Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Respiratory manifestations may be secondary to inflammation in cystic fibrosis patients

30.07.2003


New Evidence That Inflammation For Cystic Fibrosis May Be Present Before Patients Show Respiratory Manifestations.

A new study also provides additional evidence that the persistent and excessive inflammation in the lungs of CF patients involves a failure of the mechanisms that control the inflammatory response.

Cystic Fibrosis (CF) is one of the most frequent lethal chromosomal hereditary disorders in Caucasian populations and occurs in approximately one in every 3,500 births. Caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, a defective cAMP-dependent chloride ion conductance occurs. In patients with CF, lung disease is the major cause of sickness and death with the progressive decline of pulmonary function attributed to a vicious cycle of airway infection and inflammation. There is now evidence that inflammation plays a pivotal role and may be present very early in life, even before the onset of respiratory manifestations.



Background

The inflammatory process in the CF lung is dominated by a polymorphonuclear neutrophil (white blood cell) influx. Accumulation of neutrophils in the airways is associated with high concentrations of neutrophil-derived mediators, in particular pro-inflammatory cytokines (proteins) such as IL-8 and TNF-. Neutrophils also release numerous toxic agents, e.g., proteases and reactive oxygen species, which contribute to the damage of lung tissue. If the consequences of the neutrophil-dominated inflammation in CF with an altered repair of the respiratory structures can be explained by an overwhelming neutrophil toxicity, the mechanisms leading to neutrophil accumulation and activation in the CF airways are poorly understood. One possibility is that pro-inflammatory and anti-inflammatory imbalance with excessive concentrations of the neutrophil chemotactic cytokine IL-8 certainly plays an important role in the influx of neutrophils in the inflamed airways. Locally, bacterial toxins and inflammatory mediators can directly activate the neutrophils to carry out their cytotoxic activities.

Another cause may be that in CF patients, impaired neutrophil functions may contribute to an abnormal release of inflammatory mediators. One recent research effort provided data suggesting that myeloperoxidase-dependent oxygenation activities are altered in blood neutrophils from CF heterozygotes and homozygotes.

A New Study

In considering a CF child’s airway, it is unclear whether the excessive presence of neutrophils is solely a consequence of an increased influx of these cells, or whether it is associated with a cellular dysfunction. Researchers from France studied the capacity of neutrophils to release the major neutrophil pro- and anti-inflammatory cytokines, respectively, IL-8 and IL-1-receptor antagonist (ra). They compared the production of these molecules by neutrophils isolated from the sputum and from the blood of children with CF. The capacity of neutrophils from CF children to release IL-8 and IL-1ra was also compared with cytokine production by blood neutrophils obtained from control subjects and by airway neutrophils obtained from children with chronic pulmonary disease related to dyskinetic cilia syndrome (chronic dilation of the bronchia). Finally, an assessment of the response of airways and blood neutrophils to the anti-inflammatory action of dexamethasone was performed.

The authors of “Distinct Cytokine Production by Lung and Blood Neutrophils from Children with Cystic Fibrosis” are Harriet Corvol, Katarina Chadelat, Jacky Jacquot, Olivier Tabary, Michele Boule’, and Annick Clement’, all from the Departement de Pneumologie Pediatrique-Institut National de la Santé et de la Recherche Médicale, Hopital Armand Trousseau; and Jean-Marc Cavaillon and Catherine Fitting, both from the Unite Postulante Cytokines and Inflammation, Institut Pasteur; all in Paris, France. Their findings appear in the June 2003 edition of the American Journal of Physiology – Lung Cellular and Molecular Physiology.

Methodology

The CF population included 15 children, seven boys and eight girls (mean age: 12.6 ± 0.4 years). Cytokine production by blood neutrophils from CF patients was compared with control subjects, five healthy young adults (mean age: 30.8 ± 3.2 years) from the medical staff without history of lung disease and with normal lung function and four children, two boys and two girls (mean age: 11 ± 0.5 years) with dyskinetic cilia syndrome.

The experiment consisted of: (1) isolation of neutrophils in blood samples; (2) isolation of neutrophils in sputum samples; (3) neutrophil cultures analyzed with lipopolysaccharide (LPS); and (4) measurement of cytokine concentrations.

Results

Key findings from this research showed that:

  • comparison of cytokine production by blood neutrophils from CF patients and from control subjects showed significantly increased IL-8 and decreased IL-1ra release by CF neutrophils;

  • comparison of cytokine production by airway and blood neutrophils from CF patients also documented distinct profiles: the spontaneous release of IL-8 and IL-1ra by airway neutrophils was significantly higher than that from blood neutrophils;

  • culture in the presence of LPS failed to further enhance cytokine production;

  • analysis of the effect of dexamethasone confirmed the difference in the responsiveness of lung and blood neutrophils in CF. Used at a concentration effective in reducing IL-8 production by blood neutrophils, dexamethasone (106 M) was unable to repress secretion of IL-8 by airway neutrophils.

  • In addition, comparison of cytokine production by airway neutrophils from children with CF and children with dyskinetic cilia syndrome also documented distinct profiles of secretion.

Conclusions

These results are consistent with a dysregulated cytokine production by lung and blood neutrophils in CF. They provide support to the hypothesis that not only the CF genotype but also the local environment may modify the functional properties of the neutrophils.

This study is the first report comparing airway and blood neutrophils from children with CF in terms of pro- and anti-inflammatory cytokine production and their respective responsiveness to glucocorticoids. Comparison of airway and blood neutrophils from the same CF patients showed distinct profiles of cytokine production spontaneously and in the presence of LPS, as well as differences in the response to dexamethasone, supporting the view that the local environment may modify the functional properties of the cells. In addition, comparisons of cytokine production by circulating neutrophils from children with CF and controls and by airway neutrophils from children with CF or dyskinetic cilia syndrome revealed significant differences, suggesting that genetic components may also participate in the altered neutrophil function in CF.

The findings provide additional evidence that the persistent and excessive inflammation in the lungs of CF patients involves a failure of the mechanisms that control the inflammatory response. An altered regulation of cytokine production by neutrophils is certainly an important factor that promotes continued inflammation and injury. Development of therapeutic interventions with specific cytokine inhibitors, anti-inflammatory cytokines, as well as anti-inflammatory drugs, which could target airway neutrophils, appears essential to control CF inflammation.

Donna Krupa | American Physiological Society
Further information:
http://www.the-aps.org

More articles from Studies and Analyses:

nachricht Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>