Publications by authors named "Philip L Ballard"

65 Publications

Blood metabolomics in infants enrolled in a dose escalation pilot trial of budesonide in surfactant.

Pediatr Res 2021 Jan 19. Epub 2021 Jan 19.

Pediatrics, Oregon Health & Science University, Portland, OR, USA.

Background: The pathogenesis of BPD includes inflammation and oxidative stress in the immature lung. Corticosteroids improve respiratory status and outcome, but the optimal treatment regimen for benefit with low systemic effects is uncertain.

Methods: In a pilot dose escalation trial, we administered ≤5 daily doses of budesonide in surfactant to 24 intubated premature infants (Steroid And Surfactant in ELGANs (SASSIE)). Untargeted metabolomics was performed on dried blood spots using UPLC-MS/MS. Tracheal aspirate IL-8 concentration was determined as a measure of lung inflammation.

Results: Metabolomics data for 829 biochemicals were obtained on 121 blood samples over 96 h from 23 infants receiving 0.025, 0.05, or 0.1 mg budesonide/kg. Ninety metabolites were increased or decreased in a time- and dose-dependent manner at q ≤ 0.1 with overrepresentation in lipid and amino acid super pathways. Different dose response patterns occurred, with negative regulation associated with highest sensitivity to budesonide. Baseline levels of 22 regulated biochemicals correlated with lung inflammation (IL-8), with highest significance for sphingosine and thiamin.

Conclusions: Numerous metabolic pathways are regulated in a dose-dependent manner by glucocorticoids, which apparently act via distinct mechanisms that impact dose sensitivity. The findings identify candidate blood biochemicals as biomarkers of lung inflammation and systemic responses to corticosteroids.

Impact: Treatment of premature infants in respiratory failure with 0.1 mg/kg intra-tracheal budesonide in surfactant alters levels of ~11% of detected blood biochemicals in discrete time- and dose-dependent patterns. A subset of glucocorticoid-regulated biochemicals is associated with lung inflammatory status as assessed by lung fluid cytokine concentration. Lower doses of budesonide in surfactant than currently used may provide adequate anti-inflammatory responses in the lung with fewer systemic effects, improving the benefit:risk ratio.
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http://dx.doi.org/10.1038/s41390-020-01343-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7814527PMC
January 2021

Composition and origin of lung fluid proteome in premature infants and relationship to respiratory outcome.

PLoS One 2020 10;15(12):e0243168. Epub 2020 Dec 10.

Department of Chemistry and Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America.

Background: Infants born at extremely low gestational age are at high risk for bronchopulmonary dysplasia and continuing lung disease. There are no early clinical biomarkers for pulmonary outcome and limited therapeutic interventions.

Objectives: We performed global proteomics of premature infant tracheal aspirate (TA) and plasma to determine the composition and source of lung fluid proteins and to identify potential biomarkers of respiratory outcome.

Methods: TA samples were collected from intubated infants in the TOLSURF cohort before and after nitric oxide treatment, and plasma was collected from NO CLD infants. Protein abundance was assayed by HPLC/tandem mass spectrometry and Protein Prospector software. mRNA abundance in mid-gestation fetal lung was assessed by RNA sequencing. Pulmonary morbidity was defined as a need for ventilatory support at term and during the first year.

Results: Abundant TA proteins included albumin, hemoglobin, and actin-related proteins. 96 of 137 detected plasma proteins were present in TA (r = 0.69, p<0.00001). Based on lung RNAseq data, ~88% of detected TA proteins in injured infant lung are derived at least in part from lung epithelium with overrepresentation in categories of cell membrane/secretion and stress/inflammation. Comparing 37 infants at study enrollment (7-14 days) who did or did not develop persistent pulmonary morbidity, candidate biomarkers of both lung (eg., annexin A5) and plasma (eg., vitamin D-binding protein) origin were identified. Notably, levels of free hemoglobin were 2.9-fold (p = 0.03) higher in infants with pulmonary morbidity. In time course studies, hemoglobin decreased markedly in most infants after enrollment coincident with initiation of inhaled nitric oxide treatment.

Conclusions: We conclude that both lung epithelium and plasma contribute to the lung fluid proteome in premature infants with lung injury. Early postnatal elevation of free hemoglobin and heme, which are both pro-oxidants, may contribute to persistent lung disease by depleting nitric oxide and increasing oxidative/nitrative stress.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0243168PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7728257PMC
January 2021

Human Fetal Tissue Regulation. Impact on Pediatric and Adult Respiratory-related Research.

Ann Am Thorac Soc 2021 02;18(2):204-208

Medicine/Pulmonary and Critical Care Division, University of California San Francisco, San Francisco, California.

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http://dx.doi.org/10.1513/AnnalsATS.202005-460PSDOI Listing
February 2021

Dose-escalation trial of budesonide in surfactant for prevention of bronchopulmonary dysplasia in extremely low gestational age high-risk newborns (SASSIE).

Pediatr Res 2020 10 1;88(4):629-636. Epub 2020 Feb 1.

Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA.

Background: Initial trials of lung-targeted budesonide (0.25 mg/kg) in surfactant to prevent bronchopulmonary dysplasia (BPD) in premature infants have shown benefit; however, the optimal safe dose is unknown.

Methods: Dose-escalation study of budesonide (0.025, 0.05, 0.10 mg/kg) in calfactatant in extremely low gestational age neonates (ELGANs) requiring intubation at 3-14 days. Tracheal aspirate (TA) cytokines, blood budesonide concentrations, and untargeted blood metabolomics were measured. Outcomes were compared with matched infants receiving surfactant in the Trial Of Late SURFactant (TOLSURF).

