Browsing by Author "Lama, Vibha N."

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Overexpression of Decay Accelerating Factor Mitigates Fibrotic Responses to Lung Injury
    (American Thoracic Society, 2022) Vittal, Ragini; Fisher, Amanda J.; Thompson, Eric L.; Cipolla, Ellyse M.; Gu, Hongmei; Mickler, Elizabeth A.; Varre, Ananya; Agarwal, Manisha; Kim, Kevin K.; Vasko, Michael R.; Moore, Bethany B.; Lama, Vibha N.; Medicine, School of Medicine
    CD55 or decay accelerating factor (DAF), a ubiquitously expressed glycosylphosphatidylinositol (GPI)-anchored protein, confers a protective threshold against complement dysregulation which is linked to the pathogenesis of idiopathic pulmonary fibrosis (IPF). Since lung fibrosis is associated with downregulation of DAF, we hypothesize that overexpression of DAF in fibrosed lungs will limit fibrotic injury by restraining complement dysregulation. Normal primary human alveolar type II epithelial cells (AECs) exposed to exogenous complement 3a or 5a, and primary AECs purified from IPF lungs demonstrated decreased membrane-bound DAF expression with concurrent increase in the endoplasmic reticulum (ER) stress protein, ATF6. Increased loss of extracellular cleaved DAF fragments was detected in normal human AECs exposed to complement 3a or 5a, and in lungs of IPF patients. C3a-induced ATF6 expression and DAF loss was inhibited using pertussis toxin (an enzymatic inactivator of G-protein coupled receptors), in murine AECs. Treatment with soluble DAF abrogated tunicamycin-induced C3a secretion and ER stress (ATF6 and BiP expression) and restored epithelial cadherin. Bleomycin-injured fibrotic mice subjected to lentiviral overexpression of DAF demonstrated diminished levels of local collagen deposition and complement activation. Further analyses showed diminished release of DAF fragments, as well as reduction in apoptosis (TUNEL and caspase 3/7 activity), and ER stress-related transcripts. Loss-of-function studies using Daf1 siRNA demonstrated worsened lung fibrosis detected by higher mRNA levels of Col1a1 and epithelial injury-related Muc1 and Snai1, with exacerbated local deposition of C5b-9. Our studies provide a rationale for rescuing fibrotic lungs via DAF induction that will restrain complement dysregulation and lung injury.
  • Thumbnail Image
    Item
    Preoperative plasma club (clara) cell secretory protein levels are associated with primary graft dysfunction after lung transplantation
    (Wiley Blackwell (Blackwell Publishing), 2014-02) Shah, Rupal J.; Wickersham, Nancy; Lederer, David J.; Palmer, Scott M.; Cantu, Edward; Diamond, Joshua M.; Kawut, Steven M.; Lama, Vibha N.; Bhorade, Sangeeta; Crespo, Maria; Demissie, Ejigayehu; Sonett, Joshua; Wille, Keith; Orens, Jonathan; Weinacker, Ann; Shah, Pali; Arcasoy, Selim; Wilkes, David S.; Christie, Jason D.; Ware, Lorraine B.; Department of Medicine, IU School of Medicine
    Inherent recipient factors, including pretransplant diagnosis, obesity and elevated pulmonary pressures, are established primary graft dysfunction (PGD) risks. We evaluated the relationship between preoperative lung injury biomarkers and PGD to gain further mechanistic insight in recipients. We performed a prospective cohort study of recipients in the Lung Transplant Outcomes Group enrolled between 2002 and 2010. Our primary outcome was Grade 3 PGD on Day 2 or 3. We measured preoperative plasma levels of five biomarkers (CC-16, sRAGE, ICAM-1, IL-8 and Protein C) that were previously associated with PGD when measured at the postoperative time point. We used multivariable logistic regression to adjust for potential confounders. Of 714 subjects, 130 (18%) developed PGD. Median CC-16 levels were elevated in subjects with PGD (10.1 vs. 6.0, p<0.001). CC-16 was associated with PGD in nonidiopathic pulmonary fibrosis (non-IPF) subjects (OR for highest quartile of CC-16: 2.87, 95% CI: 1.37, 6.00, p=0.005) but not in subjects with IPF (OR 1.38, 95% CI: 0.43, 4.45, p=0.59). After adjustment, preoperative CC-16 levels remained associated with PGD (OR: 3.03, 95% CI: 1.26, 7.30, p=0.013) in non-IPF subjects. Our study suggests the importance of preexisting airway epithelial injury in PGD. Markers of airway epithelial injury may be helpful in pretransplant risk stratification in specific recipients.
