Macular degeneration

Lab-made retinas offer a new approach to battling vision loss

/ Kevin McCormack / 3 Comments

Age-related macular degeneration (AMD) is the leading cause of vision loss in the elderly. Now, new research using 3D organoid models of the eye has uncovered clues as to what happens in AMD, and how to stop it. 

In AMD, a person loses their central vision because the light sensitive cells in the macula, a part of the retina, are damaged or destroyed. This impacts a person’s ability to see fine details, recognize faces or read small print, and means they can no longer drive. 

AMD causes blurry and distorted vision 

No one is quite sure what causes AMD, but in a study in the journal Nature Communications, German researchers used miniature human retina organoids to get some clues.  

Building a better model for research

Organoids are 3D models made from human cells that are grown in the lab. Because they have some of the characteristics of a human organ—in this case the retina—they help researchers better understand what is happening in the AMD-affected eye. 

In this study they found that photoreceptors, the light sensitive cells at the back of the retina, were missing but there was no sign of dead cells in the organoid. This led them to suspect that something called cell extrusion was at play.  

Cell extrusion is where a cell exports or sends large particles outside the cell. In this case it appeared that something was causing these photoreceptors to be extruded, leading to the impaired visual ability.  

In a news release Mark Karl, one of the authors of the study, said, “This was the starting point for our research project: we observed that photoreceptors are lost, but we could not detect any cell death in the retina. Half of all photoreceptors disappeared from the retinal organoid within ten days, but obviously they did not die in the retina. That made us curious.” 

Using snakes to fight AMD 

Further research identified two proteins that appeared to play a key role in the process, triggering the degeneration of the retinal organoid. They also tested a potential therapy to see if they could stop the process and save the photoreceptors. The therapy they tried, a snake venom, not only stopped the photoreceptors from being ejected, but it also prevented further damage to the retinal cells. 

Karl says this is the starting point for the next step in the research. “This gives hope for the development of future preventive and therapeutic treatments for complex neurodegenerative diseases such as AMD.” 

CIRM’s fight against blindness 

The California Institute for Regenerative Medicine (CIRM) has funded six clinical trials targeting vision loss, including one for AMD. We recently interviewed Dr. Dennis Clegg, one of the team trying to develop a treatment for AMD and he talked about the encouraging results they have seen so far. You can hear that interview on our podcast “Talking ‘Bout (re)Generation.” 

Study shows sleep deprivation impairs stem cells in the cornea 

/ Esteban Cortez / 1 Comment

We spend around one third of our life sleeping—or at least we should. Not getting enough sleep can have serious consequences on many aspects of our health and has been linked to high blood pressure, heart disease and stroke. 

A study by the American Sleep Apnea Association found that some 70 percent of Americans report getting too little sleep at least one night a month, and 11 percent report not enough sleep every night. Over time that can take a big toll on your mental and physical health. Now a new study says that impact can also put you at increased risk for eye disease.  

The study published in the journal Stem Cell Reports, looked at how sleep deprivation affects corneal stem cells. These cells are essential in replacing diseased or damaged cells in the cornea, the transparent tissue layer that covers and protects the eye.  

Researchers Wei Li, Zugou Liu and colleagues from Xiamen University, China and Harvard Medical School, USA, found that, in mice short-term sleep deprivation increased the rate at which stem cells in the cornea multiplied. Having too many new cells created vision problems.  

They also found that long-term sleep deprivation had an even bigger impact on the health of the cornea. Sleep-deprived mice had fewer active stem cells and so were not as effective in replacing damaged or dying cells. That in turn led to a thinning of the cornea and a loss of transparency in the remaining cells.  

The cornea— the transparent tissue layer covering the eye—is maintained by stem cells, which divide to replace dying cells and to repair small injuries.

The findings suggest that sleep deprivation negatively affects the stem cells in the cornea, possibly leading to vision impairment in the long run. It’s not clear if these findings also apply to people, but if they do, the implications could be enormous.  

The California Institute for Regenerative Medicine (CIRM) is also heavily involved in searching for treatments for diseases or conditions that affect vision. We have invested almost $150 million in funding 31 projects on vision loss including a clinical trial with UCLA’s Dr. Sophie Deng targeting the cornea, and other clinical trials for age-related macular degeneration and retinitis pigmentosa. 

Shared with permission from International Society for Stem Cell Research. Read the source release here. 

