Hair metal patterns differ in people with Parkinson’s, new study suggests
Lower iron was the most consistent change across people and mice
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- Parkinson’s patients show altered hair metal patterns, notably lower iron levels.
- Mouse studies suggest this lower iron may be linked to gut absorption and bacteria changes.
- Gut dysfunction and microbiota changes may play a role in Parkinson’s iron imbalance.
People with Parkinson’s disease have altered levels of certain metals, including iron, in their hair, according to a new study.
Experiments in a mouse model suggest these iron changes may be linked to intestinal changes consistent with a reduced capacity to absorb iron, along with increases in gut bacteria genes involved in iron uptake.
According to the researchers, these findings suggest that digestive system changes and shifts in gut bacteria may play a role in altered iron levels in people with Parkinson’s.
The study, “Hair metal dysregulation in Parkinson’s disease: implications for diagnosis and Gut-Brain axis involvement,” was published in iScience.
Hair metal analysis offers clues about Parkinson’s-related changes
Hair metal isn’t just a subgenre of rock ‘n’ roll that gained popularity in the ’70s and early ’80s — human hair actually contains tiny amounts of metals such as iron, lead, and zinc. Because these metals circulate in the bloodstream, small amounts can become incorporated into growing hair. As such, analyzing metals in hair can offer insight into long-term metal exposure in the body.
Previous studies have suggested that levels of certain metals are altered in people with Parkinson’s and may be linked to disease symptoms, but the reasons for these differences are not fully understood.
In this study, scientists in China measured hair metal levels in 60 people with Parkinson’s disease and 60 people without the condition. They found that people with Parkinson’s tended to have lower levels of iron and copper, but higher levels of manganese and arsenic. Using a statistical model that combined these four metals, the researchers found they could correctly identify about 73% of Parkinson’s cases and about 91% of those without the disease.
The researchers also noted that people with Parkinson’s reported eating animal offal and shellfish more often, foods that can accumulate arsenic, which may be one possible contributor to higher arsenic levels observed in this group. However, they cautioned these findings do not establish cause and effect, and further studies are needed to better understand how diet and metal exposure may relate to Parkinson’s disease.
The scientists then conducted additional experiments in a mouse model to better understand the biological mechanisms behind these metal changes. In this model, Parkinson’s-like disease was triggered using a chemical that damages brain cells, allowing researchers to examine how the disease affects metal levels in hair.
Mouse study suggests gut changes may affect iron levels
The researchers found that these mice had reduced iron levels in their hair, consistent with the human findings. Copper and manganese did not show differences in the mouse model, while zinc levels were slightly higher. Because the decrease in iron was the most consistent finding across both humans and mice, the researchers focused on understanding how Parkinson’s-like disease may affect iron levels.
“The most consistent finding was a significant reduction in iron levels, observed in both human subjects and animal models, underscoring systemic iron deficiency as a robust cross-species feature associated with [Parkinson’s]-like pathology [disease biology],” the researchers wrote.
Results suggested the Parkinson’s mice had intestinal changes consistent with a reduced capacity to absorb iron from food. At the same time, gut bacteria in these mice showed increased abundance of genes involved in iron uptake. Together, these findings may help explain why iron levels were lower in the animals’ hair.
“Taking all these results together, we suggest that the drop of iron levels in the hair could be associated with the gastrointestinal dysfunction in [Parkinson’s] patients, as shown in many other studies, and also the imbalance of the gut microbiota, which exhibited enhanced iron uptake capacity,” the scientists concluded. They noted, however, that these data don’t prove a cause-and-effect relationship, highlighting a need for further studies into how iron metabolism is impacted in Parkinson’s.
