David M Hwang

University of Toronto, Toronto, Ontario, Canada

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Publications (100)441.59 Total impact

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    ABSTRACT: Pulmonary infections caused by Pseudomonas aeruginosa are a recalcitrant problem in cystic fibrosis (CF) patients. While the clinical implications and long-term evolutionary patterns of these infections are well studied, we know little about the short-term population dynamics that enable this pathogen to persist despite aggressive antimicrobial therapy. Here, we describe a short-term population genomic analysis of 233 P. aeruginosa isolates collected from 12 sputum specimens obtained over a 1-year period from a single patient. Whole-genome sequencing and antimicrobial susceptibility profiling identified the expansion of two clonal lineages. The first lineage originated from the coalescence of the entire sample less than 3 years before the end of the study and gave rise to a high-diversity ancestral population. The second expansion occurred 2 years later and gave rise to a derived population with a strong signal of positive selection. These events show characteristics consistent with recurrent selective sweeps. While we cannot identify the specific mutations responsible for the origins of the clonal lineages, we find that the majority of mutations occur in loci previously associated with virulence and resistance. Additionally, approximately one-third of all mutations occur in loci that are mutated multiple times, highlighting the importance of parallel pathoadaptation. One such locus is the gene encoding penicillin-binding protein 3, which received three independent mutations. Our functional analysis of these alleles shows that they provide differential fitness benefits dependent on the antibiotic under selection. These data reveal that bacterial populations can undergo extensive and dramatic changes that are not revealed by lower-resolution analyses. Pseudomonas aeruginosa is a bacterial opportunistic pathogen responsible for significant morbidity and mortality in cystic fibrosis (CF) patients. Once it has colonized the lung in CF, it is highly resilient and rarely eradicated. This study presents a deep sampling examination of the fine-scale evolutionary dynamics of P. aeruginosa in the lungs of a chronically infected CF patient. We show that diversity of P. aeruginosa is driven by recurrent clonal emergence and expansion within this patient and identify potential adaptive variants associated with these events. This high-resolution sequencing strategy thus reveals important intraspecies dynamics that explain a clinically important phenomenon not evident at a lower-resolution analysis of community structure. Copyright © 2015 Diaz Caballero et al.
    mBio 09/2015; 6(5). DOI:10.1128/mBio.00981-15 · 6.79 Impact Factor
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    ABSTRACT: The long-term success of lung transplantation is challenged by the development of chronic lung allograft dysfunction (CLAD) and its distinct subtypes of bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). However, the current diagnostic criteria for CLAD subtypes rely on total lung capacity (TLC), which is not always measured during routine post-transplant assessment. Our aim was to investigate the utility of low-dose 3-dimensional computed tomography (CT) lung volumetry for differentiating RAS from BOS. This study was a retrospective evaluation of 63 patients who had developed CLAD after bilateral lung or heart‒lung transplantation between 2006 and 2011, including 44 BOS and 19 RAS cases. Median post-transplant follow-up was 65 months in BOS and 27 months in RAS. The median interval between baseline and the disease-onset time-point for CT volumetry was 11 months in both BOS and RAS. Chronologic changes and diagnostic accuracy of CT lung volume (measured as percent of baseline) were investigated. RAS showed a significant decrease in CT lung volume at disease onset compared with baseline (mean 3,916 ml vs 3,055 ml when excluding opacities, p < 0.0001), whereas BOS showed no significant post-transplant change (mean 4,318 ml vs 4,396 ml, p = 0.214). The area under the receiver operating characteristic curve of CT lung volume for differentiating RAS from BOS was 0.959 (95% confidence interval 0.912 to 1.01, p < 0.0001) and the calculated accuracy was 0.938 at a threshold of 85%. In bilateral lung or heart‒lung transplant patients with CLAD, low-dose CT volumetry is a useful tool to differentiate patients who develop RAS from those who develop BOS. Copyright © 2015 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.
