The Third Man: DNA sensing as espionage in pulmonary vascular health and disease.

For as long as nucleic acids have been utilized to vertically and horizontally transfer genetic material, living organisms have had to develop methods of recognizing cytosolic DNA as either pathogenic (microbial invasion) or physiologic (mitosis and cellular proliferation). Derangement in key signaling molecules involved in these pathways of DNA sensing result in a family of diseases labeled interferonopathies. An interferonopathy, characterized by constitutive expression of type I interferons, ultimately manifests as severe autoimmune disease at a young age. Afflicted patients present with a constellation of immune-mediated conditions, including primary lung manifestations such as pulmonary fibrosis and pulmonary hypertension. The latter condition is especially interesting in light of the known role that DNA damage plays in a variety of types of inherited and induced pulmonary hypertension, with free DNA detection elevated in the circulation of affected individuals. While little is known regarding the role of cytosolic DNA sensing in development of pulmonary vascular disease, exciting new research in the related fields of immunology and oncology potentially sheds light on future areas of fruitful exploration. As such, the goal of this review is to summarize the state of the field of nucleic acid sensing, extrapolating common shared pathways that parallel our knowledge of pulmonary hypertension, in a molecular and cell-specific manner. Principles of DNA sensing related to known pulmonary injury inducing stimuli are also evaluated, in addition to potential therapeutic targets. Finally, future directions in pulmonary hypertension research and treatments will be briefly discussed.

Optimizing diagnostic biomarkers of iron deficiency anemia in community-dwelling Indian women and preschool children.

The detection of iron deficiency anemia is challenged by the paucity of diagnostic tests demonstrating high sensitivity and specificity. Using two biomarkers, zinc-protoporphyrin/heme and hepcidin, we established the diagnostic cut-off values for iron deficiency anemia in preschool children and women. We randomly selected non-anemic individuals (n=190; women=90, children=100) and individuals with iron deficiency anemia (n=200; women=100, children=100) from a preexisting cohort of healthy preschool children and their mothers. The diagnostic performance of these biomarkers was estimated by analyzing receiver operating characteristic curves. Diagnostic cut-offs with a high predictive value for iron deficiency anemia were selected. Median zinc-protoporphyrin/heme and hepcidin values in non-anemic children were 49 µmol/mol heme and 42 ng/mL, respectively, and in non-anemic women these values were 66 µmol/mol heme and 17.7ng/mL, respectively. Children and women with iron deficiency anemia had higher zinc-protoporphyrin/heme ratios (children=151 µmol/mol heme and women=155 µmol/mol heme) and lower hepcidin levels (children=1.2ng/mL and women=0.6ng/mL). A zinc-protoporphyrin/heme ratio cut-off >90 µmole/mole heme in children and >107 µmole/mole heme in women was associated with a high diagnostic likelihood for iron deficiency anemia (children, likelihood ratio=20.2: women, likelihood ratio=10.8). Hepcidin cut-off values of ≤6.8ng/mL in children and ≤4.5ng/mL in women were associated with a high diagnostic likelihood for iron deficiency anemia (children, likelihood ratio=14.3: women, likelihood ratio=16.2). The reference ranges and cut-off values identified in this study provide clinicians with guidance for applying these tests to detect iron deficiency anemia. Erythrocyte zinc-protoporphyrin/heme ratio is a valid point-of-care biomarker to diagnose iron deficiency anemia.

Influence of Clinical Factors and Exclusion Criteria on Mortality in ARDS Observational Studies and Randomized Controlled Trials.

