Scientists search for that defining “Aha!” moment – and MSU professor David Kaufman’s came about as a result of his commitment to understanding a degenerative disease as well as accepting both the ordinary and unorthodox throughout his career. David Kaufman is the chair of neurology at Michigan State University’s College of Human Medicine.
Early symptoms of multiple sclerosis and how they are 10 years later – optic neuritis
This image shows myelin (blue) in the optic nerve of a normal mouse (top), a mouse with optic neuritis (middle), and an optic neuritis mouse treated with ST266 (bottom) .Ken Shindler, MD, PhD, Perelman School of Medicine, University of Pennsylvania
A new therapeutic agent tested in a mouse model of multiple sclerosis (MS) produced anti-inflammatory activity and prevented loss of cells in the optic nerve, according to a new study by researchers in the Perelman School of Medicine at the University of Pennsylvania, with Pittsburgh-based Noveome Biotherapeutics. The research was conducted in the laboratory of Kenneth Shindler, MD, PhD, an associate professor of Ophthalmology and Neurology, and published in Scientific Reports.
The team demonstrated the therapeutic potential of the agent, called ST266, for treating optic neuritis, inflammation that damages the optic nerve and is a common presenting feature of MS. About half of patients diagnosed with MS experience optic neuritis, which can cause mild to moderate permanent loss of vision, but rarely complete blindness. ST266 is a solution of molecules that stimulate paracrine signaling. This is one way in which cells “talk” to each other: One cell produces a chemical signal that induces changes in nearby cells.
“In this case, the idea is that the many factors in ST266 not only bind to cell receptors and cause changes within the cells they bind to, but those cells then alter their own secretions and provide additional signals to other neighboring cells, thus propagating an effect from a relatively small amount of protein present in the therapy itself,” Shindler said. “To the best of our knowledge, this study demonstrates, for the first time, the ability to treat the optic nerve via the intranasal route of administration.”
When ST266 was given to the MS mice via their nose, it reached the central nervous system within 30 minutes and was detected at higher concentrations in parts of the eye and optic nerve compared to other areas of the brain. These findings demonstrated that this type of delivery can target tissues of the eye, which is easier, less painful, and less invasive than injecting medication directly into the eye.
In mice with optic neuritis, the team showed that early treatment with ST266 prevented damage and dysfunction, marked by significantly reduced loss of optic nerve cells, and suppression of inflammatory cell infiltration into the optic nerve. This in turn was associated with limitation of the degree of demyelination caused by MS- related optic neuritis. However, “it’s not known if these effects are independent effects of the therapy or interdependent effects,” Shindler said.
Treatment of later-stage optic neuritis in the MS mice showed similar results, resulting in improved visual function compared to untreated groups. The data suggest that ST266 helps promote optic neuron survival by potentially activating multiple pathways, including those that prevent cell death.
“These results are particularly important as the preservation of retinal cells is a significant factor when treating optic neuritis,” Shindler said. “There is an increased need for combination treatment options that are able to prevent nerve-cell axon loss for patients with optic neuritis.”
Currently, the only acute treatment for MS-related optic neuritis is IV steroids, which only hasten whatever amount of visual recovery will occur even without treatment. Steroids do not prevent nerve damage or permanent vision loss. “ST266’s ability to preserve vision in the preclinical model and reduce neuronal loss would be a huge advance if it translates to human patients,” Shindler said.
The study also has implications beyond MS-related optic problems. “We also showed an effect on cultured neurons, suggesting that effects may translate to other optic nerve diseases, as well as other brain neurodegenerative diseases,” Shindler said.
UC Riverside-led mouse study stresses MS treatment should be started early
Maria Sekyi (left), the first author of the research paper, is seen here with Seema Tiwari-Woodruff, the study’s lead author, in a photo dated Sept. 13, 2019. CREDIT Tiwari-Woodruff lab, UC Riverside.
