Asthma and Cystic Fibrosis
Christopher Hug, MD, PhD
Division of Respiratory Diseases
Children’s Hospital Boston
Whitehead Institute
What is Asthma?
What is Cystic Fibrosis?
What can these conditions tell us about
lung biology and disease?
Case 1:
5 year old boy, born in Boston.
Coughs and wheezes frequently.
Several viral illnesses per year. First, and most severe episode,
occurred when he was 7 months old.
Good growth and development.
Has patches of dry skin on elbows and cheeks.
Mother, father, and sister with similar symptoms.
Father smokes, but “only outside.”
Lives near Dudley MBTA station.
Case 2:
11 year old boy, born in Boston.
Coughs and wheezes frequently, with bronchitis and pneumonias.
Difficulty gaining weight; frequent constipation
and abdominal pain.
Nasal polyps noted.
Other family members healthy. Visits relatives in Ireland and
Scotland yearly.
No smokers or environmental exposures.
Case 3:
19 year old woman, born in Boston.
Coughs only occasionally, wheezes with exercise.
Generally healthy, moderately overweight.
Frequent loose stools.
Mother morbidly obese; father healthy.
Noted to have “lung scarring” on chest X-ray, taken by
Immigration Service when visiting family in Montreal.
Asthma:
intermittent obstruction to air flow induced by
a variety of stimuli in a susceptible individual.
Genetic: strong family history
Immunologic: inflammation
Environmental: irritants and allergens
Infectious: viral infections and inflammation
Mechanical: obstruction to airflow
Airway Inflammation in Childhood Asthma
Asthma
Control
Thickening of basement membrane, leads to proliferation of smooth
muscle and reduced airway lumen.
Barbato, AJRCCM, 2003
What causes a reduction in airway lumen?
-inflammation
infection, usually viral
irritation, such as gastric acid
allergic, autoimmune
systemic illness or disease
What causes a reduction in airway lumen?
-inflammation
infection, usually viral
irritation, such as gastric acid
allergic, autoimmune
systemic illness or disease
Chronic airway inflammation and constriction
may become irreversible with time, as
the lung responds to inflammation with
proliferation of smooth muscle around
the airway.
Why is constriction of the airways a bad thing?
Resistance to laminar flow within the connecting airways
is dependent on several properties of the lung
(Poiseuille’s law)
R =
n viscosity
l length
r radius
8 nl
!r4
Why is constriction of the airways a bad thing?
Resistance to laminar flow within the connecting airways
is dependent on several properties of the lung
(Poiseuille’s law)
R =
8 nl
!r4
n viscosity
l length
r radius
If the radius is halved, the resistance increases 16-fold!
How is asthma diagnosed?
-history: wheezes with colds
-physical exam: wheeze, cough, signs of allergy
-laboratory evaluation:
Chest X-ray
Pulmonary Function Tests (PFT)
Peak Expiratory Flow Rate (PEFR)
lab tests:
immune function
allergic component
sweat test (CF)
Asthma Severity Scoring
•
•
•
•
Mild Intermittent
Mild Persistent
Moderate Persistent
Severe Persistent
Control of Factors Contributing to
Asthma Severity
•
•
•
•
Allergens
Environmental triggers
Exercise
Can asthma be prevented?
Pharmacologic Therapy
• Goals of therapy
• Step-wise approach to asthma
management
• Follow-up recommendations
Effects of Inhaled
Corticosteroids on Inflammation
E = Epithelium
BM = Basement
Membrane
Pre– and post–3-month treatment with budesonide (BUD) 600 mcg
b.i.d.
Laitinen et al. J Allergy Clin Immunol. 1992;90:32-42.
