Chau-Chyun Sheu

Genetic variants and risk of lung cancer in never smokers: a genome-wide association study.

BACKGROUND Lung cancer in individuals who have never smoked tobacco products is an increasing medical and public-health issue. We aimed to unravel the genetic basis of lung cancer in never smokers. METHODS We did a four-stage investigation. First, a genome-wide association study of single nucleotide polymorphisms (SNPs) was done with 754 never smokers (377 matched case-control pairs at Mayo Clinic, Rochester, MN, USA). Second, the top candidate SNPs from the first study were validated in two independent studies among 735 (MD Anderson Cancer Center, Houston, TX, USA) and 253 (Harvard University, Boston, MA, USA) never smokers. Third, further replication of the top SNP was done in 530 never smokers (UCLA, Los Angeles, CA, USA). Fourth, expression quantitative trait loci (eQTL) and gene-expression differences were analysed to further elucidate the causal relation between the validated SNPs and the risk of lung cancer in never smokers. FINDINGS 44 top candidate SNPs were identified that might alter the risk of lung cancer in never smokers. rs2352028 at chromosome 13q31.3 was subsequently replicated with an additive genetic model in the four independent studies, with a combined odds ratio of 1.46 (95% CI 1.26-1.70, p=5.94x10(-6)). A cis eQTL analysis showed there was a strong correlation between genotypes of the replicated SNPs and the transcription level of the gene GPC5 in normal lung tissues (p=1.96x10(-4)), with the high-risk allele linked with lower expression. Additionally, the transcription level of GPC5 in normal lung tissue was twice that detected in matched lung adenocarcinoma tissue (p=6.75x10(-11)). INTERPRETATION Genetic variants at 13q31.3 alter the expression of GPC5, and are associated with susceptibility to lung cancer in never smokers. Downregulation of GPC5 might contribute to the development of lung cancer in never smokers. FUNDING US National Institutes of Health; Mayo Foundation.

Clinical Characteristics and Outcomes of Sepsis-Related vs Non-Sepsis-Related ARDS

BACKGROUND ARDS may occur after either septic or nonseptic injuries. Sepsis is the major cause of ARDS, but little is known about the differences between sepsis-related and non-sepsis-related ARDS. METHODS A total of 2,786 patients with ARDS-predisposing conditions were enrolled consecutively into a prospective cohort, of which 736 patients developed ARDS. We defined sepsis-related ARDS as ARDS developing in patients with sepsis and non-sepsis-related ARDS as ARDS developing after nonseptic injuries, such as trauma, aspiration, and multiple transfusions. Patients with both septic and nonseptic risks were excluded from analysis. RESULTS Compared with patients with non-sepsis-related ARDS (n = 62), patients with sepsis-related ARDS (n = 524) were more likely to be women and to have diabetes, less likely to have preceding surgery, and had longer pre-ICU hospital stays and higher APACHE III (Acute Physiology and Chronic Health Evaluation III) scores (median, 78 vs 65, P < .0001). There were no differences in lung injury score, blood pH, Pao(2)/Fio(2) ratio, and Paco(2) on ARDS diagnosis. However, patients with sepsis-related ARDS had significantly lower Pao(2)/Fio(2) ratios than patients with non-sepsis-related ARDS patients on ARDS day 3 (P = .018), day 7 (P = .004), and day 14 (P = .004) (repeated-measures analysis, P = .011). Compared with patients with non-sepsis-related ARDS, those with sepsis-related had a higher 60-day mortality (38.2% vs 22.6%; P = .016), a lower successful extubation rate (53.6% vs 72.6%; P = .005), and fewer ICU-free days (P = .0001) and ventilator-free days (P = .003). In multivariate analysis, age, APACHE III score, liver cirrhosis, metastatic cancer, admission serum bilirubin and glucose levels, and treatment with activated protein C were independently associated with 60-day ARDS mortality. After adjustment, sepsis-related ARDS was no longer associated with higher 60-day mortality (hazard ratio, 1.26; 95% CI, 0.71-2.22). CONCLUSION Sepsis-related ARDS has a higher overall disease severity, poorer recovery from lung injury, lower successful extubation rate, and higher mortality than non-sepsis-related ARDS. Worse clinical outcomes in sepsis-related ARDS appear to be driven by disease severity and comorbidities.