Results: Twenty-four infants with mean gestational age 25.0 weeks and 743 g birth weight requiring mechanical ventilation were enrolled at mean age 6 days. Budesonide was detected in the blood of all infants with a half-life of 3.4 h. Of 11 infants with elevated TA cytokine levels at baseline, treatment was associated with sustained decrease (mean 65%) at all three dosing levels. There were time- and dose-dependent decreases in blood cortisol concentrations and changes in total blood metabolites. Respiratory outcomes did not differ from the historic controls.

Conclusions: Budesonide/surfactant had no clinical respiratory benefit at any dosing levels for intubated ELGANs. One-tenth the dose used in previous trials had minimal systemic metabolic effects and appeared effective for lung-targeted anti-inflammatory action.
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http://dx.doi.org/10.1038/s41390-020-0792-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7223897PMC
October 2020

Optimizing antenatal corticosteroid therapy for improving outcome of premature infants.

Pediatr Res 2019 11 14;86(5):556-557. Epub 2019 Aug 14.

University of California San Francisco, 513 Parnassus Avenue, HSE 1421, San Francisco, CA, 94194, USA.

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http://dx.doi.org/10.1038/s41390-019-0538-xDOI Listing
November 2019

Development and validation of an assay for quantifying budesonide in dried blood spots collected from extremely low gestational age neonates.

J Pharm Biomed Anal 2019 Apr 29;167:7-14. Epub 2019 Jan 29.

Center for Human Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, United States; Department of Pathology, School of Medicine, University of Utah, Salt Lake City, Utah, United States.

Budesonide is a potential therapeutic option for the prevention of bronchopulmonary dysplasia in mechanically ventilated premature neonates. The dose and concentrations of budesonide that drive effective prophylaxis are unknown, due in part to the difficulty in obtaining serial blood samples from this fragile population. Of primary concern is the limited total blood volume available for collection for the purposes of a pharmacokinetic study. Dried blood spots (DBS), which require the collection of <200 μL whole blood to fill an entire card, are an attractive low-blood volume alternative to traditional venipuncture sampling. We describe a simple and sensitive method for determining budesonide concentrations in DBS using an ultra-high-performance liquid chromatography - tandem mass spectrometry assay. Budesonide was liberated from a single 6 mm punch using a basified methyl tert-butyl ether extraction procedure. The assay was determined to be accurate and precise in the dynamic range of 1 to 50 ng/mL. The validated assay was then successfully applied to DBS collected as part of a multi-center, dose-escalation study of budesonide administered in surfactant via intra-tracheal instillation to premature neonates between 23 and 28 weeks gestational age. These findings show that DBS are a useful technique for collecting pharmacokinetic samples in premature neonates and other pediatric populations.
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http://dx.doi.org/10.1016/j.jpba.2019.01.048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7233423PMC
April 2019

Correction: Genetic variation in CRHR1 is associated with short-term respiratory response to corticosteroids in preterm infants at risk for bronchopulmonary dysplasia.

Pediatr Res 2019 Apr;85(5):731

Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA.

In the original version of this article, the Supplementary Information file contained incorrect reference numbers. 'Supplemental Table S1' has now been replaced with the corrected version, in which the correct reference numbers are cited. The authors would like to apologise for this error.
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http://dx.doi.org/10.1038/s41390-019-0314-yDOI Listing
April 2019

Genetic variation in CRHR1 is associated with short-term respiratory response to corticosteroids in preterm infants at risk for bronchopulmonary dysplasia.

Pediatr Res 2019 04 22;85(5):625-633. Epub 2018 Nov 22.

Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA.

Background: Bronchopulmonary dysplasia (BPD) is an orphan disease and advances in prevention and treatment are lacking. The clinical efficacy of systemic corticosteroid therapy to reduce the severity of lung disease and BPD is highly variable. Our objective was to assess whether candidate SNPs in corticosteroid metabolism and response genes are associated with short-term phenotypic response to systemic corticosteroids in infants at high risk for BPD.

Methods: Pharmacogenetic analysis of data from a large randomized controlled trial (TOLSURF) in infants treated with dexamethasone or hydrocortisone using multivariate linear regression. The primary outcome was a change in respiratory severity score (RSS, mean airway pressure x FiO2) at day 7 of corticosteroid treatment.

Results: rs7225082 in the intron of CRHR1 is significantly associated with the magnitude of decrease in RSS 7 days after starting treatment with systemic corticosteroid (meta-analysis P = 2.8 × 10). Each T allele at rs7225082 is associated with a smaller absolute change in RSS at day 7, i.e., less response to systemic corticosteroids.

Conclusions: Genetic variability is associated with corticosteroid responsiveness with regard to respiratory status in preterm infants. Identification of genetic markers of corticosteroid responsiveness may allow for therapeutic individualization, with the goal of optimizing the risk-to-benefit ratio for an individual child.
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http://dx.doi.org/10.1038/s41390-018-0235-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6532775PMC
April 2019

Exome sequencing identifies gene variants and networks associated with extreme respiratory outcomes following preterm birth.

BMC Genet 2018 10 20;19(1):94. Epub 2018 Oct 20.

Department of Pediatrics, University of Rochester, Rochester, NY, USA.

Background: Previous studies have identified genetic variants associated with bronchopulmonary dysplasia (BPD) in extremely preterm infants. However, findings with genome-wide significance have been rare, and not replicated. We hypothesized that whole exome sequencing (WES) of premature subjects with extremely divergent phenotypic outcomes could facilitate the identification of genetic variants or gene networks contributing disease risk.