    The Journal of heart and lung transplantation: the official publication of the International Society for Heart Transplantation 08/2015; DOI:10.1016/j.healun.2015.07.005 · 6.65 Impact Factor
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    ABSTRACT: Ex vivo lung perfusion (EVLP) allows normothermic evaluation and treatment of donor lungs not currently acceptable for transplant and improves organ use. Donor lungs undergo a period of cold preservation before (cold ischemic time [CIT]-1) and after (CIT-2) EVLP. We investigated the effect of an extended CIT-2 on lung function after transplantation. Explanted pig lungs, preserved in low-potassium dextran flush (Perfadex) at 4°C for 10 hours, were subjected to 6 hours of EVLP. They were subsequently allocated to 2 groups: short CIT-2 (CIT-2 = 2 hours; n = 5), and long CIT-2 (CIT-2 = 10 hours; n = 5). In a control group (n = 6), explanted lungs were placed in cold static preservation for 24 hours without EVLP. After the total preservation period, the left lung was transplanted in all groups. After 4 hours of reperfusion, oxygenation function, acute lung injury score, inflammatory markers, and cell death pathway markers were similar between short and long CIT-2 groups. Both EVLP groups fared significantly better than the control group in oxygenation function (p < 0.05). The intervention of EVLP improved lung function after transplantation, and this was not affected by a prolonged cold static preservation time after EVLP. These results provide the basis for a practical prolonged lung preservation strategy using a combination of cold and warm preservation techniques, which may improve lung transplantation logistics and outcomes. Copyright © 2015 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.
    The Journal of Heart and Lung Transplantation 06/2015; DOI:10.1016/j.healun.2015.05.017 · 6.65 Impact Factor
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    ABSTRACT: Chronic airway infections caused by Pseudomonas aeruginosa contribute to the progression of pulmonary disease in individuals with cystic fibrosis (CF). In the setting of CF, within-patient adaptation of a P. aeruginosa strain generates phenotypic diversity that can complicate microbiological analysis of patient samples. We investigated within- and between- sample diversity of 34 phenotypes among 235 P. aeruginosa isolates cultured from sputum samples collected from a single CF patient over the span of one year, and assessed colony morphology as a screening tool for predicting phenotypes, including antimicrobial susceptibilities. We identified 15 distinct colony morphotypes that varied significantly in abundance both within and between sputum samples. Substantial within sample phenotypic heterogeneity was also noted in other phenotypes, with morphotypes being unreliable predictors of antimicrobial susceptibility and other phenotypes. Emergence of isolates with reduced susceptibility to β-lactams was observed during periods of clinical therapy with aztreonam. Our findings confirm that the P. aeruginosa population in chronic CF lung infections is highly dynamic, and that intra-sample phenotypic diversity is underestimated if only one or few colonies are analyzed per sample.
    Scientific Reports 06/2015; 5. DOI:10.1038/srep10932 · 5.58 Impact Factor
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    ABSTRACT: Background: Lung cancer in never smokers represents a distinct clinical and molecular entity characterized by frequent actionable driver mutations. Methods: Clinical and demographic data of 503 never smokers with advanced NSCLC were retrieved from patient records in order to characterize treatment outcome, survival, demographics, pathology and molecular profile. Results: There were 203 patients treated with targeted therapy (T-pts) and 300 patients without (NT-pts). Median age at diagnosis in T- and NT-pts was 59.7 & 61.6 yrs, respectively. Most patients in both groups were female (75%), with 49% & 37% Asians among T- and NT-pts, respectively. Most tumors in T-pts (193/203, 95%) had a single mutation (MUT): EGFR 167/193 (87%), ALK 23/193 (12%), and HER-2 3/193 (1%). In T-pts, 10 had tumors with multiple MUTs: (EGFR 9, and ALK 1). NT-pts did not receive targeted therapy because of unknown mutation status (55%), absence of any MUT (29%), lack of “druggable” MUT (6%) or resected or asymptomatic stable disease in patients with tumors harboring targetable MUTs (10%). Median overall survival (mOS) in T-pts was 47 months (mo) compared with 23 mo in NT-pts (HR 0.56, 95% CI: 0.44-0.71, P<0.001). Patients with EGFR- or ALK-mutant tumors who did not require systemic treatment because of clinically and radiologically stable disease had the longest survival (median >47 mo). Caucasian vs. Asian ethnicity (p=0.014) and ECOG PS 0 vs. 1 (p=0.004) in T-pts and ECOG PS 0-1 vs 2-3 (p<0.001) in NT-pts were associated with longer survival. EGFR Exon 21 MUT was associated with a trend towards shorter survival than Exon 19 (HR 1.48, 95% CI: 0.95-2.3, P=0.083). Patients with EGFR MUTs and brain metastases at diagnosis had similar survival to those without (HR 1.16, 95% CI: 0.74-1.8, P=0.514). However, in the 74 patients with CNS metastases at diagnosis EGFR Exon 21 compared to Exon 19 was associated with significantly shorter survival (med 21 vs 57 mo; HR 3.96, 95% CI: 1.73-9.05, P<0.001). Conclusions: Never smokers with advanced NSCLC can achieve long survival when treated with targeted therapy. Our observation of poorer survival in patients with EGFR Exon 21 and brain metastases warrants further study.
