therapy of metabolic myopathies

THERAPY OF METABOLIC
MYOPATHIES
Dr Pascal LAFORÊT
Centre de référence de pathologie
neuromusculaire Paris Est
Groupe hospitalier Pitié-Salpêtrière
Sources of fuel for muscle during
exercise
Fuel and exercise duration
• ATP: < 3 sec.
• Phosphocreatine:
• < 1 mn
• Carbohydrates
• < 5 sec (anaerobic
glycogenolysis)
• ~ 90 min (aerobic
glycogenolysis)
• Lipids:
• Several hours
Sahlin K, 1986
Overview of muscle energy metabolism
glycogen
glucose
ADP + Pi
NADH
O2 HgbO
2
Electron
TCA
cycle
NAD
ADP
ATP
lactate
free fatty
acids (FA)
H2O
OAA
ATP
pyruvate
carnitine
Transport
Acetyl CoA
Hgb
carnitine
FA CoA
CPT II
FA (n-2)
CoA
VLCAD
B oxidation
3 oxy
FA CoA
enoyl
FA CoA
triglyceride
Figure provided by Pr Ronald G. Haller
3 hydroxy
FA CoA
LCHAD
Metabolic myopathies
Disorders of muscle carbohydrates metabolism
glycogen
glucose
ADP + Pi
NADH
O2 HgbO
2
Electron
TCA
cycle
Muscle
glycogenosis
NAD
ADP
ATP
lactate
free
acids (FA)
ATP
Acetyl
CoA enzyme deficiency
Debranching
Hgb
carnitine
FA CoA
FA (n-2)
CoA
VLCAD
CPT II
B oxidation
3 oxy
FA CoA
enoyl
FA CoA
3 hydroxy
FA CoA
triglyceride
PAS staining
H2O
OAA
pyruvate
Phosphoglucomutase
carnitine
fatty deficiency
Transport
PAS staining
Pr Ronald G. Haller
LCHAD
Disorders of lipid metabolism
Multiple acyl-CoA
glycogen
dehydrogenase
glucosedeficiency
VLCADADP
deficiency
+ Pi
NADH
O2 HgbO
2
Electron
TCA
cycle
NAD
ADP
ATP
lactate
TG
free fatty
acids (FA)
H2O
OAA
ATP
pyruvate
carnitine
Transport
Acetyl CoA
Hgb
carnitine
FA CoA
CPT II
VLCAD
Lipidosis and
triglyceride
FAO disorders
Pr Ronald G. Haller
FA (n-2)
CoA
B oxidation
3 oxy
FA CoA
enoyl
FA CoA
3 hydroxy
FA CoA
LCHAD
Mitochondrial myopathies
Respiratory chain
disorders
glycogen
ADP + Pi
NADH
O2 HgbO
Electron
2
glucose
TCA
cycle
Transport
TG
NAD
ADP
ATP
lactate
free fatty
acids (FA)
OAA
ATP
pyruvate
carnitine
Acetyl CoA
Hgb
carnitine
FA CoA
FA (n-2)
CoA
VLCAD
CPT II
B oxidation
3 oxy
FA CoA
enoyl
FA CoA
SDH
triglyceride
H2O
COX
Pr Ronald G. Haller
3 hydroxy
FA CoA
LCHAD
Metabolic Myopathies
• Inherited errors of muscle metabolism
• Main causes:
– Glycogenosis: McArdle disease (GSD V), Pompe disease (GSD II),
debranching enzyme deficiency (GSD III), glycolysis deficiencies
– Lipid metabolism disorders : CPTII deficiency, β-oxidation defects
(VLCAD, multiple acyl-CoA dehydrogenase or ETF, trifunctional
protein deficiencies), Neutral Lipid Storage diseases
– Respiratory chain disorders (mitochondrial disorders)
• Clinical features in adults:
– Exercise intolerance ± recurrent rhabdomyolysis episodes
– Progressive muscle weakness ± cardiomyopathy (HCM > DCM)
– Multisystemic manifestations (children > adults)
Classification of muscle glycogenosis
(Glycogen Storage Diseases)
• Muscle glycogenosis with exercise intolerance and
rhabdomyolysis episodes:
– Myophosphorylase deficiency = McArdle (GSD V), PFK deficiency =
