Changes in fecal microbiota with CFTR modulator therapy: A pilot study.

Studies have demonstrated that people with CF with pancreatic insufficiency (PI) have fecal dysbioses. Evidence suggests the causes of these dysbioses are multifactorial, and that important drivers include antibiotic exposure, dietary intake, and CF gastrointestinal tract dysfunction, including nutrient malabsorption. In this pilot study, we tested whether initiation of the CFTR modulator treatments ivacaftor (in a cohort of pancreatic sufficient (PS) people with CF and an R117H CFTR variant) or lumacaftor/ivacaftor (in a cohort of PI people with CF and an F508del variant) changed fecal measures of malabsorption or fecal microbiomes. While we identified no statistically significant fecal changes with either treatment, we detected trends in the PI cohort when initiating lumacaftor/ivacaftor towards decreased fecal fat content and towards fecal microbiomes that more closely resembled the fecal microbiota of people without PI. While these findings support a model in which nutrient malabsorption resulting from CF-induced PI drives fecal dysbiosis, they must be validated in future, larger studies of fecal microbiome and malabsorption outcomes with highly effective CFTR modulator therapies.

Repeat administration of an adenovirus vector encoding cystic fibrosis transmembrane conductance regulator to the nasal epithelium of patients with cystic fibrosis.

Cystic fibrosis (CF) is a common autosomal recessive disease caused by mutations in the CF transmembrane conductance regulator gene. Recombinant adenoviruses have shown promise as vectors for transfer of CF transmembrane conductance regulator cDNA to airway epithelia and correction of the Cl- transport defect. However, because adenovirus-mediated gene transfer is transient, use of adenovirus as a vector for treatment of CF would require repeated administration. Therefore, we evaluated repeat administration of an adenovirus vector to the nasal epithelium of patients with CF with five escalating doses of up to 10(10) infectious units. There were no detectable adverse affects. All subjects were initially seropositive but developed additional humoral immune responses. The vector partially corrected the defect in airway epithelial Cl- transport in some subjects, although there was variability between subjects and there was less correction with subsequent administration, perhaps because the immune response limited gene transfer. Future work must focus on vectors with increased efficiency and with the ability to evade host defenses.

Retroviral vectors efficiently transduce basal and secretory airway epithelial cells in vitro resulting in persistent gene expression in organotypic culture.

Gene therapy of the lung requires the introduction and expression of a therapeutic gene in airway cells. Although retroviral vectors may be useful in this context, the ability of retroviruses to infect specific cell types in the airway is not known. In this study, we examined the ability of amphotropic recombinant retroviral vectors to transduce primary cultures of rabbit airway epithelial cell populations purified for basal or secretory cells. Transduction efficiencies in basal and secretory cell populations were found to be similar; about 27% after a single exposure to vector, and up to 77% after multiple exposures. The fate of genetically modified cells from the different populations was followed through terminal differentiation using organotypic cultures. The epithelium of the organotypic cultures generated from each population exhibited both pseudostratified and stratified morphology, produced mucin, and stained positively with antibodies specific for basal and ciliated cells. The mucociliary epithelium also showed co-localization of these phenotypic markers with the expression of the vector-encoded beta-galactosidase gene. We conclude that retroviruses can efficiently transduce primary cultures of basal and secretory cells, and that both of these cell types can be progenitor cells of the airway epithelium. In vivo delivery of a retroviral vector containing a human placental alkaline phosphatase gene resulted in expression of the heterologous gene in rabbit tracheal epithelial cells. However, transduction efficiency was low and occurred only in the wounded trachea.

A phase I study of aerosolized administration of tgAAVCF to cystic fibrosis subjects with mild lung disease.

