Neurodegenerative Diseases: Parkinson’s Disease

Written by: Caroline Kim

September 21, 2024

In our last section on our neurodegenerative diseases, we’ll dive into a rather well known condition: Parkinson’s disease. This is the second most common neurodegenerative disease, affecting approximately 1 million people in the U.S. and 10 million people globally (Parkinsongs.org). This progressive disease causes deterioration in neurons, affecting daily life as symptoms worsen.

Primary symptoms of Parkinson’s as noted by the National Institute of Neurological Disorders and Stroke, include tremors, muscle stiffness, bradykinesia, and postural instability. Other relevant symptoms and conditions include mental health problems, difficulty swallowing/chewing, speech changes, bladder/bowel problems, difficulty sleeping, cognitive problems, orthostatic hypotension, and fatigue (National Institute of Health. “Parkinson’s Disease.”). Some of these terms are less obvious; bradykinesia is described by the NINDS as “... a slowing down of spontaneous and some automatic movement”. Another one of these symptoms, orthostatic hypotension, is essentially a “sudden drop in blood pressure when a person stands up from a lying down or seated position” (National Institute of Health. “Parkinson’s Disease.”). 

The exact cause for Parkinson’s is unknown, but relevant factors include genetics and environmental factors; exposure to certain toxins and pesticides can increase one’s risk of developing Parkinson’s (Mayo Clinic Staff). Those of older age (50+) and males have a higher risk of developing this condition (Mayo Clinic Staff). Diagnosis of Parkinson’s involves evaluation of medical history, lab/diagnostic tests, and blood tests, CT scans, genetic testing, MRI’s, PET scans, spinal taps, and skin biopsies (Cleveland Clinic Medical Professional). While there is no cure for this disease, as is the case with many other neurodegenerative conditions, treatments exist. Treatment often entails medications or sometimes even device implants for deep brain stimulation (Cleveland Clinic Medical Professional). According to Cleveland Clinic, experimental treatments such as stem cell transplants, neuron-repair treatments, and gene therapies are also implemented. 

Now we can take a closer look at how Parkinson’s affects the brain. While this condition affects various parts of the brain, the region known as the substantia nigra, which produces dopamine and controls purposeful movement; according to the NINDS, studies have shown that individuals with parkinsons have a loss of 60-80% of the dopamine producing cells in this region. Another significant brain impact is that “People with PD also lose the nerve endings that produce the neurotransmitter norepinephrine—the main chemical messenger to the part of the nervous system that controls many automatic functions of the body, such as pulse and blood pressure” (National Institute of Health. “Parkinson’s Disease.”). Other changes in the brain involve lewy bodies and mitochondrial changes. According to Mayo Clinic, clumps of protein, known as lewy bodies, are heavily associated with Parkinson’s; in addition, the alpha-synuclein found within these lewy bodies form in clumps which cells can not break down. 

Sources:

1. Parkinsongs.org. “Statistics.” Parkinson’s Foundation, www.parkinson.org/understanding-parkinsons/statistics. Accessed 21 Sept. 2024. 

2. National Institute of Health. “Parkinson’s Disease.” National Institute of Neurological Disorders and Stroke, U.S. Department of Health and Human Services, 4 Sept. 2024, www.ninds.nih.gov/health-information/disorders/parkinsons-disease. Accessed 21 Sept. 2024. 

3. Mayo Clinic Staff. “Parkinson’s Disease.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 5 Apr. 2024, www.mayoclinic.org/diseases-conditions/parkinsons-disease/symptoms-causes/syc-20376055. Accessed 21 Sept. 2024. 

4. Cleveland Clinic Medical Professional. “Parkinson’s Disease: What It Is, Causes, Symptoms & Treatment.” Cleveland Clinic, 30 Aug. 2024, my.clevelandclinic.org/health/diseases/8525-parkinsons-disease-an-overview. Accessed 21 Sept. 2024.