Tarui (GSD VII), phosphorylase b kinase (GSD IX), PGK, PGAM (X),
LDH (XI), Aldolase A (XII), β-enolase (XIII), PGM (XIV)
• Glycogenosis with permanent muscle weakness:
– Pompe disease (GSD II), debrancher deficiency (GSD III), branching
enzyme deficiency (GSD IV)
• Glycogen depletion disorders:
– Glycogen Synthase (GSD 0) and Glycogenin-1 deficiencies
• Cardiac glycogenosis:
– Danon disease and PRKAG2 cardiac syndrome
• Glycogenoses on the waiting list…
Pompe
GSDII
Andersen
McArdle
Branching enzyme
Deficiency
(GSD IV)
GSDV
XIV
Tarui
PhosphoFructokinase
GSD VII
GSD IX,X, XI, XII, XIII
CoriForbes
Debrancher
deficiency
GSDIII
McArdle’s Disease
McArdle disease
(Myophosphorylase deficiency)
•
•
•
•
Most common muscle glycogenosis
Autosomal recessive inheritance
Childhood or juvenile onset
Exercise intolerance:
– Muscle pain and fatigue at exercise
– « second wind » phenomenon after ≈ 10 minutes
due to increased delivery of free fatty acids and
improved glucose utilization
• Myoglobinuria ± renal failure in ≈ 50% cases
• Progressive muscle atrophy and weakness in
late adulthood in ≈ 30 % of patients
In vivo metabolic studies
Non-ischemic
forearm exercise
test (« grip-test »)
31P
and 13 C
NMR
spectroscopy
(J.-Y. Hogrel)
Cycling test on
cycle-ergometer
Forearm exercise test
(handgrip)
1 min
MVC estimation
Exercise
catheterization
Post-exercise blood samplings
T-5
– Monitoring of lactate and ammonia
levels after short exercise
– Analysis of anaerobic glycogenolysis
– Assessment of maximal voluntary
contraction and drop in force during
short exercise
T0
T1
T2
T3
T4
T6
T10
7
Lactate (mmol.l-1)
T-10
6
5
4
3
2
1
0
0
2
4
6
Temps (min)
8
J-Y Hogrel et al., Neurology 2001
10
Forearm exercise test = Grip test
Venous lactate
Ammoniemia
300
6
Ammoniémie (µmol.l-1)
Lactate (mmol.l-1)
7
5
4
3
2
1
0
250
200
150
100
50
0
0
2
4
6
Temps (min)
8
10
0
2
4
6
Temps (min)
• Hypolactatemia from T1 to T4
• Hyperammoniemia in all patients with McArdle disease
• Detection of 7/7 patients (100%)
8
10
(N Engl J Med 1987; 317:75-80)
Diagnosis of McArdle disease
• Childhood or juvenile onset
• Exercise intolerance:
– Muscle pain and fatigue at
exercise
– « second wind » phenomenon
after ≈ 10 minutes due to
increased delivery of free fatty
acids and improved glucose
utilization
• Myoglobinuria ± renal failure in
≈ 50% cases
• High CK levels at rest
• Progressive muscle atrophy and
weakness in late adulthood in ≈
30 % of patients after age 40
grip-test: absence of
lactate increase after
exercise + high
ammonia levels
• Genetic analysis: 3 recurrent mutations in PYGM
gene (R49X in one allele in 2/3 of patients)
Myophosphorylase
staining
McArdle: current therapies
• All but one clinical trials included fewer than 12 cases
• No meaningful responses with:
– Vitamine B6, branched-chain amino acids, high-protein diet..
