The Psychology of a Prion

Sarah Themel

This is your brain…

This is Your Brain on Prions

What is a Prion?• Prion diseases are called spongiform encephalopathies. They

impair brain functions, leading to both mental and physical deterioration over short periods of time.

• Though few have heard the term “prion,” almost everyone has heard of the diseases they cause.

• They have been found in MANY species• Their structure is extremely stable, making them nearly indestructible. That is why there is no known cure or treatment for any disease caused by prions; they are ALWAYS

fatal. Most victims remain cognitive and wellaware of their situation up until death.

• Diseases caused by prions can be: sporadic, infectious, and genetic. No other disease has the ability to infect in all three ways.• Different strains of prions cause specific and very distinct diseases.

PrP and Me• The protein PrP is found throughout our bodies; it’s exact purpose is unknown• A prion is this same exact protein misfolded, or mutated, changing it’s structure. This new structure is called

PrPSC , aka a prion.• The prions link up, joining together to form prion rods. The rods accumulate in the brain, causing:

Tissue damage, cell death, loss of neurons, neuronal swelling, proliferation of astrocytes (these are star shaped cells that are usually a sign of the brains attempt to repair damage),and gliosis (the proliferation of infection fighting cells in the brain)Prions are also responsible for the formation of amyloid plaques that lead to neurodegeneration (also found in other neurodegenerative diseases like Alzheimer's)

CJD and Me• Weakness and pain in legs, which leads to stiffness and changes in gait. Eventually patients lose

their ability to walk.• clumsiness or incordination; Muscle twitching and shaking• Disturbances of general motor skills and sensation• Dementia and other psychiatric and behavioral problems. These striking mental changes include:

mood swings, depression, anxiety, memory lapses, social withdrawal, disorientation, hallucinations, and extreme dementia

• Rare cases can also lead to seizures and blindness

CJD• Creutzfeldt–Jakob Disease (CJD) is the most common type of transmissible spongiform

encephalopathy found in humans• Severe thalamic and basal ganglia gliosis along with spongiform changes are the most

prominent histological features.• It can be either genetic (with a 50% chance of passing it to offspring) or sporadic (appearing

for no known reason). There are also several variations.• It was first described in 1920 and now affects 1/1,000,000 people a year• 80% of cases occur between the ages of 50-70 • death usually occurs 4-5 months after the onset of symptoms• It’s a degenerative neurological disorder that is very rare, incurable, and always fatal

Kuru and You• Begins with a headache and pain in the limbs• Glassy eyes/cross eyed• As it progresses, unsteady gait and incordination ; loss of balance and clumsiness• Muscle jerks and trembling spasms occur (kuru means to tremble or shiver)• Muscles spasms make victims appear to chuckle or giggle• Patients lose control of voluntary movements, such as the ability to stand • Emotional instability. Victims often become belligerent or aggressive• Damage to the muscle timing areas of the brain cause the muscles used for swallowing stop working and

speech to slur. (Many victims died of starvation).• Though mute and unable to move, victims remain cognitive and are well aware of what’s going on

Kuru• Kuru is a prion disease that was found in the Fore tribe of Papua New Guinea• First described in 1950, it is well known today as the disease caused by cannibalism. Kuru

probably began as a sporadic case of CJD and spread as infected brains were consumed.• This disease killed off 1/3 of the women and child population and nearly 15% of the entire

population. Death within 12-18 months after onset in adults, 3-12 months in children.• Kuru stopped spreading with the end of cannibalism, but cases occurring later proved that the

disease could stay in incubation for over 40 years• It causes significant damage to the cerebellum (which controls motor functions)

GSS and Us• Gradually worsening

inbalance while walking or standing and poor cordination

• Unable to walk a straight line without swaggering

• rigid muscle tone and strange reflexes

• Visual disturbances (sometimes blindness) and deafness

• involuntary movements of the eyes

• Impaired ability to swallow

• Personality changes (irritable, intolerant, yet often unexplainably cheerful)

• Progressive decrease in intelligence and memory loss

• Eventually full blown and progressive dementia, caused by deposits of gray matter in the cerebral cortex

GSS • Gerstmann–Sträussler–Scheinker syndrome syndrome (GSS) is a genetically inherited prion disease• Occurs 1/15,000,000, with a 50% chance of passing on the gene• This hereditary disease occurs in about 4 dozen families around the world today• GSS was the first disease to prove that the prion could be both infectious and hereditary• Usually occurs around age 50 with death occurring 2-7 years after initial symptoms• This disease causes amayloid plaque deposits, which mostly accumulate in the cerebral cortex and

the basal ganglia

FFI and a GuyInsomnia (eventually sleep becomes impossible)• Extreme sweating and a wildly gyrating body temperature

Muscle problems such as twitching, stiffness and spasms.

