Improved diagnostic accuracy with three lung tumor markers compared to six-marker panel.

Background: Combining multiple tumor markers increases sensitivity for lung cancer diagnosis in the cost of false positive. However, some would like to check as many as tumor markers in the fear of missing cancer. We though to propose a panel of fewer tumor markers for lung cancer diagnosis. Methods: Patients with suspected lung cancer who simultaneously underwent all six tests [carcinoembryonic antigen (CEA), cytokeratin-19 fragment (CYFRA), squamous cell carcinoma-associated antigen (SCC), neuron-specific enolase (NSE), pro-gastrin-releasing peptide (ProGRP), and sialyl Lewis-X antigen (SLX)] were included. Tumor markers with significant impact on the lung cancer in a logistic regression model were included in our panel. Area under the curve (AUC) was compared between our panel and the panel of all six. Results: We included 1,733 [median 72 years, 1,128 men, 605 women, 779 (45%) confirmed lung cancer]. Logistic regression analysis suggested CEA, CYFRA, and NSE were independently associated with the lung cancer diagnosis. The panel of these three tumor markers [AUC =0.656, 95% confidence interval (CI): 0.630-0.682, sensitivity 0.650, specificity 0.662] had better (P<0.001) diagnostic performance than six tumor markers (AUC =0.575, 95% CI: 0.548-0.602, sensitivity 0.829, specificity 0.321). Conclusions: Compared to applying all six markers (at least one marker above the upper limit of normal), the panel with three markers (at least one marker above the upper limit of normal) led to a better predictive value by lowering the risk of false positives.

ILD-GAP combined with the monocyte ratio could be a better prognostic prediction model than ILD-GAP in patients with interstitial lung diseases.

BACKGROUND: The ILD-GAP scoring system is known to be useful in predicting prognosis in patients with interstitial lung disease (ILD). An elevated monocyte count was associated with increased risks of IPF poor prognosis. We examined whether the ILD-GAP scoring system combined with the monocyte ratio (ILD-GAPM) is superior to the conventional ILD-GAP model in predicting ILD prognosis. METHODS: In patients with ILD treated between April 2013 and April 2017, we were retrospectively assessed the relationships between baseline clinical parameters, including age, sex, Charlson Comorbidity Index score (CCIS), ILD diagnosis, blood biomarkers, pulmonary function test results, and disease outcomes. In ILD patients were included idiopathic pulmonary fibrosis (IPF), idiopathic nonspecific interstitial pneumonia (iNSIP), collagen vascular disease-related interstitial pneumonia (CVD-IP), chronic hypersensitivity pneumonitis (CHP), and unclassifiable ILD (UC-ILD). We also assessed the ability to predict prognosis was compared between the ILD-GAP and ILD-GAPM models. RESULTS: A total of 179 patients (mean age, 73 years) were assessed. All of them were taken pulmonary function test, including percentage predicted diffusion capacity for carbon monoxide. ILD patients included 56 IPF cases, 112 iNSIP and CVD-IP cases, 6 CHP cases and 5 UC-ILD cases. ILD-GAPM provided a greater area under the receiver-operating characteristic curve (0.747) than ILD-GAP (0.710) for predicting 3-year ILD-related events. Furthermore, the log-rank test showed that the Kaplan-Meier curves in ILD-GAPM were significantly different by stage (P = 0.015), but not by stage in ILD-GAP (P = 0.074). CONCLUSIONS: The ILD-GAPM model may be a more accurate predictor of prognosis for ILD patients than the ILD-GAP model.

Bilateral Pneumothorax after a Transbronchial Lung Cryobiopsy for Interstitial Lung Disease.

We herein report a case of bilateral pneumothorax after a unilateral transbronchial lung cryobiopsy (TBLC). A 73-year-old man with no history of cardiothoracic surgery underwent a TBLC for the reevaluation of interstitial lung disease. Five hours later, he developed bilateral pneumothorax, pneumomediastinum, and subcutaneous emphysema. He underwent bilateral chest drainage and was discharged 18 days later. The lung biopsy specimens obtained from the TBLC contained visceral pleura and bronchial cartilage, suggesting bronchial injury as the cause of the bilateral pneumothorax.

Serum heme oxygenase-1 as a prognostic biomarker in patients with acute exacerbation of interstitial lung disease.