Effects of Corticosteroids on Inflammatory Cells
adhesion molecules
CPLA 2 IL-8
GRO-β
GROβ
IL-16
NO
FGF
MCP-1
CGRP
GM-CSF
IGF-I
MCP-2
PGE2
RANTES
PGF2α
IL-1β
IL-1
β
15-LT5
TNF-α
TNFα
iNOS
IL-6
COX 2
dendritic
cell
IL-12
IL-1
ICAM-1/3
CD8
CD4
ET-1
SLPI
15-LD
antigen presentation
VIP
IL-3
9/13 HODE
IL-5
15-HETE
IL-10
eotaxin
MIP-1α
MIP-1
α
ICAM-1PDGF IL-17
IL-8
histamine
cytokines
IL-4
IL-13
LTD-4
IL-1β
IL-1β
LTC-4
LTD-4
LTE-4
PGS
GM-CSF
IL-6 IL-8
IgE
2
PGS
BIP
O species
neutrophil
IFN-γ
IFN-γ
TXA 2
IL-5
PAF
PGE2
IL-8
iNOS
IL-β
IL-β
IL-1β
IL-1β
cytokines
NO IL-6
eotaxin
protease
G-CSF
L-selectin
TNF-α
TNF-α
IL-1
IL-4
MBP
adhesion molecules
PGE2
IL-14
cytokines
RANTES
MCP-2
MCP-3
IL-8
GM-CSF
LTC-4
TNF-α
TNFα
eotaxin
SCF
IFN-γγ
IFN-
TNF-α
TNFα
PAF
IL-13
GM-CSF
smooth
muscle cell
GM-CSF
TGF
ICAM-1
PAF
IL-4
HB-EGF
TXB-2
0 species
PDGF-B
IL-4
MCP-2 IL-2 15-HETE
neurone
IgE
B cell
GM-CSF
IgE
IL-13
IL-3
IL-1α
IL-1α
IL-5
TNF-α
TNF-α
Th-2
IL-6
IFN-γ
IFN-γ
SCF
IL-3
chemokines
IL-6
LTB-4
eotaxin
histamine
PGD2
Mediator release
neurokinins
modified
Th-0
IL-2
IL-4
LTD-4
IL-8
Th-1
IFN-γ
IFN-γ
MIP-1α
MIP-1
α
IL-10
LTE-4
RANTES
COLLAGEN I, II,
V
IL-13
IL-1
3
IL-8
IL-4
mast
cell
MCP-1
MIP-1
IL-1α
IL-1
α
LTC-4
MCP-1
IL-8
IL-6
IL-2
LTD-4
IL-6
MIP-1α
MIP-1
α
MCP-3
TGF-β
TGF-β
PGE 2
TNF-β
TNF-β
EDP
IL-10
RANTES
GM-CSF
IL-1
MCP-3
GM-CSF
tryptase IL-5 IL-1
VCAM-1
IFN-γ
IFN-γ
EDN
IL-5
ICAM-1
NCF
IL-3 O2 CR-3
GM-CSF
MCP-1
IL-6
SCF
PDGF
RANTES
0 species
IL-10 IL-12
eosinophil
RANTES
IFN-γγ
IFNECP
IL-11
GM-CSF
IL-3
LTB-4
ET-1
basophil
TNF-α
TNF-α
IL-4
ET-2
PAF
IL-2
MCP-3
endothelial cell
TXA
MPO
LTC-4
IL-5
PAF
IL-6
ICAM-1
collagenase
ICAM-1
eotaxin
IL-1
RANTES
IL-10 IL-8 PGE2
TGF-β
TGF-β1
G-CSF
MIP-1α
MIP-1α
MCP-3
TNF-α
LTB-4 TNF-α
LTC-4
LTB-4
IFN-γγ TNF-α
0 species IFN- TNF-α
IL-12
GM-CSF
EAF
IL-1β
IL-1β
IL-6
MIP-1α
MIP-1α
epithelial cell
protease
macrophage
IL-3
IL-11
NEP
fibroblast
monocyte
myofibroblast
GM-CSF
C-kit
IL-6
Effects of Leukotriene Modifiers on
Inflammatory Cells
adhesion molecules
CPLA 2 IL-8
GRO-β
GROβ
IL-16
NO
FGF
MCP-1
CGRP
GM-CSF
IGF-I
MCP-2
PGE2
RANTES
PGF2α
IL-1β
IL-1
β
15-LT5
TNF-α
TNFα
iNOS
IL-6
COX 2
IL-11
NEP
IL-12
15-LD
0 species
GM-CSF
ICAM-1/3
IL-3
IL-5
15-HETE
IL-10
eotaxin
MIP-1α
MIP-1
α
ICAM-1PDGF IL-17
GM-CSF
IL-6
IL-8
IgE
LTC-4
IL-1
tryptase IL-5 IL-1
IL-4
GM-CSF
eotaxin
IL-8
IL-6
MIP-1
RANTES IL-3 O2 CR-3
EDN
IFN-γγ
IFNEDP
ECP
GM-CSF
MCP-1
TNF-β
TNF-β
IL-1α
IL-1
α
IL-13
IL-8
LTE-4
TNF-α
TNFα
TNF-α
TNFα
IL-13
GM-CSF
GM-CSF
TGF
ICAM-1
PAF
IL-4
HB-EGF
neurone
IgE
GM-CSF
IgE
IL-13
IL-3
IL-1α
IL-1
α
IL-5
TNF-α
TNFα
Th-2
IL-6
B cell
Th-0
IL-2
IL-4
SCF
IFN-γγ
IFN-
IFN-γ
IFN-γ