• Positive effects of :
– Low doses creatine administration 60mg/kg/day (Vorgerd et al.,
2000) but pain worsening with high doses
– Oral sucrose administration before exercise (Vissing and Haller,
NEJM 2003)
• Positive role of regular exercise training:
– Decrease in pain sensation when physical leisure activity is
increased (K. Ollivier et al., 2005)
– Haller et al. (1998)
Constant workload cycling test :
benefit of oral sucrose in McArdle disease
(Vissing and Haller, NEJM, 2003)
O = placebo
Oral glucose
treatment in
McArdle disease
BPM 160
BPM 120
Benefit of oral
sucrose in patients
with McArdle
disease
Constant work
Above hard
Easy
Vissing & Haller. N Engl J Med
2003; 349: 2503-2509.
= Energy supplement
GSD with fixed muscle weakness
• Pompe disease (GSD II)
– Lysosomal disorder
– Second most common glycogenosis after McArdle disease
• Debranching enzyme deficiency (GSD III)
– Exercise intolerance (fatigability > pain) without
rhabdomyolysis is also a frequent feature
• Branching enzyme deficiency (GSD IV)
– Very high phenotypic variability: liver disease, myopathy +
cardiomyopathy, CNS involvement (Adult Polyglucosan Body
Disease)
• Glycogenin-1 deficiency
– Myopathy + cardiomyopathy
• Glycogen synthase deficiency:
– Exercise intolerance (fatigability), mild muscle weakness
cardiomyopathy, epilepsy
Pompe
Andersen
McArdle
Enzyme
branchante
Cori-Forbes
Enzyme
débranchante
Tarui
Phosphofructokinase
IX,X,XIII
XI
Clinical spectrum of Pompe disease:
(also known as acid maltase or α-glucosidase
deficiency or GSD II)
- Pompe disease (classical infantile)
- onset before 5 months
- cardiomyopathy, hypotonia, liver enlargement
- death due to cardiorespiratory failure < 1 yr
- residual GAA activity < 1%
- Non-classical infantile Pompe disease
- age at onset < 1 yr, death in 1st decade
- GAA activity < 2%
- Childhood and juvenile form
- onset in teens
- myopathy ± cardiomyopathy
- GAA residual activity: 2 to 6%
- Adult onset form
- onset after age 20
- myopathy ± respiratory insufficiency
- GAA activity: 7-23 %
Classic infantile Pompe disease
•
•
•
Age at first symptoms: 1,6 months
Age at diagnosis: 5,3 months
Age of death: 6,3 months
(98% of death before age 18 months)
• Delay between diagnosis and death: 2
mths
(van den Hout et al., Pediatrics, 2003)
•
Diagnosis:
– High CK levels
– Acid α-glucosidase activity in blood (dried
bloodspots+++)
– Molecular analysis
– Muscle biopsy: vacuolar myopathy
Late-onset Pompe disease
(lysosomal glycogen storage disease)
• Limb-girdle weakness
occurring after age 30
mimicking muscle dystrophy
• Frequent respiratory
insufficiency (diaphragmatic
involvement)
• Inaugural respiratory failure
as first symptoms of the
disease in some patients
• High CK level
Rigid spine syndrome
Kostera-Pruszczyk et al., NMD 2006
Laforêt et al, NMD 2009
Diagnosis :
Muscle biopsy: inconstant
vacuolar myopathy with PAS
positive stain (70% of cases)
Measurement of enzymatic
activity in leukocytes, in
fibroblasts or in muscle
Diagnosis of Pompe disease
Muscle biopsy: inconstant vacuolar
myopathy with PAS positive stain
(70% of cases)
Measurement of α-glucosidase activity
in blood (dried blood spots), or
fibroblasts if unexplained limb-girdle
myopathy
Enzyme replacement therapy (ERT)
• 1960s: failure of first attempt of enzyme therapy (fungus
enzyme from Aspergillus Niger and human placenta)
• 1996: recombinant GAA from transgenic rabbit milk1 and CHO
cells
• 1999: phase I and II trials with transgenic rabbit milk and CHO
cells [alglucosidase alfa, Myozyme™])
• 2000-2001: publications of pilot trials (Van den Hout et al.,
Lancet 2000; Amalfitano et al.,Genet Med 2001)
• 2003: pivotal clinical trials with Myozyme™ initiated
• 2006: EMEA and FDA marketing approval for Myozyme™
• 2007: publication of phase III clinical trial in 18 children
< 6 months old (Kishnani et al., Neurology 2007)
CHO = chinese hamster ovary.