How a tiny patch is helping restore lasting vision

/ Kevin McCormack / 4 Comments

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Researchers are working on a stem cell-based retinal implant that could be used for people with with advanced dry age-related macular degeneration. (Photo/ Britney O. Pennington)

When Anna Kuehl began losing her vision, she feared losing the ability to read and go on long walks in nature—two of her favorite pastimes. Anna had been diagnosed with age-related macular degeneration, the leading cause of vision loss in the US. She lost the central vision in her left eye, which meant she could no longer make out people’s faces clearly, drive a car, or read the time on her watch.

Anna Kuehl

But a clinical trial funded by the California Institute for Regenerative Medicine  (CIRM) helped change that. And now, new data from that trial shows the treatment appears to be long lasting.

The treatment sprang out of research done by Dr. Mark Humayun and his team at USC. In collaboration with Regenerative Patch Technologies they developed a stem cell-derived implant using cells from a healthy donor. The implant was then placed under the retina in the back of the eye. The hope was those stem cells would then repair and replace damaged cells and restore some vision.

Dr. Mark Humayun, photo courtesy USC

In the past, using donor cells meant that patients often had to be given long-term immunosuppression to stop their body’s immune system attacking and destroying the patch. But in this trial, the patients were given just two months of immunosuppression, shortly before and after the implant procedure.

In a news story on the USC website, Dr. Humayun said this was an important advantage. “There’s been some debate on whether stem cells derived from a different, unrelated person would survive in the retina without long-term immunosuppression. For instance, if you were to receive a kidney transplant, long-term immunosuppression would be required to prevent organ rejection. This study indicates the cells on the retinal implant can survive for up to two years without long-term immunosuppression.”

Cells show staying power

When one of the patients in the clinical trial died from unrelated causes two years after getting the implant, the research team were able to show that even with only limited immunosuppression, there was no evidence that the patient’s body was rejecting the donor cells.

“These findings show the implant can improve visual function in some patients who were legally-blind before treatment and that the cells on the implant survive and remain functional for at least two years despite not being matched with those of the patient,” Humayun said.

For Anna Kuehl, the results have been remarkable. She was able to read an additional 17 letters on a standard eye chart. Even more importantly, she is able to read again, and able to walk and enjoy nature again.

Dr. Humayun says the study—published in the journal Stem Cell Reports—may have implications for treating other vision-destroying diseases. “This study addresses the debate over the viability of using mismatched stem cells — this shows that a mismatched stem cell derived implant can be safe and viable over multiple years.”

Sometimes a cold stare is a good thing

/ Kevin McCormack / 6 Comments
A retina of a patient with macular degeneration. (Photo credit: Paul Parker/SPL)

Age-related macular degeneration (AMD) is the leading cause of vision loss and blindness in the elderly in the U.S. It’s estimated that some 11 million Americans could have some form of the disease, a number that is growing every year. So if you are going to develop a treatment for this condition, you need to make sure it can reach a lot of people easily. And that’s exactly what some CIRM-supported researchers are doing.

Let’s back up a little first. AMD is a degenerative condition where the macular, the small central portion of your retina, is slowly worn away. That’s crucial because the retina is the light-sensing nerve tissue at the back of your eye. At first you notice that your vision is getting blurry and it’s hard to read fine print or drive a car. As it progresses you develop dark, blurry areas in the center of your vision.

There are two kinds of AMD, a wet form and a dry form. The dry form is the most common, affecting 90% of patients. There is no cure and no effective treatment. But researchers at the University of Southern California (USC), the University of California Santa Barbara (UCSB) and a company called Regenerative Patch Technologies are developing a method that is looking promising.

They are using stem cells to grow retinal pigment epithelium (RPE) cells, the kind attacked by the disease, and putting them on a tiny synthetic scaffold which is then placed at the back of the eye. The hope is these RPE cells will help slow down the progression of the disease or even restore vision.

Early results from a CIRM-funded clinical trial are encouraging. Of the five patients enrolled in the Phase 1/2a trial, four maintained their vision in the treated eye, two showed improvement in the stability of their vision, and one patient had a 17-letter improvement in their vision on a reading chart. In addition, there were no serious side effects or unanticipated problems.

So now the team are taking this approach one step further. In a study published in Scientific Reports, they say they have developed a way to cryopreserve or freeze this cell and scaffold structure.

In a news release, Dr. Dennis Clegg of UCSB, says the frozen implants are comparable to the non-frozen ones and this technique will extend shelf life and enable on-demand distribution to distant clinical sites, increasing the number of patients able to benefit from such treatments.

“It’s a major advance in the development of cell therapies using a sheet of cells, or a monolayer of cells, because you can freeze them as the final product and ship them all over the world.”

