Risk Factors for the Mortality of Patients With Coronavirus Disease 2019 Requiring Extracorporeal Membrane Oxygenation in a Non-Centralized Setting: A Nationwide Study.

BACKGROUND: Limited data are available on the mortality rates of patients receiving extracorporeal membrane oxygenation (ECMO) support for coronavirus disease 2019 (COVID-19). We aimed to analyze the relationship between COVID-19 and clinical outcomes for patients receiving ECMO. METHODS: We retrospectively investigated patients with COVID-19 pneumonia requiring ECMO in 19 hospitals across Korea from January 1, 2020 to August 31, 2021. The primary outcome was the 90-day mortality after ECMO initiation. We performed multivariate analysis using a logistic regression model to estimate the odds ratio (OR) of 90-day mortality. Survival differences were analyzed using the Kaplan-Meier (KM) method. RESULTS: Of 127 patients with COVID-19 pneumonia who received ECMO, 70 patients (55.1%) died within 90 days of ECMO initiation. The median age was 64 years, and 63% of patients were male. The incidence of ECMO was increased with age but was decreased after 70 years of age. However, the survival rate was decreased linearly with age. In multivariate analysis, age (OR, 1.048; 95% confidence interval [CI], 1.010-1.089; P = 0.014) and receipt of continuous renal replacement therapy (CRRT) (OR, 3.069; 95% CI, 1.312-7.180; P = 0.010) were significantly associated with an increased risk of 90-day mortality. KM curves showed significant differences in survival between groups according to age (65 years) (log-rank P = 0.021) and receipt of CRRT (log-rank P = 0.004). CONCLUSION: Older age and receipt of CRRT were associated with higher mortality rates among patients with COVID-19 who received ECMO.

Impact of the early phase of the COVID-19 pandemic on emergency department-to-intensive care unit admissions in Korea: an interrupted time-series analysis.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic resulted in significant disruptions to critical care systems globally. However, research on the impact of the COVID-19 pandemic on intensive care unit (ICU) admissions via the emergency department (ED) is limited. Therefore, this study evaluated the changes in the number of ED-to-ICU admissions and clinical outcomes in the periods before and during the pandemic. METHODS: We identified all adult patients admitted to the ICU through level 1 or 2 EDs in Korea between February 2018 and January 2021. February 2020 was considered the onset point of the COVID-19 pandemic. The monthly changes in the number of ED-to-ICU admissions and the in-hospital mortality rates before and during the COVID-19 pandemic were evaluated using interrupted time-series analysis. RESULTS: Among the 555,793 adult ED-to-ICU admissions, the number of ED-to-ICU admissions during the pandemic decreased compared to that before the pandemic (step change, 0.916; 95% confidence interval [CI] 0.869-0.966], although the trend did not attain statistical significance (slope change, 0.997; 95% CI 0.991-1.003). The proportion of patients who arrived by emergency medical services, those transferred from other hospitals, and those with injuries declined significantly among the number of ED-to-ICU admissions during the pandemic. The proportion of in-hospital deaths significantly increased during the pandemic (step change, 1.054; 95% CI 1.003-1.108); however, the trend did not attain statistical significance (slope change, 1.001; 95% CI 0.996-1.007). Mortality rates in patients with an ED length of stay of ≥ 6 h until admission to the ICU rose abruptly following the onset of the pandemic (step change, 1.169; 95% CI 1.021-1.339). CONCLUSIONS: The COVID-19 pandemic significantly affected ED-to-ICU admission and in-hospital mortality rates in Korea. This study's findings have important implications for healthcare providers and policymakers planning the management of future outbreaks of infectious diseases. Strategies are needed to address the challenges posed by pandemics and improve the outcomes in critically ill patients.

Experience and perspectives of end-of-life care discussion and physician orders for life-sustaining treatment of Korea (POLST-K): a cross-sectional study.