Cystic fibrosis (CF) is one of the most common autosomal recessive disorders in North America, leading to significant morbidity and early mortality. The defect in the cystic fibrosis transmembrane conductance regulator protein (CFTR) function can be corrected in vitro by gene replacement with a wild-type gene. A Phase I, single administration, dose escalation trial was designed and executed to assess safety and delivery of tgAAVCF, an adeno-associated virus (AAV) vector encoding the human CFTR cDNA, by nebulization to the lungs of CF subjects. Four cohorts of three subjects each were administered increasing doses of the study agent, beginning with 10(10) DNase-resistant particles (DRP) and escalating in log increments up to 10(13) DRP. Sequential bronchoscopies were performed to gather analytical samples throughout the study. All 12 subjects completed the study. There were a total of 242 adverse events (AEs), six of which were defined as serious and three of which were defined as possibly being related to the study drug. A clear dose-response relationship was observed in vector gene transfer. A maximum of 0.6 and 0.1 vector copies per brushed cell were observed 14 days and 30 days, respectively, following nebulization of 10(13) DRP tgAAVCF, and this declined to nearly undetectable levels by day 90. Vector gene transfer was evenly distributed throughout the fourth airway generation following single-dose administration. RNA-specific PCR did not detect vector-derived mRNA. This Phase I trial shows that aerosolized tgAAVCF is safe and widely delivered to the proximal airways of CF subjects by nebulization.

Disposition of drugs in cystic fibrosis. V. In vivo CYP2C9 activity as probed by (S)-warfarin is not enhanced in cystic fibrosis.

Enhanced metabolism of theophylline in subjects with cystic fibrosis suggests that the activity of certain cytochrome P450 isoforms is affected in subjects with this genetic disease. To determine whether this effect on the P450 enzymes is selective, the in vivo activity of the cytochrome P450 isoform CYP2C9 was determined in adult subjects with cystic fibrosis (n = 6) and in control subjects (n = 8). Subjects were administered (S)-warfarin as a single intravenous bolus dose (0.375 mg/kg), and urine and plasma samples were collected for 96 hours. Plasma (S)-warfarin concentrations were determined by HPLC; urinary concentrations of (S)-warfarin and its metabolites were determined by gas chromatography-mass spectrometry. The total plasma clearance of (S)-warfarin (subjects with cystic fibrosis, 3.6 +/- 0.48 ml/hr/kg; control subjects, 3.82 +/- 0.73 ml/hr/kg), elimination half-life (subjects with cystic fibrosis, 29.5 +/- 4.2 hours; control subjects, 25.9 +/- 5.4 hours); and steady-state volume of distribution (subjects with cystic fibrosis, 153 +/- 18 ml/kg; control subjects, 138 +/- 22 ml/kg) were similar in the two groups (p > 0.05). The metabolic clearance of (S)-warfarin to its major metabolites mediated by CYP2C9, 6-hydroxywarfarin and 7-hydroxywarfarin, was not significantly (p > 0.05) different between the two groups (6-hydroxywarfarin: subjects with cystic fibrosis, 0.33 +/- 0.1 ml/hr/kg; control subjects, 0.41 +/- 0.1 ml/hr/kg; 7-hydroxywarfarin: subjects with cystic fibrosis, 1.34 +/- 0.49 ml/hr/kg; control subjects, 1.8 +/- 0.45 ml/hr/kg). On the basis of these data, we conclude that the in vivo cytochrome P450 activity is selectively affected in persons with cystic fibrosis.

Disposition of drugs in cystic fibrosis. III. Acetaminophen.

The disposition of acetaminophen after oral administration was investigated in adults with cystic fibrosis (n = 5) and in age-matched healthy control subjects (n = 5). The total plasma clearance of acetaminophen was found to be greater (p less than 0.025) in subjects with cystic fibrosis (0.362 +/- 0.081 L/hr/kg) than in control subjects (0.247 +/- 0.022 L/hr/kg). This difference in clearance was found to be primarily attributable to a greater metabolic clearance of acetaminophen to acetaminophen sulfate (0.080 +/- 0.023 L/hr/kg for subjects with cystic fibrosis and 0.045 +/- 0.008 L/hr/kg for control subjects; p less than 0.05) and to a greater metabolic clearance of acetaminophen to acetaminophen glucuronide (0.189 +/- 0.051 L/hr/kg for subjects with cystic fibrosis and 0.114 +/- 0.017 L/hr/kg for control subjects; p less than 0.05) in persons with cystic fibrosis. Of the mechanisms that may be responsible for these differences, the most likely is enhanced activity (in subjects with cystic fibrosis) of the transferases that mediate the metabolism of acetaminophen to acetaminophen sulfate and acetaminophen glucuronide, respectively.

