valrerio carelli - convegno mitocon 2014
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L’apparato visivo nei pazienti mitocondriali: le disfunzioni ed i trattamenti
Valerio Carelli, MD, PhD
IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
Neurology Unit, Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
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V
LUUR
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P E
LCUN SAGY
H
ND5 ND6
ND4
ND4L
ND3 R
COIII G
ATPase6/8 K COII D
SUCN
COI
A N C Y
W
ND2
I M
Q
ND1
16S
12S D-loop Cyt.b
D E
L
E
T
I
O N
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3243A->G MELAS CPEO DDM
tRNA-Ile mutations CARDIOPATHY
8344A->G MERRF
tRNA-Ser mutations DEAFNESS
1555A->G DEAFNESS (aminoglycosides)
cyt. b mutations MYOGLOBINURIC MYOPATHY
8993T->G NARP/MILS
3460G-A 11778G->A 14484T->C LHON
PEO, KSS, Pearson
Leber Hereditary Optic Neuropathy (mtDNA)
Dominant optic atrophy (OPA1) Recessive optic atrophy X-linked optic atrophy
Mito-pathways to RGCs loss OXPHOS deficiency (complex I) Reactive oxygen species (ROS) – calcium handling (mito-ER) Mito-dynamics-biogenesis-mitophagy Mitochondrial apoptosis
NATURAL HISTORY OF LHON Barboni et al., Ophthalmology 2010
A specific pattern of neurodegeneration
The pattern of neuro-degeneration follows the axonal diameter starting from the
smallest fibers on the temporal quadrant(papillo-macular bundle)
The smallest fibers are the most vulnerable in maintaining the energy supply because their volume is limited in accommodating
more mitochondria to compensate
CONTROL LHON/3460
A B C
D E F
Abnormal myelin maintenance
10 µm
10 µm
A B C
D E F
A B
What is the role of myelin maintenance in triggering RGCs loss or promoting RGCs sparing and function?
-Axonal swelling, -Increase of abnormal mitochondria -Thinning of myelin
-Preferential loss of smallest axons
Mouse model of OPA1 haploinsufficiency (Prof. Luca Scorrano)
COMMON THEMES LINKING RGC LOSS IN MITOCHONDRIAL OPTIC NEUROPATHIES
mtDNA mutations: -OXPHOS (complex I) deficiency -increased ROS -mito-fragmentation -activated biogenesis/mitophagy -myelin pathology -vascular changes
nDNA mutations: -OXPHOS (complex I/supercomplex) deficiency -increased ROS -mito-fragmentation -activated biogenesis/mitophagy -myelin pathology
pathologic axonal transport and ultimately APOPTOSIS of RGCs
Mitochondrial optic neuropathies are a convenient model for clinical trials: -only one tissue affected -fairly well understood pathogenesis and relatively predictable natural history -good quantitative outcome measures (visual acuity, visual fields, OCT assessments of retinal fiber layer thickness, etc.) -animal models available (OPA1 and ND6 mutants)
THERAPY FOR LHON and DOA
• Antioxidant - Idebenone and EPI-743 in affected • Activation of mitochondrial biogenesis for carriers • Anti-apoptotic drugs for acute phase • Gene therapy for LHON and NARP: allotopic
expression • Gene therapy: xenotopic expression of alternative
oxidase (S. Cervisiae single subunit NADH oxidase Ndi1)
• Gene therapy for DOA: in haploinsufficiency, AAV-dependent delivery of OPA1
Idebenone in LHON (and DOA)
New LHON trial with idebenone in UK (Dr. Patrick Yu-Wai-Mann), with high dosages and for a longer time!
EPI-743
*Eye from this patient was excluded #Eye did not experience vision loss
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Months of Treatment
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Figure 1. Mean deviation, logMar visual acuity and OCT average retinal nerve fiber layer from the 1st affected eye – from baseline to 24 months of EPI-743 therapy
Sign
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Figure 3. Examples of Humphrey visual fields at baseline and after 24 months of treatment
Baseline 24 months after treatment A.
C.
E.
B.
D.
F.