BACKGROUND: This study aimed to identify the healthcare providers' experience and perspectives toward end-of-life care decisions focusing on end-of-life discussion and physician's order of life-sustaining treatment documentation in Korea which are major parts of the Life-Sustaining Treatment Act. METHODS: A cross-sectional survey was conducted using a questionnaire developed by the authors. A total of 474 subjects-94 attending physicians, 87 resident physicians, and 293 nurses-participated in the survey, and the data analysis was performed in terms of frequency, percentage, mean and standard deviation using the SPSS 24.0 program. RESULTS: Study results showed that respondents were aware of terminal illness and physician's order of life-sustaining treatment in Korea well enough except for some details. Physicians reported uncertainty in terminal state diagnosis and disease trajectory as the most challenging. Study participants regarded factors (related to relationships and communications) on the healthcare providers' side as the major impediment to end-of-life discussion. Study respondents suggested that simplification of the process and more staff are required to facilitate end-of-life discussion and documentation. CONCLUSION: Based on the study results, adequate education and training for better end-of-life discussion are required for future practice. Also, a simple and clear procedure for completing a physician's order of life-sustaining treatment in Korea should be prepared and legal and ethical advice would be required. Since the enactment of the Life-Sustaining Treatment Act, several revisions already have been made including disease categories, thus continuous education to update and support clinicians is also called for.

Comparison of the end-of-life decisions of patients with hospital-acquired pneumonia after the enforcement of the life-sustaining treatment decision act in Korea.

BACKGROUND: Although the Life-Sustaining Treatment (LST) Decision Act was enforced in 2018 in Korea, data on whether it is well established in actual clinical settings are limited. Hospital-acquired pneumonia (HAP) is a common nosocomial infection with high mortality. However, there are limited data on the end-of-life (EOL) decision of patients with HAP. Therefore, we aimed to examine clinical characteristics and outcomes according to the EOL decision for patients with HAP. METHODS: This multicenter study enrolled patients with HAP at 16 referral hospitals retrospectively from January to December 2019. EOL decisions included do-not-resuscitate (DNR), withholding of LST, and withdrawal of LST. Descriptive and Kaplan-Meier curve analyses for survival were performed. RESULTS: Of 1,131 patients with HAP, 283 deceased patients with EOL decisions (105 cases of DNR, 108 cases of withholding of LST, and 70 cases of withdrawal of LST) were analyzed. The median age was 74 (IQR 63-81) years. The prevalence of solid malignant tumors was high (32.4% vs. 46.3% vs. 54.3%, P = 0.011), and the ICU admission rate was lower (42.9% vs. 35.2% vs. 24.3%, P = 0.042) in the withdrawal group. The prevalence of multidrug-resistant pathogens, impaired consciousness, and cough was significantly lower in the withdrawal group. Kaplan-Meier curve analysis revealed that 30-day and 60-day survival rates were higher in the withdrawal group than in the DNR and withholding groups (log-rank P = 0.021 and 0.018). The survival of the withdrawal group was markedly decreased after 40 days; thus, the withdrawal decision was made around this time. Among patients aged below 80 years, the rates of EOL decisions were not different (P = 0.430); however, mong patients aged over 80 years, the rate of withdrawal was significantly lower than that of DNR and withholding (P = 0.001). CONCLUSIONS: After the LST Decision Act was enforced in Korea, a DNR order was still common in EOL decisions. Baseline characteristics and outcomes were similar between the DNR and withholding groups; however, differences were observed in the withdrawal group. Withdrawal decisions seemed to be made at the late stage of dying. Therefore, advance care planning for patients with HAP is needed.

Empiric Anti-Pseudomonal ß-Lactam Monotherapy Versus Fluoroquinolone Combination Therapy in Patients With Hospital-Acquired Pneumonia: A Multicenter Cohort Study With Propensity Score Matching.

