Cystic fibrosis in adolescents and adults. The coming of age of cystic fibrosis

Optimization of a Yellow fluorescent protein-based iodide influx high-throughput screening assay for cystic fibrosis transmembrane conductance regulator (CFTR) modulators

Cystic fibrosis is an inherited, life-threatening disease associated with mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The most common mutation, F508del CFTR, is found in 90% of CF patients. The loss of a single amino acid (phenylalanine at position 508) results in malformed CFTR with defective trafficking to the plasma membrane and impaired channel function. A functional assay with cells expressing F508del CFTR has been previously described by others using genetically engineered halide-sensitive yellow fluorescent protein to screen for CFTR modulators. We adapted this yellow fluorescent protein assay to 384-well plate format with a high-throughput screening plate reader, and optimized the assay in terms of data quality, resolution, and throughput, with target-specific protocols. The optimized assay was validated with reference compounds from cystic fibrosis foundation therapeutics. On the basis of the Z-factor range (≥0.5) and the potential productivity, this assay is well suited for high-throughput screening. It was successfully used to screen for active single agent and synergistic combinations of single agent modulators of F508del CFTR from a library collection of current active pharmaceutical ingredients (supported by Cystic Fibrosis Foundation Therapeutics).

Cystic fibrosis and the transition to adulthood

Cystic fibrosis (CF) has long been thought of as a childhood disease but the life expectancy for those with CF has been steadily on the rise and now reaches well into adulthood. There has been little or no research on the psychosocial impact of CF on becoming an adult. This exploratory, qualitative study examined the perceptions of young adults with CF regarding the impact the disease has had on their lives, especially during the transition from adolescence to adulthood. The findings indicate concerns about health insurance and finances, as well as the achievement of independence and optimism for the future.

Postural drainage and gastro-oesophageal reflux in infants with cystic fibrosis

Gastro-oesophageal reflux is increased in cystic fibrosis and it is possible that postural drainage techniques may exacerbate reflux, potentially resulting in aspiration and further impairment of pulmonary function.

AIM

To evaluate the effects of physiotherapy with head down tilt (standard physiotherapy, SPT) on gastroesophageal reflux and to compare this with physiotherapy without head down tilt (modified physiotherapy, MPT).

METHOD

Twenty (mean age 2.1 months) infants with cystic fibrosis underwent 30 hour oesophageal pH monitoring during which SPT and MPT were carried out for two sessions each on consecutive days.

RESULTS

The number of reflux episodes per hour, but not their duration, was significantly increased during SPT compared with MPT (SPT 2.5 (0.4) v MPT 1.6 (0.3), p = 0.007) and to background (1.1 (0.)1, p = 0.0005). Fractional reflux time was also increased during SPT (11.7 (2.6)%) compared with background (6.9 (1.3)%) p = 0.03) but not compared with MPT (10.7 (2.7)%). There was no significant difference between MPT and background for number of reflux episodes, their duration, or fractional reflux time.

CONCLUSIONS

SPT, but not MPT, was associated with a significant increase in gastro-oesophageal reflux in infants with cystic fibrosis.

High resolution computed tomography in cystic fibrosis: correlation with pulmonary function and assessment of prognostic value

OBJECTIVE

To assess the correlation between HRCT and pulmonary function in patients with CF. Further, to assess the prognostic value of HRCT in these patients.

SUBJECTS AND METHODS

Clinical examination, chest radiographs and HRCT scans on 30 CF patients with an average age of 17 were scored using established scoring systems. The results were correlated with FEV1 and FVC both at time of CT scanning and after 30 months. Results were also correlated with the clinical progress of the patients over the follow-up period.

RESULTS

HRCT, chest radiograph and clinical examination demonstrated similar correlation (p < 0.001) with FEV1 and FVC at the time of scanning. HRCT demonstrated the closest correlation with the clinical progress of the patients over the follow-up period and with follow-up pulmonary function. A maximum combined score for bronchiectasis and emphysema on HRCT seemed to indicate a poor prognosis.

CONCLUSION

HRCT in CF patients correlates well with pulmonary function at time of scanning and at follow-up, and with clinical progress. There may be a role for CT in the identification of adolescent/adult patients who can be expected to need aggressive therapy in the future.

Human biliary epithelial cell line Mz-ChA-1 expresses new isoforms of calmodulin-dependent protein kinase II

BACKGROUND & AIMS

Calmodulin-dependent protein kinase II is a family of closely related multimeric enzymes that regulate a wide variety of cellular processes. In biliary epithelial cells, this kinase seems to regulate Ca(2+)-dependent CI- currents. The aim of this study was to identify isoforms of this kinase expressed in biliary cells.

METHODS

Sequencing of reverse-transcription polymerase chain reaction products identified multiple isoforms in Mz-ChA-1 cells.

RESULTS

Two previously identified isoforms (gamma B and gamma C) and three new isoforms (gamma D, gamma E, and gamma F) of calmodulin-dependent protein kinase II were identified. Each of the novel isoforms contains a unique insert of 114 base pairs in the association region. This insert lies outside the previously identified variable region. In addition, gamma D and gamma F contained other deletions (42 and 69 base pairs, respectively) in the variable region. These isoforms are expressed in a variety of tissues, including biliary epithelial and gallbladder cells, but only gamma C is expressed in rat hepatocytes.

CONCLUSIONS

Identification of these biliary kinase isoforms paves the way for future studies that will elucidate the role of individual isozymes in agonist-stimulated biliary Cl- and fluid secretion.