• Clumsy walking, trembling in the limbs, and involuntary muscle contraction• Depression, m o o d changes, panic attacks and phobias. • Vivid dreams and hallucinations

• Acting out and gesturing during

stupors of dreamlike states• Lack of sleep leads to extreme• fatigue and changes in

hormone levels (not fallowing the circadian rhythm)• Victims become unresponsive or

mute as dementia sets in• Comma, followed by death

FFI• Introduced in 1986, Fatal Familial Insomnia occurs 1/33,000,000 people• It is a genetic disease, having a 50% chance of inheritance. There have been 7 reported cases of the

disease appearing sporadically without a genetic mutation.• FFI can present in two forms. In victims that have the early onset form, the symptoms are predominantly

mental. Early onset develops slower, patients can live as long as 36 months. Victims with the form that occurs later in life, usually around age 50, experience symptoms predominately associated with insomnia. Victims of late onset usually die within 12 months.

• Damage to the anterior and dorsomedial nuclei of the thalamus is the most notable effect of FFI on the brain. When a victim lives long enough, cerebral cortex spongiform changes also occur.

vCJD and an Entire Country• Within 4 months of the onset, poor memory and an unsteady gait develop• Unusual sensory symptoms • Jerky movements, involuntary muscle contractions, and muscle paralysis• visual deterioration and eventual blindness• slurred speech, difficulty swallowing• Incontinence• Increasingly intense hallucinations• depression, withdrawal, anxiety, trouble sleeping, and schizophrenia-like psychosis• Increasing, extreme dementia• Patients become completely immobile and mute, and eventually lapse into a coma which is fallowed by

death

vCJD• Variant Creutzfeldt-Jakob Disease is more commonly known as mad cow disease • vCJD is acquired from eating beef tainted with bovine spongiform encephalopathy (BSE).• In the 1980s BSE was found in cattle throughout Britain. Infected cattle entered the food chain and was passed on

to humans through the consumption of prion infested meat• The age of onset is typically younger than regular CJD, with an average onset at 29 years old. The duration of the

disease is usually longer than CJD, with death around 14 months of onset. • So far, most cases have occurred in the UK. By February 2009, vCJD had killed 164 people in Britain, and 42

elsewhere. This spongiform encephalopathy has also killed zoo animals, other livestock, and even household pets that were fed infected meat

• Area’s of the brain damaged by vCJD tend to be consistent with CJD’s known targets, but there are more extensive spongiform changes. It effects hippocampus, thalamus, basal ganglia, cerebellum, and lymphatic tissue.

A Bystander ReminderPatients aren’t the only victims of prion diseases…

CJD victim Jonathan Simms and his father Don.

conclusionThough rare, prion disease are a force to be reckoned with. The sheer thought of something eating brains is frightening. Many physical as well as psychological effects are experienced by

their victims, who are aware of their own state up until the end. All cases lead to death. They leave a path of traumatized onlookers on their trail of death. They are one of the

scariest pathogens known to man, they are also one of the most interesting microbes in existence.

Works Cited• Yam, Philip. The Pathological Protein. New York: Copernicus Books, 2003

• Max, D.T. The Family That Couldn’t Sleep. Random House, 2006

• Collins, Kumar. Robbins Pathologic Basis of Disease. Philadelphia: W.B Saunders Company, 1998

• Rhodes, Richard. Deadly Feasts. New York: Simon & Schuster, 1997

• “The Brain Eater”. By Joseph McMaster. Dir. Alan Ritsko. NOVA. PBS. February 10, 1998.

• http://www.cjdfoundation.org/

• http://www.who.int/en/

PHOTOS:http://www.belfasttelegraph.co.uk/sunday-life/cjd-survivor-still-defying-the-odds-14121775.htmlhttp://www.time.com/time/europe/photoessays/cjd/http://www.biologie.uni-duesseldorf.de/Institute/Physikalische_Biologie/Research/Topics/addinformation2http://medicalworldofmine.blogspot.com/2008/06/choosing-nursing-home-for-alzheimers.htmlhttp://www.best-sleepaid.com/causes-of-insomnia/