CLINICAL YEAR
IN REVIEW
Assoc Prof. Kittipong Maneechotesuwan
Division of Respiratory Disease and TB
Faculty of Medicine Siriraj Hospital
February 2010
A NEW LOOK AT PATHOGENESIS OF ASTHMA
EMTU: Epithelial-Mesenchymal Trophic Unit
Holgate ST. et al. Clinical Science 2010
Holgate ST. et al. Clinical Science 2010
Structural and functional defect in airway
epithelium response to inhaled environment
Enhanced signalling between epithelium
and underlying structural cells (EMTU)
Microenvironment: facilitate allergic sensitization
:support different types of inflammation
:predispose to exacerbation
:drive airway remodeling
Defective innate
immune response
Holgate ST. et al. Clinical Science 2010
Dougherty RH, Fahy JV: Clin Exp Allergy 2009
bias DC response
towards Th2 response
facilitate allergen
penetration
Holgate ST. et al. Clinical Science 2010
Infections
TSLP AND ASTHMA
Thymic stromal lymphopoietin: ILIL-7 family
Mast cell
Epithelial cells
TSLP
“Immature
The master
switch
of
myeloid
DC
allergic inflammation”
inflammation”
Mature myeloid DC
TARC
(CCL17
(CCL
17))
Liu YJ: J Exp Med 2006
Anti-TSLP
AntiAnti--TSLPR
Anti
Anti--Ox40L
Anti
CXCR4
CXCR
4
Th2 cell
IL
IL--5
Eosinophil
Ox
Ox40
40L
L
Ox
Ox40
40
IL
IL--4,
IL
IL--13
B lymphocyte
Holgate ST. et al. Clinical Science 2010
•
Fetal immune: Th2 immune phenotype
•
Transition and balanced pattern of Th1 phenotype
•
If does not occur, infants are at high risk for developing asthma
•
Cord blood from newborns of farm-exposed mothers: high
levels of Treg, reduced Th2 cytokine production, increased
TLR2, TLR4 and CD14
• Maternal signalling to fetal immune system
Holt PG. J Exp Med 2009
CHOLINERGIC CONTROL OF AIRWAYS
CNS
Nodose
ganglion
Laryngeal
oesophageal
afferents
Airway wall
C-fibre
receptors
Irritant
receptors
Airway
epithelium
Vagus nerve
Parasympathetic nerve
Aδ
δ-fibre
C-fibre
ACh
Parasympathetic ganglion
Muscarinic
Submucosal
receptors
ACh
gland
Submucosal
ACh
gland
•
Neuronal release of Ach is highly facilitated by
eosinophilic airway inflammation
•
Inflammatory mediators trigger afferent sensory nerve
fibers, facilitate neurotransmission in nerve ending and
in the ganglion,
•
Muscarinic M2 receptor dysfunction (eosinophil infiltration
around airway nerve and secrete M2 receptor antagonist MBP)
• Role of cholinergic system in AHR and airway remodeling
Dekkers BG. Proc Am Thorac Soc 2009
• M3 receptor stimulation by itself is not mitogenic to ASM
• M3 receptor stimulation in the presence of growth factors
augments the proliferative responses to PDGF and EGF
• Inhaled anti-cholinergics reduce ASM mass during
growth factors released from allergen-challenged guinea
pigs
Dekkers BG. Proc Am Thorac Soc 2009
Th
Th2
2 LYMPHOCYTES IN ASTHMA
Dendritic cell
MHCII
B7.2
Co-stimulation
CD28
CD28 Co-
T cell receptor
CD3
CD3
GATA--3
GATA
IL
IL--13
IL
IL--4
Th
Th2
2 lymphocyte
IL
IL--5
IgE
Mast cell
Eosinophil
THE EFFECT OF ICS ON GATAGATA-3 REGULATION
CD3
CD3
CD28
CD28
Th
Th2
2 cell
Corticosteroid
p38MAPK
38MAPK
GRGR
Cytoplasm
Corticosteroids ↓ GATAGATA
-3 -1-α
MKPMKP
ImportinImportin
(Th
(Th2
2 cytokine expression)
• Rapid onset
• Potent effect
MKP--1 gene
GR GR MKP
Nucleus • Prolonged effect
GATA3
GATA
3
Th
Th2
2 cytokine gene
Allergic
IL
IL--4, IL
IL--5, IL
IL--13 inflammation
Maneechotesuwan K et al: PLosMed 2009;6:e1000076