Cool.

Helping the blind see – mice that is

/ Kevin McCormack / Leave a comment

When I first saw the headline for this story I thought of the nursery rhyme about the three blind mice. Finally, they’ll be able to see the farmer’s wife coming at them with a carving knife. But the real-world implications are of this are actually pretty exciting.

Researchers at the National Institute of Health’s National Eye Institute took skin cells from mice and directly reprogrammed them into becoming light sensitizing cells in the eye, the kind that are often damaged and destroyed by diseases like macular degeneration or retinitis pigmentosa.

What’s particularly interesting about this is that it bypassed the induced pluripotent stem cell (iPSC) stage where researchers turn the skin cells into embryonic-like cells, then turn those into the cells found in the eye.

In a news release, Anand Swaroop of the NEI says this more direct approach has a number of advantages: “This is the first study to show that direct, chemical reprogramming can produce retinal-like cells, which gives us a new and faster strategy for developing therapies for age-related macular degeneration and other retinal disorders caused by the loss of photoreceptors.”

After converting the skin cells into cells called rod photoreceptors – the light sensing cells found in the back of the eye – the team transplanted them into blind mice. One month later they tested the mice to see if there had been any change in vision. There had; 43 percent of the mice reacted to light exposure, something they hadn’t done before.

Biraj Mahato, the study’s first author, said that three months later, the transplanted cells were still alive and functioning. “Even mice with severely advanced retinal degeneration, with little chance of having living photoreceptors remaining, responded to transplantation. Such findings suggest that the observed improvements were due to the lab-made photoreceptors rather than to an ancillary effect that supported the health of the host’s existing photoreceptors.”

Obviously there is a lot of work still to do before we can even begin to think about trying something like this in people. But this is certainly an encouraging start.

In the meantime, CIRM is funding a number of stem cell programs aimed at treating vision destroying diseases like macular degeneration and retinitis pigmentosa.

You can bank on CIRM

/ Kevin McCormack / 2 Comments

Way back in 2013, the CIRM Board invested $32 million in a project to create an iPSC Bank. The goal was simple;  to collect tissue samples from people who have different diseases, turn those samples into high quality stem cell lines – the kind known as induced pluripotent stem cells (iPSC) – and create a facility where those lines can be stored and distributed to researchers who need them.

Fast forward almost seven years and that idea has now become the largest public iPSC bank in the world. The story of how that happened is the subject of a great article (by CIRM’s Dr. Stephen Lin) in the journal Science Direct.

Dr. Stephen Lin

In 2013 there was a real need for the bank. Scientists around the world were doing important research but many were creating the cells they used for that research in different ways. That made it hard to compare one study to another and come up with any kind of consistent finding. The iPSC Bank was designed to change that by creating one source for high quality cells, collected, processed and stored under a single, consistent method.

Tissue samples – either blood or skin – were collected from thousands of individuals around California. Each donor underwent a thorough consent process – including being shown a detailed brochure – to explain what iPS cells are and how the research would be done.

The diseases to be studied through this bank include:

  • Age-Related Macular Degeneration (AMD)
  • Alzheimer’s disease
  • Autism Spectrum Disorder (ASD)
  • Cardiomyopathies (heart conditions)
  • Cerebral Palsy
  • Diabetic Retinopathy
  • Epilepsy
  • Fatty Liver diseases
  • Hepatitis C (HCV)
  • Intellectual Disabilities
  • Primary Open Angle Glaucoma
  • Pulmonary Fibrosis

The samples were screened to make sure they were safe – for example the blood was tested for HBV and HIV – and then underwent rigorous quality control testing to make sure they met the highest standards.

Once approved the samples were then turned into iPSCs at a special facility at the Buck Institute in Novato and those lines were then made available to researchers around the world, both for-profit and non-profit entities.

Scientists are now able to use these cells for a wide variety of uses including disease modeling, drug discovery, drug development, and transplant studies in animal research models. It gives them a greater ability to study how a disease develops and progresses and to help discover and test new drugs or other therapies

The Bank, which is now run by FUJIFILM Cellular Dynamics, has become a powerful resource for studying genetic variation between individuals, helping scientists understand how disease and treatment vary in a diverse population. Both CIRM and Fuji Film are committed to making even more improvements and additions to the collection in the future to ensure this is a vital resource for researchers for years to come.

