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Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor, Departments of Pediatrics and Clinical Neurosciences, University of Calgary, Canada.

Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

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Page 1: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Rodent models of infantile spasms and the hunt for new

treatments

Morris H. Scantlebury M.D. Assistant Professor, Departments of

Pediatrics and Clinical Neurosciences, University of Calgary, Canada.

Page 2: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Treatments

• Vigabatrin- effective 20-30% of the time. Much higher in patients with TS.

• ACTH/prednisolone- Effective 60-70% of the time

• Treatments are refractory 30-50% of the time

Both treatments associated

with considerable toxic

side-effects!

Page 3: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

• Persistent psychomotor disabilities despite treatment

• Emergence of other seizure types

• High mortality of ~ 30% (50% are disease-related )

Outcome Infantile Spasms

Page 4: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

• WE NEED SAFER AND BETTER TREATMENTS FOR INFANTILE SPASMS

Page 5: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

ANIMAL MODELS OF INFANTILE SPASMS

Page 6: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Animal models of epilepsy: What are the considerations to model?

• There are many, many experimental models of epilepsy involving both in-vivo and in-vitro preparations

• There are several things to consider when evaluating or developing a model of epilepsy– Species – Syndrome– Developmental specificity– Sex differences– Etiology– Methods of induction– Anatomical targets (Where to direct the inciting insult, where should be the

damage– Genetic background– Predisposing factors– Reason for using the model (high throughput for screening drugs or to study

mechanisms)– Comorbidities (depression, autism, learning and memory deficits)– COST!!!!!!!

Page 7: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

SPECIES DIFFERENCES

DeFelipe J, Frontier in neuroanatomy 2011

Page 8: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

HUMAN MOUSE

DeFelipe J, Frontier in neuroanatomy 2011

Page 9: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

DeFelipe J, Frontier in Neuroanatomy 2011

Page 10: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Which epilepsy syndrome to model?

Blumke et al, Epilepsia 2011

*

*

*

*

**

*

*****

*

*

*

Page 11: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Lee et al, Epilepsia 2008

Chronic TTX Infusion (right hippocampus)Model of Infantile SpasmsModel of sodium channel dysfunction

Page 12: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

HFO increase at time of seizure

Page 13: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Vigabatrin suppresses spasms and late HFO of ictal onset

Interictal HFOs were also suppressed

Page 14: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

• ECOG, 636 spasms in 11patients

• 104-148 contacts

– Placement guided by EEG, MRI, PET

• Recorded HFO correlated with EMG with spasms

• Augmentation of HFO preceded the onset of spasms seen mainly in Rolandic cortex

• Post-surgical outcomes better if maximal HFO resected

Page 15: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Down’s syndrome based model of IS• Model of infantile spasms created by exposing

Down’s mice to a GABA B agonist such as baclofen or GHB. Note these mice overexpress (g-coupled inward rectifying potassium channels) specifically GIRK 2 channels

• GIRK 2 KO Down’s mice are resistant to GIRK channel agonist-induced spasms- thus there is a specific molecular target for developing treatments of IS

Cortez MA et al 2009, Joshi K et al 2016

Page 16: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Cortez MA et al 2009, Joshi K et al 2016

WT

Ts65Dn

Ts65Dn + GBL- interictal

Ts65Dn + GBL- ictal

Page 17: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Ultra slow oscillations common around

time of spasms

The USO are due to GIRK channel

over activity

Page 18: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

NMDA-Induced Motor Seizures Following Prenatal Betamethasone

Velisek et al, Ann Neurol 2007

Baseline

After NMDA

After NMDA

Page 19: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Effects of ACTH on Latency to NMDA-evoked Events

Velisek et al, Ann Neurol 2007

Naïve Rats

Prenatal Exposureto Betamethasone

Model of NMDA induced spasms in the stressed

brain sensitive to ACTH

Page 20: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Upregulation of MC4 receptors in the hypothalamus in rats with spasms- if blocked

pharmacologically then ACTH is no longer effective

Immunohistochemistry Western blot

Inching closer to

knowing the exact

mechanism and site

of action of ACTH

Page 21: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Development of the triple-hit model of infantile spasms based on

our best understanding of the mechanisms

• Hypothesized that spasms occur in patients with both abnormal cortical and brainstem function and/or abnormal communication between the two structures as can occur due to white matter injury