Serum heme oxygenase (HO)-1 level has been reported as a clinically reliable diagnostic biomarker for acute exacerbation of interstitial lung disease (ILD); however, its utility for predicting mortality among these patients is unclear. Serum HO-1 levels of patients newly diagnosed with acute exacerbation of ILD were measured at the time of initiating steroid pulse therapy. The relationship between serum HO-1 and various other serum biomarkers, change in HRCT findings, and disease prognosis at 12 weeks after diagnosis of acute exacerbation was evaluated in 51 patients, of whom 17 (33%) had idiopathic pulmonary fibrosis (IPF). Serum HO-1 was higher in patients with acute exacerbation of IPF than in patients with acute exacerbation of other ILDs. Serum HO-1 levels were higher in patients who died within these 12 weeks than in survivors. Among age, sex, comorbidities, IPF diagnosis, HRCT findings, and blood biomarkers, serum HO-1 was a primary predictor of 12-week mortality. In 41 patients who underwent repeat HRCT, serum HO-1 was higher in patients with honeycomb progression than in those without. Serum HO-1 measurement could be useful for evaluating disease mortality and morbidity of patients with acute exacerbation of ILDs.

＜Editors' Choice＞ Comparison of clinical features between patients with acute exacerbation of idiopathic interstitial pneumonia and collagen vascular disease-associated interstitial pneumonia.

Acute exacerbation (AE) of interstitial pneumonia (IP) shows poor prognosis, due to the typical histological pattern of diffuse alveolar damage superimposed upon lung fibrosis. The previous reports comparing clinical features between AE of idiopathic interstitial pneumonias (IIPs) and those of IPs with known etiology are limited. We retrospectively compared clinical parameters including age, sex, Charlson Comorbidity Index score (CCIS), blood biomarkers at diagnosis of AE, treatment, and 3-month mortality between patients with AE of IIPs and collagen vascular disease-associated interstitial pneumonia (CVD-IP). We assessed 85 patients, comprising 66 patients with AE of IIPs (78%) and 19 patients with AE of CVD-IP (22%). The least absolute shrinkage and selection operator regression selected CCIS (hazard ratio, 1.281; 95% confidence interval, 1.055-1.556; P = 0.012) and log serum lactate dehydrogenase (LDH) (hazard ratio, 6.267; 95% confidence interval, 2.172-18.085; P < 0.001) as significant predictors of 3-month mortality among these patients. Also, the adjusted survival curves using sex, CCIS, and serum LDH showed no significant differences between these two groups. In conclusion, among AE patients, CCIS and serum LDH level may be more important prognostic factors for 3-month mortality rather than two classification of IP subtypes: IIPs and CVD-IP.

The clinical impact of comorbidities among patients with idiopathic pulmonary fibrosis undergoing anti-fibrotic treatment: A multicenter retrospective observational study.

BACKGROUND: Among patients with idiopathic pulmonary fibrosis (IPF), few studies have investigated the clinical impact of anti-fibrotic treatment (AFT) with and without comorbidities. The aim of the study was to determine whether Charlson Comorbidity Index score (CCIS) can predict the efficacy of AFT in patients with IPF. METHODS: We retrospectively assessed data extracted from the medical records of IPF patients who received anti-fibrotic agents between 2009 and 2019. The collected data included age, sex, CCIS, pulmonary function test, high-resolution computed tomography (HRCT) pattern, gender/age/physiology (GAP) score, and 3-year IPF-related events defined as the first acute exacerbation or death within 3 years after starting AFT. RESULTS: We assessed 130 patients (median age, 74 years) who received nintedanib (n = 70) or pirfenidone (n = 60). Median duration of AFT was 425 days. Patients were categorized into high (≥ 3 points) and low (≤ 2 points) CCIS groups. There was no significant difference between the groups in terms of age, sex, duration of AFT, GAP score, or incidence of usual interstitial pneumonia pattern on HRCT except percentage predicted diffusion capacity of lung for carbon monoxide. Also, significant difference was not seen between the groups for 3-year IPF-related events (P = 0.75). Especially, in the low CCIS group but not the high CCIS group, the longer duration of AFT had better disease outcome. CONCLUSION: In the present study, we could not show any relation between CCIS and IPF disease outcomes in patients undergoing AFT, though the longer duration of AFT might be beneficial for IPF outcomes among patients with low CCIS.