Indoleamine-2, 3Indoleaminedioxygenase
(IDO)
THE PROBLEM OF CORTICOSTEROID RESISTANCE
• Corticosteroids are the most effective therapy currently
available for the treatment of many inflammatory diseases
• Corticosteroid resistance (CR) is a major barrier to the therapy
of several severe inflammatory diseases
• Molecular mechanisms of CR now being elucidated
• Novel therapeutic approach: reversal of CR
MECHANISMS OF STEROID RESISTANCE
Glucocorticoid
IL
IL--2+IL
+IL--4
IL
IL--13
MIF
Microbial
superantigens
cytoplasm
p38
P
GR
Ub
nucleus
Barnes PJ, Adcock IM: Lancet 2009
ERK
JNK
P
NO
NO
NFNF-κB GR
GR
GR
GRβ
β
GR GR
GRE
Inflammatory
cytokines
APAP-1
iNOS
INFLAMMATORY GENE REGULATION
INFLAMMATION
INFLAMMATORY
PROTEINs
↓ INFLAMMATION
CORTICOSTEROIDS
(Ito K et al: Mol Cell Biol 2000)
2000)
e.g. GMGM-CSF, ILIL-8
Coactivators
e.g. CBP
HDAC2
HDAC
2
HAT
Transcription
factors
e.g. NFNF-κB
Pol2
Pol
2
Histone
acetylation
AcAc-
mRNA
Histone
deacetylation
Ac-
mRNA
Ac-
Core
histones
Repressed chromatin
CLOSED
Ac-
AcAcAc- Activated chromatin
OPEN
Repressed chromatin
CLOSED
MECHANISMS OF CORTICOSTEROID RESISTANCE
• ↓ GR nuclear translocation: GR phosphorylation
- reversed by p38 MAPK inhibitors, LABA (severe asthma)
- Jak3-STAT5
- JNK phosphorylation
• Loss of GR: GR ubiquitination, nitration (COPD)
• ↓ GR-DNA binding (severe asthma)
• ↓ HDAC2: reversed by theophylline, PI3K inhibitors
(severe asthma, COPD)
Barnes PJ, Adcock IM: Lancet 2009
CIGARETTE SMOKING AND ASTHMA
25%
25% of asthmatics are current smokers
20%
20% of asthmatics are ex
ex--smokers
Excluded from trials of asthma therapy
• More likely to have symptoms despite ICS
• Treated with higher doses of ICS
•
More likely to be admitted to hospital
• Associated with more severe asthma
• Associated with more rapid decline in FEV1
• Associated with increased mortality
SMOKING AND RESPONSE TO ORAL STEROIDS
Prednisolone 40mg
40mg daily x 2 weeks
Current smokers (14
(14))
FEV1
300
p<0.01
200
N.S.
100
N.S.
0
Chaudhuri R et al: AJRCCM 2003
∆ Asthma control score
Non--smokers (26
Non
(26))
ExEx-smokers ((10
10))
0
N.S.
-0.2
-0.4
-0.6
N.S.
-0.8
-1
p<0.001
Asthma control
↓ HDAC IN SMOKING ASTHMATICS
HAT activity (dpm)
*
6000
*
4000
2000
*
*
100
**
0
0
Normal (n=8)
HDAC activity (dpm)
Fibreoptic bronchial biopsies
200
HAT
HDAC
Smoker (n=8)
Asthmatic (n=8)
Smoking asthmatic (n=6)
STEROID RESISTANCE IN SMOKING ASTHMATICS
NON--SMOKING ASTHMA
NON
Inflammatory stimuli
SMOKING ASTHMA
Cigarette smoke
Corticosteroids
Oxidative stress
Peroxynitrite
GR
NFNF-κB
NFNF-κB
↑ HDAC
HDAC2
2
Histone
acetylation
↑ GM
GM--CSF
↑ IL
IL--8
↑ eotaxin
Steroid
response
↓ Histone acetylation
↓ HDAC
HDAC2
2
Steroid
resistance
Histone
acetylation
↑GM
GM
GM---CSF
GMCSF
↑IL
IL
IL8
IL--8
↑eotaxin
eotaxin
STEROID RESPONSIVENESS IN SEVERE ASTHMA
25
20
*
+ Dexa (10
(10-6M)
15
10
5
0
Normal Mild
PBMCs
HDAC (µM/10
10µg protein)
GM-CSF
CSF release (% LPS alone)
Steroid responsiveness
Severe
Asthma
HDAC activity
**
25
15
10
5
0
Normal
Hew M et al: AJRCCM 2006
Mild
Severe
Asthma
2.5
p=0.01
1.92±0.2
PC20 (mg/ml)
2.0
1.5
1.03±0.2
1.0
0.5
0
≤ 30 ng/mL
Sutherland ER et al. AJRCCM 2010
30 ng/mL
Serum 25 (OH) D
• Steroid response (MKP-1 expression) ∞ serum
vitamin D
• Reduced vitamin D resulted in increased
expression of TNF-α
Sutherland ER et al. AJRCCM 2010
