Tag Archives: sigh

Doctors restore patient’s sight with stem cells, offering new hope for cure to blindness

Scientists have developed a specially engineered retinal patch to treat people with sudden, severe sight loss.

The macula lutea (an oval region at the center of the retina) is responsible for the central, high-resolution color vision that is possible in good light; when this kind of vision is impaired due to damage to the macula, the condition is called age-related macular degeneration (AMD or ARMD). Macula lutea means ‘yellow spot’ in Latin.

Picture of the back of the eye showing intermediate age-related macular degeneration.
Via Wikipedia

Douglas Waters, an 86-year-old from London, had lost his vision in July 2015 due to severe AMD. After a few months, Waters became part of a clinical trial developed by UC Santa Barbara researchers that used stem cell-derived ocular cells. He received his retinal implant at Moorfields Eye Hospital, a National Health Service (NHS) facility in London, England.

Before the surgery, Water’s sight was very poor, and he wasn’t able to see anything with his right eye. After the surgery, his vision improved so much that he could read the newspaper and help his wife in the garden.

The study, published in Nature Biotechnology, shows groundbreaking results. Researchers could safely and effective implant a specially engineered patch of retinal pigment epithelium cells derived from stem cells to treat people with sudden severe sight loss from wet AMD. This is the first time a completely engineered tissue has been successfully transplanted in this manner.

“This study represents real progress in regenerative medicine and opens the door on new treatment options for people with age-related macular degeneration,” said co-author Peter Coffey, a professor at UCSB’s Neuroscience Research Institute and co-director of the campus’s Center for Stem Cell Biology & Engineering.

Douglas Waters was struggling to see up close after developing severe macular degeneration, but 12 months on he is able to read a newspaper again

AMD usually affects people over the age of 50 and accounts for almost 50% of all visual impairment in the developed world. The condition disturbs central vision responsible for reading, leaving the surrounding eyesight normal. Wet AMD is caused by hemorrhage or liquid accumulation into the region of the macula, in the center of the retina. Wet AMD almost always starts as dry AMD. Researchers believe that this new technique will be the future cure for dry AMD.

Scientists wanted to see whether the diseased retinal cells could be replenished using the stem cell patch. They used a specially engineered surgical tool to insert the patch under the affected retina. The operation lasted almost two hours.

Besides Water, another patient, a 60-year-old woman who also suffered from wet AMD, underwent the surgery. The two patients were observed for one year and reported improvements to their vision. The results were incredible — the patients went from being almost blind to reading 60 to 80 words per minute with normal reading glasses.

“We hope this will lead to an affordable ‘off-the-shelf’ therapy that could be made available to NHS patients within the next five years,” said Coffey, who founded the London Project to Cure Blindness more than a decade ago.

 

 

sighing

This is how the brain makes you sigh every 5 minutes

Sighing is a fundamental biological reflex that’s a lot more important than most people care to think. We don’t just sigh when we’re in a position of weariness or relief, but quite regularly for no particular reason — about 12 times an hour. Sighing opens up the lungs, and is thus  vital to life. Now, researchers say they’ve found the neural pathways thatgovern the reflex. Those who suffer from breathing problems as well as compulsive sighers will benefit the most from the findings.

sighing

When we sigh, the million of tiny sacks inside the lungs called the alveoli inflate causing oxygen to enter and carbon dioxide to leave. Sometimes these sacks collapse and it takes a sigh to open them which is typically two breaths in for one breath out. If we didn’t sigh, we’d be dead in under an hour.

Joining forces, researchers from labs at  UCLA and Stanford sought to unravel the neural mechanism that leads to sighing. The researchers screen some 19,000 mouse genes that are involved in brain cells. They singled out 200 neurons in the brain stem that produce  one of two neuropeptides — small protein-like molecules (peptides) used by neurons to communicate with each other — but couldn’t tell at this point which were involved in sighing.

Later they found some peptides triggered a second set of 200 neurons, some of whom were already involved in controlling breathing. A handful of neurons were found to activate the mouse’s breathing muscles to produce a sigh — roughly 40 times an hour. When one of the peptides was blocked, the sighing rate was cut in half. Silencing both peptides halted sighing completely, the researchers reported in Nature.

“Sighing appears to be regulated by the fewest number of neurons we have seen linked to a fundamental human behavior,” explained Jack Feldman, a professor of neurobiology at the David Geffen School of Medicine at UCLA and a member of the UCLA Brain Research Institute. “One of the holy grails in neuroscience is figuring out how the brain controls behavior. Our finding gives us insights into mechanisms that may underlie much more complex behaviors.”

“Unlike a pacemaker that regulates only how fast we breathe, the brain’s breathing center also controls the type of breath we take,” Mark Krasnow, a professor of biochemistry and Howard Hughes Medical Institute Investigator at the Stanford University School of Medicine said. “It’s made up of small numbers of different kinds of neurons. Each functions like a button that turns on a different type of breath. One button programs regular breaths, another sighs, and the others could be for yawns, sniffs, coughs and maybe even laughs and cries.”

Drugs could be designed that target these peptides to either suppress or enhance their generation on a case by case basis. For instance, there are anxiety disorders and other psychiatric conditions where sighing grows debilitating. Conversely, in some cases poor breathing is caused by a poor sighing reflex. As for conscious sighing triggered by emotional states, this is still a subject for debate among scientists.

“There is certainly a component of sighing that relates to an emotional state. When you are stressed, for example, you sigh more,” Feldman said. “It may be that neurons in the brain areas that process emotion are triggering the release of the sigh neuropeptides — but we don’t know that.”