Results: The Prematurity and Respiratory Outcomes Program (PROP) recruited a cohort of > 765 extremely preterm infants for the identification of markers of respiratory morbidity. We completed WES on 146 PROP subjects (85 affected, 61 unaffected) representing extreme phenotypes of early respiratory morbidity. We tested for association between disease status and individual common variants, screened for rare variants exclusive to either affected or unaffected subjects, and tested the combined association of variants across gene loci. Pathway analysis was performed and disease-related expression patterns were assessed. Marginal association with BPD was observed for numerous common and rare variants. We identified 345 genes with variants unique to BPD-affected preterm subjects, and 292 genes with variants unique to our unaffected preterm subjects. Of these unique variants, 28 (19 in the affected cohort and 9 in unaffected cohort) replicate a prior WES study of BPD-associated variants. Pathway analysis of sets of variants, informed by disease-related gene expression, implicated protein kinase A, MAPK and Neuregulin/epidermal growth factor receptor signaling.

Conclusions: We identified novel genes and associated pathways that may play an important role in susceptibility/resilience for the development of lung disease in preterm infants.
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http://dx.doi.org/10.1186/s12863-018-0679-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6195962PMC
October 2018

Surfactant status and respiratory outcome in premature infants receiving late surfactant treatment.

Pediatr Res 2019 02 15;85(3):305-311. Epub 2018 Aug 15.

Department of Pediatrics, University of California, San Francisco, San Francisco, CA, USA.

Background: Many premature infants with respiratory failure are deficient in surfactant, but the relationship to occurrence of bronchopulmonary dysplasia (BPD) is uncertain.

Methods: Tracheal aspirates were collected from 209 treated and control infants enrolled at 7-14 days in the Trial of Late Surfactant. The content of phospholipid, surfactant protein B, and total protein were determined in large aggregate (active) surfactant.

Results: At 24 h, surfactant treatment transiently increased surfactant protein B content (70%, p < 0.01), but did not affect recovered airway surfactant or total protein/phospholipid. The level of recovered surfactant during dosing was directly associated with content of surfactant protein B (r = 0.50, p < 0.00001) and inversely related to total protein (r = 0.39, p < 0.0001). For all infants, occurrence of BPD was associated with lower levels of recovered large aggregate surfactant, higher protein content, and lower SP-B levels. Tracheal aspirates with lower amounts of recovered surfactant had an increased proportion of small vesicle (inactive) surfactant.

Conclusions: We conclude that many intubated premature infants are deficient in active surfactant, in part due to increased intra-alveolar metabolism, low SP-B content, and protein inhibition, and that the severity of this deficit is predictive of BPD. Late surfactant treatment at the frequency used did not provide a sustained increase in airway surfactant.
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http://dx.doi.org/10.1038/s41390-018-0144-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6377352PMC
February 2019

Ancestry and genetic associations with bronchopulmonary dysplasia in preterm infants.

Am J Physiol Lung Cell Mol Physiol 2018 11 16;315(5):L858-L869. Epub 2018 Aug 16.

Department of Pediatrics, University of California , San Francisco, California.

Bronchopulmonary dysplasia in premature infants is a common and often severe lung disease with long-term sequelae. A genetic component is suspected but not fully defined. We performed an ancestry and genome-wide association study to identify variants, genes, and pathways associated with survival without bronchopulmonary dysplasia in 387 high-risk infants treated with inhaled nitric oxide in the Trial of Late Surfactant study. Global African genetic ancestry was associated with increased survival without bronchopulmonary dysplasia among infants of maternal self-reported Hispanic white race/ethnicity [odds ratio (OR) = 4.5, P = 0.01]. Admixture mapping found suggestive outcome associations with local African ancestry at chromosome bands 18q21 and 10q22 among infants of maternal self-reported African-American race/ethnicity. For all infants, the top individual variant identified was within the intron of NBL1, which is expressed in midtrimester lung and is an antagonist of bone morphogenetic proteins ( rs372271081 , OR = 0.17, P = 7.4 × 10). The protective allele of this variant was significantly associated with lower nitric oxide metabolites in the urine of non-Hispanic white infants ( P = 0.006), supporting a role in the racial differential response to nitric oxide. Interrogating genes upregulated in bronchopulmonary dysplasia lungs indicated association with variants in CCL18, a cytokine associated with fibrosis and interstitial lung disease, and pathway analyses implicated variation in genes involved in immune/inflammatory processes in response to infection and mechanical ventilation. Our results suggest that genetic variation related to lung development, drug metabolism, and immune response contribute to individual and racial/ethnic differences in respiratory outcomes following inhaled nitric oxide treatment of high-risk premature infants.
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http://dx.doi.org/10.1152/ajplung.00073.2018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6295513PMC
November 2018

Reply.

J Pediatr 2018 10 18;201:300-301. Epub 2018 Jul 18.

University of California San Francisco, California.

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http://dx.doi.org/10.1016/j.jpeds.2018.06.039DOI Listing
October 2018

Maternal Black Race and Persistent Wheezing Illness in Former Extremely Low Gestational Age Newborns: Secondary Analysis of a Randomized Trial.

J Pediatr 2018 07 4;198:201-208.e3. Epub 2018 Apr 4.

Department of Pediatrics, UCSF Benioff Children's Hospital, San Francisco, CA. Electronic address:

Objective: To evaluate the relationship between maternal self-reported race/ethnicity and persistent wheezing illness in former high-risk, extremely low gestational age newborns, and to quantify the contribution of socioeconomic, environmental, and biological factors on this relationship.

Study Design: We assessed persistent wheezing illness determined at 18-24 months corrected (for prematurity) age in survivors of a randomized trial. Parents/caregivers were surveyed for wheeze and inhaled asthma medication use quarterly to 12 months, and at 18 and 24 months. We used multivariable analysis to evaluate the relationship of maternal race to persistent wheezing illness, and identified mediators for this relationship via formal mediation analysis.

