This article needs to be updated.(January 2024) |
The research in Parkinson's disease (also known as clinical trials, medical research, research studies, or clinical studies) refers to any study intended to help answer questions about etiology, diagnostic approaches or new treatments of Parkinson's disease (PD) by studying their effects on human subjects. Clinical trials are designed and conducted by scientists and medical experts, who invite participants to undergo testing new vaccines, therapies, or treatments. [1]
Only a small fraction of patients with Parkinson's disease participate in clinical research and specially in clinical trials. When clinical trials lack participation, it causes a significant delay in the development of new drugs and treatments. [2]
One of the purposes of clinical research is to test the safety and efficacy of new treatments. Clinical research may also be conducted to learn other things about medical treatments or procedures, such as how to make an earlier diagnosis or how the treatment interacts with other drugs.
Though there are many types of clinical research, the two most common are interventional and observational. For example, researchers trying to identify causes of PD may conduct an observational study to examine genetic or environmental factors that may have triggered the disease in an individual. Natural history studies that evaluate how Parkinson's affects different people and how it changes over time are another example of observational research. Diagnostic accuracy studies are used to investigate how well a test, or a series of tests, are able to correctly identify diseased patients.
Researchers conducting clinical trials test the impact of treatments. These can include changing behavior, taking medications, or performing surgery. Interventional and observational research are equally important in helping to answer questions, develop new treatments, and ultimately find a cure for Parkinson's. Clinical trials are conducted in a series of phases.
Among the interventional and observational studies for Parkinson's disease, research is ongoing in a number of specific areas.
Quality of life research investigates the function that physical therapy, occupational therapy, exercise or other interventions may play in the quality of life of persons with Parkinson's disease. Persons with Parkinson's disease may experience motor symptoms (tremors, rigidity, slowness of movement, postural instability and gait dysfunctions) [3] as well as non-motor symptoms (neuropsychiatric symptoms, autonomic dysfunction, or other; see Parkinson's disease). [4] Due to this diversity of symptoms, Parkinson's disease may impact upon an individual's physical, social and mental well-being. For example, difficulties with movement can lead to difficulties with self-care, embarrassment, social-isolation, and depression. [5]
Research may investigate whether there is a relationship between quality of life and a symptom of Parkinson's disease. Research on Parkinson's disease has investigated the link between quality of life and axial rigidity, [6] personality traits, [7] and patient education. [8]
Alternatively, a study may evaluate the effectiveness of an intervention on the mitigation of symptoms, and the subsequent impact on quality of life. For example, an ongoing clinical study exploring Vitamin D as a possible therapy to improve balance and decrease the risk of falling in people with Parkinson's [9] expects a subsequent increase in safety and well-being. Another recent study used data mining and analysis from previous clinical research to explore improvement in motor function people with Parkinson's disease experience after treatment with levodopa. [10] The study concluded that motor learning in the presence of levodopa may improve the body's ability to adapt to Parkinson's disease. [11]
Quality of life measures are increasingly being incorporated into clinical trials, therefore much research has gone into validating quality of life measures for persons with Parkinson's disease. [3]
Neuroprotection is treatment that may slow down, stop, or reverse the progression of Parkinson's. Researchers are attempting to develop neuroprotective agents for Parkinson's disease, as well as other neurodegenerative brain disorders.
Several molecules have been proposed as potential neuroprotective treatments. [12] However, none of them has been conclusively demonstrated to reduce degeneration in clinical trials. [12] Agents currently under investigation as neuroprotective agents include anti-apoptotic drugs (omigapil, CEP-1347), antiglutamatergic agents, monoamine oxidase inhibitors (selegiline, rasagiline), promitochondrial drugs (coenzyme Q10, creatine), calcium channel blockers (isradipine) and growth factors (GDNF). [12]
Researchers are also investigating vaccines for Parkinson's disease that produce cells that change the way the body's immune system responds to the loss of dopamine. This treatment has shown success in reversing Parkinson's in mice, and researchers are investigating the viability of clinical studies in people. [13]
Exercise may be neuroprotective. Animal studies show exercise may protect against dopaminergic neurotoxins, and research conducted via prospective studies shows the risk of Parkinson's disease in humans is reduced significantly by midlife exercise. [14] More research is needed to investigate the benefits of exercise in the early stage of Parkinson's, the most suitable type of exercise, when exercise should be implemented, and the optimal duration of exercises. [15]
A 2009 review of 11 systematic reviews and 230 random controlled trials, showed the effectiveness of Chinese Herbal Medicine (CHM) as a paratherapy for Parkinson's disease patients. [16]
Of those people with PD, it is only a small percentage that inherits the disease. However, the study of genetic forms of Parkinson's can assist scientists in learning more about the non-inherited forms. Several current studies are examining the genetic factors of Parkinson's disease. [17] An example of genetic research is a recent study that investigated the GBA gene as a suspected cause of early-onset Parkinson's. [18]
A genetic study involving researchers from BGI Genomics reveals the genetic cause of Parkinson's disease. [19] The study, published in Neuroscience Bulletin, discovered that a mutation in the Cysteinyl-tRNA synthetase (CARS) gene (c.2384A>T; p.Glu795Val; E795V) is responsible, offering a new path for prevention and control of the disease.