BACKGROUND: There is insufficient data on the benefits of empiric antibiotic combinations for hospital-acquired pneumonia (HAP). We aimed to investigate whether empiric anti-pseudomonal combination therapy with fluoroquinolones decreases mortality in patients with HAP. METHODS: This multicenter, retrospective cohort study included adult patients admitted to 16 tertiary and general hospitals in Korea between January 1 and December 31, 2019. Patients with risk factors for combination therapy were divided into anti-pseudomonal non-carbapenem ß-lactam monotherapy and fluoroquinolone combination therapy groups. Primary outcome was 30-day mortality. Propensity score matching (PSM) was used to reduce selection bias. RESULTS: In total, 631 patients with HAP were enrolled. Monotherapy was prescribed in 54.7% (n = 345) of the patients, and combination therapy was prescribed in 45.3% (n = 286). There was no significant difference in 30-day mortality between the two groups (16.8% vs. 18.2%, P = 0.729) or even after the PSM (17.5% vs. 18.2%, P = 0.913). After the PSM, adjusted hazard ratio for 30-day mortality from the combination therapy was 1.646 (95% confidence interval, 0.782-3.461; P = 0.189) in the Cox proportional hazards model. Moreover, there was no significant difference in the appropriateness of initial empiric antibiotics between the two groups (55.0% vs. 56.8%, P = 0.898). The proportion of multidrug-resistant (MDR) pathogens was high in both groups. CONCLUSION: Empiric anti-pseudomonal fluoroquinolone combination therapy showed no survival benefit compared to ß-lactam monotherapy in patients with HAP. Caution is needed regarding the routine combination of fluoroquinolones in the empiric treatment of HAP patients with a high risk of MDR.

Comparison of survival rates between total knee arthroplasty after a previous anterior cruciate ligament reconstruction and primary total knee arthroplasty via propensity score matching.

INTRODUCTION: Although the survival rate of total knee arthroplasty (TKA) in patients treated with anterior cruciate ligament reconstruction (ACLR) is not as favorable as that in patients treated with primary TKA without ligament reconstruction, the exact survival rates and complications associated with these procedures are still controversial. Therefore, the purpose of the current study was to compare the revision rates of TKA in patients with knee osteoarthritis (OA) with a previous ACLR and those of patients with primary TKA with no history of knee surgery by using propensity score matching analysis. MATERIALS AND METHODS: A list of patients who underwent TKA from January 1, 2008 to May 31, 2019 was obtained from the Korean National Health Insurance database. Among these, 460 patients underwent TKA in a knee with a previous ACLR and 569,766 patients who underwent primary TKA due to degenerative OA. We performed propensity scoring matching to compare the revision rates including septic revision due to prosthetic joint infection after TKA and perioperative complication rates within 90 days after revision TKA between the two groups. RESULTS: Matched patients were assigned to one of the two groups (group A: 2,201 patients who underwent TKA due to primary OA, group B: 448 patients who underwent TKA in a knee with a previous ACLR) based on the propensity score. The total number of revisions per 1000 person-years was significantly higher in group B than in group A (10.16 vs 4.66, respectively). Group B showed a higher risk of revision than group A at 10 years post-TKA (hazard ratio: 2.49, 95% confidence interval: 1.30-4.77). However, group B showed a similar risk of septic revision as group A (p = 0.44). Perioperative complications within 90 days after TKA showed no significant differences between the groups. CONCLUSIONS: Surgeons should be aware of the relatively higher revision rate of TKA in patients who had previously undergone an ACLR compared to that in patients who underwent primary TKA.

Postvaccination Multisystem Inflammatory Syndrome in Adult with No Evidence of Prior SARS-CoV-2 Infection.

Ten days after receiving the first dose of coronavirus disease vaccine, a 22-year-old woman in South Korea experienced myocarditis, myopathy, pericarditis, and gastroenteritis; rash subsequently developed. There was no evidence of prior infection with severe acute respiratory syndrome coronavirus 2. The diagnosis was multisystem inflammatory syndrome resulting from coronavirus disease vaccination.

Prognostic value of tumor deposits for long-term oncologic outcomes in patients with stage III colorectal cancer: a systematic review and meta-analysis.

