Bio

Clinical Focus


  • Ischemia-Reperfusion Injury
  • Heart-Lung Transplantation
  • Pediatric Pulmonary
  • Lung Transplantation
  • Pulmonary Medicine/Cystic Fibrosis, Pediatric
  • Lung Inflammation

Academic Appointments


Administrative Appointments


  • Director, Pediatric Pulmonary Function Lab (2004 - Present)
  • Director, Pediatric Lung and Heart-Lung Transplant Program (2004 - Present)

Professional Education


  • Board Certification: Pediatric Pulmonary, American Board of Pediatrics (1996)
  • Residency:Children's Hospital of Los Angeles (1992) CA
  • Fellowship:Johns Hopkins University (1995) MD
  • Internship:Children's Hospital of Los Angeles (1990) CA
  • Medical Education:UCLA Medical Center (1989) CA
  • Fellow, The Johns Hopkins University, Pediatric Pulmonary Medicine (1995)
  • BA, Univ. of California, Berkeley, Anatomy and Physiology (1983)
  • MD, Drew-UCLA School of Medicine, Medicine (1989)

Community and International Work


  • Chair, Pediatric Committee of the California Thoracic Society

    Topic

    Development of guidelines for care for pediatric respiratory disease

    Partnering Organization(s)

    American Lung Association

    Populations Served

    Children who have chronic lung disease in the state of California

    Location

    California

    Ongoing Project

    Yes

    Opportunities for Student Involvement

    No

Research & Scholarship

Current Research and Scholarly Interests


I have participated in multiple clinical studies and have contributed to the development of therapeutic interventions designed specifically for the treatment of lung disease in children and adults with CF. Initially, my research interests concentrated on gene therapy for CF. Over time, the emphasis of my research led to investigator-initiated clinical research studies which have produced the description of novel mechanisms that drive the inflammatory milieu of the CF airway. With support from the CF Research Center resources at Stanford University, the CF Foundation, and the Food and Drug Administration, I have successfully completed Phase I and Phase IIa clinical research studies to assess the efficacy of N-acetylcysteine (NAC) in a novel approach to reduce inflammation in the lungs of CF patients. Building upon the foundation of these initial trials, and with CFF support, I am continuing studies as the Principal Investigator for a 3-year, Phase IIb, multi-center trial for NAC in CF that began in November of 2008.
As the pulmonary division has grown over the years, my clinical and academic interests have broadened to include pediatric lung transplantation. In 2002, I subsumed the role of program director for the pediatric pulmonary lung and heart-lung transplant program at LPCH. As a result, we are the 5th largest pediatric lung and heart-lung transplant program in the United States (the 2nd largest pediatric heart-lung transplant program). At least 60 infants and children have been evaluated at the center for pediatric lung and heart-lung transplantation at LPCH and 19 children have received transplants in this period of time. My career plans are to foster further growth of the center with the goal to create a translational pediatric research center for lung and heart-lung transplantation at LPCH.
This nascent field of medicine is one in which little is known of the cellular and molecular mechanisms within transplantation dynamics and where the possibilities for discovery and therapeutic advances are considerable. In this field, I have co-authored several peer-reviewed manuscripts and abstracts, and I am a PI in international studies regarding outcomes for children who have undergone lung and heart-lung transplantation. The pediatric lung and heart-lung transplant program at LPCH is one of seven sites participating in an international prospective study funded by the Clinical Trials in Organ Transplantation in Children (CTOT-C) from the NIH that will examine the effect that viral infections may have on the mechanisms of lung allograft rejection (development of bronchiolitis obliterans, OB) in children. OB is the single most important life-limiting process affecting lung and heart-lung transplant recipients. It is a fibrosing process that obliterates the allograft airway lumen. Once the process is initiated, it is difficult to abrogate. The etiology is poorly understood, and multifactorial. Most transplant researchers agree that ischemia-reperfusion injury (IRI) creates an abnormal cellular redox milieu that contributes to neutrophilic inflammation. Histopathologically, neutrophilic inflammation heralds the pathophysiologic consequences that result in graft failure due to OB. To date, the association of these early IRI and redox events to the occurrence of OB has not been fully investigated.

Clinical Trials


  • Infant Study of Inhaled Saline in Cystic Fibrosis Recruiting

    The purpose of this study is to assess whether 7% hypertonic saline (HS) is an effective and safe therapy in infants and young children with CF.

    View full details

  • Rare Genetic Disorders of the Breathing Airways Recruiting

    Mucociliary clearance, in which mucus secretions are cleared from the breathing airways, is the primary defense mechanism for the lungs. Inhaled particles, including microbes that can cause infections, are normally entrapped in mucus on the airway surfaces and then cleared out by the coordinated action of tiny hair-like structures called cilia. Individuals with primary ciliary dyskinesia, variant cystic fibrosis, and pseudohypoaldosteronism have defective mucociliary clearance. The purpose of this study is to collect clinical and genetic information about these three airway diseases to improve current diagnostic procedures.

    View full details

  • The EPIC Observational Study Not Recruiting

    The purpose of this study is to better define risk factors preceding first isolation of Pseudomonas aeruginosa (Pa) from respiratory cultures in cystic fibrosis (CF) lung disease and to better define clinical outcomes associated with acquisition of Pa. This study will also collect and bank DNA samples for current and future studies designed to enhance the understanding of the pathogenesis of CF.

