Parkinson’s Disease | What is Parkinson’s Disease?

Originally posted on September 13, 2022 @ 10:11 am

One of the top research organizations examining how the environment may affect Parkinson’s disease is NIEHS. The institute closely collaborates with other NIH research programmes as well as partners and scientists from all over the nation to examine every facet of this disease.

What is Parkinson’s Disease?

After Alzheimer’s disease, Parkinson’s disease is the second most prevalent neurodegenerative condition.
The brain or spinal cord and the nerves in your body communicate information that influences your muscles and organs. Your nerves are not functioning normally if you have neurodegeneration. Parkinson’s disease is an ongoing, progressive movement disorder

How Many People Affected by Parkinson’s Disease

Due to the lack of a national registry, it is difficult to estimate the exact number of people who have Parkinson’s disease. The disease, however, is thought to affect close to 1 million Americans. About 60 years old is the typical onset age. A study shows that the number of people who have it goes from about 1% at age 60 to 4% at age 80.
Parkinson’s affects people of all racial backgrounds, ethnicities, nationalities, and socioeconomic status. Celebrities with the illness include civil rights activist Jesse Jackson, actors Michael J. Fox and Alan Alda, singer Linda Ronstadt, and actors Michael J. Fox and Alan Aldan.
Parkinson's disease
Parkinson’s disease

What are the  Signs and Symptoms of Parkinson’s Disease?

Some typical motor symptoms are:
  • Shaky or tremors in the hands, arms, legs, jaw, and face.
  • Rigidity or stiffness of the trunk and limbs
  • Movement that is slow
  • Balance, speech, and motor coordination issues
Additionally, there are non-motor symptoms that may appear years before the onset of motor issues. These symptoms include:
  • Constipation
  • impairment of the mind.
  • Depression
  • Fatigue
  • low level of odor
  • Recurrent dreaming disorder (dream-enacting behavior)
Tremors, a loss of grip strength, and changes in gait are just a few of the warning signs of disease that usually develop gradually and get worse over time. Symptoms can vary, as can how they develop. Although there is no known cure for Parkinson’s disease, medications and treatments can help manage symptoms.

What Are The Causes Of Parkinson’s Disease?

Parkinson’s disease has an elusive exact cause. A late-onset form of Parkinson’s that lacks a clear genetic cause affects the majority of patients with the condition. In between 2% and 10% of cases, Parkinson’s disease develops before the age of 50. This condition might have a genetic basis.
Parkinson’s disease most likely results from interactions between environmental and genetic factors. For a full understanding of Parkinson’s risk, it is important to study both genetic and environmental factors together.
  • Environmental toxins might stress and harm cells, resulting in brainstem inflammation.
  • As a result of these exposures, the brain may age more quickly. Mitochondria are the parts of cells that produce energy.
  • A misfolded protein called alpha-synuclein is toxic to nerve cells and is one of the main signs of Parkinson’s disease. Toxicant exposure may cause a lot of alpha-synuclein to build up in the body.
  • Less dopamine is present in Parkinson’s patients.
  • Dopamine levels are lower in Parkinson’s sufferers.
According to studies, when 50% or more of the dopamine neurons in the midbrain are gone, symptoms of Parkinson’s disease typically start to manifest. As tiny groups of neurons in the centre of the brain die, the brain advances slowly. Dopamine, which transmits signals to areas of the brain that coordinate muscular movement, is reduced as a result of the slow death of these neurons. Dopamine is responsible for this message transmission.
Decades of research show that the loss of nerve cells seen in Parkinson’s disease may be caused by a number of molecular processes.
Though some experts believe it may begin in the gut, Parkinson’s disease kills brain nerve cells. People with Parkinson’s disease have abnormal aggregates of misfolded alpha-synuclein proteins in their intestines. A chain reaction that travels all the way up the valgus nerve, which is directly connected to the brain, may be set off by these clumps, which may lead to neighboring proteins misfolding and clumping as well.
Research funding that contributes to a better understanding of Parkinson’s disease is desperately needed. Finding environmental factors linked to the start of Parkinson’s could lead to new ways to prevent and treat the disease.

What is the NIEHS up to?

Parkinson's disease
Parkinson’s disease
Finding out what might cause or aid in the prevention of Parkinson’s disease requires interdisciplinary study, which NIEHS supports. Because no one can foresee which lines of inquiry will result in significant discoveries, a variety of approaches is essential. We’ll keep making progress in our understanding of Parkinson’s thanks to basic research. The following highlights from NIEHS research are organised by environmental factors that may affect Parkinson’s and by study methodologies.


