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Posts tagged ‘Ophthalmology’

Due to the pressure of other commitments, I only had the pleasure of attending the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO) for two days, but one of my key take home messages from the meeting is how we can use the eye as a window into the brain.  This is particularly relevant to Alzheimer’s research.

ARVO researchers at a lunchtime workshop that I attended asked the question of what can we learn from shared disease mechanisms in age-related macular degeneration (AMD), Alzheimer’s Disease (AD) and Glaucoma to devise therapies of the future?

What I learnt in the introduction by Nicholas Bazan from LSU Health Sciences is that both AD and AMD are both multifactorial, genetically complex, progressive, late-onset neurodegenerative conditions.  Common features include:

  1. Age-related neurodegeneration
  2. Amyloid precursor protein mis-processing
  3. Non-resolving inflammatory response
  4. Selective apoptotic cell death

Researchers in the workshop presented early experimental findings.

Catherine Bowes Rickman from Duke presented data that showed anti-amyloid immunotherapy blocks retinal pigment epithelium (RPE) damage and visual function defects in an AMD-like mouse model.  Interesting questions were raised as to whether mouse Aß aggregates differently to human, so is this a good model?

Adriana Di Polo from the University of Montreal discussed Glaucoma and AD: common neurodegenerative pathways and therapeutic targets. It was interesting to note that high rates of visual abnormalities, including glaucoma, have been reported in AD patients, but causality has not been established. Neuronal loss in both glaucoma and alzheimer’s disease occurs via common cell death processes including altered metabolism of Amyloid Precursor Protein (APP) and Aß.

What Di Polo highlighted in her talk was the potential to use therapies effective in one disease to treat the other e.g. galantamine is approved for treatment of mild to moderate AD symptoms.  Because it crosses the retinal-brain barrier and has high bioavailability, she presented results using this in an animal model of glaucoma.

Her conclusion was that “therapeutic modalities that promote neuroprotection in AD may be useful in glaucoma and vice versa.”

The third speaker of this fascinating workshop was Ian Trounce from Melbourne, who challenged the Amyloid theory of AD. His hypothesis was that sAPPα may trigger oxidative stress in mitochondria and be the problem. He discussed the increasing acceptance/overlap in pathologies between Parkinson’s and AD.  He presented data that sAPPα overexpression protects retinal ganglion cells (RGC) from rotenone via PI3K-AKT activation.

Critical feedback on the three presentations was provided by Guy Eakin of the American Health Assistance Foundation (AHAF) and Imre Lengyel from UCL.

As Dr Lengyel succinctly notes in his UCL Institute of Ophthalmology bio:

“It appears that the development of age related macular degeneration (AMD) and Alzheimer’s disease (AD) share similar histopathology, vascular risk factors and genetic predisposition. In addition, the development of AMD appears to use similar or identical steps on the cellular and molecular levels to AD: vascular damage, oxidative stress, inflammation, extracellular protein and peptide degradation or deposition, and the role for lipids and trace elements (especially zinc) in the degenerative process are amongst the many common features. Furthermore, amyloid beta peptides are an integral part of drusen (the hallmark lesion in AMD) and their formation might be similar to plaque formation in AD.”

I applaud ARVO for looking at how the eye can be used as a window into the brain. It raises the intriguing prospect that research on AMD may not only help understand the cause of AD, but that the eye may serve as an experimental model for future new treatments. Collaboration between Opthalmology and Alzheimer’s researchers is something I expect and hope we will see more of.

 

There is a lot of innovative research being presented at the Association for Research in Vision and Ophthalmology (ARVO) annual meeting here in Fort Lauderdale.

For those unable to attend, a large number of poster presentations are now available online with free access.

Not all posters are being made available electronically, only a select few have been invited by the Program Committee, and not every presenter invited has made their poster available.

The online electronic posters will be added to over the next few days of the conference after they have been presented.  I am impressed that ARVO have made this information publicly available at no cost through June 30th.

For those interested the link to the available ARVO 2011 electronic posters can be found on the ARVO website, or you can click here.

The selected posters provide a window into ophthalmology and vision research and are well worth viewing.

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There is a lot of buzz this week about Lucentis versus Avastin for the treatment of wet age-related macular degeneration (AMD), something that will be talked about in more detail at the Association for Research in Vision and Ophthalmology (ARVO) annual meeting this weekend in Fort Lauderdale.

Also on the radar at ARVO is more news from Second Sight and their Argus II Retinal Prosthesis (something that I have previously written about on this blog).  For those interested there is a press conference at ARVO on Tuesday, May 3 from 5-6pm.

Second Sight presents updated results from the Argus II Retinal Prosthesis clinical trial, including sentence reading and color vision restoration for previously blind subjects. Two trial participants and independent investigators from the trial will be available for interviews.

Which brings me back to a Nature article published earlier this month that I have been meaning to write about showing, for the first time, the ability to generate a three-dimensional culture of neural retinal tissue from mouse embryonic stem (ES) cells.  A word of warning, you may find the paper a little tough to follow unless you are a scientist in this field.

Eiraku and colleagues from Japan were able to culture retinal tissue similar to that seen in the human eye.  Eye formation starts as an optical vesicle that then develops into a two-walled optic cup.  As the authors note “optic cup development occurs in a complex environment affected by neighbouring tissues.”