    Stanford is currently not accepting patients for this trial. For more information, please contact Colleen Dunn, (650) 736 - 0388.

    View full details

Teaching

2013-14 Courses


Publications

Journal Articles


  • Activation of critical, host-induced, metabolic and stress pathways marks neutrophil entry into cystic fibrosis lungs PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Makam, M., Diaz, D., Laval, J., Gernez, Y., Conrad, C. K., Dunn, C. E., Davies, Z. A., Moss, R. B., Herzenberg, L. A., Herzenberg, L. A., Tirouvanziam, R. 2009; 106 (14): 5779-5783

    Abstract

    Cystic fibrosis (CF) patients undergo progressive airway destruction caused in part by chronic neutrophilic inflammation. While opportunistic pathogens infecting CF airways can cause inflammation, we hypothesized that host-derived metabolic and stress signals would also play a role in this process. We show that neutrophils that have entered CF airways have increased phosphorylation of the eukaryotic initiation factor 4E and its partner the 4E-binding protein 1; 2 key effectors in the growth factor- and amino acid-regulated mammalian target of rapamycin (mTOR) pathway. Furthermore CF airway neutrophils display increased phosphorylation of the cAMP response element binding protein (CREB), a major transcriptional coactivator in stress signaling cascades. These active intracellular pathways are associated with increased surface expression of critical adaptor molecules, including the growth factor receptor CD114 and the receptor for advanced glycation end-products (RAGE), a CREB inducer and sensor for host-derived damage-associated molecular patterns (DAMPs). Most CF airway fluids lack any detectable soluble RAGE, an inhibitory decoy receptor for DAMPs. Concomitantly, CF airway fluids displayed high and consequently unopposed levels of S100A12; a potent mucosa- and neutrophil-derived DAMP. CF airway neutrophils also show increased surface levels of 2 critical CREB targets, the purine-recycling enzyme CD39 and the multifunctional, mTOR-inducing CXCR4 receptor. This coordinated set of events occurs in all patients, even in the context of minimal airway inflammation and well-preserved lung function. Taken together, our data demonstrate an early and sustained activation of host-responsive metabolic and stress pathways upon neutrophil entry into CF airways, suggesting potential targets for therapeutic modulation.

    View details for DOI 10.1073/pnas.0813410106

    View details for Web of Science ID 000264967500059

    View details for PubMedID 19293384

  • Activation of critical, host-induced, metabolic and stress pathways marks neutrophil entry into cystic fibrosis lungs Proc Natl Acad Sci Makam Megha, Diaz D, Laval J, Gernez Y, Conrad CK 2009; 106 (14): 5779
  • Increased mortality after pulmonary fungal infection within the first year after pediatric lung transplantation JOURNAL OF HEART AND LUNG TRANSPLANTATION Danziger-Isakov, L. A., Worley, S., Arrigain, S., Aurora, P., Ballmann, M., Boyer, D., Conrad, C., Eichler, I., Elidemir, O., Goldfarb, S., Mallory, G. B., Michaels, M. G., Michelson, P., Mogayzel, P. J., Parakininkas, D., Solomon, M., Visner, G., Sweet, S., Faro, A. 2008; 27 (6): 655-661

    Abstract

    Risk factors, morbidity and mortality from pulmonary fungal infections (PFIs) within the first year after pediatric lung transplant have not previously been characterized.A retrospective, multicenter study from 1988 to 2005 was conducted with institutional approval from the 12 participating centers in North America and Europe. Data were recorded for the first post-transplant year. The log-rank test assessed for the association between PFI and survival. Associations between time to PFI and risk factors were assessed by Cox proportional hazards models.Of the 555 subjects transplanted, 58 (10.5%) had 62 proven (Candida, Aspergillus or other) or probable (Aspergillus or other) PFIs within the first year post-transplant. The mean age for PFI subjects was 14.0 years vs 11.4 years for non-PFI subjects (p < 0.01). Candida and Aspergillus species were recovered equally for proven disease. Comparing subjects with PFI (n = 58) vs those without (n = 404), pre-transplant colonization was associated with PFI (hazard ratio [HR] 2.0; 95% CI 0.95 to 4.3, p = 0.067). Cytomegalovirus (CMV) mismatch, tacrolimus-based regimen and age >15 years were associated with PFI (p < 0.05). PFI was associated with any prior rejection higher than Grade A2 (HR 2.1; 95% CI 1.2 to 3.6). Cystic fibrosis, induction therapy, transplant era and type of transplant were not associated with PFI. PFI was independently associated with decreased 12-month survival (HR 3.9, 95% CI 2.2 to 6.8).Risk factors for PFI include Grade A2 rejection, repeated acute rejection, CMV-positive donor, tacrolimus-based regimen and pre-transplant colonization.