PURPOSE: The presence of tumor deposits (TDs) in colorectal cancer is associated with a poor prognosis. In patients with the concomitant presence of both TDs and lymph nodes (LNs), there is no staging option except for the number of positive LNs alone. Therefore, to determine the prognostic value of TDs in patients with stage III colorectal cancer, meta-analyses of survival outcomes of patients with TDs were performed comparing different subgroups based on the lymph node status. METHODS: PubMed, EMBASE, and the Cochrane Library were searched. Data were pooled, and overall effect size was calculated using random-effect models. Outcome measures were 5-year overall survival (OS) and 5-year disease-free survival (DFS). RESULTS: We included in the analysis 18 nonrandomized studies and 1 prospective study that examined 90,455 patients. N1c patients (TD + LN-) had worse 5-year DFS than TDs-negative stage III patients (TD-LN +) with a RR of 1.30 (95% CI 1.06-1.61, I2 = 47%). In subgroup analysis, N1c patients had worse 5-year DFS (RR = 1.60, 95% CI = 1.25-2.05, I2 = 40%) compared with TDs-negative N1 patients (TD-N1) whereas N1c patients had better 5-year OS (RR = 0.72, 95% CI = 0.62-0.83, I2 = 0%) and 5-year DFS (RR = 0.75, 95% CI = 0.57-0.99, I2 = 0%) compared with TDs-negative N2 patients (TD-N2). CONCLUSIONS: These results may suggest that current nodal staging for colorectal cancer needs modification. The presence of TDs may have more adverse oncologic outcomes than TDs-negative N1 patients. More studies are warranted to further verify these results.

Long-term oncologic outcomes of transanal TME compared with transabdominal TME for rectal cancer: a systematic review and meta-analysis.

BACKGROUND: Transanal total mesorectal excision (TaTME) appears to have favorable surgical and pathological outcomes. However, the evidence on survival outcomes remains unclear. We performed a meta-analysis to compare long-term oncologic outcomes of TaTME with transabdominal TME for rectal cancer. METHODS: PubMed, EMBASE, and the Cochrane Library were searched. Data were pooled, and overall effect size was calculated using random-effects models. Outcome measures were overall survival (OS), disease-free survival (DFS), and local and distant recurrence. RESULTS: We included 11 nonrandomized studies that examined 2,143 patients for the meta-analysis. There were no significant differences between the two groups in OS, DFS, and local and distant recurrence with a RR of 0.65 (95% CI 0.39-1.09, I2 = 0%), 0.79 (95% CI 0.57-1.10, I2 = 0%), 1.14 (95% CI 0.44-2.91, I2 = 66%), and 0.75 (95% CI 0.40-1.41, I2 = 0%), respectively. CONCLUSION: In terms of long-term oncologic outcomes, TaTME may be an alternative to transabdominal TME in patients with rectal cancer. Well-designed randomized trials are warranted to further verify these results.

Patient and hospital characteristics predict prolonged emergency department length of stay and in-hospital mortality: a nationwide analysis in Korea.

BACKGROUND: Prolonged emergency department length of stay (EDLOS) in critically ill patients leads to increased mortality. This nationwide study investigated patient and hospital characteristics associated with prolonged EDLOS and in-hospital mortality in adult patients admitted from the emergency department (ED) to the intensive care unit (ICU). METHODS: We conducted a retrospective cohort study using data from the National Emergency Department Information System. Prolonged EDLOS was defined as an EDLOS of ≥ 6 h. We constructed multivariate logistic regression models of patient and hospital variables as predictors of prolonged EDLOS and in-hospital mortality. RESULTS: Between 2016 and 2019, 657,622 adult patients were admitted to the ICU from the ED, representing 2.4% of all ED presentations. The median EDLOS of the overall study population was 3.3 h (interquartile range, 1.9-6.1 h) and 25.3% of patients had a prolonged EDLOS. Patient characteristics associated with prolonged EDLOS included night-time ED presentation and Charlson comorbidity index (CCI) score of 1 or higher. Hospital characteristics associated with prolonged EDLOS included a greater number of staffed beds and a higher ED level. Prolonged EDLOS was associated with in-hospital mortality after adjustment for selected confounders (adjusted odds ratio: 1.18, 95% confidence interval: 1.16-1.20). Patient characteristics associated with in-hospital mortality included age ≥ 65 years, transferred-in, artificially ventilated in the ED, assignment of initial triage to more urgency, and CCI score of 1 or higher. Hospital characteristics associated with in-hospital mortality included a lesser number of staffed beds and a lower ED level. CONCLUSIONS: In this nationwide study, 25.3% of adult patients admitted to the ICU from the ED had a prolonged EDLOS, which in turn was significantly associated with an increased in-hospital mortality risk. Hospital characteristics, including the number of staffed beds and the ED level, were associated with prolonged EDLOS and in-hospital mortality.