  • Thumbnail Image
    Item
    Quantitative Evidence for Revising the Definition of Primary Graft Dysfunction after Lung Transplant
    (American Thoracic Society, 2018-01-15) Cantu, Edward; Diamond, Joshua M.; Suzuki, Yoshikazu; Lasky, Jared; Schaufler, Christian; Lim, Brian; Shah, Rupal; Porteous, Mary; Lederer, David J.; Kawut, Steven M.; Palmer, Scott M.; Snyder, Laurie D.; Hartwig, Matthew G.; Lama, Vibha N.; Bhorade, Sangeeta; Bermudez, Christian; Crespo, Maria; McDyer, John; Wille, Keith; Orens, Jonathan; Shah, Pali D.; Weinacker, Ann; Weill, David; Wilkes, David; Roe, David; Hage, Chadi; Ware, Lorraine B.; Bellamy, Scarlett L.; Christie, Jason D.; Medicine, School of Medicine
    RATIONALE: Primary graft dysfunction (PGD) is a form of acute lung injury that occurs after lung transplantation. The definition of PGD was standardized in 2005. Since that time, clinical practice has evolved, and this definition is increasingly used as a primary endpoint for clinical trials; therefore, validation is warranted. OBJECTIVES: We sought to determine whether refinements to the 2005 consensus definition could further improve construct validity. METHODS: Data from the Lung Transplant Outcomes Group multicenter cohort were used to compare variations on the PGD definition, including alternate oxygenation thresholds, inclusion of additional severity groups, and effects of procedure type and mechanical ventilation. Convergent and divergent validity were compared for mortality prediction and concurrent lung injury biomarker discrimination. MEASUREMENTS AND MAIN RESULTS: A total of 1,179 subjects from 10 centers were enrolled from 2007 to 2012. Median length of follow-up was 4 years (interquartile range = 2.4-5.9). No mortality differences were noted between no PGD (grade 0) and mild PGD (grade 1). Significantly better mortality discrimination was evident for all definitions using later time points (48, 72, or 48-72 hours; P < 0.001). Biomarker divergent discrimination was superior when collapsing grades 0 and 1. Additional severity grades, use of mechanical ventilation, and transplant procedure type had minimal or no effect on mortality or biomarker discrimination. CONCLUSIONS: The PGD consensus definition can be simplified by combining lower PGD grades. Construct validity of grading was present regardless of transplant procedure type or use of mechanical ventilation. Additional severity categories had minimal impact on mortality or biomarker discrimination.