Advances in surgical procedures and neuroimaging techniques have ensured that surgical approaches can be as effective as medication at relieving some PD symptoms. Deep brain stimulation (DBS) is a surgical technique whereby a tiny electrode is inserted deep in the brain. The electrode is connected to a battery pack that implanted under the collarbone via a subcutaneous wire. DBS is effective in suppressing symptoms of PD, especially tremor. [17] A recent clinical study led to recommendations on identifying which Parkinson's patients are most likely to benefit from DBS. [20]
In an animal model, manipulating glial precursor cells produced astrocytes that repaired Parkinson's multiple types of neurological damage. The researchers implanted cells only in rats with disease signs. The astrocytes used in the study differ from other types of astrocytes present in the mature brain. When implanted into the brains of rats with the disease, the new cells acted similar to astrocytes in the developing brain, which are more effective at building connections between nerves. The implanted astrocytes restored health and stability and allowed the nerve cells to resume normal activity. [21]
Successful long-term therapy must both protect the areas of the brain under attack and foster the repair of dopaminergic neurons damage to other brain cell populations. Astrocyte dysfunction can contribute to multiple neurological disorders. [21]
After transplantation, dopaminergic, interneurons and synaptophysin were all rescued. Interneurons play an important role in information processing and movement control and are lost in Parkinson's. Synaptophysin is a protein that is essential for communication between nerve cells. The transplanted rats recovered motor skills to normal levels, essentially reversing all symptoms. No previous therapies rescued these cells. [21]
Parkinson's clinical research studies need volunteers at all stages of the disease to help solve the unanswered questions about Parkinson's and to develop new treatments. Some studies seek to enroll specific groups of people. [22]
A number of Parkinson's disease clinical research studies seek to enroll people newly diagnosed with PD that are not currently undergoing any treatment. These trials vary in scope, some focusing on neuroprotection in which researchers seek to determine whether a certain compound might offer protection to dopamine-producing cells, thus helping to slow or stop the progression of the disease. [23]
In addition to patients with PD, healthy controls, including friends and family members of those with Parkinson's, are also needed for clinical trials. Family members may participate in genetic studies, and healthy people can participate in trials that require a control group of participants without PD. Control groups are necessary as a means of testing the research being studied. [24]
People with PD, their friends, and their family members all have many reasons to consider participating in clinical research. Many participants believe that their involvement benefits themselves and the future of other people with the disease. Without clinical research participants, many of the advances in treating PD would not have happened. In addition to furthering the scientific community's knowledge of Parkinson's, clinical trial participation may offer access to leading healthcare professionals and potentially useful new drugs and therapies. This care is often provided free of charge in exchange for participation in the study. Finally, by participating in clinical studies, those whose lives are impacted by PD may increase knowledge and understanding of the disease. [25]
It can be a challenge to find the right clinical trial, and it can be even more challenging for the trial team members to find volunteers. People with PD may consult their doctors, discuss with their family members, and speak to other clinical trials participants about their experiences. [26] Online resources for participation can be found at www.FoxTrialFinder.org. and www.ClinicalTrials.gov.
People with Parkinson's disease who are considering participating in clinical research have resources available to help them navigate the clinical research process.
Led by The Michael J. Fox Foundation for Parkinson's Research, the Fox Trial Finder is a matching site that connects clinical trials to potential volunteers. [27] Since its launch in 2012, the Fox Trial Finder has registered more than 19,000 volunteers across multiple continents. Volunteers enter their information—from location to the medicines they take—into a profile on Fox Trial Finder, which then matches them to nearby trials seeking volunteers with their particular criteria. The Fox Trial Finder seeks volunteers both with and without Parkinson's disease.