What the authors showed in their research was the ability to culture retinal tissue containing ganglion cells, photoreceptors and bipolar cells.  They conclude:

Collectively, these findings demonstrate that the fully stratified neutral retina tissue architecture in this ES-cell culture self-forms in a spatiotemporally regulated manner mimicking in-vivo development.

My take on this research is that it is an important milestone in regenerative medicine that could lead to the prospect of retinal transplants in the future.  I look forward to learning more at ARVO about what the future may hold for retinal transplants derived from human stem cells.

ResearchBlogging.orgEiraku, M., Takata, N., Ishibashi, H., Kawada, M., Sakakura, E., Okuda, S., Sekiguchi, K., Adachi, T., & Sasai, Y. (2011). Self-organizing optic-cup morphogenesis in three-dimensional culture Nature, 472 (7341), 51-56 DOI: 10.1038/nature09941

This weekend I will be at the annual meeting of The Association for Research in Vision and Ophthalmology (ARVO) in Fort Lauderdale.

I’m excited about attending because earlier in my career I worked at Alcon Laboratories on European IDE clinical trials for three novel intra-ocular lenses.

ARVO is the ophthalmology equivalent of AACR and is where scientists involved in drug, device research meet to discuss new findings and early stage research.

The title of meeting is “Visionary Genomics.”  After listening to the plenary session at the recent AACR annual meeting by Lynda Chin on how insights from cancer genomics are translating into personalized medicine, I’m looking forward to seeing the impact of genomics on vision research.

Sunday’s ARVO/Alcon keynote presentation is from Roderick McInnes who is the Canada Research Chair in Neurogenetics at McGill University in Montreal.

A presentation that is already generating some advance interest is Sunday’s presentation of the results from the Comparison of Age Related Macular Degeneration Treatments Trials (CATT).

Age related macular degeneration (AMD) is the leading cause of vision loss in those over 65 in the United States, with over 7 million people estimated to be at risk.  Once you have AMD in one eye, you have a 43% risk of developing it in the other eye over a  five year period, a scary statistic!

The first CATT clinical trial is between bevacizumab (Avastin®) and ranibizumab (Lucentis®), both similar anti-VEGF inhibitors that are derived from the same monoclonal antibody.  It will be interesting to see whether the data supports the current practice of off-label use of bevacizumab given its lower cost compared to ranibizumab.

The findings from this data will also potentially impact aflibercept (VEGF-Trap) that is being co-developed by Bayer and Regeneron.  In February, Regeneron submitted a biologics license application (BLA) to the FDA for the use of VEGF-Trap in wet AMD.

The initial results from the aflibercept phase III AMD trial announced late last year showed a non-inferiority to ranibizumab.  If aflibercept is approved and comes to market in 2012, depending on the CATT results, it may have to compete on price against off-label bevacizumab in AMD.  Whether a more convenient injection once every two months for VEGF-Trap (compared to monthly for Lucentis) is sufficient to justify a price premium, it will be interesting to watch the market dynamics in this space.

You can find more about the meeting on the ARVO conference website and they have also put up a blog for the meeting.   The theme of my blog posts over the next few days will be ophthalmology related, and I expect to be live tweeting from ARVO 2011 on Sunday and Monday.  I’ll also be aggregating tweets from the meeting (hashtag #ARVO11) on this blog.

 

Human eye cross-sectional view. Courtesy NIH N...Image via Wikipedia

VEGF Trap-Eye is a formulation of VEGF Trap (aflibercept) and is an anti-angiogenic agent that can be injected into the eye to stop the proliferation of blood vessels. Regeneron (REGN) are co-developing it with Bayer (BAY) and it is currently in clinical trials for the treatment of wet Age-Related Macular Degeneration (AMD), Diabetic Macular Edema (DME) and Central Retinal Vein Occlusion (CRVO).

Phase II DME clinical trial results presented at the
Angiogenesis 2010 meeting in Miami showed the primary endpoint of a
statistically significant increase in visual acuity over 24 weeks compared to
the standard of care (laser treatment) was met.

There are high levels of vascular endothelial growth factor (VEGF) associated with DME, so the news that VEGF Trap-Eye has biological activity in this disease is positive.What makes this data promising is the fact that DME is the leading cause of blindness in adults under 50 and there are 370,000 Americans with clinically significant DME with 95,000 new cases a year.

The ability to treat DME by an eye injection, rather than use an expensive laser will make it easier to treat the disease. It will be interesting to see what how the cost of treatment with VEGF Trap-Eye compares to laser therapy procedures, should the agent make it to market.

The recent pricing issue faced by Genentech with its VEGF inhibitors Lucentis
(eye indications) and Avastin (oncologic indications) are also relevant because
Regeneron are developing VEGF-Trap in cancer with it’s partner sanofi-aventis
(a client).

For VEGF Trap-Eye, Regeneron retains all U.S. marketing
rights, while Bayer has rights to market ex-US in return for a 50/50 profit
share with Regeneron.The results so far look promising and aflibercept looks like an interesting agent well worth watching as the development moves forward.

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