Sunday November 17, 2019

Researchers Find Cells Linked to Blindness in Elderly People

This study helps pinpoint cell types that can be investigated closely to develop new types of therapeutics

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Bindness
Age-related macular degeneration is one of the leading causes of Blindness in the elderly. Pixabay

A team of researchers have discovered cells that lead to progressive loss of central vision among the elderly.

Age-related macular degeneration is one of the leading causes of blindness in the elderly.

Genome-wide studies have identified almost three dozen genes that play a role in the disease, but exactly where in the eye they inflict damage was not well known.

Researchers from Yale University, the Broad Institute of the Massachusetts Institute of Technology, and Harvard University reported in the journal Nature Communications that glial cells (or support cells), and vasculature cells tasked with providing blood to the retina as well as cone cells contribute to degeneration of the macula, in the central part of the retina.

“This study helps pinpoint cell types that can be investigated closely to develop new types of therapeutics,” said Brian Hafler, assistant professor of ophthalmology and visual science and of pathology at Yale.

There are a limited number of effective long-term treatments available for the two forms of macular degeneration.

The wet form is caused by growth of abnormal blood vessels underneath the macula, which can be mitigated by regular injections in the eye.

Blindness
While genes associated with the risk of developing macular degeneration had been identified, the team used new single-cell sequencing to generate the first comprehensive human retinal atlas and employed data analysis technology to localize their effects to specific cell types associated with Blindness. Pixabay

Other than eye vitamin supplements, there is no treatment for the dry form of the disease, which is marked by accumulations of yellow deposits called drusen in the macula.

While current treatments provide some benefits, over time there can be a continued, progressive loss of vision in both forms of the disease.

While genes associated with the risk of developing macular degeneration had been identified, the team used new single-cell sequencing to generate the first comprehensive human retinal atlas and employed data analysis technology to localize their effects to specific cell types associated with the disease.

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While they found risk genes associated with cones, the cell type key to central vision, the researchers also found an association with glial and vascular cells — providing possible targets for novel therapies to improve and restore vision. (IANS)

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Immune Cells Become Active and Repair Brain While Sleep: Study

For the findings, researchers conducted the study on mice

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Sleep
Study suggests that the enhanced remodeling of neural circuits and repair of lesions during Sleep may be mediated in part by the ability of microglia to dynamically interact with the Brain. Pixabay

Researchers have found that immune cells called microglia, which play an important role in reorganising the connections between nerve cells, fighting infections, and repairing damage, are also primarily active while we sleep.

Microglia serve as the brain’s first responders, patrolling the brain and spinal cord and springing into action to stamp out infections or gobble up debris from dead cell tissue.

“This research shows that the signals in our brain that modulate the sleep and awake state also act as a switch that turns the immune system off and on,” said study lead author Ania Majewska, Professor at University of Rochester in the US.

In previous studies, Majewska’s lab has shown how microglia interact with synapses, the juncture where the axons of one neuron connects and communicates with its neighbours.

The microglia help maintain the health and function of the synapses and prune connections between nerve cells when they are no longer necessary for brain function.

For the findings, researchers conducted the study on mice.

The current study points to the role of norepinephrine, a neurotransmitter that signals arousal and stress in the central nervous system.

This chemical is present in low levels in the brain while we sleep, but when production ramps up it arouses our nerve cells, causing us to wake up and become alert.

The study showed that norepinephrine also acts on a specific receptor, the beta2 adrenergic receptor, which is expressed at high levels in microglia.

When this chemical is present in the brain, the microglia slip into a sort of hibernation.

Sleep
Researchers have found that immune cells called microglia, which play an important role in reorganising the connections between nerve cells, fighting infections, and repairing damage, are also primarily active while we Sleep and affects Brain. Pixabay

The study, which employed an advanced imaging technology that allows researchers to observe activity in the living brain, showed that when mice were exposed to high levels of norepinephrine, the microglia became inactive and were unable to respond to local injuries and pulled back from their role in rewiring brain networks.

“This work suggests that the enhanced remodeling of neural circuits and repair of lesions during sleep may be mediated in part by the ability of microglia to dynamically interact with the brain,” said study first author Rianne Stowell.

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“Altogether, this research also shows that microglia are exquisitely sensitive to signals that modulate brain function and that microglial dynamics and functions are modulated by the behavioural state of the animal,” Stowell said.

The study was published in the journal Nature Neuroscience. (IANS)