    View details for DOI 10.1016/j.healun.2008-03-010

    View details for Web of Science ID 000256597500012

    View details for PubMedID 18503966

  • Profound functional and signaling changes in viable inflammatory neutrophils homing to cystic fibrosis airways PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Tirouvanziam, R., Gernez, Y., Conrad, C. K., Moss, R. B., Schrijver, I., Dunn, C. E., Davies, Z. A., Herzenberg, L. A., Herzenberg, L. A. 2008; 105 (11): 4335-4339

    Abstract

    Blood neutrophils recruited to cystic fibrosis (CF) airways are believed to be rapidly killed by resident bacteria and to passively release elastase and other toxic by-products that promote disease progression. By single-cell analysis, we demonstrate that profound functional and signaling changes readily occur within viable neutrophils recruited to CF airways, compared with their blood counterparts. Airway neutrophils have undergone conventional activation, as shown by decreased intracellular glutathione, increased lipid raft assembly, surface mobilization of CD11b+ and CD66b+ granules, and increased levels of the cytoskeleton-associated phospho-Syk kinase. Unexpectedly, they also mobilize to the surface CD63+ elastase-rich granules, usually confined intracellularly, and lose surface expression of CD16 and CD14, both key receptors in phagocytosis. Furthermore, they express CD80, major histocompatibility complex type II, and the prostaglandin D2 receptor CD294, all normally associated with other lineages, which reflects functional reprogramming. This notion is reinforced by their decreased total phosphotyrosine levels, mirroring a postactivated stage, and increased levels of the phospho-S6 ribosomal protein, a key anabolic switch. Thus, we identified a subset of neutrophils within CF airways with a viable but dysfunctional phenotype. This subset provides a possible therapeutic target and indicates a need to revisit current paradigms of CF airway disease.

    View details for DOI 10.1073/pnas.0712386105

    View details for Web of Science ID 000254263300048

    View details for PubMedID 18334635

  • Variability in immunization guidelines in children before and after lung transplantation PEDIATRIC TRANSPLANTATION Benden, C., Danziger-Isakov, L. A., Astor, T., Aurora, P., Bluemchen, K., Boyer, D., Conrad, C., Eichler, I., Elidemir, O., Goldfarb, S., Michaels, M. G., Mogayzel, P. J., Mueller, C., Parakininkas, D., Oberkfell, D., Solomon, M., Boehler, A. 2007; 11 (8): 882-887

    Abstract

    Lung transplant candidates and recipients are at high risk of infections from vaccine-preventable diseases. However, well-established guidelines neither exist for pre- and post-transplant vaccination nor do monitoring guidelines for pediatric lung transplant recipients. To ascertain the current vaccination and monitoring practices of pediatric lung transplant centers, a self-administered questionnaire was distributed to the 18 pediatric lung transplant centers within the International Pediatric Lung Transplant Collaborative in April 2006. Sixteen of 18 centers (89%) surveyed responded. Pretransplant, national vaccination guidelines are followed. Eleven centers reported following standardized vaccination guidelines post-transplant. Vaccines were more commonly provided by the primary-care physician pretransplant (69%) rather than post-transplant (38%). Post-transplant, 50% of the centers recommend live vaccines for household contacts but not for the transplant recipient. Pretransplant monitoring of response to prior vaccination was performed inconsistently except for varicella (88%). Only 44% of the transplant centers measure for response to vaccination post-transplant, mostly hepatitis B. Current vaccination practices of pediatric lung transplant centers are heterogeneous. The lung transplant community would be well served by studies designed to evaluate the efficacy of vaccinations in this population.

    View details for DOI 10.1111/j.1399-3046.2007.00759.x

    View details for Web of Science ID 000250520100008

    View details for PubMedID 17976123

  • Novel tobramycin inhalation powder in cystic fibrosis subjects: Pharmacokinetics and safety PEDIATRIC PULMONOLOGY Geller, D. E., Konstan, M. W., Smith, J., Noonberg, S. B., Conrad, C. 2007; 42 (4): 307-313

    Abstract

    Aerosolized antibiotics are associated with a high treatment burden that can result in non-adherence to chronic therapy. We evaluated the pharmacokinetics (PK) and safety of tobramycin inhalation powder (TIP), a novel dry-powder formulation designed to deliver a high payload of tobramycin topically to the lungs for management of chronic Pseudomonas aeruginosa infections. This was a multi-center, open-label, sequential-cohort, single-dose, dose-escalation study using the standard 300 mg dose of tobramycin solution for inhalation (TSI) as an active control. Subjects were randomized to TIP or TSI in a 3:1 ratio in each of five cohorts. Measurements included serum and sputum tobramycin concentrations, administration time, serum chemistries, acute change in lung function, and adverse events (AEs). Out of 90 randomized subjects, 86 had data for safety analysis; and 84 had data for PK analysis. Serum tobramycin PK profiles were similar for TIP and TSI. Four capsules of 28 mg TIP (total tobramycin dose 112 mg) produced comparable systemic exposure to 300 mg TSI, in less than one-third the administration time. The most common AEs associated with TIP were cough (20%) and dysgeusia (17%). TIP allows for faster and more efficient pulmonary delivery of tobramycin than TSI and has a safety profile that supports continued clinical investigation. The increased rate of local respiratory tract irritation noted with TIP is not unexpected with a high-payload powder formulation. The development of dry powder inhaled antibiotics may represent an important advance in the treatment of chronic lung infections.