Results: Of 420 infants (25.2 ± 1.2 weeks of gestation and 714 ± 166 g at birth, 57% male, 34% maternal black race), 189 (45%) had persistent wheezing illness. After adjustment for gestational age, birth weight, and sex, infants of black mothers had increased odds of persistent wheeze compared with infants of nonblack mothers (OR = 2.9, 95% CI 1.9, 4.5). Only bronchopulmonary dysplasia, breast milk diet, and public insurance status were identified as mediators. In this model, the direct effect of race accounted for 69% of the relationship between maternal race and persistent wheeze, whereas breast milk diet, public insurance status, and bronchopulmonary dysplasia accounted for 8%, 12%, and 10%, respectively.

Conclusions: Among former high-risk extremely low gestational age newborns, infants of black mothers have increased odds of developing persistent wheeze. A substantial proportion of this effect is directly accounted for by race, which may reflect unmeasured environmental influences, and acquired and innate biological differences.

Trial Registration: ClinicalTrials.gov: NCT01022580.
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http://dx.doi.org/10.1016/j.jpeds.2018.02.032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6019148PMC
July 2018

Race Effects of Inhaled Nitric Oxide in Preterm Infants: An Individual Participant Data Meta-Analysis.

J Pediatr 2018 02 11;193:34-39.e2. Epub 2017 Dec 11.

University of California, San Francisco, CA.

Objective: To assess whether inhaled nitric oxide (iNO) improves survival without bronchopulmonary dysplasia (BPD) for preterm African American infants.

Study Design: An individual participant data meta-analysis was conducted, including 3 randomized, placebo-controlled trials that enrolled infants born at  <34 weeks of gestation receiving respiratory support, had at least 15% (or a minimum of 10 infants in each trial arm) of African American race, and used a starting iNO of >5  parts per million with the intention to treat for 7 days minimum. The primary outcome was a composite of death or BPD. Secondary outcomes included death before discharge, postnatal steroid use, gross pulmonary air leak, pulmonary hemorrhage, measures of respiratory support, and duration of hospital stay.

Results: Compared with other races, African American infants had a significant reduction in the composite outcome of death or BPD with iNO treatment: 49% treated vs 63% controls (relative risk, 0.77; 95% CI, 0.65-0.91; P = .003; interaction P = .016). There were no differences between racial groups for death. There was also a significant difference between races (interaction P = .023) of iNO treatment for BPD in survivors, with the greatest effect in African American infants (P = .005). There was no difference between racial groups in the use of postnatal steroids, pulmonary air leak, pulmonary hemorrhage, or other measures of respiratory support.

Conclusion: iNO therapy should be considered for preterm African American infants at high risk for BPD. iNO to prevent BPD in African Americans may represent an example of a racially customized therapy for infants.
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http://dx.doi.org/10.1016/j.jpeds.2017.10.004DOI Listing
February 2018

Commentary on the identity of fibroblast pneumocyte factor: rat vs. human.

Authors:
Philip L Ballard

Pediatr Res 2017 07 31;82(1):4-5. Epub 2017 May 31.

Department of Pediatrics University of California, San Francisco, California.

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http://dx.doi.org/10.1038/pr.2017.85DOI Listing
July 2017

The Randomized, Controlled Trial of Late Surfactant: Effects on Respiratory Outcomes at 1-Year Corrected Age.

J Pediatr 2017 04 16;183:19-25.e2. Epub 2017 Jan 16.

Department of Pediatrics, University of California San Francisco, San Francisco, CA.

Objective: To determine the effects of late surfactant on respiratory outcomes determined at 1-year corrected age in the Trial of Late Surfactant (TOLSURF), which randomized newborns of extremely low gestational age (≤28 weeks' gestational age) ventilated at 7-14 days to late surfactant and inhaled nitric oxide vs inhaled nitric oxide-alone (control).

Study Design: Caregivers were surveyed in a double-blinded manner at 3, 6, 9, and 12 months' corrected age to collect information on respiratory resource use (infant medication use, home support, and hospitalization). Infants were classified for composite outcomes of pulmonary morbidity (no PM, determined in infants with no reported respiratory resource use) and persistent PM (determined in infants with any resource use in ≥3 surveys).

Results: Infants (n = 450, late surfactant n = 217, control n = 233) were 25.3 ± 1.2 weeks' gestation and 713 ± 164 g at birth. In the late surfactant group, fewer infants received home respiratory support than in the control group (35.8% vs 52.9%, relative benefit [RB] 1.28 [95% CI 1.07-1.55]). There was no benefit of late surfactant for No PM vs PM (RB 1.27; 95% CI 0.89-1.81) or no persistent PM vs persistent PM (RB 1.01; 95% CI 0.87-1.17). After adjustment for imbalances in baseline characteristics, relative benefit of late surfactant treatment increased: RB 1.40 (95% CI 0.89-1.80) for no PM and RB 1.24 (95% CI 1.08-1.42) for no persistent PM.

Conclusion: Treatment of newborns of extremely low gestational age with late surfactant in combination with inhaled nitric oxide decreased use of home respiratory support and may decrease persistent pulmonary morbidity.

Trial Registration: ClinicalTrials.gov: NCT01022580.
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http://dx.doi.org/10.1016/j.jpeds.2016.12.059DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5367937PMC
April 2017

Antiinflammatory Effects of Budesonide in Human Fetal Lung.