New and emerging therapies for pulmonary complications of cystic fibrosis.

In the decade since the gene for cystic fibrosis (CF) was discovered, research into potential therapeutic interventions has progressed on a number of different fronts. The vast majority of morbidity and mortality in CF results from inflammation and infection of the airways. Direct delivery of antibacterials to the airway secretions via a nebuliser is an attractive therapeutic option, and a novel formulation of tobramycin designed for such a purpose has been demonstrated to improve spirometry and decrease the need for intravenous antibacterials. In addition, early clinical trials are studying the effects of small peptides with antibiotic properties (defensins) delivered directly to the airways. Inflammation, whether secondary to infection or an independent feature of CF, leads to progressive bronchiectasis. Anti-inflammatories such as prednisone and possibly ibuprofen have been shown to decrease the rate of respiratory decline in patients with CF but have tolerability profiles that limit clinical usefulness. Macrolides also have anti-inflammatory properties and clinical trials are now ongoing to assess the efficacy of these agents in CF. Multiple agents, including uridine triphosphate (UTP), genistein, phenylbutyrate and CPX (cyclopentyl dipropylxanthine), have been demonstrated in cell culture to at least partially correct the primary defect of ion transport related to mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). No agent of this class has yet demonstrated clinical effectiveness, but several are in preclinical and early clinical trials. Finally, gene therapy that allows for the incorporation and expression of wild-type CFTR in respiratory epithelial cells would be definitive therapy for CF. However, multiple barriers to delivery and expression need to be overcome. With research proceeding on these multiple fronts, new therapies for pulmonary complications promise to continue to increase the life expectancy of individuals with CF.

Unusual presentation of recurrent Wegener's granulomatosis.

A 65-year-old woman presented with recurrent Wegener's granulomatosis following two years of immunosuppressive therapy and three years of complete remission. At her initial presentation, she had a characteristic x-ray picture showing multiple nodules with total resolution of these findings at three months. Five years later, at the time of clinical relapse, her chest x-ray film showed bilateral diffuse infiltrative disease. This change in radiologic presentation upon relapse of Wegener's has not previously been reported. Other unusual features include diffuse infiltrates as the pulmonary presentation and the long interval between cessation of therapy and relapse. We review the radiologic manifestations of Wegener's granulomatosis.

Life-threatening theophylline toxicity is not predictable by serum levels.

We questioned whether there was any way to predict which patients with high serum theophylline levels would develop life-threatening toxicity and thereby determine which patients might benefit from prophylactic therapeutic measures, such as hemoperfusion or hemodialysis. We reviewed the records of 54 consecutive patients seen over a five-year period in whom the serum theophylline level was 39 micrograms/ml or higher (range 39-78 micrograms/ml, mean theophylline level 49.5 +/- 9.6 micrograms/ml). Toxicity sought included cardiovascular--major arrhythmias (asystole, ventricular tachycardia, ventricular fibrillation) and minor arrhythmias, (central nervous system--major [seizures], minor [confusion, agitation]); and gastrointestinal (nausea, vomiting and diarrhea). In our sample of patients with extremely high theophylline levels, the incidence of life-threatening complications was low, and the subgroup of patients with high serum theophylline levels who developed life-threatening toxicity could not be easily identified. We conclude that major interventional procedures such as hemoperfusion or hemodialysis should not be used prophylactically in this population of patients of middle age to elderly men with high theophylline levels. We recommend a more conservative approach of using oral activated charcoal therapy in all patients with high serum theophylline levels, and reserving hemoperfusion or hemodialysis for those patients who develop seizures or major arrhythmias.