• Abnormal serotonerigic mechanisms would potentiate the spasms

Page 22: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Age : P9, Flexion spasm Age : P9, Extension spasm

DOXORUBICIN: TO INDUCE CORTICAL AND BRAINSTEM INJURY

LIPOPOLYSACCHARIDE: TO INDUCE INFLAMMATORY CASCADES

AND WHITE MATTER INJURY

PCPA: TO REDUCE SEROTONIN LEVELS

Scantlebury MH et al: Neurobiol Dis 2010

Multiple-hit model: Robust model that allows

for the rapid screening of drugs for IS

Page 23: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Scantlebury MH et al: Neurobiol Dis 2010

Page 24: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Scantlebury MH et al: Neurobiol Dis 2010

Page 25: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Autistic features and learning deficits

Scantlebury MH et al: Neurobiol Dis 2010

Page 26: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Scantlebury MH, et al: Neurobiol Dis 2010

Spasms refractory to ACTH – Paritaly Responsive to Vigabatrin

Page 27: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Ono et al 2010

Carisbamate, but not phenytoin, suppresses spasms acutely

Page 28: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Rapamycin suppresses spasms and improves cognitive outcome

Raffo et al 2010

Page 29: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Briggs et al Epilepsia 2014

Page 30: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,
Page 31: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Surface Righting

Postnatal age

P5 P6 P7 P9 P10 P11 P12

La

tency (

sec)

0

20

40

60

80

100Saline/ND

Saline/KD

Treatment/ND

Treatment/KD

Age: p=0.001; Treatment x Age: p=0.01

Open Field

Postnatal age

P5 P6 P7 P9 P10 P11 P12

La

ten

cy (

se

c)

0

20

40

60

80

100Treatment: p=0.006; Age: p<0.001; Treatment x Age: p=0.001

Negative Geotaxis

Postnatal age

P5 P6 P7 P9 P10 P11 P12

La

ten

cy (

se

c)

0

20

40

60

80

100Treatment: p=0.006; Age: p<0.001; Treatment x Age: p<0.001

Postnatal age

P4 P5 P6 P7 P8 P9 P10 P11 P12

Bo

dy w

eig

ht (g

)

8

10

12

14

16

18

20

22

24 ND/Saline

KD/Saline

ND/Treatment

KD/Treatment

Treatment: p<0.001Age: p<0.001Treatment vs Age: p<0.001

* *

#

* *

*

#

#

*

#

*

*,#: significant differences from ND/Saline

Scantlebury lab 2017 unpublished

Page 32: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Pedro R. Olivetti et al., Sci Transl Med 2014; Chachua T et al, Epilepsia 2016

• E2 treatment

prevent spasms

and long-term

seizures, restores

GABAergic INs

• Not observed in

model of NMDA –

induced spasms

• Arrested decent

of the testes and

changes in sex-

specific behaviors

a side effect

Page 33: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

MODLES Method Age Seizure type Ictal EEG Inter Ictal EEG Treatments

Acquired

CRH** i.c.v. injections of CRH P5-16 Limbic like

seizures(

Chewing)

Swimming, Leg

clonus,

Tonic limb

posturing

Semi rhythmic sharp wave and

increased beta activity

- Effective: Phenytoin, alpha

helical CRH

Ineffective: ACTH

NMDA** i.p. injections of NMDA P12-18 Tail twisting,

spasms

Suppression of activity or

“serrated waves” which is runs

of slow waves with

superimposed fast activity

- Effective: Vigabatrin (P12), VPA

(P18), B6, (P12 and P18)

Ineffective: VPA (P12), ACTH

Betamethasone-

NMDA**

i.p. injections of NMDA in

pups prenatally exposed to

betamethasone

P15 Tail twisting,

spasms

Suppression of activity or

“serrated waves” which is runs

of slow waves with

superimposed fast activity

- Effective:ACTH

TTX** Infusion of TTX into cortex

and hippocampus

P21-adults spasms High amplitude slow wave

transient followed by attenuation

with superimposed fast activity

Multi-focal spikes and

sharp wave discharges

None tested

Genetic

Down’s* i.c.v injection of GHB to the

Ts(1716)65Dn mouse

P7 to adults spasms Bursts of epileptiform activity

followed by attenuation

Generalized voltage

attenuation

Effective: ACTH1-24, CGP

354348, ethosuxamide,

valproate, Vigabatrin (partially)

Ineffecttive: ACTH1-39,

Serotonin, baclofen, (latter two

exacerbate the seizures)