Genetic variants associated with severe pneumonia in A/H1N1 influenza infection

The A/H1N1 influenza strain isolated in Mexico in 2009 caused severe pulmonary illness in a small number of exposed individuals. Our objective was to determine the influence of genetic factors on their susceptibility. We carried out a case–control association study genotyping 91 patients with confirmed severe pneumonia from A/H1N1 infection and 98 exposed but asymptomatic household contacts, using the HumanCVD BeadChip (Illumina, San Diego, CA, USA). Four risk single-nucleotide polymorphisms were significantly (p<0.0001) associated with severe pneumonia: rs1801274 (Fc fragment of immunoglobulin G, low-affinity IIA, receptor (FCGR2A) gene, chromosome 1; OR 2.68, 95% CI 1.69–4.25); rs9856661 (gene unknown, chromosome 3; OR 2.62, 95% CI 1.64–4.18); rs8070740 (RPA interacting protein (RPAIN) gene, chromosome 17; OR 2.67, 95% CI 1.63–4.39); and rs3786054 (complement component 1, q subcomponent binding protein (C1QBP) gene, chromosome 17; OR 3.13, 95% CI 1.89–5.17). All SNP associations remained significant after adjustment for sex and comorbidities. The SNPs on chromosome 17 were in linkage disequilibrium. These findings revealed that gene polymorphisms located in chromosomes 1 and 17 might influence susceptibility to development of severe pneumonia in A/H1N1 infection. Two of these SNPs are mapped within genes (FCGR2A, C1QBP) involved in the handling of immune complexes and complement activation, respectively, suggesting that these genes may confer risk due to increased activation of host immunity.

Serum bilirubin levels on ICU admission are associated with ARDS development and mortality in sepsis

Background: Hyperbilirubinaemia is a common complication of sepsis. Elevated bilirubin may induce inflammation and apoptosis. It was hypothesised that increased serum bilirubin on Intensive Care Unit (ICU) admission contributes to sepsis-related acute respiratory distress syndrome (ARDS). Methods: Serum bilirubin on ICU admission was measured in 1006 patients with sepsis. Serial serum bilirubin was analysed prospectively in patients with sepsis who had ARDS for a period of 28 days. The effects of clinical factors and variants of the UGT1A1 gene on serum bilirubin levels were determined. Outcomes were ARDS risk and mortality. Results: During 60-day follow-up, 326 patients with sepsis developed ARDS, of whom 144 died from ARDS. The hyperbilirubinaemia (⩾2.0 mg/dl) rate in patients with ARDS (22.4%) was higher than in those without ARDS (14.1%, p = 0.002). For each 1.0 mg/dl increase in admission bilirubin, ARDS risk and 28- and 60-day ARDS mortalities were increased by 7% (OR = 1.07; p = 0.003), 20% (OR = 1.20; p = 0.002) and 18% (OR = 1.18; p = 0.004), respectively. Compared with subjects with bilirubin levels <2.0 mg/dl, patients with hyperbilirubinaemia had higher risks of ARDS (OR = 2.12; p = 0.0007) and 28-day (OR = 2.24; p = 0.020) and 60-day ARDS mortalities (OR = 2.09; p = 0.020). In sepsis-related ARDS, serial bilirubin levels in non-survivors were consistently higher than in survivors (p<0.0001). Clinical variables explained 29.5% of the interindividual variation in bilirubin levels, whereas genetic variants of UGT1A1 contributed 7.5%. Conclusion: In sepsis, a higher serum bilirubin level on ICU admission is associated with subsequent ARDS development and mortality.

IL1RN coding variant is associated with lower risk of acute respiratory distress syndrome and increased plasma IL-1 receptor antagonist.

RATIONALE Acute respiratory distress syndrome (ARDS) behaves as a complex genetic trait, yet knowledge of genetic susceptibility factors remains incomplete. OBJECTIVES To identify genetic risk variants for ARDS using large scale genotyping. METHODS A multistage genetic association study was conducted of three critically ill populations phenotyped for ARDS. Stage I, a trauma cohort study (n = 224), was genotyped with a 50K gene-centric single-nucleotide polymorphism (SNP) array. We tested SNPs associated with ARDS at P < 5 × 10(-4) for replication in stage II, a trauma case-control population (n = 778). SNPs replicating their association in stage II (P < 0.005) were tested in a stage III nested case-control population of mixed subjects in the intensive care unit (n = 2,063). Logistic regression was used to adjust for potential clinical confounders. We performed ELISA to test for an association between ARDS-associated genotype and plasma protein levels. MEASUREMENTS AND MAIN RESULTS A total of 12 SNPs met the stage I threshold for an association with ARDS. rs315952 in the IL1RN gene encoding IL-1 receptor antagonist (IL1RA) replicated its association with reduced ARDS risk in stages II (P < 0.004) and III (P < 0.02), and was robust to clinical adjustment (combined odds ratio = 0.81; P = 4.2 × 10(-5)). Plasma IL1RA level was associated with rs315952C in a subset of critically ill subjects. The effect of rs315952 was independent from the tandem repeat variant in IL1RN. CONCLUSIONS The IL1RN SNP rs315952C is associated with decreased risk of ARDS in three populations with heterogeneous ARDS risk factors, and with increased plasma IL1RA response. IL1RA may attenuate ARDS risk.