Acute Exacerbation and Proposed Criteria for Progressive Pulmonary Fibrosis in Patients with Fibrotic Hypersensitivity Pneumonitis and Idiopathic Pulmonary Fibrosis.

BACKGROUND: Acute exacerbation (AE) occasionally develops in the course of fibrotic hypersensitivity pneumonitis (HP). OBJECTIVE: The aim of the study was to compare AE of fibrotic HP with that of idiopathic pulmonary fibrosis (IPF). METHODS: Consecutive patients with pathologically confirmed fibrotic HP and IPF diagnosed based on a multidisciplinary discussion were included in the analysis. AE in patients with fibrotic HP and IPF was evaluated retrospectively. RESULTS: This study included 309 and 160 patients with fibrotic HP and IPF, respectively. Their 50% survival times were 96.1 and 78.0 months, respectively (hazard ratio [HR]: 0.54 [95% confidence interval, CI: 0.36-0.77], log-rank test; p < 0.001). Notably, the cumulative AE rates of fibrotic HP were 3% at 1 year and 10% at 3 years. Moreover, the corresponding rates of IPF were 8% at 1 year and 20% at 3 years (HR: 0.66 [95% CI: 0.45-0.93], log-rank test; p = 0.034). The 90-day survival rates from the AE onset of fibrotic HP and IPF were 75% and 64%, respectively (HR: 0.51 [95% CI: 0.31-0.83], log-rank test; p = 0.006). The respiratory function test on the physiological criteria of progressive pulmonary fibrosis (PPF) was a predictor of AE in fibrotic HP. However, the high-resolution CT (HRCT) changes in the criteria of PPF were not. Nevertheless, both the physiological and radiological criteria of PPF were a predictor of AE of IPF. CONCLUSION: AE of fibrotic HP has a lesser prognostic effect than that of IPF. HRCT criteria for PPF were not a risk factor for AE in patients with fibrotic HP.

Safety and Efficacy of Combination Therapy of Remdesivir, Baricitinib, and High-dose Steroids in Patients Hospitalized with Moderate to Severe COVID-19.

Objective Dexamethasone, remdesivir (REM), and baricitinib (BAR) are commonly used to treat coronavirus disease 2019 (COVID-19). High-dose steroids have also been reported to be well tolerated, even when used in combination with multiple drugs. In this retrospective study, we assessed the safety and therapeutic efficacy of a three-drug combination of high-dose steroids, REM, and BAR in hospitalized COVID-19 patients. Methods We retrospectively evaluated the safety and efficacy of three-drug combination therapy. Patients We evaluated 107 patients hospitalized with moderate or severe COVID-19 who underwent 3-drug combination therapy with high-dose steroids (80 mg of methylprednisolone or more, REM, and BAR) in our institution from December 2020 to June 2021. The mean age was 62.1±13.7 years old, and 71.2% were men. The severity of the study patients was as follows: 18 (16.8%) with an 8-category ordinal score of 4, 84 (78.5%) with a score of 5, and 5 (4.7%) with a score of 6. Results The frequency of high-grade adverse events was low, except for hyperglycemia (n=59, 45.8%). The median duration from symptom onset to the start of three-drug combination therapy was eight days. All but one of the patients treated with the combination therapy improved. The median time to improvement by 1 category of the eight-category ordinal score was 6 days, and the 28-day mortality was 0.9%. Conclusion This study showed the safety profile of three-drug combination therapy of high-dose steroids, REM, and BAR in moderate to severe COVID-19 patients. The three-drug combination therapy is well tolerated and has the potential to prevent exacerbation of severity.

Identification of a Novel Gene Involved in Cell-to-cell Communication-induced Cell Death and eDNA Production in Streptococcus mutans.