    ASCO Annual Meeting 2015; 05/2015
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    ABSTRACT: Understanding the significance of bacterial species that colonize and persist in cystic fibrosis (CF) airways requires a detailed examination of bacterial community structure across a broad range of age and disease stage. We used 16S ribosomal RNA sequencing to characterize the lung microbiota in 269 CF patients spanning a 60 year age range, including 76 pediatric samples from patients of age 4-17, and a broad cross-section of disease status to identify features of bacterial community structure and their relationship to disease stage and age. The CF lung microbiota shows significant inter-individual variability in community structure, composition and diversity. The core microbiota consists of five genera - Streptococcus, Prevotella, Rothia, Veillonella and Actinomyces. CF-associated pathogens such as Pseudomonas, Burkholderia, Stenotrophomonas and Achromobacter are less prevalent than core genera, but have a strong tendency to dominate the bacterial community when present. Community diversity and lung function are greatest in patients less than 10 years of age and lower in older age groups, plateauing at approximately age 25. Lower community diversity correlates with worse lung function in a multivariate regression model. Infection by Pseudomonas correlates with age-associated trends in community diversity and lung function.
    Scientific Reports 05/2015; 5:10241. DOI:10.1038/srep10241 · 5.58 Impact Factor
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    ABSTRACT: Testing for EGFR mutations and ALK rearrangement has become standard in managing advanced non-small cell lung cancer (NSCLC). However, many institutions in Europe, North America, and other world regions continue to face a common challenge of facilitating timely molecular testing with rapid result turnaround time. We assessed the prevalence of biomarker testing for advanced NSCLC patients and whether testing affected the timeliness of treatment decisions. We conducted a retrospective chart review of a random sample of one quarter of all patients with advanced NSCLC referred to the Princess Margaret Cancer Centre from April 1, 2010 to March 31, 2013. Of 300 patients reviewed, 175 seen by medical oncology had non-squamous NSCLC, 72% of whom had biomarker testing performed. Patients tested for biomarkers were more likely to be female (47% vs. 21%, p=0.002), Asian (27% vs. 6%, p=0.005) and never-smokers (42% vs. 8%, p<0.0001). Only 21% of patients with biomarker testing had results available at their initial oncology consultation. This group had a shorter median time from consultation to treatment decision (0 vs. 22 days, p=0.0008) and time to treatment start (16 vs. 29, p=0.004). Thirteen percent underwent repeat biopsy for molecular testing after the initial consultation. Of those with positive EGFR or ALK results, 19% started chemotherapy before biomarker results became available. Awaiting biomarker testing results can delay treatment decisions and treatment initiation for patients with advanced NSCLC. This may be avoided by incorporating reflex biomarker testing into diagnostic algorithms for NSCLC at the level of the pathologist, and further education of specialists involved in obtaining diagnostic cancer specimens to ensure they are sufficient for molecular testing. © The Author 2015. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.