Complications of indwelling catheters in cystic fibrosis: a 10-year review.

STUDY OBJECTIVE: Patients with cystic fibrosis (CF) frequently require recurrent courses of IV antibiotics to treat acute exacerbations of their pulmonary disease. Over time, CF patients often lose peripheral access, and indwelling central venous catheters are placed. We attempted to determine the type and incidence of catheter complications so that CF patients could be fully informed of the risks prior to placement of these catheters. DESIGN: The charts of all CF patients who attended the Adult Cystic Fibrosis Clinic of the University of Washington Medical Center from January 1989 through December 1998 were reviewed. Demographic information was obtained along with the type and duration of catheter, type and number of complications, and the use of anticoagulant medication. MEASUREMENTS AND RESULTS: Of the 218 CF patients who attended the clinic, 65 patients (30%) had indwelling catheters in place at some time during the study period. A total of 87 catheters were placed into these 65 patients. The total number of catheter-days for first indwelling catheters was 68,220. The total number of catheter-days for all catheters was 75,660 (210 catheter-years). Thirty-five catheter-related complications were identified, occurring in 26 patients. Complications included thrombosis (n = 14), infections (n = 9), mechanical problems (n = 6), pneumothorax (n = 3), superior vena cava syndrome/stenosis (n = 2), and air embolism (n = 1), for an overall complication rate of 0. 463/1,000 catheter-days. CONCLUSION: We conclude that indwelling catheters are relatively safe in patients with CF. Good infection control policies appear to prevent most infectious complications. The most common complication is that of thrombosis, which may be recurrent in some patients. Consideration should be given to prophylactic warfarin therapy despite the potential risk of significant hemoptysis in this patient population.

Variable severity of pulmonary disease in adults with identical cystic fibrosis mutations.

Adults with CF followed in a university center were assessed for the presence of the most common CF gene mutation, delta-F508. Excluding one member of a sibling pair, 29 of 55 subjects had two copies of delta-F508 (homozygotes), 23 had one copy of delta-F508 with the other CF mutation not identified (complex heterozygotes) and three were lacking delta-F508. A wide range of clinical severity was seen among individuals carrying two copies of the delta-F508 gene, who are genetically identical at the CF gene locus. The number of individuals diagnosed with CF as adults was significantly lower in the homozygote group (1 of 29) as compared with the heterozygote group (7 of 24). No differences were detected between groups in pulmonary function, non-pulmonary complications or overall clinical severity. These results suggest that environmental or background genetic factors contribute significantly to the variability in pulmonary and other complications seen among individuals with CF.

Cardiac asystole during an hypoxic drive study in a normal subject.

A healthy 31-year-old man who had previously sojourned to an altitude of 5,000 meters with no detrimental effect developed sudden cardiac asystole during a progressive hypoxic ventilatory response ( HVR ) test. At the moment of asystole, his alveolar PO2 (PAO2) was 41 mm Hg and his arterial oxygen saturation (SaO2) was 81 percent. Cardiopulmonary resuscitation was initiated, and after 20 seconds of asystole and apnea, he recovered normal sinus rhythm and spontaneous respiration. A subsequent ECG and cardiac enzyme levels were normal. During testing, he demonstrated depressed ventilation in response to hypoxia and a slowing of the heart rate. Careful observation of heart rate and breath-by-breath ventilation during HVR tests may predict this potentially fatal complication.

Nontuberculous mycobacterial disease in adult cystic fibrosis patients.