Relationship between the presence of dedicated doctors in rapid response systems and patient outcome: a multicenter retrospective cohort study.

BACKGROUND: Rapid response systems (RRSs) improve patients' safety, but the role of dedicated doctors within these systems remains controversial. We aimed to evaluate patient survival rates and differences in types of interventions performed depending on the presence of dedicated doctors in the RRS. METHODS: Patients managed by the RRSs of 9 centers in South Korea from January 1, 2016, through December 31, 2017, were included retrospectively. We used propensity score-matched analysis to balance patients according to the presence of dedicated doctors in the RRS. The primary outcome was in-hospital survival. The secondary outcomes were the incidence of interventions performed. A sensitivity analysis was performed with the subgroup of patients diagnosed with sepsis or septic shock. RESULTS: After propensity score matching, 2981 patients were included per group according to the presence of dedicated doctors in the RRS. The presence of the dedicated doctors was not associated with patients' overall likelihood of survival (hazard ratio for death 1.05, 95% confidence interval [CI] 0.93‒1.20). Interventions, such as arterial line insertion (odds ratio [OR] 25.33, 95% CI 15.12‒42.44) and kidney replacement therapy (OR 10.77, 95% CI 6.10‒19.01), were more commonly performed for patients detected using RRS with dedicated doctors. The presence of dedicated doctors in the RRS was associated with better survival of patients with sepsis or septic shock (hazard ratio for death 0.62, 95% CI 0.39‒0.98) and lower intensive care unit admission rates (OR 0.53, 95% CI 0.37‒0.75). CONCLUSIONS: The presence of dedicated doctors within the RRS was not associated with better survival in the overall population but with better survival and lower intensive care unit admission rates for patients with sepsis or septic shock.

The association between hospital length of stay before rapid response system activation and clinical outcomes: a retrospective multicenter cohort study.

BACKGROUND: Rapid response system (RRS) is being increasingly adopted to improve patient safety in hospitals worldwide. However, predictors of survival outcome after RRS activation because of unexpected clinical deterioration are not well defined. We investigated whether hospital length of stay (LOS) before RRS activation can predict the clinical outcomes. METHODS: Using a nationwide multicenter RRS database, we identified patients for whom RRS was activated during hospitalization at 9 tertiary referral hospitals in South Korea between January 1, 2016, and December 31, 2017. All information on patient characteristics, RRS activation, and clinical outcomes were retrospectively collected by reviewing patient medical records at each center. Patients were categorized into two groups according to their hospital LOS before RRS activation: early deterioration (LOS < 5 days) and late deterioration (LOS ≥ 5 days). The primary outcome was 28-day mortality and multivariable logistic regression was used to compare the two groups. In addition, propensity score-matched analysis was used to minimize the effects of confounding factors. RESULTS: Among 11,612 patients, 5779 and 5883 patients belonged to the early and late deterioration groups, respectively. Patients in the late deterioration group were more likely to have malignant disease and to be more severely ill at the time of RRS activation. After adjusting for confounding factors, the late deterioration group had higher 28-day mortality (aOR 1.60, 95% CI 1.44-1.77). Other clinical outcomes (in-hospital mortality and hospital LOS after RRS activation) were worse in the late deterioration group as well, and similar results were found in the propensity score-matched analysis (aOR for 28-day mortality 1.66, 95% CI 1.45-1.91). CONCLUSIONS: Patients who stayed longer in the hospital before RRS activation had worse clinical outcomes. During the RRS team review of patients, hospital LOS before RRS activation should be considered as a predictor of future outcome.

Rapid Response System Should Be Enhanced at Non-general Ward Locations: a Retrospective Multicenter Cohort Study in Korea.