Dex
+
Dex + Vit D3
IL-10 ↓
IL-10 ↑↑
Treg from SR asthma
Th2 cytokine
Xystrakis E et al. J Clin Invest 2006;116:146-155
INTERLEUKIN--13 IN ASTHMA
INTERLEUKIN
Soluble ILIL-13 receptors (shuIL
(shuIL--13R
13Rα2)
IL
IL--4 mutant (pitrakinra)
Anti--IL
Anti
IL--13 antibody (CAT
(CAT354
354))
IL
IL4
CD23
STAT--6 inhibitors
STAT
Soluble ILIL-4 receptors not very
effective
Mast cell
IgE
Macrophage
(low ILIL-4 in adults)
Fibrosis
IL
IL--13
B lymphocyte
Fibroblast
Mucus hypersecretion
Goblet cells
Eosinophil
Eotaxin
Steroid resistance
IL-4 mutant (Pintrakinra)
Inhaled vs subcutaneous effects of a dual IL-4/IL-13
antagonist in a monkey model of asthma
Inhibit airway hyperresponsiveness
Allergy 2010;
2010;65:
65:6969-77
Anti-IL-13 Antibody (CAT354)
A phase 1 study evaluating the pharmacokinetics, safety and
tolerability of repeat dosing with a human IL-13 antibody
(CAT-354) in subjects with asthma
CAT-354 can be safely administered in multiple doses to
patients with asthma.
BMC Pulmonary Medicine 2010,10:3
Zeki AA. et al., AJRCCM 2009
Zeki AA. et al., AJRCCM 2009
Zeki AA. et al., AJRCCM 2009
Zeki AA. et al., AJRCCM 2009
New clinical trials of statins in asthma
The Effect of Statins on Asthma Control of Patients with
Chronic Asthma
Atovastatin in a 22 wk RCT
Effect of Statins on Asthma Control in Smokers with Asthma
Atovastatin in a 8 wk RCT: PEF, sputum cell count, NO, PFT
Statin Treatment in Patients with Moderate to Severe Asthma
Atovastatin at high dose 4 wks: PC20, FEV1, sputum eosino
The Additive AntiAnti-Inflammatory Effect of Simvastatin in
Combination with Inhaled Corticosteroids in Asthma (Mahidol
University)
Simvastatin 10 mg + budesonide 200 mcg/d in 8 wk RCT:
Sputum Eo
Exacerbation-prone Phenotype
•
Defined as multiple exacerbation requiring ≥ 3 bursts of oral
corticosteroids/yr
•
Mild (5%), moderate (13%) and severe (54%)
•
Irreversible airflow limitation, chronic sinusitis, psychological
dysfunction
Dougherty RH, Fahy JV: Clin Exp Allergy 2009
Anti-IL-5 Therapy (Mepolizumab)
• Refractory asthma:
• sputum Eo >3% at least on occasion in the previous
2 yrs in spite of high dose ICS or oral steroid therapy
• At least 2 severe asthma exacerbations in the
preceding 12 months
Nair P et al: NEJM 2009
Haldar P et al: NEJM 2009
Nair P et al: NEJM 2009
Haldar P et al: NEJM 2009
Anti--IL
Anti
IL--5 Therapy (Mepolizumab)
• Inhibition of interleukin-5 reduces eosinophilic inflammation
• Not all asthma is eosinophilic
• Reduction in eosinophils was associated with a decreased
rate of exacerbations (2.0 vs 3.4 per patient, P=0.02).
• Persistent eosinophilic inflammation despite corticosteroid
treatment is more common in patients with adult-onset
asthma than childhood onset asthma
Nair P et al: NEJM 2009
Haldar P et al: NEJM 2009
Anti--IL
Anti
IL--5 Therapy (Mepolizumab)
• Selective removal of eosinophils had no effect on other
asthma outcomes (symptoms, FEV1 and asthma
control)
• Eosinophils are not the only (or perhaps even the
major) cell involved in disease pathogenesis, even in
patients with severe asthma.
Nair P et al: NEJM 2009
Haldar P et al: NEJM 2009
Thank you for your attention
Barrett NA, Austen KF: Clin Exp Allergy 2009
Barrett NA, Austen KF: Clin Exp Allergy 2009
Sutherland ER et al. AJRCCM 2010;116
Xystrakis E et al. J Clin Invest 2006;116:146-155