    View details for DOI 10.1002/ppal.20594

    View details for Web of Science ID 000245575100001

    View details for PubMedID 17352404

  • Risk factors for small bowel bacterial overgrowth in cystic fibrosis JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION Fridge, J. L., Conrad, C., Gerson, L., Castillo, R. O., Cox, K. 2007; 44 (2): 212-218

    Abstract

    The purpose of this study was to determine the prevalence of small bowel bacterial overgrowth in patients with pancreatic-insufficient cystic fibrosis (CF) compared with age-matched controls and to identify potential risk factors for small bowel bacterial overgrowth.Fifty patients, 25 pancreatic-insufficient CF study patients (mean age, 17 y) and 25 gastrointestinal clinic control patients (mean age, 15 y), completed a glucose-hydrogen breath test after an overnight fast. Study patients completed a quality-of-life questionnaire modified from the Cystic Fibrosis Questionnaire. The medical history of each patient was compared with breath test results. A positive breath test was defined as a fasting hydrogen > or =15 ppm or a rise of > or =10 ppm hydrogen over baseline during the test.The prevalence of positive breath tests was higher in the CF study group (56%) than in the control group (20%) (P = 0.02). The mean fasting hydrogen levels of patients in the study and control groups were 22 and 5 ppm (P = 0.0001). The mean questionnaire scores were not significantly different between breath test-positive and -negative study patients. The use of azithromycin was associated with an increased risk of a positive breath test. Use of laxatives and inhaled ipratropium was associated with a decreased risk of a positive breath test.Patients with CF were more likely to have elevated fasting hydrogen levels compared with controls. This suggests a high prevalence of small bowel bacterial overgrowth in CF patients. Medications commonly used by CF patients may influence intestinal health.

    View details for Web of Science ID 000243851900011

    View details for PubMedID 17255834

  • American society of transplantation executive summary on pediatric lung transplantation AMERICAN JOURNAL OF TRANSPLANTATION Faro, A., Mallory, G. B., Visner, G. A., Elidemir, O., Mogayzel, P. J., Danziger-Isakov, L., Michaels, M., Sweet, S., Michelson, P., Paranjape, S., Conrad, C., Waltz, D. A. 2007; 7 (2): 285-292

    Abstract

    Lung transplantation in children poses distinctly different challenges from those seen in the adult population. This consensus statement reviews the experience in the field of pediatric lung transplantation and highlights areas that deserve further investigation.

    View details for DOI 10.1111/j.1600-6143.2006.01612.x

    View details for Web of Science ID 000243440100005

    View details for PubMedID 17109726

  • High-dose oral N-acetylcysteine, a glutathione prodrug, modulates inflammation in cystic fibrosis PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Tirouvanziam, R., Conrad, C. K., Bottiglieri, T., Herzenberg, L. A., Moss, R. B., Herzenberg, L. A. 2006; 103 (12): 4628-4633

    Abstract

    Neutrophilic airway inflammation is a hallmark of cystic fibrosis (CF). As high oxidant producers, airway neutrophils contribute largely to the systemic redox imbalance seen in CF. In turn, this chronic and profound imbalance can impact circulating neutrophils before their migration into airways. Indeed, in 18 CF patients with stable disease, blood neutrophils were readily deficient in the pivotal antioxidant glutathione (P = 0.003, compared with 9 healthy controls). In a phase 1 study, this deficiency was improved (P = 0.025) by the glutathione prodrug N-acetylcysteine, given orally in high doses (0.6 to 1.0 g three times daily, for 4 weeks). This treatment was safe and markedly decreased sputum elastase activity (P = 0.006), the strongest predictor of CF pulmonary function. Consistently, neutrophil burden in CF airways was decreased upon treatment (P = 0.003), as was the number of airway neutrophils actively releasing elastase-rich granules (P = 0.005), as measured by flow cytometry. Pulmonary function measures were not improved, as expected with short-term treatment. After excluding data from subjects without baseline airway inflammation, positive treatment effects were more pronounced and included decreased sputum IL-8 levels (P = 0.032). Thus, high-dose oral N-acetylcysteine has the potential to counter the intertwined redox and inflammatory imbalances in CF.

    View details for DOI 10.1073/pnas.0511304103

    View details for Web of Science ID 000236362600055

    View details for PubMedID 16537378

  • Mutations in the beta-subunit of the epithelial Na+ channel in patients with a cystic fibrosis-like syndrome HUMAN MOLECULAR GENETICS Sheridan, M. B., Fong, P. Y., Groman, J. D., Conrad, C., Flume, P., Diaz, R., Harris, C., Knowles, M., Cutting, G. R. 2005; 14 (22): 3493-3498

    Abstract

    Cystic fibrosis (CF) is an autosomal recessive disorder of Cl(-) and Na(+) transport. The vast majority of CF patients have deleterious mutations in an epithelial Cl(-) channel called the CF transmembrane conductance regulator (CFTR). In contrast, defects in the epithelial Na(+) channel (SCNN1) have been associated with phenotypes dominated by renal disease (systemic pseudohypoaldosteronism type I and Liddle syndrome). We report two non-classic CF patients without CFTR mutations who have novel deleterious mutations in the beta-subunits of SCNN1 in the absence of overt renal disease.