    Annals of Oncology 04/2015; 26(7). DOI:10.1093/annonc/mdv208 · 7.04 Impact Factor
  • The Journal of Heart and Lung Transplantation 04/2015; 34(4):S93. DOI:10.1016/j.healun.2015.01.247 · 6.65 Impact Factor
  • The Journal of Heart and Lung Transplantation 04/2015; 34(4):S91-S92. DOI:10.1016/j.healun.2015.01.244 · 6.65 Impact Factor
  • T. Martinu · H. Oishi · D.M. Hwang · M. Cypel · M. Liu · S. Keshavjee
    The Journal of Heart and Lung Transplantation 04/2015; 34(4):S106-S107. DOI:10.1016/j.healun.2015.01.284 · 6.65 Impact Factor
  • The Journal of Heart and Lung Transplantation 04/2015; 34(4):S52-S53. DOI:10.1016/j.healun.2015.01.131 · 6.65 Impact Factor
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    ABSTRACT: The contribution of bone marrow cells (BMC) in lung repair is controversial. We previously reported a subpopulation of BMC that express Clara cell secretory protein (CCSP). To determine the contribution of endogenous CCSP(+) BMC to airway regeneration we performed bone marrow transplantation studies using the CCtk mouse, which expresses a thymidine kinase suicide gene under regulation of the CCSP promoter. Mice were transplanted with wild type or CCtk BMC and treated with ganciclovir to eliminate CCSP(+) cells. After airway injury using naphthalene, mice depleted of CCSP(+) BMC had more inflammatory cells in lung and decreased levels of oxygen in arterial blood. They also had reduced expression of airway epithelial genes and less Clara cells compared to control mice that had intact CCSP(+) BMC and bone marrow derived CCSP(+) cells in the airways. After naphthalene injury, administration of CCSP reproduced the beneficial effect of CCSP(+) BMC by improving recovery of airway epithelium, reducing lung inflammation and increasing oxygen in arterial blood from mice depleted of CCSP(+) BMC. Our data demonstrates that ablation of CCSP(+) BMC delays airway recovery and suggests the beneficial effect of CCSP(+) BMC in lung recovery is in part due to production of CCSP itself.Molecular Therapy (2014); doi:10.1038/mt.2014.223.
    Molecular Therapy 11/2014; 23(3). DOI:10.1038/mt.2014.223 · 6.23 Impact Factor
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    ABSTRACT: Introduction: Fluorescence in situ hybridization (FISH) is currently the standard for diagnosing anaplastic lymphoma kinase (ALK)-rearranged (ALK+) lung cancers for ALK inhibitor therapies. ALK immunohistochemistry (IHC) may serve as a screening and alternative diagnostic method. The Canadian ALK (CALK) study was initiated to implement a multicenter optimization and standardization of laboratory developed ALK IHC and FISH tests across 14 hospitals. Methods: Twenty-eight lung adenocarcinomas with known ALK status were used as blinded study samples. Thirteen laboratories performed IHC using locally developed staining protocols for 5A4, ALK1, or D5F3 antibodies; results were assessed by H-score. Twelve centers conducted FISH using protocols based on Vysis' ALK break-apart FISH kit. Initial IHC results were used to optimize local IHC protocols, followed by a repeat IHC study to assess the results of standardization. Three laboratories conducted a prospective parallel IHC and FISH analysis on 411 consecutive clinical samples using post-validation optimized assays. Results: Among study samples, FISH demonstrated 22 consensus ALK+ and six ALK wild type tumors. Preoptimization IHC scores from 12 centers with 5A4 and the percent abnormal cells by FISH from 12 centers showed intraclass correlation coefficients of 0.83 and 0.68, respectively. IHC optimization improved the intraclass correlation coefficients to 0.94. Factors affecting FISH scoring and outliers were identified. Post-optimization concurrent IHC/FISH testing in 373 informative cases revealed 100% sensitivity and specificity for IHC versus FISH. Conclusions: Multicenter standardization study may accelerate the implementation of ALK testing protocols across a country/region. Our data support the use of an appropriately validated IHC assay to screen for ALK+ lung cancers.