MIP-1α
MIP-1
α
IL-4
IL-8
IL-2
LTD-4
IL-5
IL-10
LTD-4
IFN-γγ
IFN-
SCF
IL-3
chemokines
IL-6
LTB-4
eotaxin
histamine
PGD2
Mediator release
modified
Th-1
IFN-γ
IFN-γ
MBP
LTC-4
mast
cell
RANTES
COLLAGEN I, II, V
eosinophil
TXB-2
0 species
PDGF-B
IL-4
MCP-2 IL-2 15-HETE
MIP-1α
MIP-1
α
MCP-1
0 species
NO IL-6 IL-10 IL-12
IL-6
adhesion molecules
PAF
smooth
muscle cell
TGF-β
TGFβ
PGE2
GM-CSF
IL-10
RANTES
IL-14
IL-8
cytokines
VCAM-1
GM-CSF
RANTES
LTC-4
GM-CSF
cytokines
IL-8
MCP-3
ICAM-1
RANTES
MCP-3
L-selectin
TNF-α
TNFα
ET-1
MCP-3
MCP-2
IL-6
ET-2
PAF
NCF
PGE2
G-CSF
PGS
BIP
O species
neutrophil
basophil
MCP-1
PGE2
eotaxin
protease
endothelial cell
TXA 2
LTE-4
PGS
IL-4
IL-1β
IL-1
β
LTB-4
SCF
IL-1
PAF
MPO
LTD-4
IL-13
IL-β
ILβ
TGF-β
TGFβ1
IL-1β
IL-1
β
LTC-4
TXA 2
MCP-3
IL-10 IL-8 PGE2
LTD-4
IL-4
TNF-α
TNFα
MIP-1α
MIP-1
α
IL-3
iNOS
RANTES
IL-6
cytokines
PAF
MCP-3
TNF-α
α
LTB-4 TNFIL-8
histamine
IL-1
MIP-1α
MIP-1
α
epithelial cell
protease
IL-6
IL-11
PDGF
IL-2
IFN-γγ
IFN-
EAF
IL-5
antigen presentation
VIP
9/13 HODE
ICAM-1
collagenase
ICAM-1
eotaxin
IL-5
IL-3
CD4
G-CSF
LTB-4
IFN-γγ TNFIFNTNF-α
α
IL-12
IL-1β
IL-1
β
CD8
ET-1
SLPI
LTC-4
IL-1
fibroblast
monocyte
macrophage
dendritic
cell
neurokinins
myofibroblast
GM-CSF
C-kit
IL-6
Do children outgrow asthma?
MARTINEZ, JACI, 1999
Description of Cystic Fibrosis
“Cystic Fibrosis of the Pancreas and its
Relation to Celiac Disease: A Clinical and
Pathologic Study”
Dorothy H. Anderson, M.D.
Am J Dis Child 1938;56:344-99
“The chief pathologic changes were as
follows:
1. The acinar tissue of the pancreas was
replaced by epithelium-lined cysts
containing concretions…
2. The lungs showed bronchitis,
bronchiectasis, pulmonary abscesses
arising in the bronchi…”
Cystic Fibrosis
ν
ν
ν
ν
ν
Most common lethal inherited disease in Caucasians
(25,000 in US)
Incidence: 1:2500 births (4% carriers)
Clinical manifestations: progressive bronchiectasis, chronic
cough and sputum production, dyspnea, respiratory failure
Standard therapy: chest physical therapy, inhaled
mucolytics, antibiotics, and oral pancreatic enzyme
replacement
Median survival (years):
35
ν
ν
ν
Enzyme supplements
Improved antibiotics
General care and nutrition
30
25
20
15
10
5
0
1940
1950
1960
1970
1980
1990
2000
Organs affected by CF
ν
ν
ν
ν
ν
ν
Airways
Liver
Pancreas
Small intestine
Reproductive tract
Skin (sweat gland)
CFTR: Cystic Fibrosis Transmembrane Regulator
Gene cloned in 1989 by studying large families with CF
Located on chromosome 7, spanning 188,700 bp; 27 exons
Many mutations now identified:
over 800 individual mutations that cause CF
“Hot-spot” for mutation - possible role in pathogenesis?