    View details for DOI 10.1093/hmg/ddi374

    View details for Web of Science ID 000233216600015

    View details for PubMedID 16207733

  • Does bacterial colonization play a role in acute respiratory failure in chronic obstructive pulmonary disease? CRITICAL CARE MEDICINE Conrad, C. 2005; 33 (9): 2130-2131
  • Evaluation of exposure and health care worker response to nebulized administration of tgAAVCF to patients with cystic fibrosis ANNALS OF OCCUPATIONAL HYGIENE Croteau, G. A., Martin, D. B., Camp, J., Yost, M., Conrad, C., Zeitlin, P. L., Heald, A. E. 2004; 48 (8): 673-681

    Abstract

    A study was conducted to assess health care worker exposure to tgAAVCF during the aerosolized administration of this experimental gene transfer agent in clinical trials for the treatment of cystic fibrosis (CF). tgAAVCF is a recombinant adeno-associated virus (AAV) genetically engineered to contain the human CF transmembrane conductance regulator cDNA. Study subjects included eight health care workers involved in the administration of tgAAVCF in a phase II study and 12 control health care workers who were involved with the treatment of CF patients, but not administration of the study drug. The exposure assessment entailed the determination of personal and area airborne tgAAVCF concentrations. In addition, serologic status of the health care workers was evaluated throughout the study for the presence of antibodies to AAV. A symptom survey was also completed by both the active and control health care workers. Air samples were analyzed by an infectivity assay (active vector) and a DNA polymerase chain reaction amplification procedure (vector DNA). Air monitoring was conducted during 13 tgAAVCF and seven placebo administrations. Active vector and vector particles were detected in four of 51 and 48 of 51 air samples collected during the administration of tgAAVCF, respectively. Based on the airborne vector particle concentration, the workers' exposure was estimated to be 0.0006% of the administered dose. At this level of exposure, the prevalence of symptoms was very low, the spectrum was similar in both study groups and did not result in any reported negative health effects.

    View details for Web of Science ID 000225270100003

    View details for PubMedID 15507460

  • Phase I trial of intranasal and endobronchial administration of a recombinant adeno-associated virus serotype 2 (rAAV2)-CFTR vector in adult cystic fibrosis patients: A two-part clinical study HUMAN GENE THERAPY Flotte, T. R., Zeitlin, P. L., Reynolds, T. C., Heald, A. E., Pedersen, P., Beck, S., Conrad, C. K., Brass-Ernst, L., Humphries, M., Sullivan, K., Wetzel, R., Taylor, G., Carter, B. J., Guggino, W. B. 2003; 14 (11): 1079-1088

    Abstract

    Recombinant adeno-associated serotype 2-based vectors (rAAV2) possess a number of theoretical advantages for cystic fibrosis (CF) gene therapy because they elicit little or no inflammatory response and generally result in stable expression. rAAV2 vectors expressing the cystic fibrosis transmembrane conductance regulator (CFTR) gene have previously been shown to mediate stable correction of the CF defect in CF bronchial epithelial cells and stable expression of CFTR in rabbit and nonhuman primate models. Here we report the results of the first trial initiated with rAAV in humans, a phase I study in 25 adult and adolescent CF patients with mild to moderate lung disease. Doses of the rAAV-CFTR vector (tgAAVCF) ranging from 3 x 10(1) to 1 x 10(9) replication units (RU), which is equivalent to approximately 6 x 10(4) to 2 x 10(12) DNase resistant particles (DRP), were administered to one side of the nose and to the superior segment of the lower lobe of the right lung. Several adverse events were noted prior to and/or after vector delivery, but most of them appeared to be related to the endogenous CF lung disease or a result of the bronchoscopic procedures. Only one of the serious events was judged to be possibly vector-related (based on temporal association), and this event was a pulmonary exacerbation very similar to several others experienced by the same subject in the three months preceding vector delivery. Vector shedding was minimal throughout the study, and serum-neutralizing antibodies were detected after vector delivery to subjects in the highest dosage cohorts. Gene transfer as measured by DNA polymerase chain reaction (PCR) was not observed until cohort 10 in nasal and bronchial epithelia. Sporadic low-level copy numbers suggested gene transfer of anywhere from 0.002 copies per cell up to 0.5 copies per cell was possible; however, DNA PCR was positive in lungs prior to direct dosing suggesting aspiration from the nasal dosing. These data indicate the need for continued evaluation of rAAV-CFTR vectors in additional clinical trials.

    View details for Web of Science ID 000184205600004

    View details for PubMedID 12885347

  • A phase II, double-blind, randomized, placebo-controlled clinical trial of tgAAVCF using maxillary sinus delivery in patients with cystic fibrosis with antrostomies HUMAN GENE THERAPY Wagner, J. A., Nepomuceno, I. B., Messner, A. H., Moran, M. L., Batson, E. P., DiMiceli, S., Brown, B. W., Desch, J. K., Norbash, A. M., Conrad, C. K., Guggino, W. B., Flotte, T. R., Wine, J. J., Carter, B. J., Reynolds, T. C., Moss, R. B., Gardner, P. 2002; 13 (11): 1349-1359

    Abstract

    tgAAVCF, an adeno-associated cystic fibrosis transmembrane conductance regulator (CFTR) viral vector/gene construct, was administered to 23 patients in a Phase II, double-blind, randomized, placebo-controlled clinical trial. For each patient, a dose of 100,000 replication units of tgAAVCF was administered to one maxillary sinus, while the contralateral maxillary sinus received a placebo treatment, thereby establishing an inpatient control. Neither the primary efficacy endpoint, defined as the rate of relapse of clinically defined, endoscopically diagnosed recurrent sinusitis, nor several secondary endpoints (sinus transepithelial potential difference [TEPD], histopathology, sinus fluid interleukin [IL]-8 measurements) achieved statistical significance when comparing treated to control sinuses within patients. One secondary endpoint, measurements of the anti-inflammatory cytokine IL-10 in sinus fluid, was significantly (p < 0.03) increased in the tgAAVCF-treated sinus relative to the placebo-treated sinus at day 90 after vector instillation. The tgAAVCF administration was well tolerated, without adverse respiratory events, and there was no evidence of enhanced inflammation in sinus histopathology or alterations in serum-neutralizing antibody titer to adeno-associated virus (AAV) capsid protein after vector administration. In summary, this Phase II trial confirms the safety of tgAAVCF but provides little support of its efficacy in the within-patient controlled sinus study. Various potentially confounding factors are discussed.

