• aggregate

    A whole formed by the combination of several elements. In Parkinson’s there is a clumping of many proteins inside nerve cells (known as neurons) including alpha-synuclein. Lewy bodies are a kind of aggregate found in Parkinson's.
  • agonist

    A chemical or drug that can activate a neurotransmitter receptor. Dopamine agonists, such as pramipexole, ropinirole, bromocriptine and apomorphine, are used in the treatment of Parkinson's.
  • alpha-synuclein

    A protein that is primarily found in nerve cells (neurons); in their cell body, their nucleus and their terminals. The accumulation and aggregation of this protein is a pathologic finding in Parkinson's. The first genetic mutation found in Parkinson's was discovered in the gene for alpha-synuclein (SNCA), and is called PARK1. Alpha-synuclein appears to play a key role in the pathogenesis of Parkinson's. Read more.
  • astrocytes

    Major support cells in the brain. Among other things, they secrete growth factors that help nerve cells (or neurons) grow and communicate.
  • autophagy

    The segregation and disposal of damaged organelles within a cell. This is a normal physiological process in the body. It maintains normal functioning by protein degradation and turnover of the destroyed cell organelles for new cell formation. During cellular stress the process of autophagy is increased.  Dysfunctional autophagy can lead to the build up of damaged organelles and misfolded proteins in the cell.
  • basal ganglia

    Clusters of neurons that include the caudate nucleus, putamen, globus pallidus and substantia nigra which are located deep in the brain and play an important role in movement. Cell death in the substantia nigra contributes to Parkinsonian signs.
  • biomarker

    An early indicator that a person may have a disease, such as Parkinson’s. A biomarker, if present, could indicate that the person has a disease before symptoms of that disease appear. There is a search for biomarkers for Parkinson's. Biomarkers could be a chemical, clinical, or imaging finding.
  • blood brain barrier

    The separating membrane between the blood and the brain; a semi-permeable physical barrier that protects against circulating toxins or pathogens that could cause brain infections while at the same time allowing vital nutrients to reach the brain.
  • c-Abl

    A gene implicated in the processes of cell differentiation, cell division, cell adhesion, and stress response.
  • calcium

    An essential mineral. Calcium is important for neurological "signalling" and is involved in many chemical reactions within nerve cells (or neurons) and in mitochondria function. Calcium overload in the substantia nigra has been postulated as one mechanism that could contribute to the death of these neurons.
  • cell replacement

    Cell replacement therapy  involves the restoring of lost function caused by damage or disease in the central nervous system by the replacement of dead cells with new healthy ones. Read more.
  • cerebrospinal fluid (CSF)

    A watery fluid generated within the brain's ventricles. CSF circulates to bathe the brain and spinal cord to cushion these from physical impact. Small amounts can be harvested by lumbar puncture to measure chemicals coming from the brain.
  • disease modification

    Treatments or interventions that affect the underlying pathophysiology of Parkinson's and have a beneficial outcome on the course of the disease.
  • dopamine

    A small chemical molecule that is one of the brain's neurotransmitters. Among other brain regions, it is found in cells within the substantia nigra. These cells project to the striatum in the basal ganglia. Deficiency of dopamine in the striatum due to the death of cells in the substantia nigra causes symptoms of Parkinsonism.
  • dopaminergic pathways

    Neural pathways in the brain which utilise dopamine as their neurotransmitter.
  • drug repurposing

    Repurposing generally refers to studying drugs that are already approved to treat one disease or condition to see if they are safe and effective for treating another.
  • exosomes

    Small ball-like structures produced by cells and which can be found in body fluids such as blood, urine, and CSF and cultured medium of cell cultures. They are formed inside the cell and during this process they engulf some cellular fluid and contents.
  • GBA

    The GBA gene provides instructions for making an enzyme called glucocerebrosidase, found within cells. Mutations in the GBA gene are associated with Parkinson's. Read more.
  • GCase – glucocerebrosidase

    A protein which helps break down fats and other proteins. The GBA gene directs the production of the GCase protein and GBA mutations significantly decrease GCase activity in the Parkinsonian brain.
  • GDNF