BACKGROUND: A rapid response system (RRS) contributes to the safety of hospitalized patients. Clinical deterioration may occur in the general ward (GW) or in non-GW locations such as radiology or dialysis units. However, there are few studies regarding RRS activation in non-GW locations. This study aimed to compare the clinical characteristics and outcomes of patients with RRS activation in non-GW locations and in the GW. METHODS: From January 2016 to December 2017, all patients requiring RRS activation in nine South Korean hospitals were retrospectively enrolled and classified according to RRS activation location: GW vs non-GW RRS activations. RESULTS: In total, 12,793 patients were enrolled; 222 (1.7%) were non-GW RRS activations. There were more instances of shock (11.6% vs. 18.5%) and cardiac arrest (2.7% vs. 22.5%) in non-GW RRS activation patients. These patients also had a lower oxygen saturation (92.6% ± 8.6% vs. 88.7% ± 14.3%, P < 0.001) and a higher National Early Warning Score 2 (7.5 ± 3.4 vs. 8.9 ± 3.8, P < 0.001) than GW RRS activation patients. Although non-GW RRS activation patients received more intubation (odds ratio [OR], 3.135; P < 0.001), advanced cardiovascular life support (OR, 3.912; P < 0.001), and intensive care unit transfer (OR, 2.502; P < 0.001), their hospital mortality (hazard ratio, 0.630; P = 0.013) was lower than GW RRS activation patients upon multivariate analysis. CONCLUSION: Considering that there were more critically ill but recoverable cases in non-GW locations, active RRS involvement should be required in such locations.

Acute Kidney Injury and Kidney Damage in COVID-19 Patients.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This disease, which is quickly spreading worldwide, has high potential for infection and causes rapid progression of lung lesions, resulting in a high mortality rate. This study aimed to investigate the effects of SARS-CoV-2 infection on renal function in patients with COVID-19. METHODS: From February 21 to April 24, 2020, 66 patients diagnosed with COVID-19 at Chungnam National University Hospital were analyzed; all patients underwent routine urinalysis and were tested for serum creatinine, urine protein to creatinine ratio (PCR), and urine albumin to creatinine ratio (ACR). RESULTS: Acute kidney injury (AKI) occurred in 3 (4.5%) of the 66 patients, and 1 patient with AKI stage 3 underwent hemodialysis. Upon follow-up, all 3 patients recovered normal renal function. Compared with patients with mild COVID-19, AKI (n = 3) occurred in patients with severe COVID-19, of whom both urine PCR and ACR were markedly increased. CONCLUSION: The incidence of AKI was not high in COVID-19 patients. The lower mortality rate in SARS-CoV-2 infection compared with previous Middle East respiratory syndrome and SARS-CoV infections is thought to be associated with a low incidence of dysfunction in organs other than the lungs.

Prevalence of Malnutrition in Hospitalized Patients: a Multicenter Cross-sectional Study.

BACKGROUND: Malnutrition is associated with many adverse clinical outcomes. The present study aimed to identify the prevalence of malnutrition in hospitalized patients in Korea, evaluate the association between malnutrition and clinical outcomes, and ascertain the risk factors of malnutrition. METHODS: A multicenter cross-sectional study was performed with 300 patients recruited from among the patients admitted in 25 hospitals on January 6, 2014. Nutritional status was assessed by using the Subjective Global Assessment (SGA). Demographic characteristics and underlying diseases were compared according to nutritional status. Logistic regression analysis was performed to identify the risk factors of malnutrition. Clinical outcomes such as rate of admission in intensive care units, length of hospital stay, and survival rate were evaluated. RESULTS: The prevalence of malnutrition in the hospitalized patients was 22.0%. Old age (≥ 70 years), admission for medical treatment or diagnostic work-up, and underlying pulmonary or oncological disease were associated with malnutrition. Old age and admission for medical treatment or diagnostic work-up were identified to be risk factors of malnutrition in the multivariate analysis. Patients with malnutrition had longer hospital stay (SGA A = 7.63 ± 6.03 days, B = 9.02 ± 9.96 days, and C = 12.18 ± 7.24 days, P = 0.018) and lower 90-day survival rate (SGA A = 97.9%, B = 90.7%, and C = 58.3%, P < 0.001). CONCLUSION: Malnutrition was common in hospitalized patients, and resulted in longer hospitalization and associated lower survival rate. The rate of malnutrition tended to be higher when the patient was older than 70 years old or hospitalized for medical treatment or diagnostic work-up compared to elective surgery.

Hippo effector YAP directly regulates the expression of PD-L1 transcripts in EGFR-TKI-resistant lung adenocarcinoma.