Two employees are applying insecticide to a field during harvest.
There is growing evidence from both human and animal research that exposure to some pesticides can raise a person’s risk of getting Parkinson’s disease.
The onset and progression of Parkinson’s disease may be influenced by a number of pesticides, including paraquat, maneb, ziram, benomyl, and several organophosphate pesticides, such as diazinon and chlorpyrifos,
  • According to a 17-year NIEHS-funded study of the connections between Parkinson’s disease, the environment, and genes.
  • In accordance with an additional NIEHS study, those who regularly used the pesticides rotenone or paraquat were 2.5 times more likely to acquire Parkinson’s disease than nonusers.
  • Parkinson’s disease may also be more likely to occur in those who are exposed to pesticides in their house or yard.
  • Pesticides may obstruct biological pathways that typically defend dopaminergic neurons, the brain cells that the disease preferentially targets. 3
  • The structures in mitochondria, which produce the energy needed by cells to function, can be directly inhibited by some pesticides, such as rotenone. Researchers at the NIEHS demonstrated in mice that rotenone exposure early in development disrupted mitochondria and altered the epigenome, or the chemical tags that control genes, in ways that remained throughout life.
  • Free radicals can harm cells, and other pesticides like paraquat have been proven to boost their production.
  • Some people are more likely to get sick from pesticides than others because of their age or their genes.
Several research projects have found differences in genes that explain why some people seem to be more likely to get Parkinson’s disease.
  • According to research using data from the NIEHS-conducted Agricultural Health Study, Parkinson’s risk from paraquat use was shown to be especially high in those with a specific version of the GSTT1.5 gene.
  • The PON1 gene, which is crucial for the metabolism of organophosphate pesticides, has also been linked to previous studies showing that the disease progresses more quickly in people with lower amounts of the gene.

Research into the connections between avoidable exposures and Parkinson’s disease is still being done, and preventative treatments may also be developed to help lower the disease’s prevalence. Farmers who use paraquat, permethrin, and trifluralin, for example, had a lower chance of getting Parkinson’s disease if they wore protective gloves and followed other hygiene rules.

Trichloroethylene (TCE)

TCE is a chemical ingredient found in several domestic cleaning products, dry cleaning, and industrial degreasers. When it gets out of factories and into the environment, it can pollute the air, water, and soil.
Based on substantial evidence of carcinogenicity from research in humans, the National Toxicology Program indicates that TCE is known to be a human carcinogen. It has been connected to blood, liver, and kidney malignancies.
The protein kinase LRRK2, which is active in the brain and other bodily tissues, may be affected by TCE exposure and increase the risk of Parkinson’s disease, according to a study supported by the NIEHS.

Brain injuries

The loss of dopaminergic neurons as a result of head trauma has been linked in numerous studies to Parkinson’s disease. People with genetic risk factors for alpha-synuclein disease and those who have been exposed to pesticides like paraquat may be particularly affected by head injuries. 9 People with head injuries who reside in or work close to areas where paraquat has been used have a higher risk of developing Parkinson’s disease.

Air Pollution

Air pollution consists of hazardous substances that have both natural and man-made origins. Although the detrimental effects of air pollution on the heart and lungs are widely recognised, their impacts on the brain are less clear. According to recent research, air pollution may have an impact on the biological processes connected to Parkinson’s disease. One study, for example, discovered that early childhood exposure to high levels of air pollution caused neuroinflammation, a changed brain immunological response, and the accumulation of toxic alpha-synuclein deposits.10
A study conducted by NIEHS experts and their associates showed only weak evidence of a link between air quality and the risk of Parkinson’s disease. However, the study found that smoking status and gender did matter. According to the research, female nonsmokers who were exposed to high levels of air pollution caused by particulate matter had a higher risk of contracting the disease. The study suggests that more research be done to find out how air pollution makes this population more vulnerable.1

Diet and lifestyle.

