People who have had kidney, heart, lung, or bone-marrow transplants are less likely to develop Parkinson’s disease than the general population, research suggests.
Chronic neuroinflammation is a hallmark of Parkinson’s disease with studies suggesting that inflammatory processes contribute to disease risk and progression, although such biological response is unlikely to be the primary cause of neuronal death. That is why researchers suspect that reducing inflammation in the brain has the potential to slow neurodegeneration.
Anti-rejection drugs, also known as immunosuppressant medications, inhibit the immune system’s activity and reduce overall inflammation in the body, including the central nervous system.
Patients who undergo organ transplants usually are given these types of medicines to lower their body’s ability to reject the transplanted organ.
“Because inflammation may play a role in the pathophysiology of PD [Parkinson’s disease], it is possible that immunosuppressants could reduce the risk” of the disease, researchers wrote.
A team led by Washington University School of Medicine in St. Louis researchers investigated the risk of Parkinson’s disease in relation to tissue transplant. This same team had shown previously that individuals taking selected immunosuppressants had a lower risk of Parkinson’s disease than the general population Medicare beneficiaries who were studied.
In the most recent study they assessed Medicare beneficiaries (age 66–90 years) data from 2004 to 2009 and identified 89,790 Parkinson’s disease cases. For the control group, researchers selected a 0.5% random sample of all Medicare beneficiaries included in the study period, totaling 118,095 subjects.
History of kidney, heart, lung, bone-marrow, pancreas or cornea transplant was then registered. There were 278 transplants in the Parkinson’s sample and 302 in the control group.
Statistical analysis revealed patients who underwent transplants had a 37% lower risk of developing Parkinson’s than the general Medicare population.
“Overall, patients who had undergone tissue transplant more than five years prior to PD [Parkinson’s disease] diagnosis or reference had lower risk of PD,” researchers wrote.
This correlation was consistent for kidney, heart, lung, and bone-marrow transplants. Liver or corneal (the transparent layer that makes up the front of the eye) transplant was not linked to Parkinson’s disease risk.
When adjusting for underlying cause of the transplants, such as valvular heart disease, diabetes with renal complications, or chronic hepatitis infection, organ transplant remained inversely correlated with Parkinson’s risk. However, the association with kidney transplant became statistically non-significant.
“This study provides evidence that tissue transplant may be associated with a lower PD [Parkinson’s disease] risk, warranting further investigation to identify factors that mediate this relationship, including a potential effect of immunosuppressive therapy on PD risk,” researchers concluded.