Most common in Northern Europe:
delta-F 508 homozygous, caused by a triplet nucleotide
deletion
Localization of CFTR expression
Epithelial (high)
Pancreatic ducts
Salivary/sweat ducts
Male genital ducts
Kidney tubules
Epithelial (low)
Lung
Jejunum/colon
Potential other
Fibroblasts, organelles
Respiratory epithelium
(Exocrine tissues)
Infection and inflammation lead
to airway obstruction
Correlates of pulmonary disease
progression: Bronchiectasis
Pathogenesis of CF lung disease
Predicted structure of CFTR
(Cystic Fibrosis Transmembrane conductance
Regulator)
CF pathophysiology: role of
CFTR
CF: a heterozygote advantage?
ν
ν
ν
Clinical picture of CF reported world-wide
Highest gene frequency found in Northern Europe
(approximately 1 in 25)
Persistence of a “lethal” gene:
ν
ν
ν
ν
genetic drift
recurrent random mutations
heterozygote advantage (increased fertility or survival benefit)
Selective advantage of 2% occurring 23 generations ago
could explain high observed incidence of CF
Principal infectious causes of
infant mortality
(ca 500-1500 AD)
ν
ν
ν
ν
ν
Plague
Smallpox
Typhus
Endemic tuberculosis
Epidemic cholera
Rodman and Zamudio, Med Hypoth 1991; 36:253
CF: a heterozygote advantage
Fluid accumulation ratio
Fluid accumulation in mouse small intestine
in response to infusion of cholera toxin
2
1.5
1
0.5
0
-/-
wt/CFTR genotype
Gabriel et al, Science 1994, 266:107
wt/wt
Effectors of CFTR Phenotype
CFTR genotype
Basic defect
Modifier genes
Symptoms
Environmental
factors
CFTR Mutations in Other Diseases
ν
Congenital bilateral absence of vas deferens (CBAVD)
ν
Obstructive azoospermia
ν
Chronic obstructive pulmonary disease (COPD)
ν
Diffuse bronchiectasis
ν
Allergic broncopulmonary aspergillosis
ν
Chronic pseudomonas bronchitis
ν
Chronic bronchial hypersecretion
ν
Chronic sinusitis
ν
Pancreatitis
ν
Asthma
Genotype-Phenotype Correlations
Sweat gland:
GOOD
Genotype
Pancreas: GOOD
Lung: BAD
Adapted from Welsh and Smith. Sci Am. 1995;273:52-59.
CFTR Mutation and
Clinical Consequence
Normal
CBAVD,
COPD,
pancreatitis,
etc.
