Anyone who has ever watched a friend or loved one succumb to the slow degradation of Parkinson’s disease will understand the urge to cure it. Read on to learn more about how stem cells could be a possible treatment option for Parkinson’s disease.
In this article:
- What Causes Parkinson’s Disease?
- How Do Stem Cells Work?
- What Stem Cells Did Scientists Use to Accomplish This?
- What Are the Challenges of Using Stem Cells to Cure Parkinson’s?
- What Are the Benefits?
Parkinson’s Disease Treatment | Could Stem Cells Be The Answer?
With Parkinson’s disease, the slow erosion of control, tremors, and muscular immobility cause a heartbreaking loss of movement and independence. For obvious reasons, Parkinson’s disease has attracted substantial attention across medical and scientific communities.
Thankfully, there is hope that scientists may be on track to develop a potential treatment. Researchers from Japan’s Kyoto University used stem cells to repair nerve cells in the brains of monkeys, proving that neuron functionality – once thought gone forever when lost – may prove reparable.
By July 2018, the university had announced it would launch a physician-lead study utilizing stem cells in human patients.
Specifically, Kyoto University and its University Hospital and Center for iPS Cell Research and Application (CiRA) are moving forward with the world’s first clinical study for Parkinson’s disease. The treatment to be tested will use brain cells derived from a type of stem cell called an induced pluripotent stem cell (iPS cell).
iPS cells are a type of non-controversial stem cell that can be created from mature adult cells, such as blood or skin cells.
Parkinson’s Disease Clinical Trial
In preparation for the trial, the Japanese researchers are using blood cells from healthy donors to create iPS cells. These cells are then being turned into dopaminergic progenitors, cells which will be transplanted into the brains of seven patients with Parkinson’s disease.
Blood cells –> iPS cells –> Dopaminergic progenitors
The objective of the study will be to determine the safety and efficacy of transplanting these manipulated cells into the brains of living humans. Paperwork for the trial was submitted to Japan’s Pharmaceutical and Medical Devices Agency (PMDA) on June 4, 2018, and has been approved to proceed.
Patients interested to participate in the trial must meet three criteria:
- Live in Japan
- Have Japanese public health insurance
- Understand the Japanese informed consent form
Despite the breakthrough, the challenge remains a significant one. To understand the role stem cells may have in Parkinson’s disease treatment options, it is critical to understand what causes the disease, as well as how stem cells work and the reasons they offer a potent tool in the war against this and other neurological disorders.
What Causes Parkinson’s Disease?
Parkinson’s disease, explains the Parkinson’s Foundation, is a degenerative disorder of the nervous system. It is rooted in a loss of dopamine-producing neurons, which results in lower than normal levels. Without this neurotransmitter, neurons are less able to send signals to other nerve cells, which is critical for motor function, speech, and other behaviors.
Up until now, the scientific community has regarded nerve cells as a non-renewable resource. Like many other types of tissue in the body, such as heart or cartilage tissues, humans are born with a set number of such cells. Generally speaking, once they’re gone, they’re gone.
However, the intersection between stem cell activity and Parkinson’s disease is a potentially rich one. Stem cells may prove able to reverse Parkinson’s disease by repairing what was once thought to be irreplaceable: neurons.
How Do Stem Cells Work?
When a single sperm fertilizes a single egg, a miracle occurs. The combination of the two, called a zygote, has the requisite 46 chromosomes required to build a human body. However, given that it is only one cell, the zygote does not have the building blocks that we commonly associated with human life, such as muscles, organs, skin, and so forth.
What happens then? The singled cell zygote becomes a multi-cellular embryo that contains totipotent stem cells. These powerful cells can become all of the cells of the human body, as well as the cells of the embryo and developing fetus. As embryonic development progresses, the cells become pluripotent, meaning they can grow into any tissue in the human body, but no longer remain as versatile as the earlier totipotent cells.
Shortly thereafter, fetal development creates multipotent stem cells, which can become any tissue within a class of tissues (for instance, a blood stem cell can become dozens of specialized blood cells).
Induced pluripotent stem cells (iPS cells) also exist, which are stem cells created by using laboratory manipulation to “reverse engineer” mature cells into an embryonic stem cell (ESC) like state. Commonly derived from skin or blood cells, iPS cells have many of the benefits of embryonic stem cells, without the controversy.
Stem cells, in other words, have the power to replace cells that ordinarily would have disappeared for good.
What Stem Cells Did Scientists Use to Accomplish This?
Multiple different types of stem cells have shown promise in the cure of many types of disease and injury. Embryonic stem cells, because they can transform into any cell in the entire body, have long held a coveted status in the stem cell field. However, the moral outcry that has in past accompanied their use – as well as their relative scarcity compared to adult cells – have led scientists to look for other options.
Among the most promising of those options are induced pluripotent stem cells, also called iPS cells. As described above, these cells were once normal tissue-specific cells – commonly skin or blood cells – that researchers coaxed back into a stem cell-like state, making them capable of transforming into any human body cell.
Because an effective Parkinson’s disease treatment would need to restore dopamine-producing neurons to a healthy (pre-diseased) state, the question is, will the researchers from Kyoto University succeed at doing this for the first time in history?
What Are the Challenges of Using Stem Cells to Cure Parkinson’s?
As described by The Cure Parkinson’s Trust, using stem cells is not as easy as simply inserting them into the brain and telling them “Get to work!” Because pluripotent stem cells have the ability to develop into so many different types of tissue, that means they also have the inclination.
As Agnete Kirkeby, a researcher at Lund University, explains, these stem cells want to run in all different directions, like a class of Kindergartners. The scientist’s role is to ensure they all run in the same direction.
Another challenge is the fact that the study cited above was performed on monkeys, making it pre-clinical research. Before this treatment can reach wider audiences, it must show positive therapeutic effects in the seven human patients enrolled to be treated by Kyoto University and its affiliated hospital.
What Are the Benefits?
One of the biggest benefits of pluripotent stem cells, and specifically for the iPS cells being explored for their role in treating Parkinson’s, is that they have the capacity to divide indefinitely.
That’s the other limitation of tissue-specific cells, which rely on mitotic division to reproduce. They have only so many divisions in them before they break down and start exhibiting genetic code errors or dying off.
In contrast, iPS cells can divide forever, maintaining the same fidelity to the genetic code and providing the same benefits. Therefore, even if Parkinson’s symptoms from nerve die-off do occur, stem cells already in the body can step back in and fix the problem once more.
Interested in more about stem cells and Parkinson’s disease?
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