The man is grinning for the camera while holding a coffee cup.
Parkinson’s disease development and progression may be influenced by dietary and lifestyle choices. Understanding the role that these things may play in the disease may change how we try to prevent and treat it in the future.
Caffeine: Caffeine may lessen the likelihood of getting the illness. A separate study found that Parkinson’s patients who had drank coffee their entire lives had a slower progression of the disease, less cognitive decline, and a lower mortality rate.13 Animal studies have also demonstrated that caffeine can protect the brain’s dopaminergic neurons. The NIEHS researchers examined data from a large sample of older Americans and discovered that higher caffeine intake was associated with a lower risk of Parkinson’s in both men and women.
Meat cooking: When meat is cooked at a high temperature, compounds called heterocyclic amines (HCAs) are created. Although their impact on neurological illnesses has received less attention, these chemicals have been studied for their involvement in cancer. The NIEHS grantees used animal models to demonstrate that a number of HCAs were specifically harmful to the dopaminergic neurons impacted by Parkinson’s disease. The findings are significant since HCAs are a dietary component that is frequently ingested.
Vitamin D: Numerous studies indicate that vitamin D insufficiency may contribute to the onset of Parkinson’s disease15. Vitamin D, which can be absorbed from food or sunlight, is crucial for maintaining healthy brain function as well as strong muscles and good balance.
Researchers at the UCLA School of Public Health supported by the NIEHS discovered that genetic variations that impact the body’s response to vitamin D may affect a person’s susceptibility to cognitive loss in Parkinson’s disease. More research is required to fully understand this connection. 16
Exercise: Regular exercise can affect many chronic conditions, such as cancer and cardiovascular disease, and it can enhance a person’s quality of life. Numerous studies imply that these advantages could also serve as a defense against Parkinson’s disease.
In older U.S. adults, increased levels of moderate to vigorous physical activity in middle age were linked to a lower risk of developing Parkinson’s disease.17 Exercise may also be beneficial for those who already have the condition, as it can improve balance and reduce depressive symptoms.
For instance, some research indicates that practicing tai chi helps patients with mild to moderate Parkinson’s disease balance better and prevent falls. A recent study found that people with Parkinson’s disease lost their motor skills and mental abilities more slowly if they had played competitive sports in the past and worked out more often throughout their lives.18
Workplace Exposure to Heavy Metals: Heavy metal manganese exposure can cause signs of Parkinson’s disease, such as tremors in the arms and hands, difficulty speaking, and a lack of facial expression among welders. Even when manganese levels are below the legal limit, these symptoms may get worse as workers are exposed to it more often.19 NIEHS grantees found out how manganese exposure can cause toxic clusters of the protein alpha-synuclein to build up and spread.20 This study gives more information about the biological mechanisms that link manganese exposure to Parkinson’s-like symptoms.
Disease Prediction: Some of the premotor symptoms and risk factors that may be connected to Parkinson’s
a few of the premotor symptoms and risk factors that may be connected to Parkinson’s.
Years before some muscular issues manifest, Parkinson’s disease premotor symptoms may appear.
Researchers may be able to comprehend the causes of the disease and its progression by considering Parkinson’s as a systemic sickness that takes decades to manifest. Premotor symptoms, such as constipation, olfactory loss, exhaustion, and mood or anxiety disorders, are some of the early warning signs.
A mathematical algorithm created by NIEHS-funded researchers could alert doctors to patients who may need to be checked for Parkinson’s disease early on. The predictive model uses demographic information as well as medical tests and diagnoses found in Medicare claims data to pinpoint people who have a high chance of developing the condition. Using this method to figure out other things, like environmental risks, can help find out if the disease is more or less likely.
Other research by NIEHS-funded researchers discovered a chemical signature, or biomarker, in the blood that foretells the quick development of the disease’s motor symptoms.22 The researchers also discovered biomarkers that indicate the immune systems of Parkinson’s disease patients age more quickly. The discoveries mark a significant advancement in our knowledge of the illness’s progressive evolution.

Knowledge of Disease Progression

Parkinson's disease
 Parkinson’s disease
Learning what causes the selective loss of dopamine neurons may help inform the development of new treatments that slow or reverse disease progression. In the past few decades, animal models have been developed and used to gain valuable insight into the signs and progression of Parkinson’s disease.2
Other scientists are testing what different chemicals in the brain might do and learning more about how neurodegeneration shows up in worms and zebrafish.
Brain imaging techniques and genome-wide association studies help figure out more about how Parkinson’s disease is caused at the molecular level.
Research at NIEHS is supported by grants.
In addition to the research results described above, NIEHS is financing more than 45 grant projects linked to Parkinson’s disease.
The institute’s Revolutionizing Innovative: Visionary Environmental Health Research (RIVER) initiative is one way it promotes Parkinson’s research. This Programme offers long-term funding for researchers pursuing difficult but possibly ground-breaking scientific areas.
As an illustration, Kim Tieu, Ph.D., o f the Steeple: College of Public Health and Social Work in Miami, Florida, is looking into environmental variables that may cause the death of brain cells in Parkinson’s disease in 2019. One objective is to create medicines that stop their loss. Tieu’s research will look at how manganese and pesticides cause harmful proteins in the brain to build up and spread.
NIEHS Internal Research
At NIEHS, teams of well-known scientists from different fields work in our labs to figure out how the environment, genes, and interactions between genes and the environment affect Parkinson’s disease.
The Ion Channel Physiology Group studies the Cys-loop ligand-gated ion channel superfamily, with a focus on the nicotinic acetylcholine receptor channels and how they work in neurological diseases.
As a way to slow the progression of the disease, the Neuropharmacology Group is working on a number of studies to explain the pathophysiological mechanisms behind Parkinson’s disease and to create innovative therapeutic drugs that specifically target these mechanisms.

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