    Glial Cell-line derived nerve growth factor.
  • gene therapy

    The insertion of genes into an individual's cells and tissues to treat hereditary diseases where deleterious mutant alleles can be replaced with functional ones. The genes are usually put inside a non-pathogenic virus, which serves as the mechanism to penetrate the cells. Gene therapy can also be used to correct non-genetic deficiencies such as the loss of dopamine in Parkinson's, to modify the function of a group of cells or to provide a source of growth factors.
  • genotype

    The collection of genetic material of an individual that gives rise to its characteristics
  • glial cells

    Non-neural cells, commonly called neuroglia or simply glia (Greek for "glue"), that maintain and provide support and protection for the brain's cells (or neurons). Astrocytes are one kind of glial cells.
  • GLP-1

    This diabetes medication works by increasing the levels of hormones called ‘incretins’. These hormones help the body produce more insulin only when needed and reduce the amount of glucose being produced by the liver when it’s not needed.
  • growth factors

    Naturally occurring substances (usually proteins) that help maintain the health of cells and encourage cell growth, proliferation and differentiation. Some growth factors are being looked at to try to promote the survival of the neural cells that are degenerating in Parkinson's.
  • gut microbiome

    The complex community of microorganisms that live in the digestive tracts of humans and other animals.
  • idiopathic

    Arising from an unknown cause.
  • inflammasome

    Chronic inflammation is recognised as a causative factor of Parkinson's. The 'NLRP3 inflammasome' is a multi-protein complex that initiates an inflammatory form of cell death and is especially active in Parkinson's.
  • iPS cells

    Stem cells that can be generated directly from adult cells.
  • leucine rich repeat kinase 2 (LRRK2)

    A protein created by the LRRK2 gene which when mutated can lead to Parkinson’s. Several different mutations in the LRRK2 gene have been found to cause Parkinson’s but there may also be variants within the general population that do not necessarily cause disease.
  • Lewy bodies

    A pathological feature of Parkinson's. Lewy bodies are abnormal aggregates of protein masses seen microscopically in neurons in several brain regions. One protein seen is alpha-synuclein in an aggregated form.
  • microglia

    A type of glial cell; it provides the first immune defense mechanism in the brain and central nervous system.
  • mitochondria

    A spherical or elongated organelle in the cytoplasm of nearly all living cells, containing genetic material and many enzymes important for cell metabolism, including those responsible for the conversion of food to useable energy.
  • neuroinflammation

    The swelling of the tissue in the nervous system. It could be initiated in response to a number of things including infection, traumatic brain injury, toxic metabolites, or autoimmunity. Microglia are the immune cells activated in response to these cues.
  • neuron

    A nerve cell that is the fundamental unit of the brain and nervous system. Neurons transmit information through electrochemical signals.
  • neurotrophic factors

    A family of biomolecules that support the growth, survival, and differentiation of both developing and mature nerve cells (neurons).
  • oxidative stress

    Oxidative stress is an imbalance of free radicals and antioxidants in the body, which can lead to cell and tissue damage. Oxidative stress occurs naturally and plays a role in the aging process.
  • pathogenesis

    The underlying biological mechanisms of a disease.
  • PINK-1

    An abbreviation for the name of a gene that encodes a particular protein found in mitochondria that is thought to protect cells from stress-induced mitochondrial dysfunction. Lack of PINK-1 causes an overload of calcium in mitochondria and indirectly cell death.
  • placebo

    A simulated or inert form of treatment without known proven benefit on a symptom or a disease. Placebos are employed in controlled clinical trials along with the active drug being tested; patients and health professionals involved in the trial do not know who receives the placebo or the drug. The difference in responses between the two drugs is considered the true effect of the active drug.
  • prodromal

    Referring to the period before the classic manifestation of a disease leading to diagnosis.
  • stem cell

    Biological cells found in all multicellular organisms, that can divide (through mitosis) and differentiate into diverse specialised cell types and can self-renew to produce more stem cells. They are a potential line of treatment in Parkinson’s, either by directly replacing neuronal cells or by creating growth factor releasing cells.
  • Unified Parkinson’s Disease Rating Scale (UPDRS)

    A rating scale used to measure the severity of Parkinson's. The UPDRS can follow a person's worsening over time and also measure improvement with various treatments.

With thanks to World Parkinson’s Coalition.