Why Organ Transplant Patients May Be at Lower Risk for Alzheimer's Disease

Why Organ Transplant Patients May Be at Lower Risk for Alzheimer's Disease
Why Organ Transplant Patients May Be at Lower Risk for Alzheimer's Disease

A treatment taken by organ transplant patients to prevent organ rejection may help protect against Alzheimer's disease, according to a new study from The University of Texas Medical Branch (UTBM) at Galveston. The findings are scheduled for publication in an upcoming issue of the Journal of Alzheimer's Disease.

Previous studies have shown that calcineurin, an enzyme that regulates communication between brain cells and memory function, plays a central role in the harmful effects of the Aβ oligomers, toxic protein aggregates that target and disrupt the point of communication between brain cells. Using a mouse model, the researchers showed that blocking calcineurin restored memory function; however, treatment with calcineurin-blocking agents may be challenging in people since the drug suppresses the immune system.

In order to bypass this issue, the researchers analyzed data from the medical records of 2,644 patients who received organ transplants and were taking calcineurin inhibitor-based medications, such as tacrolimus or cyclosporine. Because memory impairment can limit compliance among these patients, any evidence of impairment is noted as part of the medical care for transplant recipients.

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The participants were separated into groups by age at the time of last visit or death, gender and ethnicity. Eight participants showed evidence of dementia - two were younger than 65 years of age, five were 65–74 years of age, and one was in the 75–84 years of age group.The UTMB study data was compared with national data obtained from the 2014 Alzheimer's Association Facts and Figures dataset on age-matched patients to compare the prevalence of Alzheimer's. When compared to the national data from the general population, the prevalence of dementia in the transplant group was significantly lower (patients >65 years of age: 11% vs. 1.02%; patients >75 years of age: 15.3% vs. 0.6%, respectively). The researchers got similar results when they compared their over 65 years of age group with the prevalence of Alzheimer's in the general population of the state.

"Taken together, our findings from these people confirm the data obtained with animal models and support, for the first time in human subjects, our notion that calcineurin inhibition has a protective effect on the development and possible progression and even reversal of Alzheimer's disease," said senior author Giulio Taglialatela, Professor and Vice Chair for Research in the department of neurology and director of UTMB's Mitchell Center for Neurodegenerative Diseases. "Therefore, we are currently working on devising treatment strategies to obtain the same beneficial effects in AD humans using low doses of calcineurin inhibitors that result in minimal or no immunosuppression, thus limiting possible undesired side effects."

For more information visit UTMB.edu.

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