Genetic modifiers of liver disease in cystic fibrosis.

CONTEXT: A subset (approximately 3%-5%) of patients with cystic fibrosis (CF) develops severe liver disease with portal hypertension. OBJECTIVE: To assess whether any of 9 polymorphisms in 5 candidate genes (alpha(1)-antitrypsin or alpha(1)-antiprotease [SERPINA1], angiotensin-converting enzyme [ACE], glutathione S-transferase [GSTP1], mannose-binding lectin 2 [MBL2], and transforming growth factor beta1 [TGFB1]) are associated with severe liver disease in patients with CF. DESIGN, SETTING, AND PARTICIPANTS: Two-stage case-control study enrolling patients with CF and severe liver disease with portal hypertension (CFLD) from 63 CF centers in the United States as well as 32 in Canada and 18 outside of North America, with the University of North Carolina at Chapel Hill as the coordinating site. In the initial study, 124 patients with CFLD (enrolled January 1999-December 2004) and 843 control patients without CFLD were studied by genotyping 9 polymorphisms in 5 genes previously studied as modifiers of liver disease in CF. In the second stage, the SERPINA1 Z allele and TGFB1 codon 10 genotype were tested in an additional 136 patients with CFLD (enrolled January 2005-February 2007) and 1088 with no CFLD. MAIN OUTCOME MEASURES: Differences in distribution of genotypes in patients with CFLD vs patients without CFLD. RESULTS: The initial study showed CFLD to be associated with the SERPINA1 Z allele (odds ratio [OR], 4.72; 95% confidence interval [CI], 2.31-9.61; P = 3.3 x 10(-6)) and with TGFB1 codon 10 CC genotype (OR, 1.53; 95% CI, 1.16-2.03; P = 2.8 x 10(-3)). In the replication study, CFLD was associated with the SERPINA1 Z allele (OR, 3.42; 95% CI, 1.54-7.59; P = 1.4 x 10(-3)) but not with TGFB1 codon 10. A combined analysis of the initial and replication studies by logistic regression showed CFLD to be associated with SERPINA1 Z allele (OR, 5.04; 95% CI, 2.88-8.83; P = 1.5 x 10(-8)). CONCLUSIONS: The SERPINA1 Z allele is a risk factor for liver disease in CF. Patients who carry the Z allele are at greater risk (OR, approximately 5) of developing severe liver disease with portal hypertension.

Long-acting bronchodilators in cystic fibrosis.

PURPOSE OF REVIEW: Over 80% of patients with cystic fibrosis (CF) have bronchodilator therapy prescribed, yet bronchodilator use in CF remains controversial. The development of long-acting beta-agonist drugs for clinical use has provided additional rationale for considering bronchodilator therapy in CF. This paper will review recent developments in bronchodilator use in CF patients, with emphasis on the long-acting beta agonists. RECENT FINDINGS: It is reported that 50 to 60% of CF patients demonstrate significant intermittent airway hyperreactivity in response to bronchodilators or challenges. The beta-agonist drugs are the most commonly prescribed bronchodilators. Several mechanisms may be implicated in therapeutic response of CF patients to bronchodilators including direct smooth muscle relaxation, increased mucociliary clearance, direct effects on inflammatory cells and bacterial adherence, and possible direct effects on CF transmembrane conductance regulator (CFTR) function. Several recent studies have shown improved outcomes with long-acting bronchodilators. SUMMARY: In spite of the widespread use of bronchodilators, there are very few long-term studies of their effects in CF patients. However, there are clearly clinical benefits in certain situations. Further research into the most appropriate utilization of these medications to improve outcomes in patients with CF would be helpful.

Effectiveness and tolerability of high-dose salmeterol in cystic fibrosis.

The efficacy and tolerability of high-dose salmeterol (100 mcg, BID) and albuterol (2.5 mg, BID) were compared with those of albuterol (2.5 mg, BID) in outpatients with cystic fibrosis in a randomized, double-blind, double-dummy, placebo-controlled, crossover study with both short- (4 weeks of each) and long-term (24 weeks of each) treatment periods. The primary outcome measure was the difference in mean change in forced expired volume in 1 sec (FEV(1)) from baseline to the end of each treatment, and secondary measures included changes in forced vital capacity (FVC), forced expiratory flow between 25-75% of FVC (FEF(25-75)), patient-rated weekly symptom scores, number of extra (rescue) albuterol treatments, and number of antibiotic treatments. Tolerability was evaluated by changes in vital signs and adverse events.Thirty-six out of 44 patients enrolled finished the short-term treatment period, and 19 out of 23 who continued the study also finished the long-term treatment period. There was no significant difference in the mean % change in FEV(1) from baseline to completion of 4 weeks with each drug in the short-term treatment period (0.1% vs. 0.06%, albuterol vs. salmeterol; respectively). In the long-term treatment period, there was a significant decrease from baseline in FEV(1) with albuterol vs. salmeterol, as measured after both 12 and 24 weeks of each treatment (-6.2% vs. 1.8%, P = 0.013 after 12 weeks, and -6.5% vs. 1.7%, P = 0.002, after 24 weeks, respectively). In both treatment periods, salmeterol was well-tolerated. While there were more rescue treatments per patient per week with albuterol than with salmeterol treatment in both the short- and long-term periods (0.67 vs. 0.40 and 1.76 vs. 0.74, respectively), rescue treatments were needed significantly more often for only the long-term period with albuterol compared to salmeterol (P = 0.022). Also, there were more antibiotic interventions with albuterol than with salmeterol treatment in both the short- and long-term periods (25 vs. 10 and 56 vs. 42, respectively); however, antibiotics were needed significantly more often for only the short-term period (P = 0.011). In addition, there was a significantly higher symptom score with albuterol vs. salmeterol treatment during the second half of the long-term period (1.24 vs. 0.89, P = 0.001).In conclusion, long-term high-dose salmeterol was equally safe and was associated with better pulmonary function, fewer interventions, and fewer respiratory symptoms compared to standard therapy with albuterol in a population of outpatients with mild to moderate CF.