Integrity to Treat Ulcerative Colitis via Rho/ROCK Signaling Pathway

Sishen Pill (SSP) is a classical prescription of traditional Chinese medicine and often used to treat gastrointestinal diseases, including ulcerative colitis (UC). However, its mechanism is still unclear. We aimed to determine the mechanism of SSP in the treatment of UC by investigating if it maintains the integrity of the intestinal mucosal barrier via the Rho A/Rho kinase (ROCK) signaling pathway. Administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS) successfully induced chronic UC in rats, while the treatment effect of SSP was evaluated by body weight change, colonic length, colonic weight, colonic weight index, histological injury score, and pathological injury score after colitis rats were treated for 7 days. TNF-α and IL-1β levels were analyzed by ELISA, and the proteins of PI3K/Akt and RhoA/ROCK signaling pathway and junction proteins expression were measured by western blotting assay, and the distribution of Claudin 5 was shown by immunofluorescence. SSP significantly improved the clinical symptoms of colitis in rats and reduced the expression of p-RhoA, ROCK1, PI3K, and Akt in the colon mucosa, while it increased the expression of p-Rac and related proteins (Claudin-5, JAM1, VE-cadherin, and Connexin 43). In addition, SSP increased p-AMPKα and PTEN proteins expression, decreased Notch1 level, and hinted that activation of the PI3K/Akt signaling pathway was inhibited. In conclusion, SSP effectively treated chronic colitis induced by TNBS, which may have been achieved by inhibiting PI3K/Akt signal to suppress activation of the Rho/ROCK signaling pathway to finally maintain the integrity of the intestinal mucosal barrier.

Artificial intelligence to predict in-hospital mortality using novel anatomical injury score

The aim of the study is to develop artificial intelligence (AI) algorithm based on a deep learning model to predict mortality using abbreviate injury score (AIS). The performance of the conventional anatomic injury severity score (ISS) system in predicting in-hospital mortality is still limited. AIS data of 42,933 patients registered in the Korean trauma data bank from four Korean regional trauma centers were enrolled. After excluding patients who were younger than 19 years old and those who died within six hours from arrival, we included 37,762 patients, of which 36,493 (96.6%) survived and 1269 (3.4%) deceased. To enhance the AI model performance, we reduced the AIS codes to 46 input values by organizing them according to the organ location (Region-46). The total AIS and six categories of the anatomic region in the ISS system (Region-6) were used to compare the input features. The AI models were compared with the conventional ISS and new ISS (NISS) systems. We evaluated the performance pertaining to the 12 combinations of the features and models. The highest accuracy (85.05%) corresponded to Region-46 with DNN, followed by that of Region-6 with DNN (83.62%), AIS with DNN (81.27%), ISS-16 (80.50%), NISS-16 (79.18%), NISS-25 (77.09%), and ISS-25 (70.82%). The highest AUROC (0.9084) corresponded to Region-46 with DNN, followed by that of Region-6 with DNN (0.9013), AIS with DNN (0.8819), ISS (0.8709), and NISS (0.8681). The proposed deep learning scheme with feature combination exhibited high accuracy metrics such as the balanced accuracy and AUROC than the conventional ISS and NISS systems. We expect that our trial would be a cornerstone of more complex combination model.

Animal Study of a Newly Designed Metal Airway Brachytherapy Stent Loaded with Radioactive 125I Seeds

Aim: To evaluate dynamic tissue changes after airway stenting (AS) with a newly designed metal brachytherapy stent (BS) loaded with radioactive 125I seeds in normal rabbits.Method: Forty-five normal New Zealand white rabbits were divided into three groups (Group A: stent without seeds; Group B: stent with 0.4 mCi active seeds; Group C: stent with 0.8 mCi active seeds) and underwent AS under C-arm guidance. Then, 5 rabbits were sacrificed from each group at 2, 4, and 8 weeks for further examination. Laboratory tests (including routine blood tests, liver function, kidney function, electrolytes and ROS levels), gross observations, and tissue changes of Masson/hematoxylin-eosin staining, plus immunohistochemistry of α-SMA, NOX4, and TGF-β were performed at each time point.Result: All animals underwent AS successfully without procedure-related death, but one animal died at 6 weeks due to severe pulmonary infection in Group C. Apart from a transient increase in white blood cells (P < 0.05) and a gradual increase in ROS levels (P < 0.05), other blood test items showed no significant changes (P > 0.05). The brachytherapy injury score increased with irradiation dose accumulation (P < 0.05), but tissue hyperplasia at the stent end in Group C was less severe than that in Groups A and B (P < 0.05). Airway lateral fibrosis was observed in all groups by histopathologic analysis; however, fibrosis in Group C was more severe than that in Groups A and B (P < 0.05).Conclusion: The brachytherapy injury score increased with irradiation dose accumulation, while granulation tissue hyperplasia at the stent end was inhibited by 125I brachytherapy within 8 weeks.