CIRM-funded study helps unlock some of the genetic secrets behind macular degeneration

/ Kevin McCormack / Leave a comment
Retina affected by age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of vision loss in people over 60. It affects 10 million Americans. That’s more than cataracts and glaucoma combined. The causes of AMD are not known but are believed to involve a mixture of hereditary and environmental factors. There is no treatment for it.

Now, in a CIRM-funded study, researchers at UC San Diego (UCSD) have used stem cells to help identify genetic elements that could provide some clues as to the cause, and maybe give some ideas on how to treat it.

Before we get into what the researchers did let’s take a look at what AMD does. At a basic level it attacks the retina, the thin layer of tissue that lines the back of the eye. The retina receives light, turns it into electrical signals and sends it to the brain which turns it into a visual image.

The disease destroys the macula, the part of the retina that controls our central vision. At first, sight becomes blurred or fuzzy but over time it progresses to the point where central vision is almost completely destroyed.

To try and understand why this happens the team at UCSD took skin samples from six people with AMD and, using the iPSC method, turned those cells into the kinds of cell found in the retina. Because these cells came from people who had AMD they now displayed the same characteristics as AMD-affected retinal cells. This allowed the researchers to create what is called a “disease-in-a-dish” model that allowed them to see, in real time, what is happening in AMD.

They were able to identify a genetic variant that reduces production of a protein called VEGFA, which is known to promote the growth of new blood vessels.

In a news release Kelly Frazer, director of the Institute for Genomic Medicine at UCSD and the lead author of the study, said the results were unexpected.

Kelly Frazer, PhD, UC San Diego

“We didn’t start with the VEGFA gene when we went looking for genetic causes of AMD. But we were surprised to find that with samples from just six people, this genetic variation clearly emerged as a causal factor.”

Frazer says this discovery, published in the journal Stem Cell Reports, could ultimately lead to new approaches to developing new treatments for AMD.

CIRM already funds one clinical trial-stage project targeting AMD.

The most popular Stem Cellar posts of 2018

/ Kevin McCormack / 2 Comments

The blog

You never know when you write something if people are going to read it. Sometimes you wonder if anyone is going to read it. So, it’s always fun, and educational, to look back at the end of the year and see which pieces got the most eyeballs.

It isn’t always the ones you think will draw the biggest audiences. Sometimes it is diseases that are considered “rare” (those affecting fewer than 200,000 people) that get the most attention.

Maybe it’s because those diseases have such a powerful online community which shares news, any news, about their condition of interest with everyone they know. Whatever the reason, we are always delighted to share encouraging news about research we are funding or encouraging research that someone else is funding.

That was certainly the case with the top two stories this year. Both were related to ALS or Lou Gehrig’s disease.  It’s a particularly nasty condition. People diagnosed with ALS have a life expectancy of just 2 to 5 years. So it’s probably not a big surprise that stories suggesting stem cells could expand that life span got a big reception.

Whatever the reason, we’re just happy to share hopeful news with everyone who comes to our blog.

And so, without further ado, here is the list of the most popular Stem Cellar Blog Posts for 2018.

All of us in the Communications team at CIRM consider it an honor and privilege to be able to work here and to meet many of the people behind these stories; the researchers and the patients and patient advocates. They are an extraordinary group of individuals who help remind us why we do this work and why it is important. We love our work and we hope you enjoy it too. We plan to be every bit as active and engaged in 2019.

Japanese scientists implant first Parkinson’s patient with replacement neurons derived from stem cells

/ Pallavi Penumetcha / Leave a comment

Parkinsons

Neurons derived from stem cells.Credit: Silvia Riccardi/SPL

Currently, more than 10 million people worldwide live with Parkinson’s disease (PD). By 2020, in the US alone, people living with Parkinson’s are expected to outnumber the cases of multiple sclerosis, muscular dystrophy and Lou Gehrig’s disease combined.

There is no cure for Parkinson’s and treatment options consist of medications that patients ultimately develop tolerance to, or surgical therapies that are expensive. Therefore, therapeutic options that offer long-lasting treatment, or even a cure, are essential for treating PD.

Luckily for patients, Jun Takahashi’s team at Kyoto University has pioneered a stem cell based therapy for PD patients.

To understand their treatment strategy, however, we first have to understand what causes this disease. Parkinson’s results from decreased numbers of neurons that produce dopamine, a molecule that helps control muscle movements. Without proper dopamine production, patients experience a wide range of movement abnormalities, including the classic tremors that are associated with PD.

The current treatment options only target the symptoms, as opposed to the root cause of the disease. Takashi’s group decided to go directly to the source and improve dopamine production in these patients by correcting the dopaminergic neuron shortage.

