Systemic haemodynamic changes in patients with cystic fibrosis with and without chronic liver disease

BACKGROUND/AIMS

There are well-documented systemic haemodynamic changes associated with chronic liver disease. Patients with cystic fibrosis may develop chronic liver disease, but it is not known whether these systemic haemodynamic changes develop and, if they do, whether they are influenced by the associated chronic lung disease. We therefore undertook a study to document the circulatory status of cystic fibrosis patients with and without chronic liver disease.

METHODS

Fifty-six subjects with cystic fibrosis were studied. Systemic haemodynamic and pulmonary parameters, in sub-groups both with (LD) and without (NLD) liver disease, were measured at rest and during measured exertion. Cystic fibrosis-related chronic liver disease was diagnosed using previously validated ultrasound criteria. Patients underwent assessment at rest and in the fourth minute of seated bicycle exercise at 25W. Heart rate (ECG), blood pressure (semiautomated sphygmomanometer), aortic blood velocity (pulsed Doppler suprasternal probe), arterial oxygen saturation (pulse oximeter) and respiratory variables (pneumotachometer with expired gas analysis by an automatic system) were measured.

RESULTS

A complete data set was available for 45 patients (22 LD) at rest and 40 patients (19 LD) on exercise. The patients were well matched for age, sex, height, weight, and pulmonary function. Patients with chronic liver disease had a hyperkinetic circulation while ventilatory variables before and during exercise were similar for the two groups. There was evidence that the circulatory changes were exacerbated by both deteriorating hepatic and pulmonary function.

CONCLUSIONS

Cystic fibrosis patients with chronic liver disease have a hyperdynamic circulation similar to that documented in other forms of chronic liver disease. These circulatory changes are exacerbated by deteriorating hepatic and pulmonary function.

Partial resolution of acute interstitial pneumonia in native lung after single lung transplantation

The case of a 49 year old man presenting with rapidly progressive interstitial lung disease is described. Radiological findings and the lung biopsy specimen were compatible with an acute interstitial pneumonia, as was the relentless clinical course culminating in hypoxic respiratory failure. After right single lung transplantation there was considerable improvement in lung function and radiographic clearing of disease in the native left lung.

Trimethoprim and tetracycline inhibit airway epithelial sodium absorption

Despite their frequent use in the treatment of chronic lung disease, the effect of antibiotics on the airway mucosa has not been defined. We have assessed the effect of a number of antibiotics on the ion transport processes of airway epithelia. Initial evaluation performed on sheep tracheal epithelium in vitro demonstrated that trimethoprim and tetracycline induced a rapid decrease in electrogenic ion transport. These responses were fully reversible, mediated through the mucosal surface, and reduced by amiloride pretreatment, suggesting inhibition of Na+ absorption. Serosal application of erythromycin produced a gradual decrease in short-circuit current, whereas other antibiotics (ampicillin, ceftazidime, colistin, chloramphenicol, gentamicin, and sulfamethoxazole) caused no significant change within 30 min of addition. In healthy human volunteers, trimethoprim and tetracycline induced a rapid decrease in nasal potential difference, which was attenuated by amiloride pretreatment. In subjects with cystic fibrosis, who exhibit increased Na+ absorption across respiratory epithelia, the responses to trimethoprim and tetracycline were enhanced, providing further evidence that these drugs inhibit Na+ absorption. In conclusion, this study has identified two antibacterial agents that also reduce the Na+ absorption found in CF. These drugs may offer combined effects for the treatment of CF.

Asthma prophylaxis agents alter the function of an airway epithelial chloride channel

A number of recent observations suggest a link between airway Cl-transport and asthma. We have previously described the properties of a voltage- and Ca2+ -dependent chloride channel present in airway epithelium. We now show that agents able to prevent indirectly induced bronchoconstriction (sodium cromoglycate, nedocromil sodium, and furosemide) reduce either the single-channel conductance or the open probability of this channel. The effects of these agents and the Ca2+ dependence of the channel are localized to the same surface, and we show that the channel possesses a specific divalent cation binding site, which responds to concentrations of Ca2+ found on the airway mucosal surface. No alteration of the single-channel properties of this channel were seen in cystic fibrosis epithelium. These data suggest a mechanism by which structurally diverse agents may influence asthma.