    View details for Web of Science ID 000177015400009

    View details for PubMedID 12162817

  • Paradoxical vocal cord motion in a child presenting with cyanosis and respiratory failure. Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies Falco, D. A., Hammer, G. B., Conrad, C., Messner, A. H. 2002; 3 (2): 185-186

    View details for PubMedID 12780992

  • Clinical infection control in gene therapy: A multidisciplinary conference INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY Evans, M. E., Jordan, C. T., Chang, S. M., Conrad, C., Gerberding, J. L., Kaufman, H. L., Mayhall, C. G., Nolta, J. A., Pilaro, A. M., Sullivan, S., Weber, D. J., Wivel, N. A. 2000; 21 (10): 659-673

    Abstract

    Gene therapy is being studied for the treatment of a variety of acquired and inherited disorders. Retroviruses, adenoviruses, poxviruses, adeno-associated viruses, herpesviruses, and others are being engineered to transfer genes into humans. Treatment protocols using recombinant viruses are being introduced into clinical settings. Infection control professionals will be involved in reviewing the safety of these agents in their clinics and hospitals. To date, only a limited number of articles have been written on infection control in gene therapy, and no widely available recommendations exist from federal or private organizations to guide infection control professionals. The goals of the conference were to provide a forum where gene therapy experts could share their perspectives and experience with infection control in gene therapy and to provide an opportunity for newcomers to the field to learn about issues specific to infection control in gene therapy. Recommendations for infection control in gene therapy were proposed.

    View details for Web of Science ID 000089872900011

    View details for PubMedID 11083185

  • A phase I/II study of tgAAV-CF for the treatment of chronic sinusitis in patients with cystic fibrosis HUMAN GENE THERAPY Wagner, J. A., Moran, M. L., Messner, A. H., DAIFUKU, R., Conrad, C. K., Reynolds, T., Guggino, W. B., Moss, R. B., Carter, B. J., Wine, J. J., Flotte, T. R., Gardner, P. 1998; 9 (6): 889-909

    View details for Web of Science ID 000073201700014

    View details for PubMedID 9581911

  • Safety of single-dose administration of an adenoassociated virus (AAV)-CFTR vector in the primate lung GENE THERAPY Conrad, C. K., Allen, S. S., Afione, S. A., Reynolds, T. C., Beck, S. E., FeeMaki, M., BarrazzaOrtiz, X., Adams, R., Askin, F. B., Carter, B. J., Guggino, W. B., Flotte, T. R. 1996; 3 (8): 658-668

    Abstract

    Gene therapy for cystic fibrosis (CF) would ideally be accomplished with a vector capable of long-term expression of the cystic fibrosis transmembrane conductance regulator (CFTR) in the absence of a host inflammatory response. Recombinant adeno-associated virus (AAV)-CFTR vectors possess these characteristics in rabbits. Because the utility of AAV vectors as gene transfer agents has only been recognized recently, AAV vector-mediated transduction has never been modeled in a primate host, which is an important step before its use in humans. In order to test the safety and biological activity of AAV-CFTR, single doses of AAV-CFTR vector were administered by fiberoptic bronchoscopy to the posterior basal segment of the right lower lobe (RLL) of the lungs of 10 rhesus macaques with four matched vehicle-treated controls. Animals were followed for 10, 21, 90 or 180 days following vector instillation. Vector DNA transfer occurred in bronchial epithelial cells in the RLL of each animal that received vector as assessed by in situ DNA PCR. Vector mRNA was detectable for 180 days after administration as detected by RT-PCR and by RNase protection assay. Safety of vector administration was determined by measurements of pulmonary mechanics, arterial blood gas analysis, chest radiographs, and bronchoalveolar lavage (BAL) fluid analysis including cell count and quantification of inflammatory cytokines. Gross and microscopic pathologic examination were also performed. There was no evidence of inflammation or other toxicity, although vector DNA was found in extrapulmonary organs of some animals. These results indicate that transduction of the primate airway epithelium with the AAV-CFTR mediates long-term CFTR cDNA transfer and is relatively safe.

    View details for Web of Science ID A1996VB53600002

    View details for PubMedID 8854091

  • A phase I study of an adeno-associated virus-CFTR gene vector in adult CF patients with mild lung disease HUMAN GENE THERAPY Flotte, T., Carter, B., Conrad, C., Guggino, W., Reynolds, T., Rosenstein, B., Taylor, G., Walden, S., Wetzel, R. 1996; 7 (9): 1145-1159

    View details for Web of Science ID A1996WD31600008

    View details for PubMedID 8773517

  • In vivo model of adeno-associated virus vector persistence and rescue JOURNAL OF VIROLOGY Afione, S. A., Conrad, C. K., Kearns, W. G., Chunduru, S., Adams, R., Reynolds, T. C., Guggino, W. B., Cutting, G. R., Carter, B. J., Flotte, T. R. 1996; 70 (5): 3235-3241

