Dopamine Agonists Linked to Poorer Blood Vessel Function

Study also confirms smoking is a likely cause of blood vessel dysfunction

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Rates of blood vessel dysfunction are not significantly different in people with Parkinson’s disease compared to the general population, a small study reports.

The findings indicate that, among people with Parkinson’s, smoking and the use of treatments called dopamine agonists are associated with poorer blood vessel function.

The study, “Impairment of endothelial function in Parkinson’s disease,” was published in BMC Research Notes.

The endothelium is the membrane that surrounds the inside of blood vessels. Dysfunction of the endothelium can contribute to a number of health complications.

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It’s not clear whether there is any connection between endothelial dysfunction and Parkinson’s disease, though certain biological processes — such as dysfunction of energy-making mitochondria or overproduction of toxic molecules called reactive oxygen species — have been implicated in both.

To learn more, scientists in Slovakia assessed endothelial function in 41 people with Parkinson’s and 41 people without the disease (controls). The two groups were matched based on age, sex, and well-established vascular disease risk factors like smoking and high blood pressure.

Endothelial function was measured by calculating a parameter called reperfusion hyperemia index (RHI), which basically assesses how easily blood can flow through vessels. In accordance with prior research, RHI values less than 1.67 were considered to indicate endothelial dysfunction.

The average RHI was slightly lower in Parkinson’s patients than controls (1.8 vs. 1.9), but the difference was not statistically significant. Similarly, while  more people with Parkinson’s had endothelial dysfunction (46.3% vs. 34.1%), the difference did not reach statistical significance. That means there is a reasonable likelihood mathematically that the difference may be due to random chance.

Additional statistical models showed that, among the Parkinson’s patients, RHI values were generally lower for individuals who smoked cigarettes and those who were being treated with a dopamine agonist.

“Values of RHI in the PD group were non-significantly lower than in controls and ED [endothelial dysfunction] was non-significantly more frequent in PD patients compared to controls. In PD patients, according to linear regression analysis, smoking and the use of dopamine agonists were significant contributors in the model predicting RHI,” the scientists concluded.

The team noted that smoking is a well-established risk factor for vascular disease, but they highlighted a need for further research into the potential connection between dopamine agonists and endothelial dysfunction.

The scientists stressed this study is limited by its small size. They also noted that, while some vascular risk factors were matched between the groups, other less-understood factors may affect endothelial dysfunction in Parkinson’s patients. The researchers called for further study into the potential relationships between Parkinson’s, its treatments, and endothelial function.