Prolonged Emergency Department Stay at Referring Facilities: A Poor Trauma Performance Improvement Tool

Background Delays in the transfers of injured patients are perceived to increase morbidity and mortality and drive initiatives to limit the emergency department length of stay (LOS) at referring facilities (RF). RF LOS >4 hours is used for performance improvement (PI) with a large review burden with few improvement opportunities. Methods A statewide trauma registry 2013-2018 was used. Descriptive and inferential statistics including logistic regression were used to evaluate nongeriatric adult patients with ED LOS <12 hours. Paired data analyses utilizing prehospital (PH) and RF variables, vital signs (VS), Glasgow Coma Score–Motor component (GCS-M), RF LOS, mortality, trauma center hospital LOS (HLOS), and intensive care unit (ICU) LOS were performed. Results 13,721 of 56,702 transfer patients were selected. Mortality fell over time in all abbreviated injury score groups. GCS-M and systolic blood pressure (SBP) were correlated with mortality in both prehospital and RF data and highest in patients with abnormal GCS-M or SBP in both settings (38.0%, 30.1%). Examination of mortality over time in the group with abnormal VS showed SBP as the only variable with increasing mortality related to RF LOS. Average HLOS and ICU LOS were longest in patients with abnormal PH and RF SBP and GCS-M. Discussion Support for PI evaluation of RF LOS >4 hours was not identified. Increased survival over time is explained by early transfers of high mortality patients. Our data support existing efficient statewide transfers and recommend PI review of transfer patients with abnormal GCS-M and SBP in a narrower timeframe.

Abstract P242: The Role Of Kappa Opioid Receptors In The Development Of Hypertension And Kidney Injury In Sprague-Dawley Rats

The extensive use of opioid-based pain management strongly correlates with poor cardiovascular and cardiorenal outcomes. Our recent studies suggest that treatment with kappa opioid receptor (KOR) agonist BRL 52537 leads to the progression of chronic kidney disease (CKD) and aggravation of salt-sensitive hypertension. We hypothesize that stimulation of KORs leads to blood pressure elevation, albuminuria, and kidney damage in healthy Sprague-Dawley (SD) rats. To characterize the effect of the KOR agonist BRL 52537 on the development of blood pressure and kidney function in vivo , SD rats were treated with a daily i.v. bolus infusion of BRL 52537 or a corresponding vehicle. To test the contribution of KOR stimulation on calcium homeostasis in podocytes, BRL 52537 was used on freshly isolated glomeruli from SD rats. Single-channel analysis was applied to assess the effect of KORs stimulation on TRPC6 channel activity in the human immortalized podocytes. Chronic treatment with BRL 52537 leads to increased mean arterial pressure (88±1 vs 101±4 mmHg, vehicle vs treated, p<0.05), podocyte basal calcium (90±12 vs 216±16 a.u., vehicle vs treated, p<0.05), and GFB impairment in SD rats which is reflected by a transient increase in albumin excretion (Alb/cre ratio 0.35±0.1 vs 0.72±0.2, vehicle vs treated, p<0.05). Cumulative probability distribution analysis of the glomerular injury score revealed a rightward shift toward a high glomerular injury score in the group treated with BRL 52537 (p<0.05). Angiotensin II level was higher in a BRL-treated group (156±17 vs 232±59 pmol, vehicle vs treated, p=0.065); however, it did not reach a statistical difference. Acute application of BRL 52537 resulted in sustained calcium response (0.23±0.01 a.u., Fluo4/FuraRed, maximum calcium response) in freshly isolated glomeruli from SD rats. Furthermore, patch-clamp experiments in human immortalized podocytes (cell-attached configuration) revealed that BRL 52537 activated TRPC6 channels. Taken together, these data support the hypothesis that administration of opioids in SD rats leads to activation of the KOR/TRPC6 pathway, which in turn led to glomerular filtration barrier impairment, increased glomerular damage, and blood pressure elevation.

