cystic fibrosis: from the gene to the disease · cystic fibrosis: milestones •1938 « cystic...

Cystic fibrosis: From the gene to the disease

Christiane Knoop, MD, PhDInstitut de Mucoviscidose de l’ULB –

Hôpital Erasme

[email protected]

Cystic fibrosis

« The infant that tastes of salt will surely die. »

Ancient European saying

Cystic fibrosis: milestones

•1938 « Cystic fibrosis of the pancreas » = mucous plugs in

pancreas of infants dying of malnutrition (Andersen)

•‘40-50 « Mucoviscidosis » = failure to thrive, pulmonary

disease and histological thick inspissated mucous in ≠glands

•1948 Discovery of the basic physiologic defect (di

Sant’Agnese, New York heat wave)

•1983 Identification of the fundamental defect,

the defective chloride transport (Quinton)

•1985 Localization of CF defect on chromosome 7 (Tsui)

•1989 Identification of the gene …

The CFTR gene

4Adapted from S Donaldson Plenary Session NACFC 2013

Tsui, Collins, Riordan

CF: the basic defect

… which encodes for a protein, the

Cystic Fibrosis Transmembrane Conductance Regulator (CFTR),

- a c-AMP regulated chloride channel

- a regulatory protein for other

conductances

Rowe et al. N Engl J Med 2005;352:1992.

Hypothesized Structure of CFTR

MSD =membrane-spanningdomain

NBD = Nucleotide-bindingdomain

R = Regulatory protein

Cl-


Categories of CFTR Mutations

10 non-CFTR genetic polymorphismsstudied, e.g. ACE, αααα1-antiprotease,IL-10, MBL, NOS, TGFββββ, TNFαααα

CF: Incidence

• Inheritance by simple Mendelianautosomal recessive fashion

• Incidence in – Caucasians 1:3200– African-Americans 1:15000– African-Asians 1:31000

• Healthy carrier 1/25

CF in Belgium

11RBM-BMR Draft Report 2011

Registre Belge de la Mucoviscidose (RBM-BMR) – Annual Data Report 2005

CF: Diagnosis

• Evidence of Cl- channel dysfunction (sweat Cl-

≥ 60 mEq/L or NPD consistent with CF)

+• Family history of CF or

• Sino-pulmonary disease or

• Evidence of pancreatic insufficiency

• Genotyping http://www.genet.sickkids.on.ca

Rowe S et al. N Engl J Med 2005;352:1992-2001

Mechanism Underlying Elevated Sodium Chloride Levels in the Sweat of Patients with Cystic Fibrosis


CF sweat duct


Models Explaining the Transepithelial Potential Difference across the Airway Epithelium in Cystic Fibrosis

Excessive function of Na channels, non-CFTR Cl uptake = relative increase in NaCl absorption, deshydratation

Decreased Cl absorption, decreased NaCl absorption

Cystic fibrosis

« There is widespread agreement that defects in ion transport, salt

homeostasis, or both are intimately linked to organ damage in CF.

The precise molecular basis for this connection, however, is unknown. »

Cystic fibrosis: clinical presentation

175th South Eastern European Cystic Fibrosis Conference

CF Lung disease

•Broncho-pulmonary disease

– Bronchiectasis

– ABPA– PNO– Massive hemoptysis


Pseudomonas aeruginosa: wild and mucoid type

Pathogenesis

Defective CF gene

Defective / Deficient CFTR

Decreased Cl secretionIncreased Na absorption

Bronchial obstruction

Infection

Inflammation

Bronchiectasis

Therapeutic approaches

Gene therapy

Activation of mutant CFTRProtein replacement Rx

Cl channel activatorsNa channel blockers

Airway clearance RxBronchodilators, Mucolytics

Vaccines / AntibioticsAZM

Anti-inflammatory agents

Lung transplantation

Adapted from Davis and Konstan NACFC 2004

Respiratory complications

� Allergic broncho-pulmonary

aspergillosis (ABPA)

