Retina

How regrowing tiny hairs could restore hearing loss

/ Kevin McCormack / 3 Comments
Man getting fitted with hearing aids

Hearing loss is something that affect tens of millions of Americans. Usually people notice those changes as they get older but the damage can be done years before that through the use of some prescription drugs or exposure to loud noise (I knew I shouldn’t have sat in the 6th row of that Led Zeppelin concert!)

Now researchers at the University of Southern California (USC) have identified the mechanism that appears to stop cells that are crucial to hearing from regenerating.

In a news release Dr. Neil Segil says this could, in theory, help reverse some hearing loss.  “Permanent hearing loss affects more than 60 percent of the population that reaches retirement age. Our study suggests new gene engineering approaches that could be used to channel some of the same regenerative capability present in embryonic inner ear cells.”

The inner ear has two types of cells that are crucial for hearing; “hair cells” are sensory receptors and these help the brain detect sounds, and support cells that play, as the name implies, an important structural and supporting role for the hair cells.

In people, once the hair cells are damaged that’s it, you can’t repair or replace them and the resulting hearing loss is permanent. But mice, in the first few days of life, have ability to turn some of their support cells into hair cells, thus repairing any damage. So Segil and the team set out to identify how mice were able to do that and see if those lessons could be applied to people.

They identified specific proteins that played a key role in turning genes on and off, regulating if and when the support cells could turn into hair cells. They found that one molecule, H3K4mel, was particularly important in activating the correct genetic changes need to turn the support cells into hair cells. But in mice, levels of H3K4mel disappeared quickly after birth, so the team found a drug that helped preserve the molecule, meaning the support cells retained the ability to turn into hair cells.

Now, obviously because this was just done in mice there’s a lot more work that needs to be done to see if it can also work in people, but Segil says it’s certainly an encouraging and intriguing start.

“Our study raises the possibility of using therapeutic drugs, gene editing, or other strategies to make epigenetic modifications that tap into the latent regenerative capacity of inner ear cells as a way to restore hearing. Similar epigenetic modifications may also prove useful in other non-regenerating tissues, such as the retina, kidney, lung, and heart.”

The study is published in the journal Developmental Cell

CIRM has funded several projects targeting hearing loss. You can find them here.

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.

Eyeing Stem Cell Therapies for Vision Loss

/ Todd Dubnicoff / 4 Comments

Back by popular demand (well, at least a handful of you demanded it!) we’re pleased to present the third installment of our Stem Cells in Your Face video series. Episodes one and two set out to explain – in a light-hearted, engaging and clear way – the latest progress in CIRM-funded stem cell research related to Lou Gehrig’s disease (Amyotrophic Lateral Sclerosis, or ALS) and sickle cell disease.

With episode three, Eyeing Stem Cell Therapies for Vision Loss, we turn our focus (pun intended) to two CIRM-funded clinical trials that are testing stem cell-based therapies for two diseases that cause severe visual impairment, retinitis pigmentosa (RP) and age-related macular degeneration (AMD).

Two Clinical Trials in Five Minutes
Explaining both the RP and AMD trials in a five-minute video was challenging. But we had an ace up our sleeve in the form of descriptive eye anatomy animations graciously produced and donated by Ben Paylor and his award-winning team at InfoShots. Inserting these motion graphics in with our scientist and patient interviews, along with the fabulous on-camera narration by my colleague Kevin McCormack, helped us cover a lot of ground in a short time. For more details about CIRM’s vision loss clinical trial portfolio, visit this blog tomorrow for an essay by my colleague Don Gibbons.

Vision Loss: A Well-Suited Target for Stem Cell Therapies
Of the wide range of unmet medical needs that CIRM is tackling, the development of stem cell-based treatments for vision loss is one of the furthest along. There are a few good reasons for that.

The eye is considered to be immune privileged, meaning the immune system is less accessible to this organ. As a result, there is less concern about immune rejection when transplanting stem cell-based therapies that did not originally come from the patient’s own cells.

The many established, non-invasive tools that can peer directly into the eye also make it an attractive target for stem cell–based treatment. Being able to continuously monitor the structure and function of the eye post-treatment will be critical for confirming the safety and effectiveness of these pioneering therapies.

Rest assured that we’ll be following these trials carefully. We eagerly await the opportunity to write future blogs and videos about encouraging results that could help the estimated seven million people in the U.S. suffering from disabling vision loss.

Related Links:

Stem Cellar archive: retinitis pigmentosa
Stem Cellar archive: macular degeneration
Video: Spotlight on Retinitis Pigmentosa
Video: Progress and Promise in Macular Degeneration
CIRM Fact Sheet on Vision Loss

Da Mayor and the clinical trial that could help save his vision

/ Kevin McCormack / 1 Comment

Former San Francisco Mayor and California State Assembly Speaker Willie Brown is many things, but shy is not one of them. A profile of him in the San Francisco Chronicle once described him as “Brash, smart, confident”. But for years Da Mayor – as he is fondly known in The City – said very little about a condition that is slowly destroying his vision. Mayor Brown has retinitis pigmentosa (RP).

RP is a degenerative disease that slowly destroys a person’s sight vision by attacking and destroying photoreceptors in the retina, the light-sensitive area at the back of the eye that is critical for vision. At a recent conference held by the Everylife Foundation for Rare Diseases, Mayor Brown gave the keynote speech and talked about his life with RP.

Willie Brown

He described how people thought he was being rude because he would walk by them on the streets and not say hello. The truth is, he couldn’t see them.

He was famous for driving fancy cars like Bentleys, Maseratis and Ferraris. When he stopped doing that, he said, “people thought I was broke because I no longer had expensive cars.” The truth is his vision was too poor for him to drive.

Despite its impact on his life RP hasn’t slowed Da Mayor down, but now there’s a new clinical trial underway that might help him, and others like him, regain some of that lost vision.

The trial is the work of Dr. Henry Klassen at the University of California, Irvine (UCI). Dr. Klassen just announced the treatment of their first four patients, giving them stem cells that hopefully will slow down or even reverse the progression of RP.

“We are delighted to be moving into the clinic after many years of bench research,” Klassen said in a news release.

The patients were each given a single injection of retinal progenitor cells. It’s hoped these cells will help protect the photoreceptors in the retina that have not yet been damaged by RP, and even revive those that have become impaired but not yet destroyed by the disease.

The trial will enroll 16 patients in this Phase 1 trial. They will all get a single injection of retinal cells into the eye most affected by the disease. After that, they’ll be followed for 12 months to make sure that the therapy is safe and to see if it has any beneficial effects on vision in the treated eye, compared to the untreated one.

In a news release Jonathan Thomas, Ph.D., J.D., Chair of the CIRM Board said it’s always exciting when a therapy moves out of the lab and into people:

“This is an important step for Dr. Klassen and his team, and hopefully an even more important one for people battling this devastating disease. Our mission at CIRM is to accelerate the development of stem cell therapies for patients with unmet medical needs, and this certainly fits that bill. That’s why we have invested almost $19 million in helping this therapy reach this point.”

RP hasn’t defeated Da Mayor. Willie Brown is still known as a sharp dresser and an even sharper political mind. His message to the people at the Everylife Foundation conference was, “never give up, keep striving, keep pushing, keep hoping.”

To learn more about the study or to enroll contact the UCI Alpha Stem Cell Clinic at 949-824-3990 or by email at stemcell@uci.edu.

And visit our website to watch a presentation about the trial (link) by Dr. Klassen and to hear brief remarks from one of his patients.