Quantitative fluorescence measurements of chloride secretion in native airway epithelium from CF and non-CF subjects

Functional assessment of the efficacy of CFTR gene transfer protocols in humans has previously involved measurement of in vivo potential difference. We have studied whether freshly obtained airway epithelial cells may provide suitable tissue for studies of in vivo gene transfer using fluorescent digital imaging microscopy. Nasal epithelial cells from non-cystic fibrosis subjects (n = 6) and from cystic fibrosis (CF) patients (delta F508: delta F508, n = 5) were obtained by brushing and loaded with 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ). Addition of the cAMP-agonists forskolin (20 microM) and 3-isobutyl-1-methylxanthine (IBMX, 100 microM) produced an increased efflux of iodide from the cells which was significantly (P < 0.05) greater in non-CF than in CF cells. Efflux following addition of the calcium ionophore, ionomycin (100 microM) was similar in both non-CF and CF cells. Liposome-mediated transfection of CF nasal epithelial cells in vitro with CFTR-cDNA restored the cAMP-stimulated efflux to non-CF values. Bronchial epithelial cells from non-CF subjects showed responses to forskolin and ionomycin that were not different to those in non-CF nasal epithelia. These data demonstrate that the assay provides a useful method for assessing correction of abnormal ion transport in non-cultured CF epithelium and is likely to provide a further assay for assessment of in vivo gene transfer efficiency in protocols of gene therapy for CF.

Home treatment of patients with cystic fibrosis using the 'Intermate': the first year's experience

Home treatment of patients with cystic fibrosis has many attractions and is becoming increasingly popular. The investigators have studied the use, results and costs of the first year of operation of a home-care intravenous antibiotic service using the 'Intermate' infusion device in a prospective study using questionnaires, spirometric and weight measurements. Ninety-three patients received 166 courses of intravenous antibiotics in full or in part at home during 1991. The average length of treatment was 12.5 days and on average 70% of the treatment was given at home. The mean percentage predicted FEV1 and FVC improved after treatment and the mean improvement was not significantly different to that produced by hospital treatment. Breathlessness, sputum volume, appetite, ability to sleep, mood, energy and overall well-being, as assessed by questionnaire, showed significant improvements after home treatment. The median time spent mixing and administering drugs was 10-19 hours and visiting the hospital was 7-12 hours. The median number of days of lost income to patients or their carers was 0 days. The majority of the patients were extremely satisfied with the treatment and supervision that they received. Using the home care service, 1442 inpatient days were saved. The investigators conclude that home care using 'Intermates' improves a patient's lung function and quality of life.

Fatal haemorrhage from mesenchymal cystic hamartoma of the lung

A 34 year old women was admitted to the hospital with a 9 year history of intermittent haemoptysis associated with increasing breathlessness. A working diagnosis of lymphangioleiomyomatosis was made, based on clinical, radiological and histological findings. Three years later, the patient was admitted to hospital with worsening haemoptysis, which rapidly progressed and resulted in death from massive pulmonary haemorrhage. Postmortem examination and histology revealed findings consistent with multiple mesenchymal cystic hamartomas of the lungs. This is a rare condition which has previously been described as having a good prognosis. This case is the first fatality resulting directly from the disease to be reported.

Recall lung pneumonitis due to carmustine after radiotherapy

A patient who developed pneumonitis immediately after the administration of carmustine (BCNU), within exactly the same field as previous irradiation, is presented. The patient responded partially to corticosteroids. This case suggests that irradiation causes subclinical sensitisation of the lung and can therefore have an additive effect in precipitating lung damage when another pulmonary toxin is encountered at a later date.

Gene therapy for alpha 1-antitrypsin deficiency

Alpha 1-antitrypsin deficiency is associated with pulmonary emphysema and liver cirrhosis. The pathogenesis and treatment is reviewed with particular emphasis on gene therapy for emphysema. The technology of gene transfer using viruses and liposomes is developing fast and animal experiments have confirmed the feasibility of gene therapy for alpha 1-antitrypsin deficiency (AATD). So far only subtherapeutic levels of protein have been produced but human trials are starting and progress can be expected.