Developments of EGFR-TKI and immunotherapy targeting the PD1/PD-L1 pathway are considered most important medical breakthroughs in lung cancer treatment. Nowadays, 3rd generation EGFR TKI is widely used for T790M positive 1st and 2nd EGFR-TKI resistant lung cancer patients. Immunotherapy is powerful option for lung cancer patients without drug targets and chemotherapy resistant patients. It also has changed the concept of conventional anti-cancer therapy in the point of regulating tumor microenvironment. There are many studies linking these two important pathways. Recent studies demonstrated that PD-L1 expression is significantly correlated to the mutation status of EGFR, and activation of EGFR signaling can also induce the expression of PD-L1. However, the real linker between PD-L1 and EGFR signaling remains to be revealed. Our previous study revealed that the Hippo pathway effector YAP confers EGFR-TKI resistance in lung adenocarcinoma, and inhibition of YAP restores sensitivity to EGFR-TKIs. Thus, we examined whether PD-L1 is relevant, in terms of conferring EGFR-TKI resistance and whether YAP directly regulates the expression of PD-L1 in this context. First, we compared the expression levels of PD-L1 and YAP between EGFR-TKI-resistant PC9 cells and the parental PC9 adenocarcinoma cells. The expression levels of both YAP and PD-L1 were markedly higher in the EGFR-TKI-resistant cells compared to the parental cells, suggesting differential expression pattern between two cell types. YAP knockdown significantly decreased the expression of PD-L1 in the EGFR-TKI-resistant cells, while YAP overexpression increased the expression of PD-L1 in the parental PC9 cells. Then, our results revealed that YAP regulates the transcription of PD-L1, and the YAP/TEAD complex binds to the PD-L1 promoter. Surprisingly, knockdown of PD-L1 was sufficient to decrease cell proliferation and wound healing in the EGFR-TKI-resistant PC9 cells. These data suggest a PD1-independent oncogenic function of PD-L1. The Hippo effector YAP plays a crucial role in linking the PD-L1 and EGFR-TKI resistance by directly regulating the expression of PD-L1 in lung cancer. Targeting PD-L1 directly or via YAP could provide an effective therapeutic strategy for EGFR-TKI-resistant lung adenocarcinoma.

Hippo pathway effector YAP inhibition restores the sensitivity of EGFR-TKI in lung adenocarcinoma having primary or acquired EGFR-TKI resistance.

The efficacy of EGFR-tyrosine kinase inhibitors (TKIs) is significantly limited by various resistance mechanisms to those drugs. The resistance to EGFR-TKI is largely divided by two classes; acquired resistance after EGFR-TKI treatment, and primary resistance marked by cancer cell's dependence on other oncogene, such as KRAS. YAP has emerged as critical oncogene in conferring drug resistance against targeted therapy. In this study, we evaluated the role of YAP in primary and acquired EGFR-TKI resistance using gefitinib-resistant A549 and PC9 cells and their parental cell lines. Our study revealed that EGFR-TKI resistance is associated with enhanced YAP activity. Notably, YAP activation was independent of the Hippo pathway. We confirmed that AXL is a downstream target of YAP that confers EGFR-TKI resistance. And our results showed that YAP can induce ERK activation in lung adenocarcinoma. The combination of YAP inhibition with EGFR-TKI overcomes primary and acquired EGFR-TKI resistance. We also found increased YAP expression in human lung cancer after acquiring EGFR-TKI resistance. Collectively, we suggest a novel EGFR-TKI resistance mechanism involving YAP activation and suggest targeting YAP and EGFR simultaneously may be a breakthrough treatment of primary and acquired EGFR-TKI resistant lung cancer.

The E3 ubiquitin ligase CHIP selectively regulates mutant epidermal growth factor receptor by ubiquitination and degradation.