ARDS has a high mortality in the acute setting, with long-term disability among disease survivors. In 1967, David Ashbaugh and colleagues first described the clinical features of ARDS, which were notably similar to the infantile respiratory distress syndrome. Half a century later, ARDS remains underrecognized and is associated with high mortality rates. Valuable insights from observational studies fail to demonstrate a mortality benefit in randomized controlled trials (RCTs). In the absence of a pharmacologic cure, supportive ventilator strategies limit rather than treat the ongoing lung injury. Interestingly, ARDS has higher mortality rates in observational studies compared to RCTs. Comparing mortality rates between ARDS studies and trials is problematic, partly due to varying time-points at which mortality is reported. Discerning the true mortality attributable to ARDS is also difficult. The diagnostic criteria for ARDS are mainly clinical and lack the objectivity of a laboratory test or biomarker. Nonetheless, these factors are common to both studies and trials, and fail to explain the higher mortality rate of ARDS observational studies. Disease heterogeneity and complex patient characteristics can also confound mortality estimation in ARDS. We therefore examined patient and trial factors that could influence mortality outcomes in ARDS observational studies and RCTs. Unlike RCTs, observational studies include ARDS subjects with severe comorbidities and those requesting limited care. Less stringent selection criteria could thereby contribute to high mortality rates in ARDS observational studies. In contrast, exclusion criteria in RCTs meticulously scrutinize patient characteristics, confining the type and number of eligible subjects. As a result, the task of identifying, consenting, and randomizing eligible patients within the enrollment window is challenging, further decreasing the number of subjects enrolled. Moreover, ARDS RCTs strictly adhere to lung-protective strategies, while ARDS observational studies continually demonstrate variable compliance. This review highlights the impact of patient- and trial-related factors on influencing mortality rates in ARDS observational studies and RCTs.

Transesophageal approach to lung, adrenal biopsy and fiducial placement using endoscopic ultrasonography (EUS): An interventional pulmonology experience. Initial experience of the UCSF-FRETOC (fresno tracheobronchial & oesophageal center) study group.

BACKGROUND: Routine lung cancer surveillance has resulted in early detection of pulmonary nodules and masses. Combined endobronchial ultrasound (EBUS) and trans-esophageal endoscopic ultrasound (EUS) are approved methods for sampling lymph nodes or masses. Furthermore, EUS allows for adrenal sampling as part of staging, and can assist with fiducial placement for stereotactic body radiation therapy (SBRT). OBJECTIVES: Promote use of EUS by interventional pulmonologists in the United States when diagnosing and staging lung cancer or when placing fiducials. METHODS: All patients undergoing EUS and/or EBUS were serially entered into a prospectively maintained database. Only patients undergoing EUS guided lung and/or adrenal biopsy and/or fiducial placement were selected for analysis. All patients underwent a post-procedure chest radiograph and were followed outpatient. RESULTS: 20 of 39 patients underwent sampling of a suspicious lung mass. An adequate sample was obtained in 19 of 20 patients. In all 19 patients a definitive diagnosis was achieved (95%). In all 13 patients who underwent adrenal sampling, presence or absence of metastasis was conclusively established. 6 patients successfully underwent fiducial placement. In all 39 patients, no major procedure related complications were noted for a period of 30 days. One patient had a small pneumothorax that resolved spontaneously. CONCLUSIONS: EUS can be safely performed by a trained interventional pulmonologist for the diagnosis of lung, adrenal masses and placement of fiducials. We think that interventional pulmonologists in the United States involved in lung cancer staging should receive training in EUS techniques.

Lymphangioleiomyomatosis: an explosive presentation of a rare disease.

Lymphangioleiomyomatosis (LAM) is a rare cystic lung disease, commonly affecting women in the reproductive age group. Exacerbation of pre-existing disease is common during pregnancy likely due to the up-regulation of estrogen and progesterone receptors present within the proliferating smooth muscle cells. This case highlights a dramatic presentation of LAM for the first time in pregnancy, its rapid progression during gestation, and a partial resolution with delivery. The unusual radiographic imaging in this patient, lacked the characteristic cystic lesions commonly associated with LAM, but instead demonstrated a dense interstitial pattern with micronodular expansion of the interlobular septa suggesting severe lymphatic obstruction.

The Successful Use of Extracorporeal Membrane Oxygenation in Systemic Lupus Erythematosus-Induced Diffuse Alveolar Haemorrhage.