Overexpression of Circulating c-Met Messenger RNA Is Significantly Correlated With Nodal Stage and Early Recurrence in Non-Small Cell Lung Cancer

BACKGROUND The c-met receptor and its ligand hepatocyte growth factor have been shown to be involved in tumor invasiveness and metastasis. Overexpression of c-met has been demonstrated in lung cancer tissues and cell lines, but the expression of c-met in peripheral blood (circulating c-met) has not been addressed. The molecular monitoring of circulating c-met could be helpful for selecting patients for adjuvant therapy. OBJECTIVES To investigate the expression of circulating c-met in non-small cell lung cancer (NSCLC) patients and to assess its prognostic implications. METHODS We quantified the levels of c-met messenger RNA (mRNA) in paired tumor and normal lung tissues and their peripheral bloods in 45 patients with NSCLC by real-time polymerase chain reaction (PCR). The expression status of c-met protein in tumor tissues was further evaluated by immunohistochemistry. RESULTS c-Met mRNA was significantly higher by 1.5 to 11 times in 34 of 45 tumor tissues (75.5%) than it was in their normal counterparts by real-time PCR. A comparison of this assay to immunohistochemistry suggested that real-time PCR was more sensitive than immunohistochemistry (27 of 45 tumor tissues, 60.0%) for the detection of c-met (p = 0.016). Of these patients with overexpression of c-met in tumors, 67.6% (23 of 34 patients) expressed higher amounts of circulating c-met by 1.4 to 8 times that of the normal control subjects. In addition, overexpression of circulating c-met was significantly correlated with nodal (N) stage (p = 0.011), but weakly correlated with tumor (T) stage (p = 0.056) and overall stages (p = 0.054) in patients with NSCLC. However, no correlations were found among circulating c-met and other factors such as age, gender, and pathologic types. Moreover, by univariate analysis, circulating c-met overexpression and pathologic stages (including T and N stages) were the most important factors correlated with early recurrence (p < 0.05). Only the circulating c-met remained as an independent predictor of early recurrence (hazard ratio, 3.94; 95% confidence interval, 1.17 to 13.33; p = 0.027) after Cox regression multivariate analysis. CONCLUSIONS Overexpression of circulating c-met is significantly correlated with the N stage and early recurrence. Moreover, early recurrence is frequently noted in patients with overexpression of circulating c-met, indicating that circulating c-met is an independent negative prognostic indicator in NSCLC.

Interactions Among Genetic Variants in Apoptosis Pathway Genes, Reflux Symptoms, Body Mass Index, and Smoking Indicate Two Distinct Etiologic Patterns of Esophageal Adenocarcinoma

PURPOSE Apoptosis pathway, gastroesophageal reflux symptoms (reflux), higher body mass index (BMI), and tobacco smoking have been individually associated with esophageal adenocarcinoma (EA) development. However, how multiple factors jointly affect EA risk remains unclear. PATIENTS AND METHODS In total, 305 patients with EA and 339 age- and sex-matched controls were studied. High-order interactions among reflux, BMI, smoking, and functional polymorphisms in five apoptotic genes (FAS, FASL, IL1B, TP53BP, and BAT3) were investigated by entropy-based multifactor dimensionality reduction (MDR), classification and regression tree (CART), and traditional logistic regression (LR) models. RESULTS In LR analysis, reflux, BMI, and smoking were significantly associated with EA risk, with reflux as the strongest individual factor. No individual single nucleotide polymorphism was associated with EA susceptibility. However, there was a two-way interaction between IL1B + 3954C>T and reflux (P = .008). In both CART and MDR analyses, reflux was also the strongest individual factor for EA risk. In individuals with reflux symptoms, CART analysis indicated that strongest interaction was among variant genotypes of IL1B + 3954C>T and BAT3S625P, higher BMI, and smoking (odds ratio [OR], 5.76; 95% CI, 2.48 to 13.38), a finding independently found using MDR analysis. In contrast, for participants without reflux symptoms, the strongest interaction was found between higher BMI and smoking (OR, 3.27; 95% CI, 1.88 to 5.68), also echoed by entropy-based MDR analysis. CONCLUSION Although a history of reflux is an important risk for EA, multifactor interactions also play important roles in EA risk. Gene-environment interaction patterns differ between patients with and without reflux symptoms.