1. Bijvoet, et al. 2. Van Hove, et al.
3. Koeberl DD, et al. J Inher Metab Dis. 2007;30:159-64.
Myozyme therapy in infantile-onset
Pompe disease: Overall conclusions
• ERT improves the natural history of Pompe disease
–
–
–
–
Significantly prolongs survival in infantile-onset patients
Cardiac size decreased in almost all patients
Several patients (≈ 30 %) have achieved independent ambulation
Efficacy has been also demonstrated in an advanced stage
population
• Treatment responses
– Early onset of treatment may be the key to obtain a good clinical
response
– The response in skeletal muscle is variable and may relate to
• degree of pre-existing cellular damage – “point of no return”
• other factors: CRIM status, antiRhGAA antibodies, residual GAA
activity, dosing, genetic background, autophagy…
• No major safety concerns
ERT trials in adults with Pompe
disease
• Adult-onset Pompe disease international, double-blind,
RCT (LOTS)
– 90 patients; aged > 8 years old
– 18 months of treatment
– primary endpoints: distance walked in 6 minutes (6
MWT) and forced vital capacity (FVC)
IPPV = intermittent positive pressure ventilation;
LOTS = late-onset treatment study;
RCT = randomized controlled trial.
Clinical trial NCT00158600. Avalable from: www.clinicaltrials.gov
Koeberl DD, et al. J Inher Metab Dis. 2007;30:159-64.
6MWT Change From Baseline (meters):
increased walking distance
+ 25 meters
- 3 meters
LME* p-value = 0.0464
•with robust variance estimation
GEE p-value = 0.0326
ANCOVA p-value = 0.0347
Baseline Mean (SD)
% predicted (SD)
Myozyme 332.2m (126.7)
50.7% (18.7)
Placebo
317.9m (132.3)
48.7% (20.4)
Week 78 Mean (SD)
% predicted (SD)
Myozyme 357.8m (141.3)
56.6% (21.4)
Placebo
313.0 m (144.6)
49.1% (22.6)
FVC Change in Mean % Predicted
Myozyme® stabilises pulmonary
function, whereas untreated patients
continue to decline
4
3
2
+1.2%
1
0
Myozyme
Placebo
-1
-2
-3
-2.2%
-4
-5
0
20
40
60
80
Weeks from Baseline
Baseline Mean (SD)
Week 78 Mean (SD)
Myozyme 55.4% (14.4)
Myozyme 56.7% (16.4)
Placebo
53.0% (15.7)
Placebo
51.1% (15.8)
100
LME with robust variance
estimation p-value = 0.0041
ANCOVA p-value = 0.0055
J Neurol.2009
• 44 adults:
– 7 wheelchairbound, 6MWT performed in 22 patients
– Mean CV = 69,6% (33 patients), NIV in 16 cases
• 6MWT: 341 m at T0, 393
m after 1 year
• + Exercise on ergocycle in
5 patients
• Stabilisation of MMT and
VC
• 24 patients: 7 juvenile forms, 17 adults
– 6MWT performed in 14 patients
– NIV: 13 cas
• Improvement of
6MWT with plateau in
adults
• VC stable
• reduction of NIV
duration from 14 to 8h
Treating Pompe disease:
conclusion (1)
• Major beneficial effects of alglucosidase alfa on survival in
children with variable improvement of cardiac, motor and
respiratory functions
• Longest survivors of first trials are now 10 years old
• Improvement in walking distance and stabilization of
pulmonary function in ambulatory adults
• Myozyme® might also improve QoL and respiratory function
in severe late-onset Pompe disease patients
• Shall we observe a clinically meaningful improvement after
several years of treatment or only a stabilization of the
disease ?