Am J Respir Cell Mol Biol 2016 11;55(5):623-632

1 Departments of Pediatrics.

Lung inflammation in premature infants contributes to the development of bronchopulmonary dysplasia (BPD), a chronic lung disease with long-term sequelae. Pilot studies administering budesonide suspended in surfactant have found reduced BPD without the apparent adverse effects that occur with systemic dexamethasone therapy. Our objective was to determine budesonide potency, stability, and antiinflammatory effects in human fetal lung. We cultured explants of second-trimester fetal lung with budesonide or dexamethasone and used microscopy, immunoassays, RNA sequencing, liquid chromatography/tandem mass spectrometry, and pulsating bubble surfactometry. Budesonide suppressed secreted chemokines IL-8 and CCL2 (MCP-1) within 4 hours, reaching a 90% decrease at 12 hours, which was fully reversed 72 hours after removal of the steroid. Half-maximal effects occurred at 0.04-0.05 nM, representing a fivefold greater potency than for dexamethasone. Budesonide significantly induced 3.6% and repressed 2.8% of 14,500 sequenced mRNAs by 1.6- to 95-fold, including 119 genes that contribute to the glucocorticoid inflammatory transcriptome; some are known targets of nuclear factor-κB. By global proteomics, 22 secreted inflammatory proteins were hormonally regulated. Two glucocorticoid-regulated genes of interest because of their association with lung disease are CHI3L1 and IL1RL1. Budesonide retained activity in the presence of surfactant and did not alter its surface properties. There was some formation of palmitate-budesonide in lung tissue but no detectable metabolism to inactive 16α-hydroxy prednisolone. We concluded that budesonide is a potent and stable antiinflammatory glucocorticoid in human fetal lung in vitro, supporting a beneficial antiinflammatory response to lung-targeted budesonide:surfactant treatment of infants for the prevention of BPD.
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http://dx.doi.org/10.1165/rcmb.2016-0068OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5105184PMC
November 2016

Early Cumulative Supplemental Oxygen Predicts Bronchopulmonary Dysplasia in High Risk Extremely Low Gestational Age Newborns.

J Pediatr 2016 Oct 26;177:97-102.e2. Epub 2016 Jul 26.

Department of Pediatrics, University of California, San Francisco Benioff Children's Hospital, San Francisco, CA. Electronic address:

Objective: To assess the prognostic accuracy of early cumulative supplemental oxygen (CSO) exposure for prediction of bronchopulmonary dysplasia (BPD) or death, and to evaluate the independent association of CSO with BPD or death.

Study Design: We performed a secondary analysis of the Trial of Late Surfactant, which enrolled 511 infants born at ≤28 weeks gestational age who were mechanically ventilated at 7-14 days of life. Our primary outcome was BPD or death at 36 weeks postmenstrual age, as determined by a physiological oxygen/flow challenge. Average daily supplemental oxygen (fraction of inspired oxygen - 0.21) was calculated. CSO was calculated as the sum of the average daily supplemental oxygen over time periods of interest up to 28 days of age. Area under the receiver operating curve (AUROC) values were generated to evaluate the accuracy of CSO for prediction of BPD or death. The independent relationship between CSO and BPD or death was assessed in multivariate modeling, while adjusting for mean airway pressure.

Results: In the study infants, mean gestational age at birth was 25.2 ± 1.2 weeks and mean birth weight was 700 ± 165 g. The AUROC value for CSO at 14 days was significantly better than that at earlier time points for outcome prediction (OR, 0.70; 95% CI, 0.65-0.74); it did not increase with the addition of later data. In multivariate modeling, a CSO increase of 1 at 14 days increased the odds of BPD or death (OR, 1.7; 95% CI, 1.3-2.2; P < .0001), which corresponds to a 7% higher daily supplemental oxygen value.

Conclusion: In high-risk extremely low gestational age newborns, the predictive accuracy of CSO plateaus at 14 days. CSO is independently associated with BPD or death. This index may identify infants who could benefit from early intervention to prevent BPD.
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http://dx.doi.org/10.1016/j.jpeds.2016.06.079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5037007PMC
October 2016

Expression of human carcinoembryonic antigen-related cell adhesion molecule 6 and alveolar progenitor cells in normal and injured lungs of transgenic mice.

Physiol Rep 2015 Dec 22;3(12). Epub 2015 Dec 22.

Department of Pediatrics, University of California San Francisco, San Francisco, California

Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) is expressed in the epithelium of various primate tissues, including lung airway and alveoli. In human lung, CEACAM6 is developmentally and hormonally regulated, protects surfactant function, has anti-apoptotic activity and is dysregulated in cancers. We hypothesized that alveolar CEACAM6 expression increases in lung injury and promotes cell proliferation during repair. Studies were performed in CEABAC transgenic mice-containing human CEACAM genes. The level of CEACAM6 in adult CEABAC lung was comparable to that in human infants; expression occurred in epithelium of airways and of some alveoli but rarely co-localized with markers of type I or type II cells. Ten days after bleomycin instillation, both the number of CEACAM6(+) cells and immunostaining intensity were elevated in injured lung areas, and there was increased co-localization with type I and II cell markers. To specifically address type II cells, we crossed CEABAC mice with animals expressing EGFP driven by the SP-C promoter. After bleomycin injury, partially flattened, elongated epithelial cells were observed that expressed type I cell markers and were primarily either EGFP(+) or CEACAM6(+). In cell cycle studies, mitosis was greater in CEACAM6(+) non-type II cells versus CEACAM6(+)/EGFP(+) cells. CEACAM6 epithelial expression was also increased after hyperoxic exposure and LPS instillation, suggesting a generalized response to acute lung injuries. We conclude that CEACAM6 expression is comparable in human lung and the CEABAC mouse. CEACAM6 in this model appears to be a marker of a progenitor cell population that contributes to alveolar epithelial cell replenishment after lung injury.
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http://dx.doi.org/10.14814/phy2.12657DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4760449PMC
December 2015

Randomized Trial of Late Surfactant Treatment in Ventilated Preterm Infants Receiving Inhaled Nitric Oxide.

J Pediatr 2016 Jan 21;168:23-29.e4. Epub 2015 Oct 21.

Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA.

Objective: To assess whether late surfactant treatment in extremely low gestational age (GA) newborn infants requiring ventilation at 7-14 days, who often have surfactant deficiency and dysfunction, safely improves survival without bronchopulmonary dysplasia (BPD).