Two years experience with recombinant human DNase I in the treatment of pulmonary disease in cystic fibrosis

Recombinant human DNase I (rhDNase) has been shown to improve pulmonary function in patients treated for up to 6 months. A cohort of 52 cystic fibrosis patients with a FVC > 40% predicted were enrolled into an open label study in order to evaluate longer-term effects of rhDNase. They received 2.5 mg rhDNase twice daily for 6 months followed by a 2-week wash-out period, and for the subsequent 18 months were treated with rhDNase once daily. Twenty-six male and 26 female patients with a mean FVC of 2.941 and FEV1 of 1.471 were recruited. Thirteen patients did not complete the study; there were seven deaths, three patients withdrew consent and three patients were lost to follow-up. Improvement in pulmonary function was seen following treatment and changes were evaluated as mean percent change from baseline. The maximum improvement occurred in the first month followed by a plateau at a lower level of improvement. The mean improvement in FEV1 over the first month was 13.3% (range 12-14.1%), followed by a plateau at around 7.1% (range 4.6-11.0%) for the subsequent 23 months. Mean FVC was improved by 12.03% (range 9.0-14.3%) over the first month and subsequently 4.2% (range - 2.2-10.2%). The effects on pulmonary function were similar for both treatment doses of rhDNase. There was also a steady improvement in weight from a mean of 54.2 kg to 55.7 kg at the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Recombinant human DNase I in cystic fibrosis patients with severe pulmonary disease: a short-term, double-blind study followed by six months open-label treatment

Chronic pulmonary infection is the major cause of morbidity and mortality in cystic fibrosis (CF). Recombinant human deoxyribonuclease (rhDNase) in vitro has been shown to dramatically reduce the viscoelasticity of the sputum from CF patients. Phase II and III clinical trials have shown the drug to be safe, and that patients with a forced vital capacity (FVC) of > 40% predicted show an improvement in pulmonary function when receiving rhDNase. The current study evaluates the safety and efficacy of rhDNase in the most severly ill CF patients (FVC < 40% predicted). A double-blind, randomized, placebo-controlled trial in which patients received either 2.5 mg rhDNase twice daily or placebo for a period of 14 days followed by a 6 month open extension period (OEP) is reported. Seventy patients were recruited for the double-blind study, and 64 entered the OEP of whom 38 completed. During the OEP, all patients received 2.5 mg rhDNase twice daily. In both the double-blind period and the OEP the drug appeared to be safe. During the double-blind study, forced expiratory volume in one second (FEV1) and FVC improved in both groups but there was no statistically significant difference between the groups. In the OEP, there was mean improvement in percentage predicted FEV1 and FVC, 9 and 18%, respectively, for all patients participating. In conclusion, DNase is safe when administered in conjunction with a rigorous regimen of chest physiotherapy to severely ill patients (FVC < 40% predicted) with CF. The double-blind, 14 day study showed no significant improvement in pulmonary function but some patients may have improved after longer administration of rhDNase.

Recombinant human DNase I in cystic fibrosis patients with severe pulmonary disease: a short-term, double-blind study followed by six months open-label treatment

Chronic pulmonary infection is the major cause of morbidity and mortality in cystic fibrosis (CF). Recombinant human deoxyribonuclease (rhDNase) in vitro has been shown to dramatically reduce the viscoelasticity of the sputum from CF patients. Phase II and III clinical trials have shown the drug to be safe, and that patients with a forced vital capacity (FVC) of > 40% predicted show an improvement in pulmonary function when receiving rhDNase. The current study evaluates the safety and efficacy of rhDNase in the most severly ill CF patients (FVC < 40% predicted). A double-blind, randomized, placebo-controlled trial in which patients received either 2.5 mg rhDNase twice daily or placebo for a period of 14 days followed by a 6 month open extension period (OEP) is reported. Seventy patients were recruited for the double-blind study, and 64 entered the OEP of whom 38 completed. During the OEP, all patients received 2.5 mg rhDNase twice daily. In both the double-blind period and the OEP the drug appeared to be safe. During the double-blind study, forced expiratory volume in one second (FEV1) and FVC improved in both groups but there was no statistically significant difference between the groups. In the OEP, there was mean improvement in percentage predicted FEV1 and FVC, 9 and 18%, respectively, for all patients participating. In conclusion, DNase is safe when administered in conjunction with a rigorous regimen of chest physiotherapy to severely ill patients (FVC < 40% predicted) with CF. The double-blind, 14 day study showed no significant improvement in pulmonary function but some patients may have improved after longer administration of rhDNase.