Alglucosidase alfa (Myozyme)
500 euros/vial of 50 mg
200 000 to 500 000 euros/year for one adult
Treating Pompe disease:
conclusion (2)
• There is a need for determining clinical and biological
prognostic factors:
– CRIM status in children +++
– GlC4 in urines as a biomarker of response to treatment ?
– Muscle MRI to assess the severity of muscle destruction
• These results strengthen the importance of continuing a
long-term and standardized follow-up of all patients, and to
collect prospective data through country-based or
international registries
• Need to establish guidelines on criteria allowing to
determine whether to treat or not to treat, and when to stop
treatment
Disorders of muscle lipid
metabolism
• Fatty acid oxidation disorders:
• Carnitine Palmitoyl Transferase 2 (CPT 2) deficiency
• Very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency
• Multiple acyl-CoA dehydrogenase (MAD) deficiency (ETF and ETFDH deficiencies)
• Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD)/
Mitochondrial Trifunctional Protein (MTP) deficiencies
• Primary Carnitine deficiency (PCD)
• Neutral lipid storage diseases:
• Adipose triglyceride lipase (ATGL) and CGI-58 (Chanarin-Dorfman)
deficiencies
• Phosphatidic acid phosphatase (Lipin-1) deficiency
carnitine
Disorders of muscle lipid
metabolism: clinical features
• Most often pediatric diseases:
– Recurrent hypoketotic hypoglycemia,
encephalopathy, liver failure, cardiomyopathy,
rhabdomyolysis, sudden death…
• Predominant muscular symptoms in adults;
– Exercise intolerance ± rhabdomyolysis attacks in FAO
disorders and LIPIN1 gene mutations
– Permanent muscle weakness in carnitine deficiency,
NLSD, and MADD (+ cardiomyopathy in PCD/NLSD)
• Clinical manifestations triggered by fasting, fever
and stress in FAO disorders
Fatty acid oxidation disorders
• Childhood or juvenile onset
• Inconstant exercise intolerance…
• But myalgias and rhabdomyolysis
episodes after intense exercise
• Other triggering factors:
– Fever, cold, fasting, stress…
• CK and lactate levels often
normal at rest
• grip-test and cycling test most
often normal
• The key for diagnosis is the
acylcarnitines profile analysis
– To perform during acute crisis, or
after 12h fast
– May orientates the molecular
studies towards specific enzyme
deficiency: CPTII, VLCAD, ETF,
TFP…
Muscle biopsy often non conclusive,
or may show a mild lipidosis
3 WEYLAND Leda
190203WEY 1 (3.001) Sm (SG, 2x1.00); Sb (1,40.00 )
305
100
Parents of 99ES+
6.20e5
384
445
414
221
%
440
386
218
307
267
382
412
438
232
• Search for LPIN1 mutations if
FAO disorder excluded
290
260
200
0
200
220
240
260
276
280
358
330
299
300
320
370
341
340
360
401
380
400
427
420
458 461
440
460
480
m/z
500
CPT2 and VLCAD deficiency
• Rhabdomyolysis episodes induced by
exercise, fever, cold, and fasting
• Absence of permanent muscle weakness
• Rarely cardiomyopathy (VLCAD)
• Absence or mild lipidosis on muscle
biopsy
• Typical acylcarnitine profile in VLCAD
deficiency (C14:1 peak)
Multiple acyl-CoA dehydrogenase
(MAD) deficiency
•
•
•
•
•
Rhabdomyolysis + abdominal pain, vomiting, and liver
enzymes
increase
±
encephalopathy
Unlike other FAO disorders, permanent muscle
weakness is frequent in MADD