Study Design: Extremely low GA newborn infants (GA ≤28 0/7 weeks) who required mechanical ventilation at 7-14 days were enrolled in a randomized, masked controlled trial at 25 US centers. All infants received inhaled nitric oxide and either surfactant (calfactant/Infasurf) or sham instillation every 1-3 days to a maximum of 5 doses while intubated. The primary outcome was survival at 36 weeks postmenstrual age (PMA) without BPD, as evaluated by physiological oxygen/flow reduction.

Results: A total of 511 infants were enrolled between January 2010 and September 2013. There were no differences between the treated and control groups in mean birth weight (701 ± 164 g), GA (25.2 ± 1.2 weeks), percentage born at GA <26 weeks (70.6%), race, sex, severity of lung disease at enrollment, or comorbidities of prematurity. Survival without BPD did not differ between the treated and control groups at 36 weeks PMA (31.3% vs 31.7%; relative benefit, 0.98; 95% CI, 0.75-1.28; P = .89) or 40 weeks PMA (58.7% vs 54.1%; relative benefit, 1.08; 95% CI, 0.92-1.27; P = .33). There were no between-group differences in serious adverse events, comorbidities of prematurity, or severity of lung disease to 36 weeks.

Conclusion: Late treatment with up to 5 doses of surfactant in ventilated premature infants receiving inhaled nitric oxide was well tolerated, but did not improve survival without BPD at 36 or 40 weeks. Pulmonary and neurodevelopmental assessments are ongoing.

Trial Registration: ClinicalTrials.gov: NCT01022580.
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http://dx.doi.org/10.1016/j.jpeds.2015.09.031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4698022PMC
January 2016

Pharmacokinetics of Budesonide Administered with Surfactant in Premature Lambs: Implications for Neonatal Clinical Trials.

Curr Clin Pharmacol 2016 ;11(1):53-61

295 Chipeta Way, Salt Lake City, UT 84108, USA.

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of premature human infants, which may persist through adulthood. Airway inflammation has been firmly established in the pathogenesis of BPD. Previous studies to reduce airway inflammation with high-dose dexamethasone demonstrated adverse neurological outcomes, despite lower incidences of BPD. Instillation of budesonide and surfactant can facilitate early extubation and reduce the incidence of BPD and death among very low birth weight infants. However, the pharmacokinetics of budesonide and its distribution into the lung and brain are unknown. Therefore, 5 premature lambs were administered 0.25 mg/kg budesonide, with surfactant as the vehicle. Plasma and tissue samples were taken from the lambs for measurement of budesonide, 16α- hydroxy prednisolone, and budesonide palmitate using LC/MS/MS. Peak plasma budesonide concentrations were inversely correlated with the oxygenation index (correlation coefficient of -0.75). plasma budesonide concentrations were extremely low (~10% of expected) for two lambs that had high oxygenation indices and were excluded from further analyses. For the remaining 5 premature lambs, a non-compartmental analysis demonstrated an AUCinf of 148.77 ± 28.16 h*μg/L, half-life of 4.76 ± 1.79 h, and Cmax of 46.17 ± 17.71 µg/L. Using population pharmacokinetic methods, a onecompartment model with exponential residual error and first-order absorption adequately described the data. The apparent clearance and apparent volume of distribution of budesonide were estimated at 6.29 L/h (1.99 L/h/kg) and 29.1 L (9.2 L/kg), respectively. Budesonide and budesonide palmitate, but not 16α-hydroxy prednisolone, were detected in lung tissue. In this study, budesonide and its metabolites were not detected in the brain, which suggests that intratracheal instillation suggests that after local pulmonary deposition, there is no evidence of budesonide accumulation in the central nervous system. Overall, these results show that peak plasma budesonide concentrations are inversely correlated with the oxygenation index and that lung-specific delivery of budesonide avoids accumulation of budesonide in the brain.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5716806PMC
http://dx.doi.org/10.2174/1574884710666150929100210DOI Listing
December 2016

Expression of Carcinoembryonic Cell Adhesion Molecule 6 and Alveolar Epithelial Cell Markers in Lungs of Human Infants with Chronic Lung Disease.

J Histochem Cytochem 2015 12 15;63(12):908-21. Epub 2015 Sep 15.

Department of Pediatrics, University of California, San Francisco, San Francisco, California (AMB, PLB)

The membrane protein carcinoembryonic antigen cell adhesion molecule (CEACAM6) is expressed in the epithelium of various tissues, participating in innate immune defense, cell proliferation and differentiation, with overexpression in gastrointestinal tract, pancreatic and lung tumors. It is developmentally and hormonally regulated in fetal human lung, with an apparent increased production in preterm infants with respiratory failure. To further examine the expression and cell localization of CEACAM6, we performed immunohistochemical and biochemical studies in lung specimens from infants with and without chronic lung disease. CEACAM6 protein and mRNA were increased ~4-fold in lungs from infants with chronic lung disease as compared with controls. By immunostaining, CEACAM6 expression was markedly increased in the lung parenchyma of infants and children with a variety of chronic lung disorders, localizing to hyperplastic epithelial cells with a ~7-fold elevated proliferative rate by PCNA staining. Some of these cells also co-expressed membrane markers of both type I and type II cells, which is not observed in normal postnatal lung, suggesting they are transitional epithelial cells. We suggest that CEACAM6 is both a marker of lung epithelial progenitor cells and a contributor to the proliferative response after injury due to its anti-apoptotic and cell adhesive properties.
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http://dx.doi.org/10.1369/0022155415603768DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4823795PMC
December 2015

Surface film formation in vitro by infant and therapeutic surfactants: role of surfactant protein B.

Pediatr Res 2015 Feb 31;77(2):340-6. Epub 2014 Oct 31.