The Parkinson's Disease Foundation's Parkinson's Advocates in Research (PAIR) program is a patient-based initiative that ensures people with Parkinson's disease have a role in shaping the clinical research process. By training advocates with Parkinson's disease to serve as patient representatives on clinical research advisory boards, the PAIR program aims to improve outcomes by helping researchers overcome and identify barriers in research that they may otherwise overlook. [28] Participants in the PAIR program receive training through PDF's Clinical Research Learning Institute, an annual multi-day training that focuses on education via training sessions, clinical researcher led workshops, as well as interaction with study coordinators and representatives from both the government and the industry. [29] [ non-primary source needed ]
The NINDS Parkinson's Disease Biomarkers Program brings together various stakeholders to create a resource of longitudinal biofluid samples from PD patients and controls and their associated clinical assessment data for biomarker discovery research. Neuroimaging and genomic data are also available for some of the samples. All samples are stored at the NINDS Human Genetics Repository at Coriell Institute and can be requested through the PDBP Data Management Resource.
The National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health (NIH), is a major funder of Parkinson's disease research in the US. In 2012, the NINDS funded approximately $98 million out of a total of $154 million in NIH-supported PD research. The NINDS supports basic, translational, and clinical PD research programs through a variety of mechanisms, including the Morris K. Udall Centers of Excellence for Parkinson's Disease Research and the Parkinson's Disease Biomarkers Program (PDBP). NINDS has just completed a major planning effort to determine priorities for future Parkinson's disease research.
The Parkinson's Disease Foundation is a leading national presence in the United States in Parkinson's disease research, education and public advocacy. PDF works on behalf of people who live with Parkinson's disease by funding promising clinical research to find treatments and cures for Parkinson's. [30] PDF was founded in 1957, and since then has invested more than $115 million on scientific research. [31]
The Michael J. Fox Foundation aims to develop a cure for Parkinson's disease. As the largest private foundation for Parkinson's disease in the US, the Michael J. Fox Foundation has spent 325 million dollars on research. [32] In 2010, the Fox foundation launched the first large-scale clinical study on evolution biomarkers of the disease with a cost of 40 million dollars in 5 years. [33]
The CRC for Mental Health [34] is an Australian Federal Government funded research consortium researching biomarkers, imaging reagents and therapeutics for early diagnosis of Parkinson's Disease. [35]
The Cure Parkinson's Trust, set up in the UK in 1968 by Tom Isaacs, [36] was instrumental in arranging a ground-breaking clinical trial of the drug GDNF at the University of Bristol during the 2010s.
Huntington's disease (HD), also known as Huntington's chorea, is an incurable neurodegenerative disease that is mostly inherited. The earliest symptoms are often subtle problems with mood or mental/psychiatric abilities. A general lack of coordination and an unsteady gait often follow. It is also a basal ganglia disease causing a hyperkinetic movement disorder known as chorea. As the disease advances, uncoordinated, involuntary body movements of chorea become more apparent. Physical abilities gradually worsen until coordinated movement becomes difficult and the person is unable to talk. Mental abilities generally decline into dementia, depression, apathy, and impulsivity at times. The specific symptoms vary somewhat between people. Symptoms usually begin between 30 and 50 years of age, and can start at any age but are usually seen around the age of 40. The disease may develop earlier in each successive generation. About eight percent of cases start before the age of 20 years, and are known as juvenile HD, which typically present with the slow movement symptoms of Parkinson's disease rather than those of chorea.
Sanfilippo syndrome, also known as mucopolysaccharidosis type III (MPS III), is a rare lifelong genetic disease that mainly affects the brain and spinal cord. It is caused by a problem with how the body breaks down certain large sugar molecules called glycosaminoglycans (also known as GAGs or mucopolysaccharides). In children with this condition, these sugar molecules build up in the body and eventually lead to damage of the central nervous system and other organ systems.
Alexander disease is a very rare autosomal dominant leukodystrophy, which are neurological conditions caused by anomalies in the myelin which protects nerve fibers in the brain. The most common type is the infantile form that usually begins during the first two years of life. Symptoms include mental and physical developmental delays, followed by the loss of developmental milestones, an abnormal increase in head size and seizures. The juvenile form of Alexander disease has an onset between the ages of 2 and 13 years. These children may have excessive vomiting, difficulty swallowing and speaking, poor coordination, and loss of motor control. Adult-onset forms of Alexander disease are less common. The symptoms sometimes mimic those of Parkinson's disease or multiple sclerosis, or may present primarily as a psychiatric disorder.