  • Thumbnail Image
    Item
    The relationship between plasma lipid peroxidation products and primary graft dysfunction after lung transplantation is modified by donor smoking and reperfusion hyperoxia
    (Elsevier, 2016-04) Diamond, Joshua M.; Porteous, Mary K.; Roberts, L. Jackson; Wickersham, Nancy; Rushefski, Melanie; Kawut, Steven M.; Shah, Rupal J.; Cantu, Edward; Lederer, David J.; Chatterjee, Shampa; Lama, Vibha N.; Bhorade, Sangeeta; Crespo, Maria; McDyer, John; Wille, Keith; Orens, Jonathan; Weinacker, Ann; Arcasoy, Selim; Shah, Pali D.; Wilkes, David S.; Hage, Chadi; Palmer, Scott M.; Snyder, Laurie; Calfee, Carolyn S.; Ware, Lorraine B.; Christie, Jason D.; Medicine, School of Medicine
    BACKGROUND: Donor smoking history and higher fraction of inspired oxygen (FIO2) at reperfusion are associated with primary graft dysfunction (PGD) after lung transplantation. We hypothesized that oxidative injury biomarkers would be elevated in PGD, with higher levels associated with donor exposure to cigarette smoke and recipient hyperoxia at reperfusion. METHODS: We performed a nested case-control study of 72 lung transplant recipients from the Lung Transplant Outcomes Group cohort. Using mass spectroscopy, F2-isoprostanes and isofurans were measured in plasma collected after transplantation. Cases were defined in 2 ways: grade 3 PGD present at day 2 or day 3 after reperfusion (severe PGD) or any grade 3 PGD (any PGD). RESULTS: There were 31 severe PGD cases with 41 controls and 35 any PGD cases with 37 controls. Plasma F2-isoprostane levels were higher in severe PGD cases compared with controls (28.6 pg/ml vs 19.8 pg/ml, p = 0.03). Plasma F2-isoprostane levels were higher in severe PGD cases compared with controls (29.6 pg/ml vs 19.0 pg/ml, p = 0.03) among patients reperfused with FIO2 >40%. Among recipients of lungs from donors with smoke exposure, plasma F2-isoprostane (38.2 pg/ml vs 22.5 pg/ml, p = 0.046) and isofuran (66.9 pg/ml vs 34.6 pg/ml, p = 0.046) levels were higher in severe PGD compared with control subjects. CONCLUSIONS: Plasma levels of lipid peroxidation products are higher in patients with severe PGD, in recipients of lungs from donors with smoke exposure, and in recipients exposed to higher Fio2 at reperfusion. Oxidative injury is an important mechanism of PGD and may be magnified by donor exposure to cigarette smoke and hyperoxia at reperfusion.
  • Thumbnail Image
    Item
    Risk of Primary Graft Dysfunction Following Lung Transplantation in Selected Adults with Connective Tissue Disease-associated Interstitial Lung Disease
    (Elsevier, 2021) Natalini, Jake G.; Diamond, Joshua M.; Porteous, Mary K.; Lederer, David J.; Wille, Keith M.; Weinacker, Ann B.; Orens, Jonathan B.; Shah, Pali D.; Lama, Vibha N.; McDyer, John F.; Snyder, Laurie D.; Hage, Chadi A.; Singer, Jonathan P.; Ware, Lorraine B.; Cantu, Edward; Oyster, Michelle; Kalman, Laurel; Christie, Jason D.; Kawut, Steven M.; Bernstein, Elana J.; Medicine, School of Medicine
    Background: Previous studies have reported similarities in long-term outcomes following lung transplantation for connective tissue disease-associated interstitial lung disease (CTD-ILD) and idiopathic pulmonary fibrosis (IPF). However, it is unknown whether CTD-ILD patients are at increased risk of primary graft dysfunction (PGD), delays in extubation, or longer index hospitalizations following transplant compared to IPF patients. Methods: We performed a multicenter retrospective cohort study of CTD-ILD and IPF patients enrolled in the Lung Transplant Outcomes Group registry who underwent lung transplantation between 2012 and 2018. We utilized mixed effects logistic regression and stratified Cox proportional hazards regression to determine whether CTD-ILD was independently associated with increased risk for grade 3 PGD or delays in post-transplant extubation and hospital discharge compared to IPF. Results: A total of 32.7% (33/101) of patients with CTD-ILD and 28.9% (145/501) of patients with IPF developed grade 3 PGD 48-72 hours after transplant. There were no significant differences in odds of grade 3 PGD among patients with CTD-ILD compared to those with IPF (adjusted OR 1.12, 95% CI 0.64-1.97, p = 0.69), nor was CTD-ILD independently associated with a longer post-transplant time to extubation (adjusted HR for first extubation 0.87, 95% CI 0.66-1.13, p = 0.30). However, CTD-ILD was independently associated with a longer post-transplant hospital length of stay (median 23 days [IQR 14-35 days] vs17 days [IQR 12-28 days], adjusted HR for hospital discharge 0.68, 95% CI 0.51-0.90, p = 0.008). Conclusion: Patients with CTD-ILD experienced significantly longer postoperative hospitalizations compared to IPF patients without an increased risk of grade 3 PGD.