UKPDSTB General: Brain Bank Bulletin issue 8, page 2

Page 2 of 4 Brain Bank Bulletin
The PDS Tissue Bank is sponsored by the Parkinson's Disease Society Issue 8
Spring 2007

Inside this issue:

Questions 1 Research Report:
Dementia and Hallucinations 2 Research Report:
RNA Quality 3 Contact Info 4

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For example, confusion and hallucinations, dyskinesias or involuntary movements, freezing and on/off episodes may all have significance for specific brain regions and chemical activities and without detailed information the researcher cannot address these problems while studying the brain. Thus, if we lose the information about these problems during treatment we also lose the opportunity to understand them better when looking at brain tissue itself.
The Changing Story
We now know that Parkinson's is often far more than a problem with tremor and poor movement and we need to understand better how and why the condition can cause symptoms from memory loss to poor sleep, from skin rash to poor bladder control. While symptoms may begin with movement problems and tremor, the picture most often changes over time. To be sure that the researcher can find the exact area where specific problems are coming from we need to have an accurate story from each brain donor. Every patient has a different experience with Parkinson's and some symptoms are rare while others are more common. Without the individual story of the person living with Parkinson’s there can be no accurate assessment of the brain leading to a better understanding of how the illness involves individual parts of the nervous system. This is the very knowledge that we need in order to discover better treatments and a cure.
Therefore, the 100 questions will be sent out to our donors on a regular basis so that we can learn about facts as diverse as bowel and bladder function, drooling and poor speech, memory and concentration, dizzy spells related to low blood pressure, sleep and dreams and many other things including drug treatments for Parkinson's and other illnesses. With these facts describing all symptoms and side effects the Tissue Bank will be able to provide researchers with sufficient knowledge to ensure that each brain donation is made as valuable as possible.
Dr Ronald Pearce, Clinical Neurologist

Research Project Report: Studies on the pathological basis of dementia and visual hallucinations in PD

Parkinson's disease (PD) has been characterised as a movement disorder with the main clinical features of resting tremor, bradykinesia, rigidity and abnormalities of gait, balance and posture. This underestimates the complexity of what is a multi-system disorder with many important non-motor features. Among the most prominent non-motor complications of the disease are dementia and visual hallucinations The prevalence of dementia in PD has been reported to be between 12 and 41% with PD patients having a six-fold risk for dementia over age-matched controls. Prevalence figures for visual hallucinations are in the range of 6-60%.

Fig 1. The nucleus basalis of Meynert from a patient with Parkinson's disease contains alpha-synuclein positive Lewy bodies (shown with the arrow) and Lewy Neurites (arrowhead).

Fig 2. The entorhinal cortex of a Parkinson's disease patient containing tau positive neurofibrillary tangles (shown with the arrows) and neuropil threads (arrowhead).

Pathologically, PD is characterised by loss of cells in the substantia nigra pars compacta. However, it is now apparent that there is a widespread pathology in PD that greatly exceeds the classical brainstem 'locus classicus' of the substantia nigra pars compacta. Abnormal accumulation of a protein called alpha synuclein is a histopathological marker of the disease with Lewy Bodies and Lewy Neurites containing alpha synuclein (Fig 1). Nonetheless, other abnormally deposited proteins can also be found such as hyperphosphorylated tau and beta-amyloid that are characteristic neuropathological hallmarks of Alzheimer's disease (Fig 2 and 3). These abnormal proteins can be found in areas other than the substania nigra and we wanted to investigate how the location of these abnormal proteins correlate with the prevalence of dementia and hallunciations. This will help us understand how we may stave off the progress of PDD and prevent hallucinations.

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