The scientists harvested skin cells from a healthy donor and reprogrammed them to become induced pluripotent stem cells (iPSCs), or stem cells that become any type of cell. These iPSCs were then turned into the precursors of dopamine-producing neurons and implanted into 12 brain regions known to be hotspots for dopamine production.

The procedure was carried out in October and the patient, a male in his 50s, is still healthy. If his symptoms continue to improve and he doesn’t experience any bad side effects,  he will receive a second dose of dopamine-producing stem cells. Six other patients are scheduled to receive this same treatment and Takashi hopes that, if all goes well, this type of treatment can be ready for the general public by 2023.

This treatment was first tested in monkeys, where the researchers saw that not only did the implanted stem cells improve Parkinson’s symptoms and survive in the brain for at least two years, but they also did not cause any negative side effects.

This is only the third time iPSCs have been used as a treatment option in humans. The first was for macular degeneration in 2014.

CIRM is funding a similar, albeit earlier-stage program, with Jeanne Loring at Scripps.

 

Stem Cell Agency’s Diane Winokur hailed as Visionary

/ Kevin McCormack / 2 Comments

Diane and JT

CIRM Board member Diane Winokur with CIRM Board Chair Jonathan Thomas at FFB Awards dinner

Generally speaking, I am not a huge fan of gala dinners. It’s not that I don’t like seeing people who do remarkable things getting a well-deserved honor. It’s just that the dinners often go on too long and the food is usually not very good (hey, this is San Francisco, those things matter). But last night’s Foundation Fighting Blindness Visionary Awards in San Francisco was definitely an exception to that rule.

Academy of Sciences Grand Opening

Academy of Sciences in San Francisco

Now it may be that the awards were held in the spectacular Academy of Sciences building in Golden Gate Park, or that the food was delicious. But I think the real reason is that CIRM Board member Diane Winokur was one of those being honored. The other honoree was Dr. Jacque Duncan, an amazing physician at UC San Francisco who has dedicated her life to battling diseases of the retina. The whole event was deeply emotional, and truly inspiring.

Now, Diane is a remarkable woman in many respects. She’s the Board’s Patient Advocate member for ALS (better known as Lou Gehrig’s disease) and multiple sclerosis. But Diane also considers herself a Patient Advocate for all Californians and works hard to help advance the research that could help them. She has a personal connection to vision loss as well; one of her dear friends has lost his sight because of retinitis pigmentosa, and his daughter is losing hers because of the same disease.

Diane at podiumDiane highlighted the work that CIRM is doing to help battle vision destroying diseases; how we have invested more than $125 million in 25 different projects. She talked about the encouraging news from clinical trials we are funding targeting retinitis pigmentosa and dry age-related macular degeneration. Diane said:

“These stem cell clinical trials show that progress is being made. Not as fast as we would like, but as everyone here knows, good science takes time. As a patient advocate on the CIRM Board it’s my role to represent the patient, to be their voice in making decisions about what projects to fund.

Patients are at the heart of everything we do at CIRM, from deciding on funding issues to supporting clinical trials. That’s why I feel so honored to get this award. It comes from an organization, that is equally committed to doing all it can to help people in need, to putting the patient at the center of everything they do.”

It’s clear that patients really are at the heart of the work the Foundation Fighting Blindness (FFB) does. As the organizations CEO Benjamin Yerxa said:

“We support 77 labs in the US, often funding projects no one else would. We do this because we know it is necessary to advance the field. And we are going to keep doing this as best we can, as fast as we can, for as long as we can, because we know so many people are depending on us to help them.”

The other honoree, Jacque Duncan, said after attending many previous Visionary Award dinners and seeing the people being honored it was humbling to be in that company. She talked about the exciting progress being made in the field and the people who are making it possible.

“None of this happens by chance. The path to developing new treatments takes the passion of scientists and doctors, and the commitment of patients to raising the funds needed to do this research. One gala dinner at a time, one Vision Walk at a time. All of this creates community and a common purpose. I truly believe that because of this, tomorrow will be brighter than today.”

Perhaps it’s only appropriate to leave the last word to Diane, who ended her speech saying:

“The Nobel prize winning physicist Heinrich Rohrer once said that science means constantly walking a tightrope between blind faith and curiosity; between expertise and creativity; between bias and openness; between experience and epiphany; in short, between an old today and a new tomorrow.

I believe that working together, CIRM and the Foundation Fighting Blindness, we can create that new tomorrow.”