Muscle lipidosis on muscle biopsy, mitochondrial
abnomalies, and coenzyme Q deficiency
Combined elevation of all chain length acylcarnitines
(C4 to C18:1) in all patients
ETFDH gene mutations are the major cause of adult
MADD
Dramatic response to CoQ10 and riboflavin treatment
in some patients
MADD: patient with muscle lipidosis
MADD: patient with mitochondrail abnomalies
Muscle lipid disorders: diagnosis
• Plasma acylcarnitine profile is the best diagnostic tool for
FAO disorders
C14:1
VLCAD deficiency
C0
C2
C16
*
* ** *
*
C12
*
*C18:1
• + CPTII activity assessment in blood sample
• Genetic analysis orientated by results of acylcarnitine
profile: CPT II, ACADVL, ETFDH , HADHA, HADHB
• search for LPIN1 mutation if normal acylcarnitine profile
and normal CPT II activity (P DeLonlay)
• 59 % of children (17/29) with rhabdomyolysis (CPK > 10
000) of onset before 5 years of age, after exclusion of
FAO defect
• Mean age of rhabdomyolysis = 21 months
• 5 deaths (1 to 6 years)
• Triggering factors: fever, fasting, anesthesia
• Acylcarnitines profile always normal
• Muscle biopsy: mild an inconstant lipidosis
• Intragenic deletion in 47 % of patients
Blunted fat
oxidation
during exercise Palmitate oxidation
in VLCAD
deficiency
Total fat
oxidation
Orngreen MC, Nørgaard
MG, Sacchetti M, van
Engelen BG, Vissing J.
Fuel utilization in
patients with very longchain acyl-CoA
dehydrogenase
deficiency. Ann Neurol
2004; 56: 279-282.
VLCAD patients; black symbols
Healthy subjects; open symbols
The rationale for treating defects of
β-oxidation defects with fibrates
• Fibrates are ligands of Peroxisome-proliferator
activated receptor alpha (PPARα)
• PPARα is a transcription factor that can induce
expression of genes involved in β-oxidation of fats
• It is a prerequisite for treatment effect that the gene
expresses a protein with some preserved functionality.
Bezafibrate: effects on CPTII activity
Bonnefont JP et al. NEJM 2009;360(8):838-840
Bezafibrate: effects on CPTII activity
But, lack of objective
measure of skeletal
muscle symptoms
improvement
Bonnefont JP et al. NEJM 2009;360(8):838-840
The French – Danish collaboration
Centre de Référence de
pathologie
neuromusculaire ParisEst and Dept
d’Explorations
Fonctionnelles
Respiratoires,
GHPS
Collaboration
Neuromuscular
Research Unit,
Rigshospitalet,
Copenhagen
Aim of the study
Investigate the effect of Bezafibrate on skeletal muscle metabolism
during exercise in 10 patients with CPTII and VLCAD deficiencies
Design:
Double blind, placebo-controlled, crossover.
Primary outcome measures:
1) Fatty acid oxidation rates measured by stable isotope technique
2) Heart rate response to exercise
Experimental setup
Effects of bezafibrate on fat metabolism
Perceived exertion and heart rate
Conclusion
Bezafibrate does not improve fatty oxidation or
exercise tolerance during exercise in patients
with CPTII and VLCAD deficiencies
Bezafibrate decreases fatty acid availability,
which impairs fat oxidation in vivo
Thus, in vitro studies suggesting a therapeutic
potential for fibrates, do not translate into
clinically meaningful effects in vivo
Neuromuscular Research Unit, Department of Neurology, Rigshospitalet, University of Copenhagen,
Denmark