Progressive supranuclear palsy (PSP) is a late-onset neurodegenerative disease involving the gradual deterioration and death of specific volumes of the brain. The condition leads to symptoms including loss of balance, slowing of movement, difficulty moving the eyes, and cognitive impairment. PSP may be mistaken for other types of neurodegeneration such as Parkinson's disease, frontotemporal dementia and Alzheimer's disease. The cause of the condition is uncertain, but involves the accumulation of tau protein within the brain. Medications such as levodopa and amantadine may be useful in some cases.
Thalamotomy is a surgical procedure in which a functional lesion is made into the thalamus to improve the overall brain function in patients. First introduced in the 1950s, it is primarily effective for tremors such as those associated with Parkinson's disease, where a selected portion of the thalamus is surgically destroyed (ablated). Neurosurgeons use specialized equipment to precisely locate an area of the thalamus, usually choosing to work on only one side. Bilateral procedures are poorly tolerated because of increased complications and risk, including vision and speech problems. The positive effects on tremors are immediate. Other less destructive procedures are sometimes preferred, such as subthalamic deep brain stimulation, since this procedure can also improve tremors and other symptoms of PD.
Batten disease is a fatal disease of the nervous system that typically begins in childhood. Onset of symptoms is usually between 5 and 10 years of age. Often, it is autosomal recessive. It is the common name for a group of disorders called the neuronal ceroid lipofuscinoses (NCLs).
Metachromatic leukodystrophy (MLD) is a lysosomal storage disease which is commonly listed in the family of leukodystrophies as well as among the sphingolipidoses as it affects the metabolism of sphingolipids. Leukodystrophies affect the growth and/or development of myelin, the fatty covering which acts as an insulator around nerve fibers throughout the central and peripheral nervous systems. MLD involves cerebroside sulfate accumulation. Metachromatic leukodystrophy, like most enzyme deficiencies, has an autosomal recessive inheritance pattern.
Spinocerebellar ataxia (SCA) is a progressive, degenerative, genetic disease with multiple types, each of which could be considered a neurological condition in its own right. An estimated 150,000 people in the United States have a diagnosis of spinocerebellar ataxia at any given time. SCA is hereditary, progressive, degenerative, and often fatal. There is no known effective treatment or cure. SCA can affect anyone of any age. The disease is caused by either a recessive or dominant gene. In many cases people are not aware that they carry a relevant gene until they have children who begin to show signs of having the disorder. Currently, research is being conducted at Universities, such as the University of Minnesota, to elucidate many of the unknown characteristics of the disease.
Spinal and bulbar muscular atrophy (SBMA), popularly known as Kennedy's disease, is a rare, adult-onset, X-linked recessive lower motor neuron disease caused by trinucleotide CAG repeat expansions in exon 1 of the androgen receptor (AR) gene, which results in both loss of AR function and toxic gain of function.
Corticobasal degeneration (CBD) is a rare neurodegenerative disease involving the cerebral cortex and the basal ganglia. CBD symptoms typically begin in people from 50 to 70 years of age, and typical survival before death is eight years. It is characterized by marked disorders in movement and cognition, and is classified as one of the Parkinson plus syndromes. Diagnosis is difficult, as symptoms are often similar to those of other disorders, such as Parkinson's disease, progressive supranuclear palsy, and dementia with Lewy bodies, and a definitive diagnosis of CBD can only be made upon neuropathologic examination.
Omigapil is a drug that was developed by Novartis and tested in clinical trials for its ability to help treat Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). The development for PD and ALS have been terminated due to lack of benefit, but Santhera Pharmaceuticals bought the compound for development for the treatment of congenital muscular dystrophy (CMD).
Tauopathies are a class of neurodegenerative diseases characterized by the aggregation of abnormal tau protein. Hyperphosphorylation of tau proteins causes them to dissociate from microtubules and form insoluble aggregates called neurofibrillary tangles. Various neuropathologic phenotypes have been described based on the anatomical regions and cell types involved as well as the unique tau isoforms making up these deposits. The designation 'primary tauopathy' is assigned to disorders where the predominant feature is the deposition of tau protein. Alternatively, diseases exhibiting tau pathologies attributed to different and varied underlying causes are termed 'secondary tauopathies'. Some neuropathologic phenotypes involving tau protein are Alzheimer's disease, frontotemporal dementia, progressive supranuclear palsy, and corticobasal degeneration.