Figure 4. Examples of color optic disc photographs at baseline and after 24 months of treatment.
Baseline 24 months after treatment A.
C.
E.
B.
D.
F.
RNFL thickness between treated and untreated LHON patients
Pretreatment 24-months 18-months 12-months
EPI-743
Untreated affected LHON
patients
97.8 64.3 65.0 67.8 50.4
Not statistically significant
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�Marked improvement � Mild improvement � No improvement
OC
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NFL
1st eye
Baseline
24 months after treatment
RNFL swelling as a negative prognostic marker for LHON patients on therapy
*Definition of baseline: 6 months from vision loss
The greater the initial RNFL swelling, the worse the final outcome for the 1st eye after 24 months with EPI-743 treatment
THERAPY FOR LHON and DOA
• Antioxidant - Idebenone and EPI-743 in affected • Activation of mitochondrial biogenesis for carriers • Anti-apoptotic drugs for acute phase • Gene therapy for LHON and NARP: allotopic
expression • Gene therapy: xenotopic expression of alternative
oxidase (S. Cervisiae single subunit NADH oxidase Ndi1)
• Gene therapy for DOA: in haploinsufficiency, AAV-dependent delivery of OPA1
Females are partially protected in LHON
Oestrogens activate mito-biogenesis
Conclusions Oestrogens present a multilayer effect on complex I defective LHON cybrids, leading to: -reduced ROS production
-small but significant improvement in cybrids energetic competence -partial rescue of cell viability in galactose medium by restoring membrane potential and limiting apoptotic cell death -coordinated activation of mitochondrial biogenesis
THERAPY FOR LHON and DOA
• Antioxidant - Idebenone and EPI-743 in affected • Activation of mitochondrial biogenesis for carriers • Anti-apoptotic drugs for acute phase • Gene therapy for LHON and NARP: allotopic
expression • Gene therapy: xenotopic expression of alternative
oxidase (S. Cervisiae single subunit NADH oxidase Ndi1)
• Gene therapy for DOA: in haploinsufficiency, AAV-dependent delivery of OPA1
Dubbi sull’efficienza della metodica
Ancora risultati controversi
• We took advantage of cell models harboring the homoplasmic disruptive m.3571insC MTND1 mutation. We thereby demonstrated that allotopic expression of corrected mtDNA-encoded ND1 subunit complements and allows reassembly of human respiratory complex I along with recovery of bioenergetic deficiency, hence providing definitive proof that the allotopic expression is a feasible approach for gene therapy of mitochondrial diseases.
Strategie per la LHON • Terapia preventiva in fase pre-sintomatica:
attivatori della biogenesi mitocondriale nei carriers di mutazione non affetti e terapia genica
• Terapia in fase acuta: combinazione di farmaci
antiapoptotici (ciclosporina etc..?) e antiossidanti (idebenone e EPI-743) o terapia genica
• Terapia in fase cronica: antiossidanti (idebenone e
EPI-743) e attivatori della biogenesi mitocondriale e/o terapia genica
Thanks for the attention and thanks to the many collaborators: • Alfredo A. Sadun, USC, Los Angeles • Rubens Belfort Jr, UNIFESP, Sao Paolo • Carla Giordano, University “La Sapienza”, Rome • Palmiro Cantatore, University of Bari, Bari • Anna Ghelli, University of Bologna, Bologna • Pio D’Adamo, University of Trieste, Trieste • Vamsi Mootha, Harvard, Boston • Massimo Zeviani, MRC, Cambridge • Patrick Chinnery and Patrick Yu-Wai-Man, University of Newcastle, Newcastle • Piero Barboni, San Raffaele, Milano
• Lab of Neurogenetics: Alessandra Maresca, Leonardo Caporali, Sabrina Farne’, Chiara La Morgia, Maria Lucia Valentino
Melanopsin expressing retinal ganglion cells (mRGCs) survive in LHON and DOA
Melanopsin RGCs and conventional RGCs are loaded with mitochondria
mRGC
mRGC
RGC
RGC
RGC
RGC
Courtesy Fred Ross Cisneros and Carla Giordano
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