Survival of COVID-19 Patients With Respiratory Failure is Related to Temporal Changes in Gas Exchange and Mechanical Ventilation

Background: Respiratory failure due to coronavirus disease of 2019 (COVID-19) often presents with worsening gas exchange over a period of days. Once patients require mechanical ventilation (MV), the temporal change in gas exchange and its relation to clinical outcome is poorly described. We investigated whether gas exchange over the first 5 days of MV is associated with mortality and ventilator-free days at 28 days in COVID-19. Methods: In a cohort of 294 COVID-19 patients, we used data during the first 5 days of MV to calculate 4 daily respiratory scores: PaO2/FiO2 (P/F), oxygenation index (OI), ventilatory ratio (VR), and Murray lung injury score. The association between these scores at early (days 1-3) and late (days 4-5) time points with mortality was evaluated using logistic regression, adjusted for demographics. Correlation with ventilator-free days was assessed (Spearman rank-order coefficients). Results: Overall mortality was 47.6%. Nonsurvivors were older ( P < .0001), more male ( P = .029), with more preexisting cardiopulmonary disease compared to survivors. Mean PaO2 and PaCO2 were similar during this timeframe. However, by days 4 to 5 values for all airway pressures and FiO2 had diverged, trending lower in survivors and higher in nonsurvivors. The most substantial between-group difference was the temporal change in OI, improving 15% in survivors and worsening 11% in nonsurvivors ( P < .05). The adjusted mortality OR was significant for age (1.819, P = .001), OI at days 4 to 5 (2.26, P = .002), and OI percent change (1.90, P = .02). The number of ventilator-free days correlated significantly with late VR (−0.166, P < .05), early and late OI (−0.216, P < .01; −0.278, P < .01, respectively) and early and late P/F (0.158, P < .05; 0.283, P < .01, respectively). Conclusion: Nonsurvivors of COVID-19 needed increasing intensity of MV to sustain gas exchange over the first 5 days, unlike survivors. Temporal change OI, reflecting both PaO2 and the intensity of MV, is a potential marker of outcome in respiratory failure due to COVID-19.

Association Between C-Peptide Level and Subclinical Myocardial Injury

BackgroundPrevious studies have confirmed an association between C-peptide levels with the risk of cardiometabolic diseases. However, whether circulating C-peptide was related to subclinical myocardial injury (SC-MI) remains unknown.MethodsA total of 3,752 participants without a history of cardiovascular diseases were included in our study from National Health and Nutrition Examination Survey III (NHANES III). Multivariable linear regression was performed to explore the correlation between C-peptide and cardiac injury score (CIIS). Multivariate logistic regression was used to examine the association between C-peptide quartile and SC-MI.ResultsCirculating C-peptide was significantly associated with CIIS (β:0.09, 95% confidence interval [CI]: 0.00–0.17; p = 0.041). Compared with the lowest quartile, the highest quartile of circulating C-peptide increased a 1.48-fold risk of SC-MI (Odds ratio = 1.66, 95% CI: 1.18–1.87; p = 0.001).ConclusionsThe level of C-peptide was independently associated with CIIS and SC-MI, which could serve as a new risk factor of SC-MI.

Rat model of smoke inhalation-induced acute lung injury

BackgroundAcute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a lethal disease with limited therapeutic options and an unacceptably high mortality rate. Understanding the complex pathophysiological processes involved in the development of ALI/ARDS is critical for developing novel therapeutic strategies. Smoke inhalation (SI) injury is the leading cause of morbidity and mortality in patients with burn-associated ALI/ARDS; however, to our knowledge few reliable, reproducible models are available for pure SI animal model to investigate therapeutic options for ALI/ARDS without the confounding variables introduced by cutaneous burn or other pathology.ObjectiveTo develop a small animal model of pure SI-induced ALI and to use this model for eventual testing of novel therapeutics for ALI.MethodsRats were exposed to smoke using a custom-made smoke generator. Peripheral oxygen saturation (SpO2), heart rate, arterial blood gas, and chest X-ray (CXR) were measured before and after SI. Wet/dry weight (W/D) ratio, lung injury score and immunohistochemical staining of cleaved caspase 3 were performed on harvested lung tissues of healthy and SI animals.ResultsThe current study demonstrates the induction of ALI in rats after SI as reflected by a significant, sustained decrease in SpO2 and the development of diffuse bilateral pulmonary infiltrates on CXR. Lung tissue of animals exposed to SI showed increased inflammation, oedema and apoptosis as reflected by the increase in W/D ratio, injury score and cleaved caspase 3 level of the harvested tissues compared with healthy animals.ConclusionWe have successfully developed a small animal model of pure SI-induced ALI. This model is offered to the scientific community as a reliable model of isolated pulmonary SI-induced injury without the confounding variables of cutaneous injury or other systemic pathology to be used for study of novel therapeutics or other investigation.