    Journal of Thoracic Oncology 09/2014; 9(9):1255-1263. DOI:10.1097/JTO.0000000000000239 · 5.28 Impact Factor
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    ABSTRACT: Background: It is estimated that millions of North Americans would qualify for lung cancer screening and that billions of dollars of national health expenditures would be required to support population-based computed tomography lung cancer screening programs. The decision to implement such programs should be informed by data on resource utilization and costs. Methods: Resource utilization data were collected prospectively from 2059 participants in the Pan-Canadian Early Detection of Lung Cancer Study using low-dose computed tomography (LDCT). Participants who had 2% or greater lung cancer risk over 3 years using a risk prediction tool were recruited from seven major cities across Canada. A cost analysis was conducted from the Canadian public payer's perspective for resources that were used for the screening and treatment of lung cancer in the initial years of the study. Results: The average per-person cost for screening individuals with LDCT was $453 (95% confidence interval [CI], $400-$505) for the initial 18-months of screening following a baseline scan. The screening costs were highly dependent on the detected lung nodule size, presence of cancer, screening intervention, and the screening center. The mean per-person cost of treating lung cancer with curative surgery was $33,344 (95% CI, $31,553-$34,935) over 2 years. This was lower than the cost of treating advanced-stage lung cancer with chemotherapy, radiotherapy, or supportive care alone, ($47,792; 95% CI, $43,254-$52,200; p = 0.061). Conclusion: In the Pan-Canadian study, the average cost to screen individuals with a high risk for developing lung cancer using LDCT and the average initial cost of curative intent treatment were lower than the average per-person cost of treating advanced stage lung cancer which infrequently results in a cure.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 08/2014; 9(10). DOI:10.1097/JTO.0000000000000283 · 5.28 Impact Factor
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    ABSTRACT: Introduction: To determine long-term outcome and risk factors for recurrence after thymectomy. Methods: Patients who underwent thymectomy (n = 262) for a thymic tumor (1986-2010) were identified from a prospective database. Patients were classified according to World Helath Organization (WHO) histologic classification, Masaoka staging system, and completeness of resection. Risk factors for recurrence: WHO histology, tumor size, Masaoka stage and completeness of resection were analyzed. Results: Of 262 patients, 51% were female, median age was 55 years, and 39% had myasthenia gravis. Median follow-up was 7.5 years, median tumor size was 5.4 cm, and Masaoka stage distribution was: I (25%), II (47%), III (17%), IV (4%), and (7%) not classified. Of 200 patients classified under the WHO system, there were (7%) type A, (22%) type AB, and (71%) type B; 83% had complete resection. One-hundred and sixty-nine patients received adjuvant radiotherapy, eight adjuvant chemoradiotherapy and 14 neoadjuvant chemoradiotherapy. Overall survival was 95% at 5 years, 91% at 10 years and 91% at 15 years. Recurrence occurred in 12 patients and disease-related death in four patients. Five patients underwent re-resection for recurrence with survival of 2-15 years. Only Masaoka stage and tumor size were associated with statistically significant risk of recurrence on multivariate analysis. Conclusion: Resectable thymoma is associated with excellent prognosis. Aggressive resection of recurrent disease yielded excellent long-term results. Higher Masaoka stage is associated with a greater chance of incomplete resection. Higher Masaoka stage and increasing tumor size are independent factors associated with recurrence.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 07/2014; 9(7):1018-22. DOI:10.1097/JTO.0000000000000215 · 5.28 Impact Factor
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    ABSTRACT: QUESTION What types of specimens suspected to be or diagnosed as lung cancer should or should not have routine secondary pathology review? Available from Cancer Care Ontario at: https://www.cancercare.on.ca/common/pages/UserFile.aspx?fileId=311334
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    ABSTRACT: Introduction: Epidermal growth factor receptor (EGFR) mutation testing has become critical in the treatment of patients with advanced non-small-cell lung cancer. This study involves a large cohort and epidemiologically unselected series of EGFR mutation testing for patients with nonsquamous non-small-cell lung cancer in a North American population to determine sample-related factors that influence success in clinical EGFR testing. Methods: Data from consecutive cases of Canadian province-wide testing at a centralized diagnostic laboratory for a 24-month period were reviewed. Samples were tested for exon-19 deletion and exon-21 L858R mutations using a validated polymerase chain reaction method with 1% to 5% detection sensitivity. Results: From 2651 samples submitted, 2404 samples were tested with 2293 samples eligible for analysis (1780 histology and 513 cytology specimens). The overall test-failure rate was 5.4% with overall mutation rate of 20.6%. No significant differences in the failure