The 6-minute walk test predicts mortality in a pulmonary nontuberculous mycobacteria-predominant bronchiectasis cohort.

BACKGROUND: Bronchiectasis is a chronic lung condition frequently associated with nontuberculous mycobacteria pulmonary (NTM) disease. Persons with these conditions are at increased risk of mortality. Patient reported outcome (PRO) instruments and the 6-minute walk test (6MWT) have been shown to predict mortality for several lung conditions, but these measures have not been fully evaluated for bronchiectasis and NTM. METHODS: We conducted a retrospective cohort study among adult patients enrolled in a natural history study of bronchiectasis at the National Heart, Lung, and Blood Institute. Electronic medical records were queried for demographic, clinical, microbiologic, radiographic, and PRO instrument data: St. George's Respiratory Questionnaire (SGRQ), Medical Research Council Dyspnea Scale, and the Pulmonary Symptom Severity Score (PSSS). The study baseline date was defined as the patient's first visit after January 1st, 2015 with a SGRQ or 6MWT completed. Follow-up was defined as the interval between the study baseline visit and date of death or December 31st, 2019. Sex-stratified Cox proportional-hazards regression was conducted to identify predictors of mortality. Separate models were run for each PRO and 6MWT measure, controlling for age, body mass index (BMI), fibrocavitary disease status, and M. abscessus infection. RESULTS: In multivariable Cox proportional-hazards regression models, the PSSS-severity (aHR 1.29, 95% CI 1.04-1.59), the 6MWT total distance walked (aHR 0.938, 95% CI 0.896-0.981) and distance saturation product (aHR 0.930, 95% CI 0.887-0.974) independently predicted mortality. In addition, BMI was significantly predictive of mortality in all models. CONCLUSIONS: The 6MWT and a PRO instrument capturing symptom severity are independently predictive of mortality in our cohort of bronchiectasis patients.

Dysregulated Airway Host Defense in Hyper IgE Syndrome due to STAT3 Mutations.

Rationale: Hyper IgE syndrome (STAT3-HIES), also known as Job's syndrome, is a rare immunodeficiency disease typically caused by dominant-negative STAT3 mutations. STAT3-HIES syndrome is characterized by chronic pulmonary infection and inflammation, suggesting impairment of pulmonary innate host defense. Objectives: To identify airway epithelial host defense defects consequent to STAT3 mutations that, in addition to reported mutant STAT3 immunologic abnormalities, produce pulmonary infection. Methods: STAT3-HIES sputum was evaluated for biochemical/biophysical properties. STAT3-HIES excised lungs were harvested for histology; bronchial brush samples were collected for RNA sequencing and in vitro culture. A STAT3-HIES-specific mutation (R382W), expressed by lentiviruses, and a STAT3 knockout, generated by CRISPR/Cas9, were maintained in normal human bronchial epithelia under basal or inflammatory (IL1ß) conditions. Effects of STAT3 deficiency on transcriptomics, and epithelial ion channel, secretory, antimicrobial, and ciliary functions were assessed. Measurements and Main Results: Mucus concentrations and viscoelasticity were increased in STAT3-HIES sputum. STAT3-HIES excised lungs exhibited mucus obstruction and elevated IL1ß expression. STAT3 deficiency impaired CFTR-dependent fluid and mucin secretion, inhibited expression of antimicrobial peptides, cytokines, and chemokines, and acidified airway surface liquid at baseline and post-IL1ß exposure in vitro. Notably, mutant STAT3 suppressed IL1R1 expression. STAT3 mutations also inhibited ciliogenesis in vivo and impaired mucociliary transport in vitro, a process mediated via HES6 suppression. Administration of a γ-secretase inhibitor increased HES6 expression and improved ciliogenesis in STAT3 R382W mutant cells. Conclusions: STAT3 dysfunction leads to multi-component defects in airway epithelial innate defense, which, in conjunction with STAT3-HIES immune deficiency, contributes to chronic pulmonary infection.

Antibacterial activity of high-dose nitric oxide against pulmonary Mycobacterium abscessus disease.