This study was conducted to determine the prevalence of mycobacterial disease in an adult cystic fibrosis (CF) population and to determine if there were any patients at higher risk for this disease within the group. Sixty-four patients (28 women, 36 men), ranging in age from 17 to 50 years were screened. One-step purified protein derivative skin testing with controls was performed and sputum was taken for examination. Eight of 64 had positive sputum culture for nontuberculous Mycobacterium. The CF patients with positive mycobacterial sputum cultures tended to be older and to have lower clinical scores than those who did not have Mycobacterium organisms in sputum. Guidelines to determine whether mycobacterial disease or colonization is present should be pursued for the CF population.

Prevalence of allergic bronchopulmonary aspergillosis and atopy in adult patients with cystic fibrosis.

BACKGROUND: Underestimation of allergic bronchopulmonary aspergillosis (ABPA) prevalence in the cystic fibrosis (CF) population is suspected due to nonuniform diagnostic criteria, nonspecific signs and symptoms, assessment during asymptomatic intervals, and physician nonaggressiveness in making the diagnosis. OBJECTIVE: To define the prevalence of ABPA in adult patients with CF, as the increased duration of bronchiectasis may increase the probability of Aspergillus fumigatus (Af) colonization. We also sought to determine whether atopy increases the prevalence of ABPA in adults with CF. METHODS: We examined a cross-sectional population of adult patients with CF at the University of Washington for 1 year. RESULTS: Information was collected on 53 of 65 (82%) patients. Fifteen of 51 (29%) had an immediate skin test reaction to Af, and 30 of 51 (59%) had at least one positive skin test. Increased total serum IgE (>450 IU/mL) was present in 0 of 53; increased IgE-Af and IgG-Af were found in 12 of 53 (23%) and 9 of 53 (17%), respectively; 24 of 53 (45%) had Af-precipitins. Peripheral blood eosinophilia was present in one patient. Eight of 49 (16%) patients' sputum cultures grew Af. ABPA-CB (ABPA-central bronchiectasis) was present in one patient and ABPA-S (ABPA-seropositive) in no patients. Atopy was present in 20 of 51 (39%). CONCLUSION: There was a low prevalence of ABPA in the adult CF population despite frequent immunologic responses to Af. The prevalence of ABPA was too small to determine an association with atopy.

Successful lung transplantation in spite of cystic fibrosis-associated liver disease: a case series.

Lung transplantation has recently offered hope for prolonged survival in patients with cystic fibrosis. Patients with cystic fibrosis have a 7% prevalence of associated liver disease and portal hypertension. These patients have been previously excluded from consideration for lung transplantation. The natural history of cystic fibrosis-associated liver disease suggests a benign and protracted course in most cases. At the University of Washington, 14 of 53 patients (26%) have undergone lung transplantation for cystic fibrosis-related respiratory failure. We report the outcome of double lung transplantation in four of these 14 patients who also had cystic fibrosis-associated liver disease and portal hypertension, all of whom were symptom free from their liver disease. All four patients are alive and well without complications 4 to 31 months after transplantation. We conclude that the presence of cystic fibrosis-associated liver disease with portal hypertension, in the setting of good synthetic function (albumin > 3.0 gm/L and normal prothrombin time), normal serum bilirubin, minimal varices, without ascites or encephalopathy, should not be an absolute contraindication to lung transplantation. We recommend that other transplantation centers also include this patient population in consideration for lung transplantation.

Influence of body size and gender on control of ventilation.