    Abstract

    Gene therapy vectors based on human DNA viruses could be mobilized or rescued from individuals who are subsequently infected with the corresponding wild-type (wt) helper viruses. This phenomenon has been effectively modeled in vitro with both adenovirus (Ad) and adeno-associated virus (AAV) vectors but has not previously been studied in vivo. In the current study, we have developed an in vivo model to study the interactions of a recombinant AAV vector (AAV-CFTR) with wt AAV type 2 (AAV2) and a host range mutant Ad (Ad2HR405) for which monkey cells are permissive (D.E.Brough, S.A.Rice, S.Sell, and D.F.Klessig, J. Virol. 55:206-212, 1985). AAV-CFTR was administered to the respiratory epithelium of the nose or lung of rhesus macaques. Primary cells were harvested from the infusion site at time points up to 3 months after vector administration to confirm vector DNA persistence. Vector DNA was present in episomal form and could be rescued in vitro only by addition of wt AAV2 and Ad. In in vivo rescue studies, vector was administered before or after wt-AAV2 and Ad2HR405 infection, and the shedding of AAV-CFTR was examined. Ad2HR405 and wt-AAV2 infections were established in the nose with concomitant administration. wt-AAV2 replication occurred in the lung when virus was administered directly at a high titer to the lower respiratory tract. AAV-CFTR vector rescue was also observed in the latter setting. Although these studies were performed with small numbers of animals within each group, it appears that AAV-CFTR DNA persists in the primate respiratory tract and that this model may be useful for studies of recombinant AAV vector rescue.

    View details for Web of Science ID A1996UF24700065

    View details for PubMedID 8627804

  • ALVEOLAR STEM-CELL TRANSDUCTION BY AN ADENOASSOCIATED VIRAL VECTOR GENE THERAPY Zeitlin, P. L., Chu, S., Conrad, C., MCVEIGH, U., Ferguson, K., Flotte, T. R., Guggino, W. B. 1995; 2 (9): 623-631

    Abstract

    In inherited disorders such as surfactant protein deficiencies or cystic fibrosis (CF), where lung damage develops progressively after birth, gene replacement is best accomplished in the neonatal period. We use the adeno-associated virus (AAV) as a vector for gene transfer in the newborn rabbit lung where stem cells are activated for lung growth and differentiation. AAV-mediated gene transfer as assayed by lacZ gene expression occurred preferentially in alveoli in the alveolar epithelial progenitor cell, the type II cell, and in the large airway tracheobronchial basal and ciliated cells. Cell proliferation was confirmed by 5-bromo-deoxyuridine (BRDU) labeling in regions undergoing alveolarization and airway branch points. Regions of cell proliferation coincided with areas of significant lacZ expression. Thus, dividing and differentiating cells can be targeted by AAVlacZ delivery to newborn lung.

    View details for Web of Science ID A1995TC43400004

    View details for PubMedID 8548551

  • GENE-THERAPY VECTORS AS DRUG-DELIVERY SYSTEMS CLINICAL PHARMACOKINETICS Afione, S. A., Conrad, C. K., Flotte, T. R. 1995; 28 (3): 181-189

    View details for Web of Science ID A1995QM09300001

    View details for PubMedID 7758249

  • HEMOTHORAX IN A CHILD AS A RESULT OF COSTAL EXOSTOSIS PEDIATRICS TOMARES, S. M., Jabra, A. A., Conrad, C. K., Beauchamp, N., Phoon, C. K., Carroll, J. L. 1994; 93 (3): 523-525

    View details for Web of Science ID A1994MY68700036

    View details for PubMedID 8115223

  • STABLE IN-VIVO EXPRESSION OF THE CYSTIC-FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR WITH AN ADENOASSOCIATED VIRUS VECTOR PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Flotte, T. R., Afione, S. A., Conrad, C., McGrath, S. A., Solow, R., Oka, H., Zeitlin, P. L., Guggino, W. B., Carter, B. J. 1993; 90 (22): 10613-10617

    Abstract

    Adeno-associated virus (AAV) vectors expressing the normal cystic fibrosis transmembrane conductance regulator (CFTR) cDNA complement the cystic fibrosis (CF) defect in vitro. Unlike other DNA virus vectors, AAV is a stably integrating virus, which could make possible long-term in vivo complementation of the CF defect in the airway epithelium. We report AAV-CFTR gene transfer and expression after infection of primary CF nasal polyp cells and after in vivo delivery of AAV-CFTR vector to one lobe of the rabbit lung through a fiberoptic bronchoscope. In the rabbit, vector DNA could be detected in the infected lobe up to 6 months after administration. A 26-amino acid polypeptide sequence unique to the recombinant AAV-CFTR protein was used to generate both oligonucleotide probes and a polyclonal antibody which allowed the unambiguous identification of vector RNA and CFTR protein expression. With these reagents, CFTR RNA and protein were detected in the airway epithelium of the infected lobe for up to 6 months after vector administration. AAV vectors do, therefore, efficiently promote in vivo gene transfer to the airway epithelium which is stable over several months. These findings indicate that AAV-CFTR vectors could potentially be very useful for gene therapy.