INTRODUCTION: Mycobacterium abscessus is an emerging pulmonary pathogen with limited treatment options. Nitric oxide (NO) demonstrates antibacterial activity against various bacterial species, including mycobacteria. In this study, we evaluated the effect of adjunctive inhaled NO therapy, using a novel NO generator, in a CF patient with pulmonary M. abscessus disease, and examined heterogeneity of response to NO in vitro. METHODS: In the compassionate-use treatment, a 24-year-old CF patient with pulmonary M. abscessus was treated with two courses of adjunctive intermittent NO, first at 160 p.p.m. for 21 days and subsequently by escalating the dose up to 240 p.p.m. for 8 days. Methemoglobin, pulmonary function, 6 min walk distance (6MWD), qualify of life and sputum microbiology were assessed. In vitro susceptibility tests were performed against patient's isolate and comparison clinical isolates and quantified by Hill's slopes calculated from time-kill curves. RESULTS: M. abscessus lung infection eradication was not achieved, but improvements in selected qualify of life domains, lung function and 6MWD were observed during the study. Inhaled NO was well tolerated at 160 p.p.m. Dosing at 240 p.p.m. was stopped due to adverse symptoms, although methemoglobin levels remained within safety thresholds. In vitro susceptibility tests showed a dose-dependent NO effect on M. abscessus susceptibility and significant heterogeneity in response between M. abscessus clinical isolates. The patient's isolate was found to be the least susceptible strain in vitro. CONCLUSION: These results demonstrate heterogeneity in M. abscessus susceptibility to NO and suggest that longer treatment regimens could be required to see the reduction or eradication of more resistant pulmonary strains.

Apoptotic abnormalities in differential gene expression in peripheral blood mononuclear cells from children with Fabry disease.

AIM: This study was designed to examine the effect of enzyme replacement therapy (ERT) on differential gene expression in peripheral blood mononuclear cells (PBMCs) of children with Fabry disease who had not previously been exposed to ERT. METHODS: Thirteen children with Fabry disease (age range, 6.5-17.0 years) were studied as part of a 6-month, open-label study of ERT with agalsidase alfa. Paired blood samples were taken at the start of the study and after 6 months of ERT. Further blood samples were also taken from 16 age-matched control subjects. PBMCs were isolated and, following RNA extraction, differential gene expression analysis was performed using the Human Genome U133 Plus 2.0 microarray. RESULTS: Twenty-one genes were determined to be differentially expressed in PBMCs of ERT-naïve children with Fabry disease compared with healthy controls; neuronal apoptosis inhibitory protein ranked as the most significantly differentially expressed gene. Comparison of gene expression in children with Fabry disease prior to and after ERT showed that two genes were significantly differentially expressed (p < or = 0.05) following treatment; the expressed sequence tag (probe set ID, 243259_at) was downregulated, while expression of apoptosis-inducing factor was increased, possibly as an antioxidant counter-regulatory response. CONCLUSION: This study identifies a number of genes that are differentially expressed in a small cohort of children with Fabry disease relative to healthy controls. These genes may relate to the underlying biological abnormalities in Fabry disease.

Lack of susceptibility of cells from patients with Fabry disease to productive infection with R5 human immunodeficiency virus.

A lack of viral replication after HIV-1Ba-L (R5) but not HIV-1IIIB (X4) infection was found using in-vitro activated peripheral blood-derived mononuclear cells from patients with Fabry disease, who have a defect in the catabolism of globotriaosylceramide. CCR5, but not CD4 or CXCR4 expression levels, were lower and the surface expression of globotriaosylceramide was negligible on activated patients' cells. Our findings suggest a novel resistance mechanism to productive infection with R5 HIV-1 that potentially involves abnormal globotriaosylceramide catabolism.

Weekly enzyme replacement therapy may slow decline of renal function in patients with Fabry disease who are on long-term biweekly dosing.

