Parkinson’s Disease (PD) is one of the most common neurodegenerative diseases in the United States, where almost 1 million patients are currently living with the disorder. PD is a progressive neurological disease caused by neuronal death in a part of the brain called the substantia nigra that affects both the physical and mental states of an individual, creating symptoms such as difficulty initiating movement, hand tremors, depression, and memory problems. While there is currently no known cure for PD, there are medications and treatments that can alleviate its symptoms. Researchers are interested in how transplanting new neurons in the brains of patients with PD may be able to treat or cure this condition in the future.
A major issue with neuron transplants from external sources is that they may not be recognized by the body’s immune system. This triggers transplant rejection, which can be life-threatening to the person receiving the neurons. Studies done in model organisms show that a way to circumvent the issue of transplant rejection is to use cells from the organism itself in the transplant. This can be done by creating induced pluripotent stem cells (iPSC), which are stem cells developed from an organism’s own cells. iPSC can be changed into various types of cells, including neurons, which can then be transplanted back into the organism without the risk of transplant rejection, a process known as an autologous transplant. A transplant made of cells taken from a different organism is called an allogeneic transplant. Though new technologies are making autologous transplants increasingly viable, allogeneic transplants have traditionally been the standard option for transplant patients.
Embed from Getty Images
Researchers grew neurons from pluripotent stem cells, which they transplanted into primates with Parkinson’s Disease.
Image Source: Science Photo Library – STEVE GSCHMEISSNER.
Scientists at the University of Wisconsin-Madison created neurons from the iPSCs of primates with PD. They performed autologous transplants on half of their study subjects and allogeneic transplants on the other half. The researchers then compared the primates’ PD symptoms before and after the transplant and also imaged their brains using positron emission tomography (PET) to monitor the status of the transplants. The researchers found that the primates who received autologous transplants experienced a decrease in PD symptom severity and an increase in mobility. Additionally, the primate brain scans also showed that the autologous transplant neurons were able to grow and form new connections in the brain, indicating that the transplanted material had successfully integrated into the animal’s brain, while the allogeneic transplant neurons did not show such growth. The results of this study indicate that autologous transplants of neurons may be a promising direction of research for PD treatment. Perhaps someday, neuron transplants may prevent our loved ones from suffering as much from this disorder.
Featured Image Source: Giovanni Cancemi