Streptococcus mutans is a major caries-causing bacterium that forms firmly attached biofilms on tooth surfaces. Biofilm formation by S. mutans consists of polysaccharide-dependent and polysaccharide-independent processes. Among polysaccharide-independent processes, extracellular DNA (eDNA) mediates the initial attachment of cells to surfaces. We previously reported that the secreted peptide signal, competence-stimulating peptide (CSP) induced cell death in a subpopulation of cells, leading to autolysis-mediated eDNA release. The autolysin gene lytF, the expression of which is stimulated by CSP, has been shown to mediate CSP-dependent cell death, while cell death was not entirely abolished in the lytF deletion mutant, indicating the involvement of other factors. To identify novel genes involved in CSP-dependent cell death, we herein compared transcriptomes between live and dead cells derived from an isogenic population. The results obtained revealed the accumulation of several mRNAs in dead cells. The deletion of SMU_1553c, a putative bacteriocin gene, resulted in significant reductions in CSP-induced cell death and eDNA production levels from those in the parental strain. Moreover, in the double mutant strain of lytF and SMU_1553c, cell death and eDNA production in response to synthetic CSP were completely abolished under both planktonic and biofilm conditions. These results indicate that SMU_1553c is a novel cell death-related factor that contributes to CSP-dependent cell death and eDNA production.

A novel catheter ablation strategy for non-paroxysmal atrial fibrillation combining cryoballoon, radiofrequency, and Marshall-vein ethanol ablations.

BACKGROUNDS: Catheter ablation for non-paroxysmal atrial fibrillation (non-PAF) remains challenging and more effective strategy has been required to reduce postoperative arrhythmia recurrences. This study aims to investigate the efficacy and safety of a novel extensive ablation strategy for non-PAF, that is based on a combination of cryoballoon (CBA), radiofrequency (RFA), and Marshall-vein ethanol ablations (EA-VOM). METHODS: The study was a single-center, retrospective observational study. We enrolled 171 consecutive patients who underwent de-novo catheter ablation for non-PAF under conscious sedation with a novel extensive ablation strategy that included CBA for pulmonary vein isolation (PVI) and left atrial roof ablation (LARA), RFA for mitral isthmus (MI) ablation, superior vena cava isolation, and other linear ablations and EA-VOM. Recurrence of atrial arrhythmias over 1 year, procedure outcomes, and procedure-related complications were investigated. RESULTS: A total of 139 (81.3%) patients remained in sinus rhythm during 1-year follow-up. Of the 139 patients, 51 patients (29.8%) received antiarrhythmic drugs. The mean procedure time was 204 ± 45 min. PVI and LARA ablation by CBA and MI block by RFA and EA-VOM were completed in 171 (100%) and 166 (97.1%) patients, respectively. No serious procedure-related complications were observed except for one case of delayed pericardial effusion. CONCLUSION: Approximately 80% of the study patients were AF-free during 1-year follow-up period after a single procedure based on the novel extensive ablation strategy combining CBA, RFA, and EA-VOM. This strategy for non-PAF may be preferred in terms of maintenance of sinus rhythm, safety even in high-risk patients, and relatively short procedure time.

Novel Insights into Microbial Behavior Gleaned Using Microfluidics.

Microorganisms develop into communities in nearly every environmental niche, which is typically replete with micrometer-scale gaps and features. In each of these habitats, microorganisms adapt to and are affected by their physical environment. Conventional culture methods use glass bottom dishes or millimeter-scale flow cells, which poorly mimic the complexity of natural micrometer-scale environments; therefore, the limitations associated with the creation of microbe-scale environments with granularity hinder the ability to examine their ecological behavior. Microfluidics is a tool that is increasingly being used to study microorganisms because it enables the manipulation of micrometer-scale flows while simultaneously facilitating real-time and live-cell imaging. In this review, we discuss several insights into the behavior of bacteria and fungi that were gained through the adoption of microfluidics to control complex micrometer-scale environments. We also discuss the potential of the increased adoption of this tool.

ILD-GAP Combined with the Charlson Comorbidity Index Score (ILD-GAPC) as a Prognostic Prediction Model in Patients with Interstitial Lung Disease.