A neurodegenerative disease is caused by the progressive loss of neurons, in the process known as neurodegeneration. Neuronal damage may also ultimately result in their death. Neurodegenerative diseases include amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, Alzheimer's disease, Huntington's disease, multiple system atrophy, tauopathies, and prion diseases. Neurodegeneration can be found in the brain at many different levels of neuronal circuitry, ranging from molecular to systemic.Because there is no known way to reverse the progressive degeneration of neurons, these diseases are considered to be incurable; however research has shown that the two major contributing factors to neurodegeneration are oxidative stress and inflammation. Biomedical research has revealed many similarities between these diseases at the subcellular level, including atypical protein assemblies and induced cell death. These similarities suggest that therapeutic advances against one neurodegenerative disease might ameliorate other diseases as well.
In the management of Parkinson's disease, due to the chronic nature of Parkinson's disease (PD), a broad-based program is needed that includes patient and family education, support-group services, general wellness maintenance, exercise, and nutrition. At present, no cure for the disease is known, but medications or surgery can provide relief from the symptoms.
Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease of mainly the central nervous system that affects both the motor and non-motor systems of the body. The symptoms usually emerge slowly, and, as the disease progresses, non-motor symptoms become more common. Usual symptoms include tremors, slowness of movement, rigidity, and difficulty with balance, collectively known as parkinsonism. Parkinson's disease dementia, falls and neuropsychiatric problems such as sleep abnormalities, psychosis, mood swings, or behavioral changes may also arise in advanced stages.
The Pacific Udall Center was established in 2009 as a new Morris K. Udall Center of Excellence for Parkinson's Disease Research. It is one of nine Udall Centers across the U.S. that honor former Utah Congressman Morris Udall with a "multidisciplinary research approach to elucidate the fundamental causes of PD [Parkinson's Disease] as well as to improve the diagnosis and treatment of patients with Parkinson's and related neurodegenerative disorders." The Pacific Udall Center is a collaboration among Stanford University, the University of Washington, the VA Puget Sound Health Care System, Oregon Health & Science University, and the Portland VA Medical Center. It is funded by a grant from the National Institute of Neurological Disorders and Stroke.
Gene therapy in Parkinson's disease consists of the creation of new cells that produce a specific neurotransmitter (dopamine), protect the neural system, or the modification of genes that are related to the disease. Then these cells are transplanted to a patient with the disease. There are different kinds of treatments that focus on reducing the symptoms of the disease but currently there is no cure.
The Parkinson's Foundation is a national organization that funds research and provides educational resources to Parkinson's disease patients and caregivers. The Parkinson's Foundation was established in 2016 through the merger of the National Parkinson Foundation and the Parkinson's Disease Foundation. The Parkinson's Foundation has headquarters in Miami and New York City, in addition to 17 chapters throughout the United States.
The Shake It Up Australia Foundation (SIUAF) is an Australian non-for-profit foundation founded in 2011 by Clyde and Greg Campbell. It is partnered with the Michael J. Fox Foundation (MJFF) to achieve the foundations primary aims of "promoting and funding Parkinson's disease research in Australia to slow, stop and cure the disease". Together MJFF and SIUAF are the largest non-government funders of Parkinson's research across multiple institutes in Australia. Since its founding, the foundation has co-founded 38 Parkinson's research projects across 12 institutes to the value of over $10.8 million. The foundation's funding model ensures that 100% of proceeds goes towards Parkinson's research in Australia. This is possible due to the founding directors covering all overhead costs and expenses. In January 2019, Shake It Up are one of the partner organisation in the Australian Parkinson's Mission which was awarded a $30 million-dollar grant to test repurposed drugs in clinical trials.
Rapid eye movement sleep behaviour disorder and Parkinson's disease is rapid eye movement sleep behavior disorder (RBD) that is associated with Parkinson's disease. RBC is linked genetically and neuropathologically to α- synuclein, a presynaptic neuronal protein that exerts deleterious effects on neighbouring proteins, leading to neuronal death. This pathology is linked to numerous other neurodegenerative disorders, such as Lewy body dementias, and collectively these disorders are known as synucleinopathies. Numerous reports over the past few years have stated the frequent association of synucleinopathies with REM sleep behaviour disorder (RBD). In particular, the frequent association of RBD with Parkinson's. In the general population the incidence of RBD is around 0.5%, compared to the prevalence of RBD in PD patients, which has been reported to be between 38% and 60%. The diagnosis and symptom onset of RBD typically precedes the onset of motor or cognitive symptoms of PD by a number of years, typically ranging anywhere from 2 to 15 years prior. Hence, this link could provide an important window of opportunity in the implementation of therapies and treatments, that could prevent or slow the onset of PD.