This study was performed to determine whether adult male patients with Fabry disease who demonstrate a continuing decline in renal function despite 2 to 4 yr of conventionally dosed agalsidase alfa therapy (0.2 mg/kg every other week [EOW]) show an improved slope of decline with weekly administration using the same dosage. Eleven (27%) of 41 adult male patients with Fabry disease who participated in long-term agalsidase alfa clinical trials and who had demonstrated a slope of decline in estimated GFR (eGFR) of > or =5 ml/min per 1.73 m(2)/yr while receiving long-term treatment with agalsidase alfa at the currently recommended dosage of 0.2 mg/kg, infused EOW, were enrolled in this open-label, prospective study. Patients were switched from EOW to weekly infusions and followed for an additional 24 mo. Before switching to weekly dosing, eGFR was 53.7 +/- 6.3 ml/min per 1.73 m(2) (mean +/- SEM), and mean rate of change in eGFR was -8.0 +/- 0.8 ml/min per 1.73 m(2)/yr. During the 24-mo follow-up period after switching to weekly dosing, the mean rate of change in eGFR was observed to slow to -3.3 +/- 1.4 ml/min/1.73 m(2)/yr (P = 0.01 versus EOW). After switching to weekly dosing, three patients demonstrated an improvement in eGFR and six patients demonstrated a slowing in the rate of eGFR decline; only two patients failed to improve their eGFR slope. A multiple regression model confirmed that the weekly infusion regimen was the strongest explanatory variable for the change in eGFR (P = 0.0008), with a weaker contribution from the concomitant use of angiotensin converting enzyme inhibitors/angiotensin receptor blockers (P = 0.02). These results suggest that weekly infusions of agalsidase alfa at a dosage of 0.2 mg/kg may be beneficial in the subgroup of patients who have Fabry disease and whose kidney function continues to decline after 2 to 4 yr or more of standard EOW dosing.

Proteomics of specific treatment-related alterations in Fabry disease: a strategy to identify biological abnormalities.

Fabry disease is inherited as an X-linked disorder secondary to deficiency of alpha-galactosidase A, resulting in abnormal metabolism of substances containing alpha-d-galactosyl moieties. As a consequence, a multisystem disorder develops, culminating in strokes, progressive renal, and cardiac dysfunction. Signs and symptoms of Fabry disease become manifest in childhood, but diagnosis is often delayed. Thirteen children with Fabry disease (age range, 6.5-17 years) were studied as part of a 6-month open-label study of enzyme replacement therapy (ERT) with agalsidase alfa. Paired serum samples were drawn at the start of the study and after 6 months of ERT. Global protein changes in paired samples were compared by using differential stable isotope labeling of peptide lysine residues with O-methylisourea and subsequent nanoHPLC-tandem MS. Statistically significant decreases were observed for five proteins following ERT: alpha(2)-HS glycoprotein, vitamin D-binding protein, transferrin, Ig-alpha-2 C chain, and alpha-2-antiplasmin. The presence of low levels of alpha-2-antiplasmin and plasminogen was confirmed by alternate means in 34 consecutive patients, including four of five ERT-naïve subjects. Decreased alpha-2-antiplasmin was associated with a parallel increase in circulating VEGF. Soluble VEGF receptor-2 was significantly elevated in plasma of patients compared with pediatric controls and decreased with ERT. These results suggest previously unknown abnormalities of fibrinolysis and angiogenesis factors in Fabry disease. We demonstrated the feasibility of identifying treatment-specific alterations in a small number of subjects that point to previously unsuspected disease-related biological abnormalities.

Quantitative dysmorphology assessment in Fabry disease.

PURPOSE: 1) To identify morphometric characteristics in hemizygous patients with Fabry disease a treatable lysosomal storage disorder caused by the deficiency of alpha-galactosidase A where morphological abnormalities have occasionally been mentioned, but have never been investigated systematically. 2) To devise a quantitative method to evaluate dysmorphic abnormalities in Fabry disease. METHOD: Cross-sectional, single center, independent dysmorphology assessment by a panel of three clinical geneticists, based on standardized medical photography. POPULATION: consecutive hemizygous patients with Fabry disease (N = 38) unselected for the features assessed, mean age 38 +/- 10.8 years (range: 10-60), recruited for neuropathic pain into enzyme replacement therapy trials. RESULTS: The following dysmorphic features were identified (in order of descending frequency): periorbital fullness, prominent lobules of the ears, bushy eyebrows, recessed forehead, pronounced nasal angle, generous nose/bulbous nasal tip, prominent supraorbital ridges, shallow midface, full lips, prominent nasal bridge, broad alar base, coarse features, posteriorly rotated ears, and prognathism. Extremity features included broad fingertips, short fingers, prominent superficial vessels of hands, 5 digit brachydactyly, and 5 digit clinodactyly. Narrow anterior-posterior chest diameter was noted. Ten core features were statistically defined. Cronbach's alpha measuring internal consistency was 0.62. Light's kappa for global inter-rater variability was 0.26 while Cohen's kappa allowing pair-wise rater comparison varied between 0.08-0.48. CONCLUSIONS: Patients with Fabry disease share common morphological characteristics of the face, trunk, and extremities. Some of these features are subtle as documented by the inter-rater variability. Awareness of these features may facilitate the diagnosis of patients with Fabry disease, and identification of affected family members.