Background: The ILD-GAP scoring system has been widely used to predict the prognosis of patients with interstitial lung disease (ILD). The ability of the ILD-GAP scoring system combined with the Charlson Comorbidity Index score (CCIS) (ILD-GAPC) to predict ILD prognosis was investigated. Methods: In ILD patients, including idiopathic pulmonary fibrosis (IPF), idiopathic nonspecific interstitial pneumonia (iNSIP), collagen vascular disease-related interstitial pneumonia (CVD-IP), chronic hypersensitivity pneumonitis (CHP), and unclassifiable ILD (UC-ILD), treated between April 2013 and April 2017, the relationships between baseline clinical parameters, including age, sex, CCIS, ILD diagnosis, pulmonary function test results, and disease outcomes, were retrospectively assessed, and the ability to predict prognosis was compared between the ILD-GAP and ILD-GAPC models, respectively. Results: A total of 185 patients (mean age, 71.9 years), all of whom underwent pulmonary function testing, including percentage predicted diffusion capacity for carbon monoxide, were assessed. ILD diagnosis consisted of IPF in 57 cases, iNSIP and CVD-IP in 117 cases, CHP in 6 cases, and UC-ILD in 5 cases. The ILD-GAPC provided a greater area under the receiver operating characteristic curve (0.758) for predicting 3-year ILD-related events than the ILD-GAP (0.721). In addition, log-rank tests showed that the Kaplan-Meier curves differed significantly among low, middle, and high ILD-GAPC scores (P < 0.001), unlike ILD-GAP scores (P = 0.083). Conclusions: The ILD-GAPC model could provide more accurate information for predicting prognosis in patients with ILD than the ILD-GAP model.

Assessment of diagnostic utility of serum hemeoxygenase-1 measurement for acute exacerbation of interstitial pneumonias.

The present study aimed to evaluate whether serum heme oxygenase (HO)-1 could be a reliable blood biomarker for diagnosing acute exacerbations (AEs) of both idiopathic interstitial pneumonia (IIP) and secondary interstitial pneumonia (SIP). Serum HO-1 levels of newly diagnosed patients with IP were measured, and the relationships between serum HO-1 and other serum biomarkers and high-resolution CT scores, were evaluated. Blood samples were collected from 90 patients with IIP, including 32 having an AE, and 32 with SIP, including 9 having an AE. The patients having an AE had significantly higher HO-1 levels than those not having an AE (35.2 ng/mL vs. 16.4 ng/mL; p < 0.001). On receiver operating characteristics (ROC) curve analysis for serum HO-1 ability to detect an AE, the area under the ROC curve (AUC) was 0.87 in patients with IIPs and 0.86 in those with SIPs. Also, in patients with both IIPs and SIPs, the combination of the serum HO-1 level and the GGO score showed favorable AUCs (IIPs: 0.92, SIPs: 0.83), though HO-1-not-including model (combination of LDH and GGO) also showed acceptable AUCs. Serum HO-1 could be a clinically useful biomarker for the accurate diagnosis of patients with AEs.

Usefulness of the over-the-wire microelectrodes catheter in treatment of ventricular arrhythmia arising from the left ventricular summit.

BACKGROUND: This study was aimed to investigate the efficacy of the over-the-wire (OTW) microelectrodes catheter in coronary venous system (CVS) mapping and treatment of outflow tract ventricular arrhythmia (OTVA) arising from the vicinity of the left ventricular summit (LVS). METHODS: Consecutive 62 patients with idiopathic OTVA in whom the OTW microelectrodes catheter was routinely used for CVS mapping were analyzed. CVS mapping was performed for both main trunk (from great cardiac vein to anterior interventricular vein) and branches including the annular branch or septal branch. RESULTS: The earliest activation site (EAS) was within the CVS in 21 patients. Among them, the EAS was within the main trunk of the CVS in seven (33%) and within the branch of the CVS in 14 (67%) patients. Radiofrequency catheter ablation was started at an anatomically adjacent site to the EAS, which eliminated OTVA in 16 (76%) patients　(the endocardial LVOT in 10 and the aortic sinus of Valsalva in six patients). For the remaining five patients with unsuccessful catheter ablation at an anatomically adjacent site, targeted OTVA was eliminated by catheter ablation at the EAS within the CVS in two patients and by chemical ablation with ethanol injection in one patient, resulting in the overall success rate of 90% (19/21). CONCLUSION: The OTW microelectrodes-guided ablation of OTVA from the vicinity of the LVS was effective. In maximizing the efficacy of ablation, CVS branch mapping is important since the earliest activation was commonly recorded not in the main trunk but within the branch of the CVS.

Comparison of Clinical Features between the High and Low Serum KL-6 Patients with Acute Exacerbation of Interstitial Lung Diseases.