Somatic mutation in the tyrosine kinase domain of epidermal growth factor receptor (EGFR) is a decisive factor for the therapeutic response to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in lung adenocarcinoma. The stability of mutant EGFR is maintained by various regulators, including heat shock protein 90 (Hsp90). The C terminus of Hsc70-interacting protein (CHIP) is a Hsp70/Hsp90 co-chaperone and exhibits E3 ubiquitin ligase activity. The high-affinity Hsp90-CHIP complex recognizes and selectively regulates their client proteins. CHIP also works with its own E3 ligase activity independently of Hsp70/Hsp90. Here, we investigated the role of CHIP in regulating EGFR in lung adenocarcinoma and also evaluated the specificity of CHIP's effects on mutant EGFR. In HEK 293T cells transfected with either WT EGFR or EGFR mutants, the overexpression of CHIP selectively decreased the expression of certain EGFR mutants (G719S, L747_E749del A750P and L858R) but not WT EGFR. In a pull-down assay, CHIP selectively interacted with EGFR mutants and simultaneously induced their ubiquitination and proteasomal degradation. The expressions of mutant EGFR in PC9 and H1975 were diminished by CHIP, while the expression of WT EGFR in A549 was nearly not affected. In addition, CHIP overexpression inhibited cell proliferation and xenograft's tumor growth of EGFR mutant cell lines, but not WT EGFR cell lines. EGFR mutant specific ubiquitination by CHIP may provide a crucial regulating mechanism for EGFR in lung adenocarcinoma. Our results suggest that CHIP can be novel therapeutic target for overcoming the EGFR TKI resistance.

Ethical issues recognized by critical care nurses in the intensive care units of a tertiary hospital during two separate periods.

This research aimed to investigate the changes in ethical issues in everyday clinical practice recognized by critical care nurses during two observation periods. We conducted a retrospective analysis of data obtained by prospective questionnaire surveys of nurses in the intensive care units (ICU) of a tertiary university-affiliated hospital in Seoul, Korea. Data were collected prospectively during two different periods, February 2002-January 2003 (Period 1) and August 2011-July 2012 (Period 2). Significantly fewer cases with ethical issues were reported in Period 2 than in Period 1 (89 cases [2.1%] of 4,291 ICU admissions vs. 51 [0.5%] of 9,302 ICU admissions, respectively; P < 0.001). The highest incidence of cases with identified ethical issues in both Periods occurred in MICU. The major source of ethical issues in Periods 1 and 2 was behavior-related. Among behaviorrelated issues, inappropriate healthcare professional behavior was predominant in both periods and mainly involved resident physicians. Ethical issue numbers regarding end-oflife (EOL) care significantly decreased in the proportion with respect to ethical issues during Period 2 (P = 0.044). In conclusion, the decreased incidence of cases with identified ethical issues in Period 2 might be associated with ethical enhancement related with EOL and improvements in the ICU care environment of the studied hospital. However, behaviorrelated issues involving resident physicians represent a considerable proportion of ethical issues encountered by critical care nurses. A systemic approach to solve behavior-related issues of resident physicians seems to be required to enhance an ethical environment in the studied ICU.

Nafamostat Mesilate Inhibits TNF-α-Induced Vascular Endothelial Cell Dysfunction by Inhibiting Reactive Oxygen Species Production.

Nafamostat mesilate (NM) is a serine protease inhibitor with anticoagulant and anti-inflammatory effects. NM has been used in Asia for anticoagulation during extracorporeal circulation in patients undergoing continuous renal replacement therapy and extra corporeal membrane oxygenation. Oxidative stress is an independent risk factor for atherosclerotic vascular disease and is associated with vascular endothelial function. We investigated whether NM could inhibit endothelial dysfunction induced by tumor necrosis factor-α (TNF-α). Human umbilical vein endothelial cells (HUVECs) were treated with TNF-α for 24 h. The effects of NM on monocyte adhesion, vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 (ICAM-1) protein expression, p38 mitogen-activated protein kinase (MAPK) activation, and intracellular superoxide production were then examined. NM (0.01~100 µg/mL) did not affect HUVEC viability; however, it inhibited the increases in reactive oxygen species (ROS) production and p66shc expression elicited by TNF-α (3 ng/mL), and it dose dependently prevented the TNF-α-induced upregulation of endothelial VCAM-1 and ICAM-1. In addition, it mitigated TNF-α-induced p38 MAPK phosphorylation and the adhesion of U937 monocytes. These data suggest that NM mitigates TNF-α-induced monocyte adhesion and the expression of endothelial cell adhesion molecules, and that the anti-adhesive effect of NM is mediated through the inhibition of p66shc, ROS production, and p38 MAPK activation.