    View details for Web of Science ID A1993MH32200042

    View details for PubMedID 7504271

  • PROTEINS BUT NOT AMINO-ACIDS, CARBOHYDRATES, OR FATS STIMULATE CHOLECYSTOKININ SECRETION IN THE RAT AMERICAN JOURNAL OF PHYSIOLOGY Liddle, R. A., Green, G. M., Conrad, C. K., Williams, J. A. 1986; 251 (2): G243-G248

    Abstract

    Because of prior difficulties in measuring plasma cholecystokinin (CCK) levels, it has not been established which components of food stimulate CCK secretion in rats. In the present study, we used a sensitive and specific bioassay for measuring plasma CCK and determined the effects of proteins, protein hydrolysates, amino acids, fats, starch, and glucose on CCK secretion in this species. Intact proteins were the only stimulants of CCK release. Solutions of 18% casein and 0.2% soybean trypsin inhibitor caused prompt increases in plasma CCK levels from 0.5 +/- 0.2 to 7.9 +/- 1.9 and 8.0 +/- 2.0 pM, respectively, within 5 min of orogastric administration. The proteins lactalbumin and bovine serum albumin caused smaller elevations in circulating CCK. In contrast, hydrolysates of casein and lactalbumin and the amino acids L-phenylalanine and L-tryptophan did not stimulate CCK release. In addition, plasma CCK levels did not increase with the feeding of fat, starch, or glucose. The ability of proteins to stimulate CCK secretion paralleled their ability to inhibit trypsin activity in vitro. Furthermore, the plasma CCK response to casein was completely abolished by the simultaneous administration of trypsin. These studies indicate that proteins are the major food stimulants of CCK release in the rat and that the effects of proteins are related to inhibition of intraluminal protease activity.

    View details for Web of Science ID A1986D598500053

    View details for PubMedID 3740265

  • REGULATION OF GASTRIC-EMPTYING IN HUMANS BY CHOLECYSTOKININ JOURNAL OF CLINICAL INVESTIGATION Liddle, R. A., Morita, E. T., Conrad, C. K., Williams, J. A. 1986; 77 (3): 992-996

    Abstract

    In the present study we used a bioassay system for measuring plasma cholecystokinin (CCK) to evaluate whether CCK has a physiologic role in regulating gastric emptying in humans. Plasma CCK levels and gastric emptying after ingestion of a mixed liquid meal were determined in five normal male volunteers. Fasting CCK levels averaged 0.8 +/- 0.1 pM and increased to 6.5 +/- 1.0 pM within 10 min of drinking the mixed meal. CCK levels remained elevated for up to 90 min. Gastric emptying after a meal was slow; at the end of the 90 min 68% of the original volume remained in the stomach. The rate of gastric emptying of water was then measured in the same individuals with a simultaneous infusion of either saline, or one of two doses of CCK (12 pmol/kg per h and 24 pmol/kg per h). With the saline infusion, plasma CCK levels did not increase above basal and gastric contents emptied rapidly. At the end of 90 min only 7% of the original volume remained in the stomach. The lower dose of CCK resulted in a plasma level of 3.4 pM which both reproduced the average postprandial plasma level and caused a significant delay in gastric emptying. The higher dose of CCK achieved plasma levels of 8 pM and resulted in a delay in gastric emptying that was similar to that seen with the mixed meal. Since exogenous CCK at concentrations which occur postprandially delays gastric emptying, we conclude that CCK is a physiologic regulator of gastric emptying.

    View details for Web of Science ID A1986A542900043

    View details for PubMedID 3949984

Conference Proceedings


  • Safety and biological efficacy of an adeno-associated virus vector cystic fibrosis transmembrane regulator (AAV-CFTR) in the cystic fibrosis maxillary sinus Wagner, J. A., Messner, A. H., Moran, M. L., DAIFUKU, R., Kouyama, K., Desch, J. K., Manley, S., Norbash, A. M., Conrad, C. K., Friborg, S., Reynolds, T., Guggino, W. B., Moss, R. B., Carter, B. J., Wine, J. J., Flotte, T. R., Gardner, P. JOHN WILEY & SONS INC. 1999: 266-274

    Abstract

    The host immune response and low vector efficiency have been key impediments to effective cystic fibrosis transmembrane regulator (CFTR) gene transfer for cystic fibrosis (CF). An adeno-associated virus vector (AAV-CFTR) was used in a phase I dose-escalation study to transfer CFTR cDNA into respiratory epithelial cells of the maxillary sinus of 10 CF patients.A prospective, randomized, unblinded, dose-escalation, within-subjects, phase I clinical trial of AAV-CFTR was conducted.Ten patients with previous bilateral maxillary antrostomies were treated.Safety, gene transfer as measured by semiquantitative polymerase chain reaction (PCR), and sinus transepithelial potential difference (TEPD) were measured.The highest level of gene transfer was observed in the range of 0.1-1 AAV-CFTR vector copy per cell in biopsy specimens obtained 2 weeks after treatment. When tested, persistence was observed in one patient for 41 days and in another for 10 weeks. Dose-dependent changes in TEPD responses to pharmacologic intervention were observed following treatments. Little or no inflammatory or immune responses were observed.AAV-CFTR administration to the maxillary sinus results in successful, dose-dependent gene transfer to the maxillary sinus and alterations in sinus TEPD suggestive of a functional effect, with little or no cytopathic or host immune response. Further study is warranted for AAV vectors as they may prove useful for CFTR gene transfer and other in vivo gene transfer therapies. A prospective, randomized, double-blind, placebo-controlled, within-subjects, phase II clinical trial of the effect AAV-CFTR on clinical recurrence of sinusitis will determine the clinical efficacy of AAV gene therapy for CF.

    View details for Web of Science ID 000078432500017

    View details for PubMedID 10890777

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