Breaking News
September 24, 2018 - EPA Plan Will Maintain Carbon Emissions From Power Plants
September 24, 2018 - Characterizing pig hippocampus could improve translational neuroscience
September 24, 2018 - Element3 Health reports social and mental engagement play key role in overall health
September 24, 2018 - Paralympic medalists support Fight for Sight’s unique virtual event
September 24, 2018 - ADCETRIS drug receives approval in Japan as frontline treatment option for Hodgkin lymphoma
September 24, 2018 - Public awareness of urological conditions found to be alarmingly low across Europe
September 24, 2018 - Fitter Folks Suffer Milder Strokes: Study
September 24, 2018 - Novel botulinum toxin compound relieves chronic pain
September 24, 2018 - CHMP recommends approval of Gilenya for treatment of multiple sclerosis in children, adolescents
September 24, 2018 - National Friendly’s private medical insurance is a hit with women living in the South East
September 24, 2018 - Academics receive prestigious awards for achievements in blood pressure research
September 24, 2018 - Obese pregnant women can restrict weight gain safely with proper nutrition guidance
September 24, 2018 - CHMP adopts positive opinion of Takeda’s ALUNBRIG for treatment of ALK+ non-small cell lung cancer
September 24, 2018 - China NMPA approves LENVIMA for treatment of unresectable hepatocellular carcinoma
September 24, 2018 - A new approach for finding Alzheimer’s treatments
September 24, 2018 - USC research uncovers previously unknown genetic risk factor for dementia
September 24, 2018 - Study examining mental health among students finds significant disparities in treatment across race
September 24, 2018 - Breakthrough discovery paves way for future test to identify drowsy drivers
September 24, 2018 - Transcatheter mitral-valve repair in patients with heart failure
September 24, 2018 - Study opens new avenues for treatment of Laing distal myopathy
September 24, 2018 - Stroke Facts | cdc.gov
September 24, 2018 - Sarcolipin tricks muscle cells into using more energy, burning fat
September 24, 2018 - Enrollment in opioid controlled substance agreement reduces primary care visits
September 24, 2018 - UTA researchers patent new smart seat cushion technology that helps prevent painful ulcers
September 24, 2018 - Second HPV-Related Primary Cancers Common in Survivors
September 24, 2018 - How a virus destabilizes the genome
September 24, 2018 - Old letters provide insight into Spanish flu pandemic horror
September 23, 2018 - Smart textile-based soft robotic exosuit helps wearers save energy and traverse difficult terrain
September 23, 2018 - New research hub to drive radical change in development and manufacturing of vaccines
September 23, 2018 - AHA: For Hispanics, Neighborhood May Be Key Factor in Heart Disease Risk
September 23, 2018 - Excessive airway nerves tied to more severe asthma symptoms, study finds
September 23, 2018 - Study highlights need to remain vigilant in maintaining key infection control processes
September 23, 2018 - Novel therapeutic strategy for blood vessel related disorders, such as cancer and retinopathy
September 23, 2018 - New naturally occurring antibiotic found effective against Mycobacterium tuberculosis
September 23, 2018 - First-in-human phase 0 study shows clinically-relevant activity of new drug in glioblastoma
September 23, 2018 - Removing tobacco product display from shops reduced number of children buying cigarettes
September 23, 2018 - Random fraction of specialized immune cells leads the charge in battling invaders
September 23, 2018 - Few minutes of sprinting exercise may be as effective as longer exercise sessions
September 23, 2018 - Researchers use neutrons to make first direct observations of water in lipid bilayers
September 23, 2018 - Researchers demonstrate pre-clinical success for universal flu vaccine in new paper
September 23, 2018 - Study reveals surprising gaps in some HIV medical providers’ knowledge of ACA
September 23, 2018 - Oxehealth secures European medical device accreditation for vital signs measurement software
September 23, 2018 - HTN Tx Intensification Common Upon Discharge in U.S. Vets
September 23, 2018 - Fibre can strengthen the intestinal barrier
September 23, 2018 - New platform examines infectious pathogens that may spread from animals to humans
September 23, 2018 - Demographers create detailed color map of population aging in Europe
September 23, 2018 - New type of fatty acid can slow down overreactive immune system
September 23, 2018 - Innovative procedure could provide breakthrough in treating early-stage lung cancer
September 23, 2018 - Research finds drop in number of measles cases in the EU/EEA since March 2018
September 23, 2018 - Researchers acquire new insights into DNA polymerases
September 23, 2018 - Alzheimer’s diagnosis might become simpler with new brain imaging method
September 23, 2018 - Reports Warn of Growing Opioid Crisis Among Seniors
September 23, 2018 - Researchers unravel why people with HIV suffer from more neurologic diseases
September 23, 2018 - Human brain structured to make best possible decision with limited resources
September 23, 2018 - KHN’s ‘What the Health?’ Health on the hill
September 23, 2018 - Bad air and inadequate data prove an unhealthy mix
September 23, 2018 - Regular bedtime and wake time important for heart, metabolic health even among adults
September 23, 2018 - HIV and a tale of a few cities
September 23, 2018 - NIH launches clinical trial to test infusions of combination antibodies in people with HIV
September 23, 2018 - Researchers develop new system to detect consumption of synthetic cannabinoids
September 23, 2018 - Vax-Hub to influenze radical change in development and manufacturing of vaccines
September 23, 2018 - People who have slept lesser than seven hours have higher risks of car crashes
September 23, 2018 - an ancient art may work best to prevent falls in old age
September 23, 2018 - Consumption of foods with lower nutritional quality related to increased cancer risk
September 23, 2018 - Patient Health Information Often Shared Electronically
September 23, 2018 - Can machine learning bring more humanity to health care?
September 23, 2018 - Body organs undergo structural changes in response to diet
September 23, 2018 - Genetic polymorphisms linked with muscle injury and stiffness
September 23, 2018 - As states try to rein in drug spending, feds slap down one bold Medicaid move
September 22, 2018 - Why Eczema Is Tougher to Treat for Black Patients
September 22, 2018 - Team reveals that human genome could contain up to 20 percent fewer genes
September 22, 2018 - USC research uncovers previously unknown genetic risk factor for Alzheimer’s disease
September 22, 2018 - Novel method achieves accurate and precise temperature estimation in fat-containing tissues
September 22, 2018 - BSI accredits Oxehealth’s vital signs measurement software as Class IIa medical device
September 22, 2018 - Evolution of psychiatric disorders and human personality traits
September 22, 2018 - Obesity in early puberty doubles asthma risk for boy’s future offspring
September 22, 2018 - World’s most advanced real-time patient monitoring platform receives key US patent
September 22, 2018 - Study explores connection between sexuality and cognitive status in older adults
September 22, 2018 - LSTM partners with TB Alliance to develop novel TB drug regimens
September 22, 2018 - Annual wellness visits improve delivery of preventive services in elderly population
Immune cells can repopulate in the retina after elimination, mice study shows