Department of Pediatrics, University of California, San Francisco, San Francisco, California.

Background: Pulmonary surfactant provides an alveolar surface-active film that is critical for normal lung function. Our objective was to determine in vitro film formation properties of therapeutic and infant surfactants and the influence of surfactant protein (SP)-B content.

Methods: We used a multiwell fluorescent assay measuring maximum phospholipid surface accumulation (Max), phospholipid concentration required for half-maximal film formation (½Max), and time for maximal accumulation (tMax).

Results: Among five therapeutic surfactants, calfactant (highest SP-B content) had film formation values similar to natural surfactant, and addition of SP-B to beractant (lowest SP-B) normalized its Max value. Addition of budesonide to calfactant did not adversely affect film formation. In tracheal aspirates of preterm infants with evolving chronic lung disease, SP-B content correlated with ½Max and tMax values, and SP-B supplementation of SP-B-deficient infant surfactant restored normal film formation. Reconstitution of normal surfactant indicated a role for both SP-B and SP-C in film formation.

Conclusion: Film formation in vitro differs among therapeutic surfactants and is highly dependent on SP-B content in infant surfactant. The results support a critical role of SP-B for promoting surface film formation.
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http://dx.doi.org/10.1038/pr.2014.176DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4391810PMC
February 2015

Inhaled nitric oxide increases urinary nitric oxide metabolites and cyclic guanosine monophosphate in premature infants: relationship to pulmonary outcome.

Am J Perinatol 2015 Feb 26;32(3):225-32. Epub 2014 Jun 26.

Department of Pediatrics, University of California, San Francisco, California.

Objective: Inhaled nitric oxide (iNO) has been tested to prevent bronchopulmonary dysplasia (BPD) in premature infants, however, the role of cyclic guanosine monophosphate (cGMP) is not known. We hypothesized that levels of NO metabolites (NOx) and cGMP in urine, as a noninvasive source for biospecimen collection, would reflect the dose of iNO and relate to pulmonary outcome.

Study Design: Studies were performed on 125 infants who required mechanical ventilation at 7 to 14 days and received 24 days of iNO at 20-2 ppm. A control group of 19 infants did not receive iNO.

Results: In NO-treated infants there was a dose-dependent increase of both NOx and cGMP per creatinine (maximal 3.1- and 2-fold, respectively, at 10-20 ppm iNO) compared with off iNO. NOx and cGMP concentrations at both 2 ppm and off iNO were inversely related to severity of lung disease during the 1st month, and the NOx levels were lower in infants who died or developed BPD at term. NOx was higher in Caucasian compared with other infants at all iNO doses.

Conclusion: Urinary NOx and cGMP are biomarkers of endogenous NO production and lung uptake of iNO, and some levels reflect the severity of lung disease. These results support a role of the NO-cGMP pathway in lung development.
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http://dx.doi.org/10.1055/s-0034-1382255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5032843PMC
February 2015

Claudin-18 deficiency results in alveolar barrier dysfunction and impaired alveologenesis in mice.

Am J Respir Cell Mol Biol 2014 Oct;51(4):550-8

Departments of 1 Medicine and.

Claudins are a family of transmembrane proteins that are required for tight junction formation. Claudin (CLDN)-18.1, the only known lung-specific tight junction protein, is the most abundant claudin in alveolar epithelial type (AT) 1 cells, and is regulated by lung maturational agonists and inflammatory mediators. To determine the function of CLDN18 in the alveolar epithelium, CLDN18 knockout (KO) mice were generated and studied by histological, biochemical, and physiological approaches, in addition to whole-genome microarray. Alveolar epithelial barrier function was assessed after knockdown of CLDN18 in isolated lung cells. CLDN18 levels were measured by quantitative PCR in lung samples from fetal and postnatal human infants. We found that CLDN18 deficiency impaired alveolar epithelial barrier function in vivo and in vitro, with evidence of increased paracellular permeability and architectural distortion at AT1-AT1 cell junctions. Although CLDN18 KO mice were born without evidence of a lung abnormality, histological and gene expression analysis at Postnatal Day 3 and Week 4 identified impaired alveolarization. CLDN18 KO mice also had evidence of postnatal lung injury, including acquired AT1 cell damage. Human fetal lungs at 23-24 weeks gestational age, the highest-risk period for developing bronchopulmonary dysplasia, a disease of impaired alveolarization, had significantly lower CLDN18 expression relative to postnatal lungs. Thus, CLDN18 deficiency results in epithelial barrier dysfunction, injury, and impaired alveolarization in mice. Low expression of CLDN18 in human fetal lungs supports further investigation into a role for this tight junction protein in bronchopulmonary dysplasia.
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http://dx.doi.org/10.1165/rcmb.2013-0456OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4189483PMC
October 2014

Late administration of surfactant replacement therapy increases surfactant protein-B content: a randomized pilot study.

Pediatr Res 2012 Dec 4;72(6):613-9. Epub 2012 Oct 4.

Department of Pediatrics, University of California, San Francisco, San Francisco, California, USA.

Background: Surfactant dysfunction may contribute to the development of bronchopulmonary dysplasia (BPD) in persistently ventilated preterm infants. We conducted a multicenter randomized, blinded, pilot study to assess the safety and efficacy of late administration of doses of a surfactant protein-B (SP-B)-containing surfactant (calfactant) in combination with prolonged inhaled nitric oxide (iNO) in infants ≤1,000 g birth weight (BW).

Methods: We randomized 85 preterm infants ventilated at 7-14 d after birth to receive either late administration of surfactant (up to 5 doses) plus prolonged iNO or iNO alone. Large aggregate surfactant was isolated from daily tracheal aspirates (TAs) for measurement of SP-B content, total protein, and phospholipid (PL).

