Tuesday February 25, 2020

High Dose of Over-the-Counter Niacin Linked to Injury of Specific Cell Type in Patient’s Eye

For the study, the research team reported on a 61-year-old patient who arrived at the hospital with worsening blurry vision in both eyes

0
//
Niacin, Injury, Cell
"People who depend on vision for their livelihood need to realise there could be long-lasting consequences from inadvertent overdosing on this vitamin," Rosen said. Pixabay

Researchers have found that severe vision loss from a self-pres
cribed high dose of over-the-counter(OTC) niacin is linked to injury of a specific cell type in a patient’s eye.

Niacin, also known as vitamin B3, is used for lowering hyperlipidemia or cholesterol and comes in prescription and over-the-counter forms; it can produce a rare toxic reaction called niacin-induced cystoid maculopathy, a form of retinal swelling.

“This study shows how dangerous large doses of a commonly used over-the-counter medication can be,” said lead investigator Richard Rosen from New York Eye and Ear Infirmary (NYEE) in US.

“People who depend on vision for their livelihood need to realise there could be long-lasting consequences from inadvertent overdosing on this vitamin,” Rosen said.

Niacin, Injury, Cell
Niacin, also known as vitamin B3, is used for lowering hyperlipidemia or cholesterol and comes in prescription and over-the-counter forms; it can produce a rare toxic reaction called niacin-induced cystoid maculopathy, a form of retinal swelling. Pixabay

For the study, the research team reported on a 61-year-old patient who arrived at the hospital with worsening blurry vision in both eyes that began a month earlier.

The initial exam showed that the patient was almost legally blind, with best-corrected visual acuity of 20/150 in the right eye and 20/100 in the left eye.

The patient told doctors his medical history included significant hypertension and hyperlipidemia, but initially failed to disclose the extent of his self-prescribing.

Subsequently, he admitted to taking an extensive list of supplements, which included three to six grams of niacin daily for several months to reduce his risk of cardiovascular events and was unaware of the risk to his eyesight.

Also Read- Goa Coast in Danger with 2,800 Million Tonne Naphtha Floating Off the Coast

He purchased the supplement at a drug store after a doctor told him he had high cholesterol.

The standard dosage is one to three grams a day with a maximum dose of six grams, but doctors typically warn against treating the condition with supplements purchased over the counter and prefer to prescribe and monitor an FDA-approved dose of niacin.

NYEE clinicians diagnosed the problem using several state-of-the-art technologies, including fluorescein angiography, optical coherence tomography (OCT), and multifocal electroretinography (MERG), to examine his retina for evidence of cellular damage and monitor his response to therapy.

The imaging allowed investigators to diagnose a rare toxic reaction called niacin-induced maculopathy.

Niacin, Injury, Cell
“This study shows how dangerous large doses of a commonly used over-the-counter medication can be,” said lead investigator Richard Rosen from New York Eye and Ear Infirmary (NYEE) in US. Pixabay

The high dose of niacin led to cystoid macular edema of the retina, which is fluid in the macula (a small area in the center of the retina that produces detailed and centralised vision) that causes swelling.

The technology also allowed investigators to identify the cellular structures responsible for the patient’s condition.

The MERG recorded in this case showed reduced b-waves, which indicated that cells affected by the toxicity were the Muller cells, which span the depth of the retina like support columns.

Discontinuation of the vitamin reversed this effect and restored retinal function and electrical signals.

Also Read- Nuclear Power Corporation of India Confirmed Presence of N.Korean Malware in its System

This led investigators to demonstrate that the ‘Muller cells’ were the target of niacin toxicity, and the cause of niacin maculopathy. (IANS)

Next Story

Researchers Invent New Robotic Device To Treat Spinal Cord Injury

The test was repeated in eight directions, and the researchers used the results to compute the sitting workspace of each individual

0
Spinal cord
Spinal cord injuries (SCI) can cause devastating damage, including loss of mobility and sensation. Pixabay

 A Columbia Engineering team led by an Indian scientist has invented a robotic device that can be used to assist and train people with spinal cord injuries to sit more stably by improving their trunk control, gaining an expanded active sitting workspace without falling over or using their hands to balance.

Spinal cord injuries (SCI) can cause devastating damage, including loss of mobility and sensation.

“We designed TruST for people with SCIs who are typically wheelchair users. We found that TruST not only prevents patients from falling, but also maximises trunk movements beyond patients’ postural control, or balance limits,” said Sunil Agrawal, professor of mechanical engineering and of rehabilitation and regenerative medicine.

The study, published in the journal Spinal Cord Series and Cases, is the first to measure and define the sitting workspace of patients with spinal cord injuries based on their active trunk control with help from the “Trunk-Support Trainer (TruST)” robotic device.

The robotic trunk is a motorised-cable driven belt placed on the user’s torso to determine the postural control limits and sitting workspace area in people with spinal cord injuries.

It delivers forces on the torso when the user performs upper body movements beyond the postural stability limits while sitting.

The five patients who participated in the pilot study were examined with the Postural Star-Sitting Test, a customised postural test that required them to follow a ball with their head and move their trunk as far as possible, without using their hands.

The test was repeated in eight directions, and the researchers used the results to compute the sitting workspace of each individual.

The team then tailored the robotic device for each subject to apply personalised assistive force fields on the torso while the subjects performed the same movements again.

With the ‘TruST’, the subjects were able to reach further during the trunk excursions in all eight directions and significantly expand the sitting workspace around their bodies, on an average of about 25 per cent more.

“The capacity of ‘TruST’ to deliver continuous force-feedback personalised for the user’s postural limits opens new frontiers to implement motor learning-based paradigms to retrain functional sitting in people with SCI,” says Victor Santamaria, a physical therapist, postdoctoral researcher in Agrawal’s Robotics and Rehabilitation Laboratory.

Spinal Cord
A Columbia Engineering team led by an Indian scientist has invented a robotic device that can be used to assist and train people with spinal cord injuries to sit more stably by improving their trunk control, gaining an expanded active sitting workspace without falling over or using their hands to balance. Pixabay

Agrawal’s team is now exploring the use of TruST within a training paradigm to improve the trunk control of adults and children with spinal cord injury.

“The robotic platform will be used to train participants with the SCI by challenging them to move their trunk over a larger workspace, with the TruST providing assist-as-needed force fields to safely bring the subjects back to their neutral sitting posture,” elaborated Agrawal.

ALSO READ: Enterprise-led 5G Adoption to Make Big Mark in Addressing Food Scarcity Issues

“This force field will be adjusted to the needs of the participants over time as they improve their workspace and posture control,” he added. (IANS)