� Pneumothorax

� Hemoptysis


ABPA: Pathogenesis

� Aspergillus widely distributed fungus

� Sensitization to inhaled Asp antigens

� Allergic inflammatory response


ABPA: Diagnosis

1. Asthma

2. New pulmonary infiltrates

3. Immediate skin reactivity to Asp ag

4. Total IgE > 417 IU/ml

5. Serum ↓↓↓↓ ab against Asp

6. Central bronchiectasis

7. Peripheral blood eosinophilia

8. Elevated IgE/IgG against AF


ABPA and CF

ABPA: Treatment strategies

� Oral corticosteroids

+/- anti-fungal treatment• Itraconazole

• Voriconazole

� Alternatives:• Steroid pulses

� Anti-IgE antibodies (Omalizumab)• Add-on treatment

ABPA and CF

Pneumothorax: Hospital admission ?

� Small PNO may be observed in the out-patient setting

- asympytomatic- symptomatic ?

� Large PNO = admission

Flume et al. Am J Respir Crit Care Med 2010; 182: 298-306

Pneumothorax: Chest tube ?

� Large PNO – Unstable YES

– Stable YES

� Small PNO – Unstable YES

– Stable NO



Pneumothorax: Pleurodesis ?

� First PNO NO

� Recurrent PNO depends– Large ipsilateral YES

– Small ipsilateral ?

� Preferred method: • Surgical pleurodesis: thoracoscopy/tomy

• 2nd choice chemical pleurodesis

• Do not compromise future LTx


Pneumothorax: Airway clearance techniques

PEP and IP percussion to be withheldFlume et al. Am J Respir Crit Care Med 2010; 182: 298-306

Pneumothorax: Aerosol therapy


Hemoptysis: Pathogenesis (Hypothesis !)

� Persistent airway inflammation � Angiogenesis →→→→ dilatation of bronchial arteries� Systemic pressure � Proximity of bronchi and bronchiectasies � Damage to vessel walls by acute, recurrent andchronic inflammation / infection

� Episodic / recurrent / persistent bleeding intovessel lumen

� Hemoptysis

Minor hemoptysis

� Contributing causes:• Chronic infection

• Vitamine K deficiency

• Platelet dysfunction

• Thrombocytopenia > hypersplenism

� Adults > children

� Common

� > 9% patients in 5-yr interval

Massive hemoptysis

� > 250 ml / 24 h � Causes:

• Structural anomalies of the bronchi and lung• Chronic infection• Vitamine K deficiency• Platelet dysfunction• Thrombocytopenia > hypersplenism

� Adults > children � Average annual incidence 0.85%� 1/115 CF patients per year� 4.1% patients in their lifetime

Hemoptysis: Management

� Contact doctor ?• Scant < 5 ml ?, 1st episode ever

• Mild > 5 ml Yes

• Massive Absolutely

� Hospital admission ?• Scant No (?)

• …

• Massive Absolutely


Hemoptysis: Airway clearance techniques

Scant hemorrhage go onModerate ?Massive stop all ACT, clot mobilization ?Flume et al. Am J Respir Crit Care Med 2010; 182: 298-306

Hemoptysis: Aerosol therapy

Scant go onModerate go onMassive: stop hypertonic saline, DNAse ?Flume et al. Am J Respir Crit Care Med 2010; 182: 298-306

Hemoptysis: Bronchial artery embolization ?

� Massive, unstable: Yes

� Massive and stable: ?

� Bronchoscopy before BAE: NO

� Embolize bleeding vessel or all

abnormal vessels: ?