Results: Late administration of surfactant had minimal acute adverse effects. Clinical status as well as surfactant recovery and SP-B content in tracheal aspirate were transiently improved as compared to the controls; these effects waned after 1 d. The change in SP-B content with surfactant dosing was positively correlated with SP-B levels during treatment (r = 0.50, P = 0.02).

Conclusion: Low SP-B values increased with calfactant administration, but the relationship of this response to SP-B levels suggests that degradation is a contributing mechanism for SP-B deficiency and surfactant dysfunction. We conclude that late therapy with surfactant in combination with iNO is safe and transiently increases surfactant SP-B content, possibly leading to improved short- and long-term respiratory outcomes.
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http://dx.doi.org/10.1038/pr.2012.136DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3548137PMC
December 2012

Distribution and surfactant association of carcinoembryonic cell adhesion molecule 6 in human lung.

Am J Physiol Lung Cell Mol Physiol 2012 Jan 28;302(2):L216-25. Epub 2011 Oct 28.

Department of Pediatrics, University of California San Francisco, San Francisco, California, USA.

Carcinoembryonic cell adhesion molecule 6 (CEACAM6) is a glycosylated, glycophosphatidylinositol-anchored protein expressed in epithelial cells of various primate tissues. It binds gram-negative bacteria and is overexpressed in human cancers. CEACAM6 is associated with lamellar bodies of cultured type II cells of human fetal lung and protects surfactant function in vitro. In this study, we characterized CEACAM6 expression in vivo in human lung. CEACAM6 was present in lung lavage of premature infants at birth and increased progressively in intubated infants with lung disease. Of surfactant-associated CEACAM6, ∼80% was the fully glycosylated, 90-kDa form that contains the glycophosphatidylinositol anchor, and the concentration (3.9% of phospholipid for adult lung) was comparable to that for surfactant proteins (SP)-A/B/C. We examined the affinity of CEACAM6 by purification of surfactant on density gradient centrifugation; concentrations of CEACAM6 and SP-B per phospholipid were unchanged, whereas levels of total protein and SP-A decreased by 60%. CEACAM6 mRNA content decreased progressively from upper trachea to peripheral fetal lung, whereas protein levels were similar in all regions of adult lung, suggesting proximal-to-distal developmental expression in lung epithelium. In adult lung, most type I cells and ∼50% of type II cells were immunopositive. We conclude that CEACAM6 is expressed by alveolar and airway epithelial cells of human lung and is secreted into lung-lining fluid, where fully glycosylated protein binds to surfactant. Production appears to be upregulated during neonatal lung disease, perhaps related to roles of CEACAM6 in surfactant function, cell proliferation, and innate immune defense.
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http://dx.doi.org/10.1152/ajplung.00055.2011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3349363PMC
January 2012

A small-molecule smoothened agonist prevents glucocorticoid-induced neonatal cerebellar injury.

Sci Transl Med 2011 Oct;3(105):105ra104

Division of Neonatology, Department of Pediatrics, University of California, San Francisco (UCSF), San Francisco, CA 94143, USA.

Glucocorticoids are used for treating preterm neonatal infants suffering from life-threatening lung, airway, and cardiovascular conditions. However, several studies have raised concerns about detrimental effects of postnatal glucocorticoid administration on the developing brain leading to cognitive impairment, cerebral palsy, and hypoplasia of the cerebellum, a brain region critical for coordination of movement and higher-order neurological functions. Previously, we showed that glucocorticoids inhibit Sonic hedgehog-Smoothened (Shh-Smo) signaling, the major mitogenic pathway for cerebellar granule neuron precursors. Conversely, activation of Shh-Smo in transgenic mice protects against glucocorticoid-induced neurotoxic effects through induction of the 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) pathway. Here, we show that systemic administration of a small-molecule agonist of the Shh-Smo pathway (SAG) prevented the neurotoxic effects of glucocorticoids. SAG did not interfere with the beneficial effects of glucocorticoids on lung maturation, and despite the known associations of the Shh pathway with neoplasia, we found that transient (1-week-long) SAG treatment of neonatal animals was well tolerated and did not promote tumor formation. These findings suggest that a small-molecule agonist of Smo has potential as a neuroprotective agent in neonates at risk for glucocorticoid-induced neonatal cerebellar injury.
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http://dx.doi.org/10.1126/scitranslmed.3002731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3694585PMC
October 2011

HTII-280, a biomarker specific to the apical plasma membrane of human lung alveolar type II cells.

J Histochem Cytochem 2010 Oct 21;58(10):891-901. Epub 2010 Jun 21.

Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94118, USA.

The pulmonary alveolar epithelium is composed of two morphologically distinct cell types, type I (TI) and type II (TII) cells. Alveolar TII cells synthesize, secrete, and recycle surfactant components; contain ion transporters; and secrete immune effector molecules. In response to alveolar injury, TII cells have the capacity to act as progenitor cells, proliferating and transdifferentiating into TI cells. Although various proteins are associated with TII cells, a plasma membrane marker specific to human TII cells that would be useful for identification in tissue and for isolating this cell type has not been described previously. We devised a strategy to produce a monoclonal antibody (MAb) specific to the apical surface of human TII cells and developed an MAb that appears to be specific for human TII cells. The antibody recognizes a 280- to 300-kDa protein, HTII-280, which has the biochemical characteristics of an integral membrane protein. HTII-280 is detected by week 11 of gestation and is developmentally regulated. HTII-280 is useful for isolating human TII cells with purities and viabilities >95%. HTII-280 is likely to be a useful morphological and biochemical marker of human TII cells that may help to advance our understanding of various lung pathological conditions, including the origin and development of various lung tumors.
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http://dx.doi.org/10.1369/jhc.2010.956433DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2942742PMC
October 2010