A team led by a biomedical scientist at the University of California, Riverside, reports a drug — an estrogen receptor ligand called indazole chloride (IndCl) — has the potential to improve vision in patients with multiple sclerosis, or MS.
The study, performed on mice induced with a model of MS and the first to investigate IndCl’s effect on the pathology and function of the complete afferent visual pathway, is published in Brain Pathology. The afferent visual pathway includes the eyes, optic nerve, and all brain structures responsible for receiving, transmitting, and processing visual information.
In MS, a disease in which the immune system “demyelinates” or eats away at the protective covering of nerves, the initial period of inflammation and demyelination often damages the optic nerve and other parts of the visual system first. As a result, approximately 50% of patients with MS experience optic neuritis — inflammatory demyelination of the optic nerve — prior to showing initial symptoms. Almost all MS patients have impaired vision at some point during disease progression. Symptoms can include eye pain, blurred vision, and progressive vision loss that can lead to blindness, among other visual impairments.
The optic nerve, a heavily myelinated bundle of nerves located at the back of the eye, transfers visual information from the retina to the vision centers of the brain through electrical impulses. Myelin acts as an insulating substance that speeds the transmission of these electrical impulses. Partial myelin loss slows transmission of visual information; severe myelin loss may stop the signal altogether.
The researchers used IndCl to assess its impact on demyelinating visual pathway axons. The treatment induced remyelination and mitigated some damage to the axons that resulted in partial functional improvement in vision.
“IndCl has been previously shown in mice to reduce motor disability, increase myelination, and neuroprotection in the spinal cord and corpus callosum,” said Seema Tiwari-Woodruff, a professor of biomedical sciences at the UC Riverside School of Medicine and the study’s lead author. “Its effects in the visual system, however, were not evaluated until now. Our study shows the optic nerve and optic tract, which undergo significant inflammation, demyelination, and axonal damage, are able to restore some function with IndCl treatment with successful attenuation in inflammation and an increase in remyelination.”
The visual pathway in mice is similar to that in humans. The mouse brain is, therefore, an excellent model for scientists to study vision impairment. In the lab, Tiwari-Woodruff and her research group first induced the mouse model of MS. They let the disease progress for about 60 days and when the disease reached a peak between 15 and 21 days, they administered IndCl to half the mice. At the end of the experiment, they performed functional assay to measure the visual electrical signal; and immunohistochemistry to examine the visual pathway. The mice that received the drug showed improvement in myelination, with visual function improving by about 50%.
For Tiwari-Woodruff, the next question is how IndCl treatment induces functional remyelination in the visual pathway. Her lab, in collaboration with the lab of co-author John A. Katzenellenbogen at the University of Illinois at Urbana-Champaign, is investigating new drugs that are analogues of IndCl.
“Measuring visual function and recovery in the presence of novel therapies can be used to screen more effective therapies that will protect axons, stimulate axon remyelination, and prevent ongoing axon damage,” Tiwari-Woodruff said.
Currently approved MS drugs reduce inflammation but do not prevent neurodegeneration or initiate remyelination. Further, they only partially prevent the onset of permanent disability in patients with MS.
“We treated the MS mice with IndCl at peak disease,” Tiwari-Woodruff said. “If the brain is highly diseased, some of the axons that could potentially restore visual function are too damaged and will not recover. There’s a point of no return. Our paper stresses that to acquire vision improvement, treatment must start early. Early treatment can recover 75%-80% of the original function.”
Tiwari-Woodruff stressed that although additional studies are required, the new findings show the dynamics of visual pathway dysfunction and disability in MS mice, along with the importance of early treatment to mitigate axon damage.
“There is a strong and urgent need to find a therapeutic candidate that restores neurological function in patients with MS,” Tiwari-Woodruff said. “Therapeutics must target remyelination and prevent further axonal degeneration and neuronal loss. The good estrogens, which ha
Start watching to learn about optic neuritis