Medium term treatment of stable stage cystic fibrosis with recombinant human DNase I

BACKGROUND

A phase II multicentre double blind placebo controlled study in 1993 showed that short term treatment (10 days) with recombinant human DNase I (rhDNase) was safe and improved pulmonary function in patients with cystic fibrosis with stable stage lung disease. A six month open label treatment study was conducted in some of the patients who participated in the short term study to assess the medium term effects of rhDNase.

METHODS

Patients who completed the phase II study and were stable for 14 days prior to treatment were eligible. They were treated with rhDNase 2.5 mg twice daily for six months and reviewed at regular intervals to assess safety and efficacy.

RESULTS

Fifty nine patients (31M,28F) of age range 16-55 years were recruited. Mean baseline values for forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were 41.5% and 72.4% of predicted, respectively. The mean increase in FEV1 over the first month of treatment was 13.1% (range 12-14.1%) and then stabilised at 6.2% (4.6-7.8%) for the subsequent five months. FVC was similarly improved. Administration of rhDNase improved the severity of dyspnoea, cystic fibrosis related symptoms, and the modified Taussig/NIH score (not statistically significant). Fifty seven of the 59 patients completed the study; two died from progression of their pulmonary disease unrelated to treatment with rhDNase. The adverse events and intercurrent illnesses were no different from those expected in a cystic fibrosis population. Pharyngitis was the only possible drug related adverse event which occurred at least once in 14% of patients during the six month period.

CONCLUSIONS

Administration of rhDNase was safe, well tolerated, and improved pulmonary function in patients with cystic fibrosis. When rhDNase was stopped at day 169 there was a deterioration in pulmonary function and dyspnoea score.

Gene therapy for cystic fibrosis: a clinical perspective

Since the isolation of the cystic fibrosis (CF) gene in 1989, the potential for gene therapy for this disease has existed. Although current treatments have resulted in a mean life expectancy of approximately 30 years, there is clearly a need for more effective therapy. A large number of studies have now assessed both in vitro and in vivo CFTR gene transfer into cell lines, animal models and most recently in CF subjects. Despite this rapid progress several difficulties remain including efficient in vivo gene transfer and the measurement of end-points to assess such gene transfer. This article reviews some of the clinically related aspects of gene therapy for CF.

Bioelectric characteristics of exon 10 insertional cystic fibrosis mouse: comparison with humans

Two important issues that can be addressed by animal models are disease pathogenesis and the testing of new treatments, including gene therapy. How closely these models mimic the relevant disorder in humans will determine their usefulness. This study examines how closely the characteristic bioelectric features of cystic fibrosis (CF) are reproduced in the airways and intestinal tract of the exon 10 insertional mutant mouse (cf/cf). In agreement with CF subjects these cf/cf mutant mice demonstrate the following: 1) reduced adenosine 3',5'-cyclic monophosphate-related chloride secretion throughout the respiratory and intestinal tracts both in vivo and in vitro, 2) calcium-related chloride secretion that is preserved in the airways but reduced in the intestine, and 3) a more negative nasal potential difference and increased amiloride response compared with wild-type animals, likely to relate to increased sodium absorption. In contrast to humans, sodium absorption is not increased in the small intestine and is reduced in the trachea of the cf/cf mice. We conclude that the majority of the salient electrophysiological features of CF required for studies of pathogenesis or testing of new treatments are present in these cf/cf mice.

Lack of inhibition by dideoxy-forskolin and verapamil of DIDS-sensitive volume-activated Cl- secretion in human squamous lung carcinoma epithelial cells

The effect of osmotic stress on Cl- permeability in human squamous lung carcinoma epithelial (S1) cells was investigated using a macroscopic 125I efflux assay. Hypotonic challenge of monolayers led to a significant (P < 0.01) dose-related increase in efflux from pre-loaded cells, returning to pre-activation rates within 10 min. A similar magnitude of response could be produced by challenge with an isotonic low chloride-containing solution. Neither 100 mM dideoxy-forskolin nor 100 mM verapamil inhibited the increase in Cl- secretion after hypotonic challenge, whereas 100 mM DIDS inhibited volume-activated Cl- secretion by 55%. Both Northern and Western blot analysis confirmed the absence of MDR1 mRNA and P-glycoprotein in the S1 cells. We conclude that these cells have a volume-regulated Cl- secretory pathway that is independent of the ABC transporter, P-glycoprotein.