CF digestive disease

• Pancreatic disease– Exocrine pancreatic insufficiency– Diabetes– Pancreatic cysts (+ cancer)

• Gastro-intestinal disease– Reflux, gastroparesis– Meconium ileus, DIOS– Digestive infections– Digestive cancers


CF: Other systems involved

• Sinus disease

• Rheumatologic disease

• Osteoporosis

• Infertility

•…


Inhaled antibiotics: the evidence

• Meta-analysis of 16 randomized, controlled trials• most studies show ↑↑↑↑ lung function or ↓↓↓↓ decline in active Rx groups • some report ↓↓↓↓ hospital admissions, ↓↓↓↓ Ps ae density

Mukhopadhyay Thorax 1996

Ryan Cochrane Database Syst Rev 2003

• 520 patients,TOBI vs placebo, 24 weeks, ↑↑↑↑ lung function (adolescents),↓↓↓↓ density of Ps ae, ↓↓↓↓ hospitalization Ramsey 1999

• 128 adolescents, TSI, intermittent, 2 yrs, ↑↑↑↑ weight + lung functionMoss 2002

• 400 young CF patients with mild lung disease, TOBI vs placebo, 56 weeks, ↓↓↓↓ hospitalization + antibiotic use Murphy 2004

ConsensusClinically effective, very inefficient method of ab delivering, produces

high lung concentrations and low serum levels of ab

Ramsey et al. N Engl J Med 1999;340:23.

Mean Change in FEV1 in Patients Receiving Inhaled TOBI or Placebo

N = 520

• SLIT Amikacin (liposomal amikacin)

• Colistineb

• Aztreonam lysinate

Other novel inhaled antibiotics

Inhaled antibiotics: Dry powder formulations

Tobi Tobramycin DPIProof of principle (deposition)Safety (?), Doses ???, Efficacy ???

Pathogenesis

Defective CF gene




Infection

Inflammation

Bronchiectasis


Gene therapy




AntibioticsAZM



Macrolide Therapy for CF: the beginning

• Erythromycin therapy in a 16-year-old

Japanese CF patient with CF resulted in

improved pulmonary function Nakanisi Nippon Kyobu Shikkan Gakkai Zasshi. 1995

• 7 CF patients treated with 500 mg clarithromycin for 6 weeks, idem

Ordonez AJRCCM 1999

CF and AZI : randomized, placebo-controlled trials

� 60 adult patients, FEV1 56.6 (±±±± 22.3) %, Azi 250 mg/d vs. placebo, 3

mos

� LF stable vs. - 3.62 % FEV1, ↓↓↓↓ iv AB (0.37 vs 1.13 /patient), ↑↑↑↑ QoL

Wolter et al. Thorax 2002; 57: 212.

� 41 children, FEV1 61 % (33 - 80), Azi 250 - 500 mg 3x/wk vs.placebo,

6 mos →→→→ 2 mois « wash-out » →→→→ 6 mos cross-over

� FEV1 + 5.4 %, ↓↓↓↓ oral AB

Equi et al. Lancet 2002; 360: 978.

� 185 patients > 6 yrs, Ps. aeruginosa infection > 1 yr, FEV1 > 30 % PV

� 87 patients: Azi 250 - 500 mg 3x/wk; 98 patients: placebo, > 5 mo

� ↑↑↑↑FEV1, ↓↓↓↓ iv AB, ↑↑↑↑ weight by 0.7 kg

Saiman et al. JAMA 2003; 290: 1749.

LTB4 receptor antagonists…

CF and anti-inflammatory agents


Ibuprofen• CFF Registry on clinical use of Ibu, ±±±± 8000 patients,significant ↓↓↓↓ in yearly FEV1 decline

Schluchter 2004

LTB4 receptor antagonist = BIIL 284 BS• Early termination of study

Statins• Simvastatin once daily, 28 days• Outcome measures: exhaled biomarkers, inflammatory• markers in nasal epithelial cells / induced sputum, • not yet published

Pathogenesis

Defective CF gene




Infection

Inflammation

Bronchiectasis


Gene therapy




Antibiotics


Lung transplantation


Pathology

Sinus disease

Exocrine pancreaticinsufficiency

CFRD

Gastro-intestinal disease

Liver disease

Joint / Bone disease

Fertility / Infertility

Novel therapeutic approaches

Aerosol devices

Microbial pancreatic enzymesFatty acid supplementation ?

Islet cell transplantation ?

Medical RxIndications for liver transplantation

Insert normal

gene

Stabilize class I

mutations mRNA

cystic fibrosis: from the gene to the disease · cystic fibrosis: milestones •1938 « cystic...

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