rate, mutation rate, or mutation type were found between histology and cytology samples. Although tumor cellularity was significantly associated with test-success or mutation rates in histology and cytology specimens, respectively, mutations could be detected in all specimen types. Significant rates of EGFR mutation were detected in cases with thyroid transcription factor (TTF)-1-negative immunohistochemistry (6.7%) and mucinous component (9.0%). Conclusions: EGFR mutation testing should be attempted in any specimen, whether histologic or cytologic. Samples should not be excluded from testing based on TTF-1 status or histologic features. Pathologists should report the amount of available tumor for testing. However, suboptimal samples with a negative EGFR mutation result should be considered for repeat testing with an alternate sample.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 06/2014; 9(7). DOI:10.1097/JTO.0000000000000196 · 5.28 Impact Factor
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    ABSTRACT: Background: Isolated lung perfusion (ILP) can enhance the treatment of lung metastases, allowing the localized delivery of drugs to the lungs, without systemic exposure. Previously, short-term ILP (± 30 minutes) resulted in variable efficacy and frequent toxicity. We developed a technique that minimizes perfusion-related injury to the lung and allows an extended perfusion time. Using our strategy, our objective is to demonstrate the feasibility and safety of ILP with doxorubicin (Dox). Methods: In pigs, left pulmonary artery and veins (PVs) were cannulated and clamped. Left lung ILP with a protective mode of ventilation/perfusion was performed for 4h. Dox 75 mg/m2 alone or with ifosfamide (Ifos) 6 g/m2 is a standard regimen currently used systemically for patients with metastatic sarcomas. Based on this, Dox 75mg/m2 (group 1, n=4), 150 mg/m2 (group 2, n=2), 225 mg/m2 (group 3, n=2), and Dox 75mg/m2 + Ifos 6 g/m2(group 4, n=3) were administered at the start of ILP. After 4h ILP, cannulas were removed and blood reperfusion was allowed for more 4h. Lung physiology (Lphys) was assessed with peak airway pressure (Pawp), dynamic compliance (Cdyn), pulmonary vascular resistance (PVR), and PVs oxygenation (P/F ratio). Lung biopsies were obtained before, after ILP and after reperfusion for histological assessment of acute lung injury (ALI). Lung tissue levels of Dox were measured at the end of reperfusion and systemic levels of Dox were analyzed hourly. Results: In groups 1 and 4, Lphys was stable during 4h ILP period and reperfusion, without histologic ALI (p=0.12 and p=0.36). In group 2, P/F ratio dropped at reperfusion, and in group 3, severe ALI happened during ILP (increase of Pawp and PVR, and drop in Cdyn). In groups 1 and 4, mean tissue levels of Dox were 70.3 ug/g, homogeneously distributed in the lung (p=0.12). No Dox was detected systemically during the experiment. Conclusions: ILP with standard doses of chemotherapy (groups 1 and 4) was well tolerated using our ILP strategy for an extended period of time and without measurable ALI. In these groups, comparing to previous large animal studies, we found 2-3 x higher tissue levels of Dox, demonstrating the protective effect of our ILP strategy.
    2014 ASCO Annual Meeting, Chicago; 05/2014
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    ABSTRACT: The increasing use of nanomaterials raises concerns about the long-term effects of chronic nanoparticle exposure on human health. However, nanoparticle exposure is difficult to evaluate non-invasively using current measurement techniques. Here we show that the skin is an important site of nanoparticle accumulation following systemic administration. Mice injected with high doses of gold nanoparticles have visibly blue skin while quantum dottreated animals fluoresce under ultraviolet excitation. More importantly, elemental analysis of excised skin correlates with the injected dose and nanoparticle accumulation in the liver and spleen. We propose that skin analysis may be a simple strategy to quantify systemic nanoparticle exposure and predict nanoparticle fate in vivo. Our results suggest that in the future, dermal accumulation may also be exploited to trigger the release of ultraviolet and visible light-sensitive therapeutics that are currently impractical in vivo due to limits in optical penetration of tissues at these wavelengths.
    Nature Communications 05/2014; 5(3796). DOI:10.1038/ncomms4796 · 11.47 Impact Factor
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    ABSTRACT: Supplementary information available for this article at http://www.nature.com/ncomms/2014/140513/ncomms4796/suppinfo/ncomms4796_S1.html

Publication Stats

772 Citations
441.59 Total Impact Points


  • 2008–2015
    • University of Toronto
      • • Department of Surgery
      • • Department of Laboratory Medicine and Pathobiology
      • • Department of Medical Imaging
      Toronto, Ontario, Canada
    • Saint Michael's Medical Center
      Newark, New Jersey, United States
  • 2014
    • Sir Charles Gairdner Hospital
      Perth City, Western Australia, Australia
  • 2007–2013
    • University Health Network
      • Department of Pathology
      Toronto, Ontario, Canada
  • 2012
    • UHN: Toronto General Hospital
      Toronto, Ontario, Canada
  • 2009
    • Ontario Institute for Cancer Research
      Toronto, Ontario, Canada