Diffuse alveolar haemorrhage (DAH) is a catastrophic pulmonary complication of systemic lupus erythematosus. It can result in refractory hypoxaemia despite mechanical ventilation. Increasing lung compliance and worsening pulmonary hypertension can potentiate cardiogenic shock from acute right ventricular failure. In such patients with cardiopulmonary collapse, veno-arterial (V-A) ECMO maybe a viable option that can provide the required haemodynamic support. However, the use of V-A ECMO in such patients is limited due to an associated increased risk of bleeding. Our case report describes the successful use of V-A ECMO without the use of systemic anticoagulation in a patient with DAH. Despite the absence of systemic anticoagulation, no thrombotic complications within the circuit were noted. LEARNING POINTS: Diffuse alveolar haemorrhage (DAH) complicating systemic lupus erythematous can present dramatically with sudden cardiopulmonary collapse.Extracorporeal membrane oxygenation (ECMO) can provide temporary haemodynamic support until conventional medical therapy can take effect.Despite the historical increased bleeding risk associated with ECMO, it can be safely used in patients with DAH to provide time for underlying organ recovery.

MAPK signaling cascades mediate distinct glucocorticoid resistance mechanisms in pediatric leukemia.

The outcome for pediatric acute lymphoblastic leukemia (ALL) patients who relapse is dismal. A hallmark of relapsed disease is acquired resistance to multiple chemotherapeutic agents, particularly glucocorticoids. In this study, we performed a genome-scale short hairpin RNA screen to identify mediators of prednisolone sensitivity in ALL cell lines. The incorporation of these data with an integrated analysis of relapse-specific genetic and epigenetic changes allowed us to identify the mitogen-activated protein kinase (MAPK) pathway as a mediator of prednisolone resistance in pediatric ALL. We show that knockdown of the specific MAPK pathway members MEK2 and MEK4 increased sensitivity to prednisolone through distinct mechanisms. MEK4 knockdown increased sensitivity specifically to prednisolone by increasing the levels of the glucocorticoid receptor. MEK2 knockdown increased sensitivity to all chemotherapy agents tested by increasing the levels of p53. Furthermore, we demonstrate that inhibition of MEK1/2 with trametinib increased sensitivity of ALL cells and primary samples to chemotherapy in vitro and in vivo. To confirm a role for MAPK signaling in patients with relapsed ALL, we measured the activation of the MEK1/2 target ERK in matched diagnosis-relapse primary samples and observed increased phosphorylated ERK levels at relapse. Furthermore, relapse samples have an enhanced response to MEK inhibition compared to matched diagnosis samples in xenograft models. Together, our data indicate that inhibition of the MAPK pathway increases chemosensitivity to glucocorticoids and possibly other agents and that the MAPK pathway is an attractive target for prevention and/or treatment of relapsed disease.

Wnt inhibition leads to improved chemosensitivity in paediatric acute lymphoblastic leukaemia.

While childhood acute lymphoblastic leukaemia (ALL) is now highly curable, the dismal prognosis for children who relapse warrants novel therapeutic approaches. Previously, using an integrated genomic analysis of matched diagnosis-relapse paired samples, we identified overactivation of the Wnt pathway as a possible mechanism of recurrence. To validate these findings and document whether Wnt inhibition may sensitize cells to chemotherapy, we analysed the expression of activated ß-catenin (and its downstream target BIRC5) using multiparameter phosphoflow cytometry and tested the efficacy of a recently developed Wnt inhibitor, iCRT14, in ALL cell lines and patient samples. We observed increased activation of ß-catenin at relapse in 6/10 patients. Furthermore, treatment of leukaemic cell lines with iCRT14 led to significant downregulation of Wnt target genes and combination with traditional chemotherapeutic drugs resulted in a synergistic decrease in viability as well as a significant increase in apoptotic cell death. Finally, pre-treatment of purified blasts from patients with relapsed leukaemia with the Wnt inhibitor followed by exposure to prednisolone, restored chemosensitivity in these cells. Our results demonstrate that overactivation of the Wnt pathway may contribute to chemoresistance in relapsed childhood ALL and that Wnt-inhibition may be a promising therapeutic approach.