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INTRODUCING NEW CONCEPTS
IN CORNEAL SURGERY
Miltos Balidis MD,PhD,FEBOphth, President of SECRS
Cairo 2019
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• Αλκμαίων
• Εμπεδοκλής
• Ηρόφιλος
• Ερασίστρατος
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Life needs …..
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Vision
• Obstacles are those frightful things you
see when you take your eyes off the
goal."
. » Hannah More
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Cairo 2019
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Stromal Opacity
Alternative
strategies of
Replacement or
Removal
Replacing stroma sparing
the endothelium
DALK , FALK
Replacing with
synthetic optical
elements /
keratoprosthesis
Replacement with
Biomimetic or
bioengineered material
Acellular or cellularized
scaffold, Acornea
Regeneration of stromal
transparency with stem
cell remodeling
MSC,ESC,iPSC
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Stromal multipotent stem cells
in the limbus
Stromal stem cells next
to basal epithelial cells
Limbal biopsies contain
Stromal Stem Cells
Stromal stem cells differentiate into
keratocytes and remodel
disorganized stroma
Remodeling of stromal
scars by keratocytes,
restores transparencyStromal stem cells
1. Regenerate corneal stroma
2. Remodel activate corneal
wounds
3. Differentiate into keratocytes
4. Prevent and reverse scarring
Cairo 2019
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Topical Hepatic Growth Factor alone is Sufficient
to restore corneal transparencyin Ocular Injury
Cairo 2019
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Pluripotent stem cell
(iPS) transplantation
• Are the cells identical to the original cells?
• How long do they remain effective
• Long term potential side effects?– Oxidative stress associated with reprogramming?
• Do we still need retroviruses?Hotspots of De Novo Point Mutations in Induced Pluripotent Stem Cells Yoshihara, M et al , Cell
Reports, vol. 21, no. 2, pp. 308–315, 2017
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Stromal Opacity
Alternative
strategies of
Replacement or
Removal
Replacing stroma
sparing the
endothelium
DALK , FALK
Replacing with
synthetic optical
elements /
keratoprosthesis
Replacement with
Biomimetic or
bioengineered material
Acellular or cellularized
scaffold, Acornea
Regeneration of
stromal transparency
with stem cell
remodeling
MSC,ESC,iPSC
Cairo 2019
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Stromal substitutes
• Acellular inert material impearmeable to cells
• Acellular biomaterial as scaffold
• Biomaterial enhanced with cells at production
• Stromal substitutes entirely engineered from cells
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Tissue-engineered stromal substitute
Guo 2007,
Karamichos 2014
Karamichos 2013
Du 2010,Wu2014
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TE cornea
• Minimum risk of rejection
• Minimum need for post-surgical drugs
• Better biocompatibility and integration than
the synthetic corneas permanent corneas,
• Cost-effective
• Readily available to patients.
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1818 F Reisingeranimal keratoplasty
1835 Bigger successful PKP in pet
1838 Kisamtherapeutic xenon graft on human
1867 Power PKP with allograft
1888Von HippelLamellar xenograftsclockwise trephane
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Why DC
• DCs are potentially advantageous in
comparison to TE corneal equivalents and
KPros• the matrix has the ultrastructure of the native tissue.
• Inherent biological signals may remain within the
matrix, important for the maintenance of specific
cellular functions and phenotype
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Enzymes
• Trypsin
• Dispase
• Phospholipidases A2-PLA2
• Nucleases
• Sera
• EDTA
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Chemicals
• Alcohols
• Acid-Alcali
• Ionic Detergents • SDS
• SD
• Non ionic Detergents• Triton X
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Osmotic and Physical
• Hypo or hypertonic solutions
• Freeze thawing
• Hydrostatic pressure
• Sonication
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Decellularization
ECM, GAG’s, proteins
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Get the balance right
Cairo 2019
antigens ECM
Removal of antigens
important for graft
rejection and
inflammation
Maintaining ultrastructural
architecture
Intact ECM, proteins,
GAG’s, and biological
signals for keratocytes
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Cryolyophilized
KeratoxenograftsOdessa Institute of Eye Diseases and Tissue Therapy
•Processing with a cryoprotector
•Preserved at cryogenic temperatures (-196 ° C),
•Vacuum dryed and packaging
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Acornea
• The Acornea is a heterogeneous cornea.
• Stripped of cells, hybrid proteins and other
antigens, maintaining its natural collagen
structure.
• Able to integrate with the surrounding tissue
and foster the regeneration of its own cells.
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Generation of Bioengineered Corneas with Decellularized Xenografts and Human KeratocytesInvest. Ophthalmol. Vis. Sci.. 2011;52(1):215-222. doi:10.1167/iovs.09-4773
Analysis of NPC (top
row) and corneas
decellularized with 1.5 M
NaCl (middle row) and
0.1% SDS (bottom row).
First column: H&Eof
anterior and posterior
corneas; second column:
fiber orientation analysis
with polar plot images;
third column: azimuthal
images; fourth column:
Alcian blue staining of the
different samples; fifth
column: fluorescence
immunohistochemistry
against α-gal epitope.
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