Immune cells can repopulate in the retina after elimination, mice study shows

image_pdfDownload PDFimage_print

Immune cells called microglia can completely repopulate themselves in the retina after being nearly eliminated, according to a new study in mice from scientists at the National Eye Institute (NEI). The cells also re-establish their normal organization and function. The findings point to potential therapies for controlling inflammation and slowing progression of rare retinal diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD), the most common cause of blindness among Americans 50 and older. A report on the study was published online today in Science Advances. The NEI is part of the National Institutes of Health.

“Neuroinflammation is an important driver of the death of neurons in retinal diseases,” said Wai T. Wong, M.D., Ph.D., chief of the NEI Section on Neuron-Glia Interactions in Retinal Disease, and the study’s lead investigator. “Our study is foundational for understanding ways to control the immune system in the retina.” Control of the immune system is important for developing new treatments for a variety of eye conditions, including AMD, RP, or for certain types of retinal injury.

The retina is a thin layer of cells in the back of the eye that includes light-sensing photoreceptor cells and other neurons involved in transmitting visual information to the brain. Mixed in with these cells are microglia, specialized immune cells that help maintain the health of the retina and the function of retinal neurons. Microglia are also present in other parts of the central nervous system, including the brain. In a healthy retina, communication between neurons and microglia is important for maintaining the neuron’s ability to send signals to the brain. When the retina is injured, however, microglia have an additional role: They migrate quickly to the injury site to remove unhealthy or dying cells. However, they can also remove healthy cells, contributing to vision loss. Studies show that in degenerative retinal disorders like AMD and RP, inhibiting or removing microglia can help retain photoreceptors, and thus slow vision loss. But return of microglia is still important to support the retina’s neurons.

Wong and colleagues were interested in understanding what happens in the retina after microglia have been eliminated, particularly whether the cells could return to their normal arrangement and fulfill their normal functions. To test this, they depleted the microglia in the retinas of mice using the drug PLX5622 (Plexxikon), which blocks the microglial CSF-1 receptor. Microglia depend on continuous signals through this receptor for survival. Interruption of this signaling for several days caused the microglia to nearly disappear, leaving just a few cells clustered around the optic nerve-;the cable-like bundle of nerve fibers that carries signals from the retina to the brain-;in the mouse retinas. Since loss of microglia for a short time doesn’t affect the function of neurons, removing microglia temporarily-;in order to reduce inflammation for example-;could potentially be useful as a therapeutic intervention for degenerative or inflammatory disorders of the retina.

“If we were to get rid of the microglia while a large, inappropriate immune response was happening,” said Wong, “we might be able to miss the worst of the inflammation, but still come back into balance at a later point in time. We could hit pause on the immune system in the retina in a directed way.”

Within 30 days after stopping the drug, Wong and colleagues found that the microglia had repopulated the retina, returning to normal density after 150 days. Using a novel method for visually tracking microglial movements in the retina, they determined that the returning microglia initially grew in clusters near where the optic nerve leaves the eye. Gradually, new microglia expanded outwards towards the edges of the retina. Over time, the cells re-established an even distribution across and through the various layers of the retina.

“The organization of these immune cells is quite elaborate, and all the organization comes right back,” Wong said. “We can actually image the eye and watch these cells divide and split and migrate as part of the repopulation response.”

To test whether the new microglia were fully functional, the researchers used an injury model where photoreceptor cells are damaged by bright light. The new microglia were able to activate and migrate to the injury site normally. In addition, using electroretinography (ERG), a technique that measures the electrical signals generated by retinal neurons after being stimulated with light, the researchers tested the health of different groups of neurons. They found that the microglia were able to communicate with and fully maintain the function of neurons in the retina, especially when the depletion was short-lived.

Drugs that remove microglia are now administered systemically, affecting the brain and other parts of the central nervous system. More research is needed to find ways to administer these drugs directly to the retina, sparing off-target tissues.

Source:

https://nei.nih.gov/content/immune-cells-retina-can-spontaneously-regenerate

Tagged with:

About author

Related Articles