Enzyme-replacement therapy with agalsidase alfa in children with Fabry disease.

CONTEXT: Fabry disease is an X-linked multisystem disorder. Enzyme-replacement therapy in adults has limited efficacy in treating major sequelae of advanced Fabry disease, such as kidney failure or stroke. This prompted a study of the safety and efficacy of enzyme replacement at an earlier stage of Fabry disease. OBJECTIVES: Our purpose with this work was to evaluate safety and to explore efficacy of enzyme treatment with agalsidase alfa in pediatric patients with Fabry disease. METHODS: We conducted a 6-month open-label study at 3 tertiary care centers with 24 children (19 boys and 5 girls) with a mean age of 11.8 (range: 6.5-18) years, to examine safety parameters, including infusion reactions and antiagalsidase alfa antibodies. RESULTS: Agalsidase alfa was well tolerated, and all of the patients completed the study. Six boys and 1 girl had mild-to-moderate infusion reactions. One boy developed transient immunoglobulin G antibodies against agalsidase alfa. The boys showed a significant reduction in plasma globotriaosylceramide on treatment. Mean estimated glomerular filtration rate, cardiac structure, and function were normal and did not change over 26 weeks. Heart rate variability, as determined by 2-hour ambulatory monitoring, was decreased in the boys compared with the girls at baseline. All indices of heart rate variability improved significantly in the boys. Three patients with anhidrosis, as determined by quantitative sudomotor axon reflex testing, developed sweating. Six of 11 patients could reduce or cease their use of antineuropathic analgesics. CONCLUSIONS: Enzyme replacement with agalsidase alfa was safe in this study. The exploratory efficacy analysis documented increased clearance of globotriaosylceramide and improvement of autonomic function. Prospective long-term studies are needed to assess whether enzyme replacement initiated early in patients with Fabry disease is able to prevent major organ failure in adulthood.

Pediatric Fabry disease.

BACKGROUND: Fabry disease is an underdiagnosed, treatable, X-linked, multisystem disorder. OBJECTIVES: To test the hypothesis that quality of life and sweating are decreased among pediatric patients with Fabry disease, compared with control subjects, and to provide quantitative natural history data and novel clinical end points for therapeutic trials. DESIGN: Prospective, cross-sectional, observational study. SETTING: Referral to the National Institutes of Health. PARTICIPANTS: Twenty-five male children with Fabry disease (mean age: 12.3 +/- 3.5 years) and 21 age-matched control subjects. MAIN OUTCOME MEASURES: Quality of life (measured with the Child Health Questionnaire) and sweating (assessed with the quantitative sudomotor axon reflex test). RESULTS: Quality of life scores for pediatric patients <10 years of age with Fabry disease, compared with published normative values, were 55 +/- 17 vs 83 +/- 19 for bodily pain and 62 +/- 19 vs 80 +/- 13 for mental health. Bodily pain scores for patients > or =10 years of age were 54 +/- 22 vs 74 +/- 23. Sweat volume in the Fabry disease group was 0.41 +/- 0.46 microL/mm2, compared with 0.65 +/- 0.44 microL/mm2 in the control group. Renal function, urinary protein excretion, and cardiac function and structure were normal for the majority of patients. The 3 patients with residual alpha-galactosidase A activity > or =1.5% of normal values were free of cornea verticillata and had normal serum and urinary globotriaosylceramide levels. All other children had glycolipid levels comparable to those of adult patients with Fabry disease. Acroparesthesia and cardiac abnormalities were generally present before anhidrosis and proteinuria. Mapping of the missense mutations on the crystallographic structure of alpha-galactosidase A revealed that the mutations were partially surface-exposed and distal to the active site among individuals with residual enzyme activity. Mutations associated with left ventricular hypertrophy (defined as left ventricular mass index of >51 g/m2.7) were localized near the catalytic site of the enzyme. CONCLUSIONS: Despite the absence of major organ dysfunction, Fabry disease demonstrates significant morbidity already in childhood. We have identified important, potentially correctable or preventable, outcome measures for future therapeutic trials. Prevention of complications involving major organs should be the goal for long-term specific therapy.