Background: Serum Krebs von den Lungen-6 (KL-6) measurement is widely used to assess disease activity or prognosis in patients with interstitial lung diseases (ILDs). However, the clinical differences between high and low serum KL-6 levels at the time of acute exacerbation (AE) of ILD are not well known. Methods: Clinical parameters including age, sex, Charlson Comorbidity Index score (CCIS), blood biomarkers, high-resolution CT findings, and disease mortality were retrospectively compared between high and low KL-6 (cutoff value: 1000 U/mL) patients at the time of diagnosis of AE of ILDs. Results: Thirty-eight high serum KL-6 and 57 low serum KL-6 patients were included. There was no significant difference in 6-month mortality between them (P = 0.685), whereas serum lactate dehydrogenase was a significant predictor of 6-month mortality in the high serum KL-6 patients (odds ratio (OR): 1.006; 95% confidence interval (CI): 1.003-1.009; P < 0.001), and CCIS (OR: 1.502; 95% CI: 1.242-1.838; P < 0.001) and sex (OR: 5.751; 95% CI: 1.121-105.163; P = 0.033) were significant predictors in low serum KL-6 patients. In addition, the incidences of congestive heart failure, symptomatic chronic pulmonary disease, cerebrovascular disease, and second metastatic solid tumours were significantly higher in nonsurvivors with low serum KL-6 than in other groups (P < 0.05). Conclusions: The clinical features in patients with AEs of ILDs may differ depending on the serum KL-6 level, and clinicopathological examination according to this subtyping guided by the serum KL-6 level is essential.

The Extent of Honeycombing on Computed Tomography Cannot Predict the Treatment Outcome of Patients with Acute Exacerbations of Interstitial Lung Disease.

Background: The purpose of this retrospective study was to clarify whether the presence of honeycombing on computed tomography (CT) can affect the prognosis of patients with acute exacerbations (AEs) of interstitial lung diseases (ILDs). Methods: Clinical parameters including age, sex, Charlson Comorbidity Index Score (CCIS), blood biomarkers, and 3-month mortality were retrospectively compared between the CT honeycombing present and absent groups at the diagnosis of AEs of ILDs. Results: Ninety-five patients who were on corticosteroid pulse therapy were assessed. Though log-rank tests showed that Kaplan-Meier survival curves of the high and low ground-glass opacity (GGO) score groups differed significantly in 3-month mortality in patients with AEs of idiopathic ILDs (P = 0.007) and overall patients (P = 0.045), there was no significant difference between the CT honeycombing present and absent groups in patients with AEs of idiopathic ILDs (P = 0.472) and AEs of secondary ILDs (P = 0.905), as well as of overall patients (P = 0.600). In addition, whereas CCIS (OR, 1.436; 95% CI, 1.156-1.842; P < 0.001) was a significant predictor of 3-month mortality in the CT honeycombing absent group, serum LDH (OR, 1.005; 95% CI, 1.002-1.007; P = 0.001) was a significant predictor in the CT honeycombing present group. Conclusions: The clinical features of patients with or without honeycombing may differ due to the difference in prognostic factors, but these groups were found to have similar prognoses 3 months after AE onset, and clinicopathological examinations according to these groups are essential.

Heme Oxygenase-1 in Patients With Interstitial Lung Disease: A Review of the Clinical Evidence.

The clinical course and rate of progression of interstitial lung disease (ILD) are extremely variable among patients. For the purpose of monitoring disease activity, ILD diagnosis, and predicting disease prognosis, there are various biomarkers, including symptoms, physiological, radiological, and pathological findings, and peripheral blood and bronchoalveolar lavage fluid results. Of these, blood biomarkers such as sialylated carbohydrate antigen, surfactant proteins-A and -D, CC-chemokine ligand 18, matrix metalloprotease-1 and -7, CA19-9, and CA125 have been previously proposed. In the future, heme oxygenase-1 (HO-1) may also become a candidate ILD biomarker; it is a 32-kDa heat shock protein converting heme to carbon monoxide, biliverdin/bilirubin, and free iron to play a role in the pulmonary cytoprotective reaction in response to various stimuli. Recent research suggests that HO-1 can increase in lung tissues of patients with ILD, reflecting anti-inflammatory M2 macrophage activation, and the measurement of HO-1 levels in peripheral blood can be useful for evaluating the severity of lung damage in ILD and for predicting subsequent fibrosis formation.

Serum heme oxygenase-1 measurement is useful for evaluating disease activity and outcomes in patients with acute respiratory distress syndrome and acute exacerbation of interstitial lung disease.