Genetic Polymorphisms of Peptidase Inhibitor 3 (Elafin) Are Associated with Acute Respiratory Distress Syndrome

Peptidase inhibitor 3 (PI3, elafin) is a protease inhibitor produced locally in the lung, where it plays a central role in controlling excessive activity of neutrophil elastase. Our previous study revealed that PI3 gene expression is down-regulated during the acute stage of acute respiratory distress syndrome (ARDS). We conducted a case-control study to investigate whether genetic variants in PI3 gene are associated with ARDS development. Based on resequencing data from 29 unrelated white subjects, three tagging single-nucleotide polymorphisms were selected and genotyped in a prospective cohort consisting of 449 white patients with ARDS (cases) and 1,031 critically ill patients (at-risk control subjects). We found that the variant allele of rs2664581 (T34P) was significantly associated with increased ARDS risk (odds ratio [OR], 1.35; 95% confidence interval [CI], 1.09-1.67; P = 0.006; false discovery rate adjusted P = 0.018). Moreover, this association was stronger among subjects with extrapulmonary injury. The common haplotype Hap2 (TTC), containing the variant allele of rs2664581, was also identified as a risk haplotype for ARDS (OR, 1.31; 95% CI, 1.05-1.64; P = 0.015). Furthermore, the rs2664581 polymorphism was associated with circulating PI3 levels in multivariate analyses. Patients with ARDS homozygous for the wild-type A allele of rs2664581 showed significant lower PI3 plasma level (P = 0.019) at ARDS onset as compared with those homozygous or heterozygous for the variant C allele. Our data suggest that polymorphisms in PI3 gene are significantly associated with ARDS risk and with circulating PI3 levels.

Admission Time and Outcomes of Patients in a Medical Intensive Care Unit

Studies have shown that weekend or night admissions to intensive care units (ICUs) are associated with increased mortality in critically ill patients. Our study aimed to evaluate the effects of admission time and day on patient outcomes in a medical ICU equipped with patient management guidelines, and staffed by intensivists on call for 24 hours, who led the morning rounds on all days of the week but did not stay in‐house overnight. The study enrolled 611 consecutive patients admitted to a 26‐bed medical ICU in a university hospital during a 7‐month period. We divided them into two groups, which we labeled as “office hours” (08:00–18:00 on weekdays) and “non‐office hours” (18:00–08:00 on weekdays, and all times on weekends) according to their ICU admission times. The clinical outcomes were compared between the groups. The effects of admission on weekends, at night, and various days of the week on hospital mortality were also evaluated. Our results showed that there were no significant differences in ICU and hospital mortalities between patients admitted during office hours and those admitted during non‐office hours (27.2% vs. 27.4%, p = 1.000; 38.9% vs. 37.6%, p = 0.798). The ICU length of stay, ICU‐free time within 21 days, and length of stay in the hospital were also comparable in both groups. Among the 392 patients requiring mechanical ventilation, the ventilator outcomes were not significantly different between those in the office‐hour group and the non‐office‐hour group. Multivariate logistic regression analyses showed that the adjusted odds of hospital mortality were not significantly higher for patients admitted to our ICU on weekends, at night, or on any days of the week. In conclusion, our results showed that non‐office‐hour admissions to our medical ICU were not associated with poorer ICU, hospital, and ventilator outcomes, compared with office‐hour admissions. Neither were time of day and day of the week admissions to our ICU associated with significant differences in hospital mortality.

Distinct and replicable genetic risk factors for acute respiratory distress syndrome of pulmonary or extrapulmonary origin

Background The role of genetics in the development of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) from direct or indirect lung injury has not been specifically investigated. The aim of this study was to identify genetic variants contributing to ALI/ARDS from pulmonary or extrapulmonary causes. Methods We conducted a multistage genetic association study. We first performed a large-scale genotyping (50K ITMAT-Broad_CARe Chip) in 1717 critically ill Caucasian patients with either pulmonary or extrapulmonary injury, to identify single nucleotide polymorphisms (SNPs) associated with the development of ARDS from direct or indirect insults to the lung. Identified SNPs (p≤0.0005) were validated in two separated populations (Stage II), with trauma (Population I; n=765) and pneumonia/pulmonary sepsis (Population II; n=838), as causes for ALI/ARDS. Genetic variants replicating their association with trauma related-ALI in Stage II were validated in a second trauma-associated ALI population (n=224, Stage III). Results In Stage I, non-overlapping SNPs were significantly associated with ARDS from direct/indirect lung injury, respectively. The association between rs1190286 (POPDC3) and reduced risk of ARDS from pulmonary injury was validated in Stage II (p<0.003). SNP rs324420 (FAAH) was consistently associated with increased risk of ARDS from extrapulmonary causes in two independent ALI-trauma populations (p<0.006, Stage II; p<0.05, Stage III). Meta-analysis confirmed these associations. Conclusions Different genetic variants may influence ARDS susceptibility depending on direct versus indirect insults. Functional SNPs in POPDC3 and FAAH genes may be driving the association with direct and indirect ALI/ARDS, respectively.