Hypoxic (HVR) and hypercapnic (HCVR) ventilatory responses are influenced by both metabolic activity and hormonal factors. By studying 67 subjects of both sexes, including those at the extremes of stature, we examined the influence of gender, CO2 production (VCO2), O2 consumption (VO2), body surface area (BSA), and vital capacity (VC) on resting ventilation (VE), HVR, and HCVR. We measured resting VE, VO2, and VCO2 and then performed isocapnic progressive hypoxic and hypercapnic ventilatory responses. The effect of stature was reflected in higher VE and metabolic rate (both P less than 0.001) in tall men compared with short men that was ablated by correction for BSA. Perhaps because their heights vary less than those of the men, tall women were not statistically distinguishable from short women in any of these measured parameters. Tall men tended to have greater hypoxic chemosensitivity than short men but this was not significantly different (P = 0.07). Gender affected the control of ventilation in a number of ways. Men had higher VE (P less than 0.05) and metabolic rate (P less than 0.001) than women. Even after correction for BSA men still had higher metabolic rates. Women had higher VE/VCO2 than men (P less than 0.05) and lower resting end-tidal Pco2 (PETCO2) values (P less than 0.05). Both A, the shape parameter of the hyperbolic HVR curve, and HVR determined from mouth occlusion pressure (AP) were greater in women than in men, although only AP reached statistical significance. However, corrections of A for BSA (P less than 0.05), VCO2 (P less than 0.01), and VC (P less than 0.001) amplified these differences.(ABSTRACT TRUNCATED AT 250 WORDS)

Osteoporosis in patients with cystic fibrosis.

Decreased bone density and increased risk of fractures are seen in patients with cystic fibrosis. Suboptimal vitamin D levels, nutrition problems, hypogonadism, inactivity, corticosteroid use, and cytokines may contribute to the low bone mass seen in these patients. Treatment recommendations must be individualized and may include nutrition, vitamin D, estrogen or testosterone, and exercise. In high-risk patients calcitonin or growth hormone could be considered.

Pseudomonal pericarditis complicating cystic fibrosis.

Patients with advanced cystic fibrosis typically have chronic bacterial infection of the upper and lower respiratory tracts, but rarely develop extrapulmonary sites of infection. We report a case of purulent pericarditis due to Pseudomonas aeruginosa in a patient with cystic fibrosis and no other risk factors for pericarditis. This is a previously unreported complication in cystic fibrosis prior to lung transplantation.

Sensation of smell does not determine nutritional status in patients with cystic fibrosis.

Poor nutritional status in patients with cystic fibrosis (CF) is associated with increased mortality. Patients with CF often have a decreased sensation of smell secondary to recurrent sinus infections or sinus surgery; in other CF populations, a decreased sensation of smell has been associated with poor nutritional status. We hypothesized that a decreased sensation of smell would be associated with worse nutritional status in patients with CF. We studied 50 (26 F and 24 M) of 58 consecutive patients with CF (86%) aged 14-53 years (28 +/- 8; mean +/- SD) who attended the University of Washington Medical Center from June 1994 to March 1995 and who agreed to participate. Demographic information was obtained, and nutritional status was assessed by ideal body weight, arm muscle area, arm fat area, pancreatic sufficiency, insulin-requiring diabetes, vitamins A and E levels, albumin, iron, iron binding capacity, ferritin, cholesterol, and zinc levels. Objective sensation of small was examined (Sensonics, Philadelphia, PA), a sinus compacted tomogram (CT) was performed, and a questionnaire for prior sinus symptoms, sinus surgery, medications, and subjective sensation of smell was administered. Twenty-seven of 49 subjects (55%) had an objective decrease in sensation of smell, 23/50 (46%) had had prior sinus surgery. 46/50 (92%) were pancreatic insufficient, and 8/50 (16%) were insulin-requiring diabetics. Weight for height ranged from the 38th to 157th percentile (100 +/- 18; mean +/- SD). Arm muscle area ranged from the < 5th to the 75th percentile (25 +/- 23; mean +/- SD). Arm fat area ranged from the < 5th to the 95th percentile (45 +/- 39; mean +/- SD). Sinus CT scans were abnormal in all patients (100%). Patients with anosmia were more likely to have had sinus surgery, but their nutritional status was no different from that of patients with a normal sensation of smell. We conclude that decreased sensation of smell is common in patients with CF, especially those with prior sinus surgery. Subjective sensation of smell and sinus CT scans were unreliable indicators of a decreased objective sensation of smell. In this pilot study, no association was found between sensation of smell and nutritional status.