Vitamin biotin eases symptoms of parkinsonism in fruit flies: Study
Biotin may protect against damage from manganese-induced parkinsonism
Biotin (vitamin B7) supplementation may offer protection against manganese-induced brain cell damage, according to a recent study.
Manganese is a naturally occurring metal that can cause manganism, a condition characterized by parkinsonism-like symptoms, such as tremors and cognitive issues.
In the study led by Souvarish Sarkar, PhD, an assistant professor at the University of Rochester Medical Center (URMC), researchers used fly models of manganese-induced parkinsonism to show that biotin supplementation may ease such symptoms.
“Biotin supplementation shows potential as a therapeutic strategy to mitigate manganese-induced neurodegeneration, and the safety and tolerability of biotin in humans make it a promising candidate,” Sarkar said in a URMC news story.
The study, “Biotin mitigates the development of manganese-induced, Parkinson’s disease-related neurotoxicity in Drosophila and human neurons,” was published in the journal Science Signaling.
Chronic exposure to manganese can lead to Parkinson’s-like symptoms
Although manganese is essential for various cellular functions, chronic exposure to elevated levels can lead to a neurodegenerative condition known as manganism. The symptoms of manganism resemble those of Parkinson’s disease and include tremor, slowed movements, stiffness, and problems with balance. They may also include hallucinations and other psychiatric symptoms common in Parkinson’s.
“However, there is a dearth of knowledge on the molecular and mechanistic levels regarding how [manganese] leads to parkinsonism,” wrote the researchers, who turned to fruit flies to replicate what happens when the body is exposed to manganese, for example, through eating contaminated fruits and vegetables.
When fed a liquid rich in manganese, adult flies had a shorter lifespan than those fed a placebo. They also had difficulties climbing and moving about. In the brain, exposure to manganese resulted in the loss of dopaminergic neurons, the nerve cells that produce the chemical signal dopamine necessary for motor control and that are gradually lost in Parkinson’s.
A detailed look into the metabolites — small molecules involved in the body’s chemical processes — revealed that manganese resulted in changes in how the flies use biotin, also known as vitamin B7. Biotin is naturally present in some foods and can be produced by bacteria in the gut. It has a key role in the production of energy.
However, biotin is also needed for the production of dopamine. Flies lacking biotinidase, an enzyme that frees biotin from proteins so it can be used, showed more severe symptoms when fed manganese compared with those with normal levels of the enzyme.
They also showed more damage to mitochondria, the structures that produce the energy needed to maintain the body’s chemical processes. These findings suggest that changes in how biotin is used may help protect against damage caused by manganese early on, before parkinsonism occurs.
Motor function improved with biotin
To test if biotin could counteract the effects of manganese, the researchers supplemented the diets of wild-type (normal) flies with biotin. As a result, the flies’ motor function improved. These findings were extended to fly models of Parkinson’s, where biotin eased motor symptoms.
In lab-grown human dopaminergic neurons, biotin protected against manganese-induced damage, improving mitochondrial function and reducing cell loss.
Analysis of brain tissue from patients with Parkinson’s revealed increased levels of biotin transporters in the substantia nigra, a region involved in motor control that is highly affected in Parkinson’s.
“Biotin-rich prebiotics or biotin-producing probiotics could provide non-pharmacological intervention options, but more studies have to performed,” Sarkar said.
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