PS
CF
PI
Severity scale
Typical mutations
Atypical mutations
CF lung disease
Molecular Consequences of CFTR
Mutations
Normal
I
No
synthesis
Nonsense
G542X
Frameshift
394delTT
Splice junction
1717-1G–>A
II
III
IV
V
Block in
Reduced
Block in
Altered
processing regulation conductance synthesis
Missense
AA deletion
ΔF508
Missense
G551D
Missense
R117H
Missense
A455E
Alternative
Splicing
3849+10kbC–>T
New therapies for CF
Abnormal Gene
Abnormal Protein
Genetic therapy
Molecular therapy
- tgAAVCF
- Liposomes
- Receptor-mediated
Gene transfer
- Gentamicin
- Phenylbutyrate
- Genestein
- 7,8 Benzoflavones
- CPX
- Curcumin
Altered Ion Transport
Abnormal Mucus
Secretion
Infection &
Inflammation
Tissue Destruction
Ion Transport
Infection
- INS37217
- Moli1901
(Duramycin
(Duramycin))
- TOBI efficacy study
- TOBI nebulizer study
- P113D
- IB367
- RSV vaccines
- PA1806
- Macrolides
Mucolytic
- Nacystelyn
Inflammation
Organ Destruction
Respiratory
Failure
Destruction
Organ
Transplantation
Gene replacement therapy
ν
ν
Rationale: abnormal gene leads to production of
abnormal CFTR
Available therapies:
ν
ν
none
Potential therapies:
ν
ν
viral vectors
non-viral methods
CFTR molecular therapy
ν
ν
ν
Rationale: abnormalities in CFTR lead to defective processing,
regulation, or conduction
Available therapies:
ν none
Potential therapies:
ν replace missing CFTR protein
ν “chaperone” CFTR to apical membrane (i.e. ΔF508)
ν activate defective CFTR
ν suppress stop-codon mutations with antibiotics, such
as gentamicin
Airway secretions and clearance
Pulmozyme® (rhDNase)
improves CF sputum pourability
Shak S, et al Proc Natl Acad Sci USA 1990;87:9188-92
N-acetyl L-cysteine (Mucomyst)
ν
Mucolytic
ν
Anti-inflammatory
ν
Antiprotease
ν
Antioxidant
TOBI: inhaled tobramycin
antibiotic
ν
ν
ν
ν
Specific and potent antibiotic against
pseudomonas bacteria
Inhaled delivery system reduces systemic toxicity
Usually combined with other antibiotics
Can be delivered at home, reducing exposure
to other bacteria
Airway inflammation in CF:
Neutrophil dominated
Anti-inflammatory therapy: Effect
of ibuprofen on FEV1
Konstan MW, et al New Eng J Med 1995;332:848-854
Lung Transplantation
ν
ν
ν
ν
ν
ν
Final therapeutic option
Technical and surgical hurdles manageable
Decision when to transplant remains difficult
5-year survival is approximately 50%
Limited availability of organ donation
Challenge is in long term treatment of immunosuppression and rejection
Therapeutic Approaches to CF
Abnormal Gene
Genetic therapy
- tgAAVCF*
tgAAVCF*
- Liposomes
- Receptor-mediated
Gene transfer
Abnormal Protein
Altered Ion Transport
Abnormal Mucus
Secretion
Infection &
Inflammation
Tissue Destruction
Molecular therapy
Ion Transport
Infection
- Gentamicin
- Phenylbutyrate
- Genestein
- 7,8 Benzoflavones
- CPX
- INS37217*
- Moli1901
(Duramycin
(Duramycin))
- TOBI efficacy study*
- TOBI nebulizer study
- P113D
- IB367
- RSV vaccines
- PA1806
- Macrolides
- Curcumin*
Curcumin*
Mucolytic
- Nacystelyn*
Nacystelyn*
Inflammation
- DHA (Lumarel
(Lumarel))
- Protease inhibitors
- BIIL 284*
- Tyloxapol
- GSH, Immunocal
- Interferon gamma
Organ Destruction
Respiratory
Failure
Transplantation
Acute and
chronic rejection
Long term
immmunosupression
Future Studies and Treatments
ν
ν
ν
ν
ν
ν
ν
Improved nutrition, antibiotics, and support
Role of early diagnosis through newborn
screen
Gene therapy
Stem cell therapy
Improved transplantation treatments
Modifying genes
Understanding of cellular role of CFTR
protein
What do Asthma and CF have in
common?
ν
ν
ν
ν
ν
ν
Genetic basis
Broad spectrum of clinical presentation
Expression of symptoms related to other
factors
Airway inflammation
Similar treatments: anti-inflammatory
medications
Modifying genes
How do Asthma and CF differ?
ν
ν
ν
ν
ν
ν
ν
Genetic basis: single gene versus many
Tissue and organs affected
Airway inflammation
Different treatments: antibiotics and nutrition
Different progression of disease
Modifying genes
However, basic science advances may shed light on
both diseases
Acknowledgements
Much of the material contained on the slides was provided by
the Cystic Fibrosis Foundation
Dr. Harvey F. Lodish
Whitehead Insitute
Drs. David Waltz and Greg Sawicki
Children’s Hospital Boston
Special thanks to the patients for participating in clinical trials
BALF neutrophil counts in CF
Birrer P, et al. Am J Resp Crit Care Med 1994;150:207-213
Molecular therapies for CF
Therapeutic approaches to CF
lung disease
Introduction to Cystic
Fibrosis
Christopher Hug, MD, PhD
Pulmonary Division
Department of Medicine
Children’s Hospital, Boston