ARX* Conditional knock-out Adults spasms spike wave discharge followed

by voltage attenuation on the

EEG

Reduced delta and beta

activity

None tested

ARX(GCG)10+7* Triplet repeat knock in

expansion

P7-11 spasms sharp transient followed by

attenuation of the background

activity

High amplitude spike –

slow wave discharges

Estradiol

Page 34: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

IS lies along a spectrum of the DEEDs

EIEE IS LGS

Page 35: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Comparison of the clinical feature of the epileptic encephalopathies

Clinical features EIEE EME IS LGS

Age at onset 75% < 1 month 96% < 1 month 90% 3-12 months 1-7 years

Incidence/10,000

live births

Rare (unknown) Rare (unknown) 3-5 2.8

Seizure Types Tonic spasms*

Partial motor

Erratic focal motor

Hemiconvulsions

Generalized tonic

Erratic/fragmentary

myoclonus *

Tonic

Tonic spasms (rare)

Simple focal

Spasms (flexor, extensor, mixed

flexor/extensor) *

Focal

Drop attacks

Tonic (80-90%)*

Atypical absence

Atonic

Drop attacks

Non-convulsive status

Ictal EEG Burst Suppresion

Attenuation

No clear correlate Electrodecremental (attenuation

+/- with overriding fast activity)

Paroxysmal fast

Attenuation

Slow spike wave discharges

Combination

Inter Ictal EEG Burst Suppresion Burst Suppresion Hypsarrhythmia Slow spike wave discharges

Prognosis Poor Poor Etiology dependent Poor

Treatment Non- effective

Zonisamide,

Vigabatrin in

single case

reports

Non-effective. Pyridoxine

in those due to pyridoxine

deficiency

ACTH, Vigabatrin in some

patients

Often intractable. Polytherapy often

applied.

Page 36: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

EIEE

EME IS

Page 37: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

LGS

Page 38: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Etiologies of the catastrophic epilepsies

Etiology EIEE EME IS

Structural abnormalities,

acquired or genetic

Cerebral dysgenesis

Aicardi syndrome

Hemimegalencephaly

Lissencephaly

Porencephaly

Hydrocephalus

Subacute Diffuse

Encephalopathy

Rare HIE, birth trauma

Stroke, Hemorrhage

Meningitis , encephalitis, congenital

infections

Focal cortical dysplasia

Tuberous sclerosis

Aicardi syndrome

Periventricular nodular heterotopia

Subcortical band heterotopia

Polymicrogyria

Hemimegencephaly

Lissencephaly

Pachygyria

Microdysgenesis

Holoprosencephaly

Inborn errors of metabolism

/mitochondrial disorders

Many genetic causes

emerging

Non-ketotic hyperglycinemia,

Propionic aciduria,

Methyl melonic academia ,

d-Glyceric academia,

Sulphite defficiency

xantnine deficiency

Menke’s disease,

Molybdenum co-factor

deficiency

Zellweger’s syndrome,

Pyridoxine dependency

Tay Sach’s (phenylketonuria)

dihydropteridine reductase deficiency

Histidinemia

Pyridoxine dependency

Urea cycle disorders

Alpers syndrome

Leighs syndrome (cytochrome c oxidase

deficiency)

Other chromosomal

abnormalities

Down’s syndrome (Trisomy 21)

ARX

Page 39: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

….therefore the knowledge gained from

understanding one model may be applicable

across the spectrum of etiologies of the epileptic

encephalopathies….

Page 40: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Conclusion

• There is major recent advances in the understanding of the epileptic encephalopathies that would lead to new, safe and effective etiology specific treatments which are urgently needed clinically

Page 41: Rodent models of infantile spasms and the hunt for new ... - … · Rodent models of infantile spasms and the hunt for new treatments Morris H. Scantlebury M.D. Assistant Professor,

Thanks …

• Past and present Lab members:– Dr. Morris Scantlebury

– Dr. Karlene Barrett

– Ms Anamika Choudhary

– Mr Lucas Scott

– Ms Keelin Rivard

• Funding:

– ACHRI start-up funds

– ACHRI postdoctoral fellowship (Karlene)

– ACRI-BDB theme group bridge funding

– CSMREP

– CIHR Project scheme

• Collaborators:– Dr. Richard Wilson

– Dr. Quentin Pittman

– Dr. Arijit Roy