BACKGROUND: Oxidative stress plays an important role in acute lung injury, which is associated with the development and progression of acute respiratory failure. Here, we investigated whether the degree of oxidative stress as indicated by serum heme oxygenase-1 (HO-1) is clinically useful for predicting prognosis among the patients with acute respiratory distress syndrome (ARDS) and acute exacerbation of interstitial lung disease (AE-ILD). METHODS: Serum HO-1 levels of newly diagnosed or untreated ARDS and AE-ILD patients were measured at diagnosis. Relationships between serum HO-1 and other clinical parameters and 1 and 3-month mortality were evaluated. RESULTS: Fifty-five patients including 22 of ARDS and 33 of AE-ILD were assessed. Serum HO-1 level at diagnosis was significantly higher in ARDS patients than AE-ILD patients (87.8 ± 60.0 ng/mL vs. 52.5 ± 36.3 ng/mL, P <  0.001). Serum HO-1 correlated with serum total bilirubin (R = 0.454, P <  0.001) and serum LDH (R = 0.500, P <  0.001). In both patients with ARDS and AE-ILDs, serum HO-1 level tended to decrease from diagnosis to 2 weeks after diagnosis, however, did not normalized. Composite parameters including serum HO-1, age, sex, and partial pressure of oxygen in arterial blood/fraction of inspired oxygen (P/F) ratio for prediction of 3-month mortality showed a higher AUC (ARDS: 0.925, AE-ILDs: 0.892) than did AUCs of a single predictor or combination of two or three predictors. CONCLUSION: Oxidative stress assessed by serum HO-1 is persistently high among enrolled patients for 2 weeks after diagnosis. Also, serum HO-1 levels at the diagnosis combined with age, sex, and P/F ratio could be clinically useful for predicting 3-month mortality in both ARDS and AE-ILD patients.

Competence-Stimulating-Peptide-Dependent Localized Cell Death and Extracellular DNA Production in Streptococcus mutans Biofilms.

Extracellular DNA (eDNA) is a biofilm component that contributes to the formation and structural stability of biofilms. Streptococcus mutans, a major cariogenic bacterium, induces eDNA-dependent biofilm formation under specific conditions. Since cell death can result in the release and accumulation of DNA, the dead cells in biofilms are a source of eDNA. However, it remains unknown how eDNA is released from dead cells and is localized within S. mutans biofilms. We focused on cell death induced by the extracellular signaling peptide called competence-stimulating peptide (CSP). We demonstrate that nucleic acid release into the extracellular environment occurs in a subpopulation of dead cells. eDNA production induced by CSP was highly dependent on the lytF gene, which encodes an autolysin. Although lytF expression was induced bimodally by CSP, lytF-expressing cells further divided into surviving cells and eDNA-producing dead cells. Moreover, we found that lytF-expressing cells were abundant near the bottom of the biofilm, even when all cells in the biofilm received the CSP signal. Dead cells and eDNA were also abundantly present near the bottom of the biofilm. The number of lytF-expressing cells in biofilms was significantly higher than that in planktonic cultures, which suggests that adhesion to the substratum surface is important for the induction of lytF expression. The deletion of lytF resulted in reduced adherence to a polystyrene surface. These results suggest that lytF expression and eDNA production induced near the bottom of the biofilm contribute to a firmly attached and structurally stable biofilm.IMPORTANCE Bacterial communities encased by self-produced extracellular polymeric substances (EPSs), known as biofilms, have a wide influence on human health and environmental problems. The importance of biofilm research has increased, as biofilms are the preferred bacterial lifestyle in nature. Furthermore, in recent years it has been noted that the contribution of phenotypic heterogeneity within biofilms requires analysis at the single-cell or subpopulation level to understand bacterial life strategies. In Streptococcus mutans, a cariogenic bacterium, extracellular DNA (eDNA) contributes to biofilm formation. However, it remains unclear how and where the cells produce eDNA within the biofilm. We focused on LytF, an autolysin that is induced by extracellular peptide signals. We used single-cell level imaging techniques to analyze lytF expression in the biofilm population. Here, we show that S. mutans generates eDNA by inducing lytF expression near the bottom of the biofilm, thereby enhancing biofilm adhesion and structural stability.